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 C4D4EC433EF for ; Wed, 2 Feb 2022 09:25:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231933AbiBBJZn (ORCPT ); Wed, 2 Feb 2022 04:25:43 -0500 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:58694 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245500AbiBBJZl (ORCPT ); Wed, 2 Feb 2022 04:25:41 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=ashimida@linux.alibaba.com;NM=1;PH=DS;RN=15;SR=0;TI=SMTPD_---0V3RLRGY_1643793937; Received: from 192.168.193.142(mailfrom:ashimida@linux.alibaba.com fp:SMTPD_---0V3RLRGY_1643793937) by smtp.aliyun-inc.com(127.0.0.1); Wed, 02 Feb 2022 17:25:39 +0800 Message-ID: <7adf6644-55ce-d90e-2f62-66792364d337@linux.alibaba.com> Date: Wed, 2 Feb 2022 01:25:33 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PING^3][PATCH,v2,1/1,AARCH64][PR102768] aarch64: Add compiler support for Shadow Call Stack Content-Language: en-US To: Ard Biesheuvel , gcc-patches@gcc.gnu.org, Richard Earnshaw , marcus.shawcroft@arm.com, Kyrylo Tkachov , hp@gcc.gnu.org, Nick Desaulniers , nsz@gcc.gnu.org, pageexec@gmail.com, qinzhao@gcc.gnu.org, linux-hardening@vger.kernel.org, Peter Collingbourne , Sami Tolvanen , Kees Cook , richard.sandiford@arm.com References: <20211102070616.119780-1-ashimida@linux.alibaba.com> <81d54b71-7c9c-47ef-ac8d-72aae46cd4ee@linux.alibaba.com> <3ae4a533-352b-f3e3-27b3-9386df5f56c3@linux.alibaba.com> <61acb6f4-9a86-ddad-e48c-c68e4bcb08f1@linux.alibaba.com> <3f2027af-bbe0-f46f-2ceb-bffc4bbbf70e@linux.alibaba.com> From: Dan Li In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On 1/31/22 08:26, Richard Sandiford wrote: > Thanks for the discussion and sorry for the slow reply, was out most of > last week. > > Dan Li writes: >> Thanks, Ard, >> >> On 1/26/22 00:10, Ard Biesheuvel wrote: >>> On Wed, 26 Jan 2022 at 08:53, Dan Li wrote: >>>> >>>> Hi, all, >>>> >>>> Sorry for bothering. >>>> >>>> I'm trying to commit aarch64 scs code to the gcc and there is an issue >>>> that I'm not sure about, could someone give me some suggestions? >>>> (To avoid noise, I did't cc PING^3 [1] to the kernel mail list :) ) >>>> >>> So omitting the load of X30 from the ordinary stack seems fine to me. > > OK, thanks. Let's go with that for now then. There would still be > time to change our minds before GCC 12 is released, if anyone feels > that patching SCS code would be useful. >> Reading it back, I think my previous message came across as sounding > like a complaint against binary patching, which wasn't the case at all. > I think it would be fine to support patching, even if it was just for a > single vendor rather than expected to be a common case. It's just that, > if we did want to support it, we'd need to document it as a requirement > (at least within GCC) and change the implementation accordingly. > Got it, then I'll implement this feature as discussed above and see if we could add additional options for SCS later. Thanks, Dan