diff options
| -rw-r--r-- | arch/ppc64/kernel/kprobes.c | 46 |
1 files changed, 38 insertions, 8 deletions
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c index 8c0920a6d03..782ce3efa2c 100644 --- a/arch/ppc64/kernel/kprobes.c +++ b/arch/ppc64/kernel/kprobes.c @@ -36,12 +36,10 @@ #include <asm/kdebug.h> #include <asm/sstep.h> -/* kprobe_status settings */ -#define KPROBE_HIT_ACTIVE 0x00000001 -#define KPROBE_HIT_SS 0x00000002 - static struct kprobe *current_kprobe; static unsigned long kprobe_status, kprobe_saved_msr; +static struct kprobe *kprobe_prev; +static unsigned long kprobe_status_prev, kprobe_saved_msr_prev; static struct pt_regs jprobe_saved_regs; int arch_prepare_kprobe(struct kprobe *p) @@ -93,6 +91,20 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->nip = (unsigned long)&p->ainsn.insn; } +static inline void save_previous_kprobe(void) +{ + kprobe_prev = current_kprobe; + kprobe_status_prev = kprobe_status; + kprobe_saved_msr_prev = kprobe_saved_msr; +} + +static inline void restore_previous_kprobe(void) +{ + current_kprobe = kprobe_prev; + kprobe_status = kprobe_status_prev; + kprobe_saved_msr = kprobe_saved_msr_prev; +} + static inline int kprobe_handler(struct pt_regs *regs) { struct kprobe *p; @@ -111,9 +123,19 @@ static inline int kprobe_handler(struct pt_regs *regs) unlock_kprobes(); goto no_kprobe; } - arch_disarm_kprobe(p); - regs->nip = (unsigned long)p->addr; - ret = 1; + /* We have reentered the kprobe_handler(), since + * another probe was hit while within the handler. + * We here save the original kprobes variables and + * just single step on the instruction of the new probe + * without calling any user handlers. + */ + save_previous_kprobe(); + current_kprobe = p; + kprobe_saved_msr = regs->msr; + p->nmissed++; + prepare_singlestep(p, regs); + kprobe_status = KPROBE_REENTER; + return 1; } else { p = current_kprobe; if (p->break_handler && p->break_handler(p, regs)) { @@ -195,13 +217,21 @@ static inline int post_kprobe_handler(struct pt_regs *regs) if (!kprobe_running()) return 0; - if (current_kprobe->post_handler) + if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) { + kprobe_status = KPROBE_HIT_SSDONE; current_kprobe->post_handler(current_kprobe, regs, 0); + } resume_execution(current_kprobe, regs); regs->msr |= kprobe_saved_msr; + /*Restore back the original saved kprobes variables and continue. */ + if (kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(); + goto out; + } unlock_kprobes(); +out: preempt_enable_no_resched(); /* |