diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/dma/Kconfig | 12 | ||||
| -rw-r--r-- | kernel/dma/coherent.c | 13 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 105 | ||||
| -rw-r--r-- | kernel/dma/remap.c | 51 |
4 files changed, 115 insertions, 66 deletions
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig index 9decbba255fc..73c5c2b8e824 100644 --- a/kernel/dma/Kconfig +++ b/kernel/dma/Kconfig @@ -20,6 +20,15 @@ config ARCH_HAS_DMA_COHERENCE_H config ARCH_HAS_DMA_SET_MASK bool +# +# Select this option if the architecture needs special handling for +# DMA_ATTR_WRITE_COMBINE. Normally the "uncached" mapping should be what +# people thing of when saying write combine, so very few platforms should +# need to enable this. +# +config ARCH_HAS_DMA_WRITE_COMBINE + bool + config DMA_DECLARE_COHERENT bool @@ -45,9 +54,6 @@ config ARCH_HAS_DMA_PREP_COHERENT config ARCH_HAS_DMA_COHERENT_TO_PFN bool -config ARCH_HAS_DMA_MMAP_PGPROT - bool - config ARCH_HAS_FORCE_DMA_UNENCRYPTED bool diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c index 29fd6590dc1e..545e3869b0e3 100644 --- a/kernel/dma/coherent.c +++ b/kernel/dma/coherent.c @@ -122,18 +122,6 @@ int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, dma_release_coherent_memory(mem); return ret; } -EXPORT_SYMBOL(dma_declare_coherent_memory); - -void dma_release_declared_memory(struct device *dev) -{ - struct dma_coherent_mem *mem = dev->dma_mem; - - if (!mem) - return; - dma_release_coherent_memory(mem); - dev->dma_mem = NULL; -} -EXPORT_SYMBOL(dma_release_declared_memory); static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem, ssize_t size, dma_addr_t *dma_handle) @@ -288,7 +276,6 @@ int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma, return __dma_mmap_from_coherent(mem, vma, vaddr, size, ret); } -EXPORT_SYMBOL(dma_mmap_from_dev_coherent); int dma_mmap_from_global_coherent(struct vm_area_struct *vma, void *vaddr, size_t size, int *ret) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index b0038ca3aa92..64a3d294f4b4 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -136,17 +136,29 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, return ret; } +/* + * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems + * that the intention is to allow exporting memory allocated via the + * coherent DMA APIs through the dma_buf API, which only accepts a + * scattertable. This presents a couple of problems: + * 1. Not all memory allocated via the coherent DMA APIs is backed by + * a struct page + * 2. Passing coherent DMA memory into the streaming APIs is not allowed + * as we will try to flush the memory through a different alias to that + * actually being used (and the flushes are redundant.) + */ int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { const struct dma_map_ops *ops = get_dma_ops(dev); - if (!dma_is_direct(ops) && ops->get_sgtable) - return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, - attrs); - return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size, - attrs); + if (dma_is_direct(ops)) + return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, + size, attrs); + if (!ops->get_sgtable) + return -ENXIO; + return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, attrs); } EXPORT_SYMBOL(dma_get_sgtable_attrs); @@ -161,9 +173,11 @@ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) && (attrs & DMA_ATTR_NON_CONSISTENT))) return prot; - if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_MMAP_PGPROT)) - return arch_dma_mmap_pgprot(dev, prot, attrs); - return pgprot_noncached(prot); +#ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE + if (attrs & DMA_ATTR_WRITE_COMBINE) + return pgprot_writecombine(prot); +#endif + return pgprot_dmacoherent(prot); } #endif /* CONFIG_MMU */ @@ -174,7 +188,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { -#ifndef CONFIG_ARCH_NO_COHERENT_DMA_MMAP +#ifdef CONFIG_MMU unsigned long user_count = vma_pages(vma); unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned long off = vma->vm_pgoff; @@ -205,8 +219,29 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, user_count << PAGE_SHIFT, vma->vm_page_prot); #else return -ENXIO; -#endif /* !CONFIG_ARCH_NO_COHERENT_DMA_MMAP */ +#endif /* CONFIG_MMU */ +} + +/** + * dma_can_mmap - check if a given device supports dma_mmap_* + * @dev: device to check + * + * Returns %true if @dev supports dma_mmap_coherent() and dma_mmap_attrs() to + * map DMA allocations to userspace. + */ +bool dma_can_mmap(struct device *dev) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (dma_is_direct(ops)) { + return IS_ENABLED(CONFIG_MMU) && + (dev_is_dma_coherent(dev) || + IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN)); + } + + return ops->mmap != NULL; } +EXPORT_SYMBOL_GPL(dma_can_mmap); /** * dma_mmap_attrs - map a coherent DMA allocation into user space @@ -227,31 +262,15 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, { const struct dma_map_ops *ops = get_dma_ops(dev); - if (!dma_is_direct(ops) && ops->mmap) - return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs); - return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, attrs); + if (dma_is_direct(ops)) + return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size, + attrs); + if (!ops->mmap) + return -ENXIO; + return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs); } EXPORT_SYMBOL(dma_mmap_attrs); -static u64 dma_default_get_required_mask(struct device *dev) -{ - u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT); - u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT)); - u64 mask; - - if (!high_totalram) { - /* convert to mask just covering totalram */ - low_totalram = (1 << (fls(low_totalram) - 1)); - low_totalram += low_totalram - 1; - mask = low_totalram; - } else { - high_totalram = (1 << (fls(high_totalram) - 1)); - high_totalram += high_totalram - 1; - mask = (((u64)high_totalram) << 32) + 0xffffffff; - } - return mask; -} - u64 dma_get_required_mask(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); @@ -260,7 +279,16 @@ u64 dma_get_required_mask(struct device *dev) return dma_direct_get_required_mask(dev); if (ops->get_required_mask) return ops->get_required_mask(dev); - return dma_default_get_required_mask(dev); + + /* + * We require every DMA ops implementation to at least support a 32-bit + * DMA mask (and use bounce buffering if that isn't supported in + * hardware). As the direct mapping code has its own routine to + * actually report an optimal mask we default to 32-bit here as that + * is the right thing for most IOMMUs, and at least not actively + * harmful in general. + */ + return DMA_BIT_MASK(32); } EXPORT_SYMBOL_GPL(dma_get_required_mask); @@ -405,3 +433,14 @@ size_t dma_max_mapping_size(struct device *dev) return size; } EXPORT_SYMBOL_GPL(dma_max_mapping_size); + +unsigned long dma_get_merge_boundary(struct device *dev) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + if (!ops || !ops->get_merge_boundary) + return 0; /* can't merge */ + + return ops->get_merge_boundary(dev); +} +EXPORT_SYMBOL_GPL(dma_get_merge_boundary); diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c index ffe78f0b2fe4..ca4e5d44b571 100644 --- a/kernel/dma/remap.c +++ b/kernel/dma/remap.c @@ -11,13 +11,21 @@ #include <linux/slab.h> #include <linux/vmalloc.h> +struct page **dma_common_find_pages(void *cpu_addr) +{ + struct vm_struct *area = find_vm_area(cpu_addr); + + if (!area || area->flags != VM_DMA_COHERENT) + return NULL; + return area->pages; +} + static struct vm_struct *__dma_common_pages_remap(struct page **pages, - size_t size, unsigned long vm_flags, pgprot_t prot, - const void *caller) + size_t size, pgprot_t prot, const void *caller) { struct vm_struct *area; - area = get_vm_area_caller(size, vm_flags, caller); + area = get_vm_area_caller(size, VM_DMA_COHERENT, caller); if (!area) return NULL; @@ -34,12 +42,11 @@ static struct vm_struct *__dma_common_pages_remap(struct page **pages, * Cannot be used in non-sleeping contexts */ void *dma_common_pages_remap(struct page **pages, size_t size, - unsigned long vm_flags, pgprot_t prot, - const void *caller) + pgprot_t prot, const void *caller) { struct vm_struct *area; - area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller); + area = __dma_common_pages_remap(pages, size, prot, caller); if (!area) return NULL; @@ -53,7 +60,6 @@ void *dma_common_pages_remap(struct page **pages, size_t size, * Cannot be used in non-sleeping contexts */ void *dma_common_contiguous_remap(struct page *page, size_t size, - unsigned long vm_flags, pgprot_t prot, const void *caller) { int i; @@ -67,7 +73,7 @@ void *dma_common_contiguous_remap(struct page *page, size_t size, for (i = 0; i < (size >> PAGE_SHIFT); i++) pages[i] = nth_page(page, i); - area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller); + area = __dma_common_pages_remap(pages, size, prot, caller); kfree(pages); @@ -79,11 +85,11 @@ void *dma_common_contiguous_remap(struct page *page, size_t size, /* * Unmaps a range previously mapped by dma_common_*_remap */ -void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags) +void dma_common_free_remap(void *cpu_addr, size_t size) { - struct vm_struct *area = find_vm_area(cpu_addr); + struct page **pages = dma_common_find_pages(cpu_addr); - if (!area || (area->flags & vm_flags) != vm_flags) { + if (!pages) { WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr); return; } @@ -105,7 +111,16 @@ static int __init early_coherent_pool(char *p) } early_param("coherent_pool", early_coherent_pool); -int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) +static gfp_t dma_atomic_pool_gfp(void) +{ + if (IS_ENABLED(CONFIG_ZONE_DMA)) + return GFP_DMA; + if (IS_ENABLED(CONFIG_ZONE_DMA32)) + return GFP_DMA32; + return GFP_KERNEL; +} + +static int __init dma_atomic_pool_init(void) { unsigned int pool_size_order = get_order(atomic_pool_size); unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT; @@ -117,7 +132,7 @@ int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) page = dma_alloc_from_contiguous(NULL, nr_pages, pool_size_order, false); else - page = alloc_pages(gfp, pool_size_order); + page = alloc_pages(dma_atomic_pool_gfp(), pool_size_order); if (!page) goto out; @@ -127,8 +142,9 @@ int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) if (!atomic_pool) goto free_page; - addr = dma_common_contiguous_remap(page, atomic_pool_size, VM_USERMAP, - prot, __builtin_return_address(0)); + addr = dma_common_contiguous_remap(page, atomic_pool_size, + pgprot_dmacoherent(PAGE_KERNEL), + __builtin_return_address(0)); if (!addr) goto destroy_genpool; @@ -143,7 +159,7 @@ int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) return 0; remove_mapping: - dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP); + dma_common_free_remap(addr, atomic_pool_size); destroy_genpool: gen_pool_destroy(atomic_pool); atomic_pool = NULL; @@ -155,6 +171,7 @@ out: atomic_pool_size / 1024); return -ENOMEM; } +postcore_initcall(dma_atomic_pool_init); bool dma_in_atomic_pool(void *start, size_t size) { @@ -217,7 +234,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, arch_dma_prep_coherent(page, size); /* create a coherent mapping */ - ret = dma_common_contiguous_remap(page, size, VM_USERMAP, + ret = dma_common_contiguous_remap(page, size, dma_pgprot(dev, PAGE_KERNEL, attrs), __builtin_return_address(0)); if (!ret) { |