From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BBA5C43A1D for ; Thu, 12 Jul 2018 13:31:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EA93213A2 for ; Thu, 12 Jul 2018 13:31:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5EA93213A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732411AbeGLNlN (ORCPT ); Thu, 12 Jul 2018 09:41:13 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:51032 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726782AbeGLNlN (ORCPT ); Thu, 12 Jul 2018 09:41:13 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E35A180D; Thu, 12 Jul 2018 06:31:38 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B366F3F5B1; Thu, 12 Jul 2018 06:31:38 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id F04E11AE53FB; Thu, 12 Jul 2018 14:32:20 +0100 (BST) Date: Thu, 12 Jul 2018 14:32:20 +0100 From: Will Deacon To: Ard Biesheuvel Cc: James Morse , AKASHI Takahiro , Catalin Marinas , "Baicar, Tyler" , Bhupesh Sharma , Dave Young , Mark Rutland , Al Stone , Graeme Gregory , Hanjun Guo , Lorenzo Pieralisi , Sudeep Holla , linux-arm-kernel , Linux Kernel Mailing List , Kexec Mailing List Subject: Re: [PATCH v3.1 2/4] efi/arm: preserve early mapping of UEFI memory map longer for BGRT Message-ID: <20180712133220.GA21647@arm.com> References: <20180709234229.20181-1-takahiro.akashi@linaro.org> <20180709234229.20181-3-takahiro.akashi@linaro.org> <93c42065-bece-a4c7-ed99-5e98f91315a6@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 10, 2018 at 08:39:16PM +0200, Ard Biesheuvel wrote: > On 10 July 2018 at 19:57, James Morse wrote: > > Hi Ard, > > > > On 10/07/18 00:42, AKASHI Takahiro wrote: > >> From: Ard Biesheuvel > >> > >> The BGRT code validates the contents of the table against the UEFI > >> memory map, and so it expects it to be mapped when the code runs. > >> > >> On ARM, this is currently not the case, since we tear down the early > >> mapping after efi_init() completes, and only create the permanent > >> mapping in arm_enable_runtime_services(), which executes as an early > >> initcall, but still leaves a window where the UEFI memory map is not > >> mapped. > >> > >> So move the call to efi_memmap_unmap() from efi_init() to > >> arm_enable_runtime_services(). > > > > I don't have a machine that generates a BGRT, but I can see that efi_mem_type() > > call in efi_bgrt_init() would cause the same problems we have with kexec and acpi. > > > > I'm not sure I follow. The BGRT table only contains natively aligned > fields, so the alignment faults should not occur when accessing this > table after kexec. The issue addressed by this patch is that > efi_mem_type() bails when called while EFI_MEMMAP is cleared. > > > > >> diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c > >> index b5214c143fee..388a929baf95 100644 > >> --- a/drivers/firmware/efi/arm-init.c > >> +++ b/drivers/firmware/efi/arm-init.c > >> @@ -259,7 +259,6 @@ void __init efi_init(void) > >> > >> reserve_regions(); > >> efi_esrt_init(); > >> - efi_memmap_unmap(); > >> > >> memblock_reserve(params.mmap & PAGE_MASK, > >> PAGE_ALIGN(params.mmap_size + > >> diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c > >> index 5889cbea60b8..59a8c0ec94d5 100644 > >> --- a/drivers/firmware/efi/arm-runtime.c > >> +++ b/drivers/firmware/efi/arm-runtime.c > >> @@ -115,6 +115,8 @@ static int __init arm_enable_runtime_services(void) > >> return 0; > >> } > >> > >> + efi_memmap_unmap(); > > > > This can get called twice if uefi_init() fails after setting the EFI_BOOT flag, > > but this can only happen if the system table signature is wrong, (or we're out > > of memory really early). > > > > I guess we should check the EFI_MEMMAP attribute here as well then. Do you plan to spin a new version of this patch? Will