From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1545AC433F5 for ; Sat, 8 Oct 2022 03:10:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229624AbiJHDKs (ORCPT ); Fri, 7 Oct 2022 23:10:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229452AbiJHDKm (ORCPT ); Fri, 7 Oct 2022 23:10:42 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16160A2222; Fri, 7 Oct 2022 20:10:38 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MkqnW5LF8zlXhx; Sat, 8 Oct 2022 11:06:07 +0800 (CST) Received: from dggpemm500013.china.huawei.com (7.185.36.172) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 8 Oct 2022 11:10:36 +0800 Received: from [10.67.108.67] (10.67.108.67) by dggpemm500013.china.huawei.com (7.185.36.172) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 8 Oct 2022 11:10:36 +0800 Message-ID: <6b4ccb6b-c6c2-e0cc-1670-1776877ecf46@huawei.com> Date: Sat, 8 Oct 2022 11:10:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.0 Subject: Re: [PATCH v3] ARM: kprobes: move __kretprobe_trampoline to out of line assembler Content-Language: en-US To: Nick Desaulniers CC: "Naveen N . Rao" , Anil S Keshavamurthy , "David S . Miller" , Arnd Bergmann , Nathan Chancellor , Tom Rix , sparkhuang , Ard Biesheuvel , Steven Rostedt , Linus Walleij , , , , , Naresh Kamboju , , , "Linux Kernel Functional Testing" , Logan Chien , Masami Hiramatsu , Russell King References: <202209291607.0MlscIht-lkp@intel.com> <20220930211505.209939-1-ndesaulniers@google.com> From: Chen Zhongjin In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.108.67] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500013.china.huawei.com (7.185.36.172) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Sorry for late reply because I just found this thread before the long vacation so I didn't have much time to deal with it. On 2022/10/7 4:35, Nick Desaulniers wrote: > On Fri, Sep 30, 2022 at 2:15 PM Nick Desaulniers > wrote: >> commit 1069c1dd20a3 ("ARM: 9231/1: Recover kretprobes return address for >> EABI stack unwinder") >> tickled a bug in clang's integrated assembler where the .save and .pad >> directives must have corresponding .fnstart directives. The integrated >> assembler is unaware that the compiler will be generating the .fnstart >> directive. >> >> arch/arm/probes/kprobes/core.c:409:30: error: .fnstart must precede >> .save or .vsave directives >> :3:2: note: instantiated into assembly here >> .save {sp, lr, pc} >> ^ >> arch/arm/probes/kprobes/core.c:412:29: error: .fnstart must precede >> .pad directive >> :6:2: note: instantiated into assembly here >> .pad #52 >> ^ >> > Chen, I noticed that your patch was discarded; it's not in linux-next today. > https://lore.kernel.org/linux-arm-kernel/YzHPGvhLkdQcDYzx@shell.armlinux.org.uk/ > https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=9231/1 > How would you like to proceed here? Since 6.1 is closing now. Let's reorganize everything and queue it up for -next for 6.2 > I think moving this out of line, incorporating Ard's feedback, then > putting the UNWIND directives on top might be the way to go. What do > you think? This way looks good to me. How about making a set for this,  to make everything more clear: 1. Move this out of line 2. Apply the feature, test with gcc & clang 3. Other cleaning, or merge with 2 if the cleaning is tiny. I'll send another version for this, rebased to 6.1-rc1 Thanks for your time! Best, Chen