blob: 245c3d69067b7bc4c0b83ba2fa6a08df28bc7f9b [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>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070010#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070029#include <linux/mmu_notifier.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include <asm/uaccess.h>
32#include <asm/cacheflush.h>
33#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020034#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Jan Beulich42b77722008-07-23 21:27:10 -070036#include "internal.h"
37
Kirill Korotaev3a459752006-09-07 14:17:04 +040038#ifndef arch_mmap_check
39#define arch_mmap_check(addr, len, flags) (0)
40#endif
41
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080042#ifndef arch_rebalance_pgtables
43#define arch_rebalance_pgtables(addr, len) (addr)
44#endif
45
Hugh Dickinse0da3822005-04-19 13:29:15 -070046static void unmap_region(struct mm_struct *mm,
47 struct vm_area_struct *vma, struct vm_area_struct *prev,
48 unsigned long start, unsigned long end);
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*
51 * WARNING: the debugging will use recursive algorithms so never enable this
52 * unless you know what you are doing.
53 */
54#undef DEBUG_MM_RB
55
56/* description of effects of mapping type and prot in current implementation.
57 * this is due to the limited x86 page protection hardware. The expected
58 * behavior is in parens:
59 *
60 * map_type prot
61 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
62 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
63 * w: (no) no w: (no) no w: (yes) yes w: (no) no
64 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
65 *
66 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
67 * w: (no) no w: (no) no w: (copy) copy w: (no) no
68 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
69 *
70 */
71pgprot_t protection_map[16] = {
72 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
73 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
74};
75
Hugh Dickins804af2c2006-07-26 21:39:49 +010076pgprot_t vm_get_page_prot(unsigned long vm_flags)
77{
Dave Kleikampb845f312008-07-08 00:28:51 +100078 return __pgprot(pgprot_val(protection_map[vm_flags &
79 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
80 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010081}
82EXPORT_SYMBOL(vm_get_page_prot);
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
85int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070086int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Alan Cox80119ef2008-05-23 13:04:31 -070087atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89/*
90 * Check that a process has enough memory to allocate a new virtual
91 * mapping. 0 means there is enough memory for the allocation to
92 * succeed and -ENOMEM implies there is not.
93 *
94 * We currently support three overcommit policies, which are set via the
95 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
96 *
97 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
98 * Additional code 2002 Jul 20 by Robert Love.
99 *
100 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
101 *
102 * Note this is a helper function intended to be used by LSMs which
103 * wish to use this logic.
104 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700105int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106{
107 unsigned long free, allowed;
108
109 vm_acct_memory(pages);
110
111 /*
112 * Sometimes we want to use more memory than we have
113 */
114 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
115 return 0;
116
117 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
118 unsigned long n;
119
Christoph Lameter347ce432006-06-30 01:55:35 -0700120 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 free += nr_swap_pages;
122
123 /*
124 * Any slabs which are created with the
125 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
126 * which are reclaimable, under pressure. The dentry
127 * cache and most inode caches should fall into this
128 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700129 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
131 /*
132 * Leave the last 3% for root
133 */
134 if (!cap_sys_admin)
135 free -= free / 32;
136
137 if (free > pages)
138 return 0;
139
140 /*
141 * nr_free_pages() is very expensive on large systems,
142 * only call if we're about to fail.
143 */
144 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700145
146 /*
147 * Leave reserved pages. The pages are not for anonymous pages.
148 */
149 if (n <= totalreserve_pages)
150 goto error;
151 else
152 n -= totalreserve_pages;
153
154 /*
155 * Leave the last 3% for root
156 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 if (!cap_sys_admin)
158 n -= n / 32;
159 free += n;
160
161 if (free > pages)
162 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700163
164 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 }
166
167 allowed = (totalram_pages - hugetlb_total_pages())
168 * sysctl_overcommit_ratio / 100;
169 /*
170 * Leave the last 3% for root
171 */
172 if (!cap_sys_admin)
173 allowed -= allowed / 32;
174 allowed += total_swap_pages;
175
176 /* Don't let a single process grow too big:
177 leave 3% of the size of this process for other processes */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700178 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
Simon Derr2f60f8d2005-08-04 19:52:03 -0700180 /*
181 * cast `allowed' as a signed long because vm_committed_space
182 * sometimes has a negative value
183 */
Alan Cox80119ef2008-05-23 13:04:31 -0700184 if (atomic_long_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700186error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 vm_unacct_memory(pages);
188
189 return -ENOMEM;
190}
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192/*
193 * Requires inode->i_mapping->i_mmap_lock
194 */
195static void __remove_shared_vm_struct(struct vm_area_struct *vma,
196 struct file *file, struct address_space *mapping)
197{
198 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800199 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 if (vma->vm_flags & VM_SHARED)
201 mapping->i_mmap_writable--;
202
203 flush_dcache_mmap_lock(mapping);
204 if (unlikely(vma->vm_flags & VM_NONLINEAR))
205 list_del_init(&vma->shared.vm_set.list);
206 else
207 vma_prio_tree_remove(vma, &mapping->i_mmap);
208 flush_dcache_mmap_unlock(mapping);
209}
210
211/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700212 * Unlink a file-based vm structure from its prio_tree, to hide
213 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700215void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
217 struct file *file = vma->vm_file;
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (file) {
220 struct address_space *mapping = file->f_mapping;
221 spin_lock(&mapping->i_mmap_lock);
222 __remove_shared_vm_struct(vma, file, mapping);
223 spin_unlock(&mapping->i_mmap_lock);
224 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700225}
226
227/*
228 * Close a vm structure and free it, returning the next.
229 */
230static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
231{
232 struct vm_area_struct *next = vma->vm_next;
233
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700234 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 if (vma->vm_ops && vma->vm_ops->close)
236 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700237 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700238 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700239 if (vma->vm_flags & VM_EXECUTABLE)
240 removed_exe_file_vma(vma->vm_mm);
241 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700242 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700244 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245}
246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247asmlinkage unsigned long sys_brk(unsigned long brk)
248{
249 unsigned long rlim, retval;
250 unsigned long newbrk, oldbrk;
251 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700252 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 down_write(&mm->mmap_sem);
255
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700256#ifdef CONFIG_COMPAT_BRK
257 min_brk = mm->end_code;
258#else
259 min_brk = mm->start_brk;
260#endif
261 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700263
264 /*
265 * Check against rlimit here. If this check is done later after the test
266 * of oldbrk with newbrk then it can escape the test and let the data
267 * segment grow beyond its set limit the in case where the limit is
268 * not page aligned -Ram Gupta
269 */
270 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100271 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
272 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700273 goto out;
274
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 newbrk = PAGE_ALIGN(brk);
276 oldbrk = PAGE_ALIGN(mm->brk);
277 if (oldbrk == newbrk)
278 goto set_brk;
279
280 /* Always allow shrinking brk. */
281 if (brk <= mm->brk) {
282 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
283 goto set_brk;
284 goto out;
285 }
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 /* Check against existing mmap mappings. */
288 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
289 goto out;
290
291 /* Ok, looks good - let it rip. */
292 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
293 goto out;
294set_brk:
295 mm->brk = brk;
296out:
297 retval = mm->brk;
298 up_write(&mm->mmap_sem);
299 return retval;
300}
301
302#ifdef DEBUG_MM_RB
303static int browse_rb(struct rb_root *root)
304{
305 int i = 0, j;
306 struct rb_node *nd, *pn = NULL;
307 unsigned long prev = 0, pend = 0;
308
309 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
310 struct vm_area_struct *vma;
311 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
312 if (vma->vm_start < prev)
313 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
314 if (vma->vm_start < pend)
315 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
316 if (vma->vm_start > vma->vm_end)
317 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
318 i++;
319 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800320 prev = vma->vm_start;
321 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 }
323 j = 0;
324 for (nd = pn; nd; nd = rb_prev(nd)) {
325 j++;
326 }
327 if (i != j)
328 printk("backwards %d, forwards %d\n", j, i), i = 0;
329 return i;
330}
331
332void validate_mm(struct mm_struct *mm)
333{
334 int bug = 0;
335 int i = 0;
336 struct vm_area_struct *tmp = mm->mmap;
337 while (tmp) {
338 tmp = tmp->vm_next;
339 i++;
340 }
341 if (i != mm->map_count)
342 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
343 i = browse_rb(&mm->mm_rb);
344 if (i != mm->map_count)
345 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200346 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347}
348#else
349#define validate_mm(mm) do { } while (0)
350#endif
351
352static struct vm_area_struct *
353find_vma_prepare(struct mm_struct *mm, unsigned long addr,
354 struct vm_area_struct **pprev, struct rb_node ***rb_link,
355 struct rb_node ** rb_parent)
356{
357 struct vm_area_struct * vma;
358 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
359
360 __rb_link = &mm->mm_rb.rb_node;
361 rb_prev = __rb_parent = NULL;
362 vma = NULL;
363
364 while (*__rb_link) {
365 struct vm_area_struct *vma_tmp;
366
367 __rb_parent = *__rb_link;
368 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
369
370 if (vma_tmp->vm_end > addr) {
371 vma = vma_tmp;
372 if (vma_tmp->vm_start <= addr)
373 return vma;
374 __rb_link = &__rb_parent->rb_left;
375 } else {
376 rb_prev = __rb_parent;
377 __rb_link = &__rb_parent->rb_right;
378 }
379 }
380
381 *pprev = NULL;
382 if (rb_prev)
383 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
384 *rb_link = __rb_link;
385 *rb_parent = __rb_parent;
386 return vma;
387}
388
389static inline void
390__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
391 struct vm_area_struct *prev, struct rb_node *rb_parent)
392{
393 if (prev) {
394 vma->vm_next = prev->vm_next;
395 prev->vm_next = vma;
396 } else {
397 mm->mmap = vma;
398 if (rb_parent)
399 vma->vm_next = rb_entry(rb_parent,
400 struct vm_area_struct, vm_rb);
401 else
402 vma->vm_next = NULL;
403 }
404}
405
406void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
407 struct rb_node **rb_link, struct rb_node *rb_parent)
408{
409 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
410 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
411}
412
413static inline void __vma_link_file(struct vm_area_struct *vma)
414{
415 struct file * file;
416
417 file = vma->vm_file;
418 if (file) {
419 struct address_space *mapping = file->f_mapping;
420
421 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800422 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 if (vma->vm_flags & VM_SHARED)
424 mapping->i_mmap_writable++;
425
426 flush_dcache_mmap_lock(mapping);
427 if (unlikely(vma->vm_flags & VM_NONLINEAR))
428 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
429 else
430 vma_prio_tree_insert(vma, &mapping->i_mmap);
431 flush_dcache_mmap_unlock(mapping);
432 }
433}
434
435static void
436__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
437 struct vm_area_struct *prev, struct rb_node **rb_link,
438 struct rb_node *rb_parent)
439{
440 __vma_link_list(mm, vma, prev, rb_parent);
441 __vma_link_rb(mm, vma, rb_link, rb_parent);
442 __anon_vma_link(vma);
443}
444
445static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
446 struct vm_area_struct *prev, struct rb_node **rb_link,
447 struct rb_node *rb_parent)
448{
449 struct address_space *mapping = NULL;
450
451 if (vma->vm_file)
452 mapping = vma->vm_file->f_mapping;
453
454 if (mapping) {
455 spin_lock(&mapping->i_mmap_lock);
456 vma->vm_truncate_count = mapping->truncate_count;
457 }
458 anon_vma_lock(vma);
459
460 __vma_link(mm, vma, prev, rb_link, rb_parent);
461 __vma_link_file(vma);
462
463 anon_vma_unlock(vma);
464 if (mapping)
465 spin_unlock(&mapping->i_mmap_lock);
466
467 mm->map_count++;
468 validate_mm(mm);
469}
470
471/*
472 * Helper for vma_adjust in the split_vma insert case:
473 * insert vm structure into list and rbtree and anon_vma,
474 * but it has already been inserted into prio_tree earlier.
475 */
476static void
477__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
478{
479 struct vm_area_struct * __vma, * prev;
480 struct rb_node ** rb_link, * rb_parent;
481
482 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200483 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 __vma_link(mm, vma, prev, rb_link, rb_parent);
485 mm->map_count++;
486}
487
488static inline void
489__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
490 struct vm_area_struct *prev)
491{
492 prev->vm_next = vma->vm_next;
493 rb_erase(&vma->vm_rb, &mm->mm_rb);
494 if (mm->mmap_cache == vma)
495 mm->mmap_cache = prev;
496}
497
498/*
499 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
500 * is already present in an i_mmap tree without adjusting the tree.
501 * The following helper function should be used when such adjustments
502 * are necessary. The "insert" vma (if any) is to be inserted
503 * before we drop the necessary locks.
504 */
505void vma_adjust(struct vm_area_struct *vma, unsigned long start,
506 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
507{
508 struct mm_struct *mm = vma->vm_mm;
509 struct vm_area_struct *next = vma->vm_next;
510 struct vm_area_struct *importer = NULL;
511 struct address_space *mapping = NULL;
512 struct prio_tree_root *root = NULL;
513 struct file *file = vma->vm_file;
514 struct anon_vma *anon_vma = NULL;
515 long adjust_next = 0;
516 int remove_next = 0;
517
518 if (next && !insert) {
519 if (end >= next->vm_end) {
520 /*
521 * vma expands, overlapping all the next, and
522 * perhaps the one after too (mprotect case 6).
523 */
524again: remove_next = 1 + (end > next->vm_end);
525 end = next->vm_end;
526 anon_vma = next->anon_vma;
527 importer = vma;
528 } else if (end > next->vm_start) {
529 /*
530 * vma expands, overlapping part of the next:
531 * mprotect case 5 shifting the boundary up.
532 */
533 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
534 anon_vma = next->anon_vma;
535 importer = vma;
536 } else if (end < vma->vm_end) {
537 /*
538 * vma shrinks, and !insert tells it's not
539 * split_vma inserting another: so it must be
540 * mprotect case 4 shifting the boundary down.
541 */
542 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
543 anon_vma = next->anon_vma;
544 importer = next;
545 }
546 }
547
548 if (file) {
549 mapping = file->f_mapping;
550 if (!(vma->vm_flags & VM_NONLINEAR))
551 root = &mapping->i_mmap;
552 spin_lock(&mapping->i_mmap_lock);
553 if (importer &&
554 vma->vm_truncate_count != next->vm_truncate_count) {
555 /*
556 * unmap_mapping_range might be in progress:
557 * ensure that the expanding vma is rescanned.
558 */
559 importer->vm_truncate_count = 0;
560 }
561 if (insert) {
562 insert->vm_truncate_count = vma->vm_truncate_count;
563 /*
564 * Put into prio_tree now, so instantiated pages
565 * are visible to arm/parisc __flush_dcache_page
566 * throughout; but we cannot insert into address
567 * space until vma start or end is updated.
568 */
569 __vma_link_file(insert);
570 }
571 }
572
573 /*
574 * When changing only vma->vm_end, we don't really need
575 * anon_vma lock: but is that case worth optimizing out?
576 */
577 if (vma->anon_vma)
578 anon_vma = vma->anon_vma;
579 if (anon_vma) {
580 spin_lock(&anon_vma->lock);
581 /*
582 * Easily overlooked: when mprotect shifts the boundary,
583 * make sure the expanding vma has anon_vma set if the
584 * shrinking vma had, to cover any anon pages imported.
585 */
586 if (importer && !importer->anon_vma) {
587 importer->anon_vma = anon_vma;
588 __anon_vma_link(importer);
589 }
590 }
591
592 if (root) {
593 flush_dcache_mmap_lock(mapping);
594 vma_prio_tree_remove(vma, root);
595 if (adjust_next)
596 vma_prio_tree_remove(next, root);
597 }
598
599 vma->vm_start = start;
600 vma->vm_end = end;
601 vma->vm_pgoff = pgoff;
602 if (adjust_next) {
603 next->vm_start += adjust_next << PAGE_SHIFT;
604 next->vm_pgoff += adjust_next;
605 }
606
607 if (root) {
608 if (adjust_next)
609 vma_prio_tree_insert(next, root);
610 vma_prio_tree_insert(vma, root);
611 flush_dcache_mmap_unlock(mapping);
612 }
613
614 if (remove_next) {
615 /*
616 * vma_merge has merged next into vma, and needs
617 * us to remove next before dropping the locks.
618 */
619 __vma_unlink(mm, next, vma);
620 if (file)
621 __remove_shared_vm_struct(next, file, mapping);
622 if (next->anon_vma)
623 __anon_vma_merge(vma, next);
624 } else if (insert) {
625 /*
626 * split_vma has split insert from vma, and needs
627 * us to insert it before dropping the locks
628 * (it may either follow vma or precede it).
629 */
630 __insert_vm_struct(mm, insert);
631 }
632
633 if (anon_vma)
634 spin_unlock(&anon_vma->lock);
635 if (mapping)
636 spin_unlock(&mapping->i_mmap_lock);
637
638 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700639 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700641 if (next->vm_flags & VM_EXECUTABLE)
642 removed_exe_file_vma(mm);
643 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700645 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 kmem_cache_free(vm_area_cachep, next);
647 /*
648 * In mprotect's case 6 (see comments on vma_merge),
649 * we must remove another next too. It would clutter
650 * up the code too much to do both in one go.
651 */
652 if (remove_next == 2) {
653 next = vma->vm_next;
654 goto again;
655 }
656 }
657
658 validate_mm(mm);
659}
660
661/*
662 * If the vma has a ->close operation then the driver probably needs to release
663 * per-vma resources, so we don't attempt to merge those.
664 */
Hugh Dickinsa6f563d2006-03-22 00:08:29 -0800665#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666
667static inline int is_mergeable_vma(struct vm_area_struct *vma,
668 struct file *file, unsigned long vm_flags)
669{
670 if (vma->vm_flags != vm_flags)
671 return 0;
672 if (vma->vm_file != file)
673 return 0;
674 if (vma->vm_ops && vma->vm_ops->close)
675 return 0;
676 return 1;
677}
678
679static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
680 struct anon_vma *anon_vma2)
681{
682 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
683}
684
685/*
686 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
687 * in front of (at a lower virtual address and file offset than) the vma.
688 *
689 * We cannot merge two vmas if they have differently assigned (non-NULL)
690 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
691 *
692 * We don't check here for the merged mmap wrapping around the end of pagecache
693 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
694 * wrap, nor mmaps which cover the final page at index -1UL.
695 */
696static int
697can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
698 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
699{
700 if (is_mergeable_vma(vma, file, vm_flags) &&
701 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
702 if (vma->vm_pgoff == vm_pgoff)
703 return 1;
704 }
705 return 0;
706}
707
708/*
709 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
710 * beyond (at a higher virtual address and file offset than) the vma.
711 *
712 * We cannot merge two vmas if they have differently assigned (non-NULL)
713 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
714 */
715static int
716can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
717 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
718{
719 if (is_mergeable_vma(vma, file, vm_flags) &&
720 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
721 pgoff_t vm_pglen;
722 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
723 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
724 return 1;
725 }
726 return 0;
727}
728
729/*
730 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
731 * whether that can be merged with its predecessor or its successor.
732 * Or both (it neatly fills a hole).
733 *
734 * In most cases - when called for mmap, brk or mremap - [addr,end) is
735 * certain not to be mapped by the time vma_merge is called; but when
736 * called for mprotect, it is certain to be already mapped (either at
737 * an offset within prev, or at the start of next), and the flags of
738 * this area are about to be changed to vm_flags - and the no-change
739 * case has already been eliminated.
740 *
741 * The following mprotect cases have to be considered, where AAAA is
742 * the area passed down from mprotect_fixup, never extending beyond one
743 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
744 *
745 * AAAA AAAA AAAA AAAA
746 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
747 * cannot merge might become might become might become
748 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
749 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
750 * mremap move: PPPPNNNNNNNN 8
751 * AAAA
752 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
753 * might become case 1 below case 2 below case 3 below
754 *
755 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
756 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
757 */
758struct vm_area_struct *vma_merge(struct mm_struct *mm,
759 struct vm_area_struct *prev, unsigned long addr,
760 unsigned long end, unsigned long vm_flags,
761 struct anon_vma *anon_vma, struct file *file,
762 pgoff_t pgoff, struct mempolicy *policy)
763{
764 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
765 struct vm_area_struct *area, *next;
766
767 /*
768 * We later require that vma->vm_flags == vm_flags,
769 * so this tests vma->vm_flags & VM_SPECIAL, too.
770 */
771 if (vm_flags & VM_SPECIAL)
772 return NULL;
773
774 if (prev)
775 next = prev->vm_next;
776 else
777 next = mm->mmap;
778 area = next;
779 if (next && next->vm_end == end) /* cases 6, 7, 8 */
780 next = next->vm_next;
781
782 /*
783 * Can it merge with the predecessor?
784 */
785 if (prev && prev->vm_end == addr &&
786 mpol_equal(vma_policy(prev), policy) &&
787 can_vma_merge_after(prev, vm_flags,
788 anon_vma, file, pgoff)) {
789 /*
790 * OK, it can. Can we now merge in the successor as well?
791 */
792 if (next && end == next->vm_start &&
793 mpol_equal(policy, vma_policy(next)) &&
794 can_vma_merge_before(next, vm_flags,
795 anon_vma, file, pgoff+pglen) &&
796 is_mergeable_anon_vma(prev->anon_vma,
797 next->anon_vma)) {
798 /* cases 1, 6 */
799 vma_adjust(prev, prev->vm_start,
800 next->vm_end, prev->vm_pgoff, NULL);
801 } else /* cases 2, 5, 7 */
802 vma_adjust(prev, prev->vm_start,
803 end, prev->vm_pgoff, NULL);
804 return prev;
805 }
806
807 /*
808 * Can this new request be merged in front of next?
809 */
810 if (next && end == next->vm_start &&
811 mpol_equal(policy, vma_policy(next)) &&
812 can_vma_merge_before(next, vm_flags,
813 anon_vma, file, pgoff+pglen)) {
814 if (prev && addr < prev->vm_end) /* case 4 */
815 vma_adjust(prev, prev->vm_start,
816 addr, prev->vm_pgoff, NULL);
817 else /* cases 3, 8 */
818 vma_adjust(area, addr, next->vm_end,
819 next->vm_pgoff - pglen, NULL);
820 return area;
821 }
822
823 return NULL;
824}
825
826/*
827 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
828 * neighbouring vmas for a suitable anon_vma, before it goes off
829 * to allocate a new anon_vma. It checks because a repetitive
830 * sequence of mprotects and faults may otherwise lead to distinct
831 * anon_vmas being allocated, preventing vma merge in subsequent
832 * mprotect.
833 */
834struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
835{
836 struct vm_area_struct *near;
837 unsigned long vm_flags;
838
839 near = vma->vm_next;
840 if (!near)
841 goto try_prev;
842
843 /*
844 * Since only mprotect tries to remerge vmas, match flags
845 * which might be mprotected into each other later on.
846 * Neither mlock nor madvise tries to remerge at present,
847 * so leave their flags as obstructing a merge.
848 */
849 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
850 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
851
852 if (near->anon_vma && vma->vm_end == near->vm_start &&
853 mpol_equal(vma_policy(vma), vma_policy(near)) &&
854 can_vma_merge_before(near, vm_flags,
855 NULL, vma->vm_file, vma->vm_pgoff +
856 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
857 return near->anon_vma;
858try_prev:
859 /*
860 * It is potentially slow to have to call find_vma_prev here.
861 * But it's only on the first write fault on the vma, not
862 * every time, and we could devise a way to avoid it later
863 * (e.g. stash info in next's anon_vma_node when assigning
864 * an anon_vma, or when trying vma_merge). Another time.
865 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200866 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 if (!near)
868 goto none;
869
870 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
871 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
872
873 if (near->anon_vma && near->vm_end == vma->vm_start &&
874 mpol_equal(vma_policy(near), vma_policy(vma)) &&
875 can_vma_merge_after(near, vm_flags,
876 NULL, vma->vm_file, vma->vm_pgoff))
877 return near->anon_vma;
878none:
879 /*
880 * There's no absolute need to look only at touching neighbours:
881 * we could search further afield for "compatible" anon_vmas.
882 * But it would probably just be a waste of time searching,
883 * or lead to too many vmas hanging off the same anon_vma.
884 * We're trying to allow mprotect remerging later on,
885 * not trying to minimize memory used for anon_vmas.
886 */
887 return NULL;
888}
889
890#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700891void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 struct file *file, long pages)
893{
894 const unsigned long stack_flags
895 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
896
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 if (file) {
898 mm->shared_vm += pages;
899 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
900 mm->exec_vm += pages;
901 } else if (flags & stack_flags)
902 mm->stack_vm += pages;
903 if (flags & (VM_RESERVED|VM_IO))
904 mm->reserved_vm += pages;
905}
906#endif /* CONFIG_PROC_FS */
907
908/*
909 * The caller must hold down_write(current->mm->mmap_sem).
910 */
911
912unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
913 unsigned long len, unsigned long prot,
914 unsigned long flags, unsigned long pgoff)
915{
916 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 struct inode *inode;
918 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 int accountable = 1;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700921 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 /*
924 * Does the application expect PROT_READ to imply PROT_EXEC?
925 *
926 * (the exception is when the underlying filesystem is noexec
927 * mounted, in which case we dont add PROT_EXEC.)
928 */
929 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800930 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 prot |= PROT_EXEC;
932
933 if (!len)
934 return -EINVAL;
935
Eric Paris7cd94142007-11-26 18:47:40 -0500936 if (!(flags & MAP_FIXED))
937 addr = round_hint_to_min(addr);
938
Kirill Korotaev3a459752006-09-07 14:17:04 +0400939 error = arch_mmap_check(addr, len, flags);
940 if (error)
941 return error;
942
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 /* Careful about overflows.. */
944 len = PAGE_ALIGN(len);
945 if (!len || len > TASK_SIZE)
946 return -ENOMEM;
947
948 /* offset overflow? */
949 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
950 return -EOVERFLOW;
951
952 /* Too many mappings? */
953 if (mm->map_count > sysctl_max_map_count)
954 return -ENOMEM;
955
956 /* Obtain the address to map to. we verify (or select) it and ensure
957 * that it represents a valid section of the address space.
958 */
959 addr = get_unmapped_area(file, addr, len, pgoff, flags);
960 if (addr & ~PAGE_MASK)
961 return addr;
962
963 /* Do simple checking here so the lower-level routines won't have
964 * to. we assume access permissions have been handled by the open
965 * of the memory object, so we don't do any here.
966 */
967 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
968 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
969
970 if (flags & MAP_LOCKED) {
971 if (!can_do_mlock())
972 return -EPERM;
973 vm_flags |= VM_LOCKED;
974 }
975 /* mlock MCL_FUTURE? */
976 if (vm_flags & VM_LOCKED) {
977 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700978 locked = len >> PAGE_SHIFT;
979 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700981 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
983 return -EAGAIN;
984 }
985
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800986 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987
988 if (file) {
989 switch (flags & MAP_TYPE) {
990 case MAP_SHARED:
991 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
992 return -EACCES;
993
994 /*
995 * Make sure we don't allow writing to an append-only
996 * file..
997 */
998 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
999 return -EACCES;
1000
1001 /*
1002 * Make sure there are no mandatory locks on the file.
1003 */
1004 if (locks_verify_locked(inode))
1005 return -EAGAIN;
1006
1007 vm_flags |= VM_SHARED | VM_MAYSHARE;
1008 if (!(file->f_mode & FMODE_WRITE))
1009 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1010
1011 /* fall through */
1012 case MAP_PRIVATE:
1013 if (!(file->f_mode & FMODE_READ))
1014 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001015 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001016 if (vm_flags & VM_EXEC)
1017 return -EPERM;
1018 vm_flags &= ~VM_MAYEXEC;
1019 }
1020 if (is_file_hugepages(file))
1021 accountable = 0;
1022
1023 if (!file->f_op || !file->f_op->mmap)
1024 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 break;
1026
1027 default:
1028 return -EINVAL;
1029 }
1030 } else {
1031 switch (flags & MAP_TYPE) {
1032 case MAP_SHARED:
1033 vm_flags |= VM_SHARED | VM_MAYSHARE;
1034 break;
1035 case MAP_PRIVATE:
1036 /*
1037 * Set pgoff according to addr for anon_vma.
1038 */
1039 pgoff = addr >> PAGE_SHIFT;
1040 break;
1041 default:
1042 return -EINVAL;
1043 }
1044 }
1045
Eric Parised032182007-06-28 15:55:21 -04001046 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 if (error)
1048 return error;
Eric Parised032182007-06-28 15:55:21 -04001049
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001050 return mmap_region(file, addr, len, flags, vm_flags, pgoff,
1051 accountable);
1052}
1053EXPORT_SYMBOL(do_mmap_pgoff);
1054
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001055/*
1056 * Some shared mappigns will want the pages marked read-only
1057 * to track write events. If so, we'll downgrade vm_page_prot
1058 * to the private version (using protection_map[] without the
1059 * VM_SHARED bit).
1060 */
1061int vma_wants_writenotify(struct vm_area_struct *vma)
1062{
1063 unsigned int vm_flags = vma->vm_flags;
1064
1065 /* If it was private or non-writable, the write bit is already clear */
1066 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1067 return 0;
1068
1069 /* The backer wishes to know when pages are first written to? */
1070 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1071 return 1;
1072
1073 /* The open routine did something to the protections already? */
1074 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001075 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001076 return 0;
1077
1078 /* Specialty mapping? */
1079 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1080 return 0;
1081
1082 /* Can the mapping track the dirty pages? */
1083 return vma->vm_file && vma->vm_file->f_mapping &&
1084 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1085}
1086
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001087unsigned long mmap_region(struct file *file, unsigned long addr,
1088 unsigned long len, unsigned long flags,
1089 unsigned int vm_flags, unsigned long pgoff,
1090 int accountable)
1091{
1092 struct mm_struct *mm = current->mm;
1093 struct vm_area_struct *vma, *prev;
1094 int correct_wcount = 0;
1095 int error;
1096 struct rb_node **rb_link, *rb_parent;
1097 unsigned long charged = 0;
1098 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1099
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 /* Clear old maps */
1101 error = -ENOMEM;
1102munmap_back:
1103 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1104 if (vma && vma->vm_start < addr + len) {
1105 if (do_munmap(mm, addr, len))
1106 return -ENOMEM;
1107 goto munmap_back;
1108 }
1109
1110 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001111 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 return -ENOMEM;
1113
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001114 if (flags & MAP_NORESERVE)
1115 vm_flags |= VM_NORESERVE;
1116
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 if (accountable && (!(flags & MAP_NORESERVE) ||
1118 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1119 if (vm_flags & VM_SHARED) {
1120 /* Check memory availability in shmem_file_setup? */
1121 vm_flags |= VM_ACCOUNT;
1122 } else if (vm_flags & VM_WRITE) {
1123 /*
1124 * Private writable mapping: check memory availability
1125 */
1126 charged = len >> PAGE_SHIFT;
1127 if (security_vm_enough_memory(charged))
1128 return -ENOMEM;
1129 vm_flags |= VM_ACCOUNT;
1130 }
1131 }
1132
1133 /*
1134 * Can we just expand an old private anonymous mapping?
1135 * The VM_SHARED test is necessary because shmem_zero_setup
1136 * will create the file object for a shared anonymous map below.
1137 */
1138 if (!file && !(vm_flags & VM_SHARED) &&
1139 vma_merge(mm, prev, addr, addr + len, vm_flags,
1140 NULL, NULL, pgoff, NULL))
1141 goto out;
1142
1143 /*
1144 * Determine the object being mapped and call the appropriate
1145 * specific mapper. the address has already been validated, but
1146 * not unmapped, but the maps are removed from the list.
1147 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001148 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 if (!vma) {
1150 error = -ENOMEM;
1151 goto unacct_error;
1152 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153
1154 vma->vm_mm = mm;
1155 vma->vm_start = addr;
1156 vma->vm_end = addr + len;
1157 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001158 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 vma->vm_pgoff = pgoff;
1160
1161 if (file) {
1162 error = -EINVAL;
1163 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1164 goto free_vma;
1165 if (vm_flags & VM_DENYWRITE) {
1166 error = deny_write_access(file);
1167 if (error)
1168 goto free_vma;
1169 correct_wcount = 1;
1170 }
1171 vma->vm_file = file;
1172 get_file(file);
1173 error = file->f_op->mmap(file, vma);
1174 if (error)
1175 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001176 if (vm_flags & VM_EXECUTABLE)
1177 added_exe_file_vma(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 } else if (vm_flags & VM_SHARED) {
1179 error = shmem_zero_setup(vma);
1180 if (error)
1181 goto free_vma;
1182 }
1183
1184 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1185 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1186 * that memory reservation must be checked; but that reservation
1187 * belongs to shared memory object, not to vma: so now clear it.
1188 */
1189 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1190 vma->vm_flags &= ~VM_ACCOUNT;
1191
1192 /* Can addr have changed??
1193 *
1194 * Answer: Yes, several device drivers can do it in their
1195 * f_op->mmap method. -DaveM
1196 */
1197 addr = vma->vm_start;
1198 pgoff = vma->vm_pgoff;
1199 vm_flags = vma->vm_flags;
1200
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001201 if (vma_wants_writenotify(vma))
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001202 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001203
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001204 if (file && vma_merge(mm, prev, addr, vma->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
Lee Schermerhornf0be3d32008-04-28 02:13:08 -07001206 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 kmem_cache_free(vm_area_cachep, vma);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001208 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001209 if (vm_flags & VM_EXECUTABLE)
1210 removed_exe_file_vma(mm);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001211 } else {
1212 vma_link(mm, vma, prev, rb_link, rb_parent);
1213 file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 }
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001215
1216 /* Once vma denies write, undo our temporary denial count */
1217 if (correct_wcount)
1218 atomic_inc(&inode->i_writecount);
1219out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001221 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 if (vm_flags & VM_LOCKED) {
1223 mm->locked_vm += len >> PAGE_SHIFT;
1224 make_pages_present(addr, addr + len);
1225 }
Nick Piggin54cb8822007-07-19 01:46:59 -07001226 if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1227 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 return addr;
1229
1230unmap_and_free_vma:
1231 if (correct_wcount)
1232 atomic_inc(&inode->i_writecount);
1233 vma->vm_file = NULL;
1234 fput(file);
1235
1236 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001237 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1238 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239free_vma:
1240 kmem_cache_free(vm_area_cachep, vma);
1241unacct_error:
1242 if (charged)
1243 vm_unacct_memory(charged);
1244 return error;
1245}
1246
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247/* Get an address range which is currently unmapped.
1248 * For shmat() with addr=0.
1249 *
1250 * Ugly calling convention alert:
1251 * Return value with the low bits set means error value,
1252 * ie
1253 * if (ret & ~PAGE_MASK)
1254 * error = ret;
1255 *
1256 * This function "knows" that -ENOMEM has the bits set.
1257 */
1258#ifndef HAVE_ARCH_UNMAPPED_AREA
1259unsigned long
1260arch_get_unmapped_area(struct file *filp, unsigned long addr,
1261 unsigned long len, unsigned long pgoff, unsigned long flags)
1262{
1263 struct mm_struct *mm = current->mm;
1264 struct vm_area_struct *vma;
1265 unsigned long start_addr;
1266
1267 if (len > TASK_SIZE)
1268 return -ENOMEM;
1269
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001270 if (flags & MAP_FIXED)
1271 return addr;
1272
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 if (addr) {
1274 addr = PAGE_ALIGN(addr);
1275 vma = find_vma(mm, addr);
1276 if (TASK_SIZE - len >= addr &&
1277 (!vma || addr + len <= vma->vm_start))
1278 return addr;
1279 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001280 if (len > mm->cached_hole_size) {
1281 start_addr = addr = mm->free_area_cache;
1282 } else {
1283 start_addr = addr = TASK_UNMAPPED_BASE;
1284 mm->cached_hole_size = 0;
1285 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286
1287full_search:
1288 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1289 /* At this point: (!vma || addr < vma->vm_end). */
1290 if (TASK_SIZE - len < addr) {
1291 /*
1292 * Start a new search - just in case we missed
1293 * some holes.
1294 */
1295 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001296 addr = TASK_UNMAPPED_BASE;
1297 start_addr = addr;
1298 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 goto full_search;
1300 }
1301 return -ENOMEM;
1302 }
1303 if (!vma || addr + len <= vma->vm_start) {
1304 /*
1305 * Remember the place where we stopped the search:
1306 */
1307 mm->free_area_cache = addr + len;
1308 return addr;
1309 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001310 if (addr + mm->cached_hole_size < vma->vm_start)
1311 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 addr = vma->vm_end;
1313 }
1314}
1315#endif
1316
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001317void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318{
1319 /*
1320 * Is this a new hole at the lowest possible address?
1321 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001322 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1323 mm->free_area_cache = addr;
1324 mm->cached_hole_size = ~0UL;
1325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326}
1327
1328/*
1329 * This mmap-allocator allocates new areas top-down from below the
1330 * stack's low limit (the base):
1331 */
1332#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1333unsigned long
1334arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1335 const unsigned long len, const unsigned long pgoff,
1336 const unsigned long flags)
1337{
1338 struct vm_area_struct *vma;
1339 struct mm_struct *mm = current->mm;
1340 unsigned long addr = addr0;
1341
1342 /* requested length too big for entire address space */
1343 if (len > TASK_SIZE)
1344 return -ENOMEM;
1345
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001346 if (flags & MAP_FIXED)
1347 return addr;
1348
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 /* requesting a specific address */
1350 if (addr) {
1351 addr = PAGE_ALIGN(addr);
1352 vma = find_vma(mm, addr);
1353 if (TASK_SIZE - len >= addr &&
1354 (!vma || addr + len <= vma->vm_start))
1355 return addr;
1356 }
1357
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001358 /* check if free_area_cache is useful for us */
1359 if (len <= mm->cached_hole_size) {
1360 mm->cached_hole_size = 0;
1361 mm->free_area_cache = mm->mmap_base;
1362 }
1363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 /* either no address requested or can't fit in requested address hole */
1365 addr = mm->free_area_cache;
1366
1367 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001368 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 vma = find_vma(mm, addr-len);
1370 if (!vma || addr <= vma->vm_start)
1371 /* remember the address as a hint for next time */
1372 return (mm->free_area_cache = addr-len);
1373 }
1374
Chris Wright73219d12005-06-21 17:14:52 -07001375 if (mm->mmap_base < len)
1376 goto bottomup;
1377
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378 addr = mm->mmap_base-len;
1379
1380 do {
1381 /*
1382 * Lookup failure means no vma is above this address,
1383 * else if new region fits below vma->vm_start,
1384 * return with success:
1385 */
1386 vma = find_vma(mm, addr);
1387 if (!vma || addr+len <= vma->vm_start)
1388 /* remember the address as a hint for next time */
1389 return (mm->free_area_cache = addr);
1390
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001391 /* remember the largest hole we saw so far */
1392 if (addr + mm->cached_hole_size < vma->vm_start)
1393 mm->cached_hole_size = vma->vm_start - addr;
1394
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 /* try just below the current vma->vm_start */
1396 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001397 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398
Chris Wright73219d12005-06-21 17:14:52 -07001399bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 /*
1401 * A failed mmap() very likely causes application failure,
1402 * so fall back to the bottom-up function here. This scenario
1403 * can happen with large stack limits and large mmap()
1404 * allocations.
1405 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001406 mm->cached_hole_size = ~0UL;
1407 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1409 /*
1410 * Restore the topdown base:
1411 */
1412 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001413 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
1415 return addr;
1416}
1417#endif
1418
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001419void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420{
1421 /*
1422 * Is this a new hole at the highest possible address?
1423 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001424 if (addr > mm->free_area_cache)
1425 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
1427 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001428 if (mm->free_area_cache > mm->mmap_base)
1429 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430}
1431
1432unsigned long
1433get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1434 unsigned long pgoff, unsigned long flags)
1435{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001436 unsigned long (*get_area)(struct file *, unsigned long,
1437 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001439 get_area = current->mm->get_unmapped_area;
1440 if (file && file->f_op && file->f_op->get_unmapped_area)
1441 get_area = file->f_op->get_unmapped_area;
1442 addr = get_area(file, addr, len, pgoff, flags);
1443 if (IS_ERR_VALUE(addr))
1444 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001446 if (addr > TASK_SIZE - len)
1447 return -ENOMEM;
1448 if (addr & ~PAGE_MASK)
1449 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001450
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001451 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452}
1453
1454EXPORT_SYMBOL(get_unmapped_area);
1455
1456/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1457struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1458{
1459 struct vm_area_struct *vma = NULL;
1460
1461 if (mm) {
1462 /* Check the cache first. */
1463 /* (Cache hit rate is typically around 35%.) */
1464 vma = mm->mmap_cache;
1465 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1466 struct rb_node * rb_node;
1467
1468 rb_node = mm->mm_rb.rb_node;
1469 vma = NULL;
1470
1471 while (rb_node) {
1472 struct vm_area_struct * vma_tmp;
1473
1474 vma_tmp = rb_entry(rb_node,
1475 struct vm_area_struct, vm_rb);
1476
1477 if (vma_tmp->vm_end > addr) {
1478 vma = vma_tmp;
1479 if (vma_tmp->vm_start <= addr)
1480 break;
1481 rb_node = rb_node->rb_left;
1482 } else
1483 rb_node = rb_node->rb_right;
1484 }
1485 if (vma)
1486 mm->mmap_cache = vma;
1487 }
1488 }
1489 return vma;
1490}
1491
1492EXPORT_SYMBOL(find_vma);
1493
1494/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1495struct vm_area_struct *
1496find_vma_prev(struct mm_struct *mm, unsigned long addr,
1497 struct vm_area_struct **pprev)
1498{
1499 struct vm_area_struct *vma = NULL, *prev = NULL;
1500 struct rb_node * rb_node;
1501 if (!mm)
1502 goto out;
1503
1504 /* Guard against addr being lower than the first VMA */
1505 vma = mm->mmap;
1506
1507 /* Go through the RB tree quickly. */
1508 rb_node = mm->mm_rb.rb_node;
1509
1510 while (rb_node) {
1511 struct vm_area_struct *vma_tmp;
1512 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1513
1514 if (addr < vma_tmp->vm_end) {
1515 rb_node = rb_node->rb_left;
1516 } else {
1517 prev = vma_tmp;
1518 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1519 break;
1520 rb_node = rb_node->rb_right;
1521 }
1522 }
1523
1524out:
1525 *pprev = prev;
1526 return prev ? prev->vm_next : vma;
1527}
1528
1529/*
1530 * Verify that the stack growth is acceptable and
1531 * update accounting. This is shared with both the
1532 * grow-up and grow-down cases.
1533 */
1534static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1535{
1536 struct mm_struct *mm = vma->vm_mm;
1537 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001538 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539
1540 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001541 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 return -ENOMEM;
1543
1544 /* Stack limit test */
1545 if (size > rlim[RLIMIT_STACK].rlim_cur)
1546 return -ENOMEM;
1547
1548 /* mlock limit tests */
1549 if (vma->vm_flags & VM_LOCKED) {
1550 unsigned long locked;
1551 unsigned long limit;
1552 locked = mm->locked_vm + grow;
1553 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1554 if (locked > limit && !capable(CAP_IPC_LOCK))
1555 return -ENOMEM;
1556 }
1557
Adam Litke0d59a012007-01-30 14:35:39 -08001558 /* Check to ensure the stack will not grow into a hugetlb-only region */
1559 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1560 vma->vm_end - size;
1561 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1562 return -EFAULT;
1563
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564 /*
1565 * Overcommit.. This must be the final test, as it will
1566 * update security statistics.
1567 */
1568 if (security_vm_enough_memory(grow))
1569 return -ENOMEM;
1570
1571 /* Ok, everything looks good - let it rip */
1572 mm->total_vm += grow;
1573 if (vma->vm_flags & VM_LOCKED)
1574 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001575 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 return 0;
1577}
1578
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001579#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001581 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1582 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001584#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001585static inline
1586#endif
1587int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588{
1589 int error;
1590
1591 if (!(vma->vm_flags & VM_GROWSUP))
1592 return -EFAULT;
1593
1594 /*
1595 * We must make sure the anon_vma is allocated
1596 * so that the anon_vma locking is not a noop.
1597 */
1598 if (unlikely(anon_vma_prepare(vma)))
1599 return -ENOMEM;
1600 anon_vma_lock(vma);
1601
1602 /*
1603 * vma->vm_start/vm_end cannot change under us because the caller
1604 * is required to hold the mmap_sem in read mode. We need the
1605 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001606 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 */
Helge Deller06b32f32006-12-19 19:28:33 +01001608 if (address < PAGE_ALIGN(address+4))
1609 address = PAGE_ALIGN(address+4);
1610 else {
1611 anon_vma_unlock(vma);
1612 return -ENOMEM;
1613 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614 error = 0;
1615
1616 /* Somebody else might have raced and expanded it already */
1617 if (address > vma->vm_end) {
1618 unsigned long size, grow;
1619
1620 size = address - vma->vm_start;
1621 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1622
1623 error = acct_stack_growth(vma, size, grow);
1624 if (!error)
1625 vma->vm_end = address;
1626 }
1627 anon_vma_unlock(vma);
1628 return error;
1629}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001630#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1631
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632/*
1633 * vma is the first one with address < vma->vm_start. Have to extend vma.
1634 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001635static inline int expand_downwards(struct vm_area_struct *vma,
1636 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637{
1638 int error;
1639
1640 /*
1641 * We must make sure the anon_vma is allocated
1642 * so that the anon_vma locking is not a noop.
1643 */
1644 if (unlikely(anon_vma_prepare(vma)))
1645 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001646
1647 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001648 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001649 if (error)
1650 return error;
1651
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 anon_vma_lock(vma);
1653
1654 /*
1655 * vma->vm_start/vm_end cannot change under us because the caller
1656 * is required to hold the mmap_sem in read mode. We need the
1657 * anon_vma lock to serialize against concurrent expand_stacks.
1658 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659
1660 /* Somebody else might have raced and expanded it already */
1661 if (address < vma->vm_start) {
1662 unsigned long size, grow;
1663
1664 size = vma->vm_end - address;
1665 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1666
1667 error = acct_stack_growth(vma, size, grow);
1668 if (!error) {
1669 vma->vm_start = address;
1670 vma->vm_pgoff -= grow;
1671 }
1672 }
1673 anon_vma_unlock(vma);
1674 return error;
1675}
1676
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001677int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1678{
1679 return expand_downwards(vma, address);
1680}
1681
1682#ifdef CONFIG_STACK_GROWSUP
1683int expand_stack(struct vm_area_struct *vma, unsigned long address)
1684{
1685 return expand_upwards(vma, address);
1686}
1687
1688struct vm_area_struct *
1689find_extend_vma(struct mm_struct *mm, unsigned long addr)
1690{
1691 struct vm_area_struct *vma, *prev;
1692
1693 addr &= PAGE_MASK;
1694 vma = find_vma_prev(mm, addr, &prev);
1695 if (vma && (vma->vm_start <= addr))
1696 return vma;
1697 if (!prev || expand_stack(prev, addr))
1698 return NULL;
1699 if (prev->vm_flags & VM_LOCKED)
1700 make_pages_present(addr, prev->vm_end);
1701 return prev;
1702}
1703#else
1704int expand_stack(struct vm_area_struct *vma, unsigned long address)
1705{
1706 return expand_downwards(vma, address);
1707}
1708
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709struct vm_area_struct *
1710find_extend_vma(struct mm_struct * mm, unsigned long addr)
1711{
1712 struct vm_area_struct * vma;
1713 unsigned long start;
1714
1715 addr &= PAGE_MASK;
1716 vma = find_vma(mm,addr);
1717 if (!vma)
1718 return NULL;
1719 if (vma->vm_start <= addr)
1720 return vma;
1721 if (!(vma->vm_flags & VM_GROWSDOWN))
1722 return NULL;
1723 start = vma->vm_start;
1724 if (expand_stack(vma, addr))
1725 return NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001726 if (vma->vm_flags & VM_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727 make_pages_present(addr, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 return vma;
1729}
1730#endif
1731
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001733 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001735 *
1736 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001738static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001740 /* Update high watermark before we lower total_vm */
1741 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001743 long nrpages = vma_pages(vma);
1744
1745 mm->total_vm -= nrpages;
1746 if (vma->vm_flags & VM_LOCKED)
1747 mm->locked_vm -= nrpages;
1748 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001749 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001750 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 validate_mm(mm);
1752}
1753
1754/*
1755 * Get rid of page table information in the indicated region.
1756 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001757 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758 */
1759static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001760 struct vm_area_struct *vma, struct vm_area_struct *prev,
1761 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001763 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 struct mmu_gather *tlb;
1765 unsigned long nr_accounted = 0;
1766
1767 lru_add_drain();
1768 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001769 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001770 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07001772 free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001773 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 tlb_finish_mmu(tlb, start, end);
1775}
1776
1777/*
1778 * Create a list of vma's touched by the unmap, removing them from the mm's
1779 * vma list as we go..
1780 */
1781static void
1782detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1783 struct vm_area_struct *prev, unsigned long end)
1784{
1785 struct vm_area_struct **insertion_point;
1786 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001787 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788
1789 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1790 do {
1791 rb_erase(&vma->vm_rb, &mm->mm_rb);
1792 mm->map_count--;
1793 tail_vma = vma;
1794 vma = vma->vm_next;
1795 } while (vma && vma->vm_start < end);
1796 *insertion_point = vma;
1797 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001798 if (mm->unmap_area == arch_unmap_area)
1799 addr = prev ? prev->vm_end : mm->mmap_base;
1800 else
1801 addr = vma ? vma->vm_start : mm->mmap_base;
1802 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 mm->mmap_cache = NULL; /* Kill the cache. */
1804}
1805
1806/*
1807 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001808 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 */
1810int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1811 unsigned long addr, int new_below)
1812{
1813 struct mempolicy *pol;
1814 struct vm_area_struct *new;
1815
Andi Kleena5516432008-07-23 21:27:41 -07001816 if (is_vm_hugetlb_page(vma) && (addr &
1817 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818 return -EINVAL;
1819
1820 if (mm->map_count >= sysctl_max_map_count)
1821 return -ENOMEM;
1822
Christoph Lametere94b1762006-12-06 20:33:17 -08001823 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 if (!new)
1825 return -ENOMEM;
1826
1827 /* most fields are the same, copy all, and then fixup */
1828 *new = *vma;
1829
1830 if (new_below)
1831 new->vm_end = addr;
1832 else {
1833 new->vm_start = addr;
1834 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1835 }
1836
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001837 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 if (IS_ERR(pol)) {
1839 kmem_cache_free(vm_area_cachep, new);
1840 return PTR_ERR(pol);
1841 }
1842 vma_set_policy(new, pol);
1843
Matt Helsley925d1c42008-04-29 01:01:36 -07001844 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001846 if (vma->vm_flags & VM_EXECUTABLE)
1847 added_exe_file_vma(mm);
1848 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849
1850 if (new->vm_ops && new->vm_ops->open)
1851 new->vm_ops->open(new);
1852
1853 if (new_below)
1854 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1855 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1856 else
1857 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1858
1859 return 0;
1860}
1861
1862/* Munmap is split into 2 main parts -- this part which finds
1863 * what needs doing, and the areas themselves, which do the
1864 * work. This now handles partial unmappings.
1865 * Jeremy Fitzhardinge <jeremy@goop.org>
1866 */
1867int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1868{
1869 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001870 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871
1872 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1873 return -EINVAL;
1874
1875 if ((len = PAGE_ALIGN(len)) == 0)
1876 return -EINVAL;
1877
1878 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001879 vma = find_vma_prev(mm, start, &prev);
1880 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001882 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883
1884 /* if it doesn't overlap, we have nothing.. */
1885 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001886 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 return 0;
1888
1889 /*
1890 * If we need to split any vma, do it now to save pain later.
1891 *
1892 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1893 * unmapped vm_area_struct will remain in use: so lower split_vma
1894 * places tmp vma above, and higher split_vma places tmp vma below.
1895 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001896 if (start > vma->vm_start) {
1897 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 if (error)
1899 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001900 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 }
1902
1903 /* Does it split the last one? */
1904 last = find_vma(mm, end);
1905 if (last && end > last->vm_start) {
1906 int error = split_vma(mm, last, end, 1);
1907 if (error)
1908 return error;
1909 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001910 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911
1912 /*
1913 * Remove the vma's, and unmap the actual pages
1914 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001915 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1916 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917
1918 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001919 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920
1921 return 0;
1922}
1923
1924EXPORT_SYMBOL(do_munmap);
1925
1926asmlinkage long sys_munmap(unsigned long addr, size_t len)
1927{
1928 int ret;
1929 struct mm_struct *mm = current->mm;
1930
1931 profile_munmap(addr);
1932
1933 down_write(&mm->mmap_sem);
1934 ret = do_munmap(mm, addr, len);
1935 up_write(&mm->mmap_sem);
1936 return ret;
1937}
1938
1939static inline void verify_mm_writelocked(struct mm_struct *mm)
1940{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001941#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1943 WARN_ON(1);
1944 up_read(&mm->mmap_sem);
1945 }
1946#endif
1947}
1948
1949/*
1950 * this is really a simplified "do_mmap". it only handles
1951 * anonymous maps. eventually we may be able to do some
1952 * brk-specific accounting here.
1953 */
1954unsigned long do_brk(unsigned long addr, unsigned long len)
1955{
1956 struct mm_struct * mm = current->mm;
1957 struct vm_area_struct * vma, * prev;
1958 unsigned long flags;
1959 struct rb_node ** rb_link, * rb_parent;
1960 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001961 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962
1963 len = PAGE_ALIGN(len);
1964 if (!len)
1965 return addr;
1966
1967 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1968 return -EINVAL;
1969
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001970 if (is_hugepage_only_range(mm, addr, len))
1971 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001972
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001973 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05001974 if (error)
1975 return error;
1976
Kirill Korotaev3a459752006-09-07 14:17:04 +04001977 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1978
1979 error = arch_mmap_check(addr, len, flags);
1980 if (error)
1981 return error;
1982
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983 /*
1984 * mlock MCL_FUTURE?
1985 */
1986 if (mm->def_flags & VM_LOCKED) {
1987 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001988 locked = len >> PAGE_SHIFT;
1989 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001991 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1993 return -EAGAIN;
1994 }
1995
1996 /*
1997 * mm->mmap_sem is required to protect against another thread
1998 * changing the mappings in case we sleep.
1999 */
2000 verify_mm_writelocked(mm);
2001
2002 /*
2003 * Clear old maps. this also does some error checking for us
2004 */
2005 munmap_back:
2006 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2007 if (vma && vma->vm_start < addr + len) {
2008 if (do_munmap(mm, addr, len))
2009 return -ENOMEM;
2010 goto munmap_back;
2011 }
2012
2013 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002014 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015 return -ENOMEM;
2016
2017 if (mm->map_count > sysctl_max_map_count)
2018 return -ENOMEM;
2019
2020 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2021 return -ENOMEM;
2022
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 /* Can we just expand an old private anonymous mapping? */
2024 if (vma_merge(mm, prev, addr, addr + len, flags,
2025 NULL, NULL, pgoff, NULL))
2026 goto out;
2027
2028 /*
2029 * create a vma struct for an anonymous mapping
2030 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002031 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032 if (!vma) {
2033 vm_unacct_memory(len >> PAGE_SHIFT);
2034 return -ENOMEM;
2035 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036
2037 vma->vm_mm = mm;
2038 vma->vm_start = addr;
2039 vma->vm_end = addr + len;
2040 vma->vm_pgoff = pgoff;
2041 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002042 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 vma_link(mm, vma, prev, rb_link, rb_parent);
2044out:
2045 mm->total_vm += len >> PAGE_SHIFT;
2046 if (flags & VM_LOCKED) {
2047 mm->locked_vm += len >> PAGE_SHIFT;
2048 make_pages_present(addr, addr + len);
2049 }
2050 return addr;
2051}
2052
2053EXPORT_SYMBOL(do_brk);
2054
2055/* Release all mmaps. */
2056void exit_mmap(struct mm_struct *mm)
2057{
2058 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07002059 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002061 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002063 /* mm's last user has gone, and its about to be pulled down */
2064 arch_exit_mmap(mm);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002065 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002066
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002069 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002070 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002071 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002072 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07002074 free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002075 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002078 * Walk the list again, actually closing and freeing it,
2079 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002081 while (vma)
2082 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002083
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002084 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085}
2086
2087/* Insert vm structure into process list sorted by address
2088 * and into the inode's i_mmap tree. If vm_file is non-NULL
2089 * then i_mmap_lock is taken here.
2090 */
2091int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2092{
2093 struct vm_area_struct * __vma, * prev;
2094 struct rb_node ** rb_link, * rb_parent;
2095
2096 /*
2097 * The vm_pgoff of a purely anonymous vma should be irrelevant
2098 * until its first write fault, when page's anon_vma and index
2099 * are set. But now set the vm_pgoff it will almost certainly
2100 * end up with (unless mremap moves it elsewhere before that
2101 * first wfault), so /proc/pid/maps tells a consistent story.
2102 *
2103 * By setting it to reflect the virtual start address of the
2104 * vma, merges and splits can happen in a seamless way, just
2105 * using the existing file pgoff checks and manipulations.
2106 * Similarly in do_mmap_pgoff and in do_brk.
2107 */
2108 if (!vma->vm_file) {
2109 BUG_ON(vma->anon_vma);
2110 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2111 }
2112 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2113 if (__vma && __vma->vm_start < vma->vm_end)
2114 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002115 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002116 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002117 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 vma_link(mm, vma, prev, rb_link, rb_parent);
2119 return 0;
2120}
2121
2122/*
2123 * Copy the vma structure to a new location in the same mm,
2124 * prior to moving page table entries, to effect an mremap move.
2125 */
2126struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2127 unsigned long addr, unsigned long len, pgoff_t pgoff)
2128{
2129 struct vm_area_struct *vma = *vmap;
2130 unsigned long vma_start = vma->vm_start;
2131 struct mm_struct *mm = vma->vm_mm;
2132 struct vm_area_struct *new_vma, *prev;
2133 struct rb_node **rb_link, *rb_parent;
2134 struct mempolicy *pol;
2135
2136 /*
2137 * If anonymous vma has not yet been faulted, update new pgoff
2138 * to match new location, to increase its chance of merging.
2139 */
2140 if (!vma->vm_file && !vma->anon_vma)
2141 pgoff = addr >> PAGE_SHIFT;
2142
2143 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2144 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2145 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2146 if (new_vma) {
2147 /*
2148 * Source vma may have been merged into new_vma
2149 */
2150 if (vma_start >= new_vma->vm_start &&
2151 vma_start < new_vma->vm_end)
2152 *vmap = new_vma;
2153 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002154 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 if (new_vma) {
2156 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002157 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 if (IS_ERR(pol)) {
2159 kmem_cache_free(vm_area_cachep, new_vma);
2160 return NULL;
2161 }
2162 vma_set_policy(new_vma, pol);
2163 new_vma->vm_start = addr;
2164 new_vma->vm_end = addr + len;
2165 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002166 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002167 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002168 if (vma->vm_flags & VM_EXECUTABLE)
2169 added_exe_file_vma(mm);
2170 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 if (new_vma->vm_ops && new_vma->vm_ops->open)
2172 new_vma->vm_ops->open(new_vma);
2173 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2174 }
2175 }
2176 return new_vma;
2177}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002178
2179/*
2180 * Return true if the calling process may expand its vm space by the passed
2181 * number of pages
2182 */
2183int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2184{
2185 unsigned long cur = mm->total_vm; /* pages */
2186 unsigned long lim;
2187
2188 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2189
2190 if (cur + npages > lim)
2191 return 0;
2192 return 1;
2193}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002194
2195
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002196static int special_mapping_fault(struct vm_area_struct *vma,
2197 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002198{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002199 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002200 struct page **pages;
2201
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002202 /*
2203 * special mappings have no vm_file, and in that case, the mm
2204 * uses vm_pgoff internally. So we have to subtract it from here.
2205 * We are allowed to do this because we are the mm; do not copy
2206 * this code into drivers!
2207 */
2208 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002209
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002210 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2211 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002212
2213 if (*pages) {
2214 struct page *page = *pages;
2215 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002216 vmf->page = page;
2217 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002218 }
2219
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002220 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002221}
2222
2223/*
2224 * Having a close hook prevents vma merging regardless of flags.
2225 */
2226static void special_mapping_close(struct vm_area_struct *vma)
2227{
2228}
2229
2230static struct vm_operations_struct special_mapping_vmops = {
2231 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002232 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002233};
2234
2235/*
2236 * Called with mm->mmap_sem held for writing.
2237 * Insert a new vma covering the given region, with the given flags.
2238 * Its pages are supplied by the given array of struct page *.
2239 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2240 * The region past the last page supplied will always produce SIGBUS.
2241 * The array pointer and the pages it points to are assumed to stay alive
2242 * for as long as this mapping might exist.
2243 */
2244int install_special_mapping(struct mm_struct *mm,
2245 unsigned long addr, unsigned long len,
2246 unsigned long vm_flags, struct page **pages)
2247{
2248 struct vm_area_struct *vma;
2249
2250 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2251 if (unlikely(vma == NULL))
2252 return -ENOMEM;
2253
2254 vma->vm_mm = mm;
2255 vma->vm_start = addr;
2256 vma->vm_end = addr + len;
2257
Nick Piggin2f987352008-02-02 03:08:53 +01002258 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002259 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002260
2261 vma->vm_ops = &special_mapping_vmops;
2262 vma->vm_private_data = pages;
2263
2264 if (unlikely(insert_vm_struct(mm, vma))) {
2265 kmem_cache_free(vm_area_cachep, vma);
2266 return -ENOMEM;
2267 }
2268
2269 mm->total_vm += len >> PAGE_SHIFT;
2270
2271 return 0;
2272}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002273
2274static DEFINE_MUTEX(mm_all_locks_mutex);
2275
2276static void vm_lock_anon_vma(struct anon_vma *anon_vma)
2277{
2278 if (!test_bit(0, (unsigned long *) &anon_vma->head.next)) {
2279 /*
2280 * The LSB of head.next can't change from under us
2281 * because we hold the mm_all_locks_mutex.
2282 */
2283 spin_lock(&anon_vma->lock);
2284 /*
2285 * We can safely modify head.next after taking the
2286 * anon_vma->lock. If some other vma in this mm shares
2287 * the same anon_vma we won't take it again.
2288 *
2289 * No need of atomic instructions here, head.next
2290 * can't change from under us thanks to the
2291 * anon_vma->lock.
2292 */
2293 if (__test_and_set_bit(0, (unsigned long *)
2294 &anon_vma->head.next))
2295 BUG();
2296 }
2297}
2298
2299static void vm_lock_mapping(struct address_space *mapping)
2300{
2301 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2302 /*
2303 * AS_MM_ALL_LOCKS can't change from under us because
2304 * we hold the mm_all_locks_mutex.
2305 *
2306 * Operations on ->flags have to be atomic because
2307 * even if AS_MM_ALL_LOCKS is stable thanks to the
2308 * mm_all_locks_mutex, there may be other cpus
2309 * changing other bitflags in parallel to us.
2310 */
2311 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2312 BUG();
2313 spin_lock(&mapping->i_mmap_lock);
2314 }
2315}
2316
2317/*
2318 * This operation locks against the VM for all pte/vma/mm related
2319 * operations that could ever happen on a certain mm. This includes
2320 * vmtruncate, try_to_unmap, and all page faults.
2321 *
2322 * The caller must take the mmap_sem in write mode before calling
2323 * mm_take_all_locks(). The caller isn't allowed to release the
2324 * mmap_sem until mm_drop_all_locks() returns.
2325 *
2326 * mmap_sem in write mode is required in order to block all operations
2327 * that could modify pagetables and free pages without need of
2328 * altering the vma layout (for example populate_range() with
2329 * nonlinear vmas). It's also needed in write mode to avoid new
2330 * anon_vmas to be associated with existing vmas.
2331 *
2332 * A single task can't take more than one mm_take_all_locks() in a row
2333 * or it would deadlock.
2334 *
2335 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2336 * mapping->flags avoid to take the same lock twice, if more than one
2337 * vma in this mm is backed by the same anon_vma or address_space.
2338 *
2339 * We can take all the locks in random order because the VM code
2340 * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never
2341 * takes more than one of them in a row. Secondly we're protected
2342 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2343 *
2344 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2345 * that may have to take thousand of locks.
2346 *
2347 * mm_take_all_locks() can fail if it's interrupted by signals.
2348 */
2349int mm_take_all_locks(struct mm_struct *mm)
2350{
2351 struct vm_area_struct *vma;
2352 int ret = -EINTR;
2353
2354 BUG_ON(down_read_trylock(&mm->mmap_sem));
2355
2356 mutex_lock(&mm_all_locks_mutex);
2357
2358 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2359 if (signal_pending(current))
2360 goto out_unlock;
2361 if (vma->anon_vma)
2362 vm_lock_anon_vma(vma->anon_vma);
2363 if (vma->vm_file && vma->vm_file->f_mapping)
2364 vm_lock_mapping(vma->vm_file->f_mapping);
2365 }
2366 ret = 0;
2367
2368out_unlock:
2369 if (ret)
2370 mm_drop_all_locks(mm);
2371
2372 return ret;
2373}
2374
2375static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2376{
2377 if (test_bit(0, (unsigned long *) &anon_vma->head.next)) {
2378 /*
2379 * The LSB of head.next can't change to 0 from under
2380 * us because we hold the mm_all_locks_mutex.
2381 *
2382 * We must however clear the bitflag before unlocking
2383 * the vma so the users using the anon_vma->head will
2384 * never see our bitflag.
2385 *
2386 * No need of atomic instructions here, head.next
2387 * can't change from under us until we release the
2388 * anon_vma->lock.
2389 */
2390 if (!__test_and_clear_bit(0, (unsigned long *)
2391 &anon_vma->head.next))
2392 BUG();
2393 spin_unlock(&anon_vma->lock);
2394 }
2395}
2396
2397static void vm_unlock_mapping(struct address_space *mapping)
2398{
2399 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2400 /*
2401 * AS_MM_ALL_LOCKS can't change to 0 from under us
2402 * because we hold the mm_all_locks_mutex.
2403 */
2404 spin_unlock(&mapping->i_mmap_lock);
2405 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2406 &mapping->flags))
2407 BUG();
2408 }
2409}
2410
2411/*
2412 * The mmap_sem cannot be released by the caller until
2413 * mm_drop_all_locks() returns.
2414 */
2415void mm_drop_all_locks(struct mm_struct *mm)
2416{
2417 struct vm_area_struct *vma;
2418
2419 BUG_ON(down_read_trylock(&mm->mmap_sem));
2420 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2421
2422 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2423 if (vma->anon_vma)
2424 vm_unlock_anon_vma(vma->anon_vma);
2425 if (vma->vm_file && vma->vm_file->f_mapping)
2426 vm_unlock_mapping(vma->vm_file->f_mapping);
2427 }
2428
2429 mutex_unlock(&mm_all_locks_mutex);
2430}