forked from Minki/linux
arm64: dma-mapping: always clear allocated buffers
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. Cc: <stable@vger.kernel.org> # v3.14+ Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
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@ -67,8 +67,7 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags)
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*ret_page = phys_to_page(phys);
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ptr = (void *)val;
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if (flags & __GFP_ZERO)
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memset(ptr, 0, size);
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memset(ptr, 0, size);
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}
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return ptr;
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@ -113,8 +112,7 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
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*dma_handle = phys_to_dma(dev, page_to_phys(page));
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addr = page_address(page);
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if (flags & __GFP_ZERO)
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memset(addr, 0, size);
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memset(addr, 0, size);
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return addr;
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} else {
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return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
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