// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2018-2020 Christoph Hellwig. * * DMA operations that map physical memory directly without using an IOMMU. */ #include /* for max_pfn */ #include #include #include #include #include #include #include #include #include /* * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use it * it for entirely different regions. In that case the arch code needs to * override the variable below for dma-direct to work properly. */ unsigned int zone_dma_bits __ro_after_init = 24; static inline dma_addr_t phys_to_dma_direct(struct device *dev, phys_addr_t phys) { if (force_dma_unencrypted(dev)) return phys_to_dma_unencrypted(dev, phys); return phys_to_dma(dev, phys); } static inline struct page *dma_direct_to_page(struct device *dev, dma_addr_t dma_addr) { return pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_addr))); } u64 dma_direct_get_required_mask(struct device *dev) { phys_addr_t phys = (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT; u64 max_dma = phys_to_dma_direct(dev, phys); return (1ULL << (fls64(max_dma) - 1)) * 2 - 1; } static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask, u64 *phys_limit) { u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit); /* * Optimistically try the zone that the physical address mask falls * into first. If that returns memory that isn't actually addressable * we will fallback to the next lower zone and try again. * * Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding * zones. */ *phys_limit = dma_to_phys(dev, dma_limit); if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits)) return GFP_DMA; if (*phys_limit <= DMA_BIT_MASK(32)) return GFP_DMA32; return 0; } static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) { dma_addr_t dma_addr = phys_to_dma_direct(dev, phys); if (dma_addr == DMA_MAPPING_ERROR) return false; return dma_addr + size - 1 <= min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit); } /* * Decrypting memory is allowed to block, so if this device requires * unencrypted memory it must come from atomic pools. */ static inline bool dma_should_alloc_from_pool(struct device *dev, gfp_t gfp, unsigned long attrs) { if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)) return false; if (gfpflags_allow_blocking(gfp)) return false; if (force_dma_unencrypted(dev)) return true; if (!IS_ENABLED(CONFIG_DMA_DIRECT_REMAP)) return false; if (dma_alloc_need_uncached(dev, attrs)) return true; return false; } static inline bool dma_should_free_from_pool(struct device *dev, unsigned long attrs) { if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL)) return true; if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && !force_dma_unencrypted(dev)) return false; if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP)) return true; return false; } static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, gfp_t gfp) { int node = dev_to_node(dev); struct page *page = NULL; u64 phys_limit; WARN_ON_ONCE(!PAGE_ALIGNED(size)); gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, &phys_limit); page = dma_alloc_contiguous(dev, size, gfp); if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { dma_free_contiguous(dev, page, size); page = NULL; } again: if (!page) page = alloc_pages_node(node, gfp, get_order(size)); if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { dma_free_contiguous(dev, page, size); page = NULL; if (IS_ENABLED(CONFIG_ZONE_DMA32) && phys_limit < DMA_BIT_MASK(64) && !(gfp & (GFP_DMA32 | GFP_DMA))) { gfp |= GFP_DMA32; goto again; } if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) { gfp = (gfp & ~GFP_DMA32) | GFP_DMA; goto again; } } return page; } void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { struct page *page; void *ret; int err; if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && dma_alloc_need_uncached(dev, attrs)) return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); size = PAGE_ALIGN(size); if (attrs & DMA_ATTR_NO_WARN) gfp |= __GFP_NOWARN; if (dma_should_alloc_from_pool(dev, gfp, attrs)) { u64 phys_mask; gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, &phys_mask); page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok); if (!page) return NULL; goto done; } /* we always manually zero the memory once we are done */ page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO); if (!page) return NULL; if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && !force_dma_unencrypted(dev)) { /* remove any dirty cache lines on the kernel alias */ if (!PageHighMem(page)) arch_dma_prep_coherent(page, size); /* return the page pointer as the opaque cookie */ ret = page; goto done; } if ((IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && dma_alloc_need_uncached(dev, attrs)) || (IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) { /* remove any dirty cache lines on the kernel alias */ arch_dma_prep_coherent(page, size); /* create a coherent mapping */ ret = dma_common_contiguous_remap(page, size, dma_pgprot(dev, PAGE_KERNEL, attrs), __builtin_return_address(0)); if (!ret) goto out_free_pages; if (force_dma_unencrypted(dev)) { err = set_memory_decrypted((unsigned long)ret, 1 << get_order(size)); if (err) goto out_free_pages; } memset(ret, 0, size); goto done; } if (PageHighMem(page)) { /* * Depending on the cma= arguments and per-arch setup * dma_alloc_contiguous could return highmem pages. * Without remapping there is no way to return them here, * so log an error and fail. */ dev_info(dev, "Rejecting highmem page from CMA.\n"); goto out_free_pages; } ret = page_address(page); if (force_dma_unencrypted(dev)) { err = set_memory_decrypted((unsigned long)ret, 1 << get_order(size)); if (err) goto out_free_pages; } memset(ret, 0, size); if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && dma_alloc_need_uncached(dev, attrs)) { arch_dma_prep_coherent(page, size); ret = arch_dma_set_uncached(ret, size); if (IS_ERR(ret)) goto out_encrypt_pages; } done: *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); return ret; out_encrypt_pages: if (force_dma_unencrypted(dev)) { err = set_memory_encrypted((unsigned long)page_address(page), 1 << get_order(size)); /* If memory cannot be re-encrypted, it must be leaked */ if (err) return NULL; } out_free_pages: dma_free_contiguous(dev, page, size); return NULL; } void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { unsigned int page_order = get_order(size); if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && dma_alloc_need_uncached(dev, attrs)) { arch_dma_free(dev, size, cpu_addr, dma_addr, attrs); return; } /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ if (dma_should_free_from_pool(dev, attrs) && dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size))) return; if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && !force_dma_unencrypted(dev)) { /* cpu_addr is a struct page cookie, not a kernel address */ dma_free_contiguous(dev, cpu_addr, size); return; } if (force_dma_unencrypted(dev)) set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order); 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); } struct page *dma_direct_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp) { struct page *page; void *ret; if (dma_should_alloc_from_pool(dev, gfp, 0)) { page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok); if (!page) return NULL; goto done; } page = __dma_direct_alloc_pages(dev, size, gfp); if (!page) return NULL; ret = page_address(page); if (force_dma_unencrypted(dev)) { if (set_memory_decrypted((unsigned long)ret, 1 << get_order(size))) goto out_free_pages; } memset(ret, 0, size); done: *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); return page; out_free_pages: dma_free_contiguous(dev, page, size); return NULL; } void dma_direct_free_pages(struct device *dev, size_t size, struct page *page, dma_addr_t dma_addr, enum dma_data_direction dir) { unsigned int page_order = get_order(size); void *vaddr = page_address(page); /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */ if (dma_should_free_from_pool(dev, 0) && dma_free_from_pool(dev, vaddr, size)) return; if (force_dma_unencrypted(dev)) set_memory_encrypted((unsigned long)vaddr, 1 << page_order); dma_free_contiguous(dev, page, size); } #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ defined(CONFIG_SWIOTLB) void dma_direct_sync_sg_for_device(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir) { struct scatterlist *sg; int i; for_each_sg(sgl, sg, nents, i) { phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg)); if (unlikely(is_swiotlb_buffer(paddr))) swiotlb_tbl_sync_single(dev, paddr, sg->length, dir, SYNC_FOR_DEVICE); if (!dev_is_dma_coherent(dev)) arch_sync_dma_for_device(paddr, sg->length, dir); } } #endif #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \ defined(CONFIG_SWIOTLB) void dma_direct_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir) { struct scatterlist *sg; int i; for_each_sg(sgl, sg, nents, i) { phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg)); if (!dev_is_dma_coherent(dev)) arch_sync_dma_for_cpu(paddr, sg->length, dir); if (unlikely(is_swiotlb_buffer(paddr))) swiotlb_tbl_sync_single(dev, paddr, sg->length, dir, SYNC_FOR_CPU); if (dir == DMA_FROM_DEVICE) arch_dma_mark_clean(paddr, sg->length); } if (!dev_is_dma_coherent(dev)) arch_sync_dma_for_cpu_all(); } void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir, unsigned long attrs) { struct scatterlist *sg; int i; for_each_sg(sgl, sg, nents, i) dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir, attrs); } #endif int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir, unsigned long attrs) { int i; struct scatterlist *sg; for_each_sg(sgl, sg, nents, i) { sg->dma_address = dma_direct_map_page(dev, sg_page(sg), sg->offset, sg->length, dir, attrs); if (sg->dma_address == DMA_MAPPING_ERROR) goto out_unmap; sg_dma_len(sg) = sg->length; } return nents; out_unmap: dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC); return 0; } dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr, size_t size, enum dma_data_direction dir, unsigned long attrs) { dma_addr_t dma_addr = paddr; if (unlikely(!dma_capable(dev, dma_addr, size, false))) { dev_err_once(dev, "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); WARN_ON_ONCE(1); return DMA_MAPPING_ERROR; } return dma_addr; } int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { struct page *page = dma_direct_to_page(dev, dma_addr); int ret; ret = sg_alloc_table(sgt, 1, GFP_KERNEL); if (!ret) sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); return ret; } bool dma_direct_can_mmap(struct device *dev) { return dev_is_dma_coherent(dev) || IS_ENABLED(CONFIG_DMA_NONCOHERENT_MMAP); } int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) { unsigned long user_count = vma_pages(vma); unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr)); int ret = -ENXIO; vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) return ret; if (vma->vm_pgoff >= count || user_count > count - vma->vm_pgoff) return -ENXIO; return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff, user_count << PAGE_SHIFT, vma->vm_page_prot); } int dma_direct_supported(struct device *dev, u64 mask) { u64 min_mask = (max_pfn - 1) << PAGE_SHIFT; /* * Because 32-bit DMA masks are so common we expect every architecture * to be able to satisfy them - either by not supporting more physical * memory, or by providing a ZONE_DMA32. If neither is the case, the * architecture needs to use an IOMMU instead of the direct mapping. */ if (mask >= DMA_BIT_MASK(32)) return 1; /* * This check needs to be against the actual bit mask value, so use * phys_to_dma_unencrypted() here so that the SME encryption mask isn't * part of the check. */ if (IS_ENABLED(CONFIG_ZONE_DMA)) min_mask = min_t(u64, min_mask, DMA_BIT_MASK(zone_dma_bits)); return mask >= phys_to_dma_unencrypted(dev, min_mask); } size_t dma_direct_max_mapping_size(struct device *dev) { /* If SWIOTLB is active, use its maximum mapping size */ if (is_swiotlb_active() && (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE)) return swiotlb_max_mapping_size(dev); return SIZE_MAX; } bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr) { return !dev_is_dma_coherent(dev) || is_swiotlb_buffer(dma_to_phys(dev, dma_addr)); } /** * dma_direct_set_offset - Assign scalar offset for a single DMA range. * @dev: device pointer; needed to "own" the alloced memory. * @cpu_start: beginning of memory region covered by this offset. * @dma_start: beginning of DMA/PCI region covered by this offset. * @size: size of the region. * * This is for the simple case of a uniform offset which cannot * be discovered by "dma-ranges". * * It returns -ENOMEM if out of memory, -EINVAL if a map * already exists, 0 otherwise. * * Note: any call to this from a driver is a bug. The mapping needs * to be described by the device tree or other firmware interfaces. */ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start, dma_addr_t dma_start, u64 size) { struct bus_dma_region *map; u64 offset = (u64)cpu_start - (u64)dma_start; if (dev->dma_range_map) { dev_err(dev, "attempt to add DMA range to existing map\n"); return -EINVAL; } if (!offset) return 0; map = kcalloc(2, sizeof(*map), GFP_KERNEL); if (!map) return -ENOMEM; map[0].cpu_start = cpu_start; map[0].dma_start = dma_start; map[0].offset = offset; map[0].size = size; dev->dma_range_map = map; return 0; } EXPORT_SYMBOL_GPL(dma_direct_set_offset);