From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3tNDTD3SFgzDvw8 for ; Tue, 22 Nov 2016 16:25:51 +1100 (AEDT) Date: Tue, 22 Nov 2016 14:25:37 +0900 From: Masami Hiramatsu To: "Naveen N. Rao" Cc: Michael Ellerman , Anton Blanchard , linuxppc-dev@lists.ozlabs.org, Ananth N Mavinakayanahalli Subject: Re: [PATCH v2 2/2] powerpc: kprobes: invoke handlers directly Message-Id: <20161122142537.42e365a22d866026aa726bfe@kernel.org> In-Reply-To: <1bde4adb6da9695007f409af9ea4db6be400ca54.1479745635.git.naveen.n.rao@linux.vnet.ibm.com> References: <9dd0626d840e60b15603d767ce1576630fe1376d.1479745635.git.naveen.n.rao@linux.vnet.ibm.com> <1bde4adb6da9695007f409af9ea4db6be400ca54.1479745635.git.naveen.n.rao@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello Naveen, On Mon, 21 Nov 2016 22:36:41 +0530 "Naveen N. Rao" wrote: > ... 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 > --- > Changes since v1: > - Removed CONFIG_KPROBES guard in traps.c > - Introduce CONFIG_KPROBES guard in asm/kprobes.h to prevent conflicts when > including both linux/kprobes.h as well as asm/kprobes.h > > arch/powerpc/include/asm/kprobes.h | 7 +++++++ > arch/powerpc/kernel/kprobes.c | 29 +++++++---------------------- > arch/powerpc/kernel/traps.c | 13 +++++++++++++ > 3 files changed, 27 insertions(+), 22 deletions(-) > > diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h > index 2c9759bd..da30dc3 100644 > --- a/arch/powerpc/include/asm/kprobes.h > +++ b/arch/powerpc/include/asm/kprobes.h > @@ -32,6 +32,7 @@ > #include > #include > > +#ifdef CONFIG_KPROBES > #define __ARCH_WANT_KPROBES_INSN_SLOT > > struct pt_regs; > @@ -127,5 +128,11 @@ struct kprobe_ctlblk { > extern int kprobe_exceptions_notify(struct notifier_block *self, > unsigned long val, void *data); > extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr); > +extern int kprobe_handler(struct pt_regs *regs); > +extern int kprobe_post_handler(struct pt_regs *regs); > +#else > +static int kprobe_handler(struct pt_regs *regs) { return 0; } > +static int kprobe_post_handler(struct pt_regs *regs) { return 0; } These should be "static inline int kprobe_...", you lost 'inline' here. Others are OK for me. Thanks, > +#endif /* CONFIG_KPROBES */ > #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..38d5fbf 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -64,6 +64,7 @@ > #include > #include > #include > +#include > > #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC) > int (*__debugger)(struct pt_regs *regs) __read_mostly; > @@ -824,6 +825,9 @@ void single_step_exception(struct pt_regs *regs) > > clear_single_step(regs); > > + if (kprobe_post_handler(regs)) > + return; > + > if (notify_die(DIE_SSTEP, "single_step", regs, 5, > 5, SIGTRAP) == NOTIFY_STOP) > goto bail; > @@ -1177,6 +1181,9 @@ void program_check_exception(struct pt_regs *regs) > if (debugger_bpt(regs)) > goto bail; > > + if (kprobe_handler(regs)) > + goto bail; > + > /* trap exception */ > if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP) > == NOTIFY_STOP) > @@ -1745,6 +1752,9 @@ void DebugException(struct pt_regs *regs, unsigned long debug_status) > return; > } > > + if (kprobe_post_handler(regs)) > + return; > + > if (notify_die(DIE_SSTEP, "block_step", regs, 5, > 5, SIGTRAP) == NOTIFY_STOP) { > return; > @@ -1759,6 +1769,9 @@ void DebugException(struct pt_regs *regs, unsigned long debug_status) > /* Clear the instruction completion event */ > mtspr(SPRN_DBSR, DBSR_IC); > > + if (kprobe_post_handler(regs)) > + return; > + > if (notify_die(DIE_SSTEP, "single_step", regs, 5, > 5, SIGTRAP) == NOTIFY_STOP) { > return; > -- > 2.10.2 > -- Masami Hiramatsu