[linux-2.6-block.git] / mm / memremap.c

/* 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 void devmap_managed_enable_put(void *data)
{
	if (atomic_dec_and_test(&devmap_managed_enable))
		static_branch_disable(&devmap_managed_key);
}

static int devmap_managed_enable_get(struct device *dev, 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);
	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
}
#else
static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
{
	return -EINVAL;
}
#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;
}

static void devm_memremap_pages_release(void *data)
{
	struct dev_pagemap *pgmap = data;
	struct device *dev = pgmap->dev;
	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);
	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
		      "%s: failed to free all reserved pages\n", __func__);
}

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);
}

/**
 * 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)
{
	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;
	int error, nid, 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) {
		error = devmap_managed_enable_get(dev, 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");
		put_dev_pagemap(conflict_pgmap);
		error = -ENOMEM;
		goto err_array;
	}

	conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
	if (conflict_pgmap) {
		dev_WARN(dev, "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;
	}

	pgmap->dev = 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;

	nid = dev_to_node(dev);
	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));

	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
			pgmap);
	if (error)
		return ERR_PTR(error);

	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);
	return ERR_PTR(error);
}
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 */
Commit	Line	Data
5981690d DW	1	/* SPDX-License-Identifier: GPL-2.0 */
5981690d DW	2	/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
7d3dcf26	3	#include <linux/device.h>
92281dee	4	#include <linux/io.h>
0207df4f	5	#include <linux/kasan.h>
41e94a85	6	#include <linux/memory_hotplug.h>
bcfa4b72 MW	7	#include <linux/mm.h>
bcfa4b72 MW	8	#include <linux/pfn_t.h>
5042db43 JG	9	#include <linux/swap.h>
5042db43 JG	10	#include <linux/swapops.h>
bcfa4b72	11	#include <linux/types.h>
e7638488	12	#include <linux/wait_bit.h>
bcfa4b72	13	#include <linux/xarray.h>
92281dee	14
bcfa4b72	15	static DEFINE_XARRAY(pgmap_array);
9476df7d DW	16	#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
	17	#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
	18
f6a55e1a CH	19	#ifdef CONFIG_DEV_PAGEMAP_OPS
	20	DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
	21	EXPORT_SYMBOL(devmap_managed_key);
	22	static atomic_t devmap_managed_enable;
	23
	24	static void devmap_managed_enable_put(void *data)
	25	{
	26	if (atomic_dec_and_test(&devmap_managed_enable))
	27	static_branch_disable(&devmap_managed_key);
	28	}
	29
	30	static int devmap_managed_enable_get(struct device dev, struct dev_pagemap pgmap)
	31	{
24917f6b	32	if (!pgmap->ops \|\| !pgmap->ops->page_free) {
f6a55e1a CH	33	WARN(1, "Missing page_free method\n");
	34	return -EINVAL;
	35	}
	36
	37	if (atomic_inc_return(&devmap_managed_enable) == 1)
	38	static_branch_enable(&devmap_managed_key);
	39	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
	40	}
	41	#else
	42	static int devmap_managed_enable_get(struct device dev, struct dev_pagemap pgmap)
	43	{
	44	return -EINVAL;
	45	}
	46	#endif /* CONFIG_DEV_PAGEMAP_OPS */
	47
bcfa4b72	48	static void pgmap_array_delete(struct resource *res)
ab1b597e	49	{
bcfa4b72 MW	50	xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
bcfa4b72 MW	51	NULL, GFP_KERNEL);
ab1b597e	52	synchronize_rcu();
9476df7d DW	53	}
9476df7d DW	54
e7744aa2	55	static unsigned long pfn_first(struct dev_pagemap *pgmap)
5c2c2587	56	{
7cc7867f	57	return PHYS_PFN(pgmap->res.start) +
514caf23	58	vmem_altmap_offset(pgmap_altmap(pgmap));
5c2c2587 DW	59	}
5c2c2587 DW	60
e7744aa2	61	static unsigned long pfn_end(struct dev_pagemap *pgmap)
5c2c2587	62	{
e7744aa2	63	const struct resource *res = &pgmap->res;
5c2c2587 DW	64
	65	return (res->start + resource_size(res)) >> PAGE_SHIFT;
	66	}
	67
949b9325 DW	68	static unsigned long pfn_next(unsigned long pfn)
	69	{
	70	if (pfn % 1024 == 0)
	71	cond_resched();
	72	return pfn + 1;
	73	}
	74
5c2c2587	75	#define for_each_device_pfn(pfn, map) \
949b9325	76	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
5c2c2587	77
24917f6b CH	78	static void dev_pagemap_kill(struct dev_pagemap *pgmap)
	79	{
	80	if (pgmap->ops && pgmap->ops->kill)
	81	pgmap->ops->kill(pgmap);
	82	else
	83	percpu_ref_kill(pgmap->ref);
	84	}
	85
	86	static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
	87	{
	88	if (pgmap->ops && pgmap->ops->cleanup) {
	89	pgmap->ops->cleanup(pgmap);
	90	} else {
	91	wait_for_completion(&pgmap->done);
	92	percpu_ref_exit(pgmap->ref);
	93	}
06282373 DW	94	/*
	95	* Undo the pgmap ref assignment for the internal case as the
	96	* caller may re-enable the same pgmap.
	97	*/
	98	if (pgmap->ref == &pgmap->internal_ref)
	99	pgmap->ref = NULL;
24917f6b CH	100	}
24917f6b CH	101
e8d51348	102	static void devm_memremap_pages_release(void *data)
41e94a85	103	{
e7744aa2	104	struct dev_pagemap *pgmap = data;
e8d51348	105	struct device *dev = pgmap->dev;
e7744aa2	106	struct resource *res = &pgmap->res;
71389703	107	unsigned long pfn;
2c2a5af6	108	int nid;
71389703	109
24917f6b	110	dev_pagemap_kill(pgmap);
e7744aa2	111	for_each_device_pfn(pfn, pgmap)
71389703	112	put_page(pfn_to_page(pfn));
24917f6b	113	dev_pagemap_cleanup(pgmap);
9476df7d	114
41e94a85	115	/* pages are dead and unused, undo the arch mapping */
7cc7867f	116	nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start)));
2c2a5af6	117
f931ab47	118	mem_hotplug_begin();
69324b8f	119	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
7cc7867f	120	pfn = PHYS_PFN(res->start);
69324b8f	121	__remove_pages(page_zone(pfn_to_page(pfn)), pfn,
7cc7867f	122	PHYS_PFN(resource_size(res)), NULL);
69324b8f	123	} else {
7cc7867f	124	arch_remove_memory(nid, res->start, resource_size(res),
514caf23	125	pgmap_altmap(pgmap));
7cc7867f	126	kasan_remove_zero_shadow(__va(res->start), resource_size(res));
69324b8f	127	}
f931ab47	128	mem_hotplug_done();
b5d24fda	129
7cc7867f	130	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
bcfa4b72	131	pgmap_array_delete(res);
e7744aa2 LG	132	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
e7744aa2 LG	133	"%s: failed to free all reserved pages\n", __func__);
9476df7d DW	134	}
9476df7d DW	135
24917f6b CH	136	static void dev_pagemap_percpu_release(struct percpu_ref *ref)
	137	{
	138	struct dev_pagemap *pgmap =
	139	container_of(ref, struct dev_pagemap, internal_ref);
	140
	141	complete(&pgmap->done);
	142	}
	143
4b94ffdc DW	144	/**
	145	* devm_memremap_pages - remap and provide memmap backing for the given resource
	146	* @dev: hosting device for @res
a95c90f1	147	* @pgmap: pointer to a struct dev_pagemap
4b94ffdc	148	*
5c2c2587	149	* Notes:
24917f6b CH	150	* 1/ At a minimum the res and type members of @pgmap must be initialized
24917f6b CH	151	* by the caller before passing it to this function
e8d51348	152	*
514caf23 CH	153	* 2/ The altmap field may optionally be initialized, in which case
514caf23 CH	154	* PGMAP_ALTMAP_VALID must be set in pgmap->flags.
e8d51348	155	*
24917f6b CH	156	* 3/ The ref field may optionally be provided, in which pgmap->ref must be
	157	* 'live' on entry and will be killed and reaped at
	158	* devm_memremap_pages_release() time, or if this routine fails.
5c2c2587	159	*
e8d51348	160	* 4/ res is expected to be a host memory range that could feasibly be
5c2c2587 DW	161	* treated as a "System RAM" range, i.e. not a device mmio range, but
5c2c2587 DW	162	* this is not enforced.
4b94ffdc	163	*/
e8d51348	164	void devm_memremap_pages(struct device dev, struct dev_pagemap *pgmap)
41e94a85	165	{
949b9325	166	struct resource *res = &pgmap->res;
966cf44f	167	struct dev_pagemap *conflict_pgmap;
940519f0 MH	168	struct mhp_restrictions restrictions = {
	169	/*
	170	* We do not want any optional features only our own memmap
7cc7867f	171	*/
514caf23	172	.altmap = pgmap_altmap(pgmap),
940519f0	173	};
9049771f	174	pgprot_t pgprot = PAGE_KERNEL;
949b9325	175	int error, nid, is_ram;
f6a55e1a	176	bool need_devmap_managed = true;
5f29a77c	177
3ed2dcdf CH	178	switch (pgmap->type) {
	179	case MEMORY_DEVICE_PRIVATE:
	180	if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
	181	WARN(1, "Device private memory not supported\n");
	182	return ERR_PTR(-EINVAL);
	183	}
897e6365 CH	184	if (!pgmap->ops \|\| !pgmap->ops->migrate_to_ram) {
	185	WARN(1, "Missing migrate_to_ram method\n");
	186	return ERR_PTR(-EINVAL);
	187	}
3ed2dcdf CH	188	break;
	189	case MEMORY_DEVICE_FS_DAX:
	190	if (!IS_ENABLED(CONFIG_ZONE_DEVICE) \|\|
	191	IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
	192	WARN(1, "File system DAX not supported\n");
	193	return ERR_PTR(-EINVAL);
	194	}
	195	break;
	196	case MEMORY_DEVICE_DEVDAX:
	197	case MEMORY_DEVICE_PCI_P2PDMA:
f6a55e1a	198	need_devmap_managed = false;
3ed2dcdf CH	199	break;
	200	default:
	201	WARN(1, "Invalid pgmap type %d\n", pgmap->type);
	202	break;
	203	}
	204
24917f6b CH	205	if (!pgmap->ref) {
	206	if (pgmap->ops && (pgmap->ops->kill \|\| pgmap->ops->cleanup))
	207	return ERR_PTR(-EINVAL);
	208
	209	init_completion(&pgmap->done);
	210	error = percpu_ref_init(&pgmap->internal_ref,
	211	dev_pagemap_percpu_release, 0, GFP_KERNEL);
	212	if (error)
	213	return ERR_PTR(error);
	214	pgmap->ref = &pgmap->internal_ref;
	215	} else {
	216	if (!pgmap->ops \|\| !pgmap->ops->kill \|\| !pgmap->ops->cleanup) {
	217	WARN(1, "Missing reference count teardown definition\n");
	218	return ERR_PTR(-EINVAL);
	219	}
50f44ee7	220	}
a95c90f1	221
f6a55e1a CH	222	if (need_devmap_managed) {
	223	error = devmap_managed_enable_get(dev, pgmap);
	224	if (error)
	225	return ERR_PTR(error);
	226	}
	227
7cc7867f	228	conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
15d36fec DJ	229	if (conflict_pgmap) {
	230	dev_WARN(dev, "Conflicting mapping in same section\n");
	231	put_dev_pagemap(conflict_pgmap);
50f44ee7 DW	232	error = -ENOMEM;
50f44ee7 DW	233	goto err_array;
15d36fec DJ	234	}
15d36fec DJ	235
7cc7867f	236	conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
15d36fec DJ	237	if (conflict_pgmap) {
	238	dev_WARN(dev, "Conflicting mapping in same section\n");
	239	put_dev_pagemap(conflict_pgmap);
50f44ee7 DW	240	error = -ENOMEM;
50f44ee7 DW	241	goto err_array;
15d36fec DJ	242	}
15d36fec DJ	243
7cc7867f	244	is_ram = region_intersects(res->start, resource_size(res),
d37a14bb	245	IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
41e94a85	246
06489cfb DW	247	if (is_ram != REGION_DISJOINT) {
	248	WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
	249	is_ram == REGION_MIXED ? "mixed" : "ram", res);
a95c90f1 DW	250	error = -ENXIO;
a95c90f1 DW	251	goto err_array;
41e94a85 CH	252	}
41e94a85 CH	253
4b94ffdc	254	pgmap->dev = dev;
4b94ffdc	255
bcfa4b72 MW	256	error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
bcfa4b72 MW	257	PHYS_PFN(res->end), pgmap, GFP_KERNEL));
9476df7d	258	if (error)
bcfa4b72	259	goto err_array;
9476df7d	260
41e94a85 CH	261	nid = dev_to_node(dev);
41e94a85 CH	262	if (nid < 0)
7eff93b7	263	nid = numa_mem_id();
41e94a85	264
7cc7867f DW	265	error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0,
7cc7867f DW	266	resource_size(res));
9049771f DW	267	if (error)
	268	goto err_pfn_remap;
	269
f931ab47	270	mem_hotplug_begin();
69324b8f DW	271
	272	/*
	273	* For device private memory we call add_pages() as we only need to
	274	* allocate and initialize struct page for the device memory. More-
	275	* over the device memory is un-accessible thus we do not want to
	276	* create a linear mapping for the memory like arch_add_memory()
	277	* would do.
	278	*
	279	* For all other device memory types, which are accessible by
	280	* the CPU, we do want the linear mapping and thus use
	281	* arch_add_memory().
	282	*/
	283	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
7cc7867f DW	284	error = add_pages(nid, PHYS_PFN(res->start),
7cc7867f DW	285	PHYS_PFN(resource_size(res)), &restrictions);
69324b8f	286	} else {
7cc7867f	287	error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
69324b8f DW	288	if (error) {
	289	mem_hotplug_done();
	290	goto err_kasan;
	291	}
	292
7cc7867f	293	error = arch_add_memory(nid, res->start, resource_size(res),
940519f0	294	&restrictions);
69324b8f DW	295	}
	296
	297	if (!error) {
	298	struct zone *zone;
	299
	300	zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
7cc7867f DW	301	move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
7cc7867f DW	302	PHYS_PFN(resource_size(res)), restrictions.altmap);
0207df4f AR	303	}
0207df4f AR	304
f931ab47	305	mem_hotplug_done();
9476df7d DW	306	if (error)
9476df7d DW	307	goto err_add_memory;
41e94a85	308
966cf44f AD	309	/*
	310	* Initialization of the pages has been deferred until now in order
	311	* to allow us to do the work while not holding the hotplug lock.
	312	*/
	313	memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
7cc7867f DW	314	PHYS_PFN(res->start),
7cc7867f DW	315	PHYS_PFN(resource_size(res)), pgmap);
966cf44f	316	percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
e8d51348	317
a95c90f1 DW	318	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
	319	pgmap);
	320	if (error)
	321	return ERR_PTR(error);
e8d51348	322
41e94a85	323	return __va(res->start);
9476df7d DW	324
9476df7d DW	325	err_add_memory:
7cc7867f	326	kasan_remove_zero_shadow(__va(res->start), resource_size(res));
0207df4f	327	err_kasan:
7cc7867f	328	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
9049771f	329	err_pfn_remap:
bcfa4b72 MW	330	pgmap_array_delete(res);
bcfa4b72 MW	331	err_array:
24917f6b CH	332	dev_pagemap_kill(pgmap);
24917f6b CH	333	dev_pagemap_cleanup(pgmap);
9476df7d	334	return ERR_PTR(error);
41e94a85	335	}
808153e1	336	EXPORT_SYMBOL_GPL(devm_memremap_pages);
4b94ffdc	337
2e3f139e DW	338	void devm_memunmap_pages(struct device dev, struct dev_pagemap pgmap)
	339	{
	340	devm_release_action(dev, devm_memremap_pages_release, pgmap);
	341	}
	342	EXPORT_SYMBOL_GPL(devm_memunmap_pages);
	343
4b94ffdc DW	344	unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
	345	{
	346	/* number of pfns from base where pfn_to_page() is valid */
514caf23 CH	347	if (altmap)
	348	return altmap->reserve + altmap->free;
	349	return 0;
4b94ffdc DW	350	}
	351
	352	void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
	353	{
	354	altmap->alloc -= nr_pfns;
	355	}
	356
0822acb8 CH	357	/**
	358	* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
	359	* @pfn: page frame number to lookup page_map
	360	* @pgmap: optional known pgmap that already has a reference
	361	*
832d7aa0 CH	362	* If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
832d7aa0 CH	363	* is non-NULL but does not cover @pfn the reference to it will be released.
0822acb8 CH	364	*/
	365	struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
	366	struct dev_pagemap *pgmap)
	367	{
0822acb8 CH	368	resource_size_t phys = PFN_PHYS(pfn);
	369
	370	/*
832d7aa0	371	* In the cached case we're already holding a live reference.
0822acb8	372	*/
832d7aa0	373	if (pgmap) {
e7744aa2	374	if (phys >= pgmap->res.start && phys <= pgmap->res.end)
832d7aa0 CH	375	return pgmap;
832d7aa0 CH	376	put_dev_pagemap(pgmap);
0822acb8 CH	377	}
	378
	379	/* fall back to slow path lookup */
	380	rcu_read_lock();
bcfa4b72	381	pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
0822acb8 CH	382	if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
	383	pgmap = NULL;
	384	rcu_read_unlock();
	385
	386	return pgmap;
	387	}
e7638488	388	EXPORT_SYMBOL_GPL(get_dev_pagemap);
7b2d55d2	389
e7638488	390	#ifdef CONFIG_DEV_PAGEMAP_OPS
e7638488	391	void __put_devmap_managed_page(struct page *page)
7b2d55d2 JG	392	{
	393	int count = page_ref_dec_return(page);
	394
	395	/*
	396	* If refcount is 1 then page is freed and refcount is stable as nobody
	397	* holds a reference on the page.
	398	*/
	399	if (count == 1) {
	400	/* Clear Active bit in case of parallel mark_page_accessed */
	401	__ClearPageActive(page);
	402	__ClearPageWaiters(page);
	403
c733a828	404	mem_cgroup_uncharge(page);
7b2d55d2	405
7ab0ad0e RC	406	/*
	407	* When a device_private page is freed, the page->mapping field
	408	* may still contain a (stale) mapping value. For example, the
	409	* lower bits of page->mapping may still identify the page as
	410	* an anonymous page. Ultimately, this entire field is just
	411	* stale and wrong, and it will cause errors if not cleared.
	412	* One example is:
	413	*
	414	* migrate_vma_pages()
	415	* migrate_vma_insert_page()
	416	* page_add_new_anon_rmap()
	417	* __page_set_anon_rmap()
	418	* ...checks page->mapping, via PageAnon(page) call,
	419	* and incorrectly concludes that the page is an
	420	* anonymous page. Therefore, it incorrectly,
	421	* silently fails to set up the new anon rmap.
	422	*
	423	* For other types of ZONE_DEVICE pages, migration is either
	424	* handled differently or not done at all, so there is no need
	425	* to clear page->mapping.
	426	*/
	427	if (is_device_private_page(page))
	428	page->mapping = NULL;
	429
80a72d0a	430	page->pgmap->ops->page_free(page);
7b2d55d2 JG	431	} else if (!count)
	432	__put_page(page);
	433	}
31c5bda3	434	EXPORT_SYMBOL(__put_devmap_managed_page);
e7638488	435	#endif /* CONFIG_DEV_PAGEMAP_OPS */