--- /dev/null
+From 6829e274a623187c24f7cfc0e3d35f25d087fcc5 Mon Sep 17 00:00:00 2001
+From: Marek Szyprowski <m.szyprowski@samsung.com>
+Date: Thu, 23 Apr 2015 12:46:16 +0100
+Subject: arm64: dma-mapping: always clear allocated buffers
+
+From: Marek Szyprowski <m.szyprowski@samsung.com>
+
+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 <m.szyprowski@samsung.com>
+[will: ported to 3.14.y]
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/arm64/mm/dma-mapping.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+--- a/arch/arm64/mm/dma-mapping.c
++++ b/arch/arm64/mm/dma-mapping.c
+@@ -54,8 +54,7 @@ static void *arm64_swiotlb_alloc_coheren
+
+ *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);