Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937238AbXHHRS3 (ORCPT ); Wed, 8 Aug 2007 13:18:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763318AbXHHRSU (ORCPT ); Wed, 8 Aug 2007 13:18:20 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:54172 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763792AbXHHRST (ORCPT ); Wed, 8 Aug 2007 13:18:19 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Andi Kleen Cc: "Huang, Ying" , akpm@linux-foundation.org, Yinghai Lu , Randy Dunlap , Chandramouli Narayanan , linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] x86_64 EFI support -v3: EFI document References: <1185851583.23149.30.camel@caritas-dev.intel.com> <200708081208.01080.ak@suse.de> <200708081822.07758.ak@suse.de> Date: Wed, 08 Aug 2007 11:17:18 -0600 In-Reply-To: <200708081822.07758.ak@suse.de> (Andi Kleen's message of "Wed, 8 Aug 2007 18:22:07 +0200") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1387 Lines: 41 Andi Kleen writes: >> >> This is the classic skip the 16bit code and enter the kernel >> in 32bit mode filling in the fields that the 16bit mode code would >> have filled in the same way approach. > > kexec can use it because it's in tree. Not the part that actually uses it. > But I don't think using it by out of tree stuff is a good idea. > > e.g. assuming we need a new field. How would we extend this? > There is no version number or anything to detect this. > > For in tree code it can be just updated. But weirdo-EFI-boot loader > cannot. So far the logic has been. Inspect bzImage. And get boot protocol version. If field we need for returning data is not supported do not give data. Or something like that. Usually the fields always exist and you can just fill them in and we only append to the boot protocol structure. In practice this has been working for the last 7 years or so, for EFI, and LinuxBIOS, and kexec, and Gujin and I don't remember what else. It isn't the prettiest thing in the world but it works and everybody who needs it uses it. Which tend to be the important parts for a standard. Eric - 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/