From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757875Ab1KKNtj (ORCPT ); Fri, 11 Nov 2011 08:49:39 -0500 Received: from arkanian.console-pimps.org ([212.110.184.194]:40516 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752678Ab1KKNti (ORCPT ); Fri, 11 Nov 2011 08:49:38 -0500 Subject: Re: [PATCH v3] x86, efi: Calling __pa() with an ioremap'd address is invalid From: Matt Fleming To: huang ying Cc: Matthew Garrett , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Zhang Rui , linux-kernel@vger.kernel.org In-Reply-To: <1321017132.3572.196.camel@mfleming-mobl1.ger.corp.intel.com> References: <1320680088-2584-1-git-send-email-matt@console-pimps.org> <20111107202324.GA27515@srcf.ucam.org> <1321017132.3572.196.camel@mfleming-mobl1.ger.corp.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 11 Nov 2011 13:49:35 +0000 Message-ID: <1321019375.3572.200.camel@mfleming-mobl1.ger.corp.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-11-11 at 13:12 +0000, Matt Fleming wrote: > On Fri, 2011-11-11 at 09:02 +0800, huang ying wrote: > > On Tue, Nov 8, 2011 at 4:23 AM, 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... > > > > Sorry for late. > > > > Why ioremap_cache() can not work for some EFI_RUNTIME_SERVICES_DATA region? > > It looks like ioremap_cache() maps the region with the NX bit set. Sorry, ignore this nonsensical answer, obviously we shouldn't be executing data. Honestly, I'm not sure why it doesn't work. -- Matt Fleming, Intel Open Source Technology Center