From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754527Ab1KGUgl (ORCPT ); Mon, 7 Nov 2011 15:36:41 -0500 Received: from terminus.zytor.com ([198.137.202.10]:45190 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453Ab1KGUgk (ORCPT ); Mon, 7 Nov 2011 15:36:40 -0500 Message-ID: <4EB8413D.6030500@zytor.com> Date: Mon, 07 Nov 2011 12:36:13 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0) Gecko/20110927 Thunderbird/7.0 MIME-Version: 1.0 To: Matthew Garrett CC: Matt Fleming , Thomas Gleixner , Ingo Molnar , Zhang Rui , Huang Ying , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] x86, efi: Calling __pa() with an ioremap'd address is invalid References: <1320680088-2584-1-git-send-email-matt@console-pimps.org> <20111107202324.GA27515@srcf.ucam.org> In-Reply-To: <20111107202324.GA27515@srcf.ucam.org> X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/07/2011 12:23 PM, Matthew Garrett wrote: > On Mon, Nov 07, 2011 at 03:34:48PM +0000, Matt Fleming wrote: > >> After the feedback from v1 I tried to unify the efi_ioremap() >> implementations but ran into the issue detailed in the RH bug report >> in the changelog. Unless we teach the x86 setup code that >> EFI_RUNTIME_SERVICES_DATA regions should be part of the direct kernel >> mapping table (even though they're marked as E820_RESERVED) I think >> this patch makes the most sense. > > Honestly it seems like there may well be an argument for that. We're > talking about executable code that the kernel will be calling - it seems > theoretically neater for it to be added to the direct mapping. We're > just heavily constrained by our collapsing of the EFI memory map onto > the rather less fine-grained E820 one and the lack of any obvious way to > extend that in an OS-specific manner. I guess we could expect the > bootloader to conform to the standard and then re-walk the EFI memory > map ourselves to fix things up, but eww... > Yes, I think it makes a lot of sense. If we need to introduce new meta-types to deal with the fact that there are EFI types that don't map to E820, then so be it... and this is *exactly* why we want the EFI setup stub to be part of the kernel image and not off in a separate bootloader, requiring a stable interface... -hpa