From patchwork Wed Jul 29 11:30:39 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 51654 Return-Path: X-Original-To: linaro@patches.linaro.org Delivered-To: linaro@patches.linaro.org Received: from mail-la0-f71.google.com (mail-la0-f71.google.com [209.85.215.71]) by patches.linaro.org (Postfix) with ESMTPS id 6D7CE214B7 for ; Wed, 29 Jul 2015 11:32:34 +0000 (UTC) Received: by lafd3 with SMTP id d3sf2767703laf.1 for ; Wed, 29 Jul 2015 04:32:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:delivered-to:from:to:subject:date:message-id :precedence:list-id:list-unsubscribe:list-archive:list-post :list-help:list-subscribe:cc:mime-version:content-type :content-transfer-encoding:sender:errors-to:x-original-sender :x-original-authentication-results:mailing-list; bh=2yZ+sJAUnxkC9NOw2ZZIH8EcgfI7/6c8m5rtaAxg2Xg=; b=JlXZ1und2vDuaSA5JTG1gKUVr7pCaEHkr7apLKBjGej90SLQ+JR4slDgFMAlpMcKHb t7Mjb5IPNRG2hhZ1PbrYt416cxrAhEaEOUj133wFmUNA6Di/SviDvaAlk3me+97lUthk j7T+yZWbdoTG9VxmchT6QtTJ5bb8j4zI/41BBs6P6dJnPZLXu5BrePOnk9Q5+UF88WMs R6KKVpd7ku7UdzGaGR+13QETRqo42tCu+2wjiCjL/GEouoIXM/y16ugRUOZt+35QuTfc qBhvqKsphbiB3yQhiTP/5uu8vFEr/mo1pwuSOJ27/Y80eibaxhQLNl8x4BG5j0lRdWAN 6sYg== X-Gm-Message-State: ALoCoQnbGM4NfygNIHsscHEVrZxoiCfqfIzlQsGKksU7Q3+oFSkXn4w1rqPWahXd33gm4pLnZXWq X-Received: by 10.112.148.101 with SMTP id tr5mr15947516lbb.13.1438169552970; Wed, 29 Jul 2015 04:32:32 -0700 (PDT) X-BeenThere: patchwork-forward@linaro.org Received: by 10.152.21.35 with SMTP id s3ls32227lae.29.gmail; Wed, 29 Jul 2015 04:32:32 -0700 (PDT) X-Received: by 10.112.48.68 with SMTP id j4mr37386379lbn.60.1438169552827; Wed, 29 Jul 2015 04:32:32 -0700 (PDT) Received: from mail-lb0-f181.google.com (mail-lb0-f181.google.com. [209.85.217.181]) by mx.google.com with ESMTPS id b6si21261111laa.94.2015.07.29.04.32.32 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Jul 2015 04:32:32 -0700 (PDT) Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.181 as permitted sender) client-ip=209.85.217.181; Received: by lbbst4 with SMTP id st4so4591007lbb.1 for ; Wed, 29 Jul 2015 04:32:32 -0700 (PDT) X-Received: by 10.112.166.2 with SMTP id zc2mr38138617lbb.29.1438169552710; Wed, 29 Jul 2015 04:32:32 -0700 (PDT) X-Forwarded-To: patchwork-forward@linaro.org X-Forwarded-For: patch@linaro.org patchwork-forward@linaro.org Delivered-To: patch@linaro.org Received: by 10.112.7.198 with SMTP id l6csp2696611lba; Wed, 29 Jul 2015 04:32:31 -0700 (PDT) X-Received: by 10.50.109.233 with SMTP id hv9mr725425igb.92.1438169551067; Wed, 29 Jul 2015 04:32:31 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id bm6si8962092pad.85.2015.07.29.04.32.30 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Jul 2015 04:32:31 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; 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 1ZKPZr-0003Os-DH; Wed, 29 Jul 2015 11:31:15 +0000 Received: from mail-wi0-f169.google.com ([209.85.212.169]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZKPZn-0003IK-Qo for linux-arm-kernel@lists.infradead.org; Wed, 29 Jul 2015 11:31:12 +0000 Received: by wicgb10 with SMTP id gb10so196072425wic.1 for ; Wed, 29 Jul 2015 04:30:50 -0700 (PDT) X-Received: by 10.180.79.4 with SMTP id f4mr16858016wix.83.1438169450072; Wed, 29 Jul 2015 04:30:50 -0700 (PDT) Received: from localhost.localdomain ([185.13.106.66]) by smtp.gmail.com with ESMTPSA id n6sm23896622wix.1.2015.07.29.04.30.47 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 29 Jul 2015 04:30:49 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, will.deacon@arm.com, mark.rutland@arm.com Subject: [PATCH] arm64/Documentation: clarify wording regarding memory below the Image Date: Wed, 29 Jul 2015 13:30:39 +0200 Message-Id: <1438169439-15216-1-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 1.9.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150729_043112_025431_F41EB64F X-CRM114-Status: GOOD ( 16.66 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.212.169 listed in list.dnswl.org] -0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [209.85.212.169 listed in wl.mailspike.net] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: , List-Help: , List-Subscribe: , Cc: Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: ard.biesheuvel@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.181 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 Clarify that the memory below the start of the image but inside the region covered by the linear mapping has no special significance to the kernel, and may be used by the firmware provided that it is marked as reserved. Also, fix up some whitespace errors. Signed-off-by: Ard Biesheuvel --- Documentation/arm64/booting.txt | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt index 1690350f16e7..7d9d3c2286b2 100644 --- a/Documentation/arm64/booting.txt +++ b/Documentation/arm64/booting.txt @@ -81,7 +81,7 @@ The decompressed kernel image contains a 64-byte header as follows: u64 res3 = 0; /* reserved */ u64 res4 = 0; /* reserved */ u32 magic = 0x644d5241; /* Magic number, little endian, "ARM\x64" */ - u32 res5; /* reserved (used for PE COFF offset) */ + u32 res5; /* reserved (used for PE COFF offset) */ Header notes: @@ -103,7 +103,7 @@ Header notes: - The flags field (introduced in v3.17) is a little-endian 64-bit field composed as follows: - Bit 0: Kernel endianness. 1 if BE, 0 if LE. + Bit 0: Kernel endianness. 1 if BE, 0 if LE. Bits 1-63: Reserved. - When image_size is zero, a bootloader should attempt to keep as much @@ -115,11 +115,14 @@ The Image must be placed text_offset bytes from a 2MB aligned base address near the start of usable system RAM and called there. Memory below that base address is currently unusable by Linux, and therefore it is strongly recommended that this location is the start of system RAM. +The region between the 2 MB aligned base address and the start of the +image has no special significance to the kernel, and may be used for +other purposes. At least image_size bytes from the start of the image must be free for use by the kernel. -Any memory described to the kernel (even that below the 2MB aligned base -address) which is not marked as reserved from the kernel e.g. with a +Any memory described to the kernel (even that below the start of the +image) which is not marked as reserved from the kernel (e.g., with a memreserve region in the device tree) will be considered as available to the kernel.