From 0a2980a12bb4f509168f6721e99d6d1ee6099f60 Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Wed, 16 Jan 2013 18:23:19 -0800 Subject: [PATCH] ARM: dma-mapping: Allow highmem pages to not have a mapping The DMA_ATTR_NO_KERNEL_MAPPING is used to make sure that CMA pages have no kernel mapping. Add support to make sure that highmem pages have no mapping. Change-Id: Ife76df126ecfedf0dba81a35e0de8a1787355b3d Signed-off-by: Laura Abbott Signed-off-by: Rohit Vaswani --- arch/arm/mm/dma-mapping.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 5efeaac2fc4f..dd7820f5110a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -333,10 +333,10 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot, prot, caller); } -static void __dma_free_remap(void *cpu_addr, size_t size) +static void __dma_free_remap(void *cpu_addr, size_t size, bool no_warn) { dma_common_free_remap(cpu_addr, size, - VM_ARM_DMA_CONSISTENT | VM_USERMAP); + VM_ARM_DMA_CONSISTENT | VM_USERMAP, no_warn); } #define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K @@ -578,6 +578,7 @@ static int __free_from_pool(void *start, size_t size) return 1; } +#define NO_KERNEL_MAPPING_DUMMY 0x2222 static void *__alloc_from_contiguous(struct device *dev, size_t size, pgprot_t prot, struct page **ret_page, const void *caller, @@ -602,10 +603,20 @@ static void *__alloc_from_contiguous(struct device *dev, size_t size, __dma_clear_buffer(page, size, attrs); if (PageHighMem(page)) { - ptr = __dma_alloc_remap(page, size, GFP_KERNEL, prot, caller); - if (!ptr) { - dma_release_from_contiguous(dev, page, count); - return NULL; + if (!want_vaddr) { + /* + * Something non-NULL needs to be returned here. Give + * back a dummy address that is unmapped to catch + * clients trying to use the address incorrectly + */ + ptr = (void *)NO_KERNEL_MAPPING_DUMMY; + } else { + ptr = __dma_alloc_remap(page, size, GFP_KERNEL, prot, + caller); + if (!ptr) { + dma_release_from_contiguous(dev, page, count); + return NULL; + } } } else { __dma_remap(page, size, prot, want_vaddr); @@ -620,7 +631,7 @@ static void __free_from_contiguous(struct device *dev, struct page *page, void *cpu_addr, size_t size, bool want_vaddr) { if (PageHighMem(page)) - __dma_free_remap(cpu_addr, size); + __dma_free_remap(cpu_addr, size, true); else __dma_remap(page, size, PAGE_KERNEL, false); dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); @@ -651,7 +662,7 @@ static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot) #define __alloc_from_contiguous(dev, size, prot, ret, c, wv) NULL #define __free_from_pool(cpu_addr, size) 0 #define __free_from_contiguous(dev, page, cpu_addr, size, wv) do { } while (0) -#define __dma_free_remap(cpu_addr, size) do { } while (0) +#define __dma_free_remap(cpu_addr, size, w) do { } while (0) #endif /* CONFIG_MMU */ @@ -838,7 +849,7 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr, return; } else if (!dev_get_cma_area(dev)) { if (want_vaddr && !is_coherent) - __dma_free_remap(cpu_addr, size); + __dma_free_remap(cpu_addr, size, false); __dma_free_buffer(page, size); } else { /* -- 2.11.0