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 5F36DC433DB for ; Thu, 11 Mar 2021 15:44:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D025064FB8 for ; Thu, 11 Mar 2021 15:44:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D025064FB8 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 192BA8D02C7; Thu, 11 Mar 2021 10:44:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 16A4F8D02B2; Thu, 11 Mar 2021 10:44:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 031E78D02C7; Thu, 11 Mar 2021 10:44:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0107.hostedemail.com [216.40.44.107]) by kanga.kvack.org (Postfix) with ESMTP id DE2D88D02B2 for ; Thu, 11 Mar 2021 10:44:44 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A3AF33633 for ; Thu, 11 Mar 2021 15:44:44 +0000 (UTC) X-FDA: 77908016088.12.0C8CD41 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf21.hostedemail.com (Postfix) with ESMTP id D8BE7E0011C0 for ; Thu, 11 Mar 2021 15:44:40 +0000 (UTC) IronPort-SDR: 81zVEXqh/NL67A488f/1PHQOA/ErdSq4xDRjDbh154YZK6v1fLbpyFINCVZ5vQQcRTAChkJsP5 oM7Q2g0ofk+g== X-IronPort-AV: E=McAfee;i="6000,8403,9920"; a="175798706" X-IronPort-AV: E=Sophos;i="5.81,241,1610438400"; d="scan'208";a="175798706" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2021 07:44:40 -0800 IronPort-SDR: lVQmY3uuvk0SUoyAiiYU6+ijNeIsC7r6XEJxTl3KcWvFb7zk/HRdoWsUdZ7GfcLk9Ooudiw5o4 51RFWl0wayEQ== X-IronPort-AV: E=Sophos;i="5.81,241,1610438400"; d="scan'208";a="404106966" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.212.103.95]) ([10.212.103.95]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2021 07:44:39 -0800 Subject: Re: [PATCH v22 8/8] x86/vdso: Add ENDBR64 to __vdso_sgx_enter_enclave To: Peter Zijlstra , Jarkko Sakkinen 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 , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang References: <20210310220519.16811-1-yu-cheng.yu@intel.com> <20210310220519.16811-9-yu-cheng.yu@intel.com> <8b8efe44-b79f-ce29-ee28-066f88c93840@intel.com> From: "Yu, Yu-cheng" Message-ID: Date: Thu, 11 Mar 2021 07:44:39 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Stat-Signature: o1zes6aqmarabuthwga6etwr3q9bh3m9 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D8BE7E0011C0 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf21; identity=mailfrom; envelope-from=""; helo=mga02.intel.com; client-ip=134.134.136.20 X-HE-DKIM-Result: none/none X-HE-Tag: 1615477480-860447 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 3/11/2021 12:42 AM, Peter Zijlstra wrote: > On Thu, Mar 11, 2021 at 05:36:06AM +0200, Jarkko Sakkinen wrote: >> Does it do any harm to put it there unconditionally? > > Blows up your text footprint and I$ pressure. These instructions are 4 > bytes each. > > Aside from that, they're a NOP, so only consume front-end resources > (hopefully) on older CPUs and when IBT is disabled. > Thanks Peter. I think probably we'll do the macro Boris suggested. That takes care of the visual clutter, and eliminates the need of using .byte when the assembler is outdated. -- Yu-cheng