kprobes/x86: Call out into INT3 handler directly instead of using notifier

[karo-tx-linux.git] / arch / x86 / kernel / alternative.c

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 5d8782ee3dd74bfa00b1821486a8b7ca59f89a0e..15e8563e5c244e0712c9696a3367067044a300b3 100644 (file)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -605,26 +605,24 @@ static void do_sync_core(void *info)
 static bool bp_patching_in_progress;
 static void *bp_int3_handler, *bp_int3_addr;
 
-static int int3_notify(struct notifier_block *self, unsigned long val, void *data)
+int poke_int3_handler(struct pt_regs *regs)
 {
-       struct die_args *args = data;
-
        /* bp_patching_in_progress */
        smp_rmb();
 
        if (likely(!bp_patching_in_progress))
-               return NOTIFY_DONE;
+               return 0;
 
-       /* we are not interested in non-int3 faults and ring > 0 faults */
-       if (val != DIE_INT3 || !args->regs || user_mode_vm(args->regs)
-                           || args->regs->ip != (unsigned long)bp_int3_addr)
-               return NOTIFY_DONE;
+       if (user_mode_vm(regs) || regs->ip != (unsigned long)bp_int3_addr)
+               return 0;
 
        /* set up the specified breakpoint handler */
-       args->regs->ip = (unsigned long) bp_int3_handler;
+       regs->ip = (unsigned long) bp_int3_handler;
+
+       return 1;
 
-       return NOTIFY_STOP;
 }
+
 /**
  * text_poke_bp() -- update instructions on live kernel on SMP
  * @addr:      address to patch
@@ -689,16 +687,3 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
        return addr;
 }
 
-/* this one needs to run before anything else handles it as a
- * regular exception */
-static struct notifier_block int3_nb = {
-       .priority = 0x7fffffff,
-       .notifier_call = int3_notify
-};
-
-static int __init int3_init(void)
-{
-       return register_die_notifier(&int3_nb);
-}
-
-arch_initcall(int3_init);