[PATCH] x86: Rename stack_pointer to kernel_trap_sp

Harvey Harrison
2008-01-18T04:29:06Z

Choose a less generic name for such a special case. Add
a comment explaining the odd use in X86_32.

Change the one user of stack_pointer.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
arch/x86/oprofile/backtrace.c | 2 +-
include/asm-x86/ptrace.h | 8 +++++++-
2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 0ca4815..e2095cb 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -77,7 +77,7 @@ void
x86_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_head *head = (struct frame_head *)frame_pointer(regs);
- unsigned long stack = stack_pointer(regs);
+ unsigned long stack = kernel_trap_sp(regs);

if (!user_mode_vm(regs)) {
if (depth)
diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h
index 79d5b8f..d9e04b4 100644
--- a/include/asm-x86/ptrace.h
+++ b/include/asm-x86/ptrace.h
@@ -182,7 +182,13 @@ static inline int v8086_mode(struct pt_regs *regs)
#endif
}

-static inline unsigned long stack_pointer(struct pt_regs *regs)
+/*
+ * X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode
+ * when it traps. So regs will be the current sp.
+ *
+ * This is valid only for kernel mode traps.
+ */
+static inline unsigned long kernel_trap_sp(struct pt_regs *regs)
{
#ifdef CONFIG_X86_32
return (unsigned long)regs;
--
1.5.4.rc2.1164.g6451