Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mmap.c | |
3 | * | |
4 | * Written by obz. | |
5 | * | |
046c6884 | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
7 | */ |
8 | ||
9 | #include <linux/slab.h> | |
4af3c9cc | 10 | #include <linux/backing-dev.h> |
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/shm.h> | |
13 | #include <linux/mman.h> | |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/swap.h> | |
16 | #include <linux/syscalls.h> | |
c59ede7b | 17 | #include <linux/capability.h> |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/file.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/security.h> | |
23 | #include <linux/hugetlb.h> | |
24 | #include <linux/profile.h> | |
b95f1b31 | 25 | #include <linux/export.h> |
1da177e4 LT |
26 | #include <linux/mount.h> |
27 | #include <linux/mempolicy.h> | |
28 | #include <linux/rmap.h> | |
cddb8a5c | 29 | #include <linux/mmu_notifier.h> |
cdd6c482 | 30 | #include <linux/perf_event.h> |
120a795d | 31 | #include <linux/audit.h> |
b15d00b6 | 32 | #include <linux/khugepaged.h> |
1da177e4 LT |
33 | |
34 | #include <asm/uaccess.h> | |
35 | #include <asm/cacheflush.h> | |
36 | #include <asm/tlb.h> | |
d6dd61c8 | 37 | #include <asm/mmu_context.h> |
1da177e4 | 38 | |
42b77728 JB |
39 | #include "internal.h" |
40 | ||
3a459756 KK |
41 | #ifndef arch_mmap_check |
42 | #define arch_mmap_check(addr, len, flags) (0) | |
43 | #endif | |
44 | ||
08e7d9b5 MS |
45 | #ifndef arch_rebalance_pgtables |
46 | #define arch_rebalance_pgtables(addr, len) (addr) | |
47 | #endif | |
48 | ||
e0da382c HD |
49 | static void unmap_region(struct mm_struct *mm, |
50 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
51 | unsigned long start, unsigned long end); | |
52 | ||
1da177e4 LT |
53 | /* |
54 | * WARNING: the debugging will use recursive algorithms so never enable this | |
55 | * unless you know what you are doing. | |
56 | */ | |
57 | #undef DEBUG_MM_RB | |
58 | ||
59 | /* description of effects of mapping type and prot in current implementation. | |
60 | * this is due to the limited x86 page protection hardware. The expected | |
61 | * behavior is in parens: | |
62 | * | |
63 | * map_type prot | |
64 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
65 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
66 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
67 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
68 | * | |
69 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
70 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
71 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
72 | * | |
73 | */ | |
74 | pgprot_t protection_map[16] = { | |
75 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
76 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
77 | }; | |
78 | ||
804af2cf HD |
79 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
80 | { | |
b845f313 DK |
81 | return __pgprot(pgprot_val(protection_map[vm_flags & |
82 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
83 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
84 | } |
85 | EXPORT_SYMBOL(vm_get_page_prot); | |
86 | ||
34679d7e SL |
87 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
88 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ | |
c3d8c141 | 89 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
34679d7e SL |
90 | /* |
91 | * Make sure vm_committed_as in one cacheline and not cacheline shared with | |
92 | * other variables. It can be updated by several CPUs frequently. | |
93 | */ | |
94 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; | |
1da177e4 LT |
95 | |
96 | /* | |
97 | * Check that a process has enough memory to allocate a new virtual | |
98 | * mapping. 0 means there is enough memory for the allocation to | |
99 | * succeed and -ENOMEM implies there is not. | |
100 | * | |
101 | * We currently support three overcommit policies, which are set via the | |
102 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
103 | * | |
104 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
105 | * Additional code 2002 Jul 20 by Robert Love. | |
106 | * | |
107 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
108 | * | |
109 | * Note this is a helper function intended to be used by LSMs which | |
110 | * wish to use this logic. | |
111 | */ | |
34b4e4aa | 112 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
113 | { |
114 | unsigned long free, allowed; | |
115 | ||
116 | vm_acct_memory(pages); | |
117 | ||
118 | /* | |
119 | * Sometimes we want to use more memory than we have | |
120 | */ | |
121 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
122 | return 0; | |
123 | ||
124 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
c15bef30 DF |
125 | free = global_page_state(NR_FREE_PAGES); |
126 | free += global_page_state(NR_FILE_PAGES); | |
127 | ||
128 | /* | |
129 | * shmem pages shouldn't be counted as free in this | |
130 | * case, they can't be purged, only swapped out, and | |
131 | * that won't affect the overall amount of available | |
132 | * memory in the system. | |
133 | */ | |
134 | free -= global_page_state(NR_SHMEM); | |
1da177e4 | 135 | |
1da177e4 LT |
136 | free += nr_swap_pages; |
137 | ||
138 | /* | |
139 | * Any slabs which are created with the | |
140 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
141 | * which are reclaimable, under pressure. The dentry | |
142 | * cache and most inode caches should fall into this | |
143 | */ | |
972d1a7b | 144 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 | 145 | |
6d9f7839 HA |
146 | /* |
147 | * Leave reserved pages. The pages are not for anonymous pages. | |
148 | */ | |
c15bef30 | 149 | if (free <= totalreserve_pages) |
6d9f7839 HA |
150 | goto error; |
151 | else | |
c15bef30 | 152 | free -= totalreserve_pages; |
6d9f7839 HA |
153 | |
154 | /* | |
155 | * Leave the last 3% for root | |
156 | */ | |
1da177e4 | 157 | if (!cap_sys_admin) |
c15bef30 | 158 | free -= free / 32; |
1da177e4 LT |
159 | |
160 | if (free > pages) | |
161 | return 0; | |
6d9f7839 HA |
162 | |
163 | goto error; | |
1da177e4 LT |
164 | } |
165 | ||
166 | allowed = (totalram_pages - hugetlb_total_pages()) | |
167 | * sysctl_overcommit_ratio / 100; | |
168 | /* | |
169 | * Leave the last 3% for root | |
170 | */ | |
171 | if (!cap_sys_admin) | |
172 | allowed -= allowed / 32; | |
173 | allowed += total_swap_pages; | |
174 | ||
175 | /* Don't let a single process grow too big: | |
176 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
177 | if (mm) |
178 | allowed -= mm->total_vm / 32; | |
1da177e4 | 179 | |
00a62ce9 | 180 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 181 | return 0; |
6d9f7839 | 182 | error: |
1da177e4 LT |
183 | vm_unacct_memory(pages); |
184 | ||
185 | return -ENOMEM; | |
186 | } | |
187 | ||
1da177e4 | 188 | /* |
3d48ae45 | 189 | * Requires inode->i_mapping->i_mmap_mutex |
1da177e4 LT |
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; | |
3d48ae45 | 217 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 218 | __remove_shared_vm_struct(vma, file, mapping); |
3d48ae45 | 219 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 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 | ||
e4eb1ff6 LT |
243 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
244 | ||
6a6160a7 | 245 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
246 | { |
247 | unsigned long rlim, retval; | |
248 | unsigned long newbrk, oldbrk; | |
249 | struct mm_struct *mm = current->mm; | |
a5b4592c | 250 | unsigned long min_brk; |
1da177e4 LT |
251 | |
252 | down_write(&mm->mmap_sem); | |
253 | ||
a5b4592c | 254 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
255 | /* |
256 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
257 | * randomize_va_space to 2, which will still cause mm->start_brk | |
258 | * to be arbitrarily shifted | |
259 | */ | |
4471a675 | 260 | if (current->brk_randomized) |
5520e894 JK |
261 | min_brk = mm->start_brk; |
262 | else | |
263 | min_brk = mm->end_data; | |
a5b4592c JK |
264 | #else |
265 | min_brk = mm->start_brk; | |
266 | #endif | |
267 | if (brk < min_brk) | |
1da177e4 | 268 | goto out; |
1e624196 RG |
269 | |
270 | /* | |
271 | * Check against rlimit here. If this check is done later after the test | |
272 | * of oldbrk with newbrk then it can escape the test and let the data | |
273 | * segment grow beyond its set limit the in case where the limit is | |
274 | * not page aligned -Ram Gupta | |
275 | */ | |
59e99e5b | 276 | rlim = rlimit(RLIMIT_DATA); |
c1d171a0 JK |
277 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
278 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
279 | goto out; |
280 | ||
1da177e4 LT |
281 | newbrk = PAGE_ALIGN(brk); |
282 | oldbrk = PAGE_ALIGN(mm->brk); | |
283 | if (oldbrk == newbrk) | |
284 | goto set_brk; | |
285 | ||
286 | /* Always allow shrinking brk. */ | |
287 | if (brk <= mm->brk) { | |
288 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
289 | goto set_brk; | |
290 | goto out; | |
291 | } | |
292 | ||
1da177e4 LT |
293 | /* Check against existing mmap mappings. */ |
294 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
295 | goto out; | |
296 | ||
297 | /* Ok, looks good - let it rip. */ | |
298 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
299 | goto out; | |
300 | set_brk: | |
301 | mm->brk = brk; | |
302 | out: | |
303 | retval = mm->brk; | |
304 | up_write(&mm->mmap_sem); | |
305 | return retval; | |
306 | } | |
307 | ||
308 | #ifdef DEBUG_MM_RB | |
309 | static int browse_rb(struct rb_root *root) | |
310 | { | |
311 | int i = 0, j; | |
312 | struct rb_node *nd, *pn = NULL; | |
313 | unsigned long prev = 0, pend = 0; | |
314 | ||
315 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
316 | struct vm_area_struct *vma; | |
317 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
318 | if (vma->vm_start < prev) | |
319 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
320 | if (vma->vm_start < pend) | |
321 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
322 | if (vma->vm_start > vma->vm_end) | |
323 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
324 | i++; | |
325 | pn = nd; | |
d1af65d1 DM |
326 | prev = vma->vm_start; |
327 | pend = vma->vm_end; | |
1da177e4 LT |
328 | } |
329 | j = 0; | |
330 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
331 | j++; | |
332 | } | |
333 | if (i != j) | |
334 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
335 | return i; | |
336 | } | |
337 | ||
338 | void validate_mm(struct mm_struct *mm) | |
339 | { | |
340 | int bug = 0; | |
341 | int i = 0; | |
342 | struct vm_area_struct *tmp = mm->mmap; | |
343 | while (tmp) { | |
344 | tmp = tmp->vm_next; | |
345 | i++; | |
346 | } | |
347 | if (i != mm->map_count) | |
348 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
349 | i = browse_rb(&mm->mm_rb); | |
350 | if (i != mm->map_count) | |
351 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 352 | BUG_ON(bug); |
1da177e4 LT |
353 | } |
354 | #else | |
355 | #define validate_mm(mm) do { } while (0) | |
356 | #endif | |
357 | ||
358 | static struct vm_area_struct * | |
359 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, | |
360 | struct vm_area_struct **pprev, struct rb_node ***rb_link, | |
361 | struct rb_node ** rb_parent) | |
362 | { | |
363 | struct vm_area_struct * vma; | |
364 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; | |
365 | ||
366 | __rb_link = &mm->mm_rb.rb_node; | |
367 | rb_prev = __rb_parent = NULL; | |
368 | vma = NULL; | |
369 | ||
370 | while (*__rb_link) { | |
371 | struct vm_area_struct *vma_tmp; | |
372 | ||
373 | __rb_parent = *__rb_link; | |
374 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
375 | ||
376 | if (vma_tmp->vm_end > addr) { | |
377 | vma = vma_tmp; | |
378 | if (vma_tmp->vm_start <= addr) | |
dfe195fb | 379 | break; |
1da177e4 LT |
380 | __rb_link = &__rb_parent->rb_left; |
381 | } else { | |
382 | rb_prev = __rb_parent; | |
383 | __rb_link = &__rb_parent->rb_right; | |
384 | } | |
385 | } | |
386 | ||
387 | *pprev = NULL; | |
388 | if (rb_prev) | |
389 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
390 | *rb_link = __rb_link; | |
391 | *rb_parent = __rb_parent; | |
392 | return vma; | |
393 | } | |
394 | ||
1da177e4 LT |
395 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
396 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
397 | { | |
398 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
399 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
400 | } | |
401 | ||
cb8f488c | 402 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 403 | { |
48aae425 | 404 | struct file *file; |
1da177e4 LT |
405 | |
406 | file = vma->vm_file; | |
407 | if (file) { | |
408 | struct address_space *mapping = file->f_mapping; | |
409 | ||
410 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 411 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
412 | if (vma->vm_flags & VM_SHARED) |
413 | mapping->i_mmap_writable++; | |
414 | ||
415 | flush_dcache_mmap_lock(mapping); | |
416 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
417 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
418 | else | |
419 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
420 | flush_dcache_mmap_unlock(mapping); | |
421 | } | |
422 | } | |
423 | ||
424 | static void | |
425 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
426 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
427 | struct rb_node *rb_parent) | |
428 | { | |
429 | __vma_link_list(mm, vma, prev, rb_parent); | |
430 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
431 | } |
432 | ||
433 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
434 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
435 | struct rb_node *rb_parent) | |
436 | { | |
437 | struct address_space *mapping = NULL; | |
438 | ||
439 | if (vma->vm_file) | |
440 | mapping = vma->vm_file->f_mapping; | |
441 | ||
97a89413 | 442 | if (mapping) |
3d48ae45 | 443 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 LT |
444 | |
445 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
446 | __vma_link_file(vma); | |
447 | ||
1da177e4 | 448 | if (mapping) |
3d48ae45 | 449 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
450 | |
451 | mm->map_count++; | |
452 | validate_mm(mm); | |
453 | } | |
454 | ||
455 | /* | |
88f6b4c3 KC |
456 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
457 | * mm's list and rbtree. It has already been inserted into the prio_tree. | |
1da177e4 | 458 | */ |
48aae425 | 459 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 460 | { |
48aae425 Z |
461 | struct vm_area_struct *__vma, *prev; |
462 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
463 | |
464 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); | |
46a350ef | 465 | BUG_ON(__vma && __vma->vm_start < vma->vm_end); |
1da177e4 LT |
466 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
467 | mm->map_count++; | |
468 | } | |
469 | ||
470 | static inline void | |
471 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
472 | struct vm_area_struct *prev) | |
473 | { | |
297c5eee LT |
474 | struct vm_area_struct *next = vma->vm_next; |
475 | ||
476 | prev->vm_next = next; | |
477 | if (next) | |
478 | next->vm_prev = prev; | |
1da177e4 LT |
479 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
480 | if (mm->mmap_cache == vma) | |
481 | mm->mmap_cache = prev; | |
482 | } | |
483 | ||
484 | /* | |
485 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
486 | * is already present in an i_mmap tree without adjusting the tree. | |
487 | * The following helper function should be used when such adjustments | |
488 | * are necessary. The "insert" vma (if any) is to be inserted | |
489 | * before we drop the necessary locks. | |
490 | */ | |
5beb4930 | 491 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
492 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
493 | { | |
494 | struct mm_struct *mm = vma->vm_mm; | |
495 | struct vm_area_struct *next = vma->vm_next; | |
496 | struct vm_area_struct *importer = NULL; | |
497 | struct address_space *mapping = NULL; | |
498 | struct prio_tree_root *root = NULL; | |
012f1800 | 499 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 500 | struct file *file = vma->vm_file; |
1da177e4 LT |
501 | long adjust_next = 0; |
502 | int remove_next = 0; | |
503 | ||
504 | if (next && !insert) { | |
287d97ac LT |
505 | struct vm_area_struct *exporter = NULL; |
506 | ||
1da177e4 LT |
507 | if (end >= next->vm_end) { |
508 | /* | |
509 | * vma expands, overlapping all the next, and | |
510 | * perhaps the one after too (mprotect case 6). | |
511 | */ | |
512 | again: remove_next = 1 + (end > next->vm_end); | |
513 | end = next->vm_end; | |
287d97ac | 514 | exporter = next; |
1da177e4 LT |
515 | importer = vma; |
516 | } else if (end > next->vm_start) { | |
517 | /* | |
518 | * vma expands, overlapping part of the next: | |
519 | * mprotect case 5 shifting the boundary up. | |
520 | */ | |
521 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 522 | exporter = next; |
1da177e4 LT |
523 | importer = vma; |
524 | } else if (end < vma->vm_end) { | |
525 | /* | |
526 | * vma shrinks, and !insert tells it's not | |
527 | * split_vma inserting another: so it must be | |
528 | * mprotect case 4 shifting the boundary down. | |
529 | */ | |
530 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
287d97ac | 531 | exporter = vma; |
1da177e4 LT |
532 | importer = next; |
533 | } | |
1da177e4 | 534 | |
5beb4930 RR |
535 | /* |
536 | * Easily overlooked: when mprotect shifts the boundary, | |
537 | * make sure the expanding vma has anon_vma set if the | |
538 | * shrinking vma had, to cover any anon pages imported. | |
539 | */ | |
287d97ac LT |
540 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
541 | if (anon_vma_clone(importer, exporter)) | |
5beb4930 | 542 | return -ENOMEM; |
287d97ac | 543 | importer->anon_vma = exporter->anon_vma; |
5beb4930 RR |
544 | } |
545 | } | |
546 | ||
1da177e4 LT |
547 | if (file) { |
548 | mapping = file->f_mapping; | |
549 | if (!(vma->vm_flags & VM_NONLINEAR)) | |
550 | root = &mapping->i_mmap; | |
3d48ae45 | 551 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 552 | if (insert) { |
1da177e4 LT |
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 | ||
94fcc585 AA |
563 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
564 | ||
012f1800 RR |
565 | /* |
566 | * When changing only vma->vm_end, we don't really need anon_vma | |
567 | * lock. This is a fairly rare case by itself, but the anon_vma | |
568 | * lock may be shared between many sibling processes. Skipping | |
569 | * the lock for brk adjustments makes a difference sometimes. | |
570 | */ | |
5f70b962 | 571 | if (vma->anon_vma && (importer || start != vma->vm_start)) { |
012f1800 RR |
572 | anon_vma = vma->anon_vma; |
573 | anon_vma_lock(anon_vma); | |
574 | } | |
575 | ||
1da177e4 LT |
576 | if (root) { |
577 | flush_dcache_mmap_lock(mapping); | |
578 | vma_prio_tree_remove(vma, root); | |
579 | if (adjust_next) | |
580 | vma_prio_tree_remove(next, root); | |
581 | } | |
582 | ||
583 | vma->vm_start = start; | |
584 | vma->vm_end = end; | |
585 | vma->vm_pgoff = pgoff; | |
586 | if (adjust_next) { | |
587 | next->vm_start += adjust_next << PAGE_SHIFT; | |
588 | next->vm_pgoff += adjust_next; | |
589 | } | |
590 | ||
591 | if (root) { | |
592 | if (adjust_next) | |
593 | vma_prio_tree_insert(next, root); | |
594 | vma_prio_tree_insert(vma, root); | |
595 | flush_dcache_mmap_unlock(mapping); | |
596 | } | |
597 | ||
598 | if (remove_next) { | |
599 | /* | |
600 | * vma_merge has merged next into vma, and needs | |
601 | * us to remove next before dropping the locks. | |
602 | */ | |
603 | __vma_unlink(mm, next, vma); | |
604 | if (file) | |
605 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
606 | } else if (insert) { |
607 | /* | |
608 | * split_vma has split insert from vma, and needs | |
609 | * us to insert it before dropping the locks | |
610 | * (it may either follow vma or precede it). | |
611 | */ | |
612 | __insert_vm_struct(mm, insert); | |
613 | } | |
614 | ||
012f1800 RR |
615 | if (anon_vma) |
616 | anon_vma_unlock(anon_vma); | |
1da177e4 | 617 | if (mapping) |
3d48ae45 | 618 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
619 | |
620 | if (remove_next) { | |
925d1c40 | 621 | if (file) { |
1da177e4 | 622 | fput(file); |
925d1c40 MH |
623 | if (next->vm_flags & VM_EXECUTABLE) |
624 | removed_exe_file_vma(mm); | |
625 | } | |
5beb4930 RR |
626 | if (next->anon_vma) |
627 | anon_vma_merge(vma, next); | |
1da177e4 | 628 | mm->map_count--; |
f0be3d32 | 629 | mpol_put(vma_policy(next)); |
1da177e4 LT |
630 | kmem_cache_free(vm_area_cachep, next); |
631 | /* | |
632 | * In mprotect's case 6 (see comments on vma_merge), | |
633 | * we must remove another next too. It would clutter | |
634 | * up the code too much to do both in one go. | |
635 | */ | |
636 | if (remove_next == 2) { | |
637 | next = vma->vm_next; | |
638 | goto again; | |
639 | } | |
640 | } | |
641 | ||
642 | validate_mm(mm); | |
5beb4930 RR |
643 | |
644 | return 0; | |
1da177e4 LT |
645 | } |
646 | ||
647 | /* | |
648 | * If the vma has a ->close operation then the driver probably needs to release | |
649 | * per-vma resources, so we don't attempt to merge those. | |
650 | */ | |
1da177e4 LT |
651 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
652 | struct file *file, unsigned long vm_flags) | |
653 | { | |
8314c4f2 HD |
654 | /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ |
655 | if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) | |
1da177e4 LT |
656 | return 0; |
657 | if (vma->vm_file != file) | |
658 | return 0; | |
659 | if (vma->vm_ops && vma->vm_ops->close) | |
660 | return 0; | |
661 | return 1; | |
662 | } | |
663 | ||
664 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
665 | struct anon_vma *anon_vma2, |
666 | struct vm_area_struct *vma) | |
1da177e4 | 667 | { |
965f55de SL |
668 | /* |
669 | * The list_is_singular() test is to avoid merging VMA cloned from | |
670 | * parents. This can improve scalability caused by anon_vma lock. | |
671 | */ | |
672 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
673 | list_is_singular(&vma->anon_vma_chain))) | |
674 | return 1; | |
675 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
676 | } |
677 | ||
678 | /* | |
679 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
680 | * in front of (at a lower virtual address and file offset than) the vma. | |
681 | * | |
682 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
683 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
684 | * | |
685 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
686 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
687 | * wrap, nor mmaps which cover the final page at index -1UL. | |
688 | */ | |
689 | static int | |
690 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
691 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
692 | { | |
693 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 694 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
695 | if (vma->vm_pgoff == vm_pgoff) |
696 | return 1; | |
697 | } | |
698 | return 0; | |
699 | } | |
700 | ||
701 | /* | |
702 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
703 | * beyond (at a higher virtual address and file offset than) the vma. | |
704 | * | |
705 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
706 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
707 | */ | |
708 | static int | |
709 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
710 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
711 | { | |
712 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 713 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
714 | pgoff_t vm_pglen; |
715 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
716 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
717 | return 1; | |
718 | } | |
719 | return 0; | |
720 | } | |
721 | ||
722 | /* | |
723 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
724 | * whether that can be merged with its predecessor or its successor. | |
725 | * Or both (it neatly fills a hole). | |
726 | * | |
727 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
728 | * certain not to be mapped by the time vma_merge is called; but when | |
729 | * called for mprotect, it is certain to be already mapped (either at | |
730 | * an offset within prev, or at the start of next), and the flags of | |
731 | * this area are about to be changed to vm_flags - and the no-change | |
732 | * case has already been eliminated. | |
733 | * | |
734 | * The following mprotect cases have to be considered, where AAAA is | |
735 | * the area passed down from mprotect_fixup, never extending beyond one | |
736 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
737 | * | |
738 | * AAAA AAAA AAAA AAAA | |
739 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
740 | * cannot merge might become might become might become | |
741 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
742 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
743 | * mremap move: PPPPNNNNNNNN 8 | |
744 | * AAAA | |
745 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
746 | * might become case 1 below case 2 below case 3 below | |
747 | * | |
748 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
749 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
750 | */ | |
751 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
752 | struct vm_area_struct *prev, unsigned long addr, | |
753 | unsigned long end, unsigned long vm_flags, | |
754 | struct anon_vma *anon_vma, struct file *file, | |
755 | pgoff_t pgoff, struct mempolicy *policy) | |
756 | { | |
757 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
758 | struct vm_area_struct *area, *next; | |
5beb4930 | 759 | int err; |
1da177e4 LT |
760 | |
761 | /* | |
762 | * We later require that vma->vm_flags == vm_flags, | |
763 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
764 | */ | |
765 | if (vm_flags & VM_SPECIAL) | |
766 | return NULL; | |
767 | ||
768 | if (prev) | |
769 | next = prev->vm_next; | |
770 | else | |
771 | next = mm->mmap; | |
772 | area = next; | |
773 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
774 | next = next->vm_next; | |
775 | ||
776 | /* | |
777 | * Can it merge with the predecessor? | |
778 | */ | |
779 | if (prev && prev->vm_end == addr && | |
780 | mpol_equal(vma_policy(prev), policy) && | |
781 | can_vma_merge_after(prev, vm_flags, | |
782 | anon_vma, file, pgoff)) { | |
783 | /* | |
784 | * OK, it can. Can we now merge in the successor as well? | |
785 | */ | |
786 | if (next && end == next->vm_start && | |
787 | mpol_equal(policy, vma_policy(next)) && | |
788 | can_vma_merge_before(next, vm_flags, | |
789 | anon_vma, file, pgoff+pglen) && | |
790 | is_mergeable_anon_vma(prev->anon_vma, | |
965f55de | 791 | next->anon_vma, NULL)) { |
1da177e4 | 792 | /* cases 1, 6 */ |
5beb4930 | 793 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
794 | next->vm_end, prev->vm_pgoff, NULL); |
795 | } else /* cases 2, 5, 7 */ | |
5beb4930 | 796 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 | 797 | end, prev->vm_pgoff, NULL); |
5beb4930 RR |
798 | if (err) |
799 | return NULL; | |
b15d00b6 | 800 | khugepaged_enter_vma_merge(prev); |
1da177e4 LT |
801 | return prev; |
802 | } | |
803 | ||
804 | /* | |
805 | * Can this new request be merged in front of next? | |
806 | */ | |
807 | if (next && end == next->vm_start && | |
808 | mpol_equal(policy, vma_policy(next)) && | |
809 | can_vma_merge_before(next, vm_flags, | |
810 | anon_vma, file, pgoff+pglen)) { | |
811 | if (prev && addr < prev->vm_end) /* case 4 */ | |
5beb4930 | 812 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
813 | addr, prev->vm_pgoff, NULL); |
814 | else /* cases 3, 8 */ | |
5beb4930 | 815 | err = vma_adjust(area, addr, next->vm_end, |
1da177e4 | 816 | next->vm_pgoff - pglen, NULL); |
5beb4930 RR |
817 | if (err) |
818 | return NULL; | |
b15d00b6 | 819 | khugepaged_enter_vma_merge(area); |
1da177e4 LT |
820 | return area; |
821 | } | |
822 | ||
823 | return NULL; | |
824 | } | |
825 | ||
d0e9fe17 LT |
826 | /* |
827 | * Rough compatbility check to quickly see if it's even worth looking | |
828 | * at sharing an anon_vma. | |
829 | * | |
830 | * They need to have the same vm_file, and the flags can only differ | |
831 | * in things that mprotect may change. | |
832 | * | |
833 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
834 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
835 | * there is a vm_ops->close() function, because that indicates that the | |
836 | * driver is doing some kind of reference counting. But that doesn't | |
837 | * really matter for the anon_vma sharing case. | |
838 | */ | |
839 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
840 | { | |
841 | return a->vm_end == b->vm_start && | |
842 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
843 | a->vm_file == b->vm_file && | |
844 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && | |
845 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); | |
846 | } | |
847 | ||
848 | /* | |
849 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
850 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
851 | * the same as 'old', the other will be the new one that is trying | |
852 | * to share the anon_vma. | |
853 | * | |
854 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
855 | * the anon_vma of 'old' is concurrently in the process of being set up | |
856 | * by another page fault trying to merge _that_. But that's ok: if it | |
857 | * is being set up, that automatically means that it will be a singleton | |
858 | * acceptable for merging, so we can do all of this optimistically. But | |
859 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. | |
860 | * | |
861 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
862 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
863 | * is to return an anon_vma that is "complex" due to having gone through | |
864 | * a fork). | |
865 | * | |
866 | * We also make sure that the two vma's are compatible (adjacent, | |
867 | * and with the same memory policies). That's all stable, even with just | |
868 | * a read lock on the mm_sem. | |
869 | */ | |
870 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
871 | { | |
872 | if (anon_vma_compatible(a, b)) { | |
873 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); | |
874 | ||
875 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
876 | return anon_vma; | |
877 | } | |
878 | return NULL; | |
879 | } | |
880 | ||
1da177e4 LT |
881 | /* |
882 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
883 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
884 | * to allocate a new anon_vma. It checks because a repetitive | |
885 | * sequence of mprotects and faults may otherwise lead to distinct | |
886 | * anon_vmas being allocated, preventing vma merge in subsequent | |
887 | * mprotect. | |
888 | */ | |
889 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
890 | { | |
d0e9fe17 | 891 | struct anon_vma *anon_vma; |
1da177e4 | 892 | struct vm_area_struct *near; |
1da177e4 LT |
893 | |
894 | near = vma->vm_next; | |
895 | if (!near) | |
896 | goto try_prev; | |
897 | ||
d0e9fe17 LT |
898 | anon_vma = reusable_anon_vma(near, vma, near); |
899 | if (anon_vma) | |
900 | return anon_vma; | |
1da177e4 | 901 | try_prev: |
9be34c9d | 902 | near = vma->vm_prev; |
1da177e4 LT |
903 | if (!near) |
904 | goto none; | |
905 | ||
d0e9fe17 LT |
906 | anon_vma = reusable_anon_vma(near, near, vma); |
907 | if (anon_vma) | |
908 | return anon_vma; | |
1da177e4 LT |
909 | none: |
910 | /* | |
911 | * There's no absolute need to look only at touching neighbours: | |
912 | * we could search further afield for "compatible" anon_vmas. | |
913 | * But it would probably just be a waste of time searching, | |
914 | * or lead to too many vmas hanging off the same anon_vma. | |
915 | * We're trying to allow mprotect remerging later on, | |
916 | * not trying to minimize memory used for anon_vmas. | |
917 | */ | |
918 | return NULL; | |
919 | } | |
920 | ||
921 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 922 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
923 | struct file *file, long pages) |
924 | { | |
925 | const unsigned long stack_flags | |
926 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
927 | ||
1da177e4 LT |
928 | if (file) { |
929 | mm->shared_vm += pages; | |
930 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
931 | mm->exec_vm += pages; | |
932 | } else if (flags & stack_flags) | |
933 | mm->stack_vm += pages; | |
934 | if (flags & (VM_RESERVED|VM_IO)) | |
935 | mm->reserved_vm += pages; | |
936 | } | |
937 | #endif /* CONFIG_PROC_FS */ | |
938 | ||
40401530 AV |
939 | /* |
940 | * If a hint addr is less than mmap_min_addr change hint to be as | |
941 | * low as possible but still greater than mmap_min_addr | |
942 | */ | |
943 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
944 | { | |
945 | hint &= PAGE_MASK; | |
946 | if (((void *)hint != NULL) && | |
947 | (hint < mmap_min_addr)) | |
948 | return PAGE_ALIGN(mmap_min_addr); | |
949 | return hint; | |
950 | } | |
951 | ||
1da177e4 | 952 | /* |
27f5de79 | 953 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
954 | */ |
955 | ||
6be5ceb0 | 956 | static unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 LT |
957 | unsigned long len, unsigned long prot, |
958 | unsigned long flags, unsigned long pgoff) | |
959 | { | |
960 | struct mm_struct * mm = current->mm; | |
1da177e4 | 961 | struct inode *inode; |
ca16d140 | 962 | vm_flags_t vm_flags; |
1da177e4 | 963 | int error; |
0165ab44 | 964 | unsigned long reqprot = prot; |
1da177e4 | 965 | |
1da177e4 LT |
966 | /* |
967 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
968 | * | |
969 | * (the exception is when the underlying filesystem is noexec | |
970 | * mounted, in which case we dont add PROT_EXEC.) | |
971 | */ | |
972 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 973 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
974 | prot |= PROT_EXEC; |
975 | ||
976 | if (!len) | |
977 | return -EINVAL; | |
978 | ||
7cd94146 EP |
979 | if (!(flags & MAP_FIXED)) |
980 | addr = round_hint_to_min(addr); | |
981 | ||
1da177e4 LT |
982 | /* Careful about overflows.. */ |
983 | len = PAGE_ALIGN(len); | |
9206de95 | 984 | if (!len) |
1da177e4 LT |
985 | return -ENOMEM; |
986 | ||
987 | /* offset overflow? */ | |
988 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
989 | return -EOVERFLOW; | |
990 | ||
991 | /* Too many mappings? */ | |
992 | if (mm->map_count > sysctl_max_map_count) | |
993 | return -ENOMEM; | |
994 | ||
995 | /* Obtain the address to map to. we verify (or select) it and ensure | |
996 | * that it represents a valid section of the address space. | |
997 | */ | |
998 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
999 | if (addr & ~PAGE_MASK) | |
1000 | return addr; | |
1001 | ||
1002 | /* Do simple checking here so the lower-level routines won't have | |
1003 | * to. we assume access permissions have been handled by the open | |
1004 | * of the memory object, so we don't do any here. | |
1005 | */ | |
1006 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
1007 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
1008 | ||
cdf7b341 | 1009 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1010 | if (!can_do_mlock()) |
1011 | return -EPERM; | |
ba470de4 | 1012 | |
1da177e4 LT |
1013 | /* mlock MCL_FUTURE? */ |
1014 | if (vm_flags & VM_LOCKED) { | |
1015 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
1016 | locked = len >> PAGE_SHIFT; |
1017 | locked += mm->locked_vm; | |
59e99e5b | 1018 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 1019 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
1020 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1021 | return -EAGAIN; | |
1022 | } | |
1023 | ||
d3ac7f89 | 1024 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
1025 | |
1026 | if (file) { | |
1027 | switch (flags & MAP_TYPE) { | |
1028 | case MAP_SHARED: | |
1029 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1030 | return -EACCES; | |
1031 | ||
1032 | /* | |
1033 | * Make sure we don't allow writing to an append-only | |
1034 | * file.. | |
1035 | */ | |
1036 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1037 | return -EACCES; | |
1038 | ||
1039 | /* | |
1040 | * Make sure there are no mandatory locks on the file. | |
1041 | */ | |
1042 | if (locks_verify_locked(inode)) | |
1043 | return -EAGAIN; | |
1044 | ||
1045 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1046 | if (!(file->f_mode & FMODE_WRITE)) | |
1047 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1048 | ||
1049 | /* fall through */ | |
1050 | case MAP_PRIVATE: | |
1051 | if (!(file->f_mode & FMODE_READ)) | |
1052 | return -EACCES; | |
d3ac7f89 | 1053 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1054 | if (vm_flags & VM_EXEC) |
1055 | return -EPERM; | |
1056 | vm_flags &= ~VM_MAYEXEC; | |
1057 | } | |
80c5606c LT |
1058 | |
1059 | if (!file->f_op || !file->f_op->mmap) | |
1060 | return -ENODEV; | |
1da177e4 LT |
1061 | break; |
1062 | ||
1063 | default: | |
1064 | return -EINVAL; | |
1065 | } | |
1066 | } else { | |
1067 | switch (flags & MAP_TYPE) { | |
1068 | case MAP_SHARED: | |
ce363942 TH |
1069 | /* |
1070 | * Ignore pgoff. | |
1071 | */ | |
1072 | pgoff = 0; | |
1da177e4 LT |
1073 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1074 | break; | |
1075 | case MAP_PRIVATE: | |
1076 | /* | |
1077 | * Set pgoff according to addr for anon_vma. | |
1078 | */ | |
1079 | pgoff = addr >> PAGE_SHIFT; | |
1080 | break; | |
1081 | default: | |
1082 | return -EINVAL; | |
1083 | } | |
1084 | } | |
1085 | ||
ed032189 | 1086 | error = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1da177e4 LT |
1087 | if (error) |
1088 | return error; | |
ed032189 | 1089 | |
5a6fe125 | 1090 | return mmap_region(file, addr, len, flags, vm_flags, pgoff); |
0165ab44 | 1091 | } |
6be5ceb0 LT |
1092 | |
1093 | unsigned long do_mmap(struct file *file, unsigned long addr, | |
1094 | unsigned long len, unsigned long prot, | |
1095 | unsigned long flag, unsigned long offset) | |
1096 | { | |
1097 | if (unlikely(offset + PAGE_ALIGN(len) < offset)) | |
1098 | return -EINVAL; | |
1099 | if (unlikely(offset & ~PAGE_MASK)) | |
1100 | return -EINVAL; | |
1101 | return do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); | |
1102 | } | |
1103 | EXPORT_SYMBOL(do_mmap); | |
1104 | ||
1105 | unsigned long vm_mmap(struct file *file, unsigned long addr, | |
1106 | unsigned long len, unsigned long prot, | |
1107 | unsigned long flag, unsigned long offset) | |
1108 | { | |
1109 | unsigned long ret; | |
1110 | struct mm_struct *mm = current->mm; | |
1111 | ||
1112 | down_write(&mm->mmap_sem); | |
1113 | ret = do_mmap(file, addr, len, prot, flag, offset); | |
1114 | up_write(&mm->mmap_sem); | |
1115 | return ret; | |
1116 | } | |
1117 | EXPORT_SYMBOL(vm_mmap); | |
0165ab44 | 1118 | |
66f0dc48 HD |
1119 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1120 | unsigned long, prot, unsigned long, flags, | |
1121 | unsigned long, fd, unsigned long, pgoff) | |
1122 | { | |
1123 | struct file *file = NULL; | |
1124 | unsigned long retval = -EBADF; | |
1125 | ||
1126 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1127 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1128 | if (unlikely(flags & MAP_HUGETLB)) |
1129 | return -EINVAL; | |
1130 | file = fget(fd); | |
1131 | if (!file) | |
1132 | goto out; | |
1133 | } else if (flags & MAP_HUGETLB) { | |
1134 | struct user_struct *user = NULL; | |
1135 | /* | |
1136 | * VM_NORESERVE is used because the reservations will be | |
1137 | * taken when vm_ops->mmap() is called | |
1138 | * A dummy user value is used because we are not locking | |
1139 | * memory so no accounting is necessary | |
1140 | */ | |
40716e29 ST |
1141 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len, |
1142 | VM_NORESERVE, &user, | |
1143 | HUGETLB_ANONHUGE_INODE); | |
66f0dc48 HD |
1144 | if (IS_ERR(file)) |
1145 | return PTR_ERR(file); | |
1146 | } | |
1147 | ||
1148 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1149 | ||
1150 | down_write(¤t->mm->mmap_sem); | |
1151 | retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); | |
1152 | up_write(¤t->mm->mmap_sem); | |
1153 | ||
1154 | if (file) | |
1155 | fput(file); | |
1156 | out: | |
1157 | return retval; | |
1158 | } | |
1159 | ||
a4679373 CH |
1160 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1161 | struct mmap_arg_struct { | |
1162 | unsigned long addr; | |
1163 | unsigned long len; | |
1164 | unsigned long prot; | |
1165 | unsigned long flags; | |
1166 | unsigned long fd; | |
1167 | unsigned long offset; | |
1168 | }; | |
1169 | ||
1170 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1171 | { | |
1172 | struct mmap_arg_struct a; | |
1173 | ||
1174 | if (copy_from_user(&a, arg, sizeof(a))) | |
1175 | return -EFAULT; | |
1176 | if (a.offset & ~PAGE_MASK) | |
1177 | return -EINVAL; | |
1178 | ||
1179 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1180 | a.offset >> PAGE_SHIFT); | |
1181 | } | |
1182 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1183 | ||
4e950f6f AD |
1184 | /* |
1185 | * Some shared mappigns will want the pages marked read-only | |
1186 | * to track write events. If so, we'll downgrade vm_page_prot | |
1187 | * to the private version (using protection_map[] without the | |
1188 | * VM_SHARED bit). | |
1189 | */ | |
1190 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1191 | { | |
ca16d140 | 1192 | vm_flags_t vm_flags = vma->vm_flags; |
4e950f6f AD |
1193 | |
1194 | /* If it was private or non-writable, the write bit is already clear */ | |
1195 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1196 | return 0; | |
1197 | ||
1198 | /* The backer wishes to know when pages are first written to? */ | |
1199 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1200 | return 1; | |
1201 | ||
1202 | /* The open routine did something to the protections already? */ | |
1203 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1204 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1205 | return 0; |
1206 | ||
1207 | /* Specialty mapping? */ | |
1208 | if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) | |
1209 | return 0; | |
1210 | ||
1211 | /* Can the mapping track the dirty pages? */ | |
1212 | return vma->vm_file && vma->vm_file->f_mapping && | |
1213 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1214 | } | |
1215 | ||
fc8744ad LT |
1216 | /* |
1217 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1218 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1219 | */ |
ca16d140 | 1220 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1221 | { |
5a6fe125 MG |
1222 | /* |
1223 | * hugetlb has its own accounting separate from the core VM | |
1224 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1225 | */ | |
1226 | if (file && is_file_hugepages(file)) | |
1227 | return 0; | |
1228 | ||
fc8744ad LT |
1229 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1230 | } | |
1231 | ||
0165ab44 MS |
1232 | unsigned long mmap_region(struct file *file, unsigned long addr, |
1233 | unsigned long len, unsigned long flags, | |
ca16d140 | 1234 | vm_flags_t vm_flags, unsigned long pgoff) |
0165ab44 MS |
1235 | { |
1236 | struct mm_struct *mm = current->mm; | |
1237 | struct vm_area_struct *vma, *prev; | |
1238 | int correct_wcount = 0; | |
1239 | int error; | |
1240 | struct rb_node **rb_link, *rb_parent; | |
1241 | unsigned long charged = 0; | |
1242 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; | |
1243 | ||
1da177e4 LT |
1244 | /* Clear old maps */ |
1245 | error = -ENOMEM; | |
1246 | munmap_back: | |
1247 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
1248 | if (vma && vma->vm_start < addr + len) { | |
1249 | if (do_munmap(mm, addr, len)) | |
1250 | return -ENOMEM; | |
1251 | goto munmap_back; | |
1252 | } | |
1253 | ||
1254 | /* Check against address space limit. */ | |
119f657c | 1255 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1256 | return -ENOMEM; |
1257 | ||
fc8744ad LT |
1258 | /* |
1259 | * Set 'VM_NORESERVE' if we should not account for the | |
5a6fe125 | 1260 | * memory use of this mapping. |
fc8744ad | 1261 | */ |
5a6fe125 MG |
1262 | if ((flags & MAP_NORESERVE)) { |
1263 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1264 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1265 | vm_flags |= VM_NORESERVE; | |
1266 | ||
1267 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1268 | if (file && is_file_hugepages(file)) | |
1269 | vm_flags |= VM_NORESERVE; | |
1270 | } | |
cdfd4325 | 1271 | |
fc8744ad LT |
1272 | /* |
1273 | * Private writable mapping: check memory availability | |
1274 | */ | |
5a6fe125 | 1275 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1276 | charged = len >> PAGE_SHIFT; |
191c5424 | 1277 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1278 | return -ENOMEM; |
1279 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1280 | } |
1281 | ||
1282 | /* | |
de33c8db | 1283 | * Can we just expand an old mapping? |
1da177e4 | 1284 | */ |
de33c8db LT |
1285 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1286 | if (vma) | |
1287 | goto out; | |
1da177e4 LT |
1288 | |
1289 | /* | |
1290 | * Determine the object being mapped and call the appropriate | |
1291 | * specific mapper. the address has already been validated, but | |
1292 | * not unmapped, but the maps are removed from the list. | |
1293 | */ | |
c5e3b83e | 1294 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1295 | if (!vma) { |
1296 | error = -ENOMEM; | |
1297 | goto unacct_error; | |
1298 | } | |
1da177e4 LT |
1299 | |
1300 | vma->vm_mm = mm; | |
1301 | vma->vm_start = addr; | |
1302 | vma->vm_end = addr + len; | |
1303 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1304 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1305 | vma->vm_pgoff = pgoff; |
5beb4930 | 1306 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 | 1307 | |
ce8fea7a HD |
1308 | error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */ |
1309 | ||
1da177e4 | 1310 | if (file) { |
1da177e4 LT |
1311 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1312 | goto free_vma; | |
1313 | if (vm_flags & VM_DENYWRITE) { | |
1314 | error = deny_write_access(file); | |
1315 | if (error) | |
1316 | goto free_vma; | |
1317 | correct_wcount = 1; | |
1318 | } | |
1319 | vma->vm_file = file; | |
1320 | get_file(file); | |
1321 | error = file->f_op->mmap(file, vma); | |
1322 | if (error) | |
1323 | goto unmap_and_free_vma; | |
925d1c40 MH |
1324 | if (vm_flags & VM_EXECUTABLE) |
1325 | added_exe_file_vma(mm); | |
f8dbf0a7 HS |
1326 | |
1327 | /* Can addr have changed?? | |
1328 | * | |
1329 | * Answer: Yes, several device drivers can do it in their | |
1330 | * f_op->mmap method. -DaveM | |
1331 | */ | |
1332 | addr = vma->vm_start; | |
1333 | pgoff = vma->vm_pgoff; | |
1334 | vm_flags = vma->vm_flags; | |
1da177e4 | 1335 | } else if (vm_flags & VM_SHARED) { |
835ee797 AV |
1336 | if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))) |
1337 | goto free_vma; | |
1da177e4 LT |
1338 | error = shmem_zero_setup(vma); |
1339 | if (error) | |
1340 | goto free_vma; | |
1341 | } | |
1342 | ||
c9d0bf24 MD |
1343 | if (vma_wants_writenotify(vma)) { |
1344 | pgprot_t pprot = vma->vm_page_prot; | |
1345 | ||
1346 | /* Can vma->vm_page_prot have changed?? | |
1347 | * | |
1348 | * Answer: Yes, drivers may have changed it in their | |
1349 | * f_op->mmap method. | |
1350 | * | |
1351 | * Ensures that vmas marked as uncached stay that way. | |
1352 | */ | |
1ddd439e | 1353 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
c9d0bf24 MD |
1354 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
1355 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
1356 | } | |
d08b3851 | 1357 | |
de33c8db LT |
1358 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1359 | file = vma->vm_file; | |
4d3d5b41 ON |
1360 | |
1361 | /* Once vma denies write, undo our temporary denial count */ | |
1362 | if (correct_wcount) | |
1363 | atomic_inc(&inode->i_writecount); | |
1364 | out: | |
cdd6c482 | 1365 | perf_event_mmap(vma); |
0a4a9391 | 1366 | |
1da177e4 | 1367 | mm->total_vm += len >> PAGE_SHIFT; |
ab50b8ed | 1368 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1369 | if (vm_flags & VM_LOCKED) { |
06f9d8c2 KM |
1370 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
1371 | mm->locked_vm += (len >> PAGE_SHIFT); | |
ba470de4 | 1372 | } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
54cb8821 | 1373 | make_pages_present(addr, addr + len); |
1da177e4 LT |
1374 | return addr; |
1375 | ||
1376 | unmap_and_free_vma: | |
1377 | if (correct_wcount) | |
1378 | atomic_inc(&inode->i_writecount); | |
1379 | vma->vm_file = NULL; | |
1380 | fput(file); | |
1381 | ||
1382 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1383 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1384 | charged = 0; | |
1da177e4 LT |
1385 | free_vma: |
1386 | kmem_cache_free(vm_area_cachep, vma); | |
1387 | unacct_error: | |
1388 | if (charged) | |
1389 | vm_unacct_memory(charged); | |
1390 | return error; | |
1391 | } | |
1392 | ||
1da177e4 LT |
1393 | /* Get an address range which is currently unmapped. |
1394 | * For shmat() with addr=0. | |
1395 | * | |
1396 | * Ugly calling convention alert: | |
1397 | * Return value with the low bits set means error value, | |
1398 | * ie | |
1399 | * if (ret & ~PAGE_MASK) | |
1400 | * error = ret; | |
1401 | * | |
1402 | * This function "knows" that -ENOMEM has the bits set. | |
1403 | */ | |
1404 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1405 | unsigned long | |
1406 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1407 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1408 | { | |
1409 | struct mm_struct *mm = current->mm; | |
1410 | struct vm_area_struct *vma; | |
1411 | unsigned long start_addr; | |
1412 | ||
1413 | if (len > TASK_SIZE) | |
1414 | return -ENOMEM; | |
1415 | ||
06abdfb4 BH |
1416 | if (flags & MAP_FIXED) |
1417 | return addr; | |
1418 | ||
1da177e4 LT |
1419 | if (addr) { |
1420 | addr = PAGE_ALIGN(addr); | |
1421 | vma = find_vma(mm, addr); | |
1422 | if (TASK_SIZE - len >= addr && | |
1423 | (!vma || addr + len <= vma->vm_start)) | |
1424 | return addr; | |
1425 | } | |
1363c3cd WW |
1426 | if (len > mm->cached_hole_size) { |
1427 | start_addr = addr = mm->free_area_cache; | |
1428 | } else { | |
1429 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1430 | mm->cached_hole_size = 0; | |
1431 | } | |
1da177e4 LT |
1432 | |
1433 | full_search: | |
1434 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1435 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1436 | if (TASK_SIZE - len < addr) { | |
1437 | /* | |
1438 | * Start a new search - just in case we missed | |
1439 | * some holes. | |
1440 | */ | |
1441 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1442 | addr = TASK_UNMAPPED_BASE; |
1443 | start_addr = addr; | |
1444 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1445 | goto full_search; |
1446 | } | |
1447 | return -ENOMEM; | |
1448 | } | |
1449 | if (!vma || addr + len <= vma->vm_start) { | |
1450 | /* | |
1451 | * Remember the place where we stopped the search: | |
1452 | */ | |
1453 | mm->free_area_cache = addr + len; | |
1454 | return addr; | |
1455 | } | |
1363c3cd WW |
1456 | if (addr + mm->cached_hole_size < vma->vm_start) |
1457 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1458 | addr = vma->vm_end; |
1459 | } | |
1460 | } | |
1461 | #endif | |
1462 | ||
1363c3cd | 1463 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1464 | { |
1465 | /* | |
1466 | * Is this a new hole at the lowest possible address? | |
1467 | */ | |
f44d2198 | 1468 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) |
1363c3cd | 1469 | mm->free_area_cache = addr; |
1da177e4 LT |
1470 | } |
1471 | ||
1472 | /* | |
1473 | * This mmap-allocator allocates new areas top-down from below the | |
1474 | * stack's low limit (the base): | |
1475 | */ | |
1476 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1477 | unsigned long | |
1478 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1479 | const unsigned long len, const unsigned long pgoff, | |
1480 | const unsigned long flags) | |
1481 | { | |
1482 | struct vm_area_struct *vma; | |
1483 | struct mm_struct *mm = current->mm; | |
b716ad95 | 1484 | unsigned long addr = addr0, start_addr; |
1da177e4 LT |
1485 | |
1486 | /* requested length too big for entire address space */ | |
1487 | if (len > TASK_SIZE) | |
1488 | return -ENOMEM; | |
1489 | ||
06abdfb4 BH |
1490 | if (flags & MAP_FIXED) |
1491 | return addr; | |
1492 | ||
1da177e4 LT |
1493 | /* requesting a specific address */ |
1494 | if (addr) { | |
1495 | addr = PAGE_ALIGN(addr); | |
1496 | vma = find_vma(mm, addr); | |
1497 | if (TASK_SIZE - len >= addr && | |
1498 | (!vma || addr + len <= vma->vm_start)) | |
1499 | return addr; | |
1500 | } | |
1501 | ||
1363c3cd WW |
1502 | /* check if free_area_cache is useful for us */ |
1503 | if (len <= mm->cached_hole_size) { | |
1504 | mm->cached_hole_size = 0; | |
1505 | mm->free_area_cache = mm->mmap_base; | |
1506 | } | |
1507 | ||
b716ad95 | 1508 | try_again: |
1da177e4 | 1509 | /* either no address requested or can't fit in requested address hole */ |
b716ad95 | 1510 | start_addr = addr = mm->free_area_cache; |
73219d17 | 1511 | |
b716ad95 XG |
1512 | if (addr < len) |
1513 | goto fail; | |
1da177e4 | 1514 | |
b716ad95 | 1515 | addr -= len; |
1da177e4 LT |
1516 | do { |
1517 | /* | |
1518 | * Lookup failure means no vma is above this address, | |
1519 | * else if new region fits below vma->vm_start, | |
1520 | * return with success: | |
1521 | */ | |
1522 | vma = find_vma(mm, addr); | |
1523 | if (!vma || addr+len <= vma->vm_start) | |
1524 | /* remember the address as a hint for next time */ | |
1525 | return (mm->free_area_cache = addr); | |
1526 | ||
1363c3cd WW |
1527 | /* remember the largest hole we saw so far */ |
1528 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1529 | mm->cached_hole_size = vma->vm_start - addr; | |
1530 | ||
1da177e4 LT |
1531 | /* try just below the current vma->vm_start */ |
1532 | addr = vma->vm_start-len; | |
49a43876 | 1533 | } while (len < vma->vm_start); |
1da177e4 | 1534 | |
b716ad95 XG |
1535 | fail: |
1536 | /* | |
1537 | * if hint left us with no space for the requested | |
1538 | * mapping then try again: | |
1539 | * | |
1540 | * Note: this is different with the case of bottomup | |
1541 | * which does the fully line-search, but we use find_vma | |
1542 | * here that causes some holes skipped. | |
1543 | */ | |
1544 | if (start_addr != mm->mmap_base) { | |
1545 | mm->free_area_cache = mm->mmap_base; | |
1546 | mm->cached_hole_size = 0; | |
1547 | goto try_again; | |
1548 | } | |
1549 | ||
1da177e4 LT |
1550 | /* |
1551 | * A failed mmap() very likely causes application failure, | |
1552 | * so fall back to the bottom-up function here. This scenario | |
1553 | * can happen with large stack limits and large mmap() | |
1554 | * allocations. | |
1555 | */ | |
1363c3cd WW |
1556 | mm->cached_hole_size = ~0UL; |
1557 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1558 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1559 | /* | |
1560 | * Restore the topdown base: | |
1561 | */ | |
1562 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1563 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1564 | |
1565 | return addr; | |
1566 | } | |
1567 | #endif | |
1568 | ||
1363c3cd | 1569 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1570 | { |
1571 | /* | |
1572 | * Is this a new hole at the highest possible address? | |
1573 | */ | |
1363c3cd WW |
1574 | if (addr > mm->free_area_cache) |
1575 | mm->free_area_cache = addr; | |
1da177e4 LT |
1576 | |
1577 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1578 | if (mm->free_area_cache > mm->mmap_base) |
1579 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1580 | } |
1581 | ||
1582 | unsigned long | |
1583 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1584 | unsigned long pgoff, unsigned long flags) | |
1585 | { | |
06abdfb4 BH |
1586 | unsigned long (*get_area)(struct file *, unsigned long, |
1587 | unsigned long, unsigned long, unsigned long); | |
1588 | ||
9206de95 AV |
1589 | unsigned long error = arch_mmap_check(addr, len, flags); |
1590 | if (error) | |
1591 | return error; | |
1592 | ||
1593 | /* Careful about overflows.. */ | |
1594 | if (len > TASK_SIZE) | |
1595 | return -ENOMEM; | |
1596 | ||
06abdfb4 BH |
1597 | get_area = current->mm->get_unmapped_area; |
1598 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1599 | get_area = file->f_op->get_unmapped_area; | |
1600 | addr = get_area(file, addr, len, pgoff, flags); | |
1601 | if (IS_ERR_VALUE(addr)) | |
1602 | return addr; | |
1da177e4 | 1603 | |
07ab67c8 LT |
1604 | if (addr > TASK_SIZE - len) |
1605 | return -ENOMEM; | |
1606 | if (addr & ~PAGE_MASK) | |
1607 | return -EINVAL; | |
06abdfb4 | 1608 | |
08e7d9b5 | 1609 | return arch_rebalance_pgtables(addr, len); |
1da177e4 LT |
1610 | } |
1611 | ||
1612 | EXPORT_SYMBOL(get_unmapped_area); | |
1613 | ||
1614 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1615 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1616 | { |
1617 | struct vm_area_struct *vma = NULL; | |
1618 | ||
1619 | if (mm) { | |
1620 | /* Check the cache first. */ | |
1621 | /* (Cache hit rate is typically around 35%.) */ | |
1622 | vma = mm->mmap_cache; | |
1623 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1624 | struct rb_node * rb_node; | |
1625 | ||
1626 | rb_node = mm->mm_rb.rb_node; | |
1627 | vma = NULL; | |
1628 | ||
1629 | while (rb_node) { | |
1630 | struct vm_area_struct * vma_tmp; | |
1631 | ||
1632 | vma_tmp = rb_entry(rb_node, | |
1633 | struct vm_area_struct, vm_rb); | |
1634 | ||
1635 | if (vma_tmp->vm_end > addr) { | |
1636 | vma = vma_tmp; | |
1637 | if (vma_tmp->vm_start <= addr) | |
1638 | break; | |
1639 | rb_node = rb_node->rb_left; | |
1640 | } else | |
1641 | rb_node = rb_node->rb_right; | |
1642 | } | |
1643 | if (vma) | |
1644 | mm->mmap_cache = vma; | |
1645 | } | |
1646 | } | |
1647 | return vma; | |
1648 | } | |
1649 | ||
1650 | EXPORT_SYMBOL(find_vma); | |
1651 | ||
6bd4837d KM |
1652 | /* |
1653 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 1654 | */ |
1da177e4 LT |
1655 | struct vm_area_struct * |
1656 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1657 | struct vm_area_struct **pprev) | |
1658 | { | |
6bd4837d | 1659 | struct vm_area_struct *vma; |
1da177e4 | 1660 | |
6bd4837d | 1661 | vma = find_vma(mm, addr); |
83cd904d MP |
1662 | if (vma) { |
1663 | *pprev = vma->vm_prev; | |
1664 | } else { | |
1665 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
1666 | *pprev = NULL; | |
1667 | while (rb_node) { | |
1668 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1669 | rb_node = rb_node->rb_right; | |
1670 | } | |
1671 | } | |
6bd4837d | 1672 | return vma; |
1da177e4 LT |
1673 | } |
1674 | ||
1675 | /* | |
1676 | * Verify that the stack growth is acceptable and | |
1677 | * update accounting. This is shared with both the | |
1678 | * grow-up and grow-down cases. | |
1679 | */ | |
48aae425 | 1680 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
1681 | { |
1682 | struct mm_struct *mm = vma->vm_mm; | |
1683 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1684 | unsigned long new_start; |
1da177e4 LT |
1685 | |
1686 | /* address space limit tests */ | |
119f657c | 1687 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1688 | return -ENOMEM; |
1689 | ||
1690 | /* Stack limit test */ | |
59e99e5b | 1691 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
1da177e4 LT |
1692 | return -ENOMEM; |
1693 | ||
1694 | /* mlock limit tests */ | |
1695 | if (vma->vm_flags & VM_LOCKED) { | |
1696 | unsigned long locked; | |
1697 | unsigned long limit; | |
1698 | locked = mm->locked_vm + grow; | |
59e99e5b JS |
1699 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
1700 | limit >>= PAGE_SHIFT; | |
1da177e4 LT |
1701 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
1702 | return -ENOMEM; | |
1703 | } | |
1704 | ||
0d59a01b AL |
1705 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1706 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1707 | vma->vm_end - size; | |
1708 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1709 | return -EFAULT; | |
1710 | ||
1da177e4 LT |
1711 | /* |
1712 | * Overcommit.. This must be the final test, as it will | |
1713 | * update security statistics. | |
1714 | */ | |
05fa199d | 1715 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
1716 | return -ENOMEM; |
1717 | ||
1718 | /* Ok, everything looks good - let it rip */ | |
1719 | mm->total_vm += grow; | |
1720 | if (vma->vm_flags & VM_LOCKED) | |
1721 | mm->locked_vm += grow; | |
ab50b8ed | 1722 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1723 | return 0; |
1724 | } | |
1725 | ||
46dea3d0 | 1726 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1727 | /* |
46dea3d0 HD |
1728 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1729 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1730 | */ |
46dea3d0 | 1731 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 LT |
1732 | { |
1733 | int error; | |
1734 | ||
1735 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1736 | return -EFAULT; | |
1737 | ||
1738 | /* | |
1739 | * We must make sure the anon_vma is allocated | |
1740 | * so that the anon_vma locking is not a noop. | |
1741 | */ | |
1742 | if (unlikely(anon_vma_prepare(vma))) | |
1743 | return -ENOMEM; | |
bb4a340e | 1744 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1745 | |
1746 | /* | |
1747 | * vma->vm_start/vm_end cannot change under us because the caller | |
1748 | * is required to hold the mmap_sem in read mode. We need the | |
1749 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 1750 | * Also guard against wrapping around to address 0. |
1da177e4 | 1751 | */ |
06b32f3a HD |
1752 | if (address < PAGE_ALIGN(address+4)) |
1753 | address = PAGE_ALIGN(address+4); | |
1754 | else { | |
bb4a340e | 1755 | vma_unlock_anon_vma(vma); |
06b32f3a HD |
1756 | return -ENOMEM; |
1757 | } | |
1da177e4 LT |
1758 | error = 0; |
1759 | ||
1760 | /* Somebody else might have raced and expanded it already */ | |
1761 | if (address > vma->vm_end) { | |
1762 | unsigned long size, grow; | |
1763 | ||
1764 | size = address - vma->vm_start; | |
1765 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1766 | ||
42c36f63 HD |
1767 | error = -ENOMEM; |
1768 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
1769 | error = acct_stack_growth(vma, size, grow); | |
1770 | if (!error) { | |
1771 | vma->vm_end = address; | |
1772 | perf_event_mmap(vma); | |
1773 | } | |
3af9e859 | 1774 | } |
1da177e4 | 1775 | } |
bb4a340e | 1776 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1777 | khugepaged_enter_vma_merge(vma); |
1da177e4 LT |
1778 | return error; |
1779 | } | |
46dea3d0 HD |
1780 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1781 | ||
1da177e4 LT |
1782 | /* |
1783 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1784 | */ | |
d05f3169 | 1785 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 1786 | unsigned long address) |
1da177e4 LT |
1787 | { |
1788 | int error; | |
1789 | ||
1790 | /* | |
1791 | * We must make sure the anon_vma is allocated | |
1792 | * so that the anon_vma locking is not a noop. | |
1793 | */ | |
1794 | if (unlikely(anon_vma_prepare(vma))) | |
1795 | return -ENOMEM; | |
8869477a EP |
1796 | |
1797 | address &= PAGE_MASK; | |
88c3f7a8 | 1798 | error = security_file_mmap(NULL, 0, 0, 0, address, 1); |
8869477a EP |
1799 | if (error) |
1800 | return error; | |
1801 | ||
bb4a340e | 1802 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1803 | |
1804 | /* | |
1805 | * vma->vm_start/vm_end cannot change under us because the caller | |
1806 | * is required to hold the mmap_sem in read mode. We need the | |
1807 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1808 | */ | |
1da177e4 LT |
1809 | |
1810 | /* Somebody else might have raced and expanded it already */ | |
1811 | if (address < vma->vm_start) { | |
1812 | unsigned long size, grow; | |
1813 | ||
1814 | size = vma->vm_end - address; | |
1815 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1816 | ||
a626ca6a LT |
1817 | error = -ENOMEM; |
1818 | if (grow <= vma->vm_pgoff) { | |
1819 | error = acct_stack_growth(vma, size, grow); | |
1820 | if (!error) { | |
1821 | vma->vm_start = address; | |
1822 | vma->vm_pgoff -= grow; | |
1823 | perf_event_mmap(vma); | |
1824 | } | |
1da177e4 LT |
1825 | } |
1826 | } | |
bb4a340e | 1827 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1828 | khugepaged_enter_vma_merge(vma); |
1da177e4 LT |
1829 | return error; |
1830 | } | |
1831 | ||
b6a2fea3 OW |
1832 | #ifdef CONFIG_STACK_GROWSUP |
1833 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1834 | { | |
1835 | return expand_upwards(vma, address); | |
1836 | } | |
1837 | ||
1838 | struct vm_area_struct * | |
1839 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1840 | { | |
1841 | struct vm_area_struct *vma, *prev; | |
1842 | ||
1843 | addr &= PAGE_MASK; | |
1844 | vma = find_vma_prev(mm, addr, &prev); | |
1845 | if (vma && (vma->vm_start <= addr)) | |
1846 | return vma; | |
1c127185 | 1847 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 1848 | return NULL; |
ba470de4 | 1849 | if (prev->vm_flags & VM_LOCKED) { |
c58267c3 | 1850 | mlock_vma_pages_range(prev, addr, prev->vm_end); |
ba470de4 | 1851 | } |
b6a2fea3 OW |
1852 | return prev; |
1853 | } | |
1854 | #else | |
1855 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1856 | { | |
1857 | return expand_downwards(vma, address); | |
1858 | } | |
1859 | ||
1da177e4 LT |
1860 | struct vm_area_struct * |
1861 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1862 | { | |
1863 | struct vm_area_struct * vma; | |
1864 | unsigned long start; | |
1865 | ||
1866 | addr &= PAGE_MASK; | |
1867 | vma = find_vma(mm,addr); | |
1868 | if (!vma) | |
1869 | return NULL; | |
1870 | if (vma->vm_start <= addr) | |
1871 | return vma; | |
1872 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1873 | return NULL; | |
1874 | start = vma->vm_start; | |
1875 | if (expand_stack(vma, addr)) | |
1876 | return NULL; | |
ba470de4 | 1877 | if (vma->vm_flags & VM_LOCKED) { |
c58267c3 | 1878 | mlock_vma_pages_range(vma, addr, start); |
ba470de4 | 1879 | } |
1da177e4 LT |
1880 | return vma; |
1881 | } | |
1882 | #endif | |
1883 | ||
1da177e4 | 1884 | /* |
2c0b3814 | 1885 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1886 | * so release them, and do the vma updates. |
2c0b3814 HD |
1887 | * |
1888 | * Called with the mm semaphore held. | |
1da177e4 | 1889 | */ |
2c0b3814 | 1890 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1891 | { |
365e9c87 HD |
1892 | /* Update high watermark before we lower total_vm */ |
1893 | update_hiwater_vm(mm); | |
1da177e4 | 1894 | do { |
2c0b3814 HD |
1895 | long nrpages = vma_pages(vma); |
1896 | ||
1897 | mm->total_vm -= nrpages; | |
2c0b3814 | 1898 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 1899 | vma = remove_vma(vma); |
146425a3 | 1900 | } while (vma); |
1da177e4 LT |
1901 | validate_mm(mm); |
1902 | } | |
1903 | ||
1904 | /* | |
1905 | * Get rid of page table information in the indicated region. | |
1906 | * | |
f10df686 | 1907 | * Called with the mm semaphore held. |
1da177e4 LT |
1908 | */ |
1909 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1910 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1911 | unsigned long start, unsigned long end) | |
1da177e4 | 1912 | { |
e0da382c | 1913 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
d16dfc55 | 1914 | struct mmu_gather tlb; |
1da177e4 LT |
1915 | unsigned long nr_accounted = 0; |
1916 | ||
1917 | lru_add_drain(); | |
d16dfc55 | 1918 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1919 | update_hiwater_rss(mm); |
508034a3 | 1920 | unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); |
1da177e4 | 1921 | vm_unacct_memory(nr_accounted); |
d16dfc55 PZ |
1922 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
1923 | next ? next->vm_start : 0); | |
1924 | tlb_finish_mmu(&tlb, start, end); | |
1da177e4 LT |
1925 | } |
1926 | ||
1927 | /* | |
1928 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1929 | * vma list as we go.. | |
1930 | */ | |
1931 | static void | |
1932 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1933 | struct vm_area_struct *prev, unsigned long end) | |
1934 | { | |
1935 | struct vm_area_struct **insertion_point; | |
1936 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1937 | unsigned long addr; |
1da177e4 LT |
1938 | |
1939 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 1940 | vma->vm_prev = NULL; |
1da177e4 LT |
1941 | do { |
1942 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1943 | mm->map_count--; | |
1944 | tail_vma = vma; | |
1945 | vma = vma->vm_next; | |
1946 | } while (vma && vma->vm_start < end); | |
1947 | *insertion_point = vma; | |
297c5eee LT |
1948 | if (vma) |
1949 | vma->vm_prev = prev; | |
1da177e4 | 1950 | tail_vma->vm_next = NULL; |
1363c3cd WW |
1951 | if (mm->unmap_area == arch_unmap_area) |
1952 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1953 | else | |
1954 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1955 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1956 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1957 | } | |
1958 | ||
1959 | /* | |
659ace58 KM |
1960 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
1961 | * munmap path where it doesn't make sense to fail. | |
1da177e4 | 1962 | */ |
659ace58 | 1963 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1da177e4 LT |
1964 | unsigned long addr, int new_below) |
1965 | { | |
1966 | struct mempolicy *pol; | |
1967 | struct vm_area_struct *new; | |
5beb4930 | 1968 | int err = -ENOMEM; |
1da177e4 | 1969 | |
a5516438 AK |
1970 | if (is_vm_hugetlb_page(vma) && (addr & |
1971 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
1972 | return -EINVAL; |
1973 | ||
e94b1766 | 1974 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 1975 | if (!new) |
5beb4930 | 1976 | goto out_err; |
1da177e4 LT |
1977 | |
1978 | /* most fields are the same, copy all, and then fixup */ | |
1979 | *new = *vma; | |
1980 | ||
5beb4930 RR |
1981 | INIT_LIST_HEAD(&new->anon_vma_chain); |
1982 | ||
1da177e4 LT |
1983 | if (new_below) |
1984 | new->vm_end = addr; | |
1985 | else { | |
1986 | new->vm_start = addr; | |
1987 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
1988 | } | |
1989 | ||
846a16bf | 1990 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 | 1991 | if (IS_ERR(pol)) { |
5beb4930 RR |
1992 | err = PTR_ERR(pol); |
1993 | goto out_free_vma; | |
1da177e4 LT |
1994 | } |
1995 | vma_set_policy(new, pol); | |
1996 | ||
5beb4930 RR |
1997 | if (anon_vma_clone(new, vma)) |
1998 | goto out_free_mpol; | |
1999 | ||
925d1c40 | 2000 | if (new->vm_file) { |
1da177e4 | 2001 | get_file(new->vm_file); |
925d1c40 MH |
2002 | if (vma->vm_flags & VM_EXECUTABLE) |
2003 | added_exe_file_vma(mm); | |
2004 | } | |
1da177e4 LT |
2005 | |
2006 | if (new->vm_ops && new->vm_ops->open) | |
2007 | new->vm_ops->open(new); | |
2008 | ||
2009 | if (new_below) | |
5beb4930 | 2010 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
2011 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
2012 | else | |
5beb4930 | 2013 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 2014 | |
5beb4930 RR |
2015 | /* Success. */ |
2016 | if (!err) | |
2017 | return 0; | |
2018 | ||
2019 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
2020 | if (new->vm_ops && new->vm_ops->close) |
2021 | new->vm_ops->close(new); | |
5beb4930 RR |
2022 | if (new->vm_file) { |
2023 | if (vma->vm_flags & VM_EXECUTABLE) | |
2024 | removed_exe_file_vma(mm); | |
2025 | fput(new->vm_file); | |
2026 | } | |
2aeadc30 | 2027 | unlink_anon_vmas(new); |
5beb4930 RR |
2028 | out_free_mpol: |
2029 | mpol_put(pol); | |
2030 | out_free_vma: | |
2031 | kmem_cache_free(vm_area_cachep, new); | |
2032 | out_err: | |
2033 | return err; | |
1da177e4 LT |
2034 | } |
2035 | ||
659ace58 KM |
2036 | /* |
2037 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2038 | * either for the first part or the tail. | |
2039 | */ | |
2040 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2041 | unsigned long addr, int new_below) | |
2042 | { | |
2043 | if (mm->map_count >= sysctl_max_map_count) | |
2044 | return -ENOMEM; | |
2045 | ||
2046 | return __split_vma(mm, vma, addr, new_below); | |
2047 | } | |
2048 | ||
1da177e4 LT |
2049 | /* Munmap is split into 2 main parts -- this part which finds |
2050 | * what needs doing, and the areas themselves, which do the | |
2051 | * work. This now handles partial unmappings. | |
2052 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
2053 | */ | |
2054 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
2055 | { | |
2056 | unsigned long end; | |
146425a3 | 2057 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
2058 | |
2059 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
2060 | return -EINVAL; | |
2061 | ||
2062 | if ((len = PAGE_ALIGN(len)) == 0) | |
2063 | return -EINVAL; | |
2064 | ||
2065 | /* Find the first overlapping VMA */ | |
9be34c9d | 2066 | vma = find_vma(mm, start); |
146425a3 | 2067 | if (!vma) |
1da177e4 | 2068 | return 0; |
9be34c9d | 2069 | prev = vma->vm_prev; |
146425a3 | 2070 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2071 | |
2072 | /* if it doesn't overlap, we have nothing.. */ | |
2073 | end = start + len; | |
146425a3 | 2074 | if (vma->vm_start >= end) |
1da177e4 LT |
2075 | return 0; |
2076 | ||
2077 | /* | |
2078 | * If we need to split any vma, do it now to save pain later. | |
2079 | * | |
2080 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2081 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2082 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2083 | */ | |
146425a3 | 2084 | if (start > vma->vm_start) { |
659ace58 KM |
2085 | int error; |
2086 | ||
2087 | /* | |
2088 | * Make sure that map_count on return from munmap() will | |
2089 | * not exceed its limit; but let map_count go just above | |
2090 | * its limit temporarily, to help free resources as expected. | |
2091 | */ | |
2092 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2093 | return -ENOMEM; | |
2094 | ||
2095 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2096 | if (error) |
2097 | return error; | |
146425a3 | 2098 | prev = vma; |
1da177e4 LT |
2099 | } |
2100 | ||
2101 | /* Does it split the last one? */ | |
2102 | last = find_vma(mm, end); | |
2103 | if (last && end > last->vm_start) { | |
659ace58 | 2104 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2105 | if (error) |
2106 | return error; | |
2107 | } | |
146425a3 | 2108 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 2109 | |
ba470de4 RR |
2110 | /* |
2111 | * unlock any mlock()ed ranges before detaching vmas | |
2112 | */ | |
2113 | if (mm->locked_vm) { | |
2114 | struct vm_area_struct *tmp = vma; | |
2115 | while (tmp && tmp->vm_start < end) { | |
2116 | if (tmp->vm_flags & VM_LOCKED) { | |
2117 | mm->locked_vm -= vma_pages(tmp); | |
2118 | munlock_vma_pages_all(tmp); | |
2119 | } | |
2120 | tmp = tmp->vm_next; | |
2121 | } | |
2122 | } | |
2123 | ||
1da177e4 LT |
2124 | /* |
2125 | * Remove the vma's, and unmap the actual pages | |
2126 | */ | |
146425a3 HD |
2127 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2128 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
2129 | |
2130 | /* Fix up all other VM information */ | |
2c0b3814 | 2131 | remove_vma_list(mm, vma); |
1da177e4 LT |
2132 | |
2133 | return 0; | |
2134 | } | |
1da177e4 LT |
2135 | EXPORT_SYMBOL(do_munmap); |
2136 | ||
bfce281c | 2137 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2138 | { |
2139 | int ret; | |
bfce281c | 2140 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
2141 | |
2142 | down_write(&mm->mmap_sem); | |
a46ef99d | 2143 | ret = do_munmap(mm, start, len); |
1da177e4 LT |
2144 | up_write(&mm->mmap_sem); |
2145 | return ret; | |
2146 | } | |
a46ef99d LT |
2147 | EXPORT_SYMBOL(vm_munmap); |
2148 | ||
2149 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2150 | { | |
2151 | profile_munmap(addr); | |
bfce281c | 2152 | return vm_munmap(addr, len); |
a46ef99d | 2153 | } |
1da177e4 LT |
2154 | |
2155 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
2156 | { | |
a241ec65 | 2157 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2158 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2159 | WARN_ON(1); | |
2160 | up_read(&mm->mmap_sem); | |
2161 | } | |
2162 | #endif | |
2163 | } | |
2164 | ||
2165 | /* | |
2166 | * this is really a simplified "do_mmap". it only handles | |
2167 | * anonymous maps. eventually we may be able to do some | |
2168 | * brk-specific accounting here. | |
2169 | */ | |
e4eb1ff6 | 2170 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
1da177e4 LT |
2171 | { |
2172 | struct mm_struct * mm = current->mm; | |
2173 | struct vm_area_struct * vma, * prev; | |
2174 | unsigned long flags; | |
2175 | struct rb_node ** rb_link, * rb_parent; | |
2176 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 2177 | int error; |
1da177e4 LT |
2178 | |
2179 | len = PAGE_ALIGN(len); | |
2180 | if (!len) | |
2181 | return addr; | |
2182 | ||
88c3f7a8 | 2183 | error = security_file_mmap(NULL, 0, 0, 0, addr, 1); |
5a211a5d EP |
2184 | if (error) |
2185 | return error; | |
2186 | ||
3a459756 KK |
2187 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2188 | ||
2c6a1016 AV |
2189 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
2190 | if (error & ~PAGE_MASK) | |
3a459756 KK |
2191 | return error; |
2192 | ||
1da177e4 LT |
2193 | /* |
2194 | * mlock MCL_FUTURE? | |
2195 | */ | |
2196 | if (mm->def_flags & VM_LOCKED) { | |
2197 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
2198 | locked = len >> PAGE_SHIFT; |
2199 | locked += mm->locked_vm; | |
59e99e5b | 2200 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 2201 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
2202 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
2203 | return -EAGAIN; | |
2204 | } | |
2205 | ||
2206 | /* | |
2207 | * mm->mmap_sem is required to protect against another thread | |
2208 | * changing the mappings in case we sleep. | |
2209 | */ | |
2210 | verify_mm_writelocked(mm); | |
2211 | ||
2212 | /* | |
2213 | * Clear old maps. this also does some error checking for us | |
2214 | */ | |
2215 | munmap_back: | |
2216 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2217 | if (vma && vma->vm_start < addr + len) { | |
2218 | if (do_munmap(mm, addr, len)) | |
2219 | return -ENOMEM; | |
2220 | goto munmap_back; | |
2221 | } | |
2222 | ||
2223 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2224 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2225 | return -ENOMEM; |
2226 | ||
2227 | if (mm->map_count > sysctl_max_map_count) | |
2228 | return -ENOMEM; | |
2229 | ||
191c5424 | 2230 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2231 | return -ENOMEM; |
2232 | ||
1da177e4 | 2233 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2234 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2235 | NULL, NULL, pgoff, NULL); | |
2236 | if (vma) | |
1da177e4 LT |
2237 | goto out; |
2238 | ||
2239 | /* | |
2240 | * create a vma struct for an anonymous mapping | |
2241 | */ | |
c5e3b83e | 2242 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2243 | if (!vma) { |
2244 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2245 | return -ENOMEM; | |
2246 | } | |
1da177e4 | 2247 | |
5beb4930 | 2248 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2249 | vma->vm_mm = mm; |
2250 | vma->vm_start = addr; | |
2251 | vma->vm_end = addr + len; | |
2252 | vma->vm_pgoff = pgoff; | |
2253 | vma->vm_flags = flags; | |
3ed75eb8 | 2254 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2255 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2256 | out: | |
3af9e859 | 2257 | perf_event_mmap(vma); |
1da177e4 LT |
2258 | mm->total_vm += len >> PAGE_SHIFT; |
2259 | if (flags & VM_LOCKED) { | |
ba470de4 RR |
2260 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
2261 | mm->locked_vm += (len >> PAGE_SHIFT); | |
1da177e4 LT |
2262 | } |
2263 | return addr; | |
2264 | } | |
2265 | ||
e4eb1ff6 LT |
2266 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
2267 | { | |
2268 | struct mm_struct *mm = current->mm; | |
2269 | unsigned long ret; | |
2270 | ||
2271 | down_write(&mm->mmap_sem); | |
2272 | ret = do_brk(addr, len); | |
2273 | up_write(&mm->mmap_sem); | |
2274 | return ret; | |
2275 | } | |
2276 | EXPORT_SYMBOL(vm_brk); | |
1da177e4 LT |
2277 | |
2278 | /* Release all mmaps. */ | |
2279 | void exit_mmap(struct mm_struct *mm) | |
2280 | { | |
d16dfc55 | 2281 | struct mmu_gather tlb; |
ba470de4 | 2282 | struct vm_area_struct *vma; |
1da177e4 LT |
2283 | unsigned long nr_accounted = 0; |
2284 | ||
d6dd61c8 | 2285 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2286 | mmu_notifier_release(mm); |
d6dd61c8 | 2287 | |
ba470de4 RR |
2288 | if (mm->locked_vm) { |
2289 | vma = mm->mmap; | |
2290 | while (vma) { | |
2291 | if (vma->vm_flags & VM_LOCKED) | |
2292 | munlock_vma_pages_all(vma); | |
2293 | vma = vma->vm_next; | |
2294 | } | |
2295 | } | |
9480c53e JF |
2296 | |
2297 | arch_exit_mmap(mm); | |
2298 | ||
ba470de4 | 2299 | vma = mm->mmap; |
9480c53e JF |
2300 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2301 | return; | |
2302 | ||
1da177e4 | 2303 | lru_add_drain(); |
1da177e4 | 2304 | flush_cache_mm(mm); |
d16dfc55 | 2305 | tlb_gather_mmu(&tlb, mm, 1); |
901608d9 | 2306 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2307 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
6e8bb019 | 2308 | unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); |
1da177e4 | 2309 | vm_unacct_memory(nr_accounted); |
9ba69294 | 2310 | |
d16dfc55 | 2311 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
853f5e26 | 2312 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 2313 | |
1da177e4 | 2314 | /* |
8f4f8c16 HD |
2315 | * Walk the list again, actually closing and freeing it, |
2316 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2317 | */ |
a8fb5618 HD |
2318 | while (vma) |
2319 | vma = remove_vma(vma); | |
e0da382c | 2320 | |
e2cdef8c | 2321 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
2322 | } |
2323 | ||
2324 | /* Insert vm structure into process list sorted by address | |
2325 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
3d48ae45 | 2326 | * then i_mmap_mutex is taken here. |
1da177e4 LT |
2327 | */ |
2328 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) | |
2329 | { | |
2330 | struct vm_area_struct * __vma, * prev; | |
2331 | struct rb_node ** rb_link, * rb_parent; | |
2332 | ||
2333 | /* | |
2334 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2335 | * until its first write fault, when page's anon_vma and index | |
2336 | * are set. But now set the vm_pgoff it will almost certainly | |
2337 | * end up with (unless mremap moves it elsewhere before that | |
2338 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2339 | * | |
2340 | * By setting it to reflect the virtual start address of the | |
2341 | * vma, merges and splits can happen in a seamless way, just | |
2342 | * using the existing file pgoff checks and manipulations. | |
2343 | * Similarly in do_mmap_pgoff and in do_brk. | |
2344 | */ | |
2345 | if (!vma->vm_file) { | |
2346 | BUG_ON(vma->anon_vma); | |
2347 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2348 | } | |
2349 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); | |
2350 | if (__vma && __vma->vm_start < vma->vm_end) | |
2351 | return -ENOMEM; | |
2fd4ef85 | 2352 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2353 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2354 | return -ENOMEM; |
1da177e4 LT |
2355 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2356 | return 0; | |
2357 | } | |
2358 | ||
2359 | /* | |
2360 | * Copy the vma structure to a new location in the same mm, | |
2361 | * prior to moving page table entries, to effect an mremap move. | |
2362 | */ | |
2363 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
2364 | unsigned long addr, unsigned long len, pgoff_t pgoff) | |
2365 | { | |
2366 | struct vm_area_struct *vma = *vmap; | |
2367 | unsigned long vma_start = vma->vm_start; | |
2368 | struct mm_struct *mm = vma->vm_mm; | |
2369 | struct vm_area_struct *new_vma, *prev; | |
2370 | struct rb_node **rb_link, *rb_parent; | |
2371 | struct mempolicy *pol; | |
948f017b | 2372 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
2373 | |
2374 | /* | |
2375 | * If anonymous vma has not yet been faulted, update new pgoff | |
2376 | * to match new location, to increase its chance of merging. | |
2377 | */ | |
948f017b | 2378 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
1da177e4 | 2379 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
2380 | faulted_in_anon_vma = false; |
2381 | } | |
1da177e4 LT |
2382 | |
2383 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); | |
2384 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, | |
2385 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2386 | if (new_vma) { | |
2387 | /* | |
2388 | * Source vma may have been merged into new_vma | |
2389 | */ | |
948f017b AA |
2390 | if (unlikely(vma_start >= new_vma->vm_start && |
2391 | vma_start < new_vma->vm_end)) { | |
2392 | /* | |
2393 | * The only way we can get a vma_merge with | |
2394 | * self during an mremap is if the vma hasn't | |
2395 | * been faulted in yet and we were allowed to | |
2396 | * reset the dst vma->vm_pgoff to the | |
2397 | * destination address of the mremap to allow | |
2398 | * the merge to happen. mremap must change the | |
2399 | * vm_pgoff linearity between src and dst vmas | |
2400 | * (in turn preventing a vma_merge) to be | |
2401 | * safe. It is only safe to keep the vm_pgoff | |
2402 | * linear if there are no pages mapped yet. | |
2403 | */ | |
2404 | VM_BUG_ON(faulted_in_anon_vma); | |
1da177e4 | 2405 | *vmap = new_vma; |
948f017b AA |
2406 | } else |
2407 | anon_vma_moveto_tail(new_vma); | |
1da177e4 | 2408 | } else { |
e94b1766 | 2409 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2410 | if (new_vma) { |
2411 | *new_vma = *vma; | |
846a16bf | 2412 | pol = mpol_dup(vma_policy(vma)); |
5beb4930 RR |
2413 | if (IS_ERR(pol)) |
2414 | goto out_free_vma; | |
2415 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); | |
2416 | if (anon_vma_clone(new_vma, vma)) | |
2417 | goto out_free_mempol; | |
1da177e4 LT |
2418 | vma_set_policy(new_vma, pol); |
2419 | new_vma->vm_start = addr; | |
2420 | new_vma->vm_end = addr + len; | |
2421 | new_vma->vm_pgoff = pgoff; | |
925d1c40 | 2422 | if (new_vma->vm_file) { |
1da177e4 | 2423 | get_file(new_vma->vm_file); |
925d1c40 MH |
2424 | if (vma->vm_flags & VM_EXECUTABLE) |
2425 | added_exe_file_vma(mm); | |
2426 | } | |
1da177e4 LT |
2427 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
2428 | new_vma->vm_ops->open(new_vma); | |
2429 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
2430 | } | |
2431 | } | |
2432 | return new_vma; | |
5beb4930 RR |
2433 | |
2434 | out_free_mempol: | |
2435 | mpol_put(pol); | |
2436 | out_free_vma: | |
2437 | kmem_cache_free(vm_area_cachep, new_vma); | |
2438 | return NULL; | |
1da177e4 | 2439 | } |
119f657c | 2440 | |
2441 | /* | |
2442 | * Return true if the calling process may expand its vm space by the passed | |
2443 | * number of pages | |
2444 | */ | |
2445 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2446 | { | |
2447 | unsigned long cur = mm->total_vm; /* pages */ | |
2448 | unsigned long lim; | |
2449 | ||
59e99e5b | 2450 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
119f657c | 2451 | |
2452 | if (cur + npages > lim) | |
2453 | return 0; | |
2454 | return 1; | |
2455 | } | |
fa5dc22f RM |
2456 | |
2457 | ||
b1d0e4f5 NP |
2458 | static int special_mapping_fault(struct vm_area_struct *vma, |
2459 | struct vm_fault *vmf) | |
fa5dc22f | 2460 | { |
b1d0e4f5 | 2461 | pgoff_t pgoff; |
fa5dc22f RM |
2462 | struct page **pages; |
2463 | ||
b1d0e4f5 NP |
2464 | /* |
2465 | * special mappings have no vm_file, and in that case, the mm | |
2466 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2467 | * We are allowed to do this because we are the mm; do not copy | |
2468 | * this code into drivers! | |
2469 | */ | |
2470 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2471 | |
b1d0e4f5 NP |
2472 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2473 | pgoff--; | |
fa5dc22f RM |
2474 | |
2475 | if (*pages) { | |
2476 | struct page *page = *pages; | |
2477 | get_page(page); | |
b1d0e4f5 NP |
2478 | vmf->page = page; |
2479 | return 0; | |
fa5dc22f RM |
2480 | } |
2481 | ||
b1d0e4f5 | 2482 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2483 | } |
2484 | ||
2485 | /* | |
2486 | * Having a close hook prevents vma merging regardless of flags. | |
2487 | */ | |
2488 | static void special_mapping_close(struct vm_area_struct *vma) | |
2489 | { | |
2490 | } | |
2491 | ||
f0f37e2f | 2492 | static const struct vm_operations_struct special_mapping_vmops = { |
fa5dc22f | 2493 | .close = special_mapping_close, |
b1d0e4f5 | 2494 | .fault = special_mapping_fault, |
fa5dc22f RM |
2495 | }; |
2496 | ||
2497 | /* | |
2498 | * Called with mm->mmap_sem held for writing. | |
2499 | * Insert a new vma covering the given region, with the given flags. | |
2500 | * Its pages are supplied by the given array of struct page *. | |
2501 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2502 | * The region past the last page supplied will always produce SIGBUS. | |
2503 | * The array pointer and the pages it points to are assumed to stay alive | |
2504 | * for as long as this mapping might exist. | |
2505 | */ | |
2506 | int install_special_mapping(struct mm_struct *mm, | |
2507 | unsigned long addr, unsigned long len, | |
2508 | unsigned long vm_flags, struct page **pages) | |
2509 | { | |
462e635e | 2510 | int ret; |
fa5dc22f RM |
2511 | struct vm_area_struct *vma; |
2512 | ||
2513 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2514 | if (unlikely(vma == NULL)) | |
2515 | return -ENOMEM; | |
2516 | ||
5beb4930 | 2517 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
2518 | vma->vm_mm = mm; |
2519 | vma->vm_start = addr; | |
2520 | vma->vm_end = addr + len; | |
2521 | ||
2f98735c | 2522 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
3ed75eb8 | 2523 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2524 | |
2525 | vma->vm_ops = &special_mapping_vmops; | |
2526 | vma->vm_private_data = pages; | |
2527 | ||
462e635e TO |
2528 | ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1); |
2529 | if (ret) | |
2530 | goto out; | |
2531 | ||
2532 | ret = insert_vm_struct(mm, vma); | |
2533 | if (ret) | |
2534 | goto out; | |
fa5dc22f RM |
2535 | |
2536 | mm->total_vm += len >> PAGE_SHIFT; | |
2537 | ||
cdd6c482 | 2538 | perf_event_mmap(vma); |
089dd79d | 2539 | |
fa5dc22f | 2540 | return 0; |
462e635e TO |
2541 | |
2542 | out: | |
2543 | kmem_cache_free(vm_area_cachep, vma); | |
2544 | return ret; | |
fa5dc22f | 2545 | } |
7906d00c AA |
2546 | |
2547 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
2548 | ||
454ed842 | 2549 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 2550 | { |
012f1800 | 2551 | if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { |
7906d00c AA |
2552 | /* |
2553 | * The LSB of head.next can't change from under us | |
2554 | * because we hold the mm_all_locks_mutex. | |
2555 | */ | |
2b575eb6 | 2556 | mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem); |
7906d00c AA |
2557 | /* |
2558 | * We can safely modify head.next after taking the | |
2b575eb6 | 2559 | * anon_vma->root->mutex. If some other vma in this mm shares |
7906d00c AA |
2560 | * the same anon_vma we won't take it again. |
2561 | * | |
2562 | * No need of atomic instructions here, head.next | |
2563 | * can't change from under us thanks to the | |
2b575eb6 | 2564 | * anon_vma->root->mutex. |
7906d00c AA |
2565 | */ |
2566 | if (__test_and_set_bit(0, (unsigned long *) | |
012f1800 | 2567 | &anon_vma->root->head.next)) |
7906d00c AA |
2568 | BUG(); |
2569 | } | |
2570 | } | |
2571 | ||
454ed842 | 2572 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
2573 | { |
2574 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2575 | /* | |
2576 | * AS_MM_ALL_LOCKS can't change from under us because | |
2577 | * we hold the mm_all_locks_mutex. | |
2578 | * | |
2579 | * Operations on ->flags have to be atomic because | |
2580 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
2581 | * mm_all_locks_mutex, there may be other cpus | |
2582 | * changing other bitflags in parallel to us. | |
2583 | */ | |
2584 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
2585 | BUG(); | |
3d48ae45 | 2586 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
7906d00c AA |
2587 | } |
2588 | } | |
2589 | ||
2590 | /* | |
2591 | * This operation locks against the VM for all pte/vma/mm related | |
2592 | * operations that could ever happen on a certain mm. This includes | |
2593 | * vmtruncate, try_to_unmap, and all page faults. | |
2594 | * | |
2595 | * The caller must take the mmap_sem in write mode before calling | |
2596 | * mm_take_all_locks(). The caller isn't allowed to release the | |
2597 | * mmap_sem until mm_drop_all_locks() returns. | |
2598 | * | |
2599 | * mmap_sem in write mode is required in order to block all operations | |
2600 | * that could modify pagetables and free pages without need of | |
2601 | * altering the vma layout (for example populate_range() with | |
2602 | * nonlinear vmas). It's also needed in write mode to avoid new | |
2603 | * anon_vmas to be associated with existing vmas. | |
2604 | * | |
2605 | * A single task can't take more than one mm_take_all_locks() in a row | |
2606 | * or it would deadlock. | |
2607 | * | |
2608 | * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in | |
2609 | * mapping->flags avoid to take the same lock twice, if more than one | |
2610 | * vma in this mm is backed by the same anon_vma or address_space. | |
2611 | * | |
2612 | * We can take all the locks in random order because the VM code | |
2b575eb6 | 2613 | * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never |
7906d00c AA |
2614 | * takes more than one of them in a row. Secondly we're protected |
2615 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
2616 | * | |
2617 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
2618 | * that may have to take thousand of locks. | |
2619 | * | |
2620 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
2621 | */ | |
2622 | int mm_take_all_locks(struct mm_struct *mm) | |
2623 | { | |
2624 | struct vm_area_struct *vma; | |
5beb4930 | 2625 | struct anon_vma_chain *avc; |
7906d00c AA |
2626 | |
2627 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2628 | ||
2629 | mutex_lock(&mm_all_locks_mutex); | |
2630 | ||
2631 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2632 | if (signal_pending(current)) | |
2633 | goto out_unlock; | |
7906d00c | 2634 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 2635 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 2636 | } |
7cd5a02f PZ |
2637 | |
2638 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2639 | if (signal_pending(current)) | |
2640 | goto out_unlock; | |
2641 | if (vma->anon_vma) | |
5beb4930 RR |
2642 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2643 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 2644 | } |
7cd5a02f | 2645 | |
584cff54 | 2646 | return 0; |
7906d00c AA |
2647 | |
2648 | out_unlock: | |
584cff54 KC |
2649 | mm_drop_all_locks(mm); |
2650 | return -EINTR; | |
7906d00c AA |
2651 | } |
2652 | ||
2653 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
2654 | { | |
012f1800 | 2655 | if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { |
7906d00c AA |
2656 | /* |
2657 | * The LSB of head.next can't change to 0 from under | |
2658 | * us because we hold the mm_all_locks_mutex. | |
2659 | * | |
2660 | * We must however clear the bitflag before unlocking | |
2661 | * the vma so the users using the anon_vma->head will | |
2662 | * never see our bitflag. | |
2663 | * | |
2664 | * No need of atomic instructions here, head.next | |
2665 | * can't change from under us until we release the | |
2b575eb6 | 2666 | * anon_vma->root->mutex. |
7906d00c AA |
2667 | */ |
2668 | if (!__test_and_clear_bit(0, (unsigned long *) | |
012f1800 | 2669 | &anon_vma->root->head.next)) |
7906d00c | 2670 | BUG(); |
cba48b98 | 2671 | anon_vma_unlock(anon_vma); |
7906d00c AA |
2672 | } |
2673 | } | |
2674 | ||
2675 | static void vm_unlock_mapping(struct address_space *mapping) | |
2676 | { | |
2677 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2678 | /* | |
2679 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
2680 | * because we hold the mm_all_locks_mutex. | |
2681 | */ | |
3d48ae45 | 2682 | mutex_unlock(&mapping->i_mmap_mutex); |
7906d00c AA |
2683 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
2684 | &mapping->flags)) | |
2685 | BUG(); | |
2686 | } | |
2687 | } | |
2688 | ||
2689 | /* | |
2690 | * The mmap_sem cannot be released by the caller until | |
2691 | * mm_drop_all_locks() returns. | |
2692 | */ | |
2693 | void mm_drop_all_locks(struct mm_struct *mm) | |
2694 | { | |
2695 | struct vm_area_struct *vma; | |
5beb4930 | 2696 | struct anon_vma_chain *avc; |
7906d00c AA |
2697 | |
2698 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2699 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
2700 | ||
2701 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2702 | if (vma->anon_vma) | |
5beb4930 RR |
2703 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2704 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
2705 | if (vma->vm_file && vma->vm_file->f_mapping) |
2706 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
2707 | } | |
2708 | ||
2709 | mutex_unlock(&mm_all_locks_mutex); | |
2710 | } | |
8feae131 DH |
2711 | |
2712 | /* | |
2713 | * initialise the VMA slab | |
2714 | */ | |
2715 | void __init mmap_init(void) | |
2716 | { | |
00a62ce9 KM |
2717 | int ret; |
2718 | ||
2719 | ret = percpu_counter_init(&vm_committed_as, 0); | |
2720 | VM_BUG_ON(ret); | |
8feae131 | 2721 | } |