From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756175AbXI1W3R (ORCPT ); Fri, 28 Sep 2007 18:29:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753478AbXI1W3B (ORCPT ); Fri, 28 Sep 2007 18:29:01 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55541 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753182AbXI1W3A (ORCPT ); Fri, 28 Sep 2007 18:29:00 -0400 Message-ID: <46FD8003.7090902@zytor.com> Date: Fri, 28 Sep 2007 15:28:19 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: "Huang, Ying" CC: Andi Kleen , "Eric W. Biederman" , akpm@linux-foundation.org, Yinghai Lu , Chandramouli Narayanan , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm -v3 1/2] i386/x86_64 boot: setup data References: <1190192306.12429.76.camel@caritas-dev.intel.com> <46F14896.8080603@zytor.com> <1190873200.21818.292.camel@caritas-dev.intel.com> In-Reply-To: <1190873200.21818.292.camel@caritas-dev.intel.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Huang, Ying wrote: > Hi, Peter, > > On Wed, 2007-09-19 at 09:04 -0700, H. Peter Anvin wrote: >> Huang, Ying wrote: >>> Known Issues: >>> >>> 1. Where is safe to place the linked list of setup_data? >>> Because the length of the linked list of setup_data is variable, it >>> can not be copied into BSS segment of kernel as that of "zero >>> page". We must find a safe place for it, where it will not be >>> overwritten by kernel during booting up. The i386 kernel will >>> overwrite some pages after _end. The x86_64 kernel will overwrite some >>> pages from 0x1000 on. >>> >> The latter is definitely not safe, since the space below 640K is the >> documented place to put the command line (and presumably where the >> bootloader would put other auxilliary chunks.) >> >> I'll try to do a full review of this later today. Haven't had time yet >> to look at this anything than but piecemeal. > > Do you think this patch and the 32-bit boot protocol patch are ready to > merge for -mm? If not, I can revise them. > Sorry, haven't had a chance to look at it in proper detail yet, mostly due to debugging, but one thing I'd like to see is both the boot_params structure as well as all the chained information pointers exported into sysfs. The experience with the x86 setup code has shown that it would help immensely with debugging, not to mention being available to tools like kexec. -hpa