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* [PATCH 00/18] arm64: MMU enabled kexec relocation
@ 2021-05-27 15:05 Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 01/18] arm64: hyp-stub: Check the size of the HYP stub's vectors Pavel Tatashin
                   ` (17 more replies)
  0 siblings, 18 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Changelog:
v14:
	- Fixed a bug in "arm64: hyp-stub: Move elx_sync into the vectors"
	  that was noticed by Marc Zyngier
	- Merged with upstream
v13:
	- Fixed a hang on ThunderX2, thank you Pingfan Liu for reporting
	  the problem. In relocation function we need civac not ivac, we
	  need to clean data in addition to invalidating it.
	  Since I was using ThunderX2 machine I also measured the new
	  performance data on this large ARM64 server. The MMU improves
	  kexec relocation 190 times on this machine! (see below for
	  raw data). Saves 7.5s during CentOS kexec reboot.
v12:
	- A major change compared to previous version. Instead of using
	  contiguous VA range a copy of linear map is now used to perform
	  copying of segments during relocation as it was agreed in the
	  discussion of version 11 of this project.
	- In addition to using linear map, I also took several ideas from
	  James Morse to better organize the kexec relocation:
	  	1. skip relocation function entirely if that is not needed
		2. remove the PoC flushing function since it is not needed
		   anymore with MMU enabled.
v11:
	- Fixed missing KEXEC_CORE dependency for trans_pgd.c
	- Removed useless "if(rc) return rc" statement (thank you Tyler Hicks)
	- Another 12 patches were accepted into maintainer's get.
	  Re-based patches against:
	  https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
	  Branch: for-next/kexec
v10:
	- Addressed a lot of comments form James Morse and from  Marc Zyngier
	- Added review-by's
	- Synchronized with mainline

v9:	- 9 patches from previous series landed in upstream, so now series
	  is smaller
	- Added two patches from James Morse to address idmap issues for machines
	  with high physical addresses.
	- Addressed comments from Selin Dag about compiling issues. He also tested
	  my series and got similar performance results: ~60 ms instead of ~580 ms
	  with an initramfs size of ~120MB.
v8:
	- Synced with mainline to keep series up-to-date
v7:
	-- Addressed comments from James Morse
	- arm64: hibernate: pass the allocated pgdp to ttbr0
	  Removed "Fixes" tag, and added Added Reviewed-by: James Morse
	- arm64: hibernate: check pgd table allocation
	  Sent out as a standalone patch so it can be sent to stable
	  Series applies on mainline + this patch
	- arm64: hibernate: add trans_pgd public functions
	  Remove second allocation of tmp_pg_dir in swsusp_arch_resume
	  Added Reviewed-by: James Morse <james.morse@arm.com>
	- arm64: kexec: move relocation function setup and clean up
	  Fixed typo in commit log
	  Changed kern_reloc to phys_addr_t types.
	  Added explanation why kern_reloc is needed.
	  Split into four patches:
	  arm64: kexec: make dtb_mem always enabled
	  arm64: kexec: remove unnecessary debug prints
	  arm64: kexec: call kexec_image_info only once
	  arm64: kexec: move relocation function setup
	- arm64: kexec: add expandable argument to relocation function
	  Changed types of new arguments from unsigned long to phys_addr_t.
	  Changed offset prefix to KEXEC_*
	  Split into four patches:
	  arm64: kexec: cpu_soft_restart change argument types
	  arm64: kexec: arm64_relocate_new_kernel clean-ups
	  arm64: kexec: arm64_relocate_new_kernel don't use x0 as temp
	  arm64: kexec: add expandable argument to relocation function
	- arm64: kexec: configure trans_pgd page table for kexec
	  Added invalid entries into EL2 vector table
	  Removed KEXEC_EL2_VECTOR_TABLE_SIZE and KEXEC_EL2_VECTOR_TABLE_OFFSET
	  Copy relocation functions and table into separate pages
	  Changed types in kern_reloc_arg.
	  Split into three patches:
	  arm64: kexec: offset for relocation function
	  arm64: kexec: kexec EL2 vectors
	  arm64: kexec: configure trans_pgd page table for kexec
	- arm64: kexec: enable MMU during kexec relocation
	  Split into two patches:
	  arm64: kexec: enable MMU during kexec relocation
	  arm64: kexec: remove head from relocation argument
v6:
	- Sync with mainline tip
	- Added Acked's from Dave Young
v5:
	- Addressed comments from Matthias Brugger: added review-by's, improved
	  comments, and made cleanups to swsusp_arch_resume() in addition to
	  create_safe_exec_page().
	- Synced with mainline tip.
v4:
	- Addressed comments from James Morse.
	- Split "check pgd table allocation" into two patches, and moved to
	  the beginning of series  for simpler backport of the fixes.
	  Added "Fixes:" tags to commit logs.
	- Changed "arm64, hibernate:" to "arm64: hibernate:"
	- Added Reviewed-by's
	- Moved "add PUD_SECT_RDONLY" earlier in series to be with other
	  clean-ups
	- Added "Derived from:" to arch/arm64/mm/trans_pgd.c
	- Removed "flags" from trans_info
	- Changed .trans_alloc_page assumption to return zeroed page.
	- Simplify changes to trans_pgd_map_page(), by keeping the old
	  code.
	- Simplify changes to trans_pgd_create_copy, by keeping the old
	  code.
	- Removed: "add trans_pgd_create_empty"
	- replace init_mm with NULL, and keep using non "__" version of
	  populate functions.
v3:
	- Split changes to create_safe_exec_page() into several patches for
	  easier review as request by Mark Rutland. This is why this series
	  has 3 more patches.
	- Renamed trans_table to tans_pgd as agreed with Mark. The header
	  comment in trans_pgd.c explains that trans stands for
	  transitional page tables. Meaning they are used in transition
	  between two kernels.
v2:
	- Fixed hibernate bug reported by James Morse
	- Addressed comments from James Morse:
	  * More incremental changes to trans_table
	  * Removed TRANS_FORCEMAP
	  * Added kexec reboot data for image with 380M in size.

Enable MMU during kexec relocation in order to improve reboot performance.

If kexec functionality is used for a fast system update, with a minimal
downtime, the relocation of kernel + initramfs takes a significant portion
of reboot.

The reason for slow relocation is because it is done without MMU, and thus
not benefiting from D-Cache.

Performance data
----------------

Cavium ThunderX2:
Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M
MMU-disabled:
relocation	7.489539915s
MMU-enabled:
relocation	0.03946095s

Relocation performance is improved 190 times.

Broadcom Stingray:
For this experiment, the size of kernel plus initramfs is small, only 25M.
If initramfs was larger, than the improvements would be greater, as time
spent in relocation is proportional to the size of relocation.

MMU-disabled::
kernel shutdown	0.022131328s
relocation	0.440510736s
kernel startup	0.294706768s

Relocation was taking: 58.2% of reboot time

MMU-enabled:
kernel shutdown	0.032066576s
relocation	0.022158152s
kernel startup	0.296055880s

Now: Relocation takes 6.3% of reboot time

Total reboot is x2.16 times faster.

With bigger userland (fitImage 380M), the reboot time is improved by 3.57s,
and is reduced from 3.9s down to 0.33s

Previous approaches and discussions
-----------------------------------
v13: https://lore.kernel.org/lkml/20210408040537.2703241-1-pasha.tatashin@soleen.com
v12: https://lore.kernel.org/lkml/20210303002230.1083176-1-pasha.tatashin@soleen.com
v11: https://lore.kernel.org/lkml/20210127172706.617195-1-pasha.tatashin@soleen.com
v10: https://lore.kernel.org/linux-arm-kernel/20210125191923.1060122-1-pasha.tatashin@soleen.com
v9: https://lore.kernel.org/lkml/20200326032420.27220-1-pasha.tatashin@soleen.com
v8: https://lore.kernel.org/lkml/20191204155938.2279686-1-pasha.tatashin@soleen.com
v7: https://lore.kernel.org/lkml/20191016200034.1342308-1-pasha.tatashin@soleen.com
v6: https://lore.kernel.org/lkml/20191004185234.31471-1-pasha.tatashin@soleen.com
v5: https://lore.kernel.org/lkml/20190923203427.294286-1-pasha.tatashin@soleen.com
v4: https://lore.kernel.org/lkml/20190909181221.309510-1-pasha.tatashin@soleen.com
v3: https://lore.kernel.org/lkml/20190821183204.23576-1-pasha.tatashin@soleen.com
v2: https://lore.kernel.org/lkml/20190817024629.26611-1-pasha.tatashin@soleen.com
v1: https://lore.kernel.org/lkml/20190801152439.11363-1-pasha.tatashin@soleen.com

James Morse (3):
  arm64: hyp-stub: Check the size of the HYP stub's vectors
  arm64: hyp-stub: Move invalid vector entries into the vectors
  arm64: kexec: Use dcache ops macros instead of open-coding

Pavel Tatashin (14):
  arm64: hyp-stub: Move elx_sync into the vectors
  arm64: kernel: add helper for booted at EL2 and not VHE
  arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors
  arm64: hibernate: abstract ttrb0 setup function
  arm64: kexec: flush image and lists during kexec load time
  arm64: kexec: skip relocation code for inplace kexec
  arm64: kexec: pass kimage as the only argument to relocation function
  arm64: kexec: kexec may require EL2 vectors
  arm64: kexec: relocate in EL1 mode
  arm64: kexec: use ld script for relocation function
  arm64: kexec: install a copy of the linear-map
  arm64: kexec: keep MMU enabled during kexec relocation
  arm64: kexec: remove the pre-kexec PoC maintenance
  arm64: kexec: Remove cpu-reset.h

Pingfan Liu (1):
  arm64/mm: remove useless trans_pgd_map_page()

 arch/arm64/Kconfig                   |   2 +-
 arch/arm64/include/asm/assembler.h   |  31 ++++-
 arch/arm64/include/asm/kexec.h       |  12 ++
 arch/arm64/include/asm/mmu_context.h |  24 ++++
 arch/arm64/include/asm/sections.h    |   1 +
 arch/arm64/include/asm/trans_pgd.h   |   8 +-
 arch/arm64/include/asm/virt.h        |   8 ++
 arch/arm64/kernel/asm-offsets.c      |  11 ++
 arch/arm64/kernel/cpu-reset.S        |   7 +-
 arch/arm64/kernel/cpu-reset.h        |  32 -----
 arch/arm64/kernel/hibernate-asm.S    |  20 ----
 arch/arm64/kernel/hibernate.c        |  56 +++------
 arch/arm64/kernel/hyp-stub.S         |  90 +++++++-------
 arch/arm64/kernel/machine_kexec.c    | 168 +++++++++++++++------------
 arch/arm64/kernel/relocate_kernel.S  |  70 ++++++-----
 arch/arm64/kernel/sdei.c             |   2 +-
 arch/arm64/kernel/vmlinux.lds.S      |  19 +++
 arch/arm64/mm/trans_pgd.c            |  77 ++++--------
 18 files changed, 312 insertions(+), 326 deletions(-)
 delete mode 100644 arch/arm64/kernel/cpu-reset.h

-- 
2.25.1


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^ permalink raw reply	[flat|nested] 27+ messages in thread

* [PATCH 01/18] arm64: hyp-stub: Check the size of the HYP stub's vectors
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 02/18] arm64: hyp-stub: Move invalid vector entries into the vectors Pavel Tatashin
                   ` (16 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

From: James Morse <james.morse@arm.com>

Hibernate contains a set of temporary EL2 vectors used to 'park'
EL2 somewhere safe while all the memory is thrown in the air.
Making kexec do its relocations with the MMU on means they have to
be done at EL1, so EL2 has to be parked. This means yet another
set of vectors.

All these things do is HVC_SET_VECTORS and HVC_SOFT_RESTART, both
of which are implemented by the hyp-stub. Lets copy it instead
of re-inventing it.

To do this the hyp-stub's entrails need to be packed neatly inside
its 2K vectors.

Start by moving the final 2K alignment inside the end marker, and
add a build check that we didn't overflow 2K.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/hyp-stub.S | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 43d212618834..91aab4121463 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -41,9 +41,13 @@ SYM_CODE_START(__hyp_stub_vectors)
 	ventry	el1_irq_invalid			// IRQ 32-bit EL1
 	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
 	ventry	el1_error_invalid		// Error 32-bit EL1
+	.align 11
+SYM_INNER_LABEL(__hyp_stub_vectors_end, SYM_L_LOCAL)
 SYM_CODE_END(__hyp_stub_vectors)
 
-	.align 11
+# Check the __hyp_stub_vectors didn't overflow
+.org . - (__hyp_stub_vectors_end - __hyp_stub_vectors) + SZ_2K
+
 
 SYM_CODE_START_LOCAL(elx_sync)
 	cmp	x0, #HVC_SET_VECTORS
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 02/18] arm64: hyp-stub: Move invalid vector entries into the vectors
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 01/18] arm64: hyp-stub: Check the size of the HYP stub's vectors Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 03/18] arm64: hyp-stub: Move elx_sync " Pavel Tatashin
                   ` (15 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

From: James Morse <james.morse@arm.com>

Most of the hyp-stub's vector entries are invalid. These are each
a unique function that branches to itself. To move these into the
vectors, merge the ventry and invalid_vector macros and give each
one a unique name.

This means we can copy the hyp-stub as it is self contained within
its vectors.

Signed-off-by: James Morse <james.morse@arm.com>

[Fixed merging issues]

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/hyp-stub.S | 62 +++++++++++++++---------------------
 1 file changed, 26 insertions(+), 36 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 91aab4121463..18a97bee3779 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -16,31 +16,38 @@
 #include <asm/ptrace.h>
 #include <asm/virt.h>
 
+.macro invalid_vector	label
+SYM_CODE_START_LOCAL(\label)
+	.align 7
+	b	\label
+SYM_CODE_END(\label)
+.endm
+
 	.text
 	.pushsection	.hyp.text, "ax"
 
 	.align 11
 
 SYM_CODE_START(__hyp_stub_vectors)
-	ventry	el2_sync_invalid		// Synchronous EL2t
-	ventry	el2_irq_invalid			// IRQ EL2t
-	ventry	el2_fiq_invalid			// FIQ EL2t
-	ventry	el2_error_invalid		// Error EL2t
-
-	ventry	elx_sync			// Synchronous EL2h
-	ventry	el2_irq_invalid			// IRQ EL2h
-	ventry	el2_fiq_invalid			// FIQ EL2h
-	ventry	el2_error_invalid		// Error EL2h
-
-	ventry	elx_sync			// Synchronous 64-bit EL1
-	ventry	el1_irq_invalid			// IRQ 64-bit EL1
-	ventry	el1_fiq_invalid			// FIQ 64-bit EL1
-	ventry	el1_error_invalid		// Error 64-bit EL1
-
-	ventry	el1_sync_invalid		// Synchronous 32-bit EL1
-	ventry	el1_irq_invalid			// IRQ 32-bit EL1
-	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
-	ventry	el1_error_invalid		// Error 32-bit EL1
+	invalid_vector	hyp_stub_el2t_sync_invalid	// Synchronous EL2t
+	invalid_vector	hyp_stub_el2t_irq_invalid	// IRQ EL2t
+	invalid_vector	hyp_stub_el2t_fiq_invalid	// FIQ EL2t
+	invalid_vector	hyp_stub_el2t_error_invalid	// Error EL2t
+
+	ventry	elx_sync				// Synchronous EL2h
+	invalid_vector	hyp_stub_el2h_irq_invalid	// IRQ EL2h
+	invalid_vector	hyp_stub_el2h_fiq_invalid	// FIQ EL2h
+	invalid_vector	hyp_stub_el2h_error_invalid	// Error EL2h
+
+	ventry	elx_sync				// Synchronous 64-bit EL1
+	invalid_vector	hyp_stub_el1_irq_invalid	// IRQ 64-bit EL1
+	invalid_vector	hyp_stub_el1_fiq_invalid	// FIQ 64-bit EL1
+	invalid_vector	hyp_stub_el1_error_invalid	// Error 64-bit EL1
+
+	invalid_vector	hyp_stub_32b_el1_sync_invalid	// Synchronous 32-bit EL1
+	invalid_vector	hyp_stub_32b_el1_irq_invalid	// IRQ 32-bit EL1
+	invalid_vector	hyp_stub_32b_el1_fiq_invalid	// FIQ 32-bit EL1
+	invalid_vector	hyp_stub_32b_el1_error_invalid	// Error 32-bit EL1
 	.align 11
 SYM_INNER_LABEL(__hyp_stub_vectors_end, SYM_L_LOCAL)
 SYM_CODE_END(__hyp_stub_vectors)
@@ -174,23 +181,6 @@ SYM_CODE_END(enter_vhe)
 
 	.popsection
 
-.macro invalid_vector	label
-SYM_CODE_START_LOCAL(\label)
-	b \label
-SYM_CODE_END(\label)
-.endm
-
-	invalid_vector	el2_sync_invalid
-	invalid_vector	el2_irq_invalid
-	invalid_vector	el2_fiq_invalid
-	invalid_vector	el2_error_invalid
-	invalid_vector	el1_sync_invalid
-	invalid_vector	el1_irq_invalid
-	invalid_vector	el1_fiq_invalid
-	invalid_vector	el1_error_invalid
-
-	.popsection
-
 /*
  * __hyp_set_vectors: Call this after boot to set the initial hypervisor
  * vectors as part of hypervisor installation.  On an SMP system, this should
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 01/18] arm64: hyp-stub: Check the size of the HYP stub's vectors Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 02/18] arm64: hyp-stub: Move invalid vector entries into the vectors Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:54   ` Marc Zyngier
  2021-05-27 15:05 ` [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE Pavel Tatashin
                   ` (14 subsequent siblings)
  17 siblings, 1 reply; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

The hyp-stub's elx_sync code fits in the vector.

With this, all of the hyp-stubs behaviour is contained in its vectors.
This lets kexec and hibernate copy the hyp-stub when they need its
behaviour, instead of re-implementing it.

Co-developed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/hyp-stub.S | 64 +++++++++++++++++++-----------------
 1 file changed, 33 insertions(+), 31 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 18a97bee3779..86af6c4e52b9 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -21,6 +21,37 @@ SYM_CODE_START_LOCAL(\label)
 	.align 7
 	b	\label
 SYM_CODE_END(\label)
+.endm
+
+.macro elx_sync_vector	label
+SYM_CODE_START_LOCAL(\label)
+	.align 7
+	cmp	x0, #HVC_SET_VECTORS
+	b.ne	1f
+	msr	vbar_el2, x1
+	b	9f
+
+1:	cmp	x0, #HVC_VHE_RESTART
+	b.eq	mutate_to_vhe
+
+2:	cmp	x0, #HVC_SOFT_RESTART
+	b.ne	3f
+	mov	x0, x2
+	mov	x2, x4
+	mov	x4, x1
+	mov	x1, x3
+	br	x4				// no return
+
+3:	cmp	x0, #HVC_RESET_VECTORS
+	beq	9f				// Nothing to reset!
+
+	/* Someone called kvm_call_hyp() against the hyp-stub... */
+	mov_q	x0, HVC_STUB_ERR
+	eret
+
+9:	mov	x0, xzr
+	eret
+SYM_CODE_END(\label)
 .endm
 
 	.text
@@ -34,12 +65,12 @@ SYM_CODE_START(__hyp_stub_vectors)
 	invalid_vector	hyp_stub_el2t_fiq_invalid	// FIQ EL2t
 	invalid_vector	hyp_stub_el2t_error_invalid	// Error EL2t
 
-	ventry	elx_sync				// Synchronous EL2h
+	elx_sync_vector	el2h_sync			// Synchronous EL2h
 	invalid_vector	hyp_stub_el2h_irq_invalid	// IRQ EL2h
 	invalid_vector	hyp_stub_el2h_fiq_invalid	// FIQ EL2h
 	invalid_vector	hyp_stub_el2h_error_invalid	// Error EL2h
 
-	ventry	elx_sync				// Synchronous 64-bit EL1
+	elx_sync_vector	el1_sync			// Synchronous 64-bit EL1
 	invalid_vector	hyp_stub_el1_irq_invalid	// IRQ 64-bit EL1
 	invalid_vector	hyp_stub_el1_fiq_invalid	// FIQ 64-bit EL1
 	invalid_vector	hyp_stub_el1_error_invalid	// Error 64-bit EL1
@@ -55,35 +86,6 @@ SYM_CODE_END(__hyp_stub_vectors)
 # Check the __hyp_stub_vectors didn't overflow
 .org . - (__hyp_stub_vectors_end - __hyp_stub_vectors) + SZ_2K
 
-
-SYM_CODE_START_LOCAL(elx_sync)
-	cmp	x0, #HVC_SET_VECTORS
-	b.ne	1f
-	msr	vbar_el2, x1
-	b	9f
-
-1:	cmp	x0, #HVC_VHE_RESTART
-	b.eq	mutate_to_vhe
-
-2:	cmp	x0, #HVC_SOFT_RESTART
-	b.ne	3f
-	mov	x0, x2
-	mov	x2, x4
-	mov	x4, x1
-	mov	x1, x3
-	br	x4				// no return
-
-3:	cmp	x0, #HVC_RESET_VECTORS
-	beq	9f				// Nothing to reset!
-
-	/* Someone called kvm_call_hyp() against the hyp-stub... */
-	mov_q	x0, HVC_STUB_ERR
-	eret
-
-9:	mov	x0, xzr
-	eret
-SYM_CODE_END(elx_sync)
-
 // nVHE? No way! Give me the real thing!
 SYM_CODE_START_LOCAL(mutate_to_vhe)
 	// Sanity check: MMU *must* be off
-- 
2.25.1


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

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (2 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 03/18] arm64: hyp-stub: Move elx_sync " Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-06-01 12:38   ` Marc Zyngier
  2021-05-27 15:05 ` [PATCH 05/18] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors Pavel Tatashin
                   ` (13 subsequent siblings)
  17 siblings, 1 reply; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Replace places that contain logic like this:
	is_hyp_mode_available() && !is_kernel_in_hyp_mode()

With a dedicated boolean function  is_hyp_callable(). This will be needed
later in kexec in order to sooner switch back to EL2.

Suggested-by: James Morse <james.morse@arm.com>

[Fixed merging issues]

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/virt.h | 5 +++++
 arch/arm64/kernel/cpu-reset.h | 3 +--
 arch/arm64/kernel/hibernate.c | 9 +++------
 arch/arm64/kernel/sdei.c      | 2 +-
 4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 7379f35ae2c6..4216c8623538 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -128,6 +128,11 @@ static __always_inline bool is_protected_kvm_enabled(void)
 		return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
 }
 
+static inline bool is_hyp_callable(void)
+{
+	return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
+}
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* ! __ASM__VIRT_H */
diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
index 9a7b1262ef17..48d0ed48c147 100644
--- a/arch/arm64/kernel/cpu-reset.h
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -20,8 +20,7 @@ static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry,
 {
 	typeof(__cpu_soft_restart) *restart;
 
-	unsigned long el2_switch = !is_kernel_in_hyp_mode() &&
-		is_hyp_mode_available();
+	unsigned long el2_switch = is_hyp_callable();
 	restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
 
 	cpu_install_idmap();
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index b1cef371df2b..c764574a1acb 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -48,9 +48,6 @@
  */
 extern int in_suspend;
 
-/* Do we need to reset el2? */
-#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
-
 /* temporary el2 vectors in the __hibernate_exit_text section. */
 extern char hibernate_el2_vectors[];
 
@@ -125,7 +122,7 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
 	hdr->reenter_kernel	= _cpu_resume;
 
 	/* We can't use __hyp_get_vectors() because kvm may still be loaded */
-	if (el2_reset_needed())
+	if (is_hyp_callable())
 		hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
 	else
 		hdr->__hyp_stub_vectors = 0;
@@ -387,7 +384,7 @@ int swsusp_arch_suspend(void)
 		dcache_clean_range(__idmap_text_start, __idmap_text_end);
 
 		/* Clean kvm setup code to PoC? */
-		if (el2_reset_needed()) {
+		if (is_hyp_callable()) {
 			dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
 			dcache_clean_range(__hyp_text_start, __hyp_text_end);
 		}
@@ -482,7 +479,7 @@ int swsusp_arch_resume(void)
 	 *
 	 * We can skip this step if we booted at EL1, or are running with VHE.
 	 */
-	if (el2_reset_needed()) {
+	if (is_hyp_callable()) {
 		phys_addr_t el2_vectors = (phys_addr_t)hibernate_exit;
 		el2_vectors += hibernate_el2_vectors -
 			       __hibernate_exit_text_start;     /* offset */
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index 2c7ca449dd51..af0ac2f920cf 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -200,7 +200,7 @@ unsigned long sdei_arch_get_entry_point(int conduit)
 	 * dropped to EL1 because we don't support VHE, then we can't support
 	 * SDEI.
 	 */
-	if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
+	if (is_hyp_callable()) {
 		pr_err("Not supported on this hardware/boot configuration\n");
 		goto out_err;
 	}
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 05/18] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (3 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 06/18] arm64: hibernate: abstract ttrb0 setup function Pavel Tatashin
                   ` (12 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Users of trans_pgd may also need a copy of vector table because it is
also may be overwritten if a linear map can be overwritten.

Move setup of EL2 vectors from hibernate to trans_pgd, so it can be
later shared with kexec as well.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/trans_pgd.h |  3 +++
 arch/arm64/include/asm/virt.h      |  3 +++
 arch/arm64/kernel/hibernate.c      | 28 ++++++++++------------------
 arch/arm64/mm/trans_pgd.c          | 20 ++++++++++++++++++++
 4 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
index 5d08e5adf3d5..e0760e52d36d 100644
--- a/arch/arm64/include/asm/trans_pgd.h
+++ b/arch/arm64/include/asm/trans_pgd.h
@@ -36,4 +36,7 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
 int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 			 unsigned long *t0sz, void *page);
 
+int trans_pgd_copy_el2_vectors(struct trans_pgd_info *info,
+			       phys_addr_t *el2_vectors);
+
 #endif /* _ASM_TRANS_TABLE_H */
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 4216c8623538..bfbb66018114 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -67,6 +67,9 @@
  */
 extern u32 __boot_cpu_mode[2];
 
+extern char __hyp_stub_vectors[];
+#define ARM64_VECTOR_TABLE_LEN	SZ_2K
+
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
 void __hyp_reset_vectors(void);
 
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index c764574a1acb..0b8bad8bb6eb 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -48,12 +48,6 @@
  */
 extern int in_suspend;
 
-/* temporary el2 vectors in the __hibernate_exit_text section. */
-extern char hibernate_el2_vectors[];
-
-/* hyp-stub vectors, used to restore el2 during resume from hibernate. */
-extern char __hyp_stub_vectors[];
-
 /*
  * The logical cpu number we should resume on, initialised to a non-cpu
  * number.
@@ -428,6 +422,7 @@ int swsusp_arch_resume(void)
 	void *zero_page;
 	size_t exit_size;
 	pgd_t *tmp_pg_dir;
+	phys_addr_t el2_vectors;
 	void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *,
 					  void *, phys_addr_t, phys_addr_t);
 	struct trans_pgd_info trans_info = {
@@ -455,6 +450,14 @@ int swsusp_arch_resume(void)
 		return -ENOMEM;
 	}
 
+	if (is_hyp_callable()) {
+		rc = trans_pgd_copy_el2_vectors(&trans_info, &el2_vectors);
+		if (rc) {
+			pr_err("Failed to setup el2 vectors\n");
+			return rc;
+		}
+	}
+
 	exit_size = __hibernate_exit_text_end - __hibernate_exit_text_start;
 	/*
 	 * Copy swsusp_arch_suspend_exit() to a safe page. This will generate
@@ -467,25 +470,14 @@ int swsusp_arch_resume(void)
 		return rc;
 	}
 
-	/*
-	 * The hibernate exit text contains a set of el2 vectors, that will
-	 * be executed at el2 with the mmu off in order to reload hyp-stub.
-	 */
-	__flush_dcache_area(hibernate_exit, exit_size);
-
 	/*
 	 * KASLR will cause the el2 vectors to be in a different location in
 	 * the resumed kernel. Load hibernate's temporary copy into el2.
 	 *
 	 * We can skip this step if we booted at EL1, or are running with VHE.
 	 */
-	if (is_hyp_callable()) {
-		phys_addr_t el2_vectors = (phys_addr_t)hibernate_exit;
-		el2_vectors += hibernate_el2_vectors -
-			       __hibernate_exit_text_start;     /* offset */
-
+	if (is_hyp_callable())
 		__hyp_set_vectors(el2_vectors);
-	}
 
 	hibernate_exit(virt_to_phys(tmp_pg_dir), resume_hdr.ttbr1_el1,
 		       resume_hdr.reenter_kernel, restore_pblist,
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 527f0a39c3da..61549451ed3a 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -322,3 +322,23 @@ int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 
 	return 0;
 }
+
+/*
+ * Create a copy of the vector table so we can call HVC_SET_VECTORS or
+ * HVC_SOFT_RESTART from contexts where the table may be overwritten.
+ */
+int trans_pgd_copy_el2_vectors(struct trans_pgd_info *info,
+			       phys_addr_t *el2_vectors)
+{
+	void *hyp_stub = trans_alloc(info);
+
+	if (!hyp_stub)
+		return -ENOMEM;
+	*el2_vectors = virt_to_phys(hyp_stub);
+	memcpy(hyp_stub, &__hyp_stub_vectors, ARM64_VECTOR_TABLE_LEN);
+	__flush_icache_range((unsigned long)hyp_stub,
+			     (unsigned long)hyp_stub + ARM64_VECTOR_TABLE_LEN);
+	__flush_dcache_area(hyp_stub, ARM64_VECTOR_TABLE_LEN);
+
+	return 0;
+}
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 06/18] arm64: hibernate: abstract ttrb0 setup function
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (4 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 05/18] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 07/18] arm64: kexec: flush image and lists during kexec load time Pavel Tatashin
                   ` (11 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Currently, only hibernate sets custom ttbr0 with safe idmaped function.
Kexec, is also going to be using this functinality when relocation code
is going to be idmapped.

Move the setup seqeuence to a dedicated cpu_install_ttbr0() for custom
ttbr0.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/mmu_context.h | 24 ++++++++++++++++++++++++
 arch/arm64/kernel/hibernate.c        | 21 +--------------------
 2 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index d3cef9133539..85eb92a2ffcb 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -115,6 +115,30 @@ static inline void cpu_install_idmap(void)
 	cpu_switch_mm(lm_alias(idmap_pg_dir), &init_mm);
 }
 
+/*
+ * Load our new page tables. A strict BBM approach requires that we ensure that
+ * TLBs are free of any entries that may overlap with the global mappings we are
+ * about to install.
+ *
+ * For a real hibernate/resume/kexec cycle TTBR0 currently points to a zero
+ * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI runtime
+ * services), while for a userspace-driven test_resume cycle it points to
+ * userspace page tables (and we must point it at a zero page ourselves).
+ *
+ * We change T0SZ as part of installing the idmap. This is undone by
+ * cpu_uninstall_idmap() in __cpu_suspend_exit().
+ */
+static inline void cpu_install_ttbr0(phys_addr_t ttbr0, unsigned long t0sz)
+{
+	cpu_set_reserved_ttbr0();
+	local_flush_tlb_all();
+	__cpu_set_tcr_t0sz(t0sz);
+
+	/* avoid cpu_switch_mm() and its SW-PAN and CNP interactions */
+	write_sysreg(ttbr0, ttbr0_el1);
+	isb();
+}
+
 /*
  * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD,
  * avoiding the possibility of conflicting TLB entries being allocated.
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 0b8bad8bb6eb..ded5115bcb63 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -206,26 +206,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
 	if (rc)
 		return rc;
 
-	/*
-	 * Load our new page tables. A strict BBM approach requires that we
-	 * ensure that TLBs are free of any entries that may overlap with the
-	 * global mappings we are about to install.
-	 *
-	 * For a real hibernate/resume cycle TTBR0 currently points to a zero
-	 * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI
-	 * runtime services), while for a userspace-driven test_resume cycle it
-	 * points to userspace page tables (and we must point it at a zero page
-	 * ourselves).
-	 *
-	 * We change T0SZ as part of installing the idmap. This is undone by
-	 * cpu_uninstall_idmap() in __cpu_suspend_exit().
-	 */
-	cpu_set_reserved_ttbr0();
-	local_flush_tlb_all();
-	__cpu_set_tcr_t0sz(t0sz);
-	write_sysreg(trans_ttbr0, ttbr0_el1);
-	isb();
-
+	cpu_install_ttbr0(trans_ttbr0, t0sz);
 	*phys_dst_addr = virt_to_phys(page);
 
 	return 0;
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 07/18] arm64: kexec: flush image and lists during kexec load time
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (5 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 06/18] arm64: hibernate: abstract ttrb0 setup function Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 08/18] arm64: kexec: skip relocation code for inplace kexec Pavel Tatashin
                   ` (10 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Currently, during kexec load we are copying relocation function and
flushing it. However, we can also flush kexec relocation buffers and
if new kernel image is already in place (i.e. crash kernel), we can
also flush the new kernel image itself.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/machine_kexec.c | 49 +++++++++++++++----------------
 1 file changed, 23 insertions(+), 26 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 90a335c74442..3a034bc25709 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -59,23 +59,6 @@ void machine_kexec_cleanup(struct kimage *kimage)
 	/* Empty routine needed to avoid build errors. */
 }
 
-int machine_kexec_post_load(struct kimage *kimage)
-{
-	void *reloc_code = page_to_virt(kimage->control_code_page);
-
-	memcpy(reloc_code, arm64_relocate_new_kernel,
-	       arm64_relocate_new_kernel_size);
-	kimage->arch.kern_reloc = __pa(reloc_code);
-	kexec_image_info(kimage);
-
-	/* Flush the reloc_code in preparation for its execution. */
-	__flush_dcache_area(reloc_code, arm64_relocate_new_kernel_size);
-	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
-			   arm64_relocate_new_kernel_size);
-
-	return 0;
-}
-
 /**
  * machine_kexec_prepare - Prepare for a kexec reboot.
  *
@@ -152,6 +135,29 @@ static void kexec_segment_flush(const struct kimage *kimage)
 	}
 }
 
+int machine_kexec_post_load(struct kimage *kimage)
+{
+	void *reloc_code = page_to_virt(kimage->control_code_page);
+
+	/* If in place flush new kernel image, else flush lists and buffers */
+	if (kimage->head & IND_DONE)
+		kexec_segment_flush(kimage);
+	else
+		kexec_list_flush(kimage);
+
+	memcpy(reloc_code, arm64_relocate_new_kernel,
+	       arm64_relocate_new_kernel_size);
+	kimage->arch.kern_reloc = __pa(reloc_code);
+	kexec_image_info(kimage);
+
+	/* Flush the reloc_code in preparation for its execution. */
+	__flush_dcache_area(reloc_code, arm64_relocate_new_kernel_size);
+	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
+			   arm64_relocate_new_kernel_size);
+
+	return 0;
+}
+
 /**
  * machine_kexec - Do the kexec reboot.
  *
@@ -169,13 +175,6 @@ void machine_kexec(struct kimage *kimage)
 	WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
 		"Some CPUs may be stale, kdump will be unreliable.\n");
 
-	/* Flush the kimage list and its buffers. */
-	kexec_list_flush(kimage);
-
-	/* Flush the new image if already in place. */
-	if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE))
-		kexec_segment_flush(kimage);
-
 	pr_info("Bye!\n");
 
 	local_daif_mask();
@@ -250,8 +249,6 @@ void arch_kexec_protect_crashkres(void)
 {
 	int i;
 
-	kexec_segment_flush(kexec_crash_image);
-
 	for (i = 0; i < kexec_crash_image->nr_segments; i++)
 		set_memory_valid(
 			__phys_to_virt(kexec_crash_image->segment[i].mem),
-- 
2.25.1


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

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 08/18] arm64: kexec: skip relocation code for inplace kexec
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (6 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 07/18] arm64: kexec: flush image and lists during kexec load time Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 09/18] arm64: kexec: Use dcache ops macros instead of open-coding Pavel Tatashin
                   ` (9 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

In case of kdump or when segments are already in place the relocation
is not needed, therefore the setup of relocation function and call to
it can be skipped.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Suggested-by: James Morse <james.morse@arm.com>
---
 arch/arm64/kernel/machine_kexec.c   | 34 ++++++++++++++++++-----------
 arch/arm64/kernel/relocate_kernel.S |  3 ---
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 3a034bc25709..bde623805866 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -139,21 +139,23 @@ int machine_kexec_post_load(struct kimage *kimage)
 {
 	void *reloc_code = page_to_virt(kimage->control_code_page);
 
-	/* If in place flush new kernel image, else flush lists and buffers */
-	if (kimage->head & IND_DONE)
+	/* If in place, relocation is not used, only flush next kernel */
+	if (kimage->head & IND_DONE) {
 		kexec_segment_flush(kimage);
-	else
-		kexec_list_flush(kimage);
+		kexec_image_info(kimage);
+		return 0;
+	}
 
 	memcpy(reloc_code, arm64_relocate_new_kernel,
 	       arm64_relocate_new_kernel_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
-	kexec_image_info(kimage);
 
 	/* Flush the reloc_code in preparation for its execution. */
 	__flush_dcache_area(reloc_code, arm64_relocate_new_kernel_size);
 	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
 			   arm64_relocate_new_kernel_size);
+	kexec_list_flush(kimage);
+	kexec_image_info(kimage);
 
 	return 0;
 }
@@ -180,19 +182,25 @@ void machine_kexec(struct kimage *kimage)
 	local_daif_mask();
 
 	/*
-	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
-	 * transfer control to the kern_reloc which contains a copy of
-	 * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
-	 * uses physical addressing to relocate the new image to its final
-	 * position and transfers control to the image entry point when the
-	 * relocation is complete.
+	 * Both restart and cpu_soft_restart will shutdown the MMU, disable data
+	 * caches. However, restart will start new kernel or purgatory directly,
+	 * cpu_soft_restart will transfer control to arm64_relocate_new_kernel
 	 * In kexec case, kimage->start points to purgatory assuming that
 	 * kernel entry and dtb address are embedded in purgatory by
 	 * userspace (kexec-tools).
 	 * In kexec_file case, the kernel starts directly without purgatory.
 	 */
-	cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start,
-			 kimage->arch.dtb_mem);
+	if (kimage->head & IND_DONE) {
+		typeof(__cpu_soft_restart) *restart;
+
+		cpu_install_idmap();
+		restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
+		restart(is_hyp_callable(), kimage->start, kimage->arch.dtb_mem,
+			0, 0);
+	} else {
+		cpu_soft_restart(kimage->arch.kern_reloc, kimage->head,
+				 kimage->start, kimage->arch.dtb_mem);
+	}
 
 	BUG(); /* Should never get here. */
 }
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index b78ea5de97a4..8058fabe0a76 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -32,8 +32,6 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	mov	x16, x0				/* x16 = kimage_head */
 	mov	x14, xzr			/* x14 = entry ptr */
 	mov	x13, xzr			/* x13 = copy dest */
-	/* Check if the new image needs relocation. */
-	tbnz	x16, IND_DONE_BIT, .Ldone
 	raw_dcache_line_size x15, x1		/* x15 = dcache line size */
 .Lloop:
 	and	x12, x16, PAGE_MASK		/* x12 = addr */
@@ -65,7 +63,6 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 .Lnext:
 	ldr	x16, [x14], #8			/* entry = *ptr++ */
 	tbz	x16, IND_DONE_BIT, .Lloop	/* while (!(entry & DONE)) */
-.Ldone:
 	/* wait for writes from copy_page to finish */
 	dsb	nsh
 	ic	iallu
-- 
2.25.1


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

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 09/18] arm64: kexec: Use dcache ops macros instead of open-coding
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (7 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 08/18] arm64: kexec: skip relocation code for inplace kexec Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 10/18] arm64: kexec: pass kimage as the only argument to relocation function Pavel Tatashin
                   ` (8 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

From: James Morse <james.morse@arm.com>

kexec does dcache maintenance when it re-writes all memory. Our
dcache_by_line_op macro depends on reading the sanitised DminLine
from memory. Kexec may have overwritten this, so open-codes the
sequence.

dcache_by_line_op is a whole set of macros, it uses dcache_line_size
which uses read_ctr for the sanitsed DminLine. Reading the DminLine
is the first thing the dcache_by_line_op does.

Rename dcache_by_line_op dcache_by_myline_op and take DminLine as
an argument. Kexec can now use the slightly smaller macro.

This makes up-coming changes to the dcache maintenance easier on
the eye.

Code generated by the existing callers is unchanged.

Signed-off-by: James Morse <james.morse@arm.com>

[Fixed merging issues]

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/assembler.h  | 12 ++++++++----
 arch/arm64/kernel/relocate_kernel.S | 13 +++----------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 8418c1bd8f04..f1367863d995 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -393,10 +393,9 @@ alternative_else
 alternative_endif
 	.endm
 
-	.macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
-	dcache_line_size \tmp1, \tmp2
+	.macro dcache_by_myline_op op, domain, kaddr, size, linesz, tmp2
 	add	\size, \kaddr, \size
-	sub	\tmp2, \tmp1, #1
+	sub	\tmp2, \linesz, #1
 	bic	\kaddr, \kaddr, \tmp2
 9998:
 	.ifc	\op, cvau
@@ -416,12 +415,17 @@ alternative_endif
 	.endif
 	.endif
 	.endif
-	add	\kaddr, \kaddr, \tmp1
+	add	\kaddr, \kaddr, \linesz
 	cmp	\kaddr, \size
 	b.lo	9998b
 	dsb	\domain
 	.endm
 
+	.macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
+	dcache_line_size \tmp1, \tmp2
+	dcache_by_myline_op \op, \domain, \kaddr, \size, \tmp1, \tmp2
+	.endm
+
 /*
  * Macro to perform an instruction cache maintenance for the interval
  * [start, end)
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 8058fabe0a76..718037bef560 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -41,16 +41,9 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	tbz	x16, IND_SOURCE_BIT, .Ltest_indirection
 
 	/* Invalidate dest page to PoC. */
-	mov     x2, x13
-	add     x20, x2, #PAGE_SIZE
-	sub     x1, x15, #1
-	bic     x2, x2, x1
-2:	dc      ivac, x2
-	add     x2, x2, x15
-	cmp     x2, x20
-	b.lo    2b
-	dsb     sy
-
+	mov	x2, x13
+	mov	x1, #PAGE_SIZE
+	dcache_by_myline_op ivac, sy, x2, x1, x15, x20
 	copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8
 	b	.Lnext
 .Ltest_indirection:
-- 
2.25.1


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

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 10/18] arm64: kexec: pass kimage as the only argument to relocation function
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (8 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 09/18] arm64: kexec: Use dcache ops macros instead of open-coding Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 11/18] arm64: kexec: kexec may require EL2 vectors Pavel Tatashin
                   ` (7 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Currently, kexec relocation function (arm64_relocate_new_kernel) accepts
the following arguments:

head:		start of array that contains relocation information.
entry:		entry point for new kernel or purgatory.
dtb_mem:	first and only argument to entry.

The number of arguments cannot be easily expended, because this
function is also called from HVC_SOFT_RESTART, which preserves only
three arguments. And, also arm64_relocate_new_kernel is written in
assembly but called without stack, thus no place to move extra arguments
to free registers.

Soon, we will need to pass more arguments: once we enable MMU we
will need to pass information about page tables.

Pass kimage to arm64_relocate_new_kernel, and teach it to get the
required fields from kimage.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/asm-offsets.c     |  7 +++++++
 arch/arm64/kernel/machine_kexec.c   |  6 ++++--
 arch/arm64/kernel/relocate_kernel.S | 10 ++++------
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 0cb34ccb6e73..92c2ed846730 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -9,6 +9,7 @@
 
 #include <linux/arm_sdei.h>
 #include <linux/sched.h>
+#include <linux/kexec.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 #include <linux/kvm_host.h>
@@ -155,6 +156,12 @@ int main(void)
   DEFINE(PTRAUTH_USER_KEY_APIA,		offsetof(struct ptrauth_keys_user, apia));
   DEFINE(PTRAUTH_KERNEL_KEY_APIA,	offsetof(struct ptrauth_keys_kernel, apia));
   BLANK();
+#endif
+#ifdef CONFIG_KEXEC_CORE
+  DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));
+  DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));
+  DEFINE(KIMAGE_START,			offsetof(struct kimage, start));
+  BLANK();
 #endif
   return 0;
 }
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index bde623805866..76a757954a70 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -83,6 +83,8 @@ static void kexec_list_flush(struct kimage *kimage)
 {
 	kimage_entry_t *entry;
 
+	__flush_dcache_area(kimage, sizeof(*kimage));
+
 	for (entry = &kimage->head; ; entry++) {
 		unsigned int flag;
 		void *addr;
@@ -198,8 +200,8 @@ void machine_kexec(struct kimage *kimage)
 		restart(is_hyp_callable(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
-		cpu_soft_restart(kimage->arch.kern_reloc, kimage->head,
-				 kimage->start, kimage->arch.dtb_mem);
+		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),
+				 0, 0);
 	}
 
 	BUG(); /* Should never get here. */
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 718037bef560..36b4496524c3 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -27,9 +27,7 @@
  */
 SYM_CODE_START(arm64_relocate_new_kernel)
 	/* Setup the list loop variables. */
-	mov	x18, x2				/* x18 = dtb address */
-	mov	x17, x1				/* x17 = kimage_start */
-	mov	x16, x0				/* x16 = kimage_head */
+	ldr	x16, [x0, #KIMAGE_HEAD]		/* x16 = kimage_head */
 	mov	x14, xzr			/* x14 = entry ptr */
 	mov	x13, xzr			/* x13 = copy dest */
 	raw_dcache_line_size x15, x1		/* x15 = dcache line size */
@@ -63,12 +61,12 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	isb
 
 	/* Start new image. */
-	mov	x0, x18
+	ldr	x4, [x0, #KIMAGE_START]		/* relocation start */
+	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
 	mov	x1, xzr
 	mov	x2, xzr
 	mov	x3, xzr
-	br	x17
-
+	br	x4
 SYM_CODE_END(arm64_relocate_new_kernel)
 
 .align 3	/* To keep the 64-bit values below naturally aligned. */
-- 
2.25.1


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

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 11/18] arm64: kexec: kexec may require EL2 vectors
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (9 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 10/18] arm64: kexec: pass kimage as the only argument to relocation function Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 12/18] arm64: kexec: relocate in EL1 mode Pavel Tatashin
                   ` (6 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

If we have a EL2 mode without VHE, the EL2 vectors are needed in order
to switch to EL2 and jump to new world with hypervisor privileges.

In preporation to MMU enabled relocation, configure our EL2 table now.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/Kconfig                |  2 +-
 arch/arm64/include/asm/kexec.h    |  1 +
 arch/arm64/kernel/asm-offsets.c   |  1 +
 arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++
 4 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9f1d8566bbf9..e775e6fb03c5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1148,7 +1148,7 @@ config CRASH_DUMP
 
 config TRANS_TABLE
 	def_bool y
-	depends on HIBERNATION
+	depends on HIBERNATION || KEXEC_CORE
 
 config XEN_DOM0
 	def_bool y
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 00dbcc71aeb2..753a1c398898 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -96,6 +96,7 @@ struct kimage_arch {
 	void *dtb;
 	phys_addr_t dtb_mem;
 	phys_addr_t kern_reloc;
+	phys_addr_t el2_vectors;
 };
 
 #ifdef CONFIG_KEXEC_FILE
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 92c2ed846730..ee37d0e0fb6d 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -159,6 +159,7 @@ int main(void)
 #endif
 #ifdef CONFIG_KEXEC_CORE
   DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));
+  DEFINE(KIMAGE_ARCH_EL2_VECTORS,	offsetof(struct kimage, arch.el2_vectors));
   DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));
   DEFINE(KIMAGE_START,			offsetof(struct kimage, start));
   BLANK();
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 76a757954a70..9f74791cb1d0 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -20,6 +20,7 @@
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/page.h>
+#include <asm/trans_pgd.h>
 
 #include "cpu-reset.h"
 
@@ -42,7 +43,9 @@ static void _kexec_image_info(const char *func, int line,
 	pr_debug("    start:       %lx\n", kimage->start);
 	pr_debug("    head:        %lx\n", kimage->head);
 	pr_debug("    nr_segments: %lu\n", kimage->nr_segments);
+	pr_debug("    dtb_mem: %pa\n", &kimage->arch.dtb_mem);
 	pr_debug("    kern_reloc: %pa\n", &kimage->arch.kern_reloc);
+	pr_debug("    el2_vectors: %pa\n", &kimage->arch.el2_vectors);
 
 	for (i = 0; i < kimage->nr_segments; i++) {
 		pr_debug("      segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
@@ -137,9 +140,27 @@ static void kexec_segment_flush(const struct kimage *kimage)
 	}
 }
 
+/* Allocates pages for kexec page table */
+static void *kexec_page_alloc(void *arg)
+{
+	struct kimage *kimage = (struct kimage *)arg;
+	struct page *page = kimage_alloc_control_pages(kimage, 0);
+
+	if (!page)
+		return NULL;
+
+	memset(page_address(page), 0, PAGE_SIZE);
+
+	return page_address(page);
+}
+
 int machine_kexec_post_load(struct kimage *kimage)
 {
 	void *reloc_code = page_to_virt(kimage->control_code_page);
+	struct trans_pgd_info info = {
+		.trans_alloc_page	= kexec_page_alloc,
+		.trans_alloc_arg	= kimage,
+	};
 
 	/* If in place, relocation is not used, only flush next kernel */
 	if (kimage->head & IND_DONE) {
@@ -148,6 +169,14 @@ int machine_kexec_post_load(struct kimage *kimage)
 		return 0;
 	}
 
+	kimage->arch.el2_vectors = 0;
+	if (is_hyp_callable()) {
+		int rc = trans_pgd_copy_el2_vectors(&info,
+						    &kimage->arch.el2_vectors);
+		if (rc)
+			return rc;
+	}
+
 	memcpy(reloc_code, arm64_relocate_new_kernel,
 	       arm64_relocate_new_kernel_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
@@ -200,6 +229,8 @@ void machine_kexec(struct kimage *kimage)
 		restart(is_hyp_callable(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
+		if (is_hyp_callable())
+			__hyp_set_vectors(kimage->arch.el2_vectors);
 		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),
 				 0, 0);
 	}
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 12/18] arm64: kexec: relocate in EL1 mode
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (10 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 11/18] arm64: kexec: kexec may require EL2 vectors Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 13/18] arm64: kexec: use ld script for relocation function Pavel Tatashin
                   ` (5 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Since we are going to keep MMU enabled during relocation, we need to
keep EL1 mode throughout the relocation.

Keep EL1 enabled, and switch EL2 only before enterying the new world.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/cpu-reset.h       |  3 +--
 arch/arm64/kernel/machine_kexec.c   |  4 ++--
 arch/arm64/kernel/relocate_kernel.S | 13 +++++++++++--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
index 48d0ed48c147..296abbac7192 100644
--- a/arch/arm64/kernel/cpu-reset.h
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -20,11 +20,10 @@ static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry,
 {
 	typeof(__cpu_soft_restart) *restart;
 
-	unsigned long el2_switch = is_hyp_callable();
 	restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
 
 	cpu_install_idmap();
-	restart(el2_switch, entry, arg0, arg1, arg2);
+	restart(0, entry, arg0, arg1, arg2);
 	unreachable();
 }
 
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 9f74791cb1d0..c9993f029262 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -231,8 +231,8 @@ void machine_kexec(struct kimage *kimage)
 	} else {
 		if (is_hyp_callable())
 			__hyp_set_vectors(kimage->arch.el2_vectors);
-		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),
-				 0, 0);
+		cpu_soft_restart(kimage->arch.kern_reloc,
+				 virt_to_phys(kimage), 0, 0);
 	}
 
 	BUG(); /* Should never get here. */
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 36b4496524c3..df023b82544b 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -13,6 +13,7 @@
 #include <asm/kexec.h>
 #include <asm/page.h>
 #include <asm/sysreg.h>
+#include <asm/virt.h>
 
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
@@ -61,12 +62,20 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	isb
 
 	/* Start new image. */
+	ldr	x1, [x0, #KIMAGE_ARCH_EL2_VECTORS]	/* relocation start */
+	cbz	x1, .Lel1
+	ldr	x1, [x0, #KIMAGE_START]		/* relocation start */
+	ldr	x2, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
+	mov	x3, xzr
+	mov	x4, xzr
+	mov     x0, #HVC_SOFT_RESTART
+	hvc	#0				/* Jumps from el2 */
+.Lel1:
 	ldr	x4, [x0, #KIMAGE_START]		/* relocation start */
 	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
-	mov	x1, xzr
 	mov	x2, xzr
 	mov	x3, xzr
-	br	x4
+	br	x4				/* Jumps from el1 */
 SYM_CODE_END(arm64_relocate_new_kernel)
 
 .align 3	/* To keep the 64-bit values below naturally aligned. */
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 13/18] arm64: kexec: use ld script for relocation function
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (11 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 12/18] arm64: kexec: relocate in EL1 mode Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 14/18] arm64: kexec: install a copy of the linear-map Pavel Tatashin
                   ` (4 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Currently, relocation code declares start and end variables
which are used to compute its size.

The better way to do this is to use ld script incited, and put relocation
function in its own section.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/sections.h   |  1 +
 arch/arm64/kernel/machine_kexec.c   | 14 ++++++--------
 arch/arm64/kernel/relocate_kernel.S | 15 ++-------------
 arch/arm64/kernel/vmlinux.lds.S     | 19 +++++++++++++++++++
 4 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index e4ad9db53af1..152cb35bf9df 100644
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -21,5 +21,6 @@ extern char __exittext_begin[], __exittext_end[];
 extern char __irqentry_text_start[], __irqentry_text_end[];
 extern char __mmuoff_data_start[], __mmuoff_data_end[];
 extern char __entry_tramp_text_start[], __entry_tramp_text_end[];
+extern char __relocate_new_kernel_start[], __relocate_new_kernel_end[];
 
 #endif /* __ASM_SECTIONS_H */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index c9993f029262..675d27d7aea4 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -20,14 +20,11 @@
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/page.h>
+#include <asm/sections.h>
 #include <asm/trans_pgd.h>
 
 #include "cpu-reset.h"
 
-/* Global variables for the arm64_relocate_new_kernel routine. */
-extern const unsigned char arm64_relocate_new_kernel[];
-extern const unsigned long arm64_relocate_new_kernel_size;
-
 /**
  * kexec_image_info - For debugging output.
  */
@@ -157,6 +154,7 @@ static void *kexec_page_alloc(void *arg)
 int machine_kexec_post_load(struct kimage *kimage)
 {
 	void *reloc_code = page_to_virt(kimage->control_code_page);
+	long reloc_size;
 	struct trans_pgd_info info = {
 		.trans_alloc_page	= kexec_page_alloc,
 		.trans_alloc_arg	= kimage,
@@ -177,14 +175,14 @@ int machine_kexec_post_load(struct kimage *kimage)
 			return rc;
 	}
 
-	memcpy(reloc_code, arm64_relocate_new_kernel,
-	       arm64_relocate_new_kernel_size);
+	reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
+	memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
 
 	/* Flush the reloc_code in preparation for its execution. */
-	__flush_dcache_area(reloc_code, arm64_relocate_new_kernel_size);
+	__flush_dcache_area(reloc_code, reloc_size);
 	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
-			   arm64_relocate_new_kernel_size);
+			   reloc_size);
 	kexec_list_flush(kimage);
 	kexec_image_info(kimage);
 
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index df023b82544b..7a600ba33ae1 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -15,6 +15,7 @@
 #include <asm/sysreg.h>
 #include <asm/virt.h>
 
+.pushsection    ".kexec_relocate.text", "ax"
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
  *
@@ -77,16 +78,4 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	mov	x3, xzr
 	br	x4				/* Jumps from el1 */
 SYM_CODE_END(arm64_relocate_new_kernel)
-
-.align 3	/* To keep the 64-bit values below naturally aligned. */
-
-.Lcopy_end:
-.org	KEXEC_CONTROL_PAGE_SIZE
-
-/*
- * arm64_relocate_new_kernel_size - Number of bytes to copy to the
- * control_code_page.
- */
-.globl arm64_relocate_new_kernel_size
-arm64_relocate_new_kernel_size:
-	.quad	.Lcopy_end - arm64_relocate_new_kernel
+.popsection
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 709d2c433c5e..9479d66f03bf 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -63,6 +63,7 @@
 #include <asm-generic/vmlinux.lds.h>
 #include <asm/cache.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kexec.h>
 #include <asm/memory.h>
 #include <asm/page.h>
 
@@ -100,6 +101,16 @@ jiffies = jiffies_64;
 #define HIBERNATE_TEXT
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+#define KEXEC_TEXT					\
+	. = ALIGN(SZ_4K);				\
+	__relocate_new_kernel_start = .;		\
+	*(.kexec_relocate.text)				\
+	__relocate_new_kernel_end = .;
+#else
+#define KEXEC_TEXT
+#endif
+
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 #define TRAMP_TEXT					\
 	. = ALIGN(PAGE_SIZE);				\
@@ -160,6 +171,7 @@ SECTIONS
 			HYPERVISOR_TEXT
 			IDMAP_TEXT
 			HIBERNATE_TEXT
+			KEXEC_TEXT
 			TRAMP_TEXT
 			*(.fixup)
 			*(.gnu.warning)
@@ -348,3 +360,10 @@ ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,
 ASSERT(swapper_pg_dir - tramp_pg_dir == TRAMP_SWAPPER_OFFSET,
        "TRAMP_SWAPPER_OFFSET is wrong!")
 #endif
+
+#ifdef CONFIG_KEXEC_CORE
+/* kexec relocation code should fit into one KEXEC_CONTROL_PAGE_SIZE */
+ASSERT(__relocate_new_kernel_end - (__relocate_new_kernel_start & ~(SZ_4K - 1))
+	<= SZ_4K, "kexec relocation code is too big or misaligned")
+ASSERT(KEXEC_CONTROL_PAGE_SIZE >= SZ_4K, "KEXEC_CONTROL_PAGE_SIZE is brokern")
+#endif
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 14/18] arm64: kexec: install a copy of the linear-map
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (12 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 13/18] arm64: kexec: use ld script for relocation function Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 15/18] arm64: kexec: keep MMU enabled during kexec relocation Pavel Tatashin
                   ` (3 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

To perform the kexec relocations with the MMU enabled, we need a copy
of the linear map.

Create one, and install it from the relocation code. This has to be done
from the assembly code as it will be idmapped with TTBR0. The kernel
runs in TTRB1, so can't use the break-before-make sequence on the mapping
it is executing from.

The makes no difference yet as the relocation code runs with the MMU
disabled.

Co-developed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/assembler.h  | 19 +++++++++++++++++++
 arch/arm64/include/asm/kexec.h      |  2 ++
 arch/arm64/kernel/asm-offsets.c     |  2 ++
 arch/arm64/kernel/hibernate-asm.S   | 20 --------------------
 arch/arm64/kernel/machine_kexec.c   | 16 ++++++++++++++--
 arch/arm64/kernel/relocate_kernel.S |  3 +++
 6 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index f1367863d995..7f268bfa98c6 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -447,6 +447,25 @@ USER(\label, ic	ivau, \tmp2)			// invalidate I line PoU
 	isb
 	.endm
 
+/*
+ * To prevent the possibility of old and new partial table walks being visible
+ * in the tlb, switch the ttbr to a zero page when we invalidate the old
+ * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
+ * Even switching to our copied tables will cause a changed output address at
+ * each stage of the walk.
+ */
+	.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2
+	phys_to_ttbr \tmp, \zero_page
+	msr	ttbr1_el1, \tmp
+	isb
+	tlbi	vmalle1
+	dsb	nsh
+	phys_to_ttbr \tmp, \page_table
+	offset_ttbr1 \tmp, \tmp2
+	msr	ttbr1_el1, \tmp
+	isb
+	.endm
+
 /*
  * reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present
  */
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 753a1c398898..d678f0ceb7ee 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -97,6 +97,8 @@ struct kimage_arch {
 	phys_addr_t dtb_mem;
 	phys_addr_t kern_reloc;
 	phys_addr_t el2_vectors;
+	phys_addr_t ttbr1;
+	phys_addr_t zero_page;
 };
 
 #ifdef CONFIG_KEXEC_FILE
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index ee37d0e0fb6d..f9794cd95eef 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -160,6 +160,8 @@ int main(void)
 #ifdef CONFIG_KEXEC_CORE
   DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));
   DEFINE(KIMAGE_ARCH_EL2_VECTORS,	offsetof(struct kimage, arch.el2_vectors));
+  DEFINE(KIMAGE_ARCH_ZERO_PAGE,		offsetof(struct kimage, arch.zero_page));
+  DEFINE(KIMAGE_ARCH_TTBR1,		offsetof(struct kimage, arch.ttbr1));
   DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));
   DEFINE(KIMAGE_START,			offsetof(struct kimage, start));
   BLANK();
diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
index 8ccca660034e..a31e621ba867 100644
--- a/arch/arm64/kernel/hibernate-asm.S
+++ b/arch/arm64/kernel/hibernate-asm.S
@@ -15,26 +15,6 @@
 #include <asm/page.h>
 #include <asm/virt.h>
 
-/*
- * To prevent the possibility of old and new partial table walks being visible
- * in the tlb, switch the ttbr to a zero page when we invalidate the old
- * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
- * Even switching to our copied tables will cause a changed output address at
- * each stage of the walk.
- */
-.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2
-	phys_to_ttbr \tmp, \zero_page
-	msr	ttbr1_el1, \tmp
-	isb
-	tlbi	vmalle1
-	dsb	nsh
-	phys_to_ttbr \tmp, \page_table
-	offset_ttbr1 \tmp, \tmp2
-	msr	ttbr1_el1, \tmp
-	isb
-.endm
-
-
 /*
  * Resume from hibernate
  *
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 675d27d7aea4..fe0f9c383c17 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -153,6 +153,8 @@ static void *kexec_page_alloc(void *arg)
 
 int machine_kexec_post_load(struct kimage *kimage)
 {
+	int rc;
+	pgd_t *trans_pgd;
 	void *reloc_code = page_to_virt(kimage->control_code_page);
 	long reloc_size;
 	struct trans_pgd_info info = {
@@ -169,12 +171,22 @@ int machine_kexec_post_load(struct kimage *kimage)
 
 	kimage->arch.el2_vectors = 0;
 	if (is_hyp_callable()) {
-		int rc = trans_pgd_copy_el2_vectors(&info,
-						    &kimage->arch.el2_vectors);
+		rc = trans_pgd_copy_el2_vectors(&info,
+						&kimage->arch.el2_vectors);
 		if (rc)
 			return rc;
 	}
 
+	/* Create a copy of the linear map */
+	trans_pgd = kexec_page_alloc(kimage);
+	if (!trans_pgd)
+		return -ENOMEM;
+	rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
+	if (rc)
+		return rc;
+	kimage->arch.ttbr1 = __pa(trans_pgd);
+	kimage->arch.zero_page = __pa(empty_zero_page);
+
 	reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
 	memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 7a600ba33ae1..e83b6380907d 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -29,10 +29,13 @@
  */
 SYM_CODE_START(arm64_relocate_new_kernel)
 	/* Setup the list loop variables. */
+	ldr	x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */
+	ldr	x17, [x0, #KIMAGE_ARCH_TTBR1]	/* x17 = linear map copy */
 	ldr	x16, [x0, #KIMAGE_HEAD]		/* x16 = kimage_head */
 	mov	x14, xzr			/* x14 = entry ptr */
 	mov	x13, xzr			/* x13 = copy dest */
 	raw_dcache_line_size x15, x1		/* x15 = dcache line size */
+	break_before_make_ttbr_switch	x18, x17, x1, x2 /* set linear map */
 .Lloop:
 	and	x12, x16, PAGE_MASK		/* x12 = addr */
 
-- 
2.25.1


_______________________________________________
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] 27+ messages in thread

* [PATCH 15/18] arm64: kexec: keep MMU enabled during kexec relocation
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (13 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 14/18] arm64: kexec: install a copy of the linear-map Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 16/18] arm64: kexec: remove the pre-kexec PoC maintenance Pavel Tatashin
                   ` (2 subsequent siblings)
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Now, that we have linear map page tables configured, keep MMU enabled
to allow faster relocation of segments to final destination.

Cavium ThunderX2:
Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M
MMU-disabled:
relocation	7.489539915s
MMU-enabled:
relocation	0.03946095s

Broadcom Stingray:
The performance data: for a moderate size kernel + initramfs: 25M the
relocation was taking 0.382s, with enabled MMU it now takes
0.019s only or x20 improvement.

The time is proportional to the size of relocation, therefore if initramfs
is larger, 100M it could take over a second.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/kexec.h      |  3 +++
 arch/arm64/kernel/asm-offsets.c     |  1 +
 arch/arm64/kernel/machine_kexec.c   | 16 +++++++++++----
 arch/arm64/kernel/relocate_kernel.S | 31 +++++++++++++++++++----------
 4 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d678f0ceb7ee..dca6dedc3b25 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -97,8 +97,11 @@ struct kimage_arch {
 	phys_addr_t dtb_mem;
 	phys_addr_t kern_reloc;
 	phys_addr_t el2_vectors;
+	phys_addr_t ttbr0;
 	phys_addr_t ttbr1;
 	phys_addr_t zero_page;
+	unsigned long phys_offset;
+	unsigned long t0sz;
 };
 
 #ifdef CONFIG_KEXEC_FILE
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index f9794cd95eef..bbdf20930491 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -161,6 +161,7 @@ int main(void)
   DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));
   DEFINE(KIMAGE_ARCH_EL2_VECTORS,	offsetof(struct kimage, arch.el2_vectors));
   DEFINE(KIMAGE_ARCH_ZERO_PAGE,		offsetof(struct kimage, arch.zero_page));
+  DEFINE(KIMAGE_ARCH_PHYS_OFFSET,	offsetof(struct kimage, arch.phys_offset));
   DEFINE(KIMAGE_ARCH_TTBR1,		offsetof(struct kimage, arch.ttbr1));
   DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));
   DEFINE(KIMAGE_START,			offsetof(struct kimage, start));
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index fe0f9c383c17..96a478d022b6 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -190,6 +190,11 @@ int machine_kexec_post_load(struct kimage *kimage)
 	reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
 	memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
+	rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0,
+				  &kimage->arch.t0sz, reloc_code);
+	if (rc)
+		return rc;
+	kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage;
 
 	/* Flush the reloc_code in preparation for its execution. */
 	__flush_dcache_area(reloc_code, reloc_size);
@@ -223,9 +228,9 @@ void machine_kexec(struct kimage *kimage)
 	local_daif_mask();
 
 	/*
-	 * Both restart and cpu_soft_restart will shutdown the MMU, disable data
+	 * Both restart and kernel_reloc will shutdown the MMU, disable data
 	 * caches. However, restart will start new kernel or purgatory directly,
-	 * cpu_soft_restart will transfer control to arm64_relocate_new_kernel
+	 * kernel_reloc contains the body of arm64_relocate_new_kernel
 	 * In kexec case, kimage->start points to purgatory assuming that
 	 * kernel entry and dtb address are embedded in purgatory by
 	 * userspace (kexec-tools).
@@ -239,10 +244,13 @@ void machine_kexec(struct kimage *kimage)
 		restart(is_hyp_callable(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
+		void (*kernel_reloc)(struct kimage *kimage);
+
 		if (is_hyp_callable())
 			__hyp_set_vectors(kimage->arch.el2_vectors);
-		cpu_soft_restart(kimage->arch.kern_reloc,
-				 virt_to_phys(kimage), 0, 0);
+		cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz);
+		kernel_reloc = (void *)kimage->arch.kern_reloc;
+		kernel_reloc(kimage);
 	}
 
 	BUG(); /* Should never get here. */
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index e83b6380907d..fc2348584a54 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -4,6 +4,8 @@
  *
  * Copyright (C) Linaro.
  * Copyright (C) Huawei Futurewei Technologies.
+ * Copyright (C) 2020, Microsoft Corporation.
+ * Pavel Tatashin <pasha.tatashin@soleen.com>
  */
 
 #include <linux/kexec.h>
@@ -15,6 +17,13 @@
 #include <asm/sysreg.h>
 #include <asm/virt.h>
 
+.macro turn_off_mmu tmp1, tmp2
+	mov_q   \tmp1, INIT_SCTLR_EL1_MMU_OFF
+	pre_disable_mmu_workaround
+	msr	sctlr_el1, \tmp1
+	isb
+.endm
+
 .pushsection    ".kexec_relocate.text", "ax"
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
@@ -32,22 +41,21 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	ldr	x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */
 	ldr	x17, [x0, #KIMAGE_ARCH_TTBR1]	/* x17 = linear map copy */
 	ldr	x16, [x0, #KIMAGE_HEAD]		/* x16 = kimage_head */
-	mov	x14, xzr			/* x14 = entry ptr */
-	mov	x13, xzr			/* x13 = copy dest */
+	ldr	x22, [x0, #KIMAGE_ARCH_PHYS_OFFSET]	/* x22 phys_offset */
 	raw_dcache_line_size x15, x1		/* x15 = dcache line size */
 	break_before_make_ttbr_switch	x18, x17, x1, x2 /* set linear map */
 .Lloop:
 	and	x12, x16, PAGE_MASK		/* x12 = addr */
-
+	sub	x12, x12, x22			/* Convert x12 to virt */
 	/* Test the entry flags. */
 .Ltest_source:
 	tbz	x16, IND_SOURCE_BIT, .Ltest_indirection
 
 	/* Invalidate dest page to PoC. */
-	mov	x2, x13
-	mov	x1, #PAGE_SIZE
-	dcache_by_myline_op ivac, sy, x2, x1, x15, x20
+	mov	x19, x13
 	copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8
+	mov	x1, #PAGE_SIZE
+	dcache_by_myline_op civac, sy, x19, x1, x15, x20
 	b	.Lnext
 .Ltest_indirection:
 	tbz	x16, IND_INDIRECTION_BIT, .Ltest_destination
@@ -64,19 +72,20 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	ic	iallu
 	dsb	nsh
 	isb
+	ldr	x4, [x0, #KIMAGE_START]			/* relocation start */
+	ldr	x1, [x0, #KIMAGE_ARCH_EL2_VECTORS]	/* relocation start */
+	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]		/* dtb address */
+	turn_off_mmu x12, x13
 
 	/* Start new image. */
-	ldr	x1, [x0, #KIMAGE_ARCH_EL2_VECTORS]	/* relocation start */
 	cbz	x1, .Lel1
-	ldr	x1, [x0, #KIMAGE_START]		/* relocation start */
-	ldr	x2, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
+	mov	x1, x4				/* relocation start */
+	mov	x2, x0				/* dtb address */
 	mov	x3, xzr
 	mov	x4, xzr
 	mov     x0, #HVC_SOFT_RESTART
 	hvc	#0				/* Jumps from el2 */
 .Lel1:
-	ldr	x4, [x0, #KIMAGE_START]		/* relocation start */
-	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */
 	mov	x2, xzr
 	mov	x3, xzr
 	br	x4				/* Jumps from el1 */
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 16/18] arm64: kexec: remove the pre-kexec PoC maintenance
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (14 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 15/18] arm64: kexec: keep MMU enabled during kexec relocation Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 17/18] arm64: kexec: Remove cpu-reset.h Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 18/18] arm64/mm: remove useless trans_pgd_map_page() Pavel Tatashin
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

Now that kexec does its relocations with the MMU enabled, we no longer
need to clean the relocation data to the PoC.

Co-developed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/machine_kexec.c | 40 -------------------------------
 1 file changed, 40 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 96a478d022b6..afbde4bb1829 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -76,45 +76,6 @@ int machine_kexec_prepare(struct kimage *kimage)
 	return 0;
 }
 
-/**
- * kexec_list_flush - Helper to flush the kimage list and source pages to PoC.
- */
-static void kexec_list_flush(struct kimage *kimage)
-{
-	kimage_entry_t *entry;
-
-	__flush_dcache_area(kimage, sizeof(*kimage));
-
-	for (entry = &kimage->head; ; entry++) {
-		unsigned int flag;
-		void *addr;
-
-		/* flush the list entries. */
-		__flush_dcache_area(entry, sizeof(kimage_entry_t));
-
-		flag = *entry & IND_FLAGS;
-		if (flag == IND_DONE)
-			break;
-
-		addr = phys_to_virt(*entry & PAGE_MASK);
-
-		switch (flag) {
-		case IND_INDIRECTION:
-			/* Set entry point just before the new list page. */
-			entry = (kimage_entry_t *)addr - 1;
-			break;
-		case IND_SOURCE:
-			/* flush the source pages. */
-			__flush_dcache_area(addr, PAGE_SIZE);
-			break;
-		case IND_DESTINATION:
-			break;
-		default:
-			BUG();
-		}
-	}
-}
-
 /**
  * kexec_segment_flush - Helper to flush the kimage segments to PoC.
  */
@@ -200,7 +161,6 @@ int machine_kexec_post_load(struct kimage *kimage)
 	__flush_dcache_area(reloc_code, reloc_size);
 	flush_icache_range((uintptr_t)reloc_code, (uintptr_t)reloc_code +
 			   reloc_size);
-	kexec_list_flush(kimage);
 	kexec_image_info(kimage);
 
 	return 0;
-- 
2.25.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 17/18] arm64: kexec: Remove cpu-reset.h
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (15 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 16/18] arm64: kexec: remove the pre-kexec PoC maintenance Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  2021-05-27 15:05 ` [PATCH 18/18] arm64/mm: remove useless trans_pgd_map_page() Pavel Tatashin
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

This header contains only cpu_soft_restart() which is never used directly
anymore. So, remove this header, and rename the helper to be
cpu_soft_restart().

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/kexec.h    |  6 ++++++
 arch/arm64/kernel/cpu-reset.S     |  7 +++----
 arch/arm64/kernel/cpu-reset.h     | 30 ------------------------------
 arch/arm64/kernel/machine_kexec.c |  6 ++----
 4 files changed, 11 insertions(+), 38 deletions(-)
 delete mode 100644 arch/arm64/kernel/cpu-reset.h

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index dca6dedc3b25..9839bfc163d7 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -90,6 +90,12 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#if defined(CONFIG_KEXEC_CORE)
+void cpu_soft_restart(unsigned long el2_switch, unsigned long entry,
+		      unsigned long arg0, unsigned long arg1,
+		      unsigned long arg2);
+#endif
+
 #define ARCH_HAS_KIMAGE_ARCH
 
 struct kimage_arch {
diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
index d47ff63a5b66..48a8af97faa9 100644
--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -16,8 +16,7 @@
 .pushsection    .idmap.text, "awx"
 
 /*
- * __cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2) - Helper for
- * cpu_soft_restart.
+ * cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2)
  *
  * @el2_switch: Flag to indicate a switch to EL2 is needed.
  * @entry: Location to jump to for soft reset.
@@ -29,7 +28,7 @@
  * branch to what would be the reset vector. It must be executed with the
  * flat identity mapping.
  */
-SYM_CODE_START(__cpu_soft_restart)
+SYM_CODE_START(cpu_soft_restart)
 	mov_q	x12, INIT_SCTLR_EL1_MMU_OFF
 	pre_disable_mmu_workaround
 	/*
@@ -48,6 +47,6 @@ SYM_CODE_START(__cpu_soft_restart)
 	mov	x1, x3				// arg1
 	mov	x2, x4				// arg2
 	br	x8
-SYM_CODE_END(__cpu_soft_restart)
+SYM_CODE_END(cpu_soft_restart)
 
 .popsection
diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
deleted file mode 100644
index 296abbac7192..000000000000
--- a/arch/arm64/kernel/cpu-reset.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * CPU reset routines
- *
- * Copyright (C) 2015 Huawei Futurewei Technologies.
- */
-
-#ifndef _ARM64_CPU_RESET_H
-#define _ARM64_CPU_RESET_H
-
-#include <asm/virt.h>
-
-void __cpu_soft_restart(unsigned long el2_switch, unsigned long entry,
-	unsigned long arg0, unsigned long arg1, unsigned long arg2);
-
-static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry,
-						       unsigned long arg0,
-						       unsigned long arg1,
-						       unsigned long arg2)
-{
-	typeof(__cpu_soft_restart) *restart;
-
-	restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
-
-	cpu_install_idmap();
-	restart(0, entry, arg0, arg1, arg2);
-	unreachable();
-}
-
-#endif
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index afbde4bb1829..16996b568fd3 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -23,8 +23,6 @@
 #include <asm/sections.h>
 #include <asm/trans_pgd.h>
 
-#include "cpu-reset.h"
-
 /**
  * kexec_image_info - For debugging output.
  */
@@ -197,10 +195,10 @@ void machine_kexec(struct kimage *kimage)
 	 * In kexec_file case, the kernel starts directly without purgatory.
 	 */
 	if (kimage->head & IND_DONE) {
-		typeof(__cpu_soft_restart) *restart;
+		typeof(cpu_soft_restart) *restart;
 
 		cpu_install_idmap();
-		restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
+		restart = (void *)__pa_symbol(function_nocfi(cpu_soft_restart));
 		restart(is_hyp_callable(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* [PATCH 18/18] arm64/mm: remove useless trans_pgd_map_page()
  2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
                   ` (16 preceding siblings ...)
  2021-05-27 15:05 ` [PATCH 17/18] arm64: kexec: Remove cpu-reset.h Pavel Tatashin
@ 2021-05-27 15:05 ` Pavel Tatashin
  17 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 15:05 UTC (permalink / raw)
  To: pasha.tatashin, jmorris, sashal, ebiederm, kexec, linux-kernel,
	corbet, catalin.marinas, will, linux-arm-kernel, maz,
	james.morse, vladimir.murzin, matthias.bgg, linux-mm,
	mark.rutland, steve.capper, rfontana, tglx, selindag, tyhicks,
	kernelfans, akpm, madvenka

From: Pingfan Liu <kernelfans@gmail.com>

The intend of trans_pgd_map_page() was to map contigous range of VA
memory to the memory that is getting relocated during kexec. However,
since we are now using linear map instead of contigous range this
function is not needed

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
[Changed commit message]
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/trans_pgd.h |  5 +--
 arch/arm64/mm/trans_pgd.c          | 57 ------------------------------
 2 files changed, 1 insertion(+), 61 deletions(-)

diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
index e0760e52d36d..234353df2f13 100644
--- a/arch/arm64/include/asm/trans_pgd.h
+++ b/arch/arm64/include/asm/trans_pgd.h
@@ -15,7 +15,7 @@
 /*
  * trans_alloc_page
  *	- Allocator that should return exactly one zeroed page, if this
- *	  allocator fails, trans_pgd_create_copy() and trans_pgd_map_page()
+ *	  allocator fails, trans_pgd_create_copy() and trans_pgd_idmap_page()
  *	  return -ENOMEM error.
  *
  * trans_alloc_arg
@@ -30,9 +30,6 @@ struct trans_pgd_info {
 int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd,
 			  unsigned long start, unsigned long end);
 
-int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
-		       void *page, unsigned long dst_addr, pgprot_t pgprot);
-
 int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 			 unsigned long *t0sz, void *page);
 
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 61549451ed3a..e24a749013c1 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -217,63 +217,6 @@ int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **dst_pgdp,
 	return rc;
 }
 
-/*
- * Add map entry to trans_pgd for a base-size page at PTE level.
- * info:	contains allocator and its argument
- * trans_pgd:	page table in which new map is added.
- * page:	page to be mapped.
- * dst_addr:	new VA address for the page
- * pgprot:	protection for the page.
- *
- * Returns 0 on success, and -ENOMEM on failure.
- */
-int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
-		       void *page, unsigned long dst_addr, pgprot_t pgprot)
-{
-	pgd_t *pgdp;
-	p4d_t *p4dp;
-	pud_t *pudp;
-	pmd_t *pmdp;
-	pte_t *ptep;
-
-	pgdp = pgd_offset_pgd(trans_pgd, dst_addr);
-	if (pgd_none(READ_ONCE(*pgdp))) {
-		p4dp = trans_alloc(info);
-		if (!pgdp)
-			return -ENOMEM;
-		pgd_populate(NULL, pgdp, p4dp);
-	}
-
-	p4dp = p4d_offset(pgdp, dst_addr);
-	if (p4d_none(READ_ONCE(*p4dp))) {
-		pudp = trans_alloc(info);
-		if (!pudp)
-			return -ENOMEM;
-		p4d_populate(NULL, p4dp, pudp);
-	}
-
-	pudp = pud_offset(p4dp, dst_addr);
-	if (pud_none(READ_ONCE(*pudp))) {
-		pmdp = trans_alloc(info);
-		if (!pmdp)
-			return -ENOMEM;
-		pud_populate(NULL, pudp, pmdp);
-	}
-
-	pmdp = pmd_offset(pudp, dst_addr);
-	if (pmd_none(READ_ONCE(*pmdp))) {
-		ptep = trans_alloc(info);
-		if (!ptep)
-			return -ENOMEM;
-		pmd_populate_kernel(NULL, pmdp, ptep);
-	}
-
-	ptep = pte_offset_kernel(pmdp, dst_addr);
-	set_pte(ptep, pfn_pte(virt_to_pfn(page), pgprot));
-
-	return 0;
-}
-
 /*
  * The page we want to idmap may be outside the range covered by VA_BITS that
  * can be built using the kernel's p?d_populate() helpers. As a one off, for a
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 27+ messages in thread

* Re: [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-05-27 15:05 ` [PATCH 03/18] arm64: hyp-stub: Move elx_sync " Pavel Tatashin
@ 2021-05-27 15:54   ` Marc Zyngier
  2021-05-27 21:23     ` Pavel Tatashin
  0 siblings, 1 reply; 27+ messages in thread
From: Marc Zyngier @ 2021-05-27 15:54 UTC (permalink / raw)
  To: Pavel Tatashin
  Cc: jmorris, sashal, ebiederm, kexec, linux-kernel, corbet,
	catalin.marinas, will, linux-arm-kernel, james.morse,
	vladimir.murzin, matthias.bgg, linux-mm, mark.rutland,
	steve.capper, rfontana, tglx, selindag, tyhicks, kernelfans,
	akpm, madvenka

On Thu, 27 May 2021 16:05:11 +0100,
Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> 
> The hyp-stub's elx_sync code fits in the vector.
> 
> With this, all of the hyp-stubs behaviour is contained in its vectors.
> This lets kexec and hibernate copy the hyp-stub when they need its
> behaviour, instead of re-implementing it.
> 
> Co-developed-by: James Morse <james.morse@arm.com>
> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> ---
>  arch/arm64/kernel/hyp-stub.S | 64 +++++++++++++++++++-----------------
>  1 file changed, 33 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index 18a97bee3779..86af6c4e52b9 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -21,6 +21,37 @@ SYM_CODE_START_LOCAL(\label)
>  	.align 7
>  	b	\label
>  SYM_CODE_END(\label)
> +.endm
> +
> +.macro elx_sync_vector	label
> +SYM_CODE_START_LOCAL(\label)
> +	.align 7
> +	cmp	x0, #HVC_SET_VECTORS
> +	b.ne	1f
> +	msr	vbar_el2, x1
> +	b	9f
> +
> +1:	cmp	x0, #HVC_VHE_RESTART
> +	b.eq	mutate_to_vhe

Now that this has turned into a macro, what are the guarantees that
mutate_to_vhe will be within reach of the site where this macro is
expanded? It does work here, but what about the other expansion sites
that will show up later in the series?

What was wrong with directly branching to the original call site?
Nothing in the commit message explains it.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-05-27 15:54   ` Marc Zyngier
@ 2021-05-27 21:23     ` Pavel Tatashin
  2021-06-01 12:22       ` Marc Zyngier
  0 siblings, 1 reply; 27+ messages in thread
From: Pavel Tatashin @ 2021-05-27 21:23 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

On Thu, May 27, 2021 at 11:54 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Thu, 27 May 2021 16:05:11 +0100,
> Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> >
> > The hyp-stub's elx_sync code fits in the vector.
> >
> > With this, all of the hyp-stubs behaviour is contained in its vectors.
> > This lets kexec and hibernate copy the hyp-stub when they need its
> > behaviour, instead of re-implementing it.
> >
> > Co-developed-by: James Morse <james.morse@arm.com>
> > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> > ---
> >  arch/arm64/kernel/hyp-stub.S | 64 +++++++++++++++++++-----------------
> >  1 file changed, 33 insertions(+), 31 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> > index 18a97bee3779..86af6c4e52b9 100644
> > --- a/arch/arm64/kernel/hyp-stub.S
> > +++ b/arch/arm64/kernel/hyp-stub.S
> > @@ -21,6 +21,37 @@ SYM_CODE_START_LOCAL(\label)
> >       .align 7
> >       b       \label
> >  SYM_CODE_END(\label)
> > +.endm
> > +
> > +.macro elx_sync_vector       label
> > +SYM_CODE_START_LOCAL(\label)
> > +     .align 7
> > +     cmp     x0, #HVC_SET_VECTORS
> > +     b.ne    1f
> > +     msr     vbar_el2, x1
> > +     b       9f
> > +
> > +1:   cmp     x0, #HVC_VHE_RESTART
> > +     b.eq    mutate_to_vhe
>
> Now that this has turned into a macro, what are the guarantees that
> mutate_to_vhe will be within reach of the site where this macro is
> expanded? It does work here, but what about the other expansion sites
> that will show up later in the series?
>
> What was wrong with directly branching to the original call site?
> Nothing in the commit message explains it.

Hi Marc,

I need to explain this better in the commit log. Later in the series
we create our own vector copy that is outside of the old and new
kernel so it does not get overwritten during kexec relocation. When
VHE is enabled, the vector is passed so we can switch to el2 before
jumping to the new kernel.

arm64_relocate_new_kernel() which performs the relocation runs with
MMU being enabled until relocation is done, after that disables MMU
and if vectors are passed performs:

         mov     x0, #HVC_SOFT_RESTART
         hvc     #0         /* Jumps from el2 */

It cannot call mutate_to_vhe because #HVC_VHE_RESTART is not used
here. But, if it had to it would not work as we cannot return to the
old kernel text after relocation.

Thanks,
Pasha

>
> Thanks,
>
>         M.
>
> --
> Without deviation from the norm, progress is not possible.

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-05-27 21:23     ` Pavel Tatashin
@ 2021-06-01 12:22       ` Marc Zyngier
  2021-06-02  1:18         ` Pavel Tatashin
  0 siblings, 1 reply; 27+ messages in thread
From: Marc Zyngier @ 2021-06-01 12:22 UTC (permalink / raw)
  To: Pavel Tatashin
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

On Thu, 27 May 2021 22:23:22 +0100,
Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> 
> On Thu, May 27, 2021 at 11:54 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Thu, 27 May 2021 16:05:11 +0100,
> > Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> > >
> > > The hyp-stub's elx_sync code fits in the vector.
> > >
> > > With this, all of the hyp-stubs behaviour is contained in its vectors.
> > > This lets kexec and hibernate copy the hyp-stub when they need its
> > > behaviour, instead of re-implementing it.
> > >
> > > Co-developed-by: James Morse <james.morse@arm.com>
> > > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> > > ---
> > >  arch/arm64/kernel/hyp-stub.S | 64 +++++++++++++++++++-----------------
> > >  1 file changed, 33 insertions(+), 31 deletions(-)
> > >
> > > diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> > > index 18a97bee3779..86af6c4e52b9 100644
> > > --- a/arch/arm64/kernel/hyp-stub.S
> > > +++ b/arch/arm64/kernel/hyp-stub.S
> > > @@ -21,6 +21,37 @@ SYM_CODE_START_LOCAL(\label)
> > >       .align 7
> > >       b       \label
> > >  SYM_CODE_END(\label)
> > > +.endm
> > > +
> > > +.macro elx_sync_vector       label
> > > +SYM_CODE_START_LOCAL(\label)
> > > +     .align 7
> > > +     cmp     x0, #HVC_SET_VECTORS
> > > +     b.ne    1f
> > > +     msr     vbar_el2, x1
> > > +     b       9f
> > > +
> > > +1:   cmp     x0, #HVC_VHE_RESTART
> > > +     b.eq    mutate_to_vhe
> >
> > Now that this has turned into a macro, what are the guarantees that
> > mutate_to_vhe will be within reach of the site where this macro is
> > expanded? It does work here, but what about the other expansion sites
> > that will show up later in the series?
> >
> > What was wrong with directly branching to the original call site?
> > Nothing in the commit message explains it.
> 
> Hi Marc,
> 
> I need to explain this better in the commit log. Later in the series
> we create our own vector copy that is outside of the old and new
> kernel so it does not get overwritten during kexec relocation. When
> VHE is enabled, the vector is passed so we can switch to el2 before
> jumping to the new kernel.
> 
> arm64_relocate_new_kernel() which performs the relocation runs with
> MMU being enabled until relocation is done, after that disables MMU
> and if vectors are passed performs:
> 
>          mov     x0, #HVC_SOFT_RESTART
>          hvc     #0         /* Jumps from el2 */
> 
> It cannot call mutate_to_vhe because #HVC_VHE_RESTART is not used
> here. But, if it had to it would not work as we cannot return to the
> old kernel text after relocation.

OK, so you are happy with having a dangling branch pointing to
nowhere? Something in me screams that it isn't a good idea, in
general.

If HVC_SOFT_RESTART is all you need, I'd rather you have a small stub
that implements exactly that and nothing else. Feel free to extract it
as a reusable macro if you want.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE
  2021-05-27 15:05 ` [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE Pavel Tatashin
@ 2021-06-01 12:38   ` Marc Zyngier
  2021-06-02  1:33     ` Pavel Tatashin
  0 siblings, 1 reply; 27+ messages in thread
From: Marc Zyngier @ 2021-06-01 12:38 UTC (permalink / raw)
  To: Pavel Tatashin
  Cc: jmorris, sashal, ebiederm, kexec, linux-kernel, corbet,
	catalin.marinas, will, linux-arm-kernel, james.morse,
	vladimir.murzin, matthias.bgg, linux-mm, mark.rutland,
	steve.capper, rfontana, tglx, selindag, tyhicks, kernelfans,
	akpm, madvenka

On Thu, 27 May 2021 16:05:12 +0100,
Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> 
> Replace places that contain logic like this:
> 	is_hyp_mode_available() && !is_kernel_in_hyp_mode()
> 
> With a dedicated boolean function  is_hyp_callable(). This will be needed
> later in kexec in order to sooner switch back to EL2.

This looks like the very definition of "run in nVHE mode", so I'd
rather you call it like this, rather than "callable", which is
extremely ambiguous (if running at EL2, I call it any time I want, for
free).

> 
> Suggested-by: James Morse <james.morse@arm.com>
> 
> [Fixed merging issues]
> 
> Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> ---
>  arch/arm64/include/asm/virt.h | 5 +++++
>  arch/arm64/kernel/cpu-reset.h | 3 +--
>  arch/arm64/kernel/hibernate.c | 9 +++------
>  arch/arm64/kernel/sdei.c      | 2 +-
>  4 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> index 7379f35ae2c6..4216c8623538 100644
> --- a/arch/arm64/include/asm/virt.h
> +++ b/arch/arm64/include/asm/virt.h
> @@ -128,6 +128,11 @@ static __always_inline bool is_protected_kvm_enabled(void)
>  		return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
>  }
>  
> +static inline bool is_hyp_callable(void)
> +{
> +	return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
> +}

nit: consider switching the two members of the expression so that you
don't have extra memory accesses when running at EL2.

> +
>  #endif /* __ASSEMBLY__ */
>  
>  #endif /* ! __ASM__VIRT_H */
> diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
> index 9a7b1262ef17..48d0ed48c147 100644
> --- a/arch/arm64/kernel/cpu-reset.h
> +++ b/arch/arm64/kernel/cpu-reset.h
> @@ -20,8 +20,7 @@ static inline void __noreturn __nocfi cpu_soft_restart(unsigned long entry,
>  {
>  	typeof(__cpu_soft_restart) *restart;
>  
> -	unsigned long el2_switch = !is_kernel_in_hyp_mode() &&
> -		is_hyp_mode_available();
> +	unsigned long el2_switch = is_hyp_callable();
>  	restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart));
>  
>  	cpu_install_idmap();
> diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> index b1cef371df2b..c764574a1acb 100644
> --- a/arch/arm64/kernel/hibernate.c
> +++ b/arch/arm64/kernel/hibernate.c
> @@ -48,9 +48,6 @@
>   */
>  extern int in_suspend;
>  
> -/* Do we need to reset el2? */
> -#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
> -

Please keep the macro, as it explains *why* we're doing things (we
need to reset EL2), and replacing it with a generic macro drops the
documentation aspect.

>  /* temporary el2 vectors in the __hibernate_exit_text section. */
>  extern char hibernate_el2_vectors[];
>  
> @@ -125,7 +122,7 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
>  	hdr->reenter_kernel	= _cpu_resume;
>  
>  	/* We can't use __hyp_get_vectors() because kvm may still be loaded */
> -	if (el2_reset_needed())
> +	if (is_hyp_callable())
>  		hdr->__hyp_stub_vectors = __pa_symbol(__hyp_stub_vectors);
>  	else
>  		hdr->__hyp_stub_vectors = 0;
> @@ -387,7 +384,7 @@ int swsusp_arch_suspend(void)
>  		dcache_clean_range(__idmap_text_start, __idmap_text_end);
>  
>  		/* Clean kvm setup code to PoC? */
> -		if (el2_reset_needed()) {
> +		if (is_hyp_callable()) {
>  			dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end);
>  			dcache_clean_range(__hyp_text_start, __hyp_text_end);
>  		}
> @@ -482,7 +479,7 @@ int swsusp_arch_resume(void)
>  	 *
>  	 * We can skip this step if we booted at EL1, or are running with VHE.
>  	 */
> -	if (el2_reset_needed()) {
> +	if (is_hyp_callable()) {
>  		phys_addr_t el2_vectors = (phys_addr_t)hibernate_exit;
>  		el2_vectors += hibernate_el2_vectors -
>  			       __hibernate_exit_text_start;     /* offset */
> diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
> index 2c7ca449dd51..af0ac2f920cf 100644
> --- a/arch/arm64/kernel/sdei.c
> +++ b/arch/arm64/kernel/sdei.c
> @@ -200,7 +200,7 @@ unsigned long sdei_arch_get_entry_point(int conduit)
>  	 * dropped to EL1 because we don't support VHE, then we can't support
>  	 * SDEI.
>  	 */
> -	if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
> +	if (is_hyp_callable()) {
>  		pr_err("Not supported on this hardware/boot configuration\n");
>  		goto out_err;
>  	}
> -- 
> 2.25.1
> 
> 

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-06-01 12:22       ` Marc Zyngier
@ 2021-06-02  1:18         ` Pavel Tatashin
  2021-06-08 17:46           ` Pavel Tatashin
  0 siblings, 1 reply; 27+ messages in thread
From: Pavel Tatashin @ 2021-06-02  1:18 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

> > It cannot call mutate_to_vhe because #HVC_VHE_RESTART is not used
> > here. But, if it had to it would not work as we cannot return to the
> > old kernel text after relocation.
>
> OK, so you are happy with having a dangling branch pointing to
> nowhere? Something in me screams that it isn't a good idea, in
> general.
>
> If HVC_SOFT_RESTART is all you need, I'd rather you have a small stub
> that implements exactly that and nothing else. Feel free to extract it
> as a reusable macro if you want.

Sure, I will add in the next revision.

Thanks,
Pasha

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE
  2021-06-01 12:38   ` Marc Zyngier
@ 2021-06-02  1:33     ` Pavel Tatashin
  2021-06-02  8:20       ` Marc Zyngier
  0 siblings, 1 reply; 27+ messages in thread
From: Pavel Tatashin @ 2021-06-02  1:33 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

On Tue, Jun 1, 2021 at 8:38 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Thu, 27 May 2021 16:05:12 +0100,
> Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> >
> > Replace places that contain logic like this:
> >       is_hyp_mode_available() && !is_kernel_in_hyp_mode()
> >
> > With a dedicated boolean function  is_hyp_callable(). This will be needed
> > later in kexec in order to sooner switch back to EL2.
>
> This looks like the very definition of "run in nVHE mode", so I'd
> rather you call it like this, rather than "callable", which is
> extremely ambiguous (if running at EL2, I call it any time I want, for
> free).

Hi Marc,

Naming is hard. Are you proposing  s/is_hyp_callable/run_in_nvhe_mode/
? This is also not a very good name because it does not sound like a
boolean, but instead that we know that there is nvhe mode available
and we can switch to it.

>
> >
> > Suggested-by: James Morse <james.morse@arm.com>
> >
> > [Fixed merging issues]
> >
> > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> > ---
> >  arch/arm64/include/asm/virt.h | 5 +++++
> >  arch/arm64/kernel/cpu-reset.h | 3 +--
> >  arch/arm64/kernel/hibernate.c | 9 +++------
> >  arch/arm64/kernel/sdei.c      | 2 +-
> >  4 files changed, 10 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> > index 7379f35ae2c6..4216c8623538 100644
> > --- a/arch/arm64/include/asm/virt.h
> > +++ b/arch/arm64/include/asm/virt.h
> > @@ -128,6 +128,11 @@ static __always_inline bool is_protected_kvm_enabled(void)
> >               return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
> >  }
> >
> > +static inline bool is_hyp_callable(void)
> > +{
> > +     return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
> > +}
>
> nit: consider switching the two members of the expression so that you
> don't have extra memory accesses when running at EL2.

Sure, I will do that.


> > -/* Do we need to reset el2? */
> > -#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
> > -
>
> Please keep the macro, as it explains *why* we're doing things (we
> need to reset EL2), and replacing it with a generic macro drops the
> documentation aspect.

OK, I will keep the macro, and redefine it to use the common macro.

Thank you,
Pasha

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE
  2021-06-02  1:33     ` Pavel Tatashin
@ 2021-06-02  8:20       ` Marc Zyngier
  0 siblings, 0 replies; 27+ messages in thread
From: Marc Zyngier @ 2021-06-02  8:20 UTC (permalink / raw)
  To: Pavel Tatashin
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

On Wed, 02 Jun 2021 02:33:52 +0100,
Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> 
> On Tue, Jun 1, 2021 at 8:38 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Thu, 27 May 2021 16:05:12 +0100,
> > Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
> > >
> > > Replace places that contain logic like this:
> > >       is_hyp_mode_available() && !is_kernel_in_hyp_mode()
> > >
> > > With a dedicated boolean function  is_hyp_callable(). This will be needed
> > > later in kexec in order to sooner switch back to EL2.
> >
> > This looks like the very definition of "run in nVHE mode", so I'd
> > rather you call it like this, rather than "callable", which is
> > extremely ambiguous (if running at EL2, I call it any time I want, for
> > free).
> 
> Hi Marc,
> 
> Naming is hard.

News flash!

> Are you proposing s/is_hyp_callable/run_in_nvhe_mode/ ? This is also
> not a very good name because it does not sound like a boolean, but
> instead that we know that there is nvhe mode available and we can
> switch to it.

No, what I suggest is "is_hyp_nvhe()", or something along those
lines. It clearly identifies that we are in control of EL2, and which
mode it is in.

	M.

-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
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] 27+ messages in thread

* Re: [PATCH 03/18] arm64: hyp-stub: Move elx_sync into the vectors
  2021-06-02  1:18         ` Pavel Tatashin
@ 2021-06-08 17:46           ` Pavel Tatashin
  0 siblings, 0 replies; 27+ messages in thread
From: Pavel Tatashin @ 2021-06-08 17:46 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: James Morris, Sasha Levin, Eric W. Biederman, kexec mailing list,
	LKML, Jonathan Corbet, Catalin Marinas, Will Deacon, Linux ARM,
	James Morse, Vladimir Murzin, Matthias Brugger, linux-mm,
	Mark Rutland, steve.capper, rfontana, Thomas Gleixner, Selin Dag,
	Tyler Hicks, Pingfan Liu, Andrew Morton, madvenka

On Tue, Jun 1, 2021 at 9:18 PM Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
>
> > > It cannot call mutate_to_vhe because #HVC_VHE_RESTART is not used
> > > here. But, if it had to it would not work as we cannot return to the
> > > old kernel text after relocation.
> >
> > OK, so you are happy with having a dangling branch pointing to
> > nowhere? Something in me screams that it isn't a good idea, in
> > general.
> >
> > If HVC_SOFT_RESTART is all you need, I'd rather you have a small stub
> > that implements exactly that and nothing else. Feel free to extract it
> > as a reusable macro if you want.

Using macro won't help here to save kernel text. Optimally, we would
want to use only one vector table to reduce kernel text memory usage.
I could do that by overwriting sync entries in
trans_pgd_copy_el2_vectors(). But, that would be ugly, as I would need
to have some specific assumptions about what entries need to be
overwritten. Therefore, I decided to move the vector table that we
currently have in hibernate code, and make it common between kexec and
hibernate; trans_pgd_copy_el2_vectors() will use that table's body to
create copies.

Thanks,
Pasha

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^ permalink raw reply	[flat|nested] 27+ messages in thread

end of thread, other threads:[~2021-06-08 17:48 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-27 15:05 [PATCH 00/18] arm64: MMU enabled kexec relocation Pavel Tatashin
2021-05-27 15:05 ` [PATCH 01/18] arm64: hyp-stub: Check the size of the HYP stub's vectors Pavel Tatashin
2021-05-27 15:05 ` [PATCH 02/18] arm64: hyp-stub: Move invalid vector entries into the vectors Pavel Tatashin
2021-05-27 15:05 ` [PATCH 03/18] arm64: hyp-stub: Move elx_sync " Pavel Tatashin
2021-05-27 15:54   ` Marc Zyngier
2021-05-27 21:23     ` Pavel Tatashin
2021-06-01 12:22       ` Marc Zyngier
2021-06-02  1:18         ` Pavel Tatashin
2021-06-08 17:46           ` Pavel Tatashin
2021-05-27 15:05 ` [PATCH 04/18] arm64: kernel: add helper for booted at EL2 and not VHE Pavel Tatashin
2021-06-01 12:38   ` Marc Zyngier
2021-06-02  1:33     ` Pavel Tatashin
2021-06-02  8:20       ` Marc Zyngier
2021-05-27 15:05 ` [PATCH 05/18] arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors Pavel Tatashin
2021-05-27 15:05 ` [PATCH 06/18] arm64: hibernate: abstract ttrb0 setup function Pavel Tatashin
2021-05-27 15:05 ` [PATCH 07/18] arm64: kexec: flush image and lists during kexec load time Pavel Tatashin
2021-05-27 15:05 ` [PATCH 08/18] arm64: kexec: skip relocation code for inplace kexec Pavel Tatashin
2021-05-27 15:05 ` [PATCH 09/18] arm64: kexec: Use dcache ops macros instead of open-coding Pavel Tatashin
2021-05-27 15:05 ` [PATCH 10/18] arm64: kexec: pass kimage as the only argument to relocation function Pavel Tatashin
2021-05-27 15:05 ` [PATCH 11/18] arm64: kexec: kexec may require EL2 vectors Pavel Tatashin
2021-05-27 15:05 ` [PATCH 12/18] arm64: kexec: relocate in EL1 mode Pavel Tatashin
2021-05-27 15:05 ` [PATCH 13/18] arm64: kexec: use ld script for relocation function Pavel Tatashin
2021-05-27 15:05 ` [PATCH 14/18] arm64: kexec: install a copy of the linear-map Pavel Tatashin
2021-05-27 15:05 ` [PATCH 15/18] arm64: kexec: keep MMU enabled during kexec relocation Pavel Tatashin
2021-05-27 15:05 ` [PATCH 16/18] arm64: kexec: remove the pre-kexec PoC maintenance Pavel Tatashin
2021-05-27 15:05 ` [PATCH 17/18] arm64: kexec: Remove cpu-reset.h Pavel Tatashin
2021-05-27 15:05 ` [PATCH 18/18] arm64/mm: remove useless trans_pgd_map_page() Pavel Tatashin

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