--- /dev/null
-static void devmap_managed_enable_put(void *data)
+ /* 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/swapops.h>
+ #include <linux/types.h>
+ #include <linux/wait_bit.h>
+ #include <linux/xarray.h>
+
+ static DEFINE_XARRAY(pgmap_array);
+ #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
+ #define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
+
+ #ifdef CONFIG_DEV_PAGEMAP_OPS
+ DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
+ EXPORT_SYMBOL(devmap_managed_key);
+ static atomic_t devmap_managed_enable;
+
-static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
++static void devmap_managed_enable_put(void)
+ {
+ if (atomic_dec_and_test(&devmap_managed_enable))
+ static_branch_disable(&devmap_managed_key);
+ }
+
- return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
++static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
+ {
+ if (!pgmap->ops || !pgmap->ops->page_free) {
+ WARN(1, "Missing page_free method\n");
+ return -EINVAL;
+ }
+
+ if (atomic_inc_return(&devmap_managed_enable) == 1)
+ static_branch_enable(&devmap_managed_key);
-static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
++ return 0;
+ }
+ #else
-static void devm_memremap_pages_release(void *data)
++static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
+ {
+ return -EINVAL;
+ }
++static void devmap_managed_enable_put(void)
++{
++}
+ #endif /* CONFIG_DEV_PAGEMAP_OPS */
+
+ static void pgmap_array_delete(struct resource *res)
+ {
+ xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
+ NULL, GFP_KERNEL);
+ synchronize_rcu();
+ }
+
+ static unsigned long pfn_first(struct dev_pagemap *pgmap)
+ {
+ return PHYS_PFN(pgmap->res.start) +
+ vmem_altmap_offset(pgmap_altmap(pgmap));
+ }
+
+ static unsigned long pfn_end(struct dev_pagemap *pgmap)
+ {
+ const struct resource *res = &pgmap->res;
+
+ return (res->start + resource_size(res)) >> 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) \
+ for (pfn = pfn_first(map); pfn < pfn_end(map); 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;
+ }
+
- struct dev_pagemap *pgmap = data;
- struct device *dev = pgmap->dev;
++void memunmap_pages(struct dev_pagemap *pgmap)
+ {
- dev_WARN_ONCE(dev, pgmap->altmap.alloc,
- "%s: failed to free all reserved pages\n", __func__);
+ struct resource *res = &pgmap->res;
+ unsigned long pfn;
+ int nid;
+
+ dev_pagemap_kill(pgmap);
+ for_each_device_pfn(pfn, pgmap)
+ put_page(pfn_to_page(pfn));
+ dev_pagemap_cleanup(pgmap);
+
+ /* pages are dead and unused, undo the arch mapping */
+ nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start)));
+
+ mem_hotplug_begin();
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+ pfn = PHYS_PFN(res->start);
+ __remove_pages(page_zone(pfn_to_page(pfn)), pfn,
+ PHYS_PFN(resource_size(res)), NULL);
+ } else {
+ arch_remove_memory(nid, res->start, resource_size(res),
+ pgmap_altmap(pgmap));
+ kasan_remove_zero_shadow(__va(res->start), resource_size(res));
+ }
+ mem_hotplug_done();
+
+ untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
+ pgmap_array_delete(res);
-/**
- * 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/ 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.
++ WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
++ devmap_managed_enable_put();
++}
++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);
+ }
+
-void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
++/*
++ * Not device managed version of dev_memremap_pages, undone by
++ * memunmap_pages(). Please use dev_memremap_pages if you have a struct
++ * device available.
+ */
- int error, nid, is_ram;
++void *memremap_pages(struct dev_pagemap *pgmap, int nid)
+ {
+ struct resource *res = &pgmap->res;
+ struct dev_pagemap *conflict_pgmap;
+ struct mhp_restrictions restrictions = {
+ /*
+ * We do not want any optional features only our own memmap
+ */
+ .altmap = pgmap_altmap(pgmap),
+ };
+ pgprot_t pgprot = PAGE_KERNEL;
- error = devmap_managed_enable_get(dev, pgmap);
++ int error, is_ram;
+ bool need_devmap_managed = true;
+
+ 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);
+ }
+ 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_DEVDAX:
+ case MEMORY_DEVICE_PCI_P2PDMA:
+ need_devmap_managed = false;
+ 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);
+ }
+ }
+
+ if (need_devmap_managed) {
- dev_WARN(dev, "Conflicting mapping in same section\n");
++ error = devmap_managed_enable_get(pgmap);
+ if (error)
+ return ERR_PTR(error);
+ }
+
+ conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
+ if (conflict_pgmap) {
- dev_WARN(dev, "Conflicting mapping in same section\n");
++ WARN(1, "Conflicting mapping in same section\n");
+ put_dev_pagemap(conflict_pgmap);
+ error = -ENOMEM;
+ goto err_array;
+ }
+
+ conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
+ if (conflict_pgmap) {
- pgmap->dev = dev;
-
++ WARN(1, "Conflicting mapping in same section\n");
+ put_dev_pagemap(conflict_pgmap);
+ error = -ENOMEM;
+ goto err_array;
+ }
+
+ is_ram = region_intersects(res->start, resource_size(res),
+ IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
+
+ if (is_ram != REGION_DISJOINT) {
+ WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
+ is_ram == REGION_MIXED ? "mixed" : "ram", res);
+ error = -ENXIO;
+ goto err_array;
+ }
+
- nid = dev_to_node(dev);
+ error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
+ PHYS_PFN(res->end), pgmap, GFP_KERNEL));
+ if (error)
+ goto err_array;
+
-
- error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
- pgmap);
- if (error)
- return ERR_PTR(error);
-
+ if (nid < 0)
+ nid = numa_mem_id();
+
+ error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0,
+ resource_size(res));
+ 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(res->start),
+ PHYS_PFN(resource_size(res)), &restrictions);
+ } else {
+ error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
+ if (error) {
+ mem_hotplug_done();
+ goto err_kasan;
+ }
+
+ error = arch_add_memory(nid, res->start, resource_size(res),
+ &restrictions);
+ }
+
+ if (!error) {
+ struct zone *zone;
+
+ zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
+ move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
+ PHYS_PFN(resource_size(res)), restrictions.altmap);
+ }
+
+ 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(res->start),
+ PHYS_PFN(resource_size(res)), pgmap);
+ percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
+ return __va(res->start);
+
+ err_add_memory:
+ kasan_remove_zero_shadow(__va(res->start), resource_size(res));
+ err_kasan:
+ untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
+ err_pfn_remap:
+ pgmap_array_delete(res);
+ err_array:
+ dev_pagemap_kill(pgmap);
+ dev_pagemap_cleanup(pgmap);
++ devmap_managed_enable_put();
+ return ERR_PTR(error);
+ }
++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/ 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 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->res.start && phys <= pgmap->res.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 __put_devmap_managed_page(struct page *page)
+ {
+ int count = page_ref_dec_return(page);
+
+ /*
+ * If refcount is 1 then page is freed and refcount is stable as nobody
+ * holds a reference on the page.
+ */
+ if (count == 1) {
+ /* Clear Active bit in case of parallel mark_page_accessed */
+ __ClearPageActive(page);
+ __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.
+ */
+ if (is_device_private_page(page))
+ page->mapping = NULL;
+
+ page->pgmap->ops->page_free(page);
+ } else if (!count)
+ __put_page(page);
+ }
+ EXPORT_SYMBOL(__put_devmap_managed_page);
+ #endif /* CONFIG_DEV_PAGEMAP_OPS */
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