Merge branch 'next/drivers' into HEAD

[deliverable/linux.git] / arch / x86 / kernel / kprobes.c

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index e2f751efb7b1ef25ce9329a49128a48c1dcf9c3f..57916c0d3cf6c21ff622a57077e56dec52469d9e 100644 (file)
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -541,6 +541,23 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
        return 1;
 }
 
+#ifdef KPROBES_CAN_USE_FTRACE
+static void __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+                                     struct kprobe_ctlblk *kcb)
+{
+       /*
+        * Emulate singlestep (and also recover regs->ip)
+        * as if there is a 5byte nop
+        */
+       regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
+       if (unlikely(p->post_handler)) {
+               kcb->kprobe_status = KPROBE_HIT_SSDONE;
+               p->post_handler(p, regs, 0);
+       }
+       __this_cpu_write(current_kprobe, NULL);
+}
+#endif
+
 /*
  * Interrupts are disabled on entry as trap3 is an interrupt gate and they
  * remain disabled throughout this function.
@@ -599,6 +616,12 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
        } else if (kprobe_running()) {
                p = __this_cpu_read(current_kprobe);
                if (p->break_handler && p->break_handler(p, regs)) {
+#ifdef KPROBES_CAN_USE_FTRACE
+                       if (kprobe_ftrace(p)) {
+                               skip_singlestep(p, regs, kcb);
+                               return 1;
+                       }
+#endif
                        setup_singlestep(p, regs, kcb, 0);
                        return 1;
                }
@@ -1052,6 +1075,50 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
        return 0;
 }
 
+#ifdef KPROBES_CAN_USE_FTRACE
+/* Ftrace callback handler for kprobes */
+void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+                                    struct ftrace_ops *ops, struct pt_regs *regs)
+{
+       struct kprobe *p;
+       struct kprobe_ctlblk *kcb;
+       unsigned long flags;
+
+       /* Disable irq for emulating a breakpoint and avoiding preempt */
+       local_irq_save(flags);
+
+       p = get_kprobe((kprobe_opcode_t *)ip);
+       if (unlikely(!p) || kprobe_disabled(p))
+               goto end;
+
+       kcb = get_kprobe_ctlblk();
+       if (kprobe_running()) {
+               kprobes_inc_nmissed_count(p);
+       } else {
+               /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
+               regs->ip = ip + sizeof(kprobe_opcode_t);
+
+               __this_cpu_write(current_kprobe, p);
+               kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+               if (!p->pre_handler || !p->pre_handler(p, regs))
+                       skip_singlestep(p, regs, kcb);
+               /*
+                * If pre_handler returns !0, it sets regs->ip and
+                * resets current kprobe.
+                */
+       }
+end:
+       local_irq_restore(flags);
+}
+
+int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+       p->ainsn.insn = NULL;
+       p->ainsn.boostable = -1;
+       return 0;
+}
+#endif
+
 int __init arch_init_kprobes(void)
 {
        return arch_init_optprobes();