From patchwork Tue Feb 9 06:21:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claire Chang X-Patchwork-Id: 1438121 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=I1pOI9d2; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DZXtS1f6gz9sS8 for ; Tue, 9 Feb 2021 17:24:48 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230080AbhBIGY1 (ORCPT ); Tue, 9 Feb 2021 01:24:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230171AbhBIGXs (ORCPT ); Tue, 9 Feb 2021 01:23:48 -0500 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1A47C061794 for ; Mon, 8 Feb 2021 22:23:17 -0800 (PST) Received: by mail-pg1-x52b.google.com with SMTP id m2so5091116pgq.5 for ; Mon, 08 Feb 2021 22:23:17 -0800 (PST) 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=eRi8Yzf5Y8qG5991xxXPsSC5LTyacs0FIIEghf5qlqE=; b=I1pOI9d2uMAOj25XXD6wAuAIs02PiqHn3vYbrTGQfRLUalLAaaWHj4AP66p1gZRw6c B3Fs+yS4m4TscPVDCU+jECnoKxyq5OcojOQ3UlsKgJX/2bKZw0g3cUyt8Lb9tyEzB+I7 d4RC5Ezyz3o4oj5hhy8N+DKnKQ48mOYCkG1WM= 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=eRi8Yzf5Y8qG5991xxXPsSC5LTyacs0FIIEghf5qlqE=; b=KtCmPBdNNOdD2LziNWv8hK3/NqhnqC3Qxh+dzbtzN7Tzi6laV7akCaR4YcTSjmG2Gl fJKNtYK+Z7WrdwvtXvk2di6l66txhuVJS6MJ9mDu36tyqSxrqQV6AH7M6Y845GoFfaIF TbNoEZBY+nQSNtU8otgpKrejEISF7NGHIbY/mmFeHp6Ze7P4FIoK+w6fjOEZ0vkZnIN6 s5LnxTlr5bYM1U3mG+GpIMQrH+iPGTO8WlPrKQPrjC3k7GEd/Z13i6Mf2HUdd31nVQjd 2UCBBXvswbQr9l8viy5odgrPzJLIbO8odH9P6fkbtPNdpcuUxa2/lT636M5l0yts9mEB vFgg== X-Gm-Message-State: AOAM530pAhrj7fa9wfqOfIl9DxNMgpKMAc3d/KEZjRrf9jAf68tio9nX lxsFeKlWeQBIUJGPpXBhAvHCSA== X-Google-Smtp-Source: ABdhPJxkt3Ed7T7cJDKzmZe4wszjCxFAf1leiOQT2ICOasIg3V/FKQTBEDaG8y6oYK6K58aSdM216A== X-Received: by 2002:a05:6a00:a8d:b029:1ba:71d1:fe3c with SMTP id b13-20020a056a000a8db02901ba71d1fe3cmr21262398pfl.51.1612851797444; Mon, 08 Feb 2021 22:23:17 -0800 (PST) Received: from localhost ([2401:fa00:1:10:a106:46e1:a999:81df]) by smtp.gmail.com with UTF8SMTPSA id a8sm1160332pjs.40.2021.02.08.22.23.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 08 Feb 2021 22:23:16 -0800 (PST) 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 , Claire Chang Subject: [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Date: Tue, 9 Feb 2021 14:21:30 +0800 Message-Id: <20210209062131.2300005-14-tientzu@chromium.org> X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog In-Reply-To: <20210209062131.2300005-1-tientzu@chromium.org> References: <20210209062131.2300005-1-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 | 24 +++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt index e8d3096d922c..fc9a12c2f679 100644 --- a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt @@ -51,6 +51,20 @@ 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. - vendor specific string in the form ,[-] no-map (optional) - empty property - Indicates the operating system must not create a virtual mapping @@ -120,6 +134,11 @@ 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 +157,9 @@ 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>; + /* ... */ + }; };