The kretprobe_trampoline_holder() wrapper around kretprobe_trampoline()
isn't used anywhere and adds some unnecessary frame pointer instructions
which never execute. Instead, just make kretprobe_trampoline() a proper
ELF function.
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 57 +++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 29 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1deffe6..5b187df 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -671,38 +671,37 @@ NOKPROBE_SYMBOL(kprobe_int3_handler);
* When a retprobed function returns, this code saves registers and
* calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
-static void __used kretprobe_trampoline_holder(void)
-{
- asm volatile (
- ".global kretprobe_trampoline\n"
- "kretprobe_trampoline: \n"
+asm(
+ ".global kretprobe_trampoline\n"
+ ".type kretprobe_trampoline, @function\n"
+ "kretprobe_trampoline:\n"
#ifdef CONFIG_X86_64
- /* We don't bother saving the ss register */
- " pushq %rsp\n"
- " pushfq\n"
- SAVE_REGS_STRING
- " movq %rsp, %rdi\n"
- " call trampoline_handler\n"
- /* Replace saved sp with true return address. */
- " movq %rax, 152(%rsp)\n"
- RESTORE_REGS_STRING
- " popfq\n"
+ /* We don't bother saving the ss register */
+ " pushq %rsp\n"
+ " pushfq\n"
+ SAVE_REGS_STRING
+ " movq %rsp, %rdi\n"
+ " call trampoline_handler\n"
+ /* Replace saved sp with true return address. */
+ " movq %rax, 152(%rsp)\n"
+ RESTORE_REGS_STRING
+ " popfq\n"
#else
- " pushf\n"
- SAVE_REGS_STRING
- " movl %esp, %eax\n"
- " call trampoline_handler\n"
- /* Move flags to cs */
- " movl 56(%esp), %edx\n"
- " movl %edx, 52(%esp)\n"
- /* Replace saved flags with true return address. */
- " movl %eax, 56(%esp)\n"
- RESTORE_REGS_STRING
- " popf\n"
+ " pushf\n"
+ SAVE_REGS_STRING
+ " movl %esp, %eax\n"
+ " call trampoline_handler\n"
+ /* Move flags to cs */
+ " movl 56(%esp), %edx\n"
+ " movl %edx, 52(%esp)\n"
+ /* Replace saved flags with true return address. */
+ " movl %eax, 56(%esp)\n"
+ RESTORE_REGS_STRING
+ " popf\n"
#endif
- " ret\n");
-}
-NOKPROBE_SYMBOL(kretprobe_trampoline_holder);
+ " ret\n"
+ ".size kretprobe_trampoline, .-kretprobe_trampoline\n"
+);
NOKPROBE_SYMBOL(kretprobe_trampoline);
/*
--
2.4.3
--
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