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Tue, 12 May 2020 08:57:21 +0000 (GMT) From: Marek Szyprowski To: dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse Date: Tue, 12 May 2020 10:57:10 +0200 Message-Id: <20200512085710.14688-1-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprFKsWRmVeSWpSXmKPExsWy7djPc7qfUnbFGexpl7foPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HLlIZPFpsfXWC0u75rDZrH2yF12i4MfnrA6cHusmbeG 0WPvtwUsHtu/PWD1uN99nMlj85J6j9v/HjN7TL6xnNFj980GNo++LasYPT5vkgvgiuKySUnN ySxLLdK3S+DK+LZzG1vBXt+KU6vuszUwHrbuYuTkkBAwkbgwaxVbFyMXh5DACkaJdxf+MkM4 Xxgl3r+8wAThfGaUWNB8iBmm5fi0dYwQieWMEjMaW5ngWiZe6mUCqWITMJToetvFBmKLCLQy Spzo5QGxmQVmMEkcfV0KYgsLBEgs23iJpYuRg4NFQFViVi8HSJhXwFbiwO45TBDL5CVWbzgA dpKEwGR2iWVrZzNCJFwkLt/7wgZhC0u8Or6FHcKWkfi/cz4TREMzo8TDc2vZIZweRonLTTOg uq0l7pz7xQaymVlAU2L9Ln2IsKPE9wP7mUDCEgJ8EjfeCkLczCcxadt0Zogwr0RHmxBEtZrE rOPr4NYevHAJGkAeElvftoLZQgKxEnvPv2efwCg3C2HXAkbGVYziqaXFuempxcZ5qeV6xYm5 xaV56XrJ+bmbGIEp5vS/4193MO77k3SIUYCDUYmHt8NoZ5wQa2JZcWXuIUYJDmYlEd6WTKAQ b0piZVVqUX58UWlOavEhRmkOFiVxXuNFL2OFBNITS1KzU1MLUotgskwcnFINjPX9X0vnWHlZ N+2wu/i+vlg2R+lnzIYH74JmrnhSvvbu0td3rm18zc6ZIfDmbHjxjRUOF1urYo79f+Ct2DfL Vaqj89u8z4ZdL1giuDrdQx7xOwre99RhUvzJuSjXtKCmcrqT5NLffgZ+Z89kWXWKP9GOeRnM Ka60pOevtEFp1dPkZsNji9IPK7EUZyQaajEXFScCADFnKEItAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrPLMWRmVeSWpSXmKPExsVy+t/xe7qfUnbFGVw5xmTRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8eXKQyaLTY+vsVpc3jWHzWLtkbvsFgc/PGF14PZYM28N o8febwtYPLZ/e8Dqcb/7OJPH5iX1Hrf/PWb2mHxjOaPH7psNbB59W1YxenzeJBfAFaVnU5Rf WpKqkJFfXGKrFG1oYaRnaGmhZ2RiqWdobB5rZWSqpG9nk5Kak1mWWqRvl6CX8W3nNraCvb4V p1bdZ2tgPGzdxcjJISFgInF82jpGEFtIYCmjxN5mNoi4jMTJaQ2sELawxJ9rXUBxLqCaT4wS jxaeBkuwCRhKdL2FSIgIdDJKTOv+yA7iMAvMY5JY9PAQkMPBISzgJ7HsiBWIySKgKjGrlwOk l1fAVuLA7jlMEAvkJVZvOMA8gZFnASPDKkaR1NLi3PTcYiO94sTc4tK8dL3k/NxNjMDA3nbs 55YdjF3vgg8xCnAwKvHwdhjtjBNiTSwrrsw9xCjBwawkwtuSCRTiTUmsrEotyo8vKs1JLT7E aAq0eyKzlGhyPjDq8kriDU0NzS0sDc2NzY3NLJTEeTsEDsYICaQnlqRmp6YWpBbB9DFxcEo1 ME67I6ddHfPmeIlZ3GPhIvUXU9/9FasIe/zJqeXMPqft4R56tY9Tgm0+1+9YwT7Fyf6dqfny OoG5E4/rXDpa8fKo95OECfJ7i1yvXrv2mN3N9JSy1gbTfOXa6/whklk5Kr+LFsx/dXbtWtXF KgfWvl1S//qCpWX/k5Y7h59HW6w/21M54+eqM11KLMUZiYZazEXFiQD7wsNDggIAAA== X-CMS-MailID: 20200512085722eucas1p2fbaab30e49c9ddadc64b27db856e5921 X-Msg-Generator: CA X-RootMTR: 20200512085722eucas1p2fbaab30e49c9ddadc64b27db856e5921 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512085722eucas1p2fbaab30e49c9ddadc64b27db856e5921 References: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200512_015726_186806_17A1AAF7 X-CRM114-Status: GOOD ( 22.16 ) X-Spam-Score: -5.4 (-----) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-5.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [210.118.77.12 listed in list.dnswl.org] 0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [210.118.77.12 listed in wl.mailspike.net] -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.0 RCVD_IN_MSPIKE_WL Mailspike good senders -0.2 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bartlomiej Zolnierkiewicz , David Airlie , Daniel Vetter , Robin Murphy , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, Marek Szyprowski MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Dear All, During the Exynos DRM GEM rework and fixing the issues in the. drm_prime_sg_to_page_addr_arrays() function [1] I've noticed that most drivers in DRM framework incorrectly use nents and orig_nents entries of the struct sg_table. In case of the most DMA-mapping implementations exchanging those two entries or using nents for all loops on the scatterlist is harmless, because they both have the same value. There exists however a DMA-mapping implementations, for which such incorrect usage breaks things. The nents returned by dma_map_sg() might be lower than the nents passed as its parameter and this is perfectly fine. DMA framework or IOMMU is allowed to join consecutive chunks while mapping if such operation is supported by the underlying HW (bus, bridge, IOMMU, etc). Example of the case where dma_map_sg() might return 1 'DMA' chunk for the 4 'physical' pages is described here [2] The DMA-mapping framework documentation [3] states that dma_map_sg() returns the numer of the created entries in the DMA address space. However the subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg must be called with the original number of entries passed to dma_map_sg. The common pattern in DRM drivers were to assign the dma_map_sg() return value to sg_table->nents and use that value for the subsequent calls to dma_sync_sg_* or dma_unmap_sg functions. Also the code iterated over nents times to access the pages stored in the processed scatterlist, while it should use orig_nents as the numer of the page entries. I've tried to identify all such incorrect usage of sg_table->nents and this is a result of my research. It looks that the incorrect pattern has been copied over the many drivers mainly in the DRM subsystem. Too bad in most cases it even worked correctly if the system used a simple, linear DMA-mapping implementation, for which swapping nents and orig_nents doesn't make any difference. To avoid similar issues in the future, I've introduced a common wrappers for DMA-mapping calls, which operate directly on the sg_table objects. I've also added wrappers for iterating over the scatterlists stored in the sg_table objects and applied them where possible. This, together with some common DRM prime helpers, allowed me to almost get rid of all nents/orig_nents usage in the drivers. I hope that such change makes the code robust, easier to follow and copy/paste safe. The biggest TODO is DRM/i915 driver and I don't feel brave enough to fix it fully. The driver creatively uses sg_table->orig_nents to store the size of the allocate scatterlist and ignores the number of the entries returned by dma_map_sg function. In this patchset I only fixed the sg_table objects exported by dmabuf related functions. I hope that I didn't break anything there. Patches are based on top of Linux next-20200511. Best regards, Marek Szyprowski References: [1] https://lkml.org/lkml/2020/3/27/555. [2] https://lkml.org/lkml/2020/3/29/65 [3] Documentation/DMA-API-HOWTO.txt Changelog: v4: - added for_each_sgtable_* wrappers and applied where possible - added drm_prime_get_contiguous_size() and applied where possible - applied drm_prime_sg_to_page_addr_arrays() where possible to remove page extraction from sg_table objects - added documentation for the introduced wrappers - improved patches description a bit v3: https://lore.kernel.org/dri-devel/20200505083926.28503-1-m.szyprowski@samsung.com/ - introduce dma_*_sgtable_* wrappers and use them in all patches v2: https://lore.kernel.org/linux-iommu/c01c9766-9778-fd1f-f36e-2dc7bd376ba4@arm.com/T/ - dropped most of the changes to drm/i915 - added fixes for rcar-du, xen, media and ion - fixed a few issues pointed by kbuild test robot - added wide cc: list for each patch v1: https://lore.kernel.org/linux-iommu/c01c9766-9778-fd1f-f36e-2dc7bd376ba4@arm.com/T/ - initial version Patch summary: Marek Szyprowski (38): dma-mapping: add generic helpers for mapping sgtable objects scatterlist: add generic wrappers for iterating over sgtable objects iommu: add generic helper for mapping sgtable objects drm: prime: add common helper to check scatterlist contiguity drm: prime: use sgtable iterators in drm_prime_sg_to_page_addr_arrays() drm: core: fix common struct sg_table related issues drm: amdgpu: fix common struct sg_table related issues drm: armada: fix common struct sg_table related issues drm: etnaviv: fix common struct sg_table related issues drm: exynos: use common helper for a scatterlist contiguity check drm: exynos: fix common struct sg_table related issues drm: i915: fix common struct sg_table related issues drm: lima: fix common struct sg_table related issues drm: mediatek: use common helper for a scatterlist contiguity check drm: mediatek: use common helper for extracting pages array drm: msm: fix common struct sg_table related issues drm: omapdrm: use common helper for extracting pages array drm: omapdrm: fix common struct sg_table related issues drm: panfrost: fix common struct sg_table related issues drm: radeon: fix common struct sg_table related issues drm: rockchip: use common helper for a scatterlist contiguity check drm: rockchip: fix common struct sg_table related issues drm: tegra: fix common struct sg_table related issues drm: v3d: fix common struct sg_table related issues drm: virtio: fix common struct sg_table related issues drm: vmwgfx: fix common struct sg_table related issues xen: gntdev: fix common struct sg_table related issues drm: host1x: fix common struct sg_table related issues drm: rcar-du: fix common struct sg_table related issues dmabuf: fix common struct sg_table related issues staging: ion: remove dead code staging: ion: fix common struct sg_table related issues staging: tegra-vde: fix common struct sg_table related issues misc: fastrpc: fix common struct sg_table related issues rapidio: fix common struct sg_table related issues samples: vfio-mdev/mbochs: fix common struct sg_table related issues media: pci: fix common ALSA DMA-mapping related codes videobuf2: use sgtable-based scatterlist wrappers drivers/dma-buf/heaps/heap-helpers.c | 13 ++-- drivers/dma-buf/udmabuf.c | 7 +- drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 6 +- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 9 +-- drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 8 +- drivers/gpu/drm/armada/armada_gem.c | 12 +-- drivers/gpu/drm/drm_cache.c | 2 +- drivers/gpu/drm/drm_gem_cma_helper.c | 23 +----- drivers/gpu/drm/drm_gem_shmem_helper.c | 14 ++-- drivers/gpu/drm/drm_prime.c | 86 ++++++++++++---------- drivers/gpu/drm/etnaviv/etnaviv_gem.c | 12 ++- drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 13 +--- drivers/gpu/drm/exynos/exynos_drm_g2d.c | 10 +-- drivers/gpu/drm/exynos/exynos_drm_gem.c | 23 +----- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 11 +-- drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 7 +- drivers/gpu/drm/lima/lima_gem.c | 11 ++- drivers/gpu/drm/lima/lima_vm.c | 5 +- drivers/gpu/drm/mediatek/mtk_drm_gem.c | 34 ++------- drivers/gpu/drm/msm/msm_gem.c | 13 ++-- drivers/gpu/drm/msm/msm_gpummu.c | 14 ++-- drivers/gpu/drm/msm/msm_iommu.c | 2 +- drivers/gpu/drm/omapdrm/omap_gem.c | 20 ++--- drivers/gpu/drm/panfrost/panfrost_gem.c | 4 +- drivers/gpu/drm/panfrost/panfrost_mmu.c | 7 +- drivers/gpu/drm/radeon/radeon_ttm.c | 11 ++- drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 3 +- drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 42 +++-------- drivers/gpu/drm/tegra/gem.c | 27 +++---- drivers/gpu/drm/tegra/plane.c | 15 ++-- drivers/gpu/drm/v3d/v3d_mmu.c | 17 ++--- drivers/gpu/drm/virtio/virtgpu_object.c | 36 +++++---- drivers/gpu/drm/virtio/virtgpu_vq.c | 12 ++- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 17 +---- drivers/gpu/host1x/job.c | 22 ++---- .../media/common/videobuf2/videobuf2-dma-contig.c | 41 +++++------ drivers/media/common/videobuf2/videobuf2-dma-sg.c | 32 +++----- drivers/media/common/videobuf2/videobuf2-vmalloc.c | 12 +-- drivers/media/pci/cx23885/cx23885-alsa.c | 2 +- drivers/media/pci/cx25821/cx25821-alsa.c | 2 +- drivers/media/pci/cx88/cx88-alsa.c | 2 +- drivers/media/pci/saa7134/saa7134-alsa.c | 2 +- drivers/media/platform/vsp1/vsp1_drm.c | 8 +- drivers/misc/fastrpc.c | 4 +- drivers/rapidio/devices/rio_mport_cdev.c | 8 +- drivers/staging/android/ion/ion.c | 25 +++---- drivers/staging/android/ion/ion.h | 1 - drivers/staging/android/ion/ion_heap.c | 53 ++++--------- drivers/staging/android/ion/ion_system_heap.c | 2 +- drivers/staging/media/tegra-vde/iommu.c | 4 +- drivers/xen/gntdev-dmabuf.c | 13 ++-- include/drm/drm_prime.h | 2 + include/linux/dma-mapping.h | 79 ++++++++++++++++++++ include/linux/iommu.h | 16 ++++ include/linux/scatterlist.h | 50 ++++++++++++- samples/vfio-mdev/mbochs.c | 3 +- 56 files changed, 452 insertions(+), 477 deletions(-)