blob: 5ecc2cf3e1d7fe27ef49787cb0909d1c3f96eebf [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
6 * Address space accounting code <alan@redhat.com>
7 */
8
9#include <linux/slab.h>
10#include <linux/mm.h>
11#include <linux/shm.h>
12#include <linux/mman.h>
13#include <linux/pagemap.h>
14#include <linux/swap.h>
15#include <linux/syscalls.h>
16#include <linux/init.h>
17#include <linux/file.h>
18#include <linux/fs.h>
19#include <linux/personality.h>
20#include <linux/security.h>
21#include <linux/hugetlb.h>
22#include <linux/profile.h>
23#include <linux/module.h>
24#include <linux/mount.h>
25#include <linux/mempolicy.h>
26#include <linux/rmap.h>
27
28#include <asm/uaccess.h>
29#include <asm/cacheflush.h>
30#include <asm/tlb.h>
31
Hugh Dickinse0da3822005-04-19 13:29:15 -070032static void unmap_region(struct mm_struct *mm,
33 struct vm_area_struct *vma, struct vm_area_struct *prev,
34 unsigned long start, unsigned long end);
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036/*
37 * WARNING: the debugging will use recursive algorithms so never enable this
38 * unless you know what you are doing.
39 */
40#undef DEBUG_MM_RB
41
42/* description of effects of mapping type and prot in current implementation.
43 * this is due to the limited x86 page protection hardware. The expected
44 * behavior is in parens:
45 *
46 * map_type prot
47 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
48 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
49 * w: (no) no w: (no) no w: (yes) yes w: (no) no
50 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
51 *
52 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
53 * w: (no) no w: (no) no w: (copy) copy w: (no) no
54 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
55 *
56 */
57pgprot_t protection_map[16] = {
58 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
59 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
60};
61
62int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
63int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070064int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065atomic_t vm_committed_space = ATOMIC_INIT(0);
66
67/*
68 * Check that a process has enough memory to allocate a new virtual
69 * mapping. 0 means there is enough memory for the allocation to
70 * succeed and -ENOMEM implies there is not.
71 *
72 * We currently support three overcommit policies, which are set via the
73 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
74 *
75 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
76 * Additional code 2002 Jul 20 by Robert Love.
77 *
78 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
79 *
80 * Note this is a helper function intended to be used by LSMs which
81 * wish to use this logic.
82 */
83int __vm_enough_memory(long pages, int cap_sys_admin)
84{
85 unsigned long free, allowed;
86
87 vm_acct_memory(pages);
88
89 /*
90 * Sometimes we want to use more memory than we have
91 */
92 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
93 return 0;
94
95 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
96 unsigned long n;
97
98 free = get_page_cache_size();
99 free += nr_swap_pages;
100
101 /*
102 * Any slabs which are created with the
103 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
104 * which are reclaimable, under pressure. The dentry
105 * cache and most inode caches should fall into this
106 */
107 free += atomic_read(&slab_reclaim_pages);
108
109 /*
110 * Leave the last 3% for root
111 */
112 if (!cap_sys_admin)
113 free -= free / 32;
114
115 if (free > pages)
116 return 0;
117
118 /*
119 * nr_free_pages() is very expensive on large systems,
120 * only call if we're about to fail.
121 */
122 n = nr_free_pages();
123 if (!cap_sys_admin)
124 n -= n / 32;
125 free += n;
126
127 if (free > pages)
128 return 0;
129 vm_unacct_memory(pages);
130 return -ENOMEM;
131 }
132
133 allowed = (totalram_pages - hugetlb_total_pages())
134 * sysctl_overcommit_ratio / 100;
135 /*
136 * Leave the last 3% for root
137 */
138 if (!cap_sys_admin)
139 allowed -= allowed / 32;
140 allowed += total_swap_pages;
141
142 /* Don't let a single process grow too big:
143 leave 3% of the size of this process for other processes */
144 allowed -= current->mm->total_vm / 32;
145
Simon Derr2f60f8d2005-08-04 19:52:03 -0700146 /*
147 * cast `allowed' as a signed long because vm_committed_space
148 * sometimes has a negative value
149 */
150 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 return 0;
152
153 vm_unacct_memory(pages);
154
155 return -ENOMEM;
156}
157
158EXPORT_SYMBOL(sysctl_overcommit_memory);
159EXPORT_SYMBOL(sysctl_overcommit_ratio);
160EXPORT_SYMBOL(sysctl_max_map_count);
161EXPORT_SYMBOL(vm_committed_space);
162EXPORT_SYMBOL(__vm_enough_memory);
163
164/*
165 * Requires inode->i_mapping->i_mmap_lock
166 */
167static void __remove_shared_vm_struct(struct vm_area_struct *vma,
168 struct file *file, struct address_space *mapping)
169{
170 if (vma->vm_flags & VM_DENYWRITE)
171 atomic_inc(&file->f_dentry->d_inode->i_writecount);
172 if (vma->vm_flags & VM_SHARED)
173 mapping->i_mmap_writable--;
174
175 flush_dcache_mmap_lock(mapping);
176 if (unlikely(vma->vm_flags & VM_NONLINEAR))
177 list_del_init(&vma->shared.vm_set.list);
178 else
179 vma_prio_tree_remove(vma, &mapping->i_mmap);
180 flush_dcache_mmap_unlock(mapping);
181}
182
183/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700184 * Unlink a file-based vm structure from its prio_tree, to hide
185 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700187void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188{
189 struct file *file = vma->vm_file;
190
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 if (file) {
192 struct address_space *mapping = file->f_mapping;
193 spin_lock(&mapping->i_mmap_lock);
194 __remove_shared_vm_struct(vma, file, mapping);
195 spin_unlock(&mapping->i_mmap_lock);
196 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700197}
198
199/*
200 * Close a vm structure and free it, returning the next.
201 */
202static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
203{
204 struct vm_area_struct *next = vma->vm_next;
205
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700206 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (vma->vm_ops && vma->vm_ops->close)
208 vma->vm_ops->close(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700209 if (vma->vm_file)
210 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 mpol_free(vma_policy(vma));
212 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700213 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216asmlinkage unsigned long sys_brk(unsigned long brk)
217{
218 unsigned long rlim, retval;
219 unsigned long newbrk, oldbrk;
220 struct mm_struct *mm = current->mm;
221
222 down_write(&mm->mmap_sem);
223
224 if (brk < mm->end_code)
225 goto out;
226 newbrk = PAGE_ALIGN(brk);
227 oldbrk = PAGE_ALIGN(mm->brk);
228 if (oldbrk == newbrk)
229 goto set_brk;
230
231 /* Always allow shrinking brk. */
232 if (brk <= mm->brk) {
233 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
234 goto set_brk;
235 goto out;
236 }
237
238 /* Check against rlimit.. */
239 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
240 if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
241 goto out;
242
243 /* Check against existing mmap mappings. */
244 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
245 goto out;
246
247 /* Ok, looks good - let it rip. */
248 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
249 goto out;
250set_brk:
251 mm->brk = brk;
252out:
253 retval = mm->brk;
254 up_write(&mm->mmap_sem);
255 return retval;
256}
257
258#ifdef DEBUG_MM_RB
259static int browse_rb(struct rb_root *root)
260{
261 int i = 0, j;
262 struct rb_node *nd, *pn = NULL;
263 unsigned long prev = 0, pend = 0;
264
265 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
266 struct vm_area_struct *vma;
267 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
268 if (vma->vm_start < prev)
269 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
270 if (vma->vm_start < pend)
271 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
272 if (vma->vm_start > vma->vm_end)
273 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
274 i++;
275 pn = nd;
276 }
277 j = 0;
278 for (nd = pn; nd; nd = rb_prev(nd)) {
279 j++;
280 }
281 if (i != j)
282 printk("backwards %d, forwards %d\n", j, i), i = 0;
283 return i;
284}
285
286void validate_mm(struct mm_struct *mm)
287{
288 int bug = 0;
289 int i = 0;
290 struct vm_area_struct *tmp = mm->mmap;
291 while (tmp) {
292 tmp = tmp->vm_next;
293 i++;
294 }
295 if (i != mm->map_count)
296 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
297 i = browse_rb(&mm->mm_rb);
298 if (i != mm->map_count)
299 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
300 if (bug)
301 BUG();
302}
303#else
304#define validate_mm(mm) do { } while (0)
305#endif
306
307static struct vm_area_struct *
308find_vma_prepare(struct mm_struct *mm, unsigned long addr,
309 struct vm_area_struct **pprev, struct rb_node ***rb_link,
310 struct rb_node ** rb_parent)
311{
312 struct vm_area_struct * vma;
313 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
314
315 __rb_link = &mm->mm_rb.rb_node;
316 rb_prev = __rb_parent = NULL;
317 vma = NULL;
318
319 while (*__rb_link) {
320 struct vm_area_struct *vma_tmp;
321
322 __rb_parent = *__rb_link;
323 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
324
325 if (vma_tmp->vm_end > addr) {
326 vma = vma_tmp;
327 if (vma_tmp->vm_start <= addr)
328 return vma;
329 __rb_link = &__rb_parent->rb_left;
330 } else {
331 rb_prev = __rb_parent;
332 __rb_link = &__rb_parent->rb_right;
333 }
334 }
335
336 *pprev = NULL;
337 if (rb_prev)
338 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
339 *rb_link = __rb_link;
340 *rb_parent = __rb_parent;
341 return vma;
342}
343
344static inline void
345__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
346 struct vm_area_struct *prev, struct rb_node *rb_parent)
347{
348 if (prev) {
349 vma->vm_next = prev->vm_next;
350 prev->vm_next = vma;
351 } else {
352 mm->mmap = vma;
353 if (rb_parent)
354 vma->vm_next = rb_entry(rb_parent,
355 struct vm_area_struct, vm_rb);
356 else
357 vma->vm_next = NULL;
358 }
359}
360
361void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
362 struct rb_node **rb_link, struct rb_node *rb_parent)
363{
364 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
365 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
366}
367
368static inline void __vma_link_file(struct vm_area_struct *vma)
369{
370 struct file * file;
371
372 file = vma->vm_file;
373 if (file) {
374 struct address_space *mapping = file->f_mapping;
375
376 if (vma->vm_flags & VM_DENYWRITE)
377 atomic_dec(&file->f_dentry->d_inode->i_writecount);
378 if (vma->vm_flags & VM_SHARED)
379 mapping->i_mmap_writable++;
380
381 flush_dcache_mmap_lock(mapping);
382 if (unlikely(vma->vm_flags & VM_NONLINEAR))
383 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
384 else
385 vma_prio_tree_insert(vma, &mapping->i_mmap);
386 flush_dcache_mmap_unlock(mapping);
387 }
388}
389
390static void
391__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
392 struct vm_area_struct *prev, struct rb_node **rb_link,
393 struct rb_node *rb_parent)
394{
395 __vma_link_list(mm, vma, prev, rb_parent);
396 __vma_link_rb(mm, vma, rb_link, rb_parent);
397 __anon_vma_link(vma);
398}
399
400static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
401 struct vm_area_struct *prev, struct rb_node **rb_link,
402 struct rb_node *rb_parent)
403{
404 struct address_space *mapping = NULL;
405
406 if (vma->vm_file)
407 mapping = vma->vm_file->f_mapping;
408
409 if (mapping) {
410 spin_lock(&mapping->i_mmap_lock);
411 vma->vm_truncate_count = mapping->truncate_count;
412 }
413 anon_vma_lock(vma);
414
415 __vma_link(mm, vma, prev, rb_link, rb_parent);
416 __vma_link_file(vma);
417
418 anon_vma_unlock(vma);
419 if (mapping)
420 spin_unlock(&mapping->i_mmap_lock);
421
422 mm->map_count++;
423 validate_mm(mm);
424}
425
426/*
427 * Helper for vma_adjust in the split_vma insert case:
428 * insert vm structure into list and rbtree and anon_vma,
429 * but it has already been inserted into prio_tree earlier.
430 */
431static void
432__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
433{
434 struct vm_area_struct * __vma, * prev;
435 struct rb_node ** rb_link, * rb_parent;
436
437 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
438 if (__vma && __vma->vm_start < vma->vm_end)
439 BUG();
440 __vma_link(mm, vma, prev, rb_link, rb_parent);
441 mm->map_count++;
442}
443
444static inline void
445__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
446 struct vm_area_struct *prev)
447{
448 prev->vm_next = vma->vm_next;
449 rb_erase(&vma->vm_rb, &mm->mm_rb);
450 if (mm->mmap_cache == vma)
451 mm->mmap_cache = prev;
452}
453
454/*
455 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
456 * is already present in an i_mmap tree without adjusting the tree.
457 * The following helper function should be used when such adjustments
458 * are necessary. The "insert" vma (if any) is to be inserted
459 * before we drop the necessary locks.
460 */
461void vma_adjust(struct vm_area_struct *vma, unsigned long start,
462 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
463{
464 struct mm_struct *mm = vma->vm_mm;
465 struct vm_area_struct *next = vma->vm_next;
466 struct vm_area_struct *importer = NULL;
467 struct address_space *mapping = NULL;
468 struct prio_tree_root *root = NULL;
469 struct file *file = vma->vm_file;
470 struct anon_vma *anon_vma = NULL;
471 long adjust_next = 0;
472 int remove_next = 0;
473
474 if (next && !insert) {
475 if (end >= next->vm_end) {
476 /*
477 * vma expands, overlapping all the next, and
478 * perhaps the one after too (mprotect case 6).
479 */
480again: remove_next = 1 + (end > next->vm_end);
481 end = next->vm_end;
482 anon_vma = next->anon_vma;
483 importer = vma;
484 } else if (end > next->vm_start) {
485 /*
486 * vma expands, overlapping part of the next:
487 * mprotect case 5 shifting the boundary up.
488 */
489 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
490 anon_vma = next->anon_vma;
491 importer = vma;
492 } else if (end < vma->vm_end) {
493 /*
494 * vma shrinks, and !insert tells it's not
495 * split_vma inserting another: so it must be
496 * mprotect case 4 shifting the boundary down.
497 */
498 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
499 anon_vma = next->anon_vma;
500 importer = next;
501 }
502 }
503
504 if (file) {
505 mapping = file->f_mapping;
506 if (!(vma->vm_flags & VM_NONLINEAR))
507 root = &mapping->i_mmap;
508 spin_lock(&mapping->i_mmap_lock);
509 if (importer &&
510 vma->vm_truncate_count != next->vm_truncate_count) {
511 /*
512 * unmap_mapping_range might be in progress:
513 * ensure that the expanding vma is rescanned.
514 */
515 importer->vm_truncate_count = 0;
516 }
517 if (insert) {
518 insert->vm_truncate_count = vma->vm_truncate_count;
519 /*
520 * Put into prio_tree now, so instantiated pages
521 * are visible to arm/parisc __flush_dcache_page
522 * throughout; but we cannot insert into address
523 * space until vma start or end is updated.
524 */
525 __vma_link_file(insert);
526 }
527 }
528
529 /*
530 * When changing only vma->vm_end, we don't really need
531 * anon_vma lock: but is that case worth optimizing out?
532 */
533 if (vma->anon_vma)
534 anon_vma = vma->anon_vma;
535 if (anon_vma) {
536 spin_lock(&anon_vma->lock);
537 /*
538 * Easily overlooked: when mprotect shifts the boundary,
539 * make sure the expanding vma has anon_vma set if the
540 * shrinking vma had, to cover any anon pages imported.
541 */
542 if (importer && !importer->anon_vma) {
543 importer->anon_vma = anon_vma;
544 __anon_vma_link(importer);
545 }
546 }
547
548 if (root) {
549 flush_dcache_mmap_lock(mapping);
550 vma_prio_tree_remove(vma, root);
551 if (adjust_next)
552 vma_prio_tree_remove(next, root);
553 }
554
555 vma->vm_start = start;
556 vma->vm_end = end;
557 vma->vm_pgoff = pgoff;
558 if (adjust_next) {
559 next->vm_start += adjust_next << PAGE_SHIFT;
560 next->vm_pgoff += adjust_next;
561 }
562
563 if (root) {
564 if (adjust_next)
565 vma_prio_tree_insert(next, root);
566 vma_prio_tree_insert(vma, root);
567 flush_dcache_mmap_unlock(mapping);
568 }
569
570 if (remove_next) {
571 /*
572 * vma_merge has merged next into vma, and needs
573 * us to remove next before dropping the locks.
574 */
575 __vma_unlink(mm, next, vma);
576 if (file)
577 __remove_shared_vm_struct(next, file, mapping);
578 if (next->anon_vma)
579 __anon_vma_merge(vma, next);
580 } else if (insert) {
581 /*
582 * split_vma has split insert from vma, and needs
583 * us to insert it before dropping the locks
584 * (it may either follow vma or precede it).
585 */
586 __insert_vm_struct(mm, insert);
587 }
588
589 if (anon_vma)
590 spin_unlock(&anon_vma->lock);
591 if (mapping)
592 spin_unlock(&mapping->i_mmap_lock);
593
594 if (remove_next) {
595 if (file)
596 fput(file);
597 mm->map_count--;
598 mpol_free(vma_policy(next));
599 kmem_cache_free(vm_area_cachep, next);
600 /*
601 * In mprotect's case 6 (see comments on vma_merge),
602 * we must remove another next too. It would clutter
603 * up the code too much to do both in one go.
604 */
605 if (remove_next == 2) {
606 next = vma->vm_next;
607 goto again;
608 }
609 }
610
611 validate_mm(mm);
612}
613
614/*
615 * If the vma has a ->close operation then the driver probably needs to release
616 * per-vma resources, so we don't attempt to merge those.
617 */
618#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED)
619
620static inline int is_mergeable_vma(struct vm_area_struct *vma,
621 struct file *file, unsigned long vm_flags)
622{
623 if (vma->vm_flags != vm_flags)
624 return 0;
625 if (vma->vm_file != file)
626 return 0;
627 if (vma->vm_ops && vma->vm_ops->close)
628 return 0;
629 return 1;
630}
631
632static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
633 struct anon_vma *anon_vma2)
634{
635 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
636}
637
638/*
639 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
640 * in front of (at a lower virtual address and file offset than) the vma.
641 *
642 * We cannot merge two vmas if they have differently assigned (non-NULL)
643 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
644 *
645 * We don't check here for the merged mmap wrapping around the end of pagecache
646 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
647 * wrap, nor mmaps which cover the final page at index -1UL.
648 */
649static int
650can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
651 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
652{
653 if (is_mergeable_vma(vma, file, vm_flags) &&
654 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
655 if (vma->vm_pgoff == vm_pgoff)
656 return 1;
657 }
658 return 0;
659}
660
661/*
662 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
663 * beyond (at a higher virtual address and file offset than) the vma.
664 *
665 * We cannot merge two vmas if they have differently assigned (non-NULL)
666 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
667 */
668static int
669can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
670 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
671{
672 if (is_mergeable_vma(vma, file, vm_flags) &&
673 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
674 pgoff_t vm_pglen;
675 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
676 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
677 return 1;
678 }
679 return 0;
680}
681
682/*
683 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
684 * whether that can be merged with its predecessor or its successor.
685 * Or both (it neatly fills a hole).
686 *
687 * In most cases - when called for mmap, brk or mremap - [addr,end) is
688 * certain not to be mapped by the time vma_merge is called; but when
689 * called for mprotect, it is certain to be already mapped (either at
690 * an offset within prev, or at the start of next), and the flags of
691 * this area are about to be changed to vm_flags - and the no-change
692 * case has already been eliminated.
693 *
694 * The following mprotect cases have to be considered, where AAAA is
695 * the area passed down from mprotect_fixup, never extending beyond one
696 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
697 *
698 * AAAA AAAA AAAA AAAA
699 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
700 * cannot merge might become might become might become
701 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
702 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
703 * mremap move: PPPPNNNNNNNN 8
704 * AAAA
705 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
706 * might become case 1 below case 2 below case 3 below
707 *
708 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
709 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
710 */
711struct vm_area_struct *vma_merge(struct mm_struct *mm,
712 struct vm_area_struct *prev, unsigned long addr,
713 unsigned long end, unsigned long vm_flags,
714 struct anon_vma *anon_vma, struct file *file,
715 pgoff_t pgoff, struct mempolicy *policy)
716{
717 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
718 struct vm_area_struct *area, *next;
719
720 /*
721 * We later require that vma->vm_flags == vm_flags,
722 * so this tests vma->vm_flags & VM_SPECIAL, too.
723 */
724 if (vm_flags & VM_SPECIAL)
725 return NULL;
726
727 if (prev)
728 next = prev->vm_next;
729 else
730 next = mm->mmap;
731 area = next;
732 if (next && next->vm_end == end) /* cases 6, 7, 8 */
733 next = next->vm_next;
734
735 /*
736 * Can it merge with the predecessor?
737 */
738 if (prev && prev->vm_end == addr &&
739 mpol_equal(vma_policy(prev), policy) &&
740 can_vma_merge_after(prev, vm_flags,
741 anon_vma, file, pgoff)) {
742 /*
743 * OK, it can. Can we now merge in the successor as well?
744 */
745 if (next && end == next->vm_start &&
746 mpol_equal(policy, vma_policy(next)) &&
747 can_vma_merge_before(next, vm_flags,
748 anon_vma, file, pgoff+pglen) &&
749 is_mergeable_anon_vma(prev->anon_vma,
750 next->anon_vma)) {
751 /* cases 1, 6 */
752 vma_adjust(prev, prev->vm_start,
753 next->vm_end, prev->vm_pgoff, NULL);
754 } else /* cases 2, 5, 7 */
755 vma_adjust(prev, prev->vm_start,
756 end, prev->vm_pgoff, NULL);
757 return prev;
758 }
759
760 /*
761 * Can this new request be merged in front of next?
762 */
763 if (next && end == next->vm_start &&
764 mpol_equal(policy, vma_policy(next)) &&
765 can_vma_merge_before(next, vm_flags,
766 anon_vma, file, pgoff+pglen)) {
767 if (prev && addr < prev->vm_end) /* case 4 */
768 vma_adjust(prev, prev->vm_start,
769 addr, prev->vm_pgoff, NULL);
770 else /* cases 3, 8 */
771 vma_adjust(area, addr, next->vm_end,
772 next->vm_pgoff - pglen, NULL);
773 return area;
774 }
775
776 return NULL;
777}
778
779/*
780 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
781 * neighbouring vmas for a suitable anon_vma, before it goes off
782 * to allocate a new anon_vma. It checks because a repetitive
783 * sequence of mprotects and faults may otherwise lead to distinct
784 * anon_vmas being allocated, preventing vma merge in subsequent
785 * mprotect.
786 */
787struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
788{
789 struct vm_area_struct *near;
790 unsigned long vm_flags;
791
792 near = vma->vm_next;
793 if (!near)
794 goto try_prev;
795
796 /*
797 * Since only mprotect tries to remerge vmas, match flags
798 * which might be mprotected into each other later on.
799 * Neither mlock nor madvise tries to remerge at present,
800 * so leave their flags as obstructing a merge.
801 */
802 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
803 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
804
805 if (near->anon_vma && vma->vm_end == near->vm_start &&
806 mpol_equal(vma_policy(vma), vma_policy(near)) &&
807 can_vma_merge_before(near, vm_flags,
808 NULL, vma->vm_file, vma->vm_pgoff +
809 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
810 return near->anon_vma;
811try_prev:
812 /*
813 * It is potentially slow to have to call find_vma_prev here.
814 * But it's only on the first write fault on the vma, not
815 * every time, and we could devise a way to avoid it later
816 * (e.g. stash info in next's anon_vma_node when assigning
817 * an anon_vma, or when trying vma_merge). Another time.
818 */
819 if (find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma)
820 BUG();
821 if (!near)
822 goto none;
823
824 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
825 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
826
827 if (near->anon_vma && near->vm_end == vma->vm_start &&
828 mpol_equal(vma_policy(near), vma_policy(vma)) &&
829 can_vma_merge_after(near, vm_flags,
830 NULL, vma->vm_file, vma->vm_pgoff))
831 return near->anon_vma;
832none:
833 /*
834 * There's no absolute need to look only at touching neighbours:
835 * we could search further afield for "compatible" anon_vmas.
836 * But it would probably just be a waste of time searching,
837 * or lead to too many vmas hanging off the same anon_vma.
838 * We're trying to allow mprotect remerging later on,
839 * not trying to minimize memory used for anon_vmas.
840 */
841 return NULL;
842}
843
844#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700845void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 struct file *file, long pages)
847{
848 const unsigned long stack_flags
849 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
850
851#ifdef CONFIG_HUGETLB
852 if (flags & VM_HUGETLB) {
853 if (!(flags & VM_DONTCOPY))
854 mm->shared_vm += pages;
855 return;
856 }
857#endif /* CONFIG_HUGETLB */
858
859 if (file) {
860 mm->shared_vm += pages;
861 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
862 mm->exec_vm += pages;
863 } else if (flags & stack_flags)
864 mm->stack_vm += pages;
865 if (flags & (VM_RESERVED|VM_IO))
866 mm->reserved_vm += pages;
867}
868#endif /* CONFIG_PROC_FS */
869
870/*
871 * The caller must hold down_write(current->mm->mmap_sem).
872 */
873
874unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
875 unsigned long len, unsigned long prot,
876 unsigned long flags, unsigned long pgoff)
877{
878 struct mm_struct * mm = current->mm;
879 struct vm_area_struct * vma, * prev;
880 struct inode *inode;
881 unsigned int vm_flags;
882 int correct_wcount = 0;
883 int error;
884 struct rb_node ** rb_link, * rb_parent;
885 int accountable = 1;
886 unsigned long charged = 0, reqprot = prot;
887
888 if (file) {
889 if (is_file_hugepages(file))
890 accountable = 0;
891
892 if (!file->f_op || !file->f_op->mmap)
893 return -ENODEV;
894
895 if ((prot & PROT_EXEC) &&
896 (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
897 return -EPERM;
898 }
899 /*
900 * Does the application expect PROT_READ to imply PROT_EXEC?
901 *
902 * (the exception is when the underlying filesystem is noexec
903 * mounted, in which case we dont add PROT_EXEC.)
904 */
905 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
906 if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)))
907 prot |= PROT_EXEC;
908
909 if (!len)
910 return -EINVAL;
911
912 /* Careful about overflows.. */
913 len = PAGE_ALIGN(len);
914 if (!len || len > TASK_SIZE)
915 return -ENOMEM;
916
917 /* offset overflow? */
918 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
919 return -EOVERFLOW;
920
921 /* Too many mappings? */
922 if (mm->map_count > sysctl_max_map_count)
923 return -ENOMEM;
924
925 /* Obtain the address to map to. we verify (or select) it and ensure
926 * that it represents a valid section of the address space.
927 */
928 addr = get_unmapped_area(file, addr, len, pgoff, flags);
929 if (addr & ~PAGE_MASK)
930 return addr;
931
932 /* Do simple checking here so the lower-level routines won't have
933 * to. we assume access permissions have been handled by the open
934 * of the memory object, so we don't do any here.
935 */
936 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
937 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
938
939 if (flags & MAP_LOCKED) {
940 if (!can_do_mlock())
941 return -EPERM;
942 vm_flags |= VM_LOCKED;
943 }
944 /* mlock MCL_FUTURE? */
945 if (vm_flags & VM_LOCKED) {
946 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700947 locked = len >> PAGE_SHIFT;
948 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700950 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
952 return -EAGAIN;
953 }
954
955 inode = file ? file->f_dentry->d_inode : NULL;
956
957 if (file) {
958 switch (flags & MAP_TYPE) {
959 case MAP_SHARED:
960 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
961 return -EACCES;
962
963 /*
964 * Make sure we don't allow writing to an append-only
965 * file..
966 */
967 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
968 return -EACCES;
969
970 /*
971 * Make sure there are no mandatory locks on the file.
972 */
973 if (locks_verify_locked(inode))
974 return -EAGAIN;
975
976 vm_flags |= VM_SHARED | VM_MAYSHARE;
977 if (!(file->f_mode & FMODE_WRITE))
978 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
979
980 /* fall through */
981 case MAP_PRIVATE:
982 if (!(file->f_mode & FMODE_READ))
983 return -EACCES;
984 break;
985
986 default:
987 return -EINVAL;
988 }
989 } else {
990 switch (flags & MAP_TYPE) {
991 case MAP_SHARED:
992 vm_flags |= VM_SHARED | VM_MAYSHARE;
993 break;
994 case MAP_PRIVATE:
995 /*
996 * Set pgoff according to addr for anon_vma.
997 */
998 pgoff = addr >> PAGE_SHIFT;
999 break;
1000 default:
1001 return -EINVAL;
1002 }
1003 }
1004
1005 error = security_file_mmap(file, reqprot, prot, flags);
1006 if (error)
1007 return error;
1008
1009 /* Clear old maps */
1010 error = -ENOMEM;
1011munmap_back:
1012 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1013 if (vma && vma->vm_start < addr + len) {
1014 if (do_munmap(mm, addr, len))
1015 return -ENOMEM;
1016 goto munmap_back;
1017 }
1018
1019 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001020 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 return -ENOMEM;
1022
1023 if (accountable && (!(flags & MAP_NORESERVE) ||
1024 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1025 if (vm_flags & VM_SHARED) {
1026 /* Check memory availability in shmem_file_setup? */
1027 vm_flags |= VM_ACCOUNT;
1028 } else if (vm_flags & VM_WRITE) {
1029 /*
1030 * Private writable mapping: check memory availability
1031 */
1032 charged = len >> PAGE_SHIFT;
1033 if (security_vm_enough_memory(charged))
1034 return -ENOMEM;
1035 vm_flags |= VM_ACCOUNT;
1036 }
1037 }
1038
1039 /*
1040 * Can we just expand an old private anonymous mapping?
1041 * The VM_SHARED test is necessary because shmem_zero_setup
1042 * will create the file object for a shared anonymous map below.
1043 */
1044 if (!file && !(vm_flags & VM_SHARED) &&
1045 vma_merge(mm, prev, addr, addr + len, vm_flags,
1046 NULL, NULL, pgoff, NULL))
1047 goto out;
1048
1049 /*
1050 * Determine the object being mapped and call the appropriate
1051 * specific mapper. the address has already been validated, but
1052 * not unmapped, but the maps are removed from the list.
1053 */
1054 vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
1055 if (!vma) {
1056 error = -ENOMEM;
1057 goto unacct_error;
1058 }
1059 memset(vma, 0, sizeof(*vma));
1060
1061 vma->vm_mm = mm;
1062 vma->vm_start = addr;
1063 vma->vm_end = addr + len;
1064 vma->vm_flags = vm_flags;
1065 vma->vm_page_prot = protection_map[vm_flags & 0x0f];
1066 vma->vm_pgoff = pgoff;
1067
1068 if (file) {
1069 error = -EINVAL;
1070 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1071 goto free_vma;
1072 if (vm_flags & VM_DENYWRITE) {
1073 error = deny_write_access(file);
1074 if (error)
1075 goto free_vma;
1076 correct_wcount = 1;
1077 }
1078 vma->vm_file = file;
1079 get_file(file);
1080 error = file->f_op->mmap(file, vma);
1081 if (error)
1082 goto unmap_and_free_vma;
Nick Pigginb5810032005-10-29 18:16:12 -07001083 if ((vma->vm_flags & (VM_SHARED | VM_WRITE | VM_RESERVED))
1084 == (VM_WRITE | VM_RESERVED)) {
1085 printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
1086 "PROT_WRITE mmap of VM_RESERVED memory, which "
1087 "is deprecated. Please report this to "
1088 "linux-kernel@vger.kernel.org\n",current->comm);
1089 if (vma->vm_ops && vma->vm_ops->close)
1090 vma->vm_ops->close(vma);
1091 error = -EACCES;
1092 goto unmap_and_free_vma;
1093 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 } else if (vm_flags & VM_SHARED) {
1095 error = shmem_zero_setup(vma);
1096 if (error)
1097 goto free_vma;
1098 }
1099
1100 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1101 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1102 * that memory reservation must be checked; but that reservation
1103 * belongs to shared memory object, not to vma: so now clear it.
1104 */
1105 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1106 vma->vm_flags &= ~VM_ACCOUNT;
1107
1108 /* Can addr have changed??
1109 *
1110 * Answer: Yes, several device drivers can do it in their
1111 * f_op->mmap method. -DaveM
1112 */
1113 addr = vma->vm_start;
1114 pgoff = vma->vm_pgoff;
1115 vm_flags = vma->vm_flags;
1116
1117 if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
1118 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
1119 file = vma->vm_file;
1120 vma_link(mm, vma, prev, rb_link, rb_parent);
1121 if (correct_wcount)
1122 atomic_inc(&inode->i_writecount);
1123 } else {
1124 if (file) {
1125 if (correct_wcount)
1126 atomic_inc(&inode->i_writecount);
1127 fput(file);
1128 }
1129 mpol_free(vma_policy(vma));
1130 kmem_cache_free(vm_area_cachep, vma);
1131 }
1132out:
1133 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001134 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 if (vm_flags & VM_LOCKED) {
1136 mm->locked_vm += len >> PAGE_SHIFT;
1137 make_pages_present(addr, addr + len);
1138 }
1139 if (flags & MAP_POPULATE) {
1140 up_write(&mm->mmap_sem);
1141 sys_remap_file_pages(addr, len, 0,
1142 pgoff, flags & MAP_NONBLOCK);
1143 down_write(&mm->mmap_sem);
1144 }
1145 return addr;
1146
1147unmap_and_free_vma:
1148 if (correct_wcount)
1149 atomic_inc(&inode->i_writecount);
1150 vma->vm_file = NULL;
1151 fput(file);
1152
1153 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001154 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1155 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156free_vma:
1157 kmem_cache_free(vm_area_cachep, vma);
1158unacct_error:
1159 if (charged)
1160 vm_unacct_memory(charged);
1161 return error;
1162}
1163
1164EXPORT_SYMBOL(do_mmap_pgoff);
1165
1166/* Get an address range which is currently unmapped.
1167 * For shmat() with addr=0.
1168 *
1169 * Ugly calling convention alert:
1170 * Return value with the low bits set means error value,
1171 * ie
1172 * if (ret & ~PAGE_MASK)
1173 * error = ret;
1174 *
1175 * This function "knows" that -ENOMEM has the bits set.
1176 */
1177#ifndef HAVE_ARCH_UNMAPPED_AREA
1178unsigned long
1179arch_get_unmapped_area(struct file *filp, unsigned long addr,
1180 unsigned long len, unsigned long pgoff, unsigned long flags)
1181{
1182 struct mm_struct *mm = current->mm;
1183 struct vm_area_struct *vma;
1184 unsigned long start_addr;
1185
1186 if (len > TASK_SIZE)
1187 return -ENOMEM;
1188
1189 if (addr) {
1190 addr = PAGE_ALIGN(addr);
1191 vma = find_vma(mm, addr);
1192 if (TASK_SIZE - len >= addr &&
1193 (!vma || addr + len <= vma->vm_start))
1194 return addr;
1195 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001196 if (len > mm->cached_hole_size) {
1197 start_addr = addr = mm->free_area_cache;
1198 } else {
1199 start_addr = addr = TASK_UNMAPPED_BASE;
1200 mm->cached_hole_size = 0;
1201 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202
1203full_search:
1204 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1205 /* At this point: (!vma || addr < vma->vm_end). */
1206 if (TASK_SIZE - len < addr) {
1207 /*
1208 * Start a new search - just in case we missed
1209 * some holes.
1210 */
1211 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001212 addr = TASK_UNMAPPED_BASE;
1213 start_addr = addr;
1214 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 goto full_search;
1216 }
1217 return -ENOMEM;
1218 }
1219 if (!vma || addr + len <= vma->vm_start) {
1220 /*
1221 * Remember the place where we stopped the search:
1222 */
1223 mm->free_area_cache = addr + len;
1224 return addr;
1225 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001226 if (addr + mm->cached_hole_size < vma->vm_start)
1227 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 addr = vma->vm_end;
1229 }
1230}
1231#endif
1232
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001233void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234{
1235 /*
1236 * Is this a new hole at the lowest possible address?
1237 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001238 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1239 mm->free_area_cache = addr;
1240 mm->cached_hole_size = ~0UL;
1241 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242}
1243
1244/*
1245 * This mmap-allocator allocates new areas top-down from below the
1246 * stack's low limit (the base):
1247 */
1248#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1249unsigned long
1250arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1251 const unsigned long len, const unsigned long pgoff,
1252 const unsigned long flags)
1253{
1254 struct vm_area_struct *vma;
1255 struct mm_struct *mm = current->mm;
1256 unsigned long addr = addr0;
1257
1258 /* requested length too big for entire address space */
1259 if (len > TASK_SIZE)
1260 return -ENOMEM;
1261
1262 /* requesting a specific address */
1263 if (addr) {
1264 addr = PAGE_ALIGN(addr);
1265 vma = find_vma(mm, addr);
1266 if (TASK_SIZE - len >= addr &&
1267 (!vma || addr + len <= vma->vm_start))
1268 return addr;
1269 }
1270
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001271 /* check if free_area_cache is useful for us */
1272 if (len <= mm->cached_hole_size) {
1273 mm->cached_hole_size = 0;
1274 mm->free_area_cache = mm->mmap_base;
1275 }
1276
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 /* either no address requested or can't fit in requested address hole */
1278 addr = mm->free_area_cache;
1279
1280 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001281 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 vma = find_vma(mm, addr-len);
1283 if (!vma || addr <= vma->vm_start)
1284 /* remember the address as a hint for next time */
1285 return (mm->free_area_cache = addr-len);
1286 }
1287
Chris Wright73219d12005-06-21 17:14:52 -07001288 if (mm->mmap_base < len)
1289 goto bottomup;
1290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 addr = mm->mmap_base-len;
1292
1293 do {
1294 /*
1295 * Lookup failure means no vma is above this address,
1296 * else if new region fits below vma->vm_start,
1297 * return with success:
1298 */
1299 vma = find_vma(mm, addr);
1300 if (!vma || addr+len <= vma->vm_start)
1301 /* remember the address as a hint for next time */
1302 return (mm->free_area_cache = addr);
1303
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001304 /* remember the largest hole we saw so far */
1305 if (addr + mm->cached_hole_size < vma->vm_start)
1306 mm->cached_hole_size = vma->vm_start - addr;
1307
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 /* try just below the current vma->vm_start */
1309 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001310 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311
Chris Wright73219d12005-06-21 17:14:52 -07001312bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 /*
1314 * A failed mmap() very likely causes application failure,
1315 * so fall back to the bottom-up function here. This scenario
1316 * can happen with large stack limits and large mmap()
1317 * allocations.
1318 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001319 mm->cached_hole_size = ~0UL;
1320 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1322 /*
1323 * Restore the topdown base:
1324 */
1325 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001326 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327
1328 return addr;
1329}
1330#endif
1331
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001332void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333{
1334 /*
1335 * Is this a new hole at the highest possible address?
1336 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001337 if (addr > mm->free_area_cache)
1338 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
1340 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001341 if (mm->free_area_cache > mm->mmap_base)
1342 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343}
1344
1345unsigned long
1346get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1347 unsigned long pgoff, unsigned long flags)
1348{
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001349 unsigned long ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001351 if (!(flags & MAP_FIXED)) {
1352 unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1353
1354 get_area = current->mm->get_unmapped_area;
1355 if (file && file->f_op && file->f_op->get_unmapped_area)
1356 get_area = file->f_op->get_unmapped_area;
1357 addr = get_area(file, addr, len, pgoff, flags);
1358 if (IS_ERR_VALUE(addr))
1359 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 }
1361
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001362 if (addr > TASK_SIZE - len)
1363 return -ENOMEM;
1364 if (addr & ~PAGE_MASK)
1365 return -EINVAL;
1366 if (file && is_file_hugepages(file)) {
1367 /*
1368 * Check if the given range is hugepage aligned, and
1369 * can be made suitable for hugepages.
1370 */
1371 ret = prepare_hugepage_range(addr, len);
1372 } else {
1373 /*
1374 * Ensure that a normal request is not falling in a
1375 * reserved hugepage range. For some archs like IA-64,
1376 * there is a separate region for hugepages.
1377 */
1378 ret = is_hugepage_only_range(current->mm, addr, len);
1379 }
1380 if (ret)
1381 return -EINVAL;
1382 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383}
1384
1385EXPORT_SYMBOL(get_unmapped_area);
1386
1387/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1388struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1389{
1390 struct vm_area_struct *vma = NULL;
1391
1392 if (mm) {
1393 /* Check the cache first. */
1394 /* (Cache hit rate is typically around 35%.) */
1395 vma = mm->mmap_cache;
1396 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1397 struct rb_node * rb_node;
1398
1399 rb_node = mm->mm_rb.rb_node;
1400 vma = NULL;
1401
1402 while (rb_node) {
1403 struct vm_area_struct * vma_tmp;
1404
1405 vma_tmp = rb_entry(rb_node,
1406 struct vm_area_struct, vm_rb);
1407
1408 if (vma_tmp->vm_end > addr) {
1409 vma = vma_tmp;
1410 if (vma_tmp->vm_start <= addr)
1411 break;
1412 rb_node = rb_node->rb_left;
1413 } else
1414 rb_node = rb_node->rb_right;
1415 }
1416 if (vma)
1417 mm->mmap_cache = vma;
1418 }
1419 }
1420 return vma;
1421}
1422
1423EXPORT_SYMBOL(find_vma);
1424
1425/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1426struct vm_area_struct *
1427find_vma_prev(struct mm_struct *mm, unsigned long addr,
1428 struct vm_area_struct **pprev)
1429{
1430 struct vm_area_struct *vma = NULL, *prev = NULL;
1431 struct rb_node * rb_node;
1432 if (!mm)
1433 goto out;
1434
1435 /* Guard against addr being lower than the first VMA */
1436 vma = mm->mmap;
1437
1438 /* Go through the RB tree quickly. */
1439 rb_node = mm->mm_rb.rb_node;
1440
1441 while (rb_node) {
1442 struct vm_area_struct *vma_tmp;
1443 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1444
1445 if (addr < vma_tmp->vm_end) {
1446 rb_node = rb_node->rb_left;
1447 } else {
1448 prev = vma_tmp;
1449 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1450 break;
1451 rb_node = rb_node->rb_right;
1452 }
1453 }
1454
1455out:
1456 *pprev = prev;
1457 return prev ? prev->vm_next : vma;
1458}
1459
1460/*
1461 * Verify that the stack growth is acceptable and
1462 * update accounting. This is shared with both the
1463 * grow-up and grow-down cases.
1464 */
1465static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1466{
1467 struct mm_struct *mm = vma->vm_mm;
1468 struct rlimit *rlim = current->signal->rlim;
1469
1470 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001471 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 return -ENOMEM;
1473
1474 /* Stack limit test */
1475 if (size > rlim[RLIMIT_STACK].rlim_cur)
1476 return -ENOMEM;
1477
1478 /* mlock limit tests */
1479 if (vma->vm_flags & VM_LOCKED) {
1480 unsigned long locked;
1481 unsigned long limit;
1482 locked = mm->locked_vm + grow;
1483 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1484 if (locked > limit && !capable(CAP_IPC_LOCK))
1485 return -ENOMEM;
1486 }
1487
1488 /*
1489 * Overcommit.. This must be the final test, as it will
1490 * update security statistics.
1491 */
1492 if (security_vm_enough_memory(grow))
1493 return -ENOMEM;
1494
1495 /* Ok, everything looks good - let it rip */
1496 mm->total_vm += grow;
1497 if (vma->vm_flags & VM_LOCKED)
1498 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001499 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 return 0;
1501}
1502
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001503#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001505 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1506 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001508#ifdef CONFIG_STACK_GROWSUP
1509static inline
1510#endif
1511int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512{
1513 int error;
1514
1515 if (!(vma->vm_flags & VM_GROWSUP))
1516 return -EFAULT;
1517
1518 /*
1519 * We must make sure the anon_vma is allocated
1520 * so that the anon_vma locking is not a noop.
1521 */
1522 if (unlikely(anon_vma_prepare(vma)))
1523 return -ENOMEM;
1524 anon_vma_lock(vma);
1525
1526 /*
1527 * vma->vm_start/vm_end cannot change under us because the caller
1528 * is required to hold the mmap_sem in read mode. We need the
1529 * anon_vma lock to serialize against concurrent expand_stacks.
1530 */
1531 address += 4 + PAGE_SIZE - 1;
1532 address &= PAGE_MASK;
1533 error = 0;
1534
1535 /* Somebody else might have raced and expanded it already */
1536 if (address > vma->vm_end) {
1537 unsigned long size, grow;
1538
1539 size = address - vma->vm_start;
1540 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1541
1542 error = acct_stack_growth(vma, size, grow);
1543 if (!error)
1544 vma->vm_end = address;
1545 }
1546 anon_vma_unlock(vma);
1547 return error;
1548}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001549#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1550
1551#ifdef CONFIG_STACK_GROWSUP
1552int expand_stack(struct vm_area_struct *vma, unsigned long address)
1553{
1554 return expand_upwards(vma, address);
1555}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556
1557struct vm_area_struct *
1558find_extend_vma(struct mm_struct *mm, unsigned long addr)
1559{
1560 struct vm_area_struct *vma, *prev;
1561
1562 addr &= PAGE_MASK;
1563 vma = find_vma_prev(mm, addr, &prev);
1564 if (vma && (vma->vm_start <= addr))
1565 return vma;
1566 if (!prev || expand_stack(prev, addr))
1567 return NULL;
1568 if (prev->vm_flags & VM_LOCKED) {
1569 make_pages_present(addr, prev->vm_end);
1570 }
1571 return prev;
1572}
1573#else
1574/*
1575 * vma is the first one with address < vma->vm_start. Have to extend vma.
1576 */
1577int expand_stack(struct vm_area_struct *vma, unsigned long address)
1578{
1579 int error;
1580
1581 /*
1582 * We must make sure the anon_vma is allocated
1583 * so that the anon_vma locking is not a noop.
1584 */
1585 if (unlikely(anon_vma_prepare(vma)))
1586 return -ENOMEM;
1587 anon_vma_lock(vma);
1588
1589 /*
1590 * vma->vm_start/vm_end cannot change under us because the caller
1591 * is required to hold the mmap_sem in read mode. We need the
1592 * anon_vma lock to serialize against concurrent expand_stacks.
1593 */
1594 address &= PAGE_MASK;
1595 error = 0;
1596
1597 /* Somebody else might have raced and expanded it already */
1598 if (address < vma->vm_start) {
1599 unsigned long size, grow;
1600
1601 size = vma->vm_end - address;
1602 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1603
1604 error = acct_stack_growth(vma, size, grow);
1605 if (!error) {
1606 vma->vm_start = address;
1607 vma->vm_pgoff -= grow;
1608 }
1609 }
1610 anon_vma_unlock(vma);
1611 return error;
1612}
1613
1614struct vm_area_struct *
1615find_extend_vma(struct mm_struct * mm, unsigned long addr)
1616{
1617 struct vm_area_struct * vma;
1618 unsigned long start;
1619
1620 addr &= PAGE_MASK;
1621 vma = find_vma(mm,addr);
1622 if (!vma)
1623 return NULL;
1624 if (vma->vm_start <= addr)
1625 return vma;
1626 if (!(vma->vm_flags & VM_GROWSDOWN))
1627 return NULL;
1628 start = vma->vm_start;
1629 if (expand_stack(vma, addr))
1630 return NULL;
1631 if (vma->vm_flags & VM_LOCKED) {
1632 make_pages_present(addr, start);
1633 }
1634 return vma;
1635}
1636#endif
1637
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001639 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001641 *
1642 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001644static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001646 /* Update high watermark before we lower total_vm */
1647 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001649 long nrpages = vma_pages(vma);
1650
1651 mm->total_vm -= nrpages;
1652 if (vma->vm_flags & VM_LOCKED)
1653 mm->locked_vm -= nrpages;
1654 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001655 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001656 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657 validate_mm(mm);
1658}
1659
1660/*
1661 * Get rid of page table information in the indicated region.
1662 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001663 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001664 */
1665static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001666 struct vm_area_struct *vma, struct vm_area_struct *prev,
1667 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001669 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 struct mmu_gather *tlb;
1671 unsigned long nr_accounted = 0;
1672
1673 lru_add_drain();
1674 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001675 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001676 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001678 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001679 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 tlb_finish_mmu(tlb, start, end);
1681}
1682
1683/*
1684 * Create a list of vma's touched by the unmap, removing them from the mm's
1685 * vma list as we go..
1686 */
1687static void
1688detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1689 struct vm_area_struct *prev, unsigned long end)
1690{
1691 struct vm_area_struct **insertion_point;
1692 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001693 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694
1695 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1696 do {
1697 rb_erase(&vma->vm_rb, &mm->mm_rb);
1698 mm->map_count--;
1699 tail_vma = vma;
1700 vma = vma->vm_next;
1701 } while (vma && vma->vm_start < end);
1702 *insertion_point = vma;
1703 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001704 if (mm->unmap_area == arch_unmap_area)
1705 addr = prev ? prev->vm_end : mm->mmap_base;
1706 else
1707 addr = vma ? vma->vm_start : mm->mmap_base;
1708 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 mm->mmap_cache = NULL; /* Kill the cache. */
1710}
1711
1712/*
1713 * Split a vma into two pieces at address 'addr', a new vma is allocated
1714 * either for the first part or the the tail.
1715 */
1716int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1717 unsigned long addr, int new_below)
1718{
1719 struct mempolicy *pol;
1720 struct vm_area_struct *new;
1721
1722 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1723 return -EINVAL;
1724
1725 if (mm->map_count >= sysctl_max_map_count)
1726 return -ENOMEM;
1727
1728 new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
1729 if (!new)
1730 return -ENOMEM;
1731
1732 /* most fields are the same, copy all, and then fixup */
1733 *new = *vma;
1734
1735 if (new_below)
1736 new->vm_end = addr;
1737 else {
1738 new->vm_start = addr;
1739 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1740 }
1741
1742 pol = mpol_copy(vma_policy(vma));
1743 if (IS_ERR(pol)) {
1744 kmem_cache_free(vm_area_cachep, new);
1745 return PTR_ERR(pol);
1746 }
1747 vma_set_policy(new, pol);
1748
1749 if (new->vm_file)
1750 get_file(new->vm_file);
1751
1752 if (new->vm_ops && new->vm_ops->open)
1753 new->vm_ops->open(new);
1754
1755 if (new_below)
1756 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1757 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1758 else
1759 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1760
1761 return 0;
1762}
1763
1764/* Munmap is split into 2 main parts -- this part which finds
1765 * what needs doing, and the areas themselves, which do the
1766 * work. This now handles partial unmappings.
1767 * Jeremy Fitzhardinge <jeremy@goop.org>
1768 */
1769int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1770{
1771 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001772 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773
1774 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1775 return -EINVAL;
1776
1777 if ((len = PAGE_ALIGN(len)) == 0)
1778 return -EINVAL;
1779
1780 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001781 vma = find_vma_prev(mm, start, &prev);
1782 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001784 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785
1786 /* if it doesn't overlap, we have nothing.. */
1787 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001788 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 return 0;
1790
1791 /*
1792 * If we need to split any vma, do it now to save pain later.
1793 *
1794 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1795 * unmapped vm_area_struct will remain in use: so lower split_vma
1796 * places tmp vma above, and higher split_vma places tmp vma below.
1797 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001798 if (start > vma->vm_start) {
1799 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800 if (error)
1801 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001802 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 }
1804
1805 /* Does it split the last one? */
1806 last = find_vma(mm, end);
1807 if (last && end > last->vm_start) {
1808 int error = split_vma(mm, last, end, 1);
1809 if (error)
1810 return error;
1811 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001812 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813
1814 /*
1815 * Remove the vma's, and unmap the actual pages
1816 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001817 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1818 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819
1820 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001821 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822
1823 return 0;
1824}
1825
1826EXPORT_SYMBOL(do_munmap);
1827
1828asmlinkage long sys_munmap(unsigned long addr, size_t len)
1829{
1830 int ret;
1831 struct mm_struct *mm = current->mm;
1832
1833 profile_munmap(addr);
1834
1835 down_write(&mm->mmap_sem);
1836 ret = do_munmap(mm, addr, len);
1837 up_write(&mm->mmap_sem);
1838 return ret;
1839}
1840
1841static inline void verify_mm_writelocked(struct mm_struct *mm)
1842{
1843#ifdef CONFIG_DEBUG_KERNEL
1844 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1845 WARN_ON(1);
1846 up_read(&mm->mmap_sem);
1847 }
1848#endif
1849}
1850
1851/*
1852 * this is really a simplified "do_mmap". it only handles
1853 * anonymous maps. eventually we may be able to do some
1854 * brk-specific accounting here.
1855 */
1856unsigned long do_brk(unsigned long addr, unsigned long len)
1857{
1858 struct mm_struct * mm = current->mm;
1859 struct vm_area_struct * vma, * prev;
1860 unsigned long flags;
1861 struct rb_node ** rb_link, * rb_parent;
1862 pgoff_t pgoff = addr >> PAGE_SHIFT;
1863
1864 len = PAGE_ALIGN(len);
1865 if (!len)
1866 return addr;
1867
1868 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1869 return -EINVAL;
1870
1871 /*
1872 * mlock MCL_FUTURE?
1873 */
1874 if (mm->def_flags & VM_LOCKED) {
1875 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001876 locked = len >> PAGE_SHIFT;
1877 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001879 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1881 return -EAGAIN;
1882 }
1883
1884 /*
1885 * mm->mmap_sem is required to protect against another thread
1886 * changing the mappings in case we sleep.
1887 */
1888 verify_mm_writelocked(mm);
1889
1890 /*
1891 * Clear old maps. this also does some error checking for us
1892 */
1893 munmap_back:
1894 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1895 if (vma && vma->vm_start < addr + len) {
1896 if (do_munmap(mm, addr, len))
1897 return -ENOMEM;
1898 goto munmap_back;
1899 }
1900
1901 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001902 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903 return -ENOMEM;
1904
1905 if (mm->map_count > sysctl_max_map_count)
1906 return -ENOMEM;
1907
1908 if (security_vm_enough_memory(len >> PAGE_SHIFT))
1909 return -ENOMEM;
1910
1911 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1912
1913 /* Can we just expand an old private anonymous mapping? */
1914 if (vma_merge(mm, prev, addr, addr + len, flags,
1915 NULL, NULL, pgoff, NULL))
1916 goto out;
1917
1918 /*
1919 * create a vma struct for an anonymous mapping
1920 */
1921 vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
1922 if (!vma) {
1923 vm_unacct_memory(len >> PAGE_SHIFT);
1924 return -ENOMEM;
1925 }
1926 memset(vma, 0, sizeof(*vma));
1927
1928 vma->vm_mm = mm;
1929 vma->vm_start = addr;
1930 vma->vm_end = addr + len;
1931 vma->vm_pgoff = pgoff;
1932 vma->vm_flags = flags;
1933 vma->vm_page_prot = protection_map[flags & 0x0f];
1934 vma_link(mm, vma, prev, rb_link, rb_parent);
1935out:
1936 mm->total_vm += len >> PAGE_SHIFT;
1937 if (flags & VM_LOCKED) {
1938 mm->locked_vm += len >> PAGE_SHIFT;
1939 make_pages_present(addr, addr + len);
1940 }
1941 return addr;
1942}
1943
1944EXPORT_SYMBOL(do_brk);
1945
1946/* Release all mmaps. */
1947void exit_mmap(struct mm_struct *mm)
1948{
1949 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07001950 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07001952 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953
1954 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07001956 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001957 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001958 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07001959 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001960 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001961 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001962 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07001965 * Walk the list again, actually closing and freeing it,
1966 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001968 while (vma)
1969 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07001970
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001971 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972}
1973
1974/* Insert vm structure into process list sorted by address
1975 * and into the inode's i_mmap tree. If vm_file is non-NULL
1976 * then i_mmap_lock is taken here.
1977 */
1978int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
1979{
1980 struct vm_area_struct * __vma, * prev;
1981 struct rb_node ** rb_link, * rb_parent;
1982
1983 /*
1984 * The vm_pgoff of a purely anonymous vma should be irrelevant
1985 * until its first write fault, when page's anon_vma and index
1986 * are set. But now set the vm_pgoff it will almost certainly
1987 * end up with (unless mremap moves it elsewhere before that
1988 * first wfault), so /proc/pid/maps tells a consistent story.
1989 *
1990 * By setting it to reflect the virtual start address of the
1991 * vma, merges and splits can happen in a seamless way, just
1992 * using the existing file pgoff checks and manipulations.
1993 * Similarly in do_mmap_pgoff and in do_brk.
1994 */
1995 if (!vma->vm_file) {
1996 BUG_ON(vma->anon_vma);
1997 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
1998 }
1999 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2000 if (__vma && __vma->vm_start < vma->vm_end)
2001 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002002 if ((vma->vm_flags & VM_ACCOUNT) &&
2003 security_vm_enough_memory(vma_pages(vma)))
2004 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005 vma_link(mm, vma, prev, rb_link, rb_parent);
2006 return 0;
2007}
2008
2009/*
2010 * Copy the vma structure to a new location in the same mm,
2011 * prior to moving page table entries, to effect an mremap move.
2012 */
2013struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2014 unsigned long addr, unsigned long len, pgoff_t pgoff)
2015{
2016 struct vm_area_struct *vma = *vmap;
2017 unsigned long vma_start = vma->vm_start;
2018 struct mm_struct *mm = vma->vm_mm;
2019 struct vm_area_struct *new_vma, *prev;
2020 struct rb_node **rb_link, *rb_parent;
2021 struct mempolicy *pol;
2022
2023 /*
2024 * If anonymous vma has not yet been faulted, update new pgoff
2025 * to match new location, to increase its chance of merging.
2026 */
2027 if (!vma->vm_file && !vma->anon_vma)
2028 pgoff = addr >> PAGE_SHIFT;
2029
2030 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2031 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2032 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2033 if (new_vma) {
2034 /*
2035 * Source vma may have been merged into new_vma
2036 */
2037 if (vma_start >= new_vma->vm_start &&
2038 vma_start < new_vma->vm_end)
2039 *vmap = new_vma;
2040 } else {
2041 new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
2042 if (new_vma) {
2043 *new_vma = *vma;
2044 pol = mpol_copy(vma_policy(vma));
2045 if (IS_ERR(pol)) {
2046 kmem_cache_free(vm_area_cachep, new_vma);
2047 return NULL;
2048 }
2049 vma_set_policy(new_vma, pol);
2050 new_vma->vm_start = addr;
2051 new_vma->vm_end = addr + len;
2052 new_vma->vm_pgoff = pgoff;
2053 if (new_vma->vm_file)
2054 get_file(new_vma->vm_file);
2055 if (new_vma->vm_ops && new_vma->vm_ops->open)
2056 new_vma->vm_ops->open(new_vma);
2057 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2058 }
2059 }
2060 return new_vma;
2061}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002062
2063/*
2064 * Return true if the calling process may expand its vm space by the passed
2065 * number of pages
2066 */
2067int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2068{
2069 unsigned long cur = mm->total_vm; /* pages */
2070 unsigned long lim;
2071
2072 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2073
2074 if (cur + npages > lim)
2075 return 0;
2076 return 1;
2077}