// SPDX-License-Identifier: GPL-2.0-only /* * A fairly generic DMA-API to IOMMU-API glue layer. * * Copyright (C) 2014-2015 ARM Ltd. * * based in part on arch/arm/mm/dma-mapping.c: * Copyright (C) 2000-2004 Russell King */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct iommu_dma_msi_page { struct list_head list; dma_addr_t iova; phys_addr_t phys; }; enum iommu_dma_cookie_type { IOMMU_DMA_IOVA_COOKIE, IOMMU_DMA_MSI_COOKIE, }; struct iommu_dma_cookie { enum iommu_dma_cookie_type type; union { /* Full allocator for IOMMU_DMA_IOVA_COOKIE */ struct iova_domain iovad; /* Trivial linear page allocator for IOMMU_DMA_MSI_COOKIE */ dma_addr_t msi_iova; }; struct list_head msi_page_list; spinlock_t msi_lock; /* Domain for flush queue callback; NULL if flush queue not in use */ struct iommu_domain *fq_domain; }; static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) { if (cookie->type == IOMMU_DMA_IOVA_COOKIE) return cookie->iovad.granule; return PAGE_SIZE; } static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type) { struct iommu_dma_cookie *cookie; cookie = kzalloc(sizeof(*cookie), GFP_KERNEL); if (cookie) { spin_lock_init(&cookie->msi_lock); INIT_LIST_HEAD(&cookie->msi_page_list); cookie->type = type; } return cookie; } /** * iommu_get_dma_cookie - Acquire DMA-API resources for a domain * @domain: IOMMU domain to prepare for DMA-API usage * * IOMMU drivers should normally call this from their domain_alloc * callback when domain->type == IOMMU_DOMAIN_DMA. */ int iommu_get_dma_cookie(struct iommu_domain *domain) { if (domain->iova_cookie) return -EEXIST; domain->iova_cookie = cookie_alloc(IOMMU_DMA_IOVA_COOKIE); if (!domain->iova_cookie) return -ENOMEM; return 0; } EXPORT_SYMBOL(iommu_get_dma_cookie); /** * iommu_get_msi_cookie - Acquire just MSI remapping resources * @domain: IOMMU domain to prepare * @base: Start address of IOVA region for MSI mappings * * Users who manage their own IOVA allocation and do not want DMA API support, * but would still like to take advantage of automatic MSI remapping, can use * this to initialise their own domain appropriately. Users should reserve a * contiguous IOVA region, starting at @base, large enough to accommodate the * number of PAGE_SIZE mappings necessary to cover every MSI doorbell address * used by the devices attached to @domain. */ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base) { struct iommu_dma_cookie *cookie; if (domain->type != IOMMU_DOMAIN_UNMANAGED) return -EINVAL; if (domain->iova_cookie) return -EEXIST; cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE); if (!cookie) return -ENOMEM; cookie->msi_iova = base; domain->iova_cookie = cookie; return 0; } EXPORT_SYMBOL(iommu_get_msi_cookie); /** * iommu_put_dma_cookie - Release a domain's DMA mapping resources * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() or * iommu_get_msi_cookie() * * IOMMU drivers should normally call this from their domain_free callback. */ void iommu_put_dma_cookie(struct iommu_domain *domain) { struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iommu_dma_msi_page *msi, *tmp; if (!cookie) return; if (cookie->type == IOMMU_DMA_IOVA_COOKIE && cookie->iovad.granule) put_iova_domain(&cookie->iovad); list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) { list_del(&msi->list); kfree(msi); } kfree(cookie); domain->iova_cookie = NULL; } EXPORT_SYMBOL(iommu_put_dma_cookie); /** * iommu_dma_get_resv_regions - Reserved region driver helper * @dev: Device from iommu_get_resv_regions() * @list: Reserved region list from iommu_get_resv_regions() * * IOMMU drivers can use this to implement their .get_resv_regions callback * for general non-IOMMU-specific reservations. Currently, this covers GICv3 * ITS region reservation on ACPI based ARM platforms that may require HW MSI * reservation. */ void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list) { if (!is_of_node(dev_iommu_fwspec_get(dev)->iommu_fwnode)) iort_iommu_msi_get_resv_regions(dev, list); } EXPORT_SYMBOL(iommu_dma_get_resv_regions); static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, phys_addr_t start, phys_addr_t end) { struct iova_domain *iovad = &cookie->iovad; struct iommu_dma_msi_page *msi_page; int i, num_pages; start -= iova_offset(iovad, start); num_pages = iova_align(iovad, end - start) >> iova_shift(iovad); msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL); if (!msi_page) return -ENOMEM; for (i = 0; i < num_pages; i++) { msi_page[i].phys = start; msi_page[i].iova = start; INIT_LIST_HEAD(&msi_page[i].list); list_add(&msi_page[i].list, &cookie->msi_page_list); start += iovad->granule; } return 0; } static int iova_reserve_pci_windows(struct pci_dev *dev, struct iova_domain *iovad) { struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus); struct resource_entry *window; unsigned long lo, hi; phys_addr_t start = 0, end; resource_list_for_each_entry(window, &bridge->windows) { if (resource_type(window->res) != IORESOURCE_MEM) continue; lo = iova_pfn(iovad, window->res->start - window->offset); hi = iova_pfn(iovad, window->res->end - window->offset); reserve_iova(iovad, lo, hi); } /* Get reserved DMA windows from host bridge */ resource_list_for_each_entry(window, &bridge->dma_ranges) { end = window->res->start - window->offset; resv_iova: if (end > start) { lo = iova_pfn(iovad, start); hi = iova_pfn(iovad, end); reserve_iova(iovad, lo, hi); } else { /* dma_ranges list should be sorted */ dev_err(&dev->dev, "Failed to reserve IOVA\n"); return -EINVAL; } start = window->res->end - window->offset + 1; /* If window is last entry */ if (window->node.next == &bridge->dma_ranges && end != ~(phys_addr_t)0) { end = ~(phys_addr_t)0; goto resv_iova; } } return 0; } static int iova_reserve_iommu_regions(struct device *dev, struct iommu_domain *domain) { struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; struct iommu_resv_region *region; LIST_HEAD(resv_regions); int ret = 0; if (dev_is_pci(dev)) { ret = iova_reserve_pci_windows(to_pci_dev(dev), iovad); if (ret) return ret; } iommu_get_resv_regions(dev, &resv_regions); list_for_each_entry(region, &resv_regions, list) { unsigned long lo, hi; /* We ARE the software that manages these! */ if (region->type == IOMMU_RESV_SW_MSI) continue; lo = iova_pfn(iovad, region->start); hi = iova_pfn(iovad, region->start + region->length - 1); reserve_iova(iovad, lo, hi); if (region->type == IOMMU_RESV_MSI) ret = cookie_init_hw_msi_region(cookie, region->start, region->start + region->length); if (ret) break; } iommu_put_resv_regions(dev, &resv_regions); return ret; } static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad) { struct iommu_dma_cookie *cookie; struct iommu_domain *domain; cookie = container_of(iovad, struct iommu_dma_cookie, iovad); domain = cookie->fq_domain; /* * The IOMMU driver supporting DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE * implies that ops->flush_iotlb_all must be non-NULL. */ domain->ops->flush_iotlb_all(domain); } /** * iommu_dma_init_domain - Initialise a DMA mapping domain * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() * @base: IOVA at which the mappable address space starts * @size: Size of IOVA space * @dev: Device the domain is being initialised for * * @base and @size should be exact multiples of IOMMU page granularity to * avoid rounding surprises. If necessary, we reserve the page at address 0 * to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but * any change which could make prior IOVAs invalid will fail. */ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size, struct device *dev) { struct iommu_dma_cookie *cookie = domain->iova_cookie; unsigned long order, base_pfn; struct iova_domain *iovad; int attr; if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE) return -EINVAL; iovad = &cookie->iovad; /* Use the smallest supported page size for IOVA granularity */ order = __ffs(domain->pgsize_bitmap); base_pfn = max_t(unsigned long, 1, base >> order); /* Check the domain allows at least some access to the device... */ if (domain->geometry.force_aperture) { if (base > domain->geometry.aperture_end || base + size <= domain->geometry.aperture_start) { pr_warn("specified DMA range outside IOMMU capability\n"); return -EFAULT; } /* ...then finally give it a kicking to make sure it fits */ base_pfn = max_t(unsigned long, base_pfn, domain->geometry.aperture_start >> order); } /* start_pfn is always nonzero for an already-initialised domain */ if (iovad->start_pfn) { if (1UL << order != iovad->granule || base_pfn != iovad->start_pfn) { pr_warn("Incompatible range for DMA domain\n"); return -EFAULT; } return 0; } init_iova_domain(iovad, 1UL << order, base_pfn); if (!cookie->fq_domain && !iommu_domain_get_attr(domain, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) { cookie->fq_domain = domain; init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL); } if (!dev) return 0; return iova_reserve_iommu_regions(dev, domain); } static int iommu_dma_deferred_attach(struct device *dev, struct iommu_domain *domain) { const struct iommu_ops *ops = domain->ops; if (!is_kdump_kernel()) return 0; if (unlikely(ops->is_attach_deferred && ops->is_attach_deferred(domain, dev))) return iommu_attach_device(domain, dev); return 0; } /** * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API * page flags. * @dir: Direction of DMA transfer * @coherent: Is the DMA master cache-coherent? * @attrs: DMA attributes for the mapping * * Return: corresponding IOMMU API page protection flags */ static int dma_info_to_prot(enum dma_data_direction dir, bool coherent, unsigned long attrs) { int prot = coherent ? IOMMU_CACHE : 0; if (attrs & DMA_ATTR_PRIVILEGED) prot |= IOMMU_PRIV; switch (dir) { case DMA_BIDIRECTIONAL: return prot | IOMMU_READ | IOMMU_WRITE; case DMA_TO_DEVICE: return prot | IOMMU_READ; case DMA_FROM_DEVICE: return prot | IOMMU_WRITE; default: return 0; } } static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, size_t size, u64 dma_limit, struct device *dev) { struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; unsigned long shift, iova_len, iova = 0; if (cookie->type == IOMMU_DMA_MSI_COOKIE) { cookie->msi_iova += size; return cookie->msi_iova - size; } shift = iova_shift(iovad); iova_len = size >> shift; /* * Freeing non-power-of-two-sized allocations back into the IOVA caches * will come back to bite us badly, so we have to waste a bit of space * rounding up anything cacheable to make sure that can't happen. The * order of the unadjusted size will still match upon freeing. */ if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1))) iova_len = roundup_pow_of_two(iova_len); dma_limit = min_not_zero(dma_limit, dev->bus_dma_limit); if (domain->geometry.force_aperture) dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end); /* Try to get PCI devices a SAC address */ if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) iova = alloc_iova_fast(iovad, iova_len, DMA_BIT_MASK(32) >> shift, false); if (!iova) iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift, true); return (dma_addr_t)iova << shift; } static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie, dma_addr_t iova, size_t size) { struct iova_domain *iovad = &cookie->iovad; /* The MSI case is only ever cleaning up its most recent allocation */ if (cookie->type == IOMMU_DMA_MSI_COOKIE) cookie->msi_iova -= size; else if (cookie->fq_domain) /* non-strict mode */ queue_iova(iovad, iova_pfn(iovad, iova), size >> iova_shift(iovad), 0); else free_iova_fast(iovad, iova_pfn(iovad, iova), size >> iova_shift(iovad)); } static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr, size_t size) { struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; size_t iova_off = iova_offset(iovad, dma_addr); struct iommu_iotlb_gather iotlb_gather; size_t unmapped; dma_addr -= iova_off; size = iova_align(iovad, size + iova_off); iommu_iotlb_gather_init(&iotlb_gather); unmapped = iommu_unmap_fast(domain, dma_addr, size, &iotlb_gather); WARN_ON(unmapped != size); if (!cookie->fq_domain) iommu_tlb_sync(domain, &iotlb_gather); iommu_dma_free_iova(cookie, dma_addr, size); } static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, size_t size, int prot, u64 dma_mask) { struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; size_t iova_off = iova_offset(iovad, phys); dma_addr_t iova; if (unlikely(iommu_dma_deferred_attach(dev, domain))) return DMA_MAPPING_ERROR; size = iova_align(iovad, size + iova_off); iova = iommu_dma_alloc_iova(domain, size, dma_mask, dev); if (!iova) return DMA_MAPPING_ERROR; if (iommu_map_atomic(domain, iova, phys - iova_off, size, prot)) { iommu_dma_free_iova(cookie, iova, size); return DMA_MAPPING_ERROR; } return iova + iova_off; } static void __iommu_dma_free_pages(struct page **pages, int count) { while (count--) __free_page(pages[count]); kvfree(pages); } static struct page **__iommu_dma_alloc_pages(struct device *dev, unsigned int count, unsigned long order_mask, gfp_t gfp) { struct page **pages; unsigned int i = 0, nid = dev_to_node(dev); order_mask &= (2U << MAX_ORDER) - 1; if (!order_mask) return NULL; pages = kvzalloc(count * sizeof(*pages), GFP_KERNEL); if (!pages) return NULL; /* IOMMU can map any pages, so himem can also be used here */ gfp |= __GFP_NOWARN | __GFP_HIGHMEM; while (count) { struct page *page = NULL; unsigned int order_size; /* * Higher-order allocations are a convenience rather * than a necessity, hence using __GFP_NORETRY until * falling back to minimum-order allocations. */ for (order_mask &= (2U << __fls(count)) - 1; order_mask; order_mask &= ~order_size) { unsigned int order = __fls(order_mask); gfp_t alloc_flags = gfp; order_size = 1U << order; if (order_mask > order_size) alloc_flags |= __GFP_NORETRY; page = alloc_pages_node(nid, alloc_flags, order); if (!page) continue; if (!order) break; if (!PageCompound(page)) { split_page(page, order); break; } else if (!split_huge_page(page)) { break; } __free_pages(page, order); } if (!page) { __iommu_dma_free_pages(pages, i); return NULL; } count -= order_size; while (order_size--) pages[i++] = page++; } return pages; } /** * iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space * @dev: Device to allocate memory for. Must be a real device * attached to an iommu_dma_domain * @size: Size of buffer in bytes * @dma_handle: Out argument for allocated DMA handle * @gfp: Allocation flags * @attrs: DMA attributes for this allocation * * If @size is less than PAGE_SIZE, then a full CPU page will be allocated, * but an IOMMU which supports smaller pages might not map the whole thing. * * Return: Mapped virtual address, or NULL on failure. */ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; bool coherent = dev_is_dma_coherent(dev); int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap; struct page **pages; struct sg_table sgt; dma_addr_t iova; void *vaddr; *dma_handle = DMA_MAPPING_ERROR; if (unlikely(iommu_dma_deferred_attach(dev, domain))) return NULL; min_size = alloc_sizes & -alloc_sizes; if (min_size < PAGE_SIZE) { min_size = PAGE_SIZE; alloc_sizes |= PAGE_SIZE; } else { size = ALIGN(size, min_size); } if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES) alloc_sizes = min_size; count = PAGE_ALIGN(size) >> PAGE_SHIFT; pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT, gfp); if (!pages) return NULL; size = iova_align(iovad, size); iova = iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev); if (!iova) goto out_free_pages; if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL)) goto out_free_iova; if (!(ioprot & IOMMU_CACHE)) { struct scatterlist *sg; int i; for_each_sg(sgt.sgl, sg, sgt.orig_nents, i) arch_dma_prep_coherent(sg_page(sg), sg->length); } if (iommu_map_sg_atomic(domain, iova, sgt.sgl, sgt.orig_nents, ioprot) < size) goto out_free_sg; vaddr = dma_common_pages_remap(pages, size, prot, __builtin_return_address(0)); if (!vaddr) goto out_unmap; *dma_handle = iova; sg_free_table(&sgt); return vaddr; out_unmap: __iommu_dma_unmap(dev, iova, size); out_free_sg: sg_free_table(&sgt); out_free_iova: iommu_dma_free_iova(cookie, iova, size); out_free_pages: __iommu_dma_free_pages(pages, count); return NULL; } /** * __iommu_dma_mmap - Map a buffer into provided user VMA * @pages: Array representing buffer from __iommu_dma_alloc() * @size: Size of buffer in bytes * @vma: VMA describing requested userspace mapping * * Maps the pages of the buffer in @pages into @vma. The caller is responsible * for verifying the correct size and protection of @vma beforehand. */ static int __iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma) { return vm_map_pages(vma, pages, PAGE_ALIGN(size) >> PAGE_SHIFT); } static void iommu_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) { phys_addr_t phys; if (dev_is_dma_coherent(dev)) return; phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle); arch_sync_dma_for_cpu(phys, size, dir); } static void iommu_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction dir) { phys_addr_t phys; if (dev_is_dma_coherent(dev)) return; phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle); arch_sync_dma_for_device(phys, size, dir); } static void iommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl, int nelems, enum dma_data_direction dir) { struct scatterlist *sg; int i; if (dev_is_dma_coherent(dev)) return; for_each_sg(sgl, sg, nelems, i) arch_sync_dma_for_cpu(sg_phys(sg), sg->length, dir); } static void iommu_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sgl, int nelems, enum dma_data_direction dir) { struct scatterlist *sg; int i; if (dev_is_dma_coherent(dev)) return; for_each_sg(sgl, sg, nelems, i) arch_sync_dma_for_device(sg_phys(sg), sg->length, dir); } static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long attrs) { phys_addr_t phys = page_to_phys(page) + offset; bool coherent = dev_is_dma_coherent(dev); int prot = dma_info_to_prot(dir, coherent, attrs); dma_addr_t dma_handle; dma_handle = __iommu_dma_map(dev, phys, size, prot, dma_get_mask(dev)); if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && dma_handle != DMA_MAPPING_ERROR) arch_sync_dma_for_device(phys, size, dir); return dma_handle; } static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction dir, unsigned long attrs) { if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir); __iommu_dma_unmap(dev, dma_handle, size); } /* * Prepare a successfully-mapped scatterlist to give back to the caller. * * At this point the segments are already laid out by iommu_dma_map_sg() to * avoid individually crossing any boundaries, so we merely need to check a * segment's start address to avoid concatenating across one. */ static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, dma_addr_t dma_addr) { struct scatterlist *s, *cur = sg; unsigned long seg_mask = dma_get_seg_boundary(dev); unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev); int i, count = 0; for_each_sg(sg, s, nents, i) { /* Restore this segment's original unaligned fields first */ unsigned int s_iova_off = sg_dma_address(s); unsigned int s_length = sg_dma_len(s); unsigned int s_iova_len = s->length; s->offset += s_iova_off; s->length = s_length; sg_dma_address(s) = DMA_MAPPING_ERROR; sg_dma_len(s) = 0; /* * Now fill in the real DMA data. If... * - there is a valid output segment to append to * - and this segment starts on an IOVA page boundary * - but doesn't fall at a segment boundary * - and wouldn't make the resulting output segment too long */ if (cur_len && !s_iova_off && (dma_addr & seg_mask) && (max_len - cur_len >= s_length)) { /* ...then concatenate it with the previous one */ cur_len += s_length; } else { /* Otherwise start the next output segment */ if (i > 0) cur = sg_next(cur); cur_len = s_length; count++; sg_dma_address(cur) = dma_addr + s_iova_off; } sg_dma_len(cur) = cur_len; dma_addr += s_iova_len; if (s_length + s_iova_off < s_iova_len) cur_len = 0; } return count; } /* * If mapping failed, then just restore the original list, * but making sure the DMA fields are invalidated. */ static void __invalidate_sg(struct scatterlist *sg, int nents) { struct scatterlist *s; int i; for_each_sg(sg, s, nents, i) { if (sg_dma_address(s) != DMA_MAPPING_ERROR) s->offset += sg_dma_address(s); if (sg_dma_len(s)) s->length = sg_dma_len(s); sg_dma_address(s) = DMA_MAPPING_ERROR; sg_dma_len(s) = 0; } } /* * The DMA API client is passing in a scatterlist which could describe * any old buffer layout, but the IOMMU API requires everything to be * aligned to IOMMU pages. Hence the need for this complicated bit of * impedance-matching, to be able to hand off a suitably-aligned list, * but still preserve the original offsets and sizes for the caller. */ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs) { struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; struct scatterlist *s, *prev = NULL; int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs); dma_addr_t iova; size_t iova_len = 0; unsigned long mask = dma_get_seg_boundary(dev); int i; if (unlikely(iommu_dma_deferred_attach(dev, domain))) return 0; if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) iommu_dma_sync_sg_for_device(dev, sg, nents, dir); /* * Work out how much IOVA space we need, and align the segments to * IOVA granules for the IOMMU driver to handle. With some clever * trickery we can modify the list in-place, but reversibly, by * stashing the unaligned parts in the as-yet-unused DMA fields. */ for_each_sg(sg, s, nents, i) { size_t s_iova_off = iova_offset(iovad, s->offset); size_t s_length = s->length; size_t pad_len = (mask - iova_len + 1) & mask; sg_dma_address(s) = s_iova_off; sg_dma_len(s) = s_length; s->offset -= s_iova_off; s_length = iova_align(iovad, s_length + s_iova_off); s->length = s_length; /* * Due to the alignment of our single IOVA allocation, we can * depend on these assumptions about the segment boundary mask: * - If mask size >= IOVA size, then the IOVA range cannot * possibly fall across a boundary, so we don't care. * - If mask size < IOVA size, then the IOVA range must start * exactly on a boundary, therefore we can lay things out * based purely on segment lengths without needing to know * the actual addresses beforehand. * - The mask must be a power of 2, so pad_len == 0 if * iova_len == 0, thus we cannot dereference prev the first * time through here (i.e. before it has a meaningful value). */ if (pad_len && pad_len < s_length - 1) { prev->length += pad_len; iova_len += pad_len; } iova_len += s_length; prev = s; } iova = iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), dev); if (!iova) goto out_restore_sg; /* * We'll leave any physical concatenation to the IOMMU driver's * implementation - it knows better than we do. */ if (iommu_map_sg_atomic(domain, iova, sg, nents, prot) < iova_len) goto out_free_iova; return __finalise_sg(dev, sg, nents, iova); out_free_iova: iommu_dma_free_iova(cookie, iova, iova_len); out_restore_sg: __invalidate_sg(sg, nents); return 0; } static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs) { dma_addr_t start, end; struct scatterlist *tmp; int i; if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir); /* * The scatterlist segments are mapped into a single * contiguous IOVA allocation, so this is incredibly easy. */ start = sg_dma_address(sg); for_each_sg(sg_next(sg), tmp, nents - 1, i) { if (sg_dma_len(tmp) == 0) break; sg = tmp; } end = sg_dma_address(sg) + sg_dma_len(sg); __iommu_dma_unmap(dev, start, end - start); } static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys, size_t size, enum dma_data_direction dir, unsigned long attrs) { return __iommu_dma_map(dev, phys, size, dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO, dma_get_mask(dev)); } static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir, unsigned long attrs) { __iommu_dma_unmap(dev, handle, size); } static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr) { size_t alloc_size = PAGE_ALIGN(size); int count = alloc_size >> PAGE_SHIFT; struct page *page = NULL, **pages = NULL; /* Non-coherent atomic allocation? Easy */ if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && dma_free_from_pool(cpu_addr, alloc_size)) return; if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { /* * If it the address is remapped, then it's either non-coherent * or highmem CMA, or an iommu_dma_alloc_remap() construction. */ pages = dma_common_find_pages(cpu_addr); if (!pages) page = vmalloc_to_page(cpu_addr); dma_common_free_remap(cpu_addr, alloc_size); } else { /* Lowmem means a coherent atomic or CMA allocation */ page = virt_to_page(cpu_addr); } if (pages) __iommu_dma_free_pages(pages, count); if (page) dma_free_contiguous(dev, page, alloc_size); } static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle, unsigned long attrs) { __iommu_dma_unmap(dev, handle, size); __iommu_dma_free(dev, size, cpu_addr); } static void *iommu_dma_alloc_pages(struct device *dev, size_t size, struct page **pagep, gfp_t gfp, unsigned long attrs) { bool coherent = dev_is_dma_coherent(dev); size_t alloc_size = PAGE_ALIGN(size); int node = dev_to_node(dev); struct page *page = NULL; void *cpu_addr; page = dma_alloc_contiguous(dev, alloc_size, gfp); if (!page) page = alloc_pages_node(node, gfp, get_order(alloc_size)); if (!page) return NULL; if (IS_ENABLED(CONFIG_DMA_REMAP) && (!coherent || PageHighMem(page))) { pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs); cpu_addr = dma_common_contiguous_remap(page, alloc_size, prot, __builtin_return_address(0)); if (!cpu_addr) goto out_free_pages; if (!coherent) arch_dma_prep_coherent(page, size); } else { cpu_addr = page_address(page); } *pagep = page; memset(cpu_addr, 0, alloc_size); return cpu_addr; out_free_pages: dma_free_contiguous(dev, page, alloc_size); return NULL; } static void *iommu_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, unsigned long attrs) { bool coherent = dev_is_dma_coherent(dev); int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs); struct page *page = NULL; void *cpu_addr; gfp |= __GFP_ZERO; if (IS_ENABLED(CONFIG_DMA_REMAP) && gfpflags_allow_blocking(gfp) && !(attrs & DMA_ATTR_FORCE_CONTIGUOUS)) return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs); if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !gfpflags_allow_blocking(gfp) && !coherent) cpu_addr = dma_alloc_from_pool(PAGE_ALIGN(size), &page, gfp); else cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs); if (!cpu_addr) return NULL; *handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot, dev->coherent_dma_mask); if (*handle == DMA_MAPPING_ERROR) { __iommu_dma_free(dev, size, cpu_addr); return NULL; } return cpu_addr; } static int iommu_dma_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 nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned long pfn, off = vma->vm_pgoff; int ret; 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 (off >= nr_pages || vma_pages(vma) > nr_pages - off) return -ENXIO; if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { struct page **pages = dma_common_find_pages(cpu_addr); if (pages) return __iommu_dma_mmap(pages, size, vma); pfn = vmalloc_to_pfn(cpu_addr); } else { pfn = page_to_pfn(virt_to_page(cpu_addr)); } return remap_pfn_range(vma, vma->vm_start, pfn + off, vma->vm_end - vma->vm_start, vma->vm_page_prot); } static int iommu_dma_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; int ret; if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) { struct page **pages = dma_common_find_pages(cpu_addr); if (pages) { return sg_alloc_table_from_pages(sgt, pages, PAGE_ALIGN(size) >> PAGE_SHIFT, 0, size, GFP_KERNEL); } page = vmalloc_to_page(cpu_addr); } else { page = virt_to_page(cpu_addr); } ret = sg_alloc_table(sgt, 1, GFP_KERNEL); if (!ret) sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); return ret; } static unsigned long iommu_dma_get_merge_boundary(struct device *dev) { struct iommu_domain *domain = iommu_get_dma_domain(dev); return (1UL << __ffs(domain->pgsize_bitmap)) - 1; } static const struct dma_map_ops iommu_dma_ops = { .alloc = iommu_dma_alloc, .free = iommu_dma_free, .mmap = iommu_dma_mmap, .get_sgtable = iommu_dma_get_sgtable, .map_page = iommu_dma_map_page, .unmap_page = iommu_dma_unmap_page, .map_sg = iommu_dma_map_sg, .unmap_sg = iommu_dma_unmap_sg, .sync_single_for_cpu = iommu_dma_sync_single_for_cpu, .sync_single_for_device = iommu_dma_sync_single_for_device, .sync_sg_for_cpu = iommu_dma_sync_sg_for_cpu, .sync_sg_for_device = iommu_dma_sync_sg_for_device, .map_resource = iommu_dma_map_resource, .unmap_resource = iommu_dma_unmap_resource, .get_merge_boundary = iommu_dma_get_merge_boundary, }; /* * The IOMMU core code allocates the default DMA domain, which the underlying * IOMMU driver needs to support via the dma-iommu layer. */ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size) { struct iommu_domain *domain = iommu_get_domain_for_dev(dev); if (!domain) goto out_err; /* * The IOMMU core code allocates the default DMA domain, which the * underlying IOMMU driver needs to support via the dma-iommu layer. */ if (domain->type == IOMMU_DOMAIN_DMA) { if (iommu_dma_init_domain(domain, dma_base, size, dev)) goto out_err; dev->dma_ops = &iommu_dma_ops; } return; out_err: pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", dev_name(dev)); } static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, phys_addr_t msi_addr, struct iommu_domain *domain) { struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iommu_dma_msi_page *msi_page; dma_addr_t iova; int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; size_t size = cookie_msi_granule(cookie); msi_addr &= ~(phys_addr_t)(size - 1); list_for_each_entry(msi_page, &cookie->msi_page_list, list) if (msi_page->phys == msi_addr) return msi_page; msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC); if (!msi_page) return NULL; iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev); if (!iova) goto out_free_page; if (iommu_map(domain, iova, msi_addr, size, prot)) goto out_free_iova; INIT_LIST_HEAD(&msi_page->list); msi_page->phys = msi_addr; msi_page->iova = iova; list_add(&msi_page->list, &cookie->msi_page_list); return msi_page; out_free_iova: iommu_dma_free_iova(cookie, iova, size); out_free_page: kfree(msi_page); return NULL; } int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) { struct device *dev = msi_desc_to_dev(desc); struct iommu_domain *domain = iommu_get_domain_for_dev(dev); struct iommu_dma_cookie *cookie; struct iommu_dma_msi_page *msi_page; unsigned long flags; if (!domain || !domain->iova_cookie) { desc->iommu_cookie = NULL; return 0; } cookie = domain->iova_cookie; /* * We disable IRQs to rule out a possible inversion against * irq_desc_lock if, say, someone tries to retarget the affinity * of an MSI from within an IPI handler. */ spin_lock_irqsave(&cookie->msi_lock, flags); msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain); spin_unlock_irqrestore(&cookie->msi_lock, flags); msi_desc_set_iommu_cookie(desc, msi_page); if (!msi_page) return -ENOMEM; return 0; } void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg) { struct device *dev = msi_desc_to_dev(desc); const struct iommu_domain *domain = iommu_get_domain_for_dev(dev); const struct iommu_dma_msi_page *msi_page; msi_page = msi_desc_get_iommu_cookie(desc); if (!domain || !domain->iova_cookie || WARN_ON(!msi_page)) return; msg->address_hi = upper_32_bits(msi_page->iova); msg->address_lo &= cookie_msi_granule(domain->iova_cookie) - 1; msg->address_lo += lower_32_bits(msi_page->iova); } static int iommu_dma_init(void) { return iova_cache_get(); } arch_initcall(iommu_dma_init);