From patchwork Sat Jun 19 03:40:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claire Chang X-Patchwork-Id: 1494566 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=Wu0eLHFq; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4G6M7n4XYvz9s5R for ; Sat, 19 Jun 2021 13:43:01 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235770AbhFSDpJ (ORCPT ); Fri, 18 Jun 2021 23:45:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235810AbhFSDon (ORCPT ); Fri, 18 Jun 2021 23:44:43 -0400 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F1ADC0617A8 for ; Fri, 18 Jun 2021 20:42:33 -0700 (PDT) Received: by mail-pf1-x433.google.com with SMTP id z26so9214008pfj.5 for ; Fri, 18 Jun 2021 20:42:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=YPdZA059qJtBhHo92L+QtxB+I/HHPOi+M+A9tEqXqKY=; b=Wu0eLHFq0Y/87UVuH2wG2UQKehneEtjyPBVQdTP1lnkewLoZWvPjWvbDIzh+Arzpty 6/gTzGLkVnr6kmY9LH3UOa/5MBfVIDw2V2Pk6DizW41XnS2UTJ+egFCFXcGunjOko5uu NFfdBa59v19TyyGjeObnddQmZaP9dKr5Tb8k0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=YPdZA059qJtBhHo92L+QtxB+I/HHPOi+M+A9tEqXqKY=; b=orgLjhr1cXWhotNksfO/XgdWqgLDg37JY443d+kC1clYDwyG3Y/bg2SgEjXMZOtHLJ dRZ4lYNUG/6uQHdJNVrMsfMDk7/qgqDK5Ccn6yFL/Oyf2UqAC0M2PGbqW7ysz2J3UUAy EG0ipo2Ml6pe8SUNtSa4ykszWJ/q+flXQvj3L5zRHBaMh3TL1IeOLsrQOfLFQe40prYB YQ9P9hXDmCjPYlINC0cXmnC6PeJab7ADTdR46KxEcGIMQnQYKWRWUU8kvvZ1IyPyRzXG 3IOosrfAS9j6VCyNm3NuZYWQWENBknssHomKqngZDvNByjbGjqYYVWlhc+tbuBSG+Qdy kkQQ== X-Gm-Message-State: AOAM532/sH4vrDo+lnEHOaNRUQ1GNRtkhfYicnBrS6k181NnLH/bzbl0 FKw5b8exwMUP3hjIkpb0QsmyGQ== X-Google-Smtp-Source: ABdhPJzLaZpsZm1niTfUb8nxR32Zg+/27KFI+rEZFvk6OtIgjDsZGMpMmjJEaTHEl6JDmRuEDbffng== X-Received: by 2002:a63:6644:: with SMTP id a65mr12953547pgc.431.1624074152888; Fri, 18 Jun 2021 20:42:32 -0700 (PDT) Received: from localhost ([2401:fa00:95:205:4a46:e208:29e8:e076]) by smtp.gmail.com with UTF8SMTPSA id h8sm10337503pgr.43.2021.06.18.20.42.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Jun 2021 20:42:32 -0700 (PDT) From: Claire Chang To: Rob Herring , mpe@ellerman.id.au, Joerg Roedel , Will Deacon , Frank Rowand , Konrad Rzeszutek Wilk , boris.ostrovsky@oracle.com, jgross@suse.com, Christoph Hellwig , Marek Szyprowski Cc: benh@kernel.crashing.org, paulus@samba.org, "list@263.net:IOMMU DRIVERS" , sstabellini@kernel.org, Robin Murphy , grant.likely@arm.com, xypron.glpk@gmx.de, Thierry Reding , mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org, Greg KH , Saravana Kannan , "Rafael J . Wysocki" , heikki.krogerus@linux.intel.com, Andy Shevchenko , Randy Dunlap , Dan Williams , Bartosz Golaszewski , linux-devicetree , lkml , linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xenproject.org, Nicolas Boichat , Jim Quinlan , tfiga@chromium.org, bskeggs@redhat.com, bhelgaas@google.com, chris@chris-wilson.co.uk, tientzu@chromium.org, daniel@ffwll.ch, airlied@linux.ie, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com, jxgao@google.com, joonas.lahtinen@linux.intel.com, linux-pci@vger.kernel.org, maarten.lankhorst@linux.intel.com, matthew.auld@intel.com, rodrigo.vivi@intel.com, thomas.hellstrom@linux.intel.com, thomas.lendacky@amd.com Subject: [PATCH v14 11/12] dt-bindings: of: Add restricted DMA pool Date: Sat, 19 Jun 2021 11:40:42 +0800 Message-Id: <20210619034043.199220-12-tientzu@chromium.org> X-Mailer: git-send-email 2.32.0.288.g62a8d224e6-goog In-Reply-To: <20210619034043.199220-1-tientzu@chromium.org> References: <20210619034043.199220-1-tientzu@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Introduce the new compatible string, restricted-dma-pool, for restricted DMA. One can specify the address and length of the restricted DMA memory region by restricted-dma-pool in the reserved-memory node. Signed-off-by: Claire Chang Tested-by: Stefano Stabellini Tested-by: Will Deacon --- .../reserved-memory/reserved-memory.txt | 36 +++++++++++++++++-- 1 file changed, 33 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index e8d3096d922c..39b5f4c5a511 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -51,6 +51,23 @@ compatible (optional) - standard definition used as a shared pool of DMA buffers for a set of devices. It can be used by an operating system to instantiate the necessary pool management subsystem if necessary. + - restricted-dma-pool: This indicates a region of memory meant to be + used as a pool of restricted DMA buffers for a set of devices. The + memory region would be the only region accessible to those devices. + When using this, the no-map and reusable properties must not be set, + so the operating system can create a virtual mapping that will be used + for synchronization. The main purpose for restricted DMA is to + mitigate the lack of DMA access control on systems without an IOMMU, + which could result in the DMA accessing the system memory at + unexpected times and/or unexpected addresses, possibly leading to data + leakage or corruption. The feature on its own provides a basic level + of protection against the DMA overwriting buffer contents at + unexpected times. However, to protect against general data leakage and + system memory corruption, the system needs to provide way to lock down + the memory access, e.g., MPU. Note that since coherent allocation + needs remapping, one must set up another device coherent pool by + shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic + coherent allocation. - vendor specific string in the form ,[-] no-map (optional) - empty property - Indicates the operating system must not create a virtual mapping @@ -85,10 +102,11 @@ memory-region-names (optional) - a list of names, one for each corresponding Example ------- -This example defines 3 contiguous regions are defined for Linux kernel: +This example defines 4 contiguous regions for Linux kernel: one default of all device drivers (named linux,cma@72000000 and 64MiB in size), -one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and -one for multimedia processing (named multimedia-memory@77000000, 64MiB). +one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), +one for multimedia processing (named multimedia-memory@77000000, 64MiB), and +one for restricted dma pool (named restricted_dma_reserved@0x50000000, 64MiB). / { #address-cells = <1>; @@ -120,6 +138,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB). compatible = "acme,multimedia-memory"; reg = <0x77000000 0x4000000>; }; + + restricted_dma_reserved: restricted_dma_reserved { + compatible = "restricted-dma-pool"; + reg = <0x50000000 0x4000000>; + }; }; /* ... */ @@ -138,4 +161,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB). memory-region = <&multimedia_reserved>; /* ... */ }; + + pcie_device: pcie_device@0,0 { + reg = <0x83010000 0x0 0x00000000 0x0 0x00100000 + 0x83010000 0x0 0x00100000 0x0 0x00100000>; + memory-region = <&restricted_dma_reserved>; + /* ... */ + }; };