1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright(c) 2015 Intel Corporation. All rights reserved. */
3 #include <linux/device.h>
5 #include <linux/kasan.h>
6 #include <linux/memory_hotplug.h>
8 #include <linux/pfn_t.h>
9 #include <linux/swap.h>
10 #include <linux/mmzone.h>
11 #include <linux/swapops.h>
12 #include <linux/types.h>
13 #include <linux/wait_bit.h>
14 #include <linux/xarray.h>
16 static DEFINE_XARRAY(pgmap_array
);
19 * The memremap() and memremap_pages() interfaces are alternately used
20 * to map persistent memory namespaces. These interfaces place different
21 * constraints on the alignment and size of the mapping (namespace).
22 * memremap() can map individual PAGE_SIZE pages. memremap_pages() can
23 * only map subsections (2MB), and at least one architecture (PowerPC)
24 * the minimum mapping granularity of memremap_pages() is 16MB.
26 * The role of memremap_compat_align() is to communicate the minimum
27 * arch supported alignment of a namespace such that it can freely
28 * switch modes without violating the arch constraint. Namely, do not
29 * allow a namespace to be PAGE_SIZE aligned since that namespace may be
30 * reconfigured into a mode that requires SUBSECTION_SIZE alignment.
32 #ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN
33 unsigned long memremap_compat_align(void)
35 return SUBSECTION_SIZE
;
37 EXPORT_SYMBOL_GPL(memremap_compat_align
);
40 #ifdef CONFIG_DEV_PAGEMAP_OPS
41 DEFINE_STATIC_KEY_FALSE(devmap_managed_key
);
42 EXPORT_SYMBOL(devmap_managed_key
);
44 static void devmap_managed_enable_put(void)
46 static_branch_dec(&devmap_managed_key
);
49 static int devmap_managed_enable_get(struct dev_pagemap
*pgmap
)
51 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
&&
52 (!pgmap
->ops
|| !pgmap
->ops
->page_free
)) {
53 WARN(1, "Missing page_free method\n");
57 static_branch_inc(&devmap_managed_key
);
61 static int devmap_managed_enable_get(struct dev_pagemap
*pgmap
)
65 static void devmap_managed_enable_put(void)
68 #endif /* CONFIG_DEV_PAGEMAP_OPS */
70 static void pgmap_array_delete(struct range
*range
)
72 xa_store_range(&pgmap_array
, PHYS_PFN(range
->start
), PHYS_PFN(range
->end
),
77 static unsigned long pfn_first(struct dev_pagemap
*pgmap
, int range_id
)
79 struct range
*range
= &pgmap
->ranges
[range_id
];
80 unsigned long pfn
= PHYS_PFN(range
->start
);
84 return pfn
+ vmem_altmap_offset(pgmap_altmap(pgmap
));
87 static unsigned long pfn_end(struct dev_pagemap
*pgmap
, int range_id
)
89 const struct range
*range
= &pgmap
->ranges
[range_id
];
91 return (range
->start
+ range_len(range
)) >> PAGE_SHIFT
;
94 static unsigned long pfn_next(unsigned long pfn
)
101 #define for_each_device_pfn(pfn, map, i) \
102 for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn))
104 static void dev_pagemap_kill(struct dev_pagemap
*pgmap
)
106 if (pgmap
->ops
&& pgmap
->ops
->kill
)
107 pgmap
->ops
->kill(pgmap
);
109 percpu_ref_kill(pgmap
->ref
);
112 static void dev_pagemap_cleanup(struct dev_pagemap
*pgmap
)
114 if (pgmap
->ops
&& pgmap
->ops
->cleanup
) {
115 pgmap
->ops
->cleanup(pgmap
);
117 wait_for_completion(&pgmap
->done
);
118 percpu_ref_exit(pgmap
->ref
);
121 * Undo the pgmap ref assignment for the internal case as the
122 * caller may re-enable the same pgmap.
124 if (pgmap
->ref
== &pgmap
->internal_ref
)
128 static void pageunmap_range(struct dev_pagemap
*pgmap
, int range_id
)
130 struct range
*range
= &pgmap
->ranges
[range_id
];
131 struct page
*first_page
;
134 /* make sure to access a memmap that was actually initialized */
135 first_page
= pfn_to_page(pfn_first(pgmap
, range_id
));
137 /* pages are dead and unused, undo the arch mapping */
138 nid
= page_to_nid(first_page
);
141 remove_pfn_range_from_zone(page_zone(first_page
), PHYS_PFN(range
->start
),
142 PHYS_PFN(range_len(range
)));
143 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
) {
144 __remove_pages(PHYS_PFN(range
->start
),
145 PHYS_PFN(range_len(range
)), NULL
);
147 arch_remove_memory(nid
, range
->start
, range_len(range
),
148 pgmap_altmap(pgmap
));
149 kasan_remove_zero_shadow(__va(range
->start
), range_len(range
));
153 untrack_pfn(NULL
, PHYS_PFN(range
->start
), range_len(range
));
154 pgmap_array_delete(range
);
157 void memunmap_pages(struct dev_pagemap
*pgmap
)
162 dev_pagemap_kill(pgmap
);
163 for (i
= 0; i
< pgmap
->nr_range
; i
++)
164 for_each_device_pfn(pfn
, pgmap
, i
)
165 put_page(pfn_to_page(pfn
));
166 dev_pagemap_cleanup(pgmap
);
168 for (i
= 0; i
< pgmap
->nr_range
; i
++)
169 pageunmap_range(pgmap
, i
);
171 WARN_ONCE(pgmap
->altmap
.alloc
, "failed to free all reserved pages\n");
172 devmap_managed_enable_put();
174 EXPORT_SYMBOL_GPL(memunmap_pages
);
176 static void devm_memremap_pages_release(void *data
)
178 memunmap_pages(data
);
181 static void dev_pagemap_percpu_release(struct percpu_ref
*ref
)
183 struct dev_pagemap
*pgmap
=
184 container_of(ref
, struct dev_pagemap
, internal_ref
);
186 complete(&pgmap
->done
);
189 static int pagemap_range(struct dev_pagemap
*pgmap
, struct mhp_params
*params
,
190 int range_id
, int nid
)
192 struct range
*range
= &pgmap
->ranges
[range_id
];
193 struct dev_pagemap
*conflict_pgmap
;
196 if (WARN_ONCE(pgmap_altmap(pgmap
) && range_id
> 0,
197 "altmap not supported for multiple ranges\n"))
200 conflict_pgmap
= get_dev_pagemap(PHYS_PFN(range
->start
), NULL
);
201 if (conflict_pgmap
) {
202 WARN(1, "Conflicting mapping in same section\n");
203 put_dev_pagemap(conflict_pgmap
);
207 conflict_pgmap
= get_dev_pagemap(PHYS_PFN(range
->end
), NULL
);
208 if (conflict_pgmap
) {
209 WARN(1, "Conflicting mapping in same section\n");
210 put_dev_pagemap(conflict_pgmap
);
214 is_ram
= region_intersects(range
->start
, range_len(range
),
215 IORESOURCE_SYSTEM_RAM
, IORES_DESC_NONE
);
217 if (is_ram
!= REGION_DISJOINT
) {
218 WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",
219 is_ram
== REGION_MIXED
? "mixed" : "ram",
220 range
->start
, range
->end
);
224 error
= xa_err(xa_store_range(&pgmap_array
, PHYS_PFN(range
->start
),
225 PHYS_PFN(range
->end
), pgmap
, GFP_KERNEL
));
232 error
= track_pfn_remap(NULL
, ¶ms
->pgprot
, PHYS_PFN(range
->start
), 0,
240 * For device private memory we call add_pages() as we only need to
241 * allocate and initialize struct page for the device memory. More-
242 * over the device memory is un-accessible thus we do not want to
243 * create a linear mapping for the memory like arch_add_memory()
246 * For all other device memory types, which are accessible by
247 * the CPU, we do want the linear mapping and thus use
250 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
) {
251 error
= add_pages(nid
, PHYS_PFN(range
->start
),
252 PHYS_PFN(range_len(range
)), params
);
254 error
= kasan_add_zero_shadow(__va(range
->start
), range_len(range
));
260 error
= arch_add_memory(nid
, range
->start
, range_len(range
),
267 zone
= &NODE_DATA(nid
)->node_zones
[ZONE_DEVICE
];
268 move_pfn_range_to_zone(zone
, PHYS_PFN(range
->start
),
269 PHYS_PFN(range_len(range
)), params
->altmap
,
278 * Initialization of the pages has been deferred until now in order
279 * to allow us to do the work while not holding the hotplug lock.
281 memmap_init_zone_device(&NODE_DATA(nid
)->node_zones
[ZONE_DEVICE
],
282 PHYS_PFN(range
->start
),
283 PHYS_PFN(range_len(range
)), pgmap
);
284 percpu_ref_get_many(pgmap
->ref
, pfn_end(pgmap
, range_id
)
285 - pfn_first(pgmap
, range_id
));
289 kasan_remove_zero_shadow(__va(range
->start
), range_len(range
));
291 untrack_pfn(NULL
, PHYS_PFN(range
->start
), range_len(range
));
293 pgmap_array_delete(range
);
299 * Not device managed version of dev_memremap_pages, undone by
300 * memunmap_pages(). Please use dev_memremap_pages if you have a struct
303 void *memremap_pages(struct dev_pagemap
*pgmap
, int nid
)
305 struct mhp_params params
= {
306 .altmap
= pgmap_altmap(pgmap
),
307 .pgprot
= PAGE_KERNEL
,
309 const int nr_range
= pgmap
->nr_range
;
310 bool need_devmap_managed
= true;
313 if (WARN_ONCE(!nr_range
, "nr_range must be specified\n"))
314 return ERR_PTR(-EINVAL
);
316 switch (pgmap
->type
) {
317 case MEMORY_DEVICE_PRIVATE
:
318 if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE
)) {
319 WARN(1, "Device private memory not supported\n");
320 return ERR_PTR(-EINVAL
);
322 if (!pgmap
->ops
|| !pgmap
->ops
->migrate_to_ram
) {
323 WARN(1, "Missing migrate_to_ram method\n");
324 return ERR_PTR(-EINVAL
);
327 WARN(1, "Missing owner\n");
328 return ERR_PTR(-EINVAL
);
331 case MEMORY_DEVICE_FS_DAX
:
332 if (!IS_ENABLED(CONFIG_ZONE_DEVICE
) ||
333 IS_ENABLED(CONFIG_FS_DAX_LIMITED
)) {
334 WARN(1, "File system DAX not supported\n");
335 return ERR_PTR(-EINVAL
);
338 case MEMORY_DEVICE_GENERIC
:
339 need_devmap_managed
= false;
341 case MEMORY_DEVICE_PCI_P2PDMA
:
342 params
.pgprot
= pgprot_noncached(params
.pgprot
);
343 need_devmap_managed
= false;
346 WARN(1, "Invalid pgmap type %d\n", pgmap
->type
);
351 if (pgmap
->ops
&& (pgmap
->ops
->kill
|| pgmap
->ops
->cleanup
))
352 return ERR_PTR(-EINVAL
);
354 init_completion(&pgmap
->done
);
355 error
= percpu_ref_init(&pgmap
->internal_ref
,
356 dev_pagemap_percpu_release
, 0, GFP_KERNEL
);
358 return ERR_PTR(error
);
359 pgmap
->ref
= &pgmap
->internal_ref
;
361 if (!pgmap
->ops
|| !pgmap
->ops
->kill
|| !pgmap
->ops
->cleanup
) {
362 WARN(1, "Missing reference count teardown definition\n");
363 return ERR_PTR(-EINVAL
);
367 if (need_devmap_managed
) {
368 error
= devmap_managed_enable_get(pgmap
);
370 return ERR_PTR(error
);
374 * Clear the pgmap nr_range as it will be incremented for each
375 * successfully processed range. This communicates how many
376 * regions to unwind in the abort case.
380 for (i
= 0; i
< nr_range
; i
++) {
381 error
= pagemap_range(pgmap
, ¶ms
, i
, nid
);
388 memunmap_pages(pgmap
);
389 pgmap
->nr_range
= nr_range
;
390 return ERR_PTR(error
);
393 return __va(pgmap
->ranges
[0].start
);
395 EXPORT_SYMBOL_GPL(memremap_pages
);
398 * devm_memremap_pages - remap and provide memmap backing for the given resource
399 * @dev: hosting device for @res
400 * @pgmap: pointer to a struct dev_pagemap
403 * 1/ At a minimum the res and type members of @pgmap must be initialized
404 * by the caller before passing it to this function
406 * 2/ The altmap field may optionally be initialized, in which case
407 * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
409 * 3/ The ref field may optionally be provided, in which pgmap->ref must be
410 * 'live' on entry and will be killed and reaped at
411 * devm_memremap_pages_release() time, or if this routine fails.
413 * 4/ range is expected to be a host memory range that could feasibly be
414 * treated as a "System RAM" range, i.e. not a device mmio range, but
415 * this is not enforced.
417 void *devm_memremap_pages(struct device
*dev
, struct dev_pagemap
*pgmap
)
422 ret
= memremap_pages(pgmap
, dev_to_node(dev
));
426 error
= devm_add_action_or_reset(dev
, devm_memremap_pages_release
,
429 return ERR_PTR(error
);
432 EXPORT_SYMBOL_GPL(devm_memremap_pages
);
434 void devm_memunmap_pages(struct device
*dev
, struct dev_pagemap
*pgmap
)
436 devm_release_action(dev
, devm_memremap_pages_release
, pgmap
);
438 EXPORT_SYMBOL_GPL(devm_memunmap_pages
);
440 unsigned long vmem_altmap_offset(struct vmem_altmap
*altmap
)
442 /* number of pfns from base where pfn_to_page() is valid */
444 return altmap
->reserve
+ altmap
->free
;
448 void vmem_altmap_free(struct vmem_altmap
*altmap
, unsigned long nr_pfns
)
450 altmap
->alloc
-= nr_pfns
;
454 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
455 * @pfn: page frame number to lookup page_map
456 * @pgmap: optional known pgmap that already has a reference
458 * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
459 * is non-NULL but does not cover @pfn the reference to it will be released.
461 struct dev_pagemap
*get_dev_pagemap(unsigned long pfn
,
462 struct dev_pagemap
*pgmap
)
464 resource_size_t phys
= PFN_PHYS(pfn
);
467 * In the cached case we're already holding a live reference.
470 if (phys
>= pgmap
->range
.start
&& phys
<= pgmap
->range
.end
)
472 put_dev_pagemap(pgmap
);
475 /* fall back to slow path lookup */
477 pgmap
= xa_load(&pgmap_array
, PHYS_PFN(phys
));
478 if (pgmap
&& !percpu_ref_tryget_live(pgmap
->ref
))
484 EXPORT_SYMBOL_GPL(get_dev_pagemap
);
486 #ifdef CONFIG_DEV_PAGEMAP_OPS
487 void free_devmap_managed_page(struct page
*page
)
489 /* notify page idle for dax */
490 if (!is_device_private_page(page
)) {
491 wake_up_var(&page
->_refcount
);
495 __ClearPageWaiters(page
);
497 mem_cgroup_uncharge(page
);
500 * When a device_private page is freed, the page->mapping field
501 * may still contain a (stale) mapping value. For example, the
502 * lower bits of page->mapping may still identify the page as an
503 * anonymous page. Ultimately, this entire field is just stale
504 * and wrong, and it will cause errors if not cleared. One
507 * migrate_vma_pages()
508 * migrate_vma_insert_page()
509 * page_add_new_anon_rmap()
510 * __page_set_anon_rmap()
511 * ...checks page->mapping, via PageAnon(page) call,
512 * and incorrectly concludes that the page is an
513 * anonymous page. Therefore, it incorrectly,
514 * silently fails to set up the new anon rmap.
516 * For other types of ZONE_DEVICE pages, migration is either
517 * handled differently or not done at all, so there is no need
518 * to clear page->mapping.
520 page
->mapping
= NULL
;
521 page
->pgmap
->ops
->page_free(page
);
523 #endif /* CONFIG_DEV_PAGEMAP_OPS */