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fix a struct file leak in do_mmap_pgoff()
[net-next-2.6.git] / mm / mmap.c
CommitLineData
1da177e4
LT
1/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
046c6884 6 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
1da177e4
LT
7 */
8
9#include <linux/slab.h>
4af3c9cc 10#include <linux/backing-dev.h>
1da177e4
LT
11#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
c59ede7b 17#include <linux/capability.h>
1da177e4
LT
18#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
cddb8a5c 29#include <linux/mmu_notifier.h>
cdd6c482 30#include <linux/perf_event.h>
1da177e4
LT
31
32#include <asm/uaccess.h>
33#include <asm/cacheflush.h>
34#include <asm/tlb.h>
d6dd61c8 35#include <asm/mmu_context.h>
1da177e4 36
42b77728
JB
37#include "internal.h"
38
3a459756
KK
39#ifndef arch_mmap_check
40#define arch_mmap_check(addr, len, flags) (0)
41#endif
42
08e7d9b5
MS
43#ifndef arch_rebalance_pgtables
44#define arch_rebalance_pgtables(addr, len) (addr)
45#endif
46
e0da382c
HD
47static void unmap_region(struct mm_struct *mm,
48 struct vm_area_struct *vma, struct vm_area_struct *prev,
49 unsigned long start, unsigned long end);
50
1da177e4
LT
51/*
52 * WARNING: the debugging will use recursive algorithms so never enable this
53 * unless you know what you are doing.
54 */
55#undef DEBUG_MM_RB
56
57/* description of effects of mapping type and prot in current implementation.
58 * this is due to the limited x86 page protection hardware. The expected
59 * behavior is in parens:
60 *
61 * map_type prot
62 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
63 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
64 * w: (no) no w: (no) no w: (yes) yes w: (no) no
65 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
66 *
67 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
68 * w: (no) no w: (no) no w: (copy) copy w: (no) no
69 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
70 *
71 */
72pgprot_t protection_map[16] = {
73 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
74 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
75};
76
804af2cf
HD
77pgprot_t vm_get_page_prot(unsigned long vm_flags)
78{
b845f313
DK
79 return __pgprot(pgprot_val(protection_map[vm_flags &
80 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
81 pgprot_val(arch_vm_get_page_prot(vm_flags)));
804af2cf
HD
82}
83EXPORT_SYMBOL(vm_get_page_prot);
84
1da177e4
LT
85int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
86int sysctl_overcommit_ratio = 50; /* default is 50% */
c3d8c141 87int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
00a62ce9 88struct percpu_counter vm_committed_as;
1da177e4
LT
89
90/*
91 * Check that a process has enough memory to allocate a new virtual
92 * mapping. 0 means there is enough memory for the allocation to
93 * succeed and -ENOMEM implies there is not.
94 *
95 * We currently support three overcommit policies, which are set via the
96 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
97 *
98 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
99 * Additional code 2002 Jul 20 by Robert Love.
100 *
101 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
102 *
103 * Note this is a helper function intended to be used by LSMs which
104 * wish to use this logic.
105 */
34b4e4aa 106int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1da177e4
LT
107{
108 unsigned long free, allowed;
109
110 vm_acct_memory(pages);
111
112 /*
113 * Sometimes we want to use more memory than we have
114 */
115 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
116 return 0;
117
118 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
119 unsigned long n;
120
347ce434 121 free = global_page_state(NR_FILE_PAGES);
1da177e4
LT
122 free += nr_swap_pages;
123
124 /*
125 * Any slabs which are created with the
126 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
127 * which are reclaimable, under pressure. The dentry
128 * cache and most inode caches should fall into this
129 */
972d1a7b 130 free += global_page_state(NR_SLAB_RECLAIMABLE);
1da177e4
LT
131
132 /*
133 * Leave the last 3% for root
134 */
135 if (!cap_sys_admin)
136 free -= free / 32;
137
138 if (free > pages)
139 return 0;
140
141 /*
142 * nr_free_pages() is very expensive on large systems,
143 * only call if we're about to fail.
144 */
145 n = nr_free_pages();
6d9f7839
HA
146
147 /*
148 * Leave reserved pages. The pages are not for anonymous pages.
149 */
150 if (n <= totalreserve_pages)
151 goto error;
152 else
153 n -= totalreserve_pages;
154
155 /*
156 * Leave the last 3% for root
157 */
1da177e4
LT
158 if (!cap_sys_admin)
159 n -= n / 32;
160 free += n;
161
162 if (free > pages)
163 return 0;
6d9f7839
HA
164
165 goto error;
1da177e4
LT
166 }
167
168 allowed = (totalram_pages - hugetlb_total_pages())
169 * sysctl_overcommit_ratio / 100;
170 /*
171 * Leave the last 3% for root
172 */
173 if (!cap_sys_admin)
174 allowed -= allowed / 32;
175 allowed += total_swap_pages;
176
177 /* Don't let a single process grow too big:
178 leave 3% of the size of this process for other processes */
731572d3
AC
179 if (mm)
180 allowed -= mm->total_vm / 32;
1da177e4 181
00a62ce9 182 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1da177e4 183 return 0;
6d9f7839 184error:
1da177e4
LT
185 vm_unacct_memory(pages);
186
187 return -ENOMEM;
188}
189
1da177e4
LT
190/*
191 * Requires inode->i_mapping->i_mmap_lock
192 */
193static void __remove_shared_vm_struct(struct vm_area_struct *vma,
194 struct file *file, struct address_space *mapping)
195{
196 if (vma->vm_flags & VM_DENYWRITE)
d3ac7f89 197 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
1da177e4
LT
198 if (vma->vm_flags & VM_SHARED)
199 mapping->i_mmap_writable--;
200
201 flush_dcache_mmap_lock(mapping);
202 if (unlikely(vma->vm_flags & VM_NONLINEAR))
203 list_del_init(&vma->shared.vm_set.list);
204 else
205 vma_prio_tree_remove(vma, &mapping->i_mmap);
206 flush_dcache_mmap_unlock(mapping);
207}
208
209/*
a8fb5618
HD
210 * Unlink a file-based vm structure from its prio_tree, to hide
211 * vma from rmap and vmtruncate before freeing its page tables.
1da177e4 212 */
a8fb5618 213void unlink_file_vma(struct vm_area_struct *vma)
1da177e4
LT
214{
215 struct file *file = vma->vm_file;
216
1da177e4
LT
217 if (file) {
218 struct address_space *mapping = file->f_mapping;
219 spin_lock(&mapping->i_mmap_lock);
220 __remove_shared_vm_struct(vma, file, mapping);
221 spin_unlock(&mapping->i_mmap_lock);
222 }
a8fb5618
HD
223}
224
225/*
226 * Close a vm structure and free it, returning the next.
227 */
228static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
229{
230 struct vm_area_struct *next = vma->vm_next;
231
a8fb5618 232 might_sleep();
1da177e4
LT
233 if (vma->vm_ops && vma->vm_ops->close)
234 vma->vm_ops->close(vma);
925d1c40 235 if (vma->vm_file) {
a8fb5618 236 fput(vma->vm_file);
925d1c40
MH
237 if (vma->vm_flags & VM_EXECUTABLE)
238 removed_exe_file_vma(vma->vm_mm);
239 }
f0be3d32 240 mpol_put(vma_policy(vma));
1da177e4 241 kmem_cache_free(vm_area_cachep, vma);
a8fb5618 242 return next;
1da177e4
LT
243}
244
6a6160a7 245SYSCALL_DEFINE1(brk, unsigned long, brk)
1da177e4
LT
246{
247 unsigned long rlim, retval;
248 unsigned long newbrk, oldbrk;
249 struct mm_struct *mm = current->mm;
a5b4592c 250 unsigned long min_brk;
1da177e4
LT
251
252 down_write(&mm->mmap_sem);
253
a5b4592c
JK
254#ifdef CONFIG_COMPAT_BRK
255 min_brk = mm->end_code;
256#else
257 min_brk = mm->start_brk;
258#endif
259 if (brk < min_brk)
1da177e4 260 goto out;
1e624196
RG
261
262 /*
263 * Check against rlimit here. If this check is done later after the test
264 * of oldbrk with newbrk then it can escape the test and let the data
265 * segment grow beyond its set limit the in case where the limit is
266 * not page aligned -Ram Gupta
267 */
268 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
c1d171a0
JK
269 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
270 (mm->end_data - mm->start_data) > rlim)
1e624196
RG
271 goto out;
272
1da177e4
LT
273 newbrk = PAGE_ALIGN(brk);
274 oldbrk = PAGE_ALIGN(mm->brk);
275 if (oldbrk == newbrk)
276 goto set_brk;
277
278 /* Always allow shrinking brk. */
279 if (brk <= mm->brk) {
280 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
281 goto set_brk;
282 goto out;
283 }
284
1da177e4
LT
285 /* Check against existing mmap mappings. */
286 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
287 goto out;
288
289 /* Ok, looks good - let it rip. */
290 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
291 goto out;
292set_brk:
293 mm->brk = brk;
294out:
295 retval = mm->brk;
296 up_write(&mm->mmap_sem);
297 return retval;
298}
299
300#ifdef DEBUG_MM_RB
301static int browse_rb(struct rb_root *root)
302{
303 int i = 0, j;
304 struct rb_node *nd, *pn = NULL;
305 unsigned long prev = 0, pend = 0;
306
307 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
308 struct vm_area_struct *vma;
309 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
310 if (vma->vm_start < prev)
311 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
312 if (vma->vm_start < pend)
313 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
314 if (vma->vm_start > vma->vm_end)
315 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
316 i++;
317 pn = nd;
d1af65d1
DM
318 prev = vma->vm_start;
319 pend = vma->vm_end;
1da177e4
LT
320 }
321 j = 0;
322 for (nd = pn; nd; nd = rb_prev(nd)) {
323 j++;
324 }
325 if (i != j)
326 printk("backwards %d, forwards %d\n", j, i), i = 0;
327 return i;
328}
329
330void validate_mm(struct mm_struct *mm)
331{
332 int bug = 0;
333 int i = 0;
334 struct vm_area_struct *tmp = mm->mmap;
335 while (tmp) {
336 tmp = tmp->vm_next;
337 i++;
338 }
339 if (i != mm->map_count)
340 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
341 i = browse_rb(&mm->mm_rb);
342 if (i != mm->map_count)
343 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
46a350ef 344 BUG_ON(bug);
1da177e4
LT
345}
346#else
347#define validate_mm(mm) do { } while (0)
348#endif
349
350static struct vm_area_struct *
351find_vma_prepare(struct mm_struct *mm, unsigned long addr,
352 struct vm_area_struct **pprev, struct rb_node ***rb_link,
353 struct rb_node ** rb_parent)
354{
355 struct vm_area_struct * vma;
356 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
357
358 __rb_link = &mm->mm_rb.rb_node;
359 rb_prev = __rb_parent = NULL;
360 vma = NULL;
361
362 while (*__rb_link) {
363 struct vm_area_struct *vma_tmp;
364
365 __rb_parent = *__rb_link;
366 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
367
368 if (vma_tmp->vm_end > addr) {
369 vma = vma_tmp;
370 if (vma_tmp->vm_start <= addr)
dfe195fb 371 break;
1da177e4
LT
372 __rb_link = &__rb_parent->rb_left;
373 } else {
374 rb_prev = __rb_parent;
375 __rb_link = &__rb_parent->rb_right;
376 }
377 }
378
379 *pprev = NULL;
380 if (rb_prev)
381 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
382 *rb_link = __rb_link;
383 *rb_parent = __rb_parent;
384 return vma;
385}
386
387static inline void
388__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
389 struct vm_area_struct *prev, struct rb_node *rb_parent)
390{
391 if (prev) {
392 vma->vm_next = prev->vm_next;
393 prev->vm_next = vma;
394 } else {
395 mm->mmap = vma;
396 if (rb_parent)
397 vma->vm_next = rb_entry(rb_parent,
398 struct vm_area_struct, vm_rb);
399 else
400 vma->vm_next = NULL;
401 }
402}
403
404void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
405 struct rb_node **rb_link, struct rb_node *rb_parent)
406{
407 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
408 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
409}
410
cb8f488c 411static void __vma_link_file(struct vm_area_struct *vma)
1da177e4 412{
48aae425 413 struct file *file;
1da177e4
LT
414
415 file = vma->vm_file;
416 if (file) {
417 struct address_space *mapping = file->f_mapping;
418
419 if (vma->vm_flags & VM_DENYWRITE)
d3ac7f89 420 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
1da177e4
LT
421 if (vma->vm_flags & VM_SHARED)
422 mapping->i_mmap_writable++;
423
424 flush_dcache_mmap_lock(mapping);
425 if (unlikely(vma->vm_flags & VM_NONLINEAR))
426 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
427 else
428 vma_prio_tree_insert(vma, &mapping->i_mmap);
429 flush_dcache_mmap_unlock(mapping);
430 }
431}
432
433static void
434__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
435 struct vm_area_struct *prev, struct rb_node **rb_link,
436 struct rb_node *rb_parent)
437{
438 __vma_link_list(mm, vma, prev, rb_parent);
439 __vma_link_rb(mm, vma, rb_link, rb_parent);
440 __anon_vma_link(vma);
441}
442
443static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
444 struct vm_area_struct *prev, struct rb_node **rb_link,
445 struct rb_node *rb_parent)
446{
447 struct address_space *mapping = NULL;
448
449 if (vma->vm_file)
450 mapping = vma->vm_file->f_mapping;
451
452 if (mapping) {
453 spin_lock(&mapping->i_mmap_lock);
454 vma->vm_truncate_count = mapping->truncate_count;
455 }
456 anon_vma_lock(vma);
457
458 __vma_link(mm, vma, prev, rb_link, rb_parent);
459 __vma_link_file(vma);
460
461 anon_vma_unlock(vma);
462 if (mapping)
463 spin_unlock(&mapping->i_mmap_lock);
464
465 mm->map_count++;
466 validate_mm(mm);
467}
468
469/*
470 * Helper for vma_adjust in the split_vma insert case:
471 * insert vm structure into list and rbtree and anon_vma,
472 * but it has already been inserted into prio_tree earlier.
473 */
48aae425 474static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
1da177e4 475{
48aae425
Z
476 struct vm_area_struct *__vma, *prev;
477 struct rb_node **rb_link, *rb_parent;
1da177e4
LT
478
479 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
46a350ef 480 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
1da177e4
LT
481 __vma_link(mm, vma, prev, rb_link, rb_parent);
482 mm->map_count++;
483}
484
485static inline void
486__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
487 struct vm_area_struct *prev)
488{
489 prev->vm_next = vma->vm_next;
490 rb_erase(&vma->vm_rb, &mm->mm_rb);
491 if (mm->mmap_cache == vma)
492 mm->mmap_cache = prev;
493}
494
495/*
496 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
497 * is already present in an i_mmap tree without adjusting the tree.
498 * The following helper function should be used when such adjustments
499 * are necessary. The "insert" vma (if any) is to be inserted
500 * before we drop the necessary locks.
501 */
502void vma_adjust(struct vm_area_struct *vma, unsigned long start,
503 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
504{
505 struct mm_struct *mm = vma->vm_mm;
506 struct vm_area_struct *next = vma->vm_next;
507 struct vm_area_struct *importer = NULL;
508 struct address_space *mapping = NULL;
509 struct prio_tree_root *root = NULL;
510 struct file *file = vma->vm_file;
511 struct anon_vma *anon_vma = NULL;
512 long adjust_next = 0;
513 int remove_next = 0;
514
515 if (next && !insert) {
516 if (end >= next->vm_end) {
517 /*
518 * vma expands, overlapping all the next, and
519 * perhaps the one after too (mprotect case 6).
520 */
521again: remove_next = 1 + (end > next->vm_end);
522 end = next->vm_end;
523 anon_vma = next->anon_vma;
524 importer = vma;
525 } else if (end > next->vm_start) {
526 /*
527 * vma expands, overlapping part of the next:
528 * mprotect case 5 shifting the boundary up.
529 */
530 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
531 anon_vma = next->anon_vma;
532 importer = vma;
533 } else if (end < vma->vm_end) {
534 /*
535 * vma shrinks, and !insert tells it's not
536 * split_vma inserting another: so it must be
537 * mprotect case 4 shifting the boundary down.
538 */
539 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
540 anon_vma = next->anon_vma;
541 importer = next;
542 }
543 }
544
545 if (file) {
546 mapping = file->f_mapping;
547 if (!(vma->vm_flags & VM_NONLINEAR))
548 root = &mapping->i_mmap;
549 spin_lock(&mapping->i_mmap_lock);
550 if (importer &&
551 vma->vm_truncate_count != next->vm_truncate_count) {
552 /*
553 * unmap_mapping_range might be in progress:
554 * ensure that the expanding vma is rescanned.
555 */
556 importer->vm_truncate_count = 0;
557 }
558 if (insert) {
559 insert->vm_truncate_count = vma->vm_truncate_count;
560 /*
561 * Put into prio_tree now, so instantiated pages
562 * are visible to arm/parisc __flush_dcache_page
563 * throughout; but we cannot insert into address
564 * space until vma start or end is updated.
565 */
566 __vma_link_file(insert);
567 }
568 }
569
570 /*
571 * When changing only vma->vm_end, we don't really need
252c5f94 572 * anon_vma lock.
1da177e4 573 */
252c5f94 574 if (vma->anon_vma && (insert || importer || start != vma->vm_start))
1da177e4
LT
575 anon_vma = vma->anon_vma;
576 if (anon_vma) {
577 spin_lock(&anon_vma->lock);
578 /*
579 * Easily overlooked: when mprotect shifts the boundary,
580 * make sure the expanding vma has anon_vma set if the
581 * shrinking vma had, to cover any anon pages imported.
582 */
583 if (importer && !importer->anon_vma) {
584 importer->anon_vma = anon_vma;
585 __anon_vma_link(importer);
586 }
587 }
588
589 if (root) {
590 flush_dcache_mmap_lock(mapping);
591 vma_prio_tree_remove(vma, root);
592 if (adjust_next)
593 vma_prio_tree_remove(next, root);
594 }
595
596 vma->vm_start = start;
597 vma->vm_end = end;
598 vma->vm_pgoff = pgoff;
599 if (adjust_next) {
600 next->vm_start += adjust_next << PAGE_SHIFT;
601 next->vm_pgoff += adjust_next;
602 }
603
604 if (root) {
605 if (adjust_next)
606 vma_prio_tree_insert(next, root);
607 vma_prio_tree_insert(vma, root);
608 flush_dcache_mmap_unlock(mapping);
609 }
610
611 if (remove_next) {
612 /*
613 * vma_merge has merged next into vma, and needs
614 * us to remove next before dropping the locks.
615 */
616 __vma_unlink(mm, next, vma);
617 if (file)
618 __remove_shared_vm_struct(next, file, mapping);
619 if (next->anon_vma)
620 __anon_vma_merge(vma, next);
621 } else if (insert) {
622 /*
623 * split_vma has split insert from vma, and needs
624 * us to insert it before dropping the locks
625 * (it may either follow vma or precede it).
626 */
627 __insert_vm_struct(mm, insert);
628 }
629
630 if (anon_vma)
631 spin_unlock(&anon_vma->lock);
632 if (mapping)
633 spin_unlock(&mapping->i_mmap_lock);
634
635 if (remove_next) {
925d1c40 636 if (file) {
1da177e4 637 fput(file);
925d1c40
MH
638 if (next->vm_flags & VM_EXECUTABLE)
639 removed_exe_file_vma(mm);
640 }
1da177e4 641 mm->map_count--;
f0be3d32 642 mpol_put(vma_policy(next));
1da177e4
LT
643 kmem_cache_free(vm_area_cachep, next);
644 /*
645 * In mprotect's case 6 (see comments on vma_merge),
646 * we must remove another next too. It would clutter
647 * up the code too much to do both in one go.
648 */
649 if (remove_next == 2) {
650 next = vma->vm_next;
651 goto again;
652 }
653 }
654
655 validate_mm(mm);
656}
657
658/*
659 * If the vma has a ->close operation then the driver probably needs to release
660 * per-vma resources, so we don't attempt to merge those.
661 */
1da177e4
LT
662static inline int is_mergeable_vma(struct vm_area_struct *vma,
663 struct file *file, unsigned long vm_flags)
664{
8314c4f2
HD
665 /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
666 if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
1da177e4
LT
667 return 0;
668 if (vma->vm_file != file)
669 return 0;
670 if (vma->vm_ops && vma->vm_ops->close)
671 return 0;
672 return 1;
673}
674
675static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
676 struct anon_vma *anon_vma2)
677{
678 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
679}
680
681/*
682 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
683 * in front of (at a lower virtual address and file offset than) the vma.
684 *
685 * We cannot merge two vmas if they have differently assigned (non-NULL)
686 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
687 *
688 * We don't check here for the merged mmap wrapping around the end of pagecache
689 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
690 * wrap, nor mmaps which cover the final page at index -1UL.
691 */
692static int
693can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
694 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
695{
696 if (is_mergeable_vma(vma, file, vm_flags) &&
697 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
698 if (vma->vm_pgoff == vm_pgoff)
699 return 1;
700 }
701 return 0;
702}
703
704/*
705 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
706 * beyond (at a higher virtual address and file offset than) the vma.
707 *
708 * We cannot merge two vmas if they have differently assigned (non-NULL)
709 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
710 */
711static int
712can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
713 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
714{
715 if (is_mergeable_vma(vma, file, vm_flags) &&
716 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
717 pgoff_t vm_pglen;
718 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
719 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
720 return 1;
721 }
722 return 0;
723}
724
725/*
726 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
727 * whether that can be merged with its predecessor or its successor.
728 * Or both (it neatly fills a hole).
729 *
730 * In most cases - when called for mmap, brk or mremap - [addr,end) is
731 * certain not to be mapped by the time vma_merge is called; but when
732 * called for mprotect, it is certain to be already mapped (either at
733 * an offset within prev, or at the start of next), and the flags of
734 * this area are about to be changed to vm_flags - and the no-change
735 * case has already been eliminated.
736 *
737 * The following mprotect cases have to be considered, where AAAA is
738 * the area passed down from mprotect_fixup, never extending beyond one
739 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
740 *
741 * AAAA AAAA AAAA AAAA
742 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
743 * cannot merge might become might become might become
744 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
745 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
746 * mremap move: PPPPNNNNNNNN 8
747 * AAAA
748 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
749 * might become case 1 below case 2 below case 3 below
750 *
751 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
752 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
753 */
754struct vm_area_struct *vma_merge(struct mm_struct *mm,
755 struct vm_area_struct *prev, unsigned long addr,
756 unsigned long end, unsigned long vm_flags,
757 struct anon_vma *anon_vma, struct file *file,
758 pgoff_t pgoff, struct mempolicy *policy)
759{
760 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
761 struct vm_area_struct *area, *next;
762
763 /*
764 * We later require that vma->vm_flags == vm_flags,
765 * so this tests vma->vm_flags & VM_SPECIAL, too.
766 */
767 if (vm_flags & VM_SPECIAL)
768 return NULL;
769
770 if (prev)
771 next = prev->vm_next;
772 else
773 next = mm->mmap;
774 area = next;
775 if (next && next->vm_end == end) /* cases 6, 7, 8 */
776 next = next->vm_next;
777
778 /*
779 * Can it merge with the predecessor?
780 */
781 if (prev && prev->vm_end == addr &&
782 mpol_equal(vma_policy(prev), policy) &&
783 can_vma_merge_after(prev, vm_flags,
784 anon_vma, file, pgoff)) {
785 /*
786 * OK, it can. Can we now merge in the successor as well?
787 */
788 if (next && end == next->vm_start &&
789 mpol_equal(policy, vma_policy(next)) &&
790 can_vma_merge_before(next, vm_flags,
791 anon_vma, file, pgoff+pglen) &&
792 is_mergeable_anon_vma(prev->anon_vma,
793 next->anon_vma)) {
794 /* cases 1, 6 */
795 vma_adjust(prev, prev->vm_start,
796 next->vm_end, prev->vm_pgoff, NULL);
797 } else /* cases 2, 5, 7 */
798 vma_adjust(prev, prev->vm_start,
799 end, prev->vm_pgoff, NULL);
800 return prev;
801 }
802
803 /*
804 * Can this new request be merged in front of next?
805 */
806 if (next && end == next->vm_start &&
807 mpol_equal(policy, vma_policy(next)) &&
808 can_vma_merge_before(next, vm_flags,
809 anon_vma, file, pgoff+pglen)) {
810 if (prev && addr < prev->vm_end) /* case 4 */
811 vma_adjust(prev, prev->vm_start,
812 addr, prev->vm_pgoff, NULL);
813 else /* cases 3, 8 */
814 vma_adjust(area, addr, next->vm_end,
815 next->vm_pgoff - pglen, NULL);
816 return area;
817 }
818
819 return NULL;
820}
821
822/*
823 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
824 * neighbouring vmas for a suitable anon_vma, before it goes off
825 * to allocate a new anon_vma. It checks because a repetitive
826 * sequence of mprotects and faults may otherwise lead to distinct
827 * anon_vmas being allocated, preventing vma merge in subsequent
828 * mprotect.
829 */
830struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
831{
832 struct vm_area_struct *near;
833 unsigned long vm_flags;
834
835 near = vma->vm_next;
836 if (!near)
837 goto try_prev;
838
839 /*
840 * Since only mprotect tries to remerge vmas, match flags
841 * which might be mprotected into each other later on.
842 * Neither mlock nor madvise tries to remerge at present,
843 * so leave their flags as obstructing a merge.
844 */
845 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
846 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
847
848 if (near->anon_vma && vma->vm_end == near->vm_start &&
849 mpol_equal(vma_policy(vma), vma_policy(near)) &&
850 can_vma_merge_before(near, vm_flags,
851 NULL, vma->vm_file, vma->vm_pgoff +
852 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
853 return near->anon_vma;
854try_prev:
855 /*
856 * It is potentially slow to have to call find_vma_prev here.
857 * But it's only on the first write fault on the vma, not
858 * every time, and we could devise a way to avoid it later
859 * (e.g. stash info in next's anon_vma_node when assigning
860 * an anon_vma, or when trying vma_merge). Another time.
861 */
46a350ef 862 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
1da177e4
LT
863 if (!near)
864 goto none;
865
866 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
867 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
868
869 if (near->anon_vma && near->vm_end == vma->vm_start &&
870 mpol_equal(vma_policy(near), vma_policy(vma)) &&
871 can_vma_merge_after(near, vm_flags,
872 NULL, vma->vm_file, vma->vm_pgoff))
873 return near->anon_vma;
874none:
875 /*
876 * There's no absolute need to look only at touching neighbours:
877 * we could search further afield for "compatible" anon_vmas.
878 * But it would probably just be a waste of time searching,
879 * or lead to too many vmas hanging off the same anon_vma.
880 * We're trying to allow mprotect remerging later on,
881 * not trying to minimize memory used for anon_vmas.
882 */
883 return NULL;
884}
885
886#ifdef CONFIG_PROC_FS
ab50b8ed 887void vm_stat_account(struct mm_struct *mm, unsigned long flags,
1da177e4
LT
888 struct file *file, long pages)
889{
890 const unsigned long stack_flags
891 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
892
1da177e4
LT
893 if (file) {
894 mm->shared_vm += pages;
895 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
896 mm->exec_vm += pages;
897 } else if (flags & stack_flags)
898 mm->stack_vm += pages;
899 if (flags & (VM_RESERVED|VM_IO))
900 mm->reserved_vm += pages;
901}
902#endif /* CONFIG_PROC_FS */
903
904/*
27f5de79 905 * The caller must hold down_write(&current->mm->mmap_sem).
1da177e4
LT
906 */
907
48aae425 908unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
1da177e4
LT
909 unsigned long len, unsigned long prot,
910 unsigned long flags, unsigned long pgoff)
911{
912 struct mm_struct * mm = current->mm;
1da177e4
LT
913 struct inode *inode;
914 unsigned int vm_flags;
1da177e4 915 int error;
0165ab44 916 unsigned long reqprot = prot;
1da177e4 917
1da177e4
LT
918 /*
919 * Does the application expect PROT_READ to imply PROT_EXEC?
920 *
921 * (the exception is when the underlying filesystem is noexec
922 * mounted, in which case we dont add PROT_EXEC.)
923 */
924 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
d3ac7f89 925 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
1da177e4
LT
926 prot |= PROT_EXEC;
927
928 if (!len)
929 return -EINVAL;
930
7cd94146
EP
931 if (!(flags & MAP_FIXED))
932 addr = round_hint_to_min(addr);
933
3a459756
KK
934 error = arch_mmap_check(addr, len, flags);
935 if (error)
936 return error;
937
1da177e4
LT
938 /* Careful about overflows.. */
939 len = PAGE_ALIGN(len);
940 if (!len || len > TASK_SIZE)
941 return -ENOMEM;
942
943 /* offset overflow? */
944 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
945 return -EOVERFLOW;
946
947 /* Too many mappings? */
948 if (mm->map_count > sysctl_max_map_count)
949 return -ENOMEM;
950
951 /* Obtain the address to map to. we verify (or select) it and ensure
952 * that it represents a valid section of the address space.
953 */
954 addr = get_unmapped_area(file, addr, len, pgoff, flags);
955 if (addr & ~PAGE_MASK)
956 return addr;
957
958 /* Do simple checking here so the lower-level routines won't have
959 * to. we assume access permissions have been handled by the open
960 * of the memory object, so we don't do any here.
961 */
962 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
963 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
964
cdf7b341 965 if (flags & MAP_LOCKED)
1da177e4
LT
966 if (!can_do_mlock())
967 return -EPERM;
ba470de4 968
1da177e4
LT
969 /* mlock MCL_FUTURE? */
970 if (vm_flags & VM_LOCKED) {
971 unsigned long locked, lock_limit;
93ea1d0a
CW
972 locked = len >> PAGE_SHIFT;
973 locked += mm->locked_vm;
1da177e4 974 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
93ea1d0a 975 lock_limit >>= PAGE_SHIFT;
1da177e4
LT
976 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
977 return -EAGAIN;
978 }
979
d3ac7f89 980 inode = file ? file->f_path.dentry->d_inode : NULL;
1da177e4
LT
981
982 if (file) {
983 switch (flags & MAP_TYPE) {
984 case MAP_SHARED:
985 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
986 return -EACCES;
987
988 /*
989 * Make sure we don't allow writing to an append-only
990 * file..
991 */
992 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
993 return -EACCES;
994
995 /*
996 * Make sure there are no mandatory locks on the file.
997 */
998 if (locks_verify_locked(inode))
999 return -EAGAIN;
1000
1001 vm_flags |= VM_SHARED | VM_MAYSHARE;
1002 if (!(file->f_mode & FMODE_WRITE))
1003 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1004
1005 /* fall through */
1006 case MAP_PRIVATE:
1007 if (!(file->f_mode & FMODE_READ))
1008 return -EACCES;
d3ac7f89 1009 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
80c5606c
LT
1010 if (vm_flags & VM_EXEC)
1011 return -EPERM;
1012 vm_flags &= ~VM_MAYEXEC;
1013 }
80c5606c
LT
1014
1015 if (!file->f_op || !file->f_op->mmap)
1016 return -ENODEV;
1da177e4
LT
1017 break;
1018
1019 default:
1020 return -EINVAL;
1021 }
1022 } else {
1023 switch (flags & MAP_TYPE) {
1024 case MAP_SHARED:
ce363942
TH
1025 /*
1026 * Ignore pgoff.
1027 */
1028 pgoff = 0;
1da177e4
LT
1029 vm_flags |= VM_SHARED | VM_MAYSHARE;
1030 break;
1031 case MAP_PRIVATE:
1032 /*
1033 * Set pgoff according to addr for anon_vma.
1034 */
1035 pgoff = addr >> PAGE_SHIFT;
1036 break;
1037 default:
1038 return -EINVAL;
1039 }
1040 }
1041
ed032189 1042 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
1da177e4
LT
1043 if (error)
1044 return error;
ed032189 1045
5a6fe125 1046 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
0165ab44
MS
1047}
1048EXPORT_SYMBOL(do_mmap_pgoff);
1049
4e950f6f
AD
1050/*
1051 * Some shared mappigns will want the pages marked read-only
1052 * to track write events. If so, we'll downgrade vm_page_prot
1053 * to the private version (using protection_map[] without the
1054 * VM_SHARED bit).
1055 */
1056int vma_wants_writenotify(struct vm_area_struct *vma)
1057{
1058 unsigned int vm_flags = vma->vm_flags;
1059
1060 /* If it was private or non-writable, the write bit is already clear */
1061 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1062 return 0;
1063
1064 /* The backer wishes to know when pages are first written to? */
1065 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1066 return 1;
1067
1068 /* The open routine did something to the protections already? */
1069 if (pgprot_val(vma->vm_page_prot) !=
3ed75eb8 1070 pgprot_val(vm_get_page_prot(vm_flags)))
4e950f6f
AD
1071 return 0;
1072
1073 /* Specialty mapping? */
1074 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1075 return 0;
1076
1077 /* Can the mapping track the dirty pages? */
1078 return vma->vm_file && vma->vm_file->f_mapping &&
1079 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1080}
1081
fc8744ad
LT
1082/*
1083 * We account for memory if it's a private writeable mapping,
5a6fe125 1084 * not hugepages and VM_NORESERVE wasn't set.
fc8744ad 1085 */
5a6fe125 1086static inline int accountable_mapping(struct file *file, unsigned int vm_flags)
fc8744ad 1087{
5a6fe125
MG
1088 /*
1089 * hugetlb has its own accounting separate from the core VM
1090 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1091 */
1092 if (file && is_file_hugepages(file))
1093 return 0;
1094
fc8744ad
LT
1095 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1096}
1097
0165ab44
MS
1098unsigned long mmap_region(struct file *file, unsigned long addr,
1099 unsigned long len, unsigned long flags,
5a6fe125 1100 unsigned int vm_flags, unsigned long pgoff)
0165ab44
MS
1101{
1102 struct mm_struct *mm = current->mm;
1103 struct vm_area_struct *vma, *prev;
1104 int correct_wcount = 0;
1105 int error;
1106 struct rb_node **rb_link, *rb_parent;
1107 unsigned long charged = 0;
1108 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1109
1da177e4
LT
1110 /* Clear old maps */
1111 error = -ENOMEM;
1112munmap_back:
1113 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1114 if (vma && vma->vm_start < addr + len) {
1115 if (do_munmap(mm, addr, len))
1116 return -ENOMEM;
1117 goto munmap_back;
1118 }
1119
1120 /* Check against address space limit. */
119f657c 1121 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
1da177e4
LT
1122 return -ENOMEM;
1123
fc8744ad
LT
1124 /*
1125 * Set 'VM_NORESERVE' if we should not account for the
5a6fe125 1126 * memory use of this mapping.
fc8744ad 1127 */
5a6fe125
MG
1128 if ((flags & MAP_NORESERVE)) {
1129 /* We honor MAP_NORESERVE if allowed to overcommit */
1130 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1131 vm_flags |= VM_NORESERVE;
1132
1133 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1134 if (file && is_file_hugepages(file))
1135 vm_flags |= VM_NORESERVE;
1136 }
cdfd4325 1137
fc8744ad
LT
1138 /*
1139 * Private writable mapping: check memory availability
1140 */
5a6fe125 1141 if (accountable_mapping(file, vm_flags)) {
fc8744ad
LT
1142 charged = len >> PAGE_SHIFT;
1143 if (security_vm_enough_memory(charged))
1144 return -ENOMEM;
1145 vm_flags |= VM_ACCOUNT;
1da177e4
LT
1146 }
1147
1148 /*
de33c8db 1149 * Can we just expand an old mapping?
1da177e4 1150 */
de33c8db
LT
1151 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1152 if (vma)
1153 goto out;
1da177e4
LT
1154
1155 /*
1156 * Determine the object being mapped and call the appropriate
1157 * specific mapper. the address has already been validated, but
1158 * not unmapped, but the maps are removed from the list.
1159 */
c5e3b83e 1160 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1da177e4
LT
1161 if (!vma) {
1162 error = -ENOMEM;
1163 goto unacct_error;
1164 }
1da177e4
LT
1165
1166 vma->vm_mm = mm;
1167 vma->vm_start = addr;
1168 vma->vm_end = addr + len;
1169 vma->vm_flags = vm_flags;
3ed75eb8 1170 vma->vm_page_prot = vm_get_page_prot(vm_flags);
1da177e4
LT
1171 vma->vm_pgoff = pgoff;
1172
1173 if (file) {
1174 error = -EINVAL;
1175 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1176 goto free_vma;
1177 if (vm_flags & VM_DENYWRITE) {
1178 error = deny_write_access(file);
1179 if (error)
1180 goto free_vma;
1181 correct_wcount = 1;
1182 }
1183 vma->vm_file = file;
1184 get_file(file);
1185 error = file->f_op->mmap(file, vma);
1186 if (error)
1187 goto unmap_and_free_vma;
925d1c40
MH
1188 if (vm_flags & VM_EXECUTABLE)
1189 added_exe_file_vma(mm);
f8dbf0a7
HS
1190
1191 /* Can addr have changed??
1192 *
1193 * Answer: Yes, several device drivers can do it in their
1194 * f_op->mmap method. -DaveM
1195 */
1196 addr = vma->vm_start;
1197 pgoff = vma->vm_pgoff;
1198 vm_flags = vma->vm_flags;
1da177e4
LT
1199 } else if (vm_flags & VM_SHARED) {
1200 error = shmem_zero_setup(vma);
1201 if (error)
1202 goto free_vma;
1203 }
1204
d08b3851 1205 if (vma_wants_writenotify(vma))
1ddd439e 1206 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
d08b3851 1207
de33c8db
LT
1208 vma_link(mm, vma, prev, rb_link, rb_parent);
1209 file = vma->vm_file;
4d3d5b41
ON
1210
1211 /* Once vma denies write, undo our temporary denial count */
1212 if (correct_wcount)
1213 atomic_inc(&inode->i_writecount);
1214out:
cdd6c482 1215 perf_event_mmap(vma);
0a4a9391 1216
1da177e4 1217 mm->total_vm += len >> PAGE_SHIFT;
ab50b8ed 1218 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
1da177e4 1219 if (vm_flags & VM_LOCKED) {
ba470de4
RR
1220 /*
1221 * makes pages present; downgrades, drops, reacquires mmap_sem
1222 */
1223 long nr_pages = mlock_vma_pages_range(vma, addr, addr + len);
1224 if (nr_pages < 0)
1225 return nr_pages; /* vma gone! */
1226 mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages;
1227 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
54cb8821 1228 make_pages_present(addr, addr + len);
1da177e4
LT
1229 return addr;
1230
1231unmap_and_free_vma:
1232 if (correct_wcount)
1233 atomic_inc(&inode->i_writecount);
1234 vma->vm_file = NULL;
1235 fput(file);
1236
1237 /* Undo any partial mapping done by a device driver. */
e0da382c
HD
1238 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1239 charged = 0;
1da177e4
LT
1240free_vma:
1241 kmem_cache_free(vm_area_cachep, vma);
1242unacct_error:
1243 if (charged)
1244 vm_unacct_memory(charged);
1245 return error;
1246}
1247
1da177e4
LT
1248/* Get an address range which is currently unmapped.
1249 * For shmat() with addr=0.
1250 *
1251 * Ugly calling convention alert:
1252 * Return value with the low bits set means error value,
1253 * ie
1254 * if (ret & ~PAGE_MASK)
1255 * error = ret;
1256 *
1257 * This function "knows" that -ENOMEM has the bits set.
1258 */
1259#ifndef HAVE_ARCH_UNMAPPED_AREA
1260unsigned long
1261arch_get_unmapped_area(struct file *filp, unsigned long addr,
1262 unsigned long len, unsigned long pgoff, unsigned long flags)
1263{
1264 struct mm_struct *mm = current->mm;
1265 struct vm_area_struct *vma;
1266 unsigned long start_addr;
1267
1268 if (len > TASK_SIZE)
1269 return -ENOMEM;
1270
06abdfb4
BH
1271 if (flags & MAP_FIXED)
1272 return addr;
1273
1da177e4
LT
1274 if (addr) {
1275 addr = PAGE_ALIGN(addr);
1276 vma = find_vma(mm, addr);
1277 if (TASK_SIZE - len >= addr &&
1278 (!vma || addr + len <= vma->vm_start))
1279 return addr;
1280 }
1363c3cd
WW
1281 if (len > mm->cached_hole_size) {
1282 start_addr = addr = mm->free_area_cache;
1283 } else {
1284 start_addr = addr = TASK_UNMAPPED_BASE;
1285 mm->cached_hole_size = 0;
1286 }
1da177e4
LT
1287
1288full_search:
1289 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1290 /* At this point: (!vma || addr < vma->vm_end). */
1291 if (TASK_SIZE - len < addr) {
1292 /*
1293 * Start a new search - just in case we missed
1294 * some holes.
1295 */
1296 if (start_addr != TASK_UNMAPPED_BASE) {
1363c3cd
WW
1297 addr = TASK_UNMAPPED_BASE;
1298 start_addr = addr;
1299 mm->cached_hole_size = 0;
1da177e4
LT
1300 goto full_search;
1301 }
1302 return -ENOMEM;
1303 }
1304 if (!vma || addr + len <= vma->vm_start) {
1305 /*
1306 * Remember the place where we stopped the search:
1307 */
1308 mm->free_area_cache = addr + len;
1309 return addr;
1310 }
1363c3cd
WW
1311 if (addr + mm->cached_hole_size < vma->vm_start)
1312 mm->cached_hole_size = vma->vm_start - addr;
1da177e4
LT
1313 addr = vma->vm_end;
1314 }
1315}
1316#endif
1317
1363c3cd 1318void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1da177e4
LT
1319{
1320 /*
1321 * Is this a new hole at the lowest possible address?
1322 */
1363c3cd
WW
1323 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1324 mm->free_area_cache = addr;
1325 mm->cached_hole_size = ~0UL;
1326 }
1da177e4
LT
1327}
1328
1329/*
1330 * This mmap-allocator allocates new areas top-down from below the
1331 * stack's low limit (the base):
1332 */
1333#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1334unsigned long
1335arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1336 const unsigned long len, const unsigned long pgoff,
1337 const unsigned long flags)
1338{
1339 struct vm_area_struct *vma;
1340 struct mm_struct *mm = current->mm;
1341 unsigned long addr = addr0;
1342
1343 /* requested length too big for entire address space */
1344 if (len > TASK_SIZE)
1345 return -ENOMEM;
1346
06abdfb4
BH
1347 if (flags & MAP_FIXED)
1348 return addr;
1349
1da177e4
LT
1350 /* requesting a specific address */
1351 if (addr) {
1352 addr = PAGE_ALIGN(addr);
1353 vma = find_vma(mm, addr);
1354 if (TASK_SIZE - len >= addr &&
1355 (!vma || addr + len <= vma->vm_start))
1356 return addr;
1357 }
1358
1363c3cd
WW
1359 /* check if free_area_cache is useful for us */
1360 if (len <= mm->cached_hole_size) {
1361 mm->cached_hole_size = 0;
1362 mm->free_area_cache = mm->mmap_base;
1363 }
1364
1da177e4
LT
1365 /* either no address requested or can't fit in requested address hole */
1366 addr = mm->free_area_cache;
1367
1368 /* make sure it can fit in the remaining address space */
49a43876 1369 if (addr > len) {
1da177e4
LT
1370 vma = find_vma(mm, addr-len);
1371 if (!vma || addr <= vma->vm_start)
1372 /* remember the address as a hint for next time */
1373 return (mm->free_area_cache = addr-len);
1374 }
1375
73219d17
CW
1376 if (mm->mmap_base < len)
1377 goto bottomup;
1378
1da177e4
LT
1379 addr = mm->mmap_base-len;
1380
1381 do {
1382 /*
1383 * Lookup failure means no vma is above this address,
1384 * else if new region fits below vma->vm_start,
1385 * return with success:
1386 */
1387 vma = find_vma(mm, addr);
1388 if (!vma || addr+len <= vma->vm_start)
1389 /* remember the address as a hint for next time */
1390 return (mm->free_area_cache = addr);
1391
1363c3cd
WW
1392 /* remember the largest hole we saw so far */
1393 if (addr + mm->cached_hole_size < vma->vm_start)
1394 mm->cached_hole_size = vma->vm_start - addr;
1395
1da177e4
LT
1396 /* try just below the current vma->vm_start */
1397 addr = vma->vm_start-len;
49a43876 1398 } while (len < vma->vm_start);
1da177e4 1399
73219d17 1400bottomup:
1da177e4
LT
1401 /*
1402 * A failed mmap() very likely causes application failure,
1403 * so fall back to the bottom-up function here. This scenario
1404 * can happen with large stack limits and large mmap()
1405 * allocations.
1406 */
1363c3cd
WW
1407 mm->cached_hole_size = ~0UL;
1408 mm->free_area_cache = TASK_UNMAPPED_BASE;
1da177e4
LT
1409 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1410 /*
1411 * Restore the topdown base:
1412 */
1413 mm->free_area_cache = mm->mmap_base;
1363c3cd 1414 mm->cached_hole_size = ~0UL;
1da177e4
LT
1415
1416 return addr;
1417}
1418#endif
1419
1363c3cd 1420void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
1da177e4
LT
1421{
1422 /*
1423 * Is this a new hole at the highest possible address?
1424 */
1363c3cd
WW
1425 if (addr > mm->free_area_cache)
1426 mm->free_area_cache = addr;
1da177e4
LT
1427
1428 /* dont allow allocations above current base */
1363c3cd
WW
1429 if (mm->free_area_cache > mm->mmap_base)
1430 mm->free_area_cache = mm->mmap_base;
1da177e4
LT
1431}
1432
1433unsigned long
1434get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1435 unsigned long pgoff, unsigned long flags)
1436{
06abdfb4
BH
1437 unsigned long (*get_area)(struct file *, unsigned long,
1438 unsigned long, unsigned long, unsigned long);
1439
1440 get_area = current->mm->get_unmapped_area;
1441 if (file && file->f_op && file->f_op->get_unmapped_area)
1442 get_area = file->f_op->get_unmapped_area;
1443 addr = get_area(file, addr, len, pgoff, flags);
1444 if (IS_ERR_VALUE(addr))
1445 return addr;
1da177e4 1446
07ab67c8
LT
1447 if (addr > TASK_SIZE - len)
1448 return -ENOMEM;
1449 if (addr & ~PAGE_MASK)
1450 return -EINVAL;
06abdfb4 1451
08e7d9b5 1452 return arch_rebalance_pgtables(addr, len);
1da177e4
LT
1453}
1454
1455EXPORT_SYMBOL(get_unmapped_area);
1456
1457/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
48aae425 1458struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1da177e4
LT
1459{
1460 struct vm_area_struct *vma = NULL;
1461
1462 if (mm) {
1463 /* Check the cache first. */
1464 /* (Cache hit rate is typically around 35%.) */
1465 vma = mm->mmap_cache;
1466 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1467 struct rb_node * rb_node;
1468
1469 rb_node = mm->mm_rb.rb_node;
1470 vma = NULL;
1471
1472 while (rb_node) {
1473 struct vm_area_struct * vma_tmp;
1474
1475 vma_tmp = rb_entry(rb_node,
1476 struct vm_area_struct, vm_rb);
1477
1478 if (vma_tmp->vm_end > addr) {
1479 vma = vma_tmp;
1480 if (vma_tmp->vm_start <= addr)
1481 break;
1482 rb_node = rb_node->rb_left;
1483 } else
1484 rb_node = rb_node->rb_right;
1485 }
1486 if (vma)
1487 mm->mmap_cache = vma;
1488 }
1489 }
1490 return vma;
1491}
1492
1493EXPORT_SYMBOL(find_vma);
1494
1495/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1496struct vm_area_struct *
1497find_vma_prev(struct mm_struct *mm, unsigned long addr,
1498 struct vm_area_struct **pprev)
1499{
1500 struct vm_area_struct *vma = NULL, *prev = NULL;
48aae425 1501 struct rb_node *rb_node;
1da177e4
LT
1502 if (!mm)
1503 goto out;
1504
1505 /* Guard against addr being lower than the first VMA */
1506 vma = mm->mmap;
1507
1508 /* Go through the RB tree quickly. */
1509 rb_node = mm->mm_rb.rb_node;
1510
1511 while (rb_node) {
1512 struct vm_area_struct *vma_tmp;
1513 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1514
1515 if (addr < vma_tmp->vm_end) {
1516 rb_node = rb_node->rb_left;
1517 } else {
1518 prev = vma_tmp;
1519 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1520 break;
1521 rb_node = rb_node->rb_right;
1522 }
1523 }
1524
1525out:
1526 *pprev = prev;
1527 return prev ? prev->vm_next : vma;
1528}
1529
1530/*
1531 * Verify that the stack growth is acceptable and
1532 * update accounting. This is shared with both the
1533 * grow-up and grow-down cases.
1534 */
48aae425 1535static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
1da177e4
LT
1536{
1537 struct mm_struct *mm = vma->vm_mm;
1538 struct rlimit *rlim = current->signal->rlim;
0d59a01b 1539 unsigned long new_start;
1da177e4
LT
1540
1541 /* address space limit tests */
119f657c 1542 if (!may_expand_vm(mm, grow))
1da177e4
LT
1543 return -ENOMEM;
1544
1545 /* Stack limit test */
1546 if (size > rlim[RLIMIT_STACK].rlim_cur)
1547 return -ENOMEM;
1548
1549 /* mlock limit tests */
1550 if (vma->vm_flags & VM_LOCKED) {
1551 unsigned long locked;
1552 unsigned long limit;
1553 locked = mm->locked_vm + grow;
1554 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1555 if (locked > limit && !capable(CAP_IPC_LOCK))
1556 return -ENOMEM;
1557 }
1558
0d59a01b
AL
1559 /* Check to ensure the stack will not grow into a hugetlb-only region */
1560 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1561 vma->vm_end - size;
1562 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1563 return -EFAULT;
1564
1da177e4
LT
1565 /*
1566 * Overcommit.. This must be the final test, as it will
1567 * update security statistics.
1568 */
05fa199d 1569 if (security_vm_enough_memory_mm(mm, grow))
1da177e4
LT
1570 return -ENOMEM;
1571
1572 /* Ok, everything looks good - let it rip */
1573 mm->total_vm += grow;
1574 if (vma->vm_flags & VM_LOCKED)
1575 mm->locked_vm += grow;
ab50b8ed 1576 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
1da177e4
LT
1577 return 0;
1578}
1579
46dea3d0 1580#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1da177e4 1581/*
46dea3d0
HD
1582 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1583 * vma is the last one with address > vma->vm_end. Have to extend vma.
1da177e4 1584 */
9ab88515 1585#ifndef CONFIG_IA64
cb8f488c 1586static
46dea3d0
HD
1587#endif
1588int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1da177e4
LT
1589{
1590 int error;
1591
1592 if (!(vma->vm_flags & VM_GROWSUP))
1593 return -EFAULT;
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.
06b32f3a 1607 * Also guard against wrapping around to address 0.
1da177e4 1608 */
06b32f3a
HD
1609 if (address < PAGE_ALIGN(address+4))
1610 address = PAGE_ALIGN(address+4);
1611 else {
1612 anon_vma_unlock(vma);
1613 return -ENOMEM;
1614 }
1da177e4
LT
1615 error = 0;
1616
1617 /* Somebody else might have raced and expanded it already */
1618 if (address > vma->vm_end) {
1619 unsigned long size, grow;
1620
1621 size = address - vma->vm_start;
1622 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1623
1624 error = acct_stack_growth(vma, size, grow);
1625 if (!error)
1626 vma->vm_end = address;
1627 }
1628 anon_vma_unlock(vma);
1629 return error;
1630}
46dea3d0
HD
1631#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1632
1da177e4
LT
1633/*
1634 * vma is the first one with address < vma->vm_start. Have to extend vma.
1635 */
cb8f488c 1636static int expand_downwards(struct vm_area_struct *vma,
b6a2fea3 1637 unsigned long address)
1da177e4
LT
1638{
1639 int error;
1640
1641 /*
1642 * We must make sure the anon_vma is allocated
1643 * so that the anon_vma locking is not a noop.
1644 */
1645 if (unlikely(anon_vma_prepare(vma)))
1646 return -ENOMEM;
8869477a
EP
1647
1648 address &= PAGE_MASK;
88c3f7a8 1649 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
8869477a
EP
1650 if (error)
1651 return error;
1652
1da177e4
LT
1653 anon_vma_lock(vma);
1654
1655 /*
1656 * vma->vm_start/vm_end cannot change under us because the caller
1657 * is required to hold the mmap_sem in read mode. We need the
1658 * anon_vma lock to serialize against concurrent expand_stacks.
1659 */
1da177e4
LT
1660
1661 /* Somebody else might have raced and expanded it already */
1662 if (address < vma->vm_start) {
1663 unsigned long size, grow;
1664
1665 size = vma->vm_end - address;
1666 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1667
1668 error = acct_stack_growth(vma, size, grow);
1669 if (!error) {
1670 vma->vm_start = address;
1671 vma->vm_pgoff -= grow;
1672 }
1673 }
1674 anon_vma_unlock(vma);
1675 return error;
1676}
1677
b6a2fea3
OW
1678int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1679{
1680 return expand_downwards(vma, address);
1681}
1682
1683#ifdef CONFIG_STACK_GROWSUP
1684int expand_stack(struct vm_area_struct *vma, unsigned long address)
1685{
1686 return expand_upwards(vma, address);
1687}
1688
1689struct vm_area_struct *
1690find_extend_vma(struct mm_struct *mm, unsigned long addr)
1691{
1692 struct vm_area_struct *vma, *prev;
1693
1694 addr &= PAGE_MASK;
1695 vma = find_vma_prev(mm, addr, &prev);
1696 if (vma && (vma->vm_start <= addr))
1697 return vma;
1c127185 1698 if (!prev || expand_stack(prev, addr))
b6a2fea3 1699 return NULL;
ba470de4
RR
1700 if (prev->vm_flags & VM_LOCKED) {
1701 if (mlock_vma_pages_range(prev, addr, prev->vm_end) < 0)
1702 return NULL; /* vma gone! */
1703 }
b6a2fea3
OW
1704 return prev;
1705}
1706#else
1707int expand_stack(struct vm_area_struct *vma, unsigned long address)
1708{
1709 return expand_downwards(vma, address);
1710}
1711
1da177e4
LT
1712struct vm_area_struct *
1713find_extend_vma(struct mm_struct * mm, unsigned long addr)
1714{
1715 struct vm_area_struct * vma;
1716 unsigned long start;
1717
1718 addr &= PAGE_MASK;
1719 vma = find_vma(mm,addr);
1720 if (!vma)
1721 return NULL;
1722 if (vma->vm_start <= addr)
1723 return vma;
1724 if (!(vma->vm_flags & VM_GROWSDOWN))
1725 return NULL;
1726 start = vma->vm_start;
1727 if (expand_stack(vma, addr))
1728 return NULL;
ba470de4
RR
1729 if (vma->vm_flags & VM_LOCKED) {
1730 if (mlock_vma_pages_range(vma, addr, start) < 0)
1731 return NULL; /* vma gone! */
1732 }
1da177e4
LT
1733 return vma;
1734}
1735#endif
1736
1da177e4 1737/*
2c0b3814 1738 * Ok - we have the memory areas we should free on the vma list,
1da177e4 1739 * so release them, and do the vma updates.
2c0b3814
HD
1740 *
1741 * Called with the mm semaphore held.
1da177e4 1742 */
2c0b3814 1743static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
1da177e4 1744{
365e9c87
HD
1745 /* Update high watermark before we lower total_vm */
1746 update_hiwater_vm(mm);
1da177e4 1747 do {
2c0b3814
HD
1748 long nrpages = vma_pages(vma);
1749
1750 mm->total_vm -= nrpages;
2c0b3814 1751 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
a8fb5618 1752 vma = remove_vma(vma);
146425a3 1753 } while (vma);
1da177e4
LT
1754 validate_mm(mm);
1755}
1756
1757/*
1758 * Get rid of page table information in the indicated region.
1759 *
f10df686 1760 * Called with the mm semaphore held.
1da177e4
LT
1761 */
1762static void unmap_region(struct mm_struct *mm,
e0da382c
HD
1763 struct vm_area_struct *vma, struct vm_area_struct *prev,
1764 unsigned long start, unsigned long end)
1da177e4 1765{
e0da382c 1766 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
1da177e4
LT
1767 struct mmu_gather *tlb;
1768 unsigned long nr_accounted = 0;
1769
1770 lru_add_drain();
1771 tlb = tlb_gather_mmu(mm, 0);
365e9c87 1772 update_hiwater_rss(mm);
508034a3 1773 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
1da177e4 1774 vm_unacct_memory(nr_accounted);
42b77728 1775 free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
e0da382c 1776 next? next->vm_start: 0);
1da177e4
LT
1777 tlb_finish_mmu(tlb, start, end);
1778}
1779
1780/*
1781 * Create a list of vma's touched by the unmap, removing them from the mm's
1782 * vma list as we go..
1783 */
1784static void
1785detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1786 struct vm_area_struct *prev, unsigned long end)
1787{
1788 struct vm_area_struct **insertion_point;
1789 struct vm_area_struct *tail_vma = NULL;
1363c3cd 1790 unsigned long addr;
1da177e4
LT
1791
1792 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1793 do {
1794 rb_erase(&vma->vm_rb, &mm->mm_rb);
1795 mm->map_count--;
1796 tail_vma = vma;
1797 vma = vma->vm_next;
1798 } while (vma && vma->vm_start < end);
1799 *insertion_point = vma;
1800 tail_vma->vm_next = NULL;
1363c3cd
WW
1801 if (mm->unmap_area == arch_unmap_area)
1802 addr = prev ? prev->vm_end : mm->mmap_base;
1803 else
1804 addr = vma ? vma->vm_start : mm->mmap_base;
1805 mm->unmap_area(mm, addr);
1da177e4
LT
1806 mm->mmap_cache = NULL; /* Kill the cache. */
1807}
1808
1809/*
1810 * Split a vma into two pieces at address 'addr', a new vma is allocated
59c51591 1811 * either for the first part or the tail.
1da177e4
LT
1812 */
1813int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1814 unsigned long addr, int new_below)
1815{
1816 struct mempolicy *pol;
1817 struct vm_area_struct *new;
1818
a5516438
AK
1819 if (is_vm_hugetlb_page(vma) && (addr &
1820 ~(huge_page_mask(hstate_vma(vma)))))
1da177e4
LT
1821 return -EINVAL;
1822
1823 if (mm->map_count >= sysctl_max_map_count)
1824 return -ENOMEM;
1825
e94b1766 1826 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1da177e4
LT
1827 if (!new)
1828 return -ENOMEM;
1829
1830 /* most fields are the same, copy all, and then fixup */
1831 *new = *vma;
1832
1833 if (new_below)
1834 new->vm_end = addr;
1835 else {
1836 new->vm_start = addr;
1837 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1838 }
1839
846a16bf 1840 pol = mpol_dup(vma_policy(vma));
1da177e4
LT
1841 if (IS_ERR(pol)) {
1842 kmem_cache_free(vm_area_cachep, new);
1843 return PTR_ERR(pol);
1844 }
1845 vma_set_policy(new, pol);
1846
925d1c40 1847 if (new->vm_file) {
1da177e4 1848 get_file(new->vm_file);
925d1c40
MH
1849 if (vma->vm_flags & VM_EXECUTABLE)
1850 added_exe_file_vma(mm);
1851 }
1da177e4
LT
1852
1853 if (new->vm_ops && new->vm_ops->open)
1854 new->vm_ops->open(new);
1855
1856 if (new_below)
1857 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1858 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1859 else
1860 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1861
1862 return 0;
1863}
1864
1865/* Munmap is split into 2 main parts -- this part which finds
1866 * what needs doing, and the areas themselves, which do the
1867 * work. This now handles partial unmappings.
1868 * Jeremy Fitzhardinge <jeremy@goop.org>
1869 */
1870int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1871{
1872 unsigned long end;
146425a3 1873 struct vm_area_struct *vma, *prev, *last;
1da177e4
LT
1874
1875 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1876 return -EINVAL;
1877
1878 if ((len = PAGE_ALIGN(len)) == 0)
1879 return -EINVAL;
1880
1881 /* Find the first overlapping VMA */
146425a3
HD
1882 vma = find_vma_prev(mm, start, &prev);
1883 if (!vma)
1da177e4 1884 return 0;
146425a3 1885 /* we have start < vma->vm_end */
1da177e4
LT
1886
1887 /* if it doesn't overlap, we have nothing.. */
1888 end = start + len;
146425a3 1889 if (vma->vm_start >= end)
1da177e4
LT
1890 return 0;
1891
1892 /*
1893 * If we need to split any vma, do it now to save pain later.
1894 *
1895 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1896 * unmapped vm_area_struct will remain in use: so lower split_vma
1897 * places tmp vma above, and higher split_vma places tmp vma below.
1898 */
146425a3
HD
1899 if (start > vma->vm_start) {
1900 int error = split_vma(mm, vma, start, 0);
1da177e4
LT
1901 if (error)
1902 return error;
146425a3 1903 prev = vma;
1da177e4
LT
1904 }
1905
1906 /* Does it split the last one? */
1907 last = find_vma(mm, end);
1908 if (last && end > last->vm_start) {
1909 int error = split_vma(mm, last, end, 1);
1910 if (error)
1911 return error;
1912 }
146425a3 1913 vma = prev? prev->vm_next: mm->mmap;
1da177e4 1914
ba470de4
RR
1915 /*
1916 * unlock any mlock()ed ranges before detaching vmas
1917 */
1918 if (mm->locked_vm) {
1919 struct vm_area_struct *tmp = vma;
1920 while (tmp && tmp->vm_start < end) {
1921 if (tmp->vm_flags & VM_LOCKED) {
1922 mm->locked_vm -= vma_pages(tmp);
1923 munlock_vma_pages_all(tmp);
1924 }
1925 tmp = tmp->vm_next;
1926 }
1927 }
1928
1da177e4
LT
1929 /*
1930 * Remove the vma's, and unmap the actual pages
1931 */
146425a3
HD
1932 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1933 unmap_region(mm, vma, prev, start, end);
1da177e4
LT
1934
1935 /* Fix up all other VM information */
2c0b3814 1936 remove_vma_list(mm, vma);
1da177e4
LT
1937
1938 return 0;
1939}
1940
1941EXPORT_SYMBOL(do_munmap);
1942
6a6160a7 1943SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1da177e4
LT
1944{
1945 int ret;
1946 struct mm_struct *mm = current->mm;
1947
1948 profile_munmap(addr);
1949
1950 down_write(&mm->mmap_sem);
1951 ret = do_munmap(mm, addr, len);
1952 up_write(&mm->mmap_sem);
1953 return ret;
1954}
1955
1956static inline void verify_mm_writelocked(struct mm_struct *mm)
1957{
a241ec65 1958#ifdef CONFIG_DEBUG_VM
1da177e4
LT
1959 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1960 WARN_ON(1);
1961 up_read(&mm->mmap_sem);
1962 }
1963#endif
1964}
1965
1966/*
1967 * this is really a simplified "do_mmap". it only handles
1968 * anonymous maps. eventually we may be able to do some
1969 * brk-specific accounting here.
1970 */
1971unsigned long do_brk(unsigned long addr, unsigned long len)
1972{
1973 struct mm_struct * mm = current->mm;
1974 struct vm_area_struct * vma, * prev;
1975 unsigned long flags;
1976 struct rb_node ** rb_link, * rb_parent;
1977 pgoff_t pgoff = addr >> PAGE_SHIFT;
3a459756 1978 int error;
1da177e4
LT
1979
1980 len = PAGE_ALIGN(len);
1981 if (!len)
1982 return addr;
1983
1984 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1985 return -EINVAL;
1986
cd2579d7
HD
1987 if (is_hugepage_only_range(mm, addr, len))
1988 return -EINVAL;
cb07c9a1 1989
88c3f7a8 1990 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
5a211a5d
EP
1991 if (error)
1992 return error;
1993
3a459756
KK
1994 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1995
1996 error = arch_mmap_check(addr, len, flags);
1997 if (error)
1998 return error;
1999
1da177e4
LT
2000 /*
2001 * mlock MCL_FUTURE?
2002 */
2003 if (mm->def_flags & VM_LOCKED) {
2004 unsigned long locked, lock_limit;
93ea1d0a
CW
2005 locked = len >> PAGE_SHIFT;
2006 locked += mm->locked_vm;
1da177e4 2007 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
93ea1d0a 2008 lock_limit >>= PAGE_SHIFT;
1da177e4
LT
2009 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2010 return -EAGAIN;
2011 }
2012
2013 /*
2014 * mm->mmap_sem is required to protect against another thread
2015 * changing the mappings in case we sleep.
2016 */
2017 verify_mm_writelocked(mm);
2018
2019 /*
2020 * Clear old maps. this also does some error checking for us
2021 */
2022 munmap_back:
2023 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2024 if (vma && vma->vm_start < addr + len) {
2025 if (do_munmap(mm, addr, len))
2026 return -ENOMEM;
2027 goto munmap_back;
2028 }
2029
2030 /* Check against address space limits *after* clearing old maps... */
119f657c 2031 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
1da177e4
LT
2032 return -ENOMEM;
2033
2034 if (mm->map_count > sysctl_max_map_count)
2035 return -ENOMEM;
2036
2037 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2038 return -ENOMEM;
2039
1da177e4 2040 /* Can we just expand an old private anonymous mapping? */
ba470de4
RR
2041 vma = vma_merge(mm, prev, addr, addr + len, flags,
2042 NULL, NULL, pgoff, NULL);
2043 if (vma)
1da177e4
LT
2044 goto out;
2045
2046 /*
2047 * create a vma struct for an anonymous mapping
2048 */
c5e3b83e 2049 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1da177e4
LT
2050 if (!vma) {
2051 vm_unacct_memory(len >> PAGE_SHIFT);
2052 return -ENOMEM;
2053 }
1da177e4
LT
2054
2055 vma->vm_mm = mm;
2056 vma->vm_start = addr;
2057 vma->vm_end = addr + len;
2058 vma->vm_pgoff = pgoff;
2059 vma->vm_flags = flags;
3ed75eb8 2060 vma->vm_page_prot = vm_get_page_prot(flags);
1da177e4
LT
2061 vma_link(mm, vma, prev, rb_link, rb_parent);
2062out:
2063 mm->total_vm += len >> PAGE_SHIFT;
2064 if (flags & VM_LOCKED) {
ba470de4
RR
2065 if (!mlock_vma_pages_range(vma, addr, addr + len))
2066 mm->locked_vm += (len >> PAGE_SHIFT);
1da177e4
LT
2067 }
2068 return addr;
2069}
2070
2071EXPORT_SYMBOL(do_brk);
2072
2073/* Release all mmaps. */
2074void exit_mmap(struct mm_struct *mm)
2075{
2076 struct mmu_gather *tlb;
ba470de4 2077 struct vm_area_struct *vma;
1da177e4 2078 unsigned long nr_accounted = 0;
ee39b37b 2079 unsigned long end;
1da177e4 2080
d6dd61c8 2081 /* mm's last user has gone, and its about to be pulled down */
cddb8a5c 2082 mmu_notifier_release(mm);
d6dd61c8 2083
ba470de4
RR
2084 if (mm->locked_vm) {
2085 vma = mm->mmap;
2086 while (vma) {
2087 if (vma->vm_flags & VM_LOCKED)
2088 munlock_vma_pages_all(vma);
2089 vma = vma->vm_next;
2090 }
2091 }
9480c53e
JF
2092
2093 arch_exit_mmap(mm);
2094
ba470de4 2095 vma = mm->mmap;
9480c53e
JF
2096 if (!vma) /* Can happen if dup_mmap() received an OOM */
2097 return;
2098
1da177e4 2099 lru_add_drain();
1da177e4 2100 flush_cache_mm(mm);
e0da382c 2101 tlb = tlb_gather_mmu(mm, 1);
901608d9 2102 /* update_hiwater_rss(mm) here? but nobody should be looking */
e0da382c 2103 /* Use -1 here to ensure all VMAs in the mm are unmapped */
508034a3 2104 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
1da177e4 2105 vm_unacct_memory(nr_accounted);
9ba69294 2106
42b77728 2107 free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
ee39b37b 2108 tlb_finish_mmu(tlb, 0, end);
1da177e4 2109
1da177e4 2110 /*
8f4f8c16
HD
2111 * Walk the list again, actually closing and freeing it,
2112 * with preemption enabled, without holding any MM locks.
1da177e4 2113 */
a8fb5618
HD
2114 while (vma)
2115 vma = remove_vma(vma);
e0da382c 2116
e2cdef8c 2117 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
1da177e4
LT
2118}
2119
2120/* Insert vm structure into process list sorted by address
2121 * and into the inode's i_mmap tree. If vm_file is non-NULL
2122 * then i_mmap_lock is taken here.
2123 */
2124int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2125{
2126 struct vm_area_struct * __vma, * prev;
2127 struct rb_node ** rb_link, * rb_parent;
2128
2129 /*
2130 * The vm_pgoff of a purely anonymous vma should be irrelevant
2131 * until its first write fault, when page's anon_vma and index
2132 * are set. But now set the vm_pgoff it will almost certainly
2133 * end up with (unless mremap moves it elsewhere before that
2134 * first wfault), so /proc/pid/maps tells a consistent story.
2135 *
2136 * By setting it to reflect the virtual start address of the
2137 * vma, merges and splits can happen in a seamless way, just
2138 * using the existing file pgoff checks and manipulations.
2139 * Similarly in do_mmap_pgoff and in do_brk.
2140 */
2141 if (!vma->vm_file) {
2142 BUG_ON(vma->anon_vma);
2143 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2144 }
2145 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2146 if (__vma && __vma->vm_start < vma->vm_end)
2147 return -ENOMEM;
2fd4ef85 2148 if ((vma->vm_flags & VM_ACCOUNT) &&
34b4e4aa 2149 security_vm_enough_memory_mm(mm, vma_pages(vma)))
2fd4ef85 2150 return -ENOMEM;
1da177e4
LT
2151 vma_link(mm, vma, prev, rb_link, rb_parent);
2152 return 0;
2153}
2154
2155/*
2156 * Copy the vma structure to a new location in the same mm,
2157 * prior to moving page table entries, to effect an mremap move.
2158 */
2159struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2160 unsigned long addr, unsigned long len, pgoff_t pgoff)
2161{
2162 struct vm_area_struct *vma = *vmap;
2163 unsigned long vma_start = vma->vm_start;
2164 struct mm_struct *mm = vma->vm_mm;
2165 struct vm_area_struct *new_vma, *prev;
2166 struct rb_node **rb_link, *rb_parent;
2167 struct mempolicy *pol;
2168
2169 /*
2170 * If anonymous vma has not yet been faulted, update new pgoff
2171 * to match new location, to increase its chance of merging.
2172 */
2173 if (!vma->vm_file && !vma->anon_vma)
2174 pgoff = addr >> PAGE_SHIFT;
2175
2176 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2177 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2178 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2179 if (new_vma) {
2180 /*
2181 * Source vma may have been merged into new_vma
2182 */
2183 if (vma_start >= new_vma->vm_start &&
2184 vma_start < new_vma->vm_end)
2185 *vmap = new_vma;
2186 } else {
e94b1766 2187 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1da177e4
LT
2188 if (new_vma) {
2189 *new_vma = *vma;
846a16bf 2190 pol = mpol_dup(vma_policy(vma));
1da177e4
LT
2191 if (IS_ERR(pol)) {
2192 kmem_cache_free(vm_area_cachep, new_vma);
2193 return NULL;
2194 }
2195 vma_set_policy(new_vma, pol);
2196 new_vma->vm_start = addr;
2197 new_vma->vm_end = addr + len;
2198 new_vma->vm_pgoff = pgoff;
925d1c40 2199 if (new_vma->vm_file) {
1da177e4 2200 get_file(new_vma->vm_file);
925d1c40
MH
2201 if (vma->vm_flags & VM_EXECUTABLE)
2202 added_exe_file_vma(mm);
2203 }
1da177e4
LT
2204 if (new_vma->vm_ops && new_vma->vm_ops->open)
2205 new_vma->vm_ops->open(new_vma);
2206 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2207 }
2208 }
2209 return new_vma;
2210}
119f657c
AM
2211
2212/*
2213 * Return true if the calling process may expand its vm space by the passed
2214 * number of pages
2215 */
2216int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2217{
2218 unsigned long cur = mm->total_vm; /* pages */
2219 unsigned long lim;
2220
2221 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2222
2223 if (cur + npages > lim)
2224 return 0;
2225 return 1;
2226}
fa5dc22f
RM
2227
2228
b1d0e4f5
NP
2229static int special_mapping_fault(struct vm_area_struct *vma,
2230 struct vm_fault *vmf)
fa5dc22f 2231{
b1d0e4f5 2232 pgoff_t pgoff;
fa5dc22f
RM
2233 struct page **pages;
2234
b1d0e4f5
NP
2235 /*
2236 * special mappings have no vm_file, and in that case, the mm
2237 * uses vm_pgoff internally. So we have to subtract it from here.
2238 * We are allowed to do this because we are the mm; do not copy
2239 * this code into drivers!
2240 */
2241 pgoff = vmf->pgoff - vma->vm_pgoff;
fa5dc22f 2242
b1d0e4f5
NP
2243 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2244 pgoff--;
fa5dc22f
RM
2245
2246 if (*pages) {
2247 struct page *page = *pages;
2248 get_page(page);
b1d0e4f5
NP
2249 vmf->page = page;
2250 return 0;
fa5dc22f
RM
2251 }
2252
b1d0e4f5 2253 return VM_FAULT_SIGBUS;
fa5dc22f
RM
2254}
2255
2256/*
2257 * Having a close hook prevents vma merging regardless of flags.
2258 */
2259static void special_mapping_close(struct vm_area_struct *vma)
2260{
2261}
2262
f0f37e2f 2263static const struct vm_operations_struct special_mapping_vmops = {
fa5dc22f 2264 .close = special_mapping_close,
b1d0e4f5 2265 .fault = special_mapping_fault,
fa5dc22f
RM
2266};
2267
2268/*
2269 * Called with mm->mmap_sem held for writing.
2270 * Insert a new vma covering the given region, with the given flags.
2271 * Its pages are supplied by the given array of struct page *.
2272 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2273 * The region past the last page supplied will always produce SIGBUS.
2274 * The array pointer and the pages it points to are assumed to stay alive
2275 * for as long as this mapping might exist.
2276 */
2277int install_special_mapping(struct mm_struct *mm,
2278 unsigned long addr, unsigned long len,
2279 unsigned long vm_flags, struct page **pages)
2280{
2281 struct vm_area_struct *vma;
2282
2283 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2284 if (unlikely(vma == NULL))
2285 return -ENOMEM;
2286
2287 vma->vm_mm = mm;
2288 vma->vm_start = addr;
2289 vma->vm_end = addr + len;
2290
2f98735c 2291 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
3ed75eb8 2292 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
fa5dc22f
RM
2293
2294 vma->vm_ops = &special_mapping_vmops;
2295 vma->vm_private_data = pages;
2296
2297 if (unlikely(insert_vm_struct(mm, vma))) {
2298 kmem_cache_free(vm_area_cachep, vma);
2299 return -ENOMEM;
2300 }
2301
2302 mm->total_vm += len >> PAGE_SHIFT;
2303
cdd6c482 2304 perf_event_mmap(vma);
089dd79d 2305
fa5dc22f
RM
2306 return 0;
2307}
7906d00c
AA
2308
2309static DEFINE_MUTEX(mm_all_locks_mutex);
2310
454ed842 2311static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
7906d00c
AA
2312{
2313 if (!test_bit(0, (unsigned long *) &anon_vma->head.next)) {
2314 /*
2315 * The LSB of head.next can't change from under us
2316 * because we hold the mm_all_locks_mutex.
2317 */
454ed842 2318 spin_lock_nest_lock(&anon_vma->lock, &mm->mmap_sem);
7906d00c
AA
2319 /*
2320 * We can safely modify head.next after taking the
2321 * anon_vma->lock. If some other vma in this mm shares
2322 * the same anon_vma we won't take it again.
2323 *
2324 * No need of atomic instructions here, head.next
2325 * can't change from under us thanks to the
2326 * anon_vma->lock.
2327 */
2328 if (__test_and_set_bit(0, (unsigned long *)
2329 &anon_vma->head.next))
2330 BUG();
2331 }
2332}
2333
454ed842 2334static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
7906d00c
AA
2335{
2336 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2337 /*
2338 * AS_MM_ALL_LOCKS can't change from under us because
2339 * we hold the mm_all_locks_mutex.
2340 *
2341 * Operations on ->flags have to be atomic because
2342 * even if AS_MM_ALL_LOCKS is stable thanks to the
2343 * mm_all_locks_mutex, there may be other cpus
2344 * changing other bitflags in parallel to us.
2345 */
2346 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2347 BUG();
454ed842 2348 spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem);
7906d00c
AA
2349 }
2350}
2351
2352/*
2353 * This operation locks against the VM for all pte/vma/mm related
2354 * operations that could ever happen on a certain mm. This includes
2355 * vmtruncate, try_to_unmap, and all page faults.
2356 *
2357 * The caller must take the mmap_sem in write mode before calling
2358 * mm_take_all_locks(). The caller isn't allowed to release the
2359 * mmap_sem until mm_drop_all_locks() returns.
2360 *
2361 * mmap_sem in write mode is required in order to block all operations
2362 * that could modify pagetables and free pages without need of
2363 * altering the vma layout (for example populate_range() with
2364 * nonlinear vmas). It's also needed in write mode to avoid new
2365 * anon_vmas to be associated with existing vmas.
2366 *
2367 * A single task can't take more than one mm_take_all_locks() in a row
2368 * or it would deadlock.
2369 *
2370 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2371 * mapping->flags avoid to take the same lock twice, if more than one
2372 * vma in this mm is backed by the same anon_vma or address_space.
2373 *
2374 * We can take all the locks in random order because the VM code
2375 * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never
2376 * takes more than one of them in a row. Secondly we're protected
2377 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2378 *
2379 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2380 * that may have to take thousand of locks.
2381 *
2382 * mm_take_all_locks() can fail if it's interrupted by signals.
2383 */
2384int mm_take_all_locks(struct mm_struct *mm)
2385{
2386 struct vm_area_struct *vma;
2387 int ret = -EINTR;
2388
2389 BUG_ON(down_read_trylock(&mm->mmap_sem));
2390
2391 mutex_lock(&mm_all_locks_mutex);
2392
2393 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2394 if (signal_pending(current))
2395 goto out_unlock;
7906d00c 2396 if (vma->vm_file && vma->vm_file->f_mapping)
454ed842 2397 vm_lock_mapping(mm, vma->vm_file->f_mapping);
7906d00c 2398 }
7cd5a02f
PZ
2399
2400 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2401 if (signal_pending(current))
2402 goto out_unlock;
2403 if (vma->anon_vma)
2404 vm_lock_anon_vma(mm, vma->anon_vma);
7906d00c 2405 }
7cd5a02f 2406
7906d00c
AA
2407 ret = 0;
2408
2409out_unlock:
2410 if (ret)
2411 mm_drop_all_locks(mm);
2412
2413 return ret;
2414}
2415
2416static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2417{
2418 if (test_bit(0, (unsigned long *) &anon_vma->head.next)) {
2419 /*
2420 * The LSB of head.next can't change to 0 from under
2421 * us because we hold the mm_all_locks_mutex.
2422 *
2423 * We must however clear the bitflag before unlocking
2424 * the vma so the users using the anon_vma->head will
2425 * never see our bitflag.
2426 *
2427 * No need of atomic instructions here, head.next
2428 * can't change from under us until we release the
2429 * anon_vma->lock.
2430 */
2431 if (!__test_and_clear_bit(0, (unsigned long *)
2432 &anon_vma->head.next))
2433 BUG();
2434 spin_unlock(&anon_vma->lock);
2435 }
2436}
2437
2438static void vm_unlock_mapping(struct address_space *mapping)
2439{
2440 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2441 /*
2442 * AS_MM_ALL_LOCKS can't change to 0 from under us
2443 * because we hold the mm_all_locks_mutex.
2444 */
2445 spin_unlock(&mapping->i_mmap_lock);
2446 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2447 &mapping->flags))
2448 BUG();
2449 }
2450}
2451
2452/*
2453 * The mmap_sem cannot be released by the caller until
2454 * mm_drop_all_locks() returns.
2455 */
2456void mm_drop_all_locks(struct mm_struct *mm)
2457{
2458 struct vm_area_struct *vma;
2459
2460 BUG_ON(down_read_trylock(&mm->mmap_sem));
2461 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2462
2463 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2464 if (vma->anon_vma)
2465 vm_unlock_anon_vma(vma->anon_vma);
2466 if (vma->vm_file && vma->vm_file->f_mapping)
2467 vm_unlock_mapping(vma->vm_file->f_mapping);
2468 }
2469
2470 mutex_unlock(&mm_all_locks_mutex);
2471}
8feae131
DH
2472
2473/*
2474 * initialise the VMA slab
2475 */
2476void __init mmap_init(void)
2477{
00a62ce9
KM
2478 int ret;
2479
2480 ret = percpu_counter_init(&vm_committed_as, 0);
2481 VM_BUG_ON(ret);
8feae131 2482}