blob: 834b2d785f1e2f2fdce59a608f28a94b02b5d82d [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
Cyril Hrubise8420a82013-04-29 15:08:33 -07009#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070011#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/mm.h>
13#include <linux/shm.h>
14#include <linux/mman.h>
15#include <linux/pagemap.h>
16#include <linux/swap.h>
17#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080018#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/init.h>
20#include <linux/file.h>
21#include <linux/fs.h>
22#include <linux/personality.h>
23#include <linux/security.h>
24#include <linux/hugetlb.h>
25#include <linux/profile.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040026#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/mount.h>
28#include <linux/mempolicy.h>
29#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070030#include <linux/mmu_notifier.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020031#include <linux/perf_event.h>
Al Viro120a7952010-10-30 02:54:44 -040032#include <linux/audit.h>
Andrea Arcangelib15d00b2011-01-13 15:46:59 -080033#include <linux/khugepaged.h>
Srikar Dronamraju2b144492012-02-09 14:56:42 +053034#include <linux/uprobes.h>
Michel Lespinassed3737182012-12-11 16:01:38 -080035#include <linux/rbtree_augmented.h>
Clark Williamscf4aebc22013-02-07 09:46:59 -060036#include <linux/sched/sysctl.h>
Andrew Shewmaker16408792013-04-29 15:08:12 -070037#include <linux/notifier.h>
38#include <linux/memory.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
40#include <asm/uaccess.h>
41#include <asm/cacheflush.h>
42#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020043#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
Jan Beulich42b77722008-07-23 21:27:10 -070045#include "internal.h"
46
Kirill Korotaev3a459752006-09-07 14:17:04 +040047#ifndef arch_mmap_check
48#define arch_mmap_check(addr, len, flags) (0)
49#endif
50
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080051#ifndef arch_rebalance_pgtables
52#define arch_rebalance_pgtables(addr, len) (addr)
53#endif
54
Hugh Dickinse0da3822005-04-19 13:29:15 -070055static void unmap_region(struct mm_struct *mm,
56 struct vm_area_struct *vma, struct vm_area_struct *prev,
57 unsigned long start, unsigned long end);
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059/* description of effects of mapping type and prot in current implementation.
60 * this is due to the limited x86 page protection hardware. The expected
61 * behavior is in parens:
62 *
63 * map_type prot
64 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
65 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
66 * w: (no) no w: (no) no w: (yes) yes w: (no) no
67 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 *
69 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
70 * w: (no) no w: (no) no w: (copy) copy w: (no) no
71 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
72 *
73 */
74pgprot_t protection_map[16] = {
75 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
76 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
77};
78
Hugh Dickins804af2c2006-07-26 21:39:49 +010079pgprot_t vm_get_page_prot(unsigned long vm_flags)
80{
Dave Kleikampb845f312008-07-08 00:28:51 +100081 return __pgprot(pgprot_val(protection_map[vm_flags &
82 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
83 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010084}
85EXPORT_SYMBOL(vm_get_page_prot);
86
Shaohua Li34679d72011-05-24 17:11:18 -070087int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
88int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070089int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -070090unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -070091unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
Shaohua Li34679d72011-05-24 17:11:18 -070092/*
93 * Make sure vm_committed_as in one cacheline and not cacheline shared with
94 * other variables. It can be updated by several CPUs frequently.
95 */
96struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98/*
K. Y. Srinivasan997071b2012-11-15 14:34:42 -080099 * The global memory commitment made in the system can be a metric
100 * that can be used to drive ballooning decisions when Linux is hosted
101 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
102 * balancing memory across competing virtual machines that are hosted.
103 * Several metrics drive this policy engine including the guest reported
104 * memory commitment.
105 */
106unsigned long vm_memory_committed(void)
107{
108 return percpu_counter_read_positive(&vm_committed_as);
109}
110EXPORT_SYMBOL_GPL(vm_memory_committed);
111
112/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 * Check that a process has enough memory to allocate a new virtual
114 * mapping. 0 means there is enough memory for the allocation to
115 * succeed and -ENOMEM implies there is not.
116 *
117 * We currently support three overcommit policies, which are set via the
118 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
119 *
120 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
121 * Additional code 2002 Jul 20 by Robert Love.
122 *
123 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
124 *
125 * Note this is a helper function intended to be used by LSMs which
126 * wish to use this logic.
127 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700128int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129{
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -0700130 unsigned long free, allowed, reserve;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132 vm_acct_memory(pages);
133
134 /*
135 * Sometimes we want to use more memory than we have
136 */
137 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
138 return 0;
139
140 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -0700141 free = global_page_state(NR_FREE_PAGES);
142 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Dmitry Finkc15bef32011-07-25 17:12:19 -0700144 /*
145 * shmem pages shouldn't be counted as free in this
146 * case, they can't be purged, only swapped out, and
147 * that won't affect the overall amount of available
148 * memory in the system.
149 */
150 free -= global_page_state(NR_SHMEM);
151
Shaohua Liec8acf22013-02-22 16:34:38 -0800152 free += get_nr_swap_pages();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 /*
155 * Any slabs which are created with the
156 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
157 * which are reclaimable, under pressure. The dentry
158 * cache and most inode caches should fall into this
159 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700160 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
162 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -0700163 * Leave reserved pages. The pages are not for anonymous pages.
164 */
165 if (free <= totalreserve_pages)
166 goto error;
167 else
168 free -= totalreserve_pages;
169
170 /*
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -0700171 * Reserve some for root
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 */
173 if (!cap_sys_admin)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -0700174 free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 if (free > pages)
177 return 0;
178
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700179 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
181
Jerome Marchand00619bc2013-11-12 15:08:31 -0800182 allowed = vm_commit_limit();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 /*
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -0700184 * Reserve some for root
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 */
186 if (!cap_sys_admin)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -0700187 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -0700189 /*
190 * Don't let a single process grow so big a user can't recover
191 */
192 if (mm) {
193 reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
194 allowed -= min(mm->total_vm / 32, reserve);
195 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700197 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700199error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 vm_unacct_memory(pages);
201
202 return -ENOMEM;
203}
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205/*
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700206 * Requires inode->i_mapping->i_mmap_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 */
208static void __remove_shared_vm_struct(struct vm_area_struct *vma,
209 struct file *file, struct address_space *mapping)
210{
211 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500212 atomic_inc(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 if (vma->vm_flags & VM_SHARED)
214 mapping->i_mmap_writable--;
215
216 flush_dcache_mmap_lock(mapping);
217 if (unlikely(vma->vm_flags & VM_NONLINEAR))
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700218 list_del_init(&vma->shared.nonlinear);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700220 vma_interval_tree_remove(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 flush_dcache_mmap_unlock(mapping);
222}
223
224/*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700225 * Unlink a file-based vm structure from its interval tree, to hide
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700226 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700228void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229{
230 struct file *file = vma->vm_file;
231
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 if (file) {
233 struct address_space *mapping = file->f_mapping;
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700234 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 __remove_shared_vm_struct(vma, file, mapping);
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700236 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700238}
239
240/*
241 * Close a vm structure and free it, returning the next.
242 */
243static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
244{
245 struct vm_area_struct *next = vma->vm_next;
246
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700247 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 if (vma->vm_ops && vma->vm_ops->close)
249 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700250 if (vma->vm_file)
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700251 fput(vma->vm_file);
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700252 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700254 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255}
256
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -0700257static unsigned long do_brk(unsigned long addr, unsigned long len);
258
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100259SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260{
261 unsigned long rlim, retval;
262 unsigned long newbrk, oldbrk;
263 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700264 unsigned long min_brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800265 bool populate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
267 down_write(&mm->mmap_sem);
268
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700269#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800270 /*
271 * CONFIG_COMPAT_BRK can still be overridden by setting
272 * randomize_va_space to 2, which will still cause mm->start_brk
273 * to be arbitrarily shifted
274 */
Jiri Kosina4471a672011-04-14 15:22:09 -0700275 if (current->brk_randomized)
Jiri Kosina5520e892011-01-13 15:47:23 -0800276 min_brk = mm->start_brk;
277 else
278 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700279#else
280 min_brk = mm->start_brk;
281#endif
282 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700284
285 /*
286 * Check against rlimit here. If this check is done later after the test
287 * of oldbrk with newbrk then it can escape the test and let the data
288 * segment grow beyond its set limit the in case where the limit is
289 * not page aligned -Ram Gupta
290 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800291 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100292 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
293 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700294 goto out;
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 newbrk = PAGE_ALIGN(brk);
297 oldbrk = PAGE_ALIGN(mm->brk);
298 if (oldbrk == newbrk)
299 goto set_brk;
300
301 /* Always allow shrinking brk. */
302 if (brk <= mm->brk) {
303 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
304 goto set_brk;
305 goto out;
306 }
307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 /* Check against existing mmap mappings. */
309 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
310 goto out;
311
312 /* Ok, looks good - let it rip. */
313 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
314 goto out;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800315
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316set_brk:
317 mm->brk = brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800318 populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
319 up_write(&mm->mmap_sem);
320 if (populate)
321 mm_populate(oldbrk, newbrk - oldbrk);
322 return brk;
323
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324out:
325 retval = mm->brk;
326 up_write(&mm->mmap_sem);
327 return retval;
328}
329
Michel Lespinassed3737182012-12-11 16:01:38 -0800330static long vma_compute_subtree_gap(struct vm_area_struct *vma)
331{
332 unsigned long max, subtree_gap;
333 max = vma->vm_start;
334 if (vma->vm_prev)
335 max -= vma->vm_prev->vm_end;
336 if (vma->vm_rb.rb_left) {
337 subtree_gap = rb_entry(vma->vm_rb.rb_left,
338 struct vm_area_struct, vm_rb)->rb_subtree_gap;
339 if (subtree_gap > max)
340 max = subtree_gap;
341 }
342 if (vma->vm_rb.rb_right) {
343 subtree_gap = rb_entry(vma->vm_rb.rb_right,
344 struct vm_area_struct, vm_rb)->rb_subtree_gap;
345 if (subtree_gap > max)
346 max = subtree_gap;
347 }
348 return max;
349}
350
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700351#ifdef CONFIG_DEBUG_VM_RB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352static int browse_rb(struct rb_root *root)
353{
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800354 int i = 0, j, bug = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 struct rb_node *nd, *pn = NULL;
356 unsigned long prev = 0, pend = 0;
357
358 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
359 struct vm_area_struct *vma;
360 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800361 if (vma->vm_start < prev) {
362 printk("vm_start %lx prev %lx\n", vma->vm_start, prev);
363 bug = 1;
364 }
365 if (vma->vm_start < pend) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800367 bug = 1;
368 }
369 if (vma->vm_start > vma->vm_end) {
370 printk("vm_end %lx < vm_start %lx\n",
371 vma->vm_end, vma->vm_start);
372 bug = 1;
373 }
374 if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
375 printk("free gap %lx, correct %lx\n",
376 vma->rb_subtree_gap,
377 vma_compute_subtree_gap(vma));
378 bug = 1;
379 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 i++;
381 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800382 prev = vma->vm_start;
383 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
385 j = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800386 for (nd = pn; nd; nd = rb_prev(nd))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 j++;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800388 if (i != j) {
389 printk("backwards %d, forwards %d\n", j, i);
390 bug = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800392 return bug ? -1 : i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393}
394
Michel Lespinassed3737182012-12-11 16:01:38 -0800395static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
396{
397 struct rb_node *nd;
398
399 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
400 struct vm_area_struct *vma;
401 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
402 BUG_ON(vma != ignore &&
403 vma->rb_subtree_gap != vma_compute_subtree_gap(vma));
404 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405}
406
407void validate_mm(struct mm_struct *mm)
408{
409 int bug = 0;
410 int i = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800411 unsigned long highest_address = 0;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700412 struct vm_area_struct *vma = mm->mmap;
413 while (vma) {
414 struct anon_vma_chain *avc;
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800415 vma_lock_anon_vma(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700416 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
417 anon_vma_interval_tree_verify(avc);
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800418 vma_unlock_anon_vma(vma);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800419 highest_address = vma->vm_end;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700420 vma = vma->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 i++;
422 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800423 if (i != mm->map_count) {
424 printk("map_count %d vm_next %d\n", mm->map_count, i);
425 bug = 1;
426 }
427 if (highest_address != mm->highest_vm_end) {
428 printk("mm->highest_vm_end %lx, found %lx\n",
429 mm->highest_vm_end, highest_address);
430 bug = 1;
431 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 i = browse_rb(&mm->mm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800433 if (i != mm->map_count) {
434 printk("map_count %d rb %d\n", mm->map_count, i);
435 bug = 1;
436 }
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200437 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438}
439#else
Michel Lespinassed3737182012-12-11 16:01:38 -0800440#define validate_mm_rb(root, ignore) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441#define validate_mm(mm) do { } while (0)
442#endif
443
Michel Lespinassed3737182012-12-11 16:01:38 -0800444RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb,
445 unsigned long, rb_subtree_gap, vma_compute_subtree_gap)
446
447/*
448 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
449 * vma->vm_prev->vm_end values changed, without modifying the vma's position
450 * in the rbtree.
451 */
452static void vma_gap_update(struct vm_area_struct *vma)
453{
454 /*
455 * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
456 * function that does exacltly what we want.
457 */
458 vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
459}
460
461static inline void vma_rb_insert(struct vm_area_struct *vma,
462 struct rb_root *root)
463{
464 /* All rb_subtree_gap values must be consistent prior to insertion */
465 validate_mm_rb(root, NULL);
466
467 rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
468}
469
470static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
471{
472 /*
473 * All rb_subtree_gap values must be consistent prior to erase,
474 * with the possible exception of the vma being erased.
475 */
476 validate_mm_rb(root, vma);
477
478 /*
479 * Note rb_erase_augmented is a fairly large inline function,
480 * so make sure we instantiate it only once with our desired
481 * augmented rbtree callbacks.
482 */
483 rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
484}
485
Michel Lespinassebf181b92012-10-08 16:31:39 -0700486/*
487 * vma has some anon_vma assigned, and is already inserted on that
488 * anon_vma's interval trees.
489 *
490 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
491 * vma must be removed from the anon_vma's interval trees using
492 * anon_vma_interval_tree_pre_update_vma().
493 *
494 * After the update, the vma will be reinserted using
495 * anon_vma_interval_tree_post_update_vma().
496 *
497 * The entire update must be protected by exclusive mmap_sem and by
498 * the root anon_vma's mutex.
499 */
500static inline void
501anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
502{
503 struct anon_vma_chain *avc;
504
505 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
506 anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
507}
508
509static inline void
510anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
511{
512 struct anon_vma_chain *avc;
513
514 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
515 anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
516}
517
Hugh Dickins6597d782012-10-08 16:29:07 -0700518static int find_vma_links(struct mm_struct *mm, unsigned long addr,
519 unsigned long end, struct vm_area_struct **pprev,
520 struct rb_node ***rb_link, struct rb_node **rb_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521{
Hugh Dickins6597d782012-10-08 16:29:07 -0700522 struct rb_node **__rb_link, *__rb_parent, *rb_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523
524 __rb_link = &mm->mm_rb.rb_node;
525 rb_prev = __rb_parent = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
527 while (*__rb_link) {
528 struct vm_area_struct *vma_tmp;
529
530 __rb_parent = *__rb_link;
531 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
532
533 if (vma_tmp->vm_end > addr) {
Hugh Dickins6597d782012-10-08 16:29:07 -0700534 /* Fail if an existing vma overlaps the area */
535 if (vma_tmp->vm_start < end)
536 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 __rb_link = &__rb_parent->rb_left;
538 } else {
539 rb_prev = __rb_parent;
540 __rb_link = &__rb_parent->rb_right;
541 }
542 }
543
544 *pprev = NULL;
545 if (rb_prev)
546 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
547 *rb_link = __rb_link;
548 *rb_parent = __rb_parent;
Hugh Dickins6597d782012-10-08 16:29:07 -0700549 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550}
551
Cyril Hrubise8420a82013-04-29 15:08:33 -0700552static unsigned long count_vma_pages_range(struct mm_struct *mm,
553 unsigned long addr, unsigned long end)
554{
555 unsigned long nr_pages = 0;
556 struct vm_area_struct *vma;
557
558 /* Find first overlaping mapping */
559 vma = find_vma_intersection(mm, addr, end);
560 if (!vma)
561 return 0;
562
563 nr_pages = (min(end, vma->vm_end) -
564 max(addr, vma->vm_start)) >> PAGE_SHIFT;
565
566 /* Iterate over the rest of the overlaps */
567 for (vma = vma->vm_next; vma; vma = vma->vm_next) {
568 unsigned long overlap_len;
569
570 if (vma->vm_start > end)
571 break;
572
573 overlap_len = min(end, vma->vm_end) - vma->vm_start;
574 nr_pages += overlap_len >> PAGE_SHIFT;
575 }
576
577 return nr_pages;
578}
579
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
581 struct rb_node **rb_link, struct rb_node *rb_parent)
582{
Michel Lespinassed3737182012-12-11 16:01:38 -0800583 /* Update tracking information for the gap following the new vma. */
584 if (vma->vm_next)
585 vma_gap_update(vma->vm_next);
586 else
587 mm->highest_vm_end = vma->vm_end;
588
589 /*
590 * vma->vm_prev wasn't known when we followed the rbtree to find the
591 * correct insertion point for that vma. As a result, we could not
592 * update the vma vm_rb parents rb_subtree_gap values on the way down.
593 * So, we first insert the vma with a zero rb_subtree_gap value
594 * (to be consistent with what we did on the way down), and then
595 * immediately update the gap to the correct value. Finally we
596 * rebalance the rbtree after all augmented values have been set.
597 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
Michel Lespinassed3737182012-12-11 16:01:38 -0800599 vma->rb_subtree_gap = 0;
600 vma_gap_update(vma);
601 vma_rb_insert(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602}
603
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700604static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605{
ZhenwenXu48aae422009-01-06 14:40:21 -0800606 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
608 file = vma->vm_file;
609 if (file) {
610 struct address_space *mapping = file->f_mapping;
611
612 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500613 atomic_dec(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 if (vma->vm_flags & VM_SHARED)
615 mapping->i_mmap_writable++;
616
617 flush_dcache_mmap_lock(mapping);
618 if (unlikely(vma->vm_flags & VM_NONLINEAR))
619 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
620 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700621 vma_interval_tree_insert(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 flush_dcache_mmap_unlock(mapping);
623 }
624}
625
626static void
627__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
628 struct vm_area_struct *prev, struct rb_node **rb_link,
629 struct rb_node *rb_parent)
630{
631 __vma_link_list(mm, vma, prev, rb_parent);
632 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633}
634
635static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
636 struct vm_area_struct *prev, struct rb_node **rb_link,
637 struct rb_node *rb_parent)
638{
639 struct address_space *mapping = NULL;
640
641 if (vma->vm_file)
642 mapping = vma->vm_file->f_mapping;
643
Peter Zijlstra97a89412011-05-24 17:12:04 -0700644 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700645 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646
647 __vma_link(mm, vma, prev, rb_link, rb_parent);
648 __vma_link_file(vma);
649
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700651 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652
653 mm->map_count++;
654 validate_mm(mm);
655}
656
657/*
Kautuk Consul88f6b4c2012-03-21 16:34:16 -0700658 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700659 * mm's list and rbtree. It has already been inserted into the interval tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800661static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662{
Hugh Dickins6597d782012-10-08 16:29:07 -0700663 struct vm_area_struct *prev;
ZhenwenXu48aae422009-01-06 14:40:21 -0800664 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
Hugh Dickins6597d782012-10-08 16:29:07 -0700666 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
667 &prev, &rb_link, &rb_parent))
668 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 __vma_link(mm, vma, prev, rb_link, rb_parent);
670 mm->map_count++;
671}
672
673static inline void
674__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
675 struct vm_area_struct *prev)
676{
Michel Lespinassed3737182012-12-11 16:01:38 -0800677 struct vm_area_struct *next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700678
Michel Lespinassed3737182012-12-11 16:01:38 -0800679 vma_rb_erase(vma, &mm->mm_rb);
680 prev->vm_next = next = vma->vm_next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700681 if (next)
682 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 if (mm->mmap_cache == vma)
684 mm->mmap_cache = prev;
685}
686
687/*
688 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
689 * is already present in an i_mmap tree without adjusting the tree.
690 * The following helper function should be used when such adjustments
691 * are necessary. The "insert" vma (if any) is to be inserted
692 * before we drop the necessary locks.
693 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800694int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
696{
697 struct mm_struct *mm = vma->vm_mm;
698 struct vm_area_struct *next = vma->vm_next;
699 struct vm_area_struct *importer = NULL;
700 struct address_space *mapping = NULL;
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700701 struct rb_root *root = NULL;
Rik van Riel012f18002010-08-09 17:18:40 -0700702 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 struct file *file = vma->vm_file;
Michel Lespinassed3737182012-12-11 16:01:38 -0800704 bool start_changed = false, end_changed = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 long adjust_next = 0;
706 int remove_next = 0;
707
708 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700709 struct vm_area_struct *exporter = NULL;
710
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 if (end >= next->vm_end) {
712 /*
713 * vma expands, overlapping all the next, and
714 * perhaps the one after too (mprotect case 6).
715 */
716again: remove_next = 1 + (end > next->vm_end);
717 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700718 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 importer = vma;
720 } else if (end > next->vm_start) {
721 /*
722 * vma expands, overlapping part of the next:
723 * mprotect case 5 shifting the boundary up.
724 */
725 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700726 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 importer = vma;
728 } else if (end < vma->vm_end) {
729 /*
730 * vma shrinks, and !insert tells it's not
731 * split_vma inserting another: so it must be
732 * mprotect case 4 shifting the boundary down.
733 */
734 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700735 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 importer = next;
737 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738
Rik van Riel5beb4932010-03-05 13:42:07 -0800739 /*
740 * Easily overlooked: when mprotect shifts the boundary,
741 * make sure the expanding vma has anon_vma set if the
742 * shrinking vma had, to cover any anon pages imported.
743 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700744 if (exporter && exporter->anon_vma && !importer->anon_vma) {
745 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800746 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700747 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800748 }
749 }
750
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 if (file) {
752 mapping = file->f_mapping;
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530753 if (!(vma->vm_flags & VM_NONLINEAR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 root = &mapping->i_mmap;
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530755 uprobe_munmap(vma, vma->vm_start, vma->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530756
757 if (adjust_next)
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530758 uprobe_munmap(next, next->vm_start,
759 next->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530760 }
761
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700762 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 if (insert) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 /*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700765 * Put into interval tree now, so instantiated pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 * are visible to arm/parisc __flush_dcache_page
767 * throughout; but we cannot insert into address
768 * space until vma start or end is updated.
769 */
770 __vma_link_file(insert);
771 }
772 }
773
Andrea Arcangeli94fcc582011-01-13 15:47:08 -0800774 vma_adjust_trans_huge(vma, start, end, adjust_next);
775
Michel Lespinassebf181b92012-10-08 16:31:39 -0700776 anon_vma = vma->anon_vma;
777 if (!anon_vma && adjust_next)
778 anon_vma = next->anon_vma;
779 if (anon_vma) {
Michel Lespinasseca42b262012-10-08 16:30:01 -0700780 VM_BUG_ON(adjust_next && next->anon_vma &&
781 anon_vma != next->anon_vma);
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000782 anon_vma_lock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700783 anon_vma_interval_tree_pre_update_vma(vma);
784 if (adjust_next)
785 anon_vma_interval_tree_pre_update_vma(next);
786 }
Rik van Riel012f18002010-08-09 17:18:40 -0700787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 if (root) {
789 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700790 vma_interval_tree_remove(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700792 vma_interval_tree_remove(next, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 }
794
Michel Lespinassed3737182012-12-11 16:01:38 -0800795 if (start != vma->vm_start) {
796 vma->vm_start = start;
797 start_changed = true;
798 }
799 if (end != vma->vm_end) {
800 vma->vm_end = end;
801 end_changed = true;
802 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 vma->vm_pgoff = pgoff;
804 if (adjust_next) {
805 next->vm_start += adjust_next << PAGE_SHIFT;
806 next->vm_pgoff += adjust_next;
807 }
808
809 if (root) {
810 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700811 vma_interval_tree_insert(next, root);
812 vma_interval_tree_insert(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 flush_dcache_mmap_unlock(mapping);
814 }
815
816 if (remove_next) {
817 /*
818 * vma_merge has merged next into vma, and needs
819 * us to remove next before dropping the locks.
820 */
821 __vma_unlink(mm, next, vma);
822 if (file)
823 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 } else if (insert) {
825 /*
826 * split_vma has split insert from vma, and needs
827 * us to insert it before dropping the locks
828 * (it may either follow vma or precede it).
829 */
830 __insert_vm_struct(mm, insert);
Michel Lespinassed3737182012-12-11 16:01:38 -0800831 } else {
832 if (start_changed)
833 vma_gap_update(vma);
834 if (end_changed) {
835 if (!next)
836 mm->highest_vm_end = end;
837 else if (!adjust_next)
838 vma_gap_update(next);
839 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 }
841
Michel Lespinassebf181b92012-10-08 16:31:39 -0700842 if (anon_vma) {
843 anon_vma_interval_tree_post_update_vma(vma);
844 if (adjust_next)
845 anon_vma_interval_tree_post_update_vma(next);
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -0800846 anon_vma_unlock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700847 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700849 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530851 if (root) {
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100852 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530853
854 if (adjust_next)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100855 uprobe_mmap(next);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530856 }
857
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700859 if (file) {
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530860 uprobe_munmap(next, next->vm_start, next->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700862 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800863 if (next->anon_vma)
864 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 mm->map_count--;
Oleg Nesterov3964acd2013-07-31 13:53:28 -0700866 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 kmem_cache_free(vm_area_cachep, next);
868 /*
869 * In mprotect's case 6 (see comments on vma_merge),
870 * we must remove another next too. It would clutter
871 * up the code too much to do both in one go.
872 */
Michel Lespinassed3737182012-12-11 16:01:38 -0800873 next = vma->vm_next;
874 if (remove_next == 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 goto again;
Michel Lespinassed3737182012-12-11 16:01:38 -0800876 else if (next)
877 vma_gap_update(next);
878 else
879 mm->highest_vm_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530881 if (insert && file)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100882 uprobe_mmap(insert);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883
884 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800885
886 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887}
888
889/*
890 * If the vma has a ->close operation then the driver probably needs to release
891 * per-vma resources, so we don't attempt to merge those.
892 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893static inline int is_mergeable_vma(struct vm_area_struct *vma,
894 struct file *file, unsigned long vm_flags)
895{
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -0700896 if (vma->vm_flags ^ vm_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 return 0;
898 if (vma->vm_file != file)
899 return 0;
900 if (vma->vm_ops && vma->vm_ops->close)
901 return 0;
902 return 1;
903}
904
905static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
Shaohua Li965f55d2011-05-24 17:11:20 -0700906 struct anon_vma *anon_vma2,
907 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908{
Shaohua Li965f55d2011-05-24 17:11:20 -0700909 /*
910 * The list_is_singular() test is to avoid merging VMA cloned from
911 * parents. This can improve scalability caused by anon_vma lock.
912 */
913 if ((!anon_vma1 || !anon_vma2) && (!vma ||
914 list_is_singular(&vma->anon_vma_chain)))
915 return 1;
916 return anon_vma1 == anon_vma2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917}
918
919/*
920 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
921 * in front of (at a lower virtual address and file offset than) the vma.
922 *
923 * We cannot merge two vmas if they have differently assigned (non-NULL)
924 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
925 *
926 * We don't check here for the merged mmap wrapping around the end of pagecache
927 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
928 * wrap, nor mmaps which cover the final page at index -1UL.
929 */
930static int
931can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
932 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
933{
934 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700935 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936 if (vma->vm_pgoff == vm_pgoff)
937 return 1;
938 }
939 return 0;
940}
941
942/*
943 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
944 * beyond (at a higher virtual address and file offset than) the vma.
945 *
946 * We cannot merge two vmas if they have differently assigned (non-NULL)
947 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
948 */
949static int
950can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
951 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
952{
953 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700954 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 pgoff_t vm_pglen;
Libind6e93212013-07-03 15:01:26 -0700956 vm_pglen = vma_pages(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
958 return 1;
959 }
960 return 0;
961}
962
963/*
964 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
965 * whether that can be merged with its predecessor or its successor.
966 * Or both (it neatly fills a hole).
967 *
968 * In most cases - when called for mmap, brk or mremap - [addr,end) is
969 * certain not to be mapped by the time vma_merge is called; but when
970 * called for mprotect, it is certain to be already mapped (either at
971 * an offset within prev, or at the start of next), and the flags of
972 * this area are about to be changed to vm_flags - and the no-change
973 * case has already been eliminated.
974 *
975 * The following mprotect cases have to be considered, where AAAA is
976 * the area passed down from mprotect_fixup, never extending beyond one
977 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
978 *
979 * AAAA AAAA AAAA AAAA
980 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
981 * cannot merge might become might become might become
982 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
983 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
984 * mremap move: PPPPNNNNNNNN 8
985 * AAAA
986 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
987 * might become case 1 below case 2 below case 3 below
988 *
989 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
990 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
991 */
992struct vm_area_struct *vma_merge(struct mm_struct *mm,
993 struct vm_area_struct *prev, unsigned long addr,
994 unsigned long end, unsigned long vm_flags,
995 struct anon_vma *anon_vma, struct file *file,
996 pgoff_t pgoff, struct mempolicy *policy)
997{
998 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
999 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -08001000 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001
1002 /*
1003 * We later require that vma->vm_flags == vm_flags,
1004 * so this tests vma->vm_flags & VM_SPECIAL, too.
1005 */
1006 if (vm_flags & VM_SPECIAL)
1007 return NULL;
1008
1009 if (prev)
1010 next = prev->vm_next;
1011 else
1012 next = mm->mmap;
1013 area = next;
1014 if (next && next->vm_end == end) /* cases 6, 7, 8 */
1015 next = next->vm_next;
1016
1017 /*
1018 * Can it merge with the predecessor?
1019 */
1020 if (prev && prev->vm_end == addr &&
1021 mpol_equal(vma_policy(prev), policy) &&
1022 can_vma_merge_after(prev, vm_flags,
1023 anon_vma, file, pgoff)) {
1024 /*
1025 * OK, it can. Can we now merge in the successor as well?
1026 */
1027 if (next && end == next->vm_start &&
1028 mpol_equal(policy, vma_policy(next)) &&
1029 can_vma_merge_before(next, vm_flags,
1030 anon_vma, file, pgoff+pglen) &&
1031 is_mergeable_anon_vma(prev->anon_vma,
Shaohua Li965f55d2011-05-24 17:11:20 -07001032 next->anon_vma, NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001034 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 next->vm_end, prev->vm_pgoff, NULL);
1036 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001037 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001039 if (err)
1040 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001041 khugepaged_enter_vma_merge(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 return prev;
1043 }
1044
1045 /*
1046 * Can this new request be merged in front of next?
1047 */
1048 if (next && end == next->vm_start &&
1049 mpol_equal(policy, vma_policy(next)) &&
1050 can_vma_merge_before(next, vm_flags,
1051 anon_vma, file, pgoff+pglen)) {
1052 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001053 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 addr, prev->vm_pgoff, NULL);
1055 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001056 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001058 if (err)
1059 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001060 khugepaged_enter_vma_merge(area);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 return area;
1062 }
1063
1064 return NULL;
1065}
1066
1067/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001068 * Rough compatbility check to quickly see if it's even worth looking
1069 * at sharing an anon_vma.
1070 *
1071 * They need to have the same vm_file, and the flags can only differ
1072 * in things that mprotect may change.
1073 *
1074 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1075 * we can merge the two vma's. For example, we refuse to merge a vma if
1076 * there is a vm_ops->close() function, because that indicates that the
1077 * driver is doing some kind of reference counting. But that doesn't
1078 * really matter for the anon_vma sharing case.
1079 */
1080static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1081{
1082 return a->vm_end == b->vm_start &&
1083 mpol_equal(vma_policy(a), vma_policy(b)) &&
1084 a->vm_file == b->vm_file &&
1085 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
1086 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1087}
1088
1089/*
1090 * Do some basic sanity checking to see if we can re-use the anon_vma
1091 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1092 * the same as 'old', the other will be the new one that is trying
1093 * to share the anon_vma.
1094 *
1095 * NOTE! This runs with mm_sem held for reading, so it is possible that
1096 * the anon_vma of 'old' is concurrently in the process of being set up
1097 * by another page fault trying to merge _that_. But that's ok: if it
1098 * is being set up, that automatically means that it will be a singleton
1099 * acceptable for merging, so we can do all of this optimistically. But
1100 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
1101 *
1102 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1103 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1104 * is to return an anon_vma that is "complex" due to having gone through
1105 * a fork).
1106 *
1107 * We also make sure that the two vma's are compatible (adjacent,
1108 * and with the same memory policies). That's all stable, even with just
1109 * a read lock on the mm_sem.
1110 */
1111static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1112{
1113 if (anon_vma_compatible(a, b)) {
1114 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
1115
1116 if (anon_vma && list_is_singular(&old->anon_vma_chain))
1117 return anon_vma;
1118 }
1119 return NULL;
1120}
1121
1122/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1124 * neighbouring vmas for a suitable anon_vma, before it goes off
1125 * to allocate a new anon_vma. It checks because a repetitive
1126 * sequence of mprotects and faults may otherwise lead to distinct
1127 * anon_vmas being allocated, preventing vma merge in subsequent
1128 * mprotect.
1129 */
1130struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1131{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001132 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134
1135 near = vma->vm_next;
1136 if (!near)
1137 goto try_prev;
1138
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001139 anon_vma = reusable_anon_vma(near, vma, near);
1140 if (anon_vma)
1141 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142try_prev:
Linus Torvalds9be34c92011-06-16 00:35:09 -07001143 near = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 if (!near)
1145 goto none;
1146
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001147 anon_vma = reusable_anon_vma(near, near, vma);
1148 if (anon_vma)
1149 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150none:
1151 /*
1152 * There's no absolute need to look only at touching neighbours:
1153 * we could search further afield for "compatible" anon_vmas.
1154 * But it would probably just be a waste of time searching,
1155 * or lead to too many vmas hanging off the same anon_vma.
1156 * We're trying to allow mprotect remerging later on,
1157 * not trying to minimize memory used for anon_vmas.
1158 */
1159 return NULL;
1160}
1161
1162#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001163void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 struct file *file, long pages)
1165{
1166 const unsigned long stack_flags
1167 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
1168
Huang Shijie44de9d02012-07-31 16:41:49 -07001169 mm->total_vm += pages;
1170
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 if (file) {
1172 mm->shared_vm += pages;
1173 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
1174 mm->exec_vm += pages;
1175 } else if (flags & stack_flags)
1176 mm->stack_vm += pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177}
1178#endif /* CONFIG_PROC_FS */
1179
1180/*
Al Viro40401532012-02-13 03:58:52 +00001181 * If a hint addr is less than mmap_min_addr change hint to be as
1182 * low as possible but still greater than mmap_min_addr
1183 */
1184static inline unsigned long round_hint_to_min(unsigned long hint)
1185{
1186 hint &= PAGE_MASK;
1187 if (((void *)hint != NULL) &&
1188 (hint < mmap_min_addr))
1189 return PAGE_ALIGN(mmap_min_addr);
1190 return hint;
1191}
1192
1193/*
Jianjun Kong27f5de72009-09-17 19:26:26 -07001194 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 */
1196
Al Viroe3fc6292012-05-30 20:08:42 -04001197unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 unsigned long len, unsigned long prot,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001199 unsigned long flags, unsigned long pgoff,
Michel Lespinasse41badc12013-02-22 16:32:47 -08001200 unsigned long *populate)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201{
1202 struct mm_struct * mm = current->mm;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001203 vm_flags_t vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
Michel Lespinasse41badc12013-02-22 16:32:47 -08001205 *populate = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001206
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 /*
1208 * Does the application expect PROT_READ to imply PROT_EXEC?
1209 *
1210 * (the exception is when the underlying filesystem is noexec
1211 * mounted, in which case we dont add PROT_EXEC.)
1212 */
1213 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001214 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 prot |= PROT_EXEC;
1216
1217 if (!len)
1218 return -EINVAL;
1219
Eric Paris7cd94142007-11-26 18:47:40 -05001220 if (!(flags & MAP_FIXED))
1221 addr = round_hint_to_min(addr);
1222
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223 /* Careful about overflows.. */
1224 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -05001225 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 return -ENOMEM;
1227
1228 /* offset overflow? */
1229 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1230 return -EOVERFLOW;
1231
1232 /* Too many mappings? */
1233 if (mm->map_count > sysctl_max_map_count)
1234 return -ENOMEM;
1235
1236 /* Obtain the address to map to. we verify (or select) it and ensure
1237 * that it represents a valid section of the address space.
1238 */
1239 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1240 if (addr & ~PAGE_MASK)
1241 return addr;
1242
1243 /* Do simple checking here so the lower-level routines won't have
1244 * to. we assume access permissions have been handled by the open
1245 * of the memory object, so we don't do any here.
1246 */
1247 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1248 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1249
Huang Shijiecdf7b342009-09-21 17:03:36 -07001250 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 if (!can_do_mlock())
1252 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 /* mlock MCL_FUTURE? */
1255 if (vm_flags & VM_LOCKED) {
1256 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001257 locked = len >> PAGE_SHIFT;
1258 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001259 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001260 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1262 return -EAGAIN;
1263 }
1264
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 if (file) {
Oleg Nesterov077bf222013-09-11 14:20:19 -07001266 struct inode *inode = file_inode(file);
1267
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268 switch (flags & MAP_TYPE) {
1269 case MAP_SHARED:
1270 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1271 return -EACCES;
1272
1273 /*
1274 * Make sure we don't allow writing to an append-only
1275 * file..
1276 */
1277 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1278 return -EACCES;
1279
1280 /*
1281 * Make sure there are no mandatory locks on the file.
1282 */
1283 if (locks_verify_locked(inode))
1284 return -EAGAIN;
1285
1286 vm_flags |= VM_SHARED | VM_MAYSHARE;
1287 if (!(file->f_mode & FMODE_WRITE))
1288 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1289
1290 /* fall through */
1291 case MAP_PRIVATE:
1292 if (!(file->f_mode & FMODE_READ))
1293 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001294 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001295 if (vm_flags & VM_EXEC)
1296 return -EPERM;
1297 vm_flags &= ~VM_MAYEXEC;
1298 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001299
Al Viro72c2d532013-09-22 16:27:52 -04001300 if (!file->f_op->mmap)
Linus Torvalds80c56062006-10-15 14:09:55 -07001301 return -ENODEV;
Oleg Nesterovb2c56e42013-09-11 14:20:18 -07001302 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1303 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 break;
1305
1306 default:
1307 return -EINVAL;
1308 }
1309 } else {
1310 switch (flags & MAP_TYPE) {
1311 case MAP_SHARED:
Oleg Nesterovb2c56e42013-09-11 14:20:18 -07001312 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1313 return -EINVAL;
Tejun Heoce363942008-09-03 16:09:47 +02001314 /*
1315 * Ignore pgoff.
1316 */
1317 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 vm_flags |= VM_SHARED | VM_MAYSHARE;
1319 break;
1320 case MAP_PRIVATE:
1321 /*
1322 * Set pgoff according to addr for anon_vma.
1323 */
1324 pgoff = addr >> PAGE_SHIFT;
1325 break;
1326 default:
1327 return -EINVAL;
1328 }
1329 }
1330
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001331 /*
1332 * Set 'VM_NORESERVE' if we should not account for the
1333 * memory use of this mapping.
1334 */
1335 if (flags & MAP_NORESERVE) {
1336 /* We honor MAP_NORESERVE if allowed to overcommit */
1337 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1338 vm_flags |= VM_NORESERVE;
1339
1340 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1341 if (file && is_file_hugepages(file))
1342 vm_flags |= VM_NORESERVE;
1343 }
1344
1345 addr = mmap_region(file, addr, len, vm_flags, pgoff);
Michel Lespinasse09a9f1d2013-03-28 16:26:23 -07001346 if (!IS_ERR_VALUE(addr) &&
1347 ((vm_flags & VM_LOCKED) ||
1348 (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
Michel Lespinasse41badc12013-02-22 16:32:47 -08001349 *populate = len;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001350 return addr;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001351}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001352
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001353SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1354 unsigned long, prot, unsigned long, flags,
1355 unsigned long, fd, unsigned long, pgoff)
1356{
1357 struct file *file = NULL;
1358 unsigned long retval = -EBADF;
1359
1360 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001361 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001362 file = fget(fd);
1363 if (!file)
1364 goto out;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001365 if (is_file_hugepages(file))
1366 len = ALIGN(len, huge_page_size(hstate_file(file)));
Jörn Engel493af572013-07-08 16:00:26 -07001367 retval = -EINVAL;
1368 if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
1369 goto out_fput;
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001370 } else if (flags & MAP_HUGETLB) {
1371 struct user_struct *user = NULL;
Andrew Mortonc103a4d2013-07-08 16:01:08 -07001372 struct hstate *hs;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001373
Andrew Mortonc103a4d2013-07-08 16:01:08 -07001374 hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK);
Li Zefan091d0d52013-05-09 15:08:15 +08001375 if (!hs)
1376 return -EINVAL;
1377
1378 len = ALIGN(len, huge_page_size(hs));
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001379 /*
1380 * VM_NORESERVE is used because the reservations will be
1381 * taken when vm_ops->mmap() is called
1382 * A dummy user value is used because we are not locking
1383 * memory so no accounting is necessary
1384 */
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -07001385 file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
Andi Kleen42d73952012-12-11 16:01:34 -08001386 VM_NORESERVE,
1387 &user, HUGETLB_ANONHUGE_INODE,
1388 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001389 if (IS_ERR(file))
1390 return PTR_ERR(file);
1391 }
1392
1393 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1394
Al Viroeb36c582012-05-30 20:17:35 -04001395 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Jörn Engel493af572013-07-08 16:00:26 -07001396out_fput:
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001397 if (file)
1398 fput(file);
1399out:
1400 return retval;
1401}
1402
Christoph Hellwiga4679372010-03-10 15:21:15 -08001403#ifdef __ARCH_WANT_SYS_OLD_MMAP
1404struct mmap_arg_struct {
1405 unsigned long addr;
1406 unsigned long len;
1407 unsigned long prot;
1408 unsigned long flags;
1409 unsigned long fd;
1410 unsigned long offset;
1411};
1412
1413SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1414{
1415 struct mmap_arg_struct a;
1416
1417 if (copy_from_user(&a, arg, sizeof(a)))
1418 return -EFAULT;
1419 if (a.offset & ~PAGE_MASK)
1420 return -EINVAL;
1421
1422 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1423 a.offset >> PAGE_SHIFT);
1424}
1425#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1426
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001427/*
1428 * Some shared mappigns will want the pages marked read-only
1429 * to track write events. If so, we'll downgrade vm_page_prot
1430 * to the private version (using protection_map[] without the
1431 * VM_SHARED bit).
1432 */
1433int vma_wants_writenotify(struct vm_area_struct *vma)
1434{
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001435 vm_flags_t vm_flags = vma->vm_flags;
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001436
1437 /* If it was private or non-writable, the write bit is already clear */
1438 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1439 return 0;
1440
1441 /* The backer wishes to know when pages are first written to? */
1442 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1443 return 1;
1444
1445 /* The open routine did something to the protections already? */
1446 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001447 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001448 return 0;
1449
1450 /* Specialty mapping? */
Konstantin Khlebnikov4b6e1e32012-10-08 16:28:40 -07001451 if (vm_flags & VM_PFNMAP)
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001452 return 0;
1453
1454 /* Can the mapping track the dirty pages? */
1455 return vma->vm_file && vma->vm_file->f_mapping &&
1456 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1457}
1458
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001459/*
1460 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001461 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001462 */
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001463static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001464{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001465 /*
1466 * hugetlb has its own accounting separate from the core VM
1467 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1468 */
1469 if (file && is_file_hugepages(file))
1470 return 0;
1471
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001472 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1473}
1474
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001475unsigned long mmap_region(struct file *file, unsigned long addr,
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001476 unsigned long len, vm_flags_t vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001477{
1478 struct mm_struct *mm = current->mm;
1479 struct vm_area_struct *vma, *prev;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001480 int error;
1481 struct rb_node **rb_link, *rb_parent;
1482 unsigned long charged = 0;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001483
Cyril Hrubise8420a82013-04-29 15:08:33 -07001484 /* Check against address space limit. */
1485 if (!may_expand_vm(mm, len >> PAGE_SHIFT)) {
1486 unsigned long nr_pages;
1487
1488 /*
1489 * MAP_FIXED may remove pages of mappings that intersects with
1490 * requested mapping. Account for the pages it would unmap.
1491 */
1492 if (!(vm_flags & MAP_FIXED))
1493 return -ENOMEM;
1494
1495 nr_pages = count_vma_pages_range(mm, addr, addr + len);
1496
1497 if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages))
1498 return -ENOMEM;
1499 }
1500
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501 /* Clear old maps */
1502 error = -ENOMEM;
1503munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07001504 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 if (do_munmap(mm, addr, len))
1506 return -ENOMEM;
1507 goto munmap_back;
1508 }
1509
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001510 /*
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001511 * Private writable mapping: check memory availability
1512 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001513 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001514 charged = len >> PAGE_SHIFT;
Al Viro191c5422012-02-13 03:58:52 +00001515 if (security_vm_enough_memory_mm(mm, charged))
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001516 return -ENOMEM;
1517 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 }
1519
1520 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001521 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001523 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1524 if (vma)
1525 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526
1527 /*
1528 * Determine the object being mapped and call the appropriate
1529 * specific mapper. the address has already been validated, but
1530 * not unmapped, but the maps are removed from the list.
1531 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001532 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 if (!vma) {
1534 error = -ENOMEM;
1535 goto unacct_error;
1536 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537
1538 vma->vm_mm = mm;
1539 vma->vm_start = addr;
1540 vma->vm_end = addr + len;
1541 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001542 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001544 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545
1546 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547 if (vm_flags & VM_DENYWRITE) {
1548 error = deny_write_access(file);
1549 if (error)
1550 goto free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 }
Al Virocb0942b2012-08-27 14:48:26 -04001552 vma->vm_file = get_file(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 error = file->f_op->mmap(file, vma);
1554 if (error)
1555 goto unmap_and_free_vma;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001556
1557 /* Can addr have changed??
1558 *
1559 * Answer: Yes, several device drivers can do it in their
1560 * f_op->mmap method. -DaveM
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001561 * Bug: If addr is changed, prev, rb_link, rb_parent should
1562 * be updated for vma_link()
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001563 */
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001564 WARN_ON_ONCE(addr != vma->vm_start);
1565
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001566 addr = vma->vm_start;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001567 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568 } else if (vm_flags & VM_SHARED) {
1569 error = shmem_zero_setup(vma);
1570 if (error)
1571 goto free_vma;
1572 }
1573
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001574 if (vma_wants_writenotify(vma)) {
1575 pgprot_t pprot = vma->vm_page_prot;
1576
1577 /* Can vma->vm_page_prot have changed??
1578 *
1579 * Answer: Yes, drivers may have changed it in their
1580 * f_op->mmap method.
1581 *
1582 * Ensures that vmas marked as uncached stay that way.
1583 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001584 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001585 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1586 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1587 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001588
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001589 vma_link(mm, vma, prev, rb_link, rb_parent);
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001590 /* Once vma denies write, undo our temporary denial count */
Oleg Nesterove8686772013-09-11 14:20:20 -07001591 if (vm_flags & VM_DENYWRITE)
1592 allow_write_access(file);
1593 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001594out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001595 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001596
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001597 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001598 if (vm_flags & VM_LOCKED) {
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001599 if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) ||
1600 vma == get_gate_vma(current->mm)))
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001601 mm->locked_vm += (len >> PAGE_SHIFT);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001602 else
1603 vma->vm_flags &= ~VM_LOCKED;
1604 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301605
Oleg Nesterovc7a3a882012-08-19 19:10:42 +02001606 if (file)
1607 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301608
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07001609 /*
1610 * New (or expanded) vma always get soft dirty status.
1611 * Otherwise user-space soft-dirty page tracker won't
1612 * be able to distinguish situation when vma area unmapped,
1613 * then new mapped in-place (which must be aimed as
1614 * a completely new data area).
1615 */
1616 vma->vm_flags |= VM_SOFTDIRTY;
1617
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618 return addr;
1619
1620unmap_and_free_vma:
Oleg Nesterove8686772013-09-11 14:20:20 -07001621 if (vm_flags & VM_DENYWRITE)
1622 allow_write_access(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623 vma->vm_file = NULL;
1624 fput(file);
1625
1626 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001627 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1628 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629free_vma:
1630 kmem_cache_free(vm_area_cachep, vma);
1631unacct_error:
1632 if (charged)
1633 vm_unacct_memory(charged);
1634 return error;
1635}
1636
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001637unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1638{
1639 /*
1640 * We implement the search by looking for an rbtree node that
1641 * immediately follows a suitable gap. That is,
1642 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1643 * - gap_end = vma->vm_start >= info->low_limit + length;
1644 * - gap_end - gap_start >= length
1645 */
1646
1647 struct mm_struct *mm = current->mm;
1648 struct vm_area_struct *vma;
1649 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1650
1651 /* Adjust search length to account for worst case alignment overhead */
1652 length = info->length + info->align_mask;
1653 if (length < info->length)
1654 return -ENOMEM;
1655
1656 /* Adjust search limits by the desired length */
1657 if (info->high_limit < length)
1658 return -ENOMEM;
1659 high_limit = info->high_limit - length;
1660
1661 if (info->low_limit > high_limit)
1662 return -ENOMEM;
1663 low_limit = info->low_limit + length;
1664
1665 /* Check if rbtree root looks promising */
1666 if (RB_EMPTY_ROOT(&mm->mm_rb))
1667 goto check_highest;
1668 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1669 if (vma->rb_subtree_gap < length)
1670 goto check_highest;
1671
1672 while (true) {
1673 /* Visit left subtree if it looks promising */
1674 gap_end = vma->vm_start;
1675 if (gap_end >= low_limit && vma->vm_rb.rb_left) {
1676 struct vm_area_struct *left =
1677 rb_entry(vma->vm_rb.rb_left,
1678 struct vm_area_struct, vm_rb);
1679 if (left->rb_subtree_gap >= length) {
1680 vma = left;
1681 continue;
1682 }
1683 }
1684
1685 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1686check_current:
1687 /* Check if current node has a suitable gap */
1688 if (gap_start > high_limit)
1689 return -ENOMEM;
1690 if (gap_end >= low_limit && gap_end - gap_start >= length)
1691 goto found;
1692
1693 /* Visit right subtree if it looks promising */
1694 if (vma->vm_rb.rb_right) {
1695 struct vm_area_struct *right =
1696 rb_entry(vma->vm_rb.rb_right,
1697 struct vm_area_struct, vm_rb);
1698 if (right->rb_subtree_gap >= length) {
1699 vma = right;
1700 continue;
1701 }
1702 }
1703
1704 /* Go back up the rbtree to find next candidate node */
1705 while (true) {
1706 struct rb_node *prev = &vma->vm_rb;
1707 if (!rb_parent(prev))
1708 goto check_highest;
1709 vma = rb_entry(rb_parent(prev),
1710 struct vm_area_struct, vm_rb);
1711 if (prev == vma->vm_rb.rb_left) {
1712 gap_start = vma->vm_prev->vm_end;
1713 gap_end = vma->vm_start;
1714 goto check_current;
1715 }
1716 }
1717 }
1718
1719check_highest:
1720 /* Check highest gap, which does not precede any rbtree node */
1721 gap_start = mm->highest_vm_end;
1722 gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
1723 if (gap_start > high_limit)
1724 return -ENOMEM;
1725
1726found:
1727 /* We found a suitable gap. Clip it with the original low_limit. */
1728 if (gap_start < info->low_limit)
1729 gap_start = info->low_limit;
1730
1731 /* Adjust gap address to the desired alignment */
1732 gap_start += (info->align_offset - gap_start) & info->align_mask;
1733
1734 VM_BUG_ON(gap_start + info->length > info->high_limit);
1735 VM_BUG_ON(gap_start + info->length > gap_end);
1736 return gap_start;
1737}
1738
1739unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1740{
1741 struct mm_struct *mm = current->mm;
1742 struct vm_area_struct *vma;
1743 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1744
1745 /* Adjust search length to account for worst case alignment overhead */
1746 length = info->length + info->align_mask;
1747 if (length < info->length)
1748 return -ENOMEM;
1749
1750 /*
1751 * Adjust search limits by the desired length.
1752 * See implementation comment at top of unmapped_area().
1753 */
1754 gap_end = info->high_limit;
1755 if (gap_end < length)
1756 return -ENOMEM;
1757 high_limit = gap_end - length;
1758
1759 if (info->low_limit > high_limit)
1760 return -ENOMEM;
1761 low_limit = info->low_limit + length;
1762
1763 /* Check highest gap, which does not precede any rbtree node */
1764 gap_start = mm->highest_vm_end;
1765 if (gap_start <= high_limit)
1766 goto found_highest;
1767
1768 /* Check if rbtree root looks promising */
1769 if (RB_EMPTY_ROOT(&mm->mm_rb))
1770 return -ENOMEM;
1771 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1772 if (vma->rb_subtree_gap < length)
1773 return -ENOMEM;
1774
1775 while (true) {
1776 /* Visit right subtree if it looks promising */
1777 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1778 if (gap_start <= high_limit && vma->vm_rb.rb_right) {
1779 struct vm_area_struct *right =
1780 rb_entry(vma->vm_rb.rb_right,
1781 struct vm_area_struct, vm_rb);
1782 if (right->rb_subtree_gap >= length) {
1783 vma = right;
1784 continue;
1785 }
1786 }
1787
1788check_current:
1789 /* Check if current node has a suitable gap */
1790 gap_end = vma->vm_start;
1791 if (gap_end < low_limit)
1792 return -ENOMEM;
1793 if (gap_start <= high_limit && gap_end - gap_start >= length)
1794 goto found;
1795
1796 /* Visit left subtree if it looks promising */
1797 if (vma->vm_rb.rb_left) {
1798 struct vm_area_struct *left =
1799 rb_entry(vma->vm_rb.rb_left,
1800 struct vm_area_struct, vm_rb);
1801 if (left->rb_subtree_gap >= length) {
1802 vma = left;
1803 continue;
1804 }
1805 }
1806
1807 /* Go back up the rbtree to find next candidate node */
1808 while (true) {
1809 struct rb_node *prev = &vma->vm_rb;
1810 if (!rb_parent(prev))
1811 return -ENOMEM;
1812 vma = rb_entry(rb_parent(prev),
1813 struct vm_area_struct, vm_rb);
1814 if (prev == vma->vm_rb.rb_right) {
1815 gap_start = vma->vm_prev ?
1816 vma->vm_prev->vm_end : 0;
1817 goto check_current;
1818 }
1819 }
1820 }
1821
1822found:
1823 /* We found a suitable gap. Clip it with the original high_limit. */
1824 if (gap_end > info->high_limit)
1825 gap_end = info->high_limit;
1826
1827found_highest:
1828 /* Compute highest gap address at the desired alignment */
1829 gap_end -= info->length;
1830 gap_end -= (gap_end - info->align_offset) & info->align_mask;
1831
1832 VM_BUG_ON(gap_end < info->low_limit);
1833 VM_BUG_ON(gap_end < gap_start);
1834 return gap_end;
1835}
1836
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837/* Get an address range which is currently unmapped.
1838 * For shmat() with addr=0.
1839 *
1840 * Ugly calling convention alert:
1841 * Return value with the low bits set means error value,
1842 * ie
1843 * if (ret & ~PAGE_MASK)
1844 * error = ret;
1845 *
1846 * This function "knows" that -ENOMEM has the bits set.
1847 */
1848#ifndef HAVE_ARCH_UNMAPPED_AREA
1849unsigned long
1850arch_get_unmapped_area(struct file *filp, unsigned long addr,
1851 unsigned long len, unsigned long pgoff, unsigned long flags)
1852{
1853 struct mm_struct *mm = current->mm;
1854 struct vm_area_struct *vma;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001855 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001857 if (len > TASK_SIZE - mmap_min_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 return -ENOMEM;
1859
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001860 if (flags & MAP_FIXED)
1861 return addr;
1862
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 if (addr) {
1864 addr = PAGE_ALIGN(addr);
1865 vma = find_vma(mm, addr);
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001866 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 (!vma || addr + len <= vma->vm_start))
1868 return addr;
1869 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001871 info.flags = 0;
1872 info.length = len;
Heiko Carstens4e99b022013-11-12 15:07:54 -08001873 info.low_limit = mm->mmap_base;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001874 info.high_limit = TASK_SIZE;
1875 info.align_mask = 0;
1876 return vm_unmapped_area(&info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877}
1878#endif
1879
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880/*
1881 * This mmap-allocator allocates new areas top-down from below the
1882 * stack's low limit (the base):
1883 */
1884#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1885unsigned long
1886arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1887 const unsigned long len, const unsigned long pgoff,
1888 const unsigned long flags)
1889{
1890 struct vm_area_struct *vma;
1891 struct mm_struct *mm = current->mm;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001892 unsigned long addr = addr0;
1893 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894
1895 /* requested length too big for entire address space */
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001896 if (len > TASK_SIZE - mmap_min_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 return -ENOMEM;
1898
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001899 if (flags & MAP_FIXED)
1900 return addr;
1901
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 /* requesting a specific address */
1903 if (addr) {
1904 addr = PAGE_ALIGN(addr);
1905 vma = find_vma(mm, addr);
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001906 if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907 (!vma || addr + len <= vma->vm_start))
1908 return addr;
1909 }
1910
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001911 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
1912 info.length = len;
Akira Takeuchi2afc7452013-11-12 15:08:21 -08001913 info.low_limit = max(PAGE_SIZE, mmap_min_addr);
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001914 info.high_limit = mm->mmap_base;
1915 info.align_mask = 0;
1916 addr = vm_unmapped_area(&info);
Xiao Guangrongb716ad92012-03-21 16:33:56 -07001917
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918 /*
1919 * A failed mmap() very likely causes application failure,
1920 * so fall back to the bottom-up function here. This scenario
1921 * can happen with large stack limits and large mmap()
1922 * allocations.
1923 */
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001924 if (addr & ~PAGE_MASK) {
1925 VM_BUG_ON(addr != -ENOMEM);
1926 info.flags = 0;
1927 info.low_limit = TASK_UNMAPPED_BASE;
1928 info.high_limit = TASK_SIZE;
1929 addr = vm_unmapped_area(&info);
1930 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931
1932 return addr;
1933}
1934#endif
1935
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936unsigned long
1937get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1938 unsigned long pgoff, unsigned long flags)
1939{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001940 unsigned long (*get_area)(struct file *, unsigned long,
1941 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942
Al Viro9206de92009-12-03 15:23:11 -05001943 unsigned long error = arch_mmap_check(addr, len, flags);
1944 if (error)
1945 return error;
1946
1947 /* Careful about overflows.. */
1948 if (len > TASK_SIZE)
1949 return -ENOMEM;
1950
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001951 get_area = current->mm->get_unmapped_area;
Al Viro72c2d532013-09-22 16:27:52 -04001952 if (file && file->f_op->get_unmapped_area)
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001953 get_area = file->f_op->get_unmapped_area;
1954 addr = get_area(file, addr, len, pgoff, flags);
1955 if (IS_ERR_VALUE(addr))
1956 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001958 if (addr > TASK_SIZE - len)
1959 return -ENOMEM;
1960 if (addr & ~PAGE_MASK)
1961 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001962
Al Viro9ac4ed42012-05-30 17:13:15 -04001963 addr = arch_rebalance_pgtables(addr, len);
1964 error = security_mmap_addr(addr);
1965 return error ? error : addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966}
1967
1968EXPORT_SYMBOL(get_unmapped_area);
1969
1970/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001971struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972{
1973 struct vm_area_struct *vma = NULL;
1974
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001975 /* Check the cache first. */
1976 /* (Cache hit rate is typically around 35%.) */
Jan Stancekb6a9b7f2013-04-04 11:35:10 -07001977 vma = ACCESS_ONCE(mm->mmap_cache);
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001978 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1979 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001981 rb_node = mm->mm_rb.rb_node;
1982 vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001984 while (rb_node) {
1985 struct vm_area_struct *vma_tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001987 vma_tmp = rb_entry(rb_node,
1988 struct vm_area_struct, vm_rb);
1989
1990 if (vma_tmp->vm_end > addr) {
1991 vma = vma_tmp;
1992 if (vma_tmp->vm_start <= addr)
1993 break;
1994 rb_node = rb_node->rb_left;
1995 } else
1996 rb_node = rb_node->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001997 }
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001998 if (vma)
1999 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000 }
2001 return vma;
2002}
2003
2004EXPORT_SYMBOL(find_vma);
2005
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08002006/*
2007 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08002008 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009struct vm_area_struct *
2010find_vma_prev(struct mm_struct *mm, unsigned long addr,
2011 struct vm_area_struct **pprev)
2012{
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08002013 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08002015 vma = find_vma(mm, addr);
Mikulas Patocka83cd9042012-03-04 19:52:03 -05002016 if (vma) {
2017 *pprev = vma->vm_prev;
2018 } else {
2019 struct rb_node *rb_node = mm->mm_rb.rb_node;
2020 *pprev = NULL;
2021 while (rb_node) {
2022 *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
2023 rb_node = rb_node->rb_right;
2024 }
2025 }
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08002026 return vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027}
2028
2029/*
2030 * Verify that the stack growth is acceptable and
2031 * update accounting. This is shared with both the
2032 * grow-up and grow-down cases.
2033 */
ZhenwenXu48aae422009-01-06 14:40:21 -08002034static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035{
2036 struct mm_struct *mm = vma->vm_mm;
2037 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08002038 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039
2040 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002041 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042 return -ENOMEM;
2043
2044 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08002045 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 return -ENOMEM;
2047
2048 /* mlock limit tests */
2049 if (vma->vm_flags & VM_LOCKED) {
2050 unsigned long locked;
2051 unsigned long limit;
2052 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002053 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
2054 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 if (locked > limit && !capable(CAP_IPC_LOCK))
2056 return -ENOMEM;
2057 }
2058
Adam Litke0d59a012007-01-30 14:35:39 -08002059 /* Check to ensure the stack will not grow into a hugetlb-only region */
2060 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
2061 vma->vm_end - size;
2062 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
2063 return -EFAULT;
2064
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 /*
2066 * Overcommit.. This must be the final test, as it will
2067 * update security statistics.
2068 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01002069 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 return -ENOMEM;
2071
2072 /* Ok, everything looks good - let it rip */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073 if (vma->vm_flags & VM_LOCKED)
2074 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07002075 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002076 return 0;
2077}
2078
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002079#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002081 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2082 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002084int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085{
2086 int error;
2087
2088 if (!(vma->vm_flags & VM_GROWSUP))
2089 return -EFAULT;
2090
2091 /*
2092 * We must make sure the anon_vma is allocated
2093 * so that the anon_vma locking is not a noop.
2094 */
2095 if (unlikely(anon_vma_prepare(vma)))
2096 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07002097 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002098
2099 /*
2100 * vma->vm_start/vm_end cannot change under us because the caller
2101 * is required to hold the mmap_sem in read mode. We need the
2102 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01002103 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104 */
Helge Deller06b32f32006-12-19 19:28:33 +01002105 if (address < PAGE_ALIGN(address+4))
2106 address = PAGE_ALIGN(address+4);
2107 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07002108 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01002109 return -ENOMEM;
2110 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 error = 0;
2112
2113 /* Somebody else might have raced and expanded it already */
2114 if (address > vma->vm_end) {
2115 unsigned long size, grow;
2116
2117 size = address - vma->vm_start;
2118 grow = (address - vma->vm_end) >> PAGE_SHIFT;
2119
Hugh Dickins42c36f62011-05-09 17:44:42 -07002120 error = -ENOMEM;
2121 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
2122 error = acct_stack_growth(vma, size, grow);
2123 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002124 /*
2125 * vma_gap_update() doesn't support concurrent
2126 * updates, but we only hold a shared mmap_sem
2127 * lock here, so we need to protect against
2128 * concurrent vma expansions.
2129 * vma_lock_anon_vma() doesn't help here, as
2130 * we don't guarantee that all growable vmas
2131 * in a mm share the same root anon vma.
2132 * So, we reuse mm->page_table_lock to guard
2133 * against concurrent vma expansions.
2134 */
2135 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002136 anon_vma_interval_tree_pre_update_vma(vma);
Hugh Dickins42c36f62011-05-09 17:44:42 -07002137 vma->vm_end = address;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002138 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002139 if (vma->vm_next)
2140 vma_gap_update(vma->vm_next);
2141 else
2142 vma->vm_mm->highest_vm_end = address;
Michel Lespinasse41289972012-12-12 13:52:25 -08002143 spin_unlock(&vma->vm_mm->page_table_lock);
2144
Hugh Dickins42c36f62011-05-09 17:44:42 -07002145 perf_event_mmap(vma);
2146 }
Eric B Munson3af9e852010-05-18 15:30:49 +01002147 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002149 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002150 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002151 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002152 return error;
2153}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002154#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2155
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156/*
2157 * vma is the first one with address < vma->vm_start. Have to extend vma.
2158 */
Michal Hockod05f3162011-05-24 17:11:44 -07002159int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002160 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161{
2162 int error;
2163
2164 /*
2165 * We must make sure the anon_vma is allocated
2166 * so that the anon_vma locking is not a noop.
2167 */
2168 if (unlikely(anon_vma_prepare(vma)))
2169 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05002170
2171 address &= PAGE_MASK;
Al Viroe5467852012-05-30 13:30:51 -04002172 error = security_mmap_addr(address);
Eric Paris88694772007-11-26 18:47:26 -05002173 if (error)
2174 return error;
2175
Rik van Rielbb4a3402010-08-09 17:18:37 -07002176 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177
2178 /*
2179 * vma->vm_start/vm_end cannot change under us because the caller
2180 * is required to hold the mmap_sem in read mode. We need the
2181 * anon_vma lock to serialize against concurrent expand_stacks.
2182 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002183
2184 /* Somebody else might have raced and expanded it already */
2185 if (address < vma->vm_start) {
2186 unsigned long size, grow;
2187
2188 size = vma->vm_end - address;
2189 grow = (vma->vm_start - address) >> PAGE_SHIFT;
2190
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002191 error = -ENOMEM;
2192 if (grow <= vma->vm_pgoff) {
2193 error = acct_stack_growth(vma, size, grow);
2194 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002195 /*
2196 * vma_gap_update() doesn't support concurrent
2197 * updates, but we only hold a shared mmap_sem
2198 * lock here, so we need to protect against
2199 * concurrent vma expansions.
2200 * vma_lock_anon_vma() doesn't help here, as
2201 * we don't guarantee that all growable vmas
2202 * in a mm share the same root anon vma.
2203 * So, we reuse mm->page_table_lock to guard
2204 * against concurrent vma expansions.
2205 */
2206 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002207 anon_vma_interval_tree_pre_update_vma(vma);
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002208 vma->vm_start = address;
2209 vma->vm_pgoff -= grow;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002210 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002211 vma_gap_update(vma);
Michel Lespinasse41289972012-12-12 13:52:25 -08002212 spin_unlock(&vma->vm_mm->page_table_lock);
2213
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002214 perf_event_mmap(vma);
2215 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 }
2217 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002218 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002219 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002220 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221 return error;
2222}
2223
Linus Torvalds09884962013-02-27 08:36:04 -08002224/*
2225 * Note how expand_stack() refuses to expand the stack all the way to
2226 * abut the next virtual mapping, *unless* that mapping itself is also
2227 * a stack mapping. We want to leave room for a guard page, after all
2228 * (the guard page itself is not added here, that is done by the
2229 * actual page faulting logic)
2230 *
2231 * This matches the behavior of the guard page logic (see mm/memory.c:
2232 * check_stack_guard_page()), which only allows the guard page to be
2233 * removed under these circumstances.
2234 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002235#ifdef CONFIG_STACK_GROWSUP
2236int expand_stack(struct vm_area_struct *vma, unsigned long address)
2237{
Linus Torvalds09884962013-02-27 08:36:04 -08002238 struct vm_area_struct *next;
2239
2240 address &= PAGE_MASK;
2241 next = vma->vm_next;
2242 if (next && next->vm_start == address + PAGE_SIZE) {
2243 if (!(next->vm_flags & VM_GROWSUP))
2244 return -ENOMEM;
2245 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002246 return expand_upwards(vma, address);
2247}
2248
2249struct vm_area_struct *
2250find_extend_vma(struct mm_struct *mm, unsigned long addr)
2251{
2252 struct vm_area_struct *vma, *prev;
2253
2254 addr &= PAGE_MASK;
2255 vma = find_vma_prev(mm, addr, &prev);
2256 if (vma && (vma->vm_start <= addr))
2257 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01002258 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002259 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002260 if (prev->vm_flags & VM_LOCKED)
2261 __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL);
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002262 return prev;
2263}
2264#else
2265int expand_stack(struct vm_area_struct *vma, unsigned long address)
2266{
Linus Torvalds09884962013-02-27 08:36:04 -08002267 struct vm_area_struct *prev;
2268
2269 address &= PAGE_MASK;
2270 prev = vma->vm_prev;
2271 if (prev && prev->vm_end == address) {
2272 if (!(prev->vm_flags & VM_GROWSDOWN))
2273 return -ENOMEM;
2274 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002275 return expand_downwards(vma, address);
2276}
2277
Linus Torvalds1da177e2005-04-16 15:20:36 -07002278struct vm_area_struct *
2279find_extend_vma(struct mm_struct * mm, unsigned long addr)
2280{
2281 struct vm_area_struct * vma;
2282 unsigned long start;
2283
2284 addr &= PAGE_MASK;
2285 vma = find_vma(mm,addr);
2286 if (!vma)
2287 return NULL;
2288 if (vma->vm_start <= addr)
2289 return vma;
2290 if (!(vma->vm_flags & VM_GROWSDOWN))
2291 return NULL;
2292 start = vma->vm_start;
2293 if (expand_stack(vma, addr))
2294 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002295 if (vma->vm_flags & VM_LOCKED)
2296 __mlock_vma_pages_range(vma, addr, start, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297 return vma;
2298}
2299#endif
2300
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002302 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002304 *
2305 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002306 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002307static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002308{
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002309 unsigned long nr_accounted = 0;
2310
Hugh Dickins365e9c872005-10-29 18:16:18 -07002311 /* Update high watermark before we lower total_vm */
2312 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002313 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002314 long nrpages = vma_pages(vma);
2315
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002316 if (vma->vm_flags & VM_ACCOUNT)
2317 nr_accounted += nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002318 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002319 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07002320 } while (vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002321 vm_unacct_memory(nr_accounted);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322 validate_mm(mm);
2323}
2324
2325/*
2326 * Get rid of page table information in the indicated region.
2327 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07002328 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002329 */
2330static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07002331 struct vm_area_struct *vma, struct vm_area_struct *prev,
2332 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333{
Hugh Dickinse0da3822005-04-19 13:29:15 -07002334 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002335 struct mmu_gather tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336
2337 lru_add_drain();
Linus Torvalds2b047252013-08-15 11:42:25 -07002338 tlb_gather_mmu(&tlb, mm, start, end);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002339 update_hiwater_rss(mm);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002340 unmap_vmas(&tlb, vma, start, end);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002341 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
Hugh Dickins6ee86302013-04-29 15:07:44 -07002342 next ? next->vm_start : USER_PGTABLES_CEILING);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002343 tlb_finish_mmu(&tlb, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002344}
2345
2346/*
2347 * Create a list of vma's touched by the unmap, removing them from the mm's
2348 * vma list as we go..
2349 */
2350static void
2351detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
2352 struct vm_area_struct *prev, unsigned long end)
2353{
2354 struct vm_area_struct **insertion_point;
2355 struct vm_area_struct *tail_vma = NULL;
2356
2357 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002358 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 do {
Michel Lespinassed3737182012-12-11 16:01:38 -08002360 vma_rb_erase(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 mm->map_count--;
2362 tail_vma = vma;
2363 vma = vma->vm_next;
2364 } while (vma && vma->vm_start < end);
2365 *insertion_point = vma;
Michel Lespinassed3737182012-12-11 16:01:38 -08002366 if (vma) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002367 vma->vm_prev = prev;
Michel Lespinassed3737182012-12-11 16:01:38 -08002368 vma_gap_update(vma);
2369 } else
2370 mm->highest_vm_end = prev ? prev->vm_end : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002371 tail_vma->vm_next = NULL;
2372 mm->mmap_cache = NULL; /* Kill the cache. */
2373}
2374
2375/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002376 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
2377 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002379static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 unsigned long addr, int new_below)
2381{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08002383 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002384
Andi Kleena5516432008-07-23 21:27:41 -07002385 if (is_vm_hugetlb_page(vma) && (addr &
2386 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002387 return -EINVAL;
2388
Christoph Lametere94b1762006-12-06 20:33:17 -08002389 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002390 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08002391 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392
2393 /* most fields are the same, copy all, and then fixup */
2394 *new = *vma;
2395
Rik van Riel5beb4932010-03-05 13:42:07 -08002396 INIT_LIST_HEAD(&new->anon_vma_chain);
2397
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398 if (new_below)
2399 new->vm_end = addr;
2400 else {
2401 new->vm_start = addr;
2402 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2403 }
2404
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002405 err = vma_dup_policy(vma, new);
2406 if (err)
Rik van Riel5beb4932010-03-05 13:42:07 -08002407 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002408
Rik van Riel5beb4932010-03-05 13:42:07 -08002409 if (anon_vma_clone(new, vma))
2410 goto out_free_mpol;
2411
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002412 if (new->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002413 get_file(new->vm_file);
2414
2415 if (new->vm_ops && new->vm_ops->open)
2416 new->vm_ops->open(new);
2417
2418 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08002419 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07002420 ((addr - new->vm_start) >> PAGE_SHIFT), new);
2421 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002422 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002423
Rik van Riel5beb4932010-03-05 13:42:07 -08002424 /* Success. */
2425 if (!err)
2426 return 0;
2427
2428 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002429 if (new->vm_ops && new->vm_ops->close)
2430 new->vm_ops->close(new);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002431 if (new->vm_file)
Rik van Riel5beb4932010-03-05 13:42:07 -08002432 fput(new->vm_file);
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002433 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002434 out_free_mpol:
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002435 mpol_put(vma_policy(new));
Rik van Riel5beb4932010-03-05 13:42:07 -08002436 out_free_vma:
2437 kmem_cache_free(vm_area_cachep, new);
2438 out_err:
2439 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002440}
2441
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002442/*
2443 * Split a vma into two pieces at address 'addr', a new vma is allocated
2444 * either for the first part or the tail.
2445 */
2446int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2447 unsigned long addr, int new_below)
2448{
2449 if (mm->map_count >= sysctl_max_map_count)
2450 return -ENOMEM;
2451
2452 return __split_vma(mm, vma, addr, new_below);
2453}
2454
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455/* Munmap is split into 2 main parts -- this part which finds
2456 * what needs doing, and the areas themselves, which do the
2457 * work. This now handles partial unmappings.
2458 * Jeremy Fitzhardinge <jeremy@goop.org>
2459 */
2460int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2461{
2462 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002463 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002464
2465 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2466 return -EINVAL;
2467
2468 if ((len = PAGE_ALIGN(len)) == 0)
2469 return -EINVAL;
2470
2471 /* Find the first overlapping VMA */
Linus Torvalds9be34c92011-06-16 00:35:09 -07002472 vma = find_vma(mm, start);
Hugh Dickins146425a2005-04-19 13:29:18 -07002473 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002474 return 0;
Linus Torvalds9be34c92011-06-16 00:35:09 -07002475 prev = vma->vm_prev;
Hugh Dickins146425a2005-04-19 13:29:18 -07002476 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002477
2478 /* if it doesn't overlap, we have nothing.. */
2479 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002480 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002481 return 0;
2482
2483 /*
2484 * If we need to split any vma, do it now to save pain later.
2485 *
2486 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2487 * unmapped vm_area_struct will remain in use: so lower split_vma
2488 * places tmp vma above, and higher split_vma places tmp vma below.
2489 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002490 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002491 int error;
2492
2493 /*
2494 * Make sure that map_count on return from munmap() will
2495 * not exceed its limit; but let map_count go just above
2496 * its limit temporarily, to help free resources as expected.
2497 */
2498 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2499 return -ENOMEM;
2500
2501 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002502 if (error)
2503 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002504 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505 }
2506
2507 /* Does it split the last one? */
2508 last = find_vma(mm, end);
2509 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002510 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002511 if (error)
2512 return error;
2513 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002514 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002515
2516 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002517 * unlock any mlock()ed ranges before detaching vmas
2518 */
2519 if (mm->locked_vm) {
2520 struct vm_area_struct *tmp = vma;
2521 while (tmp && tmp->vm_start < end) {
2522 if (tmp->vm_flags & VM_LOCKED) {
2523 mm->locked_vm -= vma_pages(tmp);
2524 munlock_vma_pages_all(tmp);
2525 }
2526 tmp = tmp->vm_next;
2527 }
2528 }
2529
2530 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002531 * Remove the vma's, and unmap the actual pages
2532 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002533 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2534 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002535
2536 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002537 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002538
2539 return 0;
2540}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002541
Al Virobfce2812012-04-20 21:57:04 -04002542int vm_munmap(unsigned long start, size_t len)
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002543{
2544 int ret;
Al Virobfce2812012-04-20 21:57:04 -04002545 struct mm_struct *mm = current->mm;
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002546
2547 down_write(&mm->mmap_sem);
2548 ret = do_munmap(mm, start, len);
2549 up_write(&mm->mmap_sem);
2550 return ret;
2551}
2552EXPORT_SYMBOL(vm_munmap);
2553
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002554SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002555{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002556 profile_munmap(addr);
Al Virobfce2812012-04-20 21:57:04 -04002557 return vm_munmap(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002558}
2559
2560static inline void verify_mm_writelocked(struct mm_struct *mm)
2561{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002562#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002563 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2564 WARN_ON(1);
2565 up_read(&mm->mmap_sem);
2566 }
2567#endif
2568}
2569
2570/*
2571 * this is really a simplified "do_mmap". it only handles
2572 * anonymous maps. eventually we may be able to do some
2573 * brk-specific accounting here.
2574 */
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002575static unsigned long do_brk(unsigned long addr, unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002576{
2577 struct mm_struct * mm = current->mm;
2578 struct vm_area_struct * vma, * prev;
2579 unsigned long flags;
2580 struct rb_node ** rb_link, * rb_parent;
2581 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002582 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002583
2584 len = PAGE_ALIGN(len);
2585 if (!len)
2586 return addr;
2587
Kirill Korotaev3a459752006-09-07 14:17:04 +04002588 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2589
Al Viro2c6a1012009-12-03 19:40:46 -05002590 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2591 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002592 return error;
2593
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 /*
2595 * mlock MCL_FUTURE?
2596 */
2597 if (mm->def_flags & VM_LOCKED) {
2598 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002599 locked = len >> PAGE_SHIFT;
2600 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002601 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002602 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002603 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2604 return -EAGAIN;
2605 }
2606
2607 /*
2608 * mm->mmap_sem is required to protect against another thread
2609 * changing the mappings in case we sleep.
2610 */
2611 verify_mm_writelocked(mm);
2612
2613 /*
2614 * Clear old maps. this also does some error checking for us
2615 */
2616 munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07002617 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002618 if (do_munmap(mm, addr, len))
2619 return -ENOMEM;
2620 goto munmap_back;
2621 }
2622
2623 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002624 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002625 return -ENOMEM;
2626
2627 if (mm->map_count > sysctl_max_map_count)
2628 return -ENOMEM;
2629
Al Viro191c5422012-02-13 03:58:52 +00002630 if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 return -ENOMEM;
2632
Linus Torvalds1da177e2005-04-16 15:20:36 -07002633 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002634 vma = vma_merge(mm, prev, addr, addr + len, flags,
2635 NULL, NULL, pgoff, NULL);
2636 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002637 goto out;
2638
2639 /*
2640 * create a vma struct for an anonymous mapping
2641 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002642 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002643 if (!vma) {
2644 vm_unacct_memory(len >> PAGE_SHIFT);
2645 return -ENOMEM;
2646 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647
Rik van Riel5beb4932010-03-05 13:42:07 -08002648 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 vma->vm_mm = mm;
2650 vma->vm_start = addr;
2651 vma->vm_end = addr + len;
2652 vma->vm_pgoff = pgoff;
2653 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002654 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002655 vma_link(mm, vma, prev, rb_link, rb_parent);
2656out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002657 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002658 mm->total_vm += len >> PAGE_SHIFT;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002659 if (flags & VM_LOCKED)
2660 mm->locked_vm += (len >> PAGE_SHIFT);
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07002661 vma->vm_flags |= VM_SOFTDIRTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002662 return addr;
2663}
2664
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002665unsigned long vm_brk(unsigned long addr, unsigned long len)
2666{
2667 struct mm_struct *mm = current->mm;
2668 unsigned long ret;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002669 bool populate;
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002670
2671 down_write(&mm->mmap_sem);
2672 ret = do_brk(addr, len);
Michel Lespinasse128557f2013-02-22 16:32:40 -08002673 populate = ((mm->def_flags & VM_LOCKED) != 0);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002674 up_write(&mm->mmap_sem);
Michel Lespinasse128557f2013-02-22 16:32:40 -08002675 if (populate)
2676 mm_populate(addr, len);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002677 return ret;
2678}
2679EXPORT_SYMBOL(vm_brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680
2681/* Release all mmaps. */
2682void exit_mmap(struct mm_struct *mm)
2683{
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002684 struct mmu_gather tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002685 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002686 unsigned long nr_accounted = 0;
2687
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002688 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002689 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002690
Rik van Rielba470de2008-10-18 20:26:50 -07002691 if (mm->locked_vm) {
2692 vma = mm->mmap;
2693 while (vma) {
2694 if (vma->vm_flags & VM_LOCKED)
2695 munlock_vma_pages_all(vma);
2696 vma = vma->vm_next;
2697 }
2698 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002699
2700 arch_exit_mmap(mm);
2701
Rik van Rielba470de2008-10-18 20:26:50 -07002702 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002703 if (!vma) /* Can happen if dup_mmap() received an OOM */
2704 return;
2705
Linus Torvalds1da177e2005-04-16 15:20:36 -07002706 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002707 flush_cache_mm(mm);
Linus Torvalds2b047252013-08-15 11:42:25 -07002708 tlb_gather_mmu(&tlb, mm, 0, -1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002709 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002710 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002711 unmap_vmas(&tlb, vma, 0, -1);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002712
Hugh Dickins6ee86302013-04-29 15:07:44 -07002713 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING);
Al Viro853f5e22012-03-05 14:03:47 -05002714 tlb_finish_mmu(&tlb, 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002715
Linus Torvalds1da177e2005-04-16 15:20:36 -07002716 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002717 * Walk the list again, actually closing and freeing it,
2718 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002719 */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002720 while (vma) {
2721 if (vma->vm_flags & VM_ACCOUNT)
2722 nr_accounted += vma_pages(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002723 vma = remove_vma(vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002724 }
2725 vm_unacct_memory(nr_accounted);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002726
Kirill A. Shutemove1f56c82013-11-14 14:30:48 -08002727 WARN_ON(atomic_long_read(&mm->nr_ptes) >
2728 (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002729}
2730
2731/* Insert vm structure into process list sorted by address
2732 * and into the inode's i_mmap tree. If vm_file is non-NULL
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002733 * then i_mmap_mutex is taken here.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002734 */
Hugh Dickins6597d782012-10-08 16:29:07 -07002735int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002736{
Hugh Dickins6597d782012-10-08 16:29:07 -07002737 struct vm_area_struct *prev;
2738 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002739
2740 /*
2741 * The vm_pgoff of a purely anonymous vma should be irrelevant
2742 * until its first write fault, when page's anon_vma and index
2743 * are set. But now set the vm_pgoff it will almost certainly
2744 * end up with (unless mremap moves it elsewhere before that
2745 * first wfault), so /proc/pid/maps tells a consistent story.
2746 *
2747 * By setting it to reflect the virtual start address of the
2748 * vma, merges and splits can happen in a seamless way, just
2749 * using the existing file pgoff checks and manipulations.
2750 * Similarly in do_mmap_pgoff and in do_brk.
2751 */
2752 if (!vma->vm_file) {
2753 BUG_ON(vma->anon_vma);
2754 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2755 }
Hugh Dickins6597d782012-10-08 16:29:07 -07002756 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
2757 &prev, &rb_link, &rb_parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002758 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002759 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002760 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002761 return -ENOMEM;
Srikar Dronamraju2b144492012-02-09 14:56:42 +05302762
Linus Torvalds1da177e2005-04-16 15:20:36 -07002763 vma_link(mm, vma, prev, rb_link, rb_parent);
2764 return 0;
2765}
2766
2767/*
2768 * Copy the vma structure to a new location in the same mm,
2769 * prior to moving page table entries, to effect an mremap move.
2770 */
2771struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
Michel Lespinasse38a76012012-10-08 16:31:50 -07002772 unsigned long addr, unsigned long len, pgoff_t pgoff,
2773 bool *need_rmap_locks)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002774{
2775 struct vm_area_struct *vma = *vmap;
2776 unsigned long vma_start = vma->vm_start;
2777 struct mm_struct *mm = vma->vm_mm;
2778 struct vm_area_struct *new_vma, *prev;
2779 struct rb_node **rb_link, *rb_parent;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002780 bool faulted_in_anon_vma = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002781
2782 /*
2783 * If anonymous vma has not yet been faulted, update new pgoff
2784 * to match new location, to increase its chance of merging.
2785 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002786 if (unlikely(!vma->vm_file && !vma->anon_vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002787 pgoff = addr >> PAGE_SHIFT;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002788 faulted_in_anon_vma = false;
2789 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790
Hugh Dickins6597d782012-10-08 16:29:07 -07002791 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
2792 return NULL; /* should never get here */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002793 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2794 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2795 if (new_vma) {
2796 /*
2797 * Source vma may have been merged into new_vma
2798 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002799 if (unlikely(vma_start >= new_vma->vm_start &&
2800 vma_start < new_vma->vm_end)) {
2801 /*
2802 * The only way we can get a vma_merge with
2803 * self during an mremap is if the vma hasn't
2804 * been faulted in yet and we were allowed to
2805 * reset the dst vma->vm_pgoff to the
2806 * destination address of the mremap to allow
2807 * the merge to happen. mremap must change the
2808 * vm_pgoff linearity between src and dst vmas
2809 * (in turn preventing a vma_merge) to be
2810 * safe. It is only safe to keep the vm_pgoff
2811 * linear if there are no pages mapped yet.
2812 */
2813 VM_BUG_ON(faulted_in_anon_vma);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002814 *vmap = vma = new_vma;
Michel Lespinasse108d6642012-10-08 16:31:36 -07002815 }
Michel Lespinasse38a76012012-10-08 16:31:50 -07002816 *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002817 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002818 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002819 if (new_vma) {
2820 *new_vma = *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002821 new_vma->vm_start = addr;
2822 new_vma->vm_end = addr + len;
2823 new_vma->vm_pgoff = pgoff;
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002824 if (vma_dup_policy(vma, new_vma))
Michel Lespinasse523d4e22012-10-08 16:31:48 -07002825 goto out_free_vma;
Michel Lespinasse523d4e22012-10-08 16:31:48 -07002826 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2827 if (anon_vma_clone(new_vma, vma))
2828 goto out_free_mempol;
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002829 if (new_vma->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002830 get_file(new_vma->vm_file);
2831 if (new_vma->vm_ops && new_vma->vm_ops->open)
2832 new_vma->vm_ops->open(new_vma);
2833 vma_link(mm, new_vma, prev, rb_link, rb_parent);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002834 *need_rmap_locks = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002835 }
2836 }
2837 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002838
2839 out_free_mempol:
Oleg Nesterovef0855d2013-09-11 14:20:14 -07002840 mpol_put(vma_policy(new_vma));
Rik van Riel5beb4932010-03-05 13:42:07 -08002841 out_free_vma:
2842 kmem_cache_free(vm_area_cachep, new_vma);
2843 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002844}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002845
2846/*
2847 * Return true if the calling process may expand its vm space by the passed
2848 * number of pages
2849 */
2850int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2851{
2852 unsigned long cur = mm->total_vm; /* pages */
2853 unsigned long lim;
2854
Jiri Slaby59e99e52010-03-05 13:41:44 -08002855 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002856
2857 if (cur + npages > lim)
2858 return 0;
2859 return 1;
2860}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002861
2862
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002863static int special_mapping_fault(struct vm_area_struct *vma,
2864 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002865{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002866 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002867 struct page **pages;
2868
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002869 /*
2870 * special mappings have no vm_file, and in that case, the mm
2871 * uses vm_pgoff internally. So we have to subtract it from here.
2872 * We are allowed to do this because we are the mm; do not copy
2873 * this code into drivers!
2874 */
2875 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002876
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002877 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2878 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002879
2880 if (*pages) {
2881 struct page *page = *pages;
2882 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002883 vmf->page = page;
2884 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002885 }
2886
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002887 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002888}
2889
2890/*
2891 * Having a close hook prevents vma merging regardless of flags.
2892 */
2893static void special_mapping_close(struct vm_area_struct *vma)
2894{
2895}
2896
Alexey Dobriyanf0f37e2f2009-09-27 22:29:37 +04002897static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002898 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002899 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002900};
2901
2902/*
2903 * Called with mm->mmap_sem held for writing.
2904 * Insert a new vma covering the given region, with the given flags.
2905 * Its pages are supplied by the given array of struct page *.
2906 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2907 * The region past the last page supplied will always produce SIGBUS.
2908 * The array pointer and the pages it points to are assumed to stay alive
2909 * for as long as this mapping might exist.
2910 */
2911int install_special_mapping(struct mm_struct *mm,
2912 unsigned long addr, unsigned long len,
2913 unsigned long vm_flags, struct page **pages)
2914{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002915 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002916 struct vm_area_struct *vma;
2917
2918 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2919 if (unlikely(vma == NULL))
2920 return -ENOMEM;
2921
Rik van Riel5beb4932010-03-05 13:42:07 -08002922 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002923 vma->vm_mm = mm;
2924 vma->vm_start = addr;
2925 vma->vm_end = addr + len;
2926
Cyrill Gorcunovd9104d12013-09-11 14:22:24 -07002927 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY;
Coly Li3ed75eb2007-10-18 23:39:15 -07002928 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002929
2930 vma->vm_ops = &special_mapping_vmops;
2931 vma->vm_private_data = pages;
2932
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002933 ret = insert_vm_struct(mm, vma);
2934 if (ret)
2935 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002936
2937 mm->total_vm += len >> PAGE_SHIFT;
2938
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002939 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002940
Roland McGrathfa5dc222007-02-08 14:20:41 -08002941 return 0;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002942
2943out:
2944 kmem_cache_free(vm_area_cachep, vma);
2945 return ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002946}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002947
2948static DEFINE_MUTEX(mm_all_locks_mutex);
2949
Peter Zijlstra454ed842008-08-11 09:30:25 +02002950static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002951{
Michel Lespinassebf181b92012-10-08 16:31:39 -07002952 if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002953 /*
2954 * The LSB of head.next can't change from under us
2955 * because we hold the mm_all_locks_mutex.
2956 */
Jiri Kosina572043c2013-01-11 14:31:59 -08002957 down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002958 /*
2959 * We can safely modify head.next after taking the
Ingo Molnar5a505082012-12-02 19:56:46 +00002960 * anon_vma->root->rwsem. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002961 * the same anon_vma we won't take it again.
2962 *
2963 * No need of atomic instructions here, head.next
2964 * can't change from under us thanks to the
Ingo Molnar5a505082012-12-02 19:56:46 +00002965 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002966 */
2967 if (__test_and_set_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07002968 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002969 BUG();
2970 }
2971}
2972
Peter Zijlstra454ed842008-08-11 09:30:25 +02002973static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002974{
2975 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2976 /*
2977 * AS_MM_ALL_LOCKS can't change from under us because
2978 * we hold the mm_all_locks_mutex.
2979 *
2980 * Operations on ->flags have to be atomic because
2981 * even if AS_MM_ALL_LOCKS is stable thanks to the
2982 * mm_all_locks_mutex, there may be other cpus
2983 * changing other bitflags in parallel to us.
2984 */
2985 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2986 BUG();
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002987 mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002988 }
2989}
2990
2991/*
2992 * This operation locks against the VM for all pte/vma/mm related
2993 * operations that could ever happen on a certain mm. This includes
2994 * vmtruncate, try_to_unmap, and all page faults.
2995 *
2996 * The caller must take the mmap_sem in write mode before calling
2997 * mm_take_all_locks(). The caller isn't allowed to release the
2998 * mmap_sem until mm_drop_all_locks() returns.
2999 *
3000 * mmap_sem in write mode is required in order to block all operations
3001 * that could modify pagetables and free pages without need of
3002 * altering the vma layout (for example populate_range() with
3003 * nonlinear vmas). It's also needed in write mode to avoid new
3004 * anon_vmas to be associated with existing vmas.
3005 *
3006 * A single task can't take more than one mm_take_all_locks() in a row
3007 * or it would deadlock.
3008 *
Michel Lespinassebf181b92012-10-08 16:31:39 -07003009 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003010 * mapping->flags avoid to take the same lock twice, if more than one
3011 * vma in this mm is backed by the same anon_vma or address_space.
3012 *
3013 * We can take all the locks in random order because the VM code
Yuanhan Liu631b0cf2013-02-04 14:28:48 -08003014 * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003015 * takes more than one of them in a row. Secondly we're protected
3016 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
3017 *
3018 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
3019 * that may have to take thousand of locks.
3020 *
3021 * mm_take_all_locks() can fail if it's interrupted by signals.
3022 */
3023int mm_take_all_locks(struct mm_struct *mm)
3024{
3025 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003026 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003027
3028 BUG_ON(down_read_trylock(&mm->mmap_sem));
3029
3030 mutex_lock(&mm_all_locks_mutex);
3031
3032 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3033 if (signal_pending(current))
3034 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003035 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02003036 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003037 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003038
3039 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3040 if (signal_pending(current))
3041 goto out_unlock;
3042 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003043 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3044 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003045 }
3046
Kautuk Consul584cff52011-10-31 17:08:59 -07003047 return 0;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003048
3049out_unlock:
Kautuk Consul584cff52011-10-31 17:08:59 -07003050 mm_drop_all_locks(mm);
3051 return -EINTR;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003052}
3053
3054static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
3055{
Michel Lespinassebf181b92012-10-08 16:31:39 -07003056 if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003057 /*
3058 * The LSB of head.next can't change to 0 from under
3059 * us because we hold the mm_all_locks_mutex.
3060 *
3061 * We must however clear the bitflag before unlocking
Michel Lespinassebf181b92012-10-08 16:31:39 -07003062 * the vma so the users using the anon_vma->rb_root will
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003063 * never see our bitflag.
3064 *
3065 * No need of atomic instructions here, head.next
3066 * can't change from under us until we release the
Ingo Molnar5a505082012-12-02 19:56:46 +00003067 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003068 */
3069 if (!__test_and_clear_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07003070 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003071 BUG();
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08003072 anon_vma_unlock_write(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003073 }
3074}
3075
3076static void vm_unlock_mapping(struct address_space *mapping)
3077{
3078 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3079 /*
3080 * AS_MM_ALL_LOCKS can't change to 0 from under us
3081 * because we hold the mm_all_locks_mutex.
3082 */
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07003083 mutex_unlock(&mapping->i_mmap_mutex);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003084 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3085 &mapping->flags))
3086 BUG();
3087 }
3088}
3089
3090/*
3091 * The mmap_sem cannot be released by the caller until
3092 * mm_drop_all_locks() returns.
3093 */
3094void mm_drop_all_locks(struct mm_struct *mm)
3095{
3096 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003097 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003098
3099 BUG_ON(down_read_trylock(&mm->mmap_sem));
3100 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3101
3102 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3103 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003104 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3105 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003106 if (vma->vm_file && vma->vm_file->f_mapping)
3107 vm_unlock_mapping(vma->vm_file->f_mapping);
3108 }
3109
3110 mutex_unlock(&mm_all_locks_mutex);
3111}
David Howells8feae132009-01-08 12:04:47 +00003112
3113/*
3114 * initialise the VMA slab
3115 */
3116void __init mmap_init(void)
3117{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07003118 int ret;
3119
3120 ret = percpu_counter_init(&vm_committed_as, 0);
3121 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00003122}
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07003123
3124/*
3125 * Initialise sysctl_user_reserve_kbytes.
3126 *
3127 * This is intended to prevent a user from starting a single memory hogging
3128 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
3129 * mode.
3130 *
3131 * The default value is min(3% of free memory, 128MB)
3132 * 128MB is enough to recover with sshd/login, bash, and top/kill.
3133 */
Andrew Shewmaker16408792013-04-29 15:08:12 -07003134static int init_user_reserve(void)
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07003135{
3136 unsigned long free_kbytes;
3137
3138 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3139
3140 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
3141 return 0;
3142}
3143module_init(init_user_reserve)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07003144
3145/*
3146 * Initialise sysctl_admin_reserve_kbytes.
3147 *
3148 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
3149 * to log in and kill a memory hogging process.
3150 *
3151 * Systems with more than 256MB will reserve 8MB, enough to recover
3152 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
3153 * only reserve 3% of free pages by default.
3154 */
Andrew Shewmaker16408792013-04-29 15:08:12 -07003155static int init_admin_reserve(void)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07003156{
3157 unsigned long free_kbytes;
3158
3159 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3160
3161 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
3162 return 0;
3163}
3164module_init(init_admin_reserve)
Andrew Shewmaker16408792013-04-29 15:08:12 -07003165
3166/*
3167 * Reinititalise user and admin reserves if memory is added or removed.
3168 *
3169 * The default user reserve max is 128MB, and the default max for the
3170 * admin reserve is 8MB. These are usually, but not always, enough to
3171 * enable recovery from a memory hogging process using login/sshd, a shell,
3172 * and tools like top. It may make sense to increase or even disable the
3173 * reserve depending on the existence of swap or variations in the recovery
3174 * tools. So, the admin may have changed them.
3175 *
3176 * If memory is added and the reserves have been eliminated or increased above
3177 * the default max, then we'll trust the admin.
3178 *
3179 * If memory is removed and there isn't enough free memory, then we
3180 * need to reset the reserves.
3181 *
3182 * Otherwise keep the reserve set by the admin.
3183 */
3184static int reserve_mem_notifier(struct notifier_block *nb,
3185 unsigned long action, void *data)
3186{
3187 unsigned long tmp, free_kbytes;
3188
3189 switch (action) {
3190 case MEM_ONLINE:
3191 /* Default max is 128MB. Leave alone if modified by operator. */
3192 tmp = sysctl_user_reserve_kbytes;
3193 if (0 < tmp && tmp < (1UL << 17))
3194 init_user_reserve();
3195
3196 /* Default max is 8MB. Leave alone if modified by operator. */
3197 tmp = sysctl_admin_reserve_kbytes;
3198 if (0 < tmp && tmp < (1UL << 13))
3199 init_admin_reserve();
3200
3201 break;
3202 case MEM_OFFLINE:
3203 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
3204
3205 if (sysctl_user_reserve_kbytes > free_kbytes) {
3206 init_user_reserve();
3207 pr_info("vm.user_reserve_kbytes reset to %lu\n",
3208 sysctl_user_reserve_kbytes);
3209 }
3210
3211 if (sysctl_admin_reserve_kbytes > free_kbytes) {
3212 init_admin_reserve();
3213 pr_info("vm.admin_reserve_kbytes reset to %lu\n",
3214 sysctl_admin_reserve_kbytes);
3215 }
3216 break;
3217 default:
3218 break;
3219 }
3220 return NOTIFY_OK;
3221}
3222
3223static struct notifier_block reserve_mem_nb = {
3224 .notifier_call = reserve_mem_notifier,
3225};
3226
3227static int __meminit init_reserve_notifier(void)
3228{
3229 if (register_hotmemory_notifier(&reserve_mem_nb))
3230 printk("Failed registering memory add/remove notifier for admin reserve");
3231
3232 return 0;
3233}
3234module_init(init_reserve_notifier)