[PATCH] kexec/kdump: Use generic elf code on ia64

[PATCH] kexec/kdump: Use generic elf code on ia64

[Simon Horman]

Make use of the generic implementation of crash_save_cpu().

On ia64 the registers are saved by a kdump-specific function
ia64_dump_cpu_regs() rather than elf_core_copy_regs() which 
is used by other architectures via crash_save_cpu(). It seems
that ia64_dump_cpu_regs() and elf_core_copy_regs() are indeed
quite different

In order to facilitate this kdump_elf_core_copy_regs()
has been created, and it is called by crash_save_cpu().
By default kdump_elf_core_copy_regs() is just defined to be
elf_core_copy_regs() and ia64 defines its own implementation,
which calls ia64_dump_cpu_regs().  The ia64 version also sets
register 47 in accordance with the code that it replaces.

The code appears to work, however as the place where the registers
are captured has changed natrually some of their values have also changed.
This makes looking for problems by comparing the new and old output a
little tricky.

Signed-off-by: Simon Horman <horms@verge.net.au>

--- 
This patch applies on top of the note size calculation patch
that can be found in mm and at
http://lists.linux-foundation.org/pipermail/fastboot/2007-April/006792.html

Porting this patch to not require that one is quite trivial.
I can supply a port or a thread containing both patches if it helps.

 arch/ia64/kernel/crash.c         |   46 ++------------------------------------
 arch/ia64/kernel/machine_kexec.c |    2 -
 include/asm/kexec.h              |    7 ++++-
 include/linux/kexec.h            |    5 ++++
 kernel/kexec.c                   |    2 -
 5 files changed, 16 insertions(+), 46 deletions(-)

Index: linux-2.6/arch/ia64/kernel/crash.c
=================================--- linux-2.6.orig/arch/ia64/kernel/crash.c	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/arch/ia64/kernel/crash.c	2007-04-16 16:14:52.000000000 +0900
@@ -25,44 +25,11 @@
 atomic_t kdump_in_progress;
 static int kdump_on_init = 1;
 
-static inline Elf64_Word
-*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
-		size_t data_len)
-{
-	struct elf_note *note = (struct elf_note *)buf;
-	note->n_namesz = strlen(name) + 1;
-	note->n_descsz = data_len;
-	note->n_type   = type;
-	buf += (sizeof(*note) + 3)/4;
-	memcpy(buf, name, note->n_namesz);
-	buf += (note->n_namesz + 3)/4;
-	memcpy(buf, data, data_len);
-	buf += (data_len + 3)/4;
-	return buf;
-}
-
-static void
-final_note(void *buf)
-{
-	memset(buf, 0, sizeof(struct elf_note));
-}
-
-extern void ia64_dump_cpu_regs(void *);
-
-static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
-
 void
-crash_save_this_cpu(void)
+ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
 {
-	void *buf;
 	unsigned long cfm, sof, sol;
-
-	int cpu = smp_processor_id();
-	struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
-
-	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
-	memset(prstatus, 0, sizeof(*prstatus));
-	prstatus->pr_pid = current->pid;
+	elf_greg_t *dst = (elf_greg_t *)elfregs;
 
 	ia64_dump_cpu_regs(dst);
 	cfm = dst[43];
@@ -70,13 +37,6 @@
 	sof = cfm & 0x7f;
 	dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
 			sof - sol);
-
-	buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
-	if (!buf)
-		return;
-	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
-			sizeof(*prstatus));
-	final_note(buf);
 }
 
 #ifdef CONFIG_SMP
@@ -134,7 +94,7 @@
 	int cpuid;
 	local_irq_disable();
 	cpuid = smp_processor_id();
-	crash_save_this_cpu();
+	crash_save_cpu(NULL, smp_processor_id());
 	current->thread.ksp = (__u64)info->sw - 16;
 	atomic_inc(&kdump_cpu_frozen);
 	kdump_status[cpuid] = 1;
Index: linux-2.6/include/asm/kexec.h
=================================--- linux-2.6.orig/include/asm/kexec.h	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/include/asm/kexec.h	2007-04-16 16:14:52.000000000 +0900
@@ -19,6 +19,9 @@
                 flush_icache_range(page_addr, page_addr + PAGE_SIZE); \
         } while(0)
 
+#define kexec_elf_core_copy_regs(elfregs, regs) \
+	ia64_kexec_elf_core_copy_regs(elfregs, regs)
+
 extern struct kimage *ia64_kimage;
 extern const unsigned int relocate_new_kernel_size;
 extern void relocate_new_kernel(unsigned long, unsigned long,
@@ -32,7 +35,9 @@
 extern void kdump_smp_send_stop(void);
 extern void kdump_smp_send_init(void);
 extern void kexec_disable_iosapic(void);
-extern void crash_save_this_cpu(void);
+extern void ia64_dump_cpu_regs(void *);
+extern void ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs,
+					  struct pt_regs *regs);
 struct rsvd_region;
 extern unsigned long kdump_find_rsvd_region(unsigned long size,
 		struct rsvd_region *rsvd_regions, int n);
Index: linux-2.6/include/linux/kexec.h
=================================--- linux-2.6.orig/include/linux/kexec.h	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/include/linux/kexec.h	2007-04-16 16:14:52.000000000 +0900
@@ -128,6 +128,11 @@
 #define kexec_flush_icache_page(page)
 #endif
 
+#ifndef kexec_elf_core_copy_regs
+#define kexec_elf_core_copy_regs(elfregs, regs) \
+	elf_core_copy_regs(elfregs, regs)
+#endif
+
 #define KEXEC_ON_CRASH  0x00000001
 #define KEXEC_ARCH_MASK 0xffff0000
 
Index: linux-2.6/kernel/kexec.c
=================================--- linux-2.6.orig/kernel/kexec.c	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/kernel/kexec.c	2007-04-16 16:14:52.000000000 +0900
@@ -1117,7 +1117,7 @@
 		return;
 	memset(&prstatus, 0, sizeof(prstatus));
 	prstatus.pr_pid = current->pid;
-	elf_core_copy_regs(&prstatus.pr_reg, regs);
+	kexec_elf_core_copy_regs(&prstatus.pr_reg, regs);
 	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
 		      	      &prstatus, sizeof(prstatus));
 	final_note(buf);
Index: linux-2.6/arch/ia64/kernel/machine_kexec.c
=================================--- linux-2.6.orig/arch/ia64/kernel/machine_kexec.c	2007-04-16 16:11:23.000000000 +0900
+++ linux-2.6/arch/ia64/kernel/machine_kexec.c	2007-04-16 16:14:52.000000000 +0900
@@ -84,7 +84,7 @@
 
 	BUG_ON(!image);
 	if (image->type = KEXEC_TYPE_CRASH) {
-		crash_save_this_cpu();
+		crash_save_cpu(NULL, smp_processor_id());
 		current->thread.ksp = (__u64)info->sw - 16;
 	}
 

Re: [PATCH] kexec/kdump: Use generic elf code on ia64

[Simon Horman]

Make use of the generic implementation of crash_save_cpu().

On ia64 the registers are saved by a kdump-specific function
ia64_dump_cpu_regs() rather than elf_core_copy_regs() which 
is used by other architectures via crash_save_cpu(). It seems
that ia64_dump_cpu_regs() and elf_core_copy_regs() are indeed
quite different

In order to facilitate this kdump_elf_core_copy_regs()
has been created, and it is called by crash_save_cpu().
By default kdump_elf_core_copy_regs() is just defined to be
elf_core_copy_regs() and ia64 defines its own implementation,
which calls ia64_dump_cpu_regs().  The ia64 version also sets
register 47 in accordance with the code that it replaces.

The code appears to work, however as the place where the registers
are captured has changed natrually some of their values have also changed.
This makes looking for problems by comparing the new and old output a
little tricky.

Signed-off-by: Simon Horman <horms@verge.net.au>

--- 
* This patch applies on top of the note size calculation patch
  that can be found in mm and at
  http://lists.linux-foundation.org/pipermail/fastboot/2007-April/006792.html

  Porting this patch to not require that one is quite trivial.
  I can supply a port or a thread containing both patches if it helps.

* Update
  Diff against include/asm-ia64/kexec.h instead of include/asm/kexec.h
  Ooops!

 arch/ia64/kernel/crash.c         |   46 ++------------------------------------
 arch/ia64/kernel/machine_kexec.c |    2 -
 include/asm-ia64/kexec.h              |    7 ++++-
 include/linux/kexec.h            |    5 ++++
 kernel/kexec.c                   |    2 -
 5 files changed, 16 insertions(+), 46 deletions(-)

Index: linux-2.6/arch/ia64/kernel/crash.c
=================================--- linux-2.6.orig/arch/ia64/kernel/crash.c	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/arch/ia64/kernel/crash.c	2007-04-16 16:14:52.000000000 +0900
@@ -25,44 +25,11 @@
 atomic_t kdump_in_progress;
 static int kdump_on_init = 1;
 
-static inline Elf64_Word
-*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
-		size_t data_len)
-{
-	struct elf_note *note = (struct elf_note *)buf;
-	note->n_namesz = strlen(name) + 1;
-	note->n_descsz = data_len;
-	note->n_type   = type;
-	buf += (sizeof(*note) + 3)/4;
-	memcpy(buf, name, note->n_namesz);
-	buf += (note->n_namesz + 3)/4;
-	memcpy(buf, data, data_len);
-	buf += (data_len + 3)/4;
-	return buf;
-}
-
-static void
-final_note(void *buf)
-{
-	memset(buf, 0, sizeof(struct elf_note));
-}
-
-extern void ia64_dump_cpu_regs(void *);
-
-static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
-
 void
-crash_save_this_cpu(void)
+ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
 {
-	void *buf;
 	unsigned long cfm, sof, sol;
-
-	int cpu = smp_processor_id();
-	struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
-
-	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
-	memset(prstatus, 0, sizeof(*prstatus));
-	prstatus->pr_pid = current->pid;
+	elf_greg_t *dst = (elf_greg_t *)elfregs;
 
 	ia64_dump_cpu_regs(dst);
 	cfm = dst[43];
@@ -70,13 +37,6 @@
 	sof = cfm & 0x7f;
 	dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
 			sof - sol);
-
-	buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
-	if (!buf)
-		return;
-	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
-			sizeof(*prstatus));
-	final_note(buf);
 }
 
 #ifdef CONFIG_SMP
@@ -134,7 +94,7 @@
 	int cpuid;
 	local_irq_disable();
 	cpuid = smp_processor_id();
-	crash_save_this_cpu();
+	crash_save_cpu(NULL, smp_processor_id());
 	current->thread.ksp = (__u64)info->sw - 16;
 	atomic_inc(&kdump_cpu_frozen);
 	kdump_status[cpuid] = 1;
Index: linux-2.6/include/asm/kexec.h
=================================--- linux-2.6.orig/include/asm-ia64/kexec.h	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/include/asm-ia64/kexec.h	2007-04-16 16:14:52.000000000 +0900
@@ -19,6 +19,9 @@
                 flush_icache_range(page_addr, page_addr + PAGE_SIZE); \
         } while(0)
 
+#define kexec_elf_core_copy_regs(elfregs, regs) \
+	ia64_kexec_elf_core_copy_regs(elfregs, regs)
+
 extern struct kimage *ia64_kimage;
 extern const unsigned int relocate_new_kernel_size;
 extern void relocate_new_kernel(unsigned long, unsigned long,
@@ -32,7 +35,9 @@
 extern void kdump_smp_send_stop(void);
 extern void kdump_smp_send_init(void);
 extern void kexec_disable_iosapic(void);
-extern void crash_save_this_cpu(void);
+extern void ia64_dump_cpu_regs(void *);
+extern void ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs,
+					  struct pt_regs *regs);
 struct rsvd_region;
 extern unsigned long kdump_find_rsvd_region(unsigned long size,
 		struct rsvd_region *rsvd_regions, int n);
Index: linux-2.6/include/linux/kexec.h
=================================--- linux-2.6.orig/include/linux/kexec.h	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/include/linux/kexec.h	2007-04-16 16:14:52.000000000 +0900
@@ -128,6 +128,11 @@
 #define kexec_flush_icache_page(page)
 #endif
 
+#ifndef kexec_elf_core_copy_regs
+#define kexec_elf_core_copy_regs(elfregs, regs) \
+	elf_core_copy_regs(elfregs, regs)
+#endif
+
 #define KEXEC_ON_CRASH  0x00000001
 #define KEXEC_ARCH_MASK 0xffff0000
 
Index: linux-2.6/kernel/kexec.c
=================================--- linux-2.6.orig/kernel/kexec.c	2007-04-16 16:13:57.000000000 +0900
+++ linux-2.6/kernel/kexec.c	2007-04-16 16:14:52.000000000 +0900
@@ -1117,7 +1117,7 @@
 		return;
 	memset(&prstatus, 0, sizeof(prstatus));
 	prstatus.pr_pid = current->pid;
-	elf_core_copy_regs(&prstatus.pr_reg, regs);
+	kexec_elf_core_copy_regs(&prstatus.pr_reg, regs);
 	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
 		      	      &prstatus, sizeof(prstatus));
 	final_note(buf);
Index: linux-2.6/arch/ia64/kernel/machine_kexec.c
=================================--- linux-2.6.orig/arch/ia64/kernel/machine_kexec.c	2007-04-16 16:11:23.000000000 +0900
+++ linux-2.6/arch/ia64/kernel/machine_kexec.c	2007-04-16 16:14:52.000000000 +0900
@@ -84,7 +84,7 @@
 
 	BUG_ON(!image);
 	if (image->type = KEXEC_TYPE_CRASH) {
-		crash_save_this_cpu();
+		crash_save_cpu(NULL, smp_processor_id());
 		current->thread.ksp = (__u64)info->sw - 16;
 	}
 

RE: [PATCH] kexec/kdump: Use generic elf code on ia64

[Zou, Nanhai]

> -----Original Message-----
> From: Simon Horman [mailto:horms@verge.net.au]
> Sent: 2007Äê4ÔÂ16ÈÕ 16:21
> To: fastboot@lists.osdl.org; linux-ia64@vger.kernel.org
> Cc: Vivek Goyal; Luck, Tony; Zou, Nanhai
> Subject: Re: [PATCH] kexec/kdump: Use generic elf code on ia64
> 
> Make use of the generic implementation of crash_save_cpu().
> 
> On ia64 the registers are saved by a kdump-specific function
> ia64_dump_cpu_regs() rather than elf_core_copy_regs() which
> is used by other architectures via crash_save_cpu(). It seems
> that ia64_dump_cpu_regs() and elf_core_copy_regs() are indeed
> quite different
> 
> In order to facilitate this kdump_elf_core_copy_regs()
> has been created, and it is called by crash_save_cpu().
> By default kdump_elf_core_copy_regs() is just defined to be
> elf_core_copy_regs() and ia64 defines its own implementation,
> which calls ia64_dump_cpu_regs().  The ia64 version also sets
> register 47 in accordance with the code that it replaces.
> 
> The code appears to work, however as the place where the registers
> are captured has changed natrually some of their values have also changed.
> This makes looking for problems by comparing the new and old output a
> little tricky.
> 
> Signed-off-by: Simon Horman <horms@verge.net.au>
> 
> ---
> * This patch applies on top of the note size calculation patch
>   that can be found in mm and at
> 
> http://lists.linux-foundation.org/pipermail/fastboot/2007-April/006792.htm
> l
> 
>   Porting this patch to not require that one is quite trivial.
>   I can supply a port or a thread containing both patches if it helps.
> 
> * Update
>   Diff against include/asm-ia64/kexec.h instead of include/asm/kexec.h
>   Ooops!
> 
>  arch/ia64/kernel/crash.c         |   46
> ++------------------------------------
>  arch/ia64/kernel/machine_kexec.c |    2 -
>  include/asm-ia64/kexec.h              |    7 ++++-
>  include/linux/kexec.h            |    5 ++++
>  kernel/kexec.c                   |    2 -
>  5 files changed, 16 insertions(+), 46 deletions(-)
> 
> Index: linux-2.6/arch/ia64/kernel/crash.c
> =================================> --- linux-2.6.orig/arch/ia64/kernel/crash.c	2007-04-16
> 16:13:57.000000000 +0900
> +++ linux-2.6/arch/ia64/kernel/crash.c	2007-04-16 16:14:52.000000000
> +0900
> @@ -25,44 +25,11 @@
>  atomic_t kdump_in_progress;
>  static int kdump_on_init = 1;
> 
> -static inline Elf64_Word
> -*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
> -		size_t data_len)
> -{
> -	struct elf_note *note = (struct elf_note *)buf;
> -	note->n_namesz = strlen(name) + 1;
> -	note->n_descsz = data_len;
> -	note->n_type   = type;
> -	buf += (sizeof(*note) + 3)/4;
> -	memcpy(buf, name, note->n_namesz);
> -	buf += (note->n_namesz + 3)/4;
> -	memcpy(buf, data, data_len);
> -	buf += (data_len + 3)/4;
> -	return buf;
> -}
> -
> -static void
> -final_note(void *buf)
> -{
> -	memset(buf, 0, sizeof(struct elf_note));
> -}
> -
> -extern void ia64_dump_cpu_regs(void *);
> -
> -static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
> -
>  void
> -crash_save_this_cpu(void)
> +ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
>  {
> -	void *buf;
>  	unsigned long cfm, sof, sol;
> -
> -	int cpu = smp_processor_id();
> -	struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
> -
> -	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
> -	memset(prstatus, 0, sizeof(*prstatus));
> -	prstatus->pr_pid = current->pid;
> +	elf_greg_t *dst = (elf_greg_t *)elfregs;

There was a concern about struct elf_prstatus is so big on IA64 that it better not to put it on stack, consider crash happen with a deep stack..., So I put the structure into percpu data.

With this patch, it fallbacks to stack.

Thanks
Zou Nan hai

> 
>  	ia64_dump_cpu_regs(dst);
>  	cfm = dst[43];
> @@ -70,13 +37,6 @@
>  	sof = cfm & 0x7f;
>  	dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
>  			sof - sol);
> -
> -	buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
> -	if (!buf)
> -		return;
> -	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
> -			sizeof(*prstatus));
> -	final_note(buf);
>  }
> 
>  #ifdef CONFIG_SMP
> @@ -134,7 +94,7 @@
>  	int cpuid;
>  	local_irq_disable();
>  	cpuid = smp_processor_id();
> -	crash_save_this_cpu();
> +	crash_save_cpu(NULL, smp_processor_id());
>  	current->thread.ksp = (__u64)info->sw - 16;
>  	atomic_inc(&kdump_cpu_frozen);
>  	kdump_status[cpuid] = 1;
> Index: linux-2.6/include/asm/kexec.h
> =================================> --- linux-2.6.orig/include/asm-ia64/kexec.h	2007-04-16
> 16:13:57.000000000 +0900
> +++ linux-2.6/include/asm-ia64/kexec.h	2007-04-16 16:14:52.000000000
> +0900
> @@ -19,6 +19,9 @@
>                  flush_icache_range(page_addr, page_addr + PAGE_SIZE); \
>          } while(0)
> 
> +#define kexec_elf_core_copy_regs(elfregs, regs) \
> +	ia64_kexec_elf_core_copy_regs(elfregs, regs)
> +
>  extern struct kimage *ia64_kimage;
>  extern const unsigned int relocate_new_kernel_size;
>  extern void relocate_new_kernel(unsigned long, unsigned long,
> @@ -32,7 +35,9 @@
>  extern void kdump_smp_send_stop(void);
>  extern void kdump_smp_send_init(void);
>  extern void kexec_disable_iosapic(void);
> -extern void crash_save_this_cpu(void);
> +extern void ia64_dump_cpu_regs(void *);
> +extern void ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs,
> +					  struct pt_regs *regs);
>  struct rsvd_region;
>  extern unsigned long kdump_find_rsvd_region(unsigned long size,
>  		struct rsvd_region *rsvd_regions, int n);
> Index: linux-2.6/include/linux/kexec.h
> =================================> --- linux-2.6.orig/include/linux/kexec.h	2007-04-16 16:13:57.000000000
> +0900
> +++ linux-2.6/include/linux/kexec.h	2007-04-16 16:14:52.000000000 +0900
> @@ -128,6 +128,11 @@
>  #define kexec_flush_icache_page(page)
>  #endif
> 
> +#ifndef kexec_elf_core_copy_regs
> +#define kexec_elf_core_copy_regs(elfregs, regs) \
> +	elf_core_copy_regs(elfregs, regs)
> +#endif
> +
>  #define KEXEC_ON_CRASH  0x00000001
>  #define KEXEC_ARCH_MASK 0xffff0000
> 
> Index: linux-2.6/kernel/kexec.c
> =================================> --- linux-2.6.orig/kernel/kexec.c	2007-04-16 16:13:57.000000000 +0900
> +++ linux-2.6/kernel/kexec.c	2007-04-16 16:14:52.000000000 +0900
> @@ -1117,7 +1117,7 @@
>  		return;
>  	memset(&prstatus, 0, sizeof(prstatus));
>  	prstatus.pr_pid = current->pid;
> -	elf_core_copy_regs(&prstatus.pr_reg, regs);
> +	kexec_elf_core_copy_regs(&prstatus.pr_reg, regs);
>  	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
>  		      	      &prstatus, sizeof(prstatus));
>  	final_note(buf);
> Index: linux-2.6/arch/ia64/kernel/machine_kexec.c
> =================================> --- linux-2.6.orig/arch/ia64/kernel/machine_kexec.c	2007-04-16
> 16:11:23.000000000 +0900
> +++ linux-2.6/arch/ia64/kernel/machine_kexec.c	2007-04-16
> 16:14:52.000000000 +0900
> @@ -84,7 +84,7 @@
> 
>  	BUG_ON(!image);
>  	if (image->type = KEXEC_TYPE_CRASH) {
> -		crash_save_this_cpu();
> +		crash_save_cpu(NULL, smp_processor_id());
>  		current->thread.ksp = (__u64)info->sw - 16;
>  	}
> 

Re: [PATCH] kexec/kdump: Use generic elf code on ia64

[Simon Horman]

On Fri, Apr 20, 2007 at 01:15:34AM +0800, Zou, Nanhai wrote:
> 
> > -----Original Message-----
> > From: Simon Horman [mailto:horms@verge.net.au]
> > Sent: 2007年4月16日 16:21
> > To: fastboot@lists.osdl.org; linux-ia64@vger.kernel.org
> > Cc: Vivek Goyal; Luck, Tony; Zou, Nanhai
> > Subject: Re: [PATCH] kexec/kdump: Use generic elf code on ia64

[snip]

> > -crash_save_this_cpu(void)
> > +ia64_kexec_elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
> >  {
> > -	void *buf;
> >  	unsigned long cfm, sof, sol;
> > -
> > -	int cpu = smp_processor_id();
> > -	struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);
> > -
> > -	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
> > -	memset(prstatus, 0, sizeof(*prstatus));
> > -	prstatus->pr_pid = current->pid;
> > +	elf_greg_t *dst = (elf_greg_t *)elfregs;
> 
> There was a concern about struct elf_prstatus is so big on IA64 that it better not to put it on stack, consider crash happen with a deep stack..., So I put the structure into percpu data.
> 
> With this patch, it fallbacks to stack.

Thanks, I was wondering why was per_cpu rather than on the stack.
I'll rework things a bit so per_cpu data is used once again.

[snip]

-- 
Horms
  H: http://www.vergenet.net/~horms/
  W: http://www.valinux.co.jp/en/