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 A2394C6778C for ; Thu, 5 Jul 2018 16:47:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58933240FB for ; Thu, 5 Jul 2018 16:47:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58933240FB 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 S1753607AbeGEQrq (ORCPT ); Thu, 5 Jul 2018 12:47:46 -0400 Received: from foss.arm.com ([217.140.101.70]:53864 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753325AbeGEQrp (ORCPT ); Thu, 5 Jul 2018 12:47:45 -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 D90C87A9; Thu, 5 Jul 2018 09:47:44 -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 A8E4C3F5BA; Thu, 5 Jul 2018 09:47:44 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id D79B61AE3105; Thu, 5 Jul 2018 17:48:24 +0100 (BST) Date: Thu, 5 Jul 2018 17:48:24 +0100 From: Will Deacon To: James Morse Cc: AKASHI Takahiro , Ard Biesheuvel , Catalin Marinas , Andrew Morton , "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 v2 3/4] efi/arm: map UEFI memory map earlier on boot Message-ID: <20180705164824.GA7445@arm.com> References: <20180619064424.6642-1-takahiro.akashi@linaro.org> <20180619064424.6642-4-takahiro.akashi@linaro.org> <20180704170655.GD8370@arm.com> <20180705094313.GL28220@linaro.org> 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 Thu, Jul 05, 2018 at 12:02:15PM +0100, James Morse wrote: > On 05/07/18 10:43, AKASHI Takahiro wrote: > > On Wed, Jul 04, 2018 at 08:49:32PM +0200, Ard Biesheuvel wrote: > >> On 4 July 2018 at 19:06, Will Deacon wrote: > >>> On Tue, Jun 19, 2018 at 03:44:23PM +0900, AKASHI Takahiro wrote: > >>>> Since arm_enter_runtime_services() was modified to always create a virtual > >>>> mapping of UEFI memory map in the previous patch, it is now renamed to > >>>> efi_enter_virtual_mode() and called earlier before acpi_load_tables() > >>>> in acpi_early_init(). > >>>> > >>>> This will allow us to use UEFI memory map in acpi_os_ioremap() to create > >>>> mappings of ACPI tables using memory attributes described in UEFI memory > >>>> map. > > >>> Hmm, this is ugly as hell. Is there nothing else we can piggy-back off? > >>> It's also fairly jarring that, on x86, efi_enter_virtual_mode() is called > >>> a few lines later, *after* acpi_early_init() has been called. > > >> Currently, there is a gap where we have already torn down the early > >> mapping and haven't created the definitive mapping of the UEFI memory > >> map. There are other reasons why this is an issue, and I recently > >> proposed [0] myself to address one of them > > >> Akashi-san, could you please confirm whether the patch below would be > >> sufficient for you? Apologies for going back and forth on this, but I > >> agree with Will that we should try to avoid warts like the one above > >> in generic code. > >> > >> [0] https://marc.info/?l=linux-efi&m=152930773507524&w=2 > > > > I think that this patch will also work. > > Please drop my patch#2 and #3 if you want to pick up my patchset, Will. > > Patch 2 is what changes arm_enable_runtime_services() to map the efi memory map > before bailing out due to efi=noruntime. > > Without it, 'efi=noruntime' means no-acpi-tables. So it sounds like we want patch 2. Akashi, given that this series is only four patches, please can you send out a v3 with the stuff that should be reviewed and merged? Otherwise, there's a real risk we end up with breakage that goes unnoticed initially. Thanks, Will