From patchwork Thu Feb 6 14:03:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 206599 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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 62C1DC2D0B1 for ; Thu, 6 Feb 2020 14:04:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35C84222C2 for ; Thu, 6 Feb 2020 14:04:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580997897; bh=1k9zgUyZTU16+bXR7Utty5v5GrnUMG0hLZQ+X8uSY8Y=; h=From:To:Cc:Subject:Date:List-ID:From; b=SiNhQwwyRegK9Htw20FM2OZ9MGGt1bMXS5OUxVIv7iHj/fr23Y0GzLkxRGzfqM/BM WgJ2K0vxMeGr2CrXb60tT2iMcyCUh8hFs54SutB6emnC9SbExQ2T/CTlEMddue/BBu jV0dyfBdFKRPT4acPcEX2NodANXloW4PJ9HJJqLY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728023AbgBFOE4 (ORCPT ); Thu, 6 Feb 2020 09:04:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:49828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726765AbgBFOE4 (ORCPT ); Thu, 6 Feb 2020 09:04:56 -0500 Received: from e123331-lin.cambridge.arm.com (fw-tnat-cam2.arm.com [217.140.106.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F124621775; Thu, 6 Feb 2020 14:04:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580997895; bh=1k9zgUyZTU16+bXR7Utty5v5GrnUMG0hLZQ+X8uSY8Y=; h=From:To:Cc:Subject:Date:From; b=pbb1jolDpUgcKiuohwjrcr6bfOirRy3U7Y7AzZ6aCdIJiT1GjWUM23U9/cv7JW+9G 4DsC9LYFOlBktgCYUcC28rgFYIeCnjM+JZWEiXH/a8wT0ru+TPHeE715LkQ8ZOqt3x teYp+ATKE8cwsO6H+UWr0lWK9YSj6AQv5lIH62Q0= From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , lersek@redhat.com, leif@nuviainc.com, pjones@redhat.com, mjg59@google.com, agraf@csgraf.de, ilias.apalodimas@linaro.org, xypron.glpk@gmx.de, daniel.kiper@oracle.com Subject: [PATCH 0/2] arch-agnostic initrd loading method for EFI systems Date: Thu, 6 Feb 2020 14:03:50 +0000 Message-Id: <20200206140352.6300-1-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org This series introduces an arch agnostic way of loading the initrd into memory from the EFI stub. This addresses a number of shortcomings that affect the current implementations that exist across architectures: - The initrd= command line option can only load files that reside on the same file system that the kernel itself was loaded from, which requires the bootloader or firmware to expose that file system via the appropriate EFI protocol, which is not always feasible. From the kernel side, this protocol is problematic since it is incompatible with mixed mode on x86 (this is due to the fact that some of its methods have prototypes that are difficult to marshall) - The approach that is ordinarily taken by GRUB is to load the initrd into memory, and pass it to the kernel proper via the bootparams structure or via the device tree. This requires the boot loader to have an understanding of those structures, which are not always set in stone, and of the policies around where the initrd may be loaded into memory. In the ARM case, it requires GRUB to modify the hardware description provided by the firmware, given that the initrd base and offset in memory are passed via the same data structure. It also creates a time window where the initrd data sits in memory, and can potentially be corrupted before the kernel is booted. Considering that we will soon have new users of these interfaces (EFI for kvmtool on ARM, RISC-V in u-boot, etc), it makes sense to add a generic interface now, before having another wave of bespoke arch specific code coming in. Another aspect to take into account is that support for UEFI secure boot and measured boot is being taken into the upstream, and being able to rely on the PE entry point for booting any architecture makes the GRUB vs shim story much cleaner, as we should be able to rely on LoadImage and StartImage on all architectures, while retaining the ability to load initrds from anywhere. Note that these patches depend on a fair amount of cleanup work that I am targetting for v5.7. Branch can be found at: https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=efistub-unification2 An implementation for ArmVirtQemu (OVMF for ARM aka AAVMF) can be found at https://github.com/ardbiesheuvel/edk2/commits/linux-efi-generic. The change is for ARM only, but the exact same code could be used on x86. Cc: lersek@redhat.com Cc: leif@nuviainc.com Cc: pjones@redhat.com Cc: mjg59@google.com Cc: agraf@csgraf.de Cc: ilias.apalodimas@linaro.org Cc: xypron.glpk@gmx.de Cc: daniel.kiper@oracle.com Ard Biesheuvel (2): efi/libstub: add support for loading the initrd from a device path efi/libstub: take noinitrd cmdline argument into account for devpath initrd drivers/firmware/efi/libstub/arm-stub.c | 21 ++++-- .../firmware/efi/libstub/efi-stub-helper.c | 74 +++++++++++++++++++ drivers/firmware/efi/libstub/efistub.h | 13 ++++ drivers/firmware/efi/libstub/x86-stub.c | 51 ++++++++++--- include/linux/efi.h | 1 + 5 files changed, 146 insertions(+), 14 deletions(-)