arm64: dts: imx8mm: Drop deprecated regulator-compatible from Variscite VAR-SOM-MX8MM
[linux-2.6-microblaze.git] / mm / madvise.c
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         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_sem 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 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         struct mm_struct *mm = vma->vm_mm;
143         int error;
144         pgoff_t pgoff;
145
146         if (new_flags == vma->vm_flags && anon_vma_name_eq(anon_vma_name(vma), anon_name)) {
147                 *prev = vma;
148                 return 0;
149         }
150
151         pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
152         *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
153                           vma->vm_file, pgoff, vma_policy(vma),
154                           vma->vm_userfaultfd_ctx, anon_name);
155         if (*prev) {
156                 vma = *prev;
157                 goto success;
158         }
159
160         *prev = vma;
161
162         if (start != vma->vm_start) {
163                 if (unlikely(mm->map_count >= sysctl_max_map_count))
164                         return -ENOMEM;
165                 error = __split_vma(mm, vma, start, 1);
166                 if (error)
167                         return error;
168         }
169
170         if (end != vma->vm_end) {
171                 if (unlikely(mm->map_count >= sysctl_max_map_count))
172                         return -ENOMEM;
173                 error = __split_vma(mm, vma, end, 0);
174                 if (error)
175                         return error;
176         }
177
178 success:
179         /*
180          * vm_flags is protected by the mmap_lock held in write mode.
181          */
182         vma->vm_flags = new_flags;
183         if (!vma->vm_file || vma_is_anon_shmem(vma)) {
184                 error = replace_anon_vma_name(vma, anon_name);
185                 if (error)
186                         return error;
187         }
188
189         return 0;
190 }
191
192 #ifdef CONFIG_SWAP
193 static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
194         unsigned long end, struct mm_walk *walk)
195 {
196         struct vm_area_struct *vma = walk->private;
197         unsigned long index;
198         struct swap_iocb *splug = NULL;
199
200         if (pmd_none_or_trans_huge_or_clear_bad(pmd))
201                 return 0;
202
203         for (index = start; index != end; index += PAGE_SIZE) {
204                 pte_t pte;
205                 swp_entry_t entry;
206                 struct page *page;
207                 spinlock_t *ptl;
208                 pte_t *ptep;
209
210                 ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
211                 pte = *ptep;
212                 pte_unmap_unlock(ptep, ptl);
213
214                 if (!is_swap_pte(pte))
215                         continue;
216                 entry = pte_to_swp_entry(pte);
217                 if (unlikely(non_swap_entry(entry)))
218                         continue;
219
220                 page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE,
221                                              vma, index, false, &splug);
222                 if (page)
223                         put_page(page);
224         }
225         swap_read_unplug(splug);
226         cond_resched();
227
228         return 0;
229 }
230
231 static const struct mm_walk_ops swapin_walk_ops = {
232         .pmd_entry              = swapin_walk_pmd_entry,
233 };
234
235 static void force_shm_swapin_readahead(struct vm_area_struct *vma,
236                 unsigned long start, unsigned long end,
237                 struct address_space *mapping)
238 {
239         XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start));
240         pgoff_t end_index = linear_page_index(vma, end + PAGE_SIZE - 1);
241         struct page *page;
242         struct swap_iocb *splug = NULL;
243
244         rcu_read_lock();
245         xas_for_each(&xas, page, end_index) {
246                 swp_entry_t swap;
247
248                 if (!xa_is_value(page))
249                         continue;
250                 swap = radix_to_swp_entry(page);
251                 /* There might be swapin error entries in shmem mapping. */
252                 if (non_swap_entry(swap))
253                         continue;
254                 xas_pause(&xas);
255                 rcu_read_unlock();
256
257                 page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE,
258                                              NULL, 0, false, &splug);
259                 if (page)
260                         put_page(page);
261
262                 rcu_read_lock();
263         }
264         rcu_read_unlock();
265         swap_read_unplug(splug);
266
267         lru_add_drain();        /* Push any new pages onto the LRU now */
268 }
269 #endif          /* CONFIG_SWAP */
270
271 /*
272  * Schedule all required I/O operations.  Do not wait for completion.
273  */
274 static long madvise_willneed(struct vm_area_struct *vma,
275                              struct vm_area_struct **prev,
276                              unsigned long start, unsigned long end)
277 {
278         struct mm_struct *mm = vma->vm_mm;
279         struct file *file = vma->vm_file;
280         loff_t offset;
281
282         *prev = vma;
283 #ifdef CONFIG_SWAP
284         if (!file) {
285                 walk_page_range(vma->vm_mm, start, end, &swapin_walk_ops, vma);
286                 lru_add_drain(); /* Push any new pages onto the LRU now */
287                 return 0;
288         }
289
290         if (shmem_mapping(file->f_mapping)) {
291                 force_shm_swapin_readahead(vma, start, end,
292                                         file->f_mapping);
293                 return 0;
294         }
295 #else
296         if (!file)
297                 return -EBADF;
298 #endif
299
300         if (IS_DAX(file_inode(file))) {
301                 /* no bad return value, but ignore advice */
302                 return 0;
303         }
304
305         /*
306          * Filesystem's fadvise may need to take various locks.  We need to
307          * explicitly grab a reference because the vma (and hence the
308          * vma's reference to the file) can go away as soon as we drop
309          * mmap_lock.
310          */
311         *prev = NULL;   /* tell sys_madvise we drop mmap_lock */
312         get_file(file);
313         offset = (loff_t)(start - vma->vm_start)
314                         + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
315         mmap_read_unlock(mm);
316         vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED);
317         fput(file);
318         mmap_read_lock(mm);
319         return 0;
320 }
321
322 static inline bool can_do_file_pageout(struct vm_area_struct *vma)
323 {
324         if (!vma->vm_file)
325                 return false;
326         /*
327          * paging out pagecache only for non-anonymous mappings that correspond
328          * to the files the calling process could (if tried) open for writing;
329          * otherwise we'd be including shared non-exclusive mappings, which
330          * opens a side channel.
331          */
332         return inode_owner_or_capable(&init_user_ns,
333                                       file_inode(vma->vm_file)) ||
334                file_permission(vma->vm_file, MAY_WRITE) == 0;
335 }
336
337 static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
338                                 unsigned long addr, unsigned long end,
339                                 struct mm_walk *walk)
340 {
341         struct madvise_walk_private *private = walk->private;
342         struct mmu_gather *tlb = private->tlb;
343         bool pageout = private->pageout;
344         struct mm_struct *mm = tlb->mm;
345         struct vm_area_struct *vma = walk->vma;
346         pte_t *orig_pte, *pte, ptent;
347         spinlock_t *ptl;
348         struct page *page = NULL;
349         LIST_HEAD(page_list);
350         bool pageout_anon_only_filter;
351
352         if (fatal_signal_pending(current))
353                 return -EINTR;
354
355         pageout_anon_only_filter = pageout && !vma_is_anonymous(vma) &&
356                                         !can_do_file_pageout(vma);
357
358 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
359         if (pmd_trans_huge(*pmd)) {
360                 pmd_t orig_pmd;
361                 unsigned long next = pmd_addr_end(addr, end);
362
363                 tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
364                 ptl = pmd_trans_huge_lock(pmd, vma);
365                 if (!ptl)
366                         return 0;
367
368                 orig_pmd = *pmd;
369                 if (is_huge_zero_pmd(orig_pmd))
370                         goto huge_unlock;
371
372                 if (unlikely(!pmd_present(orig_pmd))) {
373                         VM_BUG_ON(thp_migration_supported() &&
374                                         !is_pmd_migration_entry(orig_pmd));
375                         goto huge_unlock;
376                 }
377
378                 page = pmd_page(orig_pmd);
379
380                 /* Do not interfere with other mappings of this page */
381                 if (page_mapcount(page) != 1)
382                         goto huge_unlock;
383
384                 if (pageout_anon_only_filter && !PageAnon(page))
385                         goto huge_unlock;
386
387                 if (next - addr != HPAGE_PMD_SIZE) {
388                         int err;
389
390                         get_page(page);
391                         spin_unlock(ptl);
392                         lock_page(page);
393                         err = split_huge_page(page);
394                         unlock_page(page);
395                         put_page(page);
396                         if (!err)
397                                 goto regular_page;
398                         return 0;
399                 }
400
401                 if (pmd_young(orig_pmd)) {
402                         pmdp_invalidate(vma, addr, pmd);
403                         orig_pmd = pmd_mkold(orig_pmd);
404
405                         set_pmd_at(mm, addr, pmd, orig_pmd);
406                         tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
407                 }
408
409                 ClearPageReferenced(page);
410                 test_and_clear_page_young(page);
411                 if (pageout) {
412                         if (!isolate_lru_page(page)) {
413                                 if (PageUnevictable(page))
414                                         putback_lru_page(page);
415                                 else
416                                         list_add(&page->lru, &page_list);
417                         }
418                 } else
419                         deactivate_page(page);
420 huge_unlock:
421                 spin_unlock(ptl);
422                 if (pageout)
423                         reclaim_pages(&page_list);
424                 return 0;
425         }
426
427 regular_page:
428         if (pmd_trans_unstable(pmd))
429                 return 0;
430 #endif
431         tlb_change_page_size(tlb, PAGE_SIZE);
432         orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
433         flush_tlb_batched_pending(mm);
434         arch_enter_lazy_mmu_mode();
435         for (; addr < end; pte++, addr += PAGE_SIZE) {
436                 ptent = *pte;
437
438                 if (pte_none(ptent))
439                         continue;
440
441                 if (!pte_present(ptent))
442                         continue;
443
444                 page = vm_normal_page(vma, addr, ptent);
445                 if (!page || is_zone_device_page(page))
446                         continue;
447
448                 /*
449                  * Creating a THP page is expensive so split it only if we
450                  * are sure it's worth. Split it if we are only owner.
451                  */
452                 if (PageTransCompound(page)) {
453                         if (page_mapcount(page) != 1)
454                                 break;
455                         if (pageout_anon_only_filter && !PageAnon(page))
456                                 break;
457                         get_page(page);
458                         if (!trylock_page(page)) {
459                                 put_page(page);
460                                 break;
461                         }
462                         pte_unmap_unlock(orig_pte, ptl);
463                         if (split_huge_page(page)) {
464                                 unlock_page(page);
465                                 put_page(page);
466                                 orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
467                                 break;
468                         }
469                         unlock_page(page);
470                         put_page(page);
471                         orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
472                         pte--;
473                         addr -= PAGE_SIZE;
474                         continue;
475                 }
476
477                 /*
478                  * Do not interfere with other mappings of this page and
479                  * non-LRU page.
480                  */
481                 if (!PageLRU(page) || page_mapcount(page) != 1)
482                         continue;
483
484                 if (pageout_anon_only_filter && !PageAnon(page))
485                         continue;
486
487                 VM_BUG_ON_PAGE(PageTransCompound(page), page);
488
489                 if (pte_young(ptent)) {
490                         ptent = ptep_get_and_clear_full(mm, addr, pte,
491                                                         tlb->fullmm);
492                         ptent = pte_mkold(ptent);
493                         set_pte_at(mm, addr, pte, ptent);
494                         tlb_remove_tlb_entry(tlb, pte, addr);
495                 }
496
497                 /*
498                  * We are deactivating a page for accelerating reclaiming.
499                  * VM couldn't reclaim the page unless we clear PG_young.
500                  * As a side effect, it makes confuse idle-page tracking
501                  * because they will miss recent referenced history.
502                  */
503                 ClearPageReferenced(page);
504                 test_and_clear_page_young(page);
505                 if (pageout) {
506                         if (!isolate_lru_page(page)) {
507                                 if (PageUnevictable(page))
508                                         putback_lru_page(page);
509                                 else
510                                         list_add(&page->lru, &page_list);
511                         }
512                 } else
513                         deactivate_page(page);
514         }
515
516         arch_leave_lazy_mmu_mode();
517         pte_unmap_unlock(orig_pte, ptl);
518         if (pageout)
519                 reclaim_pages(&page_list);
520         cond_resched();
521
522         return 0;
523 }
524
525 static const struct mm_walk_ops cold_walk_ops = {
526         .pmd_entry = madvise_cold_or_pageout_pte_range,
527 };
528
529 static void madvise_cold_page_range(struct mmu_gather *tlb,
530                              struct vm_area_struct *vma,
531                              unsigned long addr, unsigned long end)
532 {
533         struct madvise_walk_private walk_private = {
534                 .pageout = false,
535                 .tlb = tlb,
536         };
537
538         tlb_start_vma(tlb, vma);
539         walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private);
540         tlb_end_vma(tlb, vma);
541 }
542
543 static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
544 {
545         return !(vma->vm_flags & (VM_LOCKED|VM_PFNMAP|VM_HUGETLB));
546 }
547
548 static long madvise_cold(struct vm_area_struct *vma,
549                         struct vm_area_struct **prev,
550                         unsigned long start_addr, unsigned long end_addr)
551 {
552         struct mm_struct *mm = vma->vm_mm;
553         struct mmu_gather tlb;
554
555         *prev = vma;
556         if (!can_madv_lru_vma(vma))
557                 return -EINVAL;
558
559         lru_add_drain();
560         tlb_gather_mmu(&tlb, mm);
561         madvise_cold_page_range(&tlb, vma, start_addr, end_addr);
562         tlb_finish_mmu(&tlb);
563
564         return 0;
565 }
566
567 static void madvise_pageout_page_range(struct mmu_gather *tlb,
568                              struct vm_area_struct *vma,
569                              unsigned long addr, unsigned long end)
570 {
571         struct madvise_walk_private walk_private = {
572                 .pageout = true,
573                 .tlb = tlb,
574         };
575
576         tlb_start_vma(tlb, vma);
577         walk_page_range(vma->vm_mm, addr, end, &cold_walk_ops, &walk_private);
578         tlb_end_vma(tlb, vma);
579 }
580
581 static long madvise_pageout(struct vm_area_struct *vma,
582                         struct vm_area_struct **prev,
583                         unsigned long start_addr, unsigned long end_addr)
584 {
585         struct mm_struct *mm = vma->vm_mm;
586         struct mmu_gather tlb;
587
588         *prev = vma;
589         if (!can_madv_lru_vma(vma))
590                 return -EINVAL;
591
592         /*
593          * If the VMA belongs to a private file mapping, there can be private
594          * dirty pages which can be paged out if even this process is neither
595          * owner nor write capable of the file. We allow private file mappings
596          * further to pageout dirty anon pages.
597          */
598         if (!vma_is_anonymous(vma) && (!can_do_file_pageout(vma) &&
599                                 (vma->vm_flags & VM_MAYSHARE)))
600                 return 0;
601
602         lru_add_drain();
603         tlb_gather_mmu(&tlb, mm);
604         madvise_pageout_page_range(&tlb, vma, start_addr, end_addr);
605         tlb_finish_mmu(&tlb);
606
607         return 0;
608 }
609
610 static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
611                                 unsigned long end, struct mm_walk *walk)
612
613 {
614         struct mmu_gather *tlb = walk->private;
615         struct mm_struct *mm = tlb->mm;
616         struct vm_area_struct *vma = walk->vma;
617         spinlock_t *ptl;
618         pte_t *orig_pte, *pte, ptent;
619         struct folio *folio;
620         struct page *page;
621         int nr_swap = 0;
622         unsigned long next;
623
624         next = pmd_addr_end(addr, end);
625         if (pmd_trans_huge(*pmd))
626                 if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next))
627                         goto next;
628
629         if (pmd_trans_unstable(pmd))
630                 return 0;
631
632         tlb_change_page_size(tlb, PAGE_SIZE);
633         orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
634         flush_tlb_batched_pending(mm);
635         arch_enter_lazy_mmu_mode();
636         for (; addr != end; pte++, addr += PAGE_SIZE) {
637                 ptent = *pte;
638
639                 if (pte_none(ptent))
640                         continue;
641                 /*
642                  * If the pte has swp_entry, just clear page table to
643                  * prevent swap-in which is more expensive rather than
644                  * (page allocation + zeroing).
645                  */
646                 if (!pte_present(ptent)) {
647                         swp_entry_t entry;
648
649                         entry = pte_to_swp_entry(ptent);
650                         if (!non_swap_entry(entry)) {
651                                 nr_swap--;
652                                 free_swap_and_cache(entry);
653                                 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
654                         } else if (is_hwpoison_entry(entry) ||
655                                    is_swapin_error_entry(entry)) {
656                                 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
657                         }
658                         continue;
659                 }
660
661                 page = vm_normal_page(vma, addr, ptent);
662                 if (!page || is_zone_device_page(page))
663                         continue;
664                 folio = page_folio(page);
665
666                 /*
667                  * If pmd isn't transhuge but the folio is large and
668                  * is owned by only this process, split it and
669                  * deactivate all pages.
670                  */
671                 if (folio_test_large(folio)) {
672                         if (folio_mapcount(folio) != 1)
673                                 goto out;
674                         folio_get(folio);
675                         if (!folio_trylock(folio)) {
676                                 folio_put(folio);
677                                 goto out;
678                         }
679                         pte_unmap_unlock(orig_pte, ptl);
680                         if (split_folio(folio)) {
681                                 folio_unlock(folio);
682                                 folio_put(folio);
683                                 orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
684                                 goto out;
685                         }
686                         folio_unlock(folio);
687                         folio_put(folio);
688                         orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
689                         pte--;
690                         addr -= PAGE_SIZE;
691                         continue;
692                 }
693
694                 if (folio_test_swapcache(folio) || folio_test_dirty(folio)) {
695                         if (!folio_trylock(folio))
696                                 continue;
697                         /*
698                          * If folio is shared with others, we mustn't clear
699                          * the folio's dirty flag.
700                          */
701                         if (folio_mapcount(folio) != 1) {
702                                 folio_unlock(folio);
703                                 continue;
704                         }
705
706                         if (folio_test_swapcache(folio) &&
707                             !folio_free_swap(folio)) {
708                                 folio_unlock(folio);
709                                 continue;
710                         }
711
712                         folio_clear_dirty(folio);
713                         folio_unlock(folio);
714                 }
715
716                 if (pte_young(ptent) || pte_dirty(ptent)) {
717                         /*
718                          * Some of architecture(ex, PPC) don't update TLB
719                          * with set_pte_at and tlb_remove_tlb_entry so for
720                          * the portability, remap the pte with old|clean
721                          * after pte clearing.
722                          */
723                         ptent = ptep_get_and_clear_full(mm, addr, pte,
724                                                         tlb->fullmm);
725
726                         ptent = pte_mkold(ptent);
727                         ptent = pte_mkclean(ptent);
728                         set_pte_at(mm, addr, pte, ptent);
729                         tlb_remove_tlb_entry(tlb, pte, addr);
730                 }
731                 mark_page_lazyfree(&folio->page);
732         }
733 out:
734         if (nr_swap) {
735                 if (current->mm == mm)
736                         sync_mm_rss(mm);
737
738                 add_mm_counter(mm, MM_SWAPENTS, nr_swap);
739         }
740         arch_leave_lazy_mmu_mode();
741         pte_unmap_unlock(orig_pte, ptl);
742         cond_resched();
743 next:
744         return 0;
745 }
746
747 static const struct mm_walk_ops madvise_free_walk_ops = {
748         .pmd_entry              = madvise_free_pte_range,
749 };
750
751 static int madvise_free_single_vma(struct vm_area_struct *vma,
752                         unsigned long start_addr, unsigned long end_addr)
753 {
754         struct mm_struct *mm = vma->vm_mm;
755         struct mmu_notifier_range range;
756         struct mmu_gather tlb;
757
758         /* MADV_FREE works for only anon vma at the moment */
759         if (!vma_is_anonymous(vma))
760                 return -EINVAL;
761
762         range.start = max(vma->vm_start, start_addr);
763         if (range.start >= vma->vm_end)
764                 return -EINVAL;
765         range.end = min(vma->vm_end, end_addr);
766         if (range.end <= vma->vm_start)
767                 return -EINVAL;
768         mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
769                                 range.start, range.end);
770
771         lru_add_drain();
772         tlb_gather_mmu(&tlb, mm);
773         update_hiwater_rss(mm);
774
775         mmu_notifier_invalidate_range_start(&range);
776         tlb_start_vma(&tlb, vma);
777         walk_page_range(vma->vm_mm, range.start, range.end,
778                         &madvise_free_walk_ops, &tlb);
779         tlb_end_vma(&tlb, vma);
780         mmu_notifier_invalidate_range_end(&range);
781         tlb_finish_mmu(&tlb);
782
783         return 0;
784 }
785
786 /*
787  * Application no longer needs these pages.  If the pages are dirty,
788  * it's OK to just throw them away.  The app will be more careful about
789  * data it wants to keep.  Be sure to free swap resources too.  The
790  * zap_page_range_single call sets things up for shrink_active_list to actually
791  * free these pages later if no one else has touched them in the meantime,
792  * although we could add these pages to a global reuse list for
793  * shrink_active_list to pick up before reclaiming other pages.
794  *
795  * NB: This interface discards data rather than pushes it out to swap,
796  * as some implementations do.  This has performance implications for
797  * applications like large transactional databases which want to discard
798  * pages in anonymous maps after committing to backing store the data
799  * that was kept in them.  There is no reason to write this data out to
800  * the swap area if the application is discarding it.
801  *
802  * An interface that causes the system to free clean pages and flush
803  * dirty pages is already available as msync(MS_INVALIDATE).
804  */
805 static long madvise_dontneed_single_vma(struct vm_area_struct *vma,
806                                         unsigned long start, unsigned long end)
807 {
808         zap_page_range_single(vma, start, end - start, NULL);
809         return 0;
810 }
811
812 static bool madvise_dontneed_free_valid_vma(struct vm_area_struct *vma,
813                                             unsigned long start,
814                                             unsigned long *end,
815                                             int behavior)
816 {
817         if (!is_vm_hugetlb_page(vma)) {
818                 unsigned int forbidden = VM_PFNMAP;
819
820                 if (behavior != MADV_DONTNEED_LOCKED)
821                         forbidden |= VM_LOCKED;
822
823                 return !(vma->vm_flags & forbidden);
824         }
825
826         if (behavior != MADV_DONTNEED && behavior != MADV_DONTNEED_LOCKED)
827                 return false;
828         if (start & ~huge_page_mask(hstate_vma(vma)))
829                 return false;
830
831         /*
832          * Madvise callers expect the length to be rounded up to PAGE_SIZE
833          * boundaries, and may be unaware that this VMA uses huge pages.
834          * Avoid unexpected data loss by rounding down the number of
835          * huge pages freed.
836          */
837         *end = ALIGN_DOWN(*end, huge_page_size(hstate_vma(vma)));
838
839         return true;
840 }
841
842 static long madvise_dontneed_free(struct vm_area_struct *vma,
843                                   struct vm_area_struct **prev,
844                                   unsigned long start, unsigned long end,
845                                   int behavior)
846 {
847         struct mm_struct *mm = vma->vm_mm;
848
849         *prev = vma;
850         if (!madvise_dontneed_free_valid_vma(vma, start, &end, behavior))
851                 return -EINVAL;
852
853         if (start == end)
854                 return 0;
855
856         if (!userfaultfd_remove(vma, start, end)) {
857                 *prev = NULL; /* mmap_lock has been dropped, prev is stale */
858
859                 mmap_read_lock(mm);
860                 vma = find_vma(mm, start);
861                 if (!vma)
862                         return -ENOMEM;
863                 if (start < vma->vm_start) {
864                         /*
865                          * This "vma" under revalidation is the one
866                          * with the lowest vma->vm_start where start
867                          * is also < vma->vm_end. If start <
868                          * vma->vm_start it means an hole materialized
869                          * in the user address space within the
870                          * virtual range passed to MADV_DONTNEED
871                          * or MADV_FREE.
872                          */
873                         return -ENOMEM;
874                 }
875                 /*
876                  * Potential end adjustment for hugetlb vma is OK as
877                  * the check below keeps end within vma.
878                  */
879                 if (!madvise_dontneed_free_valid_vma(vma, start, &end,
880                                                      behavior))
881                         return -EINVAL;
882                 if (end > vma->vm_end) {
883                         /*
884                          * Don't fail if end > vma->vm_end. If the old
885                          * vma was split while the mmap_lock was
886                          * released the effect of the concurrent
887                          * operation may not cause madvise() to
888                          * have an undefined result. There may be an
889                          * adjacent next vma that we'll walk
890                          * next. userfaultfd_remove() will generate an
891                          * UFFD_EVENT_REMOVE repetition on the
892                          * end-vma->vm_end range, but the manager can
893                          * handle a repetition fine.
894                          */
895                         end = vma->vm_end;
896                 }
897                 VM_WARN_ON(start >= end);
898         }
899
900         if (behavior == MADV_DONTNEED || behavior == MADV_DONTNEED_LOCKED)
901                 return madvise_dontneed_single_vma(vma, start, end);
902         else if (behavior == MADV_FREE)
903                 return madvise_free_single_vma(vma, start, end);
904         else
905                 return -EINVAL;
906 }
907
908 static long madvise_populate(struct vm_area_struct *vma,
909                              struct vm_area_struct **prev,
910                              unsigned long start, unsigned long end,
911                              int behavior)
912 {
913         const bool write = behavior == MADV_POPULATE_WRITE;
914         struct mm_struct *mm = vma->vm_mm;
915         unsigned long tmp_end;
916         int locked = 1;
917         long pages;
918
919         *prev = vma;
920
921         while (start < end) {
922                 /*
923                  * We might have temporarily dropped the lock. For example,
924                  * our VMA might have been split.
925                  */
926                 if (!vma || start >= vma->vm_end) {
927                         vma = vma_lookup(mm, start);
928                         if (!vma)
929                                 return -ENOMEM;
930                 }
931
932                 tmp_end = min_t(unsigned long, end, vma->vm_end);
933                 /* Populate (prefault) page tables readable/writable. */
934                 pages = faultin_vma_page_range(vma, start, tmp_end, write,
935                                                &locked);
936                 if (!locked) {
937                         mmap_read_lock(mm);
938                         locked = 1;
939                         *prev = NULL;
940                         vma = NULL;
941                 }
942                 if (pages < 0) {
943                         switch (pages) {
944                         case -EINTR:
945                                 return -EINTR;
946                         case -EINVAL: /* Incompatible mappings / permissions. */
947                                 return -EINVAL;
948                         case -EHWPOISON:
949                                 return -EHWPOISON;
950                         case -EFAULT: /* VM_FAULT_SIGBUS or VM_FAULT_SIGSEGV */
951                                 return -EFAULT;
952                         default:
953                                 pr_warn_once("%s: unhandled return value: %ld\n",
954                                              __func__, pages);
955                                 fallthrough;
956                         case -ENOMEM:
957                                 return -ENOMEM;
958                         }
959                 }
960                 start += pages * PAGE_SIZE;
961         }
962         return 0;
963 }
964
965 /*
966  * Application wants to free up the pages and associated backing store.
967  * This is effectively punching a hole into the middle of a file.
968  */
969 static long madvise_remove(struct vm_area_struct *vma,
970                                 struct vm_area_struct **prev,
971                                 unsigned long start, unsigned long end)
972 {
973         loff_t offset;
974         int error;
975         struct file *f;
976         struct mm_struct *mm = vma->vm_mm;
977
978         *prev = NULL;   /* tell sys_madvise we drop mmap_lock */
979
980         if (vma->vm_flags & VM_LOCKED)
981                 return -EINVAL;
982
983         f = vma->vm_file;
984
985         if (!f || !f->f_mapping || !f->f_mapping->host) {
986                         return -EINVAL;
987         }
988
989         if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
990                 return -EACCES;
991
992         offset = (loff_t)(start - vma->vm_start)
993                         + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
994
995         /*
996          * Filesystem's fallocate may need to take i_rwsem.  We need to
997          * explicitly grab a reference because the vma (and hence the
998          * vma's reference to the file) can go away as soon as we drop
999          * mmap_lock.
1000          */
1001         get_file(f);
1002         if (userfaultfd_remove(vma, start, end)) {
1003                 /* mmap_lock was not released by userfaultfd_remove() */
1004                 mmap_read_unlock(mm);
1005         }
1006         error = vfs_fallocate(f,
1007                                 FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
1008                                 offset, end - start);
1009         fput(f);
1010         mmap_read_lock(mm);
1011         return error;
1012 }
1013
1014 /*
1015  * Apply an madvise behavior to a region of a vma.  madvise_update_vma
1016  * will handle splitting a vm area into separate areas, each area with its own
1017  * behavior.
1018  */
1019 static int madvise_vma_behavior(struct vm_area_struct *vma,
1020                                 struct vm_area_struct **prev,
1021                                 unsigned long start, unsigned long end,
1022                                 unsigned long behavior)
1023 {
1024         int error;
1025         struct anon_vma_name *anon_name;
1026         unsigned long new_flags = vma->vm_flags;
1027
1028         switch (behavior) {
1029         case MADV_REMOVE:
1030                 return madvise_remove(vma, prev, start, end);
1031         case MADV_WILLNEED:
1032                 return madvise_willneed(vma, prev, start, end);
1033         case MADV_COLD:
1034                 return madvise_cold(vma, prev, start, end);
1035         case MADV_PAGEOUT:
1036                 return madvise_pageout(vma, prev, start, end);
1037         case MADV_FREE:
1038         case MADV_DONTNEED:
1039         case MADV_DONTNEED_LOCKED:
1040                 return madvise_dontneed_free(vma, prev, start, end, behavior);
1041         case MADV_POPULATE_READ:
1042         case MADV_POPULATE_WRITE:
1043                 return madvise_populate(vma, prev, start, end, behavior);
1044         case MADV_NORMAL:
1045                 new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
1046                 break;
1047         case MADV_SEQUENTIAL:
1048                 new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
1049                 break;
1050         case MADV_RANDOM:
1051                 new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
1052                 break;
1053         case MADV_DONTFORK:
1054                 new_flags |= VM_DONTCOPY;
1055                 break;
1056         case MADV_DOFORK:
1057                 if (vma->vm_flags & VM_IO)
1058                         return -EINVAL;
1059                 new_flags &= ~VM_DONTCOPY;
1060                 break;
1061         case MADV_WIPEONFORK:
1062                 /* MADV_WIPEONFORK is only supported on anonymous memory. */
1063                 if (vma->vm_file || vma->vm_flags & VM_SHARED)
1064                         return -EINVAL;
1065                 new_flags |= VM_WIPEONFORK;
1066                 break;
1067         case MADV_KEEPONFORK:
1068                 new_flags &= ~VM_WIPEONFORK;
1069                 break;
1070         case MADV_DONTDUMP:
1071                 new_flags |= VM_DONTDUMP;
1072                 break;
1073         case MADV_DODUMP:
1074                 if (!is_vm_hugetlb_page(vma) && new_flags & VM_SPECIAL)
1075                         return -EINVAL;
1076                 new_flags &= ~VM_DONTDUMP;
1077                 break;
1078         case MADV_MERGEABLE:
1079         case MADV_UNMERGEABLE:
1080                 error = ksm_madvise(vma, start, end, behavior, &new_flags);
1081                 if (error)
1082                         goto out;
1083                 break;
1084         case MADV_HUGEPAGE:
1085         case MADV_NOHUGEPAGE:
1086                 error = hugepage_madvise(vma, &new_flags, behavior);
1087                 if (error)
1088                         goto out;
1089                 break;
1090         case MADV_COLLAPSE:
1091                 return madvise_collapse(vma, prev, start, end);
1092         }
1093
1094         anon_name = anon_vma_name(vma);
1095         anon_vma_name_get(anon_name);
1096         error = madvise_update_vma(vma, prev, start, end, new_flags,
1097                                    anon_name);
1098         anon_vma_name_put(anon_name);
1099
1100 out:
1101         /*
1102          * madvise() returns EAGAIN if kernel resources, such as
1103          * slab, are temporarily unavailable.
1104          */
1105         if (error == -ENOMEM)
1106                 error = -EAGAIN;
1107         return error;
1108 }
1109
1110 #ifdef CONFIG_MEMORY_FAILURE
1111 /*
1112  * Error injection support for memory error handling.
1113  */
1114 static int madvise_inject_error(int behavior,
1115                 unsigned long start, unsigned long end)
1116 {
1117         unsigned long size;
1118
1119         if (!capable(CAP_SYS_ADMIN))
1120                 return -EPERM;
1121
1122
1123         for (; start < end; start += size) {
1124                 unsigned long pfn;
1125                 struct page *page;
1126                 int ret;
1127
1128                 ret = get_user_pages_fast(start, 1, 0, &page);
1129                 if (ret != 1)
1130                         return ret;
1131                 pfn = page_to_pfn(page);
1132
1133                 /*
1134                  * When soft offlining hugepages, after migrating the page
1135                  * we dissolve it, therefore in the second loop "page" will
1136                  * no longer be a compound page.
1137                  */
1138                 size = page_size(compound_head(page));
1139
1140                 if (behavior == MADV_SOFT_OFFLINE) {
1141                         pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
1142                                  pfn, start);
1143                         ret = soft_offline_page(pfn, MF_COUNT_INCREASED);
1144                 } else {
1145                         pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
1146                                  pfn, start);
1147                         ret = memory_failure(pfn, MF_COUNT_INCREASED | MF_SW_SIMULATED);
1148                         if (ret == -EOPNOTSUPP)
1149                                 ret = 0;
1150                 }
1151
1152                 if (ret)
1153                         return ret;
1154         }
1155
1156         return 0;
1157 }
1158 #endif
1159
1160 static bool
1161 madvise_behavior_valid(int behavior)
1162 {
1163         switch (behavior) {
1164         case MADV_DOFORK:
1165         case MADV_DONTFORK:
1166         case MADV_NORMAL:
1167         case MADV_SEQUENTIAL:
1168         case MADV_RANDOM:
1169         case MADV_REMOVE:
1170         case MADV_WILLNEED:
1171         case MADV_DONTNEED:
1172         case MADV_DONTNEED_LOCKED:
1173         case MADV_FREE:
1174         case MADV_COLD:
1175         case MADV_PAGEOUT:
1176         case MADV_POPULATE_READ:
1177         case MADV_POPULATE_WRITE:
1178 #ifdef CONFIG_KSM
1179         case MADV_MERGEABLE:
1180         case MADV_UNMERGEABLE:
1181 #endif
1182 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1183         case MADV_HUGEPAGE:
1184         case MADV_NOHUGEPAGE:
1185         case MADV_COLLAPSE:
1186 #endif
1187         case MADV_DONTDUMP:
1188         case MADV_DODUMP:
1189         case MADV_WIPEONFORK:
1190         case MADV_KEEPONFORK:
1191 #ifdef CONFIG_MEMORY_FAILURE
1192         case MADV_SOFT_OFFLINE:
1193         case MADV_HWPOISON:
1194 #endif
1195                 return true;
1196
1197         default:
1198                 return false;
1199         }
1200 }
1201
1202 static bool process_madvise_behavior_valid(int behavior)
1203 {
1204         switch (behavior) {
1205         case MADV_COLD:
1206         case MADV_PAGEOUT:
1207         case MADV_WILLNEED:
1208         case MADV_COLLAPSE:
1209                 return true;
1210         default:
1211                 return false;
1212         }
1213 }
1214
1215 /*
1216  * Walk the vmas in range [start,end), and call the visit function on each one.
1217  * The visit function will get start and end parameters that cover the overlap
1218  * between the current vma and the original range.  Any unmapped regions in the
1219  * original range will result in this function returning -ENOMEM while still
1220  * calling the visit function on all of the existing vmas in the range.
1221  * Must be called with the mmap_lock held for reading or writing.
1222  */
1223 static
1224 int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
1225                       unsigned long end, unsigned long arg,
1226                       int (*visit)(struct vm_area_struct *vma,
1227                                    struct vm_area_struct **prev, unsigned long start,
1228                                    unsigned long end, unsigned long arg))
1229 {
1230         struct vm_area_struct *vma;
1231         struct vm_area_struct *prev;
1232         unsigned long tmp;
1233         int unmapped_error = 0;
1234
1235         /*
1236          * If the interval [start,end) covers some unmapped address
1237          * ranges, just ignore them, but return -ENOMEM at the end.
1238          * - different from the way of handling in mlock etc.
1239          */
1240         vma = find_vma_prev(mm, start, &prev);
1241         if (vma && start > vma->vm_start)
1242                 prev = vma;
1243
1244         for (;;) {
1245                 int error;
1246
1247                 /* Still start < end. */
1248                 if (!vma)
1249                         return -ENOMEM;
1250
1251                 /* Here start < (end|vma->vm_end). */
1252                 if (start < vma->vm_start) {
1253                         unmapped_error = -ENOMEM;
1254                         start = vma->vm_start;
1255                         if (start >= end)
1256                                 break;
1257                 }
1258
1259                 /* Here vma->vm_start <= start < (end|vma->vm_end) */
1260                 tmp = vma->vm_end;
1261                 if (end < tmp)
1262                         tmp = end;
1263
1264                 /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
1265                 error = visit(vma, &prev, start, tmp, arg);
1266                 if (error)
1267                         return error;
1268                 start = tmp;
1269                 if (prev && start < prev->vm_end)
1270                         start = prev->vm_end;
1271                 if (start >= end)
1272                         break;
1273                 if (prev)
1274                         vma = find_vma(mm, prev->vm_end);
1275                 else    /* madvise_remove dropped mmap_lock */
1276                         vma = find_vma(mm, start);
1277         }
1278
1279         return unmapped_error;
1280 }
1281
1282 #ifdef CONFIG_ANON_VMA_NAME
1283 static int madvise_vma_anon_name(struct vm_area_struct *vma,
1284                                  struct vm_area_struct **prev,
1285                                  unsigned long start, unsigned long end,
1286                                  unsigned long anon_name)
1287 {
1288         int error;
1289
1290         /* Only anonymous mappings can be named */
1291         if (vma->vm_file && !vma_is_anon_shmem(vma))
1292                 return -EBADF;
1293
1294         error = madvise_update_vma(vma, prev, start, end, vma->vm_flags,
1295                                    (struct anon_vma_name *)anon_name);
1296
1297         /*
1298          * madvise() returns EAGAIN if kernel resources, such as
1299          * slab, are temporarily unavailable.
1300          */
1301         if (error == -ENOMEM)
1302                 error = -EAGAIN;
1303         return error;
1304 }
1305
1306 int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
1307                           unsigned long len_in, struct anon_vma_name *anon_name)
1308 {
1309         unsigned long end;
1310         unsigned long len;
1311
1312         if (start & ~PAGE_MASK)
1313                 return -EINVAL;
1314         len = (len_in + ~PAGE_MASK) & PAGE_MASK;
1315
1316         /* Check to see whether len was rounded up from small -ve to zero */
1317         if (len_in && !len)
1318                 return -EINVAL;
1319
1320         end = start + len;
1321         if (end < start)
1322                 return -EINVAL;
1323
1324         if (end == start)
1325                 return 0;
1326
1327         return madvise_walk_vmas(mm, start, end, (unsigned long)anon_name,
1328                                  madvise_vma_anon_name);
1329 }
1330 #endif /* CONFIG_ANON_VMA_NAME */
1331 /*
1332  * The madvise(2) system call.
1333  *
1334  * Applications can use madvise() to advise the kernel how it should
1335  * handle paging I/O in this VM area.  The idea is to help the kernel
1336  * use appropriate read-ahead and caching techniques.  The information
1337  * provided is advisory only, and can be safely disregarded by the
1338  * kernel without affecting the correct operation of the application.
1339  *
1340  * behavior values:
1341  *  MADV_NORMAL - the default behavior is to read clusters.  This
1342  *              results in some read-ahead and read-behind.
1343  *  MADV_RANDOM - the system should read the minimum amount of data
1344  *              on any access, since it is unlikely that the appli-
1345  *              cation will need more than what it asks for.
1346  *  MADV_SEQUENTIAL - pages in the given range will probably be accessed
1347  *              once, so they can be aggressively read ahead, and
1348  *              can be freed soon after they are accessed.
1349  *  MADV_WILLNEED - the application is notifying the system to read
1350  *              some pages ahead.
1351  *  MADV_DONTNEED - the application is finished with the given range,
1352  *              so the kernel can free resources associated with it.
1353  *  MADV_FREE - the application marks pages in the given range as lazy free,
1354  *              where actual purges are postponed until memory pressure happens.
1355  *  MADV_REMOVE - the application wants to free up the given range of
1356  *              pages and associated backing store.
1357  *  MADV_DONTFORK - omit this area from child's address space when forking:
1358  *              typically, to avoid COWing pages pinned by get_user_pages().
1359  *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
1360  *  MADV_WIPEONFORK - present the child process with zero-filled memory in this
1361  *              range after a fork.
1362  *  MADV_KEEPONFORK - undo the effect of MADV_WIPEONFORK
1363  *  MADV_HWPOISON - trigger memory error handler as if the given memory range
1364  *              were corrupted by unrecoverable hardware memory failure.
1365  *  MADV_SOFT_OFFLINE - try to soft-offline the given range of memory.
1366  *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
1367  *              this area with pages of identical content from other such areas.
1368  *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
1369  *  MADV_HUGEPAGE - the application wants to back the given range by transparent
1370  *              huge pages in the future. Existing pages might be coalesced and
1371  *              new pages might be allocated as THP.
1372  *  MADV_NOHUGEPAGE - mark the given range as not worth being backed by
1373  *              transparent huge pages so the existing pages will not be
1374  *              coalesced into THP and new pages will not be allocated as THP.
1375  *  MADV_COLLAPSE - synchronously coalesce pages into new THP.
1376  *  MADV_DONTDUMP - the application wants to prevent pages in the given range
1377  *              from being included in its core dump.
1378  *  MADV_DODUMP - cancel MADV_DONTDUMP: no longer exclude from core dump.
1379  *  MADV_COLD - the application is not expected to use this memory soon,
1380  *              deactivate pages in this range so that they can be reclaimed
1381  *              easily if memory pressure happens.
1382  *  MADV_PAGEOUT - the application is not expected to use this memory soon,
1383  *              page out the pages in this range immediately.
1384  *  MADV_POPULATE_READ - populate (prefault) page tables readable by
1385  *              triggering read faults if required
1386  *  MADV_POPULATE_WRITE - populate (prefault) page tables writable by
1387  *              triggering write faults if required
1388  *
1389  * return values:
1390  *  zero    - success
1391  *  -EINVAL - start + len < 0, start is not page-aligned,
1392  *              "behavior" is not a valid value, or application
1393  *              is attempting to release locked or shared pages,
1394  *              or the specified address range includes file, Huge TLB,
1395  *              MAP_SHARED or VMPFNMAP range.
1396  *  -ENOMEM - addresses in the specified range are not currently
1397  *              mapped, or are outside the AS of the process.
1398  *  -EIO    - an I/O error occurred while paging in data.
1399  *  -EBADF  - map exists, but area maps something that isn't a file.
1400  *  -EAGAIN - a kernel resource was temporarily unavailable.
1401  */
1402 int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior)
1403 {
1404         unsigned long end;
1405         int error;
1406         int write;
1407         size_t len;
1408         struct blk_plug plug;
1409
1410         start = untagged_addr(start);
1411
1412         if (!madvise_behavior_valid(behavior))
1413                 return -EINVAL;
1414
1415         if (!PAGE_ALIGNED(start))
1416                 return -EINVAL;
1417         len = PAGE_ALIGN(len_in);
1418
1419         /* Check to see whether len was rounded up from small -ve to zero */
1420         if (len_in && !len)
1421                 return -EINVAL;
1422
1423         end = start + len;
1424         if (end < start)
1425                 return -EINVAL;
1426
1427         if (end == start)
1428                 return 0;
1429
1430 #ifdef CONFIG_MEMORY_FAILURE
1431         if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
1432                 return madvise_inject_error(behavior, start, start + len_in);
1433 #endif
1434
1435         write = madvise_need_mmap_write(behavior);
1436         if (write) {
1437                 if (mmap_write_lock_killable(mm))
1438                         return -EINTR;
1439         } else {
1440                 mmap_read_lock(mm);
1441         }
1442
1443         blk_start_plug(&plug);
1444         error = madvise_walk_vmas(mm, start, end, behavior,
1445                         madvise_vma_behavior);
1446         blk_finish_plug(&plug);
1447         if (write)
1448                 mmap_write_unlock(mm);
1449         else
1450                 mmap_read_unlock(mm);
1451
1452         return error;
1453 }
1454
1455 SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
1456 {
1457         return do_madvise(current->mm, start, len_in, behavior);
1458 }
1459
1460 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], iovec;
1465         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         if (flags != 0) {
1473                 ret = -EINVAL;
1474                 goto out;
1475         }
1476
1477         ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
1478         if (ret < 0)
1479                 goto out;
1480
1481         task = pidfd_get_task(pidfd, &f_flags);
1482         if (IS_ERR(task)) {
1483                 ret = PTR_ERR(task);
1484                 goto free_iov;
1485         }
1486
1487         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         mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
1494         if (IS_ERR_OR_NULL(mm)) {
1495                 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         if (!capable(CAP_SYS_NICE)) {
1504                 ret = -EPERM;
1505                 goto release_mm;
1506         }
1507
1508         total_len = iov_iter_count(&iter);
1509
1510         while (iov_iter_count(&iter)) {
1511                 iovec = iov_iter_iovec(&iter);
1512                 ret = do_madvise(mm, (unsigned long)iovec.iov_base,
1513                                         iovec.iov_len, behavior);
1514                 if (ret < 0)
1515                         break;
1516                 iov_iter_advance(&iter, iovec.iov_len);
1517         }
1518
1519         ret = (total_len - iov_iter_count(&iter)) ? : ret;
1520
1521 release_mm:
1522         mmput(mm);
1523 release_task:
1524         put_task_struct(task);
1525 free_iov:
1526         kfree(iov);
1527 out:
1528         return ret;
1529 }