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Tue, 5 May 2020 09:43:09 +0100 (BST) Received: from eusmtrp1.samsung.com (unknown [182.198.249.138]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20200505084308eucas1p1aa040c3ae325a6c7d92f956b1f5aad0d~MFUz90wG30752907529eucas1p15; Tue, 5 May 2020 08:43:08 +0000 (GMT) Received: from eusmgms2.samsung.com (unknown [182.198.249.180]) by eusmtrp1.samsung.com (KnoxPortal) with ESMTP id 20200505084308eusmtrp1f6d10f1165c581cda2504a3b128040e8~MFUz9FVZm0716407164eusmtrp12; Tue, 5 May 2020 08:43:08 +0000 (GMT) X-AuditID: cbfec7f4-0cbff7000001ed07-a8-5eb1271dbcb6 Received: from eusmtip1.samsung.com ( [203.254.199.221]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id 01.A0.07950.C1721BE5; Tue, 5 May 2020 09:43:08 +0100 (BST) Received: from AMDC2765.digital.local (unknown [106.120.51.73]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20200505084308eusmtip13a12b282487c6faf89fcb2ab4db393d5~MFUzetK7V0070700707eusmtip1g; Tue, 5 May 2020 08:43:08 +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 Cc: Marek Szyprowski , Christoph Hellwig , Robin Murphy , Bartlomiej Zolnierkiewicz , linux-arm-kernel@lists.infradead.org, David Airlie , Daniel Vetter Subject: [PATCH v3 00/25] DRM: fix struct sg_table nents vs. orig_nents misuse Date: Tue, 5 May 2020 10:43:00 +0200 Message-Id: <20200505083926.28503-1-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprJKsWRmVeSWpSXmKPExsWy7djPc7qy6hvjDHbul7boPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HLlIZPFpsfXWC0u75rDZrH2yF12i4MfnrA6cHusmbeG 0WPvtwUsHtu/PWD1uN99nMlj85J6j9v/HjN7TL6xnNFj980GNo++LasYPT5vkgvgiuKySUnN ySxLLdK3S+DK2LXuA2PBPsuKno1r2RsYL+t0MXJySAiYSLxc/Zuti5GLQ0hgBaPEjpefmUAS QgJfGCX+r3aESHxmlJg7+TcLTMfdy8tYIBLLGSX2XG2HagfqeLjiNlg7m4ChRNfbLjYQW0Sg lVHiRC8PiM0sMINJ4ujrUhBbWCBA4sjX6WBTWQRUJR43tYDZvAK2Ev37ZrNDbJOXWL3hADPI AgmB6ewS2/vOQJ3hItHYc4MNwhaWeHV8C1SDjMTpyT0sEA3NQBedW8sO4fQwSlxumsEIUWUt cefcL6BuDqCTNCXW79KHCDtKPG29wAwSlhDgk7jxVhDiaD6JSdumQ4V5JTrahCCq1SRmHV8H t/bghUvMELaHxPtbLWDDhQRiJRY89ZnAKDcLYdUCRsZVjOKppcW56anFRnmp5XrFibnFpXnp esn5uZsYgQnm9L/jX3Yw7vqTdIhRgINRiYc34vP6OCHWxLLiytxDjBIczEoivMt+bIgT4k1J rKxKLcqPLyrNSS0+xCjNwaIkzmu86GWskEB6YklqdmpqQWoRTJaJg1OqgXHzrvouv+pGg5nb TN/NX2Nj9WFhafAfFu7VIl9C1/q03VfMlDy5Um0aq90ftgsXlPLXqQYtf+v2Ul+mqmrT366W j+KzpII3/Zx1+TarFUdZcr+g5V2F3Ncyta8OnJ+g4X4ope732cbydYntszvWPpd+Ev93ve/z xbnHyzqvfedsNu2s3zbXxU+JpTgj0VCLuag4EQCuXNZLLAMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrILMWRmVeSWpSXmKPExsVy+t/xu7oy6hvjDJYdsLDoPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HLlIZPFpsfXWC0u75rDZrH2yF12i4MfnrA6cHusmbeG 0WPvtwUsHtu/PWD1uN99nMlj85J6j9v/HjN7TL6xnNFj980GNo++LasYPT5vkgvgitKzKcov LUlVyMgvLrFVija0MNIztLTQMzKx1DM0No+1MjJV0rezSUnNySxLLdK3S9DL2LXuA2PBPsuK no1r2RsYL+t0MXJySAiYSNy9vIyli5GLQ0hgKaPE4x1TWSESMhInpzVA2cISf651sUEUfWKU 6Hu/hR0kwSZgKNH1FiIhItDJKDGt+yM7iMMsMI9JYtHDQ0AOB4ewgJ/E0/9JIA0sAqoSj5ta WEBsXgFbif59s9khNshLrN5wgHkCI88CRoZVjCKppcW56bnFRnrFibnFpXnpesn5uZsYgcG9 7djPLTsYu94FH2IU4GBU4uHd8HV9nBBrYllxZe4hRgkOZiUR3mU/NsQJ8aYkVlalFuXHF5Xm pBYfYjQFWj6RWUo0OR8YeXkl8YamhuYWlobmxubGZhZK4rwdAgdjhATSE0tSs1NTC1KLYPqY ODilGhjF2hdPaUzmDRDJ/dU4qe7Sm9ki/5k/bQgxeBCwK+ZlsEvCg5p/mkH3tfXURMLOX1c3 v1T5Lts09M33JW6TduXmiS40PRi3Se5LW2lE5j+u2+EZKxuC+Nwe/3/dKftFuF9FN7Hw1QmR v1Uqqp9mCKYzb4j6dORgaWvwxeSNCzqO7BIvjOlZ5KLEUpyRaKjFXFScCADCUtXChAIAAA== X-CMS-MailID: 20200505084308eucas1p1aa040c3ae325a6c7d92f956b1f5aad0d X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20200505084308eucas1p1aa040c3ae325a6c7d92f956b1f5aad0d X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200505084308eucas1p1aa040c3ae325a6c7d92f956b1f5aad0d References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.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 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 dma-mapping wrappers, which operate directly on the sg_table objects. 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-20200504. 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: v3: - 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 (25): dma-mapping: add generic helpers for mapping sgtable objects 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: 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: msm: 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: fix common struct sg_table related issues drm: tegra: 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: 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 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/armada/armada_gem.c | 10 ++++---- drivers/gpu/drm/drm_cache.c | 2 +- drivers/gpu/drm/drm_gem_shmem_helper.c | 14 +++++++---- drivers/gpu/drm/drm_prime.c | 13 +++++----- drivers/gpu/drm/etnaviv/etnaviv_gem.c | 12 ++++----- drivers/gpu/drm/exynos/exynos_drm_g2d.c | 9 +++---- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 13 ++++------ drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 7 +++--- drivers/gpu/drm/lima/lima_gem.c | 11 +++++--- drivers/gpu/drm/msm/msm_gem.c | 13 ++++------ drivers/gpu/drm/msm/msm_iommu.c | 2 +- drivers/gpu/drm/panfrost/panfrost_gem.c | 4 +-- drivers/gpu/drm/panfrost/panfrost_mmu.c | 5 ++-- drivers/gpu/drm/radeon/radeon_ttm.c | 11 ++++---- drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 26 +++++++++---------- drivers/gpu/drm/tegra/gem.c | 27 ++++++++------------ drivers/gpu/drm/tegra/plane.c | 15 ++++------- drivers/gpu/drm/virtio/virtgpu_object.c | 17 ++++++------- drivers/gpu/drm/virtio/virtgpu_vq.c | 10 +++----- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 17 +++---------- drivers/gpu/host1x/job.c | 22 ++++++---------- 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 | 9 ++++--- 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_heap.c | 6 ++--- drivers/staging/android/ion/ion_system_heap.c | 2 +- drivers/staging/media/tegra-vde/iommu.c | 4 +-- drivers/xen/gntdev-dmabuf.c | 7 +++--- include/linux/dma-mapping.h | 32 ++++++++++++++++++++++++ include/linux/iommu.h | 6 +++++ samples/vfio-mdev/mbochs.c | 3 ++- 40 files changed, 202 insertions(+), 207 deletions(-) -- 1.9.1