Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752748AbdHDMLn (ORCPT ); Fri, 4 Aug 2017 08:11:43 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:36111 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752367AbdHDMGx (ORCPT ); Fri, 4 Aug 2017 08:06:53 -0400 Date: Fri, 4 Aug 2017 13:06:50 +0100 From: Matt Fleming To: Stuart Hayes Cc: Ard Biesheuvel , "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH] x86/efi: page align EFI ROM image ranges Message-ID: <20170804120650.GE8187@codeblueprint.co.uk> References: <4a28637c-d5ff-95ed-5bee-2b1e465f2d79@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4a28637c-d5ff-95ed-5bee-2b1e465f2d79@gmail.com> User-Agent: Mutt/1.5.24+42 (6e565710a064) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3815 Lines: 82 On Wed, 02 Aug, at 11:41:38AM, Stuart Hayes wrote: > (Resend because I mistyped the maintainer's email address the first time.) > > The kernel's EFI stub locates and copies EFI ROM images into memory, > which it allocates using the byte-granular EFI allocate_pool > function. These memory ranges are then added to setup_data, and > later to e820 (in e820__reserve_setup_data()). The e820 ranges are > parsed to create nosave regions (in > e820__register_nosave_regions()), but when non-page-aligned e820 > regions are parsed, a nosave page is added at the beginning and end > of each non-page-aligned region, which results in data not getting > saved or restored during a hibernate/resume. This can result in > random failures after a hibernate/resume. > > Round up the allocation size to a whole number of pages, and use EFI > allocate_pages to ensure that the EFI ROM copy regions are > page-aligned. > > On a system with six EFI ROM images, before the patch: > > e820: update [mem 0x64866020-0x6486e05f] usable ==> usable > e820: update [mem 0x6147a020-0x61499c5f] usable ==> usable > e820: update [mem 0x60fff020-0x6105785f] usable ==> usable > e820: update [mem 0x60fa6020-0x60ffe85f] usable ==> usable > e820: update [mem 0x60f4d020-0x60fa585f] usable ==> usable > e820: update [mem 0x60ef4020-0x60f4c85f] usable ==> usable > ... > PM: Registered nosave memory: [mem 0x00000000-0x00000fff] > PM: Registered nosave memory: [mem 0x000a0000-0x000fffff] > PM: Registered nosave memory: [mem 0x60ef4000-0x60ef4fff] > PM: Registered nosave memory: [mem 0x60f4c000-0x60f4cfff] > PM: Registered nosave memory: [mem 0x60f4d000-0x60f4dfff] > PM: Registered nosave memory: [mem 0x60fa5000-0x60fa5fff] > PM: Registered nosave memory: [mem 0x60fa6000-0x60fa6fff] > PM: Registered nosave memory: [mem 0x60ffe000-0x60ffefff] > PM: Registered nosave memory: [mem 0x60fff000-0x60ffffff] > PM: Registered nosave memory: [mem 0x61057000-0x61057fff] > PM: Registered nosave memory: [mem 0x6147a000-0x6147afff] > PM: Registered nosave memory: [mem 0x61499000-0x61499fff] > PM: Registered nosave memory: [mem 0x64866000-0x64866fff] > PM: Registered nosave memory: [mem 0x6486e000-0x6486efff] > PM: Registered nosave memory: [mem 0x6cf6e000-0x6f3ccfff] > > After the patch: > > e820: update [mem 0x64866000-0x6486efff] usable ==> usable > e820: update [mem 0x6147a000-0x61499fff] usable ==> usable > e820: update [mem 0x60fff000-0x61057fff] usable ==> usable > e820: update [mem 0x60fa6000-0x60ffefff] usable ==> usable > e820: update [mem 0x60f4d000-0x60fa5fff] usable ==> usable > e820: update [mem 0x60ef4000-0x60f4cfff] usable ==> usable > ... > PM: Registered nosave memory: [mem 0x00000000-0x00000fff] > PM: Registered nosave memory: [mem 0x000a0000-0x000fffff] > PM: Registered nosave memory: [mem 0x6cf6e000-0x6f3ccfff] > > Signed-off-by: Stuart Hayes > --- > > --- linux-4.13-rc2/arch/x86/boot/compressed/eboot.c.orig 2017-08-01 12:12:04.696049106 -0400 > +++ linux-4.13-rc2/arch/x86/boot/compressed/eboot.c 2017-08-01 12:11:33.120182236 -0400 > @@ -235,7 +235,12 @@ __setup_efi_pci64(efi_pci_io_protocol_64 > > size = pci->romsize + sizeof(*rom); > > - status = efi_call_early(allocate_pool, EFI_LOADER_DATA, size, &rom); > + /* > + * Get whole pages because this will be added to e820. > + */ > + size = PAGE_ALIGN(size); > + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ANY_PAGES, > + EFI_LOADER_DATA, (size >> PAGE_SHIFT), &rom); > if (status != EFI_SUCCESS) { > efi_printk(sys_table, "Failed to alloc mem for rom\n"); > return status; > Nice catch. The comment could do with a little more information, including the fact that it's the e820 nosave code that expects page-aligned ROM regions. Also, you'll need the same fix for __setup_efi_pci32().