Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/mm/mmap.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 54084 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * mm/mmap.c |
3 | * |
4 | * Written by obz. |
5 | * |
6 | * Address space accounting code <alan@redhat.com> |
7 | */ |
8 | |
9 | #include <linux/slab.h> |
10 | #include <linux/mm.h> |
11 | #include <linux/shm.h> |
12 | #include <linux/mman.h> |
13 | #include <linux/pagemap.h> |
14 | #include <linux/swap.h> |
15 | #include <linux/syscalls.h> |
16 | #include <linux/init.h> |
17 | #include <linux/file.h> |
18 | #include <linux/fs.h> |
19 | #include <linux/personality.h> |
20 | #include <linux/security.h> |
21 | #include <linux/hugetlb.h> |
22 | #include <linux/profile.h> |
23 | #include <linux/module.h> |
24 | #include <linux/mount.h> |
25 | #include <linux/mempolicy.h> |
26 | #include <linux/rmap.h> |
27 | |
28 | #include <asm/uaccess.h> |
29 | #include <asm/cacheflush.h> |
30 | #include <asm/tlb.h> |
31 | |
32 | static void unmap_region(struct mm_struct *mm, |
33 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
34 | unsigned long start, unsigned long end); |
35 | |
36 | /* |
37 | * WARNING: the debugging will use recursive algorithms so never enable this |
38 | * unless you know what you are doing. |
39 | */ |
40 | #undef DEBUG_MM_RB |
41 | |
42 | /* description of effects of mapping type and prot in current implementation. |
43 | * this is due to the limited x86 page protection hardware. The expected |
44 | * behavior is in parens: |
45 | * |
46 | * map_type prot |
47 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC |
48 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
49 | * w: (no) no w: (no) no w: (yes) yes w: (no) no |
50 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
51 | * |
52 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
53 | * w: (no) no w: (no) no w: (copy) copy w: (no) no |
54 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
55 | * |
56 | */ |
57 | pgprot_t protection_map[16] = { |
58 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, |
59 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 |
60 | }; |
61 | |
62 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
63 | int sysctl_overcommit_ratio = 50; /* default is 50% */ |
64 | int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; |
65 | atomic_t vm_committed_space = ATOMIC_INIT(0); |
66 | |
67 | /* |
68 | * Check that a process has enough memory to allocate a new virtual |
69 | * mapping. 0 means there is enough memory for the allocation to |
70 | * succeed and -ENOMEM implies there is not. |
71 | * |
72 | * We currently support three overcommit policies, which are set via the |
73 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
74 | * |
75 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
76 | * Additional code 2002 Jul 20 by Robert Love. |
77 | * |
78 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
79 | * |
80 | * Note this is a helper function intended to be used by LSMs which |
81 | * wish to use this logic. |
82 | */ |
83 | int __vm_enough_memory(long pages, int cap_sys_admin) |
84 | { |
85 | unsigned long free, allowed; |
86 | |
87 | vm_acct_memory(pages); |
88 | |
89 | /* |
90 | * Sometimes we want to use more memory than we have |
91 | */ |
92 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
93 | return 0; |
94 | |
95 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
96 | unsigned long n; |
97 | |
98 | free = get_page_cache_size(); |
99 | free += nr_swap_pages; |
100 | |
101 | /* |
102 | * Any slabs which are created with the |
103 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
104 | * which are reclaimable, under pressure. The dentry |
105 | * cache and most inode caches should fall into this |
106 | */ |
107 | free += atomic_read(&slab_reclaim_pages); |
108 | |
109 | /* |
110 | * Leave the last 3% for root |
111 | */ |
112 | if (!cap_sys_admin) |
113 | free -= free / 32; |
114 | |
115 | if (free > pages) |
116 | return 0; |
117 | |
118 | /* |
119 | * nr_free_pages() is very expensive on large systems, |
120 | * only call if we're about to fail. |
121 | */ |
122 | n = nr_free_pages(); |
123 | if (!cap_sys_admin) |
124 | n -= n / 32; |
125 | free += n; |
126 | |
127 | if (free > pages) |
128 | return 0; |
129 | vm_unacct_memory(pages); |
130 | return -ENOMEM; |
131 | } |
132 | |
133 | allowed = (totalram_pages - hugetlb_total_pages()) |
134 | * sysctl_overcommit_ratio / 100; |
135 | /* |
136 | * Leave the last 3% for root |
137 | */ |
138 | if (!cap_sys_admin) |
139 | allowed -= allowed / 32; |
140 | allowed += total_swap_pages; |
141 | |
142 | /* Don't let a single process grow too big: |
143 | leave 3% of the size of this process for other processes */ |
144 | allowed -= current->mm->total_vm / 32; |
145 | |
146 | if (atomic_read(&vm_committed_space) < allowed) |
147 | return 0; |
148 | |
149 | vm_unacct_memory(pages); |
150 | |
151 | return -ENOMEM; |
152 | } |
153 | |
154 | EXPORT_SYMBOL(sysctl_overcommit_memory); |
155 | EXPORT_SYMBOL(sysctl_overcommit_ratio); |
156 | EXPORT_SYMBOL(sysctl_max_map_count); |
157 | EXPORT_SYMBOL(vm_committed_space); |
158 | EXPORT_SYMBOL(__vm_enough_memory); |
159 | |
160 | /* |
161 | * Requires inode->i_mapping->i_mmap_lock |
162 | */ |
163 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, |
164 | struct file *file, struct address_space *mapping) |
165 | { |
166 | if (vma->vm_flags & VM_DENYWRITE) |
167 | atomic_inc(&file->f_dentry->d_inode->i_writecount); |
168 | if (vma->vm_flags & VM_SHARED) |
169 | mapping->i_mmap_writable--; |
170 | |
171 | flush_dcache_mmap_lock(mapping); |
172 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
173 | list_del_init(&vma->shared.vm_set.list); |
174 | else |
175 | vma_prio_tree_remove(vma, &mapping->i_mmap); |
176 | flush_dcache_mmap_unlock(mapping); |
177 | } |
178 | |
179 | /* |
180 | * Remove one vm structure and free it. |
181 | */ |
182 | static void remove_vm_struct(struct vm_area_struct *vma) |
183 | { |
184 | struct file *file = vma->vm_file; |
185 | |
186 | might_sleep(); |
187 | if (file) { |
188 | struct address_space *mapping = file->f_mapping; |
189 | spin_lock(&mapping->i_mmap_lock); |
190 | __remove_shared_vm_struct(vma, file, mapping); |
191 | spin_unlock(&mapping->i_mmap_lock); |
192 | } |
193 | if (vma->vm_ops && vma->vm_ops->close) |
194 | vma->vm_ops->close(vma); |
195 | if (file) |
196 | fput(file); |
197 | anon_vma_unlink(vma); |
198 | mpol_free(vma_policy(vma)); |
199 | kmem_cache_free(vm_area_cachep, vma); |
200 | } |
201 | |
202 | /* |
203 | * sys_brk() for the most part doesn't need the global kernel |
204 | * lock, except when an application is doing something nasty |
205 | * like trying to un-brk an area that has already been mapped |
206 | * to a regular file. in this case, the unmapping will need |
207 | * to invoke file system routines that need the global lock. |
208 | */ |
209 | asmlinkage unsigned long sys_brk(unsigned long brk) |
210 | { |
211 | unsigned long rlim, retval; |
212 | unsigned long newbrk, oldbrk; |
213 | struct mm_struct *mm = current->mm; |
214 | |
215 | down_write(&mm->mmap_sem); |
216 | |
217 | if (brk < mm->end_code) |
218 | goto out; |
219 | newbrk = PAGE_ALIGN(brk); |
220 | oldbrk = PAGE_ALIGN(mm->brk); |
221 | if (oldbrk == newbrk) |
222 | goto set_brk; |
223 | |
224 | /* Always allow shrinking brk. */ |
225 | if (brk <= mm->brk) { |
226 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) |
227 | goto set_brk; |
228 | goto out; |
229 | } |
230 | |
231 | /* Check against rlimit.. */ |
232 | rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; |
233 | if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) |
234 | goto out; |
235 | |
236 | /* Check against existing mmap mappings. */ |
237 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) |
238 | goto out; |
239 | |
240 | /* Ok, looks good - let it rip. */ |
241 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) |
242 | goto out; |
243 | set_brk: |
244 | mm->brk = brk; |
245 | out: |
246 | retval = mm->brk; |
247 | up_write(&mm->mmap_sem); |
248 | return retval; |
249 | } |
250 | |
251 | #ifdef DEBUG_MM_RB |
252 | static int browse_rb(struct rb_root *root) |
253 | { |
254 | int i = 0, j; |
255 | struct rb_node *nd, *pn = NULL; |
256 | unsigned long prev = 0, pend = 0; |
257 | |
258 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { |
259 | struct vm_area_struct *vma; |
260 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); |
261 | if (vma->vm_start < prev) |
262 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; |
263 | if (vma->vm_start < pend) |
264 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); |
265 | if (vma->vm_start > vma->vm_end) |
266 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); |
267 | i++; |
268 | pn = nd; |
269 | } |
270 | j = 0; |
271 | for (nd = pn; nd; nd = rb_prev(nd)) { |
272 | j++; |
273 | } |
274 | if (i != j) |
275 | printk("backwards %d, forwards %d\n", j, i), i = 0; |
276 | return i; |
277 | } |
278 | |
279 | void validate_mm(struct mm_struct *mm) |
280 | { |
281 | int bug = 0; |
282 | int i = 0; |
283 | struct vm_area_struct *tmp = mm->mmap; |
284 | while (tmp) { |
285 | tmp = tmp->vm_next; |
286 | i++; |
287 | } |
288 | if (i != mm->map_count) |
289 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; |
290 | i = browse_rb(&mm->mm_rb); |
291 | if (i != mm->map_count) |
292 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; |
293 | if (bug) |
294 | BUG(); |
295 | } |
296 | #else |
297 | #define validate_mm(mm) do { } while (0) |
298 | #endif |
299 | |
300 | static struct vm_area_struct * |
301 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, |
302 | struct vm_area_struct **pprev, struct rb_node ***rb_link, |
303 | struct rb_node ** rb_parent) |
304 | { |
305 | struct vm_area_struct * vma; |
306 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; |
307 | |
308 | __rb_link = &mm->mm_rb.rb_node; |
309 | rb_prev = __rb_parent = NULL; |
310 | vma = NULL; |
311 | |
312 | while (*__rb_link) { |
313 | struct vm_area_struct *vma_tmp; |
314 | |
315 | __rb_parent = *__rb_link; |
316 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); |
317 | |
318 | if (vma_tmp->vm_end > addr) { |
319 | vma = vma_tmp; |
320 | if (vma_tmp->vm_start <= addr) |
321 | return vma; |
322 | __rb_link = &__rb_parent->rb_left; |
323 | } else { |
324 | rb_prev = __rb_parent; |
325 | __rb_link = &__rb_parent->rb_right; |
326 | } |
327 | } |
328 | |
329 | *pprev = NULL; |
330 | if (rb_prev) |
331 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
332 | *rb_link = __rb_link; |
333 | *rb_parent = __rb_parent; |
334 | return vma; |
335 | } |
336 | |
337 | static inline void |
338 | __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
339 | struct vm_area_struct *prev, struct rb_node *rb_parent) |
340 | { |
341 | if (prev) { |
342 | vma->vm_next = prev->vm_next; |
343 | prev->vm_next = vma; |
344 | } else { |
345 | mm->mmap = vma; |
346 | if (rb_parent) |
347 | vma->vm_next = rb_entry(rb_parent, |
348 | struct vm_area_struct, vm_rb); |
349 | else |
350 | vma->vm_next = NULL; |
351 | } |
352 | } |
353 | |
354 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
355 | struct rb_node **rb_link, struct rb_node *rb_parent) |
356 | { |
357 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
358 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
359 | } |
360 | |
361 | static inline void __vma_link_file(struct vm_area_struct *vma) |
362 | { |
363 | struct file * file; |
364 | |
365 | file = vma->vm_file; |
366 | if (file) { |
367 | struct address_space *mapping = file->f_mapping; |
368 | |
369 | if (vma->vm_flags & VM_DENYWRITE) |
370 | atomic_dec(&file->f_dentry->d_inode->i_writecount); |
371 | if (vma->vm_flags & VM_SHARED) |
372 | mapping->i_mmap_writable++; |
373 | |
374 | flush_dcache_mmap_lock(mapping); |
375 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
376 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); |
377 | else |
378 | vma_prio_tree_insert(vma, &mapping->i_mmap); |
379 | flush_dcache_mmap_unlock(mapping); |
380 | } |
381 | } |
382 | |
383 | static void |
384 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
385 | struct vm_area_struct *prev, struct rb_node **rb_link, |
386 | struct rb_node *rb_parent) |
387 | { |
388 | __vma_link_list(mm, vma, prev, rb_parent); |
389 | __vma_link_rb(mm, vma, rb_link, rb_parent); |
390 | __anon_vma_link(vma); |
391 | } |
392 | |
393 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
394 | struct vm_area_struct *prev, struct rb_node **rb_link, |
395 | struct rb_node *rb_parent) |
396 | { |
397 | struct address_space *mapping = NULL; |
398 | |
399 | if (vma->vm_file) |
400 | mapping = vma->vm_file->f_mapping; |
401 | |
402 | if (mapping) { |
403 | spin_lock(&mapping->i_mmap_lock); |
404 | vma->vm_truncate_count = mapping->truncate_count; |
405 | } |
406 | anon_vma_lock(vma); |
407 | |
408 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
409 | __vma_link_file(vma); |
410 | |
411 | anon_vma_unlock(vma); |
412 | if (mapping) |
413 | spin_unlock(&mapping->i_mmap_lock); |
414 | |
415 | mm->map_count++; |
416 | validate_mm(mm); |
417 | } |
418 | |
419 | /* |
420 | * Helper for vma_adjust in the split_vma insert case: |
421 | * insert vm structure into list and rbtree and anon_vma, |
422 | * but it has already been inserted into prio_tree earlier. |
423 | */ |
424 | static void |
425 | __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
426 | { |
427 | struct vm_area_struct * __vma, * prev; |
428 | struct rb_node ** rb_link, * rb_parent; |
429 | |
430 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); |
431 | if (__vma && __vma->vm_start < vma->vm_end) |
432 | BUG(); |
433 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
434 | mm->map_count++; |
435 | } |
436 | |
437 | static inline void |
438 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, |
439 | struct vm_area_struct *prev) |
440 | { |
441 | prev->vm_next = vma->vm_next; |
442 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
443 | if (mm->mmap_cache == vma) |
444 | mm->mmap_cache = prev; |
445 | } |
446 | |
447 | /* |
448 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that |
449 | * is already present in an i_mmap tree without adjusting the tree. |
450 | * The following helper function should be used when such adjustments |
451 | * are necessary. The "insert" vma (if any) is to be inserted |
452 | * before we drop the necessary locks. |
453 | */ |
454 | void vma_adjust(struct vm_area_struct *vma, unsigned long start, |
455 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
456 | { |
457 | struct mm_struct *mm = vma->vm_mm; |
458 | struct vm_area_struct *next = vma->vm_next; |
459 | struct vm_area_struct *importer = NULL; |
460 | struct address_space *mapping = NULL; |
461 | struct prio_tree_root *root = NULL; |
462 | struct file *file = vma->vm_file; |
463 | struct anon_vma *anon_vma = NULL; |
464 | long adjust_next = 0; |
465 | int remove_next = 0; |
466 | |
467 | if (next && !insert) { |
468 | if (end >= next->vm_end) { |
469 | /* |
470 | * vma expands, overlapping all the next, and |
471 | * perhaps the one after too (mprotect case 6). |
472 | */ |
473 | again: remove_next = 1 + (end > next->vm_end); |
474 | end = next->vm_end; |
475 | anon_vma = next->anon_vma; |
476 | importer = vma; |
477 | } else if (end > next->vm_start) { |
478 | /* |
479 | * vma expands, overlapping part of the next: |
480 | * mprotect case 5 shifting the boundary up. |
481 | */ |
482 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; |
483 | anon_vma = next->anon_vma; |
484 | importer = vma; |
485 | } else if (end < vma->vm_end) { |
486 | /* |
487 | * vma shrinks, and !insert tells it's not |
488 | * split_vma inserting another: so it must be |
489 | * mprotect case 4 shifting the boundary down. |
490 | */ |
491 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); |
492 | anon_vma = next->anon_vma; |
493 | importer = next; |
494 | } |
495 | } |
496 | |
497 | if (file) { |
498 | mapping = file->f_mapping; |
499 | if (!(vma->vm_flags & VM_NONLINEAR)) |
500 | root = &mapping->i_mmap; |
501 | spin_lock(&mapping->i_mmap_lock); |
502 | if (importer && |
503 | vma->vm_truncate_count != next->vm_truncate_count) { |
504 | /* |
505 | * unmap_mapping_range might be in progress: |
506 | * ensure that the expanding vma is rescanned. |
507 | */ |
508 | importer->vm_truncate_count = 0; |
509 | } |
510 | if (insert) { |
511 | insert->vm_truncate_count = vma->vm_truncate_count; |
512 | /* |
513 | * Put into prio_tree now, so instantiated pages |
514 | * are visible to arm/parisc __flush_dcache_page |
515 | * throughout; but we cannot insert into address |
516 | * space until vma start or end is updated. |
517 | */ |
518 | __vma_link_file(insert); |
519 | } |
520 | } |
521 | |
522 | /* |
523 | * When changing only vma->vm_end, we don't really need |
524 | * anon_vma lock: but is that case worth optimizing out? |
525 | */ |
526 | if (vma->anon_vma) |
527 | anon_vma = vma->anon_vma; |
528 | if (anon_vma) { |
529 | spin_lock(&anon_vma->lock); |
530 | /* |
531 | * Easily overlooked: when mprotect shifts the boundary, |
532 | * make sure the expanding vma has anon_vma set if the |
533 | * shrinking vma had, to cover any anon pages imported. |
534 | */ |
535 | if (importer && !importer->anon_vma) { |
536 | importer->anon_vma = anon_vma; |
537 | __anon_vma_link(importer); |
538 | } |
539 | } |
540 | |
541 | if (root) { |
542 | flush_dcache_mmap_lock(mapping); |
543 | vma_prio_tree_remove(vma, root); |
544 | if (adjust_next) |
545 | vma_prio_tree_remove(next, root); |
546 | } |
547 | |
548 | vma->vm_start = start; |
549 | vma->vm_end = end; |
550 | vma->vm_pgoff = pgoff; |
551 | if (adjust_next) { |
552 | next->vm_start += adjust_next << PAGE_SHIFT; |
553 | next->vm_pgoff += adjust_next; |
554 | } |
555 | |
556 | if (root) { |
557 | if (adjust_next) |
558 | vma_prio_tree_insert(next, root); |
559 | vma_prio_tree_insert(vma, root); |
560 | flush_dcache_mmap_unlock(mapping); |
561 | } |
562 | |
563 | if (remove_next) { |
564 | /* |
565 | * vma_merge has merged next into vma, and needs |
566 | * us to remove next before dropping the locks. |
567 | */ |
568 | __vma_unlink(mm, next, vma); |
569 | if (file) |
570 | __remove_shared_vm_struct(next, file, mapping); |
571 | if (next->anon_vma) |
572 | __anon_vma_merge(vma, next); |
573 | } else if (insert) { |
574 | /* |
575 | * split_vma has split insert from vma, and needs |
576 | * us to insert it before dropping the locks |
577 | * (it may either follow vma or precede it). |
578 | */ |
579 | __insert_vm_struct(mm, insert); |
580 | } |
581 | |
582 | if (anon_vma) |
583 | spin_unlock(&anon_vma->lock); |
584 | if (mapping) |
585 | spin_unlock(&mapping->i_mmap_lock); |
586 | |
587 | if (remove_next) { |
588 | if (file) |
589 | fput(file); |
590 | mm->map_count--; |
591 | mpol_free(vma_policy(next)); |
592 | kmem_cache_free(vm_area_cachep, next); |
593 | /* |
594 | * In mprotect's case 6 (see comments on vma_merge), |
595 | * we must remove another next too. It would clutter |
596 | * up the code too much to do both in one go. |
597 | */ |
598 | if (remove_next == 2) { |
599 | next = vma->vm_next; |
600 | goto again; |
601 | } |
602 | } |
603 | |
604 | validate_mm(mm); |
605 | } |
606 | |
607 | /* |
608 | * If the vma has a ->close operation then the driver probably needs to release |
609 | * per-vma resources, so we don't attempt to merge those. |
610 | */ |
611 | #define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED) |
612 | |
613 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
614 | struct file *file, unsigned long vm_flags) |
615 | { |
616 | if (vma->vm_flags != vm_flags) |
617 | return 0; |
618 | if (vma->vm_file != file) |
619 | return 0; |
620 | if (vma->vm_ops && vma->vm_ops->close) |
621 | return 0; |
622 | return 1; |
623 | } |
624 | |
625 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, |
626 | struct anon_vma *anon_vma2) |
627 | { |
628 | return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); |
629 | } |
630 | |
631 | /* |
632 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
633 | * in front of (at a lower virtual address and file offset than) the vma. |
634 | * |
635 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
636 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
637 | * |
638 | * We don't check here for the merged mmap wrapping around the end of pagecache |
639 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which |
640 | * wrap, nor mmaps which cover the final page at index -1UL. |
641 | */ |
642 | static int |
643 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, |
644 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
645 | { |
646 | if (is_mergeable_vma(vma, file, vm_flags) && |
647 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { |
648 | if (vma->vm_pgoff == vm_pgoff) |
649 | return 1; |
650 | } |
651 | return 0; |
652 | } |
653 | |
654 | /* |
655 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
656 | * beyond (at a higher virtual address and file offset than) the vma. |
657 | * |
658 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
659 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
660 | */ |
661 | static int |
662 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, |
663 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
664 | { |
665 | if (is_mergeable_vma(vma, file, vm_flags) && |
666 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { |
667 | pgoff_t vm_pglen; |
668 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
669 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
670 | return 1; |
671 | } |
672 | return 0; |
673 | } |
674 | |
675 | /* |
676 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out |
677 | * whether that can be merged with its predecessor or its successor. |
678 | * Or both (it neatly fills a hole). |
679 | * |
680 | * In most cases - when called for mmap, brk or mremap - [addr,end) is |
681 | * certain not to be mapped by the time vma_merge is called; but when |
682 | * called for mprotect, it is certain to be already mapped (either at |
683 | * an offset within prev, or at the start of next), and the flags of |
684 | * this area are about to be changed to vm_flags - and the no-change |
685 | * case has already been eliminated. |
686 | * |
687 | * The following mprotect cases have to be considered, where AAAA is |
688 | * the area passed down from mprotect_fixup, never extending beyond one |
689 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: |
690 | * |
691 | * AAAA AAAA AAAA AAAA |
692 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX |
693 | * cannot merge might become might become might become |
694 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or |
695 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or |
696 | * mremap move: PPPPNNNNNNNN 8 |
697 | * AAAA |
698 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN |
699 | * might become case 1 below case 2 below case 3 below |
700 | * |
701 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: |
702 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. |
703 | */ |
704 | struct vm_area_struct *vma_merge(struct mm_struct *mm, |
705 | struct vm_area_struct *prev, unsigned long addr, |
706 | unsigned long end, unsigned long vm_flags, |
707 | struct anon_vma *anon_vma, struct file *file, |
708 | pgoff_t pgoff, struct mempolicy *policy) |
709 | { |
710 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; |
711 | struct vm_area_struct *area, *next; |
712 | |
713 | /* |
714 | * We later require that vma->vm_flags == vm_flags, |
715 | * so this tests vma->vm_flags & VM_SPECIAL, too. |
716 | */ |
717 | if (vm_flags & VM_SPECIAL) |
718 | return NULL; |
719 | |
720 | if (prev) |
721 | next = prev->vm_next; |
722 | else |
723 | next = mm->mmap; |
724 | area = next; |
725 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ |
726 | next = next->vm_next; |
727 | |
728 | /* |
729 | * Can it merge with the predecessor? |
730 | */ |
731 | if (prev && prev->vm_end == addr && |
732 | mpol_equal(vma_policy(prev), policy) && |
733 | can_vma_merge_after(prev, vm_flags, |
734 | anon_vma, file, pgoff)) { |
735 | /* |
736 | * OK, it can. Can we now merge in the successor as well? |
737 | */ |
738 | if (next && end == next->vm_start && |
739 | mpol_equal(policy, vma_policy(next)) && |
740 | can_vma_merge_before(next, vm_flags, |
741 | anon_vma, file, pgoff+pglen) && |
742 | is_mergeable_anon_vma(prev->anon_vma, |
743 | next->anon_vma)) { |
744 | /* cases 1, 6 */ |
745 | vma_adjust(prev, prev->vm_start, |
746 | next->vm_end, prev->vm_pgoff, NULL); |
747 | } else /* cases 2, 5, 7 */ |
748 | vma_adjust(prev, prev->vm_start, |
749 | end, prev->vm_pgoff, NULL); |
750 | return prev; |
751 | } |
752 | |
753 | /* |
754 | * Can this new request be merged in front of next? |
755 | */ |
756 | if (next && end == next->vm_start && |
757 | mpol_equal(policy, vma_policy(next)) && |
758 | can_vma_merge_before(next, vm_flags, |
759 | anon_vma, file, pgoff+pglen)) { |
760 | if (prev && addr < prev->vm_end) /* case 4 */ |
761 | vma_adjust(prev, prev->vm_start, |
762 | addr, prev->vm_pgoff, NULL); |
763 | else /* cases 3, 8 */ |
764 | vma_adjust(area, addr, next->vm_end, |
765 | next->vm_pgoff - pglen, NULL); |
766 | return area; |
767 | } |
768 | |
769 | return NULL; |
770 | } |
771 | |
772 | /* |
773 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check |
774 | * neighbouring vmas for a suitable anon_vma, before it goes off |
775 | * to allocate a new anon_vma. It checks because a repetitive |
776 | * sequence of mprotects and faults may otherwise lead to distinct |
777 | * anon_vmas being allocated, preventing vma merge in subsequent |
778 | * mprotect. |
779 | */ |
780 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) |
781 | { |
782 | struct vm_area_struct *near; |
783 | unsigned long vm_flags; |
784 | |
785 | near = vma->vm_next; |
786 | if (!near) |
787 | goto try_prev; |
788 | |
789 | /* |
790 | * Since only mprotect tries to remerge vmas, match flags |
791 | * which might be mprotected into each other later on. |
792 | * Neither mlock nor madvise tries to remerge at present, |
793 | * so leave their flags as obstructing a merge. |
794 | */ |
795 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); |
796 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); |
797 | |
798 | if (near->anon_vma && vma->vm_end == near->vm_start && |
799 | mpol_equal(vma_policy(vma), vma_policy(near)) && |
800 | can_vma_merge_before(near, vm_flags, |
801 | NULL, vma->vm_file, vma->vm_pgoff + |
802 | ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) |
803 | return near->anon_vma; |
804 | try_prev: |
805 | /* |
806 | * It is potentially slow to have to call find_vma_prev here. |
807 | * But it's only on the first write fault on the vma, not |
808 | * every time, and we could devise a way to avoid it later |
809 | * (e.g. stash info in next's anon_vma_node when assigning |
810 | * an anon_vma, or when trying vma_merge). Another time. |
811 | */ |
812 | if (find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma) |
813 | BUG(); |
814 | if (!near) |
815 | goto none; |
816 | |
817 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); |
818 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); |
819 | |
820 | if (near->anon_vma && near->vm_end == vma->vm_start && |
821 | mpol_equal(vma_policy(near), vma_policy(vma)) && |
822 | can_vma_merge_after(near, vm_flags, |
823 | NULL, vma->vm_file, vma->vm_pgoff)) |
824 | return near->anon_vma; |
825 | none: |
826 | /* |
827 | * There's no absolute need to look only at touching neighbours: |
828 | * we could search further afield for "compatible" anon_vmas. |
829 | * But it would probably just be a waste of time searching, |
830 | * or lead to too many vmas hanging off the same anon_vma. |
831 | * We're trying to allow mprotect remerging later on, |
832 | * not trying to minimize memory used for anon_vmas. |
833 | */ |
834 | return NULL; |
835 | } |
836 | |
837 | #ifdef CONFIG_PROC_FS |
838 | void __vm_stat_account(struct mm_struct *mm, unsigned long flags, |
839 | struct file *file, long pages) |
840 | { |
841 | const unsigned long stack_flags |
842 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); |
843 | |
844 | #ifdef CONFIG_HUGETLB |
845 | if (flags & VM_HUGETLB) { |
846 | if (!(flags & VM_DONTCOPY)) |
847 | mm->shared_vm += pages; |
848 | return; |
849 | } |
850 | #endif /* CONFIG_HUGETLB */ |
851 | |
852 | if (file) { |
853 | mm->shared_vm += pages; |
854 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) |
855 | mm->exec_vm += pages; |
856 | } else if (flags & stack_flags) |
857 | mm->stack_vm += pages; |
858 | if (flags & (VM_RESERVED|VM_IO)) |
859 | mm->reserved_vm += pages; |
860 | } |
861 | #endif /* CONFIG_PROC_FS */ |
862 | |
863 | /* |
864 | * The caller must hold down_write(current->mm->mmap_sem). |
865 | */ |
866 | |
867 | unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, |
868 | unsigned long len, unsigned long prot, |
869 | unsigned long flags, unsigned long pgoff) |
870 | { |
871 | struct mm_struct * mm = current->mm; |
872 | struct vm_area_struct * vma, * prev; |
873 | struct inode *inode; |
874 | unsigned int vm_flags; |
875 | int correct_wcount = 0; |
876 | int error; |
877 | struct rb_node ** rb_link, * rb_parent; |
878 | int accountable = 1; |
879 | unsigned long charged = 0, reqprot = prot; |
880 | |
881 | if (file) { |
882 | if (is_file_hugepages(file)) |
883 | accountable = 0; |
884 | |
885 | if (!file->f_op || !file->f_op->mmap) |
886 | return -ENODEV; |
887 | |
888 | if ((prot & PROT_EXEC) && |
889 | (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)) |
890 | return -EPERM; |
891 | } |
892 | /* |
893 | * Does the application expect PROT_READ to imply PROT_EXEC? |
894 | * |
895 | * (the exception is when the underlying filesystem is noexec |
896 | * mounted, in which case we dont add PROT_EXEC.) |
897 | */ |
898 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
899 | if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))) |
900 | prot |= PROT_EXEC; |
901 | |
902 | if (!len) |
903 | return -EINVAL; |
904 | |
905 | /* Careful about overflows.. */ |
906 | len = PAGE_ALIGN(len); |
907 | if (!len || len > TASK_SIZE) |
908 | return -ENOMEM; |
909 | |
910 | /* offset overflow? */ |
911 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
912 | return -EOVERFLOW; |
913 | |
914 | /* Too many mappings? */ |
915 | if (mm->map_count > sysctl_max_map_count) |
916 | return -ENOMEM; |
917 | |
918 | /* Obtain the address to map to. we verify (or select) it and ensure |
919 | * that it represents a valid section of the address space. |
920 | */ |
921 | addr = get_unmapped_area(file, addr, len, pgoff, flags); |
922 | if (addr & ~PAGE_MASK) |
923 | return addr; |
924 | |
925 | /* Do simple checking here so the lower-level routines won't have |
926 | * to. we assume access permissions have been handled by the open |
927 | * of the memory object, so we don't do any here. |
928 | */ |
929 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | |
930 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
931 | |
932 | if (flags & MAP_LOCKED) { |
933 | if (!can_do_mlock()) |
934 | return -EPERM; |
935 | vm_flags |= VM_LOCKED; |
936 | } |
937 | /* mlock MCL_FUTURE? */ |
938 | if (vm_flags & VM_LOCKED) { |
939 | unsigned long locked, lock_limit; |
940 | locked = len >> PAGE_SHIFT; |
941 | locked += mm->locked_vm; |
942 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
943 | lock_limit >>= PAGE_SHIFT; |
944 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
945 | return -EAGAIN; |
946 | } |
947 | |
948 | inode = file ? file->f_dentry->d_inode : NULL; |
949 | |
950 | if (file) { |
951 | switch (flags & MAP_TYPE) { |
952 | case MAP_SHARED: |
953 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) |
954 | return -EACCES; |
955 | |
956 | /* |
957 | * Make sure we don't allow writing to an append-only |
958 | * file.. |
959 | */ |
960 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) |
961 | return -EACCES; |
962 | |
963 | /* |
964 | * Make sure there are no mandatory locks on the file. |
965 | */ |
966 | if (locks_verify_locked(inode)) |
967 | return -EAGAIN; |
968 | |
969 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
970 | if (!(file->f_mode & FMODE_WRITE)) |
971 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); |
972 | |
973 | /* fall through */ |
974 | case MAP_PRIVATE: |
975 | if (!(file->f_mode & FMODE_READ)) |
976 | return -EACCES; |
977 | break; |
978 | |
979 | default: |
980 | return -EINVAL; |
981 | } |
982 | } else { |
983 | switch (flags & MAP_TYPE) { |
984 | case MAP_SHARED: |
985 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
986 | break; |
987 | case MAP_PRIVATE: |
988 | /* |
989 | * Set pgoff according to addr for anon_vma. |
990 | */ |
991 | pgoff = addr >> PAGE_SHIFT; |
992 | break; |
993 | default: |
994 | return -EINVAL; |
995 | } |
996 | } |
997 | |
998 | error = security_file_mmap(file, reqprot, prot, flags); |
999 | if (error) |
1000 | return error; |
1001 | |
1002 | /* Clear old maps */ |
1003 | error = -ENOMEM; |
1004 | munmap_back: |
1005 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
1006 | if (vma && vma->vm_start < addr + len) { |
1007 | if (do_munmap(mm, addr, len)) |
1008 | return -ENOMEM; |
1009 | goto munmap_back; |
1010 | } |
1011 | |
1012 | /* Check against address space limit. */ |
1013 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1014 | return -ENOMEM; |
1015 | |
1016 | if (accountable && (!(flags & MAP_NORESERVE) || |
1017 | sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { |
1018 | if (vm_flags & VM_SHARED) { |
1019 | /* Check memory availability in shmem_file_setup? */ |
1020 | vm_flags |= VM_ACCOUNT; |
1021 | } else if (vm_flags & VM_WRITE) { |
1022 | /* |
1023 | * Private writable mapping: check memory availability |
1024 | */ |
1025 | charged = len >> PAGE_SHIFT; |
1026 | if (security_vm_enough_memory(charged)) |
1027 | return -ENOMEM; |
1028 | vm_flags |= VM_ACCOUNT; |
1029 | } |
1030 | } |
1031 | |
1032 | /* |
1033 | * Can we just expand an old private anonymous mapping? |
1034 | * The VM_SHARED test is necessary because shmem_zero_setup |
1035 | * will create the file object for a shared anonymous map below. |
1036 | */ |
1037 | if (!file && !(vm_flags & VM_SHARED) && |
1038 | vma_merge(mm, prev, addr, addr + len, vm_flags, |
1039 | NULL, NULL, pgoff, NULL)) |
1040 | goto out; |
1041 | |
1042 | /* |
1043 | * Determine the object being mapped and call the appropriate |
1044 | * specific mapper. the address has already been validated, but |
1045 | * not unmapped, but the maps are removed from the list. |
1046 | */ |
1047 | vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
1048 | if (!vma) { |
1049 | error = -ENOMEM; |
1050 | goto unacct_error; |
1051 | } |
1052 | memset(vma, 0, sizeof(*vma)); |
1053 | |
1054 | vma->vm_mm = mm; |
1055 | vma->vm_start = addr; |
1056 | vma->vm_end = addr + len; |
1057 | vma->vm_flags = vm_flags; |
1058 | vma->vm_page_prot = protection_map[vm_flags & 0x0f]; |
1059 | vma->vm_pgoff = pgoff; |
1060 | |
1061 | if (file) { |
1062 | error = -EINVAL; |
1063 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1064 | goto free_vma; |
1065 | if (vm_flags & VM_DENYWRITE) { |
1066 | error = deny_write_access(file); |
1067 | if (error) |
1068 | goto free_vma; |
1069 | correct_wcount = 1; |
1070 | } |
1071 | vma->vm_file = file; |
1072 | get_file(file); |
1073 | error = file->f_op->mmap(file, vma); |
1074 | if (error) |
1075 | goto unmap_and_free_vma; |
1076 | } else if (vm_flags & VM_SHARED) { |
1077 | error = shmem_zero_setup(vma); |
1078 | if (error) |
1079 | goto free_vma; |
1080 | } |
1081 | |
1082 | /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform |
1083 | * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) |
1084 | * that memory reservation must be checked; but that reservation |
1085 | * belongs to shared memory object, not to vma: so now clear it. |
1086 | */ |
1087 | if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) |
1088 | vma->vm_flags &= ~VM_ACCOUNT; |
1089 | |
1090 | /* Can addr have changed?? |
1091 | * |
1092 | * Answer: Yes, several device drivers can do it in their |
1093 | * f_op->mmap method. -DaveM |
1094 | */ |
1095 | addr = vma->vm_start; |
1096 | pgoff = vma->vm_pgoff; |
1097 | vm_flags = vma->vm_flags; |
1098 | |
1099 | if (!file || !vma_merge(mm, prev, addr, vma->vm_end, |
1100 | vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { |
1101 | file = vma->vm_file; |
1102 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1103 | if (correct_wcount) |
1104 | atomic_inc(&inode->i_writecount); |
1105 | } else { |
1106 | if (file) { |
1107 | if (correct_wcount) |
1108 | atomic_inc(&inode->i_writecount); |
1109 | fput(file); |
1110 | } |
1111 | mpol_free(vma_policy(vma)); |
1112 | kmem_cache_free(vm_area_cachep, vma); |
1113 | } |
1114 | out: |
1115 | mm->total_vm += len >> PAGE_SHIFT; |
1116 | __vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1117 | if (vm_flags & VM_LOCKED) { |
1118 | mm->locked_vm += len >> PAGE_SHIFT; |
1119 | make_pages_present(addr, addr + len); |
1120 | } |
1121 | if (flags & MAP_POPULATE) { |
1122 | up_write(&mm->mmap_sem); |
1123 | sys_remap_file_pages(addr, len, 0, |
1124 | pgoff, flags & MAP_NONBLOCK); |
1125 | down_write(&mm->mmap_sem); |
1126 | } |
1127 | return addr; |
1128 | |
1129 | unmap_and_free_vma: |
1130 | if (correct_wcount) |
1131 | atomic_inc(&inode->i_writecount); |
1132 | vma->vm_file = NULL; |
1133 | fput(file); |
1134 | |
1135 | /* Undo any partial mapping done by a device driver. */ |
1136 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1137 | charged = 0; |
1138 | free_vma: |
1139 | kmem_cache_free(vm_area_cachep, vma); |
1140 | unacct_error: |
1141 | if (charged) |
1142 | vm_unacct_memory(charged); |
1143 | return error; |
1144 | } |
1145 | |
1146 | EXPORT_SYMBOL(do_mmap_pgoff); |
1147 | |
1148 | /* Get an address range which is currently unmapped. |
1149 | * For shmat() with addr=0. |
1150 | * |
1151 | * Ugly calling convention alert: |
1152 | * Return value with the low bits set means error value, |
1153 | * ie |
1154 | * if (ret & ~PAGE_MASK) |
1155 | * error = ret; |
1156 | * |
1157 | * This function "knows" that -ENOMEM has the bits set. |
1158 | */ |
1159 | #ifndef HAVE_ARCH_UNMAPPED_AREA |
1160 | unsigned long |
1161 | arch_get_unmapped_area(struct file *filp, unsigned long addr, |
1162 | unsigned long len, unsigned long pgoff, unsigned long flags) |
1163 | { |
1164 | struct mm_struct *mm = current->mm; |
1165 | struct vm_area_struct *vma; |
1166 | unsigned long start_addr; |
1167 | |
1168 | if (len > TASK_SIZE) |
1169 | return -ENOMEM; |
1170 | |
1171 | if (addr) { |
1172 | addr = PAGE_ALIGN(addr); |
1173 | vma = find_vma(mm, addr); |
1174 | if (TASK_SIZE - len >= addr && |
1175 | (!vma || addr + len <= vma->vm_start)) |
1176 | return addr; |
1177 | } |
1178 | start_addr = addr = mm->free_area_cache; |
1179 | |
1180 | full_search: |
1181 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { |
1182 | /* At this point: (!vma || addr < vma->vm_end). */ |
1183 | if (TASK_SIZE - len < addr) { |
1184 | /* |
1185 | * Start a new search - just in case we missed |
1186 | * some holes. |
1187 | */ |
1188 | if (start_addr != TASK_UNMAPPED_BASE) { |
1189 | start_addr = addr = TASK_UNMAPPED_BASE; |
1190 | goto full_search; |
1191 | } |
1192 | return -ENOMEM; |
1193 | } |
1194 | if (!vma || addr + len <= vma->vm_start) { |
1195 | /* |
1196 | * Remember the place where we stopped the search: |
1197 | */ |
1198 | mm->free_area_cache = addr + len; |
1199 | return addr; |
1200 | } |
1201 | addr = vma->vm_end; |
1202 | } |
1203 | } |
1204 | #endif |
1205 | |
1206 | void arch_unmap_area(struct vm_area_struct *area) |
1207 | { |
1208 | /* |
1209 | * Is this a new hole at the lowest possible address? |
1210 | */ |
1211 | if (area->vm_start >= TASK_UNMAPPED_BASE && |
1212 | area->vm_start < area->vm_mm->free_area_cache) |
1213 | area->vm_mm->free_area_cache = area->vm_start; |
1214 | } |
1215 | |
1216 | /* |
1217 | * This mmap-allocator allocates new areas top-down from below the |
1218 | * stack's low limit (the base): |
1219 | */ |
1220 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN |
1221 | unsigned long |
1222 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, |
1223 | const unsigned long len, const unsigned long pgoff, |
1224 | const unsigned long flags) |
1225 | { |
1226 | struct vm_area_struct *vma; |
1227 | struct mm_struct *mm = current->mm; |
1228 | unsigned long addr = addr0; |
1229 | |
1230 | /* requested length too big for entire address space */ |
1231 | if (len > TASK_SIZE) |
1232 | return -ENOMEM; |
1233 | |
1234 | /* requesting a specific address */ |
1235 | if (addr) { |
1236 | addr = PAGE_ALIGN(addr); |
1237 | vma = find_vma(mm, addr); |
1238 | if (TASK_SIZE - len >= addr && |
1239 | (!vma || addr + len <= vma->vm_start)) |
1240 | return addr; |
1241 | } |
1242 | |
1243 | /* either no address requested or can't fit in requested address hole */ |
1244 | addr = mm->free_area_cache; |
1245 | |
1246 | /* make sure it can fit in the remaining address space */ |
1247 | if (addr > len) { |
1248 | vma = find_vma(mm, addr-len); |
1249 | if (!vma || addr <= vma->vm_start) |
1250 | /* remember the address as a hint for next time */ |
1251 | return (mm->free_area_cache = addr-len); |
1252 | } |
1253 | |
1254 | addr = mm->mmap_base-len; |
1255 | |
1256 | do { |
1257 | /* |
1258 | * Lookup failure means no vma is above this address, |
1259 | * else if new region fits below vma->vm_start, |
1260 | * return with success: |
1261 | */ |
1262 | vma = find_vma(mm, addr); |
1263 | if (!vma || addr+len <= vma->vm_start) |
1264 | /* remember the address as a hint for next time */ |
1265 | return (mm->free_area_cache = addr); |
1266 | |
1267 | /* try just below the current vma->vm_start */ |
1268 | addr = vma->vm_start-len; |
1269 | } while (len < vma->vm_start); |
1270 | |
1271 | /* |
1272 | * A failed mmap() very likely causes application failure, |
1273 | * so fall back to the bottom-up function here. This scenario |
1274 | * can happen with large stack limits and large mmap() |
1275 | * allocations. |
1276 | */ |
1277 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
1278 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1279 | /* |
1280 | * Restore the topdown base: |
1281 | */ |
1282 | mm->free_area_cache = mm->mmap_base; |
1283 | |
1284 | return addr; |
1285 | } |
1286 | #endif |
1287 | |
1288 | void arch_unmap_area_topdown(struct vm_area_struct *area) |
1289 | { |
1290 | /* |
1291 | * Is this a new hole at the highest possible address? |
1292 | */ |
1293 | if (area->vm_end > area->vm_mm->free_area_cache) |
1294 | area->vm_mm->free_area_cache = area->vm_end; |
1295 | |
1296 | /* dont allow allocations above current base */ |
1297 | if (area->vm_mm->free_area_cache > area->vm_mm->mmap_base) |
1298 | area->vm_mm->free_area_cache = area->vm_mm->mmap_base; |
1299 | } |
1300 | |
1301 | unsigned long |
1302 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, |
1303 | unsigned long pgoff, unsigned long flags) |
1304 | { |
1305 | unsigned long ret; |
1306 | |
1307 | if (!(flags & MAP_FIXED)) { |
1308 | unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); |
1309 | |
1310 | get_area = current->mm->get_unmapped_area; |
1311 | if (file && file->f_op && file->f_op->get_unmapped_area) |
1312 | get_area = file->f_op->get_unmapped_area; |
1313 | addr = get_area(file, addr, len, pgoff, flags); |
1314 | if (IS_ERR_VALUE(addr)) |
1315 | return addr; |
1316 | } |
1317 | |
1318 | if (addr > TASK_SIZE - len) |
1319 | return -ENOMEM; |
1320 | if (addr & ~PAGE_MASK) |
1321 | return -EINVAL; |
1322 | if (file && is_file_hugepages(file)) { |
1323 | /* |
1324 | * Check if the given range is hugepage aligned, and |
1325 | * can be made suitable for hugepages. |
1326 | */ |
1327 | ret = prepare_hugepage_range(addr, len); |
1328 | } else { |
1329 | /* |
1330 | * Ensure that a normal request is not falling in a |
1331 | * reserved hugepage range. For some archs like IA-64, |
1332 | * there is a separate region for hugepages. |
1333 | */ |
1334 | ret = is_hugepage_only_range(current->mm, addr, len); |
1335 | } |
1336 | if (ret) |
1337 | return -EINVAL; |
1338 | return addr; |
1339 | } |
1340 | |
1341 | EXPORT_SYMBOL(get_unmapped_area); |
1342 | |
1343 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ |
1344 | struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) |
1345 | { |
1346 | struct vm_area_struct *vma = NULL; |
1347 | |
1348 | if (mm) { |
1349 | /* Check the cache first. */ |
1350 | /* (Cache hit rate is typically around 35%.) */ |
1351 | vma = mm->mmap_cache; |
1352 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { |
1353 | struct rb_node * rb_node; |
1354 | |
1355 | rb_node = mm->mm_rb.rb_node; |
1356 | vma = NULL; |
1357 | |
1358 | while (rb_node) { |
1359 | struct vm_area_struct * vma_tmp; |
1360 | |
1361 | vma_tmp = rb_entry(rb_node, |
1362 | struct vm_area_struct, vm_rb); |
1363 | |
1364 | if (vma_tmp->vm_end > addr) { |
1365 | vma = vma_tmp; |
1366 | if (vma_tmp->vm_start <= addr) |
1367 | break; |
1368 | rb_node = rb_node->rb_left; |
1369 | } else |
1370 | rb_node = rb_node->rb_right; |
1371 | } |
1372 | if (vma) |
1373 | mm->mmap_cache = vma; |
1374 | } |
1375 | } |
1376 | return vma; |
1377 | } |
1378 | |
1379 | EXPORT_SYMBOL(find_vma); |
1380 | |
1381 | /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ |
1382 | struct vm_area_struct * |
1383 | find_vma_prev(struct mm_struct *mm, unsigned long addr, |
1384 | struct vm_area_struct **pprev) |
1385 | { |
1386 | struct vm_area_struct *vma = NULL, *prev = NULL; |
1387 | struct rb_node * rb_node; |
1388 | if (!mm) |
1389 | goto out; |
1390 | |
1391 | /* Guard against addr being lower than the first VMA */ |
1392 | vma = mm->mmap; |
1393 | |
1394 | /* Go through the RB tree quickly. */ |
1395 | rb_node = mm->mm_rb.rb_node; |
1396 | |
1397 | while (rb_node) { |
1398 | struct vm_area_struct *vma_tmp; |
1399 | vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); |
1400 | |
1401 | if (addr < vma_tmp->vm_end) { |
1402 | rb_node = rb_node->rb_left; |
1403 | } else { |
1404 | prev = vma_tmp; |
1405 | if (!prev->vm_next || (addr < prev->vm_next->vm_end)) |
1406 | break; |
1407 | rb_node = rb_node->rb_right; |
1408 | } |
1409 | } |
1410 | |
1411 | out: |
1412 | *pprev = prev; |
1413 | return prev ? prev->vm_next : vma; |
1414 | } |
1415 | |
1416 | /* |
1417 | * Verify that the stack growth is acceptable and |
1418 | * update accounting. This is shared with both the |
1419 | * grow-up and grow-down cases. |
1420 | */ |
1421 | static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) |
1422 | { |
1423 | struct mm_struct *mm = vma->vm_mm; |
1424 | struct rlimit *rlim = current->signal->rlim; |
1425 | |
1426 | /* address space limit tests */ |
1427 | if (!may_expand_vm(mm, grow)) |
1428 | return -ENOMEM; |
1429 | |
1430 | /* Stack limit test */ |
1431 | if (size > rlim[RLIMIT_STACK].rlim_cur) |
1432 | return -ENOMEM; |
1433 | |
1434 | /* mlock limit tests */ |
1435 | if (vma->vm_flags & VM_LOCKED) { |
1436 | unsigned long locked; |
1437 | unsigned long limit; |
1438 | locked = mm->locked_vm + grow; |
1439 | limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; |
1440 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
1441 | return -ENOMEM; |
1442 | } |
1443 | |
1444 | /* |
1445 | * Overcommit.. This must be the final test, as it will |
1446 | * update security statistics. |
1447 | */ |
1448 | if (security_vm_enough_memory(grow)) |
1449 | return -ENOMEM; |
1450 | |
1451 | /* Ok, everything looks good - let it rip */ |
1452 | mm->total_vm += grow; |
1453 | if (vma->vm_flags & VM_LOCKED) |
1454 | mm->locked_vm += grow; |
1455 | __vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1456 | return 0; |
1457 | } |
1458 | |
1459 | #ifdef CONFIG_STACK_GROWSUP |
1460 | /* |
1461 | * vma is the first one with address > vma->vm_end. Have to extend vma. |
1462 | */ |
1463 | int expand_stack(struct vm_area_struct * vma, unsigned long address) |
1464 | { |
1465 | int error; |
1466 | |
1467 | if (!(vma->vm_flags & VM_GROWSUP)) |
1468 | return -EFAULT; |
1469 | |
1470 | /* |
1471 | * We must make sure the anon_vma is allocated |
1472 | * so that the anon_vma locking is not a noop. |
1473 | */ |
1474 | if (unlikely(anon_vma_prepare(vma))) |
1475 | return -ENOMEM; |
1476 | anon_vma_lock(vma); |
1477 | |
1478 | /* |
1479 | * vma->vm_start/vm_end cannot change under us because the caller |
1480 | * is required to hold the mmap_sem in read mode. We need the |
1481 | * anon_vma lock to serialize against concurrent expand_stacks. |
1482 | */ |
1483 | address += 4 + PAGE_SIZE - 1; |
1484 | address &= PAGE_MASK; |
1485 | error = 0; |
1486 | |
1487 | /* Somebody else might have raced and expanded it already */ |
1488 | if (address > vma->vm_end) { |
1489 | unsigned long size, grow; |
1490 | |
1491 | size = address - vma->vm_start; |
1492 | grow = (address - vma->vm_end) >> PAGE_SHIFT; |
1493 | |
1494 | error = acct_stack_growth(vma, size, grow); |
1495 | if (!error) |
1496 | vma->vm_end = address; |
1497 | } |
1498 | anon_vma_unlock(vma); |
1499 | return error; |
1500 | } |
1501 | |
1502 | struct vm_area_struct * |
1503 | find_extend_vma(struct mm_struct *mm, unsigned long addr) |
1504 | { |
1505 | struct vm_area_struct *vma, *prev; |
1506 | |
1507 | addr &= PAGE_MASK; |
1508 | vma = find_vma_prev(mm, addr, &prev); |
1509 | if (vma && (vma->vm_start <= addr)) |
1510 | return vma; |
1511 | if (!prev || expand_stack(prev, addr)) |
1512 | return NULL; |
1513 | if (prev->vm_flags & VM_LOCKED) { |
1514 | make_pages_present(addr, prev->vm_end); |
1515 | } |
1516 | return prev; |
1517 | } |
1518 | #else |
1519 | /* |
1520 | * vma is the first one with address < vma->vm_start. Have to extend vma. |
1521 | */ |
1522 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
1523 | { |
1524 | int error; |
1525 | |
1526 | /* |
1527 | * We must make sure the anon_vma is allocated |
1528 | * so that the anon_vma locking is not a noop. |
1529 | */ |
1530 | if (unlikely(anon_vma_prepare(vma))) |
1531 | return -ENOMEM; |
1532 | anon_vma_lock(vma); |
1533 | |
1534 | /* |
1535 | * vma->vm_start/vm_end cannot change under us because the caller |
1536 | * is required to hold the mmap_sem in read mode. We need the |
1537 | * anon_vma lock to serialize against concurrent expand_stacks. |
1538 | */ |
1539 | address &= PAGE_MASK; |
1540 | error = 0; |
1541 | |
1542 | /* Somebody else might have raced and expanded it already */ |
1543 | if (address < vma->vm_start) { |
1544 | unsigned long size, grow; |
1545 | |
1546 | size = vma->vm_end - address; |
1547 | grow = (vma->vm_start - address) >> PAGE_SHIFT; |
1548 | |
1549 | error = acct_stack_growth(vma, size, grow); |
1550 | if (!error) { |
1551 | vma->vm_start = address; |
1552 | vma->vm_pgoff -= grow; |
1553 | } |
1554 | } |
1555 | anon_vma_unlock(vma); |
1556 | return error; |
1557 | } |
1558 | |
1559 | struct vm_area_struct * |
1560 | find_extend_vma(struct mm_struct * mm, unsigned long addr) |
1561 | { |
1562 | struct vm_area_struct * vma; |
1563 | unsigned long start; |
1564 | |
1565 | addr &= PAGE_MASK; |
1566 | vma = find_vma(mm,addr); |
1567 | if (!vma) |
1568 | return NULL; |
1569 | if (vma->vm_start <= addr) |
1570 | return vma; |
1571 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
1572 | return NULL; |
1573 | start = vma->vm_start; |
1574 | if (expand_stack(vma, addr)) |
1575 | return NULL; |
1576 | if (vma->vm_flags & VM_LOCKED) { |
1577 | make_pages_present(addr, start); |
1578 | } |
1579 | return vma; |
1580 | } |
1581 | #endif |
1582 | |
1583 | /* Normal function to fix up a mapping |
1584 | * This function is the default for when an area has no specific |
1585 | * function. This may be used as part of a more specific routine. |
1586 | * |
1587 | * By the time this function is called, the area struct has been |
1588 | * removed from the process mapping list. |
1589 | */ |
1590 | static void unmap_vma(struct mm_struct *mm, struct vm_area_struct *area) |
1591 | { |
1592 | size_t len = area->vm_end - area->vm_start; |
1593 | |
1594 | area->vm_mm->total_vm -= len >> PAGE_SHIFT; |
1595 | if (area->vm_flags & VM_LOCKED) |
1596 | area->vm_mm->locked_vm -= len >> PAGE_SHIFT; |
1597 | vm_stat_unaccount(area); |
1598 | area->vm_mm->unmap_area(area); |
1599 | remove_vm_struct(area); |
1600 | } |
1601 | |
1602 | /* |
1603 | * Update the VMA and inode share lists. |
1604 | * |
1605 | * Ok - we have the memory areas we should free on the 'free' list, |
1606 | * so release them, and do the vma updates. |
1607 | */ |
1608 | static void unmap_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1609 | { |
1610 | do { |
1611 | struct vm_area_struct *next = vma->vm_next; |
1612 | unmap_vma(mm, vma); |
1613 | vma = next; |
1614 | } while (vma); |
1615 | validate_mm(mm); |
1616 | } |
1617 | |
1618 | /* |
1619 | * Get rid of page table information in the indicated region. |
1620 | * |
1621 | * Called with the page table lock held. |
1622 | */ |
1623 | static void unmap_region(struct mm_struct *mm, |
1624 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1625 | unsigned long start, unsigned long end) |
1626 | { |
1627 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
1628 | struct mmu_gather *tlb; |
1629 | unsigned long nr_accounted = 0; |
1630 | |
1631 | lru_add_drain(); |
1632 | spin_lock(&mm->page_table_lock); |
1633 | tlb = tlb_gather_mmu(mm, 0); |
1634 | unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL); |
1635 | vm_unacct_memory(nr_accounted); |
1636 | free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, |
1637 | next? next->vm_start: 0); |
1638 | tlb_finish_mmu(tlb, start, end); |
1639 | spin_unlock(&mm->page_table_lock); |
1640 | } |
1641 | |
1642 | /* |
1643 | * Create a list of vma's touched by the unmap, removing them from the mm's |
1644 | * vma list as we go.. |
1645 | */ |
1646 | static void |
1647 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, |
1648 | struct vm_area_struct *prev, unsigned long end) |
1649 | { |
1650 | struct vm_area_struct **insertion_point; |
1651 | struct vm_area_struct *tail_vma = NULL; |
1652 | |
1653 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); |
1654 | do { |
1655 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
1656 | mm->map_count--; |
1657 | tail_vma = vma; |
1658 | vma = vma->vm_next; |
1659 | } while (vma && vma->vm_start < end); |
1660 | *insertion_point = vma; |
1661 | tail_vma->vm_next = NULL; |
1662 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1663 | } |
1664 | |
1665 | /* |
1666 | * Split a vma into two pieces at address 'addr', a new vma is allocated |
1667 | * either for the first part or the the tail. |
1668 | */ |
1669 | int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1670 | unsigned long addr, int new_below) |
1671 | { |
1672 | struct mempolicy *pol; |
1673 | struct vm_area_struct *new; |
1674 | |
1675 | if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) |
1676 | return -EINVAL; |
1677 | |
1678 | if (mm->map_count >= sysctl_max_map_count) |
1679 | return -ENOMEM; |
1680 | |
1681 | new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
1682 | if (!new) |
1683 | return -ENOMEM; |
1684 | |
1685 | /* most fields are the same, copy all, and then fixup */ |
1686 | *new = *vma; |
1687 | |
1688 | if (new_below) |
1689 | new->vm_end = addr; |
1690 | else { |
1691 | new->vm_start = addr; |
1692 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); |
1693 | } |
1694 | |
1695 | pol = mpol_copy(vma_policy(vma)); |
1696 | if (IS_ERR(pol)) { |
1697 | kmem_cache_free(vm_area_cachep, new); |
1698 | return PTR_ERR(pol); |
1699 | } |
1700 | vma_set_policy(new, pol); |
1701 | |
1702 | if (new->vm_file) |
1703 | get_file(new->vm_file); |
1704 | |
1705 | if (new->vm_ops && new->vm_ops->open) |
1706 | new->vm_ops->open(new); |
1707 | |
1708 | if (new_below) |
1709 | vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1710 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
1711 | else |
1712 | vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1713 | |
1714 | return 0; |
1715 | } |
1716 | |
1717 | /* Munmap is split into 2 main parts -- this part which finds |
1718 | * what needs doing, and the areas themselves, which do the |
1719 | * work. This now handles partial unmappings. |
1720 | * Jeremy Fitzhardinge <jeremy@goop.org> |
1721 | */ |
1722 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
1723 | { |
1724 | unsigned long end; |
1725 | struct vm_area_struct *vma, *prev, *last; |
1726 | |
1727 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) |
1728 | return -EINVAL; |
1729 | |
1730 | if ((len = PAGE_ALIGN(len)) == 0) |
1731 | return -EINVAL; |
1732 | |
1733 | /* Find the first overlapping VMA */ |
1734 | vma = find_vma_prev(mm, start, &prev); |
1735 | if (!vma) |
1736 | return 0; |
1737 | /* we have start < vma->vm_end */ |
1738 | |
1739 | /* if it doesn't overlap, we have nothing.. */ |
1740 | end = start + len; |
1741 | if (vma->vm_start >= end) |
1742 | return 0; |
1743 | |
1744 | /* |
1745 | * If we need to split any vma, do it now to save pain later. |
1746 | * |
1747 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially |
1748 | * unmapped vm_area_struct will remain in use: so lower split_vma |
1749 | * places tmp vma above, and higher split_vma places tmp vma below. |
1750 | */ |
1751 | if (start > vma->vm_start) { |
1752 | int error = split_vma(mm, vma, start, 0); |
1753 | if (error) |
1754 | return error; |
1755 | prev = vma; |
1756 | } |
1757 | |
1758 | /* Does it split the last one? */ |
1759 | last = find_vma(mm, end); |
1760 | if (last && end > last->vm_start) { |
1761 | int error = split_vma(mm, last, end, 1); |
1762 | if (error) |
1763 | return error; |
1764 | } |
1765 | vma = prev? prev->vm_next: mm->mmap; |
1766 | |
1767 | /* |
1768 | * Remove the vma's, and unmap the actual pages |
1769 | */ |
1770 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
1771 | unmap_region(mm, vma, prev, start, end); |
1772 | |
1773 | /* Fix up all other VM information */ |
1774 | unmap_vma_list(mm, vma); |
1775 | |
1776 | return 0; |
1777 | } |
1778 | |
1779 | EXPORT_SYMBOL(do_munmap); |
1780 | |
1781 | asmlinkage long sys_munmap(unsigned long addr, size_t len) |
1782 | { |
1783 | int ret; |
1784 | struct mm_struct *mm = current->mm; |
1785 | |
1786 | profile_munmap(addr); |
1787 | |
1788 | down_write(&mm->mmap_sem); |
1789 | ret = do_munmap(mm, addr, len); |
1790 | up_write(&mm->mmap_sem); |
1791 | return ret; |
1792 | } |
1793 | |
1794 | static inline void verify_mm_writelocked(struct mm_struct *mm) |
1795 | { |
1796 | #ifdef CONFIG_DEBUG_KERNEL |
1797 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
1798 | WARN_ON(1); |
1799 | up_read(&mm->mmap_sem); |
1800 | } |
1801 | #endif |
1802 | } |
1803 | |
1804 | /* |
1805 | * this is really a simplified "do_mmap". it only handles |
1806 | * anonymous maps. eventually we may be able to do some |
1807 | * brk-specific accounting here. |
1808 | */ |
1809 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1810 | { |
1811 | struct mm_struct * mm = current->mm; |
1812 | struct vm_area_struct * vma, * prev; |
1813 | unsigned long flags; |
1814 | struct rb_node ** rb_link, * rb_parent; |
1815 | pgoff_t pgoff = addr >> PAGE_SHIFT; |
1816 | |
1817 | len = PAGE_ALIGN(len); |
1818 | if (!len) |
1819 | return addr; |
1820 | |
1821 | if ((addr + len) > TASK_SIZE || (addr + len) < addr) |
1822 | return -EINVAL; |
1823 | |
1824 | /* |
1825 | * mlock MCL_FUTURE? |
1826 | */ |
1827 | if (mm->def_flags & VM_LOCKED) { |
1828 | unsigned long locked, lock_limit; |
1829 | locked = len >> PAGE_SHIFT; |
1830 | locked += mm->locked_vm; |
1831 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
1832 | lock_limit >>= PAGE_SHIFT; |
1833 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1834 | return -EAGAIN; |
1835 | } |
1836 | |
1837 | /* |
1838 | * mm->mmap_sem is required to protect against another thread |
1839 | * changing the mappings in case we sleep. |
1840 | */ |
1841 | verify_mm_writelocked(mm); |
1842 | |
1843 | /* |
1844 | * Clear old maps. this also does some error checking for us |
1845 | */ |
1846 | munmap_back: |
1847 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
1848 | if (vma && vma->vm_start < addr + len) { |
1849 | if (do_munmap(mm, addr, len)) |
1850 | return -ENOMEM; |
1851 | goto munmap_back; |
1852 | } |
1853 | |
1854 | /* Check against address space limits *after* clearing old maps... */ |
1855 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1856 | return -ENOMEM; |
1857 | |
1858 | if (mm->map_count > sysctl_max_map_count) |
1859 | return -ENOMEM; |
1860 | |
1861 | if (security_vm_enough_memory(len >> PAGE_SHIFT)) |
1862 | return -ENOMEM; |
1863 | |
1864 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
1865 | |
1866 | /* Can we just expand an old private anonymous mapping? */ |
1867 | if (vma_merge(mm, prev, addr, addr + len, flags, |
1868 | NULL, NULL, pgoff, NULL)) |
1869 | goto out; |
1870 | |
1871 | /* |
1872 | * create a vma struct for an anonymous mapping |
1873 | */ |
1874 | vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
1875 | if (!vma) { |
1876 | vm_unacct_memory(len >> PAGE_SHIFT); |
1877 | return -ENOMEM; |
1878 | } |
1879 | memset(vma, 0, sizeof(*vma)); |
1880 | |
1881 | vma->vm_mm = mm; |
1882 | vma->vm_start = addr; |
1883 | vma->vm_end = addr + len; |
1884 | vma->vm_pgoff = pgoff; |
1885 | vma->vm_flags = flags; |
1886 | vma->vm_page_prot = protection_map[flags & 0x0f]; |
1887 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1888 | out: |
1889 | mm->total_vm += len >> PAGE_SHIFT; |
1890 | if (flags & VM_LOCKED) { |
1891 | mm->locked_vm += len >> PAGE_SHIFT; |
1892 | make_pages_present(addr, addr + len); |
1893 | } |
1894 | return addr; |
1895 | } |
1896 | |
1897 | EXPORT_SYMBOL(do_brk); |
1898 | |
1899 | /* Release all mmaps. */ |
1900 | void exit_mmap(struct mm_struct *mm) |
1901 | { |
1902 | struct mmu_gather *tlb; |
1903 | struct vm_area_struct *vma = mm->mmap; |
1904 | unsigned long nr_accounted = 0; |
1905 | unsigned long end; |
1906 | |
1907 | lru_add_drain(); |
1908 | |
1909 | spin_lock(&mm->page_table_lock); |
1910 | |
1911 | flush_cache_mm(mm); |
1912 | tlb = tlb_gather_mmu(mm, 1); |
1913 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
1914 | end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL); |
1915 | vm_unacct_memory(nr_accounted); |
1916 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
1917 | tlb_finish_mmu(tlb, 0, end); |
1918 | |
1919 | mm->mmap = mm->mmap_cache = NULL; |
1920 | mm->mm_rb = RB_ROOT; |
1921 | set_mm_counter(mm, rss, 0); |
1922 | mm->total_vm = 0; |
1923 | mm->locked_vm = 0; |
1924 | |
1925 | spin_unlock(&mm->page_table_lock); |
1926 | |
1927 | /* |
1928 | * Walk the list again, actually closing and freeing it |
1929 | * without holding any MM locks. |
1930 | */ |
1931 | while (vma) { |
1932 | struct vm_area_struct *next = vma->vm_next; |
1933 | remove_vm_struct(vma); |
1934 | vma = next; |
1935 | } |
1936 | |
1937 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1938 | } |
1939 | |
1940 | /* Insert vm structure into process list sorted by address |
1941 | * and into the inode's i_mmap tree. If vm_file is non-NULL |
1942 | * then i_mmap_lock is taken here. |
1943 | */ |
1944 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
1945 | { |
1946 | struct vm_area_struct * __vma, * prev; |
1947 | struct rb_node ** rb_link, * rb_parent; |
1948 | |
1949 | /* |
1950 | * The vm_pgoff of a purely anonymous vma should be irrelevant |
1951 | * until its first write fault, when page's anon_vma and index |
1952 | * are set. But now set the vm_pgoff it will almost certainly |
1953 | * end up with (unless mremap moves it elsewhere before that |
1954 | * first wfault), so /proc/pid/maps tells a consistent story. |
1955 | * |
1956 | * By setting it to reflect the virtual start address of the |
1957 | * vma, merges and splits can happen in a seamless way, just |
1958 | * using the existing file pgoff checks and manipulations. |
1959 | * Similarly in do_mmap_pgoff and in do_brk. |
1960 | */ |
1961 | if (!vma->vm_file) { |
1962 | BUG_ON(vma->anon_vma); |
1963 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; |
1964 | } |
1965 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); |
1966 | if (__vma && __vma->vm_start < vma->vm_end) |
1967 | return -ENOMEM; |
1968 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1969 | return 0; |
1970 | } |
1971 | |
1972 | /* |
1973 | * Copy the vma structure to a new location in the same mm, |
1974 | * prior to moving page table entries, to effect an mremap move. |
1975 | */ |
1976 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, |
1977 | unsigned long addr, unsigned long len, pgoff_t pgoff) |
1978 | { |
1979 | struct vm_area_struct *vma = *vmap; |
1980 | unsigned long vma_start = vma->vm_start; |
1981 | struct mm_struct *mm = vma->vm_mm; |
1982 | struct vm_area_struct *new_vma, *prev; |
1983 | struct rb_node **rb_link, *rb_parent; |
1984 | struct mempolicy *pol; |
1985 | |
1986 | /* |
1987 | * If anonymous vma has not yet been faulted, update new pgoff |
1988 | * to match new location, to increase its chance of merging. |
1989 | */ |
1990 | if (!vma->vm_file && !vma->anon_vma) |
1991 | pgoff = addr >> PAGE_SHIFT; |
1992 | |
1993 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
1994 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
1995 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); |
1996 | if (new_vma) { |
1997 | /* |
1998 | * Source vma may have been merged into new_vma |
1999 | */ |
2000 | if (vma_start >= new_vma->vm_start && |
2001 | vma_start < new_vma->vm_end) |
2002 | *vmap = new_vma; |
2003 | } else { |
2004 | new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
2005 | if (new_vma) { |
2006 | *new_vma = *vma; |
2007 | pol = mpol_copy(vma_policy(vma)); |
2008 | if (IS_ERR(pol)) { |
2009 | kmem_cache_free(vm_area_cachep, new_vma); |
2010 | return NULL; |
2011 | } |
2012 | vma_set_policy(new_vma, pol); |
2013 | new_vma->vm_start = addr; |
2014 | new_vma->vm_end = addr + len; |
2015 | new_vma->vm_pgoff = pgoff; |
2016 | if (new_vma->vm_file) |
2017 | get_file(new_vma->vm_file); |
2018 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
2019 | new_vma->vm_ops->open(new_vma); |
2020 | vma_link(mm, new_vma, prev, rb_link, rb_parent); |
2021 | } |
2022 | } |
2023 | return new_vma; |
2024 | } |
2025 | |
2026 | /* |
2027 | * Return true if the calling process may expand its vm space by the passed |
2028 | * number of pages |
2029 | */ |
2030 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) |
2031 | { |
2032 | unsigned long cur = mm->total_vm; /* pages */ |
2033 | unsigned long lim; |
2034 | |
2035 | lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; |
2036 | |
2037 | if (cur + npages > lim) |
2038 | return 0; |
2039 | return 1; |
2040 | } |