From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932141AbWDTXvG (ORCPT ); Thu, 20 Apr 2006 19:51:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932148AbWDTXvG (ORCPT ); Thu, 20 Apr 2006 19:51:06 -0400 Received: from mga06.intel.com ([134.134.136.21]:48206 "EHLO orsmga101.jf.intel.com") by vger.kernel.org with ESMTP id S932141AbWDTXvC (ORCPT ); Thu, 20 Apr 2006 19:51:02 -0400 X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="25813696:sNHT16687874" X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="25831799:sNHT18140101" TrustExchangeSourcedMail: True X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="25813664:sNHT20889064" Message-Id: <20060420233912.045800746@csdlinux-2.jf.intel.com> References: <20060420232456.712271992@csdlinux-2.jf.intel.com> Date: Thu, 20 Apr 2006 16:25:00 -0700 From: Anil S Keshavamurthy To: Anderw Morton Cc: LKML , Keith Owens , Dean Nelson , Tony Luck , Anath Mavinakayanahalli , Prasanna Panchamukhi , Dave M , Andi Kleen , Anil S Keshavamurthy Subject: [(take 2)patch 4/7] Notify page fault call chain for powerpc Content-Disposition: inline; filename=notify_page_fault_powerpc.patch X-OriginalArrivalTime: 20 Apr 2006 23:51:00.0036 (UTC) FILETIME=[4681C840:01C664D5] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. Changes since previous version: 1) Moved the implementaion of register/unregister_page_fault_notifier() call to arch/xxx/mm/fault.c 2) Added #ifdef CONFIG_KPROBES around this register/unregister calls as currently kprobes is the only potential user. Signed-off-by: Anil S Keshavamurthy --- arch/powerpc/mm/fault.c | 36 +++++++++++++++++++++++++++++++++++- include/asm-powerpc/kdebug.h | 2 ++ 2 files changed, 37 insertions(+), 1 deletion(-) Index: linux-2.6.17-rc1-mm3/arch/powerpc/mm/fault.c =================================================================== --- linux-2.6.17-rc1-mm3.orig/arch/powerpc/mm/fault.c +++ linux-2.6.17-rc1-mm3/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_re 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; Index: linux-2.6.17-rc1-mm3/include/asm-powerpc/kdebug.h =================================================================== --- linux-2.6.17-rc1-mm3.orig/include/asm-powerpc/kdebug.h +++ linux-2.6.17-rc1-mm3/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. */ --