blob: b179abb1474ae41bff47060b5241045d3b1b12ad [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33#include <asm/uaccess.h>
34#include <asm/cacheflush.h>
35#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020036#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Jan Beulich42b77722008-07-23 21:27:10 -070038#include "internal.h"
39
Kirill Korotaev3a459752006-09-07 14:17:04 +040040#ifndef arch_mmap_check
41#define arch_mmap_check(addr, len, flags) (0)
42#endif
43
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080044#ifndef arch_rebalance_pgtables
45#define arch_rebalance_pgtables(addr, len) (addr)
46#endif
47
Hugh Dickinse0da3822005-04-19 13:29:15 -070048static void unmap_region(struct mm_struct *mm,
49 struct vm_area_struct *vma, struct vm_area_struct *prev,
50 unsigned long start, unsigned long end);
51
Linus Torvalds1da177e2005-04-16 15:20:36 -070052/*
53 * WARNING: the debugging will use recursive algorithms so never enable this
54 * unless you know what you are doing.
55 */
56#undef DEBUG_MM_RB
57
58/* description of effects of mapping type and prot in current implementation.
59 * this is due to the limited x86 page protection hardware. The expected
60 * behavior is in parens:
61 *
62 * map_type prot
63 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
64 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
65 * w: (no) no w: (no) no w: (yes) yes w: (no) no
66 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
67 *
68 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
69 * w: (no) no w: (no) no w: (copy) copy w: (no) no
70 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
71 *
72 */
73pgprot_t protection_map[16] = {
74 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
75 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
76};
77
Hugh Dickins804af2c2006-07-26 21:39:49 +010078pgprot_t vm_get_page_prot(unsigned long vm_flags)
79{
Dave Kleikampb845f312008-07-08 00:28:51 +100080 return __pgprot(pgprot_val(protection_map[vm_flags &
81 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
82 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010083}
84EXPORT_SYMBOL(vm_get_page_prot);
85
Linus Torvalds1da177e2005-04-16 15:20:36 -070086int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
87int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070088int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -070089struct percpu_counter vm_committed_as;
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91/*
92 * Check that a process has enough memory to allocate a new virtual
93 * mapping. 0 means there is enough memory for the allocation to
94 * succeed and -ENOMEM implies there is not.
95 *
96 * We currently support three overcommit policies, which are set via the
97 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
98 *
99 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
100 * Additional code 2002 Jul 20 by Robert Love.
101 *
102 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
103 *
104 * Note this is a helper function intended to be used by LSMs which
105 * wish to use this logic.
106 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700107int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
109 unsigned long free, allowed;
110
111 vm_acct_memory(pages);
112
113 /*
114 * Sometimes we want to use more memory than we have
115 */
116 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
117 return 0;
118
119 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
120 unsigned long n;
121
Christoph Lameter347ce432006-06-30 01:55:35 -0700122 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 free += nr_swap_pages;
124
125 /*
126 * Any slabs which are created with the
127 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
128 * which are reclaimable, under pressure. The dentry
129 * cache and most inode caches should fall into this
130 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700131 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
133 /*
134 * Leave the last 3% for root
135 */
136 if (!cap_sys_admin)
137 free -= free / 32;
138
139 if (free > pages)
140 return 0;
141
142 /*
143 * nr_free_pages() is very expensive on large systems,
144 * only call if we're about to fail.
145 */
146 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700147
148 /*
149 * Leave reserved pages. The pages are not for anonymous pages.
150 */
151 if (n <= totalreserve_pages)
152 goto error;
153 else
154 n -= totalreserve_pages;
155
156 /*
157 * Leave the last 3% for root
158 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 if (!cap_sys_admin)
160 n -= n / 32;
161 free += n;
162
163 if (free > pages)
164 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700165
166 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 }
168
169 allowed = (totalram_pages - hugetlb_total_pages())
170 * sysctl_overcommit_ratio / 100;
171 /*
172 * Leave the last 3% for root
173 */
174 if (!cap_sys_admin)
175 allowed -= allowed / 32;
176 allowed += total_swap_pages;
177
178 /* Don't let a single process grow too big:
179 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -0700180 if (mm)
181 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700183 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700185error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 vm_unacct_memory(pages);
187
188 return -ENOMEM;
189}
190
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191/*
192 * Requires inode->i_mapping->i_mmap_lock
193 */
194static void __remove_shared_vm_struct(struct vm_area_struct *vma,
195 struct file *file, struct address_space *mapping)
196{
197 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800198 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 if (vma->vm_flags & VM_SHARED)
200 mapping->i_mmap_writable--;
201
202 flush_dcache_mmap_lock(mapping);
203 if (unlikely(vma->vm_flags & VM_NONLINEAR))
204 list_del_init(&vma->shared.vm_set.list);
205 else
206 vma_prio_tree_remove(vma, &mapping->i_mmap);
207 flush_dcache_mmap_unlock(mapping);
208}
209
210/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700211 * Unlink a file-based vm structure from its prio_tree, to hide
212 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700214void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215{
216 struct file *file = vma->vm_file;
217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 if (file) {
219 struct address_space *mapping = file->f_mapping;
220 spin_lock(&mapping->i_mmap_lock);
221 __remove_shared_vm_struct(vma, file, mapping);
222 spin_unlock(&mapping->i_mmap_lock);
223 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700224}
225
226/*
227 * Close a vm structure and free it, returning the next.
228 */
229static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
230{
231 struct vm_area_struct *next = vma->vm_next;
232
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700233 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 if (vma->vm_ops && vma->vm_ops->close)
235 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700236 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700237 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700238 if (vma->vm_flags & VM_EXECUTABLE)
239 removed_exe_file_vma(vma->vm_mm);
240 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700241 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700243 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100246SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247{
248 unsigned long rlim, retval;
249 unsigned long newbrk, oldbrk;
250 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700251 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 down_write(&mm->mmap_sem);
254
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700255#ifdef CONFIG_COMPAT_BRK
256 min_brk = mm->end_code;
257#else
258 min_brk = mm->start_brk;
259#endif
260 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700262
263 /*
264 * Check against rlimit here. If this check is done later after the test
265 * of oldbrk with newbrk then it can escape the test and let the data
266 * segment grow beyond its set limit the in case where the limit is
267 * not page aligned -Ram Gupta
268 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800269 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100270 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
271 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700272 goto out;
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 newbrk = PAGE_ALIGN(brk);
275 oldbrk = PAGE_ALIGN(mm->brk);
276 if (oldbrk == newbrk)
277 goto set_brk;
278
279 /* Always allow shrinking brk. */
280 if (brk <= mm->brk) {
281 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
282 goto set_brk;
283 goto out;
284 }
285
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 /* Check against existing mmap mappings. */
287 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
288 goto out;
289
290 /* Ok, looks good - let it rip. */
291 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
292 goto out;
293set_brk:
294 mm->brk = brk;
295out:
296 retval = mm->brk;
297 up_write(&mm->mmap_sem);
298 return retval;
299}
300
301#ifdef DEBUG_MM_RB
302static int browse_rb(struct rb_root *root)
303{
304 int i = 0, j;
305 struct rb_node *nd, *pn = NULL;
306 unsigned long prev = 0, pend = 0;
307
308 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
309 struct vm_area_struct *vma;
310 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
311 if (vma->vm_start < prev)
312 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
313 if (vma->vm_start < pend)
314 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
315 if (vma->vm_start > vma->vm_end)
316 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
317 i++;
318 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800319 prev = vma->vm_start;
320 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 }
322 j = 0;
323 for (nd = pn; nd; nd = rb_prev(nd)) {
324 j++;
325 }
326 if (i != j)
327 printk("backwards %d, forwards %d\n", j, i), i = 0;
328 return i;
329}
330
331void validate_mm(struct mm_struct *mm)
332{
333 int bug = 0;
334 int i = 0;
335 struct vm_area_struct *tmp = mm->mmap;
336 while (tmp) {
337 tmp = tmp->vm_next;
338 i++;
339 }
340 if (i != mm->map_count)
341 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
342 i = browse_rb(&mm->mm_rb);
343 if (i != mm->map_count)
344 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200345 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347#else
348#define validate_mm(mm) do { } while (0)
349#endif
350
351static struct vm_area_struct *
352find_vma_prepare(struct mm_struct *mm, unsigned long addr,
353 struct vm_area_struct **pprev, struct rb_node ***rb_link,
354 struct rb_node ** rb_parent)
355{
356 struct vm_area_struct * vma;
357 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
358
359 __rb_link = &mm->mm_rb.rb_node;
360 rb_prev = __rb_parent = NULL;
361 vma = NULL;
362
363 while (*__rb_link) {
364 struct vm_area_struct *vma_tmp;
365
366 __rb_parent = *__rb_link;
367 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
368
369 if (vma_tmp->vm_end > addr) {
370 vma = vma_tmp;
371 if (vma_tmp->vm_start <= addr)
Benny Halevydfe195f2008-08-05 13:01:41 -0700372 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 __rb_link = &__rb_parent->rb_left;
374 } else {
375 rb_prev = __rb_parent;
376 __rb_link = &__rb_parent->rb_right;
377 }
378 }
379
380 *pprev = NULL;
381 if (rb_prev)
382 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
383 *rb_link = __rb_link;
384 *rb_parent = __rb_parent;
385 return vma;
386}
387
388static inline void
389__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
390 struct vm_area_struct *prev, struct rb_node *rb_parent)
391{
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700392 struct vm_area_struct *next;
393
394 vma->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 if (prev) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700396 next = prev->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 prev->vm_next = vma;
398 } else {
399 mm->mmap = vma;
400 if (rb_parent)
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700401 next = rb_entry(rb_parent,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 struct vm_area_struct, vm_rb);
403 else
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700404 next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 }
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700406 vma->vm_next = next;
407 if (next)
408 next->vm_prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409}
410
411void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
412 struct rb_node **rb_link, struct rb_node *rb_parent)
413{
414 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
415 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
416}
417
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700418static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419{
ZhenwenXu48aae422009-01-06 14:40:21 -0800420 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
422 file = vma->vm_file;
423 if (file) {
424 struct address_space *mapping = file->f_mapping;
425
426 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800427 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 if (vma->vm_flags & VM_SHARED)
429 mapping->i_mmap_writable++;
430
431 flush_dcache_mmap_lock(mapping);
432 if (unlikely(vma->vm_flags & VM_NONLINEAR))
433 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
434 else
435 vma_prio_tree_insert(vma, &mapping->i_mmap);
436 flush_dcache_mmap_unlock(mapping);
437 }
438}
439
440static void
441__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
442 struct vm_area_struct *prev, struct rb_node **rb_link,
443 struct rb_node *rb_parent)
444{
445 __vma_link_list(mm, vma, prev, rb_parent);
446 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447}
448
449static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
450 struct vm_area_struct *prev, struct rb_node **rb_link,
451 struct rb_node *rb_parent)
452{
453 struct address_space *mapping = NULL;
454
455 if (vma->vm_file)
456 mapping = vma->vm_file->f_mapping;
457
458 if (mapping) {
459 spin_lock(&mapping->i_mmap_lock);
460 vma->vm_truncate_count = mapping->truncate_count;
461 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
463 __vma_link(mm, vma, prev, rb_link, rb_parent);
464 __vma_link_file(vma);
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 if (mapping)
467 spin_unlock(&mapping->i_mmap_lock);
468
469 mm->map_count++;
470 validate_mm(mm);
471}
472
473/*
474 * Helper for vma_adjust in the split_vma insert case:
475 * insert vm structure into list and rbtree and anon_vma,
476 * but it has already been inserted into prio_tree earlier.
477 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800478static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479{
ZhenwenXu48aae422009-01-06 14:40:21 -0800480 struct vm_area_struct *__vma, *prev;
481 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482
483 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200484 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 __vma_link(mm, vma, prev, rb_link, rb_parent);
486 mm->map_count++;
487}
488
489static inline void
490__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
491 struct vm_area_struct *prev)
492{
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700493 struct vm_area_struct *next = vma->vm_next;
494
495 prev->vm_next = next;
496 if (next)
497 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 rb_erase(&vma->vm_rb, &mm->mm_rb);
499 if (mm->mmap_cache == vma)
500 mm->mmap_cache = prev;
501}
502
503/*
504 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
505 * is already present in an i_mmap tree without adjusting the tree.
506 * The following helper function should be used when such adjustments
507 * are necessary. The "insert" vma (if any) is to be inserted
508 * before we drop the necessary locks.
509 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800510int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
512{
513 struct mm_struct *mm = vma->vm_mm;
514 struct vm_area_struct *next = vma->vm_next;
515 struct vm_area_struct *importer = NULL;
516 struct address_space *mapping = NULL;
517 struct prio_tree_root *root = NULL;
Rik van Riel012f1802010-08-09 17:18:40 -0700518 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 struct file *file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 long adjust_next = 0;
521 int remove_next = 0;
522
523 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700524 struct vm_area_struct *exporter = NULL;
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 if (end >= next->vm_end) {
527 /*
528 * vma expands, overlapping all the next, and
529 * perhaps the one after too (mprotect case 6).
530 */
531again: remove_next = 1 + (end > next->vm_end);
532 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700533 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 importer = vma;
535 } else if (end > next->vm_start) {
536 /*
537 * vma expands, overlapping part of the next:
538 * mprotect case 5 shifting the boundary up.
539 */
540 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700541 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 importer = vma;
543 } else if (end < vma->vm_end) {
544 /*
545 * vma shrinks, and !insert tells it's not
546 * split_vma inserting another: so it must be
547 * mprotect case 4 shifting the boundary down.
548 */
549 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700550 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 importer = next;
552 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
Rik van Riel5beb4932010-03-05 13:42:07 -0800554 /*
555 * Easily overlooked: when mprotect shifts the boundary,
556 * make sure the expanding vma has anon_vma set if the
557 * shrinking vma had, to cover any anon pages imported.
558 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700559 if (exporter && exporter->anon_vma && !importer->anon_vma) {
560 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800561 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700562 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800563 }
564 }
565
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 if (file) {
567 mapping = file->f_mapping;
568 if (!(vma->vm_flags & VM_NONLINEAR))
569 root = &mapping->i_mmap;
570 spin_lock(&mapping->i_mmap_lock);
571 if (importer &&
572 vma->vm_truncate_count != next->vm_truncate_count) {
573 /*
574 * unmap_mapping_range might be in progress:
575 * ensure that the expanding vma is rescanned.
576 */
577 importer->vm_truncate_count = 0;
578 }
579 if (insert) {
580 insert->vm_truncate_count = vma->vm_truncate_count;
581 /*
582 * Put into prio_tree now, so instantiated pages
583 * are visible to arm/parisc __flush_dcache_page
584 * throughout; but we cannot insert into address
585 * space until vma start or end is updated.
586 */
587 __vma_link_file(insert);
588 }
589 }
590
Rik van Riel012f1802010-08-09 17:18:40 -0700591 /*
592 * When changing only vma->vm_end, we don't really need anon_vma
593 * lock. This is a fairly rare case by itself, but the anon_vma
594 * lock may be shared between many sibling processes. Skipping
595 * the lock for brk adjustments makes a difference sometimes.
596 */
597 if (vma->anon_vma && (insert || importer || start != vma->vm_start)) {
598 anon_vma = vma->anon_vma;
599 anon_vma_lock(anon_vma);
600 }
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (root) {
603 flush_dcache_mmap_lock(mapping);
604 vma_prio_tree_remove(vma, root);
605 if (adjust_next)
606 vma_prio_tree_remove(next, root);
607 }
608
609 vma->vm_start = start;
610 vma->vm_end = end;
611 vma->vm_pgoff = pgoff;
612 if (adjust_next) {
613 next->vm_start += adjust_next << PAGE_SHIFT;
614 next->vm_pgoff += adjust_next;
615 }
616
617 if (root) {
618 if (adjust_next)
619 vma_prio_tree_insert(next, root);
620 vma_prio_tree_insert(vma, root);
621 flush_dcache_mmap_unlock(mapping);
622 }
623
624 if (remove_next) {
625 /*
626 * vma_merge has merged next into vma, and needs
627 * us to remove next before dropping the locks.
628 */
629 __vma_unlink(mm, next, vma);
630 if (file)
631 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 } else if (insert) {
633 /*
634 * split_vma has split insert from vma, and needs
635 * us to insert it before dropping the locks
636 * (it may either follow vma or precede it).
637 */
638 __insert_vm_struct(mm, insert);
639 }
640
Rik van Riel012f1802010-08-09 17:18:40 -0700641 if (anon_vma)
642 anon_vma_unlock(anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 if (mapping)
644 spin_unlock(&mapping->i_mmap_lock);
645
646 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700647 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700649 if (next->vm_flags & VM_EXECUTABLE)
650 removed_exe_file_vma(mm);
651 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800652 if (next->anon_vma)
653 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700655 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 kmem_cache_free(vm_area_cachep, next);
657 /*
658 * In mprotect's case 6 (see comments on vma_merge),
659 * we must remove another next too. It would clutter
660 * up the code too much to do both in one go.
661 */
662 if (remove_next == 2) {
663 next = vma->vm_next;
664 goto again;
665 }
666 }
667
668 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800669
670 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671}
672
673/*
674 * If the vma has a ->close operation then the driver probably needs to release
675 * per-vma resources, so we don't attempt to merge those.
676 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677static inline int is_mergeable_vma(struct vm_area_struct *vma,
678 struct file *file, unsigned long vm_flags)
679{
Hugh Dickins8314c4f2009-09-21 17:02:25 -0700680 /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
681 if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 return 0;
683 if (vma->vm_file != file)
684 return 0;
685 if (vma->vm_ops && vma->vm_ops->close)
686 return 0;
687 return 1;
688}
689
690static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
691 struct anon_vma *anon_vma2)
692{
693 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
694}
695
696/*
697 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
698 * in front of (at a lower virtual address and file offset than) the vma.
699 *
700 * We cannot merge two vmas if they have differently assigned (non-NULL)
701 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
702 *
703 * We don't check here for the merged mmap wrapping around the end of pagecache
704 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
705 * wrap, nor mmaps which cover the final page at index -1UL.
706 */
707static int
708can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
709 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
710{
711 if (is_mergeable_vma(vma, file, vm_flags) &&
712 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
713 if (vma->vm_pgoff == vm_pgoff)
714 return 1;
715 }
716 return 0;
717}
718
719/*
720 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
721 * beyond (at a higher virtual address and file offset than) the vma.
722 *
723 * We cannot merge two vmas if they have differently assigned (non-NULL)
724 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
725 */
726static int
727can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
728 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
729{
730 if (is_mergeable_vma(vma, file, vm_flags) &&
731 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
732 pgoff_t vm_pglen;
733 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
734 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
735 return 1;
736 }
737 return 0;
738}
739
740/*
741 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
742 * whether that can be merged with its predecessor or its successor.
743 * Or both (it neatly fills a hole).
744 *
745 * In most cases - when called for mmap, brk or mremap - [addr,end) is
746 * certain not to be mapped by the time vma_merge is called; but when
747 * called for mprotect, it is certain to be already mapped (either at
748 * an offset within prev, or at the start of next), and the flags of
749 * this area are about to be changed to vm_flags - and the no-change
750 * case has already been eliminated.
751 *
752 * The following mprotect cases have to be considered, where AAAA is
753 * the area passed down from mprotect_fixup, never extending beyond one
754 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
755 *
756 * AAAA AAAA AAAA AAAA
757 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
758 * cannot merge might become might become might become
759 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
760 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
761 * mremap move: PPPPNNNNNNNN 8
762 * AAAA
763 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
764 * might become case 1 below case 2 below case 3 below
765 *
766 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
767 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
768 */
769struct vm_area_struct *vma_merge(struct mm_struct *mm,
770 struct vm_area_struct *prev, unsigned long addr,
771 unsigned long end, unsigned long vm_flags,
772 struct anon_vma *anon_vma, struct file *file,
773 pgoff_t pgoff, struct mempolicy *policy)
774{
775 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
776 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800777 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778
779 /*
780 * We later require that vma->vm_flags == vm_flags,
781 * so this tests vma->vm_flags & VM_SPECIAL, too.
782 */
783 if (vm_flags & VM_SPECIAL)
784 return NULL;
785
786 if (prev)
787 next = prev->vm_next;
788 else
789 next = mm->mmap;
790 area = next;
791 if (next && next->vm_end == end) /* cases 6, 7, 8 */
792 next = next->vm_next;
793
794 /*
795 * Can it merge with the predecessor?
796 */
797 if (prev && prev->vm_end == addr &&
798 mpol_equal(vma_policy(prev), policy) &&
799 can_vma_merge_after(prev, vm_flags,
800 anon_vma, file, pgoff)) {
801 /*
802 * OK, it can. Can we now merge in the successor as well?
803 */
804 if (next && end == next->vm_start &&
805 mpol_equal(policy, vma_policy(next)) &&
806 can_vma_merge_before(next, vm_flags,
807 anon_vma, file, pgoff+pglen) &&
808 is_mergeable_anon_vma(prev->anon_vma,
809 next->anon_vma)) {
810 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800811 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 next->vm_end, prev->vm_pgoff, NULL);
813 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800814 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800816 if (err)
817 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 return prev;
819 }
820
821 /*
822 * Can this new request be merged in front of next?
823 */
824 if (next && end == next->vm_start &&
825 mpol_equal(policy, vma_policy(next)) &&
826 can_vma_merge_before(next, vm_flags,
827 anon_vma, file, pgoff+pglen)) {
828 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800829 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 addr, prev->vm_pgoff, NULL);
831 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800832 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800834 if (err)
835 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 return area;
837 }
838
839 return NULL;
840}
841
842/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700843 * Rough compatbility check to quickly see if it's even worth looking
844 * at sharing an anon_vma.
845 *
846 * They need to have the same vm_file, and the flags can only differ
847 * in things that mprotect may change.
848 *
849 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
850 * we can merge the two vma's. For example, we refuse to merge a vma if
851 * there is a vm_ops->close() function, because that indicates that the
852 * driver is doing some kind of reference counting. But that doesn't
853 * really matter for the anon_vma sharing case.
854 */
855static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
856{
857 return a->vm_end == b->vm_start &&
858 mpol_equal(vma_policy(a), vma_policy(b)) &&
859 a->vm_file == b->vm_file &&
860 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
861 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
862}
863
864/*
865 * Do some basic sanity checking to see if we can re-use the anon_vma
866 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
867 * the same as 'old', the other will be the new one that is trying
868 * to share the anon_vma.
869 *
870 * NOTE! This runs with mm_sem held for reading, so it is possible that
871 * the anon_vma of 'old' is concurrently in the process of being set up
872 * by another page fault trying to merge _that_. But that's ok: if it
873 * is being set up, that automatically means that it will be a singleton
874 * acceptable for merging, so we can do all of this optimistically. But
875 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
876 *
877 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
878 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
879 * is to return an anon_vma that is "complex" due to having gone through
880 * a fork).
881 *
882 * We also make sure that the two vma's are compatible (adjacent,
883 * and with the same memory policies). That's all stable, even with just
884 * a read lock on the mm_sem.
885 */
886static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
887{
888 if (anon_vma_compatible(a, b)) {
889 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
890
891 if (anon_vma && list_is_singular(&old->anon_vma_chain))
892 return anon_vma;
893 }
894 return NULL;
895}
896
897/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
899 * neighbouring vmas for a suitable anon_vma, before it goes off
900 * to allocate a new anon_vma. It checks because a repetitive
901 * sequence of mprotects and faults may otherwise lead to distinct
902 * anon_vmas being allocated, preventing vma merge in subsequent
903 * mprotect.
904 */
905struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
906{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700907 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909
910 near = vma->vm_next;
911 if (!near)
912 goto try_prev;
913
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700914 anon_vma = reusable_anon_vma(near, vma, near);
915 if (anon_vma)
916 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917try_prev:
918 /*
919 * It is potentially slow to have to call find_vma_prev here.
920 * But it's only on the first write fault on the vma, not
921 * every time, and we could devise a way to avoid it later
922 * (e.g. stash info in next's anon_vma_node when assigning
923 * an anon_vma, or when trying vma_merge). Another time.
924 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200925 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 if (!near)
927 goto none;
928
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700929 anon_vma = reusable_anon_vma(near, near, vma);
930 if (anon_vma)
931 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932none:
933 /*
934 * There's no absolute need to look only at touching neighbours:
935 * we could search further afield for "compatible" anon_vmas.
936 * But it would probably just be a waste of time searching,
937 * or lead to too many vmas hanging off the same anon_vma.
938 * We're trying to allow mprotect remerging later on,
939 * not trying to minimize memory used for anon_vmas.
940 */
941 return NULL;
942}
943
944#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700945void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 struct file *file, long pages)
947{
948 const unsigned long stack_flags
949 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
950
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 if (file) {
952 mm->shared_vm += pages;
953 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
954 mm->exec_vm += pages;
955 } else if (flags & stack_flags)
956 mm->stack_vm += pages;
957 if (flags & (VM_RESERVED|VM_IO))
958 mm->reserved_vm += pages;
959}
960#endif /* CONFIG_PROC_FS */
961
962/*
Jianjun Kong27f5de72009-09-17 19:26:26 -0700963 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 */
965
ZhenwenXu48aae422009-01-06 14:40:21 -0800966unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 unsigned long len, unsigned long prot,
968 unsigned long flags, unsigned long pgoff)
969{
970 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 struct inode *inode;
972 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 int error;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700974 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 /*
977 * Does the application expect PROT_READ to imply PROT_EXEC?
978 *
979 * (the exception is when the underlying filesystem is noexec
980 * mounted, in which case we dont add PROT_EXEC.)
981 */
982 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800983 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 prot |= PROT_EXEC;
985
986 if (!len)
987 return -EINVAL;
988
Eric Paris7cd94142007-11-26 18:47:40 -0500989 if (!(flags & MAP_FIXED))
990 addr = round_hint_to_min(addr);
991
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 /* Careful about overflows.. */
993 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -0500994 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 return -ENOMEM;
996
997 /* offset overflow? */
998 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
999 return -EOVERFLOW;
1000
1001 /* Too many mappings? */
1002 if (mm->map_count > sysctl_max_map_count)
1003 return -ENOMEM;
1004
1005 /* Obtain the address to map to. we verify (or select) it and ensure
1006 * that it represents a valid section of the address space.
1007 */
1008 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1009 if (addr & ~PAGE_MASK)
1010 return addr;
1011
1012 /* Do simple checking here so the lower-level routines won't have
1013 * to. we assume access permissions have been handled by the open
1014 * of the memory object, so we don't do any here.
1015 */
1016 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1017 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1018
Huang Shijiecdf7b342009-09-21 17:03:36 -07001019 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 if (!can_do_mlock())
1021 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001022
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 /* mlock MCL_FUTURE? */
1024 if (vm_flags & VM_LOCKED) {
1025 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001026 locked = len >> PAGE_SHIFT;
1027 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001028 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001029 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1031 return -EAGAIN;
1032 }
1033
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001034 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
1036 if (file) {
1037 switch (flags & MAP_TYPE) {
1038 case MAP_SHARED:
1039 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1040 return -EACCES;
1041
1042 /*
1043 * Make sure we don't allow writing to an append-only
1044 * file..
1045 */
1046 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1047 return -EACCES;
1048
1049 /*
1050 * Make sure there are no mandatory locks on the file.
1051 */
1052 if (locks_verify_locked(inode))
1053 return -EAGAIN;
1054
1055 vm_flags |= VM_SHARED | VM_MAYSHARE;
1056 if (!(file->f_mode & FMODE_WRITE))
1057 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1058
1059 /* fall through */
1060 case MAP_PRIVATE:
1061 if (!(file->f_mode & FMODE_READ))
1062 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001063 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001064 if (vm_flags & VM_EXEC)
1065 return -EPERM;
1066 vm_flags &= ~VM_MAYEXEC;
1067 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001068
1069 if (!file->f_op || !file->f_op->mmap)
1070 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 break;
1072
1073 default:
1074 return -EINVAL;
1075 }
1076 } else {
1077 switch (flags & MAP_TYPE) {
1078 case MAP_SHARED:
Tejun Heoce363942008-09-03 16:09:47 +02001079 /*
1080 * Ignore pgoff.
1081 */
1082 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 vm_flags |= VM_SHARED | VM_MAYSHARE;
1084 break;
1085 case MAP_PRIVATE:
1086 /*
1087 * Set pgoff according to addr for anon_vma.
1088 */
1089 pgoff = addr >> PAGE_SHIFT;
1090 break;
1091 default:
1092 return -EINVAL;
1093 }
1094 }
1095
Eric Parised032182007-06-28 15:55:21 -04001096 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 if (error)
1098 return error;
Eric Parised032182007-06-28 15:55:21 -04001099
Mel Gorman5a6fe122009-02-10 14:02:27 +00001100 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001101}
1102EXPORT_SYMBOL(do_mmap_pgoff);
1103
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001104SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1105 unsigned long, prot, unsigned long, flags,
1106 unsigned long, fd, unsigned long, pgoff)
1107{
1108 struct file *file = NULL;
1109 unsigned long retval = -EBADF;
1110
1111 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001112 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001113 if (unlikely(flags & MAP_HUGETLB))
1114 return -EINVAL;
1115 file = fget(fd);
1116 if (!file)
1117 goto out;
1118 } else if (flags & MAP_HUGETLB) {
1119 struct user_struct *user = NULL;
1120 /*
1121 * VM_NORESERVE is used because the reservations will be
1122 * taken when vm_ops->mmap() is called
1123 * A dummy user value is used because we are not locking
1124 * memory so no accounting is necessary
1125 */
1126 len = ALIGN(len, huge_page_size(&default_hstate));
1127 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
1128 &user, HUGETLB_ANONHUGE_INODE);
1129 if (IS_ERR(file))
1130 return PTR_ERR(file);
1131 }
1132
1133 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1134
1135 down_write(&current->mm->mmap_sem);
1136 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1137 up_write(&current->mm->mmap_sem);
1138
1139 if (file)
1140 fput(file);
1141out:
1142 return retval;
1143}
1144
Christoph Hellwiga4679372010-03-10 15:21:15 -08001145#ifdef __ARCH_WANT_SYS_OLD_MMAP
1146struct mmap_arg_struct {
1147 unsigned long addr;
1148 unsigned long len;
1149 unsigned long prot;
1150 unsigned long flags;
1151 unsigned long fd;
1152 unsigned long offset;
1153};
1154
1155SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1156{
1157 struct mmap_arg_struct a;
1158
1159 if (copy_from_user(&a, arg, sizeof(a)))
1160 return -EFAULT;
1161 if (a.offset & ~PAGE_MASK)
1162 return -EINVAL;
1163
1164 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1165 a.offset >> PAGE_SHIFT);
1166}
1167#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1168
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001169/*
1170 * Some shared mappigns will want the pages marked read-only
1171 * to track write events. If so, we'll downgrade vm_page_prot
1172 * to the private version (using protection_map[] without the
1173 * VM_SHARED bit).
1174 */
1175int vma_wants_writenotify(struct vm_area_struct *vma)
1176{
1177 unsigned int vm_flags = vma->vm_flags;
1178
1179 /* If it was private or non-writable, the write bit is already clear */
1180 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1181 return 0;
1182
1183 /* The backer wishes to know when pages are first written to? */
1184 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1185 return 1;
1186
1187 /* The open routine did something to the protections already? */
1188 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001189 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001190 return 0;
1191
1192 /* Specialty mapping? */
1193 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1194 return 0;
1195
1196 /* Can the mapping track the dirty pages? */
1197 return vma->vm_file && vma->vm_file->f_mapping &&
1198 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1199}
1200
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001201/*
1202 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001203 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001204 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001205static inline int accountable_mapping(struct file *file, unsigned int vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001206{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001207 /*
1208 * hugetlb has its own accounting separate from the core VM
1209 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1210 */
1211 if (file && is_file_hugepages(file))
1212 return 0;
1213
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001214 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1215}
1216
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001217unsigned long mmap_region(struct file *file, unsigned long addr,
1218 unsigned long len, unsigned long flags,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001219 unsigned int vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001220{
1221 struct mm_struct *mm = current->mm;
1222 struct vm_area_struct *vma, *prev;
1223 int correct_wcount = 0;
1224 int error;
1225 struct rb_node **rb_link, *rb_parent;
1226 unsigned long charged = 0;
1227 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1228
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 /* Clear old maps */
1230 error = -ENOMEM;
1231munmap_back:
1232 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1233 if (vma && vma->vm_start < addr + len) {
1234 if (do_munmap(mm, addr, len))
1235 return -ENOMEM;
1236 goto munmap_back;
1237 }
1238
1239 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001240 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 return -ENOMEM;
1242
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001243 /*
1244 * Set 'VM_NORESERVE' if we should not account for the
Mel Gorman5a6fe122009-02-10 14:02:27 +00001245 * memory use of this mapping.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001246 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001247 if ((flags & MAP_NORESERVE)) {
1248 /* We honor MAP_NORESERVE if allowed to overcommit */
1249 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1250 vm_flags |= VM_NORESERVE;
1251
1252 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1253 if (file && is_file_hugepages(file))
1254 vm_flags |= VM_NORESERVE;
1255 }
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001256
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001257 /*
1258 * Private writable mapping: check memory availability
1259 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001260 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001261 charged = len >> PAGE_SHIFT;
1262 if (security_vm_enough_memory(charged))
1263 return -ENOMEM;
1264 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 }
1266
1267 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001268 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001270 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1271 if (vma)
1272 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
1274 /*
1275 * Determine the object being mapped and call the appropriate
1276 * specific mapper. the address has already been validated, but
1277 * not unmapped, but the maps are removed from the list.
1278 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001279 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 if (!vma) {
1281 error = -ENOMEM;
1282 goto unacct_error;
1283 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284
1285 vma->vm_mm = mm;
1286 vma->vm_start = addr;
1287 vma->vm_end = addr + len;
1288 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001289 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001291 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292
1293 if (file) {
1294 error = -EINVAL;
1295 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1296 goto free_vma;
1297 if (vm_flags & VM_DENYWRITE) {
1298 error = deny_write_access(file);
1299 if (error)
1300 goto free_vma;
1301 correct_wcount = 1;
1302 }
1303 vma->vm_file = file;
1304 get_file(file);
1305 error = file->f_op->mmap(file, vma);
1306 if (error)
1307 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001308 if (vm_flags & VM_EXECUTABLE)
1309 added_exe_file_vma(mm);
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001310
1311 /* Can addr have changed??
1312 *
1313 * Answer: Yes, several device drivers can do it in their
1314 * f_op->mmap method. -DaveM
1315 */
1316 addr = vma->vm_start;
1317 pgoff = vma->vm_pgoff;
1318 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 } else if (vm_flags & VM_SHARED) {
1320 error = shmem_zero_setup(vma);
1321 if (error)
1322 goto free_vma;
1323 }
1324
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001325 if (vma_wants_writenotify(vma)) {
1326 pgprot_t pprot = vma->vm_page_prot;
1327
1328 /* Can vma->vm_page_prot have changed??
1329 *
1330 * Answer: Yes, drivers may have changed it in their
1331 * f_op->mmap method.
1332 *
1333 * Ensures that vmas marked as uncached stay that way.
1334 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001335 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001336 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1337 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1338 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001339
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001340 vma_link(mm, vma, prev, rb_link, rb_parent);
1341 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001342
1343 /* Once vma denies write, undo our temporary denial count */
1344 if (correct_wcount)
1345 atomic_inc(&inode->i_writecount);
1346out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001347 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001348
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001350 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 if (vm_flags & VM_LOCKED) {
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001352 if (!mlock_vma_pages_range(vma, addr, addr + len))
1353 mm->locked_vm += (len >> PAGE_SHIFT);
Rik van Rielba470de2008-10-18 20:26:50 -07001354 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
Nick Piggin54cb8822007-07-19 01:46:59 -07001355 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 return addr;
1357
1358unmap_and_free_vma:
1359 if (correct_wcount)
1360 atomic_inc(&inode->i_writecount);
1361 vma->vm_file = NULL;
1362 fput(file);
1363
1364 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001365 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1366 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367free_vma:
1368 kmem_cache_free(vm_area_cachep, vma);
1369unacct_error:
1370 if (charged)
1371 vm_unacct_memory(charged);
1372 return error;
1373}
1374
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375/* Get an address range which is currently unmapped.
1376 * For shmat() with addr=0.
1377 *
1378 * Ugly calling convention alert:
1379 * Return value with the low bits set means error value,
1380 * ie
1381 * if (ret & ~PAGE_MASK)
1382 * error = ret;
1383 *
1384 * This function "knows" that -ENOMEM has the bits set.
1385 */
1386#ifndef HAVE_ARCH_UNMAPPED_AREA
1387unsigned long
1388arch_get_unmapped_area(struct file *filp, unsigned long addr,
1389 unsigned long len, unsigned long pgoff, unsigned long flags)
1390{
1391 struct mm_struct *mm = current->mm;
1392 struct vm_area_struct *vma;
1393 unsigned long start_addr;
1394
1395 if (len > TASK_SIZE)
1396 return -ENOMEM;
1397
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001398 if (flags & MAP_FIXED)
1399 return addr;
1400
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 if (addr) {
1402 addr = PAGE_ALIGN(addr);
1403 vma = find_vma(mm, addr);
1404 if (TASK_SIZE - len >= addr &&
1405 (!vma || addr + len <= vma->vm_start))
1406 return addr;
1407 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001408 if (len > mm->cached_hole_size) {
1409 start_addr = addr = mm->free_area_cache;
1410 } else {
1411 start_addr = addr = TASK_UNMAPPED_BASE;
1412 mm->cached_hole_size = 0;
1413 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
1415full_search:
1416 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1417 /* At this point: (!vma || addr < vma->vm_end). */
1418 if (TASK_SIZE - len < addr) {
1419 /*
1420 * Start a new search - just in case we missed
1421 * some holes.
1422 */
1423 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001424 addr = TASK_UNMAPPED_BASE;
1425 start_addr = addr;
1426 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 goto full_search;
1428 }
1429 return -ENOMEM;
1430 }
1431 if (!vma || addr + len <= vma->vm_start) {
1432 /*
1433 * Remember the place where we stopped the search:
1434 */
1435 mm->free_area_cache = addr + len;
1436 return addr;
1437 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001438 if (addr + mm->cached_hole_size < vma->vm_start)
1439 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 addr = vma->vm_end;
1441 }
1442}
1443#endif
1444
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001445void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446{
1447 /*
1448 * Is this a new hole at the lowest possible address?
1449 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001450 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1451 mm->free_area_cache = addr;
1452 mm->cached_hole_size = ~0UL;
1453 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454}
1455
1456/*
1457 * This mmap-allocator allocates new areas top-down from below the
1458 * stack's low limit (the base):
1459 */
1460#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1461unsigned long
1462arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1463 const unsigned long len, const unsigned long pgoff,
1464 const unsigned long flags)
1465{
1466 struct vm_area_struct *vma;
1467 struct mm_struct *mm = current->mm;
1468 unsigned long addr = addr0;
1469
1470 /* requested length too big for entire address space */
1471 if (len > TASK_SIZE)
1472 return -ENOMEM;
1473
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001474 if (flags & MAP_FIXED)
1475 return addr;
1476
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 /* requesting a specific address */
1478 if (addr) {
1479 addr = PAGE_ALIGN(addr);
1480 vma = find_vma(mm, addr);
1481 if (TASK_SIZE - len >= addr &&
1482 (!vma || addr + len <= vma->vm_start))
1483 return addr;
1484 }
1485
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001486 /* check if free_area_cache is useful for us */
1487 if (len <= mm->cached_hole_size) {
1488 mm->cached_hole_size = 0;
1489 mm->free_area_cache = mm->mmap_base;
1490 }
1491
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 /* either no address requested or can't fit in requested address hole */
1493 addr = mm->free_area_cache;
1494
1495 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001496 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 vma = find_vma(mm, addr-len);
1498 if (!vma || addr <= vma->vm_start)
1499 /* remember the address as a hint for next time */
1500 return (mm->free_area_cache = addr-len);
1501 }
1502
Chris Wright73219d12005-06-21 17:14:52 -07001503 if (mm->mmap_base < len)
1504 goto bottomup;
1505
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506 addr = mm->mmap_base-len;
1507
1508 do {
1509 /*
1510 * Lookup failure means no vma is above this address,
1511 * else if new region fits below vma->vm_start,
1512 * return with success:
1513 */
1514 vma = find_vma(mm, addr);
1515 if (!vma || addr+len <= vma->vm_start)
1516 /* remember the address as a hint for next time */
1517 return (mm->free_area_cache = addr);
1518
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001519 /* remember the largest hole we saw so far */
1520 if (addr + mm->cached_hole_size < vma->vm_start)
1521 mm->cached_hole_size = vma->vm_start - addr;
1522
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 /* try just below the current vma->vm_start */
1524 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001525 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526
Chris Wright73219d12005-06-21 17:14:52 -07001527bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528 /*
1529 * A failed mmap() very likely causes application failure,
1530 * so fall back to the bottom-up function here. This scenario
1531 * can happen with large stack limits and large mmap()
1532 * allocations.
1533 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001534 mm->cached_hole_size = ~0UL;
1535 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1537 /*
1538 * Restore the topdown base:
1539 */
1540 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001541 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542
1543 return addr;
1544}
1545#endif
1546
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001547void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548{
1549 /*
1550 * Is this a new hole at the highest possible address?
1551 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001552 if (addr > mm->free_area_cache)
1553 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554
1555 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001556 if (mm->free_area_cache > mm->mmap_base)
1557 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558}
1559
1560unsigned long
1561get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1562 unsigned long pgoff, unsigned long flags)
1563{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001564 unsigned long (*get_area)(struct file *, unsigned long,
1565 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566
Al Viro9206de92009-12-03 15:23:11 -05001567 unsigned long error = arch_mmap_check(addr, len, flags);
1568 if (error)
1569 return error;
1570
1571 /* Careful about overflows.. */
1572 if (len > TASK_SIZE)
1573 return -ENOMEM;
1574
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001575 get_area = current->mm->get_unmapped_area;
1576 if (file && file->f_op && file->f_op->get_unmapped_area)
1577 get_area = file->f_op->get_unmapped_area;
1578 addr = get_area(file, addr, len, pgoff, flags);
1579 if (IS_ERR_VALUE(addr))
1580 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001582 if (addr > TASK_SIZE - len)
1583 return -ENOMEM;
1584 if (addr & ~PAGE_MASK)
1585 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001586
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001587 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588}
1589
1590EXPORT_SYMBOL(get_unmapped_area);
1591
1592/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001593struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594{
1595 struct vm_area_struct *vma = NULL;
1596
1597 if (mm) {
1598 /* Check the cache first. */
1599 /* (Cache hit rate is typically around 35%.) */
1600 vma = mm->mmap_cache;
1601 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1602 struct rb_node * rb_node;
1603
1604 rb_node = mm->mm_rb.rb_node;
1605 vma = NULL;
1606
1607 while (rb_node) {
1608 struct vm_area_struct * vma_tmp;
1609
1610 vma_tmp = rb_entry(rb_node,
1611 struct vm_area_struct, vm_rb);
1612
1613 if (vma_tmp->vm_end > addr) {
1614 vma = vma_tmp;
1615 if (vma_tmp->vm_start <= addr)
1616 break;
1617 rb_node = rb_node->rb_left;
1618 } else
1619 rb_node = rb_node->rb_right;
1620 }
1621 if (vma)
1622 mm->mmap_cache = vma;
1623 }
1624 }
1625 return vma;
1626}
1627
1628EXPORT_SYMBOL(find_vma);
1629
1630/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1631struct vm_area_struct *
1632find_vma_prev(struct mm_struct *mm, unsigned long addr,
1633 struct vm_area_struct **pprev)
1634{
1635 struct vm_area_struct *vma = NULL, *prev = NULL;
ZhenwenXu48aae422009-01-06 14:40:21 -08001636 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637 if (!mm)
1638 goto out;
1639
1640 /* Guard against addr being lower than the first VMA */
1641 vma = mm->mmap;
1642
1643 /* Go through the RB tree quickly. */
1644 rb_node = mm->mm_rb.rb_node;
1645
1646 while (rb_node) {
1647 struct vm_area_struct *vma_tmp;
1648 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1649
1650 if (addr < vma_tmp->vm_end) {
1651 rb_node = rb_node->rb_left;
1652 } else {
1653 prev = vma_tmp;
1654 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1655 break;
1656 rb_node = rb_node->rb_right;
1657 }
1658 }
1659
1660out:
1661 *pprev = prev;
1662 return prev ? prev->vm_next : vma;
1663}
1664
1665/*
1666 * Verify that the stack growth is acceptable and
1667 * update accounting. This is shared with both the
1668 * grow-up and grow-down cases.
1669 */
ZhenwenXu48aae422009-01-06 14:40:21 -08001670static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671{
1672 struct mm_struct *mm = vma->vm_mm;
1673 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001674 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675
1676 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001677 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001678 return -ENOMEM;
1679
1680 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08001681 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682 return -ENOMEM;
1683
1684 /* mlock limit tests */
1685 if (vma->vm_flags & VM_LOCKED) {
1686 unsigned long locked;
1687 unsigned long limit;
1688 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001689 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
1690 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 if (locked > limit && !capable(CAP_IPC_LOCK))
1692 return -ENOMEM;
1693 }
1694
Adam Litke0d59a012007-01-30 14:35:39 -08001695 /* Check to ensure the stack will not grow into a hugetlb-only region */
1696 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1697 vma->vm_end - size;
1698 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1699 return -EFAULT;
1700
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 /*
1702 * Overcommit.. This must be the final test, as it will
1703 * update security statistics.
1704 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01001705 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 return -ENOMEM;
1707
1708 /* Ok, everything looks good - let it rip */
1709 mm->total_vm += grow;
1710 if (vma->vm_flags & VM_LOCKED)
1711 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001712 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 return 0;
1714}
1715
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001716#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001718 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1719 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001721int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722{
1723 int error;
1724
1725 if (!(vma->vm_flags & VM_GROWSUP))
1726 return -EFAULT;
1727
1728 /*
1729 * We must make sure the anon_vma is allocated
1730 * so that the anon_vma locking is not a noop.
1731 */
1732 if (unlikely(anon_vma_prepare(vma)))
1733 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07001734 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735
1736 /*
1737 * vma->vm_start/vm_end cannot change under us because the caller
1738 * is required to hold the mmap_sem in read mode. We need the
1739 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001740 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 */
Helge Deller06b32f32006-12-19 19:28:33 +01001742 if (address < PAGE_ALIGN(address+4))
1743 address = PAGE_ALIGN(address+4);
1744 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07001745 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01001746 return -ENOMEM;
1747 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 error = 0;
1749
1750 /* Somebody else might have raced and expanded it already */
1751 if (address > vma->vm_end) {
1752 unsigned long size, grow;
1753
1754 size = address - vma->vm_start;
1755 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1756
1757 error = acct_stack_growth(vma, size, grow);
Eric B Munson3af9e852010-05-18 15:30:49 +01001758 if (!error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 vma->vm_end = address;
Eric B Munson3af9e852010-05-18 15:30:49 +01001760 perf_event_mmap(vma);
1761 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001763 vma_unlock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 return error;
1765}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001766#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1767
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768/*
1769 * vma is the first one with address < vma->vm_start. Have to extend vma.
1770 */
Denys Vlasenkocb8f4882008-10-18 20:27:01 -07001771static int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001772 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773{
1774 int error;
1775
1776 /*
1777 * We must make sure the anon_vma is allocated
1778 * so that the anon_vma locking is not a noop.
1779 */
1780 if (unlikely(anon_vma_prepare(vma)))
1781 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001782
1783 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001784 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001785 if (error)
1786 return error;
1787
Rik van Rielbb4a3402010-08-09 17:18:37 -07001788 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789
1790 /*
1791 * vma->vm_start/vm_end cannot change under us because the caller
1792 * is required to hold the mmap_sem in read mode. We need the
1793 * anon_vma lock to serialize against concurrent expand_stacks.
1794 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795
1796 /* Somebody else might have raced and expanded it already */
1797 if (address < vma->vm_start) {
1798 unsigned long size, grow;
1799
1800 size = vma->vm_end - address;
1801 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1802
1803 error = acct_stack_growth(vma, size, grow);
1804 if (!error) {
1805 vma->vm_start = address;
1806 vma->vm_pgoff -= grow;
Eric B Munson3af9e852010-05-18 15:30:49 +01001807 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 }
1809 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001810 vma_unlock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811 return error;
1812}
1813
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001814int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1815{
1816 return expand_downwards(vma, address);
1817}
1818
1819#ifdef CONFIG_STACK_GROWSUP
1820int expand_stack(struct vm_area_struct *vma, unsigned long address)
1821{
1822 return expand_upwards(vma, address);
1823}
1824
1825struct vm_area_struct *
1826find_extend_vma(struct mm_struct *mm, unsigned long addr)
1827{
1828 struct vm_area_struct *vma, *prev;
1829
1830 addr &= PAGE_MASK;
1831 vma = find_vma_prev(mm, addr, &prev);
1832 if (vma && (vma->vm_start <= addr))
1833 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01001834 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001835 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001836 if (prev->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001837 mlock_vma_pages_range(prev, addr, prev->vm_end);
Rik van Rielba470de2008-10-18 20:26:50 -07001838 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001839 return prev;
1840}
1841#else
1842int expand_stack(struct vm_area_struct *vma, unsigned long address)
1843{
1844 return expand_downwards(vma, address);
1845}
1846
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847struct vm_area_struct *
1848find_extend_vma(struct mm_struct * mm, unsigned long addr)
1849{
1850 struct vm_area_struct * vma;
1851 unsigned long start;
1852
1853 addr &= PAGE_MASK;
1854 vma = find_vma(mm,addr);
1855 if (!vma)
1856 return NULL;
1857 if (vma->vm_start <= addr)
1858 return vma;
1859 if (!(vma->vm_flags & VM_GROWSDOWN))
1860 return NULL;
1861 start = vma->vm_start;
1862 if (expand_stack(vma, addr))
1863 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001864 if (vma->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001865 mlock_vma_pages_range(vma, addr, start);
Rik van Rielba470de2008-10-18 20:26:50 -07001866 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 return vma;
1868}
1869#endif
1870
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001872 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001874 *
1875 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001877static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001879 /* Update high watermark before we lower total_vm */
1880 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001882 long nrpages = vma_pages(vma);
1883
1884 mm->total_vm -= nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001885 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001886 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001887 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 validate_mm(mm);
1889}
1890
1891/*
1892 * Get rid of page table information in the indicated region.
1893 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001894 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 */
1896static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001897 struct vm_area_struct *vma, struct vm_area_struct *prev,
1898 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001899{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001900 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 struct mmu_gather *tlb;
1902 unsigned long nr_accounted = 0;
1903
1904 lru_add_drain();
1905 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001906 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001907 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 vm_unacct_memory(nr_accounted);
Jan Beulich42b77722008-07-23 21:27:10 -07001909 free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001910 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 tlb_finish_mmu(tlb, start, end);
1912}
1913
1914/*
1915 * Create a list of vma's touched by the unmap, removing them from the mm's
1916 * vma list as we go..
1917 */
1918static void
1919detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1920 struct vm_area_struct *prev, unsigned long end)
1921{
1922 struct vm_area_struct **insertion_point;
1923 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001924 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925
1926 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001927 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928 do {
1929 rb_erase(&vma->vm_rb, &mm->mm_rb);
1930 mm->map_count--;
1931 tail_vma = vma;
1932 vma = vma->vm_next;
1933 } while (vma && vma->vm_start < end);
1934 *insertion_point = vma;
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001935 if (vma)
1936 vma->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001938 if (mm->unmap_area == arch_unmap_area)
1939 addr = prev ? prev->vm_end : mm->mmap_base;
1940 else
1941 addr = vma ? vma->vm_start : mm->mmap_base;
1942 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 mm->mmap_cache = NULL; /* Kill the cache. */
1944}
1945
1946/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001947 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
1948 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001950static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951 unsigned long addr, int new_below)
1952{
1953 struct mempolicy *pol;
1954 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08001955 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956
Andi Kleena5516432008-07-23 21:27:41 -07001957 if (is_vm_hugetlb_page(vma) && (addr &
1958 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959 return -EINVAL;
1960
Christoph Lametere94b1762006-12-06 20:33:17 -08001961 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08001963 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964
1965 /* most fields are the same, copy all, and then fixup */
1966 *new = *vma;
1967
Rik van Riel5beb4932010-03-05 13:42:07 -08001968 INIT_LIST_HEAD(&new->anon_vma_chain);
1969
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 if (new_below)
1971 new->vm_end = addr;
1972 else {
1973 new->vm_start = addr;
1974 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1975 }
1976
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001977 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 if (IS_ERR(pol)) {
Rik van Riel5beb4932010-03-05 13:42:07 -08001979 err = PTR_ERR(pol);
1980 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981 }
1982 vma_set_policy(new, pol);
1983
Rik van Riel5beb4932010-03-05 13:42:07 -08001984 if (anon_vma_clone(new, vma))
1985 goto out_free_mpol;
1986
Matt Helsley925d1c42008-04-29 01:01:36 -07001987 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001989 if (vma->vm_flags & VM_EXECUTABLE)
1990 added_exe_file_vma(mm);
1991 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992
1993 if (new->vm_ops && new->vm_ops->open)
1994 new->vm_ops->open(new);
1995
1996 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08001997 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1999 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002000 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001
Rik van Riel5beb4932010-03-05 13:42:07 -08002002 /* Success. */
2003 if (!err)
2004 return 0;
2005
2006 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002007 if (new->vm_ops && new->vm_ops->close)
2008 new->vm_ops->close(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002009 if (new->vm_file) {
2010 if (vma->vm_flags & VM_EXECUTABLE)
2011 removed_exe_file_vma(mm);
2012 fput(new->vm_file);
2013 }
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002014 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002015 out_free_mpol:
2016 mpol_put(pol);
2017 out_free_vma:
2018 kmem_cache_free(vm_area_cachep, new);
2019 out_err:
2020 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021}
2022
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002023/*
2024 * Split a vma into two pieces at address 'addr', a new vma is allocated
2025 * either for the first part or the tail.
2026 */
2027int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2028 unsigned long addr, int new_below)
2029{
2030 if (mm->map_count >= sysctl_max_map_count)
2031 return -ENOMEM;
2032
2033 return __split_vma(mm, vma, addr, new_below);
2034}
2035
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036/* Munmap is split into 2 main parts -- this part which finds
2037 * what needs doing, and the areas themselves, which do the
2038 * work. This now handles partial unmappings.
2039 * Jeremy Fitzhardinge <jeremy@goop.org>
2040 */
2041int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2042{
2043 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002044 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002045
2046 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2047 return -EINVAL;
2048
2049 if ((len = PAGE_ALIGN(len)) == 0)
2050 return -EINVAL;
2051
2052 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07002053 vma = find_vma_prev(mm, start, &prev);
2054 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07002056 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057
2058 /* if it doesn't overlap, we have nothing.. */
2059 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002060 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061 return 0;
2062
2063 /*
2064 * If we need to split any vma, do it now to save pain later.
2065 *
2066 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2067 * unmapped vm_area_struct will remain in use: so lower split_vma
2068 * places tmp vma above, and higher split_vma places tmp vma below.
2069 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002070 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002071 int error;
2072
2073 /*
2074 * Make sure that map_count on return from munmap() will
2075 * not exceed its limit; but let map_count go just above
2076 * its limit temporarily, to help free resources as expected.
2077 */
2078 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2079 return -ENOMEM;
2080
2081 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002082 if (error)
2083 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002084 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085 }
2086
2087 /* Does it split the last one? */
2088 last = find_vma(mm, end);
2089 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002090 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002091 if (error)
2092 return error;
2093 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002094 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095
2096 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002097 * unlock any mlock()ed ranges before detaching vmas
2098 */
2099 if (mm->locked_vm) {
2100 struct vm_area_struct *tmp = vma;
2101 while (tmp && tmp->vm_start < end) {
2102 if (tmp->vm_flags & VM_LOCKED) {
2103 mm->locked_vm -= vma_pages(tmp);
2104 munlock_vma_pages_all(tmp);
2105 }
2106 tmp = tmp->vm_next;
2107 }
2108 }
2109
2110 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 * Remove the vma's, and unmap the actual pages
2112 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002113 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2114 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115
2116 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002117 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118
2119 return 0;
2120}
2121
2122EXPORT_SYMBOL(do_munmap);
2123
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002124SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125{
2126 int ret;
2127 struct mm_struct *mm = current->mm;
2128
2129 profile_munmap(addr);
2130
2131 down_write(&mm->mmap_sem);
2132 ret = do_munmap(mm, addr, len);
2133 up_write(&mm->mmap_sem);
2134 return ret;
2135}
2136
2137static inline void verify_mm_writelocked(struct mm_struct *mm)
2138{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002139#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2141 WARN_ON(1);
2142 up_read(&mm->mmap_sem);
2143 }
2144#endif
2145}
2146
2147/*
2148 * this is really a simplified "do_mmap". it only handles
2149 * anonymous maps. eventually we may be able to do some
2150 * brk-specific accounting here.
2151 */
2152unsigned long do_brk(unsigned long addr, unsigned long len)
2153{
2154 struct mm_struct * mm = current->mm;
2155 struct vm_area_struct * vma, * prev;
2156 unsigned long flags;
2157 struct rb_node ** rb_link, * rb_parent;
2158 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002159 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160
2161 len = PAGE_ALIGN(len);
2162 if (!len)
2163 return addr;
2164
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01002165 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05002166 if (error)
2167 return error;
2168
Kirill Korotaev3a459752006-09-07 14:17:04 +04002169 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2170
Al Viro2c6a10162009-12-03 19:40:46 -05002171 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2172 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002173 return error;
2174
Linus Torvalds1da177e2005-04-16 15:20:36 -07002175 /*
2176 * mlock MCL_FUTURE?
2177 */
2178 if (mm->def_flags & VM_LOCKED) {
2179 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002180 locked = len >> PAGE_SHIFT;
2181 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002182 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002183 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2185 return -EAGAIN;
2186 }
2187
2188 /*
2189 * mm->mmap_sem is required to protect against another thread
2190 * changing the mappings in case we sleep.
2191 */
2192 verify_mm_writelocked(mm);
2193
2194 /*
2195 * Clear old maps. this also does some error checking for us
2196 */
2197 munmap_back:
2198 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2199 if (vma && vma->vm_start < addr + len) {
2200 if (do_munmap(mm, addr, len))
2201 return -ENOMEM;
2202 goto munmap_back;
2203 }
2204
2205 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002206 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 return -ENOMEM;
2208
2209 if (mm->map_count > sysctl_max_map_count)
2210 return -ENOMEM;
2211
2212 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2213 return -ENOMEM;
2214
Linus Torvalds1da177e2005-04-16 15:20:36 -07002215 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002216 vma = vma_merge(mm, prev, addr, addr + len, flags,
2217 NULL, NULL, pgoff, NULL);
2218 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002219 goto out;
2220
2221 /*
2222 * create a vma struct for an anonymous mapping
2223 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002224 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225 if (!vma) {
2226 vm_unacct_memory(len >> PAGE_SHIFT);
2227 return -ENOMEM;
2228 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229
Rik van Riel5beb4932010-03-05 13:42:07 -08002230 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 vma->vm_mm = mm;
2232 vma->vm_start = addr;
2233 vma->vm_end = addr + len;
2234 vma->vm_pgoff = pgoff;
2235 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002236 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237 vma_link(mm, vma, prev, rb_link, rb_parent);
2238out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002239 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240 mm->total_vm += len >> PAGE_SHIFT;
2241 if (flags & VM_LOCKED) {
Rik van Rielba470de2008-10-18 20:26:50 -07002242 if (!mlock_vma_pages_range(vma, addr, addr + len))
2243 mm->locked_vm += (len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244 }
2245 return addr;
2246}
2247
2248EXPORT_SYMBOL(do_brk);
2249
2250/* Release all mmaps. */
2251void exit_mmap(struct mm_struct *mm)
2252{
2253 struct mmu_gather *tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002254 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002255 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002256 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002258 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002259 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002260
Rik van Rielba470de2008-10-18 20:26:50 -07002261 if (mm->locked_vm) {
2262 vma = mm->mmap;
2263 while (vma) {
2264 if (vma->vm_flags & VM_LOCKED)
2265 munlock_vma_pages_all(vma);
2266 vma = vma->vm_next;
2267 }
2268 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002269
2270 arch_exit_mmap(mm);
2271
Rik van Rielba470de2008-10-18 20:26:50 -07002272 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002273 if (!vma) /* Can happen if dup_mmap() received an OOM */
2274 return;
2275
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002278 tlb = tlb_gather_mmu(mm, 1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002279 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002280 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002281 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 vm_unacct_memory(nr_accounted);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002283
Jan Beulich42b77722008-07-23 21:27:10 -07002284 free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002285 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002288 * Walk the list again, actually closing and freeing it,
2289 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002290 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002291 while (vma)
2292 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002293
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002294 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295}
2296
2297/* Insert vm structure into process list sorted by address
2298 * and into the inode's i_mmap tree. If vm_file is non-NULL
2299 * then i_mmap_lock is taken here.
2300 */
2301int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2302{
2303 struct vm_area_struct * __vma, * prev;
2304 struct rb_node ** rb_link, * rb_parent;
2305
2306 /*
2307 * The vm_pgoff of a purely anonymous vma should be irrelevant
2308 * until its first write fault, when page's anon_vma and index
2309 * are set. But now set the vm_pgoff it will almost certainly
2310 * end up with (unless mremap moves it elsewhere before that
2311 * first wfault), so /proc/pid/maps tells a consistent story.
2312 *
2313 * By setting it to reflect the virtual start address of the
2314 * vma, merges and splits can happen in a seamless way, just
2315 * using the existing file pgoff checks and manipulations.
2316 * Similarly in do_mmap_pgoff and in do_brk.
2317 */
2318 if (!vma->vm_file) {
2319 BUG_ON(vma->anon_vma);
2320 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2321 }
2322 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2323 if (__vma && __vma->vm_start < vma->vm_end)
2324 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002325 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002326 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002327 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 vma_link(mm, vma, prev, rb_link, rb_parent);
2329 return 0;
2330}
2331
2332/*
2333 * Copy the vma structure to a new location in the same mm,
2334 * prior to moving page table entries, to effect an mremap move.
2335 */
2336struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2337 unsigned long addr, unsigned long len, pgoff_t pgoff)
2338{
2339 struct vm_area_struct *vma = *vmap;
2340 unsigned long vma_start = vma->vm_start;
2341 struct mm_struct *mm = vma->vm_mm;
2342 struct vm_area_struct *new_vma, *prev;
2343 struct rb_node **rb_link, *rb_parent;
2344 struct mempolicy *pol;
2345
2346 /*
2347 * If anonymous vma has not yet been faulted, update new pgoff
2348 * to match new location, to increase its chance of merging.
2349 */
2350 if (!vma->vm_file && !vma->anon_vma)
2351 pgoff = addr >> PAGE_SHIFT;
2352
2353 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2354 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2355 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2356 if (new_vma) {
2357 /*
2358 * Source vma may have been merged into new_vma
2359 */
2360 if (vma_start >= new_vma->vm_start &&
2361 vma_start < new_vma->vm_end)
2362 *vmap = new_vma;
2363 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002364 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 if (new_vma) {
2366 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002367 pol = mpol_dup(vma_policy(vma));
Rik van Riel5beb4932010-03-05 13:42:07 -08002368 if (IS_ERR(pol))
2369 goto out_free_vma;
2370 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2371 if (anon_vma_clone(new_vma, vma))
2372 goto out_free_mempol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373 vma_set_policy(new_vma, pol);
2374 new_vma->vm_start = addr;
2375 new_vma->vm_end = addr + len;
2376 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002377 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002379 if (vma->vm_flags & VM_EXECUTABLE)
2380 added_exe_file_vma(mm);
2381 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382 if (new_vma->vm_ops && new_vma->vm_ops->open)
2383 new_vma->vm_ops->open(new_vma);
2384 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2385 }
2386 }
2387 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002388
2389 out_free_mempol:
2390 mpol_put(pol);
2391 out_free_vma:
2392 kmem_cache_free(vm_area_cachep, new_vma);
2393 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002394}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002395
2396/*
2397 * Return true if the calling process may expand its vm space by the passed
2398 * number of pages
2399 */
2400int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2401{
2402 unsigned long cur = mm->total_vm; /* pages */
2403 unsigned long lim;
2404
Jiri Slaby59e99e52010-03-05 13:41:44 -08002405 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002406
2407 if (cur + npages > lim)
2408 return 0;
2409 return 1;
2410}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002411
2412
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002413static int special_mapping_fault(struct vm_area_struct *vma,
2414 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002415{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002416 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002417 struct page **pages;
2418
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002419 /*
2420 * special mappings have no vm_file, and in that case, the mm
2421 * uses vm_pgoff internally. So we have to subtract it from here.
2422 * We are allowed to do this because we are the mm; do not copy
2423 * this code into drivers!
2424 */
2425 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002426
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002427 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2428 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002429
2430 if (*pages) {
2431 struct page *page = *pages;
2432 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002433 vmf->page = page;
2434 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002435 }
2436
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002437 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002438}
2439
2440/*
2441 * Having a close hook prevents vma merging regardless of flags.
2442 */
2443static void special_mapping_close(struct vm_area_struct *vma)
2444{
2445}
2446
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002447static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002448 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002449 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002450};
2451
2452/*
2453 * Called with mm->mmap_sem held for writing.
2454 * Insert a new vma covering the given region, with the given flags.
2455 * Its pages are supplied by the given array of struct page *.
2456 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2457 * The region past the last page supplied will always produce SIGBUS.
2458 * The array pointer and the pages it points to are assumed to stay alive
2459 * for as long as this mapping might exist.
2460 */
2461int install_special_mapping(struct mm_struct *mm,
2462 unsigned long addr, unsigned long len,
2463 unsigned long vm_flags, struct page **pages)
2464{
2465 struct vm_area_struct *vma;
2466
2467 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2468 if (unlikely(vma == NULL))
2469 return -ENOMEM;
2470
Rik van Riel5beb4932010-03-05 13:42:07 -08002471 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002472 vma->vm_mm = mm;
2473 vma->vm_start = addr;
2474 vma->vm_end = addr + len;
2475
Nick Piggin2f987352008-02-02 03:08:53 +01002476 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002477 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002478
2479 vma->vm_ops = &special_mapping_vmops;
2480 vma->vm_private_data = pages;
2481
2482 if (unlikely(insert_vm_struct(mm, vma))) {
2483 kmem_cache_free(vm_area_cachep, vma);
2484 return -ENOMEM;
2485 }
2486
2487 mm->total_vm += len >> PAGE_SHIFT;
2488
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002489 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002490
Roland McGrathfa5dc222007-02-08 14:20:41 -08002491 return 0;
2492}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002493
2494static DEFINE_MUTEX(mm_all_locks_mutex);
2495
Peter Zijlstra454ed842008-08-11 09:30:25 +02002496static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002497{
Rik van Riel012f1802010-08-09 17:18:40 -07002498 if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002499 /*
2500 * The LSB of head.next can't change from under us
2501 * because we hold the mm_all_locks_mutex.
2502 */
Rik van Riel012f1802010-08-09 17:18:40 -07002503 spin_lock_nest_lock(&anon_vma->root->lock, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002504 /*
2505 * We can safely modify head.next after taking the
Rik van Riel012f1802010-08-09 17:18:40 -07002506 * anon_vma->root->lock. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002507 * the same anon_vma we won't take it again.
2508 *
2509 * No need of atomic instructions here, head.next
2510 * can't change from under us thanks to the
Rik van Riel012f1802010-08-09 17:18:40 -07002511 * anon_vma->root->lock.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002512 */
2513 if (__test_and_set_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002514 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002515 BUG();
2516 }
2517}
2518
Peter Zijlstra454ed842008-08-11 09:30:25 +02002519static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002520{
2521 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2522 /*
2523 * AS_MM_ALL_LOCKS can't change from under us because
2524 * we hold the mm_all_locks_mutex.
2525 *
2526 * Operations on ->flags have to be atomic because
2527 * even if AS_MM_ALL_LOCKS is stable thanks to the
2528 * mm_all_locks_mutex, there may be other cpus
2529 * changing other bitflags in parallel to us.
2530 */
2531 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2532 BUG();
Peter Zijlstra454ed842008-08-11 09:30:25 +02002533 spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002534 }
2535}
2536
2537/*
2538 * This operation locks against the VM for all pte/vma/mm related
2539 * operations that could ever happen on a certain mm. This includes
2540 * vmtruncate, try_to_unmap, and all page faults.
2541 *
2542 * The caller must take the mmap_sem in write mode before calling
2543 * mm_take_all_locks(). The caller isn't allowed to release the
2544 * mmap_sem until mm_drop_all_locks() returns.
2545 *
2546 * mmap_sem in write mode is required in order to block all operations
2547 * that could modify pagetables and free pages without need of
2548 * altering the vma layout (for example populate_range() with
2549 * nonlinear vmas). It's also needed in write mode to avoid new
2550 * anon_vmas to be associated with existing vmas.
2551 *
2552 * A single task can't take more than one mm_take_all_locks() in a row
2553 * or it would deadlock.
2554 *
2555 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2556 * mapping->flags avoid to take the same lock twice, if more than one
2557 * vma in this mm is backed by the same anon_vma or address_space.
2558 *
2559 * We can take all the locks in random order because the VM code
2560 * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never
2561 * takes more than one of them in a row. Secondly we're protected
2562 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2563 *
2564 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2565 * that may have to take thousand of locks.
2566 *
2567 * mm_take_all_locks() can fail if it's interrupted by signals.
2568 */
2569int mm_take_all_locks(struct mm_struct *mm)
2570{
2571 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002572 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002573 int ret = -EINTR;
2574
2575 BUG_ON(down_read_trylock(&mm->mmap_sem));
2576
2577 mutex_lock(&mm_all_locks_mutex);
2578
2579 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2580 if (signal_pending(current))
2581 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002582 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02002583 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002584 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002585
2586 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2587 if (signal_pending(current))
2588 goto out_unlock;
2589 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002590 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2591 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002592 }
2593
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002594 ret = 0;
2595
2596out_unlock:
2597 if (ret)
2598 mm_drop_all_locks(mm);
2599
2600 return ret;
2601}
2602
2603static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2604{
Rik van Riel012f1802010-08-09 17:18:40 -07002605 if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002606 /*
2607 * The LSB of head.next can't change to 0 from under
2608 * us because we hold the mm_all_locks_mutex.
2609 *
2610 * We must however clear the bitflag before unlocking
2611 * the vma so the users using the anon_vma->head will
2612 * never see our bitflag.
2613 *
2614 * No need of atomic instructions here, head.next
2615 * can't change from under us until we release the
Rik van Riel012f1802010-08-09 17:18:40 -07002616 * anon_vma->root->lock.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002617 */
2618 if (!__test_and_clear_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002619 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002620 BUG();
Rik van Rielcba48b92010-08-09 17:18:38 -07002621 anon_vma_unlock(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002622 }
2623}
2624
2625static void vm_unlock_mapping(struct address_space *mapping)
2626{
2627 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2628 /*
2629 * AS_MM_ALL_LOCKS can't change to 0 from under us
2630 * because we hold the mm_all_locks_mutex.
2631 */
2632 spin_unlock(&mapping->i_mmap_lock);
2633 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2634 &mapping->flags))
2635 BUG();
2636 }
2637}
2638
2639/*
2640 * The mmap_sem cannot be released by the caller until
2641 * mm_drop_all_locks() returns.
2642 */
2643void mm_drop_all_locks(struct mm_struct *mm)
2644{
2645 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002646 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002647
2648 BUG_ON(down_read_trylock(&mm->mmap_sem));
2649 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2650
2651 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2652 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002653 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2654 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002655 if (vma->vm_file && vma->vm_file->f_mapping)
2656 vm_unlock_mapping(vma->vm_file->f_mapping);
2657 }
2658
2659 mutex_unlock(&mm_all_locks_mutex);
2660}
David Howells8feae132009-01-08 12:04:47 +00002661
2662/*
2663 * initialise the VMA slab
2664 */
2665void __init mmap_init(void)
2666{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07002667 int ret;
2668
2669 ret = percpu_counter_init(&vm_committed_as, 0);
2670 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00002671}