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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * linux/mm/madvise.c | |
4 | * | |
5 | * Copyright (C) 1999 Linus Torvalds | |
6 | * Copyright (C) 2002 Christoph Hellwig | |
7 | */ | |
8 | ||
9 | #include <linux/mman.h> | |
10 | #include <linux/pagemap.h> | |
11 | #include <linux/syscalls.h> | |
12 | #include <linux/mempolicy.h> | |
13 | #include <linux/page-isolation.h> | |
14 | #include <linux/page_idle.h> | |
15 | #include <linux/userfaultfd_k.h> | |
16 | #include <linux/hugetlb.h> | |
17 | #include <linux/falloc.h> | |
18 | #include <linux/fadvise.h> | |
19 | #include <linux/sched.h> | |
20 | #include <linux/sched/mm.h> | |
21 | #include <linux/uio.h> | |
22 | #include <linux/ksm.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/file.h> | |
25 | #include <linux/blkdev.h> | |
26 | #include <linux/backing-dev.h> | |
27 | #include <linux/pagewalk.h> | |
28 | #include <linux/swap.h> | |
29 | #include <linux/swapops.h> | |
30 | #include <linux/shmem_fs.h> | |
31 | #include <linux/mmu_notifier.h> | |
32 | ||
33 | #include <asm/tlb.h> | |
34 | ||
35 | #include "internal.h" | |
36 | ||
37 | struct madvise_walk_private { | |
38 | struct mmu_gather *tlb; | |
39 | bool pageout; | |
40 | }; | |
41 | ||
42 | /* | |
43 | * Any behaviour which results in changes to the vma->vm_flags needs to | |
44 | * take mmap_lock for writing. Others, which simply traverse vmas, need | |
45 | * to only take it for reading. | |
46 | */ | |
47 | static int madvise_need_mmap_write(int behavior) | |
48 | { | |
49 | switch (behavior) { | |
50 | case MADV_REMOVE: | |
51 | case MADV_WILLNEED: | |
52 | case MADV_DONTNEED: | |
53 | case MADV_COLD: | |
54 | case MADV_PAGEOUT: | |
55 | case MADV_FREE: | |
56 | case MADV_POPULATE_READ: | |
57 | case MADV_POPULATE_WRITE: | |
58 | return 0; | |
59 | default: | |
60 | /* be safe, default to 1. list exceptions explicitly */ | |
61 | return 1; | |
62 | } | |
63 | } | |
64 | ||
65 | /* | |
66 | * We can potentially split a vm area into separate | |
67 | * areas, each area with its own behavior. | |
68 | */ | |
69 | static long madvise_behavior(struct vm_area_struct *vma, | |
70 | struct vm_area_struct **prev, | |
71 | unsigned long start, unsigned long end, int behavior) | |
72 | { | |
73 | struct mm_struct *mm = vma->vm_mm; | |
74 | int error = 0; | |
75 | pgoff_t pgoff; | |
76 | unsigned long new_flags = vma->vm_flags; | |
77 | ||
78 | switch (behavior) { | |
79 | case MADV_NORMAL: | |
80 | new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ; | |
81 | break; | |
82 | case MADV_SEQUENTIAL: | |
83 | new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ; | |
84 | break; | |
85 | case MADV_RANDOM: | |
86 | new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ; | |
87 | break; | |
88 | case MADV_DONTFORK: | |
89 | new_flags |= VM_DONTCOPY; | |
90 | break; | |
91 | case MADV_DOFORK: | |
92 | if (vma->vm_flags & VM_IO) { | |
93 | error = -EINVAL; | |
94 | goto out; | |
95 | } | |
96 | new_flags &= ~VM_DONTCOPY; | |
97 | break; | |
98 | case MADV_WIPEONFORK: | |
99 | /* MADV_WIPEONFORK is only supported on anonymous memory. */ | |
100 | if (vma->vm_file || vma->vm_flags & VM_SHARED) { | |
101 | error = -EINVAL; | |
102 | goto out; | |
103 | } | |
104 | new_flags |= VM_WIPEONFORK; | |
105 | break; | |
106 | case MADV_KEEPONFORK: | |
107 | new_flags &= ~VM_WIPEONFORK; | |
108 | break; | |
109 | case MADV_DONTDUMP: | |
110 | new_flags |= VM_DONTDUMP; | |
111 | break; | |
112 | case MADV_DODUMP: | |
113 | if (!is_vm_hugetlb_page(vma) && new_flags & VM_SPECIAL) { | |
114 | error = -EINVAL; | |
115 | goto out; | |
116 | } | |
117 | new_flags &= ~VM_DONTDUMP; | |
118 | break; | |
119 | case MADV_MERGEABLE: | |
120 | case MADV_UNMERGEABLE: | |
121 | error = ksm_madvise(vma, start, end, behavior, &new_flags); | |
122 | if (error) | |
123 | goto out_convert_errno; | |
124 | break; | |
125 | case MADV_HUGEPAGE: | |
126 | case MADV_NOHUGEPAGE: | |
127 | error = hugepage_madvise(vma, &new_flags, behavior); | |
128 | if (error) | |
129 | goto out_convert_errno; | |
130 | break; | |
131 | } | |
132 | ||
133 | if (new_flags == vma->vm_flags) { | |
134 | *prev = vma; | |
135 | goto out; | |
136 | } | |
137 | ||
138 | pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); | |
139 | *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma, | |
140 | vma->vm_file, pgoff, vma_policy(vma), | |
141 | vma->vm_userfaultfd_ctx); | |
142 | if (*prev) { | |
143 | vma = *prev; | |
144 | goto success; | |
145 | } | |
146 | ||
147 | *prev = vma; | |
148 | ||
149 | if (start != vma->vm_start) { | |
150 | if (unlikely(mm->map_count >= sysctl_max_map_count)) { | |
151 | error = -ENOMEM; | |
152 | goto out; | |
153 | } | |
154 | error = __split_vma(mm, vma, start, 1); | |
155 | if (error) | |
156 | goto out_convert_errno; | |
157 | } | |
158 | ||
159 | if (end != vma->vm_end) { | |
160 | if (unlikely(mm->map_count >= sysctl_max_map_count)) { | |
161 | error = -ENOMEM; | |
162 | goto out; | |
163 | } | |
164 | error = __split_vma(mm, vma, end, 0); | |
165 | if (error) | |
166 | goto out_convert_errno; | |
167 | } | |
168 | ||
169 | success: | |
170 | /* | |
171 | * vm_flags is protected by the mmap_lock held in write mode. | |
172 | */ | |
173 | vma->vm_flags = new_flags; | |
174 | ||
175 | out_convert_errno: | |
176 | /* | |
177 | * madvise() returns EAGAIN if kernel resources, such as | |
178 | * slab, are temporarily unavailable. | |
179 | */ | |
180 | if (error == -ENOMEM) | |
181 | error = -EAGAIN; | |
182 | out: | |
183 | return error; | |
184 | } | |
185 | ||
186 | #ifdef CONFIG_SWAP | |
187 | static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start, | |
188 | unsigned long end, struct mm_walk *walk) | |
189 | { | |
190 | pte_t *orig_pte; | |
191 | struct vm_area_struct *vma = walk->private; | |
192 | unsigned long index; | |
193 | ||
194 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) | |
195 | return 0; | |
196 | ||
197 | for (index = start; index != end; index += PAGE_SIZE) { | |
198 | pte_t pte; | |
199 | swp_entry_t entry; | |
200 | struct page *page; | |
201 | spinlock_t *ptl; | |
202 | ||
203 | orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); | |
204 | pte = *(orig_pte + ((index - start) / PAGE_SIZE)); | |
205 | pte_unmap_unlock(orig_pte, ptl); | |
206 | ||
207 | if (pte_present(pte) || pte_none(pte)) | |
208 | continue; | |
209 | entry = pte_to_swp_entry(pte); | |
210 | if (unlikely(non_swap_entry(entry))) | |
211 | continue; | |
212 | ||
213 | page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE, | |
214 | vma, index, false); | |
215 | if (page) | |
216 | put_page(page); | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | static const struct mm_walk_ops swapin_walk_ops = { | |
223 | .pmd_entry = swapin_walk_pmd_entry, | |
224 | }; | |
225 | ||
226 | static void force_shm_swapin_readahead(struct vm_area_struct *vma, | |
227 | unsigned long start, unsigned long end, | |
228 | struct address_space *mapping) | |
229 | { | |
230 | XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start)); | |
231 | pgoff_t end_index = linear_page_index(vma, end + PAGE_SIZE - 1); | |
232 | struct page *page; | |
233 | ||
234 | rcu_read_lock(); | |
235 | xas_for_each(&xas, page, end_index) { | |
236 | swp_entry_t swap; | |
237 | ||
238 | if (!xa_is_value(page)) | |
239 | continue; | |
240 | xas_pause(&xas); | |
241 | rcu_read_unlock(); | |
242 | ||
243 | swap = radix_to_swp_entry(page); | |
244 | page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE, | |
245 | NULL, 0, false); | |
246 | if (page) | |
247 | put_page(page); | |
248 | ||
249 | rcu_read_lock(); | |
250 | } | |
251 | rcu_read_unlock(); | |
252 | ||
253 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
254 | } | |
255 | #endif /* CONFIG_SWAP */ | |
256 | ||
257 | /* | |
258 | * Schedule all required I/O operations. Do not wait for completion. | |
259 | */ | |
260 | static long madvise_willneed(struct vm_area_struct *vma, | |
261 | struct vm_area_struct **prev, | |
262 | unsigned long start, unsigned long end) | |
263 | { | |
264 | struct mm_struct *mm = vma->vm_mm; | |
265 | struct file *file = vma->vm_file; | |
266 | loff_t offset; | |
267 | ||
268 | *prev = vma; | |
269 | #ifdef CONFIG_SWAP | |
270 | if (!file) { | |
271 | walk_page_range(vma->vm_mm, start, end, &swapin_walk_ops, vma); | |
272 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
273 | return 0; | |
274 | } | |
275 | ||
276 | if (shmem_mapping(file->f_mapping)) { | |
277 | force_shm_swapin_readahead(vma, start, end, | |
278 | file->f_mapping); | |
279 | return 0; | |
280 | } | |
281 | #else | |
282 | if (!file) | |
283 | return -EBADF; | |
284 | #endif | |
285 | ||
286 | if (IS_DAX(file_inode(file))) { | |
287 | /* no bad return value, but ignore advice */ | |
288 | return 0; | |
289 | } | |
290 | ||
291 | /* | |
292 | * Filesystem's fadvise may need to take various locks. We need to | |
293 | * explicitly grab a reference because the vma (and hence the | |
294 | * vma's reference to the file) can go away as soon as we drop | |
295 | * mmap_lock. | |
296 | */ | |
297 | *prev = NULL; /* tell sys_madvise we drop mmap_lock */ | |
298 | get_file(file); | |
299 | offset = (loff_t)(start - vma->vm_start) | |
300 | + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); | |
301 | mmap_read_unlock(mm); | |
302 | vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); | |
303 | fput(file); | |
304 | mmap_read_lock(mm); | |
305 | return 0; | |
306 | } | |
307 | ||
308 | static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, | |
309 | unsigned long addr, unsigned long end, | |
310 | struct mm_walk *walk) | |
311 | { | |
312 | struct madvise_walk_private *private = walk->private; | |
313 | struct mmu_gather *tlb = private->tlb; | |
314 | bool pageout = private->pageout; | |
315 | struct mm_struct *mm = tlb->mm; | |
316 | struct vm_area_struct *vma = walk->vma; | |
317 | pte_t *orig_pte, *pte, ptent; | |
318 | spinlock_t *ptl; | |
319 | struct page *page = NULL; | |
320 | LIST_HEAD(page_list); | |
321 | ||
322 | if (fatal_signal_pending(current)) | |
323 | return -EINTR; | |
324 | ||
325 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
326 | if (pmd_trans_huge(*pmd)) { | |
327 | pmd_t orig_pmd; | |
328 | unsigned long next = pmd_addr_end(addr, end); | |
329 | ||
330 | tlb_change_page_size(tlb, HPAGE_PMD_SIZE); | |
331 | ptl = pmd_trans_huge_lock(pmd, vma); | |
332 | if (!ptl) | |
333 | return 0; | |
334 | ||
335 | orig_pmd = *pmd; | |
336 | if (is_huge_zero_pmd(orig_pmd)) | |
337 | goto huge_unlock; | |
338 | ||
339 | if (unlikely(!pmd_present(orig_pmd))) { | |
340 | VM_BUG_ON(thp_migration_supported() && | |
341 | !is_pmd_migration_entry(orig_pmd)); | |
342 | goto huge_unlock; | |
343 | } | |
344 | ||
345 | page = pmd_page(orig_pmd); | |
346 | ||
347 | /* Do not interfere with other mappings of this page */ | |
348 | if (page_mapcount(page) != 1) | |
349 | goto huge_unlock; | |
350 | ||
351 | if (next - addr != HPAGE_PMD_SIZE) { | |
352 | int err; | |
353 | ||
354 | get_page(page); | |
355 | spin_unlock(ptl); | |
356 | lock_page(page); | |
357 | err = split_huge_page(page); | |
358 | unlock_page(page); | |
359 | put_page(page); | |
360 | if (!err) | |
361 | goto regular_page; | |
362 | return 0; | |
363 | } | |
364 | ||
365 | if (pmd_young(orig_pmd)) { | |
366 | pmdp_invalidate(vma, addr, pmd); | |
367 | orig_pmd = pmd_mkold(orig_pmd); | |
368 | ||
369 | set_pmd_at(mm, addr, pmd, orig_pmd); | |
370 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); | |
371 | } | |
372 | ||
373 | ClearPageReferenced(page); | |
374 | test_and_clear_page_young(page); | |
375 | if (pageout) { | |
376 | if (!isolate_lru_page(page)) { | |
377 | if (PageUnevictable(page)) | |
378 | putback_lru_page(page); | |
379 | else | |
380 | list_add(&page->lru, &page_list); | |
381 | } | |
382 | } else | |
383 | deactivate_page(page); | |
384 | huge_unlock: | |
385 | spin_unlock(ptl); | |
386 | if (pageout) | |
387 | reclaim_pages(&page_list); | |
388 | return 0; | |
389 | } | |
390 | ||
391 | regular_page: | |
392 | if (pmd_trans_unstable(pmd)) | |
393 | return 0; | |
394 | #endif | |
395 | tlb_change_page_size(tlb, PAGE_SIZE); | |
396 | orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | |
397 | flush_tlb_batched_pending(mm); | |
398 | arch_enter_lazy_mmu_mode(); | |
399 | for (; addr < end; pte++, addr += PAGE_SIZE) { | |
400 | ptent = *pte; | |
401 | ||
402 | if (pte_none(ptent)) | |
403 | continue; | |
404 | ||
405 | if (!pte_present(ptent)) | |
406 | continue; | |
407 | ||
408 | page = vm_normal_page(vma, addr, ptent); | |
409 | if (!page) | |
410 | continue; | |
411 | ||
412 | /* | |
413 | * Creating a THP page is expensive so split it only if we | |
414 | * are sure it's worth. Split it if we are only owner. | |
415 | */ | |
416 | if (PageTransCompound(page)) { | |
417 | if (page_mapcount(page) != 1) | |
418 | break; | |
419 | get_page(page); | |
420 | if (!trylock_page(page)) { | |
421 | put_page(page); | |
422 | break; | |
423 | } | |
424 | pte_unmap_unlock(orig_pte, ptl); | |
425 | if (split_huge_page(page)) { | |
426 | unlock_page(page); | |
427 | put_page(page); | |
428 | pte_offset_map_lock(mm, pmd, addr, &ptl); | |
429 | break; | |
430 | } | |
431 | unlock_page(page); | |
432 | put_page(page); | |
433 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); | |
434 | pte--; | |
435 | addr -= PAGE_SIZE; | |
436 | continue; | |
437 | } | |
438 | ||
439 | /* Do not interfere with other mappings of this page */ | |
440 | if (page_mapcount(page) != 1) | |
441 | continue; | |
442 | ||
443 | VM_BUG_ON_PAGE(PageTransCompound(page), page); | |
444 | ||
445 | if (pte_young(ptent)) { | |
446 | ptent = ptep_get_and_clear_full(mm, addr, pte, | |
447 | tlb->fullmm); | |
448 | ptent = pte_mkold(ptent); | |
449 | set_pte_at(mm, addr, pte, ptent); | |
450 | tlb_remove_tlb_entry(tlb, pte, addr); | |
451 | } | |
452 | ||
453 | /* | |
454 | * We are deactivating a page for accelerating reclaiming. | |
455 | * VM couldn't reclaim the page unless we clear PG_young. | |
456 | * As a side effect, it makes confuse idle-page tracking | |
457 | * because they will miss recent referenced history. | |
458 | */ | |
459 | ClearPageReferenced(page); | |
460 | test_and_clear_page_young(page); | |
461 | if (pageout) { | |
462 | if (!isolate_lru_page(page)) { | |
463 | if (PageUnevictable(page)) | |
464 | putback_lru_page(page); | |
465 | else | |
466 | list_add(&page->lru, &page_list); | |
467 | } | |
468 | } else | |
469 | deactivate_page(page); | |
470 | } | |
471 | ||
472 | arch_leave_lazy_mmu_mode(); | |
473 | pte_unmap_unlock(orig_pte, ptl); | |
474 | if (pageout) | |
475 | reclaim_pages(&page_list); | |
476 | cond_resched(); | |
477 | ||
478 | return 0; | |
479 | } | |
480 | ||
481 | static const struct mm_walk_ops cold_walk_ops = { | |
482 | .pmd_entry = madvise_cold_or_pageout_pte_range, | |
483 | }; | |
484 | ||
485 | static void madvise_cold_page_range(struct mmu_gather *tlb, | |
486 | struct vm_area_struct *vma, | |
487 | unsigned long addr, unsigned long end) | |
488 | { | |
489 | struct madvise_walk_private walk_private = { | |
490 | .pageout = false, | |
491 | .tlb = tlb, | |
492 | }; | |
493 | ||
494 | tlb_start_vma(tlb, vma); | |
495 | walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private); | |
496 | tlb_end_vma(tlb, vma); | |
497 | } | |
498 | ||
499 | static long madvise_cold(struct vm_area_struct *vma, | |
500 | struct vm_area_struct **prev, | |
501 | unsigned long start_addr, unsigned long end_addr) | |
502 | { | |
503 | struct mm_struct *mm = vma->vm_mm; | |
504 | struct mmu_gather tlb; | |
505 | ||
506 | *prev = vma; | |
507 | if (!can_madv_lru_vma(vma)) | |
508 | return -EINVAL; | |
509 | ||
510 | lru_add_drain(); | |
511 | tlb_gather_mmu(&tlb, mm); | |
512 | madvise_cold_page_range(&tlb, vma, start_addr, end_addr); | |
513 | tlb_finish_mmu(&tlb); | |
514 | ||
515 | return 0; | |
516 | } | |
517 | ||
518 | static void madvise_pageout_page_range(struct mmu_gather *tlb, | |
519 | struct vm_area_struct *vma, | |
520 | unsigned long addr, unsigned long end) | |
521 | { | |
522 | struct madvise_walk_private walk_private = { | |
523 | .pageout = true, | |
524 | .tlb = tlb, | |
525 | }; | |
526 | ||
527 | tlb_start_vma(tlb, vma); | |
528 | walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private); | |
529 | tlb_end_vma(tlb, vma); | |
530 | } | |
531 | ||
532 | static inline bool can_do_pageout(struct vm_area_struct *vma) | |
533 | { | |
534 | if (vma_is_anonymous(vma)) | |
535 | return true; | |
536 | if (!vma->vm_file) | |
537 | return false; | |
538 | /* | |
539 | * paging out pagecache only for non-anonymous mappings that correspond | |
540 | * to the files the calling process could (if tried) open for writing; | |
541 | * otherwise we'd be including shared non-exclusive mappings, which | |
542 | * opens a side channel. | |
543 | */ | |
544 | return inode_owner_or_capable(&init_user_ns, | |
545 | file_inode(vma->vm_file)) || | |
546 | file_permission(vma->vm_file, MAY_WRITE) == 0; | |
547 | } | |
548 | ||
549 | static long madvise_pageout(struct vm_area_struct *vma, | |
550 | struct vm_area_struct **prev, | |
551 | unsigned long start_addr, unsigned long end_addr) | |
552 | { | |
553 | struct mm_struct *mm = vma->vm_mm; | |
554 | struct mmu_gather tlb; | |
555 | ||
556 | *prev = vma; | |
557 | if (!can_madv_lru_vma(vma)) | |
558 | return -EINVAL; | |
559 | ||
560 | if (!can_do_pageout(vma)) | |
561 | return 0; | |
562 | ||
563 | lru_add_drain(); | |
564 | tlb_gather_mmu(&tlb, mm); | |
565 | madvise_pageout_page_range(&tlb, vma, start_addr, end_addr); | |
566 | tlb_finish_mmu(&tlb); | |
567 | ||
568 | return 0; | |
569 | } | |
570 | ||
571 | static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, | |
572 | unsigned long end, struct mm_walk *walk) | |
573 | ||
574 | { | |
575 | struct mmu_gather *tlb = walk->private; | |
576 | struct mm_struct *mm = tlb->mm; | |
577 | struct vm_area_struct *vma = walk->vma; | |
578 | spinlock_t *ptl; | |
579 | pte_t *orig_pte, *pte, ptent; | |
580 | struct page *page; | |
581 | int nr_swap = 0; | |
582 | unsigned long next; | |
583 | ||
584 | next = pmd_addr_end(addr, end); | |
585 | if (pmd_trans_huge(*pmd)) | |
586 | if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next)) | |
587 | goto next; | |
588 | ||
589 | if (pmd_trans_unstable(pmd)) | |
590 | return 0; | |
591 | ||
592 | tlb_change_page_size(tlb, PAGE_SIZE); | |
593 | orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); | |
594 | flush_tlb_batched_pending(mm); | |
595 | arch_enter_lazy_mmu_mode(); | |
596 | for (; addr != end; pte++, addr += PAGE_SIZE) { | |
597 | ptent = *pte; | |
598 | ||
599 | if (pte_none(ptent)) | |
600 | continue; | |
601 | /* | |
602 | * If the pte has swp_entry, just clear page table to | |
603 | * prevent swap-in which is more expensive rather than | |
604 | * (page allocation + zeroing). | |
605 | */ | |
606 | if (!pte_present(ptent)) { | |
607 | swp_entry_t entry; | |
608 | ||
609 | entry = pte_to_swp_entry(ptent); | |
610 | if (non_swap_entry(entry)) | |
611 | continue; | |
612 | nr_swap--; | |
613 | free_swap_and_cache(entry); | |
614 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); | |
615 | continue; | |
616 | } | |
617 | ||
618 | page = vm_normal_page(vma, addr, ptent); | |
619 | if (!page) | |
620 | continue; | |
621 | ||
622 | /* | |
623 | * If pmd isn't transhuge but the page is THP and | |
624 | * is owned by only this process, split it and | |
625 | * deactivate all pages. | |
626 | */ | |
627 | if (PageTransCompound(page)) { | |
628 | if (page_mapcount(page) != 1) | |
629 | goto out; | |
630 | get_page(page); | |
631 | if (!trylock_page(page)) { | |
632 | put_page(page); | |
633 | goto out; | |
634 | } | |
635 | pte_unmap_unlock(orig_pte, ptl); | |
636 | if (split_huge_page(page)) { | |
637 | unlock_page(page); | |
638 | put_page(page); | |
639 | pte_offset_map_lock(mm, pmd, addr, &ptl); | |
640 | goto out; | |
641 | } | |
642 | unlock_page(page); | |
643 | put_page(page); | |
644 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); | |
645 | pte--; | |
646 | addr -= PAGE_SIZE; | |
647 | continue; | |
648 | } | |
649 | ||
650 | VM_BUG_ON_PAGE(PageTransCompound(page), page); | |
651 | ||
652 | if (PageSwapCache(page) || PageDirty(page)) { | |
653 | if (!trylock_page(page)) | |
654 | continue; | |
655 | /* | |
656 | * If page is shared with others, we couldn't clear | |
657 | * PG_dirty of the page. | |
658 | */ | |
659 | if (page_mapcount(page) != 1) { | |
660 | unlock_page(page); | |
661 | continue; | |
662 | } | |
663 | ||
664 | if (PageSwapCache(page) && !try_to_free_swap(page)) { | |
665 | unlock_page(page); | |
666 | continue; | |
667 | } | |
668 | ||
669 | ClearPageDirty(page); | |
670 | unlock_page(page); | |
671 | } | |
672 | ||
673 | if (pte_young(ptent) || pte_dirty(ptent)) { | |
674 | /* | |
675 | * Some of architecture(ex, PPC) don't update TLB | |
676 | * with set_pte_at and tlb_remove_tlb_entry so for | |
677 | * the portability, remap the pte with old|clean | |
678 | * after pte clearing. | |
679 | */ | |
680 | ptent = ptep_get_and_clear_full(mm, addr, pte, | |
681 | tlb->fullmm); | |
682 | ||
683 | ptent = pte_mkold(ptent); | |
684 | ptent = pte_mkclean(ptent); | |
685 | set_pte_at(mm, addr, pte, ptent); | |
686 | tlb_remove_tlb_entry(tlb, pte, addr); | |
687 | } | |
688 | mark_page_lazyfree(page); | |
689 | } | |
690 | out: | |
691 | if (nr_swap) { | |
692 | if (current->mm == mm) | |
693 | sync_mm_rss(mm); | |
694 | ||
695 | add_mm_counter(mm, MM_SWAPENTS, nr_swap); | |
696 | } | |
697 | arch_leave_lazy_mmu_mode(); | |
698 | pte_unmap_unlock(orig_pte, ptl); | |
699 | cond_resched(); | |
700 | next: | |
701 | return 0; | |
702 | } | |
703 | ||
704 | static const struct mm_walk_ops madvise_free_walk_ops = { | |
705 | .pmd_entry = madvise_free_pte_range, | |
706 | }; | |
707 | ||
708 | static int madvise_free_single_vma(struct vm_area_struct *vma, | |
709 | unsigned long start_addr, unsigned long end_addr) | |
710 | { | |
711 | struct mm_struct *mm = vma->vm_mm; | |
712 | struct mmu_notifier_range range; | |
713 | struct mmu_gather tlb; | |
714 | ||
715 | /* MADV_FREE works for only anon vma at the moment */ | |
716 | if (!vma_is_anonymous(vma)) | |
717 | return -EINVAL; | |
718 | ||
719 | range.start = max(vma->vm_start, start_addr); | |
720 | if (range.start >= vma->vm_end) | |
721 | return -EINVAL; | |
722 | range.end = min(vma->vm_end, end_addr); | |
723 | if (range.end <= vma->vm_start) | |
724 | return -EINVAL; | |
725 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, | |
726 | range.start, range.end); | |
727 | ||
728 | lru_add_drain(); | |
729 | tlb_gather_mmu(&tlb, mm); | |
730 | update_hiwater_rss(mm); | |
731 | ||
732 | mmu_notifier_invalidate_range_start(&range); | |
733 | tlb_start_vma(&tlb, vma); | |
734 | walk_page_range(vma->vm_mm, range.start, range.end, | |
735 | &madvise_free_walk_ops, &tlb); | |
736 | tlb_end_vma(&tlb, vma); | |
737 | mmu_notifier_invalidate_range_end(&range); | |
738 | tlb_finish_mmu(&tlb); | |
739 | ||
740 | return 0; | |
741 | } | |
742 | ||
743 | /* | |
744 | * Application no longer needs these pages. If the pages are dirty, | |
745 | * it's OK to just throw them away. The app will be more careful about | |
746 | * data it wants to keep. Be sure to free swap resources too. The | |
747 | * zap_page_range call sets things up for shrink_active_list to actually free | |
748 | * these pages later if no one else has touched them in the meantime, | |
749 | * although we could add these pages to a global reuse list for | |
750 | * shrink_active_list to pick up before reclaiming other pages. | |
751 | * | |
752 | * NB: This interface discards data rather than pushes it out to swap, | |
753 | * as some implementations do. This has performance implications for | |
754 | * applications like large transactional databases which want to discard | |
755 | * pages in anonymous maps after committing to backing store the data | |
756 | * that was kept in them. There is no reason to write this data out to | |
757 | * the swap area if the application is discarding it. | |
758 | * | |
759 | * An interface that causes the system to free clean pages and flush | |
760 | * dirty pages is already available as msync(MS_INVALIDATE). | |
761 | */ | |
762 | static long madvise_dontneed_single_vma(struct vm_area_struct *vma, | |
763 | unsigned long start, unsigned long end) | |
764 | { | |
765 | zap_page_range(vma, start, end - start); | |
766 | return 0; | |
767 | } | |
768 | ||
769 | static long madvise_dontneed_free(struct vm_area_struct *vma, | |
770 | struct vm_area_struct **prev, | |
771 | unsigned long start, unsigned long end, | |
772 | int behavior) | |
773 | { | |
774 | struct mm_struct *mm = vma->vm_mm; | |
775 | ||
776 | *prev = vma; | |
777 | if (!can_madv_lru_vma(vma)) | |
778 | return -EINVAL; | |
779 | ||
780 | if (!userfaultfd_remove(vma, start, end)) { | |
781 | *prev = NULL; /* mmap_lock has been dropped, prev is stale */ | |
782 | ||
783 | mmap_read_lock(mm); | |
784 | vma = find_vma(mm, start); | |
785 | if (!vma) | |
786 | return -ENOMEM; | |
787 | if (start < vma->vm_start) { | |
788 | /* | |
789 | * This "vma" under revalidation is the one | |
790 | * with the lowest vma->vm_start where start | |
791 | * is also < vma->vm_end. If start < | |
792 | * vma->vm_start it means an hole materialized | |
793 | * in the user address space within the | |
794 | * virtual range passed to MADV_DONTNEED | |
795 | * or MADV_FREE. | |
796 | */ | |
797 | return -ENOMEM; | |
798 | } | |
799 | if (!can_madv_lru_vma(vma)) | |
800 | return -EINVAL; | |
801 | if (end > vma->vm_end) { | |
802 | /* | |
803 | * Don't fail if end > vma->vm_end. If the old | |
804 | * vma was split while the mmap_lock was | |
805 | * released the effect of the concurrent | |
806 | * operation may not cause madvise() to | |
807 | * have an undefined result. There may be an | |
808 | * adjacent next vma that we'll walk | |
809 | * next. userfaultfd_remove() will generate an | |
810 | * UFFD_EVENT_REMOVE repetition on the | |
811 | * end-vma->vm_end range, but the manager can | |
812 | * handle a repetition fine. | |
813 | */ | |
814 | end = vma->vm_end; | |
815 | } | |
816 | VM_WARN_ON(start >= end); | |
817 | } | |
818 | ||
819 | if (behavior == MADV_DONTNEED) | |
820 | return madvise_dontneed_single_vma(vma, start, end); | |
821 | else if (behavior == MADV_FREE) | |
822 | return madvise_free_single_vma(vma, start, end); | |
823 | else | |
824 | return -EINVAL; | |
825 | } | |
826 | ||
827 | static long madvise_populate(struct vm_area_struct *vma, | |
828 | struct vm_area_struct **prev, | |
829 | unsigned long start, unsigned long end, | |
830 | int behavior) | |
831 | { | |
832 | const bool write = behavior == MADV_POPULATE_WRITE; | |
833 | struct mm_struct *mm = vma->vm_mm; | |
834 | unsigned long tmp_end; | |
835 | int locked = 1; | |
836 | long pages; | |
837 | ||
838 | *prev = vma; | |
839 | ||
840 | while (start < end) { | |
841 | /* | |
842 | * We might have temporarily dropped the lock. For example, | |
843 | * our VMA might have been split. | |
844 | */ | |
845 | if (!vma || start >= vma->vm_end) { | |
846 | vma = find_vma(mm, start); | |
847 | if (!vma || start < vma->vm_start) | |
848 | return -ENOMEM; | |
849 | } | |
850 | ||
851 | tmp_end = min_t(unsigned long, end, vma->vm_end); | |
852 | /* Populate (prefault) page tables readable/writable. */ | |
853 | pages = faultin_vma_page_range(vma, start, tmp_end, write, | |
854 | &locked); | |
855 | if (!locked) { | |
856 | mmap_read_lock(mm); | |
857 | locked = 1; | |
858 | *prev = NULL; | |
859 | vma = NULL; | |
860 | } | |
861 | if (pages < 0) { | |
862 | switch (pages) { | |
863 | case -EINTR: | |
864 | return -EINTR; | |
865 | case -EINVAL: /* Incompatible mappings / permissions. */ | |
866 | return -EINVAL; | |
867 | case -EHWPOISON: | |
868 | return -EHWPOISON; | |
869 | case -EFAULT: /* VM_FAULT_SIGBUS or VM_FAULT_SIGSEGV */ | |
870 | return -EFAULT; | |
871 | default: | |
872 | pr_warn_once("%s: unhandled return value: %ld\n", | |
873 | __func__, pages); | |
874 | fallthrough; | |
875 | case -ENOMEM: | |
876 | return -ENOMEM; | |
877 | } | |
878 | } | |
879 | start += pages * PAGE_SIZE; | |
880 | } | |
881 | return 0; | |
882 | } | |
883 | ||
884 | /* | |
885 | * Application wants to free up the pages and associated backing store. | |
886 | * This is effectively punching a hole into the middle of a file. | |
887 | */ | |
888 | static long madvise_remove(struct vm_area_struct *vma, | |
889 | struct vm_area_struct **prev, | |
890 | unsigned long start, unsigned long end) | |
891 | { | |
892 | loff_t offset; | |
893 | int error; | |
894 | struct file *f; | |
895 | struct mm_struct *mm = vma->vm_mm; | |
896 | ||
897 | *prev = NULL; /* tell sys_madvise we drop mmap_lock */ | |
898 | ||
899 | if (vma->vm_flags & VM_LOCKED) | |
900 | return -EINVAL; | |
901 | ||
902 | f = vma->vm_file; | |
903 | ||
904 | if (!f || !f->f_mapping || !f->f_mapping->host) { | |
905 | return -EINVAL; | |
906 | } | |
907 | ||
908 | if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE)) | |
909 | return -EACCES; | |
910 | ||
911 | offset = (loff_t)(start - vma->vm_start) | |
912 | + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); | |
913 | ||
914 | /* | |
915 | * Filesystem's fallocate may need to take i_mutex. We need to | |
916 | * explicitly grab a reference because the vma (and hence the | |
917 | * vma's reference to the file) can go away as soon as we drop | |
918 | * mmap_lock. | |
919 | */ | |
920 | get_file(f); | |
921 | if (userfaultfd_remove(vma, start, end)) { | |
922 | /* mmap_lock was not released by userfaultfd_remove() */ | |
923 | mmap_read_unlock(mm); | |
924 | } | |
925 | error = vfs_fallocate(f, | |
926 | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, | |
927 | offset, end - start); | |
928 | fput(f); | |
929 | mmap_read_lock(mm); | |
930 | return error; | |
931 | } | |
932 | ||
933 | #ifdef CONFIG_MEMORY_FAILURE | |
934 | /* | |
935 | * Error injection support for memory error handling. | |
936 | */ | |
937 | static int madvise_inject_error(int behavior, | |
938 | unsigned long start, unsigned long end) | |
939 | { | |
940 | unsigned long size; | |
941 | ||
942 | if (!capable(CAP_SYS_ADMIN)) | |
943 | return -EPERM; | |
944 | ||
945 | ||
946 | for (; start < end; start += size) { | |
947 | unsigned long pfn; | |
948 | struct page *page; | |
949 | int ret; | |
950 | ||
951 | ret = get_user_pages_fast(start, 1, 0, &page); | |
952 | if (ret != 1) | |
953 | return ret; | |
954 | pfn = page_to_pfn(page); | |
955 | ||
956 | /* | |
957 | * When soft offlining hugepages, after migrating the page | |
958 | * we dissolve it, therefore in the second loop "page" will | |
959 | * no longer be a compound page. | |
960 | */ | |
961 | size = page_size(compound_head(page)); | |
962 | ||
963 | if (behavior == MADV_SOFT_OFFLINE) { | |
964 | pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n", | |
965 | pfn, start); | |
966 | ret = soft_offline_page(pfn, MF_COUNT_INCREASED); | |
967 | } else { | |
968 | pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", | |
969 | pfn, start); | |
970 | ret = memory_failure(pfn, MF_COUNT_INCREASED); | |
971 | } | |
972 | ||
973 | if (ret) | |
974 | return ret; | |
975 | } | |
976 | ||
977 | return 0; | |
978 | } | |
979 | #endif | |
980 | ||
981 | static long | |
982 | madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, | |
983 | unsigned long start, unsigned long end, int behavior) | |
984 | { | |
985 | switch (behavior) { | |
986 | case MADV_REMOVE: | |
987 | return madvise_remove(vma, prev, start, end); | |
988 | case MADV_WILLNEED: | |
989 | return madvise_willneed(vma, prev, start, end); | |
990 | case MADV_COLD: | |
991 | return madvise_cold(vma, prev, start, end); | |
992 | case MADV_PAGEOUT: | |
993 | return madvise_pageout(vma, prev, start, end); | |
994 | case MADV_FREE: | |
995 | case MADV_DONTNEED: | |
996 | return madvise_dontneed_free(vma, prev, start, end, behavior); | |
997 | case MADV_POPULATE_READ: | |
998 | case MADV_POPULATE_WRITE: | |
999 | return madvise_populate(vma, prev, start, end, behavior); | |
1000 | default: | |
1001 | return madvise_behavior(vma, prev, start, end, behavior); | |
1002 | } | |
1003 | } | |
1004 | ||
1005 | static bool | |
1006 | madvise_behavior_valid(int behavior) | |
1007 | { | |
1008 | switch (behavior) { | |
1009 | case MADV_DOFORK: | |
1010 | case MADV_DONTFORK: | |
1011 | case MADV_NORMAL: | |
1012 | case MADV_SEQUENTIAL: | |
1013 | case MADV_RANDOM: | |
1014 | case MADV_REMOVE: | |
1015 | case MADV_WILLNEED: | |
1016 | case MADV_DONTNEED: | |
1017 | case MADV_FREE: | |
1018 | case MADV_COLD: | |
1019 | case MADV_PAGEOUT: | |
1020 | case MADV_POPULATE_READ: | |
1021 | case MADV_POPULATE_WRITE: | |
1022 | #ifdef CONFIG_KSM | |
1023 | case MADV_MERGEABLE: | |
1024 | case MADV_UNMERGEABLE: | |
1025 | #endif | |
1026 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE | |
1027 | case MADV_HUGEPAGE: | |
1028 | case MADV_NOHUGEPAGE: | |
1029 | #endif | |
1030 | case MADV_DONTDUMP: | |
1031 | case MADV_DODUMP: | |
1032 | case MADV_WIPEONFORK: | |
1033 | case MADV_KEEPONFORK: | |
1034 | #ifdef CONFIG_MEMORY_FAILURE | |
1035 | case MADV_SOFT_OFFLINE: | |
1036 | case MADV_HWPOISON: | |
1037 | #endif | |
1038 | return true; | |
1039 | ||
1040 | default: | |
1041 | return false; | |
1042 | } | |
1043 | } | |
1044 | ||
1045 | static bool | |
1046 | process_madvise_behavior_valid(int behavior) | |
1047 | { | |
1048 | switch (behavior) { | |
1049 | case MADV_COLD: | |
1050 | case MADV_PAGEOUT: | |
1051 | return true; | |
1052 | default: | |
1053 | return false; | |
1054 | } | |
1055 | } | |
1056 | ||
1057 | /* | |
1058 | * The madvise(2) system call. | |
1059 | * | |
1060 | * Applications can use madvise() to advise the kernel how it should | |
1061 | * handle paging I/O in this VM area. The idea is to help the kernel | |
1062 | * use appropriate read-ahead and caching techniques. The information | |
1063 | * provided is advisory only, and can be safely disregarded by the | |
1064 | * kernel without affecting the correct operation of the application. | |
1065 | * | |
1066 | * behavior values: | |
1067 | * MADV_NORMAL - the default behavior is to read clusters. This | |
1068 | * results in some read-ahead and read-behind. | |
1069 | * MADV_RANDOM - the system should read the minimum amount of data | |
1070 | * on any access, since it is unlikely that the appli- | |
1071 | * cation will need more than what it asks for. | |
1072 | * MADV_SEQUENTIAL - pages in the given range will probably be accessed | |
1073 | * once, so they can be aggressively read ahead, and | |
1074 | * can be freed soon after they are accessed. | |
1075 | * MADV_WILLNEED - the application is notifying the system to read | |
1076 | * some pages ahead. | |
1077 | * MADV_DONTNEED - the application is finished with the given range, | |
1078 | * so the kernel can free resources associated with it. | |
1079 | * MADV_FREE - the application marks pages in the given range as lazy free, | |
1080 | * where actual purges are postponed until memory pressure happens. | |
1081 | * MADV_REMOVE - the application wants to free up the given range of | |
1082 | * pages and associated backing store. | |
1083 | * MADV_DONTFORK - omit this area from child's address space when forking: | |
1084 | * typically, to avoid COWing pages pinned by get_user_pages(). | |
1085 | * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking. | |
1086 | * MADV_WIPEONFORK - present the child process with zero-filled memory in this | |
1087 | * range after a fork. | |
1088 | * MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK | |
1089 | * MADV_HWPOISON - trigger memory error handler as if the given memory range | |
1090 | * were corrupted by unrecoverable hardware memory failure. | |
1091 | * MADV_SOFT_OFFLINE - try to soft-offline the given range of memory. | |
1092 | * MADV_MERGEABLE - the application recommends that KSM try to merge pages in | |
1093 | * this area with pages of identical content from other such areas. | |
1094 | * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others. | |
1095 | * MADV_HUGEPAGE - the application wants to back the given range by transparent | |
1096 | * huge pages in the future. Existing pages might be coalesced and | |
1097 | * new pages might be allocated as THP. | |
1098 | * MADV_NOHUGEPAGE - mark the given range as not worth being backed by | |
1099 | * transparent huge pages so the existing pages will not be | |
1100 | * coalesced into THP and new pages will not be allocated as THP. | |
1101 | * MADV_DONTDUMP - the application wants to prevent pages in the given range | |
1102 | * from being included in its core dump. | |
1103 | * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump. | |
1104 | * MADV_COLD - the application is not expected to use this memory soon, | |
1105 | * deactivate pages in this range so that they can be reclaimed | |
1106 | * easily if memory pressure happens. | |
1107 | * MADV_PAGEOUT - the application is not expected to use this memory soon, | |
1108 | * page out the pages in this range immediately. | |
1109 | * MADV_POPULATE_READ - populate (prefault) page tables readable by | |
1110 | * triggering read faults if required | |
1111 | * MADV_POPULATE_WRITE - populate (prefault) page tables writable by | |
1112 | * triggering write faults if required | |
1113 | * | |
1114 | * return values: | |
1115 | * zero - success | |
1116 | * -EINVAL - start + len < 0, start is not page-aligned, | |
1117 | * "behavior" is not a valid value, or application | |
1118 | * is attempting to release locked or shared pages, | |
1119 | * or the specified address range includes file, Huge TLB, | |
1120 | * MAP_SHARED or VMPFNMAP range. | |
1121 | * -ENOMEM - addresses in the specified range are not currently | |
1122 | * mapped, or are outside the AS of the process. | |
1123 | * -EIO - an I/O error occurred while paging in data. | |
1124 | * -EBADF - map exists, but area maps something that isn't a file. | |
1125 | * -EAGAIN - a kernel resource was temporarily unavailable. | |
1126 | */ | |
1127 | int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior) | |
1128 | { | |
1129 | unsigned long end, tmp; | |
1130 | struct vm_area_struct *vma, *prev; | |
1131 | int unmapped_error = 0; | |
1132 | int error = -EINVAL; | |
1133 | int write; | |
1134 | size_t len; | |
1135 | struct blk_plug plug; | |
1136 | ||
1137 | start = untagged_addr(start); | |
1138 | ||
1139 | if (!madvise_behavior_valid(behavior)) | |
1140 | return error; | |
1141 | ||
1142 | if (!PAGE_ALIGNED(start)) | |
1143 | return error; | |
1144 | len = PAGE_ALIGN(len_in); | |
1145 | ||
1146 | /* Check to see whether len was rounded up from small -ve to zero */ | |
1147 | if (len_in && !len) | |
1148 | return error; | |
1149 | ||
1150 | end = start + len; | |
1151 | if (end < start) | |
1152 | return error; | |
1153 | ||
1154 | error = 0; | |
1155 | if (end == start) | |
1156 | return error; | |
1157 | ||
1158 | #ifdef CONFIG_MEMORY_FAILURE | |
1159 | if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE) | |
1160 | return madvise_inject_error(behavior, start, start + len_in); | |
1161 | #endif | |
1162 | ||
1163 | write = madvise_need_mmap_write(behavior); | |
1164 | if (write) { | |
1165 | if (mmap_write_lock_killable(mm)) | |
1166 | return -EINTR; | |
1167 | } else { | |
1168 | mmap_read_lock(mm); | |
1169 | } | |
1170 | ||
1171 | /* | |
1172 | * If the interval [start,end) covers some unmapped address | |
1173 | * ranges, just ignore them, but return -ENOMEM at the end. | |
1174 | * - different from the way of handling in mlock etc. | |
1175 | */ | |
1176 | vma = find_vma_prev(mm, start, &prev); | |
1177 | if (vma && start > vma->vm_start) | |
1178 | prev = vma; | |
1179 | ||
1180 | blk_start_plug(&plug); | |
1181 | for (;;) { | |
1182 | /* Still start < end. */ | |
1183 | error = -ENOMEM; | |
1184 | if (!vma) | |
1185 | goto out; | |
1186 | ||
1187 | /* Here start < (end|vma->vm_end). */ | |
1188 | if (start < vma->vm_start) { | |
1189 | unmapped_error = -ENOMEM; | |
1190 | start = vma->vm_start; | |
1191 | if (start >= end) | |
1192 | goto out; | |
1193 | } | |
1194 | ||
1195 | /* Here vma->vm_start <= start < (end|vma->vm_end) */ | |
1196 | tmp = vma->vm_end; | |
1197 | if (end < tmp) | |
1198 | tmp = end; | |
1199 | ||
1200 | /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ | |
1201 | error = madvise_vma(vma, &prev, start, tmp, behavior); | |
1202 | if (error) | |
1203 | goto out; | |
1204 | start = tmp; | |
1205 | if (prev && start < prev->vm_end) | |
1206 | start = prev->vm_end; | |
1207 | error = unmapped_error; | |
1208 | if (start >= end) | |
1209 | goto out; | |
1210 | if (prev) | |
1211 | vma = prev->vm_next; | |
1212 | else /* madvise_remove dropped mmap_lock */ | |
1213 | vma = find_vma(mm, start); | |
1214 | } | |
1215 | out: | |
1216 | blk_finish_plug(&plug); | |
1217 | if (write) | |
1218 | mmap_write_unlock(mm); | |
1219 | else | |
1220 | mmap_read_unlock(mm); | |
1221 | ||
1222 | return error; | |
1223 | } | |
1224 | ||
1225 | SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) | |
1226 | { | |
1227 | return do_madvise(current->mm, start, len_in, behavior); | |
1228 | } | |
1229 | ||
1230 | SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, | |
1231 | size_t, vlen, int, behavior, unsigned int, flags) | |
1232 | { | |
1233 | ssize_t ret; | |
1234 | struct iovec iovstack[UIO_FASTIOV], iovec; | |
1235 | struct iovec *iov = iovstack; | |
1236 | struct iov_iter iter; | |
1237 | struct pid *pid; | |
1238 | struct task_struct *task; | |
1239 | struct mm_struct *mm; | |
1240 | size_t total_len; | |
1241 | unsigned int f_flags; | |
1242 | ||
1243 | if (flags != 0) { | |
1244 | ret = -EINVAL; | |
1245 | goto out; | |
1246 | } | |
1247 | ||
1248 | ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); | |
1249 | if (ret < 0) | |
1250 | goto out; | |
1251 | ||
1252 | pid = pidfd_get_pid(pidfd, &f_flags); | |
1253 | if (IS_ERR(pid)) { | |
1254 | ret = PTR_ERR(pid); | |
1255 | goto free_iov; | |
1256 | } | |
1257 | ||
1258 | task = get_pid_task(pid, PIDTYPE_PID); | |
1259 | if (!task) { | |
1260 | ret = -ESRCH; | |
1261 | goto put_pid; | |
1262 | } | |
1263 | ||
1264 | if (!process_madvise_behavior_valid(behavior)) { | |
1265 | ret = -EINVAL; | |
1266 | goto release_task; | |
1267 | } | |
1268 | ||
1269 | /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */ | |
1270 | mm = mm_access(task, PTRACE_MODE_READ_FSCREDS); | |
1271 | if (IS_ERR_OR_NULL(mm)) { | |
1272 | ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH; | |
1273 | goto release_task; | |
1274 | } | |
1275 | ||
1276 | /* | |
1277 | * Require CAP_SYS_NICE for influencing process performance. Note that | |
1278 | * only non-destructive hints are currently supported. | |
1279 | */ | |
1280 | if (!capable(CAP_SYS_NICE)) { | |
1281 | ret = -EPERM; | |
1282 | goto release_mm; | |
1283 | } | |
1284 | ||
1285 | total_len = iov_iter_count(&iter); | |
1286 | ||
1287 | while (iov_iter_count(&iter)) { | |
1288 | iovec = iov_iter_iovec(&iter); | |
1289 | ret = do_madvise(mm, (unsigned long)iovec.iov_base, | |
1290 | iovec.iov_len, behavior); | |
1291 | if (ret < 0) | |
1292 | break; | |
1293 | iov_iter_advance(&iter, iovec.iov_len); | |
1294 | } | |
1295 | ||
1296 | if (ret == 0) | |
1297 | ret = total_len - iov_iter_count(&iter); | |
1298 | ||
1299 | release_mm: | |
1300 | mmput(mm); | |
1301 | release_task: | |
1302 | put_task_struct(task); | |
1303 | put_pid: | |
1304 | put_pid(pid); | |
1305 | free_iov: | |
1306 | kfree(iov); | |
1307 | out: | |
1308 | return ret; | |
1309 | } |