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* [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
@ 2021-01-30  7:10 ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X.
crashkernel=X tries low allocation in DMA zone and fall back to high
allocation if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices. So there may be two regions reserved for
crash dump kernel.
In order to distinct from the high region and make no effect to the use
of existing kexec-tools, rename the low region as "Crash kernel (low)",
and pass the low region by reusing DT property
"linux,usable-memory-range". We made the low memory region as the last
range of "linux,usable-memory-range" to keep compatibility with existing
user-space and older kdump kernels.

Besides, we need to modify kexec-tools:
arm64: support more than one crash kernel regions(see [1])

Another update is document about DT property 'linux,usable-memory-range':
schemas: update 'linux,usable-memory-range' node schema(see [2])

This patchset contains the following eleven patches:
0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
0008-arm64-kdump-reimplement-crashkernel-X.patch
0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
0011-kdump-update-Documentation-about-crashkernel.patch

0001-0004 are some x86 cleanups which prepares for making
functionsreserve_crashkernel[_low]() generic.
0005 makes functions reserve_crashkernel[_low]() generic.
0006 fix compiling warning.
0007-0009 reimplements arm64 crashkernel=X.
0010 adds memory for devices by DT property linux,usable-memory-range.
0011 updates the doc.

Changes since [v13]
- Rebased on top of 5.11-rc5.
- Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
Since reserve_crashkernel[_low]() implementations are quite similar on
other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
arch/Kconfig and select this by X86 and ARM64.
- Some minor cleanup.

Changes since [v12]
- Rebased on top of 5.10-rc1.
- Keep CRASH_ALIGN as 16M suggested by Dave.
- Drop patch "kdump: add threshold for the required memory".
- Add Tested-by from John.

Changes since [v11]
- Rebased on top of 5.9-rc4.
- Make the function reserve_crashkernel() of x86 generic.
Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
and arm64 use the generic version to reimplement crashkernel=X.

Changes since [v10]
- Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.

Changes since [v9]
- Patch 1 add Acked-by from Dave.
- Update patch 5 according to Dave's comments.
- Update chosen schema.

Changes since [v8]
- Reuse DT property "linux,usable-memory-range".
Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
memory region.
- Fix kdump broken with ZONE_DMA reintroduced.
- Update chosen schema.

Changes since [v7]
- Move x86 CRASH_ALIGN to 2M
Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
- Update Documentation/devicetree/bindings/chosen.txt.
Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
suggested by Arnd.
- Add Tested-by from Jhon and pk.

Changes since [v6]
- Fix build errors reported by kbuild test robot.

Changes since [v5]
- Move reserve_crashkernel_low() into kernel/crash_core.c.
- Delete crashkernel=X,high.
- Modify crashkernel=X,low.
If crashkernel=X,low is specified simultaneously, reserve spcified size low
memory for crash kdump kernel devices firstly and then reserve memory above 4G.
In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
pass to crash dump kernel by DT property "linux,low-memory-range".
- Update Documentation/admin-guide/kdump/kdump.rst.

Changes since [v4]
- Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.

Changes since [v3]
- Add memblock_cap_memory_ranges back for multiple ranges.
- Fix some compiling warnings.

Changes since [v2]
- Split patch "arm64: kdump: support reserving crashkernel above 4G" as
two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
patch.

Changes since [v1]:
- Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
- Remove memblock_cap_memory_ranges() i added in v1 and implement that
in fdt_enforce_memory_region().
There are at most two crash kernel regions, for two crash kernel regions
case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
and then remove the memory range in the middle.

[1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
[2]: https://github.com/robherring/dt-schema/pull/19 
[v1]: https://lkml.org/lkml/2019/4/2/1174
[v2]: https://lkml.org/lkml/2019/4/9/86
[v3]: https://lkml.org/lkml/2019/4/9/306
[v4]: https://lkml.org/lkml/2019/4/15/273
[v5]: https://lkml.org/lkml/2019/5/6/1360
[v6]: https://lkml.org/lkml/2019/8/30/142
[v7]: https://lkml.org/lkml/2019/12/23/411
[v8]: https://lkml.org/lkml/2020/5/21/213
[v9]: https://lkml.org/lkml/2020/6/28/73
[v10]: https://lkml.org/lkml/2020/7/2/1443
[v11]: https://lkml.org/lkml/2020/8/1/150
[v12]: https://lkml.org/lkml/2020/9/7/1037
[v13]: https://lkml.org/lkml/2020/10/31/34

Chen Zhou (11):
  x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  x86: kdump: make the lower bound of crash kernel reservation
    consistent
  x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
    reserve_crashkernel()
  x86: kdump: move xen_pv_domain() check and insert_resource() to
    setup_arch()
  x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
  x86/elf: Move vmcore_elf_check_arch_cross to
    arch/x86/include/asm/elf.h
  arm64: kdump: introduce some macroes for crash kernel reservation
  arm64: kdump: reimplement crashkernel=X
  x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  arm64: kdump: add memory for devices by DT property
    linux,usable-memory-range
  kdump: update Documentation about crashkernel

 Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
 .../admin-guide/kernel-parameters.txt         |  11 +-
 arch/Kconfig                                  |   3 +
 arch/arm64/Kconfig                            |   1 +
 arch/arm64/include/asm/kexec.h                |  10 ++
 arch/arm64/kernel/setup.c                     |  13 +-
 arch/arm64/mm/init.c                          | 111 +++++-------
 arch/x86/Kconfig                              |   2 +
 arch/x86/include/asm/elf.h                    |   3 +
 arch/x86/include/asm/kexec.h                  |  31 +++-
 arch/x86/kernel/setup.c                       | 163 ++----------------
 include/linux/crash_core.h                    |   3 +
 include/linux/kexec.h                         |   2 -
 kernel/crash_core.c                           | 156 +++++++++++++++++
 kernel/kexec_core.c                           |  17 --
 15 files changed, 303 insertions(+), 245 deletions(-)

-- 
2.20.1


^ permalink raw reply	[flat|nested] 126+ messages in thread
* [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
@ 2021-01-30  7:10 ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, chenzhou10, linux-doc, kexec,
	linux-kernel, robh+dt, horms, james.morse, huawei.libin,
	guohanjun, linux-arm-kernel

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X.
crashkernel=X tries low allocation in DMA zone and fall back to high
allocation if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices. So there may be two regions reserved for
crash dump kernel.
In order to distinct from the high region and make no effect to the use
of existing kexec-tools, rename the low region as "Crash kernel (low)",
and pass the low region by reusing DT property
"linux,usable-memory-range". We made the low memory region as the last
range of "linux,usable-memory-range" to keep compatibility with existing
user-space and older kdump kernels.

Besides, we need to modify kexec-tools:
arm64: support more than one crash kernel regions(see [1])

Another update is document about DT property 'linux,usable-memory-range':
schemas: update 'linux,usable-memory-range' node schema(see [2])

This patchset contains the following eleven patches:
0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
0008-arm64-kdump-reimplement-crashkernel-X.patch
0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
0011-kdump-update-Documentation-about-crashkernel.patch

0001-0004 are some x86 cleanups which prepares for making
functionsreserve_crashkernel[_low]() generic.
0005 makes functions reserve_crashkernel[_low]() generic.
0006 fix compiling warning.
0007-0009 reimplements arm64 crashkernel=X.
0010 adds memory for devices by DT property linux,usable-memory-range.
0011 updates the doc.

Changes since [v13]
- Rebased on top of 5.11-rc5.
- Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
Since reserve_crashkernel[_low]() implementations are quite similar on
other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
arch/Kconfig and select this by X86 and ARM64.
- Some minor cleanup.

Changes since [v12]
- Rebased on top of 5.10-rc1.
- Keep CRASH_ALIGN as 16M suggested by Dave.
- Drop patch "kdump: add threshold for the required memory".
- Add Tested-by from John.

Changes since [v11]
- Rebased on top of 5.9-rc4.
- Make the function reserve_crashkernel() of x86 generic.
Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
and arm64 use the generic version to reimplement crashkernel=X.

Changes since [v10]
- Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.

Changes since [v9]
- Patch 1 add Acked-by from Dave.
- Update patch 5 according to Dave's comments.
- Update chosen schema.

Changes since [v8]
- Reuse DT property "linux,usable-memory-range".
Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
memory region.
- Fix kdump broken with ZONE_DMA reintroduced.
- Update chosen schema.

Changes since [v7]
- Move x86 CRASH_ALIGN to 2M
Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
- Update Documentation/devicetree/bindings/chosen.txt.
Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
suggested by Arnd.
- Add Tested-by from Jhon and pk.

Changes since [v6]
- Fix build errors reported by kbuild test robot.

Changes since [v5]
- Move reserve_crashkernel_low() into kernel/crash_core.c.
- Delete crashkernel=X,high.
- Modify crashkernel=X,low.
If crashkernel=X,low is specified simultaneously, reserve spcified size low
memory for crash kdump kernel devices firstly and then reserve memory above 4G.
In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
pass to crash dump kernel by DT property "linux,low-memory-range".
- Update Documentation/admin-guide/kdump/kdump.rst.

Changes since [v4]
- Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.

Changes since [v3]
- Add memblock_cap_memory_ranges back for multiple ranges.
- Fix some compiling warnings.

Changes since [v2]
- Split patch "arm64: kdump: support reserving crashkernel above 4G" as
two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
patch.

Changes since [v1]:
- Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
- Remove memblock_cap_memory_ranges() i added in v1 and implement that
in fdt_enforce_memory_region().
There are at most two crash kernel regions, for two crash kernel regions
case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
and then remove the memory range in the middle.

[1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
[2]: https://github.com/robherring/dt-schema/pull/19 
[v1]: https://lkml.org/lkml/2019/4/2/1174
[v2]: https://lkml.org/lkml/2019/4/9/86
[v3]: https://lkml.org/lkml/2019/4/9/306
[v4]: https://lkml.org/lkml/2019/4/15/273
[v5]: https://lkml.org/lkml/2019/5/6/1360
[v6]: https://lkml.org/lkml/2019/8/30/142
[v7]: https://lkml.org/lkml/2019/12/23/411
[v8]: https://lkml.org/lkml/2020/5/21/213
[v9]: https://lkml.org/lkml/2020/6/28/73
[v10]: https://lkml.org/lkml/2020/7/2/1443
[v11]: https://lkml.org/lkml/2020/8/1/150
[v12]: https://lkml.org/lkml/2020/9/7/1037
[v13]: https://lkml.org/lkml/2020/10/31/34

Chen Zhou (11):
  x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  x86: kdump: make the lower bound of crash kernel reservation
    consistent
  x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
    reserve_crashkernel()
  x86: kdump: move xen_pv_domain() check and insert_resource() to
    setup_arch()
  x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
  x86/elf: Move vmcore_elf_check_arch_cross to
    arch/x86/include/asm/elf.h
  arm64: kdump: introduce some macroes for crash kernel reservation
  arm64: kdump: reimplement crashkernel=X
  x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  arm64: kdump: add memory for devices by DT property
    linux,usable-memory-range
  kdump: update Documentation about crashkernel

 Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
 .../admin-guide/kernel-parameters.txt         |  11 +-
 arch/Kconfig                                  |   3 +
 arch/arm64/Kconfig                            |   1 +
 arch/arm64/include/asm/kexec.h                |  10 ++
 arch/arm64/kernel/setup.c                     |  13 +-
 arch/arm64/mm/init.c                          | 111 +++++-------
 arch/x86/Kconfig                              |   2 +
 arch/x86/include/asm/elf.h                    |   3 +
 arch/x86/include/asm/kexec.h                  |  31 +++-
 arch/x86/kernel/setup.c                       | 163 ++----------------
 include/linux/crash_core.h                    |   3 +
 include/linux/kexec.h                         |   2 -
 kernel/crash_core.c                           | 156 +++++++++++++++++
 kernel/kexec_core.c                           |  17 --
 15 files changed, 303 insertions(+), 245 deletions(-)

-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
@ 2021-01-30  7:10 ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, chenzhou10, linux-doc, kexec,
	linux-kernel, robh+dt, horms, james.morse, huawei.libin,
	guohanjun, linux-arm-kernel

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X.
crashkernel=X tries low allocation in DMA zone and fall back to high
allocation if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices. So there may be two regions reserved for
crash dump kernel.
In order to distinct from the high region and make no effect to the use
of existing kexec-tools, rename the low region as "Crash kernel (low)",
and pass the low region by reusing DT property
"linux,usable-memory-range". We made the low memory region as the last
range of "linux,usable-memory-range" to keep compatibility with existing
user-space and older kdump kernels.

Besides, we need to modify kexec-tools:
arm64: support more than one crash kernel regions(see [1])

Another update is document about DT property 'linux,usable-memory-range':
schemas: update 'linux,usable-memory-range' node schema(see [2])

This patchset contains the following eleven patches:
0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
0008-arm64-kdump-reimplement-crashkernel-X.patch
0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
0011-kdump-update-Documentation-about-crashkernel.patch

0001-0004 are some x86 cleanups which prepares for making
functionsreserve_crashkernel[_low]() generic.
0005 makes functions reserve_crashkernel[_low]() generic.
0006 fix compiling warning.
0007-0009 reimplements arm64 crashkernel=X.
0010 adds memory for devices by DT property linux,usable-memory-range.
0011 updates the doc.

Changes since [v13]
- Rebased on top of 5.11-rc5.
- Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
Since reserve_crashkernel[_low]() implementations are quite similar on
other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
arch/Kconfig and select this by X86 and ARM64.
- Some minor cleanup.

Changes since [v12]
- Rebased on top of 5.10-rc1.
- Keep CRASH_ALIGN as 16M suggested by Dave.
- Drop patch "kdump: add threshold for the required memory".
- Add Tested-by from John.

Changes since [v11]
- Rebased on top of 5.9-rc4.
- Make the function reserve_crashkernel() of x86 generic.
Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
and arm64 use the generic version to reimplement crashkernel=X.

Changes since [v10]
- Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.

Changes since [v9]
- Patch 1 add Acked-by from Dave.
- Update patch 5 according to Dave's comments.
- Update chosen schema.

Changes since [v8]
- Reuse DT property "linux,usable-memory-range".
Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
memory region.
- Fix kdump broken with ZONE_DMA reintroduced.
- Update chosen schema.

Changes since [v7]
- Move x86 CRASH_ALIGN to 2M
Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
- Update Documentation/devicetree/bindings/chosen.txt.
Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
suggested by Arnd.
- Add Tested-by from Jhon and pk.

Changes since [v6]
- Fix build errors reported by kbuild test robot.

Changes since [v5]
- Move reserve_crashkernel_low() into kernel/crash_core.c.
- Delete crashkernel=X,high.
- Modify crashkernel=X,low.
If crashkernel=X,low is specified simultaneously, reserve spcified size low
memory for crash kdump kernel devices firstly and then reserve memory above 4G.
In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
pass to crash dump kernel by DT property "linux,low-memory-range".
- Update Documentation/admin-guide/kdump/kdump.rst.

Changes since [v4]
- Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.

Changes since [v3]
- Add memblock_cap_memory_ranges back for multiple ranges.
- Fix some compiling warnings.

Changes since [v2]
- Split patch "arm64: kdump: support reserving crashkernel above 4G" as
two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
patch.

Changes since [v1]:
- Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
- Remove memblock_cap_memory_ranges() i added in v1 and implement that
in fdt_enforce_memory_region().
There are at most two crash kernel regions, for two crash kernel regions
case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
and then remove the memory range in the middle.

[1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
[2]: https://github.com/robherring/dt-schema/pull/19 
[v1]: https://lkml.org/lkml/2019/4/2/1174
[v2]: https://lkml.org/lkml/2019/4/9/86
[v3]: https://lkml.org/lkml/2019/4/9/306
[v4]: https://lkml.org/lkml/2019/4/15/273
[v5]: https://lkml.org/lkml/2019/5/6/1360
[v6]: https://lkml.org/lkml/2019/8/30/142
[v7]: https://lkml.org/lkml/2019/12/23/411
[v8]: https://lkml.org/lkml/2020/5/21/213
[v9]: https://lkml.org/lkml/2020/6/28/73
[v10]: https://lkml.org/lkml/2020/7/2/1443
[v11]: https://lkml.org/lkml/2020/8/1/150
[v12]: https://lkml.org/lkml/2020/9/7/1037
[v13]: https://lkml.org/lkml/2020/10/31/34

Chen Zhou (11):
  x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  x86: kdump: make the lower bound of crash kernel reservation
    consistent
  x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
    reserve_crashkernel()
  x86: kdump: move xen_pv_domain() check and insert_resource() to
    setup_arch()
  x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
  x86/elf: Move vmcore_elf_check_arch_cross to
    arch/x86/include/asm/elf.h
  arm64: kdump: introduce some macroes for crash kernel reservation
  arm64: kdump: reimplement crashkernel=X
  x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  arm64: kdump: add memory for devices by DT property
    linux,usable-memory-range
  kdump: update Documentation about crashkernel

 Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
 .../admin-guide/kernel-parameters.txt         |  11 +-
 arch/Kconfig                                  |   3 +
 arch/arm64/Kconfig                            |   1 +
 arch/arm64/include/asm/kexec.h                |  10 ++
 arch/arm64/kernel/setup.c                     |  13 +-
 arch/arm64/mm/init.c                          | 111 +++++-------
 arch/x86/Kconfig                              |   2 +
 arch/x86/include/asm/elf.h                    |   3 +
 arch/x86/include/asm/kexec.h                  |  31 +++-
 arch/x86/kernel/setup.c                       | 163 ++----------------
 include/linux/crash_core.h                    |   3 +
 include/linux/kexec.h                         |   2 -
 kernel/crash_core.c                           | 156 +++++++++++++++++
 kernel/kexec_core.c                           |  17 --
 15 files changed, 303 insertions(+), 245 deletions(-)

-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
function reserve_crashkernel() also used 1M alignment. So just
replace hard-coded alignment 1M with macro CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h | 3 +++
 arch/x86/kernel/setup.c      | 5 +----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 6802c59e8252..be18dc7ae51f 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -18,6 +18,9 @@
 
 # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
 
+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN		SZ_16M
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3412c4595efd..da769845597d 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -390,9 +390,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 
 #ifdef CONFIG_KEXEC_CORE
 
-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGN		SZ_16M
-
 /*
  * Keep the crash kernel below this limit.
  *
@@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
 	} else {
 		unsigned long long start;
 
-		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
 						  crash_base + crash_size);
 		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - memory is in use.\n");
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
function reserve_crashkernel() also used 1M alignment. So just
replace hard-coded alignment 1M with macro CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h | 3 +++
 arch/x86/kernel/setup.c      | 5 +----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 6802c59e8252..be18dc7ae51f 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -18,6 +18,9 @@
 
 # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
 
+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN		SZ_16M
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3412c4595efd..da769845597d 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -390,9 +390,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 
 #ifdef CONFIG_KEXEC_CORE
 
-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGN		SZ_16M
-
 /*
  * Keep the crash kernel below this limit.
  *
@@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
 	} else {
 		unsigned long long start;
 
-		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
 						  crash_base + crash_size);
 		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - memory is in use.\n");
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
function reserve_crashkernel() also used 1M alignment. So just
replace hard-coded alignment 1M with macro CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h | 3 +++
 arch/x86/kernel/setup.c      | 5 +----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 6802c59e8252..be18dc7ae51f 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -18,6 +18,9 @@
 
 # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
 
+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN		SZ_16M
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3412c4595efd..da769845597d 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -390,9 +390,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 
 #ifdef CONFIG_KEXEC_CORE
 
-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGN		SZ_16M
-
 /*
  * Keep the crash kernel below this limit.
  *
@@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
 	} else {
 		unsigned long long start;
 
-		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
 						  crash_base + crash_size);
 		if (start != crash_base) {
 			pr_info("crashkernel reservation failed - memory is in use.\n");
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

The lower bounds of crash kernel reservation and crash kernel low
reservation are different, use the consistent value CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index da769845597d..27470479e4a3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
 			return 0;
 	}
 
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
 	if (!low_base) {
 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
 		       (unsigned long)(low_size >> 20));
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

The lower bounds of crash kernel reservation and crash kernel low
reservation are different, use the consistent value CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index da769845597d..27470479e4a3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
 			return 0;
 	}
 
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
 	if (!low_base) {
 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
 		       (unsigned long)(low_size >> 20));
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

The lower bounds of crash kernel reservation and crash kernel low
reservation are different, use the consistent value CRASH_ALIGN.

Suggested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index da769845597d..27470479e4a3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
 			return 0;
 	}
 
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
 	if (!low_base) {
 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
 		       (unsigned long)(low_size >> 20));
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

To make the functions reserve_crashkernel() as generic,
replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 27470479e4a3..086a04235be4 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
 	if (!crash_base) {
 		/*
 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over 4G, also allocates
-		 * 256M extra low memory for DMA buffers and swiotlb.
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
 		 * But the extra memory is not required for all machines.
 		 * So try low memory first and fall back to high memory
 		 * unless "crashkernel=size[KMG],high" is specified.
@@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
 		}
 	}
 
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
 		memblock_free(crash_base, crash_size);
 		return;
 	}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

To make the functions reserve_crashkernel() as generic,
replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 27470479e4a3..086a04235be4 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
 	if (!crash_base) {
 		/*
 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over 4G, also allocates
-		 * 256M extra low memory for DMA buffers and swiotlb.
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
 		 * But the extra memory is not required for all machines.
 		 * So try low memory first and fall back to high memory
 		 * unless "crashkernel=size[KMG],high" is specified.
@@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
 		}
 	}
 
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
 		memblock_free(crash_base, crash_size);
 		return;
 	}
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

To make the functions reserve_crashkernel() as generic,
replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 27470479e4a3..086a04235be4 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
 	if (!crash_base) {
 		/*
 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over 4G, also allocates
-		 * 256M extra low memory for DMA buffers and swiotlb.
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
 		 * But the extra memory is not required for all machines.
 		 * So try low memory first and fall back to high memory
 		 * unless "crashkernel=size[KMG],high" is specified.
@@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
 		}
 	}
 
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
 		memblock_free(crash_base, crash_size);
 		return;
 	}
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch()
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

We will make the functions reserve_crashkernel() as generic, the
xen_pv_domain() check in reserve_crashkernel() is relevant only to
x86, the same as insert_resource() in reserve_crashkernel[_low]().
So move xen_pv_domain() check and insert_resource() to setup_arch()
to keep them in x86.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 086a04235be4..5d676efc32f6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -454,7 +454,6 @@ static int __init reserve_crashkernel_low(void)
 
 	crashk_low_res.start = low_base;
 	crashk_low_res.end   = low_base + low_size - 1;
-	insert_resource(&iomem_resource, &crashk_low_res);
 #endif
 	return 0;
 }
@@ -478,11 +477,6 @@ static void __init reserve_crashkernel(void)
 		high = true;
 	}
 
-	if (xen_pv_domain()) {
-		pr_info("Ignoring crashkernel for a Xen PV domain\n");
-		return;
-	}
-
 	/* 0 means: find the address automatically */
 	if (!crash_base) {
 		/*
@@ -529,7 +523,6 @@ static void __init reserve_crashkernel(void)
 
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
-	insert_resource(&iomem_resource, &crashk_res);
 }
 #else
 static void __init reserve_crashkernel(void)
@@ -1151,7 +1144,17 @@ void __init setup_arch(char **cmdline_p)
 	 * Reserve memory for crash kernel after SRAT is parsed so that it
 	 * won't consume hotpluggable memory.
 	 */
-	reserve_crashkernel();
+	if (xen_pv_domain())
+		pr_info("Ignoring crashkernel for a Xen PV domain\n");
+	else {
+		reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+		if (crashk_res.end > crashk_res.start)
+			insert_resource(&iomem_resource, &crashk_res);
+		if (crashk_low_res.end > crashk_low_res.start)
+			insert_resource(&iomem_resource, &crashk_low_res);
+#endif
+	}
 
 	memblock_find_dma_reserve();
 
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch()
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

We will make the functions reserve_crashkernel() as generic, the
xen_pv_domain() check in reserve_crashkernel() is relevant only to
x86, the same as insert_resource() in reserve_crashkernel[_low]().
So move xen_pv_domain() check and insert_resource() to setup_arch()
to keep them in x86.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 086a04235be4..5d676efc32f6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -454,7 +454,6 @@ static int __init reserve_crashkernel_low(void)
 
 	crashk_low_res.start = low_base;
 	crashk_low_res.end   = low_base + low_size - 1;
-	insert_resource(&iomem_resource, &crashk_low_res);
 #endif
 	return 0;
 }
@@ -478,11 +477,6 @@ static void __init reserve_crashkernel(void)
 		high = true;
 	}
 
-	if (xen_pv_domain()) {
-		pr_info("Ignoring crashkernel for a Xen PV domain\n");
-		return;
-	}
-
 	/* 0 means: find the address automatically */
 	if (!crash_base) {
 		/*
@@ -529,7 +523,6 @@ static void __init reserve_crashkernel(void)
 
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
-	insert_resource(&iomem_resource, &crashk_res);
 }
 #else
 static void __init reserve_crashkernel(void)
@@ -1151,7 +1144,17 @@ void __init setup_arch(char **cmdline_p)
 	 * Reserve memory for crash kernel after SRAT is parsed so that it
 	 * won't consume hotpluggable memory.
 	 */
-	reserve_crashkernel();
+	if (xen_pv_domain())
+		pr_info("Ignoring crashkernel for a Xen PV domain\n");
+	else {
+		reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+		if (crashk_res.end > crashk_res.start)
+			insert_resource(&iomem_resource, &crashk_res);
+		if (crashk_low_res.end > crashk_low_res.start)
+			insert_resource(&iomem_resource, &crashk_low_res);
+#endif
+	}
 
 	memblock_find_dma_reserve();
 
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch()
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

We will make the functions reserve_crashkernel() as generic, the
xen_pv_domain() check in reserve_crashkernel() is relevant only to
x86, the same as insert_resource() in reserve_crashkernel[_low]().
So move xen_pv_domain() check and insert_resource() to setup_arch()
to keep them in x86.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/kernel/setup.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 086a04235be4..5d676efc32f6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -454,7 +454,6 @@ static int __init reserve_crashkernel_low(void)
 
 	crashk_low_res.start = low_base;
 	crashk_low_res.end   = low_base + low_size - 1;
-	insert_resource(&iomem_resource, &crashk_low_res);
 #endif
 	return 0;
 }
@@ -478,11 +477,6 @@ static void __init reserve_crashkernel(void)
 		high = true;
 	}
 
-	if (xen_pv_domain()) {
-		pr_info("Ignoring crashkernel for a Xen PV domain\n");
-		return;
-	}
-
 	/* 0 means: find the address automatically */
 	if (!crash_base) {
 		/*
@@ -529,7 +523,6 @@ static void __init reserve_crashkernel(void)
 
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
-	insert_resource(&iomem_resource, &crashk_res);
 }
 #else
 static void __init reserve_crashkernel(void)
@@ -1151,7 +1144,17 @@ void __init setup_arch(char **cmdline_p)
 	 * Reserve memory for crash kernel after SRAT is parsed so that it
 	 * won't consume hotpluggable memory.
 	 */
-	reserve_crashkernel();
+	if (xen_pv_domain())
+		pr_info("Ignoring crashkernel for a Xen PV domain\n");
+	else {
+		reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+		if (crashk_res.end > crashk_res.start)
+			insert_resource(&iomem_resource, &crashk_res);
+		if (crashk_low_res.end > crashk_low_res.start)
+			insert_resource(&iomem_resource, &crashk_low_res);
+#endif
+	}
 
 	memblock_find_dma_reserve();
 
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 05/11] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

Make the functions reserve_crashkernel[_low]() as generic.
Arm64 will use these to reimplement crashkernel=X.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h |  25 ++++++
 arch/x86/kernel/setup.c      | 143 +------------------------------
 include/linux/crash_core.h   |   3 +
 include/linux/kexec.h        |   2 -
 kernel/crash_core.c          | 159 +++++++++++++++++++++++++++++++++++
 kernel/kexec_core.c          |  17 ----
 6 files changed, 189 insertions(+), 160 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index be18dc7ae51f..2b18f918203e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,27 @@
 /* 16M alignment for crash kernel regions */
 #define CRASH_ALIGN		SZ_16M
 
+/*
+ * Keep the crash kernel below this limit.
+ *
+ * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
+ * due to mapping restrictions.
+ *
+ * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
+ * the upper limit of system RAM in 4-level paging mode. Since the kdump
+ * jump could be from 5-level paging to 4-level paging, the jump will fail if
+ * the kernel is put above 64 TB, and during the 1st kernel bootup there's
+ * no good way to detect the paging mode of the target kernel which will be
+ * loaded for dumping.
+ */
+#ifdef CONFIG_X86_32
+# define CRASH_ADDR_LOW_MAX	SZ_512M
+# define CRASH_ADDR_HIGH_MAX	SZ_512M
+#else
+# define CRASH_ADDR_LOW_MAX	SZ_4G
+# define CRASH_ADDR_HIGH_MAX	SZ_64T
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
@@ -200,6 +221,10 @@ typedef void crash_vmclear_fn(void);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 extern void kdump_nmi_shootdown_cpus(void);
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 5d676efc32f6..d136d6ad3fa8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -38,6 +38,7 @@
 #include <asm/io_apic.h>
 #include <asm/kasan.h>
 #include <asm/kaslr.h>
+#include <asm/kexec.h>
 #include <asm/mce.h>
 #include <asm/mtrr.h>
 #include <asm/realmode.h>
@@ -384,147 +385,7 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 	}
 }
 
-/*
- * --------- Crashkernel reservation ------------------------------
- */
-
-#ifdef CONFIG_KEXEC_CORE
-
-/*
- * Keep the crash kernel below this limit.
- *
- * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
- * due to mapping restrictions.
- *
- * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
- * the upper limit of system RAM in 4-level paging mode. Since the kdump
- * jump could be from 5-level paging to 4-level paging, the jump will fail if
- * the kernel is put above 64 TB, and during the 1st kernel bootup there's
- * no good way to detect the paging mode of the target kernel which will be
- * loaded for dumping.
- */
-#ifdef CONFIG_X86_32
-# define CRASH_ADDR_LOW_MAX	SZ_512M
-# define CRASH_ADDR_HIGH_MAX	SZ_512M
-#else
-# define CRASH_ADDR_LOW_MAX	SZ_4G
-# define CRASH_ADDR_HIGH_MAX	SZ_64T
-#endif
-
-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
-	unsigned long long base, low_base = 0, low_size = 0;
-	unsigned long low_mem_limit;
-	int ret;
-
-	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
-
-	/* crashkernel=Y,low */
-	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
-	if (ret) {
-		/*
-		 * two parts from kernel/dma/swiotlb.c:
-		 * -swiotlb size: user-specified with swiotlb= or default.
-		 *
-		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
-		 * to 8M for other buffers that may need to stay low too. Also
-		 * make sure we allocate enough extra low memory so that we
-		 * don't run out of DMA buffers for 32-bit devices.
-		 */
-		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
-	} else {
-		/* passed with crashkernel=0,low ? */
-		if (!low_size)
-			return 0;
-	}
-
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
-			CRASH_ADDR_LOW_MAX);
-	if (!low_base) {
-		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
-		       (unsigned long)(low_size >> 20));
-		return -ENOMEM;
-	}
-
-	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
-		(unsigned long)(low_size >> 20),
-		(unsigned long)(low_base >> 20),
-		(unsigned long)(low_mem_limit >> 20));
-
-	crashk_low_res.start = low_base;
-	crashk_low_res.end   = low_base + low_size - 1;
-#endif
-	return 0;
-}
-
-static void __init reserve_crashkernel(void)
-{
-	unsigned long long crash_size, crash_base, total_mem;
-	bool high = false;
-	int ret;
-
-	total_mem = memblock_phys_mem_size();
-
-	/* crashkernel=XM */
-	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
-	if (ret != 0 || crash_size <= 0) {
-		/* crashkernel=X,high */
-		ret = parse_crashkernel_high(boot_command_line, total_mem,
-					     &crash_size, &crash_base);
-		if (ret != 0 || crash_size <= 0)
-			return;
-		high = true;
-	}
-
-	/* 0 means: find the address automatically */
-	if (!crash_base) {
-		/*
-		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
-		 * also allocates 256M extra low memory for DMA buffers
-		 * and swiotlb.
-		 * But the extra memory is not required for all machines.
-		 * So try low memory first and fall back to high memory
-		 * unless "crashkernel=size[KMG],high" is specified.
-		 */
-		if (!high)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_LOW_MAX);
-		if (!crash_base)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_HIGH_MAX);
-		if (!crash_base) {
-			pr_info("crashkernel reservation failed - No suitable area found.\n");
-			return;
-		}
-	} else {
-		unsigned long long start;
-
-		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
-						  crash_base + crash_size);
-		if (start != crash_base) {
-			pr_info("crashkernel reservation failed - memory is in use.\n");
-			return;
-		}
-	}
-
-	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
-		memblock_free(crash_base, crash_size);
-		return;
-	}
-
-	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
-		(unsigned long)(crash_size >> 20),
-		(unsigned long)(crash_base >> 20),
-		(unsigned long)(total_mem >> 20));
-
-	crashk_res.start = crash_base;
-	crashk_res.end   = crash_base + crash_size - 1;
-}
-#else
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
 }
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 206bde8308b2..fc0ef33a76f7 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -69,6 +69,9 @@ extern unsigned char *vmcoreinfo_data;
 extern size_t vmcoreinfo_size;
 extern u32 *vmcoreinfo_note;
 
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+
 /* raw contents of kernel .notes section */
 extern const void __start_notes __weak;
 extern const void __stop_notes __weak;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..f301f2f5cfc4 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -337,8 +337,6 @@ extern int kexec_load_disabled;
 
 /* Location of a reserved region to hold the crash kernel.
  */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
 extern note_buf_t __percpu *crash_notes;
 
 /* flag to track if kexec reboot is in progress */
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..a0e790d6ea0f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,6 +7,12 @@
 #include <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>
+
+#ifdef CONFIG_KEXEC_CORE
+#include <asm/kexec.h>
+#endif
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -21,6 +27,22 @@ u32 *vmcoreinfo_note;
 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
 static unsigned char *vmcoreinfo_data_safecopy;
 
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+struct resource crashk_low_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+
 /*
  * parsing the "crashkernel" commandline
  *
@@ -294,6 +316,143 @@ int __init parse_crashkernel_low(char *cmdline,
 				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+#ifdef CONFIG_KEXEC_CORE
+
+#ifdef CONFIG_X86
+static int __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_X86_64
+	unsigned long long base, low_base = 0, low_size = 0;
+	unsigned long low_mem_limit;
+	int ret;
+
+	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
+
+	/* crashkernel=Y,low */
+	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
+	if (ret) {
+		/*
+		 * two parts from kernel/dma/swiotlb.c:
+		 * -swiotlb size: user-specified with swiotlb= or default.
+		 *
+		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
+		 * to 8M for other buffers that may need to stay low too. Also
+		 * make sure we allocate enough extra low memory so that we
+		 * don't run out of DMA buffers for 32-bit devices.
+		 */
+		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
+	} else {
+		/* passed with crashkernel=0,low ? */
+		if (!low_size)
+			return 0;
+	}
+
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
+	if (!low_base) {
+		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
+		       (unsigned long)(low_size >> 20));
+		return -ENOMEM;
+	}
+
+	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
+		(unsigned long)(low_size >> 20),
+		(unsigned long)(low_base >> 20),
+		(unsigned long)(low_mem_limit >> 20));
+
+	crashk_low_res.start = low_base;
+	crashk_low_res.end   = low_base + low_size - 1;
+#endif
+	return 0;
+}
+
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+void __init reserve_crashkernel(void)
+{
+	unsigned long long crash_size, crash_base, total_mem;
+	bool high = false;
+	int ret;
+
+	total_mem = memblock_phys_mem_size();
+
+	/* crashkernel=XM */
+	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
+	if (ret != 0 || crash_size <= 0) {
+		/* crashkernel=X,high */
+		ret = parse_crashkernel_high(boot_command_line, total_mem,
+					     &crash_size, &crash_base);
+		if (ret != 0 || crash_size <= 0)
+			return;
+		high = true;
+	}
+
+	/* 0 means: find the address automatically */
+	if (!crash_base) {
+		/*
+		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
+		 * But the extra memory is not required for all machines.
+		 * So try low memory first and fall back to high memory
+		 * unless "crashkernel=size[KMG],high" is specified.
+		 */
+		if (!high)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_LOW_MAX);
+		if (!crash_base)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_HIGH_MAX);
+		if (!crash_base) {
+			pr_info("crashkernel reservation failed - No suitable area found.\n");
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		unsigned long long start;
+
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
+			pr_warn("cannot reserve crashkernel: base address is not %ldMB aligned\n",
+				(unsigned long)CRASH_ALIGN >> 20);
+			return;
+		}
+
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
+						  crash_base + crash_size);
+		if (start != crash_base) {
+			pr_info("crashkernel reservation failed - memory is in use.\n");
+			return;
+		}
+	}
+
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
+		memblock_free(crash_base, crash_size);
+		return;
+	}
+
+	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
+		(unsigned long)(crash_size >> 20),
+		(unsigned long)(crash_base >> 20),
+		(unsigned long)(total_mem >> 20));
+
+	crashk_res.start = crash_base;
+	crashk_res.end   = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_X86 */
+#endif /* CONFIG_KEXEC_CORE */
+
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
 {
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 4f8efc278aa7..265799e93caf 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,23 +52,6 @@ note_buf_t __percpu *crash_notes;
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
-
-/* Location of the reserved area for the crash kernel */
-struct resource crashk_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-struct resource crashk_low_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-
 int kexec_should_crash(struct task_struct *p)
 {
 	/*
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 05/11] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Make the functions reserve_crashkernel[_low]() as generic.
Arm64 will use these to reimplement crashkernel=X.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h |  25 ++++++
 arch/x86/kernel/setup.c      | 143 +------------------------------
 include/linux/crash_core.h   |   3 +
 include/linux/kexec.h        |   2 -
 kernel/crash_core.c          | 159 +++++++++++++++++++++++++++++++++++
 kernel/kexec_core.c          |  17 ----
 6 files changed, 189 insertions(+), 160 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index be18dc7ae51f..2b18f918203e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,27 @@
 /* 16M alignment for crash kernel regions */
 #define CRASH_ALIGN		SZ_16M
 
+/*
+ * Keep the crash kernel below this limit.
+ *
+ * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
+ * due to mapping restrictions.
+ *
+ * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
+ * the upper limit of system RAM in 4-level paging mode. Since the kdump
+ * jump could be from 5-level paging to 4-level paging, the jump will fail if
+ * the kernel is put above 64 TB, and during the 1st kernel bootup there's
+ * no good way to detect the paging mode of the target kernel which will be
+ * loaded for dumping.
+ */
+#ifdef CONFIG_X86_32
+# define CRASH_ADDR_LOW_MAX	SZ_512M
+# define CRASH_ADDR_HIGH_MAX	SZ_512M
+#else
+# define CRASH_ADDR_LOW_MAX	SZ_4G
+# define CRASH_ADDR_HIGH_MAX	SZ_64T
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
@@ -200,6 +221,10 @@ typedef void crash_vmclear_fn(void);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 extern void kdump_nmi_shootdown_cpus(void);
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 5d676efc32f6..d136d6ad3fa8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -38,6 +38,7 @@
 #include <asm/io_apic.h>
 #include <asm/kasan.h>
 #include <asm/kaslr.h>
+#include <asm/kexec.h>
 #include <asm/mce.h>
 #include <asm/mtrr.h>
 #include <asm/realmode.h>
@@ -384,147 +385,7 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 	}
 }
 
-/*
- * --------- Crashkernel reservation ------------------------------
- */
-
-#ifdef CONFIG_KEXEC_CORE
-
-/*
- * Keep the crash kernel below this limit.
- *
- * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
- * due to mapping restrictions.
- *
- * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
- * the upper limit of system RAM in 4-level paging mode. Since the kdump
- * jump could be from 5-level paging to 4-level paging, the jump will fail if
- * the kernel is put above 64 TB, and during the 1st kernel bootup there's
- * no good way to detect the paging mode of the target kernel which will be
- * loaded for dumping.
- */
-#ifdef CONFIG_X86_32
-# define CRASH_ADDR_LOW_MAX	SZ_512M
-# define CRASH_ADDR_HIGH_MAX	SZ_512M
-#else
-# define CRASH_ADDR_LOW_MAX	SZ_4G
-# define CRASH_ADDR_HIGH_MAX	SZ_64T
-#endif
-
-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
-	unsigned long long base, low_base = 0, low_size = 0;
-	unsigned long low_mem_limit;
-	int ret;
-
-	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
-
-	/* crashkernel=Y,low */
-	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
-	if (ret) {
-		/*
-		 * two parts from kernel/dma/swiotlb.c:
-		 * -swiotlb size: user-specified with swiotlb= or default.
-		 *
-		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
-		 * to 8M for other buffers that may need to stay low too. Also
-		 * make sure we allocate enough extra low memory so that we
-		 * don't run out of DMA buffers for 32-bit devices.
-		 */
-		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
-	} else {
-		/* passed with crashkernel=0,low ? */
-		if (!low_size)
-			return 0;
-	}
-
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
-			CRASH_ADDR_LOW_MAX);
-	if (!low_base) {
-		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
-		       (unsigned long)(low_size >> 20));
-		return -ENOMEM;
-	}
-
-	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
-		(unsigned long)(low_size >> 20),
-		(unsigned long)(low_base >> 20),
-		(unsigned long)(low_mem_limit >> 20));
-
-	crashk_low_res.start = low_base;
-	crashk_low_res.end   = low_base + low_size - 1;
-#endif
-	return 0;
-}
-
-static void __init reserve_crashkernel(void)
-{
-	unsigned long long crash_size, crash_base, total_mem;
-	bool high = false;
-	int ret;
-
-	total_mem = memblock_phys_mem_size();
-
-	/* crashkernel=XM */
-	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
-	if (ret != 0 || crash_size <= 0) {
-		/* crashkernel=X,high */
-		ret = parse_crashkernel_high(boot_command_line, total_mem,
-					     &crash_size, &crash_base);
-		if (ret != 0 || crash_size <= 0)
-			return;
-		high = true;
-	}
-
-	/* 0 means: find the address automatically */
-	if (!crash_base) {
-		/*
-		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
-		 * also allocates 256M extra low memory for DMA buffers
-		 * and swiotlb.
-		 * But the extra memory is not required for all machines.
-		 * So try low memory first and fall back to high memory
-		 * unless "crashkernel=size[KMG],high" is specified.
-		 */
-		if (!high)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_LOW_MAX);
-		if (!crash_base)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_HIGH_MAX);
-		if (!crash_base) {
-			pr_info("crashkernel reservation failed - No suitable area found.\n");
-			return;
-		}
-	} else {
-		unsigned long long start;
-
-		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
-						  crash_base + crash_size);
-		if (start != crash_base) {
-			pr_info("crashkernel reservation failed - memory is in use.\n");
-			return;
-		}
-	}
-
-	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
-		memblock_free(crash_base, crash_size);
-		return;
-	}
-
-	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
-		(unsigned long)(crash_size >> 20),
-		(unsigned long)(crash_base >> 20),
-		(unsigned long)(total_mem >> 20));
-
-	crashk_res.start = crash_base;
-	crashk_res.end   = crash_base + crash_size - 1;
-}
-#else
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
 }
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 206bde8308b2..fc0ef33a76f7 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -69,6 +69,9 @@ extern unsigned char *vmcoreinfo_data;
 extern size_t vmcoreinfo_size;
 extern u32 *vmcoreinfo_note;
 
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+
 /* raw contents of kernel .notes section */
 extern const void __start_notes __weak;
 extern const void __stop_notes __weak;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..f301f2f5cfc4 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -337,8 +337,6 @@ extern int kexec_load_disabled;
 
 /* Location of a reserved region to hold the crash kernel.
  */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
 extern note_buf_t __percpu *crash_notes;
 
 /* flag to track if kexec reboot is in progress */
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..a0e790d6ea0f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,6 +7,12 @@
 #include <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>
+
+#ifdef CONFIG_KEXEC_CORE
+#include <asm/kexec.h>
+#endif
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -21,6 +27,22 @@ u32 *vmcoreinfo_note;
 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
 static unsigned char *vmcoreinfo_data_safecopy;
 
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+struct resource crashk_low_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+
 /*
  * parsing the "crashkernel" commandline
  *
@@ -294,6 +316,143 @@ int __init parse_crashkernel_low(char *cmdline,
 				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+#ifdef CONFIG_KEXEC_CORE
+
+#ifdef CONFIG_X86
+static int __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_X86_64
+	unsigned long long base, low_base = 0, low_size = 0;
+	unsigned long low_mem_limit;
+	int ret;
+
+	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
+
+	/* crashkernel=Y,low */
+	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
+	if (ret) {
+		/*
+		 * two parts from kernel/dma/swiotlb.c:
+		 * -swiotlb size: user-specified with swiotlb= or default.
+		 *
+		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
+		 * to 8M for other buffers that may need to stay low too. Also
+		 * make sure we allocate enough extra low memory so that we
+		 * don't run out of DMA buffers for 32-bit devices.
+		 */
+		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
+	} else {
+		/* passed with crashkernel=0,low ? */
+		if (!low_size)
+			return 0;
+	}
+
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
+	if (!low_base) {
+		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
+		       (unsigned long)(low_size >> 20));
+		return -ENOMEM;
+	}
+
+	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
+		(unsigned long)(low_size >> 20),
+		(unsigned long)(low_base >> 20),
+		(unsigned long)(low_mem_limit >> 20));
+
+	crashk_low_res.start = low_base;
+	crashk_low_res.end   = low_base + low_size - 1;
+#endif
+	return 0;
+}
+
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+void __init reserve_crashkernel(void)
+{
+	unsigned long long crash_size, crash_base, total_mem;
+	bool high = false;
+	int ret;
+
+	total_mem = memblock_phys_mem_size();
+
+	/* crashkernel=XM */
+	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
+	if (ret != 0 || crash_size <= 0) {
+		/* crashkernel=X,high */
+		ret = parse_crashkernel_high(boot_command_line, total_mem,
+					     &crash_size, &crash_base);
+		if (ret != 0 || crash_size <= 0)
+			return;
+		high = true;
+	}
+
+	/* 0 means: find the address automatically */
+	if (!crash_base) {
+		/*
+		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
+		 * But the extra memory is not required for all machines.
+		 * So try low memory first and fall back to high memory
+		 * unless "crashkernel=size[KMG],high" is specified.
+		 */
+		if (!high)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_LOW_MAX);
+		if (!crash_base)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_HIGH_MAX);
+		if (!crash_base) {
+			pr_info("crashkernel reservation failed - No suitable area found.\n");
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		unsigned long long start;
+
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
+			pr_warn("cannot reserve crashkernel: base address is not %ldMB aligned\n",
+				(unsigned long)CRASH_ALIGN >> 20);
+			return;
+		}
+
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
+						  crash_base + crash_size);
+		if (start != crash_base) {
+			pr_info("crashkernel reservation failed - memory is in use.\n");
+			return;
+		}
+	}
+
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
+		memblock_free(crash_base, crash_size);
+		return;
+	}
+
+	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
+		(unsigned long)(crash_size >> 20),
+		(unsigned long)(crash_base >> 20),
+		(unsigned long)(total_mem >> 20));
+
+	crashk_res.start = crash_base;
+	crashk_res.end   = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_X86 */
+#endif /* CONFIG_KEXEC_CORE */
+
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
 {
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 4f8efc278aa7..265799e93caf 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,23 +52,6 @@ note_buf_t __percpu *crash_notes;
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
-
-/* Location of the reserved area for the crash kernel */
-struct resource crashk_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-struct resource crashk_low_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-
 int kexec_should_crash(struct task_struct *p)
 {
 	/*
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 05/11] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Make the functions reserve_crashkernel[_low]() as generic.
Arm64 will use these to reimplement crashkernel=X.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/x86/include/asm/kexec.h |  25 ++++++
 arch/x86/kernel/setup.c      | 143 +------------------------------
 include/linux/crash_core.h   |   3 +
 include/linux/kexec.h        |   2 -
 kernel/crash_core.c          | 159 +++++++++++++++++++++++++++++++++++
 kernel/kexec_core.c          |  17 ----
 6 files changed, 189 insertions(+), 160 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index be18dc7ae51f..2b18f918203e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,27 @@
 /* 16M alignment for crash kernel regions */
 #define CRASH_ALIGN		SZ_16M
 
+/*
+ * Keep the crash kernel below this limit.
+ *
+ * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
+ * due to mapping restrictions.
+ *
+ * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
+ * the upper limit of system RAM in 4-level paging mode. Since the kdump
+ * jump could be from 5-level paging to 4-level paging, the jump will fail if
+ * the kernel is put above 64 TB, and during the 1st kernel bootup there's
+ * no good way to detect the paging mode of the target kernel which will be
+ * loaded for dumping.
+ */
+#ifdef CONFIG_X86_32
+# define CRASH_ADDR_LOW_MAX	SZ_512M
+# define CRASH_ADDR_HIGH_MAX	SZ_512M
+#else
+# define CRASH_ADDR_LOW_MAX	SZ_4G
+# define CRASH_ADDR_HIGH_MAX	SZ_64T
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
@@ -200,6 +221,10 @@ typedef void crash_vmclear_fn(void);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 extern void kdump_nmi_shootdown_cpus(void);
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 5d676efc32f6..d136d6ad3fa8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -38,6 +38,7 @@
 #include <asm/io_apic.h>
 #include <asm/kasan.h>
 #include <asm/kaslr.h>
+#include <asm/kexec.h>
 #include <asm/mce.h>
 #include <asm/mtrr.h>
 #include <asm/realmode.h>
@@ -384,147 +385,7 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 	}
 }
 
-/*
- * --------- Crashkernel reservation ------------------------------
- */
-
-#ifdef CONFIG_KEXEC_CORE
-
-/*
- * Keep the crash kernel below this limit.
- *
- * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
- * due to mapping restrictions.
- *
- * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
- * the upper limit of system RAM in 4-level paging mode. Since the kdump
- * jump could be from 5-level paging to 4-level paging, the jump will fail if
- * the kernel is put above 64 TB, and during the 1st kernel bootup there's
- * no good way to detect the paging mode of the target kernel which will be
- * loaded for dumping.
- */
-#ifdef CONFIG_X86_32
-# define CRASH_ADDR_LOW_MAX	SZ_512M
-# define CRASH_ADDR_HIGH_MAX	SZ_512M
-#else
-# define CRASH_ADDR_LOW_MAX	SZ_4G
-# define CRASH_ADDR_HIGH_MAX	SZ_64T
-#endif
-
-static int __init reserve_crashkernel_low(void)
-{
-#ifdef CONFIG_X86_64
-	unsigned long long base, low_base = 0, low_size = 0;
-	unsigned long low_mem_limit;
-	int ret;
-
-	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
-
-	/* crashkernel=Y,low */
-	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
-	if (ret) {
-		/*
-		 * two parts from kernel/dma/swiotlb.c:
-		 * -swiotlb size: user-specified with swiotlb= or default.
-		 *
-		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
-		 * to 8M for other buffers that may need to stay low too. Also
-		 * make sure we allocate enough extra low memory so that we
-		 * don't run out of DMA buffers for 32-bit devices.
-		 */
-		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
-	} else {
-		/* passed with crashkernel=0,low ? */
-		if (!low_size)
-			return 0;
-	}
-
-	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
-			CRASH_ADDR_LOW_MAX);
-	if (!low_base) {
-		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
-		       (unsigned long)(low_size >> 20));
-		return -ENOMEM;
-	}
-
-	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
-		(unsigned long)(low_size >> 20),
-		(unsigned long)(low_base >> 20),
-		(unsigned long)(low_mem_limit >> 20));
-
-	crashk_low_res.start = low_base;
-	crashk_low_res.end   = low_base + low_size - 1;
-#endif
-	return 0;
-}
-
-static void __init reserve_crashkernel(void)
-{
-	unsigned long long crash_size, crash_base, total_mem;
-	bool high = false;
-	int ret;
-
-	total_mem = memblock_phys_mem_size();
-
-	/* crashkernel=XM */
-	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
-	if (ret != 0 || crash_size <= 0) {
-		/* crashkernel=X,high */
-		ret = parse_crashkernel_high(boot_command_line, total_mem,
-					     &crash_size, &crash_base);
-		if (ret != 0 || crash_size <= 0)
-			return;
-		high = true;
-	}
-
-	/* 0 means: find the address automatically */
-	if (!crash_base) {
-		/*
-		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
-		 * also allocates 256M extra low memory for DMA buffers
-		 * and swiotlb.
-		 * But the extra memory is not required for all machines.
-		 * So try low memory first and fall back to high memory
-		 * unless "crashkernel=size[KMG],high" is specified.
-		 */
-		if (!high)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_LOW_MAX);
-		if (!crash_base)
-			crash_base = memblock_phys_alloc_range(crash_size,
-						CRASH_ALIGN, CRASH_ALIGN,
-						CRASH_ADDR_HIGH_MAX);
-		if (!crash_base) {
-			pr_info("crashkernel reservation failed - No suitable area found.\n");
-			return;
-		}
-	} else {
-		unsigned long long start;
-
-		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
-						  crash_base + crash_size);
-		if (start != crash_base) {
-			pr_info("crashkernel reservation failed - memory is in use.\n");
-			return;
-		}
-	}
-
-	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
-		memblock_free(crash_base, crash_size);
-		return;
-	}
-
-	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
-		(unsigned long)(crash_size >> 20),
-		(unsigned long)(crash_base >> 20),
-		(unsigned long)(total_mem >> 20));
-
-	crashk_res.start = crash_base;
-	crashk_res.end   = crash_base + crash_size - 1;
-}
-#else
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
 }
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 206bde8308b2..fc0ef33a76f7 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -69,6 +69,9 @@ extern unsigned char *vmcoreinfo_data;
 extern size_t vmcoreinfo_size;
 extern u32 *vmcoreinfo_note;
 
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+
 /* raw contents of kernel .notes section */
 extern const void __start_notes __weak;
 extern const void __stop_notes __weak;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 9e93bef52968..f301f2f5cfc4 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -337,8 +337,6 @@ extern int kexec_load_disabled;
 
 /* Location of a reserved region to hold the crash kernel.
  */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
 extern note_buf_t __percpu *crash_notes;
 
 /* flag to track if kexec reboot is in progress */
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 825284baaf46..a0e790d6ea0f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -7,6 +7,12 @@
 #include <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/swiotlb.h>
+
+#ifdef CONFIG_KEXEC_CORE
+#include <asm/kexec.h>
+#endif
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -21,6 +27,22 @@ u32 *vmcoreinfo_note;
 /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
 static unsigned char *vmcoreinfo_data_safecopy;
 
+/* Location of the reserved area for the crash kernel */
+struct resource crashk_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+struct resource crashk_low_res = {
+	.name  = "Crash kernel",
+	.start = 0,
+	.end   = 0,
+	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
+	.desc  = IORES_DESC_CRASH_KERNEL
+};
+
 /*
  * parsing the "crashkernel" commandline
  *
@@ -294,6 +316,143 @@ int __init parse_crashkernel_low(char *cmdline,
 				"crashkernel=", suffix_tbl[SUFFIX_LOW]);
 }
 
+/*
+ * --------- Crashkernel reservation ------------------------------
+ */
+
+#ifdef CONFIG_KEXEC_CORE
+
+#ifdef CONFIG_X86
+static int __init reserve_crashkernel_low(void)
+{
+#ifdef CONFIG_X86_64
+	unsigned long long base, low_base = 0, low_size = 0;
+	unsigned long low_mem_limit;
+	int ret;
+
+	low_mem_limit = min(memblock_phys_mem_size(), CRASH_ADDR_LOW_MAX);
+
+	/* crashkernel=Y,low */
+	ret = parse_crashkernel_low(boot_command_line, low_mem_limit, &low_size, &base);
+	if (ret) {
+		/*
+		 * two parts from kernel/dma/swiotlb.c:
+		 * -swiotlb size: user-specified with swiotlb= or default.
+		 *
+		 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
+		 * to 8M for other buffers that may need to stay low too. Also
+		 * make sure we allocate enough extra low memory so that we
+		 * don't run out of DMA buffers for 32-bit devices.
+		 */
+		low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
+	} else {
+		/* passed with crashkernel=0,low ? */
+		if (!low_size)
+			return 0;
+	}
+
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
+			CRASH_ADDR_LOW_MAX);
+	if (!low_base) {
+		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
+		       (unsigned long)(low_size >> 20));
+		return -ENOMEM;
+	}
+
+	pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (low RAM limit: %ldMB)\n",
+		(unsigned long)(low_size >> 20),
+		(unsigned long)(low_base >> 20),
+		(unsigned long)(low_mem_limit >> 20));
+
+	crashk_low_res.start = low_base;
+	crashk_low_res.end   = low_base + low_size - 1;
+#endif
+	return 0;
+}
+
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+void __init reserve_crashkernel(void)
+{
+	unsigned long long crash_size, crash_base, total_mem;
+	bool high = false;
+	int ret;
+
+	total_mem = memblock_phys_mem_size();
+
+	/* crashkernel=XM */
+	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
+	if (ret != 0 || crash_size <= 0) {
+		/* crashkernel=X,high */
+		ret = parse_crashkernel_high(boot_command_line, total_mem,
+					     &crash_size, &crash_base);
+		if (ret != 0 || crash_size <= 0)
+			return;
+		high = true;
+	}
+
+	/* 0 means: find the address automatically */
+	if (!crash_base) {
+		/*
+		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
+		 * But the extra memory is not required for all machines.
+		 * So try low memory first and fall back to high memory
+		 * unless "crashkernel=size[KMG],high" is specified.
+		 */
+		if (!high)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_LOW_MAX);
+		if (!crash_base)
+			crash_base = memblock_phys_alloc_range(crash_size,
+						CRASH_ALIGN, CRASH_ALIGN,
+						CRASH_ADDR_HIGH_MAX);
+		if (!crash_base) {
+			pr_info("crashkernel reservation failed - No suitable area found.\n");
+			return;
+		}
+	} else {
+		/* User specifies base address explicitly. */
+		unsigned long long start;
+
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
+			pr_warn("cannot reserve crashkernel: base address is not %ldMB aligned\n",
+				(unsigned long)CRASH_ALIGN >> 20);
+			return;
+		}
+
+		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
+						  crash_base + crash_size);
+		if (start != crash_base) {
+			pr_info("crashkernel reservation failed - memory is in use.\n");
+			return;
+		}
+	}
+
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
+		memblock_free(crash_base, crash_size);
+		return;
+	}
+
+	pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
+		(unsigned long)(crash_size >> 20),
+		(unsigned long)(crash_base >> 20),
+		(unsigned long)(total_mem >> 20));
+
+	crashk_res.start = crash_base;
+	crashk_res.end   = crash_base + crash_size - 1;
+}
+#endif /* CONFIG_X86 */
+#endif /* CONFIG_KEXEC_CORE */
+
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
 {
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 4f8efc278aa7..265799e93caf 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,23 +52,6 @@ note_buf_t __percpu *crash_notes;
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
-
-/* Location of the reserved area for the crash kernel */
-struct resource crashk_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-struct resource crashk_low_res = {
-	.name  = "Crash kernel",
-	.start = 0,
-	.end   = 0,
-	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
-	.desc  = IORES_DESC_CRASH_KERNEL
-};
-
 int kexec_should_crash(struct task_struct *p)
 {
 	/*
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, kernel test robot

Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
to arch/x86/include/asm/elf.h to fix the following compiling warning:

make ARCH=i386
In file included from arch/x86/kernel/setup.c:39:0:
./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
 # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)

In file included from arch/x86/kernel/setup.c:9:0:
./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
 #define vmcore_elf_check_arch_cross(x) 0

The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
reserve_crashkernel[_low]() into crash_core.c") triggered the issue.

Suggested by Mike, simply move vmcore_elf_check_arch_cross from
arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
the warning.

Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/x86/include/asm/elf.h   | 3 +++
 arch/x86/include/asm/kexec.h | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 66bdfe838d61..5333777cc758 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
 
 #define elf_check_arch(x)	elf_check_arch_ia32(x)
 
+/* We can also handle crash dumps from 64 bit kernel. */
+# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
+
 /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
    contains a pointer to a function which might be registered using `atexit'.
    This provides a mean for the dynamic linker to call DT_FINI functions for
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 2b18f918203e..6fcae01a9cca 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -72,9 +72,6 @@ struct kimage;
 
 /* The native architecture */
 # define KEXEC_ARCH KEXEC_ARCH_386
-
-/* We can also handle crash dumps from 64 bit kernel. */
-# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
 #else
 /* Maximum physical address we can use pages from */
 # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, kernel test robot, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
to arch/x86/include/asm/elf.h to fix the following compiling warning:

make ARCH=i386
In file included from arch/x86/kernel/setup.c:39:0:
./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
 # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)

In file included from arch/x86/kernel/setup.c:9:0:
./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
 #define vmcore_elf_check_arch_cross(x) 0

The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
reserve_crashkernel[_low]() into crash_core.c") triggered the issue.

Suggested by Mike, simply move vmcore_elf_check_arch_cross from
arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
the warning.

Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/x86/include/asm/elf.h   | 3 +++
 arch/x86/include/asm/kexec.h | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 66bdfe838d61..5333777cc758 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
 
 #define elf_check_arch(x)	elf_check_arch_ia32(x)
 
+/* We can also handle crash dumps from 64 bit kernel. */
+# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
+
 /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
    contains a pointer to a function which might be registered using `atexit'.
    This provides a mean for the dynamic linker to call DT_FINI functions for
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 2b18f918203e..6fcae01a9cca 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -72,9 +72,6 @@ struct kimage;
 
 /* The native architecture */
 # define KEXEC_ARCH KEXEC_ARCH_386
-
-/* We can also handle crash dumps from 64 bit kernel. */
-# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
 #else
 /* Maximum physical address we can use pages from */
 # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, kernel test robot, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
to arch/x86/include/asm/elf.h to fix the following compiling warning:

make ARCH=i386
In file included from arch/x86/kernel/setup.c:39:0:
./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
 # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)

In file included from arch/x86/kernel/setup.c:9:0:
./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
 #define vmcore_elf_check_arch_cross(x) 0

The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
reserve_crashkernel[_low]() into crash_core.c") triggered the issue.

Suggested by Mike, simply move vmcore_elf_check_arch_cross from
arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
the warning.

Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/x86/include/asm/elf.h   | 3 +++
 arch/x86/include/asm/kexec.h | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 66bdfe838d61..5333777cc758 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
 
 #define elf_check_arch(x)	elf_check_arch_ia32(x)
 
+/* We can also handle crash dumps from 64 bit kernel. */
+# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
+
 /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
    contains a pointer to a function which might be registered using `atexit'.
    This provides a mean for the dynamic linker to call DT_FINI functions for
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 2b18f918203e..6fcae01a9cca 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -72,9 +72,6 @@ struct kimage;
 
 /* The native architecture */
 # define KEXEC_ARCH KEXEC_ARCH_386
-
-/* We can also handle crash dumps from 64 bit kernel. */
-# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
 #else
 /* Maximum physical address we can use pages from */
 # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
upper bound of high crash memory, use macroes instead.

Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
of crash kernel reservation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h | 6 ++++++
 arch/arm64/mm/init.c           | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..3f6ecae0bc68 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -25,6 +25,12 @@
 
 #define KEXEC_ARCH KEXEC_ARCH_AARCH64
 
+/* 2M alignment for crash kernel regions */
+#define CRASH_ALIGN	SZ_2M
+
+#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
+#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
+
 #ifndef __ASSEMBLY__
 
 /**
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 709d98fea90c..912f64f505f7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
 
 	if (crash_base == 0) {
 		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
-				crash_size, SZ_2M);
+		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
+				crash_size, CRASH_ALIGN);
 		if (crash_base == 0) {
 			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 				crash_size);
@@ -103,7 +103,7 @@ static void __init reserve_crashkernel(void)
 			return;
 		}
 
-		if (!IS_ALIGNED(crash_base, SZ_2M)) {
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
 			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
 			return;
 		}
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
upper bound of high crash memory, use macroes instead.

Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
of crash kernel reservation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h | 6 ++++++
 arch/arm64/mm/init.c           | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..3f6ecae0bc68 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -25,6 +25,12 @@
 
 #define KEXEC_ARCH KEXEC_ARCH_AARCH64
 
+/* 2M alignment for crash kernel regions */
+#define CRASH_ALIGN	SZ_2M
+
+#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
+#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
+
 #ifndef __ASSEMBLY__
 
 /**
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 709d98fea90c..912f64f505f7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
 
 	if (crash_base == 0) {
 		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
-				crash_size, SZ_2M);
+		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
+				crash_size, CRASH_ALIGN);
 		if (crash_base == 0) {
 			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 				crash_size);
@@ -103,7 +103,7 @@ static void __init reserve_crashkernel(void)
 			return;
 		}
 
-		if (!IS_ALIGNED(crash_base, SZ_2M)) {
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
 			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
 			return;
 		}
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
upper bound of high crash memory, use macroes instead.

Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
of crash kernel reservation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h | 6 ++++++
 arch/arm64/mm/init.c           | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..3f6ecae0bc68 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -25,6 +25,12 @@
 
 #define KEXEC_ARCH KEXEC_ARCH_AARCH64
 
+/* 2M alignment for crash kernel regions */
+#define CRASH_ALIGN	SZ_2M
+
+#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
+#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
+
 #ifndef __ASSEMBLY__
 
 /**
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 709d98fea90c..912f64f505f7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
 
 	if (crash_base == 0) {
 		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
-				crash_size, SZ_2M);
+		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
+				crash_size, CRASH_ALIGN);
 		if (crash_base == 0) {
 			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
 				crash_size);
@@ -103,7 +103,7 @@ static void __init reserve_crashkernel(void)
 			return;
 		}
 
-		if (!IS_ALIGNED(crash_base, SZ_2M)) {
+		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
 			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
 			return;
 		}
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X and
introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
in DMA zone, and fall back to high allocation if it fails.
We can also use "crashkernel=X,high" to select a region above DMA zone,
which also tries to allocate at least 256M in DMA zone automatically.
"crashkernel=Y,low" can be used to allocate specified size low memory.

Another minor change, there may be two regions reserved for crash
dump kernel, in order to distinct from the high region and make no
effect to the use of existing kexec-tools, rename the low region as
"Crash kernel (low)".

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h |  4 ++
 arch/arm64/kernel/setup.c      | 13 ++++++-
 arch/arm64/mm/init.c           | 68 ++++++----------------------------
 kernel/crash_core.c            |  6 +--
 4 files changed, 30 insertions(+), 61 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 3f6ecae0bc68..f0caed0cb5e1 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #ifdef CONFIG_KEXEC_FILE
 #define ARCH_HAS_KIMAGE_ARCH
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index c18aacde8bb0..69c592c546de 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 #ifdef CONFIG_KEXEC_CORE
-		/* Userspace will find "Crash kernel" region in /proc/iomem. */
+		/*
+		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
+		 * region in /proc/iomem.
+		 * In order to distinct from the high region and make no effect
+		 * to the use of existing kexec-tools, rename the low region as
+		 * "Crash kernel (low)".
+		 */
+		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
+				crashk_low_res.end <= res->end) {
+			crashk_low_res.name = "Crash kernel (low)";
+			request_resource(res, &crashk_low_res);
+		}
 		if (crashk_res.end && crashk_res.start >= res->start &&
 		    crashk_res.end <= res->end)
 			request_resource(res, &crashk_res);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 912f64f505f7..d20f5c444ebf 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,6 +35,7 @@
 #include <asm/fixmap.h>
 #include <asm/kasan.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kexec.h>
 #include <asm/memory.h>
 #include <asm/numa.h>
 #include <asm/sections.h>
@@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
  */
 phys_addr_t arm64_dma_phys_limit __ro_after_init;
 
-#ifdef CONFIG_KEXEC_CORE
-/*
- * reserve_crashkernel() - reserves memory for crash kernel
- *
- * This function reserves memory area given in "crashkernel=" kernel command
- * line parameter. The memory reserved is used by dump capture kernel when
- * primary kernel is crashing.
- */
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
-	unsigned long long crash_base, crash_size;
-	int ret;
-
-	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
-				&crash_size, &crash_base);
-	/* no crashkernel= or invalid value specified */
-	if (ret || !crash_size)
-		return;
-
-	crash_size = PAGE_ALIGN(crash_size);
-
-	if (crash_base == 0) {
-		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
-				crash_size, CRASH_ALIGN);
-		if (crash_base == 0) {
-			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
-				crash_size);
-			return;
-		}
-	} else {
-		/* User specifies base address explicitly. */
-		if (!memblock_is_region_memory(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region is not memory\n");
-			return;
-		}
-
-		if (memblock_is_region_reserved(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
-			return;
-		}
-
-		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
-			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
-			return;
-		}
-	}
-	memblock_reserve(crash_base, crash_size);
-
-	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
-		crash_base, crash_base + crash_size, crash_size >> 20);
-
-	crashk_res.start = crash_base;
-	crashk_res.end = crash_base + crash_size - 1;
 }
-#else
-static void __init reserve_crashkernel(void)
-{
-}
-#endif /* CONFIG_KEXEC_CORE */
+#endif
 
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
@@ -446,6 +392,14 @@ void __init bootmem_init(void)
 	 * reserved, so do it here.
 	 */
 	reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+	/*
+	 * The low region is intended to be used for crash dump kernel devices,
+	 * just mark the low region as "nomap" simply.
+	 */
+	if (crashk_low_res.end)
+		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
+#endif
 
 	memblock_dump_all();
 }
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a0e790d6ea0f..8479be270c0b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -322,10 +322,10 @@ int __init parse_crashkernel_low(char *cmdline,
 
 #ifdef CONFIG_KEXEC_CORE
 
-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
 static int __init reserve_crashkernel_low(void)
 {
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_64BIT
 	unsigned long long base, low_base = 0, low_size = 0;
 	unsigned long low_mem_limit;
 	int ret;
@@ -450,7 +450,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif /* CONFIG_X86 */
+#endif
 #endif /* CONFIG_KEXEC_CORE */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X and
introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
in DMA zone, and fall back to high allocation if it fails.
We can also use "crashkernel=X,high" to select a region above DMA zone,
which also tries to allocate at least 256M in DMA zone automatically.
"crashkernel=Y,low" can be used to allocate specified size low memory.

Another minor change, there may be two regions reserved for crash
dump kernel, in order to distinct from the high region and make no
effect to the use of existing kexec-tools, rename the low region as
"Crash kernel (low)".

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h |  4 ++
 arch/arm64/kernel/setup.c      | 13 ++++++-
 arch/arm64/mm/init.c           | 68 ++++++----------------------------
 kernel/crash_core.c            |  6 +--
 4 files changed, 30 insertions(+), 61 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 3f6ecae0bc68..f0caed0cb5e1 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #ifdef CONFIG_KEXEC_FILE
 #define ARCH_HAS_KIMAGE_ARCH
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index c18aacde8bb0..69c592c546de 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 #ifdef CONFIG_KEXEC_CORE
-		/* Userspace will find "Crash kernel" region in /proc/iomem. */
+		/*
+		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
+		 * region in /proc/iomem.
+		 * In order to distinct from the high region and make no effect
+		 * to the use of existing kexec-tools, rename the low region as
+		 * "Crash kernel (low)".
+		 */
+		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
+				crashk_low_res.end <= res->end) {
+			crashk_low_res.name = "Crash kernel (low)";
+			request_resource(res, &crashk_low_res);
+		}
 		if (crashk_res.end && crashk_res.start >= res->start &&
 		    crashk_res.end <= res->end)
 			request_resource(res, &crashk_res);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 912f64f505f7..d20f5c444ebf 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,6 +35,7 @@
 #include <asm/fixmap.h>
 #include <asm/kasan.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kexec.h>
 #include <asm/memory.h>
 #include <asm/numa.h>
 #include <asm/sections.h>
@@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
  */
 phys_addr_t arm64_dma_phys_limit __ro_after_init;
 
-#ifdef CONFIG_KEXEC_CORE
-/*
- * reserve_crashkernel() - reserves memory for crash kernel
- *
- * This function reserves memory area given in "crashkernel=" kernel command
- * line parameter. The memory reserved is used by dump capture kernel when
- * primary kernel is crashing.
- */
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
-	unsigned long long crash_base, crash_size;
-	int ret;
-
-	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
-				&crash_size, &crash_base);
-	/* no crashkernel= or invalid value specified */
-	if (ret || !crash_size)
-		return;
-
-	crash_size = PAGE_ALIGN(crash_size);
-
-	if (crash_base == 0) {
-		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
-				crash_size, CRASH_ALIGN);
-		if (crash_base == 0) {
-			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
-				crash_size);
-			return;
-		}
-	} else {
-		/* User specifies base address explicitly. */
-		if (!memblock_is_region_memory(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region is not memory\n");
-			return;
-		}
-
-		if (memblock_is_region_reserved(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
-			return;
-		}
-
-		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
-			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
-			return;
-		}
-	}
-	memblock_reserve(crash_base, crash_size);
-
-	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
-		crash_base, crash_base + crash_size, crash_size >> 20);
-
-	crashk_res.start = crash_base;
-	crashk_res.end = crash_base + crash_size - 1;
 }
-#else
-static void __init reserve_crashkernel(void)
-{
-}
-#endif /* CONFIG_KEXEC_CORE */
+#endif
 
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
@@ -446,6 +392,14 @@ void __init bootmem_init(void)
 	 * reserved, so do it here.
 	 */
 	reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+	/*
+	 * The low region is intended to be used for crash dump kernel devices,
+	 * just mark the low region as "nomap" simply.
+	 */
+	if (crashk_low_res.end)
+		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
+#endif
 
 	memblock_dump_all();
 }
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a0e790d6ea0f..8479be270c0b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -322,10 +322,10 @@ int __init parse_crashkernel_low(char *cmdline,
 
 #ifdef CONFIG_KEXEC_CORE
 
-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
 static int __init reserve_crashkernel_low(void)
 {
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_64BIT
 	unsigned long long base, low_base = 0, low_size = 0;
 	unsigned long low_mem_limit;
 	int ret;
@@ -450,7 +450,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif /* CONFIG_X86 */
+#endif
 #endif /* CONFIG_KEXEC_CORE */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which
will fail when there is no enough low memory.
2. If reserving crashkernel above 4G, in this case, crash dump
kernel will boot failure because there is no low memory available
for allocation.

To solve these issues, change the behavior of crashkernel=X and
introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
in DMA zone, and fall back to high allocation if it fails.
We can also use "crashkernel=X,high" to select a region above DMA zone,
which also tries to allocate at least 256M in DMA zone automatically.
"crashkernel=Y,low" can be used to allocate specified size low memory.

Another minor change, there may be two regions reserved for crash
dump kernel, in order to distinct from the high region and make no
effect to the use of existing kexec-tools, rename the low region as
"Crash kernel (low)".

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/include/asm/kexec.h |  4 ++
 arch/arm64/kernel/setup.c      | 13 ++++++-
 arch/arm64/mm/init.c           | 68 ++++++----------------------------
 kernel/crash_core.c            |  6 +--
 4 files changed, 30 insertions(+), 61 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 3f6ecae0bc68..f0caed0cb5e1 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+extern void __init reserve_crashkernel(void);
+#endif
+
 #ifdef CONFIG_KEXEC_FILE
 #define ARCH_HAS_KIMAGE_ARCH
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index c18aacde8bb0..69c592c546de 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
 		    kernel_data.end <= res->end)
 			request_resource(res, &kernel_data);
 #ifdef CONFIG_KEXEC_CORE
-		/* Userspace will find "Crash kernel" region in /proc/iomem. */
+		/*
+		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
+		 * region in /proc/iomem.
+		 * In order to distinct from the high region and make no effect
+		 * to the use of existing kexec-tools, rename the low region as
+		 * "Crash kernel (low)".
+		 */
+		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
+				crashk_low_res.end <= res->end) {
+			crashk_low_res.name = "Crash kernel (low)";
+			request_resource(res, &crashk_low_res);
+		}
 		if (crashk_res.end && crashk_res.start >= res->start &&
 		    crashk_res.end <= res->end)
 			request_resource(res, &crashk_res);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 912f64f505f7..d20f5c444ebf 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -35,6 +35,7 @@
 #include <asm/fixmap.h>
 #include <asm/kasan.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kexec.h>
 #include <asm/memory.h>
 #include <asm/numa.h>
 #include <asm/sections.h>
@@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
  */
 phys_addr_t arm64_dma_phys_limit __ro_after_init;
 
-#ifdef CONFIG_KEXEC_CORE
-/*
- * reserve_crashkernel() - reserves memory for crash kernel
- *
- * This function reserves memory area given in "crashkernel=" kernel command
- * line parameter. The memory reserved is used by dump capture kernel when
- * primary kernel is crashing.
- */
+#ifndef CONFIG_KEXEC_CORE
 static void __init reserve_crashkernel(void)
 {
-	unsigned long long crash_base, crash_size;
-	int ret;
-
-	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
-				&crash_size, &crash_base);
-	/* no crashkernel= or invalid value specified */
-	if (ret || !crash_size)
-		return;
-
-	crash_size = PAGE_ALIGN(crash_size);
-
-	if (crash_base == 0) {
-		/* Current arm64 boot protocol requires 2MB alignment */
-		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
-				crash_size, CRASH_ALIGN);
-		if (crash_base == 0) {
-			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
-				crash_size);
-			return;
-		}
-	} else {
-		/* User specifies base address explicitly. */
-		if (!memblock_is_region_memory(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region is not memory\n");
-			return;
-		}
-
-		if (memblock_is_region_reserved(crash_base, crash_size)) {
-			pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
-			return;
-		}
-
-		if (!IS_ALIGNED(crash_base, CRASH_ALIGN)) {
-			pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
-			return;
-		}
-	}
-	memblock_reserve(crash_base, crash_size);
-
-	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
-		crash_base, crash_base + crash_size, crash_size >> 20);
-
-	crashk_res.start = crash_base;
-	crashk_res.end = crash_base + crash_size - 1;
 }
-#else
-static void __init reserve_crashkernel(void)
-{
-}
-#endif /* CONFIG_KEXEC_CORE */
+#endif
 
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
@@ -446,6 +392,14 @@ void __init bootmem_init(void)
 	 * reserved, so do it here.
 	 */
 	reserve_crashkernel();
+#ifdef CONFIG_KEXEC_CORE
+	/*
+	 * The low region is intended to be used for crash dump kernel devices,
+	 * just mark the low region as "nomap" simply.
+	 */
+	if (crashk_low_res.end)
+		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
+#endif
 
 	memblock_dump_all();
 }
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a0e790d6ea0f..8479be270c0b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -322,10 +322,10 @@ int __init parse_crashkernel_low(char *cmdline,
 
 #ifdef CONFIG_KEXEC_CORE
 
-#ifdef CONFIG_X86
+#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
 static int __init reserve_crashkernel_low(void)
 {
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_64BIT
 	unsigned long long base, low_base = 0, low_size = 0;
 	unsigned long low_mem_limit;
 	int ret;
@@ -450,7 +450,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif /* CONFIG_X86 */
+#endif
 #endif /* CONFIG_KEXEC_CORE */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec

We make the functions reserve_crashkernel[_low]() as generic for
x86 and arm64. Since reserve_crashkernel[_low]() implementations
are quite similar on other architectures as well, we can have more
users of this later.

So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
select this by X86 and ARM64.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/Kconfig        | 3 +++
 arch/arm64/Kconfig  | 1 +
 arch/x86/Kconfig    | 2 ++
 kernel/crash_core.c | 7 ++-----
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..0ca1ff5bb157 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -24,6 +24,9 @@ config KEXEC_ELF
 config HAVE_IMA_KEXEC
 	bool
 
+config ARCH_WANT_RESERVE_CRASH_KERNEL
+	bool
+
 config SET_FS
 	bool
 
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..09365c7ff469 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -82,6 +82,7 @@ config ARM64
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..e6926fcb4a40 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86_32
 	depends on !64BIT
 	# Options that are inherently 32-bit kernel only:
 	select ARCH_WANT_IPC_PARSE_VERSION
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select CLKSRC_I8253
 	select CLONE_BACKWARDS
 	select GENERIC_VDSO_32
@@ -28,6 +29,7 @@ config X86_64
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 8479be270c0b..2c5783985db5 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
  * --------- Crashkernel reservation ------------------------------
  */
 
-#ifdef CONFIG_KEXEC_CORE
-
-#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
+#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
 static int __init reserve_crashkernel_low(void)
 {
 #ifdef CONFIG_64BIT
@@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif
-#endif /* CONFIG_KEXEC_CORE */
+#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, chenzhou10, linux-doc, kexec,
	linux-kernel, robh+dt, horms, james.morse, huawei.libin,
	guohanjun, linux-arm-kernel

We make the functions reserve_crashkernel[_low]() as generic for
x86 and arm64. Since reserve_crashkernel[_low]() implementations
are quite similar on other architectures as well, we can have more
users of this later.

So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
select this by X86 and ARM64.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/Kconfig        | 3 +++
 arch/arm64/Kconfig  | 1 +
 arch/x86/Kconfig    | 2 ++
 kernel/crash_core.c | 7 ++-----
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..0ca1ff5bb157 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -24,6 +24,9 @@ config KEXEC_ELF
 config HAVE_IMA_KEXEC
 	bool
 
+config ARCH_WANT_RESERVE_CRASH_KERNEL
+	bool
+
 config SET_FS
 	bool
 
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..09365c7ff469 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -82,6 +82,7 @@ config ARM64
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..e6926fcb4a40 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86_32
 	depends on !64BIT
 	# Options that are inherently 32-bit kernel only:
 	select ARCH_WANT_IPC_PARSE_VERSION
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select CLKSRC_I8253
 	select CLONE_BACKWARDS
 	select GENERIC_VDSO_32
@@ -28,6 +29,7 @@ config X86_64
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 8479be270c0b..2c5783985db5 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
  * --------- Crashkernel reservation ------------------------------
  */
 
-#ifdef CONFIG_KEXEC_CORE
-
-#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
+#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
 static int __init reserve_crashkernel_low(void)
 {
 #ifdef CONFIG_64BIT
@@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif
-#endif /* CONFIG_KEXEC_CORE */
+#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, chenzhou10, linux-doc, kexec,
	linux-kernel, robh+dt, horms, james.morse, huawei.libin,
	guohanjun, linux-arm-kernel

We make the functions reserve_crashkernel[_low]() as generic for
x86 and arm64. Since reserve_crashkernel[_low]() implementations
are quite similar on other architectures as well, we can have more
users of this later.

So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
select this by X86 and ARM64.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/Kconfig        | 3 +++
 arch/arm64/Kconfig  | 1 +
 arch/x86/Kconfig    | 2 ++
 kernel/crash_core.c | 7 ++-----
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..0ca1ff5bb157 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -24,6 +24,9 @@ config KEXEC_ELF
 config HAVE_IMA_KEXEC
 	bool
 
+config ARCH_WANT_RESERVE_CRASH_KERNEL
+	bool
+
 config SET_FS
 	bool
 
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..09365c7ff469 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -82,6 +82,7 @@ config ARM64
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..e6926fcb4a40 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86_32
 	depends on !64BIT
 	# Options that are inherently 32-bit kernel only:
 	select ARCH_WANT_IPC_PARSE_VERSION
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select CLKSRC_I8253
 	select CLONE_BACKWARDS
 	select GENERIC_VDSO_32
@@ -28,6 +29,7 @@ config X86_64
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 8479be270c0b..2c5783985db5 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
  * --------- Crashkernel reservation ------------------------------
  */
 
-#ifdef CONFIG_KEXEC_CORE
-
-#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
+#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
 static int __init reserve_crashkernel_low(void)
 {
 #ifdef CONFIG_64BIT
@@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif
-#endif /* CONFIG_KEXEC_CORE */
+#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux,usable-memory-range
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices and never mapped by the first kernel.
This memory range is advertised to crash dump kernel via DT property
under /chosen,
	linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]>

We reused the DT property linux,usable-memory-range and made the low
memory region as the second range "BASE2 SIZE2", which keeps compatibility
with existing user-space and older kdump kernels.

Crash dump kernel reads this property at boot time and call memblock_add()
to add the low memory region after memblock_cap_memory_range() has been
called.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/mm/init.c | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d20f5c444ebf..180a25b67f55 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -68,6 +68,15 @@ static void __init reserve_crashkernel(void)
 }
 #endif
 
+/*
+ * The main usage of linux,usable-memory-range is for crash dump kernel.
+ * Originally, the number of usable-memory regions is one. Now there may
+ * be two regions, low region and high region.
+ * To make compatibility with existing user-space and older kdump, the low
+ * region is always the last range of linux,usable-memory-range if exist.
+ */
+#define MAX_USABLE_RANGES	2
+
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
 		const char *uname, int depth, void *data)
@@ -201,9 +210,9 @@ early_param("mem", early_mem);
 static int __init early_init_dt_scan_usablemem(unsigned long node,
 		const char *uname, int depth, void *data)
 {
-	struct memblock_region *usablemem = data;
-	const __be32 *reg;
-	int len;
+	struct memblock_region *usable_rgns = data;
+	const __be32 *reg, *endp;
+	int len, nr = 0;
 
 	if (depth != 1 || strcmp(uname, "chosen") != 0)
 		return 0;
@@ -212,22 +221,36 @@ static int __init early_init_dt_scan_usablemem(unsigned long node,
 	if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
 		return 1;
 
-	usablemem->base = dt_mem_next_cell(dt_root_addr_cells, &reg);
-	usablemem->size = dt_mem_next_cell(dt_root_size_cells, &reg);
+	endp = reg + (len / sizeof(__be32));
+	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+		usable_rgns[nr].base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+		usable_rgns[nr].size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+		if (++nr >= MAX_USABLE_RANGES)
+			break;
+	}
 
 	return 1;
 }
 
 static void __init fdt_enforce_memory_region(void)
 {
-	struct memblock_region reg = {
-		.size = 0,
+	struct memblock_region usable_rgns[MAX_USABLE_RANGES] = {
+		{ .size = 0 },
+		{ .size = 0 }
 	};
 
-	of_scan_flat_dt(early_init_dt_scan_usablemem, &reg);
+	of_scan_flat_dt(early_init_dt_scan_usablemem, &usable_rgns);
 
-	if (reg.size)
-		memblock_cap_memory_range(reg.base, reg.size);
+	/*
+	 * The first range of usable-memory regions is for crash dump
+	 * kernel with only one region or for high region with two regions,
+	 * the second range is dedicated for low region if exist.
+	 */
+	if (usable_rgns[0].size)
+		memblock_cap_memory_range(usable_rgns[0].base, usable_rgns[0].size);
+	if (usable_rgns[1].size)
+		memblock_add(usable_rgns[1].base, usable_rgns[1].size);
 }
 
 void __init arm64_memblock_init(void)
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux, usable-memory-range
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices and never mapped by the first kernel.
This memory range is advertised to crash dump kernel via DT property
under /chosen,
	linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]>

We reused the DT property linux,usable-memory-range and made the low
memory region as the second range "BASE2 SIZE2", which keeps compatibility
with existing user-space and older kdump kernels.

Crash dump kernel reads this property at boot time and call memblock_add()
to add the low memory region after memblock_cap_memory_range() has been
called.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/mm/init.c | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d20f5c444ebf..180a25b67f55 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -68,6 +68,15 @@ static void __init reserve_crashkernel(void)
 }
 #endif
 
+/*
+ * The main usage of linux,usable-memory-range is for crash dump kernel.
+ * Originally, the number of usable-memory regions is one. Now there may
+ * be two regions, low region and high region.
+ * To make compatibility with existing user-space and older kdump, the low
+ * region is always the last range of linux,usable-memory-range if exist.
+ */
+#define MAX_USABLE_RANGES	2
+
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
 		const char *uname, int depth, void *data)
@@ -201,9 +210,9 @@ early_param("mem", early_mem);
 static int __init early_init_dt_scan_usablemem(unsigned long node,
 		const char *uname, int depth, void *data)
 {
-	struct memblock_region *usablemem = data;
-	const __be32 *reg;
-	int len;
+	struct memblock_region *usable_rgns = data;
+	const __be32 *reg, *endp;
+	int len, nr = 0;
 
 	if (depth != 1 || strcmp(uname, "chosen") != 0)
 		return 0;
@@ -212,22 +221,36 @@ static int __init early_init_dt_scan_usablemem(unsigned long node,
 	if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
 		return 1;
 
-	usablemem->base = dt_mem_next_cell(dt_root_addr_cells, &reg);
-	usablemem->size = dt_mem_next_cell(dt_root_size_cells, &reg);
+	endp = reg + (len / sizeof(__be32));
+	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+		usable_rgns[nr].base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+		usable_rgns[nr].size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+		if (++nr >= MAX_USABLE_RANGES)
+			break;
+	}
 
 	return 1;
 }
 
 static void __init fdt_enforce_memory_region(void)
 {
-	struct memblock_region reg = {
-		.size = 0,
+	struct memblock_region usable_rgns[MAX_USABLE_RANGES] = {
+		{ .size = 0 },
+		{ .size = 0 }
 	};
 
-	of_scan_flat_dt(early_init_dt_scan_usablemem, &reg);
+	of_scan_flat_dt(early_init_dt_scan_usablemem, &usable_rgns);
 
-	if (reg.size)
-		memblock_cap_memory_range(reg.base, reg.size);
+	/*
+	 * The first range of usable-memory regions is for crash dump
+	 * kernel with only one region or for high region with two regions,
+	 * the second range is dedicated for low region if exist.
+	 */
+	if (usable_rgns[0].size)
+		memblock_cap_memory_range(usable_rgns[0].base, usable_rgns[0].size);
+	if (usable_rgns[1].size)
+		memblock_add(usable_rgns[1].base, usable_rgns[1].size);
 }
 
 void __init arm64_memblock_init(void)
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux, usable-memory-range
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

When reserving crashkernel in high memory, some low memory is reserved
for crash dump kernel devices and never mapped by the first kernel.
This memory range is advertised to crash dump kernel via DT property
under /chosen,
	linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]>

We reused the DT property linux,usable-memory-range and made the low
memory region as the second range "BASE2 SIZE2", which keeps compatibility
with existing user-space and older kdump kernels.

Crash dump kernel reads this property at boot time and call memblock_add()
to add the low memory region after memblock_cap_memory_range() has been
called.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 arch/arm64/mm/init.c | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d20f5c444ebf..180a25b67f55 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -68,6 +68,15 @@ static void __init reserve_crashkernel(void)
 }
 #endif
 
+/*
+ * The main usage of linux,usable-memory-range is for crash dump kernel.
+ * Originally, the number of usable-memory regions is one. Now there may
+ * be two regions, low region and high region.
+ * To make compatibility with existing user-space and older kdump, the low
+ * region is always the last range of linux,usable-memory-range if exist.
+ */
+#define MAX_USABLE_RANGES	2
+
 #ifdef CONFIG_CRASH_DUMP
 static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
 		const char *uname, int depth, void *data)
@@ -201,9 +210,9 @@ early_param("mem", early_mem);
 static int __init early_init_dt_scan_usablemem(unsigned long node,
 		const char *uname, int depth, void *data)
 {
-	struct memblock_region *usablemem = data;
-	const __be32 *reg;
-	int len;
+	struct memblock_region *usable_rgns = data;
+	const __be32 *reg, *endp;
+	int len, nr = 0;
 
 	if (depth != 1 || strcmp(uname, "chosen") != 0)
 		return 0;
@@ -212,22 +221,36 @@ static int __init early_init_dt_scan_usablemem(unsigned long node,
 	if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells)))
 		return 1;
 
-	usablemem->base = dt_mem_next_cell(dt_root_addr_cells, &reg);
-	usablemem->size = dt_mem_next_cell(dt_root_size_cells, &reg);
+	endp = reg + (len / sizeof(__be32));
+	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+		usable_rgns[nr].base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+		usable_rgns[nr].size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+		if (++nr >= MAX_USABLE_RANGES)
+			break;
+	}
 
 	return 1;
 }
 
 static void __init fdt_enforce_memory_region(void)
 {
-	struct memblock_region reg = {
-		.size = 0,
+	struct memblock_region usable_rgns[MAX_USABLE_RANGES] = {
+		{ .size = 0 },
+		{ .size = 0 }
 	};
 
-	of_scan_flat_dt(early_init_dt_scan_usablemem, &reg);
+	of_scan_flat_dt(early_init_dt_scan_usablemem, &usable_rgns);
 
-	if (reg.size)
-		memblock_cap_memory_range(reg.base, reg.size);
+	/*
+	 * The first range of usable-memory regions is for crash dump
+	 * kernel with only one region or for high region with two regions,
+	 * the second range is dedicated for low region if exist.
+	 */
+	if (usable_rgns[0].size)
+		memblock_cap_memory_range(usable_rgns[0].base, usable_rgns[0].size);
+	if (usable_rgns[1].size)
+		memblock_add(usable_rgns[1].base, usable_rgns[1].size);
 }
 
 void __init arm64_memblock_init(void)
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 11/11] kdump: update Documentation about crashkernel
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-01-30  7:10   ` Chen Zhou
  -1 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, chenzhou10, linux-doc,
	linux-arm-kernel, linux-kernel, kexec, John Donnelly

For arm64, the behavior of crashkernel=X has been changed, which
tries low allocation in DMA zone and fall back to high allocation
if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

So update the Documentation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
 .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index 75a9dd98e76e..0877c76f8015 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -299,7 +299,16 @@ Boot into System Kernel
    "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
    starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
 
-   On x86 and x86_64, use "crashkernel=64M@16M".
+   On x86 use "crashkernel=64M@16M".
+
+   On x86_64, use "crashkernel=X" to select a region under 4G first, and
+   fall back to reserve region above 4G. And go for high allocation
+   directly if the required size is too large.
+   We can also use "crashkernel=X,high" to select a region above 4G, which
+   also tries to allocate at least 256M below 4G automatically and
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from specified
+   start address X.
 
    On ppc64, use "crashkernel=128M@32M".
 
@@ -316,8 +325,15 @@ Boot into System Kernel
    kernel will automatically locate the crash kernel image within the
    first 512MB of RAM if X is not given.
 
-   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
-   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
+   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
+   fall back to high allocation if it fails.
+   We can also use "crashkernel=X,high" to select a high region above
+   DMA zone, which also tries to allocate at least 256M low memory in
+   DMA zone automatically.
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from
+   specified start address X. Note that the start address of the kernel,
+   X if explicitly specified, must be aligned to 2MiB (0x200000).
 
 Load the Dump-capture Kernel
 ============================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a10b545c2070..908e5c8b61ba 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -738,6 +738,9 @@
 			[KNL, X86-64] Select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
+			[KNL, arm64] Try low allocation in DMA zone and fall back
+			to high allocation if it fails when '@offset' hasn't been
+			specified.
 			See Documentation/admin-guide/kdump/kdump.rst for further details.
 
 	crashkernel=range1:size1[,range2:size2,...][@offset]
@@ -754,6 +757,8 @@
 			Otherwise memory region will be allocated below 4G, if
 			available.
 			It will be ignored if crashkernel=X is specified.
+			[KNL, arm64] range in high memory.
+			Allow kernel to allocate physical memory region from top.
 	crashkernel=size[KMG],low
 			[KNL, X86-64] range under 4G. When crashkernel=X,high
 			is passed, kernel could allocate physical memory region
@@ -762,13 +767,15 @@
 			requires at least 64M+32K low memory, also enough extra
 			low memory is needed to make sure DMA buffers for 32-bit
 			devices won't run out. Kernel would try to allocate at
-			at least 256M below 4G automatically.
+			least 256M below 4G automatically.
 			This one let user to specify own low range under 4G
 			for second kernel instead.
 			0: to disable low allocation.
 			It will be ignored when crashkernel=X,high is not used
 			or memory reserved is below 4G.
-
+			[KNL, arm64] range in low memory.
+			This one let user to specify a low range in DMA zone for
+			crash dump kernel.
 	cryptomgr.notests
 			[KNL] Disable crypto self-tests
 
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

For arm64, the behavior of crashkernel=X has been changed, which
tries low allocation in DMA zone and fall back to high allocation
if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

So update the Documentation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
 .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index 75a9dd98e76e..0877c76f8015 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -299,7 +299,16 @@ Boot into System Kernel
    "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
    starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
 
-   On x86 and x86_64, use "crashkernel=64M@16M".
+   On x86 use "crashkernel=64M@16M".
+
+   On x86_64, use "crashkernel=X" to select a region under 4G first, and
+   fall back to reserve region above 4G. And go for high allocation
+   directly if the required size is too large.
+   We can also use "crashkernel=X,high" to select a region above 4G, which
+   also tries to allocate at least 256M below 4G automatically and
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from specified
+   start address X.
 
    On ppc64, use "crashkernel=128M@32M".
 
@@ -316,8 +325,15 @@ Boot into System Kernel
    kernel will automatically locate the crash kernel image within the
    first 512MB of RAM if X is not given.
 
-   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
-   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
+   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
+   fall back to high allocation if it fails.
+   We can also use "crashkernel=X,high" to select a high region above
+   DMA zone, which also tries to allocate at least 256M low memory in
+   DMA zone automatically.
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from
+   specified start address X. Note that the start address of the kernel,
+   X if explicitly specified, must be aligned to 2MiB (0x200000).
 
 Load the Dump-capture Kernel
 ============================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a10b545c2070..908e5c8b61ba 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -738,6 +738,9 @@
 			[KNL, X86-64] Select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
+			[KNL, arm64] Try low allocation in DMA zone and fall back
+			to high allocation if it fails when '@offset' hasn't been
+			specified.
 			See Documentation/admin-guide/kdump/kdump.rst for further details.
 
 	crashkernel=range1:size1[,range2:size2,...][@offset]
@@ -754,6 +757,8 @@
 			Otherwise memory region will be allocated below 4G, if
 			available.
 			It will be ignored if crashkernel=X is specified.
+			[KNL, arm64] range in high memory.
+			Allow kernel to allocate physical memory region from top.
 	crashkernel=size[KMG],low
 			[KNL, X86-64] range under 4G. When crashkernel=X,high
 			is passed, kernel could allocate physical memory region
@@ -762,13 +767,15 @@
 			requires at least 64M+32K low memory, also enough extra
 			low memory is needed to make sure DMA buffers for 32-bit
 			devices won't run out. Kernel would try to allocate at
-			at least 256M below 4G automatically.
+			least 256M below 4G automatically.
 			This one let user to specify own low range under 4G
 			for second kernel instead.
 			0: to disable low allocation.
 			It will be ignored when crashkernel=X,high is not used
 			or memory reserved is below 4G.
-
+			[KNL, arm64] range in low memory.
+			This one let user to specify a low range in DMA zone for
+			crash dump kernel.
 	cryptomgr.notests
 			[KNL] Disable crypto self-tests
 
-- 
2.20.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-01-30  7:10   ` Chen Zhou
  0 siblings, 0 replies; 126+ messages in thread
From: Chen Zhou @ 2021-01-30  7:10 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: John Donnelly, wangkefeng.wang, arnd, xiexiuqi, chenzhou10,
	linux-doc, kexec, linux-kernel, robh+dt, horms, james.morse,
	huawei.libin, guohanjun, linux-arm-kernel

For arm64, the behavior of crashkernel=X has been changed, which
tries low allocation in DMA zone and fall back to high allocation
if it fails.

We can also use "crashkernel=X,high" to select a high region above
DMA zone, which also tries to allocate at least 256M low memory in
DMA zone automatically and "crashkernel=Y,low" can be used to allocate
specified size low memory.

So update the Documentation.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
---
 Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
 .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
index 75a9dd98e76e..0877c76f8015 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -299,7 +299,16 @@ Boot into System Kernel
    "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
    starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
 
-   On x86 and x86_64, use "crashkernel=64M@16M".
+   On x86 use "crashkernel=64M@16M".
+
+   On x86_64, use "crashkernel=X" to select a region under 4G first, and
+   fall back to reserve region above 4G. And go for high allocation
+   directly if the required size is too large.
+   We can also use "crashkernel=X,high" to select a region above 4G, which
+   also tries to allocate at least 256M below 4G automatically and
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from specified
+   start address X.
 
    On ppc64, use "crashkernel=128M@32M".
 
@@ -316,8 +325,15 @@ Boot into System Kernel
    kernel will automatically locate the crash kernel image within the
    first 512MB of RAM if X is not given.
 
-   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
-   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
+   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
+   fall back to high allocation if it fails.
+   We can also use "crashkernel=X,high" to select a high region above
+   DMA zone, which also tries to allocate at least 256M low memory in
+   DMA zone automatically.
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
+   Use "crashkernel=Y@X" if you really have to reserve memory from
+   specified start address X. Note that the start address of the kernel,
+   X if explicitly specified, must be aligned to 2MiB (0x200000).
 
 Load the Dump-capture Kernel
 ============================
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a10b545c2070..908e5c8b61ba 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -738,6 +738,9 @@
 			[KNL, X86-64] Select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
+			[KNL, arm64] Try low allocation in DMA zone and fall back
+			to high allocation if it fails when '@offset' hasn't been
+			specified.
 			See Documentation/admin-guide/kdump/kdump.rst for further details.
 
 	crashkernel=range1:size1[,range2:size2,...][@offset]
@@ -754,6 +757,8 @@
 			Otherwise memory region will be allocated below 4G, if
 			available.
 			It will be ignored if crashkernel=X is specified.
+			[KNL, arm64] range in high memory.
+			Allow kernel to allocate physical memory region from top.
 	crashkernel=size[KMG],low
 			[KNL, X86-64] range under 4G. When crashkernel=X,high
 			is passed, kernel could allocate physical memory region
@@ -762,13 +767,15 @@
 			requires at least 64M+32K low memory, also enough extra
 			low memory is needed to make sure DMA buffers for 32-bit
 			devices won't run out. Kernel would try to allocate at
-			at least 256M below 4G automatically.
+			least 256M below 4G automatically.
 			This one let user to specify own low range under 4G
 			for second kernel instead.
 			0: to disable low allocation.
 			It will be ignored when crashkernel=X,high is not used
 			or memory reserved is below 4G.
-
+			[KNL, arm64] range in low memory.
+			This one let user to specify a low range in DMA zone for
+			crash dump kernel.
 	cryptomgr.notests
 			[KNL] Disable crypto self-tests
 
-- 
2.20.1


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply related	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-01-30 17:53     ` Randy Dunlap
  -1 siblings, 0 replies; 126+ messages in thread
From: Randy Dunlap @ 2021-01-30 17:53 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, linux-doc, linux-arm-kernel,
	linux-kernel, kexec

Hi--

On 1/29/21 11:10 PM, Chen Zhou wrote:
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt

All of the "arm64" instances in [square brackets] should be "ARM64".

> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back

			      here

> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.

			      here

> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.

			      here

> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.


Thanks.

-- 
~Randy


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-01-30 17:53     ` Randy Dunlap
  0 siblings, 0 replies; 126+ messages in thread
From: Randy Dunlap @ 2021-01-30 17:53 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi--

On 1/29/21 11:10 PM, Chen Zhou wrote:
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt

All of the "arm64" instances in [square brackets] should be "ARM64".

> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back

			      here

> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.

			      here

> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.

			      here

> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.


Thanks.

-- 
~Randy


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-01-30 17:53     ` Randy Dunlap
  0 siblings, 0 replies; 126+ messages in thread
From: Randy Dunlap @ 2021-01-30 17:53 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi--

On 1/29/21 11:10 PM, Chen Zhou wrote:
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt

All of the "arm64" instances in [square brackets] should be "ARM64".

> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back

			      here

> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.

			      here

> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.

			      here

> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.


Thanks.

-- 
~Randy


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
  2021-01-30 17:53     ` Randy Dunlap
  (?)
@ 2021-02-04  1:53       ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-04  1:53 UTC (permalink / raw)
  To: Randy Dunlap, mingo, tglx, rppt, dyoung, bhe, catalin.marinas,
	will, nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, linux-doc, linux-arm-kernel,
	linux-kernel, kexec

Hi Randy,


On 2021/1/31 1:53, Randy Dunlap wrote:
> Hi--
>
> On 1/29/21 11:10 PM, Chen Zhou wrote:
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
> All of the "arm64" instances in [square brackets] should be "ARM64".
Got it, thanks for your review.

Thanks,
Chen Zhou
>
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> 			      here
>
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
> 			      here
>
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
> 			      here
>
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>
> Thanks.
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-04  1:53       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-04  1:53 UTC (permalink / raw)
  To: Randy Dunlap, mingo, tglx, rppt, dyoung, bhe, catalin.marinas,
	will, nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi Randy,


On 2021/1/31 1:53, Randy Dunlap wrote:
> Hi--
>
> On 1/29/21 11:10 PM, Chen Zhou wrote:
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
> All of the "arm64" instances in [square brackets] should be "ARM64".
Got it, thanks for your review.

Thanks,
Chen Zhou
>
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> 			      here
>
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
> 			      here
>
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
> 			      here
>
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>
> Thanks.
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-04  1:53       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-04  1:53 UTC (permalink / raw)
  To: Randy Dunlap, mingo, tglx, rppt, dyoung, bhe, catalin.marinas,
	will, nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi Randy,


On 2021/1/31 1:53, Randy Dunlap wrote:
> Hi--
>
> On 1/29/21 11:10 PM, Chen Zhou wrote:
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
> All of the "arm64" instances in [square brackets] should be "ARM64".
Got it, thanks for your review.

Thanks,
Chen Zhou
>
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> 			      here
>
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
> 			      here
>
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
> 			      here
>
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>
> Thanks.
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-04 16:20     ` Nicolas Saenz Julienne
  -1 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:20 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, linux-doc, linux-arm-kernel,
	linux-kernel, kexec

[-- Attachment #1: Type: text/plain, Size: 1986 bytes --]

Hi Chen,

On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> upper bound of high crash memory, use macroes instead.
> 
> Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> of crash kernel reservation.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/arm64/include/asm/kexec.h | 6 ++++++
>  arch/arm64/mm/init.c           | 6 +++---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index d24b527e8c00..3f6ecae0bc68 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -25,6 +25,12 @@
>  
> 
>  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
>  
> 
> +/* 2M alignment for crash kernel regions */
> +#define CRASH_ALIGN	SZ_2M
> +
> +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit

I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
define.

> +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> +
>  #ifndef __ASSEMBLY__
>  
> 
>  /**
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 709d98fea90c..912f64f505f7 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
>  
> 
>  	if (crash_base == 0) {
>  		/* Current arm64 boot protocol requires 2MB alignment */
> -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> -				crash_size, SZ_2M);
> +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> +				crash_size, CRASH_ALIGN);

Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
it).

Regards,
Nicolas


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^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-02-04 16:20     ` Nicolas Saenz Julienne
  0 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:20 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel


[-- Attachment #1.1: Type: text/plain, Size: 1986 bytes --]

Hi Chen,

On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> upper bound of high crash memory, use macroes instead.
> 
> Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> of crash kernel reservation.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/arm64/include/asm/kexec.h | 6 ++++++
>  arch/arm64/mm/init.c           | 6 +++---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index d24b527e8c00..3f6ecae0bc68 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -25,6 +25,12 @@
>  
> 
>  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
>  
> 
> +/* 2M alignment for crash kernel regions */
> +#define CRASH_ALIGN	SZ_2M
> +
> +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit

I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
define.

> +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> +
>  #ifndef __ASSEMBLY__
>  
> 
>  /**
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 709d98fea90c..912f64f505f7 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
>  
> 
>  	if (crash_base == 0) {
>  		/* Current arm64 boot protocol requires 2MB alignment */
> -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> -				crash_size, SZ_2M);
> +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> +				crash_size, CRASH_ALIGN);

Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
it).

Regards,
Nicolas


[-- Attachment #1.2: This is a digitally signed message part --]
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[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-02-04 16:20     ` Nicolas Saenz Julienne
  0 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:20 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel


[-- Attachment #1.1: Type: text/plain, Size: 1986 bytes --]

Hi Chen,

On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> upper bound of high crash memory, use macroes instead.
> 
> Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> of crash kernel reservation.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/arm64/include/asm/kexec.h | 6 ++++++
>  arch/arm64/mm/init.c           | 6 +++---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index d24b527e8c00..3f6ecae0bc68 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -25,6 +25,12 @@
>  
> 
>  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
>  
> 
> +/* 2M alignment for crash kernel regions */
> +#define CRASH_ALIGN	SZ_2M
> +
> +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit

I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
define.

> +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> +
>  #ifndef __ASSEMBLY__
>  
> 
>  /**
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 709d98fea90c..912f64f505f7 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
>  
> 
>  	if (crash_base == 0) {
>  		/* Current arm64 boot protocol requires 2MB alignment */
> -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> -				crash_size, SZ_2M);
> +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> +				crash_size, CRASH_ALIGN);

Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
it).

Regards,
Nicolas


[-- Attachment #1.2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[-- Attachment #2: Type: text/plain, Size: 143 bytes --]

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
  2021-02-04 16:20     ` Nicolas Saenz Julienne
  (?)
@ 2021-02-04 16:27       ` Nicolas Saenz Julienne
  -1 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:27 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, linux-doc, linux-arm-kernel,
	linux-kernel, kexec

[-- Attachment #1: Type: text/plain, Size: 2335 bytes --]

On Thu, 2021-02-04 at 17:20 +0100, Nicolas Saenz Julienne wrote:
> Hi Chen,
> 
> On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> > Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> > for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> > upper bound of high crash memory, use macroes instead.
> > 
> > Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> > of crash kernel reservation.
> > 
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> > ---
> >  arch/arm64/include/asm/kexec.h | 6 ++++++
> >  arch/arm64/mm/init.c           | 6 +++---
> >  2 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> > index d24b527e8c00..3f6ecae0bc68 100644
> > --- a/arch/arm64/include/asm/kexec.h
> > +++ b/arch/arm64/include/asm/kexec.h
> > @@ -25,6 +25,12 @@
> >  
> > 
> >  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
> >  
> > 
> > +/* 2M alignment for crash kernel regions */
> > +#define CRASH_ALIGN	SZ_2M
> > +
> > +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
> 
> I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
> define.
> 
> > +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> > +
> >  #ifndef __ASSEMBLY__
> >  
> > 
> >  /**
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 709d98fea90c..912f64f505f7 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
> >  
> > 
> >  	if (crash_base == 0) {
> >  		/* Current arm64 boot protocol requires 2MB alignment */
> > -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> > -				crash_size, SZ_2M);
> > +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> > +				crash_size, CRASH_ALIGN);
> 
> Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
> memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
> it).

Forget about these coments, I now see that you're deleting this whole function
on the next patch and defaulting to a generic implementation. Sorry for the
noise.

Regards,
Nicolas


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^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-02-04 16:27       ` Nicolas Saenz Julienne
  0 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:27 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel


[-- Attachment #1.1: Type: text/plain, Size: 2335 bytes --]

On Thu, 2021-02-04 at 17:20 +0100, Nicolas Saenz Julienne wrote:
> Hi Chen,
> 
> On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> > Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> > for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> > upper bound of high crash memory, use macroes instead.
> > 
> > Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> > of crash kernel reservation.
> > 
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> > ---
> >  arch/arm64/include/asm/kexec.h | 6 ++++++
> >  arch/arm64/mm/init.c           | 6 +++---
> >  2 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> > index d24b527e8c00..3f6ecae0bc68 100644
> > --- a/arch/arm64/include/asm/kexec.h
> > +++ b/arch/arm64/include/asm/kexec.h
> > @@ -25,6 +25,12 @@
> >  
> > 
> >  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
> >  
> > 
> > +/* 2M alignment for crash kernel regions */
> > +#define CRASH_ALIGN	SZ_2M
> > +
> > +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
> 
> I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
> define.
> 
> > +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> > +
> >  #ifndef __ASSEMBLY__
> >  
> > 
> >  /**
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 709d98fea90c..912f64f505f7 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
> >  
> > 
> >  	if (crash_base == 0) {
> >  		/* Current arm64 boot protocol requires 2MB alignment */
> > -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> > -				crash_size, SZ_2M);
> > +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> > +				crash_size, CRASH_ALIGN);
> 
> Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
> memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
> it).

Forget about these coments, I now see that you're deleting this whole function
on the next patch and defaulting to a generic implementation. Sorry for the
noise.

Regards,
Nicolas


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_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation
@ 2021-02-04 16:27       ` Nicolas Saenz Julienne
  0 siblings, 0 replies; 126+ messages in thread
From: Nicolas Saenz Julienne @ 2021-02-04 16:27 UTC (permalink / raw)
  To: Chen Zhou, mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	corbet, John.P.donnelly, bhsharma, prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel


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On Thu, 2021-02-04 at 17:20 +0100, Nicolas Saenz Julienne wrote:
> Hi Chen,
> 
> On Sat, 2021-01-30 at 15:10 +0800, Chen Zhou wrote:
> > Introduce macro CRASH_ALIGN for alignment, macro CRASH_ADDR_LOW_MAX
> > for upper bound of low crash memory, macro CRASH_ADDR_HIGH_MAX for
> > upper bound of high crash memory, use macroes instead.
> > 
> > Besides, keep consistent with x86, use CRASH_ALIGN as the lower bound
> > of crash kernel reservation.
> > 
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> > ---
> >  arch/arm64/include/asm/kexec.h | 6 ++++++
> >  arch/arm64/mm/init.c           | 6 +++---
> >  2 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> > index d24b527e8c00..3f6ecae0bc68 100644
> > --- a/arch/arm64/include/asm/kexec.h
> > +++ b/arch/arm64/include/asm/kexec.h
> > @@ -25,6 +25,12 @@
> >  
> > 
> >  #define KEXEC_ARCH KEXEC_ARCH_AARCH64
> >  
> > 
> > +/* 2M alignment for crash kernel regions */
> > +#define CRASH_ALIGN	SZ_2M
> > +
> > +#define CRASH_ADDR_LOW_MAX	arm64_dma_phys_limit
> 
> I wonder if you could use 'ARCH_LOW_ADDRESS_LIMIT', instead of creating a new
> define.
> 
> > +#define CRASH_ADDR_HIGH_MAX	MEMBLOCK_ALLOC_ACCESSIBLE
> > +
> >  #ifndef __ASSEMBLY__
> >  
> > 
> >  /**
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 709d98fea90c..912f64f505f7 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -84,8 +84,8 @@ static void __init reserve_crashkernel(void)
> >  
> > 
> >  	if (crash_base == 0) {
> >  		/* Current arm64 boot protocol requires 2MB alignment */
> > -		crash_base = memblock_find_in_range(0, arm64_dma_phys_limit,
> > -				crash_size, SZ_2M);
> > +		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX,
> > +				crash_size, CRASH_ALIGN);
> 
> Actually we could get rid of CRASH_ADDR_LOW_MAX altogether if we used
> memblock_alloc_low() here (modulo the slight refactoring needed to accommodate
> it).

Forget about these coments, I now see that you're deleting this whole function
on the next patch and defaulting to a generic implementation. Sorry for the
noise.

Regards,
Nicolas


[-- Attachment #1.2: This is a digitally signed message part --]
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_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
  2021-01-30  7:10 ` Chen Zhou
  (?)
@ 2021-02-08  6:46   ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-08  6:46 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: horms, robh+dt, arnd, james.morse, xiexiuqi, guohanjun,
	huawei.libin, wangkefeng.wang, linux-doc, linux-arm-kernel,
	linux-kernel, kexec

Hi all,

Friendly ping...


On 2021/1/30 15:10, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
>
> To solve these issues, change the behavior of crashkernel=X.
> crashkernel=X tries low allocation in DMA zone and fall back to high
> allocation if it fails.
>
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
>
> When reserving crashkernel in high memory, some low memory is reserved
> for crash dump kernel devices. So there may be two regions reserved for
> crash dump kernel.
> In order to distinct from the high region and make no effect to the use
> of existing kexec-tools, rename the low region as "Crash kernel (low)",
> and pass the low region by reusing DT property
> "linux,usable-memory-range". We made the low memory region as the last
> range of "linux,usable-memory-range" to keep compatibility with existing
> user-space and older kdump kernels.
>
> Besides, we need to modify kexec-tools:
> arm64: support more than one crash kernel regions(see [1])
>
> Another update is document about DT property 'linux,usable-memory-range':
> schemas: update 'linux,usable-memory-range' node schema(see [2])
>
> This patchset contains the following eleven patches:
> 0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
> 0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
> 0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
> 0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
> 0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
> 0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
> 0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
> 0008-arm64-kdump-reimplement-crashkernel-X.patch
> 0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
> 0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
> 0011-kdump-update-Documentation-about-crashkernel.patch
>
> 0001-0004 are some x86 cleanups which prepares for making
> functionsreserve_crashkernel[_low]() generic.
> 0005 makes functions reserve_crashkernel[_low]() generic.
> 0006 fix compiling warning.
> 0007-0009 reimplements arm64 crashkernel=X.
> 0010 adds memory for devices by DT property linux,usable-memory-range.
> 0011 updates the doc.
>
> Changes since [v13]
> - Rebased on top of 5.11-rc5.
> - Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
> Since reserve_crashkernel[_low]() implementations are quite similar on
> other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
> arch/Kconfig and select this by X86 and ARM64.
> - Some minor cleanup.
>
> Changes since [v12]
> - Rebased on top of 5.10-rc1.
> - Keep CRASH_ALIGN as 16M suggested by Dave.
> - Drop patch "kdump: add threshold for the required memory".
> - Add Tested-by from John.
>
> Changes since [v11]
> - Rebased on top of 5.9-rc4.
> - Make the function reserve_crashkernel() of x86 generic.
> Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
> and arm64 use the generic version to reimplement crashkernel=X.
>
> Changes since [v10]
> - Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.
>
> Changes since [v9]
> - Patch 1 add Acked-by from Dave.
> - Update patch 5 according to Dave's comments.
> - Update chosen schema.
>
> Changes since [v8]
> - Reuse DT property "linux,usable-memory-range".
> Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
> memory region.
> - Fix kdump broken with ZONE_DMA reintroduced.
> - Update chosen schema.
>
> Changes since [v7]
> - Move x86 CRASH_ALIGN to 2M
> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> - Update Documentation/devicetree/bindings/chosen.txt.
> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
> suggested by Arnd.
> - Add Tested-by from Jhon and pk.
>
> Changes since [v6]
> - Fix build errors reported by kbuild test robot.
>
> Changes since [v5]
> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> - Delete crashkernel=X,high.
> - Modify crashkernel=X,low.
> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> pass to crash dump kernel by DT property "linux,low-memory-range".
> - Update Documentation/admin-guide/kdump/kdump.rst.
>
> Changes since [v4]
> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>
> Changes since [v3]
> - Add memblock_cap_memory_ranges back for multiple ranges.
> - Fix some compiling warnings.
>
> Changes since [v2]
> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> patch.
>
> Changes since [v1]:
> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> in fdt_enforce_memory_region().
> There are at most two crash kernel regions, for two crash kernel regions
> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> and then remove the memory range in the middle.
>
> [1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
> [2]: https://github.com/robherring/dt-schema/pull/19 
> [v1]: https://lkml.org/lkml/2019/4/2/1174
> [v2]: https://lkml.org/lkml/2019/4/9/86
> [v3]: https://lkml.org/lkml/2019/4/9/306
> [v4]: https://lkml.org/lkml/2019/4/15/273
> [v5]: https://lkml.org/lkml/2019/5/6/1360
> [v6]: https://lkml.org/lkml/2019/8/30/142
> [v7]: https://lkml.org/lkml/2019/12/23/411
> [v8]: https://lkml.org/lkml/2020/5/21/213
> [v9]: https://lkml.org/lkml/2020/6/28/73
> [v10]: https://lkml.org/lkml/2020/7/2/1443
> [v11]: https://lkml.org/lkml/2020/8/1/150
> [v12]: https://lkml.org/lkml/2020/9/7/1037
> [v13]: https://lkml.org/lkml/2020/10/31/34
>
> Chen Zhou (11):
>   x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
>   x86: kdump: make the lower bound of crash kernel reservation
>     consistent
>   x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
>     reserve_crashkernel()
>   x86: kdump: move xen_pv_domain() check and insert_resource() to
>     setup_arch()
>   x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
>   x86/elf: Move vmcore_elf_check_arch_cross to
>     arch/x86/include/asm/elf.h
>   arm64: kdump: introduce some macroes for crash kernel reservation
>   arm64: kdump: reimplement crashkernel=X
>   x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
>   arm64: kdump: add memory for devices by DT property
>     linux,usable-memory-range
>   kdump: update Documentation about crashkernel
>
>  Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
>  .../admin-guide/kernel-parameters.txt         |  11 +-
>  arch/Kconfig                                  |   3 +
>  arch/arm64/Kconfig                            |   1 +
>  arch/arm64/include/asm/kexec.h                |  10 ++
>  arch/arm64/kernel/setup.c                     |  13 +-
>  arch/arm64/mm/init.c                          | 111 +++++-------
>  arch/x86/Kconfig                              |   2 +
>  arch/x86/include/asm/elf.h                    |   3 +
>  arch/x86/include/asm/kexec.h                  |  31 +++-
>  arch/x86/kernel/setup.c                       | 163 ++----------------
>  include/linux/crash_core.h                    |   3 +
>  include/linux/kexec.h                         |   2 -
>  kernel/crash_core.c                           | 156 +++++++++++++++++
>  kernel/kexec_core.c                           |  17 --
>  15 files changed, 303 insertions(+), 245 deletions(-)
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
@ 2021-02-08  6:46   ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-08  6:46 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi all,

Friendly ping...


On 2021/1/30 15:10, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
>
> To solve these issues, change the behavior of crashkernel=X.
> crashkernel=X tries low allocation in DMA zone and fall back to high
> allocation if it fails.
>
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
>
> When reserving crashkernel in high memory, some low memory is reserved
> for crash dump kernel devices. So there may be two regions reserved for
> crash dump kernel.
> In order to distinct from the high region and make no effect to the use
> of existing kexec-tools, rename the low region as "Crash kernel (low)",
> and pass the low region by reusing DT property
> "linux,usable-memory-range". We made the low memory region as the last
> range of "linux,usable-memory-range" to keep compatibility with existing
> user-space and older kdump kernels.
>
> Besides, we need to modify kexec-tools:
> arm64: support more than one crash kernel regions(see [1])
>
> Another update is document about DT property 'linux,usable-memory-range':
> schemas: update 'linux,usable-memory-range' node schema(see [2])
>
> This patchset contains the following eleven patches:
> 0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
> 0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
> 0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
> 0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
> 0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
> 0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
> 0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
> 0008-arm64-kdump-reimplement-crashkernel-X.patch
> 0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
> 0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
> 0011-kdump-update-Documentation-about-crashkernel.patch
>
> 0001-0004 are some x86 cleanups which prepares for making
> functionsreserve_crashkernel[_low]() generic.
> 0005 makes functions reserve_crashkernel[_low]() generic.
> 0006 fix compiling warning.
> 0007-0009 reimplements arm64 crashkernel=X.
> 0010 adds memory for devices by DT property linux,usable-memory-range.
> 0011 updates the doc.
>
> Changes since [v13]
> - Rebased on top of 5.11-rc5.
> - Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
> Since reserve_crashkernel[_low]() implementations are quite similar on
> other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
> arch/Kconfig and select this by X86 and ARM64.
> - Some minor cleanup.
>
> Changes since [v12]
> - Rebased on top of 5.10-rc1.
> - Keep CRASH_ALIGN as 16M suggested by Dave.
> - Drop patch "kdump: add threshold for the required memory".
> - Add Tested-by from John.
>
> Changes since [v11]
> - Rebased on top of 5.9-rc4.
> - Make the function reserve_crashkernel() of x86 generic.
> Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
> and arm64 use the generic version to reimplement crashkernel=X.
>
> Changes since [v10]
> - Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.
>
> Changes since [v9]
> - Patch 1 add Acked-by from Dave.
> - Update patch 5 according to Dave's comments.
> - Update chosen schema.
>
> Changes since [v8]
> - Reuse DT property "linux,usable-memory-range".
> Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
> memory region.
> - Fix kdump broken with ZONE_DMA reintroduced.
> - Update chosen schema.
>
> Changes since [v7]
> - Move x86 CRASH_ALIGN to 2M
> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> - Update Documentation/devicetree/bindings/chosen.txt.
> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
> suggested by Arnd.
> - Add Tested-by from Jhon and pk.
>
> Changes since [v6]
> - Fix build errors reported by kbuild test robot.
>
> Changes since [v5]
> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> - Delete crashkernel=X,high.
> - Modify crashkernel=X,low.
> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> pass to crash dump kernel by DT property "linux,low-memory-range".
> - Update Documentation/admin-guide/kdump/kdump.rst.
>
> Changes since [v4]
> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>
> Changes since [v3]
> - Add memblock_cap_memory_ranges back for multiple ranges.
> - Fix some compiling warnings.
>
> Changes since [v2]
> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> patch.
>
> Changes since [v1]:
> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> in fdt_enforce_memory_region().
> There are at most two crash kernel regions, for two crash kernel regions
> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> and then remove the memory range in the middle.
>
> [1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
> [2]: https://github.com/robherring/dt-schema/pull/19 
> [v1]: https://lkml.org/lkml/2019/4/2/1174
> [v2]: https://lkml.org/lkml/2019/4/9/86
> [v3]: https://lkml.org/lkml/2019/4/9/306
> [v4]: https://lkml.org/lkml/2019/4/15/273
> [v5]: https://lkml.org/lkml/2019/5/6/1360
> [v6]: https://lkml.org/lkml/2019/8/30/142
> [v7]: https://lkml.org/lkml/2019/12/23/411
> [v8]: https://lkml.org/lkml/2020/5/21/213
> [v9]: https://lkml.org/lkml/2020/6/28/73
> [v10]: https://lkml.org/lkml/2020/7/2/1443
> [v11]: https://lkml.org/lkml/2020/8/1/150
> [v12]: https://lkml.org/lkml/2020/9/7/1037
> [v13]: https://lkml.org/lkml/2020/10/31/34
>
> Chen Zhou (11):
>   x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
>   x86: kdump: make the lower bound of crash kernel reservation
>     consistent
>   x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
>     reserve_crashkernel()
>   x86: kdump: move xen_pv_domain() check and insert_resource() to
>     setup_arch()
>   x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
>   x86/elf: Move vmcore_elf_check_arch_cross to
>     arch/x86/include/asm/elf.h
>   arm64: kdump: introduce some macroes for crash kernel reservation
>   arm64: kdump: reimplement crashkernel=X
>   x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
>   arm64: kdump: add memory for devices by DT property
>     linux,usable-memory-range
>   kdump: update Documentation about crashkernel
>
>  Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
>  .../admin-guide/kernel-parameters.txt         |  11 +-
>  arch/Kconfig                                  |   3 +
>  arch/arm64/Kconfig                            |   1 +
>  arch/arm64/include/asm/kexec.h                |  10 ++
>  arch/arm64/kernel/setup.c                     |  13 +-
>  arch/arm64/mm/init.c                          | 111 +++++-------
>  arch/x86/Kconfig                              |   2 +
>  arch/x86/include/asm/elf.h                    |   3 +
>  arch/x86/include/asm/kexec.h                  |  31 +++-
>  arch/x86/kernel/setup.c                       | 163 ++----------------
>  include/linux/crash_core.h                    |   3 +
>  include/linux/kexec.h                         |   2 -
>  kernel/crash_core.c                           | 156 +++++++++++++++++
>  kernel/kexec_core.c                           |  17 --
>  15 files changed, 303 insertions(+), 245 deletions(-)
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump
@ 2021-02-08  6:46   ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-08  6:46 UTC (permalink / raw)
  To: mingo, tglx, rppt, dyoung, bhe, catalin.marinas, will,
	nsaenzjulienne, corbet, John.P.donnelly, bhsharma,
	prabhakar.pkin
  Cc: wangkefeng.wang, arnd, xiexiuqi, linux-doc, kexec, linux-kernel,
	robh+dt, horms, james.morse, huawei.libin, guohanjun,
	linux-arm-kernel

Hi all,

Friendly ping...


On 2021/1/30 15:10, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
>
> To solve these issues, change the behavior of crashkernel=X.
> crashkernel=X tries low allocation in DMA zone and fall back to high
> allocation if it fails.
>
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
>
> When reserving crashkernel in high memory, some low memory is reserved
> for crash dump kernel devices. So there may be two regions reserved for
> crash dump kernel.
> In order to distinct from the high region and make no effect to the use
> of existing kexec-tools, rename the low region as "Crash kernel (low)",
> and pass the low region by reusing DT property
> "linux,usable-memory-range". We made the low memory region as the last
> range of "linux,usable-memory-range" to keep compatibility with existing
> user-space and older kdump kernels.
>
> Besides, we need to modify kexec-tools:
> arm64: support more than one crash kernel regions(see [1])
>
> Another update is document about DT property 'linux,usable-memory-range':
> schemas: update 'linux,usable-memory-range' node schema(see [2])
>
> This patchset contains the following eleven patches:
> 0001-x86-kdump-replace-the-hard-coded-alignment-with-macr.patch
> 0002-x86-kdump-make-the-lower-bound-of-crash-kernel-reser.patch
> 0003-x86-kdump-use-macro-CRASH_ADDR_LOW_MAX-in-functions-.patch
> 0004-x86-kdump-move-xen_pv_domain-check-and-insert_resour.patch
> 0005-x86-kdump-move-reserve_crashkernel-_low-into-crash_c.patch
> 0006-x86-elf-Move-vmcore_elf_check_arch_cross-to-arch-x86.patch
> 0007-arm64-kdump-introduce-some-macroes-for-crash-kernel-.patch
> 0008-arm64-kdump-reimplement-crashkernel-X.patch
> 0009-x86-arm64-Add-ARCH_WANT_RESERVE_CRASH_KERNEL-config.patch
> 0010-arm64-kdump-add-memory-for-devices-by-DT-property-li.patch
> 0011-kdump-update-Documentation-about-crashkernel.patch
>
> 0001-0004 are some x86 cleanups which prepares for making
> functionsreserve_crashkernel[_low]() generic.
> 0005 makes functions reserve_crashkernel[_low]() generic.
> 0006 fix compiling warning.
> 0007-0009 reimplements arm64 crashkernel=X.
> 0010 adds memory for devices by DT property linux,usable-memory-range.
> 0011 updates the doc.
>
> Changes since [v13]
> - Rebased on top of 5.11-rc5.
> - Introduce config CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL.
> Since reserve_crashkernel[_low]() implementations are quite similar on
> other architectures, so have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in
> arch/Kconfig and select this by X86 and ARM64.
> - Some minor cleanup.
>
> Changes since [v12]
> - Rebased on top of 5.10-rc1.
> - Keep CRASH_ALIGN as 16M suggested by Dave.
> - Drop patch "kdump: add threshold for the required memory".
> - Add Tested-by from John.
>
> Changes since [v11]
> - Rebased on top of 5.9-rc4.
> - Make the function reserve_crashkernel() of x86 generic.
> Suggested by Catalin, make the function reserve_crashkernel() of x86 generic
> and arm64 use the generic version to reimplement crashkernel=X.
>
> Changes since [v10]
> - Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin.
>
> Changes since [v9]
> - Patch 1 add Acked-by from Dave.
> - Update patch 5 according to Dave's comments.
> - Update chosen schema.
>
> Changes since [v8]
> - Reuse DT property "linux,usable-memory-range".
> Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low
> memory region.
> - Fix kdump broken with ZONE_DMA reintroduced.
> - Update chosen schema.
>
> Changes since [v7]
> - Move x86 CRASH_ALIGN to 2M
> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> - Update Documentation/devicetree/bindings/chosen.txt.
> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt
> suggested by Arnd.
> - Add Tested-by from Jhon and pk.
>
> Changes since [v6]
> - Fix build errors reported by kbuild test robot.
>
> Changes since [v5]
> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> - Delete crashkernel=X,high.
> - Modify crashkernel=X,low.
> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> pass to crash dump kernel by DT property "linux,low-memory-range".
> - Update Documentation/admin-guide/kdump/kdump.rst.
>
> Changes since [v4]
> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>
> Changes since [v3]
> - Add memblock_cap_memory_ranges back for multiple ranges.
> - Fix some compiling warnings.
>
> Changes since [v2]
> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> patch.
>
> Changes since [v1]:
> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> in fdt_enforce_memory_region().
> There are at most two crash kernel regions, for two crash kernel regions
> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> and then remove the memory range in the middle.
>
> [1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html
> [2]: https://github.com/robherring/dt-schema/pull/19 
> [v1]: https://lkml.org/lkml/2019/4/2/1174
> [v2]: https://lkml.org/lkml/2019/4/9/86
> [v3]: https://lkml.org/lkml/2019/4/9/306
> [v4]: https://lkml.org/lkml/2019/4/15/273
> [v5]: https://lkml.org/lkml/2019/5/6/1360
> [v6]: https://lkml.org/lkml/2019/8/30/142
> [v7]: https://lkml.org/lkml/2019/12/23/411
> [v8]: https://lkml.org/lkml/2020/5/21/213
> [v9]: https://lkml.org/lkml/2020/6/28/73
> [v10]: https://lkml.org/lkml/2020/7/2/1443
> [v11]: https://lkml.org/lkml/2020/8/1/150
> [v12]: https://lkml.org/lkml/2020/9/7/1037
> [v13]: https://lkml.org/lkml/2020/10/31/34
>
> Chen Zhou (11):
>   x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
>   x86: kdump: make the lower bound of crash kernel reservation
>     consistent
>   x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions
>     reserve_crashkernel()
>   x86: kdump: move xen_pv_domain() check and insert_resource() to
>     setup_arch()
>   x86: kdump: move reserve_crashkernel[_low]() into crash_core.c
>   x86/elf: Move vmcore_elf_check_arch_cross to
>     arch/x86/include/asm/elf.h
>   arm64: kdump: introduce some macroes for crash kernel reservation
>   arm64: kdump: reimplement crashkernel=X
>   x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
>   arm64: kdump: add memory for devices by DT property
>     linux,usable-memory-range
>   kdump: update Documentation about crashkernel
>
>  Documentation/admin-guide/kdump/kdump.rst     |  22 ++-
>  .../admin-guide/kernel-parameters.txt         |  11 +-
>  arch/Kconfig                                  |   3 +
>  arch/arm64/Kconfig                            |   1 +
>  arch/arm64/include/asm/kexec.h                |  10 ++
>  arch/arm64/kernel/setup.c                     |  13 +-
>  arch/arm64/mm/init.c                          | 111 +++++-------
>  arch/x86/Kconfig                              |   2 +
>  arch/x86/include/asm/elf.h                    |   3 +
>  arch/x86/include/asm/kexec.h                  |  31 +++-
>  arch/x86/kernel/setup.c                       | 163 ++----------------
>  include/linux/crash_core.h                    |   3 +
>  include/linux/kexec.h                         |   2 -
>  kernel/crash_core.c                           | 156 +++++++++++++++++
>  kernel/kexec_core.c                           |  17 --
>  15 files changed, 303 insertions(+), 245 deletions(-)
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-01-30  7:10   ` Chen Zhou
@ 2021-02-18  3:29     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  3:29 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> function reserve_crashkernel() also used 1M alignment. So just
> replace hard-coded alignment 1M with macro CRASH_ALIGN.
> 
> Suggested-by: Dave Young <dyoung@redhat.com>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/include/asm/kexec.h | 3 +++
>  arch/x86/kernel/setup.c      | 5 +----
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 6802c59e8252..be18dc7ae51f 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -18,6 +18,9 @@
>  
>  # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
>  
> +/* 16M alignment for crash kernel regions */
> +#define CRASH_ALIGN		SZ_16M
> +
>  #ifndef __ASSEMBLY__
>  
>  #include <linux/string.h>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 3412c4595efd..da769845597d 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -390,9 +390,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
>  
>  #ifdef CONFIG_KEXEC_CORE
>  
> -/* 16M alignment for crash kernel regions */
> -#define CRASH_ALIGN		SZ_16M
> -
>  /*
>   * Keep the crash kernel below this limit.
>   *
> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>  	} else {
>  		unsigned long long start;
>  
> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>  						  crash_base + crash_size);

Looks good to me, thx.

Acked-by: Baoquan He <bhe@redhat.com>

>  		if (start != crash_base) {
>  			pr_info("crashkernel reservation failed - memory is in use.\n");
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-18  3:29     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  3:29 UTC (permalink / raw)
  To: Chen Zhou
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, xiexiuqi,
	arnd, horms, corbet, catalin.marinas, dyoung, guohanjun,
	linux-kernel, robh+dt, linux-doc, mingo, james.morse,
	nsaenzjulienne, huawei.libin, prabhakar.pkin, tglx, will, rppt

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> function reserve_crashkernel() also used 1M alignment. So just
> replace hard-coded alignment 1M with macro CRASH_ALIGN.
> 
> Suggested-by: Dave Young <dyoung@redhat.com>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/include/asm/kexec.h | 3 +++
>  arch/x86/kernel/setup.c      | 5 +----
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 6802c59e8252..be18dc7ae51f 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -18,6 +18,9 @@
>  
>  # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
>  
> +/* 16M alignment for crash kernel regions */
> +#define CRASH_ALIGN		SZ_16M
> +
>  #ifndef __ASSEMBLY__
>  
>  #include <linux/string.h>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 3412c4595efd..da769845597d 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -390,9 +390,6 @@ static void __init memblock_x86_reserve_range_setup_data(void)
>  
>  #ifdef CONFIG_KEXEC_CORE
>  
> -/* 16M alignment for crash kernel regions */
> -#define CRASH_ALIGN		SZ_16M
> -
>  /*
>   * Keep the crash kernel below this limit.
>   *
> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>  	} else {
>  		unsigned long long start;
>  
> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>  						  crash_base + crash_size);

Looks good to me, thx.

Acked-by: Baoquan He <bhe@redhat.com>

>  		if (start != crash_base) {
>  			pr_info("crashkernel reservation failed - memory is in use.\n");
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-01-30  7:10   ` Chen Zhou
@ 2021-02-18  3:33     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  3:33 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> The lower bounds of crash kernel reservation and crash kernel low
> reservation are different, use the consistent value CRASH_ALIGN.
> 
> Suggested-by: Dave Young <dyoung@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index da769845597d..27470479e4a3 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);

Acked-by: Baoquan He <bhe@redhat.com>

>  	if (!low_base) {
>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>  		       (unsigned long)(low_size >> 20));
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-18  3:33     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  3:33 UTC (permalink / raw)
  To: Chen Zhou
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, xiexiuqi,
	arnd, horms, corbet, catalin.marinas, dyoung, guohanjun,
	linux-kernel, robh+dt, linux-doc, mingo, james.morse,
	nsaenzjulienne, huawei.libin, prabhakar.pkin, tglx, will, rppt

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> The lower bounds of crash kernel reservation and crash kernel low
> reservation are different, use the consistent value CRASH_ALIGN.
> 
> Suggested-by: Dave Young <dyoung@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index da769845597d..27470479e4a3 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);

Acked-by: Baoquan He <bhe@redhat.com>

>  	if (!low_base) {
>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>  		       (unsigned long)(low_size >> 20));
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch()
  2021-01-30  7:10   ` Chen Zhou
@ 2021-02-18  4:14     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  4:14 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We will make the functions reserve_crashkernel() as generic, the
> xen_pv_domain() check in reserve_crashkernel() is relevant only to
> x86, the same as insert_resource() in reserve_crashkernel[_low]().
> So move xen_pv_domain() check and insert_resource() to setup_arch()
> to keep them in x86.
> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 086a04235be4..5d676efc32f6 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -454,7 +454,6 @@ static int __init reserve_crashkernel_low(void)
>  
>  	crashk_low_res.start = low_base;
>  	crashk_low_res.end   = low_base + low_size - 1;
> -	insert_resource(&iomem_resource, &crashk_low_res);
>  #endif
>  	return 0;
>  }
> @@ -478,11 +477,6 @@ static void __init reserve_crashkernel(void)
>  		high = true;
>  	}
>  
> -	if (xen_pv_domain()) {
> -		pr_info("Ignoring crashkernel for a Xen PV domain\n");
> -		return;
> -	}
> -
>  	/* 0 means: find the address automatically */
>  	if (!crash_base) {
>  		/*
> @@ -529,7 +523,6 @@ static void __init reserve_crashkernel(void)
>  
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
> -	insert_resource(&iomem_resource, &crashk_res);
>  }
>  #else
>  static void __init reserve_crashkernel(void)
> @@ -1151,7 +1144,17 @@ void __init setup_arch(char **cmdline_p)
>  	 * Reserve memory for crash kernel after SRAT is parsed so that it
>  	 * won't consume hotpluggable memory.
>  	 */
> -	reserve_crashkernel();
> +	if (xen_pv_domain())
> +		pr_info("Ignoring crashkernel for a Xen PV domain\n");
> +	else {
> +		reserve_crashkernel();
> +#ifdef CONFIG_KEXEC_CORE
> +		if (crashk_res.end > crashk_res.start)
> +			insert_resource(&iomem_resource, &crashk_res);
> +		if (crashk_low_res.end > crashk_low_res.start)
> +			insert_resource(&iomem_resource, &crashk_low_res);
> +#endif

Acked-by: Baoquan He <bhe@redhat.com>

> +	}
>  
>  	memblock_find_dma_reserve();
>  
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch()
@ 2021-02-18  4:14     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  4:14 UTC (permalink / raw)
  To: Chen Zhou
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, xiexiuqi,
	arnd, horms, corbet, catalin.marinas, dyoung, guohanjun,
	linux-kernel, robh+dt, linux-doc, mingo, james.morse,
	nsaenzjulienne, huawei.libin, prabhakar.pkin, tglx, will, rppt

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We will make the functions reserve_crashkernel() as generic, the
> xen_pv_domain() check in reserve_crashkernel() is relevant only to
> x86, the same as insert_resource() in reserve_crashkernel[_low]().
> So move xen_pv_domain() check and insert_resource() to setup_arch()
> to keep them in x86.
> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 086a04235be4..5d676efc32f6 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -454,7 +454,6 @@ static int __init reserve_crashkernel_low(void)
>  
>  	crashk_low_res.start = low_base;
>  	crashk_low_res.end   = low_base + low_size - 1;
> -	insert_resource(&iomem_resource, &crashk_low_res);
>  #endif
>  	return 0;
>  }
> @@ -478,11 +477,6 @@ static void __init reserve_crashkernel(void)
>  		high = true;
>  	}
>  
> -	if (xen_pv_domain()) {
> -		pr_info("Ignoring crashkernel for a Xen PV domain\n");
> -		return;
> -	}
> -
>  	/* 0 means: find the address automatically */
>  	if (!crash_base) {
>  		/*
> @@ -529,7 +523,6 @@ static void __init reserve_crashkernel(void)
>  
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
> -	insert_resource(&iomem_resource, &crashk_res);
>  }
>  #else
>  static void __init reserve_crashkernel(void)
> @@ -1151,7 +1144,17 @@ void __init setup_arch(char **cmdline_p)
>  	 * Reserve memory for crash kernel after SRAT is parsed so that it
>  	 * won't consume hotpluggable memory.
>  	 */
> -	reserve_crashkernel();
> +	if (xen_pv_domain())
> +		pr_info("Ignoring crashkernel for a Xen PV domain\n");
> +	else {
> +		reserve_crashkernel();
> +#ifdef CONFIG_KEXEC_CORE
> +		if (crashk_res.end > crashk_res.start)
> +			insert_resource(&iomem_resource, &crashk_res);
> +		if (crashk_low_res.end > crashk_low_res.start)
> +			insert_resource(&iomem_resource, &crashk_low_res);
> +#endif

Acked-by: Baoquan He <bhe@redhat.com>

> +	}
>  
>  	memblock_find_dma_reserve();
>  
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-18  6:31     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  6:31 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec,
	kernel test robot

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
> to arch/x86/include/asm/elf.h to fix the following compiling warning:
> 
> make ARCH=i386
> In file included from arch/x86/kernel/setup.c:39:0:
> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> 
> In file included from arch/x86/kernel/setup.c:9:0:
> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>  #define vmcore_elf_check_arch_cross(x) 0
> 
> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
> 
> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
> the warning.
> 
> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")

Where does this commit id '2db65f1db17d' come from? Here you are fixing
another pathc in the same patchset. Please merge this with patch 05/11.

> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/x86/include/asm/elf.h   | 3 +++
>  arch/x86/include/asm/kexec.h | 3 ---
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index 66bdfe838d61..5333777cc758 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>  
>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>  
> +/* We can also handle crash dumps from 64 bit kernel. */
> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> +
>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>     contains a pointer to a function which might be registered using `atexit'.
>     This provides a mean for the dynamic linker to call DT_FINI functions for
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 2b18f918203e..6fcae01a9cca 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -72,9 +72,6 @@ struct kimage;
>  
>  /* The native architecture */
>  # define KEXEC_ARCH KEXEC_ARCH_386
> -
> -/* We can also handle crash dumps from 64 bit kernel. */
> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>  #else
>  /* Maximum physical address we can use pages from */
>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-02-18  6:31     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  6:31 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, kernel test robot, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
> to arch/x86/include/asm/elf.h to fix the following compiling warning:
> 
> make ARCH=i386
> In file included from arch/x86/kernel/setup.c:39:0:
> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> 
> In file included from arch/x86/kernel/setup.c:9:0:
> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>  #define vmcore_elf_check_arch_cross(x) 0
> 
> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
> 
> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
> the warning.
> 
> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")

Where does this commit id '2db65f1db17d' come from? Here you are fixing
another pathc in the same patchset. Please merge this with patch 05/11.

> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/x86/include/asm/elf.h   | 3 +++
>  arch/x86/include/asm/kexec.h | 3 ---
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index 66bdfe838d61..5333777cc758 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>  
>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>  
> +/* We can also handle crash dumps from 64 bit kernel. */
> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> +
>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>     contains a pointer to a function which might be registered using `atexit'.
>     This provides a mean for the dynamic linker to call DT_FINI functions for
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 2b18f918203e..6fcae01a9cca 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -72,9 +72,6 @@ struct kimage;
>  
>  /* The native architecture */
>  # define KEXEC_ARCH KEXEC_ARCH_386
> -
> -/* We can also handle crash dumps from 64 bit kernel. */
> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>  #else
>  /* Maximum physical address we can use pages from */
>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-02-18  6:31     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  6:31 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, kernel test robot, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
> to arch/x86/include/asm/elf.h to fix the following compiling warning:
> 
> make ARCH=i386
> In file included from arch/x86/kernel/setup.c:39:0:
> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> 
> In file included from arch/x86/kernel/setup.c:9:0:
> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>  #define vmcore_elf_check_arch_cross(x) 0
> 
> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
> 
> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
> the warning.
> 
> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")

Where does this commit id '2db65f1db17d' come from? Here you are fixing
another pathc in the same patchset. Please merge this with patch 05/11.

> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/x86/include/asm/elf.h   | 3 +++
>  arch/x86/include/asm/kexec.h | 3 ---
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index 66bdfe838d61..5333777cc758 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>  
>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>  
> +/* We can also handle crash dumps from 64 bit kernel. */
> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
> +
>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>     contains a pointer to a function which might be registered using `atexit'.
>     This provides a mean for the dynamic linker to call DT_FINI functions for
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 2b18f918203e..6fcae01a9cca 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -72,9 +72,6 @@ struct kimage;
>  
>  /* The native architecture */
>  # define KEXEC_ARCH KEXEC_ARCH_386
> -
> -/* We can also handle crash dumps from 64 bit kernel. */
> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>  #else
>  /* Maximum physical address we can use pages from */
>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
> -- 
> 2.20.1
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
  2021-02-18  6:31     ` Baoquan He
  (?)
@ 2021-02-18  7:05       ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-18  7:05 UTC (permalink / raw)
  To: Baoquan He
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec,
	kernel test robot



On 2021/2/18 14:31, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
>> to arch/x86/include/asm/elf.h to fix the following compiling warning:
>>
>> make ARCH=i386
>> In file included from arch/x86/kernel/setup.c:39:0:
>> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>
>> In file included from arch/x86/kernel/setup.c:9:0:
>> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>>  #define vmcore_elf_check_arch_cross(x) 0
>>
>> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
>> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
>> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
>>
>> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
>> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
>> the warning.
>>
>> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
> Where does this commit id '2db65f1db17d' come from? Here you are fixing
> another pathc in the same patchset. Please merge this with patch 05/11.
Yeah, the commit id is invalid, i will merge this patch with patch 05/11.

Thanks,
Chen Zhou
>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/x86/include/asm/elf.h   | 3 +++
>>  arch/x86/include/asm/kexec.h | 3 ---
>>  2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
>> index 66bdfe838d61..5333777cc758 100644
>> --- a/arch/x86/include/asm/elf.h
>> +++ b/arch/x86/include/asm/elf.h
>> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>>  
>>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>>  
>> +/* We can also handle crash dumps from 64 bit kernel. */
>> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>> +
>>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>>     contains a pointer to a function which might be registered using `atexit'.
>>     This provides a mean for the dynamic linker to call DT_FINI functions for
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 2b18f918203e..6fcae01a9cca 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -72,9 +72,6 @@ struct kimage;
>>  
>>  /* The native architecture */
>>  # define KEXEC_ARCH KEXEC_ARCH_386
>> -
>> -/* We can also handle crash dumps from 64 bit kernel. */
>> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>  #else
>>  /* Maximum physical address we can use pages from */
>>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
>> -- 
>> 2.20.1
>>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-02-18  7:05       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-18  7:05 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, kernel test robot, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne



On 2021/2/18 14:31, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
>> to arch/x86/include/asm/elf.h to fix the following compiling warning:
>>
>> make ARCH=i386
>> In file included from arch/x86/kernel/setup.c:39:0:
>> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>
>> In file included from arch/x86/kernel/setup.c:9:0:
>> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>>  #define vmcore_elf_check_arch_cross(x) 0
>>
>> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
>> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
>> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
>>
>> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
>> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
>> the warning.
>>
>> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
> Where does this commit id '2db65f1db17d' come from? Here you are fixing
> another pathc in the same patchset. Please merge this with patch 05/11.
Yeah, the commit id is invalid, i will merge this patch with patch 05/11.

Thanks,
Chen Zhou
>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/x86/include/asm/elf.h   | 3 +++
>>  arch/x86/include/asm/kexec.h | 3 ---
>>  2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
>> index 66bdfe838d61..5333777cc758 100644
>> --- a/arch/x86/include/asm/elf.h
>> +++ b/arch/x86/include/asm/elf.h
>> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>>  
>>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>>  
>> +/* We can also handle crash dumps from 64 bit kernel. */
>> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>> +
>>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>>     contains a pointer to a function which might be registered using `atexit'.
>>     This provides a mean for the dynamic linker to call DT_FINI functions for
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 2b18f918203e..6fcae01a9cca 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -72,9 +72,6 @@ struct kimage;
>>  
>>  /* The native architecture */
>>  # define KEXEC_ARCH KEXEC_ARCH_386
>> -
>> -/* We can also handle crash dumps from 64 bit kernel. */
>> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>  #else
>>  /* Maximum physical address we can use pages from */
>>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h
@ 2021-02-18  7:05       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-18  7:05 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, kernel test robot, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne



On 2021/2/18 14:31, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> Move macro vmcore_elf_check_arch_cross from arch/x86/include/asm/kexec.h
>> to arch/x86/include/asm/elf.h to fix the following compiling warning:
>>
>> make ARCH=i386
>> In file included from arch/x86/kernel/setup.c:39:0:
>> ./arch/x86/include/asm/kexec.h:77:0: warning: "vmcore_elf_check_arch_cross" redefined
>>  # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>
>> In file included from arch/x86/kernel/setup.c:9:0:
>> ./include/linux/crash_dump.h:39:0: note: this is the location of the previous definition
>>  #define vmcore_elf_check_arch_cross(x) 0
>>
>> The root cause is that vmcore_elf_check_arch_cross under CONFIG_CRASH_CORE
>> depend on CONFIG_KEXEC_CORE. Commit 2db65f1db17d ("x86: kdump: move
>> reserve_crashkernel[_low]() into crash_core.c") triggered the issue.
>>
>> Suggested by Mike, simply move vmcore_elf_check_arch_cross from
>> arch/x86/include/asm/kexec.h to arch/x86/include/asm/elf.h to fix
>> the warning.
>>
>> Fixes: 2db65f1db17d ("x86: kdump: move reserve_crashkernel[_low]() into crash_core.c")
> Where does this commit id '2db65f1db17d' come from? Here you are fixing
> another pathc in the same patchset. Please merge this with patch 05/11.
Yeah, the commit id is invalid, i will merge this patch with patch 05/11.

Thanks,
Chen Zhou
>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/x86/include/asm/elf.h   | 3 +++
>>  arch/x86/include/asm/kexec.h | 3 ---
>>  2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
>> index 66bdfe838d61..5333777cc758 100644
>> --- a/arch/x86/include/asm/elf.h
>> +++ b/arch/x86/include/asm/elf.h
>> @@ -94,6 +94,9 @@ extern unsigned int vdso32_enabled;
>>  
>>  #define elf_check_arch(x)	elf_check_arch_ia32(x)
>>  
>> +/* We can also handle crash dumps from 64 bit kernel. */
>> +# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>> +
>>  /* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
>>     contains a pointer to a function which might be registered using `atexit'.
>>     This provides a mean for the dynamic linker to call DT_FINI functions for
>> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
>> index 2b18f918203e..6fcae01a9cca 100644
>> --- a/arch/x86/include/asm/kexec.h
>> +++ b/arch/x86/include/asm/kexec.h
>> @@ -72,9 +72,6 @@ struct kimage;
>>  
>>  /* The native architecture */
>>  # define KEXEC_ARCH KEXEC_ARCH_386
>> -
>> -/* We can also handle crash dumps from 64 bit kernel. */
>> -# define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
>>  #else
>>  /* Maximum physical address we can use pages from */
>>  # define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-18  7:31     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:31 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: mingo, tglx, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.
> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Why don't you move the dummy reserve_crashkernel() here too?

#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
#ifdef CONFIG_KEXEC_CORE
...
  '...the real crashkernel reservation code...'
...
#else                     
static void __init reserve_crashkernel(void)
{
}                                               
#endif
#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Like this, you don't need those two dummy reserve_crashkernel() in x86
and arm64?

Thanks
Baoquan

>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  7:31     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:31 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: horms, John.P.donnelly, wangkefeng.wang, arnd, will, corbet,
	catalin.marinas, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, linux-arm-kernel, huawei.libin,
	prabhakar.pkin, tglx, dyoung, kexec, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.
> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Why don't you move the dummy reserve_crashkernel() here too?

#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
#ifdef CONFIG_KEXEC_CORE
...
  '...the real crashkernel reservation code...'
...
#else                     
static void __init reserve_crashkernel(void)
{
}                                               
#endif
#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Like this, you don't need those two dummy reserve_crashkernel() in x86
and arm64?

Thanks
Baoquan

>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  7:31     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:31 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: horms, John.P.donnelly, wangkefeng.wang, arnd, will, corbet,
	catalin.marinas, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, linux-arm-kernel, huawei.libin,
	prabhakar.pkin, tglx, dyoung, kexec, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.
> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Why don't you move the dummy reserve_crashkernel() here too?

#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
#ifdef CONFIG_KEXEC_CORE
...
  '...the real crashkernel reservation code...'
...
#else                     
static void __init reserve_crashkernel(void)
{
}                                               
#endif
#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */

Like this, you don't need those two dummy reserve_crashkernel() in x86
and arm64?

Thanks
Baoquan

>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  2021-02-18  7:31     ` Baoquan He
  (?)
@ 2021-02-18  7:40       ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:40 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: mingo, tglx, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 02/18/21 at 03:31pm, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
> > We make the functions reserve_crashkernel[_low]() as generic for
> > x86 and arm64. Since reserve_crashkernel[_low]() implementations
> > are quite similar on other architectures as well, we can have more
> > users of this later.
> > 
> > So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> > select this by X86 and ARM64.
> > 
> > Suggested-by: Mike Rapoport <rppt@kernel.org>
> > Suggested-by: Baoquan He <bhe@redhat.com>
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > ---
> >  arch/Kconfig        | 3 +++
> >  arch/arm64/Kconfig  | 1 +
> >  arch/x86/Kconfig    | 2 ++
> >  kernel/crash_core.c | 7 ++-----
> >  4 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/Kconfig b/arch/Kconfig
> > index 24862d15f3a3..0ca1ff5bb157 100644
> > --- a/arch/Kconfig
> > +++ b/arch/Kconfig
> > @@ -24,6 +24,9 @@ config KEXEC_ELF
> >  config HAVE_IMA_KEXEC
> >  	bool
> >  
> > +config ARCH_WANT_RESERVE_CRASH_KERNEL
> > +	bool
> > +
> >  config SET_FS
> >  	bool
> >  
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index f39568b28ec1..09365c7ff469 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -82,6 +82,7 @@ config ARM64
> >  	select ARCH_WANT_FRAME_POINTERS
> >  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
> >  	select ARCH_WANT_LD_ORPHAN_WARN
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select ARCH_HAS_UBSAN_SANITIZE_ALL
> >  	select ARM_AMBA
> >  	select ARM_ARCH_TIMER
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 21f851179ff0..e6926fcb4a40 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -12,6 +12,7 @@ config X86_32
> >  	depends on !64BIT
> >  	# Options that are inherently 32-bit kernel only:
> >  	select ARCH_WANT_IPC_PARSE_VERSION
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select CLKSRC_I8253
> >  	select CLONE_BACKWARDS
> >  	select GENERIC_VDSO_32
> > @@ -28,6 +29,7 @@ config X86_64
> >  	select ARCH_HAS_GIGANTIC_PAGE
> >  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
> >  	select ARCH_USE_CMPXCHG_LOCKREF
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select HAVE_ARCH_SOFT_DIRTY
> >  	select MODULES_USE_ELF_RELA
> >  	select NEED_DMA_MAP_STATE
> > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > index 8479be270c0b..2c5783985db5 100644
> > --- a/kernel/crash_core.c
> > +++ b/kernel/crash_core.c
> > @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
> >   * --------- Crashkernel reservation ------------------------------
> >   */
> >  
> > -#ifdef CONFIG_KEXEC_CORE
> > -
> > -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> > +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> >  static int __init reserve_crashkernel_low(void)
> >  {
> >  #ifdef CONFIG_64BIT
> > @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
> >  	crashk_res.start = crash_base;
> >  	crashk_res.end   = crash_base + crash_size - 1;
> >  }
> > -#endif
> > -#endif /* CONFIG_KEXEC_CORE */
> > +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Why don't you move the dummy reserve_crashkernel() here too?
> 
> #ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> #ifdef CONFIG_KEXEC_CORE
> ...
>   '...the real crashkernel reservation code...'
> ...
> #else                     
> static void __init reserve_crashkernel(void)
> {
> }                                               
> #endif
> #endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Like this, you don't need those two dummy reserve_crashkernel() in x86
> and arm64?

Sorry, I was wrong. It's impossible like this since
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL is selected only if KEXEC_CORE is
true. Please ignore this comment.


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  7:40       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:40 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: horms, John.P.donnelly, wangkefeng.wang, arnd, will, corbet,
	catalin.marinas, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, linux-arm-kernel, huawei.libin,
	prabhakar.pkin, tglx, dyoung, kexec, nsaenzjulienne

On 02/18/21 at 03:31pm, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
> > We make the functions reserve_crashkernel[_low]() as generic for
> > x86 and arm64. Since reserve_crashkernel[_low]() implementations
> > are quite similar on other architectures as well, we can have more
> > users of this later.
> > 
> > So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> > select this by X86 and ARM64.
> > 
> > Suggested-by: Mike Rapoport <rppt@kernel.org>
> > Suggested-by: Baoquan He <bhe@redhat.com>
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > ---
> >  arch/Kconfig        | 3 +++
> >  arch/arm64/Kconfig  | 1 +
> >  arch/x86/Kconfig    | 2 ++
> >  kernel/crash_core.c | 7 ++-----
> >  4 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/Kconfig b/arch/Kconfig
> > index 24862d15f3a3..0ca1ff5bb157 100644
> > --- a/arch/Kconfig
> > +++ b/arch/Kconfig
> > @@ -24,6 +24,9 @@ config KEXEC_ELF
> >  config HAVE_IMA_KEXEC
> >  	bool
> >  
> > +config ARCH_WANT_RESERVE_CRASH_KERNEL
> > +	bool
> > +
> >  config SET_FS
> >  	bool
> >  
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index f39568b28ec1..09365c7ff469 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -82,6 +82,7 @@ config ARM64
> >  	select ARCH_WANT_FRAME_POINTERS
> >  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
> >  	select ARCH_WANT_LD_ORPHAN_WARN
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select ARCH_HAS_UBSAN_SANITIZE_ALL
> >  	select ARM_AMBA
> >  	select ARM_ARCH_TIMER
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 21f851179ff0..e6926fcb4a40 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -12,6 +12,7 @@ config X86_32
> >  	depends on !64BIT
> >  	# Options that are inherently 32-bit kernel only:
> >  	select ARCH_WANT_IPC_PARSE_VERSION
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select CLKSRC_I8253
> >  	select CLONE_BACKWARDS
> >  	select GENERIC_VDSO_32
> > @@ -28,6 +29,7 @@ config X86_64
> >  	select ARCH_HAS_GIGANTIC_PAGE
> >  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
> >  	select ARCH_USE_CMPXCHG_LOCKREF
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select HAVE_ARCH_SOFT_DIRTY
> >  	select MODULES_USE_ELF_RELA
> >  	select NEED_DMA_MAP_STATE
> > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > index 8479be270c0b..2c5783985db5 100644
> > --- a/kernel/crash_core.c
> > +++ b/kernel/crash_core.c
> > @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
> >   * --------- Crashkernel reservation ------------------------------
> >   */
> >  
> > -#ifdef CONFIG_KEXEC_CORE
> > -
> > -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> > +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> >  static int __init reserve_crashkernel_low(void)
> >  {
> >  #ifdef CONFIG_64BIT
> > @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
> >  	crashk_res.start = crash_base;
> >  	crashk_res.end   = crash_base + crash_size - 1;
> >  }
> > -#endif
> > -#endif /* CONFIG_KEXEC_CORE */
> > +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Why don't you move the dummy reserve_crashkernel() here too?
> 
> #ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> #ifdef CONFIG_KEXEC_CORE
> ...
>   '...the real crashkernel reservation code...'
> ...
> #else                     
> static void __init reserve_crashkernel(void)
> {
> }                                               
> #endif
> #endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Like this, you don't need those two dummy reserve_crashkernel() in x86
> and arm64?

Sorry, I was wrong. It's impossible like this since
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL is selected only if KEXEC_CORE is
true. Please ignore this comment.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  7:40       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  7:40 UTC (permalink / raw)
  To: Chen Zhou, rppt
  Cc: horms, John.P.donnelly, wangkefeng.wang, arnd, will, corbet,
	catalin.marinas, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, linux-arm-kernel, huawei.libin,
	prabhakar.pkin, tglx, dyoung, kexec, nsaenzjulienne

On 02/18/21 at 03:31pm, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
> > We make the functions reserve_crashkernel[_low]() as generic for
> > x86 and arm64. Since reserve_crashkernel[_low]() implementations
> > are quite similar on other architectures as well, we can have more
> > users of this later.
> > 
> > So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> > select this by X86 and ARM64.
> > 
> > Suggested-by: Mike Rapoport <rppt@kernel.org>
> > Suggested-by: Baoquan He <bhe@redhat.com>
> > Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> > ---
> >  arch/Kconfig        | 3 +++
> >  arch/arm64/Kconfig  | 1 +
> >  arch/x86/Kconfig    | 2 ++
> >  kernel/crash_core.c | 7 ++-----
> >  4 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/Kconfig b/arch/Kconfig
> > index 24862d15f3a3..0ca1ff5bb157 100644
> > --- a/arch/Kconfig
> > +++ b/arch/Kconfig
> > @@ -24,6 +24,9 @@ config KEXEC_ELF
> >  config HAVE_IMA_KEXEC
> >  	bool
> >  
> > +config ARCH_WANT_RESERVE_CRASH_KERNEL
> > +	bool
> > +
> >  config SET_FS
> >  	bool
> >  
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index f39568b28ec1..09365c7ff469 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -82,6 +82,7 @@ config ARM64
> >  	select ARCH_WANT_FRAME_POINTERS
> >  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
> >  	select ARCH_WANT_LD_ORPHAN_WARN
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select ARCH_HAS_UBSAN_SANITIZE_ALL
> >  	select ARM_AMBA
> >  	select ARM_ARCH_TIMER
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index 21f851179ff0..e6926fcb4a40 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -12,6 +12,7 @@ config X86_32
> >  	depends on !64BIT
> >  	# Options that are inherently 32-bit kernel only:
> >  	select ARCH_WANT_IPC_PARSE_VERSION
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select CLKSRC_I8253
> >  	select CLONE_BACKWARDS
> >  	select GENERIC_VDSO_32
> > @@ -28,6 +29,7 @@ config X86_64
> >  	select ARCH_HAS_GIGANTIC_PAGE
> >  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
> >  	select ARCH_USE_CMPXCHG_LOCKREF
> > +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
> >  	select HAVE_ARCH_SOFT_DIRTY
> >  	select MODULES_USE_ELF_RELA
> >  	select NEED_DMA_MAP_STATE
> > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > index 8479be270c0b..2c5783985db5 100644
> > --- a/kernel/crash_core.c
> > +++ b/kernel/crash_core.c
> > @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
> >   * --------- Crashkernel reservation ------------------------------
> >   */
> >  
> > -#ifdef CONFIG_KEXEC_CORE
> > -
> > -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> > +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> >  static int __init reserve_crashkernel_low(void)
> >  {
> >  #ifdef CONFIG_64BIT
> > @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
> >  	crashk_res.start = crash_base;
> >  	crashk_res.end   = crash_base + crash_size - 1;
> >  }
> > -#endif
> > -#endif /* CONFIG_KEXEC_CORE */
> > +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Why don't you move the dummy reserve_crashkernel() here too?
> 
> #ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
> #ifdef CONFIG_KEXEC_CORE
> ...
>   '...the real crashkernel reservation code...'
> ...
> #else                     
> static void __init reserve_crashkernel(void)
> {
> }                                               
> #endif
> #endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
> 
> Like this, you don't need those two dummy reserve_crashkernel() in x86
> and arm64?

Sorry, I was wrong. It's impossible like this since
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL is selected only if KEXEC_CORE is
true. Please ignore this comment.


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-18  8:23     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:23 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> To make the functions reserve_crashkernel() as generic,
> replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 27470479e4a3..086a04235be4 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
>  	if (!crash_base) {
>  		/*
>  		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
> -		 * crashkernel=x,high reserves memory over 4G, also allocates
> -		 * 256M extra low memory for DMA buffers and swiotlb.
> +		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
> +		 * also allocates 256M extra low memory for DMA buffers
> +		 * and swiotlb.
>  		 * But the extra memory is not required for all machines.
>  		 * So try low memory first and fall back to high memory
>  		 * unless "crashkernel=size[KMG],high" is specified.
> @@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
>  		}
>  	}
>  
> -	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
> +	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
>  		memblock_free(crash_base, crash_size);
>  		return;

Acked-by: Baoquan He <bhe@redhat.com>

>  	}
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
@ 2021-02-18  8:23     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:23 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> To make the functions reserve_crashkernel() as generic,
> replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 27470479e4a3..086a04235be4 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
>  	if (!crash_base) {
>  		/*
>  		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
> -		 * crashkernel=x,high reserves memory over 4G, also allocates
> -		 * 256M extra low memory for DMA buffers and swiotlb.
> +		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
> +		 * also allocates 256M extra low memory for DMA buffers
> +		 * and swiotlb.
>  		 * But the extra memory is not required for all machines.
>  		 * So try low memory first and fall back to high memory
>  		 * unless "crashkernel=size[KMG],high" is specified.
> @@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
>  		}
>  	}
>  
> -	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
> +	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
>  		memblock_free(crash_base, crash_size);
>  		return;

Acked-by: Baoquan He <bhe@redhat.com>

>  	}
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel()
@ 2021-02-18  8:23     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:23 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> To make the functions reserve_crashkernel() as generic,
> replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.
> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  arch/x86/kernel/setup.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 27470479e4a3..086a04235be4 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -487,8 +487,9 @@ static void __init reserve_crashkernel(void)
>  	if (!crash_base) {
>  		/*
>  		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
> -		 * crashkernel=x,high reserves memory over 4G, also allocates
> -		 * 256M extra low memory for DMA buffers and swiotlb.
> +		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
> +		 * also allocates 256M extra low memory for DMA buffers
> +		 * and swiotlb.
>  		 * But the extra memory is not required for all machines.
>  		 * So try low memory first and fall back to high memory
>  		 * unless "crashkernel=size[KMG],high" is specified.
> @@ -516,7 +517,7 @@ static void __init reserve_crashkernel(void)
>  		}
>  	}
>  
> -	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
> +	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
>  		memblock_free(crash_base, crash_size);
>  		return;

Acked-by: Baoquan He <bhe@redhat.com>

>  	}
> -- 
> 2.20.1
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-18  8:35     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.

This looks much better with the help of
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
option.

And the two dummy function reserve_crashkernel() in x86 and arm64 looks
not so good, but I don't have better idea. Maybe add
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
reserve_crashkernel() in each ARCH? Or just leave with it for now if no
other people has concern or suggestion about it.

Anyway, ack this one.

Acked-by: Baoquan He <bhe@redhat.com>

Thanks
Baoquan


> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  8:35     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.

This looks much better with the help of
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
option.

And the two dummy function reserve_crashkernel() in x86 and arm64 looks
not so good, but I don't have better idea. Maybe add
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
reserve_crashkernel() in each ARCH? Or just leave with it for now if no
other people has concern or suggestion about it.

Anyway, ack this one.

Acked-by: Baoquan He <bhe@redhat.com>

Thanks
Baoquan


> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-18  8:35     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> We make the functions reserve_crashkernel[_low]() as generic for
> x86 and arm64. Since reserve_crashkernel[_low]() implementations
> are quite similar on other architectures as well, we can have more
> users of this later.
> 
> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
> select this by X86 and ARM64.

This looks much better with the help of
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
option.

And the two dummy function reserve_crashkernel() in x86 and arm64 looks
not so good, but I don't have better idea. Maybe add
CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
reserve_crashkernel() in each ARCH? Or just leave with it for now if no
other people has concern or suggestion about it.

Anyway, ack this one.

Acked-by: Baoquan He <bhe@redhat.com>

Thanks
Baoquan


> 
> Suggested-by: Mike Rapoport <rppt@kernel.org>
> Suggested-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> ---
>  arch/Kconfig        | 3 +++
>  arch/arm64/Kconfig  | 1 +
>  arch/x86/Kconfig    | 2 ++
>  kernel/crash_core.c | 7 ++-----
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 24862d15f3a3..0ca1ff5bb157 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -24,6 +24,9 @@ config KEXEC_ELF
>  config HAVE_IMA_KEXEC
>  	bool
>  
> +config ARCH_WANT_RESERVE_CRASH_KERNEL
> +	bool
> +
>  config SET_FS
>  	bool
>  
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index f39568b28ec1..09365c7ff469 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -82,6 +82,7 @@ config ARM64
>  	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>  	select ARCH_WANT_LD_ORPHAN_WARN
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>  	select ARM_AMBA
>  	select ARM_ARCH_TIMER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 21f851179ff0..e6926fcb4a40 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -12,6 +12,7 @@ config X86_32
>  	depends on !64BIT
>  	# Options that are inherently 32-bit kernel only:
>  	select ARCH_WANT_IPC_PARSE_VERSION
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
>  	select GENERIC_VDSO_32
> @@ -28,6 +29,7 @@ config X86_64
>  	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>  	select HAVE_ARCH_SOFT_DIRTY
>  	select MODULES_USE_ELF_RELA
>  	select NEED_DMA_MAP_STATE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 8479be270c0b..2c5783985db5 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>   * --------- Crashkernel reservation ------------------------------
>   */
>  
> -#ifdef CONFIG_KEXEC_CORE
> -
> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>  static int __init reserve_crashkernel_low(void)
>  {
>  #ifdef CONFIG_64BIT
> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>  	crashk_res.start = crash_base;
>  	crashk_res.end   = crash_base + crash_size - 1;
>  }
> -#endif
> -#endif /* CONFIG_KEXEC_CORE */
> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>  
>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>  			  void *data, size_t data_len)
> -- 
> 2.20.1
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-18  8:40     ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:40 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> For arm64, the behavior of crashkernel=X has been changed, which
> tries low allocation in DMA zone and fall back to high allocation
> if it fails.
> 
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
> 
> So update the Documentation.

Nice document adding which also takes care of x86 code implementation,
thanks. By the way, maybe you can remove John's 'Tested-by' since it
doesn't make much sense to test a document patch.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
> index 75a9dd98e76e..0877c76f8015 100644
> --- a/Documentation/admin-guide/kdump/kdump.rst
> +++ b/Documentation/admin-guide/kdump/kdump.rst
> @@ -299,7 +299,16 @@ Boot into System Kernel
>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>  
> -   On x86 and x86_64, use "crashkernel=64M@16M".
> +   On x86 use "crashkernel=64M@16M".
> +
> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
> +   fall back to reserve region above 4G. And go for high allocation
> +   directly if the required size is too large.
> +   We can also use "crashkernel=X,high" to select a region above 4G, which
> +   also tries to allocate at least 256M below 4G automatically and
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
> +   start address X.
>  
>     On ppc64, use "crashkernel=128M@32M".
>  
> @@ -316,8 +325,15 @@ Boot into System Kernel
>     kernel will automatically locate the crash kernel image within the
>     first 512MB of RAM if X is not given.
>  
> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
> +   fall back to high allocation if it fails.
> +   We can also use "crashkernel=X,high" to select a high region above
> +   DMA zone, which also tries to allocate at least 256M low memory in
> +   DMA zone automatically.
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from
> +   specified start address X. Note that the start address of the kernel,
> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>  
>  Load the Dump-capture Kernel
>  ============================
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.
> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.
> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.
>  	cryptomgr.notests
>  			[KNL] Disable crypto self-tests
>  
> -- 
> 2.20.1
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-18  8:40     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:40 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> For arm64, the behavior of crashkernel=X has been changed, which
> tries low allocation in DMA zone and fall back to high allocation
> if it fails.
> 
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
> 
> So update the Documentation.

Nice document adding which also takes care of x86 code implementation,
thanks. By the way, maybe you can remove John's 'Tested-by' since it
doesn't make much sense to test a document patch.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
> index 75a9dd98e76e..0877c76f8015 100644
> --- a/Documentation/admin-guide/kdump/kdump.rst
> +++ b/Documentation/admin-guide/kdump/kdump.rst
> @@ -299,7 +299,16 @@ Boot into System Kernel
>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>  
> -   On x86 and x86_64, use "crashkernel=64M@16M".
> +   On x86 use "crashkernel=64M@16M".
> +
> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
> +   fall back to reserve region above 4G. And go for high allocation
> +   directly if the required size is too large.
> +   We can also use "crashkernel=X,high" to select a region above 4G, which
> +   also tries to allocate at least 256M below 4G automatically and
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
> +   start address X.
>  
>     On ppc64, use "crashkernel=128M@32M".
>  
> @@ -316,8 +325,15 @@ Boot into System Kernel
>     kernel will automatically locate the crash kernel image within the
>     first 512MB of RAM if X is not given.
>  
> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
> +   fall back to high allocation if it fails.
> +   We can also use "crashkernel=X,high" to select a high region above
> +   DMA zone, which also tries to allocate at least 256M low memory in
> +   DMA zone automatically.
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from
> +   specified start address X. Note that the start address of the kernel,
> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>  
>  Load the Dump-capture Kernel
>  ============================
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.
> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.
> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.
>  	cryptomgr.notests
>  			[KNL] Disable crypto self-tests
>  
> -- 
> 2.20.1
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-18  8:40     ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-18  8:40 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 01/30/21 at 03:10pm, Chen Zhou wrote:
> For arm64, the behavior of crashkernel=X has been changed, which
> tries low allocation in DMA zone and fall back to high allocation
> if it fails.
> 
> We can also use "crashkernel=X,high" to select a high region above
> DMA zone, which also tries to allocate at least 256M low memory in
> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
> specified size low memory.
> 
> So update the Documentation.

Nice document adding which also takes care of x86 code implementation,
thanks. By the way, maybe you can remove John's 'Tested-by' since it
doesn't make much sense to test a document patch.

Acked-by: Baoquan He <bhe@redhat.com>

> 
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
> ---
>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>  2 files changed, 28 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
> index 75a9dd98e76e..0877c76f8015 100644
> --- a/Documentation/admin-guide/kdump/kdump.rst
> +++ b/Documentation/admin-guide/kdump/kdump.rst
> @@ -299,7 +299,16 @@ Boot into System Kernel
>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>  
> -   On x86 and x86_64, use "crashkernel=64M@16M".
> +   On x86 use "crashkernel=64M@16M".
> +
> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
> +   fall back to reserve region above 4G. And go for high allocation
> +   directly if the required size is too large.
> +   We can also use "crashkernel=X,high" to select a region above 4G, which
> +   also tries to allocate at least 256M below 4G automatically and
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
> +   start address X.
>  
>     On ppc64, use "crashkernel=128M@32M".
>  
> @@ -316,8 +325,15 @@ Boot into System Kernel
>     kernel will automatically locate the crash kernel image within the
>     first 512MB of RAM if X is not given.
>  
> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
> +   fall back to high allocation if it fails.
> +   We can also use "crashkernel=X,high" to select a high region above
> +   DMA zone, which also tries to allocate at least 256M low memory in
> +   DMA zone automatically.
> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
> +   Use "crashkernel=Y@X" if you really have to reserve memory from
> +   specified start address X. Note that the start address of the kernel,
> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>  
>  Load the Dump-capture Kernel
>  ============================
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index a10b545c2070..908e5c8b61ba 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -738,6 +738,9 @@
>  			[KNL, X86-64] Select a region under 4G first, and
>  			fall back to reserve region above 4G when '@offset'
>  			hasn't been specified.
> +			[KNL, arm64] Try low allocation in DMA zone and fall back
> +			to high allocation if it fails when '@offset' hasn't been
> +			specified.
>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>  
>  	crashkernel=range1:size1[,range2:size2,...][@offset]
> @@ -754,6 +757,8 @@
>  			Otherwise memory region will be allocated below 4G, if
>  			available.
>  			It will be ignored if crashkernel=X is specified.
> +			[KNL, arm64] range in high memory.
> +			Allow kernel to allocate physical memory region from top.
>  	crashkernel=size[KMG],low
>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>  			is passed, kernel could allocate physical memory region
> @@ -762,13 +767,15 @@
>  			requires at least 64M+32K low memory, also enough extra
>  			low memory is needed to make sure DMA buffers for 32-bit
>  			devices won't run out. Kernel would try to allocate at
> -			at least 256M below 4G automatically.
> +			least 256M below 4G automatically.
>  			This one let user to specify own low range under 4G
>  			for second kernel instead.
>  			0: to disable low allocation.
>  			It will be ignored when crashkernel=X,high is not used
>  			or memory reserved is below 4G.
> -
> +			[KNL, arm64] range in low memory.
> +			This one let user to specify a low range in DMA zone for
> +			crash dump kernel.
>  	cryptomgr.notests
>  			[KNL] Disable crypto self-tests
>  
> -- 
> 2.20.1
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
  2021-02-18  8:35     ` Baoquan He
  (?)
@ 2021-02-20  3:22       ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:22 UTC (permalink / raw)
  To: Baoquan He
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/18 16:35, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> We make the functions reserve_crashkernel[_low]() as generic for
>> x86 and arm64. Since reserve_crashkernel[_low]() implementations
>> are quite similar on other architectures as well, we can have more
>> users of this later.
>>
>> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
>> select this by X86 and ARM64.
> This looks much better with the help of
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
> 'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
> CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
> option.
OK, i will delete this.
>
> And the two dummy function reserve_crashkernel() in x86 and arm64 looks
> not so good, but I don't have better idea. Maybe add
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
> reserve_crashkernel() in each ARCH? Or just leave with it for now if no
> other people has concern or suggestion about it.
>
> Anyway, ack this one.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
> Thanks
> Baoquan
>
>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Suggested-by: Baoquan He <bhe@redhat.com>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/Kconfig        | 3 +++
>>  arch/arm64/Kconfig  | 1 +
>>  arch/x86/Kconfig    | 2 ++
>>  kernel/crash_core.c | 7 ++-----
>>  4 files changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index 24862d15f3a3..0ca1ff5bb157 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -24,6 +24,9 @@ config KEXEC_ELF
>>  config HAVE_IMA_KEXEC
>>  	bool
>>  
>> +config ARCH_WANT_RESERVE_CRASH_KERNEL
>> +	bool
>> +
>>  config SET_FS
>>  	bool
>>  
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index f39568b28ec1..09365c7ff469 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -82,6 +82,7 @@ config ARM64
>>  	select ARCH_WANT_FRAME_POINTERS
>>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>>  	select ARCH_WANT_LD_ORPHAN_WARN
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>>  	select ARM_AMBA
>>  	select ARM_ARCH_TIMER
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index 21f851179ff0..e6926fcb4a40 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -12,6 +12,7 @@ config X86_32
>>  	depends on !64BIT
>>  	# Options that are inherently 32-bit kernel only:
>>  	select ARCH_WANT_IPC_PARSE_VERSION
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select CLKSRC_I8253
>>  	select CLONE_BACKWARDS
>>  	select GENERIC_VDSO_32
>> @@ -28,6 +29,7 @@ config X86_64
>>  	select ARCH_HAS_GIGANTIC_PAGE
>>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>>  	select ARCH_USE_CMPXCHG_LOCKREF
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select HAVE_ARCH_SOFT_DIRTY
>>  	select MODULES_USE_ELF_RELA
>>  	select NEED_DMA_MAP_STATE
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 8479be270c0b..2c5783985db5 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>>   * --------- Crashkernel reservation ------------------------------
>>   */
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -
>> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
>> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>>  static int __init reserve_crashkernel_low(void)
>>  {
>>  #ifdef CONFIG_64BIT
>> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>>  	crashk_res.start = crash_base;
>>  	crashk_res.end   = crash_base + crash_size - 1;
>>  }
>> -#endif
>> -#endif /* CONFIG_KEXEC_CORE */
>> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>>  
>>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>>  			  void *data, size_t data_len)
>> -- 
>> 2.20.1
>>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-20  3:22       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:22 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne



On 2021/2/18 16:35, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> We make the functions reserve_crashkernel[_low]() as generic for
>> x86 and arm64. Since reserve_crashkernel[_low]() implementations
>> are quite similar on other architectures as well, we can have more
>> users of this later.
>>
>> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
>> select this by X86 and ARM64.
> This looks much better with the help of
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
> 'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
> CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
> option.
OK, i will delete this.
>
> And the two dummy function reserve_crashkernel() in x86 and arm64 looks
> not so good, but I don't have better idea. Maybe add
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
> reserve_crashkernel() in each ARCH? Or just leave with it for now if no
> other people has concern or suggestion about it.
>
> Anyway, ack this one.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
> Thanks
> Baoquan
>
>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Suggested-by: Baoquan He <bhe@redhat.com>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/Kconfig        | 3 +++
>>  arch/arm64/Kconfig  | 1 +
>>  arch/x86/Kconfig    | 2 ++
>>  kernel/crash_core.c | 7 ++-----
>>  4 files changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index 24862d15f3a3..0ca1ff5bb157 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -24,6 +24,9 @@ config KEXEC_ELF
>>  config HAVE_IMA_KEXEC
>>  	bool
>>  
>> +config ARCH_WANT_RESERVE_CRASH_KERNEL
>> +	bool
>> +
>>  config SET_FS
>>  	bool
>>  
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index f39568b28ec1..09365c7ff469 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -82,6 +82,7 @@ config ARM64
>>  	select ARCH_WANT_FRAME_POINTERS
>>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>>  	select ARCH_WANT_LD_ORPHAN_WARN
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>>  	select ARM_AMBA
>>  	select ARM_ARCH_TIMER
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index 21f851179ff0..e6926fcb4a40 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -12,6 +12,7 @@ config X86_32
>>  	depends on !64BIT
>>  	# Options that are inherently 32-bit kernel only:
>>  	select ARCH_WANT_IPC_PARSE_VERSION
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select CLKSRC_I8253
>>  	select CLONE_BACKWARDS
>>  	select GENERIC_VDSO_32
>> @@ -28,6 +29,7 @@ config X86_64
>>  	select ARCH_HAS_GIGANTIC_PAGE
>>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>>  	select ARCH_USE_CMPXCHG_LOCKREF
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select HAVE_ARCH_SOFT_DIRTY
>>  	select MODULES_USE_ELF_RELA
>>  	select NEED_DMA_MAP_STATE
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 8479be270c0b..2c5783985db5 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>>   * --------- Crashkernel reservation ------------------------------
>>   */
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -
>> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
>> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>>  static int __init reserve_crashkernel_low(void)
>>  {
>>  #ifdef CONFIG_64BIT
>> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>>  	crashk_res.start = crash_base;
>>  	crashk_res.end   = crash_base + crash_size - 1;
>>  }
>> -#endif
>> -#endif /* CONFIG_KEXEC_CORE */
>> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>>  
>>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>>  			  void *data, size_t data_len)
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config
@ 2021-02-20  3:22       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:22 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne



On 2021/2/18 16:35, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> We make the functions reserve_crashkernel[_low]() as generic for
>> x86 and arm64. Since reserve_crashkernel[_low]() implementations
>> are quite similar on other architectures as well, we can have more
>> users of this later.
>>
>> So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
>> select this by X86 and ARM64.
> This looks much better with the help of
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL. And please take off the
> 'Suggested-by' tag from me, I just don't like the old CONFIG_X86 and
> CONFIG_ARM64 ifdeffery way in v13, Mike suggested this ARCH_WANT_
> option.
OK, i will delete this.
>
> And the two dummy function reserve_crashkernel() in x86 and arm64 looks
> not so good, but I don't have better idea. Maybe add
> CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL iddeffery in the call site of
> reserve_crashkernel() in each ARCH? Or just leave with it for now if no
> other people has concern or suggestion about it.
>
> Anyway, ack this one.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
> Thanks
> Baoquan
>
>
>> Suggested-by: Mike Rapoport <rppt@kernel.org>
>> Suggested-by: Baoquan He <bhe@redhat.com>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
>>  arch/Kconfig        | 3 +++
>>  arch/arm64/Kconfig  | 1 +
>>  arch/x86/Kconfig    | 2 ++
>>  kernel/crash_core.c | 7 ++-----
>>  4 files changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index 24862d15f3a3..0ca1ff5bb157 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -24,6 +24,9 @@ config KEXEC_ELF
>>  config HAVE_IMA_KEXEC
>>  	bool
>>  
>> +config ARCH_WANT_RESERVE_CRASH_KERNEL
>> +	bool
>> +
>>  config SET_FS
>>  	bool
>>  
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index f39568b28ec1..09365c7ff469 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -82,6 +82,7 @@ config ARM64
>>  	select ARCH_WANT_FRAME_POINTERS
>>  	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
>>  	select ARCH_WANT_LD_ORPHAN_WARN
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select ARCH_HAS_UBSAN_SANITIZE_ALL
>>  	select ARM_AMBA
>>  	select ARM_ARCH_TIMER
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index 21f851179ff0..e6926fcb4a40 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -12,6 +12,7 @@ config X86_32
>>  	depends on !64BIT
>>  	# Options that are inherently 32-bit kernel only:
>>  	select ARCH_WANT_IPC_PARSE_VERSION
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select CLKSRC_I8253
>>  	select CLONE_BACKWARDS
>>  	select GENERIC_VDSO_32
>> @@ -28,6 +29,7 @@ config X86_64
>>  	select ARCH_HAS_GIGANTIC_PAGE
>>  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
>>  	select ARCH_USE_CMPXCHG_LOCKREF
>> +	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
>>  	select HAVE_ARCH_SOFT_DIRTY
>>  	select MODULES_USE_ELF_RELA
>>  	select NEED_DMA_MAP_STATE
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 8479be270c0b..2c5783985db5 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
>>   * --------- Crashkernel reservation ------------------------------
>>   */
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -
>> -#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
>> +#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
>>  static int __init reserve_crashkernel_low(void)
>>  {
>>  #ifdef CONFIG_64BIT
>> @@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
>>  	crashk_res.start = crash_base;
>>  	crashk_res.end   = crash_base + crash_size - 1;
>>  }
>> -#endif
>> -#endif /* CONFIG_KEXEC_CORE */
>> +#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
>>  
>>  Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
>>  			  void *data, size_t data_len)
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
  2021-02-18  8:40     ` Baoquan He
  (?)
@ 2021-02-20  3:25       ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:25 UTC (permalink / raw)
  To: Baoquan He
  Cc: mingo, tglx, rppt, dyoung, catalin.marinas, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/18 16:40, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> For arm64, the behavior of crashkernel=X has been changed, which
>> tries low allocation in DMA zone and fall back to high allocation
>> if it fails.
>>
>> We can also use "crashkernel=X,high" to select a high region above
>> DMA zone, which also tries to allocate at least 256M low memory in
>> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
>> specified size low memory.
>>
>> So update the Documentation.
> Nice document adding which also takes care of x86 code implementation,
> thanks. By the way, maybe you can remove John's 'Tested-by' since it
> doesn't make much sense to test a document patch.
I will remove the Tested-by in next version.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
>> index 75a9dd98e76e..0877c76f8015 100644
>> --- a/Documentation/admin-guide/kdump/kdump.rst
>> +++ b/Documentation/admin-guide/kdump/kdump.rst
>> @@ -299,7 +299,16 @@ Boot into System Kernel
>>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>>  
>> -   On x86 and x86_64, use "crashkernel=64M@16M".
>> +   On x86 use "crashkernel=64M@16M".
>> +
>> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
>> +   fall back to reserve region above 4G. And go for high allocation
>> +   directly if the required size is too large.
>> +   We can also use "crashkernel=X,high" to select a region above 4G, which
>> +   also tries to allocate at least 256M below 4G automatically and
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
>> +   start address X.
>>  
>>     On ppc64, use "crashkernel=128M@32M".
>>  
>> @@ -316,8 +325,15 @@ Boot into System Kernel
>>     kernel will automatically locate the crash kernel image within the
>>     first 512MB of RAM if X is not given.
>>  
>> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
>> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
>> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
>> +   fall back to high allocation if it fails.
>> +   We can also use "crashkernel=X,high" to select a high region above
>> +   DMA zone, which also tries to allocate at least 256M low memory in
>> +   DMA zone automatically.
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from
>> +   specified start address X. Note that the start address of the kernel,
>> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>>  
>>  Load the Dump-capture Kernel
>>  ============================
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>>  	cryptomgr.notests
>>  			[KNL] Disable crypto self-tests
>>  
>> -- 
>> 2.20.1
>>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-20  3:25       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:25 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne



On 2021/2/18 16:40, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> For arm64, the behavior of crashkernel=X has been changed, which
>> tries low allocation in DMA zone and fall back to high allocation
>> if it fails.
>>
>> We can also use "crashkernel=X,high" to select a high region above
>> DMA zone, which also tries to allocate at least 256M low memory in
>> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
>> specified size low memory.
>>
>> So update the Documentation.
> Nice document adding which also takes care of x86 code implementation,
> thanks. By the way, maybe you can remove John's 'Tested-by' since it
> doesn't make much sense to test a document patch.
I will remove the Tested-by in next version.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
>> index 75a9dd98e76e..0877c76f8015 100644
>> --- a/Documentation/admin-guide/kdump/kdump.rst
>> +++ b/Documentation/admin-guide/kdump/kdump.rst
>> @@ -299,7 +299,16 @@ Boot into System Kernel
>>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>>  
>> -   On x86 and x86_64, use "crashkernel=64M@16M".
>> +   On x86 use "crashkernel=64M@16M".
>> +
>> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
>> +   fall back to reserve region above 4G. And go for high allocation
>> +   directly if the required size is too large.
>> +   We can also use "crashkernel=X,high" to select a region above 4G, which
>> +   also tries to allocate at least 256M below 4G automatically and
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
>> +   start address X.
>>  
>>     On ppc64, use "crashkernel=128M@32M".
>>  
>> @@ -316,8 +325,15 @@ Boot into System Kernel
>>     kernel will automatically locate the crash kernel image within the
>>     first 512MB of RAM if X is not given.
>>  
>> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
>> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
>> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
>> +   fall back to high allocation if it fails.
>> +   We can also use "crashkernel=X,high" to select a high region above
>> +   DMA zone, which also tries to allocate at least 256M low memory in
>> +   DMA zone automatically.
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from
>> +   specified start address X. Note that the start address of the kernel,
>> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>>  
>>  Load the Dump-capture Kernel
>>  ============================
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>>  	cryptomgr.notests
>>  			[KNL] Disable crypto self-tests
>>  
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 11/11] kdump: update Documentation about crashkernel
@ 2021-02-20  3:25       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-20  3:25 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, catalin.marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne



On 2021/2/18 16:40, Baoquan He wrote:
> On 01/30/21 at 03:10pm, Chen Zhou wrote:
>> For arm64, the behavior of crashkernel=X has been changed, which
>> tries low allocation in DMA zone and fall back to high allocation
>> if it fails.
>>
>> We can also use "crashkernel=X,high" to select a high region above
>> DMA zone, which also tries to allocate at least 256M low memory in
>> DMA zone automatically and "crashkernel=Y,low" can be used to allocate
>> specified size low memory.
>>
>> So update the Documentation.
> Nice document adding which also takes care of x86 code implementation,
> thanks. By the way, maybe you can remove John's 'Tested-by' since it
> doesn't make much sense to test a document patch.
I will remove the Tested-by in next version.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> Tested-by: John Donnelly <John.p.donnelly@oracle.com>
>> ---
>>  Documentation/admin-guide/kdump/kdump.rst     | 22 ++++++++++++++++---
>>  .../admin-guide/kernel-parameters.txt         | 11 ++++++++--
>>  2 files changed, 28 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst
>> index 75a9dd98e76e..0877c76f8015 100644
>> --- a/Documentation/admin-guide/kdump/kdump.rst
>> +++ b/Documentation/admin-guide/kdump/kdump.rst
>> @@ -299,7 +299,16 @@ Boot into System Kernel
>>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>>  
>> -   On x86 and x86_64, use "crashkernel=64M@16M".
>> +   On x86 use "crashkernel=64M@16M".
>> +
>> +   On x86_64, use "crashkernel=X" to select a region under 4G first, and
>> +   fall back to reserve region above 4G. And go for high allocation
>> +   directly if the required size is too large.
>> +   We can also use "crashkernel=X,high" to select a region above 4G, which
>> +   also tries to allocate at least 256M below 4G automatically and
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from specified
>> +   start address X.
>>  
>>     On ppc64, use "crashkernel=128M@32M".
>>  
>> @@ -316,8 +325,15 @@ Boot into System Kernel
>>     kernel will automatically locate the crash kernel image within the
>>     first 512MB of RAM if X is not given.
>>  
>> -   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
>> -   the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
>> +   On arm64, use "crashkernel=X" to try low allocation in DMA zone and
>> +   fall back to high allocation if it fails.
>> +   We can also use "crashkernel=X,high" to select a high region above
>> +   DMA zone, which also tries to allocate at least 256M low memory in
>> +   DMA zone automatically.
>> +   "crashkernel=Y,low" can be used to allocate specified size low memory.
>> +   Use "crashkernel=Y@X" if you really have to reserve memory from
>> +   specified start address X. Note that the start address of the kernel,
>> +   X if explicitly specified, must be aligned to 2MiB (0x200000).
>>  
>>  Load the Dump-capture Kernel
>>  ============================
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index a10b545c2070..908e5c8b61ba 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -738,6 +738,9 @@
>>  			[KNL, X86-64] Select a region under 4G first, and
>>  			fall back to reserve region above 4G when '@offset'
>>  			hasn't been specified.
>> +			[KNL, arm64] Try low allocation in DMA zone and fall back
>> +			to high allocation if it fails when '@offset' hasn't been
>> +			specified.
>>  			See Documentation/admin-guide/kdump/kdump.rst for further details.
>>  
>>  	crashkernel=range1:size1[,range2:size2,...][@offset]
>> @@ -754,6 +757,8 @@
>>  			Otherwise memory region will be allocated below 4G, if
>>  			available.
>>  			It will be ignored if crashkernel=X is specified.
>> +			[KNL, arm64] range in high memory.
>> +			Allow kernel to allocate physical memory region from top.
>>  	crashkernel=size[KMG],low
>>  			[KNL, X86-64] range under 4G. When crashkernel=X,high
>>  			is passed, kernel could allocate physical memory region
>> @@ -762,13 +767,15 @@
>>  			requires at least 64M+32K low memory, also enough extra
>>  			low memory is needed to make sure DMA buffers for 32-bit
>>  			devices won't run out. Kernel would try to allocate at
>> -			at least 256M below 4G automatically.
>> +			least 256M below 4G automatically.
>>  			This one let user to specify own low range under 4G
>>  			for second kernel instead.
>>  			0: to disable low allocation.
>>  			It will be ignored when crashkernel=X,high is not used
>>  			or memory reserved is below 4G.
>> -
>> +			[KNL, arm64] range in low memory.
>> +			This one let user to specify a low range in DMA zone for
>> +			crash dump kernel.
>>  	cryptomgr.notests
>>  			[KNL] Disable crypto self-tests
>>  
>> -- 
>> 2.20.1
>>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-24 14:19     ` Catalin Marinas
  -1 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:19 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, bhe, will, nsaenzjulienne, corbet,
	John.P.donnelly, bhsharma, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> function reserve_crashkernel() also used 1M alignment. So just
> replace hard-coded alignment 1M with macro CRASH_ALIGN.
[...]
> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>  	} else {
>  		unsigned long long start;
>  
> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>  						  crash_base + crash_size);
>  		if (start != crash_base) {
>  			pr_info("crashkernel reservation failed - memory is in use.\n");

There is a small functional change here for x86. Prior to this patch,
crash_base passed by the user on the command line is allowed to be 1MB
aligned. With this patch, such reservation will fail.

Is the current behaviour a bug in the current x86 code or it does allow
1MB-aligned reservations?

-- 
Catalin

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-24 14:19     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:19 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> function reserve_crashkernel() also used 1M alignment. So just
> replace hard-coded alignment 1M with macro CRASH_ALIGN.
[...]
> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>  	} else {
>  		unsigned long long start;
>  
> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>  						  crash_base + crash_size);
>  		if (start != crash_base) {
>  			pr_info("crashkernel reservation failed - memory is in use.\n");

There is a small functional change here for x86. Prior to this patch,
crash_base passed by the user on the command line is allowed to be 1MB
aligned. With this patch, such reservation will fail.

Is the current behaviour a bug in the current x86 code or it does allow
1MB-aligned reservations?

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-24 14:19     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:19 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> function reserve_crashkernel() also used 1M alignment. So just
> replace hard-coded alignment 1M with macro CRASH_ALIGN.
[...]
> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>  	} else {
>  		unsigned long long start;
>  
> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>  						  crash_base + crash_size);
>  		if (start != crash_base) {
>  			pr_info("crashkernel reservation failed - memory is in use.\n");

There is a small functional change here for x86. Prior to this patch,
crash_base passed by the user on the command line is allowed to be 1MB
aligned. With this patch, such reservation will fail.

Is the current behaviour a bug in the current x86 code or it does allow
1MB-aligned reservations?

-- 
Catalin

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-24 14:35     ` Catalin Marinas
  -1 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, bhe, will, nsaenzjulienne, corbet,
	John.P.donnelly, bhsharma, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index da769845597d..27470479e4a3 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);
>  	if (!low_base) {
>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>  		       (unsigned long)(low_size >> 20));

Is there any reason why the lower bound can't be 0 in all low cases
here? (Sorry if it's been already discussed, I lost track)

-- 
Catalin

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-24 14:35     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index da769845597d..27470479e4a3 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);
>  	if (!low_base) {
>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>  		       (unsigned long)(low_size >> 20));

Is there any reason why the lower bound can't be 0 in all low cases
here? (Sorry if it's been already discussed, I lost track)

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-24 14:35     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 14:35 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index da769845597d..27470479e4a3 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>  			return 0;
>  	}
>  
> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> +			CRASH_ADDR_LOW_MAX);
>  	if (!low_base) {
>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>  		       (unsigned long)(low_size >> 20));

Is there any reason why the lower bound can't be 0 in all low cases
here? (Sorry if it's been already discussed, I lost track)

-- 
Catalin

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
  2021-01-30  7:10   ` Chen Zhou
  (?)
@ 2021-02-24 16:04     ` Catalin Marinas
  -1 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 16:04 UTC (permalink / raw)
  To: Chen Zhou
  Cc: mingo, tglx, rppt, dyoung, bhe, will, nsaenzjulienne, corbet,
	John.P.donnelly, bhsharma, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
> 
> To solve these issues, change the behavior of crashkernel=X and
> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
> in DMA zone, and fall back to high allocation if it fails.
> We can also use "crashkernel=X,high" to select a region above DMA zone,
> which also tries to allocate at least 256M in DMA zone automatically.
> "crashkernel=Y,low" can be used to allocate specified size low memory.
> 
> Another minor change, there may be two regions reserved for crash
> dump kernel, in order to distinct from the high region and make no
> effect to the use of existing kexec-tools, rename the low region as
> "Crash kernel (low)".

I think we discussed this but I don't remember the conclusion. Is this
only renamed conditionally so that we don't break current kexec-tools?

IOW, assuming that the full crashkernel region is reserved below 4GB,
does the "(low)" suffix still appear or it's only if a high region is
additionally reserved?

> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 3f6ecae0bc68..f0caed0cb5e1 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>  static inline void crash_post_resume(void) {}
>  #endif
>  
> +#ifdef CONFIG_KEXEC_CORE
> +extern void __init reserve_crashkernel(void);
> +#endif

Why not have this in some generic header?

> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index c18aacde8bb0..69c592c546de 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>  		    kernel_data.end <= res->end)
>  			request_resource(res, &kernel_data);
>  #ifdef CONFIG_KEXEC_CORE
> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
> +		/*
> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
> +		 * region in /proc/iomem.
> +		 * In order to distinct from the high region and make no effect
> +		 * to the use of existing kexec-tools, rename the low region as
> +		 * "Crash kernel (low)".
> +		 */
> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
> +				crashk_low_res.end <= res->end) {
> +			crashk_low_res.name = "Crash kernel (low)";
> +			request_resource(res, &crashk_low_res);
> +		}
>  		if (crashk_res.end && crashk_res.start >= res->start &&
>  		    crashk_res.end <= res->end)
>  			request_resource(res, &crashk_res);

My reading of the new generic reserve_crashkernel() is that
crashk_low_res will only be populated if crask_res is above 4GB. If
that's correct, I'm fine with the renaming here since current systems
would not get a renamed low reservation (as long as they don't change
the kernel cmdline).

> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 912f64f505f7..d20f5c444ebf 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -35,6 +35,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/kasan.h>
>  #include <asm/kernel-pgtable.h>
> +#include <asm/kexec.h>
>  #include <asm/memory.h>
>  #include <asm/numa.h>
>  #include <asm/sections.h>
> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>   */
>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>  
> -#ifdef CONFIG_KEXEC_CORE
> -/*
> - * reserve_crashkernel() - reserves memory for crash kernel
> - *
> - * This function reserves memory area given in "crashkernel=" kernel command
> - * line parameter. The memory reserved is used by dump capture kernel when
> - * primary kernel is crashing.
> - */
> +#ifndef CONFIG_KEXEC_CORE
>  static void __init reserve_crashkernel(void)
>  {
[...]
>  }
> +#endif

Can we not have the dummy reserve_crashkernel() in the generic code as
well and avoid the #ifndef here?

>  #ifdef CONFIG_CRASH_DUMP
>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>  	 * reserved, so do it here.
>  	 */
>  	reserve_crashkernel();
> +#ifdef CONFIG_KEXEC_CORE
> +	/*
> +	 * The low region is intended to be used for crash dump kernel devices,
> +	 * just mark the low region as "nomap" simply.
> +	 */
> +	if (crashk_low_res.end)
> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
> +#endif

Do we do something similar for crashk_res?

Also, I can see we call crash_exclude_mem_range() only for crashk_res.
Do we need to do this for crashk_low_res as well?

-- 
Catalin

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-24 16:04     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 16:04 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
> 
> To solve these issues, change the behavior of crashkernel=X and
> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
> in DMA zone, and fall back to high allocation if it fails.
> We can also use "crashkernel=X,high" to select a region above DMA zone,
> which also tries to allocate at least 256M in DMA zone automatically.
> "crashkernel=Y,low" can be used to allocate specified size low memory.
> 
> Another minor change, there may be two regions reserved for crash
> dump kernel, in order to distinct from the high region and make no
> effect to the use of existing kexec-tools, rename the low region as
> "Crash kernel (low)".

I think we discussed this but I don't remember the conclusion. Is this
only renamed conditionally so that we don't break current kexec-tools?

IOW, assuming that the full crashkernel region is reserved below 4GB,
does the "(low)" suffix still appear or it's only if a high region is
additionally reserved?

> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 3f6ecae0bc68..f0caed0cb5e1 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>  static inline void crash_post_resume(void) {}
>  #endif
>  
> +#ifdef CONFIG_KEXEC_CORE
> +extern void __init reserve_crashkernel(void);
> +#endif

Why not have this in some generic header?

> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index c18aacde8bb0..69c592c546de 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>  		    kernel_data.end <= res->end)
>  			request_resource(res, &kernel_data);
>  #ifdef CONFIG_KEXEC_CORE
> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
> +		/*
> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
> +		 * region in /proc/iomem.
> +		 * In order to distinct from the high region and make no effect
> +		 * to the use of existing kexec-tools, rename the low region as
> +		 * "Crash kernel (low)".
> +		 */
> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
> +				crashk_low_res.end <= res->end) {
> +			crashk_low_res.name = "Crash kernel (low)";
> +			request_resource(res, &crashk_low_res);
> +		}
>  		if (crashk_res.end && crashk_res.start >= res->start &&
>  		    crashk_res.end <= res->end)
>  			request_resource(res, &crashk_res);

My reading of the new generic reserve_crashkernel() is that
crashk_low_res will only be populated if crask_res is above 4GB. If
that's correct, I'm fine with the renaming here since current systems
would not get a renamed low reservation (as long as they don't change
the kernel cmdline).

> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 912f64f505f7..d20f5c444ebf 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -35,6 +35,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/kasan.h>
>  #include <asm/kernel-pgtable.h>
> +#include <asm/kexec.h>
>  #include <asm/memory.h>
>  #include <asm/numa.h>
>  #include <asm/sections.h>
> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>   */
>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>  
> -#ifdef CONFIG_KEXEC_CORE
> -/*
> - * reserve_crashkernel() - reserves memory for crash kernel
> - *
> - * This function reserves memory area given in "crashkernel=" kernel command
> - * line parameter. The memory reserved is used by dump capture kernel when
> - * primary kernel is crashing.
> - */
> +#ifndef CONFIG_KEXEC_CORE
>  static void __init reserve_crashkernel(void)
>  {
[...]
>  }
> +#endif

Can we not have the dummy reserve_crashkernel() in the generic code as
well and avoid the #ifndef here?

>  #ifdef CONFIG_CRASH_DUMP
>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>  	 * reserved, so do it here.
>  	 */
>  	reserve_crashkernel();
> +#ifdef CONFIG_KEXEC_CORE
> +	/*
> +	 * The low region is intended to be used for crash dump kernel devices,
> +	 * just mark the low region as "nomap" simply.
> +	 */
> +	if (crashk_low_res.end)
> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
> +#endif

Do we do something similar for crashk_res?

Also, I can see we call crash_exclude_mem_range() only for crashk_res.
Do we need to do this for crashk_low_res as well?

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-24 16:04     ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-24 16:04 UTC (permalink / raw)
  To: Chen Zhou
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, bhe, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which
> will fail when there is no enough low memory.
> 2. If reserving crashkernel above 4G, in this case, crash dump
> kernel will boot failure because there is no low memory available
> for allocation.
> 
> To solve these issues, change the behavior of crashkernel=X and
> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
> in DMA zone, and fall back to high allocation if it fails.
> We can also use "crashkernel=X,high" to select a region above DMA zone,
> which also tries to allocate at least 256M in DMA zone automatically.
> "crashkernel=Y,low" can be used to allocate specified size low memory.
> 
> Another minor change, there may be two regions reserved for crash
> dump kernel, in order to distinct from the high region and make no
> effect to the use of existing kexec-tools, rename the low region as
> "Crash kernel (low)".

I think we discussed this but I don't remember the conclusion. Is this
only renamed conditionally so that we don't break current kexec-tools?

IOW, assuming that the full crashkernel region is reserved below 4GB,
does the "(low)" suffix still appear or it's only if a high region is
additionally reserved?

> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
> index 3f6ecae0bc68..f0caed0cb5e1 100644
> --- a/arch/arm64/include/asm/kexec.h
> +++ b/arch/arm64/include/asm/kexec.h
> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>  static inline void crash_post_resume(void) {}
>  #endif
>  
> +#ifdef CONFIG_KEXEC_CORE
> +extern void __init reserve_crashkernel(void);
> +#endif

Why not have this in some generic header?

> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index c18aacde8bb0..69c592c546de 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>  		    kernel_data.end <= res->end)
>  			request_resource(res, &kernel_data);
>  #ifdef CONFIG_KEXEC_CORE
> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
> +		/*
> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
> +		 * region in /proc/iomem.
> +		 * In order to distinct from the high region and make no effect
> +		 * to the use of existing kexec-tools, rename the low region as
> +		 * "Crash kernel (low)".
> +		 */
> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
> +				crashk_low_res.end <= res->end) {
> +			crashk_low_res.name = "Crash kernel (low)";
> +			request_resource(res, &crashk_low_res);
> +		}
>  		if (crashk_res.end && crashk_res.start >= res->start &&
>  		    crashk_res.end <= res->end)
>  			request_resource(res, &crashk_res);

My reading of the new generic reserve_crashkernel() is that
crashk_low_res will only be populated if crask_res is above 4GB. If
that's correct, I'm fine with the renaming here since current systems
would not get a renamed low reservation (as long as they don't change
the kernel cmdline).

> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 912f64f505f7..d20f5c444ebf 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -35,6 +35,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/kasan.h>
>  #include <asm/kernel-pgtable.h>
> +#include <asm/kexec.h>
>  #include <asm/memory.h>
>  #include <asm/numa.h>
>  #include <asm/sections.h>
> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>   */
>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>  
> -#ifdef CONFIG_KEXEC_CORE
> -/*
> - * reserve_crashkernel() - reserves memory for crash kernel
> - *
> - * This function reserves memory area given in "crashkernel=" kernel command
> - * line parameter. The memory reserved is used by dump capture kernel when
> - * primary kernel is crashing.
> - */
> +#ifndef CONFIG_KEXEC_CORE
>  static void __init reserve_crashkernel(void)
>  {
[...]
>  }
> +#endif

Can we not have the dummy reserve_crashkernel() in the generic code as
well and avoid the #ifndef here?

>  #ifdef CONFIG_CRASH_DUMP
>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>  	 * reserved, so do it here.
>  	 */
>  	reserve_crashkernel();
> +#ifdef CONFIG_KEXEC_CORE
> +	/*
> +	 * The low region is intended to be used for crash dump kernel devices,
> +	 * just mark the low region as "nomap" simply.
> +	 */
> +	if (crashk_low_res.end)
> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
> +#endif

Do we do something similar for crashk_res?

Also, I can see we call crash_exclude_mem_range() only for crashk_res.
Do we need to do this for crashk_low_res as well?

-- 
Catalin

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-02-24 14:35     ` Catalin Marinas
  (?)
@ 2021-02-25  7:08       ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:08 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Chen Zhou, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > index da769845597d..27470479e4a3 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> >  			return 0;
> >  	}
> >  
> > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > +			CRASH_ADDR_LOW_MAX);
> >  	if (!low_base) {
> >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> >  		       (unsigned long)(low_size >> 20));
> 
> Is there any reason why the lower bound can't be 0 in all low cases
> here? (Sorry if it's been already discussed, I lost track)

Seems like a good question.

This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
used to reserve memory under 4G so that kdump kernel owns memory for dma
buffer allocation. In that case, kernel usually is loaded in high
memory. In x86_64, kernel loading need be aligned to 16M because of
CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
offset for crashkernel reservation automatically"). But for crashkernel
low memory, there seems to be no reason to ask for 16M alignment, if
it's taken as dma buffer memory.

So we can make a different alignment for low memory only, e.g 2M. But
16M alignment consistent with crashkernel,high is also fine to me. The
only affect is smaller alignment can increase the possibility of
crashkernel low reservation.

Thanks
Baoquan


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25  7:08       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:08 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > index da769845597d..27470479e4a3 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> >  			return 0;
> >  	}
> >  
> > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > +			CRASH_ADDR_LOW_MAX);
> >  	if (!low_base) {
> >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> >  		       (unsigned long)(low_size >> 20));
> 
> Is there any reason why the lower bound can't be 0 in all low cases
> here? (Sorry if it's been already discussed, I lost track)

Seems like a good question.

This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
used to reserve memory under 4G so that kdump kernel owns memory for dma
buffer allocation. In that case, kernel usually is loaded in high
memory. In x86_64, kernel loading need be aligned to 16M because of
CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
offset for crashkernel reservation automatically"). But for crashkernel
low memory, there seems to be no reason to ask for 16M alignment, if
it's taken as dma buffer memory.

So we can make a different alignment for low memory only, e.g 2M. But
16M alignment consistent with crashkernel,high is also fine to me. The
only affect is smaller alignment can increase the possibility of
crashkernel low reservation.

Thanks
Baoquan


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25  7:08       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:08 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > index da769845597d..27470479e4a3 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> >  			return 0;
> >  	}
> >  
> > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > +			CRASH_ADDR_LOW_MAX);
> >  	if (!low_base) {
> >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> >  		       (unsigned long)(low_size >> 20));
> 
> Is there any reason why the lower bound can't be 0 in all low cases
> here? (Sorry if it's been already discussed, I lost track)

Seems like a good question.

This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
used to reserve memory under 4G so that kdump kernel owns memory for dma
buffer allocation. In that case, kernel usually is loaded in high
memory. In x86_64, kernel loading need be aligned to 16M because of
CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
offset for crashkernel reservation automatically"). But for crashkernel
low memory, there seems to be no reason to ask for 16M alignment, if
it's taken as dma buffer memory.

So we can make a different alignment for low memory only, e.g 2M. But
16M alignment consistent with crashkernel,high is also fine to me. The
only affect is smaller alignment can increase the possibility of
crashkernel low reservation.

Thanks
Baoquan


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-02-24 14:19     ` Catalin Marinas
  (?)
@ 2021-02-25  7:25       ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:25 UTC (permalink / raw)
  To: Catalin Marinas, ebiederm
  Cc: Chen Zhou, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> > Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> > alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> > function reserve_crashkernel() also used 1M alignment. So just
> > replace hard-coded alignment 1M with macro CRASH_ALIGN.
> [...]
> > @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >  	} else {
> >  		unsigned long long start;
> >  
> > -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> > +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >  						  crash_base + crash_size);
> >  		if (start != crash_base) {
> >  			pr_info("crashkernel reservation failed - memory is in use.\n");
> 
> There is a small functional change here for x86. Prior to this patch,
> crash_base passed by the user on the command line is allowed to be 1MB
> aligned. With this patch, such reservation will fail.
> 
> Is the current behaviour a bug in the current x86 code or it does allow
> 1MB-aligned reservations?

Hmm, you are right. Here we should keep 1MB alignment as is because
users specify the address and size, their intention should be respected.
The 1MB alignment for fixed memory region reservation was introduced in
below commit, but it doesn't tell what is Eric's request at that time, I
guess it meant respecting users' specifying.

commit 44280733e71ad15377735b42d8538c109c94d7e3
Author: Yinghai Lu <yinghai@kernel.org>
Date:   Sun Nov 22 17:18:49 2009 -0800

    x86: Change crash kernel to reserve via reserve_early()
    
    use find_e820_area()/reserve_early() instead.
    
    -v2: address Eric's request, to restore original semantics.
         will fail, if the provided address can not be used.


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-25  7:25       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:25 UTC (permalink / raw)
  To: Catalin Marinas, ebiederm
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> > Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> > alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> > function reserve_crashkernel() also used 1M alignment. So just
> > replace hard-coded alignment 1M with macro CRASH_ALIGN.
> [...]
> > @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >  	} else {
> >  		unsigned long long start;
> >  
> > -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> > +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >  						  crash_base + crash_size);
> >  		if (start != crash_base) {
> >  			pr_info("crashkernel reservation failed - memory is in use.\n");
> 
> There is a small functional change here for x86. Prior to this patch,
> crash_base passed by the user on the command line is allowed to be 1MB
> aligned. With this patch, such reservation will fail.
> 
> Is the current behaviour a bug in the current x86 code or it does allow
> 1MB-aligned reservations?

Hmm, you are right. Here we should keep 1MB alignment as is because
users specify the address and size, their intention should be respected.
The 1MB alignment for fixed memory region reservation was introduced in
below commit, but it doesn't tell what is Eric's request at that time, I
guess it meant respecting users' specifying.

commit 44280733e71ad15377735b42d8538c109c94d7e3
Author: Yinghai Lu <yinghai@kernel.org>
Date:   Sun Nov 22 17:18:49 2009 -0800

    x86: Change crash kernel to reserve via reserve_early()
    
    use find_e820_area()/reserve_early() instead.
    
    -v2: address Eric's request, to restore original semantics.
         will fail, if the provided address can not be used.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-25  7:25       ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25  7:25 UTC (permalink / raw)
  To: Catalin Marinas, ebiederm
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> > Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> > alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> > function reserve_crashkernel() also used 1M alignment. So just
> > replace hard-coded alignment 1M with macro CRASH_ALIGN.
> [...]
> > @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >  	} else {
> >  		unsigned long long start;
> >  
> > -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> > +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >  						  crash_base + crash_size);
> >  		if (start != crash_base) {
> >  			pr_info("crashkernel reservation failed - memory is in use.\n");
> 
> There is a small functional change here for x86. Prior to this patch,
> crash_base passed by the user on the command line is allowed to be 1MB
> aligned. With this patch, such reservation will fail.
> 
> Is the current behaviour a bug in the current x86 code or it does allow
> 1MB-aligned reservations?

Hmm, you are right. Here we should keep 1MB alignment as is because
users specify the address and size, their intention should be respected.
The 1MB alignment for fixed memory region reservation was introduced in
below commit, but it doesn't tell what is Eric's request at that time, I
guess it meant respecting users' specifying.

commit 44280733e71ad15377735b42d8538c109c94d7e3
Author: Yinghai Lu <yinghai@kernel.org>
Date:   Sun Nov 22 17:18:49 2009 -0800

    x86: Change crash kernel to reserve via reserve_early()
    
    use find_e820_area()/reserve_early() instead.
    
    -v2: address Eric's request, to restore original semantics.
         will fail, if the provided address can not be used.


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-02-25  7:08       ` Baoquan He
  (?)
@ 2021-02-25 14:42         ` Catalin Marinas
  -1 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-25 14:42 UTC (permalink / raw)
  To: Baoquan He
  Cc: Chen Zhou, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > index da769845597d..27470479e4a3 100644
> > > --- a/arch/x86/kernel/setup.c
> > > +++ b/arch/x86/kernel/setup.c
> > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > >  			return 0;
> > >  	}
> > >  
> > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > +			CRASH_ADDR_LOW_MAX);
> > >  	if (!low_base) {
> > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > >  		       (unsigned long)(low_size >> 20));
> > 
> > Is there any reason why the lower bound can't be 0 in all low cases
> > here? (Sorry if it's been already discussed, I lost track)
> 
> Seems like a good question.
> 
> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> used to reserve memory under 4G so that kdump kernel owns memory for dma
> buffer allocation. In that case, kernel usually is loaded in high
> memory. In x86_64, kernel loading need be aligned to 16M because of
> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> offset for crashkernel reservation automatically"). But for crashkernel
> low memory, there seems to be no reason to ask for 16M alignment, if
> it's taken as dma buffer memory.
> 
> So we can make a different alignment for low memory only, e.g 2M. But
> 16M alignment consistent with crashkernel,high is also fine to me. The
> only affect is smaller alignment can increase the possibility of
> crashkernel low reservation.

I don't mind the 16M alignment in both low and high base. But is there
any reason that the lower bound (third argument) cannot be 0 in both
reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
cases? The comment in reserve_crashkernel() only talks about the 4G
upper bound but not why we need a 16M lower bound.

-- 
Catalin

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25 14:42         ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-25 14:42 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > index da769845597d..27470479e4a3 100644
> > > --- a/arch/x86/kernel/setup.c
> > > +++ b/arch/x86/kernel/setup.c
> > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > >  			return 0;
> > >  	}
> > >  
> > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > +			CRASH_ADDR_LOW_MAX);
> > >  	if (!low_base) {
> > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > >  		       (unsigned long)(low_size >> 20));
> > 
> > Is there any reason why the lower bound can't be 0 in all low cases
> > here? (Sorry if it's been already discussed, I lost track)
> 
> Seems like a good question.
> 
> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> used to reserve memory under 4G so that kdump kernel owns memory for dma
> buffer allocation. In that case, kernel usually is loaded in high
> memory. In x86_64, kernel loading need be aligned to 16M because of
> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> offset for crashkernel reservation automatically"). But for crashkernel
> low memory, there seems to be no reason to ask for 16M alignment, if
> it's taken as dma buffer memory.
> 
> So we can make a different alignment for low memory only, e.g 2M. But
> 16M alignment consistent with crashkernel,high is also fine to me. The
> only affect is smaller alignment can increase the possibility of
> crashkernel low reservation.

I don't mind the 16M alignment in both low and high base. But is there
any reason that the lower bound (third argument) cannot be 0 in both
reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
cases? The comment in reserve_crashkernel() only talks about the 4G
upper bound but not why we need a 16M lower bound.

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25 14:42         ` Catalin Marinas
  0 siblings, 0 replies; 126+ messages in thread
From: Catalin Marinas @ 2021-02-25 14:42 UTC (permalink / raw)
  To: Baoquan He
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > index da769845597d..27470479e4a3 100644
> > > --- a/arch/x86/kernel/setup.c
> > > +++ b/arch/x86/kernel/setup.c
> > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > >  			return 0;
> > >  	}
> > >  
> > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > +			CRASH_ADDR_LOW_MAX);
> > >  	if (!low_base) {
> > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > >  		       (unsigned long)(low_size >> 20));
> > 
> > Is there any reason why the lower bound can't be 0 in all low cases
> > here? (Sorry if it's been already discussed, I lost track)
> 
> Seems like a good question.
> 
> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> used to reserve memory under 4G so that kdump kernel owns memory for dma
> buffer allocation. In that case, kernel usually is loaded in high
> memory. In x86_64, kernel loading need be aligned to 16M because of
> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> offset for crashkernel reservation automatically"). But for crashkernel
> low memory, there seems to be no reason to ask for 16M alignment, if
> it's taken as dma buffer memory.
> 
> So we can make a different alignment for low memory only, e.g 2M. But
> 16M alignment consistent with crashkernel,high is also fine to me. The
> only affect is smaller alignment can increase the possibility of
> crashkernel low reservation.

I don't mind the 16M alignment in both low and high base. But is there
any reason that the lower bound (third argument) cannot be 0 in both
reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
cases? The comment in reserve_crashkernel() only talks about the 4G
upper bound but not why we need a 16M lower bound.

-- 
Catalin

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-02-25 14:42         ` Catalin Marinas
  (?)
@ 2021-02-25 15:44           ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25 15:44 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Chen Zhou, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 02/25/21 at 02:42pm, Catalin Marinas wrote:
> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> > On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > > index da769845597d..27470479e4a3 100644
> > > > --- a/arch/x86/kernel/setup.c
> > > > +++ b/arch/x86/kernel/setup.c
> > > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > > >  			return 0;
> > > >  	}
> > > >  
> > > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > > +			CRASH_ADDR_LOW_MAX);
> > > >  	if (!low_base) {
> > > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > > >  		       (unsigned long)(low_size >> 20));
> > > 
> > > Is there any reason why the lower bound can't be 0 in all low cases
> > > here? (Sorry if it's been already discussed, I lost track)
> > 
> > Seems like a good question.
> > 
> > This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> > used to reserve memory under 4G so that kdump kernel owns memory for dma
> > buffer allocation. In that case, kernel usually is loaded in high
> > memory. In x86_64, kernel loading need be aligned to 16M because of
> > CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> > offset for crashkernel reservation automatically"). But for crashkernel
> > low memory, there seems to be no reason to ask for 16M alignment, if
> > it's taken as dma buffer memory.
> > 
> > So we can make a different alignment for low memory only, e.g 2M. But
> > 16M alignment consistent with crashkernel,high is also fine to me. The
> > only affect is smaller alignment can increase the possibility of
> > crashkernel low reservation.
> 
> I don't mind the 16M alignment in both low and high base. But is there
> any reason that the lower bound (third argument) cannot be 0 in both
> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
> cases? The comment in reserve_crashkernel() only talks about the 4G
> upper bound but not why we need a 16M lower bound.

Ah, sorry, I must have mixed this one with the alignment of fixed
memory region reservation in patch 1 when considering comments.

Hmm, in x86 we always have memory reserved in low 1M, lower bound
being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
low reservation. But for crashkernel reservation, the reason should be
kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
("x86: find offset for crashkernel reservation automatically").

So, for crashkernel low, keeping lower bound as 0 looks good to me, the
only reason is just as patch log tells. And it can skip the unnecessary
memblock searching under 16M since it will always fail, even though it
won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
and adding code comment, is also fine to me.

Thanks
Baoquan


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25 15:44           ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25 15:44 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/25/21 at 02:42pm, Catalin Marinas wrote:
> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> > On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > > index da769845597d..27470479e4a3 100644
> > > > --- a/arch/x86/kernel/setup.c
> > > > +++ b/arch/x86/kernel/setup.c
> > > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > > >  			return 0;
> > > >  	}
> > > >  
> > > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > > +			CRASH_ADDR_LOW_MAX);
> > > >  	if (!low_base) {
> > > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > > >  		       (unsigned long)(low_size >> 20));
> > > 
> > > Is there any reason why the lower bound can't be 0 in all low cases
> > > here? (Sorry if it's been already discussed, I lost track)
> > 
> > Seems like a good question.
> > 
> > This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> > used to reserve memory under 4G so that kdump kernel owns memory for dma
> > buffer allocation. In that case, kernel usually is loaded in high
> > memory. In x86_64, kernel loading need be aligned to 16M because of
> > CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> > offset for crashkernel reservation automatically"). But for crashkernel
> > low memory, there seems to be no reason to ask for 16M alignment, if
> > it's taken as dma buffer memory.
> > 
> > So we can make a different alignment for low memory only, e.g 2M. But
> > 16M alignment consistent with crashkernel,high is also fine to me. The
> > only affect is smaller alignment can increase the possibility of
> > crashkernel low reservation.
> 
> I don't mind the 16M alignment in both low and high base. But is there
> any reason that the lower bound (third argument) cannot be 0 in both
> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
> cases? The comment in reserve_crashkernel() only talks about the 4G
> upper bound but not why we need a 16M lower bound.

Ah, sorry, I must have mixed this one with the alignment of fixed
memory region reservation in patch 1 when considering comments.

Hmm, in x86 we always have memory reserved in low 1M, lower bound
being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
low reservation. But for crashkernel reservation, the reason should be
kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
("x86: find offset for crashkernel reservation automatically").

So, for crashkernel low, keeping lower bound as 0 looks good to me, the
only reason is just as patch log tells. And it can skip the unnecessary
memblock searching under 16M since it will always fail, even though it
won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
and adding code comment, is also fine to me.

Thanks
Baoquan


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-25 15:44           ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-02-25 15:44 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: wangkefeng.wang, linux-doc, Chen Zhou, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/25/21 at 02:42pm, Catalin Marinas wrote:
> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
> > On 02/24/21 at 02:35pm, Catalin Marinas wrote:
> > > On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
> > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > > > index da769845597d..27470479e4a3 100644
> > > > --- a/arch/x86/kernel/setup.c
> > > > +++ b/arch/x86/kernel/setup.c
> > > > @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
> > > >  			return 0;
> > > >  	}
> > > >  
> > > > -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
> > > > +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
> > > > +			CRASH_ADDR_LOW_MAX);
> > > >  	if (!low_base) {
> > > >  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> > > >  		       (unsigned long)(low_size >> 20));
> > > 
> > > Is there any reason why the lower bound can't be 0 in all low cases
> > > here? (Sorry if it's been already discussed, I lost track)
> > 
> > Seems like a good question.
> > 
> > This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
> > used to reserve memory under 4G so that kdump kernel owns memory for dma
> > buffer allocation. In that case, kernel usually is loaded in high
> > memory. In x86_64, kernel loading need be aligned to 16M because of
> > CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
> > offset for crashkernel reservation automatically"). But for crashkernel
> > low memory, there seems to be no reason to ask for 16M alignment, if
> > it's taken as dma buffer memory.
> > 
> > So we can make a different alignment for low memory only, e.g 2M. But
> > 16M alignment consistent with crashkernel,high is also fine to me. The
> > only affect is smaller alignment can increase the possibility of
> > crashkernel low reservation.
> 
> I don't mind the 16M alignment in both low and high base. But is there
> any reason that the lower bound (third argument) cannot be 0 in both
> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
> cases? The comment in reserve_crashkernel() only talks about the 4G
> upper bound but not why we need a 16M lower bound.

Ah, sorry, I must have mixed this one with the alignment of fixed
memory region reservation in patch 1 when considering comments.

Hmm, in x86 we always have memory reserved in low 1M, lower bound
being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
low reservation. But for crashkernel reservation, the reason should be
kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
("x86: find offset for crashkernel reservation automatically").

So, for crashkernel low, keeping lower bound as 0 looks good to me, the
only reason is just as patch log tells. And it can skip the unnecessary
memblock searching under 16M since it will always fail, even though it
won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
and adding code comment, is also fine to me.

Thanks
Baoquan


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-02-25  7:25       ` Baoquan He
  (?)
@ 2021-02-26  6:45         ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  6:45 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas, ebiederm
  Cc: mingo, tglx, rppt, dyoung, will, nsaenzjulienne, corbet,
	John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/25 15:25, Baoquan He wrote:
> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>> function reserve_crashkernel() also used 1M alignment. So just
>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>> [...]
>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>  	} else {
>>>  		unsigned long long start;
>>>  
>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>  						  crash_base + crash_size);
>>>  		if (start != crash_base) {
>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>> There is a small functional change here for x86. Prior to this patch,
>> crash_base passed by the user on the command line is allowed to be 1MB
>> aligned. With this patch, such reservation will fail.
>>
>> Is the current behaviour a bug in the current x86 code or it does allow
>> 1MB-aligned reservations?
> Hmm, you are right. Here we should keep 1MB alignment as is because
> users specify the address and size, their intention should be respected.
> The 1MB alignment for fixed memory region reservation was introduced in
> below commit, but it doesn't tell what is Eric's request at that time, I
> guess it meant respecting users' specifying.
I think we could make the alignment unified. Why is the alignment system reserved and
user specified different? Besides, there is no document about the 1MB alignment.
How about adding the alignment size(16MB) in doc  if user specified  start address as arm64 does.

Thanks,
Chen Zhou
>
> commit 44280733e71ad15377735b42d8538c109c94d7e3
> Author: Yinghai Lu <yinghai@kernel.org>
> Date:   Sun Nov 22 17:18:49 2009 -0800
>
>     x86: Change crash kernel to reserve via reserve_early()
>     
>     use find_e820_area()/reserve_early() instead.
>     
>     -v2: address Eric's request, to restore original semantics.
>          will fail, if the provided address can not be used.
>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-26  6:45         ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  6:45 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas, ebiederm
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, arnd, horms,
	corbet, dyoung, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, rppt, huawei.libin,
	prabhakar.pkin, tglx, will, kexec, nsaenzjulienne



On 2021/2/25 15:25, Baoquan He wrote:
> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>> function reserve_crashkernel() also used 1M alignment. So just
>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>> [...]
>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>  	} else {
>>>  		unsigned long long start;
>>>  
>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>  						  crash_base + crash_size);
>>>  		if (start != crash_base) {
>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>> There is a small functional change here for x86. Prior to this patch,
>> crash_base passed by the user on the command line is allowed to be 1MB
>> aligned. With this patch, such reservation will fail.
>>
>> Is the current behaviour a bug in the current x86 code or it does allow
>> 1MB-aligned reservations?
> Hmm, you are right. Here we should keep 1MB alignment as is because
> users specify the address and size, their intention should be respected.
> The 1MB alignment for fixed memory region reservation was introduced in
> below commit, but it doesn't tell what is Eric's request at that time, I
> guess it meant respecting users' specifying.
I think we could make the alignment unified. Why is the alignment system reserved and
user specified different? Besides, there is no document about the 1MB alignment.
How about adding the alignment size(16MB) in doc  if user specified  start address as arm64 does.

Thanks,
Chen Zhou
>
> commit 44280733e71ad15377735b42d8538c109c94d7e3
> Author: Yinghai Lu <yinghai@kernel.org>
> Date:   Sun Nov 22 17:18:49 2009 -0800
>
>     x86: Change crash kernel to reserve via reserve_early()
>     
>     use find_e820_area()/reserve_early() instead.
>     
>     -v2: address Eric's request, to restore original semantics.
>          will fail, if the provided address can not be used.
>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-26  6:45         ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  6:45 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas, ebiederm
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, arnd, horms,
	corbet, dyoung, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, rppt, huawei.libin,
	prabhakar.pkin, tglx, will, kexec, nsaenzjulienne



On 2021/2/25 15:25, Baoquan He wrote:
> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>> function reserve_crashkernel() also used 1M alignment. So just
>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>> [...]
>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>  	} else {
>>>  		unsigned long long start;
>>>  
>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>  						  crash_base + crash_size);
>>>  		if (start != crash_base) {
>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>> There is a small functional change here for x86. Prior to this patch,
>> crash_base passed by the user on the command line is allowed to be 1MB
>> aligned. With this patch, such reservation will fail.
>>
>> Is the current behaviour a bug in the current x86 code or it does allow
>> 1MB-aligned reservations?
> Hmm, you are right. Here we should keep 1MB alignment as is because
> users specify the address and size, their intention should be respected.
> The 1MB alignment for fixed memory region reservation was introduced in
> below commit, but it doesn't tell what is Eric's request at that time, I
> guess it meant respecting users' specifying.
I think we could make the alignment unified. Why is the alignment system reserved and
user specified different? Besides, there is no document about the 1MB alignment.
How about adding the alignment size(16MB) in doc  if user specified  start address as arm64 does.

Thanks,
Chen Zhou
>
> commit 44280733e71ad15377735b42d8538c109c94d7e3
> Author: Yinghai Lu <yinghai@kernel.org>
> Date:   Sun Nov 22 17:18:49 2009 -0800
>
>     x86: Change crash kernel to reserve via reserve_early()
>     
>     use find_e820_area()/reserve_early() instead.
>     
>     -v2: address Eric's request, to restore original semantics.
>          will fail, if the provided address can not be used.
>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
  2021-02-25 15:44           ` Baoquan He
  (?)
@ 2021-02-26  7:32             ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  7:32 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas
  Cc: mingo, tglx, rppt, dyoung, will, nsaenzjulienne, corbet,
	John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/25 23:44, Baoquan He wrote:
> On 02/25/21 at 02:42pm, Catalin Marinas wrote:
>> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
>>> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
>>>> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
>>>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>>>> index da769845597d..27470479e4a3 100644
>>>>> --- a/arch/x86/kernel/setup.c
>>>>> +++ b/arch/x86/kernel/setup.c
>>>>> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>>>>>  			return 0;
>>>>>  	}
>>>>>  
>>>>> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
>>>>> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
>>>>> +			CRASH_ADDR_LOW_MAX);
>>>>>  	if (!low_base) {
>>>>>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>>>>>  		       (unsigned long)(low_size >> 20));
>>>> Is there any reason why the lower bound can't be 0 in all low cases
>>>> here? (Sorry if it's been already discussed, I lost track)
>>> Seems like a good question.
>>>
>>> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
>>> used to reserve memory under 4G so that kdump kernel owns memory for dma
>>> buffer allocation. In that case, kernel usually is loaded in high
>>> memory. In x86_64, kernel loading need be aligned to 16M because of
>>> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
>>> offset for crashkernel reservation automatically"). But for crashkernel
>>> low memory, there seems to be no reason to ask for 16M alignment, if
>>> it's taken as dma buffer memory.
>>>
>>> So we can make a different alignment for low memory only, e.g 2M. But
>>> 16M alignment consistent with crashkernel,high is also fine to me. The
>>> only affect is smaller alignment can increase the possibility of
>>> crashkernel low reservation.
>> I don't mind the 16M alignment in both low and high base. But is there
>> any reason that the lower bound (third argument) cannot be 0 in both
>> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
>> cases? The comment in reserve_crashkernel() only talks about the 4G
>> upper bound but not why we need a 16M lower bound.
> Ah, sorry, I must have mixed this one with the alignment of fixed
> memory region reservation in patch 1 when considering comments.
>
> Hmm, in x86 we always have memory reserved in low 1M, lower bound
> being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
> low reservation. But for crashkernel reservation, the reason should be
> kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
> ("x86: find offset for crashkernel reservation automatically").
Sorry, i didn't mention in the commit message about this.

We discussed about this and the CRASH_ALIGN sounds better, so just use CRASH_ALIGN.
https://lkml.org/lkml/2020/9/4/82

Thanks,
Chen Zhou
>
> So, for crashkernel low, keeping lower bound as 0 looks good to me, the
> only reason is just as patch log tells. And it can skip the unnecessary
> memblock searching under 16M since it will always fail, even though it
> won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
> and adding code comment, is also fine to me.
>
> Thanks
> Baoquan
>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-26  7:32             ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  7:32 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, arnd, horms,
	corbet, dyoung, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, rppt, huawei.libin,
	prabhakar.pkin, tglx, will, kexec, nsaenzjulienne



On 2021/2/25 23:44, Baoquan He wrote:
> On 02/25/21 at 02:42pm, Catalin Marinas wrote:
>> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
>>> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
>>>> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
>>>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>>>> index da769845597d..27470479e4a3 100644
>>>>> --- a/arch/x86/kernel/setup.c
>>>>> +++ b/arch/x86/kernel/setup.c
>>>>> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>>>>>  			return 0;
>>>>>  	}
>>>>>  
>>>>> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
>>>>> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
>>>>> +			CRASH_ADDR_LOW_MAX);
>>>>>  	if (!low_base) {
>>>>>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>>>>>  		       (unsigned long)(low_size >> 20));
>>>> Is there any reason why the lower bound can't be 0 in all low cases
>>>> here? (Sorry if it's been already discussed, I lost track)
>>> Seems like a good question.
>>>
>>> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
>>> used to reserve memory under 4G so that kdump kernel owns memory for dma
>>> buffer allocation. In that case, kernel usually is loaded in high
>>> memory. In x86_64, kernel loading need be aligned to 16M because of
>>> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
>>> offset for crashkernel reservation automatically"). But for crashkernel
>>> low memory, there seems to be no reason to ask for 16M alignment, if
>>> it's taken as dma buffer memory.
>>>
>>> So we can make a different alignment for low memory only, e.g 2M. But
>>> 16M alignment consistent with crashkernel,high is also fine to me. The
>>> only affect is smaller alignment can increase the possibility of
>>> crashkernel low reservation.
>> I don't mind the 16M alignment in both low and high base. But is there
>> any reason that the lower bound (third argument) cannot be 0 in both
>> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
>> cases? The comment in reserve_crashkernel() only talks about the 4G
>> upper bound but not why we need a 16M lower bound.
> Ah, sorry, I must have mixed this one with the alignment of fixed
> memory region reservation in patch 1 when considering comments.
>
> Hmm, in x86 we always have memory reserved in low 1M, lower bound
> being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
> low reservation. But for crashkernel reservation, the reason should be
> kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
> ("x86: find offset for crashkernel reservation automatically").
Sorry, i didn't mention in the commit message about this.

We discussed about this and the CRASH_ALIGN sounds better, so just use CRASH_ALIGN.
https://lkml.org/lkml/2020/9/4/82

Thanks,
Chen Zhou
>
> So, for crashkernel low, keeping lower bound as 0 looks good to me, the
> only reason is just as patch log tells. And it can skip the unnecessary
> memblock searching under 16M since it will always fail, even though it
> won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
> and adding code comment, is also fine to me.
>
> Thanks
> Baoquan
>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent
@ 2021-02-26  7:32             ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26  7:32 UTC (permalink / raw)
  To: Baoquan He, Catalin Marinas
  Cc: linux-arm-kernel, John.P.donnelly, wangkefeng.wang, arnd, horms,
	corbet, dyoung, xiexiuqi, guohanjun, linux-kernel, robh+dt,
	linux-doc, mingo, james.morse, rppt, huawei.libin,
	prabhakar.pkin, tglx, will, kexec, nsaenzjulienne



On 2021/2/25 23:44, Baoquan He wrote:
> On 02/25/21 at 02:42pm, Catalin Marinas wrote:
>> On Thu, Feb 25, 2021 at 03:08:46PM +0800, Baoquan He wrote:
>>> On 02/24/21 at 02:35pm, Catalin Marinas wrote:
>>>> On Sat, Jan 30, 2021 at 03:10:16PM +0800, Chen Zhou wrote:
>>>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>>>> index da769845597d..27470479e4a3 100644
>>>>> --- a/arch/x86/kernel/setup.c
>>>>> +++ b/arch/x86/kernel/setup.c
>>>>> @@ -439,7 +439,8 @@ static int __init reserve_crashkernel_low(void)
>>>>>  			return 0;
>>>>>  	}
>>>>>  
>>>>> -	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
>>>>> +	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, CRASH_ALIGN,
>>>>> +			CRASH_ADDR_LOW_MAX);
>>>>>  	if (!low_base) {
>>>>>  		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
>>>>>  		       (unsigned long)(low_size >> 20));
>>>> Is there any reason why the lower bound can't be 0 in all low cases
>>>> here? (Sorry if it's been already discussed, I lost track)
>>> Seems like a good question.
>>>
>>> This reserve_crashkernel_low(), paired with reserve_crashkernel_high(), is
>>> used to reserve memory under 4G so that kdump kernel owns memory for dma
>>> buffer allocation. In that case, kernel usually is loaded in high
>>> memory. In x86_64, kernel loading need be aligned to 16M because of
>>> CONFIG_PHYSICAL_START, please see commit 32105f7fd8faa7b ("x86: find
>>> offset for crashkernel reservation automatically"). But for crashkernel
>>> low memory, there seems to be no reason to ask for 16M alignment, if
>>> it's taken as dma buffer memory.
>>>
>>> So we can make a different alignment for low memory only, e.g 2M. But
>>> 16M alignment consistent with crashkernel,high is also fine to me. The
>>> only affect is smaller alignment can increase the possibility of
>>> crashkernel low reservation.
>> I don't mind the 16M alignment in both low and high base. But is there
>> any reason that the lower bound (third argument) cannot be 0 in both
>> reserve_crashkernel() (the low attempt) and reserve_crashkernel_low()
>> cases? The comment in reserve_crashkernel() only talks about the 4G
>> upper bound but not why we need a 16M lower bound.
> Ah, sorry, I must have mixed this one with the alignment of fixed
> memory region reservation in patch 1 when considering comments.
>
> Hmm, in x86 we always have memory reserved in low 1M, lower bound
> being 0 or 16M (kernel alignment) doesn't make difference on crashkernel
> low reservation. But for crashkernel reservation, the reason should be
> kernel loading alignment being 16M, please see commit 32105f7fd8faa7b
> ("x86: find offset for crashkernel reservation automatically").
Sorry, i didn't mention in the commit message about this.

We discussed about this and the CRASH_ALIGN sounds better, so just use CRASH_ALIGN.
https://lkml.org/lkml/2020/9/4/82

Thanks,
Chen Zhou
>
> So, for crashkernel low, keeping lower bound as 0 looks good to me, the
> only reason is just as patch log tells. And it can skip the unnecessary
> memblock searching under 16M since it will always fail, even though it
> won't matter much. Or changing it to CRASH_ALIGN as this patch is doing,
> and adding code comment, is also fine to me.
>
> Thanks
> Baoquan
>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
  2021-02-24 16:04     ` Catalin Marinas
  (?)
@ 2021-02-26 10:31       ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:31 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: mingo, tglx, rppt, dyoung, will, nsaenzjulienne, corbet,
	John.P.donnelly, bhsharma, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/25 0:04, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>> will fail when there is no enough low memory.
>> 2. If reserving crashkernel above 4G, in this case, crash dump
>> kernel will boot failure because there is no low memory available
>> for allocation.
>>
>> To solve these issues, change the behavior of crashkernel=X and
>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>> in DMA zone, and fall back to high allocation if it fails.
>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>> which also tries to allocate at least 256M in DMA zone automatically.
>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>
>> Another minor change, there may be two regions reserved for crash
>> dump kernel, in order to distinct from the high region and make no
>> effect to the use of existing kexec-tools, rename the low region as
>> "Crash kernel (low)".
> I think we discussed this but I don't remember the conclusion. Is this
> only renamed conditionally so that we don't break current kexec-tools?
Yes.
>
> IOW, assuming that the full crashkernel region is reserved below 4GB,
> does the "(low)" suffix still appear or it's only if a high region is
> additionally reserved?
Suffix "low" only appear if a high region is additionally reserved.
>
>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>> --- a/arch/arm64/include/asm/kexec.h
>> +++ b/arch/arm64/include/asm/kexec.h
>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>  static inline void crash_post_resume(void) {}
>>  #endif
>>  
>> +#ifdef CONFIG_KEXEC_CORE
>> +extern void __init reserve_crashkernel(void);
>> +#endif
> Why not have this in some generic header?
>
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index c18aacde8bb0..69c592c546de 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>  		    kernel_data.end <= res->end)
>>  			request_resource(res, &kernel_data);
>>  #ifdef CONFIG_KEXEC_CORE
>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>> +		/*
>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>> +		 * region in /proc/iomem.
>> +		 * In order to distinct from the high region and make no effect
>> +		 * to the use of existing kexec-tools, rename the low region as
>> +		 * "Crash kernel (low)".
>> +		 */
>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>> +				crashk_low_res.end <= res->end) {
>> +			crashk_low_res.name = "Crash kernel (low)";
>> +			request_resource(res, &crashk_low_res);
>> +		}
>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>  		    crashk_res.end <= res->end)
>>  			request_resource(res, &crashk_res);
> My reading of the new generic reserve_crashkernel() is that
> crashk_low_res will only be populated if crask_res is above 4GB. If
> that's correct, I'm fine with the renaming here since current systems
> would not get a renamed low reservation (as long as they don't change
> the kernel cmdline).
>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 912f64f505f7..d20f5c444ebf 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -35,6 +35,7 @@
>>  #include <asm/fixmap.h>
>>  #include <asm/kasan.h>
>>  #include <asm/kernel-pgtable.h>
>> +#include <asm/kexec.h>
>>  #include <asm/memory.h>
>>  #include <asm/numa.h>
>>  #include <asm/sections.h>
>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>   */
>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -/*
>> - * reserve_crashkernel() - reserves memory for crash kernel
>> - *
>> - * This function reserves memory area given in "crashkernel=" kernel command
>> - * line parameter. The memory reserved is used by dump capture kernel when
>> - * primary kernel is crashing.
>> - */
>> +#ifndef CONFIG_KEXEC_CORE
>>  static void __init reserve_crashkernel(void)
>>  {
> [...]
>>  }
>> +#endif
> Can we not have the dummy reserve_crashkernel() in the generic code as
> well and avoid the #ifndef here?
You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
 
Baoquan also mentioned about this.
Now all the arch that support kdump have the dummy reserve_crashkernel() and
function declaration, such as arm/arm64/ppc/s390..

But currently different arch may have different CONFIG and different function declaration about this,
for example,

for s390,
static void __init reserve_crashkernel(void)
{                  
#ifdef CONFIG_CRASH_DUMP
...
#endif        
}

for ppc,
#ifdef CONFIG_KEXEC_CORE
extern void reserve_crashkernel(void);
#else
static inline void reserve_crashkernel(void) { ; }
#endif

If we move these to generic header we need think about:
1. the related config in different arch
2. function declaration(static/non static)

As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?

>
>>  #ifdef CONFIG_CRASH_DUMP
>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>  	 * reserved, so do it here.
>>  	 */
>>  	reserve_crashkernel();
>> +#ifdef CONFIG_KEXEC_CORE
>> +	/*
>> +	 * The low region is intended to be used for crash dump kernel devices,
>> +	 * just mark the low region as "nomap" simply.
>> +	 */
>> +	if (crashk_low_res.end)
>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>> +#endif
> Do we do something similar for crashk_res?
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
elf core header, initrd...

Different with this, the crashk_low_res is only for crash dump kernel devices.
>
> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
> Do we need to do this for crashk_low_res as well?
You are right, i missed about this. Will do in next version.

Thanks,
Chen Zhou
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-26 10:31       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:31 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, nsaenzjulienne, prabhakar.pkin, rppt



On 2021/2/25 0:04, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>> will fail when there is no enough low memory.
>> 2. If reserving crashkernel above 4G, in this case, crash dump
>> kernel will boot failure because there is no low memory available
>> for allocation.
>>
>> To solve these issues, change the behavior of crashkernel=X and
>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>> in DMA zone, and fall back to high allocation if it fails.
>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>> which also tries to allocate at least 256M in DMA zone automatically.
>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>
>> Another minor change, there may be two regions reserved for crash
>> dump kernel, in order to distinct from the high region and make no
>> effect to the use of existing kexec-tools, rename the low region as
>> "Crash kernel (low)".
> I think we discussed this but I don't remember the conclusion. Is this
> only renamed conditionally so that we don't break current kexec-tools?
Yes.
>
> IOW, assuming that the full crashkernel region is reserved below 4GB,
> does the "(low)" suffix still appear or it's only if a high region is
> additionally reserved?
Suffix "low" only appear if a high region is additionally reserved.
>
>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>> --- a/arch/arm64/include/asm/kexec.h
>> +++ b/arch/arm64/include/asm/kexec.h
>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>  static inline void crash_post_resume(void) {}
>>  #endif
>>  
>> +#ifdef CONFIG_KEXEC_CORE
>> +extern void __init reserve_crashkernel(void);
>> +#endif
> Why not have this in some generic header?
>
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index c18aacde8bb0..69c592c546de 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>  		    kernel_data.end <= res->end)
>>  			request_resource(res, &kernel_data);
>>  #ifdef CONFIG_KEXEC_CORE
>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>> +		/*
>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>> +		 * region in /proc/iomem.
>> +		 * In order to distinct from the high region and make no effect
>> +		 * to the use of existing kexec-tools, rename the low region as
>> +		 * "Crash kernel (low)".
>> +		 */
>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>> +				crashk_low_res.end <= res->end) {
>> +			crashk_low_res.name = "Crash kernel (low)";
>> +			request_resource(res, &crashk_low_res);
>> +		}
>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>  		    crashk_res.end <= res->end)
>>  			request_resource(res, &crashk_res);
> My reading of the new generic reserve_crashkernel() is that
> crashk_low_res will only be populated if crask_res is above 4GB. If
> that's correct, I'm fine with the renaming here since current systems
> would not get a renamed low reservation (as long as they don't change
> the kernel cmdline).
>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 912f64f505f7..d20f5c444ebf 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -35,6 +35,7 @@
>>  #include <asm/fixmap.h>
>>  #include <asm/kasan.h>
>>  #include <asm/kernel-pgtable.h>
>> +#include <asm/kexec.h>
>>  #include <asm/memory.h>
>>  #include <asm/numa.h>
>>  #include <asm/sections.h>
>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>   */
>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -/*
>> - * reserve_crashkernel() - reserves memory for crash kernel
>> - *
>> - * This function reserves memory area given in "crashkernel=" kernel command
>> - * line parameter. The memory reserved is used by dump capture kernel when
>> - * primary kernel is crashing.
>> - */
>> +#ifndef CONFIG_KEXEC_CORE
>>  static void __init reserve_crashkernel(void)
>>  {
> [...]
>>  }
>> +#endif
> Can we not have the dummy reserve_crashkernel() in the generic code as
> well and avoid the #ifndef here?
You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
 
Baoquan also mentioned about this.
Now all the arch that support kdump have the dummy reserve_crashkernel() and
function declaration, such as arm/arm64/ppc/s390..

But currently different arch may have different CONFIG and different function declaration about this,
for example,

for s390,
static void __init reserve_crashkernel(void)
{                  
#ifdef CONFIG_CRASH_DUMP
...
#endif        
}

for ppc,
#ifdef CONFIG_KEXEC_CORE
extern void reserve_crashkernel(void);
#else
static inline void reserve_crashkernel(void) { ; }
#endif

If we move these to generic header we need think about:
1. the related config in different arch
2. function declaration(static/non static)

As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?

>
>>  #ifdef CONFIG_CRASH_DUMP
>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>  	 * reserved, so do it here.
>>  	 */
>>  	reserve_crashkernel();
>> +#ifdef CONFIG_KEXEC_CORE
>> +	/*
>> +	 * The low region is intended to be used for crash dump kernel devices,
>> +	 * just mark the low region as "nomap" simply.
>> +	 */
>> +	if (crashk_low_res.end)
>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>> +#endif
> Do we do something similar for crashk_res?
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
elf core header, initrd...

Different with this, the crashk_low_res is only for crash dump kernel devices.
>
> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
> Do we need to do this for crashk_low_res as well?
You are right, i missed about this. Will do in next version.

Thanks,
Chen Zhou
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-26 10:31       ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:31 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, nsaenzjulienne, prabhakar.pkin, rppt



On 2021/2/25 0:04, Catalin Marinas wrote:
> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>> will fail when there is no enough low memory.
>> 2. If reserving crashkernel above 4G, in this case, crash dump
>> kernel will boot failure because there is no low memory available
>> for allocation.
>>
>> To solve these issues, change the behavior of crashkernel=X and
>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>> in DMA zone, and fall back to high allocation if it fails.
>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>> which also tries to allocate at least 256M in DMA zone automatically.
>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>
>> Another minor change, there may be two regions reserved for crash
>> dump kernel, in order to distinct from the high region and make no
>> effect to the use of existing kexec-tools, rename the low region as
>> "Crash kernel (low)".
> I think we discussed this but I don't remember the conclusion. Is this
> only renamed conditionally so that we don't break current kexec-tools?
Yes.
>
> IOW, assuming that the full crashkernel region is reserved below 4GB,
> does the "(low)" suffix still appear or it's only if a high region is
> additionally reserved?
Suffix "low" only appear if a high region is additionally reserved.
>
>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>> --- a/arch/arm64/include/asm/kexec.h
>> +++ b/arch/arm64/include/asm/kexec.h
>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>  static inline void crash_post_resume(void) {}
>>  #endif
>>  
>> +#ifdef CONFIG_KEXEC_CORE
>> +extern void __init reserve_crashkernel(void);
>> +#endif
> Why not have this in some generic header?
>
>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>> index c18aacde8bb0..69c592c546de 100644
>> --- a/arch/arm64/kernel/setup.c
>> +++ b/arch/arm64/kernel/setup.c
>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>  		    kernel_data.end <= res->end)
>>  			request_resource(res, &kernel_data);
>>  #ifdef CONFIG_KEXEC_CORE
>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>> +		/*
>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>> +		 * region in /proc/iomem.
>> +		 * In order to distinct from the high region and make no effect
>> +		 * to the use of existing kexec-tools, rename the low region as
>> +		 * "Crash kernel (low)".
>> +		 */
>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>> +				crashk_low_res.end <= res->end) {
>> +			crashk_low_res.name = "Crash kernel (low)";
>> +			request_resource(res, &crashk_low_res);
>> +		}
>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>  		    crashk_res.end <= res->end)
>>  			request_resource(res, &crashk_res);
> My reading of the new generic reserve_crashkernel() is that
> crashk_low_res will only be populated if crask_res is above 4GB. If
> that's correct, I'm fine with the renaming here since current systems
> would not get a renamed low reservation (as long as they don't change
> the kernel cmdline).
>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 912f64f505f7..d20f5c444ebf 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -35,6 +35,7 @@
>>  #include <asm/fixmap.h>
>>  #include <asm/kasan.h>
>>  #include <asm/kernel-pgtable.h>
>> +#include <asm/kexec.h>
>>  #include <asm/memory.h>
>>  #include <asm/numa.h>
>>  #include <asm/sections.h>
>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>   */
>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>  
>> -#ifdef CONFIG_KEXEC_CORE
>> -/*
>> - * reserve_crashkernel() - reserves memory for crash kernel
>> - *
>> - * This function reserves memory area given in "crashkernel=" kernel command
>> - * line parameter. The memory reserved is used by dump capture kernel when
>> - * primary kernel is crashing.
>> - */
>> +#ifndef CONFIG_KEXEC_CORE
>>  static void __init reserve_crashkernel(void)
>>  {
> [...]
>>  }
>> +#endif
> Can we not have the dummy reserve_crashkernel() in the generic code as
> well and avoid the #ifndef here?
You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
 
Baoquan also mentioned about this.
Now all the arch that support kdump have the dummy reserve_crashkernel() and
function declaration, such as arm/arm64/ppc/s390..

But currently different arch may have different CONFIG and different function declaration about this,
for example,

for s390,
static void __init reserve_crashkernel(void)
{                  
#ifdef CONFIG_CRASH_DUMP
...
#endif        
}

for ppc,
#ifdef CONFIG_KEXEC_CORE
extern void reserve_crashkernel(void);
#else
static inline void reserve_crashkernel(void) { ; }
#endif

If we move these to generic header we need think about:
1. the related config in different arch
2. function declaration(static/non static)

As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?

>
>>  #ifdef CONFIG_CRASH_DUMP
>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>  	 * reserved, so do it here.
>>  	 */
>>  	reserve_crashkernel();
>> +#ifdef CONFIG_KEXEC_CORE
>> +	/*
>> +	 * The low region is intended to be used for crash dump kernel devices,
>> +	 * just mark the low region as "nomap" simply.
>> +	 */
>> +	if (crashk_low_res.end)
>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>> +#endif
> Do we do something similar for crashk_res?
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
elf core header, initrd...

Different with this, the crashk_low_res is only for crash dump kernel devices.
>
> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
> Do we need to do this for crashk_low_res as well?
You are right, i missed about this. Will do in next version.

Thanks,
Chen Zhou
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
  2021-02-26 10:31       ` chenzhou
  (?)
@ 2021-02-26 10:43         ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:43 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: mingo, tglx, rppt, dyoung, will, nsaenzjulienne, corbet,
	John.P.donnelly, bhsharma, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/2/26 18:31, chenzhou wrote:
>
> On 2021/2/25 0:04, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>>> There are following issues in arm64 kdump:
>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>>> will fail when there is no enough low memory.
>>> 2. If reserving crashkernel above 4G, in this case, crash dump
>>> kernel will boot failure because there is no low memory available
>>> for allocation.
>>>
>>> To solve these issues, change the behavior of crashkernel=X and
>>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>>> in DMA zone, and fall back to high allocation if it fails.
>>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>>> which also tries to allocate at least 256M in DMA zone automatically.
>>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>>
>>> Another minor change, there may be two regions reserved for crash
>>> dump kernel, in order to distinct from the high region and make no
>>> effect to the use of existing kexec-tools, rename the low region as
>>> "Crash kernel (low)".
>> I think we discussed this but I don't remember the conclusion. Is this
>> only renamed conditionally so that we don't break current kexec-tools?
> Yes.
>> IOW, assuming that the full crashkernel region is reserved below 4GB,
>> does the "(low)" suffix still appear or it's only if a high region is
>> additionally reserved?
> Suffix "low" only appear if a high region is additionally reserved.
>>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>>> --- a/arch/arm64/include/asm/kexec.h
>>> +++ b/arch/arm64/include/asm/kexec.h
>>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>>  static inline void crash_post_resume(void) {}
>>>  #endif
>>>  
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +extern void __init reserve_crashkernel(void);
>>> +#endif
>> Why not have this in some generic header?
>>
>>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>>> index c18aacde8bb0..69c592c546de 100644
>>> --- a/arch/arm64/kernel/setup.c
>>> +++ b/arch/arm64/kernel/setup.c
>>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>>  		    kernel_data.end <= res->end)
>>>  			request_resource(res, &kernel_data);
>>>  #ifdef CONFIG_KEXEC_CORE
>>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>>> +		/*
>>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>>> +		 * region in /proc/iomem.
>>> +		 * In order to distinct from the high region and make no effect
>>> +		 * to the use of existing kexec-tools, rename the low region as
>>> +		 * "Crash kernel (low)".
>>> +		 */
>>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>>> +				crashk_low_res.end <= res->end) {
>>> +			crashk_low_res.name = "Crash kernel (low)";
>>> +			request_resource(res, &crashk_low_res);
>>> +		}
>>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>>  		    crashk_res.end <= res->end)
>>>  			request_resource(res, &crashk_res);
>> My reading of the new generic reserve_crashkernel() is that
>> crashk_low_res will only be populated if crask_res is above 4GB. If
>> that's correct, I'm fine with the renaming here since current systems
>> would not get a renamed low reservation (as long as they don't change
>> the kernel cmdline).
>>
>>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>>> index 912f64f505f7..d20f5c444ebf 100644
>>> --- a/arch/arm64/mm/init.c
>>> +++ b/arch/arm64/mm/init.c
>>> @@ -35,6 +35,7 @@
>>>  #include <asm/fixmap.h>
>>>  #include <asm/kasan.h>
>>>  #include <asm/kernel-pgtable.h>
>>> +#include <asm/kexec.h>
>>>  #include <asm/memory.h>
>>>  #include <asm/numa.h>
>>>  #include <asm/sections.h>
>>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>>   */
>>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>>  
>>> -#ifdef CONFIG_KEXEC_CORE
>>> -/*
>>> - * reserve_crashkernel() - reserves memory for crash kernel
>>> - *
>>> - * This function reserves memory area given in "crashkernel=" kernel command
>>> - * line parameter. The memory reserved is used by dump capture kernel when
>>> - * primary kernel is crashing.
>>> - */
>>> +#ifndef CONFIG_KEXEC_CORE
>>>  static void __init reserve_crashkernel(void)
>>>  {
>> [...]
>>>  }
>>> +#endif
>> Can we not have the dummy reserve_crashkernel() in the generic code as
>> well and avoid the #ifndef here?
> You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
>  
> Baoquan also mentioned about this.
> Now all the arch that support kdump have the dummy reserve_crashkernel() and
> function declaration, such as arm/arm64/ppc/s390..
>
> But currently different arch may have different CONFIG and different function declaration about this,
> for example,
>
> for s390,
> static void __init reserve_crashkernel(void)
> {                  
> #ifdef CONFIG_CRASH_DUMP
> ...
> #endif        
> }
>
> for ppc,
> #ifdef CONFIG_KEXEC_CORE
> extern void reserve_crashkernel(void);
> #else
> static inline void reserve_crashkernel(void) { ; }
> #endif
>
> If we move these to generic header we need think about:
> 1. the related config in different arch
> 2. function declaration(static/non static)
>
> As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?
>
>>>  #ifdef CONFIG_CRASH_DUMP
>>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>>  	 * reserved, so do it here.
>>>  	 */
>>>  	reserve_crashkernel();
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +	/*
>>> +	 * The low region is intended to be used for crash dump kernel devices,
>>> +	 * just mark the low region as "nomap" simply.
>>> +	 */
>>> +	if (crashk_low_res.end)
>>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>>> +#endif
>> Do we do something similar for crashk_res?
> Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
> elf core header, initrd...

Sorry, missed one comma after crash kernel.
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel,
elf core header, initrd and so on.


>
> Different with this, the crashk_low_res is only for crash dump kernel devices.
>> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
>> Do we need to do this for crashk_low_res as well?
> You are right, i missed about this. Will do in next version.
>
> Thanks,
> Chen Zhou


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-26 10:43         ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:43 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, nsaenzjulienne, prabhakar.pkin, rppt



On 2021/2/26 18:31, chenzhou wrote:
>
> On 2021/2/25 0:04, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>>> There are following issues in arm64 kdump:
>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>>> will fail when there is no enough low memory.
>>> 2. If reserving crashkernel above 4G, in this case, crash dump
>>> kernel will boot failure because there is no low memory available
>>> for allocation.
>>>
>>> To solve these issues, change the behavior of crashkernel=X and
>>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>>> in DMA zone, and fall back to high allocation if it fails.
>>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>>> which also tries to allocate at least 256M in DMA zone automatically.
>>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>>
>>> Another minor change, there may be two regions reserved for crash
>>> dump kernel, in order to distinct from the high region and make no
>>> effect to the use of existing kexec-tools, rename the low region as
>>> "Crash kernel (low)".
>> I think we discussed this but I don't remember the conclusion. Is this
>> only renamed conditionally so that we don't break current kexec-tools?
> Yes.
>> IOW, assuming that the full crashkernel region is reserved below 4GB,
>> does the "(low)" suffix still appear or it's only if a high region is
>> additionally reserved?
> Suffix "low" only appear if a high region is additionally reserved.
>>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>>> --- a/arch/arm64/include/asm/kexec.h
>>> +++ b/arch/arm64/include/asm/kexec.h
>>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>>  static inline void crash_post_resume(void) {}
>>>  #endif
>>>  
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +extern void __init reserve_crashkernel(void);
>>> +#endif
>> Why not have this in some generic header?
>>
>>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>>> index c18aacde8bb0..69c592c546de 100644
>>> --- a/arch/arm64/kernel/setup.c
>>> +++ b/arch/arm64/kernel/setup.c
>>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>>  		    kernel_data.end <= res->end)
>>>  			request_resource(res, &kernel_data);
>>>  #ifdef CONFIG_KEXEC_CORE
>>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>>> +		/*
>>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>>> +		 * region in /proc/iomem.
>>> +		 * In order to distinct from the high region and make no effect
>>> +		 * to the use of existing kexec-tools, rename the low region as
>>> +		 * "Crash kernel (low)".
>>> +		 */
>>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>>> +				crashk_low_res.end <= res->end) {
>>> +			crashk_low_res.name = "Crash kernel (low)";
>>> +			request_resource(res, &crashk_low_res);
>>> +		}
>>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>>  		    crashk_res.end <= res->end)
>>>  			request_resource(res, &crashk_res);
>> My reading of the new generic reserve_crashkernel() is that
>> crashk_low_res will only be populated if crask_res is above 4GB. If
>> that's correct, I'm fine with the renaming here since current systems
>> would not get a renamed low reservation (as long as they don't change
>> the kernel cmdline).
>>
>>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>>> index 912f64f505f7..d20f5c444ebf 100644
>>> --- a/arch/arm64/mm/init.c
>>> +++ b/arch/arm64/mm/init.c
>>> @@ -35,6 +35,7 @@
>>>  #include <asm/fixmap.h>
>>>  #include <asm/kasan.h>
>>>  #include <asm/kernel-pgtable.h>
>>> +#include <asm/kexec.h>
>>>  #include <asm/memory.h>
>>>  #include <asm/numa.h>
>>>  #include <asm/sections.h>
>>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>>   */
>>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>>  
>>> -#ifdef CONFIG_KEXEC_CORE
>>> -/*
>>> - * reserve_crashkernel() - reserves memory for crash kernel
>>> - *
>>> - * This function reserves memory area given in "crashkernel=" kernel command
>>> - * line parameter. The memory reserved is used by dump capture kernel when
>>> - * primary kernel is crashing.
>>> - */
>>> +#ifndef CONFIG_KEXEC_CORE
>>>  static void __init reserve_crashkernel(void)
>>>  {
>> [...]
>>>  }
>>> +#endif
>> Can we not have the dummy reserve_crashkernel() in the generic code as
>> well and avoid the #ifndef here?
> You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
>  
> Baoquan also mentioned about this.
> Now all the arch that support kdump have the dummy reserve_crashkernel() and
> function declaration, such as arm/arm64/ppc/s390..
>
> But currently different arch may have different CONFIG and different function declaration about this,
> for example,
>
> for s390,
> static void __init reserve_crashkernel(void)
> {                  
> #ifdef CONFIG_CRASH_DUMP
> ...
> #endif        
> }
>
> for ppc,
> #ifdef CONFIG_KEXEC_CORE
> extern void reserve_crashkernel(void);
> #else
> static inline void reserve_crashkernel(void) { ; }
> #endif
>
> If we move these to generic header we need think about:
> 1. the related config in different arch
> 2. function declaration(static/non static)
>
> As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?
>
>>>  #ifdef CONFIG_CRASH_DUMP
>>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>>  	 * reserved, so do it here.
>>>  	 */
>>>  	reserve_crashkernel();
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +	/*
>>> +	 * The low region is intended to be used for crash dump kernel devices,
>>> +	 * just mark the low region as "nomap" simply.
>>> +	 */
>>> +	if (crashk_low_res.end)
>>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>>> +#endif
>> Do we do something similar for crashk_res?
> Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
> elf core header, initrd...

Sorry, missed one comma after crash kernel.
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel,
elf core header, initrd and so on.


>
> Different with this, the crashk_low_res is only for crash dump kernel devices.
>> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
>> Do we need to do this for crashk_low_res as well?
> You are right, i missed about this. Will do in next version.
>
> Thanks,
> Chen Zhou


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X
@ 2021-02-26 10:43         ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-02-26 10:43 UTC (permalink / raw)
  To: Catalin Marinas, bhe
  Cc: wangkefeng.wang, linux-doc, bhsharma, huawei.libin, guohanjun,
	will, corbet, mingo, dyoung, John.P.donnelly, arnd, xiexiuqi,
	horms, tglx, linux-arm-kernel, kexec, linux-kernel, robh+dt,
	james.morse, nsaenzjulienne, prabhakar.pkin, rppt



On 2021/2/26 18:31, chenzhou wrote:
>
> On 2021/2/25 0:04, Catalin Marinas wrote:
>> On Sat, Jan 30, 2021 at 03:10:22PM +0800, Chen Zhou wrote:
>>> There are following issues in arm64 kdump:
>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which
>>> will fail when there is no enough low memory.
>>> 2. If reserving crashkernel above 4G, in this case, crash dump
>>> kernel will boot failure because there is no low memory available
>>> for allocation.
>>>
>>> To solve these issues, change the behavior of crashkernel=X and
>>> introduce crashkernel=X,[high,low]. crashkernel=X tries low allocation
>>> in DMA zone, and fall back to high allocation if it fails.
>>> We can also use "crashkernel=X,high" to select a region above DMA zone,
>>> which also tries to allocate at least 256M in DMA zone automatically.
>>> "crashkernel=Y,low" can be used to allocate specified size low memory.
>>>
>>> Another minor change, there may be two regions reserved for crash
>>> dump kernel, in order to distinct from the high region and make no
>>> effect to the use of existing kexec-tools, rename the low region as
>>> "Crash kernel (low)".
>> I think we discussed this but I don't remember the conclusion. Is this
>> only renamed conditionally so that we don't break current kexec-tools?
> Yes.
>> IOW, assuming that the full crashkernel region is reserved below 4GB,
>> does the "(low)" suffix still appear or it's only if a high region is
>> additionally reserved?
> Suffix "low" only appear if a high region is additionally reserved.
>>> diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
>>> index 3f6ecae0bc68..f0caed0cb5e1 100644
>>> --- a/arch/arm64/include/asm/kexec.h
>>> +++ b/arch/arm64/include/asm/kexec.h
>>> @@ -96,6 +96,10 @@ static inline void crash_prepare_suspend(void) {}
>>>  static inline void crash_post_resume(void) {}
>>>  #endif
>>>  
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +extern void __init reserve_crashkernel(void);
>>> +#endif
>> Why not have this in some generic header?
>>
>>> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
>>> index c18aacde8bb0..69c592c546de 100644
>>> --- a/arch/arm64/kernel/setup.c
>>> +++ b/arch/arm64/kernel/setup.c
>>> @@ -238,7 +238,18 @@ static void __init request_standard_resources(void)
>>>  		    kernel_data.end <= res->end)
>>>  			request_resource(res, &kernel_data);
>>>  #ifdef CONFIG_KEXEC_CORE
>>> -		/* Userspace will find "Crash kernel" region in /proc/iomem. */
>>> +		/*
>>> +		 * Userspace will find "Crash kernel" or "Crash kernel (low)"
>>> +		 * region in /proc/iomem.
>>> +		 * In order to distinct from the high region and make no effect
>>> +		 * to the use of existing kexec-tools, rename the low region as
>>> +		 * "Crash kernel (low)".
>>> +		 */
>>> +		if (crashk_low_res.end && crashk_low_res.start >= res->start &&
>>> +				crashk_low_res.end <= res->end) {
>>> +			crashk_low_res.name = "Crash kernel (low)";
>>> +			request_resource(res, &crashk_low_res);
>>> +		}
>>>  		if (crashk_res.end && crashk_res.start >= res->start &&
>>>  		    crashk_res.end <= res->end)
>>>  			request_resource(res, &crashk_res);
>> My reading of the new generic reserve_crashkernel() is that
>> crashk_low_res will only be populated if crask_res is above 4GB. If
>> that's correct, I'm fine with the renaming here since current systems
>> would not get a renamed low reservation (as long as they don't change
>> the kernel cmdline).
>>
>>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>>> index 912f64f505f7..d20f5c444ebf 100644
>>> --- a/arch/arm64/mm/init.c
>>> +++ b/arch/arm64/mm/init.c
>>> @@ -35,6 +35,7 @@
>>>  #include <asm/fixmap.h>
>>>  #include <asm/kasan.h>
>>>  #include <asm/kernel-pgtable.h>
>>> +#include <asm/kexec.h>
>>>  #include <asm/memory.h>
>>>  #include <asm/numa.h>
>>>  #include <asm/sections.h>
>>> @@ -61,66 +62,11 @@ EXPORT_SYMBOL(memstart_addr);
>>>   */
>>>  phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>>  
>>> -#ifdef CONFIG_KEXEC_CORE
>>> -/*
>>> - * reserve_crashkernel() - reserves memory for crash kernel
>>> - *
>>> - * This function reserves memory area given in "crashkernel=" kernel command
>>> - * line parameter. The memory reserved is used by dump capture kernel when
>>> - * primary kernel is crashing.
>>> - */
>>> +#ifndef CONFIG_KEXEC_CORE
>>>  static void __init reserve_crashkernel(void)
>>>  {
>> [...]
>>>  }
>>> +#endif
>> Can we not have the dummy reserve_crashkernel() in the generic code as
>> well and avoid the #ifndef here?
> You mean put the dummy reserve_crashkernel() and the relate function declaration in some generic header?
>  
> Baoquan also mentioned about this.
> Now all the arch that support kdump have the dummy reserve_crashkernel() and
> function declaration, such as arm/arm64/ppc/s390..
>
> But currently different arch may have different CONFIG and different function declaration about this,
> for example,
>
> for s390,
> static void __init reserve_crashkernel(void)
> {                  
> #ifdef CONFIG_CRASH_DUMP
> ...
> #endif        
> }
>
> for ppc,
> #ifdef CONFIG_KEXEC_CORE
> extern void reserve_crashkernel(void);
> #else
> static inline void reserve_crashkernel(void) { ; }
> #endif
>
> If we move these to generic header we need think about:
> 1. the related config in different arch
> 2. function declaration(static/non static)
>
> As Baoquan said in patch 9, how about leave with it for now and i try to solve this later?
>
>>>  #ifdef CONFIG_CRASH_DUMP
>>>  static int __init early_init_dt_scan_elfcorehdr(unsigned long node,
>>> @@ -446,6 +392,14 @@ void __init bootmem_init(void)
>>>  	 * reserved, so do it here.
>>>  	 */
>>>  	reserve_crashkernel();
>>> +#ifdef CONFIG_KEXEC_CORE
>>> +	/*
>>> +	 * The low region is intended to be used for crash dump kernel devices,
>>> +	 * just mark the low region as "nomap" simply.
>>> +	 */
>>> +	if (crashk_low_res.end)
>>> +		memblock_mark_nomap(crashk_low_res.start, resource_size(&crashk_low_res));
>>> +#endif
>> Do we do something similar for crashk_res?
> Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel
> elf core header, initrd...

Sorry, missed one comma after crash kernel.
Not. In the primary kernel(production kernel), we need to use crashk_res memory for crash kernel,
elf core header, initrd and so on.


>
> Different with this, the crashk_low_res is only for crash dump kernel devices.
>> Also, I can see we call crash_exclude_mem_range() only for crashk_res.
>> Do we need to do this for crashk_low_res as well?
> You are right, i missed about this. Will do in next version.
>
> Thanks,
> Chen Zhou


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-02-26  6:45         ` chenzhou
  (?)
@ 2021-02-26 15:38           ` Eric W. Biederman
  -1 siblings, 0 replies; 126+ messages in thread
From: Eric W. Biederman @ 2021-02-26 15:38 UTC (permalink / raw)
  To: chenzhou
  Cc: Baoquan He, Catalin Marinas, mingo, tglx, rppt, dyoung, will,
	nsaenzjulienne, corbet, John.P.donnelly, prabhakar.pkin, horms,
	robh+dt, arnd, james.morse, xiexiuqi, guohanjun, huawei.libin,
	wangkefeng.wang, linux-doc, linux-arm-kernel, linux-kernel,
	kexec

chenzhou <chenzhou10@huawei.com> writes:

> On 2021/2/25 15:25, Baoquan He wrote:
>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>> [...]
>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>  	} else {
>>>>  		unsigned long long start;
>>>>  
>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>  						  crash_base + crash_size);
>>>>  		if (start != crash_base) {
>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>> There is a small functional change here for x86. Prior to this patch,
>>> crash_base passed by the user on the command line is allowed to be 1MB
>>> aligned. With this patch, such reservation will fail.
>>>
>>> Is the current behaviour a bug in the current x86 code or it does allow
>>> 1MB-aligned reservations?
>> Hmm, you are right. Here we should keep 1MB alignment as is because
>> users specify the address and size, their intention should be respected.
>> The 1MB alignment for fixed memory region reservation was introduced in
>> below commit, but it doesn't tell what is Eric's request at that time, I
>> guess it meant respecting users' specifying.


> I think we could make the alignment unified. Why is the alignment system reserved and
> user specified different? Besides, there is no document about the 1MB alignment.
> How about adding the alignment size(16MB) in doc  if user specified
> start address as arm64 does.

Looking at what the code is doing.  Attempting to reserve a crash region
at the location the user specified.  Adding unnecessary alignment
constraints is totally broken. 

I am not even certain enforcing a 1MB alignment makes sense.  I suspect
it was added so that we don't accidentally reserve low memory on x86.
Frankly I am not even certain that makes sense.

Now in practice there might be an argument for 2MB alignment that goes
with huge page sizes on x86.  But until someone finds that there are
actual problems with 1MB alignment I would not touch it.

The proper response to something that isn't documented and confusing is
not to arbitrarily change it and risk breaking users.  Especially in
this case where it is clear that adding additional alignment is total
nonsense.  The proper response to something that isn't clear and
documented is to dig in and document it, or to leave it alone and let it
be the next persons problem.

In this case there is no reason for changing this bit of code.
All CRASH_ALIGN is about is a default alignment when none is specified.
It is not a functional requirement but just something so that things
come out nicely.


Eric

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-26 15:38           ` Eric W. Biederman
  0 siblings, 0 replies; 126+ messages in thread
From: Eric W. Biederman @ 2021-02-26 15:38 UTC (permalink / raw)
  To: chenzhou
  Cc: wangkefeng.wang, linux-doc, Catalin Marinas, huawei.libin,
	guohanjun, will, Baoquan He, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne

chenzhou <chenzhou10@huawei.com> writes:

> On 2021/2/25 15:25, Baoquan He wrote:
>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>> [...]
>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>  	} else {
>>>>  		unsigned long long start;
>>>>  
>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>  						  crash_base + crash_size);
>>>>  		if (start != crash_base) {
>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>> There is a small functional change here for x86. Prior to this patch,
>>> crash_base passed by the user on the command line is allowed to be 1MB
>>> aligned. With this patch, such reservation will fail.
>>>
>>> Is the current behaviour a bug in the current x86 code or it does allow
>>> 1MB-aligned reservations?
>> Hmm, you are right. Here we should keep 1MB alignment as is because
>> users specify the address and size, their intention should be respected.
>> The 1MB alignment for fixed memory region reservation was introduced in
>> below commit, but it doesn't tell what is Eric's request at that time, I
>> guess it meant respecting users' specifying.


> I think we could make the alignment unified. Why is the alignment system reserved and
> user specified different? Besides, there is no document about the 1MB alignment.
> How about adding the alignment size(16MB) in doc  if user specified
> start address as arm64 does.

Looking at what the code is doing.  Attempting to reserve a crash region
at the location the user specified.  Adding unnecessary alignment
constraints is totally broken. 

I am not even certain enforcing a 1MB alignment makes sense.  I suspect
it was added so that we don't accidentally reserve low memory on x86.
Frankly I am not even certain that makes sense.

Now in practice there might be an argument for 2MB alignment that goes
with huge page sizes on x86.  But until someone finds that there are
actual problems with 1MB alignment I would not touch it.

The proper response to something that isn't documented and confusing is
not to arbitrarily change it and risk breaking users.  Especially in
this case where it is clear that adding additional alignment is total
nonsense.  The proper response to something that isn't clear and
documented is to dig in and document it, or to leave it alone and let it
be the next persons problem.

In this case there is no reason for changing this bit of code.
All CRASH_ALIGN is about is a default alignment when none is specified.
It is not a functional requirement but just something so that things
come out nicely.


Eric

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-02-26 15:38           ` Eric W. Biederman
  0 siblings, 0 replies; 126+ messages in thread
From: Eric W. Biederman @ 2021-02-26 15:38 UTC (permalink / raw)
  To: chenzhou
  Cc: wangkefeng.wang, linux-doc, Catalin Marinas, huawei.libin,
	guohanjun, will, Baoquan He, corbet, mingo, dyoung,
	John.P.donnelly, arnd, xiexiuqi, horms, tglx, linux-arm-kernel,
	kexec, linux-kernel, robh+dt, james.morse, rppt, prabhakar.pkin,
	nsaenzjulienne

chenzhou <chenzhou10@huawei.com> writes:

> On 2021/2/25 15:25, Baoquan He wrote:
>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>> [...]
>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>  	} else {
>>>>  		unsigned long long start;
>>>>  
>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>  						  crash_base + crash_size);
>>>>  		if (start != crash_base) {
>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>> There is a small functional change here for x86. Prior to this patch,
>>> crash_base passed by the user on the command line is allowed to be 1MB
>>> aligned. With this patch, such reservation will fail.
>>>
>>> Is the current behaviour a bug in the current x86 code or it does allow
>>> 1MB-aligned reservations?
>> Hmm, you are right. Here we should keep 1MB alignment as is because
>> users specify the address and size, their intention should be respected.
>> The 1MB alignment for fixed memory region reservation was introduced in
>> below commit, but it doesn't tell what is Eric's request at that time, I
>> guess it meant respecting users' specifying.


> I think we could make the alignment unified. Why is the alignment system reserved and
> user specified different? Besides, there is no document about the 1MB alignment.
> How about adding the alignment size(16MB) in doc  if user specified
> start address as arm64 does.

Looking at what the code is doing.  Attempting to reserve a crash region
at the location the user specified.  Adding unnecessary alignment
constraints is totally broken. 

I am not even certain enforcing a 1MB alignment makes sense.  I suspect
it was added so that we don't accidentally reserve low memory on x86.
Frankly I am not even certain that makes sense.

Now in practice there might be an argument for 2MB alignment that goes
with huge page sizes on x86.  But until someone finds that there are
actual problems with 1MB alignment I would not touch it.

The proper response to something that isn't documented and confusing is
not to arbitrarily change it and risk breaking users.  Especially in
this case where it is clear that adding additional alignment is total
nonsense.  The proper response to something that isn't clear and
documented is to dig in and document it, or to leave it alone and let it
be the next persons problem.

In this case there is no reason for changing this bit of code.
All CRASH_ALIGN is about is a default alignment when none is specified.
It is not a functional requirement but just something so that things
come out nicely.


Eric

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-02-26 15:38           ` Eric W. Biederman
  (?)
@ 2021-03-02  7:43             ` Baoquan He
  -1 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-03-02  7:43 UTC (permalink / raw)
  To: Eric W. Biederman, chenzhou
  Cc: Catalin Marinas, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec

On 02/26/21 at 09:38am, Eric W. Biederman wrote:
> chenzhou <chenzhou10@huawei.com> writes:
> 
> > On 2021/2/25 15:25, Baoquan He wrote:
> >> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> >>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> >>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> >>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> >>>> function reserve_crashkernel() also used 1M alignment. So just
> >>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
> >>> [...]
> >>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >>>>  	} else {
> >>>>  		unsigned long long start;
> >>>>  
> >>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> >>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >>>>  						  crash_base + crash_size);
> >>>>  		if (start != crash_base) {
> >>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
> >>> There is a small functional change here for x86. Prior to this patch,
> >>> crash_base passed by the user on the command line is allowed to be 1MB
> >>> aligned. With this patch, such reservation will fail.
> >>>
> >>> Is the current behaviour a bug in the current x86 code or it does allow
> >>> 1MB-aligned reservations?
> >> Hmm, you are right. Here we should keep 1MB alignment as is because
> >> users specify the address and size, their intention should be respected.
> >> The 1MB alignment for fixed memory region reservation was introduced in
> >> below commit, but it doesn't tell what is Eric's request at that time, I
> >> guess it meant respecting users' specifying.
> 
> 
> > I think we could make the alignment unified. Why is the alignment system reserved and
> > user specified different? Besides, there is no document about the 1MB alignment.
> > How about adding the alignment size(16MB) in doc  if user specified
> > start address as arm64 does.
> 
> Looking at what the code is doing.  Attempting to reserve a crash region
> at the location the user specified.  Adding unnecessary alignment
> constraints is totally broken. 
> 
> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
> it was added so that we don't accidentally reserve low memory on x86.
> Frankly I am not even certain that makes sense.
> 
> Now in practice there might be an argument for 2MB alignment that goes
> with huge page sizes on x86.  But until someone finds that there are
> actual problems with 1MB alignment I would not touch it.
> 
> The proper response to something that isn't documented and confusing is
> not to arbitrarily change it and risk breaking users.  Especially in
> this case where it is clear that adding additional alignment is total
> nonsense.  The proper response to something that isn't clear and
> documented is to dig in and document it, or to leave it alone and let it

Sounds reasonable. Then adding document or code comment around looks
like a good way to go further so that people can easily get why its
alignment is different than other reservation.

> be the next persons problem.
> 
> In this case there is no reason for changing this bit of code.
> All CRASH_ALIGN is about is a default alignment when none is specified.
> It is not a functional requirement but just something so that things
> come out nicely.
> 
> 
> Eric
> 


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-03-02  7:43             ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-03-02  7:43 UTC (permalink / raw)
  To: Eric W. Biederman, chenzhou
  Cc: wangkefeng.wang, linux-doc, Catalin Marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/26/21 at 09:38am, Eric W. Biederman wrote:
> chenzhou <chenzhou10@huawei.com> writes:
> 
> > On 2021/2/25 15:25, Baoquan He wrote:
> >> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> >>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> >>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> >>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> >>>> function reserve_crashkernel() also used 1M alignment. So just
> >>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
> >>> [...]
> >>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >>>>  	} else {
> >>>>  		unsigned long long start;
> >>>>  
> >>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> >>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >>>>  						  crash_base + crash_size);
> >>>>  		if (start != crash_base) {
> >>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
> >>> There is a small functional change here for x86. Prior to this patch,
> >>> crash_base passed by the user on the command line is allowed to be 1MB
> >>> aligned. With this patch, such reservation will fail.
> >>>
> >>> Is the current behaviour a bug in the current x86 code or it does allow
> >>> 1MB-aligned reservations?
> >> Hmm, you are right. Here we should keep 1MB alignment as is because
> >> users specify the address and size, their intention should be respected.
> >> The 1MB alignment for fixed memory region reservation was introduced in
> >> below commit, but it doesn't tell what is Eric's request at that time, I
> >> guess it meant respecting users' specifying.
> 
> 
> > I think we could make the alignment unified. Why is the alignment system reserved and
> > user specified different? Besides, there is no document about the 1MB alignment.
> > How about adding the alignment size(16MB) in doc  if user specified
> > start address as arm64 does.
> 
> Looking at what the code is doing.  Attempting to reserve a crash region
> at the location the user specified.  Adding unnecessary alignment
> constraints is totally broken. 
> 
> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
> it was added so that we don't accidentally reserve low memory on x86.
> Frankly I am not even certain that makes sense.
> 
> Now in practice there might be an argument for 2MB alignment that goes
> with huge page sizes on x86.  But until someone finds that there are
> actual problems with 1MB alignment I would not touch it.
> 
> The proper response to something that isn't documented and confusing is
> not to arbitrarily change it and risk breaking users.  Especially in
> this case where it is clear that adding additional alignment is total
> nonsense.  The proper response to something that isn't clear and
> documented is to dig in and document it, or to leave it alone and let it

Sounds reasonable. Then adding document or code comment around looks
like a good way to go further so that people can easily get why its
alignment is different than other reservation.

> be the next persons problem.
> 
> In this case there is no reason for changing this bit of code.
> All CRASH_ALIGN is about is a default alignment when none is specified.
> It is not a functional requirement but just something so that things
> come out nicely.
> 
> 
> Eric
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-03-02  7:43             ` Baoquan He
  0 siblings, 0 replies; 126+ messages in thread
From: Baoquan He @ 2021-03-02  7:43 UTC (permalink / raw)
  To: Eric W. Biederman, chenzhou
  Cc: wangkefeng.wang, linux-doc, Catalin Marinas, huawei.libin,
	guohanjun, will, corbet, mingo, dyoung, John.P.donnelly, arnd,
	xiexiuqi, horms, tglx, linux-arm-kernel, kexec, linux-kernel,
	robh+dt, james.morse, rppt, prabhakar.pkin, nsaenzjulienne

On 02/26/21 at 09:38am, Eric W. Biederman wrote:
> chenzhou <chenzhou10@huawei.com> writes:
> 
> > On 2021/2/25 15:25, Baoquan He wrote:
> >> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
> >>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
> >>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
> >>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
> >>>> function reserve_crashkernel() also used 1M alignment. So just
> >>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
> >>> [...]
> >>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
> >>>>  	} else {
> >>>>  		unsigned long long start;
> >>>>  
> >>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
> >>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
> >>>>  						  crash_base + crash_size);
> >>>>  		if (start != crash_base) {
> >>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
> >>> There is a small functional change here for x86. Prior to this patch,
> >>> crash_base passed by the user on the command line is allowed to be 1MB
> >>> aligned. With this patch, such reservation will fail.
> >>>
> >>> Is the current behaviour a bug in the current x86 code or it does allow
> >>> 1MB-aligned reservations?
> >> Hmm, you are right. Here we should keep 1MB alignment as is because
> >> users specify the address and size, their intention should be respected.
> >> The 1MB alignment for fixed memory region reservation was introduced in
> >> below commit, but it doesn't tell what is Eric's request at that time, I
> >> guess it meant respecting users' specifying.
> 
> 
> > I think we could make the alignment unified. Why is the alignment system reserved and
> > user specified different? Besides, there is no document about the 1MB alignment.
> > How about adding the alignment size(16MB) in doc  if user specified
> > start address as arm64 does.
> 
> Looking at what the code is doing.  Attempting to reserve a crash region
> at the location the user specified.  Adding unnecessary alignment
> constraints is totally broken. 
> 
> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
> it was added so that we don't accidentally reserve low memory on x86.
> Frankly I am not even certain that makes sense.
> 
> Now in practice there might be an argument for 2MB alignment that goes
> with huge page sizes on x86.  But until someone finds that there are
> actual problems with 1MB alignment I would not touch it.
> 
> The proper response to something that isn't documented and confusing is
> not to arbitrarily change it and risk breaking users.  Especially in
> this case where it is clear that adding additional alignment is total
> nonsense.  The proper response to something that isn't clear and
> documented is to dig in and document it, or to leave it alone and let it

Sounds reasonable. Then adding document or code comment around looks
like a good way to go further so that people can easily get why its
alignment is different than other reservation.

> be the next persons problem.
> 
> In this case there is no reason for changing this bit of code.
> All CRASH_ALIGN is about is a default alignment when none is specified.
> It is not a functional requirement but just something so that things
> come out nicely.
> 
> 
> Eric
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
  2021-03-02  7:43             ` Baoquan He
  (?)
@ 2021-03-29  2:34               ` chenzhou
  -1 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-03-29  2:34 UTC (permalink / raw)
  To: Baoquan He, Eric W. Biederman
  Cc: Catalin Marinas, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/3/2 15:43, Baoquan He wrote:
> On 02/26/21 at 09:38am, Eric W. Biederman wrote:
>> chenzhou <chenzhou10@huawei.com> writes:
>>
>>> On 2021/2/25 15:25, Baoquan He wrote:
>>>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>>>> [...]
>>>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>>>  	} else {
>>>>>>  		unsigned long long start;
>>>>>>  
>>>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>>>  						  crash_base + crash_size);
>>>>>>  		if (start != crash_base) {
>>>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>>>> There is a small functional change here for x86. Prior to this patch,
>>>>> crash_base passed by the user on the command line is allowed to be 1MB
>>>>> aligned. With this patch, such reservation will fail.
>>>>>
>>>>> Is the current behaviour a bug in the current x86 code or it does allow
>>>>> 1MB-aligned reservations?
>>>> Hmm, you are right. Here we should keep 1MB alignment as is because
>>>> users specify the address and size, their intention should be respected.
>>>> The 1MB alignment for fixed memory region reservation was introduced in
>>>> below commit, but it doesn't tell what is Eric's request at that time, I
>>>> guess it meant respecting users' specifying.
>>
>>> I think we could make the alignment unified. Why is the alignment system reserved and
>>> user specified different? Besides, there is no document about the 1MB alignment.
>>> How about adding the alignment size(16MB) in doc  if user specified
>>> start address as arm64 does.
>> Looking at what the code is doing.  Attempting to reserve a crash region
>> at the location the user specified.  Adding unnecessary alignment
>> constraints is totally broken. 
>>
>> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
>> it was added so that we don't accidentally reserve low memory on x86.
>> Frankly I am not even certain that makes sense.
>>
>> Now in practice there might be an argument for 2MB alignment that goes
>> with huge page sizes on x86.  But until someone finds that there are
>> actual problems with 1MB alignment I would not touch it.
>>
>> The proper response to something that isn't documented and confusing is
>> not to arbitrarily change it and risk breaking users.  Especially in
>> this case where it is clear that adding additional alignment is total
>> nonsense.  The proper response to something that isn't clear and
>> documented is to dig in and document it, or to leave it alone and let it
> Sounds reasonable. Then adding document or code comment around looks
> like a good way to go further so that people can easily get why its
> alignment is different than other reservation.
Hi Baoquan & Eric,

Sorry for late reply, i missed it earlier.

Thanks for your explanation, i will just leave the 1MB alignment here as is.

I will introduce CRASH_ALIGN_SPECIFIED to help make function reserve_crashkernel generic.
CRASH_ALIGN_SPECIFIED is used for user specified start address which is distinct from
default CRASH_ALIGN.

Thanks,
Chen Zhou
>
>> be the next persons problem.
>>
>> In this case there is no reason for changing this bit of code.
>> All CRASH_ALIGN is about is a default alignment when none is specified.
>> It is not a functional requirement but just something so that things
>> come out nicely.
>>
>>
>> Eric
>>
> .
>


^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-03-29  2:34               ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-03-29  2:34 UTC (permalink / raw)
  To: Baoquan He, Eric W. Biederman
  Cc: Catalin Marinas, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/3/2 15:43, Baoquan He wrote:
> On 02/26/21 at 09:38am, Eric W. Biederman wrote:
>> chenzhou <chenzhou10@huawei.com> writes:
>>
>>> On 2021/2/25 15:25, Baoquan He wrote:
>>>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>>>> [...]
>>>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>>>  	} else {
>>>>>>  		unsigned long long start;
>>>>>>  
>>>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>>>  						  crash_base + crash_size);
>>>>>>  		if (start != crash_base) {
>>>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>>>> There is a small functional change here for x86. Prior to this patch,
>>>>> crash_base passed by the user on the command line is allowed to be 1MB
>>>>> aligned. With this patch, such reservation will fail.
>>>>>
>>>>> Is the current behaviour a bug in the current x86 code or it does allow
>>>>> 1MB-aligned reservations?
>>>> Hmm, you are right. Here we should keep 1MB alignment as is because
>>>> users specify the address and size, their intention should be respected.
>>>> The 1MB alignment for fixed memory region reservation was introduced in
>>>> below commit, but it doesn't tell what is Eric's request at that time, I
>>>> guess it meant respecting users' specifying.
>>
>>> I think we could make the alignment unified. Why is the alignment system reserved and
>>> user specified different? Besides, there is no document about the 1MB alignment.
>>> How about adding the alignment size(16MB) in doc  if user specified
>>> start address as arm64 does.
>> Looking at what the code is doing.  Attempting to reserve a crash region
>> at the location the user specified.  Adding unnecessary alignment
>> constraints is totally broken. 
>>
>> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
>> it was added so that we don't accidentally reserve low memory on x86.
>> Frankly I am not even certain that makes sense.
>>
>> Now in practice there might be an argument for 2MB alignment that goes
>> with huge page sizes on x86.  But until someone finds that there are
>> actual problems with 1MB alignment I would not touch it.
>>
>> The proper response to something that isn't documented and confusing is
>> not to arbitrarily change it and risk breaking users.  Especially in
>> this case where it is clear that adding additional alignment is total
>> nonsense.  The proper response to something that isn't clear and
>> documented is to dig in and document it, or to leave it alone and let it
> Sounds reasonable. Then adding document or code comment around looks
> like a good way to go further so that people can easily get why its
> alignment is different than other reservation.
Hi Baoquan & Eric,

Sorry for late reply, i missed it earlier.

Thanks for your explanation, i will just leave the 1MB alignment here as is.

I will introduce CRASH_ALIGN_SPECIFIED to help make function reserve_crashkernel generic.
CRASH_ALIGN_SPECIFIED is used for user specified start address which is distinct from
default CRASH_ALIGN.

Thanks,
Chen Zhou
>
>> be the next persons problem.
>>
>> In this case there is no reason for changing this bit of code.
>> All CRASH_ALIGN is about is a default alignment when none is specified.
>> It is not a functional requirement but just something so that things
>> come out nicely.
>>
>>
>> Eric
>>
> .
>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 126+ messages in thread
* Re: [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN
@ 2021-03-29  2:34               ` chenzhou
  0 siblings, 0 replies; 126+ messages in thread
From: chenzhou @ 2021-03-29  2:34 UTC (permalink / raw)
  To: Baoquan He, Eric W. Biederman
  Cc: Catalin Marinas, mingo, tglx, rppt, dyoung, will, nsaenzjulienne,
	corbet, John.P.donnelly, prabhakar.pkin, horms, robh+dt, arnd,
	james.morse, xiexiuqi, guohanjun, huawei.libin, wangkefeng.wang,
	linux-doc, linux-arm-kernel, linux-kernel, kexec



On 2021/3/2 15:43, Baoquan He wrote:
> On 02/26/21 at 09:38am, Eric W. Biederman wrote:
>> chenzhou <chenzhou10@huawei.com> writes:
>>
>>> On 2021/2/25 15:25, Baoquan He wrote:
>>>> On 02/24/21 at 02:19pm, Catalin Marinas wrote:
>>>>> On Sat, Jan 30, 2021 at 03:10:15PM +0800, Chen Zhou wrote:
>>>>>> Move CRASH_ALIGN to header asm/kexec.h for later use. Besides, the
>>>>>> alignment of crash kernel regions in x86 is 16M(CRASH_ALIGN), but
>>>>>> function reserve_crashkernel() also used 1M alignment. So just
>>>>>> replace hard-coded alignment 1M with macro CRASH_ALIGN.
>>>>> [...]
>>>>>> @@ -510,7 +507,7 @@ static void __init reserve_crashkernel(void)
>>>>>>  	} else {
>>>>>>  		unsigned long long start;
>>>>>>  
>>>>>> -		start = memblock_phys_alloc_range(crash_size, SZ_1M, crash_base,
>>>>>> +		start = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base,
>>>>>>  						  crash_base + crash_size);
>>>>>>  		if (start != crash_base) {
>>>>>>  			pr_info("crashkernel reservation failed - memory is in use.\n");
>>>>> There is a small functional change here for x86. Prior to this patch,
>>>>> crash_base passed by the user on the command line is allowed to be 1MB
>>>>> aligned. With this patch, such reservation will fail.
>>>>>
>>>>> Is the current behaviour a bug in the current x86 code or it does allow
>>>>> 1MB-aligned reservations?
>>>> Hmm, you are right. Here we should keep 1MB alignment as is because
>>>> users specify the address and size, their intention should be respected.
>>>> The 1MB alignment for fixed memory region reservation was introduced in
>>>> below commit, but it doesn't tell what is Eric's request at that time, I
>>>> guess it meant respecting users' specifying.
>>
>>> I think we could make the alignment unified. Why is the alignment system reserved and
>>> user specified different? Besides, there is no document about the 1MB alignment.
>>> How about adding the alignment size(16MB) in doc  if user specified
>>> start address as arm64 does.
>> Looking at what the code is doing.  Attempting to reserve a crash region
>> at the location the user specified.  Adding unnecessary alignment
>> constraints is totally broken. 
>>
>> I am not even certain enforcing a 1MB alignment makes sense.  I suspect
>> it was added so that we don't accidentally reserve low memory on x86.
>> Frankly I am not even certain that makes sense.
>>
>> Now in practice there might be an argument for 2MB alignment that goes
>> with huge page sizes on x86.  But until someone finds that there are
>> actual problems with 1MB alignment I would not touch it.
>>
>> The proper response to something that isn't documented and confusing is
>> not to arbitrarily change it and risk breaking users.  Especially in
>> this case where it is clear that adding additional alignment is total
>> nonsense.  The proper response to something that isn't clear and
>> documented is to dig in and document it, or to leave it alone and let it
> Sounds reasonable. Then adding document or code comment around looks
> like a good way to go further so that people can easily get why its
> alignment is different than other reservation.
Hi Baoquan & Eric,

Sorry for late reply, i missed it earlier.

Thanks for your explanation, i will just leave the 1MB alignment here as is.

I will introduce CRASH_ALIGN_SPECIFIED to help make function reserve_crashkernel generic.
CRASH_ALIGN_SPECIFIED is used for user specified start address which is distinct from
default CRASH_ALIGN.

Thanks,
Chen Zhou
>
>> be the next persons problem.
>>
>> In this case there is no reason for changing this bit of code.
>> All CRASH_ALIGN is about is a default alignment when none is specified.
>> It is not a functional requirement but just something so that things
>> come out nicely.
>>
>>
>> Eric
>>
> .
>


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

^ permalink raw reply	[flat|nested] 126+ messages in thread
end of thread, other threads:[~2021-03-29 21:33 UTC | newest]

Thread overview: 126+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-30  7:10 [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump Chen Zhou
2021-01-30  7:10 ` Chen Zhou
2021-01-30  7:10 ` Chen Zhou
2021-01-30  7:10 ` [PATCH v14 01/11] x86: kdump: replace the hard-coded alignment with macro CRASH_ALIGN Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  3:29   ` Baoquan He
2021-02-18  3:29     ` Baoquan He
2021-02-24 14:19   ` Catalin Marinas
2021-02-24 14:19     ` Catalin Marinas
2021-02-24 14:19     ` Catalin Marinas
2021-02-25  7:25     ` Baoquan He
2021-02-25  7:25       ` Baoquan He
2021-02-25  7:25       ` Baoquan He
2021-02-26  6:45       ` chenzhou
2021-02-26  6:45         ` chenzhou
2021-02-26  6:45         ` chenzhou
2021-02-26 15:38         ` Eric W. Biederman
2021-02-26 15:38           ` Eric W. Biederman
2021-02-26 15:38           ` Eric W. Biederman
2021-03-02  7:43           ` Baoquan He
2021-03-02  7:43             ` Baoquan He
2021-03-02  7:43             ` Baoquan He
2021-03-29  2:34             ` chenzhou
2021-03-29  2:34               ` chenzhou
2021-03-29  2:34               ` chenzhou
2021-01-30  7:10 ` [PATCH v14 02/11] x86: kdump: make the lower bound of crash kernel reservation consistent Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  3:33   ` Baoquan He
2021-02-18  3:33     ` Baoquan He
2021-02-24 14:35   ` Catalin Marinas
2021-02-24 14:35     ` Catalin Marinas
2021-02-24 14:35     ` Catalin Marinas
2021-02-25  7:08     ` Baoquan He
2021-02-25  7:08       ` Baoquan He
2021-02-25  7:08       ` Baoquan He
2021-02-25 14:42       ` Catalin Marinas
2021-02-25 14:42         ` Catalin Marinas
2021-02-25 14:42         ` Catalin Marinas
2021-02-25 15:44         ` Baoquan He
2021-02-25 15:44           ` Baoquan He
2021-02-25 15:44           ` Baoquan He
2021-02-26  7:32           ` chenzhou
2021-02-26  7:32             ` chenzhou
2021-02-26  7:32             ` chenzhou
2021-01-30  7:10 ` [PATCH v14 03/11] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel() Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  8:23   ` Baoquan He
2021-02-18  8:23     ` Baoquan He
2021-02-18  8:23     ` Baoquan He
2021-01-30  7:10 ` [PATCH v14 04/11] x86: kdump: move xen_pv_domain() check and insert_resource() to setup_arch() Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  4:14   ` Baoquan He
2021-02-18  4:14     ` Baoquan He
2021-01-30  7:10 ` [PATCH v14 05/11] x86: kdump: move reserve_crashkernel[_low]() into crash_core.c Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10 ` [PATCH v14 06/11] x86/elf: Move vmcore_elf_check_arch_cross to arch/x86/include/asm/elf.h Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  6:31   ` Baoquan He
2021-02-18  6:31     ` Baoquan He
2021-02-18  6:31     ` Baoquan He
2021-02-18  7:05     ` chenzhou
2021-02-18  7:05       ` chenzhou
2021-02-18  7:05       ` chenzhou
2021-01-30  7:10 ` [PATCH v14 07/11] arm64: kdump: introduce some macroes for crash kernel reservation Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-04 16:20   ` Nicolas Saenz Julienne
2021-02-04 16:20     ` Nicolas Saenz Julienne
2021-02-04 16:20     ` Nicolas Saenz Julienne
2021-02-04 16:27     ` Nicolas Saenz Julienne
2021-02-04 16:27       ` Nicolas Saenz Julienne
2021-02-04 16:27       ` Nicolas Saenz Julienne
2021-01-30  7:10 ` [PATCH v14 08/11] arm64: kdump: reimplement crashkernel=X Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-24 16:04   ` Catalin Marinas
2021-02-24 16:04     ` Catalin Marinas
2021-02-24 16:04     ` Catalin Marinas
2021-02-26 10:31     ` chenzhou
2021-02-26 10:31       ` chenzhou
2021-02-26 10:31       ` chenzhou
2021-02-26 10:43       ` chenzhou
2021-02-26 10:43         ` chenzhou
2021-02-26 10:43         ` chenzhou
2021-01-30  7:10 ` [PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-02-18  7:31   ` Baoquan He
2021-02-18  7:31     ` Baoquan He
2021-02-18  7:31     ` Baoquan He
2021-02-18  7:40     ` Baoquan He
2021-02-18  7:40       ` Baoquan He
2021-02-18  7:40       ` Baoquan He
2021-02-18  8:35   ` Baoquan He
2021-02-18  8:35     ` Baoquan He
2021-02-18  8:35     ` Baoquan He
2021-02-20  3:22     ` chenzhou
2021-02-20  3:22       ` chenzhou
2021-02-20  3:22       ` chenzhou
2021-01-30  7:10 ` [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux,usable-memory-range Chen Zhou
2021-01-30  7:10   ` [PATCH v14 10/11] arm64: kdump: add memory for devices by DT property linux, usable-memory-range Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10 ` [PATCH v14 11/11] kdump: update Documentation about crashkernel Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30  7:10   ` Chen Zhou
2021-01-30 17:53   ` Randy Dunlap
2021-01-30 17:53     ` Randy Dunlap
2021-01-30 17:53     ` Randy Dunlap
2021-02-04  1:53     ` chenzhou
2021-02-04  1:53       ` chenzhou
2021-02-04  1:53       ` chenzhou
2021-02-18  8:40   ` Baoquan He
2021-02-18  8:40     ` Baoquan He
2021-02-18  8:40     ` Baoquan He
2021-02-20  3:25     ` chenzhou
2021-02-20  3:25       ` chenzhou
2021-02-20  3:25       ` chenzhou
2021-02-08  6:46 ` [PATCH v14 00/11] support reserving crashkernel above 4G on arm64 kdump chenzhou
2021-02-08  6:46   ` chenzhou
2021-02-08  6:46   ` chenzhou

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