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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1A29C433E2 for ; Tue, 15 Sep 2020 20:16:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6D02020731 for ; Tue, 15 Sep 2020 20:16:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D02020731 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B8598900061; Tue, 15 Sep 2020 16:16:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B0EC0900028; Tue, 15 Sep 2020 16:16:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9D850900061; Tue, 15 Sep 2020 16:16:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0028.hostedemail.com [216.40.44.28]) by kanga.kvack.org (Postfix) with ESMTP id 819E4900028 for ; Tue, 15 Sep 2020 16:16:51 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 41D68362A for ; Tue, 15 Sep 2020 20:16:51 +0000 (UTC) X-FDA: 77266404222.24.nerve35_500c7ed27114 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 2AB7A1A4A7 for ; Tue, 15 Sep 2020 20:16:51 +0000 (UTC) X-HE-Tag: nerve35_500c7ed27114 X-Filterd-Recvd-Size: 4860 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Tue, 15 Sep 2020 20:16:49 +0000 (UTC) IronPort-SDR: Zq7GPQKWwK4yZRaVCziOlEhySoNuIMI9bBQN8a1iDApVPoJ6TDlNyLx6NQrr7rb3dBO1dx6sFn yDt2mW9L639g== X-IronPort-AV: E=McAfee;i="6000,8403,9745"; a="244177484" X-IronPort-AV: E=Sophos;i="5.76,430,1592895600"; d="scan'208";a="244177484" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2020 13:16:44 -0700 IronPort-SDR: C21JFcp5L3IyVaR6VNoNRpn9g5UUxFHa0FtfPv5gaDUxRuFfz+O+12WK+kTXZovTK9h1xkn+TF gyWGw97/7pKA== X-IronPort-AV: E=Sophos;i="5.76,430,1592895600"; d="scan'208";a="302292684" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.209.27.25]) ([10.209.27.25]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2020 13:16:42 -0700 Subject: Re: [NEEDS-REVIEW] Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack To: Dave Hansen , Andy Lutomirski Cc: Dave Martin , "H.J. Lu" , Florian Weimer , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , "open list:DOCUMENTATION" , Linux-MM , linux-arch , Linux API , Arnd Bergmann , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Weijiang Yang References: <086c73d8-9b06-f074-e315-9964eb666db9@intel.com> <20200901102758.GY6642@arm.com> <32005d57-e51a-7c7f-4e86-612c2ff067f3@intel.com> <46dffdfd-92f8-0f05-6164-945f217b0958@intel.com> <6e1e22a5-1b7f-2783-351e-c8ed2d4893b8@intel.com> <5979c58d-a6e3-d14d-df92-72cdeb97298d@intel.com> <08c91835-8486-9da5-a7d1-75e716fc5d36@intel.com> <41aa5e8f-ad88-2934-6d10-6a78fcbe019b@intel.com> <2f137667122486a0cea3b0dbfa99d02f74870673.camel@intel.com> <6a04252c-da02-0217-270b-650bd3d852c7@intel.com> From: "Yu, Yu-cheng" Message-ID: <439e1e08-58c0-ac91-b073-a471111ad8e2@intel.com> Date: Tue, 15 Sep 2020 13:16:41 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <6a04252c-da02-0217-270b-650bd3d852c7@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 2AB7A1A4A7 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 9/15/2020 12:24 PM, Dave Hansen wrote: > On 9/15/20 12:08 PM, Yu-cheng Yu wrote: >> On Mon, 2020-09-14 at 17:12 -0700, Yu, Yu-cheng wrote: >>> On 9/14/2020 7:50 AM, Dave Hansen wrote: >>>> On 9/11/20 3:59 PM, Yu-cheng Yu wrote: >>>> ... >>>>> Here are the changes if we take the mprotect(PROT_SHSTK) approach. >>>>> Any comments/suggestions? >>>> I still don't like it. :) >>>> >>>> I'll also be much happier when there's a proper changelog to accompany >>>> this which also spells out the alternatives any why they suck so much. >> [...] >> >> I revised it. If this turns out needing more work/discussion, we can split it >> out from the shadow stack series. > > Where does that leave things? You only get shadow stacks for > single-threaded apps which have the ELF bits set? > As long as the system supports shadow stack, any application can mmap()/mprotect() a shadow stack. A pthread can allocate a shadow stack too. However, only shadow stack-enabled programs can activate/use the shadow stack.