1
2
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/swapops.h>
11#include <linux/types.h>
12#include <linux/wait_bit.h>
13#include <linux/xarray.h>
14
15static DEFINE_XARRAY(pgmap_array);
16#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
17#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
18
19#ifdef CONFIG_DEV_PAGEMAP_OPS
20DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
21EXPORT_SYMBOL(devmap_managed_key);
22static atomic_t devmap_managed_enable;
23
24static 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
30static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
31{
32 if (!pgmap->ops || !pgmap->ops->page_free) {
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
42static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
43{
44 return -EINVAL;
45}
46#endif
47
48static void pgmap_array_delete(struct resource *res)
49{
50 xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
51 NULL, GFP_KERNEL);
52 synchronize_rcu();
53}
54
55static unsigned long pfn_first(struct dev_pagemap *pgmap)
56{
57 return PHYS_PFN(pgmap->res.start) +
58 vmem_altmap_offset(pgmap_altmap(pgmap));
59}
60
61static unsigned long pfn_end(struct dev_pagemap *pgmap)
62{
63 const struct resource *res = &pgmap->res;
64
65 return (res->start + resource_size(res)) >> PAGE_SHIFT;
66}
67
68static unsigned long pfn_next(unsigned long pfn)
69{
70 if (pfn % 1024 == 0)
71 cond_resched();
72 return pfn + 1;
73}
74
75#define for_each_device_pfn(pfn, map) \
76 for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
77
78static 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
86static 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 }
94
95
96
97
98 if (pgmap->ref == &pgmap->internal_ref)
99 pgmap->ref = NULL;
100}
101
102static void devm_memremap_pages_release(void *data)
103{
104 struct dev_pagemap *pgmap = data;
105 struct device *dev = pgmap->dev;
106 struct resource *res = &pgmap->res;
107 unsigned long pfn;
108 int nid;
109
110 dev_pagemap_kill(pgmap);
111 for_each_device_pfn(pfn, pgmap)
112 put_page(pfn_to_page(pfn));
113 dev_pagemap_cleanup(pgmap);
114
115
116 nid = page_to_nid(pfn_to_page(PHYS_PFN(res->start)));
117
118 mem_hotplug_begin();
119 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
120 pfn = PHYS_PFN(res->start);
121 __remove_pages(page_zone(pfn_to_page(pfn)), pfn,
122 PHYS_PFN(resource_size(res)), NULL);
123 } else {
124 arch_remove_memory(nid, res->start, resource_size(res),
125 pgmap_altmap(pgmap));
126 kasan_remove_zero_shadow(__va(res->start), resource_size(res));
127 }
128 mem_hotplug_done();
129
130 untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
131 pgmap_array_delete(res);
132 dev_WARN_ONCE(dev, pgmap->altmap.alloc,
133 "%s: failed to free all reserved pages\n", __func__);
134}
135
136static 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
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163
164void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
165{
166 struct resource *res = &pgmap->res;
167 struct dev_pagemap *conflict_pgmap;
168 struct mhp_restrictions restrictions = {
169
170
171
172 .altmap = pgmap_altmap(pgmap),
173 };
174 pgprot_t pgprot = PAGE_KERNEL;
175 int error, nid, is_ram;
176 bool need_devmap_managed = true;
177
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 }
184 if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
185 WARN(1, "Missing migrate_to_ram method\n");
186 return ERR_PTR(-EINVAL);
187 }
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:
198 need_devmap_managed = false;
199 break;
200 default:
201 WARN(1, "Invalid pgmap type %d\n", pgmap->type);
202 break;
203 }
204
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 }
220 }
221
222 if (need_devmap_managed) {
223 error = devmap_managed_enable_get(dev, pgmap);
224 if (error)
225 return ERR_PTR(error);
226 }
227
228 conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
229 if (conflict_pgmap) {
230 dev_WARN(dev, "Conflicting mapping in same section\n");
231 put_dev_pagemap(conflict_pgmap);
232 error = -ENOMEM;
233 goto err_array;
234 }
235
236 conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
237 if (conflict_pgmap) {
238 dev_WARN(dev, "Conflicting mapping in same section\n");
239 put_dev_pagemap(conflict_pgmap);
240 error = -ENOMEM;
241 goto err_array;
242 }
243
244 is_ram = region_intersects(res->start, resource_size(res),
245 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
246
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);
250 error = -ENXIO;
251 goto err_array;
252 }
253
254 pgmap->dev = dev;
255
256 error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
257 PHYS_PFN(res->end), pgmap, GFP_KERNEL));
258 if (error)
259 goto err_array;
260
261 nid = dev_to_node(dev);
262 if (nid < 0)
263 nid = numa_mem_id();
264
265 error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0,
266 resource_size(res));
267 if (error)
268 goto err_pfn_remap;
269
270 mem_hotplug_begin();
271
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281
282
283 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
284 error = add_pages(nid, PHYS_PFN(res->start),
285 PHYS_PFN(resource_size(res)), &restrictions);
286 } else {
287 error = kasan_add_zero_shadow(__va(res->start), resource_size(res));
288 if (error) {
289 mem_hotplug_done();
290 goto err_kasan;
291 }
292
293 error = arch_add_memory(nid, res->start, resource_size(res),
294 &restrictions);
295 }
296
297 if (!error) {
298 struct zone *zone;
299
300 zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
301 move_pfn_range_to_zone(zone, PHYS_PFN(res->start),
302 PHYS_PFN(resource_size(res)), restrictions.altmap);
303 }
304
305 mem_hotplug_done();
306 if (error)
307 goto err_add_memory;
308
309
310
311
312
313 memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
314 PHYS_PFN(res->start),
315 PHYS_PFN(resource_size(res)), pgmap);
316 percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
317
318 error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
319 pgmap);
320 if (error)
321 return ERR_PTR(error);
322
323 return __va(res->start);
324
325 err_add_memory:
326 kasan_remove_zero_shadow(__va(res->start), resource_size(res));
327 err_kasan:
328 untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
329 err_pfn_remap:
330 pgmap_array_delete(res);
331 err_array:
332 dev_pagemap_kill(pgmap);
333 dev_pagemap_cleanup(pgmap);
334 return ERR_PTR(error);
335}
336EXPORT_SYMBOL_GPL(devm_memremap_pages);
337
338void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
339{
340 devm_release_action(dev, devm_memremap_pages_release, pgmap);
341}
342EXPORT_SYMBOL_GPL(devm_memunmap_pages);
343
344unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
345{
346
347 if (altmap)
348 return altmap->reserve + altmap->free;
349 return 0;
350}
351
352void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
353{
354 altmap->alloc -= nr_pfns;
355}
356
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362
363
364
365struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
366 struct dev_pagemap *pgmap)
367{
368 resource_size_t phys = PFN_PHYS(pfn);
369
370
371
372
373 if (pgmap) {
374 if (phys >= pgmap->res.start && phys <= pgmap->res.end)
375 return pgmap;
376 put_dev_pagemap(pgmap);
377 }
378
379
380 rcu_read_lock();
381 pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
382 if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
383 pgmap = NULL;
384 rcu_read_unlock();
385
386 return pgmap;
387}
388EXPORT_SYMBOL_GPL(get_dev_pagemap);
389
390#ifdef CONFIG_DEV_PAGEMAP_OPS
391void __put_devmap_managed_page(struct page *page)
392{
393 int count = page_ref_dec_return(page);
394
395
396
397
398
399 if (count == 1) {
400
401 __ClearPageActive(page);
402 __ClearPageWaiters(page);
403
404 mem_cgroup_uncharge(page);
405
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426
427 if (is_device_private_page(page))
428 page->mapping = NULL;
429
430 page->pgmap->ops->page_free(page);
431 } else if (!count)
432 __put_page(page);
433}
434EXPORT_SYMBOL(__put_devmap_managed_page);
435#endif
436