// 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(struct dev_pagemap *pgmap, unsigned long pfn) { if (pfn % (1024 << pgmap->vmemmap_shift)) cond_resched(); return pfn + pgmap_vmemmap_nr(pgmap); } static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id) { return (pfn_end(pgmap, range_id) - pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift; } #define for_each_device_pfn(pfn, map, i) \ for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); \ pfn = pfn_next(map, pfn)) static void pageunmap_range(struct dev_pagemap *pgmap, int range_id) { struct range *range = &pgmap->ranges[range_id]; struct page *first_page; /* 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 */ 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(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; percpu_ref_kill(&pgmap->ref); for (i = 0; i < pgmap->nr_range; i++) for_each_device_pfn(pfn, pgmap, i) put_page(pfn_to_page(pfn)); wait_for_completion(&pgmap->done); percpu_ref_exit(&pgmap->ref); 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, ref); complete(&pgmap->done); } static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, int range_id, int nid) { const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE; 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; if (!mhp_range_allowed(range->start, range_len(range), !is_private)) { error = -EINVAL; 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 (is_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_len(pgmap, range_id)); return 0; err_add_memory: if (!is_private) 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); } 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; } init_completion(&pgmap->done); error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0, GFP_KERNEL); if (error) return ERR_PTR(error); 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_folio(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 */