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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 DCC7DC3279B for ; Tue, 10 Jul 2018 18:39:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A05C0208EB for ; Tue, 10 Jul 2018 18:39:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="VbEO0wA4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A05C0208EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org 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 S1732906AbeGJSjd (ORCPT ); Tue, 10 Jul 2018 14:39:33 -0400 Received: from mail-it0-f65.google.com ([209.85.214.65]:36715 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732557AbeGJSjc (ORCPT ); Tue, 10 Jul 2018 14:39:32 -0400 Received: by mail-it0-f65.google.com with SMTP id j185-v6so81222ite.1 for ; Tue, 10 Jul 2018 11:39:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=b/qh4MmnxtcchGDhc6TQCa9qodaj+wt1P6Lw841CQsE=; b=VbEO0wA4MRaXUdYoFuQOdzSE6m4MyPMKxKp7oOLgz3MFnAatXJA+Zu0C3q7q0Z/6NI juw6JriPwlFo8DwKJSzTD9ZWe4lvJT9LkB5d9SwrdB39G9GV8gN+BlJYdFKb3Af0sS8Q +wK3rbTZu7XOVMcktCc1MCU7G4SEmFFr2tVdY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=b/qh4MmnxtcchGDhc6TQCa9qodaj+wt1P6Lw841CQsE=; b=PPEApLLmz20ynJ3Pqj/bqixvg9ClzFpUXqPdRE1wZ+FqDch/KMnCGWb6aq8qHRFyxh 6x5aavmWLpZv5B+Gyvjxk34ToPfAKpHQ6q8VaMgxKwQ3PO4cz8W/82XxbeS16MoGthdN dzL648btTuZWlrHs1epPzrT9Htxou7leNwqBv2/ff6BFKVJtxMGRF7RNl2IjCFGGDWG6 v1uf0ITQ8hMKdsms0BH3GVQXOgy1I0gVfOAfB7nHwAkOXRB2mLXyM+bFd6Lu/btx64lD vuVRO9zGqV3l95dVXG7ngyc/RU6hD/ap+VfdZv5cnEHASqu5Sjapx8NpOG565zaUMSt4 1imQ== X-Gm-Message-State: APt69E22Jb5HJ7T/eOKsXQGabT07aSHE9yOyRoPMatrRAa2CMBmMNL0n fFAFrSMPSNQ72W9FEqcnwE9h8dxwNfH4kkYmliwGPA== X-Google-Smtp-Source: AAOMgpc4/PFXdqst0QdZGWowAXs9bbGpKnd1AYmF1To5SAZzkLovUWiRXPKKKmCY2mB09wP0W6yqShmBmLPKq5zpHEw= X-Received: by 2002:a24:64d6:: with SMTP id t205-v6mr20544353itc.138.1531247957366; Tue, 10 Jul 2018 11:39:17 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a6b:bbc7:0:0:0:0:0 with HTTP; Tue, 10 Jul 2018 11:39:16 -0700 (PDT) In-Reply-To: <93c42065-bece-a4c7-ed99-5e98f91315a6@arm.com> References: <20180709234229.20181-1-takahiro.akashi@linaro.org> <20180709234229.20181-3-takahiro.akashi@linaro.org> <93c42065-bece-a4c7-ed99-5e98f91315a6@arm.com> From: Ard Biesheuvel Date: Tue, 10 Jul 2018 20:39:16 +0200 Message-ID: Subject: Re: [PATCH v3.1 2/4] efi/arm: preserve early mapping of UEFI memory map longer for BGRT To: James Morse Cc: AKASHI Takahiro , Catalin Marinas , Will Deacon , "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 Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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