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authorAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>2006-06-26 09:25:25 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 18:58:22 +0200
commitb71b5b652852db1b499d22aaabed8f5043acafad (patch)
tree82f5e0c8090515fc8886f26540a3b00ae603ae77
parent[PATCH] Notify page fault call chain for x86_64 (diff)
downloadlinux-b71b5b652852db1b499d22aaabed8f5043acafad.tar.xz
linux-b71b5b652852db1b499d22aaabed8f5043acafad.zip
[PATCH] Notify page fault call chain for i386
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/i386/mm/fault.c38
-rw-r--r--include/asm-i386/kdebug.h2
2 files changed, 38 insertions, 2 deletions
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index bd6fe96cc16d..6ee7faaf2c1b 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -30,6 +30,40 @@
extern void die(const char *,struct pt_regs *,long);
+#ifdef CONFIG_KPROBES
+ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
+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
+
+
/*
* Unlock any spinlocks which will prevent us from getting the
* message out
@@ -324,7 +358,7 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs,
if (unlikely(address >= TASK_SIZE)) {
if (!(error_code & 0x0000000d) && 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;
/*
@@ -334,7 +368,7 @@ fastcall 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-i386/kdebug.h b/include/asm-i386/kdebug.h
index 96d0828ce096..d18cdb9fc9a6 100644
--- a/include/asm-i386/kdebug.h
+++ b/include/asm-i386/kdebug.h
@@ -19,6 +19,8 @@ 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 i386die_chain;