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(struct dev_pagemap
*pgmap
)
46 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
||
47 pgmap
->type
== MEMORY_DEVICE_FS_DAX
)
48 static_branch_dec(&devmap_managed_key
);
51 static void devmap_managed_enable_get(struct dev_pagemap
*pgmap
)
53 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
||
54 pgmap
->type
== MEMORY_DEVICE_FS_DAX
)
55 static_branch_inc(&devmap_managed_key
);
58 static void devmap_managed_enable_get(struct dev_pagemap
*pgmap
)
61 static void devmap_managed_enable_put(struct dev_pagemap
*pgmap
)
64 #endif /* CONFIG_DEV_PAGEMAP_OPS */
66 static void pgmap_array_delete(struct range
*range
)
68 xa_store_range(&pgmap_array
, PHYS_PFN(range
->start
), PHYS_PFN(range
->end
),
73 static unsigned long pfn_first(struct dev_pagemap
*pgmap
, int range_id
)
75 struct range
*range
= &pgmap
->ranges
[range_id
];
76 unsigned long pfn
= PHYS_PFN(range
->start
);
80 return pfn
+ vmem_altmap_offset(pgmap_altmap(pgmap
));
83 bool pgmap_pfn_valid(struct dev_pagemap
*pgmap
, unsigned long pfn
)
87 for (i
= 0; i
< pgmap
->nr_range
; i
++) {
88 struct range
*range
= &pgmap
->ranges
[i
];
90 if (pfn
>= PHYS_PFN(range
->start
) &&
91 pfn
<= PHYS_PFN(range
->end
))
92 return pfn
>= pfn_first(pgmap
, i
);
98 static unsigned long pfn_end(struct dev_pagemap
*pgmap
, int range_id
)
100 const struct range
*range
= &pgmap
->ranges
[range_id
];
102 return (range
->start
+ range_len(range
)) >> PAGE_SHIFT
;
105 static unsigned long pfn_next(unsigned long pfn
)
112 #define for_each_device_pfn(pfn, map, i) \
113 for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn))
115 static void dev_pagemap_kill(struct dev_pagemap
*pgmap
)
117 if (pgmap
->ops
&& pgmap
->ops
->kill
)
118 pgmap
->ops
->kill(pgmap
);
120 percpu_ref_kill(pgmap
->ref
);
123 static void dev_pagemap_cleanup(struct dev_pagemap
*pgmap
)
125 if (pgmap
->ops
&& pgmap
->ops
->cleanup
) {
126 pgmap
->ops
->cleanup(pgmap
);
128 wait_for_completion(&pgmap
->done
);
129 percpu_ref_exit(pgmap
->ref
);
132 * Undo the pgmap ref assignment for the internal case as the
133 * caller may re-enable the same pgmap.
135 if (pgmap
->ref
== &pgmap
->internal_ref
)
139 static void pageunmap_range(struct dev_pagemap
*pgmap
, int range_id
)
141 struct range
*range
= &pgmap
->ranges
[range_id
];
142 struct page
*first_page
;
145 /* make sure to access a memmap that was actually initialized */
146 first_page
= pfn_to_page(pfn_first(pgmap
, range_id
));
148 /* pages are dead and unused, undo the arch mapping */
149 nid
= page_to_nid(first_page
);
152 remove_pfn_range_from_zone(page_zone(first_page
), PHYS_PFN(range
->start
),
153 PHYS_PFN(range_len(range
)));
154 if (pgmap
->type
== MEMORY_DEVICE_PRIVATE
) {
155 __remove_pages(PHYS_PFN(range
->start
),
156 PHYS_PFN(range_len(range
)), NULL
);
158 arch_remove_memory(nid
, range
->start
, range_len(range
),
159 pgmap_altmap(pgmap
));
160 kasan_remove_zero_shadow(__va(range
->start
), range_len(range
));
164 untrack_pfn(NULL
, PHYS_PFN(range
->start
), range_len(range
));
165 pgmap_array_delete(range
);
168 void memunmap_pages(struct dev_pagemap
*pgmap
)
173 dev_pagemap_kill(pgmap
);
174 for (i
= 0; i
< pgmap
->nr_range
; i
++)
175 for_each_device_pfn(pfn
, pgmap
, i
)
176 put_page(pfn_to_page(pfn
));
177 dev_pagemap_cleanup(pgmap
);
179 for (i
= 0; i
< pgmap
->nr_range
; i
++)
180 pageunmap_range(pgmap
, i
);
182 WARN_ONCE(pgmap
->altmap
.alloc
, "failed to free all reserved pages\n");
183 devmap_managed_enable_put(pgmap
);
185 EXPORT_SYMBOL_GPL(memunmap_pages
);
187 static void devm_memremap_pages_release(void *data
)
189 memunmap_pages(data
);
192 static void dev_pagemap_percpu_release(struct percpu_ref
*ref
)
194 struct dev_pagemap
*pgmap
=
195 container_of(ref
, struct dev_pagemap
, internal_ref
);
197 complete(&pgmap
->done
);
200 static int pagemap_range(struct dev_pagemap
*pgmap
, struct mhp_params
*params
,
201 int range_id
, int nid
)
203 const bool is_private
= pgmap
->type
== MEMORY_DEVICE_PRIVATE
;
204 struct range
*range
= &pgmap
->ranges
[range_id
];
205 struct dev_pagemap
*conflict_pgmap
;
208 if (WARN_ONCE(pgmap_altmap(pgmap
) && range_id
> 0,
209 "altmap not supported for multiple ranges\n"))
212 conflict_pgmap
= get_dev_pagemap(PHYS_PFN(range
->start
), NULL
);
213 if (conflict_pgmap
) {
214 WARN(1, "Conflicting mapping in same section\n");
215 put_dev_pagemap(conflict_pgmap
);
219 conflict_pgmap
= get_dev_pagemap(PHYS_PFN(range
->end
), NULL
);
220 if (conflict_pgmap
) {
221 WARN(1, "Conflicting mapping in same section\n");
222 put_dev_pagemap(conflict_pgmap
);
226 is_ram
= region_intersects(range
->start
, range_len(range
),
227 IORESOURCE_SYSTEM_RAM
, IORES_DESC_NONE
);
229 if (is_ram
!= REGION_DISJOINT
) {
230 WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",
231 is_ram
== REGION_MIXED
? "mixed" : "ram",
232 range
->start
, range
->end
);
236 error
= xa_err(xa_store_range(&pgmap_array
, PHYS_PFN(range
->start
),
237 PHYS_PFN(range
->end
), pgmap
, GFP_KERNEL
));
244 error
= track_pfn_remap(NULL
, ¶ms
->pgprot
, PHYS_PFN(range
->start
), 0,
249 if (!mhp_range_allowed(range
->start
, range_len(range
), !is_private
)) {
257 * For device private memory we call add_pages() as we only need to
258 * allocate and initialize struct page for the device memory. More-
259 * over the device memory is un-accessible thus we do not want to
260 * create a linear mapping for the memory like arch_add_memory()
263 * For all other device memory types, which are accessible by
264 * the CPU, we do want the linear mapping and thus use
268 error
= add_pages(nid
, PHYS_PFN(range
->start
),
269 PHYS_PFN(range_len(range
)), params
);
271 error
= kasan_add_zero_shadow(__va(range
->start
), range_len(range
));
277 error
= arch_add_memory(nid
, range
->start
, range_len(range
),
284 zone
= &NODE_DATA(nid
)->node_zones
[ZONE_DEVICE
];
285 move_pfn_range_to_zone(zone
, PHYS_PFN(range
->start
),
286 PHYS_PFN(range_len(range
)), params
->altmap
,
295 * Initialization of the pages has been deferred until now in order
296 * to allow us to do the work while not holding the hotplug lock.
298 memmap_init_zone_device(&NODE_DATA(nid
)->node_zones
[ZONE_DEVICE
],
299 PHYS_PFN(range
->start
),
300 PHYS_PFN(range_len(range
)), pgmap
);
301 percpu_ref_get_many(pgmap
->ref
, pfn_end(pgmap
, range_id
)
302 - pfn_first(pgmap
, range_id
));
306 kasan_remove_zero_shadow(__va(range
->start
), range_len(range
));
308 untrack_pfn(NULL
, PHYS_PFN(range
->start
), range_len(range
));
310 pgmap_array_delete(range
);
316 * Not device managed version of dev_memremap_pages, undone by
317 * memunmap_pages(). Please use dev_memremap_pages if you have a struct
320 void *memremap_pages(struct dev_pagemap
*pgmap
, int nid
)
322 struct mhp_params params
= {
323 .altmap
= pgmap_altmap(pgmap
),
324 .pgprot
= PAGE_KERNEL
,
326 const int nr_range
= pgmap
->nr_range
;
329 if (WARN_ONCE(!nr_range
, "nr_range must be specified\n"))
330 return ERR_PTR(-EINVAL
);
332 switch (pgmap
->type
) {
333 case MEMORY_DEVICE_PRIVATE
:
334 if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE
)) {
335 WARN(1, "Device private memory not supported\n");
336 return ERR_PTR(-EINVAL
);
338 if (!pgmap
->ops
|| !pgmap
->ops
->migrate_to_ram
) {
339 WARN(1, "Missing migrate_to_ram method\n");
340 return ERR_PTR(-EINVAL
);
342 if (!pgmap
->ops
->page_free
) {
343 WARN(1, "Missing page_free method\n");
344 return ERR_PTR(-EINVAL
);
347 WARN(1, "Missing owner\n");
348 return ERR_PTR(-EINVAL
);
351 case MEMORY_DEVICE_FS_DAX
:
352 if (!IS_ENABLED(CONFIG_ZONE_DEVICE
) ||
353 IS_ENABLED(CONFIG_FS_DAX_LIMITED
)) {
354 WARN(1, "File system DAX not supported\n");
355 return ERR_PTR(-EINVAL
);
358 case MEMORY_DEVICE_GENERIC
:
360 case MEMORY_DEVICE_PCI_P2PDMA
:
361 params
.pgprot
= pgprot_noncached(params
.pgprot
);
364 WARN(1, "Invalid pgmap type %d\n", pgmap
->type
);
369 if (pgmap
->ops
&& (pgmap
->ops
->kill
|| pgmap
->ops
->cleanup
))
370 return ERR_PTR(-EINVAL
);
372 init_completion(&pgmap
->done
);
373 error
= percpu_ref_init(&pgmap
->internal_ref
,
374 dev_pagemap_percpu_release
, 0, GFP_KERNEL
);
376 return ERR_PTR(error
);
377 pgmap
->ref
= &pgmap
->internal_ref
;
379 if (!pgmap
->ops
|| !pgmap
->ops
->kill
|| !pgmap
->ops
->cleanup
) {
380 WARN(1, "Missing reference count teardown definition\n");
381 return ERR_PTR(-EINVAL
);
385 devmap_managed_enable_get(pgmap
);
388 * Clear the pgmap nr_range as it will be incremented for each
389 * successfully processed range. This communicates how many
390 * regions to unwind in the abort case.
394 for (i
= 0; i
< nr_range
; i
++) {
395 error
= pagemap_range(pgmap
, ¶ms
, i
, nid
);
402 memunmap_pages(pgmap
);
403 pgmap
->nr_range
= nr_range
;
404 return ERR_PTR(error
);
407 return __va(pgmap
->ranges
[0].start
);
409 EXPORT_SYMBOL_GPL(memremap_pages
);
412 * devm_memremap_pages - remap and provide memmap backing for the given resource
413 * @dev: hosting device for @res
414 * @pgmap: pointer to a struct dev_pagemap
417 * 1/ At a minimum the res and type members of @pgmap must be initialized
418 * by the caller before passing it to this function
420 * 2/ The altmap field may optionally be initialized, in which case
421 * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
423 * 3/ The ref field may optionally be provided, in which pgmap->ref must be
424 * 'live' on entry and will be killed and reaped at
425 * devm_memremap_pages_release() time, or if this routine fails.
427 * 4/ range is expected to be a host memory range that could feasibly be
428 * treated as a "System RAM" range, i.e. not a device mmio range, but
429 * this is not enforced.
431 void *devm_memremap_pages(struct device
*dev
, struct dev_pagemap
*pgmap
)
436 ret
= memremap_pages(pgmap
, dev_to_node(dev
));
440 error
= devm_add_action_or_reset(dev
, devm_memremap_pages_release
,
443 return ERR_PTR(error
);
446 EXPORT_SYMBOL_GPL(devm_memremap_pages
);
448 void devm_memunmap_pages(struct device
*dev
, struct dev_pagemap
*pgmap
)
450 devm_release_action(dev
, devm_memremap_pages_release
, pgmap
);
452 EXPORT_SYMBOL_GPL(devm_memunmap_pages
);
454 unsigned long vmem_altmap_offset(struct vmem_altmap
*altmap
)
456 /* number of pfns from base where pfn_to_page() is valid */
458 return altmap
->reserve
+ altmap
->free
;
462 void vmem_altmap_free(struct vmem_altmap
*altmap
, unsigned long nr_pfns
)
464 altmap
->alloc
-= nr_pfns
;
468 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
469 * @pfn: page frame number to lookup page_map
470 * @pgmap: optional known pgmap that already has a reference
472 * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
473 * is non-NULL but does not cover @pfn the reference to it will be released.
475 struct dev_pagemap
*get_dev_pagemap(unsigned long pfn
,
476 struct dev_pagemap
*pgmap
)
478 resource_size_t phys
= PFN_PHYS(pfn
);
481 * In the cached case we're already holding a live reference.
484 if (phys
>= pgmap
->range
.start
&& phys
<= pgmap
->range
.end
)
486 put_dev_pagemap(pgmap
);
489 /* fall back to slow path lookup */
491 pgmap
= xa_load(&pgmap_array
, PHYS_PFN(phys
));
492 if (pgmap
&& !percpu_ref_tryget_live(pgmap
->ref
))
498 EXPORT_SYMBOL_GPL(get_dev_pagemap
);
500 #ifdef CONFIG_DEV_PAGEMAP_OPS
501 void free_devmap_managed_page(struct page
*page
)
503 /* notify page idle for dax */
504 if (!is_device_private_page(page
)) {
505 wake_up_var(&page
->_refcount
);
509 __ClearPageWaiters(page
);
511 mem_cgroup_uncharge(page
);
514 * When a device_private page is freed, the page->mapping field
515 * may still contain a (stale) mapping value. For example, the
516 * lower bits of page->mapping may still identify the page as an
517 * anonymous page. Ultimately, this entire field is just stale
518 * and wrong, and it will cause errors if not cleared. One
521 * migrate_vma_pages()
522 * migrate_vma_insert_page()
523 * page_add_new_anon_rmap()
524 * __page_set_anon_rmap()
525 * ...checks page->mapping, via PageAnon(page) call,
526 * and incorrectly concludes that the page is an
527 * anonymous page. Therefore, it incorrectly,
528 * silently fails to set up the new anon rmap.
530 * For other types of ZONE_DEVICE pages, migration is either
531 * handled differently or not done at all, so there is no need
532 * to clear page->mapping.
534 page
->mapping
= NULL
;
535 page
->pgmap
->ops
->page_free(page
);
537 #endif /* CONFIG_DEV_PAGEMAP_OPS */