From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758198AbYC0JCl (ORCPT ); Thu, 27 Mar 2008 05:02:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755276AbYC0JCW (ORCPT ); Thu, 27 Mar 2008 05:02:22 -0400 Received: from relay2.sgi.com ([192.48.171.30]:59606 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754773AbYC0JCV (ORCPT ); Thu, 27 Mar 2008 05:02:21 -0400 Date: Thu, 27 Mar 2008 04:02:16 -0500 From: Paul Jackson To: Ingo Molnar Cc: ying.huang@intel.com, hpa@zytor.com, andi@firstfloor.org, mingo@redhat.com, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm 0/4] x86_64 boot: Add linked listof struct setup_data to boot protocol Message-Id: <20080327040216.99dcde7b.pj@sgi.com> In-Reply-To: <20080327083221.GD15626@elte.hu> References: <1206601743.3067.20.camel@caritas-dev.intel.com> <20080327083221.GD15626@elte.hu> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.12.0; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo asked: > what happens with the SGI machine Unless I misunderstand your post, Ingo, you don't need an SGI machine for this one, ... just a compiler ;). In the file arch/x86/boot/main.c, see the line: BUILD_BUG_ON(sizeof boot_params != 4096); This BUILD_BUG is serving as a reminder that the PC's "zero page", such as is encoded in the struct boot_params (include/asm-x86/bootparam.h) has to be exactly 4096 bytes by traditional PC architecture. One of the entries in that struct is: struct e820entry e820_map[E820MAX]; /* 0x2d0 */ H. Peter Anvin, Andi Kleen and Huang had further discussion in an earlier email thread as to how to best extend this limit. I trust that Huang's patch represents their concensus of that discussion. By the way, Peter, do you have any idea what that E820NR define is doing in include/asm-x86/e820.h ... it looks like useless redundancy to me? -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.940.382.4214