[PATCH -tip v5 08/12] arm: kprobes: Make a space for regs->ARM_pc at kretprobe_trampoline

Masami Hiramatsu
2021-03-26T12:30:00Z

Change kretprobe_trampoline to make a space for regs->ARM_pc so that
kretprobe_trampoline_handler can call instruction_pointer_set()
safely.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm/probes/kprobes/core.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 1782b41df095..5f3c2b42787f 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -397,11 +397,13 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
void __naked __kprobes kretprobe_trampoline(void)
{
__asm__ __volatile__ (
+ "sub sp, sp, #16 \n\t"
"stmdb sp!, {r0 - r11} \n\t"
"mov r0, sp \n\t"
"bl trampoline_handler \n\t"
"mov lr, r0 \n\t"
"ldmia sp!, {r0 - r11} \n\t"
+ "add sp, sp, #16 \n\t"
#ifdef CONFIG_THUMB2_KERNEL
"bx lr \n\t"
#else