Line data Source code
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/mm_inline.h>
22 : #include <linux/string.h>
23 : #include <linux/uio.h>
24 : #include <linux/ksm.h>
25 : #include <linux/fs.h>
26 : #include <linux/file.h>
27 : #include <linux/blkdev.h>
28 : #include <linux/backing-dev.h>
29 : #include <linux/pagewalk.h>
30 : #include <linux/swap.h>
31 : #include <linux/swapops.h>
32 : #include <linux/shmem_fs.h>
33 : #include <linux/mmu_notifier.h>
34 :
35 : #include <asm/tlb.h>
36 :
37 : #include "internal.h"
38 : #include "swap.h"
39 :
40 : struct madvise_walk_private {
41 : struct mmu_gather *tlb;
42 : bool pageout;
43 : };
44 :
45 : /*
46 : * Any behaviour which results in changes to the vma->vm_flags needs to
47 : * take mmap_lock for writing. Others, which simply traverse vmas, need
48 : * to only take it for reading.
49 : */
50 : static int madvise_need_mmap_write(int behavior)
51 : {
52 : switch (behavior) {
53 : case MADV_REMOVE:
54 : case MADV_WILLNEED:
55 : case MADV_DONTNEED:
56 : case MADV_DONTNEED_LOCKED:
57 : case MADV_COLD:
58 : case MADV_PAGEOUT:
59 : case MADV_FREE:
60 : case MADV_POPULATE_READ:
61 : case MADV_POPULATE_WRITE:
62 : case MADV_COLLAPSE:
63 : return 0;
64 : default:
65 : /* be safe, default to 1. list exceptions explicitly */
66 : return 1;
67 : }
68 : }
69 :
70 : #ifdef CONFIG_ANON_VMA_NAME
71 : struct anon_vma_name *anon_vma_name_alloc(const char *name)
72 : {
73 : struct anon_vma_name *anon_name;
74 : size_t count;
75 :
76 : /* Add 1 for NUL terminator at the end of the anon_name->name */
77 : count = strlen(name) + 1;
78 : anon_name = kmalloc(struct_size(anon_name, name, count), GFP_KERNEL);
79 : if (anon_name) {
80 : kref_init(&anon_name->kref);
81 : memcpy(anon_name->name, name, count);
82 : }
83 :
84 : return anon_name;
85 : }
86 :
87 : void anon_vma_name_free(struct kref *kref)
88 : {
89 : struct anon_vma_name *anon_name =
90 : container_of(kref, struct anon_vma_name, kref);
91 : kfree(anon_name);
92 : }
93 :
94 : struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
95 : {
96 : mmap_assert_locked(vma->vm_mm);
97 :
98 : return vma->anon_name;
99 : }
100 :
101 : /* mmap_lock should be write-locked */
102 : static int replace_anon_vma_name(struct vm_area_struct *vma,
103 : struct anon_vma_name *anon_name)
104 : {
105 : struct anon_vma_name *orig_name = anon_vma_name(vma);
106 :
107 : if (!anon_name) {
108 : vma->anon_name = NULL;
109 : anon_vma_name_put(orig_name);
110 : return 0;
111 : }
112 :
113 : if (anon_vma_name_eq(orig_name, anon_name))
114 : return 0;
115 :
116 : vma->anon_name = anon_vma_name_reuse(anon_name);
117 : anon_vma_name_put(orig_name);
118 :
119 : return 0;
120 : }
121 : #else /* CONFIG_ANON_VMA_NAME */
122 : static int replace_anon_vma_name(struct vm_area_struct *vma,
123 : struct anon_vma_name *anon_name)
124 : {
125 0 : if (anon_name)
126 : return -EINVAL;
127 :
128 : return 0;
129 : }
130 : #endif /* CONFIG_ANON_VMA_NAME */
131 : /*
132 : * Update the vm_flags on region of a vma, splitting it or merging it as
133 : * necessary. Must be called with mmap_lock held for writing;
134 : * Caller should ensure anon_name stability by raising its refcount even when
135 : * anon_name belongs to a valid vma because this function might free that vma.
136 : */
137 0 : static int madvise_update_vma(struct vm_area_struct *vma,
138 : struct vm_area_struct **prev, unsigned long start,
139 : unsigned long end, unsigned long new_flags,
140 : struct anon_vma_name *anon_name)
141 : {
142 0 : struct mm_struct *mm = vma->vm_mm;
143 : int error;
144 : pgoff_t pgoff;
145 0 : VMA_ITERATOR(vmi, mm, start);
146 :
147 0 : if (new_flags == vma->vm_flags && anon_vma_name_eq(anon_vma_name(vma), anon_name)) {
148 0 : *prev = vma;
149 0 : return 0;
150 : }
151 :
152 0 : pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
153 0 : *prev = vma_merge(&vmi, mm, *prev, start, end, new_flags,
154 : vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
155 : vma->vm_userfaultfd_ctx, anon_name);
156 0 : if (*prev) {
157 : vma = *prev;
158 : goto success;
159 : }
160 :
161 0 : *prev = vma;
162 :
163 0 : if (start != vma->vm_start) {
164 0 : error = split_vma(&vmi, vma, start, 1);
165 0 : if (error)
166 : return error;
167 : }
168 :
169 0 : if (end != vma->vm_end) {
170 0 : error = split_vma(&vmi, vma, end, 0);
171 0 : if (error)
172 : return error;
173 : }
174 :
175 : success:
176 : /*
177 : * vm_flags is protected by the mmap_lock held in write mode.
178 : */
179 0 : vm_flags_reset(vma, new_flags);
180 0 : if (!vma->vm_file || vma_is_anon_shmem(vma)) {
181 0 : error = replace_anon_vma_name(vma, anon_name);
182 0 : if (error)
183 : return error;
184 : }
185 :
186 : return 0;
187 : }
188 :
189 : #ifdef CONFIG_SWAP
190 0 : static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
191 : unsigned long end, struct mm_walk *walk)
192 : {
193 0 : struct vm_area_struct *vma = walk->private;
194 0 : struct swap_iocb *splug = NULL;
195 0 : pte_t *ptep = NULL;
196 : spinlock_t *ptl;
197 : unsigned long addr;
198 :
199 0 : for (addr = start; addr < end; addr += PAGE_SIZE) {
200 : pte_t pte;
201 : swp_entry_t entry;
202 : struct page *page;
203 :
204 0 : if (!ptep++) {
205 0 : ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
206 0 : if (!ptep)
207 : break;
208 : }
209 :
210 0 : pte = ptep_get(ptep);
211 0 : if (!is_swap_pte(pte))
212 0 : continue;
213 0 : entry = pte_to_swp_entry(pte);
214 0 : if (unlikely(non_swap_entry(entry)))
215 0 : continue;
216 :
217 0 : pte_unmap_unlock(ptep, ptl);
218 0 : ptep = NULL;
219 :
220 0 : page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE,
221 : vma, addr, false, &splug);
222 0 : if (page)
223 0 : put_page(page);
224 : }
225 :
226 0 : if (ptep)
227 0 : pte_unmap_unlock(ptep, ptl);
228 0 : swap_read_unplug(splug);
229 0 : cond_resched();
230 :
231 0 : return 0;
232 : }
233 :
234 : static const struct mm_walk_ops swapin_walk_ops = {
235 : .pmd_entry = swapin_walk_pmd_entry,
236 : };
237 :
238 0 : static void shmem_swapin_range(struct vm_area_struct *vma,
239 : unsigned long start, unsigned long end,
240 : struct address_space *mapping)
241 : {
242 0 : XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start));
243 0 : pgoff_t end_index = linear_page_index(vma, end) - 1;
244 : struct page *page;
245 0 : struct swap_iocb *splug = NULL;
246 :
247 : rcu_read_lock();
248 0 : xas_for_each(&xas, page, end_index) {
249 : unsigned long addr;
250 : swp_entry_t entry;
251 :
252 0 : if (!xa_is_value(page))
253 0 : continue;
254 0 : entry = radix_to_swp_entry(page);
255 : /* There might be swapin error entries in shmem mapping. */
256 0 : if (non_swap_entry(entry))
257 0 : continue;
258 :
259 0 : addr = vma->vm_start +
260 0 : ((xas.xa_index - vma->vm_pgoff) << PAGE_SHIFT);
261 0 : xas_pause(&xas);
262 : rcu_read_unlock();
263 :
264 0 : page = read_swap_cache_async(entry, mapping_gfp_mask(mapping),
265 : vma, addr, false, &splug);
266 0 : if (page)
267 0 : put_page(page);
268 :
269 : rcu_read_lock();
270 : }
271 : rcu_read_unlock();
272 0 : swap_read_unplug(splug);
273 0 : }
274 : #endif /* CONFIG_SWAP */
275 :
276 : /*
277 : * Schedule all required I/O operations. Do not wait for completion.
278 : */
279 0 : static long madvise_willneed(struct vm_area_struct *vma,
280 : struct vm_area_struct **prev,
281 : unsigned long start, unsigned long end)
282 : {
283 0 : struct mm_struct *mm = vma->vm_mm;
284 0 : struct file *file = vma->vm_file;
285 : loff_t offset;
286 :
287 0 : *prev = vma;
288 : #ifdef CONFIG_SWAP
289 0 : if (!file) {
290 0 : walk_page_range(vma->vm_mm, start, end, &swapin_walk_ops, vma);
291 0 : lru_add_drain(); /* Push any new pages onto the LRU now */
292 0 : return 0;
293 : }
294 :
295 0 : if (shmem_mapping(file->f_mapping)) {
296 0 : shmem_swapin_range(vma, start, end, file->f_mapping);
297 0 : lru_add_drain(); /* Push any new pages onto the LRU now */
298 0 : return 0;
299 : }
300 : #else
301 : if (!file)
302 : return -EBADF;
303 : #endif
304 :
305 0 : if (IS_DAX(file_inode(file))) {
306 : /* no bad return value, but ignore advice */
307 : return 0;
308 : }
309 :
310 : /*
311 : * Filesystem's fadvise may need to take various locks. We need to
312 : * explicitly grab a reference because the vma (and hence the
313 : * vma's reference to the file) can go away as soon as we drop
314 : * mmap_lock.
315 : */
316 0 : *prev = NULL; /* tell sys_madvise we drop mmap_lock */
317 0 : get_file(file);
318 0 : offset = (loff_t)(start - vma->vm_start)
319 0 : + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
320 0 : mmap_read_unlock(mm);
321 0 : vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED);
322 0 : fput(file);
323 0 : mmap_read_lock(mm);
324 0 : return 0;
325 : }
326 :
327 0 : static inline bool can_do_file_pageout(struct vm_area_struct *vma)
328 : {
329 0 : if (!vma->vm_file)
330 : return false;
331 : /*
332 : * paging out pagecache only for non-anonymous mappings that correspond
333 : * to the files the calling process could (if tried) open for writing;
334 : * otherwise we'd be including shared non-exclusive mappings, which
335 : * opens a side channel.
336 : */
337 0 : return inode_owner_or_capable(&nop_mnt_idmap,
338 0 : file_inode(vma->vm_file)) ||
339 0 : file_permission(vma->vm_file, MAY_WRITE) == 0;
340 : }
341 :
342 0 : static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
343 : unsigned long addr, unsigned long end,
344 : struct mm_walk *walk)
345 : {
346 0 : struct madvise_walk_private *private = walk->private;
347 0 : struct mmu_gather *tlb = private->tlb;
348 0 : bool pageout = private->pageout;
349 0 : struct mm_struct *mm = tlb->mm;
350 0 : struct vm_area_struct *vma = walk->vma;
351 : pte_t *start_pte, *pte, ptent;
352 : spinlock_t *ptl;
353 0 : struct folio *folio = NULL;
354 0 : LIST_HEAD(folio_list);
355 : bool pageout_anon_only_filter;
356 :
357 0 : if (fatal_signal_pending(current))
358 : return -EINTR;
359 :
360 0 : pageout_anon_only_filter = pageout && !vma_is_anonymous(vma) &&
361 0 : !can_do_file_pageout(vma);
362 :
363 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
364 : if (pmd_trans_huge(*pmd)) {
365 : pmd_t orig_pmd;
366 : unsigned long next = pmd_addr_end(addr, end);
367 :
368 : tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
369 : ptl = pmd_trans_huge_lock(pmd, vma);
370 : if (!ptl)
371 : return 0;
372 :
373 : orig_pmd = *pmd;
374 : if (is_huge_zero_pmd(orig_pmd))
375 : goto huge_unlock;
376 :
377 : if (unlikely(!pmd_present(orig_pmd))) {
378 : VM_BUG_ON(thp_migration_supported() &&
379 : !is_pmd_migration_entry(orig_pmd));
380 : goto huge_unlock;
381 : }
382 :
383 : folio = pfn_folio(pmd_pfn(orig_pmd));
384 :
385 : /* Do not interfere with other mappings of this folio */
386 : if (folio_mapcount(folio) != 1)
387 : goto huge_unlock;
388 :
389 : if (pageout_anon_only_filter && !folio_test_anon(folio))
390 : goto huge_unlock;
391 :
392 : if (next - addr != HPAGE_PMD_SIZE) {
393 : int err;
394 :
395 : folio_get(folio);
396 : spin_unlock(ptl);
397 : folio_lock(folio);
398 : err = split_folio(folio);
399 : folio_unlock(folio);
400 : folio_put(folio);
401 : if (!err)
402 : goto regular_folio;
403 : return 0;
404 : }
405 :
406 : if (pmd_young(orig_pmd)) {
407 : pmdp_invalidate(vma, addr, pmd);
408 : orig_pmd = pmd_mkold(orig_pmd);
409 :
410 : set_pmd_at(mm, addr, pmd, orig_pmd);
411 : tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
412 : }
413 :
414 : folio_clear_referenced(folio);
415 : folio_test_clear_young(folio);
416 : if (pageout) {
417 : if (folio_isolate_lru(folio)) {
418 : if (folio_test_unevictable(folio))
419 : folio_putback_lru(folio);
420 : else
421 : list_add(&folio->lru, &folio_list);
422 : }
423 : } else
424 : folio_deactivate(folio);
425 : huge_unlock:
426 : spin_unlock(ptl);
427 : if (pageout)
428 : reclaim_pages(&folio_list);
429 : return 0;
430 : }
431 :
432 : regular_folio:
433 : #endif
434 0 : tlb_change_page_size(tlb, PAGE_SIZE);
435 0 : start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
436 0 : if (!start_pte)
437 : return 0;
438 : flush_tlb_batched_pending(mm);
439 : arch_enter_lazy_mmu_mode();
440 0 : for (; addr < end; pte++, addr += PAGE_SIZE) {
441 0 : ptent = ptep_get(pte);
442 :
443 0 : if (pte_none(ptent))
444 0 : continue;
445 :
446 0 : if (!pte_present(ptent))
447 0 : continue;
448 :
449 0 : folio = vm_normal_folio(vma, addr, ptent);
450 0 : if (!folio || folio_is_zone_device(folio))
451 0 : continue;
452 :
453 : /*
454 : * Creating a THP page is expensive so split it only if we
455 : * are sure it's worth. Split it if we are only owner.
456 : */
457 0 : if (folio_test_large(folio)) {
458 : int err;
459 :
460 0 : if (folio_mapcount(folio) != 1)
461 : break;
462 0 : if (pageout_anon_only_filter && !folio_test_anon(folio))
463 : break;
464 0 : if (!folio_trylock(folio))
465 : break;
466 0 : folio_get(folio);
467 : arch_leave_lazy_mmu_mode();
468 0 : pte_unmap_unlock(start_pte, ptl);
469 0 : start_pte = NULL;
470 0 : err = split_folio(folio);
471 0 : folio_unlock(folio);
472 0 : folio_put(folio);
473 : if (err)
474 : break;
475 0 : start_pte = pte =
476 : pte_offset_map_lock(mm, pmd, addr, &ptl);
477 0 : if (!start_pte)
478 : break;
479 : arch_enter_lazy_mmu_mode();
480 0 : pte--;
481 0 : addr -= PAGE_SIZE;
482 0 : continue;
483 : }
484 :
485 : /*
486 : * Do not interfere with other mappings of this folio and
487 : * non-LRU folio.
488 : */
489 0 : if (!folio_test_lru(folio) || folio_mapcount(folio) != 1)
490 0 : continue;
491 :
492 0 : if (pageout_anon_only_filter && !folio_test_anon(folio))
493 0 : continue;
494 :
495 : VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
496 :
497 0 : if (pte_young(ptent)) {
498 0 : ptent = ptep_get_and_clear_full(mm, addr, pte,
499 0 : tlb->fullmm);
500 0 : ptent = pte_mkold(ptent);
501 0 : set_pte_at(mm, addr, pte, ptent);
502 : tlb_remove_tlb_entry(tlb, pte, addr);
503 : }
504 :
505 : /*
506 : * We are deactivating a folio for accelerating reclaiming.
507 : * VM couldn't reclaim the folio unless we clear PG_young.
508 : * As a side effect, it makes confuse idle-page tracking
509 : * because they will miss recent referenced history.
510 : */
511 0 : folio_clear_referenced(folio);
512 0 : folio_test_clear_young(folio);
513 0 : if (pageout) {
514 0 : if (folio_isolate_lru(folio)) {
515 0 : if (folio_test_unevictable(folio))
516 0 : folio_putback_lru(folio);
517 : else
518 0 : list_add(&folio->lru, &folio_list);
519 : }
520 : } else
521 0 : folio_deactivate(folio);
522 : }
523 :
524 0 : if (start_pte) {
525 : arch_leave_lazy_mmu_mode();
526 0 : pte_unmap_unlock(start_pte, ptl);
527 : }
528 0 : if (pageout)
529 0 : reclaim_pages(&folio_list);
530 0 : cond_resched();
531 :
532 0 : return 0;
533 : }
534 :
535 : static const struct mm_walk_ops cold_walk_ops = {
536 : .pmd_entry = madvise_cold_or_pageout_pte_range,
537 : };
538 :
539 0 : static void madvise_cold_page_range(struct mmu_gather *tlb,
540 : struct vm_area_struct *vma,
541 : unsigned long addr, unsigned long end)
542 : {
543 0 : struct madvise_walk_private walk_private = {
544 : .pageout = false,
545 : .tlb = tlb,
546 : };
547 :
548 0 : tlb_start_vma(tlb, vma);
549 0 : walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private);
550 0 : tlb_end_vma(tlb, vma);
551 0 : }
552 :
553 : static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
554 : {
555 0 : return !(vma->vm_flags & (VM_LOCKED|VM_PFNMAP|VM_HUGETLB));
556 : }
557 :
558 0 : static long madvise_cold(struct vm_area_struct *vma,
559 : struct vm_area_struct **prev,
560 : unsigned long start_addr, unsigned long end_addr)
561 : {
562 0 : struct mm_struct *mm = vma->vm_mm;
563 : struct mmu_gather tlb;
564 :
565 0 : *prev = vma;
566 0 : if (!can_madv_lru_vma(vma))
567 : return -EINVAL;
568 :
569 0 : lru_add_drain();
570 0 : tlb_gather_mmu(&tlb, mm);
571 0 : madvise_cold_page_range(&tlb, vma, start_addr, end_addr);
572 0 : tlb_finish_mmu(&tlb);
573 :
574 0 : return 0;
575 : }
576 :
577 0 : static void madvise_pageout_page_range(struct mmu_gather *tlb,
578 : struct vm_area_struct *vma,
579 : unsigned long addr, unsigned long end)
580 : {
581 0 : struct madvise_walk_private walk_private = {
582 : .pageout = true,
583 : .tlb = tlb,
584 : };
585 :
586 0 : tlb_start_vma(tlb, vma);
587 0 : walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private);
588 0 : tlb_end_vma(tlb, vma);
589 0 : }
590 :
591 0 : static long madvise_pageout(struct vm_area_struct *vma,
592 : struct vm_area_struct **prev,
593 : unsigned long start_addr, unsigned long end_addr)
594 : {
595 0 : struct mm_struct *mm = vma->vm_mm;
596 : struct mmu_gather tlb;
597 :
598 0 : *prev = vma;
599 0 : if (!can_madv_lru_vma(vma))
600 : return -EINVAL;
601 :
602 : /*
603 : * If the VMA belongs to a private file mapping, there can be private
604 : * dirty pages which can be paged out if even this process is neither
605 : * owner nor write capable of the file. We allow private file mappings
606 : * further to pageout dirty anon pages.
607 : */
608 0 : if (!vma_is_anonymous(vma) && (!can_do_file_pageout(vma) &&
609 0 : (vma->vm_flags & VM_MAYSHARE)))
610 : return 0;
611 :
612 0 : lru_add_drain();
613 0 : tlb_gather_mmu(&tlb, mm);
614 0 : madvise_pageout_page_range(&tlb, vma, start_addr, end_addr);
615 0 : tlb_finish_mmu(&tlb);
616 :
617 0 : return 0;
618 : }
619 :
620 0 : static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
621 : unsigned long end, struct mm_walk *walk)
622 :
623 : {
624 0 : struct mmu_gather *tlb = walk->private;
625 0 : struct mm_struct *mm = tlb->mm;
626 0 : struct vm_area_struct *vma = walk->vma;
627 : spinlock_t *ptl;
628 : pte_t *start_pte, *pte, ptent;
629 : struct folio *folio;
630 0 : int nr_swap = 0;
631 : unsigned long next;
632 :
633 0 : next = pmd_addr_end(addr, end);
634 0 : if (pmd_trans_huge(*pmd))
635 : if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next))
636 : return 0;
637 :
638 0 : tlb_change_page_size(tlb, PAGE_SIZE);
639 0 : start_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
640 0 : if (!start_pte)
641 : return 0;
642 : flush_tlb_batched_pending(mm);
643 : arch_enter_lazy_mmu_mode();
644 0 : for (; addr != end; pte++, addr += PAGE_SIZE) {
645 0 : ptent = ptep_get(pte);
646 :
647 0 : if (pte_none(ptent))
648 0 : continue;
649 : /*
650 : * If the pte has swp_entry, just clear page table to
651 : * prevent swap-in which is more expensive rather than
652 : * (page allocation + zeroing).
653 : */
654 0 : if (!pte_present(ptent)) {
655 : swp_entry_t entry;
656 :
657 0 : entry = pte_to_swp_entry(ptent);
658 0 : if (!non_swap_entry(entry)) {
659 0 : nr_swap--;
660 0 : free_swap_and_cache(entry);
661 0 : pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
662 0 : } else if (is_hwpoison_entry(entry) ||
663 0 : is_swapin_error_entry(entry)) {
664 0 : pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
665 : }
666 0 : continue;
667 : }
668 :
669 0 : folio = vm_normal_folio(vma, addr, ptent);
670 0 : if (!folio || folio_is_zone_device(folio))
671 0 : continue;
672 :
673 : /*
674 : * If pmd isn't transhuge but the folio is large and
675 : * is owned by only this process, split it and
676 : * deactivate all pages.
677 : */
678 0 : if (folio_test_large(folio)) {
679 : int err;
680 :
681 0 : if (folio_mapcount(folio) != 1)
682 : break;
683 0 : if (!folio_trylock(folio))
684 : break;
685 0 : folio_get(folio);
686 : arch_leave_lazy_mmu_mode();
687 0 : pte_unmap_unlock(start_pte, ptl);
688 0 : start_pte = NULL;
689 0 : err = split_folio(folio);
690 0 : folio_unlock(folio);
691 0 : folio_put(folio);
692 : if (err)
693 : break;
694 0 : start_pte = pte =
695 : pte_offset_map_lock(mm, pmd, addr, &ptl);
696 0 : if (!start_pte)
697 : break;
698 : arch_enter_lazy_mmu_mode();
699 0 : pte--;
700 0 : addr -= PAGE_SIZE;
701 0 : continue;
702 : }
703 :
704 0 : if (folio_test_swapcache(folio) || folio_test_dirty(folio)) {
705 0 : if (!folio_trylock(folio))
706 0 : continue;
707 : /*
708 : * If folio is shared with others, we mustn't clear
709 : * the folio's dirty flag.
710 : */
711 0 : if (folio_mapcount(folio) != 1) {
712 0 : folio_unlock(folio);
713 0 : continue;
714 : }
715 :
716 0 : if (folio_test_swapcache(folio) &&
717 0 : !folio_free_swap(folio)) {
718 0 : folio_unlock(folio);
719 0 : continue;
720 : }
721 :
722 0 : folio_clear_dirty(folio);
723 0 : folio_unlock(folio);
724 : }
725 :
726 0 : if (pte_young(ptent) || pte_dirty(ptent)) {
727 : /*
728 : * Some of architecture(ex, PPC) don't update TLB
729 : * with set_pte_at and tlb_remove_tlb_entry so for
730 : * the portability, remap the pte with old|clean
731 : * after pte clearing.
732 : */
733 0 : ptent = ptep_get_and_clear_full(mm, addr, pte,
734 0 : tlb->fullmm);
735 :
736 0 : ptent = pte_mkold(ptent);
737 0 : ptent = pte_mkclean(ptent);
738 0 : set_pte_at(mm, addr, pte, ptent);
739 : tlb_remove_tlb_entry(tlb, pte, addr);
740 : }
741 0 : folio_mark_lazyfree(folio);
742 : }
743 :
744 0 : if (nr_swap) {
745 0 : if (current->mm == mm)
746 : sync_mm_rss(mm);
747 0 : add_mm_counter(mm, MM_SWAPENTS, nr_swap);
748 : }
749 0 : if (start_pte) {
750 : arch_leave_lazy_mmu_mode();
751 0 : pte_unmap_unlock(start_pte, ptl);
752 : }
753 0 : cond_resched();
754 :
755 0 : return 0;
756 : }
757 :
758 : static const struct mm_walk_ops madvise_free_walk_ops = {
759 : .pmd_entry = madvise_free_pte_range,
760 : };
761 :
762 0 : static int madvise_free_single_vma(struct vm_area_struct *vma,
763 : unsigned long start_addr, unsigned long end_addr)
764 : {
765 0 : struct mm_struct *mm = vma->vm_mm;
766 : struct mmu_notifier_range range;
767 : struct mmu_gather tlb;
768 :
769 : /* MADV_FREE works for only anon vma at the moment */
770 0 : if (!vma_is_anonymous(vma))
771 : return -EINVAL;
772 :
773 0 : range.start = max(vma->vm_start, start_addr);
774 0 : if (range.start >= vma->vm_end)
775 : return -EINVAL;
776 0 : range.end = min(vma->vm_end, end_addr);
777 0 : if (range.end <= vma->vm_start)
778 : return -EINVAL;
779 0 : mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm,
780 : range.start, range.end);
781 :
782 0 : lru_add_drain();
783 0 : tlb_gather_mmu(&tlb, mm);
784 0 : update_hiwater_rss(mm);
785 :
786 0 : mmu_notifier_invalidate_range_start(&range);
787 0 : tlb_start_vma(&tlb, vma);
788 0 : walk_page_range(vma->vm_mm, range.start, range.end,
789 : &madvise_free_walk_ops, &tlb);
790 0 : tlb_end_vma(&tlb, vma);
791 0 : mmu_notifier_invalidate_range_end(&range);
792 0 : tlb_finish_mmu(&tlb);
793 :
794 0 : return 0;
795 : }
796 :
797 : /*
798 : * Application no longer needs these pages. If the pages are dirty,
799 : * it's OK to just throw them away. The app will be more careful about
800 : * data it wants to keep. Be sure to free swap resources too. The
801 : * zap_page_range_single call sets things up for shrink_active_list to actually
802 : * free these pages later if no one else has touched them in the meantime,
803 : * although we could add these pages to a global reuse list for
804 : * shrink_active_list to pick up before reclaiming other pages.
805 : *
806 : * NB: This interface discards data rather than pushes it out to swap,
807 : * as some implementations do. This has performance implications for
808 : * applications like large transactional databases which want to discard
809 : * pages in anonymous maps after committing to backing store the data
810 : * that was kept in them. There is no reason to write this data out to
811 : * the swap area if the application is discarding it.
812 : *
813 : * An interface that causes the system to free clean pages and flush
814 : * dirty pages is already available as msync(MS_INVALIDATE).
815 : */
816 : static long madvise_dontneed_single_vma(struct vm_area_struct *vma,
817 : unsigned long start, unsigned long end)
818 : {
819 0 : zap_page_range_single(vma, start, end - start, NULL);
820 : return 0;
821 : }
822 :
823 : static bool madvise_dontneed_free_valid_vma(struct vm_area_struct *vma,
824 : unsigned long start,
825 : unsigned long *end,
826 : int behavior)
827 : {
828 0 : if (!is_vm_hugetlb_page(vma)) {
829 0 : unsigned int forbidden = VM_PFNMAP;
830 :
831 0 : if (behavior != MADV_DONTNEED_LOCKED)
832 0 : forbidden |= VM_LOCKED;
833 :
834 0 : return !(vma->vm_flags & forbidden);
835 : }
836 :
837 : if (behavior != MADV_DONTNEED && behavior != MADV_DONTNEED_LOCKED)
838 : return false;
839 : if (start & ~huge_page_mask(hstate_vma(vma)))
840 : return false;
841 :
842 : /*
843 : * Madvise callers expect the length to be rounded up to PAGE_SIZE
844 : * boundaries, and may be unaware that this VMA uses huge pages.
845 : * Avoid unexpected data loss by rounding down the number of
846 : * huge pages freed.
847 : */
848 : *end = ALIGN_DOWN(*end, huge_page_size(hstate_vma(vma)));
849 :
850 : return true;
851 : }
852 :
853 0 : static long madvise_dontneed_free(struct vm_area_struct *vma,
854 : struct vm_area_struct **prev,
855 : unsigned long start, unsigned long end,
856 : int behavior)
857 : {
858 0 : struct mm_struct *mm = vma->vm_mm;
859 :
860 0 : *prev = vma;
861 0 : if (!madvise_dontneed_free_valid_vma(vma, start, &end, behavior))
862 : return -EINVAL;
863 :
864 0 : if (start == end)
865 : return 0;
866 :
867 0 : if (!userfaultfd_remove(vma, start, end)) {
868 : *prev = NULL; /* mmap_lock has been dropped, prev is stale */
869 :
870 : mmap_read_lock(mm);
871 : vma = vma_lookup(mm, start);
872 : if (!vma)
873 : return -ENOMEM;
874 : /*
875 : * Potential end adjustment for hugetlb vma is OK as
876 : * the check below keeps end within vma.
877 : */
878 : if (!madvise_dontneed_free_valid_vma(vma, start, &end,
879 : behavior))
880 : return -EINVAL;
881 : if (end > vma->vm_end) {
882 : /*
883 : * Don't fail if end > vma->vm_end. If the old
884 : * vma was split while the mmap_lock was
885 : * released the effect of the concurrent
886 : * operation may not cause madvise() to
887 : * have an undefined result. There may be an
888 : * adjacent next vma that we'll walk
889 : * next. userfaultfd_remove() will generate an
890 : * UFFD_EVENT_REMOVE repetition on the
891 : * end-vma->vm_end range, but the manager can
892 : * handle a repetition fine.
893 : */
894 : end = vma->vm_end;
895 : }
896 : VM_WARN_ON(start >= end);
897 : }
898 :
899 0 : if (behavior == MADV_DONTNEED || behavior == MADV_DONTNEED_LOCKED)
900 0 : return madvise_dontneed_single_vma(vma, start, end);
901 0 : else if (behavior == MADV_FREE)
902 0 : return madvise_free_single_vma(vma, start, end);
903 : else
904 : return -EINVAL;
905 : }
906 :
907 0 : static long madvise_populate(struct vm_area_struct *vma,
908 : struct vm_area_struct **prev,
909 : unsigned long start, unsigned long end,
910 : int behavior)
911 : {
912 0 : const bool write = behavior == MADV_POPULATE_WRITE;
913 0 : struct mm_struct *mm = vma->vm_mm;
914 : unsigned long tmp_end;
915 0 : int locked = 1;
916 : long pages;
917 :
918 0 : *prev = vma;
919 :
920 0 : while (start < end) {
921 : /*
922 : * We might have temporarily dropped the lock. For example,
923 : * our VMA might have been split.
924 : */
925 0 : if (!vma || start >= vma->vm_end) {
926 0 : vma = vma_lookup(mm, start);
927 0 : if (!vma)
928 : return -ENOMEM;
929 : }
930 :
931 0 : tmp_end = min_t(unsigned long, end, vma->vm_end);
932 : /* Populate (prefault) page tables readable/writable. */
933 0 : pages = faultin_vma_page_range(vma, start, tmp_end, write,
934 : &locked);
935 0 : if (!locked) {
936 0 : mmap_read_lock(mm);
937 0 : locked = 1;
938 0 : *prev = NULL;
939 0 : vma = NULL;
940 : }
941 0 : if (pages < 0) {
942 0 : switch (pages) {
943 : case -EINTR:
944 : return -EINTR;
945 : case -EINVAL: /* Incompatible mappings / permissions. */
946 0 : return -EINVAL;
947 : case -EHWPOISON:
948 0 : return -EHWPOISON;
949 : case -EFAULT: /* VM_FAULT_SIGBUS or VM_FAULT_SIGSEGV */
950 0 : return -EFAULT;
951 : default:
952 0 : pr_warn_once("%s: unhandled return value: %ld\n",
953 : __func__, pages);
954 : fallthrough;
955 : case -ENOMEM:
956 : return -ENOMEM;
957 : }
958 : }
959 0 : start += pages * PAGE_SIZE;
960 : }
961 : return 0;
962 : }
963 :
964 : /*
965 : * Application wants to free up the pages and associated backing store.
966 : * This is effectively punching a hole into the middle of a file.
967 : */
968 0 : static long madvise_remove(struct vm_area_struct *vma,
969 : struct vm_area_struct **prev,
970 : unsigned long start, unsigned long end)
971 : {
972 : loff_t offset;
973 : int error;
974 : struct file *f;
975 0 : struct mm_struct *mm = vma->vm_mm;
976 :
977 0 : *prev = NULL; /* tell sys_madvise we drop mmap_lock */
978 :
979 0 : if (vma->vm_flags & VM_LOCKED)
980 : return -EINVAL;
981 :
982 0 : f = vma->vm_file;
983 :
984 0 : if (!f || !f->f_mapping || !f->f_mapping->host) {
985 : return -EINVAL;
986 : }
987 :
988 0 : if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
989 : return -EACCES;
990 :
991 0 : offset = (loff_t)(start - vma->vm_start)
992 0 : + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
993 :
994 : /*
995 : * Filesystem's fallocate may need to take i_rwsem. We need to
996 : * explicitly grab a reference because the vma (and hence the
997 : * vma's reference to the file) can go away as soon as we drop
998 : * mmap_lock.
999 : */
1000 0 : get_file(f);
1001 0 : if (userfaultfd_remove(vma, start, end)) {
1002 : /* mmap_lock was not released by userfaultfd_remove() */
1003 : mmap_read_unlock(mm);
1004 : }
1005 0 : error = vfs_fallocate(f,
1006 : FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
1007 0 : offset, end - start);
1008 0 : fput(f);
1009 0 : mmap_read_lock(mm);
1010 0 : return error;
1011 : }
1012 :
1013 : /*
1014 : * Apply an madvise behavior to a region of a vma. madvise_update_vma
1015 : * will handle splitting a vm area into separate areas, each area with its own
1016 : * behavior.
1017 : */
1018 0 : static int madvise_vma_behavior(struct vm_area_struct *vma,
1019 : struct vm_area_struct **prev,
1020 : unsigned long start, unsigned long end,
1021 : unsigned long behavior)
1022 : {
1023 : int error;
1024 : struct anon_vma_name *anon_name;
1025 0 : unsigned long new_flags = vma->vm_flags;
1026 :
1027 0 : switch (behavior) {
1028 : case MADV_REMOVE:
1029 0 : return madvise_remove(vma, prev, start, end);
1030 : case MADV_WILLNEED:
1031 0 : return madvise_willneed(vma, prev, start, end);
1032 : case MADV_COLD:
1033 0 : return madvise_cold(vma, prev, start, end);
1034 : case MADV_PAGEOUT:
1035 0 : return madvise_pageout(vma, prev, start, end);
1036 : case MADV_FREE:
1037 : case MADV_DONTNEED:
1038 : case MADV_DONTNEED_LOCKED:
1039 0 : return madvise_dontneed_free(vma, prev, start, end, behavior);
1040 : case MADV_POPULATE_READ:
1041 : case MADV_POPULATE_WRITE:
1042 0 : return madvise_populate(vma, prev, start, end, behavior);
1043 : case MADV_NORMAL:
1044 0 : new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
1045 0 : break;
1046 : case MADV_SEQUENTIAL:
1047 0 : new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
1048 0 : break;
1049 : case MADV_RANDOM:
1050 0 : new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
1051 0 : break;
1052 : case MADV_DONTFORK:
1053 0 : new_flags |= VM_DONTCOPY;
1054 0 : break;
1055 : case MADV_DOFORK:
1056 0 : if (vma->vm_flags & VM_IO)
1057 : return -EINVAL;
1058 0 : new_flags &= ~VM_DONTCOPY;
1059 0 : break;
1060 : case MADV_WIPEONFORK:
1061 : /* MADV_WIPEONFORK is only supported on anonymous memory. */
1062 0 : if (vma->vm_file || vma->vm_flags & VM_SHARED)
1063 : return -EINVAL;
1064 0 : new_flags |= VM_WIPEONFORK;
1065 0 : break;
1066 : case MADV_KEEPONFORK:
1067 0 : new_flags &= ~VM_WIPEONFORK;
1068 0 : break;
1069 : case MADV_DONTDUMP:
1070 0 : new_flags |= VM_DONTDUMP;
1071 0 : break;
1072 : case MADV_DODUMP:
1073 0 : if (!is_vm_hugetlb_page(vma) && new_flags & VM_SPECIAL)
1074 : return -EINVAL;
1075 0 : new_flags &= ~VM_DONTDUMP;
1076 0 : break;
1077 : case MADV_MERGEABLE:
1078 : case MADV_UNMERGEABLE:
1079 : error = ksm_madvise(vma, start, end, behavior, &new_flags);
1080 : if (error)
1081 : goto out;
1082 : break;
1083 : case MADV_HUGEPAGE:
1084 : case MADV_NOHUGEPAGE:
1085 : error = hugepage_madvise(vma, &new_flags, behavior);
1086 : if (error)
1087 : goto out;
1088 : break;
1089 : case MADV_COLLAPSE:
1090 : return madvise_collapse(vma, prev, start, end);
1091 : }
1092 :
1093 0 : anon_name = anon_vma_name(vma);
1094 : anon_vma_name_get(anon_name);
1095 0 : error = madvise_update_vma(vma, prev, start, end, new_flags,
1096 : anon_name);
1097 : anon_vma_name_put(anon_name);
1098 :
1099 : out:
1100 : /*
1101 : * madvise() returns EAGAIN if kernel resources, such as
1102 : * slab, are temporarily unavailable.
1103 : */
1104 0 : if (error == -ENOMEM)
1105 0 : error = -EAGAIN;
1106 : return error;
1107 : }
1108 :
1109 : #ifdef CONFIG_MEMORY_FAILURE
1110 : /*
1111 : * Error injection support for memory error handling.
1112 : */
1113 : static int madvise_inject_error(int behavior,
1114 : unsigned long start, unsigned long end)
1115 : {
1116 : unsigned long size;
1117 :
1118 : if (!capable(CAP_SYS_ADMIN))
1119 : return -EPERM;
1120 :
1121 :
1122 : for (; start < end; start += size) {
1123 : unsigned long pfn;
1124 : struct page *page;
1125 : int ret;
1126 :
1127 : ret = get_user_pages_fast(start, 1, 0, &page);
1128 : if (ret != 1)
1129 : return ret;
1130 : pfn = page_to_pfn(page);
1131 :
1132 : /*
1133 : * When soft offlining hugepages, after migrating the page
1134 : * we dissolve it, therefore in the second loop "page" will
1135 : * no longer be a compound page.
1136 : */
1137 : size = page_size(compound_head(page));
1138 :
1139 : if (behavior == MADV_SOFT_OFFLINE) {
1140 : pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
1141 : pfn, start);
1142 : ret = soft_offline_page(pfn, MF_COUNT_INCREASED);
1143 : } else {
1144 : pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
1145 : pfn, start);
1146 : ret = memory_failure(pfn, MF_COUNT_INCREASED | MF_SW_SIMULATED);
1147 : if (ret == -EOPNOTSUPP)
1148 : ret = 0;
1149 : }
1150 :
1151 : if (ret)
1152 : return ret;
1153 : }
1154 :
1155 : return 0;
1156 : }
1157 : #endif
1158 :
1159 : static bool
1160 : madvise_behavior_valid(int behavior)
1161 : {
1162 : switch (behavior) {
1163 : case MADV_DOFORK:
1164 : case MADV_DONTFORK:
1165 : case MADV_NORMAL:
1166 : case MADV_SEQUENTIAL:
1167 : case MADV_RANDOM:
1168 : case MADV_REMOVE:
1169 : case MADV_WILLNEED:
1170 : case MADV_DONTNEED:
1171 : case MADV_DONTNEED_LOCKED:
1172 : case MADV_FREE:
1173 : case MADV_COLD:
1174 : case MADV_PAGEOUT:
1175 : case MADV_POPULATE_READ:
1176 : case MADV_POPULATE_WRITE:
1177 : #ifdef CONFIG_KSM
1178 : case MADV_MERGEABLE:
1179 : case MADV_UNMERGEABLE:
1180 : #endif
1181 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1182 : case MADV_HUGEPAGE:
1183 : case MADV_NOHUGEPAGE:
1184 : case MADV_COLLAPSE:
1185 : #endif
1186 : case MADV_DONTDUMP:
1187 : case MADV_DODUMP:
1188 : case MADV_WIPEONFORK:
1189 : case MADV_KEEPONFORK:
1190 : #ifdef CONFIG_MEMORY_FAILURE
1191 : case MADV_SOFT_OFFLINE:
1192 : case MADV_HWPOISON:
1193 : #endif
1194 : return true;
1195 :
1196 : default:
1197 : return false;
1198 : }
1199 : }
1200 :
1201 : static bool process_madvise_behavior_valid(int behavior)
1202 : {
1203 : switch (behavior) {
1204 : case MADV_COLD:
1205 : case MADV_PAGEOUT:
1206 : case MADV_WILLNEED:
1207 : case MADV_COLLAPSE:
1208 : return true;
1209 : default:
1210 : return false;
1211 : }
1212 : }
1213 :
1214 : /*
1215 : * Walk the vmas in range [start,end), and call the visit function on each one.
1216 : * The visit function will get start and end parameters that cover the overlap
1217 : * between the current vma and the original range. Any unmapped regions in the
1218 : * original range will result in this function returning -ENOMEM while still
1219 : * calling the visit function on all of the existing vmas in the range.
1220 : * Must be called with the mmap_lock held for reading or writing.
1221 : */
1222 : static
1223 0 : int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
1224 : unsigned long end, unsigned long arg,
1225 : int (*visit)(struct vm_area_struct *vma,
1226 : struct vm_area_struct **prev, unsigned long start,
1227 : unsigned long end, unsigned long arg))
1228 : {
1229 : struct vm_area_struct *vma;
1230 : struct vm_area_struct *prev;
1231 : unsigned long tmp;
1232 0 : int unmapped_error = 0;
1233 :
1234 : /*
1235 : * If the interval [start,end) covers some unmapped address
1236 : * ranges, just ignore them, but return -ENOMEM at the end.
1237 : * - different from the way of handling in mlock etc.
1238 : */
1239 0 : vma = find_vma_prev(mm, start, &prev);
1240 0 : if (vma && start > vma->vm_start)
1241 0 : prev = vma;
1242 :
1243 : for (;;) {
1244 : int error;
1245 :
1246 : /* Still start < end. */
1247 0 : if (!vma)
1248 : return -ENOMEM;
1249 :
1250 : /* Here start < (end|vma->vm_end). */
1251 0 : if (start < vma->vm_start) {
1252 0 : unmapped_error = -ENOMEM;
1253 0 : start = vma->vm_start;
1254 0 : if (start >= end)
1255 : break;
1256 : }
1257 :
1258 : /* Here vma->vm_start <= start < (end|vma->vm_end) */
1259 0 : tmp = vma->vm_end;
1260 0 : if (end < tmp)
1261 0 : tmp = end;
1262 :
1263 : /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
1264 0 : error = visit(vma, &prev, start, tmp, arg);
1265 0 : if (error)
1266 : return error;
1267 0 : start = tmp;
1268 0 : if (prev && start < prev->vm_end)
1269 0 : start = prev->vm_end;
1270 0 : if (start >= end)
1271 : break;
1272 0 : if (prev)
1273 0 : vma = find_vma(mm, prev->vm_end);
1274 : else /* madvise_remove dropped mmap_lock */
1275 0 : vma = find_vma(mm, start);
1276 : }
1277 :
1278 : return unmapped_error;
1279 : }
1280 :
1281 : #ifdef CONFIG_ANON_VMA_NAME
1282 : static int madvise_vma_anon_name(struct vm_area_struct *vma,
1283 : struct vm_area_struct **prev,
1284 : unsigned long start, unsigned long end,
1285 : unsigned long anon_name)
1286 : {
1287 : int error;
1288 :
1289 : /* Only anonymous mappings can be named */
1290 : if (vma->vm_file && !vma_is_anon_shmem(vma))
1291 : return -EBADF;
1292 :
1293 : error = madvise_update_vma(vma, prev, start, end, vma->vm_flags,
1294 : (struct anon_vma_name *)anon_name);
1295 :
1296 : /*
1297 : * madvise() returns EAGAIN if kernel resources, such as
1298 : * slab, are temporarily unavailable.
1299 : */
1300 : if (error == -ENOMEM)
1301 : error = -EAGAIN;
1302 : return error;
1303 : }
1304 :
1305 : int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
1306 : unsigned long len_in, struct anon_vma_name *anon_name)
1307 : {
1308 : unsigned long end;
1309 : unsigned long len;
1310 :
1311 : if (start & ~PAGE_MASK)
1312 : return -EINVAL;
1313 : len = (len_in + ~PAGE_MASK) & PAGE_MASK;
1314 :
1315 : /* Check to see whether len was rounded up from small -ve to zero */
1316 : if (len_in && !len)
1317 : return -EINVAL;
1318 :
1319 : end = start + len;
1320 : if (end < start)
1321 : return -EINVAL;
1322 :
1323 : if (end == start)
1324 : return 0;
1325 :
1326 : return madvise_walk_vmas(mm, start, end, (unsigned long)anon_name,
1327 : madvise_vma_anon_name);
1328 : }
1329 : #endif /* CONFIG_ANON_VMA_NAME */
1330 : /*
1331 : * The madvise(2) system call.
1332 : *
1333 : * Applications can use madvise() to advise the kernel how it should
1334 : * handle paging I/O in this VM area. The idea is to help the kernel
1335 : * use appropriate read-ahead and caching techniques. The information
1336 : * provided is advisory only, and can be safely disregarded by the
1337 : * kernel without affecting the correct operation of the application.
1338 : *
1339 : * behavior values:
1340 : * MADV_NORMAL - the default behavior is to read clusters. This
1341 : * results in some read-ahead and read-behind.
1342 : * MADV_RANDOM - the system should read the minimum amount of data
1343 : * on any access, since it is unlikely that the appli-
1344 : * cation will need more than what it asks for.
1345 : * MADV_SEQUENTIAL - pages in the given range will probably be accessed
1346 : * once, so they can be aggressively read ahead, and
1347 : * can be freed soon after they are accessed.
1348 : * MADV_WILLNEED - the application is notifying the system to read
1349 : * some pages ahead.
1350 : * MADV_DONTNEED - the application is finished with the given range,
1351 : * so the kernel can free resources associated with it.
1352 : * MADV_FREE - the application marks pages in the given range as lazy free,
1353 : * where actual purges are postponed until memory pressure happens.
1354 : * MADV_REMOVE - the application wants to free up the given range of
1355 : * pages and associated backing store.
1356 : * MADV_DONTFORK - omit this area from child's address space when forking:
1357 : * typically, to avoid COWing pages pinned by get_user_pages().
1358 : * MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
1359 : * MADV_WIPEONFORK - present the child process with zero-filled memory in this
1360 : * range after a fork.
1361 : * MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK
1362 : * MADV_HWPOISON - trigger memory error handler as if the given memory range
1363 : * were corrupted by unrecoverable hardware memory failure.
1364 : * MADV_SOFT_OFFLINE - try to soft-offline the given range of memory.
1365 : * MADV_MERGEABLE - the application recommends that KSM try to merge pages in
1366 : * this area with pages of identical content from other such areas.
1367 : * MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
1368 : * MADV_HUGEPAGE - the application wants to back the given range by transparent
1369 : * huge pages in the future. Existing pages might be coalesced and
1370 : * new pages might be allocated as THP.
1371 : * MADV_NOHUGEPAGE - mark the given range as not worth being backed by
1372 : * transparent huge pages so the existing pages will not be
1373 : * coalesced into THP and new pages will not be allocated as THP.
1374 : * MADV_COLLAPSE - synchronously coalesce pages into new THP.
1375 : * MADV_DONTDUMP - the application wants to prevent pages in the given range
1376 : * from being included in its core dump.
1377 : * MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
1378 : * MADV_COLD - the application is not expected to use this memory soon,
1379 : * deactivate pages in this range so that they can be reclaimed
1380 : * easily if memory pressure happens.
1381 : * MADV_PAGEOUT - the application is not expected to use this memory soon,
1382 : * page out the pages in this range immediately.
1383 : * MADV_POPULATE_READ - populate (prefault) page tables readable by
1384 : * triggering read faults if required
1385 : * MADV_POPULATE_WRITE - populate (prefault) page tables writable by
1386 : * triggering write faults if required
1387 : *
1388 : * return values:
1389 : * zero - success
1390 : * -EINVAL - start + len < 0, start is not page-aligned,
1391 : * "behavior" is not a valid value, or application
1392 : * is attempting to release locked or shared pages,
1393 : * or the specified address range includes file, Huge TLB,
1394 : * MAP_SHARED or VMPFNMAP range.
1395 : * -ENOMEM - addresses in the specified range are not currently
1396 : * mapped, or are outside the AS of the process.
1397 : * -EIO - an I/O error occurred while paging in data.
1398 : * -EBADF - map exists, but area maps something that isn't a file.
1399 : * -EAGAIN - a kernel resource was temporarily unavailable.
1400 : */
1401 0 : int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior)
1402 : {
1403 : unsigned long end;
1404 : int error;
1405 : int write;
1406 : size_t len;
1407 : struct blk_plug plug;
1408 :
1409 0 : if (!madvise_behavior_valid(behavior))
1410 : return -EINVAL;
1411 :
1412 0 : if (!PAGE_ALIGNED(start))
1413 : return -EINVAL;
1414 0 : len = PAGE_ALIGN(len_in);
1415 :
1416 : /* Check to see whether len was rounded up from small -ve to zero */
1417 0 : if (len_in && !len)
1418 : return -EINVAL;
1419 :
1420 0 : end = start + len;
1421 0 : if (end < start)
1422 : return -EINVAL;
1423 :
1424 0 : if (end == start)
1425 : return 0;
1426 :
1427 : #ifdef CONFIG_MEMORY_FAILURE
1428 : if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
1429 : return madvise_inject_error(behavior, start, start + len_in);
1430 : #endif
1431 :
1432 0 : write = madvise_need_mmap_write(behavior);
1433 0 : if (write) {
1434 0 : if (mmap_write_lock_killable(mm))
1435 : return -EINTR;
1436 : } else {
1437 : mmap_read_lock(mm);
1438 : }
1439 :
1440 0 : start = untagged_addr_remote(mm, start);
1441 0 : end = start + len;
1442 :
1443 0 : blk_start_plug(&plug);
1444 0 : error = madvise_walk_vmas(mm, start, end, behavior,
1445 : madvise_vma_behavior);
1446 0 : blk_finish_plug(&plug);
1447 0 : if (write)
1448 : mmap_write_unlock(mm);
1449 : else
1450 : mmap_read_unlock(mm);
1451 :
1452 : return error;
1453 : }
1454 :
1455 0 : SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
1456 : {
1457 0 : return do_madvise(current->mm, start, len_in, behavior);
1458 : }
1459 :
1460 0 : SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
1461 : size_t, vlen, int, behavior, unsigned int, flags)
1462 : {
1463 : ssize_t ret;
1464 : struct iovec iovstack[UIO_FASTIOV];
1465 0 : struct iovec *iov = iovstack;
1466 : struct iov_iter iter;
1467 : struct task_struct *task;
1468 : struct mm_struct *mm;
1469 : size_t total_len;
1470 : unsigned int f_flags;
1471 :
1472 0 : if (flags != 0) {
1473 : ret = -EINVAL;
1474 : goto out;
1475 : }
1476 :
1477 0 : ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
1478 0 : if (ret < 0)
1479 : goto out;
1480 :
1481 0 : task = pidfd_get_task(pidfd, &f_flags);
1482 0 : if (IS_ERR(task)) {
1483 0 : ret = PTR_ERR(task);
1484 0 : goto free_iov;
1485 : }
1486 :
1487 0 : if (!process_madvise_behavior_valid(behavior)) {
1488 : ret = -EINVAL;
1489 : goto release_task;
1490 : }
1491 :
1492 : /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */
1493 0 : mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1494 0 : if (IS_ERR_OR_NULL(mm)) {
1495 0 : ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
1496 : goto release_task;
1497 : }
1498 :
1499 : /*
1500 : * Require CAP_SYS_NICE for influencing process performance. Note that
1501 : * only non-destructive hints are currently supported.
1502 : */
1503 0 : if (!capable(CAP_SYS_NICE)) {
1504 : ret = -EPERM;
1505 : goto release_mm;
1506 : }
1507 :
1508 0 : total_len = iov_iter_count(&iter);
1509 :
1510 0 : while (iov_iter_count(&iter)) {
1511 0 : ret = do_madvise(mm, (unsigned long)iter_iov_addr(&iter),
1512 0 : iter_iov_len(&iter), behavior);
1513 0 : if (ret < 0)
1514 : break;
1515 0 : iov_iter_advance(&iter, iter_iov_len(&iter));
1516 : }
1517 :
1518 0 : ret = (total_len - iov_iter_count(&iter)) ? : ret;
1519 :
1520 : release_mm:
1521 0 : mmput(mm);
1522 : release_task:
1523 0 : put_task_struct(task);
1524 : free_iov:
1525 0 : kfree(iov);
1526 : out:
1527 0 : return ret;
1528 : }
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