linux-kernel - [PATCH] kprobes/x86: use instruction_pointer and instruction_pointer

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Message-ID: <20190821134244.2e0f248c@xhacker.debian>
Date:   Wed, 21 Aug 2019 05:54:00 +0000
From:   Jisheng Zhang <Jisheng.Zhang@...aptics.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Masami Hiramatsu <mhiramat@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: [PATCH] kprobes/x86: use instruction_pointer and
 instruction_pointer_set

Use an arch-independent way to get/set the instruction pointer, we can
make the x86 kprobe_ftrace_handler() more common.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 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