* [patch v2 0/2] kdump: Allow removal of page tables for crashkernel memory
@ 2011-09-13 13:26 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390
Hello Vivek, Andrew, Martin
Here the updated patch series for the removal of page tables for the
crashkernel memory:
[1] kdump: Add infrastructure for unmapping crashkernel memory
[2] s390: Add architecture code for unmapping crashkernel memory
The patches apply on top of the last kdump patch series that I sent.
I would suggest that Martin sends the patches together with the other s390
kdump patches in the next merge window.
Andrew is that ok for you?
Michael
^ permalink raw reply [flat|nested] 16+ messages in thread
* [patch v2 0/2] kdump: Allow removal of page tables for crashkernel memory
@ 2011-09-13 13:26 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, kexec
Hello Vivek, Andrew, Martin
Here the updated patch series for the removal of page tables for the
crashkernel memory:
[1] kdump: Add infrastructure for unmapping crashkernel memory
[2] s390: Add architecture code for unmapping crashkernel memory
The patches apply on top of the last kdump patch series that I sent.
I would suggest that Martin sends the patches together with the other s390
kdump patches in the next merge window.
Andrew is that ok for you?
Michael
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* [patch v2 1/2] kdump: Add infrastructure for unmapping crashkernel memory
2011-09-13 13:26 ` Michael Holzheu
@ 2011-09-13 13:26 ` Michael Holzheu
-1 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390
[-- Attachment #1: s390-kdump-common-crash_map_pages.patch --]
[-- Type: text/plain, Size: 3427 bytes --]
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
This patch introduces a mechanism that allows architecture backends to
remove page tables for the crashkernel memory. This can protect the loaded
kdump kernel from being overwritten by broken kernel code. Two new
functions crash_map_reserved_pages() and crash_unmap_reserved_pages() are
added that can be implemented by architecture code. The
crash_map_reserved_pages() function is called before and
crash_unmap_reserved_pages() after the crashkernel segments are loaded. The
functions are also called in crash_shrink_memory() to create/remove page
tables when the crashkernel memory size is reduced.
To support architectures that have large pages this patch also introduces
a new define KEXEC_CRASH_MEM_ALIGN. The crashkernel start and size must
always be aligned with KEXEC_CRASH_MEM_ALIGN.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
include/linux/kexec.h | 6 ++++++
kernel/kexec.c | 21 +++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -37,6 +37,10 @@
#define KEXEC_CRASH_CONTROL_MEMORY_LIMIT KEXEC_CONTROL_MEMORY_LIMIT
#endif
+#ifndef KEXEC_CRASH_MEM_ALIGN
+#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
+#endif
+
#define KEXEC_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
#define KEXEC_CORE_NOTE_NAME "CORE"
#define KEXEC_CORE_NOTE_NAME_BYTES ALIGN(sizeof(KEXEC_CORE_NOTE_NAME), 4)
@@ -133,6 +137,8 @@ extern void crash_kexec(struct pt_regs *
int kexec_should_crash(struct task_struct *);
void crash_save_cpu(struct pt_regs *regs, int cpu);
void crash_save_vmcoreinfo(void);
+void crash_map_reserved_pages(void);
+void crash_unmap_reserved_pages(void);
void arch_crash_save_vmcoreinfo(void);
void vmcoreinfo_append_str(const char *fmt, ...)
__attribute__ ((format (printf, 1, 2)));
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -999,6 +999,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
kimage_free(xchg(&kexec_crash_image, NULL));
result = kimage_crash_alloc(&image, entry,
nr_segments, segments);
+ crash_map_reserved_pages();
}
if (result)
goto out;
@@ -1015,6 +1016,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
goto out;
}
kimage_terminate(image);
+ if (flags & KEXEC_ON_CRASH)
+ crash_unmap_reserved_pages();
}
/* Install the new kernel, and Uninstall the old */
image = xchg(dest_image, image);
@@ -1026,6 +1029,18 @@ out:
return result;
}
+/*
+ * Add and remove page tables for crashkernel memory
+ *
+ * Provide an empty default implementation here -- architecture
+ * code may override this
+ */
+void __weak crash_map_reserved_pages(void)
+{}
+
+void __weak crash_unmap_reserved_pages(void)
+{}
+
#ifdef CONFIG_COMPAT
asmlinkage long compat_sys_kexec_load(unsigned long entry,
unsigned long nr_segments,
@@ -1134,14 +1149,16 @@ int crash_shrink_memory(unsigned long ne
goto unlock;
}
- start = roundup(start, PAGE_SIZE);
- end = roundup(start + new_size, PAGE_SIZE);
+ start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
+ end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
+ crash_map_reserved_pages();
crash_free_reserved_phys_range(end, crashk_res.end);
if ((start == end) && (crashk_res.parent != NULL))
release_resource(&crashk_res);
crashk_res.end = end - 1;
+ crash_unmap_reserved_pages();
unlock:
mutex_unlock(&kexec_mutex);
^ permalink raw reply [flat|nested] 16+ messages in thread
* [patch v2 1/2] kdump: Add infrastructure for unmapping crashkernel memory
@ 2011-09-13 13:26 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, kexec
[-- Attachment #1: s390-kdump-common-crash_map_pages.patch --]
[-- Type: text/plain, Size: 3571 bytes --]
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
This patch introduces a mechanism that allows architecture backends to
remove page tables for the crashkernel memory. This can protect the loaded
kdump kernel from being overwritten by broken kernel code. Two new
functions crash_map_reserved_pages() and crash_unmap_reserved_pages() are
added that can be implemented by architecture code. The
crash_map_reserved_pages() function is called before and
crash_unmap_reserved_pages() after the crashkernel segments are loaded. The
functions are also called in crash_shrink_memory() to create/remove page
tables when the crashkernel memory size is reduced.
To support architectures that have large pages this patch also introduces
a new define KEXEC_CRASH_MEM_ALIGN. The crashkernel start and size must
always be aligned with KEXEC_CRASH_MEM_ALIGN.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
include/linux/kexec.h | 6 ++++++
kernel/kexec.c | 21 +++++++++++++++++++--
2 files changed, 25 insertions(+), 2 deletions(-)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -37,6 +37,10 @@
#define KEXEC_CRASH_CONTROL_MEMORY_LIMIT KEXEC_CONTROL_MEMORY_LIMIT
#endif
+#ifndef KEXEC_CRASH_MEM_ALIGN
+#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
+#endif
+
#define KEXEC_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
#define KEXEC_CORE_NOTE_NAME "CORE"
#define KEXEC_CORE_NOTE_NAME_BYTES ALIGN(sizeof(KEXEC_CORE_NOTE_NAME), 4)
@@ -133,6 +137,8 @@ extern void crash_kexec(struct pt_regs *
int kexec_should_crash(struct task_struct *);
void crash_save_cpu(struct pt_regs *regs, int cpu);
void crash_save_vmcoreinfo(void);
+void crash_map_reserved_pages(void);
+void crash_unmap_reserved_pages(void);
void arch_crash_save_vmcoreinfo(void);
void vmcoreinfo_append_str(const char *fmt, ...)
__attribute__ ((format (printf, 1, 2)));
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -999,6 +999,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
kimage_free(xchg(&kexec_crash_image, NULL));
result = kimage_crash_alloc(&image, entry,
nr_segments, segments);
+ crash_map_reserved_pages();
}
if (result)
goto out;
@@ -1015,6 +1016,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
goto out;
}
kimage_terminate(image);
+ if (flags & KEXEC_ON_CRASH)
+ crash_unmap_reserved_pages();
}
/* Install the new kernel, and Uninstall the old */
image = xchg(dest_image, image);
@@ -1026,6 +1029,18 @@ out:
return result;
}
+/*
+ * Add and remove page tables for crashkernel memory
+ *
+ * Provide an empty default implementation here -- architecture
+ * code may override this
+ */
+void __weak crash_map_reserved_pages(void)
+{}
+
+void __weak crash_unmap_reserved_pages(void)
+{}
+
#ifdef CONFIG_COMPAT
asmlinkage long compat_sys_kexec_load(unsigned long entry,
unsigned long nr_segments,
@@ -1134,14 +1149,16 @@ int crash_shrink_memory(unsigned long ne
goto unlock;
}
- start = roundup(start, PAGE_SIZE);
- end = roundup(start + new_size, PAGE_SIZE);
+ start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
+ end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
+ crash_map_reserved_pages();
crash_free_reserved_phys_range(end, crashk_res.end);
if ((start == end) && (crashk_res.parent != NULL))
release_resource(&crashk_res);
crashk_res.end = end - 1;
+ crash_unmap_reserved_pages();
unlock:
mutex_unlock(&kexec_mutex);
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
2011-09-13 13:26 ` Michael Holzheu
@ 2011-09-13 13:26 ` Michael Holzheu
-1 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390
[-- Attachment #1: s390-kdump-arch-crash_map_pages.patch --]
[-- Type: text/plain, Size: 3308 bytes --]
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
This patch implements the crash_map_pages() function for s390.
KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support
kernel mappings that use large pages.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
arch/s390/include/asm/kexec.h | 3 +++
arch/s390/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++
arch/s390/kernel/setup.c | 10 ++++++----
3 files changed, 40 insertions(+), 4 deletions(-)
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -36,6 +36,9 @@
/* Allocate one page for the pdp and the second for the code */
#define KEXEC_CONTROL_PAGE_SIZE 4096
+/* Alignment of crashkernel memory */
+#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
+
/* The native architecture */
#define KEXEC_ARCH KEXEC_ARCH_S390
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
#endif
/*
+ * Map or unmap crashkernel memory
+ */
+static void crash_map_pages(int enable)
+{
+ unsigned long size = crashk_res.end - crashk_res.start + 1;
+
+ BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
+ size % KEXEC_CRASH_MEM_ALIGN);
+ if (enable)
+ vmem_add_mapping(crashk_res.start, size);
+ else
+ vmem_remove_mapping(crashk_res.start, size);
+}
+
+/*
+ * Map crashkernel memory
+ */
+void crash_map_reserved_pages(void)
+{
+ crash_map_pages(1);
+}
+
+/*
+ * Unmap crashkernel memory
+ */
+void crash_unmap_reserved_pages(void)
+{
+ crash_map_pages(0);
+}
+
+/*
* Give back memory to hypervisor before new kdump is loaded
*/
static int machine_kexec_prepare_kdump(void)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -446,6 +446,7 @@ static void __init setup_resources(void)
res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
switch (memory_chunk[i].type) {
case CHUNK_READ_WRITE:
+ case CHUNK_CRASHK:
res->name = "System RAM";
break;
case CHUNK_READ_ONLY:
@@ -706,8 +707,8 @@ static void __init reserve_crashkernel(v
&crash_base);
if (rc || crash_size == 0)
return;
- crash_base = PAGE_ALIGN(crash_base);
- crash_size = PAGE_ALIGN(crash_size);
+ crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
+ crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
if (register_memory_notifier(&kdump_mem_nb))
return;
if (!crash_base)
@@ -727,7 +728,7 @@ static void __init reserve_crashkernel(v
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
insert_resource(&iomem_resource, &crashk_res);
- reserve_kdump_bootmem(crash_base, crash_size, CHUNK_READ_WRITE);
+ reserve_kdump_bootmem(crash_base, crash_size, CHUNK_CRASHK);
pr_info("Reserving %lluMB of memory at %lluMB "
"for crashkernel (System RAM: %luMB)\n",
crash_size >> 20, crash_base >> 20, memory_end >> 20);
@@ -802,7 +803,8 @@ setup_memory(void)
for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
unsigned long start_chunk, end_chunk, pfn;
- if (memory_chunk[i].type != CHUNK_READ_WRITE)
+ if (memory_chunk[i].type != CHUNK_READ_WRITE &&
+ memory_chunk[i].type != CHUNK_CRASHK)
continue;
start_chunk = PFN_DOWN(memory_chunk[i].addr);
end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);
^ permalink raw reply [flat|nested] 16+ messages in thread
* [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
@ 2011-09-13 13:26 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-13 13:26 UTC (permalink / raw)
To: vgoyal, akpm
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, kexec
[-- Attachment #1: s390-kdump-arch-crash_map_pages.patch --]
[-- Type: text/plain, Size: 3452 bytes --]
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
This patch implements the crash_map_pages() function for s390.
KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support
kernel mappings that use large pages.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
arch/s390/include/asm/kexec.h | 3 +++
arch/s390/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++
arch/s390/kernel/setup.c | 10 ++++++----
3 files changed, 40 insertions(+), 4 deletions(-)
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -36,6 +36,9 @@
/* Allocate one page for the pdp and the second for the code */
#define KEXEC_CONTROL_PAGE_SIZE 4096
+/* Alignment of crashkernel memory */
+#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
+
/* The native architecture */
#define KEXEC_ARCH KEXEC_ARCH_S390
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
#endif
/*
+ * Map or unmap crashkernel memory
+ */
+static void crash_map_pages(int enable)
+{
+ unsigned long size = crashk_res.end - crashk_res.start + 1;
+
+ BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
+ size % KEXEC_CRASH_MEM_ALIGN);
+ if (enable)
+ vmem_add_mapping(crashk_res.start, size);
+ else
+ vmem_remove_mapping(crashk_res.start, size);
+}
+
+/*
+ * Map crashkernel memory
+ */
+void crash_map_reserved_pages(void)
+{
+ crash_map_pages(1);
+}
+
+/*
+ * Unmap crashkernel memory
+ */
+void crash_unmap_reserved_pages(void)
+{
+ crash_map_pages(0);
+}
+
+/*
* Give back memory to hypervisor before new kdump is loaded
*/
static int machine_kexec_prepare_kdump(void)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -446,6 +446,7 @@ static void __init setup_resources(void)
res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
switch (memory_chunk[i].type) {
case CHUNK_READ_WRITE:
+ case CHUNK_CRASHK:
res->name = "System RAM";
break;
case CHUNK_READ_ONLY:
@@ -706,8 +707,8 @@ static void __init reserve_crashkernel(v
&crash_base);
if (rc || crash_size == 0)
return;
- crash_base = PAGE_ALIGN(crash_base);
- crash_size = PAGE_ALIGN(crash_size);
+ crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
+ crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
if (register_memory_notifier(&kdump_mem_nb))
return;
if (!crash_base)
@@ -727,7 +728,7 @@ static void __init reserve_crashkernel(v
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
insert_resource(&iomem_resource, &crashk_res);
- reserve_kdump_bootmem(crash_base, crash_size, CHUNK_READ_WRITE);
+ reserve_kdump_bootmem(crash_base, crash_size, CHUNK_CRASHK);
pr_info("Reserving %lluMB of memory at %lluMB "
"for crashkernel (System RAM: %luMB)\n",
crash_size >> 20, crash_base >> 20, memory_end >> 20);
@@ -802,7 +803,8 @@ setup_memory(void)
for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
unsigned long start_chunk, end_chunk, pfn;
- if (memory_chunk[i].type != CHUNK_READ_WRITE)
+ if (memory_chunk[i].type != CHUNK_READ_WRITE &&
+ memory_chunk[i].type != CHUNK_CRASHK)
continue;
start_chunk = PFN_DOWN(memory_chunk[i].addr);
end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 1/2] kdump: Add infrastructure for unmapping crashkernel memory
2011-09-13 13:26 ` Michael Holzheu
@ 2011-09-13 13:40 ` Vivek Goyal
-1 siblings, 0 replies; 16+ messages in thread
From: Vivek Goyal @ 2011-09-13 13:40 UTC (permalink / raw)
To: Michael Holzheu
Cc: akpm, ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390
On Tue, Sep 13, 2011 at 03:26:36PM +0200, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> This patch introduces a mechanism that allows architecture backends to
> remove page tables for the crashkernel memory. This can protect the loaded
> kdump kernel from being overwritten by broken kernel code. Two new
> functions crash_map_reserved_pages() and crash_unmap_reserved_pages() are
> added that can be implemented by architecture code. The
> crash_map_reserved_pages() function is called before and
> crash_unmap_reserved_pages() after the crashkernel segments are loaded. The
> functions are also called in crash_shrink_memory() to create/remove page
> tables when the crashkernel memory size is reduced.
>
> To support architectures that have large pages this patch also introduces
> a new define KEXEC_CRASH_MEM_ALIGN. The crashkernel start and size must
> always be aligned with KEXEC_CRASH_MEM_ALIGN.
>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Looks reasonable conceptually. Hence...
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Thanks
Vivek
> ---
> include/linux/kexec.h | 6 ++++++
> kernel/kexec.c | 21 +++++++++++++++++++--
> 2 files changed, 25 insertions(+), 2 deletions(-)
>
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -37,6 +37,10 @@
> #define KEXEC_CRASH_CONTROL_MEMORY_LIMIT KEXEC_CONTROL_MEMORY_LIMIT
> #endif
>
> +#ifndef KEXEC_CRASH_MEM_ALIGN
> +#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> +#endif
> +
> #define KEXEC_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
> #define KEXEC_CORE_NOTE_NAME "CORE"
> #define KEXEC_CORE_NOTE_NAME_BYTES ALIGN(sizeof(KEXEC_CORE_NOTE_NAME), 4)
> @@ -133,6 +137,8 @@ extern void crash_kexec(struct pt_regs *
> int kexec_should_crash(struct task_struct *);
> void crash_save_cpu(struct pt_regs *regs, int cpu);
> void crash_save_vmcoreinfo(void);
> +void crash_map_reserved_pages(void);
> +void crash_unmap_reserved_pages(void);
> void arch_crash_save_vmcoreinfo(void);
> void vmcoreinfo_append_str(const char *fmt, ...)
> __attribute__ ((format (printf, 1, 2)));
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -999,6 +999,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> kimage_free(xchg(&kexec_crash_image, NULL));
> result = kimage_crash_alloc(&image, entry,
> nr_segments, segments);
> + crash_map_reserved_pages();
> }
> if (result)
> goto out;
> @@ -1015,6 +1016,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> goto out;
> }
> kimage_terminate(image);
> + if (flags & KEXEC_ON_CRASH)
> + crash_unmap_reserved_pages();
> }
> /* Install the new kernel, and Uninstall the old */
> image = xchg(dest_image, image);
> @@ -1026,6 +1029,18 @@ out:
> return result;
> }
>
> +/*
> + * Add and remove page tables for crashkernel memory
> + *
> + * Provide an empty default implementation here -- architecture
> + * code may override this
> + */
> +void __weak crash_map_reserved_pages(void)
> +{}
> +
> +void __weak crash_unmap_reserved_pages(void)
> +{}
> +
> #ifdef CONFIG_COMPAT
> asmlinkage long compat_sys_kexec_load(unsigned long entry,
> unsigned long nr_segments,
> @@ -1134,14 +1149,16 @@ int crash_shrink_memory(unsigned long ne
> goto unlock;
> }
>
> - start = roundup(start, PAGE_SIZE);
> - end = roundup(start + new_size, PAGE_SIZE);
> + start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
> + end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
>
> + crash_map_reserved_pages();
> crash_free_reserved_phys_range(end, crashk_res.end);
>
> if ((start == end) && (crashk_res.parent != NULL))
> release_resource(&crashk_res);
> crashk_res.end = end - 1;
> + crash_unmap_reserved_pages();
>
> unlock:
> mutex_unlock(&kexec_mutex);
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 1/2] kdump: Add infrastructure for unmapping crashkernel memory
@ 2011-09-13 13:40 ` Vivek Goyal
0 siblings, 0 replies; 16+ messages in thread
From: Vivek Goyal @ 2011-09-13 13:40 UTC (permalink / raw)
To: Michael Holzheu
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, akpm, kexec
On Tue, Sep 13, 2011 at 03:26:36PM +0200, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> This patch introduces a mechanism that allows architecture backends to
> remove page tables for the crashkernel memory. This can protect the loaded
> kdump kernel from being overwritten by broken kernel code. Two new
> functions crash_map_reserved_pages() and crash_unmap_reserved_pages() are
> added that can be implemented by architecture code. The
> crash_map_reserved_pages() function is called before and
> crash_unmap_reserved_pages() after the crashkernel segments are loaded. The
> functions are also called in crash_shrink_memory() to create/remove page
> tables when the crashkernel memory size is reduced.
>
> To support architectures that have large pages this patch also introduces
> a new define KEXEC_CRASH_MEM_ALIGN. The crashkernel start and size must
> always be aligned with KEXEC_CRASH_MEM_ALIGN.
>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Looks reasonable conceptually. Hence...
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Thanks
Vivek
> ---
> include/linux/kexec.h | 6 ++++++
> kernel/kexec.c | 21 +++++++++++++++++++--
> 2 files changed, 25 insertions(+), 2 deletions(-)
>
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -37,6 +37,10 @@
> #define KEXEC_CRASH_CONTROL_MEMORY_LIMIT KEXEC_CONTROL_MEMORY_LIMIT
> #endif
>
> +#ifndef KEXEC_CRASH_MEM_ALIGN
> +#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> +#endif
> +
> #define KEXEC_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
> #define KEXEC_CORE_NOTE_NAME "CORE"
> #define KEXEC_CORE_NOTE_NAME_BYTES ALIGN(sizeof(KEXEC_CORE_NOTE_NAME), 4)
> @@ -133,6 +137,8 @@ extern void crash_kexec(struct pt_regs *
> int kexec_should_crash(struct task_struct *);
> void crash_save_cpu(struct pt_regs *regs, int cpu);
> void crash_save_vmcoreinfo(void);
> +void crash_map_reserved_pages(void);
> +void crash_unmap_reserved_pages(void);
> void arch_crash_save_vmcoreinfo(void);
> void vmcoreinfo_append_str(const char *fmt, ...)
> __attribute__ ((format (printf, 1, 2)));
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -999,6 +999,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> kimage_free(xchg(&kexec_crash_image, NULL));
> result = kimage_crash_alloc(&image, entry,
> nr_segments, segments);
> + crash_map_reserved_pages();
> }
> if (result)
> goto out;
> @@ -1015,6 +1016,8 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> goto out;
> }
> kimage_terminate(image);
> + if (flags & KEXEC_ON_CRASH)
> + crash_unmap_reserved_pages();
> }
> /* Install the new kernel, and Uninstall the old */
> image = xchg(dest_image, image);
> @@ -1026,6 +1029,18 @@ out:
> return result;
> }
>
> +/*
> + * Add and remove page tables for crashkernel memory
> + *
> + * Provide an empty default implementation here -- architecture
> + * code may override this
> + */
> +void __weak crash_map_reserved_pages(void)
> +{}
> +
> +void __weak crash_unmap_reserved_pages(void)
> +{}
> +
> #ifdef CONFIG_COMPAT
> asmlinkage long compat_sys_kexec_load(unsigned long entry,
> unsigned long nr_segments,
> @@ -1134,14 +1149,16 @@ int crash_shrink_memory(unsigned long ne
> goto unlock;
> }
>
> - start = roundup(start, PAGE_SIZE);
> - end = roundup(start + new_size, PAGE_SIZE);
> + start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
> + end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
>
> + crash_map_reserved_pages();
> crash_free_reserved_phys_range(end, crashk_res.end);
>
> if ((start == end) && (crashk_res.parent != NULL))
> release_resource(&crashk_res);
> crashk_res.end = end - 1;
> + crash_unmap_reserved_pages();
>
> unlock:
> mutex_unlock(&kexec_mutex);
_______________________________________________
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kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
2011-09-13 13:26 ` Michael Holzheu
@ 2011-09-13 21:52 ` Andrew Morton
-1 siblings, 0 replies; 16+ messages in thread
From: Andrew Morton @ 2011-09-13 21:52 UTC (permalink / raw)
To: Michael Holzheu
Cc: vgoyal, ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390, Andrew Morton
On Tue, 13 Sep 2011 15:26:37 +0200
Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> This patch implements the crash_map_pages() function for s390.
> KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support
> kernel mappings that use large pages.
>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> ---
> arch/s390/include/asm/kexec.h | 3 +++
> arch/s390/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++
> arch/s390/kernel/setup.c | 10 ++++++----
> 3 files changed, 40 insertions(+), 4 deletions(-)
>
> --- a/arch/s390/include/asm/kexec.h
> +++ b/arch/s390/include/asm/kexec.h
> @@ -36,6 +36,9 @@
> /* Allocate one page for the pdp and the second for the code */
> #define KEXEC_CONTROL_PAGE_SIZE 4096
>
> +/* Alignment of crashkernel memory */
> +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
Why not make this unconditional, for all architectures which support
hugepages? ie:
#ifdef HPAGE_SIZE
#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
#else
#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
#endif
in include/linux/kexec.h?
IOW, what are the compromises here?
Also, does s390 support CONFIG_HUGETLB_PAGE=n? If so, does the use of
HPAGE_SIZE still make sense? Does it compile?
> /* The native architecture */
> #define KEXEC_ARCH KEXEC_ARCH_S390
>
> --- a/arch/s390/kernel/machine_kexec.c
> +++ b/arch/s390/kernel/machine_kexec.c
> @@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
> #endif
>
> /*
> + * Map or unmap crashkernel memory
> + */
> +static void crash_map_pages(int enable)
> +{
> + unsigned long size = crashk_res.end - crashk_res.start + 1;
resource_size().
> + BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
> + size % KEXEC_CRASH_MEM_ALIGN);
> + if (enable)
> + vmem_add_mapping(crashk_res.start, size);
> + else
> + vmem_remove_mapping(crashk_res.start, size);
> +}
>
> ...
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
@ 2011-09-13 21:52 ` Andrew Morton
0 siblings, 0 replies; 16+ messages in thread
From: Andrew Morton @ 2011-09-13 21:52 UTC (permalink / raw)
To: Michael Holzheu
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, Andrew Morton, kexec, vgoyal
On Tue, 13 Sep 2011 15:26:37 +0200
Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
>
> This patch implements the crash_map_pages() function for s390.
> KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support
> kernel mappings that use large pages.
>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> ---
> arch/s390/include/asm/kexec.h | 3 +++
> arch/s390/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++
> arch/s390/kernel/setup.c | 10 ++++++----
> 3 files changed, 40 insertions(+), 4 deletions(-)
>
> --- a/arch/s390/include/asm/kexec.h
> +++ b/arch/s390/include/asm/kexec.h
> @@ -36,6 +36,9 @@
> /* Allocate one page for the pdp and the second for the code */
> #define KEXEC_CONTROL_PAGE_SIZE 4096
>
> +/* Alignment of crashkernel memory */
> +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
Why not make this unconditional, for all architectures which support
hugepages? ie:
#ifdef HPAGE_SIZE
#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
#else
#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
#endif
in include/linux/kexec.h?
IOW, what are the compromises here?
Also, does s390 support CONFIG_HUGETLB_PAGE=n? If so, does the use of
HPAGE_SIZE still make sense? Does it compile?
> /* The native architecture */
> #define KEXEC_ARCH KEXEC_ARCH_S390
>
> --- a/arch/s390/kernel/machine_kexec.c
> +++ b/arch/s390/kernel/machine_kexec.c
> @@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
> #endif
>
> /*
> + * Map or unmap crashkernel memory
> + */
> +static void crash_map_pages(int enable)
> +{
> + unsigned long size = crashk_res.end - crashk_res.start + 1;
resource_size().
> + BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
> + size % KEXEC_CRASH_MEM_ALIGN);
> + if (enable)
> + vmem_add_mapping(crashk_res.start, size);
> + else
> + vmem_remove_mapping(crashk_res.start, size);
> +}
>
> ...
>
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http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
2011-09-13 21:52 ` Andrew Morton
@ 2011-09-14 8:58 ` Michael Holzheu
-1 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-14 8:58 UTC (permalink / raw)
To: Andrew Morton
Cc: vgoyal, ebiederm, mahesh, schwidefsky, heiko.carstens, kexec,
linux-kernel, linux-s390, Andrew Morton
Hello Andrew,
On Tue, 2011-09-13 at 14:52 -0700, Andrew Morton wrote:
> On Tue, 13 Sep 2011 15:26:37 +0200
> Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
[snip]
> > --- a/arch/s390/include/asm/kexec.h
> > +++ b/arch/s390/include/asm/kexec.h
> > @@ -36,6 +36,9 @@
> > /* Allocate one page for the pdp and the second for the code */
> > #define KEXEC_CONTROL_PAGE_SIZE 4096
> >
> > +/* Alignment of crashkernel memory */
> > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
>
> Why not make this unconditional, for all architectures which support
> hugepages? ie:
>
> #ifdef HPAGE_SIZE
> #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> #else
> #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> #endif
> in include/linux/kexec.h?
>
> IOW, what are the compromises here?
If we would do it that way, crashkernel memory on architectures that
support large pages but do not support unmapping of crashkernel memory
would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
would be necessary in that case.
If that is acceptable I have no problem to define that unconditional for
all architectures. Vivek what do you think?
>
> Also, does s390 support CONFIG_HUGETLB_PAGE=n? If so, does the use of
> HPAGE_SIZE still make sense? Does it compile?
Yes, s390 supports CONFIG_HUGETLB_PAGE=n and it still compiles in that
case. For us it is ok to use HPAGE_SIZE crashkernel alignment also for
kernels with CONFIG_HUGETLB_PAGE=n.
>
>
> > /* The native architecture */
> > #define KEXEC_ARCH KEXEC_ARCH_S390
> >
> > --- a/arch/s390/kernel/machine_kexec.c
> > +++ b/arch/s390/kernel/machine_kexec.c
> > @@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
> > #endif
> >
> > /*
> > + * Map or unmap crashkernel memory
> > + */
> > +static void crash_map_pages(int enable)
> > +{
> > + unsigned long size = crashk_res.end - crashk_res.start + 1;
>
> resource_size().
Ok I will use that. Thanks for the hint.
Michael
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
@ 2011-09-14 8:58 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-14 8:58 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-s390, mahesh, heiko.carstens, linux-kernel, ebiederm,
schwidefsky, Andrew Morton, kexec, vgoyal
Hello Andrew,
On Tue, 2011-09-13 at 14:52 -0700, Andrew Morton wrote:
> On Tue, 13 Sep 2011 15:26:37 +0200
> Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
[snip]
> > --- a/arch/s390/include/asm/kexec.h
> > +++ b/arch/s390/include/asm/kexec.h
> > @@ -36,6 +36,9 @@
> > /* Allocate one page for the pdp and the second for the code */
> > #define KEXEC_CONTROL_PAGE_SIZE 4096
> >
> > +/* Alignment of crashkernel memory */
> > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
>
> Why not make this unconditional, for all architectures which support
> hugepages? ie:
>
> #ifdef HPAGE_SIZE
> #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> #else
> #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> #endif
> in include/linux/kexec.h?
>
> IOW, what are the compromises here?
If we would do it that way, crashkernel memory on architectures that
support large pages but do not support unmapping of crashkernel memory
would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
would be necessary in that case.
If that is acceptable I have no problem to define that unconditional for
all architectures. Vivek what do you think?
>
> Also, does s390 support CONFIG_HUGETLB_PAGE=n? If so, does the use of
> HPAGE_SIZE still make sense? Does it compile?
Yes, s390 supports CONFIG_HUGETLB_PAGE=n and it still compiles in that
case. For us it is ok to use HPAGE_SIZE crashkernel alignment also for
kernels with CONFIG_HUGETLB_PAGE=n.
>
>
> > /* The native architecture */
> > #define KEXEC_ARCH KEXEC_ARCH_S390
> >
> > --- a/arch/s390/kernel/machine_kexec.c
> > +++ b/arch/s390/kernel/machine_kexec.c
> > @@ -243,6 +243,37 @@ static void __machine_kdump(void *image)
> > #endif
> >
> > /*
> > + * Map or unmap crashkernel memory
> > + */
> > +static void crash_map_pages(int enable)
> > +{
> > + unsigned long size = crashk_res.end - crashk_res.start + 1;
>
> resource_size().
Ok I will use that. Thanks for the hint.
Michael
_______________________________________________
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kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
2011-09-14 8:58 ` Michael Holzheu
@ 2011-09-14 18:29 ` Vivek Goyal
-1 siblings, 0 replies; 16+ messages in thread
From: Vivek Goyal @ 2011-09-14 18:29 UTC (permalink / raw)
To: Michael Holzheu
Cc: Andrew Morton, ebiederm, mahesh, schwidefsky, heiko.carstens,
kexec, linux-kernel, linux-s390, Andrew Morton
On Wed, Sep 14, 2011 at 10:58:28AM +0200, Michael Holzheu wrote:
> Hello Andrew,
>
> On Tue, 2011-09-13 at 14:52 -0700, Andrew Morton wrote:
> > On Tue, 13 Sep 2011 15:26:37 +0200
> > Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
>
> [snip]
>
> > > --- a/arch/s390/include/asm/kexec.h
> > > +++ b/arch/s390/include/asm/kexec.h
> > > @@ -36,6 +36,9 @@
> > > /* Allocate one page for the pdp and the second for the code */
> > > #define KEXEC_CONTROL_PAGE_SIZE 4096
> > >
> > > +/* Alignment of crashkernel memory */
> > > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> >
> > Why not make this unconditional, for all architectures which support
> > hugepages? ie:
> >
> > #ifdef HPAGE_SIZE
> > #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> > #else
> > #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> > #endif
>
> > in include/linux/kexec.h?
> >
> > IOW, what are the compromises here?
>
> If we would do it that way, crashkernel memory on architectures that
> support large pages but do not support unmapping of crashkernel memory
> would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
> would be necessary in that case.
>
> If that is acceptable I have no problem to define that unconditional for
> all architectures. Vivek what do you think?
As PAGE_SIZE alignment is sufficient for rest of the architecture, I
am fine with keeping it in arch dependent files.
Thanks
Vivek
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
@ 2011-09-14 18:29 ` Vivek Goyal
0 siblings, 0 replies; 16+ messages in thread
From: Vivek Goyal @ 2011-09-14 18:29 UTC (permalink / raw)
To: Michael Holzheu
Cc: Andrew Morton, linux-s390, mahesh, heiko.carstens, linux-kernel,
ebiederm, schwidefsky, Andrew Morton, kexec
On Wed, Sep 14, 2011 at 10:58:28AM +0200, Michael Holzheu wrote:
> Hello Andrew,
>
> On Tue, 2011-09-13 at 14:52 -0700, Andrew Morton wrote:
> > On Tue, 13 Sep 2011 15:26:37 +0200
> > Michael Holzheu <holzheu@linux.vnet.ibm.com> wrote:
>
> [snip]
>
> > > --- a/arch/s390/include/asm/kexec.h
> > > +++ b/arch/s390/include/asm/kexec.h
> > > @@ -36,6 +36,9 @@
> > > /* Allocate one page for the pdp and the second for the code */
> > > #define KEXEC_CONTROL_PAGE_SIZE 4096
> > >
> > > +/* Alignment of crashkernel memory */
> > > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> >
> > Why not make this unconditional, for all architectures which support
> > hugepages? ie:
> >
> > #ifdef HPAGE_SIZE
> > #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> > #else
> > #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> > #endif
>
> > in include/linux/kexec.h?
> >
> > IOW, what are the compromises here?
>
> If we would do it that way, crashkernel memory on architectures that
> support large pages but do not support unmapping of crashkernel memory
> would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
> would be necessary in that case.
>
> If that is acceptable I have no problem to define that unconditional for
> all architectures. Vivek what do you think?
As PAGE_SIZE alignment is sufficient for rest of the architecture, I
am fine with keeping it in arch dependent files.
Thanks
Vivek
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kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
2011-09-14 18:29 ` Vivek Goyal
@ 2011-09-15 8:48 ` Michael Holzheu
-1 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-15 8:48 UTC (permalink / raw)
To: Vivek Goyal
Cc: Andrew Morton, ebiederm, mahesh, schwidefsky, heiko.carstens,
kexec, linux-kernel, linux-s390, Andrew Morton
Hello Vivek, Andrew,
On Wed, 2011-09-14 at 14:29 -0400, Vivek Goyal wrote:
> On Wed, Sep 14, 2011 at 10:58:28AM +0200, Michael Holzheu wrote:
> > > Why not make this unconditional, for all architectures which support
> > > hugepages? ie:
> > >
> > > #ifdef HPAGE_SIZE
> > > #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> > > #else
> > > #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> > > #endif
> >
> > > in include/linux/kexec.h?
> > >
> > > IOW, what are the compromises here?
> >
> > If we would do it that way, crashkernel memory on architectures that
> > support large pages but do not support unmapping of crashkernel memory
> > would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
> > would be necessary in that case.
> >
> > If that is acceptable I have no problem to define that unconditional for
> > all architectures. Vivek what do you think?
>
> As PAGE_SIZE alignment is sufficient for rest of the architecture, I
> am fine with keeping it in arch dependent files.
Ok fine. So I will resend the two patches including Andrew's
resource_size() fix and keep KEXEC_CRASH_MEM_ALIGN definition
architecture dependent.
Michael
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory
@ 2011-09-15 8:48 ` Michael Holzheu
0 siblings, 0 replies; 16+ messages in thread
From: Michael Holzheu @ 2011-09-15 8:48 UTC (permalink / raw)
To: Vivek Goyal
Cc: Andrew Morton, linux-s390, mahesh, heiko.carstens, linux-kernel,
ebiederm, schwidefsky, Andrew Morton, kexec
Hello Vivek, Andrew,
On Wed, 2011-09-14 at 14:29 -0400, Vivek Goyal wrote:
> On Wed, Sep 14, 2011 at 10:58:28AM +0200, Michael Holzheu wrote:
> > > Why not make this unconditional, for all architectures which support
> > > hugepages? ie:
> > >
> > > #ifdef HPAGE_SIZE
> > > #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE
> > > #else
> > > #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
> > > #endif
> >
> > > in include/linux/kexec.h?
> > >
> > > IOW, what are the compromises here?
> >
> > If we would do it that way, crashkernel memory on architectures that
> > support large pages but do not support unmapping of crashkernel memory
> > would always be aligned to HPAGE_SIZE. But only PAGE_SIZE alignment
> > would be necessary in that case.
> >
> > If that is acceptable I have no problem to define that unconditional for
> > all architectures. Vivek what do you think?
>
> As PAGE_SIZE alignment is sufficient for rest of the architecture, I
> am fine with keeping it in arch dependent files.
Ok fine. So I will resend the two patches including Andrew's
resource_size() fix and keep KEXEC_CRASH_MEM_ALIGN definition
architecture dependent.
Michael
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^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2011-09-15 8:48 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-09-13 13:26 [patch v2 0/2] kdump: Allow removal of page tables for crashkernel memory Michael Holzheu
2011-09-13 13:26 ` Michael Holzheu
2011-09-13 13:26 ` [patch v2 1/2] kdump: Add infrastructure for unmapping " Michael Holzheu
2011-09-13 13:26 ` Michael Holzheu
2011-09-13 13:40 ` Vivek Goyal
2011-09-13 13:40 ` Vivek Goyal
2011-09-13 13:26 ` [patch v2 2/2] s390: Add architecture code " Michael Holzheu
2011-09-13 13:26 ` Michael Holzheu
2011-09-13 21:52 ` Andrew Morton
2011-09-13 21:52 ` Andrew Morton
2011-09-14 8:58 ` Michael Holzheu
2011-09-14 8:58 ` Michael Holzheu
2011-09-14 18:29 ` Vivek Goyal
2011-09-14 18:29 ` Vivek Goyal
2011-09-15 8:48 ` Michael Holzheu
2011-09-15 8:48 ` Michael Holzheu
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