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> |
2b144498 | 33 | #include <linux/uprobes.h> |
1da177e4 LT |
34 | |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/cacheflush.h> | |
37 | #include <asm/tlb.h> | |
d6dd61c8 | 38 | #include <asm/mmu_context.h> |
1da177e4 | 39 | |
42b77728 JB |
40 | #include "internal.h" |
41 | ||
3a459756 KK |
42 | #ifndef arch_mmap_check |
43 | #define arch_mmap_check(addr, len, flags) (0) | |
44 | #endif | |
45 | ||
08e7d9b5 MS |
46 | #ifndef arch_rebalance_pgtables |
47 | #define arch_rebalance_pgtables(addr, len) (addr) | |
48 | #endif | |
49 | ||
e0da382c HD |
50 | static void unmap_region(struct mm_struct *mm, |
51 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
52 | unsigned long start, unsigned long end); | |
53 | ||
1da177e4 LT |
54 | /* |
55 | * WARNING: the debugging will use recursive algorithms so never enable this | |
56 | * unless you know what you are doing. | |
57 | */ | |
58 | #undef DEBUG_MM_RB | |
59 | ||
60 | /* description of effects of mapping type and prot in current implementation. | |
61 | * this is due to the limited x86 page protection hardware. The expected | |
62 | * behavior is in parens: | |
63 | * | |
64 | * map_type prot | |
65 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
66 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
67 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
68 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
69 | * | |
70 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
71 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
72 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
73 | * | |
74 | */ | |
75 | pgprot_t protection_map[16] = { | |
76 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
77 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
78 | }; | |
79 | ||
804af2cf HD |
80 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
81 | { | |
b845f313 DK |
82 | return __pgprot(pgprot_val(protection_map[vm_flags & |
83 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
84 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
85 | } |
86 | EXPORT_SYMBOL(vm_get_page_prot); | |
87 | ||
34679d7e SL |
88 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
89 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ | |
c3d8c141 | 90 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
34679d7e SL |
91 | /* |
92 | * Make sure vm_committed_as in one cacheline and not cacheline shared with | |
93 | * other variables. It can be updated by several CPUs frequently. | |
94 | */ | |
95 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; | |
1da177e4 LT |
96 | |
97 | /* | |
98 | * Check that a process has enough memory to allocate a new virtual | |
99 | * mapping. 0 means there is enough memory for the allocation to | |
100 | * succeed and -ENOMEM implies there is not. | |
101 | * | |
102 | * We currently support three overcommit policies, which are set via the | |
103 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
104 | * | |
105 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
106 | * Additional code 2002 Jul 20 by Robert Love. | |
107 | * | |
108 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
109 | * | |
110 | * Note this is a helper function intended to be used by LSMs which | |
111 | * wish to use this logic. | |
112 | */ | |
34b4e4aa | 113 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
114 | { |
115 | unsigned long free, allowed; | |
116 | ||
117 | vm_acct_memory(pages); | |
118 | ||
119 | /* | |
120 | * Sometimes we want to use more memory than we have | |
121 | */ | |
122 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
123 | return 0; | |
124 | ||
125 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
c15bef30 DF |
126 | free = global_page_state(NR_FREE_PAGES); |
127 | free += global_page_state(NR_FILE_PAGES); | |
128 | ||
129 | /* | |
130 | * shmem pages shouldn't be counted as free in this | |
131 | * case, they can't be purged, only swapped out, and | |
132 | * that won't affect the overall amount of available | |
133 | * memory in the system. | |
134 | */ | |
135 | free -= global_page_state(NR_SHMEM); | |
1da177e4 | 136 | |
1da177e4 LT |
137 | free += nr_swap_pages; |
138 | ||
139 | /* | |
140 | * Any slabs which are created with the | |
141 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
142 | * which are reclaimable, under pressure. The dentry | |
143 | * cache and most inode caches should fall into this | |
144 | */ | |
972d1a7b | 145 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 | 146 | |
6d9f7839 HA |
147 | /* |
148 | * Leave reserved pages. The pages are not for anonymous pages. | |
149 | */ | |
c15bef30 | 150 | if (free <= totalreserve_pages) |
6d9f7839 HA |
151 | goto error; |
152 | else | |
c15bef30 | 153 | free -= totalreserve_pages; |
6d9f7839 HA |
154 | |
155 | /* | |
156 | * Leave the last 3% for root | |
157 | */ | |
1da177e4 | 158 | if (!cap_sys_admin) |
c15bef30 | 159 | free -= free / 32; |
1da177e4 LT |
160 | |
161 | if (free > pages) | |
162 | return 0; | |
6d9f7839 HA |
163 | |
164 | goto error; | |
1da177e4 LT |
165 | } |
166 | ||
167 | allowed = (totalram_pages - hugetlb_total_pages()) | |
168 | * sysctl_overcommit_ratio / 100; | |
169 | /* | |
170 | * Leave the last 3% for root | |
171 | */ | |
172 | if (!cap_sys_admin) | |
173 | allowed -= allowed / 32; | |
174 | allowed += total_swap_pages; | |
175 | ||
176 | /* Don't let a single process grow too big: | |
177 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
178 | if (mm) |
179 | allowed -= mm->total_vm / 32; | |
1da177e4 | 180 | |
00a62ce9 | 181 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 182 | return 0; |
6d9f7839 | 183 | error: |
1da177e4 LT |
184 | vm_unacct_memory(pages); |
185 | ||
186 | return -ENOMEM; | |
187 | } | |
188 | ||
1da177e4 | 189 | /* |
3d48ae45 | 190 | * Requires inode->i_mapping->i_mmap_mutex |
1da177e4 LT |
191 | */ |
192 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
193 | struct file *file, struct address_space *mapping) | |
194 | { | |
195 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 196 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
197 | if (vma->vm_flags & VM_SHARED) |
198 | mapping->i_mmap_writable--; | |
199 | ||
200 | flush_dcache_mmap_lock(mapping); | |
201 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
6b2dbba8 | 202 | list_del_init(&vma->shared.nonlinear); |
1da177e4 | 203 | else |
6b2dbba8 | 204 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4 LT |
205 | flush_dcache_mmap_unlock(mapping); |
206 | } | |
207 | ||
208 | /* | |
6b2dbba8 | 209 | * Unlink a file-based vm structure from its interval tree, to hide |
a8fb5618 | 210 | * vma from rmap and vmtruncate before freeing its page tables. |
1da177e4 | 211 | */ |
a8fb5618 | 212 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
213 | { |
214 | struct file *file = vma->vm_file; | |
215 | ||
1da177e4 LT |
216 | if (file) { |
217 | struct address_space *mapping = file->f_mapping; | |
3d48ae45 | 218 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 219 | __remove_shared_vm_struct(vma, file, mapping); |
3d48ae45 | 220 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 221 | } |
a8fb5618 HD |
222 | } |
223 | ||
224 | /* | |
225 | * Close a vm structure and free it, returning the next. | |
226 | */ | |
227 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
228 | { | |
229 | struct vm_area_struct *next = vma->vm_next; | |
230 | ||
a8fb5618 | 231 | might_sleep(); |
1da177e4 LT |
232 | if (vma->vm_ops && vma->vm_ops->close) |
233 | vma->vm_ops->close(vma); | |
e9714acf | 234 | if (vma->vm_file) |
a8fb5618 | 235 | fput(vma->vm_file); |
f0be3d32 | 236 | mpol_put(vma_policy(vma)); |
1da177e4 | 237 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 238 | return next; |
1da177e4 LT |
239 | } |
240 | ||
e4eb1ff6 LT |
241 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
242 | ||
6a6160a7 | 243 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
244 | { |
245 | unsigned long rlim, retval; | |
246 | unsigned long newbrk, oldbrk; | |
247 | struct mm_struct *mm = current->mm; | |
a5b4592c | 248 | unsigned long min_brk; |
1da177e4 LT |
249 | |
250 | down_write(&mm->mmap_sem); | |
251 | ||
a5b4592c | 252 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
253 | /* |
254 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
255 | * randomize_va_space to 2, which will still cause mm->start_brk | |
256 | * to be arbitrarily shifted | |
257 | */ | |
4471a675 | 258 | if (current->brk_randomized) |
5520e894 JK |
259 | min_brk = mm->start_brk; |
260 | else | |
261 | min_brk = mm->end_data; | |
a5b4592c JK |
262 | #else |
263 | min_brk = mm->start_brk; | |
264 | #endif | |
265 | if (brk < min_brk) | |
1da177e4 | 266 | goto out; |
1e624196 RG |
267 | |
268 | /* | |
269 | * Check against rlimit here. If this check is done later after the test | |
270 | * of oldbrk with newbrk then it can escape the test and let the data | |
271 | * segment grow beyond its set limit the in case where the limit is | |
272 | * not page aligned -Ram Gupta | |
273 | */ | |
59e99e5b | 274 | rlim = rlimit(RLIMIT_DATA); |
c1d171a0 JK |
275 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
276 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
277 | goto out; |
278 | ||
1da177e4 LT |
279 | newbrk = PAGE_ALIGN(brk); |
280 | oldbrk = PAGE_ALIGN(mm->brk); | |
281 | if (oldbrk == newbrk) | |
282 | goto set_brk; | |
283 | ||
284 | /* Always allow shrinking brk. */ | |
285 | if (brk <= mm->brk) { | |
286 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
287 | goto set_brk; | |
288 | goto out; | |
289 | } | |
290 | ||
1da177e4 LT |
291 | /* Check against existing mmap mappings. */ |
292 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
293 | goto out; | |
294 | ||
295 | /* Ok, looks good - let it rip. */ | |
296 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
297 | goto out; | |
298 | set_brk: | |
299 | mm->brk = brk; | |
300 | out: | |
301 | retval = mm->brk; | |
302 | up_write(&mm->mmap_sem); | |
303 | return retval; | |
304 | } | |
305 | ||
306 | #ifdef DEBUG_MM_RB | |
307 | static int browse_rb(struct rb_root *root) | |
308 | { | |
309 | int i = 0, j; | |
310 | struct rb_node *nd, *pn = NULL; | |
311 | unsigned long prev = 0, pend = 0; | |
312 | ||
313 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
314 | struct vm_area_struct *vma; | |
315 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
316 | if (vma->vm_start < prev) | |
317 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
318 | if (vma->vm_start < pend) | |
319 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
320 | if (vma->vm_start > vma->vm_end) | |
321 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
322 | i++; | |
323 | pn = nd; | |
d1af65d1 DM |
324 | prev = vma->vm_start; |
325 | pend = vma->vm_end; | |
1da177e4 LT |
326 | } |
327 | j = 0; | |
328 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
329 | j++; | |
330 | } | |
331 | if (i != j) | |
332 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
333 | return i; | |
334 | } | |
335 | ||
336 | void validate_mm(struct mm_struct *mm) | |
337 | { | |
338 | int bug = 0; | |
339 | int i = 0; | |
340 | struct vm_area_struct *tmp = mm->mmap; | |
341 | while (tmp) { | |
342 | tmp = tmp->vm_next; | |
343 | i++; | |
344 | } | |
345 | if (i != mm->map_count) | |
346 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
347 | i = browse_rb(&mm->mm_rb); | |
348 | if (i != mm->map_count) | |
349 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 350 | BUG_ON(bug); |
1da177e4 LT |
351 | } |
352 | #else | |
353 | #define validate_mm(mm) do { } while (0) | |
354 | #endif | |
355 | ||
6597d783 HD |
356 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
357 | unsigned long end, struct vm_area_struct **pprev, | |
358 | struct rb_node ***rb_link, struct rb_node **rb_parent) | |
1da177e4 | 359 | { |
6597d783 | 360 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
1da177e4 LT |
361 | |
362 | __rb_link = &mm->mm_rb.rb_node; | |
363 | rb_prev = __rb_parent = NULL; | |
1da177e4 LT |
364 | |
365 | while (*__rb_link) { | |
366 | struct vm_area_struct *vma_tmp; | |
367 | ||
368 | __rb_parent = *__rb_link; | |
369 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
370 | ||
371 | if (vma_tmp->vm_end > addr) { | |
6597d783 HD |
372 | /* Fail if an existing vma overlaps the area */ |
373 | if (vma_tmp->vm_start < end) | |
374 | return -ENOMEM; | |
1da177e4 LT |
375 | __rb_link = &__rb_parent->rb_left; |
376 | } else { | |
377 | rb_prev = __rb_parent; | |
378 | __rb_link = &__rb_parent->rb_right; | |
379 | } | |
380 | } | |
381 | ||
382 | *pprev = NULL; | |
383 | if (rb_prev) | |
384 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
385 | *rb_link = __rb_link; | |
386 | *rb_parent = __rb_parent; | |
6597d783 | 387 | return 0; |
1da177e4 LT |
388 | } |
389 | ||
1da177e4 LT |
390 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
391 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
392 | { | |
393 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
394 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
395 | } | |
396 | ||
cb8f488c | 397 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 398 | { |
48aae425 | 399 | struct file *file; |
1da177e4 LT |
400 | |
401 | file = vma->vm_file; | |
402 | if (file) { | |
403 | struct address_space *mapping = file->f_mapping; | |
404 | ||
405 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 406 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
407 | if (vma->vm_flags & VM_SHARED) |
408 | mapping->i_mmap_writable++; | |
409 | ||
410 | flush_dcache_mmap_lock(mapping); | |
411 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
412 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
413 | else | |
6b2dbba8 | 414 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4 LT |
415 | flush_dcache_mmap_unlock(mapping); |
416 | } | |
417 | } | |
418 | ||
419 | static void | |
420 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
421 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
422 | struct rb_node *rb_parent) | |
423 | { | |
424 | __vma_link_list(mm, vma, prev, rb_parent); | |
425 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
426 | } |
427 | ||
428 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
429 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
430 | struct rb_node *rb_parent) | |
431 | { | |
432 | struct address_space *mapping = NULL; | |
433 | ||
434 | if (vma->vm_file) | |
435 | mapping = vma->vm_file->f_mapping; | |
436 | ||
97a89413 | 437 | if (mapping) |
3d48ae45 | 438 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 LT |
439 | |
440 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
441 | __vma_link_file(vma); | |
442 | ||
1da177e4 | 443 | if (mapping) |
3d48ae45 | 444 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
445 | |
446 | mm->map_count++; | |
447 | validate_mm(mm); | |
448 | } | |
449 | ||
450 | /* | |
88f6b4c3 | 451 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
6b2dbba8 | 452 | * mm's list and rbtree. It has already been inserted into the interval tree. |
1da177e4 | 453 | */ |
48aae425 | 454 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 455 | { |
6597d783 | 456 | struct vm_area_struct *prev; |
48aae425 | 457 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 458 | |
6597d783 HD |
459 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
460 | &prev, &rb_link, &rb_parent)) | |
461 | BUG(); | |
1da177e4 LT |
462 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
463 | mm->map_count++; | |
464 | } | |
465 | ||
466 | static inline void | |
467 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
468 | struct vm_area_struct *prev) | |
469 | { | |
297c5eee LT |
470 | struct vm_area_struct *next = vma->vm_next; |
471 | ||
472 | prev->vm_next = next; | |
473 | if (next) | |
474 | next->vm_prev = prev; | |
1da177e4 LT |
475 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
476 | if (mm->mmap_cache == vma) | |
477 | mm->mmap_cache = prev; | |
478 | } | |
479 | ||
480 | /* | |
481 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
482 | * is already present in an i_mmap tree without adjusting the tree. | |
483 | * The following helper function should be used when such adjustments | |
484 | * are necessary. The "insert" vma (if any) is to be inserted | |
485 | * before we drop the necessary locks. | |
486 | */ | |
5beb4930 | 487 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
488 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
489 | { | |
490 | struct mm_struct *mm = vma->vm_mm; | |
491 | struct vm_area_struct *next = vma->vm_next; | |
492 | struct vm_area_struct *importer = NULL; | |
493 | struct address_space *mapping = NULL; | |
6b2dbba8 | 494 | struct rb_root *root = NULL; |
012f1800 | 495 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 496 | struct file *file = vma->vm_file; |
1da177e4 LT |
497 | long adjust_next = 0; |
498 | int remove_next = 0; | |
499 | ||
500 | if (next && !insert) { | |
287d97ac LT |
501 | struct vm_area_struct *exporter = NULL; |
502 | ||
1da177e4 LT |
503 | if (end >= next->vm_end) { |
504 | /* | |
505 | * vma expands, overlapping all the next, and | |
506 | * perhaps the one after too (mprotect case 6). | |
507 | */ | |
508 | again: remove_next = 1 + (end > next->vm_end); | |
509 | end = next->vm_end; | |
287d97ac | 510 | exporter = next; |
1da177e4 LT |
511 | importer = vma; |
512 | } else if (end > next->vm_start) { | |
513 | /* | |
514 | * vma expands, overlapping part of the next: | |
515 | * mprotect case 5 shifting the boundary up. | |
516 | */ | |
517 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 518 | exporter = next; |
1da177e4 LT |
519 | importer = vma; |
520 | } else if (end < vma->vm_end) { | |
521 | /* | |
522 | * vma shrinks, and !insert tells it's not | |
523 | * split_vma inserting another: so it must be | |
524 | * mprotect case 4 shifting the boundary down. | |
525 | */ | |
526 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
287d97ac | 527 | exporter = vma; |
1da177e4 LT |
528 | importer = next; |
529 | } | |
1da177e4 | 530 | |
5beb4930 RR |
531 | /* |
532 | * Easily overlooked: when mprotect shifts the boundary, | |
533 | * make sure the expanding vma has anon_vma set if the | |
534 | * shrinking vma had, to cover any anon pages imported. | |
535 | */ | |
287d97ac LT |
536 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
537 | if (anon_vma_clone(importer, exporter)) | |
5beb4930 | 538 | return -ENOMEM; |
287d97ac | 539 | importer->anon_vma = exporter->anon_vma; |
5beb4930 RR |
540 | } |
541 | } | |
542 | ||
1da177e4 LT |
543 | if (file) { |
544 | mapping = file->f_mapping; | |
682968e0 | 545 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
1da177e4 | 546 | root = &mapping->i_mmap; |
cbc91f71 | 547 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); |
682968e0 SD |
548 | |
549 | if (adjust_next) | |
cbc91f71 SD |
550 | uprobe_munmap(next, next->vm_start, |
551 | next->vm_end); | |
682968e0 SD |
552 | } |
553 | ||
3d48ae45 | 554 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 555 | if (insert) { |
1da177e4 | 556 | /* |
6b2dbba8 | 557 | * Put into interval tree now, so instantiated pages |
1da177e4 LT |
558 | * are visible to arm/parisc __flush_dcache_page |
559 | * throughout; but we cannot insert into address | |
560 | * space until vma start or end is updated. | |
561 | */ | |
562 | __vma_link_file(insert); | |
563 | } | |
564 | } | |
565 | ||
94fcc585 AA |
566 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
567 | ||
012f1800 RR |
568 | /* |
569 | * When changing only vma->vm_end, we don't really need anon_vma | |
570 | * lock. This is a fairly rare case by itself, but the anon_vma | |
571 | * lock may be shared between many sibling processes. Skipping | |
572 | * the lock for brk adjustments makes a difference sometimes. | |
573 | */ | |
5f70b962 | 574 | if (vma->anon_vma && (importer || start != vma->vm_start)) { |
012f1800 | 575 | anon_vma = vma->anon_vma; |
ca42b26a ML |
576 | VM_BUG_ON(adjust_next && next->anon_vma && |
577 | anon_vma != next->anon_vma); | |
578 | } else if (adjust_next && next->anon_vma) | |
579 | anon_vma = next->anon_vma; | |
580 | if (anon_vma) | |
012f1800 | 581 | anon_vma_lock(anon_vma); |
012f1800 | 582 | |
1da177e4 LT |
583 | if (root) { |
584 | flush_dcache_mmap_lock(mapping); | |
6b2dbba8 | 585 | vma_interval_tree_remove(vma, root); |
1da177e4 | 586 | if (adjust_next) |
6b2dbba8 | 587 | vma_interval_tree_remove(next, root); |
1da177e4 LT |
588 | } |
589 | ||
590 | vma->vm_start = start; | |
591 | vma->vm_end = end; | |
592 | vma->vm_pgoff = pgoff; | |
593 | if (adjust_next) { | |
594 | next->vm_start += adjust_next << PAGE_SHIFT; | |
595 | next->vm_pgoff += adjust_next; | |
596 | } | |
597 | ||
598 | if (root) { | |
599 | if (adjust_next) | |
6b2dbba8 ML |
600 | vma_interval_tree_insert(next, root); |
601 | vma_interval_tree_insert(vma, root); | |
1da177e4 LT |
602 | flush_dcache_mmap_unlock(mapping); |
603 | } | |
604 | ||
605 | if (remove_next) { | |
606 | /* | |
607 | * vma_merge has merged next into vma, and needs | |
608 | * us to remove next before dropping the locks. | |
609 | */ | |
610 | __vma_unlink(mm, next, vma); | |
611 | if (file) | |
612 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
613 | } else if (insert) { |
614 | /* | |
615 | * split_vma has split insert from vma, and needs | |
616 | * us to insert it before dropping the locks | |
617 | * (it may either follow vma or precede it). | |
618 | */ | |
619 | __insert_vm_struct(mm, insert); | |
620 | } | |
621 | ||
012f1800 RR |
622 | if (anon_vma) |
623 | anon_vma_unlock(anon_vma); | |
1da177e4 | 624 | if (mapping) |
3d48ae45 | 625 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 626 | |
2b144498 | 627 | if (root) { |
7b2d81d4 | 628 | uprobe_mmap(vma); |
2b144498 SD |
629 | |
630 | if (adjust_next) | |
7b2d81d4 | 631 | uprobe_mmap(next); |
2b144498 SD |
632 | } |
633 | ||
1da177e4 | 634 | if (remove_next) { |
925d1c40 | 635 | if (file) { |
cbc91f71 | 636 | uprobe_munmap(next, next->vm_start, next->vm_end); |
1da177e4 | 637 | fput(file); |
925d1c40 | 638 | } |
5beb4930 RR |
639 | if (next->anon_vma) |
640 | anon_vma_merge(vma, next); | |
1da177e4 | 641 | mm->map_count--; |
f0be3d32 | 642 | mpol_put(vma_policy(next)); |
1da177e4 LT |
643 | kmem_cache_free(vm_area_cachep, next); |
644 | /* | |
645 | * In mprotect's case 6 (see comments on vma_merge), | |
646 | * we must remove another next too. It would clutter | |
647 | * up the code too much to do both in one go. | |
648 | */ | |
649 | if (remove_next == 2) { | |
650 | next = vma->vm_next; | |
651 | goto again; | |
652 | } | |
653 | } | |
2b144498 | 654 | if (insert && file) |
7b2d81d4 | 655 | uprobe_mmap(insert); |
1da177e4 LT |
656 | |
657 | validate_mm(mm); | |
5beb4930 RR |
658 | |
659 | return 0; | |
1da177e4 LT |
660 | } |
661 | ||
662 | /* | |
663 | * If the vma has a ->close operation then the driver probably needs to release | |
664 | * per-vma resources, so we don't attempt to merge those. | |
665 | */ | |
1da177e4 LT |
666 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
667 | struct file *file, unsigned long vm_flags) | |
668 | { | |
0b173bc4 | 669 | if (vma->vm_flags ^ vm_flags) |
1da177e4 LT |
670 | return 0; |
671 | if (vma->vm_file != file) | |
672 | return 0; | |
673 | if (vma->vm_ops && vma->vm_ops->close) | |
674 | return 0; | |
675 | return 1; | |
676 | } | |
677 | ||
678 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
679 | struct anon_vma *anon_vma2, |
680 | struct vm_area_struct *vma) | |
1da177e4 | 681 | { |
965f55de SL |
682 | /* |
683 | * The list_is_singular() test is to avoid merging VMA cloned from | |
684 | * parents. This can improve scalability caused by anon_vma lock. | |
685 | */ | |
686 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
687 | list_is_singular(&vma->anon_vma_chain))) | |
688 | return 1; | |
689 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
690 | } |
691 | ||
692 | /* | |
693 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
694 | * in front of (at a lower virtual address and file offset than) the vma. | |
695 | * | |
696 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
697 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
698 | * | |
699 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
700 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
701 | * wrap, nor mmaps which cover the final page at index -1UL. | |
702 | */ | |
703 | static int | |
704 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
705 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
706 | { | |
707 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 708 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
709 | if (vma->vm_pgoff == vm_pgoff) |
710 | return 1; | |
711 | } | |
712 | return 0; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
717 | * beyond (at a higher virtual address and file offset than) the vma. | |
718 | * | |
719 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
720 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
721 | */ | |
722 | static int | |
723 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
724 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
725 | { | |
726 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 727 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
728 | pgoff_t vm_pglen; |
729 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
730 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
731 | return 1; | |
732 | } | |
733 | return 0; | |
734 | } | |
735 | ||
736 | /* | |
737 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
738 | * whether that can be merged with its predecessor or its successor. | |
739 | * Or both (it neatly fills a hole). | |
740 | * | |
741 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
742 | * certain not to be mapped by the time vma_merge is called; but when | |
743 | * called for mprotect, it is certain to be already mapped (either at | |
744 | * an offset within prev, or at the start of next), and the flags of | |
745 | * this area are about to be changed to vm_flags - and the no-change | |
746 | * case has already been eliminated. | |
747 | * | |
748 | * The following mprotect cases have to be considered, where AAAA is | |
749 | * the area passed down from mprotect_fixup, never extending beyond one | |
750 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
751 | * | |
752 | * AAAA AAAA AAAA AAAA | |
753 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
754 | * cannot merge might become might become might become | |
755 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
756 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
757 | * mremap move: PPPPNNNNNNNN 8 | |
758 | * AAAA | |
759 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
760 | * might become case 1 below case 2 below case 3 below | |
761 | * | |
762 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
763 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
764 | */ | |
765 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
766 | struct vm_area_struct *prev, unsigned long addr, | |
767 | unsigned long end, unsigned long vm_flags, | |
768 | struct anon_vma *anon_vma, struct file *file, | |
769 | pgoff_t pgoff, struct mempolicy *policy) | |
770 | { | |
771 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
772 | struct vm_area_struct *area, *next; | |
5beb4930 | 773 | int err; |
1da177e4 LT |
774 | |
775 | /* | |
776 | * We later require that vma->vm_flags == vm_flags, | |
777 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
778 | */ | |
779 | if (vm_flags & VM_SPECIAL) | |
780 | return NULL; | |
781 | ||
782 | if (prev) | |
783 | next = prev->vm_next; | |
784 | else | |
785 | next = mm->mmap; | |
786 | area = next; | |
787 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
788 | next = next->vm_next; | |
789 | ||
790 | /* | |
791 | * Can it merge with the predecessor? | |
792 | */ | |
793 | if (prev && prev->vm_end == addr && | |
794 | mpol_equal(vma_policy(prev), policy) && | |
795 | can_vma_merge_after(prev, vm_flags, | |
796 | anon_vma, file, pgoff)) { | |
797 | /* | |
798 | * OK, it can. Can we now merge in the successor as well? | |
799 | */ | |
800 | if (next && end == next->vm_start && | |
801 | mpol_equal(policy, vma_policy(next)) && | |
802 | can_vma_merge_before(next, vm_flags, | |
803 | anon_vma, file, pgoff+pglen) && | |
804 | is_mergeable_anon_vma(prev->anon_vma, | |
965f55de | 805 | next->anon_vma, NULL)) { |
1da177e4 | 806 | /* cases 1, 6 */ |
5beb4930 | 807 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
808 | next->vm_end, prev->vm_pgoff, NULL); |
809 | } else /* cases 2, 5, 7 */ | |
5beb4930 | 810 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 | 811 | end, prev->vm_pgoff, NULL); |
5beb4930 RR |
812 | if (err) |
813 | return NULL; | |
b15d00b6 | 814 | khugepaged_enter_vma_merge(prev); |
1da177e4 LT |
815 | return prev; |
816 | } | |
817 | ||
818 | /* | |
819 | * Can this new request be merged in front of next? | |
820 | */ | |
821 | if (next && end == next->vm_start && | |
822 | mpol_equal(policy, vma_policy(next)) && | |
823 | can_vma_merge_before(next, vm_flags, | |
824 | anon_vma, file, pgoff+pglen)) { | |
825 | if (prev && addr < prev->vm_end) /* case 4 */ | |
5beb4930 | 826 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
827 | addr, prev->vm_pgoff, NULL); |
828 | else /* cases 3, 8 */ | |
5beb4930 | 829 | err = vma_adjust(area, addr, next->vm_end, |
1da177e4 | 830 | next->vm_pgoff - pglen, NULL); |
5beb4930 RR |
831 | if (err) |
832 | return NULL; | |
b15d00b6 | 833 | khugepaged_enter_vma_merge(area); |
1da177e4 LT |
834 | return area; |
835 | } | |
836 | ||
837 | return NULL; | |
838 | } | |
839 | ||
d0e9fe17 LT |
840 | /* |
841 | * Rough compatbility check to quickly see if it's even worth looking | |
842 | * at sharing an anon_vma. | |
843 | * | |
844 | * They need to have the same vm_file, and the flags can only differ | |
845 | * in things that mprotect may change. | |
846 | * | |
847 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
848 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
849 | * there is a vm_ops->close() function, because that indicates that the | |
850 | * driver is doing some kind of reference counting. But that doesn't | |
851 | * really matter for the anon_vma sharing case. | |
852 | */ | |
853 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
854 | { | |
855 | return a->vm_end == b->vm_start && | |
856 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
857 | a->vm_file == b->vm_file && | |
858 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && | |
859 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); | |
860 | } | |
861 | ||
862 | /* | |
863 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
864 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
865 | * the same as 'old', the other will be the new one that is trying | |
866 | * to share the anon_vma. | |
867 | * | |
868 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
869 | * the anon_vma of 'old' is concurrently in the process of being set up | |
870 | * by another page fault trying to merge _that_. But that's ok: if it | |
871 | * is being set up, that automatically means that it will be a singleton | |
872 | * acceptable for merging, so we can do all of this optimistically. But | |
873 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. | |
874 | * | |
875 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
876 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
877 | * is to return an anon_vma that is "complex" due to having gone through | |
878 | * a fork). | |
879 | * | |
880 | * We also make sure that the two vma's are compatible (adjacent, | |
881 | * and with the same memory policies). That's all stable, even with just | |
882 | * a read lock on the mm_sem. | |
883 | */ | |
884 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
885 | { | |
886 | if (anon_vma_compatible(a, b)) { | |
887 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); | |
888 | ||
889 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
890 | return anon_vma; | |
891 | } | |
892 | return NULL; | |
893 | } | |
894 | ||
1da177e4 LT |
895 | /* |
896 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
897 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
898 | * to allocate a new anon_vma. It checks because a repetitive | |
899 | * sequence of mprotects and faults may otherwise lead to distinct | |
900 | * anon_vmas being allocated, preventing vma merge in subsequent | |
901 | * mprotect. | |
902 | */ | |
903 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
904 | { | |
d0e9fe17 | 905 | struct anon_vma *anon_vma; |
1da177e4 | 906 | struct vm_area_struct *near; |
1da177e4 LT |
907 | |
908 | near = vma->vm_next; | |
909 | if (!near) | |
910 | goto try_prev; | |
911 | ||
d0e9fe17 LT |
912 | anon_vma = reusable_anon_vma(near, vma, near); |
913 | if (anon_vma) | |
914 | return anon_vma; | |
1da177e4 | 915 | try_prev: |
9be34c9d | 916 | near = vma->vm_prev; |
1da177e4 LT |
917 | if (!near) |
918 | goto none; | |
919 | ||
d0e9fe17 LT |
920 | anon_vma = reusable_anon_vma(near, near, vma); |
921 | if (anon_vma) | |
922 | return anon_vma; | |
1da177e4 LT |
923 | none: |
924 | /* | |
925 | * There's no absolute need to look only at touching neighbours: | |
926 | * we could search further afield for "compatible" anon_vmas. | |
927 | * But it would probably just be a waste of time searching, | |
928 | * or lead to too many vmas hanging off the same anon_vma. | |
929 | * We're trying to allow mprotect remerging later on, | |
930 | * not trying to minimize memory used for anon_vmas. | |
931 | */ | |
932 | return NULL; | |
933 | } | |
934 | ||
935 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 936 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
937 | struct file *file, long pages) |
938 | { | |
939 | const unsigned long stack_flags | |
940 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
941 | ||
44de9d0c HS |
942 | mm->total_vm += pages; |
943 | ||
1da177e4 LT |
944 | if (file) { |
945 | mm->shared_vm += pages; | |
946 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
947 | mm->exec_vm += pages; | |
948 | } else if (flags & stack_flags) | |
949 | mm->stack_vm += pages; | |
1da177e4 LT |
950 | } |
951 | #endif /* CONFIG_PROC_FS */ | |
952 | ||
40401530 AV |
953 | /* |
954 | * If a hint addr is less than mmap_min_addr change hint to be as | |
955 | * low as possible but still greater than mmap_min_addr | |
956 | */ | |
957 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
958 | { | |
959 | hint &= PAGE_MASK; | |
960 | if (((void *)hint != NULL) && | |
961 | (hint < mmap_min_addr)) | |
962 | return PAGE_ALIGN(mmap_min_addr); | |
963 | return hint; | |
964 | } | |
965 | ||
1da177e4 | 966 | /* |
27f5de79 | 967 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
968 | */ |
969 | ||
e3fc629d | 970 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 LT |
971 | unsigned long len, unsigned long prot, |
972 | unsigned long flags, unsigned long pgoff) | |
973 | { | |
974 | struct mm_struct * mm = current->mm; | |
1da177e4 | 975 | struct inode *inode; |
ca16d140 | 976 | vm_flags_t vm_flags; |
1da177e4 | 977 | |
1da177e4 LT |
978 | /* |
979 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
980 | * | |
981 | * (the exception is when the underlying filesystem is noexec | |
982 | * mounted, in which case we dont add PROT_EXEC.) | |
983 | */ | |
984 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 985 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
986 | prot |= PROT_EXEC; |
987 | ||
988 | if (!len) | |
989 | return -EINVAL; | |
990 | ||
7cd94146 EP |
991 | if (!(flags & MAP_FIXED)) |
992 | addr = round_hint_to_min(addr); | |
993 | ||
1da177e4 LT |
994 | /* Careful about overflows.. */ |
995 | len = PAGE_ALIGN(len); | |
9206de95 | 996 | if (!len) |
1da177e4 LT |
997 | return -ENOMEM; |
998 | ||
999 | /* offset overflow? */ | |
1000 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
1001 | return -EOVERFLOW; | |
1002 | ||
1003 | /* Too many mappings? */ | |
1004 | if (mm->map_count > sysctl_max_map_count) | |
1005 | return -ENOMEM; | |
1006 | ||
1007 | /* Obtain the address to map to. we verify (or select) it and ensure | |
1008 | * that it represents a valid section of the address space. | |
1009 | */ | |
1010 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
1011 | if (addr & ~PAGE_MASK) | |
1012 | return addr; | |
1013 | ||
1014 | /* Do simple checking here so the lower-level routines won't have | |
1015 | * to. we assume access permissions have been handled by the open | |
1016 | * of the memory object, so we don't do any here. | |
1017 | */ | |
1018 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
1019 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
1020 | ||
cdf7b341 | 1021 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1022 | if (!can_do_mlock()) |
1023 | return -EPERM; | |
ba470de4 | 1024 | |
1da177e4 LT |
1025 | /* mlock MCL_FUTURE? */ |
1026 | if (vm_flags & VM_LOCKED) { | |
1027 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
1028 | locked = len >> PAGE_SHIFT; |
1029 | locked += mm->locked_vm; | |
59e99e5b | 1030 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 1031 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
1032 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1033 | return -EAGAIN; | |
1034 | } | |
1035 | ||
d3ac7f89 | 1036 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
1037 | |
1038 | if (file) { | |
1039 | switch (flags & MAP_TYPE) { | |
1040 | case MAP_SHARED: | |
1041 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1042 | return -EACCES; | |
1043 | ||
1044 | /* | |
1045 | * Make sure we don't allow writing to an append-only | |
1046 | * file.. | |
1047 | */ | |
1048 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1049 | return -EACCES; | |
1050 | ||
1051 | /* | |
1052 | * Make sure there are no mandatory locks on the file. | |
1053 | */ | |
1054 | if (locks_verify_locked(inode)) | |
1055 | return -EAGAIN; | |
1056 | ||
1057 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1058 | if (!(file->f_mode & FMODE_WRITE)) | |
1059 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1060 | ||
1061 | /* fall through */ | |
1062 | case MAP_PRIVATE: | |
1063 | if (!(file->f_mode & FMODE_READ)) | |
1064 | return -EACCES; | |
d3ac7f89 | 1065 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1066 | if (vm_flags & VM_EXEC) |
1067 | return -EPERM; | |
1068 | vm_flags &= ~VM_MAYEXEC; | |
1069 | } | |
80c5606c LT |
1070 | |
1071 | if (!file->f_op || !file->f_op->mmap) | |
1072 | return -ENODEV; | |
1da177e4 LT |
1073 | break; |
1074 | ||
1075 | default: | |
1076 | return -EINVAL; | |
1077 | } | |
1078 | } else { | |
1079 | switch (flags & MAP_TYPE) { | |
1080 | case MAP_SHARED: | |
ce363942 TH |
1081 | /* |
1082 | * Ignore pgoff. | |
1083 | */ | |
1084 | pgoff = 0; | |
1da177e4 LT |
1085 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1086 | break; | |
1087 | case MAP_PRIVATE: | |
1088 | /* | |
1089 | * Set pgoff according to addr for anon_vma. | |
1090 | */ | |
1091 | pgoff = addr >> PAGE_SHIFT; | |
1092 | break; | |
1093 | default: | |
1094 | return -EINVAL; | |
1095 | } | |
1096 | } | |
1097 | ||
5a6fe125 | 1098 | return mmap_region(file, addr, len, flags, vm_flags, pgoff); |
0165ab44 | 1099 | } |
6be5ceb0 | 1100 | |
66f0dc48 HD |
1101 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1102 | unsigned long, prot, unsigned long, flags, | |
1103 | unsigned long, fd, unsigned long, pgoff) | |
1104 | { | |
1105 | struct file *file = NULL; | |
1106 | unsigned long retval = -EBADF; | |
1107 | ||
1108 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1109 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1110 | if (unlikely(flags & MAP_HUGETLB)) |
1111 | return -EINVAL; | |
1112 | file = fget(fd); | |
1113 | if (!file) | |
1114 | goto out; | |
1115 | } else if (flags & MAP_HUGETLB) { | |
1116 | struct user_struct *user = NULL; | |
1117 | /* | |
1118 | * VM_NORESERVE is used because the reservations will be | |
1119 | * taken when vm_ops->mmap() is called | |
1120 | * A dummy user value is used because we are not locking | |
1121 | * memory so no accounting is necessary | |
1122 | */ | |
40716e29 ST |
1123 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len, |
1124 | VM_NORESERVE, &user, | |
1125 | HUGETLB_ANONHUGE_INODE); | |
66f0dc48 HD |
1126 | if (IS_ERR(file)) |
1127 | return PTR_ERR(file); | |
1128 | } | |
1129 | ||
1130 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1131 | ||
eb36c587 | 1132 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
66f0dc48 HD |
1133 | if (file) |
1134 | fput(file); | |
1135 | out: | |
1136 | return retval; | |
1137 | } | |
1138 | ||
a4679373 CH |
1139 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1140 | struct mmap_arg_struct { | |
1141 | unsigned long addr; | |
1142 | unsigned long len; | |
1143 | unsigned long prot; | |
1144 | unsigned long flags; | |
1145 | unsigned long fd; | |
1146 | unsigned long offset; | |
1147 | }; | |
1148 | ||
1149 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1150 | { | |
1151 | struct mmap_arg_struct a; | |
1152 | ||
1153 | if (copy_from_user(&a, arg, sizeof(a))) | |
1154 | return -EFAULT; | |
1155 | if (a.offset & ~PAGE_MASK) | |
1156 | return -EINVAL; | |
1157 | ||
1158 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1159 | a.offset >> PAGE_SHIFT); | |
1160 | } | |
1161 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1162 | ||
4e950f6f AD |
1163 | /* |
1164 | * Some shared mappigns will want the pages marked read-only | |
1165 | * to track write events. If so, we'll downgrade vm_page_prot | |
1166 | * to the private version (using protection_map[] without the | |
1167 | * VM_SHARED bit). | |
1168 | */ | |
1169 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1170 | { | |
ca16d140 | 1171 | vm_flags_t vm_flags = vma->vm_flags; |
4e950f6f AD |
1172 | |
1173 | /* If it was private or non-writable, the write bit is already clear */ | |
1174 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1175 | return 0; | |
1176 | ||
1177 | /* The backer wishes to know when pages are first written to? */ | |
1178 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1179 | return 1; | |
1180 | ||
1181 | /* The open routine did something to the protections already? */ | |
1182 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1183 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1184 | return 0; |
1185 | ||
1186 | /* Specialty mapping? */ | |
4b6e1e37 | 1187 | if (vm_flags & VM_PFNMAP) |
4e950f6f AD |
1188 | return 0; |
1189 | ||
1190 | /* Can the mapping track the dirty pages? */ | |
1191 | return vma->vm_file && vma->vm_file->f_mapping && | |
1192 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1193 | } | |
1194 | ||
fc8744ad LT |
1195 | /* |
1196 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1197 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1198 | */ |
ca16d140 | 1199 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1200 | { |
5a6fe125 MG |
1201 | /* |
1202 | * hugetlb has its own accounting separate from the core VM | |
1203 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1204 | */ | |
1205 | if (file && is_file_hugepages(file)) | |
1206 | return 0; | |
1207 | ||
fc8744ad LT |
1208 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1209 | } | |
1210 | ||
0165ab44 MS |
1211 | unsigned long mmap_region(struct file *file, unsigned long addr, |
1212 | unsigned long len, unsigned long flags, | |
ca16d140 | 1213 | vm_flags_t vm_flags, unsigned long pgoff) |
0165ab44 MS |
1214 | { |
1215 | struct mm_struct *mm = current->mm; | |
1216 | struct vm_area_struct *vma, *prev; | |
1217 | int correct_wcount = 0; | |
1218 | int error; | |
1219 | struct rb_node **rb_link, *rb_parent; | |
1220 | unsigned long charged = 0; | |
1221 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; | |
1222 | ||
1da177e4 LT |
1223 | /* Clear old maps */ |
1224 | error = -ENOMEM; | |
1225 | munmap_back: | |
6597d783 | 1226 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
1227 | if (do_munmap(mm, addr, len)) |
1228 | return -ENOMEM; | |
1229 | goto munmap_back; | |
1230 | } | |
1231 | ||
1232 | /* Check against address space limit. */ | |
119f657c | 1233 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1234 | return -ENOMEM; |
1235 | ||
fc8744ad LT |
1236 | /* |
1237 | * Set 'VM_NORESERVE' if we should not account for the | |
5a6fe125 | 1238 | * memory use of this mapping. |
fc8744ad | 1239 | */ |
5a6fe125 MG |
1240 | if ((flags & MAP_NORESERVE)) { |
1241 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1242 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1243 | vm_flags |= VM_NORESERVE; | |
1244 | ||
1245 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1246 | if (file && is_file_hugepages(file)) | |
1247 | vm_flags |= VM_NORESERVE; | |
1248 | } | |
cdfd4325 | 1249 | |
fc8744ad LT |
1250 | /* |
1251 | * Private writable mapping: check memory availability | |
1252 | */ | |
5a6fe125 | 1253 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1254 | charged = len >> PAGE_SHIFT; |
191c5424 | 1255 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1256 | return -ENOMEM; |
1257 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1258 | } |
1259 | ||
1260 | /* | |
de33c8db | 1261 | * Can we just expand an old mapping? |
1da177e4 | 1262 | */ |
de33c8db LT |
1263 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1264 | if (vma) | |
1265 | goto out; | |
1da177e4 LT |
1266 | |
1267 | /* | |
1268 | * Determine the object being mapped and call the appropriate | |
1269 | * specific mapper. the address has already been validated, but | |
1270 | * not unmapped, but the maps are removed from the list. | |
1271 | */ | |
c5e3b83e | 1272 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1273 | if (!vma) { |
1274 | error = -ENOMEM; | |
1275 | goto unacct_error; | |
1276 | } | |
1da177e4 LT |
1277 | |
1278 | vma->vm_mm = mm; | |
1279 | vma->vm_start = addr; | |
1280 | vma->vm_end = addr + len; | |
1281 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1282 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1283 | vma->vm_pgoff = pgoff; |
5beb4930 | 1284 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 | 1285 | |
ce8fea7a HD |
1286 | error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */ |
1287 | ||
1da177e4 | 1288 | if (file) { |
1da177e4 LT |
1289 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1290 | goto free_vma; | |
1291 | if (vm_flags & VM_DENYWRITE) { | |
1292 | error = deny_write_access(file); | |
1293 | if (error) | |
1294 | goto free_vma; | |
1295 | correct_wcount = 1; | |
1296 | } | |
cb0942b8 | 1297 | vma->vm_file = get_file(file); |
1da177e4 LT |
1298 | error = file->f_op->mmap(file, vma); |
1299 | if (error) | |
1300 | goto unmap_and_free_vma; | |
f8dbf0a7 HS |
1301 | |
1302 | /* Can addr have changed?? | |
1303 | * | |
1304 | * Answer: Yes, several device drivers can do it in their | |
1305 | * f_op->mmap method. -DaveM | |
1306 | */ | |
1307 | addr = vma->vm_start; | |
1308 | pgoff = vma->vm_pgoff; | |
1309 | vm_flags = vma->vm_flags; | |
1da177e4 | 1310 | } else if (vm_flags & VM_SHARED) { |
835ee797 AV |
1311 | if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))) |
1312 | goto free_vma; | |
1da177e4 LT |
1313 | error = shmem_zero_setup(vma); |
1314 | if (error) | |
1315 | goto free_vma; | |
1316 | } | |
1317 | ||
c9d0bf24 MD |
1318 | if (vma_wants_writenotify(vma)) { |
1319 | pgprot_t pprot = vma->vm_page_prot; | |
1320 | ||
1321 | /* Can vma->vm_page_prot have changed?? | |
1322 | * | |
1323 | * Answer: Yes, drivers may have changed it in their | |
1324 | * f_op->mmap method. | |
1325 | * | |
1326 | * Ensures that vmas marked as uncached stay that way. | |
1327 | */ | |
1ddd439e | 1328 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
c9d0bf24 MD |
1329 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
1330 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
1331 | } | |
d08b3851 | 1332 | |
de33c8db LT |
1333 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1334 | file = vma->vm_file; | |
4d3d5b41 ON |
1335 | |
1336 | /* Once vma denies write, undo our temporary denial count */ | |
1337 | if (correct_wcount) | |
1338 | atomic_inc(&inode->i_writecount); | |
1339 | out: | |
cdd6c482 | 1340 | perf_event_mmap(vma); |
0a4a9391 | 1341 | |
ab50b8ed | 1342 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1343 | if (vm_flags & VM_LOCKED) { |
06f9d8c2 KM |
1344 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
1345 | mm->locked_vm += (len >> PAGE_SHIFT); | |
ba470de4 | 1346 | } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
54cb8821 | 1347 | make_pages_present(addr, addr + len); |
2b144498 | 1348 | |
c7a3a88c ON |
1349 | if (file) |
1350 | uprobe_mmap(vma); | |
2b144498 | 1351 | |
1da177e4 LT |
1352 | return addr; |
1353 | ||
1354 | unmap_and_free_vma: | |
1355 | if (correct_wcount) | |
1356 | atomic_inc(&inode->i_writecount); | |
1357 | vma->vm_file = NULL; | |
1358 | fput(file); | |
1359 | ||
1360 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1361 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1362 | charged = 0; | |
1da177e4 LT |
1363 | free_vma: |
1364 | kmem_cache_free(vm_area_cachep, vma); | |
1365 | unacct_error: | |
1366 | if (charged) | |
1367 | vm_unacct_memory(charged); | |
1368 | return error; | |
1369 | } | |
1370 | ||
1da177e4 LT |
1371 | /* Get an address range which is currently unmapped. |
1372 | * For shmat() with addr=0. | |
1373 | * | |
1374 | * Ugly calling convention alert: | |
1375 | * Return value with the low bits set means error value, | |
1376 | * ie | |
1377 | * if (ret & ~PAGE_MASK) | |
1378 | * error = ret; | |
1379 | * | |
1380 | * This function "knows" that -ENOMEM has the bits set. | |
1381 | */ | |
1382 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1383 | unsigned long | |
1384 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1385 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1386 | { | |
1387 | struct mm_struct *mm = current->mm; | |
1388 | struct vm_area_struct *vma; | |
1389 | unsigned long start_addr; | |
1390 | ||
1391 | if (len > TASK_SIZE) | |
1392 | return -ENOMEM; | |
1393 | ||
06abdfb4 BH |
1394 | if (flags & MAP_FIXED) |
1395 | return addr; | |
1396 | ||
1da177e4 LT |
1397 | if (addr) { |
1398 | addr = PAGE_ALIGN(addr); | |
1399 | vma = find_vma(mm, addr); | |
1400 | if (TASK_SIZE - len >= addr && | |
1401 | (!vma || addr + len <= vma->vm_start)) | |
1402 | return addr; | |
1403 | } | |
1363c3cd WW |
1404 | if (len > mm->cached_hole_size) { |
1405 | start_addr = addr = mm->free_area_cache; | |
1406 | } else { | |
1407 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1408 | mm->cached_hole_size = 0; | |
1409 | } | |
1da177e4 LT |
1410 | |
1411 | full_search: | |
1412 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1413 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1414 | if (TASK_SIZE - len < addr) { | |
1415 | /* | |
1416 | * Start a new search - just in case we missed | |
1417 | * some holes. | |
1418 | */ | |
1419 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1420 | addr = TASK_UNMAPPED_BASE; |
1421 | start_addr = addr; | |
1422 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1423 | goto full_search; |
1424 | } | |
1425 | return -ENOMEM; | |
1426 | } | |
1427 | if (!vma || addr + len <= vma->vm_start) { | |
1428 | /* | |
1429 | * Remember the place where we stopped the search: | |
1430 | */ | |
1431 | mm->free_area_cache = addr + len; | |
1432 | return addr; | |
1433 | } | |
1363c3cd WW |
1434 | if (addr + mm->cached_hole_size < vma->vm_start) |
1435 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1436 | addr = vma->vm_end; |
1437 | } | |
1438 | } | |
1439 | #endif | |
1440 | ||
1363c3cd | 1441 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1442 | { |
1443 | /* | |
1444 | * Is this a new hole at the lowest possible address? | |
1445 | */ | |
f44d2198 | 1446 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) |
1363c3cd | 1447 | mm->free_area_cache = addr; |
1da177e4 LT |
1448 | } |
1449 | ||
1450 | /* | |
1451 | * This mmap-allocator allocates new areas top-down from below the | |
1452 | * stack's low limit (the base): | |
1453 | */ | |
1454 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1455 | unsigned long | |
1456 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1457 | const unsigned long len, const unsigned long pgoff, | |
1458 | const unsigned long flags) | |
1459 | { | |
1460 | struct vm_area_struct *vma; | |
1461 | struct mm_struct *mm = current->mm; | |
b716ad95 | 1462 | unsigned long addr = addr0, start_addr; |
1da177e4 LT |
1463 | |
1464 | /* requested length too big for entire address space */ | |
1465 | if (len > TASK_SIZE) | |
1466 | return -ENOMEM; | |
1467 | ||
06abdfb4 BH |
1468 | if (flags & MAP_FIXED) |
1469 | return addr; | |
1470 | ||
1da177e4 LT |
1471 | /* requesting a specific address */ |
1472 | if (addr) { | |
1473 | addr = PAGE_ALIGN(addr); | |
1474 | vma = find_vma(mm, addr); | |
1475 | if (TASK_SIZE - len >= addr && | |
1476 | (!vma || addr + len <= vma->vm_start)) | |
1477 | return addr; | |
1478 | } | |
1479 | ||
1363c3cd WW |
1480 | /* check if free_area_cache is useful for us */ |
1481 | if (len <= mm->cached_hole_size) { | |
1482 | mm->cached_hole_size = 0; | |
1483 | mm->free_area_cache = mm->mmap_base; | |
1484 | } | |
1485 | ||
b716ad95 | 1486 | try_again: |
1da177e4 | 1487 | /* either no address requested or can't fit in requested address hole */ |
b716ad95 | 1488 | start_addr = addr = mm->free_area_cache; |
73219d17 | 1489 | |
b716ad95 XG |
1490 | if (addr < len) |
1491 | goto fail; | |
1da177e4 | 1492 | |
b716ad95 | 1493 | addr -= len; |
1da177e4 LT |
1494 | do { |
1495 | /* | |
1496 | * Lookup failure means no vma is above this address, | |
1497 | * else if new region fits below vma->vm_start, | |
1498 | * return with success: | |
1499 | */ | |
1500 | vma = find_vma(mm, addr); | |
1501 | if (!vma || addr+len <= vma->vm_start) | |
1502 | /* remember the address as a hint for next time */ | |
1503 | return (mm->free_area_cache = addr); | |
1504 | ||
1363c3cd WW |
1505 | /* remember the largest hole we saw so far */ |
1506 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1507 | mm->cached_hole_size = vma->vm_start - addr; | |
1508 | ||
1da177e4 LT |
1509 | /* try just below the current vma->vm_start */ |
1510 | addr = vma->vm_start-len; | |
49a43876 | 1511 | } while (len < vma->vm_start); |
1da177e4 | 1512 | |
b716ad95 XG |
1513 | fail: |
1514 | /* | |
1515 | * if hint left us with no space for the requested | |
1516 | * mapping then try again: | |
1517 | * | |
1518 | * Note: this is different with the case of bottomup | |
1519 | * which does the fully line-search, but we use find_vma | |
1520 | * here that causes some holes skipped. | |
1521 | */ | |
1522 | if (start_addr != mm->mmap_base) { | |
1523 | mm->free_area_cache = mm->mmap_base; | |
1524 | mm->cached_hole_size = 0; | |
1525 | goto try_again; | |
1526 | } | |
1527 | ||
1da177e4 LT |
1528 | /* |
1529 | * A failed mmap() very likely causes application failure, | |
1530 | * so fall back to the bottom-up function here. This scenario | |
1531 | * can happen with large stack limits and large mmap() | |
1532 | * allocations. | |
1533 | */ | |
1363c3cd WW |
1534 | mm->cached_hole_size = ~0UL; |
1535 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1536 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1537 | /* | |
1538 | * Restore the topdown base: | |
1539 | */ | |
1540 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1541 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1542 | |
1543 | return addr; | |
1544 | } | |
1545 | #endif | |
1546 | ||
1363c3cd | 1547 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1548 | { |
1549 | /* | |
1550 | * Is this a new hole at the highest possible address? | |
1551 | */ | |
1363c3cd WW |
1552 | if (addr > mm->free_area_cache) |
1553 | mm->free_area_cache = addr; | |
1da177e4 LT |
1554 | |
1555 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1556 | if (mm->free_area_cache > mm->mmap_base) |
1557 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1558 | } |
1559 | ||
1560 | unsigned long | |
1561 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1562 | unsigned long pgoff, unsigned long flags) | |
1563 | { | |
06abdfb4 BH |
1564 | unsigned long (*get_area)(struct file *, unsigned long, |
1565 | unsigned long, unsigned long, unsigned long); | |
1566 | ||
9206de95 AV |
1567 | unsigned long error = arch_mmap_check(addr, len, flags); |
1568 | if (error) | |
1569 | return error; | |
1570 | ||
1571 | /* Careful about overflows.. */ | |
1572 | if (len > TASK_SIZE) | |
1573 | return -ENOMEM; | |
1574 | ||
06abdfb4 BH |
1575 | get_area = current->mm->get_unmapped_area; |
1576 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1577 | get_area = file->f_op->get_unmapped_area; | |
1578 | addr = get_area(file, addr, len, pgoff, flags); | |
1579 | if (IS_ERR_VALUE(addr)) | |
1580 | return addr; | |
1da177e4 | 1581 | |
07ab67c8 LT |
1582 | if (addr > TASK_SIZE - len) |
1583 | return -ENOMEM; | |
1584 | if (addr & ~PAGE_MASK) | |
1585 | return -EINVAL; | |
06abdfb4 | 1586 | |
9ac4ed4b AV |
1587 | addr = arch_rebalance_pgtables(addr, len); |
1588 | error = security_mmap_addr(addr); | |
1589 | return error ? error : addr; | |
1da177e4 LT |
1590 | } |
1591 | ||
1592 | EXPORT_SYMBOL(get_unmapped_area); | |
1593 | ||
1594 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1595 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1596 | { |
1597 | struct vm_area_struct *vma = NULL; | |
1598 | ||
841e31e5 RM |
1599 | if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */ |
1600 | return NULL; | |
1601 | ||
1602 | /* Check the cache first. */ | |
1603 | /* (Cache hit rate is typically around 35%.) */ | |
1604 | vma = mm->mmap_cache; | |
1605 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1606 | struct rb_node *rb_node; | |
1607 | ||
1608 | rb_node = mm->mm_rb.rb_node; | |
1609 | vma = NULL; | |
1610 | ||
1611 | while (rb_node) { | |
1612 | struct vm_area_struct *vma_tmp; | |
1613 | ||
1614 | vma_tmp = rb_entry(rb_node, | |
1615 | struct vm_area_struct, vm_rb); | |
1616 | ||
1617 | if (vma_tmp->vm_end > addr) { | |
1618 | vma = vma_tmp; | |
1619 | if (vma_tmp->vm_start <= addr) | |
1620 | break; | |
1621 | rb_node = rb_node->rb_left; | |
1622 | } else | |
1623 | rb_node = rb_node->rb_right; | |
1da177e4 | 1624 | } |
841e31e5 RM |
1625 | if (vma) |
1626 | mm->mmap_cache = vma; | |
1da177e4 LT |
1627 | } |
1628 | return vma; | |
1629 | } | |
1630 | ||
1631 | EXPORT_SYMBOL(find_vma); | |
1632 | ||
6bd4837d KM |
1633 | /* |
1634 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 1635 | */ |
1da177e4 LT |
1636 | struct vm_area_struct * |
1637 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1638 | struct vm_area_struct **pprev) | |
1639 | { | |
6bd4837d | 1640 | struct vm_area_struct *vma; |
1da177e4 | 1641 | |
6bd4837d | 1642 | vma = find_vma(mm, addr); |
83cd904d MP |
1643 | if (vma) { |
1644 | *pprev = vma->vm_prev; | |
1645 | } else { | |
1646 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
1647 | *pprev = NULL; | |
1648 | while (rb_node) { | |
1649 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1650 | rb_node = rb_node->rb_right; | |
1651 | } | |
1652 | } | |
6bd4837d | 1653 | return vma; |
1da177e4 LT |
1654 | } |
1655 | ||
1656 | /* | |
1657 | * Verify that the stack growth is acceptable and | |
1658 | * update accounting. This is shared with both the | |
1659 | * grow-up and grow-down cases. | |
1660 | */ | |
48aae425 | 1661 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
1662 | { |
1663 | struct mm_struct *mm = vma->vm_mm; | |
1664 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1665 | unsigned long new_start; |
1da177e4 LT |
1666 | |
1667 | /* address space limit tests */ | |
119f657c | 1668 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1669 | return -ENOMEM; |
1670 | ||
1671 | /* Stack limit test */ | |
59e99e5b | 1672 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
1da177e4 LT |
1673 | return -ENOMEM; |
1674 | ||
1675 | /* mlock limit tests */ | |
1676 | if (vma->vm_flags & VM_LOCKED) { | |
1677 | unsigned long locked; | |
1678 | unsigned long limit; | |
1679 | locked = mm->locked_vm + grow; | |
59e99e5b JS |
1680 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
1681 | limit >>= PAGE_SHIFT; | |
1da177e4 LT |
1682 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
1683 | return -ENOMEM; | |
1684 | } | |
1685 | ||
0d59a01b AL |
1686 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1687 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1688 | vma->vm_end - size; | |
1689 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1690 | return -EFAULT; | |
1691 | ||
1da177e4 LT |
1692 | /* |
1693 | * Overcommit.. This must be the final test, as it will | |
1694 | * update security statistics. | |
1695 | */ | |
05fa199d | 1696 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
1697 | return -ENOMEM; |
1698 | ||
1699 | /* Ok, everything looks good - let it rip */ | |
1da177e4 LT |
1700 | if (vma->vm_flags & VM_LOCKED) |
1701 | mm->locked_vm += grow; | |
ab50b8ed | 1702 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1703 | return 0; |
1704 | } | |
1705 | ||
46dea3d0 | 1706 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1707 | /* |
46dea3d0 HD |
1708 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1709 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1710 | */ |
46dea3d0 | 1711 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 LT |
1712 | { |
1713 | int error; | |
1714 | ||
1715 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1716 | return -EFAULT; | |
1717 | ||
1718 | /* | |
1719 | * We must make sure the anon_vma is allocated | |
1720 | * so that the anon_vma locking is not a noop. | |
1721 | */ | |
1722 | if (unlikely(anon_vma_prepare(vma))) | |
1723 | return -ENOMEM; | |
bb4a340e | 1724 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1725 | |
1726 | /* | |
1727 | * vma->vm_start/vm_end cannot change under us because the caller | |
1728 | * is required to hold the mmap_sem in read mode. We need the | |
1729 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 1730 | * Also guard against wrapping around to address 0. |
1da177e4 | 1731 | */ |
06b32f3a HD |
1732 | if (address < PAGE_ALIGN(address+4)) |
1733 | address = PAGE_ALIGN(address+4); | |
1734 | else { | |
bb4a340e | 1735 | vma_unlock_anon_vma(vma); |
06b32f3a HD |
1736 | return -ENOMEM; |
1737 | } | |
1da177e4 LT |
1738 | error = 0; |
1739 | ||
1740 | /* Somebody else might have raced and expanded it already */ | |
1741 | if (address > vma->vm_end) { | |
1742 | unsigned long size, grow; | |
1743 | ||
1744 | size = address - vma->vm_start; | |
1745 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1746 | ||
42c36f63 HD |
1747 | error = -ENOMEM; |
1748 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
1749 | error = acct_stack_growth(vma, size, grow); | |
1750 | if (!error) { | |
1751 | vma->vm_end = address; | |
1752 | perf_event_mmap(vma); | |
1753 | } | |
3af9e859 | 1754 | } |
1da177e4 | 1755 | } |
bb4a340e | 1756 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1757 | khugepaged_enter_vma_merge(vma); |
1da177e4 LT |
1758 | return error; |
1759 | } | |
46dea3d0 HD |
1760 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1761 | ||
1da177e4 LT |
1762 | /* |
1763 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1764 | */ | |
d05f3169 | 1765 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 1766 | unsigned long address) |
1da177e4 LT |
1767 | { |
1768 | int error; | |
1769 | ||
1770 | /* | |
1771 | * We must make sure the anon_vma is allocated | |
1772 | * so that the anon_vma locking is not a noop. | |
1773 | */ | |
1774 | if (unlikely(anon_vma_prepare(vma))) | |
1775 | return -ENOMEM; | |
8869477a EP |
1776 | |
1777 | address &= PAGE_MASK; | |
e5467859 | 1778 | error = security_mmap_addr(address); |
8869477a EP |
1779 | if (error) |
1780 | return error; | |
1781 | ||
bb4a340e | 1782 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1783 | |
1784 | /* | |
1785 | * vma->vm_start/vm_end cannot change under us because the caller | |
1786 | * is required to hold the mmap_sem in read mode. We need the | |
1787 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1788 | */ | |
1da177e4 LT |
1789 | |
1790 | /* Somebody else might have raced and expanded it already */ | |
1791 | if (address < vma->vm_start) { | |
1792 | unsigned long size, grow; | |
1793 | ||
1794 | size = vma->vm_end - address; | |
1795 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1796 | ||
a626ca6a LT |
1797 | error = -ENOMEM; |
1798 | if (grow <= vma->vm_pgoff) { | |
1799 | error = acct_stack_growth(vma, size, grow); | |
1800 | if (!error) { | |
1801 | vma->vm_start = address; | |
1802 | vma->vm_pgoff -= grow; | |
1803 | perf_event_mmap(vma); | |
1804 | } | |
1da177e4 LT |
1805 | } |
1806 | } | |
bb4a340e | 1807 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1808 | khugepaged_enter_vma_merge(vma); |
1da177e4 LT |
1809 | return error; |
1810 | } | |
1811 | ||
b6a2fea3 OW |
1812 | #ifdef CONFIG_STACK_GROWSUP |
1813 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1814 | { | |
1815 | return expand_upwards(vma, address); | |
1816 | } | |
1817 | ||
1818 | struct vm_area_struct * | |
1819 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1820 | { | |
1821 | struct vm_area_struct *vma, *prev; | |
1822 | ||
1823 | addr &= PAGE_MASK; | |
1824 | vma = find_vma_prev(mm, addr, &prev); | |
1825 | if (vma && (vma->vm_start <= addr)) | |
1826 | return vma; | |
1c127185 | 1827 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 1828 | return NULL; |
ba470de4 | 1829 | if (prev->vm_flags & VM_LOCKED) { |
c58267c3 | 1830 | mlock_vma_pages_range(prev, addr, prev->vm_end); |
ba470de4 | 1831 | } |
b6a2fea3 OW |
1832 | return prev; |
1833 | } | |
1834 | #else | |
1835 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1836 | { | |
1837 | return expand_downwards(vma, address); | |
1838 | } | |
1839 | ||
1da177e4 LT |
1840 | struct vm_area_struct * |
1841 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1842 | { | |
1843 | struct vm_area_struct * vma; | |
1844 | unsigned long start; | |
1845 | ||
1846 | addr &= PAGE_MASK; | |
1847 | vma = find_vma(mm,addr); | |
1848 | if (!vma) | |
1849 | return NULL; | |
1850 | if (vma->vm_start <= addr) | |
1851 | return vma; | |
1852 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1853 | return NULL; | |
1854 | start = vma->vm_start; | |
1855 | if (expand_stack(vma, addr)) | |
1856 | return NULL; | |
ba470de4 | 1857 | if (vma->vm_flags & VM_LOCKED) { |
c58267c3 | 1858 | mlock_vma_pages_range(vma, addr, start); |
ba470de4 | 1859 | } |
1da177e4 LT |
1860 | return vma; |
1861 | } | |
1862 | #endif | |
1863 | ||
1da177e4 | 1864 | /* |
2c0b3814 | 1865 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1866 | * so release them, and do the vma updates. |
2c0b3814 HD |
1867 | * |
1868 | * Called with the mm semaphore held. | |
1da177e4 | 1869 | */ |
2c0b3814 | 1870 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1871 | { |
4f74d2c8 LT |
1872 | unsigned long nr_accounted = 0; |
1873 | ||
365e9c87 HD |
1874 | /* Update high watermark before we lower total_vm */ |
1875 | update_hiwater_vm(mm); | |
1da177e4 | 1876 | do { |
2c0b3814 HD |
1877 | long nrpages = vma_pages(vma); |
1878 | ||
4f74d2c8 LT |
1879 | if (vma->vm_flags & VM_ACCOUNT) |
1880 | nr_accounted += nrpages; | |
2c0b3814 | 1881 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 1882 | vma = remove_vma(vma); |
146425a3 | 1883 | } while (vma); |
4f74d2c8 | 1884 | vm_unacct_memory(nr_accounted); |
1da177e4 LT |
1885 | validate_mm(mm); |
1886 | } | |
1887 | ||
1888 | /* | |
1889 | * Get rid of page table information in the indicated region. | |
1890 | * | |
f10df686 | 1891 | * Called with the mm semaphore held. |
1da177e4 LT |
1892 | */ |
1893 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1894 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1895 | unsigned long start, unsigned long end) | |
1da177e4 | 1896 | { |
e0da382c | 1897 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
d16dfc55 | 1898 | struct mmu_gather tlb; |
1da177e4 LT |
1899 | |
1900 | lru_add_drain(); | |
d16dfc55 | 1901 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1902 | update_hiwater_rss(mm); |
4f74d2c8 | 1903 | unmap_vmas(&tlb, vma, start, end); |
d16dfc55 PZ |
1904 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
1905 | next ? next->vm_start : 0); | |
1906 | tlb_finish_mmu(&tlb, start, end); | |
1da177e4 LT |
1907 | } |
1908 | ||
1909 | /* | |
1910 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1911 | * vma list as we go.. | |
1912 | */ | |
1913 | static void | |
1914 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1915 | struct vm_area_struct *prev, unsigned long end) | |
1916 | { | |
1917 | struct vm_area_struct **insertion_point; | |
1918 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1919 | unsigned long addr; |
1da177e4 LT |
1920 | |
1921 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 1922 | vma->vm_prev = NULL; |
1da177e4 LT |
1923 | do { |
1924 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1925 | mm->map_count--; | |
1926 | tail_vma = vma; | |
1927 | vma = vma->vm_next; | |
1928 | } while (vma && vma->vm_start < end); | |
1929 | *insertion_point = vma; | |
297c5eee LT |
1930 | if (vma) |
1931 | vma->vm_prev = prev; | |
1da177e4 | 1932 | tail_vma->vm_next = NULL; |
1363c3cd WW |
1933 | if (mm->unmap_area == arch_unmap_area) |
1934 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1935 | else | |
1936 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1937 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1938 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1939 | } | |
1940 | ||
1941 | /* | |
659ace58 KM |
1942 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
1943 | * munmap path where it doesn't make sense to fail. | |
1da177e4 | 1944 | */ |
659ace58 | 1945 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1da177e4 LT |
1946 | unsigned long addr, int new_below) |
1947 | { | |
1948 | struct mempolicy *pol; | |
1949 | struct vm_area_struct *new; | |
5beb4930 | 1950 | int err = -ENOMEM; |
1da177e4 | 1951 | |
a5516438 AK |
1952 | if (is_vm_hugetlb_page(vma) && (addr & |
1953 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
1954 | return -EINVAL; |
1955 | ||
e94b1766 | 1956 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 1957 | if (!new) |
5beb4930 | 1958 | goto out_err; |
1da177e4 LT |
1959 | |
1960 | /* most fields are the same, copy all, and then fixup */ | |
1961 | *new = *vma; | |
1962 | ||
5beb4930 RR |
1963 | INIT_LIST_HEAD(&new->anon_vma_chain); |
1964 | ||
1da177e4 LT |
1965 | if (new_below) |
1966 | new->vm_end = addr; | |
1967 | else { | |
1968 | new->vm_start = addr; | |
1969 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
1970 | } | |
1971 | ||
846a16bf | 1972 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 | 1973 | if (IS_ERR(pol)) { |
5beb4930 RR |
1974 | err = PTR_ERR(pol); |
1975 | goto out_free_vma; | |
1da177e4 LT |
1976 | } |
1977 | vma_set_policy(new, pol); | |
1978 | ||
5beb4930 RR |
1979 | if (anon_vma_clone(new, vma)) |
1980 | goto out_free_mpol; | |
1981 | ||
e9714acf | 1982 | if (new->vm_file) |
1da177e4 LT |
1983 | get_file(new->vm_file); |
1984 | ||
1985 | if (new->vm_ops && new->vm_ops->open) | |
1986 | new->vm_ops->open(new); | |
1987 | ||
1988 | if (new_below) | |
5beb4930 | 1989 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
1990 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
1991 | else | |
5beb4930 | 1992 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 1993 | |
5beb4930 RR |
1994 | /* Success. */ |
1995 | if (!err) | |
1996 | return 0; | |
1997 | ||
1998 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
1999 | if (new->vm_ops && new->vm_ops->close) |
2000 | new->vm_ops->close(new); | |
e9714acf | 2001 | if (new->vm_file) |
5beb4930 | 2002 | fput(new->vm_file); |
2aeadc30 | 2003 | unlink_anon_vmas(new); |
5beb4930 RR |
2004 | out_free_mpol: |
2005 | mpol_put(pol); | |
2006 | out_free_vma: | |
2007 | kmem_cache_free(vm_area_cachep, new); | |
2008 | out_err: | |
2009 | return err; | |
1da177e4 LT |
2010 | } |
2011 | ||
659ace58 KM |
2012 | /* |
2013 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2014 | * either for the first part or the tail. | |
2015 | */ | |
2016 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2017 | unsigned long addr, int new_below) | |
2018 | { | |
2019 | if (mm->map_count >= sysctl_max_map_count) | |
2020 | return -ENOMEM; | |
2021 | ||
2022 | return __split_vma(mm, vma, addr, new_below); | |
2023 | } | |
2024 | ||
1da177e4 LT |
2025 | /* Munmap is split into 2 main parts -- this part which finds |
2026 | * what needs doing, and the areas themselves, which do the | |
2027 | * work. This now handles partial unmappings. | |
2028 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
2029 | */ | |
2030 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
2031 | { | |
2032 | unsigned long end; | |
146425a3 | 2033 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
2034 | |
2035 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
2036 | return -EINVAL; | |
2037 | ||
2038 | if ((len = PAGE_ALIGN(len)) == 0) | |
2039 | return -EINVAL; | |
2040 | ||
2041 | /* Find the first overlapping VMA */ | |
9be34c9d | 2042 | vma = find_vma(mm, start); |
146425a3 | 2043 | if (!vma) |
1da177e4 | 2044 | return 0; |
9be34c9d | 2045 | prev = vma->vm_prev; |
146425a3 | 2046 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2047 | |
2048 | /* if it doesn't overlap, we have nothing.. */ | |
2049 | end = start + len; | |
146425a3 | 2050 | if (vma->vm_start >= end) |
1da177e4 LT |
2051 | return 0; |
2052 | ||
2053 | /* | |
2054 | * If we need to split any vma, do it now to save pain later. | |
2055 | * | |
2056 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2057 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2058 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2059 | */ | |
146425a3 | 2060 | if (start > vma->vm_start) { |
659ace58 KM |
2061 | int error; |
2062 | ||
2063 | /* | |
2064 | * Make sure that map_count on return from munmap() will | |
2065 | * not exceed its limit; but let map_count go just above | |
2066 | * its limit temporarily, to help free resources as expected. | |
2067 | */ | |
2068 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2069 | return -ENOMEM; | |
2070 | ||
2071 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2072 | if (error) |
2073 | return error; | |
146425a3 | 2074 | prev = vma; |
1da177e4 LT |
2075 | } |
2076 | ||
2077 | /* Does it split the last one? */ | |
2078 | last = find_vma(mm, end); | |
2079 | if (last && end > last->vm_start) { | |
659ace58 | 2080 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2081 | if (error) |
2082 | return error; | |
2083 | } | |
146425a3 | 2084 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 2085 | |
ba470de4 RR |
2086 | /* |
2087 | * unlock any mlock()ed ranges before detaching vmas | |
2088 | */ | |
2089 | if (mm->locked_vm) { | |
2090 | struct vm_area_struct *tmp = vma; | |
2091 | while (tmp && tmp->vm_start < end) { | |
2092 | if (tmp->vm_flags & VM_LOCKED) { | |
2093 | mm->locked_vm -= vma_pages(tmp); | |
2094 | munlock_vma_pages_all(tmp); | |
2095 | } | |
2096 | tmp = tmp->vm_next; | |
2097 | } | |
2098 | } | |
2099 | ||
1da177e4 LT |
2100 | /* |
2101 | * Remove the vma's, and unmap the actual pages | |
2102 | */ | |
146425a3 HD |
2103 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2104 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
2105 | |
2106 | /* Fix up all other VM information */ | |
2c0b3814 | 2107 | remove_vma_list(mm, vma); |
1da177e4 LT |
2108 | |
2109 | return 0; | |
2110 | } | |
1da177e4 | 2111 | |
bfce281c | 2112 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2113 | { |
2114 | int ret; | |
bfce281c | 2115 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
2116 | |
2117 | down_write(&mm->mmap_sem); | |
a46ef99d | 2118 | ret = do_munmap(mm, start, len); |
1da177e4 LT |
2119 | up_write(&mm->mmap_sem); |
2120 | return ret; | |
2121 | } | |
a46ef99d LT |
2122 | EXPORT_SYMBOL(vm_munmap); |
2123 | ||
2124 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2125 | { | |
2126 | profile_munmap(addr); | |
bfce281c | 2127 | return vm_munmap(addr, len); |
a46ef99d | 2128 | } |
1da177e4 LT |
2129 | |
2130 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
2131 | { | |
a241ec65 | 2132 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2133 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2134 | WARN_ON(1); | |
2135 | up_read(&mm->mmap_sem); | |
2136 | } | |
2137 | #endif | |
2138 | } | |
2139 | ||
2140 | /* | |
2141 | * this is really a simplified "do_mmap". it only handles | |
2142 | * anonymous maps. eventually we may be able to do some | |
2143 | * brk-specific accounting here. | |
2144 | */ | |
e4eb1ff6 | 2145 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
1da177e4 LT |
2146 | { |
2147 | struct mm_struct * mm = current->mm; | |
2148 | struct vm_area_struct * vma, * prev; | |
2149 | unsigned long flags; | |
2150 | struct rb_node ** rb_link, * rb_parent; | |
2151 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 2152 | int error; |
1da177e4 LT |
2153 | |
2154 | len = PAGE_ALIGN(len); | |
2155 | if (!len) | |
2156 | return addr; | |
2157 | ||
3a459756 KK |
2158 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2159 | ||
2c6a1016 AV |
2160 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
2161 | if (error & ~PAGE_MASK) | |
3a459756 KK |
2162 | return error; |
2163 | ||
1da177e4 LT |
2164 | /* |
2165 | * mlock MCL_FUTURE? | |
2166 | */ | |
2167 | if (mm->def_flags & VM_LOCKED) { | |
2168 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
2169 | locked = len >> PAGE_SHIFT; |
2170 | locked += mm->locked_vm; | |
59e99e5b | 2171 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 2172 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
2173 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
2174 | return -EAGAIN; | |
2175 | } | |
2176 | ||
2177 | /* | |
2178 | * mm->mmap_sem is required to protect against another thread | |
2179 | * changing the mappings in case we sleep. | |
2180 | */ | |
2181 | verify_mm_writelocked(mm); | |
2182 | ||
2183 | /* | |
2184 | * Clear old maps. this also does some error checking for us | |
2185 | */ | |
2186 | munmap_back: | |
6597d783 | 2187 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
2188 | if (do_munmap(mm, addr, len)) |
2189 | return -ENOMEM; | |
2190 | goto munmap_back; | |
2191 | } | |
2192 | ||
2193 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2194 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2195 | return -ENOMEM; |
2196 | ||
2197 | if (mm->map_count > sysctl_max_map_count) | |
2198 | return -ENOMEM; | |
2199 | ||
191c5424 | 2200 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2201 | return -ENOMEM; |
2202 | ||
1da177e4 | 2203 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2204 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2205 | NULL, NULL, pgoff, NULL); | |
2206 | if (vma) | |
1da177e4 LT |
2207 | goto out; |
2208 | ||
2209 | /* | |
2210 | * create a vma struct for an anonymous mapping | |
2211 | */ | |
c5e3b83e | 2212 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2213 | if (!vma) { |
2214 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2215 | return -ENOMEM; | |
2216 | } | |
1da177e4 | 2217 | |
5beb4930 | 2218 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2219 | vma->vm_mm = mm; |
2220 | vma->vm_start = addr; | |
2221 | vma->vm_end = addr + len; | |
2222 | vma->vm_pgoff = pgoff; | |
2223 | vma->vm_flags = flags; | |
3ed75eb8 | 2224 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2225 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2226 | out: | |
3af9e859 | 2227 | perf_event_mmap(vma); |
1da177e4 LT |
2228 | mm->total_vm += len >> PAGE_SHIFT; |
2229 | if (flags & VM_LOCKED) { | |
ba470de4 RR |
2230 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
2231 | mm->locked_vm += (len >> PAGE_SHIFT); | |
1da177e4 LT |
2232 | } |
2233 | return addr; | |
2234 | } | |
2235 | ||
e4eb1ff6 LT |
2236 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
2237 | { | |
2238 | struct mm_struct *mm = current->mm; | |
2239 | unsigned long ret; | |
2240 | ||
2241 | down_write(&mm->mmap_sem); | |
2242 | ret = do_brk(addr, len); | |
2243 | up_write(&mm->mmap_sem); | |
2244 | return ret; | |
2245 | } | |
2246 | EXPORT_SYMBOL(vm_brk); | |
1da177e4 LT |
2247 | |
2248 | /* Release all mmaps. */ | |
2249 | void exit_mmap(struct mm_struct *mm) | |
2250 | { | |
d16dfc55 | 2251 | struct mmu_gather tlb; |
ba470de4 | 2252 | struct vm_area_struct *vma; |
1da177e4 LT |
2253 | unsigned long nr_accounted = 0; |
2254 | ||
d6dd61c8 | 2255 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2256 | mmu_notifier_release(mm); |
d6dd61c8 | 2257 | |
ba470de4 RR |
2258 | if (mm->locked_vm) { |
2259 | vma = mm->mmap; | |
2260 | while (vma) { | |
2261 | if (vma->vm_flags & VM_LOCKED) | |
2262 | munlock_vma_pages_all(vma); | |
2263 | vma = vma->vm_next; | |
2264 | } | |
2265 | } | |
9480c53e JF |
2266 | |
2267 | arch_exit_mmap(mm); | |
2268 | ||
ba470de4 | 2269 | vma = mm->mmap; |
9480c53e JF |
2270 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2271 | return; | |
2272 | ||
1da177e4 | 2273 | lru_add_drain(); |
1da177e4 | 2274 | flush_cache_mm(mm); |
d16dfc55 | 2275 | tlb_gather_mmu(&tlb, mm, 1); |
901608d9 | 2276 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2277 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
4f74d2c8 | 2278 | unmap_vmas(&tlb, vma, 0, -1); |
9ba69294 | 2279 | |
d16dfc55 | 2280 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
853f5e26 | 2281 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 2282 | |
1da177e4 | 2283 | /* |
8f4f8c16 HD |
2284 | * Walk the list again, actually closing and freeing it, |
2285 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2286 | */ |
4f74d2c8 LT |
2287 | while (vma) { |
2288 | if (vma->vm_flags & VM_ACCOUNT) | |
2289 | nr_accounted += vma_pages(vma); | |
a8fb5618 | 2290 | vma = remove_vma(vma); |
4f74d2c8 LT |
2291 | } |
2292 | vm_unacct_memory(nr_accounted); | |
e0da382c | 2293 | |
f9aed62a | 2294 | WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
2295 | } |
2296 | ||
2297 | /* Insert vm structure into process list sorted by address | |
2298 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
3d48ae45 | 2299 | * then i_mmap_mutex is taken here. |
1da177e4 | 2300 | */ |
6597d783 | 2301 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2302 | { |
6597d783 HD |
2303 | struct vm_area_struct *prev; |
2304 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
2305 | |
2306 | /* | |
2307 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2308 | * until its first write fault, when page's anon_vma and index | |
2309 | * are set. But now set the vm_pgoff it will almost certainly | |
2310 | * end up with (unless mremap moves it elsewhere before that | |
2311 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2312 | * | |
2313 | * By setting it to reflect the virtual start address of the | |
2314 | * vma, merges and splits can happen in a seamless way, just | |
2315 | * using the existing file pgoff checks and manipulations. | |
2316 | * Similarly in do_mmap_pgoff and in do_brk. | |
2317 | */ | |
2318 | if (!vma->vm_file) { | |
2319 | BUG_ON(vma->anon_vma); | |
2320 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2321 | } | |
6597d783 HD |
2322 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
2323 | &prev, &rb_link, &rb_parent)) | |
1da177e4 | 2324 | return -ENOMEM; |
2fd4ef85 | 2325 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2326 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2327 | return -ENOMEM; |
2b144498 | 2328 | |
1da177e4 LT |
2329 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2330 | return 0; | |
2331 | } | |
2332 | ||
2333 | /* | |
2334 | * Copy the vma structure to a new location in the same mm, | |
2335 | * prior to moving page table entries, to effect an mremap move. | |
2336 | */ | |
2337 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
2338 | unsigned long addr, unsigned long len, pgoff_t pgoff) | |
2339 | { | |
2340 | struct vm_area_struct *vma = *vmap; | |
2341 | unsigned long vma_start = vma->vm_start; | |
2342 | struct mm_struct *mm = vma->vm_mm; | |
2343 | struct vm_area_struct *new_vma, *prev; | |
2344 | struct rb_node **rb_link, *rb_parent; | |
2345 | struct mempolicy *pol; | |
948f017b | 2346 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
2347 | |
2348 | /* | |
2349 | * If anonymous vma has not yet been faulted, update new pgoff | |
2350 | * to match new location, to increase its chance of merging. | |
2351 | */ | |
948f017b | 2352 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
1da177e4 | 2353 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
2354 | faulted_in_anon_vma = false; |
2355 | } | |
1da177e4 | 2356 | |
6597d783 HD |
2357 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
2358 | return NULL; /* should never get here */ | |
1da177e4 LT |
2359 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
2360 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2361 | if (new_vma) { | |
2362 | /* | |
2363 | * Source vma may have been merged into new_vma | |
2364 | */ | |
948f017b AA |
2365 | if (unlikely(vma_start >= new_vma->vm_start && |
2366 | vma_start < new_vma->vm_end)) { | |
2367 | /* | |
2368 | * The only way we can get a vma_merge with | |
2369 | * self during an mremap is if the vma hasn't | |
2370 | * been faulted in yet and we were allowed to | |
2371 | * reset the dst vma->vm_pgoff to the | |
2372 | * destination address of the mremap to allow | |
2373 | * the merge to happen. mremap must change the | |
2374 | * vm_pgoff linearity between src and dst vmas | |
2375 | * (in turn preventing a vma_merge) to be | |
2376 | * safe. It is only safe to keep the vm_pgoff | |
2377 | * linear if there are no pages mapped yet. | |
2378 | */ | |
2379 | VM_BUG_ON(faulted_in_anon_vma); | |
1da177e4 | 2380 | *vmap = new_vma; |
948f017b AA |
2381 | } else |
2382 | anon_vma_moveto_tail(new_vma); | |
1da177e4 | 2383 | } else { |
e94b1766 | 2384 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2385 | if (new_vma) { |
2386 | *new_vma = *vma; | |
846a16bf | 2387 | pol = mpol_dup(vma_policy(vma)); |
5beb4930 RR |
2388 | if (IS_ERR(pol)) |
2389 | goto out_free_vma; | |
2390 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); | |
2391 | if (anon_vma_clone(new_vma, vma)) | |
2392 | goto out_free_mempol; | |
1da177e4 LT |
2393 | vma_set_policy(new_vma, pol); |
2394 | new_vma->vm_start = addr; | |
2395 | new_vma->vm_end = addr + len; | |
2396 | new_vma->vm_pgoff = pgoff; | |
e9714acf | 2397 | if (new_vma->vm_file) |
1da177e4 LT |
2398 | get_file(new_vma->vm_file); |
2399 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
2400 | new_vma->vm_ops->open(new_vma); | |
2401 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
2402 | } | |
2403 | } | |
2404 | return new_vma; | |
5beb4930 RR |
2405 | |
2406 | out_free_mempol: | |
2407 | mpol_put(pol); | |
2408 | out_free_vma: | |
2409 | kmem_cache_free(vm_area_cachep, new_vma); | |
2410 | return NULL; | |
1da177e4 | 2411 | } |
119f657c | 2412 | |
2413 | /* | |
2414 | * Return true if the calling process may expand its vm space by the passed | |
2415 | * number of pages | |
2416 | */ | |
2417 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2418 | { | |
2419 | unsigned long cur = mm->total_vm; /* pages */ | |
2420 | unsigned long lim; | |
2421 | ||
59e99e5b | 2422 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
119f657c | 2423 | |
2424 | if (cur + npages > lim) | |
2425 | return 0; | |
2426 | return 1; | |
2427 | } | |
fa5dc22f RM |
2428 | |
2429 | ||
b1d0e4f5 NP |
2430 | static int special_mapping_fault(struct vm_area_struct *vma, |
2431 | struct vm_fault *vmf) | |
fa5dc22f | 2432 | { |
b1d0e4f5 | 2433 | pgoff_t pgoff; |
fa5dc22f RM |
2434 | struct page **pages; |
2435 | ||
b1d0e4f5 NP |
2436 | /* |
2437 | * special mappings have no vm_file, and in that case, the mm | |
2438 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2439 | * We are allowed to do this because we are the mm; do not copy | |
2440 | * this code into drivers! | |
2441 | */ | |
2442 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2443 | |
b1d0e4f5 NP |
2444 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2445 | pgoff--; | |
fa5dc22f RM |
2446 | |
2447 | if (*pages) { | |
2448 | struct page *page = *pages; | |
2449 | get_page(page); | |
b1d0e4f5 NP |
2450 | vmf->page = page; |
2451 | return 0; | |
fa5dc22f RM |
2452 | } |
2453 | ||
b1d0e4f5 | 2454 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2455 | } |
2456 | ||
2457 | /* | |
2458 | * Having a close hook prevents vma merging regardless of flags. | |
2459 | */ | |
2460 | static void special_mapping_close(struct vm_area_struct *vma) | |
2461 | { | |
2462 | } | |
2463 | ||
f0f37e2f | 2464 | static const struct vm_operations_struct special_mapping_vmops = { |
fa5dc22f | 2465 | .close = special_mapping_close, |
b1d0e4f5 | 2466 | .fault = special_mapping_fault, |
fa5dc22f RM |
2467 | }; |
2468 | ||
2469 | /* | |
2470 | * Called with mm->mmap_sem held for writing. | |
2471 | * Insert a new vma covering the given region, with the given flags. | |
2472 | * Its pages are supplied by the given array of struct page *. | |
2473 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2474 | * The region past the last page supplied will always produce SIGBUS. | |
2475 | * The array pointer and the pages it points to are assumed to stay alive | |
2476 | * for as long as this mapping might exist. | |
2477 | */ | |
2478 | int install_special_mapping(struct mm_struct *mm, | |
2479 | unsigned long addr, unsigned long len, | |
2480 | unsigned long vm_flags, struct page **pages) | |
2481 | { | |
462e635e | 2482 | int ret; |
fa5dc22f RM |
2483 | struct vm_area_struct *vma; |
2484 | ||
2485 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2486 | if (unlikely(vma == NULL)) | |
2487 | return -ENOMEM; | |
2488 | ||
5beb4930 | 2489 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
2490 | vma->vm_mm = mm; |
2491 | vma->vm_start = addr; | |
2492 | vma->vm_end = addr + len; | |
2493 | ||
2f98735c | 2494 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
3ed75eb8 | 2495 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2496 | |
2497 | vma->vm_ops = &special_mapping_vmops; | |
2498 | vma->vm_private_data = pages; | |
2499 | ||
462e635e TO |
2500 | ret = insert_vm_struct(mm, vma); |
2501 | if (ret) | |
2502 | goto out; | |
fa5dc22f RM |
2503 | |
2504 | mm->total_vm += len >> PAGE_SHIFT; | |
2505 | ||
cdd6c482 | 2506 | perf_event_mmap(vma); |
089dd79d | 2507 | |
fa5dc22f | 2508 | return 0; |
462e635e TO |
2509 | |
2510 | out: | |
2511 | kmem_cache_free(vm_area_cachep, vma); | |
2512 | return ret; | |
fa5dc22f | 2513 | } |
7906d00c AA |
2514 | |
2515 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
2516 | ||
454ed842 | 2517 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 2518 | { |
012f1800 | 2519 | if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { |
7906d00c AA |
2520 | /* |
2521 | * The LSB of head.next can't change from under us | |
2522 | * because we hold the mm_all_locks_mutex. | |
2523 | */ | |
2b575eb6 | 2524 | mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem); |
7906d00c AA |
2525 | /* |
2526 | * We can safely modify head.next after taking the | |
2b575eb6 | 2527 | * anon_vma->root->mutex. If some other vma in this mm shares |
7906d00c AA |
2528 | * the same anon_vma we won't take it again. |
2529 | * | |
2530 | * No need of atomic instructions here, head.next | |
2531 | * can't change from under us thanks to the | |
2b575eb6 | 2532 | * anon_vma->root->mutex. |
7906d00c AA |
2533 | */ |
2534 | if (__test_and_set_bit(0, (unsigned long *) | |
012f1800 | 2535 | &anon_vma->root->head.next)) |
7906d00c AA |
2536 | BUG(); |
2537 | } | |
2538 | } | |
2539 | ||
454ed842 | 2540 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
2541 | { |
2542 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2543 | /* | |
2544 | * AS_MM_ALL_LOCKS can't change from under us because | |
2545 | * we hold the mm_all_locks_mutex. | |
2546 | * | |
2547 | * Operations on ->flags have to be atomic because | |
2548 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
2549 | * mm_all_locks_mutex, there may be other cpus | |
2550 | * changing other bitflags in parallel to us. | |
2551 | */ | |
2552 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
2553 | BUG(); | |
3d48ae45 | 2554 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
7906d00c AA |
2555 | } |
2556 | } | |
2557 | ||
2558 | /* | |
2559 | * This operation locks against the VM for all pte/vma/mm related | |
2560 | * operations that could ever happen on a certain mm. This includes | |
2561 | * vmtruncate, try_to_unmap, and all page faults. | |
2562 | * | |
2563 | * The caller must take the mmap_sem in write mode before calling | |
2564 | * mm_take_all_locks(). The caller isn't allowed to release the | |
2565 | * mmap_sem until mm_drop_all_locks() returns. | |
2566 | * | |
2567 | * mmap_sem in write mode is required in order to block all operations | |
2568 | * that could modify pagetables and free pages without need of | |
2569 | * altering the vma layout (for example populate_range() with | |
2570 | * nonlinear vmas). It's also needed in write mode to avoid new | |
2571 | * anon_vmas to be associated with existing vmas. | |
2572 | * | |
2573 | * A single task can't take more than one mm_take_all_locks() in a row | |
2574 | * or it would deadlock. | |
2575 | * | |
2576 | * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in | |
2577 | * mapping->flags avoid to take the same lock twice, if more than one | |
2578 | * vma in this mm is backed by the same anon_vma or address_space. | |
2579 | * | |
2580 | * We can take all the locks in random order because the VM code | |
2b575eb6 | 2581 | * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never |
7906d00c AA |
2582 | * takes more than one of them in a row. Secondly we're protected |
2583 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
2584 | * | |
2585 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
2586 | * that may have to take thousand of locks. | |
2587 | * | |
2588 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
2589 | */ | |
2590 | int mm_take_all_locks(struct mm_struct *mm) | |
2591 | { | |
2592 | struct vm_area_struct *vma; | |
5beb4930 | 2593 | struct anon_vma_chain *avc; |
7906d00c AA |
2594 | |
2595 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2596 | ||
2597 | mutex_lock(&mm_all_locks_mutex); | |
2598 | ||
2599 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2600 | if (signal_pending(current)) | |
2601 | goto out_unlock; | |
7906d00c | 2602 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 2603 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 2604 | } |
7cd5a02f PZ |
2605 | |
2606 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2607 | if (signal_pending(current)) | |
2608 | goto out_unlock; | |
2609 | if (vma->anon_vma) | |
5beb4930 RR |
2610 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2611 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 2612 | } |
7cd5a02f | 2613 | |
584cff54 | 2614 | return 0; |
7906d00c AA |
2615 | |
2616 | out_unlock: | |
584cff54 KC |
2617 | mm_drop_all_locks(mm); |
2618 | return -EINTR; | |
7906d00c AA |
2619 | } |
2620 | ||
2621 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
2622 | { | |
012f1800 | 2623 | if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { |
7906d00c AA |
2624 | /* |
2625 | * The LSB of head.next can't change to 0 from under | |
2626 | * us because we hold the mm_all_locks_mutex. | |
2627 | * | |
2628 | * We must however clear the bitflag before unlocking | |
2629 | * the vma so the users using the anon_vma->head will | |
2630 | * never see our bitflag. | |
2631 | * | |
2632 | * No need of atomic instructions here, head.next | |
2633 | * can't change from under us until we release the | |
2b575eb6 | 2634 | * anon_vma->root->mutex. |
7906d00c AA |
2635 | */ |
2636 | if (!__test_and_clear_bit(0, (unsigned long *) | |
012f1800 | 2637 | &anon_vma->root->head.next)) |
7906d00c | 2638 | BUG(); |
cba48b98 | 2639 | anon_vma_unlock(anon_vma); |
7906d00c AA |
2640 | } |
2641 | } | |
2642 | ||
2643 | static void vm_unlock_mapping(struct address_space *mapping) | |
2644 | { | |
2645 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2646 | /* | |
2647 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
2648 | * because we hold the mm_all_locks_mutex. | |
2649 | */ | |
3d48ae45 | 2650 | mutex_unlock(&mapping->i_mmap_mutex); |
7906d00c AA |
2651 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
2652 | &mapping->flags)) | |
2653 | BUG(); | |
2654 | } | |
2655 | } | |
2656 | ||
2657 | /* | |
2658 | * The mmap_sem cannot be released by the caller until | |
2659 | * mm_drop_all_locks() returns. | |
2660 | */ | |
2661 | void mm_drop_all_locks(struct mm_struct *mm) | |
2662 | { | |
2663 | struct vm_area_struct *vma; | |
5beb4930 | 2664 | struct anon_vma_chain *avc; |
7906d00c AA |
2665 | |
2666 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2667 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
2668 | ||
2669 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2670 | if (vma->anon_vma) | |
5beb4930 RR |
2671 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2672 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
2673 | if (vma->vm_file && vma->vm_file->f_mapping) |
2674 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
2675 | } | |
2676 | ||
2677 | mutex_unlock(&mm_all_locks_mutex); | |
2678 | } | |
8feae131 DH |
2679 | |
2680 | /* | |
2681 | * initialise the VMA slab | |
2682 | */ | |
2683 | void __init mmap_init(void) | |
2684 | { | |
00a62ce9 KM |
2685 | int ret; |
2686 | ||
2687 | ret = percpu_counter_init(&vm_committed_as, 0); | |
2688 | VM_BUG_ON(ret); | |
8feae131 | 2689 | } |