arm64: dma-mapping: always clear allocated buffers
commit 6829e274 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> Signed-off-by: Will Deacon <will.deacon@arm.com> [ luis: backported to 3.16: - dropped changes to __alloc_from_pool() which doesn't exist in 3.16 ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Showing
Please register or sign in to comment