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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A531EC3F2D7 for ; Thu, 5 Mar 2020 18:39:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 71E532072D for ; Thu, 5 Mar 2020 18:39:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71E532072D 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 11B596B0005; Thu, 5 Mar 2020 13:39:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A5636B0007; Thu, 5 Mar 2020 13:39:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ED6016B0008; Thu, 5 Mar 2020 13:39:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id D1C136B0005 for ; Thu, 5 Mar 2020 13:39:11 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id A32E7824805A for ; Thu, 5 Mar 2020 18:39:11 +0000 (UTC) X-FDA: 76562170902.13.guide04_502dc6681fe5c X-HE-Tag: guide04_502dc6681fe5c X-Filterd-Recvd-Size: 2868 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Mar 2020 18:39:10 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Mar 2020 10:39:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,518,1574150400"; d="scan'208";a="233019834" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by fmsmga007.fm.intel.com with ESMTP; 05 Mar 2020 10:39:09 -0800 Message-ID: <5dcc9da2caff92a9af16846cbe1f168f61368c51.camel@intel.com> Subject: Re: [RFC PATCH v9 18/27] x86/cet/shstk: Introduce WRUSS instruction From: Yu-cheng Yu To: Kees Cook Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , x86-patch-review@intel.com Date: Thu, 05 Mar 2020 10:39:08 -0800 In-Reply-To: <202002251309.E238DFEEB4@keescook> References: <20200205181935.3712-1-yu-cheng.yu@intel.com> <20200205181935.3712-19-yu-cheng.yu@intel.com> <202002251309.E238DFEEB4@keescook> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.4 (3.32.4-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit 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 Tue, 2020-02-25 at 13:10 -0800, Kees Cook wrote: > On Wed, Feb 05, 2020 at 10:19:26AM -0800, Yu-cheng Yu wrote: > > WRUSS is a new kernel-mode instruction but writes directly to user Shadow > > Stack (SHSTK) memory. This is used to construct a return address on SHSTK > > for the signal handler. > > > > This instruction can fault if the user SHSTK is not valid SHSTK memory. > > In that case, the kernel does a fixup. > > Since these functions aren't used in this patch, should this get merged > with patch 19? Yes, I can do that. Yu-cheng