From e3ad50b8507368747c088cdbd9107ec6d6477da0 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Tue, 12 Jun 2018 13:08:40 +0200
Subject: [PATCH 17/20] arm64: dma-mapping: clear buffers allocated with
FORCE_CONTIGUOUS flag
Git-commit: dd65a941f6ba473a5cb9d013d57fa43b48450a04
Patch-mainline: v4.18-rc2
References: bsc#1106902
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 6829e274a623 ("arm64: dma-mapping: always clear allocated
buffers").
Fixes: 44176bb38fa4 ("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>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
arch/arm64/mm/dma-mapping.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 3216e098c058..69535c3a5303 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -639,13 +639,14 @@ 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);
--
2.11.0