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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 /include
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 'include')
-rw-r--r--include/linux/dma-noncoherent.h13
1 files changed, 9 insertions, 4 deletions
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
index 3813211a9aad..0bff3d7fac92 100644
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -42,13 +42,18 @@ void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs);
long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr,
dma_addr_t dma_addr);
-
-#ifdef CONFIG_ARCH_HAS_DMA_MMAP_PGPROT
pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
unsigned long attrs);
+
+#ifdef CONFIG_MMU
+pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs);
#else
-# define arch_dma_mmap_pgprot(dev, prot, attrs) pgprot_noncached(prot)
-#endif
+static inline pgprot_t dma_pgprot(struct device *dev, pgprot_t prot,
+ unsigned long attrs)
+{
+ return prot; /* no protection bits supported without page tables */
+}
+#endif /* CONFIG_MMU */
#ifdef CONFIG_DMA_NONCOHERENT_CACHE_SYNC
void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size,