From 4f9e87c0454059e80f3811f95ad9f40ed28c69a2 Mon Sep 17 00:00:00 2001 From: Anil S Keshavamurthy Date: Mon, 26 Jun 2006 00:25:27 -0700 Subject: [PATCH] [PATCH] Notify page fault call chain for powerpc 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/mm/fault.c | 36 +++++++++++++++++++++++++++++++++++- include/asm-powerpc/kdebug.h | 2 ++ 2 files changed, 37 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index fdbba4206d..a0a9e1e006 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -40,6 +40,40 @@ #include #include +#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(¬ify_page_fault_chain, nb); +} + +int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(¬ify_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(¬ify_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 + /* * Check whether the instruction at regs->nip is a store using * an update addressing form which will update r1. @@ -142,7 +176,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, is_write = error_code & ESR_DST; #endif /* CONFIG_4xx || CONFIG_BOOKE */ - if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, error_code, + if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, error_code, 11, SIGSEGV) == NOTIFY_STOP) return 0; diff --git a/include/asm-powerpc/kdebug.h b/include/asm-powerpc/kdebug.h index c01786ab5f..532bfee934 100644 --- a/include/asm-powerpc/kdebug.h +++ b/include/asm-powerpc/kdebug.h @@ -18,6 +18,8 @@ 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 powerpc_die_chain; /* Grossly misnamed. */ -- 2.39.5