Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758741AbYH2RHp (ORCPT ); Fri, 29 Aug 2008 13:07:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756436AbYH2RHg (ORCPT ); Fri, 29 Aug 2008 13:07:36 -0400 Received: from terminus.zytor.com ([198.137.202.10]:46208 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756321AbYH2RHf (ORCPT ); Fri, 29 Aug 2008 13:07:35 -0400 Message-ID: <48B82BFD.5030807@zytor.com> Date: Fri, 29 Aug 2008 10:03:57 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Hugh Dickins CC: Jeremy Fitzhardinge , Ingo Molnar , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Alan Jenkins , Linux Kernel Mailing List Subject: Re: [PATCH RFC] x86: check for and defend against BIOS memory corruption References: <48B701FB.2020905@goop.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 835 Lines: 20 Hugh Dickins wrote: > > hpa introduced the 64k idea, and we've all been repeating it; > but I've not heard the reasoning behind it. Is it a fundamental > addressing limitation within the BIOS memory model? Or a case > that Windows treats the bottom 64k as scratch, so BIOS testers > won't notice if they corrupt it? > I should point out that I have seen one particular bug quite a few times poking around with boot loaders: the BIOS accesses memory at an otherwise valid address, but with the segment base set to either zero or 0x400 instead of whatever it should have been. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/