| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* Copyright(c) 2015 Intel Corporation. All rights reserved. */ |
| #include <linux/device.h> |
| #include <linux/io.h> |
| #include <linux/kasan.h> |
| #include <linux/memory_hotplug.h> |
| #include <linux/mm.h> |
| #include <linux/pfn_t.h> |
| #include <linux/swap.h> |
| #include <linux/mmzone.h> |
| #include <linux/swapops.h> |
| #include <linux/types.h> |
| #include <linux/wait_bit.h> |
| #include <linux/xarray.h> |
| |
| static DEFINE_XARRAY(pgmap_array); |
| |
| /* |
| * The memremap() and memremap_pages() interfaces are alternately used |
| * to map persistent memory namespaces. These interfaces place different |
| * constraints on the alignment and size of the mapping (namespace). |
| * memremap() can map individual PAGE_SIZE pages. memremap_pages() can |
| * only map subsections (2MB), and at least one architecture (PowerPC) |
| * the minimum mapping granularity of memremap_pages() is 16MB. |
| * |
| * The role of memremap_compat_align() is to communicate the minimum |
| * arch supported alignment of a namespace such that it can freely |
| * switch modes without violating the arch constraint. Namely, do not |
| * allow a namespace to be PAGE_SIZE aligned since that namespace may be |
| * reconfigured into a mode that requires SUBSECTION_SIZE alignment. |
| */ |
| #ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN |
| unsigned long memremap_compat_align(void) |
| { |
| return SUBSECTION_SIZE; |
| } |
| EXPORT_SYMBOL_GPL(memremap_compat_align); |
| #endif |
| |
| #ifdef CONFIG_DEV_PAGEMAP_OPS |
| DEFINE_STATIC_KEY_FALSE(devmap_managed_key); |
| EXPORT_SYMBOL(devmap_managed_key); |
| |
| static void devmap_managed_enable_put(struct dev_pagemap *pgmap) |
| { |
| if (pgmap->type == MEMORY_DEVICE_PRIVATE || |
| pgmap->type == MEMORY_DEVICE_FS_DAX) |
| static_branch_dec(&devmap_managed_key); |
| } |
| |
| static void devmap_managed_enable_get(struct dev_pagemap *pgmap) |
| { |
| if (pgmap->type == MEMORY_DEVICE_PRIVATE || |
| pgmap->type == MEMORY_DEVICE_FS_DAX) |
| static_branch_inc(&devmap_managed_key); |
| } |
| #else |
| static void devmap_managed_enable_get(struct dev_pagemap *pgmap) |
| { |
| } |
| static void devmap_managed_enable_put(struct dev_pagemap *pgmap) |
| { |
| } |
| #endif /* CONFIG_DEV_PAGEMAP_OPS */ |
| |
| static void pgmap_array_delete(struct range *range) |
| { |
| xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->end), |
| NULL, GFP_KERNEL); |
| synchronize_rcu(); |
| } |
| |
| static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id) |
| { |
| struct range *range = &pgmap->ranges[range_id]; |
| unsigned long pfn = PHYS_PFN(range->start); |
| |
| if (range_id) |
| return pfn; |
| return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); |
| } |
| |
| bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) |
| { |
| int i; |
| |
| for (i = 0; i < pgmap->nr_range; i++) { |
| struct range *range = &pgmap->ranges[i]; |
| |
| if (pfn >= PHYS_PFN(range->start) && |
| pfn <= PHYS_PFN(range->end)) |
| return pfn >= pfn_first(pgmap, i); |
| } |
| |
| return false; |
| } |
| |
| static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) |
| { |
| const struct range *range = &pgmap->ranges[range_id]; |
| |
| return (range->start + range_len(range)) >> PAGE_SHIFT; |
| } |
| |
| static unsigned long pfn_next(unsigned long pfn) |
| { |
| if (pfn % 1024 == 0) |
| cond_resched(); |
| return pfn + 1; |
| } |
| |
| #define for_each_device_pfn(pfn, map, i) \ |
| for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn)) |
| |
| static void dev_pagemap_kill(struct dev_pagemap *pgmap) |
| { |
| if (pgmap->ops && pgmap->ops->kill) |
| pgmap->ops->kill(pgmap); |
| else |
| percpu_ref_kill(pgmap->ref); |
| } |
| |
| static void dev_pagemap_cleanup(struct dev_pagemap *pgmap) |
| { |
| if (pgmap->ops && pgmap->ops->cleanup) { |
| pgmap->ops->cleanup(pgmap); |
| } else { |
| wait_for_completion(&pgmap->done); |
| percpu_ref_exit(pgmap->ref); |
| } |
| /* |
| * Undo the pgmap ref assignment for the internal case as the |
| * caller may re-enable the same pgmap. |
| */ |
| if (pgmap->ref == &pgmap->internal_ref) |
| pgmap->ref = NULL; |
| } |
| |
| static void pageunmap_range(struct dev_pagemap *pgmap, int range_id) |
| { |
| struct range *range = &pgmap->ranges[range_id]; |
| struct page *first_page; |
| int nid; |
| |
| /* make sure to access a memmap that was actually initialized */ |
| first_page = pfn_to_page(pfn_first(pgmap, range_id)); |
| |
| /* pages are dead and unused, undo the arch mapping */ |
| nid = page_to_nid(first_page); |
| |
| mem_hotplug_begin(); |
| remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start), |
| PHYS_PFN(range_len(range))); |
| if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
| __remove_pages(PHYS_PFN(range->start), |
| PHYS_PFN(range_len(range)), NULL); |
| } else { |
| arch_remove_memory(nid, range->start, range_len(range), |
| pgmap_altmap(pgmap)); |
| kasan_remove_zero_shadow(__va(range->start), range_len(range)); |
| } |
| mem_hotplug_done(); |
| |
| untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); |
| pgmap_array_delete(range); |
| } |
| |
| void memunmap_pages(struct dev_pagemap *pgmap) |
| { |
| unsigned long pfn; |
| int i; |
| |
| dev_pagemap_kill(pgmap); |
| for (i = 0; i < pgmap->nr_range; i++) |
| for_each_device_pfn(pfn, pgmap, i) |
| put_page(pfn_to_page(pfn)); |
| dev_pagemap_cleanup(pgmap); |
| |
| for (i = 0; i < pgmap->nr_range; i++) |
| pageunmap_range(pgmap, i); |
| |
| WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); |
| devmap_managed_enable_put(pgmap); |
| } |
| EXPORT_SYMBOL_GPL(memunmap_pages); |
| |
| static void devm_memremap_pages_release(void *data) |
| { |
| memunmap_pages(data); |
| } |
| |
| static void dev_pagemap_percpu_release(struct percpu_ref *ref) |
| { |
| struct dev_pagemap *pgmap = |
| container_of(ref, struct dev_pagemap, internal_ref); |
| |
| complete(&pgmap->done); |
| } |
| |
| static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, |
| int range_id, int nid) |
| { |
| struct range *range = &pgmap->ranges[range_id]; |
| struct dev_pagemap *conflict_pgmap; |
| int error, is_ram; |
| |
| if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0, |
| "altmap not supported for multiple ranges\n")) |
| return -EINVAL; |
| |
| conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL); |
| if (conflict_pgmap) { |
| WARN(1, "Conflicting mapping in same section\n"); |
| put_dev_pagemap(conflict_pgmap); |
| return -ENOMEM; |
| } |
| |
| conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL); |
| if (conflict_pgmap) { |
| WARN(1, "Conflicting mapping in same section\n"); |
| put_dev_pagemap(conflict_pgmap); |
| return -ENOMEM; |
| } |
| |
| is_ram = region_intersects(range->start, range_len(range), |
| IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); |
| |
| if (is_ram != REGION_DISJOINT) { |
| WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n", |
| is_ram == REGION_MIXED ? "mixed" : "ram", |
| range->start, range->end); |
| return -ENXIO; |
| } |
| |
| error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start), |
| PHYS_PFN(range->end), pgmap, GFP_KERNEL)); |
| if (error) |
| return error; |
| |
| if (nid < 0) |
| nid = numa_mem_id(); |
| |
| error = track_pfn_remap(NULL, ¶ms->pgprot, PHYS_PFN(range->start), 0, |
| range_len(range)); |
| if (error) |
| goto err_pfn_remap; |
| |
| mem_hotplug_begin(); |
| |
| /* |
| * For device private memory we call add_pages() as we only need to |
| * allocate and initialize struct page for the device memory. More- |
| * over the device memory is un-accessible thus we do not want to |
| * create a linear mapping for the memory like arch_add_memory() |
| * would do. |
| * |
| * For all other device memory types, which are accessible by |
| * the CPU, we do want the linear mapping and thus use |
| * arch_add_memory(). |
| */ |
| if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
| error = add_pages(nid, PHYS_PFN(range->start), |
| PHYS_PFN(range_len(range)), params); |
| } else { |
| error = kasan_add_zero_shadow(__va(range->start), range_len(range)); |
| if (error) { |
| mem_hotplug_done(); |
| goto err_kasan; |
| } |
| |
| error = arch_add_memory(nid, range->start, range_len(range), |
| params); |
| } |
| |
| if (!error) { |
| struct zone *zone; |
| |
| zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; |
| move_pfn_range_to_zone(zone, PHYS_PFN(range->start), |
| PHYS_PFN(range_len(range)), params->altmap, |
| MIGRATE_MOVABLE); |
| } |
| |
| mem_hotplug_done(); |
| if (error) |
| goto err_add_memory; |
| |
| /* |
| * Initialization of the pages has been deferred until now in order |
| * to allow us to do the work while not holding the hotplug lock. |
| */ |
| memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], |
| PHYS_PFN(range->start), |
| PHYS_PFN(range_len(range)), pgmap); |
| percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id) |
| - pfn_first(pgmap, range_id)); |
| return 0; |
| |
| err_add_memory: |
| kasan_remove_zero_shadow(__va(range->start), range_len(range)); |
| err_kasan: |
| untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); |
| err_pfn_remap: |
| pgmap_array_delete(range); |
| return error; |
| } |
| |
| |
| /* |
| * Not device managed version of dev_memremap_pages, undone by |
| * memunmap_pages(). Please use dev_memremap_pages if you have a struct |
| * device available. |
| */ |
| void *memremap_pages(struct dev_pagemap *pgmap, int nid) |
| { |
| struct mhp_params params = { |
| .altmap = pgmap_altmap(pgmap), |
| .pgprot = PAGE_KERNEL, |
| }; |
| const int nr_range = pgmap->nr_range; |
| int error, i; |
| |
| if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) |
| return ERR_PTR(-EINVAL); |
| |
| switch (pgmap->type) { |
| case MEMORY_DEVICE_PRIVATE: |
| if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) { |
| WARN(1, "Device private memory not supported\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| if (!pgmap->ops || !pgmap->ops->migrate_to_ram) { |
| WARN(1, "Missing migrate_to_ram method\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| if (!pgmap->ops->page_free) { |
| WARN(1, "Missing page_free method\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| if (!pgmap->owner) { |
| WARN(1, "Missing owner\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| break; |
| case MEMORY_DEVICE_FS_DAX: |
| if (!IS_ENABLED(CONFIG_ZONE_DEVICE) || |
| IS_ENABLED(CONFIG_FS_DAX_LIMITED)) { |
| WARN(1, "File system DAX not supported\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| params.pgprot = pgprot_decrypted(params.pgprot); |
| break; |
| case MEMORY_DEVICE_GENERIC: |
| break; |
| case MEMORY_DEVICE_PCI_P2PDMA: |
| params.pgprot = pgprot_noncached(params.pgprot); |
| break; |
| default: |
| WARN(1, "Invalid pgmap type %d\n", pgmap->type); |
| break; |
| } |
| |
| if (!pgmap->ref) { |
| if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup)) |
| return ERR_PTR(-EINVAL); |
| |
| init_completion(&pgmap->done); |
| error = percpu_ref_init(&pgmap->internal_ref, |
| dev_pagemap_percpu_release, 0, GFP_KERNEL); |
| if (error) |
| return ERR_PTR(error); |
| pgmap->ref = &pgmap->internal_ref; |
| } else { |
| if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) { |
| WARN(1, "Missing reference count teardown definition\n"); |
| return ERR_PTR(-EINVAL); |
| } |
| } |
| |
| devmap_managed_enable_get(pgmap); |
| |
| /* |
| * Clear the pgmap nr_range as it will be incremented for each |
| * successfully processed range. This communicates how many |
| * regions to unwind in the abort case. |
| */ |
| pgmap->nr_range = 0; |
| error = 0; |
| for (i = 0; i < nr_range; i++) { |
| error = pagemap_range(pgmap, ¶ms, i, nid); |
| if (error) |
| break; |
| pgmap->nr_range++; |
| } |
| |
| if (i < nr_range) { |
| memunmap_pages(pgmap); |
| pgmap->nr_range = nr_range; |
| return ERR_PTR(error); |
| } |
| |
| return __va(pgmap->ranges[0].start); |
| } |
| EXPORT_SYMBOL_GPL(memremap_pages); |
| |
| /** |
| * devm_memremap_pages - remap and provide memmap backing for the given resource |
| * @dev: hosting device for @res |
| * @pgmap: pointer to a struct dev_pagemap |
| * |
| * Notes: |
| * 1/ At a minimum the res and type members of @pgmap must be initialized |
| * by the caller before passing it to this function |
| * |
| * 2/ The altmap field may optionally be initialized, in which case |
| * PGMAP_ALTMAP_VALID must be set in pgmap->flags. |
| * |
| * 3/ The ref field may optionally be provided, in which pgmap->ref must be |
| * 'live' on entry and will be killed and reaped at |
| * devm_memremap_pages_release() time, or if this routine fails. |
| * |
| * 4/ range 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 dev_pagemap *pgmap) |
| { |
| int error; |
| void *ret; |
| |
| ret = memremap_pages(pgmap, dev_to_node(dev)); |
| if (IS_ERR(ret)) |
| return ret; |
| |
| error = devm_add_action_or_reset(dev, devm_memremap_pages_release, |
| pgmap); |
| if (error) |
| return ERR_PTR(error); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(devm_memremap_pages); |
| |
| void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) |
| { |
| devm_release_action(dev, devm_memremap_pages_release, pgmap); |
| } |
| EXPORT_SYMBOL_GPL(devm_memunmap_pages); |
| |
| unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
| { |
| /* number of pfns from base where pfn_to_page() is valid */ |
| if (altmap) |
| return altmap->reserve + altmap->free; |
| return 0; |
| } |
| |
| void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) |
| { |
| altmap->alloc -= nr_pfns; |
| } |
| |
| /** |
| * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn |
| * @pfn: page frame number to lookup page_map |
| * @pgmap: optional known pgmap that already has a reference |
| * |
| * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap |
| * is non-NULL but does not cover @pfn the reference to it will be released. |
| */ |
| struct dev_pagemap *get_dev_pagemap(unsigned long pfn, |
| struct dev_pagemap *pgmap) |
| { |
| resource_size_t phys = PFN_PHYS(pfn); |
| |
| /* |
| * In the cached case we're already holding a live reference. |
| */ |
| if (pgmap) { |
| if (phys >= pgmap->range.start && phys <= pgmap->range.end) |
| return pgmap; |
| put_dev_pagemap(pgmap); |
| } |
| |
| /* fall back to slow path lookup */ |
| rcu_read_lock(); |
| pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); |
| if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) |
| pgmap = NULL; |
| rcu_read_unlock(); |
| |
| return pgmap; |
| } |
| EXPORT_SYMBOL_GPL(get_dev_pagemap); |
| |
| #ifdef CONFIG_DEV_PAGEMAP_OPS |
| void free_devmap_managed_page(struct page *page) |
| { |
| /* notify page idle for dax */ |
| if (!is_device_private_page(page)) { |
| wake_up_var(&page->_refcount); |
| return; |
| } |
| |
| __ClearPageWaiters(page); |
| |
| mem_cgroup_uncharge(page); |
| |
| /* |
| * When a device_private page is freed, the page->mapping field |
| * may still contain a (stale) mapping value. For example, the |
| * lower bits of page->mapping may still identify the page as an |
| * anonymous page. Ultimately, this entire field is just stale |
| * and wrong, and it will cause errors if not cleared. One |
| * example is: |
| * |
| * migrate_vma_pages() |
| * migrate_vma_insert_page() |
| * page_add_new_anon_rmap() |
| * __page_set_anon_rmap() |
| * ...checks page->mapping, via PageAnon(page) call, |
| * and incorrectly concludes that the page is an |
| * anonymous page. Therefore, it incorrectly, |
| * silently fails to set up the new anon rmap. |
| * |
| * For other types of ZONE_DEVICE pages, migration is either |
| * handled differently or not done at all, so there is no need |
| * to clear page->mapping. |
| */ |
| page->mapping = NULL; |
| page->pgmap->ops->page_free(page); |
| } |
| #endif /* CONFIG_DEV_PAGEMAP_OPS */ |