sh: Add die chain notifiers.

Add the atomic die chains in, kprobes needs these.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 37 insertions, 2 deletions

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index fa5d7f0b9f18..0ecc117cade4 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -2,7 +2,7 @@
  * Page fault handler for SH with an MMU.
  *
  *  Copyright (C) 1999  Niibe Yutaka
- *  Copyright (C) 2003  Paul Mundt
+ *  Copyright (C) 2003 - 2007  Paul Mundt
  *
  *  Based on linux/arch/i386/mm/fault.c:
  *   Copyright (C) 1995  Linus Torvalds
@@ -15,12 +15,42 @@
 #include <linux/mm.h>
 #include <linux/hardirq.h>
 #include <linux/kprobes.h>
+#include <asm/kdebug.h>
 #include <asm/system.h>
 #include <asm/mmu_context.h>
 #include <asm/tlbflush.h>
 #include <asm/kgdb.h>
 
-extern void die(const char *,struct pt_regs *,long);
+#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)
+{
+        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, struct pt_regs *regs,
+                                    int trap, int sig)
+{
+        struct die_args args = {
+                .regs = regs,
+                .trapnr = trap,
+        };
+        return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+}
+#else
+static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
+                                    int trap, int sig)
+{
+        return NOTIFY_DONE;
+}
+#endif
 
 /*
  * This routine handles page faults.  It determines the address,
@@ -39,6 +69,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
         siginfo_t info;
 
         trace_hardirqs_on();
+
+        if (notify_page_fault(DIE_PAGE_FAULT, regs,
+                              writeaccess, SIGSEGV) == NOTIFY_STOP)
+                return;
+
         local_irq_enable();
 
 #ifdef CONFIG_SH_KGDB