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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 12A46C43467 for ; Mon, 12 Oct 2020 19:15:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6CCD7221EB for ; Mon, 12 Oct 2020 19:15:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ql1melcR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CCD7221EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6FF596B005D; Mon, 12 Oct 2020 15:15:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6ADFB6B0062; Mon, 12 Oct 2020 15:15:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5506C6B0068; Mon, 12 Oct 2020 15:15:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0155.hostedemail.com [216.40.44.155]) by kanga.kvack.org (Postfix) with ESMTP id 295FD6B005D for ; Mon, 12 Oct 2020 15:15:17 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B67A68249980 for ; Mon, 12 Oct 2020 19:15:16 +0000 (UTC) X-FDA: 77364226632.30.rifle48_0216e8d271fd Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 8BCA0180B3C85 for ; Mon, 12 Oct 2020 19:15:16 +0000 (UTC) X-HE-Tag: rifle48_0216e8d271fd X-Filterd-Recvd-Size: 4748 Received: from mail-lj1-f196.google.com (mail-lj1-f196.google.com [209.85.208.196]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Mon, 12 Oct 2020 19:15:15 +0000 (UTC) Received: by mail-lj1-f196.google.com with SMTP id i2so17961443ljg.4 for ; Mon, 12 Oct 2020 12:15:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=HoEgSi7W4gHD9lScysoMmzA283msUCELsQqu811nuNc=; b=Ql1melcRhvWByESFg5O9z6kB9ZaejNEcoZdrPtWcHm5Eb+e5dEy98OHoHK4KMI2qvs BQbhmbBhTukGkR6Q48H5ZM27KZKnMeP2hVXC0TSoA+qQvkm9o8wE/+LF1rVnj/ar4xAF Qror7GlA7bJ2bzmz2QWfUBs8yBTTNxkCL0HpPmUzKqOhaDoa6qRTCjs8xGcriqroLZAR V76TOINy7/Wulmj/k/4QrmvLbA9NzyHoH/vyZUqRMQ8pMYwL1LPGHQswhd0jwVv+3eSy bVo9G1b4xp9hb1TemZo1b/eBszcC0Kc+o3gaCGKztpcU+AG/e+dFRg+PlwYmkACn1S5I Tc/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=HoEgSi7W4gHD9lScysoMmzA283msUCELsQqu811nuNc=; b=GnlNthQpHd7yKQbgHdA1foJkpRV8lpsXuck3mn2Dt64/d20n1QJrTPrjpV3TeVM5qC S8GuLyYxQ7wE+nKn0bLQN+6jttgJyzMqOuX6bTv4lhAnFzFdLzchYCs+hKEi9kgIWcuv 4vAfV+Bw+kKRyGpj1VYYYGXF+oapEaFm8MwLKUSmm+Mu8SHfWGIf0eP+b/EGFzzG5Pmx 05heJ+pNk6WYMeItfMAf4VsWFBgsB8OLy+wllQZVhsbufMDm3XtbWgXSftxMSjtRewQl ap5kt3aora2X7GwJxHJbJYqxeSCjuiQtY6VdNobJSH0Iqen7ovpWnJMXhtQCPbbHEAyv +evw== X-Gm-Message-State: AOAM532qaCa43erEPwFSpPmgb7kMq1+UQ8GXS+UqVorRzUY4GoiTxnJH J8hkND6AP0npHkTYUFU0ACU= X-Google-Smtp-Source: ABdhPJyunP+sr/B3JWabN71d6meVGuLl7M/RSAPI9eowpJdSxaoXQ/4ExdCfDtrOaJiRLT2GklJNOQ== X-Received: by 2002:a2e:a41a:: with SMTP id p26mr3102963ljn.126.1602530114236; Mon, 12 Oct 2020 12:15:14 -0700 (PDT) Received: from grain.localdomain ([5.18.102.224]) by smtp.gmail.com with ESMTPSA id q27sm1092814lfd.261.2020.10.12.12.15.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Oct 2020 12:15:13 -0700 (PDT) Received: by grain.localdomain (Postfix, from userid 1000) id 0C3381A032A; Mon, 12 Oct 2020 22:15:11 +0300 (MSK) Date: Mon, 12 Oct 2020 22:15:11 +0300 From: Cyrill Gorcunov To: Yu-cheng Yu 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 , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu Subject: Re: [PATCH v14 1/7] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking Message-ID: <20201012191511.GC14048@grain> References: <20201012154530.28382-1-yu-cheng.yu@intel.com> <20201012154530.28382-2-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012154530.28382-2-yu-cheng.yu@intel.com> User-Agent: Mutt/1.14.6 (2020-07-11) 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 Mon, Oct 12, 2020 at 08:45:24AM -0700, Yu-cheng Yu wrote: ... > + the application support it. When this feature is enabled, > + legacy non-IBT applications continue to work, but without > + IBT protection. > + Support for this feature is only known to be present on > + processors released in 2020 or later. CET features are also > + known to increase kernel text size by 3.7 KB. It seems the last sentence is redundant - new features always bloat the kernel code and precise size may differ depending on compiler and options. Surely this can be patched on top.