From 22ff38e850b7fc87bdcccbebe92c3e7764ffe389 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 23 Apr 2015 12:46:16 +0100 Subject: arm64: dma-mapping: always clear allocated buffers commit 6829e274a623187c24f7cfc0e3d35f25d087fcc5 upstream. Buffers allocated by dma_alloc_coherent() are always zeroed on Alpha, ARM (32bit), MIPS, PowerPC, x86/x86_64 and probably other architectures. It turned out that some drivers rely on this 'feature'. Allocated buffer might be also exposed to userspace with dma_mmap() call, so clearing it is desired from security point of view to avoid exposing random memory to userspace. This patch unifies dma_alloc_coherent() behavior on ARM64 architecture with other implementations by unconditionally zeroing allocated buffer. Signed-off-by: Marek Szyprowski [will: ported to 3.14.y] Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/dma-mapping.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 3974881388bb..b76159a153a5 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -54,8 +54,7 @@ static void *arm64_swiotlb_alloc_coherent(struct device *dev, size_t size, *dma_handle = phys_to_dma(dev, page_to_phys(page)); addr = page_address(page); - if (flags & __GFP_ZERO) - memset(addr, 0, size); + memset(addr, 0, size); return addr; } else { return swiotlb_alloc_coherent(dev, size, dma_handle, flags); -- cgit v1.2.3