blob: 906ed402f7cabda336a73d6d0d297b862b0d2932 [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>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080016#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/init.h>
18#include <linux/file.h>
19#include <linux/fs.h>
20#include <linux/personality.h>
21#include <linux/security.h>
22#include <linux/hugetlb.h>
23#include <linux/profile.h>
24#include <linux/module.h>
25#include <linux/mount.h>
26#include <linux/mempolicy.h>
27#include <linux/rmap.h>
28
29#include <asm/uaccess.h>
30#include <asm/cacheflush.h>
31#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020032#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Kirill Korotaev3a459752006-09-07 14:17:04 +040034#ifndef arch_mmap_check
35#define arch_mmap_check(addr, len, flags) (0)
36#endif
37
Hugh Dickinse0da3822005-04-19 13:29:15 -070038static void unmap_region(struct mm_struct *mm,
39 struct vm_area_struct *vma, struct vm_area_struct *prev,
40 unsigned long start, unsigned long end);
41
Linus Torvalds1da177e2005-04-16 15:20:36 -070042/*
43 * WARNING: the debugging will use recursive algorithms so never enable this
44 * unless you know what you are doing.
45 */
46#undef DEBUG_MM_RB
47
48/* description of effects of mapping type and prot in current implementation.
49 * this is due to the limited x86 page protection hardware. The expected
50 * behavior is in parens:
51 *
52 * map_type prot
53 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
54 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
55 * w: (no) no w: (no) no w: (yes) yes w: (no) no
56 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
57 *
58 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
59 * w: (no) no w: (no) no w: (copy) copy w: (no) no
60 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
61 *
62 */
63pgprot_t protection_map[16] = {
64 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
65 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
66};
67
Hugh Dickins804af2c2006-07-26 21:39:49 +010068pgprot_t vm_get_page_prot(unsigned long vm_flags)
69{
70 return protection_map[vm_flags &
71 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
72}
73EXPORT_SYMBOL(vm_get_page_prot);
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
76int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070077int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078atomic_t vm_committed_space = ATOMIC_INIT(0);
79
80/*
81 * Check that a process has enough memory to allocate a new virtual
82 * mapping. 0 means there is enough memory for the allocation to
83 * succeed and -ENOMEM implies there is not.
84 *
85 * We currently support three overcommit policies, which are set via the
86 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
87 *
88 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
89 * Additional code 2002 Jul 20 by Robert Love.
90 *
91 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
92 *
93 * Note this is a helper function intended to be used by LSMs which
94 * wish to use this logic.
95 */
96int __vm_enough_memory(long pages, int cap_sys_admin)
97{
98 unsigned long free, allowed;
99
100 vm_acct_memory(pages);
101
102 /*
103 * Sometimes we want to use more memory than we have
104 */
105 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
106 return 0;
107
108 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
109 unsigned long n;
110
Christoph Lameter347ce432006-06-30 01:55:35 -0700111 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 free += nr_swap_pages;
113
114 /*
115 * Any slabs which are created with the
116 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
117 * which are reclaimable, under pressure. The dentry
118 * cache and most inode caches should fall into this
119 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700120 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122 /*
123 * Leave the last 3% for root
124 */
125 if (!cap_sys_admin)
126 free -= free / 32;
127
128 if (free > pages)
129 return 0;
130
131 /*
132 * nr_free_pages() is very expensive on large systems,
133 * only call if we're about to fail.
134 */
135 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700136
137 /*
138 * Leave reserved pages. The pages are not for anonymous pages.
139 */
140 if (n <= totalreserve_pages)
141 goto error;
142 else
143 n -= totalreserve_pages;
144
145 /*
146 * Leave the last 3% for root
147 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 if (!cap_sys_admin)
149 n -= n / 32;
150 free += n;
151
152 if (free > pages)
153 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700154
155 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 }
157
158 allowed = (totalram_pages - hugetlb_total_pages())
159 * sysctl_overcommit_ratio / 100;
160 /*
161 * Leave the last 3% for root
162 */
163 if (!cap_sys_admin)
164 allowed -= allowed / 32;
165 allowed += total_swap_pages;
166
167 /* Don't let a single process grow too big:
168 leave 3% of the size of this process for other processes */
169 allowed -= current->mm->total_vm / 32;
170
Simon Derr2f60f8d2005-08-04 19:52:03 -0700171 /*
172 * cast `allowed' as a signed long because vm_committed_space
173 * sometimes has a negative value
174 */
175 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700177error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 vm_unacct_memory(pages);
179
180 return -ENOMEM;
181}
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183EXPORT_SYMBOL(__vm_enough_memory);
184
185/*
186 * Requires inode->i_mapping->i_mmap_lock
187 */
188static void __remove_shared_vm_struct(struct vm_area_struct *vma,
189 struct file *file, struct address_space *mapping)
190{
191 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800192 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 if (vma->vm_flags & VM_SHARED)
194 mapping->i_mmap_writable--;
195
196 flush_dcache_mmap_lock(mapping);
197 if (unlikely(vma->vm_flags & VM_NONLINEAR))
198 list_del_init(&vma->shared.vm_set.list);
199 else
200 vma_prio_tree_remove(vma, &mapping->i_mmap);
201 flush_dcache_mmap_unlock(mapping);
202}
203
204/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700205 * Unlink a file-based vm structure from its prio_tree, to hide
206 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700208void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
210 struct file *file = vma->vm_file;
211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 if (file) {
213 struct address_space *mapping = file->f_mapping;
214 spin_lock(&mapping->i_mmap_lock);
215 __remove_shared_vm_struct(vma, file, mapping);
216 spin_unlock(&mapping->i_mmap_lock);
217 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700218}
219
220/*
221 * Close a vm structure and free it, returning the next.
222 */
223static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
224{
225 struct vm_area_struct *next = vma->vm_next;
226
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700227 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 if (vma->vm_ops && vma->vm_ops->close)
229 vma->vm_ops->close(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700230 if (vma->vm_file)
231 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 mpol_free(vma_policy(vma));
233 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700234 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237asmlinkage unsigned long sys_brk(unsigned long brk)
238{
239 unsigned long rlim, retval;
240 unsigned long newbrk, oldbrk;
241 struct mm_struct *mm = current->mm;
242
243 down_write(&mm->mmap_sem);
244
245 if (brk < mm->end_code)
246 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700247
248 /*
249 * Check against rlimit here. If this check is done later after the test
250 * of oldbrk with newbrk then it can escape the test and let the data
251 * segment grow beyond its set limit the in case where the limit is
252 * not page aligned -Ram Gupta
253 */
254 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
255 if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
256 goto out;
257
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 newbrk = PAGE_ALIGN(brk);
259 oldbrk = PAGE_ALIGN(mm->brk);
260 if (oldbrk == newbrk)
261 goto set_brk;
262
263 /* Always allow shrinking brk. */
264 if (brk <= mm->brk) {
265 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
266 goto set_brk;
267 goto out;
268 }
269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 /* Check against existing mmap mappings. */
271 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
272 goto out;
273
274 /* Ok, looks good - let it rip. */
275 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
276 goto out;
277set_brk:
278 mm->brk = brk;
279out:
280 retval = mm->brk;
281 up_write(&mm->mmap_sem);
282 return retval;
283}
284
285#ifdef DEBUG_MM_RB
286static int browse_rb(struct rb_root *root)
287{
288 int i = 0, j;
289 struct rb_node *nd, *pn = NULL;
290 unsigned long prev = 0, pend = 0;
291
292 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
293 struct vm_area_struct *vma;
294 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
295 if (vma->vm_start < prev)
296 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
297 if (vma->vm_start < pend)
298 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
299 if (vma->vm_start > vma->vm_end)
300 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
301 i++;
302 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800303 prev = vma->vm_start;
304 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 }
306 j = 0;
307 for (nd = pn; nd; nd = rb_prev(nd)) {
308 j++;
309 }
310 if (i != j)
311 printk("backwards %d, forwards %d\n", j, i), i = 0;
312 return i;
313}
314
315void validate_mm(struct mm_struct *mm)
316{
317 int bug = 0;
318 int i = 0;
319 struct vm_area_struct *tmp = mm->mmap;
320 while (tmp) {
321 tmp = tmp->vm_next;
322 i++;
323 }
324 if (i != mm->map_count)
325 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
326 i = browse_rb(&mm->mm_rb);
327 if (i != mm->map_count)
328 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200329 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330}
331#else
332#define validate_mm(mm) do { } while (0)
333#endif
334
335static struct vm_area_struct *
336find_vma_prepare(struct mm_struct *mm, unsigned long addr,
337 struct vm_area_struct **pprev, struct rb_node ***rb_link,
338 struct rb_node ** rb_parent)
339{
340 struct vm_area_struct * vma;
341 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
342
343 __rb_link = &mm->mm_rb.rb_node;
344 rb_prev = __rb_parent = NULL;
345 vma = NULL;
346
347 while (*__rb_link) {
348 struct vm_area_struct *vma_tmp;
349
350 __rb_parent = *__rb_link;
351 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
352
353 if (vma_tmp->vm_end > addr) {
354 vma = vma_tmp;
355 if (vma_tmp->vm_start <= addr)
356 return vma;
357 __rb_link = &__rb_parent->rb_left;
358 } else {
359 rb_prev = __rb_parent;
360 __rb_link = &__rb_parent->rb_right;
361 }
362 }
363
364 *pprev = NULL;
365 if (rb_prev)
366 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
367 *rb_link = __rb_link;
368 *rb_parent = __rb_parent;
369 return vma;
370}
371
372static inline void
373__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
374 struct vm_area_struct *prev, struct rb_node *rb_parent)
375{
376 if (prev) {
377 vma->vm_next = prev->vm_next;
378 prev->vm_next = vma;
379 } else {
380 mm->mmap = vma;
381 if (rb_parent)
382 vma->vm_next = rb_entry(rb_parent,
383 struct vm_area_struct, vm_rb);
384 else
385 vma->vm_next = NULL;
386 }
387}
388
389void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
390 struct rb_node **rb_link, struct rb_node *rb_parent)
391{
392 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
393 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
394}
395
396static inline void __vma_link_file(struct vm_area_struct *vma)
397{
398 struct file * file;
399
400 file = vma->vm_file;
401 if (file) {
402 struct address_space *mapping = file->f_mapping;
403
404 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800405 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 if (vma->vm_flags & VM_SHARED)
407 mapping->i_mmap_writable++;
408
409 flush_dcache_mmap_lock(mapping);
410 if (unlikely(vma->vm_flags & VM_NONLINEAR))
411 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
412 else
413 vma_prio_tree_insert(vma, &mapping->i_mmap);
414 flush_dcache_mmap_unlock(mapping);
415 }
416}
417
418static void
419__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
420 struct vm_area_struct *prev, struct rb_node **rb_link,
421 struct rb_node *rb_parent)
422{
423 __vma_link_list(mm, vma, prev, rb_parent);
424 __vma_link_rb(mm, vma, rb_link, rb_parent);
425 __anon_vma_link(vma);
426}
427
428static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
429 struct vm_area_struct *prev, struct rb_node **rb_link,
430 struct rb_node *rb_parent)
431{
432 struct address_space *mapping = NULL;
433
434 if (vma->vm_file)
435 mapping = vma->vm_file->f_mapping;
436
437 if (mapping) {
438 spin_lock(&mapping->i_mmap_lock);
439 vma->vm_truncate_count = mapping->truncate_count;
440 }
441 anon_vma_lock(vma);
442
443 __vma_link(mm, vma, prev, rb_link, rb_parent);
444 __vma_link_file(vma);
445
446 anon_vma_unlock(vma);
447 if (mapping)
448 spin_unlock(&mapping->i_mmap_lock);
449
450 mm->map_count++;
451 validate_mm(mm);
452}
453
454/*
455 * Helper for vma_adjust in the split_vma insert case:
456 * insert vm structure into list and rbtree and anon_vma,
457 * but it has already been inserted into prio_tree earlier.
458 */
459static void
460__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
461{
462 struct vm_area_struct * __vma, * prev;
463 struct rb_node ** rb_link, * rb_parent;
464
465 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200466 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 __vma_link(mm, vma, prev, rb_link, rb_parent);
468 mm->map_count++;
469}
470
471static inline void
472__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
473 struct vm_area_struct *prev)
474{
475 prev->vm_next = vma->vm_next;
476 rb_erase(&vma->vm_rb, &mm->mm_rb);
477 if (mm->mmap_cache == vma)
478 mm->mmap_cache = prev;
479}
480
481/*
482 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
483 * is already present in an i_mmap tree without adjusting the tree.
484 * The following helper function should be used when such adjustments
485 * are necessary. The "insert" vma (if any) is to be inserted
486 * before we drop the necessary locks.
487 */
488void vma_adjust(struct vm_area_struct *vma, unsigned long start,
489 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
490{
491 struct mm_struct *mm = vma->vm_mm;
492 struct vm_area_struct *next = vma->vm_next;
493 struct vm_area_struct *importer = NULL;
494 struct address_space *mapping = NULL;
495 struct prio_tree_root *root = NULL;
496 struct file *file = vma->vm_file;
497 struct anon_vma *anon_vma = NULL;
498 long adjust_next = 0;
499 int remove_next = 0;
500
501 if (next && !insert) {
502 if (end >= next->vm_end) {
503 /*
504 * vma expands, overlapping all the next, and
505 * perhaps the one after too (mprotect case 6).
506 */
507again: remove_next = 1 + (end > next->vm_end);
508 end = next->vm_end;
509 anon_vma = next->anon_vma;
510 importer = vma;
511 } else if (end > next->vm_start) {
512 /*
513 * vma expands, overlapping part of the next:
514 * mprotect case 5 shifting the boundary up.
515 */
516 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
517 anon_vma = next->anon_vma;
518 importer = vma;
519 } else if (end < vma->vm_end) {
520 /*
521 * vma shrinks, and !insert tells it's not
522 * split_vma inserting another: so it must be
523 * mprotect case 4 shifting the boundary down.
524 */
525 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
526 anon_vma = next->anon_vma;
527 importer = next;
528 }
529 }
530
531 if (file) {
532 mapping = file->f_mapping;
533 if (!(vma->vm_flags & VM_NONLINEAR))
534 root = &mapping->i_mmap;
535 spin_lock(&mapping->i_mmap_lock);
536 if (importer &&
537 vma->vm_truncate_count != next->vm_truncate_count) {
538 /*
539 * unmap_mapping_range might be in progress:
540 * ensure that the expanding vma is rescanned.
541 */
542 importer->vm_truncate_count = 0;
543 }
544 if (insert) {
545 insert->vm_truncate_count = vma->vm_truncate_count;
546 /*
547 * Put into prio_tree now, so instantiated pages
548 * are visible to arm/parisc __flush_dcache_page
549 * throughout; but we cannot insert into address
550 * space until vma start or end is updated.
551 */
552 __vma_link_file(insert);
553 }
554 }
555
556 /*
557 * When changing only vma->vm_end, we don't really need
558 * anon_vma lock: but is that case worth optimizing out?
559 */
560 if (vma->anon_vma)
561 anon_vma = vma->anon_vma;
562 if (anon_vma) {
563 spin_lock(&anon_vma->lock);
564 /*
565 * Easily overlooked: when mprotect shifts the boundary,
566 * make sure the expanding vma has anon_vma set if the
567 * shrinking vma had, to cover any anon pages imported.
568 */
569 if (importer && !importer->anon_vma) {
570 importer->anon_vma = anon_vma;
571 __anon_vma_link(importer);
572 }
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 if (next->anon_vma)
606 __anon_vma_merge(vma, next);
607 } else if (insert) {
608 /*
609 * split_vma has split insert from vma, and needs
610 * us to insert it before dropping the locks
611 * (it may either follow vma or precede it).
612 */
613 __insert_vm_struct(mm, insert);
614 }
615
616 if (anon_vma)
617 spin_unlock(&anon_vma->lock);
618 if (mapping)
619 spin_unlock(&mapping->i_mmap_lock);
620
621 if (remove_next) {
622 if (file)
623 fput(file);
624 mm->map_count--;
625 mpol_free(vma_policy(next));
626 kmem_cache_free(vm_area_cachep, next);
627 /*
628 * In mprotect's case 6 (see comments on vma_merge),
629 * we must remove another next too. It would clutter
630 * up the code too much to do both in one go.
631 */
632 if (remove_next == 2) {
633 next = vma->vm_next;
634 goto again;
635 }
636 }
637
638 validate_mm(mm);
639}
640
641/*
642 * If the vma has a ->close operation then the driver probably needs to release
643 * per-vma resources, so we don't attempt to merge those.
644 */
Hugh Dickinsa6f563d2006-03-22 00:08:29 -0800645#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646
647static inline int is_mergeable_vma(struct vm_area_struct *vma,
648 struct file *file, unsigned long vm_flags)
649{
650 if (vma->vm_flags != vm_flags)
651 return 0;
652 if (vma->vm_file != file)
653 return 0;
654 if (vma->vm_ops && vma->vm_ops->close)
655 return 0;
656 return 1;
657}
658
659static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
660 struct anon_vma *anon_vma2)
661{
662 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
663}
664
665/*
666 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
667 * in front of (at a lower virtual address and file offset than) the vma.
668 *
669 * We cannot merge two vmas if they have differently assigned (non-NULL)
670 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
671 *
672 * We don't check here for the merged mmap wrapping around the end of pagecache
673 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
674 * wrap, nor mmaps which cover the final page at index -1UL.
675 */
676static int
677can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
678 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
679{
680 if (is_mergeable_vma(vma, file, vm_flags) &&
681 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
682 if (vma->vm_pgoff == vm_pgoff)
683 return 1;
684 }
685 return 0;
686}
687
688/*
689 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
690 * beyond (at a higher virtual address and file offset than) the vma.
691 *
692 * We cannot merge two vmas if they have differently assigned (non-NULL)
693 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
694 */
695static int
696can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
697 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
698{
699 if (is_mergeable_vma(vma, file, vm_flags) &&
700 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
701 pgoff_t vm_pglen;
702 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
703 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
704 return 1;
705 }
706 return 0;
707}
708
709/*
710 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
711 * whether that can be merged with its predecessor or its successor.
712 * Or both (it neatly fills a hole).
713 *
714 * In most cases - when called for mmap, brk or mremap - [addr,end) is
715 * certain not to be mapped by the time vma_merge is called; but when
716 * called for mprotect, it is certain to be already mapped (either at
717 * an offset within prev, or at the start of next), and the flags of
718 * this area are about to be changed to vm_flags - and the no-change
719 * case has already been eliminated.
720 *
721 * The following mprotect cases have to be considered, where AAAA is
722 * the area passed down from mprotect_fixup, never extending beyond one
723 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
724 *
725 * AAAA AAAA AAAA AAAA
726 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
727 * cannot merge might become might become might become
728 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
729 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
730 * mremap move: PPPPNNNNNNNN 8
731 * AAAA
732 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
733 * might become case 1 below case 2 below case 3 below
734 *
735 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
736 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
737 */
738struct vm_area_struct *vma_merge(struct mm_struct *mm,
739 struct vm_area_struct *prev, unsigned long addr,
740 unsigned long end, unsigned long vm_flags,
741 struct anon_vma *anon_vma, struct file *file,
742 pgoff_t pgoff, struct mempolicy *policy)
743{
744 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
745 struct vm_area_struct *area, *next;
746
747 /*
748 * We later require that vma->vm_flags == vm_flags,
749 * so this tests vma->vm_flags & VM_SPECIAL, too.
750 */
751 if (vm_flags & VM_SPECIAL)
752 return NULL;
753
754 if (prev)
755 next = prev->vm_next;
756 else
757 next = mm->mmap;
758 area = next;
759 if (next && next->vm_end == end) /* cases 6, 7, 8 */
760 next = next->vm_next;
761
762 /*
763 * Can it merge with the predecessor?
764 */
765 if (prev && prev->vm_end == addr &&
766 mpol_equal(vma_policy(prev), policy) &&
767 can_vma_merge_after(prev, vm_flags,
768 anon_vma, file, pgoff)) {
769 /*
770 * OK, it can. Can we now merge in the successor as well?
771 */
772 if (next && end == next->vm_start &&
773 mpol_equal(policy, vma_policy(next)) &&
774 can_vma_merge_before(next, vm_flags,
775 anon_vma, file, pgoff+pglen) &&
776 is_mergeable_anon_vma(prev->anon_vma,
777 next->anon_vma)) {
778 /* cases 1, 6 */
779 vma_adjust(prev, prev->vm_start,
780 next->vm_end, prev->vm_pgoff, NULL);
781 } else /* cases 2, 5, 7 */
782 vma_adjust(prev, prev->vm_start,
783 end, prev->vm_pgoff, NULL);
784 return prev;
785 }
786
787 /*
788 * Can this new request be merged in front of next?
789 */
790 if (next && end == next->vm_start &&
791 mpol_equal(policy, vma_policy(next)) &&
792 can_vma_merge_before(next, vm_flags,
793 anon_vma, file, pgoff+pglen)) {
794 if (prev && addr < prev->vm_end) /* case 4 */
795 vma_adjust(prev, prev->vm_start,
796 addr, prev->vm_pgoff, NULL);
797 else /* cases 3, 8 */
798 vma_adjust(area, addr, next->vm_end,
799 next->vm_pgoff - pglen, NULL);
800 return area;
801 }
802
803 return NULL;
804}
805
806/*
807 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
808 * neighbouring vmas for a suitable anon_vma, before it goes off
809 * to allocate a new anon_vma. It checks because a repetitive
810 * sequence of mprotects and faults may otherwise lead to distinct
811 * anon_vmas being allocated, preventing vma merge in subsequent
812 * mprotect.
813 */
814struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
815{
816 struct vm_area_struct *near;
817 unsigned long vm_flags;
818
819 near = vma->vm_next;
820 if (!near)
821 goto try_prev;
822
823 /*
824 * Since only mprotect tries to remerge vmas, match flags
825 * which might be mprotected into each other later on.
826 * Neither mlock nor madvise tries to remerge at present,
827 * so leave their flags as obstructing a merge.
828 */
829 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
830 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
831
832 if (near->anon_vma && vma->vm_end == near->vm_start &&
833 mpol_equal(vma_policy(vma), vma_policy(near)) &&
834 can_vma_merge_before(near, vm_flags,
835 NULL, vma->vm_file, vma->vm_pgoff +
836 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
837 return near->anon_vma;
838try_prev:
839 /*
840 * It is potentially slow to have to call find_vma_prev here.
841 * But it's only on the first write fault on the vma, not
842 * every time, and we could devise a way to avoid it later
843 * (e.g. stash info in next's anon_vma_node when assigning
844 * an anon_vma, or when trying vma_merge). Another time.
845 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200846 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 if (!near)
848 goto none;
849
850 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
851 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
852
853 if (near->anon_vma && near->vm_end == vma->vm_start &&
854 mpol_equal(vma_policy(near), vma_policy(vma)) &&
855 can_vma_merge_after(near, vm_flags,
856 NULL, vma->vm_file, vma->vm_pgoff))
857 return near->anon_vma;
858none:
859 /*
860 * There's no absolute need to look only at touching neighbours:
861 * we could search further afield for "compatible" anon_vmas.
862 * But it would probably just be a waste of time searching,
863 * or lead to too many vmas hanging off the same anon_vma.
864 * We're trying to allow mprotect remerging later on,
865 * not trying to minimize memory used for anon_vmas.
866 */
867 return NULL;
868}
869
870#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700871void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 struct file *file, long pages)
873{
874 const unsigned long stack_flags
875 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
876
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 if (file) {
878 mm->shared_vm += pages;
879 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
880 mm->exec_vm += pages;
881 } else if (flags & stack_flags)
882 mm->stack_vm += pages;
883 if (flags & (VM_RESERVED|VM_IO))
884 mm->reserved_vm += pages;
885}
886#endif /* CONFIG_PROC_FS */
887
888/*
889 * The caller must hold down_write(current->mm->mmap_sem).
890 */
891
892unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
893 unsigned long len, unsigned long prot,
894 unsigned long flags, unsigned long pgoff)
895{
896 struct mm_struct * mm = current->mm;
897 struct vm_area_struct * vma, * prev;
898 struct inode *inode;
899 unsigned int vm_flags;
900 int correct_wcount = 0;
901 int error;
902 struct rb_node ** rb_link, * rb_parent;
903 int accountable = 1;
904 unsigned long charged = 0, reqprot = prot;
905
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 /*
907 * Does the application expect PROT_READ to imply PROT_EXEC?
908 *
909 * (the exception is when the underlying filesystem is noexec
910 * mounted, in which case we dont add PROT_EXEC.)
911 */
912 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800913 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 prot |= PROT_EXEC;
915
916 if (!len)
917 return -EINVAL;
918
Kirill Korotaev3a459752006-09-07 14:17:04 +0400919 error = arch_mmap_check(addr, len, flags);
920 if (error)
921 return error;
922
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 /* Careful about overflows.. */
924 len = PAGE_ALIGN(len);
925 if (!len || len > TASK_SIZE)
926 return -ENOMEM;
927
928 /* offset overflow? */
929 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
930 return -EOVERFLOW;
931
932 /* Too many mappings? */
933 if (mm->map_count > sysctl_max_map_count)
934 return -ENOMEM;
935
936 /* Obtain the address to map to. we verify (or select) it and ensure
937 * that it represents a valid section of the address space.
938 */
939 addr = get_unmapped_area(file, addr, len, pgoff, flags);
940 if (addr & ~PAGE_MASK)
941 return addr;
942
943 /* Do simple checking here so the lower-level routines won't have
944 * to. we assume access permissions have been handled by the open
945 * of the memory object, so we don't do any here.
946 */
947 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
948 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
949
950 if (flags & MAP_LOCKED) {
951 if (!can_do_mlock())
952 return -EPERM;
953 vm_flags |= VM_LOCKED;
954 }
955 /* mlock MCL_FUTURE? */
956 if (vm_flags & VM_LOCKED) {
957 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700958 locked = len >> PAGE_SHIFT;
959 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700961 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
963 return -EAGAIN;
964 }
965
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800966 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
968 if (file) {
969 switch (flags & MAP_TYPE) {
970 case MAP_SHARED:
971 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
972 return -EACCES;
973
974 /*
975 * Make sure we don't allow writing to an append-only
976 * file..
977 */
978 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
979 return -EACCES;
980
981 /*
982 * Make sure there are no mandatory locks on the file.
983 */
984 if (locks_verify_locked(inode))
985 return -EAGAIN;
986
987 vm_flags |= VM_SHARED | VM_MAYSHARE;
988 if (!(file->f_mode & FMODE_WRITE))
989 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
990
991 /* fall through */
992 case MAP_PRIVATE:
993 if (!(file->f_mode & FMODE_READ))
994 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800995 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -0700996 if (vm_flags & VM_EXEC)
997 return -EPERM;
998 vm_flags &= ~VM_MAYEXEC;
999 }
1000 if (is_file_hugepages(file))
1001 accountable = 0;
1002
1003 if (!file->f_op || !file->f_op->mmap)
1004 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 break;
1006
1007 default:
1008 return -EINVAL;
1009 }
1010 } else {
1011 switch (flags & MAP_TYPE) {
1012 case MAP_SHARED:
1013 vm_flags |= VM_SHARED | VM_MAYSHARE;
1014 break;
1015 case MAP_PRIVATE:
1016 /*
1017 * Set pgoff according to addr for anon_vma.
1018 */
1019 pgoff = addr >> PAGE_SHIFT;
1020 break;
1021 default:
1022 return -EINVAL;
1023 }
1024 }
1025
1026 error = security_file_mmap(file, reqprot, prot, flags);
1027 if (error)
1028 return error;
1029
1030 /* Clear old maps */
1031 error = -ENOMEM;
1032munmap_back:
1033 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1034 if (vma && vma->vm_start < addr + len) {
1035 if (do_munmap(mm, addr, len))
1036 return -ENOMEM;
1037 goto munmap_back;
1038 }
1039
1040 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001041 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 return -ENOMEM;
1043
1044 if (accountable && (!(flags & MAP_NORESERVE) ||
1045 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1046 if (vm_flags & VM_SHARED) {
1047 /* Check memory availability in shmem_file_setup? */
1048 vm_flags |= VM_ACCOUNT;
1049 } else if (vm_flags & VM_WRITE) {
1050 /*
1051 * Private writable mapping: check memory availability
1052 */
1053 charged = len >> PAGE_SHIFT;
1054 if (security_vm_enough_memory(charged))
1055 return -ENOMEM;
1056 vm_flags |= VM_ACCOUNT;
1057 }
1058 }
1059
1060 /*
1061 * Can we just expand an old private anonymous mapping?
1062 * The VM_SHARED test is necessary because shmem_zero_setup
1063 * will create the file object for a shared anonymous map below.
1064 */
1065 if (!file && !(vm_flags & VM_SHARED) &&
1066 vma_merge(mm, prev, addr, addr + len, vm_flags,
1067 NULL, NULL, pgoff, NULL))
1068 goto out;
1069
1070 /*
1071 * Determine the object being mapped and call the appropriate
1072 * specific mapper. the address has already been validated, but
1073 * not unmapped, but the maps are removed from the list.
1074 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001075 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076 if (!vma) {
1077 error = -ENOMEM;
1078 goto unacct_error;
1079 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
1081 vma->vm_mm = mm;
1082 vma->vm_start = addr;
1083 vma->vm_end = addr + len;
1084 vma->vm_flags = vm_flags;
David Howells9637a5e2006-06-23 02:03:43 -07001085 vma->vm_page_prot = protection_map[vm_flags &
1086 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 vma->vm_pgoff = pgoff;
1088
1089 if (file) {
1090 error = -EINVAL;
1091 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1092 goto free_vma;
1093 if (vm_flags & VM_DENYWRITE) {
1094 error = deny_write_access(file);
1095 if (error)
1096 goto free_vma;
1097 correct_wcount = 1;
1098 }
1099 vma->vm_file = file;
1100 get_file(file);
1101 error = file->f_op->mmap(file, vma);
1102 if (error)
1103 goto unmap_and_free_vma;
1104 } else if (vm_flags & VM_SHARED) {
1105 error = shmem_zero_setup(vma);
1106 if (error)
1107 goto free_vma;
1108 }
1109
1110 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1111 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1112 * that memory reservation must be checked; but that reservation
1113 * belongs to shared memory object, not to vma: so now clear it.
1114 */
1115 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1116 vma->vm_flags &= ~VM_ACCOUNT;
1117
1118 /* Can addr have changed??
1119 *
1120 * Answer: Yes, several device drivers can do it in their
1121 * f_op->mmap method. -DaveM
1122 */
1123 addr = vma->vm_start;
1124 pgoff = vma->vm_pgoff;
1125 vm_flags = vma->vm_flags;
1126
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001127 if (vma_wants_writenotify(vma))
1128 vma->vm_page_prot =
1129 protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)];
1130
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
1132 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
1133 file = vma->vm_file;
1134 vma_link(mm, vma, prev, rb_link, rb_parent);
1135 if (correct_wcount)
1136 atomic_inc(&inode->i_writecount);
1137 } else {
1138 if (file) {
1139 if (correct_wcount)
1140 atomic_inc(&inode->i_writecount);
1141 fput(file);
1142 }
1143 mpol_free(vma_policy(vma));
1144 kmem_cache_free(vm_area_cachep, vma);
1145 }
1146out:
1147 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001148 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 if (vm_flags & VM_LOCKED) {
1150 mm->locked_vm += len >> PAGE_SHIFT;
1151 make_pages_present(addr, addr + len);
1152 }
1153 if (flags & MAP_POPULATE) {
1154 up_write(&mm->mmap_sem);
1155 sys_remap_file_pages(addr, len, 0,
1156 pgoff, flags & MAP_NONBLOCK);
1157 down_write(&mm->mmap_sem);
1158 }
1159 return addr;
1160
1161unmap_and_free_vma:
1162 if (correct_wcount)
1163 atomic_inc(&inode->i_writecount);
1164 vma->vm_file = NULL;
1165 fput(file);
1166
1167 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001168 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1169 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170free_vma:
1171 kmem_cache_free(vm_area_cachep, vma);
1172unacct_error:
1173 if (charged)
1174 vm_unacct_memory(charged);
1175 return error;
1176}
1177
1178EXPORT_SYMBOL(do_mmap_pgoff);
1179
1180/* Get an address range which is currently unmapped.
1181 * For shmat() with addr=0.
1182 *
1183 * Ugly calling convention alert:
1184 * Return value with the low bits set means error value,
1185 * ie
1186 * if (ret & ~PAGE_MASK)
1187 * error = ret;
1188 *
1189 * This function "knows" that -ENOMEM has the bits set.
1190 */
1191#ifndef HAVE_ARCH_UNMAPPED_AREA
1192unsigned long
1193arch_get_unmapped_area(struct file *filp, unsigned long addr,
1194 unsigned long len, unsigned long pgoff, unsigned long flags)
1195{
1196 struct mm_struct *mm = current->mm;
1197 struct vm_area_struct *vma;
1198 unsigned long start_addr;
1199
1200 if (len > TASK_SIZE)
1201 return -ENOMEM;
1202
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001203 if (flags & MAP_FIXED)
1204 return addr;
1205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 if (addr) {
1207 addr = PAGE_ALIGN(addr);
1208 vma = find_vma(mm, addr);
1209 if (TASK_SIZE - len >= addr &&
1210 (!vma || addr + len <= vma->vm_start))
1211 return addr;
1212 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001213 if (len > mm->cached_hole_size) {
1214 start_addr = addr = mm->free_area_cache;
1215 } else {
1216 start_addr = addr = TASK_UNMAPPED_BASE;
1217 mm->cached_hole_size = 0;
1218 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219
1220full_search:
1221 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1222 /* At this point: (!vma || addr < vma->vm_end). */
1223 if (TASK_SIZE - len < addr) {
1224 /*
1225 * Start a new search - just in case we missed
1226 * some holes.
1227 */
1228 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001229 addr = TASK_UNMAPPED_BASE;
1230 start_addr = addr;
1231 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 goto full_search;
1233 }
1234 return -ENOMEM;
1235 }
1236 if (!vma || addr + len <= vma->vm_start) {
1237 /*
1238 * Remember the place where we stopped the search:
1239 */
1240 mm->free_area_cache = addr + len;
1241 return addr;
1242 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001243 if (addr + mm->cached_hole_size < vma->vm_start)
1244 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 addr = vma->vm_end;
1246 }
1247}
1248#endif
1249
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001250void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251{
1252 /*
1253 * Is this a new hole at the lowest possible address?
1254 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001255 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1256 mm->free_area_cache = addr;
1257 mm->cached_hole_size = ~0UL;
1258 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259}
1260
1261/*
1262 * This mmap-allocator allocates new areas top-down from below the
1263 * stack's low limit (the base):
1264 */
1265#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1266unsigned long
1267arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1268 const unsigned long len, const unsigned long pgoff,
1269 const unsigned long flags)
1270{
1271 struct vm_area_struct *vma;
1272 struct mm_struct *mm = current->mm;
1273 unsigned long addr = addr0;
1274
1275 /* requested length too big for entire address space */
1276 if (len > TASK_SIZE)
1277 return -ENOMEM;
1278
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001279 if (flags & MAP_FIXED)
1280 return addr;
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 /* requesting a specific address */
1283 if (addr) {
1284 addr = PAGE_ALIGN(addr);
1285 vma = find_vma(mm, addr);
1286 if (TASK_SIZE - len >= addr &&
1287 (!vma || addr + len <= vma->vm_start))
1288 return addr;
1289 }
1290
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001291 /* check if free_area_cache is useful for us */
1292 if (len <= mm->cached_hole_size) {
1293 mm->cached_hole_size = 0;
1294 mm->free_area_cache = mm->mmap_base;
1295 }
1296
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 /* either no address requested or can't fit in requested address hole */
1298 addr = mm->free_area_cache;
1299
1300 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001301 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 vma = find_vma(mm, addr-len);
1303 if (!vma || addr <= vma->vm_start)
1304 /* remember the address as a hint for next time */
1305 return (mm->free_area_cache = addr-len);
1306 }
1307
Chris Wright73219d12005-06-21 17:14:52 -07001308 if (mm->mmap_base < len)
1309 goto bottomup;
1310
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 addr = mm->mmap_base-len;
1312
1313 do {
1314 /*
1315 * Lookup failure means no vma is above this address,
1316 * else if new region fits below vma->vm_start,
1317 * return with success:
1318 */
1319 vma = find_vma(mm, addr);
1320 if (!vma || addr+len <= vma->vm_start)
1321 /* remember the address as a hint for next time */
1322 return (mm->free_area_cache = addr);
1323
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001324 /* remember the largest hole we saw so far */
1325 if (addr + mm->cached_hole_size < vma->vm_start)
1326 mm->cached_hole_size = vma->vm_start - addr;
1327
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 /* try just below the current vma->vm_start */
1329 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001330 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331
Chris Wright73219d12005-06-21 17:14:52 -07001332bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 /*
1334 * A failed mmap() very likely causes application failure,
1335 * so fall back to the bottom-up function here. This scenario
1336 * can happen with large stack limits and large mmap()
1337 * allocations.
1338 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001339 mm->cached_hole_size = ~0UL;
1340 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1342 /*
1343 * Restore the topdown base:
1344 */
1345 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001346 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347
1348 return addr;
1349}
1350#endif
1351
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001352void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353{
1354 /*
1355 * Is this a new hole at the highest possible address?
1356 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001357 if (addr > mm->free_area_cache)
1358 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359
1360 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001361 if (mm->free_area_cache > mm->mmap_base)
1362 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363}
1364
1365unsigned long
1366get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1367 unsigned long pgoff, unsigned long flags)
1368{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001369 unsigned long (*get_area)(struct file *, unsigned long,
1370 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001372 get_area = current->mm->get_unmapped_area;
1373 if (file && file->f_op && file->f_op->get_unmapped_area)
1374 get_area = file->f_op->get_unmapped_area;
1375 addr = get_area(file, addr, len, pgoff, flags);
1376 if (IS_ERR_VALUE(addr))
1377 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001379 if (addr > TASK_SIZE - len)
1380 return -ENOMEM;
1381 if (addr & ~PAGE_MASK)
1382 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001383
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001384 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385}
1386
1387EXPORT_SYMBOL(get_unmapped_area);
1388
1389/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1390struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1391{
1392 struct vm_area_struct *vma = NULL;
1393
1394 if (mm) {
1395 /* Check the cache first. */
1396 /* (Cache hit rate is typically around 35%.) */
1397 vma = mm->mmap_cache;
1398 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1399 struct rb_node * rb_node;
1400
1401 rb_node = mm->mm_rb.rb_node;
1402 vma = NULL;
1403
1404 while (rb_node) {
1405 struct vm_area_struct * vma_tmp;
1406
1407 vma_tmp = rb_entry(rb_node,
1408 struct vm_area_struct, vm_rb);
1409
1410 if (vma_tmp->vm_end > addr) {
1411 vma = vma_tmp;
1412 if (vma_tmp->vm_start <= addr)
1413 break;
1414 rb_node = rb_node->rb_left;
1415 } else
1416 rb_node = rb_node->rb_right;
1417 }
1418 if (vma)
1419 mm->mmap_cache = vma;
1420 }
1421 }
1422 return vma;
1423}
1424
1425EXPORT_SYMBOL(find_vma);
1426
1427/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1428struct vm_area_struct *
1429find_vma_prev(struct mm_struct *mm, unsigned long addr,
1430 struct vm_area_struct **pprev)
1431{
1432 struct vm_area_struct *vma = NULL, *prev = NULL;
1433 struct rb_node * rb_node;
1434 if (!mm)
1435 goto out;
1436
1437 /* Guard against addr being lower than the first VMA */
1438 vma = mm->mmap;
1439
1440 /* Go through the RB tree quickly. */
1441 rb_node = mm->mm_rb.rb_node;
1442
1443 while (rb_node) {
1444 struct vm_area_struct *vma_tmp;
1445 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1446
1447 if (addr < vma_tmp->vm_end) {
1448 rb_node = rb_node->rb_left;
1449 } else {
1450 prev = vma_tmp;
1451 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1452 break;
1453 rb_node = rb_node->rb_right;
1454 }
1455 }
1456
1457out:
1458 *pprev = prev;
1459 return prev ? prev->vm_next : vma;
1460}
1461
1462/*
1463 * Verify that the stack growth is acceptable and
1464 * update accounting. This is shared with both the
1465 * grow-up and grow-down cases.
1466 */
1467static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1468{
1469 struct mm_struct *mm = vma->vm_mm;
1470 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001471 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472
1473 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001474 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 return -ENOMEM;
1476
1477 /* Stack limit test */
1478 if (size > rlim[RLIMIT_STACK].rlim_cur)
1479 return -ENOMEM;
1480
1481 /* mlock limit tests */
1482 if (vma->vm_flags & VM_LOCKED) {
1483 unsigned long locked;
1484 unsigned long limit;
1485 locked = mm->locked_vm + grow;
1486 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1487 if (locked > limit && !capable(CAP_IPC_LOCK))
1488 return -ENOMEM;
1489 }
1490
Adam Litke0d59a012007-01-30 14:35:39 -08001491 /* Check to ensure the stack will not grow into a hugetlb-only region */
1492 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1493 vma->vm_end - size;
1494 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1495 return -EFAULT;
1496
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 /*
1498 * Overcommit.. This must be the final test, as it will
1499 * update security statistics.
1500 */
1501 if (security_vm_enough_memory(grow))
1502 return -ENOMEM;
1503
1504 /* Ok, everything looks good - let it rip */
1505 mm->total_vm += grow;
1506 if (vma->vm_flags & VM_LOCKED)
1507 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001508 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509 return 0;
1510}
1511
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001512#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001514 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1515 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001517#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001518static inline
1519#endif
1520int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521{
1522 int error;
1523
1524 if (!(vma->vm_flags & VM_GROWSUP))
1525 return -EFAULT;
1526
1527 /*
1528 * We must make sure the anon_vma is allocated
1529 * so that the anon_vma locking is not a noop.
1530 */
1531 if (unlikely(anon_vma_prepare(vma)))
1532 return -ENOMEM;
1533 anon_vma_lock(vma);
1534
1535 /*
1536 * vma->vm_start/vm_end cannot change under us because the caller
1537 * is required to hold the mmap_sem in read mode. We need the
1538 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001539 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 */
Helge Deller06b32f32006-12-19 19:28:33 +01001541 if (address < PAGE_ALIGN(address+4))
1542 address = PAGE_ALIGN(address+4);
1543 else {
1544 anon_vma_unlock(vma);
1545 return -ENOMEM;
1546 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547 error = 0;
1548
1549 /* Somebody else might have raced and expanded it already */
1550 if (address > vma->vm_end) {
1551 unsigned long size, grow;
1552
1553 size = address - vma->vm_start;
1554 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1555
1556 error = acct_stack_growth(vma, size, grow);
1557 if (!error)
1558 vma->vm_end = address;
1559 }
1560 anon_vma_unlock(vma);
1561 return error;
1562}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001563#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1564
1565#ifdef CONFIG_STACK_GROWSUP
1566int expand_stack(struct vm_area_struct *vma, unsigned long address)
1567{
1568 return expand_upwards(vma, address);
1569}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570
1571struct vm_area_struct *
1572find_extend_vma(struct mm_struct *mm, unsigned long addr)
1573{
1574 struct vm_area_struct *vma, *prev;
1575
1576 addr &= PAGE_MASK;
1577 vma = find_vma_prev(mm, addr, &prev);
1578 if (vma && (vma->vm_start <= addr))
1579 return vma;
1580 if (!prev || expand_stack(prev, addr))
1581 return NULL;
1582 if (prev->vm_flags & VM_LOCKED) {
1583 make_pages_present(addr, prev->vm_end);
1584 }
1585 return prev;
1586}
1587#else
1588/*
1589 * vma is the first one with address < vma->vm_start. Have to extend vma.
1590 */
1591int expand_stack(struct vm_area_struct *vma, unsigned long address)
1592{
1593 int error;
1594
1595 /*
1596 * We must make sure the anon_vma is allocated
1597 * so that the anon_vma locking is not a noop.
1598 */
1599 if (unlikely(anon_vma_prepare(vma)))
1600 return -ENOMEM;
1601 anon_vma_lock(vma);
1602
1603 /*
1604 * vma->vm_start/vm_end cannot change under us because the caller
1605 * is required to hold the mmap_sem in read mode. We need the
1606 * anon_vma lock to serialize against concurrent expand_stacks.
1607 */
1608 address &= PAGE_MASK;
1609 error = 0;
1610
1611 /* Somebody else might have raced and expanded it already */
1612 if (address < vma->vm_start) {
1613 unsigned long size, grow;
1614
1615 size = vma->vm_end - address;
1616 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1617
1618 error = acct_stack_growth(vma, size, grow);
1619 if (!error) {
1620 vma->vm_start = address;
1621 vma->vm_pgoff -= grow;
1622 }
1623 }
1624 anon_vma_unlock(vma);
1625 return error;
1626}
1627
1628struct vm_area_struct *
1629find_extend_vma(struct mm_struct * mm, unsigned long addr)
1630{
1631 struct vm_area_struct * vma;
1632 unsigned long start;
1633
1634 addr &= PAGE_MASK;
1635 vma = find_vma(mm,addr);
1636 if (!vma)
1637 return NULL;
1638 if (vma->vm_start <= addr)
1639 return vma;
1640 if (!(vma->vm_flags & VM_GROWSDOWN))
1641 return NULL;
1642 start = vma->vm_start;
1643 if (expand_stack(vma, addr))
1644 return NULL;
1645 if (vma->vm_flags & VM_LOCKED) {
1646 make_pages_present(addr, start);
1647 }
1648 return vma;
1649}
1650#endif
1651
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001653 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001655 *
1656 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001658static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001660 /* Update high watermark before we lower total_vm */
1661 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001663 long nrpages = vma_pages(vma);
1664
1665 mm->total_vm -= nrpages;
1666 if (vma->vm_flags & VM_LOCKED)
1667 mm->locked_vm -= nrpages;
1668 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001669 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001670 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671 validate_mm(mm);
1672}
1673
1674/*
1675 * Get rid of page table information in the indicated region.
1676 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001677 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001678 */
1679static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001680 struct vm_area_struct *vma, struct vm_area_struct *prev,
1681 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001683 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 struct mmu_gather *tlb;
1685 unsigned long nr_accounted = 0;
1686
1687 lru_add_drain();
1688 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001689 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001690 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001692 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001693 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 tlb_finish_mmu(tlb, start, end);
1695}
1696
1697/*
1698 * Create a list of vma's touched by the unmap, removing them from the mm's
1699 * vma list as we go..
1700 */
1701static void
1702detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1703 struct vm_area_struct *prev, unsigned long end)
1704{
1705 struct vm_area_struct **insertion_point;
1706 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001707 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708
1709 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1710 do {
1711 rb_erase(&vma->vm_rb, &mm->mm_rb);
1712 mm->map_count--;
1713 tail_vma = vma;
1714 vma = vma->vm_next;
1715 } while (vma && vma->vm_start < end);
1716 *insertion_point = vma;
1717 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001718 if (mm->unmap_area == arch_unmap_area)
1719 addr = prev ? prev->vm_end : mm->mmap_base;
1720 else
1721 addr = vma ? vma->vm_start : mm->mmap_base;
1722 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723 mm->mmap_cache = NULL; /* Kill the cache. */
1724}
1725
1726/*
1727 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001728 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 */
1730int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1731 unsigned long addr, int new_below)
1732{
1733 struct mempolicy *pol;
1734 struct vm_area_struct *new;
1735
1736 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1737 return -EINVAL;
1738
1739 if (mm->map_count >= sysctl_max_map_count)
1740 return -ENOMEM;
1741
Christoph Lametere94b1762006-12-06 20:33:17 -08001742 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 if (!new)
1744 return -ENOMEM;
1745
1746 /* most fields are the same, copy all, and then fixup */
1747 *new = *vma;
1748
1749 if (new_below)
1750 new->vm_end = addr;
1751 else {
1752 new->vm_start = addr;
1753 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1754 }
1755
1756 pol = mpol_copy(vma_policy(vma));
1757 if (IS_ERR(pol)) {
1758 kmem_cache_free(vm_area_cachep, new);
1759 return PTR_ERR(pol);
1760 }
1761 vma_set_policy(new, pol);
1762
1763 if (new->vm_file)
1764 get_file(new->vm_file);
1765
1766 if (new->vm_ops && new->vm_ops->open)
1767 new->vm_ops->open(new);
1768
1769 if (new_below)
1770 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1771 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1772 else
1773 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1774
1775 return 0;
1776}
1777
1778/* Munmap is split into 2 main parts -- this part which finds
1779 * what needs doing, and the areas themselves, which do the
1780 * work. This now handles partial unmappings.
1781 * Jeremy Fitzhardinge <jeremy@goop.org>
1782 */
1783int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1784{
1785 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001786 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
1788 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1789 return -EINVAL;
1790
1791 if ((len = PAGE_ALIGN(len)) == 0)
1792 return -EINVAL;
1793
1794 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001795 vma = find_vma_prev(mm, start, &prev);
1796 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001798 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799
1800 /* if it doesn't overlap, we have nothing.. */
1801 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001802 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 return 0;
1804
1805 /*
1806 * If we need to split any vma, do it now to save pain later.
1807 *
1808 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1809 * unmapped vm_area_struct will remain in use: so lower split_vma
1810 * places tmp vma above, and higher split_vma places tmp vma below.
1811 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001812 if (start > vma->vm_start) {
1813 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 if (error)
1815 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001816 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 }
1818
1819 /* Does it split the last one? */
1820 last = find_vma(mm, end);
1821 if (last && end > last->vm_start) {
1822 int error = split_vma(mm, last, end, 1);
1823 if (error)
1824 return error;
1825 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001826 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827
1828 /*
1829 * Remove the vma's, and unmap the actual pages
1830 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001831 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1832 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833
1834 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001835 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836
1837 return 0;
1838}
1839
1840EXPORT_SYMBOL(do_munmap);
1841
1842asmlinkage long sys_munmap(unsigned long addr, size_t len)
1843{
1844 int ret;
1845 struct mm_struct *mm = current->mm;
1846
1847 profile_munmap(addr);
1848
1849 down_write(&mm->mmap_sem);
1850 ret = do_munmap(mm, addr, len);
1851 up_write(&mm->mmap_sem);
1852 return ret;
1853}
1854
1855static inline void verify_mm_writelocked(struct mm_struct *mm)
1856{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001857#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1859 WARN_ON(1);
1860 up_read(&mm->mmap_sem);
1861 }
1862#endif
1863}
1864
1865/*
1866 * this is really a simplified "do_mmap". it only handles
1867 * anonymous maps. eventually we may be able to do some
1868 * brk-specific accounting here.
1869 */
1870unsigned long do_brk(unsigned long addr, unsigned long len)
1871{
1872 struct mm_struct * mm = current->mm;
1873 struct vm_area_struct * vma, * prev;
1874 unsigned long flags;
1875 struct rb_node ** rb_link, * rb_parent;
1876 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001877 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878
1879 len = PAGE_ALIGN(len);
1880 if (!len)
1881 return addr;
1882
1883 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1884 return -EINVAL;
1885
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001886 if (is_hugepage_only_range(mm, addr, len))
1887 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001888
Kirill Korotaev3a459752006-09-07 14:17:04 +04001889 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1890
1891 error = arch_mmap_check(addr, len, flags);
1892 if (error)
1893 return error;
1894
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 /*
1896 * mlock MCL_FUTURE?
1897 */
1898 if (mm->def_flags & VM_LOCKED) {
1899 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001900 locked = len >> PAGE_SHIFT;
1901 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001903 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1905 return -EAGAIN;
1906 }
1907
1908 /*
1909 * mm->mmap_sem is required to protect against another thread
1910 * changing the mappings in case we sleep.
1911 */
1912 verify_mm_writelocked(mm);
1913
1914 /*
1915 * Clear old maps. this also does some error checking for us
1916 */
1917 munmap_back:
1918 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1919 if (vma && vma->vm_start < addr + len) {
1920 if (do_munmap(mm, addr, len))
1921 return -ENOMEM;
1922 goto munmap_back;
1923 }
1924
1925 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001926 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927 return -ENOMEM;
1928
1929 if (mm->map_count > sysctl_max_map_count)
1930 return -ENOMEM;
1931
1932 if (security_vm_enough_memory(len >> PAGE_SHIFT))
1933 return -ENOMEM;
1934
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935 /* Can we just expand an old private anonymous mapping? */
1936 if (vma_merge(mm, prev, addr, addr + len, flags,
1937 NULL, NULL, pgoff, NULL))
1938 goto out;
1939
1940 /*
1941 * create a vma struct for an anonymous mapping
1942 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001943 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944 if (!vma) {
1945 vm_unacct_memory(len >> PAGE_SHIFT);
1946 return -ENOMEM;
1947 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948
1949 vma->vm_mm = mm;
1950 vma->vm_start = addr;
1951 vma->vm_end = addr + len;
1952 vma->vm_pgoff = pgoff;
1953 vma->vm_flags = flags;
David Howells9637a5e2006-06-23 02:03:43 -07001954 vma->vm_page_prot = protection_map[flags &
1955 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 vma_link(mm, vma, prev, rb_link, rb_parent);
1957out:
1958 mm->total_vm += len >> PAGE_SHIFT;
1959 if (flags & VM_LOCKED) {
1960 mm->locked_vm += len >> PAGE_SHIFT;
1961 make_pages_present(addr, addr + len);
1962 }
1963 return addr;
1964}
1965
1966EXPORT_SYMBOL(do_brk);
1967
1968/* Release all mmaps. */
1969void exit_mmap(struct mm_struct *mm)
1970{
1971 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07001972 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07001974 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02001976 /* mm's last user has gone, and its about to be pulled down */
1977 arch_exit_mmap(mm);
1978
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07001981 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001982 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001983 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07001984 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001986 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001987 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07001990 * Walk the list again, actually closing and freeing it,
1991 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001993 while (vma)
1994 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07001995
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001996 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997}
1998
1999/* Insert vm structure into process list sorted by address
2000 * and into the inode's i_mmap tree. If vm_file is non-NULL
2001 * then i_mmap_lock is taken here.
2002 */
2003int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2004{
2005 struct vm_area_struct * __vma, * prev;
2006 struct rb_node ** rb_link, * rb_parent;
2007
2008 /*
2009 * The vm_pgoff of a purely anonymous vma should be irrelevant
2010 * until its first write fault, when page's anon_vma and index
2011 * are set. But now set the vm_pgoff it will almost certainly
2012 * end up with (unless mremap moves it elsewhere before that
2013 * first wfault), so /proc/pid/maps tells a consistent story.
2014 *
2015 * By setting it to reflect the virtual start address of the
2016 * vma, merges and splits can happen in a seamless way, just
2017 * using the existing file pgoff checks and manipulations.
2018 * Similarly in do_mmap_pgoff and in do_brk.
2019 */
2020 if (!vma->vm_file) {
2021 BUG_ON(vma->anon_vma);
2022 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2023 }
2024 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2025 if (__vma && __vma->vm_start < vma->vm_end)
2026 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002027 if ((vma->vm_flags & VM_ACCOUNT) &&
2028 security_vm_enough_memory(vma_pages(vma)))
2029 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030 vma_link(mm, vma, prev, rb_link, rb_parent);
2031 return 0;
2032}
2033
2034/*
2035 * Copy the vma structure to a new location in the same mm,
2036 * prior to moving page table entries, to effect an mremap move.
2037 */
2038struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2039 unsigned long addr, unsigned long len, pgoff_t pgoff)
2040{
2041 struct vm_area_struct *vma = *vmap;
2042 unsigned long vma_start = vma->vm_start;
2043 struct mm_struct *mm = vma->vm_mm;
2044 struct vm_area_struct *new_vma, *prev;
2045 struct rb_node **rb_link, *rb_parent;
2046 struct mempolicy *pol;
2047
2048 /*
2049 * If anonymous vma has not yet been faulted, update new pgoff
2050 * to match new location, to increase its chance of merging.
2051 */
2052 if (!vma->vm_file && !vma->anon_vma)
2053 pgoff = addr >> PAGE_SHIFT;
2054
2055 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2056 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2057 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2058 if (new_vma) {
2059 /*
2060 * Source vma may have been merged into new_vma
2061 */
2062 if (vma_start >= new_vma->vm_start &&
2063 vma_start < new_vma->vm_end)
2064 *vmap = new_vma;
2065 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002066 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067 if (new_vma) {
2068 *new_vma = *vma;
2069 pol = mpol_copy(vma_policy(vma));
2070 if (IS_ERR(pol)) {
2071 kmem_cache_free(vm_area_cachep, new_vma);
2072 return NULL;
2073 }
2074 vma_set_policy(new_vma, pol);
2075 new_vma->vm_start = addr;
2076 new_vma->vm_end = addr + len;
2077 new_vma->vm_pgoff = pgoff;
2078 if (new_vma->vm_file)
2079 get_file(new_vma->vm_file);
2080 if (new_vma->vm_ops && new_vma->vm_ops->open)
2081 new_vma->vm_ops->open(new_vma);
2082 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2083 }
2084 }
2085 return new_vma;
2086}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002087
2088/*
2089 * Return true if the calling process may expand its vm space by the passed
2090 * number of pages
2091 */
2092int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2093{
2094 unsigned long cur = mm->total_vm; /* pages */
2095 unsigned long lim;
2096
2097 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2098
2099 if (cur + npages > lim)
2100 return 0;
2101 return 1;
2102}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002103
2104
2105static struct page *special_mapping_nopage(struct vm_area_struct *vma,
2106 unsigned long address, int *type)
2107{
2108 struct page **pages;
2109
2110 BUG_ON(address < vma->vm_start || address >= vma->vm_end);
2111
2112 address -= vma->vm_start;
2113 for (pages = vma->vm_private_data; address > 0 && *pages; ++pages)
2114 address -= PAGE_SIZE;
2115
2116 if (*pages) {
2117 struct page *page = *pages;
2118 get_page(page);
2119 return page;
2120 }
2121
2122 return NOPAGE_SIGBUS;
2123}
2124
2125/*
2126 * Having a close hook prevents vma merging regardless of flags.
2127 */
2128static void special_mapping_close(struct vm_area_struct *vma)
2129{
2130}
2131
2132static struct vm_operations_struct special_mapping_vmops = {
2133 .close = special_mapping_close,
2134 .nopage = special_mapping_nopage,
2135};
2136
2137/*
2138 * Called with mm->mmap_sem held for writing.
2139 * Insert a new vma covering the given region, with the given flags.
2140 * Its pages are supplied by the given array of struct page *.
2141 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2142 * The region past the last page supplied will always produce SIGBUS.
2143 * The array pointer and the pages it points to are assumed to stay alive
2144 * for as long as this mapping might exist.
2145 */
2146int install_special_mapping(struct mm_struct *mm,
2147 unsigned long addr, unsigned long len,
2148 unsigned long vm_flags, struct page **pages)
2149{
2150 struct vm_area_struct *vma;
2151
2152 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2153 if (unlikely(vma == NULL))
2154 return -ENOMEM;
2155
2156 vma->vm_mm = mm;
2157 vma->vm_start = addr;
2158 vma->vm_end = addr + len;
2159
2160 vma->vm_flags = vm_flags | mm->def_flags;
2161 vma->vm_page_prot = protection_map[vma->vm_flags & 7];
2162
2163 vma->vm_ops = &special_mapping_vmops;
2164 vma->vm_private_data = pages;
2165
2166 if (unlikely(insert_vm_struct(mm, vma))) {
2167 kmem_cache_free(vm_area_cachep, vma);
2168 return -ENOMEM;
2169 }
2170
2171 mm->total_vm += len >> PAGE_SHIFT;
2172
2173 return 0;
2174}