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1/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
6 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
7 */
8
9#include <linux/slab.h>
10#include <linux/backing-dev.h>
11#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
17#include <linux/capability.h>
18#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
29#include <linux/mmu_notifier.h>
30#include <linux/perf_event.h>
31#include <linux/audit.h>
32#include <linux/khugepaged.h>
33
34#include <asm/uaccess.h>
35#include <asm/cacheflush.h>
36#include <asm/tlb.h>
37#include <asm/mmu_context.h>
38
39#include "internal.h"
40
41#ifndef arch_mmap_check
42#define arch_mmap_check(addr, len, flags) (0)
43#endif
44
45#ifndef arch_rebalance_pgtables
46#define arch_rebalance_pgtables(addr, len) (addr)
47#endif
48
49static void unmap_region(struct mm_struct *mm,
50 struct vm_area_struct *vma, struct vm_area_struct *prev,
51 unsigned long start, unsigned long end);
52
53/*
54 * WARNING: the debugging will use recursive algorithms so never enable this
55 * unless you know what you are doing.
56 */
57#undef DEBUG_MM_RB
58
59/* description of effects of mapping type and prot in current implementation.
60 * this is due to the limited x86 page protection hardware. The expected
61 * behavior is in parens:
62 *
63 * map_type prot
64 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
65 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (yes) yes w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
70 * w: (no) no w: (no) no w: (copy) copy w: (no) no
71 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
72 *
73 */
74pgprot_t protection_map[16] = {
75 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
76 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
77};
78
79pgprot_t vm_get_page_prot(unsigned long vm_flags)
80{
81 return __pgprot(pgprot_val(protection_map[vm_flags &
82 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
83 pgprot_val(arch_vm_get_page_prot(vm_flags)));
84}
85EXPORT_SYMBOL(vm_get_page_prot);
86
87int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
88int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
89int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
90/*
91 * Make sure vm_committed_as in one cacheline and not cacheline shared with
92 * other variables. It can be updated by several CPUs frequently.
93 */
94struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
95
96/*
97 * Check that a process has enough memory to allocate a new virtual
98 * mapping. 0 means there is enough memory for the allocation to
99 * succeed and -ENOMEM implies there is not.
100 *
101 * We currently support three overcommit policies, which are set via the
102 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
103 *
104 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
105 * Additional code 2002 Jul 20 by Robert Love.
106 *
107 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
108 *
109 * Note this is a helper function intended to be used by LSMs which
110 * wish to use this logic.
111 */
112int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
113{
114 unsigned long free, allowed;
115
116 vm_acct_memory(pages);
117
118 /*
119 * Sometimes we want to use more memory than we have
120 */
121 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
122 return 0;
123
124 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
125 free = global_page_state(NR_FREE_PAGES);
126 free += global_page_state(NR_FILE_PAGES);
127
128 /*
129 * shmem pages shouldn't be counted as free in this
130 * case, they can't be purged, only swapped out, and
131 * that won't affect the overall amount of available
132 * memory in the system.
133 */
134 free -= global_page_state(NR_SHMEM);
135
136 free += nr_swap_pages;
137
138 /*
139 * Any slabs which are created with the
140 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
141 * which are reclaimable, under pressure. The dentry
142 * cache and most inode caches should fall into this
143 */
144 free += global_page_state(NR_SLAB_RECLAIMABLE);
145
146 /*
147 * Leave reserved pages. The pages are not for anonymous pages.
148 */
149 if (free <= totalreserve_pages)
150 goto error;
151 else
152 free -= totalreserve_pages;
153
154 /*
155 * Leave the last 3% for root
156 */
157 if (!cap_sys_admin)
158 free -= free / 32;
159
160 if (free > pages)
161 return 0;
162
163 goto error;
164 }
165
166 allowed = (totalram_pages - hugetlb_total_pages())
167 * sysctl_overcommit_ratio / 100;
168 /*
169 * Leave the last 3% for root
170 */
171 if (!cap_sys_admin)
172 allowed -= allowed / 32;
173 allowed += total_swap_pages;
174
175 /* Don't let a single process grow too big:
176 leave 3% of the size of this process for other processes */
177 if (mm)
178 allowed -= mm->total_vm / 32;
179
180 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
181 return 0;
182error:
183 vm_unacct_memory(pages);
184
185 return -ENOMEM;
186}
187
188/*
189 * Requires inode->i_mapping->i_mmap_mutex
190 */
191static void __remove_shared_vm_struct(struct vm_area_struct *vma,
192 struct file *file, struct address_space *mapping)
193{
194 if (vma->vm_flags & VM_DENYWRITE)
195 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
196 if (vma->vm_flags & VM_SHARED)
197 mapping->i_mmap_writable--;
198
199 flush_dcache_mmap_lock(mapping);
200 if (unlikely(vma->vm_flags & VM_NONLINEAR))
201 list_del_init(&vma->shared.vm_set.list);
202 else
203 vma_prio_tree_remove(vma, &mapping->i_mmap);
204 flush_dcache_mmap_unlock(mapping);
205}
206
207/*
208 * Unlink a file-based vm structure from its prio_tree, to hide
209 * vma from rmap and vmtruncate before freeing its page tables.
210 */
211void unlink_file_vma(struct vm_area_struct *vma)
212{
213 struct file *file = vma->vm_file;
214
215 if (file) {
216 struct address_space *mapping = file->f_mapping;
217 mutex_lock(&mapping->i_mmap_mutex);
218 __remove_shared_vm_struct(vma, file, mapping);
219 mutex_unlock(&mapping->i_mmap_mutex);
220 }
221}
222
223/*
224 * Close a vm structure and free it, returning the next.
225 */
226static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
227{
228 struct vm_area_struct *next = vma->vm_next;
229
230 might_sleep();
231 if (vma->vm_ops && vma->vm_ops->close)
232 vma->vm_ops->close(vma);
233 if (vma->vm_file) {
234 fput(vma->vm_file);
235 if (vma->vm_flags & VM_EXECUTABLE)
236 removed_exe_file_vma(vma->vm_mm);
237 }
238 mpol_put(vma_policy(vma));
239 kmem_cache_free(vm_area_cachep, vma);
240 return next;
241}
242
243SYSCALL_DEFINE1(brk, unsigned long, brk)
244{
245 unsigned long rlim, retval;
246 unsigned long newbrk, oldbrk;
247 struct mm_struct *mm = current->mm;
248 unsigned long min_brk;
249
250 down_write(&mm->mmap_sem);
251
252#ifdef CONFIG_COMPAT_BRK
253 /*
254 * CONFIG_COMPAT_BRK can still be overridden by setting
255 * randomize_va_space to 2, which will still cause mm->start_brk
256 * to be arbitrarily shifted
257 */
258 if (current->brk_randomized)
259 min_brk = mm->start_brk;
260 else
261 min_brk = mm->end_data;
262#else
263 min_brk = mm->start_brk;
264#endif
265 if (brk < min_brk)
266 goto out;
267
268 /*
269 * Check against rlimit here. If this check is done later after the test
270 * of oldbrk with newbrk then it can escape the test and let the data
271 * segment grow beyond its set limit the in case where the limit is
272 * not page aligned -Ram Gupta
273 */
274 rlim = rlimit(RLIMIT_DATA);
275 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
276 (mm->end_data - mm->start_data) > rlim)
277 goto out;
278
279 newbrk = PAGE_ALIGN(brk);
280 oldbrk = PAGE_ALIGN(mm->brk);
281 if (oldbrk == newbrk)
282 goto set_brk;
283
284 /* Always allow shrinking brk. */
285 if (brk <= mm->brk) {
286 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
287 goto set_brk;
288 goto out;
289 }
290
291 /* Check against existing mmap mappings. */
292 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
293 goto out;
294
295 /* Ok, looks good - let it rip. */
296 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
297 goto out;
298set_brk:
299 mm->brk = brk;
300out:
301 retval = mm->brk;
302 up_write(&mm->mmap_sem);
303 return retval;
304}
305
306#ifdef DEBUG_MM_RB
307static int browse_rb(struct rb_root *root)
308{
309 int i = 0, j;
310 struct rb_node *nd, *pn = NULL;
311 unsigned long prev = 0, pend = 0;
312
313 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
314 struct vm_area_struct *vma;
315 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
316 if (vma->vm_start < prev)
317 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
318 if (vma->vm_start < pend)
319 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
320 if (vma->vm_start > vma->vm_end)
321 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
322 i++;
323 pn = nd;
324 prev = vma->vm_start;
325 pend = vma->vm_end;
326 }
327 j = 0;
328 for (nd = pn; nd; nd = rb_prev(nd)) {
329 j++;
330 }
331 if (i != j)
332 printk("backwards %d, forwards %d\n", j, i), i = 0;
333 return i;
334}
335
336void validate_mm(struct mm_struct *mm)
337{
338 int bug = 0;
339 int i = 0;
340 struct vm_area_struct *tmp = mm->mmap;
341 while (tmp) {
342 tmp = tmp->vm_next;
343 i++;
344 }
345 if (i != mm->map_count)
346 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
347 i = browse_rb(&mm->mm_rb);
348 if (i != mm->map_count)
349 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
350 BUG_ON(bug);
351}
352#else
353#define validate_mm(mm) do { } while (0)
354#endif
355
356static struct vm_area_struct *
357find_vma_prepare(struct mm_struct *mm, unsigned long addr,
358 struct vm_area_struct **pprev, struct rb_node ***rb_link,
359 struct rb_node ** rb_parent)
360{
361 struct vm_area_struct * vma;
362 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
363
364 __rb_link = &mm->mm_rb.rb_node;
365 rb_prev = __rb_parent = NULL;
366 vma = NULL;
367
368 while (*__rb_link) {
369 struct vm_area_struct *vma_tmp;
370
371 __rb_parent = *__rb_link;
372 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
373
374 if (vma_tmp->vm_end > addr) {
375 vma = vma_tmp;
376 if (vma_tmp->vm_start <= addr)
377 break;
378 __rb_link = &__rb_parent->rb_left;
379 } else {
380 rb_prev = __rb_parent;
381 __rb_link = &__rb_parent->rb_right;
382 }
383 }
384
385 *pprev = NULL;
386 if (rb_prev)
387 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
388 *rb_link = __rb_link;
389 *rb_parent = __rb_parent;
390 return vma;
391}
392
393void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
394 struct rb_node **rb_link, struct rb_node *rb_parent)
395{
396 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
397 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
398}
399
400static void __vma_link_file(struct vm_area_struct *vma)
401{
402 struct file *file;
403
404 file = vma->vm_file;
405 if (file) {
406 struct address_space *mapping = file->f_mapping;
407
408 if (vma->vm_flags & VM_DENYWRITE)
409 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
410 if (vma->vm_flags & VM_SHARED)
411 mapping->i_mmap_writable++;
412
413 flush_dcache_mmap_lock(mapping);
414 if (unlikely(vma->vm_flags & VM_NONLINEAR))
415 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
416 else
417 vma_prio_tree_insert(vma, &mapping->i_mmap);
418 flush_dcache_mmap_unlock(mapping);
419 }
420}
421
422static void
423__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
424 struct vm_area_struct *prev, struct rb_node **rb_link,
425 struct rb_node *rb_parent)
426{
427 __vma_link_list(mm, vma, prev, rb_parent);
428 __vma_link_rb(mm, vma, rb_link, rb_parent);
429}
430
431static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
432 struct vm_area_struct *prev, struct rb_node **rb_link,
433 struct rb_node *rb_parent)
434{
435 struct address_space *mapping = NULL;
436
437 if (vma->vm_file)
438 mapping = vma->vm_file->f_mapping;
439
440 if (mapping)
441 mutex_lock(&mapping->i_mmap_mutex);
442
443 __vma_link(mm, vma, prev, rb_link, rb_parent);
444 __vma_link_file(vma);
445
446 if (mapping)
447 mutex_unlock(&mapping->i_mmap_mutex);
448
449 mm->map_count++;
450 validate_mm(mm);
451}
452
453/*
454 * Helper for vma_adjust in the split_vma insert case:
455 * insert vm structure into list and rbtree and anon_vma,
456 * but it has already been inserted into prio_tree earlier.
457 */
458static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
459{
460 struct vm_area_struct *__vma, *prev;
461 struct rb_node **rb_link, *rb_parent;
462
463 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
464 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
465 __vma_link(mm, vma, prev, rb_link, rb_parent);
466 mm->map_count++;
467}
468
469static inline void
470__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
471 struct vm_area_struct *prev)
472{
473 struct vm_area_struct *next = vma->vm_next;
474
475 prev->vm_next = next;
476 if (next)
477 next->vm_prev = prev;
478 rb_erase(&vma->vm_rb, &mm->mm_rb);
479 if (mm->mmap_cache == vma)
480 mm->mmap_cache = prev;
481}
482
483/*
484 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
485 * is already present in an i_mmap tree without adjusting the tree.
486 * The following helper function should be used when such adjustments
487 * are necessary. The "insert" vma (if any) is to be inserted
488 * before we drop the necessary locks.
489 */
490int vma_adjust(struct vm_area_struct *vma, unsigned long start,
491 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
492{
493 struct mm_struct *mm = vma->vm_mm;
494 struct vm_area_struct *next = vma->vm_next;
495 struct vm_area_struct *importer = NULL;
496 struct address_space *mapping = NULL;
497 struct prio_tree_root *root = NULL;
498 struct anon_vma *anon_vma = NULL;
499 struct file *file = vma->vm_file;
500 long adjust_next = 0;
501 int remove_next = 0;
502
503 if (next && !insert) {
504 struct vm_area_struct *exporter = NULL;
505
506 if (end >= next->vm_end) {
507 /*
508 * vma expands, overlapping all the next, and
509 * perhaps the one after too (mprotect case 6).
510 */
511again: remove_next = 1 + (end > next->vm_end);
512 end = next->vm_end;
513 exporter = next;
514 importer = vma;
515 } else if (end > next->vm_start) {
516 /*
517 * vma expands, overlapping part of the next:
518 * mprotect case 5 shifting the boundary up.
519 */
520 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
521 exporter = next;
522 importer = vma;
523 } else if (end < vma->vm_end) {
524 /*
525 * vma shrinks, and !insert tells it's not
526 * split_vma inserting another: so it must be
527 * mprotect case 4 shifting the boundary down.
528 */
529 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
530 exporter = vma;
531 importer = next;
532 }
533
534 /*
535 * Easily overlooked: when mprotect shifts the boundary,
536 * make sure the expanding vma has anon_vma set if the
537 * shrinking vma had, to cover any anon pages imported.
538 */
539 if (exporter && exporter->anon_vma && !importer->anon_vma) {
540 if (anon_vma_clone(importer, exporter))
541 return -ENOMEM;
542 importer->anon_vma = exporter->anon_vma;
543 }
544 }
545
546 if (file) {
547 mapping = file->f_mapping;
548 if (!(vma->vm_flags & VM_NONLINEAR))
549 root = &mapping->i_mmap;
550 mutex_lock(&mapping->i_mmap_mutex);
551 if (insert) {
552 /*
553 * Put into prio_tree now, so instantiated pages
554 * are visible to arm/parisc __flush_dcache_page
555 * throughout; but we cannot insert into address
556 * space until vma start or end is updated.
557 */
558 __vma_link_file(insert);
559 }
560 }
561
562 vma_adjust_trans_huge(vma, start, end, adjust_next);
563
564 /*
565 * When changing only vma->vm_end, we don't really need anon_vma
566 * lock. This is a fairly rare case by itself, but the anon_vma
567 * lock may be shared between many sibling processes. Skipping
568 * the lock for brk adjustments makes a difference sometimes.
569 */
570 if (vma->anon_vma && (importer || start != vma->vm_start)) {
571 anon_vma = vma->anon_vma;
572 anon_vma_lock(anon_vma);
573 }
574
575 if (root) {
576 flush_dcache_mmap_lock(mapping);
577 vma_prio_tree_remove(vma, root);
578 if (adjust_next)
579 vma_prio_tree_remove(next, root);
580 }
581
582 vma->vm_start = start;
583 vma->vm_end = end;
584 vma->vm_pgoff = pgoff;
585 if (adjust_next) {
586 next->vm_start += adjust_next << PAGE_SHIFT;
587 next->vm_pgoff += adjust_next;
588 }
589
590 if (root) {
591 if (adjust_next)
592 vma_prio_tree_insert(next, root);
593 vma_prio_tree_insert(vma, root);
594 flush_dcache_mmap_unlock(mapping);
595 }
596
597 if (remove_next) {
598 /*
599 * vma_merge has merged next into vma, and needs
600 * us to remove next before dropping the locks.
601 */
602 __vma_unlink(mm, next, vma);
603 if (file)
604 __remove_shared_vm_struct(next, file, mapping);
605 } else if (insert) {
606 /*
607 * split_vma has split insert from vma, and needs
608 * us to insert it before dropping the locks
609 * (it may either follow vma or precede it).
610 */
611 __insert_vm_struct(mm, insert);
612 }
613
614 if (anon_vma)
615 anon_vma_unlock(anon_vma);
616 if (mapping)
617 mutex_unlock(&mapping->i_mmap_mutex);
618
619 if (remove_next) {
620 if (file) {
621 fput(file);
622 if (next->vm_flags & VM_EXECUTABLE)
623 removed_exe_file_vma(mm);
624 }
625 if (next->anon_vma)
626 anon_vma_merge(vma, next);
627 mm->map_count--;
628 mpol_put(vma_policy(next));
629 kmem_cache_free(vm_area_cachep, next);
630 /*
631 * In mprotect's case 6 (see comments on vma_merge),
632 * we must remove another next too. It would clutter
633 * up the code too much to do both in one go.
634 */
635 if (remove_next == 2) {
636 next = vma->vm_next;
637 goto again;
638 }
639 }
640
641 validate_mm(mm);
642
643 return 0;
644}
645
646/*
647 * If the vma has a ->close operation then the driver probably needs to release
648 * per-vma resources, so we don't attempt to merge those.
649 */
650static inline int is_mergeable_vma(struct vm_area_struct *vma,
651 struct file *file, unsigned long vm_flags)
652{
653 /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
654 if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
655 return 0;
656 if (vma->vm_file != file)
657 return 0;
658 if (vma->vm_ops && vma->vm_ops->close)
659 return 0;
660 return 1;
661}
662
663static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
664 struct anon_vma *anon_vma2,
665 struct vm_area_struct *vma)
666{
667 /*
668 * The list_is_singular() test is to avoid merging VMA cloned from
669 * parents. This can improve scalability caused by anon_vma lock.
670 */
671 if ((!anon_vma1 || !anon_vma2) && (!vma ||
672 list_is_singular(&vma->anon_vma_chain)))
673 return 1;
674 return anon_vma1 == anon_vma2;
675}
676
677/*
678 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
679 * in front of (at a lower virtual address and file offset than) the vma.
680 *
681 * We cannot merge two vmas if they have differently assigned (non-NULL)
682 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
683 *
684 * We don't check here for the merged mmap wrapping around the end of pagecache
685 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
686 * wrap, nor mmaps which cover the final page at index -1UL.
687 */
688static int
689can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
690 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
691{
692 if (is_mergeable_vma(vma, file, vm_flags) &&
693 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
694 if (vma->vm_pgoff == vm_pgoff)
695 return 1;
696 }
697 return 0;
698}
699
700/*
701 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
702 * beyond (at a higher virtual address and file offset than) the vma.
703 *
704 * We cannot merge two vmas if they have differently assigned (non-NULL)
705 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
706 */
707static int
708can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
709 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
710{
711 if (is_mergeable_vma(vma, file, vm_flags) &&
712 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
713 pgoff_t vm_pglen;
714 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
715 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
716 return 1;
717 }
718 return 0;
719}
720
721/*
722 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
723 * whether that can be merged with its predecessor or its successor.
724 * Or both (it neatly fills a hole).
725 *
726 * In most cases - when called for mmap, brk or mremap - [addr,end) is
727 * certain not to be mapped by the time vma_merge is called; but when
728 * called for mprotect, it is certain to be already mapped (either at
729 * an offset within prev, or at the start of next), and the flags of
730 * this area are about to be changed to vm_flags - and the no-change
731 * case has already been eliminated.
732 *
733 * The following mprotect cases have to be considered, where AAAA is
734 * the area passed down from mprotect_fixup, never extending beyond one
735 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
736 *
737 * AAAA AAAA AAAA AAAA
738 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
739 * cannot merge might become might become might become
740 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
741 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
742 * mremap move: PPPPNNNNNNNN 8
743 * AAAA
744 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
745 * might become case 1 below case 2 below case 3 below
746 *
747 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
748 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
749 */
750struct vm_area_struct *vma_merge(struct mm_struct *mm,
751 struct vm_area_struct *prev, unsigned long addr,
752 unsigned long end, unsigned long vm_flags,
753 struct anon_vma *anon_vma, struct file *file,
754 pgoff_t pgoff, struct mempolicy *policy)
755{
756 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
757 struct vm_area_struct *area, *next;
758 int err;
759
760 /*
761 * We later require that vma->vm_flags == vm_flags,
762 * so this tests vma->vm_flags & VM_SPECIAL, too.
763 */
764 if (vm_flags & VM_SPECIAL)
765 return NULL;
766
767 if (prev)
768 next = prev->vm_next;
769 else
770 next = mm->mmap;
771 area = next;
772 if (next && next->vm_end == end) /* cases 6, 7, 8 */
773 next = next->vm_next;
774
775 /*
776 * Can it merge with the predecessor?
777 */
778 if (prev && prev->vm_end == addr &&
779 mpol_equal(vma_policy(prev), policy) &&
780 can_vma_merge_after(prev, vm_flags,
781 anon_vma, file, pgoff)) {
782 /*
783 * OK, it can. Can we now merge in the successor as well?
784 */
785 if (next && end == next->vm_start &&
786 mpol_equal(policy, vma_policy(next)) &&
787 can_vma_merge_before(next, vm_flags,
788 anon_vma, file, pgoff+pglen) &&
789 is_mergeable_anon_vma(prev->anon_vma,
790 next->anon_vma, NULL)) {
791 /* cases 1, 6 */
792 err = vma_adjust(prev, prev->vm_start,
793 next->vm_end, prev->vm_pgoff, NULL);
794 } else /* cases 2, 5, 7 */
795 err = vma_adjust(prev, prev->vm_start,
796 end, prev->vm_pgoff, NULL);
797 if (err)
798 return NULL;
799 khugepaged_enter_vma_merge(prev);
800 return prev;
801 }
802
803 /*
804 * Can this new request be merged in front of next?
805 */
806 if (next && end == next->vm_start &&
807 mpol_equal(policy, vma_policy(next)) &&
808 can_vma_merge_before(next, vm_flags,
809 anon_vma, file, pgoff+pglen)) {
810 if (prev && addr < prev->vm_end) /* case 4 */
811 err = vma_adjust(prev, prev->vm_start,
812 addr, prev->vm_pgoff, NULL);
813 else /* cases 3, 8 */
814 err = vma_adjust(area, addr, next->vm_end,
815 next->vm_pgoff - pglen, NULL);
816 if (err)
817 return NULL;
818 khugepaged_enter_vma_merge(area);
819 return area;
820 }
821
822 return NULL;
823}
824
825/*
826 * Rough compatbility check to quickly see if it's even worth looking
827 * at sharing an anon_vma.
828 *
829 * They need to have the same vm_file, and the flags can only differ
830 * in things that mprotect may change.
831 *
832 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
833 * we can merge the two vma's. For example, we refuse to merge a vma if
834 * there is a vm_ops->close() function, because that indicates that the
835 * driver is doing some kind of reference counting. But that doesn't
836 * really matter for the anon_vma sharing case.
837 */
838static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
839{
840 return a->vm_end == b->vm_start &&
841 mpol_equal(vma_policy(a), vma_policy(b)) &&
842 a->vm_file == b->vm_file &&
843 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
844 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
845}
846
847/*
848 * Do some basic sanity checking to see if we can re-use the anon_vma
849 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
850 * the same as 'old', the other will be the new one that is trying
851 * to share the anon_vma.
852 *
853 * NOTE! This runs with mm_sem held for reading, so it is possible that
854 * the anon_vma of 'old' is concurrently in the process of being set up
855 * by another page fault trying to merge _that_. But that's ok: if it
856 * is being set up, that automatically means that it will be a singleton
857 * acceptable for merging, so we can do all of this optimistically. But
858 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
859 *
860 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
861 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
862 * is to return an anon_vma that is "complex" due to having gone through
863 * a fork).
864 *
865 * We also make sure that the two vma's are compatible (adjacent,
866 * and with the same memory policies). That's all stable, even with just
867 * a read lock on the mm_sem.
868 */
869static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
870{
871 if (anon_vma_compatible(a, b)) {
872 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
873
874 if (anon_vma && list_is_singular(&old->anon_vma_chain))
875 return anon_vma;
876 }
877 return NULL;
878}
879
880/*
881 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
882 * neighbouring vmas for a suitable anon_vma, before it goes off
883 * to allocate a new anon_vma. It checks because a repetitive
884 * sequence of mprotects and faults may otherwise lead to distinct
885 * anon_vmas being allocated, preventing vma merge in subsequent
886 * mprotect.
887 */
888struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
889{
890 struct anon_vma *anon_vma;
891 struct vm_area_struct *near;
892
893 near = vma->vm_next;
894 if (!near)
895 goto try_prev;
896
897 anon_vma = reusable_anon_vma(near, vma, near);
898 if (anon_vma)
899 return anon_vma;
900try_prev:
901 near = vma->vm_prev;
902 if (!near)
903 goto none;
904
905 anon_vma = reusable_anon_vma(near, near, vma);
906 if (anon_vma)
907 return anon_vma;
908none:
909 /*
910 * There's no absolute need to look only at touching neighbours:
911 * we could search further afield for "compatible" anon_vmas.
912 * But it would probably just be a waste of time searching,
913 * or lead to too many vmas hanging off the same anon_vma.
914 * We're trying to allow mprotect remerging later on,
915 * not trying to minimize memory used for anon_vmas.
916 */
917 return NULL;
918}
919
920#ifdef CONFIG_PROC_FS
921void vm_stat_account(struct mm_struct *mm, unsigned long flags,
922 struct file *file, long pages)
923{
924 const unsigned long stack_flags
925 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
926
927 if (file) {
928 mm->shared_vm += pages;
929 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
930 mm->exec_vm += pages;
931 } else if (flags & stack_flags)
932 mm->stack_vm += pages;
933 if (flags & (VM_RESERVED|VM_IO))
934 mm->reserved_vm += pages;
935}
936#endif /* CONFIG_PROC_FS */
937
938/*
939 * The caller must hold down_write(¤t->mm->mmap_sem).
940 */
941
942unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
943 unsigned long len, unsigned long prot,
944 unsigned long flags, unsigned long pgoff)
945{
946 struct mm_struct * mm = current->mm;
947 struct inode *inode;
948 vm_flags_t vm_flags;
949 int error;
950 unsigned long reqprot = prot;
951
952 /*
953 * Does the application expect PROT_READ to imply PROT_EXEC?
954 *
955 * (the exception is when the underlying filesystem is noexec
956 * mounted, in which case we dont add PROT_EXEC.)
957 */
958 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
959 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
960 prot |= PROT_EXEC;
961
962 if (!len)
963 return -EINVAL;
964
965 if (!(flags & MAP_FIXED))
966 addr = round_hint_to_min(addr);
967
968 /* Careful about overflows.. */
969 len = PAGE_ALIGN(len);
970 if (!len)
971 return -ENOMEM;
972
973 /* offset overflow? */
974 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
975 return -EOVERFLOW;
976
977 /* Too many mappings? */
978 if (mm->map_count > sysctl_max_map_count)
979 return -ENOMEM;
980
981 /* Obtain the address to map to. we verify (or select) it and ensure
982 * that it represents a valid section of the address space.
983 */
984 addr = get_unmapped_area(file, addr, len, pgoff, flags);
985 if (addr & ~PAGE_MASK)
986 return addr;
987
988 /* Do simple checking here so the lower-level routines won't have
989 * to. we assume access permissions have been handled by the open
990 * of the memory object, so we don't do any here.
991 */
992 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
993 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
994
995 if (flags & MAP_LOCKED)
996 if (!can_do_mlock())
997 return -EPERM;
998
999 /* mlock MCL_FUTURE? */
1000 if (vm_flags & VM_LOCKED) {
1001 unsigned long locked, lock_limit;
1002 locked = len >> PAGE_SHIFT;
1003 locked += mm->locked_vm;
1004 lock_limit = rlimit(RLIMIT_MEMLOCK);
1005 lock_limit >>= PAGE_SHIFT;
1006 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1007 return -EAGAIN;
1008 }
1009
1010 inode = file ? file->f_path.dentry->d_inode : NULL;
1011
1012 if (file) {
1013 switch (flags & MAP_TYPE) {
1014 case MAP_SHARED:
1015 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1016 return -EACCES;
1017
1018 /*
1019 * Make sure we don't allow writing to an append-only
1020 * file..
1021 */
1022 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1023 return -EACCES;
1024
1025 /*
1026 * Make sure there are no mandatory locks on the file.
1027 */
1028 if (locks_verify_locked(inode))
1029 return -EAGAIN;
1030
1031 vm_flags |= VM_SHARED | VM_MAYSHARE;
1032 if (!(file->f_mode & FMODE_WRITE))
1033 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1034
1035 /* fall through */
1036 case MAP_PRIVATE:
1037 if (!(file->f_mode & FMODE_READ))
1038 return -EACCES;
1039 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
1040 if (vm_flags & VM_EXEC)
1041 return -EPERM;
1042 vm_flags &= ~VM_MAYEXEC;
1043 }
1044
1045 if (!file->f_op || !file->f_op->mmap)
1046 return -ENODEV;
1047 break;
1048
1049 default:
1050 return -EINVAL;
1051 }
1052 } else {
1053 switch (flags & MAP_TYPE) {
1054 case MAP_SHARED:
1055 /*
1056 * Ignore pgoff.
1057 */
1058 pgoff = 0;
1059 vm_flags |= VM_SHARED | VM_MAYSHARE;
1060 break;
1061 case MAP_PRIVATE:
1062 /*
1063 * Set pgoff according to addr for anon_vma.
1064 */
1065 pgoff = addr >> PAGE_SHIFT;
1066 break;
1067 default:
1068 return -EINVAL;
1069 }
1070 }
1071
1072 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
1073 if (error)
1074 return error;
1075
1076 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
1077}
1078EXPORT_SYMBOL(do_mmap_pgoff);
1079
1080SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1081 unsigned long, prot, unsigned long, flags,
1082 unsigned long, fd, unsigned long, pgoff)
1083{
1084 struct file *file = NULL;
1085 unsigned long retval = -EBADF;
1086
1087 if (!(flags & MAP_ANONYMOUS)) {
1088 audit_mmap_fd(fd, flags);
1089 if (unlikely(flags & MAP_HUGETLB))
1090 return -EINVAL;
1091 file = fget(fd);
1092 if (!file)
1093 goto out;
1094 } else if (flags & MAP_HUGETLB) {
1095 struct user_struct *user = NULL;
1096 /*
1097 * VM_NORESERVE is used because the reservations will be
1098 * taken when vm_ops->mmap() is called
1099 * A dummy user value is used because we are not locking
1100 * memory so no accounting is necessary
1101 */
1102 len = ALIGN(len, huge_page_size(&default_hstate));
1103 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
1104 &user, HUGETLB_ANONHUGE_INODE);
1105 if (IS_ERR(file))
1106 return PTR_ERR(file);
1107 }
1108
1109 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1110
1111 down_write(¤t->mm->mmap_sem);
1112 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1113 up_write(¤t->mm->mmap_sem);
1114
1115 if (file)
1116 fput(file);
1117out:
1118 return retval;
1119}
1120
1121#ifdef __ARCH_WANT_SYS_OLD_MMAP
1122struct mmap_arg_struct {
1123 unsigned long addr;
1124 unsigned long len;
1125 unsigned long prot;
1126 unsigned long flags;
1127 unsigned long fd;
1128 unsigned long offset;
1129};
1130
1131SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1132{
1133 struct mmap_arg_struct a;
1134
1135 if (copy_from_user(&a, arg, sizeof(a)))
1136 return -EFAULT;
1137 if (a.offset & ~PAGE_MASK)
1138 return -EINVAL;
1139
1140 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1141 a.offset >> PAGE_SHIFT);
1142}
1143#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1144
1145/*
1146 * Some shared mappigns will want the pages marked read-only
1147 * to track write events. If so, we'll downgrade vm_page_prot
1148 * to the private version (using protection_map[] without the
1149 * VM_SHARED bit).
1150 */
1151int vma_wants_writenotify(struct vm_area_struct *vma)
1152{
1153 vm_flags_t vm_flags = vma->vm_flags;
1154
1155 /* If it was private or non-writable, the write bit is already clear */
1156 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1157 return 0;
1158
1159 /* The backer wishes to know when pages are first written to? */
1160 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1161 return 1;
1162
1163 /* The open routine did something to the protections already? */
1164 if (pgprot_val(vma->vm_page_prot) !=
1165 pgprot_val(vm_get_page_prot(vm_flags)))
1166 return 0;
1167
1168 /* Specialty mapping? */
1169 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1170 return 0;
1171
1172 /* Can the mapping track the dirty pages? */
1173 return vma->vm_file && vma->vm_file->f_mapping &&
1174 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1175}
1176
1177/*
1178 * We account for memory if it's a private writeable mapping,
1179 * not hugepages and VM_NORESERVE wasn't set.
1180 */
1181static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
1182{
1183 /*
1184 * hugetlb has its own accounting separate from the core VM
1185 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1186 */
1187 if (file && is_file_hugepages(file))
1188 return 0;
1189
1190 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1191}
1192
1193unsigned long mmap_region(struct file *file, unsigned long addr,
1194 unsigned long len, unsigned long flags,
1195 vm_flags_t vm_flags, unsigned long pgoff)
1196{
1197 struct mm_struct *mm = current->mm;
1198 struct vm_area_struct *vma, *prev;
1199 int correct_wcount = 0;
1200 int error;
1201 struct rb_node **rb_link, *rb_parent;
1202 unsigned long charged = 0;
1203 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1204
1205 /* Clear old maps */
1206 error = -ENOMEM;
1207munmap_back:
1208 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1209 if (vma && vma->vm_start < addr + len) {
1210 if (do_munmap(mm, addr, len))
1211 return -ENOMEM;
1212 goto munmap_back;
1213 }
1214
1215 /* Check against address space limit. */
1216 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
1217 return -ENOMEM;
1218
1219 /*
1220 * Set 'VM_NORESERVE' if we should not account for the
1221 * memory use of this mapping.
1222 */
1223 if ((flags & MAP_NORESERVE)) {
1224 /* We honor MAP_NORESERVE if allowed to overcommit */
1225 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1226 vm_flags |= VM_NORESERVE;
1227
1228 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1229 if (file && is_file_hugepages(file))
1230 vm_flags |= VM_NORESERVE;
1231 }
1232
1233 /*
1234 * Private writable mapping: check memory availability
1235 */
1236 if (accountable_mapping(file, vm_flags)) {
1237 charged = len >> PAGE_SHIFT;
1238 if (security_vm_enough_memory(charged))
1239 return -ENOMEM;
1240 vm_flags |= VM_ACCOUNT;
1241 }
1242
1243 /*
1244 * Can we just expand an old mapping?
1245 */
1246 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1247 if (vma)
1248 goto out;
1249
1250 /*
1251 * Determine the object being mapped and call the appropriate
1252 * specific mapper. the address has already been validated, but
1253 * not unmapped, but the maps are removed from the list.
1254 */
1255 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1256 if (!vma) {
1257 error = -ENOMEM;
1258 goto unacct_error;
1259 }
1260
1261 vma->vm_mm = mm;
1262 vma->vm_start = addr;
1263 vma->vm_end = addr + len;
1264 vma->vm_flags = vm_flags;
1265 vma->vm_page_prot = vm_get_page_prot(vm_flags);
1266 vma->vm_pgoff = pgoff;
1267 INIT_LIST_HEAD(&vma->anon_vma_chain);
1268
1269 if (file) {
1270 error = -EINVAL;
1271 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1272 goto free_vma;
1273 if (vm_flags & VM_DENYWRITE) {
1274 error = deny_write_access(file);
1275 if (error)
1276 goto free_vma;
1277 correct_wcount = 1;
1278 }
1279 vma->vm_file = file;
1280 get_file(file);
1281 error = file->f_op->mmap(file, vma);
1282 if (error)
1283 goto unmap_and_free_vma;
1284 if (vm_flags & VM_EXECUTABLE)
1285 added_exe_file_vma(mm);
1286
1287 /* Can addr have changed??
1288 *
1289 * Answer: Yes, several device drivers can do it in their
1290 * f_op->mmap method. -DaveM
1291 */
1292 addr = vma->vm_start;
1293 pgoff = vma->vm_pgoff;
1294 vm_flags = vma->vm_flags;
1295 } else if (vm_flags & VM_SHARED) {
1296 error = shmem_zero_setup(vma);
1297 if (error)
1298 goto free_vma;
1299 }
1300
1301 if (vma_wants_writenotify(vma)) {
1302 pgprot_t pprot = vma->vm_page_prot;
1303
1304 /* Can vma->vm_page_prot have changed??
1305 *
1306 * Answer: Yes, drivers may have changed it in their
1307 * f_op->mmap method.
1308 *
1309 * Ensures that vmas marked as uncached stay that way.
1310 */
1311 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
1312 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1313 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1314 }
1315
1316 vma_link(mm, vma, prev, rb_link, rb_parent);
1317 file = vma->vm_file;
1318
1319 /* Once vma denies write, undo our temporary denial count */
1320 if (correct_wcount)
1321 atomic_inc(&inode->i_writecount);
1322out:
1323 perf_event_mmap(vma);
1324
1325 mm->total_vm += len >> PAGE_SHIFT;
1326 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
1327 if (vm_flags & VM_LOCKED) {
1328 if (!mlock_vma_pages_range(vma, addr, addr + len))
1329 mm->locked_vm += (len >> PAGE_SHIFT);
1330 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1331 make_pages_present(addr, addr + len);
1332 return addr;
1333
1334unmap_and_free_vma:
1335 if (correct_wcount)
1336 atomic_inc(&inode->i_writecount);
1337 vma->vm_file = NULL;
1338 fput(file);
1339
1340 /* Undo any partial mapping done by a device driver. */
1341 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1342 charged = 0;
1343free_vma:
1344 kmem_cache_free(vm_area_cachep, vma);
1345unacct_error:
1346 if (charged)
1347 vm_unacct_memory(charged);
1348 return error;
1349}
1350
1351/* Get an address range which is currently unmapped.
1352 * For shmat() with addr=0.
1353 *
1354 * Ugly calling convention alert:
1355 * Return value with the low bits set means error value,
1356 * ie
1357 * if (ret & ~PAGE_MASK)
1358 * error = ret;
1359 *
1360 * This function "knows" that -ENOMEM has the bits set.
1361 */
1362#ifndef HAVE_ARCH_UNMAPPED_AREA
1363unsigned long
1364arch_get_unmapped_area(struct file *filp, unsigned long addr,
1365 unsigned long len, unsigned long pgoff, unsigned long flags)
1366{
1367 struct mm_struct *mm = current->mm;
1368 struct vm_area_struct *vma;
1369 unsigned long start_addr;
1370
1371 if (len > TASK_SIZE)
1372 return -ENOMEM;
1373
1374 if (flags & MAP_FIXED)
1375 return addr;
1376
1377 if (addr) {
1378 addr = PAGE_ALIGN(addr);
1379 vma = find_vma(mm, addr);
1380 if (TASK_SIZE - len >= addr &&
1381 (!vma || addr + len <= vma->vm_start))
1382 return addr;
1383 }
1384 if (len > mm->cached_hole_size) {
1385 start_addr = addr = mm->free_area_cache;
1386 } else {
1387 start_addr = addr = TASK_UNMAPPED_BASE;
1388 mm->cached_hole_size = 0;
1389 }
1390
1391full_search:
1392 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1393 /* At this point: (!vma || addr < vma->vm_end). */
1394 if (TASK_SIZE - len < addr) {
1395 /*
1396 * Start a new search - just in case we missed
1397 * some holes.
1398 */
1399 if (start_addr != TASK_UNMAPPED_BASE) {
1400 addr = TASK_UNMAPPED_BASE;
1401 start_addr = addr;
1402 mm->cached_hole_size = 0;
1403 goto full_search;
1404 }
1405 return -ENOMEM;
1406 }
1407 if (!vma || addr + len <= vma->vm_start) {
1408 /*
1409 * Remember the place where we stopped the search:
1410 */
1411 mm->free_area_cache = addr + len;
1412 return addr;
1413 }
1414 if (addr + mm->cached_hole_size < vma->vm_start)
1415 mm->cached_hole_size = vma->vm_start - addr;
1416 addr = vma->vm_end;
1417 }
1418}
1419#endif
1420
1421void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1422{
1423 /*
1424 * Is this a new hole at the lowest possible address?
1425 */
1426 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1427 mm->free_area_cache = addr;
1428 mm->cached_hole_size = ~0UL;
1429 }
1430}
1431
1432/*
1433 * This mmap-allocator allocates new areas top-down from below the
1434 * stack's low limit (the base):
1435 */
1436#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1437unsigned long
1438arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1439 const unsigned long len, const unsigned long pgoff,
1440 const unsigned long flags)
1441{
1442 struct vm_area_struct *vma;
1443 struct mm_struct *mm = current->mm;
1444 unsigned long addr = addr0;
1445
1446 /* requested length too big for entire address space */
1447 if (len > TASK_SIZE)
1448 return -ENOMEM;
1449
1450 if (flags & MAP_FIXED)
1451 return addr;
1452
1453 /* requesting a specific address */
1454 if (addr) {
1455 addr = PAGE_ALIGN(addr);
1456 vma = find_vma(mm, addr);
1457 if (TASK_SIZE - len >= addr &&
1458 (!vma || addr + len <= vma->vm_start))
1459 return addr;
1460 }
1461
1462 /* check if free_area_cache is useful for us */
1463 if (len <= mm->cached_hole_size) {
1464 mm->cached_hole_size = 0;
1465 mm->free_area_cache = mm->mmap_base;
1466 }
1467
1468 /* either no address requested or can't fit in requested address hole */
1469 addr = mm->free_area_cache;
1470
1471 /* make sure it can fit in the remaining address space */
1472 if (addr > len) {
1473 vma = find_vma(mm, addr-len);
1474 if (!vma || addr <= vma->vm_start)
1475 /* remember the address as a hint for next time */
1476 return (mm->free_area_cache = addr-len);
1477 }
1478
1479 if (mm->mmap_base < len)
1480 goto bottomup;
1481
1482 addr = mm->mmap_base-len;
1483
1484 do {
1485 /*
1486 * Lookup failure means no vma is above this address,
1487 * else if new region fits below vma->vm_start,
1488 * return with success:
1489 */
1490 vma = find_vma(mm, addr);
1491 if (!vma || addr+len <= vma->vm_start)
1492 /* remember the address as a hint for next time */
1493 return (mm->free_area_cache = addr);
1494
1495 /* remember the largest hole we saw so far */
1496 if (addr + mm->cached_hole_size < vma->vm_start)
1497 mm->cached_hole_size = vma->vm_start - addr;
1498
1499 /* try just below the current vma->vm_start */
1500 addr = vma->vm_start-len;
1501 } while (len < vma->vm_start);
1502
1503bottomup:
1504 /*
1505 * A failed mmap() very likely causes application failure,
1506 * so fall back to the bottom-up function here. This scenario
1507 * can happen with large stack limits and large mmap()
1508 * allocations.
1509 */
1510 mm->cached_hole_size = ~0UL;
1511 mm->free_area_cache = TASK_UNMAPPED_BASE;
1512 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1513 /*
1514 * Restore the topdown base:
1515 */
1516 mm->free_area_cache = mm->mmap_base;
1517 mm->cached_hole_size = ~0UL;
1518
1519 return addr;
1520}
1521#endif
1522
1523void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
1524{
1525 /*
1526 * Is this a new hole at the highest possible address?
1527 */
1528 if (addr > mm->free_area_cache)
1529 mm->free_area_cache = addr;
1530
1531 /* dont allow allocations above current base */
1532 if (mm->free_area_cache > mm->mmap_base)
1533 mm->free_area_cache = mm->mmap_base;
1534}
1535
1536unsigned long
1537get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1538 unsigned long pgoff, unsigned long flags)
1539{
1540 unsigned long (*get_area)(struct file *, unsigned long,
1541 unsigned long, unsigned long, unsigned long);
1542
1543 unsigned long error = arch_mmap_check(addr, len, flags);
1544 if (error)
1545 return error;
1546
1547 /* Careful about overflows.. */
1548 if (len > TASK_SIZE)
1549 return -ENOMEM;
1550
1551 get_area = current->mm->get_unmapped_area;
1552 if (file && file->f_op && file->f_op->get_unmapped_area)
1553 get_area = file->f_op->get_unmapped_area;
1554 addr = get_area(file, addr, len, pgoff, flags);
1555 if (IS_ERR_VALUE(addr))
1556 return addr;
1557
1558 if (addr > TASK_SIZE - len)
1559 return -ENOMEM;
1560 if (addr & ~PAGE_MASK)
1561 return -EINVAL;
1562
1563 return arch_rebalance_pgtables(addr, len);
1564}
1565
1566EXPORT_SYMBOL(get_unmapped_area);
1567
1568/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1569struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1570{
1571 struct vm_area_struct *vma = NULL;
1572
1573 if (mm) {
1574 /* Check the cache first. */
1575 /* (Cache hit rate is typically around 35%.) */
1576 vma = mm->mmap_cache;
1577 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1578 struct rb_node * rb_node;
1579
1580 rb_node = mm->mm_rb.rb_node;
1581 vma = NULL;
1582
1583 while (rb_node) {
1584 struct vm_area_struct * vma_tmp;
1585
1586 vma_tmp = rb_entry(rb_node,
1587 struct vm_area_struct, vm_rb);
1588
1589 if (vma_tmp->vm_end > addr) {
1590 vma = vma_tmp;
1591 if (vma_tmp->vm_start <= addr)
1592 break;
1593 rb_node = rb_node->rb_left;
1594 } else
1595 rb_node = rb_node->rb_right;
1596 }
1597 if (vma)
1598 mm->mmap_cache = vma;
1599 }
1600 }
1601 return vma;
1602}
1603
1604EXPORT_SYMBOL(find_vma);
1605
1606/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1607struct vm_area_struct *
1608find_vma_prev(struct mm_struct *mm, unsigned long addr,
1609 struct vm_area_struct **pprev)
1610{
1611 struct vm_area_struct *vma = NULL, *prev = NULL;
1612 struct rb_node *rb_node;
1613 if (!mm)
1614 goto out;
1615
1616 /* Guard against addr being lower than the first VMA */
1617 vma = mm->mmap;
1618
1619 /* Go through the RB tree quickly. */
1620 rb_node = mm->mm_rb.rb_node;
1621
1622 while (rb_node) {
1623 struct vm_area_struct *vma_tmp;
1624 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1625
1626 if (addr < vma_tmp->vm_end) {
1627 rb_node = rb_node->rb_left;
1628 } else {
1629 prev = vma_tmp;
1630 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1631 break;
1632 rb_node = rb_node->rb_right;
1633 }
1634 }
1635
1636out:
1637 *pprev = prev;
1638 return prev ? prev->vm_next : vma;
1639}
1640
1641/*
1642 * Verify that the stack growth is acceptable and
1643 * update accounting. This is shared with both the
1644 * grow-up and grow-down cases.
1645 */
1646static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
1647{
1648 struct mm_struct *mm = vma->vm_mm;
1649 struct rlimit *rlim = current->signal->rlim;
1650 unsigned long new_start;
1651
1652 /* address space limit tests */
1653 if (!may_expand_vm(mm, grow))
1654 return -ENOMEM;
1655
1656 /* Stack limit test */
1657 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
1658 return -ENOMEM;
1659
1660 /* mlock limit tests */
1661 if (vma->vm_flags & VM_LOCKED) {
1662 unsigned long locked;
1663 unsigned long limit;
1664 locked = mm->locked_vm + grow;
1665 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
1666 limit >>= PAGE_SHIFT;
1667 if (locked > limit && !capable(CAP_IPC_LOCK))
1668 return -ENOMEM;
1669 }
1670
1671 /* Check to ensure the stack will not grow into a hugetlb-only region */
1672 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1673 vma->vm_end - size;
1674 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1675 return -EFAULT;
1676
1677 /*
1678 * Overcommit.. This must be the final test, as it will
1679 * update security statistics.
1680 */
1681 if (security_vm_enough_memory_mm(mm, grow))
1682 return -ENOMEM;
1683
1684 /* Ok, everything looks good - let it rip */
1685 mm->total_vm += grow;
1686 if (vma->vm_flags & VM_LOCKED)
1687 mm->locked_vm += grow;
1688 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
1689 return 0;
1690}
1691
1692#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1693/*
1694 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1695 * vma is the last one with address > vma->vm_end. Have to extend vma.
1696 */
1697int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1698{
1699 int error;
1700
1701 if (!(vma->vm_flags & VM_GROWSUP))
1702 return -EFAULT;
1703
1704 /*
1705 * We must make sure the anon_vma is allocated
1706 * so that the anon_vma locking is not a noop.
1707 */
1708 if (unlikely(anon_vma_prepare(vma)))
1709 return -ENOMEM;
1710 vma_lock_anon_vma(vma);
1711
1712 /*
1713 * vma->vm_start/vm_end cannot change under us because the caller
1714 * is required to hold the mmap_sem in read mode. We need the
1715 * anon_vma lock to serialize against concurrent expand_stacks.
1716 * Also guard against wrapping around to address 0.
1717 */
1718 if (address < PAGE_ALIGN(address+4))
1719 address = PAGE_ALIGN(address+4);
1720 else {
1721 vma_unlock_anon_vma(vma);
1722 return -ENOMEM;
1723 }
1724 error = 0;
1725
1726 /* Somebody else might have raced and expanded it already */
1727 if (address > vma->vm_end) {
1728 unsigned long size, grow;
1729
1730 size = address - vma->vm_start;
1731 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1732
1733 error = -ENOMEM;
1734 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
1735 error = acct_stack_growth(vma, size, grow);
1736 if (!error) {
1737 vma->vm_end = address;
1738 perf_event_mmap(vma);
1739 }
1740 }
1741 }
1742 vma_unlock_anon_vma(vma);
1743 khugepaged_enter_vma_merge(vma);
1744 return error;
1745}
1746#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1747
1748/*
1749 * vma is the first one with address < vma->vm_start. Have to extend vma.
1750 */
1751int expand_downwards(struct vm_area_struct *vma,
1752 unsigned long address)
1753{
1754 int error;
1755
1756 /*
1757 * We must make sure the anon_vma is allocated
1758 * so that the anon_vma locking is not a noop.
1759 */
1760 if (unlikely(anon_vma_prepare(vma)))
1761 return -ENOMEM;
1762
1763 address &= PAGE_MASK;
1764 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
1765 if (error)
1766 return error;
1767
1768 vma_lock_anon_vma(vma);
1769
1770 /*
1771 * vma->vm_start/vm_end cannot change under us because the caller
1772 * is required to hold the mmap_sem in read mode. We need the
1773 * anon_vma lock to serialize against concurrent expand_stacks.
1774 */
1775
1776 /* Somebody else might have raced and expanded it already */
1777 if (address < vma->vm_start) {
1778 unsigned long size, grow;
1779
1780 size = vma->vm_end - address;
1781 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1782
1783 error = -ENOMEM;
1784 if (grow <= vma->vm_pgoff) {
1785 error = acct_stack_growth(vma, size, grow);
1786 if (!error) {
1787 vma->vm_start = address;
1788 vma->vm_pgoff -= grow;
1789 perf_event_mmap(vma);
1790 }
1791 }
1792 }
1793 vma_unlock_anon_vma(vma);
1794 khugepaged_enter_vma_merge(vma);
1795 return error;
1796}
1797
1798#ifdef CONFIG_STACK_GROWSUP
1799int expand_stack(struct vm_area_struct *vma, unsigned long address)
1800{
1801 return expand_upwards(vma, address);
1802}
1803
1804struct vm_area_struct *
1805find_extend_vma(struct mm_struct *mm, unsigned long addr)
1806{
1807 struct vm_area_struct *vma, *prev;
1808
1809 addr &= PAGE_MASK;
1810 vma = find_vma_prev(mm, addr, &prev);
1811 if (vma && (vma->vm_start <= addr))
1812 return vma;
1813 if (!prev || expand_stack(prev, addr))
1814 return NULL;
1815 if (prev->vm_flags & VM_LOCKED) {
1816 mlock_vma_pages_range(prev, addr, prev->vm_end);
1817 }
1818 return prev;
1819}
1820#else
1821int expand_stack(struct vm_area_struct *vma, unsigned long address)
1822{
1823 return expand_downwards(vma, address);
1824}
1825
1826struct vm_area_struct *
1827find_extend_vma(struct mm_struct * mm, unsigned long addr)
1828{
1829 struct vm_area_struct * vma;
1830 unsigned long start;
1831
1832 addr &= PAGE_MASK;
1833 vma = find_vma(mm,addr);
1834 if (!vma)
1835 return NULL;
1836 if (vma->vm_start <= addr)
1837 return vma;
1838 if (!(vma->vm_flags & VM_GROWSDOWN))
1839 return NULL;
1840 start = vma->vm_start;
1841 if (expand_stack(vma, addr))
1842 return NULL;
1843 if (vma->vm_flags & VM_LOCKED) {
1844 mlock_vma_pages_range(vma, addr, start);
1845 }
1846 return vma;
1847}
1848#endif
1849
1850/*
1851 * Ok - we have the memory areas we should free on the vma list,
1852 * so release them, and do the vma updates.
1853 *
1854 * Called with the mm semaphore held.
1855 */
1856static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
1857{
1858 /* Update high watermark before we lower total_vm */
1859 update_hiwater_vm(mm);
1860 do {
1861 long nrpages = vma_pages(vma);
1862
1863 mm->total_vm -= nrpages;
1864 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
1865 vma = remove_vma(vma);
1866 } while (vma);
1867 validate_mm(mm);
1868}
1869
1870/*
1871 * Get rid of page table information in the indicated region.
1872 *
1873 * Called with the mm semaphore held.
1874 */
1875static void unmap_region(struct mm_struct *mm,
1876 struct vm_area_struct *vma, struct vm_area_struct *prev,
1877 unsigned long start, unsigned long end)
1878{
1879 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
1880 struct mmu_gather tlb;
1881 unsigned long nr_accounted = 0;
1882
1883 lru_add_drain();
1884 tlb_gather_mmu(&tlb, mm, 0);
1885 update_hiwater_rss(mm);
1886 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
1887 vm_unacct_memory(nr_accounted);
1888 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
1889 next ? next->vm_start : 0);
1890 tlb_finish_mmu(&tlb, start, end);
1891}
1892
1893/*
1894 * Create a list of vma's touched by the unmap, removing them from the mm's
1895 * vma list as we go..
1896 */
1897static void
1898detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1899 struct vm_area_struct *prev, unsigned long end)
1900{
1901 struct vm_area_struct **insertion_point;
1902 struct vm_area_struct *tail_vma = NULL;
1903 unsigned long addr;
1904
1905 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1906 vma->vm_prev = NULL;
1907 do {
1908 rb_erase(&vma->vm_rb, &mm->mm_rb);
1909 mm->map_count--;
1910 tail_vma = vma;
1911 vma = vma->vm_next;
1912 } while (vma && vma->vm_start < end);
1913 *insertion_point = vma;
1914 if (vma)
1915 vma->vm_prev = prev;
1916 tail_vma->vm_next = NULL;
1917 if (mm->unmap_area == arch_unmap_area)
1918 addr = prev ? prev->vm_end : mm->mmap_base;
1919 else
1920 addr = vma ? vma->vm_start : mm->mmap_base;
1921 mm->unmap_area(mm, addr);
1922 mm->mmap_cache = NULL; /* Kill the cache. */
1923}
1924
1925/*
1926 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
1927 * munmap path where it doesn't make sense to fail.
1928 */
1929static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1930 unsigned long addr, int new_below)
1931{
1932 struct mempolicy *pol;
1933 struct vm_area_struct *new;
1934 int err = -ENOMEM;
1935
1936 if (is_vm_hugetlb_page(vma) && (addr &
1937 ~(huge_page_mask(hstate_vma(vma)))))
1938 return -EINVAL;
1939
1940 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1941 if (!new)
1942 goto out_err;
1943
1944 /* most fields are the same, copy all, and then fixup */
1945 *new = *vma;
1946
1947 INIT_LIST_HEAD(&new->anon_vma_chain);
1948
1949 if (new_below)
1950 new->vm_end = addr;
1951 else {
1952 new->vm_start = addr;
1953 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1954 }
1955
1956 pol = mpol_dup(vma_policy(vma));
1957 if (IS_ERR(pol)) {
1958 err = PTR_ERR(pol);
1959 goto out_free_vma;
1960 }
1961 vma_set_policy(new, pol);
1962
1963 if (anon_vma_clone(new, vma))
1964 goto out_free_mpol;
1965
1966 if (new->vm_file) {
1967 get_file(new->vm_file);
1968 if (vma->vm_flags & VM_EXECUTABLE)
1969 added_exe_file_vma(mm);
1970 }
1971
1972 if (new->vm_ops && new->vm_ops->open)
1973 new->vm_ops->open(new);
1974
1975 if (new_below)
1976 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1977 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1978 else
1979 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1980
1981 /* Success. */
1982 if (!err)
1983 return 0;
1984
1985 /* Clean everything up if vma_adjust failed. */
1986 if (new->vm_ops && new->vm_ops->close)
1987 new->vm_ops->close(new);
1988 if (new->vm_file) {
1989 if (vma->vm_flags & VM_EXECUTABLE)
1990 removed_exe_file_vma(mm);
1991 fput(new->vm_file);
1992 }
1993 unlink_anon_vmas(new);
1994 out_free_mpol:
1995 mpol_put(pol);
1996 out_free_vma:
1997 kmem_cache_free(vm_area_cachep, new);
1998 out_err:
1999 return err;
2000}
2001
2002/*
2003 * Split a vma into two pieces at address 'addr', a new vma is allocated
2004 * either for the first part or the tail.
2005 */
2006int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2007 unsigned long addr, int new_below)
2008{
2009 if (mm->map_count >= sysctl_max_map_count)
2010 return -ENOMEM;
2011
2012 return __split_vma(mm, vma, addr, new_below);
2013}
2014
2015/* Munmap is split into 2 main parts -- this part which finds
2016 * what needs doing, and the areas themselves, which do the
2017 * work. This now handles partial unmappings.
2018 * Jeremy Fitzhardinge <jeremy@goop.org>
2019 */
2020int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2021{
2022 unsigned long end;
2023 struct vm_area_struct *vma, *prev, *last;
2024
2025 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2026 return -EINVAL;
2027
2028 if ((len = PAGE_ALIGN(len)) == 0)
2029 return -EINVAL;
2030
2031 /* Find the first overlapping VMA */
2032 vma = find_vma(mm, start);
2033 if (!vma)
2034 return 0;
2035 prev = vma->vm_prev;
2036 /* we have start < vma->vm_end */
2037
2038 /* if it doesn't overlap, we have nothing.. */
2039 end = start + len;
2040 if (vma->vm_start >= end)
2041 return 0;
2042
2043 /*
2044 * If we need to split any vma, do it now to save pain later.
2045 *
2046 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2047 * unmapped vm_area_struct will remain in use: so lower split_vma
2048 * places tmp vma above, and higher split_vma places tmp vma below.
2049 */
2050 if (start > vma->vm_start) {
2051 int error;
2052
2053 /*
2054 * Make sure that map_count on return from munmap() will
2055 * not exceed its limit; but let map_count go just above
2056 * its limit temporarily, to help free resources as expected.
2057 */
2058 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2059 return -ENOMEM;
2060
2061 error = __split_vma(mm, vma, start, 0);
2062 if (error)
2063 return error;
2064 prev = vma;
2065 }
2066
2067 /* Does it split the last one? */
2068 last = find_vma(mm, end);
2069 if (last && end > last->vm_start) {
2070 int error = __split_vma(mm, last, end, 1);
2071 if (error)
2072 return error;
2073 }
2074 vma = prev? prev->vm_next: mm->mmap;
2075
2076 /*
2077 * unlock any mlock()ed ranges before detaching vmas
2078 */
2079 if (mm->locked_vm) {
2080 struct vm_area_struct *tmp = vma;
2081 while (tmp && tmp->vm_start < end) {
2082 if (tmp->vm_flags & VM_LOCKED) {
2083 mm->locked_vm -= vma_pages(tmp);
2084 munlock_vma_pages_all(tmp);
2085 }
2086 tmp = tmp->vm_next;
2087 }
2088 }
2089
2090 /*
2091 * Remove the vma's, and unmap the actual pages
2092 */
2093 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2094 unmap_region(mm, vma, prev, start, end);
2095
2096 /* Fix up all other VM information */
2097 remove_vma_list(mm, vma);
2098
2099 return 0;
2100}
2101
2102EXPORT_SYMBOL(do_munmap);
2103
2104SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
2105{
2106 int ret;
2107 struct mm_struct *mm = current->mm;
2108
2109 profile_munmap(addr);
2110
2111 down_write(&mm->mmap_sem);
2112 ret = do_munmap(mm, addr, len);
2113 up_write(&mm->mmap_sem);
2114 return ret;
2115}
2116
2117static inline void verify_mm_writelocked(struct mm_struct *mm)
2118{
2119#ifdef CONFIG_DEBUG_VM
2120 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2121 WARN_ON(1);
2122 up_read(&mm->mmap_sem);
2123 }
2124#endif
2125}
2126
2127/*
2128 * this is really a simplified "do_mmap". it only handles
2129 * anonymous maps. eventually we may be able to do some
2130 * brk-specific accounting here.
2131 */
2132unsigned long do_brk(unsigned long addr, unsigned long len)
2133{
2134 struct mm_struct * mm = current->mm;
2135 struct vm_area_struct * vma, * prev;
2136 unsigned long flags;
2137 struct rb_node ** rb_link, * rb_parent;
2138 pgoff_t pgoff = addr >> PAGE_SHIFT;
2139 int error;
2140
2141 len = PAGE_ALIGN(len);
2142 if (!len)
2143 return addr;
2144
2145 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
2146 if (error)
2147 return error;
2148
2149 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2150
2151 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2152 if (error & ~PAGE_MASK)
2153 return error;
2154
2155 /*
2156 * mlock MCL_FUTURE?
2157 */
2158 if (mm->def_flags & VM_LOCKED) {
2159 unsigned long locked, lock_limit;
2160 locked = len >> PAGE_SHIFT;
2161 locked += mm->locked_vm;
2162 lock_limit = rlimit(RLIMIT_MEMLOCK);
2163 lock_limit >>= PAGE_SHIFT;
2164 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2165 return -EAGAIN;
2166 }
2167
2168 /*
2169 * mm->mmap_sem is required to protect against another thread
2170 * changing the mappings in case we sleep.
2171 */
2172 verify_mm_writelocked(mm);
2173
2174 /*
2175 * Clear old maps. this also does some error checking for us
2176 */
2177 munmap_back:
2178 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2179 if (vma && vma->vm_start < addr + len) {
2180 if (do_munmap(mm, addr, len))
2181 return -ENOMEM;
2182 goto munmap_back;
2183 }
2184
2185 /* Check against address space limits *after* clearing old maps... */
2186 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
2187 return -ENOMEM;
2188
2189 if (mm->map_count > sysctl_max_map_count)
2190 return -ENOMEM;
2191
2192 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2193 return -ENOMEM;
2194
2195 /* Can we just expand an old private anonymous mapping? */
2196 vma = vma_merge(mm, prev, addr, addr + len, flags,
2197 NULL, NULL, pgoff, NULL);
2198 if (vma)
2199 goto out;
2200
2201 /*
2202 * create a vma struct for an anonymous mapping
2203 */
2204 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2205 if (!vma) {
2206 vm_unacct_memory(len >> PAGE_SHIFT);
2207 return -ENOMEM;
2208 }
2209
2210 INIT_LIST_HEAD(&vma->anon_vma_chain);
2211 vma->vm_mm = mm;
2212 vma->vm_start = addr;
2213 vma->vm_end = addr + len;
2214 vma->vm_pgoff = pgoff;
2215 vma->vm_flags = flags;
2216 vma->vm_page_prot = vm_get_page_prot(flags);
2217 vma_link(mm, vma, prev, rb_link, rb_parent);
2218out:
2219 perf_event_mmap(vma);
2220 mm->total_vm += len >> PAGE_SHIFT;
2221 if (flags & VM_LOCKED) {
2222 if (!mlock_vma_pages_range(vma, addr, addr + len))
2223 mm->locked_vm += (len >> PAGE_SHIFT);
2224 }
2225 return addr;
2226}
2227
2228EXPORT_SYMBOL(do_brk);
2229
2230/* Release all mmaps. */
2231void exit_mmap(struct mm_struct *mm)
2232{
2233 struct mmu_gather tlb;
2234 struct vm_area_struct *vma;
2235 unsigned long nr_accounted = 0;
2236 unsigned long end;
2237
2238 /* mm's last user has gone, and its about to be pulled down */
2239 mmu_notifier_release(mm);
2240
2241 if (mm->locked_vm) {
2242 vma = mm->mmap;
2243 while (vma) {
2244 if (vma->vm_flags & VM_LOCKED)
2245 munlock_vma_pages_all(vma);
2246 vma = vma->vm_next;
2247 }
2248 }
2249
2250 arch_exit_mmap(mm);
2251
2252 vma = mm->mmap;
2253 if (!vma) /* Can happen if dup_mmap() received an OOM */
2254 return;
2255
2256 lru_add_drain();
2257 flush_cache_mm(mm);
2258 tlb_gather_mmu(&tlb, mm, 1);
2259 /* update_hiwater_rss(mm) here? but nobody should be looking */
2260 /* Use -1 here to ensure all VMAs in the mm are unmapped */
2261 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
2262 vm_unacct_memory(nr_accounted);
2263
2264 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
2265 tlb_finish_mmu(&tlb, 0, end);
2266
2267 /*
2268 * Walk the list again, actually closing and freeing it,
2269 * with preemption enabled, without holding any MM locks.
2270 */
2271 while (vma)
2272 vma = remove_vma(vma);
2273
2274 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
2275}
2276
2277/* Insert vm structure into process list sorted by address
2278 * and into the inode's i_mmap tree. If vm_file is non-NULL
2279 * then i_mmap_mutex is taken here.
2280 */
2281int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2282{
2283 struct vm_area_struct * __vma, * prev;
2284 struct rb_node ** rb_link, * rb_parent;
2285
2286 /*
2287 * The vm_pgoff of a purely anonymous vma should be irrelevant
2288 * until its first write fault, when page's anon_vma and index
2289 * are set. But now set the vm_pgoff it will almost certainly
2290 * end up with (unless mremap moves it elsewhere before that
2291 * first wfault), so /proc/pid/maps tells a consistent story.
2292 *
2293 * By setting it to reflect the virtual start address of the
2294 * vma, merges and splits can happen in a seamless way, just
2295 * using the existing file pgoff checks and manipulations.
2296 * Similarly in do_mmap_pgoff and in do_brk.
2297 */
2298 if (!vma->vm_file) {
2299 BUG_ON(vma->anon_vma);
2300 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2301 }
2302 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2303 if (__vma && __vma->vm_start < vma->vm_end)
2304 return -ENOMEM;
2305 if ((vma->vm_flags & VM_ACCOUNT) &&
2306 security_vm_enough_memory_mm(mm, vma_pages(vma)))
2307 return -ENOMEM;
2308 vma_link(mm, vma, prev, rb_link, rb_parent);
2309 return 0;
2310}
2311
2312/*
2313 * Copy the vma structure to a new location in the same mm,
2314 * prior to moving page table entries, to effect an mremap move.
2315 */
2316struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2317 unsigned long addr, unsigned long len, pgoff_t pgoff)
2318{
2319 struct vm_area_struct *vma = *vmap;
2320 unsigned long vma_start = vma->vm_start;
2321 struct mm_struct *mm = vma->vm_mm;
2322 struct vm_area_struct *new_vma, *prev;
2323 struct rb_node **rb_link, *rb_parent;
2324 struct mempolicy *pol;
2325
2326 /*
2327 * If anonymous vma has not yet been faulted, update new pgoff
2328 * to match new location, to increase its chance of merging.
2329 */
2330 if (!vma->vm_file && !vma->anon_vma)
2331 pgoff = addr >> PAGE_SHIFT;
2332
2333 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2334 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2335 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2336 if (new_vma) {
2337 /*
2338 * Source vma may have been merged into new_vma
2339 */
2340 if (vma_start >= new_vma->vm_start &&
2341 vma_start < new_vma->vm_end)
2342 *vmap = new_vma;
2343 } else {
2344 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
2345 if (new_vma) {
2346 *new_vma = *vma;
2347 pol = mpol_dup(vma_policy(vma));
2348 if (IS_ERR(pol))
2349 goto out_free_vma;
2350 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2351 if (anon_vma_clone(new_vma, vma))
2352 goto out_free_mempol;
2353 vma_set_policy(new_vma, pol);
2354 new_vma->vm_start = addr;
2355 new_vma->vm_end = addr + len;
2356 new_vma->vm_pgoff = pgoff;
2357 if (new_vma->vm_file) {
2358 get_file(new_vma->vm_file);
2359 if (vma->vm_flags & VM_EXECUTABLE)
2360 added_exe_file_vma(mm);
2361 }
2362 if (new_vma->vm_ops && new_vma->vm_ops->open)
2363 new_vma->vm_ops->open(new_vma);
2364 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2365 }
2366 }
2367 return new_vma;
2368
2369 out_free_mempol:
2370 mpol_put(pol);
2371 out_free_vma:
2372 kmem_cache_free(vm_area_cachep, new_vma);
2373 return NULL;
2374}
2375
2376/*
2377 * Return true if the calling process may expand its vm space by the passed
2378 * number of pages
2379 */
2380int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2381{
2382 unsigned long cur = mm->total_vm; /* pages */
2383 unsigned long lim;
2384
2385 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
2386
2387 if (cur + npages > lim)
2388 return 0;
2389 return 1;
2390}
2391
2392
2393static int special_mapping_fault(struct vm_area_struct *vma,
2394 struct vm_fault *vmf)
2395{
2396 pgoff_t pgoff;
2397 struct page **pages;
2398
2399 /*
2400 * special mappings have no vm_file, and in that case, the mm
2401 * uses vm_pgoff internally. So we have to subtract it from here.
2402 * We are allowed to do this because we are the mm; do not copy
2403 * this code into drivers!
2404 */
2405 pgoff = vmf->pgoff - vma->vm_pgoff;
2406
2407 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2408 pgoff--;
2409
2410 if (*pages) {
2411 struct page *page = *pages;
2412 get_page(page);
2413 vmf->page = page;
2414 return 0;
2415 }
2416
2417 return VM_FAULT_SIGBUS;
2418}
2419
2420/*
2421 * Having a close hook prevents vma merging regardless of flags.
2422 */
2423static void special_mapping_close(struct vm_area_struct *vma)
2424{
2425}
2426
2427static const struct vm_operations_struct special_mapping_vmops = {
2428 .close = special_mapping_close,
2429 .fault = special_mapping_fault,
2430};
2431
2432/*
2433 * Called with mm->mmap_sem held for writing.
2434 * Insert a new vma covering the given region, with the given flags.
2435 * Its pages are supplied by the given array of struct page *.
2436 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2437 * The region past the last page supplied will always produce SIGBUS.
2438 * The array pointer and the pages it points to are assumed to stay alive
2439 * for as long as this mapping might exist.
2440 */
2441int install_special_mapping(struct mm_struct *mm,
2442 unsigned long addr, unsigned long len,
2443 unsigned long vm_flags, struct page **pages)
2444{
2445 int ret;
2446 struct vm_area_struct *vma;
2447
2448 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2449 if (unlikely(vma == NULL))
2450 return -ENOMEM;
2451
2452 INIT_LIST_HEAD(&vma->anon_vma_chain);
2453 vma->vm_mm = mm;
2454 vma->vm_start = addr;
2455 vma->vm_end = addr + len;
2456
2457 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
2458 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
2459
2460 vma->vm_ops = &special_mapping_vmops;
2461 vma->vm_private_data = pages;
2462
2463 ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
2464 if (ret)
2465 goto out;
2466
2467 ret = insert_vm_struct(mm, vma);
2468 if (ret)
2469 goto out;
2470
2471 mm->total_vm += len >> PAGE_SHIFT;
2472
2473 perf_event_mmap(vma);
2474
2475 return 0;
2476
2477out:
2478 kmem_cache_free(vm_area_cachep, vma);
2479 return ret;
2480}
2481
2482static DEFINE_MUTEX(mm_all_locks_mutex);
2483
2484static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
2485{
2486 if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
2487 /*
2488 * The LSB of head.next can't change from under us
2489 * because we hold the mm_all_locks_mutex.
2490 */
2491 mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem);
2492 /*
2493 * We can safely modify head.next after taking the
2494 * anon_vma->root->mutex. If some other vma in this mm shares
2495 * the same anon_vma we won't take it again.
2496 *
2497 * No need of atomic instructions here, head.next
2498 * can't change from under us thanks to the
2499 * anon_vma->root->mutex.
2500 */
2501 if (__test_and_set_bit(0, (unsigned long *)
2502 &anon_vma->root->head.next))
2503 BUG();
2504 }
2505}
2506
2507static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
2508{
2509 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2510 /*
2511 * AS_MM_ALL_LOCKS can't change from under us because
2512 * we hold the mm_all_locks_mutex.
2513 *
2514 * Operations on ->flags have to be atomic because
2515 * even if AS_MM_ALL_LOCKS is stable thanks to the
2516 * mm_all_locks_mutex, there may be other cpus
2517 * changing other bitflags in parallel to us.
2518 */
2519 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2520 BUG();
2521 mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem);
2522 }
2523}
2524
2525/*
2526 * This operation locks against the VM for all pte/vma/mm related
2527 * operations that could ever happen on a certain mm. This includes
2528 * vmtruncate, try_to_unmap, and all page faults.
2529 *
2530 * The caller must take the mmap_sem in write mode before calling
2531 * mm_take_all_locks(). The caller isn't allowed to release the
2532 * mmap_sem until mm_drop_all_locks() returns.
2533 *
2534 * mmap_sem in write mode is required in order to block all operations
2535 * that could modify pagetables and free pages without need of
2536 * altering the vma layout (for example populate_range() with
2537 * nonlinear vmas). It's also needed in write mode to avoid new
2538 * anon_vmas to be associated with existing vmas.
2539 *
2540 * A single task can't take more than one mm_take_all_locks() in a row
2541 * or it would deadlock.
2542 *
2543 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2544 * mapping->flags avoid to take the same lock twice, if more than one
2545 * vma in this mm is backed by the same anon_vma or address_space.
2546 *
2547 * We can take all the locks in random order because the VM code
2548 * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never
2549 * takes more than one of them in a row. Secondly we're protected
2550 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2551 *
2552 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2553 * that may have to take thousand of locks.
2554 *
2555 * mm_take_all_locks() can fail if it's interrupted by signals.
2556 */
2557int mm_take_all_locks(struct mm_struct *mm)
2558{
2559 struct vm_area_struct *vma;
2560 struct anon_vma_chain *avc;
2561 int ret = -EINTR;
2562
2563 BUG_ON(down_read_trylock(&mm->mmap_sem));
2564
2565 mutex_lock(&mm_all_locks_mutex);
2566
2567 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2568 if (signal_pending(current))
2569 goto out_unlock;
2570 if (vma->vm_file && vma->vm_file->f_mapping)
2571 vm_lock_mapping(mm, vma->vm_file->f_mapping);
2572 }
2573
2574 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2575 if (signal_pending(current))
2576 goto out_unlock;
2577 if (vma->anon_vma)
2578 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2579 vm_lock_anon_vma(mm, avc->anon_vma);
2580 }
2581
2582 ret = 0;
2583
2584out_unlock:
2585 if (ret)
2586 mm_drop_all_locks(mm);
2587
2588 return ret;
2589}
2590
2591static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2592{
2593 if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
2594 /*
2595 * The LSB of head.next can't change to 0 from under
2596 * us because we hold the mm_all_locks_mutex.
2597 *
2598 * We must however clear the bitflag before unlocking
2599 * the vma so the users using the anon_vma->head will
2600 * never see our bitflag.
2601 *
2602 * No need of atomic instructions here, head.next
2603 * can't change from under us until we release the
2604 * anon_vma->root->mutex.
2605 */
2606 if (!__test_and_clear_bit(0, (unsigned long *)
2607 &anon_vma->root->head.next))
2608 BUG();
2609 anon_vma_unlock(anon_vma);
2610 }
2611}
2612
2613static void vm_unlock_mapping(struct address_space *mapping)
2614{
2615 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2616 /*
2617 * AS_MM_ALL_LOCKS can't change to 0 from under us
2618 * because we hold the mm_all_locks_mutex.
2619 */
2620 mutex_unlock(&mapping->i_mmap_mutex);
2621 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2622 &mapping->flags))
2623 BUG();
2624 }
2625}
2626
2627/*
2628 * The mmap_sem cannot be released by the caller until
2629 * mm_drop_all_locks() returns.
2630 */
2631void mm_drop_all_locks(struct mm_struct *mm)
2632{
2633 struct vm_area_struct *vma;
2634 struct anon_vma_chain *avc;
2635
2636 BUG_ON(down_read_trylock(&mm->mmap_sem));
2637 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2638
2639 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2640 if (vma->anon_vma)
2641 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2642 vm_unlock_anon_vma(avc->anon_vma);
2643 if (vma->vm_file && vma->vm_file->f_mapping)
2644 vm_unlock_mapping(vma->vm_file->f_mapping);
2645 }
2646
2647 mutex_unlock(&mm_all_locks_mutex);
2648}
2649
2650/*
2651 * initialise the VMA slab
2652 */
2653void __init mmap_init(void)
2654{
2655 int ret;
2656
2657 ret = percpu_counter_init(&vm_committed_as, 0);
2658 VM_BUG_ON(ret);
2659}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * mm/mmap.c
4 *
5 * Written by obz.
6 *
7 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/backing-dev.h>
15#include <linux/mm.h>
16#include <linux/mm_inline.h>
17#include <linux/shm.h>
18#include <linux/mman.h>
19#include <linux/pagemap.h>
20#include <linux/swap.h>
21#include <linux/syscalls.h>
22#include <linux/capability.h>
23#include <linux/init.h>
24#include <linux/file.h>
25#include <linux/fs.h>
26#include <linux/personality.h>
27#include <linux/security.h>
28#include <linux/hugetlb.h>
29#include <linux/shmem_fs.h>
30#include <linux/profile.h>
31#include <linux/export.h>
32#include <linux/mount.h>
33#include <linux/mempolicy.h>
34#include <linux/rmap.h>
35#include <linux/mmu_notifier.h>
36#include <linux/mmdebug.h>
37#include <linux/perf_event.h>
38#include <linux/audit.h>
39#include <linux/khugepaged.h>
40#include <linux/uprobes.h>
41#include <linux/notifier.h>
42#include <linux/memory.h>
43#include <linux/printk.h>
44#include <linux/userfaultfd_k.h>
45#include <linux/moduleparam.h>
46#include <linux/pkeys.h>
47#include <linux/oom.h>
48#include <linux/sched/mm.h>
49#include <linux/ksm.h>
50#include <linux/memfd.h>
51
52#include <linux/uaccess.h>
53#include <asm/cacheflush.h>
54#include <asm/tlb.h>
55#include <asm/mmu_context.h>
56
57#define CREATE_TRACE_POINTS
58#include <trace/events/mmap.h>
59
60#include "internal.h"
61
62#ifndef arch_mmap_check
63#define arch_mmap_check(addr, len, flags) (0)
64#endif
65
66#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
67const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
68int mmap_rnd_bits_max __ro_after_init = CONFIG_ARCH_MMAP_RND_BITS_MAX;
69int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS;
70#endif
71#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
72const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN;
73const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX;
74int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
75#endif
76
77static bool ignore_rlimit_data;
78core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
79
80/* Update vma->vm_page_prot to reflect vma->vm_flags. */
81void vma_set_page_prot(struct vm_area_struct *vma)
82{
83 unsigned long vm_flags = vma->vm_flags;
84 pgprot_t vm_page_prot;
85
86 vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags);
87 if (vma_wants_writenotify(vma, vm_page_prot)) {
88 vm_flags &= ~VM_SHARED;
89 vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags);
90 }
91 /* remove_protection_ptes reads vma->vm_page_prot without mmap_lock */
92 WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
93}
94
95/*
96 * check_brk_limits() - Use platform specific check of range & verify mlock
97 * limits.
98 * @addr: The address to check
99 * @len: The size of increase.
100 *
101 * Return: 0 on success.
102 */
103static int check_brk_limits(unsigned long addr, unsigned long len)
104{
105 unsigned long mapped_addr;
106
107 mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
108 if (IS_ERR_VALUE(mapped_addr))
109 return mapped_addr;
110
111 return mlock_future_ok(current->mm, current->mm->def_flags, len)
112 ? 0 : -EAGAIN;
113}
114static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma,
115 unsigned long addr, unsigned long request, unsigned long flags);
116SYSCALL_DEFINE1(brk, unsigned long, brk)
117{
118 unsigned long newbrk, oldbrk, origbrk;
119 struct mm_struct *mm = current->mm;
120 struct vm_area_struct *brkvma, *next = NULL;
121 unsigned long min_brk;
122 bool populate = false;
123 LIST_HEAD(uf);
124 struct vma_iterator vmi;
125
126 if (mmap_write_lock_killable(mm))
127 return -EINTR;
128
129 origbrk = mm->brk;
130
131#ifdef CONFIG_COMPAT_BRK
132 /*
133 * CONFIG_COMPAT_BRK can still be overridden by setting
134 * randomize_va_space to 2, which will still cause mm->start_brk
135 * to be arbitrarily shifted
136 */
137 if (current->brk_randomized)
138 min_brk = mm->start_brk;
139 else
140 min_brk = mm->end_data;
141#else
142 min_brk = mm->start_brk;
143#endif
144 if (brk < min_brk)
145 goto out;
146
147 /*
148 * Check against rlimit here. If this check is done later after the test
149 * of oldbrk with newbrk then it can escape the test and let the data
150 * segment grow beyond its set limit the in case where the limit is
151 * not page aligned -Ram Gupta
152 */
153 if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk,
154 mm->end_data, mm->start_data))
155 goto out;
156
157 newbrk = PAGE_ALIGN(brk);
158 oldbrk = PAGE_ALIGN(mm->brk);
159 if (oldbrk == newbrk) {
160 mm->brk = brk;
161 goto success;
162 }
163
164 /* Always allow shrinking brk. */
165 if (brk <= mm->brk) {
166 /* Search one past newbrk */
167 vma_iter_init(&vmi, mm, newbrk);
168 brkvma = vma_find(&vmi, oldbrk);
169 if (!brkvma || brkvma->vm_start >= oldbrk)
170 goto out; /* mapping intersects with an existing non-brk vma. */
171 /*
172 * mm->brk must be protected by write mmap_lock.
173 * do_vmi_align_munmap() will drop the lock on success, so
174 * update it before calling do_vma_munmap().
175 */
176 mm->brk = brk;
177 if (do_vmi_align_munmap(&vmi, brkvma, mm, newbrk, oldbrk, &uf,
178 /* unlock = */ true))
179 goto out;
180
181 goto success_unlocked;
182 }
183
184 if (check_brk_limits(oldbrk, newbrk - oldbrk))
185 goto out;
186
187 /*
188 * Only check if the next VMA is within the stack_guard_gap of the
189 * expansion area
190 */
191 vma_iter_init(&vmi, mm, oldbrk);
192 next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap);
193 if (next && newbrk + PAGE_SIZE > vm_start_gap(next))
194 goto out;
195
196 brkvma = vma_prev_limit(&vmi, mm->start_brk);
197 /* Ok, looks good - let it rip. */
198 if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0)
199 goto out;
200
201 mm->brk = brk;
202 if (mm->def_flags & VM_LOCKED)
203 populate = true;
204
205success:
206 mmap_write_unlock(mm);
207success_unlocked:
208 userfaultfd_unmap_complete(mm, &uf);
209 if (populate)
210 mm_populate(oldbrk, newbrk - oldbrk);
211 return brk;
212
213out:
214 mm->brk = origbrk;
215 mmap_write_unlock(mm);
216 return origbrk;
217}
218
219/*
220 * If a hint addr is less than mmap_min_addr change hint to be as
221 * low as possible but still greater than mmap_min_addr
222 */
223static inline unsigned long round_hint_to_min(unsigned long hint)
224{
225 hint &= PAGE_MASK;
226 if (((void *)hint != NULL) &&
227 (hint < mmap_min_addr))
228 return PAGE_ALIGN(mmap_min_addr);
229 return hint;
230}
231
232bool mlock_future_ok(struct mm_struct *mm, unsigned long flags,
233 unsigned long bytes)
234{
235 unsigned long locked_pages, limit_pages;
236
237 if (!(flags & VM_LOCKED) || capable(CAP_IPC_LOCK))
238 return true;
239
240 locked_pages = bytes >> PAGE_SHIFT;
241 locked_pages += mm->locked_vm;
242
243 limit_pages = rlimit(RLIMIT_MEMLOCK);
244 limit_pages >>= PAGE_SHIFT;
245
246 return locked_pages <= limit_pages;
247}
248
249static inline u64 file_mmap_size_max(struct file *file, struct inode *inode)
250{
251 if (S_ISREG(inode->i_mode))
252 return MAX_LFS_FILESIZE;
253
254 if (S_ISBLK(inode->i_mode))
255 return MAX_LFS_FILESIZE;
256
257 if (S_ISSOCK(inode->i_mode))
258 return MAX_LFS_FILESIZE;
259
260 /* Special "we do even unsigned file positions" case */
261 if (file->f_op->fop_flags & FOP_UNSIGNED_OFFSET)
262 return 0;
263
264 /* Yes, random drivers might want more. But I'm tired of buggy drivers */
265 return ULONG_MAX;
266}
267
268static inline bool file_mmap_ok(struct file *file, struct inode *inode,
269 unsigned long pgoff, unsigned long len)
270{
271 u64 maxsize = file_mmap_size_max(file, inode);
272
273 if (maxsize && len > maxsize)
274 return false;
275 maxsize -= len;
276 if (pgoff > maxsize >> PAGE_SHIFT)
277 return false;
278 return true;
279}
280
281/*
282 * The caller must write-lock current->mm->mmap_lock.
283 */
284unsigned long do_mmap(struct file *file, unsigned long addr,
285 unsigned long len, unsigned long prot,
286 unsigned long flags, vm_flags_t vm_flags,
287 unsigned long pgoff, unsigned long *populate,
288 struct list_head *uf)
289{
290 struct mm_struct *mm = current->mm;
291 int pkey = 0;
292
293 *populate = 0;
294
295 if (!len)
296 return -EINVAL;
297
298 /*
299 * Does the application expect PROT_READ to imply PROT_EXEC?
300 *
301 * (the exception is when the underlying filesystem is noexec
302 * mounted, in which case we don't add PROT_EXEC.)
303 */
304 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
305 if (!(file && path_noexec(&file->f_path)))
306 prot |= PROT_EXEC;
307
308 /* force arch specific MAP_FIXED handling in get_unmapped_area */
309 if (flags & MAP_FIXED_NOREPLACE)
310 flags |= MAP_FIXED;
311
312 if (!(flags & MAP_FIXED))
313 addr = round_hint_to_min(addr);
314
315 /* Careful about overflows.. */
316 len = PAGE_ALIGN(len);
317 if (!len)
318 return -ENOMEM;
319
320 /* offset overflow? */
321 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
322 return -EOVERFLOW;
323
324 /* Too many mappings? */
325 if (mm->map_count > sysctl_max_map_count)
326 return -ENOMEM;
327
328 /*
329 * addr is returned from get_unmapped_area,
330 * There are two cases:
331 * 1> MAP_FIXED == false
332 * unallocated memory, no need to check sealing.
333 * 1> MAP_FIXED == true
334 * sealing is checked inside mmap_region when
335 * do_vmi_munmap is called.
336 */
337
338 if (prot == PROT_EXEC) {
339 pkey = execute_only_pkey(mm);
340 if (pkey < 0)
341 pkey = 0;
342 }
343
344 /* Do simple checking here so the lower-level routines won't have
345 * to. we assume access permissions have been handled by the open
346 * of the memory object, so we don't do any here.
347 */
348 vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) |
349 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
350
351 /* Obtain the address to map to. we verify (or select) it and ensure
352 * that it represents a valid section of the address space.
353 */
354 addr = __get_unmapped_area(file, addr, len, pgoff, flags, vm_flags);
355 if (IS_ERR_VALUE(addr))
356 return addr;
357
358 if (flags & MAP_FIXED_NOREPLACE) {
359 if (find_vma_intersection(mm, addr, addr + len))
360 return -EEXIST;
361 }
362
363 if (flags & MAP_LOCKED)
364 if (!can_do_mlock())
365 return -EPERM;
366
367 if (!mlock_future_ok(mm, vm_flags, len))
368 return -EAGAIN;
369
370 if (file) {
371 struct inode *inode = file_inode(file);
372 unsigned int seals = memfd_file_seals(file);
373 unsigned long flags_mask;
374
375 if (!file_mmap_ok(file, inode, pgoff, len))
376 return -EOVERFLOW;
377
378 flags_mask = LEGACY_MAP_MASK;
379 if (file->f_op->fop_flags & FOP_MMAP_SYNC)
380 flags_mask |= MAP_SYNC;
381
382 switch (flags & MAP_TYPE) {
383 case MAP_SHARED:
384 /*
385 * Force use of MAP_SHARED_VALIDATE with non-legacy
386 * flags. E.g. MAP_SYNC is dangerous to use with
387 * MAP_SHARED as you don't know which consistency model
388 * you will get. We silently ignore unsupported flags
389 * with MAP_SHARED to preserve backward compatibility.
390 */
391 flags &= LEGACY_MAP_MASK;
392 fallthrough;
393 case MAP_SHARED_VALIDATE:
394 if (flags & ~flags_mask)
395 return -EOPNOTSUPP;
396 if (prot & PROT_WRITE) {
397 if (!(file->f_mode & FMODE_WRITE))
398 return -EACCES;
399 if (IS_SWAPFILE(file->f_mapping->host))
400 return -ETXTBSY;
401 }
402
403 /*
404 * Make sure we don't allow writing to an append-only
405 * file..
406 */
407 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
408 return -EACCES;
409
410 vm_flags |= VM_SHARED | VM_MAYSHARE;
411 if (!(file->f_mode & FMODE_WRITE))
412 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
413 else if (is_readonly_sealed(seals, vm_flags))
414 vm_flags &= ~VM_MAYWRITE;
415 fallthrough;
416 case MAP_PRIVATE:
417 if (!(file->f_mode & FMODE_READ))
418 return -EACCES;
419 if (path_noexec(&file->f_path)) {
420 if (vm_flags & VM_EXEC)
421 return -EPERM;
422 vm_flags &= ~VM_MAYEXEC;
423 }
424
425 if (!file->f_op->mmap)
426 return -ENODEV;
427 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
428 return -EINVAL;
429 break;
430
431 default:
432 return -EINVAL;
433 }
434 } else {
435 switch (flags & MAP_TYPE) {
436 case MAP_SHARED:
437 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
438 return -EINVAL;
439 /*
440 * Ignore pgoff.
441 */
442 pgoff = 0;
443 vm_flags |= VM_SHARED | VM_MAYSHARE;
444 break;
445 case MAP_DROPPABLE:
446 if (VM_DROPPABLE == VM_NONE)
447 return -ENOTSUPP;
448 /*
449 * A locked or stack area makes no sense to be droppable.
450 *
451 * Also, since droppable pages can just go away at any time
452 * it makes no sense to copy them on fork or dump them.
453 *
454 * And don't attempt to combine with hugetlb for now.
455 */
456 if (flags & (MAP_LOCKED | MAP_HUGETLB))
457 return -EINVAL;
458 if (vm_flags & (VM_GROWSDOWN | VM_GROWSUP))
459 return -EINVAL;
460
461 vm_flags |= VM_DROPPABLE;
462
463 /*
464 * If the pages can be dropped, then it doesn't make
465 * sense to reserve them.
466 */
467 vm_flags |= VM_NORESERVE;
468
469 /*
470 * Likewise, they're volatile enough that they
471 * shouldn't survive forks or coredumps.
472 */
473 vm_flags |= VM_WIPEONFORK | VM_DONTDUMP;
474 fallthrough;
475 case MAP_PRIVATE:
476 /*
477 * Set pgoff according to addr for anon_vma.
478 */
479 pgoff = addr >> PAGE_SHIFT;
480 break;
481 default:
482 return -EINVAL;
483 }
484 }
485
486 /*
487 * Set 'VM_NORESERVE' if we should not account for the
488 * memory use of this mapping.
489 */
490 if (flags & MAP_NORESERVE) {
491 /* We honor MAP_NORESERVE if allowed to overcommit */
492 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
493 vm_flags |= VM_NORESERVE;
494
495 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
496 if (file && is_file_hugepages(file))
497 vm_flags |= VM_NORESERVE;
498 }
499
500 addr = mmap_region(file, addr, len, vm_flags, pgoff, uf);
501 if (!IS_ERR_VALUE(addr) &&
502 ((vm_flags & VM_LOCKED) ||
503 (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
504 *populate = len;
505 return addr;
506}
507
508unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
509 unsigned long prot, unsigned long flags,
510 unsigned long fd, unsigned long pgoff)
511{
512 struct file *file = NULL;
513 unsigned long retval;
514
515 if (!(flags & MAP_ANONYMOUS)) {
516 audit_mmap_fd(fd, flags);
517 file = fget(fd);
518 if (!file)
519 return -EBADF;
520 if (is_file_hugepages(file)) {
521 len = ALIGN(len, huge_page_size(hstate_file(file)));
522 } else if (unlikely(flags & MAP_HUGETLB)) {
523 retval = -EINVAL;
524 goto out_fput;
525 }
526 } else if (flags & MAP_HUGETLB) {
527 struct hstate *hs;
528
529 hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
530 if (!hs)
531 return -EINVAL;
532
533 len = ALIGN(len, huge_page_size(hs));
534 /*
535 * VM_NORESERVE is used because the reservations will be
536 * taken when vm_ops->mmap() is called
537 */
538 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
539 VM_NORESERVE,
540 HUGETLB_ANONHUGE_INODE,
541 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
542 if (IS_ERR(file))
543 return PTR_ERR(file);
544 }
545
546 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
547out_fput:
548 if (file)
549 fput(file);
550 return retval;
551}
552
553SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
554 unsigned long, prot, unsigned long, flags,
555 unsigned long, fd, unsigned long, pgoff)
556{
557 return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
558}
559
560#ifdef __ARCH_WANT_SYS_OLD_MMAP
561struct mmap_arg_struct {
562 unsigned long addr;
563 unsigned long len;
564 unsigned long prot;
565 unsigned long flags;
566 unsigned long fd;
567 unsigned long offset;
568};
569
570SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
571{
572 struct mmap_arg_struct a;
573
574 if (copy_from_user(&a, arg, sizeof(a)))
575 return -EFAULT;
576 if (offset_in_page(a.offset))
577 return -EINVAL;
578
579 return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
580 a.offset >> PAGE_SHIFT);
581}
582#endif /* __ARCH_WANT_SYS_OLD_MMAP */
583
584/**
585 * unmapped_area() - Find an area between the low_limit and the high_limit with
586 * the correct alignment and offset, all from @info. Note: current->mm is used
587 * for the search.
588 *
589 * @info: The unmapped area information including the range [low_limit -
590 * high_limit), the alignment offset and mask.
591 *
592 * Return: A memory address or -ENOMEM.
593 */
594static unsigned long unmapped_area(struct vm_unmapped_area_info *info)
595{
596 unsigned long length, gap;
597 unsigned long low_limit, high_limit;
598 struct vm_area_struct *tmp;
599 VMA_ITERATOR(vmi, current->mm, 0);
600
601 /* Adjust search length to account for worst case alignment overhead */
602 length = info->length + info->align_mask + info->start_gap;
603 if (length < info->length)
604 return -ENOMEM;
605
606 low_limit = info->low_limit;
607 if (low_limit < mmap_min_addr)
608 low_limit = mmap_min_addr;
609 high_limit = info->high_limit;
610retry:
611 if (vma_iter_area_lowest(&vmi, low_limit, high_limit, length))
612 return -ENOMEM;
613
614 /*
615 * Adjust for the gap first so it doesn't interfere with the
616 * later alignment. The first step is the minimum needed to
617 * fulill the start gap, the next steps is the minimum to align
618 * that. It is the minimum needed to fulill both.
619 */
620 gap = vma_iter_addr(&vmi) + info->start_gap;
621 gap += (info->align_offset - gap) & info->align_mask;
622 tmp = vma_next(&vmi);
623 if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
624 if (vm_start_gap(tmp) < gap + length - 1) {
625 low_limit = tmp->vm_end;
626 vma_iter_reset(&vmi);
627 goto retry;
628 }
629 } else {
630 tmp = vma_prev(&vmi);
631 if (tmp && vm_end_gap(tmp) > gap) {
632 low_limit = vm_end_gap(tmp);
633 vma_iter_reset(&vmi);
634 goto retry;
635 }
636 }
637
638 return gap;
639}
640
641/**
642 * unmapped_area_topdown() - Find an area between the low_limit and the
643 * high_limit with the correct alignment and offset at the highest available
644 * address, all from @info. Note: current->mm is used for the search.
645 *
646 * @info: The unmapped area information including the range [low_limit -
647 * high_limit), the alignment offset and mask.
648 *
649 * Return: A memory address or -ENOMEM.
650 */
651static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
652{
653 unsigned long length, gap, gap_end;
654 unsigned long low_limit, high_limit;
655 struct vm_area_struct *tmp;
656 VMA_ITERATOR(vmi, current->mm, 0);
657
658 /* Adjust search length to account for worst case alignment overhead */
659 length = info->length + info->align_mask + info->start_gap;
660 if (length < info->length)
661 return -ENOMEM;
662
663 low_limit = info->low_limit;
664 if (low_limit < mmap_min_addr)
665 low_limit = mmap_min_addr;
666 high_limit = info->high_limit;
667retry:
668 if (vma_iter_area_highest(&vmi, low_limit, high_limit, length))
669 return -ENOMEM;
670
671 gap = vma_iter_end(&vmi) - info->length;
672 gap -= (gap - info->align_offset) & info->align_mask;
673 gap_end = vma_iter_end(&vmi);
674 tmp = vma_next(&vmi);
675 if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
676 if (vm_start_gap(tmp) < gap_end) {
677 high_limit = vm_start_gap(tmp);
678 vma_iter_reset(&vmi);
679 goto retry;
680 }
681 } else {
682 tmp = vma_prev(&vmi);
683 if (tmp && vm_end_gap(tmp) > gap) {
684 high_limit = tmp->vm_start;
685 vma_iter_reset(&vmi);
686 goto retry;
687 }
688 }
689
690 return gap;
691}
692
693/*
694 * Determine if the allocation needs to ensure that there is no
695 * existing mapping within it's guard gaps, for use as start_gap.
696 */
697static inline unsigned long stack_guard_placement(vm_flags_t vm_flags)
698{
699 if (vm_flags & VM_SHADOW_STACK)
700 return PAGE_SIZE;
701
702 return 0;
703}
704
705/*
706 * Search for an unmapped address range.
707 *
708 * We are looking for a range that:
709 * - does not intersect with any VMA;
710 * - is contained within the [low_limit, high_limit) interval;
711 * - is at least the desired size.
712 * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
713 */
714unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info)
715{
716 unsigned long addr;
717
718 if (info->flags & VM_UNMAPPED_AREA_TOPDOWN)
719 addr = unmapped_area_topdown(info);
720 else
721 addr = unmapped_area(info);
722
723 trace_vm_unmapped_area(addr, info);
724 return addr;
725}
726
727/* Get an address range which is currently unmapped.
728 * For shmat() with addr=0.
729 *
730 * Ugly calling convention alert:
731 * Return value with the low bits set means error value,
732 * ie
733 * if (ret & ~PAGE_MASK)
734 * error = ret;
735 *
736 * This function "knows" that -ENOMEM has the bits set.
737 */
738unsigned long
739generic_get_unmapped_area(struct file *filp, unsigned long addr,
740 unsigned long len, unsigned long pgoff,
741 unsigned long flags, vm_flags_t vm_flags)
742{
743 struct mm_struct *mm = current->mm;
744 struct vm_area_struct *vma, *prev;
745 struct vm_unmapped_area_info info = {};
746 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
747
748 if (len > mmap_end - mmap_min_addr)
749 return -ENOMEM;
750
751 if (flags & MAP_FIXED)
752 return addr;
753
754 if (addr) {
755 addr = PAGE_ALIGN(addr);
756 vma = find_vma_prev(mm, addr, &prev);
757 if (mmap_end - len >= addr && addr >= mmap_min_addr &&
758 (!vma || addr + len <= vm_start_gap(vma)) &&
759 (!prev || addr >= vm_end_gap(prev)))
760 return addr;
761 }
762
763 info.length = len;
764 info.low_limit = mm->mmap_base;
765 info.high_limit = mmap_end;
766 info.start_gap = stack_guard_placement(vm_flags);
767 if (filp && is_file_hugepages(filp))
768 info.align_mask = huge_page_mask_align(filp);
769 return vm_unmapped_area(&info);
770}
771
772#ifndef HAVE_ARCH_UNMAPPED_AREA
773unsigned long
774arch_get_unmapped_area(struct file *filp, unsigned long addr,
775 unsigned long len, unsigned long pgoff,
776 unsigned long flags, vm_flags_t vm_flags)
777{
778 return generic_get_unmapped_area(filp, addr, len, pgoff, flags,
779 vm_flags);
780}
781#endif
782
783/*
784 * This mmap-allocator allocates new areas top-down from below the
785 * stack's low limit (the base):
786 */
787unsigned long
788generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
789 unsigned long len, unsigned long pgoff,
790 unsigned long flags, vm_flags_t vm_flags)
791{
792 struct vm_area_struct *vma, *prev;
793 struct mm_struct *mm = current->mm;
794 struct vm_unmapped_area_info info = {};
795 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
796
797 /* requested length too big for entire address space */
798 if (len > mmap_end - mmap_min_addr)
799 return -ENOMEM;
800
801 if (flags & MAP_FIXED)
802 return addr;
803
804 /* requesting a specific address */
805 if (addr) {
806 addr = PAGE_ALIGN(addr);
807 vma = find_vma_prev(mm, addr, &prev);
808 if (mmap_end - len >= addr && addr >= mmap_min_addr &&
809 (!vma || addr + len <= vm_start_gap(vma)) &&
810 (!prev || addr >= vm_end_gap(prev)))
811 return addr;
812 }
813
814 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
815 info.length = len;
816 info.low_limit = PAGE_SIZE;
817 info.high_limit = arch_get_mmap_base(addr, mm->mmap_base);
818 info.start_gap = stack_guard_placement(vm_flags);
819 if (filp && is_file_hugepages(filp))
820 info.align_mask = huge_page_mask_align(filp);
821 addr = vm_unmapped_area(&info);
822
823 /*
824 * A failed mmap() very likely causes application failure,
825 * so fall back to the bottom-up function here. This scenario
826 * can happen with large stack limits and large mmap()
827 * allocations.
828 */
829 if (offset_in_page(addr)) {
830 VM_BUG_ON(addr != -ENOMEM);
831 info.flags = 0;
832 info.low_limit = TASK_UNMAPPED_BASE;
833 info.high_limit = mmap_end;
834 addr = vm_unmapped_area(&info);
835 }
836
837 return addr;
838}
839
840#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
841unsigned long
842arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
843 unsigned long len, unsigned long pgoff,
844 unsigned long flags, vm_flags_t vm_flags)
845{
846 return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags,
847 vm_flags);
848}
849#endif
850
851unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, struct file *filp,
852 unsigned long addr, unsigned long len,
853 unsigned long pgoff, unsigned long flags,
854 vm_flags_t vm_flags)
855{
856 if (test_bit(MMF_TOPDOWN, &mm->flags))
857 return arch_get_unmapped_area_topdown(filp, addr, len, pgoff,
858 flags, vm_flags);
859 return arch_get_unmapped_area(filp, addr, len, pgoff, flags, vm_flags);
860}
861
862unsigned long
863__get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
864 unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags)
865{
866 unsigned long (*get_area)(struct file *, unsigned long,
867 unsigned long, unsigned long, unsigned long)
868 = NULL;
869
870 unsigned long error = arch_mmap_check(addr, len, flags);
871 if (error)
872 return error;
873
874 /* Careful about overflows.. */
875 if (len > TASK_SIZE)
876 return -ENOMEM;
877
878 if (file) {
879 if (file->f_op->get_unmapped_area)
880 get_area = file->f_op->get_unmapped_area;
881 } else if (flags & MAP_SHARED) {
882 /*
883 * mmap_region() will call shmem_zero_setup() to create a file,
884 * so use shmem's get_unmapped_area in case it can be huge.
885 */
886 get_area = shmem_get_unmapped_area;
887 }
888
889 /* Always treat pgoff as zero for anonymous memory. */
890 if (!file)
891 pgoff = 0;
892
893 if (get_area) {
894 addr = get_area(file, addr, len, pgoff, flags);
895 } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && !file
896 && !addr /* no hint */
897 && IS_ALIGNED(len, PMD_SIZE)) {
898 /* Ensures that larger anonymous mappings are THP aligned. */
899 addr = thp_get_unmapped_area_vmflags(file, addr, len,
900 pgoff, flags, vm_flags);
901 } else {
902 addr = mm_get_unmapped_area_vmflags(current->mm, file, addr, len,
903 pgoff, flags, vm_flags);
904 }
905 if (IS_ERR_VALUE(addr))
906 return addr;
907
908 if (addr > TASK_SIZE - len)
909 return -ENOMEM;
910 if (offset_in_page(addr))
911 return -EINVAL;
912
913 error = security_mmap_addr(addr);
914 return error ? error : addr;
915}
916
917unsigned long
918mm_get_unmapped_area(struct mm_struct *mm, struct file *file,
919 unsigned long addr, unsigned long len,
920 unsigned long pgoff, unsigned long flags)
921{
922 if (test_bit(MMF_TOPDOWN, &mm->flags))
923 return arch_get_unmapped_area_topdown(file, addr, len, pgoff, flags, 0);
924 return arch_get_unmapped_area(file, addr, len, pgoff, flags, 0);
925}
926EXPORT_SYMBOL(mm_get_unmapped_area);
927
928/**
929 * find_vma_intersection() - Look up the first VMA which intersects the interval
930 * @mm: The process address space.
931 * @start_addr: The inclusive start user address.
932 * @end_addr: The exclusive end user address.
933 *
934 * Returns: The first VMA within the provided range, %NULL otherwise. Assumes
935 * start_addr < end_addr.
936 */
937struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
938 unsigned long start_addr,
939 unsigned long end_addr)
940{
941 unsigned long index = start_addr;
942
943 mmap_assert_locked(mm);
944 return mt_find(&mm->mm_mt, &index, end_addr - 1);
945}
946EXPORT_SYMBOL(find_vma_intersection);
947
948/**
949 * find_vma() - Find the VMA for a given address, or the next VMA.
950 * @mm: The mm_struct to check
951 * @addr: The address
952 *
953 * Returns: The VMA associated with addr, or the next VMA.
954 * May return %NULL in the case of no VMA at addr or above.
955 */
956struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
957{
958 unsigned long index = addr;
959
960 mmap_assert_locked(mm);
961 return mt_find(&mm->mm_mt, &index, ULONG_MAX);
962}
963EXPORT_SYMBOL(find_vma);
964
965/**
966 * find_vma_prev() - Find the VMA for a given address, or the next vma and
967 * set %pprev to the previous VMA, if any.
968 * @mm: The mm_struct to check
969 * @addr: The address
970 * @pprev: The pointer to set to the previous VMA
971 *
972 * Note that RCU lock is missing here since the external mmap_lock() is used
973 * instead.
974 *
975 * Returns: The VMA associated with @addr, or the next vma.
976 * May return %NULL in the case of no vma at addr or above.
977 */
978struct vm_area_struct *
979find_vma_prev(struct mm_struct *mm, unsigned long addr,
980 struct vm_area_struct **pprev)
981{
982 struct vm_area_struct *vma;
983 VMA_ITERATOR(vmi, mm, addr);
984
985 vma = vma_iter_load(&vmi);
986 *pprev = vma_prev(&vmi);
987 if (!vma)
988 vma = vma_next(&vmi);
989 return vma;
990}
991
992/*
993 * Verify that the stack growth is acceptable and
994 * update accounting. This is shared with both the
995 * grow-up and grow-down cases.
996 */
997static int acct_stack_growth(struct vm_area_struct *vma,
998 unsigned long size, unsigned long grow)
999{
1000 struct mm_struct *mm = vma->vm_mm;
1001 unsigned long new_start;
1002
1003 /* address space limit tests */
1004 if (!may_expand_vm(mm, vma->vm_flags, grow))
1005 return -ENOMEM;
1006
1007 /* Stack limit test */
1008 if (size > rlimit(RLIMIT_STACK))
1009 return -ENOMEM;
1010
1011 /* mlock limit tests */
1012 if (!mlock_future_ok(mm, vma->vm_flags, grow << PAGE_SHIFT))
1013 return -ENOMEM;
1014
1015 /* Check to ensure the stack will not grow into a hugetlb-only region */
1016 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1017 vma->vm_end - size;
1018 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1019 return -EFAULT;
1020
1021 /*
1022 * Overcommit.. This must be the final test, as it will
1023 * update security statistics.
1024 */
1025 if (security_vm_enough_memory_mm(mm, grow))
1026 return -ENOMEM;
1027
1028 return 0;
1029}
1030
1031#if defined(CONFIG_STACK_GROWSUP)
1032/*
1033 * PA-RISC uses this for its stack.
1034 * vma is the last one with address > vma->vm_end. Have to extend vma.
1035 */
1036static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1037{
1038 struct mm_struct *mm = vma->vm_mm;
1039 struct vm_area_struct *next;
1040 unsigned long gap_addr;
1041 int error = 0;
1042 VMA_ITERATOR(vmi, mm, vma->vm_start);
1043
1044 if (!(vma->vm_flags & VM_GROWSUP))
1045 return -EFAULT;
1046
1047 mmap_assert_write_locked(mm);
1048
1049 /* Guard against exceeding limits of the address space. */
1050 address &= PAGE_MASK;
1051 if (address >= (TASK_SIZE & PAGE_MASK))
1052 return -ENOMEM;
1053 address += PAGE_SIZE;
1054
1055 /* Enforce stack_guard_gap */
1056 gap_addr = address + stack_guard_gap;
1057
1058 /* Guard against overflow */
1059 if (gap_addr < address || gap_addr > TASK_SIZE)
1060 gap_addr = TASK_SIZE;
1061
1062 next = find_vma_intersection(mm, vma->vm_end, gap_addr);
1063 if (next && vma_is_accessible(next)) {
1064 if (!(next->vm_flags & VM_GROWSUP))
1065 return -ENOMEM;
1066 /* Check that both stack segments have the same anon_vma? */
1067 }
1068
1069 if (next)
1070 vma_iter_prev_range_limit(&vmi, address);
1071
1072 vma_iter_config(&vmi, vma->vm_start, address);
1073 if (vma_iter_prealloc(&vmi, vma))
1074 return -ENOMEM;
1075
1076 /* We must make sure the anon_vma is allocated. */
1077 if (unlikely(anon_vma_prepare(vma))) {
1078 vma_iter_free(&vmi);
1079 return -ENOMEM;
1080 }
1081
1082 /* Lock the VMA before expanding to prevent concurrent page faults */
1083 vma_start_write(vma);
1084 /* We update the anon VMA tree. */
1085 anon_vma_lock_write(vma->anon_vma);
1086
1087 /* Somebody else might have raced and expanded it already */
1088 if (address > vma->vm_end) {
1089 unsigned long size, grow;
1090
1091 size = address - vma->vm_start;
1092 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1093
1094 error = -ENOMEM;
1095 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
1096 error = acct_stack_growth(vma, size, grow);
1097 if (!error) {
1098 if (vma->vm_flags & VM_LOCKED)
1099 mm->locked_vm += grow;
1100 vm_stat_account(mm, vma->vm_flags, grow);
1101 anon_vma_interval_tree_pre_update_vma(vma);
1102 vma->vm_end = address;
1103 /* Overwrite old entry in mtree. */
1104 vma_iter_store(&vmi, vma);
1105 anon_vma_interval_tree_post_update_vma(vma);
1106
1107 perf_event_mmap(vma);
1108 }
1109 }
1110 }
1111 anon_vma_unlock_write(vma->anon_vma);
1112 vma_iter_free(&vmi);
1113 validate_mm(mm);
1114 return error;
1115}
1116#endif /* CONFIG_STACK_GROWSUP */
1117
1118/*
1119 * vma is the first one with address < vma->vm_start. Have to extend vma.
1120 * mmap_lock held for writing.
1121 */
1122int expand_downwards(struct vm_area_struct *vma, unsigned long address)
1123{
1124 struct mm_struct *mm = vma->vm_mm;
1125 struct vm_area_struct *prev;
1126 int error = 0;
1127 VMA_ITERATOR(vmi, mm, vma->vm_start);
1128
1129 if (!(vma->vm_flags & VM_GROWSDOWN))
1130 return -EFAULT;
1131
1132 mmap_assert_write_locked(mm);
1133
1134 address &= PAGE_MASK;
1135 if (address < mmap_min_addr || address < FIRST_USER_ADDRESS)
1136 return -EPERM;
1137
1138 /* Enforce stack_guard_gap */
1139 prev = vma_prev(&vmi);
1140 /* Check that both stack segments have the same anon_vma? */
1141 if (prev) {
1142 if (!(prev->vm_flags & VM_GROWSDOWN) &&
1143 vma_is_accessible(prev) &&
1144 (address - prev->vm_end < stack_guard_gap))
1145 return -ENOMEM;
1146 }
1147
1148 if (prev)
1149 vma_iter_next_range_limit(&vmi, vma->vm_start);
1150
1151 vma_iter_config(&vmi, address, vma->vm_end);
1152 if (vma_iter_prealloc(&vmi, vma))
1153 return -ENOMEM;
1154
1155 /* We must make sure the anon_vma is allocated. */
1156 if (unlikely(anon_vma_prepare(vma))) {
1157 vma_iter_free(&vmi);
1158 return -ENOMEM;
1159 }
1160
1161 /* Lock the VMA before expanding to prevent concurrent page faults */
1162 vma_start_write(vma);
1163 /* We update the anon VMA tree. */
1164 anon_vma_lock_write(vma->anon_vma);
1165
1166 /* Somebody else might have raced and expanded it already */
1167 if (address < vma->vm_start) {
1168 unsigned long size, grow;
1169
1170 size = vma->vm_end - address;
1171 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1172
1173 error = -ENOMEM;
1174 if (grow <= vma->vm_pgoff) {
1175 error = acct_stack_growth(vma, size, grow);
1176 if (!error) {
1177 if (vma->vm_flags & VM_LOCKED)
1178 mm->locked_vm += grow;
1179 vm_stat_account(mm, vma->vm_flags, grow);
1180 anon_vma_interval_tree_pre_update_vma(vma);
1181 vma->vm_start = address;
1182 vma->vm_pgoff -= grow;
1183 /* Overwrite old entry in mtree. */
1184 vma_iter_store(&vmi, vma);
1185 anon_vma_interval_tree_post_update_vma(vma);
1186
1187 perf_event_mmap(vma);
1188 }
1189 }
1190 }
1191 anon_vma_unlock_write(vma->anon_vma);
1192 vma_iter_free(&vmi);
1193 validate_mm(mm);
1194 return error;
1195}
1196
1197/* enforced gap between the expanding stack and other mappings. */
1198unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
1199
1200static int __init cmdline_parse_stack_guard_gap(char *p)
1201{
1202 unsigned long val;
1203 char *endptr;
1204
1205 val = simple_strtoul(p, &endptr, 10);
1206 if (!*endptr)
1207 stack_guard_gap = val << PAGE_SHIFT;
1208
1209 return 1;
1210}
1211__setup("stack_guard_gap=", cmdline_parse_stack_guard_gap);
1212
1213#ifdef CONFIG_STACK_GROWSUP
1214int expand_stack_locked(struct vm_area_struct *vma, unsigned long address)
1215{
1216 return expand_upwards(vma, address);
1217}
1218
1219struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, unsigned long addr)
1220{
1221 struct vm_area_struct *vma, *prev;
1222
1223 addr &= PAGE_MASK;
1224 vma = find_vma_prev(mm, addr, &prev);
1225 if (vma && (vma->vm_start <= addr))
1226 return vma;
1227 if (!prev)
1228 return NULL;
1229 if (expand_stack_locked(prev, addr))
1230 return NULL;
1231 if (prev->vm_flags & VM_LOCKED)
1232 populate_vma_page_range(prev, addr, prev->vm_end, NULL);
1233 return prev;
1234}
1235#else
1236int expand_stack_locked(struct vm_area_struct *vma, unsigned long address)
1237{
1238 return expand_downwards(vma, address);
1239}
1240
1241struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm, unsigned long addr)
1242{
1243 struct vm_area_struct *vma;
1244 unsigned long start;
1245
1246 addr &= PAGE_MASK;
1247 vma = find_vma(mm, addr);
1248 if (!vma)
1249 return NULL;
1250 if (vma->vm_start <= addr)
1251 return vma;
1252 start = vma->vm_start;
1253 if (expand_stack_locked(vma, addr))
1254 return NULL;
1255 if (vma->vm_flags & VM_LOCKED)
1256 populate_vma_page_range(vma, addr, start, NULL);
1257 return vma;
1258}
1259#endif
1260
1261#if defined(CONFIG_STACK_GROWSUP)
1262
1263#define vma_expand_up(vma,addr) expand_upwards(vma, addr)
1264#define vma_expand_down(vma, addr) (-EFAULT)
1265
1266#else
1267
1268#define vma_expand_up(vma,addr) (-EFAULT)
1269#define vma_expand_down(vma, addr) expand_downwards(vma, addr)
1270
1271#endif
1272
1273/*
1274 * expand_stack(): legacy interface for page faulting. Don't use unless
1275 * you have to.
1276 *
1277 * This is called with the mm locked for reading, drops the lock, takes
1278 * the lock for writing, tries to look up a vma again, expands it if
1279 * necessary, and downgrades the lock to reading again.
1280 *
1281 * If no vma is found or it can't be expanded, it returns NULL and has
1282 * dropped the lock.
1283 */
1284struct vm_area_struct *expand_stack(struct mm_struct *mm, unsigned long addr)
1285{
1286 struct vm_area_struct *vma, *prev;
1287
1288 mmap_read_unlock(mm);
1289 if (mmap_write_lock_killable(mm))
1290 return NULL;
1291
1292 vma = find_vma_prev(mm, addr, &prev);
1293 if (vma && vma->vm_start <= addr)
1294 goto success;
1295
1296 if (prev && !vma_expand_up(prev, addr)) {
1297 vma = prev;
1298 goto success;
1299 }
1300
1301 if (vma && !vma_expand_down(vma, addr))
1302 goto success;
1303
1304 mmap_write_unlock(mm);
1305 return NULL;
1306
1307success:
1308 mmap_write_downgrade(mm);
1309 return vma;
1310}
1311
1312/* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls.
1313 * @mm: The mm_struct
1314 * @start: The start address to munmap
1315 * @len: The length to be munmapped.
1316 * @uf: The userfaultfd list_head
1317 *
1318 * Return: 0 on success, error otherwise.
1319 */
1320int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
1321 struct list_head *uf)
1322{
1323 VMA_ITERATOR(vmi, mm, start);
1324
1325 return do_vmi_munmap(&vmi, mm, start, len, uf, false);
1326}
1327
1328unsigned long mmap_region(struct file *file, unsigned long addr,
1329 unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
1330 struct list_head *uf)
1331{
1332 unsigned long ret;
1333 bool writable_file_mapping = false;
1334
1335 /* Check to see if MDWE is applicable. */
1336 if (map_deny_write_exec(vm_flags, vm_flags))
1337 return -EACCES;
1338
1339 /* Allow architectures to sanity-check the vm_flags. */
1340 if (!arch_validate_flags(vm_flags))
1341 return -EINVAL;
1342
1343 /* Map writable and ensure this isn't a sealed memfd. */
1344 if (file && is_shared_maywrite(vm_flags)) {
1345 int error = mapping_map_writable(file->f_mapping);
1346
1347 if (error)
1348 return error;
1349 writable_file_mapping = true;
1350 }
1351
1352 ret = __mmap_region(file, addr, len, vm_flags, pgoff, uf);
1353
1354 /* Clear our write mapping regardless of error. */
1355 if (writable_file_mapping)
1356 mapping_unmap_writable(file->f_mapping);
1357
1358 validate_mm(current->mm);
1359 return ret;
1360}
1361
1362static int __vm_munmap(unsigned long start, size_t len, bool unlock)
1363{
1364 int ret;
1365 struct mm_struct *mm = current->mm;
1366 LIST_HEAD(uf);
1367 VMA_ITERATOR(vmi, mm, start);
1368
1369 if (mmap_write_lock_killable(mm))
1370 return -EINTR;
1371
1372 ret = do_vmi_munmap(&vmi, mm, start, len, &uf, unlock);
1373 if (ret || !unlock)
1374 mmap_write_unlock(mm);
1375
1376 userfaultfd_unmap_complete(mm, &uf);
1377 return ret;
1378}
1379
1380int vm_munmap(unsigned long start, size_t len)
1381{
1382 return __vm_munmap(start, len, false);
1383}
1384EXPORT_SYMBOL(vm_munmap);
1385
1386SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1387{
1388 addr = untagged_addr(addr);
1389 return __vm_munmap(addr, len, true);
1390}
1391
1392
1393/*
1394 * Emulation of deprecated remap_file_pages() syscall.
1395 */
1396SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
1397 unsigned long, prot, unsigned long, pgoff, unsigned long, flags)
1398{
1399
1400 struct mm_struct *mm = current->mm;
1401 struct vm_area_struct *vma;
1402 unsigned long populate = 0;
1403 unsigned long ret = -EINVAL;
1404 struct file *file;
1405 vm_flags_t vm_flags;
1406
1407 pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n",
1408 current->comm, current->pid);
1409
1410 if (prot)
1411 return ret;
1412 start = start & PAGE_MASK;
1413 size = size & PAGE_MASK;
1414
1415 if (start + size <= start)
1416 return ret;
1417
1418 /* Does pgoff wrap? */
1419 if (pgoff + (size >> PAGE_SHIFT) < pgoff)
1420 return ret;
1421
1422 if (mmap_read_lock_killable(mm))
1423 return -EINTR;
1424
1425 /*
1426 * Look up VMA under read lock first so we can perform the security
1427 * without holding locks (which can be problematic). We reacquire a
1428 * write lock later and check nothing changed underneath us.
1429 */
1430 vma = vma_lookup(mm, start);
1431
1432 if (!vma || !(vma->vm_flags & VM_SHARED)) {
1433 mmap_read_unlock(mm);
1434 return -EINVAL;
1435 }
1436
1437 prot |= vma->vm_flags & VM_READ ? PROT_READ : 0;
1438 prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0;
1439 prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0;
1440
1441 flags &= MAP_NONBLOCK;
1442 flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
1443 if (vma->vm_flags & VM_LOCKED)
1444 flags |= MAP_LOCKED;
1445
1446 /* Save vm_flags used to calculate prot and flags, and recheck later. */
1447 vm_flags = vma->vm_flags;
1448 file = get_file(vma->vm_file);
1449
1450 mmap_read_unlock(mm);
1451
1452 /* Call outside mmap_lock to be consistent with other callers. */
1453 ret = security_mmap_file(file, prot, flags);
1454 if (ret) {
1455 fput(file);
1456 return ret;
1457 }
1458
1459 ret = -EINVAL;
1460
1461 /* OK security check passed, take write lock + let it rip. */
1462 if (mmap_write_lock_killable(mm)) {
1463 fput(file);
1464 return -EINTR;
1465 }
1466
1467 vma = vma_lookup(mm, start);
1468
1469 if (!vma)
1470 goto out;
1471
1472 /* Make sure things didn't change under us. */
1473 if (vma->vm_flags != vm_flags)
1474 goto out;
1475 if (vma->vm_file != file)
1476 goto out;
1477
1478 if (start + size > vma->vm_end) {
1479 VMA_ITERATOR(vmi, mm, vma->vm_end);
1480 struct vm_area_struct *next, *prev = vma;
1481
1482 for_each_vma_range(vmi, next, start + size) {
1483 /* hole between vmas ? */
1484 if (next->vm_start != prev->vm_end)
1485 goto out;
1486
1487 if (next->vm_file != vma->vm_file)
1488 goto out;
1489
1490 if (next->vm_flags != vma->vm_flags)
1491 goto out;
1492
1493 if (start + size <= next->vm_end)
1494 break;
1495
1496 prev = next;
1497 }
1498
1499 if (!next)
1500 goto out;
1501 }
1502
1503 ret = do_mmap(vma->vm_file, start, size,
1504 prot, flags, 0, pgoff, &populate, NULL);
1505out:
1506 mmap_write_unlock(mm);
1507 fput(file);
1508 if (populate)
1509 mm_populate(ret, populate);
1510 if (!IS_ERR_VALUE(ret))
1511 ret = 0;
1512 return ret;
1513}
1514
1515/*
1516 * do_brk_flags() - Increase the brk vma if the flags match.
1517 * @vmi: The vma iterator
1518 * @addr: The start address
1519 * @len: The length of the increase
1520 * @vma: The vma,
1521 * @flags: The VMA Flags
1522 *
1523 * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags
1524 * do not match then create a new anonymous VMA. Eventually we may be able to
1525 * do some brk-specific accounting here.
1526 */
1527static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
1528 unsigned long addr, unsigned long len, unsigned long flags)
1529{
1530 struct mm_struct *mm = current->mm;
1531
1532 /*
1533 * Check against address space limits by the changed size
1534 * Note: This happens *after* clearing old mappings in some code paths.
1535 */
1536 flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1537 if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
1538 return -ENOMEM;
1539
1540 if (mm->map_count > sysctl_max_map_count)
1541 return -ENOMEM;
1542
1543 if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
1544 return -ENOMEM;
1545
1546 /*
1547 * Expand the existing vma if possible; Note that singular lists do not
1548 * occur after forking, so the expand will only happen on new VMAs.
1549 */
1550 if (vma && vma->vm_end == addr) {
1551 VMG_STATE(vmg, mm, vmi, addr, addr + len, flags, PHYS_PFN(addr));
1552
1553 vmg.prev = vma;
1554 /* vmi is positioned at prev, which this mode expects. */
1555 vmg.merge_flags = VMG_FLAG_JUST_EXPAND;
1556
1557 if (vma_merge_new_range(&vmg))
1558 goto out;
1559 else if (vmg_nomem(&vmg))
1560 goto unacct_fail;
1561 }
1562
1563 if (vma)
1564 vma_iter_next_range(vmi);
1565 /* create a vma struct for an anonymous mapping */
1566 vma = vm_area_alloc(mm);
1567 if (!vma)
1568 goto unacct_fail;
1569
1570 vma_set_anonymous(vma);
1571 vma_set_range(vma, addr, addr + len, addr >> PAGE_SHIFT);
1572 vm_flags_init(vma, flags);
1573 vma->vm_page_prot = vm_get_page_prot(flags);
1574 vma_start_write(vma);
1575 if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL))
1576 goto mas_store_fail;
1577
1578 mm->map_count++;
1579 validate_mm(mm);
1580 ksm_add_vma(vma);
1581out:
1582 perf_event_mmap(vma);
1583 mm->total_vm += len >> PAGE_SHIFT;
1584 mm->data_vm += len >> PAGE_SHIFT;
1585 if (flags & VM_LOCKED)
1586 mm->locked_vm += (len >> PAGE_SHIFT);
1587 vm_flags_set(vma, VM_SOFTDIRTY);
1588 return 0;
1589
1590mas_store_fail:
1591 vm_area_free(vma);
1592unacct_fail:
1593 vm_unacct_memory(len >> PAGE_SHIFT);
1594 return -ENOMEM;
1595}
1596
1597int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags)
1598{
1599 struct mm_struct *mm = current->mm;
1600 struct vm_area_struct *vma = NULL;
1601 unsigned long len;
1602 int ret;
1603 bool populate;
1604 LIST_HEAD(uf);
1605 VMA_ITERATOR(vmi, mm, addr);
1606
1607 len = PAGE_ALIGN(request);
1608 if (len < request)
1609 return -ENOMEM;
1610 if (!len)
1611 return 0;
1612
1613 /* Until we need other flags, refuse anything except VM_EXEC. */
1614 if ((flags & (~VM_EXEC)) != 0)
1615 return -EINVAL;
1616
1617 if (mmap_write_lock_killable(mm))
1618 return -EINTR;
1619
1620 ret = check_brk_limits(addr, len);
1621 if (ret)
1622 goto limits_failed;
1623
1624 ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0);
1625 if (ret)
1626 goto munmap_failed;
1627
1628 vma = vma_prev(&vmi);
1629 ret = do_brk_flags(&vmi, vma, addr, len, flags);
1630 populate = ((mm->def_flags & VM_LOCKED) != 0);
1631 mmap_write_unlock(mm);
1632 userfaultfd_unmap_complete(mm, &uf);
1633 if (populate && !ret)
1634 mm_populate(addr, len);
1635 return ret;
1636
1637munmap_failed:
1638limits_failed:
1639 mmap_write_unlock(mm);
1640 return ret;
1641}
1642EXPORT_SYMBOL(vm_brk_flags);
1643
1644/* Release all mmaps. */
1645void exit_mmap(struct mm_struct *mm)
1646{
1647 struct mmu_gather tlb;
1648 struct vm_area_struct *vma;
1649 unsigned long nr_accounted = 0;
1650 VMA_ITERATOR(vmi, mm, 0);
1651 int count = 0;
1652
1653 /* mm's last user has gone, and its about to be pulled down */
1654 mmu_notifier_release(mm);
1655
1656 mmap_read_lock(mm);
1657 arch_exit_mmap(mm);
1658
1659 vma = vma_next(&vmi);
1660 if (!vma || unlikely(xa_is_zero(vma))) {
1661 /* Can happen if dup_mmap() received an OOM */
1662 mmap_read_unlock(mm);
1663 mmap_write_lock(mm);
1664 goto destroy;
1665 }
1666
1667 lru_add_drain();
1668 flush_cache_mm(mm);
1669 tlb_gather_mmu_fullmm(&tlb, mm);
1670 /* update_hiwater_rss(mm) here? but nobody should be looking */
1671 /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */
1672 unmap_vmas(&tlb, &vmi.mas, vma, 0, ULONG_MAX, ULONG_MAX, false);
1673 mmap_read_unlock(mm);
1674
1675 /*
1676 * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper
1677 * because the memory has been already freed.
1678 */
1679 set_bit(MMF_OOM_SKIP, &mm->flags);
1680 mmap_write_lock(mm);
1681 mt_clear_in_rcu(&mm->mm_mt);
1682 vma_iter_set(&vmi, vma->vm_end);
1683 free_pgtables(&tlb, &vmi.mas, vma, FIRST_USER_ADDRESS,
1684 USER_PGTABLES_CEILING, true);
1685 tlb_finish_mmu(&tlb);
1686
1687 /*
1688 * Walk the list again, actually closing and freeing it, with preemption
1689 * enabled, without holding any MM locks besides the unreachable
1690 * mmap_write_lock.
1691 */
1692 vma_iter_set(&vmi, vma->vm_end);
1693 do {
1694 if (vma->vm_flags & VM_ACCOUNT)
1695 nr_accounted += vma_pages(vma);
1696 remove_vma(vma, /* unreachable = */ true);
1697 count++;
1698 cond_resched();
1699 vma = vma_next(&vmi);
1700 } while (vma && likely(!xa_is_zero(vma)));
1701
1702 BUG_ON(count != mm->map_count);
1703
1704 trace_exit_mmap(mm);
1705destroy:
1706 __mt_destroy(&mm->mm_mt);
1707 mmap_write_unlock(mm);
1708 vm_unacct_memory(nr_accounted);
1709}
1710
1711/* Insert vm structure into process list sorted by address
1712 * and into the inode's i_mmap tree. If vm_file is non-NULL
1713 * then i_mmap_rwsem is taken here.
1714 */
1715int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
1716{
1717 unsigned long charged = vma_pages(vma);
1718
1719
1720 if (find_vma_intersection(mm, vma->vm_start, vma->vm_end))
1721 return -ENOMEM;
1722
1723 if ((vma->vm_flags & VM_ACCOUNT) &&
1724 security_vm_enough_memory_mm(mm, charged))
1725 return -ENOMEM;
1726
1727 /*
1728 * The vm_pgoff of a purely anonymous vma should be irrelevant
1729 * until its first write fault, when page's anon_vma and index
1730 * are set. But now set the vm_pgoff it will almost certainly
1731 * end up with (unless mremap moves it elsewhere before that
1732 * first wfault), so /proc/pid/maps tells a consistent story.
1733 *
1734 * By setting it to reflect the virtual start address of the
1735 * vma, merges and splits can happen in a seamless way, just
1736 * using the existing file pgoff checks and manipulations.
1737 * Similarly in do_mmap and in do_brk_flags.
1738 */
1739 if (vma_is_anonymous(vma)) {
1740 BUG_ON(vma->anon_vma);
1741 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
1742 }
1743
1744 if (vma_link(mm, vma)) {
1745 if (vma->vm_flags & VM_ACCOUNT)
1746 vm_unacct_memory(charged);
1747 return -ENOMEM;
1748 }
1749
1750 return 0;
1751}
1752
1753/*
1754 * Return true if the calling process may expand its vm space by the passed
1755 * number of pages
1756 */
1757bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages)
1758{
1759 if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT)
1760 return false;
1761
1762 if (is_data_mapping(flags) &&
1763 mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
1764 /* Workaround for Valgrind */
1765 if (rlimit(RLIMIT_DATA) == 0 &&
1766 mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT)
1767 return true;
1768
1769 pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n",
1770 current->comm, current->pid,
1771 (mm->data_vm + npages) << PAGE_SHIFT,
1772 rlimit(RLIMIT_DATA),
1773 ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data");
1774
1775 if (!ignore_rlimit_data)
1776 return false;
1777 }
1778
1779 return true;
1780}
1781
1782void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
1783{
1784 WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages);
1785
1786 if (is_exec_mapping(flags))
1787 mm->exec_vm += npages;
1788 else if (is_stack_mapping(flags))
1789 mm->stack_vm += npages;
1790 else if (is_data_mapping(flags))
1791 mm->data_vm += npages;
1792}
1793
1794static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
1795
1796/*
1797 * Close hook, called for unmap() and on the old vma for mremap().
1798 *
1799 * Having a close hook prevents vma merging regardless of flags.
1800 */
1801static void special_mapping_close(struct vm_area_struct *vma)
1802{
1803 const struct vm_special_mapping *sm = vma->vm_private_data;
1804
1805 if (sm->close)
1806 sm->close(sm, vma);
1807}
1808
1809static const char *special_mapping_name(struct vm_area_struct *vma)
1810{
1811 return ((struct vm_special_mapping *)vma->vm_private_data)->name;
1812}
1813
1814static int special_mapping_mremap(struct vm_area_struct *new_vma)
1815{
1816 struct vm_special_mapping *sm = new_vma->vm_private_data;
1817
1818 if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
1819 return -EFAULT;
1820
1821 if (sm->mremap)
1822 return sm->mremap(sm, new_vma);
1823
1824 return 0;
1825}
1826
1827static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr)
1828{
1829 /*
1830 * Forbid splitting special mappings - kernel has expectations over
1831 * the number of pages in mapping. Together with VM_DONTEXPAND
1832 * the size of vma should stay the same over the special mapping's
1833 * lifetime.
1834 */
1835 return -EINVAL;
1836}
1837
1838static const struct vm_operations_struct special_mapping_vmops = {
1839 .close = special_mapping_close,
1840 .fault = special_mapping_fault,
1841 .mremap = special_mapping_mremap,
1842 .name = special_mapping_name,
1843 /* vDSO code relies that VVAR can't be accessed remotely */
1844 .access = NULL,
1845 .may_split = special_mapping_split,
1846};
1847
1848static vm_fault_t special_mapping_fault(struct vm_fault *vmf)
1849{
1850 struct vm_area_struct *vma = vmf->vma;
1851 pgoff_t pgoff;
1852 struct page **pages;
1853 struct vm_special_mapping *sm = vma->vm_private_data;
1854
1855 if (sm->fault)
1856 return sm->fault(sm, vmf->vma, vmf);
1857
1858 pages = sm->pages;
1859
1860 for (pgoff = vmf->pgoff; pgoff && *pages; ++pages)
1861 pgoff--;
1862
1863 if (*pages) {
1864 struct page *page = *pages;
1865 get_page(page);
1866 vmf->page = page;
1867 return 0;
1868 }
1869
1870 return VM_FAULT_SIGBUS;
1871}
1872
1873static struct vm_area_struct *__install_special_mapping(
1874 struct mm_struct *mm,
1875 unsigned long addr, unsigned long len,
1876 unsigned long vm_flags, void *priv,
1877 const struct vm_operations_struct *ops)
1878{
1879 int ret;
1880 struct vm_area_struct *vma;
1881
1882 vma = vm_area_alloc(mm);
1883 if (unlikely(vma == NULL))
1884 return ERR_PTR(-ENOMEM);
1885
1886 vma_set_range(vma, addr, addr + len, 0);
1887 vm_flags_init(vma, (vm_flags | mm->def_flags |
1888 VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
1889 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
1890
1891 vma->vm_ops = ops;
1892 vma->vm_private_data = priv;
1893
1894 ret = insert_vm_struct(mm, vma);
1895 if (ret)
1896 goto out;
1897
1898 vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
1899
1900 perf_event_mmap(vma);
1901
1902 return vma;
1903
1904out:
1905 vm_area_free(vma);
1906 return ERR_PTR(ret);
1907}
1908
1909bool vma_is_special_mapping(const struct vm_area_struct *vma,
1910 const struct vm_special_mapping *sm)
1911{
1912 return vma->vm_private_data == sm &&
1913 vma->vm_ops == &special_mapping_vmops;
1914}
1915
1916/*
1917 * Called with mm->mmap_lock held for writing.
1918 * Insert a new vma covering the given region, with the given flags.
1919 * Its pages are supplied by the given array of struct page *.
1920 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
1921 * The region past the last page supplied will always produce SIGBUS.
1922 * The array pointer and the pages it points to are assumed to stay alive
1923 * for as long as this mapping might exist.
1924 */
1925struct vm_area_struct *_install_special_mapping(
1926 struct mm_struct *mm,
1927 unsigned long addr, unsigned long len,
1928 unsigned long vm_flags, const struct vm_special_mapping *spec)
1929{
1930 return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec,
1931 &special_mapping_vmops);
1932}
1933
1934/*
1935 * initialise the percpu counter for VM
1936 */
1937void __init mmap_init(void)
1938{
1939 int ret;
1940
1941 ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
1942 VM_BUG_ON(ret);
1943}
1944
1945/*
1946 * Initialise sysctl_user_reserve_kbytes.
1947 *
1948 * This is intended to prevent a user from starting a single memory hogging
1949 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
1950 * mode.
1951 *
1952 * The default value is min(3% of free memory, 128MB)
1953 * 128MB is enough to recover with sshd/login, bash, and top/kill.
1954 */
1955static int init_user_reserve(void)
1956{
1957 unsigned long free_kbytes;
1958
1959 free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
1960
1961 sysctl_user_reserve_kbytes = min(free_kbytes / 32, SZ_128K);
1962 return 0;
1963}
1964subsys_initcall(init_user_reserve);
1965
1966/*
1967 * Initialise sysctl_admin_reserve_kbytes.
1968 *
1969 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
1970 * to log in and kill a memory hogging process.
1971 *
1972 * Systems with more than 256MB will reserve 8MB, enough to recover
1973 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
1974 * only reserve 3% of free pages by default.
1975 */
1976static int init_admin_reserve(void)
1977{
1978 unsigned long free_kbytes;
1979
1980 free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
1981
1982 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, SZ_8K);
1983 return 0;
1984}
1985subsys_initcall(init_admin_reserve);
1986
1987/*
1988 * Reinititalise user and admin reserves if memory is added or removed.
1989 *
1990 * The default user reserve max is 128MB, and the default max for the
1991 * admin reserve is 8MB. These are usually, but not always, enough to
1992 * enable recovery from a memory hogging process using login/sshd, a shell,
1993 * and tools like top. It may make sense to increase or even disable the
1994 * reserve depending on the existence of swap or variations in the recovery
1995 * tools. So, the admin may have changed them.
1996 *
1997 * If memory is added and the reserves have been eliminated or increased above
1998 * the default max, then we'll trust the admin.
1999 *
2000 * If memory is removed and there isn't enough free memory, then we
2001 * need to reset the reserves.
2002 *
2003 * Otherwise keep the reserve set by the admin.
2004 */
2005static int reserve_mem_notifier(struct notifier_block *nb,
2006 unsigned long action, void *data)
2007{
2008 unsigned long tmp, free_kbytes;
2009
2010 switch (action) {
2011 case MEM_ONLINE:
2012 /* Default max is 128MB. Leave alone if modified by operator. */
2013 tmp = sysctl_user_reserve_kbytes;
2014 if (tmp > 0 && tmp < SZ_128K)
2015 init_user_reserve();
2016
2017 /* Default max is 8MB. Leave alone if modified by operator. */
2018 tmp = sysctl_admin_reserve_kbytes;
2019 if (tmp > 0 && tmp < SZ_8K)
2020 init_admin_reserve();
2021
2022 break;
2023 case MEM_OFFLINE:
2024 free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
2025
2026 if (sysctl_user_reserve_kbytes > free_kbytes) {
2027 init_user_reserve();
2028 pr_info("vm.user_reserve_kbytes reset to %lu\n",
2029 sysctl_user_reserve_kbytes);
2030 }
2031
2032 if (sysctl_admin_reserve_kbytes > free_kbytes) {
2033 init_admin_reserve();
2034 pr_info("vm.admin_reserve_kbytes reset to %lu\n",
2035 sysctl_admin_reserve_kbytes);
2036 }
2037 break;
2038 default:
2039 break;
2040 }
2041 return NOTIFY_OK;
2042}
2043
2044static int __meminit init_reserve_notifier(void)
2045{
2046 if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI))
2047 pr_err("Failed registering memory add/remove notifier for admin reserve\n");
2048
2049 return 0;
2050}
2051subsys_initcall(init_reserve_notifier);
2052
2053/*
2054 * Relocate a VMA downwards by shift bytes. There cannot be any VMAs between
2055 * this VMA and its relocated range, which will now reside at [vma->vm_start -
2056 * shift, vma->vm_end - shift).
2057 *
2058 * This function is almost certainly NOT what you want for anything other than
2059 * early executable temporary stack relocation.
2060 */
2061int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
2062{
2063 /*
2064 * The process proceeds as follows:
2065 *
2066 * 1) Use shift to calculate the new vma endpoints.
2067 * 2) Extend vma to cover both the old and new ranges. This ensures the
2068 * arguments passed to subsequent functions are consistent.
2069 * 3) Move vma's page tables to the new range.
2070 * 4) Free up any cleared pgd range.
2071 * 5) Shrink the vma to cover only the new range.
2072 */
2073
2074 struct mm_struct *mm = vma->vm_mm;
2075 unsigned long old_start = vma->vm_start;
2076 unsigned long old_end = vma->vm_end;
2077 unsigned long length = old_end - old_start;
2078 unsigned long new_start = old_start - shift;
2079 unsigned long new_end = old_end - shift;
2080 VMA_ITERATOR(vmi, mm, new_start);
2081 VMG_STATE(vmg, mm, &vmi, new_start, old_end, 0, vma->vm_pgoff);
2082 struct vm_area_struct *next;
2083 struct mmu_gather tlb;
2084
2085 BUG_ON(new_start > new_end);
2086
2087 /*
2088 * ensure there are no vmas between where we want to go
2089 * and where we are
2090 */
2091 if (vma != vma_next(&vmi))
2092 return -EFAULT;
2093
2094 vma_iter_prev_range(&vmi);
2095 /*
2096 * cover the whole range: [new_start, old_end)
2097 */
2098 vmg.vma = vma;
2099 if (vma_expand(&vmg))
2100 return -ENOMEM;
2101
2102 /*
2103 * move the page tables downwards, on failure we rely on
2104 * process cleanup to remove whatever mess we made.
2105 */
2106 if (length != move_page_tables(vma, old_start,
2107 vma, new_start, length, false, true))
2108 return -ENOMEM;
2109
2110 lru_add_drain();
2111 tlb_gather_mmu(&tlb, mm);
2112 next = vma_next(&vmi);
2113 if (new_end > old_start) {
2114 /*
2115 * when the old and new regions overlap clear from new_end.
2116 */
2117 free_pgd_range(&tlb, new_end, old_end, new_end,
2118 next ? next->vm_start : USER_PGTABLES_CEILING);
2119 } else {
2120 /*
2121 * otherwise, clean from old_start; this is done to not touch
2122 * the address space in [new_end, old_start) some architectures
2123 * have constraints on va-space that make this illegal (IA64) -
2124 * for the others its just a little faster.
2125 */
2126 free_pgd_range(&tlb, old_start, old_end, new_end,
2127 next ? next->vm_start : USER_PGTABLES_CEILING);
2128 }
2129 tlb_finish_mmu(&tlb);
2130
2131 vma_prev(&vmi);
2132 /* Shrink the vma to just the new range */
2133 return vma_shrink(&vmi, vma, new_start, new_end, vma->vm_pgoff);
2134}