From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754882AbXJWWQU (ORCPT ); Tue, 23 Oct 2007 18:16:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752571AbXJWWQM (ORCPT ); Tue, 23 Oct 2007 18:16:12 -0400 Received: from terminus.zytor.com ([198.137.202.10]:43099 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752564AbXJWWQL (ORCPT ); Tue, 23 Oct 2007 18:16:11 -0400 Message-ID: <471E729F.3000105@zytor.com> Date: Tue, 23 Oct 2007 15:15:59 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: "Huang, Ying" , Andi Kleen , "Eric W. Biederman" , akpm@linux-foundation.org, Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: [PATCH -v7 1/3] x86 boot: setup data References: <1193126771.23935.79.camel@caritas-dev.intel.com> <471E70E0.2090802@goop.org> In-Reply-To: <471E70E0.2090802@goop.org> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: >> 1: >> + movl boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER,%ebp > > You need to check the boot protocol version before looking at this pointer. > No, he doesn't. The boot protocol version is communication between the boot loader and the kernel (specifically, it is communication FROM the kernel TO the bootloader), not between internal bits of the kernel. Th Since the pointer is safely inside the setup template, even if the bootloader doesn't understand boot protocol version 2.08 it will have copied it. So this is fine. -hpa