Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
c59ede7b | 16 | #include <linux/capability.h> |
1da177e4 LT |
17 | #include <linux/init.h> |
18 | #include <linux/file.h> | |
19 | #include <linux/fs.h> | |
20 | #include <linux/personality.h> | |
21 | #include <linux/security.h> | |
22 | #include <linux/hugetlb.h> | |
23 | #include <linux/profile.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/mount.h> | |
26 | #include <linux/mempolicy.h> | |
27 | #include <linux/rmap.h> | |
28 | ||
29 | #include <asm/uaccess.h> | |
30 | #include <asm/cacheflush.h> | |
31 | #include <asm/tlb.h> | |
d6dd61c8 | 32 | #include <asm/mmu_context.h> |
1da177e4 | 33 | |
3a459756 KK |
34 | #ifndef arch_mmap_check |
35 | #define arch_mmap_check(addr, len, flags) (0) | |
36 | #endif | |
37 | ||
e0da382c HD |
38 | static void unmap_region(struct mm_struct *mm, |
39 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
40 | unsigned long start, unsigned long end); | |
41 | ||
1da177e4 LT |
42 | /* |
43 | * WARNING: the debugging will use recursive algorithms so never enable this | |
44 | * unless you know what you are doing. | |
45 | */ | |
46 | #undef DEBUG_MM_RB | |
47 | ||
48 | /* description of effects of mapping type and prot in current implementation. | |
49 | * this is due to the limited x86 page protection hardware. The expected | |
50 | * behavior is in parens: | |
51 | * | |
52 | * map_type prot | |
53 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
54 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
55 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
56 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
57 | * | |
58 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
59 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
60 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
61 | * | |
62 | */ | |
63 | pgprot_t protection_map[16] = { | |
64 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
65 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
66 | }; | |
67 | ||
804af2cf HD |
68 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
69 | { | |
70 | return protection_map[vm_flags & | |
71 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; | |
72 | } | |
73 | EXPORT_SYMBOL(vm_get_page_prot); | |
74 | ||
1da177e4 LT |
75 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
76 | int sysctl_overcommit_ratio = 50; /* default is 50% */ | |
c3d8c141 | 77 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
1da177e4 LT |
78 | atomic_t vm_committed_space = ATOMIC_INIT(0); |
79 | ||
80 | /* | |
81 | * Check that a process has enough memory to allocate a new virtual | |
82 | * mapping. 0 means there is enough memory for the allocation to | |
83 | * succeed and -ENOMEM implies there is not. | |
84 | * | |
85 | * We currently support three overcommit policies, which are set via the | |
86 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
87 | * | |
88 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
89 | * Additional code 2002 Jul 20 by Robert Love. | |
90 | * | |
91 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
92 | * | |
93 | * Note this is a helper function intended to be used by LSMs which | |
94 | * wish to use this logic. | |
95 | */ | |
96 | int __vm_enough_memory(long pages, int cap_sys_admin) | |
97 | { | |
98 | unsigned long free, allowed; | |
99 | ||
100 | vm_acct_memory(pages); | |
101 | ||
102 | /* | |
103 | * Sometimes we want to use more memory than we have | |
104 | */ | |
105 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
106 | return 0; | |
107 | ||
108 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
109 | unsigned long n; | |
110 | ||
347ce434 | 111 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
112 | free += nr_swap_pages; |
113 | ||
114 | /* | |
115 | * Any slabs which are created with the | |
116 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
117 | * which are reclaimable, under pressure. The dentry | |
118 | * cache and most inode caches should fall into this | |
119 | */ | |
972d1a7b | 120 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
121 | |
122 | /* | |
123 | * Leave the last 3% for root | |
124 | */ | |
125 | if (!cap_sys_admin) | |
126 | free -= free / 32; | |
127 | ||
128 | if (free > pages) | |
129 | return 0; | |
130 | ||
131 | /* | |
132 | * nr_free_pages() is very expensive on large systems, | |
133 | * only call if we're about to fail. | |
134 | */ | |
135 | n = nr_free_pages(); | |
6d9f7839 HA |
136 | |
137 | /* | |
138 | * Leave reserved pages. The pages are not for anonymous pages. | |
139 | */ | |
140 | if (n <= totalreserve_pages) | |
141 | goto error; | |
142 | else | |
143 | n -= totalreserve_pages; | |
144 | ||
145 | /* | |
146 | * Leave the last 3% for root | |
147 | */ | |
1da177e4 LT |
148 | if (!cap_sys_admin) |
149 | n -= n / 32; | |
150 | free += n; | |
151 | ||
152 | if (free > pages) | |
153 | return 0; | |
6d9f7839 HA |
154 | |
155 | goto error; | |
1da177e4 LT |
156 | } |
157 | ||
158 | allowed = (totalram_pages - hugetlb_total_pages()) | |
159 | * sysctl_overcommit_ratio / 100; | |
160 | /* | |
161 | * Leave the last 3% for root | |
162 | */ | |
163 | if (!cap_sys_admin) | |
164 | allowed -= allowed / 32; | |
165 | allowed += total_swap_pages; | |
166 | ||
167 | /* Don't let a single process grow too big: | |
168 | leave 3% of the size of this process for other processes */ | |
169 | allowed -= current->mm->total_vm / 32; | |
170 | ||
2f60f8d3 SD |
171 | /* |
172 | * cast `allowed' as a signed long because vm_committed_space | |
173 | * sometimes has a negative value | |
174 | */ | |
175 | if (atomic_read(&vm_committed_space) < (long)allowed) | |
1da177e4 | 176 | return 0; |
6d9f7839 | 177 | error: |
1da177e4 LT |
178 | vm_unacct_memory(pages); |
179 | ||
180 | return -ENOMEM; | |
181 | } | |
182 | ||
1da177e4 LT |
183 | EXPORT_SYMBOL(__vm_enough_memory); |
184 | ||
185 | /* | |
186 | * Requires inode->i_mapping->i_mmap_lock | |
187 | */ | |
188 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
189 | struct file *file, struct address_space *mapping) | |
190 | { | |
191 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 192 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
193 | if (vma->vm_flags & VM_SHARED) |
194 | mapping->i_mmap_writable--; | |
195 | ||
196 | flush_dcache_mmap_lock(mapping); | |
197 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
198 | list_del_init(&vma->shared.vm_set.list); | |
199 | else | |
200 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
201 | flush_dcache_mmap_unlock(mapping); | |
202 | } | |
203 | ||
204 | /* | |
a8fb5618 HD |
205 | * Unlink a file-based vm structure from its prio_tree, to hide |
206 | * vma from rmap and vmtruncate before freeing its page tables. | |
1da177e4 | 207 | */ |
a8fb5618 | 208 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
209 | { |
210 | struct file *file = vma->vm_file; | |
211 | ||
1da177e4 LT |
212 | if (file) { |
213 | struct address_space *mapping = file->f_mapping; | |
214 | spin_lock(&mapping->i_mmap_lock); | |
215 | __remove_shared_vm_struct(vma, file, mapping); | |
216 | spin_unlock(&mapping->i_mmap_lock); | |
217 | } | |
a8fb5618 HD |
218 | } |
219 | ||
220 | /* | |
221 | * Close a vm structure and free it, returning the next. | |
222 | */ | |
223 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
224 | { | |
225 | struct vm_area_struct *next = vma->vm_next; | |
226 | ||
a8fb5618 | 227 | might_sleep(); |
1da177e4 LT |
228 | if (vma->vm_ops && vma->vm_ops->close) |
229 | vma->vm_ops->close(vma); | |
a8fb5618 HD |
230 | if (vma->vm_file) |
231 | fput(vma->vm_file); | |
1da177e4 LT |
232 | mpol_free(vma_policy(vma)); |
233 | kmem_cache_free(vm_area_cachep, vma); | |
a8fb5618 | 234 | return next; |
1da177e4 LT |
235 | } |
236 | ||
1da177e4 LT |
237 | asmlinkage unsigned long sys_brk(unsigned long brk) |
238 | { | |
239 | unsigned long rlim, retval; | |
240 | unsigned long newbrk, oldbrk; | |
241 | struct mm_struct *mm = current->mm; | |
242 | ||
243 | down_write(&mm->mmap_sem); | |
244 | ||
245 | if (brk < mm->end_code) | |
246 | goto out; | |
1e624196 RG |
247 | |
248 | /* | |
249 | * Check against rlimit here. If this check is done later after the test | |
250 | * of oldbrk with newbrk then it can escape the test and let the data | |
251 | * segment grow beyond its set limit the in case where the limit is | |
252 | * not page aligned -Ram Gupta | |
253 | */ | |
254 | rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; | |
255 | if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) | |
256 | goto out; | |
257 | ||
1da177e4 LT |
258 | newbrk = PAGE_ALIGN(brk); |
259 | oldbrk = PAGE_ALIGN(mm->brk); | |
260 | if (oldbrk == newbrk) | |
261 | goto set_brk; | |
262 | ||
263 | /* Always allow shrinking brk. */ | |
264 | if (brk <= mm->brk) { | |
265 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
266 | goto set_brk; | |
267 | goto out; | |
268 | } | |
269 | ||
1da177e4 LT |
270 | /* Check against existing mmap mappings. */ |
271 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
272 | goto out; | |
273 | ||
274 | /* Ok, looks good - let it rip. */ | |
275 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
276 | goto out; | |
277 | set_brk: | |
278 | mm->brk = brk; | |
279 | out: | |
280 | retval = mm->brk; | |
281 | up_write(&mm->mmap_sem); | |
282 | return retval; | |
283 | } | |
284 | ||
285 | #ifdef DEBUG_MM_RB | |
286 | static int browse_rb(struct rb_root *root) | |
287 | { | |
288 | int i = 0, j; | |
289 | struct rb_node *nd, *pn = NULL; | |
290 | unsigned long prev = 0, pend = 0; | |
291 | ||
292 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
293 | struct vm_area_struct *vma; | |
294 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
295 | if (vma->vm_start < prev) | |
296 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
297 | if (vma->vm_start < pend) | |
298 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
299 | if (vma->vm_start > vma->vm_end) | |
300 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
301 | i++; | |
302 | pn = nd; | |
d1af65d1 DM |
303 | prev = vma->vm_start; |
304 | pend = vma->vm_end; | |
1da177e4 LT |
305 | } |
306 | j = 0; | |
307 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
308 | j++; | |
309 | } | |
310 | if (i != j) | |
311 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
312 | return i; | |
313 | } | |
314 | ||
315 | void validate_mm(struct mm_struct *mm) | |
316 | { | |
317 | int bug = 0; | |
318 | int i = 0; | |
319 | struct vm_area_struct *tmp = mm->mmap; | |
320 | while (tmp) { | |
321 | tmp = tmp->vm_next; | |
322 | i++; | |
323 | } | |
324 | if (i != mm->map_count) | |
325 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
326 | i = browse_rb(&mm->mm_rb); | |
327 | if (i != mm->map_count) | |
328 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 329 | BUG_ON(bug); |
1da177e4 LT |
330 | } |
331 | #else | |
332 | #define validate_mm(mm) do { } while (0) | |
333 | #endif | |
334 | ||
335 | static struct vm_area_struct * | |
336 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, | |
337 | struct vm_area_struct **pprev, struct rb_node ***rb_link, | |
338 | struct rb_node ** rb_parent) | |
339 | { | |
340 | struct vm_area_struct * vma; | |
341 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; | |
342 | ||
343 | __rb_link = &mm->mm_rb.rb_node; | |
344 | rb_prev = __rb_parent = NULL; | |
345 | vma = NULL; | |
346 | ||
347 | while (*__rb_link) { | |
348 | struct vm_area_struct *vma_tmp; | |
349 | ||
350 | __rb_parent = *__rb_link; | |
351 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
352 | ||
353 | if (vma_tmp->vm_end > addr) { | |
354 | vma = vma_tmp; | |
355 | if (vma_tmp->vm_start <= addr) | |
356 | return vma; | |
357 | __rb_link = &__rb_parent->rb_left; | |
358 | } else { | |
359 | rb_prev = __rb_parent; | |
360 | __rb_link = &__rb_parent->rb_right; | |
361 | } | |
362 | } | |
363 | ||
364 | *pprev = NULL; | |
365 | if (rb_prev) | |
366 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
367 | *rb_link = __rb_link; | |
368 | *rb_parent = __rb_parent; | |
369 | return vma; | |
370 | } | |
371 | ||
372 | static inline void | |
373 | __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, | |
374 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
375 | { | |
376 | if (prev) { | |
377 | vma->vm_next = prev->vm_next; | |
378 | prev->vm_next = vma; | |
379 | } else { | |
380 | mm->mmap = vma; | |
381 | if (rb_parent) | |
382 | vma->vm_next = rb_entry(rb_parent, | |
383 | struct vm_area_struct, vm_rb); | |
384 | else | |
385 | vma->vm_next = NULL; | |
386 | } | |
387 | } | |
388 | ||
389 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, | |
390 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
391 | { | |
392 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
393 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
394 | } | |
395 | ||
396 | static inline void __vma_link_file(struct vm_area_struct *vma) | |
397 | { | |
398 | struct file * file; | |
399 | ||
400 | file = vma->vm_file; | |
401 | if (file) { | |
402 | struct address_space *mapping = file->f_mapping; | |
403 | ||
404 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 405 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
406 | if (vma->vm_flags & VM_SHARED) |
407 | mapping->i_mmap_writable++; | |
408 | ||
409 | flush_dcache_mmap_lock(mapping); | |
410 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
411 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
412 | else | |
413 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
414 | flush_dcache_mmap_unlock(mapping); | |
415 | } | |
416 | } | |
417 | ||
418 | static void | |
419 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
420 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
421 | struct rb_node *rb_parent) | |
422 | { | |
423 | __vma_link_list(mm, vma, prev, rb_parent); | |
424 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
425 | __anon_vma_link(vma); | |
426 | } | |
427 | ||
428 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
429 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
430 | struct rb_node *rb_parent) | |
431 | { | |
432 | struct address_space *mapping = NULL; | |
433 | ||
434 | if (vma->vm_file) | |
435 | mapping = vma->vm_file->f_mapping; | |
436 | ||
437 | if (mapping) { | |
438 | spin_lock(&mapping->i_mmap_lock); | |
439 | vma->vm_truncate_count = mapping->truncate_count; | |
440 | } | |
441 | anon_vma_lock(vma); | |
442 | ||
443 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
444 | __vma_link_file(vma); | |
445 | ||
446 | anon_vma_unlock(vma); | |
447 | if (mapping) | |
448 | spin_unlock(&mapping->i_mmap_lock); | |
449 | ||
450 | mm->map_count++; | |
451 | validate_mm(mm); | |
452 | } | |
453 | ||
454 | /* | |
455 | * Helper for vma_adjust in the split_vma insert case: | |
456 | * insert vm structure into list and rbtree and anon_vma, | |
457 | * but it has already been inserted into prio_tree earlier. | |
458 | */ | |
459 | static void | |
460 | __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
461 | { | |
462 | struct vm_area_struct * __vma, * prev; | |
463 | struct rb_node ** rb_link, * rb_parent; | |
464 | ||
465 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); | |
46a350ef | 466 | BUG_ON(__vma && __vma->vm_start < vma->vm_end); |
1da177e4 LT |
467 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
468 | mm->map_count++; | |
469 | } | |
470 | ||
471 | static inline void | |
472 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
473 | struct vm_area_struct *prev) | |
474 | { | |
475 | prev->vm_next = vma->vm_next; | |
476 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
477 | if (mm->mmap_cache == vma) | |
478 | mm->mmap_cache = prev; | |
479 | } | |
480 | ||
481 | /* | |
482 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
483 | * is already present in an i_mmap tree without adjusting the tree. | |
484 | * The following helper function should be used when such adjustments | |
485 | * are necessary. The "insert" vma (if any) is to be inserted | |
486 | * before we drop the necessary locks. | |
487 | */ | |
488 | void vma_adjust(struct vm_area_struct *vma, unsigned long start, | |
489 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) | |
490 | { | |
491 | struct mm_struct *mm = vma->vm_mm; | |
492 | struct vm_area_struct *next = vma->vm_next; | |
493 | struct vm_area_struct *importer = NULL; | |
494 | struct address_space *mapping = NULL; | |
495 | struct prio_tree_root *root = NULL; | |
496 | struct file *file = vma->vm_file; | |
497 | struct anon_vma *anon_vma = NULL; | |
498 | long adjust_next = 0; | |
499 | int remove_next = 0; | |
500 | ||
501 | if (next && !insert) { | |
502 | if (end >= next->vm_end) { | |
503 | /* | |
504 | * vma expands, overlapping all the next, and | |
505 | * perhaps the one after too (mprotect case 6). | |
506 | */ | |
507 | again: remove_next = 1 + (end > next->vm_end); | |
508 | end = next->vm_end; | |
509 | anon_vma = next->anon_vma; | |
510 | importer = vma; | |
511 | } else if (end > next->vm_start) { | |
512 | /* | |
513 | * vma expands, overlapping part of the next: | |
514 | * mprotect case 5 shifting the boundary up. | |
515 | */ | |
516 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
517 | anon_vma = next->anon_vma; | |
518 | importer = vma; | |
519 | } else if (end < vma->vm_end) { | |
520 | /* | |
521 | * vma shrinks, and !insert tells it's not | |
522 | * split_vma inserting another: so it must be | |
523 | * mprotect case 4 shifting the boundary down. | |
524 | */ | |
525 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
526 | anon_vma = next->anon_vma; | |
527 | importer = next; | |
528 | } | |
529 | } | |
530 | ||
531 | if (file) { | |
532 | mapping = file->f_mapping; | |
533 | if (!(vma->vm_flags & VM_NONLINEAR)) | |
534 | root = &mapping->i_mmap; | |
535 | spin_lock(&mapping->i_mmap_lock); | |
536 | if (importer && | |
537 | vma->vm_truncate_count != next->vm_truncate_count) { | |
538 | /* | |
539 | * unmap_mapping_range might be in progress: | |
540 | * ensure that the expanding vma is rescanned. | |
541 | */ | |
542 | importer->vm_truncate_count = 0; | |
543 | } | |
544 | if (insert) { | |
545 | insert->vm_truncate_count = vma->vm_truncate_count; | |
546 | /* | |
547 | * Put into prio_tree now, so instantiated pages | |
548 | * are visible to arm/parisc __flush_dcache_page | |
549 | * throughout; but we cannot insert into address | |
550 | * space until vma start or end is updated. | |
551 | */ | |
552 | __vma_link_file(insert); | |
553 | } | |
554 | } | |
555 | ||
556 | /* | |
557 | * When changing only vma->vm_end, we don't really need | |
558 | * anon_vma lock: but is that case worth optimizing out? | |
559 | */ | |
560 | if (vma->anon_vma) | |
561 | anon_vma = vma->anon_vma; | |
562 | if (anon_vma) { | |
563 | spin_lock(&anon_vma->lock); | |
564 | /* | |
565 | * Easily overlooked: when mprotect shifts the boundary, | |
566 | * make sure the expanding vma has anon_vma set if the | |
567 | * shrinking vma had, to cover any anon pages imported. | |
568 | */ | |
569 | if (importer && !importer->anon_vma) { | |
570 | importer->anon_vma = anon_vma; | |
571 | __anon_vma_link(importer); | |
572 | } | |
573 | } | |
574 | ||
575 | if (root) { | |
576 | flush_dcache_mmap_lock(mapping); | |
577 | vma_prio_tree_remove(vma, root); | |
578 | if (adjust_next) | |
579 | vma_prio_tree_remove(next, root); | |
580 | } | |
581 | ||
582 | vma->vm_start = start; | |
583 | vma->vm_end = end; | |
584 | vma->vm_pgoff = pgoff; | |
585 | if (adjust_next) { | |
586 | next->vm_start += adjust_next << PAGE_SHIFT; | |
587 | next->vm_pgoff += adjust_next; | |
588 | } | |
589 | ||
590 | if (root) { | |
591 | if (adjust_next) | |
592 | vma_prio_tree_insert(next, root); | |
593 | vma_prio_tree_insert(vma, root); | |
594 | flush_dcache_mmap_unlock(mapping); | |
595 | } | |
596 | ||
597 | if (remove_next) { | |
598 | /* | |
599 | * vma_merge has merged next into vma, and needs | |
600 | * us to remove next before dropping the locks. | |
601 | */ | |
602 | __vma_unlink(mm, next, vma); | |
603 | if (file) | |
604 | __remove_shared_vm_struct(next, file, mapping); | |
605 | if (next->anon_vma) | |
606 | __anon_vma_merge(vma, next); | |
607 | } else if (insert) { | |
608 | /* | |
609 | * split_vma has split insert from vma, and needs | |
610 | * us to insert it before dropping the locks | |
611 | * (it may either follow vma or precede it). | |
612 | */ | |
613 | __insert_vm_struct(mm, insert); | |
614 | } | |
615 | ||
616 | if (anon_vma) | |
617 | spin_unlock(&anon_vma->lock); | |
618 | if (mapping) | |
619 | spin_unlock(&mapping->i_mmap_lock); | |
620 | ||
621 | if (remove_next) { | |
622 | if (file) | |
623 | fput(file); | |
624 | mm->map_count--; | |
625 | mpol_free(vma_policy(next)); | |
626 | kmem_cache_free(vm_area_cachep, next); | |
627 | /* | |
628 | * In mprotect's case 6 (see comments on vma_merge), | |
629 | * we must remove another next too. It would clutter | |
630 | * up the code too much to do both in one go. | |
631 | */ | |
632 | if (remove_next == 2) { | |
633 | next = vma->vm_next; | |
634 | goto again; | |
635 | } | |
636 | } | |
637 | ||
638 | validate_mm(mm); | |
639 | } | |
640 | ||
641 | /* | |
642 | * If the vma has a ->close operation then the driver probably needs to release | |
643 | * per-vma resources, so we don't attempt to merge those. | |
644 | */ | |
a6f563db | 645 | #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) |
1da177e4 LT |
646 | |
647 | static inline int is_mergeable_vma(struct vm_area_struct *vma, | |
648 | struct file *file, unsigned long vm_flags) | |
649 | { | |
650 | if (vma->vm_flags != vm_flags) | |
651 | return 0; | |
652 | if (vma->vm_file != file) | |
653 | return 0; | |
654 | if (vma->vm_ops && vma->vm_ops->close) | |
655 | return 0; | |
656 | return 1; | |
657 | } | |
658 | ||
659 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
660 | struct anon_vma *anon_vma2) | |
661 | { | |
662 | return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); | |
663 | } | |
664 | ||
665 | /* | |
666 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
667 | * in front of (at a lower virtual address and file offset than) the vma. | |
668 | * | |
669 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
670 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
671 | * | |
672 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
673 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
674 | * wrap, nor mmaps which cover the final page at index -1UL. | |
675 | */ | |
676 | static int | |
677 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
678 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
679 | { | |
680 | if (is_mergeable_vma(vma, file, vm_flags) && | |
681 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
682 | if (vma->vm_pgoff == vm_pgoff) | |
683 | return 1; | |
684 | } | |
685 | return 0; | |
686 | } | |
687 | ||
688 | /* | |
689 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
690 | * beyond (at a higher virtual address and file offset than) the vma. | |
691 | * | |
692 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
693 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
694 | */ | |
695 | static int | |
696 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
697 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
698 | { | |
699 | if (is_mergeable_vma(vma, file, vm_flags) && | |
700 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
701 | pgoff_t vm_pglen; | |
702 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
703 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
704 | return 1; | |
705 | } | |
706 | return 0; | |
707 | } | |
708 | ||
709 | /* | |
710 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
711 | * whether that can be merged with its predecessor or its successor. | |
712 | * Or both (it neatly fills a hole). | |
713 | * | |
714 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
715 | * certain not to be mapped by the time vma_merge is called; but when | |
716 | * called for mprotect, it is certain to be already mapped (either at | |
717 | * an offset within prev, or at the start of next), and the flags of | |
718 | * this area are about to be changed to vm_flags - and the no-change | |
719 | * case has already been eliminated. | |
720 | * | |
721 | * The following mprotect cases have to be considered, where AAAA is | |
722 | * the area passed down from mprotect_fixup, never extending beyond one | |
723 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
724 | * | |
725 | * AAAA AAAA AAAA AAAA | |
726 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
727 | * cannot merge might become might become might become | |
728 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
729 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
730 | * mremap move: PPPPNNNNNNNN 8 | |
731 | * AAAA | |
732 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
733 | * might become case 1 below case 2 below case 3 below | |
734 | * | |
735 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
736 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
737 | */ | |
738 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
739 | struct vm_area_struct *prev, unsigned long addr, | |
740 | unsigned long end, unsigned long vm_flags, | |
741 | struct anon_vma *anon_vma, struct file *file, | |
742 | pgoff_t pgoff, struct mempolicy *policy) | |
743 | { | |
744 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
745 | struct vm_area_struct *area, *next; | |
746 | ||
747 | /* | |
748 | * We later require that vma->vm_flags == vm_flags, | |
749 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
750 | */ | |
751 | if (vm_flags & VM_SPECIAL) | |
752 | return NULL; | |
753 | ||
754 | if (prev) | |
755 | next = prev->vm_next; | |
756 | else | |
757 | next = mm->mmap; | |
758 | area = next; | |
759 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
760 | next = next->vm_next; | |
761 | ||
762 | /* | |
763 | * Can it merge with the predecessor? | |
764 | */ | |
765 | if (prev && prev->vm_end == addr && | |
766 | mpol_equal(vma_policy(prev), policy) && | |
767 | can_vma_merge_after(prev, vm_flags, | |
768 | anon_vma, file, pgoff)) { | |
769 | /* | |
770 | * OK, it can. Can we now merge in the successor as well? | |
771 | */ | |
772 | if (next && end == next->vm_start && | |
773 | mpol_equal(policy, vma_policy(next)) && | |
774 | can_vma_merge_before(next, vm_flags, | |
775 | anon_vma, file, pgoff+pglen) && | |
776 | is_mergeable_anon_vma(prev->anon_vma, | |
777 | next->anon_vma)) { | |
778 | /* cases 1, 6 */ | |
779 | vma_adjust(prev, prev->vm_start, | |
780 | next->vm_end, prev->vm_pgoff, NULL); | |
781 | } else /* cases 2, 5, 7 */ | |
782 | vma_adjust(prev, prev->vm_start, | |
783 | end, prev->vm_pgoff, NULL); | |
784 | return prev; | |
785 | } | |
786 | ||
787 | /* | |
788 | * Can this new request be merged in front of next? | |
789 | */ | |
790 | if (next && end == next->vm_start && | |
791 | mpol_equal(policy, vma_policy(next)) && | |
792 | can_vma_merge_before(next, vm_flags, | |
793 | anon_vma, file, pgoff+pglen)) { | |
794 | if (prev && addr < prev->vm_end) /* case 4 */ | |
795 | vma_adjust(prev, prev->vm_start, | |
796 | addr, prev->vm_pgoff, NULL); | |
797 | else /* cases 3, 8 */ | |
798 | vma_adjust(area, addr, next->vm_end, | |
799 | next->vm_pgoff - pglen, NULL); | |
800 | return area; | |
801 | } | |
802 | ||
803 | return NULL; | |
804 | } | |
805 | ||
806 | /* | |
807 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
808 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
809 | * to allocate a new anon_vma. It checks because a repetitive | |
810 | * sequence of mprotects and faults may otherwise lead to distinct | |
811 | * anon_vmas being allocated, preventing vma merge in subsequent | |
812 | * mprotect. | |
813 | */ | |
814 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
815 | { | |
816 | struct vm_area_struct *near; | |
817 | unsigned long vm_flags; | |
818 | ||
819 | near = vma->vm_next; | |
820 | if (!near) | |
821 | goto try_prev; | |
822 | ||
823 | /* | |
824 | * Since only mprotect tries to remerge vmas, match flags | |
825 | * which might be mprotected into each other later on. | |
826 | * Neither mlock nor madvise tries to remerge at present, | |
827 | * so leave their flags as obstructing a merge. | |
828 | */ | |
829 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
830 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
831 | ||
832 | if (near->anon_vma && vma->vm_end == near->vm_start && | |
833 | mpol_equal(vma_policy(vma), vma_policy(near)) && | |
834 | can_vma_merge_before(near, vm_flags, | |
835 | NULL, vma->vm_file, vma->vm_pgoff + | |
836 | ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) | |
837 | return near->anon_vma; | |
838 | try_prev: | |
839 | /* | |
840 | * It is potentially slow to have to call find_vma_prev here. | |
841 | * But it's only on the first write fault on the vma, not | |
842 | * every time, and we could devise a way to avoid it later | |
843 | * (e.g. stash info in next's anon_vma_node when assigning | |
844 | * an anon_vma, or when trying vma_merge). Another time. | |
845 | */ | |
46a350ef | 846 | BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma); |
1da177e4 LT |
847 | if (!near) |
848 | goto none; | |
849 | ||
850 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
851 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
852 | ||
853 | if (near->anon_vma && near->vm_end == vma->vm_start && | |
854 | mpol_equal(vma_policy(near), vma_policy(vma)) && | |
855 | can_vma_merge_after(near, vm_flags, | |
856 | NULL, vma->vm_file, vma->vm_pgoff)) | |
857 | return near->anon_vma; | |
858 | none: | |
859 | /* | |
860 | * There's no absolute need to look only at touching neighbours: | |
861 | * we could search further afield for "compatible" anon_vmas. | |
862 | * But it would probably just be a waste of time searching, | |
863 | * or lead to too many vmas hanging off the same anon_vma. | |
864 | * We're trying to allow mprotect remerging later on, | |
865 | * not trying to minimize memory used for anon_vmas. | |
866 | */ | |
867 | return NULL; | |
868 | } | |
869 | ||
870 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 871 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
872 | struct file *file, long pages) |
873 | { | |
874 | const unsigned long stack_flags | |
875 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
876 | ||
1da177e4 LT |
877 | if (file) { |
878 | mm->shared_vm += pages; | |
879 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
880 | mm->exec_vm += pages; | |
881 | } else if (flags & stack_flags) | |
882 | mm->stack_vm += pages; | |
883 | if (flags & (VM_RESERVED|VM_IO)) | |
884 | mm->reserved_vm += pages; | |
885 | } | |
886 | #endif /* CONFIG_PROC_FS */ | |
887 | ||
888 | /* | |
889 | * The caller must hold down_write(current->mm->mmap_sem). | |
890 | */ | |
891 | ||
892 | unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, | |
893 | unsigned long len, unsigned long prot, | |
894 | unsigned long flags, unsigned long pgoff) | |
895 | { | |
896 | struct mm_struct * mm = current->mm; | |
897 | struct vm_area_struct * vma, * prev; | |
898 | struct inode *inode; | |
899 | unsigned int vm_flags; | |
900 | int correct_wcount = 0; | |
901 | int error; | |
902 | struct rb_node ** rb_link, * rb_parent; | |
903 | int accountable = 1; | |
904 | unsigned long charged = 0, reqprot = prot; | |
905 | ||
1da177e4 LT |
906 | /* |
907 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
908 | * | |
909 | * (the exception is when the underlying filesystem is noexec | |
910 | * mounted, in which case we dont add PROT_EXEC.) | |
911 | */ | |
912 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 913 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
914 | prot |= PROT_EXEC; |
915 | ||
916 | if (!len) | |
917 | return -EINVAL; | |
918 | ||
3a459756 KK |
919 | error = arch_mmap_check(addr, len, flags); |
920 | if (error) | |
921 | return error; | |
922 | ||
1da177e4 LT |
923 | /* Careful about overflows.. */ |
924 | len = PAGE_ALIGN(len); | |
925 | if (!len || len > TASK_SIZE) | |
926 | return -ENOMEM; | |
927 | ||
928 | /* offset overflow? */ | |
929 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
930 | return -EOVERFLOW; | |
931 | ||
932 | /* Too many mappings? */ | |
933 | if (mm->map_count > sysctl_max_map_count) | |
934 | return -ENOMEM; | |
935 | ||
936 | /* Obtain the address to map to. we verify (or select) it and ensure | |
937 | * that it represents a valid section of the address space. | |
938 | */ | |
939 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
940 | if (addr & ~PAGE_MASK) | |
941 | return addr; | |
942 | ||
943 | /* Do simple checking here so the lower-level routines won't have | |
944 | * to. we assume access permissions have been handled by the open | |
945 | * of the memory object, so we don't do any here. | |
946 | */ | |
947 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
948 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
949 | ||
950 | if (flags & MAP_LOCKED) { | |
951 | if (!can_do_mlock()) | |
952 | return -EPERM; | |
953 | vm_flags |= VM_LOCKED; | |
954 | } | |
955 | /* mlock MCL_FUTURE? */ | |
956 | if (vm_flags & VM_LOCKED) { | |
957 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
958 | locked = len >> PAGE_SHIFT; |
959 | locked += mm->locked_vm; | |
1da177e4 | 960 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 961 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
962 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
963 | return -EAGAIN; | |
964 | } | |
965 | ||
d3ac7f89 | 966 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
967 | |
968 | if (file) { | |
969 | switch (flags & MAP_TYPE) { | |
970 | case MAP_SHARED: | |
971 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
972 | return -EACCES; | |
973 | ||
974 | /* | |
975 | * Make sure we don't allow writing to an append-only | |
976 | * file.. | |
977 | */ | |
978 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
979 | return -EACCES; | |
980 | ||
981 | /* | |
982 | * Make sure there are no mandatory locks on the file. | |
983 | */ | |
984 | if (locks_verify_locked(inode)) | |
985 | return -EAGAIN; | |
986 | ||
987 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
988 | if (!(file->f_mode & FMODE_WRITE)) | |
989 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
990 | ||
991 | /* fall through */ | |
992 | case MAP_PRIVATE: | |
993 | if (!(file->f_mode & FMODE_READ)) | |
994 | return -EACCES; | |
d3ac7f89 | 995 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
996 | if (vm_flags & VM_EXEC) |
997 | return -EPERM; | |
998 | vm_flags &= ~VM_MAYEXEC; | |
999 | } | |
1000 | if (is_file_hugepages(file)) | |
1001 | accountable = 0; | |
1002 | ||
1003 | if (!file->f_op || !file->f_op->mmap) | |
1004 | return -ENODEV; | |
1da177e4 LT |
1005 | break; |
1006 | ||
1007 | default: | |
1008 | return -EINVAL; | |
1009 | } | |
1010 | } else { | |
1011 | switch (flags & MAP_TYPE) { | |
1012 | case MAP_SHARED: | |
1013 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1014 | break; | |
1015 | case MAP_PRIVATE: | |
1016 | /* | |
1017 | * Set pgoff according to addr for anon_vma. | |
1018 | */ | |
1019 | pgoff = addr >> PAGE_SHIFT; | |
1020 | break; | |
1021 | default: | |
1022 | return -EINVAL; | |
1023 | } | |
1024 | } | |
1025 | ||
1026 | error = security_file_mmap(file, reqprot, prot, flags); | |
1027 | if (error) | |
1028 | return error; | |
1029 | ||
1030 | /* Clear old maps */ | |
1031 | error = -ENOMEM; | |
1032 | munmap_back: | |
1033 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1034 | if (vma && vma->vm_start < addr + len) { | |
1035 | if (do_munmap(mm, addr, len)) | |
1036 | return -ENOMEM; | |
1037 | goto munmap_back; | |
1038 | } | |
1039 | ||
1040 | /* Check against address space limit. */ | |
119f657c | 1041 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1042 | return -ENOMEM; |
1043 | ||
1044 | if (accountable && (!(flags & MAP_NORESERVE) || | |
1045 | sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { | |
1046 | if (vm_flags & VM_SHARED) { | |
1047 | /* Check memory availability in shmem_file_setup? */ | |
1048 | vm_flags |= VM_ACCOUNT; | |
1049 | } else if (vm_flags & VM_WRITE) { | |
1050 | /* | |
1051 | * Private writable mapping: check memory availability | |
1052 | */ | |
1053 | charged = len >> PAGE_SHIFT; | |
1054 | if (security_vm_enough_memory(charged)) | |
1055 | return -ENOMEM; | |
1056 | vm_flags |= VM_ACCOUNT; | |
1057 | } | |
1058 | } | |
1059 | ||
1060 | /* | |
1061 | * Can we just expand an old private anonymous mapping? | |
1062 | * The VM_SHARED test is necessary because shmem_zero_setup | |
1063 | * will create the file object for a shared anonymous map below. | |
1064 | */ | |
1065 | if (!file && !(vm_flags & VM_SHARED) && | |
1066 | vma_merge(mm, prev, addr, addr + len, vm_flags, | |
1067 | NULL, NULL, pgoff, NULL)) | |
1068 | goto out; | |
1069 | ||
1070 | /* | |
1071 | * Determine the object being mapped and call the appropriate | |
1072 | * specific mapper. the address has already been validated, but | |
1073 | * not unmapped, but the maps are removed from the list. | |
1074 | */ | |
c5e3b83e | 1075 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1076 | if (!vma) { |
1077 | error = -ENOMEM; | |
1078 | goto unacct_error; | |
1079 | } | |
1da177e4 LT |
1080 | |
1081 | vma->vm_mm = mm; | |
1082 | vma->vm_start = addr; | |
1083 | vma->vm_end = addr + len; | |
1084 | vma->vm_flags = vm_flags; | |
9637a5ef DH |
1085 | vma->vm_page_prot = protection_map[vm_flags & |
1086 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; | |
1da177e4 LT |
1087 | vma->vm_pgoff = pgoff; |
1088 | ||
1089 | if (file) { | |
1090 | error = -EINVAL; | |
1091 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) | |
1092 | goto free_vma; | |
1093 | if (vm_flags & VM_DENYWRITE) { | |
1094 | error = deny_write_access(file); | |
1095 | if (error) | |
1096 | goto free_vma; | |
1097 | correct_wcount = 1; | |
1098 | } | |
1099 | vma->vm_file = file; | |
1100 | get_file(file); | |
1101 | error = file->f_op->mmap(file, vma); | |
1102 | if (error) | |
1103 | goto unmap_and_free_vma; | |
1104 | } else if (vm_flags & VM_SHARED) { | |
1105 | error = shmem_zero_setup(vma); | |
1106 | if (error) | |
1107 | goto free_vma; | |
1108 | } | |
1109 | ||
1110 | /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform | |
1111 | * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) | |
1112 | * that memory reservation must be checked; but that reservation | |
1113 | * belongs to shared memory object, not to vma: so now clear it. | |
1114 | */ | |
1115 | if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) | |
1116 | vma->vm_flags &= ~VM_ACCOUNT; | |
1117 | ||
1118 | /* Can addr have changed?? | |
1119 | * | |
1120 | * Answer: Yes, several device drivers can do it in their | |
1121 | * f_op->mmap method. -DaveM | |
1122 | */ | |
1123 | addr = vma->vm_start; | |
1124 | pgoff = vma->vm_pgoff; | |
1125 | vm_flags = vma->vm_flags; | |
1126 | ||
d08b3851 PZ |
1127 | if (vma_wants_writenotify(vma)) |
1128 | vma->vm_page_prot = | |
1129 | protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)]; | |
1130 | ||
1da177e4 LT |
1131 | if (!file || !vma_merge(mm, prev, addr, vma->vm_end, |
1132 | vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { | |
1133 | file = vma->vm_file; | |
1134 | vma_link(mm, vma, prev, rb_link, rb_parent); | |
1135 | if (correct_wcount) | |
1136 | atomic_inc(&inode->i_writecount); | |
1137 | } else { | |
1138 | if (file) { | |
1139 | if (correct_wcount) | |
1140 | atomic_inc(&inode->i_writecount); | |
1141 | fput(file); | |
1142 | } | |
1143 | mpol_free(vma_policy(vma)); | |
1144 | kmem_cache_free(vm_area_cachep, vma); | |
1145 | } | |
1146 | out: | |
1147 | mm->total_vm += len >> PAGE_SHIFT; | |
ab50b8ed | 1148 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 LT |
1149 | if (vm_flags & VM_LOCKED) { |
1150 | mm->locked_vm += len >> PAGE_SHIFT; | |
1151 | make_pages_present(addr, addr + len); | |
1152 | } | |
1153 | if (flags & MAP_POPULATE) { | |
1154 | up_write(&mm->mmap_sem); | |
1155 | sys_remap_file_pages(addr, len, 0, | |
1156 | pgoff, flags & MAP_NONBLOCK); | |
1157 | down_write(&mm->mmap_sem); | |
1158 | } | |
1159 | return addr; | |
1160 | ||
1161 | unmap_and_free_vma: | |
1162 | if (correct_wcount) | |
1163 | atomic_inc(&inode->i_writecount); | |
1164 | vma->vm_file = NULL; | |
1165 | fput(file); | |
1166 | ||
1167 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1168 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1169 | charged = 0; | |
1da177e4 LT |
1170 | free_vma: |
1171 | kmem_cache_free(vm_area_cachep, vma); | |
1172 | unacct_error: | |
1173 | if (charged) | |
1174 | vm_unacct_memory(charged); | |
1175 | return error; | |
1176 | } | |
1177 | ||
1178 | EXPORT_SYMBOL(do_mmap_pgoff); | |
1179 | ||
1180 | /* Get an address range which is currently unmapped. | |
1181 | * For shmat() with addr=0. | |
1182 | * | |
1183 | * Ugly calling convention alert: | |
1184 | * Return value with the low bits set means error value, | |
1185 | * ie | |
1186 | * if (ret & ~PAGE_MASK) | |
1187 | * error = ret; | |
1188 | * | |
1189 | * This function "knows" that -ENOMEM has the bits set. | |
1190 | */ | |
1191 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1192 | unsigned long | |
1193 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1194 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1195 | { | |
1196 | struct mm_struct *mm = current->mm; | |
1197 | struct vm_area_struct *vma; | |
1198 | unsigned long start_addr; | |
1199 | ||
1200 | if (len > TASK_SIZE) | |
1201 | return -ENOMEM; | |
1202 | ||
06abdfb4 BH |
1203 | if (flags & MAP_FIXED) |
1204 | return addr; | |
1205 | ||
1da177e4 LT |
1206 | if (addr) { |
1207 | addr = PAGE_ALIGN(addr); | |
1208 | vma = find_vma(mm, addr); | |
1209 | if (TASK_SIZE - len >= addr && | |
1210 | (!vma || addr + len <= vma->vm_start)) | |
1211 | return addr; | |
1212 | } | |
1363c3cd WW |
1213 | if (len > mm->cached_hole_size) { |
1214 | start_addr = addr = mm->free_area_cache; | |
1215 | } else { | |
1216 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1217 | mm->cached_hole_size = 0; | |
1218 | } | |
1da177e4 LT |
1219 | |
1220 | full_search: | |
1221 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1222 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1223 | if (TASK_SIZE - len < addr) { | |
1224 | /* | |
1225 | * Start a new search - just in case we missed | |
1226 | * some holes. | |
1227 | */ | |
1228 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1229 | addr = TASK_UNMAPPED_BASE; |
1230 | start_addr = addr; | |
1231 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1232 | goto full_search; |
1233 | } | |
1234 | return -ENOMEM; | |
1235 | } | |
1236 | if (!vma || addr + len <= vma->vm_start) { | |
1237 | /* | |
1238 | * Remember the place where we stopped the search: | |
1239 | */ | |
1240 | mm->free_area_cache = addr + len; | |
1241 | return addr; | |
1242 | } | |
1363c3cd WW |
1243 | if (addr + mm->cached_hole_size < vma->vm_start) |
1244 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1245 | addr = vma->vm_end; |
1246 | } | |
1247 | } | |
1248 | #endif | |
1249 | ||
1363c3cd | 1250 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1251 | { |
1252 | /* | |
1253 | * Is this a new hole at the lowest possible address? | |
1254 | */ | |
1363c3cd WW |
1255 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { |
1256 | mm->free_area_cache = addr; | |
1257 | mm->cached_hole_size = ~0UL; | |
1258 | } | |
1da177e4 LT |
1259 | } |
1260 | ||
1261 | /* | |
1262 | * This mmap-allocator allocates new areas top-down from below the | |
1263 | * stack's low limit (the base): | |
1264 | */ | |
1265 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1266 | unsigned long | |
1267 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1268 | const unsigned long len, const unsigned long pgoff, | |
1269 | const unsigned long flags) | |
1270 | { | |
1271 | struct vm_area_struct *vma; | |
1272 | struct mm_struct *mm = current->mm; | |
1273 | unsigned long addr = addr0; | |
1274 | ||
1275 | /* requested length too big for entire address space */ | |
1276 | if (len > TASK_SIZE) | |
1277 | return -ENOMEM; | |
1278 | ||
06abdfb4 BH |
1279 | if (flags & MAP_FIXED) |
1280 | return addr; | |
1281 | ||
1da177e4 LT |
1282 | /* requesting a specific address */ |
1283 | if (addr) { | |
1284 | addr = PAGE_ALIGN(addr); | |
1285 | vma = find_vma(mm, addr); | |
1286 | if (TASK_SIZE - len >= addr && | |
1287 | (!vma || addr + len <= vma->vm_start)) | |
1288 | return addr; | |
1289 | } | |
1290 | ||
1363c3cd WW |
1291 | /* check if free_area_cache is useful for us */ |
1292 | if (len <= mm->cached_hole_size) { | |
1293 | mm->cached_hole_size = 0; | |
1294 | mm->free_area_cache = mm->mmap_base; | |
1295 | } | |
1296 | ||
1da177e4 LT |
1297 | /* either no address requested or can't fit in requested address hole */ |
1298 | addr = mm->free_area_cache; | |
1299 | ||
1300 | /* make sure it can fit in the remaining address space */ | |
49a43876 | 1301 | if (addr > len) { |
1da177e4 LT |
1302 | vma = find_vma(mm, addr-len); |
1303 | if (!vma || addr <= vma->vm_start) | |
1304 | /* remember the address as a hint for next time */ | |
1305 | return (mm->free_area_cache = addr-len); | |
1306 | } | |
1307 | ||
73219d17 CW |
1308 | if (mm->mmap_base < len) |
1309 | goto bottomup; | |
1310 | ||
1da177e4 LT |
1311 | addr = mm->mmap_base-len; |
1312 | ||
1313 | do { | |
1314 | /* | |
1315 | * Lookup failure means no vma is above this address, | |
1316 | * else if new region fits below vma->vm_start, | |
1317 | * return with success: | |
1318 | */ | |
1319 | vma = find_vma(mm, addr); | |
1320 | if (!vma || addr+len <= vma->vm_start) | |
1321 | /* remember the address as a hint for next time */ | |
1322 | return (mm->free_area_cache = addr); | |
1323 | ||
1363c3cd WW |
1324 | /* remember the largest hole we saw so far */ |
1325 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1326 | mm->cached_hole_size = vma->vm_start - addr; | |
1327 | ||
1da177e4 LT |
1328 | /* try just below the current vma->vm_start */ |
1329 | addr = vma->vm_start-len; | |
49a43876 | 1330 | } while (len < vma->vm_start); |
1da177e4 | 1331 | |
73219d17 | 1332 | bottomup: |
1da177e4 LT |
1333 | /* |
1334 | * A failed mmap() very likely causes application failure, | |
1335 | * so fall back to the bottom-up function here. This scenario | |
1336 | * can happen with large stack limits and large mmap() | |
1337 | * allocations. | |
1338 | */ | |
1363c3cd WW |
1339 | mm->cached_hole_size = ~0UL; |
1340 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1341 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1342 | /* | |
1343 | * Restore the topdown base: | |
1344 | */ | |
1345 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1346 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1347 | |
1348 | return addr; | |
1349 | } | |
1350 | #endif | |
1351 | ||
1363c3cd | 1352 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1353 | { |
1354 | /* | |
1355 | * Is this a new hole at the highest possible address? | |
1356 | */ | |
1363c3cd WW |
1357 | if (addr > mm->free_area_cache) |
1358 | mm->free_area_cache = addr; | |
1da177e4 LT |
1359 | |
1360 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1361 | if (mm->free_area_cache > mm->mmap_base) |
1362 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1363 | } |
1364 | ||
1365 | unsigned long | |
1366 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1367 | unsigned long pgoff, unsigned long flags) | |
1368 | { | |
06abdfb4 BH |
1369 | unsigned long (*get_area)(struct file *, unsigned long, |
1370 | unsigned long, unsigned long, unsigned long); | |
1371 | ||
1372 | get_area = current->mm->get_unmapped_area; | |
1373 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1374 | get_area = file->f_op->get_unmapped_area; | |
1375 | addr = get_area(file, addr, len, pgoff, flags); | |
1376 | if (IS_ERR_VALUE(addr)) | |
1377 | return addr; | |
1da177e4 | 1378 | |
07ab67c8 LT |
1379 | if (addr > TASK_SIZE - len) |
1380 | return -ENOMEM; | |
1381 | if (addr & ~PAGE_MASK) | |
1382 | return -EINVAL; | |
06abdfb4 | 1383 | |
07ab67c8 | 1384 | return addr; |
1da177e4 LT |
1385 | } |
1386 | ||
1387 | EXPORT_SYMBOL(get_unmapped_area); | |
1388 | ||
1389 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
1390 | struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) | |
1391 | { | |
1392 | struct vm_area_struct *vma = NULL; | |
1393 | ||
1394 | if (mm) { | |
1395 | /* Check the cache first. */ | |
1396 | /* (Cache hit rate is typically around 35%.) */ | |
1397 | vma = mm->mmap_cache; | |
1398 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1399 | struct rb_node * rb_node; | |
1400 | ||
1401 | rb_node = mm->mm_rb.rb_node; | |
1402 | vma = NULL; | |
1403 | ||
1404 | while (rb_node) { | |
1405 | struct vm_area_struct * vma_tmp; | |
1406 | ||
1407 | vma_tmp = rb_entry(rb_node, | |
1408 | struct vm_area_struct, vm_rb); | |
1409 | ||
1410 | if (vma_tmp->vm_end > addr) { | |
1411 | vma = vma_tmp; | |
1412 | if (vma_tmp->vm_start <= addr) | |
1413 | break; | |
1414 | rb_node = rb_node->rb_left; | |
1415 | } else | |
1416 | rb_node = rb_node->rb_right; | |
1417 | } | |
1418 | if (vma) | |
1419 | mm->mmap_cache = vma; | |
1420 | } | |
1421 | } | |
1422 | return vma; | |
1423 | } | |
1424 | ||
1425 | EXPORT_SYMBOL(find_vma); | |
1426 | ||
1427 | /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ | |
1428 | struct vm_area_struct * | |
1429 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1430 | struct vm_area_struct **pprev) | |
1431 | { | |
1432 | struct vm_area_struct *vma = NULL, *prev = NULL; | |
1433 | struct rb_node * rb_node; | |
1434 | if (!mm) | |
1435 | goto out; | |
1436 | ||
1437 | /* Guard against addr being lower than the first VMA */ | |
1438 | vma = mm->mmap; | |
1439 | ||
1440 | /* Go through the RB tree quickly. */ | |
1441 | rb_node = mm->mm_rb.rb_node; | |
1442 | ||
1443 | while (rb_node) { | |
1444 | struct vm_area_struct *vma_tmp; | |
1445 | vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1446 | ||
1447 | if (addr < vma_tmp->vm_end) { | |
1448 | rb_node = rb_node->rb_left; | |
1449 | } else { | |
1450 | prev = vma_tmp; | |
1451 | if (!prev->vm_next || (addr < prev->vm_next->vm_end)) | |
1452 | break; | |
1453 | rb_node = rb_node->rb_right; | |
1454 | } | |
1455 | } | |
1456 | ||
1457 | out: | |
1458 | *pprev = prev; | |
1459 | return prev ? prev->vm_next : vma; | |
1460 | } | |
1461 | ||
1462 | /* | |
1463 | * Verify that the stack growth is acceptable and | |
1464 | * update accounting. This is shared with both the | |
1465 | * grow-up and grow-down cases. | |
1466 | */ | |
1467 | static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) | |
1468 | { | |
1469 | struct mm_struct *mm = vma->vm_mm; | |
1470 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1471 | unsigned long new_start; |
1da177e4 LT |
1472 | |
1473 | /* address space limit tests */ | |
119f657c | 1474 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1475 | return -ENOMEM; |
1476 | ||
1477 | /* Stack limit test */ | |
1478 | if (size > rlim[RLIMIT_STACK].rlim_cur) | |
1479 | return -ENOMEM; | |
1480 | ||
1481 | /* mlock limit tests */ | |
1482 | if (vma->vm_flags & VM_LOCKED) { | |
1483 | unsigned long locked; | |
1484 | unsigned long limit; | |
1485 | locked = mm->locked_vm + grow; | |
1486 | limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; | |
1487 | if (locked > limit && !capable(CAP_IPC_LOCK)) | |
1488 | return -ENOMEM; | |
1489 | } | |
1490 | ||
0d59a01b AL |
1491 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1492 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1493 | vma->vm_end - size; | |
1494 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1495 | return -EFAULT; | |
1496 | ||
1da177e4 LT |
1497 | /* |
1498 | * Overcommit.. This must be the final test, as it will | |
1499 | * update security statistics. | |
1500 | */ | |
1501 | if (security_vm_enough_memory(grow)) | |
1502 | return -ENOMEM; | |
1503 | ||
1504 | /* Ok, everything looks good - let it rip */ | |
1505 | mm->total_vm += grow; | |
1506 | if (vma->vm_flags & VM_LOCKED) | |
1507 | mm->locked_vm += grow; | |
ab50b8ed | 1508 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1509 | return 0; |
1510 | } | |
1511 | ||
46dea3d0 | 1512 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1513 | /* |
46dea3d0 HD |
1514 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1515 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1516 | */ |
9ab88515 | 1517 | #ifndef CONFIG_IA64 |
46dea3d0 HD |
1518 | static inline |
1519 | #endif | |
1520 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) | |
1da177e4 LT |
1521 | { |
1522 | int error; | |
1523 | ||
1524 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1525 | return -EFAULT; | |
1526 | ||
1527 | /* | |
1528 | * We must make sure the anon_vma is allocated | |
1529 | * so that the anon_vma locking is not a noop. | |
1530 | */ | |
1531 | if (unlikely(anon_vma_prepare(vma))) | |
1532 | return -ENOMEM; | |
1533 | anon_vma_lock(vma); | |
1534 | ||
1535 | /* | |
1536 | * vma->vm_start/vm_end cannot change under us because the caller | |
1537 | * is required to hold the mmap_sem in read mode. We need the | |
1538 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1539 | */ | |
1540 | address += 4 + PAGE_SIZE - 1; | |
1541 | address &= PAGE_MASK; | |
1542 | error = 0; | |
1543 | ||
1544 | /* Somebody else might have raced and expanded it already */ | |
1545 | if (address > vma->vm_end) { | |
1546 | unsigned long size, grow; | |
1547 | ||
1548 | size = address - vma->vm_start; | |
1549 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1550 | ||
1551 | error = acct_stack_growth(vma, size, grow); | |
1552 | if (!error) | |
1553 | vma->vm_end = address; | |
1554 | } | |
1555 | anon_vma_unlock(vma); | |
1556 | return error; | |
1557 | } | |
46dea3d0 HD |
1558 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1559 | ||
1560 | #ifdef CONFIG_STACK_GROWSUP | |
1561 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1562 | { | |
1563 | return expand_upwards(vma, address); | |
1564 | } | |
1da177e4 LT |
1565 | |
1566 | struct vm_area_struct * | |
1567 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1568 | { | |
1569 | struct vm_area_struct *vma, *prev; | |
1570 | ||
1571 | addr &= PAGE_MASK; | |
1572 | vma = find_vma_prev(mm, addr, &prev); | |
1573 | if (vma && (vma->vm_start <= addr)) | |
1574 | return vma; | |
1575 | if (!prev || expand_stack(prev, addr)) | |
1576 | return NULL; | |
1577 | if (prev->vm_flags & VM_LOCKED) { | |
1578 | make_pages_present(addr, prev->vm_end); | |
1579 | } | |
1580 | return prev; | |
1581 | } | |
1582 | #else | |
1583 | /* | |
1584 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1585 | */ | |
1586 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1587 | { | |
1588 | int error; | |
1589 | ||
1590 | /* | |
1591 | * We must make sure the anon_vma is allocated | |
1592 | * so that the anon_vma locking is not a noop. | |
1593 | */ | |
1594 | if (unlikely(anon_vma_prepare(vma))) | |
1595 | return -ENOMEM; | |
1596 | anon_vma_lock(vma); | |
1597 | ||
1598 | /* | |
1599 | * vma->vm_start/vm_end cannot change under us because the caller | |
1600 | * is required to hold the mmap_sem in read mode. We need the | |
1601 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1602 | */ | |
1603 | address &= PAGE_MASK; | |
1604 | error = 0; | |
1605 | ||
1606 | /* Somebody else might have raced and expanded it already */ | |
1607 | if (address < vma->vm_start) { | |
1608 | unsigned long size, grow; | |
1609 | ||
1610 | size = vma->vm_end - address; | |
1611 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1612 | ||
1613 | error = acct_stack_growth(vma, size, grow); | |
1614 | if (!error) { | |
1615 | vma->vm_start = address; | |
1616 | vma->vm_pgoff -= grow; | |
1617 | } | |
1618 | } | |
1619 | anon_vma_unlock(vma); | |
1620 | return error; | |
1621 | } | |
1622 | ||
1623 | struct vm_area_struct * | |
1624 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1625 | { | |
1626 | struct vm_area_struct * vma; | |
1627 | unsigned long start; | |
1628 | ||
1629 | addr &= PAGE_MASK; | |
1630 | vma = find_vma(mm,addr); | |
1631 | if (!vma) | |
1632 | return NULL; | |
1633 | if (vma->vm_start <= addr) | |
1634 | return vma; | |
1635 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1636 | return NULL; | |
1637 | start = vma->vm_start; | |
1638 | if (expand_stack(vma, addr)) | |
1639 | return NULL; | |
1640 | if (vma->vm_flags & VM_LOCKED) { | |
1641 | make_pages_present(addr, start); | |
1642 | } | |
1643 | return vma; | |
1644 | } | |
1645 | #endif | |
1646 | ||
1da177e4 | 1647 | /* |
2c0b3814 | 1648 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1649 | * so release them, and do the vma updates. |
2c0b3814 HD |
1650 | * |
1651 | * Called with the mm semaphore held. | |
1da177e4 | 1652 | */ |
2c0b3814 | 1653 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1654 | { |
365e9c87 HD |
1655 | /* Update high watermark before we lower total_vm */ |
1656 | update_hiwater_vm(mm); | |
1da177e4 | 1657 | do { |
2c0b3814 HD |
1658 | long nrpages = vma_pages(vma); |
1659 | ||
1660 | mm->total_vm -= nrpages; | |
1661 | if (vma->vm_flags & VM_LOCKED) | |
1662 | mm->locked_vm -= nrpages; | |
1663 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); | |
a8fb5618 | 1664 | vma = remove_vma(vma); |
146425a3 | 1665 | } while (vma); |
1da177e4 LT |
1666 | validate_mm(mm); |
1667 | } | |
1668 | ||
1669 | /* | |
1670 | * Get rid of page table information in the indicated region. | |
1671 | * | |
f10df686 | 1672 | * Called with the mm semaphore held. |
1da177e4 LT |
1673 | */ |
1674 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1675 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1676 | unsigned long start, unsigned long end) | |
1da177e4 | 1677 | { |
e0da382c | 1678 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
1da177e4 LT |
1679 | struct mmu_gather *tlb; |
1680 | unsigned long nr_accounted = 0; | |
1681 | ||
1682 | lru_add_drain(); | |
1683 | tlb = tlb_gather_mmu(mm, 0); | |
365e9c87 | 1684 | update_hiwater_rss(mm); |
508034a3 | 1685 | unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); |
1da177e4 | 1686 | vm_unacct_memory(nr_accounted); |
e2cdef8c | 1687 | free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, |
e0da382c | 1688 | next? next->vm_start: 0); |
1da177e4 LT |
1689 | tlb_finish_mmu(tlb, start, end); |
1690 | } | |
1691 | ||
1692 | /* | |
1693 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1694 | * vma list as we go.. | |
1695 | */ | |
1696 | static void | |
1697 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1698 | struct vm_area_struct *prev, unsigned long end) | |
1699 | { | |
1700 | struct vm_area_struct **insertion_point; | |
1701 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1702 | unsigned long addr; |
1da177e4 LT |
1703 | |
1704 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
1705 | do { | |
1706 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1707 | mm->map_count--; | |
1708 | tail_vma = vma; | |
1709 | vma = vma->vm_next; | |
1710 | } while (vma && vma->vm_start < end); | |
1711 | *insertion_point = vma; | |
1712 | tail_vma->vm_next = NULL; | |
1363c3cd WW |
1713 | if (mm->unmap_area == arch_unmap_area) |
1714 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1715 | else | |
1716 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1717 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1718 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1719 | } | |
1720 | ||
1721 | /* | |
1722 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
59c51591 | 1723 | * either for the first part or the tail. |
1da177e4 LT |
1724 | */ |
1725 | int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, | |
1726 | unsigned long addr, int new_below) | |
1727 | { | |
1728 | struct mempolicy *pol; | |
1729 | struct vm_area_struct *new; | |
1730 | ||
1731 | if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) | |
1732 | return -EINVAL; | |
1733 | ||
1734 | if (mm->map_count >= sysctl_max_map_count) | |
1735 | return -ENOMEM; | |
1736 | ||
e94b1766 | 1737 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1738 | if (!new) |
1739 | return -ENOMEM; | |
1740 | ||
1741 | /* most fields are the same, copy all, and then fixup */ | |
1742 | *new = *vma; | |
1743 | ||
1744 | if (new_below) | |
1745 | new->vm_end = addr; | |
1746 | else { | |
1747 | new->vm_start = addr; | |
1748 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
1749 | } | |
1750 | ||
1751 | pol = mpol_copy(vma_policy(vma)); | |
1752 | if (IS_ERR(pol)) { | |
1753 | kmem_cache_free(vm_area_cachep, new); | |
1754 | return PTR_ERR(pol); | |
1755 | } | |
1756 | vma_set_policy(new, pol); | |
1757 | ||
1758 | if (new->vm_file) | |
1759 | get_file(new->vm_file); | |
1760 | ||
1761 | if (new->vm_ops && new->vm_ops->open) | |
1762 | new->vm_ops->open(new); | |
1763 | ||
1764 | if (new_below) | |
1765 | vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + | |
1766 | ((addr - new->vm_start) >> PAGE_SHIFT), new); | |
1767 | else | |
1768 | vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); | |
1769 | ||
1770 | return 0; | |
1771 | } | |
1772 | ||
1773 | /* Munmap is split into 2 main parts -- this part which finds | |
1774 | * what needs doing, and the areas themselves, which do the | |
1775 | * work. This now handles partial unmappings. | |
1776 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
1777 | */ | |
1778 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
1779 | { | |
1780 | unsigned long end; | |
146425a3 | 1781 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
1782 | |
1783 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
1784 | return -EINVAL; | |
1785 | ||
1786 | if ((len = PAGE_ALIGN(len)) == 0) | |
1787 | return -EINVAL; | |
1788 | ||
1789 | /* Find the first overlapping VMA */ | |
146425a3 HD |
1790 | vma = find_vma_prev(mm, start, &prev); |
1791 | if (!vma) | |
1da177e4 | 1792 | return 0; |
146425a3 | 1793 | /* we have start < vma->vm_end */ |
1da177e4 LT |
1794 | |
1795 | /* if it doesn't overlap, we have nothing.. */ | |
1796 | end = start + len; | |
146425a3 | 1797 | if (vma->vm_start >= end) |
1da177e4 LT |
1798 | return 0; |
1799 | ||
1800 | /* | |
1801 | * If we need to split any vma, do it now to save pain later. | |
1802 | * | |
1803 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
1804 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
1805 | * places tmp vma above, and higher split_vma places tmp vma below. | |
1806 | */ | |
146425a3 HD |
1807 | if (start > vma->vm_start) { |
1808 | int error = split_vma(mm, vma, start, 0); | |
1da177e4 LT |
1809 | if (error) |
1810 | return error; | |
146425a3 | 1811 | prev = vma; |
1da177e4 LT |
1812 | } |
1813 | ||
1814 | /* Does it split the last one? */ | |
1815 | last = find_vma(mm, end); | |
1816 | if (last && end > last->vm_start) { | |
1817 | int error = split_vma(mm, last, end, 1); | |
1818 | if (error) | |
1819 | return error; | |
1820 | } | |
146425a3 | 1821 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 LT |
1822 | |
1823 | /* | |
1824 | * Remove the vma's, and unmap the actual pages | |
1825 | */ | |
146425a3 HD |
1826 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
1827 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
1828 | |
1829 | /* Fix up all other VM information */ | |
2c0b3814 | 1830 | remove_vma_list(mm, vma); |
1da177e4 LT |
1831 | |
1832 | return 0; | |
1833 | } | |
1834 | ||
1835 | EXPORT_SYMBOL(do_munmap); | |
1836 | ||
1837 | asmlinkage long sys_munmap(unsigned long addr, size_t len) | |
1838 | { | |
1839 | int ret; | |
1840 | struct mm_struct *mm = current->mm; | |
1841 | ||
1842 | profile_munmap(addr); | |
1843 | ||
1844 | down_write(&mm->mmap_sem); | |
1845 | ret = do_munmap(mm, addr, len); | |
1846 | up_write(&mm->mmap_sem); | |
1847 | return ret; | |
1848 | } | |
1849 | ||
1850 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
1851 | { | |
a241ec65 | 1852 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
1853 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
1854 | WARN_ON(1); | |
1855 | up_read(&mm->mmap_sem); | |
1856 | } | |
1857 | #endif | |
1858 | } | |
1859 | ||
1860 | /* | |
1861 | * this is really a simplified "do_mmap". it only handles | |
1862 | * anonymous maps. eventually we may be able to do some | |
1863 | * brk-specific accounting here. | |
1864 | */ | |
1865 | unsigned long do_brk(unsigned long addr, unsigned long len) | |
1866 | { | |
1867 | struct mm_struct * mm = current->mm; | |
1868 | struct vm_area_struct * vma, * prev; | |
1869 | unsigned long flags; | |
1870 | struct rb_node ** rb_link, * rb_parent; | |
1871 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 1872 | int error; |
1da177e4 LT |
1873 | |
1874 | len = PAGE_ALIGN(len); | |
1875 | if (!len) | |
1876 | return addr; | |
1877 | ||
1878 | if ((addr + len) > TASK_SIZE || (addr + len) < addr) | |
1879 | return -EINVAL; | |
1880 | ||
cd2579d7 HD |
1881 | if (is_hugepage_only_range(mm, addr, len)) |
1882 | return -EINVAL; | |
cb07c9a1 | 1883 | |
3a459756 KK |
1884 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
1885 | ||
1886 | error = arch_mmap_check(addr, len, flags); | |
1887 | if (error) | |
1888 | return error; | |
1889 | ||
1da177e4 LT |
1890 | /* |
1891 | * mlock MCL_FUTURE? | |
1892 | */ | |
1893 | if (mm->def_flags & VM_LOCKED) { | |
1894 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
1895 | locked = len >> PAGE_SHIFT; |
1896 | locked += mm->locked_vm; | |
1da177e4 | 1897 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 1898 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
1899 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1900 | return -EAGAIN; | |
1901 | } | |
1902 | ||
1903 | /* | |
1904 | * mm->mmap_sem is required to protect against another thread | |
1905 | * changing the mappings in case we sleep. | |
1906 | */ | |
1907 | verify_mm_writelocked(mm); | |
1908 | ||
1909 | /* | |
1910 | * Clear old maps. this also does some error checking for us | |
1911 | */ | |
1912 | munmap_back: | |
1913 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1914 | if (vma && vma->vm_start < addr + len) { | |
1915 | if (do_munmap(mm, addr, len)) | |
1916 | return -ENOMEM; | |
1917 | goto munmap_back; | |
1918 | } | |
1919 | ||
1920 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 1921 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1922 | return -ENOMEM; |
1923 | ||
1924 | if (mm->map_count > sysctl_max_map_count) | |
1925 | return -ENOMEM; | |
1926 | ||
1927 | if (security_vm_enough_memory(len >> PAGE_SHIFT)) | |
1928 | return -ENOMEM; | |
1929 | ||
1da177e4 LT |
1930 | /* Can we just expand an old private anonymous mapping? */ |
1931 | if (vma_merge(mm, prev, addr, addr + len, flags, | |
1932 | NULL, NULL, pgoff, NULL)) | |
1933 | goto out; | |
1934 | ||
1935 | /* | |
1936 | * create a vma struct for an anonymous mapping | |
1937 | */ | |
c5e3b83e | 1938 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1939 | if (!vma) { |
1940 | vm_unacct_memory(len >> PAGE_SHIFT); | |
1941 | return -ENOMEM; | |
1942 | } | |
1da177e4 LT |
1943 | |
1944 | vma->vm_mm = mm; | |
1945 | vma->vm_start = addr; | |
1946 | vma->vm_end = addr + len; | |
1947 | vma->vm_pgoff = pgoff; | |
1948 | vma->vm_flags = flags; | |
9637a5ef DH |
1949 | vma->vm_page_prot = protection_map[flags & |
1950 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; | |
1da177e4 LT |
1951 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1952 | out: | |
1953 | mm->total_vm += len >> PAGE_SHIFT; | |
1954 | if (flags & VM_LOCKED) { | |
1955 | mm->locked_vm += len >> PAGE_SHIFT; | |
1956 | make_pages_present(addr, addr + len); | |
1957 | } | |
1958 | return addr; | |
1959 | } | |
1960 | ||
1961 | EXPORT_SYMBOL(do_brk); | |
1962 | ||
1963 | /* Release all mmaps. */ | |
1964 | void exit_mmap(struct mm_struct *mm) | |
1965 | { | |
1966 | struct mmu_gather *tlb; | |
e0da382c | 1967 | struct vm_area_struct *vma = mm->mmap; |
1da177e4 | 1968 | unsigned long nr_accounted = 0; |
ee39b37b | 1969 | unsigned long end; |
1da177e4 | 1970 | |
d6dd61c8 JF |
1971 | /* mm's last user has gone, and its about to be pulled down */ |
1972 | arch_exit_mmap(mm); | |
1973 | ||
1da177e4 | 1974 | lru_add_drain(); |
1da177e4 | 1975 | flush_cache_mm(mm); |
e0da382c | 1976 | tlb = tlb_gather_mmu(mm, 1); |
365e9c87 | 1977 | /* Don't update_hiwater_rss(mm) here, do_exit already did */ |
e0da382c | 1978 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
508034a3 | 1979 | end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); |
1da177e4 | 1980 | vm_unacct_memory(nr_accounted); |
e2cdef8c | 1981 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
ee39b37b | 1982 | tlb_finish_mmu(tlb, 0, end); |
1da177e4 | 1983 | |
1da177e4 | 1984 | /* |
8f4f8c16 HD |
1985 | * Walk the list again, actually closing and freeing it, |
1986 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 1987 | */ |
a8fb5618 HD |
1988 | while (vma) |
1989 | vma = remove_vma(vma); | |
e0da382c | 1990 | |
e2cdef8c | 1991 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
1992 | } |
1993 | ||
1994 | /* Insert vm structure into process list sorted by address | |
1995 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
1996 | * then i_mmap_lock is taken here. | |
1997 | */ | |
1998 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
1999 | { | |
2000 | struct vm_area_struct * __vma, * prev; | |
2001 | struct rb_node ** rb_link, * rb_parent; | |
2002 | ||
2003 | /* | |
2004 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2005 | * until its first write fault, when page's anon_vma and index | |
2006 | * are set. But now set the vm_pgoff it will almost certainly | |
2007 | * end up with (unless mremap moves it elsewhere before that | |
2008 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2009 | * | |
2010 | * By setting it to reflect the virtual start address of the | |
2011 | * vma, merges and splits can happen in a seamless way, just | |
2012 | * using the existing file pgoff checks and manipulations. | |
2013 | * Similarly in do_mmap_pgoff and in do_brk. | |
2014 | */ | |
2015 | if (!vma->vm_file) { | |
2016 | BUG_ON(vma->anon_vma); | |
2017 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2018 | } | |
2019 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); | |
2020 | if (__vma && __vma->vm_start < vma->vm_end) | |
2021 | return -ENOMEM; | |
2fd4ef85 HD |
2022 | if ((vma->vm_flags & VM_ACCOUNT) && |
2023 | security_vm_enough_memory(vma_pages(vma))) | |
2024 | return -ENOMEM; | |
1da177e4 LT |
2025 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2026 | return 0; | |
2027 | } | |
2028 | ||
2029 | /* | |
2030 | * Copy the vma structure to a new location in the same mm, | |
2031 | * prior to moving page table entries, to effect an mremap move. | |
2032 | */ | |
2033 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
2034 | unsigned long addr, unsigned long len, pgoff_t pgoff) | |
2035 | { | |
2036 | struct vm_area_struct *vma = *vmap; | |
2037 | unsigned long vma_start = vma->vm_start; | |
2038 | struct mm_struct *mm = vma->vm_mm; | |
2039 | struct vm_area_struct *new_vma, *prev; | |
2040 | struct rb_node **rb_link, *rb_parent; | |
2041 | struct mempolicy *pol; | |
2042 | ||
2043 | /* | |
2044 | * If anonymous vma has not yet been faulted, update new pgoff | |
2045 | * to match new location, to increase its chance of merging. | |
2046 | */ | |
2047 | if (!vma->vm_file && !vma->anon_vma) | |
2048 | pgoff = addr >> PAGE_SHIFT; | |
2049 | ||
2050 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2051 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, | |
2052 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2053 | if (new_vma) { | |
2054 | /* | |
2055 | * Source vma may have been merged into new_vma | |
2056 | */ | |
2057 | if (vma_start >= new_vma->vm_start && | |
2058 | vma_start < new_vma->vm_end) | |
2059 | *vmap = new_vma; | |
2060 | } else { | |
e94b1766 | 2061 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2062 | if (new_vma) { |
2063 | *new_vma = *vma; | |
2064 | pol = mpol_copy(vma_policy(vma)); | |
2065 | if (IS_ERR(pol)) { | |
2066 | kmem_cache_free(vm_area_cachep, new_vma); | |
2067 | return NULL; | |
2068 | } | |
2069 | vma_set_policy(new_vma, pol); | |
2070 | new_vma->vm_start = addr; | |
2071 | new_vma->vm_end = addr + len; | |
2072 | new_vma->vm_pgoff = pgoff; | |
2073 | if (new_vma->vm_file) | |
2074 | get_file(new_vma->vm_file); | |
2075 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
2076 | new_vma->vm_ops->open(new_vma); | |
2077 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
2078 | } | |
2079 | } | |
2080 | return new_vma; | |
2081 | } | |
119f657c | 2082 | |
2083 | /* | |
2084 | * Return true if the calling process may expand its vm space by the passed | |
2085 | * number of pages | |
2086 | */ | |
2087 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2088 | { | |
2089 | unsigned long cur = mm->total_vm; /* pages */ | |
2090 | unsigned long lim; | |
2091 | ||
2092 | lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; | |
2093 | ||
2094 | if (cur + npages > lim) | |
2095 | return 0; | |
2096 | return 1; | |
2097 | } | |
fa5dc22f RM |
2098 | |
2099 | ||
2100 | static struct page *special_mapping_nopage(struct vm_area_struct *vma, | |
2101 | unsigned long address, int *type) | |
2102 | { | |
2103 | struct page **pages; | |
2104 | ||
2105 | BUG_ON(address < vma->vm_start || address >= vma->vm_end); | |
2106 | ||
2107 | address -= vma->vm_start; | |
2108 | for (pages = vma->vm_private_data; address > 0 && *pages; ++pages) | |
2109 | address -= PAGE_SIZE; | |
2110 | ||
2111 | if (*pages) { | |
2112 | struct page *page = *pages; | |
2113 | get_page(page); | |
2114 | return page; | |
2115 | } | |
2116 | ||
2117 | return NOPAGE_SIGBUS; | |
2118 | } | |
2119 | ||
2120 | /* | |
2121 | * Having a close hook prevents vma merging regardless of flags. | |
2122 | */ | |
2123 | static void special_mapping_close(struct vm_area_struct *vma) | |
2124 | { | |
2125 | } | |
2126 | ||
2127 | static struct vm_operations_struct special_mapping_vmops = { | |
2128 | .close = special_mapping_close, | |
2129 | .nopage = special_mapping_nopage, | |
2130 | }; | |
2131 | ||
2132 | /* | |
2133 | * Called with mm->mmap_sem held for writing. | |
2134 | * Insert a new vma covering the given region, with the given flags. | |
2135 | * Its pages are supplied by the given array of struct page *. | |
2136 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2137 | * The region past the last page supplied will always produce SIGBUS. | |
2138 | * The array pointer and the pages it points to are assumed to stay alive | |
2139 | * for as long as this mapping might exist. | |
2140 | */ | |
2141 | int install_special_mapping(struct mm_struct *mm, | |
2142 | unsigned long addr, unsigned long len, | |
2143 | unsigned long vm_flags, struct page **pages) | |
2144 | { | |
2145 | struct vm_area_struct *vma; | |
2146 | ||
2147 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2148 | if (unlikely(vma == NULL)) | |
2149 | return -ENOMEM; | |
2150 | ||
2151 | vma->vm_mm = mm; | |
2152 | vma->vm_start = addr; | |
2153 | vma->vm_end = addr + len; | |
2154 | ||
2155 | vma->vm_flags = vm_flags | mm->def_flags; | |
2156 | vma->vm_page_prot = protection_map[vma->vm_flags & 7]; | |
2157 | ||
2158 | vma->vm_ops = &special_mapping_vmops; | |
2159 | vma->vm_private_data = pages; | |
2160 | ||
2161 | if (unlikely(insert_vm_struct(mm, vma))) { | |
2162 | kmem_cache_free(vm_area_cachep, vma); | |
2163 | return -ENOMEM; | |
2164 | } | |
2165 | ||
2166 | mm->total_vm += len >> PAGE_SHIFT; | |
2167 | ||
2168 | return 0; | |
2169 | } |