]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mmap.c | |
3 | * | |
4 | * Written by obz. | |
5 | * | |
046c6884 | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
7 | */ |
8 | ||
9 | #include <linux/slab.h> | |
4af3c9cc | 10 | #include <linux/backing-dev.h> |
1da177e4 LT |
11 | #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> | |
c59ede7b | 17 | #include <linux/capability.h> |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/file.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/security.h> | |
6146f0d5 | 23 | #include <linux/ima.h> |
1da177e4 LT |
24 | #include <linux/hugetlb.h> |
25 | #include <linux/profile.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/mempolicy.h> | |
29 | #include <linux/rmap.h> | |
cddb8a5c | 30 | #include <linux/mmu_notifier.h> |
cdd6c482 | 31 | #include <linux/perf_event.h> |
1da177e4 LT |
32 | |
33 | #include <asm/uaccess.h> | |
34 | #include <asm/cacheflush.h> | |
35 | #include <asm/tlb.h> | |
d6dd61c8 | 36 | #include <asm/mmu_context.h> |
1da177e4 | 37 | |
42b77728 JB |
38 | #include "internal.h" |
39 | ||
3a459756 KK |
40 | #ifndef arch_mmap_check |
41 | #define arch_mmap_check(addr, len, flags) (0) | |
42 | #endif | |
43 | ||
08e7d9b5 MS |
44 | #ifndef arch_rebalance_pgtables |
45 | #define arch_rebalance_pgtables(addr, len) (addr) | |
46 | #endif | |
47 | ||
e0da382c HD |
48 | static void unmap_region(struct mm_struct *mm, |
49 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
50 | unsigned long start, unsigned long end); | |
51 | ||
1da177e4 LT |
52 | /* |
53 | * WARNING: the debugging will use recursive algorithms so never enable this | |
54 | * unless you know what you are doing. | |
55 | */ | |
56 | #undef DEBUG_MM_RB | |
57 | ||
58 | /* description of effects of mapping type and prot in current implementation. | |
59 | * this is due to the limited x86 page protection hardware. The expected | |
60 | * behavior is in parens: | |
61 | * | |
62 | * map_type prot | |
63 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
64 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
65 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
66 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
67 | * | |
68 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
69 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
70 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
71 | * | |
72 | */ | |
73 | pgprot_t protection_map[16] = { | |
74 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
75 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
76 | }; | |
77 | ||
804af2cf HD |
78 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
79 | { | |
b845f313 DK |
80 | return __pgprot(pgprot_val(protection_map[vm_flags & |
81 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
82 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
83 | } |
84 | EXPORT_SYMBOL(vm_get_page_prot); | |
85 | ||
1da177e4 LT |
86 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
87 | int sysctl_overcommit_ratio = 50; /* default is 50% */ | |
c3d8c141 | 88 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
00a62ce9 | 89 | struct percpu_counter vm_committed_as; |
1da177e4 LT |
90 | |
91 | /* | |
92 | * Check that a process has enough memory to allocate a new virtual | |
93 | * mapping. 0 means there is enough memory for the allocation to | |
94 | * succeed and -ENOMEM implies there is not. | |
95 | * | |
96 | * We currently support three overcommit policies, which are set via the | |
97 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
98 | * | |
99 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
100 | * Additional code 2002 Jul 20 by Robert Love. | |
101 | * | |
102 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
103 | * | |
104 | * Note this is a helper function intended to be used by LSMs which | |
105 | * wish to use this logic. | |
106 | */ | |
34b4e4aa | 107 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
108 | { |
109 | unsigned long free, allowed; | |
110 | ||
111 | vm_acct_memory(pages); | |
112 | ||
113 | /* | |
114 | * Sometimes we want to use more memory than we have | |
115 | */ | |
116 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
117 | return 0; | |
118 | ||
119 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
120 | unsigned long n; | |
121 | ||
347ce434 | 122 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
123 | free += nr_swap_pages; |
124 | ||
125 | /* | |
126 | * Any slabs which are created with the | |
127 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
128 | * which are reclaimable, under pressure. The dentry | |
129 | * cache and most inode caches should fall into this | |
130 | */ | |
972d1a7b | 131 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
132 | |
133 | /* | |
134 | * Leave the last 3% for root | |
135 | */ | |
136 | if (!cap_sys_admin) | |
137 | free -= free / 32; | |
138 | ||
139 | if (free > pages) | |
140 | return 0; | |
141 | ||
142 | /* | |
143 | * nr_free_pages() is very expensive on large systems, | |
144 | * only call if we're about to fail. | |
145 | */ | |
146 | n = nr_free_pages(); | |
6d9f7839 HA |
147 | |
148 | /* | |
149 | * Leave reserved pages. The pages are not for anonymous pages. | |
150 | */ | |
151 | if (n <= totalreserve_pages) | |
152 | goto error; | |
153 | else | |
154 | n -= totalreserve_pages; | |
155 | ||
156 | /* | |
157 | * Leave the last 3% for root | |
158 | */ | |
1da177e4 LT |
159 | if (!cap_sys_admin) |
160 | n -= n / 32; | |
161 | free += n; | |
162 | ||
163 | if (free > pages) | |
164 | return 0; | |
6d9f7839 HA |
165 | |
166 | goto error; | |
1da177e4 LT |
167 | } |
168 | ||
169 | allowed = (totalram_pages - hugetlb_total_pages()) | |
170 | * sysctl_overcommit_ratio / 100; | |
171 | /* | |
172 | * Leave the last 3% for root | |
173 | */ | |
174 | if (!cap_sys_admin) | |
175 | allowed -= allowed / 32; | |
176 | allowed += total_swap_pages; | |
177 | ||
178 | /* Don't let a single process grow too big: | |
179 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
180 | if (mm) |
181 | allowed -= mm->total_vm / 32; | |
1da177e4 | 182 | |
00a62ce9 | 183 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 184 | return 0; |
6d9f7839 | 185 | error: |
1da177e4 LT |
186 | vm_unacct_memory(pages); |
187 | ||
188 | return -ENOMEM; | |
189 | } | |
190 | ||
1da177e4 LT |
191 | /* |
192 | * Requires inode->i_mapping->i_mmap_lock | |
193 | */ | |
194 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
195 | struct file *file, struct address_space *mapping) | |
196 | { | |
197 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 198 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
199 | if (vma->vm_flags & VM_SHARED) |
200 | mapping->i_mmap_writable--; | |
201 | ||
202 | flush_dcache_mmap_lock(mapping); | |
203 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
204 | list_del_init(&vma->shared.vm_set.list); | |
205 | else | |
206 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
207 | flush_dcache_mmap_unlock(mapping); | |
208 | } | |
209 | ||
210 | /* | |
a8fb5618 HD |
211 | * Unlink a file-based vm structure from its prio_tree, to hide |
212 | * vma from rmap and vmtruncate before freeing its page tables. | |
1da177e4 | 213 | */ |
a8fb5618 | 214 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
215 | { |
216 | struct file *file = vma->vm_file; | |
217 | ||
1da177e4 LT |
218 | if (file) { |
219 | struct address_space *mapping = file->f_mapping; | |
220 | spin_lock(&mapping->i_mmap_lock); | |
221 | __remove_shared_vm_struct(vma, file, mapping); | |
222 | spin_unlock(&mapping->i_mmap_lock); | |
223 | } | |
a8fb5618 HD |
224 | } |
225 | ||
226 | /* | |
227 | * Close a vm structure and free it, returning the next. | |
228 | */ | |
229 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
230 | { | |
231 | struct vm_area_struct *next = vma->vm_next; | |
232 | ||
a8fb5618 | 233 | might_sleep(); |
1da177e4 LT |
234 | if (vma->vm_ops && vma->vm_ops->close) |
235 | vma->vm_ops->close(vma); | |
925d1c40 | 236 | if (vma->vm_file) { |
a8fb5618 | 237 | fput(vma->vm_file); |
925d1c40 MH |
238 | if (vma->vm_flags & VM_EXECUTABLE) |
239 | removed_exe_file_vma(vma->vm_mm); | |
240 | } | |
f0be3d32 | 241 | mpol_put(vma_policy(vma)); |
1da177e4 | 242 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 243 | return next; |
1da177e4 LT |
244 | } |
245 | ||
6a6160a7 | 246 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
247 | { |
248 | unsigned long rlim, retval; | |
249 | unsigned long newbrk, oldbrk; | |
250 | struct mm_struct *mm = current->mm; | |
a5b4592c | 251 | unsigned long min_brk; |
1da177e4 LT |
252 | |
253 | down_write(&mm->mmap_sem); | |
254 | ||
a5b4592c JK |
255 | #ifdef CONFIG_COMPAT_BRK |
256 | min_brk = mm->end_code; | |
257 | #else | |
258 | min_brk = mm->start_brk; | |
259 | #endif | |
260 | if (brk < min_brk) | |
1da177e4 | 261 | goto out; |
1e624196 RG |
262 | |
263 | /* | |
264 | * Check against rlimit here. If this check is done later after the test | |
265 | * of oldbrk with newbrk then it can escape the test and let the data | |
266 | * segment grow beyond its set limit the in case where the limit is | |
267 | * not page aligned -Ram Gupta | |
268 | */ | |
269 | rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; | |
c1d171a0 JK |
270 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
271 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
272 | goto out; |
273 | ||
1da177e4 LT |
274 | newbrk = PAGE_ALIGN(brk); |
275 | oldbrk = PAGE_ALIGN(mm->brk); | |
276 | if (oldbrk == newbrk) | |
277 | goto set_brk; | |
278 | ||
279 | /* Always allow shrinking brk. */ | |
280 | if (brk <= mm->brk) { | |
281 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
282 | goto set_brk; | |
283 | goto out; | |
284 | } | |
285 | ||
1da177e4 LT |
286 | /* Check against existing mmap mappings. */ |
287 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
288 | goto out; | |
289 | ||
290 | /* Ok, looks good - let it rip. */ | |
291 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
292 | goto out; | |
293 | set_brk: | |
294 | mm->brk = brk; | |
295 | out: | |
296 | retval = mm->brk; | |
297 | up_write(&mm->mmap_sem); | |
298 | return retval; | |
299 | } | |
300 | ||
301 | #ifdef DEBUG_MM_RB | |
302 | static int browse_rb(struct rb_root *root) | |
303 | { | |
304 | int i = 0, j; | |
305 | struct rb_node *nd, *pn = NULL; | |
306 | unsigned long prev = 0, pend = 0; | |
307 | ||
308 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
309 | struct vm_area_struct *vma; | |
310 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
311 | if (vma->vm_start < prev) | |
312 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
313 | if (vma->vm_start < pend) | |
314 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
315 | if (vma->vm_start > vma->vm_end) | |
316 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
317 | i++; | |
318 | pn = nd; | |
d1af65d1 DM |
319 | prev = vma->vm_start; |
320 | pend = vma->vm_end; | |
1da177e4 LT |
321 | } |
322 | j = 0; | |
323 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
324 | j++; | |
325 | } | |
326 | if (i != j) | |
327 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
328 | return i; | |
329 | } | |
330 | ||
331 | void validate_mm(struct mm_struct *mm) | |
332 | { | |
333 | int bug = 0; | |
334 | int i = 0; | |
335 | struct vm_area_struct *tmp = mm->mmap; | |
336 | while (tmp) { | |
337 | tmp = tmp->vm_next; | |
338 | i++; | |
339 | } | |
340 | if (i != mm->map_count) | |
341 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
342 | i = browse_rb(&mm->mm_rb); | |
343 | if (i != mm->map_count) | |
344 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 345 | BUG_ON(bug); |
1da177e4 LT |
346 | } |
347 | #else | |
348 | #define validate_mm(mm) do { } while (0) | |
349 | #endif | |
350 | ||
351 | static struct vm_area_struct * | |
352 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, | |
353 | struct vm_area_struct **pprev, struct rb_node ***rb_link, | |
354 | struct rb_node ** rb_parent) | |
355 | { | |
356 | struct vm_area_struct * vma; | |
357 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; | |
358 | ||
359 | __rb_link = &mm->mm_rb.rb_node; | |
360 | rb_prev = __rb_parent = NULL; | |
361 | vma = NULL; | |
362 | ||
363 | while (*__rb_link) { | |
364 | struct vm_area_struct *vma_tmp; | |
365 | ||
366 | __rb_parent = *__rb_link; | |
367 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
368 | ||
369 | if (vma_tmp->vm_end > addr) { | |
370 | vma = vma_tmp; | |
371 | if (vma_tmp->vm_start <= addr) | |
dfe195fb | 372 | break; |
1da177e4 LT |
373 | __rb_link = &__rb_parent->rb_left; |
374 | } else { | |
375 | rb_prev = __rb_parent; | |
376 | __rb_link = &__rb_parent->rb_right; | |
377 | } | |
378 | } | |
379 | ||
380 | *pprev = NULL; | |
381 | if (rb_prev) | |
382 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
383 | *rb_link = __rb_link; | |
384 | *rb_parent = __rb_parent; | |
385 | return vma; | |
386 | } | |
387 | ||
388 | static inline void | |
389 | __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, | |
390 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
391 | { | |
392 | if (prev) { | |
393 | vma->vm_next = prev->vm_next; | |
394 | prev->vm_next = vma; | |
395 | } else { | |
396 | mm->mmap = vma; | |
397 | if (rb_parent) | |
398 | vma->vm_next = rb_entry(rb_parent, | |
399 | struct vm_area_struct, vm_rb); | |
400 | else | |
401 | vma->vm_next = NULL; | |
402 | } | |
403 | } | |
404 | ||
405 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, | |
406 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
407 | { | |
408 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
409 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
410 | } | |
411 | ||
cb8f488c | 412 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 413 | { |
48aae425 | 414 | struct file *file; |
1da177e4 LT |
415 | |
416 | file = vma->vm_file; | |
417 | if (file) { | |
418 | struct address_space *mapping = file->f_mapping; | |
419 | ||
420 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 421 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
422 | if (vma->vm_flags & VM_SHARED) |
423 | mapping->i_mmap_writable++; | |
424 | ||
425 | flush_dcache_mmap_lock(mapping); | |
426 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
427 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
428 | else | |
429 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
430 | flush_dcache_mmap_unlock(mapping); | |
431 | } | |
432 | } | |
433 | ||
434 | static void | |
435 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
436 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
437 | struct rb_node *rb_parent) | |
438 | { | |
439 | __vma_link_list(mm, vma, prev, rb_parent); | |
440 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
441 | __anon_vma_link(vma); | |
442 | } | |
443 | ||
444 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
445 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
446 | struct rb_node *rb_parent) | |
447 | { | |
448 | struct address_space *mapping = NULL; | |
449 | ||
450 | if (vma->vm_file) | |
451 | mapping = vma->vm_file->f_mapping; | |
452 | ||
453 | if (mapping) { | |
454 | spin_lock(&mapping->i_mmap_lock); | |
455 | vma->vm_truncate_count = mapping->truncate_count; | |
456 | } | |
457 | anon_vma_lock(vma); | |
458 | ||
459 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
460 | __vma_link_file(vma); | |
461 | ||
462 | anon_vma_unlock(vma); | |
463 | if (mapping) | |
464 | spin_unlock(&mapping->i_mmap_lock); | |
465 | ||
466 | mm->map_count++; | |
467 | validate_mm(mm); | |
468 | } | |
469 | ||
470 | /* | |
471 | * Helper for vma_adjust in the split_vma insert case: | |
472 | * insert vm structure into list and rbtree and anon_vma, | |
473 | * but it has already been inserted into prio_tree earlier. | |
474 | */ | |
48aae425 | 475 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 476 | { |
48aae425 Z |
477 | struct vm_area_struct *__vma, *prev; |
478 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
479 | |
480 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); | |
46a350ef | 481 | BUG_ON(__vma && __vma->vm_start < vma->vm_end); |
1da177e4 LT |
482 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
483 | mm->map_count++; | |
484 | } | |
485 | ||
486 | static inline void | |
487 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
488 | struct vm_area_struct *prev) | |
489 | { | |
490 | prev->vm_next = vma->vm_next; | |
491 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
492 | if (mm->mmap_cache == vma) | |
493 | mm->mmap_cache = prev; | |
494 | } | |
495 | ||
496 | /* | |
497 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
498 | * is already present in an i_mmap tree without adjusting the tree. | |
499 | * The following helper function should be used when such adjustments | |
500 | * are necessary. The "insert" vma (if any) is to be inserted | |
501 | * before we drop the necessary locks. | |
502 | */ | |
503 | void vma_adjust(struct vm_area_struct *vma, unsigned long start, | |
504 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) | |
505 | { | |
506 | struct mm_struct *mm = vma->vm_mm; | |
507 | struct vm_area_struct *next = vma->vm_next; | |
508 | struct vm_area_struct *importer = NULL; | |
509 | struct address_space *mapping = NULL; | |
510 | struct prio_tree_root *root = NULL; | |
511 | struct file *file = vma->vm_file; | |
512 | struct anon_vma *anon_vma = NULL; | |
513 | long adjust_next = 0; | |
514 | int remove_next = 0; | |
515 | ||
516 | if (next && !insert) { | |
517 | if (end >= next->vm_end) { | |
518 | /* | |
519 | * vma expands, overlapping all the next, and | |
520 | * perhaps the one after too (mprotect case 6). | |
521 | */ | |
522 | again: remove_next = 1 + (end > next->vm_end); | |
523 | end = next->vm_end; | |
524 | anon_vma = next->anon_vma; | |
525 | importer = vma; | |
526 | } else if (end > next->vm_start) { | |
527 | /* | |
528 | * vma expands, overlapping part of the next: | |
529 | * mprotect case 5 shifting the boundary up. | |
530 | */ | |
531 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
532 | anon_vma = next->anon_vma; | |
533 | importer = vma; | |
534 | } else if (end < vma->vm_end) { | |
535 | /* | |
536 | * vma shrinks, and !insert tells it's not | |
537 | * split_vma inserting another: so it must be | |
538 | * mprotect case 4 shifting the boundary down. | |
539 | */ | |
540 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
541 | anon_vma = next->anon_vma; | |
542 | importer = next; | |
543 | } | |
544 | } | |
545 | ||
546 | if (file) { | |
547 | mapping = file->f_mapping; | |
548 | if (!(vma->vm_flags & VM_NONLINEAR)) | |
549 | root = &mapping->i_mmap; | |
550 | spin_lock(&mapping->i_mmap_lock); | |
551 | if (importer && | |
552 | vma->vm_truncate_count != next->vm_truncate_count) { | |
553 | /* | |
554 | * unmap_mapping_range might be in progress: | |
555 | * ensure that the expanding vma is rescanned. | |
556 | */ | |
557 | importer->vm_truncate_count = 0; | |
558 | } | |
559 | if (insert) { | |
560 | insert->vm_truncate_count = vma->vm_truncate_count; | |
561 | /* | |
562 | * Put into prio_tree now, so instantiated pages | |
563 | * are visible to arm/parisc __flush_dcache_page | |
564 | * throughout; but we cannot insert into address | |
565 | * space until vma start or end is updated. | |
566 | */ | |
567 | __vma_link_file(insert); | |
568 | } | |
569 | } | |
570 | ||
571 | /* | |
572 | * When changing only vma->vm_end, we don't really need | |
573 | * anon_vma lock: but is that case worth optimizing out? | |
574 | */ | |
575 | if (vma->anon_vma) | |
576 | anon_vma = vma->anon_vma; | |
577 | if (anon_vma) { | |
578 | spin_lock(&anon_vma->lock); | |
579 | /* | |
580 | * Easily overlooked: when mprotect shifts the boundary, | |
581 | * make sure the expanding vma has anon_vma set if the | |
582 | * shrinking vma had, to cover any anon pages imported. | |
583 | */ | |
584 | if (importer && !importer->anon_vma) { | |
585 | importer->anon_vma = anon_vma; | |
586 | __anon_vma_link(importer); | |
587 | } | |
588 | } | |
589 | ||
590 | if (root) { | |
591 | flush_dcache_mmap_lock(mapping); | |
592 | vma_prio_tree_remove(vma, root); | |
593 | if (adjust_next) | |
594 | vma_prio_tree_remove(next, root); | |
595 | } | |
596 | ||
597 | vma->vm_start = start; | |
598 | vma->vm_end = end; | |
599 | vma->vm_pgoff = pgoff; | |
600 | if (adjust_next) { | |
601 | next->vm_start += adjust_next << PAGE_SHIFT; | |
602 | next->vm_pgoff += adjust_next; | |
603 | } | |
604 | ||
605 | if (root) { | |
606 | if (adjust_next) | |
607 | vma_prio_tree_insert(next, root); | |
608 | vma_prio_tree_insert(vma, root); | |
609 | flush_dcache_mmap_unlock(mapping); | |
610 | } | |
611 | ||
612 | if (remove_next) { | |
613 | /* | |
614 | * vma_merge has merged next into vma, and needs | |
615 | * us to remove next before dropping the locks. | |
616 | */ | |
617 | __vma_unlink(mm, next, vma); | |
618 | if (file) | |
619 | __remove_shared_vm_struct(next, file, mapping); | |
620 | if (next->anon_vma) | |
621 | __anon_vma_merge(vma, next); | |
622 | } else if (insert) { | |
623 | /* | |
624 | * split_vma has split insert from vma, and needs | |
625 | * us to insert it before dropping the locks | |
626 | * (it may either follow vma or precede it). | |
627 | */ | |
628 | __insert_vm_struct(mm, insert); | |
629 | } | |
630 | ||
631 | if (anon_vma) | |
632 | spin_unlock(&anon_vma->lock); | |
633 | if (mapping) | |
634 | spin_unlock(&mapping->i_mmap_lock); | |
635 | ||
636 | if (remove_next) { | |
925d1c40 | 637 | if (file) { |
1da177e4 | 638 | fput(file); |
925d1c40 MH |
639 | if (next->vm_flags & VM_EXECUTABLE) |
640 | removed_exe_file_vma(mm); | |
641 | } | |
1da177e4 | 642 | mm->map_count--; |
f0be3d32 | 643 | mpol_put(vma_policy(next)); |
1da177e4 LT |
644 | kmem_cache_free(vm_area_cachep, next); |
645 | /* | |
646 | * In mprotect's case 6 (see comments on vma_merge), | |
647 | * we must remove another next too. It would clutter | |
648 | * up the code too much to do both in one go. | |
649 | */ | |
650 | if (remove_next == 2) { | |
651 | next = vma->vm_next; | |
652 | goto again; | |
653 | } | |
654 | } | |
655 | ||
656 | validate_mm(mm); | |
657 | } | |
658 | ||
659 | /* | |
660 | * If the vma has a ->close operation then the driver probably needs to release | |
661 | * per-vma resources, so we don't attempt to merge those. | |
662 | */ | |
1da177e4 LT |
663 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
664 | struct file *file, unsigned long vm_flags) | |
665 | { | |
8314c4f2 HD |
666 | /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ |
667 | if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) | |
1da177e4 LT |
668 | return 0; |
669 | if (vma->vm_file != file) | |
670 | return 0; | |
671 | if (vma->vm_ops && vma->vm_ops->close) | |
672 | return 0; | |
673 | return 1; | |
674 | } | |
675 | ||
676 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
677 | struct anon_vma *anon_vma2) | |
678 | { | |
679 | return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); | |
680 | } | |
681 | ||
682 | /* | |
683 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
684 | * in front of (at a lower virtual address and file offset than) the vma. | |
685 | * | |
686 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
687 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
688 | * | |
689 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
690 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
691 | * wrap, nor mmaps which cover the final page at index -1UL. | |
692 | */ | |
693 | static int | |
694 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
695 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
696 | { | |
697 | if (is_mergeable_vma(vma, file, vm_flags) && | |
698 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
699 | if (vma->vm_pgoff == vm_pgoff) | |
700 | return 1; | |
701 | } | |
702 | return 0; | |
703 | } | |
704 | ||
705 | /* | |
706 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
707 | * beyond (at a higher virtual address and file offset than) the vma. | |
708 | * | |
709 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
710 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
711 | */ | |
712 | static int | |
713 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
714 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
715 | { | |
716 | if (is_mergeable_vma(vma, file, vm_flags) && | |
717 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
718 | pgoff_t vm_pglen; | |
719 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
720 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
721 | return 1; | |
722 | } | |
723 | return 0; | |
724 | } | |
725 | ||
726 | /* | |
727 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
728 | * whether that can be merged with its predecessor or its successor. | |
729 | * Or both (it neatly fills a hole). | |
730 | * | |
731 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
732 | * certain not to be mapped by the time vma_merge is called; but when | |
733 | * called for mprotect, it is certain to be already mapped (either at | |
734 | * an offset within prev, or at the start of next), and the flags of | |
735 | * this area are about to be changed to vm_flags - and the no-change | |
736 | * case has already been eliminated. | |
737 | * | |
738 | * The following mprotect cases have to be considered, where AAAA is | |
739 | * the area passed down from mprotect_fixup, never extending beyond one | |
740 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
741 | * | |
742 | * AAAA AAAA AAAA AAAA | |
743 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
744 | * cannot merge might become might become might become | |
745 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
746 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
747 | * mremap move: PPPPNNNNNNNN 8 | |
748 | * AAAA | |
749 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
750 | * might become case 1 below case 2 below case 3 below | |
751 | * | |
752 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
753 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
754 | */ | |
755 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
756 | struct vm_area_struct *prev, unsigned long addr, | |
757 | unsigned long end, unsigned long vm_flags, | |
758 | struct anon_vma *anon_vma, struct file *file, | |
759 | pgoff_t pgoff, struct mempolicy *policy) | |
760 | { | |
761 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
762 | struct vm_area_struct *area, *next; | |
763 | ||
764 | /* | |
765 | * We later require that vma->vm_flags == vm_flags, | |
766 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
767 | */ | |
768 | if (vm_flags & VM_SPECIAL) | |
769 | return NULL; | |
770 | ||
771 | if (prev) | |
772 | next = prev->vm_next; | |
773 | else | |
774 | next = mm->mmap; | |
775 | area = next; | |
776 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
777 | next = next->vm_next; | |
778 | ||
779 | /* | |
780 | * Can it merge with the predecessor? | |
781 | */ | |
782 | if (prev && prev->vm_end == addr && | |
783 | mpol_equal(vma_policy(prev), policy) && | |
784 | can_vma_merge_after(prev, vm_flags, | |
785 | anon_vma, file, pgoff)) { | |
786 | /* | |
787 | * OK, it can. Can we now merge in the successor as well? | |
788 | */ | |
789 | if (next && end == next->vm_start && | |
790 | mpol_equal(policy, vma_policy(next)) && | |
791 | can_vma_merge_before(next, vm_flags, | |
792 | anon_vma, file, pgoff+pglen) && | |
793 | is_mergeable_anon_vma(prev->anon_vma, | |
794 | next->anon_vma)) { | |
795 | /* cases 1, 6 */ | |
796 | vma_adjust(prev, prev->vm_start, | |
797 | next->vm_end, prev->vm_pgoff, NULL); | |
798 | } else /* cases 2, 5, 7 */ | |
799 | vma_adjust(prev, prev->vm_start, | |
800 | end, prev->vm_pgoff, NULL); | |
801 | return prev; | |
802 | } | |
803 | ||
804 | /* | |
805 | * Can this new request be merged in front of next? | |
806 | */ | |
807 | if (next && end == next->vm_start && | |
808 | mpol_equal(policy, vma_policy(next)) && | |
809 | can_vma_merge_before(next, vm_flags, | |
810 | anon_vma, file, pgoff+pglen)) { | |
811 | if (prev && addr < prev->vm_end) /* case 4 */ | |
812 | vma_adjust(prev, prev->vm_start, | |
813 | addr, prev->vm_pgoff, NULL); | |
814 | else /* cases 3, 8 */ | |
815 | vma_adjust(area, addr, next->vm_end, | |
816 | next->vm_pgoff - pglen, NULL); | |
817 | return area; | |
818 | } | |
819 | ||
820 | return NULL; | |
821 | } | |
822 | ||
823 | /* | |
824 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
825 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
826 | * to allocate a new anon_vma. It checks because a repetitive | |
827 | * sequence of mprotects and faults may otherwise lead to distinct | |
828 | * anon_vmas being allocated, preventing vma merge in subsequent | |
829 | * mprotect. | |
830 | */ | |
831 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
832 | { | |
833 | struct vm_area_struct *near; | |
834 | unsigned long vm_flags; | |
835 | ||
836 | near = vma->vm_next; | |
837 | if (!near) | |
838 | goto try_prev; | |
839 | ||
840 | /* | |
841 | * Since only mprotect tries to remerge vmas, match flags | |
842 | * which might be mprotected into each other later on. | |
843 | * Neither mlock nor madvise tries to remerge at present, | |
844 | * so leave their flags as obstructing a merge. | |
845 | */ | |
846 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
847 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
848 | ||
849 | if (near->anon_vma && vma->vm_end == near->vm_start && | |
850 | mpol_equal(vma_policy(vma), vma_policy(near)) && | |
851 | can_vma_merge_before(near, vm_flags, | |
852 | NULL, vma->vm_file, vma->vm_pgoff + | |
853 | ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) | |
854 | return near->anon_vma; | |
855 | try_prev: | |
856 | /* | |
857 | * It is potentially slow to have to call find_vma_prev here. | |
858 | * But it's only on the first write fault on the vma, not | |
859 | * every time, and we could devise a way to avoid it later | |
860 | * (e.g. stash info in next's anon_vma_node when assigning | |
861 | * an anon_vma, or when trying vma_merge). Another time. | |
862 | */ | |
46a350ef | 863 | BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma); |
1da177e4 LT |
864 | if (!near) |
865 | goto none; | |
866 | ||
867 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
868 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
869 | ||
870 | if (near->anon_vma && near->vm_end == vma->vm_start && | |
871 | mpol_equal(vma_policy(near), vma_policy(vma)) && | |
872 | can_vma_merge_after(near, vm_flags, | |
873 | NULL, vma->vm_file, vma->vm_pgoff)) | |
874 | return near->anon_vma; | |
875 | none: | |
876 | /* | |
877 | * There's no absolute need to look only at touching neighbours: | |
878 | * we could search further afield for "compatible" anon_vmas. | |
879 | * But it would probably just be a waste of time searching, | |
880 | * or lead to too many vmas hanging off the same anon_vma. | |
881 | * We're trying to allow mprotect remerging later on, | |
882 | * not trying to minimize memory used for anon_vmas. | |
883 | */ | |
884 | return NULL; | |
885 | } | |
886 | ||
887 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 888 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
889 | struct file *file, long pages) |
890 | { | |
891 | const unsigned long stack_flags | |
892 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
893 | ||
1da177e4 LT |
894 | if (file) { |
895 | mm->shared_vm += pages; | |
896 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
897 | mm->exec_vm += pages; | |
898 | } else if (flags & stack_flags) | |
899 | mm->stack_vm += pages; | |
900 | if (flags & (VM_RESERVED|VM_IO)) | |
901 | mm->reserved_vm += pages; | |
902 | } | |
903 | #endif /* CONFIG_PROC_FS */ | |
904 | ||
905 | /* | |
27f5de79 | 906 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
907 | */ |
908 | ||
48aae425 | 909 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 LT |
910 | unsigned long len, unsigned long prot, |
911 | unsigned long flags, unsigned long pgoff) | |
912 | { | |
913 | struct mm_struct * mm = current->mm; | |
1da177e4 LT |
914 | struct inode *inode; |
915 | unsigned int vm_flags; | |
1da177e4 | 916 | int error; |
0165ab44 | 917 | unsigned long reqprot = prot; |
1da177e4 | 918 | |
1da177e4 LT |
919 | /* |
920 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
921 | * | |
922 | * (the exception is when the underlying filesystem is noexec | |
923 | * mounted, in which case we dont add PROT_EXEC.) | |
924 | */ | |
925 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 926 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
927 | prot |= PROT_EXEC; |
928 | ||
929 | if (!len) | |
930 | return -EINVAL; | |
931 | ||
7cd94146 EP |
932 | if (!(flags & MAP_FIXED)) |
933 | addr = round_hint_to_min(addr); | |
934 | ||
3a459756 KK |
935 | error = arch_mmap_check(addr, len, flags); |
936 | if (error) | |
937 | return error; | |
938 | ||
1da177e4 LT |
939 | /* Careful about overflows.. */ |
940 | len = PAGE_ALIGN(len); | |
941 | if (!len || len > TASK_SIZE) | |
942 | return -ENOMEM; | |
943 | ||
944 | /* offset overflow? */ | |
945 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
946 | return -EOVERFLOW; | |
947 | ||
948 | /* Too many mappings? */ | |
949 | if (mm->map_count > sysctl_max_map_count) | |
950 | return -ENOMEM; | |
951 | ||
952 | /* Obtain the address to map to. we verify (or select) it and ensure | |
953 | * that it represents a valid section of the address space. | |
954 | */ | |
955 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
956 | if (addr & ~PAGE_MASK) | |
957 | return addr; | |
958 | ||
959 | /* Do simple checking here so the lower-level routines won't have | |
960 | * to. we assume access permissions have been handled by the open | |
961 | * of the memory object, so we don't do any here. | |
962 | */ | |
963 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
964 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
965 | ||
966 | if (flags & MAP_LOCKED) { | |
967 | if (!can_do_mlock()) | |
968 | return -EPERM; | |
969 | vm_flags |= VM_LOCKED; | |
970 | } | |
ba470de4 | 971 | |
1da177e4 LT |
972 | /* mlock MCL_FUTURE? */ |
973 | if (vm_flags & VM_LOCKED) { | |
974 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
975 | locked = len >> PAGE_SHIFT; |
976 | locked += mm->locked_vm; | |
1da177e4 | 977 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 978 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
979 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
980 | return -EAGAIN; | |
981 | } | |
982 | ||
d3ac7f89 | 983 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
984 | |
985 | if (file) { | |
986 | switch (flags & MAP_TYPE) { | |
987 | case MAP_SHARED: | |
988 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
989 | return -EACCES; | |
990 | ||
991 | /* | |
992 | * Make sure we don't allow writing to an append-only | |
993 | * file.. | |
994 | */ | |
995 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
996 | return -EACCES; | |
997 | ||
998 | /* | |
999 | * Make sure there are no mandatory locks on the file. | |
1000 | */ | |
1001 | if (locks_verify_locked(inode)) | |
1002 | return -EAGAIN; | |
1003 | ||
1004 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1005 | if (!(file->f_mode & FMODE_WRITE)) | |
1006 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1007 | ||
1008 | /* fall through */ | |
1009 | case MAP_PRIVATE: | |
1010 | if (!(file->f_mode & FMODE_READ)) | |
1011 | return -EACCES; | |
d3ac7f89 | 1012 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1013 | if (vm_flags & VM_EXEC) |
1014 | return -EPERM; | |
1015 | vm_flags &= ~VM_MAYEXEC; | |
1016 | } | |
80c5606c LT |
1017 | |
1018 | if (!file->f_op || !file->f_op->mmap) | |
1019 | return -ENODEV; | |
1da177e4 LT |
1020 | break; |
1021 | ||
1022 | default: | |
1023 | return -EINVAL; | |
1024 | } | |
1025 | } else { | |
1026 | switch (flags & MAP_TYPE) { | |
1027 | case MAP_SHARED: | |
ce363942 TH |
1028 | /* |
1029 | * Ignore pgoff. | |
1030 | */ | |
1031 | pgoff = 0; | |
1da177e4 LT |
1032 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1033 | break; | |
1034 | case MAP_PRIVATE: | |
1035 | /* | |
1036 | * Set pgoff according to addr for anon_vma. | |
1037 | */ | |
1038 | pgoff = addr >> PAGE_SHIFT; | |
1039 | break; | |
1040 | default: | |
1041 | return -EINVAL; | |
1042 | } | |
1043 | } | |
1044 | ||
ed032189 | 1045 | error = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
6146f0d5 MZ |
1046 | if (error) |
1047 | return error; | |
1048 | error = ima_file_mmap(file, prot); | |
1da177e4 LT |
1049 | if (error) |
1050 | return error; | |
ed032189 | 1051 | |
5a6fe125 | 1052 | return mmap_region(file, addr, len, flags, vm_flags, pgoff); |
0165ab44 MS |
1053 | } |
1054 | EXPORT_SYMBOL(do_mmap_pgoff); | |
1055 | ||
4e950f6f AD |
1056 | /* |
1057 | * Some shared mappigns will want the pages marked read-only | |
1058 | * to track write events. If so, we'll downgrade vm_page_prot | |
1059 | * to the private version (using protection_map[] without the | |
1060 | * VM_SHARED bit). | |
1061 | */ | |
1062 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1063 | { | |
1064 | unsigned int vm_flags = vma->vm_flags; | |
1065 | ||
1066 | /* If it was private or non-writable, the write bit is already clear */ | |
1067 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1068 | return 0; | |
1069 | ||
1070 | /* The backer wishes to know when pages are first written to? */ | |
1071 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1072 | return 1; | |
1073 | ||
1074 | /* The open routine did something to the protections already? */ | |
1075 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1076 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1077 | return 0; |
1078 | ||
1079 | /* Specialty mapping? */ | |
1080 | if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) | |
1081 | return 0; | |
1082 | ||
1083 | /* Can the mapping track the dirty pages? */ | |
1084 | return vma->vm_file && vma->vm_file->f_mapping && | |
1085 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1086 | } | |
1087 | ||
fc8744ad LT |
1088 | /* |
1089 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1090 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1091 | */ |
5a6fe125 | 1092 | static inline int accountable_mapping(struct file *file, unsigned int vm_flags) |
fc8744ad | 1093 | { |
5a6fe125 MG |
1094 | /* |
1095 | * hugetlb has its own accounting separate from the core VM | |
1096 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1097 | */ | |
1098 | if (file && is_file_hugepages(file)) | |
1099 | return 0; | |
1100 | ||
fc8744ad LT |
1101 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1102 | } | |
1103 | ||
0165ab44 MS |
1104 | unsigned long mmap_region(struct file *file, unsigned long addr, |
1105 | unsigned long len, unsigned long flags, | |
5a6fe125 | 1106 | unsigned int vm_flags, unsigned long pgoff) |
0165ab44 MS |
1107 | { |
1108 | struct mm_struct *mm = current->mm; | |
1109 | struct vm_area_struct *vma, *prev; | |
1110 | int correct_wcount = 0; | |
1111 | int error; | |
1112 | struct rb_node **rb_link, *rb_parent; | |
1113 | unsigned long charged = 0; | |
1114 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; | |
1115 | ||
1da177e4 LT |
1116 | /* Clear old maps */ |
1117 | error = -ENOMEM; | |
1118 | munmap_back: | |
1119 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1120 | if (vma && vma->vm_start < addr + len) { | |
1121 | if (do_munmap(mm, addr, len)) | |
1122 | return -ENOMEM; | |
1123 | goto munmap_back; | |
1124 | } | |
1125 | ||
1126 | /* Check against address space limit. */ | |
119f657c | 1127 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1128 | return -ENOMEM; |
1129 | ||
fc8744ad LT |
1130 | /* |
1131 | * Set 'VM_NORESERVE' if we should not account for the | |
5a6fe125 | 1132 | * memory use of this mapping. |
fc8744ad | 1133 | */ |
5a6fe125 MG |
1134 | if ((flags & MAP_NORESERVE)) { |
1135 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1136 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1137 | vm_flags |= VM_NORESERVE; | |
1138 | ||
1139 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1140 | if (file && is_file_hugepages(file)) | |
1141 | vm_flags |= VM_NORESERVE; | |
1142 | } | |
cdfd4325 | 1143 | |
fc8744ad LT |
1144 | /* |
1145 | * Private writable mapping: check memory availability | |
1146 | */ | |
5a6fe125 | 1147 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad LT |
1148 | charged = len >> PAGE_SHIFT; |
1149 | if (security_vm_enough_memory(charged)) | |
1150 | return -ENOMEM; | |
1151 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1152 | } |
1153 | ||
1154 | /* | |
de33c8db | 1155 | * Can we just expand an old mapping? |
1da177e4 | 1156 | */ |
de33c8db LT |
1157 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1158 | if (vma) | |
1159 | goto out; | |
1da177e4 LT |
1160 | |
1161 | /* | |
1162 | * Determine the object being mapped and call the appropriate | |
1163 | * specific mapper. the address has already been validated, but | |
1164 | * not unmapped, but the maps are removed from the list. | |
1165 | */ | |
c5e3b83e | 1166 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1167 | if (!vma) { |
1168 | error = -ENOMEM; | |
1169 | goto unacct_error; | |
1170 | } | |
1da177e4 LT |
1171 | |
1172 | vma->vm_mm = mm; | |
1173 | vma->vm_start = addr; | |
1174 | vma->vm_end = addr + len; | |
1175 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1176 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 LT |
1177 | vma->vm_pgoff = pgoff; |
1178 | ||
1179 | if (file) { | |
1180 | error = -EINVAL; | |
1181 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) | |
1182 | goto free_vma; | |
1183 | if (vm_flags & VM_DENYWRITE) { | |
1184 | error = deny_write_access(file); | |
1185 | if (error) | |
1186 | goto free_vma; | |
1187 | correct_wcount = 1; | |
1188 | } | |
1189 | vma->vm_file = file; | |
1190 | get_file(file); | |
1191 | error = file->f_op->mmap(file, vma); | |
1192 | if (error) | |
1193 | goto unmap_and_free_vma; | |
925d1c40 MH |
1194 | if (vm_flags & VM_EXECUTABLE) |
1195 | added_exe_file_vma(mm); | |
1da177e4 LT |
1196 | } else if (vm_flags & VM_SHARED) { |
1197 | error = shmem_zero_setup(vma); | |
1198 | if (error) | |
1199 | goto free_vma; | |
1200 | } | |
1201 | ||
1da177e4 LT |
1202 | /* Can addr have changed?? |
1203 | * | |
1204 | * Answer: Yes, several device drivers can do it in their | |
1205 | * f_op->mmap method. -DaveM | |
1206 | */ | |
1207 | addr = vma->vm_start; | |
1208 | pgoff = vma->vm_pgoff; | |
1209 | vm_flags = vma->vm_flags; | |
1210 | ||
d08b3851 | 1211 | if (vma_wants_writenotify(vma)) |
1ddd439e | 1212 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
d08b3851 | 1213 | |
de33c8db LT |
1214 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1215 | file = vma->vm_file; | |
4d3d5b41 ON |
1216 | |
1217 | /* Once vma denies write, undo our temporary denial count */ | |
1218 | if (correct_wcount) | |
1219 | atomic_inc(&inode->i_writecount); | |
1220 | out: | |
cdd6c482 | 1221 | perf_event_mmap(vma); |
0a4a9391 | 1222 | |
1da177e4 | 1223 | mm->total_vm += len >> PAGE_SHIFT; |
ab50b8ed | 1224 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1225 | if (vm_flags & VM_LOCKED) { |
ba470de4 RR |
1226 | /* |
1227 | * makes pages present; downgrades, drops, reacquires mmap_sem | |
1228 | */ | |
1229 | long nr_pages = mlock_vma_pages_range(vma, addr, addr + len); | |
1230 | if (nr_pages < 0) | |
1231 | return nr_pages; /* vma gone! */ | |
1232 | mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages; | |
1233 | } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) | |
54cb8821 | 1234 | make_pages_present(addr, addr + len); |
1da177e4 LT |
1235 | return addr; |
1236 | ||
1237 | unmap_and_free_vma: | |
1238 | if (correct_wcount) | |
1239 | atomic_inc(&inode->i_writecount); | |
1240 | vma->vm_file = NULL; | |
1241 | fput(file); | |
1242 | ||
1243 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1244 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1245 | charged = 0; | |
1da177e4 LT |
1246 | free_vma: |
1247 | kmem_cache_free(vm_area_cachep, vma); | |
1248 | unacct_error: | |
1249 | if (charged) | |
1250 | vm_unacct_memory(charged); | |
1251 | return error; | |
1252 | } | |
1253 | ||
1da177e4 LT |
1254 | /* Get an address range which is currently unmapped. |
1255 | * For shmat() with addr=0. | |
1256 | * | |
1257 | * Ugly calling convention alert: | |
1258 | * Return value with the low bits set means error value, | |
1259 | * ie | |
1260 | * if (ret & ~PAGE_MASK) | |
1261 | * error = ret; | |
1262 | * | |
1263 | * This function "knows" that -ENOMEM has the bits set. | |
1264 | */ | |
1265 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1266 | unsigned long | |
1267 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1268 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1269 | { | |
1270 | struct mm_struct *mm = current->mm; | |
1271 | struct vm_area_struct *vma; | |
1272 | unsigned long start_addr; | |
1273 | ||
1274 | if (len > TASK_SIZE) | |
1275 | return -ENOMEM; | |
1276 | ||
06abdfb4 BH |
1277 | if (flags & MAP_FIXED) |
1278 | return addr; | |
1279 | ||
1da177e4 LT |
1280 | if (addr) { |
1281 | addr = PAGE_ALIGN(addr); | |
1282 | vma = find_vma(mm, addr); | |
1283 | if (TASK_SIZE - len >= addr && | |
1284 | (!vma || addr + len <= vma->vm_start)) | |
1285 | return addr; | |
1286 | } | |
1363c3cd WW |
1287 | if (len > mm->cached_hole_size) { |
1288 | start_addr = addr = mm->free_area_cache; | |
1289 | } else { | |
1290 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1291 | mm->cached_hole_size = 0; | |
1292 | } | |
1da177e4 LT |
1293 | |
1294 | full_search: | |
1295 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1296 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1297 | if (TASK_SIZE - len < addr) { | |
1298 | /* | |
1299 | * Start a new search - just in case we missed | |
1300 | * some holes. | |
1301 | */ | |
1302 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1303 | addr = TASK_UNMAPPED_BASE; |
1304 | start_addr = addr; | |
1305 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1306 | goto full_search; |
1307 | } | |
1308 | return -ENOMEM; | |
1309 | } | |
1310 | if (!vma || addr + len <= vma->vm_start) { | |
1311 | /* | |
1312 | * Remember the place where we stopped the search: | |
1313 | */ | |
1314 | mm->free_area_cache = addr + len; | |
1315 | return addr; | |
1316 | } | |
1363c3cd WW |
1317 | if (addr + mm->cached_hole_size < vma->vm_start) |
1318 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1319 | addr = vma->vm_end; |
1320 | } | |
1321 | } | |
1322 | #endif | |
1323 | ||
1363c3cd | 1324 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1325 | { |
1326 | /* | |
1327 | * Is this a new hole at the lowest possible address? | |
1328 | */ | |
1363c3cd WW |
1329 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { |
1330 | mm->free_area_cache = addr; | |
1331 | mm->cached_hole_size = ~0UL; | |
1332 | } | |
1da177e4 LT |
1333 | } |
1334 | ||
1335 | /* | |
1336 | * This mmap-allocator allocates new areas top-down from below the | |
1337 | * stack's low limit (the base): | |
1338 | */ | |
1339 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1340 | unsigned long | |
1341 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1342 | const unsigned long len, const unsigned long pgoff, | |
1343 | const unsigned long flags) | |
1344 | { | |
1345 | struct vm_area_struct *vma; | |
1346 | struct mm_struct *mm = current->mm; | |
1347 | unsigned long addr = addr0; | |
1348 | ||
1349 | /* requested length too big for entire address space */ | |
1350 | if (len > TASK_SIZE) | |
1351 | return -ENOMEM; | |
1352 | ||
06abdfb4 BH |
1353 | if (flags & MAP_FIXED) |
1354 | return addr; | |
1355 | ||
1da177e4 LT |
1356 | /* requesting a specific address */ |
1357 | if (addr) { | |
1358 | addr = PAGE_ALIGN(addr); | |
1359 | vma = find_vma(mm, addr); | |
1360 | if (TASK_SIZE - len >= addr && | |
1361 | (!vma || addr + len <= vma->vm_start)) | |
1362 | return addr; | |
1363 | } | |
1364 | ||
1363c3cd WW |
1365 | /* check if free_area_cache is useful for us */ |
1366 | if (len <= mm->cached_hole_size) { | |
1367 | mm->cached_hole_size = 0; | |
1368 | mm->free_area_cache = mm->mmap_base; | |
1369 | } | |
1370 | ||
1da177e4 LT |
1371 | /* either no address requested or can't fit in requested address hole */ |
1372 | addr = mm->free_area_cache; | |
1373 | ||
1374 | /* make sure it can fit in the remaining address space */ | |
49a43876 | 1375 | if (addr > len) { |
1da177e4 LT |
1376 | vma = find_vma(mm, addr-len); |
1377 | if (!vma || addr <= vma->vm_start) | |
1378 | /* remember the address as a hint for next time */ | |
1379 | return (mm->free_area_cache = addr-len); | |
1380 | } | |
1381 | ||
73219d17 CW |
1382 | if (mm->mmap_base < len) |
1383 | goto bottomup; | |
1384 | ||
1da177e4 LT |
1385 | addr = mm->mmap_base-len; |
1386 | ||
1387 | do { | |
1388 | /* | |
1389 | * Lookup failure means no vma is above this address, | |
1390 | * else if new region fits below vma->vm_start, | |
1391 | * return with success: | |
1392 | */ | |
1393 | vma = find_vma(mm, addr); | |
1394 | if (!vma || addr+len <= vma->vm_start) | |
1395 | /* remember the address as a hint for next time */ | |
1396 | return (mm->free_area_cache = addr); | |
1397 | ||
1363c3cd WW |
1398 | /* remember the largest hole we saw so far */ |
1399 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1400 | mm->cached_hole_size = vma->vm_start - addr; | |
1401 | ||
1da177e4 LT |
1402 | /* try just below the current vma->vm_start */ |
1403 | addr = vma->vm_start-len; | |
49a43876 | 1404 | } while (len < vma->vm_start); |
1da177e4 | 1405 | |
73219d17 | 1406 | bottomup: |
1da177e4 LT |
1407 | /* |
1408 | * A failed mmap() very likely causes application failure, | |
1409 | * so fall back to the bottom-up function here. This scenario | |
1410 | * can happen with large stack limits and large mmap() | |
1411 | * allocations. | |
1412 | */ | |
1363c3cd WW |
1413 | mm->cached_hole_size = ~0UL; |
1414 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1415 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1416 | /* | |
1417 | * Restore the topdown base: | |
1418 | */ | |
1419 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1420 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1421 | |
1422 | return addr; | |
1423 | } | |
1424 | #endif | |
1425 | ||
1363c3cd | 1426 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1427 | { |
1428 | /* | |
1429 | * Is this a new hole at the highest possible address? | |
1430 | */ | |
1363c3cd WW |
1431 | if (addr > mm->free_area_cache) |
1432 | mm->free_area_cache = addr; | |
1da177e4 LT |
1433 | |
1434 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1435 | if (mm->free_area_cache > mm->mmap_base) |
1436 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1437 | } |
1438 | ||
1439 | unsigned long | |
1440 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1441 | unsigned long pgoff, unsigned long flags) | |
1442 | { | |
06abdfb4 BH |
1443 | unsigned long (*get_area)(struct file *, unsigned long, |
1444 | unsigned long, unsigned long, unsigned long); | |
1445 | ||
1446 | get_area = current->mm->get_unmapped_area; | |
1447 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1448 | get_area = file->f_op->get_unmapped_area; | |
1449 | addr = get_area(file, addr, len, pgoff, flags); | |
1450 | if (IS_ERR_VALUE(addr)) | |
1451 | return addr; | |
1da177e4 | 1452 | |
07ab67c8 LT |
1453 | if (addr > TASK_SIZE - len) |
1454 | return -ENOMEM; | |
1455 | if (addr & ~PAGE_MASK) | |
1456 | return -EINVAL; | |
06abdfb4 | 1457 | |
08e7d9b5 | 1458 | return arch_rebalance_pgtables(addr, len); |
1da177e4 LT |
1459 | } |
1460 | ||
1461 | EXPORT_SYMBOL(get_unmapped_area); | |
1462 | ||
1463 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1464 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1465 | { |
1466 | struct vm_area_struct *vma = NULL; | |
1467 | ||
1468 | if (mm) { | |
1469 | /* Check the cache first. */ | |
1470 | /* (Cache hit rate is typically around 35%.) */ | |
1471 | vma = mm->mmap_cache; | |
1472 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1473 | struct rb_node * rb_node; | |
1474 | ||
1475 | rb_node = mm->mm_rb.rb_node; | |
1476 | vma = NULL; | |
1477 | ||
1478 | while (rb_node) { | |
1479 | struct vm_area_struct * vma_tmp; | |
1480 | ||
1481 | vma_tmp = rb_entry(rb_node, | |
1482 | struct vm_area_struct, vm_rb); | |
1483 | ||
1484 | if (vma_tmp->vm_end > addr) { | |
1485 | vma = vma_tmp; | |
1486 | if (vma_tmp->vm_start <= addr) | |
1487 | break; | |
1488 | rb_node = rb_node->rb_left; | |
1489 | } else | |
1490 | rb_node = rb_node->rb_right; | |
1491 | } | |
1492 | if (vma) | |
1493 | mm->mmap_cache = vma; | |
1494 | } | |
1495 | } | |
1496 | return vma; | |
1497 | } | |
1498 | ||
1499 | EXPORT_SYMBOL(find_vma); | |
1500 | ||
1501 | /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ | |
1502 | struct vm_area_struct * | |
1503 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1504 | struct vm_area_struct **pprev) | |
1505 | { | |
1506 | struct vm_area_struct *vma = NULL, *prev = NULL; | |
48aae425 | 1507 | struct rb_node *rb_node; |
1da177e4 LT |
1508 | if (!mm) |
1509 | goto out; | |
1510 | ||
1511 | /* Guard against addr being lower than the first VMA */ | |
1512 | vma = mm->mmap; | |
1513 | ||
1514 | /* Go through the RB tree quickly. */ | |
1515 | rb_node = mm->mm_rb.rb_node; | |
1516 | ||
1517 | while (rb_node) { | |
1518 | struct vm_area_struct *vma_tmp; | |
1519 | vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1520 | ||
1521 | if (addr < vma_tmp->vm_end) { | |
1522 | rb_node = rb_node->rb_left; | |
1523 | } else { | |
1524 | prev = vma_tmp; | |
1525 | if (!prev->vm_next || (addr < prev->vm_next->vm_end)) | |
1526 | break; | |
1527 | rb_node = rb_node->rb_right; | |
1528 | } | |
1529 | } | |
1530 | ||
1531 | out: | |
1532 | *pprev = prev; | |
1533 | return prev ? prev->vm_next : vma; | |
1534 | } | |
1535 | ||
1536 | /* | |
1537 | * Verify that the stack growth is acceptable and | |
1538 | * update accounting. This is shared with both the | |
1539 | * grow-up and grow-down cases. | |
1540 | */ | |
48aae425 | 1541 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
1542 | { |
1543 | struct mm_struct *mm = vma->vm_mm; | |
1544 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1545 | unsigned long new_start; |
1da177e4 LT |
1546 | |
1547 | /* address space limit tests */ | |
119f657c | 1548 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1549 | return -ENOMEM; |
1550 | ||
1551 | /* Stack limit test */ | |
1552 | if (size > rlim[RLIMIT_STACK].rlim_cur) | |
1553 | return -ENOMEM; | |
1554 | ||
1555 | /* mlock limit tests */ | |
1556 | if (vma->vm_flags & VM_LOCKED) { | |
1557 | unsigned long locked; | |
1558 | unsigned long limit; | |
1559 | locked = mm->locked_vm + grow; | |
1560 | limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; | |
1561 | if (locked > limit && !capable(CAP_IPC_LOCK)) | |
1562 | return -ENOMEM; | |
1563 | } | |
1564 | ||
0d59a01b AL |
1565 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1566 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1567 | vma->vm_end - size; | |
1568 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1569 | return -EFAULT; | |
1570 | ||
1da177e4 LT |
1571 | /* |
1572 | * Overcommit.. This must be the final test, as it will | |
1573 | * update security statistics. | |
1574 | */ | |
05fa199d | 1575 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
1576 | return -ENOMEM; |
1577 | ||
1578 | /* Ok, everything looks good - let it rip */ | |
1579 | mm->total_vm += grow; | |
1580 | if (vma->vm_flags & VM_LOCKED) | |
1581 | mm->locked_vm += grow; | |
ab50b8ed | 1582 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1583 | return 0; |
1584 | } | |
1585 | ||
46dea3d0 | 1586 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1587 | /* |
46dea3d0 HD |
1588 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1589 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1590 | */ |
9ab88515 | 1591 | #ifndef CONFIG_IA64 |
cb8f488c | 1592 | static |
46dea3d0 HD |
1593 | #endif |
1594 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) | |
1da177e4 LT |
1595 | { |
1596 | int error; | |
1597 | ||
1598 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1599 | return -EFAULT; | |
1600 | ||
1601 | /* | |
1602 | * We must make sure the anon_vma is allocated | |
1603 | * so that the anon_vma locking is not a noop. | |
1604 | */ | |
1605 | if (unlikely(anon_vma_prepare(vma))) | |
1606 | return -ENOMEM; | |
1607 | anon_vma_lock(vma); | |
1608 | ||
1609 | /* | |
1610 | * vma->vm_start/vm_end cannot change under us because the caller | |
1611 | * is required to hold the mmap_sem in read mode. We need the | |
1612 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 1613 | * Also guard against wrapping around to address 0. |
1da177e4 | 1614 | */ |
06b32f3a HD |
1615 | if (address < PAGE_ALIGN(address+4)) |
1616 | address = PAGE_ALIGN(address+4); | |
1617 | else { | |
1618 | anon_vma_unlock(vma); | |
1619 | return -ENOMEM; | |
1620 | } | |
1da177e4 LT |
1621 | error = 0; |
1622 | ||
1623 | /* Somebody else might have raced and expanded it already */ | |
1624 | if (address > vma->vm_end) { | |
1625 | unsigned long size, grow; | |
1626 | ||
1627 | size = address - vma->vm_start; | |
1628 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1629 | ||
1630 | error = acct_stack_growth(vma, size, grow); | |
1631 | if (!error) | |
1632 | vma->vm_end = address; | |
1633 | } | |
1634 | anon_vma_unlock(vma); | |
1635 | return error; | |
1636 | } | |
46dea3d0 HD |
1637 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1638 | ||
1da177e4 LT |
1639 | /* |
1640 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1641 | */ | |
cb8f488c | 1642 | static int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 1643 | unsigned long address) |
1da177e4 LT |
1644 | { |
1645 | int error; | |
1646 | ||
1647 | /* | |
1648 | * We must make sure the anon_vma is allocated | |
1649 | * so that the anon_vma locking is not a noop. | |
1650 | */ | |
1651 | if (unlikely(anon_vma_prepare(vma))) | |
1652 | return -ENOMEM; | |
8869477a EP |
1653 | |
1654 | address &= PAGE_MASK; | |
88c3f7a8 | 1655 | error = security_file_mmap(NULL, 0, 0, 0, address, 1); |
8869477a EP |
1656 | if (error) |
1657 | return error; | |
1658 | ||
1da177e4 LT |
1659 | anon_vma_lock(vma); |
1660 | ||
1661 | /* | |
1662 | * vma->vm_start/vm_end cannot change under us because the caller | |
1663 | * is required to hold the mmap_sem in read mode. We need the | |
1664 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1665 | */ | |
1da177e4 LT |
1666 | |
1667 | /* Somebody else might have raced and expanded it already */ | |
1668 | if (address < vma->vm_start) { | |
1669 | unsigned long size, grow; | |
1670 | ||
1671 | size = vma->vm_end - address; | |
1672 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1673 | ||
1674 | error = acct_stack_growth(vma, size, grow); | |
1675 | if (!error) { | |
1676 | vma->vm_start = address; | |
1677 | vma->vm_pgoff -= grow; | |
1678 | } | |
1679 | } | |
1680 | anon_vma_unlock(vma); | |
1681 | return error; | |
1682 | } | |
1683 | ||
b6a2fea3 OW |
1684 | int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address) |
1685 | { | |
1686 | return expand_downwards(vma, address); | |
1687 | } | |
1688 | ||
1689 | #ifdef CONFIG_STACK_GROWSUP | |
1690 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1691 | { | |
1692 | return expand_upwards(vma, address); | |
1693 | } | |
1694 | ||
1695 | struct vm_area_struct * | |
1696 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1697 | { | |
1698 | struct vm_area_struct *vma, *prev; | |
1699 | ||
1700 | addr &= PAGE_MASK; | |
1701 | vma = find_vma_prev(mm, addr, &prev); | |
1702 | if (vma && (vma->vm_start <= addr)) | |
1703 | return vma; | |
1c127185 | 1704 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 1705 | return NULL; |
ba470de4 RR |
1706 | if (prev->vm_flags & VM_LOCKED) { |
1707 | if (mlock_vma_pages_range(prev, addr, prev->vm_end) < 0) | |
1708 | return NULL; /* vma gone! */ | |
1709 | } | |
b6a2fea3 OW |
1710 | return prev; |
1711 | } | |
1712 | #else | |
1713 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1714 | { | |
1715 | return expand_downwards(vma, address); | |
1716 | } | |
1717 | ||
1da177e4 LT |
1718 | struct vm_area_struct * |
1719 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1720 | { | |
1721 | struct vm_area_struct * vma; | |
1722 | unsigned long start; | |
1723 | ||
1724 | addr &= PAGE_MASK; | |
1725 | vma = find_vma(mm,addr); | |
1726 | if (!vma) | |
1727 | return NULL; | |
1728 | if (vma->vm_start <= addr) | |
1729 | return vma; | |
1730 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1731 | return NULL; | |
1732 | start = vma->vm_start; | |
1733 | if (expand_stack(vma, addr)) | |
1734 | return NULL; | |
ba470de4 RR |
1735 | if (vma->vm_flags & VM_LOCKED) { |
1736 | if (mlock_vma_pages_range(vma, addr, start) < 0) | |
1737 | return NULL; /* vma gone! */ | |
1738 | } | |
1da177e4 LT |
1739 | return vma; |
1740 | } | |
1741 | #endif | |
1742 | ||
1da177e4 | 1743 | /* |
2c0b3814 | 1744 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1745 | * so release them, and do the vma updates. |
2c0b3814 HD |
1746 | * |
1747 | * Called with the mm semaphore held. | |
1da177e4 | 1748 | */ |
2c0b3814 | 1749 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1750 | { |
365e9c87 HD |
1751 | /* Update high watermark before we lower total_vm */ |
1752 | update_hiwater_vm(mm); | |
1da177e4 | 1753 | do { |
2c0b3814 HD |
1754 | long nrpages = vma_pages(vma); |
1755 | ||
1756 | mm->total_vm -= nrpages; | |
2c0b3814 | 1757 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 1758 | vma = remove_vma(vma); |
146425a3 | 1759 | } while (vma); |
1da177e4 LT |
1760 | validate_mm(mm); |
1761 | } | |
1762 | ||
1763 | /* | |
1764 | * Get rid of page table information in the indicated region. | |
1765 | * | |
f10df686 | 1766 | * Called with the mm semaphore held. |
1da177e4 LT |
1767 | */ |
1768 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1769 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1770 | unsigned long start, unsigned long end) | |
1da177e4 | 1771 | { |
e0da382c | 1772 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
1da177e4 LT |
1773 | struct mmu_gather *tlb; |
1774 | unsigned long nr_accounted = 0; | |
1775 | ||
1776 | lru_add_drain(); | |
1777 | tlb = tlb_gather_mmu(mm, 0); | |
365e9c87 | 1778 | update_hiwater_rss(mm); |
508034a3 | 1779 | unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); |
1da177e4 | 1780 | vm_unacct_memory(nr_accounted); |
42b77728 | 1781 | free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, |
e0da382c | 1782 | next? next->vm_start: 0); |
1da177e4 LT |
1783 | tlb_finish_mmu(tlb, start, end); |
1784 | } | |
1785 | ||
1786 | /* | |
1787 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1788 | * vma list as we go.. | |
1789 | */ | |
1790 | static void | |
1791 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1792 | struct vm_area_struct *prev, unsigned long end) | |
1793 | { | |
1794 | struct vm_area_struct **insertion_point; | |
1795 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1796 | unsigned long addr; |
1da177e4 LT |
1797 | |
1798 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
1799 | do { | |
1800 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1801 | mm->map_count--; | |
1802 | tail_vma = vma; | |
1803 | vma = vma->vm_next; | |
1804 | } while (vma && vma->vm_start < end); | |
1805 | *insertion_point = vma; | |
1806 | tail_vma->vm_next = NULL; | |
1363c3cd WW |
1807 | if (mm->unmap_area == arch_unmap_area) |
1808 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1809 | else | |
1810 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1811 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1812 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1813 | } | |
1814 | ||
1815 | /* | |
1816 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
59c51591 | 1817 | * either for the first part or the tail. |
1da177e4 LT |
1818 | */ |
1819 | int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, | |
1820 | unsigned long addr, int new_below) | |
1821 | { | |
1822 | struct mempolicy *pol; | |
1823 | struct vm_area_struct *new; | |
1824 | ||
a5516438 AK |
1825 | if (is_vm_hugetlb_page(vma) && (addr & |
1826 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
1827 | return -EINVAL; |
1828 | ||
1829 | if (mm->map_count >= sysctl_max_map_count) | |
1830 | return -ENOMEM; | |
1831 | ||
e94b1766 | 1832 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1833 | if (!new) |
1834 | return -ENOMEM; | |
1835 | ||
1836 | /* most fields are the same, copy all, and then fixup */ | |
1837 | *new = *vma; | |
1838 | ||
1839 | if (new_below) | |
1840 | new->vm_end = addr; | |
1841 | else { | |
1842 | new->vm_start = addr; | |
1843 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
1844 | } | |
1845 | ||
846a16bf | 1846 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 LT |
1847 | if (IS_ERR(pol)) { |
1848 | kmem_cache_free(vm_area_cachep, new); | |
1849 | return PTR_ERR(pol); | |
1850 | } | |
1851 | vma_set_policy(new, pol); | |
1852 | ||
925d1c40 | 1853 | if (new->vm_file) { |
1da177e4 | 1854 | get_file(new->vm_file); |
925d1c40 MH |
1855 | if (vma->vm_flags & VM_EXECUTABLE) |
1856 | added_exe_file_vma(mm); | |
1857 | } | |
1da177e4 LT |
1858 | |
1859 | if (new->vm_ops && new->vm_ops->open) | |
1860 | new->vm_ops->open(new); | |
1861 | ||
1862 | if (new_below) | |
1863 | vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + | |
1864 | ((addr - new->vm_start) >> PAGE_SHIFT), new); | |
1865 | else | |
1866 | vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); | |
1867 | ||
1868 | return 0; | |
1869 | } | |
1870 | ||
1871 | /* Munmap is split into 2 main parts -- this part which finds | |
1872 | * what needs doing, and the areas themselves, which do the | |
1873 | * work. This now handles partial unmappings. | |
1874 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
1875 | */ | |
1876 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
1877 | { | |
1878 | unsigned long end; | |
146425a3 | 1879 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
1880 | |
1881 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
1882 | return -EINVAL; | |
1883 | ||
1884 | if ((len = PAGE_ALIGN(len)) == 0) | |
1885 | return -EINVAL; | |
1886 | ||
1887 | /* Find the first overlapping VMA */ | |
146425a3 HD |
1888 | vma = find_vma_prev(mm, start, &prev); |
1889 | if (!vma) | |
1da177e4 | 1890 | return 0; |
146425a3 | 1891 | /* we have start < vma->vm_end */ |
1da177e4 LT |
1892 | |
1893 | /* if it doesn't overlap, we have nothing.. */ | |
1894 | end = start + len; | |
146425a3 | 1895 | if (vma->vm_start >= end) |
1da177e4 LT |
1896 | return 0; |
1897 | ||
1898 | /* | |
1899 | * If we need to split any vma, do it now to save pain later. | |
1900 | * | |
1901 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
1902 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
1903 | * places tmp vma above, and higher split_vma places tmp vma below. | |
1904 | */ | |
146425a3 HD |
1905 | if (start > vma->vm_start) { |
1906 | int error = split_vma(mm, vma, start, 0); | |
1da177e4 LT |
1907 | if (error) |
1908 | return error; | |
146425a3 | 1909 | prev = vma; |
1da177e4 LT |
1910 | } |
1911 | ||
1912 | /* Does it split the last one? */ | |
1913 | last = find_vma(mm, end); | |
1914 | if (last && end > last->vm_start) { | |
1915 | int error = split_vma(mm, last, end, 1); | |
1916 | if (error) | |
1917 | return error; | |
1918 | } | |
146425a3 | 1919 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 1920 | |
ba470de4 RR |
1921 | /* |
1922 | * unlock any mlock()ed ranges before detaching vmas | |
1923 | */ | |
1924 | if (mm->locked_vm) { | |
1925 | struct vm_area_struct *tmp = vma; | |
1926 | while (tmp && tmp->vm_start < end) { | |
1927 | if (tmp->vm_flags & VM_LOCKED) { | |
1928 | mm->locked_vm -= vma_pages(tmp); | |
1929 | munlock_vma_pages_all(tmp); | |
1930 | } | |
1931 | tmp = tmp->vm_next; | |
1932 | } | |
1933 | } | |
1934 | ||
1da177e4 LT |
1935 | /* |
1936 | * Remove the vma's, and unmap the actual pages | |
1937 | */ | |
146425a3 HD |
1938 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
1939 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
1940 | |
1941 | /* Fix up all other VM information */ | |
2c0b3814 | 1942 | remove_vma_list(mm, vma); |
1da177e4 LT |
1943 | |
1944 | return 0; | |
1945 | } | |
1946 | ||
1947 | EXPORT_SYMBOL(do_munmap); | |
1948 | ||
6a6160a7 | 1949 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
1da177e4 LT |
1950 | { |
1951 | int ret; | |
1952 | struct mm_struct *mm = current->mm; | |
1953 | ||
1954 | profile_munmap(addr); | |
1955 | ||
1956 | down_write(&mm->mmap_sem); | |
1957 | ret = do_munmap(mm, addr, len); | |
1958 | up_write(&mm->mmap_sem); | |
1959 | return ret; | |
1960 | } | |
1961 | ||
1962 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
1963 | { | |
a241ec65 | 1964 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
1965 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
1966 | WARN_ON(1); | |
1967 | up_read(&mm->mmap_sem); | |
1968 | } | |
1969 | #endif | |
1970 | } | |
1971 | ||
1972 | /* | |
1973 | * this is really a simplified "do_mmap". it only handles | |
1974 | * anonymous maps. eventually we may be able to do some | |
1975 | * brk-specific accounting here. | |
1976 | */ | |
1977 | unsigned long do_brk(unsigned long addr, unsigned long len) | |
1978 | { | |
1979 | struct mm_struct * mm = current->mm; | |
1980 | struct vm_area_struct * vma, * prev; | |
1981 | unsigned long flags; | |
1982 | struct rb_node ** rb_link, * rb_parent; | |
1983 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 1984 | int error; |
1da177e4 LT |
1985 | |
1986 | len = PAGE_ALIGN(len); | |
1987 | if (!len) | |
1988 | return addr; | |
1989 | ||
1990 | if ((addr + len) > TASK_SIZE || (addr + len) < addr) | |
1991 | return -EINVAL; | |
1992 | ||
cd2579d7 HD |
1993 | if (is_hugepage_only_range(mm, addr, len)) |
1994 | return -EINVAL; | |
cb07c9a1 | 1995 | |
88c3f7a8 | 1996 | error = security_file_mmap(NULL, 0, 0, 0, addr, 1); |
5a211a5d EP |
1997 | if (error) |
1998 | return error; | |
1999 | ||
3a459756 KK |
2000 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2001 | ||
2002 | error = arch_mmap_check(addr, len, flags); | |
2003 | if (error) | |
2004 | return error; | |
2005 | ||
1da177e4 LT |
2006 | /* |
2007 | * mlock MCL_FUTURE? | |
2008 | */ | |
2009 | if (mm->def_flags & VM_LOCKED) { | |
2010 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
2011 | locked = len >> PAGE_SHIFT; |
2012 | locked += mm->locked_vm; | |
1da177e4 | 2013 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 2014 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
2015 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
2016 | return -EAGAIN; | |
2017 | } | |
2018 | ||
2019 | /* | |
2020 | * mm->mmap_sem is required to protect against another thread | |
2021 | * changing the mappings in case we sleep. | |
2022 | */ | |
2023 | verify_mm_writelocked(mm); | |
2024 | ||
2025 | /* | |
2026 | * Clear old maps. this also does some error checking for us | |
2027 | */ | |
2028 | munmap_back: | |
2029 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2030 | if (vma && vma->vm_start < addr + len) { | |
2031 | if (do_munmap(mm, addr, len)) | |
2032 | return -ENOMEM; | |
2033 | goto munmap_back; | |
2034 | } | |
2035 | ||
2036 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2037 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2038 | return -ENOMEM; |
2039 | ||
2040 | if (mm->map_count > sysctl_max_map_count) | |
2041 | return -ENOMEM; | |
2042 | ||
2043 | if (security_vm_enough_memory(len >> PAGE_SHIFT)) | |
2044 | return -ENOMEM; | |
2045 | ||
1da177e4 | 2046 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2047 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2048 | NULL, NULL, pgoff, NULL); | |
2049 | if (vma) | |
1da177e4 LT |
2050 | goto out; |
2051 | ||
2052 | /* | |
2053 | * create a vma struct for an anonymous mapping | |
2054 | */ | |
c5e3b83e | 2055 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2056 | if (!vma) { |
2057 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2058 | return -ENOMEM; | |
2059 | } | |
1da177e4 LT |
2060 | |
2061 | vma->vm_mm = mm; | |
2062 | vma->vm_start = addr; | |
2063 | vma->vm_end = addr + len; | |
2064 | vma->vm_pgoff = pgoff; | |
2065 | vma->vm_flags = flags; | |
3ed75eb8 | 2066 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2067 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2068 | out: | |
2069 | mm->total_vm += len >> PAGE_SHIFT; | |
2070 | if (flags & VM_LOCKED) { | |
ba470de4 RR |
2071 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
2072 | mm->locked_vm += (len >> PAGE_SHIFT); | |
1da177e4 LT |
2073 | } |
2074 | return addr; | |
2075 | } | |
2076 | ||
2077 | EXPORT_SYMBOL(do_brk); | |
2078 | ||
2079 | /* Release all mmaps. */ | |
2080 | void exit_mmap(struct mm_struct *mm) | |
2081 | { | |
2082 | struct mmu_gather *tlb; | |
ba470de4 | 2083 | struct vm_area_struct *vma; |
1da177e4 | 2084 | unsigned long nr_accounted = 0; |
ee39b37b | 2085 | unsigned long end; |
1da177e4 | 2086 | |
d6dd61c8 | 2087 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2088 | mmu_notifier_release(mm); |
d6dd61c8 | 2089 | |
ba470de4 RR |
2090 | if (mm->locked_vm) { |
2091 | vma = mm->mmap; | |
2092 | while (vma) { | |
2093 | if (vma->vm_flags & VM_LOCKED) | |
2094 | munlock_vma_pages_all(vma); | |
2095 | vma = vma->vm_next; | |
2096 | } | |
2097 | } | |
9480c53e JF |
2098 | |
2099 | arch_exit_mmap(mm); | |
2100 | ||
ba470de4 | 2101 | vma = mm->mmap; |
9480c53e JF |
2102 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2103 | return; | |
2104 | ||
1da177e4 | 2105 | lru_add_drain(); |
1da177e4 | 2106 | flush_cache_mm(mm); |
e0da382c | 2107 | tlb = tlb_gather_mmu(mm, 1); |
901608d9 | 2108 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2109 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
508034a3 | 2110 | end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); |
1da177e4 | 2111 | vm_unacct_memory(nr_accounted); |
9ba69294 | 2112 | |
42b77728 | 2113 | free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0); |
ee39b37b | 2114 | tlb_finish_mmu(tlb, 0, end); |
1da177e4 | 2115 | |
1da177e4 | 2116 | /* |
8f4f8c16 HD |
2117 | * Walk the list again, actually closing and freeing it, |
2118 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2119 | */ |
a8fb5618 HD |
2120 | while (vma) |
2121 | vma = remove_vma(vma); | |
e0da382c | 2122 | |
e2cdef8c | 2123 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
2124 | } |
2125 | ||
2126 | /* Insert vm structure into process list sorted by address | |
2127 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
2128 | * then i_mmap_lock is taken here. | |
2129 | */ | |
2130 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
2131 | { | |
2132 | struct vm_area_struct * __vma, * prev; | |
2133 | struct rb_node ** rb_link, * rb_parent; | |
2134 | ||
2135 | /* | |
2136 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2137 | * until its first write fault, when page's anon_vma and index | |
2138 | * are set. But now set the vm_pgoff it will almost certainly | |
2139 | * end up with (unless mremap moves it elsewhere before that | |
2140 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2141 | * | |
2142 | * By setting it to reflect the virtual start address of the | |
2143 | * vma, merges and splits can happen in a seamless way, just | |
2144 | * using the existing file pgoff checks and manipulations. | |
2145 | * Similarly in do_mmap_pgoff and in do_brk. | |
2146 | */ | |
2147 | if (!vma->vm_file) { | |
2148 | BUG_ON(vma->anon_vma); | |
2149 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2150 | } | |
2151 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); | |
2152 | if (__vma && __vma->vm_start < vma->vm_end) | |
2153 | return -ENOMEM; | |
2fd4ef85 | 2154 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2155 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2156 | return -ENOMEM; |
1da177e4 LT |
2157 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2158 | return 0; | |
2159 | } | |
2160 | ||
2161 | /* | |
2162 | * Copy the vma structure to a new location in the same mm, | |
2163 | * prior to moving page table entries, to effect an mremap move. | |
2164 | */ | |
2165 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
2166 | unsigned long addr, unsigned long len, pgoff_t pgoff) | |
2167 | { | |
2168 | struct vm_area_struct *vma = *vmap; | |
2169 | unsigned long vma_start = vma->vm_start; | |
2170 | struct mm_struct *mm = vma->vm_mm; | |
2171 | struct vm_area_struct *new_vma, *prev; | |
2172 | struct rb_node **rb_link, *rb_parent; | |
2173 | struct mempolicy *pol; | |
2174 | ||
2175 | /* | |
2176 | * If anonymous vma has not yet been faulted, update new pgoff | |
2177 | * to match new location, to increase its chance of merging. | |
2178 | */ | |
2179 | if (!vma->vm_file && !vma->anon_vma) | |
2180 | pgoff = addr >> PAGE_SHIFT; | |
2181 | ||
2182 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2183 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, | |
2184 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2185 | if (new_vma) { | |
2186 | /* | |
2187 | * Source vma may have been merged into new_vma | |
2188 | */ | |
2189 | if (vma_start >= new_vma->vm_start && | |
2190 | vma_start < new_vma->vm_end) | |
2191 | *vmap = new_vma; | |
2192 | } else { | |
e94b1766 | 2193 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2194 | if (new_vma) { |
2195 | *new_vma = *vma; | |
846a16bf | 2196 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 LT |
2197 | if (IS_ERR(pol)) { |
2198 | kmem_cache_free(vm_area_cachep, new_vma); | |
2199 | return NULL; | |
2200 | } | |
2201 | vma_set_policy(new_vma, pol); | |
2202 | new_vma->vm_start = addr; | |
2203 | new_vma->vm_end = addr + len; | |
2204 | new_vma->vm_pgoff = pgoff; | |
925d1c40 | 2205 | if (new_vma->vm_file) { |
1da177e4 | 2206 | get_file(new_vma->vm_file); |
925d1c40 MH |
2207 | if (vma->vm_flags & VM_EXECUTABLE) |
2208 | added_exe_file_vma(mm); | |
2209 | } | |
1da177e4 LT |
2210 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
2211 | new_vma->vm_ops->open(new_vma); | |
2212 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
2213 | } | |
2214 | } | |
2215 | return new_vma; | |
2216 | } | |
119f657c | 2217 | |
2218 | /* | |
2219 | * Return true if the calling process may expand its vm space by the passed | |
2220 | * number of pages | |
2221 | */ | |
2222 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2223 | { | |
2224 | unsigned long cur = mm->total_vm; /* pages */ | |
2225 | unsigned long lim; | |
2226 | ||
2227 | lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; | |
2228 | ||
2229 | if (cur + npages > lim) | |
2230 | return 0; | |
2231 | return 1; | |
2232 | } | |
fa5dc22f RM |
2233 | |
2234 | ||
b1d0e4f5 NP |
2235 | static int special_mapping_fault(struct vm_area_struct *vma, |
2236 | struct vm_fault *vmf) | |
fa5dc22f | 2237 | { |
b1d0e4f5 | 2238 | pgoff_t pgoff; |
fa5dc22f RM |
2239 | struct page **pages; |
2240 | ||
b1d0e4f5 NP |
2241 | /* |
2242 | * special mappings have no vm_file, and in that case, the mm | |
2243 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2244 | * We are allowed to do this because we are the mm; do not copy | |
2245 | * this code into drivers! | |
2246 | */ | |
2247 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2248 | |
b1d0e4f5 NP |
2249 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2250 | pgoff--; | |
fa5dc22f RM |
2251 | |
2252 | if (*pages) { | |
2253 | struct page *page = *pages; | |
2254 | get_page(page); | |
b1d0e4f5 NP |
2255 | vmf->page = page; |
2256 | return 0; | |
fa5dc22f RM |
2257 | } |
2258 | ||
b1d0e4f5 | 2259 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2260 | } |
2261 | ||
2262 | /* | |
2263 | * Having a close hook prevents vma merging regardless of flags. | |
2264 | */ | |
2265 | static void special_mapping_close(struct vm_area_struct *vma) | |
2266 | { | |
2267 | } | |
2268 | ||
2269 | static struct vm_operations_struct special_mapping_vmops = { | |
2270 | .close = special_mapping_close, | |
b1d0e4f5 | 2271 | .fault = special_mapping_fault, |
fa5dc22f RM |
2272 | }; |
2273 | ||
2274 | /* | |
2275 | * Called with mm->mmap_sem held for writing. | |
2276 | * Insert a new vma covering the given region, with the given flags. | |
2277 | * Its pages are supplied by the given array of struct page *. | |
2278 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2279 | * The region past the last page supplied will always produce SIGBUS. | |
2280 | * The array pointer and the pages it points to are assumed to stay alive | |
2281 | * for as long as this mapping might exist. | |
2282 | */ | |
2283 | int install_special_mapping(struct mm_struct *mm, | |
2284 | unsigned long addr, unsigned long len, | |
2285 | unsigned long vm_flags, struct page **pages) | |
2286 | { | |
2287 | struct vm_area_struct *vma; | |
2288 | ||
2289 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2290 | if (unlikely(vma == NULL)) | |
2291 | return -ENOMEM; | |
2292 | ||
2293 | vma->vm_mm = mm; | |
2294 | vma->vm_start = addr; | |
2295 | vma->vm_end = addr + len; | |
2296 | ||
2f98735c | 2297 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
3ed75eb8 | 2298 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2299 | |
2300 | vma->vm_ops = &special_mapping_vmops; | |
2301 | vma->vm_private_data = pages; | |
2302 | ||
2303 | if (unlikely(insert_vm_struct(mm, vma))) { | |
2304 | kmem_cache_free(vm_area_cachep, vma); | |
2305 | return -ENOMEM; | |
2306 | } | |
2307 | ||
2308 | mm->total_vm += len >> PAGE_SHIFT; | |
2309 | ||
cdd6c482 | 2310 | perf_event_mmap(vma); |
089dd79d | 2311 | |
fa5dc22f RM |
2312 | return 0; |
2313 | } | |
7906d00c AA |
2314 | |
2315 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
2316 | ||
454ed842 | 2317 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c AA |
2318 | { |
2319 | if (!test_bit(0, (unsigned long *) &anon_vma->head.next)) { | |
2320 | /* | |
2321 | * The LSB of head.next can't change from under us | |
2322 | * because we hold the mm_all_locks_mutex. | |
2323 | */ | |
454ed842 | 2324 | spin_lock_nest_lock(&anon_vma->lock, &mm->mmap_sem); |
7906d00c AA |
2325 | /* |
2326 | * We can safely modify head.next after taking the | |
2327 | * anon_vma->lock. If some other vma in this mm shares | |
2328 | * the same anon_vma we won't take it again. | |
2329 | * | |
2330 | * No need of atomic instructions here, head.next | |
2331 | * can't change from under us thanks to the | |
2332 | * anon_vma->lock. | |
2333 | */ | |
2334 | if (__test_and_set_bit(0, (unsigned long *) | |
2335 | &anon_vma->head.next)) | |
2336 | BUG(); | |
2337 | } | |
2338 | } | |
2339 | ||
454ed842 | 2340 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
2341 | { |
2342 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2343 | /* | |
2344 | * AS_MM_ALL_LOCKS can't change from under us because | |
2345 | * we hold the mm_all_locks_mutex. | |
2346 | * | |
2347 | * Operations on ->flags have to be atomic because | |
2348 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
2349 | * mm_all_locks_mutex, there may be other cpus | |
2350 | * changing other bitflags in parallel to us. | |
2351 | */ | |
2352 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
2353 | BUG(); | |
454ed842 | 2354 | spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem); |
7906d00c AA |
2355 | } |
2356 | } | |
2357 | ||
2358 | /* | |
2359 | * This operation locks against the VM for all pte/vma/mm related | |
2360 | * operations that could ever happen on a certain mm. This includes | |
2361 | * vmtruncate, try_to_unmap, and all page faults. | |
2362 | * | |
2363 | * The caller must take the mmap_sem in write mode before calling | |
2364 | * mm_take_all_locks(). The caller isn't allowed to release the | |
2365 | * mmap_sem until mm_drop_all_locks() returns. | |
2366 | * | |
2367 | * mmap_sem in write mode is required in order to block all operations | |
2368 | * that could modify pagetables and free pages without need of | |
2369 | * altering the vma layout (for example populate_range() with | |
2370 | * nonlinear vmas). It's also needed in write mode to avoid new | |
2371 | * anon_vmas to be associated with existing vmas. | |
2372 | * | |
2373 | * A single task can't take more than one mm_take_all_locks() in a row | |
2374 | * or it would deadlock. | |
2375 | * | |
2376 | * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in | |
2377 | * mapping->flags avoid to take the same lock twice, if more than one | |
2378 | * vma in this mm is backed by the same anon_vma or address_space. | |
2379 | * | |
2380 | * We can take all the locks in random order because the VM code | |
2381 | * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never | |
2382 | * takes more than one of them in a row. Secondly we're protected | |
2383 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
2384 | * | |
2385 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
2386 | * that may have to take thousand of locks. | |
2387 | * | |
2388 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
2389 | */ | |
2390 | int mm_take_all_locks(struct mm_struct *mm) | |
2391 | { | |
2392 | struct vm_area_struct *vma; | |
2393 | int ret = -EINTR; | |
2394 | ||
2395 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2396 | ||
2397 | mutex_lock(&mm_all_locks_mutex); | |
2398 | ||
2399 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2400 | if (signal_pending(current)) | |
2401 | goto out_unlock; | |
7906d00c | 2402 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 2403 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 2404 | } |
7cd5a02f PZ |
2405 | |
2406 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2407 | if (signal_pending(current)) | |
2408 | goto out_unlock; | |
2409 | if (vma->anon_vma) | |
2410 | vm_lock_anon_vma(mm, vma->anon_vma); | |
7906d00c | 2411 | } |
7cd5a02f | 2412 | |
7906d00c AA |
2413 | ret = 0; |
2414 | ||
2415 | out_unlock: | |
2416 | if (ret) | |
2417 | mm_drop_all_locks(mm); | |
2418 | ||
2419 | return ret; | |
2420 | } | |
2421 | ||
2422 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
2423 | { | |
2424 | if (test_bit(0, (unsigned long *) &anon_vma->head.next)) { | |
2425 | /* | |
2426 | * The LSB of head.next can't change to 0 from under | |
2427 | * us because we hold the mm_all_locks_mutex. | |
2428 | * | |
2429 | * We must however clear the bitflag before unlocking | |
2430 | * the vma so the users using the anon_vma->head will | |
2431 | * never see our bitflag. | |
2432 | * | |
2433 | * No need of atomic instructions here, head.next | |
2434 | * can't change from under us until we release the | |
2435 | * anon_vma->lock. | |
2436 | */ | |
2437 | if (!__test_and_clear_bit(0, (unsigned long *) | |
2438 | &anon_vma->head.next)) | |
2439 | BUG(); | |
2440 | spin_unlock(&anon_vma->lock); | |
2441 | } | |
2442 | } | |
2443 | ||
2444 | static void vm_unlock_mapping(struct address_space *mapping) | |
2445 | { | |
2446 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2447 | /* | |
2448 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
2449 | * because we hold the mm_all_locks_mutex. | |
2450 | */ | |
2451 | spin_unlock(&mapping->i_mmap_lock); | |
2452 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, | |
2453 | &mapping->flags)) | |
2454 | BUG(); | |
2455 | } | |
2456 | } | |
2457 | ||
2458 | /* | |
2459 | * The mmap_sem cannot be released by the caller until | |
2460 | * mm_drop_all_locks() returns. | |
2461 | */ | |
2462 | void mm_drop_all_locks(struct mm_struct *mm) | |
2463 | { | |
2464 | struct vm_area_struct *vma; | |
2465 | ||
2466 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2467 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
2468 | ||
2469 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2470 | if (vma->anon_vma) | |
2471 | vm_unlock_anon_vma(vma->anon_vma); | |
2472 | if (vma->vm_file && vma->vm_file->f_mapping) | |
2473 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
2474 | } | |
2475 | ||
2476 | mutex_unlock(&mm_all_locks_mutex); | |
2477 | } | |
8feae131 DH |
2478 | |
2479 | /* | |
2480 | * initialise the VMA slab | |
2481 | */ | |
2482 | void __init mmap_init(void) | |
2483 | { | |
00a62ce9 KM |
2484 | int ret; |
2485 | ||
2486 | ret = percpu_counter_init(&vm_committed_as, 0); | |
2487 | VM_BUG_ON(ret); | |
8feae131 | 2488 | } |