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authorAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>2006-06-26 00:25:26 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 09:58:22 -0700
commitae9a5b85655d7133ab8e7c99b742ef20c8dbb7d2 (patch)
tree011bf055ef888a4cfb949fec467bd6385a090d12
parentb71b5b652852db1b499d22aaabed8f5043acafad (diff)
[PATCH] Notify page fault call chain for ia64
Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/ia64/mm/fault.c36
-rw-r--r--include/asm-ia64/kdebug.h2
2 files changed, 37 insertions, 1 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index d98ec49570b..14ef7cceb20 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -19,6 +19,40 @@
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)
+{
+ 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
+
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
@@ -84,7 +118,7 @@ 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_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
+ if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
SIGSEGV) == NOTIFY_STOP)
return;
diff --git a/include/asm-ia64/kdebug.h b/include/asm-ia64/kdebug.h
index c195a9ad125..aed7142f9e4 100644
--- a/include/asm-ia64/kdebug.h
+++ b/include/asm-ia64/kdebug.h
@@ -40,6 +40,8 @@ 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 ia64die_chain;
enum die_val {