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| author | Christoph Hellwig | 2019-06-03 08:43:51 +0200 |
|---|---|---|
| committer | Christoph Hellwig | 2019-06-03 16:00:08 +0200 |
| commit | c30700db9eaabb35e0b123301df35a6846e6b6b4 (patch) | |
| tree | 96e4e6018c0b6e92289aee5093082c6322ab7abf | |
| parent | au1100fb: fix DMA API abuse (diff) | |
| download | kernel-qcow2-linux-c30700db9eaabb35e0b123301df35a6846e6b6b4.tar.gz kernel-qcow2-linux-c30700db9eaabb35e0b123301df35a6846e6b6b4.tar.xz kernel-qcow2-linux-c30700db9eaabb35e0b123301df35a6846e6b6b4.zip | |
dma-direct: provide generic support for uncached kernel segments
A few architectures support uncached kernel segments. In that case we get
an uncached mapping for a given physica address by using an offset in the
uncached segement. Implement support for this scheme in the generic
dma-direct code instead of duplicating it in arch hooks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | arch/Kconfig | 8 | ||||
| -rw-r--r-- | include/linux/dma-noncoherent.h | 3 | ||||
| -rw-r--r-- | kernel/dma/direct.c | 17 |
3 files changed, 26 insertions, 2 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index c47b328eada0..e8d19c3cb91f 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -260,6 +260,14 @@ config ARCH_HAS_SET_MEMORY config ARCH_HAS_SET_DIRECT_MAP bool +# +# Select if arch has an uncached kernel segment and provides the +# uncached_kernel_address / cached_kernel_address symbols to use it +# +config ARCH_HAS_UNCACHED_SEGMENT + select ARCH_HAS_DMA_PREP_COHERENT + 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 9741767e400f..7e0126a04e02 100644 --- a/include/linux/dma-noncoherent.h +++ b/include/linux/dma-noncoherent.h @@ -80,4 +80,7 @@ static inline void arch_dma_prep_coherent(struct page *page, size_t size) } #endif /* CONFIG_ARCH_HAS_DMA_PREP_COHERENT */ +void *uncached_kernel_address(void *addr); +void *cached_kernel_address(void *addr); + #endif /* _LINUX_DMA_NONCOHERENT_H */ diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 0816c1e8b05a..b67f0aa08aa3 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -158,6 +158,13 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, *dma_handle = phys_to_dma(dev, page_to_phys(page)); } memset(ret, 0, size); + + if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && + !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) { + arch_dma_prep_coherent(page, size); + ret = uncached_kernel_address(ret); + } + return ret; } @@ -173,13 +180,18 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, if (force_dma_unencrypted()) set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order); + + if (IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && + !dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_NON_CONSISTENT)) + cpu_addr = cached_kernel_address(cpu_addr); __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr)); } void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { - if (!dev_is_dma_coherent(dev)) + if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && + !dev_is_dma_coherent(dev)) return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs); } @@ -187,7 +199,8 @@ void *dma_direct_alloc(struct device *dev, size_t size, void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { - if (!dev_is_dma_coherent(dev)) + if (!IS_ENABLED(CONFIG_ARCH_HAS_UNCACHED_SEGMENT) && + !dev_is_dma_coherent(dev)) arch_dma_free(dev, size, cpu_addr, dma_addr, attrs); else dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs); |