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authorMarek Szyprowski <m.szyprowski@samsung.com>2015-04-23 12:46:16 +0100
committerWill Deacon <will.deacon@arm.com>2015-04-27 11:39:50 +0100
commit6829e274a623187c24f7cfc0e3d35f25d087fcc5 (patch)
treea6ca873b29878ee7bc8c328af8a64bae0f49a37e /arch
parent6544e67bfb1bf55bcf3c0f6b37631917e9acfb74 (diff)
downloadlinux-6829e274a623187c24f7cfc0e3d35f25d087fcc5.tar.bz2
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/mm/dma-mapping.c6
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);