arm64: dma-mapping: always clear allocated buffers

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commit 6829e274a6 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>

...

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Marek Szyprowski 2015-04-23 12:46:16 +01:00 • committed by Greg Kroah-Hartman

parent 762167f98c

commit 22ff38e850

1 changed files with 1 additions and 2 deletions

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arch/arm64/mm/dma-mapping.c

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