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 59C8AC433ED for ; Thu, 20 May 2021 00:18:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F9FE610CD for ; Thu, 20 May 2021 00:18:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230097AbhETAUS (ORCPT ); Wed, 19 May 2021 20:20:18 -0400 Received: from mga03.intel.com ([134.134.136.65]:46428 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229598AbhETAUQ (ORCPT ); Wed, 19 May 2021 20:20:16 -0400 IronPort-SDR: 2kY2YYEwc6Atwmluj8vIhbh5MjvhwCRUg3lPlnkhVyTEqv/zas1mFOT2GigGU6WPs6TPR/DDXC 0mTyrZyQ7lag== X-IronPort-AV: E=McAfee;i="6200,9189,9989"; a="201165398" X-IronPort-AV: E=Sophos;i="5.82,313,1613462400"; d="scan'208";a="201165398" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2021 17:18:56 -0700 IronPort-SDR: qj58NiAbcEmWTXcMXiYlqnmWgBe2IyOSLo3brLbpWiHwJzDbexLYODcDCUZ05v8EeaF5//FeSe LFciUtsU1x0A== X-IronPort-AV: E=Sophos;i="5.82,313,1613462400"; d="scan'208";a="411959002" Received: from ccheung-mobl.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.212.97.108]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2021 17:18:54 -0700 Subject: Re: [RFC v2-fix 1/1] x86/boot: Add a trampoline for APs booting in 64-bit mode To: Dan Williams Cc: Peter Zijlstra , Andy Lutomirski , Dave Hansen , Tony Luck , Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , Linux Kernel Mailing List , Sean Christopherson , Kai Huang References: <20210518005404.258660-1-sathyanarayanan.kuppuswamy@linux.intel.com> <861a316c-09f6-5969-6238-e402fca917db@linux.intel.com> From: "Kuppuswamy, Sathyanarayanan" Message-ID: Date: Wed, 19 May 2021 17:18:52 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dan, On 5/17/21 9:08 PM, Dan Williams wrote: >> SYM_DATA_START_LOCAL(tr_idt) >> .short 0 >> .quad 0 >> SYM_DATA_END(tr_idt) > This format implies that tr_idt is reserving space for 2 distinct data > structure attributes of those sizes, can you just put those names here > as comments? Otherwise the .fill format is more compact. Initially its 6 bytes (2 bytes for IDT limit, 4 bytes for 32 bit linear start address). This patch extends it by another 4 bytes for supporting 64 bit mode. 2 bytes IDT limit (.short) 8 bytes for 64 bit IDT start address (.quad) This info is included in commit log. But I will add comment here as you have mentioned. Will following comment log do ? /* Use 10 bytes for IDT (in 64 bit mode), 8 bytes for IDT start address 2 bytes for IDT limit size */ -- Sathyanarayanan Kuppuswamy Linux Kernel Developer