From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753064AbYEYEHN (ORCPT ); Sun, 25 May 2008 00:07:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750898AbYEYEHB (ORCPT ); Sun, 25 May 2008 00:07:01 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55512 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760AbYEYEHA (ORCPT ); Sun, 25 May 2008 00:07:00 -0400 Message-ID: <4838E5D4.4050708@zytor.com> Date: Sat, 24 May 2008 21:06:44 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Rik van Riel CC: =?ISO-8859-1?Q?Kristian_H=F8gsberg?= , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] Use structs instead of hardcoded offsets in x86 boot decompressor. References: <1211579968-15227-1-git-send-email-krh@redhat.com> <20080523210744.52fe7fde@bree.surriel.com> <4837B2DD.908@zytor.com> <20080525000330.3eedd788@riellaptop.surriel.com> In-Reply-To: <20080525000330.3eedd788@riellaptop.surriel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rik van Riel wrote: > On Fri, 23 May 2008 23:17:01 -0700 > "H. Peter Anvin" wrote: > >> Uhm... except it doesn't live at address zero, at all. >> >> It's called "zeropage" because we used to recycle it into >> empty_zero_page, a long long time ago. >> >> The bootparms structure is pointed to by %esi being passed from the >> setup code to the decompressor to the kernel. > > Then why does dereferencing the uninitialized > pointer work, both in the code before and after > the patch? > > What am I misssing? Heck if I know. It definitely *shouldn't* work... -hpa