From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760096AbYFPIvU (ORCPT ); Mon, 16 Jun 2008 04:51:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754155AbYFPIvI (ORCPT ); Mon, 16 Jun 2008 04:51:08 -0400 Received: from mga11.intel.com ([192.55.52.93]:11184 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752484AbYFPIvF (ORCPT ); Mon, 16 Jun 2008 04:51:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.27,651,1204531200"; d="scan'208";a="578143079" Subject: Re: [PATCH 4/8] x86 boot: allow overlapping ebda and efi memmap memory ranges From: "Huang, Ying" To: Paul Jackson Cc: mingo@elte.hu, tglx@linutronix.de, yhlu.kernel@gmail.com, steiner@sgi.com, travis@sgi.com, hpa@zytor.com, linux-kernel@vger.kernel.org, andi@firstfloor.org, akpm@linux-foundation.org In-Reply-To: <20080616032457.718f4d87.pj@sgi.com> References: <20080616062945.14597.78009.sendpatchset@polaris-admin.engr.sgi.com> <20080616063001.14597.96170.sendpatchset@polaris-admin.engr.sgi.com> <1213600062.11185.13.camel@caritas-dev.intel.com> <20080616032457.718f4d87.pj@sgi.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Mon, 16 Jun 2008 16:53:55 +0800 Message-Id: <1213606435.12968.14.camel@caritas-dev.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.1 X-OriginalArrivalTime: 16 Jun 2008 08:50:58.0270 (UTC) FILETIME=[187537E0:01C8CF8E] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2008-06-16 at 03:24 -0500, Paul Jackson wrote: > Huang wrote: > > I think it is better to change boot loader to avoid memory area of EBDA. > > Would this require the bootloader to know the kernels rather arbitrary > heuristics for inventing and placing an EBDA area, in reserve_ebda_region()? I think it is sufficient for boot loader to avoid memory area from 0x9f000 to 0x100000. This can be seen as compatible code for legacy BIOS. > In general, I would think it better not to have to code into the EFI > firmware or bootloader such knowledge. But perhaps I am wrong here. > > If the kernel is going to reserve an EBDA region even if no EBDA is > requested by the BIOS, then I would think that the kernel should be > more tolerant of BIOS's that put something else in that place. > > > Or do not reserve EBDA on EFI system. > > I suppose. This would have been a bigger change than I could > suggest. For all I know, there are existing systems using EBDA > and EFI together. Would this change break them? > > If you have good reason to know that's essentially impossible then > I have no objections, so far as my needs go, to not reserving EBDA > on EFI systems. I think if EBDA area is used in EFI system, it should be reserved in EFI memory map. Best Regards, Huang Ying