From 91fc862c613ab7a0ef6b0b7755c33619127f4e5a Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 14 Feb 2017 00:04:48 +0900 Subject: [PATCH] arm: kprobes: Skip single-stepping in recursing path if possible Kprobes/arm skips single-stepping (moreover handling the event) if the conditional instruction must not be executed. This also apply the rule when we hit the recursing kprobe, so that kprobe does not count nmissed up in that case. Signed-off-by: Masami Hiramatsu Signed-off-by: Jon Medhurst --- arch/arm/probes/kprobes/core.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 35148b46c4f5..269f66e66ff5 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -266,7 +266,15 @@ void __kprobes kprobe_handler(struct pt_regs *regs) #endif if (p) { - if (cur) { + if (!p->ainsn.insn_check_cc(regs->ARM_cpsr)) { + /* + * Probe hit but conditional execution check failed, + * so just skip the instruction and continue as if + * nothing had happened. + * In this case, we can skip recursing check too. + */ + singlestep_skip(p, regs); + } else if (cur) { /* Kprobe is pending, so we're recursing. */ switch (kcb->kprobe_status) { case KPROBE_HIT_ACTIVE: @@ -289,7 +297,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs) /* impossible cases */ BUG(); } - } else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) { + } else { /* Probe hit and conditional execution check ok. */ set_current_kprobe(p); kcb->kprobe_status = KPROBE_HIT_ACTIVE; @@ -310,13 +318,6 @@ void __kprobes kprobe_handler(struct pt_regs *regs) } reset_current_kprobe(); } - } else { - /* - * Probe hit but conditional execution check failed, - * so just skip the instruction and continue as if - * nothing had happened. - */ - singlestep_skip(p, regs); } } else if (cur) { /* We probably hit a jprobe. Call its break handler. */ -- 2.20.1