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5981690d DW |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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> |
8 | #include <linux/pfn_t.h> | |
5042db43 JG |
9 | #include <linux/swap.h> |
10 | #include <linux/swapops.h> | |
bcfa4b72 | 11 | #include <linux/types.h> |
e7638488 | 12 | #include <linux/wait_bit.h> |
bcfa4b72 | 13 | #include <linux/xarray.h> |
063a7d1d | 14 | #include <linux/hmm.h> |
92281dee | 15 | |
bcfa4b72 | 16 | static DEFINE_XARRAY(pgmap_array); |
9476df7d DW |
17 | #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) |
18 | #define SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
19 | ||
5042db43 | 20 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) |
2b740303 | 21 | vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, |
5042db43 JG |
22 | unsigned long addr, |
23 | swp_entry_t entry, | |
24 | unsigned int flags, | |
25 | pmd_t *pmdp) | |
26 | { | |
27 | struct page *page = device_private_entry_to_page(entry); | |
063a7d1d DW |
28 | struct hmm_devmem *devmem; |
29 | ||
30 | devmem = container_of(page->pgmap, typeof(*devmem), pagemap); | |
5042db43 JG |
31 | |
32 | /* | |
33 | * The page_fault() callback must migrate page back to system memory | |
34 | * so that CPU can access it. This might fail for various reasons | |
35 | * (device issue, device was unsafely unplugged, ...). When such | |
36 | * error conditions happen, the callback must return VM_FAULT_SIGBUS. | |
37 | * | |
38 | * Note that because memory cgroup charges are accounted to the device | |
39 | * memory, this should never fail because of memory restrictions (but | |
40 | * allocation of regular system page might still fail because we are | |
41 | * out of memory). | |
42 | * | |
43 | * There is a more in-depth description of what that callback can and | |
44 | * cannot do, in include/linux/memremap.h | |
45 | */ | |
063a7d1d | 46 | return devmem->page_fault(vma, addr, page, flags, pmdp); |
5042db43 | 47 | } |
5042db43 JG |
48 | #endif /* CONFIG_DEVICE_PRIVATE */ |
49 | ||
bcfa4b72 | 50 | static void pgmap_array_delete(struct resource *res) |
ab1b597e | 51 | { |
bcfa4b72 MW |
52 | xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), |
53 | NULL, GFP_KERNEL); | |
ab1b597e | 54 | synchronize_rcu(); |
9476df7d DW |
55 | } |
56 | ||
e7744aa2 | 57 | static unsigned long pfn_first(struct dev_pagemap *pgmap) |
5c2c2587 | 58 | { |
e7744aa2 LG |
59 | const struct resource *res = &pgmap->res; |
60 | struct vmem_altmap *altmap = &pgmap->altmap; | |
5c2c2587 DW |
61 | unsigned long pfn; |
62 | ||
63 | pfn = res->start >> PAGE_SHIFT; | |
e7744aa2 | 64 | if (pgmap->altmap_valid) |
5c2c2587 DW |
65 | pfn += vmem_altmap_offset(altmap); |
66 | return pfn; | |
67 | } | |
68 | ||
e7744aa2 | 69 | static unsigned long pfn_end(struct dev_pagemap *pgmap) |
5c2c2587 | 70 | { |
e7744aa2 | 71 | const struct resource *res = &pgmap->res; |
5c2c2587 DW |
72 | |
73 | return (res->start + resource_size(res)) >> PAGE_SHIFT; | |
74 | } | |
75 | ||
949b9325 DW |
76 | static unsigned long pfn_next(unsigned long pfn) |
77 | { | |
78 | if (pfn % 1024 == 0) | |
79 | cond_resched(); | |
80 | return pfn + 1; | |
81 | } | |
82 | ||
5c2c2587 | 83 | #define for_each_device_pfn(pfn, map) \ |
949b9325 | 84 | for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) |
5c2c2587 | 85 | |
e8d51348 | 86 | static void devm_memremap_pages_release(void *data) |
41e94a85 | 87 | { |
e7744aa2 | 88 | struct dev_pagemap *pgmap = data; |
e8d51348 | 89 | struct device *dev = pgmap->dev; |
e7744aa2 | 90 | struct resource *res = &pgmap->res; |
9476df7d | 91 | resource_size_t align_start, align_size; |
71389703 | 92 | unsigned long pfn; |
2c2a5af6 | 93 | int nid; |
71389703 | 94 | |
a95c90f1 | 95 | pgmap->kill(pgmap->ref); |
e7744aa2 | 96 | for_each_device_pfn(pfn, pgmap) |
71389703 | 97 | put_page(pfn_to_page(pfn)); |
50f44ee7 | 98 | pgmap->cleanup(pgmap->ref); |
9476df7d | 99 | |
41e94a85 | 100 | /* pages are dead and unused, undo the arch mapping */ |
9476df7d | 101 | align_start = res->start & ~(SECTION_SIZE - 1); |
10a0cd6e JS |
102 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) |
103 | - align_start; | |
b5d24fda | 104 | |
2c2a5af6 OS |
105 | nid = page_to_nid(pfn_to_page(align_start >> PAGE_SHIFT)); |
106 | ||
f931ab47 | 107 | mem_hotplug_begin(); |
69324b8f DW |
108 | if (pgmap->type == MEMORY_DEVICE_PRIVATE) { |
109 | pfn = align_start >> PAGE_SHIFT; | |
110 | __remove_pages(page_zone(pfn_to_page(pfn)), pfn, | |
111 | align_size >> PAGE_SHIFT, NULL); | |
112 | } else { | |
2c2a5af6 | 113 | arch_remove_memory(nid, align_start, align_size, |
69324b8f DW |
114 | pgmap->altmap_valid ? &pgmap->altmap : NULL); |
115 | kasan_remove_zero_shadow(__va(align_start), align_size); | |
116 | } | |
f931ab47 | 117 | mem_hotplug_done(); |
b5d24fda | 118 | |
9049771f | 119 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
bcfa4b72 | 120 | pgmap_array_delete(res); |
e7744aa2 LG |
121 | dev_WARN_ONCE(dev, pgmap->altmap.alloc, |
122 | "%s: failed to free all reserved pages\n", __func__); | |
9476df7d DW |
123 | } |
124 | ||
4b94ffdc DW |
125 | /** |
126 | * devm_memremap_pages - remap and provide memmap backing for the given resource | |
127 | * @dev: hosting device for @res | |
a95c90f1 | 128 | * @pgmap: pointer to a struct dev_pagemap |
4b94ffdc | 129 | * |
5c2c2587 | 130 | * Notes: |
e8d51348 CH |
131 | * 1/ At a minimum the res, ref and type members of @pgmap must be initialized |
132 | * by the caller before passing it to this function | |
133 | * | |
134 | * 2/ The altmap field may optionally be initialized, in which case altmap_valid | |
135 | * must be set to true | |
136 | * | |
50f44ee7 DW |
137 | * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped |
138 | * at devm_memremap_pages_release() time, or if this routine fails. | |
5c2c2587 | 139 | * |
e8d51348 | 140 | * 4/ res is expected to be a host memory range that could feasibly be |
5c2c2587 DW |
141 | * treated as a "System RAM" range, i.e. not a device mmio range, but |
142 | * this is not enforced. | |
4b94ffdc | 143 | */ |
e8d51348 | 144 | void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) |
41e94a85 | 145 | { |
ab1b597e | 146 | resource_size_t align_start, align_size, align_end; |
e8d51348 CH |
147 | struct vmem_altmap *altmap = pgmap->altmap_valid ? |
148 | &pgmap->altmap : NULL; | |
949b9325 | 149 | struct resource *res = &pgmap->res; |
966cf44f | 150 | struct dev_pagemap *conflict_pgmap; |
940519f0 MH |
151 | struct mhp_restrictions restrictions = { |
152 | /* | |
153 | * We do not want any optional features only our own memmap | |
154 | */ | |
155 | .altmap = altmap, | |
156 | }; | |
9049771f | 157 | pgprot_t pgprot = PAGE_KERNEL; |
949b9325 | 158 | int error, nid, is_ram; |
5f29a77c | 159 | |
50f44ee7 DW |
160 | if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) { |
161 | WARN(1, "Missing reference count teardown definition\n"); | |
a95c90f1 | 162 | return ERR_PTR(-EINVAL); |
50f44ee7 | 163 | } |
a95c90f1 | 164 | |
5f29a77c DW |
165 | align_start = res->start & ~(SECTION_SIZE - 1); |
166 | align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) | |
167 | - align_start; | |
15d36fec DJ |
168 | align_end = align_start + align_size - 1; |
169 | ||
170 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL); | |
171 | if (conflict_pgmap) { | |
172 | dev_WARN(dev, "Conflicting mapping in same section\n"); | |
173 | put_dev_pagemap(conflict_pgmap); | |
50f44ee7 DW |
174 | error = -ENOMEM; |
175 | goto err_array; | |
15d36fec DJ |
176 | } |
177 | ||
178 | conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL); | |
179 | if (conflict_pgmap) { | |
180 | dev_WARN(dev, "Conflicting mapping in same section\n"); | |
181 | put_dev_pagemap(conflict_pgmap); | |
50f44ee7 DW |
182 | error = -ENOMEM; |
183 | goto err_array; | |
15d36fec DJ |
184 | } |
185 | ||
d37a14bb LT |
186 | is_ram = region_intersects(align_start, align_size, |
187 | IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); | |
41e94a85 | 188 | |
06489cfb DW |
189 | if (is_ram != REGION_DISJOINT) { |
190 | WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, | |
191 | is_ram == REGION_MIXED ? "mixed" : "ram", res); | |
a95c90f1 DW |
192 | error = -ENXIO; |
193 | goto err_array; | |
41e94a85 CH |
194 | } |
195 | ||
4b94ffdc | 196 | pgmap->dev = dev; |
4b94ffdc | 197 | |
bcfa4b72 MW |
198 | error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), |
199 | PHYS_PFN(res->end), pgmap, GFP_KERNEL)); | |
9476df7d | 200 | if (error) |
bcfa4b72 | 201 | goto err_array; |
9476df7d | 202 | |
41e94a85 CH |
203 | nid = dev_to_node(dev); |
204 | if (nid < 0) | |
7eff93b7 | 205 | nid = numa_mem_id(); |
41e94a85 | 206 | |
9049771f DW |
207 | error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0, |
208 | align_size); | |
209 | if (error) | |
210 | goto err_pfn_remap; | |
211 | ||
f931ab47 | 212 | mem_hotplug_begin(); |
69324b8f DW |
213 | |
214 | /* | |
215 | * For device private memory we call add_pages() as we only need to | |
216 | * allocate and initialize struct page for the device memory. More- | |
217 | * over the device memory is un-accessible thus we do not want to | |
218 | * create a linear mapping for the memory like arch_add_memory() | |
219 | * would do. | |
220 | * | |
221 | * For all other device memory types, which are accessible by | |
222 | * the CPU, we do want the linear mapping and thus use | |
223 | * arch_add_memory(). | |
224 | */ | |
225 | if (pgmap->type == MEMORY_DEVICE_PRIVATE) { | |
226 | error = add_pages(nid, align_start >> PAGE_SHIFT, | |
940519f0 | 227 | align_size >> PAGE_SHIFT, &restrictions); |
69324b8f DW |
228 | } else { |
229 | error = kasan_add_zero_shadow(__va(align_start), align_size); | |
230 | if (error) { | |
231 | mem_hotplug_done(); | |
232 | goto err_kasan; | |
233 | } | |
234 | ||
940519f0 MH |
235 | error = arch_add_memory(nid, align_start, align_size, |
236 | &restrictions); | |
69324b8f DW |
237 | } |
238 | ||
239 | if (!error) { | |
240 | struct zone *zone; | |
241 | ||
242 | zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; | |
243 | move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT, | |
244 | align_size >> PAGE_SHIFT, altmap); | |
0207df4f AR |
245 | } |
246 | ||
f931ab47 | 247 | mem_hotplug_done(); |
9476df7d DW |
248 | if (error) |
249 | goto err_add_memory; | |
41e94a85 | 250 | |
966cf44f AD |
251 | /* |
252 | * Initialization of the pages has been deferred until now in order | |
253 | * to allow us to do the work while not holding the hotplug lock. | |
254 | */ | |
255 | memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
256 | align_start >> PAGE_SHIFT, | |
257 | align_size >> PAGE_SHIFT, pgmap); | |
258 | percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); | |
e8d51348 | 259 | |
a95c90f1 DW |
260 | error = devm_add_action_or_reset(dev, devm_memremap_pages_release, |
261 | pgmap); | |
262 | if (error) | |
263 | return ERR_PTR(error); | |
e8d51348 | 264 | |
41e94a85 | 265 | return __va(res->start); |
9476df7d DW |
266 | |
267 | err_add_memory: | |
0207df4f AR |
268 | kasan_remove_zero_shadow(__va(align_start), align_size); |
269 | err_kasan: | |
9049771f DW |
270 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); |
271 | err_pfn_remap: | |
bcfa4b72 MW |
272 | pgmap_array_delete(res); |
273 | err_array: | |
a95c90f1 | 274 | pgmap->kill(pgmap->ref); |
50f44ee7 DW |
275 | pgmap->cleanup(pgmap->ref); |
276 | ||
9476df7d | 277 | return ERR_PTR(error); |
41e94a85 | 278 | } |
808153e1 | 279 | EXPORT_SYMBOL_GPL(devm_memremap_pages); |
4b94ffdc | 280 | |
2e3f139e DW |
281 | void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) |
282 | { | |
283 | devm_release_action(dev, devm_memremap_pages_release, pgmap); | |
284 | } | |
285 | EXPORT_SYMBOL_GPL(devm_memunmap_pages); | |
286 | ||
4b94ffdc DW |
287 | unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) |
288 | { | |
289 | /* number of pfns from base where pfn_to_page() is valid */ | |
290 | return altmap->reserve + altmap->free; | |
291 | } | |
292 | ||
293 | void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) | |
294 | { | |
295 | altmap->alloc -= nr_pfns; | |
296 | } | |
297 | ||
0822acb8 CH |
298 | /** |
299 | * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn | |
300 | * @pfn: page frame number to lookup page_map | |
301 | * @pgmap: optional known pgmap that already has a reference | |
302 | * | |
832d7aa0 CH |
303 | * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap |
304 | * is non-NULL but does not cover @pfn the reference to it will be released. | |
0822acb8 CH |
305 | */ |
306 | struct dev_pagemap *get_dev_pagemap(unsigned long pfn, | |
307 | struct dev_pagemap *pgmap) | |
308 | { | |
0822acb8 CH |
309 | resource_size_t phys = PFN_PHYS(pfn); |
310 | ||
311 | /* | |
832d7aa0 | 312 | * In the cached case we're already holding a live reference. |
0822acb8 | 313 | */ |
832d7aa0 | 314 | if (pgmap) { |
e7744aa2 | 315 | if (phys >= pgmap->res.start && phys <= pgmap->res.end) |
832d7aa0 CH |
316 | return pgmap; |
317 | put_dev_pagemap(pgmap); | |
0822acb8 CH |
318 | } |
319 | ||
320 | /* fall back to slow path lookup */ | |
321 | rcu_read_lock(); | |
bcfa4b72 | 322 | pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); |
0822acb8 CH |
323 | if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) |
324 | pgmap = NULL; | |
325 | rcu_read_unlock(); | |
326 | ||
327 | return pgmap; | |
328 | } | |
e7638488 | 329 | EXPORT_SYMBOL_GPL(get_dev_pagemap); |
7b2d55d2 | 330 | |
e7638488 DW |
331 | #ifdef CONFIG_DEV_PAGEMAP_OPS |
332 | DEFINE_STATIC_KEY_FALSE(devmap_managed_key); | |
31c5bda3 | 333 | EXPORT_SYMBOL(devmap_managed_key); |
e7638488 DW |
334 | static atomic_t devmap_enable; |
335 | ||
336 | /* | |
337 | * Toggle the static key for ->page_free() callbacks when dev_pagemap | |
338 | * pages go idle. | |
339 | */ | |
340 | void dev_pagemap_get_ops(void) | |
341 | { | |
342 | if (atomic_inc_return(&devmap_enable) == 1) | |
343 | static_branch_enable(&devmap_managed_key); | |
344 | } | |
345 | EXPORT_SYMBOL_GPL(dev_pagemap_get_ops); | |
346 | ||
347 | void dev_pagemap_put_ops(void) | |
348 | { | |
349 | if (atomic_dec_and_test(&devmap_enable)) | |
350 | static_branch_disable(&devmap_managed_key); | |
351 | } | |
352 | EXPORT_SYMBOL_GPL(dev_pagemap_put_ops); | |
353 | ||
354 | void __put_devmap_managed_page(struct page *page) | |
7b2d55d2 JG |
355 | { |
356 | int count = page_ref_dec_return(page); | |
357 | ||
358 | /* | |
359 | * If refcount is 1 then page is freed and refcount is stable as nobody | |
360 | * holds a reference on the page. | |
361 | */ | |
362 | if (count == 1) { | |
363 | /* Clear Active bit in case of parallel mark_page_accessed */ | |
364 | __ClearPageActive(page); | |
365 | __ClearPageWaiters(page); | |
366 | ||
c733a828 | 367 | mem_cgroup_uncharge(page); |
7b2d55d2 JG |
368 | |
369 | page->pgmap->page_free(page, page->pgmap->data); | |
370 | } else if (!count) | |
371 | __put_page(page); | |
372 | } | |
31c5bda3 | 373 | EXPORT_SYMBOL(__put_devmap_managed_page); |
e7638488 | 374 | #endif /* CONFIG_DEV_PAGEMAP_OPS */ |