From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Wed, 16 May 2007 12:52:19 +0000 Subject: Re: [PATCH] ia64: optimize pagefaults a little Message-Id: <20070516125219.GA581@lst.de> List-Id: References: <20070512155724.GB8412@lst.de> In-Reply-To: <20070512155724.GB8412@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Sorry for the brokenness - I set up a ia64 cross-compile enviroment to make sure it really compiles fine but forgot to turn CONFIG_KPROBES on. Here's the corrected patch: Signed-off-by: Christoph Hellwig Index: linux-2.6/arch/ia64/kernel/kprobes.c =================================--- linux-2.6.orig/arch/ia64/kernel/kprobes.c 2007-05-16 11:45:10.000000000 +0200 +++ linux-2.6/arch/ia64/kernel/kprobes.c 2007-05-16 12:36:31.000000000 +0200 @@ -820,7 +820,7 @@ out: return 1; } -static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr) +int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); @@ -904,13 +904,6 @@ int __kprobes kprobe_exceptions_notify(s if (post_kprobes_handler(args->regs)) ret = NOTIFY_STOP; break; - case DIE_PAGE_FAULT: - /* kprobe_running() needs smp_processor_id() */ - preempt_disable(); - if (kprobe_running() && - kprobes_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - preempt_enable(); default: break; } Index: linux-2.6/arch/ia64/mm/fault.c =================================--- linux-2.6.orig/arch/ia64/mm/fault.c 2007-05-16 11:45:10.000000000 +0200 +++ linux-2.6/arch/ia64/mm/fault.c 2007-05-16 11:51:23.000000000 +0200 @@ -19,36 +19,24 @@ 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) +static inline int notify_page_fault(struct pt_regs *regs, int trap) { - return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); -} + int ret = 0; -int unregister_page_fault_notifier(struct notifier_block *nb) -{ - return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); -} + if (!user_mode(regs)) { + /* kprobe_running() needs smp_processor_id() */ + preempt_disable(); + if (kprobe_running() && kprobes_fault_handler(regs, trap)) + ret = 1; + preempt_enable(); + } -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); + return ret; } #else -static inline int notify_page_fault(enum die_val val, const char *str, - struct pt_regs *regs, long err, int trap, int sig) +static inline int notify_page_fault(struct pt_regs *regs, int trap) { - return NOTIFY_DONE; + return 0; } #endif @@ -117,8 +105,7 @@ ia64_do_page_fault (unsigned long addres /* * This is to handle the kprobes on user space access instructions */ - if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT, - SIGSEGV) = NOTIFY_STOP) + if (notify_page_fault(regs, TRAP_BRKPT)) return; down_read(&mm->mmap_sem); Index: linux-2.6/include/asm-ia64/kprobes.h =================================--- linux-2.6.orig/include/asm-ia64/kprobes.h 2007-05-16 11:45:10.000000000 +0200 +++ linux-2.6/include/asm-ia64/kprobes.h 2007-05-16 11:45:12.000000000 +0200 @@ -120,6 +120,7 @@ struct arch_specific_insn { unsigned short slot; }; +extern int kprobes_fault_handler(struct pt_regs *regs, int trapnr); extern int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); Index: linux-2.6/include/asm-ia64/kdebug.h =================================--- linux-2.6.orig/include/asm-ia64/kdebug.h 2007-05-16 11:45:10.000000000 +0200 +++ linux-2.6/include/asm-ia64/kdebug.h 2007-05-16 11:45:12.000000000 +0200 @@ -28,14 +28,24 @@ */ #include -extern int register_page_fault_notifier(struct notifier_block *); -extern int unregister_page_fault_notifier(struct notifier_block *); +/* + * These are only here because kprobes.c wants them to implement a + * blatant layering violation. Will hopefully go away soon once all + * architectures are updated. + */ +static inline int register_page_fault_notifier(struct notifier_block *nb) +{ + return 0; +} +static inline int unregister_page_fault_notifier(struct notifier_block *nb) +{ + return 0; +} enum die_val { DIE_BREAK = 1, DIE_FAULT, DIE_OOPS, - DIE_PAGE_FAULT, DIE_MACHINE_HALT, DIE_MACHINE_RESTART, DIE_MCA_MONARCH_ENTER,