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SubjectRe: [PATCH 2/4] kprobes/x86: use instruction_pointer and instruction_pointer_set
On Mon, 19 Aug 2019 11:36:48 +0000
Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:

> This is to make the kprobe_ftrace_handler() common, so we can move it
> to common code in next patch.
>

BTW, this patch looks good, without next patch. Could you update the
patch description and resend it with my Ack?

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you,

> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
> arch/x86/kernel/kprobes/ftrace.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
> index 681a4b36e9bb..c2ad0b9259ca 100644
> --- a/arch/x86/kernel/kprobes/ftrace.c
> +++ b/arch/x86/kernel/kprobes/ftrace.c
> @@ -28,9 +28,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> if (kprobe_running()) {
> kprobes_inc_nmissed_count(p);
> } else {
> - unsigned long orig_ip = regs->ip;
> + unsigned long orig_ip = instruction_pointer(regs);
> /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
> - regs->ip = ip + sizeof(kprobe_opcode_t);
> + instruction_pointer_set(regs, ip + sizeof(kprobe_opcode_t));
>
> __this_cpu_write(current_kprobe, p);
> kcb->kprobe_status = KPROBE_HIT_ACTIVE;
> @@ -39,12 +39,13 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> * Emulate singlestep (and also recover regs->ip)
> * as if there is a 5byte nop
> */
> - regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
> + instruction_pointer_set(regs,
> + (unsigned long)p->addr + MCOUNT_INSN_SIZE);
> if (unlikely(p->post_handler)) {
> kcb->kprobe_status = KPROBE_HIT_SSDONE;
> p->post_handler(p, regs, 0);
> }
> - regs->ip = orig_ip;
> + instruction_pointer_set(regs, orig_ip);
> }
> /*
> * If pre_handler returns !0, it changes regs->ip. We have to
> --
> 2.23.0.rc1
>


--
Masami Hiramatsu <mhiramat@kernel.org>

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