[PATCH] x86_64: Save original IST values for checking stack addresses
The values in init_tss.ist[] can change when an IST event occurs. Save
the original IST values for checking stack addresses when debugging or
doing stack traces.
Signed-off-by: Keith Owens <kaos@ocs.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/init_task.c b/arch/x86_64/kernel/init_task.c
index ce31d90..3dc5854 100644
--- a/arch/x86_64/kernel/init_task.c
+++ b/arch/x86_64/kernel/init_task.c
@@ -46,4 +46,9 @@
*/
DEFINE_PER_CPU(struct tss_struct, init_tss) ____cacheline_internodealigned_in_smp = INIT_TSS;
+/* Copies of the original ist values from the tss are only accessed during
+ * debugging, no special alignment required.
+ */
+DEFINE_PER_CPU(struct orig_ist, orig_ist);
+
#define ALIGN_TO_4K __attribute__((section(".data.init_task")))
diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c
index 6fe58a6..417de56 100644
--- a/arch/x86_64/kernel/setup64.c
+++ b/arch/x86_64/kernel/setup64.c
@@ -189,6 +189,7 @@
{
int cpu = stack_smp_processor_id();
struct tss_struct *t = &per_cpu(init_tss, cpu);
+ struct orig_ist *orig_ist = &per_cpu(orig_ist, cpu);
unsigned long v;
char *estacks = NULL;
struct task_struct *me;
@@ -256,7 +257,7 @@
estacks += EXCEPTION_STKSZ;
break;
}
- t->ist[v] = (unsigned long)estacks;
+ orig_ist->ist[v] = t->ist[v] = (unsigned long)estacks;
}
t->io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index 5e00af5..b124977 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -178,7 +178,7 @@
break;
#endif
default:
- end = per_cpu(init_tss, cpu).ist[k];
+ end = per_cpu(orig_ist, cpu).ist[k];
break;
}
/*
diff --git a/include/asm-x86_64/processor.h b/include/asm-x86_64/processor.h
index 3b3c121..de9c314 100644
--- a/include/asm-x86_64/processor.h
+++ b/include/asm-x86_64/processor.h
@@ -232,8 +232,14 @@
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
} __attribute__((packed)) ____cacheline_aligned;
+
extern struct cpuinfo_x86 boot_cpu_data;
DECLARE_PER_CPU(struct tss_struct,init_tss);
+/* Save the original ist values for checking stack pointers during debugging */
+struct orig_ist {
+ unsigned long ist[7];
+};
+DECLARE_PER_CPU(struct orig_ist, orig_ist);
#ifdef CONFIG_X86_VSMP
#define ARCH_MIN_TASKALIGN (1 << INTERNODE_CACHE_SHIFT)