From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933271AbcHJUtS (ORCPT ); Wed, 10 Aug 2016 16:49:18 -0400 Received: from mail-qk0-f177.google.com ([209.85.220.177]:33067 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932235AbcHJUtO (ORCPT ); Wed, 10 Aug 2016 16:49:14 -0400 Subject: Re: [PATCH v15 04/10] arm64: Kprobes with single stepping support To: Catalin Marinas References: <57924104.1080202@linaro.org> <20160725171350.GE2423@e104818-lin.cambridge.arm.com> <57969234.1070201@linaro.org> <22b277ba-6812-a0dd-9e8e-c29bdb3aa672@linaro.org> <57993211.1040600@linaro.org> <20160728144053.GA26510@e104818-lin.cambridge.arm.com> <360d582b-5401-7126-ef40-bd78369c0a34@linaro.org> <57A2C8DF.7050401@linaro.org> <74b8c503-b6df-dcb1-c278-d49850fe3715@linaro.org> <57A89731.20709@linaro.org> <20160809172308.GD15447@e104818-lin.cambridge.arm.com> Cc: Daniel Thompson , Mark Rutland , Petr Mladek , Zi Shen Lim , Will Deacon , sparclinux , Andrey Ryabinin , yalin wang , Li Bin , Jisheng Zhang , John Blackwood , Pratyush Anand , Huang Shijie , Dave P Martin , Yang Shi , Vladimir Murzin , Steve Capper , Suzuki K Poulose , Marc Zyngier , Mark Brown , Sandeepa Prabhu , William Cohen , =?UTF-8?Q?Alex_Benn=c3=a9e?= , Adam Buchbinder , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , linux-kernel@vger.kernel.org, James Morse , Masami Hiramatsu , Andrew Morton , Robin Murphy , Jens Wiklander , Christoffer Dall From: David Long Message-ID: <57AB9196.1080005@linaro.org> Date: Wed, 10 Aug 2016 16:41:58 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20160809172308.GD15447@e104818-lin.cambridge.arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/09/2016 01:23 PM, Catalin Marinas wrote: > On Mon, Aug 08, 2016 at 10:29:05AM -0400, David Long wrote: >> On 08/08/2016 07:13 AM, Daniel Thompson wrote: >>> On 04/08/16 05:47, David Long wrote: >>> >From b451caa1adaf1d03e08a44b5dad3fca31cebd97a Mon Sep 17 00:00:00 2001 >>>> From: "David A. Long" >>>> Date: Thu, 4 Aug 2016 00:35:33 -0400 >>>> Subject: [PATCH] arm64: Remove stack duplicating code from jprobes >>>> >>>> Because the arm64 calling standard allows stacked function arguments >>>> to be >>>> anywhere in the stack frame, do not attempt to duplicate the stack >>>> frame for >>>> jprobes handler functions. >>>> >>>> Signed-off-by: David A. Long >>>> --- >>>> Documentation/kprobes.txt | 7 +++++++ >>>> arch/arm64/include/asm/kprobes.h | 2 -- >>>> arch/arm64/kernel/probes/kprobes.c | 31 +++++-------------------------- >>>> 3 files changed, 12 insertions(+), 28 deletions(-) >>>> >>>> diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt >>>> index 1f9b3e2..bd01839 100644 >>>> --- a/Documentation/kprobes.txt >>>> +++ b/Documentation/kprobes.txt >>>> @@ -103,6 +103,13 @@ Note that the probed function's args may be >>>> passed on the stack >>>> or in registers. The jprobe will work in either case, so long as the >>>> handler's prototype matches that of the probed function. >>>> >>>> +Note that in some architectures (e.g.: arm64) the stack copy is not >>> >>> Could sparc64 be added to this list? >>> >>> For the sparc folks who are new to the thread, we've previously >>> established that the sparc64 ABI passes large structures by >>> allocating them from the caller's stack frame and passing a pointer >>> to the stack frame (i.e. arguments may not be at top of the stack). >>> We also noticed that sparc code does not save/restore anything from >>> the stack. >> >> I was reluctant to do that in the context of late changes to v4.8 for arm64 >> but now that any changes for this are going in as a new patch it would >> indeed be useful to get involvement from sparc maintainers. > > I'm happy to take the arm64 patch for 4.8 as it's mainly a clean-up. > Whether you can mention sparc64 as well, it depends on the sparc > maintainers. You can either cc them or send the series as two patches, > one for documentation and the other for arm64. > I didn't think that was going to be possible after v4.8-rc1. I have separated the documentation and code changes. I will send out the new code-only patch (otherwise unchanged in content) momentarily. Thanks, -dl