From patchwork Fri Apr 25 16:09:11 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leif Lindholm X-Patchwork-Id: 4064361 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 361629F1F4 for ; Fri, 25 Apr 2014 16:13:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5A6C82021A for ; Fri, 25 Apr 2014 16:13:41 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 49FF92034A for ; Fri, 25 Apr 2014 16:13:39 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wdiin-000194-Id; Fri, 25 Apr 2014 16:11:29 +0000 Received: from mail-wi0-f175.google.com ([209.85.212.175]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wdii9-0000Mc-Hk for linux-arm-kernel@lists.infradead.org; Fri, 25 Apr 2014 16:10:50 +0000 Received: by mail-wi0-f175.google.com with SMTP id cc10so2924436wib.8 for ; Fri, 25 Apr 2014 09:10:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=xsLolm7jmL2AB+iT2VdZxAISKI+0P3umcOx1wo/C6Zk=; b=lE/XJ0H8HzQo59aLIjyqOQrwUqc3VltM+oFLHTmY8GMc5Hl3inNksmau2zEniu3J7H LLoG4eGqFI+iRDx824K6rO05L3q+ByOljOfr2WYS5P2mWuYL3zPBG5ZHvku3RQok11xB dHigd5XmBymkNvj4jsaE5iBe0f2TvyLl/+0ubpzTzo8pUhN5blS548pYa+x7iGeSu45f zQS06aa9mPL3OHxFwFJe5bb3n8rcKnO2hz+hpwIFWAT4LRermtIDAhNg3dRYLYm2py4t cPn2FNSiwamHlpbuPvLV99nytKcbKXBEYTjL1IX5HIpnCAlYXqmniqUbWme4BGlChUu5 ghsQ== X-Gm-Message-State: ALoCoQmsprbvZF3RXw41dovg1JZrUyTuo3v+AYId6IGgMZ95qTM60ST7+canFKbTEC9pdrTqVZEE X-Received: by 10.180.106.132 with SMTP id gu4mr4428282wib.26.1398442227407; Fri, 25 Apr 2014 09:10:27 -0700 (PDT) Received: from mohikan.mushroom.smurfnet.nu (cpc4-cmbg17-2-0-cust71.5-4.cable.virginm.net. [86.14.224.72]) by mx.google.com with ESMTPSA id uy4sm11813046wjc.8.2014.04.25.09.10.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Apr 2014 09:10:26 -0700 (PDT) From: Leif Lindholm To: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 07/10] doc: arm: add UEFI support documentation Date: Fri, 25 Apr 2014 17:09:11 +0100 Message-Id: <1398442154-19974-8-git-send-email-leif.lindholm@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1398442154-19974-1-git-send-email-leif.lindholm@linaro.org> References: <1398442154-19974-1-git-send-email-leif.lindholm@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140425_091049_752704_3607D382 X-CRM114-Status: GOOD ( 17.09 ) X-Spam-Score: -0.7 (/) Cc: mark.rutland@arm.com, matt.fleming@intel.com, ard.biesheuvel@linaro.org, catalin.marinas@arm.com, linux-doc@vger.kernel.org, roy.franz@linaro.org, msalter@redhat.com, grant.likely@linaro.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch provides documentation of the [U]EFI runtime service and configuration features for the arm architecture. Signed-off-by: Leif Lindholm Acked-by: Grant Likely --- Documentation/arm/00-INDEX | 2 ++ Documentation/arm/uefi.txt | 64 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) create mode 100644 Documentation/arm/uefi.txt diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX index a94090c..3b08bc2 100644 --- a/Documentation/arm/00-INDEX +++ b/Documentation/arm/00-INDEX @@ -46,5 +46,7 @@ swp_emulation - SWP/SWPB emulation handler/logging description tcm.txt - ARM Tightly Coupled Memory +uefi.txt + - [U]EFI configuration and runtime services documentation vlocks.txt - Voting locks, low-level mechanism relying on memory system atomic writes. diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt new file mode 100644 index 0000000..d60030a --- /dev/null +++ b/Documentation/arm/uefi.txt @@ -0,0 +1,64 @@ +UEFI, the Unified Extensible Firmware Interface, is a specification +governing the behaviours of compatible firmware interfaces. It is +maintained by the UEFI Forum - http://www.uefi.org/. + +UEFI is an evolution of its predecessor 'EFI', so the terms EFI and +UEFI are used somewhat interchangeably in this document and associated +source code. As a rule, anything new uses 'UEFI', whereas 'EFI' refers +to legacy code or specifications. + +UEFI support in Linux +===================== +Booting on a platform with firmware compliant with the UEFI specification +makes it possible for the kernel to support additional features: +- UEFI Runtime Services +- Retrieving various configuration information through the standardised + interface of UEFI configuration tables. (ACPI, SMBIOS, ...) + +For actually enabling [U]EFI support, enable: +- CONFIG_EFI=y +- CONFIG_EFI_VARS=y or m + +The implementation depends on receiving information about the UEFI environment +in a Flattened Device Tree (FDT) - so is only available with CONFIG_OF. + +UEFI stub +========= +The "stub" is a feature that extends the Image/zImage into a valid UEFI +PE/COFF executable, including a loader application that makes it possible to +load the kernel directly from the UEFI shell, boot menu, or one of the +lightweight bootloaders like Gummiboot or rEFInd. + +The kernel image built with stub support remains a valid kernel image for +booting in non-UEFI environments. + +UEFI kernel support on ARM +========================== +UEFI kernel support on the ARM architectures (arm and arm64) is only available +when boot is performed through the stub. + +When booting in UEFI mode, the stub deletes any memory nodes from a provided DT. +Instead, the kernel reads the UEFI memory map. + +The stub populates the FDT /chosen node with (and the kernel scans for) the +following parameters: +________________________________________________________________________________ +Name | Size | Description +================================================================================ +linux,uefi-system-table | 64-bit | Physical address of the UEFI System Table. +-------------------------------------------------------------------------------- +linux,uefi-mmap-start | 64-bit | Physical address of the UEFI memory map, + | | populated by the UEFI GetMemoryMap() call. +-------------------------------------------------------------------------------- +linux,uefi-mmap-size | 32-bit | Size in bytes of the UEFI memory map + | | pointed to in previous entry. +-------------------------------------------------------------------------------- +linux,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI + | | memory map. +-------------------------------------------------------------------------------- +linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format. +-------------------------------------------------------------------------------- +linux,uefi-stub-kern-ver | string | Copy of linux_banner from build. +-------------------------------------------------------------------------------- + +For verbose debug messages, specify 'uefi_debug' on the kernel command line.