path: root/include/xen/arm/page-coherent.h
diff options
authorChristoph Hellwig <hch@lst.de>2022-04-22 06:37:57 +0200
committerChristoph Hellwig <hch@lst.de>2022-05-11 19:48:32 +0200
commit566fb90e050dfa2132340bbdab9533b727dda6f1 (patch)
tree04e47ee8436c65cf9a85cfa8a84e866a93ec2f12 /include/xen/arm/page-coherent.h
parentx86: remove cruft from <asm/dma-mapping.h> (diff)
swiotlb-xen: fix DMA_ATTR_NO_KERNEL_MAPPING on arm
swiotlb-xen uses very different ways to allocate coherent memory on x86 vs arm. On the former it allocates memory from the page allocator, while on the later it reuses the dma-direct allocator the handles the complexities of non-coherent DMA on arm platforms. Unfortunately the complexities of trying to deal with the two cases in the swiotlb-xen.c code lead to a bug in the handling of DMA_ATTR_NO_KERNEL_MAPPING on arm. With the DMA_ATTR_NO_KERNEL_MAPPING flag the coherent memory allocator does not actually allocate coherent memory, but just a DMA handle for some memory that is DMA addressable by the device, but which does not have to have a kernel mapping. Thus dereferencing the return value will lead to kernel crashed and memory corruption. Fix this by using the dma-direct allocator directly for arm, which works perfectly fine because on arm swiotlb-xen is only used when the domain is 1:1 mapped, and then simplifying the remaining code to only cater for the x86 case with DMA coherent device. Reported-by: Rahul Singh <Rahul.Singh@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Rahul Singh <rahul.singh@arm.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Rahul Singh <rahul.singh@arm.com>
Diffstat (limited to 'include/xen/arm/page-coherent.h')
1 files changed, 0 insertions, 20 deletions
diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h
deleted file mode 100644
index b9cc11e887ed..000000000000
--- a/include/xen/arm/page-coherent.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/dma-mapping.h>
-#include <asm/page.h>
-static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
- dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
- return dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
-static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
- void *cpu_addr, dma_addr_t dma_handle, unsigned long attrs)
- dma_direct_free(hwdev, size, cpu_addr, dma_handle, attrs);
-#endif /* _XEN_ARM_PAGE_COHERENT_H */