From a929f067a88f0f9a2b02e328f746007f645fa920 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Tue, 12 Jun 2018 13:08:40 +0200 Subject: [PATCH] arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag [ Upstream commit dd65a941f6ba473a5cb9d013d57fa43b48450a04 ] 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, because dma_alloc_from_contiguous() doesn't honor __GFP_ZERO flag. This patch fixes this issue. For more information on clearing buffers allocated by dma_alloc_* functions, see commit 6829e274a623 ("arm64: dma-mapping: always clear allocated buffers"). Fixes: 44176bb38fa4 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU") Signed-off-by: Marek Szyprowski Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- 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 614af88..58470b1 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); -- 2.7.4