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authorChristoph Hellwig <hch@lst.de>2019-07-26 09:26:40 +0200
committerChristoph Hellwig <hch@lst.de>2019-08-10 19:52:45 +0200
commit33dcb37cef741294b481f4d889a465b8091f11bf (patch)
tree129f9cde5b52cd77e04382c99ff0421aa862354b /arch/arm64/mm
parentd8ad55538abe443919e20e0bb996561bca9cad84 (diff)
dma-mapping: fix page attributes for dma_mmap_*
All the way back to introducing dma_common_mmap we've defaulted to mark the pages as uncached. But this is wrong for DMA coherent devices. Later on DMA_ATTR_WRITE_COMBINE also got incorrect treatment as that flag is only treated special on the alloc side for non-coherent devices. Introduce a new dma_pgprot helper that deals with the check for coherent devices so that only the remapping cases ever reach arch_dma_mmap_pgprot and we thus ensure no aliasing of page attributes happens, which makes the powerpc version of arch_dma_mmap_pgprot obsolete and simplifies the remaining ones. Note that this means arch_dma_mmap_pgprot is a bit misnamed now, but we'll phase it out soon. Fixes: 64ccc9c033c6 ("common: dma-mapping: add support for generic dma_mmap_* calls") Reported-by: Shawn Anastasio <shawn@anastas.io> Reported-by: Gavin Li <git@thegavinli.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64
Diffstat (limited to 'arch/arm64/mm')
-rw-r--r--arch/arm64/mm/dma-mapping.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 1d3f0b5a9940..bd2b039f43a6 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -14,9 +14,7 @@
pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
unsigned long attrs)
{
- if (!dev_is_dma_coherent(dev) || (attrs & DMA_ATTR_WRITE_COMBINE))
- return pgprot_writecombine(prot);
- return prot;
+ return pgprot_writecombine(prot);
}
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,