From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755681Ab3AHLj3 (ORCPT ); Tue, 8 Jan 2013 06:39:29 -0500 Received: from e39.co.us.ibm.com ([32.97.110.160]:32826 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754171Ab3AHLj2 (ORCPT ); Tue, 8 Jan 2013 06:39:28 -0500 Date: Tue, 8 Jan 2013 17:09:01 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ingo Molnar , Peter Zijlstra , Ananth N Mavinakayanahalli , Anton Arapov , Frank Eigler , Josh Stone , "Suzuki K. Poulose" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] uprobes: Change handle_swbp() to expose bp_vaddr to handler_chain() Message-ID: <20130108113901.GC1325@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20121230154657.GA28488@redhat.com> <20121230154722.GA28513@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20121230154722.GA28513@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13010811-3620-0000-0000-000000D6B059 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [2012-12-30 16:47:22]: > Change handle_swbp() to set regs->ip = bp_vaddr in advance, this is > what consumer->handler() needs but uprobe_get_swbp_addr() is not > exported. > > This also simplifies the code and makes it more consistent across > the supported architectures. handle_swbp() becomes the only caller > of uprobe_get_swbp_addr(). > > Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju > --- > arch/x86/kernel/uprobes.c | 1 - > kernel/events/uprobes.c | 15 +++++++-------- > kernel/trace/trace_uprobe.c | 4 ++-- > 3 files changed, 9 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c > index 4e33a35..0ba4cfb 100644 > --- a/arch/x86/kernel/uprobes.c > +++ b/arch/x86/kernel/uprobes.c > @@ -681,7 +681,6 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) > continue; > > if (auprobe->insn[i] == 0x90) { > - regs->ip = uprobe_get_swbp_addr(regs); > regs->ip += i + 1; > return true; > } > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index 59b6e97..f883813 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1504,6 +1504,10 @@ static void handle_swbp(struct pt_regs *regs) > } > return; > } > + > + /* change it in advance for ->handler() and restart */ > + instruction_pointer_set(regs, bp_vaddr); > + > /* > * TODO: move copy_insn/etc into _register and remove this hack. > * After we hit the bp, _unregister + _register can install the > @@ -1511,14 +1515,14 @@ static void handle_swbp(struct pt_regs *regs) > */ > smp_rmb(); /* pairs with wmb() in install_breakpoint() */ > if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) > - goto restart; > + goto out; > > utask = current->utask; > if (!utask) { > utask = add_utask(); > /* Cannot allocate; re-execute the instruction. */ > if (!utask) > - goto restart; > + goto out; > } > > handler_chain(uprobe, regs); > @@ -1531,12 +1535,7 @@ static void handle_swbp(struct pt_regs *regs) > return; > } > > -restart: > - /* > - * cannot singlestep; cannot skip instruction; > - * re-execute the instruction. > - */ > - instruction_pointer_set(regs, bp_vaddr); > + /* can_skip_sstep() succeeded, or restart if can't singlestep */ > out: > put_uprobe(uprobe); > } > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index 38eee92..52caead 100644 > --- a/kernel/trace/trace_uprobe.c > +++ b/kernel/trace/trace_uprobe.c > @@ -488,7 +488,7 @@ static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) > return; > > entry = ring_buffer_event_data(event); > - entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); > + entry->ip = instruction_pointer(task_pt_regs(current)); > data = (u8 *)&entry[1]; > for (i = 0; i < tu->nr_args; i++) > call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); > @@ -663,7 +663,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) > if (!entry) > goto out; > > - entry->ip = uprobe_get_swbp_addr(task_pt_regs(current)); > + entry->ip = instruction_pointer(task_pt_regs(current)); > data = (u8 *)&entry[1]; > for (i = 0; i < tu->nr_args; i++) > call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); > -- > 1.5.5.1 >