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=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham 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 64C9FC64E7B for ; Mon, 30 Nov 2020 19:56:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DC8220679 for ; Mon, 30 Nov 2020 19:56:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Kngn4LeL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727942AbgK3T4p (ORCPT ); Mon, 30 Nov 2020 14:56:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726769AbgK3T4p (ORCPT ); Mon, 30 Nov 2020 14:56:45 -0500 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D134C0613D2 for ; Mon, 30 Nov 2020 11:56:05 -0800 (PST) Received: by mail-pj1-x1049.google.com with SMTP id e21so251148pjh.5 for ; Mon, 30 Nov 2020 11:56:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=DLtArDV8cKP0BeVklsVGWZ4r7522fWxRlpZkbLI2DME=; b=Kngn4LeLTwq4qYdSAXMCdhjRvG2+hfAwezvYYxclNLH4UYmaXcHHHm/oDA7haEQqo5 cDgZ9CTL0bEBGcADB4JOqwDiXbdJifF4LwJgDbjttt2y9O+5miEIVUz2RYOGgeK4NbXj AZHT/WuYNGIuZ+g8cSddgDUX/X/wdLKAeH5yE1Nh6rDk+ejhrEqeGQWhdv05kN+gQ9Uh oOmj6zDFqIWJQpVkAoxeNann4anzRJS+12uX8GB2/354ozUtuLyoprqIvdEFHrYVQBXR J0hiCEXvI45QzTD2c934ITS2t0agvN8pr8586/Tl43yb3ixwscsBmaJeFId+9Gzx78bV bteQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=DLtArDV8cKP0BeVklsVGWZ4r7522fWxRlpZkbLI2DME=; b=qJRJ+w57enxxxTyQrsPv6n6i1YKtzNEMISudLPUCxVGQqwXpmGBPHNC7F9hma6+lMf SeW6rTov2n447szsoaVw4j/BLwrefpgQaJI3jwZXW8SkJM8h60fU3oIjde8W5W3+Bjf3 YC3GvFM/vd9cyqdJlnuziocUEIxwMaw0dJ9OAT/LLyXgiN/kOvfShClL2KPW+O2Aho/K zSShwoAG88Ge7mzDW2KuT5Tv0EPgmEPnpZt9UA3Fbg6GMQnNJfBsDaz5Pw6MksrRXsNe nHcygekBY0tm5YwzWHsZW/aKXylRnaDLcvGUbOz9rUTrX0+uGY4xLdhACnmYm9saSFsS 4WoQ== X-Gm-Message-State: AOAM532RTOfVxwsLvgjwHM1PJ5z83U/NsZHpAhN2y3AeGafoCJBvh5vw fnlDkWI9KIWvge537H/BPPpRkTMjcsCve1YkYrs= X-Google-Smtp-Source: ABdhPJzB688RhMdWZtegBv6aVz52FbjVdJ0Q+QuBT876w4Q6KmkjclwwABgZ0Hd+nwZUsJGEaNoSrmQC9+tOAwhsDUU= Sender: "ndesaulniers via sendgmr" X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:4d25]) (user=ndesaulniers job=sendgmr) by 2002:a17:90a:f28f:: with SMTP id fs15mr495886pjb.121.1606766164462; Mon, 30 Nov 2020 11:56:04 -0800 (PST) Date: Mon, 30 Nov 2020 11:56:02 -0800 In-Reply-To: <20201110162211.9207-6-yu-cheng.yu@intel.com> Message-Id: <20201130195602.331842-1-ndesaulniers@google.com> Mime-Version: 1.0 References: <20201110162211.9207-6-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: Re: [PATCH v15 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack From: Nick Desaulniers To: yu-cheng.yu@intel.com Cc: Dave.Martin@arm.com, arnd@arndb.de, bp@alien8.de, bsingharora@gmail.com, corbet@lwn.net, dave.hansen@linux.intel.com, esyr@redhat.com, fweimer@redhat.com, gorcunov@gmail.com, hjl.tools@gmail.com, hpa@zytor.com, jannh@google.com, keescook@chromium.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, mike.kravetz@oracle.com, mingo@redhat.com, nadav.amit@gmail.com, oleg@redhat.com, pavel@ucw.cz, pengfei.xu@intel.com, peterz@infradead.org, ravi.v.shankar@intel.com, rdunlap@infradead.org, tglx@linutronix.de, vedvyas.shanbhogue@intel.com, weijiang.yang@intel.com, x86@kernel.org, Sami Tolvanen , Will Deacon , Masahiro Yamada Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org In response to https://lore.kernel.org/lkml/20201110162211.9207-6-yu-cheng.yu@intel.com/. Hi Yu-cheng, This feature reminds me very much of ARCH_SUPPORTS_SHADOW_CALL_STACK/CC_HAVE_SHADOW_CALL_STACK implemented in https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5287569a790d2546a06db07e391bf84b8bd6cf51. Do you think it would be worthwhile to share the same config name between x86 and aarch64? (Though, it seems on x86 there will be a distinction between kernel mode and user mode configs, if I understand correctly?)