Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757465Ab3HGUTS (ORCPT ); Wed, 7 Aug 2013 16:19:18 -0400 Received: from arkanian.console-pimps.org ([212.110.184.194]:43185 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756335Ab3HGUTR (ORCPT ); Wed, 7 Aug 2013 16:19:17 -0400 Date: Wed, 7 Aug 2013 21:19:08 +0100 From: Matt Fleming To: Andrew Fish Cc: edk2-devel@lists.sourceforge.net, Laszlo Ersek , linux-efi@vger.kernel.org, Gleb Natapov , lkml , David Woodhouse Subject: Re: [edk2] Corrupted EFI region Message-ID: <20130807201908.GG2515@console-pimps.org> References: <51FFC19A.1020204@redhat.com> <20130805161247.GF31845@pd.tnic> <51FFD5B0.9080000@redhat.com> <20130805164731.GG31845@pd.tnic> <52001896.1030509@redhat.com> <20130805220808.GC14067@pd.tnic> <20130806141036.GD14891@pd.tnic> <520116D1.2010000@redhat.com> <20130807151935.GJ17920@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 33 [ Readding Matthew Garrett to the Cc list, seeing as we both got removed for some unknown reason ] On Wed, 07 Aug, at 10:23:56AM, Andrew Fish wrote: > OK so I think I need some Cliff Notes here to help me understand what > is going on... > > type 4 is EfiBootServicesData and attr 0x0f is cache attributes with > no request for a runtime mapping. This is not runtime memory so to the > OS loader it is just memory EFI has used that will get freed back to > the OS after ExitBootServices(), along with EfiBootServicesCode, > EfiLoaderCode, and EfiLoaderData. The EfiLoaderCode and EfiLoaderData > also get freed back to the OS and they just exist for the convenience > of the OS loader. > > So I can't figure out why this maters? Given: We've seen a bunch of systems that make calls into EfiBootServicesCode after ExitBootServices(). There were some Apple machines in that list, though I don't have the details but Matthew should. So we map these regions unconditionally and in their original state, otherwise the firmware will generate fatal page faults when trying to access those memory regions. -- Matt Fleming, Intel Open Source Technology Center -- 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/