From patchwork Tue Jun 15 13:27:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claire Chang X-Patchwork-Id: 1492188 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@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=devicetree-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=WOU8IVzg; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4G48L26pNyz9t54 for ; Tue, 15 Jun 2021 23:29:14 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231495AbhFONbR (ORCPT ); Tue, 15 Jun 2021 09:31:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231519AbhFONbE (ORCPT ); Tue, 15 Jun 2021 09:31:04 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E50BC06121D for ; Tue, 15 Jun 2021 06:29:00 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id h16so11787393pjv.2 for ; Tue, 15 Jun 2021 06:29:00 -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=GymVnULBeJ03m5EPo7c7VEX7DSqoBwMT6L2fMWoeeEc=; b=WOU8IVzg+iYvk6N5b67KD5CKh5Wgn355zu5PCMe6mPVyyUQjES9RmEtfXkhuQMaXmA hHjDKIazD9xu9BtywBAgsYVdsMG3DqbHBxwCuAdZqvctaQSD9keTHyqXNfZ2Km99muyW YJc+kW7TLNcpm9kWU0l/wPI+emgUC6NSvuBJc= 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=GymVnULBeJ03m5EPo7c7VEX7DSqoBwMT6L2fMWoeeEc=; b=Ub5fXiIStaOV2X325zIVw7Bn9WCD+h6nwSKrBnPcNIRDQLUWDcSDukUVk2HfJP62cU +8gMIXyCG8vmFdhksQGeYboMpQhdfCjEs/Vs6HbqkMyE8QzXJyya/1hJ7mgM9ywr50RI RSs/9EKS6JdrNBHy7iF5oCKXr1uacvdk2cfFj5ycdUGg2Qd6702eJGe0AgF7p2jkORSj Ea9VV/T7fhGtSdthFOkGgU3FHiGX1cKTsfsk1SJrZdBCr6SVIAnJ/CKtHYCRVpUignqV PIRZoiSa/g/630hiaYThYgB8Mp0aeLgVbj91FGq4ZzxpR97Gus9FVU3DYQ75+Al44z17 /FLQ== X-Gm-Message-State: AOAM530ekjh08CM6D+itfeccbqTOAVCUt1OS2DfEq5lwKU+lfRKFBohZ xugsGnjPclTQj8kyV19Q+k2IwA== X-Google-Smtp-Source: ABdhPJwFBj2pKeWU+1SEbsBI+u3Jw3SyjbFfiN066dPovK3+ci3+q1oZRASaC88XjKL/ShDd5jcc2w== X-Received: by 2002:a17:90a:a116:: with SMTP id s22mr24962655pjp.218.1623763739540; Tue, 15 Jun 2021 06:28:59 -0700 (PDT) Received: from localhost ([2401:fa00:95:205:1846:5274:e444:139e]) by smtp.gmail.com with UTF8SMTPSA id y205sm15379907pfb.53.2021.06.15.06.28.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Jun 2021 06:28:59 -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 Subject: [PATCH v10 11/12] dt-bindings: of: Add restricted DMA pool Date: Tue, 15 Jun 2021 21:27:10 +0800 Message-Id: <20210615132711.553451-12-tientzu@chromium.org> X-Mailer: git-send-email 2.32.0.272.g935e593368-goog In-Reply-To: <20210615132711.553451-1-tientzu@chromium.org> References: <20210615132711.553451-1-tientzu@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@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 --- .../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..46804f24df05 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_mem_reserved>; + /* ... */ + }; };