Commit | Line | Data |
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133ff0ea JG |
1 | /* |
2 | * Copyright 2013 Red Hat Inc. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * Authors: Jérôme Glisse <jglisse@redhat.com> | |
15 | */ | |
16 | /* | |
17 | * Refer to include/linux/hmm.h for information about heterogeneous memory | |
18 | * management or HMM for short. | |
19 | */ | |
20 | #include <linux/mm.h> | |
21 | #include <linux/hmm.h> | |
858b54da | 22 | #include <linux/init.h> |
da4c3c73 JG |
23 | #include <linux/rmap.h> |
24 | #include <linux/swap.h> | |
133ff0ea JG |
25 | #include <linux/slab.h> |
26 | #include <linux/sched.h> | |
4ef589dc JG |
27 | #include <linux/mmzone.h> |
28 | #include <linux/pagemap.h> | |
da4c3c73 JG |
29 | #include <linux/swapops.h> |
30 | #include <linux/hugetlb.h> | |
4ef589dc | 31 | #include <linux/memremap.h> |
7b2d55d2 | 32 | #include <linux/jump_label.h> |
c0b12405 | 33 | #include <linux/mmu_notifier.h> |
4ef589dc JG |
34 | #include <linux/memory_hotplug.h> |
35 | ||
36 | #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) | |
133ff0ea | 37 | |
6b368cd4 | 38 | #if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC) |
7b2d55d2 JG |
39 | /* |
40 | * Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h | |
41 | */ | |
42 | DEFINE_STATIC_KEY_FALSE(device_private_key); | |
43 | EXPORT_SYMBOL(device_private_key); | |
6b368cd4 | 44 | #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ |
7b2d55d2 JG |
45 | |
46 | ||
6b368cd4 | 47 | #if IS_ENABLED(CONFIG_HMM_MIRROR) |
c0b12405 JG |
48 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops; |
49 | ||
133ff0ea JG |
50 | /* |
51 | * struct hmm - HMM per mm struct | |
52 | * | |
53 | * @mm: mm struct this HMM struct is bound to | |
da4c3c73 | 54 | * @lock: lock protecting ranges list |
c0b12405 | 55 | * @sequence: we track updates to the CPU page table with a sequence number |
da4c3c73 | 56 | * @ranges: list of range being snapshotted |
c0b12405 JG |
57 | * @mirrors: list of mirrors for this mm |
58 | * @mmu_notifier: mmu notifier to track updates to CPU page table | |
59 | * @mirrors_sem: read/write semaphore protecting the mirrors list | |
133ff0ea JG |
60 | */ |
61 | struct hmm { | |
62 | struct mm_struct *mm; | |
da4c3c73 | 63 | spinlock_t lock; |
c0b12405 | 64 | atomic_t sequence; |
da4c3c73 | 65 | struct list_head ranges; |
c0b12405 JG |
66 | struct list_head mirrors; |
67 | struct mmu_notifier mmu_notifier; | |
68 | struct rw_semaphore mirrors_sem; | |
133ff0ea JG |
69 | }; |
70 | ||
71 | /* | |
72 | * hmm_register - register HMM against an mm (HMM internal) | |
73 | * | |
74 | * @mm: mm struct to attach to | |
75 | * | |
76 | * This is not intended to be used directly by device drivers. It allocates an | |
77 | * HMM struct if mm does not have one, and initializes it. | |
78 | */ | |
79 | static struct hmm *hmm_register(struct mm_struct *mm) | |
80 | { | |
c0b12405 JG |
81 | struct hmm *hmm = READ_ONCE(mm->hmm); |
82 | bool cleanup = false; | |
133ff0ea JG |
83 | |
84 | /* | |
85 | * The hmm struct can only be freed once the mm_struct goes away, | |
86 | * hence we should always have pre-allocated an new hmm struct | |
87 | * above. | |
88 | */ | |
c0b12405 JG |
89 | if (hmm) |
90 | return hmm; | |
91 | ||
92 | hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); | |
93 | if (!hmm) | |
94 | return NULL; | |
95 | INIT_LIST_HEAD(&hmm->mirrors); | |
96 | init_rwsem(&hmm->mirrors_sem); | |
97 | atomic_set(&hmm->sequence, 0); | |
98 | hmm->mmu_notifier.ops = NULL; | |
da4c3c73 JG |
99 | INIT_LIST_HEAD(&hmm->ranges); |
100 | spin_lock_init(&hmm->lock); | |
c0b12405 JG |
101 | hmm->mm = mm; |
102 | ||
103 | /* | |
104 | * We should only get here if hold the mmap_sem in write mode ie on | |
105 | * registration of first mirror through hmm_mirror_register() | |
106 | */ | |
107 | hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops; | |
108 | if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) { | |
109 | kfree(hmm); | |
110 | return NULL; | |
111 | } | |
112 | ||
113 | spin_lock(&mm->page_table_lock); | |
114 | if (!mm->hmm) | |
115 | mm->hmm = hmm; | |
116 | else | |
117 | cleanup = true; | |
118 | spin_unlock(&mm->page_table_lock); | |
119 | ||
120 | if (cleanup) { | |
121 | mmu_notifier_unregister(&hmm->mmu_notifier, mm); | |
122 | kfree(hmm); | |
123 | } | |
124 | ||
133ff0ea JG |
125 | return mm->hmm; |
126 | } | |
127 | ||
128 | void hmm_mm_destroy(struct mm_struct *mm) | |
129 | { | |
130 | kfree(mm->hmm); | |
131 | } | |
c0b12405 | 132 | |
c0b12405 JG |
133 | static void hmm_invalidate_range(struct hmm *hmm, |
134 | enum hmm_update_type action, | |
135 | unsigned long start, | |
136 | unsigned long end) | |
137 | { | |
138 | struct hmm_mirror *mirror; | |
da4c3c73 JG |
139 | struct hmm_range *range; |
140 | ||
141 | spin_lock(&hmm->lock); | |
142 | list_for_each_entry(range, &hmm->ranges, list) { | |
143 | unsigned long addr, idx, npages; | |
144 | ||
145 | if (end < range->start || start >= range->end) | |
146 | continue; | |
147 | ||
148 | range->valid = false; | |
149 | addr = max(start, range->start); | |
150 | idx = (addr - range->start) >> PAGE_SHIFT; | |
151 | npages = (min(range->end, end) - addr) >> PAGE_SHIFT; | |
152 | memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages); | |
153 | } | |
154 | spin_unlock(&hmm->lock); | |
c0b12405 JG |
155 | |
156 | down_read(&hmm->mirrors_sem); | |
157 | list_for_each_entry(mirror, &hmm->mirrors, list) | |
158 | mirror->ops->sync_cpu_device_pagetables(mirror, action, | |
159 | start, end); | |
160 | up_read(&hmm->mirrors_sem); | |
161 | } | |
162 | ||
e1401513 RC |
163 | static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) |
164 | { | |
165 | struct hmm_mirror *mirror; | |
166 | struct hmm *hmm = mm->hmm; | |
167 | ||
168 | down_write(&hmm->mirrors_sem); | |
169 | mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror, | |
170 | list); | |
171 | while (mirror) { | |
172 | list_del_init(&mirror->list); | |
173 | if (mirror->ops->release) { | |
174 | /* | |
175 | * Drop mirrors_sem so callback can wait on any pending | |
176 | * work that might itself trigger mmu_notifier callback | |
177 | * and thus would deadlock with us. | |
178 | */ | |
179 | up_write(&hmm->mirrors_sem); | |
180 | mirror->ops->release(mirror); | |
181 | down_write(&hmm->mirrors_sem); | |
182 | } | |
183 | mirror = list_first_entry_or_null(&hmm->mirrors, | |
184 | struct hmm_mirror, list); | |
185 | } | |
186 | up_write(&hmm->mirrors_sem); | |
187 | } | |
188 | ||
c0b12405 JG |
189 | static void hmm_invalidate_range_start(struct mmu_notifier *mn, |
190 | struct mm_struct *mm, | |
191 | unsigned long start, | |
192 | unsigned long end) | |
193 | { | |
194 | struct hmm *hmm = mm->hmm; | |
195 | ||
196 | VM_BUG_ON(!hmm); | |
197 | ||
198 | atomic_inc(&hmm->sequence); | |
199 | } | |
200 | ||
201 | static void hmm_invalidate_range_end(struct mmu_notifier *mn, | |
202 | struct mm_struct *mm, | |
203 | unsigned long start, | |
204 | unsigned long end) | |
205 | { | |
206 | struct hmm *hmm = mm->hmm; | |
207 | ||
208 | VM_BUG_ON(!hmm); | |
209 | ||
210 | hmm_invalidate_range(mm->hmm, HMM_UPDATE_INVALIDATE, start, end); | |
211 | } | |
212 | ||
213 | static const struct mmu_notifier_ops hmm_mmu_notifier_ops = { | |
e1401513 | 214 | .release = hmm_release, |
c0b12405 JG |
215 | .invalidate_range_start = hmm_invalidate_range_start, |
216 | .invalidate_range_end = hmm_invalidate_range_end, | |
217 | }; | |
218 | ||
219 | /* | |
220 | * hmm_mirror_register() - register a mirror against an mm | |
221 | * | |
222 | * @mirror: new mirror struct to register | |
223 | * @mm: mm to register against | |
224 | * | |
225 | * To start mirroring a process address space, the device driver must register | |
226 | * an HMM mirror struct. | |
227 | * | |
228 | * THE mm->mmap_sem MUST BE HELD IN WRITE MODE ! | |
229 | */ | |
230 | int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) | |
231 | { | |
232 | /* Sanity check */ | |
233 | if (!mm || !mirror || !mirror->ops) | |
234 | return -EINVAL; | |
235 | ||
c01cbba2 | 236 | again: |
c0b12405 JG |
237 | mirror->hmm = hmm_register(mm); |
238 | if (!mirror->hmm) | |
239 | return -ENOMEM; | |
240 | ||
241 | down_write(&mirror->hmm->mirrors_sem); | |
c01cbba2 JG |
242 | if (mirror->hmm->mm == NULL) { |
243 | /* | |
244 | * A racing hmm_mirror_unregister() is about to destroy the hmm | |
245 | * struct. Try again to allocate a new one. | |
246 | */ | |
247 | up_write(&mirror->hmm->mirrors_sem); | |
248 | mirror->hmm = NULL; | |
249 | goto again; | |
250 | } else { | |
251 | list_add(&mirror->list, &mirror->hmm->mirrors); | |
252 | up_write(&mirror->hmm->mirrors_sem); | |
253 | } | |
c0b12405 JG |
254 | |
255 | return 0; | |
256 | } | |
257 | EXPORT_SYMBOL(hmm_mirror_register); | |
258 | ||
259 | /* | |
260 | * hmm_mirror_unregister() - unregister a mirror | |
261 | * | |
262 | * @mirror: new mirror struct to register | |
263 | * | |
264 | * Stop mirroring a process address space, and cleanup. | |
265 | */ | |
266 | void hmm_mirror_unregister(struct hmm_mirror *mirror) | |
267 | { | |
c01cbba2 JG |
268 | bool should_unregister = false; |
269 | struct mm_struct *mm; | |
270 | struct hmm *hmm; | |
271 | ||
272 | if (mirror->hmm == NULL) | |
273 | return; | |
c0b12405 | 274 | |
c01cbba2 | 275 | hmm = mirror->hmm; |
c0b12405 | 276 | down_write(&hmm->mirrors_sem); |
e1401513 | 277 | list_del_init(&mirror->list); |
c01cbba2 JG |
278 | should_unregister = list_empty(&hmm->mirrors); |
279 | mirror->hmm = NULL; | |
280 | mm = hmm->mm; | |
281 | hmm->mm = NULL; | |
c0b12405 | 282 | up_write(&hmm->mirrors_sem); |
c01cbba2 JG |
283 | |
284 | if (!should_unregister || mm == NULL) | |
285 | return; | |
286 | ||
287 | spin_lock(&mm->page_table_lock); | |
288 | if (mm->hmm == hmm) | |
289 | mm->hmm = NULL; | |
290 | spin_unlock(&mm->page_table_lock); | |
291 | ||
292 | mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm); | |
293 | kfree(hmm); | |
c0b12405 JG |
294 | } |
295 | EXPORT_SYMBOL(hmm_mirror_unregister); | |
da4c3c73 | 296 | |
74eee180 JG |
297 | struct hmm_vma_walk { |
298 | struct hmm_range *range; | |
299 | unsigned long last; | |
300 | bool fault; | |
301 | bool block; | |
302 | bool write; | |
303 | }; | |
304 | ||
305 | static int hmm_vma_do_fault(struct mm_walk *walk, | |
306 | unsigned long addr, | |
ff05c0c6 | 307 | uint64_t *pfn) |
74eee180 JG |
308 | { |
309 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE; | |
310 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
311 | struct vm_area_struct *vma = walk->vma; | |
312 | int r; | |
313 | ||
314 | flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; | |
315 | flags |= hmm_vma_walk->write ? FAULT_FLAG_WRITE : 0; | |
316 | r = handle_mm_fault(vma, addr, flags); | |
317 | if (r & VM_FAULT_RETRY) | |
318 | return -EBUSY; | |
319 | if (r & VM_FAULT_ERROR) { | |
320 | *pfn = HMM_PFN_ERROR; | |
321 | return -EFAULT; | |
322 | } | |
323 | ||
324 | return -EAGAIN; | |
325 | } | |
326 | ||
da4c3c73 JG |
327 | static int hmm_pfns_bad(unsigned long addr, |
328 | unsigned long end, | |
329 | struct mm_walk *walk) | |
330 | { | |
c719547f JG |
331 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
332 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 333 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
334 | unsigned long i; |
335 | ||
336 | i = (addr - range->start) >> PAGE_SHIFT; | |
337 | for (; addr < end; addr += PAGE_SIZE, i++) | |
338 | pfns[i] = HMM_PFN_ERROR; | |
339 | ||
340 | return 0; | |
341 | } | |
342 | ||
5504ed29 JG |
343 | /* |
344 | * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) | |
345 | * @start: range virtual start address (inclusive) | |
346 | * @end: range virtual end address (exclusive) | |
347 | * @walk: mm_walk structure | |
348 | * Returns: 0 on success, -EAGAIN after page fault, or page fault error | |
349 | * | |
350 | * This function will be called whenever pmd_none() or pte_none() returns true, | |
351 | * or whenever there is no page directory covering the virtual address range. | |
352 | */ | |
da4c3c73 JG |
353 | static int hmm_vma_walk_hole(unsigned long addr, |
354 | unsigned long end, | |
355 | struct mm_walk *walk) | |
356 | { | |
74eee180 JG |
357 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
358 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 359 | uint64_t *pfns = range->pfns; |
da4c3c73 JG |
360 | unsigned long i; |
361 | ||
74eee180 | 362 | hmm_vma_walk->last = addr; |
da4c3c73 | 363 | i = (addr - range->start) >> PAGE_SHIFT; |
74eee180 | 364 | for (; addr < end; addr += PAGE_SIZE, i++) { |
da4c3c73 | 365 | pfns[i] = 0; |
74eee180 JG |
366 | if (hmm_vma_walk->fault) { |
367 | int ret; | |
da4c3c73 | 368 | |
74eee180 JG |
369 | ret = hmm_vma_do_fault(walk, addr, &pfns[i]); |
370 | if (ret != -EAGAIN) | |
371 | return ret; | |
372 | } | |
373 | } | |
374 | ||
375 | return hmm_vma_walk->fault ? -EAGAIN : 0; | |
da4c3c73 JG |
376 | } |
377 | ||
53f5c3f4 JG |
378 | static int hmm_vma_handle_pmd(struct mm_walk *walk, |
379 | unsigned long addr, | |
380 | unsigned long end, | |
381 | uint64_t *pfns, | |
382 | pmd_t pmd) | |
383 | { | |
384 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
385 | unsigned long pfn, i; | |
386 | uint64_t flag = 0; | |
387 | ||
388 | if (pmd_protnone(pmd)) | |
389 | return hmm_vma_walk_hole(addr, end, walk); | |
390 | ||
391 | if ((hmm_vma_walk->fault & hmm_vma_walk->write) && !pmd_write(pmd)) | |
392 | return hmm_vma_walk_hole(addr, end, walk); | |
393 | ||
394 | pfn = pmd_pfn(pmd) + pte_index(addr); | |
395 | flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0; | |
396 | for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) | |
397 | pfns[i] = hmm_pfn_from_pfn(pfn) | flag; | |
398 | hmm_vma_walk->last = end; | |
399 | return 0; | |
400 | } | |
401 | ||
402 | static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, | |
403 | unsigned long end, pmd_t *pmdp, pte_t *ptep, | |
404 | uint64_t *pfn) | |
405 | { | |
406 | struct hmm_vma_walk *hmm_vma_walk = walk->private; | |
407 | struct vm_area_struct *vma = walk->vma; | |
408 | pte_t pte = *ptep; | |
409 | ||
410 | *pfn = 0; | |
411 | ||
412 | if (pte_none(pte)) { | |
413 | *pfn = 0; | |
414 | if (hmm_vma_walk->fault) | |
415 | goto fault; | |
416 | return 0; | |
417 | } | |
418 | ||
419 | if (!pte_present(pte)) { | |
420 | swp_entry_t entry = pte_to_swp_entry(pte); | |
421 | ||
422 | if (!non_swap_entry(entry)) { | |
423 | if (hmm_vma_walk->fault) | |
424 | goto fault; | |
425 | return 0; | |
426 | } | |
427 | ||
428 | /* | |
429 | * This is a special swap entry, ignore migration, use | |
430 | * device and report anything else as error. | |
431 | */ | |
432 | if (is_device_private_entry(entry)) { | |
433 | *pfn = hmm_pfn_from_pfn(swp_offset(entry)); | |
434 | if (is_write_device_private_entry(entry)) { | |
435 | *pfn |= HMM_PFN_WRITE; | |
436 | } else if ((hmm_vma_walk->fault & hmm_vma_walk->write)) | |
437 | goto fault; | |
438 | *pfn |= HMM_PFN_DEVICE_PRIVATE; | |
439 | return 0; | |
440 | } | |
441 | ||
442 | if (is_migration_entry(entry)) { | |
443 | if (hmm_vma_walk->fault) { | |
444 | pte_unmap(ptep); | |
445 | hmm_vma_walk->last = addr; | |
446 | migration_entry_wait(vma->vm_mm, | |
447 | pmdp, addr); | |
448 | return -EAGAIN; | |
449 | } | |
450 | return 0; | |
451 | } | |
452 | ||
453 | /* Report error for everything else */ | |
454 | *pfn = HMM_PFN_ERROR; | |
455 | return -EFAULT; | |
456 | } | |
457 | ||
458 | if ((hmm_vma_walk->fault & hmm_vma_walk->write) && !pte_write(pte)) | |
459 | goto fault; | |
460 | ||
461 | *pfn = hmm_pfn_from_pfn(pte_pfn(pte)); | |
462 | *pfn |= pte_write(pte) ? HMM_PFN_WRITE : 0; | |
463 | return 0; | |
464 | ||
465 | fault: | |
466 | pte_unmap(ptep); | |
467 | /* Fault any virtual address we were asked to fault */ | |
468 | return hmm_vma_walk_hole(addr, end, walk); | |
469 | } | |
470 | ||
da4c3c73 JG |
471 | static int hmm_vma_walk_pmd(pmd_t *pmdp, |
472 | unsigned long start, | |
473 | unsigned long end, | |
474 | struct mm_walk *walk) | |
475 | { | |
74eee180 JG |
476 | struct hmm_vma_walk *hmm_vma_walk = walk->private; |
477 | struct hmm_range *range = hmm_vma_walk->range; | |
ff05c0c6 | 478 | uint64_t *pfns = range->pfns; |
da4c3c73 | 479 | unsigned long addr = start, i; |
da4c3c73 JG |
480 | pte_t *ptep; |
481 | ||
482 | i = (addr - range->start) >> PAGE_SHIFT; | |
da4c3c73 JG |
483 | |
484 | again: | |
485 | if (pmd_none(*pmdp)) | |
486 | return hmm_vma_walk_hole(start, end, walk); | |
487 | ||
53f5c3f4 | 488 | if (pmd_huge(*pmdp) && (range->vma->vm_flags & VM_HUGETLB)) |
da4c3c73 JG |
489 | return hmm_pfns_bad(start, end, walk); |
490 | ||
491 | if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) { | |
da4c3c73 JG |
492 | pmd_t pmd; |
493 | ||
494 | /* | |
495 | * No need to take pmd_lock here, even if some other threads | |
496 | * is splitting the huge pmd we will get that event through | |
497 | * mmu_notifier callback. | |
498 | * | |
499 | * So just read pmd value and check again its a transparent | |
500 | * huge or device mapping one and compute corresponding pfn | |
501 | * values. | |
502 | */ | |
503 | pmd = pmd_read_atomic(pmdp); | |
504 | barrier(); | |
505 | if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) | |
506 | goto again; | |
74eee180 | 507 | |
53f5c3f4 | 508 | return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd); |
da4c3c73 JG |
509 | } |
510 | ||
511 | if (pmd_bad(*pmdp)) | |
512 | return hmm_pfns_bad(start, end, walk); | |
513 | ||
514 | ptep = pte_offset_map(pmdp, addr); | |
515 | for (; addr < end; addr += PAGE_SIZE, ptep++, i++) { | |
53f5c3f4 | 516 | int r; |
74eee180 | 517 | |
53f5c3f4 JG |
518 | r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]); |
519 | if (r) { | |
520 | /* hmm_vma_handle_pte() did unmap pte directory */ | |
521 | hmm_vma_walk->last = addr; | |
522 | return r; | |
74eee180 | 523 | } |
da4c3c73 JG |
524 | } |
525 | pte_unmap(ptep - 1); | |
526 | ||
53f5c3f4 | 527 | hmm_vma_walk->last = addr; |
da4c3c73 JG |
528 | return 0; |
529 | } | |
530 | ||
33cd47dc JG |
531 | static void hmm_pfns_clear(uint64_t *pfns, |
532 | unsigned long addr, | |
533 | unsigned long end) | |
534 | { | |
535 | for (; addr < end; addr += PAGE_SIZE, pfns++) | |
536 | *pfns = 0; | |
537 | } | |
538 | ||
855ce7d2 JG |
539 | static void hmm_pfns_special(struct hmm_range *range) |
540 | { | |
541 | unsigned long addr = range->start, i = 0; | |
542 | ||
543 | for (; addr < range->end; addr += PAGE_SIZE, i++) | |
544 | range->pfns[i] = HMM_PFN_SPECIAL; | |
545 | } | |
546 | ||
da4c3c73 JG |
547 | /* |
548 | * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses | |
08232a45 | 549 | * @range: range being snapshotted |
86586a41 JG |
550 | * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid |
551 | * vma permission, 0 success | |
da4c3c73 JG |
552 | * |
553 | * This snapshots the CPU page table for a range of virtual addresses. Snapshot | |
554 | * validity is tracked by range struct. See hmm_vma_range_done() for further | |
555 | * information. | |
556 | * | |
557 | * The range struct is initialized here. It tracks the CPU page table, but only | |
558 | * if the function returns success (0), in which case the caller must then call | |
559 | * hmm_vma_range_done() to stop CPU page table update tracking on this range. | |
560 | * | |
561 | * NOT CALLING hmm_vma_range_done() IF FUNCTION RETURNS 0 WILL LEAD TO SERIOUS | |
562 | * MEMORY CORRUPTION ! YOU HAVE BEEN WARNED ! | |
563 | */ | |
08232a45 | 564 | int hmm_vma_get_pfns(struct hmm_range *range) |
da4c3c73 | 565 | { |
08232a45 | 566 | struct vm_area_struct *vma = range->vma; |
74eee180 | 567 | struct hmm_vma_walk hmm_vma_walk; |
da4c3c73 JG |
568 | struct mm_walk mm_walk; |
569 | struct hmm *hmm; | |
570 | ||
da4c3c73 | 571 | /* Sanity check, this really should not happen ! */ |
08232a45 | 572 | if (range->start < vma->vm_start || range->start >= vma->vm_end) |
da4c3c73 | 573 | return -EINVAL; |
08232a45 | 574 | if (range->end < vma->vm_start || range->end > vma->vm_end) |
da4c3c73 JG |
575 | return -EINVAL; |
576 | ||
577 | hmm = hmm_register(vma->vm_mm); | |
578 | if (!hmm) | |
579 | return -ENOMEM; | |
580 | /* Caller must have registered a mirror, via hmm_mirror_register() ! */ | |
581 | if (!hmm->mmu_notifier.ops) | |
582 | return -EINVAL; | |
583 | ||
855ce7d2 JG |
584 | /* FIXME support hugetlb fs */ |
585 | if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { | |
586 | hmm_pfns_special(range); | |
587 | return -EINVAL; | |
588 | } | |
589 | ||
86586a41 JG |
590 | if (!(vma->vm_flags & VM_READ)) { |
591 | /* | |
592 | * If vma do not allow read access, then assume that it does | |
593 | * not allow write access, either. Architecture that allow | |
594 | * write without read access are not supported by HMM, because | |
595 | * operations such has atomic access would not work. | |
596 | */ | |
597 | hmm_pfns_clear(range->pfns, range->start, range->end); | |
598 | return -EPERM; | |
599 | } | |
600 | ||
da4c3c73 | 601 | /* Initialize range to track CPU page table update */ |
da4c3c73 JG |
602 | spin_lock(&hmm->lock); |
603 | range->valid = true; | |
604 | list_add_rcu(&range->list, &hmm->ranges); | |
605 | spin_unlock(&hmm->lock); | |
606 | ||
74eee180 JG |
607 | hmm_vma_walk.fault = false; |
608 | hmm_vma_walk.range = range; | |
609 | mm_walk.private = &hmm_vma_walk; | |
610 | ||
da4c3c73 JG |
611 | mm_walk.vma = vma; |
612 | mm_walk.mm = vma->vm_mm; | |
da4c3c73 JG |
613 | mm_walk.pte_entry = NULL; |
614 | mm_walk.test_walk = NULL; | |
615 | mm_walk.hugetlb_entry = NULL; | |
616 | mm_walk.pmd_entry = hmm_vma_walk_pmd; | |
617 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
618 | ||
08232a45 | 619 | walk_page_range(range->start, range->end, &mm_walk); |
da4c3c73 JG |
620 | return 0; |
621 | } | |
622 | EXPORT_SYMBOL(hmm_vma_get_pfns); | |
623 | ||
624 | /* | |
625 | * hmm_vma_range_done() - stop tracking change to CPU page table over a range | |
da4c3c73 JG |
626 | * @range: range being tracked |
627 | * Returns: false if range data has been invalidated, true otherwise | |
628 | * | |
629 | * Range struct is used to track updates to the CPU page table after a call to | |
630 | * either hmm_vma_get_pfns() or hmm_vma_fault(). Once the device driver is done | |
631 | * using the data, or wants to lock updates to the data it got from those | |
632 | * functions, it must call the hmm_vma_range_done() function, which will then | |
633 | * stop tracking CPU page table updates. | |
634 | * | |
635 | * Note that device driver must still implement general CPU page table update | |
636 | * tracking either by using hmm_mirror (see hmm_mirror_register()) or by using | |
637 | * the mmu_notifier API directly. | |
638 | * | |
639 | * CPU page table update tracking done through hmm_range is only temporary and | |
640 | * to be used while trying to duplicate CPU page table contents for a range of | |
641 | * virtual addresses. | |
642 | * | |
643 | * There are two ways to use this : | |
644 | * again: | |
08232a45 | 645 | * hmm_vma_get_pfns(range); or hmm_vma_fault(...); |
da4c3c73 JG |
646 | * trans = device_build_page_table_update_transaction(pfns); |
647 | * device_page_table_lock(); | |
08232a45 | 648 | * if (!hmm_vma_range_done(range)) { |
da4c3c73 JG |
649 | * device_page_table_unlock(); |
650 | * goto again; | |
651 | * } | |
652 | * device_commit_transaction(trans); | |
653 | * device_page_table_unlock(); | |
654 | * | |
655 | * Or: | |
08232a45 | 656 | * hmm_vma_get_pfns(range); or hmm_vma_fault(...); |
da4c3c73 | 657 | * device_page_table_lock(); |
08232a45 JG |
658 | * hmm_vma_range_done(range); |
659 | * device_update_page_table(range->pfns); | |
da4c3c73 JG |
660 | * device_page_table_unlock(); |
661 | */ | |
08232a45 | 662 | bool hmm_vma_range_done(struct hmm_range *range) |
da4c3c73 JG |
663 | { |
664 | unsigned long npages = (range->end - range->start) >> PAGE_SHIFT; | |
665 | struct hmm *hmm; | |
666 | ||
667 | if (range->end <= range->start) { | |
668 | BUG(); | |
669 | return false; | |
670 | } | |
671 | ||
08232a45 | 672 | hmm = hmm_register(range->vma->vm_mm); |
da4c3c73 JG |
673 | if (!hmm) { |
674 | memset(range->pfns, 0, sizeof(*range->pfns) * npages); | |
675 | return false; | |
676 | } | |
677 | ||
678 | spin_lock(&hmm->lock); | |
679 | list_del_rcu(&range->list); | |
680 | spin_unlock(&hmm->lock); | |
681 | ||
682 | return range->valid; | |
683 | } | |
684 | EXPORT_SYMBOL(hmm_vma_range_done); | |
74eee180 JG |
685 | |
686 | /* | |
687 | * hmm_vma_fault() - try to fault some address in a virtual address range | |
08232a45 | 688 | * @range: range being faulted |
74eee180 JG |
689 | * @write: is it a write fault |
690 | * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) | |
691 | * Returns: 0 success, error otherwise (-EAGAIN means mmap_sem have been drop) | |
692 | * | |
693 | * This is similar to a regular CPU page fault except that it will not trigger | |
694 | * any memory migration if the memory being faulted is not accessible by CPUs. | |
695 | * | |
ff05c0c6 JG |
696 | * On error, for one virtual address in the range, the function will mark the |
697 | * corresponding HMM pfn entry with an error flag. | |
74eee180 JG |
698 | * |
699 | * Expected use pattern: | |
700 | * retry: | |
701 | * down_read(&mm->mmap_sem); | |
702 | * // Find vma and address device wants to fault, initialize hmm_pfn_t | |
703 | * // array accordingly | |
08232a45 | 704 | * ret = hmm_vma_fault(range, write, block); |
74eee180 JG |
705 | * switch (ret) { |
706 | * case -EAGAIN: | |
08232a45 | 707 | * hmm_vma_range_done(range); |
74eee180 JG |
708 | * // You might want to rate limit or yield to play nicely, you may |
709 | * // also commit any valid pfn in the array assuming that you are | |
710 | * // getting true from hmm_vma_range_monitor_end() | |
711 | * goto retry; | |
712 | * case 0: | |
713 | * break; | |
86586a41 JG |
714 | * case -ENOMEM: |
715 | * case -EINVAL: | |
716 | * case -EPERM: | |
74eee180 JG |
717 | * default: |
718 | * // Handle error ! | |
719 | * up_read(&mm->mmap_sem) | |
720 | * return; | |
721 | * } | |
722 | * // Take device driver lock that serialize device page table update | |
723 | * driver_lock_device_page_table_update(); | |
08232a45 | 724 | * hmm_vma_range_done(range); |
74eee180 JG |
725 | * // Commit pfns we got from hmm_vma_fault() |
726 | * driver_unlock_device_page_table_update(); | |
727 | * up_read(&mm->mmap_sem) | |
728 | * | |
729 | * YOU MUST CALL hmm_vma_range_done() AFTER THIS FUNCTION RETURN SUCCESS (0) | |
730 | * BEFORE FREEING THE range struct OR YOU WILL HAVE SERIOUS MEMORY CORRUPTION ! | |
731 | * | |
732 | * YOU HAVE BEEN WARNED ! | |
733 | */ | |
08232a45 | 734 | int hmm_vma_fault(struct hmm_range *range, bool write, bool block) |
74eee180 | 735 | { |
08232a45 JG |
736 | struct vm_area_struct *vma = range->vma; |
737 | unsigned long start = range->start; | |
74eee180 JG |
738 | struct hmm_vma_walk hmm_vma_walk; |
739 | struct mm_walk mm_walk; | |
740 | struct hmm *hmm; | |
741 | int ret; | |
742 | ||
743 | /* Sanity check, this really should not happen ! */ | |
08232a45 | 744 | if (range->start < vma->vm_start || range->start >= vma->vm_end) |
74eee180 | 745 | return -EINVAL; |
08232a45 | 746 | if (range->end < vma->vm_start || range->end > vma->vm_end) |
74eee180 JG |
747 | return -EINVAL; |
748 | ||
749 | hmm = hmm_register(vma->vm_mm); | |
750 | if (!hmm) { | |
08232a45 | 751 | hmm_pfns_clear(range->pfns, range->start, range->end); |
74eee180 JG |
752 | return -ENOMEM; |
753 | } | |
754 | /* Caller must have registered a mirror using hmm_mirror_register() */ | |
755 | if (!hmm->mmu_notifier.ops) | |
756 | return -EINVAL; | |
757 | ||
855ce7d2 JG |
758 | /* FIXME support hugetlb fs */ |
759 | if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { | |
760 | hmm_pfns_special(range); | |
761 | return -EINVAL; | |
762 | } | |
763 | ||
86586a41 JG |
764 | if (!(vma->vm_flags & VM_READ)) { |
765 | /* | |
766 | * If vma do not allow read access, then assume that it does | |
767 | * not allow write access, either. Architecture that allow | |
768 | * write without read access are not supported by HMM, because | |
769 | * operations such has atomic access would not work. | |
770 | */ | |
771 | hmm_pfns_clear(range->pfns, range->start, range->end); | |
772 | return -EPERM; | |
773 | } | |
74eee180 | 774 | |
86586a41 JG |
775 | /* Initialize range to track CPU page table update */ |
776 | spin_lock(&hmm->lock); | |
777 | range->valid = true; | |
778 | list_add_rcu(&range->list, &hmm->ranges); | |
779 | spin_unlock(&hmm->lock); | |
780 | ||
74eee180 JG |
781 | hmm_vma_walk.fault = true; |
782 | hmm_vma_walk.write = write; | |
783 | hmm_vma_walk.block = block; | |
784 | hmm_vma_walk.range = range; | |
785 | mm_walk.private = &hmm_vma_walk; | |
786 | hmm_vma_walk.last = range->start; | |
787 | ||
788 | mm_walk.vma = vma; | |
789 | mm_walk.mm = vma->vm_mm; | |
790 | mm_walk.pte_entry = NULL; | |
791 | mm_walk.test_walk = NULL; | |
792 | mm_walk.hugetlb_entry = NULL; | |
793 | mm_walk.pmd_entry = hmm_vma_walk_pmd; | |
794 | mm_walk.pte_hole = hmm_vma_walk_hole; | |
795 | ||
796 | do { | |
08232a45 | 797 | ret = walk_page_range(start, range->end, &mm_walk); |
74eee180 JG |
798 | start = hmm_vma_walk.last; |
799 | } while (ret == -EAGAIN); | |
800 | ||
801 | if (ret) { | |
802 | unsigned long i; | |
803 | ||
804 | i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; | |
08232a45 JG |
805 | hmm_pfns_clear(&range->pfns[i], hmm_vma_walk.last, range->end); |
806 | hmm_vma_range_done(range); | |
74eee180 JG |
807 | } |
808 | return ret; | |
809 | } | |
810 | EXPORT_SYMBOL(hmm_vma_fault); | |
c0b12405 | 811 | #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ |
4ef589dc JG |
812 | |
813 | ||
df6ad698 | 814 | #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) |
4ef589dc JG |
815 | struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma, |
816 | unsigned long addr) | |
817 | { | |
818 | struct page *page; | |
819 | ||
820 | page = alloc_page_vma(GFP_HIGHUSER, vma, addr); | |
821 | if (!page) | |
822 | return NULL; | |
823 | lock_page(page); | |
824 | return page; | |
825 | } | |
826 | EXPORT_SYMBOL(hmm_vma_alloc_locked_page); | |
827 | ||
828 | ||
829 | static void hmm_devmem_ref_release(struct percpu_ref *ref) | |
830 | { | |
831 | struct hmm_devmem *devmem; | |
832 | ||
833 | devmem = container_of(ref, struct hmm_devmem, ref); | |
834 | complete(&devmem->completion); | |
835 | } | |
836 | ||
837 | static void hmm_devmem_ref_exit(void *data) | |
838 | { | |
839 | struct percpu_ref *ref = data; | |
840 | struct hmm_devmem *devmem; | |
841 | ||
842 | devmem = container_of(ref, struct hmm_devmem, ref); | |
843 | percpu_ref_exit(ref); | |
844 | devm_remove_action(devmem->device, &hmm_devmem_ref_exit, data); | |
845 | } | |
846 | ||
847 | static void hmm_devmem_ref_kill(void *data) | |
848 | { | |
849 | struct percpu_ref *ref = data; | |
850 | struct hmm_devmem *devmem; | |
851 | ||
852 | devmem = container_of(ref, struct hmm_devmem, ref); | |
853 | percpu_ref_kill(ref); | |
854 | wait_for_completion(&devmem->completion); | |
855 | devm_remove_action(devmem->device, &hmm_devmem_ref_kill, data); | |
856 | } | |
857 | ||
858 | static int hmm_devmem_fault(struct vm_area_struct *vma, | |
859 | unsigned long addr, | |
860 | const struct page *page, | |
861 | unsigned int flags, | |
862 | pmd_t *pmdp) | |
863 | { | |
864 | struct hmm_devmem *devmem = page->pgmap->data; | |
865 | ||
866 | return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); | |
867 | } | |
868 | ||
869 | static void hmm_devmem_free(struct page *page, void *data) | |
870 | { | |
871 | struct hmm_devmem *devmem = data; | |
872 | ||
873 | devmem->ops->free(devmem, page); | |
874 | } | |
875 | ||
876 | static DEFINE_MUTEX(hmm_devmem_lock); | |
877 | static RADIX_TREE(hmm_devmem_radix, GFP_KERNEL); | |
878 | ||
879 | static void hmm_devmem_radix_release(struct resource *resource) | |
880 | { | |
fec11bc0 | 881 | resource_size_t key, align_start, align_size; |
4ef589dc JG |
882 | |
883 | align_start = resource->start & ~(PA_SECTION_SIZE - 1); | |
884 | align_size = ALIGN(resource_size(resource), PA_SECTION_SIZE); | |
4ef589dc JG |
885 | |
886 | mutex_lock(&hmm_devmem_lock); | |
887 | for (key = resource->start; | |
888 | key <= resource->end; | |
889 | key += PA_SECTION_SIZE) | |
890 | radix_tree_delete(&hmm_devmem_radix, key >> PA_SECTION_SHIFT); | |
891 | mutex_unlock(&hmm_devmem_lock); | |
892 | } | |
893 | ||
894 | static void hmm_devmem_release(struct device *dev, void *data) | |
895 | { | |
896 | struct hmm_devmem *devmem = data; | |
897 | struct resource *resource = devmem->resource; | |
898 | unsigned long start_pfn, npages; | |
899 | struct zone *zone; | |
900 | struct page *page; | |
901 | ||
902 | if (percpu_ref_tryget_live(&devmem->ref)) { | |
903 | dev_WARN(dev, "%s: page mapping is still live!\n", __func__); | |
904 | percpu_ref_put(&devmem->ref); | |
905 | } | |
906 | ||
907 | /* pages are dead and unused, undo the arch mapping */ | |
908 | start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT; | |
909 | npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT; | |
910 | ||
911 | page = pfn_to_page(start_pfn); | |
912 | zone = page_zone(page); | |
913 | ||
914 | mem_hotplug_begin(); | |
d3df0a42 | 915 | if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) |
da024512 | 916 | __remove_pages(zone, start_pfn, npages, NULL); |
d3df0a42 JG |
917 | else |
918 | arch_remove_memory(start_pfn << PAGE_SHIFT, | |
da024512 | 919 | npages << PAGE_SHIFT, NULL); |
4ef589dc JG |
920 | mem_hotplug_done(); |
921 | ||
922 | hmm_devmem_radix_release(resource); | |
923 | } | |
924 | ||
925 | static struct hmm_devmem *hmm_devmem_find(resource_size_t phys) | |
926 | { | |
927 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
928 | ||
929 | return radix_tree_lookup(&hmm_devmem_radix, phys >> PA_SECTION_SHIFT); | |
930 | } | |
931 | ||
932 | static int hmm_devmem_pages_create(struct hmm_devmem *devmem) | |
933 | { | |
934 | resource_size_t key, align_start, align_size, align_end; | |
935 | struct device *device = devmem->device; | |
936 | int ret, nid, is_ram; | |
937 | unsigned long pfn; | |
938 | ||
939 | align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1); | |
940 | align_size = ALIGN(devmem->resource->start + | |
941 | resource_size(devmem->resource), | |
942 | PA_SECTION_SIZE) - align_start; | |
943 | ||
944 | is_ram = region_intersects(align_start, align_size, | |
945 | IORESOURCE_SYSTEM_RAM, | |
946 | IORES_DESC_NONE); | |
947 | if (is_ram == REGION_MIXED) { | |
948 | WARN_ONCE(1, "%s attempted on mixed region %pr\n", | |
949 | __func__, devmem->resource); | |
950 | return -ENXIO; | |
951 | } | |
952 | if (is_ram == REGION_INTERSECTS) | |
953 | return -ENXIO; | |
954 | ||
d3df0a42 JG |
955 | if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY) |
956 | devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; | |
957 | else | |
958 | devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; | |
959 | ||
e7744aa2 | 960 | devmem->pagemap.res = *devmem->resource; |
4ef589dc JG |
961 | devmem->pagemap.page_fault = hmm_devmem_fault; |
962 | devmem->pagemap.page_free = hmm_devmem_free; | |
963 | devmem->pagemap.dev = devmem->device; | |
964 | devmem->pagemap.ref = &devmem->ref; | |
965 | devmem->pagemap.data = devmem; | |
966 | ||
967 | mutex_lock(&hmm_devmem_lock); | |
968 | align_end = align_start + align_size - 1; | |
969 | for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) { | |
970 | struct hmm_devmem *dup; | |
971 | ||
972 | rcu_read_lock(); | |
973 | dup = hmm_devmem_find(key); | |
974 | rcu_read_unlock(); | |
975 | if (dup) { | |
976 | dev_err(device, "%s: collides with mapping for %s\n", | |
977 | __func__, dev_name(dup->device)); | |
978 | mutex_unlock(&hmm_devmem_lock); | |
979 | ret = -EBUSY; | |
980 | goto error; | |
981 | } | |
982 | ret = radix_tree_insert(&hmm_devmem_radix, | |
983 | key >> PA_SECTION_SHIFT, | |
984 | devmem); | |
985 | if (ret) { | |
986 | dev_err(device, "%s: failed: %d\n", __func__, ret); | |
987 | mutex_unlock(&hmm_devmem_lock); | |
988 | goto error_radix; | |
989 | } | |
990 | } | |
991 | mutex_unlock(&hmm_devmem_lock); | |
992 | ||
993 | nid = dev_to_node(device); | |
994 | if (nid < 0) | |
995 | nid = numa_mem_id(); | |
996 | ||
997 | mem_hotplug_begin(); | |
998 | /* | |
999 | * For device private memory we call add_pages() as we only need to | |
1000 | * allocate and initialize struct page for the device memory. More- | |
1001 | * over the device memory is un-accessible thus we do not want to | |
1002 | * create a linear mapping for the memory like arch_add_memory() | |
1003 | * would do. | |
d3df0a42 JG |
1004 | * |
1005 | * For device public memory, which is accesible by the CPU, we do | |
1006 | * want the linear mapping and thus use arch_add_memory(). | |
4ef589dc | 1007 | */ |
d3df0a42 | 1008 | if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC) |
24e6d5a5 CH |
1009 | ret = arch_add_memory(nid, align_start, align_size, NULL, |
1010 | false); | |
d3df0a42 JG |
1011 | else |
1012 | ret = add_pages(nid, align_start >> PAGE_SHIFT, | |
24e6d5a5 | 1013 | align_size >> PAGE_SHIFT, NULL, false); |
4ef589dc JG |
1014 | if (ret) { |
1015 | mem_hotplug_done(); | |
1016 | goto error_add_memory; | |
1017 | } | |
1018 | move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], | |
1019 | align_start >> PAGE_SHIFT, | |
a99583e7 | 1020 | align_size >> PAGE_SHIFT, NULL); |
4ef589dc JG |
1021 | mem_hotplug_done(); |
1022 | ||
1023 | for (pfn = devmem->pfn_first; pfn < devmem->pfn_last; pfn++) { | |
1024 | struct page *page = pfn_to_page(pfn); | |
1025 | ||
1026 | page->pgmap = &devmem->pagemap; | |
1027 | } | |
1028 | return 0; | |
1029 | ||
1030 | error_add_memory: | |
1031 | untrack_pfn(NULL, PHYS_PFN(align_start), align_size); | |
1032 | error_radix: | |
1033 | hmm_devmem_radix_release(devmem->resource); | |
1034 | error: | |
1035 | return ret; | |
1036 | } | |
1037 | ||
1038 | static int hmm_devmem_match(struct device *dev, void *data, void *match_data) | |
1039 | { | |
1040 | struct hmm_devmem *devmem = data; | |
1041 | ||
1042 | return devmem->resource == match_data; | |
1043 | } | |
1044 | ||
1045 | static void hmm_devmem_pages_remove(struct hmm_devmem *devmem) | |
1046 | { | |
1047 | devres_release(devmem->device, &hmm_devmem_release, | |
1048 | &hmm_devmem_match, devmem->resource); | |
1049 | } | |
1050 | ||
1051 | /* | |
1052 | * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory | |
1053 | * | |
1054 | * @ops: memory event device driver callback (see struct hmm_devmem_ops) | |
1055 | * @device: device struct to bind the resource too | |
1056 | * @size: size in bytes of the device memory to add | |
1057 | * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise | |
1058 | * | |
1059 | * This function first finds an empty range of physical address big enough to | |
1060 | * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which | |
1061 | * in turn allocates struct pages. It does not do anything beyond that; all | |
1062 | * events affecting the memory will go through the various callbacks provided | |
1063 | * by hmm_devmem_ops struct. | |
1064 | * | |
1065 | * Device driver should call this function during device initialization and | |
1066 | * is then responsible of memory management. HMM only provides helpers. | |
1067 | */ | |
1068 | struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, | |
1069 | struct device *device, | |
1070 | unsigned long size) | |
1071 | { | |
1072 | struct hmm_devmem *devmem; | |
1073 | resource_size_t addr; | |
1074 | int ret; | |
1075 | ||
1076 | static_branch_enable(&device_private_key); | |
1077 | ||
1078 | devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), | |
1079 | GFP_KERNEL, dev_to_node(device)); | |
1080 | if (!devmem) | |
1081 | return ERR_PTR(-ENOMEM); | |
1082 | ||
1083 | init_completion(&devmem->completion); | |
1084 | devmem->pfn_first = -1UL; | |
1085 | devmem->pfn_last = -1UL; | |
1086 | devmem->resource = NULL; | |
1087 | devmem->device = device; | |
1088 | devmem->ops = ops; | |
1089 | ||
1090 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1091 | 0, GFP_KERNEL); | |
1092 | if (ret) | |
1093 | goto error_percpu_ref; | |
1094 | ||
1095 | ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); | |
1096 | if (ret) | |
1097 | goto error_devm_add_action; | |
1098 | ||
1099 | size = ALIGN(size, PA_SECTION_SIZE); | |
1100 | addr = min((unsigned long)iomem_resource.end, | |
1101 | (1UL << MAX_PHYSMEM_BITS) - 1); | |
1102 | addr = addr - size + 1UL; | |
1103 | ||
1104 | /* | |
1105 | * FIXME add a new helper to quickly walk resource tree and find free | |
1106 | * range | |
1107 | * | |
1108 | * FIXME what about ioport_resource resource ? | |
1109 | */ | |
1110 | for (; addr > size && addr >= iomem_resource.start; addr -= size) { | |
1111 | ret = region_intersects(addr, size, 0, IORES_DESC_NONE); | |
1112 | if (ret != REGION_DISJOINT) | |
1113 | continue; | |
1114 | ||
1115 | devmem->resource = devm_request_mem_region(device, addr, size, | |
1116 | dev_name(device)); | |
1117 | if (!devmem->resource) { | |
1118 | ret = -ENOMEM; | |
1119 | goto error_no_resource; | |
1120 | } | |
1121 | break; | |
1122 | } | |
1123 | if (!devmem->resource) { | |
1124 | ret = -ERANGE; | |
1125 | goto error_no_resource; | |
1126 | } | |
1127 | ||
1128 | devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; | |
1129 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1130 | devmem->pfn_last = devmem->pfn_first + | |
1131 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
1132 | ||
1133 | ret = hmm_devmem_pages_create(devmem); | |
1134 | if (ret) | |
1135 | goto error_pages; | |
1136 | ||
1137 | devres_add(device, devmem); | |
1138 | ||
1139 | ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); | |
1140 | if (ret) { | |
1141 | hmm_devmem_remove(devmem); | |
1142 | return ERR_PTR(ret); | |
1143 | } | |
1144 | ||
1145 | return devmem; | |
1146 | ||
1147 | error_pages: | |
1148 | devm_release_mem_region(device, devmem->resource->start, | |
1149 | resource_size(devmem->resource)); | |
1150 | error_no_resource: | |
1151 | error_devm_add_action: | |
1152 | hmm_devmem_ref_kill(&devmem->ref); | |
1153 | hmm_devmem_ref_exit(&devmem->ref); | |
1154 | error_percpu_ref: | |
1155 | devres_free(devmem); | |
1156 | return ERR_PTR(ret); | |
1157 | } | |
1158 | EXPORT_SYMBOL(hmm_devmem_add); | |
1159 | ||
d3df0a42 JG |
1160 | struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, |
1161 | struct device *device, | |
1162 | struct resource *res) | |
1163 | { | |
1164 | struct hmm_devmem *devmem; | |
1165 | int ret; | |
1166 | ||
1167 | if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) | |
1168 | return ERR_PTR(-EINVAL); | |
1169 | ||
1170 | static_branch_enable(&device_private_key); | |
1171 | ||
1172 | devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), | |
1173 | GFP_KERNEL, dev_to_node(device)); | |
1174 | if (!devmem) | |
1175 | return ERR_PTR(-ENOMEM); | |
1176 | ||
1177 | init_completion(&devmem->completion); | |
1178 | devmem->pfn_first = -1UL; | |
1179 | devmem->pfn_last = -1UL; | |
1180 | devmem->resource = res; | |
1181 | devmem->device = device; | |
1182 | devmem->ops = ops; | |
1183 | ||
1184 | ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, | |
1185 | 0, GFP_KERNEL); | |
1186 | if (ret) | |
1187 | goto error_percpu_ref; | |
1188 | ||
1189 | ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); | |
1190 | if (ret) | |
1191 | goto error_devm_add_action; | |
1192 | ||
1193 | ||
1194 | devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; | |
1195 | devmem->pfn_last = devmem->pfn_first + | |
1196 | (resource_size(devmem->resource) >> PAGE_SHIFT); | |
1197 | ||
1198 | ret = hmm_devmem_pages_create(devmem); | |
1199 | if (ret) | |
1200 | goto error_devm_add_action; | |
1201 | ||
1202 | devres_add(device, devmem); | |
1203 | ||
1204 | ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); | |
1205 | if (ret) { | |
1206 | hmm_devmem_remove(devmem); | |
1207 | return ERR_PTR(ret); | |
1208 | } | |
1209 | ||
1210 | return devmem; | |
1211 | ||
1212 | error_devm_add_action: | |
1213 | hmm_devmem_ref_kill(&devmem->ref); | |
1214 | hmm_devmem_ref_exit(&devmem->ref); | |
1215 | error_percpu_ref: | |
1216 | devres_free(devmem); | |
1217 | return ERR_PTR(ret); | |
1218 | } | |
1219 | EXPORT_SYMBOL(hmm_devmem_add_resource); | |
1220 | ||
4ef589dc JG |
1221 | /* |
1222 | * hmm_devmem_remove() - remove device memory (kill and free ZONE_DEVICE) | |
1223 | * | |
1224 | * @devmem: hmm_devmem struct use to track and manage the ZONE_DEVICE memory | |
1225 | * | |
1226 | * This will hot-unplug memory that was hotplugged by hmm_devmem_add on behalf | |
1227 | * of the device driver. It will free struct page and remove the resource that | |
1228 | * reserved the physical address range for this device memory. | |
1229 | */ | |
1230 | void hmm_devmem_remove(struct hmm_devmem *devmem) | |
1231 | { | |
1232 | resource_size_t start, size; | |
1233 | struct device *device; | |
d3df0a42 | 1234 | bool cdm = false; |
4ef589dc JG |
1235 | |
1236 | if (!devmem) | |
1237 | return; | |
1238 | ||
1239 | device = devmem->device; | |
1240 | start = devmem->resource->start; | |
1241 | size = resource_size(devmem->resource); | |
1242 | ||
d3df0a42 | 1243 | cdm = devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY; |
4ef589dc JG |
1244 | hmm_devmem_ref_kill(&devmem->ref); |
1245 | hmm_devmem_ref_exit(&devmem->ref); | |
1246 | hmm_devmem_pages_remove(devmem); | |
1247 | ||
d3df0a42 JG |
1248 | if (!cdm) |
1249 | devm_release_mem_region(device, start, size); | |
4ef589dc JG |
1250 | } |
1251 | EXPORT_SYMBOL(hmm_devmem_remove); | |
858b54da JG |
1252 | |
1253 | /* | |
1254 | * A device driver that wants to handle multiple devices memory through a | |
1255 | * single fake device can use hmm_device to do so. This is purely a helper | |
1256 | * and it is not needed to make use of any HMM functionality. | |
1257 | */ | |
1258 | #define HMM_DEVICE_MAX 256 | |
1259 | ||
1260 | static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); | |
1261 | static DEFINE_SPINLOCK(hmm_device_lock); | |
1262 | static struct class *hmm_device_class; | |
1263 | static dev_t hmm_device_devt; | |
1264 | ||
1265 | static void hmm_device_release(struct device *device) | |
1266 | { | |
1267 | struct hmm_device *hmm_device; | |
1268 | ||
1269 | hmm_device = container_of(device, struct hmm_device, device); | |
1270 | spin_lock(&hmm_device_lock); | |
1271 | clear_bit(hmm_device->minor, hmm_device_mask); | |
1272 | spin_unlock(&hmm_device_lock); | |
1273 | ||
1274 | kfree(hmm_device); | |
1275 | } | |
1276 | ||
1277 | struct hmm_device *hmm_device_new(void *drvdata) | |
1278 | { | |
1279 | struct hmm_device *hmm_device; | |
1280 | ||
1281 | hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); | |
1282 | if (!hmm_device) | |
1283 | return ERR_PTR(-ENOMEM); | |
1284 | ||
1285 | spin_lock(&hmm_device_lock); | |
1286 | hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); | |
1287 | if (hmm_device->minor >= HMM_DEVICE_MAX) { | |
1288 | spin_unlock(&hmm_device_lock); | |
1289 | kfree(hmm_device); | |
1290 | return ERR_PTR(-EBUSY); | |
1291 | } | |
1292 | set_bit(hmm_device->minor, hmm_device_mask); | |
1293 | spin_unlock(&hmm_device_lock); | |
1294 | ||
1295 | dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); | |
1296 | hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), | |
1297 | hmm_device->minor); | |
1298 | hmm_device->device.release = hmm_device_release; | |
1299 | dev_set_drvdata(&hmm_device->device, drvdata); | |
1300 | hmm_device->device.class = hmm_device_class; | |
1301 | device_initialize(&hmm_device->device); | |
1302 | ||
1303 | return hmm_device; | |
1304 | } | |
1305 | EXPORT_SYMBOL(hmm_device_new); | |
1306 | ||
1307 | void hmm_device_put(struct hmm_device *hmm_device) | |
1308 | { | |
1309 | put_device(&hmm_device->device); | |
1310 | } | |
1311 | EXPORT_SYMBOL(hmm_device_put); | |
1312 | ||
1313 | static int __init hmm_init(void) | |
1314 | { | |
1315 | int ret; | |
1316 | ||
1317 | ret = alloc_chrdev_region(&hmm_device_devt, 0, | |
1318 | HMM_DEVICE_MAX, | |
1319 | "hmm_device"); | |
1320 | if (ret) | |
1321 | return ret; | |
1322 | ||
1323 | hmm_device_class = class_create(THIS_MODULE, "hmm_device"); | |
1324 | if (IS_ERR(hmm_device_class)) { | |
1325 | unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); | |
1326 | return PTR_ERR(hmm_device_class); | |
1327 | } | |
1328 | return 0; | |
1329 | } | |
1330 | ||
1331 | device_initcall(hmm_init); | |
df6ad698 | 1332 | #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ |