2 files changed, 39 insertions, 2 deletions

diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index 55250593d8c9..0803d3858af1 100644
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -41,6 +41,41 @@
 #define PF_RSVD (1<<3)
 #define PF_INSTR        (1<<4)
 
+#ifdef CONFIG_KPROBES
+ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
+
+/* Hook to register for page fault notifications */
+int register_page_fault_notifier(struct notifier_block *nb)
+{
+        vmalloc_sync_all();
+        return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
+}
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+        return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
+}
+
+static inline int notify_page_fault(enum die_val val, const char *str,
+                        struct pt_regs *regs, long err, int trap, int sig)
+{
+        struct die_args args = {
+                .regs = regs,
+                .str = str,
+                .err = err,
+                .trapnr = trap,
+                .signr = sig
+        };
+        return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+}
+#else
+static inline int notify_page_fault(enum die_val val, const char *str,
+                        struct pt_regs *regs, long err, int trap, int sig)
+{
+        return NOTIFY_DONE;
+}
+#endif
+
 void bust_spinlocks(int yes)
 {
         int loglevel_save = console_loglevel;
@@ -348,7 +383,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
                         if (vmalloc_fault(address) >= 0)
                                 return;
                 }
-                if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+                if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
                                                 SIGSEGV) == NOTIFY_STOP)
                         return;
                 /*
@@ -358,7 +393,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
                 goto bad_area_nosemaphore;
         }
 
-        if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+        if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
                                         SIGSEGV) == NOTIFY_STOP)
                 return;
 
diff --git a/include/asm-x86_64/kdebug.h b/include/asm-x86_64/kdebug.h
index cf795631d9b4..cd52c7f33bca 100644
--- a/include/asm-x86_64/kdebug.h
+++ b/include/asm-x86_64/kdebug.h
@@ -15,6 +15,8 @@ struct die_args {
 
 extern int register_die_notifier(struct notifier_block *);
 extern int unregister_die_notifier(struct notifier_block *);
+extern int register_page_fault_notifier(struct notifier_block *);
+extern int unregister_page_fault_notifier(struct notifier_block *);
 extern struct atomic_notifier_head die_chain;
 
 /* Grossly misnamed. */