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Violators will be prosecuted for from ; Fri, 18 Nov 2016 21:39:52 +1000 Received: from d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id EC6C73578052 for ; Fri, 18 Nov 2016 22:39:48 +1100 (EST) Received: from d23av06.au.ibm.com (d23av06.au.ibm.com [9.190.235.151]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uAIBdmPk33292482 for ; Fri, 18 Nov 2016 22:39:48 +1100 Received: from d23av06.au.ibm.com (localhost [127.0.0.1]) by d23av06.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uAIBdmPE011393 for ; Fri, 18 Nov 2016 22:39:48 +1100 From: "Naveen N. Rao" To: Michael Ellerman , Masami Hiramatsu Cc: Anton Blanchard , linuxppc-dev@lists.ozlabs.org, Ananth N Mavinakayanahalli Subject: [PATCH] powerpc: kprobes: invoke handlers directly Date: Fri, 18 Nov 2016 17:09:26 +0530 Message-Id: <20161118113926.31350-1-naveen.n.rao@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , ... rather than through notify_die(), to reduce path taken for handling kprobes. Similar to commit 6f6343f53d13 ("kprobes/x86: Call exception handlers directly from do_int3/do_debug"). While at it, rename post_kprobe_handler() to kprobe_post_handler() for more uniform naming. Reported-by: Masami Hiramatsu Signed-off-by: Naveen N. Rao --- arch/powerpc/include/asm/kprobes.h | 2 ++ arch/powerpc/kernel/kprobes.c | 29 +++++++---------------------- arch/powerpc/kernel/traps.c | 20 ++++++++++++++++++++ 3 files changed, 29 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h index 2c9759bd..47c60d0 100644 --- a/arch/powerpc/include/asm/kprobes.h +++ b/arch/powerpc/include/asm/kprobes.h @@ -126,6 +126,8 @@ struct kprobe_ctlblk { extern int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); +extern int kprobe_handler(struct pt_regs *regs); +extern int kprobe_post_handler(struct pt_regs *regs); extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr); #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_KPROBES_H */ diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 9479d8e..ad108b8 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -140,13 +140,16 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, regs->link = (unsigned long)kretprobe_trampoline; } -static int __kprobes kprobe_handler(struct pt_regs *regs) +int __kprobes kprobe_handler(struct pt_regs *regs) { struct kprobe *p; int ret = 0; unsigned int *addr = (unsigned int *)regs->nip; struct kprobe_ctlblk *kcb; + if (user_mode(regs)) + return 0; + /* * We don't want to be preempted for the entire * duration of kprobe processing @@ -359,12 +362,12 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, * single-stepped a copy of the instruction. The address of this * copy is p->ainsn.insn. */ -static int __kprobes post_kprobe_handler(struct pt_regs *regs) +int __kprobes kprobe_post_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - if (!cur) + if (!cur || user_mode(regs)) return 0; /* make sure we got here for instruction we have a kprobe on */ @@ -470,25 +473,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) int __kprobes kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data) { - struct die_args *args = (struct die_args *)data; - int ret = NOTIFY_DONE; - - if (args->regs && user_mode(args->regs)) - return ret; - - switch (val) { - case DIE_BPT: - if (kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - case DIE_SSTEP: - if (post_kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - default: - break; - } - return ret; + return NOTIFY_DONE; } unsigned long arch_deref_entry_point(void *entry) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 91d278c..dbcdf48 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -824,6 +824,11 @@ void single_step_exception(struct pt_regs *regs) clear_single_step(regs); +#ifdef CONFIG_KPROBES + if (kprobe_post_handler(regs)) + return; +#endif + if (notify_die(DIE_SSTEP, "single_step", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) goto bail; @@ -1177,6 +1182,11 @@ void program_check_exception(struct pt_regs *regs) if (debugger_bpt(regs)) goto bail; +#ifdef CONFIG_KPROBES + if (kprobe_handler(regs)) + goto bail; +#endif + /* trap exception */ if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) @@ -1745,6 +1755,11 @@ void DebugException(struct pt_regs *regs, unsigned long debug_status) return; } +#ifdef CONFIG_KPROBES + if (kprobe_post_handler(regs)) + return; +#endif + if (notify_die(DIE_SSTEP, "block_step", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) { return; @@ -1759,6 +1774,11 @@ void DebugException(struct pt_regs *regs, unsigned long debug_status) /* Clear the instruction completion event */ mtspr(SPRN_DBSR, DBSR_IC); +#ifdef CONFIG_KPROBES + if (kprobe_post_handler(regs)) + return; +#endif + if (notify_die(DIE_SSTEP, "single_step", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) { return; -- 2.10.2