From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932150AbWDTXwr (ORCPT ); Thu, 20 Apr 2006 19:52:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932143AbWDTXvK (ORCPT ); Thu, 20 Apr 2006 19:51:10 -0400 Received: from mga05.intel.com ([192.55.52.89]:445 "EHLO fmsmga101.fm.intel.com") by vger.kernel.org with ESMTP id S932146AbWDTXvD (ORCPT ); Thu, 20 Apr 2006 19:51:03 -0400 X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="26631676:sNHT19042499" X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="25831819:sNHT25667348" TrustExchangeSourcedMail: True X-IronPort-AV: i="4.04,142,1144047600"; d="scan'208"; a="26631645:sNHT33399835" Message-Id: <20060420233912.223913083@csdlinux-2.jf.intel.com> References: <20060420232456.712271992@csdlinux-2.jf.intel.com> Date: Thu, 20 Apr 2006 16:25:01 -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 5/7] Notify page fault call chain for sparc64 Content-Disposition: inline; filename=notify_page_fault_sparc64.patch X-OriginalArrivalTime: 20 Apr 2006 23:51:00.0114 (UTC) FILETIME=[468DAF20:01C664D5] 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/sparc64/mm/fault.c | 36 +++++++++++++++++++++++++++++++++++- include/asm-sparc64/kdebug.h | 2 ++ 2 files changed, 37 insertions(+), 1 deletion(-) Index: linux-2.6.17-rc1-mm3/arch/sparc64/mm/fault.c =================================================================== --- linux-2.6.17-rc1-mm3.orig/arch/sparc64/mm/fault.c +++ linux-2.6.17-rc1-mm3/arch/sparc64/mm/fault.c @@ -31,6 +31,40 @@ #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 + /* * To debug kernel to catch accesses to certain virtual/physical addresses. * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints. @@ -263,7 +297,7 @@ asmlinkage void __kprobes do_sparc64_fau fault_code = get_thread_fault_code(); - if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, + if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, fault_code, 0, SIGSEGV) == NOTIFY_STOP) return; Index: linux-2.6.17-rc1-mm3/include/asm-sparc64/kdebug.h =================================================================== --- linux-2.6.17-rc1-mm3.orig/include/asm-sparc64/kdebug.h +++ linux-2.6.17-rc1-mm3/include/asm-sparc64/kdebug.h @@ -17,6 +17,8 @@ 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 sparc64die_chain; extern void bad_trap(struct pt_regs *, long); --