[IA64] optimize pagefaults a little

Get rid of the notifier list and call the kprobes code directly
if compiled in.  This mirrors the changes that recently went
into powerpc, s390 and sparc64.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 14 insertions, 27 deletions

diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 21658e02116c..b87f785c2416 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -19,36 +19,24 @@
 extern void die (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)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
 {
-        return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+        int ret = 0;
+
+        if (!user_mode(regs)) {
+                /* kprobe_running() needs smp_processor_id() */
+                preempt_disable();
+                if (kprobe_running() && kprobes_fault_handler(regs, trap))
+                        ret = 1;
+                preempt_enable();
+        }
 
-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);
+        return ret;
 }
 #else
-static inline int notify_page_fault(enum die_val val, const char *str,
-                        struct pt_regs *regs, long err, int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
 {
-        return NOTIFY_DONE;
+        return 0;
 }
 #endif
 
@@ -117,8 +105,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
         /*
          * This is to handle the kprobes on user space access instructions
          */
-        if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
-                                        SIGSEGV) == NOTIFY_STOP)
+        if (notify_page_fault(regs, TRAP_BRKPT))
                 return;
 
         down_read(&mm->mmap_sem);