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1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
3#include <linux/device.h>
4#include <linux/io.h>
5#include <linux/kasan.h>
6#include <linux/memory_hotplug.h>
7#include <linux/mm.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>
15
16static DEFINE_XARRAY(pgmap_array);
17
18/*
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.
25 *
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.
31 */
32#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN
33unsigned long memremap_compat_align(void)
34{
35 return SUBSECTION_SIZE;
36}
37EXPORT_SYMBOL_GPL(memremap_compat_align);
38#endif
39
40#ifdef CONFIG_DEV_PAGEMAP_OPS
41DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
42EXPORT_SYMBOL(devmap_managed_key);
43static atomic_t devmap_managed_enable;
44
45static void devmap_managed_enable_put(void)
46{
47 if (atomic_dec_and_test(&devmap_managed_enable))
48 static_branch_disable(&devmap_managed_key);
49}
50
51static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
52{
53 if (pgmap->type == MEMORY_DEVICE_PRIVATE &&
54 (!pgmap->ops || !pgmap->ops->page_free)) {
55 WARN(1, "Missing page_free method\n");
56 return -EINVAL;
57 }
58
59 if (atomic_inc_return(&devmap_managed_enable) == 1)
60 static_branch_enable(&devmap_managed_key);
61 return 0;
62}
63#else
64static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
65{
66 return -EINVAL;
67}
68static void devmap_managed_enable_put(void)
69{
70}
71#endif /* CONFIG_DEV_PAGEMAP_OPS */
72
73static void pgmap_array_delete(struct resource *res)
74{
75 xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
76 NULL, GFP_KERNEL);
77 synchronize_rcu();
78}
79
80static unsigned long pfn_first(struct dev_pagemap *pgmap)
81{
82 return PHYS_PFN(pgmap->res.start) +
83 vmem_altmap_offset(pgmap_altmap(pgmap));
84}
85
86static unsigned long pfn_end(struct dev_pagemap *pgmap)
87{
88 const struct resource *res = &pgmap->res;
89
90 return (res->start + resource_size(res)) >> PAGE_SHIFT;
91}
92
93static unsigned long pfn_next(unsigned long pfn)
94{
95 if (pfn % 1024 == 0)
96 cond_resched();
97 return pfn + 1;
98}
99
100#define for_each_device_pfn(pfn, map) \
101 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
102
103static void dev_pagemap_kill(struct dev_pagemap *pgmap)
104{
105 if (pgmap->ops && pgmap->ops->kill)
106 pgmap->ops->kill(pgmap);
107 else
108 percpu_ref_kill(pgmap->ref);
109}
110
111static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
112{
113 if (pgmap->ops && pgmap->ops->cleanup) {
114 pgmap->ops->cleanup(pgmap);
115 } else {
116 wait_for_completion(&pgmap->done);
117 percpu_ref_exit(pgmap->ref);
118 }
119 /*
120 * Undo the pgmap ref assignment for the internal case as the
121 * caller may re-enable the same pgmap.
122 */
123 if (pgmap->ref == &pgmap->internal_ref)
124 pgmap->ref = NULL;
125}
126
127void memunmap_pages(struct dev_pagemap *pgmap)
128{
129 struct resource *res = &pgmap->res;
130 struct page *first_page;
131 unsigned long pfn;
132 int nid;
133
134 dev_pagemap_kill(pgmap);
135 for_each_device_pfn(pfn, pgmap)
136 put_page(pfn_to_page(pfn));
137 dev_pagemap_cleanup(pgmap);
138
139 /* make sure to access a memmap that was actually initialized */
140 first_page = pfn_to_page(pfn_first(pgmap));
141
142 /* pages are dead and unused, undo the arch mapping */
143 nid = page_to_nid(first_page);
144
145 mem_hotplug_begin();
146 remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(res->start),
147 PHYS_PFN(resource_size(res)));
148 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
149 __remove_pages(PHYS_PFN(res->start),
150 PHYS_PFN(resource_size(res)), NULL);
151 } else {
152 arch_remove_memory(nid, res->start, resource_size(res),
153 pgmap_altmap(pgmap));
154 kasan_remove_zero_shadow(__va(res->start), resource_size(res));
155 }
156 mem_hotplug_done();
157
158 untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
159 pgmap_array_delete(res);
160 WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
161 devmap_managed_enable_put();
162}
163EXPORT_SYMBOL_GPL(memunmap_pages);
164
165static void devm_memremap_pages_release(void *data)
166{
167 memunmap_pages(data);
168}
169
170static void dev_pagemap_percpu_release(struct percpu_ref *ref)
171{
172 struct dev_pagemap *pgmap =
173 container_of(ref, struct dev_pagemap, internal_ref);
174
175 complete(&pgmap->done);
176}
177
178/*
179 * Not device managed version of dev_memremap_pages, undone by
180 * memunmap_pages(). Please use dev_memremap_pages if you have a struct
181 * device available.
182 */
183void *memremap_pages(struct dev_pagemap *pgmap, int nid)
184{
185 struct resource *res = &pgmap->res;
186 struct dev_pagemap *conflict_pgmap;
187 struct mhp_params params = {
188 /*
189 * We do not want any optional features only our own memmap
190 */
191 .altmap = pgmap_altmap(pgmap),
192 .pgprot = PAGE_KERNEL,
193 };
194 int error, is_ram;
195 bool need_devmap_managed = true;
196
197 switch (pgmap->type) {
198 case MEMORY_DEVICE_PRIVATE:
199 if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
200 WARN(1, "Device private memory not supported\n");
201 return ERR_PTR(-EINVAL);
202 }
203 if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
204 WARN(1, "Missing migrate_to_ram method\n");
205 return ERR_PTR(-EINVAL);
206 }
207 if (!pgmap->owner) {
208 WARN(1, "Missing owner\n");
209 return ERR_PTR(-EINVAL);
210 }
211 break;
212 case MEMORY_DEVICE_FS_DAX:
213 if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
214 IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
215 WARN(1, "File system DAX not supported\n");
216 return ERR_PTR(-EINVAL);
217 }
218 break;
219 case MEMORY_DEVICE_GENERIC:
220 need_devmap_managed = false;
221 break;
222 case MEMORY_DEVICE_PCI_P2PDMA:
223 params.pgprot = pgprot_noncached(params.pgprot);
224 need_devmap_managed = false;
225 break;
226 default:
227 WARN(1, "Invalid pgmap type %d\n", pgmap->type);
228 break;
229 }
230
231 if (!pgmap->ref) {
232 if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
233 return ERR_PTR(-EINVAL);
234
235 init_completion(&pgmap->done);
236 error = percpu_ref_init(&pgmap->internal_ref,
237 dev_pagemap_percpu_release, 0, GFP_KERNEL);
238 if (error)
239 return ERR_PTR(error);
240 pgmap->ref = &pgmap->internal_ref;
241 } else {
242 if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
243 WARN(1, "Missing reference count teardown definition\n");
244 return ERR_PTR(-EINVAL);
245 }
246 }
247
248 if (need_devmap_managed) {
249 error = devmap_managed_enable_get(pgmap);
250 if (error)
251 return ERR_PTR(error);
252 }
253
254 conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
255 if (conflict_pgmap) {
256 WARN(1, "Conflicting mapping in same section\n");
257 put_dev_pagemap(conflict_pgmap);
258 error = -ENOMEM;
259 goto err_array;
260 }
261
262 conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
263 if (conflict_pgmap) {
264 WARN(1, "Conflicting mapping in same section\n");
265 put_dev_pagemap(conflict_pgmap);
266 error = -ENOMEM;
267 goto err_array;
268 }
269
270 is_ram = region_intersects(res->start, resource_size(res),
271 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
272
273 if (is_ram != REGION_DISJOINT) {
274 WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
275 is_ram == REGION_MIXED ? "mixed" : "ram", res);
276 error = -ENXIO;
277 goto err_array;
278 }
279
280 error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
281 PHYS_PFN(res->end), pgmap, GFP_KERNEL));
282 if (error)
283 goto err_array;
284
285 if (nid < 0)
286 nid = numa_mem_id();
287
288 error = track_pfn_remap(NULL, ¶ms.pgprot, PHYS_PFN(res->start),
289 0, resource_size(res));
290 if (error)
291 goto err_pfn_remap;
292
293 mem_hotplug_begin();
294
295 /*
296 * For device private memory we call add_pages() as we only need to
297 * allocate and initialize struct page for the device memory. More-
298 * over the device memory is un-accessible thus we do not want to
299 * create a linear mapping for the memory like arch_add_memory()
300 * would do.
301 *
302 * For all other device memory types, which are accessible by
303 * the CPU, we do want the linear mapping and thus use
304 * arch_add_memory().
305 */
306 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
307 error = add_pages(nid, PHYS_PFN(res->start),
308 PHYS_PFN(resource_size(res)), ¶ms);
309 } else {
310 error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
311 if (error) {
312 mem_hotplug_done();
313 goto err_kasan;
314 }
315
316 error = arch_add_memory(nid, res->start, resource_size(res),
317 ¶ms);
318 }
319
320 if (!error) {
321 struct zone *zone;
322
323 zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
324 move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
325 PHYS_PFN(resource_size(res)), params.altmap);
326 }
327
328 mem_hotplug_done();
329 if (error)
330 goto err_add_memory;
331
332 /*
333 * Initialization of the pages has been deferred until now in order
334 * to allow us to do the work while not holding the hotplug lock.
335 */
336 memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
337 PHYS_PFN(res->start),
338 PHYS_PFN(resource_size(res)), pgmap);
339 percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
340 return __va(res->start);
341
342 err_add_memory:
343 kasan_remove_zero_shadow(__va(res->start), resource_size(res));
344 err_kasan:
345 untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
346 err_pfn_remap:
347 pgmap_array_delete(res);
348 err_array:
349 dev_pagemap_kill(pgmap);
350 dev_pagemap_cleanup(pgmap);
351 devmap_managed_enable_put();
352 return ERR_PTR(error);
353}
354EXPORT_SYMBOL_GPL(memremap_pages);
355
356/**
357 * devm_memremap_pages - remap and provide memmap backing for the given resource
358 * @dev: hosting device for @res
359 * @pgmap: pointer to a struct dev_pagemap
360 *
361 * Notes:
362 * 1/ At a minimum the res and type members of @pgmap must be initialized
363 * by the caller before passing it to this function
364 *
365 * 2/ The altmap field may optionally be initialized, in which case
366 * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
367 *
368 * 3/ The ref field may optionally be provided, in which pgmap->ref must be
369 * 'live' on entry and will be killed and reaped at
370 * devm_memremap_pages_release() time, or if this routine fails.
371 *
372 * 4/ res is expected to be a host memory range that could feasibly be
373 * treated as a "System RAM" range, i.e. not a device mmio range, but
374 * this is not enforced.
375 */
376void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
377{
378 int error;
379 void *ret;
380
381 ret = memremap_pages(pgmap, dev_to_node(dev));
382 if (IS_ERR(ret))
383 return ret;
384
385 error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
386 pgmap);
387 if (error)
388 return ERR_PTR(error);
389 return ret;
390}
391EXPORT_SYMBOL_GPL(devm_memremap_pages);
392
393void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
394{
395 devm_release_action(dev, devm_memremap_pages_release, pgmap);
396}
397EXPORT_SYMBOL_GPL(devm_memunmap_pages);
398
399unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
400{
401 /* number of pfns from base where pfn_to_page() is valid */
402 if (altmap)
403 return altmap->reserve + altmap->free;
404 return 0;
405}
406
407void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
408{
409 altmap->alloc -= nr_pfns;
410}
411
412/**
413 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
414 * @pfn: page frame number to lookup page_map
415 * @pgmap: optional known pgmap that already has a reference
416 *
417 * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
418 * is non-NULL but does not cover @pfn the reference to it will be released.
419 */
420struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
421 struct dev_pagemap *pgmap)
422{
423 resource_size_t phys = PFN_PHYS(pfn);
424
425 /*
426 * In the cached case we're already holding a live reference.
427 */
428 if (pgmap) {
429 if (phys >= pgmap->res.start && phys <= pgmap->res.end)
430 return pgmap;
431 put_dev_pagemap(pgmap);
432 }
433
434 /* fall back to slow path lookup */
435 rcu_read_lock();
436 pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
437 if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
438 pgmap = NULL;
439 rcu_read_unlock();
440
441 return pgmap;
442}
443EXPORT_SYMBOL_GPL(get_dev_pagemap);
444
445#ifdef CONFIG_DEV_PAGEMAP_OPS
446void free_devmap_managed_page(struct page *page)
447{
448 /* notify page idle for dax */
449 if (!is_device_private_page(page)) {
450 wake_up_var(&page->_refcount);
451 return;
452 }
453
454 /* Clear Active bit in case of parallel mark_page_accessed */
455 __ClearPageActive(page);
456 __ClearPageWaiters(page);
457
458 mem_cgroup_uncharge(page);
459
460 /*
461 * When a device_private page is freed, the page->mapping field
462 * may still contain a (stale) mapping value. For example, the
463 * lower bits of page->mapping may still identify the page as an
464 * anonymous page. Ultimately, this entire field is just stale
465 * and wrong, and it will cause errors if not cleared. One
466 * example is:
467 *
468 * migrate_vma_pages()
469 * migrate_vma_insert_page()
470 * page_add_new_anon_rmap()
471 * __page_set_anon_rmap()
472 * ...checks page->mapping, via PageAnon(page) call,
473 * and incorrectly concludes that the page is an
474 * anonymous page. Therefore, it incorrectly,
475 * silently fails to set up the new anon rmap.
476 *
477 * For other types of ZONE_DEVICE pages, migration is either
478 * handled differently or not done at all, so there is no need
479 * to clear page->mapping.
480 */
481 page->mapping = NULL;
482 page->pgmap->ops->page_free(page);
483}
484#endif /* CONFIG_DEV_PAGEMAP_OPS */
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
3#include <linux/device.h>
4#include <linux/io.h>
5#include <linux/kasan.h>
6#include <linux/memory_hotplug.h>
7#include <linux/memremap.h>
8#include <linux/pfn_t.h>
9#include <linux/swap.h>
10#include <linux/mm.h>
11#include <linux/mmzone.h>
12#include <linux/swapops.h>
13#include <linux/types.h>
14#include <linux/wait_bit.h>
15#include <linux/xarray.h>
16#include "internal.h"
17
18static DEFINE_XARRAY(pgmap_array);
19
20/*
21 * The memremap() and memremap_pages() interfaces are alternately used
22 * to map persistent memory namespaces. These interfaces place different
23 * constraints on the alignment and size of the mapping (namespace).
24 * memremap() can map individual PAGE_SIZE pages. memremap_pages() can
25 * only map subsections (2MB), and at least one architecture (PowerPC)
26 * the minimum mapping granularity of memremap_pages() is 16MB.
27 *
28 * The role of memremap_compat_align() is to communicate the minimum
29 * arch supported alignment of a namespace such that it can freely
30 * switch modes without violating the arch constraint. Namely, do not
31 * allow a namespace to be PAGE_SIZE aligned since that namespace may be
32 * reconfigured into a mode that requires SUBSECTION_SIZE alignment.
33 */
34#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN
35unsigned long memremap_compat_align(void)
36{
37 return SUBSECTION_SIZE;
38}
39EXPORT_SYMBOL_GPL(memremap_compat_align);
40#endif
41
42#ifdef CONFIG_FS_DAX
43DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
44EXPORT_SYMBOL(devmap_managed_key);
45
46static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
47{
48 if (pgmap->type == MEMORY_DEVICE_FS_DAX)
49 static_branch_dec(&devmap_managed_key);
50}
51
52static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
53{
54 if (pgmap->type == MEMORY_DEVICE_FS_DAX)
55 static_branch_inc(&devmap_managed_key);
56}
57#else
58static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
59{
60}
61static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
62{
63}
64#endif /* CONFIG_FS_DAX */
65
66static void pgmap_array_delete(struct range *range)
67{
68 xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->end),
69 NULL, GFP_KERNEL);
70 synchronize_rcu();
71}
72
73static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id)
74{
75 struct range *range = &pgmap->ranges[range_id];
76 unsigned long pfn = PHYS_PFN(range->start);
77
78 if (range_id)
79 return pfn;
80 return pfn + vmem_altmap_offset(pgmap_altmap(pgmap));
81}
82
83bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
84{
85 int i;
86
87 for (i = 0; i < pgmap->nr_range; i++) {
88 struct range *range = &pgmap->ranges[i];
89
90 if (pfn >= PHYS_PFN(range->start) &&
91 pfn <= PHYS_PFN(range->end))
92 return pfn >= pfn_first(pgmap, i);
93 }
94
95 return false;
96}
97
98static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id)
99{
100 const struct range *range = &pgmap->ranges[range_id];
101
102 return (range->start + range_len(range)) >> PAGE_SHIFT;
103}
104
105static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id)
106{
107 return (pfn_end(pgmap, range_id) -
108 pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift;
109}
110
111static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
112{
113 struct range *range = &pgmap->ranges[range_id];
114 struct page *first_page;
115
116 /* make sure to access a memmap that was actually initialized */
117 first_page = pfn_to_page(pfn_first(pgmap, range_id));
118
119 /* pages are dead and unused, undo the arch mapping */
120 mem_hotplug_begin();
121 remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start),
122 PHYS_PFN(range_len(range)));
123 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
124 __remove_pages(PHYS_PFN(range->start),
125 PHYS_PFN(range_len(range)), NULL);
126 } else {
127 arch_remove_memory(range->start, range_len(range),
128 pgmap_altmap(pgmap));
129 kasan_remove_zero_shadow(__va(range->start), range_len(range));
130 }
131 mem_hotplug_done();
132
133 untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
134 pgmap_array_delete(range);
135}
136
137void memunmap_pages(struct dev_pagemap *pgmap)
138{
139 int i;
140
141 percpu_ref_kill(&pgmap->ref);
142 if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
143 pgmap->type != MEMORY_DEVICE_COHERENT)
144 for (i = 0; i < pgmap->nr_range; i++)
145 percpu_ref_put_many(&pgmap->ref, pfn_len(pgmap, i));
146
147 wait_for_completion(&pgmap->done);
148
149 for (i = 0; i < pgmap->nr_range; i++)
150 pageunmap_range(pgmap, i);
151 percpu_ref_exit(&pgmap->ref);
152
153 WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
154 devmap_managed_enable_put(pgmap);
155}
156EXPORT_SYMBOL_GPL(memunmap_pages);
157
158static void devm_memremap_pages_release(void *data)
159{
160 memunmap_pages(data);
161}
162
163static void dev_pagemap_percpu_release(struct percpu_ref *ref)
164{
165 struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);
166
167 complete(&pgmap->done);
168}
169
170static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
171 int range_id, int nid)
172{
173 const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE;
174 struct range *range = &pgmap->ranges[range_id];
175 struct dev_pagemap *conflict_pgmap;
176 int error, is_ram;
177
178 if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0,
179 "altmap not supported for multiple ranges\n"))
180 return -EINVAL;
181
182 conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL);
183 if (conflict_pgmap) {
184 WARN(1, "Conflicting mapping in same section\n");
185 put_dev_pagemap(conflict_pgmap);
186 return -ENOMEM;
187 }
188
189 conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL);
190 if (conflict_pgmap) {
191 WARN(1, "Conflicting mapping in same section\n");
192 put_dev_pagemap(conflict_pgmap);
193 return -ENOMEM;
194 }
195
196 is_ram = region_intersects(range->start, range_len(range),
197 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
198
199 if (is_ram != REGION_DISJOINT) {
200 WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",
201 is_ram == REGION_MIXED ? "mixed" : "ram",
202 range->start, range->end);
203 return -ENXIO;
204 }
205
206 error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start),
207 PHYS_PFN(range->end), pgmap, GFP_KERNEL));
208 if (error)
209 return error;
210
211 if (nid < 0)
212 nid = numa_mem_id();
213
214 error = track_pfn_remap(NULL, ¶ms->pgprot, PHYS_PFN(range->start), 0,
215 range_len(range));
216 if (error)
217 goto err_pfn_remap;
218
219 if (!mhp_range_allowed(range->start, range_len(range), !is_private)) {
220 error = -EINVAL;
221 goto err_kasan;
222 }
223
224 mem_hotplug_begin();
225
226 /*
227 * For device private memory we call add_pages() as we only need to
228 * allocate and initialize struct page for the device memory. More-
229 * over the device memory is un-accessible thus we do not want to
230 * create a linear mapping for the memory like arch_add_memory()
231 * would do.
232 *
233 * For all other device memory types, which are accessible by
234 * the CPU, we do want the linear mapping and thus use
235 * arch_add_memory().
236 */
237 if (is_private) {
238 error = add_pages(nid, PHYS_PFN(range->start),
239 PHYS_PFN(range_len(range)), params);
240 } else {
241 error = kasan_add_zero_shadow(__va(range->start), range_len(range));
242 if (error) {
243 mem_hotplug_done();
244 goto err_kasan;
245 }
246
247 error = arch_add_memory(nid, range->start, range_len(range),
248 params);
249 }
250
251 if (!error) {
252 struct zone *zone;
253
254 zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
255 move_pfn_range_to_zone(zone, PHYS_PFN(range->start),
256 PHYS_PFN(range_len(range)), params->altmap,
257 MIGRATE_MOVABLE);
258 }
259
260 mem_hotplug_done();
261 if (error)
262 goto err_add_memory;
263
264 /*
265 * Initialization of the pages has been deferred until now in order
266 * to allow us to do the work while not holding the hotplug lock.
267 */
268 memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
269 PHYS_PFN(range->start),
270 PHYS_PFN(range_len(range)), pgmap);
271 if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
272 pgmap->type != MEMORY_DEVICE_COHERENT)
273 percpu_ref_get_many(&pgmap->ref, pfn_len(pgmap, range_id));
274 return 0;
275
276err_add_memory:
277 if (!is_private)
278 kasan_remove_zero_shadow(__va(range->start), range_len(range));
279err_kasan:
280 untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
281err_pfn_remap:
282 pgmap_array_delete(range);
283 return error;
284}
285
286
287/*
288 * Not device managed version of devm_memremap_pages, undone by
289 * memunmap_pages(). Please use devm_memremap_pages if you have a struct
290 * device available.
291 */
292void *memremap_pages(struct dev_pagemap *pgmap, int nid)
293{
294 struct mhp_params params = {
295 .altmap = pgmap_altmap(pgmap),
296 .pgmap = pgmap,
297 .pgprot = PAGE_KERNEL,
298 };
299 const int nr_range = pgmap->nr_range;
300 int error, i;
301
302 if (WARN_ONCE(!nr_range, "nr_range must be specified\n"))
303 return ERR_PTR(-EINVAL);
304
305 switch (pgmap->type) {
306 case MEMORY_DEVICE_PRIVATE:
307 if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
308 WARN(1, "Device private memory not supported\n");
309 return ERR_PTR(-EINVAL);
310 }
311 if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
312 WARN(1, "Missing migrate_to_ram method\n");
313 return ERR_PTR(-EINVAL);
314 }
315 if (!pgmap->ops->page_free) {
316 WARN(1, "Missing page_free method\n");
317 return ERR_PTR(-EINVAL);
318 }
319 if (!pgmap->owner) {
320 WARN(1, "Missing owner\n");
321 return ERR_PTR(-EINVAL);
322 }
323 break;
324 case MEMORY_DEVICE_COHERENT:
325 if (!pgmap->ops->page_free) {
326 WARN(1, "Missing page_free method\n");
327 return ERR_PTR(-EINVAL);
328 }
329 if (!pgmap->owner) {
330 WARN(1, "Missing owner\n");
331 return ERR_PTR(-EINVAL);
332 }
333 break;
334 case MEMORY_DEVICE_FS_DAX:
335 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
336 WARN(1, "File system DAX not supported\n");
337 return ERR_PTR(-EINVAL);
338 }
339 params.pgprot = pgprot_decrypted(params.pgprot);
340 break;
341 case MEMORY_DEVICE_GENERIC:
342 break;
343 case MEMORY_DEVICE_PCI_P2PDMA:
344 params.pgprot = pgprot_noncached(params.pgprot);
345 break;
346 default:
347 WARN(1, "Invalid pgmap type %d\n", pgmap->type);
348 break;
349 }
350
351 init_completion(&pgmap->done);
352 error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,
353 GFP_KERNEL);
354 if (error)
355 return ERR_PTR(error);
356
357 devmap_managed_enable_get(pgmap);
358
359 /*
360 * Clear the pgmap nr_range as it will be incremented for each
361 * successfully processed range. This communicates how many
362 * regions to unwind in the abort case.
363 */
364 pgmap->nr_range = 0;
365 error = 0;
366 for (i = 0; i < nr_range; i++) {
367 error = pagemap_range(pgmap, ¶ms, i, nid);
368 if (error)
369 break;
370 pgmap->nr_range++;
371 }
372
373 if (i < nr_range) {
374 memunmap_pages(pgmap);
375 pgmap->nr_range = nr_range;
376 return ERR_PTR(error);
377 }
378
379 return __va(pgmap->ranges[0].start);
380}
381EXPORT_SYMBOL_GPL(memremap_pages);
382
383/**
384 * devm_memremap_pages - remap and provide memmap backing for the given resource
385 * @dev: hosting device for @res
386 * @pgmap: pointer to a struct dev_pagemap
387 *
388 * Notes:
389 * 1/ At a minimum the range and type members of @pgmap must be initialized
390 * by the caller before passing it to this function
391 *
392 * 2/ The altmap field may optionally be initialized, in which case
393 * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
394 *
395 * 3/ The ref field may optionally be provided, in which pgmap->ref must be
396 * 'live' on entry and will be killed and reaped at
397 * devm_memremap_pages_release() time, or if this routine fails.
398 *
399 * 4/ range is expected to be a host memory range that could feasibly be
400 * treated as a "System RAM" range, i.e. not a device mmio range, but
401 * this is not enforced.
402 */
403void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
404{
405 int error;
406 void *ret;
407
408 ret = memremap_pages(pgmap, dev_to_node(dev));
409 if (IS_ERR(ret))
410 return ret;
411
412 error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
413 pgmap);
414 if (error)
415 return ERR_PTR(error);
416 return ret;
417}
418EXPORT_SYMBOL_GPL(devm_memremap_pages);
419
420void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
421{
422 devm_release_action(dev, devm_memremap_pages_release, pgmap);
423}
424EXPORT_SYMBOL_GPL(devm_memunmap_pages);
425
426/**
427 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
428 * @pfn: page frame number to lookup page_map
429 * @pgmap: optional known pgmap that already has a reference
430 *
431 * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
432 * is non-NULL but does not cover @pfn the reference to it will be released.
433 */
434struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
435 struct dev_pagemap *pgmap)
436{
437 resource_size_t phys = PFN_PHYS(pfn);
438
439 /*
440 * In the cached case we're already holding a live reference.
441 */
442 if (pgmap) {
443 if (phys >= pgmap->range.start && phys <= pgmap->range.end)
444 return pgmap;
445 put_dev_pagemap(pgmap);
446 }
447
448 /* fall back to slow path lookup */
449 rcu_read_lock();
450 pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
451 if (pgmap && !percpu_ref_tryget_live_rcu(&pgmap->ref))
452 pgmap = NULL;
453 rcu_read_unlock();
454
455 return pgmap;
456}
457EXPORT_SYMBOL_GPL(get_dev_pagemap);
458
459void free_zone_device_page(struct page *page)
460{
461 if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
462 return;
463
464 mem_cgroup_uncharge(page_folio(page));
465
466 /*
467 * Note: we don't expect anonymous compound pages yet. Once supported
468 * and we could PTE-map them similar to THP, we'd have to clear
469 * PG_anon_exclusive on all tail pages.
470 */
471 VM_BUG_ON_PAGE(PageAnon(page) && PageCompound(page), page);
472 if (PageAnon(page))
473 __ClearPageAnonExclusive(page);
474
475 /*
476 * When a device managed page is freed, the folio->mapping field
477 * may still contain a (stale) mapping value. For example, the
478 * lower bits of folio->mapping may still identify the folio as an
479 * anonymous folio. Ultimately, this entire field is just stale
480 * and wrong, and it will cause errors if not cleared.
481 *
482 * For other types of ZONE_DEVICE pages, migration is either
483 * handled differently or not done at all, so there is no need
484 * to clear page->mapping.
485 */
486 page->mapping = NULL;
487 page->pgmap->ops->page_free(page);
488
489 if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
490 page->pgmap->type != MEMORY_DEVICE_COHERENT)
491 /*
492 * Reset the page count to 1 to prepare for handing out the page
493 * again.
494 */
495 set_page_count(page, 1);
496 else
497 put_dev_pagemap(page->pgmap);
498}
499
500void zone_device_page_init(struct page *page)
501{
502 /*
503 * Drivers shouldn't be allocating pages after calling
504 * memunmap_pages().
505 */
506 WARN_ON_ONCE(!percpu_ref_tryget_live(&page->pgmap->ref));
507 set_page_count(page, 1);
508 lock_page(page);
509}
510EXPORT_SYMBOL_GPL(zone_device_page_init);
511
512#ifdef CONFIG_FS_DAX
513bool __put_devmap_managed_page_refs(struct page *page, int refs)
514{
515 if (page->pgmap->type != MEMORY_DEVICE_FS_DAX)
516 return false;
517
518 /*
519 * fsdax page refcounts are 1-based, rather than 0-based: if
520 * refcount is 1, then the page is free and the refcount is
521 * stable because nobody holds a reference on the page.
522 */
523 if (page_ref_sub_return(page, refs) == 1)
524 wake_up_var(&page->_refcount);
525 return true;
526}
527EXPORT_SYMBOL(__put_devmap_managed_page_refs);
528#endif /* CONFIG_FS_DAX */