blob: 2664a47cec93721d6c73aafa85f32c11a5fb13e6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
Alan Cox046c6882009-01-05 14:06:29 +00006 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 */
8
9#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070010#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040025#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070029#include <linux/mmu_notifier.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020030#include <linux/perf_event.h>
Al Viro120a7952010-10-30 02:54:44 -040031#include <linux/audit.h>
Andrea Arcangelib15d00b2011-01-13 15:46:59 -080032#include <linux/khugepaged.h>
Srikar Dronamraju2b144492012-02-09 14:56:42 +053033#include <linux/uprobes.h>
Michel Lespinassed3737182012-12-11 16:01:38 -080034#include <linux/rbtree_augmented.h>
Clark Williamscf4aebc22013-02-07 09:46:59 -060035#include <linux/sched/sysctl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
37#include <asm/uaccess.h>
38#include <asm/cacheflush.h>
39#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020040#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
Jan Beulich42b77722008-07-23 21:27:10 -070042#include "internal.h"
43
Kirill Korotaev3a459752006-09-07 14:17:04 +040044#ifndef arch_mmap_check
45#define arch_mmap_check(addr, len, flags) (0)
46#endif
47
Martin Schwidefsky08e7d9b2008-02-04 22:29:16 -080048#ifndef arch_rebalance_pgtables
49#define arch_rebalance_pgtables(addr, len) (addr)
50#endif
51
Hugh Dickinse0da3822005-04-19 13:29:15 -070052static void unmap_region(struct mm_struct *mm,
53 struct vm_area_struct *vma, struct vm_area_struct *prev,
54 unsigned long start, unsigned long end);
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056/* description of effects of mapping type and prot in current implementation.
57 * this is due to the limited x86 page protection hardware. The expected
58 * behavior is in parens:
59 *
60 * map_type prot
61 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
62 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
63 * w: (no) no w: (no) no w: (yes) yes w: (no) no
64 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
65 *
66 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
67 * w: (no) no w: (no) no w: (copy) copy w: (no) no
68 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
69 *
70 */
71pgprot_t protection_map[16] = {
72 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
73 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
74};
75
Hugh Dickins804af2c2006-07-26 21:39:49 +010076pgprot_t vm_get_page_prot(unsigned long vm_flags)
77{
Dave Kleikampb845f312008-07-08 00:28:51 +100078 return __pgprot(pgprot_val(protection_map[vm_flags &
79 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
80 pgprot_val(arch_vm_get_page_prot(vm_flags)));
Hugh Dickins804af2c2006-07-26 21:39:49 +010081}
82EXPORT_SYMBOL(vm_get_page_prot);
83
Shaohua Li34679d72011-05-24 17:11:18 -070084int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */
85int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070086int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Shaohua Li34679d72011-05-24 17:11:18 -070087/*
88 * Make sure vm_committed_as in one cacheline and not cacheline shared with
89 * other variables. It can be updated by several CPUs frequently.
90 */
91struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
93/*
K. Y. Srinivasan997071b2012-11-15 14:34:42 -080094 * The global memory commitment made in the system can be a metric
95 * that can be used to drive ballooning decisions when Linux is hosted
96 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
97 * balancing memory across competing virtual machines that are hosted.
98 * Several metrics drive this policy engine including the guest reported
99 * memory commitment.
100 */
101unsigned long vm_memory_committed(void)
102{
103 return percpu_counter_read_positive(&vm_committed_as);
104}
105EXPORT_SYMBOL_GPL(vm_memory_committed);
106
107/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 * Check that a process has enough memory to allocate a new virtual
109 * mapping. 0 means there is enough memory for the allocation to
110 * succeed and -ENOMEM implies there is not.
111 *
112 * We currently support three overcommit policies, which are set via the
113 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
114 *
115 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
116 * Additional code 2002 Jul 20 by Robert Love.
117 *
118 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
119 *
120 * Note this is a helper function intended to be used by LSMs which
121 * wish to use this logic.
122 */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700123int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 unsigned long free, allowed;
126
127 vm_acct_memory(pages);
128
129 /*
130 * Sometimes we want to use more memory than we have
131 */
132 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
133 return 0;
134
135 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -0700136 free = global_page_state(NR_FREE_PAGES);
137 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
Dmitry Finkc15bef32011-07-25 17:12:19 -0700139 /*
140 * shmem pages shouldn't be counted as free in this
141 * case, they can't be purged, only swapped out, and
142 * that won't affect the overall amount of available
143 * memory in the system.
144 */
145 free -= global_page_state(NR_SHMEM);
146
Shaohua Liec8acf22013-02-22 16:34:38 -0800147 free += get_nr_swap_pages();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
149 /*
150 * Any slabs which are created with the
151 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
152 * which are reclaimable, under pressure. The dentry
153 * cache and most inode caches should fall into this
154 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700155 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
157 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -0700158 * Leave reserved pages. The pages are not for anonymous pages.
159 */
160 if (free <= totalreserve_pages)
161 goto error;
162 else
163 free -= totalreserve_pages;
164
165 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 * Leave the last 3% for root
167 */
168 if (!cap_sys_admin)
169 free -= free / 32;
170
171 if (free > pages)
172 return 0;
173
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700174 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 }
176
177 allowed = (totalram_pages - hugetlb_total_pages())
178 * sysctl_overcommit_ratio / 100;
179 /*
180 * Leave the last 3% for root
181 */
182 if (!cap_sys_admin)
183 allowed -= allowed / 32;
184 allowed += total_swap_pages;
185
186 /* Don't let a single process grow too big:
187 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -0700188 if (mm)
189 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700191 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700193error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 vm_unacct_memory(pages);
195
196 return -ENOMEM;
197}
198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199/*
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700200 * Requires inode->i_mapping->i_mmap_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 */
202static void __remove_shared_vm_struct(struct vm_area_struct *vma,
203 struct file *file, struct address_space *mapping)
204{
205 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500206 atomic_inc(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (vma->vm_flags & VM_SHARED)
208 mapping->i_mmap_writable--;
209
210 flush_dcache_mmap_lock(mapping);
211 if (unlikely(vma->vm_flags & VM_NONLINEAR))
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700212 list_del_init(&vma->shared.nonlinear);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700214 vma_interval_tree_remove(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 flush_dcache_mmap_unlock(mapping);
216}
217
218/*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700219 * Unlink a file-based vm structure from its interval tree, to hide
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700220 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700222void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223{
224 struct file *file = vma->vm_file;
225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 if (file) {
227 struct address_space *mapping = file->f_mapping;
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700228 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 __remove_shared_vm_struct(vma, file, mapping);
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700230 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700232}
233
234/*
235 * Close a vm structure and free it, returning the next.
236 */
237static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
238{
239 struct vm_area_struct *next = vma->vm_next;
240
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700241 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 if (vma->vm_ops && vma->vm_ops->close)
243 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700244 if (vma->vm_file)
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700245 fput(vma->vm_file);
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700246 mpol_put(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700248 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249}
250
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -0700251static unsigned long do_brk(unsigned long addr, unsigned long len);
252
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100253SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254{
255 unsigned long rlim, retval;
256 unsigned long newbrk, oldbrk;
257 struct mm_struct *mm = current->mm;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700258 unsigned long min_brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800259 bool populate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 down_write(&mm->mmap_sem);
262
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700263#ifdef CONFIG_COMPAT_BRK
Jiri Kosina5520e892011-01-13 15:47:23 -0800264 /*
265 * CONFIG_COMPAT_BRK can still be overridden by setting
266 * randomize_va_space to 2, which will still cause mm->start_brk
267 * to be arbitrarily shifted
268 */
Jiri Kosina4471a672011-04-14 15:22:09 -0700269 if (current->brk_randomized)
Jiri Kosina5520e892011-01-13 15:47:23 -0800270 min_brk = mm->start_brk;
271 else
272 min_brk = mm->end_data;
Jiri Kosinaa5b45922008-06-05 22:46:05 -0700273#else
274 min_brk = mm->start_brk;
275#endif
276 if (brk < min_brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700278
279 /*
280 * Check against rlimit here. If this check is done later after the test
281 * of oldbrk with newbrk then it can escape the test and let the data
282 * segment grow beyond its set limit the in case where the limit is
283 * not page aligned -Ram Gupta
284 */
Jiri Slaby59e99e52010-03-05 13:41:44 -0800285 rlim = rlimit(RLIMIT_DATA);
Jiri Kosinac1d171a2008-01-30 13:30:40 +0100286 if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
287 (mm->end_data - mm->start_data) > rlim)
Ram Gupta1e624192006-04-10 22:52:57 -0700288 goto out;
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 newbrk = PAGE_ALIGN(brk);
291 oldbrk = PAGE_ALIGN(mm->brk);
292 if (oldbrk == newbrk)
293 goto set_brk;
294
295 /* Always allow shrinking brk. */
296 if (brk <= mm->brk) {
297 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
298 goto set_brk;
299 goto out;
300 }
301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 /* Check against existing mmap mappings. */
303 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
304 goto out;
305
306 /* Ok, looks good - let it rip. */
307 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
308 goto out;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800309
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310set_brk:
311 mm->brk = brk;
Michel Lespinasse128557f2013-02-22 16:32:40 -0800312 populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0;
313 up_write(&mm->mmap_sem);
314 if (populate)
315 mm_populate(oldbrk, newbrk - oldbrk);
316 return brk;
317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318out:
319 retval = mm->brk;
320 up_write(&mm->mmap_sem);
321 return retval;
322}
323
Michel Lespinassed3737182012-12-11 16:01:38 -0800324static long vma_compute_subtree_gap(struct vm_area_struct *vma)
325{
326 unsigned long max, subtree_gap;
327 max = vma->vm_start;
328 if (vma->vm_prev)
329 max -= vma->vm_prev->vm_end;
330 if (vma->vm_rb.rb_left) {
331 subtree_gap = rb_entry(vma->vm_rb.rb_left,
332 struct vm_area_struct, vm_rb)->rb_subtree_gap;
333 if (subtree_gap > max)
334 max = subtree_gap;
335 }
336 if (vma->vm_rb.rb_right) {
337 subtree_gap = rb_entry(vma->vm_rb.rb_right,
338 struct vm_area_struct, vm_rb)->rb_subtree_gap;
339 if (subtree_gap > max)
340 max = subtree_gap;
341 }
342 return max;
343}
344
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700345#ifdef CONFIG_DEBUG_VM_RB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346static int browse_rb(struct rb_root *root)
347{
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800348 int i = 0, j, bug = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 struct rb_node *nd, *pn = NULL;
350 unsigned long prev = 0, pend = 0;
351
352 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
353 struct vm_area_struct *vma;
354 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800355 if (vma->vm_start < prev) {
356 printk("vm_start %lx prev %lx\n", vma->vm_start, prev);
357 bug = 1;
358 }
359 if (vma->vm_start < pend) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800361 bug = 1;
362 }
363 if (vma->vm_start > vma->vm_end) {
364 printk("vm_end %lx < vm_start %lx\n",
365 vma->vm_end, vma->vm_start);
366 bug = 1;
367 }
368 if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
369 printk("free gap %lx, correct %lx\n",
370 vma->rb_subtree_gap,
371 vma_compute_subtree_gap(vma));
372 bug = 1;
373 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 i++;
375 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800376 prev = vma->vm_start;
377 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 }
379 j = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800380 for (nd = pn; nd; nd = rb_prev(nd))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 j++;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800382 if (i != j) {
383 printk("backwards %d, forwards %d\n", j, i);
384 bug = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800386 return bug ? -1 : i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387}
388
Michel Lespinassed3737182012-12-11 16:01:38 -0800389static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
390{
391 struct rb_node *nd;
392
393 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
394 struct vm_area_struct *vma;
395 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
396 BUG_ON(vma != ignore &&
397 vma->rb_subtree_gap != vma_compute_subtree_gap(vma));
398 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399}
400
401void validate_mm(struct mm_struct *mm)
402{
403 int bug = 0;
404 int i = 0;
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800405 unsigned long highest_address = 0;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700406 struct vm_area_struct *vma = mm->mmap;
407 while (vma) {
408 struct anon_vma_chain *avc;
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800409 vma_lock_anon_vma(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700410 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
411 anon_vma_interval_tree_verify(avc);
Michel Lespinasse63c3b902012-11-16 14:14:47 -0800412 vma_unlock_anon_vma(vma);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800413 highest_address = vma->vm_end;
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700414 vma = vma->vm_next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 i++;
416 }
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800417 if (i != mm->map_count) {
418 printk("map_count %d vm_next %d\n", mm->map_count, i);
419 bug = 1;
420 }
421 if (highest_address != mm->highest_vm_end) {
422 printk("mm->highest_vm_end %lx, found %lx\n",
423 mm->highest_vm_end, highest_address);
424 bug = 1;
425 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 i = browse_rb(&mm->mm_rb);
Michel Lespinasse5a0768f2012-12-11 16:01:42 -0800427 if (i != mm->map_count) {
428 printk("map_count %d rb %d\n", mm->map_count, i);
429 bug = 1;
430 }
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200431 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432}
433#else
Michel Lespinassed3737182012-12-11 16:01:38 -0800434#define validate_mm_rb(root, ignore) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435#define validate_mm(mm) do { } while (0)
436#endif
437
Michel Lespinassed3737182012-12-11 16:01:38 -0800438RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb,
439 unsigned long, rb_subtree_gap, vma_compute_subtree_gap)
440
441/*
442 * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
443 * vma->vm_prev->vm_end values changed, without modifying the vma's position
444 * in the rbtree.
445 */
446static void vma_gap_update(struct vm_area_struct *vma)
447{
448 /*
449 * As it turns out, RB_DECLARE_CALLBACKS() already created a callback
450 * function that does exacltly what we want.
451 */
452 vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
453}
454
455static inline void vma_rb_insert(struct vm_area_struct *vma,
456 struct rb_root *root)
457{
458 /* All rb_subtree_gap values must be consistent prior to insertion */
459 validate_mm_rb(root, NULL);
460
461 rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
462}
463
464static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
465{
466 /*
467 * All rb_subtree_gap values must be consistent prior to erase,
468 * with the possible exception of the vma being erased.
469 */
470 validate_mm_rb(root, vma);
471
472 /*
473 * Note rb_erase_augmented is a fairly large inline function,
474 * so make sure we instantiate it only once with our desired
475 * augmented rbtree callbacks.
476 */
477 rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
478}
479
Michel Lespinassebf181b92012-10-08 16:31:39 -0700480/*
481 * vma has some anon_vma assigned, and is already inserted on that
482 * anon_vma's interval trees.
483 *
484 * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the
485 * vma must be removed from the anon_vma's interval trees using
486 * anon_vma_interval_tree_pre_update_vma().
487 *
488 * After the update, the vma will be reinserted using
489 * anon_vma_interval_tree_post_update_vma().
490 *
491 * The entire update must be protected by exclusive mmap_sem and by
492 * the root anon_vma's mutex.
493 */
494static inline void
495anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma)
496{
497 struct anon_vma_chain *avc;
498
499 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
500 anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root);
501}
502
503static inline void
504anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
505{
506 struct anon_vma_chain *avc;
507
508 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
509 anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
510}
511
Hugh Dickins6597d782012-10-08 16:29:07 -0700512static int find_vma_links(struct mm_struct *mm, unsigned long addr,
513 unsigned long end, struct vm_area_struct **pprev,
514 struct rb_node ***rb_link, struct rb_node **rb_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515{
Hugh Dickins6597d782012-10-08 16:29:07 -0700516 struct rb_node **__rb_link, *__rb_parent, *rb_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517
518 __rb_link = &mm->mm_rb.rb_node;
519 rb_prev = __rb_parent = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
521 while (*__rb_link) {
522 struct vm_area_struct *vma_tmp;
523
524 __rb_parent = *__rb_link;
525 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
526
527 if (vma_tmp->vm_end > addr) {
Hugh Dickins6597d782012-10-08 16:29:07 -0700528 /* Fail if an existing vma overlaps the area */
529 if (vma_tmp->vm_start < end)
530 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 __rb_link = &__rb_parent->rb_left;
532 } else {
533 rb_prev = __rb_parent;
534 __rb_link = &__rb_parent->rb_right;
535 }
536 }
537
538 *pprev = NULL;
539 if (rb_prev)
540 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
541 *rb_link = __rb_link;
542 *rb_parent = __rb_parent;
Hugh Dickins6597d782012-10-08 16:29:07 -0700543 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544}
545
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
547 struct rb_node **rb_link, struct rb_node *rb_parent)
548{
Michel Lespinassed3737182012-12-11 16:01:38 -0800549 /* Update tracking information for the gap following the new vma. */
550 if (vma->vm_next)
551 vma_gap_update(vma->vm_next);
552 else
553 mm->highest_vm_end = vma->vm_end;
554
555 /*
556 * vma->vm_prev wasn't known when we followed the rbtree to find the
557 * correct insertion point for that vma. As a result, we could not
558 * update the vma vm_rb parents rb_subtree_gap values on the way down.
559 * So, we first insert the vma with a zero rb_subtree_gap value
560 * (to be consistent with what we did on the way down), and then
561 * immediately update the gap to the correct value. Finally we
562 * rebalance the rbtree after all augmented values have been set.
563 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
Michel Lespinassed3737182012-12-11 16:01:38 -0800565 vma->rb_subtree_gap = 0;
566 vma_gap_update(vma);
567 vma_rb_insert(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568}
569
Denys Vlasenkocb8f4882008-10-18 20:27:01 -0700570static void __vma_link_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571{
ZhenwenXu48aae422009-01-06 14:40:21 -0800572 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573
574 file = vma->vm_file;
575 if (file) {
576 struct address_space *mapping = file->f_mapping;
577
578 if (vma->vm_flags & VM_DENYWRITE)
Al Viro496ad9a2013-01-23 17:07:38 -0500579 atomic_dec(&file_inode(file)->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 if (vma->vm_flags & VM_SHARED)
581 mapping->i_mmap_writable++;
582
583 flush_dcache_mmap_lock(mapping);
584 if (unlikely(vma->vm_flags & VM_NONLINEAR))
585 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
586 else
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700587 vma_interval_tree_insert(vma, &mapping->i_mmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 flush_dcache_mmap_unlock(mapping);
589 }
590}
591
592static void
593__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
594 struct vm_area_struct *prev, struct rb_node **rb_link,
595 struct rb_node *rb_parent)
596{
597 __vma_link_list(mm, vma, prev, rb_parent);
598 __vma_link_rb(mm, vma, rb_link, rb_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599}
600
601static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
602 struct vm_area_struct *prev, struct rb_node **rb_link,
603 struct rb_node *rb_parent)
604{
605 struct address_space *mapping = NULL;
606
607 if (vma->vm_file)
608 mapping = vma->vm_file->f_mapping;
609
Peter Zijlstra97a89412011-05-24 17:12:04 -0700610 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700611 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612
613 __vma_link(mm, vma, prev, rb_link, rb_parent);
614 __vma_link_file(vma);
615
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700617 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
619 mm->map_count++;
620 validate_mm(mm);
621}
622
623/*
Kautuk Consul88f6b4c2012-03-21 16:34:16 -0700624 * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700625 * mm's list and rbtree. It has already been inserted into the interval tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 */
ZhenwenXu48aae422009-01-06 14:40:21 -0800627static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628{
Hugh Dickins6597d782012-10-08 16:29:07 -0700629 struct vm_area_struct *prev;
ZhenwenXu48aae422009-01-06 14:40:21 -0800630 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
Hugh Dickins6597d782012-10-08 16:29:07 -0700632 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
633 &prev, &rb_link, &rb_parent))
634 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 __vma_link(mm, vma, prev, rb_link, rb_parent);
636 mm->map_count++;
637}
638
639static inline void
640__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
641 struct vm_area_struct *prev)
642{
Michel Lespinassed3737182012-12-11 16:01:38 -0800643 struct vm_area_struct *next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700644
Michel Lespinassed3737182012-12-11 16:01:38 -0800645 vma_rb_erase(vma, &mm->mm_rb);
646 prev->vm_next = next = vma->vm_next;
Linus Torvalds297c5ee2010-08-20 16:24:55 -0700647 if (next)
648 next->vm_prev = prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 if (mm->mmap_cache == vma)
650 mm->mmap_cache = prev;
651}
652
653/*
654 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
655 * is already present in an i_mmap tree without adjusting the tree.
656 * The following helper function should be used when such adjustments
657 * are necessary. The "insert" vma (if any) is to be inserted
658 * before we drop the necessary locks.
659 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800660int vma_adjust(struct vm_area_struct *vma, unsigned long start,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
662{
663 struct mm_struct *mm = vma->vm_mm;
664 struct vm_area_struct *next = vma->vm_next;
665 struct vm_area_struct *importer = NULL;
666 struct address_space *mapping = NULL;
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700667 struct rb_root *root = NULL;
Rik van Riel012f18002010-08-09 17:18:40 -0700668 struct anon_vma *anon_vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 struct file *file = vma->vm_file;
Michel Lespinassed3737182012-12-11 16:01:38 -0800670 bool start_changed = false, end_changed = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 long adjust_next = 0;
672 int remove_next = 0;
673
674 if (next && !insert) {
Linus Torvalds287d97a2010-04-10 15:22:30 -0700675 struct vm_area_struct *exporter = NULL;
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 if (end >= next->vm_end) {
678 /*
679 * vma expands, overlapping all the next, and
680 * perhaps the one after too (mprotect case 6).
681 */
682again: remove_next = 1 + (end > next->vm_end);
683 end = next->vm_end;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700684 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 importer = vma;
686 } else if (end > next->vm_start) {
687 /*
688 * vma expands, overlapping part of the next:
689 * mprotect case 5 shifting the boundary up.
690 */
691 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700692 exporter = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 importer = vma;
694 } else if (end < vma->vm_end) {
695 /*
696 * vma shrinks, and !insert tells it's not
697 * split_vma inserting another: so it must be
698 * mprotect case 4 shifting the boundary down.
699 */
700 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
Linus Torvalds287d97a2010-04-10 15:22:30 -0700701 exporter = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 importer = next;
703 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704
Rik van Riel5beb4932010-03-05 13:42:07 -0800705 /*
706 * Easily overlooked: when mprotect shifts the boundary,
707 * make sure the expanding vma has anon_vma set if the
708 * shrinking vma had, to cover any anon pages imported.
709 */
Linus Torvalds287d97a2010-04-10 15:22:30 -0700710 if (exporter && exporter->anon_vma && !importer->anon_vma) {
711 if (anon_vma_clone(importer, exporter))
Rik van Riel5beb4932010-03-05 13:42:07 -0800712 return -ENOMEM;
Linus Torvalds287d97a2010-04-10 15:22:30 -0700713 importer->anon_vma = exporter->anon_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -0800714 }
715 }
716
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 if (file) {
718 mapping = file->f_mapping;
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530719 if (!(vma->vm_flags & VM_NONLINEAR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 root = &mapping->i_mmap;
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530721 uprobe_munmap(vma, vma->vm_start, vma->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530722
723 if (adjust_next)
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530724 uprobe_munmap(next, next->vm_start,
725 next->vm_end);
Srikar Dronamraju682968e2012-03-30 23:56:46 +0530726 }
727
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700728 mutex_lock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 if (insert) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 /*
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700731 * Put into interval tree now, so instantiated pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 * are visible to arm/parisc __flush_dcache_page
733 * throughout; but we cannot insert into address
734 * space until vma start or end is updated.
735 */
736 __vma_link_file(insert);
737 }
738 }
739
Andrea Arcangeli94fcc582011-01-13 15:47:08 -0800740 vma_adjust_trans_huge(vma, start, end, adjust_next);
741
Michel Lespinassebf181b92012-10-08 16:31:39 -0700742 anon_vma = vma->anon_vma;
743 if (!anon_vma && adjust_next)
744 anon_vma = next->anon_vma;
745 if (anon_vma) {
Michel Lespinasseca42b262012-10-08 16:30:01 -0700746 VM_BUG_ON(adjust_next && next->anon_vma &&
747 anon_vma != next->anon_vma);
Ingo Molnar4fc3f1d2012-12-02 19:56:50 +0000748 anon_vma_lock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700749 anon_vma_interval_tree_pre_update_vma(vma);
750 if (adjust_next)
751 anon_vma_interval_tree_pre_update_vma(next);
752 }
Rik van Riel012f18002010-08-09 17:18:40 -0700753
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 if (root) {
755 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700756 vma_interval_tree_remove(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700758 vma_interval_tree_remove(next, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 }
760
Michel Lespinassed3737182012-12-11 16:01:38 -0800761 if (start != vma->vm_start) {
762 vma->vm_start = start;
763 start_changed = true;
764 }
765 if (end != vma->vm_end) {
766 vma->vm_end = end;
767 end_changed = true;
768 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 vma->vm_pgoff = pgoff;
770 if (adjust_next) {
771 next->vm_start += adjust_next << PAGE_SHIFT;
772 next->vm_pgoff += adjust_next;
773 }
774
775 if (root) {
776 if (adjust_next)
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700777 vma_interval_tree_insert(next, root);
778 vma_interval_tree_insert(vma, root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 flush_dcache_mmap_unlock(mapping);
780 }
781
782 if (remove_next) {
783 /*
784 * vma_merge has merged next into vma, and needs
785 * us to remove next before dropping the locks.
786 */
787 __vma_unlink(mm, next, vma);
788 if (file)
789 __remove_shared_vm_struct(next, file, mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 } else if (insert) {
791 /*
792 * split_vma has split insert from vma, and needs
793 * us to insert it before dropping the locks
794 * (it may either follow vma or precede it).
795 */
796 __insert_vm_struct(mm, insert);
Michel Lespinassed3737182012-12-11 16:01:38 -0800797 } else {
798 if (start_changed)
799 vma_gap_update(vma);
800 if (end_changed) {
801 if (!next)
802 mm->highest_vm_end = end;
803 else if (!adjust_next)
804 vma_gap_update(next);
805 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 }
807
Michel Lespinassebf181b92012-10-08 16:31:39 -0700808 if (anon_vma) {
809 anon_vma_interval_tree_post_update_vma(vma);
810 if (adjust_next)
811 anon_vma_interval_tree_post_update_vma(next);
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -0800812 anon_vma_unlock_write(anon_vma);
Michel Lespinassebf181b92012-10-08 16:31:39 -0700813 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 if (mapping)
Peter Zijlstra3d48ae42011-05-24 17:12:06 -0700815 mutex_unlock(&mapping->i_mmap_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530817 if (root) {
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100818 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530819
820 if (adjust_next)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100821 uprobe_mmap(next);
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530822 }
823
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 if (remove_next) {
Matt Helsley925d1c42008-04-29 01:01:36 -0700825 if (file) {
Srikar Dronamrajucbc91f72012-04-11 16:05:27 +0530826 uprobe_munmap(next, next->vm_start, next->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 fput(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700828 }
Rik van Riel5beb4932010-03-05 13:42:07 -0800829 if (next->anon_vma)
830 anon_vma_merge(vma, next);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 mm->map_count--;
Lee Schermerhornf0be3d32008-04-28 02:13:08 -0700832 mpol_put(vma_policy(next));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 kmem_cache_free(vm_area_cachep, next);
834 /*
835 * In mprotect's case 6 (see comments on vma_merge),
836 * we must remove another next too. It would clutter
837 * up the code too much to do both in one go.
838 */
Michel Lespinassed3737182012-12-11 16:01:38 -0800839 next = vma->vm_next;
840 if (remove_next == 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 goto again;
Michel Lespinassed3737182012-12-11 16:01:38 -0800842 else if (next)
843 vma_gap_update(next);
844 else
845 mm->highest_vm_end = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530847 if (insert && file)
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100848 uprobe_mmap(insert);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849
850 validate_mm(mm);
Rik van Riel5beb4932010-03-05 13:42:07 -0800851
852 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853}
854
855/*
856 * If the vma has a ->close operation then the driver probably needs to release
857 * per-vma resources, so we don't attempt to merge those.
858 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859static inline int is_mergeable_vma(struct vm_area_struct *vma,
860 struct file *file, unsigned long vm_flags)
861{
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -0700862 if (vma->vm_flags ^ vm_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 return 0;
864 if (vma->vm_file != file)
865 return 0;
866 if (vma->vm_ops && vma->vm_ops->close)
867 return 0;
868 return 1;
869}
870
871static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
Shaohua Li965f55d2011-05-24 17:11:20 -0700872 struct anon_vma *anon_vma2,
873 struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874{
Shaohua Li965f55d2011-05-24 17:11:20 -0700875 /*
876 * The list_is_singular() test is to avoid merging VMA cloned from
877 * parents. This can improve scalability caused by anon_vma lock.
878 */
879 if ((!anon_vma1 || !anon_vma2) && (!vma ||
880 list_is_singular(&vma->anon_vma_chain)))
881 return 1;
882 return anon_vma1 == anon_vma2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883}
884
885/*
886 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
887 * in front of (at a lower virtual address and file offset than) the vma.
888 *
889 * We cannot merge two vmas if they have differently assigned (non-NULL)
890 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
891 *
892 * We don't check here for the merged mmap wrapping around the end of pagecache
893 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
894 * wrap, nor mmaps which cover the final page at index -1UL.
895 */
896static int
897can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
898 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
899{
900 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700901 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 if (vma->vm_pgoff == vm_pgoff)
903 return 1;
904 }
905 return 0;
906}
907
908/*
909 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
910 * beyond (at a higher virtual address and file offset than) the vma.
911 *
912 * We cannot merge two vmas if they have differently assigned (non-NULL)
913 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
914 */
915static int
916can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
917 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
918{
919 if (is_mergeable_vma(vma, file, vm_flags) &&
Shaohua Li965f55d2011-05-24 17:11:20 -0700920 is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 pgoff_t vm_pglen;
922 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
923 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
924 return 1;
925 }
926 return 0;
927}
928
929/*
930 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
931 * whether that can be merged with its predecessor or its successor.
932 * Or both (it neatly fills a hole).
933 *
934 * In most cases - when called for mmap, brk or mremap - [addr,end) is
935 * certain not to be mapped by the time vma_merge is called; but when
936 * called for mprotect, it is certain to be already mapped (either at
937 * an offset within prev, or at the start of next), and the flags of
938 * this area are about to be changed to vm_flags - and the no-change
939 * case has already been eliminated.
940 *
941 * The following mprotect cases have to be considered, where AAAA is
942 * the area passed down from mprotect_fixup, never extending beyond one
943 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
944 *
945 * AAAA AAAA AAAA AAAA
946 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
947 * cannot merge might become might become might become
948 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
949 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
950 * mremap move: PPPPNNNNNNNN 8
951 * AAAA
952 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
953 * might become case 1 below case 2 below case 3 below
954 *
955 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
956 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
957 */
958struct vm_area_struct *vma_merge(struct mm_struct *mm,
959 struct vm_area_struct *prev, unsigned long addr,
960 unsigned long end, unsigned long vm_flags,
961 struct anon_vma *anon_vma, struct file *file,
962 pgoff_t pgoff, struct mempolicy *policy)
963{
964 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
965 struct vm_area_struct *area, *next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800966 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
968 /*
969 * We later require that vma->vm_flags == vm_flags,
970 * so this tests vma->vm_flags & VM_SPECIAL, too.
971 */
972 if (vm_flags & VM_SPECIAL)
973 return NULL;
974
975 if (prev)
976 next = prev->vm_next;
977 else
978 next = mm->mmap;
979 area = next;
980 if (next && next->vm_end == end) /* cases 6, 7, 8 */
981 next = next->vm_next;
982
983 /*
984 * Can it merge with the predecessor?
985 */
986 if (prev && prev->vm_end == addr &&
987 mpol_equal(vma_policy(prev), policy) &&
988 can_vma_merge_after(prev, vm_flags,
989 anon_vma, file, pgoff)) {
990 /*
991 * OK, it can. Can we now merge in the successor as well?
992 */
993 if (next && end == next->vm_start &&
994 mpol_equal(policy, vma_policy(next)) &&
995 can_vma_merge_before(next, vm_flags,
996 anon_vma, file, pgoff+pglen) &&
997 is_mergeable_anon_vma(prev->anon_vma,
Shaohua Li965f55d2011-05-24 17:11:20 -0700998 next->anon_vma, NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 /* cases 1, 6 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001000 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 next->vm_end, prev->vm_pgoff, NULL);
1002 } else /* cases 2, 5, 7 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001003 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 end, prev->vm_pgoff, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001005 if (err)
1006 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001007 khugepaged_enter_vma_merge(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 return prev;
1009 }
1010
1011 /*
1012 * Can this new request be merged in front of next?
1013 */
1014 if (next && end == next->vm_start &&
1015 mpol_equal(policy, vma_policy(next)) &&
1016 can_vma_merge_before(next, vm_flags,
1017 anon_vma, file, pgoff+pglen)) {
1018 if (prev && addr < prev->vm_end) /* case 4 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001019 err = vma_adjust(prev, prev->vm_start,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 addr, prev->vm_pgoff, NULL);
1021 else /* cases 3, 8 */
Rik van Riel5beb4932010-03-05 13:42:07 -08001022 err = vma_adjust(area, addr, next->vm_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 next->vm_pgoff - pglen, NULL);
Rik van Riel5beb4932010-03-05 13:42:07 -08001024 if (err)
1025 return NULL;
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08001026 khugepaged_enter_vma_merge(area);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027 return area;
1028 }
1029
1030 return NULL;
1031}
1032
1033/*
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001034 * Rough compatbility check to quickly see if it's even worth looking
1035 * at sharing an anon_vma.
1036 *
1037 * They need to have the same vm_file, and the flags can only differ
1038 * in things that mprotect may change.
1039 *
1040 * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that
1041 * we can merge the two vma's. For example, we refuse to merge a vma if
1042 * there is a vm_ops->close() function, because that indicates that the
1043 * driver is doing some kind of reference counting. But that doesn't
1044 * really matter for the anon_vma sharing case.
1045 */
1046static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b)
1047{
1048 return a->vm_end == b->vm_start &&
1049 mpol_equal(vma_policy(a), vma_policy(b)) &&
1050 a->vm_file == b->vm_file &&
1051 !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) &&
1052 b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
1053}
1054
1055/*
1056 * Do some basic sanity checking to see if we can re-use the anon_vma
1057 * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be
1058 * the same as 'old', the other will be the new one that is trying
1059 * to share the anon_vma.
1060 *
1061 * NOTE! This runs with mm_sem held for reading, so it is possible that
1062 * the anon_vma of 'old' is concurrently in the process of being set up
1063 * by another page fault trying to merge _that_. But that's ok: if it
1064 * is being set up, that automatically means that it will be a singleton
1065 * acceptable for merging, so we can do all of this optimistically. But
1066 * we do that ACCESS_ONCE() to make sure that we never re-load the pointer.
1067 *
1068 * IOW: that the "list_is_singular()" test on the anon_vma_chain only
1069 * matters for the 'stable anon_vma' case (ie the thing we want to avoid
1070 * is to return an anon_vma that is "complex" due to having gone through
1071 * a fork).
1072 *
1073 * We also make sure that the two vma's are compatible (adjacent,
1074 * and with the same memory policies). That's all stable, even with just
1075 * a read lock on the mm_sem.
1076 */
1077static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b)
1078{
1079 if (anon_vma_compatible(a, b)) {
1080 struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma);
1081
1082 if (anon_vma && list_is_singular(&old->anon_vma_chain))
1083 return anon_vma;
1084 }
1085 return NULL;
1086}
1087
1088/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
1090 * neighbouring vmas for a suitable anon_vma, before it goes off
1091 * to allocate a new anon_vma. It checks because a repetitive
1092 * sequence of mprotects and faults may otherwise lead to distinct
1093 * anon_vmas being allocated, preventing vma merge in subsequent
1094 * mprotect.
1095 */
1096struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
1097{
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001098 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 struct vm_area_struct *near;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100
1101 near = vma->vm_next;
1102 if (!near)
1103 goto try_prev;
1104
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001105 anon_vma = reusable_anon_vma(near, vma, near);
1106 if (anon_vma)
1107 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108try_prev:
Linus Torvalds9be34c92011-06-16 00:35:09 -07001109 near = vma->vm_prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 if (!near)
1111 goto none;
1112
Linus Torvaldsd0e9fe12010-04-10 10:36:19 -07001113 anon_vma = reusable_anon_vma(near, near, vma);
1114 if (anon_vma)
1115 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116none:
1117 /*
1118 * There's no absolute need to look only at touching neighbours:
1119 * we could search further afield for "compatible" anon_vmas.
1120 * But it would probably just be a waste of time searching,
1121 * or lead to too many vmas hanging off the same anon_vma.
1122 * We're trying to allow mprotect remerging later on,
1123 * not trying to minimize memory used for anon_vmas.
1124 */
1125 return NULL;
1126}
1127
1128#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001129void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 struct file *file, long pages)
1131{
1132 const unsigned long stack_flags
1133 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
1134
Huang Shijie44de9d02012-07-31 16:41:49 -07001135 mm->total_vm += pages;
1136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 if (file) {
1138 mm->shared_vm += pages;
1139 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
1140 mm->exec_vm += pages;
1141 } else if (flags & stack_flags)
1142 mm->stack_vm += pages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143}
1144#endif /* CONFIG_PROC_FS */
1145
1146/*
Al Viro40401532012-02-13 03:58:52 +00001147 * If a hint addr is less than mmap_min_addr change hint to be as
1148 * low as possible but still greater than mmap_min_addr
1149 */
1150static inline unsigned long round_hint_to_min(unsigned long hint)
1151{
1152 hint &= PAGE_MASK;
1153 if (((void *)hint != NULL) &&
1154 (hint < mmap_min_addr))
1155 return PAGE_ALIGN(mmap_min_addr);
1156 return hint;
1157}
1158
1159/*
Jianjun Kong27f5de72009-09-17 19:26:26 -07001160 * The caller must hold down_write(&current->mm->mmap_sem).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 */
1162
Al Viroe3fc6292012-05-30 20:08:42 -04001163unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 unsigned long len, unsigned long prot,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001165 unsigned long flags, unsigned long pgoff,
Michel Lespinasse41badc12013-02-22 16:32:47 -08001166 unsigned long *populate)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167{
1168 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 struct inode *inode;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001170 vm_flags_t vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171
Michel Lespinasse41badc12013-02-22 16:32:47 -08001172 *populate = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001173
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 /*
1175 * Does the application expect PROT_READ to imply PROT_EXEC?
1176 *
1177 * (the exception is when the underlying filesystem is noexec
1178 * mounted, in which case we dont add PROT_EXEC.)
1179 */
1180 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001181 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 prot |= PROT_EXEC;
1183
1184 if (!len)
1185 return -EINVAL;
1186
Eric Paris7cd94142007-11-26 18:47:40 -05001187 if (!(flags & MAP_FIXED))
1188 addr = round_hint_to_min(addr);
1189
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 /* Careful about overflows.. */
1191 len = PAGE_ALIGN(len);
Al Viro9206de92009-12-03 15:23:11 -05001192 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 return -ENOMEM;
1194
1195 /* offset overflow? */
1196 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
1197 return -EOVERFLOW;
1198
1199 /* Too many mappings? */
1200 if (mm->map_count > sysctl_max_map_count)
1201 return -ENOMEM;
1202
1203 /* Obtain the address to map to. we verify (or select) it and ensure
1204 * that it represents a valid section of the address space.
1205 */
1206 addr = get_unmapped_area(file, addr, len, pgoff, flags);
1207 if (addr & ~PAGE_MASK)
1208 return addr;
1209
1210 /* Do simple checking here so the lower-level routines won't have
1211 * to. we assume access permissions have been handled by the open
1212 * of the memory object, so we don't do any here.
1213 */
1214 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
1215 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1216
Huang Shijiecdf7b342009-09-21 17:03:36 -07001217 if (flags & MAP_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 if (!can_do_mlock())
1219 return -EPERM;
Rik van Rielba470de2008-10-18 20:26:50 -07001220
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 /* mlock MCL_FUTURE? */
1222 if (vm_flags & VM_LOCKED) {
1223 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001224 locked = len >> PAGE_SHIFT;
1225 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08001226 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07001227 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1229 return -EAGAIN;
1230 }
1231
Al Viro496ad9a2013-01-23 17:07:38 -05001232 inode = file ? file_inode(file) : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
1234 if (file) {
1235 switch (flags & MAP_TYPE) {
1236 case MAP_SHARED:
1237 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
1238 return -EACCES;
1239
1240 /*
1241 * Make sure we don't allow writing to an append-only
1242 * file..
1243 */
1244 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
1245 return -EACCES;
1246
1247 /*
1248 * Make sure there are no mandatory locks on the file.
1249 */
1250 if (locks_verify_locked(inode))
1251 return -EAGAIN;
1252
1253 vm_flags |= VM_SHARED | VM_MAYSHARE;
1254 if (!(file->f_mode & FMODE_WRITE))
1255 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
1256
1257 /* fall through */
1258 case MAP_PRIVATE:
1259 if (!(file->f_mode & FMODE_READ))
1260 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -08001261 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -07001262 if (vm_flags & VM_EXEC)
1263 return -EPERM;
1264 vm_flags &= ~VM_MAYEXEC;
1265 }
Linus Torvalds80c56062006-10-15 14:09:55 -07001266
1267 if (!file->f_op || !file->f_op->mmap)
1268 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 break;
1270
1271 default:
1272 return -EINVAL;
1273 }
1274 } else {
1275 switch (flags & MAP_TYPE) {
1276 case MAP_SHARED:
Tejun Heoce363942008-09-03 16:09:47 +02001277 /*
1278 * Ignore pgoff.
1279 */
1280 pgoff = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 vm_flags |= VM_SHARED | VM_MAYSHARE;
1282 break;
1283 case MAP_PRIVATE:
1284 /*
1285 * Set pgoff according to addr for anon_vma.
1286 */
1287 pgoff = addr >> PAGE_SHIFT;
1288 break;
1289 default:
1290 return -EINVAL;
1291 }
1292 }
1293
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001294 /*
1295 * Set 'VM_NORESERVE' if we should not account for the
1296 * memory use of this mapping.
1297 */
1298 if (flags & MAP_NORESERVE) {
1299 /* We honor MAP_NORESERVE if allowed to overcommit */
1300 if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
1301 vm_flags |= VM_NORESERVE;
1302
1303 /* hugetlb applies strict overcommit unless MAP_NORESERVE */
1304 if (file && is_file_hugepages(file))
1305 vm_flags |= VM_NORESERVE;
1306 }
1307
1308 addr = mmap_region(file, addr, len, vm_flags, pgoff);
Michel Lespinasse18693052013-02-22 16:32:46 -08001309 if (!IS_ERR_VALUE(addr) && (vm_flags & VM_POPULATE))
Michel Lespinasse41badc12013-02-22 16:32:47 -08001310 *populate = len;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001311 return addr;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001312}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001313
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001314SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1315 unsigned long, prot, unsigned long, flags,
1316 unsigned long, fd, unsigned long, pgoff)
1317{
1318 struct file *file = NULL;
1319 unsigned long retval = -EBADF;
1320
1321 if (!(flags & MAP_ANONYMOUS)) {
Al Viro120a7952010-10-30 02:54:44 -04001322 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001323 if (unlikely(flags & MAP_HUGETLB))
1324 return -EINVAL;
1325 file = fget(fd);
1326 if (!file)
1327 goto out;
1328 } else if (flags & MAP_HUGETLB) {
1329 struct user_struct *user = NULL;
1330 /*
1331 * VM_NORESERVE is used because the reservations will be
1332 * taken when vm_ops->mmap() is called
1333 * A dummy user value is used because we are not locking
1334 * memory so no accounting is necessary
1335 */
Steven Truelove40716e22012-03-21 16:34:14 -07001336 file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len,
Andi Kleen42d73952012-12-11 16:01:34 -08001337 VM_NORESERVE,
1338 &user, HUGETLB_ANONHUGE_INODE,
1339 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001340 if (IS_ERR(file))
1341 return PTR_ERR(file);
1342 }
1343
1344 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1345
Al Viroeb36c582012-05-30 20:17:35 -04001346 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001347 if (file)
1348 fput(file);
1349out:
1350 return retval;
1351}
1352
Christoph Hellwiga4679372010-03-10 15:21:15 -08001353#ifdef __ARCH_WANT_SYS_OLD_MMAP
1354struct mmap_arg_struct {
1355 unsigned long addr;
1356 unsigned long len;
1357 unsigned long prot;
1358 unsigned long flags;
1359 unsigned long fd;
1360 unsigned long offset;
1361};
1362
1363SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1364{
1365 struct mmap_arg_struct a;
1366
1367 if (copy_from_user(&a, arg, sizeof(a)))
1368 return -EFAULT;
1369 if (a.offset & ~PAGE_MASK)
1370 return -EINVAL;
1371
1372 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1373 a.offset >> PAGE_SHIFT);
1374}
1375#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1376
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001377/*
1378 * Some shared mappigns will want the pages marked read-only
1379 * to track write events. If so, we'll downgrade vm_page_prot
1380 * to the private version (using protection_map[] without the
1381 * VM_SHARED bit).
1382 */
1383int vma_wants_writenotify(struct vm_area_struct *vma)
1384{
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001385 vm_flags_t vm_flags = vma->vm_flags;
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001386
1387 /* If it was private or non-writable, the write bit is already clear */
1388 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1389 return 0;
1390
1391 /* The backer wishes to know when pages are first written to? */
1392 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1393 return 1;
1394
1395 /* The open routine did something to the protections already? */
1396 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001397 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001398 return 0;
1399
1400 /* Specialty mapping? */
Konstantin Khlebnikov4b6e1e32012-10-08 16:28:40 -07001401 if (vm_flags & VM_PFNMAP)
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001402 return 0;
1403
1404 /* Can the mapping track the dirty pages? */
1405 return vma->vm_file && vma->vm_file->f_mapping &&
1406 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1407}
1408
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001409/*
1410 * We account for memory if it's a private writeable mapping,
Mel Gorman5a6fe122009-02-10 14:02:27 +00001411 * not hugepages and VM_NORESERVE wasn't set.
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001412 */
KOSAKI Motohiroca16d142011-05-26 19:16:19 +09001413static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001414{
Mel Gorman5a6fe122009-02-10 14:02:27 +00001415 /*
1416 * hugetlb has its own accounting separate from the core VM
1417 * VM_HUGETLB may not be set yet so we cannot check for that flag.
1418 */
1419 if (file && is_file_hugepages(file))
1420 return 0;
1421
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001422 return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
1423}
1424
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001425unsigned long mmap_region(struct file *file, unsigned long addr,
Michel Lespinassec22c0d62013-02-22 16:32:43 -08001426 unsigned long len, vm_flags_t vm_flags, unsigned long pgoff)
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001427{
1428 struct mm_struct *mm = current->mm;
1429 struct vm_area_struct *vma, *prev;
1430 int correct_wcount = 0;
1431 int error;
1432 struct rb_node **rb_link, *rb_parent;
1433 unsigned long charged = 0;
Al Viro496ad9a2013-01-23 17:07:38 -05001434 struct inode *inode = file ? file_inode(file) : NULL;
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001435
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436 /* Clear old maps */
1437 error = -ENOMEM;
1438munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07001439 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 if (do_munmap(mm, addr, len))
1441 return -ENOMEM;
1442 goto munmap_back;
1443 }
1444
1445 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001446 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 return -ENOMEM;
1448
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001449 /*
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001450 * Private writable mapping: check memory availability
1451 */
Mel Gorman5a6fe122009-02-10 14:02:27 +00001452 if (accountable_mapping(file, vm_flags)) {
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001453 charged = len >> PAGE_SHIFT;
Al Viro191c5422012-02-13 03:58:52 +00001454 if (security_vm_enough_memory_mm(mm, charged))
Linus Torvaldsfc8744a2009-01-31 15:08:56 -08001455 return -ENOMEM;
1456 vm_flags |= VM_ACCOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 }
1458
1459 /*
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001460 * Can we just expand an old mapping?
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 */
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001462 vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
1463 if (vma)
1464 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465
1466 /*
1467 * Determine the object being mapped and call the appropriate
1468 * specific mapper. the address has already been validated, but
1469 * not unmapped, but the maps are removed from the list.
1470 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001471 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 if (!vma) {
1473 error = -ENOMEM;
1474 goto unacct_error;
1475 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476
1477 vma->vm_mm = mm;
1478 vma->vm_start = addr;
1479 vma->vm_end = addr + len;
1480 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001481 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 vma->vm_pgoff = pgoff;
Rik van Riel5beb4932010-03-05 13:42:07 -08001483 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484
Hugh Dickinsce8fea72012-03-06 12:28:52 -08001485 error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */
1486
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1489 goto free_vma;
1490 if (vm_flags & VM_DENYWRITE) {
1491 error = deny_write_access(file);
1492 if (error)
1493 goto free_vma;
1494 correct_wcount = 1;
1495 }
Al Virocb0942b2012-08-27 14:48:26 -04001496 vma->vm_file = get_file(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 error = file->f_op->mmap(file, vma);
1498 if (error)
1499 goto unmap_and_free_vma;
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001500
1501 /* Can addr have changed??
1502 *
1503 * Answer: Yes, several device drivers can do it in their
1504 * f_op->mmap method. -DaveM
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001505 * Bug: If addr is changed, prev, rb_link, rb_parent should
1506 * be updated for vma_link()
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001507 */
Joonsoo Kim2897b4d2012-12-12 13:51:53 -08001508 WARN_ON_ONCE(addr != vma->vm_start);
1509
Huang Shijief8dbf0a72009-09-21 17:03:41 -07001510 addr = vma->vm_start;
1511 pgoff = vma->vm_pgoff;
1512 vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513 } else if (vm_flags & VM_SHARED) {
Al Viro835ee792012-03-05 06:39:47 +00001514 if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP)))
1515 goto free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516 error = shmem_zero_setup(vma);
1517 if (error)
1518 goto free_vma;
1519 }
1520
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001521 if (vma_wants_writenotify(vma)) {
1522 pgprot_t pprot = vma->vm_page_prot;
1523
1524 /* Can vma->vm_page_prot have changed??
1525 *
1526 * Answer: Yes, drivers may have changed it in their
1527 * f_op->mmap method.
1528 *
1529 * Ensures that vmas marked as uncached stay that way.
1530 */
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001531 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Magnus Dammc9d0bf22009-12-14 17:59:49 -08001532 if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
1533 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1534 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001535
Linus Torvaldsde33c8d2009-01-29 17:46:42 -08001536 vma_link(mm, vma, prev, rb_link, rb_parent);
1537 file = vma->vm_file;
Oleg Nesterov4d3d5b42008-04-28 02:12:10 -07001538
1539 /* Once vma denies write, undo our temporary denial count */
1540 if (correct_wcount)
1541 atomic_inc(&inode->i_writecount);
1542out:
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001543 perf_event_mmap(vma);
Peter Zijlstra0a4a9392009-03-30 19:07:05 +02001544
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001545 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546 if (vm_flags & VM_LOCKED) {
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001547 if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) ||
1548 vma == get_gate_vma(current->mm)))
KOSAKI Motohiro06f9d8c2010-03-05 13:41:43 -08001549 mm->locked_vm += (len >> PAGE_SHIFT);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001550 else
1551 vma->vm_flags &= ~VM_LOCKED;
1552 }
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301553
Oleg Nesterovc7a3a882012-08-19 19:10:42 +02001554 if (file)
1555 uprobe_mmap(vma);
Srikar Dronamraju2b144492012-02-09 14:56:42 +05301556
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 return addr;
1558
1559unmap_and_free_vma:
1560 if (correct_wcount)
1561 atomic_inc(&inode->i_writecount);
1562 vma->vm_file = NULL;
1563 fput(file);
1564
1565 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001566 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1567 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568free_vma:
1569 kmem_cache_free(vm_area_cachep, vma);
1570unacct_error:
1571 if (charged)
1572 vm_unacct_memory(charged);
1573 return error;
1574}
1575
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001576unsigned long unmapped_area(struct vm_unmapped_area_info *info)
1577{
1578 /*
1579 * We implement the search by looking for an rbtree node that
1580 * immediately follows a suitable gap. That is,
1581 * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length;
1582 * - gap_end = vma->vm_start >= info->low_limit + length;
1583 * - gap_end - gap_start >= length
1584 */
1585
1586 struct mm_struct *mm = current->mm;
1587 struct vm_area_struct *vma;
1588 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1589
1590 /* Adjust search length to account for worst case alignment overhead */
1591 length = info->length + info->align_mask;
1592 if (length < info->length)
1593 return -ENOMEM;
1594
1595 /* Adjust search limits by the desired length */
1596 if (info->high_limit < length)
1597 return -ENOMEM;
1598 high_limit = info->high_limit - length;
1599
1600 if (info->low_limit > high_limit)
1601 return -ENOMEM;
1602 low_limit = info->low_limit + length;
1603
1604 /* Check if rbtree root looks promising */
1605 if (RB_EMPTY_ROOT(&mm->mm_rb))
1606 goto check_highest;
1607 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1608 if (vma->rb_subtree_gap < length)
1609 goto check_highest;
1610
1611 while (true) {
1612 /* Visit left subtree if it looks promising */
1613 gap_end = vma->vm_start;
1614 if (gap_end >= low_limit && vma->vm_rb.rb_left) {
1615 struct vm_area_struct *left =
1616 rb_entry(vma->vm_rb.rb_left,
1617 struct vm_area_struct, vm_rb);
1618 if (left->rb_subtree_gap >= length) {
1619 vma = left;
1620 continue;
1621 }
1622 }
1623
1624 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1625check_current:
1626 /* Check if current node has a suitable gap */
1627 if (gap_start > high_limit)
1628 return -ENOMEM;
1629 if (gap_end >= low_limit && gap_end - gap_start >= length)
1630 goto found;
1631
1632 /* Visit right subtree if it looks promising */
1633 if (vma->vm_rb.rb_right) {
1634 struct vm_area_struct *right =
1635 rb_entry(vma->vm_rb.rb_right,
1636 struct vm_area_struct, vm_rb);
1637 if (right->rb_subtree_gap >= length) {
1638 vma = right;
1639 continue;
1640 }
1641 }
1642
1643 /* Go back up the rbtree to find next candidate node */
1644 while (true) {
1645 struct rb_node *prev = &vma->vm_rb;
1646 if (!rb_parent(prev))
1647 goto check_highest;
1648 vma = rb_entry(rb_parent(prev),
1649 struct vm_area_struct, vm_rb);
1650 if (prev == vma->vm_rb.rb_left) {
1651 gap_start = vma->vm_prev->vm_end;
1652 gap_end = vma->vm_start;
1653 goto check_current;
1654 }
1655 }
1656 }
1657
1658check_highest:
1659 /* Check highest gap, which does not precede any rbtree node */
1660 gap_start = mm->highest_vm_end;
1661 gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */
1662 if (gap_start > high_limit)
1663 return -ENOMEM;
1664
1665found:
1666 /* We found a suitable gap. Clip it with the original low_limit. */
1667 if (gap_start < info->low_limit)
1668 gap_start = info->low_limit;
1669
1670 /* Adjust gap address to the desired alignment */
1671 gap_start += (info->align_offset - gap_start) & info->align_mask;
1672
1673 VM_BUG_ON(gap_start + info->length > info->high_limit);
1674 VM_BUG_ON(gap_start + info->length > gap_end);
1675 return gap_start;
1676}
1677
1678unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info)
1679{
1680 struct mm_struct *mm = current->mm;
1681 struct vm_area_struct *vma;
1682 unsigned long length, low_limit, high_limit, gap_start, gap_end;
1683
1684 /* Adjust search length to account for worst case alignment overhead */
1685 length = info->length + info->align_mask;
1686 if (length < info->length)
1687 return -ENOMEM;
1688
1689 /*
1690 * Adjust search limits by the desired length.
1691 * See implementation comment at top of unmapped_area().
1692 */
1693 gap_end = info->high_limit;
1694 if (gap_end < length)
1695 return -ENOMEM;
1696 high_limit = gap_end - length;
1697
1698 if (info->low_limit > high_limit)
1699 return -ENOMEM;
1700 low_limit = info->low_limit + length;
1701
1702 /* Check highest gap, which does not precede any rbtree node */
1703 gap_start = mm->highest_vm_end;
1704 if (gap_start <= high_limit)
1705 goto found_highest;
1706
1707 /* Check if rbtree root looks promising */
1708 if (RB_EMPTY_ROOT(&mm->mm_rb))
1709 return -ENOMEM;
1710 vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
1711 if (vma->rb_subtree_gap < length)
1712 return -ENOMEM;
1713
1714 while (true) {
1715 /* Visit right subtree if it looks promising */
1716 gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
1717 if (gap_start <= high_limit && vma->vm_rb.rb_right) {
1718 struct vm_area_struct *right =
1719 rb_entry(vma->vm_rb.rb_right,
1720 struct vm_area_struct, vm_rb);
1721 if (right->rb_subtree_gap >= length) {
1722 vma = right;
1723 continue;
1724 }
1725 }
1726
1727check_current:
1728 /* Check if current node has a suitable gap */
1729 gap_end = vma->vm_start;
1730 if (gap_end < low_limit)
1731 return -ENOMEM;
1732 if (gap_start <= high_limit && gap_end - gap_start >= length)
1733 goto found;
1734
1735 /* Visit left subtree if it looks promising */
1736 if (vma->vm_rb.rb_left) {
1737 struct vm_area_struct *left =
1738 rb_entry(vma->vm_rb.rb_left,
1739 struct vm_area_struct, vm_rb);
1740 if (left->rb_subtree_gap >= length) {
1741 vma = left;
1742 continue;
1743 }
1744 }
1745
1746 /* Go back up the rbtree to find next candidate node */
1747 while (true) {
1748 struct rb_node *prev = &vma->vm_rb;
1749 if (!rb_parent(prev))
1750 return -ENOMEM;
1751 vma = rb_entry(rb_parent(prev),
1752 struct vm_area_struct, vm_rb);
1753 if (prev == vma->vm_rb.rb_right) {
1754 gap_start = vma->vm_prev ?
1755 vma->vm_prev->vm_end : 0;
1756 goto check_current;
1757 }
1758 }
1759 }
1760
1761found:
1762 /* We found a suitable gap. Clip it with the original high_limit. */
1763 if (gap_end > info->high_limit)
1764 gap_end = info->high_limit;
1765
1766found_highest:
1767 /* Compute highest gap address at the desired alignment */
1768 gap_end -= info->length;
1769 gap_end -= (gap_end - info->align_offset) & info->align_mask;
1770
1771 VM_BUG_ON(gap_end < info->low_limit);
1772 VM_BUG_ON(gap_end < gap_start);
1773 return gap_end;
1774}
1775
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776/* Get an address range which is currently unmapped.
1777 * For shmat() with addr=0.
1778 *
1779 * Ugly calling convention alert:
1780 * Return value with the low bits set means error value,
1781 * ie
1782 * if (ret & ~PAGE_MASK)
1783 * error = ret;
1784 *
1785 * This function "knows" that -ENOMEM has the bits set.
1786 */
1787#ifndef HAVE_ARCH_UNMAPPED_AREA
1788unsigned long
1789arch_get_unmapped_area(struct file *filp, unsigned long addr,
1790 unsigned long len, unsigned long pgoff, unsigned long flags)
1791{
1792 struct mm_struct *mm = current->mm;
1793 struct vm_area_struct *vma;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001794 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795
1796 if (len > TASK_SIZE)
1797 return -ENOMEM;
1798
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001799 if (flags & MAP_FIXED)
1800 return addr;
1801
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 if (addr) {
1803 addr = PAGE_ALIGN(addr);
1804 vma = find_vma(mm, addr);
1805 if (TASK_SIZE - len >= addr &&
1806 (!vma || addr + len <= vma->vm_start))
1807 return addr;
1808 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001810 info.flags = 0;
1811 info.length = len;
1812 info.low_limit = TASK_UNMAPPED_BASE;
1813 info.high_limit = TASK_SIZE;
1814 info.align_mask = 0;
1815 return vm_unmapped_area(&info);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001816}
1817#endif
1818
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001819void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820{
1821 /*
1822 * Is this a new hole at the lowest possible address?
1823 */
Xiao Guangrongf44d2192012-03-21 16:33:56 -07001824 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache)
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001825 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826}
1827
1828/*
1829 * This mmap-allocator allocates new areas top-down from below the
1830 * stack's low limit (the base):
1831 */
1832#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1833unsigned long
1834arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1835 const unsigned long len, const unsigned long pgoff,
1836 const unsigned long flags)
1837{
1838 struct vm_area_struct *vma;
1839 struct mm_struct *mm = current->mm;
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001840 unsigned long addr = addr0;
1841 struct vm_unmapped_area_info info;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842
1843 /* requested length too big for entire address space */
1844 if (len > TASK_SIZE)
1845 return -ENOMEM;
1846
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001847 if (flags & MAP_FIXED)
1848 return addr;
1849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 /* requesting a specific address */
1851 if (addr) {
1852 addr = PAGE_ALIGN(addr);
1853 vma = find_vma(mm, addr);
1854 if (TASK_SIZE - len >= addr &&
1855 (!vma || addr + len <= vma->vm_start))
1856 return addr;
1857 }
1858
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001859 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
1860 info.length = len;
1861 info.low_limit = PAGE_SIZE;
1862 info.high_limit = mm->mmap_base;
1863 info.align_mask = 0;
1864 addr = vm_unmapped_area(&info);
Xiao Guangrongb716ad92012-03-21 16:33:56 -07001865
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 /*
1867 * A failed mmap() very likely causes application failure,
1868 * so fall back to the bottom-up function here. This scenario
1869 * can happen with large stack limits and large mmap()
1870 * allocations.
1871 */
Michel Lespinassedb4fbfb2012-12-11 16:01:49 -08001872 if (addr & ~PAGE_MASK) {
1873 VM_BUG_ON(addr != -ENOMEM);
1874 info.flags = 0;
1875 info.low_limit = TASK_UNMAPPED_BASE;
1876 info.high_limit = TASK_SIZE;
1877 addr = vm_unmapped_area(&info);
1878 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879
1880 return addr;
1881}
1882#endif
1883
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001884void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885{
1886 /*
1887 * Is this a new hole at the highest possible address?
1888 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001889 if (addr > mm->free_area_cache)
1890 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891
1892 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001893 if (mm->free_area_cache > mm->mmap_base)
1894 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895}
1896
1897unsigned long
1898get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1899 unsigned long pgoff, unsigned long flags)
1900{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001901 unsigned long (*get_area)(struct file *, unsigned long,
1902 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001903
Al Viro9206de92009-12-03 15:23:11 -05001904 unsigned long error = arch_mmap_check(addr, len, flags);
1905 if (error)
1906 return error;
1907
1908 /* Careful about overflows.. */
1909 if (len > TASK_SIZE)
1910 return -ENOMEM;
1911
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001912 get_area = current->mm->get_unmapped_area;
1913 if (file && file->f_op && file->f_op->get_unmapped_area)
1914 get_area = file->f_op->get_unmapped_area;
1915 addr = get_area(file, addr, len, pgoff, flags);
1916 if (IS_ERR_VALUE(addr))
1917 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001919 if (addr > TASK_SIZE - len)
1920 return -ENOMEM;
1921 if (addr & ~PAGE_MASK)
1922 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001923
Al Viro9ac4ed42012-05-30 17:13:15 -04001924 addr = arch_rebalance_pgtables(addr, len);
1925 error = security_mmap_addr(addr);
1926 return error ? error : addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927}
1928
1929EXPORT_SYMBOL(get_unmapped_area);
1930
1931/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
ZhenwenXu48aae422009-01-06 14:40:21 -08001932struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933{
1934 struct vm_area_struct *vma = NULL;
1935
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001936 if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */
1937 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001939 /* Check the cache first. */
1940 /* (Cache hit rate is typically around 35%.) */
1941 vma = mm->mmap_cache;
1942 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1943 struct rb_node *rb_node;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001945 rb_node = mm->mm_rb.rb_node;
1946 vma = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001948 while (rb_node) {
1949 struct vm_area_struct *vma_tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001951 vma_tmp = rb_entry(rb_node,
1952 struct vm_area_struct, vm_rb);
1953
1954 if (vma_tmp->vm_end > addr) {
1955 vma = vma_tmp;
1956 if (vma_tmp->vm_start <= addr)
1957 break;
1958 rb_node = rb_node->rb_left;
1959 } else
1960 rb_node = rb_node->rb_right;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961 }
Rajman Mekaco841e31e2012-05-29 15:06:21 -07001962 if (vma)
1963 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964 }
1965 return vma;
1966}
1967
1968EXPORT_SYMBOL(find_vma);
1969
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001970/*
1971 * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001972 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973struct vm_area_struct *
1974find_vma_prev(struct mm_struct *mm, unsigned long addr,
1975 struct vm_area_struct **pprev)
1976{
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001977 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001979 vma = find_vma(mm, addr);
Mikulas Patocka83cd9042012-03-04 19:52:03 -05001980 if (vma) {
1981 *pprev = vma->vm_prev;
1982 } else {
1983 struct rb_node *rb_node = mm->mm_rb.rb_node;
1984 *pprev = NULL;
1985 while (rb_node) {
1986 *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1987 rb_node = rb_node->rb_right;
1988 }
1989 }
KOSAKI Motohiro6bd48372012-01-10 15:08:07 -08001990 return vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991}
1992
1993/*
1994 * Verify that the stack growth is acceptable and
1995 * update accounting. This is shared with both the
1996 * grow-up and grow-down cases.
1997 */
ZhenwenXu48aae422009-01-06 14:40:21 -08001998static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001999{
2000 struct mm_struct *mm = vma->vm_mm;
2001 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08002002 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003
2004 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002005 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006 return -ENOMEM;
2007
2008 /* Stack limit test */
Jiri Slaby59e99e52010-03-05 13:41:44 -08002009 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010 return -ENOMEM;
2011
2012 /* mlock limit tests */
2013 if (vma->vm_flags & VM_LOCKED) {
2014 unsigned long locked;
2015 unsigned long limit;
2016 locked = mm->locked_vm + grow;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002017 limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
2018 limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019 if (locked > limit && !capable(CAP_IPC_LOCK))
2020 return -ENOMEM;
2021 }
2022
Adam Litke0d59a012007-01-30 14:35:39 -08002023 /* Check to ensure the stack will not grow into a hugetlb-only region */
2024 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
2025 vma->vm_end - size;
2026 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
2027 return -EFAULT;
2028
Linus Torvalds1da177e2005-04-16 15:20:36 -07002029 /*
2030 * Overcommit.. This must be the final test, as it will
2031 * update security statistics.
2032 */
Hugh Dickins05fa1992009-04-16 21:58:12 +01002033 if (security_vm_enough_memory_mm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034 return -ENOMEM;
2035
2036 /* Ok, everything looks good - let it rip */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 if (vma->vm_flags & VM_LOCKED)
2038 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07002039 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002040 return 0;
2041}
2042
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002043#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002045 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
2046 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 */
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002048int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049{
2050 int error;
2051
2052 if (!(vma->vm_flags & VM_GROWSUP))
2053 return -EFAULT;
2054
2055 /*
2056 * We must make sure the anon_vma is allocated
2057 * so that the anon_vma locking is not a noop.
2058 */
2059 if (unlikely(anon_vma_prepare(vma)))
2060 return -ENOMEM;
Rik van Rielbb4a3402010-08-09 17:18:37 -07002061 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062
2063 /*
2064 * vma->vm_start/vm_end cannot change under us because the caller
2065 * is required to hold the mmap_sem in read mode. We need the
2066 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01002067 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068 */
Helge Deller06b32f32006-12-19 19:28:33 +01002069 if (address < PAGE_ALIGN(address+4))
2070 address = PAGE_ALIGN(address+4);
2071 else {
Rik van Rielbb4a3402010-08-09 17:18:37 -07002072 vma_unlock_anon_vma(vma);
Helge Deller06b32f32006-12-19 19:28:33 +01002073 return -ENOMEM;
2074 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002075 error = 0;
2076
2077 /* Somebody else might have raced and expanded it already */
2078 if (address > vma->vm_end) {
2079 unsigned long size, grow;
2080
2081 size = address - vma->vm_start;
2082 grow = (address - vma->vm_end) >> PAGE_SHIFT;
2083
Hugh Dickins42c36f62011-05-09 17:44:42 -07002084 error = -ENOMEM;
2085 if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
2086 error = acct_stack_growth(vma, size, grow);
2087 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002088 /*
2089 * vma_gap_update() doesn't support concurrent
2090 * updates, but we only hold a shared mmap_sem
2091 * lock here, so we need to protect against
2092 * concurrent vma expansions.
2093 * vma_lock_anon_vma() doesn't help here, as
2094 * we don't guarantee that all growable vmas
2095 * in a mm share the same root anon vma.
2096 * So, we reuse mm->page_table_lock to guard
2097 * against concurrent vma expansions.
2098 */
2099 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002100 anon_vma_interval_tree_pre_update_vma(vma);
Hugh Dickins42c36f62011-05-09 17:44:42 -07002101 vma->vm_end = address;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002102 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002103 if (vma->vm_next)
2104 vma_gap_update(vma->vm_next);
2105 else
2106 vma->vm_mm->highest_vm_end = address;
Michel Lespinasse41289972012-12-12 13:52:25 -08002107 spin_unlock(&vma->vm_mm->page_table_lock);
2108
Hugh Dickins42c36f62011-05-09 17:44:42 -07002109 perf_event_mmap(vma);
2110 }
Eric B Munson3af9e852010-05-18 15:30:49 +01002111 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002113 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002114 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002115 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 return error;
2117}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07002118#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
2119
Linus Torvalds1da177e2005-04-16 15:20:36 -07002120/*
2121 * vma is the first one with address < vma->vm_start. Have to extend vma.
2122 */
Michal Hockod05f3162011-05-24 17:11:44 -07002123int expand_downwards(struct vm_area_struct *vma,
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002124 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125{
2126 int error;
2127
2128 /*
2129 * We must make sure the anon_vma is allocated
2130 * so that the anon_vma locking is not a noop.
2131 */
2132 if (unlikely(anon_vma_prepare(vma)))
2133 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05002134
2135 address &= PAGE_MASK;
Al Viroe5467852012-05-30 13:30:51 -04002136 error = security_mmap_addr(address);
Eric Paris88694772007-11-26 18:47:26 -05002137 if (error)
2138 return error;
2139
Rik van Rielbb4a3402010-08-09 17:18:37 -07002140 vma_lock_anon_vma(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002141
2142 /*
2143 * vma->vm_start/vm_end cannot change under us because the caller
2144 * is required to hold the mmap_sem in read mode. We need the
2145 * anon_vma lock to serialize against concurrent expand_stacks.
2146 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002147
2148 /* Somebody else might have raced and expanded it already */
2149 if (address < vma->vm_start) {
2150 unsigned long size, grow;
2151
2152 size = vma->vm_end - address;
2153 grow = (vma->vm_start - address) >> PAGE_SHIFT;
2154
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002155 error = -ENOMEM;
2156 if (grow <= vma->vm_pgoff) {
2157 error = acct_stack_growth(vma, size, grow);
2158 if (!error) {
Michel Lespinasse41289972012-12-12 13:52:25 -08002159 /*
2160 * vma_gap_update() doesn't support concurrent
2161 * updates, but we only hold a shared mmap_sem
2162 * lock here, so we need to protect against
2163 * concurrent vma expansions.
2164 * vma_lock_anon_vma() doesn't help here, as
2165 * we don't guarantee that all growable vmas
2166 * in a mm share the same root anon vma.
2167 * So, we reuse mm->page_table_lock to guard
2168 * against concurrent vma expansions.
2169 */
2170 spin_lock(&vma->vm_mm->page_table_lock);
Michel Lespinassebf181b92012-10-08 16:31:39 -07002171 anon_vma_interval_tree_pre_update_vma(vma);
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002172 vma->vm_start = address;
2173 vma->vm_pgoff -= grow;
Michel Lespinassebf181b92012-10-08 16:31:39 -07002174 anon_vma_interval_tree_post_update_vma(vma);
Michel Lespinassed3737182012-12-11 16:01:38 -08002175 vma_gap_update(vma);
Michel Lespinasse41289972012-12-12 13:52:25 -08002176 spin_unlock(&vma->vm_mm->page_table_lock);
2177
Linus Torvaldsa626ca62011-04-13 08:07:28 -07002178 perf_event_mmap(vma);
2179 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002180 }
2181 }
Rik van Rielbb4a3402010-08-09 17:18:37 -07002182 vma_unlock_anon_vma(vma);
Andrea Arcangelib15d00b2011-01-13 15:46:59 -08002183 khugepaged_enter_vma_merge(vma);
Michel Lespinasseed8ea812012-10-08 16:31:45 -07002184 validate_mm(vma->vm_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 return error;
2186}
2187
Linus Torvalds09884962013-02-27 08:36:04 -08002188/*
2189 * Note how expand_stack() refuses to expand the stack all the way to
2190 * abut the next virtual mapping, *unless* that mapping itself is also
2191 * a stack mapping. We want to leave room for a guard page, after all
2192 * (the guard page itself is not added here, that is done by the
2193 * actual page faulting logic)
2194 *
2195 * This matches the behavior of the guard page logic (see mm/memory.c:
2196 * check_stack_guard_page()), which only allows the guard page to be
2197 * removed under these circumstances.
2198 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002199#ifdef CONFIG_STACK_GROWSUP
2200int expand_stack(struct vm_area_struct *vma, unsigned long address)
2201{
Linus Torvalds09884962013-02-27 08:36:04 -08002202 struct vm_area_struct *next;
2203
2204 address &= PAGE_MASK;
2205 next = vma->vm_next;
2206 if (next && next->vm_start == address + PAGE_SIZE) {
2207 if (!(next->vm_flags & VM_GROWSUP))
2208 return -ENOMEM;
2209 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002210 return expand_upwards(vma, address);
2211}
2212
2213struct vm_area_struct *
2214find_extend_vma(struct mm_struct *mm, unsigned long addr)
2215{
2216 struct vm_area_struct *vma, *prev;
2217
2218 addr &= PAGE_MASK;
2219 vma = find_vma_prev(mm, addr, &prev);
2220 if (vma && (vma->vm_start <= addr))
2221 return vma;
Denys Vlasenko1c127182008-11-12 01:24:41 +01002222 if (!prev || expand_stack(prev, addr))
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002223 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002224 if (prev->vm_flags & VM_LOCKED)
2225 __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL);
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002226 return prev;
2227}
2228#else
2229int expand_stack(struct vm_area_struct *vma, unsigned long address)
2230{
Linus Torvalds09884962013-02-27 08:36:04 -08002231 struct vm_area_struct *prev;
2232
2233 address &= PAGE_MASK;
2234 prev = vma->vm_prev;
2235 if (prev && prev->vm_end == address) {
2236 if (!(prev->vm_flags & VM_GROWSDOWN))
2237 return -ENOMEM;
2238 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -07002239 return expand_downwards(vma, address);
2240}
2241
Linus Torvalds1da177e2005-04-16 15:20:36 -07002242struct vm_area_struct *
2243find_extend_vma(struct mm_struct * mm, unsigned long addr)
2244{
2245 struct vm_area_struct * vma;
2246 unsigned long start;
2247
2248 addr &= PAGE_MASK;
2249 vma = find_vma(mm,addr);
2250 if (!vma)
2251 return NULL;
2252 if (vma->vm_start <= addr)
2253 return vma;
2254 if (!(vma->vm_flags & VM_GROWSDOWN))
2255 return NULL;
2256 start = vma->vm_start;
2257 if (expand_stack(vma, addr))
2258 return NULL;
Michel Lespinassecea10a12013-02-22 16:32:44 -08002259 if (vma->vm_flags & VM_LOCKED)
2260 __mlock_vma_pages_range(vma, addr, start, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261 return vma;
2262}
2263#endif
2264
Linus Torvalds1da177e2005-04-16 15:20:36 -07002265/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002266 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002268 *
2269 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002271static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272{
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002273 unsigned long nr_accounted = 0;
2274
Hugh Dickins365e9c872005-10-29 18:16:18 -07002275 /* Update high watermark before we lower total_vm */
2276 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002278 long nrpages = vma_pages(vma);
2279
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002280 if (vma->vm_flags & VM_ACCOUNT)
2281 nr_accounted += nrpages;
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002282 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002283 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07002284 } while (vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002285 vm_unacct_memory(nr_accounted);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 validate_mm(mm);
2287}
2288
2289/*
2290 * Get rid of page table information in the indicated region.
2291 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07002292 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002293 */
2294static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07002295 struct vm_area_struct *vma, struct vm_area_struct *prev,
2296 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297{
Hugh Dickinse0da3822005-04-19 13:29:15 -07002298 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002299 struct mmu_gather tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300
2301 lru_add_drain();
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002302 tlb_gather_mmu(&tlb, mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002303 update_hiwater_rss(mm);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002304 unmap_vmas(&tlb, vma, start, end);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002305 free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
2306 next ? next->vm_start : 0);
2307 tlb_finish_mmu(&tlb, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002308}
2309
2310/*
2311 * Create a list of vma's touched by the unmap, removing them from the mm's
2312 * vma list as we go..
2313 */
2314static void
2315detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
2316 struct vm_area_struct *prev, unsigned long end)
2317{
2318 struct vm_area_struct **insertion_point;
2319 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07002320 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002321
2322 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002323 vma->vm_prev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324 do {
Michel Lespinassed3737182012-12-11 16:01:38 -08002325 vma_rb_erase(vma, &mm->mm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326 mm->map_count--;
2327 tail_vma = vma;
2328 vma = vma->vm_next;
2329 } while (vma && vma->vm_start < end);
2330 *insertion_point = vma;
Michel Lespinassed3737182012-12-11 16:01:38 -08002331 if (vma) {
Linus Torvalds297c5ee2010-08-20 16:24:55 -07002332 vma->vm_prev = prev;
Michel Lespinassed3737182012-12-11 16:01:38 -08002333 vma_gap_update(vma);
2334 } else
2335 mm->highest_vm_end = prev ? prev->vm_end : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07002337 if (mm->unmap_area == arch_unmap_area)
2338 addr = prev ? prev->vm_end : mm->mmap_base;
2339 else
2340 addr = vma ? vma->vm_start : mm->mmap_base;
2341 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002342 mm->mmap_cache = NULL; /* Kill the cache. */
2343}
2344
2345/*
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002346 * __split_vma() bypasses sysctl_max_map_count checking. We use this on the
2347 * munmap path where it doesn't make sense to fail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348 */
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002349static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350 unsigned long addr, int new_below)
2351{
2352 struct mempolicy *pol;
2353 struct vm_area_struct *new;
Rik van Riel5beb4932010-03-05 13:42:07 -08002354 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002355
Andi Kleena5516432008-07-23 21:27:41 -07002356 if (is_vm_hugetlb_page(vma) && (addr &
2357 ~(huge_page_mask(hstate_vma(vma)))))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358 return -EINVAL;
2359
Christoph Lametere94b1762006-12-06 20:33:17 -08002360 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 if (!new)
Rik van Riel5beb4932010-03-05 13:42:07 -08002362 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363
2364 /* most fields are the same, copy all, and then fixup */
2365 *new = *vma;
2366
Rik van Riel5beb4932010-03-05 13:42:07 -08002367 INIT_LIST_HEAD(&new->anon_vma_chain);
2368
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 if (new_below)
2370 new->vm_end = addr;
2371 else {
2372 new->vm_start = addr;
2373 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
2374 }
2375
Lee Schermerhorn846a16b2008-04-28 02:13:09 -07002376 pol = mpol_dup(vma_policy(vma));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377 if (IS_ERR(pol)) {
Rik van Riel5beb4932010-03-05 13:42:07 -08002378 err = PTR_ERR(pol);
2379 goto out_free_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 }
2381 vma_set_policy(new, pol);
2382
Rik van Riel5beb4932010-03-05 13:42:07 -08002383 if (anon_vma_clone(new, vma))
2384 goto out_free_mpol;
2385
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002386 if (new->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002387 get_file(new->vm_file);
2388
2389 if (new->vm_ops && new->vm_ops->open)
2390 new->vm_ops->open(new);
2391
2392 if (new_below)
Rik van Riel5beb4932010-03-05 13:42:07 -08002393 err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
Linus Torvalds1da177e2005-04-16 15:20:36 -07002394 ((addr - new->vm_start) >> PAGE_SHIFT), new);
2395 else
Rik van Riel5beb4932010-03-05 13:42:07 -08002396 err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397
Rik van Riel5beb4932010-03-05 13:42:07 -08002398 /* Success. */
2399 if (!err)
2400 return 0;
2401
2402 /* Clean everything up if vma_adjust failed. */
Rik van Riel58927532010-04-26 12:33:03 -04002403 if (new->vm_ops && new->vm_ops->close)
2404 new->vm_ops->close(new);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002405 if (new->vm_file)
Rik van Riel5beb4932010-03-05 13:42:07 -08002406 fput(new->vm_file);
Andrea Arcangeli2aeadc32010-09-22 13:05:12 -07002407 unlink_anon_vmas(new);
Rik van Riel5beb4932010-03-05 13:42:07 -08002408 out_free_mpol:
2409 mpol_put(pol);
2410 out_free_vma:
2411 kmem_cache_free(vm_area_cachep, new);
2412 out_err:
2413 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414}
2415
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002416/*
2417 * Split a vma into two pieces at address 'addr', a new vma is allocated
2418 * either for the first part or the tail.
2419 */
2420int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
2421 unsigned long addr, int new_below)
2422{
2423 if (mm->map_count >= sysctl_max_map_count)
2424 return -ENOMEM;
2425
2426 return __split_vma(mm, vma, addr, new_below);
2427}
2428
Linus Torvalds1da177e2005-04-16 15:20:36 -07002429/* Munmap is split into 2 main parts -- this part which finds
2430 * what needs doing, and the areas themselves, which do the
2431 * work. This now handles partial unmappings.
2432 * Jeremy Fitzhardinge <jeremy@goop.org>
2433 */
2434int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
2435{
2436 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07002437 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002438
2439 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
2440 return -EINVAL;
2441
2442 if ((len = PAGE_ALIGN(len)) == 0)
2443 return -EINVAL;
2444
2445 /* Find the first overlapping VMA */
Linus Torvalds9be34c92011-06-16 00:35:09 -07002446 vma = find_vma(mm, start);
Hugh Dickins146425a2005-04-19 13:29:18 -07002447 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002448 return 0;
Linus Torvalds9be34c92011-06-16 00:35:09 -07002449 prev = vma->vm_prev;
Hugh Dickins146425a2005-04-19 13:29:18 -07002450 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451
2452 /* if it doesn't overlap, we have nothing.. */
2453 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07002454 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002455 return 0;
2456
2457 /*
2458 * If we need to split any vma, do it now to save pain later.
2459 *
2460 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
2461 * unmapped vm_area_struct will remain in use: so lower split_vma
2462 * places tmp vma above, and higher split_vma places tmp vma below.
2463 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002464 if (start > vma->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002465 int error;
2466
2467 /*
2468 * Make sure that map_count on return from munmap() will
2469 * not exceed its limit; but let map_count go just above
2470 * its limit temporarily, to help free resources as expected.
2471 */
2472 if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count)
2473 return -ENOMEM;
2474
2475 error = __split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002476 if (error)
2477 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07002478 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002479 }
2480
2481 /* Does it split the last one? */
2482 last = find_vma(mm, end);
2483 if (last && end > last->vm_start) {
KOSAKI Motohiro659ace52009-12-14 17:57:56 -08002484 int error = __split_vma(mm, last, end, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485 if (error)
2486 return error;
2487 }
Hugh Dickins146425a2005-04-19 13:29:18 -07002488 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002489
2490 /*
Rik van Rielba470de2008-10-18 20:26:50 -07002491 * unlock any mlock()ed ranges before detaching vmas
2492 */
2493 if (mm->locked_vm) {
2494 struct vm_area_struct *tmp = vma;
2495 while (tmp && tmp->vm_start < end) {
2496 if (tmp->vm_flags & VM_LOCKED) {
2497 mm->locked_vm -= vma_pages(tmp);
2498 munlock_vma_pages_all(tmp);
2499 }
2500 tmp = tmp->vm_next;
2501 }
2502 }
2503
2504 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505 * Remove the vma's, and unmap the actual pages
2506 */
Hugh Dickins146425a2005-04-19 13:29:18 -07002507 detach_vmas_to_be_unmapped(mm, vma, prev, end);
2508 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509
2510 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07002511 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002512
2513 return 0;
2514}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002515
Al Virobfce2812012-04-20 21:57:04 -04002516int vm_munmap(unsigned long start, size_t len)
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002517{
2518 int ret;
Al Virobfce2812012-04-20 21:57:04 -04002519 struct mm_struct *mm = current->mm;
Linus Torvaldsa46ef992012-04-20 16:20:01 -07002520
2521 down_write(&mm->mmap_sem);
2522 ret = do_munmap(mm, start, len);
2523 up_write(&mm->mmap_sem);
2524 return ret;
2525}
2526EXPORT_SYMBOL(vm_munmap);
2527
Heiko Carstens6a6160a2009-01-14 14:14:15 +01002528SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530 profile_munmap(addr);
Al Virobfce2812012-04-20 21:57:04 -04002531 return vm_munmap(addr, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002532}
2533
2534static inline void verify_mm_writelocked(struct mm_struct *mm)
2535{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08002536#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
2538 WARN_ON(1);
2539 up_read(&mm->mmap_sem);
2540 }
2541#endif
2542}
2543
2544/*
2545 * this is really a simplified "do_mmap". it only handles
2546 * anonymous maps. eventually we may be able to do some
2547 * brk-specific accounting here.
2548 */
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002549static unsigned long do_brk(unsigned long addr, unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002550{
2551 struct mm_struct * mm = current->mm;
2552 struct vm_area_struct * vma, * prev;
2553 unsigned long flags;
2554 struct rb_node ** rb_link, * rb_parent;
2555 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04002556 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002557
2558 len = PAGE_ALIGN(len);
2559 if (!len)
2560 return addr;
2561
Kirill Korotaev3a459752006-09-07 14:17:04 +04002562 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
2563
Al Viro2c6a1012009-12-03 19:40:46 -05002564 error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
2565 if (error & ~PAGE_MASK)
Kirill Korotaev3a459752006-09-07 14:17:04 +04002566 return error;
2567
Linus Torvalds1da177e2005-04-16 15:20:36 -07002568 /*
2569 * mlock MCL_FUTURE?
2570 */
2571 if (mm->def_flags & VM_LOCKED) {
2572 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07002573 locked = len >> PAGE_SHIFT;
2574 locked += mm->locked_vm;
Jiri Slaby59e99e52010-03-05 13:41:44 -08002575 lock_limit = rlimit(RLIMIT_MEMLOCK);
Chris Wright93ea1d02005-05-01 08:58:38 -07002576 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
2578 return -EAGAIN;
2579 }
2580
2581 /*
2582 * mm->mmap_sem is required to protect against another thread
2583 * changing the mappings in case we sleep.
2584 */
2585 verify_mm_writelocked(mm);
2586
2587 /*
2588 * Clear old maps. this also does some error checking for us
2589 */
2590 munmap_back:
Hugh Dickins6597d782012-10-08 16:29:07 -07002591 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002592 if (do_munmap(mm, addr, len))
2593 return -ENOMEM;
2594 goto munmap_back;
2595 }
2596
2597 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07002598 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002599 return -ENOMEM;
2600
2601 if (mm->map_count > sysctl_max_map_count)
2602 return -ENOMEM;
2603
Al Viro191c5422012-02-13 03:58:52 +00002604 if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002605 return -ENOMEM;
2606
Linus Torvalds1da177e2005-04-16 15:20:36 -07002607 /* Can we just expand an old private anonymous mapping? */
Rik van Rielba470de2008-10-18 20:26:50 -07002608 vma = vma_merge(mm, prev, addr, addr + len, flags,
2609 NULL, NULL, pgoff, NULL);
2610 if (vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611 goto out;
2612
2613 /*
2614 * create a vma struct for an anonymous mapping
2615 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002616 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002617 if (!vma) {
2618 vm_unacct_memory(len >> PAGE_SHIFT);
2619 return -ENOMEM;
2620 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002621
Rik van Riel5beb4932010-03-05 13:42:07 -08002622 INIT_LIST_HEAD(&vma->anon_vma_chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002623 vma->vm_mm = mm;
2624 vma->vm_start = addr;
2625 vma->vm_end = addr + len;
2626 vma->vm_pgoff = pgoff;
2627 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002628 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002629 vma_link(mm, vma, prev, rb_link, rb_parent);
2630out:
Eric B Munson3af9e852010-05-18 15:30:49 +01002631 perf_event_mmap(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002632 mm->total_vm += len >> PAGE_SHIFT;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002633 if (flags & VM_LOCKED)
2634 mm->locked_vm += (len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002635 return addr;
2636}
2637
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002638unsigned long vm_brk(unsigned long addr, unsigned long len)
2639{
2640 struct mm_struct *mm = current->mm;
2641 unsigned long ret;
Michel Lespinasse128557f2013-02-22 16:32:40 -08002642 bool populate;
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002643
2644 down_write(&mm->mmap_sem);
2645 ret = do_brk(addr, len);
Michel Lespinasse128557f2013-02-22 16:32:40 -08002646 populate = ((mm->def_flags & VM_LOCKED) != 0);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002647 up_write(&mm->mmap_sem);
Michel Lespinasse128557f2013-02-22 16:32:40 -08002648 if (populate)
2649 mm_populate(addr, len);
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07002650 return ret;
2651}
2652EXPORT_SYMBOL(vm_brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002653
2654/* Release all mmaps. */
2655void exit_mmap(struct mm_struct *mm)
2656{
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002657 struct mmu_gather tlb;
Rik van Rielba470de2008-10-18 20:26:50 -07002658 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659 unsigned long nr_accounted = 0;
2660
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002661 /* mm's last user has gone, and its about to be pulled down */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002662 mmu_notifier_release(mm);
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002663
Rik van Rielba470de2008-10-18 20:26:50 -07002664 if (mm->locked_vm) {
2665 vma = mm->mmap;
2666 while (vma) {
2667 if (vma->vm_flags & VM_LOCKED)
2668 munlock_vma_pages_all(vma);
2669 vma = vma->vm_next;
2670 }
2671 }
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002672
2673 arch_exit_mmap(mm);
2674
Rik van Rielba470de2008-10-18 20:26:50 -07002675 vma = mm->mmap;
Jeremy Fitzhardinge9480c532009-02-11 13:04:41 -08002676 if (!vma) /* Can happen if dup_mmap() received an OOM */
2677 return;
2678
Linus Torvalds1da177e2005-04-16 15:20:36 -07002679 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680 flush_cache_mm(mm);
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002681 tlb_gather_mmu(&tlb, mm, 1);
Oleg Nesterov901608d2009-01-06 14:40:29 -08002682 /* update_hiwater_rss(mm) here? but nobody should be looking */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002683 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002684 unmap_vmas(&tlb, vma, 0, -1);
Hugh Dickins9ba69292009-09-21 17:02:20 -07002685
Peter Zijlstrad16dfc52011-05-24 17:11:45 -07002686 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Al Viro853f5e22012-03-05 14:03:47 -05002687 tlb_finish_mmu(&tlb, 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002688
Linus Torvalds1da177e2005-04-16 15:20:36 -07002689 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002690 * Walk the list again, actually closing and freeing it,
2691 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 */
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002693 while (vma) {
2694 if (vma->vm_flags & VM_ACCOUNT)
2695 nr_accounted += vma_pages(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002696 vma = remove_vma(vma);
Linus Torvalds4f74d2c2012-05-06 13:54:06 -07002697 }
2698 vm_unacct_memory(nr_accounted);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002699
Hugh Dickinsf9aed622012-08-21 16:15:45 -07002700 WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002701}
2702
2703/* Insert vm structure into process list sorted by address
2704 * and into the inode's i_mmap tree. If vm_file is non-NULL
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002705 * then i_mmap_mutex is taken here.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002706 */
Hugh Dickins6597d782012-10-08 16:29:07 -07002707int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002708{
Hugh Dickins6597d782012-10-08 16:29:07 -07002709 struct vm_area_struct *prev;
2710 struct rb_node **rb_link, *rb_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002711
2712 /*
2713 * The vm_pgoff of a purely anonymous vma should be irrelevant
2714 * until its first write fault, when page's anon_vma and index
2715 * are set. But now set the vm_pgoff it will almost certainly
2716 * end up with (unless mremap moves it elsewhere before that
2717 * first wfault), so /proc/pid/maps tells a consistent story.
2718 *
2719 * By setting it to reflect the virtual start address of the
2720 * vma, merges and splits can happen in a seamless way, just
2721 * using the existing file pgoff checks and manipulations.
2722 * Similarly in do_mmap_pgoff and in do_brk.
2723 */
2724 if (!vma->vm_file) {
2725 BUG_ON(vma->anon_vma);
2726 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2727 }
Hugh Dickins6597d782012-10-08 16:29:07 -07002728 if (find_vma_links(mm, vma->vm_start, vma->vm_end,
2729 &prev, &rb_link, &rb_parent))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002730 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002731 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002732 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002733 return -ENOMEM;
Srikar Dronamraju2b144492012-02-09 14:56:42 +05302734
Linus Torvalds1da177e2005-04-16 15:20:36 -07002735 vma_link(mm, vma, prev, rb_link, rb_parent);
2736 return 0;
2737}
2738
2739/*
2740 * Copy the vma structure to a new location in the same mm,
2741 * prior to moving page table entries, to effect an mremap move.
2742 */
2743struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
Michel Lespinasse38a76012012-10-08 16:31:50 -07002744 unsigned long addr, unsigned long len, pgoff_t pgoff,
2745 bool *need_rmap_locks)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002746{
2747 struct vm_area_struct *vma = *vmap;
2748 unsigned long vma_start = vma->vm_start;
2749 struct mm_struct *mm = vma->vm_mm;
2750 struct vm_area_struct *new_vma, *prev;
2751 struct rb_node **rb_link, *rb_parent;
2752 struct mempolicy *pol;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002753 bool faulted_in_anon_vma = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002754
2755 /*
2756 * If anonymous vma has not yet been faulted, update new pgoff
2757 * to match new location, to increase its chance of merging.
2758 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002759 if (unlikely(!vma->vm_file && !vma->anon_vma)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002760 pgoff = addr >> PAGE_SHIFT;
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002761 faulted_in_anon_vma = false;
2762 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002763
Hugh Dickins6597d782012-10-08 16:29:07 -07002764 if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
2765 return NULL; /* should never get here */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002766 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2767 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2768 if (new_vma) {
2769 /*
2770 * Source vma may have been merged into new_vma
2771 */
Andrea Arcangeli948f0172012-01-10 15:08:05 -08002772 if (unlikely(vma_start >= new_vma->vm_start &&
2773 vma_start < new_vma->vm_end)) {
2774 /*
2775 * The only way we can get a vma_merge with
2776 * self during an mremap is if the vma hasn't
2777 * been faulted in yet and we were allowed to
2778 * reset the dst vma->vm_pgoff to the
2779 * destination address of the mremap to allow
2780 * the merge to happen. mremap must change the
2781 * vm_pgoff linearity between src and dst vmas
2782 * (in turn preventing a vma_merge) to be
2783 * safe. It is only safe to keep the vm_pgoff
2784 * linear if there are no pages mapped yet.
2785 */
2786 VM_BUG_ON(faulted_in_anon_vma);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002787 *vmap = vma = new_vma;
Michel Lespinasse108d6642012-10-08 16:31:36 -07002788 }
Michel Lespinasse38a76012012-10-08 16:31:50 -07002789 *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002791 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002792 if (new_vma) {
2793 *new_vma = *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002794 new_vma->vm_start = addr;
2795 new_vma->vm_end = addr + len;
2796 new_vma->vm_pgoff = pgoff;
Michel Lespinasse523d4e22012-10-08 16:31:48 -07002797 pol = mpol_dup(vma_policy(vma));
2798 if (IS_ERR(pol))
2799 goto out_free_vma;
2800 vma_set_policy(new_vma, pol);
2801 INIT_LIST_HEAD(&new_vma->anon_vma_chain);
2802 if (anon_vma_clone(new_vma, vma))
2803 goto out_free_mempol;
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -07002804 if (new_vma->vm_file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002805 get_file(new_vma->vm_file);
2806 if (new_vma->vm_ops && new_vma->vm_ops->open)
2807 new_vma->vm_ops->open(new_vma);
2808 vma_link(mm, new_vma, prev, rb_link, rb_parent);
Michel Lespinasse38a76012012-10-08 16:31:50 -07002809 *need_rmap_locks = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002810 }
2811 }
2812 return new_vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08002813
2814 out_free_mempol:
2815 mpol_put(pol);
2816 out_free_vma:
2817 kmem_cache_free(vm_area_cachep, new_vma);
2818 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002819}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002820
2821/*
2822 * Return true if the calling process may expand its vm space by the passed
2823 * number of pages
2824 */
2825int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2826{
2827 unsigned long cur = mm->total_vm; /* pages */
2828 unsigned long lim;
2829
Jiri Slaby59e99e52010-03-05 13:41:44 -08002830 lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
akpm@osdl.org119f6572005-05-01 08:58:35 -07002831
2832 if (cur + npages > lim)
2833 return 0;
2834 return 1;
2835}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002836
2837
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002838static int special_mapping_fault(struct vm_area_struct *vma,
2839 struct vm_fault *vmf)
Roland McGrathfa5dc222007-02-08 14:20:41 -08002840{
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002841 pgoff_t pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002842 struct page **pages;
2843
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002844 /*
2845 * special mappings have no vm_file, and in that case, the mm
2846 * uses vm_pgoff internally. So we have to subtract it from here.
2847 * We are allowed to do this because we are the mm; do not copy
2848 * this code into drivers!
2849 */
2850 pgoff = vmf->pgoff - vma->vm_pgoff;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002851
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002852 for (pages = vma->vm_private_data; pgoff && *pages; ++pages)
2853 pgoff--;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002854
2855 if (*pages) {
2856 struct page *page = *pages;
2857 get_page(page);
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002858 vmf->page = page;
2859 return 0;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002860 }
2861
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002862 return VM_FAULT_SIGBUS;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002863}
2864
2865/*
2866 * Having a close hook prevents vma merging regardless of flags.
2867 */
2868static void special_mapping_close(struct vm_area_struct *vma)
2869{
2870}
2871
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04002872static const struct vm_operations_struct special_mapping_vmops = {
Roland McGrathfa5dc222007-02-08 14:20:41 -08002873 .close = special_mapping_close,
Nick Pigginb1d0e4f2008-02-09 01:15:19 +01002874 .fault = special_mapping_fault,
Roland McGrathfa5dc222007-02-08 14:20:41 -08002875};
2876
2877/*
2878 * Called with mm->mmap_sem held for writing.
2879 * Insert a new vma covering the given region, with the given flags.
2880 * Its pages are supplied by the given array of struct page *.
2881 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2882 * The region past the last page supplied will always produce SIGBUS.
2883 * The array pointer and the pages it points to are assumed to stay alive
2884 * for as long as this mapping might exist.
2885 */
2886int install_special_mapping(struct mm_struct *mm,
2887 unsigned long addr, unsigned long len,
2888 unsigned long vm_flags, struct page **pages)
2889{
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002890 int ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002891 struct vm_area_struct *vma;
2892
2893 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2894 if (unlikely(vma == NULL))
2895 return -ENOMEM;
2896
Rik van Riel5beb4932010-03-05 13:42:07 -08002897 INIT_LIST_HEAD(&vma->anon_vma_chain);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002898 vma->vm_mm = mm;
2899 vma->vm_start = addr;
2900 vma->vm_end = addr + len;
2901
Nick Piggin2f987352008-02-02 03:08:53 +01002902 vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND;
Coly Li3ed75eb2007-10-18 23:39:15 -07002903 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002904
2905 vma->vm_ops = &special_mapping_vmops;
2906 vma->vm_private_data = pages;
2907
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002908 ret = insert_vm_struct(mm, vma);
2909 if (ret)
2910 goto out;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002911
2912 mm->total_vm += len >> PAGE_SHIFT;
2913
Ingo Molnarcdd6c482009-09-21 12:02:48 +02002914 perf_event_mmap(vma);
Peter Zijlstra089dd792009-06-05 14:04:55 +02002915
Roland McGrathfa5dc222007-02-08 14:20:41 -08002916 return 0;
Tavis Ormandy462e635e2010-12-09 15:29:42 +01002917
2918out:
2919 kmem_cache_free(vm_area_cachep, vma);
2920 return ret;
Roland McGrathfa5dc222007-02-08 14:20:41 -08002921}
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002922
2923static DEFINE_MUTEX(mm_all_locks_mutex);
2924
Peter Zijlstra454ed842008-08-11 09:30:25 +02002925static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002926{
Michel Lespinassebf181b92012-10-08 16:31:39 -07002927 if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002928 /*
2929 * The LSB of head.next can't change from under us
2930 * because we hold the mm_all_locks_mutex.
2931 */
Jiri Kosina572043c2013-01-11 14:31:59 -08002932 down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002933 /*
2934 * We can safely modify head.next after taking the
Ingo Molnar5a505082012-12-02 19:56:46 +00002935 * anon_vma->root->rwsem. If some other vma in this mm shares
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002936 * the same anon_vma we won't take it again.
2937 *
2938 * No need of atomic instructions here, head.next
2939 * can't change from under us thanks to the
Ingo Molnar5a505082012-12-02 19:56:46 +00002940 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002941 */
2942 if (__test_and_set_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07002943 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002944 BUG();
2945 }
2946}
2947
Peter Zijlstra454ed842008-08-11 09:30:25 +02002948static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002949{
2950 if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
2951 /*
2952 * AS_MM_ALL_LOCKS can't change from under us because
2953 * we hold the mm_all_locks_mutex.
2954 *
2955 * Operations on ->flags have to be atomic because
2956 * even if AS_MM_ALL_LOCKS is stable thanks to the
2957 * mm_all_locks_mutex, there may be other cpus
2958 * changing other bitflags in parallel to us.
2959 */
2960 if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
2961 BUG();
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07002962 mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002963 }
2964}
2965
2966/*
2967 * This operation locks against the VM for all pte/vma/mm related
2968 * operations that could ever happen on a certain mm. This includes
2969 * vmtruncate, try_to_unmap, and all page faults.
2970 *
2971 * The caller must take the mmap_sem in write mode before calling
2972 * mm_take_all_locks(). The caller isn't allowed to release the
2973 * mmap_sem until mm_drop_all_locks() returns.
2974 *
2975 * mmap_sem in write mode is required in order to block all operations
2976 * that could modify pagetables and free pages without need of
2977 * altering the vma layout (for example populate_range() with
2978 * nonlinear vmas). It's also needed in write mode to avoid new
2979 * anon_vmas to be associated with existing vmas.
2980 *
2981 * A single task can't take more than one mm_take_all_locks() in a row
2982 * or it would deadlock.
2983 *
Michel Lespinassebf181b92012-10-08 16:31:39 -07002984 * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002985 * mapping->flags avoid to take the same lock twice, if more than one
2986 * vma in this mm is backed by the same anon_vma or address_space.
2987 *
2988 * We can take all the locks in random order because the VM code
Yuanhan Liu631b0cf2013-02-04 14:28:48 -08002989 * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never
Andrea Arcangeli7906d002008-07-28 15:46:26 -07002990 * takes more than one of them in a row. Secondly we're protected
2991 * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex.
2992 *
2993 * mm_take_all_locks() and mm_drop_all_locks are expensive operations
2994 * that may have to take thousand of locks.
2995 *
2996 * mm_take_all_locks() can fail if it's interrupted by signals.
2997 */
2998int mm_take_all_locks(struct mm_struct *mm)
2999{
3000 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003001 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003002
3003 BUG_ON(down_read_trylock(&mm->mmap_sem));
3004
3005 mutex_lock(&mm_all_locks_mutex);
3006
3007 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3008 if (signal_pending(current))
3009 goto out_unlock;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003010 if (vma->vm_file && vma->vm_file->f_mapping)
Peter Zijlstra454ed842008-08-11 09:30:25 +02003011 vm_lock_mapping(mm, vma->vm_file->f_mapping);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003012 }
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003013
3014 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3015 if (signal_pending(current))
3016 goto out_unlock;
3017 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003018 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3019 vm_lock_anon_vma(mm, avc->anon_vma);
Peter Zijlstra7cd5a022008-08-11 09:30:25 +02003020 }
3021
Kautuk Consul584cff52011-10-31 17:08:59 -07003022 return 0;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003023
3024out_unlock:
Kautuk Consul584cff52011-10-31 17:08:59 -07003025 mm_drop_all_locks(mm);
3026 return -EINTR;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003027}
3028
3029static void vm_unlock_anon_vma(struct anon_vma *anon_vma)
3030{
Michel Lespinassebf181b92012-10-08 16:31:39 -07003031 if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) {
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003032 /*
3033 * The LSB of head.next can't change to 0 from under
3034 * us because we hold the mm_all_locks_mutex.
3035 *
3036 * We must however clear the bitflag before unlocking
Michel Lespinassebf181b92012-10-08 16:31:39 -07003037 * the vma so the users using the anon_vma->rb_root will
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003038 * never see our bitflag.
3039 *
3040 * No need of atomic instructions here, head.next
3041 * can't change from under us until we release the
Ingo Molnar5a505082012-12-02 19:56:46 +00003042 * anon_vma->root->rwsem.
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003043 */
3044 if (!__test_and_clear_bit(0, (unsigned long *)
Michel Lespinassebf181b92012-10-08 16:31:39 -07003045 &anon_vma->root->rb_root.rb_node))
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003046 BUG();
Konstantin Khlebnikov08b52702013-02-22 16:34:40 -08003047 anon_vma_unlock_write(anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003048 }
3049}
3050
3051static void vm_unlock_mapping(struct address_space *mapping)
3052{
3053 if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
3054 /*
3055 * AS_MM_ALL_LOCKS can't change to 0 from under us
3056 * because we hold the mm_all_locks_mutex.
3057 */
Peter Zijlstra3d48ae42011-05-24 17:12:06 -07003058 mutex_unlock(&mapping->i_mmap_mutex);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003059 if (!test_and_clear_bit(AS_MM_ALL_LOCKS,
3060 &mapping->flags))
3061 BUG();
3062 }
3063}
3064
3065/*
3066 * The mmap_sem cannot be released by the caller until
3067 * mm_drop_all_locks() returns.
3068 */
3069void mm_drop_all_locks(struct mm_struct *mm)
3070{
3071 struct vm_area_struct *vma;
Rik van Riel5beb4932010-03-05 13:42:07 -08003072 struct anon_vma_chain *avc;
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003073
3074 BUG_ON(down_read_trylock(&mm->mmap_sem));
3075 BUG_ON(!mutex_is_locked(&mm_all_locks_mutex));
3076
3077 for (vma = mm->mmap; vma; vma = vma->vm_next) {
3078 if (vma->anon_vma)
Rik van Riel5beb4932010-03-05 13:42:07 -08003079 list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
3080 vm_unlock_anon_vma(avc->anon_vma);
Andrea Arcangeli7906d002008-07-28 15:46:26 -07003081 if (vma->vm_file && vma->vm_file->f_mapping)
3082 vm_unlock_mapping(vma->vm_file->f_mapping);
3083 }
3084
3085 mutex_unlock(&mm_all_locks_mutex);
3086}
David Howells8feae132009-01-08 12:04:47 +00003087
3088/*
3089 * initialise the VMA slab
3090 */
3091void __init mmap_init(void)
3092{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07003093 int ret;
3094
3095 ret = percpu_counter_init(&vm_committed_as, 0);
3096 VM_BUG_ON(ret);
David Howells8feae132009-01-08 12:04:47 +00003097}