From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754046Ab1KGUXy (ORCPT ); Mon, 7 Nov 2011 15:23:54 -0500 Received: from cavan.codon.org.uk ([93.93.128.6]:49480 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754156Ab1KGUXw (ORCPT ); Mon, 7 Nov 2011 15:23:52 -0500 Date: Mon, 7 Nov 2011 20:23:24 +0000 From: Matthew Garrett To: Matt Fleming Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Zhang Rui , Huang Ying , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] x86, efi: Calling __pa() with an ioremap'd address is invalid Message-ID: <20111107202324.GA27515@srcf.ucam.org> References: <1320680088-2584-1-git-send-email-matt@console-pimps.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1320680088-2584-1-git-send-email-matt@console-pimps.org> User-Agent: Mutt/1.5.20 (2009-06-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@cavan.codon.org.uk X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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... -- Matthew Garrett | mjg59@srcf.ucam.org