Commit dd65a941 authored Jun 12, 2018 by Marek Szyprowski Committed by Catalin Marinas Jun 19, 2018

arm64: dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag

dma_alloc_*() buffers might be exposed to userspace via mmap() call, so
they should be cleared on allocation. In case of IOMMU-based dma-mapping
implementation such buffer clearing was missing in the code path for
DMA_ATTR_FORCE_CONTIGUOUS flag handling, because dma_alloc_from_contiguous()
doesn't honor __GFP_ZERO flag. This patch fixes this issue. For more
information on clearing buffers allocated by dma_alloc_* functions,
see commit 6829e274 ("arm64: dma-mapping: always clear allocated
buffers").

Fixes: 44176bb3 ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent ce397d21

arch/arm64/mm/dma-mapping.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -583,13 +583,14 @@ static void __iommu_alloc_attrs(struct device dev, size_t size,
		size >> PAGE_SHIFT);
		return NULL;
		}
		if (!coherent)
		__dma_flush_area(page_to_virt(page), iosize);

		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
		prot,
		__builtin_return_address(0));
		if (!addr) {
		if (addr) {
		memset(addr, 0, size);
		if (!coherent)
		__dma_flush_area(page_to_virt(page), iosize);
		} else {
		iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
		dma_release_from_contiguous(dev, page,
		size >> PAGE_SHIFT);