Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH] ARM: kprobes: Make __kretprobe_trampoline as a pure asm function | Date | Tue, 15 Mar 2022 18:52:16 +0900 |
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Make __kretprobe_trampoline() as a pure asm function same as the x86 code does. Anyway, it is safe to define the symbol in the asm code instead of accessing a C symbol from the inline asm.
Without this fix, building arm kernel with GCC-11 may cause below error.
/tmp/ccIWiggX.s: Assembler messages: >> /tmp/ccIWiggX.s:22: Error: invalid literal constant: pool needs to be closer
This fixes the error reported by 0day build bot.
Reported-by: kernel test robot <lkp@intel.com> Fixes: 7e9bf33b8124 ("ARM: kprobes: Make a frame pointer on __kretprobe_trampoline") Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- arch/arm/probes/kprobes/core.c | 57 +++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 27 deletions(-)
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 4848404ba51b..51f1438456ae 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -373,43 +373,46 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, * should be enough for stacktrace from the return handler with or * without pt_regs. */ -void __naked __kprobes __kretprobe_trampoline(void) -{ - __asm__ __volatile__ ( +asm( + ".text\n" + ".global __kretprobe_trampoline\n" + ".type __kretprobe_trampoline, %function\n" + "__kretprobe_trampoline:\n" #ifdef CONFIG_FRAME_POINTER - "ldr lr, =__kretprobe_trampoline \n\t" + "ldr lr, =__kretprobe_trampoline \n\t" /* __kretprobe_trampoline makes a framepointer on pt_regs. */ #ifdef CONFIG_CC_IS_CLANG - "stmdb sp, {sp, lr, pc} \n\t" - "sub sp, sp, #12 \n\t" - /* In clang case, pt_regs->ip = lr. */ - "stmdb sp!, {r0 - r11, lr} \n\t" - /* fp points regs->r11 (fp) */ - "add fp, sp, #44 \n\t" + "stmdb sp, {sp, lr, pc} \n\t" + "sub sp, sp, #12 \n\t" + /* In clang case, pt_regs->ip = lr. */ + "stmdb sp!, {r0 - r11, lr} \n\t" + /* fp points regs->r11 (fp) */ + "add fp, sp, #44 \n\t" #else /* !CONFIG_CC_IS_CLANG */ - /* In gcc case, pt_regs->ip = fp. */ - "stmdb sp, {fp, sp, lr, pc} \n\t" - "sub sp, sp, #16 \n\t" - "stmdb sp!, {r0 - r11} \n\t" - /* fp points regs->r15 (pc) */ - "add fp, sp, #60 \n\t" + /* In gcc case, pt_regs->ip = fp. */ + "stmdb sp, {fp, sp, lr, pc} \n\t" + "sub sp, sp, #16 \n\t" + "stmdb sp!, {r0 - r11} \n\t" + /* fp points regs->r15 (pc) */ + "add fp, sp, #60 \n\t" #endif /* CONFIG_CC_IS_CLANG */ #else /* !CONFIG_FRAME_POINTER */ - "sub sp, sp, #16 \n\t" - "stmdb sp!, {r0 - r11} \n\t" + "sub sp, sp, #16 \n\t" + "stmdb sp!, {r0 - r11} \n\t" #endif /* CONFIG_FRAME_POINTER */ - "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" + "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" + "bx lr \n\t" #else - "mov pc, lr \n\t" + "mov pc, lr \n\t" #endif - : : : "memory"); -} + ".size __kretprobe_trampoline, .-__kretprobe_trampoline\n" +); +NOKPROBE_SYMBOL(__kretprobe_trampoline); /* Called from __kretprobe_trampoline */ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
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