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> | |
4af3c9cc | 10 | #include <linux/backing-dev.h> |
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/shm.h> | |
13 | #include <linux/mman.h> | |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/swap.h> | |
16 | #include <linux/syscalls.h> | |
c59ede7b | 17 | #include <linux/capability.h> |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/file.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/security.h> | |
23 | #include <linux/hugetlb.h> | |
24 | #include <linux/profile.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/mount.h> | |
27 | #include <linux/mempolicy.h> | |
28 | #include <linux/rmap.h> | |
29 | ||
30 | #include <asm/uaccess.h> | |
31 | #include <asm/cacheflush.h> | |
32 | #include <asm/tlb.h> | |
d6dd61c8 | 33 | #include <asm/mmu_context.h> |
1da177e4 | 34 | |
3a459756 KK |
35 | #ifndef arch_mmap_check |
36 | #define arch_mmap_check(addr, len, flags) (0) | |
37 | #endif | |
38 | ||
08e7d9b5 MS |
39 | #ifndef arch_rebalance_pgtables |
40 | #define arch_rebalance_pgtables(addr, len) (addr) | |
41 | #endif | |
42 | ||
e0da382c HD |
43 | static void unmap_region(struct mm_struct *mm, |
44 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
45 | unsigned long start, unsigned long end); | |
46 | ||
1da177e4 LT |
47 | /* |
48 | * WARNING: the debugging will use recursive algorithms so never enable this | |
49 | * unless you know what you are doing. | |
50 | */ | |
51 | #undef DEBUG_MM_RB | |
52 | ||
53 | /* description of effects of mapping type and prot in current implementation. | |
54 | * this is due to the limited x86 page protection hardware. The expected | |
55 | * behavior is in parens: | |
56 | * | |
57 | * map_type prot | |
58 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
59 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
60 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
61 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
62 | * | |
63 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
64 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
65 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
66 | * | |
67 | */ | |
68 | pgprot_t protection_map[16] = { | |
69 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
70 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
71 | }; | |
72 | ||
804af2cf HD |
73 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
74 | { | |
75 | return protection_map[vm_flags & | |
76 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; | |
77 | } | |
78 | EXPORT_SYMBOL(vm_get_page_prot); | |
79 | ||
1da177e4 LT |
80 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
81 | int sysctl_overcommit_ratio = 50; /* default is 50% */ | |
c3d8c141 | 82 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
1da177e4 LT |
83 | atomic_t vm_committed_space = ATOMIC_INIT(0); |
84 | ||
85 | /* | |
86 | * Check that a process has enough memory to allocate a new virtual | |
87 | * mapping. 0 means there is enough memory for the allocation to | |
88 | * succeed and -ENOMEM implies there is not. | |
89 | * | |
90 | * We currently support three overcommit policies, which are set via the | |
91 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
92 | * | |
93 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
94 | * Additional code 2002 Jul 20 by Robert Love. | |
95 | * | |
96 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
97 | * | |
98 | * Note this is a helper function intended to be used by LSMs which | |
99 | * wish to use this logic. | |
100 | */ | |
34b4e4aa | 101 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
102 | { |
103 | unsigned long free, allowed; | |
104 | ||
105 | vm_acct_memory(pages); | |
106 | ||
107 | /* | |
108 | * Sometimes we want to use more memory than we have | |
109 | */ | |
110 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
111 | return 0; | |
112 | ||
113 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
114 | unsigned long n; | |
115 | ||
347ce434 | 116 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
117 | free += nr_swap_pages; |
118 | ||
119 | /* | |
120 | * Any slabs which are created with the | |
121 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
122 | * which are reclaimable, under pressure. The dentry | |
123 | * cache and most inode caches should fall into this | |
124 | */ | |
972d1a7b | 125 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
126 | |
127 | /* | |
128 | * Leave the last 3% for root | |
129 | */ | |
130 | if (!cap_sys_admin) | |
131 | free -= free / 32; | |
132 | ||
133 | if (free > pages) | |
134 | return 0; | |
135 | ||
136 | /* | |
137 | * nr_free_pages() is very expensive on large systems, | |
138 | * only call if we're about to fail. | |
139 | */ | |
140 | n = nr_free_pages(); | |
6d9f7839 HA |
141 | |
142 | /* | |
143 | * Leave reserved pages. The pages are not for anonymous pages. | |
144 | */ | |
145 | if (n <= totalreserve_pages) | |
146 | goto error; | |
147 | else | |
148 | n -= totalreserve_pages; | |
149 | ||
150 | /* | |
151 | * Leave the last 3% for root | |
152 | */ | |
1da177e4 LT |
153 | if (!cap_sys_admin) |
154 | n -= n / 32; | |
155 | free += n; | |
156 | ||
157 | if (free > pages) | |
158 | return 0; | |
6d9f7839 HA |
159 | |
160 | goto error; | |
1da177e4 LT |
161 | } |
162 | ||
163 | allowed = (totalram_pages - hugetlb_total_pages()) | |
164 | * sysctl_overcommit_ratio / 100; | |
165 | /* | |
166 | * Leave the last 3% for root | |
167 | */ | |
168 | if (!cap_sys_admin) | |
169 | allowed -= allowed / 32; | |
170 | allowed += total_swap_pages; | |
171 | ||
172 | /* Don't let a single process grow too big: | |
173 | leave 3% of the size of this process for other processes */ | |
34b4e4aa | 174 | allowed -= mm->total_vm / 32; |
1da177e4 | 175 | |
2f60f8d3 SD |
176 | /* |
177 | * cast `allowed' as a signed long because vm_committed_space | |
178 | * sometimes has a negative value | |
179 | */ | |
180 | if (atomic_read(&vm_committed_space) < (long)allowed) | |
1da177e4 | 181 | return 0; |
6d9f7839 | 182 | error: |
1da177e4 LT |
183 | vm_unacct_memory(pages); |
184 | ||
185 | return -ENOMEM; | |
186 | } | |
187 | ||
1da177e4 LT |
188 | /* |
189 | * Requires inode->i_mapping->i_mmap_lock | |
190 | */ | |
191 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
192 | struct file *file, struct address_space *mapping) | |
193 | { | |
194 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 195 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
196 | if (vma->vm_flags & VM_SHARED) |
197 | mapping->i_mmap_writable--; | |
198 | ||
199 | flush_dcache_mmap_lock(mapping); | |
200 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
201 | list_del_init(&vma->shared.vm_set.list); | |
202 | else | |
203 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
204 | flush_dcache_mmap_unlock(mapping); | |
205 | } | |
206 | ||
207 | /* | |
a8fb5618 HD |
208 | * Unlink a file-based vm structure from its prio_tree, to hide |
209 | * vma from rmap and vmtruncate before freeing its page tables. | |
1da177e4 | 210 | */ |
a8fb5618 | 211 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
212 | { |
213 | struct file *file = vma->vm_file; | |
214 | ||
1da177e4 LT |
215 | if (file) { |
216 | struct address_space *mapping = file->f_mapping; | |
217 | spin_lock(&mapping->i_mmap_lock); | |
218 | __remove_shared_vm_struct(vma, file, mapping); | |
219 | spin_unlock(&mapping->i_mmap_lock); | |
220 | } | |
a8fb5618 HD |
221 | } |
222 | ||
223 | /* | |
224 | * Close a vm structure and free it, returning the next. | |
225 | */ | |
226 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
227 | { | |
228 | struct vm_area_struct *next = vma->vm_next; | |
229 | ||
a8fb5618 | 230 | might_sleep(); |
1da177e4 LT |
231 | if (vma->vm_ops && vma->vm_ops->close) |
232 | vma->vm_ops->close(vma); | |
925d1c40 | 233 | if (vma->vm_file) { |
a8fb5618 | 234 | fput(vma->vm_file); |
925d1c40 MH |
235 | if (vma->vm_flags & VM_EXECUTABLE) |
236 | removed_exe_file_vma(vma->vm_mm); | |
237 | } | |
f0be3d32 | 238 | mpol_put(vma_policy(vma)); |
1da177e4 | 239 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 240 | return next; |
1da177e4 LT |
241 | } |
242 | ||
1da177e4 LT |
243 | asmlinkage unsigned long sys_brk(unsigned long brk) |
244 | { | |
245 | unsigned long rlim, retval; | |
246 | unsigned long newbrk, oldbrk; | |
247 | struct mm_struct *mm = current->mm; | |
248 | ||
249 | down_write(&mm->mmap_sem); | |
250 | ||
4cc6028d | 251 | if (brk < mm->start_brk) |
1da177e4 | 252 | goto out; |
1e624196 RG |
253 | |
254 | /* | |
255 | * Check against rlimit here. If this check is done later after the test | |
256 | * of oldbrk with newbrk then it can escape the test and let the data | |
257 | * segment grow beyond its set limit the in case where the limit is | |
258 | * not page aligned -Ram Gupta | |
259 | */ | |
260 | rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; | |
c1d171a0 JK |
261 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
262 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
263 | goto out; |
264 | ||
1da177e4 LT |
265 | newbrk = PAGE_ALIGN(brk); |
266 | oldbrk = PAGE_ALIGN(mm->brk); | |
267 | if (oldbrk == newbrk) | |
268 | goto set_brk; | |
269 | ||
270 | /* Always allow shrinking brk. */ | |
271 | if (brk <= mm->brk) { | |
272 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
273 | goto set_brk; | |
274 | goto out; | |
275 | } | |
276 | ||
1da177e4 LT |
277 | /* Check against existing mmap mappings. */ |
278 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
279 | goto out; | |
280 | ||
281 | /* Ok, looks good - let it rip. */ | |
282 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
283 | goto out; | |
284 | set_brk: | |
285 | mm->brk = brk; | |
286 | out: | |
287 | retval = mm->brk; | |
288 | up_write(&mm->mmap_sem); | |
289 | return retval; | |
290 | } | |
291 | ||
292 | #ifdef DEBUG_MM_RB | |
293 | static int browse_rb(struct rb_root *root) | |
294 | { | |
295 | int i = 0, j; | |
296 | struct rb_node *nd, *pn = NULL; | |
297 | unsigned long prev = 0, pend = 0; | |
298 | ||
299 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
300 | struct vm_area_struct *vma; | |
301 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
302 | if (vma->vm_start < prev) | |
303 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
304 | if (vma->vm_start < pend) | |
305 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
306 | if (vma->vm_start > vma->vm_end) | |
307 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
308 | i++; | |
309 | pn = nd; | |
d1af65d1 DM |
310 | prev = vma->vm_start; |
311 | pend = vma->vm_end; | |
1da177e4 LT |
312 | } |
313 | j = 0; | |
314 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
315 | j++; | |
316 | } | |
317 | if (i != j) | |
318 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
319 | return i; | |
320 | } | |
321 | ||
322 | void validate_mm(struct mm_struct *mm) | |
323 | { | |
324 | int bug = 0; | |
325 | int i = 0; | |
326 | struct vm_area_struct *tmp = mm->mmap; | |
327 | while (tmp) { | |
328 | tmp = tmp->vm_next; | |
329 | i++; | |
330 | } | |
331 | if (i != mm->map_count) | |
332 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
333 | i = browse_rb(&mm->mm_rb); | |
334 | if (i != mm->map_count) | |
335 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 336 | BUG_ON(bug); |
1da177e4 LT |
337 | } |
338 | #else | |
339 | #define validate_mm(mm) do { } while (0) | |
340 | #endif | |
341 | ||
342 | static struct vm_area_struct * | |
343 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, | |
344 | struct vm_area_struct **pprev, struct rb_node ***rb_link, | |
345 | struct rb_node ** rb_parent) | |
346 | { | |
347 | struct vm_area_struct * vma; | |
348 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; | |
349 | ||
350 | __rb_link = &mm->mm_rb.rb_node; | |
351 | rb_prev = __rb_parent = NULL; | |
352 | vma = NULL; | |
353 | ||
354 | while (*__rb_link) { | |
355 | struct vm_area_struct *vma_tmp; | |
356 | ||
357 | __rb_parent = *__rb_link; | |
358 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
359 | ||
360 | if (vma_tmp->vm_end > addr) { | |
361 | vma = vma_tmp; | |
362 | if (vma_tmp->vm_start <= addr) | |
363 | return vma; | |
364 | __rb_link = &__rb_parent->rb_left; | |
365 | } else { | |
366 | rb_prev = __rb_parent; | |
367 | __rb_link = &__rb_parent->rb_right; | |
368 | } | |
369 | } | |
370 | ||
371 | *pprev = NULL; | |
372 | if (rb_prev) | |
373 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
374 | *rb_link = __rb_link; | |
375 | *rb_parent = __rb_parent; | |
376 | return vma; | |
377 | } | |
378 | ||
379 | static inline void | |
380 | __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, | |
381 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
382 | { | |
383 | if (prev) { | |
384 | vma->vm_next = prev->vm_next; | |
385 | prev->vm_next = vma; | |
386 | } else { | |
387 | mm->mmap = vma; | |
388 | if (rb_parent) | |
389 | vma->vm_next = rb_entry(rb_parent, | |
390 | struct vm_area_struct, vm_rb); | |
391 | else | |
392 | vma->vm_next = NULL; | |
393 | } | |
394 | } | |
395 | ||
396 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, | |
397 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
398 | { | |
399 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
400 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
401 | } | |
402 | ||
403 | static inline void __vma_link_file(struct vm_area_struct *vma) | |
404 | { | |
405 | struct file * file; | |
406 | ||
407 | file = vma->vm_file; | |
408 | if (file) { | |
409 | struct address_space *mapping = file->f_mapping; | |
410 | ||
411 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 412 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
413 | if (vma->vm_flags & VM_SHARED) |
414 | mapping->i_mmap_writable++; | |
415 | ||
416 | flush_dcache_mmap_lock(mapping); | |
417 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
418 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
419 | else | |
420 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
421 | flush_dcache_mmap_unlock(mapping); | |
422 | } | |
423 | } | |
424 | ||
425 | static void | |
426 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
427 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
428 | struct rb_node *rb_parent) | |
429 | { | |
430 | __vma_link_list(mm, vma, prev, rb_parent); | |
431 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
432 | __anon_vma_link(vma); | |
433 | } | |
434 | ||
435 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
436 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
437 | struct rb_node *rb_parent) | |
438 | { | |
439 | struct address_space *mapping = NULL; | |
440 | ||
441 | if (vma->vm_file) | |
442 | mapping = vma->vm_file->f_mapping; | |
443 | ||
444 | if (mapping) { | |
445 | spin_lock(&mapping->i_mmap_lock); | |
446 | vma->vm_truncate_count = mapping->truncate_count; | |
447 | } | |
448 | anon_vma_lock(vma); | |
449 | ||
450 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
451 | __vma_link_file(vma); | |
452 | ||
453 | anon_vma_unlock(vma); | |
454 | if (mapping) | |
455 | spin_unlock(&mapping->i_mmap_lock); | |
456 | ||
457 | mm->map_count++; | |
458 | validate_mm(mm); | |
459 | } | |
460 | ||
461 | /* | |
462 | * Helper for vma_adjust in the split_vma insert case: | |
463 | * insert vm structure into list and rbtree and anon_vma, | |
464 | * but it has already been inserted into prio_tree earlier. | |
465 | */ | |
466 | static void | |
467 | __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
468 | { | |
469 | struct vm_area_struct * __vma, * prev; | |
470 | struct rb_node ** rb_link, * rb_parent; | |
471 | ||
472 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); | |
46a350ef | 473 | BUG_ON(__vma && __vma->vm_start < vma->vm_end); |
1da177e4 LT |
474 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
475 | mm->map_count++; | |
476 | } | |
477 | ||
478 | static inline void | |
479 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
480 | struct vm_area_struct *prev) | |
481 | { | |
482 | prev->vm_next = vma->vm_next; | |
483 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
484 | if (mm->mmap_cache == vma) | |
485 | mm->mmap_cache = prev; | |
486 | } | |
487 | ||
488 | /* | |
489 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
490 | * is already present in an i_mmap tree without adjusting the tree. | |
491 | * The following helper function should be used when such adjustments | |
492 | * are necessary. The "insert" vma (if any) is to be inserted | |
493 | * before we drop the necessary locks. | |
494 | */ | |
495 | void vma_adjust(struct vm_area_struct *vma, unsigned long start, | |
496 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) | |
497 | { | |
498 | struct mm_struct *mm = vma->vm_mm; | |
499 | struct vm_area_struct *next = vma->vm_next; | |
500 | struct vm_area_struct *importer = NULL; | |
501 | struct address_space *mapping = NULL; | |
502 | struct prio_tree_root *root = NULL; | |
503 | struct file *file = vma->vm_file; | |
504 | struct anon_vma *anon_vma = NULL; | |
505 | long adjust_next = 0; | |
506 | int remove_next = 0; | |
507 | ||
508 | if (next && !insert) { | |
509 | if (end >= next->vm_end) { | |
510 | /* | |
511 | * vma expands, overlapping all the next, and | |
512 | * perhaps the one after too (mprotect case 6). | |
513 | */ | |
514 | again: remove_next = 1 + (end > next->vm_end); | |
515 | end = next->vm_end; | |
516 | anon_vma = next->anon_vma; | |
517 | importer = vma; | |
518 | } else if (end > next->vm_start) { | |
519 | /* | |
520 | * vma expands, overlapping part of the next: | |
521 | * mprotect case 5 shifting the boundary up. | |
522 | */ | |
523 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
524 | anon_vma = next->anon_vma; | |
525 | importer = vma; | |
526 | } else if (end < vma->vm_end) { | |
527 | /* | |
528 | * vma shrinks, and !insert tells it's not | |
529 | * split_vma inserting another: so it must be | |
530 | * mprotect case 4 shifting the boundary down. | |
531 | */ | |
532 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
533 | anon_vma = next->anon_vma; | |
534 | importer = next; | |
535 | } | |
536 | } | |
537 | ||
538 | if (file) { | |
539 | mapping = file->f_mapping; | |
540 | if (!(vma->vm_flags & VM_NONLINEAR)) | |
541 | root = &mapping->i_mmap; | |
542 | spin_lock(&mapping->i_mmap_lock); | |
543 | if (importer && | |
544 | vma->vm_truncate_count != next->vm_truncate_count) { | |
545 | /* | |
546 | * unmap_mapping_range might be in progress: | |
547 | * ensure that the expanding vma is rescanned. | |
548 | */ | |
549 | importer->vm_truncate_count = 0; | |
550 | } | |
551 | if (insert) { | |
552 | insert->vm_truncate_count = vma->vm_truncate_count; | |
553 | /* | |
554 | * Put into prio_tree now, so instantiated pages | |
555 | * are visible to arm/parisc __flush_dcache_page | |
556 | * throughout; but we cannot insert into address | |
557 | * space until vma start or end is updated. | |
558 | */ | |
559 | __vma_link_file(insert); | |
560 | } | |
561 | } | |
562 | ||
563 | /* | |
564 | * When changing only vma->vm_end, we don't really need | |
565 | * anon_vma lock: but is that case worth optimizing out? | |
566 | */ | |
567 | if (vma->anon_vma) | |
568 | anon_vma = vma->anon_vma; | |
569 | if (anon_vma) { | |
570 | spin_lock(&anon_vma->lock); | |
571 | /* | |
572 | * Easily overlooked: when mprotect shifts the boundary, | |
573 | * make sure the expanding vma has anon_vma set if the | |
574 | * shrinking vma had, to cover any anon pages imported. | |
575 | */ | |
576 | if (importer && !importer->anon_vma) { | |
577 | importer->anon_vma = anon_vma; | |
578 | __anon_vma_link(importer); | |
579 | } | |
580 | } | |
581 | ||
582 | if (root) { | |
583 | flush_dcache_mmap_lock(mapping); | |
584 | vma_prio_tree_remove(vma, root); | |
585 | if (adjust_next) | |
586 | vma_prio_tree_remove(next, root); | |
587 | } | |
588 | ||
589 | vma->vm_start = start; | |
590 | vma->vm_end = end; | |
591 | vma->vm_pgoff = pgoff; | |
592 | if (adjust_next) { | |
593 | next->vm_start += adjust_next << PAGE_SHIFT; | |
594 | next->vm_pgoff += adjust_next; | |
595 | } | |
596 | ||
597 | if (root) { | |
598 | if (adjust_next) | |
599 | vma_prio_tree_insert(next, root); | |
600 | vma_prio_tree_insert(vma, root); | |
601 | flush_dcache_mmap_unlock(mapping); | |
602 | } | |
603 | ||
604 | if (remove_next) { | |
605 | /* | |
606 | * vma_merge has merged next into vma, and needs | |
607 | * us to remove next before dropping the locks. | |
608 | */ | |
609 | __vma_unlink(mm, next, vma); | |
610 | if (file) | |
611 | __remove_shared_vm_struct(next, file, mapping); | |
612 | if (next->anon_vma) | |
613 | __anon_vma_merge(vma, next); | |
614 | } else if (insert) { | |
615 | /* | |
616 | * split_vma has split insert from vma, and needs | |
617 | * us to insert it before dropping the locks | |
618 | * (it may either follow vma or precede it). | |
619 | */ | |
620 | __insert_vm_struct(mm, insert); | |
621 | } | |
622 | ||
623 | if (anon_vma) | |
624 | spin_unlock(&anon_vma->lock); | |
625 | if (mapping) | |
626 | spin_unlock(&mapping->i_mmap_lock); | |
627 | ||
628 | if (remove_next) { | |
925d1c40 | 629 | if (file) { |
1da177e4 | 630 | fput(file); |
925d1c40 MH |
631 | if (next->vm_flags & VM_EXECUTABLE) |
632 | removed_exe_file_vma(mm); | |
633 | } | |
1da177e4 | 634 | mm->map_count--; |
f0be3d32 | 635 | mpol_put(vma_policy(next)); |
1da177e4 LT |
636 | kmem_cache_free(vm_area_cachep, next); |
637 | /* | |
638 | * In mprotect's case 6 (see comments on vma_merge), | |
639 | * we must remove another next too. It would clutter | |
640 | * up the code too much to do both in one go. | |
641 | */ | |
642 | if (remove_next == 2) { | |
643 | next = vma->vm_next; | |
644 | goto again; | |
645 | } | |
646 | } | |
647 | ||
648 | validate_mm(mm); | |
649 | } | |
650 | ||
651 | /* | |
652 | * If the vma has a ->close operation then the driver probably needs to release | |
653 | * per-vma resources, so we don't attempt to merge those. | |
654 | */ | |
a6f563db | 655 | #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) |
1da177e4 LT |
656 | |
657 | static inline int is_mergeable_vma(struct vm_area_struct *vma, | |
658 | struct file *file, unsigned long vm_flags) | |
659 | { | |
660 | if (vma->vm_flags != vm_flags) | |
661 | return 0; | |
662 | if (vma->vm_file != file) | |
663 | return 0; | |
664 | if (vma->vm_ops && vma->vm_ops->close) | |
665 | return 0; | |
666 | return 1; | |
667 | } | |
668 | ||
669 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
670 | struct anon_vma *anon_vma2) | |
671 | { | |
672 | return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); | |
673 | } | |
674 | ||
675 | /* | |
676 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
677 | * in front of (at a lower virtual address and file offset than) the vma. | |
678 | * | |
679 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
680 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
681 | * | |
682 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
683 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
684 | * wrap, nor mmaps which cover the final page at index -1UL. | |
685 | */ | |
686 | static int | |
687 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
688 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
689 | { | |
690 | if (is_mergeable_vma(vma, file, vm_flags) && | |
691 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
692 | if (vma->vm_pgoff == vm_pgoff) | |
693 | return 1; | |
694 | } | |
695 | return 0; | |
696 | } | |
697 | ||
698 | /* | |
699 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
700 | * beyond (at a higher virtual address and file offset than) the vma. | |
701 | * | |
702 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
703 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
704 | */ | |
705 | static int | |
706 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
707 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
708 | { | |
709 | if (is_mergeable_vma(vma, file, vm_flags) && | |
710 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { | |
711 | pgoff_t vm_pglen; | |
712 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
713 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
714 | return 1; | |
715 | } | |
716 | return 0; | |
717 | } | |
718 | ||
719 | /* | |
720 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
721 | * whether that can be merged with its predecessor or its successor. | |
722 | * Or both (it neatly fills a hole). | |
723 | * | |
724 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
725 | * certain not to be mapped by the time vma_merge is called; but when | |
726 | * called for mprotect, it is certain to be already mapped (either at | |
727 | * an offset within prev, or at the start of next), and the flags of | |
728 | * this area are about to be changed to vm_flags - and the no-change | |
729 | * case has already been eliminated. | |
730 | * | |
731 | * The following mprotect cases have to be considered, where AAAA is | |
732 | * the area passed down from mprotect_fixup, never extending beyond one | |
733 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
734 | * | |
735 | * AAAA AAAA AAAA AAAA | |
736 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
737 | * cannot merge might become might become might become | |
738 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
739 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
740 | * mremap move: PPPPNNNNNNNN 8 | |
741 | * AAAA | |
742 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
743 | * might become case 1 below case 2 below case 3 below | |
744 | * | |
745 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
746 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
747 | */ | |
748 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
749 | struct vm_area_struct *prev, unsigned long addr, | |
750 | unsigned long end, unsigned long vm_flags, | |
751 | struct anon_vma *anon_vma, struct file *file, | |
752 | pgoff_t pgoff, struct mempolicy *policy) | |
753 | { | |
754 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
755 | struct vm_area_struct *area, *next; | |
756 | ||
757 | /* | |
758 | * We later require that vma->vm_flags == vm_flags, | |
759 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
760 | */ | |
761 | if (vm_flags & VM_SPECIAL) | |
762 | return NULL; | |
763 | ||
764 | if (prev) | |
765 | next = prev->vm_next; | |
766 | else | |
767 | next = mm->mmap; | |
768 | area = next; | |
769 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
770 | next = next->vm_next; | |
771 | ||
772 | /* | |
773 | * Can it merge with the predecessor? | |
774 | */ | |
775 | if (prev && prev->vm_end == addr && | |
776 | mpol_equal(vma_policy(prev), policy) && | |
777 | can_vma_merge_after(prev, vm_flags, | |
778 | anon_vma, file, pgoff)) { | |
779 | /* | |
780 | * OK, it can. Can we now merge in the successor as well? | |
781 | */ | |
782 | if (next && end == next->vm_start && | |
783 | mpol_equal(policy, vma_policy(next)) && | |
784 | can_vma_merge_before(next, vm_flags, | |
785 | anon_vma, file, pgoff+pglen) && | |
786 | is_mergeable_anon_vma(prev->anon_vma, | |
787 | next->anon_vma)) { | |
788 | /* cases 1, 6 */ | |
789 | vma_adjust(prev, prev->vm_start, | |
790 | next->vm_end, prev->vm_pgoff, NULL); | |
791 | } else /* cases 2, 5, 7 */ | |
792 | vma_adjust(prev, prev->vm_start, | |
793 | end, prev->vm_pgoff, NULL); | |
794 | return prev; | |
795 | } | |
796 | ||
797 | /* | |
798 | * Can this new request be merged in front of next? | |
799 | */ | |
800 | if (next && end == next->vm_start && | |
801 | mpol_equal(policy, vma_policy(next)) && | |
802 | can_vma_merge_before(next, vm_flags, | |
803 | anon_vma, file, pgoff+pglen)) { | |
804 | if (prev && addr < prev->vm_end) /* case 4 */ | |
805 | vma_adjust(prev, prev->vm_start, | |
806 | addr, prev->vm_pgoff, NULL); | |
807 | else /* cases 3, 8 */ | |
808 | vma_adjust(area, addr, next->vm_end, | |
809 | next->vm_pgoff - pglen, NULL); | |
810 | return area; | |
811 | } | |
812 | ||
813 | return NULL; | |
814 | } | |
815 | ||
816 | /* | |
817 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
818 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
819 | * to allocate a new anon_vma. It checks because a repetitive | |
820 | * sequence of mprotects and faults may otherwise lead to distinct | |
821 | * anon_vmas being allocated, preventing vma merge in subsequent | |
822 | * mprotect. | |
823 | */ | |
824 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
825 | { | |
826 | struct vm_area_struct *near; | |
827 | unsigned long vm_flags; | |
828 | ||
829 | near = vma->vm_next; | |
830 | if (!near) | |
831 | goto try_prev; | |
832 | ||
833 | /* | |
834 | * Since only mprotect tries to remerge vmas, match flags | |
835 | * which might be mprotected into each other later on. | |
836 | * Neither mlock nor madvise tries to remerge at present, | |
837 | * so leave their flags as obstructing a merge. | |
838 | */ | |
839 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
840 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
841 | ||
842 | if (near->anon_vma && vma->vm_end == near->vm_start && | |
843 | mpol_equal(vma_policy(vma), vma_policy(near)) && | |
844 | can_vma_merge_before(near, vm_flags, | |
845 | NULL, vma->vm_file, vma->vm_pgoff + | |
846 | ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) | |
847 | return near->anon_vma; | |
848 | try_prev: | |
849 | /* | |
850 | * It is potentially slow to have to call find_vma_prev here. | |
851 | * But it's only on the first write fault on the vma, not | |
852 | * every time, and we could devise a way to avoid it later | |
853 | * (e.g. stash info in next's anon_vma_node when assigning | |
854 | * an anon_vma, or when trying vma_merge). Another time. | |
855 | */ | |
46a350ef | 856 | BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma); |
1da177e4 LT |
857 | if (!near) |
858 | goto none; | |
859 | ||
860 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); | |
861 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); | |
862 | ||
863 | if (near->anon_vma && near->vm_end == vma->vm_start && | |
864 | mpol_equal(vma_policy(near), vma_policy(vma)) && | |
865 | can_vma_merge_after(near, vm_flags, | |
866 | NULL, vma->vm_file, vma->vm_pgoff)) | |
867 | return near->anon_vma; | |
868 | none: | |
869 | /* | |
870 | * There's no absolute need to look only at touching neighbours: | |
871 | * we could search further afield for "compatible" anon_vmas. | |
872 | * But it would probably just be a waste of time searching, | |
873 | * or lead to too many vmas hanging off the same anon_vma. | |
874 | * We're trying to allow mprotect remerging later on, | |
875 | * not trying to minimize memory used for anon_vmas. | |
876 | */ | |
877 | return NULL; | |
878 | } | |
879 | ||
880 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 881 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
882 | struct file *file, long pages) |
883 | { | |
884 | const unsigned long stack_flags | |
885 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
886 | ||
1da177e4 LT |
887 | if (file) { |
888 | mm->shared_vm += pages; | |
889 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
890 | mm->exec_vm += pages; | |
891 | } else if (flags & stack_flags) | |
892 | mm->stack_vm += pages; | |
893 | if (flags & (VM_RESERVED|VM_IO)) | |
894 | mm->reserved_vm += pages; | |
895 | } | |
896 | #endif /* CONFIG_PROC_FS */ | |
897 | ||
898 | /* | |
899 | * The caller must hold down_write(current->mm->mmap_sem). | |
900 | */ | |
901 | ||
902 | unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, | |
903 | unsigned long len, unsigned long prot, | |
904 | unsigned long flags, unsigned long pgoff) | |
905 | { | |
906 | struct mm_struct * mm = current->mm; | |
1da177e4 LT |
907 | struct inode *inode; |
908 | unsigned int vm_flags; | |
1da177e4 | 909 | int error; |
1da177e4 | 910 | int accountable = 1; |
0165ab44 | 911 | unsigned long reqprot = prot; |
1da177e4 | 912 | |
1da177e4 LT |
913 | /* |
914 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
915 | * | |
916 | * (the exception is when the underlying filesystem is noexec | |
917 | * mounted, in which case we dont add PROT_EXEC.) | |
918 | */ | |
919 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 920 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
921 | prot |= PROT_EXEC; |
922 | ||
923 | if (!len) | |
924 | return -EINVAL; | |
925 | ||
7cd94146 EP |
926 | if (!(flags & MAP_FIXED)) |
927 | addr = round_hint_to_min(addr); | |
928 | ||
3a459756 KK |
929 | error = arch_mmap_check(addr, len, flags); |
930 | if (error) | |
931 | return error; | |
932 | ||
1da177e4 LT |
933 | /* Careful about overflows.. */ |
934 | len = PAGE_ALIGN(len); | |
935 | if (!len || len > TASK_SIZE) | |
936 | return -ENOMEM; | |
937 | ||
938 | /* offset overflow? */ | |
939 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
940 | return -EOVERFLOW; | |
941 | ||
942 | /* Too many mappings? */ | |
943 | if (mm->map_count > sysctl_max_map_count) | |
944 | return -ENOMEM; | |
945 | ||
946 | /* Obtain the address to map to. we verify (or select) it and ensure | |
947 | * that it represents a valid section of the address space. | |
948 | */ | |
949 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
950 | if (addr & ~PAGE_MASK) | |
951 | return addr; | |
952 | ||
953 | /* Do simple checking here so the lower-level routines won't have | |
954 | * to. we assume access permissions have been handled by the open | |
955 | * of the memory object, so we don't do any here. | |
956 | */ | |
957 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
958 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
959 | ||
960 | if (flags & MAP_LOCKED) { | |
961 | if (!can_do_mlock()) | |
962 | return -EPERM; | |
963 | vm_flags |= VM_LOCKED; | |
964 | } | |
965 | /* mlock MCL_FUTURE? */ | |
966 | if (vm_flags & VM_LOCKED) { | |
967 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
968 | locked = len >> PAGE_SHIFT; |
969 | locked += mm->locked_vm; | |
1da177e4 | 970 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 971 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
972 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
973 | return -EAGAIN; | |
974 | } | |
975 | ||
d3ac7f89 | 976 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
977 | |
978 | if (file) { | |
979 | switch (flags & MAP_TYPE) { | |
980 | case MAP_SHARED: | |
981 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
982 | return -EACCES; | |
983 | ||
984 | /* | |
985 | * Make sure we don't allow writing to an append-only | |
986 | * file.. | |
987 | */ | |
988 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
989 | return -EACCES; | |
990 | ||
991 | /* | |
992 | * Make sure there are no mandatory locks on the file. | |
993 | */ | |
994 | if (locks_verify_locked(inode)) | |
995 | return -EAGAIN; | |
996 | ||
997 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
998 | if (!(file->f_mode & FMODE_WRITE)) | |
999 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1000 | ||
1001 | /* fall through */ | |
1002 | case MAP_PRIVATE: | |
1003 | if (!(file->f_mode & FMODE_READ)) | |
1004 | return -EACCES; | |
d3ac7f89 | 1005 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1006 | if (vm_flags & VM_EXEC) |
1007 | return -EPERM; | |
1008 | vm_flags &= ~VM_MAYEXEC; | |
1009 | } | |
1010 | if (is_file_hugepages(file)) | |
1011 | accountable = 0; | |
1012 | ||
1013 | if (!file->f_op || !file->f_op->mmap) | |
1014 | return -ENODEV; | |
1da177e4 LT |
1015 | break; |
1016 | ||
1017 | default: | |
1018 | return -EINVAL; | |
1019 | } | |
1020 | } else { | |
1021 | switch (flags & MAP_TYPE) { | |
1022 | case MAP_SHARED: | |
1023 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1024 | break; | |
1025 | case MAP_PRIVATE: | |
1026 | /* | |
1027 | * Set pgoff according to addr for anon_vma. | |
1028 | */ | |
1029 | pgoff = addr >> PAGE_SHIFT; | |
1030 | break; | |
1031 | default: | |
1032 | return -EINVAL; | |
1033 | } | |
1034 | } | |
1035 | ||
ed032189 | 1036 | error = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1da177e4 LT |
1037 | if (error) |
1038 | return error; | |
ed032189 | 1039 | |
0165ab44 MS |
1040 | return mmap_region(file, addr, len, flags, vm_flags, pgoff, |
1041 | accountable); | |
1042 | } | |
1043 | EXPORT_SYMBOL(do_mmap_pgoff); | |
1044 | ||
4e950f6f AD |
1045 | /* |
1046 | * Some shared mappigns will want the pages marked read-only | |
1047 | * to track write events. If so, we'll downgrade vm_page_prot | |
1048 | * to the private version (using protection_map[] without the | |
1049 | * VM_SHARED bit). | |
1050 | */ | |
1051 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1052 | { | |
1053 | unsigned int vm_flags = vma->vm_flags; | |
1054 | ||
1055 | /* If it was private or non-writable, the write bit is already clear */ | |
1056 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1057 | return 0; | |
1058 | ||
1059 | /* The backer wishes to know when pages are first written to? */ | |
1060 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1061 | return 1; | |
1062 | ||
1063 | /* The open routine did something to the protections already? */ | |
1064 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1065 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1066 | return 0; |
1067 | ||
1068 | /* Specialty mapping? */ | |
1069 | if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) | |
1070 | return 0; | |
1071 | ||
1072 | /* Can the mapping track the dirty pages? */ | |
1073 | return vma->vm_file && vma->vm_file->f_mapping && | |
1074 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1075 | } | |
1076 | ||
0165ab44 MS |
1077 | unsigned long mmap_region(struct file *file, unsigned long addr, |
1078 | unsigned long len, unsigned long flags, | |
1079 | unsigned int vm_flags, unsigned long pgoff, | |
1080 | int accountable) | |
1081 | { | |
1082 | struct mm_struct *mm = current->mm; | |
1083 | struct vm_area_struct *vma, *prev; | |
1084 | int correct_wcount = 0; | |
1085 | int error; | |
1086 | struct rb_node **rb_link, *rb_parent; | |
1087 | unsigned long charged = 0; | |
1088 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; | |
1089 | ||
1da177e4 LT |
1090 | /* Clear old maps */ |
1091 | error = -ENOMEM; | |
1092 | munmap_back: | |
1093 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1094 | if (vma && vma->vm_start < addr + len) { | |
1095 | if (do_munmap(mm, addr, len)) | |
1096 | return -ENOMEM; | |
1097 | goto munmap_back; | |
1098 | } | |
1099 | ||
1100 | /* Check against address space limit. */ | |
119f657c | 1101 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1102 | return -ENOMEM; |
1103 | ||
1104 | if (accountable && (!(flags & MAP_NORESERVE) || | |
1105 | sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { | |
1106 | if (vm_flags & VM_SHARED) { | |
1107 | /* Check memory availability in shmem_file_setup? */ | |
1108 | vm_flags |= VM_ACCOUNT; | |
1109 | } else if (vm_flags & VM_WRITE) { | |
1110 | /* | |
1111 | * Private writable mapping: check memory availability | |
1112 | */ | |
1113 | charged = len >> PAGE_SHIFT; | |
1114 | if (security_vm_enough_memory(charged)) | |
1115 | return -ENOMEM; | |
1116 | vm_flags |= VM_ACCOUNT; | |
1117 | } | |
1118 | } | |
1119 | ||
1120 | /* | |
1121 | * Can we just expand an old private anonymous mapping? | |
1122 | * The VM_SHARED test is necessary because shmem_zero_setup | |
1123 | * will create the file object for a shared anonymous map below. | |
1124 | */ | |
1125 | if (!file && !(vm_flags & VM_SHARED) && | |
1126 | vma_merge(mm, prev, addr, addr + len, vm_flags, | |
1127 | NULL, NULL, pgoff, NULL)) | |
1128 | goto out; | |
1129 | ||
1130 | /* | |
1131 | * Determine the object being mapped and call the appropriate | |
1132 | * specific mapper. the address has already been validated, but | |
1133 | * not unmapped, but the maps are removed from the list. | |
1134 | */ | |
c5e3b83e | 1135 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1136 | if (!vma) { |
1137 | error = -ENOMEM; | |
1138 | goto unacct_error; | |
1139 | } | |
1da177e4 LT |
1140 | |
1141 | vma->vm_mm = mm; | |
1142 | vma->vm_start = addr; | |
1143 | vma->vm_end = addr + len; | |
1144 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1145 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 LT |
1146 | vma->vm_pgoff = pgoff; |
1147 | ||
1148 | if (file) { | |
1149 | error = -EINVAL; | |
1150 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) | |
1151 | goto free_vma; | |
1152 | if (vm_flags & VM_DENYWRITE) { | |
1153 | error = deny_write_access(file); | |
1154 | if (error) | |
1155 | goto free_vma; | |
1156 | correct_wcount = 1; | |
1157 | } | |
1158 | vma->vm_file = file; | |
1159 | get_file(file); | |
1160 | error = file->f_op->mmap(file, vma); | |
1161 | if (error) | |
1162 | goto unmap_and_free_vma; | |
925d1c40 MH |
1163 | if (vm_flags & VM_EXECUTABLE) |
1164 | added_exe_file_vma(mm); | |
1da177e4 LT |
1165 | } else if (vm_flags & VM_SHARED) { |
1166 | error = shmem_zero_setup(vma); | |
1167 | if (error) | |
1168 | goto free_vma; | |
1169 | } | |
1170 | ||
1171 | /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform | |
1172 | * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) | |
1173 | * that memory reservation must be checked; but that reservation | |
1174 | * belongs to shared memory object, not to vma: so now clear it. | |
1175 | */ | |
1176 | if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) | |
1177 | vma->vm_flags &= ~VM_ACCOUNT; | |
1178 | ||
1179 | /* Can addr have changed?? | |
1180 | * | |
1181 | * Answer: Yes, several device drivers can do it in their | |
1182 | * f_op->mmap method. -DaveM | |
1183 | */ | |
1184 | addr = vma->vm_start; | |
1185 | pgoff = vma->vm_pgoff; | |
1186 | vm_flags = vma->vm_flags; | |
1187 | ||
d08b3851 | 1188 | if (vma_wants_writenotify(vma)) |
1ddd439e | 1189 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
d08b3851 | 1190 | |
4d3d5b41 | 1191 | if (file && vma_merge(mm, prev, addr, vma->vm_end, |
1da177e4 | 1192 | vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { |
f0be3d32 | 1193 | mpol_put(vma_policy(vma)); |
1da177e4 | 1194 | kmem_cache_free(vm_area_cachep, vma); |
4d3d5b41 | 1195 | fput(file); |
925d1c40 MH |
1196 | if (vm_flags & VM_EXECUTABLE) |
1197 | removed_exe_file_vma(mm); | |
4d3d5b41 ON |
1198 | } else { |
1199 | vma_link(mm, vma, prev, rb_link, rb_parent); | |
1200 | file = vma->vm_file; | |
1da177e4 | 1201 | } |
4d3d5b41 ON |
1202 | |
1203 | /* Once vma denies write, undo our temporary denial count */ | |
1204 | if (correct_wcount) | |
1205 | atomic_inc(&inode->i_writecount); | |
1206 | out: | |
1da177e4 | 1207 | mm->total_vm += len >> PAGE_SHIFT; |
ab50b8ed | 1208 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 LT |
1209 | if (vm_flags & VM_LOCKED) { |
1210 | mm->locked_vm += len >> PAGE_SHIFT; | |
1211 | make_pages_present(addr, addr + len); | |
1212 | } | |
54cb8821 NP |
1213 | if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
1214 | make_pages_present(addr, addr + len); | |
1da177e4 LT |
1215 | return addr; |
1216 | ||
1217 | unmap_and_free_vma: | |
1218 | if (correct_wcount) | |
1219 | atomic_inc(&inode->i_writecount); | |
1220 | vma->vm_file = NULL; | |
1221 | fput(file); | |
1222 | ||
1223 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1224 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1225 | charged = 0; | |
1da177e4 LT |
1226 | free_vma: |
1227 | kmem_cache_free(vm_area_cachep, vma); | |
1228 | unacct_error: | |
1229 | if (charged) | |
1230 | vm_unacct_memory(charged); | |
1231 | return error; | |
1232 | } | |
1233 | ||
1da177e4 LT |
1234 | /* Get an address range which is currently unmapped. |
1235 | * For shmat() with addr=0. | |
1236 | * | |
1237 | * Ugly calling convention alert: | |
1238 | * Return value with the low bits set means error value, | |
1239 | * ie | |
1240 | * if (ret & ~PAGE_MASK) | |
1241 | * error = ret; | |
1242 | * | |
1243 | * This function "knows" that -ENOMEM has the bits set. | |
1244 | */ | |
1245 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1246 | unsigned long | |
1247 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1248 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1249 | { | |
1250 | struct mm_struct *mm = current->mm; | |
1251 | struct vm_area_struct *vma; | |
1252 | unsigned long start_addr; | |
1253 | ||
1254 | if (len > TASK_SIZE) | |
1255 | return -ENOMEM; | |
1256 | ||
06abdfb4 BH |
1257 | if (flags & MAP_FIXED) |
1258 | return addr; | |
1259 | ||
1da177e4 LT |
1260 | if (addr) { |
1261 | addr = PAGE_ALIGN(addr); | |
1262 | vma = find_vma(mm, addr); | |
1263 | if (TASK_SIZE - len >= addr && | |
1264 | (!vma || addr + len <= vma->vm_start)) | |
1265 | return addr; | |
1266 | } | |
1363c3cd WW |
1267 | if (len > mm->cached_hole_size) { |
1268 | start_addr = addr = mm->free_area_cache; | |
1269 | } else { | |
1270 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1271 | mm->cached_hole_size = 0; | |
1272 | } | |
1da177e4 LT |
1273 | |
1274 | full_search: | |
1275 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1276 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1277 | if (TASK_SIZE - len < addr) { | |
1278 | /* | |
1279 | * Start a new search - just in case we missed | |
1280 | * some holes. | |
1281 | */ | |
1282 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1283 | addr = TASK_UNMAPPED_BASE; |
1284 | start_addr = addr; | |
1285 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1286 | goto full_search; |
1287 | } | |
1288 | return -ENOMEM; | |
1289 | } | |
1290 | if (!vma || addr + len <= vma->vm_start) { | |
1291 | /* | |
1292 | * Remember the place where we stopped the search: | |
1293 | */ | |
1294 | mm->free_area_cache = addr + len; | |
1295 | return addr; | |
1296 | } | |
1363c3cd WW |
1297 | if (addr + mm->cached_hole_size < vma->vm_start) |
1298 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1299 | addr = vma->vm_end; |
1300 | } | |
1301 | } | |
1302 | #endif | |
1303 | ||
1363c3cd | 1304 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1305 | { |
1306 | /* | |
1307 | * Is this a new hole at the lowest possible address? | |
1308 | */ | |
1363c3cd WW |
1309 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { |
1310 | mm->free_area_cache = addr; | |
1311 | mm->cached_hole_size = ~0UL; | |
1312 | } | |
1da177e4 LT |
1313 | } |
1314 | ||
1315 | /* | |
1316 | * This mmap-allocator allocates new areas top-down from below the | |
1317 | * stack's low limit (the base): | |
1318 | */ | |
1319 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1320 | unsigned long | |
1321 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1322 | const unsigned long len, const unsigned long pgoff, | |
1323 | const unsigned long flags) | |
1324 | { | |
1325 | struct vm_area_struct *vma; | |
1326 | struct mm_struct *mm = current->mm; | |
1327 | unsigned long addr = addr0; | |
1328 | ||
1329 | /* requested length too big for entire address space */ | |
1330 | if (len > TASK_SIZE) | |
1331 | return -ENOMEM; | |
1332 | ||
06abdfb4 BH |
1333 | if (flags & MAP_FIXED) |
1334 | return addr; | |
1335 | ||
1da177e4 LT |
1336 | /* requesting a specific address */ |
1337 | if (addr) { | |
1338 | addr = PAGE_ALIGN(addr); | |
1339 | vma = find_vma(mm, addr); | |
1340 | if (TASK_SIZE - len >= addr && | |
1341 | (!vma || addr + len <= vma->vm_start)) | |
1342 | return addr; | |
1343 | } | |
1344 | ||
1363c3cd WW |
1345 | /* check if free_area_cache is useful for us */ |
1346 | if (len <= mm->cached_hole_size) { | |
1347 | mm->cached_hole_size = 0; | |
1348 | mm->free_area_cache = mm->mmap_base; | |
1349 | } | |
1350 | ||
1da177e4 LT |
1351 | /* either no address requested or can't fit in requested address hole */ |
1352 | addr = mm->free_area_cache; | |
1353 | ||
1354 | /* make sure it can fit in the remaining address space */ | |
49a43876 | 1355 | if (addr > len) { |
1da177e4 LT |
1356 | vma = find_vma(mm, addr-len); |
1357 | if (!vma || addr <= vma->vm_start) | |
1358 | /* remember the address as a hint for next time */ | |
1359 | return (mm->free_area_cache = addr-len); | |
1360 | } | |
1361 | ||
73219d17 CW |
1362 | if (mm->mmap_base < len) |
1363 | goto bottomup; | |
1364 | ||
1da177e4 LT |
1365 | addr = mm->mmap_base-len; |
1366 | ||
1367 | do { | |
1368 | /* | |
1369 | * Lookup failure means no vma is above this address, | |
1370 | * else if new region fits below vma->vm_start, | |
1371 | * return with success: | |
1372 | */ | |
1373 | vma = find_vma(mm, addr); | |
1374 | if (!vma || addr+len <= vma->vm_start) | |
1375 | /* remember the address as a hint for next time */ | |
1376 | return (mm->free_area_cache = addr); | |
1377 | ||
1363c3cd WW |
1378 | /* remember the largest hole we saw so far */ |
1379 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1380 | mm->cached_hole_size = vma->vm_start - addr; | |
1381 | ||
1da177e4 LT |
1382 | /* try just below the current vma->vm_start */ |
1383 | addr = vma->vm_start-len; | |
49a43876 | 1384 | } while (len < vma->vm_start); |
1da177e4 | 1385 | |
73219d17 | 1386 | bottomup: |
1da177e4 LT |
1387 | /* |
1388 | * A failed mmap() very likely causes application failure, | |
1389 | * so fall back to the bottom-up function here. This scenario | |
1390 | * can happen with large stack limits and large mmap() | |
1391 | * allocations. | |
1392 | */ | |
1363c3cd WW |
1393 | mm->cached_hole_size = ~0UL; |
1394 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1395 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1396 | /* | |
1397 | * Restore the topdown base: | |
1398 | */ | |
1399 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1400 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1401 | |
1402 | return addr; | |
1403 | } | |
1404 | #endif | |
1405 | ||
1363c3cd | 1406 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1407 | { |
1408 | /* | |
1409 | * Is this a new hole at the highest possible address? | |
1410 | */ | |
1363c3cd WW |
1411 | if (addr > mm->free_area_cache) |
1412 | mm->free_area_cache = addr; | |
1da177e4 LT |
1413 | |
1414 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1415 | if (mm->free_area_cache > mm->mmap_base) |
1416 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1417 | } |
1418 | ||
1419 | unsigned long | |
1420 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1421 | unsigned long pgoff, unsigned long flags) | |
1422 | { | |
06abdfb4 BH |
1423 | unsigned long (*get_area)(struct file *, unsigned long, |
1424 | unsigned long, unsigned long, unsigned long); | |
1425 | ||
1426 | get_area = current->mm->get_unmapped_area; | |
1427 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1428 | get_area = file->f_op->get_unmapped_area; | |
1429 | addr = get_area(file, addr, len, pgoff, flags); | |
1430 | if (IS_ERR_VALUE(addr)) | |
1431 | return addr; | |
1da177e4 | 1432 | |
07ab67c8 LT |
1433 | if (addr > TASK_SIZE - len) |
1434 | return -ENOMEM; | |
1435 | if (addr & ~PAGE_MASK) | |
1436 | return -EINVAL; | |
06abdfb4 | 1437 | |
08e7d9b5 | 1438 | return arch_rebalance_pgtables(addr, len); |
1da177e4 LT |
1439 | } |
1440 | ||
1441 | EXPORT_SYMBOL(get_unmapped_area); | |
1442 | ||
1443 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
1444 | struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) | |
1445 | { | |
1446 | struct vm_area_struct *vma = NULL; | |
1447 | ||
1448 | if (mm) { | |
1449 | /* Check the cache first. */ | |
1450 | /* (Cache hit rate is typically around 35%.) */ | |
1451 | vma = mm->mmap_cache; | |
1452 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1453 | struct rb_node * rb_node; | |
1454 | ||
1455 | rb_node = mm->mm_rb.rb_node; | |
1456 | vma = NULL; | |
1457 | ||
1458 | while (rb_node) { | |
1459 | struct vm_area_struct * vma_tmp; | |
1460 | ||
1461 | vma_tmp = rb_entry(rb_node, | |
1462 | struct vm_area_struct, vm_rb); | |
1463 | ||
1464 | if (vma_tmp->vm_end > addr) { | |
1465 | vma = vma_tmp; | |
1466 | if (vma_tmp->vm_start <= addr) | |
1467 | break; | |
1468 | rb_node = rb_node->rb_left; | |
1469 | } else | |
1470 | rb_node = rb_node->rb_right; | |
1471 | } | |
1472 | if (vma) | |
1473 | mm->mmap_cache = vma; | |
1474 | } | |
1475 | } | |
1476 | return vma; | |
1477 | } | |
1478 | ||
1479 | EXPORT_SYMBOL(find_vma); | |
1480 | ||
1481 | /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ | |
1482 | struct vm_area_struct * | |
1483 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1484 | struct vm_area_struct **pprev) | |
1485 | { | |
1486 | struct vm_area_struct *vma = NULL, *prev = NULL; | |
1487 | struct rb_node * rb_node; | |
1488 | if (!mm) | |
1489 | goto out; | |
1490 | ||
1491 | /* Guard against addr being lower than the first VMA */ | |
1492 | vma = mm->mmap; | |
1493 | ||
1494 | /* Go through the RB tree quickly. */ | |
1495 | rb_node = mm->mm_rb.rb_node; | |
1496 | ||
1497 | while (rb_node) { | |
1498 | struct vm_area_struct *vma_tmp; | |
1499 | vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1500 | ||
1501 | if (addr < vma_tmp->vm_end) { | |
1502 | rb_node = rb_node->rb_left; | |
1503 | } else { | |
1504 | prev = vma_tmp; | |
1505 | if (!prev->vm_next || (addr < prev->vm_next->vm_end)) | |
1506 | break; | |
1507 | rb_node = rb_node->rb_right; | |
1508 | } | |
1509 | } | |
1510 | ||
1511 | out: | |
1512 | *pprev = prev; | |
1513 | return prev ? prev->vm_next : vma; | |
1514 | } | |
1515 | ||
1516 | /* | |
1517 | * Verify that the stack growth is acceptable and | |
1518 | * update accounting. This is shared with both the | |
1519 | * grow-up and grow-down cases. | |
1520 | */ | |
1521 | static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) | |
1522 | { | |
1523 | struct mm_struct *mm = vma->vm_mm; | |
1524 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1525 | unsigned long new_start; |
1da177e4 LT |
1526 | |
1527 | /* address space limit tests */ | |
119f657c | 1528 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1529 | return -ENOMEM; |
1530 | ||
1531 | /* Stack limit test */ | |
1532 | if (size > rlim[RLIMIT_STACK].rlim_cur) | |
1533 | return -ENOMEM; | |
1534 | ||
1535 | /* mlock limit tests */ | |
1536 | if (vma->vm_flags & VM_LOCKED) { | |
1537 | unsigned long locked; | |
1538 | unsigned long limit; | |
1539 | locked = mm->locked_vm + grow; | |
1540 | limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; | |
1541 | if (locked > limit && !capable(CAP_IPC_LOCK)) | |
1542 | return -ENOMEM; | |
1543 | } | |
1544 | ||
0d59a01b AL |
1545 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1546 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1547 | vma->vm_end - size; | |
1548 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1549 | return -EFAULT; | |
1550 | ||
1da177e4 LT |
1551 | /* |
1552 | * Overcommit.. This must be the final test, as it will | |
1553 | * update security statistics. | |
1554 | */ | |
1555 | if (security_vm_enough_memory(grow)) | |
1556 | return -ENOMEM; | |
1557 | ||
1558 | /* Ok, everything looks good - let it rip */ | |
1559 | mm->total_vm += grow; | |
1560 | if (vma->vm_flags & VM_LOCKED) | |
1561 | mm->locked_vm += grow; | |
ab50b8ed | 1562 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1563 | return 0; |
1564 | } | |
1565 | ||
46dea3d0 | 1566 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1567 | /* |
46dea3d0 HD |
1568 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1569 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1570 | */ |
9ab88515 | 1571 | #ifndef CONFIG_IA64 |
46dea3d0 HD |
1572 | static inline |
1573 | #endif | |
1574 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) | |
1da177e4 LT |
1575 | { |
1576 | int error; | |
1577 | ||
1578 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1579 | return -EFAULT; | |
1580 | ||
1581 | /* | |
1582 | * We must make sure the anon_vma is allocated | |
1583 | * so that the anon_vma locking is not a noop. | |
1584 | */ | |
1585 | if (unlikely(anon_vma_prepare(vma))) | |
1586 | return -ENOMEM; | |
1587 | anon_vma_lock(vma); | |
1588 | ||
1589 | /* | |
1590 | * vma->vm_start/vm_end cannot change under us because the caller | |
1591 | * is required to hold the mmap_sem in read mode. We need the | |
1592 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 1593 | * Also guard against wrapping around to address 0. |
1da177e4 | 1594 | */ |
06b32f3a HD |
1595 | if (address < PAGE_ALIGN(address+4)) |
1596 | address = PAGE_ALIGN(address+4); | |
1597 | else { | |
1598 | anon_vma_unlock(vma); | |
1599 | return -ENOMEM; | |
1600 | } | |
1da177e4 LT |
1601 | error = 0; |
1602 | ||
1603 | /* Somebody else might have raced and expanded it already */ | |
1604 | if (address > vma->vm_end) { | |
1605 | unsigned long size, grow; | |
1606 | ||
1607 | size = address - vma->vm_start; | |
1608 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1609 | ||
1610 | error = acct_stack_growth(vma, size, grow); | |
1611 | if (!error) | |
1612 | vma->vm_end = address; | |
1613 | } | |
1614 | anon_vma_unlock(vma); | |
1615 | return error; | |
1616 | } | |
46dea3d0 HD |
1617 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1618 | ||
1da177e4 LT |
1619 | /* |
1620 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1621 | */ | |
b6a2fea3 OW |
1622 | static inline int expand_downwards(struct vm_area_struct *vma, |
1623 | unsigned long address) | |
1da177e4 LT |
1624 | { |
1625 | int error; | |
1626 | ||
1627 | /* | |
1628 | * We must make sure the anon_vma is allocated | |
1629 | * so that the anon_vma locking is not a noop. | |
1630 | */ | |
1631 | if (unlikely(anon_vma_prepare(vma))) | |
1632 | return -ENOMEM; | |
8869477a EP |
1633 | |
1634 | address &= PAGE_MASK; | |
88c3f7a8 | 1635 | error = security_file_mmap(NULL, 0, 0, 0, address, 1); |
8869477a EP |
1636 | if (error) |
1637 | return error; | |
1638 | ||
1da177e4 LT |
1639 | anon_vma_lock(vma); |
1640 | ||
1641 | /* | |
1642 | * vma->vm_start/vm_end cannot change under us because the caller | |
1643 | * is required to hold the mmap_sem in read mode. We need the | |
1644 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1645 | */ | |
1da177e4 LT |
1646 | |
1647 | /* Somebody else might have raced and expanded it already */ | |
1648 | if (address < vma->vm_start) { | |
1649 | unsigned long size, grow; | |
1650 | ||
1651 | size = vma->vm_end - address; | |
1652 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1653 | ||
1654 | error = acct_stack_growth(vma, size, grow); | |
1655 | if (!error) { | |
1656 | vma->vm_start = address; | |
1657 | vma->vm_pgoff -= grow; | |
1658 | } | |
1659 | } | |
1660 | anon_vma_unlock(vma); | |
1661 | return error; | |
1662 | } | |
1663 | ||
b6a2fea3 OW |
1664 | int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address) |
1665 | { | |
1666 | return expand_downwards(vma, address); | |
1667 | } | |
1668 | ||
1669 | #ifdef CONFIG_STACK_GROWSUP | |
1670 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1671 | { | |
1672 | return expand_upwards(vma, address); | |
1673 | } | |
1674 | ||
1675 | struct vm_area_struct * | |
1676 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1677 | { | |
1678 | struct vm_area_struct *vma, *prev; | |
1679 | ||
1680 | addr &= PAGE_MASK; | |
1681 | vma = find_vma_prev(mm, addr, &prev); | |
1682 | if (vma && (vma->vm_start <= addr)) | |
1683 | return vma; | |
1684 | if (!prev || expand_stack(prev, addr)) | |
1685 | return NULL; | |
1686 | if (prev->vm_flags & VM_LOCKED) | |
1687 | make_pages_present(addr, prev->vm_end); | |
1688 | return prev; | |
1689 | } | |
1690 | #else | |
1691 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1692 | { | |
1693 | return expand_downwards(vma, address); | |
1694 | } | |
1695 | ||
1da177e4 LT |
1696 | struct vm_area_struct * |
1697 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1698 | { | |
1699 | struct vm_area_struct * vma; | |
1700 | unsigned long start; | |
1701 | ||
1702 | addr &= PAGE_MASK; | |
1703 | vma = find_vma(mm,addr); | |
1704 | if (!vma) | |
1705 | return NULL; | |
1706 | if (vma->vm_start <= addr) | |
1707 | return vma; | |
1708 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1709 | return NULL; | |
1710 | start = vma->vm_start; | |
1711 | if (expand_stack(vma, addr)) | |
1712 | return NULL; | |
b6a2fea3 | 1713 | if (vma->vm_flags & VM_LOCKED) |
1da177e4 | 1714 | make_pages_present(addr, start); |
1da177e4 LT |
1715 | return vma; |
1716 | } | |
1717 | #endif | |
1718 | ||
1da177e4 | 1719 | /* |
2c0b3814 | 1720 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1721 | * so release them, and do the vma updates. |
2c0b3814 HD |
1722 | * |
1723 | * Called with the mm semaphore held. | |
1da177e4 | 1724 | */ |
2c0b3814 | 1725 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1726 | { |
365e9c87 HD |
1727 | /* Update high watermark before we lower total_vm */ |
1728 | update_hiwater_vm(mm); | |
1da177e4 | 1729 | do { |
2c0b3814 HD |
1730 | long nrpages = vma_pages(vma); |
1731 | ||
1732 | mm->total_vm -= nrpages; | |
1733 | if (vma->vm_flags & VM_LOCKED) | |
1734 | mm->locked_vm -= nrpages; | |
1735 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); | |
a8fb5618 | 1736 | vma = remove_vma(vma); |
146425a3 | 1737 | } while (vma); |
1da177e4 LT |
1738 | validate_mm(mm); |
1739 | } | |
1740 | ||
1741 | /* | |
1742 | * Get rid of page table information in the indicated region. | |
1743 | * | |
f10df686 | 1744 | * Called with the mm semaphore held. |
1da177e4 LT |
1745 | */ |
1746 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1747 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1748 | unsigned long start, unsigned long end) | |
1da177e4 | 1749 | { |
e0da382c | 1750 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
1da177e4 LT |
1751 | struct mmu_gather *tlb; |
1752 | unsigned long nr_accounted = 0; | |
1753 | ||
1754 | lru_add_drain(); | |
1755 | tlb = tlb_gather_mmu(mm, 0); | |
365e9c87 | 1756 | update_hiwater_rss(mm); |
508034a3 | 1757 | unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); |
1da177e4 | 1758 | vm_unacct_memory(nr_accounted); |
e2cdef8c | 1759 | free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, |
e0da382c | 1760 | next? next->vm_start: 0); |
1da177e4 LT |
1761 | tlb_finish_mmu(tlb, start, end); |
1762 | } | |
1763 | ||
1764 | /* | |
1765 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1766 | * vma list as we go.. | |
1767 | */ | |
1768 | static void | |
1769 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1770 | struct vm_area_struct *prev, unsigned long end) | |
1771 | { | |
1772 | struct vm_area_struct **insertion_point; | |
1773 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1774 | unsigned long addr; |
1da177e4 LT |
1775 | |
1776 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
1777 | do { | |
1778 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1779 | mm->map_count--; | |
1780 | tail_vma = vma; | |
1781 | vma = vma->vm_next; | |
1782 | } while (vma && vma->vm_start < end); | |
1783 | *insertion_point = vma; | |
1784 | tail_vma->vm_next = NULL; | |
1363c3cd WW |
1785 | if (mm->unmap_area == arch_unmap_area) |
1786 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1787 | else | |
1788 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1789 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1790 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1791 | } | |
1792 | ||
1793 | /* | |
1794 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
59c51591 | 1795 | * either for the first part or the tail. |
1da177e4 LT |
1796 | */ |
1797 | int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, | |
1798 | unsigned long addr, int new_below) | |
1799 | { | |
1800 | struct mempolicy *pol; | |
1801 | struct vm_area_struct *new; | |
1802 | ||
1803 | if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) | |
1804 | return -EINVAL; | |
1805 | ||
1806 | if (mm->map_count >= sysctl_max_map_count) | |
1807 | return -ENOMEM; | |
1808 | ||
e94b1766 | 1809 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1810 | if (!new) |
1811 | return -ENOMEM; | |
1812 | ||
1813 | /* most fields are the same, copy all, and then fixup */ | |
1814 | *new = *vma; | |
1815 | ||
1816 | if (new_below) | |
1817 | new->vm_end = addr; | |
1818 | else { | |
1819 | new->vm_start = addr; | |
1820 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
1821 | } | |
1822 | ||
846a16bf | 1823 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 LT |
1824 | if (IS_ERR(pol)) { |
1825 | kmem_cache_free(vm_area_cachep, new); | |
1826 | return PTR_ERR(pol); | |
1827 | } | |
1828 | vma_set_policy(new, pol); | |
1829 | ||
925d1c40 | 1830 | if (new->vm_file) { |
1da177e4 | 1831 | get_file(new->vm_file); |
925d1c40 MH |
1832 | if (vma->vm_flags & VM_EXECUTABLE) |
1833 | added_exe_file_vma(mm); | |
1834 | } | |
1da177e4 LT |
1835 | |
1836 | if (new->vm_ops && new->vm_ops->open) | |
1837 | new->vm_ops->open(new); | |
1838 | ||
1839 | if (new_below) | |
1840 | vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + | |
1841 | ((addr - new->vm_start) >> PAGE_SHIFT), new); | |
1842 | else | |
1843 | vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); | |
1844 | ||
1845 | return 0; | |
1846 | } | |
1847 | ||
1848 | /* Munmap is split into 2 main parts -- this part which finds | |
1849 | * what needs doing, and the areas themselves, which do the | |
1850 | * work. This now handles partial unmappings. | |
1851 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
1852 | */ | |
1853 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
1854 | { | |
1855 | unsigned long end; | |
146425a3 | 1856 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
1857 | |
1858 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
1859 | return -EINVAL; | |
1860 | ||
1861 | if ((len = PAGE_ALIGN(len)) == 0) | |
1862 | return -EINVAL; | |
1863 | ||
1864 | /* Find the first overlapping VMA */ | |
146425a3 HD |
1865 | vma = find_vma_prev(mm, start, &prev); |
1866 | if (!vma) | |
1da177e4 | 1867 | return 0; |
146425a3 | 1868 | /* we have start < vma->vm_end */ |
1da177e4 LT |
1869 | |
1870 | /* if it doesn't overlap, we have nothing.. */ | |
1871 | end = start + len; | |
146425a3 | 1872 | if (vma->vm_start >= end) |
1da177e4 LT |
1873 | return 0; |
1874 | ||
1875 | /* | |
1876 | * If we need to split any vma, do it now to save pain later. | |
1877 | * | |
1878 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
1879 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
1880 | * places tmp vma above, and higher split_vma places tmp vma below. | |
1881 | */ | |
146425a3 HD |
1882 | if (start > vma->vm_start) { |
1883 | int error = split_vma(mm, vma, start, 0); | |
1da177e4 LT |
1884 | if (error) |
1885 | return error; | |
146425a3 | 1886 | prev = vma; |
1da177e4 LT |
1887 | } |
1888 | ||
1889 | /* Does it split the last one? */ | |
1890 | last = find_vma(mm, end); | |
1891 | if (last && end > last->vm_start) { | |
1892 | int error = split_vma(mm, last, end, 1); | |
1893 | if (error) | |
1894 | return error; | |
1895 | } | |
146425a3 | 1896 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 LT |
1897 | |
1898 | /* | |
1899 | * Remove the vma's, and unmap the actual pages | |
1900 | */ | |
146425a3 HD |
1901 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
1902 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
1903 | |
1904 | /* Fix up all other VM information */ | |
2c0b3814 | 1905 | remove_vma_list(mm, vma); |
1da177e4 LT |
1906 | |
1907 | return 0; | |
1908 | } | |
1909 | ||
1910 | EXPORT_SYMBOL(do_munmap); | |
1911 | ||
1912 | asmlinkage long sys_munmap(unsigned long addr, size_t len) | |
1913 | { | |
1914 | int ret; | |
1915 | struct mm_struct *mm = current->mm; | |
1916 | ||
1917 | profile_munmap(addr); | |
1918 | ||
1919 | down_write(&mm->mmap_sem); | |
1920 | ret = do_munmap(mm, addr, len); | |
1921 | up_write(&mm->mmap_sem); | |
1922 | return ret; | |
1923 | } | |
1924 | ||
1925 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
1926 | { | |
a241ec65 | 1927 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
1928 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
1929 | WARN_ON(1); | |
1930 | up_read(&mm->mmap_sem); | |
1931 | } | |
1932 | #endif | |
1933 | } | |
1934 | ||
1935 | /* | |
1936 | * this is really a simplified "do_mmap". it only handles | |
1937 | * anonymous maps. eventually we may be able to do some | |
1938 | * brk-specific accounting here. | |
1939 | */ | |
1940 | unsigned long do_brk(unsigned long addr, unsigned long len) | |
1941 | { | |
1942 | struct mm_struct * mm = current->mm; | |
1943 | struct vm_area_struct * vma, * prev; | |
1944 | unsigned long flags; | |
1945 | struct rb_node ** rb_link, * rb_parent; | |
1946 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 1947 | int error; |
1da177e4 LT |
1948 | |
1949 | len = PAGE_ALIGN(len); | |
1950 | if (!len) | |
1951 | return addr; | |
1952 | ||
1953 | if ((addr + len) > TASK_SIZE || (addr + len) < addr) | |
1954 | return -EINVAL; | |
1955 | ||
cd2579d7 HD |
1956 | if (is_hugepage_only_range(mm, addr, len)) |
1957 | return -EINVAL; | |
cb07c9a1 | 1958 | |
88c3f7a8 | 1959 | error = security_file_mmap(NULL, 0, 0, 0, addr, 1); |
5a211a5d EP |
1960 | if (error) |
1961 | return error; | |
1962 | ||
3a459756 KK |
1963 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
1964 | ||
1965 | error = arch_mmap_check(addr, len, flags); | |
1966 | if (error) | |
1967 | return error; | |
1968 | ||
1da177e4 LT |
1969 | /* |
1970 | * mlock MCL_FUTURE? | |
1971 | */ | |
1972 | if (mm->def_flags & VM_LOCKED) { | |
1973 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
1974 | locked = len >> PAGE_SHIFT; |
1975 | locked += mm->locked_vm; | |
1da177e4 | 1976 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
93ea1d0a | 1977 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
1978 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1979 | return -EAGAIN; | |
1980 | } | |
1981 | ||
1982 | /* | |
1983 | * mm->mmap_sem is required to protect against another thread | |
1984 | * changing the mappings in case we sleep. | |
1985 | */ | |
1986 | verify_mm_writelocked(mm); | |
1987 | ||
1988 | /* | |
1989 | * Clear old maps. this also does some error checking for us | |
1990 | */ | |
1991 | munmap_back: | |
1992 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1993 | if (vma && vma->vm_start < addr + len) { | |
1994 | if (do_munmap(mm, addr, len)) | |
1995 | return -ENOMEM; | |
1996 | goto munmap_back; | |
1997 | } | |
1998 | ||
1999 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2000 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2001 | return -ENOMEM; |
2002 | ||
2003 | if (mm->map_count > sysctl_max_map_count) | |
2004 | return -ENOMEM; | |
2005 | ||
2006 | if (security_vm_enough_memory(len >> PAGE_SHIFT)) | |
2007 | return -ENOMEM; | |
2008 | ||
1da177e4 LT |
2009 | /* Can we just expand an old private anonymous mapping? */ |
2010 | if (vma_merge(mm, prev, addr, addr + len, flags, | |
2011 | NULL, NULL, pgoff, NULL)) | |
2012 | goto out; | |
2013 | ||
2014 | /* | |
2015 | * create a vma struct for an anonymous mapping | |
2016 | */ | |
c5e3b83e | 2017 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2018 | if (!vma) { |
2019 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2020 | return -ENOMEM; | |
2021 | } | |
1da177e4 LT |
2022 | |
2023 | vma->vm_mm = mm; | |
2024 | vma->vm_start = addr; | |
2025 | vma->vm_end = addr + len; | |
2026 | vma->vm_pgoff = pgoff; | |
2027 | vma->vm_flags = flags; | |
3ed75eb8 | 2028 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2029 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2030 | out: | |
2031 | mm->total_vm += len >> PAGE_SHIFT; | |
2032 | if (flags & VM_LOCKED) { | |
2033 | mm->locked_vm += len >> PAGE_SHIFT; | |
2034 | make_pages_present(addr, addr + len); | |
2035 | } | |
2036 | return addr; | |
2037 | } | |
2038 | ||
2039 | EXPORT_SYMBOL(do_brk); | |
2040 | ||
2041 | /* Release all mmaps. */ | |
2042 | void exit_mmap(struct mm_struct *mm) | |
2043 | { | |
2044 | struct mmu_gather *tlb; | |
e0da382c | 2045 | struct vm_area_struct *vma = mm->mmap; |
1da177e4 | 2046 | unsigned long nr_accounted = 0; |
ee39b37b | 2047 | unsigned long end; |
1da177e4 | 2048 | |
d6dd61c8 JF |
2049 | /* mm's last user has gone, and its about to be pulled down */ |
2050 | arch_exit_mmap(mm); | |
2051 | ||
1da177e4 | 2052 | lru_add_drain(); |
1da177e4 | 2053 | flush_cache_mm(mm); |
e0da382c | 2054 | tlb = tlb_gather_mmu(mm, 1); |
365e9c87 | 2055 | /* Don't update_hiwater_rss(mm) here, do_exit already did */ |
e0da382c | 2056 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
508034a3 | 2057 | end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); |
1da177e4 | 2058 | vm_unacct_memory(nr_accounted); |
e2cdef8c | 2059 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
ee39b37b | 2060 | tlb_finish_mmu(tlb, 0, end); |
1da177e4 | 2061 | |
1da177e4 | 2062 | /* |
8f4f8c16 HD |
2063 | * Walk the list again, actually closing and freeing it, |
2064 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2065 | */ |
a8fb5618 HD |
2066 | while (vma) |
2067 | vma = remove_vma(vma); | |
e0da382c | 2068 | |
e2cdef8c | 2069 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
2070 | } |
2071 | ||
2072 | /* Insert vm structure into process list sorted by address | |
2073 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
2074 | * then i_mmap_lock is taken here. | |
2075 | */ | |
2076 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
2077 | { | |
2078 | struct vm_area_struct * __vma, * prev; | |
2079 | struct rb_node ** rb_link, * rb_parent; | |
2080 | ||
2081 | /* | |
2082 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2083 | * until its first write fault, when page's anon_vma and index | |
2084 | * are set. But now set the vm_pgoff it will almost certainly | |
2085 | * end up with (unless mremap moves it elsewhere before that | |
2086 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2087 | * | |
2088 | * By setting it to reflect the virtual start address of the | |
2089 | * vma, merges and splits can happen in a seamless way, just | |
2090 | * using the existing file pgoff checks and manipulations. | |
2091 | * Similarly in do_mmap_pgoff and in do_brk. | |
2092 | */ | |
2093 | if (!vma->vm_file) { | |
2094 | BUG_ON(vma->anon_vma); | |
2095 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2096 | } | |
2097 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); | |
2098 | if (__vma && __vma->vm_start < vma->vm_end) | |
2099 | return -ENOMEM; | |
2fd4ef85 | 2100 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2101 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2102 | return -ENOMEM; |
1da177e4 LT |
2103 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2104 | return 0; | |
2105 | } | |
2106 | ||
2107 | /* | |
2108 | * Copy the vma structure to a new location in the same mm, | |
2109 | * prior to moving page table entries, to effect an mremap move. | |
2110 | */ | |
2111 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
2112 | unsigned long addr, unsigned long len, pgoff_t pgoff) | |
2113 | { | |
2114 | struct vm_area_struct *vma = *vmap; | |
2115 | unsigned long vma_start = vma->vm_start; | |
2116 | struct mm_struct *mm = vma->vm_mm; | |
2117 | struct vm_area_struct *new_vma, *prev; | |
2118 | struct rb_node **rb_link, *rb_parent; | |
2119 | struct mempolicy *pol; | |
2120 | ||
2121 | /* | |
2122 | * If anonymous vma has not yet been faulted, update new pgoff | |
2123 | * to match new location, to increase its chance of merging. | |
2124 | */ | |
2125 | if (!vma->vm_file && !vma->anon_vma) | |
2126 | pgoff = addr >> PAGE_SHIFT; | |
2127 | ||
2128 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2129 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, | |
2130 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2131 | if (new_vma) { | |
2132 | /* | |
2133 | * Source vma may have been merged into new_vma | |
2134 | */ | |
2135 | if (vma_start >= new_vma->vm_start && | |
2136 | vma_start < new_vma->vm_end) | |
2137 | *vmap = new_vma; | |
2138 | } else { | |
e94b1766 | 2139 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2140 | if (new_vma) { |
2141 | *new_vma = *vma; | |
846a16bf | 2142 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 LT |
2143 | if (IS_ERR(pol)) { |
2144 | kmem_cache_free(vm_area_cachep, new_vma); | |
2145 | return NULL; | |
2146 | } | |
2147 | vma_set_policy(new_vma, pol); | |
2148 | new_vma->vm_start = addr; | |
2149 | new_vma->vm_end = addr + len; | |
2150 | new_vma->vm_pgoff = pgoff; | |
925d1c40 | 2151 | if (new_vma->vm_file) { |
1da177e4 | 2152 | get_file(new_vma->vm_file); |
925d1c40 MH |
2153 | if (vma->vm_flags & VM_EXECUTABLE) |
2154 | added_exe_file_vma(mm); | |
2155 | } | |
1da177e4 LT |
2156 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
2157 | new_vma->vm_ops->open(new_vma); | |
2158 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
2159 | } | |
2160 | } | |
2161 | return new_vma; | |
2162 | } | |
119f657c | 2163 | |
2164 | /* | |
2165 | * Return true if the calling process may expand its vm space by the passed | |
2166 | * number of pages | |
2167 | */ | |
2168 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2169 | { | |
2170 | unsigned long cur = mm->total_vm; /* pages */ | |
2171 | unsigned long lim; | |
2172 | ||
2173 | lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; | |
2174 | ||
2175 | if (cur + npages > lim) | |
2176 | return 0; | |
2177 | return 1; | |
2178 | } | |
fa5dc22f RM |
2179 | |
2180 | ||
b1d0e4f5 NP |
2181 | static int special_mapping_fault(struct vm_area_struct *vma, |
2182 | struct vm_fault *vmf) | |
fa5dc22f | 2183 | { |
b1d0e4f5 | 2184 | pgoff_t pgoff; |
fa5dc22f RM |
2185 | struct page **pages; |
2186 | ||
b1d0e4f5 NP |
2187 | /* |
2188 | * special mappings have no vm_file, and in that case, the mm | |
2189 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2190 | * We are allowed to do this because we are the mm; do not copy | |
2191 | * this code into drivers! | |
2192 | */ | |
2193 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2194 | |
b1d0e4f5 NP |
2195 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2196 | pgoff--; | |
fa5dc22f RM |
2197 | |
2198 | if (*pages) { | |
2199 | struct page *page = *pages; | |
2200 | get_page(page); | |
b1d0e4f5 NP |
2201 | vmf->page = page; |
2202 | return 0; | |
fa5dc22f RM |
2203 | } |
2204 | ||
b1d0e4f5 | 2205 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2206 | } |
2207 | ||
2208 | /* | |
2209 | * Having a close hook prevents vma merging regardless of flags. | |
2210 | */ | |
2211 | static void special_mapping_close(struct vm_area_struct *vma) | |
2212 | { | |
2213 | } | |
2214 | ||
2215 | static struct vm_operations_struct special_mapping_vmops = { | |
2216 | .close = special_mapping_close, | |
b1d0e4f5 | 2217 | .fault = special_mapping_fault, |
fa5dc22f RM |
2218 | }; |
2219 | ||
2220 | /* | |
2221 | * Called with mm->mmap_sem held for writing. | |
2222 | * Insert a new vma covering the given region, with the given flags. | |
2223 | * Its pages are supplied by the given array of struct page *. | |
2224 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2225 | * The region past the last page supplied will always produce SIGBUS. | |
2226 | * The array pointer and the pages it points to are assumed to stay alive | |
2227 | * for as long as this mapping might exist. | |
2228 | */ | |
2229 | int install_special_mapping(struct mm_struct *mm, | |
2230 | unsigned long addr, unsigned long len, | |
2231 | unsigned long vm_flags, struct page **pages) | |
2232 | { | |
2233 | struct vm_area_struct *vma; | |
2234 | ||
2235 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2236 | if (unlikely(vma == NULL)) | |
2237 | return -ENOMEM; | |
2238 | ||
2239 | vma->vm_mm = mm; | |
2240 | vma->vm_start = addr; | |
2241 | vma->vm_end = addr + len; | |
2242 | ||
2f98735c | 2243 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
3ed75eb8 | 2244 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2245 | |
2246 | vma->vm_ops = &special_mapping_vmops; | |
2247 | vma->vm_private_data = pages; | |
2248 | ||
2249 | if (unlikely(insert_vm_struct(mm, vma))) { | |
2250 | kmem_cache_free(vm_area_cachep, vma); | |
2251 | return -ENOMEM; | |
2252 | } | |
2253 | ||
2254 | mm->total_vm += len >> PAGE_SHIFT; | |
2255 | ||
2256 | return 0; | |
2257 | } |