x86: move deeply indented code to reenter_kprobe

Move some deeply indented code related to re-entrance processing
from kprobe_handler() to reenter_kprobe().

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 7dd9186..4e33329 100644 (file)
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -432,14 +432,32 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
  * within the handler. We save the original kprobes variables and just single
  * step on the instruction of the new probe without calling any user handlers.
  */
-static void __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
-                                    struct kprobe_ctlblk *kcb)
+static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
+                                   struct kprobe_ctlblk *kcb)
 {
+       if (kcb->kprobe_status == KPROBE_HIT_SS &&
+           *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
+               regs->flags &= ~X86_EFLAGS_TF;
+               regs->flags |= kcb->kprobe_saved_flags;
+               return 0;
+#ifdef CONFIG_X86_64
+       } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
+               /* TODO: Provide re-entrancy from post_kprobes_handler() and
+                * avoid exception stack corruption while single-stepping on
+                * the instruction of the new probe.
+                */
+               arch_disarm_kprobe(p);
+               regs->ip = (unsigned long)p->addr;
+               reset_current_kprobe();
+               return 1;
+#endif
+       }
        save_previous_kprobe(kcb);
        set_current_kprobe(p, regs, kcb);
        kprobes_inc_nmissed_count(p);
        prepare_singlestep(p, regs);
        kcb->kprobe_status = KPROBE_REENTER;
+       return 1;
 }
 
 /*
@@ -466,27 +484,9 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
        if (kprobe_running()) {
                p = get_kprobe(addr);
                if (p) {
-                       if (kcb->kprobe_status == KPROBE_HIT_SS &&
-                               *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
-                               regs->flags &= ~X86_EFLAGS_TF;
-                               regs->flags |= kcb->kprobe_saved_flags;
-                               goto no_kprobe;
-#ifdef CONFIG_X86_64
-                       } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
-                               /* TODO: Provide re-entrancy from
-                                * post_kprobes_handler() and avoid exception
-                                * stack corruption while single-stepping on
-                                * the instruction of the new probe.
-                                */
-                               arch_disarm_kprobe(p);
-                               regs->ip = (unsigned long)p->addr;
-                               reset_current_kprobe();
-                               ret = 1;
-                               goto no_kprobe;
-#endif
-                       }
-                       reenter_kprobe(p, regs, kcb);
-                       return 1;
+                       ret = reenter_kprobe(p, regs, kcb);
+                       if (kcb->kprobe_status == KPROBE_REENTER)
+                               return 1;
                } else {
                        if (*addr != BREAKPOINT_INSTRUCTION) {
                        /* The breakpoint instruction was removed by