blob: 5e0cc99e9cd57704a1019dc2c6764d895ad3d756 [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>
29
30#include <asm/uaccess.h>
31#include <asm/cacheflush.h>
32#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020033#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Jan Beulich42b77722008-07-23 21:27:10 -070035#include "internal.h"
36
Kirill Korotaev3a459752006-09-07 14:17:04 +040037#ifndef arch_mmap_check
38#define arch_mmap_check(addr, len, flags) (0)
39#endif
40
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080041#ifndef arch_rebalance_pgtables
42#define arch_rebalance_pgtables(addr, len) (addr)
43#endif
44
Hugh Dickinse0da3822005-04-19 13:29:15 -070045static void unmap_region(struct mm_struct *mm,
46 struct vm_area_struct *vma, struct vm_area_struct *prev,
47 unsigned long start, unsigned long end);
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/*
50 * WARNING: the debugging will use recursive algorithms so never enable this
51 * unless you know what you are doing.
52 */
53#undef DEBUG_MM_RB
54
55/* description of effects of mapping type and prot in current implementation.
56 * this is due to the limited x86 page protection hardware. The expected
57 * behavior is in parens:
58 *
59 * map_type prot
60 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
61 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
62 * w: (no) no w: (no) no w: (yes) yes w: (no) no
63 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
64 *
65 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (copy) copy w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 */
70pgprot_t protection_map[16] = {
71 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
72 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
73};
74
Hugh Dickins804af2c2006-07-26 21:39:49 +010075pgprot_t vm_get_page_prot(unsigned long vm_flags)
76{
Dave Kleikampb845f312008-07-08 00:28:51 +100077 return __pgprot(pgprot_val(protection_map[vm_flags &
78 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
79 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010080}
81EXPORT_SYMBOL(vm_get_page_prot);
82
Linus Torvalds1da177e2005-04-16 15:20:36 -070083int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
84int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070085int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Alan Cox80119ef2008-05-23 13:04:31 -070086atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
88/*
89 * Check that a process has enough memory to allocate a new virtual
90 * mapping. 0 means there is enough memory for the allocation to
91 * succeed and -ENOMEM implies there is not.
92 *
93 * We currently support three overcommit policies, which are set via the
94 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
95 *
96 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
97 * Additional code 2002 Jul 20 by Robert Love.
98 *
99 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
100 *
101 * Note this is a helper function intended to be used by LSMs which
102 * wish to use this logic.
103 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700104int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105{
106 unsigned long free, allowed;
107
108 vm_acct_memory(pages);
109
110 /*
111 * Sometimes we want to use more memory than we have
112 */
113 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
114 return 0;
115
116 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
117 unsigned long n;
118
Christoph Lameter347ce432006-06-30 01:55:35 -0700119 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 free += nr_swap_pages;
121
122 /*
123 * Any slabs which are created with the
124 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
125 * which are reclaimable, under pressure. The dentry
126 * cache and most inode caches should fall into this
127 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700128 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
130 /*
131 * Leave the last 3% for root
132 */
133 if (!cap_sys_admin)
134 free -= free / 32;
135
136 if (free > pages)
137 return 0;
138
139 /*
140 * nr_free_pages() is very expensive on large systems,
141 * only call if we're about to fail.
142 */
143 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700144
145 /*
146 * Leave reserved pages. The pages are not for anonymous pages.
147 */
148 if (n <= totalreserve_pages)
149 goto error;
150 else
151 n -= totalreserve_pages;
152
153 /*
154 * Leave the last 3% for root
155 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 if (!cap_sys_admin)
157 n -= n / 32;
158 free += n;
159
160 if (free > pages)
161 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700162
163 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 }
165
166 allowed = (totalram_pages - hugetlb_total_pages())
167 * sysctl_overcommit_ratio / 100;
168 /*
169 * Leave the last 3% for root
170 */
171 if (!cap_sys_admin)
172 allowed -= allowed / 32;
173 allowed += total_swap_pages;
174
175 /* Don't let a single process grow too big:
176 leave 3% of the size of this process for other processes */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700177 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Simon Derr2f60f8d2005-08-04 19:52:03 -0700179 /*
180 * cast `allowed' as a signed long because vm_committed_space
181 * sometimes has a negative value
182 */
Alan Cox80119ef2008-05-23 13:04:31 -0700183 if (atomic_long_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700185error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 vm_unacct_memory(pages);
187
188 return -ENOMEM;
189}
190
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191/*
192 * Requires inode->i_mapping->i_mmap_lock
193 */
194static void __remove_shared_vm_struct(struct vm_area_struct *vma,
195 struct file *file, struct address_space *mapping)
196{
197 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800198 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 if (vma->vm_flags & VM_SHARED)
200 mapping->i_mmap_writable--;
201
202 flush_dcache_mmap_lock(mapping);
203 if (unlikely(vma->vm_flags & VM_NONLINEAR))
204 list_del_init(&vma->shared.vm_set.list);
205 else
206 vma_prio_tree_remove(vma, &mapping->i_mmap);
207 flush_dcache_mmap_unlock(mapping);
208}
209
210/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700211 * Unlink a file-based vm structure from its prio_tree, to hide
212 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700214void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215{
216 struct file *file = vma->vm_file;
217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 if (file) {
219 struct address_space *mapping = file->f_mapping;
220 spin_lock(&mapping->i_mmap_lock);
221 __remove_shared_vm_struct(vma, file, mapping);
222 spin_unlock(&mapping->i_mmap_lock);
223 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700224}
225
226/*
227 * Close a vm structure and free it, returning the next.
228 */
229static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
230{
231 struct vm_area_struct *next = vma->vm_next;
232
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700233 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 if (vma->vm_ops && vma->vm_ops->close)
235 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700236 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700237 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700238 if (vma->vm_flags & VM_EXECUTABLE)
239 removed_exe_file_vma(vma->vm_mm);
240 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700241 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700243 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246asmlinkage unsigned long sys_brk(unsigned long brk)
247{
248 unsigned long rlim, retval;
249 unsigned long newbrk, oldbrk;
250 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700251 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 down_write(&mm->mmap_sem);
254
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700255#ifdef CONFIG_COMPAT_BRK
256 min_brk = mm->end_code;
257#else
258 min_brk = mm->start_brk;
259#endif
260 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700262
263 /*
264 * Check against rlimit here. If this check is done later after the test
265 * of oldbrk with newbrk then it can escape the test and let the data
266 * segment grow beyond its set limit the in case where the limit is
267 * not page aligned -Ram Gupta
268 */
269 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100270 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
271 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700272 goto out;
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 newbrk = PAGE_ALIGN(brk);
275 oldbrk = PAGE_ALIGN(mm->brk);
276 if (oldbrk == newbrk)
277 goto set_brk;
278
279 /* Always allow shrinking brk. */
280 if (brk <= mm->brk) {
281 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
282 goto set_brk;
283 goto out;
284 }
285
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 /* Check against existing mmap mappings. */
287 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
288 goto out;
289
290 /* Ok, looks good - let it rip. */
291 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
292 goto out;
293set_brk:
294 mm->brk = brk;
295out:
296 retval = mm->brk;
297 up_write(&mm->mmap_sem);
298 return retval;
299}
300
301#ifdef DEBUG_MM_RB
302static int browse_rb(struct rb_root *root)
303{
304 int i = 0, j;
305 struct rb_node *nd, *pn = NULL;
306 unsigned long prev = 0, pend = 0;
307
308 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
309 struct vm_area_struct *vma;
310 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
311 if (vma->vm_start < prev)
312 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
313 if (vma->vm_start < pend)
314 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
315 if (vma->vm_start > vma->vm_end)
316 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
317 i++;
318 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800319 prev = vma->vm_start;
320 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 }
322 j = 0;
323 for (nd = pn; nd; nd = rb_prev(nd)) {
324 j++;
325 }
326 if (i != j)
327 printk("backwards %d, forwards %d\n", j, i), i = 0;
328 return i;
329}
330
331void validate_mm(struct mm_struct *mm)
332{
333 int bug = 0;
334 int i = 0;
335 struct vm_area_struct *tmp = mm->mmap;
336 while (tmp) {
337 tmp = tmp->vm_next;
338 i++;
339 }
340 if (i != mm->map_count)
341 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
342 i = browse_rb(&mm->mm_rb);
343 if (i != mm->map_count)
344 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200345 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347#else
348#define validate_mm(mm) do { } while (0)
349#endif
350
351static struct vm_area_struct *
352find_vma_prepare(struct mm_struct *mm, unsigned long addr,
353 struct vm_area_struct **pprev, struct rb_node ***rb_link,
354 struct rb_node ** rb_parent)
355{
356 struct vm_area_struct * vma;
357 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
358
359 __rb_link = &mm->mm_rb.rb_node;
360 rb_prev = __rb_parent = NULL;
361 vma = NULL;
362
363 while (*__rb_link) {
364 struct vm_area_struct *vma_tmp;
365
366 __rb_parent = *__rb_link;
367 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
368
369 if (vma_tmp->vm_end > addr) {
370 vma = vma_tmp;
371 if (vma_tmp->vm_start <= addr)
372 return vma;
373 __rb_link = &__rb_parent->rb_left;
374 } else {
375 rb_prev = __rb_parent;
376 __rb_link = &__rb_parent->rb_right;
377 }
378 }
379
380 *pprev = NULL;
381 if (rb_prev)
382 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
383 *rb_link = __rb_link;
384 *rb_parent = __rb_parent;
385 return vma;
386}
387
388static inline void
389__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
390 struct vm_area_struct *prev, struct rb_node *rb_parent)
391{
392 if (prev) {
393 vma->vm_next = prev->vm_next;
394 prev->vm_next = vma;
395 } else {
396 mm->mmap = vma;
397 if (rb_parent)
398 vma->vm_next = rb_entry(rb_parent,
399 struct vm_area_struct, vm_rb);
400 else
401 vma->vm_next = NULL;
402 }
403}
404
405void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
406 struct rb_node **rb_link, struct rb_node *rb_parent)
407{
408 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
409 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
410}
411
412static inline void __vma_link_file(struct vm_area_struct *vma)
413{
414 struct file * file;
415
416 file = vma->vm_file;
417 if (file) {
418 struct address_space *mapping = file->f_mapping;
419
420 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800421 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 if (vma->vm_flags & VM_SHARED)
423 mapping->i_mmap_writable++;
424
425 flush_dcache_mmap_lock(mapping);
426 if (unlikely(vma->vm_flags & VM_NONLINEAR))
427 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
428 else
429 vma_prio_tree_insert(vma, &mapping->i_mmap);
430 flush_dcache_mmap_unlock(mapping);
431 }
432}
433
434static void
435__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
436 struct vm_area_struct *prev, struct rb_node **rb_link,
437 struct rb_node *rb_parent)
438{
439 __vma_link_list(mm, vma, prev, rb_parent);
440 __vma_link_rb(mm, vma, rb_link, rb_parent);
441 __anon_vma_link(vma);
442}
443
444static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
445 struct vm_area_struct *prev, struct rb_node **rb_link,
446 struct rb_node *rb_parent)
447{
448 struct address_space *mapping = NULL;
449
450 if (vma->vm_file)
451 mapping = vma->vm_file->f_mapping;
452
453 if (mapping) {
454 spin_lock(&mapping->i_mmap_lock);
455 vma->vm_truncate_count = mapping->truncate_count;
456 }
457 anon_vma_lock(vma);
458
459 __vma_link(mm, vma, prev, rb_link, rb_parent);
460 __vma_link_file(vma);
461
462 anon_vma_unlock(vma);
463 if (mapping)
464 spin_unlock(&mapping->i_mmap_lock);
465
466 mm->map_count++;
467 validate_mm(mm);
468}
469
470/*
471 * Helper for vma_adjust in the split_vma insert case:
472 * insert vm structure into list and rbtree and anon_vma,
473 * but it has already been inserted into prio_tree earlier.
474 */
475static void
476__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
477{
478 struct vm_area_struct * __vma, * prev;
479 struct rb_node ** rb_link, * rb_parent;
480
481 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200482 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 __vma_link(mm, vma, prev, rb_link, rb_parent);
484 mm->map_count++;
485}
486
487static inline void
488__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
489 struct vm_area_struct *prev)
490{
491 prev->vm_next = vma->vm_next;
492 rb_erase(&vma->vm_rb, &mm->mm_rb);
493 if (mm->mmap_cache == vma)
494 mm->mmap_cache = prev;
495}
496
497/*
498 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
499 * is already present in an i_mmap tree without adjusting the tree.
500 * The following helper function should be used when such adjustments
501 * are necessary. The "insert" vma (if any) is to be inserted
502 * before we drop the necessary locks.
503 */
504void vma_adjust(struct vm_area_struct *vma, unsigned long start,
505 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
506{
507 struct mm_struct *mm = vma->vm_mm;
508 struct vm_area_struct *next = vma->vm_next;
509 struct vm_area_struct *importer = NULL;
510 struct address_space *mapping = NULL;
511 struct prio_tree_root *root = NULL;
512 struct file *file = vma->vm_file;
513 struct anon_vma *anon_vma = NULL;
514 long adjust_next = 0;
515 int remove_next = 0;
516
517 if (next && !insert) {
518 if (end >= next->vm_end) {
519 /*
520 * vma expands, overlapping all the next, and
521 * perhaps the one after too (mprotect case 6).
522 */
523again: remove_next = 1 + (end > next->vm_end);
524 end = next->vm_end;
525 anon_vma = next->anon_vma;
526 importer = vma;
527 } else if (end > next->vm_start) {
528 /*
529 * vma expands, overlapping part of the next:
530 * mprotect case 5 shifting the boundary up.
531 */
532 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
533 anon_vma = next->anon_vma;
534 importer = vma;
535 } else if (end < vma->vm_end) {
536 /*
537 * vma shrinks, and !insert tells it's not
538 * split_vma inserting another: so it must be
539 * mprotect case 4 shifting the boundary down.
540 */
541 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
542 anon_vma = next->anon_vma;
543 importer = next;
544 }
545 }
546
547 if (file) {
548 mapping = file->f_mapping;
549 if (!(vma->vm_flags & VM_NONLINEAR))
550 root = &mapping->i_mmap;
551 spin_lock(&mapping->i_mmap_lock);
552 if (importer &&
553 vma->vm_truncate_count != next->vm_truncate_count) {
554 /*
555 * unmap_mapping_range might be in progress:
556 * ensure that the expanding vma is rescanned.
557 */
558 importer->vm_truncate_count = 0;
559 }
560 if (insert) {
561 insert->vm_truncate_count = vma->vm_truncate_count;
562 /*
563 * Put into prio_tree now, so instantiated pages
564 * are visible to arm/parisc __flush_dcache_page
565 * throughout; but we cannot insert into address
566 * space until vma start or end is updated.
567 */
568 __vma_link_file(insert);
569 }
570 }
571
572 /*
573 * When changing only vma->vm_end, we don't really need
574 * anon_vma lock: but is that case worth optimizing out?
575 */
576 if (vma->anon_vma)
577 anon_vma = vma->anon_vma;
578 if (anon_vma) {
579 spin_lock(&anon_vma->lock);
580 /*
581 * Easily overlooked: when mprotect shifts the boundary,
582 * make sure the expanding vma has anon_vma set if the
583 * shrinking vma had, to cover any anon pages imported.
584 */
585 if (importer && !importer->anon_vma) {
586 importer->anon_vma = anon_vma;
587 __anon_vma_link(importer);
588 }
589 }
590
591 if (root) {
592 flush_dcache_mmap_lock(mapping);
593 vma_prio_tree_remove(vma, root);
594 if (adjust_next)
595 vma_prio_tree_remove(next, root);
596 }
597
598 vma->vm_start = start;
599 vma->vm_end = end;
600 vma->vm_pgoff = pgoff;
601 if (adjust_next) {
602 next->vm_start += adjust_next << PAGE_SHIFT;
603 next->vm_pgoff += adjust_next;
604 }
605
606 if (root) {
607 if (adjust_next)
608 vma_prio_tree_insert(next, root);
609 vma_prio_tree_insert(vma, root);
610 flush_dcache_mmap_unlock(mapping);
611 }
612
613 if (remove_next) {
614 /*
615 * vma_merge has merged next into vma, and needs
616 * us to remove next before dropping the locks.
617 */
618 __vma_unlink(mm, next, vma);
619 if (file)
620 __remove_shared_vm_struct(next, file, mapping);
621 if (next->anon_vma)
622 __anon_vma_merge(vma, next);
623 } else if (insert) {
624 /*
625 * split_vma has split insert from vma, and needs
626 * us to insert it before dropping the locks
627 * (it may either follow vma or precede it).
628 */
629 __insert_vm_struct(mm, insert);
630 }
631
632 if (anon_vma)
633 spin_unlock(&anon_vma->lock);
634 if (mapping)
635 spin_unlock(&mapping->i_mmap_lock);
636
637 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700638 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700640 if (next->vm_flags & VM_EXECUTABLE)
641 removed_exe_file_vma(mm);
642 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700644 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 kmem_cache_free(vm_area_cachep, next);
646 /*
647 * In mprotect's case 6 (see comments on vma_merge),
648 * we must remove another next too. It would clutter
649 * up the code too much to do both in one go.
650 */
651 if (remove_next == 2) {
652 next = vma->vm_next;
653 goto again;
654 }
655 }
656
657 validate_mm(mm);
658}
659
660/*
661 * If the vma has a ->close operation then the driver probably needs to release
662 * per-vma resources, so we don't attempt to merge those.
663 */
Hugh Dickinsa6f563d2006-03-22 00:08:29 -0800664#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
666static inline int is_mergeable_vma(struct vm_area_struct *vma,
667 struct file *file, unsigned long vm_flags)
668{
669 if (vma->vm_flags != vm_flags)
670 return 0;
671 if (vma->vm_file != file)
672 return 0;
673 if (vma->vm_ops && vma->vm_ops->close)
674 return 0;
675 return 1;
676}
677
678static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
679 struct anon_vma *anon_vma2)
680{
681 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
682}
683
684/*
685 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
686 * in front of (at a lower virtual address and file offset than) the vma.
687 *
688 * We cannot merge two vmas if they have differently assigned (non-NULL)
689 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
690 *
691 * We don't check here for the merged mmap wrapping around the end of pagecache
692 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
693 * wrap, nor mmaps which cover the final page at index -1UL.
694 */
695static int
696can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
697 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
698{
699 if (is_mergeable_vma(vma, file, vm_flags) &&
700 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
701 if (vma->vm_pgoff == vm_pgoff)
702 return 1;
703 }
704 return 0;
705}
706
707/*
708 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
709 * beyond (at a higher virtual address and file offset than) the vma.
710 *
711 * We cannot merge two vmas if they have differently assigned (non-NULL)
712 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
713 */
714static int
715can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
716 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
717{
718 if (is_mergeable_vma(vma, file, vm_flags) &&
719 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
720 pgoff_t vm_pglen;
721 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
722 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
723 return 1;
724 }
725 return 0;
726}
727
728/*
729 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
730 * whether that can be merged with its predecessor or its successor.
731 * Or both (it neatly fills a hole).
732 *
733 * In most cases - when called for mmap, brk or mremap - [addr,end) is
734 * certain not to be mapped by the time vma_merge is called; but when
735 * called for mprotect, it is certain to be already mapped (either at
736 * an offset within prev, or at the start of next), and the flags of
737 * this area are about to be changed to vm_flags - and the no-change
738 * case has already been eliminated.
739 *
740 * The following mprotect cases have to be considered, where AAAA is
741 * the area passed down from mprotect_fixup, never extending beyond one
742 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
743 *
744 * AAAA AAAA AAAA AAAA
745 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
746 * cannot merge might become might become might become
747 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
748 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
749 * mremap move: PPPPNNNNNNNN 8
750 * AAAA
751 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
752 * might become case 1 below case 2 below case 3 below
753 *
754 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
755 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
756 */
757struct vm_area_struct *vma_merge(struct mm_struct *mm,
758 struct vm_area_struct *prev, unsigned long addr,
759 unsigned long end, unsigned long vm_flags,
760 struct anon_vma *anon_vma, struct file *file,
761 pgoff_t pgoff, struct mempolicy *policy)
762{
763 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
764 struct vm_area_struct *area, *next;
765
766 /*
767 * We later require that vma->vm_flags == vm_flags,
768 * so this tests vma->vm_flags & VM_SPECIAL, too.
769 */
770 if (vm_flags & VM_SPECIAL)
771 return NULL;
772
773 if (prev)
774 next = prev->vm_next;
775 else
776 next = mm->mmap;
777 area = next;
778 if (next && next->vm_end == end) /* cases 6, 7, 8 */
779 next = next->vm_next;
780
781 /*
782 * Can it merge with the predecessor?
783 */
784 if (prev && prev->vm_end == addr &&
785 mpol_equal(vma_policy(prev), policy) &&
786 can_vma_merge_after(prev, vm_flags,
787 anon_vma, file, pgoff)) {
788 /*
789 * OK, it can. Can we now merge in the successor as well?
790 */
791 if (next && end == next->vm_start &&
792 mpol_equal(policy, vma_policy(next)) &&
793 can_vma_merge_before(next, vm_flags,
794 anon_vma, file, pgoff+pglen) &&
795 is_mergeable_anon_vma(prev->anon_vma,
796 next->anon_vma)) {
797 /* cases 1, 6 */
798 vma_adjust(prev, prev->vm_start,
799 next->vm_end, prev->vm_pgoff, NULL);
800 } else /* cases 2, 5, 7 */
801 vma_adjust(prev, prev->vm_start,
802 end, prev->vm_pgoff, NULL);
803 return prev;
804 }
805
806 /*
807 * Can this new request be merged in front of next?
808 */
809 if (next && end == next->vm_start &&
810 mpol_equal(policy, vma_policy(next)) &&
811 can_vma_merge_before(next, vm_flags,
812 anon_vma, file, pgoff+pglen)) {
813 if (prev && addr < prev->vm_end) /* case 4 */
814 vma_adjust(prev, prev->vm_start,
815 addr, prev->vm_pgoff, NULL);
816 else /* cases 3, 8 */
817 vma_adjust(area, addr, next->vm_end,
818 next->vm_pgoff - pglen, NULL);
819 return area;
820 }
821
822 return NULL;
823}
824
825/*
826 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
827 * neighbouring vmas for a suitable anon_vma, before it goes off
828 * to allocate a new anon_vma. It checks because a repetitive
829 * sequence of mprotects and faults may otherwise lead to distinct
830 * anon_vmas being allocated, preventing vma merge in subsequent
831 * mprotect.
832 */
833struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
834{
835 struct vm_area_struct *near;
836 unsigned long vm_flags;
837
838 near = vma->vm_next;
839 if (!near)
840 goto try_prev;
841
842 /*
843 * Since only mprotect tries to remerge vmas, match flags
844 * which might be mprotected into each other later on.
845 * Neither mlock nor madvise tries to remerge at present,
846 * so leave their flags as obstructing a merge.
847 */
848 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
849 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
850
851 if (near->anon_vma && vma->vm_end == near->vm_start &&
852 mpol_equal(vma_policy(vma), vma_policy(near)) &&
853 can_vma_merge_before(near, vm_flags,
854 NULL, vma->vm_file, vma->vm_pgoff +
855 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
856 return near->anon_vma;
857try_prev:
858 /*
859 * It is potentially slow to have to call find_vma_prev here.
860 * But it's only on the first write fault on the vma, not
861 * every time, and we could devise a way to avoid it later
862 * (e.g. stash info in next's anon_vma_node when assigning
863 * an anon_vma, or when trying vma_merge). Another time.
864 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200865 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 if (!near)
867 goto none;
868
869 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
870 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
871
872 if (near->anon_vma && near->vm_end == vma->vm_start &&
873 mpol_equal(vma_policy(near), vma_policy(vma)) &&
874 can_vma_merge_after(near, vm_flags,
875 NULL, vma->vm_file, vma->vm_pgoff))
876 return near->anon_vma;
877none:
878 /*
879 * There's no absolute need to look only at touching neighbours:
880 * we could search further afield for "compatible" anon_vmas.
881 * But it would probably just be a waste of time searching,
882 * or lead to too many vmas hanging off the same anon_vma.
883 * We're trying to allow mprotect remerging later on,
884 * not trying to minimize memory used for anon_vmas.
885 */
886 return NULL;
887}
888
889#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700890void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 struct file *file, long pages)
892{
893 const unsigned long stack_flags
894 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
895
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 if (file) {
897 mm->shared_vm += pages;
898 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
899 mm->exec_vm += pages;
900 } else if (flags & stack_flags)
901 mm->stack_vm += pages;
902 if (flags & (VM_RESERVED|VM_IO))
903 mm->reserved_vm += pages;
904}
905#endif /* CONFIG_PROC_FS */
906
907/*
908 * The caller must hold down_write(current->mm->mmap_sem).
909 */
910
911unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
912 unsigned long len, unsigned long prot,
913 unsigned long flags, unsigned long pgoff)
914{
915 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 struct inode *inode;
917 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 int accountable = 1;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700920 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 /*
923 * Does the application expect PROT_READ to imply PROT_EXEC?
924 *
925 * (the exception is when the underlying filesystem is noexec
926 * mounted, in which case we dont add PROT_EXEC.)
927 */
928 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800929 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 prot |= PROT_EXEC;
931
932 if (!len)
933 return -EINVAL;
934
Eric Paris7cd94142007-11-26 18:47:40 -0500935 if (!(flags & MAP_FIXED))
936 addr = round_hint_to_min(addr);
937
Kirill Korotaev3a459752006-09-07 14:17:04 +0400938 error = arch_mmap_check(addr, len, flags);
939 if (error)
940 return error;
941
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 /* Careful about overflows.. */
943 len = PAGE_ALIGN(len);
944 if (!len || len > TASK_SIZE)
945 return -ENOMEM;
946
947 /* offset overflow? */
948 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
949 return -EOVERFLOW;
950
951 /* Too many mappings? */
952 if (mm->map_count > sysctl_max_map_count)
953 return -ENOMEM;
954
955 /* Obtain the address to map to. we verify (or select) it and ensure
956 * that it represents a valid section of the address space.
957 */
958 addr = get_unmapped_area(file, addr, len, pgoff, flags);
959 if (addr & ~PAGE_MASK)
960 return addr;
961
962 /* Do simple checking here so the lower-level routines won't have
963 * to. we assume access permissions have been handled by the open
964 * of the memory object, so we don't do any here.
965 */
966 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
967 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
968
969 if (flags & MAP_LOCKED) {
970 if (!can_do_mlock())
971 return -EPERM;
972 vm_flags |= VM_LOCKED;
973 }
974 /* mlock MCL_FUTURE? */
975 if (vm_flags & VM_LOCKED) {
976 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700977 locked = len >> PAGE_SHIFT;
978 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700980 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
982 return -EAGAIN;
983 }
984
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800985 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
987 if (file) {
988 switch (flags & MAP_TYPE) {
989 case MAP_SHARED:
990 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
991 return -EACCES;
992
993 /*
994 * Make sure we don't allow writing to an append-only
995 * file..
996 */
997 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
998 return -EACCES;
999
1000 /*
1001 * Make sure there are no mandatory locks on the file.
1002 */
1003 if (locks_verify_locked(inode))
1004 return -EAGAIN;
1005
1006 vm_flags |= VM_SHARED | VM_MAYSHARE;
1007 if (!(file->f_mode & FMODE_WRITE))
1008 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1009
1010 /* fall through */
1011 case MAP_PRIVATE:
1012 if (!(file->f_mode & FMODE_READ))
1013 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001014 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001015 if (vm_flags & VM_EXEC)
1016 return -EPERM;
1017 vm_flags &= ~VM_MAYEXEC;
1018 }
1019 if (is_file_hugepages(file))
1020 accountable = 0;
1021
1022 if (!file->f_op || !file->f_op->mmap)
1023 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 break;
1025
1026 default:
1027 return -EINVAL;
1028 }
1029 } else {
1030 switch (flags & MAP_TYPE) {
1031 case MAP_SHARED:
1032 vm_flags |= VM_SHARED | VM_MAYSHARE;
1033 break;
1034 case MAP_PRIVATE:
1035 /*
1036 * Set pgoff according to addr for anon_vma.
1037 */
1038 pgoff = addr >> PAGE_SHIFT;
1039 break;
1040 default:
1041 return -EINVAL;
1042 }
1043 }
1044
Eric Parised032182007-06-28 15:55:21 -04001045 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 if (error)
1047 return error;
Eric Parised032182007-06-28 15:55:21 -04001048
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001049 return mmap_region(file, addr, len, flags, vm_flags, pgoff,
1050 accountable);
1051}
1052EXPORT_SYMBOL(do_mmap_pgoff);
1053
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001054/*
1055 * Some shared mappigns will want the pages marked read-only
1056 * to track write events. If so, we'll downgrade vm_page_prot
1057 * to the private version (using protection_map[] without the
1058 * VM_SHARED bit).
1059 */
1060int vma_wants_writenotify(struct vm_area_struct *vma)
1061{
1062 unsigned int vm_flags = vma->vm_flags;
1063
1064 /* If it was private or non-writable, the write bit is already clear */
1065 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1066 return 0;
1067
1068 /* The backer wishes to know when pages are first written to? */
1069 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1070 return 1;
1071
1072 /* The open routine did something to the protections already? */
1073 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001074 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001075 return 0;
1076
1077 /* Specialty mapping? */
1078 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1079 return 0;
1080
1081 /* Can the mapping track the dirty pages? */
1082 return vma->vm_file && vma->vm_file->f_mapping &&
1083 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1084}
1085
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001086unsigned long mmap_region(struct file *file, unsigned long addr,
1087 unsigned long len, unsigned long flags,
1088 unsigned int vm_flags, unsigned long pgoff,
1089 int accountable)
1090{
1091 struct mm_struct *mm = current->mm;
1092 struct vm_area_struct *vma, *prev;
1093 int correct_wcount = 0;
1094 int error;
1095 struct rb_node **rb_link, *rb_parent;
1096 unsigned long charged = 0;
1097 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1098
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 /* Clear old maps */
1100 error = -ENOMEM;
1101munmap_back:
1102 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1103 if (vma && vma->vm_start < addr + len) {
1104 if (do_munmap(mm, addr, len))
1105 return -ENOMEM;
1106 goto munmap_back;
1107 }
1108
1109 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001110 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 return -ENOMEM;
1112
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001113 if (flags & MAP_NORESERVE)
1114 vm_flags |= VM_NORESERVE;
1115
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 if (accountable && (!(flags & MAP_NORESERVE) ||
1117 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1118 if (vm_flags & VM_SHARED) {
1119 /* Check memory availability in shmem_file_setup? */
1120 vm_flags |= VM_ACCOUNT;
1121 } else if (vm_flags & VM_WRITE) {
1122 /*
1123 * Private writable mapping: check memory availability
1124 */
1125 charged = len >> PAGE_SHIFT;
1126 if (security_vm_enough_memory(charged))
1127 return -ENOMEM;
1128 vm_flags |= VM_ACCOUNT;
1129 }
1130 }
1131
1132 /*
1133 * Can we just expand an old private anonymous mapping?
1134 * The VM_SHARED test is necessary because shmem_zero_setup
1135 * will create the file object for a shared anonymous map below.
1136 */
1137 if (!file && !(vm_flags & VM_SHARED) &&
1138 vma_merge(mm, prev, addr, addr + len, vm_flags,
1139 NULL, NULL, pgoff, NULL))
1140 goto out;
1141
1142 /*
1143 * Determine the object being mapped and call the appropriate
1144 * specific mapper. the address has already been validated, but
1145 * not unmapped, but the maps are removed from the list.
1146 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001147 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 if (!vma) {
1149 error = -ENOMEM;
1150 goto unacct_error;
1151 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152
1153 vma->vm_mm = mm;
1154 vma->vm_start = addr;
1155 vma->vm_end = addr + len;
1156 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001157 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 vma->vm_pgoff = pgoff;
1159
1160 if (file) {
1161 error = -EINVAL;
1162 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1163 goto free_vma;
1164 if (vm_flags & VM_DENYWRITE) {
1165 error = deny_write_access(file);
1166 if (error)
1167 goto free_vma;
1168 correct_wcount = 1;
1169 }
1170 vma->vm_file = file;
1171 get_file(file);
1172 error = file->f_op->mmap(file, vma);
1173 if (error)
1174 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001175 if (vm_flags & VM_EXECUTABLE)
1176 added_exe_file_vma(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 } else if (vm_flags & VM_SHARED) {
1178 error = shmem_zero_setup(vma);
1179 if (error)
1180 goto free_vma;
1181 }
1182
1183 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1184 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1185 * that memory reservation must be checked; but that reservation
1186 * belongs to shared memory object, not to vma: so now clear it.
1187 */
1188 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1189 vma->vm_flags &= ~VM_ACCOUNT;
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;
1199
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001200 if (vma_wants_writenotify(vma))
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001201 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001202
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001203 if (file && vma_merge(mm, prev, addr, vma->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
Lee Schermerhornf0be3d32008-04-28 02:13:08 -07001205 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 kmem_cache_free(vm_area_cachep, vma);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001207 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001208 if (vm_flags & VM_EXECUTABLE)
1209 removed_exe_file_vma(mm);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001210 } else {
1211 vma_link(mm, vma, prev, rb_link, rb_parent);
1212 file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 }
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001214
1215 /* Once vma denies write, undo our temporary denial count */
1216 if (correct_wcount)
1217 atomic_inc(&inode->i_writecount);
1218out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001220 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 if (vm_flags & VM_LOCKED) {
1222 mm->locked_vm += len >> PAGE_SHIFT;
1223 make_pages_present(addr, addr + len);
1224 }
Nick Piggin54cb8822007-07-19 01:46:59 -07001225 if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1226 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 return addr;
1228
1229unmap_and_free_vma:
1230 if (correct_wcount)
1231 atomic_inc(&inode->i_writecount);
1232 vma->vm_file = NULL;
1233 fput(file);
1234
1235 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001236 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1237 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238free_vma:
1239 kmem_cache_free(vm_area_cachep, vma);
1240unacct_error:
1241 if (charged)
1242 vm_unacct_memory(charged);
1243 return error;
1244}
1245
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246/* Get an address range which is currently unmapped.
1247 * For shmat() with addr=0.
1248 *
1249 * Ugly calling convention alert:
1250 * Return value with the low bits set means error value,
1251 * ie
1252 * if (ret & ~PAGE_MASK)
1253 * error = ret;
1254 *
1255 * This function "knows" that -ENOMEM has the bits set.
1256 */
1257#ifndef HAVE_ARCH_UNMAPPED_AREA
1258unsigned long
1259arch_get_unmapped_area(struct file *filp, unsigned long addr,
1260 unsigned long len, unsigned long pgoff, unsigned long flags)
1261{
1262 struct mm_struct *mm = current->mm;
1263 struct vm_area_struct *vma;
1264 unsigned long start_addr;
1265
1266 if (len > TASK_SIZE)
1267 return -ENOMEM;
1268
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001269 if (flags & MAP_FIXED)
1270 return addr;
1271
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 if (addr) {
1273 addr = PAGE_ALIGN(addr);
1274 vma = find_vma(mm, addr);
1275 if (TASK_SIZE - len >= addr &&
1276 (!vma || addr + len <= vma->vm_start))
1277 return addr;
1278 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001279 if (len > mm->cached_hole_size) {
1280 start_addr = addr = mm->free_area_cache;
1281 } else {
1282 start_addr = addr = TASK_UNMAPPED_BASE;
1283 mm->cached_hole_size = 0;
1284 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285
1286full_search:
1287 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1288 /* At this point: (!vma || addr < vma->vm_end). */
1289 if (TASK_SIZE - len < addr) {
1290 /*
1291 * Start a new search - just in case we missed
1292 * some holes.
1293 */
1294 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001295 addr = TASK_UNMAPPED_BASE;
1296 start_addr = addr;
1297 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 goto full_search;
1299 }
1300 return -ENOMEM;
1301 }
1302 if (!vma || addr + len <= vma->vm_start) {
1303 /*
1304 * Remember the place where we stopped the search:
1305 */
1306 mm->free_area_cache = addr + len;
1307 return addr;
1308 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001309 if (addr + mm->cached_hole_size < vma->vm_start)
1310 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 addr = vma->vm_end;
1312 }
1313}
1314#endif
1315
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001316void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317{
1318 /*
1319 * Is this a new hole at the lowest possible address?
1320 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001321 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1322 mm->free_area_cache = addr;
1323 mm->cached_hole_size = ~0UL;
1324 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325}
1326
1327/*
1328 * This mmap-allocator allocates new areas top-down from below the
1329 * stack's low limit (the base):
1330 */
1331#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1332unsigned long
1333arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1334 const unsigned long len, const unsigned long pgoff,
1335 const unsigned long flags)
1336{
1337 struct vm_area_struct *vma;
1338 struct mm_struct *mm = current->mm;
1339 unsigned long addr = addr0;
1340
1341 /* requested length too big for entire address space */
1342 if (len > TASK_SIZE)
1343 return -ENOMEM;
1344
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001345 if (flags & MAP_FIXED)
1346 return addr;
1347
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 /* requesting a specific address */
1349 if (addr) {
1350 addr = PAGE_ALIGN(addr);
1351 vma = find_vma(mm, addr);
1352 if (TASK_SIZE - len >= addr &&
1353 (!vma || addr + len <= vma->vm_start))
1354 return addr;
1355 }
1356
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001357 /* check if free_area_cache is useful for us */
1358 if (len <= mm->cached_hole_size) {
1359 mm->cached_hole_size = 0;
1360 mm->free_area_cache = mm->mmap_base;
1361 }
1362
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363 /* either no address requested or can't fit in requested address hole */
1364 addr = mm->free_area_cache;
1365
1366 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001367 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 vma = find_vma(mm, addr-len);
1369 if (!vma || addr <= vma->vm_start)
1370 /* remember the address as a hint for next time */
1371 return (mm->free_area_cache = addr-len);
1372 }
1373
Chris Wright73219d12005-06-21 17:14:52 -07001374 if (mm->mmap_base < len)
1375 goto bottomup;
1376
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 addr = mm->mmap_base-len;
1378
1379 do {
1380 /*
1381 * Lookup failure means no vma is above this address,
1382 * else if new region fits below vma->vm_start,
1383 * return with success:
1384 */
1385 vma = find_vma(mm, addr);
1386 if (!vma || addr+len <= vma->vm_start)
1387 /* remember the address as a hint for next time */
1388 return (mm->free_area_cache = addr);
1389
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001390 /* remember the largest hole we saw so far */
1391 if (addr + mm->cached_hole_size < vma->vm_start)
1392 mm->cached_hole_size = vma->vm_start - addr;
1393
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 /* try just below the current vma->vm_start */
1395 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001396 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397
Chris Wright73219d12005-06-21 17:14:52 -07001398bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 /*
1400 * A failed mmap() very likely causes application failure,
1401 * so fall back to the bottom-up function here. This scenario
1402 * can happen with large stack limits and large mmap()
1403 * allocations.
1404 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001405 mm->cached_hole_size = ~0UL;
1406 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1408 /*
1409 * Restore the topdown base:
1410 */
1411 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001412 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
1414 return addr;
1415}
1416#endif
1417
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001418void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419{
1420 /*
1421 * Is this a new hole at the highest possible address?
1422 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001423 if (addr > mm->free_area_cache)
1424 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425
1426 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001427 if (mm->free_area_cache > mm->mmap_base)
1428 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429}
1430
1431unsigned long
1432get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1433 unsigned long pgoff, unsigned long flags)
1434{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001435 unsigned long (*get_area)(struct file *, unsigned long,
1436 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001438 get_area = current->mm->get_unmapped_area;
1439 if (file && file->f_op && file->f_op->get_unmapped_area)
1440 get_area = file->f_op->get_unmapped_area;
1441 addr = get_area(file, addr, len, pgoff, flags);
1442 if (IS_ERR_VALUE(addr))
1443 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001445 if (addr > TASK_SIZE - len)
1446 return -ENOMEM;
1447 if (addr & ~PAGE_MASK)
1448 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001449
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001450 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451}
1452
1453EXPORT_SYMBOL(get_unmapped_area);
1454
1455/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1456struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1457{
1458 struct vm_area_struct *vma = NULL;
1459
1460 if (mm) {
1461 /* Check the cache first. */
1462 /* (Cache hit rate is typically around 35%.) */
1463 vma = mm->mmap_cache;
1464 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1465 struct rb_node * rb_node;
1466
1467 rb_node = mm->mm_rb.rb_node;
1468 vma = NULL;
1469
1470 while (rb_node) {
1471 struct vm_area_struct * vma_tmp;
1472
1473 vma_tmp = rb_entry(rb_node,
1474 struct vm_area_struct, vm_rb);
1475
1476 if (vma_tmp->vm_end > addr) {
1477 vma = vma_tmp;
1478 if (vma_tmp->vm_start <= addr)
1479 break;
1480 rb_node = rb_node->rb_left;
1481 } else
1482 rb_node = rb_node->rb_right;
1483 }
1484 if (vma)
1485 mm->mmap_cache = vma;
1486 }
1487 }
1488 return vma;
1489}
1490
1491EXPORT_SYMBOL(find_vma);
1492
1493/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1494struct vm_area_struct *
1495find_vma_prev(struct mm_struct *mm, unsigned long addr,
1496 struct vm_area_struct **pprev)
1497{
1498 struct vm_area_struct *vma = NULL, *prev = NULL;
1499 struct rb_node * rb_node;
1500 if (!mm)
1501 goto out;
1502
1503 /* Guard against addr being lower than the first VMA */
1504 vma = mm->mmap;
1505
1506 /* Go through the RB tree quickly. */
1507 rb_node = mm->mm_rb.rb_node;
1508
1509 while (rb_node) {
1510 struct vm_area_struct *vma_tmp;
1511 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1512
1513 if (addr < vma_tmp->vm_end) {
1514 rb_node = rb_node->rb_left;
1515 } else {
1516 prev = vma_tmp;
1517 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1518 break;
1519 rb_node = rb_node->rb_right;
1520 }
1521 }
1522
1523out:
1524 *pprev = prev;
1525 return prev ? prev->vm_next : vma;
1526}
1527
1528/*
1529 * Verify that the stack growth is acceptable and
1530 * update accounting. This is shared with both the
1531 * grow-up and grow-down cases.
1532 */
1533static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1534{
1535 struct mm_struct *mm = vma->vm_mm;
1536 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001537 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538
1539 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001540 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 return -ENOMEM;
1542
1543 /* Stack limit test */
1544 if (size > rlim[RLIMIT_STACK].rlim_cur)
1545 return -ENOMEM;
1546
1547 /* mlock limit tests */
1548 if (vma->vm_flags & VM_LOCKED) {
1549 unsigned long locked;
1550 unsigned long limit;
1551 locked = mm->locked_vm + grow;
1552 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1553 if (locked > limit && !capable(CAP_IPC_LOCK))
1554 return -ENOMEM;
1555 }
1556
Adam Litke0d59a012007-01-30 14:35:39 -08001557 /* Check to ensure the stack will not grow into a hugetlb-only region */
1558 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1559 vma->vm_end - size;
1560 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1561 return -EFAULT;
1562
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563 /*
1564 * Overcommit.. This must be the final test, as it will
1565 * update security statistics.
1566 */
1567 if (security_vm_enough_memory(grow))
1568 return -ENOMEM;
1569
1570 /* Ok, everything looks good - let it rip */
1571 mm->total_vm += grow;
1572 if (vma->vm_flags & VM_LOCKED)
1573 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001574 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575 return 0;
1576}
1577
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001578#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001580 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1581 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001583#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001584static inline
1585#endif
1586int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587{
1588 int error;
1589
1590 if (!(vma->vm_flags & VM_GROWSUP))
1591 return -EFAULT;
1592
1593 /*
1594 * We must make sure the anon_vma is allocated
1595 * so that the anon_vma locking is not a noop.
1596 */
1597 if (unlikely(anon_vma_prepare(vma)))
1598 return -ENOMEM;
1599 anon_vma_lock(vma);
1600
1601 /*
1602 * vma->vm_start/vm_end cannot change under us because the caller
1603 * is required to hold the mmap_sem in read mode. We need the
1604 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001605 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 */
Helge Deller06b32f32006-12-19 19:28:33 +01001607 if (address < PAGE_ALIGN(address+4))
1608 address = PAGE_ALIGN(address+4);
1609 else {
1610 anon_vma_unlock(vma);
1611 return -ENOMEM;
1612 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613 error = 0;
1614
1615 /* Somebody else might have raced and expanded it already */
1616 if (address > vma->vm_end) {
1617 unsigned long size, grow;
1618
1619 size = address - vma->vm_start;
1620 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1621
1622 error = acct_stack_growth(vma, size, grow);
1623 if (!error)
1624 vma->vm_end = address;
1625 }
1626 anon_vma_unlock(vma);
1627 return error;
1628}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001629#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1630
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631/*
1632 * vma is the first one with address < vma->vm_start. Have to extend vma.
1633 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001634static inline int expand_downwards(struct vm_area_struct *vma,
1635 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636{
1637 int error;
1638
1639 /*
1640 * We must make sure the anon_vma is allocated
1641 * so that the anon_vma locking is not a noop.
1642 */
1643 if (unlikely(anon_vma_prepare(vma)))
1644 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001645
1646 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001647 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001648 if (error)
1649 return error;
1650
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651 anon_vma_lock(vma);
1652
1653 /*
1654 * vma->vm_start/vm_end cannot change under us because the caller
1655 * is required to hold the mmap_sem in read mode. We need the
1656 * anon_vma lock to serialize against concurrent expand_stacks.
1657 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658
1659 /* Somebody else might have raced and expanded it already */
1660 if (address < vma->vm_start) {
1661 unsigned long size, grow;
1662
1663 size = vma->vm_end - address;
1664 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1665
1666 error = acct_stack_growth(vma, size, grow);
1667 if (!error) {
1668 vma->vm_start = address;
1669 vma->vm_pgoff -= grow;
1670 }
1671 }
1672 anon_vma_unlock(vma);
1673 return error;
1674}
1675
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001676int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1677{
1678 return expand_downwards(vma, address);
1679}
1680
1681#ifdef CONFIG_STACK_GROWSUP
1682int expand_stack(struct vm_area_struct *vma, unsigned long address)
1683{
1684 return expand_upwards(vma, address);
1685}
1686
1687struct vm_area_struct *
1688find_extend_vma(struct mm_struct *mm, unsigned long addr)
1689{
1690 struct vm_area_struct *vma, *prev;
1691
1692 addr &= PAGE_MASK;
1693 vma = find_vma_prev(mm, addr, &prev);
1694 if (vma && (vma->vm_start <= addr))
1695 return vma;
1696 if (!prev || expand_stack(prev, addr))
1697 return NULL;
1698 if (prev->vm_flags & VM_LOCKED)
1699 make_pages_present(addr, prev->vm_end);
1700 return prev;
1701}
1702#else
1703int expand_stack(struct vm_area_struct *vma, unsigned long address)
1704{
1705 return expand_downwards(vma, address);
1706}
1707
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708struct vm_area_struct *
1709find_extend_vma(struct mm_struct * mm, unsigned long addr)
1710{
1711 struct vm_area_struct * vma;
1712 unsigned long start;
1713
1714 addr &= PAGE_MASK;
1715 vma = find_vma(mm,addr);
1716 if (!vma)
1717 return NULL;
1718 if (vma->vm_start <= addr)
1719 return vma;
1720 if (!(vma->vm_flags & VM_GROWSDOWN))
1721 return NULL;
1722 start = vma->vm_start;
1723 if (expand_stack(vma, addr))
1724 return NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001725 if (vma->vm_flags & VM_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 make_pages_present(addr, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727 return vma;
1728}
1729#endif
1730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001732 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001734 *
1735 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001737static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001739 /* Update high watermark before we lower total_vm */
1740 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001742 long nrpages = vma_pages(vma);
1743
1744 mm->total_vm -= nrpages;
1745 if (vma->vm_flags & VM_LOCKED)
1746 mm->locked_vm -= nrpages;
1747 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001748 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001749 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 validate_mm(mm);
1751}
1752
1753/*
1754 * Get rid of page table information in the indicated region.
1755 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001756 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 */
1758static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001759 struct vm_area_struct *vma, struct vm_area_struct *prev,
1760 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001762 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 struct mmu_gather *tlb;
1764 unsigned long nr_accounted = 0;
1765
1766 lru_add_drain();
1767 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001768 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001769 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07001771 free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001772 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 tlb_finish_mmu(tlb, start, end);
1774}
1775
1776/*
1777 * Create a list of vma's touched by the unmap, removing them from the mm's
1778 * vma list as we go..
1779 */
1780static void
1781detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1782 struct vm_area_struct *prev, unsigned long end)
1783{
1784 struct vm_area_struct **insertion_point;
1785 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001786 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
1788 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1789 do {
1790 rb_erase(&vma->vm_rb, &mm->mm_rb);
1791 mm->map_count--;
1792 tail_vma = vma;
1793 vma = vma->vm_next;
1794 } while (vma && vma->vm_start < end);
1795 *insertion_point = vma;
1796 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001797 if (mm->unmap_area == arch_unmap_area)
1798 addr = prev ? prev->vm_end : mm->mmap_base;
1799 else
1800 addr = vma ? vma->vm_start : mm->mmap_base;
1801 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 mm->mmap_cache = NULL; /* Kill the cache. */
1803}
1804
1805/*
1806 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001807 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 */
1809int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1810 unsigned long addr, int new_below)
1811{
1812 struct mempolicy *pol;
1813 struct vm_area_struct *new;
1814
Andi Kleena5516432008-07-23 21:27:41 -07001815 if (is_vm_hugetlb_page(vma) && (addr &
1816 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 return -EINVAL;
1818
1819 if (mm->map_count >= sysctl_max_map_count)
1820 return -ENOMEM;
1821
Christoph Lametere94b1762006-12-06 20:33:17 -08001822 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823 if (!new)
1824 return -ENOMEM;
1825
1826 /* most fields are the same, copy all, and then fixup */
1827 *new = *vma;
1828
1829 if (new_below)
1830 new->vm_end = addr;
1831 else {
1832 new->vm_start = addr;
1833 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1834 }
1835
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001836 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837 if (IS_ERR(pol)) {
1838 kmem_cache_free(vm_area_cachep, new);
1839 return PTR_ERR(pol);
1840 }
1841 vma_set_policy(new, pol);
1842
Matt Helsley925d1c42008-04-29 01:01:36 -07001843 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001845 if (vma->vm_flags & VM_EXECUTABLE)
1846 added_exe_file_vma(mm);
1847 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848
1849 if (new->vm_ops && new->vm_ops->open)
1850 new->vm_ops->open(new);
1851
1852 if (new_below)
1853 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1854 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1855 else
1856 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1857
1858 return 0;
1859}
1860
1861/* Munmap is split into 2 main parts -- this part which finds
1862 * what needs doing, and the areas themselves, which do the
1863 * work. This now handles partial unmappings.
1864 * Jeremy Fitzhardinge <jeremy@goop.org>
1865 */
1866int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1867{
1868 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001869 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870
1871 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1872 return -EINVAL;
1873
1874 if ((len = PAGE_ALIGN(len)) == 0)
1875 return -EINVAL;
1876
1877 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001878 vma = find_vma_prev(mm, start, &prev);
1879 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001881 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882
1883 /* if it doesn't overlap, we have nothing.. */
1884 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001885 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001886 return 0;
1887
1888 /*
1889 * If we need to split any vma, do it now to save pain later.
1890 *
1891 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1892 * unmapped vm_area_struct will remain in use: so lower split_vma
1893 * places tmp vma above, and higher split_vma places tmp vma below.
1894 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001895 if (start > vma->vm_start) {
1896 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 if (error)
1898 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001899 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 }
1901
1902 /* Does it split the last one? */
1903 last = find_vma(mm, end);
1904 if (last && end > last->vm_start) {
1905 int error = split_vma(mm, last, end, 1);
1906 if (error)
1907 return error;
1908 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001909 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910
1911 /*
1912 * Remove the vma's, and unmap the actual pages
1913 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001914 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1915 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916
1917 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001918 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919
1920 return 0;
1921}
1922
1923EXPORT_SYMBOL(do_munmap);
1924
1925asmlinkage long sys_munmap(unsigned long addr, size_t len)
1926{
1927 int ret;
1928 struct mm_struct *mm = current->mm;
1929
1930 profile_munmap(addr);
1931
1932 down_write(&mm->mmap_sem);
1933 ret = do_munmap(mm, addr, len);
1934 up_write(&mm->mmap_sem);
1935 return ret;
1936}
1937
1938static inline void verify_mm_writelocked(struct mm_struct *mm)
1939{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001940#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1942 WARN_ON(1);
1943 up_read(&mm->mmap_sem);
1944 }
1945#endif
1946}
1947
1948/*
1949 * this is really a simplified "do_mmap". it only handles
1950 * anonymous maps. eventually we may be able to do some
1951 * brk-specific accounting here.
1952 */
1953unsigned long do_brk(unsigned long addr, unsigned long len)
1954{
1955 struct mm_struct * mm = current->mm;
1956 struct vm_area_struct * vma, * prev;
1957 unsigned long flags;
1958 struct rb_node ** rb_link, * rb_parent;
1959 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001960 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961
1962 len = PAGE_ALIGN(len);
1963 if (!len)
1964 return addr;
1965
1966 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1967 return -EINVAL;
1968
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001969 if (is_hugepage_only_range(mm, addr, len))
1970 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001971
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001972 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05001973 if (error)
1974 return error;
1975
Kirill Korotaev3a459752006-09-07 14:17:04 +04001976 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1977
1978 error = arch_mmap_check(addr, len, flags);
1979 if (error)
1980 return error;
1981
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982 /*
1983 * mlock MCL_FUTURE?
1984 */
1985 if (mm->def_flags & VM_LOCKED) {
1986 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001987 locked = len >> PAGE_SHIFT;
1988 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001990 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1992 return -EAGAIN;
1993 }
1994
1995 /*
1996 * mm->mmap_sem is required to protect against another thread
1997 * changing the mappings in case we sleep.
1998 */
1999 verify_mm_writelocked(mm);
2000
2001 /*
2002 * Clear old maps. this also does some error checking for us
2003 */
2004 munmap_back:
2005 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2006 if (vma && vma->vm_start < addr + len) {
2007 if (do_munmap(mm, addr, len))
2008 return -ENOMEM;
2009 goto munmap_back;
2010 }
2011
2012 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002013 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014 return -ENOMEM;
2015
2016 if (mm->map_count > sysctl_max_map_count)
2017 return -ENOMEM;
2018
2019 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2020 return -ENOMEM;
2021
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022 /* Can we just expand an old private anonymous mapping? */
2023 if (vma_merge(mm, prev, addr, addr + len, flags,
2024 NULL, NULL, pgoff, NULL))
2025 goto out;
2026
2027 /*
2028 * create a vma struct for an anonymous mapping
2029 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002030 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002031 if (!vma) {
2032 vm_unacct_memory(len >> PAGE_SHIFT);
2033 return -ENOMEM;
2034 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035
2036 vma->vm_mm = mm;
2037 vma->vm_start = addr;
2038 vma->vm_end = addr + len;
2039 vma->vm_pgoff = pgoff;
2040 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002041 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042 vma_link(mm, vma, prev, rb_link, rb_parent);
2043out:
2044 mm->total_vm += len >> PAGE_SHIFT;
2045 if (flags & VM_LOCKED) {
2046 mm->locked_vm += len >> PAGE_SHIFT;
2047 make_pages_present(addr, addr + len);
2048 }
2049 return addr;
2050}
2051
2052EXPORT_SYMBOL(do_brk);
2053
2054/* Release all mmaps. */
2055void exit_mmap(struct mm_struct *mm)
2056{
2057 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07002058 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002059 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002060 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002062 /* mm's last user has gone, and its about to be pulled down */
2063 arch_exit_mmap(mm);
2064
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002067 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002068 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002069 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002070 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002071 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07002072 free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002073 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074
Linus Torvalds1da177e2005-04-16 15:20:36 -07002075 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002076 * Walk the list again, actually closing and freeing it,
2077 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002078 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002079 while (vma)
2080 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002081
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002082 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083}
2084
2085/* Insert vm structure into process list sorted by address
2086 * and into the inode's i_mmap tree. If vm_file is non-NULL
2087 * then i_mmap_lock is taken here.
2088 */
2089int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2090{
2091 struct vm_area_struct * __vma, * prev;
2092 struct rb_node ** rb_link, * rb_parent;
2093
2094 /*
2095 * The vm_pgoff of a purely anonymous vma should be irrelevant
2096 * until its first write fault, when page's anon_vma and index
2097 * are set. But now set the vm_pgoff it will almost certainly
2098 * end up with (unless mremap moves it elsewhere before that
2099 * first wfault), so /proc/pid/maps tells a consistent story.
2100 *
2101 * By setting it to reflect the virtual start address of the
2102 * vma, merges and splits can happen in a seamless way, just
2103 * using the existing file pgoff checks and manipulations.
2104 * Similarly in do_mmap_pgoff and in do_brk.
2105 */
2106 if (!vma->vm_file) {
2107 BUG_ON(vma->anon_vma);
2108 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2109 }
2110 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2111 if (__vma && __vma->vm_start < vma->vm_end)
2112 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002113 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002114 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002115 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 vma_link(mm, vma, prev, rb_link, rb_parent);
2117 return 0;
2118}
2119
2120/*
2121 * Copy the vma structure to a new location in the same mm,
2122 * prior to moving page table entries, to effect an mremap move.
2123 */
2124struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2125 unsigned long addr, unsigned long len, pgoff_t pgoff)
2126{
2127 struct vm_area_struct *vma = *vmap;
2128 unsigned long vma_start = vma->vm_start;
2129 struct mm_struct *mm = vma->vm_mm;
2130 struct vm_area_struct *new_vma, *prev;
2131 struct rb_node **rb_link, *rb_parent;
2132 struct mempolicy *pol;
2133
2134 /*
2135 * If anonymous vma has not yet been faulted, update new pgoff
2136 * to match new location, to increase its chance of merging.
2137 */
2138 if (!vma->vm_file && !vma->anon_vma)
2139 pgoff = addr >> PAGE_SHIFT;
2140
2141 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2142 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2143 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2144 if (new_vma) {
2145 /*
2146 * Source vma may have been merged into new_vma
2147 */
2148 if (vma_start >= new_vma->vm_start &&
2149 vma_start < new_vma->vm_end)
2150 *vmap = new_vma;
2151 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002152 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 if (new_vma) {
2154 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002155 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 if (IS_ERR(pol)) {
2157 kmem_cache_free(vm_area_cachep, new_vma);
2158 return NULL;
2159 }
2160 vma_set_policy(new_vma, pol);
2161 new_vma->vm_start = addr;
2162 new_vma->vm_end = addr + len;
2163 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002164 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002166 if (vma->vm_flags & VM_EXECUTABLE)
2167 added_exe_file_vma(mm);
2168 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 if (new_vma->vm_ops && new_vma->vm_ops->open)
2170 new_vma->vm_ops->open(new_vma);
2171 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2172 }
2173 }
2174 return new_vma;
2175}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002176
2177/*
2178 * Return true if the calling process may expand its vm space by the passed
2179 * number of pages
2180 */
2181int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2182{
2183 unsigned long cur = mm->total_vm; /* pages */
2184 unsigned long lim;
2185
2186 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2187
2188 if (cur + npages > lim)
2189 return 0;
2190 return 1;
2191}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002192
2193
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002194static int special_mapping_fault(struct vm_area_struct *vma,
2195 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002196{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002197 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002198 struct page **pages;
2199
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002200 /*
2201 * special mappings have no vm_file, and in that case, the mm
2202 * uses vm_pgoff internally. So we have to subtract it from here.
2203 * We are allowed to do this because we are the mm; do not copy
2204 * this code into drivers!
2205 */
2206 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002207
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002208 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2209 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002210
2211 if (*pages) {
2212 struct page *page = *pages;
2213 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002214 vmf->page = page;
2215 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002216 }
2217
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002218 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002219}
2220
2221/*
2222 * Having a close hook prevents vma merging regardless of flags.
2223 */
2224static void special_mapping_close(struct vm_area_struct *vma)
2225{
2226}
2227
2228static struct vm_operations_struct special_mapping_vmops = {
2229 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002230 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002231};
2232
2233/*
2234 * Called with mm->mmap_sem held for writing.
2235 * Insert a new vma covering the given region, with the given flags.
2236 * Its pages are supplied by the given array of struct page *.
2237 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2238 * The region past the last page supplied will always produce SIGBUS.
2239 * The array pointer and the pages it points to are assumed to stay alive
2240 * for as long as this mapping might exist.
2241 */
2242int install_special_mapping(struct mm_struct *mm,
2243 unsigned long addr, unsigned long len,
2244 unsigned long vm_flags, struct page **pages)
2245{
2246 struct vm_area_struct *vma;
2247
2248 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2249 if (unlikely(vma == NULL))
2250 return -ENOMEM;
2251
2252 vma->vm_mm = mm;
2253 vma->vm_start = addr;
2254 vma->vm_end = addr + len;
2255
Nick Piggin2f987352008-02-02 03:08:53 +01002256 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002257 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002258
2259 vma->vm_ops = &special_mapping_vmops;
2260 vma->vm_private_data = pages;
2261
2262 if (unlikely(insert_vm_struct(mm, vma))) {
2263 kmem_cache_free(vm_area_cachep, vma);
2264 return -ENOMEM;
2265 }
2266
2267 mm->total_vm += len >> PAGE_SHIFT;
2268
2269 return 0;
2270}