blob: bbdc9af5e1177108894d881126761fa71ef9cada [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
Alan Cox046c6882009-01-05 14:06:29 +00006 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
9#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070010#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070029#include <linux/mmu_notifier.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020030#include <linux/perf_event.h>
Al Viro120a7952010-10-30 02:54:44 -040031#include <linux/audit.h>
Andrea Arcangelib15d00b2011-01-13 15:46:59 -080032#include <linux/khugepaged.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#include <asm/uaccess.h>
35#include <asm/cacheflush.h>
36#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020037#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Jan Beulich42b77722008-07-23 21:27:10 -070039#include "internal.h"
40
Kirill Korotaev3a459752006-09-07 14:17:04 +040041#ifndef arch_mmap_check
42#define arch_mmap_check(addr, len, flags) (0)
43#endif
44
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080045#ifndef arch_rebalance_pgtables
46#define arch_rebalance_pgtables(addr, len) (addr)
47#endif
48
Hugh Dickinse0da3822005-04-19 13:29:15 -070049static void unmap_region(struct mm_struct *mm,
50 struct vm_area_struct *vma, struct vm_area_struct *prev,
51 unsigned long start, unsigned long end);
52
Linus Torvalds1da177e2005-04-16 15:20:36 -070053/*
54 * WARNING: the debugging will use recursive algorithms so never enable this
55 * unless you know what you are doing.
56 */
57#undef DEBUG_MM_RB
58
59/* description of effects of mapping type and prot in current implementation.
60 * this is due to the limited x86 page protection hardware. The expected
61 * behavior is in parens:
62 *
63 * map_type prot
64 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
65 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (yes) yes w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
70 * w: (no) no w: (no) no w: (copy) copy w: (no) no
71 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
72 *
73 */
74pgprot_t protection_map[16] = {
75 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
76 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
77};
78
Hugh Dickins804af2c2006-07-26 21:39:49 +010079pgprot_t vm_get_page_prot(unsigned long vm_flags)
80{
Dave Kleikampb845f312008-07-08 00:28:51 +100081 return __pgprot(pgprot_val(protection_map[vm_flags &
82 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
83 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010084}
85EXPORT_SYMBOL(vm_get_page_prot);
86
Shaohua Li34679d72011-05-24 17:11:18 -070087int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
88int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070089int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Shaohua Li34679d72011-05-24 17:11:18 -070090/*
91 * Make sure vm_committed_as in one cacheline and not cacheline shared with
92 * other variables. It can be updated by several CPUs frequently.
93 */
94struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96/*
97 * Check that a process has enough memory to allocate a new virtual
98 * mapping. 0 means there is enough memory for the allocation to
99 * succeed and -ENOMEM implies there is not.
100 *
101 * We currently support three overcommit policies, which are set via the
102 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
103 *
104 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
105 * Additional code 2002 Jul 20 by Robert Love.
106 *
107 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
108 *
109 * Note this is a helper function intended to be used by LSMs which
110 * wish to use this logic.
111 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700112int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 unsigned long free, allowed;
115
116 vm_acct_memory(pages);
117
118 /*
119 * Sometimes we want to use more memory than we have
120 */
121 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
122 return 0;
123
124 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
125 unsigned long n;
126
Christoph Lameter347ce432006-06-30 01:55:35 -0700127 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 free += nr_swap_pages;
129
130 /*
131 * Any slabs which are created with the
132 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
133 * which are reclaimable, under pressure. The dentry
134 * cache and most inode caches should fall into this
135 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700136 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138 /*
139 * Leave the last 3% for root
140 */
141 if (!cap_sys_admin)
142 free -= free / 32;
143
144 if (free > pages)
145 return 0;
146
147 /*
148 * nr_free_pages() is very expensive on large systems,
149 * only call if we're about to fail.
150 */
151 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700152
153 /*
154 * Leave reserved pages. The pages are not for anonymous pages.
155 */
156 if (n <= totalreserve_pages)
157 goto error;
158 else
159 n -= totalreserve_pages;
160
161 /*
162 * Leave the last 3% for root
163 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 if (!cap_sys_admin)
165 n -= n / 32;
166 free += n;
167
168 if (free > pages)
169 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700170
171 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 }
173
174 allowed = (totalram_pages - hugetlb_total_pages())
175 * sysctl_overcommit_ratio / 100;
176 /*
177 * Leave the last 3% for root
178 */
179 if (!cap_sys_admin)
180 allowed -= allowed / 32;
181 allowed += total_swap_pages;
182
183 /* Don't let a single process grow too big:
184 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -0700185 if (mm)
186 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700188 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700190error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 vm_unacct_memory(pages);
192
193 return -ENOMEM;
194}
195
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196/*
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700197 * Requires inode->i_mapping->i_mmap_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 */
199static void __remove_shared_vm_struct(struct vm_area_struct *vma,
200 struct file *file, struct address_space *mapping)
201{
202 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800203 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 if (vma->vm_flags & VM_SHARED)
205 mapping->i_mmap_writable--;
206
207 flush_dcache_mmap_lock(mapping);
208 if (unlikely(vma->vm_flags & VM_NONLINEAR))
209 list_del_init(&vma->shared.vm_set.list);
210 else
211 vma_prio_tree_remove(vma, &mapping->i_mmap);
212 flush_dcache_mmap_unlock(mapping);
213}
214
215/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700216 * Unlink a file-based vm structure from its prio_tree, to hide
217 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700219void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
221 struct file *file = vma->vm_file;
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 if (file) {
224 struct address_space *mapping = file->f_mapping;
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700225 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 __remove_shared_vm_struct(vma, file, mapping);
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700227 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700229}
230
231/*
232 * Close a vm structure and free it, returning the next.
233 */
234static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
235{
236 struct vm_area_struct *next = vma->vm_next;
237
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700238 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 if (vma->vm_ops && vma->vm_ops->close)
240 vma->vm_ops->close(vma);
Matt Helsley925d1c42008-04-29 01:01:36 -0700241 if (vma->vm_file) {
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700242 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700243 if (vma->vm_flags & VM_EXECUTABLE)
244 removed_exe_file_vma(vma->vm_mm);
245 }
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700246 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700248 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249}
250
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100251SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
253 unsigned long rlim, retval;
254 unsigned long newbrk, oldbrk;
255 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700256 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258 down_write(&mm->mmap_sem);
259
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700260#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800261 /*
262 * CONFIG_COMPAT_BRK can still be overridden by setting
263 * randomize_va_space to 2, which will still cause mm->start_brk
264 * to be arbitrarily shifted
265 */
Jiri Kosina4471a672011-04-14 15:22:09 -0700266 if (current->brk_randomized)
Jiri Kosina5520e892011-01-13 15:47:23 -0800267 min_brk = mm->start_brk;
268 else
269 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700270#else
271 min_brk = mm->start_brk;
272#endif
273 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700275
276 /*
277 * Check against rlimit here. If this check is done later after the test
278 * of oldbrk with newbrk then it can escape the test and let the data
279 * segment grow beyond its set limit the in case where the limit is
280 * not page aligned -Ram Gupta
281 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800282 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100283 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
284 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700285 goto out;
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 newbrk = PAGE_ALIGN(brk);
288 oldbrk = PAGE_ALIGN(mm->brk);
289 if (oldbrk == newbrk)
290 goto set_brk;
291
292 /* Always allow shrinking brk. */
293 if (brk <= mm->brk) {
294 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
295 goto set_brk;
296 goto out;
297 }
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 /* Check against existing mmap mappings. */
300 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
301 goto out;
302
303 /* Ok, looks good - let it rip. */
304 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
305 goto out;
306set_brk:
307 mm->brk = brk;
308out:
309 retval = mm->brk;
310 up_write(&mm->mmap_sem);
311 return retval;
312}
313
314#ifdef DEBUG_MM_RB
315static int browse_rb(struct rb_root *root)
316{
317 int i = 0, j;
318 struct rb_node *nd, *pn = NULL;
319 unsigned long prev = 0, pend = 0;
320
321 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
322 struct vm_area_struct *vma;
323 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
324 if (vma->vm_start < prev)
325 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
326 if (vma->vm_start < pend)
327 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
328 if (vma->vm_start > vma->vm_end)
329 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
330 i++;
331 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800332 prev = vma->vm_start;
333 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 }
335 j = 0;
336 for (nd = pn; nd; nd = rb_prev(nd)) {
337 j++;
338 }
339 if (i != j)
340 printk("backwards %d, forwards %d\n", j, i), i = 0;
341 return i;
342}
343
344void validate_mm(struct mm_struct *mm)
345{
346 int bug = 0;
347 int i = 0;
348 struct vm_area_struct *tmp = mm->mmap;
349 while (tmp) {
350 tmp = tmp->vm_next;
351 i++;
352 }
353 if (i != mm->map_count)
354 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
355 i = browse_rb(&mm->mm_rb);
356 if (i != mm->map_count)
357 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200358 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359}
360#else
361#define validate_mm(mm) do { } while (0)
362#endif
363
364static struct vm_area_struct *
365find_vma_prepare(struct mm_struct *mm, unsigned long addr,
366 struct vm_area_struct **pprev, struct rb_node ***rb_link,
367 struct rb_node ** rb_parent)
368{
369 struct vm_area_struct * vma;
370 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
371
372 __rb_link = &mm->mm_rb.rb_node;
373 rb_prev = __rb_parent = NULL;
374 vma = NULL;
375
376 while (*__rb_link) {
377 struct vm_area_struct *vma_tmp;
378
379 __rb_parent = *__rb_link;
380 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
381
382 if (vma_tmp->vm_end > addr) {
383 vma = vma_tmp;
384 if (vma_tmp->vm_start <= addr)
Benny Halevydfe195f2008-08-05 13:01:41 -0700385 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 __rb_link = &__rb_parent->rb_left;
387 } else {
388 rb_prev = __rb_parent;
389 __rb_link = &__rb_parent->rb_right;
390 }
391 }
392
393 *pprev = NULL;
394 if (rb_prev)
395 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
396 *rb_link = __rb_link;
397 *rb_parent = __rb_parent;
398 return vma;
399}
400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
402 struct rb_node **rb_link, struct rb_node *rb_parent)
403{
404 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
405 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
406}
407
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700408static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409{
ZhenwenXu48aae422009-01-06 14:40:21 -0800410 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
412 file = vma->vm_file;
413 if (file) {
414 struct address_space *mapping = file->f_mapping;
415
416 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800417 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (vma->vm_flags & VM_SHARED)
419 mapping->i_mmap_writable++;
420
421 flush_dcache_mmap_lock(mapping);
422 if (unlikely(vma->vm_flags & VM_NONLINEAR))
423 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
424 else
425 vma_prio_tree_insert(vma, &mapping->i_mmap);
426 flush_dcache_mmap_unlock(mapping);
427 }
428}
429
430static void
431__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
432 struct vm_area_struct *prev, struct rb_node **rb_link,
433 struct rb_node *rb_parent)
434{
435 __vma_link_list(mm, vma, prev, rb_parent);
436 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437}
438
439static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
440 struct vm_area_struct *prev, struct rb_node **rb_link,
441 struct rb_node *rb_parent)
442{
443 struct address_space *mapping = NULL;
444
445 if (vma->vm_file)
446 mapping = vma->vm_file->f_mapping;
447
Peter Zijlstra97a89412011-05-24 17:12:04 -0700448 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700449 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
451 __vma_link(mm, vma, prev, rb_link, rb_parent);
452 __vma_link_file(vma);
453
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700455 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456
457 mm->map_count++;
458 validate_mm(mm);
459}
460
461/*
462 * Helper for vma_adjust in the split_vma insert case:
463 * insert vm structure into list and rbtree and anon_vma,
464 * but it has already been inserted into prio_tree earlier.
465 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800466static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467{
ZhenwenXu48aae422009-01-06 14:40:21 -0800468 struct vm_area_struct *__vma, *prev;
469 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470
471 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200472 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 __vma_link(mm, vma, prev, rb_link, rb_parent);
474 mm->map_count++;
475}
476
477static inline void
478__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
479 struct vm_area_struct *prev)
480{
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700481 struct vm_area_struct *next = vma->vm_next;
482
483 prev->vm_next = next;
484 if (next)
485 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 rb_erase(&vma->vm_rb, &mm->mm_rb);
487 if (mm->mmap_cache == vma)
488 mm->mmap_cache = prev;
489}
490
491/*
492 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
493 * is already present in an i_mmap tree without adjusting the tree.
494 * The following helper function should be used when such adjustments
495 * are necessary. The "insert" vma (if any) is to be inserted
496 * before we drop the necessary locks.
497 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800498int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
500{
501 struct mm_struct *mm = vma->vm_mm;
502 struct vm_area_struct *next = vma->vm_next;
503 struct vm_area_struct *importer = NULL;
504 struct address_space *mapping = NULL;
505 struct prio_tree_root *root = NULL;
Rik van Riel012f1802010-08-09 17:18:40 -0700506 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 struct file *file = vma->vm_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 long adjust_next = 0;
509 int remove_next = 0;
510
511 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700512 struct vm_area_struct *exporter = NULL;
513
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 if (end >= next->vm_end) {
515 /*
516 * vma expands, overlapping all the next, and
517 * perhaps the one after too (mprotect case 6).
518 */
519again: remove_next = 1 + (end > next->vm_end);
520 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700521 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 importer = vma;
523 } else if (end > next->vm_start) {
524 /*
525 * vma expands, overlapping part of the next:
526 * mprotect case 5 shifting the boundary up.
527 */
528 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700529 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 importer = vma;
531 } else if (end < vma->vm_end) {
532 /*
533 * vma shrinks, and !insert tells it's not
534 * split_vma inserting another: so it must be
535 * mprotect case 4 shifting the boundary down.
536 */
537 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700538 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 importer = next;
540 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
Rik van Riel5beb4932010-03-05 13:42:07 -0800542 /*
543 * Easily overlooked: when mprotect shifts the boundary,
544 * make sure the expanding vma has anon_vma set if the
545 * shrinking vma had, to cover any anon pages imported.
546 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700547 if (exporter && exporter->anon_vma && !importer->anon_vma) {
548 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800549 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700550 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800551 }
552 }
553
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 if (file) {
555 mapping = file->f_mapping;
556 if (!(vma->vm_flags & VM_NONLINEAR))
557 root = &mapping->i_mmap;
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700558 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if (insert) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /*
561 * Put into prio_tree now, so instantiated pages
562 * are visible to arm/parisc __flush_dcache_page
563 * throughout; but we cannot insert into address
564 * space until vma start or end is updated.
565 */
566 __vma_link_file(insert);
567 }
568 }
569
Andrea Arcangeli94fcc582011-01-13 15:47:08 -0800570 vma_adjust_trans_huge(vma, start, end, adjust_next);
571
Rik van Riel012f1802010-08-09 17:18:40 -0700572 /*
573 * When changing only vma->vm_end, we don't really need anon_vma
574 * lock. This is a fairly rare case by itself, but the anon_vma
575 * lock may be shared between many sibling processes. Skipping
576 * the lock for brk adjustments makes a difference sometimes.
577 */
Shaohua Li5f70b962011-05-24 17:11:19 -0700578 if (vma->anon_vma && (importer || start != vma->vm_start)) {
Rik van Riel012f1802010-08-09 17:18:40 -0700579 anon_vma = vma->anon_vma;
580 anon_vma_lock(anon_vma);
581 }
582
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 if (root) {
584 flush_dcache_mmap_lock(mapping);
585 vma_prio_tree_remove(vma, root);
586 if (adjust_next)
587 vma_prio_tree_remove(next, root);
588 }
589
590 vma->vm_start = start;
591 vma->vm_end = end;
592 vma->vm_pgoff = pgoff;
593 if (adjust_next) {
594 next->vm_start += adjust_next << PAGE_SHIFT;
595 next->vm_pgoff += adjust_next;
596 }
597
598 if (root) {
599 if (adjust_next)
600 vma_prio_tree_insert(next, root);
601 vma_prio_tree_insert(vma, root);
602 flush_dcache_mmap_unlock(mapping);
603 }
604
605 if (remove_next) {
606 /*
607 * vma_merge has merged next into vma, and needs
608 * us to remove next before dropping the locks.
609 */
610 __vma_unlink(mm, next, vma);
611 if (file)
612 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 } else if (insert) {
614 /*
615 * split_vma has split insert from vma, and needs
616 * us to insert it before dropping the locks
617 * (it may either follow vma or precede it).
618 */
619 __insert_vm_struct(mm, insert);
620 }
621
Rik van Riel012f1802010-08-09 17:18:40 -0700622 if (anon_vma)
623 anon_vma_unlock(anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700625 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626
627 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700628 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700630 if (next->vm_flags & VM_EXECUTABLE)
631 removed_exe_file_vma(mm);
632 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800633 if (next->anon_vma)
634 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700636 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 kmem_cache_free(vm_area_cachep, next);
638 /*
639 * In mprotect's case 6 (see comments on vma_merge),
640 * we must remove another next too. It would clutter
641 * up the code too much to do both in one go.
642 */
643 if (remove_next == 2) {
644 next = vma->vm_next;
645 goto again;
646 }
647 }
648
649 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800650
651 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652}
653
654/*
655 * If the vma has a ->close operation then the driver probably needs to release
656 * per-vma resources, so we don't attempt to merge those.
657 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658static inline int is_mergeable_vma(struct vm_area_struct *vma,
659 struct file *file, unsigned long vm_flags)
660{
Hugh Dickins8314c4f2009-09-21 17:02:25 -0700661 /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */
662 if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 return 0;
664 if (vma->vm_file != file)
665 return 0;
666 if (vma->vm_ops && vma->vm_ops->close)
667 return 0;
668 return 1;
669}
670
671static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
Shaohua Li965f55d2011-05-24 17:11:20 -0700672 struct anon_vma *anon_vma2,
673 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674{
Shaohua Li965f55d2011-05-24 17:11:20 -0700675 /*
676 * The list_is_singular() test is to avoid merging VMA cloned from
677 * parents. This can improve scalability caused by anon_vma lock.
678 */
679 if ((!anon_vma1 || !anon_vma2) && (!vma ||
680 list_is_singular(&vma->anon_vma_chain)))
681 return 1;
682 return anon_vma1 == anon_vma2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683}
684
685/*
686 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
687 * in front of (at a lower virtual address and file offset than) the vma.
688 *
689 * We cannot merge two vmas if they have differently assigned (non-NULL)
690 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
691 *
692 * We don't check here for the merged mmap wrapping around the end of pagecache
693 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
694 * wrap, nor mmaps which cover the final page at index -1UL.
695 */
696static int
697can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
698 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
699{
700 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700701 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 if (vma->vm_pgoff == vm_pgoff)
703 return 1;
704 }
705 return 0;
706}
707
708/*
709 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
710 * beyond (at a higher virtual address and file offset than) the vma.
711 *
712 * We cannot merge two vmas if they have differently assigned (non-NULL)
713 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
714 */
715static int
716can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
717 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
718{
719 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700720 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 pgoff_t vm_pglen;
722 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
723 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
724 return 1;
725 }
726 return 0;
727}
728
729/*
730 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
731 * whether that can be merged with its predecessor or its successor.
732 * Or both (it neatly fills a hole).
733 *
734 * In most cases - when called for mmap, brk or mremap - [addr,end) is
735 * certain not to be mapped by the time vma_merge is called; but when
736 * called for mprotect, it is certain to be already mapped (either at
737 * an offset within prev, or at the start of next), and the flags of
738 * this area are about to be changed to vm_flags - and the no-change
739 * case has already been eliminated.
740 *
741 * The following mprotect cases have to be considered, where AAAA is
742 * the area passed down from mprotect_fixup, never extending beyond one
743 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
744 *
745 * AAAA AAAA AAAA AAAA
746 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
747 * cannot merge might become might become might become
748 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
749 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
750 * mremap move: PPPPNNNNNNNN 8
751 * AAAA
752 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
753 * might become case 1 below case 2 below case 3 below
754 *
755 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
756 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
757 */
758struct vm_area_struct *vma_merge(struct mm_struct *mm,
759 struct vm_area_struct *prev, unsigned long addr,
760 unsigned long end, unsigned long vm_flags,
761 struct anon_vma *anon_vma, struct file *file,
762 pgoff_t pgoff, struct mempolicy *policy)
763{
764 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
765 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800766 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
768 /*
769 * We later require that vma->vm_flags == vm_flags,
770 * so this tests vma->vm_flags & VM_SPECIAL, too.
771 */
772 if (vm_flags & VM_SPECIAL)
773 return NULL;
774
775 if (prev)
776 next = prev->vm_next;
777 else
778 next = mm->mmap;
779 area = next;
780 if (next && next->vm_end == end) /* cases 6, 7, 8 */
781 next = next->vm_next;
782
783 /*
784 * Can it merge with the predecessor?
785 */
786 if (prev && prev->vm_end == addr &&
787 mpol_equal(vma_policy(prev), policy) &&
788 can_vma_merge_after(prev, vm_flags,
789 anon_vma, file, pgoff)) {
790 /*
791 * OK, it can. Can we now merge in the successor as well?
792 */
793 if (next && end == next->vm_start &&
794 mpol_equal(policy, vma_policy(next)) &&
795 can_vma_merge_before(next, vm_flags,
796 anon_vma, file, pgoff+pglen) &&
797 is_mergeable_anon_vma(prev->anon_vma,
Shaohua Li965f55d2011-05-24 17:11:20 -0700798 next->anon_vma, NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800800 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 next->vm_end, prev->vm_pgoff, NULL);
802 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800803 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800805 if (err)
806 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -0800807 khugepaged_enter_vma_merge(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 return prev;
809 }
810
811 /*
812 * Can this new request be merged in front of next?
813 */
814 if (next && end == next->vm_start &&
815 mpol_equal(policy, vma_policy(next)) &&
816 can_vma_merge_before(next, vm_flags,
817 anon_vma, file, pgoff+pglen)) {
818 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800819 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 addr, prev->vm_pgoff, NULL);
821 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800822 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800824 if (err)
825 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -0800826 khugepaged_enter_vma_merge(area);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 return area;
828 }
829
830 return NULL;
831}
832
833/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700834 * Rough compatbility check to quickly see if it's even worth looking
835 * at sharing an anon_vma.
836 *
837 * They need to have the same vm_file, and the flags can only differ
838 * in things that mprotect may change.
839 *
840 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
841 * we can merge the two vma's. For example, we refuse to merge a vma if
842 * there is a vm_ops->close() function, because that indicates that the
843 * driver is doing some kind of reference counting. But that doesn't
844 * really matter for the anon_vma sharing case.
845 */
846static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
847{
848 return a->vm_end == b->vm_start &&
849 mpol_equal(vma_policy(a), vma_policy(b)) &&
850 a->vm_file == b->vm_file &&
851 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
852 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
853}
854
855/*
856 * Do some basic sanity checking to see if we can re-use the anon_vma
857 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
858 * the same as 'old', the other will be the new one that is trying
859 * to share the anon_vma.
860 *
861 * NOTE! This runs with mm_sem held for reading, so it is possible that
862 * the anon_vma of 'old' is concurrently in the process of being set up
863 * by another page fault trying to merge _that_. But that's ok: if it
864 * is being set up, that automatically means that it will be a singleton
865 * acceptable for merging, so we can do all of this optimistically. But
866 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
867 *
868 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
869 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
870 * is to return an anon_vma that is "complex" due to having gone through
871 * a fork).
872 *
873 * We also make sure that the two vma's are compatible (adjacent,
874 * and with the same memory policies). That's all stable, even with just
875 * a read lock on the mm_sem.
876 */
877static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
878{
879 if (anon_vma_compatible(a, b)) {
880 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
881
882 if (anon_vma && list_is_singular(&old->anon_vma_chain))
883 return anon_vma;
884 }
885 return NULL;
886}
887
888/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
890 * neighbouring vmas for a suitable anon_vma, before it goes off
891 * to allocate a new anon_vma. It checks because a repetitive
892 * sequence of mprotects and faults may otherwise lead to distinct
893 * anon_vmas being allocated, preventing vma merge in subsequent
894 * mprotect.
895 */
896struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
897{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700898 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900
901 near = vma->vm_next;
902 if (!near)
903 goto try_prev;
904
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700905 anon_vma = reusable_anon_vma(near, vma, near);
906 if (anon_vma)
907 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908try_prev:
909 /*
910 * It is potentially slow to have to call find_vma_prev here.
911 * But it's only on the first write fault on the vma, not
912 * every time, and we could devise a way to avoid it later
913 * (e.g. stash info in next's anon_vma_node when assigning
914 * an anon_vma, or when trying vma_merge). Another time.
915 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200916 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 if (!near)
918 goto none;
919
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -0700920 anon_vma = reusable_anon_vma(near, near, vma);
921 if (anon_vma)
922 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923none:
924 /*
925 * There's no absolute need to look only at touching neighbours:
926 * we could search further afield for "compatible" anon_vmas.
927 * But it would probably just be a waste of time searching,
928 * or lead to too many vmas hanging off the same anon_vma.
929 * We're trying to allow mprotect remerging later on,
930 * not trying to minimize memory used for anon_vmas.
931 */
932 return NULL;
933}
934
935#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700936void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 struct file *file, long pages)
938{
939 const unsigned long stack_flags
940 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
941
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 if (file) {
943 mm->shared_vm += pages;
944 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
945 mm->exec_vm += pages;
946 } else if (flags & stack_flags)
947 mm->stack_vm += pages;
948 if (flags & (VM_RESERVED|VM_IO))
949 mm->reserved_vm += pages;
950}
951#endif /* CONFIG_PROC_FS */
952
953/*
Jianjun Kong27f5de72009-09-17 19:26:26 -0700954 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 */
956
ZhenwenXu48aae422009-01-06 14:40:21 -0800957unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 unsigned long len, unsigned long prot,
959 unsigned long flags, unsigned long pgoff)
960{
961 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 struct inode *inode;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900963 vm_flags_t vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 int error;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700965 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 /*
968 * Does the application expect PROT_READ to imply PROT_EXEC?
969 *
970 * (the exception is when the underlying filesystem is noexec
971 * mounted, in which case we dont add PROT_EXEC.)
972 */
973 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800974 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 prot |= PROT_EXEC;
976
977 if (!len)
978 return -EINVAL;
979
Eric Paris7cd94142007-11-26 18:47:40 -0500980 if (!(flags & MAP_FIXED))
981 addr = round_hint_to_min(addr);
982
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 /* Careful about overflows.. */
984 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -0500985 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 return -ENOMEM;
987
988 /* offset overflow? */
989 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
990 return -EOVERFLOW;
991
992 /* Too many mappings? */
993 if (mm->map_count > sysctl_max_map_count)
994 return -ENOMEM;
995
996 /* Obtain the address to map to. we verify (or select) it and ensure
997 * that it represents a valid section of the address space.
998 */
999 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1000 if (addr & ~PAGE_MASK)
1001 return addr;
1002
1003 /* Do simple checking here so the lower-level routines won't have
1004 * to. we assume access permissions have been handled by the open
1005 * of the memory object, so we don't do any here.
1006 */
1007 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1008 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1009
Huang Shijiecdf7b342009-09-21 17:03:36 -07001010 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 if (!can_do_mlock())
1012 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 /* mlock MCL_FUTURE? */
1015 if (vm_flags & VM_LOCKED) {
1016 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001017 locked = len >> PAGE_SHIFT;
1018 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001019 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001020 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1022 return -EAGAIN;
1023 }
1024
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001025 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026
1027 if (file) {
1028 switch (flags & MAP_TYPE) {
1029 case MAP_SHARED:
1030 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1031 return -EACCES;
1032
1033 /*
1034 * Make sure we don't allow writing to an append-only
1035 * file..
1036 */
1037 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1038 return -EACCES;
1039
1040 /*
1041 * Make sure there are no mandatory locks on the file.
1042 */
1043 if (locks_verify_locked(inode))
1044 return -EAGAIN;
1045
1046 vm_flags |= VM_SHARED | VM_MAYSHARE;
1047 if (!(file->f_mode & FMODE_WRITE))
1048 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1049
1050 /* fall through */
1051 case MAP_PRIVATE:
1052 if (!(file->f_mode & FMODE_READ))
1053 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001054 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001055 if (vm_flags & VM_EXEC)
1056 return -EPERM;
1057 vm_flags &= ~VM_MAYEXEC;
1058 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001059
1060 if (!file->f_op || !file->f_op->mmap)
1061 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062 break;
1063
1064 default:
1065 return -EINVAL;
1066 }
1067 } else {
1068 switch (flags & MAP_TYPE) {
1069 case MAP_SHARED:
Tejun Heoce363942008-09-03 16:09:47 +02001070 /*
1071 * Ignore pgoff.
1072 */
1073 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 vm_flags |= VM_SHARED | VM_MAYSHARE;
1075 break;
1076 case MAP_PRIVATE:
1077 /*
1078 * Set pgoff according to addr for anon_vma.
1079 */
1080 pgoff = addr >> PAGE_SHIFT;
1081 break;
1082 default:
1083 return -EINVAL;
1084 }
1085 }
1086
Eric Parised032182007-06-28 15:55:21 -04001087 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 if (error)
1089 return error;
Eric Parised032182007-06-28 15:55:21 -04001090
Mel Gorman5a6fe122009-02-10 14:02:27 +00001091 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001092}
1093EXPORT_SYMBOL(do_mmap_pgoff);
1094
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001095SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1096 unsigned long, prot, unsigned long, flags,
1097 unsigned long, fd, unsigned long, pgoff)
1098{
1099 struct file *file = NULL;
1100 unsigned long retval = -EBADF;
1101
1102 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001103 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001104 if (unlikely(flags & MAP_HUGETLB))
1105 return -EINVAL;
1106 file = fget(fd);
1107 if (!file)
1108 goto out;
1109 } else if (flags & MAP_HUGETLB) {
1110 struct user_struct *user = NULL;
1111 /*
1112 * VM_NORESERVE is used because the reservations will be
1113 * taken when vm_ops->mmap() is called
1114 * A dummy user value is used because we are not locking
1115 * memory so no accounting is necessary
1116 */
1117 len = ALIGN(len, huge_page_size(&default_hstate));
1118 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
1119 &user, HUGETLB_ANONHUGE_INODE);
1120 if (IS_ERR(file))
1121 return PTR_ERR(file);
1122 }
1123
1124 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1125
1126 down_write(&current->mm->mmap_sem);
1127 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1128 up_write(&current->mm->mmap_sem);
1129
1130 if (file)
1131 fput(file);
1132out:
1133 return retval;
1134}
1135
Christoph Hellwiga4679372010-03-10 15:21:15 -08001136#ifdef __ARCH_WANT_SYS_OLD_MMAP
1137struct mmap_arg_struct {
1138 unsigned long addr;
1139 unsigned long len;
1140 unsigned long prot;
1141 unsigned long flags;
1142 unsigned long fd;
1143 unsigned long offset;
1144};
1145
1146SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1147{
1148 struct mmap_arg_struct a;
1149
1150 if (copy_from_user(&a, arg, sizeof(a)))
1151 return -EFAULT;
1152 if (a.offset & ~PAGE_MASK)
1153 return -EINVAL;
1154
1155 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1156 a.offset >> PAGE_SHIFT);
1157}
1158#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1159
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001160/*
1161 * Some shared mappigns will want the pages marked read-only
1162 * to track write events. If so, we'll downgrade vm_page_prot
1163 * to the private version (using protection_map[] without the
1164 * VM_SHARED bit).
1165 */
1166int vma_wants_writenotify(struct vm_area_struct *vma)
1167{
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001168 vm_flags_t vm_flags = vma->vm_flags;
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001169
1170 /* If it was private or non-writable, the write bit is already clear */
1171 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1172 return 0;
1173
1174 /* The backer wishes to know when pages are first written to? */
1175 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1176 return 1;
1177
1178 /* The open routine did something to the protections already? */
1179 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001180 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001181 return 0;
1182
1183 /* Specialty mapping? */
1184 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1185 return 0;
1186
1187 /* Can the mapping track the dirty pages? */
1188 return vma->vm_file && vma->vm_file->f_mapping &&
1189 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1190}
1191
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001192/*
1193 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001194 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001195 */
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001196static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001197{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001198 /*
1199 * hugetlb has its own accounting separate from the core VM
1200 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1201 */
1202 if (file && is_file_hugepages(file))
1203 return 0;
1204
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001205 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1206}
1207
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001208unsigned long mmap_region(struct file *file, unsigned long addr,
1209 unsigned long len, unsigned long flags,
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001210 vm_flags_t vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001211{
1212 struct mm_struct *mm = current->mm;
1213 struct vm_area_struct *vma, *prev;
1214 int correct_wcount = 0;
1215 int error;
1216 struct rb_node **rb_link, *rb_parent;
1217 unsigned long charged = 0;
1218 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1219
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 /* Clear old maps */
1221 error = -ENOMEM;
1222munmap_back:
1223 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1224 if (vma && vma->vm_start < addr + len) {
1225 if (do_munmap(mm, addr, len))
1226 return -ENOMEM;
1227 goto munmap_back;
1228 }
1229
1230 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001231 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 return -ENOMEM;
1233
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001234 /*
1235 * Set 'VM_NORESERVE' if we should not account for the
Mel Gorman5a6fe122009-02-10 14:02:27 +00001236 * memory use of this mapping.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001237 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001238 if ((flags & MAP_NORESERVE)) {
1239 /* We honor MAP_NORESERVE if allowed to overcommit */
1240 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1241 vm_flags |= VM_NORESERVE;
1242
1243 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1244 if (file && is_file_hugepages(file))
1245 vm_flags |= VM_NORESERVE;
1246 }
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001247
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001248 /*
1249 * Private writable mapping: check memory availability
1250 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001251 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001252 charged = len >> PAGE_SHIFT;
1253 if (security_vm_enough_memory(charged))
1254 return -ENOMEM;
1255 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 }
1257
1258 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001259 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001261 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1262 if (vma)
1263 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264
1265 /*
1266 * Determine the object being mapped and call the appropriate
1267 * specific mapper. the address has already been validated, but
1268 * not unmapped, but the maps are removed from the list.
1269 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001270 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 if (!vma) {
1272 error = -ENOMEM;
1273 goto unacct_error;
1274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
1276 vma->vm_mm = mm;
1277 vma->vm_start = addr;
1278 vma->vm_end = addr + len;
1279 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001280 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001282 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283
1284 if (file) {
1285 error = -EINVAL;
1286 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1287 goto free_vma;
1288 if (vm_flags & VM_DENYWRITE) {
1289 error = deny_write_access(file);
1290 if (error)
1291 goto free_vma;
1292 correct_wcount = 1;
1293 }
1294 vma->vm_file = file;
1295 get_file(file);
1296 error = file->f_op->mmap(file, vma);
1297 if (error)
1298 goto unmap_and_free_vma;
Matt Helsley925d1c42008-04-29 01:01:36 -07001299 if (vm_flags & VM_EXECUTABLE)
1300 added_exe_file_vma(mm);
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001301
1302 /* Can addr have changed??
1303 *
1304 * Answer: Yes, several device drivers can do it in their
1305 * f_op->mmap method. -DaveM
1306 */
1307 addr = vma->vm_start;
1308 pgoff = vma->vm_pgoff;
1309 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 } else if (vm_flags & VM_SHARED) {
1311 error = shmem_zero_setup(vma);
1312 if (error)
1313 goto free_vma;
1314 }
1315
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001316 if (vma_wants_writenotify(vma)) {
1317 pgprot_t pprot = vma->vm_page_prot;
1318
1319 /* Can vma->vm_page_prot have changed??
1320 *
1321 * Answer: Yes, drivers may have changed it in their
1322 * f_op->mmap method.
1323 *
1324 * Ensures that vmas marked as uncached stay that way.
1325 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001326 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001327 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1328 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1329 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001330
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001331 vma_link(mm, vma, prev, rb_link, rb_parent);
1332 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001333
1334 /* Once vma denies write, undo our temporary denial count */
1335 if (correct_wcount)
1336 atomic_inc(&inode->i_writecount);
1337out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001338 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001339
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001341 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 if (vm_flags & VM_LOCKED) {
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001343 if (!mlock_vma_pages_range(vma, addr, addr + len))
1344 mm->locked_vm += (len >> PAGE_SHIFT);
Rik van Rielba470de2008-10-18 20:26:50 -07001345 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
Nick Piggin54cb8822007-07-19 01:46:59 -07001346 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 return addr;
1348
1349unmap_and_free_vma:
1350 if (correct_wcount)
1351 atomic_inc(&inode->i_writecount);
1352 vma->vm_file = NULL;
1353 fput(file);
1354
1355 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001356 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1357 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358free_vma:
1359 kmem_cache_free(vm_area_cachep, vma);
1360unacct_error:
1361 if (charged)
1362 vm_unacct_memory(charged);
1363 return error;
1364}
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366/* Get an address range which is currently unmapped.
1367 * For shmat() with addr=0.
1368 *
1369 * Ugly calling convention alert:
1370 * Return value with the low bits set means error value,
1371 * ie
1372 * if (ret & ~PAGE_MASK)
1373 * error = ret;
1374 *
1375 * This function "knows" that -ENOMEM has the bits set.
1376 */
1377#ifndef HAVE_ARCH_UNMAPPED_AREA
1378unsigned long
1379arch_get_unmapped_area(struct file *filp, unsigned long addr,
1380 unsigned long len, unsigned long pgoff, unsigned long flags)
1381{
1382 struct mm_struct *mm = current->mm;
1383 struct vm_area_struct *vma;
1384 unsigned long start_addr;
1385
1386 if (len > TASK_SIZE)
1387 return -ENOMEM;
1388
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001389 if (flags & MAP_FIXED)
1390 return addr;
1391
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 if (addr) {
1393 addr = PAGE_ALIGN(addr);
1394 vma = find_vma(mm, addr);
1395 if (TASK_SIZE - len >= addr &&
1396 (!vma || addr + len <= vma->vm_start))
1397 return addr;
1398 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001399 if (len > mm->cached_hole_size) {
1400 start_addr = addr = mm->free_area_cache;
1401 } else {
1402 start_addr = addr = TASK_UNMAPPED_BASE;
1403 mm->cached_hole_size = 0;
1404 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405
1406full_search:
1407 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1408 /* At this point: (!vma || addr < vma->vm_end). */
1409 if (TASK_SIZE - len < addr) {
1410 /*
1411 * Start a new search - just in case we missed
1412 * some holes.
1413 */
1414 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001415 addr = TASK_UNMAPPED_BASE;
1416 start_addr = addr;
1417 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 goto full_search;
1419 }
1420 return -ENOMEM;
1421 }
1422 if (!vma || addr + len <= vma->vm_start) {
1423 /*
1424 * Remember the place where we stopped the search:
1425 */
1426 mm->free_area_cache = addr + len;
1427 return addr;
1428 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001429 if (addr + mm->cached_hole_size < vma->vm_start)
1430 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 addr = vma->vm_end;
1432 }
1433}
1434#endif
1435
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001436void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437{
1438 /*
1439 * Is this a new hole at the lowest possible address?
1440 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001441 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1442 mm->free_area_cache = addr;
1443 mm->cached_hole_size = ~0UL;
1444 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445}
1446
1447/*
1448 * This mmap-allocator allocates new areas top-down from below the
1449 * stack's low limit (the base):
1450 */
1451#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1452unsigned long
1453arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1454 const unsigned long len, const unsigned long pgoff,
1455 const unsigned long flags)
1456{
1457 struct vm_area_struct *vma;
1458 struct mm_struct *mm = current->mm;
1459 unsigned long addr = addr0;
1460
1461 /* requested length too big for entire address space */
1462 if (len > TASK_SIZE)
1463 return -ENOMEM;
1464
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001465 if (flags & MAP_FIXED)
1466 return addr;
1467
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 /* requesting a specific address */
1469 if (addr) {
1470 addr = PAGE_ALIGN(addr);
1471 vma = find_vma(mm, addr);
1472 if (TASK_SIZE - len >= addr &&
1473 (!vma || addr + len <= vma->vm_start))
1474 return addr;
1475 }
1476
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001477 /* check if free_area_cache is useful for us */
1478 if (len <= mm->cached_hole_size) {
1479 mm->cached_hole_size = 0;
1480 mm->free_area_cache = mm->mmap_base;
1481 }
1482
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 /* either no address requested or can't fit in requested address hole */
1484 addr = mm->free_area_cache;
1485
1486 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001487 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 vma = find_vma(mm, addr-len);
1489 if (!vma || addr <= vma->vm_start)
1490 /* remember the address as a hint for next time */
1491 return (mm->free_area_cache = addr-len);
1492 }
1493
Chris Wright73219d12005-06-21 17:14:52 -07001494 if (mm->mmap_base < len)
1495 goto bottomup;
1496
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 addr = mm->mmap_base-len;
1498
1499 do {
1500 /*
1501 * Lookup failure means no vma is above this address,
1502 * else if new region fits below vma->vm_start,
1503 * return with success:
1504 */
1505 vma = find_vma(mm, addr);
1506 if (!vma || addr+len <= vma->vm_start)
1507 /* remember the address as a hint for next time */
1508 return (mm->free_area_cache = addr);
1509
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001510 /* remember the largest hole we saw so far */
1511 if (addr + mm->cached_hole_size < vma->vm_start)
1512 mm->cached_hole_size = vma->vm_start - addr;
1513
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 /* try just below the current vma->vm_start */
1515 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001516 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517
Chris Wright73219d12005-06-21 17:14:52 -07001518bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 /*
1520 * A failed mmap() very likely causes application failure,
1521 * so fall back to the bottom-up function here. This scenario
1522 * can happen with large stack limits and large mmap()
1523 * allocations.
1524 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001525 mm->cached_hole_size = ~0UL;
1526 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1528 /*
1529 * Restore the topdown base:
1530 */
1531 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001532 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533
1534 return addr;
1535}
1536#endif
1537
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001538void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539{
1540 /*
1541 * Is this a new hole at the highest possible address?
1542 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001543 if (addr > mm->free_area_cache)
1544 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545
1546 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001547 if (mm->free_area_cache > mm->mmap_base)
1548 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549}
1550
1551unsigned long
1552get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1553 unsigned long pgoff, unsigned long flags)
1554{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001555 unsigned long (*get_area)(struct file *, unsigned long,
1556 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
Al Viro9206de92009-12-03 15:23:11 -05001558 unsigned long error = arch_mmap_check(addr, len, flags);
1559 if (error)
1560 return error;
1561
1562 /* Careful about overflows.. */
1563 if (len > TASK_SIZE)
1564 return -ENOMEM;
1565
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001566 get_area = current->mm->get_unmapped_area;
1567 if (file && file->f_op && file->f_op->get_unmapped_area)
1568 get_area = file->f_op->get_unmapped_area;
1569 addr = get_area(file, addr, len, pgoff, flags);
1570 if (IS_ERR_VALUE(addr))
1571 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001573 if (addr > TASK_SIZE - len)
1574 return -ENOMEM;
1575 if (addr & ~PAGE_MASK)
1576 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001577
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -08001578 return arch_rebalance_pgtables(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579}
1580
1581EXPORT_SYMBOL(get_unmapped_area);
1582
1583/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001584struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585{
1586 struct vm_area_struct *vma = NULL;
1587
1588 if (mm) {
1589 /* Check the cache first. */
1590 /* (Cache hit rate is typically around 35%.) */
1591 vma = mm->mmap_cache;
1592 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1593 struct rb_node * rb_node;
1594
1595 rb_node = mm->mm_rb.rb_node;
1596 vma = NULL;
1597
1598 while (rb_node) {
1599 struct vm_area_struct * vma_tmp;
1600
1601 vma_tmp = rb_entry(rb_node,
1602 struct vm_area_struct, vm_rb);
1603
1604 if (vma_tmp->vm_end > addr) {
1605 vma = vma_tmp;
1606 if (vma_tmp->vm_start <= addr)
1607 break;
1608 rb_node = rb_node->rb_left;
1609 } else
1610 rb_node = rb_node->rb_right;
1611 }
1612 if (vma)
1613 mm->mmap_cache = vma;
1614 }
1615 }
1616 return vma;
1617}
1618
1619EXPORT_SYMBOL(find_vma);
1620
1621/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1622struct vm_area_struct *
1623find_vma_prev(struct mm_struct *mm, unsigned long addr,
1624 struct vm_area_struct **pprev)
1625{
1626 struct vm_area_struct *vma = NULL, *prev = NULL;
ZhenwenXu48aae422009-01-06 14:40:21 -08001627 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628 if (!mm)
1629 goto out;
1630
1631 /* Guard against addr being lower than the first VMA */
1632 vma = mm->mmap;
1633
1634 /* Go through the RB tree quickly. */
1635 rb_node = mm->mm_rb.rb_node;
1636
1637 while (rb_node) {
1638 struct vm_area_struct *vma_tmp;
1639 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1640
1641 if (addr < vma_tmp->vm_end) {
1642 rb_node = rb_node->rb_left;
1643 } else {
1644 prev = vma_tmp;
1645 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1646 break;
1647 rb_node = rb_node->rb_right;
1648 }
1649 }
1650
1651out:
1652 *pprev = prev;
1653 return prev ? prev->vm_next : vma;
1654}
1655
1656/*
1657 * Verify that the stack growth is acceptable and
1658 * update accounting. This is shared with both the
1659 * grow-up and grow-down cases.
1660 */
ZhenwenXu48aae422009-01-06 14:40:21 -08001661static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662{
1663 struct mm_struct *mm = vma->vm_mm;
1664 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001665 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666
1667 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001668 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 return -ENOMEM;
1670
1671 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08001672 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 return -ENOMEM;
1674
1675 /* mlock limit tests */
1676 if (vma->vm_flags & VM_LOCKED) {
1677 unsigned long locked;
1678 unsigned long limit;
1679 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001680 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
1681 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682 if (locked > limit && !capable(CAP_IPC_LOCK))
1683 return -ENOMEM;
1684 }
1685
Adam Litke0d59a012007-01-30 14:35:39 -08001686 /* Check to ensure the stack will not grow into a hugetlb-only region */
1687 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1688 vma->vm_end - size;
1689 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1690 return -EFAULT;
1691
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 /*
1693 * Overcommit.. This must be the final test, as it will
1694 * update security statistics.
1695 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01001696 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 return -ENOMEM;
1698
1699 /* Ok, everything looks good - let it rip */
1700 mm->total_vm += grow;
1701 if (vma->vm_flags & VM_LOCKED)
1702 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001703 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704 return 0;
1705}
1706
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001707#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001709 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1710 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001712int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713{
1714 int error;
1715
1716 if (!(vma->vm_flags & VM_GROWSUP))
1717 return -EFAULT;
1718
1719 /*
1720 * We must make sure the anon_vma is allocated
1721 * so that the anon_vma locking is not a noop.
1722 */
1723 if (unlikely(anon_vma_prepare(vma)))
1724 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07001725 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726
1727 /*
1728 * vma->vm_start/vm_end cannot change under us because the caller
1729 * is required to hold the mmap_sem in read mode. We need the
1730 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001731 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 */
Helge Deller06b32f32006-12-19 19:28:33 +01001733 if (address < PAGE_ALIGN(address+4))
1734 address = PAGE_ALIGN(address+4);
1735 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07001736 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01001737 return -ENOMEM;
1738 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739 error = 0;
1740
1741 /* Somebody else might have raced and expanded it already */
1742 if (address > vma->vm_end) {
1743 unsigned long size, grow;
1744
1745 size = address - vma->vm_start;
1746 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1747
Hugh Dickins42c36f62011-05-09 17:44:42 -07001748 error = -ENOMEM;
1749 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
1750 error = acct_stack_growth(vma, size, grow);
1751 if (!error) {
1752 vma->vm_end = address;
1753 perf_event_mmap(vma);
1754 }
Eric B Munson3af9e852010-05-18 15:30:49 +01001755 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001757 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001758 khugepaged_enter_vma_merge(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 return error;
1760}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001761#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1762
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763/*
1764 * vma is the first one with address < vma->vm_start. Have to extend vma.
1765 */
Michal Hockod05f3162011-05-24 17:11:44 -07001766int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001767 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768{
1769 int error;
1770
1771 /*
1772 * We must make sure the anon_vma is allocated
1773 * so that the anon_vma locking is not a noop.
1774 */
1775 if (unlikely(anon_vma_prepare(vma)))
1776 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001777
1778 address &= PAGE_MASK;
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01001779 error = security_file_mmap(NULL, 0, 0, 0, address, 1);
Eric Paris88694772007-11-26 18:47:26 -05001780 if (error)
1781 return error;
1782
Rik van Rielbb4a3402010-08-09 17:18:37 -07001783 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784
1785 /*
1786 * vma->vm_start/vm_end cannot change under us because the caller
1787 * is required to hold the mmap_sem in read mode. We need the
1788 * anon_vma lock to serialize against concurrent expand_stacks.
1789 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790
1791 /* Somebody else might have raced and expanded it already */
1792 if (address < vma->vm_start) {
1793 unsigned long size, grow;
1794
1795 size = vma->vm_end - address;
1796 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1797
Linus Torvaldsa626ca62011-04-13 08:07:28 -07001798 error = -ENOMEM;
1799 if (grow <= vma->vm_pgoff) {
1800 error = acct_stack_growth(vma, size, grow);
1801 if (!error) {
1802 vma->vm_start = address;
1803 vma->vm_pgoff -= grow;
1804 perf_event_mmap(vma);
1805 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806 }
1807 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07001808 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001809 khugepaged_enter_vma_merge(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 return error;
1811}
1812
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001813#ifdef CONFIG_STACK_GROWSUP
1814int expand_stack(struct vm_area_struct *vma, unsigned long address)
1815{
1816 return expand_upwards(vma, address);
1817}
1818
1819struct vm_area_struct *
1820find_extend_vma(struct mm_struct *mm, unsigned long addr)
1821{
1822 struct vm_area_struct *vma, *prev;
1823
1824 addr &= PAGE_MASK;
1825 vma = find_vma_prev(mm, addr, &prev);
1826 if (vma && (vma->vm_start <= addr))
1827 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01001828 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001829 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001830 if (prev->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001831 mlock_vma_pages_range(prev, addr, prev->vm_end);
Rik van Rielba470de2008-10-18 20:26:50 -07001832 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001833 return prev;
1834}
1835#else
1836int expand_stack(struct vm_area_struct *vma, unsigned long address)
1837{
1838 return expand_downwards(vma, address);
1839}
1840
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841struct vm_area_struct *
1842find_extend_vma(struct mm_struct * mm, unsigned long addr)
1843{
1844 struct vm_area_struct * vma;
1845 unsigned long start;
1846
1847 addr &= PAGE_MASK;
1848 vma = find_vma(mm,addr);
1849 if (!vma)
1850 return NULL;
1851 if (vma->vm_start <= addr)
1852 return vma;
1853 if (!(vma->vm_flags & VM_GROWSDOWN))
1854 return NULL;
1855 start = vma->vm_start;
1856 if (expand_stack(vma, addr))
1857 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07001858 if (vma->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08001859 mlock_vma_pages_range(vma, addr, start);
Rik van Rielba470de2008-10-18 20:26:50 -07001860 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 return vma;
1862}
1863#endif
1864
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001866 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001868 *
1869 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001871static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001873 /* Update high watermark before we lower total_vm */
1874 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001876 long nrpages = vma_pages(vma);
1877
1878 mm->total_vm -= nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001879 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001880 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001881 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 validate_mm(mm);
1883}
1884
1885/*
1886 * Get rid of page table information in the indicated region.
1887 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001888 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889 */
1890static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001891 struct vm_area_struct *vma, struct vm_area_struct *prev,
1892 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001894 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07001895 struct mmu_gather tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 unsigned long nr_accounted = 0;
1897
1898 lru_add_drain();
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07001899 tlb_gather_mmu(&tlb, mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001900 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001901 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 vm_unacct_memory(nr_accounted);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07001903 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
1904 next ? next->vm_start : 0);
1905 tlb_finish_mmu(&tlb, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906}
1907
1908/*
1909 * Create a list of vma's touched by the unmap, removing them from the mm's
1910 * vma list as we go..
1911 */
1912static void
1913detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1914 struct vm_area_struct *prev, unsigned long end)
1915{
1916 struct vm_area_struct **insertion_point;
1917 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001918 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919
1920 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001921 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 do {
1923 rb_erase(&vma->vm_rb, &mm->mm_rb);
1924 mm->map_count--;
1925 tail_vma = vma;
1926 vma = vma->vm_next;
1927 } while (vma && vma->vm_start < end);
1928 *insertion_point = vma;
Linus Torvalds297c5ee2010-08-20 16:24:55 -07001929 if (vma)
1930 vma->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001932 if (mm->unmap_area == arch_unmap_area)
1933 addr = prev ? prev->vm_end : mm->mmap_base;
1934 else
1935 addr = vma ? vma->vm_start : mm->mmap_base;
1936 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 mm->mmap_cache = NULL; /* Kill the cache. */
1938}
1939
1940/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001941 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
1942 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08001944static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 unsigned long addr, int new_below)
1946{
1947 struct mempolicy *pol;
1948 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08001949 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950
Andi Kleena5516432008-07-23 21:27:41 -07001951 if (is_vm_hugetlb_page(vma) && (addr &
1952 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 return -EINVAL;
1954
Christoph Lametere94b1762006-12-06 20:33:17 -08001955 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08001957 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958
1959 /* most fields are the same, copy all, and then fixup */
1960 *new = *vma;
1961
Rik van Riel5beb4932010-03-05 13:42:07 -08001962 INIT_LIST_HEAD(&new->anon_vma_chain);
1963
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 if (new_below)
1965 new->vm_end = addr;
1966 else {
1967 new->vm_start = addr;
1968 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1969 }
1970
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07001971 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 if (IS_ERR(pol)) {
Rik van Riel5beb4932010-03-05 13:42:07 -08001973 err = PTR_ERR(pol);
1974 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 }
1976 vma_set_policy(new, pol);
1977
Rik van Riel5beb4932010-03-05 13:42:07 -08001978 if (anon_vma_clone(new, vma))
1979 goto out_free_mpol;
1980
Matt Helsley925d1c42008-04-29 01:01:36 -07001981 if (new->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982 get_file(new->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001983 if (vma->vm_flags & VM_EXECUTABLE)
1984 added_exe_file_vma(mm);
1985 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986
1987 if (new->vm_ops && new->vm_ops->open)
1988 new->vm_ops->open(new);
1989
1990 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08001991 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1993 else
Rik van Riel5beb4932010-03-05 13:42:07 -08001994 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001995
Rik van Riel5beb4932010-03-05 13:42:07 -08001996 /* Success. */
1997 if (!err)
1998 return 0;
1999
2000 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002001 if (new->vm_ops && new->vm_ops->close)
2002 new->vm_ops->close(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002003 if (new->vm_file) {
2004 if (vma->vm_flags & VM_EXECUTABLE)
2005 removed_exe_file_vma(mm);
2006 fput(new->vm_file);
2007 }
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002008 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002009 out_free_mpol:
2010 mpol_put(pol);
2011 out_free_vma:
2012 kmem_cache_free(vm_area_cachep, new);
2013 out_err:
2014 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015}
2016
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002017/*
2018 * Split a vma into two pieces at address 'addr', a new vma is allocated
2019 * either for the first part or the tail.
2020 */
2021int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2022 unsigned long addr, int new_below)
2023{
2024 if (mm->map_count >= sysctl_max_map_count)
2025 return -ENOMEM;
2026
2027 return __split_vma(mm, vma, addr, new_below);
2028}
2029
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030/* Munmap is split into 2 main parts -- this part which finds
2031 * what needs doing, and the areas themselves, which do the
2032 * work. This now handles partial unmappings.
2033 * Jeremy Fitzhardinge <jeremy@goop.org>
2034 */
2035int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2036{
2037 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002038 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039
2040 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2041 return -EINVAL;
2042
2043 if ((len = PAGE_ALIGN(len)) == 0)
2044 return -EINVAL;
2045
2046 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07002047 vma = find_vma_prev(mm, start, &prev);
2048 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07002050 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002051
2052 /* if it doesn't overlap, we have nothing.. */
2053 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002054 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 return 0;
2056
2057 /*
2058 * If we need to split any vma, do it now to save pain later.
2059 *
2060 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2061 * unmapped vm_area_struct will remain in use: so lower split_vma
2062 * places tmp vma above, and higher split_vma places tmp vma below.
2063 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002064 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002065 int error;
2066
2067 /*
2068 * Make sure that map_count on return from munmap() will
2069 * not exceed its limit; but let map_count go just above
2070 * its limit temporarily, to help free resources as expected.
2071 */
2072 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2073 return -ENOMEM;
2074
2075 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076 if (error)
2077 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002078 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079 }
2080
2081 /* Does it split the last one? */
2082 last = find_vma(mm, end);
2083 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002084 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085 if (error)
2086 return error;
2087 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002088 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089
2090 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002091 * unlock any mlock()ed ranges before detaching vmas
2092 */
2093 if (mm->locked_vm) {
2094 struct vm_area_struct *tmp = vma;
2095 while (tmp && tmp->vm_start < end) {
2096 if (tmp->vm_flags & VM_LOCKED) {
2097 mm->locked_vm -= vma_pages(tmp);
2098 munlock_vma_pages_all(tmp);
2099 }
2100 tmp = tmp->vm_next;
2101 }
2102 }
2103
2104 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105 * Remove the vma's, and unmap the actual pages
2106 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002107 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2108 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109
2110 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002111 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112
2113 return 0;
2114}
2115
2116EXPORT_SYMBOL(do_munmap);
2117
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002118SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002119{
2120 int ret;
2121 struct mm_struct *mm = current->mm;
2122
2123 profile_munmap(addr);
2124
2125 down_write(&mm->mmap_sem);
2126 ret = do_munmap(mm, addr, len);
2127 up_write(&mm->mmap_sem);
2128 return ret;
2129}
2130
2131static inline void verify_mm_writelocked(struct mm_struct *mm)
2132{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002133#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2135 WARN_ON(1);
2136 up_read(&mm->mmap_sem);
2137 }
2138#endif
2139}
2140
2141/*
2142 * this is really a simplified "do_mmap". it only handles
2143 * anonymous maps. eventually we may be able to do some
2144 * brk-specific accounting here.
2145 */
2146unsigned long do_brk(unsigned long addr, unsigned long len)
2147{
2148 struct mm_struct * mm = current->mm;
2149 struct vm_area_struct * vma, * prev;
2150 unsigned long flags;
2151 struct rb_node ** rb_link, * rb_parent;
2152 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002153 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002154
2155 len = PAGE_ALIGN(len);
2156 if (!len)
2157 return addr;
2158
Richard Knutsson88c3f7a2007-12-08 12:02:48 +01002159 error = security_file_mmap(NULL, 0, 0, 0, addr, 1);
Eric Paris5a211a52007-12-04 11:06:55 -05002160 if (error)
2161 return error;
2162
Kirill Korotaev3a459752006-09-07 14:17:04 +04002163 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2164
Al Viro2c6a10162009-12-03 19:40:46 -05002165 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2166 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002167 return error;
2168
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 /*
2170 * mlock MCL_FUTURE?
2171 */
2172 if (mm->def_flags & VM_LOCKED) {
2173 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002174 locked = len >> PAGE_SHIFT;
2175 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002176 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002177 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2179 return -EAGAIN;
2180 }
2181
2182 /*
2183 * mm->mmap_sem is required to protect against another thread
2184 * changing the mappings in case we sleep.
2185 */
2186 verify_mm_writelocked(mm);
2187
2188 /*
2189 * Clear old maps. this also does some error checking for us
2190 */
2191 munmap_back:
2192 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2193 if (vma && vma->vm_start < addr + len) {
2194 if (do_munmap(mm, addr, len))
2195 return -ENOMEM;
2196 goto munmap_back;
2197 }
2198
2199 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002200 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201 return -ENOMEM;
2202
2203 if (mm->map_count > sysctl_max_map_count)
2204 return -ENOMEM;
2205
2206 if (security_vm_enough_memory(len >> PAGE_SHIFT))
2207 return -ENOMEM;
2208
Linus Torvalds1da177e2005-04-16 15:20:36 -07002209 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002210 vma = vma_merge(mm, prev, addr, addr + len, flags,
2211 NULL, NULL, pgoff, NULL);
2212 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 goto out;
2214
2215 /*
2216 * create a vma struct for an anonymous mapping
2217 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002218 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002219 if (!vma) {
2220 vm_unacct_memory(len >> PAGE_SHIFT);
2221 return -ENOMEM;
2222 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223
Rik van Riel5beb4932010-03-05 13:42:07 -08002224 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225 vma->vm_mm = mm;
2226 vma->vm_start = addr;
2227 vma->vm_end = addr + len;
2228 vma->vm_pgoff = pgoff;
2229 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002230 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 vma_link(mm, vma, prev, rb_link, rb_parent);
2232out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002233 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 mm->total_vm += len >> PAGE_SHIFT;
2235 if (flags & VM_LOCKED) {
Rik van Rielba470de2008-10-18 20:26:50 -07002236 if (!mlock_vma_pages_range(vma, addr, addr + len))
2237 mm->locked_vm += (len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002238 }
2239 return addr;
2240}
2241
2242EXPORT_SYMBOL(do_brk);
2243
2244/* Release all mmaps. */
2245void exit_mmap(struct mm_struct *mm)
2246{
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002247 struct mmu_gather tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002248 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002249 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002250 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002252 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002253 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002254
Rik van Rielba470de2008-10-18 20:26:50 -07002255 if (mm->locked_vm) {
2256 vma = mm->mmap;
2257 while (vma) {
2258 if (vma->vm_flags & VM_LOCKED)
2259 munlock_vma_pages_all(vma);
2260 vma = vma->vm_next;
2261 }
2262 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002263
2264 arch_exit_mmap(mm);
2265
Rik van Rielba470de2008-10-18 20:26:50 -07002266 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002267 if (!vma) /* Can happen if dup_mmap() received an OOM */
2268 return;
2269
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002271 flush_cache_mm(mm);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002272 tlb_gather_mmu(&tlb, mm, 1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002273 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002274 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002275 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276 vm_unacct_memory(nr_accounted);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002277
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002278 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
2279 tlb_finish_mmu(&tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002282 * Walk the list again, actually closing and freeing it,
2283 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002285 while (vma)
2286 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002287
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002288 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289}
2290
2291/* Insert vm structure into process list sorted by address
2292 * and into the inode's i_mmap tree. If vm_file is non-NULL
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002293 * then i_mmap_mutex is taken here.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 */
2295int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2296{
2297 struct vm_area_struct * __vma, * prev;
2298 struct rb_node ** rb_link, * rb_parent;
2299
2300 /*
2301 * The vm_pgoff of a purely anonymous vma should be irrelevant
2302 * until its first write fault, when page's anon_vma and index
2303 * are set. But now set the vm_pgoff it will almost certainly
2304 * end up with (unless mremap moves it elsewhere before that
2305 * first wfault), so /proc/pid/maps tells a consistent story.
2306 *
2307 * By setting it to reflect the virtual start address of the
2308 * vma, merges and splits can happen in a seamless way, just
2309 * using the existing file pgoff checks and manipulations.
2310 * Similarly in do_mmap_pgoff and in do_brk.
2311 */
2312 if (!vma->vm_file) {
2313 BUG_ON(vma->anon_vma);
2314 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2315 }
2316 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2317 if (__vma && __vma->vm_start < vma->vm_end)
2318 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002319 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002320 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002321 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322 vma_link(mm, vma, prev, rb_link, rb_parent);
2323 return 0;
2324}
2325
2326/*
2327 * Copy the vma structure to a new location in the same mm,
2328 * prior to moving page table entries, to effect an mremap move.
2329 */
2330struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2331 unsigned long addr, unsigned long len, pgoff_t pgoff)
2332{
2333 struct vm_area_struct *vma = *vmap;
2334 unsigned long vma_start = vma->vm_start;
2335 struct mm_struct *mm = vma->vm_mm;
2336 struct vm_area_struct *new_vma, *prev;
2337 struct rb_node **rb_link, *rb_parent;
2338 struct mempolicy *pol;
2339
2340 /*
2341 * If anonymous vma has not yet been faulted, update new pgoff
2342 * to match new location, to increase its chance of merging.
2343 */
2344 if (!vma->vm_file && !vma->anon_vma)
2345 pgoff = addr >> PAGE_SHIFT;
2346
2347 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2348 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2349 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2350 if (new_vma) {
2351 /*
2352 * Source vma may have been merged into new_vma
2353 */
2354 if (vma_start >= new_vma->vm_start &&
2355 vma_start < new_vma->vm_end)
2356 *vmap = new_vma;
2357 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002358 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 if (new_vma) {
2360 *new_vma = *vma;
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002361 pol = mpol_dup(vma_policy(vma));
Rik van Riel5beb4932010-03-05 13:42:07 -08002362 if (IS_ERR(pol))
2363 goto out_free_vma;
2364 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2365 if (anon_vma_clone(new_vma, vma))
2366 goto out_free_mempol;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002367 vma_set_policy(new_vma, pol);
2368 new_vma->vm_start = addr;
2369 new_vma->vm_end = addr + len;
2370 new_vma->vm_pgoff = pgoff;
Matt Helsley925d1c42008-04-29 01:01:36 -07002371 if (new_vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002372 get_file(new_vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07002373 if (vma->vm_flags & VM_EXECUTABLE)
2374 added_exe_file_vma(mm);
2375 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002376 if (new_vma->vm_ops && new_vma->vm_ops->open)
2377 new_vma->vm_ops->open(new_vma);
2378 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2379 }
2380 }
2381 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002382
2383 out_free_mempol:
2384 mpol_put(pol);
2385 out_free_vma:
2386 kmem_cache_free(vm_area_cachep, new_vma);
2387 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002389
2390/*
2391 * Return true if the calling process may expand its vm space by the passed
2392 * number of pages
2393 */
2394int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2395{
2396 unsigned long cur = mm->total_vm; /* pages */
2397 unsigned long lim;
2398
Jiri Slaby59e99e52010-03-05 13:41:44 -08002399 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002400
2401 if (cur + npages > lim)
2402 return 0;
2403 return 1;
2404}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002405
2406
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002407static int special_mapping_fault(struct vm_area_struct *vma,
2408 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002409{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002410 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002411 struct page **pages;
2412
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002413 /*
2414 * special mappings have no vm_file, and in that case, the mm
2415 * uses vm_pgoff internally. So we have to subtract it from here.
2416 * We are allowed to do this because we are the mm; do not copy
2417 * this code into drivers!
2418 */
2419 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002420
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002421 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2422 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002423
2424 if (*pages) {
2425 struct page *page = *pages;
2426 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002427 vmf->page = page;
2428 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002429 }
2430
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002431 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002432}
2433
2434/*
2435 * Having a close hook prevents vma merging regardless of flags.
2436 */
2437static void special_mapping_close(struct vm_area_struct *vma)
2438{
2439}
2440
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002441static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002442 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002443 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002444};
2445
2446/*
2447 * Called with mm->mmap_sem held for writing.
2448 * Insert a new vma covering the given region, with the given flags.
2449 * Its pages are supplied by the given array of struct page *.
2450 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2451 * The region past the last page supplied will always produce SIGBUS.
2452 * The array pointer and the pages it points to are assumed to stay alive
2453 * for as long as this mapping might exist.
2454 */
2455int install_special_mapping(struct mm_struct *mm,
2456 unsigned long addr, unsigned long len,
2457 unsigned long vm_flags, struct page **pages)
2458{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002459 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002460 struct vm_area_struct *vma;
2461
2462 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2463 if (unlikely(vma == NULL))
2464 return -ENOMEM;
2465
Rik van Riel5beb4932010-03-05 13:42:07 -08002466 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002467 vma->vm_mm = mm;
2468 vma->vm_start = addr;
2469 vma->vm_end = addr + len;
2470
Nick Piggin2f987352008-02-02 03:08:53 +01002471 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002472 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002473
2474 vma->vm_ops = &special_mapping_vmops;
2475 vma->vm_private_data = pages;
2476
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002477 ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
2478 if (ret)
2479 goto out;
2480
2481 ret = insert_vm_struct(mm, vma);
2482 if (ret)
2483 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002484
2485 mm->total_vm += len >> PAGE_SHIFT;
2486
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002487 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002488
Roland McGrathfa5dc222007-02-08 14:20:41 -08002489 return 0;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002490
2491out:
2492 kmem_cache_free(vm_area_cachep, vma);
2493 return ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002494}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002495
2496static DEFINE_MUTEX(mm_all_locks_mutex);
2497
Peter Zijlstra454ed842008-08-11 09:30:25 +02002498static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002499{
Rik van Riel012f1802010-08-09 17:18:40 -07002500 if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002501 /*
2502 * The LSB of head.next can't change from under us
2503 * because we hold the mm_all_locks_mutex.
2504 */
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002505 mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002506 /*
2507 * We can safely modify head.next after taking the
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002508 * anon_vma->root->mutex. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002509 * the same anon_vma we won't take it again.
2510 *
2511 * No need of atomic instructions here, head.next
2512 * can't change from under us thanks to the
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002513 * anon_vma->root->mutex.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002514 */
2515 if (__test_and_set_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002516 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002517 BUG();
2518 }
2519}
2520
Peter Zijlstra454ed842008-08-11 09:30:25 +02002521static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002522{
2523 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2524 /*
2525 * AS_MM_ALL_LOCKS can't change from under us because
2526 * we hold the mm_all_locks_mutex.
2527 *
2528 * Operations on ->flags have to be atomic because
2529 * even if AS_MM_ALL_LOCKS is stable thanks to the
2530 * mm_all_locks_mutex, there may be other cpus
2531 * changing other bitflags in parallel to us.
2532 */
2533 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2534 BUG();
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002535 mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002536 }
2537}
2538
2539/*
2540 * This operation locks against the VM for all pte/vma/mm related
2541 * operations that could ever happen on a certain mm. This includes
2542 * vmtruncate, try_to_unmap, and all page faults.
2543 *
2544 * The caller must take the mmap_sem in write mode before calling
2545 * mm_take_all_locks(). The caller isn't allowed to release the
2546 * mmap_sem until mm_drop_all_locks() returns.
2547 *
2548 * mmap_sem in write mode is required in order to block all operations
2549 * that could modify pagetables and free pages without need of
2550 * altering the vma layout (for example populate_range() with
2551 * nonlinear vmas). It's also needed in write mode to avoid new
2552 * anon_vmas to be associated with existing vmas.
2553 *
2554 * A single task can't take more than one mm_take_all_locks() in a row
2555 * or it would deadlock.
2556 *
2557 * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in
2558 * mapping->flags avoid to take the same lock twice, if more than one
2559 * vma in this mm is backed by the same anon_vma or address_space.
2560 *
2561 * We can take all the locks in random order because the VM code
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002562 * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002563 * takes more than one of them in a row. Secondly we're protected
2564 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2565 *
2566 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2567 * that may have to take thousand of locks.
2568 *
2569 * mm_take_all_locks() can fail if it's interrupted by signals.
2570 */
2571int mm_take_all_locks(struct mm_struct *mm)
2572{
2573 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002574 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002575 int ret = -EINTR;
2576
2577 BUG_ON(down_read_trylock(&mm->mmap_sem));
2578
2579 mutex_lock(&mm_all_locks_mutex);
2580
2581 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2582 if (signal_pending(current))
2583 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002584 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02002585 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002586 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002587
2588 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2589 if (signal_pending(current))
2590 goto out_unlock;
2591 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002592 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2593 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002594 }
2595
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002596 ret = 0;
2597
2598out_unlock:
2599 if (ret)
2600 mm_drop_all_locks(mm);
2601
2602 return ret;
2603}
2604
2605static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2606{
Rik van Riel012f1802010-08-09 17:18:40 -07002607 if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002608 /*
2609 * The LSB of head.next can't change to 0 from under
2610 * us because we hold the mm_all_locks_mutex.
2611 *
2612 * We must however clear the bitflag before unlocking
2613 * the vma so the users using the anon_vma->head will
2614 * never see our bitflag.
2615 *
2616 * No need of atomic instructions here, head.next
2617 * can't change from under us until we release the
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002618 * anon_vma->root->mutex.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002619 */
2620 if (!__test_and_clear_bit(0, (unsigned long *)
Rik van Riel012f1802010-08-09 17:18:40 -07002621 &anon_vma->root->head.next))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002622 BUG();
Rik van Rielcba48b92010-08-09 17:18:38 -07002623 anon_vma_unlock(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002624 }
2625}
2626
2627static void vm_unlock_mapping(struct address_space *mapping)
2628{
2629 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2630 /*
2631 * AS_MM_ALL_LOCKS can't change to 0 from under us
2632 * because we hold the mm_all_locks_mutex.
2633 */
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002634 mutex_unlock(&mapping->i_mmap_mutex);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002635 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
2636 &mapping->flags))
2637 BUG();
2638 }
2639}
2640
2641/*
2642 * The mmap_sem cannot be released by the caller until
2643 * mm_drop_all_locks() returns.
2644 */
2645void mm_drop_all_locks(struct mm_struct *mm)
2646{
2647 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002648 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002649
2650 BUG_ON(down_read_trylock(&mm->mmap_sem));
2651 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
2652
2653 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2654 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002655 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2656 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002657 if (vma->vm_file && vma->vm_file->f_mapping)
2658 vm_unlock_mapping(vma->vm_file->f_mapping);
2659 }
2660
2661 mutex_unlock(&mm_all_locks_mutex);
2662}
David Howells8feae132009-01-08 12:04:47 +00002663
2664/*
2665 * initialise the VMA slab
2666 */
2667void __init mmap_init(void)
2668{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07002669 int ret;
2670
2671 ret = percpu_counter_init(&vm_committed_as, 0);
2672 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00002673}