blob: 2ec8eb5a9cdd0b4ae2e20471858bd4e09d83af00 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
Alan Cox046c6882009-01-05 14:06:29 +00006 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
9#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070010#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070029#include <linux/mmu_notifier.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020030#include <linux/perf_event.h>
Al Viro120a7952010-10-30 02:54:44 -040031#include <linux/audit.h>
Andrea Arcangelib15d00b2011-01-13 15:46:59 -080032#include <linux/khugepaged.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#include <asm/uaccess.h>
35#include <asm/cacheflush.h>
36#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020037#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Jan Beulich42b77722008-07-23 21:27:10 -070039#include "internal.h"
40
Kirill Korotaev3a459752006-09-07 14:17:04 +040041#ifndef arch_mmap_check
42#define arch_mmap_check(addr, len, flags) (0)
43#endif
44
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080045#ifndef arch_rebalance_pgtables
46#define arch_rebalance_pgtables(addr, len) (addr)
47#endif
48
Hugh Dickinse0da3822005-04-19 13:29:15 -070049static void unmap_region(struct mm_struct *mm,
50 struct vm_area_struct *vma, struct vm_area_struct *prev,
51 unsigned long start, unsigned long end);
52
Linus Torvalds1da177e2005-04-16 15:20:36 -070053/*
54 * WARNING: the debugging will use recursive algorithms so never enable this
55 * unless you know what you are doing.
56 */
57#undef DEBUG_MM_RB
58
59/* description of effects of mapping type and prot in current implementation.
60 * this is due to the limited x86 page protection hardware. The expected
61 * behavior is in parens:
62 *
63 * map_type prot
64 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
65 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (yes) yes w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
70 * w: (no) no w: (no) no w: (copy) copy w: (no) no
71 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
72 *
73 */
74pgprot_t protection_map[16] = {
75 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
76 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
77};
78
Hugh Dickins804af2c2006-07-26 21:39:49 +010079pgprot_t vm_get_page_prot(unsigned long vm_flags)
80{
Dave Kleikampb845f312008-07-08 00:28:51 +100081 return __pgprot(pgprot_val(protection_map[vm_flags &
82 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
83 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010084}
85EXPORT_SYMBOL(vm_get_page_prot);
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
88int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070089int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -070090struct percpu_counter vm_committed_as;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92/*
93 * Check that a process has enough memory to allocate a new virtual
94 * mapping. 0 means there is enough memory for the allocation to
95 * succeed and -ENOMEM implies there is not.
96 *
97 * We currently support three overcommit policies, which are set via the
98 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
99 *
100 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
101 * Additional code 2002 Jul 20 by Robert Love.
102 *
103 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
104 *
105 * Note this is a helper function intended to be used by LSMs which
106 * wish to use this logic.
107 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700108int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109{
110 unsigned long free, allowed;
111
112 vm_acct_memory(pages);
113
114 /*
115 * Sometimes we want to use more memory than we have
116 */
117 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
118 return 0;
119
120 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
121 unsigned long n;
122
Christoph Lameter347ce432006-06-30 01:55:35 -0700123 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 free += nr_swap_pages;
125
126 /*
127 * Any slabs which are created with the
128 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
129 * which are reclaimable, under pressure. The dentry
130 * cache and most inode caches should fall into this
131 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700132 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
134 /*
135 * Leave the last 3% for root
136 */
137 if (!cap_sys_admin)
138 free -= free / 32;
139
140 if (free > pages)
141 return 0;
142
143 /*
144 * nr_free_pages() is very expensive on large systems,
145 * only call if we're about to fail.
146 */
147 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700148
149 /*
150 * Leave reserved pages. The pages are not for anonymous pages.
151 */
152 if (n <= totalreserve_pages)
153 goto error;
154 else
155 n -= totalreserve_pages;
156
157 /*
158 * Leave the last 3% for root
159 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 if (!cap_sys_admin)
161 n -= n / 32;
162 free += n;
163
164 if (free > pages)
165 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700166
167 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 }
169
170 allowed = (totalram_pages - hugetlb_total_pages())
171 * sysctl_overcommit_ratio / 100;
172 /*
173 * Leave the last 3% for root
174 */
175 if (!cap_sys_admin)
176 allowed -= allowed / 32;
177 allowed += total_swap_pages;
178
179 /* Don't let a single process grow too big:
180 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -0700181 if (mm)
182 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700184 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700186error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 vm_unacct_memory(pages);
188
189 return -ENOMEM;
190}
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192/*
193 * Requires inode->i_mapping->i_mmap_lock
194 */
195static void __remove_shared_vm_struct(struct vm_area_struct *vma,
196 struct file *file, struct address_space *mapping)
197{
198 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800199 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 if (vma->vm_flags & VM_SHARED)
201 mapping->i_mmap_writable--;
202
203 flush_dcache_mmap_lock(mapping);
204 if (unlikely(vma->vm_flags & VM_NONLINEAR))
205 list_del_init(&vma->shared.vm_set.list);
206 else
207 vma_prio_tree_remove(vma, &mapping->i_mmap);
208 flush_dcache_mmap_unlock(mapping);
209}
210
211/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700212 * Unlink a file-based vm structure from its prio_tree, to hide
213 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700215void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
217 struct file *file = vma->vm_file;
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (file) {
220 struct address_space *mapping = file->f_mapping;
221 spin_lock(&mapping->i_mmap_lock);
222 __remove_shared_vm_struct(vma, file, mapping);
223 spin_unlock(&mapping->i_mmap_lock);
224 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700225}
226
227/*
228 * Close a vm structure and free it, returning the next.
229 */
230static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
231{
232 struct vm_area_struct *next = vma->vm_next;
233
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700234 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 if (vma->vm_ops && vma->vm_ops->close)
236 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700237 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700238 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700239 if (vma->vm_flags & VM_EXECUTABLE)
240 removed_exe_file_vma(vma->vm_mm);
241 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700242 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700244 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245}
246
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100247SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248{
249 unsigned long rlim, retval;
250 unsigned long newbrk, oldbrk;
251 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700252 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 down_write(&mm->mmap_sem);
255
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700256#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800257 /*
258 * CONFIG_COMPAT_BRK can still be overridden by setting
259 * randomize_va_space to 2, which will still cause mm->start_brk
260 * to be arbitrarily shifted
261 */
262 if (mm->start_brk > PAGE_ALIGN(mm->end_data))
263 min_brk = mm->start_brk;
264 else
265 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700266#else
267 min_brk = mm->start_brk;
268#endif
269 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700271
272 /*
273 * Check against rlimit here. If this check is done later after the test
274 * of oldbrk with newbrk then it can escape the test and let the data
275 * segment grow beyond its set limit the in case where the limit is
276 * not page aligned -Ram Gupta
277 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800278 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100279 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
280 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700281 goto out;
282
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 newbrk = PAGE_ALIGN(brk);
284 oldbrk = PAGE_ALIGN(mm->brk);
285 if (oldbrk == newbrk)
286 goto set_brk;
287
288 /* Always allow shrinking brk. */
289 if (brk <= mm->brk) {
290 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
291 goto set_brk;
292 goto out;
293 }
294
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 /* Check against existing mmap mappings. */
296 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
297 goto out;
298
299 /* Ok, looks good - let it rip. */
300 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
301 goto out;
302set_brk:
303 mm->brk = brk;
304out:
305 retval = mm->brk;
306 up_write(&mm->mmap_sem);
307 return retval;
308}
309
310#ifdef DEBUG_MM_RB
311static int browse_rb(struct rb_root *root)
312{
313 int i = 0, j;
314 struct rb_node *nd, *pn = NULL;
315 unsigned long prev = 0, pend = 0;
316
317 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
318 struct vm_area_struct *vma;
319 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
320 if (vma->vm_start < prev)
321 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
322 if (vma->vm_start < pend)
323 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
324 if (vma->vm_start > vma->vm_end)
325 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
326 i++;
327 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800328 prev = vma->vm_start;
329 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 }
331 j = 0;
332 for (nd = pn; nd; nd = rb_prev(nd)) {
333 j++;
334 }
335 if (i != j)
336 printk("backwards %d, forwards %d\n", j, i), i = 0;
337 return i;
338}
339
340void validate_mm(struct mm_struct *mm)
341{
342 int bug = 0;
343 int i = 0;
344 struct vm_area_struct *tmp = mm->mmap;
345 while (tmp) {
346 tmp = tmp->vm_next;
347 i++;
348 }
349 if (i != mm->map_count)
350 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
351 i = browse_rb(&mm->mm_rb);
352 if (i != mm->map_count)
353 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200354 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355}
356#else
357#define validate_mm(mm) do { } while (0)
358#endif
359
360static struct vm_area_struct *
361find_vma_prepare(struct mm_struct *mm, unsigned long addr,
362 struct vm_area_struct **pprev, struct rb_node ***rb_link,
363 struct rb_node ** rb_parent)
364{
365 struct vm_area_struct * vma;
366 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
367
368 __rb_link = &mm->mm_rb.rb_node;
369 rb_prev = __rb_parent = NULL;
370 vma = NULL;
371
372 while (*__rb_link) {
373 struct vm_area_struct *vma_tmp;
374
375 __rb_parent = *__rb_link;
376 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
377
378 if (vma_tmp->vm_end > addr) {
379 vma = vma_tmp;
380 if (vma_tmp->vm_start <= addr)
Benny Halevydfe195f2008-08-05 13:01:41 -0700381 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 __rb_link = &__rb_parent->rb_left;
383 } else {
384 rb_prev = __rb_parent;
385 __rb_link = &__rb_parent->rb_right;
386 }
387 }
388
389 *pprev = NULL;
390 if (rb_prev)
391 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
392 *rb_link = __rb_link;
393 *rb_parent = __rb_parent;
394 return vma;
395}
396
397static inline void
398__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
399 struct vm_area_struct *prev, struct rb_node *rb_parent)
400{
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700401 struct vm_area_struct *next;
402
403 vma->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 if (prev) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700405 next = prev->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 prev->vm_next = vma;
407 } else {
408 mm->mmap = vma;
409 if (rb_parent)
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700410 next = rb_entry(rb_parent,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 struct vm_area_struct, vm_rb);
412 else
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700413 next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 }
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700415 vma->vm_next = next;
416 if (next)
417 next->vm_prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418}
419
420void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
421 struct rb_node **rb_link, struct rb_node *rb_parent)
422{
423 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
424 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
425}
426
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700427static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428{
ZhenwenXu48aae422009-01-06 14:40:21 -0800429 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
431 file = vma->vm_file;
432 if (file) {
433 struct address_space *mapping = file->f_mapping;
434
435 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800436 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 if (vma->vm_flags & VM_SHARED)
438 mapping->i_mmap_writable++;
439
440 flush_dcache_mmap_lock(mapping);
441 if (unlikely(vma->vm_flags & VM_NONLINEAR))
442 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
443 else
444 vma_prio_tree_insert(vma, &mapping->i_mmap);
445 flush_dcache_mmap_unlock(mapping);
446 }
447}
448
449static void
450__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
451 struct vm_area_struct *prev, struct rb_node **rb_link,
452 struct rb_node *rb_parent)
453{
454 __vma_link_list(mm, vma, prev, rb_parent);
455 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456}
457
458static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
459 struct vm_area_struct *prev, struct rb_node **rb_link,
460 struct rb_node *rb_parent)
461{
462 struct address_space *mapping = NULL;
463
464 if (vma->vm_file)
465 mapping = vma->vm_file->f_mapping;
466
467 if (mapping) {
468 spin_lock(&mapping->i_mmap_lock);
469 vma->vm_truncate_count = mapping->truncate_count;
470 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
472 __vma_link(mm, vma, prev, rb_link, rb_parent);
473 __vma_link_file(vma);
474
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (mapping)
476 spin_unlock(&mapping->i_mmap_lock);
477
478 mm->map_count++;
479 validate_mm(mm);
480}
481
482/*
483 * Helper for vma_adjust in the split_vma insert case:
484 * insert vm structure into list and rbtree and anon_vma,
485 * but it has already been inserted into prio_tree earlier.
486 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800487static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488{
ZhenwenXu48aae422009-01-06 14:40:21 -0800489 struct vm_area_struct *__vma, *prev;
490 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
492 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200493 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 __vma_link(mm, vma, prev, rb_link, rb_parent);
495 mm->map_count++;
496}
497
498static inline void
499__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
500 struct vm_area_struct *prev)
501{
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700502 struct vm_area_struct *next = vma->vm_next;
503
504 prev->vm_next = next;
505 if (next)
506 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 rb_erase(&vma->vm_rb, &mm->mm_rb);
508 if (mm->mmap_cache == vma)
509 mm->mmap_cache = prev;
510}
511
512/*
513 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
514 * is already present in an i_mmap tree without adjusting the tree.
515 * The following helper function should be used when such adjustments
516 * are necessary. The "insert" vma (if any) is to be inserted
517 * before we drop the necessary locks.
518 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800519int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
521{
522 struct mm_struct *mm = vma->vm_mm;
523 struct vm_area_struct *next = vma->vm_next;
524 struct vm_area_struct *importer = NULL;
525 struct address_space *mapping = NULL;
526 struct prio_tree_root *root = NULL;
Rik van Riel012f1802010-08-09 17:18:40 -0700527 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 struct file *file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 long adjust_next = 0;
530 int remove_next = 0;
531
532 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700533 struct vm_area_struct *exporter = NULL;
534
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 if (end >= next->vm_end) {
536 /*
537 * vma expands, overlapping all the next, and
538 * perhaps the one after too (mprotect case 6).
539 */
540again: remove_next = 1 + (end > next->vm_end);
541 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700542 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 importer = vma;
544 } else if (end > next->vm_start) {
545 /*
546 * vma expands, overlapping part of the next:
547 * mprotect case 5 shifting the boundary up.
548 */
549 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700550 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 importer = vma;
552 } else if (end < vma->vm_end) {
553 /*
554 * vma shrinks, and !insert tells it's not
555 * split_vma inserting another: so it must be
556 * mprotect case 4 shifting the boundary down.
557 */
558 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700559 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 importer = next;
561 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
Rik van Riel5beb4932010-03-05 13:42:07 -0800563 /*
564 * Easily overlooked: when mprotect shifts the boundary,
565 * make sure the expanding vma has anon_vma set if the
566 * shrinking vma had, to cover any anon pages imported.
567 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700568 if (exporter && exporter->anon_vma && !importer->anon_vma) {
569 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800570 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700571 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800572 }
573 }
574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 if (file) {
576 mapping = file->f_mapping;
577 if (!(vma->vm_flags & VM_NONLINEAR))
578 root = &mapping->i_mmap;
579 spin_lock(&mapping->i_mmap_lock);
580 if (importer &&
581 vma->vm_truncate_count != next->vm_truncate_count) {
582 /*
583 * unmap_mapping_range might be in progress:
584 * ensure that the expanding vma is rescanned.
585 */
586 importer->vm_truncate_count = 0;
587 }
588 if (insert) {
589 insert->vm_truncate_count = vma->vm_truncate_count;
590 /*
591 * Put into prio_tree now, so instantiated pages
592 * are visible to arm/parisc __flush_dcache_page
593 * throughout; but we cannot insert into address
594 * space until vma start or end is updated.
595 */
596 __vma_link_file(insert);
597 }
598 }
599
Andrea Arcangeli94fcc582011-01-13 15:47:08 -0800600 vma_adjust_trans_huge(vma, start, end, adjust_next);
601
Rik van Riel012f1802010-08-09 17:18:40 -0700602 /*
603 * When changing only vma->vm_end, we don't really need anon_vma
604 * lock. This is a fairly rare case by itself, but the anon_vma
605 * lock may be shared between many sibling processes. Skipping
606 * the lock for brk adjustments makes a difference sometimes.
607 */
608 if (vma->anon_vma && (insert || importer || start != vma->vm_start)) {
609 anon_vma = vma->anon_vma;
610 anon_vma_lock(anon_vma);
611 }
612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 if (root) {
614 flush_dcache_mmap_lock(mapping);
615 vma_prio_tree_remove(vma, root);
616 if (adjust_next)
617 vma_prio_tree_remove(next, root);
618 }
619
620 vma->vm_start = start;
621 vma->vm_end = end;
622 vma->vm_pgoff = pgoff;
623 if (adjust_next) {
624 next->vm_start += adjust_next << PAGE_SHIFT;
625 next->vm_pgoff += adjust_next;
626 }
627
628 if (root) {
629 if (adjust_next)
630 vma_prio_tree_insert(next, root);
631 vma_prio_tree_insert(vma, root);
632 flush_dcache_mmap_unlock(mapping);
633 }
634
635 if (remove_next) {
636 /*
637 * vma_merge has merged next into vma, and needs
638 * us to remove next before dropping the locks.
639 */
640 __vma_unlink(mm, next, vma);
641 if (file)
642 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 } else if (insert) {
644 /*
645 * split_vma has split insert from vma, and needs
646 * us to insert it before dropping the locks
647 * (it may either follow vma or precede it).
648 */
649 __insert_vm_struct(mm, insert);
650 }
651
Rik van Riel012f1802010-08-09 17:18:40 -0700652 if (anon_vma)
653 anon_vma_unlock(anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 if (mapping)
655 spin_unlock(&mapping->i_mmap_lock);
656
657 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700658 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700660 if (next->vm_flags & VM_EXECUTABLE)
661 removed_exe_file_vma(mm);
662 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800663 if (next->anon_vma)
664 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700666 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 kmem_cache_free(vm_area_cachep, next);
668 /*
669 * In mprotect's case 6 (see comments on vma_merge),
670 * we must remove another next too. It would clutter
671 * up the code too much to do both in one go.
672 */
673 if (remove_next == 2) {
674 next = vma->vm_next;
675 goto again;
676 }
677 }
678
679 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800680
681 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682}
683
684/*
685 * If the vma has a ->close operation then the driver probably needs to release
686 * per-vma resources, so we don't attempt to merge those.
687 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688static inline int is_mergeable_vma(struct vm_area_struct *vma,
689 struct file *file, unsigned long vm_flags)
690{
Hugh Dickins8314c4f2009-09-21 17:02:25 -0700691 /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
692 if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 return 0;
694 if (vma->vm_file != file)
695 return 0;
696 if (vma->vm_ops && vma->vm_ops->close)
697 return 0;
698 return 1;
699}
700
701static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
702 struct anon_vma *anon_vma2)
703{
704 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
705}
706
707/*
708 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
709 * in front of (at a lower 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 *
714 * We don't check here for the merged mmap wrapping around the end of pagecache
715 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
716 * wrap, nor mmaps which cover the final page at index -1UL.
717 */
718static int
719can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
720 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
721{
722 if (is_mergeable_vma(vma, file, vm_flags) &&
723 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
724 if (vma->vm_pgoff == vm_pgoff)
725 return 1;
726 }
727 return 0;
728}
729
730/*
731 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
732 * beyond (at a higher virtual address and file offset than) the vma.
733 *
734 * We cannot merge two vmas if they have differently assigned (non-NULL)
735 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
736 */
737static int
738can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
739 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
740{
741 if (is_mergeable_vma(vma, file, vm_flags) &&
742 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
743 pgoff_t vm_pglen;
744 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
745 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
746 return 1;
747 }
748 return 0;
749}
750
751/*
752 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
753 * whether that can be merged with its predecessor or its successor.
754 * Or both (it neatly fills a hole).
755 *
756 * In most cases - when called for mmap, brk or mremap - [addr,end) is
757 * certain not to be mapped by the time vma_merge is called; but when
758 * called for mprotect, it is certain to be already mapped (either at
759 * an offset within prev, or at the start of next), and the flags of
760 * this area are about to be changed to vm_flags - and the no-change
761 * case has already been eliminated.
762 *
763 * The following mprotect cases have to be considered, where AAAA is
764 * the area passed down from mprotect_fixup, never extending beyond one
765 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
766 *
767 * AAAA AAAA AAAA AAAA
768 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
769 * cannot merge might become might become might become
770 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
771 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
772 * mremap move: PPPPNNNNNNNN 8
773 * AAAA
774 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
775 * might become case 1 below case 2 below case 3 below
776 *
777 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
778 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
779 */
780struct vm_area_struct *vma_merge(struct mm_struct *mm,
781 struct vm_area_struct *prev, unsigned long addr,
782 unsigned long end, unsigned long vm_flags,
783 struct anon_vma *anon_vma, struct file *file,
784 pgoff_t pgoff, struct mempolicy *policy)
785{
786 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
787 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800788 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789
790 /*
791 * We later require that vma->vm_flags == vm_flags,
792 * so this tests vma->vm_flags & VM_SPECIAL, too.
793 */
794 if (vm_flags & VM_SPECIAL)
795 return NULL;
796
797 if (prev)
798 next = prev->vm_next;
799 else
800 next = mm->mmap;
801 area = next;
802 if (next && next->vm_end == end) /* cases 6, 7, 8 */
803 next = next->vm_next;
804
805 /*
806 * Can it merge with the predecessor?
807 */
808 if (prev && prev->vm_end == addr &&
809 mpol_equal(vma_policy(prev), policy) &&
810 can_vma_merge_after(prev, vm_flags,
811 anon_vma, file, pgoff)) {
812 /*
813 * OK, it can. Can we now merge in the successor as well?
814 */
815 if (next && end == next->vm_start &&
816 mpol_equal(policy, vma_policy(next)) &&
817 can_vma_merge_before(next, vm_flags,
818 anon_vma, file, pgoff+pglen) &&
819 is_mergeable_anon_vma(prev->anon_vma,
820 next->anon_vma)) {
821 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800822 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 next->vm_end, prev->vm_pgoff, NULL);
824 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800825 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800827 if (err)
828 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -0800829 khugepaged_enter_vma_merge(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 return prev;
831 }
832
833 /*
834 * Can this new request be merged in front of next?
835 */
836 if (next && end == next->vm_start &&
837 mpol_equal(policy, vma_policy(next)) &&
838 can_vma_merge_before(next, vm_flags,
839 anon_vma, file, pgoff+pglen)) {
840 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800841 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 addr, prev->vm_pgoff, NULL);
843 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800844 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800846 if (err)
847 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -0800848 khugepaged_enter_vma_merge(area);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 return area;
850 }
851
852 return NULL;
853}
854
855/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700856 * Rough compatbility check to quickly see if it's even worth looking
857 * at sharing an anon_vma.
858 *
859 * They need to have the same vm_file, and the flags can only differ
860 * in things that mprotect may change.
861 *
862 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
863 * we can merge the two vma's. For example, we refuse to merge a vma if
864 * there is a vm_ops->close() function, because that indicates that the
865 * driver is doing some kind of reference counting. But that doesn't
866 * really matter for the anon_vma sharing case.
867 */
868static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
869{
870 return a->vm_end == b->vm_start &&
871 mpol_equal(vma_policy(a), vma_policy(b)) &&
872 a->vm_file == b->vm_file &&
873 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
874 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
875}
876
877/*
878 * Do some basic sanity checking to see if we can re-use the anon_vma
879 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
880 * the same as 'old', the other will be the new one that is trying
881 * to share the anon_vma.
882 *
883 * NOTE! This runs with mm_sem held for reading, so it is possible that
884 * the anon_vma of 'old' is concurrently in the process of being set up
885 * by another page fault trying to merge _that_. But that's ok: if it
886 * is being set up, that automatically means that it will be a singleton
887 * acceptable for merging, so we can do all of this optimistically. But
888 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
889 *
890 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
891 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
892 * is to return an anon_vma that is "complex" due to having gone through
893 * a fork).
894 *
895 * We also make sure that the two vma's are compatible (adjacent,
896 * and with the same memory policies). That's all stable, even with just
897 * a read lock on the mm_sem.
898 */
899static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
900{
901 if (anon_vma_compatible(a, b)) {
902 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
903
904 if (anon_vma && list_is_singular(&old->anon_vma_chain))
905 return anon_vma;
906 }
907 return NULL;
908}
909
910/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
912 * neighbouring vmas for a suitable anon_vma, before it goes off
913 * to allocate a new anon_vma. It checks because a repetitive
914 * sequence of mprotects and faults may otherwise lead to distinct
915 * anon_vmas being allocated, preventing vma merge in subsequent
916 * mprotect.
917 */
918struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
919{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700920 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
923 near = vma->vm_next;
924 if (!near)
925 goto try_prev;
926
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700927 anon_vma = reusable_anon_vma(near, vma, near);
928 if (anon_vma)
929 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930try_prev:
931 /*
932 * It is potentially slow to have to call find_vma_prev here.
933 * But it's only on the first write fault on the vma, not
934 * every time, and we could devise a way to avoid it later
935 * (e.g. stash info in next's anon_vma_node when assigning
936 * an anon_vma, or when trying vma_merge). Another time.
937 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200938 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 if (!near)
940 goto none;
941
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700942 anon_vma = reusable_anon_vma(near, near, vma);
943 if (anon_vma)
944 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945none:
946 /*
947 * There's no absolute need to look only at touching neighbours:
948 * we could search further afield for "compatible" anon_vmas.
949 * But it would probably just be a waste of time searching,
950 * or lead to too many vmas hanging off the same anon_vma.
951 * We're trying to allow mprotect remerging later on,
952 * not trying to minimize memory used for anon_vmas.
953 */
954 return NULL;
955}
956
957#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700958void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 struct file *file, long pages)
960{
961 const unsigned long stack_flags
962 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
963
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 if (file) {
965 mm->shared_vm += pages;
966 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
967 mm->exec_vm += pages;
968 } else if (flags & stack_flags)
969 mm->stack_vm += pages;
970 if (flags & (VM_RESERVED|VM_IO))
971 mm->reserved_vm += pages;
972}
973#endif /* CONFIG_PROC_FS */
974
975/*
Jianjun Kong27f5de72009-09-17 19:26:26 -0700976 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 */
978
ZhenwenXu48aae422009-01-06 14:40:21 -0800979unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 unsigned long len, unsigned long prot,
981 unsigned long flags, unsigned long pgoff)
982{
983 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 struct inode *inode;
985 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 int error;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700987 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 /*
990 * Does the application expect PROT_READ to imply PROT_EXEC?
991 *
992 * (the exception is when the underlying filesystem is noexec
993 * mounted, in which case we dont add PROT_EXEC.)
994 */
995 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800996 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 prot |= PROT_EXEC;
998
999 if (!len)
1000 return -EINVAL;
1001
Eric Paris7cd94142007-11-26 18:47:40 -05001002 if (!(flags & MAP_FIXED))
1003 addr = round_hint_to_min(addr);
1004
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 /* Careful about overflows.. */
1006 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -05001007 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 return -ENOMEM;
1009
1010 /* offset overflow? */
1011 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1012 return -EOVERFLOW;
1013
1014 /* Too many mappings? */
1015 if (mm->map_count > sysctl_max_map_count)
1016 return -ENOMEM;
1017
1018 /* Obtain the address to map to. we verify (or select) it and ensure
1019 * that it represents a valid section of the address space.
1020 */
1021 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1022 if (addr & ~PAGE_MASK)
1023 return addr;
1024
1025 /* Do simple checking here so the lower-level routines won't have
1026 * to. we assume access permissions have been handled by the open
1027 * of the memory object, so we don't do any here.
1028 */
1029 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1030 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1031
Huang Shijiecdf7b342009-09-21 17:03:36 -07001032 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 if (!can_do_mlock())
1034 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001035
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 /* mlock MCL_FUTURE? */
1037 if (vm_flags & VM_LOCKED) {
1038 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001039 locked = len >> PAGE_SHIFT;
1040 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001041 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001042 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1044 return -EAGAIN;
1045 }
1046
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001047 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048
1049 if (file) {
1050 switch (flags & MAP_TYPE) {
1051 case MAP_SHARED:
1052 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1053 return -EACCES;
1054
1055 /*
1056 * Make sure we don't allow writing to an append-only
1057 * file..
1058 */
1059 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1060 return -EACCES;
1061
1062 /*
1063 * Make sure there are no mandatory locks on the file.
1064 */
1065 if (locks_verify_locked(inode))
1066 return -EAGAIN;
1067
1068 vm_flags |= VM_SHARED | VM_MAYSHARE;
1069 if (!(file->f_mode & FMODE_WRITE))
1070 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1071
1072 /* fall through */
1073 case MAP_PRIVATE:
1074 if (!(file->f_mode & FMODE_READ))
1075 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001076 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001077 if (vm_flags & VM_EXEC)
1078 return -EPERM;
1079 vm_flags &= ~VM_MAYEXEC;
1080 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001081
1082 if (!file->f_op || !file->f_op->mmap)
1083 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 break;
1085
1086 default:
1087 return -EINVAL;
1088 }
1089 } else {
1090 switch (flags & MAP_TYPE) {
1091 case MAP_SHARED:
Tejun Heoce363942008-09-03 16:09:47 +02001092 /*
1093 * Ignore pgoff.
1094 */
1095 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 vm_flags |= VM_SHARED | VM_MAYSHARE;
1097 break;
1098 case MAP_PRIVATE:
1099 /*
1100 * Set pgoff according to addr for anon_vma.
1101 */
1102 pgoff = addr >> PAGE_SHIFT;
1103 break;
1104 default:
1105 return -EINVAL;
1106 }
1107 }
1108
Eric Parised032182007-06-28 15:55:21 -04001109 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 if (error)
1111 return error;
Eric Parised032182007-06-28 15:55:21 -04001112
Mel Gorman5a6fe122009-02-10 14:02:27 +00001113 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001114}
1115EXPORT_SYMBOL(do_mmap_pgoff);
1116
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001117SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1118 unsigned long, prot, unsigned long, flags,
1119 unsigned long, fd, unsigned long, pgoff)
1120{
1121 struct file *file = NULL;
1122 unsigned long retval = -EBADF;
1123
1124 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001125 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001126 if (unlikely(flags & MAP_HUGETLB))
1127 return -EINVAL;
1128 file = fget(fd);
1129 if (!file)
1130 goto out;
1131 } else if (flags & MAP_HUGETLB) {
1132 struct user_struct *user = NULL;
1133 /*
1134 * VM_NORESERVE is used because the reservations will be
1135 * taken when vm_ops->mmap() is called
1136 * A dummy user value is used because we are not locking
1137 * memory so no accounting is necessary
1138 */
1139 len = ALIGN(len, huge_page_size(&default_hstate));
1140 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
1141 &user, HUGETLB_ANONHUGE_INODE);
1142 if (IS_ERR(file))
1143 return PTR_ERR(file);
1144 }
1145
1146 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1147
1148 down_write(&current->mm->mmap_sem);
1149 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1150 up_write(&current->mm->mmap_sem);
1151
1152 if (file)
1153 fput(file);
1154out:
1155 return retval;
1156}
1157
Christoph Hellwiga4679372010-03-10 15:21:15 -08001158#ifdef __ARCH_WANT_SYS_OLD_MMAP
1159struct mmap_arg_struct {
1160 unsigned long addr;
1161 unsigned long len;
1162 unsigned long prot;
1163 unsigned long flags;
1164 unsigned long fd;
1165 unsigned long offset;
1166};
1167
1168SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1169{
1170 struct mmap_arg_struct a;
1171
1172 if (copy_from_user(&a, arg, sizeof(a)))
1173 return -EFAULT;
1174 if (a.offset & ~PAGE_MASK)
1175 return -EINVAL;
1176
1177 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1178 a.offset >> PAGE_SHIFT);
1179}
1180#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1181
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001182/*
1183 * Some shared mappigns will want the pages marked read-only
1184 * to track write events. If so, we'll downgrade vm_page_prot
1185 * to the private version (using protection_map[] without the
1186 * VM_SHARED bit).
1187 */
1188int vma_wants_writenotify(struct vm_area_struct *vma)
1189{
1190 unsigned int vm_flags = vma->vm_flags;
1191
1192 /* If it was private or non-writable, the write bit is already clear */
1193 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1194 return 0;
1195
1196 /* The backer wishes to know when pages are first written to? */
1197 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1198 return 1;
1199
1200 /* The open routine did something to the protections already? */
1201 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001202 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001203 return 0;
1204
1205 /* Specialty mapping? */
1206 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1207 return 0;
1208
1209 /* Can the mapping track the dirty pages? */
1210 return vma->vm_file && vma->vm_file->f_mapping &&
1211 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1212}
1213
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001214/*
1215 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001216 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001217 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001218static inline int accountable_mapping(struct file *file, unsigned int vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001219{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001220 /*
1221 * hugetlb has its own accounting separate from the core VM
1222 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1223 */
1224 if (file && is_file_hugepages(file))
1225 return 0;
1226
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001227 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1228}
1229
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001230unsigned long mmap_region(struct file *file, unsigned long addr,
1231 unsigned long len, unsigned long flags,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001232 unsigned int vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001233{
1234 struct mm_struct *mm = current->mm;
1235 struct vm_area_struct *vma, *prev;
1236 int correct_wcount = 0;
1237 int error;
1238 struct rb_node **rb_link, *rb_parent;
1239 unsigned long charged = 0;
1240 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1241
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 /* Clear old maps */
1243 error = -ENOMEM;
1244munmap_back:
1245 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1246 if (vma && vma->vm_start < addr + len) {
1247 if (do_munmap(mm, addr, len))
1248 return -ENOMEM;
1249 goto munmap_back;
1250 }
1251
1252 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001253 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 return -ENOMEM;
1255
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001256 /*
1257 * Set 'VM_NORESERVE' if we should not account for the
Mel Gorman5a6fe122009-02-10 14:02:27 +00001258 * memory use of this mapping.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001259 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001260 if ((flags & MAP_NORESERVE)) {
1261 /* We honor MAP_NORESERVE if allowed to overcommit */
1262 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1263 vm_flags |= VM_NORESERVE;
1264
1265 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1266 if (file && is_file_hugepages(file))
1267 vm_flags |= VM_NORESERVE;
1268 }
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001269
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001270 /*
1271 * Private writable mapping: check memory availability
1272 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001273 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001274 charged = len >> PAGE_SHIFT;
1275 if (security_vm_enough_memory(charged))
1276 return -ENOMEM;
1277 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 }
1279
1280 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001281 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001283 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1284 if (vma)
1285 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286
1287 /*
1288 * Determine the object being mapped and call the appropriate
1289 * specific mapper. the address has already been validated, but
1290 * not unmapped, but the maps are removed from the list.
1291 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001292 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 if (!vma) {
1294 error = -ENOMEM;
1295 goto unacct_error;
1296 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297
1298 vma->vm_mm = mm;
1299 vma->vm_start = addr;
1300 vma->vm_end = addr + len;
1301 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001302 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001304 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305
1306 if (file) {
1307 error = -EINVAL;
1308 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1309 goto free_vma;
1310 if (vm_flags & VM_DENYWRITE) {
1311 error = deny_write_access(file);
1312 if (error)
1313 goto free_vma;
1314 correct_wcount = 1;
1315 }
1316 vma->vm_file = file;
1317 get_file(file);
1318 error = file->f_op->mmap(file, vma);
1319 if (error)
1320 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001321 if (vm_flags & VM_EXECUTABLE)
1322 added_exe_file_vma(mm);
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001323
1324 /* Can addr have changed??
1325 *
1326 * Answer: Yes, several device drivers can do it in their
1327 * f_op->mmap method. -DaveM
1328 */
1329 addr = vma->vm_start;
1330 pgoff = vma->vm_pgoff;
1331 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 } else if (vm_flags & VM_SHARED) {
1333 error = shmem_zero_setup(vma);
1334 if (error)
1335 goto free_vma;
1336 }
1337
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001338 if (vma_wants_writenotify(vma)) {
1339 pgprot_t pprot = vma->vm_page_prot;
1340
1341 /* Can vma->vm_page_prot have changed??
1342 *
1343 * Answer: Yes, drivers may have changed it in their
1344 * f_op->mmap method.
1345 *
1346 * Ensures that vmas marked as uncached stay that way.
1347 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001348 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001349 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1350 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1351 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001352
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001353 vma_link(mm, vma, prev, rb_link, rb_parent);
1354 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001355
1356 /* Once vma denies write, undo our temporary denial count */
1357 if (correct_wcount)
1358 atomic_inc(&inode->i_writecount);
1359out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001360 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001361
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001363 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 if (vm_flags & VM_LOCKED) {
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001365 if (!mlock_vma_pages_range(vma, addr, addr + len))
1366 mm->locked_vm += (len >> PAGE_SHIFT);
Rik van Rielba470de2008-10-18 20:26:50 -07001367 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
Nick Piggin54cb8822007-07-19 01:46:59 -07001368 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 return addr;
1370
1371unmap_and_free_vma:
1372 if (correct_wcount)
1373 atomic_inc(&inode->i_writecount);
1374 vma->vm_file = NULL;
1375 fput(file);
1376
1377 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001378 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1379 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380free_vma:
1381 kmem_cache_free(vm_area_cachep, vma);
1382unacct_error:
1383 if (charged)
1384 vm_unacct_memory(charged);
1385 return error;
1386}
1387
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388/* Get an address range which is currently unmapped.
1389 * For shmat() with addr=0.
1390 *
1391 * Ugly calling convention alert:
1392 * Return value with the low bits set means error value,
1393 * ie
1394 * if (ret & ~PAGE_MASK)
1395 * error = ret;
1396 *
1397 * This function "knows" that -ENOMEM has the bits set.
1398 */
1399#ifndef HAVE_ARCH_UNMAPPED_AREA
1400unsigned long
1401arch_get_unmapped_area(struct file *filp, unsigned long addr,
1402 unsigned long len, unsigned long pgoff, unsigned long flags)
1403{
1404 struct mm_struct *mm = current->mm;
1405 struct vm_area_struct *vma;
1406 unsigned long start_addr;
1407
1408 if (len > TASK_SIZE)
1409 return -ENOMEM;
1410
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001411 if (flags & MAP_FIXED)
1412 return addr;
1413
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 if (addr) {
1415 addr = PAGE_ALIGN(addr);
1416 vma = find_vma(mm, addr);
1417 if (TASK_SIZE - len >= addr &&
1418 (!vma || addr + len <= vma->vm_start))
1419 return addr;
1420 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001421 if (len > mm->cached_hole_size) {
1422 start_addr = addr = mm->free_area_cache;
1423 } else {
1424 start_addr = addr = TASK_UNMAPPED_BASE;
1425 mm->cached_hole_size = 0;
1426 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427
1428full_search:
1429 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1430 /* At this point: (!vma || addr < vma->vm_end). */
1431 if (TASK_SIZE - len < addr) {
1432 /*
1433 * Start a new search - just in case we missed
1434 * some holes.
1435 */
1436 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001437 addr = TASK_UNMAPPED_BASE;
1438 start_addr = addr;
1439 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 goto full_search;
1441 }
1442 return -ENOMEM;
1443 }
1444 if (!vma || addr + len <= vma->vm_start) {
1445 /*
1446 * Remember the place where we stopped the search:
1447 */
1448 mm->free_area_cache = addr + len;
1449 return addr;
1450 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001451 if (addr + mm->cached_hole_size < vma->vm_start)
1452 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 addr = vma->vm_end;
1454 }
1455}
1456#endif
1457
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001458void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459{
1460 /*
1461 * Is this a new hole at the lowest possible address?
1462 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001463 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1464 mm->free_area_cache = addr;
1465 mm->cached_hole_size = ~0UL;
1466 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467}
1468
1469/*
1470 * This mmap-allocator allocates new areas top-down from below the
1471 * stack's low limit (the base):
1472 */
1473#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1474unsigned long
1475arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1476 const unsigned long len, const unsigned long pgoff,
1477 const unsigned long flags)
1478{
1479 struct vm_area_struct *vma;
1480 struct mm_struct *mm = current->mm;
1481 unsigned long addr = addr0;
1482
1483 /* requested length too big for entire address space */
1484 if (len > TASK_SIZE)
1485 return -ENOMEM;
1486
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001487 if (flags & MAP_FIXED)
1488 return addr;
1489
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 /* requesting a specific address */
1491 if (addr) {
1492 addr = PAGE_ALIGN(addr);
1493 vma = find_vma(mm, addr);
1494 if (TASK_SIZE - len >= addr &&
1495 (!vma || addr + len <= vma->vm_start))
1496 return addr;
1497 }
1498
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001499 /* check if free_area_cache is useful for us */
1500 if (len <= mm->cached_hole_size) {
1501 mm->cached_hole_size = 0;
1502 mm->free_area_cache = mm->mmap_base;
1503 }
1504
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 /* either no address requested or can't fit in requested address hole */
1506 addr = mm->free_area_cache;
1507
1508 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001509 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 vma = find_vma(mm, addr-len);
1511 if (!vma || addr <= vma->vm_start)
1512 /* remember the address as a hint for next time */
1513 return (mm->free_area_cache = addr-len);
1514 }
1515
Chris Wright73219d12005-06-21 17:14:52 -07001516 if (mm->mmap_base < len)
1517 goto bottomup;
1518
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 addr = mm->mmap_base-len;
1520
1521 do {
1522 /*
1523 * Lookup failure means no vma is above this address,
1524 * else if new region fits below vma->vm_start,
1525 * return with success:
1526 */
1527 vma = find_vma(mm, addr);
1528 if (!vma || addr+len <= vma->vm_start)
1529 /* remember the address as a hint for next time */
1530 return (mm->free_area_cache = addr);
1531
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001532 /* remember the largest hole we saw so far */
1533 if (addr + mm->cached_hole_size < vma->vm_start)
1534 mm->cached_hole_size = vma->vm_start - addr;
1535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 /* try just below the current vma->vm_start */
1537 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001538 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539
Chris Wright73219d12005-06-21 17:14:52 -07001540bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 /*
1542 * A failed mmap() very likely causes application failure,
1543 * so fall back to the bottom-up function here. This scenario
1544 * can happen with large stack limits and large mmap()
1545 * allocations.
1546 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001547 mm->cached_hole_size = ~0UL;
1548 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1550 /*
1551 * Restore the topdown base:
1552 */
1553 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001554 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555
1556 return addr;
1557}
1558#endif
1559
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001560void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561{
1562 /*
1563 * Is this a new hole at the highest possible address?
1564 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001565 if (addr > mm->free_area_cache)
1566 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567
1568 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001569 if (mm->free_area_cache > mm->mmap_base)
1570 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571}
1572
1573unsigned long
1574get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1575 unsigned long pgoff, unsigned long flags)
1576{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001577 unsigned long (*get_area)(struct file *, unsigned long,
1578 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579
Al Viro9206de92009-12-03 15:23:11 -05001580 unsigned long error = arch_mmap_check(addr, len, flags);
1581 if (error)
1582 return error;
1583
1584 /* Careful about overflows.. */
1585 if (len > TASK_SIZE)
1586 return -ENOMEM;
1587
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001588 get_area = current->mm->get_unmapped_area;
1589 if (file && file->f_op && file->f_op->get_unmapped_area)
1590 get_area = file->f_op->get_unmapped_area;
1591 addr = get_area(file, addr, len, pgoff, flags);
1592 if (IS_ERR_VALUE(addr))
1593 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001595 if (addr > TASK_SIZE - len)
1596 return -ENOMEM;
1597 if (addr & ~PAGE_MASK)
1598 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001599
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001600 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601}
1602
1603EXPORT_SYMBOL(get_unmapped_area);
1604
1605/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001606struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607{
1608 struct vm_area_struct *vma = NULL;
1609
1610 if (mm) {
1611 /* Check the cache first. */
1612 /* (Cache hit rate is typically around 35%.) */
1613 vma = mm->mmap_cache;
1614 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1615 struct rb_node * rb_node;
1616
1617 rb_node = mm->mm_rb.rb_node;
1618 vma = NULL;
1619
1620 while (rb_node) {
1621 struct vm_area_struct * vma_tmp;
1622
1623 vma_tmp = rb_entry(rb_node,
1624 struct vm_area_struct, vm_rb);
1625
1626 if (vma_tmp->vm_end > addr) {
1627 vma = vma_tmp;
1628 if (vma_tmp->vm_start <= addr)
1629 break;
1630 rb_node = rb_node->rb_left;
1631 } else
1632 rb_node = rb_node->rb_right;
1633 }
1634 if (vma)
1635 mm->mmap_cache = vma;
1636 }
1637 }
1638 return vma;
1639}
1640
1641EXPORT_SYMBOL(find_vma);
1642
1643/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1644struct vm_area_struct *
1645find_vma_prev(struct mm_struct *mm, unsigned long addr,
1646 struct vm_area_struct **pprev)
1647{
1648 struct vm_area_struct *vma = NULL, *prev = NULL;
ZhenwenXu48aae422009-01-06 14:40:21 -08001649 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001650 if (!mm)
1651 goto out;
1652
1653 /* Guard against addr being lower than the first VMA */
1654 vma = mm->mmap;
1655
1656 /* Go through the RB tree quickly. */
1657 rb_node = mm->mm_rb.rb_node;
1658
1659 while (rb_node) {
1660 struct vm_area_struct *vma_tmp;
1661 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1662
1663 if (addr < vma_tmp->vm_end) {
1664 rb_node = rb_node->rb_left;
1665 } else {
1666 prev = vma_tmp;
1667 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1668 break;
1669 rb_node = rb_node->rb_right;
1670 }
1671 }
1672
1673out:
1674 *pprev = prev;
1675 return prev ? prev->vm_next : vma;
1676}
1677
1678/*
1679 * Verify that the stack growth is acceptable and
1680 * update accounting. This is shared with both the
1681 * grow-up and grow-down cases.
1682 */
ZhenwenXu48aae422009-01-06 14:40:21 -08001683static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684{
1685 struct mm_struct *mm = vma->vm_mm;
1686 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001687 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688
1689 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001690 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 return -ENOMEM;
1692
1693 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08001694 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695 return -ENOMEM;
1696
1697 /* mlock limit tests */
1698 if (vma->vm_flags & VM_LOCKED) {
1699 unsigned long locked;
1700 unsigned long limit;
1701 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001702 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
1703 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704 if (locked > limit && !capable(CAP_IPC_LOCK))
1705 return -ENOMEM;
1706 }
1707
Adam Litke0d59a012007-01-30 14:35:39 -08001708 /* Check to ensure the stack will not grow into a hugetlb-only region */
1709 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1710 vma->vm_end - size;
1711 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1712 return -EFAULT;
1713
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 /*
1715 * Overcommit.. This must be the final test, as it will
1716 * update security statistics.
1717 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01001718 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 return -ENOMEM;
1720
1721 /* Ok, everything looks good - let it rip */
1722 mm->total_vm += grow;
1723 if (vma->vm_flags & VM_LOCKED)
1724 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001725 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 return 0;
1727}
1728
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001729#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001731 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1732 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001734int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735{
1736 int error;
1737
1738 if (!(vma->vm_flags & VM_GROWSUP))
1739 return -EFAULT;
1740
1741 /*
1742 * We must make sure the anon_vma is allocated
1743 * so that the anon_vma locking is not a noop.
1744 */
1745 if (unlikely(anon_vma_prepare(vma)))
1746 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07001747 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748
1749 /*
1750 * vma->vm_start/vm_end cannot change under us because the caller
1751 * is required to hold the mmap_sem in read mode. We need the
1752 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001753 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 */
Helge Deller06b32f32006-12-19 19:28:33 +01001755 if (address < PAGE_ALIGN(address+4))
1756 address = PAGE_ALIGN(address+4);
1757 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07001758 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01001759 return -ENOMEM;
1760 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 error = 0;
1762
1763 /* Somebody else might have raced and expanded it already */
1764 if (address > vma->vm_end) {
1765 unsigned long size, grow;
1766
1767 size = address - vma->vm_start;
1768 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1769
1770 error = acct_stack_growth(vma, size, grow);
Eric B Munson3af9e852010-05-18 15:30:49 +01001771 if (!error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 vma->vm_end = address;
Eric B Munson3af9e852010-05-18 15:30:49 +01001773 perf_event_mmap(vma);
1774 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001776 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001777 khugepaged_enter_vma_merge(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 return error;
1779}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001780#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1781
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782/*
1783 * vma is the first one with address < vma->vm_start. Have to extend vma.
1784 */
Denys Vlasenkocb8f4882008-10-18 20:27:01 -07001785static int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001786 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787{
1788 int error;
1789
1790 /*
1791 * We must make sure the anon_vma is allocated
1792 * so that the anon_vma locking is not a noop.
1793 */
1794 if (unlikely(anon_vma_prepare(vma)))
1795 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001796
1797 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001798 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001799 if (error)
1800 return error;
1801
Rik van Rielbb4a3402010-08-09 17:18:37 -07001802 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803
1804 /*
1805 * vma->vm_start/vm_end cannot change under us because the caller
1806 * is required to hold the mmap_sem in read mode. We need the
1807 * anon_vma lock to serialize against concurrent expand_stacks.
1808 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809
1810 /* Somebody else might have raced and expanded it already */
1811 if (address < vma->vm_start) {
1812 unsigned long size, grow;
1813
1814 size = vma->vm_end - address;
1815 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1816
1817 error = acct_stack_growth(vma, size, grow);
1818 if (!error) {
1819 vma->vm_start = address;
1820 vma->vm_pgoff -= grow;
Eric B Munson3af9e852010-05-18 15:30:49 +01001821 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 }
1823 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001824 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001825 khugepaged_enter_vma_merge(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 return error;
1827}
1828
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001829int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1830{
1831 return expand_downwards(vma, address);
1832}
1833
1834#ifdef CONFIG_STACK_GROWSUP
1835int expand_stack(struct vm_area_struct *vma, unsigned long address)
1836{
1837 return expand_upwards(vma, address);
1838}
1839
1840struct vm_area_struct *
1841find_extend_vma(struct mm_struct *mm, unsigned long addr)
1842{
1843 struct vm_area_struct *vma, *prev;
1844
1845 addr &= PAGE_MASK;
1846 vma = find_vma_prev(mm, addr, &prev);
1847 if (vma && (vma->vm_start <= addr))
1848 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01001849 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001850 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001851 if (prev->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001852 mlock_vma_pages_range(prev, addr, prev->vm_end);
Rik van Rielba470de2008-10-18 20:26:50 -07001853 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001854 return prev;
1855}
1856#else
1857int expand_stack(struct vm_area_struct *vma, unsigned long address)
1858{
1859 return expand_downwards(vma, address);
1860}
1861
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862struct vm_area_struct *
1863find_extend_vma(struct mm_struct * mm, unsigned long addr)
1864{
1865 struct vm_area_struct * vma;
1866 unsigned long start;
1867
1868 addr &= PAGE_MASK;
1869 vma = find_vma(mm,addr);
1870 if (!vma)
1871 return NULL;
1872 if (vma->vm_start <= addr)
1873 return vma;
1874 if (!(vma->vm_flags & VM_GROWSDOWN))
1875 return NULL;
1876 start = vma->vm_start;
1877 if (expand_stack(vma, addr))
1878 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001879 if (vma->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001880 mlock_vma_pages_range(vma, addr, start);
Rik van Rielba470de2008-10-18 20:26:50 -07001881 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 return vma;
1883}
1884#endif
1885
Linus Torvalds1da177e2005-04-16 15:20:36 -07001886/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001887 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001889 *
1890 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001892static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001894 /* Update high watermark before we lower total_vm */
1895 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001897 long nrpages = vma_pages(vma);
1898
1899 mm->total_vm -= nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001900 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001901 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001902 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903 validate_mm(mm);
1904}
1905
1906/*
1907 * Get rid of page table information in the indicated region.
1908 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001909 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 */
1911static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001912 struct vm_area_struct *vma, struct vm_area_struct *prev,
1913 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001915 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916 struct mmu_gather *tlb;
1917 unsigned long nr_accounted = 0;
1918
1919 lru_add_drain();
1920 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001921 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001922 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07001924 free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001925 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 tlb_finish_mmu(tlb, start, end);
1927}
1928
1929/*
1930 * Create a list of vma's touched by the unmap, removing them from the mm's
1931 * vma list as we go..
1932 */
1933static void
1934detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1935 struct vm_area_struct *prev, unsigned long end)
1936{
1937 struct vm_area_struct **insertion_point;
1938 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001939 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940
1941 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001942 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 do {
1944 rb_erase(&vma->vm_rb, &mm->mm_rb);
1945 mm->map_count--;
1946 tail_vma = vma;
1947 vma = vma->vm_next;
1948 } while (vma && vma->vm_start < end);
1949 *insertion_point = vma;
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001950 if (vma)
1951 vma->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001953 if (mm->unmap_area == arch_unmap_area)
1954 addr = prev ? prev->vm_end : mm->mmap_base;
1955 else
1956 addr = vma ? vma->vm_start : mm->mmap_base;
1957 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 mm->mmap_cache = NULL; /* Kill the cache. */
1959}
1960
1961/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001962 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
1963 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001965static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966 unsigned long addr, int new_below)
1967{
1968 struct mempolicy *pol;
1969 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08001970 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001971
Andi Kleena5516432008-07-23 21:27:41 -07001972 if (is_vm_hugetlb_page(vma) && (addr &
1973 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 return -EINVAL;
1975
Christoph Lametere94b1762006-12-06 20:33:17 -08001976 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08001978 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979
1980 /* most fields are the same, copy all, and then fixup */
1981 *new = *vma;
1982
Rik van Riel5beb4932010-03-05 13:42:07 -08001983 INIT_LIST_HEAD(&new->anon_vma_chain);
1984
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 if (new_below)
1986 new->vm_end = addr;
1987 else {
1988 new->vm_start = addr;
1989 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1990 }
1991
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001992 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993 if (IS_ERR(pol)) {
Rik van Riel5beb4932010-03-05 13:42:07 -08001994 err = PTR_ERR(pol);
1995 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996 }
1997 vma_set_policy(new, pol);
1998
Rik van Riel5beb4932010-03-05 13:42:07 -08001999 if (anon_vma_clone(new, vma))
2000 goto out_free_mpol;
2001
Matt Helsley925d1c42008-04-29 01:01:36 -07002002 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002004 if (vma->vm_flags & VM_EXECUTABLE)
2005 added_exe_file_vma(mm);
2006 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007
2008 if (new->vm_ops && new->vm_ops->open)
2009 new->vm_ops->open(new);
2010
2011 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08002012 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 ((addr - new->vm_start) >> PAGE_SHIFT), new);
2014 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002015 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016
Rik van Riel5beb4932010-03-05 13:42:07 -08002017 /* Success. */
2018 if (!err)
2019 return 0;
2020
2021 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002022 if (new->vm_ops && new->vm_ops->close)
2023 new->vm_ops->close(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002024 if (new->vm_file) {
2025 if (vma->vm_flags & VM_EXECUTABLE)
2026 removed_exe_file_vma(mm);
2027 fput(new->vm_file);
2028 }
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002029 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002030 out_free_mpol:
2031 mpol_put(pol);
2032 out_free_vma:
2033 kmem_cache_free(vm_area_cachep, new);
2034 out_err:
2035 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036}
2037
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002038/*
2039 * Split a vma into two pieces at address 'addr', a new vma is allocated
2040 * either for the first part or the tail.
2041 */
2042int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2043 unsigned long addr, int new_below)
2044{
2045 if (mm->map_count >= sysctl_max_map_count)
2046 return -ENOMEM;
2047
2048 return __split_vma(mm, vma, addr, new_below);
2049}
2050
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051/* Munmap is split into 2 main parts -- this part which finds
2052 * what needs doing, and the areas themselves, which do the
2053 * work. This now handles partial unmappings.
2054 * Jeremy Fitzhardinge <jeremy@goop.org>
2055 */
2056int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2057{
2058 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002059 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060
2061 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2062 return -EINVAL;
2063
2064 if ((len = PAGE_ALIGN(len)) == 0)
2065 return -EINVAL;
2066
2067 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07002068 vma = find_vma_prev(mm, start, &prev);
2069 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07002071 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002072
2073 /* if it doesn't overlap, we have nothing.. */
2074 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002075 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076 return 0;
2077
2078 /*
2079 * If we need to split any vma, do it now to save pain later.
2080 *
2081 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2082 * unmapped vm_area_struct will remain in use: so lower split_vma
2083 * places tmp vma above, and higher split_vma places tmp vma below.
2084 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002085 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002086 int error;
2087
2088 /*
2089 * Make sure that map_count on return from munmap() will
2090 * not exceed its limit; but let map_count go just above
2091 * its limit temporarily, to help free resources as expected.
2092 */
2093 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2094 return -ENOMEM;
2095
2096 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002097 if (error)
2098 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002099 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 }
2101
2102 /* Does it split the last one? */
2103 last = find_vma(mm, end);
2104 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002105 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002106 if (error)
2107 return error;
2108 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002109 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110
2111 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002112 * unlock any mlock()ed ranges before detaching vmas
2113 */
2114 if (mm->locked_vm) {
2115 struct vm_area_struct *tmp = vma;
2116 while (tmp && tmp->vm_start < end) {
2117 if (tmp->vm_flags & VM_LOCKED) {
2118 mm->locked_vm -= vma_pages(tmp);
2119 munlock_vma_pages_all(tmp);
2120 }
2121 tmp = tmp->vm_next;
2122 }
2123 }
2124
2125 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002126 * Remove the vma's, and unmap the actual pages
2127 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002128 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2129 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130
2131 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002132 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133
2134 return 0;
2135}
2136
2137EXPORT_SYMBOL(do_munmap);
2138
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002139SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140{
2141 int ret;
2142 struct mm_struct *mm = current->mm;
2143
2144 profile_munmap(addr);
2145
2146 down_write(&mm->mmap_sem);
2147 ret = do_munmap(mm, addr, len);
2148 up_write(&mm->mmap_sem);
2149 return ret;
2150}
2151
2152static inline void verify_mm_writelocked(struct mm_struct *mm)
2153{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002154#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2156 WARN_ON(1);
2157 up_read(&mm->mmap_sem);
2158 }
2159#endif
2160}
2161
2162/*
2163 * this is really a simplified "do_mmap". it only handles
2164 * anonymous maps. eventually we may be able to do some
2165 * brk-specific accounting here.
2166 */
2167unsigned long do_brk(unsigned long addr, unsigned long len)
2168{
2169 struct mm_struct * mm = current->mm;
2170 struct vm_area_struct * vma, * prev;
2171 unsigned long flags;
2172 struct rb_node ** rb_link, * rb_parent;
2173 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002174 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002175
2176 len = PAGE_ALIGN(len);
2177 if (!len)
2178 return addr;
2179
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01002180 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05002181 if (error)
2182 return error;
2183
Kirill Korotaev3a459752006-09-07 14:17:04 +04002184 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2185
Al Viro2c6a10162009-12-03 19:40:46 -05002186 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2187 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002188 return error;
2189
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 /*
2191 * mlock MCL_FUTURE?
2192 */
2193 if (mm->def_flags & VM_LOCKED) {
2194 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002195 locked = len >> PAGE_SHIFT;
2196 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002197 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002198 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002199 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2200 return -EAGAIN;
2201 }
2202
2203 /*
2204 * mm->mmap_sem is required to protect against another thread
2205 * changing the mappings in case we sleep.
2206 */
2207 verify_mm_writelocked(mm);
2208
2209 /*
2210 * Clear old maps. this also does some error checking for us
2211 */
2212 munmap_back:
2213 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2214 if (vma && vma->vm_start < addr + len) {
2215 if (do_munmap(mm, addr, len))
2216 return -ENOMEM;
2217 goto munmap_back;
2218 }
2219
2220 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002221 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222 return -ENOMEM;
2223
2224 if (mm->map_count > sysctl_max_map_count)
2225 return -ENOMEM;
2226
2227 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2228 return -ENOMEM;
2229
Linus Torvalds1da177e2005-04-16 15:20:36 -07002230 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002231 vma = vma_merge(mm, prev, addr, addr + len, flags,
2232 NULL, NULL, pgoff, NULL);
2233 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 goto out;
2235
2236 /*
2237 * create a vma struct for an anonymous mapping
2238 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002239 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240 if (!vma) {
2241 vm_unacct_memory(len >> PAGE_SHIFT);
2242 return -ENOMEM;
2243 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244
Rik van Riel5beb4932010-03-05 13:42:07 -08002245 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246 vma->vm_mm = mm;
2247 vma->vm_start = addr;
2248 vma->vm_end = addr + len;
2249 vma->vm_pgoff = pgoff;
2250 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002251 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252 vma_link(mm, vma, prev, rb_link, rb_parent);
2253out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002254 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002255 mm->total_vm += len >> PAGE_SHIFT;
2256 if (flags & VM_LOCKED) {
Rik van Rielba470de2008-10-18 20:26:50 -07002257 if (!mlock_vma_pages_range(vma, addr, addr + len))
2258 mm->locked_vm += (len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259 }
2260 return addr;
2261}
2262
2263EXPORT_SYMBOL(do_brk);
2264
2265/* Release all mmaps. */
2266void exit_mmap(struct mm_struct *mm)
2267{
2268 struct mmu_gather *tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002269 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002271 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002273 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002274 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002275
Rik van Rielba470de2008-10-18 20:26:50 -07002276 if (mm->locked_vm) {
2277 vma = mm->mmap;
2278 while (vma) {
2279 if (vma->vm_flags & VM_LOCKED)
2280 munlock_vma_pages_all(vma);
2281 vma = vma->vm_next;
2282 }
2283 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002284
2285 arch_exit_mmap(mm);
2286
Rik van Rielba470de2008-10-18 20:26:50 -07002287 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002288 if (!vma) /* Can happen if dup_mmap() received an OOM */
2289 return;
2290
Linus Torvalds1da177e2005-04-16 15:20:36 -07002291 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002292 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002293 tlb = tlb_gather_mmu(mm, 1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002294 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002295 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002296 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297 vm_unacct_memory(nr_accounted);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002298
Jan Beulich42b77722008-07-23 21:27:10 -07002299 free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002300 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002303 * Walk the list again, actually closing and freeing it,
2304 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002305 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002306 while (vma)
2307 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002308
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002309 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310}
2311
2312/* Insert vm structure into process list sorted by address
2313 * and into the inode's i_mmap tree. If vm_file is non-NULL
2314 * then i_mmap_lock is taken here.
2315 */
2316int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2317{
2318 struct vm_area_struct * __vma, * prev;
2319 struct rb_node ** rb_link, * rb_parent;
2320
2321 /*
2322 * The vm_pgoff of a purely anonymous vma should be irrelevant
2323 * until its first write fault, when page's anon_vma and index
2324 * are set. But now set the vm_pgoff it will almost certainly
2325 * end up with (unless mremap moves it elsewhere before that
2326 * first wfault), so /proc/pid/maps tells a consistent story.
2327 *
2328 * By setting it to reflect the virtual start address of the
2329 * vma, merges and splits can happen in a seamless way, just
2330 * using the existing file pgoff checks and manipulations.
2331 * Similarly in do_mmap_pgoff and in do_brk.
2332 */
2333 if (!vma->vm_file) {
2334 BUG_ON(vma->anon_vma);
2335 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2336 }
2337 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2338 if (__vma && __vma->vm_start < vma->vm_end)
2339 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002340 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002341 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002342 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002343 vma_link(mm, vma, prev, rb_link, rb_parent);
2344 return 0;
2345}
2346
2347/*
2348 * Copy the vma structure to a new location in the same mm,
2349 * prior to moving page table entries, to effect an mremap move.
2350 */
2351struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2352 unsigned long addr, unsigned long len, pgoff_t pgoff)
2353{
2354 struct vm_area_struct *vma = *vmap;
2355 unsigned long vma_start = vma->vm_start;
2356 struct mm_struct *mm = vma->vm_mm;
2357 struct vm_area_struct *new_vma, *prev;
2358 struct rb_node **rb_link, *rb_parent;
2359 struct mempolicy *pol;
2360
2361 /*
2362 * If anonymous vma has not yet been faulted, update new pgoff
2363 * to match new location, to increase its chance of merging.
2364 */
2365 if (!vma->vm_file && !vma->anon_vma)
2366 pgoff = addr >> PAGE_SHIFT;
2367
2368 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2369 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2370 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2371 if (new_vma) {
2372 /*
2373 * Source vma may have been merged into new_vma
2374 */
2375 if (vma_start >= new_vma->vm_start &&
2376 vma_start < new_vma->vm_end)
2377 *vmap = new_vma;
2378 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002379 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 if (new_vma) {
2381 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002382 pol = mpol_dup(vma_policy(vma));
Rik van Riel5beb4932010-03-05 13:42:07 -08002383 if (IS_ERR(pol))
2384 goto out_free_vma;
2385 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2386 if (anon_vma_clone(new_vma, vma))
2387 goto out_free_mempol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388 vma_set_policy(new_vma, pol);
2389 new_vma->vm_start = addr;
2390 new_vma->vm_end = addr + len;
2391 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002392 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002394 if (vma->vm_flags & VM_EXECUTABLE)
2395 added_exe_file_vma(mm);
2396 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397 if (new_vma->vm_ops && new_vma->vm_ops->open)
2398 new_vma->vm_ops->open(new_vma);
2399 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2400 }
2401 }
2402 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002403
2404 out_free_mempol:
2405 mpol_put(pol);
2406 out_free_vma:
2407 kmem_cache_free(vm_area_cachep, new_vma);
2408 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002410
2411/*
2412 * Return true if the calling process may expand its vm space by the passed
2413 * number of pages
2414 */
2415int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2416{
2417 unsigned long cur = mm->total_vm; /* pages */
2418 unsigned long lim;
2419
Jiri Slaby59e99e52010-03-05 13:41:44 -08002420 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002421
2422 if (cur + npages > lim)
2423 return 0;
2424 return 1;
2425}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002426
2427
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002428static int special_mapping_fault(struct vm_area_struct *vma,
2429 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002430{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002431 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002432 struct page **pages;
2433
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002434 /*
2435 * special mappings have no vm_file, and in that case, the mm
2436 * uses vm_pgoff internally. So we have to subtract it from here.
2437 * We are allowed to do this because we are the mm; do not copy
2438 * this code into drivers!
2439 */
2440 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002441
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002442 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2443 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002444
2445 if (*pages) {
2446 struct page *page = *pages;
2447 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002448 vmf->page = page;
2449 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002450 }
2451
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002452 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002453}
2454
2455/*
2456 * Having a close hook prevents vma merging regardless of flags.
2457 */
2458static void special_mapping_close(struct vm_area_struct *vma)
2459{
2460}
2461
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002462static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002463 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002464 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002465};
2466
2467/*
2468 * Called with mm->mmap_sem held for writing.
2469 * Insert a new vma covering the given region, with the given flags.
2470 * Its pages are supplied by the given array of struct page *.
2471 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2472 * The region past the last page supplied will always produce SIGBUS.
2473 * The array pointer and the pages it points to are assumed to stay alive
2474 * for as long as this mapping might exist.
2475 */
2476int install_special_mapping(struct mm_struct *mm,
2477 unsigned long addr, unsigned long len,
2478 unsigned long vm_flags, struct page **pages)
2479{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002480 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002481 struct vm_area_struct *vma;
2482
2483 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2484 if (unlikely(vma == NULL))
2485 return -ENOMEM;
2486
Rik van Riel5beb4932010-03-05 13:42:07 -08002487 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002488 vma->vm_mm = mm;
2489 vma->vm_start = addr;
2490 vma->vm_end = addr + len;
2491
Nick Piggin2f987352008-02-02 03:08:53 +01002492 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002493 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002494
2495 vma->vm_ops = &special_mapping_vmops;
2496 vma->vm_private_data = pages;
2497
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002498 ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
2499 if (ret)
2500 goto out;
2501
2502 ret = insert_vm_struct(mm, vma);
2503 if (ret)
2504 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002505
2506 mm->total_vm += len >> PAGE_SHIFT;
2507
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002508 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002509
Roland McGrathfa5dc222007-02-08 14:20:41 -08002510 return 0;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002511
2512out:
2513 kmem_cache_free(vm_area_cachep, vma);
2514 return ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002515}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002516
2517static DEFINE_MUTEX(mm_all_locks_mutex);
2518
Peter Zijlstra454ed842008-08-11 09:30:25 +02002519static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002520{
Rik van Riel012f1802010-08-09 17:18:40 -07002521 if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002522 /*
2523 * The LSB of head.next can't change from under us
2524 * because we hold the mm_all_locks_mutex.
2525 */
Rik van Riel012f1802010-08-09 17:18:40 -07002526 spin_lock_nest_lock(&anon_vma->root->lock, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002527 /*
2528 * We can safely modify head.next after taking the
Rik van Riel012f1802010-08-09 17:18:40 -07002529 * anon_vma->root->lock. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002530 * the same anon_vma we won't take it again.
2531 *
2532 * No need of atomic instructions here, head.next
2533 * can't change from under us thanks to the
Rik van Riel012f1802010-08-09 17:18:40 -07002534 * anon_vma->root->lock.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002535 */
2536 if (__test_and_set_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002537 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002538 BUG();
2539 }
2540}
2541
Peter Zijlstra454ed842008-08-11 09:30:25 +02002542static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002543{
2544 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2545 /*
2546 * AS_MM_ALL_LOCKS can't change from under us because
2547 * we hold the mm_all_locks_mutex.
2548 *
2549 * Operations on ->flags have to be atomic because
2550 * even if AS_MM_ALL_LOCKS is stable thanks to the
2551 * mm_all_locks_mutex, there may be other cpus
2552 * changing other bitflags in parallel to us.
2553 */
2554 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2555 BUG();
Peter Zijlstra454ed842008-08-11 09:30:25 +02002556 spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002557 }
2558}
2559
2560/*
2561 * This operation locks against the VM for all pte/vma/mm related
2562 * operations that could ever happen on a certain mm. This includes
2563 * vmtruncate, try_to_unmap, and all page faults.
2564 *
2565 * The caller must take the mmap_sem in write mode before calling
2566 * mm_take_all_locks(). The caller isn't allowed to release the
2567 * mmap_sem until mm_drop_all_locks() returns.
2568 *
2569 * mmap_sem in write mode is required in order to block all operations
2570 * that could modify pagetables and free pages without need of
2571 * altering the vma layout (for example populate_range() with
2572 * nonlinear vmas). It's also needed in write mode to avoid new
2573 * anon_vmas to be associated with existing vmas.
2574 *
2575 * A single task can't take more than one mm_take_all_locks() in a row
2576 * or it would deadlock.
2577 *
2578 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2579 * mapping->flags avoid to take the same lock twice, if more than one
2580 * vma in this mm is backed by the same anon_vma or address_space.
2581 *
2582 * We can take all the locks in random order because the VM code
2583 * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never
2584 * takes more than one of them in a row. Secondly we're protected
2585 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2586 *
2587 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2588 * that may have to take thousand of locks.
2589 *
2590 * mm_take_all_locks() can fail if it's interrupted by signals.
2591 */
2592int mm_take_all_locks(struct mm_struct *mm)
2593{
2594 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002595 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002596 int ret = -EINTR;
2597
2598 BUG_ON(down_read_trylock(&mm->mmap_sem));
2599
2600 mutex_lock(&mm_all_locks_mutex);
2601
2602 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2603 if (signal_pending(current))
2604 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002605 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02002606 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002607 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002608
2609 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2610 if (signal_pending(current))
2611 goto out_unlock;
2612 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002613 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2614 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002615 }
2616
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002617 ret = 0;
2618
2619out_unlock:
2620 if (ret)
2621 mm_drop_all_locks(mm);
2622
2623 return ret;
2624}
2625
2626static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2627{
Rik van Riel012f1802010-08-09 17:18:40 -07002628 if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002629 /*
2630 * The LSB of head.next can't change to 0 from under
2631 * us because we hold the mm_all_locks_mutex.
2632 *
2633 * We must however clear the bitflag before unlocking
2634 * the vma so the users using the anon_vma->head will
2635 * never see our bitflag.
2636 *
2637 * No need of atomic instructions here, head.next
2638 * can't change from under us until we release the
Rik van Riel012f1802010-08-09 17:18:40 -07002639 * anon_vma->root->lock.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002640 */
2641 if (!__test_and_clear_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002642 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002643 BUG();
Rik van Rielcba48b92010-08-09 17:18:38 -07002644 anon_vma_unlock(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002645 }
2646}
2647
2648static void vm_unlock_mapping(struct address_space *mapping)
2649{
2650 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2651 /*
2652 * AS_MM_ALL_LOCKS can't change to 0 from under us
2653 * because we hold the mm_all_locks_mutex.
2654 */
2655 spin_unlock(&mapping->i_mmap_lock);
2656 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2657 &mapping->flags))
2658 BUG();
2659 }
2660}
2661
2662/*
2663 * The mmap_sem cannot be released by the caller until
2664 * mm_drop_all_locks() returns.
2665 */
2666void mm_drop_all_locks(struct mm_struct *mm)
2667{
2668 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002669 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002670
2671 BUG_ON(down_read_trylock(&mm->mmap_sem));
2672 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2673
2674 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2675 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002676 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2677 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002678 if (vma->vm_file && vma->vm_file->f_mapping)
2679 vm_unlock_mapping(vma->vm_file->f_mapping);
2680 }
2681
2682 mutex_unlock(&mm_all_locks_mutex);
2683}
David Howells8feae132009-01-08 12:04:47 +00002684
2685/*
2686 * initialise the VMA slab
2687 */
2688void __init mmap_init(void)
2689{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07002690 int ret;
2691
2692 ret = percpu_counter_init(&vm_committed_as, 0);
2693 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00002694}