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c942fddf | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
133ff0ea JG |
2 | /* |
3 | * Copyright 2013 Red Hat Inc. | |
4 | * | |
f813f219 | 5 | * Authors: Jérôme Glisse <jglisse@redhat.com> |
133ff0ea JG |
6 | */ |
7 | /* | |
8 | * Refer to include/linux/hmm.h for information about heterogeneous memory | |
9 | * management or HMM for short. | |
10 | */ | |
11 | #include <linux/mm.h> | |
12 | #include <linux/hmm.h> | |
858b54da | 13 | #include <linux/init.h> |
da4c3c73 JG |
14 | #include <linux/rmap.h> |
15 | #include <linux/swap.h> | |
133ff0ea JG |
16 | #include <linux/slab.h> |
17 | #include <linux/sched.h> | |
4ef589dc JG |
18 | #include <linux/mmzone.h> |
19 | #include <linux/pagemap.h> | |
da4c3c73 JG |
20 | #include <linux/swapops.h> |
21 | #include <linux/hugetlb.h> | |
4ef589dc | 22 | #include <linux/memremap.h> |
c8a53b2d | 23 | #include <linux/sched/mm.h> |
7b2d55d2 | 24 | #include <linux/jump_label.h> |
55c0ece8 | 25 | #include <linux/dma-mapping.h> |
c0b12405 | 26 | #include <linux/mmu_notifier.h> |
4ef589dc JG |
27 | #include <linux/memory_hotplug.h> |
28 | ||
29 | #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
133ff0ea | 30 | |
6b368cd4 | 31 | #if IS_ENABLED(CONFIG_HMM_MIRROR) |
c0b12405 JG |
32 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops; |
33 | ||
704f3f2c JG |
34 | /** |
35 | * hmm_get_or_create - register HMM against an mm (HMM internal) | |
133ff0ea JG |
36 | * |
37 | * @mm: mm struct to attach to | |
704f3f2c JG |
38 | * Returns: returns an HMM object, either by referencing the existing |
39 | * (per-process) object, or by creating a new one. | |
133ff0ea | 40 | * |
704f3f2c JG |
41 | * This is not intended to be used directly by device drivers. If mm already |
42 | * has an HMM struct then it get a reference on it and returns it. Otherwise | |
43 | * it allocates an HMM struct, initializes it, associate it with the mm and | |
44 | * returns it. | |
133ff0ea | 45 | */ |
704f3f2c | 46 | static struct hmm *hmm_get_or_create(struct mm_struct *mm) |
133ff0ea | 47 | { |
8a9320b7 JG |
48 | struct hmm *hmm; |
49 | ||
50 | lockdep_assert_held_exclusive(&mm->mmap_sem); | |
133ff0ea | 51 | |
8a9320b7 JG |
52 | /* Abuse the page_table_lock to also protect mm->hmm. */ |
53 | spin_lock(&mm->page_table_lock); | |
54 | hmm = mm->hmm; | |
55 | if (mm->hmm && kref_get_unless_zero(&mm->hmm->kref)) | |
56 | goto out_unlock; | |
57 | spin_unlock(&mm->page_table_lock); | |
c0b12405 JG |
58 | |
59 | hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); | |
60 | if (!hmm) | |
61 | return NULL; | |
a3e0d41c | 62 | init_waitqueue_head(&hmm->wq); |
c0b12405 JG |
63 | INIT_LIST_HEAD(&hmm->mirrors); |
64 | init_rwsem(&hmm->mirrors_sem); | |
c0b12405 | 65 | hmm->mmu_notifier.ops = NULL; |
da4c3c73 | 66 | INIT_LIST_HEAD(&hmm->ranges); |
a3e0d41c | 67 | mutex_init(&hmm->lock); |
704f3f2c | 68 | kref_init(&hmm->kref); |
a3e0d41c | 69 | hmm->notifiers = 0; |
c0b12405 JG |
70 | hmm->mm = mm; |
71 | ||
8a9320b7 JG |
72 | hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops; |
73 | if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) { | |
74 | kfree(hmm); | |
75 | return NULL; | |
76 | } | |
c0b12405 | 77 | |
8a9320b7 | 78 | mmgrab(hmm->mm); |
86a2d598 RC |
79 | |
80 | /* | |
8a9320b7 JG |
81 | * We hold the exclusive mmap_sem here so we know that mm->hmm is |
82 | * still NULL or 0 kref, and is safe to update. | |
86a2d598 | 83 | */ |
86a2d598 | 84 | spin_lock(&mm->page_table_lock); |
8a9320b7 JG |
85 | mm->hmm = hmm; |
86 | ||
87 | out_unlock: | |
86a2d598 | 88 | spin_unlock(&mm->page_table_lock); |
8a9320b7 | 89 | return hmm; |
133ff0ea JG |
90 | } |
91 | ||
6d7c3cde JG |
92 | static void hmm_free_rcu(struct rcu_head *rcu) |
93 | { | |
8a9320b7 JG |
94 | struct hmm *hmm = container_of(rcu, struct hmm, rcu); |
95 | ||
96 | mmdrop(hmm->mm); | |
97 | kfree(hmm); | |
6d7c3cde JG |
98 | } |
99 | ||
704f3f2c JG |
100 | static void hmm_free(struct kref *kref) |
101 | { | |
102 | struct hmm *hmm = container_of(kref, struct hmm, kref); | |
704f3f2c | 103 | |
8a9320b7 JG |
104 | spin_lock(&hmm->mm->page_table_lock); |
105 | if (hmm->mm->hmm == hmm) | |
106 | hmm->mm->hmm = NULL; | |
107 | spin_unlock(&hmm->mm->page_table_lock); | |
704f3f2c | 108 | |
8a9320b7 | 109 | mmu_notifier_unregister_no_release(&hmm->mmu_notifier, hmm->mm); |
6d7c3cde | 110 | mmu_notifier_call_srcu(&hmm->rcu, hmm_free_rcu); |
704f3f2c JG |
111 | } |
112 | ||
113 | static inline void hmm_put(struct hmm *hmm) | |
114 | { | |
115 | kref_put(&hmm->kref, hmm_free); | |
116 | } | |
117 | ||
a3e0d41c | 118 | static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) |
c0b12405 | 119 | { |
6d7c3cde | 120 | struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier); |
c0b12405 | 121 | struct hmm_mirror *mirror; |
da4c3c73 | 122 | |
6d7c3cde JG |
123 | /* Bail out if hmm is in the process of being freed */ |
124 | if (!kref_get_unless_zero(&hmm->kref)) | |
125 | return; | |
126 | ||
47f24598 JG |
127 | /* |
128 | * Since hmm_range_register() holds the mmget() lock hmm_release() is | |
129 | * prevented as long as a range exists. | |
130 | */ | |
131 | WARN_ON(!list_empty_careful(&hmm->ranges)); | |
e1401513 RC |
132 | |
133 | down_write(&hmm->mirrors_sem); | |
134 | mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror, | |
135 | list); | |
136 | while (mirror) { | |
137 | list_del_init(&mirror->list); | |
138 | if (mirror->ops->release) { | |
139 | /* | |
085ea250 RC |
140 | * Drop mirrors_sem so the release callback can wait |
141 | * on any pending work that might itself trigger a | |
142 | * mmu_notifier callback and thus would deadlock with | |
143 | * us. | |
e1401513 RC |
144 | */ |
145 | up_write(&hmm->mirrors_sem); | |
146 | mirror->ops->release(mirror); | |
147 | down_write(&hmm->mirrors_sem); | |
148 | } | |
149 | mirror = list_first_entry_or_null(&hmm->mirrors, | |
150 | struct hmm_mirror, list); | |
151 | } | |
152 | up_write(&hmm->mirrors_sem); | |
704f3f2c JG |
153 | |
154 | hmm_put(hmm); | |
e1401513 RC |
155 | } |
156 | ||
93065ac7 | 157 | static int hmm_invalidate_range_start(struct mmu_notifier *mn, |
a3e0d41c | 158 | const struct mmu_notifier_range *nrange) |
c0b12405 | 159 | { |
6d7c3cde | 160 | struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier); |
a3e0d41c | 161 | struct hmm_mirror *mirror; |
ec131b2d | 162 | struct hmm_update update; |
a3e0d41c JG |
163 | struct hmm_range *range; |
164 | int ret = 0; | |
c0b12405 | 165 | |
6d7c3cde JG |
166 | if (!kref_get_unless_zero(&hmm->kref)) |
167 | return 0; | |
c0b12405 | 168 | |
a3e0d41c JG |
169 | update.start = nrange->start; |
170 | update.end = nrange->end; | |
ec131b2d | 171 | update.event = HMM_UPDATE_INVALIDATE; |
dfcd6660 | 172 | update.blockable = mmu_notifier_range_blockable(nrange); |
a3e0d41c | 173 | |
dfcd6660 | 174 | if (mmu_notifier_range_blockable(nrange)) |
a3e0d41c JG |
175 | mutex_lock(&hmm->lock); |
176 | else if (!mutex_trylock(&hmm->lock)) { | |
177 | ret = -EAGAIN; | |
178 | goto out; | |
179 | } | |
180 | hmm->notifiers++; | |
181 | list_for_each_entry(range, &hmm->ranges, list) { | |
182 | if (update.end < range->start || update.start >= range->end) | |
183 | continue; | |
184 | ||
185 | range->valid = false; | |
186 | } | |
187 | mutex_unlock(&hmm->lock); | |
188 | ||
dfcd6660 | 189 | if (mmu_notifier_range_blockable(nrange)) |
a3e0d41c JG |
190 | down_read(&hmm->mirrors_sem); |
191 | else if (!down_read_trylock(&hmm->mirrors_sem)) { | |
192 | ret = -EAGAIN; | |
193 | goto out; | |
194 | } | |
195 | list_for_each_entry(mirror, &hmm->mirrors, list) { | |
196 | int ret; | |
197 | ||
198 | ret = mirror->ops->sync_cpu_device_pagetables(mirror, &update); | |
085ea250 RC |
199 | if (!update.blockable && ret == -EAGAIN) |
200 | break; | |
a3e0d41c JG |
201 | } |
202 | up_read(&hmm->mirrors_sem); | |
203 | ||
204 | out: | |
704f3f2c JG |
205 | hmm_put(hmm); |
206 | return ret; | |
c0b12405 JG |
207 | } |
208 | ||
209 | static void hmm_invalidate_range_end(struct mmu_notifier *mn, | |
a3e0d41c | 210 | const struct mmu_notifier_range *nrange) |
c0b12405 | 211 | { |
6d7c3cde | 212 | struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier); |
c0b12405 | 213 | |
6d7c3cde JG |
214 | if (!kref_get_unless_zero(&hmm->kref)) |
215 | return; | |
c0b12405 | 216 | |
a3e0d41c JG |
217 | mutex_lock(&hmm->lock); |
218 | hmm->notifiers--; | |
219 | if (!hmm->notifiers) { | |
220 | struct hmm_range *range; | |
221 | ||
222 | list_for_each_entry(range, &hmm->ranges, list) { | |
223 | if (range->valid) | |
224 | continue; | |
225 | range->valid = true; | |
226 | } | |
227 | wake_up_all(&hmm->wq); | |
228 | } | |
229 | mutex_unlock(&hmm->lock); | |
230 | ||
704f3f2c | 231 | hmm_put(hmm); |
c0b12405 JG |
232 | } |
233 | ||
234 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops = { | |
e1401513 | 235 | .release = hmm_release, |
c0b12405 JG |
236 | .invalidate_range_start = hmm_invalidate_range_start, |
237 | .invalidate_range_end = hmm_invalidate_range_end, | |
238 | }; | |
239 | ||
240 | /* | |
241 | * hmm_mirror_register() - register a mirror against an mm | |
242 | * | |
243 | * @mirror: new mirror struct to register | |
244 | * @mm: mm to register against | |
085ea250 | 245 | * Return: 0 on success, -ENOMEM if no memory, -EINVAL if invalid arguments |
c0b12405 JG |
246 | * |
247 | * To start mirroring a process address space, the device driver must register | |
248 | * an HMM mirror struct. | |
249 | * | |
250 | * THE mm->mmap_sem MUST BE HELD IN WRITE MODE ! | |
251 | */ | |
252 | int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) | |
253 | { | |
254 | /* Sanity check */ | |
255 | if (!mm || !mirror || !mirror->ops) | |
256 | return -EINVAL; | |
257 | ||
704f3f2c | 258 | mirror->hmm = hmm_get_or_create(mm); |
c0b12405 JG |
259 | if (!mirror->hmm) |
260 | return -ENOMEM; | |
261 | ||
262 | down_write(&mirror->hmm->mirrors_sem); | |
704f3f2c JG |
263 | list_add(&mirror->list, &mirror->hmm->mirrors); |
264 | up_write(&mirror->hmm->mirrors_sem); | |
c0b12405 JG |
265 | |
266 | return 0; | |
267 | } | |
268 | EXPORT_SYMBOL(hmm_mirror_register); | |
269 | ||
270 | /* | |
271 | * hmm_mirror_unregister() - unregister a mirror | |
272 | * | |
085ea250 | 273 | * @mirror: mirror struct to unregister |
c0b12405 JG |
274 | * |
275 | * Stop mirroring a process address space, and cleanup. | |
276 | */ | |
277 | void hmm_mirror_unregister(struct hmm_mirror *mirror) | |
278 | { | |
704f3f2c | 279 | struct hmm *hmm = READ_ONCE(mirror->hmm); |
c01cbba2 | 280 | |
704f3f2c | 281 | if (hmm == NULL) |
c01cbba2 | 282 | return; |
c0b12405 JG |
283 | |
284 | down_write(&hmm->mirrors_sem); | |
e1401513 | 285 | list_del_init(&mirror->list); |
704f3f2c | 286 | /* To protect us against double unregister ... */ |
c01cbba2 | 287 | mirror->hmm = NULL; |
c0b12405 | 288 | up_write(&hmm->mirrors_sem); |
c01cbba2 | 289 | |
704f3f2c | 290 | hmm_put(hmm); |
c0b12405 JG |
291 | } |
292 | EXPORT_SYMBOL(hmm_mirror_unregister); | |
da4c3c73 | 293 | |
74eee180 JG |
294 | struct hmm_vma_walk { |
295 | struct hmm_range *range; | |
992de9a8 | 296 | struct dev_pagemap *pgmap; |
74eee180 JG |
297 | unsigned long last; |
298 | bool fault; | |
299 | bool block; | |
74eee180 JG |
300 | }; |
301 | ||
2aee09d8 JG |
302 | static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, |
303 | bool write_fault, uint64_t *pfn) | |
74eee180 | 304 | { |
9b1ae605 | 305 | unsigned int flags = FAULT_FLAG_REMOTE; |
74eee180 | 306 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
f88a1e90 | 307 | struct hmm_range *range = hmm_vma_walk->range; |
74eee180 | 308 | struct vm_area_struct *vma = walk->vma; |
50a7ca3c | 309 | vm_fault_t ret; |
74eee180 JG |
310 | |
311 | flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; | |
2aee09d8 | 312 | flags |= write_fault ? FAULT_FLAG_WRITE : 0; |
50a7ca3c SJ |
313 | ret = handle_mm_fault(vma, addr, flags); |
314 | if (ret & VM_FAULT_RETRY) | |
73231612 | 315 | return -EAGAIN; |
50a7ca3c | 316 | if (ret & VM_FAULT_ERROR) { |
f88a1e90 | 317 | *pfn = range->values[HMM_PFN_ERROR]; |
74eee180 JG |
318 | return -EFAULT; |
319 | } | |
320 | ||
73231612 | 321 | return -EBUSY; |
74eee180 JG |
322 | } |
323 | ||
da4c3c73 JG |
324 | static int hmm_pfns_bad(unsigned long addr, |
325 | unsigned long end, | |
326 | struct mm_walk *walk) | |
327 | { | |
c719547f JG |
328 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
329 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 330 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
331 | unsigned long i; |
332 | ||
333 | i = (addr - range->start) >> PAGE_SHIFT; | |
334 | for (; addr < end; addr += PAGE_SIZE, i++) | |
f88a1e90 | 335 | pfns[i] = range->values[HMM_PFN_ERROR]; |
da4c3c73 JG |
336 | |
337 | return 0; | |
338 | } | |
339 | ||
5504ed29 JG |
340 | /* |
341 | * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) | |
342 | * @start: range virtual start address (inclusive) | |
343 | * @end: range virtual end address (exclusive) | |
2aee09d8 JG |
344 | * @fault: should we fault or not ? |
345 | * @write_fault: write fault ? | |
5504ed29 | 346 | * @walk: mm_walk structure |
085ea250 | 347 | * Return: 0 on success, -EBUSY after page fault, or page fault error |
5504ed29 JG |
348 | * |
349 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
350 | * or whenever there is no page directory covering the virtual address range. | |
351 | */ | |
2aee09d8 JG |
352 | static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, |
353 | bool fault, bool write_fault, | |
354 | struct mm_walk *walk) | |
da4c3c73 | 355 | { |
74eee180 JG |
356 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
357 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 358 | uint64_t *pfns = range->pfns; |
63d5066f | 359 | unsigned long i, page_size; |
da4c3c73 | 360 | |
74eee180 | 361 | hmm_vma_walk->last = addr; |
63d5066f JG |
362 | page_size = hmm_range_page_size(range); |
363 | i = (addr - range->start) >> range->page_shift; | |
364 | ||
365 | for (; addr < end; addr += page_size, i++) { | |
f88a1e90 | 366 | pfns[i] = range->values[HMM_PFN_NONE]; |
2aee09d8 | 367 | if (fault || write_fault) { |
74eee180 | 368 | int ret; |
da4c3c73 | 369 | |
2aee09d8 JG |
370 | ret = hmm_vma_do_fault(walk, addr, write_fault, |
371 | &pfns[i]); | |
73231612 | 372 | if (ret != -EBUSY) |
74eee180 JG |
373 | return ret; |
374 | } | |
375 | } | |
376 | ||
73231612 | 377 | return (fault || write_fault) ? -EBUSY : 0; |
2aee09d8 JG |
378 | } |
379 | ||
380 | static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
381 | uint64_t pfns, uint64_t cpu_flags, | |
382 | bool *fault, bool *write_fault) | |
383 | { | |
f88a1e90 JG |
384 | struct hmm_range *range = hmm_vma_walk->range; |
385 | ||
2aee09d8 JG |
386 | if (!hmm_vma_walk->fault) |
387 | return; | |
388 | ||
023a019a JG |
389 | /* |
390 | * So we not only consider the individual per page request we also | |
391 | * consider the default flags requested for the range. The API can | |
392 | * be use in 2 fashions. The first one where the HMM user coalesce | |
393 | * multiple page fault into one request and set flags per pfns for | |
394 | * of those faults. The second one where the HMM user want to pre- | |
395 | * fault a range with specific flags. For the latter one it is a | |
396 | * waste to have the user pre-fill the pfn arrays with a default | |
397 | * flags value. | |
398 | */ | |
399 | pfns = (pfns & range->pfn_flags_mask) | range->default_flags; | |
400 | ||
2aee09d8 | 401 | /* We aren't ask to do anything ... */ |
f88a1e90 | 402 | if (!(pfns & range->flags[HMM_PFN_VALID])) |
2aee09d8 | 403 | return; |
f88a1e90 JG |
404 | /* If this is device memory than only fault if explicitly requested */ |
405 | if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { | |
406 | /* Do we fault on device memory ? */ | |
407 | if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { | |
408 | *write_fault = pfns & range->flags[HMM_PFN_WRITE]; | |
409 | *fault = true; | |
410 | } | |
2aee09d8 JG |
411 | return; |
412 | } | |
f88a1e90 JG |
413 | |
414 | /* If CPU page table is not valid then we need to fault */ | |
415 | *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); | |
416 | /* Need to write fault ? */ | |
417 | if ((pfns & range->flags[HMM_PFN_WRITE]) && | |
418 | !(cpu_flags & range->flags[HMM_PFN_WRITE])) { | |
419 | *write_fault = true; | |
2aee09d8 JG |
420 | *fault = true; |
421 | } | |
422 | } | |
423 | ||
424 | static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, | |
425 | const uint64_t *pfns, unsigned long npages, | |
426 | uint64_t cpu_flags, bool *fault, | |
427 | bool *write_fault) | |
428 | { | |
429 | unsigned long i; | |
430 | ||
431 | if (!hmm_vma_walk->fault) { | |
432 | *fault = *write_fault = false; | |
433 | return; | |
434 | } | |
435 | ||
a3e0d41c | 436 | *fault = *write_fault = false; |
2aee09d8 JG |
437 | for (i = 0; i < npages; ++i) { |
438 | hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, | |
439 | fault, write_fault); | |
a3e0d41c | 440 | if ((*write_fault)) |
2aee09d8 JG |
441 | return; |
442 | } | |
443 | } | |
444 | ||
445 | static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, | |
446 | struct mm_walk *walk) | |
447 | { | |
448 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
449 | struct hmm_range *range = hmm_vma_walk->range; | |
450 | bool fault, write_fault; | |
451 | unsigned long i, npages; | |
452 | uint64_t *pfns; | |
453 | ||
454 | i = (addr - range->start) >> PAGE_SHIFT; | |
455 | npages = (end - addr) >> PAGE_SHIFT; | |
456 | pfns = &range->pfns[i]; | |
457 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
458 | 0, &fault, &write_fault); | |
459 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); | |
460 | } | |
461 | ||
f88a1e90 | 462 | static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
2aee09d8 JG |
463 | { |
464 | if (pmd_protnone(pmd)) | |
465 | return 0; | |
f88a1e90 JG |
466 | return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
467 | range->flags[HMM_PFN_WRITE] : | |
468 | range->flags[HMM_PFN_VALID]; | |
da4c3c73 JG |
469 | } |
470 | ||
992de9a8 JG |
471 | static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) |
472 | { | |
473 | if (!pud_present(pud)) | |
474 | return 0; | |
475 | return pud_write(pud) ? range->flags[HMM_PFN_VALID] | | |
476 | range->flags[HMM_PFN_WRITE] : | |
477 | range->flags[HMM_PFN_VALID]; | |
478 | } | |
479 | ||
53f5c3f4 JG |
480 | static int hmm_vma_handle_pmd(struct mm_walk *walk, |
481 | unsigned long addr, | |
482 | unsigned long end, | |
483 | uint64_t *pfns, | |
484 | pmd_t pmd) | |
485 | { | |
992de9a8 | 486 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
53f5c3f4 | 487 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
f88a1e90 | 488 | struct hmm_range *range = hmm_vma_walk->range; |
2aee09d8 | 489 | unsigned long pfn, npages, i; |
2aee09d8 | 490 | bool fault, write_fault; |
f88a1e90 | 491 | uint64_t cpu_flags; |
53f5c3f4 | 492 | |
2aee09d8 | 493 | npages = (end - addr) >> PAGE_SHIFT; |
f88a1e90 | 494 | cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
2aee09d8 JG |
495 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, |
496 | &fault, &write_fault); | |
53f5c3f4 | 497 | |
2aee09d8 JG |
498 | if (pmd_protnone(pmd) || fault || write_fault) |
499 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); | |
53f5c3f4 JG |
500 | |
501 | pfn = pmd_pfn(pmd) + pte_index(addr); | |
992de9a8 JG |
502 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { |
503 | if (pmd_devmap(pmd)) { | |
504 | hmm_vma_walk->pgmap = get_dev_pagemap(pfn, | |
505 | hmm_vma_walk->pgmap); | |
506 | if (unlikely(!hmm_vma_walk->pgmap)) | |
507 | return -EBUSY; | |
508 | } | |
391aab11 | 509 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; |
992de9a8 JG |
510 | } |
511 | if (hmm_vma_walk->pgmap) { | |
512 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
513 | hmm_vma_walk->pgmap = NULL; | |
514 | } | |
53f5c3f4 JG |
515 | hmm_vma_walk->last = end; |
516 | return 0; | |
992de9a8 JG |
517 | #else |
518 | /* If THP is not enabled then we should never reach that code ! */ | |
519 | return -EINVAL; | |
520 | #endif | |
53f5c3f4 JG |
521 | } |
522 | ||
f88a1e90 | 523 | static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
2aee09d8 | 524 | { |
789c2af8 | 525 | if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte)) |
2aee09d8 | 526 | return 0; |
f88a1e90 JG |
527 | return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
528 | range->flags[HMM_PFN_WRITE] : | |
529 | range->flags[HMM_PFN_VALID]; | |
2aee09d8 JG |
530 | } |
531 | ||
53f5c3f4 JG |
532 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
533 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
534 | uint64_t *pfn) | |
535 | { | |
536 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
f88a1e90 | 537 | struct hmm_range *range = hmm_vma_walk->range; |
53f5c3f4 | 538 | struct vm_area_struct *vma = walk->vma; |
2aee09d8 JG |
539 | bool fault, write_fault; |
540 | uint64_t cpu_flags; | |
53f5c3f4 | 541 | pte_t pte = *ptep; |
f88a1e90 | 542 | uint64_t orig_pfn = *pfn; |
53f5c3f4 | 543 | |
f88a1e90 | 544 | *pfn = range->values[HMM_PFN_NONE]; |
73231612 | 545 | fault = write_fault = false; |
53f5c3f4 JG |
546 | |
547 | if (pte_none(pte)) { | |
73231612 JG |
548 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, |
549 | &fault, &write_fault); | |
2aee09d8 | 550 | if (fault || write_fault) |
53f5c3f4 JG |
551 | goto fault; |
552 | return 0; | |
553 | } | |
554 | ||
555 | if (!pte_present(pte)) { | |
556 | swp_entry_t entry = pte_to_swp_entry(pte); | |
557 | ||
558 | if (!non_swap_entry(entry)) { | |
2aee09d8 | 559 | if (fault || write_fault) |
53f5c3f4 JG |
560 | goto fault; |
561 | return 0; | |
562 | } | |
563 | ||
564 | /* | |
565 | * This is a special swap entry, ignore migration, use | |
566 | * device and report anything else as error. | |
567 | */ | |
568 | if (is_device_private_entry(entry)) { | |
f88a1e90 JG |
569 | cpu_flags = range->flags[HMM_PFN_VALID] | |
570 | range->flags[HMM_PFN_DEVICE_PRIVATE]; | |
2aee09d8 | 571 | cpu_flags |= is_write_device_private_entry(entry) ? |
f88a1e90 JG |
572 | range->flags[HMM_PFN_WRITE] : 0; |
573 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
574 | &fault, &write_fault); | |
575 | if (fault || write_fault) | |
576 | goto fault; | |
391aab11 JG |
577 | *pfn = hmm_device_entry_from_pfn(range, |
578 | swp_offset(entry)); | |
f88a1e90 | 579 | *pfn |= cpu_flags; |
53f5c3f4 JG |
580 | return 0; |
581 | } | |
582 | ||
583 | if (is_migration_entry(entry)) { | |
2aee09d8 | 584 | if (fault || write_fault) { |
53f5c3f4 JG |
585 | pte_unmap(ptep); |
586 | hmm_vma_walk->last = addr; | |
587 | migration_entry_wait(vma->vm_mm, | |
2aee09d8 | 588 | pmdp, addr); |
73231612 | 589 | return -EBUSY; |
53f5c3f4 JG |
590 | } |
591 | return 0; | |
592 | } | |
593 | ||
594 | /* Report error for everything else */ | |
f88a1e90 | 595 | *pfn = range->values[HMM_PFN_ERROR]; |
53f5c3f4 | 596 | return -EFAULT; |
73231612 JG |
597 | } else { |
598 | cpu_flags = pte_to_hmm_pfn_flags(range, pte); | |
599 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
600 | &fault, &write_fault); | |
53f5c3f4 JG |
601 | } |
602 | ||
2aee09d8 | 603 | if (fault || write_fault) |
53f5c3f4 JG |
604 | goto fault; |
605 | ||
992de9a8 JG |
606 | if (pte_devmap(pte)) { |
607 | hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte), | |
608 | hmm_vma_walk->pgmap); | |
609 | if (unlikely(!hmm_vma_walk->pgmap)) | |
610 | return -EBUSY; | |
611 | } else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) { | |
612 | *pfn = range->values[HMM_PFN_SPECIAL]; | |
613 | return -EFAULT; | |
614 | } | |
615 | ||
391aab11 | 616 | *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
53f5c3f4 JG |
617 | return 0; |
618 | ||
619 | fault: | |
992de9a8 JG |
620 | if (hmm_vma_walk->pgmap) { |
621 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
622 | hmm_vma_walk->pgmap = NULL; | |
623 | } | |
53f5c3f4 JG |
624 | pte_unmap(ptep); |
625 | /* Fault any virtual address we were asked to fault */ | |
2aee09d8 | 626 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
53f5c3f4 JG |
627 | } |
628 | ||
da4c3c73 JG |
629 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
630 | unsigned long start, | |
631 | unsigned long end, | |
632 | struct mm_walk *walk) | |
633 | { | |
74eee180 JG |
634 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
635 | struct hmm_range *range = hmm_vma_walk->range; | |
d08faca0 | 636 | struct vm_area_struct *vma = walk->vma; |
ff05c0c6 | 637 | uint64_t *pfns = range->pfns; |
da4c3c73 | 638 | unsigned long addr = start, i; |
da4c3c73 | 639 | pte_t *ptep; |
d08faca0 | 640 | pmd_t pmd; |
da4c3c73 | 641 | |
da4c3c73 JG |
642 | |
643 | again: | |
d08faca0 JG |
644 | pmd = READ_ONCE(*pmdp); |
645 | if (pmd_none(pmd)) | |
da4c3c73 JG |
646 | return hmm_vma_walk_hole(start, end, walk); |
647 | ||
d08faca0 | 648 | if (pmd_huge(pmd) && (range->vma->vm_flags & VM_HUGETLB)) |
da4c3c73 JG |
649 | return hmm_pfns_bad(start, end, walk); |
650 | ||
d08faca0 JG |
651 | if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
652 | bool fault, write_fault; | |
653 | unsigned long npages; | |
654 | uint64_t *pfns; | |
655 | ||
656 | i = (addr - range->start) >> PAGE_SHIFT; | |
657 | npages = (end - addr) >> PAGE_SHIFT; | |
658 | pfns = &range->pfns[i]; | |
659 | ||
660 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
661 | 0, &fault, &write_fault); | |
662 | if (fault || write_fault) { | |
663 | hmm_vma_walk->last = addr; | |
664 | pmd_migration_entry_wait(vma->vm_mm, pmdp); | |
73231612 | 665 | return -EBUSY; |
d08faca0 JG |
666 | } |
667 | return 0; | |
668 | } else if (!pmd_present(pmd)) | |
669 | return hmm_pfns_bad(start, end, walk); | |
da4c3c73 | 670 | |
d08faca0 | 671 | if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
da4c3c73 JG |
672 | /* |
673 | * No need to take pmd_lock here, even if some other threads | |
674 | * is splitting the huge pmd we will get that event through | |
675 | * mmu_notifier callback. | |
676 | * | |
677 | * So just read pmd value and check again its a transparent | |
678 | * huge or device mapping one and compute corresponding pfn | |
679 | * values. | |
680 | */ | |
681 | pmd = pmd_read_atomic(pmdp); | |
682 | barrier(); | |
683 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
684 | goto again; | |
74eee180 | 685 | |
d08faca0 | 686 | i = (addr - range->start) >> PAGE_SHIFT; |
53f5c3f4 | 687 | return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd); |
da4c3c73 JG |
688 | } |
689 | ||
d08faca0 JG |
690 | /* |
691 | * We have handled all the valid case above ie either none, migration, | |
692 | * huge or transparent huge. At this point either it is a valid pmd | |
693 | * entry pointing to pte directory or it is a bad pmd that will not | |
694 | * recover. | |
695 | */ | |
696 | if (pmd_bad(pmd)) | |
da4c3c73 JG |
697 | return hmm_pfns_bad(start, end, walk); |
698 | ||
699 | ptep = pte_offset_map(pmdp, addr); | |
d08faca0 | 700 | i = (addr - range->start) >> PAGE_SHIFT; |
da4c3c73 | 701 | for (; addr < end; addr += PAGE_SIZE, ptep++, i++) { |
53f5c3f4 | 702 | int r; |
74eee180 | 703 | |
53f5c3f4 JG |
704 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]); |
705 | if (r) { | |
706 | /* hmm_vma_handle_pte() did unmap pte directory */ | |
707 | hmm_vma_walk->last = addr; | |
708 | return r; | |
74eee180 | 709 | } |
da4c3c73 | 710 | } |
992de9a8 JG |
711 | if (hmm_vma_walk->pgmap) { |
712 | /* | |
713 | * We do put_dev_pagemap() here and not in hmm_vma_handle_pte() | |
714 | * so that we can leverage get_dev_pagemap() optimization which | |
715 | * will not re-take a reference on a pgmap if we already have | |
716 | * one. | |
717 | */ | |
718 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
719 | hmm_vma_walk->pgmap = NULL; | |
720 | } | |
da4c3c73 JG |
721 | pte_unmap(ptep - 1); |
722 | ||
53f5c3f4 | 723 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
724 | return 0; |
725 | } | |
726 | ||
992de9a8 JG |
727 | static int hmm_vma_walk_pud(pud_t *pudp, |
728 | unsigned long start, | |
729 | unsigned long end, | |
730 | struct mm_walk *walk) | |
731 | { | |
732 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
733 | struct hmm_range *range = hmm_vma_walk->range; | |
734 | unsigned long addr = start, next; | |
735 | pmd_t *pmdp; | |
736 | pud_t pud; | |
737 | int ret; | |
738 | ||
739 | again: | |
740 | pud = READ_ONCE(*pudp); | |
741 | if (pud_none(pud)) | |
742 | return hmm_vma_walk_hole(start, end, walk); | |
743 | ||
744 | if (pud_huge(pud) && pud_devmap(pud)) { | |
745 | unsigned long i, npages, pfn; | |
746 | uint64_t *pfns, cpu_flags; | |
747 | bool fault, write_fault; | |
748 | ||
749 | if (!pud_present(pud)) | |
750 | return hmm_vma_walk_hole(start, end, walk); | |
751 | ||
752 | i = (addr - range->start) >> PAGE_SHIFT; | |
753 | npages = (end - addr) >> PAGE_SHIFT; | |
754 | pfns = &range->pfns[i]; | |
755 | ||
756 | cpu_flags = pud_to_hmm_pfn_flags(range, pud); | |
757 | hmm_range_need_fault(hmm_vma_walk, pfns, npages, | |
758 | cpu_flags, &fault, &write_fault); | |
759 | if (fault || write_fault) | |
760 | return hmm_vma_walk_hole_(addr, end, fault, | |
761 | write_fault, walk); | |
762 | ||
992de9a8 JG |
763 | pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); |
764 | for (i = 0; i < npages; ++i, ++pfn) { | |
765 | hmm_vma_walk->pgmap = get_dev_pagemap(pfn, | |
766 | hmm_vma_walk->pgmap); | |
767 | if (unlikely(!hmm_vma_walk->pgmap)) | |
768 | return -EBUSY; | |
391aab11 JG |
769 | pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
770 | cpu_flags; | |
992de9a8 JG |
771 | } |
772 | if (hmm_vma_walk->pgmap) { | |
773 | put_dev_pagemap(hmm_vma_walk->pgmap); | |
774 | hmm_vma_walk->pgmap = NULL; | |
775 | } | |
776 | hmm_vma_walk->last = end; | |
777 | return 0; | |
992de9a8 JG |
778 | } |
779 | ||
780 | split_huge_pud(walk->vma, pudp, addr); | |
781 | if (pud_none(*pudp)) | |
782 | goto again; | |
783 | ||
784 | pmdp = pmd_offset(pudp, addr); | |
785 | do { | |
786 | next = pmd_addr_end(addr, end); | |
787 | ret = hmm_vma_walk_pmd(pmdp, addr, next, walk); | |
788 | if (ret) | |
789 | return ret; | |
790 | } while (pmdp++, addr = next, addr != end); | |
791 | ||
792 | return 0; | |
793 | } | |
794 | ||
63d5066f JG |
795 | static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, |
796 | unsigned long start, unsigned long end, | |
797 | struct mm_walk *walk) | |
798 | { | |
799 | #ifdef CONFIG_HUGETLB_PAGE | |
800 | unsigned long addr = start, i, pfn, mask, size, pfn_inc; | |
801 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
802 | struct hmm_range *range = hmm_vma_walk->range; | |
803 | struct vm_area_struct *vma = walk->vma; | |
804 | struct hstate *h = hstate_vma(vma); | |
805 | uint64_t orig_pfn, cpu_flags; | |
806 | bool fault, write_fault; | |
807 | spinlock_t *ptl; | |
808 | pte_t entry; | |
809 | int ret = 0; | |
810 | ||
811 | size = 1UL << huge_page_shift(h); | |
812 | mask = size - 1; | |
813 | if (range->page_shift != PAGE_SHIFT) { | |
814 | /* Make sure we are looking at full page. */ | |
815 | if (start & mask) | |
816 | return -EINVAL; | |
817 | if (end < (start + size)) | |
818 | return -EINVAL; | |
819 | pfn_inc = size >> PAGE_SHIFT; | |
820 | } else { | |
821 | pfn_inc = 1; | |
822 | size = PAGE_SIZE; | |
823 | } | |
824 | ||
825 | ||
826 | ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte); | |
827 | entry = huge_ptep_get(pte); | |
828 | ||
829 | i = (start - range->start) >> range->page_shift; | |
830 | orig_pfn = range->pfns[i]; | |
831 | range->pfns[i] = range->values[HMM_PFN_NONE]; | |
832 | cpu_flags = pte_to_hmm_pfn_flags(range, entry); | |
833 | fault = write_fault = false; | |
834 | hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, | |
835 | &fault, &write_fault); | |
836 | if (fault || write_fault) { | |
837 | ret = -ENOENT; | |
838 | goto unlock; | |
839 | } | |
840 | ||
841 | pfn = pte_pfn(entry) + ((start & mask) >> range->page_shift); | |
842 | for (; addr < end; addr += size, i++, pfn += pfn_inc) | |
391aab11 JG |
843 | range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
844 | cpu_flags; | |
63d5066f JG |
845 | hmm_vma_walk->last = end; |
846 | ||
847 | unlock: | |
848 | spin_unlock(ptl); | |
849 | ||
850 | if (ret == -ENOENT) | |
851 | return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); | |
852 | ||
853 | return ret; | |
854 | #else /* CONFIG_HUGETLB_PAGE */ | |
855 | return -EINVAL; | |
856 | #endif | |
857 | } | |
858 | ||
f88a1e90 JG |
859 | static void hmm_pfns_clear(struct hmm_range *range, |
860 | uint64_t *pfns, | |
33cd47dc JG |
861 | unsigned long addr, |
862 | unsigned long end) | |
863 | { | |
864 | for (; addr < end; addr += PAGE_SIZE, pfns++) | |
f88a1e90 | 865 | *pfns = range->values[HMM_PFN_NONE]; |
33cd47dc JG |
866 | } |
867 | ||
da4c3c73 | 868 | /* |
a3e0d41c | 869 | * hmm_range_register() - start tracking change to CPU page table over a range |
25f23a0c | 870 | * @range: range |
a3e0d41c JG |
871 | * @mm: the mm struct for the range of virtual address |
872 | * @start: start virtual address (inclusive) | |
873 | * @end: end virtual address (exclusive) | |
63d5066f | 874 | * @page_shift: expect page shift for the range |
a3e0d41c | 875 | * Returns 0 on success, -EFAULT if the address space is no longer valid |
25f23a0c | 876 | * |
a3e0d41c | 877 | * Track updates to the CPU page table see include/linux/hmm.h |
da4c3c73 | 878 | */ |
a3e0d41c | 879 | int hmm_range_register(struct hmm_range *range, |
e36acfe6 | 880 | struct hmm_mirror *mirror, |
a3e0d41c | 881 | unsigned long start, |
63d5066f JG |
882 | unsigned long end, |
883 | unsigned page_shift) | |
da4c3c73 | 884 | { |
63d5066f | 885 | unsigned long mask = ((1UL << page_shift) - 1UL); |
e36acfe6 | 886 | struct hmm *hmm = mirror->hmm; |
63d5066f | 887 | |
a3e0d41c | 888 | range->valid = false; |
704f3f2c JG |
889 | range->hmm = NULL; |
890 | ||
63d5066f JG |
891 | if ((start & mask) || (end & mask)) |
892 | return -EINVAL; | |
893 | if (start >= end) | |
da4c3c73 JG |
894 | return -EINVAL; |
895 | ||
63d5066f | 896 | range->page_shift = page_shift; |
a3e0d41c JG |
897 | range->start = start; |
898 | range->end = end; | |
899 | ||
47f24598 JG |
900 | /* Prevent hmm_release() from running while the range is valid */ |
901 | if (!mmget_not_zero(hmm->mm)) | |
a3e0d41c | 902 | return -EFAULT; |
da4c3c73 | 903 | |
085ea250 RC |
904 | /* Initialize range to track CPU page table updates. */ |
905 | mutex_lock(&hmm->lock); | |
855ce7d2 | 906 | |
085ea250 | 907 | range->hmm = hmm; |
e36acfe6 | 908 | kref_get(&hmm->kref); |
157816f3 | 909 | list_add(&range->list, &hmm->ranges); |
86586a41 | 910 | |
704f3f2c | 911 | /* |
a3e0d41c JG |
912 | * If there are any concurrent notifiers we have to wait for them for |
913 | * the range to be valid (see hmm_range_wait_until_valid()). | |
704f3f2c | 914 | */ |
085ea250 | 915 | if (!hmm->notifiers) |
a3e0d41c | 916 | range->valid = true; |
085ea250 | 917 | mutex_unlock(&hmm->lock); |
a3e0d41c JG |
918 | |
919 | return 0; | |
da4c3c73 | 920 | } |
a3e0d41c | 921 | EXPORT_SYMBOL(hmm_range_register); |
da4c3c73 JG |
922 | |
923 | /* | |
a3e0d41c JG |
924 | * hmm_range_unregister() - stop tracking change to CPU page table over a range |
925 | * @range: range | |
da4c3c73 JG |
926 | * |
927 | * Range struct is used to track updates to the CPU page table after a call to | |
a3e0d41c | 928 | * hmm_range_register(). See include/linux/hmm.h for how to use it. |
da4c3c73 | 929 | */ |
a3e0d41c | 930 | void hmm_range_unregister(struct hmm_range *range) |
da4c3c73 | 931 | { |
085ea250 RC |
932 | struct hmm *hmm = range->hmm; |
933 | ||
704f3f2c | 934 | /* Sanity check this really should not happen. */ |
085ea250 | 935 | if (hmm == NULL || range->end <= range->start) |
a3e0d41c | 936 | return; |
da4c3c73 | 937 | |
085ea250 | 938 | mutex_lock(&hmm->lock); |
47f24598 | 939 | list_del_init(&range->list); |
085ea250 | 940 | mutex_unlock(&hmm->lock); |
da4c3c73 | 941 | |
a3e0d41c JG |
942 | /* Drop reference taken by hmm_range_register() */ |
943 | range->valid = false; | |
47f24598 | 944 | mmput(hmm->mm); |
085ea250 | 945 | hmm_put(hmm); |
704f3f2c | 946 | range->hmm = NULL; |
da4c3c73 | 947 | } |
a3e0d41c JG |
948 | EXPORT_SYMBOL(hmm_range_unregister); |
949 | ||
950 | /* | |
951 | * hmm_range_snapshot() - snapshot CPU page table for a range | |
952 | * @range: range | |
085ea250 | 953 | * Return: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid |
a3e0d41c JG |
954 | * permission (for instance asking for write and range is read only), |
955 | * -EAGAIN if you need to retry, -EFAULT invalid (ie either no valid | |
956 | * vma or it is illegal to access that range), number of valid pages | |
957 | * in range->pfns[] (from range start address). | |
958 | * | |
959 | * This snapshots the CPU page table for a range of virtual addresses. Snapshot | |
960 | * validity is tracked by range struct. See in include/linux/hmm.h for example | |
961 | * on how to use. | |
962 | */ | |
963 | long hmm_range_snapshot(struct hmm_range *range) | |
964 | { | |
63d5066f | 965 | const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; |
a3e0d41c JG |
966 | unsigned long start = range->start, end; |
967 | struct hmm_vma_walk hmm_vma_walk; | |
968 | struct hmm *hmm = range->hmm; | |
969 | struct vm_area_struct *vma; | |
970 | struct mm_walk mm_walk; | |
971 | ||
47f24598 | 972 | lockdep_assert_held(&hmm->mm->mmap_sem); |
a3e0d41c JG |
973 | do { |
974 | /* If range is no longer valid force retry. */ | |
975 | if (!range->valid) | |
976 | return -EAGAIN; | |
977 | ||
978 | vma = find_vma(hmm->mm, start); | |
63d5066f | 979 | if (vma == NULL || (vma->vm_flags & device_vma)) |
a3e0d41c JG |
980 | return -EFAULT; |
981 | ||
63d5066f | 982 | if (is_vm_hugetlb_page(vma)) { |
1c2308f0 JG |
983 | if (huge_page_shift(hstate_vma(vma)) != |
984 | range->page_shift && | |
63d5066f JG |
985 | range->page_shift != PAGE_SHIFT) |
986 | return -EINVAL; | |
987 | } else { | |
988 | if (range->page_shift != PAGE_SHIFT) | |
989 | return -EINVAL; | |
990 | } | |
991 | ||
a3e0d41c JG |
992 | if (!(vma->vm_flags & VM_READ)) { |
993 | /* | |
994 | * If vma do not allow read access, then assume that it | |
995 | * does not allow write access, either. HMM does not | |
996 | * support architecture that allow write without read. | |
997 | */ | |
998 | hmm_pfns_clear(range, range->pfns, | |
999 | range->start, range->end); | |
1000 | return -EPERM; | |
1001 | } | |
1002 | ||
1003 | range->vma = vma; | |
992de9a8 | 1004 | hmm_vma_walk.pgmap = NULL; |
a3e0d41c JG |
1005 | hmm_vma_walk.last = start; |
1006 | hmm_vma_walk.fault = false; | |
1007 | hmm_vma_walk.range = range; | |
1008 | mm_walk.private = &hmm_vma_walk; | |
1009 | end = min(range->end, vma->vm_end); | |
1010 | ||
1011 | mm_walk.vma = vma; | |
1012 | mm_walk.mm = vma->vm_mm; | |
1013 | mm_walk.pte_entry = NULL; | |
1014 | mm_walk.test_walk = NULL; | |
1015 | mm_walk.hugetlb_entry = NULL; | |
992de9a8 | 1016 | mm_walk.pud_entry = hmm_vma_walk_pud; |
a3e0d41c JG |
1017 | mm_walk.pmd_entry = hmm_vma_walk_pmd; |
1018 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
63d5066f | 1019 | mm_walk.hugetlb_entry = hmm_vma_walk_hugetlb_entry; |
a3e0d41c JG |
1020 | |
1021 | walk_page_range(start, end, &mm_walk); | |
1022 | start = end; | |
1023 | } while (start < range->end); | |
1024 | ||
1025 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; | |
1026 | } | |
1027 | EXPORT_SYMBOL(hmm_range_snapshot); | |
74eee180 JG |
1028 | |
1029 | /* | |
73231612 | 1030 | * hmm_range_fault() - try to fault some address in a virtual address range |
08232a45 | 1031 | * @range: range being faulted |
74eee180 | 1032 | * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) |
085ea250 | 1033 | * Return: number of valid pages in range->pfns[] (from range start |
73231612 JG |
1034 | * address). This may be zero. If the return value is negative, |
1035 | * then one of the following values may be returned: | |
1036 | * | |
1037 | * -EINVAL invalid arguments or mm or virtual address are in an | |
63d5066f | 1038 | * invalid vma (for instance device file vma). |
73231612 JG |
1039 | * -ENOMEM: Out of memory. |
1040 | * -EPERM: Invalid permission (for instance asking for write and | |
1041 | * range is read only). | |
1042 | * -EAGAIN: If you need to retry and mmap_sem was drop. This can only | |
1043 | * happens if block argument is false. | |
1044 | * -EBUSY: If the the range is being invalidated and you should wait | |
1045 | * for invalidation to finish. | |
1046 | * -EFAULT: Invalid (ie either no valid vma or it is illegal to access | |
1047 | * that range), number of valid pages in range->pfns[] (from | |
1048 | * range start address). | |
74eee180 JG |
1049 | * |
1050 | * This is similar to a regular CPU page fault except that it will not trigger | |
73231612 JG |
1051 | * any memory migration if the memory being faulted is not accessible by CPUs |
1052 | * and caller does not ask for migration. | |
74eee180 | 1053 | * |
ff05c0c6 JG |
1054 | * On error, for one virtual address in the range, the function will mark the |
1055 | * corresponding HMM pfn entry with an error flag. | |
74eee180 | 1056 | */ |
73231612 | 1057 | long hmm_range_fault(struct hmm_range *range, bool block) |
74eee180 | 1058 | { |
63d5066f | 1059 | const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; |
a3e0d41c | 1060 | unsigned long start = range->start, end; |
74eee180 | 1061 | struct hmm_vma_walk hmm_vma_walk; |
a3e0d41c JG |
1062 | struct hmm *hmm = range->hmm; |
1063 | struct vm_area_struct *vma; | |
74eee180 | 1064 | struct mm_walk mm_walk; |
74eee180 JG |
1065 | int ret; |
1066 | ||
47f24598 | 1067 | lockdep_assert_held(&hmm->mm->mmap_sem); |
704f3f2c | 1068 | |
a3e0d41c JG |
1069 | do { |
1070 | /* If range is no longer valid force retry. */ | |
1071 | if (!range->valid) { | |
1072 | up_read(&hmm->mm->mmap_sem); | |
1073 | return -EAGAIN; | |
1074 | } | |
74eee180 | 1075 | |
a3e0d41c | 1076 | vma = find_vma(hmm->mm, start); |
63d5066f | 1077 | if (vma == NULL || (vma->vm_flags & device_vma)) |
a3e0d41c | 1078 | return -EFAULT; |
704f3f2c | 1079 | |
63d5066f JG |
1080 | if (is_vm_hugetlb_page(vma)) { |
1081 | if (huge_page_shift(hstate_vma(vma)) != | |
1082 | range->page_shift && | |
1083 | range->page_shift != PAGE_SHIFT) | |
1084 | return -EINVAL; | |
1085 | } else { | |
1086 | if (range->page_shift != PAGE_SHIFT) | |
1087 | return -EINVAL; | |
1088 | } | |
1089 | ||
a3e0d41c JG |
1090 | if (!(vma->vm_flags & VM_READ)) { |
1091 | /* | |
1092 | * If vma do not allow read access, then assume that it | |
1093 | * does not allow write access, either. HMM does not | |
1094 | * support architecture that allow write without read. | |
1095 | */ | |
1096 | hmm_pfns_clear(range, range->pfns, | |
1097 | range->start, range->end); | |
1098 | return -EPERM; | |
1099 | } | |
74eee180 | 1100 | |
a3e0d41c | 1101 | range->vma = vma; |
992de9a8 | 1102 | hmm_vma_walk.pgmap = NULL; |
a3e0d41c JG |
1103 | hmm_vma_walk.last = start; |
1104 | hmm_vma_walk.fault = true; | |
1105 | hmm_vma_walk.block = block; | |
1106 | hmm_vma_walk.range = range; | |
1107 | mm_walk.private = &hmm_vma_walk; | |
1108 | end = min(range->end, vma->vm_end); | |
1109 | ||
1110 | mm_walk.vma = vma; | |
1111 | mm_walk.mm = vma->vm_mm; | |
1112 | mm_walk.pte_entry = NULL; | |
1113 | mm_walk.test_walk = NULL; | |
1114 | mm_walk.hugetlb_entry = NULL; | |
992de9a8 | 1115 | mm_walk.pud_entry = hmm_vma_walk_pud; |
a3e0d41c JG |
1116 | mm_walk.pmd_entry = hmm_vma_walk_pmd; |
1117 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
63d5066f | 1118 | mm_walk.hugetlb_entry = hmm_vma_walk_hugetlb_entry; |
a3e0d41c JG |
1119 | |
1120 | do { | |
1121 | ret = walk_page_range(start, end, &mm_walk); | |
1122 | start = hmm_vma_walk.last; | |
1123 | ||
1124 | /* Keep trying while the range is valid. */ | |
1125 | } while (ret == -EBUSY && range->valid); | |
1126 | ||
1127 | if (ret) { | |
1128 | unsigned long i; | |
1129 | ||
1130 | i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; | |
1131 | hmm_pfns_clear(range, &range->pfns[i], | |
1132 | hmm_vma_walk.last, range->end); | |
1133 | return ret; | |
1134 | } | |
1135 | start = end; | |
74eee180 | 1136 | |
a3e0d41c | 1137 | } while (start < range->end); |
704f3f2c | 1138 | |
73231612 | 1139 | return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
74eee180 | 1140 | } |
73231612 | 1141 | EXPORT_SYMBOL(hmm_range_fault); |
55c0ece8 JG |
1142 | |
1143 | /** | |
1144 | * hmm_range_dma_map() - hmm_range_fault() and dma map page all in one. | |
1145 | * @range: range being faulted | |
1146 | * @device: device against to dma map page to | |
1147 | * @daddrs: dma address of mapped pages | |
1148 | * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) | |
085ea250 | 1149 | * Return: number of pages mapped on success, -EAGAIN if mmap_sem have been |
55c0ece8 JG |
1150 | * drop and you need to try again, some other error value otherwise |
1151 | * | |
1152 | * Note same usage pattern as hmm_range_fault(). | |
1153 | */ | |
1154 | long hmm_range_dma_map(struct hmm_range *range, | |
1155 | struct device *device, | |
1156 | dma_addr_t *daddrs, | |
1157 | bool block) | |
1158 | { | |
1159 | unsigned long i, npages, mapped; | |
1160 | long ret; | |
1161 | ||
1162 | ret = hmm_range_fault(range, block); | |
1163 | if (ret <= 0) | |
1164 | return ret ? ret : -EBUSY; | |
1165 | ||
1166 | npages = (range->end - range->start) >> PAGE_SHIFT; | |
1167 | for (i = 0, mapped = 0; i < npages; ++i) { | |
1168 | enum dma_data_direction dir = DMA_TO_DEVICE; | |
1169 | struct page *page; | |
1170 | ||
1171 | /* | |
1172 | * FIXME need to update DMA API to provide invalid DMA address | |
1173 | * value instead of a function to test dma address value. This | |
1174 | * would remove lot of dumb code duplicated accross many arch. | |
1175 | * | |
1176 | * For now setting it to 0 here is good enough as the pfns[] | |
1177 | * value is what is use to check what is valid and what isn't. | |
1178 | */ | |
1179 | daddrs[i] = 0; | |
1180 | ||
391aab11 | 1181 | page = hmm_device_entry_to_page(range, range->pfns[i]); |
55c0ece8 JG |
1182 | if (page == NULL) |
1183 | continue; | |
1184 | ||
1185 | /* Check if range is being invalidated */ | |
1186 | if (!range->valid) { | |
1187 | ret = -EBUSY; | |
1188 | goto unmap; | |
1189 | } | |
1190 | ||
1191 | /* If it is read and write than map bi-directional. */ | |
1192 | if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) | |
1193 | dir = DMA_BIDIRECTIONAL; | |
1194 | ||
1195 | daddrs[i] = dma_map_page(device, page, 0, PAGE_SIZE, dir); | |
1196 | if (dma_mapping_error(device, daddrs[i])) { | |
1197 | ret = -EFAULT; | |
1198 | goto unmap; | |
1199 | } | |
1200 | ||
1201 | mapped++; | |
1202 | } | |
1203 | ||
1204 | return mapped; | |
1205 | ||
1206 | unmap: | |
1207 | for (npages = i, i = 0; (i < npages) && mapped; ++i) { | |
1208 | enum dma_data_direction dir = DMA_TO_DEVICE; | |
1209 | struct page *page; | |
1210 | ||
391aab11 | 1211 | page = hmm_device_entry_to_page(range, range->pfns[i]); |
55c0ece8 JG |
1212 | if (page == NULL) |
1213 | continue; | |
1214 | ||
1215 | if (dma_mapping_error(device, daddrs[i])) | |
1216 | continue; | |
1217 | ||
1218 | /* If it is read and write than map bi-directional. */ | |
1219 | if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) | |
1220 | dir = DMA_BIDIRECTIONAL; | |
1221 | ||
1222 | dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir); | |
1223 | mapped--; | |
1224 | } | |
1225 | ||
1226 | return ret; | |
1227 | } | |
1228 | EXPORT_SYMBOL(hmm_range_dma_map); | |
1229 | ||
1230 | /** | |
1231 | * hmm_range_dma_unmap() - unmap range of that was map with hmm_range_dma_map() | |
1232 | * @range: range being unmapped | |
1233 | * @vma: the vma against which the range (optional) | |
1234 | * @device: device against which dma map was done | |
1235 | * @daddrs: dma address of mapped pages | |
1236 | * @dirty: dirty page if it had the write flag set | |
085ea250 | 1237 | * Return: number of page unmapped on success, -EINVAL otherwise |
55c0ece8 JG |
1238 | * |
1239 | * Note that caller MUST abide by mmu notifier or use HMM mirror and abide | |
1240 | * to the sync_cpu_device_pagetables() callback so that it is safe here to | |
1241 | * call set_page_dirty(). Caller must also take appropriate locks to avoid | |
1242 | * concurrent mmu notifier or sync_cpu_device_pagetables() to make progress. | |
1243 | */ | |
1244 | long hmm_range_dma_unmap(struct hmm_range *range, | |
1245 | struct vm_area_struct *vma, | |
1246 | struct device *device, | |
1247 | dma_addr_t *daddrs, | |
1248 | bool dirty) | |
1249 | { | |
1250 | unsigned long i, npages; | |
1251 | long cpages = 0; | |
1252 | ||
1253 | /* Sanity check. */ | |
1254 | if (range->end <= range->start) | |
1255 | return -EINVAL; | |
1256 | if (!daddrs) | |
1257 | return -EINVAL; | |
1258 | if (!range->pfns) | |
1259 | return -EINVAL; | |
1260 | ||
1261 | npages = (range->end - range->start) >> PAGE_SHIFT; | |
1262 | for (i = 0; i < npages; ++i) { | |
1263 | enum dma_data_direction dir = DMA_TO_DEVICE; | |
1264 | struct page *page; | |
1265 | ||
391aab11 | 1266 | page = hmm_device_entry_to_page(range, range->pfns[i]); |
55c0ece8 JG |
1267 | if (page == NULL) |
1268 | continue; | |
1269 | ||
1270 | /* If it is read and write than map bi-directional. */ | |
1271 | if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) { | |
1272 | dir = DMA_BIDIRECTIONAL; | |
1273 | ||
1274 | /* | |
1275 | * See comments in function description on why it is | |
1276 | * safe here to call set_page_dirty() | |
1277 | */ | |
1278 | if (dirty) | |
1279 | set_page_dirty(page); | |
1280 | } | |
1281 | ||
1282 | /* Unmap and clear pfns/dma address */ | |
1283 | dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir); | |
1284 | range->pfns[i] = range->values[HMM_PFN_NONE]; | |
1285 | /* FIXME see comments in hmm_vma_dma_map() */ | |
1286 | daddrs[i] = 0; | |
1287 | cpages++; | |
1288 | } | |
1289 | ||
1290 | return cpages; | |
1291 | } | |
1292 | EXPORT_SYMBOL(hmm_range_dma_unmap); | |
c0b12405 | 1293 | #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ |
4ef589dc JG |
1294 | |
1295 | ||
df6ad698 | 1296 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) |
4ef589dc JG |
1297 | struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma, |
1298 | unsigned long addr) | |
1299 | { | |
1300 | struct page *page; | |
1301 | ||
1302 | page = alloc_page_vma(GFP_HIGHUSER, vma, addr); | |
1303 | if (!page) | |
1304 | return NULL; | |
1305 | lock_page(page); | |
1306 | return page; | |
1307 | } | |
1308 | EXPORT_SYMBOL(hmm_vma_alloc_locked_page); | |
1309 | ||
1310 | ||
1311 | static void hmm_devmem_ref_release(struct percpu_ref *ref) | |
1312 | { | |
1313 | struct hmm_devmem *devmem; | |
1314 | ||
1315 | devmem = container_of(ref, struct hmm_devmem, ref); | |
1316 | complete(&devmem->completion); | |
1317 | } | |
1318 | ||
1319 | static void hmm_devmem_ref_exit(void *data) | |
1320 | { | |
1321 | struct percpu_ref *ref = data; | |
1322 | struct hmm_devmem *devmem; | |
1323 | ||
1324 | devmem = container_of(ref, struct hmm_devmem, ref); | |
bbecd94e | 1325 | wait_for_completion(&devmem->completion); |
4ef589dc | 1326 | percpu_ref_exit(ref); |
4ef589dc JG |
1327 | } |
1328 | ||
bbecd94e | 1329 | static void hmm_devmem_ref_kill(struct percpu_ref *ref) |
4ef589dc | 1330 | { |
4ef589dc | 1331 | percpu_ref_kill(ref); |
4ef589dc JG |
1332 | } |
1333 | ||
b57e622e | 1334 | static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma, |
4ef589dc JG |
1335 | unsigned long addr, |
1336 | const struct page *page, | |
1337 | unsigned int flags, | |
1338 | pmd_t *pmdp) | |
1339 | { | |
1340 | struct hmm_devmem *devmem = page->pgmap->data; | |
1341 | ||
1342 | return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); | |
1343 | } | |
1344 | ||
1345 | static void hmm_devmem_free(struct page *page, void *data) | |
1346 | { | |
1347 | struct hmm_devmem *devmem = data; | |
1348 | ||
2fa147bd DW |
1349 | page->mapping = NULL; |
1350 | ||
4ef589dc JG |
1351 | devmem->ops->free(devmem, page); |
1352 | } | |
1353 | ||
4ef589dc JG |
1354 | /* |
1355 | * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory | |
1356 | * | |
1357 | * @ops: memory event device driver callback (see struct hmm_devmem_ops) | |
1358 | * @device: device struct to bind the resource too | |
1359 | * @size: size in bytes of the device memory to add | |
085ea250 | 1360 | * Return: pointer to new hmm_devmem struct ERR_PTR otherwise |
4ef589dc JG |
1361 | * |
1362 | * This function first finds an empty range of physical address big enough to | |
1363 | * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which | |
1364 | * in turn allocates struct pages. It does not do anything beyond that; all | |
1365 | * events affecting the memory will go through the various callbacks provided | |
1366 | * by hmm_devmem_ops struct. | |
1367 | * | |
1368 | * Device driver should call this function during device initialization and | |
1369 | * is then responsible of memory management. HMM only provides helpers. | |
1370 | */ | |
1371 | struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, | |
1372 | struct device *device, | |
1373 | unsigned long size) | |
1374 | { | |
1375 | struct hmm_devmem *devmem; | |
1376 | resource_size_t addr; | |
bbecd94e | 1377 | void *result; |
4ef589dc JG |
1378 | int ret; |
1379 | ||
e7638488 | 1380 | dev_pagemap_get_ops(); |
4ef589dc | 1381 | |
58ef15b7 | 1382 | devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
4ef589dc JG |
1383 | if (!devmem) |
1384 | return ERR_PTR(-ENOMEM); | |
1385 | ||
1386 | init_completion(&devmem->completion); | |
1387 | devmem->pfn_first = -1UL; | |
1388 | devmem->pfn_last = -1UL; | |
1389 | devmem->resource = NULL; | |
1390 | devmem->device = device; | |
1391 | devmem->ops = ops; | |
1392 | ||
1393 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1394 | 0, GFP_KERNEL); | |
1395 | if (ret) | |
58ef15b7 | 1396 | return ERR_PTR(ret); |
4ef589dc | 1397 | |
58ef15b7 | 1398 | ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref); |
4ef589dc | 1399 | if (ret) |
58ef15b7 | 1400 | return ERR_PTR(ret); |
4ef589dc JG |
1401 | |
1402 | size = ALIGN(size, PA_SECTION_SIZE); | |
1403 | addr = min((unsigned long)iomem_resource.end, | |
1404 | (1UL << MAX_PHYSMEM_BITS) - 1); | |
1405 | addr = addr - size + 1UL; | |
1406 | ||
1407 | /* | |
1408 | * FIXME add a new helper to quickly walk resource tree and find free | |
1409 | * range | |
1410 | * | |
1411 | * FIXME what about ioport_resource resource ? | |
1412 | */ | |
1413 | for (; addr > size && addr >= iomem_resource.start; addr -= size) { | |
1414 | ret = region_intersects(addr, size, 0, IORES_DESC_NONE); | |
1415 | if (ret != REGION_DISJOINT) | |
1416 | continue; | |
1417 | ||
1418 | devmem->resource = devm_request_mem_region(device, addr, size, | |
1419 | dev_name(device)); | |
58ef15b7 DW |
1420 | if (!devmem->resource) |
1421 | return ERR_PTR(-ENOMEM); | |
4ef589dc JG |
1422 | break; |
1423 | } | |
58ef15b7 DW |
1424 | if (!devmem->resource) |
1425 | return ERR_PTR(-ERANGE); | |
4ef589dc JG |
1426 | |
1427 | devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; | |
1428 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1429 | devmem->pfn_last = devmem->pfn_first + | |
1430 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
063a7d1d | 1431 | devmem->page_fault = hmm_devmem_fault; |
4ef589dc | 1432 | |
bbecd94e DW |
1433 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; |
1434 | devmem->pagemap.res = *devmem->resource; | |
bbecd94e DW |
1435 | devmem->pagemap.page_free = hmm_devmem_free; |
1436 | devmem->pagemap.altmap_valid = false; | |
1437 | devmem->pagemap.ref = &devmem->ref; | |
1438 | devmem->pagemap.data = devmem; | |
1439 | devmem->pagemap.kill = hmm_devmem_ref_kill; | |
4ef589dc | 1440 | |
bbecd94e DW |
1441 | result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
1442 | if (IS_ERR(result)) | |
1443 | return result; | |
4ef589dc | 1444 | return devmem; |
4ef589dc | 1445 | } |
02917e9f | 1446 | EXPORT_SYMBOL_GPL(hmm_devmem_add); |
4ef589dc | 1447 | |
d3df0a42 JG |
1448 | struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, |
1449 | struct device *device, | |
1450 | struct resource *res) | |
1451 | { | |
1452 | struct hmm_devmem *devmem; | |
bbecd94e | 1453 | void *result; |
d3df0a42 JG |
1454 | int ret; |
1455 | ||
1456 | if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) | |
1457 | return ERR_PTR(-EINVAL); | |
1458 | ||
e7638488 | 1459 | dev_pagemap_get_ops(); |
d3df0a42 | 1460 | |
58ef15b7 | 1461 | devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
d3df0a42 JG |
1462 | if (!devmem) |
1463 | return ERR_PTR(-ENOMEM); | |
1464 | ||
1465 | init_completion(&devmem->completion); | |
1466 | devmem->pfn_first = -1UL; | |
1467 | devmem->pfn_last = -1UL; | |
1468 | devmem->resource = res; | |
1469 | devmem->device = device; | |
1470 | devmem->ops = ops; | |
1471 | ||
1472 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1473 | 0, GFP_KERNEL); | |
1474 | if (ret) | |
58ef15b7 | 1475 | return ERR_PTR(ret); |
d3df0a42 | 1476 | |
58ef15b7 DW |
1477 | ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, |
1478 | &devmem->ref); | |
d3df0a42 | 1479 | if (ret) |
58ef15b7 | 1480 | return ERR_PTR(ret); |
d3df0a42 JG |
1481 | |
1482 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1483 | devmem->pfn_last = devmem->pfn_first + | |
1484 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
063a7d1d | 1485 | devmem->page_fault = hmm_devmem_fault; |
d3df0a42 | 1486 | |
bbecd94e DW |
1487 | devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; |
1488 | devmem->pagemap.res = *devmem->resource; | |
bbecd94e DW |
1489 | devmem->pagemap.page_free = hmm_devmem_free; |
1490 | devmem->pagemap.altmap_valid = false; | |
1491 | devmem->pagemap.ref = &devmem->ref; | |
1492 | devmem->pagemap.data = devmem; | |
1493 | devmem->pagemap.kill = hmm_devmem_ref_kill; | |
d3df0a42 | 1494 | |
bbecd94e DW |
1495 | result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
1496 | if (IS_ERR(result)) | |
1497 | return result; | |
d3df0a42 | 1498 | return devmem; |
d3df0a42 | 1499 | } |
02917e9f | 1500 | EXPORT_SYMBOL_GPL(hmm_devmem_add_resource); |
d3df0a42 | 1501 | |
858b54da JG |
1502 | /* |
1503 | * A device driver that wants to handle multiple devices memory through a | |
1504 | * single fake device can use hmm_device to do so. This is purely a helper | |
1505 | * and it is not needed to make use of any HMM functionality. | |
1506 | */ | |
1507 | #define HMM_DEVICE_MAX 256 | |
1508 | ||
1509 | static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); | |
1510 | static DEFINE_SPINLOCK(hmm_device_lock); | |
1511 | static struct class *hmm_device_class; | |
1512 | static dev_t hmm_device_devt; | |
1513 | ||
1514 | static void hmm_device_release(struct device *device) | |
1515 | { | |
1516 | struct hmm_device *hmm_device; | |
1517 | ||
1518 | hmm_device = container_of(device, struct hmm_device, device); | |
1519 | spin_lock(&hmm_device_lock); | |
1520 | clear_bit(hmm_device->minor, hmm_device_mask); | |
1521 | spin_unlock(&hmm_device_lock); | |
1522 | ||
1523 | kfree(hmm_device); | |
1524 | } | |
1525 | ||
1526 | struct hmm_device *hmm_device_new(void *drvdata) | |
1527 | { | |
1528 | struct hmm_device *hmm_device; | |
1529 | ||
1530 | hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); | |
1531 | if (!hmm_device) | |
1532 | return ERR_PTR(-ENOMEM); | |
1533 | ||
1534 | spin_lock(&hmm_device_lock); | |
1535 | hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); | |
1536 | if (hmm_device->minor >= HMM_DEVICE_MAX) { | |
1537 | spin_unlock(&hmm_device_lock); | |
1538 | kfree(hmm_device); | |
1539 | return ERR_PTR(-EBUSY); | |
1540 | } | |
1541 | set_bit(hmm_device->minor, hmm_device_mask); | |
1542 | spin_unlock(&hmm_device_lock); | |
1543 | ||
1544 | dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); | |
1545 | hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), | |
1546 | hmm_device->minor); | |
1547 | hmm_device->device.release = hmm_device_release; | |
1548 | dev_set_drvdata(&hmm_device->device, drvdata); | |
1549 | hmm_device->device.class = hmm_device_class; | |
1550 | device_initialize(&hmm_device->device); | |
1551 | ||
1552 | return hmm_device; | |
1553 | } | |
1554 | EXPORT_SYMBOL(hmm_device_new); | |
1555 | ||
1556 | void hmm_device_put(struct hmm_device *hmm_device) | |
1557 | { | |
1558 | put_device(&hmm_device->device); | |
1559 | } | |
1560 | EXPORT_SYMBOL(hmm_device_put); | |
1561 | ||
1562 | static int __init hmm_init(void) | |
1563 | { | |
1564 | int ret; | |
1565 | ||
1566 | ret = alloc_chrdev_region(&hmm_device_devt, 0, | |
1567 | HMM_DEVICE_MAX, | |
1568 | "hmm_device"); | |
1569 | if (ret) | |
1570 | return ret; | |
1571 | ||
1572 | hmm_device_class = class_create(THIS_MODULE, "hmm_device"); | |
1573 | if (IS_ERR(hmm_device_class)) { | |
1574 | unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); | |
1575 | return PTR_ERR(hmm_device_class); | |
1576 | } | |
1577 | return 0; | |
1578 | } | |
1579 | ||
1580 | device_initcall(hmm_init); | |
df6ad698 | 1581 | #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ |