blob: fac66337da2a3bcd3a003ba9d33096938c17fb57 [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
Kirill Korotaev3a459752006-09-07 14:17:04 +040035#ifndef arch_mmap_check
36#define arch_mmap_check(addr, len, flags) (0)
37#endif
38
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080039#ifndef arch_rebalance_pgtables
40#define arch_rebalance_pgtables(addr, len) (addr)
41#endif
42
Hugh Dickinse0da3822005-04-19 13:29:15 -070043static void unmap_region(struct mm_struct *mm,
44 struct vm_area_struct *vma, struct vm_area_struct *prev,
45 unsigned long start, unsigned long end);
46
Linus Torvalds1da177e2005-04-16 15:20:36 -070047/*
48 * WARNING: the debugging will use recursive algorithms so never enable this
49 * unless you know what you are doing.
50 */
51#undef DEBUG_MM_RB
52
53/* description of effects of mapping type and prot in current implementation.
54 * this is due to the limited x86 page protection hardware. The expected
55 * behavior is in parens:
56 *
57 * map_type prot
58 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
59 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
60 * w: (no) no w: (no) no w: (yes) yes w: (no) no
61 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
62 *
63 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
64 * w: (no) no w: (no) no w: (copy) copy w: (no) no
65 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
66 *
67 */
68pgprot_t protection_map[16] = {
69 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
70 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
71};
72
Hugh Dickins804af2c2006-07-26 21:39:49 +010073pgprot_t vm_get_page_prot(unsigned long vm_flags)
74{
75 return protection_map[vm_flags &
76 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
77}
78EXPORT_SYMBOL(vm_get_page_prot);
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
81int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070082int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070083atomic_t vm_committed_space = ATOMIC_INIT(0);
84
85/*
86 * Check that a process has enough memory to allocate a new virtual
87 * mapping. 0 means there is enough memory for the allocation to
88 * succeed and -ENOMEM implies there is not.
89 *
90 * We currently support three overcommit policies, which are set via the
91 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
92 *
93 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
94 * Additional code 2002 Jul 20 by Robert Love.
95 *
96 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
97 *
98 * Note this is a helper function intended to be used by LSMs which
99 * wish to use this logic.
100 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700101int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102{
103 unsigned long free, allowed;
104
105 vm_acct_memory(pages);
106
107 /*
108 * Sometimes we want to use more memory than we have
109 */
110 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
111 return 0;
112
113 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
114 unsigned long n;
115
Christoph Lameter347ce432006-06-30 01:55:35 -0700116 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 free += nr_swap_pages;
118
119 /*
120 * Any slabs which are created with the
121 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
122 * which are reclaimable, under pressure. The dentry
123 * cache and most inode caches should fall into this
124 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700125 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127 /*
128 * Leave the last 3% for root
129 */
130 if (!cap_sys_admin)
131 free -= free / 32;
132
133 if (free > pages)
134 return 0;
135
136 /*
137 * nr_free_pages() is very expensive on large systems,
138 * only call if we're about to fail.
139 */
140 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700141
142 /*
143 * Leave reserved pages. The pages are not for anonymous pages.
144 */
145 if (n <= totalreserve_pages)
146 goto error;
147 else
148 n -= totalreserve_pages;
149
150 /*
151 * Leave the last 3% for root
152 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 if (!cap_sys_admin)
154 n -= n / 32;
155 free += n;
156
157 if (free > pages)
158 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700159
160 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 }
162
163 allowed = (totalram_pages - hugetlb_total_pages())
164 * sysctl_overcommit_ratio / 100;
165 /*
166 * Leave the last 3% for root
167 */
168 if (!cap_sys_admin)
169 allowed -= allowed / 32;
170 allowed += total_swap_pages;
171
172 /* Don't let a single process grow too big:
173 leave 3% of the size of this process for other processes */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700174 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
Simon Derr2f60f8d2005-08-04 19:52:03 -0700176 /*
177 * cast `allowed' as a signed long because vm_committed_space
178 * sometimes has a negative value
179 */
180 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700182error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 vm_unacct_memory(pages);
184
185 return -ENOMEM;
186}
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188/*
189 * Requires inode->i_mapping->i_mmap_lock
190 */
191static void __remove_shared_vm_struct(struct vm_area_struct *vma,
192 struct file *file, struct address_space *mapping)
193{
194 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800195 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 if (vma->vm_flags & VM_SHARED)
197 mapping->i_mmap_writable--;
198
199 flush_dcache_mmap_lock(mapping);
200 if (unlikely(vma->vm_flags & VM_NONLINEAR))
201 list_del_init(&vma->shared.vm_set.list);
202 else
203 vma_prio_tree_remove(vma, &mapping->i_mmap);
204 flush_dcache_mmap_unlock(mapping);
205}
206
207/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700208 * Unlink a file-based vm structure from its prio_tree, to hide
209 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700211void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
213 struct file *file = vma->vm_file;
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 if (file) {
216 struct address_space *mapping = file->f_mapping;
217 spin_lock(&mapping->i_mmap_lock);
218 __remove_shared_vm_struct(vma, file, mapping);
219 spin_unlock(&mapping->i_mmap_lock);
220 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700221}
222
223/*
224 * Close a vm structure and free it, returning the next.
225 */
226static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
227{
228 struct vm_area_struct *next = vma->vm_next;
229
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700230 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 if (vma->vm_ops && vma->vm_ops->close)
232 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700233 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700234 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700235 if (vma->vm_flags & VM_EXECUTABLE)
236 removed_exe_file_vma(vma->vm_mm);
237 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700238 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700240 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241}
242
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243asmlinkage unsigned long sys_brk(unsigned long brk)
244{
245 unsigned long rlim, retval;
246 unsigned long newbrk, oldbrk;
247 struct mm_struct *mm = current->mm;
248
249 down_write(&mm->mmap_sem);
250
Jiri Kosina4cc60282008-02-06 22:39:44 +0100251 if (brk < mm->start_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700253
254 /*
255 * Check against rlimit here. If this check is done later after the test
256 * of oldbrk with newbrk then it can escape the test and let the data
257 * segment grow beyond its set limit the in case where the limit is
258 * not page aligned -Ram Gupta
259 */
260 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100261 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
262 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700263 goto out;
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 newbrk = PAGE_ALIGN(brk);
266 oldbrk = PAGE_ALIGN(mm->brk);
267 if (oldbrk == newbrk)
268 goto set_brk;
269
270 /* Always allow shrinking brk. */
271 if (brk <= mm->brk) {
272 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
273 goto set_brk;
274 goto out;
275 }
276
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 /* Check against existing mmap mappings. */
278 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
279 goto out;
280
281 /* Ok, looks good - let it rip. */
282 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
283 goto out;
284set_brk:
285 mm->brk = brk;
286out:
287 retval = mm->brk;
288 up_write(&mm->mmap_sem);
289 return retval;
290}
291
292#ifdef DEBUG_MM_RB
293static int browse_rb(struct rb_root *root)
294{
295 int i = 0, j;
296 struct rb_node *nd, *pn = NULL;
297 unsigned long prev = 0, pend = 0;
298
299 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
300 struct vm_area_struct *vma;
301 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
302 if (vma->vm_start < prev)
303 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
304 if (vma->vm_start < pend)
305 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
306 if (vma->vm_start > vma->vm_end)
307 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
308 i++;
309 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800310 prev = vma->vm_start;
311 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 }
313 j = 0;
314 for (nd = pn; nd; nd = rb_prev(nd)) {
315 j++;
316 }
317 if (i != j)
318 printk("backwards %d, forwards %d\n", j, i), i = 0;
319 return i;
320}
321
322void validate_mm(struct mm_struct *mm)
323{
324 int bug = 0;
325 int i = 0;
326 struct vm_area_struct *tmp = mm->mmap;
327 while (tmp) {
328 tmp = tmp->vm_next;
329 i++;
330 }
331 if (i != mm->map_count)
332 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
333 i = browse_rb(&mm->mm_rb);
334 if (i != mm->map_count)
335 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200336 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337}
338#else
339#define validate_mm(mm) do { } while (0)
340#endif
341
342static struct vm_area_struct *
343find_vma_prepare(struct mm_struct *mm, unsigned long addr,
344 struct vm_area_struct **pprev, struct rb_node ***rb_link,
345 struct rb_node ** rb_parent)
346{
347 struct vm_area_struct * vma;
348 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
349
350 __rb_link = &mm->mm_rb.rb_node;
351 rb_prev = __rb_parent = NULL;
352 vma = NULL;
353
354 while (*__rb_link) {
355 struct vm_area_struct *vma_tmp;
356
357 __rb_parent = *__rb_link;
358 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
359
360 if (vma_tmp->vm_end > addr) {
361 vma = vma_tmp;
362 if (vma_tmp->vm_start <= addr)
363 return vma;
364 __rb_link = &__rb_parent->rb_left;
365 } else {
366 rb_prev = __rb_parent;
367 __rb_link = &__rb_parent->rb_right;
368 }
369 }
370
371 *pprev = NULL;
372 if (rb_prev)
373 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
374 *rb_link = __rb_link;
375 *rb_parent = __rb_parent;
376 return vma;
377}
378
379static inline void
380__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
381 struct vm_area_struct *prev, struct rb_node *rb_parent)
382{
383 if (prev) {
384 vma->vm_next = prev->vm_next;
385 prev->vm_next = vma;
386 } else {
387 mm->mmap = vma;
388 if (rb_parent)
389 vma->vm_next = rb_entry(rb_parent,
390 struct vm_area_struct, vm_rb);
391 else
392 vma->vm_next = NULL;
393 }
394}
395
396void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
397 struct rb_node **rb_link, struct rb_node *rb_parent)
398{
399 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
400 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
401}
402
403static inline void __vma_link_file(struct vm_area_struct *vma)
404{
405 struct file * file;
406
407 file = vma->vm_file;
408 if (file) {
409 struct address_space *mapping = file->f_mapping;
410
411 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800412 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 if (vma->vm_flags & VM_SHARED)
414 mapping->i_mmap_writable++;
415
416 flush_dcache_mmap_lock(mapping);
417 if (unlikely(vma->vm_flags & VM_NONLINEAR))
418 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
419 else
420 vma_prio_tree_insert(vma, &mapping->i_mmap);
421 flush_dcache_mmap_unlock(mapping);
422 }
423}
424
425static void
426__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
427 struct vm_area_struct *prev, struct rb_node **rb_link,
428 struct rb_node *rb_parent)
429{
430 __vma_link_list(mm, vma, prev, rb_parent);
431 __vma_link_rb(mm, vma, rb_link, rb_parent);
432 __anon_vma_link(vma);
433}
434
435static void 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 struct address_space *mapping = NULL;
440
441 if (vma->vm_file)
442 mapping = vma->vm_file->f_mapping;
443
444 if (mapping) {
445 spin_lock(&mapping->i_mmap_lock);
446 vma->vm_truncate_count = mapping->truncate_count;
447 }
448 anon_vma_lock(vma);
449
450 __vma_link(mm, vma, prev, rb_link, rb_parent);
451 __vma_link_file(vma);
452
453 anon_vma_unlock(vma);
454 if (mapping)
455 spin_unlock(&mapping->i_mmap_lock);
456
457 mm->map_count++;
458 validate_mm(mm);
459}
460
461/*
462 * Helper for vma_adjust in the split_vma insert case:
463 * insert vm structure into list and rbtree and anon_vma,
464 * but it has already been inserted into prio_tree earlier.
465 */
466static void
467__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
468{
469 struct vm_area_struct * __vma, * prev;
470 struct rb_node ** rb_link, * rb_parent;
471
472 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200473 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 __vma_link(mm, vma, prev, rb_link, rb_parent);
475 mm->map_count++;
476}
477
478static inline void
479__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
480 struct vm_area_struct *prev)
481{
482 prev->vm_next = vma->vm_next;
483 rb_erase(&vma->vm_rb, &mm->mm_rb);
484 if (mm->mmap_cache == vma)
485 mm->mmap_cache = prev;
486}
487
488/*
489 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
490 * is already present in an i_mmap tree without adjusting the tree.
491 * The following helper function should be used when such adjustments
492 * are necessary. The "insert" vma (if any) is to be inserted
493 * before we drop the necessary locks.
494 */
495void vma_adjust(struct vm_area_struct *vma, unsigned long start,
496 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
497{
498 struct mm_struct *mm = vma->vm_mm;
499 struct vm_area_struct *next = vma->vm_next;
500 struct vm_area_struct *importer = NULL;
501 struct address_space *mapping = NULL;
502 struct prio_tree_root *root = NULL;
503 struct file *file = vma->vm_file;
504 struct anon_vma *anon_vma = NULL;
505 long adjust_next = 0;
506 int remove_next = 0;
507
508 if (next && !insert) {
509 if (end >= next->vm_end) {
510 /*
511 * vma expands, overlapping all the next, and
512 * perhaps the one after too (mprotect case 6).
513 */
514again: remove_next = 1 + (end > next->vm_end);
515 end = next->vm_end;
516 anon_vma = next->anon_vma;
517 importer = vma;
518 } else if (end > next->vm_start) {
519 /*
520 * vma expands, overlapping part of the next:
521 * mprotect case 5 shifting the boundary up.
522 */
523 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
524 anon_vma = next->anon_vma;
525 importer = vma;
526 } else if (end < vma->vm_end) {
527 /*
528 * vma shrinks, and !insert tells it's not
529 * split_vma inserting another: so it must be
530 * mprotect case 4 shifting the boundary down.
531 */
532 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
533 anon_vma = next->anon_vma;
534 importer = next;
535 }
536 }
537
538 if (file) {
539 mapping = file->f_mapping;
540 if (!(vma->vm_flags & VM_NONLINEAR))
541 root = &mapping->i_mmap;
542 spin_lock(&mapping->i_mmap_lock);
543 if (importer &&
544 vma->vm_truncate_count != next->vm_truncate_count) {
545 /*
546 * unmap_mapping_range might be in progress:
547 * ensure that the expanding vma is rescanned.
548 */
549 importer->vm_truncate_count = 0;
550 }
551 if (insert) {
552 insert->vm_truncate_count = vma->vm_truncate_count;
553 /*
554 * Put into prio_tree now, so instantiated pages
555 * are visible to arm/parisc __flush_dcache_page
556 * throughout; but we cannot insert into address
557 * space until vma start or end is updated.
558 */
559 __vma_link_file(insert);
560 }
561 }
562
563 /*
564 * When changing only vma->vm_end, we don't really need
565 * anon_vma lock: but is that case worth optimizing out?
566 */
567 if (vma->anon_vma)
568 anon_vma = vma->anon_vma;
569 if (anon_vma) {
570 spin_lock(&anon_vma->lock);
571 /*
572 * Easily overlooked: when mprotect shifts the boundary,
573 * make sure the expanding vma has anon_vma set if the
574 * shrinking vma had, to cover any anon pages imported.
575 */
576 if (importer && !importer->anon_vma) {
577 importer->anon_vma = anon_vma;
578 __anon_vma_link(importer);
579 }
580 }
581
582 if (root) {
583 flush_dcache_mmap_lock(mapping);
584 vma_prio_tree_remove(vma, root);
585 if (adjust_next)
586 vma_prio_tree_remove(next, root);
587 }
588
589 vma->vm_start = start;
590 vma->vm_end = end;
591 vma->vm_pgoff = pgoff;
592 if (adjust_next) {
593 next->vm_start += adjust_next << PAGE_SHIFT;
594 next->vm_pgoff += adjust_next;
595 }
596
597 if (root) {
598 if (adjust_next)
599 vma_prio_tree_insert(next, root);
600 vma_prio_tree_insert(vma, root);
601 flush_dcache_mmap_unlock(mapping);
602 }
603
604 if (remove_next) {
605 /*
606 * vma_merge has merged next into vma, and needs
607 * us to remove next before dropping the locks.
608 */
609 __vma_unlink(mm, next, vma);
610 if (file)
611 __remove_shared_vm_struct(next, file, mapping);
612 if (next->anon_vma)
613 __anon_vma_merge(vma, next);
614 } else if (insert) {
615 /*
616 * split_vma has split insert from vma, and needs
617 * us to insert it before dropping the locks
618 * (it may either follow vma or precede it).
619 */
620 __insert_vm_struct(mm, insert);
621 }
622
623 if (anon_vma)
624 spin_unlock(&anon_vma->lock);
625 if (mapping)
626 spin_unlock(&mapping->i_mmap_lock);
627
628 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700629 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700631 if (next->vm_flags & VM_EXECUTABLE)
632 removed_exe_file_vma(mm);
633 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700635 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 kmem_cache_free(vm_area_cachep, next);
637 /*
638 * In mprotect's case 6 (see comments on vma_merge),
639 * we must remove another next too. It would clutter
640 * up the code too much to do both in one go.
641 */
642 if (remove_next == 2) {
643 next = vma->vm_next;
644 goto again;
645 }
646 }
647
648 validate_mm(mm);
649}
650
651/*
652 * If the vma has a ->close operation then the driver probably needs to release
653 * per-vma resources, so we don't attempt to merge those.
654 */
Hugh Dickinsa6f563d2006-03-22 00:08:29 -0800655#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
657static inline int is_mergeable_vma(struct vm_area_struct *vma,
658 struct file *file, unsigned long vm_flags)
659{
660 if (vma->vm_flags != vm_flags)
661 return 0;
662 if (vma->vm_file != file)
663 return 0;
664 if (vma->vm_ops && vma->vm_ops->close)
665 return 0;
666 return 1;
667}
668
669static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
670 struct anon_vma *anon_vma2)
671{
672 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
673}
674
675/*
676 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
677 * in front of (at a lower virtual address and file offset than) the vma.
678 *
679 * We cannot merge two vmas if they have differently assigned (non-NULL)
680 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
681 *
682 * We don't check here for the merged mmap wrapping around the end of pagecache
683 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
684 * wrap, nor mmaps which cover the final page at index -1UL.
685 */
686static int
687can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
688 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
689{
690 if (is_mergeable_vma(vma, file, vm_flags) &&
691 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
692 if (vma->vm_pgoff == vm_pgoff)
693 return 1;
694 }
695 return 0;
696}
697
698/*
699 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
700 * beyond (at a higher virtual address and file offset than) the vma.
701 *
702 * We cannot merge two vmas if they have differently assigned (non-NULL)
703 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
704 */
705static int
706can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
707 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
708{
709 if (is_mergeable_vma(vma, file, vm_flags) &&
710 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
711 pgoff_t vm_pglen;
712 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
713 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
714 return 1;
715 }
716 return 0;
717}
718
719/*
720 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
721 * whether that can be merged with its predecessor or its successor.
722 * Or both (it neatly fills a hole).
723 *
724 * In most cases - when called for mmap, brk or mremap - [addr,end) is
725 * certain not to be mapped by the time vma_merge is called; but when
726 * called for mprotect, it is certain to be already mapped (either at
727 * an offset within prev, or at the start of next), and the flags of
728 * this area are about to be changed to vm_flags - and the no-change
729 * case has already been eliminated.
730 *
731 * The following mprotect cases have to be considered, where AAAA is
732 * the area passed down from mprotect_fixup, never extending beyond one
733 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
734 *
735 * AAAA AAAA AAAA AAAA
736 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
737 * cannot merge might become might become might become
738 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
739 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
740 * mremap move: PPPPNNNNNNNN 8
741 * AAAA
742 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
743 * might become case 1 below case 2 below case 3 below
744 *
745 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
746 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
747 */
748struct vm_area_struct *vma_merge(struct mm_struct *mm,
749 struct vm_area_struct *prev, unsigned long addr,
750 unsigned long end, unsigned long vm_flags,
751 struct anon_vma *anon_vma, struct file *file,
752 pgoff_t pgoff, struct mempolicy *policy)
753{
754 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
755 struct vm_area_struct *area, *next;
756
757 /*
758 * We later require that vma->vm_flags == vm_flags,
759 * so this tests vma->vm_flags & VM_SPECIAL, too.
760 */
761 if (vm_flags & VM_SPECIAL)
762 return NULL;
763
764 if (prev)
765 next = prev->vm_next;
766 else
767 next = mm->mmap;
768 area = next;
769 if (next && next->vm_end == end) /* cases 6, 7, 8 */
770 next = next->vm_next;
771
772 /*
773 * Can it merge with the predecessor?
774 */
775 if (prev && prev->vm_end == addr &&
776 mpol_equal(vma_policy(prev), policy) &&
777 can_vma_merge_after(prev, vm_flags,
778 anon_vma, file, pgoff)) {
779 /*
780 * OK, it can. Can we now merge in the successor as well?
781 */
782 if (next && end == next->vm_start &&
783 mpol_equal(policy, vma_policy(next)) &&
784 can_vma_merge_before(next, vm_flags,
785 anon_vma, file, pgoff+pglen) &&
786 is_mergeable_anon_vma(prev->anon_vma,
787 next->anon_vma)) {
788 /* cases 1, 6 */
789 vma_adjust(prev, prev->vm_start,
790 next->vm_end, prev->vm_pgoff, NULL);
791 } else /* cases 2, 5, 7 */
792 vma_adjust(prev, prev->vm_start,
793 end, prev->vm_pgoff, NULL);
794 return prev;
795 }
796
797 /*
798 * Can this new request be merged in front of next?
799 */
800 if (next && end == next->vm_start &&
801 mpol_equal(policy, vma_policy(next)) &&
802 can_vma_merge_before(next, vm_flags,
803 anon_vma, file, pgoff+pglen)) {
804 if (prev && addr < prev->vm_end) /* case 4 */
805 vma_adjust(prev, prev->vm_start,
806 addr, prev->vm_pgoff, NULL);
807 else /* cases 3, 8 */
808 vma_adjust(area, addr, next->vm_end,
809 next->vm_pgoff - pglen, NULL);
810 return area;
811 }
812
813 return NULL;
814}
815
816/*
817 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
818 * neighbouring vmas for a suitable anon_vma, before it goes off
819 * to allocate a new anon_vma. It checks because a repetitive
820 * sequence of mprotects and faults may otherwise lead to distinct
821 * anon_vmas being allocated, preventing vma merge in subsequent
822 * mprotect.
823 */
824struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
825{
826 struct vm_area_struct *near;
827 unsigned long vm_flags;
828
829 near = vma->vm_next;
830 if (!near)
831 goto try_prev;
832
833 /*
834 * Since only mprotect tries to remerge vmas, match flags
835 * which might be mprotected into each other later on.
836 * Neither mlock nor madvise tries to remerge at present,
837 * so leave their flags as obstructing a merge.
838 */
839 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
840 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
841
842 if (near->anon_vma && vma->vm_end == near->vm_start &&
843 mpol_equal(vma_policy(vma), vma_policy(near)) &&
844 can_vma_merge_before(near, vm_flags,
845 NULL, vma->vm_file, vma->vm_pgoff +
846 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
847 return near->anon_vma;
848try_prev:
849 /*
850 * It is potentially slow to have to call find_vma_prev here.
851 * But it's only on the first write fault on the vma, not
852 * every time, and we could devise a way to avoid it later
853 * (e.g. stash info in next's anon_vma_node when assigning
854 * an anon_vma, or when trying vma_merge). Another time.
855 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200856 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 if (!near)
858 goto none;
859
860 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
861 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
862
863 if (near->anon_vma && near->vm_end == vma->vm_start &&
864 mpol_equal(vma_policy(near), vma_policy(vma)) &&
865 can_vma_merge_after(near, vm_flags,
866 NULL, vma->vm_file, vma->vm_pgoff))
867 return near->anon_vma;
868none:
869 /*
870 * There's no absolute need to look only at touching neighbours:
871 * we could search further afield for "compatible" anon_vmas.
872 * But it would probably just be a waste of time searching,
873 * or lead to too many vmas hanging off the same anon_vma.
874 * We're trying to allow mprotect remerging later on,
875 * not trying to minimize memory used for anon_vmas.
876 */
877 return NULL;
878}
879
880#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700881void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 struct file *file, long pages)
883{
884 const unsigned long stack_flags
885 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
886
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 if (file) {
888 mm->shared_vm += pages;
889 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
890 mm->exec_vm += pages;
891 } else if (flags & stack_flags)
892 mm->stack_vm += pages;
893 if (flags & (VM_RESERVED|VM_IO))
894 mm->reserved_vm += pages;
895}
896#endif /* CONFIG_PROC_FS */
897
898/*
899 * The caller must hold down_write(current->mm->mmap_sem).
900 */
901
902unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
903 unsigned long len, unsigned long prot,
904 unsigned long flags, unsigned long pgoff)
905{
906 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 struct inode *inode;
908 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 int accountable = 1;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700911 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 /*
914 * Does the application expect PROT_READ to imply PROT_EXEC?
915 *
916 * (the exception is when the underlying filesystem is noexec
917 * mounted, in which case we dont add PROT_EXEC.)
918 */
919 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800920 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 prot |= PROT_EXEC;
922
923 if (!len)
924 return -EINVAL;
925
Eric Paris7cd94142007-11-26 18:47:40 -0500926 if (!(flags & MAP_FIXED))
927 addr = round_hint_to_min(addr);
928
Kirill Korotaev3a459752006-09-07 14:17:04 +0400929 error = arch_mmap_check(addr, len, flags);
930 if (error)
931 return error;
932
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 /* Careful about overflows.. */
934 len = PAGE_ALIGN(len);
935 if (!len || len > TASK_SIZE)
936 return -ENOMEM;
937
938 /* offset overflow? */
939 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
940 return -EOVERFLOW;
941
942 /* Too many mappings? */
943 if (mm->map_count > sysctl_max_map_count)
944 return -ENOMEM;
945
946 /* Obtain the address to map to. we verify (or select) it and ensure
947 * that it represents a valid section of the address space.
948 */
949 addr = get_unmapped_area(file, addr, len, pgoff, flags);
950 if (addr & ~PAGE_MASK)
951 return addr;
952
953 /* Do simple checking here so the lower-level routines won't have
954 * to. we assume access permissions have been handled by the open
955 * of the memory object, so we don't do any here.
956 */
957 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
958 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
959
960 if (flags & MAP_LOCKED) {
961 if (!can_do_mlock())
962 return -EPERM;
963 vm_flags |= VM_LOCKED;
964 }
965 /* mlock MCL_FUTURE? */
966 if (vm_flags & VM_LOCKED) {
967 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700968 locked = len >> PAGE_SHIFT;
969 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700971 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
973 return -EAGAIN;
974 }
975
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800976 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
978 if (file) {
979 switch (flags & MAP_TYPE) {
980 case MAP_SHARED:
981 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
982 return -EACCES;
983
984 /*
985 * Make sure we don't allow writing to an append-only
986 * file..
987 */
988 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
989 return -EACCES;
990
991 /*
992 * Make sure there are no mandatory locks on the file.
993 */
994 if (locks_verify_locked(inode))
995 return -EAGAIN;
996
997 vm_flags |= VM_SHARED | VM_MAYSHARE;
998 if (!(file->f_mode & FMODE_WRITE))
999 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1000
1001 /* fall through */
1002 case MAP_PRIVATE:
1003 if (!(file->f_mode & FMODE_READ))
1004 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001005 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001006 if (vm_flags & VM_EXEC)
1007 return -EPERM;
1008 vm_flags &= ~VM_MAYEXEC;
1009 }
1010 if (is_file_hugepages(file))
1011 accountable = 0;
1012
1013 if (!file->f_op || !file->f_op->mmap)
1014 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 break;
1016
1017 default:
1018 return -EINVAL;
1019 }
1020 } else {
1021 switch (flags & MAP_TYPE) {
1022 case MAP_SHARED:
1023 vm_flags |= VM_SHARED | VM_MAYSHARE;
1024 break;
1025 case MAP_PRIVATE:
1026 /*
1027 * Set pgoff according to addr for anon_vma.
1028 */
1029 pgoff = addr >> PAGE_SHIFT;
1030 break;
1031 default:
1032 return -EINVAL;
1033 }
1034 }
1035
Eric Parised032182007-06-28 15:55:21 -04001036 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 if (error)
1038 return error;
Eric Parised032182007-06-28 15:55:21 -04001039
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001040 return mmap_region(file, addr, len, flags, vm_flags, pgoff,
1041 accountable);
1042}
1043EXPORT_SYMBOL(do_mmap_pgoff);
1044
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001045/*
1046 * Some shared mappigns will want the pages marked read-only
1047 * to track write events. If so, we'll downgrade vm_page_prot
1048 * to the private version (using protection_map[] without the
1049 * VM_SHARED bit).
1050 */
1051int vma_wants_writenotify(struct vm_area_struct *vma)
1052{
1053 unsigned int vm_flags = vma->vm_flags;
1054
1055 /* If it was private or non-writable, the write bit is already clear */
1056 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1057 return 0;
1058
1059 /* The backer wishes to know when pages are first written to? */
1060 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1061 return 1;
1062
1063 /* The open routine did something to the protections already? */
1064 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001065 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001066 return 0;
1067
1068 /* Specialty mapping? */
1069 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1070 return 0;
1071
1072 /* Can the mapping track the dirty pages? */
1073 return vma->vm_file && vma->vm_file->f_mapping &&
1074 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1075}
1076
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001077unsigned long mmap_region(struct file *file, unsigned long addr,
1078 unsigned long len, unsigned long flags,
1079 unsigned int vm_flags, unsigned long pgoff,
1080 int accountable)
1081{
1082 struct mm_struct *mm = current->mm;
1083 struct vm_area_struct *vma, *prev;
1084 int correct_wcount = 0;
1085 int error;
1086 struct rb_node **rb_link, *rb_parent;
1087 unsigned long charged = 0;
1088 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1089
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 /* Clear old maps */
1091 error = -ENOMEM;
1092munmap_back:
1093 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1094 if (vma && vma->vm_start < addr + len) {
1095 if (do_munmap(mm, addr, len))
1096 return -ENOMEM;
1097 goto munmap_back;
1098 }
1099
1100 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001101 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 return -ENOMEM;
1103
1104 if (accountable && (!(flags & MAP_NORESERVE) ||
1105 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1106 if (vm_flags & VM_SHARED) {
1107 /* Check memory availability in shmem_file_setup? */
1108 vm_flags |= VM_ACCOUNT;
1109 } else if (vm_flags & VM_WRITE) {
1110 /*
1111 * Private writable mapping: check memory availability
1112 */
1113 charged = len >> PAGE_SHIFT;
1114 if (security_vm_enough_memory(charged))
1115 return -ENOMEM;
1116 vm_flags |= VM_ACCOUNT;
1117 }
1118 }
1119
1120 /*
1121 * Can we just expand an old private anonymous mapping?
1122 * The VM_SHARED test is necessary because shmem_zero_setup
1123 * will create the file object for a shared anonymous map below.
1124 */
1125 if (!file && !(vm_flags & VM_SHARED) &&
1126 vma_merge(mm, prev, addr, addr + len, vm_flags,
1127 NULL, NULL, pgoff, NULL))
1128 goto out;
1129
1130 /*
1131 * Determine the object being mapped and call the appropriate
1132 * specific mapper. the address has already been validated, but
1133 * not unmapped, but the maps are removed from the list.
1134 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001135 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 if (!vma) {
1137 error = -ENOMEM;
1138 goto unacct_error;
1139 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140
1141 vma->vm_mm = mm;
1142 vma->vm_start = addr;
1143 vma->vm_end = addr + len;
1144 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001145 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 vma->vm_pgoff = pgoff;
1147
1148 if (file) {
1149 error = -EINVAL;
1150 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1151 goto free_vma;
1152 if (vm_flags & VM_DENYWRITE) {
1153 error = deny_write_access(file);
1154 if (error)
1155 goto free_vma;
1156 correct_wcount = 1;
1157 }
1158 vma->vm_file = file;
1159 get_file(file);
1160 error = file->f_op->mmap(file, vma);
1161 if (error)
1162 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001163 if (vm_flags & VM_EXECUTABLE)
1164 added_exe_file_vma(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 } else if (vm_flags & VM_SHARED) {
1166 error = shmem_zero_setup(vma);
1167 if (error)
1168 goto free_vma;
1169 }
1170
1171 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1172 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1173 * that memory reservation must be checked; but that reservation
1174 * belongs to shared memory object, not to vma: so now clear it.
1175 */
1176 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1177 vma->vm_flags &= ~VM_ACCOUNT;
1178
1179 /* Can addr have changed??
1180 *
1181 * Answer: Yes, several device drivers can do it in their
1182 * f_op->mmap method. -DaveM
1183 */
1184 addr = vma->vm_start;
1185 pgoff = vma->vm_pgoff;
1186 vm_flags = vma->vm_flags;
1187
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001188 if (vma_wants_writenotify(vma))
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001189 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001190
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001191 if (file && vma_merge(mm, prev, addr, vma->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
Lee Schermerhornf0be3d32008-04-28 02:13:08 -07001193 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 kmem_cache_free(vm_area_cachep, vma);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001195 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001196 if (vm_flags & VM_EXECUTABLE)
1197 removed_exe_file_vma(mm);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001198 } else {
1199 vma_link(mm, vma, prev, rb_link, rb_parent);
1200 file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 }
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001202
1203 /* Once vma denies write, undo our temporary denial count */
1204 if (correct_wcount)
1205 atomic_inc(&inode->i_writecount);
1206out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001208 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 if (vm_flags & VM_LOCKED) {
1210 mm->locked_vm += len >> PAGE_SHIFT;
1211 make_pages_present(addr, addr + len);
1212 }
Nick Piggin54cb8822007-07-19 01:46:59 -07001213 if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1214 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 return addr;
1216
1217unmap_and_free_vma:
1218 if (correct_wcount)
1219 atomic_inc(&inode->i_writecount);
1220 vma->vm_file = NULL;
1221 fput(file);
1222
1223 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001224 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1225 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226free_vma:
1227 kmem_cache_free(vm_area_cachep, vma);
1228unacct_error:
1229 if (charged)
1230 vm_unacct_memory(charged);
1231 return error;
1232}
1233
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234/* Get an address range which is currently unmapped.
1235 * For shmat() with addr=0.
1236 *
1237 * Ugly calling convention alert:
1238 * Return value with the low bits set means error value,
1239 * ie
1240 * if (ret & ~PAGE_MASK)
1241 * error = ret;
1242 *
1243 * This function "knows" that -ENOMEM has the bits set.
1244 */
1245#ifndef HAVE_ARCH_UNMAPPED_AREA
1246unsigned long
1247arch_get_unmapped_area(struct file *filp, unsigned long addr,
1248 unsigned long len, unsigned long pgoff, unsigned long flags)
1249{
1250 struct mm_struct *mm = current->mm;
1251 struct vm_area_struct *vma;
1252 unsigned long start_addr;
1253
1254 if (len > TASK_SIZE)
1255 return -ENOMEM;
1256
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001257 if (flags & MAP_FIXED)
1258 return addr;
1259
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 if (addr) {
1261 addr = PAGE_ALIGN(addr);
1262 vma = find_vma(mm, addr);
1263 if (TASK_SIZE - len >= addr &&
1264 (!vma || addr + len <= vma->vm_start))
1265 return addr;
1266 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001267 if (len > mm->cached_hole_size) {
1268 start_addr = addr = mm->free_area_cache;
1269 } else {
1270 start_addr = addr = TASK_UNMAPPED_BASE;
1271 mm->cached_hole_size = 0;
1272 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
1274full_search:
1275 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1276 /* At this point: (!vma || addr < vma->vm_end). */
1277 if (TASK_SIZE - len < addr) {
1278 /*
1279 * Start a new search - just in case we missed
1280 * some holes.
1281 */
1282 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001283 addr = TASK_UNMAPPED_BASE;
1284 start_addr = addr;
1285 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 goto full_search;
1287 }
1288 return -ENOMEM;
1289 }
1290 if (!vma || addr + len <= vma->vm_start) {
1291 /*
1292 * Remember the place where we stopped the search:
1293 */
1294 mm->free_area_cache = addr + len;
1295 return addr;
1296 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001297 if (addr + mm->cached_hole_size < vma->vm_start)
1298 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 addr = vma->vm_end;
1300 }
1301}
1302#endif
1303
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001304void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305{
1306 /*
1307 * Is this a new hole at the lowest possible address?
1308 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001309 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1310 mm->free_area_cache = addr;
1311 mm->cached_hole_size = ~0UL;
1312 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313}
1314
1315/*
1316 * This mmap-allocator allocates new areas top-down from below the
1317 * stack's low limit (the base):
1318 */
1319#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1320unsigned long
1321arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1322 const unsigned long len, const unsigned long pgoff,
1323 const unsigned long flags)
1324{
1325 struct vm_area_struct *vma;
1326 struct mm_struct *mm = current->mm;
1327 unsigned long addr = addr0;
1328
1329 /* requested length too big for entire address space */
1330 if (len > TASK_SIZE)
1331 return -ENOMEM;
1332
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001333 if (flags & MAP_FIXED)
1334 return addr;
1335
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 /* requesting a specific address */
1337 if (addr) {
1338 addr = PAGE_ALIGN(addr);
1339 vma = find_vma(mm, addr);
1340 if (TASK_SIZE - len >= addr &&
1341 (!vma || addr + len <= vma->vm_start))
1342 return addr;
1343 }
1344
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001345 /* check if free_area_cache is useful for us */
1346 if (len <= mm->cached_hole_size) {
1347 mm->cached_hole_size = 0;
1348 mm->free_area_cache = mm->mmap_base;
1349 }
1350
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 /* either no address requested or can't fit in requested address hole */
1352 addr = mm->free_area_cache;
1353
1354 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001355 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 vma = find_vma(mm, addr-len);
1357 if (!vma || addr <= vma->vm_start)
1358 /* remember the address as a hint for next time */
1359 return (mm->free_area_cache = addr-len);
1360 }
1361
Chris Wright73219d12005-06-21 17:14:52 -07001362 if (mm->mmap_base < len)
1363 goto bottomup;
1364
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 addr = mm->mmap_base-len;
1366
1367 do {
1368 /*
1369 * Lookup failure means no vma is above this address,
1370 * else if new region fits below vma->vm_start,
1371 * return with success:
1372 */
1373 vma = find_vma(mm, addr);
1374 if (!vma || addr+len <= vma->vm_start)
1375 /* remember the address as a hint for next time */
1376 return (mm->free_area_cache = addr);
1377
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001378 /* remember the largest hole we saw so far */
1379 if (addr + mm->cached_hole_size < vma->vm_start)
1380 mm->cached_hole_size = vma->vm_start - addr;
1381
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 /* try just below the current vma->vm_start */
1383 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001384 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385
Chris Wright73219d12005-06-21 17:14:52 -07001386bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 /*
1388 * A failed mmap() very likely causes application failure,
1389 * so fall back to the bottom-up function here. This scenario
1390 * can happen with large stack limits and large mmap()
1391 * allocations.
1392 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001393 mm->cached_hole_size = ~0UL;
1394 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1396 /*
1397 * Restore the topdown base:
1398 */
1399 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001400 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
1402 return addr;
1403}
1404#endif
1405
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001406void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407{
1408 /*
1409 * Is this a new hole at the highest possible address?
1410 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001411 if (addr > mm->free_area_cache)
1412 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
1414 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001415 if (mm->free_area_cache > mm->mmap_base)
1416 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417}
1418
1419unsigned long
1420get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1421 unsigned long pgoff, unsigned long flags)
1422{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001423 unsigned long (*get_area)(struct file *, unsigned long,
1424 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001426 get_area = current->mm->get_unmapped_area;
1427 if (file && file->f_op && file->f_op->get_unmapped_area)
1428 get_area = file->f_op->get_unmapped_area;
1429 addr = get_area(file, addr, len, pgoff, flags);
1430 if (IS_ERR_VALUE(addr))
1431 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001433 if (addr > TASK_SIZE - len)
1434 return -ENOMEM;
1435 if (addr & ~PAGE_MASK)
1436 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001437
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001438 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439}
1440
1441EXPORT_SYMBOL(get_unmapped_area);
1442
1443/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1444struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1445{
1446 struct vm_area_struct *vma = NULL;
1447
1448 if (mm) {
1449 /* Check the cache first. */
1450 /* (Cache hit rate is typically around 35%.) */
1451 vma = mm->mmap_cache;
1452 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1453 struct rb_node * rb_node;
1454
1455 rb_node = mm->mm_rb.rb_node;
1456 vma = NULL;
1457
1458 while (rb_node) {
1459 struct vm_area_struct * vma_tmp;
1460
1461 vma_tmp = rb_entry(rb_node,
1462 struct vm_area_struct, vm_rb);
1463
1464 if (vma_tmp->vm_end > addr) {
1465 vma = vma_tmp;
1466 if (vma_tmp->vm_start <= addr)
1467 break;
1468 rb_node = rb_node->rb_left;
1469 } else
1470 rb_node = rb_node->rb_right;
1471 }
1472 if (vma)
1473 mm->mmap_cache = vma;
1474 }
1475 }
1476 return vma;
1477}
1478
1479EXPORT_SYMBOL(find_vma);
1480
1481/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1482struct vm_area_struct *
1483find_vma_prev(struct mm_struct *mm, unsigned long addr,
1484 struct vm_area_struct **pprev)
1485{
1486 struct vm_area_struct *vma = NULL, *prev = NULL;
1487 struct rb_node * rb_node;
1488 if (!mm)
1489 goto out;
1490
1491 /* Guard against addr being lower than the first VMA */
1492 vma = mm->mmap;
1493
1494 /* Go through the RB tree quickly. */
1495 rb_node = mm->mm_rb.rb_node;
1496
1497 while (rb_node) {
1498 struct vm_area_struct *vma_tmp;
1499 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1500
1501 if (addr < vma_tmp->vm_end) {
1502 rb_node = rb_node->rb_left;
1503 } else {
1504 prev = vma_tmp;
1505 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1506 break;
1507 rb_node = rb_node->rb_right;
1508 }
1509 }
1510
1511out:
1512 *pprev = prev;
1513 return prev ? prev->vm_next : vma;
1514}
1515
1516/*
1517 * Verify that the stack growth is acceptable and
1518 * update accounting. This is shared with both the
1519 * grow-up and grow-down cases.
1520 */
1521static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1522{
1523 struct mm_struct *mm = vma->vm_mm;
1524 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001525 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526
1527 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001528 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 return -ENOMEM;
1530
1531 /* Stack limit test */
1532 if (size > rlim[RLIMIT_STACK].rlim_cur)
1533 return -ENOMEM;
1534
1535 /* mlock limit tests */
1536 if (vma->vm_flags & VM_LOCKED) {
1537 unsigned long locked;
1538 unsigned long limit;
1539 locked = mm->locked_vm + grow;
1540 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1541 if (locked > limit && !capable(CAP_IPC_LOCK))
1542 return -ENOMEM;
1543 }
1544
Adam Litke0d59a012007-01-30 14:35:39 -08001545 /* Check to ensure the stack will not grow into a hugetlb-only region */
1546 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1547 vma->vm_end - size;
1548 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1549 return -EFAULT;
1550
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 /*
1552 * Overcommit.. This must be the final test, as it will
1553 * update security statistics.
1554 */
1555 if (security_vm_enough_memory(grow))
1556 return -ENOMEM;
1557
1558 /* Ok, everything looks good - let it rip */
1559 mm->total_vm += grow;
1560 if (vma->vm_flags & VM_LOCKED)
1561 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001562 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563 return 0;
1564}
1565
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001566#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001568 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1569 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001571#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001572static inline
1573#endif
1574int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575{
1576 int error;
1577
1578 if (!(vma->vm_flags & VM_GROWSUP))
1579 return -EFAULT;
1580
1581 /*
1582 * We must make sure the anon_vma is allocated
1583 * so that the anon_vma locking is not a noop.
1584 */
1585 if (unlikely(anon_vma_prepare(vma)))
1586 return -ENOMEM;
1587 anon_vma_lock(vma);
1588
1589 /*
1590 * vma->vm_start/vm_end cannot change under us because the caller
1591 * is required to hold the mmap_sem in read mode. We need the
1592 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001593 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 */
Helge Deller06b32f32006-12-19 19:28:33 +01001595 if (address < PAGE_ALIGN(address+4))
1596 address = PAGE_ALIGN(address+4);
1597 else {
1598 anon_vma_unlock(vma);
1599 return -ENOMEM;
1600 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601 error = 0;
1602
1603 /* Somebody else might have raced and expanded it already */
1604 if (address > vma->vm_end) {
1605 unsigned long size, grow;
1606
1607 size = address - vma->vm_start;
1608 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1609
1610 error = acct_stack_growth(vma, size, grow);
1611 if (!error)
1612 vma->vm_end = address;
1613 }
1614 anon_vma_unlock(vma);
1615 return error;
1616}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001617#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1618
Linus Torvalds1da177e2005-04-16 15:20:36 -07001619/*
1620 * vma is the first one with address < vma->vm_start. Have to extend vma.
1621 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001622static inline int expand_downwards(struct vm_area_struct *vma,
1623 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624{
1625 int error;
1626
1627 /*
1628 * We must make sure the anon_vma is allocated
1629 * so that the anon_vma locking is not a noop.
1630 */
1631 if (unlikely(anon_vma_prepare(vma)))
1632 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001633
1634 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001635 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001636 if (error)
1637 return error;
1638
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639 anon_vma_lock(vma);
1640
1641 /*
1642 * vma->vm_start/vm_end cannot change under us because the caller
1643 * is required to hold the mmap_sem in read mode. We need the
1644 * anon_vma lock to serialize against concurrent expand_stacks.
1645 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646
1647 /* Somebody else might have raced and expanded it already */
1648 if (address < vma->vm_start) {
1649 unsigned long size, grow;
1650
1651 size = vma->vm_end - address;
1652 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1653
1654 error = acct_stack_growth(vma, size, grow);
1655 if (!error) {
1656 vma->vm_start = address;
1657 vma->vm_pgoff -= grow;
1658 }
1659 }
1660 anon_vma_unlock(vma);
1661 return error;
1662}
1663
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001664int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1665{
1666 return expand_downwards(vma, address);
1667}
1668
1669#ifdef CONFIG_STACK_GROWSUP
1670int expand_stack(struct vm_area_struct *vma, unsigned long address)
1671{
1672 return expand_upwards(vma, address);
1673}
1674
1675struct vm_area_struct *
1676find_extend_vma(struct mm_struct *mm, unsigned long addr)
1677{
1678 struct vm_area_struct *vma, *prev;
1679
1680 addr &= PAGE_MASK;
1681 vma = find_vma_prev(mm, addr, &prev);
1682 if (vma && (vma->vm_start <= addr))
1683 return vma;
1684 if (!prev || expand_stack(prev, addr))
1685 return NULL;
1686 if (prev->vm_flags & VM_LOCKED)
1687 make_pages_present(addr, prev->vm_end);
1688 return prev;
1689}
1690#else
1691int expand_stack(struct vm_area_struct *vma, unsigned long address)
1692{
1693 return expand_downwards(vma, address);
1694}
1695
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696struct vm_area_struct *
1697find_extend_vma(struct mm_struct * mm, unsigned long addr)
1698{
1699 struct vm_area_struct * vma;
1700 unsigned long start;
1701
1702 addr &= PAGE_MASK;
1703 vma = find_vma(mm,addr);
1704 if (!vma)
1705 return NULL;
1706 if (vma->vm_start <= addr)
1707 return vma;
1708 if (!(vma->vm_flags & VM_GROWSDOWN))
1709 return NULL;
1710 start = vma->vm_start;
1711 if (expand_stack(vma, addr))
1712 return NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001713 if (vma->vm_flags & VM_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 make_pages_present(addr, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 return vma;
1716}
1717#endif
1718
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001720 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001722 *
1723 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001725static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001727 /* Update high watermark before we lower total_vm */
1728 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001730 long nrpages = vma_pages(vma);
1731
1732 mm->total_vm -= nrpages;
1733 if (vma->vm_flags & VM_LOCKED)
1734 mm->locked_vm -= nrpages;
1735 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001736 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001737 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738 validate_mm(mm);
1739}
1740
1741/*
1742 * Get rid of page table information in the indicated region.
1743 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001744 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745 */
1746static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001747 struct vm_area_struct *vma, struct vm_area_struct *prev,
1748 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001750 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 struct mmu_gather *tlb;
1752 unsigned long nr_accounted = 0;
1753
1754 lru_add_drain();
1755 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001756 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001757 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001759 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001760 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 tlb_finish_mmu(tlb, start, end);
1762}
1763
1764/*
1765 * Create a list of vma's touched by the unmap, removing them from the mm's
1766 * vma list as we go..
1767 */
1768static void
1769detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1770 struct vm_area_struct *prev, unsigned long end)
1771{
1772 struct vm_area_struct **insertion_point;
1773 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001774 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
1776 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1777 do {
1778 rb_erase(&vma->vm_rb, &mm->mm_rb);
1779 mm->map_count--;
1780 tail_vma = vma;
1781 vma = vma->vm_next;
1782 } while (vma && vma->vm_start < end);
1783 *insertion_point = vma;
1784 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001785 if (mm->unmap_area == arch_unmap_area)
1786 addr = prev ? prev->vm_end : mm->mmap_base;
1787 else
1788 addr = vma ? vma->vm_start : mm->mmap_base;
1789 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 mm->mmap_cache = NULL; /* Kill the cache. */
1791}
1792
1793/*
1794 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001795 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796 */
1797int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1798 unsigned long addr, int new_below)
1799{
1800 struct mempolicy *pol;
1801 struct vm_area_struct *new;
1802
1803 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1804 return -EINVAL;
1805
1806 if (mm->map_count >= sysctl_max_map_count)
1807 return -ENOMEM;
1808
Christoph Lametere94b1762006-12-06 20:33:17 -08001809 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 if (!new)
1811 return -ENOMEM;
1812
1813 /* most fields are the same, copy all, and then fixup */
1814 *new = *vma;
1815
1816 if (new_below)
1817 new->vm_end = addr;
1818 else {
1819 new->vm_start = addr;
1820 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1821 }
1822
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001823 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 if (IS_ERR(pol)) {
1825 kmem_cache_free(vm_area_cachep, new);
1826 return PTR_ERR(pol);
1827 }
1828 vma_set_policy(new, pol);
1829
Matt Helsley925d1c42008-04-29 01:01:36 -07001830 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001832 if (vma->vm_flags & VM_EXECUTABLE)
1833 added_exe_file_vma(mm);
1834 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835
1836 if (new->vm_ops && new->vm_ops->open)
1837 new->vm_ops->open(new);
1838
1839 if (new_below)
1840 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1841 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1842 else
1843 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1844
1845 return 0;
1846}
1847
1848/* Munmap is split into 2 main parts -- this part which finds
1849 * what needs doing, and the areas themselves, which do the
1850 * work. This now handles partial unmappings.
1851 * Jeremy Fitzhardinge <jeremy@goop.org>
1852 */
1853int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1854{
1855 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001856 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857
1858 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1859 return -EINVAL;
1860
1861 if ((len = PAGE_ALIGN(len)) == 0)
1862 return -EINVAL;
1863
1864 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001865 vma = find_vma_prev(mm, start, &prev);
1866 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001868 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869
1870 /* if it doesn't overlap, we have nothing.. */
1871 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001872 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 return 0;
1874
1875 /*
1876 * If we need to split any vma, do it now to save pain later.
1877 *
1878 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1879 * unmapped vm_area_struct will remain in use: so lower split_vma
1880 * places tmp vma above, and higher split_vma places tmp vma below.
1881 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001882 if (start > vma->vm_start) {
1883 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884 if (error)
1885 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001886 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 }
1888
1889 /* Does it split the last one? */
1890 last = find_vma(mm, end);
1891 if (last && end > last->vm_start) {
1892 int error = split_vma(mm, last, end, 1);
1893 if (error)
1894 return error;
1895 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001896 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897
1898 /*
1899 * Remove the vma's, and unmap the actual pages
1900 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001901 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1902 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903
1904 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001905 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906
1907 return 0;
1908}
1909
1910EXPORT_SYMBOL(do_munmap);
1911
1912asmlinkage long sys_munmap(unsigned long addr, size_t len)
1913{
1914 int ret;
1915 struct mm_struct *mm = current->mm;
1916
1917 profile_munmap(addr);
1918
1919 down_write(&mm->mmap_sem);
1920 ret = do_munmap(mm, addr, len);
1921 up_write(&mm->mmap_sem);
1922 return ret;
1923}
1924
1925static inline void verify_mm_writelocked(struct mm_struct *mm)
1926{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001927#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1929 WARN_ON(1);
1930 up_read(&mm->mmap_sem);
1931 }
1932#endif
1933}
1934
1935/*
1936 * this is really a simplified "do_mmap". it only handles
1937 * anonymous maps. eventually we may be able to do some
1938 * brk-specific accounting here.
1939 */
1940unsigned long do_brk(unsigned long addr, unsigned long len)
1941{
1942 struct mm_struct * mm = current->mm;
1943 struct vm_area_struct * vma, * prev;
1944 unsigned long flags;
1945 struct rb_node ** rb_link, * rb_parent;
1946 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001947 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948
1949 len = PAGE_ALIGN(len);
1950 if (!len)
1951 return addr;
1952
1953 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1954 return -EINVAL;
1955
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001956 if (is_hugepage_only_range(mm, addr, len))
1957 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001958
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001959 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05001960 if (error)
1961 return error;
1962
Kirill Korotaev3a459752006-09-07 14:17:04 +04001963 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1964
1965 error = arch_mmap_check(addr, len, flags);
1966 if (error)
1967 return error;
1968
Linus Torvalds1da177e2005-04-16 15:20:36 -07001969 /*
1970 * mlock MCL_FUTURE?
1971 */
1972 if (mm->def_flags & VM_LOCKED) {
1973 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001974 locked = len >> PAGE_SHIFT;
1975 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001977 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1979 return -EAGAIN;
1980 }
1981
1982 /*
1983 * mm->mmap_sem is required to protect against another thread
1984 * changing the mappings in case we sleep.
1985 */
1986 verify_mm_writelocked(mm);
1987
1988 /*
1989 * Clear old maps. this also does some error checking for us
1990 */
1991 munmap_back:
1992 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1993 if (vma && vma->vm_start < addr + len) {
1994 if (do_munmap(mm, addr, len))
1995 return -ENOMEM;
1996 goto munmap_back;
1997 }
1998
1999 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002000 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 return -ENOMEM;
2002
2003 if (mm->map_count > sysctl_max_map_count)
2004 return -ENOMEM;
2005
2006 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2007 return -ENOMEM;
2008
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009 /* Can we just expand an old private anonymous mapping? */
2010 if (vma_merge(mm, prev, addr, addr + len, flags,
2011 NULL, NULL, pgoff, NULL))
2012 goto out;
2013
2014 /*
2015 * create a vma struct for an anonymous mapping
2016 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002017 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002018 if (!vma) {
2019 vm_unacct_memory(len >> PAGE_SHIFT);
2020 return -ENOMEM;
2021 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022
2023 vma->vm_mm = mm;
2024 vma->vm_start = addr;
2025 vma->vm_end = addr + len;
2026 vma->vm_pgoff = pgoff;
2027 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002028 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002029 vma_link(mm, vma, prev, rb_link, rb_parent);
2030out:
2031 mm->total_vm += len >> PAGE_SHIFT;
2032 if (flags & VM_LOCKED) {
2033 mm->locked_vm += len >> PAGE_SHIFT;
2034 make_pages_present(addr, addr + len);
2035 }
2036 return addr;
2037}
2038
2039EXPORT_SYMBOL(do_brk);
2040
2041/* Release all mmaps. */
2042void exit_mmap(struct mm_struct *mm)
2043{
2044 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07002045 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002047 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002048
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002049 /* mm's last user has gone, and its about to be pulled down */
2050 arch_exit_mmap(mm);
2051
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002053 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002054 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002055 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002056 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002057 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002058 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002059 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002060 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002063 * Walk the list again, actually closing and freeing it,
2064 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002066 while (vma)
2067 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002068
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002069 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070}
2071
2072/* Insert vm structure into process list sorted by address
2073 * and into the inode's i_mmap tree. If vm_file is non-NULL
2074 * then i_mmap_lock is taken here.
2075 */
2076int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2077{
2078 struct vm_area_struct * __vma, * prev;
2079 struct rb_node ** rb_link, * rb_parent;
2080
2081 /*
2082 * The vm_pgoff of a purely anonymous vma should be irrelevant
2083 * until its first write fault, when page's anon_vma and index
2084 * are set. But now set the vm_pgoff it will almost certainly
2085 * end up with (unless mremap moves it elsewhere before that
2086 * first wfault), so /proc/pid/maps tells a consistent story.
2087 *
2088 * By setting it to reflect the virtual start address of the
2089 * vma, merges and splits can happen in a seamless way, just
2090 * using the existing file pgoff checks and manipulations.
2091 * Similarly in do_mmap_pgoff and in do_brk.
2092 */
2093 if (!vma->vm_file) {
2094 BUG_ON(vma->anon_vma);
2095 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2096 }
2097 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2098 if (__vma && __vma->vm_start < vma->vm_end)
2099 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002100 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002101 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002102 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103 vma_link(mm, vma, prev, rb_link, rb_parent);
2104 return 0;
2105}
2106
2107/*
2108 * Copy the vma structure to a new location in the same mm,
2109 * prior to moving page table entries, to effect an mremap move.
2110 */
2111struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2112 unsigned long addr, unsigned long len, pgoff_t pgoff)
2113{
2114 struct vm_area_struct *vma = *vmap;
2115 unsigned long vma_start = vma->vm_start;
2116 struct mm_struct *mm = vma->vm_mm;
2117 struct vm_area_struct *new_vma, *prev;
2118 struct rb_node **rb_link, *rb_parent;
2119 struct mempolicy *pol;
2120
2121 /*
2122 * If anonymous vma has not yet been faulted, update new pgoff
2123 * to match new location, to increase its chance of merging.
2124 */
2125 if (!vma->vm_file && !vma->anon_vma)
2126 pgoff = addr >> PAGE_SHIFT;
2127
2128 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2129 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2130 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2131 if (new_vma) {
2132 /*
2133 * Source vma may have been merged into new_vma
2134 */
2135 if (vma_start >= new_vma->vm_start &&
2136 vma_start < new_vma->vm_end)
2137 *vmap = new_vma;
2138 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002139 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140 if (new_vma) {
2141 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002142 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002143 if (IS_ERR(pol)) {
2144 kmem_cache_free(vm_area_cachep, new_vma);
2145 return NULL;
2146 }
2147 vma_set_policy(new_vma, pol);
2148 new_vma->vm_start = addr;
2149 new_vma->vm_end = addr + len;
2150 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002151 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002152 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002153 if (vma->vm_flags & VM_EXECUTABLE)
2154 added_exe_file_vma(mm);
2155 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 if (new_vma->vm_ops && new_vma->vm_ops->open)
2157 new_vma->vm_ops->open(new_vma);
2158 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2159 }
2160 }
2161 return new_vma;
2162}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002163
2164/*
2165 * Return true if the calling process may expand its vm space by the passed
2166 * number of pages
2167 */
2168int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2169{
2170 unsigned long cur = mm->total_vm; /* pages */
2171 unsigned long lim;
2172
2173 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2174
2175 if (cur + npages > lim)
2176 return 0;
2177 return 1;
2178}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002179
2180
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002181static int special_mapping_fault(struct vm_area_struct *vma,
2182 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002183{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002184 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002185 struct page **pages;
2186
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002187 /*
2188 * special mappings have no vm_file, and in that case, the mm
2189 * uses vm_pgoff internally. So we have to subtract it from here.
2190 * We are allowed to do this because we are the mm; do not copy
2191 * this code into drivers!
2192 */
2193 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002194
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002195 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2196 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002197
2198 if (*pages) {
2199 struct page *page = *pages;
2200 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002201 vmf->page = page;
2202 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002203 }
2204
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002205 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002206}
2207
2208/*
2209 * Having a close hook prevents vma merging regardless of flags.
2210 */
2211static void special_mapping_close(struct vm_area_struct *vma)
2212{
2213}
2214
2215static struct vm_operations_struct special_mapping_vmops = {
2216 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002217 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002218};
2219
2220/*
2221 * Called with mm->mmap_sem held for writing.
2222 * Insert a new vma covering the given region, with the given flags.
2223 * Its pages are supplied by the given array of struct page *.
2224 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2225 * The region past the last page supplied will always produce SIGBUS.
2226 * The array pointer and the pages it points to are assumed to stay alive
2227 * for as long as this mapping might exist.
2228 */
2229int install_special_mapping(struct mm_struct *mm,
2230 unsigned long addr, unsigned long len,
2231 unsigned long vm_flags, struct page **pages)
2232{
2233 struct vm_area_struct *vma;
2234
2235 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2236 if (unlikely(vma == NULL))
2237 return -ENOMEM;
2238
2239 vma->vm_mm = mm;
2240 vma->vm_start = addr;
2241 vma->vm_end = addr + len;
2242
Nick Piggin2f987352008-02-02 03:08:53 +01002243 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002244 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002245
2246 vma->vm_ops = &special_mapping_vmops;
2247 vma->vm_private_data = pages;
2248
2249 if (unlikely(insert_vm_struct(mm, vma))) {
2250 kmem_cache_free(vm_area_cachep, vma);
2251 return -ENOMEM;
2252 }
2253
2254 mm->total_vm += len >> PAGE_SHIFT;
2255
2256 return 0;
2257}