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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 19426C433E0 for ; Tue, 16 Mar 2021 07:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB21D64FFC for ; Tue, 16 Mar 2021 07:58:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230204AbhCPH6B (ORCPT ); Tue, 16 Mar 2021 03:58:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:52288 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233632AbhCPH5c (ORCPT ); Tue, 16 Mar 2021 03:57:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DE27665004; Tue, 16 Mar 2021 07:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615881452; bh=b7zB8HUrfryXGgt2WC1quPqyBMriofSRX3gUzUhaizo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=E473bAIY8aeE9lsMMuLBxv5uiHnCBnwbN3YE/nEUNZA7zSaglVKCB9GVLXMgn0rbL a2fsplDnFNWrrqzOuUVD+wVneflFAGy/HwvW6SiFWs4Kh7K5CvvnPHBO8FmXkOjPjZ dHAtJ/u1ubYDawVLA/7vWuzB8z0vq7EGPwBWpV6irXBCEYHsbqbSrMNJmG0X73vxHU UMViB0CYmGkPs5yCvuug5+tMC+BzZlORH9ZjbQwCBWGZmCzYAxtAIdNFPin0I2TGiV 7ZKajgB0vuEX6AezSGkv60vwPR6KZ8KK7cYIOzx9OAeAP/fWSORZwQyMuzRiZwIet3 9m8tbNd3VK+DA== Received: by mail-oo1-f49.google.com with SMTP id x187-20020a4a41c40000b02901b664cf3220so3918927ooa.10; Tue, 16 Mar 2021 00:57:31 -0700 (PDT) X-Gm-Message-State: AOAM533uWF1ackKK+AsFGj9oRBpLqAErVInoXSLzxODT+sTdCrVAhGTL mWu5VP/MttWpxEqNNoXKhvih1J4WRsJFjwyYnB8= X-Google-Smtp-Source: ABdhPJxJMUjZTiiE46HDAh0r5i4CnwL1PTkpdHki4NDKe2BYi6ERpfLDy7Bt54gUOpnkupA3qT9bYa38GtpZgHXYbk8= X-Received: by 2002:a4a:bd1a:: with SMTP id n26mr2677121oop.45.1615881450963; Tue, 16 Mar 2021 00:57:30 -0700 (PDT) MIME-Version: 1.0 References: <20210306113519.294287-1-ardb@kernel.org> <20210307110228.GP17424@dragon> <20210309032248.GR17424@dragon> <20210315031119.GY17424@dragon> <20210316075214.GA32651@dragon> In-Reply-To: <20210316075214.GA32651@dragon> From: Ard Biesheuvel Date: Tue, 16 Mar 2021 08:57:19 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] efi: stub: override RT_PROP table supported mask based on EFI variable To: Shawn Guo Cc: Heinrich Schuchardt , Atish Patra , Ilias Apalodimas , Steve McIntyre , Rob Clark , linux-efi , Jeffrey Hugo , Bjorn Andersson , Leif Lindholm , linux-arm-msm Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue, 16 Mar 2021 at 08:52, Shawn Guo wrote: > > On Mon, Mar 15, 2021 at 02:07:01PM +0100, Ard Biesheuvel wrote: > > On Mon, 15 Mar 2021 at 04:11, Shawn Guo wrote: > > > > > > On Tue, Mar 09, 2021 at 07:47:25PM +0100, Ard Biesheuvel wrote: > > > > On Tue, 9 Mar 2021 at 19:10, Rob Clark wrote: > > > > > > > ... > > > > > fwiw, the valid use-case for ACPI boot on these things is for distro > > > > > installer.. it might not be the shiny accelerated experience, but you > > > > > want to be able to get thru the installer and then install updates to > > > > > get latest kernel/dtb/etc > > > > > > > > > > it is a small use-case, but kinda an important step ;-) > > > > > > > > > > > > > That is a fair point. However, as I understand it, we need this to work around > > > > - the need to pass efi=novamap > > > > - broken poweroff on Flex5g > > > > > > One more: broken EFI variable runtime services on all Snapdragon laptops > > > > > > It's been another pain of running debian-installer (d-i) on these > > > laptops, where EFI NV variables are just stored on UFS disk. So after > > > Linux takes over the control of UFS, EFI NV variable runtime services > > > then become out of service. Currently, we have to apply a hack [1] on > > > d-i grub-installer to get around the issue, and it's been the only > > > remaining out-of-tree patch we have to carry for d-i. With this nice > > > `OverrideSupported` support, we will be able to drop that hack > > > completely. > > > > > > > > > > > So an installer either needs to set the EFI variable, or pass > > > > efi=novamap on the first boot. Note that there are no arm64 EFI > > > > systems known where efi=novamap causes problems. In fact, I would > > > > prefer to stop using SetVirtualAddressMap() altogether, as it does not > > > > provide any benefit whatsoever. So perhaps we should make efi=novamap > > > > the default and be done with it. > > > > > > > > Broken poweroff is hardly a showstopper for an installer, given that > > > > we cannot even install GRUB correctly. > > > > > > > > In summary, I am more than happy to collaborate constructively on this > > > > (which is why I wrote the patch), but I don't think we're at a point > > > > yet where this is the only thing standing in our way when it comes to > > > > a smooth out-of-the-box Linux installation experience. > > > > > > There might be more to be done for getting a smooth Linux installation > > > experience. But IMHO, this `OverrideSupported` thing is definitely > > > a big step to that. > > > > > > > So the problem here seems to be that grub-install (or efibootmgr) > > tolerates efivarfs being absent entirely, but bails out if it exists > > but gives an error when trying to access it, right? > > Yes, with EFI variables runtime service marked as unsupported, > efibootmgr will just exit on efi_variables_supported() check [1] in > a way that its parent process, i.e. grub-install, doesn't take as an > error. But otherwise, efibootmgr will go much further and exit with > a real error when trying to access efivars. > OK, so I suggest we fix efibootmgr, by extending the efi_variables_supported() check to perform a GetVariable() call on an arbitrary variable (e.g., BootOrder), and treat EFI_UNSUPPORTED as a special case that means that carrying on is pointless. (but someone please confirm that the snapdragon efi firmware does return EFI_UNSUPPORTED and not some other return value when calling GetVariable() from under the OS)