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=-10.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 EE5DDC433E2 for ; Tue, 1 Sep 2020 06:23:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CAA9D2071B for ; Tue, 1 Sep 2020 06:23:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726654AbgIAGXL (ORCPT ); Tue, 1 Sep 2020 02:23:11 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:43486 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726006AbgIAGXL (ORCPT ); Tue, 1 Sep 2020 02:23:11 -0400 X-IronPort-AV: E=Sophos;i="5.76,378,1592841600"; d="scan'208";a="98763069" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 01 Sep 2020 14:23:04 +0800 Received: from G08CNEXMBPEKD06.g08.fujitsu.local (unknown [10.167.33.206]) by cn.fujitsu.com (Postfix) with ESMTP id 6B6A748990DC; Tue, 1 Sep 2020 14:23:01 +0800 (CST) Received: from [10.167.226.60] (10.167.226.60) by G08CNEXMBPEKD06.g08.fujitsu.local (10.167.33.206) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 1 Sep 2020 14:23:00 +0800 Subject: Re: [PATCH] Documentation/x86/boot.rst: minor improvement To: "H. Peter Anvin" , , , CC: , , , References: <20200901034157.5482-1-caoj.fnst@cn.fujitsu.com> <2cb35238-0008-4a89-7abf-8045bd753728@zytor.com> From: Cao jin Message-ID: <2486ec9a-64fe-6026-274d-4afa3548273f@cn.fujitsu.com> Date: Tue, 1 Sep 2020 14:23:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <2cb35238-0008-4a89-7abf-8045bd753728@zytor.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.226.60] X-ClientProxiedBy: G08CNEXCHPEKD05.g08.fujitsu.local (10.167.33.203) To G08CNEXMBPEKD06.g08.fujitsu.local (10.167.33.206) X-yoursite-MailScanner-ID: 6B6A748990DC.AB144 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: caoj.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/1/20 1:35 PM, H. Peter Anvin wrote: > If you are going to fix the language... > > On 2020-08-31 22:25, Cao jin wrote: >> Sorry, I mis-copied 2 addresses. make sure they are CCed. >> >> On 9/1/20 11:41 AM, Cao jin wrote: >>> Typo fix & file name update >>> I did quick search in dict & google, didn't see ident = identity, my omission. >>> Signed-off-by: Cao jin ... >>> @@ -1391,7 +1391,7 @@ In 64-bit boot protocol, the kernel is started by jumping to the >>> >>> At entry, the CPU must be in 64-bit mode with paging enabled. > > (Paging enabled is redundant here.) Yes, 64-bit defaults with paging enabled. Maybe it is a little bit helpful for newbies. > >>> The range with setup_header.init_size from start address of loaded >>> -kernel and zero page and command line buffer get ident mapping; >>> +kernel and zero page and command line buffer get identity mapping; > > The range with setup_header.init_size from start address of the loaded kernel, > the zero page, and the command line buffer get identity-mapped, anda GDT must > be loaded with the descriptors for selectors __BOOT_CS(0x10) and > __BOOT_DS(0x18): both descriptors must be 4G flat segment with __BOOT_CS > having execute/read > permission and __BOOT_DS... > > Also, it might be useful to take a look to see if other data structures, like > setup_data and the initrd also need to be in the identity map. > Thanks for your info. I have indistinct memory that KASLR need them identity mapped. I will take a look. -- Sincerely, Cao jin