From b76e59d1fb086c2fdac5d243e09786d6581f2026 Mon Sep 17 00:00:00 2001 From: Kumar Gala Date: Thu, 26 Jun 2008 01:57:58 -0500 Subject: [PATCH] powerpc/kprobes: Some minor fixes * Mark __flush_icache_range as a function that can't be probed since its used by the kprobe code. * Fix an issue with single stepping and async exceptions. We need to ensure that we dont get an async exception (external, decrementer, etc) while we are attempting to single step the probe point. Added a check to ensure we only handle a single step if its really intended for the instruction in question. Signed-off-by: Kumar Gala --- arch/powerpc/kernel/kprobes.c | 9 +++++++++ arch/powerpc/kernel/misc_32.S | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 23545a2f51f3..74693d91731f 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -95,6 +95,11 @@ void __kprobes arch_remove_kprobe(struct kprobe *p) static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { + /* We turn off async exceptions to ensure that the single step will + * be for the instruction we have the kprobe on, if we dont its + * possible we'd get the single step reported for an exception handler + * like Decrementer or External Interrupt */ + regs->msr &= ~MSR_EE; regs->msr |= MSR_SE; /* @@ -376,6 +381,10 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs) if (!cur) return 0; + /* make sure we got here for instruction we have a kprobe on */ + if (((unsigned long)cur->ainsn.insn + 4) != regs->nip) + return 0; + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { kcb->kprobe_status = KPROBE_HIT_SSDONE; cur->post_handler(cur, regs, 0); diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index 89aaaa6f3561..6321ae36f729 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -489,7 +489,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE) * * flush_icache_range(unsigned long start, unsigned long stop) */ -_GLOBAL(__flush_icache_range) +_KPROBE(__flush_icache_range) BEGIN_FTR_SECTION blr /* for 601, do nothing */ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) -- 2.20.1