diff options
Diffstat (limited to 'arch/powerpc/kernel/kprobes-ftrace.c')
| -rw-r--r-- | arch/powerpc/kernel/kprobes-ftrace.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c index 6c089d9757c9..7a1f99f1b47f 100644 --- a/arch/powerpc/kernel/kprobes-ftrace.c +++ b/arch/powerpc/kernel/kprobes-ftrace.c @@ -25,6 +25,21 @@ #include <linux/preempt.h> #include <linux/ftrace.h> +/* + * This is called from ftrace code after invoking registered handlers to + * disambiguate regs->nip changes done by jprobes and livepatch. We check if + * there is an active jprobe at the provided address (mcount location). + */ +int __is_active_jprobe(unsigned long addr) +{ + if (!preemptible()) { + struct kprobe *p = raw_cpu_read(current_kprobe); + return (p && (unsigned long)p->addr == addr) ? 1 : 0; + } + + return 0; +} + static nokprobe_inline int __skip_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb, unsigned long orig_nip) @@ -60,11 +75,8 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, { struct kprobe *p; struct kprobe_ctlblk *kcb; - unsigned long flags; - /* Disable irq for emulating a breakpoint and avoiding preempt */ - local_irq_save(flags); - hard_irq_disable(); + preempt_disable(); p = get_kprobe((kprobe_opcode_t *)nip); if (unlikely(!p) || kprobe_disabled(p)) @@ -86,13 +98,17 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, kcb->kprobe_status = KPROBE_HIT_ACTIVE; if (!p->pre_handler || !p->pre_handler(p, regs)) __skip_singlestep(p, regs, kcb, orig_nip); - /* - * If pre_handler returns !0, it sets regs->nip and - * resets current kprobe. - */ + else { + /* + * If pre_handler returns !0, it sets regs->nip and + * resets current kprobe. In this case, we should not + * re-enable preemption. + */ + return; + } } end: - local_irq_restore(flags); + preempt_enable_no_resched(); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); |