blob: f54b235f29a98c3b3a91c2c1e6b4b50ef5e8f287 [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>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040025#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#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>
Srikar Dronamraju2b144492012-02-09 14:56:42 +053033#include <linux/uprobes.h>
Michel Lespinassed3737182012-12-11 16:01:38 -080034#include <linux/rbtree_augmented.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36#include <asm/uaccess.h>
37#include <asm/cacheflush.h>
38#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020039#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Jan Beulich42b77722008-07-23 21:27:10 -070041#include "internal.h"
42
Kirill Korotaev3a459752006-09-07 14:17:04 +040043#ifndef arch_mmap_check
44#define arch_mmap_check(addr, len, flags) (0)
45#endif
46
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080047#ifndef arch_rebalance_pgtables
48#define arch_rebalance_pgtables(addr, len) (addr)
49#endif
50
Hugh Dickinse0da3822005-04-19 13:29:15 -070051static void unmap_region(struct mm_struct *mm,
52 struct vm_area_struct *vma, struct vm_area_struct *prev,
53 unsigned long start, unsigned long end);
54
Linus Torvalds1da177e2005-04-16 15:20:36 -070055/* description of effects of mapping type and prot in current implementation.
56 * this is due to the limited x86 page protection hardware. The expected
57 * behavior is in parens:
58 *
59 * map_type prot
60 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
61 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
62 * w: (no) no w: (no) no w: (yes) yes w: (no) no
63 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
64 *
65 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (copy) copy w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 */
70pgprot_t protection_map[16] = {
71 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
72 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
73};
74
Hugh Dickins804af2c2006-07-26 21:39:49 +010075pgprot_t vm_get_page_prot(unsigned long vm_flags)
76{
Dave Kleikampb845f312008-07-08 00:28:51 +100077 return __pgprot(pgprot_val(protection_map[vm_flags &
78 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
79 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010080}
81EXPORT_SYMBOL(vm_get_page_prot);
82
Shaohua Li34679d72011-05-24 17:11:18 -070083int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
84int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070085int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Shaohua Li34679d72011-05-24 17:11:18 -070086/*
87 * Make sure vm_committed_as in one cacheline and not cacheline shared with
88 * other variables. It can be updated by several CPUs frequently.
89 */
90struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
92/*
K. Y. Srinivasan997071b2012-11-15 14:34:42 -080093 * The global memory commitment made in the system can be a metric
94 * that can be used to drive ballooning decisions when Linux is hosted
95 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
96 * balancing memory across competing virtual machines that are hosted.
97 * Several metrics drive this policy engine including the guest reported
98 * memory commitment.
99 */
100unsigned long vm_memory_committed(void)
101{
102 return percpu_counter_read_positive(&vm_committed_as);
103}
104EXPORT_SYMBOL_GPL(vm_memory_committed);
105
106/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 * Check that a process has enough memory to allocate a new virtual
108 * mapping. 0 means there is enough memory for the allocation to
109 * succeed and -ENOMEM implies there is not.
110 *
111 * We currently support three overcommit policies, which are set via the
112 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
113 *
114 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
115 * Additional code 2002 Jul 20 by Robert Love.
116 *
117 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
118 *
119 * Note this is a helper function intended to be used by LSMs which
120 * wish to use this logic.
121 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700122int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123{
124 unsigned long free, allowed;
125
126 vm_acct_memory(pages);
127
128 /*
129 * Sometimes we want to use more memory than we have
130 */
131 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
132 return 0;
133
134 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -0700135 free = global_page_state(NR_FREE_PAGES);
136 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
Dmitry Finkc15bef32011-07-25 17:12:19 -0700138 /*
139 * shmem pages shouldn't be counted as free in this
140 * case, they can't be purged, only swapped out, and
141 * that won't affect the overall amount of available
142 * memory in the system.
143 */
144 free -= global_page_state(NR_SHMEM);
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 free += nr_swap_pages;
147
148 /*
149 * Any slabs which are created with the
150 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
151 * which are reclaimable, under pressure. The dentry
152 * cache and most inode caches should fall into this
153 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700154 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -0700157 * Leave reserved pages. The pages are not for anonymous pages.
158 */
159 if (free <= totalreserve_pages)
160 goto error;
161 else
162 free -= totalreserve_pages;
163
164 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 * Leave the last 3% for root
166 */
167 if (!cap_sys_admin)
168 free -= free / 32;
169
170 if (free > pages)
171 return 0;
172
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700173 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 }
175
176 allowed = (totalram_pages - hugetlb_total_pages())
177 * sysctl_overcommit_ratio / 100;
178 /*
179 * Leave the last 3% for root
180 */
181 if (!cap_sys_admin)
182 allowed -= allowed / 32;
183 allowed += total_swap_pages;
184
185 /* Don't let a single process grow too big:
186 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -0700187 if (mm)
188 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700190 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700192error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 vm_unacct_memory(pages);
194
195 return -ENOMEM;
196}
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198/*
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700199 * Requires inode->i_mapping->i_mmap_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 */
201static void __remove_shared_vm_struct(struct vm_area_struct *vma,
202 struct file *file, struct address_space *mapping)
203{
204 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800205 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 if (vma->vm_flags & VM_SHARED)
207 mapping->i_mmap_writable--;
208
209 flush_dcache_mmap_lock(mapping);
210 if (unlikely(vma->vm_flags & VM_NONLINEAR))
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700211 list_del_init(&vma->shared.nonlinear);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700213 vma_interval_tree_remove(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 flush_dcache_mmap_unlock(mapping);
215}
216
217/*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700218 * Unlink a file-based vm structure from its interval tree, to hide
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700219 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700221void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222{
223 struct file *file = vma->vm_file;
224
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 if (file) {
226 struct address_space *mapping = file->f_mapping;
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700227 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 __remove_shared_vm_struct(vma, file, mapping);
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700229 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700231}
232
233/*
234 * Close a vm structure and free it, returning the next.
235 */
236static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
237{
238 struct vm_area_struct *next = vma->vm_next;
239
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700240 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 if (vma->vm_ops && vma->vm_ops->close)
242 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700243 if (vma->vm_file)
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700244 fput(vma->vm_file);
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700245 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700247 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248}
249
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -0700250static unsigned long do_brk(unsigned long addr, unsigned long len);
251
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100252SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253{
254 unsigned long rlim, retval;
255 unsigned long newbrk, oldbrk;
256 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700257 unsigned long min_brk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
259 down_write(&mm->mmap_sem);
260
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700261#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800262 /*
263 * CONFIG_COMPAT_BRK can still be overridden by setting
264 * randomize_va_space to 2, which will still cause mm->start_brk
265 * to be arbitrarily shifted
266 */
Jiri Kosina4471a672011-04-14 15:22:09 -0700267 if (current->brk_randomized)
Jiri Kosina5520e892011-01-13 15:47:23 -0800268 min_brk = mm->start_brk;
269 else
270 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700271#else
272 min_brk = mm->start_brk;
273#endif
274 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700276
277 /*
278 * Check against rlimit here. If this check is done later after the test
279 * of oldbrk with newbrk then it can escape the test and let the data
280 * segment grow beyond its set limit the in case where the limit is
281 * not page aligned -Ram Gupta
282 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800283 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100284 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
285 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700286 goto out;
287
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 newbrk = PAGE_ALIGN(brk);
289 oldbrk = PAGE_ALIGN(mm->brk);
290 if (oldbrk == newbrk)
291 goto set_brk;
292
293 /* Always allow shrinking brk. */
294 if (brk <= mm->brk) {
295 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
296 goto set_brk;
297 goto out;
298 }
299
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 /* Check against existing mmap mappings. */
301 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
302 goto out;
303
304 /* Ok, looks good - let it rip. */
305 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
306 goto out;
307set_brk:
308 mm->brk = brk;
309out:
310 retval = mm->brk;
311 up_write(&mm->mmap_sem);
312 return retval;
313}
314
Michel Lespinassed3737182012-12-11 16:01:38 -0800315static long vma_compute_subtree_gap(struct vm_area_struct *vma)
316{
317 unsigned long max, subtree_gap;
318 max = vma->vm_start;
319 if (vma->vm_prev)
320 max -= vma->vm_prev->vm_end;
321 if (vma->vm_rb.rb_left) {
322 subtree_gap = rb_entry(vma->vm_rb.rb_left,
323 struct vm_area_struct, vm_rb)->rb_subtree_gap;
324 if (subtree_gap > max)
325 max = subtree_gap;
326 }
327 if (vma->vm_rb.rb_right) {
328 subtree_gap = rb_entry(vma->vm_rb.rb_right,
329 struct vm_area_struct, vm_rb)->rb_subtree_gap;
330 if (subtree_gap > max)
331 max = subtree_gap;
332 }
333 return max;
334}
335
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700336#ifdef CONFIG_DEBUG_VM_RB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337static int browse_rb(struct rb_root *root)
338{
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800339 int i = 0, j, bug = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 struct rb_node *nd, *pn = NULL;
341 unsigned long prev = 0, pend = 0;
342
343 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
344 struct vm_area_struct *vma;
345 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800346 if (vma->vm_start < prev) {
347 printk("vm_start %lx prev %lx\n", vma->vm_start, prev);
348 bug = 1;
349 }
350 if (vma->vm_start < pend) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800352 bug = 1;
353 }
354 if (vma->vm_start > vma->vm_end) {
355 printk("vm_end %lx < vm_start %lx\n",
356 vma->vm_end, vma->vm_start);
357 bug = 1;
358 }
359 if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
360 printk("free gap %lx, correct %lx\n",
361 vma->rb_subtree_gap,
362 vma_compute_subtree_gap(vma));
363 bug = 1;
364 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 i++;
366 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800367 prev = vma->vm_start;
368 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 }
370 j = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800371 for (nd = pn; nd; nd = rb_prev(nd))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 j++;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800373 if (i != j) {
374 printk("backwards %d, forwards %d\n", j, i);
375 bug = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800377 return bug ? -1 : i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378}
379
Michel Lespinassed3737182012-12-11 16:01:38 -0800380static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
381{
382 struct rb_node *nd;
383
384 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
385 struct vm_area_struct *vma;
386 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
387 BUG_ON(vma != ignore &&
388 vma->rb_subtree_gap != vma_compute_subtree_gap(vma));
389 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390}
391
392void validate_mm(struct mm_struct *mm)
393{
394 int bug = 0;
395 int i = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800396 unsigned long highest_address = 0;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700397 struct vm_area_struct *vma = mm->mmap;
398 while (vma) {
399 struct anon_vma_chain *avc;
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800400 vma_lock_anon_vma(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700401 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
402 anon_vma_interval_tree_verify(avc);
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800403 vma_unlock_anon_vma(vma);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800404 highest_address = vma->vm_end;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700405 vma = vma->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 i++;
407 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800408 if (i != mm->map_count) {
409 printk("map_count %d vm_next %d\n", mm->map_count, i);
410 bug = 1;
411 }
412 if (highest_address != mm->highest_vm_end) {
413 printk("mm->highest_vm_end %lx, found %lx\n",
414 mm->highest_vm_end, highest_address);
415 bug = 1;
416 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 i = browse_rb(&mm->mm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800418 if (i != mm->map_count) {
419 printk("map_count %d rb %d\n", mm->map_count, i);
420 bug = 1;
421 }
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200422 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423}
424#else
Michel Lespinassed3737182012-12-11 16:01:38 -0800425#define validate_mm_rb(root, ignore) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426#define validate_mm(mm) do { } while (0)
427#endif
428
Michel Lespinassed3737182012-12-11 16:01:38 -0800429RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb,
430 unsigned long, rb_subtree_gap, vma_compute_subtree_gap)
431
432/*
433 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
434 * vma->vm_prev->vm_end values changed, without modifying the vma's position
435 * in the rbtree.
436 */
437static void vma_gap_update(struct vm_area_struct *vma)
438{
439 /*
440 * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
441 * function that does exacltly what we want.
442 */
443 vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
444}
445
446static inline void vma_rb_insert(struct vm_area_struct *vma,
447 struct rb_root *root)
448{
449 /* All rb_subtree_gap values must be consistent prior to insertion */
450 validate_mm_rb(root, NULL);
451
452 rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
453}
454
455static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
456{
457 /*
458 * All rb_subtree_gap values must be consistent prior to erase,
459 * with the possible exception of the vma being erased.
460 */
461 validate_mm_rb(root, vma);
462
463 /*
464 * Note rb_erase_augmented is a fairly large inline function,
465 * so make sure we instantiate it only once with our desired
466 * augmented rbtree callbacks.
467 */
468 rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
469}
470
Michel Lespinassebf181b92012-10-08 16:31:39 -0700471/*
472 * vma has some anon_vma assigned, and is already inserted on that
473 * anon_vma's interval trees.
474 *
475 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
476 * vma must be removed from the anon_vma's interval trees using
477 * anon_vma_interval_tree_pre_update_vma().
478 *
479 * After the update, the vma will be reinserted using
480 * anon_vma_interval_tree_post_update_vma().
481 *
482 * The entire update must be protected by exclusive mmap_sem and by
483 * the root anon_vma's mutex.
484 */
485static inline void
486anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
487{
488 struct anon_vma_chain *avc;
489
490 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
491 anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
492}
493
494static inline void
495anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
496{
497 struct anon_vma_chain *avc;
498
499 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
500 anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
501}
502
Hugh Dickins6597d782012-10-08 16:29:07 -0700503static int find_vma_links(struct mm_struct *mm, unsigned long addr,
504 unsigned long end, struct vm_area_struct **pprev,
505 struct rb_node ***rb_link, struct rb_node **rb_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506{
Hugh Dickins6597d782012-10-08 16:29:07 -0700507 struct rb_node **__rb_link, *__rb_parent, *rb_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
509 __rb_link = &mm->mm_rb.rb_node;
510 rb_prev = __rb_parent = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511
512 while (*__rb_link) {
513 struct vm_area_struct *vma_tmp;
514
515 __rb_parent = *__rb_link;
516 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
517
518 if (vma_tmp->vm_end > addr) {
Hugh Dickins6597d782012-10-08 16:29:07 -0700519 /* Fail if an existing vma overlaps the area */
520 if (vma_tmp->vm_start < end)
521 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 __rb_link = &__rb_parent->rb_left;
523 } else {
524 rb_prev = __rb_parent;
525 __rb_link = &__rb_parent->rb_right;
526 }
527 }
528
529 *pprev = NULL;
530 if (rb_prev)
531 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
532 *rb_link = __rb_link;
533 *rb_parent = __rb_parent;
Hugh Dickins6597d782012-10-08 16:29:07 -0700534 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535}
536
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
538 struct rb_node **rb_link, struct rb_node *rb_parent)
539{
Michel Lespinassed3737182012-12-11 16:01:38 -0800540 /* Update tracking information for the gap following the new vma. */
541 if (vma->vm_next)
542 vma_gap_update(vma->vm_next);
543 else
544 mm->highest_vm_end = vma->vm_end;
545
546 /*
547 * vma->vm_prev wasn't known when we followed the rbtree to find the
548 * correct insertion point for that vma. As a result, we could not
549 * update the vma vm_rb parents rb_subtree_gap values on the way down.
550 * So, we first insert the vma with a zero rb_subtree_gap value
551 * (to be consistent with what we did on the way down), and then
552 * immediately update the gap to the correct value. Finally we
553 * rebalance the rbtree after all augmented values have been set.
554 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
Michel Lespinassed3737182012-12-11 16:01:38 -0800556 vma->rb_subtree_gap = 0;
557 vma_gap_update(vma);
558 vma_rb_insert(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559}
560
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700561static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562{
ZhenwenXu48aae422009-01-06 14:40:21 -0800563 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 file = vma->vm_file;
566 if (file) {
567 struct address_space *mapping = file->f_mapping;
568
569 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800570 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 if (vma->vm_flags & VM_SHARED)
572 mapping->i_mmap_writable++;
573
574 flush_dcache_mmap_lock(mapping);
575 if (unlikely(vma->vm_flags & VM_NONLINEAR))
576 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
577 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700578 vma_interval_tree_insert(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 flush_dcache_mmap_unlock(mapping);
580 }
581}
582
583static void
584__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
585 struct vm_area_struct *prev, struct rb_node **rb_link,
586 struct rb_node *rb_parent)
587{
588 __vma_link_list(mm, vma, prev, rb_parent);
589 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590}
591
592static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
593 struct vm_area_struct *prev, struct rb_node **rb_link,
594 struct rb_node *rb_parent)
595{
596 struct address_space *mapping = NULL;
597
598 if (vma->vm_file)
599 mapping = vma->vm_file->f_mapping;
600
Peter Zijlstra97a89412011-05-24 17:12:04 -0700601 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700602 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
604 __vma_link(mm, vma, prev, rb_link, rb_parent);
605 __vma_link_file(vma);
606
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700608 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609
610 mm->map_count++;
611 validate_mm(mm);
612}
613
614/*
Kautuk Consul88f6b4c2012-03-21 16:34:16 -0700615 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700616 * mm's list and rbtree. It has already been inserted into the interval tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800618static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619{
Hugh Dickins6597d782012-10-08 16:29:07 -0700620 struct vm_area_struct *prev;
ZhenwenXu48aae422009-01-06 14:40:21 -0800621 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622
Hugh Dickins6597d782012-10-08 16:29:07 -0700623 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
624 &prev, &rb_link, &rb_parent))
625 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 __vma_link(mm, vma, prev, rb_link, rb_parent);
627 mm->map_count++;
628}
629
630static inline void
631__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
632 struct vm_area_struct *prev)
633{
Michel Lespinassed3737182012-12-11 16:01:38 -0800634 struct vm_area_struct *next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700635
Michel Lespinassed3737182012-12-11 16:01:38 -0800636 vma_rb_erase(vma, &mm->mm_rb);
637 prev->vm_next = next = vma->vm_next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700638 if (next)
639 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 if (mm->mmap_cache == vma)
641 mm->mmap_cache = prev;
642}
643
644/*
645 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
646 * is already present in an i_mmap tree without adjusting the tree.
647 * The following helper function should be used when such adjustments
648 * are necessary. The "insert" vma (if any) is to be inserted
649 * before we drop the necessary locks.
650 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800651int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
653{
654 struct mm_struct *mm = vma->vm_mm;
655 struct vm_area_struct *next = vma->vm_next;
656 struct vm_area_struct *importer = NULL;
657 struct address_space *mapping = NULL;
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700658 struct rb_root *root = NULL;
Rik van Riel012f18002010-08-09 17:18:40 -0700659 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 struct file *file = vma->vm_file;
Michel Lespinassed3737182012-12-11 16:01:38 -0800661 bool start_changed = false, end_changed = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 long adjust_next = 0;
663 int remove_next = 0;
664
665 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700666 struct vm_area_struct *exporter = NULL;
667
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 if (end >= next->vm_end) {
669 /*
670 * vma expands, overlapping all the next, and
671 * perhaps the one after too (mprotect case 6).
672 */
673again: remove_next = 1 + (end > next->vm_end);
674 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700675 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 importer = vma;
677 } else if (end > next->vm_start) {
678 /*
679 * vma expands, overlapping part of the next:
680 * mprotect case 5 shifting the boundary up.
681 */
682 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700683 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 importer = vma;
685 } else if (end < vma->vm_end) {
686 /*
687 * vma shrinks, and !insert tells it's not
688 * split_vma inserting another: so it must be
689 * mprotect case 4 shifting the boundary down.
690 */
691 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700692 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 importer = next;
694 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695
Rik van Riel5beb4932010-03-05 13:42:07 -0800696 /*
697 * Easily overlooked: when mprotect shifts the boundary,
698 * make sure the expanding vma has anon_vma set if the
699 * shrinking vma had, to cover any anon pages imported.
700 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700701 if (exporter && exporter->anon_vma && !importer->anon_vma) {
702 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800703 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700704 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800705 }
706 }
707
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 if (file) {
709 mapping = file->f_mapping;
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530710 if (!(vma->vm_flags & VM_NONLINEAR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 root = &mapping->i_mmap;
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530712 uprobe_munmap(vma, vma->vm_start, vma->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530713
714 if (adjust_next)
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530715 uprobe_munmap(next, next->vm_start,
716 next->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530717 }
718
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700719 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 if (insert) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 /*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700722 * Put into interval tree now, so instantiated pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 * are visible to arm/parisc __flush_dcache_page
724 * throughout; but we cannot insert into address
725 * space until vma start or end is updated.
726 */
727 __vma_link_file(insert);
728 }
729 }
730
Andrea Arcangeli94fcc582011-01-13 15:47:08 -0800731 vma_adjust_trans_huge(vma, start, end, adjust_next);
732
Michel Lespinassebf181b92012-10-08 16:31:39 -0700733 anon_vma = vma->anon_vma;
734 if (!anon_vma && adjust_next)
735 anon_vma = next->anon_vma;
736 if (anon_vma) {
Michel Lespinasseca42b262012-10-08 16:30:01 -0700737 VM_BUG_ON(adjust_next && next->anon_vma &&
738 anon_vma != next->anon_vma);
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000739 anon_vma_lock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700740 anon_vma_interval_tree_pre_update_vma(vma);
741 if (adjust_next)
742 anon_vma_interval_tree_pre_update_vma(next);
743 }
Rik van Riel012f18002010-08-09 17:18:40 -0700744
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 if (root) {
746 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700747 vma_interval_tree_remove(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700749 vma_interval_tree_remove(next, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 }
751
Michel Lespinassed3737182012-12-11 16:01:38 -0800752 if (start != vma->vm_start) {
753 vma->vm_start = start;
754 start_changed = true;
755 }
756 if (end != vma->vm_end) {
757 vma->vm_end = end;
758 end_changed = true;
759 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 vma->vm_pgoff = pgoff;
761 if (adjust_next) {
762 next->vm_start += adjust_next << PAGE_SHIFT;
763 next->vm_pgoff += adjust_next;
764 }
765
766 if (root) {
767 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700768 vma_interval_tree_insert(next, root);
769 vma_interval_tree_insert(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 flush_dcache_mmap_unlock(mapping);
771 }
772
773 if (remove_next) {
774 /*
775 * vma_merge has merged next into vma, and needs
776 * us to remove next before dropping the locks.
777 */
778 __vma_unlink(mm, next, vma);
779 if (file)
780 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 } else if (insert) {
782 /*
783 * split_vma has split insert from vma, and needs
784 * us to insert it before dropping the locks
785 * (it may either follow vma or precede it).
786 */
787 __insert_vm_struct(mm, insert);
Michel Lespinassed3737182012-12-11 16:01:38 -0800788 } else {
789 if (start_changed)
790 vma_gap_update(vma);
791 if (end_changed) {
792 if (!next)
793 mm->highest_vm_end = end;
794 else if (!adjust_next)
795 vma_gap_update(next);
796 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 }
798
Michel Lespinassebf181b92012-10-08 16:31:39 -0700799 if (anon_vma) {
800 anon_vma_interval_tree_post_update_vma(vma);
801 if (adjust_next)
802 anon_vma_interval_tree_post_update_vma(next);
Rik van Riel012f18002010-08-09 17:18:40 -0700803 anon_vma_unlock(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700804 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700806 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530808 if (root) {
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100809 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530810
811 if (adjust_next)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100812 uprobe_mmap(next);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530813 }
814
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700816 if (file) {
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530817 uprobe_munmap(next, next->vm_start, next->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700819 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800820 if (next->anon_vma)
821 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700823 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 kmem_cache_free(vm_area_cachep, next);
825 /*
826 * In mprotect's case 6 (see comments on vma_merge),
827 * we must remove another next too. It would clutter
828 * up the code too much to do both in one go.
829 */
Michel Lespinassed3737182012-12-11 16:01:38 -0800830 next = vma->vm_next;
831 if (remove_next == 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 goto again;
Michel Lespinassed3737182012-12-11 16:01:38 -0800833 else if (next)
834 vma_gap_update(next);
835 else
836 mm->highest_vm_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530838 if (insert && file)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100839 uprobe_mmap(insert);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
841 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800842
843 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844}
845
846/*
847 * If the vma has a ->close operation then the driver probably needs to release
848 * per-vma resources, so we don't attempt to merge those.
849 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850static inline int is_mergeable_vma(struct vm_area_struct *vma,
851 struct file *file, unsigned long vm_flags)
852{
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -0700853 if (vma->vm_flags ^ vm_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 return 0;
855 if (vma->vm_file != file)
856 return 0;
857 if (vma->vm_ops && vma->vm_ops->close)
858 return 0;
859 return 1;
860}
861
862static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
Shaohua Li965f55d2011-05-24 17:11:20 -0700863 struct anon_vma *anon_vma2,
864 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865{
Shaohua Li965f55d2011-05-24 17:11:20 -0700866 /*
867 * The list_is_singular() test is to avoid merging VMA cloned from
868 * parents. This can improve scalability caused by anon_vma lock.
869 */
870 if ((!anon_vma1 || !anon_vma2) && (!vma ||
871 list_is_singular(&vma->anon_vma_chain)))
872 return 1;
873 return anon_vma1 == anon_vma2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874}
875
876/*
877 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
878 * in front of (at a lower virtual address and file offset than) the vma.
879 *
880 * We cannot merge two vmas if they have differently assigned (non-NULL)
881 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
882 *
883 * We don't check here for the merged mmap wrapping around the end of pagecache
884 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
885 * wrap, nor mmaps which cover the final page at index -1UL.
886 */
887static int
888can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
889 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
890{
891 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700892 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 if (vma->vm_pgoff == vm_pgoff)
894 return 1;
895 }
896 return 0;
897}
898
899/*
900 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
901 * beyond (at a higher virtual address and file offset than) the vma.
902 *
903 * We cannot merge two vmas if they have differently assigned (non-NULL)
904 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
905 */
906static int
907can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
908 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
909{
910 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700911 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 pgoff_t vm_pglen;
913 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
914 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
915 return 1;
916 }
917 return 0;
918}
919
920/*
921 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
922 * whether that can be merged with its predecessor or its successor.
923 * Or both (it neatly fills a hole).
924 *
925 * In most cases - when called for mmap, brk or mremap - [addr,end) is
926 * certain not to be mapped by the time vma_merge is called; but when
927 * called for mprotect, it is certain to be already mapped (either at
928 * an offset within prev, or at the start of next), and the flags of
929 * this area are about to be changed to vm_flags - and the no-change
930 * case has already been eliminated.
931 *
932 * The following mprotect cases have to be considered, where AAAA is
933 * the area passed down from mprotect_fixup, never extending beyond one
934 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
935 *
936 * AAAA AAAA AAAA AAAA
937 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
938 * cannot merge might become might become might become
939 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
940 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
941 * mremap move: PPPPNNNNNNNN 8
942 * AAAA
943 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
944 * might become case 1 below case 2 below case 3 below
945 *
946 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
947 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
948 */
949struct vm_area_struct *vma_merge(struct mm_struct *mm,
950 struct vm_area_struct *prev, unsigned long addr,
951 unsigned long end, unsigned long vm_flags,
952 struct anon_vma *anon_vma, struct file *file,
953 pgoff_t pgoff, struct mempolicy *policy)
954{
955 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
956 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800957 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958
959 /*
960 * We later require that vma->vm_flags == vm_flags,
961 * so this tests vma->vm_flags & VM_SPECIAL, too.
962 */
963 if (vm_flags & VM_SPECIAL)
964 return NULL;
965
966 if (prev)
967 next = prev->vm_next;
968 else
969 next = mm->mmap;
970 area = next;
971 if (next && next->vm_end == end) /* cases 6, 7, 8 */
972 next = next->vm_next;
973
974 /*
975 * Can it merge with the predecessor?
976 */
977 if (prev && prev->vm_end == addr &&
978 mpol_equal(vma_policy(prev), policy) &&
979 can_vma_merge_after(prev, vm_flags,
980 anon_vma, file, pgoff)) {
981 /*
982 * OK, it can. Can we now merge in the successor as well?
983 */
984 if (next && end == next->vm_start &&
985 mpol_equal(policy, vma_policy(next)) &&
986 can_vma_merge_before(next, vm_flags,
987 anon_vma, file, pgoff+pglen) &&
988 is_mergeable_anon_vma(prev->anon_vma,
Shaohua Li965f55d2011-05-24 17:11:20 -0700989 next->anon_vma, NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800991 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 next->vm_end, prev->vm_pgoff, NULL);
993 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800994 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -0800996 if (err)
997 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -0800998 khugepaged_enter_vma_merge(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 return prev;
1000 }
1001
1002 /*
1003 * Can this new request be merged in front of next?
1004 */
1005 if (next && end == next->vm_start &&
1006 mpol_equal(policy, vma_policy(next)) &&
1007 can_vma_merge_before(next, vm_flags,
1008 anon_vma, file, pgoff+pglen)) {
1009 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001010 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 addr, prev->vm_pgoff, NULL);
1012 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001013 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001015 if (err)
1016 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001017 khugepaged_enter_vma_merge(area);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 return area;
1019 }
1020
1021 return NULL;
1022}
1023
1024/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001025 * Rough compatbility check to quickly see if it's even worth looking
1026 * at sharing an anon_vma.
1027 *
1028 * They need to have the same vm_file, and the flags can only differ
1029 * in things that mprotect may change.
1030 *
1031 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1032 * we can merge the two vma's. For example, we refuse to merge a vma if
1033 * there is a vm_ops->close() function, because that indicates that the
1034 * driver is doing some kind of reference counting. But that doesn't
1035 * really matter for the anon_vma sharing case.
1036 */
1037static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1038{
1039 return a->vm_end == b->vm_start &&
1040 mpol_equal(vma_policy(a), vma_policy(b)) &&
1041 a->vm_file == b->vm_file &&
1042 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
1043 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1044}
1045
1046/*
1047 * Do some basic sanity checking to see if we can re-use the anon_vma
1048 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1049 * the same as 'old', the other will be the new one that is trying
1050 * to share the anon_vma.
1051 *
1052 * NOTE! This runs with mm_sem held for reading, so it is possible that
1053 * the anon_vma of 'old' is concurrently in the process of being set up
1054 * by another page fault trying to merge _that_. But that's ok: if it
1055 * is being set up, that automatically means that it will be a singleton
1056 * acceptable for merging, so we can do all of this optimistically. But
1057 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
1058 *
1059 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1060 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1061 * is to return an anon_vma that is "complex" due to having gone through
1062 * a fork).
1063 *
1064 * We also make sure that the two vma's are compatible (adjacent,
1065 * and with the same memory policies). That's all stable, even with just
1066 * a read lock on the mm_sem.
1067 */
1068static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1069{
1070 if (anon_vma_compatible(a, b)) {
1071 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
1072
1073 if (anon_vma && list_is_singular(&old->anon_vma_chain))
1074 return anon_vma;
1075 }
1076 return NULL;
1077}
1078
1079/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1081 * neighbouring vmas for a suitable anon_vma, before it goes off
1082 * to allocate a new anon_vma. It checks because a repetitive
1083 * sequence of mprotects and faults may otherwise lead to distinct
1084 * anon_vmas being allocated, preventing vma merge in subsequent
1085 * mprotect.
1086 */
1087struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1088{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001089 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
1092 near = vma->vm_next;
1093 if (!near)
1094 goto try_prev;
1095
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001096 anon_vma = reusable_anon_vma(near, vma, near);
1097 if (anon_vma)
1098 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099try_prev:
Linus Torvalds9be34c92011-06-16 00:35:09 -07001100 near = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 if (!near)
1102 goto none;
1103
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001104 anon_vma = reusable_anon_vma(near, near, vma);
1105 if (anon_vma)
1106 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107none:
1108 /*
1109 * There's no absolute need to look only at touching neighbours:
1110 * we could search further afield for "compatible" anon_vmas.
1111 * But it would probably just be a waste of time searching,
1112 * or lead to too many vmas hanging off the same anon_vma.
1113 * We're trying to allow mprotect remerging later on,
1114 * not trying to minimize memory used for anon_vmas.
1115 */
1116 return NULL;
1117}
1118
1119#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001120void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 struct file *file, long pages)
1122{
1123 const unsigned long stack_flags
1124 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
1125
Huang Shijie44de9d02012-07-31 16:41:49 -07001126 mm->total_vm += pages;
1127
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 if (file) {
1129 mm->shared_vm += pages;
1130 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
1131 mm->exec_vm += pages;
1132 } else if (flags & stack_flags)
1133 mm->stack_vm += pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134}
1135#endif /* CONFIG_PROC_FS */
1136
1137/*
Al Viro40401532012-02-13 03:58:52 +00001138 * If a hint addr is less than mmap_min_addr change hint to be as
1139 * low as possible but still greater than mmap_min_addr
1140 */
1141static inline unsigned long round_hint_to_min(unsigned long hint)
1142{
1143 hint &= PAGE_MASK;
1144 if (((void *)hint != NULL) &&
1145 (hint < mmap_min_addr))
1146 return PAGE_ALIGN(mmap_min_addr);
1147 return hint;
1148}
1149
1150/*
Jianjun Kong27f5de72009-09-17 19:26:26 -07001151 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 */
1153
Al Viroe3fc6292012-05-30 20:08:42 -04001154unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 unsigned long len, unsigned long prot,
1156 unsigned long flags, unsigned long pgoff)
1157{
1158 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 struct inode *inode;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001160 vm_flags_t vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 /*
1163 * Does the application expect PROT_READ to imply PROT_EXEC?
1164 *
1165 * (the exception is when the underlying filesystem is noexec
1166 * mounted, in which case we dont add PROT_EXEC.)
1167 */
1168 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001169 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 prot |= PROT_EXEC;
1171
1172 if (!len)
1173 return -EINVAL;
1174
Eric Paris7cd94142007-11-26 18:47:40 -05001175 if (!(flags & MAP_FIXED))
1176 addr = round_hint_to_min(addr);
1177
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 /* Careful about overflows.. */
1179 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -05001180 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 return -ENOMEM;
1182
1183 /* offset overflow? */
1184 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1185 return -EOVERFLOW;
1186
1187 /* Too many mappings? */
1188 if (mm->map_count > sysctl_max_map_count)
1189 return -ENOMEM;
1190
1191 /* Obtain the address to map to. we verify (or select) it and ensure
1192 * that it represents a valid section of the address space.
1193 */
1194 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1195 if (addr & ~PAGE_MASK)
1196 return addr;
1197
1198 /* Do simple checking here so the lower-level routines won't have
1199 * to. we assume access permissions have been handled by the open
1200 * of the memory object, so we don't do any here.
1201 */
1202 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1203 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1204
Huang Shijiecdf7b342009-09-21 17:03:36 -07001205 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 if (!can_do_mlock())
1207 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 /* mlock MCL_FUTURE? */
1210 if (vm_flags & VM_LOCKED) {
1211 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001212 locked = len >> PAGE_SHIFT;
1213 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001214 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001215 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1217 return -EAGAIN;
1218 }
1219
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001220 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221
1222 if (file) {
1223 switch (flags & MAP_TYPE) {
1224 case MAP_SHARED:
1225 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1226 return -EACCES;
1227
1228 /*
1229 * Make sure we don't allow writing to an append-only
1230 * file..
1231 */
1232 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1233 return -EACCES;
1234
1235 /*
1236 * Make sure there are no mandatory locks on the file.
1237 */
1238 if (locks_verify_locked(inode))
1239 return -EAGAIN;
1240
1241 vm_flags |= VM_SHARED | VM_MAYSHARE;
1242 if (!(file->f_mode & FMODE_WRITE))
1243 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1244
1245 /* fall through */
1246 case MAP_PRIVATE:
1247 if (!(file->f_mode & FMODE_READ))
1248 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001249 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001250 if (vm_flags & VM_EXEC)
1251 return -EPERM;
1252 vm_flags &= ~VM_MAYEXEC;
1253 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001254
1255 if (!file->f_op || !file->f_op->mmap)
1256 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 break;
1258
1259 default:
1260 return -EINVAL;
1261 }
1262 } else {
1263 switch (flags & MAP_TYPE) {
1264 case MAP_SHARED:
Tejun Heoce363942008-09-03 16:09:47 +02001265 /*
1266 * Ignore pgoff.
1267 */
1268 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 vm_flags |= VM_SHARED | VM_MAYSHARE;
1270 break;
1271 case MAP_PRIVATE:
1272 /*
1273 * Set pgoff according to addr for anon_vma.
1274 */
1275 pgoff = addr >> PAGE_SHIFT;
1276 break;
1277 default:
1278 return -EINVAL;
1279 }
1280 }
1281
Mel Gorman5a6fe122009-02-10 14:02:27 +00001282 return mmap_region(file, addr, len, flags, vm_flags, pgoff);
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001283}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001284
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001285SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1286 unsigned long, prot, unsigned long, flags,
1287 unsigned long, fd, unsigned long, pgoff)
1288{
1289 struct file *file = NULL;
1290 unsigned long retval = -EBADF;
1291
1292 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001293 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001294 if (unlikely(flags & MAP_HUGETLB))
1295 return -EINVAL;
1296 file = fget(fd);
1297 if (!file)
1298 goto out;
1299 } else if (flags & MAP_HUGETLB) {
1300 struct user_struct *user = NULL;
1301 /*
1302 * VM_NORESERVE is used because the reservations will be
1303 * taken when vm_ops->mmap() is called
1304 * A dummy user value is used because we are not locking
1305 * memory so no accounting is necessary
1306 */
Steven Truelove40716e22012-03-21 16:34:14 -07001307 file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len,
Andi Kleen42d73952012-12-11 16:01:34 -08001308 VM_NORESERVE,
1309 &user, HUGETLB_ANONHUGE_INODE,
1310 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001311 if (IS_ERR(file))
1312 return PTR_ERR(file);
1313 }
1314
1315 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1316
Al Viroeb36c582012-05-30 20:17:35 -04001317 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001318 if (file)
1319 fput(file);
1320out:
1321 return retval;
1322}
1323
Christoph Hellwiga4679372010-03-10 15:21:15 -08001324#ifdef __ARCH_WANT_SYS_OLD_MMAP
1325struct mmap_arg_struct {
1326 unsigned long addr;
1327 unsigned long len;
1328 unsigned long prot;
1329 unsigned long flags;
1330 unsigned long fd;
1331 unsigned long offset;
1332};
1333
1334SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1335{
1336 struct mmap_arg_struct a;
1337
1338 if (copy_from_user(&a, arg, sizeof(a)))
1339 return -EFAULT;
1340 if (a.offset & ~PAGE_MASK)
1341 return -EINVAL;
1342
1343 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1344 a.offset >> PAGE_SHIFT);
1345}
1346#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1347
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001348/*
1349 * Some shared mappigns will want the pages marked read-only
1350 * to track write events. If so, we'll downgrade vm_page_prot
1351 * to the private version (using protection_map[] without the
1352 * VM_SHARED bit).
1353 */
1354int vma_wants_writenotify(struct vm_area_struct *vma)
1355{
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001356 vm_flags_t vm_flags = vma->vm_flags;
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001357
1358 /* If it was private or non-writable, the write bit is already clear */
1359 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1360 return 0;
1361
1362 /* The backer wishes to know when pages are first written to? */
1363 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1364 return 1;
1365
1366 /* The open routine did something to the protections already? */
1367 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001368 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001369 return 0;
1370
1371 /* Specialty mapping? */
Konstantin Khlebnikov4b6e1e32012-10-08 16:28:40 -07001372 if (vm_flags & VM_PFNMAP)
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001373 return 0;
1374
1375 /* Can the mapping track the dirty pages? */
1376 return vma->vm_file && vma->vm_file->f_mapping &&
1377 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1378}
1379
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001380/*
1381 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001382 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001383 */
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001384static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001385{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001386 /*
1387 * hugetlb has its own accounting separate from the core VM
1388 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1389 */
1390 if (file && is_file_hugepages(file))
1391 return 0;
1392
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001393 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1394}
1395
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001396unsigned long mmap_region(struct file *file, unsigned long addr,
1397 unsigned long len, unsigned long flags,
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001398 vm_flags_t vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001399{
1400 struct mm_struct *mm = current->mm;
1401 struct vm_area_struct *vma, *prev;
1402 int correct_wcount = 0;
1403 int error;
1404 struct rb_node **rb_link, *rb_parent;
1405 unsigned long charged = 0;
1406 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1407
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 /* Clear old maps */
1409 error = -ENOMEM;
1410munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07001411 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 if (do_munmap(mm, addr, len))
1413 return -ENOMEM;
1414 goto munmap_back;
1415 }
1416
1417 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001418 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 return -ENOMEM;
1420
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001421 /*
1422 * Set 'VM_NORESERVE' if we should not account for the
Mel Gorman5a6fe122009-02-10 14:02:27 +00001423 * memory use of this mapping.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001424 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001425 if ((flags & MAP_NORESERVE)) {
1426 /* We honor MAP_NORESERVE if allowed to overcommit */
1427 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1428 vm_flags |= VM_NORESERVE;
1429
1430 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1431 if (file && is_file_hugepages(file))
1432 vm_flags |= VM_NORESERVE;
1433 }
Andy Whitcroftcdfd4322008-07-23 21:27:28 -07001434
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001435 /*
1436 * Private writable mapping: check memory availability
1437 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001438 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001439 charged = len >> PAGE_SHIFT;
Al Viro191c5422012-02-13 03:58:52 +00001440 if (security_vm_enough_memory_mm(mm, charged))
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001441 return -ENOMEM;
1442 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 }
1444
1445 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001446 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001448 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1449 if (vma)
1450 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451
1452 /*
1453 * Determine the object being mapped and call the appropriate
1454 * specific mapper. the address has already been validated, but
1455 * not unmapped, but the maps are removed from the list.
1456 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001457 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 if (!vma) {
1459 error = -ENOMEM;
1460 goto unacct_error;
1461 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
1463 vma->vm_mm = mm;
1464 vma->vm_start = addr;
1465 vma->vm_end = addr + len;
1466 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001467 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001469 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470
Hugh Dickinsce8fea72012-03-06 12:28:52 -08001471 error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */
1472
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1475 goto free_vma;
1476 if (vm_flags & VM_DENYWRITE) {
1477 error = deny_write_access(file);
1478 if (error)
1479 goto free_vma;
1480 correct_wcount = 1;
1481 }
Al Virocb0942b2012-08-27 14:48:26 -04001482 vma->vm_file = get_file(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 error = file->f_op->mmap(file, vma);
1484 if (error)
1485 goto unmap_and_free_vma;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001486
1487 /* Can addr have changed??
1488 *
1489 * Answer: Yes, several device drivers can do it in their
1490 * f_op->mmap method. -DaveM
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001491 * Bug: If addr is changed, prev, rb_link, rb_parent should
1492 * be updated for vma_link()
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001493 */
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001494 WARN_ON_ONCE(addr != vma->vm_start);
1495
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001496 addr = vma->vm_start;
1497 pgoff = vma->vm_pgoff;
1498 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499 } else if (vm_flags & VM_SHARED) {
Al Viro835ee792012-03-05 06:39:47 +00001500 if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP)))
1501 goto free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502 error = shmem_zero_setup(vma);
1503 if (error)
1504 goto free_vma;
1505 }
1506
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001507 if (vma_wants_writenotify(vma)) {
1508 pgprot_t pprot = vma->vm_page_prot;
1509
1510 /* Can vma->vm_page_prot have changed??
1511 *
1512 * Answer: Yes, drivers may have changed it in their
1513 * f_op->mmap method.
1514 *
1515 * Ensures that vmas marked as uncached stay that way.
1516 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001517 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001518 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1519 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1520 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001521
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001522 vma_link(mm, vma, prev, rb_link, rb_parent);
1523 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001524
1525 /* Once vma denies write, undo our temporary denial count */
1526 if (correct_wcount)
1527 atomic_inc(&inode->i_writecount);
1528out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001529 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001530
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001531 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001532 if (vm_flags & VM_LOCKED) {
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001533 if (!mlock_vma_pages_range(vma, addr, addr + len))
1534 mm->locked_vm += (len >> PAGE_SHIFT);
Rik van Rielba470de2008-10-18 20:26:50 -07001535 } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
Nick Piggin54cb8822007-07-19 01:46:59 -07001536 make_pages_present(addr, addr + len);
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301537
Oleg Nesterovc7a3a882012-08-19 19:10:42 +02001538 if (file)
1539 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301540
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 return addr;
1542
1543unmap_and_free_vma:
1544 if (correct_wcount)
1545 atomic_inc(&inode->i_writecount);
1546 vma->vm_file = NULL;
1547 fput(file);
1548
1549 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001550 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1551 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552free_vma:
1553 kmem_cache_free(vm_area_cachep, vma);
1554unacct_error:
1555 if (charged)
1556 vm_unacct_memory(charged);
1557 return error;
1558}
1559
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001560unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1561{
1562 /*
1563 * We implement the search by looking for an rbtree node that
1564 * immediately follows a suitable gap. That is,
1565 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1566 * - gap_end = vma->vm_start >= info->low_limit + length;
1567 * - gap_end - gap_start >= length
1568 */
1569
1570 struct mm_struct *mm = current->mm;
1571 struct vm_area_struct *vma;
1572 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1573
1574 /* Adjust search length to account for worst case alignment overhead */
1575 length = info->length + info->align_mask;
1576 if (length < info->length)
1577 return -ENOMEM;
1578
1579 /* Adjust search limits by the desired length */
1580 if (info->high_limit < length)
1581 return -ENOMEM;
1582 high_limit = info->high_limit - length;
1583
1584 if (info->low_limit > high_limit)
1585 return -ENOMEM;
1586 low_limit = info->low_limit + length;
1587
1588 /* Check if rbtree root looks promising */
1589 if (RB_EMPTY_ROOT(&mm->mm_rb))
1590 goto check_highest;
1591 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1592 if (vma->rb_subtree_gap < length)
1593 goto check_highest;
1594
1595 while (true) {
1596 /* Visit left subtree if it looks promising */
1597 gap_end = vma->vm_start;
1598 if (gap_end >= low_limit && vma->vm_rb.rb_left) {
1599 struct vm_area_struct *left =
1600 rb_entry(vma->vm_rb.rb_left,
1601 struct vm_area_struct, vm_rb);
1602 if (left->rb_subtree_gap >= length) {
1603 vma = left;
1604 continue;
1605 }
1606 }
1607
1608 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1609check_current:
1610 /* Check if current node has a suitable gap */
1611 if (gap_start > high_limit)
1612 return -ENOMEM;
1613 if (gap_end >= low_limit && gap_end - gap_start >= length)
1614 goto found;
1615
1616 /* Visit right subtree if it looks promising */
1617 if (vma->vm_rb.rb_right) {
1618 struct vm_area_struct *right =
1619 rb_entry(vma->vm_rb.rb_right,
1620 struct vm_area_struct, vm_rb);
1621 if (right->rb_subtree_gap >= length) {
1622 vma = right;
1623 continue;
1624 }
1625 }
1626
1627 /* Go back up the rbtree to find next candidate node */
1628 while (true) {
1629 struct rb_node *prev = &vma->vm_rb;
1630 if (!rb_parent(prev))
1631 goto check_highest;
1632 vma = rb_entry(rb_parent(prev),
1633 struct vm_area_struct, vm_rb);
1634 if (prev == vma->vm_rb.rb_left) {
1635 gap_start = vma->vm_prev->vm_end;
1636 gap_end = vma->vm_start;
1637 goto check_current;
1638 }
1639 }
1640 }
1641
1642check_highest:
1643 /* Check highest gap, which does not precede any rbtree node */
1644 gap_start = mm->highest_vm_end;
1645 gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
1646 if (gap_start > high_limit)
1647 return -ENOMEM;
1648
1649found:
1650 /* We found a suitable gap. Clip it with the original low_limit. */
1651 if (gap_start < info->low_limit)
1652 gap_start = info->low_limit;
1653
1654 /* Adjust gap address to the desired alignment */
1655 gap_start += (info->align_offset - gap_start) & info->align_mask;
1656
1657 VM_BUG_ON(gap_start + info->length > info->high_limit);
1658 VM_BUG_ON(gap_start + info->length > gap_end);
1659 return gap_start;
1660}
1661
1662unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1663{
1664 struct mm_struct *mm = current->mm;
1665 struct vm_area_struct *vma;
1666 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1667
1668 /* Adjust search length to account for worst case alignment overhead */
1669 length = info->length + info->align_mask;
1670 if (length < info->length)
1671 return -ENOMEM;
1672
1673 /*
1674 * Adjust search limits by the desired length.
1675 * See implementation comment at top of unmapped_area().
1676 */
1677 gap_end = info->high_limit;
1678 if (gap_end < length)
1679 return -ENOMEM;
1680 high_limit = gap_end - length;
1681
1682 if (info->low_limit > high_limit)
1683 return -ENOMEM;
1684 low_limit = info->low_limit + length;
1685
1686 /* Check highest gap, which does not precede any rbtree node */
1687 gap_start = mm->highest_vm_end;
1688 if (gap_start <= high_limit)
1689 goto found_highest;
1690
1691 /* Check if rbtree root looks promising */
1692 if (RB_EMPTY_ROOT(&mm->mm_rb))
1693 return -ENOMEM;
1694 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1695 if (vma->rb_subtree_gap < length)
1696 return -ENOMEM;
1697
1698 while (true) {
1699 /* Visit right subtree if it looks promising */
1700 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1701 if (gap_start <= high_limit && vma->vm_rb.rb_right) {
1702 struct vm_area_struct *right =
1703 rb_entry(vma->vm_rb.rb_right,
1704 struct vm_area_struct, vm_rb);
1705 if (right->rb_subtree_gap >= length) {
1706 vma = right;
1707 continue;
1708 }
1709 }
1710
1711check_current:
1712 /* Check if current node has a suitable gap */
1713 gap_end = vma->vm_start;
1714 if (gap_end < low_limit)
1715 return -ENOMEM;
1716 if (gap_start <= high_limit && gap_end - gap_start >= length)
1717 goto found;
1718
1719 /* Visit left subtree if it looks promising */
1720 if (vma->vm_rb.rb_left) {
1721 struct vm_area_struct *left =
1722 rb_entry(vma->vm_rb.rb_left,
1723 struct vm_area_struct, vm_rb);
1724 if (left->rb_subtree_gap >= length) {
1725 vma = left;
1726 continue;
1727 }
1728 }
1729
1730 /* Go back up the rbtree to find next candidate node */
1731 while (true) {
1732 struct rb_node *prev = &vma->vm_rb;
1733 if (!rb_parent(prev))
1734 return -ENOMEM;
1735 vma = rb_entry(rb_parent(prev),
1736 struct vm_area_struct, vm_rb);
1737 if (prev == vma->vm_rb.rb_right) {
1738 gap_start = vma->vm_prev ?
1739 vma->vm_prev->vm_end : 0;
1740 goto check_current;
1741 }
1742 }
1743 }
1744
1745found:
1746 /* We found a suitable gap. Clip it with the original high_limit. */
1747 if (gap_end > info->high_limit)
1748 gap_end = info->high_limit;
1749
1750found_highest:
1751 /* Compute highest gap address at the desired alignment */
1752 gap_end -= info->length;
1753 gap_end -= (gap_end - info->align_offset) & info->align_mask;
1754
1755 VM_BUG_ON(gap_end < info->low_limit);
1756 VM_BUG_ON(gap_end < gap_start);
1757 return gap_end;
1758}
1759
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760/* Get an address range which is currently unmapped.
1761 * For shmat() with addr=0.
1762 *
1763 * Ugly calling convention alert:
1764 * Return value with the low bits set means error value,
1765 * ie
1766 * if (ret & ~PAGE_MASK)
1767 * error = ret;
1768 *
1769 * This function "knows" that -ENOMEM has the bits set.
1770 */
1771#ifndef HAVE_ARCH_UNMAPPED_AREA
1772unsigned long
1773arch_get_unmapped_area(struct file *filp, unsigned long addr,
1774 unsigned long len, unsigned long pgoff, unsigned long flags)
1775{
1776 struct mm_struct *mm = current->mm;
1777 struct vm_area_struct *vma;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001778 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779
1780 if (len > TASK_SIZE)
1781 return -ENOMEM;
1782
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001783 if (flags & MAP_FIXED)
1784 return addr;
1785
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 if (addr) {
1787 addr = PAGE_ALIGN(addr);
1788 vma = find_vma(mm, addr);
1789 if (TASK_SIZE - len >= addr &&
1790 (!vma || addr + len <= vma->vm_start))
1791 return addr;
1792 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001793
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001794 info.flags = 0;
1795 info.length = len;
1796 info.low_limit = TASK_UNMAPPED_BASE;
1797 info.high_limit = TASK_SIZE;
1798 info.align_mask = 0;
1799 return vm_unmapped_area(&info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800}
1801#endif
1802
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001803void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804{
1805 /*
1806 * Is this a new hole at the lowest possible address?
1807 */
Xiao Guangrongf44d2192012-03-21 16:33:56 -07001808 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache)
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001809 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810}
1811
1812/*
1813 * This mmap-allocator allocates new areas top-down from below the
1814 * stack's low limit (the base):
1815 */
1816#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1817unsigned long
1818arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1819 const unsigned long len, const unsigned long pgoff,
1820 const unsigned long flags)
1821{
1822 struct vm_area_struct *vma;
1823 struct mm_struct *mm = current->mm;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001824 unsigned long addr = addr0;
1825 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826
1827 /* requested length too big for entire address space */
1828 if (len > TASK_SIZE)
1829 return -ENOMEM;
1830
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001831 if (flags & MAP_FIXED)
1832 return addr;
1833
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 /* requesting a specific address */
1835 if (addr) {
1836 addr = PAGE_ALIGN(addr);
1837 vma = find_vma(mm, addr);
1838 if (TASK_SIZE - len >= addr &&
1839 (!vma || addr + len <= vma->vm_start))
1840 return addr;
1841 }
1842
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001843 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
1844 info.length = len;
1845 info.low_limit = PAGE_SIZE;
1846 info.high_limit = mm->mmap_base;
1847 info.align_mask = 0;
1848 addr = vm_unmapped_area(&info);
Xiao Guangrongb716ad92012-03-21 16:33:56 -07001849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 /*
1851 * A failed mmap() very likely causes application failure,
1852 * so fall back to the bottom-up function here. This scenario
1853 * can happen with large stack limits and large mmap()
1854 * allocations.
1855 */
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001856 if (addr & ~PAGE_MASK) {
1857 VM_BUG_ON(addr != -ENOMEM);
1858 info.flags = 0;
1859 info.low_limit = TASK_UNMAPPED_BASE;
1860 info.high_limit = TASK_SIZE;
1861 addr = vm_unmapped_area(&info);
1862 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863
1864 return addr;
1865}
1866#endif
1867
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001868void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869{
1870 /*
1871 * Is this a new hole at the highest possible address?
1872 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001873 if (addr > mm->free_area_cache)
1874 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875
1876 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001877 if (mm->free_area_cache > mm->mmap_base)
1878 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879}
1880
1881unsigned long
1882get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1883 unsigned long pgoff, unsigned long flags)
1884{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001885 unsigned long (*get_area)(struct file *, unsigned long,
1886 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887
Al Viro9206de92009-12-03 15:23:11 -05001888 unsigned long error = arch_mmap_check(addr, len, flags);
1889 if (error)
1890 return error;
1891
1892 /* Careful about overflows.. */
1893 if (len > TASK_SIZE)
1894 return -ENOMEM;
1895
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001896 get_area = current->mm->get_unmapped_area;
1897 if (file && file->f_op && file->f_op->get_unmapped_area)
1898 get_area = file->f_op->get_unmapped_area;
1899 addr = get_area(file, addr, len, pgoff, flags);
1900 if (IS_ERR_VALUE(addr))
1901 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001903 if (addr > TASK_SIZE - len)
1904 return -ENOMEM;
1905 if (addr & ~PAGE_MASK)
1906 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001907
Al Viro9ac4ed42012-05-30 17:13:15 -04001908 addr = arch_rebalance_pgtables(addr, len);
1909 error = security_mmap_addr(addr);
1910 return error ? error : addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911}
1912
1913EXPORT_SYMBOL(get_unmapped_area);
1914
1915/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001916struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917{
1918 struct vm_area_struct *vma = NULL;
1919
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001920 if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */
1921 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001923 /* Check the cache first. */
1924 /* (Cache hit rate is typically around 35%.) */
1925 vma = mm->mmap_cache;
1926 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1927 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001929 rb_node = mm->mm_rb.rb_node;
1930 vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001932 while (rb_node) {
1933 struct vm_area_struct *vma_tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001935 vma_tmp = rb_entry(rb_node,
1936 struct vm_area_struct, vm_rb);
1937
1938 if (vma_tmp->vm_end > addr) {
1939 vma = vma_tmp;
1940 if (vma_tmp->vm_start <= addr)
1941 break;
1942 rb_node = rb_node->rb_left;
1943 } else
1944 rb_node = rb_node->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 }
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001946 if (vma)
1947 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 }
1949 return vma;
1950}
1951
1952EXPORT_SYMBOL(find_vma);
1953
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001954/*
1955 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001956 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957struct vm_area_struct *
1958find_vma_prev(struct mm_struct *mm, unsigned long addr,
1959 struct vm_area_struct **pprev)
1960{
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001961 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001963 vma = find_vma(mm, addr);
Mikulas Patocka83cd9042012-03-04 19:52:03 -05001964 if (vma) {
1965 *pprev = vma->vm_prev;
1966 } else {
1967 struct rb_node *rb_node = mm->mm_rb.rb_node;
1968 *pprev = NULL;
1969 while (rb_node) {
1970 *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1971 rb_node = rb_node->rb_right;
1972 }
1973 }
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001974 return vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975}
1976
1977/*
1978 * Verify that the stack growth is acceptable and
1979 * update accounting. This is shared with both the
1980 * grow-up and grow-down cases.
1981 */
ZhenwenXu48aae422009-01-06 14:40:21 -08001982static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983{
1984 struct mm_struct *mm = vma->vm_mm;
1985 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001986 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987
1988 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001989 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 return -ENOMEM;
1991
1992 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08001993 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 return -ENOMEM;
1995
1996 /* mlock limit tests */
1997 if (vma->vm_flags & VM_LOCKED) {
1998 unsigned long locked;
1999 unsigned long limit;
2000 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002001 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
2002 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 if (locked > limit && !capable(CAP_IPC_LOCK))
2004 return -ENOMEM;
2005 }
2006
Adam Litke0d59a012007-01-30 14:35:39 -08002007 /* Check to ensure the stack will not grow into a hugetlb-only region */
2008 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
2009 vma->vm_end - size;
2010 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
2011 return -EFAULT;
2012
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 /*
2014 * Overcommit.. This must be the final test, as it will
2015 * update security statistics.
2016 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01002017 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002018 return -ENOMEM;
2019
2020 /* Ok, everything looks good - let it rip */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021 if (vma->vm_flags & VM_LOCKED)
2022 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07002023 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024 return 0;
2025}
2026
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002027#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002029 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2030 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002031 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002032int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033{
2034 int error;
2035
2036 if (!(vma->vm_flags & VM_GROWSUP))
2037 return -EFAULT;
2038
2039 /*
2040 * We must make sure the anon_vma is allocated
2041 * so that the anon_vma locking is not a noop.
2042 */
2043 if (unlikely(anon_vma_prepare(vma)))
2044 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07002045 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046
2047 /*
2048 * vma->vm_start/vm_end cannot change under us because the caller
2049 * is required to hold the mmap_sem in read mode. We need the
2050 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01002051 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 */
Helge Deller06b32f32006-12-19 19:28:33 +01002053 if (address < PAGE_ALIGN(address+4))
2054 address = PAGE_ALIGN(address+4);
2055 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07002056 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01002057 return -ENOMEM;
2058 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002059 error = 0;
2060
2061 /* Somebody else might have raced and expanded it already */
2062 if (address > vma->vm_end) {
2063 unsigned long size, grow;
2064
2065 size = address - vma->vm_start;
2066 grow = (address - vma->vm_end) >> PAGE_SHIFT;
2067
Hugh Dickins42c36f62011-05-09 17:44:42 -07002068 error = -ENOMEM;
2069 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
2070 error = acct_stack_growth(vma, size, grow);
2071 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002072 /*
2073 * vma_gap_update() doesn't support concurrent
2074 * updates, but we only hold a shared mmap_sem
2075 * lock here, so we need to protect against
2076 * concurrent vma expansions.
2077 * vma_lock_anon_vma() doesn't help here, as
2078 * we don't guarantee that all growable vmas
2079 * in a mm share the same root anon vma.
2080 * So, we reuse mm->page_table_lock to guard
2081 * against concurrent vma expansions.
2082 */
2083 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002084 anon_vma_interval_tree_pre_update_vma(vma);
Hugh Dickins42c36f62011-05-09 17:44:42 -07002085 vma->vm_end = address;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002086 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002087 if (vma->vm_next)
2088 vma_gap_update(vma->vm_next);
2089 else
2090 vma->vm_mm->highest_vm_end = address;
Michel Lespinasse41289972012-12-12 13:52:25 -08002091 spin_unlock(&vma->vm_mm->page_table_lock);
2092
Hugh Dickins42c36f62011-05-09 17:44:42 -07002093 perf_event_mmap(vma);
2094 }
Eric B Munson3af9e852010-05-18 15:30:49 +01002095 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002097 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002098 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002099 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 return error;
2101}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002102#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2103
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104/*
2105 * vma is the first one with address < vma->vm_start. Have to extend vma.
2106 */
Michal Hockod05f3162011-05-24 17:11:44 -07002107int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002108 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109{
2110 int error;
2111
2112 /*
2113 * We must make sure the anon_vma is allocated
2114 * so that the anon_vma locking is not a noop.
2115 */
2116 if (unlikely(anon_vma_prepare(vma)))
2117 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05002118
2119 address &= PAGE_MASK;
Al Viroe5467852012-05-30 13:30:51 -04002120 error = security_mmap_addr(address);
Eric Paris88694772007-11-26 18:47:26 -05002121 if (error)
2122 return error;
2123
Rik van Rielbb4a3402010-08-09 17:18:37 -07002124 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125
2126 /*
2127 * vma->vm_start/vm_end cannot change under us because the caller
2128 * is required to hold the mmap_sem in read mode. We need the
2129 * anon_vma lock to serialize against concurrent expand_stacks.
2130 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131
2132 /* Somebody else might have raced and expanded it already */
2133 if (address < vma->vm_start) {
2134 unsigned long size, grow;
2135
2136 size = vma->vm_end - address;
2137 grow = (vma->vm_start - address) >> PAGE_SHIFT;
2138
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002139 error = -ENOMEM;
2140 if (grow <= vma->vm_pgoff) {
2141 error = acct_stack_growth(vma, size, grow);
2142 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002143 /*
2144 * vma_gap_update() doesn't support concurrent
2145 * updates, but we only hold a shared mmap_sem
2146 * lock here, so we need to protect against
2147 * concurrent vma expansions.
2148 * vma_lock_anon_vma() doesn't help here, as
2149 * we don't guarantee that all growable vmas
2150 * in a mm share the same root anon vma.
2151 * So, we reuse mm->page_table_lock to guard
2152 * against concurrent vma expansions.
2153 */
2154 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002155 anon_vma_interval_tree_pre_update_vma(vma);
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002156 vma->vm_start = address;
2157 vma->vm_pgoff -= grow;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002158 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002159 vma_gap_update(vma);
Michel Lespinasse41289972012-12-12 13:52:25 -08002160 spin_unlock(&vma->vm_mm->page_table_lock);
2161
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002162 perf_event_mmap(vma);
2163 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 }
2165 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002166 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002167 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002168 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 return error;
2170}
2171
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002172#ifdef CONFIG_STACK_GROWSUP
2173int expand_stack(struct vm_area_struct *vma, unsigned long address)
2174{
2175 return expand_upwards(vma, address);
2176}
2177
2178struct vm_area_struct *
2179find_extend_vma(struct mm_struct *mm, unsigned long addr)
2180{
2181 struct vm_area_struct *vma, *prev;
2182
2183 addr &= PAGE_MASK;
2184 vma = find_vma_prev(mm, addr, &prev);
2185 if (vma && (vma->vm_start <= addr))
2186 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01002187 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002188 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07002189 if (prev->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08002190 mlock_vma_pages_range(prev, addr, prev->vm_end);
Rik van Rielba470de2008-10-18 20:26:50 -07002191 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002192 return prev;
2193}
2194#else
2195int expand_stack(struct vm_area_struct *vma, unsigned long address)
2196{
2197 return expand_downwards(vma, address);
2198}
2199
Linus Torvalds1da177e2005-04-16 15:20:36 -07002200struct vm_area_struct *
2201find_extend_vma(struct mm_struct * mm, unsigned long addr)
2202{
2203 struct vm_area_struct * vma;
2204 unsigned long start;
2205
2206 addr &= PAGE_MASK;
2207 vma = find_vma(mm,addr);
2208 if (!vma)
2209 return NULL;
2210 if (vma->vm_start <= addr)
2211 return vma;
2212 if (!(vma->vm_flags & VM_GROWSDOWN))
2213 return NULL;
2214 start = vma->vm_start;
2215 if (expand_stack(vma, addr))
2216 return NULL;
Rik van Rielba470de2008-10-18 20:26:50 -07002217 if (vma->vm_flags & VM_LOCKED) {
KOSAKI Motohiroc58267c2010-03-05 13:41:43 -08002218 mlock_vma_pages_range(vma, addr, start);
Rik van Rielba470de2008-10-18 20:26:50 -07002219 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 return vma;
2221}
2222#endif
2223
Linus Torvalds1da177e2005-04-16 15:20:36 -07002224/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002225 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002227 *
2228 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002230static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231{
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002232 unsigned long nr_accounted = 0;
2233
Hugh Dickins365e9c872005-10-29 18:16:18 -07002234 /* Update high watermark before we lower total_vm */
2235 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002236 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002237 long nrpages = vma_pages(vma);
2238
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002239 if (vma->vm_flags & VM_ACCOUNT)
2240 nr_accounted += nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002241 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002242 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07002243 } while (vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002244 vm_unacct_memory(nr_accounted);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245 validate_mm(mm);
2246}
2247
2248/*
2249 * Get rid of page table information in the indicated region.
2250 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07002251 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252 */
2253static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07002254 struct vm_area_struct *vma, struct vm_area_struct *prev,
2255 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256{
Hugh Dickinse0da3822005-04-19 13:29:15 -07002257 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002258 struct mmu_gather tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259
2260 lru_add_drain();
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002261 tlb_gather_mmu(&tlb, mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002262 update_hiwater_rss(mm);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002263 unmap_vmas(&tlb, vma, start, end);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002264 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
2265 next ? next->vm_start : 0);
2266 tlb_finish_mmu(&tlb, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267}
2268
2269/*
2270 * Create a list of vma's touched by the unmap, removing them from the mm's
2271 * vma list as we go..
2272 */
2273static void
2274detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
2275 struct vm_area_struct *prev, unsigned long end)
2276{
2277 struct vm_area_struct **insertion_point;
2278 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07002279 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280
2281 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002282 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283 do {
Michel Lespinassed3737182012-12-11 16:01:38 -08002284 vma_rb_erase(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285 mm->map_count--;
2286 tail_vma = vma;
2287 vma = vma->vm_next;
2288 } while (vma && vma->vm_start < end);
2289 *insertion_point = vma;
Michel Lespinassed3737182012-12-11 16:01:38 -08002290 if (vma) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002291 vma->vm_prev = prev;
Michel Lespinassed3737182012-12-11 16:01:38 -08002292 vma_gap_update(vma);
2293 } else
2294 mm->highest_vm_end = prev ? prev->vm_end : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07002296 if (mm->unmap_area == arch_unmap_area)
2297 addr = prev ? prev->vm_end : mm->mmap_base;
2298 else
2299 addr = vma ? vma->vm_start : mm->mmap_base;
2300 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301 mm->mmap_cache = NULL; /* Kill the cache. */
2302}
2303
2304/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002305 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
2306 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002307 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002308static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002309 unsigned long addr, int new_below)
2310{
2311 struct mempolicy *pol;
2312 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08002313 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314
Andi Kleena5516432008-07-23 21:27:41 -07002315 if (is_vm_hugetlb_page(vma) && (addr &
2316 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317 return -EINVAL;
2318
Christoph Lametere94b1762006-12-06 20:33:17 -08002319 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08002321 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322
2323 /* most fields are the same, copy all, and then fixup */
2324 *new = *vma;
2325
Rik van Riel5beb4932010-03-05 13:42:07 -08002326 INIT_LIST_HEAD(&new->anon_vma_chain);
2327
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 if (new_below)
2329 new->vm_end = addr;
2330 else {
2331 new->vm_start = addr;
2332 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2333 }
2334
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002335 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 if (IS_ERR(pol)) {
Rik van Riel5beb4932010-03-05 13:42:07 -08002337 err = PTR_ERR(pol);
2338 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339 }
2340 vma_set_policy(new, pol);
2341
Rik van Riel5beb4932010-03-05 13:42:07 -08002342 if (anon_vma_clone(new, vma))
2343 goto out_free_mpol;
2344
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002345 if (new->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 get_file(new->vm_file);
2347
2348 if (new->vm_ops && new->vm_ops->open)
2349 new->vm_ops->open(new);
2350
2351 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08002352 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353 ((addr - new->vm_start) >> PAGE_SHIFT), new);
2354 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002355 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356
Rik van Riel5beb4932010-03-05 13:42:07 -08002357 /* Success. */
2358 if (!err)
2359 return 0;
2360
2361 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002362 if (new->vm_ops && new->vm_ops->close)
2363 new->vm_ops->close(new);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002364 if (new->vm_file)
Rik van Riel5beb4932010-03-05 13:42:07 -08002365 fput(new->vm_file);
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002366 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002367 out_free_mpol:
2368 mpol_put(pol);
2369 out_free_vma:
2370 kmem_cache_free(vm_area_cachep, new);
2371 out_err:
2372 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373}
2374
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002375/*
2376 * Split a vma into two pieces at address 'addr', a new vma is allocated
2377 * either for the first part or the tail.
2378 */
2379int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2380 unsigned long addr, int new_below)
2381{
2382 if (mm->map_count >= sysctl_max_map_count)
2383 return -ENOMEM;
2384
2385 return __split_vma(mm, vma, addr, new_below);
2386}
2387
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388/* Munmap is split into 2 main parts -- this part which finds
2389 * what needs doing, and the areas themselves, which do the
2390 * work. This now handles partial unmappings.
2391 * Jeremy Fitzhardinge <jeremy@goop.org>
2392 */
2393int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2394{
2395 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002396 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397
2398 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2399 return -EINVAL;
2400
2401 if ((len = PAGE_ALIGN(len)) == 0)
2402 return -EINVAL;
2403
2404 /* Find the first overlapping VMA */
Linus Torvalds9be34c92011-06-16 00:35:09 -07002405 vma = find_vma(mm, start);
Hugh Dickins146425a2005-04-19 13:29:18 -07002406 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 return 0;
Linus Torvalds9be34c92011-06-16 00:35:09 -07002408 prev = vma->vm_prev;
Hugh Dickins146425a2005-04-19 13:29:18 -07002409 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002410
2411 /* if it doesn't overlap, we have nothing.. */
2412 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002413 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414 return 0;
2415
2416 /*
2417 * If we need to split any vma, do it now to save pain later.
2418 *
2419 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2420 * unmapped vm_area_struct will remain in use: so lower split_vma
2421 * places tmp vma above, and higher split_vma places tmp vma below.
2422 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002423 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002424 int error;
2425
2426 /*
2427 * Make sure that map_count on return from munmap() will
2428 * not exceed its limit; but let map_count go just above
2429 * its limit temporarily, to help free resources as expected.
2430 */
2431 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2432 return -ENOMEM;
2433
2434 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002435 if (error)
2436 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002437 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002438 }
2439
2440 /* Does it split the last one? */
2441 last = find_vma(mm, end);
2442 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002443 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002444 if (error)
2445 return error;
2446 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002447 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002448
2449 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002450 * unlock any mlock()ed ranges before detaching vmas
2451 */
2452 if (mm->locked_vm) {
2453 struct vm_area_struct *tmp = vma;
2454 while (tmp && tmp->vm_start < end) {
2455 if (tmp->vm_flags & VM_LOCKED) {
2456 mm->locked_vm -= vma_pages(tmp);
2457 munlock_vma_pages_all(tmp);
2458 }
2459 tmp = tmp->vm_next;
2460 }
2461 }
2462
2463 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002464 * Remove the vma's, and unmap the actual pages
2465 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002466 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2467 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468
2469 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002470 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002471
2472 return 0;
2473}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002474
Al Virobfce2812012-04-20 21:57:04 -04002475int vm_munmap(unsigned long start, size_t len)
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002476{
2477 int ret;
Al Virobfce2812012-04-20 21:57:04 -04002478 struct mm_struct *mm = current->mm;
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002479
2480 down_write(&mm->mmap_sem);
2481 ret = do_munmap(mm, start, len);
2482 up_write(&mm->mmap_sem);
2483 return ret;
2484}
2485EXPORT_SYMBOL(vm_munmap);
2486
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002487SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002488{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002489 profile_munmap(addr);
Al Virobfce2812012-04-20 21:57:04 -04002490 return vm_munmap(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002491}
2492
2493static inline void verify_mm_writelocked(struct mm_struct *mm)
2494{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002495#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002496 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2497 WARN_ON(1);
2498 up_read(&mm->mmap_sem);
2499 }
2500#endif
2501}
2502
2503/*
2504 * this is really a simplified "do_mmap". it only handles
2505 * anonymous maps. eventually we may be able to do some
2506 * brk-specific accounting here.
2507 */
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002508static unsigned long do_brk(unsigned long addr, unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509{
2510 struct mm_struct * mm = current->mm;
2511 struct vm_area_struct * vma, * prev;
2512 unsigned long flags;
2513 struct rb_node ** rb_link, * rb_parent;
2514 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002515 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002516
2517 len = PAGE_ALIGN(len);
2518 if (!len)
2519 return addr;
2520
Kirill Korotaev3a459752006-09-07 14:17:04 +04002521 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2522
Al Viro2c6a1012009-12-03 19:40:46 -05002523 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2524 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002525 return error;
2526
Linus Torvalds1da177e2005-04-16 15:20:36 -07002527 /*
2528 * mlock MCL_FUTURE?
2529 */
2530 if (mm->def_flags & VM_LOCKED) {
2531 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002532 locked = len >> PAGE_SHIFT;
2533 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002534 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002535 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002536 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2537 return -EAGAIN;
2538 }
2539
2540 /*
2541 * mm->mmap_sem is required to protect against another thread
2542 * changing the mappings in case we sleep.
2543 */
2544 verify_mm_writelocked(mm);
2545
2546 /*
2547 * Clear old maps. this also does some error checking for us
2548 */
2549 munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07002550 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002551 if (do_munmap(mm, addr, len))
2552 return -ENOMEM;
2553 goto munmap_back;
2554 }
2555
2556 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002557 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002558 return -ENOMEM;
2559
2560 if (mm->map_count > sysctl_max_map_count)
2561 return -ENOMEM;
2562
Al Viro191c5422012-02-13 03:58:52 +00002563 if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002564 return -ENOMEM;
2565
Linus Torvalds1da177e2005-04-16 15:20:36 -07002566 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002567 vma = vma_merge(mm, prev, addr, addr + len, flags,
2568 NULL, NULL, pgoff, NULL);
2569 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002570 goto out;
2571
2572 /*
2573 * create a vma struct for an anonymous mapping
2574 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002575 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002576 if (!vma) {
2577 vm_unacct_memory(len >> PAGE_SHIFT);
2578 return -ENOMEM;
2579 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002580
Rik van Riel5beb4932010-03-05 13:42:07 -08002581 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582 vma->vm_mm = mm;
2583 vma->vm_start = addr;
2584 vma->vm_end = addr + len;
2585 vma->vm_pgoff = pgoff;
2586 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002587 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002588 vma_link(mm, vma, prev, rb_link, rb_parent);
2589out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002590 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002591 mm->total_vm += len >> PAGE_SHIFT;
2592 if (flags & VM_LOCKED) {
Rik van Rielba470de2008-10-18 20:26:50 -07002593 if (!mlock_vma_pages_range(vma, addr, addr + len))
2594 mm->locked_vm += (len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002595 }
2596 return addr;
2597}
2598
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002599unsigned long vm_brk(unsigned long addr, unsigned long len)
2600{
2601 struct mm_struct *mm = current->mm;
2602 unsigned long ret;
2603
2604 down_write(&mm->mmap_sem);
2605 ret = do_brk(addr, len);
2606 up_write(&mm->mmap_sem);
2607 return ret;
2608}
2609EXPORT_SYMBOL(vm_brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610
2611/* Release all mmaps. */
2612void exit_mmap(struct mm_struct *mm)
2613{
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002614 struct mmu_gather tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002615 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002616 unsigned long nr_accounted = 0;
2617
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002618 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002619 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002620
Rik van Rielba470de2008-10-18 20:26:50 -07002621 if (mm->locked_vm) {
2622 vma = mm->mmap;
2623 while (vma) {
2624 if (vma->vm_flags & VM_LOCKED)
2625 munlock_vma_pages_all(vma);
2626 vma = vma->vm_next;
2627 }
2628 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002629
2630 arch_exit_mmap(mm);
2631
Rik van Rielba470de2008-10-18 20:26:50 -07002632 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002633 if (!vma) /* Can happen if dup_mmap() received an OOM */
2634 return;
2635
Linus Torvalds1da177e2005-04-16 15:20:36 -07002636 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002637 flush_cache_mm(mm);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002638 tlb_gather_mmu(&tlb, mm, 1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002639 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002640 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002641 unmap_vmas(&tlb, vma, 0, -1);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002642
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002643 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Al Viro853f5e22012-03-05 14:03:47 -05002644 tlb_finish_mmu(&tlb, 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002645
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002647 * Walk the list again, actually closing and freeing it,
2648 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002650 while (vma) {
2651 if (vma->vm_flags & VM_ACCOUNT)
2652 nr_accounted += vma_pages(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002653 vma = remove_vma(vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002654 }
2655 vm_unacct_memory(nr_accounted);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002656
Hugh Dickinsf9aed622012-08-21 16:15:45 -07002657 WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002658}
2659
2660/* Insert vm structure into process list sorted by address
2661 * and into the inode's i_mmap tree. If vm_file is non-NULL
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002662 * then i_mmap_mutex is taken here.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002663 */
Hugh Dickins6597d782012-10-08 16:29:07 -07002664int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002665{
Hugh Dickins6597d782012-10-08 16:29:07 -07002666 struct vm_area_struct *prev;
2667 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002668
2669 /*
2670 * The vm_pgoff of a purely anonymous vma should be irrelevant
2671 * until its first write fault, when page's anon_vma and index
2672 * are set. But now set the vm_pgoff it will almost certainly
2673 * end up with (unless mremap moves it elsewhere before that
2674 * first wfault), so /proc/pid/maps tells a consistent story.
2675 *
2676 * By setting it to reflect the virtual start address of the
2677 * vma, merges and splits can happen in a seamless way, just
2678 * using the existing file pgoff checks and manipulations.
2679 * Similarly in do_mmap_pgoff and in do_brk.
2680 */
2681 if (!vma->vm_file) {
2682 BUG_ON(vma->anon_vma);
2683 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2684 }
Hugh Dickins6597d782012-10-08 16:29:07 -07002685 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
2686 &prev, &rb_link, &rb_parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002687 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002688 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002689 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002690 return -ENOMEM;
Srikar Dronamraju2b144492012-02-09 14:56:42 +05302691
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 vma_link(mm, vma, prev, rb_link, rb_parent);
2693 return 0;
2694}
2695
2696/*
2697 * Copy the vma structure to a new location in the same mm,
2698 * prior to moving page table entries, to effect an mremap move.
2699 */
2700struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
Michel Lespinasse38a76012012-10-08 16:31:50 -07002701 unsigned long addr, unsigned long len, pgoff_t pgoff,
2702 bool *need_rmap_locks)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002703{
2704 struct vm_area_struct *vma = *vmap;
2705 unsigned long vma_start = vma->vm_start;
2706 struct mm_struct *mm = vma->vm_mm;
2707 struct vm_area_struct *new_vma, *prev;
2708 struct rb_node **rb_link, *rb_parent;
2709 struct mempolicy *pol;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002710 bool faulted_in_anon_vma = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002711
2712 /*
2713 * If anonymous vma has not yet been faulted, update new pgoff
2714 * to match new location, to increase its chance of merging.
2715 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002716 if (unlikely(!vma->vm_file && !vma->anon_vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002717 pgoff = addr >> PAGE_SHIFT;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002718 faulted_in_anon_vma = false;
2719 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002720
Hugh Dickins6597d782012-10-08 16:29:07 -07002721 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
2722 return NULL; /* should never get here */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002723 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2724 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2725 if (new_vma) {
2726 /*
2727 * Source vma may have been merged into new_vma
2728 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002729 if (unlikely(vma_start >= new_vma->vm_start &&
2730 vma_start < new_vma->vm_end)) {
2731 /*
2732 * The only way we can get a vma_merge with
2733 * self during an mremap is if the vma hasn't
2734 * been faulted in yet and we were allowed to
2735 * reset the dst vma->vm_pgoff to the
2736 * destination address of the mremap to allow
2737 * the merge to happen. mremap must change the
2738 * vm_pgoff linearity between src and dst vmas
2739 * (in turn preventing a vma_merge) to be
2740 * safe. It is only safe to keep the vm_pgoff
2741 * linear if there are no pages mapped yet.
2742 */
2743 VM_BUG_ON(faulted_in_anon_vma);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002744 *vmap = vma = new_vma;
Michel Lespinasse108d6642012-10-08 16:31:36 -07002745 }
Michel Lespinasse38a76012012-10-08 16:31:50 -07002746 *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002747 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002748 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002749 if (new_vma) {
2750 *new_vma = *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002751 new_vma->vm_start = addr;
2752 new_vma->vm_end = addr + len;
2753 new_vma->vm_pgoff = pgoff;
Michel Lespinasse523d4e22012-10-08 16:31:48 -07002754 pol = mpol_dup(vma_policy(vma));
2755 if (IS_ERR(pol))
2756 goto out_free_vma;
2757 vma_set_policy(new_vma, pol);
2758 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2759 if (anon_vma_clone(new_vma, vma))
2760 goto out_free_mempol;
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002761 if (new_vma->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002762 get_file(new_vma->vm_file);
2763 if (new_vma->vm_ops && new_vma->vm_ops->open)
2764 new_vma->vm_ops->open(new_vma);
2765 vma_link(mm, new_vma, prev, rb_link, rb_parent);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002766 *need_rmap_locks = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002767 }
2768 }
2769 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002770
2771 out_free_mempol:
2772 mpol_put(pol);
2773 out_free_vma:
2774 kmem_cache_free(vm_area_cachep, new_vma);
2775 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002776}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002777
2778/*
2779 * Return true if the calling process may expand its vm space by the passed
2780 * number of pages
2781 */
2782int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2783{
2784 unsigned long cur = mm->total_vm; /* pages */
2785 unsigned long lim;
2786
Jiri Slaby59e99e52010-03-05 13:41:44 -08002787 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002788
2789 if (cur + npages > lim)
2790 return 0;
2791 return 1;
2792}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002793
2794
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002795static int special_mapping_fault(struct vm_area_struct *vma,
2796 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002797{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002798 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002799 struct page **pages;
2800
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002801 /*
2802 * special mappings have no vm_file, and in that case, the mm
2803 * uses vm_pgoff internally. So we have to subtract it from here.
2804 * We are allowed to do this because we are the mm; do not copy
2805 * this code into drivers!
2806 */
2807 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002808
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002809 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2810 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002811
2812 if (*pages) {
2813 struct page *page = *pages;
2814 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002815 vmf->page = page;
2816 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002817 }
2818
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002819 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002820}
2821
2822/*
2823 * Having a close hook prevents vma merging regardless of flags.
2824 */
2825static void special_mapping_close(struct vm_area_struct *vma)
2826{
2827}
2828
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002829static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002830 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002831 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002832};
2833
2834/*
2835 * Called with mm->mmap_sem held for writing.
2836 * Insert a new vma covering the given region, with the given flags.
2837 * Its pages are supplied by the given array of struct page *.
2838 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2839 * The region past the last page supplied will always produce SIGBUS.
2840 * The array pointer and the pages it points to are assumed to stay alive
2841 * for as long as this mapping might exist.
2842 */
2843int install_special_mapping(struct mm_struct *mm,
2844 unsigned long addr, unsigned long len,
2845 unsigned long vm_flags, struct page **pages)
2846{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002847 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002848 struct vm_area_struct *vma;
2849
2850 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2851 if (unlikely(vma == NULL))
2852 return -ENOMEM;
2853
Rik van Riel5beb4932010-03-05 13:42:07 -08002854 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002855 vma->vm_mm = mm;
2856 vma->vm_start = addr;
2857 vma->vm_end = addr + len;
2858
Nick Piggin2f987352008-02-02 03:08:53 +01002859 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002860 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002861
2862 vma->vm_ops = &special_mapping_vmops;
2863 vma->vm_private_data = pages;
2864
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002865 ret = insert_vm_struct(mm, vma);
2866 if (ret)
2867 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002868
2869 mm->total_vm += len >> PAGE_SHIFT;
2870
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002871 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002872
Roland McGrathfa5dc222007-02-08 14:20:41 -08002873 return 0;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002874
2875out:
2876 kmem_cache_free(vm_area_cachep, vma);
2877 return ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002878}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002879
2880static DEFINE_MUTEX(mm_all_locks_mutex);
2881
Peter Zijlstra454ed842008-08-11 09:30:25 +02002882static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002883{
Michel Lespinassebf181b92012-10-08 16:31:39 -07002884 if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002885 /*
2886 * The LSB of head.next can't change from under us
2887 * because we hold the mm_all_locks_mutex.
2888 */
Ingo Molnar5a505082012-12-02 19:56:46 +00002889 down_write(&anon_vma->root->rwsem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002890 /*
2891 * We can safely modify head.next after taking the
Ingo Molnar5a505082012-12-02 19:56:46 +00002892 * anon_vma->root->rwsem. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002893 * the same anon_vma we won't take it again.
2894 *
2895 * No need of atomic instructions here, head.next
2896 * can't change from under us thanks to the
Ingo Molnar5a505082012-12-02 19:56:46 +00002897 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002898 */
2899 if (__test_and_set_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07002900 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002901 BUG();
2902 }
2903}
2904
Peter Zijlstra454ed842008-08-11 09:30:25 +02002905static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002906{
2907 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2908 /*
2909 * AS_MM_ALL_LOCKS can't change from under us because
2910 * we hold the mm_all_locks_mutex.
2911 *
2912 * Operations on ->flags have to be atomic because
2913 * even if AS_MM_ALL_LOCKS is stable thanks to the
2914 * mm_all_locks_mutex, there may be other cpus
2915 * changing other bitflags in parallel to us.
2916 */
2917 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2918 BUG();
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002919 mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002920 }
2921}
2922
2923/*
2924 * This operation locks against the VM for all pte/vma/mm related
2925 * operations that could ever happen on a certain mm. This includes
2926 * vmtruncate, try_to_unmap, and all page faults.
2927 *
2928 * The caller must take the mmap_sem in write mode before calling
2929 * mm_take_all_locks(). The caller isn't allowed to release the
2930 * mmap_sem until mm_drop_all_locks() returns.
2931 *
2932 * mmap_sem in write mode is required in order to block all operations
2933 * that could modify pagetables and free pages without need of
2934 * altering the vma layout (for example populate_range() with
2935 * nonlinear vmas). It's also needed in write mode to avoid new
2936 * anon_vmas to be associated with existing vmas.
2937 *
2938 * A single task can't take more than one mm_take_all_locks() in a row
2939 * or it would deadlock.
2940 *
Michel Lespinassebf181b92012-10-08 16:31:39 -07002941 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002942 * mapping->flags avoid to take the same lock twice, if more than one
2943 * vma in this mm is backed by the same anon_vma or address_space.
2944 *
2945 * We can take all the locks in random order because the VM code
Peter Zijlstra2b575eb2011-05-24 17:12:11 -07002946 * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002947 * takes more than one of them in a row. Secondly we're protected
2948 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2949 *
2950 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2951 * that may have to take thousand of locks.
2952 *
2953 * mm_take_all_locks() can fail if it's interrupted by signals.
2954 */
2955int mm_take_all_locks(struct mm_struct *mm)
2956{
2957 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002958 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002959
2960 BUG_ON(down_read_trylock(&mm->mmap_sem));
2961
2962 mutex_lock(&mm_all_locks_mutex);
2963
2964 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2965 if (signal_pending(current))
2966 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002967 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02002968 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002969 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002970
2971 for (vma = mm->mmap; vma; vma = vma->vm_next) {
2972 if (signal_pending(current))
2973 goto out_unlock;
2974 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08002975 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
2976 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02002977 }
2978
Kautuk Consul584cff52011-10-31 17:08:59 -07002979 return 0;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002980
2981out_unlock:
Kautuk Consul584cff52011-10-31 17:08:59 -07002982 mm_drop_all_locks(mm);
2983 return -EINTR;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002984}
2985
2986static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
2987{
Michel Lespinassebf181b92012-10-08 16:31:39 -07002988 if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002989 /*
2990 * The LSB of head.next can't change to 0 from under
2991 * us because we hold the mm_all_locks_mutex.
2992 *
2993 * We must however clear the bitflag before unlocking
Michel Lespinassebf181b92012-10-08 16:31:39 -07002994 * the vma so the users using the anon_vma->rb_root will
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002995 * never see our bitflag.
2996 *
2997 * No need of atomic instructions here, head.next
2998 * can't change from under us until we release the
Ingo Molnar5a505082012-12-02 19:56:46 +00002999 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003000 */
3001 if (!__test_and_clear_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07003002 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003003 BUG();
Rik van Rielcba48b92010-08-09 17:18:38 -07003004 anon_vma_unlock(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003005 }
3006}
3007
3008static void vm_unlock_mapping(struct address_space *mapping)
3009{
3010 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3011 /*
3012 * AS_MM_ALL_LOCKS can't change to 0 from under us
3013 * because we hold the mm_all_locks_mutex.
3014 */
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07003015 mutex_unlock(&mapping->i_mmap_mutex);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003016 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3017 &mapping->flags))
3018 BUG();
3019 }
3020}
3021
3022/*
3023 * The mmap_sem cannot be released by the caller until
3024 * mm_drop_all_locks() returns.
3025 */
3026void mm_drop_all_locks(struct mm_struct *mm)
3027{
3028 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003029 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003030
3031 BUG_ON(down_read_trylock(&mm->mmap_sem));
3032 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3033
3034 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3035 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003036 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3037 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003038 if (vma->vm_file && vma->vm_file->f_mapping)
3039 vm_unlock_mapping(vma->vm_file->f_mapping);
3040 }
3041
3042 mutex_unlock(&mm_all_locks_mutex);
3043}
David Howells8feae132009-01-08 12:04:47 +00003044
3045/*
3046 * initialise the VMA slab
3047 */
3048void __init mmap_init(void)
3049{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07003050 int ret;
3051
3052 ret = percpu_counter_init(&vm_committed_as, 0);
3053 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00003054}