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Subject[PATCH 2/4] x86/kprobes: Fix frame pointer annotations
The kprobe trampolines have a FRAME_POINTER annotation that makes no
sense. It marks the frame in the middle of pt_regs, at the place of
saving BP.

Change it to mark the pt_regs frame as per the ENCODE_FRAME_POINTER
from the respective entry_*.S.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/kprobes/common.h | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)

--- a/arch/x86/kernel/kprobes/common.h
+++ b/arch/x86/kernel/kprobes/common.h
@@ -6,14 +6,15 @@

#include <asm/asm.h>

+#ifdef CONFIG_X86_64
+
#ifdef CONFIG_FRAME_POINTER
-# define SAVE_RBP_STRING " push %" _ASM_BP "\n" \
- " mov %" _ASM_SP ", %" _ASM_BP "\n"
+#define ENCODE_FRAME_POINTER \
+ " leaq 1(%rsp), %rbp\n"
#else
-# define SAVE_RBP_STRING " push %" _ASM_BP "\n"
+#define ENCODE_FRAME_POINTER
#endif

-#ifdef CONFIG_X86_64
#define SAVE_REGS_STRING \
/* Skip cs, ip, orig_ax. */ \
" subq $24, %rsp\n" \
@@ -27,11 +28,13 @@
" pushq %r10\n" \
" pushq %r11\n" \
" pushq %rbx\n" \
- SAVE_RBP_STRING \
+ " pushq %rbp\n" \
" pushq %r12\n" \
" pushq %r13\n" \
" pushq %r14\n" \
- " pushq %r15\n"
+ " pushq %r15\n" \
+ ENCODE_FRAME_POINTER
+
#define RESTORE_REGS_STRING \
" popq %r15\n" \
" popq %r14\n" \
@@ -51,19 +54,30 @@
/* Skip orig_ax, ip, cs */ \
" addq $24, %rsp\n"
#else
+
+#ifdef CONFIG_FRAME_POINTER
+#define ENCODE_FRAME_POINTER \
+ " movl %esp, %ebp\n" \
+ " andl $0x7fffffff, %ebp\n"
+#else
+#define ENCODE_FRAME_POINTER
+#endif
+
#define SAVE_REGS_STRING \
/* Skip cs, ip, orig_ax and gs. */ \
- " subl $16, %esp\n" \
+ " subl $4*4, %esp\n" \
" pushl %fs\n" \
" pushl %es\n" \
" pushl %ds\n" \
" pushl %eax\n" \
- SAVE_RBP_STRING \
+ " pushl %ebp\n" \
" pushl %edi\n" \
" pushl %esi\n" \
" pushl %edx\n" \
" pushl %ecx\n" \
- " pushl %ebx\n"
+ " pushl %ebx\n" \
+ ENCODE_FRAME_POINTER
+
#define RESTORE_REGS_STRING \
" popl %ebx\n" \
" popl %ecx\n" \

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