From: Claire Chang <tientzu@chromium.org>
To: Rob Herring <robh+dt@kernel.org>,
mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
boris.ostrovsky@oracle.com, jgross@suse.com,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>
Cc: benh@kernel.crashing.org, paulus@samba.org,
"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
sstabellini@kernel.org, Robin Murphy <robin.murphy@arm.com>,
grant.likely@arm.com, xypron.glpk@gmx.de,
Thierry Reding <treding@nvidia.com>,
mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org,
Greg KH <gregkh@linuxfoundation.org>,
Saravana Kannan <saravanak@google.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
heikki.krogerus@linux.intel.com,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Randy Dunlap <rdunlap@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
linux-devicetree <devicetree@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xenproject.org,
Nicolas Boichat <drinkcat@chromium.org>,
Jim Quinlan <james.quinlan@broadcom.com>,
Claire Chang <tientzu@chromium.org>
Subject: [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool
Date: Tue, 9 Feb 2021 14:21:30 +0800 [thread overview]
Message-ID: <20210209062131.2300005-14-tientzu@chromium.org> (raw)
In-Reply-To: <20210209062131.2300005-1-tientzu@chromium.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 <tientzu@chromium.org>
---
.../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 <vendor>,[<device>-]<usage>
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>;
+ /* ... */
+ };
};
--
2.30.0.478.g8a0d178c01-goog
next prev parent reply other threads:[~2021-02-09 6:23 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 6:21 [PATCH v4 00/14] Restricted DMA Claire Chang
2021-02-09 6:21 ` [PATCH v4 01/14] swiotlb: Remove external access to io_tlb_start Claire Chang
2021-02-09 8:40 ` Christoph Hellwig
2021-02-09 6:21 ` [PATCH v4 02/14] swiotlb: Move is_swiotlb_buffer() to swiotlb.c Claire Chang
2021-02-09 6:21 ` [PATCH v4 03/14] swiotlb: Add struct swiotlb Claire Chang
2021-02-09 6:21 ` [PATCH v4 04/14] swiotlb: Refactor swiotlb_late_init_with_tbl Claire Chang
2021-02-09 6:21 ` [PATCH v4 05/14] swiotlb: Add DMA_RESTRICTED_POOL Claire Chang
2021-02-09 6:21 ` [PATCH v4 06/14] swiotlb: Add restricted DMA pool Claire Chang
2021-02-09 6:21 ` [PATCH v4 07/14] swiotlb: Update swiotlb API to gain a struct device argument Claire Chang
2021-02-09 6:21 ` [PATCH v4 08/14] swiotlb: Use restricted DMA pool if available Claire Chang
2021-02-09 6:21 ` [PATCH v4 09/14] swiotlb: Refactor swiotlb_tbl_{map,unmap}_single Claire Chang
2021-02-09 6:21 ` [PATCH v4 10/14] dma-direct: Add a new wrapper __dma_direct_free_pages() Claire Chang
2021-02-09 6:21 ` [PATCH v4 11/14] swiotlb: Add is_dev_swiotlb_force() Claire Chang
2021-02-09 6:21 ` [PATCH v4 12/14] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-02-26 4:17 ` Claire Chang
2021-02-26 5:17 ` Christoph Hellwig
2021-02-26 9:35 ` Claire Chang
2021-02-09 6:21 ` Claire Chang [this message]
2021-03-10 16:07 ` [PATCH v4 13/14] dt-bindings: of: Add restricted DMA pool Will Deacon
2021-03-10 21:40 ` Rob Herring
2021-03-11 5:04 ` Florian Fainelli
2021-02-09 6:21 ` [PATCH v4 14/14] of: Add plumbing for " Claire Chang
2021-04-22 8:20 ` [PATCH v4 00/14] Restricted DMA Claire Chang
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