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| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2015-04-23 12:46:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-03 19:49:04 -0700 |
| commit | 22ff38e850b7fc87bdcccbebe92c3e7764ffe389 (patch) | |
| tree | 2cd8d9e51395cb1565e315647842e0f966aa5185 | |
| parent | 762167f98c6aa8d47c801f8b6ac20bf30d786a4b (diff) | |
| download | lwn-22ff38e850b7fc87bdcccbebe92c3e7764ffe389.tar.gz lwn-22ff38e850b7fc87bdcccbebe92c3e7764ffe389.zip | |
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 <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>
| -rw-r--r-- | arch/arm64/mm/dma-mapping.c | 3 |
1 files changed, 1 insertions, 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); |