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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> | 2015-05-13 05:14:26 -0700 |
| commit | 41e45229f0a528a17ea7e36e9164b04fd071b751 (patch) | |
| tree | 282604c489c9e8b84dd40d1a5f15ec653a052ff8 | |
| parent | 9b19c50bff3747129752fa7883cf9a8a7d9e96b2 (diff) | |
| download | lwn-41e45229f0a528a17ea7e36e9164b04fd071b751.tar.gz lwn-41e45229f0a528a17ea7e36e9164b04fd071b751.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>
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 | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index ef7d112f5ce0..e0f14ee26b68 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -67,8 +67,7 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags) *ret_page = phys_to_page(phys); ptr = (void *)val; - if (flags & __GFP_ZERO) - memset(ptr, 0, size); + memset(ptr, 0, size); } return ptr; @@ -113,8 +112,7 @@ static void *__dma_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); |