| /* |
| * Copyright(c) 2015 Intel Corporation. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of version 2 of the GNU General Public License as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| */ |
| #include <linux/radix-tree.h> |
| #include <linux/memremap.h> |
| #include <linux/device.h> |
| #include <linux/types.h> |
| #include <linux/pfn_t.h> |
| #include <linux/io.h> |
| #include <linux/mm.h> |
| #include <linux/memory_hotplug.h> |
| |
| #ifndef ioremap_cache |
| /* temporary while we convert existing ioremap_cache users to memremap */ |
| __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size) |
| { |
| return ioremap(offset, size); |
| } |
| #endif |
| |
| static void *try_ram_remap(resource_size_t offset, size_t size) |
| { |
| struct page *page = pfn_to_page(offset >> PAGE_SHIFT); |
| |
| /* In the simple case just return the existing linear address */ |
| if (!PageHighMem(page)) |
| return __va(offset); |
| return NULL; /* fallback to ioremap_cache */ |
| } |
| |
| /** |
| * memremap() - remap an iomem_resource as cacheable memory |
| * @offset: iomem resource start address |
| * @size: size of remap |
| * @flags: either MEMREMAP_WB or MEMREMAP_WT |
| * |
| * memremap() is "ioremap" for cases where it is known that the resource |
| * being mapped does not have i/o side effects and the __iomem |
| * annotation is not applicable. |
| * |
| * MEMREMAP_WB - matches the default mapping for "System RAM" on |
| * the architecture. This is usually a read-allocate write-back cache. |
| * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM |
| * memremap() will bypass establishing a new mapping and instead return |
| * a pointer into the direct map. |
| * |
| * MEMREMAP_WT - establish a mapping whereby writes either bypass the |
| * cache or are written through to memory and never exist in a |
| * cache-dirty state with respect to program visibility. Attempts to |
| * map "System RAM" with this mapping type will fail. |
| */ |
| void *memremap(resource_size_t offset, size_t size, unsigned long flags) |
| { |
| int is_ram = region_intersects(offset, size, "System RAM"); |
| void *addr = NULL; |
| |
| if (is_ram == REGION_MIXED) { |
| WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", |
| &offset, (unsigned long) size); |
| return NULL; |
| } |
| |
| /* Try all mapping types requested until one returns non-NULL */ |
| if (flags & MEMREMAP_WB) { |
| flags &= ~MEMREMAP_WB; |
| /* |
| * MEMREMAP_WB is special in that it can be satisifed |
| * from the direct map. Some archs depend on the |
| * capability of memremap() to autodetect cases where |
| * the requested range is potentially in "System RAM" |
| */ |
| if (is_ram == REGION_INTERSECTS) |
| addr = try_ram_remap(offset, size); |
| if (!addr) |
| addr = ioremap_cache(offset, size); |
| } |
| |
| /* |
| * If we don't have a mapping yet and more request flags are |
| * pending then we will be attempting to establish a new virtual |
| * address mapping. Enforce that this mapping is not aliasing |
| * "System RAM" |
| */ |
| if (!addr && is_ram == REGION_INTERSECTS && flags) { |
| WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", |
| &offset, (unsigned long) size); |
| return NULL; |
| } |
| |
| if (!addr && (flags & MEMREMAP_WT)) { |
| flags &= ~MEMREMAP_WT; |
| addr = ioremap_wt(offset, size); |
| } |
| |
| return addr; |
| } |
| EXPORT_SYMBOL(memremap); |
| |
| void memunmap(void *addr) |
| { |
| if (is_vmalloc_addr(addr)) |
| iounmap((void __iomem *) addr); |
| } |
| EXPORT_SYMBOL(memunmap); |
| |
| static void devm_memremap_release(struct device *dev, void *res) |
| { |
| memunmap(res); |
| } |
| |
| static int devm_memremap_match(struct device *dev, void *res, void *match_data) |
| { |
| return *(void **)res == match_data; |
| } |
| |
| void *devm_memremap(struct device *dev, resource_size_t offset, |
| size_t size, unsigned long flags) |
| { |
| void **ptr, *addr; |
| |
| ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL, |
| dev_to_node(dev)); |
| if (!ptr) |
| return ERR_PTR(-ENOMEM); |
| |
| addr = memremap(offset, size, flags); |
| if (addr) { |
| *ptr = addr; |
| devres_add(dev, ptr); |
| } else |
| devres_free(ptr); |
| |
| return addr; |
| } |
| EXPORT_SYMBOL(devm_memremap); |
| |
| void devm_memunmap(struct device *dev, void *addr) |
| { |
| WARN_ON(devres_release(dev, devm_memremap_release, |
| devm_memremap_match, addr)); |
| } |
| EXPORT_SYMBOL(devm_memunmap); |
| |
| pfn_t phys_to_pfn_t(phys_addr_t addr, unsigned long flags) |
| { |
| return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags); |
| } |
| EXPORT_SYMBOL(phys_to_pfn_t); |
| |
| #ifdef CONFIG_ZONE_DEVICE |
| static DEFINE_MUTEX(pgmap_lock); |
| static RADIX_TREE(pgmap_radix, GFP_KERNEL); |
| #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) |
| #define SECTION_SIZE (1UL << PA_SECTION_SHIFT) |
| |
| struct page_map { |
| struct resource res; |
| struct percpu_ref *ref; |
| struct dev_pagemap pgmap; |
| struct vmem_altmap altmap; |
| }; |
| |
| void get_zone_device_page(struct page *page) |
| { |
| percpu_ref_get(page->pgmap->ref); |
| } |
| EXPORT_SYMBOL(get_zone_device_page); |
| |
| void put_zone_device_page(struct page *page) |
| { |
| put_dev_pagemap(page->pgmap); |
| } |
| EXPORT_SYMBOL(put_zone_device_page); |
| |
| static void pgmap_radix_release(struct resource *res) |
| { |
| resource_size_t key, align_start, align_size, align_end; |
| |
| align_start = res->start & ~(SECTION_SIZE - 1); |
| align_size = ALIGN(resource_size(res), SECTION_SIZE); |
| align_end = align_start + align_size - 1; |
| |
| mutex_lock(&pgmap_lock); |
| for (key = res->start; key <= res->end; key += SECTION_SIZE) |
| radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT); |
| mutex_unlock(&pgmap_lock); |
| } |
| |
| static unsigned long pfn_first(struct page_map *page_map) |
| { |
| struct dev_pagemap *pgmap = &page_map->pgmap; |
| const struct resource *res = &page_map->res; |
| struct vmem_altmap *altmap = pgmap->altmap; |
| unsigned long pfn; |
| |
| pfn = res->start >> PAGE_SHIFT; |
| if (altmap) |
| pfn += vmem_altmap_offset(altmap); |
| return pfn; |
| } |
| |
| static unsigned long pfn_end(struct page_map *page_map) |
| { |
| const struct resource *res = &page_map->res; |
| |
| return (res->start + resource_size(res)) >> PAGE_SHIFT; |
| } |
| |
| #define for_each_device_pfn(pfn, map) \ |
| for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++) |
| |
| static void devm_memremap_pages_release(struct device *dev, void *data) |
| { |
| struct page_map *page_map = data; |
| struct resource *res = &page_map->res; |
| resource_size_t align_start, align_size; |
| struct dev_pagemap *pgmap = &page_map->pgmap; |
| |
| if (percpu_ref_tryget_live(pgmap->ref)) { |
| dev_WARN(dev, "%s: page mapping is still live!\n", __func__); |
| percpu_ref_put(pgmap->ref); |
| } |
| |
| /* pages are dead and unused, undo the arch mapping */ |
| align_start = res->start & ~(SECTION_SIZE - 1); |
| align_size = ALIGN(resource_size(res), SECTION_SIZE); |
| arch_remove_memory(align_start, align_size); |
| pgmap_radix_release(res); |
| dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc, |
| "%s: failed to free all reserved pages\n", __func__); |
| } |
| |
| /* assumes rcu_read_lock() held at entry */ |
| struct dev_pagemap *find_dev_pagemap(resource_size_t phys) |
| { |
| struct page_map *page_map; |
| |
| WARN_ON_ONCE(!rcu_read_lock_held()); |
| |
| page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT); |
| return page_map ? &page_map->pgmap : NULL; |
| } |
| |
| /** |
| * devm_memremap_pages - remap and provide memmap backing for the given resource |
| * @dev: hosting device for @res |
| * @res: "host memory" address range |
| * @ref: a live per-cpu reference count |
| * @altmap: optional descriptor for allocating the memmap from @res |
| * |
| * Notes: |
| * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time |
| * (or devm release event). |
| * |
| * 2/ @res is expected to be a host memory range that could feasibly be |
| * treated as a "System RAM" range, i.e. not a device mmio range, but |
| * this is not enforced. |
| */ |
| void *devm_memremap_pages(struct device *dev, struct resource *res, |
| struct percpu_ref *ref, struct vmem_altmap *altmap) |
| { |
| int is_ram = region_intersects(res->start, resource_size(res), |
| "System RAM"); |
| resource_size_t key, align_start, align_size, align_end; |
| struct dev_pagemap *pgmap; |
| struct page_map *page_map; |
| unsigned long pfn; |
| int error, nid; |
| |
| if (is_ram == REGION_MIXED) { |
| WARN_ONCE(1, "%s attempted on mixed region %pr\n", |
| __func__, res); |
| return ERR_PTR(-ENXIO); |
| } |
| |
| if (is_ram == REGION_INTERSECTS) |
| return __va(res->start); |
| |
| if (altmap && !IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) { |
| dev_err(dev, "%s: altmap requires CONFIG_SPARSEMEM_VMEMMAP=y\n", |
| __func__); |
| return ERR_PTR(-ENXIO); |
| } |
| |
| if (!ref) |
| return ERR_PTR(-EINVAL); |
| |
| page_map = devres_alloc_node(devm_memremap_pages_release, |
| sizeof(*page_map), GFP_KERNEL, dev_to_node(dev)); |
| if (!page_map) |
| return ERR_PTR(-ENOMEM); |
| pgmap = &page_map->pgmap; |
| |
| memcpy(&page_map->res, res, sizeof(*res)); |
| |
| pgmap->dev = dev; |
| if (altmap) { |
| memcpy(&page_map->altmap, altmap, sizeof(*altmap)); |
| pgmap->altmap = &page_map->altmap; |
| } |
| pgmap->ref = ref; |
| pgmap->res = &page_map->res; |
| |
| mutex_lock(&pgmap_lock); |
| error = 0; |
| align_start = res->start & ~(SECTION_SIZE - 1); |
| align_size = ALIGN(resource_size(res), SECTION_SIZE); |
| align_end = align_start + align_size - 1; |
| for (key = align_start; key <= align_end; key += SECTION_SIZE) { |
| struct dev_pagemap *dup; |
| |
| rcu_read_lock(); |
| dup = find_dev_pagemap(key); |
| rcu_read_unlock(); |
| if (dup) { |
| dev_err(dev, "%s: %pr collides with mapping for %s\n", |
| __func__, res, dev_name(dup->dev)); |
| error = -EBUSY; |
| break; |
| } |
| error = radix_tree_insert(&pgmap_radix, key >> PA_SECTION_SHIFT, |
| page_map); |
| if (error) { |
| dev_err(dev, "%s: failed: %d\n", __func__, error); |
| break; |
| } |
| } |
| mutex_unlock(&pgmap_lock); |
| if (error) |
| goto err_radix; |
| |
| nid = dev_to_node(dev); |
| if (nid < 0) |
| nid = numa_mem_id(); |
| |
| error = arch_add_memory(nid, align_start, align_size, true); |
| if (error) |
| goto err_add_memory; |
| |
| for_each_device_pfn(pfn, page_map) { |
| struct page *page = pfn_to_page(pfn); |
| |
| /* ZONE_DEVICE pages must never appear on a slab lru */ |
| list_force_poison(&page->lru); |
| page->pgmap = pgmap; |
| } |
| devres_add(dev, page_map); |
| return __va(res->start); |
| |
| err_add_memory: |
| err_radix: |
| pgmap_radix_release(res); |
| devres_free(page_map); |
| return ERR_PTR(error); |
| } |
| EXPORT_SYMBOL(devm_memremap_pages); |
| |
| unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
| { |
| /* number of pfns from base where pfn_to_page() is valid */ |
| return altmap->reserve + altmap->free; |
| } |
| |
| void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) |
| { |
| altmap->alloc -= nr_pfns; |
| } |
| |
| #ifdef CONFIG_SPARSEMEM_VMEMMAP |
| struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) |
| { |
| /* |
| * 'memmap_start' is the virtual address for the first "struct |
| * page" in this range of the vmemmap array. In the case of |
| * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple |
| * pointer arithmetic, so we can perform this to_vmem_altmap() |
| * conversion without concern for the initialization state of |
| * the struct page fields. |
| */ |
| struct page *page = (struct page *) memmap_start; |
| struct dev_pagemap *pgmap; |
| |
| /* |
| * Uncoditionally retrieve a dev_pagemap associated with the |
| * given physical address, this is only for use in the |
| * arch_{add|remove}_memory() for setting up and tearing down |
| * the memmap. |
| */ |
| rcu_read_lock(); |
| pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page))); |
| rcu_read_unlock(); |
| |
| return pgmap ? pgmap->altmap : NULL; |
| } |
| #endif /* CONFIG_SPARSEMEM_VMEMMAP */ |
| #endif /* CONFIG_ZONE_DEVICE */ |