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| author | Christoph Hellwig <hch@lst.de> | 2020-02-21 12:35:05 -0800 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-03-16 10:48:12 +0100 |
| commit | 999a5d1203baa7cff00586361feae263ee3f23a5 (patch) | |
| tree | b04c578a71b961394e7fe87567684bf0caefbe8b | |
| parent | fa7e2247c5729f990c7456fe09f3af99c8f2571b (diff) | |
| download | lwn-999a5d1203baa7cff00586361feae263ee3f23a5.tar.gz lwn-999a5d1203baa7cff00586361feae263ee3f23a5.zip | |
dma-direct: provide a arch_dma_clear_uncached hook
This allows the arch code to reset the page tables to cached access when
freeing a dma coherent allocation that was set to uncached using
arch_dma_set_uncached.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
| -rw-r--r-- | arch/Kconfig | 7 | ||||
| -rw-r--r-- | include/linux/dma-noncoherent.h | 1 | ||||
| -rw-r--r-- | kernel/dma/direct.c | 2 |
3 files changed, 10 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 090cfe0c82a7..c26302f90c96 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -255,6 +255,13 @@ config ARCH_HAS_SET_DIRECT_MAP config ARCH_HAS_DMA_SET_UNCACHED bool +# +# Select if the architectures provides the arch_dma_clear_uncached symbol +# to undo an in-place page table remap for uncached access. +# +config ARCH_HAS_DMA_CLEAR_UNCACHED + bool + # Select if arch init_task must go in the __init_task_data section config ARCH_TASK_STRUCT_ON_STACK bool diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h index 1a4039506673..b59f1b6be3e9 100644 --- a/include/linux/dma-noncoherent.h +++ b/include/linux/dma-noncoherent.h @@ -109,5 +109,6 @@ static inline void arch_dma_prep_coherent(struct page *page, size_t size) #endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */ void *arch_dma_set_uncached(void *addr, size_t size); +void arch_dma_clear_uncached(void *addr, size_t size); #endif /* _LINUX_DMA_NONCOHERENT_H */ diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index baf4e93735c3..412f560dc69f 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -231,6 +231,8 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) vunmap(cpu_addr); + else if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) + arch_dma_clear_uncached(cpu_addr, size); dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size); } |