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authorH. Peter Anvin <hpa@zytor.com>2009-10-12 14:14:10 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-10-12 14:19:35 -0700
commit98272ed0d2e6509fe7dc571e77956c99bf653bb6 (patch)
treedb4cd56e10c0b9ce103d8aa3b4746ec805164cd0
parent5ca6c0ca5dbf105d7b0ffdae2289519982189730 (diff)
downloadop-kernel-dev-98272ed0d2e6509fe7dc571e77956c99bf653bb6.zip
op-kernel-dev-98272ed0d2e6509fe7dc571e77956c99bf653bb6.tar.gz
x86: use kernel_stack_pointer() in kprobes.c
The way to obtain a kernel-mode stack pointer from a struct pt_regs in 32-bit mode is "subtle": the stack doesn't actually contain the stack pointer, but rather the location where it would have been marks the actual previous stack frame. For clarity, use kernel_stack_pointer() instead of coding this weirdness explicitly. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com>
-rw-r--r--arch/x86/kernel/kprobes.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 7b5169d..2ee4fa3 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -60,19 +60,7 @@ void jprobe_return_end(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
-#ifdef CONFIG_X86_64
-#define stack_addr(regs) ((unsigned long *)regs->sp)
-#else
-/*
- * "&regs->sp" looks wrong, but it's correct for x86_32. x86_32 CPUs
- * don't save the ss and esp registers if the CPU is already in kernel
- * mode when it traps. So for kprobes, regs->sp and regs->ss are not
- * the [nonexistent] saved stack pointer and ss register, but rather
- * the top 8 bytes of the pre-int3 stack. So &regs->sp happens to
- * point to the top of the pre-int3 stack.
- */
-#define stack_addr(regs) ((unsigned long *)&regs->sp)
-#endif
+#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
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