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| author | Christoph Hellwig <hch@lst.de> | 2019-07-26 09:26:40 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2019-08-10 19:52:45 +0200 |
| commit | 33dcb37cef741294b481f4d889a465b8091f11bf (patch) | |
| tree | 129f9cde5b52cd77e04382c99ff0421aa862354b /arch/arm64/mm | |
| parent | d8ad55538abe443919e20e0bb996561bca9cad84 (diff) | |
| download | linux-33dcb37cef741294b481f4d889a465b8091f11bf.tar.gz linux-33dcb37cef741294b481f4d889a465b8091f11bf.tar.bz2 linux-33dcb37cef741294b481f4d889a465b8091f11bf.zip | |
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.c | 4 |
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, |