From patchwork Mon May 10 09:50:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claire Chang X-Patchwork-Id: 1476282 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=OeemdSgP; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4FdxFY47Z9z9sXL for ; Mon, 10 May 2021 19:53:21 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231317AbhEJJyE (ORCPT ); Mon, 10 May 2021 05:54:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231402AbhEJJxz (ORCPT ); Mon, 10 May 2021 05:53:55 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BA58C06134C for ; Mon, 10 May 2021 02:52:41 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id m124so12872475pgm.13 for ; Mon, 10 May 2021 02:52:41 -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=TI//+rWs2AonD6qoX7ur8OGwRk/rsyDr2ocu0NzNq5I=; b=OeemdSgPmia6P5EsXKkEzN0OL4fVLwcXTd/CieenRMdBKHxFqUP4Df4joJbySWSSMc NQa62kYUP6NBQhMfe69O4Y1TVNyiYjME1kHrojL7NiW2Og6QvxSOkeGdpSahkdmKkkLI olHy6atIMBhauJm3Bf+RxBbMLkFko3Ac9JTU8= 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=TI//+rWs2AonD6qoX7ur8OGwRk/rsyDr2ocu0NzNq5I=; b=hS5cnWg/RNNKNNK6H2fqIKbWoq7mywVV+g03sbIiC7keJg8SpzrlUFoncav3alQpLR ld2SiVL8a3rb6qIXVM0HlmZ99YbZB2HEzNQVroay3L/VIg+4R7Y9Bi8BPE1YFq8g++F3 NE66G98LY/Vit2hJ371JhgxO4DRjZwiwFMg8Kgj5HnUuM2qoIPTdtuzD9xzNmKnR4XoE 3GBMP134SX71EojGxyOf/l5SD+z+VWIwbJYiDDfzW0r2jQxv8S03vZVElUxSYbJmaJ4H mMe2qlnldTjU0WFtVxGotQuVPgZzCltAZJsvuHFLJjMa7ksDPZ2qYA7IOxBgG7MSUJTA p2Xg== X-Gm-Message-State: AOAM531EXcih0iO1cbpJzoul9YeCy4koFYJB5H8XImmvspVdSHKkDX+c yhzomVeXxpQB/8WQmFY/AGmZmg== X-Google-Smtp-Source: ABdhPJx3NolYg0tYgQE7hrG22fSVZg4paXFqQrFAkVZpowUqVebMyfoHJdLoW9aBQ5hSJPVDYKavFA== X-Received: by 2002:a63:5160:: with SMTP id r32mr23960989pgl.83.1620640360984; Mon, 10 May 2021 02:52:40 -0700 (PDT) Received: from localhost ([2401:fa00:95:205:a524:abe8:94e3:5601]) by smtp.gmail.com with UTF8SMTPSA id q7sm9111446pfq.172.2021.05.10.02.52.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 10 May 2021 02:52:40 -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, nouveau@lists.freedesktop.org, rodrigo.vivi@intel.com, thomas.hellstrom@linux.intel.com Subject: [PATCH v6 14/15] dt-bindings: of: Add restricted DMA pool Date: Mon, 10 May 2021 17:50:25 +0800 Message-Id: <20210510095026.3477496-15-tientzu@chromium.org> X-Mailer: git-send-email 2.31.1.607.g51e8a6a459-goog In-Reply-To: <20210510095026.3477496-1-tientzu@chromium.org> References: <20210510095026.3477496-1-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 | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index e8d3096d922c..284aea659015 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 @@ -120,6 +137,11 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB). compatible = "acme,multimedia-memory"; reg = <0x77000000 0x4000000>; }; + + restricted_dma_mem_reserved: restricted_dma_mem_reserved { + compatible = "restricted-dma-pool"; + reg = <0x50000000 0x400000>; + }; }; /* ... */ @@ -138,4 +160,9 @@ one for multimedia processing (named multimedia-memory@77000000, 64MiB). memory-region = <&multimedia_reserved>; /* ... */ }; + + pcie_device: pcie_device@0,0 { + memory-region = <&restricted_dma_mem_reserved>; + /* ... */ + }; };