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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 C48D1C3279B for ; Tue, 10 Jul 2018 18:43:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9216D20B6F for ; Tue, 10 Jul 2018 18:43:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9216D20B6F 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 S2389569AbeGJSnt (ORCPT ); Tue, 10 Jul 2018 14:43:49 -0400 Received: from foss.arm.com ([217.140.101.70]:51804 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389001AbeGJSdm (ORCPT ); Tue, 10 Jul 2018 14:33:42 -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 DE6591BA8; Tue, 10 Jul 2018 10:57:36 -0700 (PDT) Received: from [10.1.206.34] (melchizedek.cambridge.arm.com [10.1.206.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2937F3F589; Tue, 10 Jul 2018 10:57:33 -0700 (PDT) Subject: Re: [PATCH v3.1 2/4] efi/arm: preserve early mapping of UEFI memory map longer for BGRT To: ard.biesheuvel@linaro.org Cc: AKASHI Takahiro , catalin.marinas@arm.com, will.deacon@arm.com, tbaicar@codeaurora.org, bhsharma@redhat.com, dyoung@redhat.com, mark.rutland@arm.com, al.stone@linaro.org, graeme.gregory@linaro.org, hanjun.guo@linaro.org, lorenzo.pieralisi@arm.com, sudeep.holla@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org References: <20180709234229.20181-1-takahiro.akashi@linaro.org> <20180709234229.20181-3-takahiro.akashi@linaro.org> From: James Morse Message-ID: <93c42065-bece-a4c7-ed99-5e98f91315a6@arm.com> Date: Tue, 10 Jul 2018 18:57:31 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180709234229.20181-3-takahiro.akashi@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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 think this is harmless as we end up passing NULL to early_memunmap() which WARN()s and returns as its outside the fixmap range. Its just more noise on systems with a corrupt efi system table. Acked-by: James Morse Thanks, James