From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Mon, 11 Jun 2018 07:13:40 +0200 Subject: [PATCH] arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag References: Message-ID: <20180611051340.9024-1-m.szyprowski@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org dma_alloc_*() buffers might be exposed to userspace via mmap() call, so they should be cleared on allocation. In case of IOMMU-based dma-mapping implementation such buffer clearing was missing in the code path for DMA_ATTR_FORCE_CONTIGUOUS flag handling. This patch fixes this issue. For more information on clearing buffers allocated by dma_alloc_* functions, see commit 44176bb38fa4 ("arm64: dma-mapping: always clear allocated buffers"). Fixes: 44176bb38fa4 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU") Signed-off-by: Marek Szyprowski --- arch/arm64/mm/dma-mapping.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 632d32109755..aa0037a3185f 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -629,13 +629,14 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size, size >> PAGE_SHIFT); return NULL; } - if (!coherent) - __dma_flush_area(page_to_virt(page), iosize); - addr = dma_common_contiguous_remap(page, size, VM_USERMAP, prot, __builtin_return_address(0)); - if (!addr) { + if (addr) { + memset(addr, 0, size); + if (!coherent) + __dma_flush_area(page_to_virt(page), iosize); + } else { iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs); dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); -- 2.17.1