diff options
Diffstat (limited to 'arch/powerpc/kernel/kprobes.c')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 23545a2f51f..4ba2af12545 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -34,6 +34,13 @@ #include <asm/cacheflush.h> #include <asm/sstep.h> #include <asm/uaccess.h> +#include <asm/system.h> + +#ifdef CONFIG_BOOKE +#define MSR_SINGLESTEP (MSR_DE) +#else +#define MSR_SINGLESTEP (MSR_SE) +#endif DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); @@ -53,7 +60,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) ret = -EINVAL; } - /* insn must be on a special executable page on ppc64 */ + /* insn must be on a special executable page on ppc64. This is + * not explicitly required on ppc32 (right now), but it doesn't hurt */ if (!ret) { p->ainsn.insn = get_insn_slot(); if (!p->ainsn.insn) @@ -95,7 +103,16 @@ void __kprobes arch_remove_kprobe(struct kprobe *p) static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) { - regs->msr |= MSR_SE; + /* 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_SINGLESTEP; +#ifdef CONFIG_BOOKE + regs->msr &= ~MSR_CE; + mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); +#endif /* * On powerpc we should single step on the original @@ -158,7 +175,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) kprobe_opcode_t insn = *p->ainsn.insn; if (kcb->kprobe_status == KPROBE_HIT_SS && is_trap(insn)) { - regs->msr &= ~MSR_SE; + /* Turn off 'trace' bits */ + regs->msr &= ~MSR_SINGLESTEP; regs->msr |= kcb->kprobe_saved_msr; goto no_kprobe; } @@ -376,6 +394,10 @@ 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); @@ -395,10 +417,10 @@ out: /* * if somebody else is singlestepping across a probe point, msr - * will have SE set, in which case, continue the remaining processing + * will have DE/SE set, in which case, continue the remaining processing * of do_debug, as if this is not a probe hit. */ - if (regs->msr & MSR_SE) + if (regs->msr & MSR_SINGLESTEP) return 0; return 1; @@ -421,7 +443,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) * normal page fault. */ regs->nip = (unsigned long)cur->addr; - regs->msr &= ~MSR_SE; + regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */ regs->msr |= kcb->kprobe_saved_msr; if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); |