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 | ||
e8420a8e | 9 | #include <linux/kernel.h> |
1da177e4 | 10 | #include <linux/slab.h> |
4af3c9cc | 11 | #include <linux/backing-dev.h> |
1da177e4 LT |
12 | #include <linux/mm.h> |
13 | #include <linux/shm.h> | |
14 | #include <linux/mman.h> | |
15 | #include <linux/pagemap.h> | |
16 | #include <linux/swap.h> | |
17 | #include <linux/syscalls.h> | |
c59ede7b | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | #include <linux/init.h> |
20 | #include <linux/file.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/personality.h> | |
23 | #include <linux/security.h> | |
24 | #include <linux/hugetlb.h> | |
25 | #include <linux/profile.h> | |
b95f1b31 | 26 | #include <linux/export.h> |
1da177e4 LT |
27 | #include <linux/mount.h> |
28 | #include <linux/mempolicy.h> | |
29 | #include <linux/rmap.h> | |
cddb8a5c | 30 | #include <linux/mmu_notifier.h> |
cdd6c482 | 31 | #include <linux/perf_event.h> |
120a795d | 32 | #include <linux/audit.h> |
b15d00b6 | 33 | #include <linux/khugepaged.h> |
2b144498 | 34 | #include <linux/uprobes.h> |
d3737187 | 35 | #include <linux/rbtree_augmented.h> |
cf4aebc2 | 36 | #include <linux/sched/sysctl.h> |
1640879a AS |
37 | #include <linux/notifier.h> |
38 | #include <linux/memory.h> | |
1da177e4 LT |
39 | |
40 | #include <asm/uaccess.h> | |
41 | #include <asm/cacheflush.h> | |
42 | #include <asm/tlb.h> | |
d6dd61c8 | 43 | #include <asm/mmu_context.h> |
1da177e4 | 44 | |
42b77728 JB |
45 | #include "internal.h" |
46 | ||
3a459756 KK |
47 | #ifndef arch_mmap_check |
48 | #define arch_mmap_check(addr, len, flags) (0) | |
49 | #endif | |
50 | ||
08e7d9b5 MS |
51 | #ifndef arch_rebalance_pgtables |
52 | #define arch_rebalance_pgtables(addr, len) (addr) | |
53 | #endif | |
54 | ||
e0da382c HD |
55 | static void unmap_region(struct mm_struct *mm, |
56 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
57 | unsigned long start, unsigned long end); | |
58 | ||
1da177e4 LT |
59 | /* description of effects of mapping type and prot in current implementation. |
60 | * this is due to the limited x86 page protection hardware. The expected | |
61 | * behavior is in parens: | |
62 | * | |
63 | * map_type prot | |
64 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
65 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
66 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
67 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
68 | * | |
69 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
70 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
71 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
72 | * | |
73 | */ | |
74 | pgprot_t protection_map[16] = { | |
75 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
76 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
77 | }; | |
78 | ||
804af2cf HD |
79 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
80 | { | |
b845f313 DK |
81 | return __pgprot(pgprot_val(protection_map[vm_flags & |
82 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
83 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
84 | } |
85 | EXPORT_SYMBOL(vm_get_page_prot); | |
86 | ||
34679d7e SL |
87 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
88 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ | |
49f0ce5f | 89 | unsigned long sysctl_overcommit_kbytes __read_mostly; |
c3d8c141 | 90 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
c9b1d098 | 91 | unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */ |
4eeab4f5 | 92 | unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */ |
34679d7e SL |
93 | /* |
94 | * Make sure vm_committed_as in one cacheline and not cacheline shared with | |
95 | * other variables. It can be updated by several CPUs frequently. | |
96 | */ | |
97 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; | |
1da177e4 | 98 | |
997071bc S |
99 | /* |
100 | * The global memory commitment made in the system can be a metric | |
101 | * that can be used to drive ballooning decisions when Linux is hosted | |
102 | * as a guest. On Hyper-V, the host implements a policy engine for dynamically | |
103 | * balancing memory across competing virtual machines that are hosted. | |
104 | * Several metrics drive this policy engine including the guest reported | |
105 | * memory commitment. | |
106 | */ | |
107 | unsigned long vm_memory_committed(void) | |
108 | { | |
109 | return percpu_counter_read_positive(&vm_committed_as); | |
110 | } | |
111 | EXPORT_SYMBOL_GPL(vm_memory_committed); | |
112 | ||
1da177e4 LT |
113 | /* |
114 | * Check that a process has enough memory to allocate a new virtual | |
115 | * mapping. 0 means there is enough memory for the allocation to | |
116 | * succeed and -ENOMEM implies there is not. | |
117 | * | |
118 | * We currently support three overcommit policies, which are set via the | |
119 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
120 | * | |
121 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
122 | * Additional code 2002 Jul 20 by Robert Love. | |
123 | * | |
124 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
125 | * | |
126 | * Note this is a helper function intended to be used by LSMs which | |
127 | * wish to use this logic. | |
128 | */ | |
34b4e4aa | 129 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 | 130 | { |
c9b1d098 | 131 | unsigned long free, allowed, reserve; |
1da177e4 LT |
132 | |
133 | vm_acct_memory(pages); | |
134 | ||
135 | /* | |
136 | * Sometimes we want to use more memory than we have | |
137 | */ | |
138 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
139 | return 0; | |
140 | ||
141 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
c15bef30 DF |
142 | free = global_page_state(NR_FREE_PAGES); |
143 | free += global_page_state(NR_FILE_PAGES); | |
144 | ||
145 | /* | |
146 | * shmem pages shouldn't be counted as free in this | |
147 | * case, they can't be purged, only swapped out, and | |
148 | * that won't affect the overall amount of available | |
149 | * memory in the system. | |
150 | */ | |
151 | free -= global_page_state(NR_SHMEM); | |
1da177e4 | 152 | |
ec8acf20 | 153 | free += get_nr_swap_pages(); |
1da177e4 LT |
154 | |
155 | /* | |
156 | * Any slabs which are created with the | |
157 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
158 | * which are reclaimable, under pressure. The dentry | |
159 | * cache and most inode caches should fall into this | |
160 | */ | |
972d1a7b | 161 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 | 162 | |
6d9f7839 HA |
163 | /* |
164 | * Leave reserved pages. The pages are not for anonymous pages. | |
165 | */ | |
c15bef30 | 166 | if (free <= totalreserve_pages) |
6d9f7839 HA |
167 | goto error; |
168 | else | |
c15bef30 | 169 | free -= totalreserve_pages; |
6d9f7839 HA |
170 | |
171 | /* | |
4eeab4f5 | 172 | * Reserve some for root |
6d9f7839 | 173 | */ |
1da177e4 | 174 | if (!cap_sys_admin) |
4eeab4f5 | 175 | free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); |
1da177e4 LT |
176 | |
177 | if (free > pages) | |
178 | return 0; | |
6d9f7839 HA |
179 | |
180 | goto error; | |
1da177e4 LT |
181 | } |
182 | ||
00619bcc | 183 | allowed = vm_commit_limit(); |
1da177e4 | 184 | /* |
4eeab4f5 | 185 | * Reserve some for root |
1da177e4 LT |
186 | */ |
187 | if (!cap_sys_admin) | |
4eeab4f5 | 188 | allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); |
1da177e4 | 189 | |
c9b1d098 AS |
190 | /* |
191 | * Don't let a single process grow so big a user can't recover | |
192 | */ | |
193 | if (mm) { | |
194 | reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10); | |
195 | allowed -= min(mm->total_vm / 32, reserve); | |
196 | } | |
1da177e4 | 197 | |
00a62ce9 | 198 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 199 | return 0; |
6d9f7839 | 200 | error: |
1da177e4 LT |
201 | vm_unacct_memory(pages); |
202 | ||
203 | return -ENOMEM; | |
204 | } | |
205 | ||
1da177e4 | 206 | /* |
3d48ae45 | 207 | * Requires inode->i_mapping->i_mmap_mutex |
1da177e4 LT |
208 | */ |
209 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
210 | struct file *file, struct address_space *mapping) | |
211 | { | |
212 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 213 | atomic_inc(&file_inode(file)->i_writecount); |
1da177e4 LT |
214 | if (vma->vm_flags & VM_SHARED) |
215 | mapping->i_mmap_writable--; | |
216 | ||
217 | flush_dcache_mmap_lock(mapping); | |
218 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
6b2dbba8 | 219 | list_del_init(&vma->shared.nonlinear); |
1da177e4 | 220 | else |
6b2dbba8 | 221 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4 LT |
222 | flush_dcache_mmap_unlock(mapping); |
223 | } | |
224 | ||
225 | /* | |
6b2dbba8 | 226 | * Unlink a file-based vm structure from its interval tree, to hide |
a8fb5618 | 227 | * vma from rmap and vmtruncate before freeing its page tables. |
1da177e4 | 228 | */ |
a8fb5618 | 229 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
230 | { |
231 | struct file *file = vma->vm_file; | |
232 | ||
1da177e4 LT |
233 | if (file) { |
234 | struct address_space *mapping = file->f_mapping; | |
3d48ae45 | 235 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 236 | __remove_shared_vm_struct(vma, file, mapping); |
3d48ae45 | 237 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 238 | } |
a8fb5618 HD |
239 | } |
240 | ||
241 | /* | |
242 | * Close a vm structure and free it, returning the next. | |
243 | */ | |
244 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
245 | { | |
246 | struct vm_area_struct *next = vma->vm_next; | |
247 | ||
a8fb5618 | 248 | might_sleep(); |
1da177e4 LT |
249 | if (vma->vm_ops && vma->vm_ops->close) |
250 | vma->vm_ops->close(vma); | |
e9714acf | 251 | if (vma->vm_file) |
a8fb5618 | 252 | fput(vma->vm_file); |
f0be3d32 | 253 | mpol_put(vma_policy(vma)); |
1da177e4 | 254 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 255 | return next; |
1da177e4 LT |
256 | } |
257 | ||
e4eb1ff6 LT |
258 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
259 | ||
6a6160a7 | 260 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
261 | { |
262 | unsigned long rlim, retval; | |
263 | unsigned long newbrk, oldbrk; | |
264 | struct mm_struct *mm = current->mm; | |
a5b4592c | 265 | unsigned long min_brk; |
128557ff | 266 | bool populate; |
1da177e4 LT |
267 | |
268 | down_write(&mm->mmap_sem); | |
269 | ||
a5b4592c | 270 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
271 | /* |
272 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
273 | * randomize_va_space to 2, which will still cause mm->start_brk | |
274 | * to be arbitrarily shifted | |
275 | */ | |
4471a675 | 276 | if (current->brk_randomized) |
5520e894 JK |
277 | min_brk = mm->start_brk; |
278 | else | |
279 | min_brk = mm->end_data; | |
a5b4592c JK |
280 | #else |
281 | min_brk = mm->start_brk; | |
282 | #endif | |
283 | if (brk < min_brk) | |
1da177e4 | 284 | goto out; |
1e624196 RG |
285 | |
286 | /* | |
287 | * Check against rlimit here. If this check is done later after the test | |
288 | * of oldbrk with newbrk then it can escape the test and let the data | |
289 | * segment grow beyond its set limit the in case where the limit is | |
290 | * not page aligned -Ram Gupta | |
291 | */ | |
59e99e5b | 292 | rlim = rlimit(RLIMIT_DATA); |
c1d171a0 JK |
293 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
294 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
295 | goto out; |
296 | ||
1da177e4 LT |
297 | newbrk = PAGE_ALIGN(brk); |
298 | oldbrk = PAGE_ALIGN(mm->brk); | |
299 | if (oldbrk == newbrk) | |
300 | goto set_brk; | |
301 | ||
302 | /* Always allow shrinking brk. */ | |
303 | if (brk <= mm->brk) { | |
304 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
305 | goto set_brk; | |
306 | goto out; | |
307 | } | |
308 | ||
1da177e4 LT |
309 | /* Check against existing mmap mappings. */ |
310 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
311 | goto out; | |
312 | ||
313 | /* Ok, looks good - let it rip. */ | |
314 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
315 | goto out; | |
128557ff | 316 | |
1da177e4 LT |
317 | set_brk: |
318 | mm->brk = brk; | |
128557ff ML |
319 | populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; |
320 | up_write(&mm->mmap_sem); | |
321 | if (populate) | |
322 | mm_populate(oldbrk, newbrk - oldbrk); | |
323 | return brk; | |
324 | ||
1da177e4 LT |
325 | out: |
326 | retval = mm->brk; | |
327 | up_write(&mm->mmap_sem); | |
328 | return retval; | |
329 | } | |
330 | ||
d3737187 ML |
331 | static long vma_compute_subtree_gap(struct vm_area_struct *vma) |
332 | { | |
333 | unsigned long max, subtree_gap; | |
334 | max = vma->vm_start; | |
335 | if (vma->vm_prev) | |
336 | max -= vma->vm_prev->vm_end; | |
337 | if (vma->vm_rb.rb_left) { | |
338 | subtree_gap = rb_entry(vma->vm_rb.rb_left, | |
339 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
340 | if (subtree_gap > max) | |
341 | max = subtree_gap; | |
342 | } | |
343 | if (vma->vm_rb.rb_right) { | |
344 | subtree_gap = rb_entry(vma->vm_rb.rb_right, | |
345 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
346 | if (subtree_gap > max) | |
347 | max = subtree_gap; | |
348 | } | |
349 | return max; | |
350 | } | |
351 | ||
ed8ea815 | 352 | #ifdef CONFIG_DEBUG_VM_RB |
1da177e4 LT |
353 | static int browse_rb(struct rb_root *root) |
354 | { | |
5a0768f6 | 355 | int i = 0, j, bug = 0; |
1da177e4 LT |
356 | struct rb_node *nd, *pn = NULL; |
357 | unsigned long prev = 0, pend = 0; | |
358 | ||
359 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
360 | struct vm_area_struct *vma; | |
361 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
5a0768f6 ML |
362 | if (vma->vm_start < prev) { |
363 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev); | |
364 | bug = 1; | |
365 | } | |
366 | if (vma->vm_start < pend) { | |
1da177e4 | 367 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); |
5a0768f6 ML |
368 | bug = 1; |
369 | } | |
370 | if (vma->vm_start > vma->vm_end) { | |
371 | printk("vm_end %lx < vm_start %lx\n", | |
372 | vma->vm_end, vma->vm_start); | |
373 | bug = 1; | |
374 | } | |
375 | if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { | |
376 | printk("free gap %lx, correct %lx\n", | |
377 | vma->rb_subtree_gap, | |
378 | vma_compute_subtree_gap(vma)); | |
379 | bug = 1; | |
380 | } | |
1da177e4 LT |
381 | i++; |
382 | pn = nd; | |
d1af65d1 DM |
383 | prev = vma->vm_start; |
384 | pend = vma->vm_end; | |
1da177e4 LT |
385 | } |
386 | j = 0; | |
5a0768f6 | 387 | for (nd = pn; nd; nd = rb_prev(nd)) |
1da177e4 | 388 | j++; |
5a0768f6 ML |
389 | if (i != j) { |
390 | printk("backwards %d, forwards %d\n", j, i); | |
391 | bug = 1; | |
1da177e4 | 392 | } |
5a0768f6 | 393 | return bug ? -1 : i; |
1da177e4 LT |
394 | } |
395 | ||
d3737187 ML |
396 | static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) |
397 | { | |
398 | struct rb_node *nd; | |
399 | ||
400 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
401 | struct vm_area_struct *vma; | |
402 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
403 | BUG_ON(vma != ignore && | |
404 | vma->rb_subtree_gap != vma_compute_subtree_gap(vma)); | |
1da177e4 | 405 | } |
1da177e4 LT |
406 | } |
407 | ||
408 | void validate_mm(struct mm_struct *mm) | |
409 | { | |
410 | int bug = 0; | |
411 | int i = 0; | |
5a0768f6 | 412 | unsigned long highest_address = 0; |
ed8ea815 ML |
413 | struct vm_area_struct *vma = mm->mmap; |
414 | while (vma) { | |
415 | struct anon_vma_chain *avc; | |
63c3b902 | 416 | vma_lock_anon_vma(vma); |
ed8ea815 ML |
417 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
418 | anon_vma_interval_tree_verify(avc); | |
63c3b902 | 419 | vma_unlock_anon_vma(vma); |
5a0768f6 | 420 | highest_address = vma->vm_end; |
ed8ea815 | 421 | vma = vma->vm_next; |
1da177e4 LT |
422 | i++; |
423 | } | |
5a0768f6 ML |
424 | if (i != mm->map_count) { |
425 | printk("map_count %d vm_next %d\n", mm->map_count, i); | |
426 | bug = 1; | |
427 | } | |
428 | if (highest_address != mm->highest_vm_end) { | |
429 | printk("mm->highest_vm_end %lx, found %lx\n", | |
430 | mm->highest_vm_end, highest_address); | |
431 | bug = 1; | |
432 | } | |
1da177e4 | 433 | i = browse_rb(&mm->mm_rb); |
5a0768f6 ML |
434 | if (i != mm->map_count) { |
435 | printk("map_count %d rb %d\n", mm->map_count, i); | |
436 | bug = 1; | |
437 | } | |
46a350ef | 438 | BUG_ON(bug); |
1da177e4 LT |
439 | } |
440 | #else | |
d3737187 | 441 | #define validate_mm_rb(root, ignore) do { } while (0) |
1da177e4 LT |
442 | #define validate_mm(mm) do { } while (0) |
443 | #endif | |
444 | ||
d3737187 ML |
445 | RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, |
446 | unsigned long, rb_subtree_gap, vma_compute_subtree_gap) | |
447 | ||
448 | /* | |
449 | * Update augmented rbtree rb_subtree_gap values after vma->vm_start or | |
450 | * vma->vm_prev->vm_end values changed, without modifying the vma's position | |
451 | * in the rbtree. | |
452 | */ | |
453 | static void vma_gap_update(struct vm_area_struct *vma) | |
454 | { | |
455 | /* | |
456 | * As it turns out, RB_DECLARE_CALLBACKS() already created a callback | |
457 | * function that does exacltly what we want. | |
458 | */ | |
459 | vma_gap_callbacks_propagate(&vma->vm_rb, NULL); | |
460 | } | |
461 | ||
462 | static inline void vma_rb_insert(struct vm_area_struct *vma, | |
463 | struct rb_root *root) | |
464 | { | |
465 | /* All rb_subtree_gap values must be consistent prior to insertion */ | |
466 | validate_mm_rb(root, NULL); | |
467 | ||
468 | rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
469 | } | |
470 | ||
471 | static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) | |
472 | { | |
473 | /* | |
474 | * All rb_subtree_gap values must be consistent prior to erase, | |
475 | * with the possible exception of the vma being erased. | |
476 | */ | |
477 | validate_mm_rb(root, vma); | |
478 | ||
479 | /* | |
480 | * Note rb_erase_augmented is a fairly large inline function, | |
481 | * so make sure we instantiate it only once with our desired | |
482 | * augmented rbtree callbacks. | |
483 | */ | |
484 | rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
485 | } | |
486 | ||
bf181b9f ML |
487 | /* |
488 | * vma has some anon_vma assigned, and is already inserted on that | |
489 | * anon_vma's interval trees. | |
490 | * | |
491 | * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the | |
492 | * vma must be removed from the anon_vma's interval trees using | |
493 | * anon_vma_interval_tree_pre_update_vma(). | |
494 | * | |
495 | * After the update, the vma will be reinserted using | |
496 | * anon_vma_interval_tree_post_update_vma(). | |
497 | * | |
498 | * The entire update must be protected by exclusive mmap_sem and by | |
499 | * the root anon_vma's mutex. | |
500 | */ | |
501 | static inline void | |
502 | anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) | |
503 | { | |
504 | struct anon_vma_chain *avc; | |
505 | ||
506 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
507 | anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); | |
508 | } | |
509 | ||
510 | static inline void | |
511 | anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) | |
512 | { | |
513 | struct anon_vma_chain *avc; | |
514 | ||
515 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
516 | anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); | |
517 | } | |
518 | ||
6597d783 HD |
519 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
520 | unsigned long end, struct vm_area_struct **pprev, | |
521 | struct rb_node ***rb_link, struct rb_node **rb_parent) | |
1da177e4 | 522 | { |
6597d783 | 523 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
1da177e4 LT |
524 | |
525 | __rb_link = &mm->mm_rb.rb_node; | |
526 | rb_prev = __rb_parent = NULL; | |
1da177e4 LT |
527 | |
528 | while (*__rb_link) { | |
529 | struct vm_area_struct *vma_tmp; | |
530 | ||
531 | __rb_parent = *__rb_link; | |
532 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
533 | ||
534 | if (vma_tmp->vm_end > addr) { | |
6597d783 HD |
535 | /* Fail if an existing vma overlaps the area */ |
536 | if (vma_tmp->vm_start < end) | |
537 | return -ENOMEM; | |
1da177e4 LT |
538 | __rb_link = &__rb_parent->rb_left; |
539 | } else { | |
540 | rb_prev = __rb_parent; | |
541 | __rb_link = &__rb_parent->rb_right; | |
542 | } | |
543 | } | |
544 | ||
545 | *pprev = NULL; | |
546 | if (rb_prev) | |
547 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
548 | *rb_link = __rb_link; | |
549 | *rb_parent = __rb_parent; | |
6597d783 | 550 | return 0; |
1da177e4 LT |
551 | } |
552 | ||
e8420a8e CH |
553 | static unsigned long count_vma_pages_range(struct mm_struct *mm, |
554 | unsigned long addr, unsigned long end) | |
555 | { | |
556 | unsigned long nr_pages = 0; | |
557 | struct vm_area_struct *vma; | |
558 | ||
559 | /* Find first overlaping mapping */ | |
560 | vma = find_vma_intersection(mm, addr, end); | |
561 | if (!vma) | |
562 | return 0; | |
563 | ||
564 | nr_pages = (min(end, vma->vm_end) - | |
565 | max(addr, vma->vm_start)) >> PAGE_SHIFT; | |
566 | ||
567 | /* Iterate over the rest of the overlaps */ | |
568 | for (vma = vma->vm_next; vma; vma = vma->vm_next) { | |
569 | unsigned long overlap_len; | |
570 | ||
571 | if (vma->vm_start > end) | |
572 | break; | |
573 | ||
574 | overlap_len = min(end, vma->vm_end) - vma->vm_start; | |
575 | nr_pages += overlap_len >> PAGE_SHIFT; | |
576 | } | |
577 | ||
578 | return nr_pages; | |
579 | } | |
580 | ||
1da177e4 LT |
581 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
582 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
583 | { | |
d3737187 ML |
584 | /* Update tracking information for the gap following the new vma. */ |
585 | if (vma->vm_next) | |
586 | vma_gap_update(vma->vm_next); | |
587 | else | |
588 | mm->highest_vm_end = vma->vm_end; | |
589 | ||
590 | /* | |
591 | * vma->vm_prev wasn't known when we followed the rbtree to find the | |
592 | * correct insertion point for that vma. As a result, we could not | |
593 | * update the vma vm_rb parents rb_subtree_gap values on the way down. | |
594 | * So, we first insert the vma with a zero rb_subtree_gap value | |
595 | * (to be consistent with what we did on the way down), and then | |
596 | * immediately update the gap to the correct value. Finally we | |
597 | * rebalance the rbtree after all augmented values have been set. | |
598 | */ | |
1da177e4 | 599 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
d3737187 ML |
600 | vma->rb_subtree_gap = 0; |
601 | vma_gap_update(vma); | |
602 | vma_rb_insert(vma, &mm->mm_rb); | |
1da177e4 LT |
603 | } |
604 | ||
cb8f488c | 605 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 606 | { |
48aae425 | 607 | struct file *file; |
1da177e4 LT |
608 | |
609 | file = vma->vm_file; | |
610 | if (file) { | |
611 | struct address_space *mapping = file->f_mapping; | |
612 | ||
613 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 614 | atomic_dec(&file_inode(file)->i_writecount); |
1da177e4 LT |
615 | if (vma->vm_flags & VM_SHARED) |
616 | mapping->i_mmap_writable++; | |
617 | ||
618 | flush_dcache_mmap_lock(mapping); | |
619 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
620 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
621 | else | |
6b2dbba8 | 622 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4 LT |
623 | flush_dcache_mmap_unlock(mapping); |
624 | } | |
625 | } | |
626 | ||
627 | static void | |
628 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
629 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
630 | struct rb_node *rb_parent) | |
631 | { | |
632 | __vma_link_list(mm, vma, prev, rb_parent); | |
633 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
634 | } |
635 | ||
636 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
637 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
638 | struct rb_node *rb_parent) | |
639 | { | |
640 | struct address_space *mapping = NULL; | |
641 | ||
642 | if (vma->vm_file) | |
643 | mapping = vma->vm_file->f_mapping; | |
644 | ||
97a89413 | 645 | if (mapping) |
3d48ae45 | 646 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 LT |
647 | |
648 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
649 | __vma_link_file(vma); | |
650 | ||
1da177e4 | 651 | if (mapping) |
3d48ae45 | 652 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
653 | |
654 | mm->map_count++; | |
655 | validate_mm(mm); | |
656 | } | |
657 | ||
658 | /* | |
88f6b4c3 | 659 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
6b2dbba8 | 660 | * mm's list and rbtree. It has already been inserted into the interval tree. |
1da177e4 | 661 | */ |
48aae425 | 662 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 663 | { |
6597d783 | 664 | struct vm_area_struct *prev; |
48aae425 | 665 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 666 | |
6597d783 HD |
667 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
668 | &prev, &rb_link, &rb_parent)) | |
669 | BUG(); | |
1da177e4 LT |
670 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
671 | mm->map_count++; | |
672 | } | |
673 | ||
674 | static inline void | |
675 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
676 | struct vm_area_struct *prev) | |
677 | { | |
d3737187 | 678 | struct vm_area_struct *next; |
297c5eee | 679 | |
d3737187 ML |
680 | vma_rb_erase(vma, &mm->mm_rb); |
681 | prev->vm_next = next = vma->vm_next; | |
297c5eee LT |
682 | if (next) |
683 | next->vm_prev = prev; | |
1da177e4 LT |
684 | if (mm->mmap_cache == vma) |
685 | mm->mmap_cache = prev; | |
686 | } | |
687 | ||
688 | /* | |
689 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
690 | * is already present in an i_mmap tree without adjusting the tree. | |
691 | * The following helper function should be used when such adjustments | |
692 | * are necessary. The "insert" vma (if any) is to be inserted | |
693 | * before we drop the necessary locks. | |
694 | */ | |
5beb4930 | 695 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
696 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
697 | { | |
698 | struct mm_struct *mm = vma->vm_mm; | |
699 | struct vm_area_struct *next = vma->vm_next; | |
700 | struct vm_area_struct *importer = NULL; | |
701 | struct address_space *mapping = NULL; | |
6b2dbba8 | 702 | struct rb_root *root = NULL; |
012f1800 | 703 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 704 | struct file *file = vma->vm_file; |
d3737187 | 705 | bool start_changed = false, end_changed = false; |
1da177e4 LT |
706 | long adjust_next = 0; |
707 | int remove_next = 0; | |
708 | ||
709 | if (next && !insert) { | |
287d97ac LT |
710 | struct vm_area_struct *exporter = NULL; |
711 | ||
1da177e4 LT |
712 | if (end >= next->vm_end) { |
713 | /* | |
714 | * vma expands, overlapping all the next, and | |
715 | * perhaps the one after too (mprotect case 6). | |
716 | */ | |
717 | again: remove_next = 1 + (end > next->vm_end); | |
718 | end = next->vm_end; | |
287d97ac | 719 | exporter = next; |
1da177e4 LT |
720 | importer = vma; |
721 | } else if (end > next->vm_start) { | |
722 | /* | |
723 | * vma expands, overlapping part of the next: | |
724 | * mprotect case 5 shifting the boundary up. | |
725 | */ | |
726 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 727 | exporter = next; |
1da177e4 LT |
728 | importer = vma; |
729 | } else if (end < vma->vm_end) { | |
730 | /* | |
731 | * vma shrinks, and !insert tells it's not | |
732 | * split_vma inserting another: so it must be | |
733 | * mprotect case 4 shifting the boundary down. | |
734 | */ | |
735 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
287d97ac | 736 | exporter = vma; |
1da177e4 LT |
737 | importer = next; |
738 | } | |
1da177e4 | 739 | |
5beb4930 RR |
740 | /* |
741 | * Easily overlooked: when mprotect shifts the boundary, | |
742 | * make sure the expanding vma has anon_vma set if the | |
743 | * shrinking vma had, to cover any anon pages imported. | |
744 | */ | |
287d97ac LT |
745 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
746 | if (anon_vma_clone(importer, exporter)) | |
5beb4930 | 747 | return -ENOMEM; |
287d97ac | 748 | importer->anon_vma = exporter->anon_vma; |
5beb4930 RR |
749 | } |
750 | } | |
751 | ||
1da177e4 LT |
752 | if (file) { |
753 | mapping = file->f_mapping; | |
682968e0 | 754 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
1da177e4 | 755 | root = &mapping->i_mmap; |
cbc91f71 | 756 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); |
682968e0 SD |
757 | |
758 | if (adjust_next) | |
cbc91f71 SD |
759 | uprobe_munmap(next, next->vm_start, |
760 | next->vm_end); | |
682968e0 SD |
761 | } |
762 | ||
3d48ae45 | 763 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 764 | if (insert) { |
1da177e4 | 765 | /* |
6b2dbba8 | 766 | * Put into interval tree now, so instantiated pages |
1da177e4 LT |
767 | * are visible to arm/parisc __flush_dcache_page |
768 | * throughout; but we cannot insert into address | |
769 | * space until vma start or end is updated. | |
770 | */ | |
771 | __vma_link_file(insert); | |
772 | } | |
773 | } | |
774 | ||
94fcc585 AA |
775 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
776 | ||
bf181b9f ML |
777 | anon_vma = vma->anon_vma; |
778 | if (!anon_vma && adjust_next) | |
779 | anon_vma = next->anon_vma; | |
780 | if (anon_vma) { | |
ca42b26a ML |
781 | VM_BUG_ON(adjust_next && next->anon_vma && |
782 | anon_vma != next->anon_vma); | |
4fc3f1d6 | 783 | anon_vma_lock_write(anon_vma); |
bf181b9f ML |
784 | anon_vma_interval_tree_pre_update_vma(vma); |
785 | if (adjust_next) | |
786 | anon_vma_interval_tree_pre_update_vma(next); | |
787 | } | |
012f1800 | 788 | |
1da177e4 LT |
789 | if (root) { |
790 | flush_dcache_mmap_lock(mapping); | |
6b2dbba8 | 791 | vma_interval_tree_remove(vma, root); |
1da177e4 | 792 | if (adjust_next) |
6b2dbba8 | 793 | vma_interval_tree_remove(next, root); |
1da177e4 LT |
794 | } |
795 | ||
d3737187 ML |
796 | if (start != vma->vm_start) { |
797 | vma->vm_start = start; | |
798 | start_changed = true; | |
799 | } | |
800 | if (end != vma->vm_end) { | |
801 | vma->vm_end = end; | |
802 | end_changed = true; | |
803 | } | |
1da177e4 LT |
804 | vma->vm_pgoff = pgoff; |
805 | if (adjust_next) { | |
806 | next->vm_start += adjust_next << PAGE_SHIFT; | |
807 | next->vm_pgoff += adjust_next; | |
808 | } | |
809 | ||
810 | if (root) { | |
811 | if (adjust_next) | |
6b2dbba8 ML |
812 | vma_interval_tree_insert(next, root); |
813 | vma_interval_tree_insert(vma, root); | |
1da177e4 LT |
814 | flush_dcache_mmap_unlock(mapping); |
815 | } | |
816 | ||
817 | if (remove_next) { | |
818 | /* | |
819 | * vma_merge has merged next into vma, and needs | |
820 | * us to remove next before dropping the locks. | |
821 | */ | |
822 | __vma_unlink(mm, next, vma); | |
823 | if (file) | |
824 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
825 | } else if (insert) { |
826 | /* | |
827 | * split_vma has split insert from vma, and needs | |
828 | * us to insert it before dropping the locks | |
829 | * (it may either follow vma or precede it). | |
830 | */ | |
831 | __insert_vm_struct(mm, insert); | |
d3737187 ML |
832 | } else { |
833 | if (start_changed) | |
834 | vma_gap_update(vma); | |
835 | if (end_changed) { | |
836 | if (!next) | |
837 | mm->highest_vm_end = end; | |
838 | else if (!adjust_next) | |
839 | vma_gap_update(next); | |
840 | } | |
1da177e4 LT |
841 | } |
842 | ||
bf181b9f ML |
843 | if (anon_vma) { |
844 | anon_vma_interval_tree_post_update_vma(vma); | |
845 | if (adjust_next) | |
846 | anon_vma_interval_tree_post_update_vma(next); | |
08b52706 | 847 | anon_vma_unlock_write(anon_vma); |
bf181b9f | 848 | } |
1da177e4 | 849 | if (mapping) |
3d48ae45 | 850 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 851 | |
2b144498 | 852 | if (root) { |
7b2d81d4 | 853 | uprobe_mmap(vma); |
2b144498 SD |
854 | |
855 | if (adjust_next) | |
7b2d81d4 | 856 | uprobe_mmap(next); |
2b144498 SD |
857 | } |
858 | ||
1da177e4 | 859 | if (remove_next) { |
925d1c40 | 860 | if (file) { |
cbc91f71 | 861 | uprobe_munmap(next, next->vm_start, next->vm_end); |
1da177e4 | 862 | fput(file); |
925d1c40 | 863 | } |
5beb4930 RR |
864 | if (next->anon_vma) |
865 | anon_vma_merge(vma, next); | |
1da177e4 | 866 | mm->map_count--; |
3964acd0 | 867 | mpol_put(vma_policy(next)); |
1da177e4 LT |
868 | kmem_cache_free(vm_area_cachep, next); |
869 | /* | |
870 | * In mprotect's case 6 (see comments on vma_merge), | |
871 | * we must remove another next too. It would clutter | |
872 | * up the code too much to do both in one go. | |
873 | */ | |
d3737187 ML |
874 | next = vma->vm_next; |
875 | if (remove_next == 2) | |
1da177e4 | 876 | goto again; |
d3737187 ML |
877 | else if (next) |
878 | vma_gap_update(next); | |
879 | else | |
880 | mm->highest_vm_end = end; | |
1da177e4 | 881 | } |
2b144498 | 882 | if (insert && file) |
7b2d81d4 | 883 | uprobe_mmap(insert); |
1da177e4 LT |
884 | |
885 | validate_mm(mm); | |
5beb4930 RR |
886 | |
887 | return 0; | |
1da177e4 LT |
888 | } |
889 | ||
890 | /* | |
891 | * If the vma has a ->close operation then the driver probably needs to release | |
892 | * per-vma resources, so we don't attempt to merge those. | |
893 | */ | |
1da177e4 LT |
894 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
895 | struct file *file, unsigned long vm_flags) | |
896 | { | |
0b173bc4 | 897 | if (vma->vm_flags ^ vm_flags) |
1da177e4 LT |
898 | return 0; |
899 | if (vma->vm_file != file) | |
900 | return 0; | |
901 | if (vma->vm_ops && vma->vm_ops->close) | |
902 | return 0; | |
903 | return 1; | |
904 | } | |
905 | ||
906 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
907 | struct anon_vma *anon_vma2, |
908 | struct vm_area_struct *vma) | |
1da177e4 | 909 | { |
965f55de SL |
910 | /* |
911 | * The list_is_singular() test is to avoid merging VMA cloned from | |
912 | * parents. This can improve scalability caused by anon_vma lock. | |
913 | */ | |
914 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
915 | list_is_singular(&vma->anon_vma_chain))) | |
916 | return 1; | |
917 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
918 | } |
919 | ||
920 | /* | |
921 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
922 | * in front of (at a lower virtual address and file offset than) the vma. | |
923 | * | |
924 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
925 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
926 | * | |
927 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
928 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
929 | * wrap, nor mmaps which cover the final page at index -1UL. | |
930 | */ | |
931 | static int | |
932 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
933 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
934 | { | |
935 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 936 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
937 | if (vma->vm_pgoff == vm_pgoff) |
938 | return 1; | |
939 | } | |
940 | return 0; | |
941 | } | |
942 | ||
943 | /* | |
944 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
945 | * beyond (at a higher virtual address and file offset than) the vma. | |
946 | * | |
947 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
948 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
949 | */ | |
950 | static int | |
951 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
952 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
953 | { | |
954 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 955 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 | 956 | pgoff_t vm_pglen; |
d6e93217 | 957 | vm_pglen = vma_pages(vma); |
1da177e4 LT |
958 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
959 | return 1; | |
960 | } | |
961 | return 0; | |
962 | } | |
963 | ||
964 | /* | |
965 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
966 | * whether that can be merged with its predecessor or its successor. | |
967 | * Or both (it neatly fills a hole). | |
968 | * | |
969 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
970 | * certain not to be mapped by the time vma_merge is called; but when | |
971 | * called for mprotect, it is certain to be already mapped (either at | |
972 | * an offset within prev, or at the start of next), and the flags of | |
973 | * this area are about to be changed to vm_flags - and the no-change | |
974 | * case has already been eliminated. | |
975 | * | |
976 | * The following mprotect cases have to be considered, where AAAA is | |
977 | * the area passed down from mprotect_fixup, never extending beyond one | |
978 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
979 | * | |
980 | * AAAA AAAA AAAA AAAA | |
981 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
982 | * cannot merge might become might become might become | |
983 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
984 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
985 | * mremap move: PPPPNNNNNNNN 8 | |
986 | * AAAA | |
987 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
988 | * might become case 1 below case 2 below case 3 below | |
989 | * | |
990 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
991 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
992 | */ | |
993 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
994 | struct vm_area_struct *prev, unsigned long addr, | |
995 | unsigned long end, unsigned long vm_flags, | |
996 | struct anon_vma *anon_vma, struct file *file, | |
997 | pgoff_t pgoff, struct mempolicy *policy) | |
998 | { | |
999 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
1000 | struct vm_area_struct *area, *next; | |
5beb4930 | 1001 | int err; |
1da177e4 LT |
1002 | |
1003 | /* | |
1004 | * We later require that vma->vm_flags == vm_flags, | |
1005 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
1006 | */ | |
1007 | if (vm_flags & VM_SPECIAL) | |
1008 | return NULL; | |
1009 | ||
1010 | if (prev) | |
1011 | next = prev->vm_next; | |
1012 | else | |
1013 | next = mm->mmap; | |
1014 | area = next; | |
1015 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
1016 | next = next->vm_next; | |
1017 | ||
1018 | /* | |
1019 | * Can it merge with the predecessor? | |
1020 | */ | |
1021 | if (prev && prev->vm_end == addr && | |
1022 | mpol_equal(vma_policy(prev), policy) && | |
1023 | can_vma_merge_after(prev, vm_flags, | |
1024 | anon_vma, file, pgoff)) { | |
1025 | /* | |
1026 | * OK, it can. Can we now merge in the successor as well? | |
1027 | */ | |
1028 | if (next && end == next->vm_start && | |
1029 | mpol_equal(policy, vma_policy(next)) && | |
1030 | can_vma_merge_before(next, vm_flags, | |
1031 | anon_vma, file, pgoff+pglen) && | |
1032 | is_mergeable_anon_vma(prev->anon_vma, | |
965f55de | 1033 | next->anon_vma, NULL)) { |
1da177e4 | 1034 | /* cases 1, 6 */ |
5beb4930 | 1035 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
1036 | next->vm_end, prev->vm_pgoff, NULL); |
1037 | } else /* cases 2, 5, 7 */ | |
5beb4930 | 1038 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 | 1039 | end, prev->vm_pgoff, NULL); |
5beb4930 RR |
1040 | if (err) |
1041 | return NULL; | |
b15d00b6 | 1042 | khugepaged_enter_vma_merge(prev); |
1da177e4 LT |
1043 | return prev; |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * Can this new request be merged in front of next? | |
1048 | */ | |
1049 | if (next && end == next->vm_start && | |
1050 | mpol_equal(policy, vma_policy(next)) && | |
1051 | can_vma_merge_before(next, vm_flags, | |
1052 | anon_vma, file, pgoff+pglen)) { | |
1053 | if (prev && addr < prev->vm_end) /* case 4 */ | |
5beb4930 | 1054 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
1055 | addr, prev->vm_pgoff, NULL); |
1056 | else /* cases 3, 8 */ | |
5beb4930 | 1057 | err = vma_adjust(area, addr, next->vm_end, |
1da177e4 | 1058 | next->vm_pgoff - pglen, NULL); |
5beb4930 RR |
1059 | if (err) |
1060 | return NULL; | |
b15d00b6 | 1061 | khugepaged_enter_vma_merge(area); |
1da177e4 LT |
1062 | return area; |
1063 | } | |
1064 | ||
1065 | return NULL; | |
1066 | } | |
1067 | ||
d0e9fe17 LT |
1068 | /* |
1069 | * Rough compatbility check to quickly see if it's even worth looking | |
1070 | * at sharing an anon_vma. | |
1071 | * | |
1072 | * They need to have the same vm_file, and the flags can only differ | |
1073 | * in things that mprotect may change. | |
1074 | * | |
1075 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
1076 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
1077 | * there is a vm_ops->close() function, because that indicates that the | |
1078 | * driver is doing some kind of reference counting. But that doesn't | |
1079 | * really matter for the anon_vma sharing case. | |
1080 | */ | |
1081 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
1082 | { | |
1083 | return a->vm_end == b->vm_start && | |
1084 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
1085 | a->vm_file == b->vm_file && | |
1086 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && | |
1087 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); | |
1088 | } | |
1089 | ||
1090 | /* | |
1091 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
1092 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
1093 | * the same as 'old', the other will be the new one that is trying | |
1094 | * to share the anon_vma. | |
1095 | * | |
1096 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
1097 | * the anon_vma of 'old' is concurrently in the process of being set up | |
1098 | * by another page fault trying to merge _that_. But that's ok: if it | |
1099 | * is being set up, that automatically means that it will be a singleton | |
1100 | * acceptable for merging, so we can do all of this optimistically. But | |
1101 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. | |
1102 | * | |
1103 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
1104 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
1105 | * is to return an anon_vma that is "complex" due to having gone through | |
1106 | * a fork). | |
1107 | * | |
1108 | * We also make sure that the two vma's are compatible (adjacent, | |
1109 | * and with the same memory policies). That's all stable, even with just | |
1110 | * a read lock on the mm_sem. | |
1111 | */ | |
1112 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
1113 | { | |
1114 | if (anon_vma_compatible(a, b)) { | |
1115 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); | |
1116 | ||
1117 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
1118 | return anon_vma; | |
1119 | } | |
1120 | return NULL; | |
1121 | } | |
1122 | ||
1da177e4 LT |
1123 | /* |
1124 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
1125 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
1126 | * to allocate a new anon_vma. It checks because a repetitive | |
1127 | * sequence of mprotects and faults may otherwise lead to distinct | |
1128 | * anon_vmas being allocated, preventing vma merge in subsequent | |
1129 | * mprotect. | |
1130 | */ | |
1131 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
1132 | { | |
d0e9fe17 | 1133 | struct anon_vma *anon_vma; |
1da177e4 | 1134 | struct vm_area_struct *near; |
1da177e4 LT |
1135 | |
1136 | near = vma->vm_next; | |
1137 | if (!near) | |
1138 | goto try_prev; | |
1139 | ||
d0e9fe17 LT |
1140 | anon_vma = reusable_anon_vma(near, vma, near); |
1141 | if (anon_vma) | |
1142 | return anon_vma; | |
1da177e4 | 1143 | try_prev: |
9be34c9d | 1144 | near = vma->vm_prev; |
1da177e4 LT |
1145 | if (!near) |
1146 | goto none; | |
1147 | ||
d0e9fe17 LT |
1148 | anon_vma = reusable_anon_vma(near, near, vma); |
1149 | if (anon_vma) | |
1150 | return anon_vma; | |
1da177e4 LT |
1151 | none: |
1152 | /* | |
1153 | * There's no absolute need to look only at touching neighbours: | |
1154 | * we could search further afield for "compatible" anon_vmas. | |
1155 | * But it would probably just be a waste of time searching, | |
1156 | * or lead to too many vmas hanging off the same anon_vma. | |
1157 | * We're trying to allow mprotect remerging later on, | |
1158 | * not trying to minimize memory used for anon_vmas. | |
1159 | */ | |
1160 | return NULL; | |
1161 | } | |
1162 | ||
1163 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 1164 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
1165 | struct file *file, long pages) |
1166 | { | |
1167 | const unsigned long stack_flags | |
1168 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
1169 | ||
44de9d0c HS |
1170 | mm->total_vm += pages; |
1171 | ||
1da177e4 LT |
1172 | if (file) { |
1173 | mm->shared_vm += pages; | |
1174 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
1175 | mm->exec_vm += pages; | |
1176 | } else if (flags & stack_flags) | |
1177 | mm->stack_vm += pages; | |
1da177e4 LT |
1178 | } |
1179 | #endif /* CONFIG_PROC_FS */ | |
1180 | ||
40401530 AV |
1181 | /* |
1182 | * If a hint addr is less than mmap_min_addr change hint to be as | |
1183 | * low as possible but still greater than mmap_min_addr | |
1184 | */ | |
1185 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
1186 | { | |
1187 | hint &= PAGE_MASK; | |
1188 | if (((void *)hint != NULL) && | |
1189 | (hint < mmap_min_addr)) | |
1190 | return PAGE_ALIGN(mmap_min_addr); | |
1191 | return hint; | |
1192 | } | |
1193 | ||
363ee17f DB |
1194 | static inline int mlock_future_check(struct mm_struct *mm, |
1195 | unsigned long flags, | |
1196 | unsigned long len) | |
1197 | { | |
1198 | unsigned long locked, lock_limit; | |
1199 | ||
1200 | /* mlock MCL_FUTURE? */ | |
1201 | if (flags & VM_LOCKED) { | |
1202 | locked = len >> PAGE_SHIFT; | |
1203 | locked += mm->locked_vm; | |
1204 | lock_limit = rlimit(RLIMIT_MEMLOCK); | |
1205 | lock_limit >>= PAGE_SHIFT; | |
1206 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) | |
1207 | return -EAGAIN; | |
1208 | } | |
1209 | return 0; | |
1210 | } | |
1211 | ||
1da177e4 | 1212 | /* |
27f5de79 | 1213 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
1214 | */ |
1215 | ||
e3fc629d | 1216 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 | 1217 | unsigned long len, unsigned long prot, |
bebeb3d6 | 1218 | unsigned long flags, unsigned long pgoff, |
41badc15 | 1219 | unsigned long *populate) |
1da177e4 LT |
1220 | { |
1221 | struct mm_struct * mm = current->mm; | |
ca16d140 | 1222 | vm_flags_t vm_flags; |
1da177e4 | 1223 | |
41badc15 | 1224 | *populate = 0; |
bebeb3d6 | 1225 | |
1da177e4 LT |
1226 | /* |
1227 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
1228 | * | |
1229 | * (the exception is when the underlying filesystem is noexec | |
1230 | * mounted, in which case we dont add PROT_EXEC.) | |
1231 | */ | |
1232 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 1233 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
1234 | prot |= PROT_EXEC; |
1235 | ||
1236 | if (!len) | |
1237 | return -EINVAL; | |
1238 | ||
7cd94146 EP |
1239 | if (!(flags & MAP_FIXED)) |
1240 | addr = round_hint_to_min(addr); | |
1241 | ||
1da177e4 LT |
1242 | /* Careful about overflows.. */ |
1243 | len = PAGE_ALIGN(len); | |
9206de95 | 1244 | if (!len) |
1da177e4 LT |
1245 | return -ENOMEM; |
1246 | ||
1247 | /* offset overflow? */ | |
1248 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
1249 | return -EOVERFLOW; | |
1250 | ||
1251 | /* Too many mappings? */ | |
1252 | if (mm->map_count > sysctl_max_map_count) | |
1253 | return -ENOMEM; | |
1254 | ||
1255 | /* Obtain the address to map to. we verify (or select) it and ensure | |
1256 | * that it represents a valid section of the address space. | |
1257 | */ | |
1258 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
1259 | if (addr & ~PAGE_MASK) | |
1260 | return addr; | |
1261 | ||
1262 | /* Do simple checking here so the lower-level routines won't have | |
1263 | * to. we assume access permissions have been handled by the open | |
1264 | * of the memory object, so we don't do any here. | |
1265 | */ | |
1266 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
1267 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
1268 | ||
cdf7b341 | 1269 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1270 | if (!can_do_mlock()) |
1271 | return -EPERM; | |
ba470de4 | 1272 | |
363ee17f DB |
1273 | if (mlock_future_check(mm, vm_flags, len)) |
1274 | return -EAGAIN; | |
1da177e4 | 1275 | |
1da177e4 | 1276 | if (file) { |
077bf22b ON |
1277 | struct inode *inode = file_inode(file); |
1278 | ||
1da177e4 LT |
1279 | switch (flags & MAP_TYPE) { |
1280 | case MAP_SHARED: | |
1281 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1282 | return -EACCES; | |
1283 | ||
1284 | /* | |
1285 | * Make sure we don't allow writing to an append-only | |
1286 | * file.. | |
1287 | */ | |
1288 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1289 | return -EACCES; | |
1290 | ||
1291 | /* | |
1292 | * Make sure there are no mandatory locks on the file. | |
1293 | */ | |
1294 | if (locks_verify_locked(inode)) | |
1295 | return -EAGAIN; | |
1296 | ||
1297 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1298 | if (!(file->f_mode & FMODE_WRITE)) | |
1299 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1300 | ||
1301 | /* fall through */ | |
1302 | case MAP_PRIVATE: | |
1303 | if (!(file->f_mode & FMODE_READ)) | |
1304 | return -EACCES; | |
d3ac7f89 | 1305 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1306 | if (vm_flags & VM_EXEC) |
1307 | return -EPERM; | |
1308 | vm_flags &= ~VM_MAYEXEC; | |
1309 | } | |
80c5606c | 1310 | |
72c2d531 | 1311 | if (!file->f_op->mmap) |
80c5606c | 1312 | return -ENODEV; |
b2c56e4f ON |
1313 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1314 | return -EINVAL; | |
1da177e4 LT |
1315 | break; |
1316 | ||
1317 | default: | |
1318 | return -EINVAL; | |
1319 | } | |
1320 | } else { | |
1321 | switch (flags & MAP_TYPE) { | |
1322 | case MAP_SHARED: | |
b2c56e4f ON |
1323 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1324 | return -EINVAL; | |
ce363942 TH |
1325 | /* |
1326 | * Ignore pgoff. | |
1327 | */ | |
1328 | pgoff = 0; | |
1da177e4 LT |
1329 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1330 | break; | |
1331 | case MAP_PRIVATE: | |
1332 | /* | |
1333 | * Set pgoff according to addr for anon_vma. | |
1334 | */ | |
1335 | pgoff = addr >> PAGE_SHIFT; | |
1336 | break; | |
1337 | default: | |
1338 | return -EINVAL; | |
1339 | } | |
1340 | } | |
1341 | ||
c22c0d63 ML |
1342 | /* |
1343 | * Set 'VM_NORESERVE' if we should not account for the | |
1344 | * memory use of this mapping. | |
1345 | */ | |
1346 | if (flags & MAP_NORESERVE) { | |
1347 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1348 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1349 | vm_flags |= VM_NORESERVE; | |
1350 | ||
1351 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1352 | if (file && is_file_hugepages(file)) | |
1353 | vm_flags |= VM_NORESERVE; | |
1354 | } | |
1355 | ||
1356 | addr = mmap_region(file, addr, len, vm_flags, pgoff); | |
09a9f1d2 ML |
1357 | if (!IS_ERR_VALUE(addr) && |
1358 | ((vm_flags & VM_LOCKED) || | |
1359 | (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) | |
41badc15 | 1360 | *populate = len; |
bebeb3d6 | 1361 | return addr; |
0165ab44 | 1362 | } |
6be5ceb0 | 1363 | |
66f0dc48 HD |
1364 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1365 | unsigned long, prot, unsigned long, flags, | |
1366 | unsigned long, fd, unsigned long, pgoff) | |
1367 | { | |
1368 | struct file *file = NULL; | |
1369 | unsigned long retval = -EBADF; | |
1370 | ||
1371 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1372 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1373 | file = fget(fd); |
1374 | if (!file) | |
1375 | goto out; | |
af73e4d9 NH |
1376 | if (is_file_hugepages(file)) |
1377 | len = ALIGN(len, huge_page_size(hstate_file(file))); | |
493af578 JE |
1378 | retval = -EINVAL; |
1379 | if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) | |
1380 | goto out_fput; | |
66f0dc48 HD |
1381 | } else if (flags & MAP_HUGETLB) { |
1382 | struct user_struct *user = NULL; | |
c103a4dc | 1383 | struct hstate *hs; |
af73e4d9 | 1384 | |
c103a4dc | 1385 | hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK); |
091d0d55 LZ |
1386 | if (!hs) |
1387 | return -EINVAL; | |
1388 | ||
1389 | len = ALIGN(len, huge_page_size(hs)); | |
66f0dc48 HD |
1390 | /* |
1391 | * VM_NORESERVE is used because the reservations will be | |
1392 | * taken when vm_ops->mmap() is called | |
1393 | * A dummy user value is used because we are not locking | |
1394 | * memory so no accounting is necessary | |
1395 | */ | |
af73e4d9 | 1396 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, |
42d7395f AK |
1397 | VM_NORESERVE, |
1398 | &user, HUGETLB_ANONHUGE_INODE, | |
1399 | (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); | |
66f0dc48 HD |
1400 | if (IS_ERR(file)) |
1401 | return PTR_ERR(file); | |
1402 | } | |
1403 | ||
1404 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1405 | ||
eb36c587 | 1406 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
493af578 | 1407 | out_fput: |
66f0dc48 HD |
1408 | if (file) |
1409 | fput(file); | |
1410 | out: | |
1411 | return retval; | |
1412 | } | |
1413 | ||
a4679373 CH |
1414 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1415 | struct mmap_arg_struct { | |
1416 | unsigned long addr; | |
1417 | unsigned long len; | |
1418 | unsigned long prot; | |
1419 | unsigned long flags; | |
1420 | unsigned long fd; | |
1421 | unsigned long offset; | |
1422 | }; | |
1423 | ||
1424 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1425 | { | |
1426 | struct mmap_arg_struct a; | |
1427 | ||
1428 | if (copy_from_user(&a, arg, sizeof(a))) | |
1429 | return -EFAULT; | |
1430 | if (a.offset & ~PAGE_MASK) | |
1431 | return -EINVAL; | |
1432 | ||
1433 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1434 | a.offset >> PAGE_SHIFT); | |
1435 | } | |
1436 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1437 | ||
4e950f6f AD |
1438 | /* |
1439 | * Some shared mappigns will want the pages marked read-only | |
1440 | * to track write events. If so, we'll downgrade vm_page_prot | |
1441 | * to the private version (using protection_map[] without the | |
1442 | * VM_SHARED bit). | |
1443 | */ | |
1444 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1445 | { | |
ca16d140 | 1446 | vm_flags_t vm_flags = vma->vm_flags; |
4e950f6f AD |
1447 | |
1448 | /* If it was private or non-writable, the write bit is already clear */ | |
1449 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1450 | return 0; | |
1451 | ||
1452 | /* The backer wishes to know when pages are first written to? */ | |
1453 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1454 | return 1; | |
1455 | ||
1456 | /* The open routine did something to the protections already? */ | |
1457 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1458 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1459 | return 0; |
1460 | ||
1461 | /* Specialty mapping? */ | |
4b6e1e37 | 1462 | if (vm_flags & VM_PFNMAP) |
4e950f6f AD |
1463 | return 0; |
1464 | ||
1465 | /* Can the mapping track the dirty pages? */ | |
1466 | return vma->vm_file && vma->vm_file->f_mapping && | |
1467 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1468 | } | |
1469 | ||
fc8744ad LT |
1470 | /* |
1471 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1472 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1473 | */ |
ca16d140 | 1474 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1475 | { |
5a6fe125 MG |
1476 | /* |
1477 | * hugetlb has its own accounting separate from the core VM | |
1478 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1479 | */ | |
1480 | if (file && is_file_hugepages(file)) | |
1481 | return 0; | |
1482 | ||
fc8744ad LT |
1483 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1484 | } | |
1485 | ||
0165ab44 | 1486 | unsigned long mmap_region(struct file *file, unsigned long addr, |
c22c0d63 | 1487 | unsigned long len, vm_flags_t vm_flags, unsigned long pgoff) |
0165ab44 MS |
1488 | { |
1489 | struct mm_struct *mm = current->mm; | |
1490 | struct vm_area_struct *vma, *prev; | |
0165ab44 MS |
1491 | int error; |
1492 | struct rb_node **rb_link, *rb_parent; | |
1493 | unsigned long charged = 0; | |
0165ab44 | 1494 | |
e8420a8e CH |
1495 | /* Check against address space limit. */ |
1496 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) { | |
1497 | unsigned long nr_pages; | |
1498 | ||
1499 | /* | |
1500 | * MAP_FIXED may remove pages of mappings that intersects with | |
1501 | * requested mapping. Account for the pages it would unmap. | |
1502 | */ | |
1503 | if (!(vm_flags & MAP_FIXED)) | |
1504 | return -ENOMEM; | |
1505 | ||
1506 | nr_pages = count_vma_pages_range(mm, addr, addr + len); | |
1507 | ||
1508 | if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages)) | |
1509 | return -ENOMEM; | |
1510 | } | |
1511 | ||
1da177e4 LT |
1512 | /* Clear old maps */ |
1513 | error = -ENOMEM; | |
1514 | munmap_back: | |
6597d783 | 1515 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
1516 | if (do_munmap(mm, addr, len)) |
1517 | return -ENOMEM; | |
1518 | goto munmap_back; | |
1519 | } | |
1520 | ||
fc8744ad LT |
1521 | /* |
1522 | * Private writable mapping: check memory availability | |
1523 | */ | |
5a6fe125 | 1524 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1525 | charged = len >> PAGE_SHIFT; |
191c5424 | 1526 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1527 | return -ENOMEM; |
1528 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1529 | } |
1530 | ||
1531 | /* | |
de33c8db | 1532 | * Can we just expand an old mapping? |
1da177e4 | 1533 | */ |
de33c8db LT |
1534 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1535 | if (vma) | |
1536 | goto out; | |
1da177e4 LT |
1537 | |
1538 | /* | |
1539 | * Determine the object being mapped and call the appropriate | |
1540 | * specific mapper. the address has already been validated, but | |
1541 | * not unmapped, but the maps are removed from the list. | |
1542 | */ | |
c5e3b83e | 1543 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1544 | if (!vma) { |
1545 | error = -ENOMEM; | |
1546 | goto unacct_error; | |
1547 | } | |
1da177e4 LT |
1548 | |
1549 | vma->vm_mm = mm; | |
1550 | vma->vm_start = addr; | |
1551 | vma->vm_end = addr + len; | |
1552 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1553 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1554 | vma->vm_pgoff = pgoff; |
5beb4930 | 1555 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
1556 | |
1557 | if (file) { | |
1da177e4 LT |
1558 | if (vm_flags & VM_DENYWRITE) { |
1559 | error = deny_write_access(file); | |
1560 | if (error) | |
1561 | goto free_vma; | |
1da177e4 | 1562 | } |
cb0942b8 | 1563 | vma->vm_file = get_file(file); |
1da177e4 LT |
1564 | error = file->f_op->mmap(file, vma); |
1565 | if (error) | |
1566 | goto unmap_and_free_vma; | |
f8dbf0a7 HS |
1567 | |
1568 | /* Can addr have changed?? | |
1569 | * | |
1570 | * Answer: Yes, several device drivers can do it in their | |
1571 | * f_op->mmap method. -DaveM | |
2897b4d2 JK |
1572 | * Bug: If addr is changed, prev, rb_link, rb_parent should |
1573 | * be updated for vma_link() | |
f8dbf0a7 | 1574 | */ |
2897b4d2 JK |
1575 | WARN_ON_ONCE(addr != vma->vm_start); |
1576 | ||
f8dbf0a7 | 1577 | addr = vma->vm_start; |
f8dbf0a7 | 1578 | vm_flags = vma->vm_flags; |
1da177e4 LT |
1579 | } else if (vm_flags & VM_SHARED) { |
1580 | error = shmem_zero_setup(vma); | |
1581 | if (error) | |
1582 | goto free_vma; | |
1583 | } | |
1584 | ||
c9d0bf24 MD |
1585 | if (vma_wants_writenotify(vma)) { |
1586 | pgprot_t pprot = vma->vm_page_prot; | |
1587 | ||
1588 | /* Can vma->vm_page_prot have changed?? | |
1589 | * | |
1590 | * Answer: Yes, drivers may have changed it in their | |
1591 | * f_op->mmap method. | |
1592 | * | |
1593 | * Ensures that vmas marked as uncached stay that way. | |
1594 | */ | |
1ddd439e | 1595 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
c9d0bf24 MD |
1596 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
1597 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
1598 | } | |
d08b3851 | 1599 | |
de33c8db | 1600 | vma_link(mm, vma, prev, rb_link, rb_parent); |
4d3d5b41 | 1601 | /* Once vma denies write, undo our temporary denial count */ |
e8686772 ON |
1602 | if (vm_flags & VM_DENYWRITE) |
1603 | allow_write_access(file); | |
1604 | file = vma->vm_file; | |
4d3d5b41 | 1605 | out: |
cdd6c482 | 1606 | perf_event_mmap(vma); |
0a4a9391 | 1607 | |
ab50b8ed | 1608 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1609 | if (vm_flags & VM_LOCKED) { |
bebeb3d6 ML |
1610 | if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || |
1611 | vma == get_gate_vma(current->mm))) | |
06f9d8c2 | 1612 | mm->locked_vm += (len >> PAGE_SHIFT); |
bebeb3d6 ML |
1613 | else |
1614 | vma->vm_flags &= ~VM_LOCKED; | |
1615 | } | |
2b144498 | 1616 | |
c7a3a88c ON |
1617 | if (file) |
1618 | uprobe_mmap(vma); | |
2b144498 | 1619 | |
d9104d1c CG |
1620 | /* |
1621 | * New (or expanded) vma always get soft dirty status. | |
1622 | * Otherwise user-space soft-dirty page tracker won't | |
1623 | * be able to distinguish situation when vma area unmapped, | |
1624 | * then new mapped in-place (which must be aimed as | |
1625 | * a completely new data area). | |
1626 | */ | |
1627 | vma->vm_flags |= VM_SOFTDIRTY; | |
1628 | ||
1da177e4 LT |
1629 | return addr; |
1630 | ||
1631 | unmap_and_free_vma: | |
e8686772 ON |
1632 | if (vm_flags & VM_DENYWRITE) |
1633 | allow_write_access(file); | |
1da177e4 LT |
1634 | vma->vm_file = NULL; |
1635 | fput(file); | |
1636 | ||
1637 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1638 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1639 | charged = 0; | |
1da177e4 LT |
1640 | free_vma: |
1641 | kmem_cache_free(vm_area_cachep, vma); | |
1642 | unacct_error: | |
1643 | if (charged) | |
1644 | vm_unacct_memory(charged); | |
1645 | return error; | |
1646 | } | |
1647 | ||
db4fbfb9 ML |
1648 | unsigned long unmapped_area(struct vm_unmapped_area_info *info) |
1649 | { | |
1650 | /* | |
1651 | * We implement the search by looking for an rbtree node that | |
1652 | * immediately follows a suitable gap. That is, | |
1653 | * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; | |
1654 | * - gap_end = vma->vm_start >= info->low_limit + length; | |
1655 | * - gap_end - gap_start >= length | |
1656 | */ | |
1657 | ||
1658 | struct mm_struct *mm = current->mm; | |
1659 | struct vm_area_struct *vma; | |
1660 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1661 | ||
1662 | /* Adjust search length to account for worst case alignment overhead */ | |
1663 | length = info->length + info->align_mask; | |
1664 | if (length < info->length) | |
1665 | return -ENOMEM; | |
1666 | ||
1667 | /* Adjust search limits by the desired length */ | |
1668 | if (info->high_limit < length) | |
1669 | return -ENOMEM; | |
1670 | high_limit = info->high_limit - length; | |
1671 | ||
1672 | if (info->low_limit > high_limit) | |
1673 | return -ENOMEM; | |
1674 | low_limit = info->low_limit + length; | |
1675 | ||
1676 | /* Check if rbtree root looks promising */ | |
1677 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1678 | goto check_highest; | |
1679 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1680 | if (vma->rb_subtree_gap < length) | |
1681 | goto check_highest; | |
1682 | ||
1683 | while (true) { | |
1684 | /* Visit left subtree if it looks promising */ | |
1685 | gap_end = vma->vm_start; | |
1686 | if (gap_end >= low_limit && vma->vm_rb.rb_left) { | |
1687 | struct vm_area_struct *left = | |
1688 | rb_entry(vma->vm_rb.rb_left, | |
1689 | struct vm_area_struct, vm_rb); | |
1690 | if (left->rb_subtree_gap >= length) { | |
1691 | vma = left; | |
1692 | continue; | |
1693 | } | |
1694 | } | |
1695 | ||
1696 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; | |
1697 | check_current: | |
1698 | /* Check if current node has a suitable gap */ | |
1699 | if (gap_start > high_limit) | |
1700 | return -ENOMEM; | |
1701 | if (gap_end >= low_limit && gap_end - gap_start >= length) | |
1702 | goto found; | |
1703 | ||
1704 | /* Visit right subtree if it looks promising */ | |
1705 | if (vma->vm_rb.rb_right) { | |
1706 | struct vm_area_struct *right = | |
1707 | rb_entry(vma->vm_rb.rb_right, | |
1708 | struct vm_area_struct, vm_rb); | |
1709 | if (right->rb_subtree_gap >= length) { | |
1710 | vma = right; | |
1711 | continue; | |
1712 | } | |
1713 | } | |
1714 | ||
1715 | /* Go back up the rbtree to find next candidate node */ | |
1716 | while (true) { | |
1717 | struct rb_node *prev = &vma->vm_rb; | |
1718 | if (!rb_parent(prev)) | |
1719 | goto check_highest; | |
1720 | vma = rb_entry(rb_parent(prev), | |
1721 | struct vm_area_struct, vm_rb); | |
1722 | if (prev == vma->vm_rb.rb_left) { | |
1723 | gap_start = vma->vm_prev->vm_end; | |
1724 | gap_end = vma->vm_start; | |
1725 | goto check_current; | |
1726 | } | |
1727 | } | |
1728 | } | |
1729 | ||
1730 | check_highest: | |
1731 | /* Check highest gap, which does not precede any rbtree node */ | |
1732 | gap_start = mm->highest_vm_end; | |
1733 | gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ | |
1734 | if (gap_start > high_limit) | |
1735 | return -ENOMEM; | |
1736 | ||
1737 | found: | |
1738 | /* We found a suitable gap. Clip it with the original low_limit. */ | |
1739 | if (gap_start < info->low_limit) | |
1740 | gap_start = info->low_limit; | |
1741 | ||
1742 | /* Adjust gap address to the desired alignment */ | |
1743 | gap_start += (info->align_offset - gap_start) & info->align_mask; | |
1744 | ||
1745 | VM_BUG_ON(gap_start + info->length > info->high_limit); | |
1746 | VM_BUG_ON(gap_start + info->length > gap_end); | |
1747 | return gap_start; | |
1748 | } | |
1749 | ||
1750 | unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) | |
1751 | { | |
1752 | struct mm_struct *mm = current->mm; | |
1753 | struct vm_area_struct *vma; | |
1754 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1755 | ||
1756 | /* Adjust search length to account for worst case alignment overhead */ | |
1757 | length = info->length + info->align_mask; | |
1758 | if (length < info->length) | |
1759 | return -ENOMEM; | |
1760 | ||
1761 | /* | |
1762 | * Adjust search limits by the desired length. | |
1763 | * See implementation comment at top of unmapped_area(). | |
1764 | */ | |
1765 | gap_end = info->high_limit; | |
1766 | if (gap_end < length) | |
1767 | return -ENOMEM; | |
1768 | high_limit = gap_end - length; | |
1769 | ||
1770 | if (info->low_limit > high_limit) | |
1771 | return -ENOMEM; | |
1772 | low_limit = info->low_limit + length; | |
1773 | ||
1774 | /* Check highest gap, which does not precede any rbtree node */ | |
1775 | gap_start = mm->highest_vm_end; | |
1776 | if (gap_start <= high_limit) | |
1777 | goto found_highest; | |
1778 | ||
1779 | /* Check if rbtree root looks promising */ | |
1780 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1781 | return -ENOMEM; | |
1782 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1783 | if (vma->rb_subtree_gap < length) | |
1784 | return -ENOMEM; | |
1785 | ||
1786 | while (true) { | |
1787 | /* Visit right subtree if it looks promising */ | |
1788 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; | |
1789 | if (gap_start <= high_limit && vma->vm_rb.rb_right) { | |
1790 | struct vm_area_struct *right = | |
1791 | rb_entry(vma->vm_rb.rb_right, | |
1792 | struct vm_area_struct, vm_rb); | |
1793 | if (right->rb_subtree_gap >= length) { | |
1794 | vma = right; | |
1795 | continue; | |
1796 | } | |
1797 | } | |
1798 | ||
1799 | check_current: | |
1800 | /* Check if current node has a suitable gap */ | |
1801 | gap_end = vma->vm_start; | |
1802 | if (gap_end < low_limit) | |
1803 | return -ENOMEM; | |
1804 | if (gap_start <= high_limit && gap_end - gap_start >= length) | |
1805 | goto found; | |
1806 | ||
1807 | /* Visit left subtree if it looks promising */ | |
1808 | if (vma->vm_rb.rb_left) { | |
1809 | struct vm_area_struct *left = | |
1810 | rb_entry(vma->vm_rb.rb_left, | |
1811 | struct vm_area_struct, vm_rb); | |
1812 | if (left->rb_subtree_gap >= length) { | |
1813 | vma = left; | |
1814 | continue; | |
1815 | } | |
1816 | } | |
1817 | ||
1818 | /* Go back up the rbtree to find next candidate node */ | |
1819 | while (true) { | |
1820 | struct rb_node *prev = &vma->vm_rb; | |
1821 | if (!rb_parent(prev)) | |
1822 | return -ENOMEM; | |
1823 | vma = rb_entry(rb_parent(prev), | |
1824 | struct vm_area_struct, vm_rb); | |
1825 | if (prev == vma->vm_rb.rb_right) { | |
1826 | gap_start = vma->vm_prev ? | |
1827 | vma->vm_prev->vm_end : 0; | |
1828 | goto check_current; | |
1829 | } | |
1830 | } | |
1831 | } | |
1832 | ||
1833 | found: | |
1834 | /* We found a suitable gap. Clip it with the original high_limit. */ | |
1835 | if (gap_end > info->high_limit) | |
1836 | gap_end = info->high_limit; | |
1837 | ||
1838 | found_highest: | |
1839 | /* Compute highest gap address at the desired alignment */ | |
1840 | gap_end -= info->length; | |
1841 | gap_end -= (gap_end - info->align_offset) & info->align_mask; | |
1842 | ||
1843 | VM_BUG_ON(gap_end < info->low_limit); | |
1844 | VM_BUG_ON(gap_end < gap_start); | |
1845 | return gap_end; | |
1846 | } | |
1847 | ||
1da177e4 LT |
1848 | /* Get an address range which is currently unmapped. |
1849 | * For shmat() with addr=0. | |
1850 | * | |
1851 | * Ugly calling convention alert: | |
1852 | * Return value with the low bits set means error value, | |
1853 | * ie | |
1854 | * if (ret & ~PAGE_MASK) | |
1855 | * error = ret; | |
1856 | * | |
1857 | * This function "knows" that -ENOMEM has the bits set. | |
1858 | */ | |
1859 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1860 | unsigned long | |
1861 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1862 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1863 | { | |
1864 | struct mm_struct *mm = current->mm; | |
1865 | struct vm_area_struct *vma; | |
db4fbfb9 | 1866 | struct vm_unmapped_area_info info; |
1da177e4 | 1867 | |
2afc745f | 1868 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
1869 | return -ENOMEM; |
1870 | ||
06abdfb4 BH |
1871 | if (flags & MAP_FIXED) |
1872 | return addr; | |
1873 | ||
1da177e4 LT |
1874 | if (addr) { |
1875 | addr = PAGE_ALIGN(addr); | |
1876 | vma = find_vma(mm, addr); | |
2afc745f | 1877 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1da177e4 LT |
1878 | (!vma || addr + len <= vma->vm_start)) |
1879 | return addr; | |
1880 | } | |
1da177e4 | 1881 | |
db4fbfb9 ML |
1882 | info.flags = 0; |
1883 | info.length = len; | |
4e99b021 | 1884 | info.low_limit = mm->mmap_base; |
db4fbfb9 ML |
1885 | info.high_limit = TASK_SIZE; |
1886 | info.align_mask = 0; | |
1887 | return vm_unmapped_area(&info); | |
1da177e4 LT |
1888 | } |
1889 | #endif | |
1890 | ||
1da177e4 LT |
1891 | /* |
1892 | * This mmap-allocator allocates new areas top-down from below the | |
1893 | * stack's low limit (the base): | |
1894 | */ | |
1895 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1896 | unsigned long | |
1897 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1898 | const unsigned long len, const unsigned long pgoff, | |
1899 | const unsigned long flags) | |
1900 | { | |
1901 | struct vm_area_struct *vma; | |
1902 | struct mm_struct *mm = current->mm; | |
db4fbfb9 ML |
1903 | unsigned long addr = addr0; |
1904 | struct vm_unmapped_area_info info; | |
1da177e4 LT |
1905 | |
1906 | /* requested length too big for entire address space */ | |
2afc745f | 1907 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
1908 | return -ENOMEM; |
1909 | ||
06abdfb4 BH |
1910 | if (flags & MAP_FIXED) |
1911 | return addr; | |
1912 | ||
1da177e4 LT |
1913 | /* requesting a specific address */ |
1914 | if (addr) { | |
1915 | addr = PAGE_ALIGN(addr); | |
1916 | vma = find_vma(mm, addr); | |
2afc745f | 1917 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1da177e4 LT |
1918 | (!vma || addr + len <= vma->vm_start)) |
1919 | return addr; | |
1920 | } | |
1921 | ||
db4fbfb9 ML |
1922 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
1923 | info.length = len; | |
2afc745f | 1924 | info.low_limit = max(PAGE_SIZE, mmap_min_addr); |
db4fbfb9 ML |
1925 | info.high_limit = mm->mmap_base; |
1926 | info.align_mask = 0; | |
1927 | addr = vm_unmapped_area(&info); | |
b716ad95 | 1928 | |
1da177e4 LT |
1929 | /* |
1930 | * A failed mmap() very likely causes application failure, | |
1931 | * so fall back to the bottom-up function here. This scenario | |
1932 | * can happen with large stack limits and large mmap() | |
1933 | * allocations. | |
1934 | */ | |
db4fbfb9 ML |
1935 | if (addr & ~PAGE_MASK) { |
1936 | VM_BUG_ON(addr != -ENOMEM); | |
1937 | info.flags = 0; | |
1938 | info.low_limit = TASK_UNMAPPED_BASE; | |
1939 | info.high_limit = TASK_SIZE; | |
1940 | addr = vm_unmapped_area(&info); | |
1941 | } | |
1da177e4 LT |
1942 | |
1943 | return addr; | |
1944 | } | |
1945 | #endif | |
1946 | ||
1da177e4 LT |
1947 | unsigned long |
1948 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1949 | unsigned long pgoff, unsigned long flags) | |
1950 | { | |
06abdfb4 BH |
1951 | unsigned long (*get_area)(struct file *, unsigned long, |
1952 | unsigned long, unsigned long, unsigned long); | |
1953 | ||
9206de95 AV |
1954 | unsigned long error = arch_mmap_check(addr, len, flags); |
1955 | if (error) | |
1956 | return error; | |
1957 | ||
1958 | /* Careful about overflows.. */ | |
1959 | if (len > TASK_SIZE) | |
1960 | return -ENOMEM; | |
1961 | ||
06abdfb4 | 1962 | get_area = current->mm->get_unmapped_area; |
72c2d531 | 1963 | if (file && file->f_op->get_unmapped_area) |
06abdfb4 BH |
1964 | get_area = file->f_op->get_unmapped_area; |
1965 | addr = get_area(file, addr, len, pgoff, flags); | |
1966 | if (IS_ERR_VALUE(addr)) | |
1967 | return addr; | |
1da177e4 | 1968 | |
07ab67c8 LT |
1969 | if (addr > TASK_SIZE - len) |
1970 | return -ENOMEM; | |
1971 | if (addr & ~PAGE_MASK) | |
1972 | return -EINVAL; | |
06abdfb4 | 1973 | |
9ac4ed4b AV |
1974 | addr = arch_rebalance_pgtables(addr, len); |
1975 | error = security_mmap_addr(addr); | |
1976 | return error ? error : addr; | |
1da177e4 LT |
1977 | } |
1978 | ||
1979 | EXPORT_SYMBOL(get_unmapped_area); | |
1980 | ||
1981 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1982 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1983 | { |
1984 | struct vm_area_struct *vma = NULL; | |
1985 | ||
841e31e5 RM |
1986 | /* Check the cache first. */ |
1987 | /* (Cache hit rate is typically around 35%.) */ | |
b6a9b7f6 | 1988 | vma = ACCESS_ONCE(mm->mmap_cache); |
841e31e5 RM |
1989 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { |
1990 | struct rb_node *rb_node; | |
1991 | ||
1992 | rb_node = mm->mm_rb.rb_node; | |
1993 | vma = NULL; | |
1994 | ||
1995 | while (rb_node) { | |
1996 | struct vm_area_struct *vma_tmp; | |
1997 | ||
1998 | vma_tmp = rb_entry(rb_node, | |
1999 | struct vm_area_struct, vm_rb); | |
2000 | ||
2001 | if (vma_tmp->vm_end > addr) { | |
2002 | vma = vma_tmp; | |
2003 | if (vma_tmp->vm_start <= addr) | |
2004 | break; | |
2005 | rb_node = rb_node->rb_left; | |
2006 | } else | |
2007 | rb_node = rb_node->rb_right; | |
1da177e4 | 2008 | } |
841e31e5 RM |
2009 | if (vma) |
2010 | mm->mmap_cache = vma; | |
1da177e4 LT |
2011 | } |
2012 | return vma; | |
2013 | } | |
2014 | ||
2015 | EXPORT_SYMBOL(find_vma); | |
2016 | ||
6bd4837d KM |
2017 | /* |
2018 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 2019 | */ |
1da177e4 LT |
2020 | struct vm_area_struct * |
2021 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
2022 | struct vm_area_struct **pprev) | |
2023 | { | |
6bd4837d | 2024 | struct vm_area_struct *vma; |
1da177e4 | 2025 | |
6bd4837d | 2026 | vma = find_vma(mm, addr); |
83cd904d MP |
2027 | if (vma) { |
2028 | *pprev = vma->vm_prev; | |
2029 | } else { | |
2030 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
2031 | *pprev = NULL; | |
2032 | while (rb_node) { | |
2033 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
2034 | rb_node = rb_node->rb_right; | |
2035 | } | |
2036 | } | |
6bd4837d | 2037 | return vma; |
1da177e4 LT |
2038 | } |
2039 | ||
2040 | /* | |
2041 | * Verify that the stack growth is acceptable and | |
2042 | * update accounting. This is shared with both the | |
2043 | * grow-up and grow-down cases. | |
2044 | */ | |
48aae425 | 2045 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
2046 | { |
2047 | struct mm_struct *mm = vma->vm_mm; | |
2048 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 2049 | unsigned long new_start; |
1da177e4 LT |
2050 | |
2051 | /* address space limit tests */ | |
119f657c | 2052 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
2053 | return -ENOMEM; |
2054 | ||
2055 | /* Stack limit test */ | |
59e99e5b | 2056 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
1da177e4 LT |
2057 | return -ENOMEM; |
2058 | ||
2059 | /* mlock limit tests */ | |
2060 | if (vma->vm_flags & VM_LOCKED) { | |
2061 | unsigned long locked; | |
2062 | unsigned long limit; | |
2063 | locked = mm->locked_vm + grow; | |
59e99e5b JS |
2064 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
2065 | limit >>= PAGE_SHIFT; | |
1da177e4 LT |
2066 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
2067 | return -ENOMEM; | |
2068 | } | |
2069 | ||
0d59a01b AL |
2070 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
2071 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
2072 | vma->vm_end - size; | |
2073 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
2074 | return -EFAULT; | |
2075 | ||
1da177e4 LT |
2076 | /* |
2077 | * Overcommit.. This must be the final test, as it will | |
2078 | * update security statistics. | |
2079 | */ | |
05fa199d | 2080 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
2081 | return -ENOMEM; |
2082 | ||
2083 | /* Ok, everything looks good - let it rip */ | |
1da177e4 LT |
2084 | if (vma->vm_flags & VM_LOCKED) |
2085 | mm->locked_vm += grow; | |
ab50b8ed | 2086 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
2087 | return 0; |
2088 | } | |
2089 | ||
46dea3d0 | 2090 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 2091 | /* |
46dea3d0 HD |
2092 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
2093 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 2094 | */ |
46dea3d0 | 2095 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 LT |
2096 | { |
2097 | int error; | |
2098 | ||
2099 | if (!(vma->vm_flags & VM_GROWSUP)) | |
2100 | return -EFAULT; | |
2101 | ||
2102 | /* | |
2103 | * We must make sure the anon_vma is allocated | |
2104 | * so that the anon_vma locking is not a noop. | |
2105 | */ | |
2106 | if (unlikely(anon_vma_prepare(vma))) | |
2107 | return -ENOMEM; | |
bb4a340e | 2108 | vma_lock_anon_vma(vma); |
1da177e4 LT |
2109 | |
2110 | /* | |
2111 | * vma->vm_start/vm_end cannot change under us because the caller | |
2112 | * is required to hold the mmap_sem in read mode. We need the | |
2113 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 2114 | * Also guard against wrapping around to address 0. |
1da177e4 | 2115 | */ |
06b32f3a HD |
2116 | if (address < PAGE_ALIGN(address+4)) |
2117 | address = PAGE_ALIGN(address+4); | |
2118 | else { | |
bb4a340e | 2119 | vma_unlock_anon_vma(vma); |
06b32f3a HD |
2120 | return -ENOMEM; |
2121 | } | |
1da177e4 LT |
2122 | error = 0; |
2123 | ||
2124 | /* Somebody else might have raced and expanded it already */ | |
2125 | if (address > vma->vm_end) { | |
2126 | unsigned long size, grow; | |
2127 | ||
2128 | size = address - vma->vm_start; | |
2129 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
2130 | ||
42c36f63 HD |
2131 | error = -ENOMEM; |
2132 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
2133 | error = acct_stack_growth(vma, size, grow); | |
2134 | if (!error) { | |
4128997b ML |
2135 | /* |
2136 | * vma_gap_update() doesn't support concurrent | |
2137 | * updates, but we only hold a shared mmap_sem | |
2138 | * lock here, so we need to protect against | |
2139 | * concurrent vma expansions. | |
2140 | * vma_lock_anon_vma() doesn't help here, as | |
2141 | * we don't guarantee that all growable vmas | |
2142 | * in a mm share the same root anon vma. | |
2143 | * So, we reuse mm->page_table_lock to guard | |
2144 | * against concurrent vma expansions. | |
2145 | */ | |
2146 | spin_lock(&vma->vm_mm->page_table_lock); | |
bf181b9f | 2147 | anon_vma_interval_tree_pre_update_vma(vma); |
42c36f63 | 2148 | vma->vm_end = address; |
bf181b9f | 2149 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 ML |
2150 | if (vma->vm_next) |
2151 | vma_gap_update(vma->vm_next); | |
2152 | else | |
2153 | vma->vm_mm->highest_vm_end = address; | |
4128997b ML |
2154 | spin_unlock(&vma->vm_mm->page_table_lock); |
2155 | ||
42c36f63 HD |
2156 | perf_event_mmap(vma); |
2157 | } | |
3af9e859 | 2158 | } |
1da177e4 | 2159 | } |
bb4a340e | 2160 | vma_unlock_anon_vma(vma); |
b15d00b6 | 2161 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 2162 | validate_mm(vma->vm_mm); |
1da177e4 LT |
2163 | return error; |
2164 | } | |
46dea3d0 HD |
2165 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
2166 | ||
1da177e4 LT |
2167 | /* |
2168 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
2169 | */ | |
d05f3169 | 2170 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 2171 | unsigned long address) |
1da177e4 LT |
2172 | { |
2173 | int error; | |
2174 | ||
2175 | /* | |
2176 | * We must make sure the anon_vma is allocated | |
2177 | * so that the anon_vma locking is not a noop. | |
2178 | */ | |
2179 | if (unlikely(anon_vma_prepare(vma))) | |
2180 | return -ENOMEM; | |
8869477a EP |
2181 | |
2182 | address &= PAGE_MASK; | |
e5467859 | 2183 | error = security_mmap_addr(address); |
8869477a EP |
2184 | if (error) |
2185 | return error; | |
2186 | ||
bb4a340e | 2187 | vma_lock_anon_vma(vma); |
1da177e4 LT |
2188 | |
2189 | /* | |
2190 | * vma->vm_start/vm_end cannot change under us because the caller | |
2191 | * is required to hold the mmap_sem in read mode. We need the | |
2192 | * anon_vma lock to serialize against concurrent expand_stacks. | |
2193 | */ | |
1da177e4 LT |
2194 | |
2195 | /* Somebody else might have raced and expanded it already */ | |
2196 | if (address < vma->vm_start) { | |
2197 | unsigned long size, grow; | |
2198 | ||
2199 | size = vma->vm_end - address; | |
2200 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
2201 | ||
a626ca6a LT |
2202 | error = -ENOMEM; |
2203 | if (grow <= vma->vm_pgoff) { | |
2204 | error = acct_stack_growth(vma, size, grow); | |
2205 | if (!error) { | |
4128997b ML |
2206 | /* |
2207 | * vma_gap_update() doesn't support concurrent | |
2208 | * updates, but we only hold a shared mmap_sem | |
2209 | * lock here, so we need to protect against | |
2210 | * concurrent vma expansions. | |
2211 | * vma_lock_anon_vma() doesn't help here, as | |
2212 | * we don't guarantee that all growable vmas | |
2213 | * in a mm share the same root anon vma. | |
2214 | * So, we reuse mm->page_table_lock to guard | |
2215 | * against concurrent vma expansions. | |
2216 | */ | |
2217 | spin_lock(&vma->vm_mm->page_table_lock); | |
bf181b9f | 2218 | anon_vma_interval_tree_pre_update_vma(vma); |
a626ca6a LT |
2219 | vma->vm_start = address; |
2220 | vma->vm_pgoff -= grow; | |
bf181b9f | 2221 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 | 2222 | vma_gap_update(vma); |
4128997b ML |
2223 | spin_unlock(&vma->vm_mm->page_table_lock); |
2224 | ||
a626ca6a LT |
2225 | perf_event_mmap(vma); |
2226 | } | |
1da177e4 LT |
2227 | } |
2228 | } | |
bb4a340e | 2229 | vma_unlock_anon_vma(vma); |
b15d00b6 | 2230 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 2231 | validate_mm(vma->vm_mm); |
1da177e4 LT |
2232 | return error; |
2233 | } | |
2234 | ||
09884964 LT |
2235 | /* |
2236 | * Note how expand_stack() refuses to expand the stack all the way to | |
2237 | * abut the next virtual mapping, *unless* that mapping itself is also | |
2238 | * a stack mapping. We want to leave room for a guard page, after all | |
2239 | * (the guard page itself is not added here, that is done by the | |
2240 | * actual page faulting logic) | |
2241 | * | |
2242 | * This matches the behavior of the guard page logic (see mm/memory.c: | |
2243 | * check_stack_guard_page()), which only allows the guard page to be | |
2244 | * removed under these circumstances. | |
2245 | */ | |
b6a2fea3 OW |
2246 | #ifdef CONFIG_STACK_GROWSUP |
2247 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2248 | { | |
09884964 LT |
2249 | struct vm_area_struct *next; |
2250 | ||
2251 | address &= PAGE_MASK; | |
2252 | next = vma->vm_next; | |
2253 | if (next && next->vm_start == address + PAGE_SIZE) { | |
2254 | if (!(next->vm_flags & VM_GROWSUP)) | |
2255 | return -ENOMEM; | |
2256 | } | |
b6a2fea3 OW |
2257 | return expand_upwards(vma, address); |
2258 | } | |
2259 | ||
2260 | struct vm_area_struct * | |
2261 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
2262 | { | |
2263 | struct vm_area_struct *vma, *prev; | |
2264 | ||
2265 | addr &= PAGE_MASK; | |
2266 | vma = find_vma_prev(mm, addr, &prev); | |
2267 | if (vma && (vma->vm_start <= addr)) | |
2268 | return vma; | |
1c127185 | 2269 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 2270 | return NULL; |
cea10a19 ML |
2271 | if (prev->vm_flags & VM_LOCKED) |
2272 | __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL); | |
b6a2fea3 OW |
2273 | return prev; |
2274 | } | |
2275 | #else | |
2276 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2277 | { | |
09884964 LT |
2278 | struct vm_area_struct *prev; |
2279 | ||
2280 | address &= PAGE_MASK; | |
2281 | prev = vma->vm_prev; | |
2282 | if (prev && prev->vm_end == address) { | |
2283 | if (!(prev->vm_flags & VM_GROWSDOWN)) | |
2284 | return -ENOMEM; | |
2285 | } | |
b6a2fea3 OW |
2286 | return expand_downwards(vma, address); |
2287 | } | |
2288 | ||
1da177e4 LT |
2289 | struct vm_area_struct * |
2290 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
2291 | { | |
2292 | struct vm_area_struct * vma; | |
2293 | unsigned long start; | |
2294 | ||
2295 | addr &= PAGE_MASK; | |
2296 | vma = find_vma(mm,addr); | |
2297 | if (!vma) | |
2298 | return NULL; | |
2299 | if (vma->vm_start <= addr) | |
2300 | return vma; | |
2301 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
2302 | return NULL; | |
2303 | start = vma->vm_start; | |
2304 | if (expand_stack(vma, addr)) | |
2305 | return NULL; | |
cea10a19 ML |
2306 | if (vma->vm_flags & VM_LOCKED) |
2307 | __mlock_vma_pages_range(vma, addr, start, NULL); | |
1da177e4 LT |
2308 | return vma; |
2309 | } | |
2310 | #endif | |
2311 | ||
1da177e4 | 2312 | /* |
2c0b3814 | 2313 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 2314 | * so release them, and do the vma updates. |
2c0b3814 HD |
2315 | * |
2316 | * Called with the mm semaphore held. | |
1da177e4 | 2317 | */ |
2c0b3814 | 2318 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2319 | { |
4f74d2c8 LT |
2320 | unsigned long nr_accounted = 0; |
2321 | ||
365e9c87 HD |
2322 | /* Update high watermark before we lower total_vm */ |
2323 | update_hiwater_vm(mm); | |
1da177e4 | 2324 | do { |
2c0b3814 HD |
2325 | long nrpages = vma_pages(vma); |
2326 | ||
4f74d2c8 LT |
2327 | if (vma->vm_flags & VM_ACCOUNT) |
2328 | nr_accounted += nrpages; | |
2c0b3814 | 2329 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 2330 | vma = remove_vma(vma); |
146425a3 | 2331 | } while (vma); |
4f74d2c8 | 2332 | vm_unacct_memory(nr_accounted); |
1da177e4 LT |
2333 | validate_mm(mm); |
2334 | } | |
2335 | ||
2336 | /* | |
2337 | * Get rid of page table information in the indicated region. | |
2338 | * | |
f10df686 | 2339 | * Called with the mm semaphore held. |
1da177e4 LT |
2340 | */ |
2341 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
2342 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
2343 | unsigned long start, unsigned long end) | |
1da177e4 | 2344 | { |
e0da382c | 2345 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
d16dfc55 | 2346 | struct mmu_gather tlb; |
1da177e4 LT |
2347 | |
2348 | lru_add_drain(); | |
2b047252 | 2349 | tlb_gather_mmu(&tlb, mm, start, end); |
365e9c87 | 2350 | update_hiwater_rss(mm); |
4f74d2c8 | 2351 | unmap_vmas(&tlb, vma, start, end); |
d16dfc55 | 2352 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
6ee8630e | 2353 | next ? next->vm_start : USER_PGTABLES_CEILING); |
d16dfc55 | 2354 | tlb_finish_mmu(&tlb, start, end); |
1da177e4 LT |
2355 | } |
2356 | ||
2357 | /* | |
2358 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
2359 | * vma list as we go.. | |
2360 | */ | |
2361 | static void | |
2362 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
2363 | struct vm_area_struct *prev, unsigned long end) | |
2364 | { | |
2365 | struct vm_area_struct **insertion_point; | |
2366 | struct vm_area_struct *tail_vma = NULL; | |
2367 | ||
2368 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 2369 | vma->vm_prev = NULL; |
1da177e4 | 2370 | do { |
d3737187 | 2371 | vma_rb_erase(vma, &mm->mm_rb); |
1da177e4 LT |
2372 | mm->map_count--; |
2373 | tail_vma = vma; | |
2374 | vma = vma->vm_next; | |
2375 | } while (vma && vma->vm_start < end); | |
2376 | *insertion_point = vma; | |
d3737187 | 2377 | if (vma) { |
297c5eee | 2378 | vma->vm_prev = prev; |
d3737187 ML |
2379 | vma_gap_update(vma); |
2380 | } else | |
2381 | mm->highest_vm_end = prev ? prev->vm_end : 0; | |
1da177e4 LT |
2382 | tail_vma->vm_next = NULL; |
2383 | mm->mmap_cache = NULL; /* Kill the cache. */ | |
2384 | } | |
2385 | ||
2386 | /* | |
659ace58 KM |
2387 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
2388 | * munmap path where it doesn't make sense to fail. | |
1da177e4 | 2389 | */ |
659ace58 | 2390 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1da177e4 LT |
2391 | unsigned long addr, int new_below) |
2392 | { | |
1da177e4 | 2393 | struct vm_area_struct *new; |
5beb4930 | 2394 | int err = -ENOMEM; |
1da177e4 | 2395 | |
a5516438 AK |
2396 | if (is_vm_hugetlb_page(vma) && (addr & |
2397 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
2398 | return -EINVAL; |
2399 | ||
e94b1766 | 2400 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 2401 | if (!new) |
5beb4930 | 2402 | goto out_err; |
1da177e4 LT |
2403 | |
2404 | /* most fields are the same, copy all, and then fixup */ | |
2405 | *new = *vma; | |
2406 | ||
5beb4930 RR |
2407 | INIT_LIST_HEAD(&new->anon_vma_chain); |
2408 | ||
1da177e4 LT |
2409 | if (new_below) |
2410 | new->vm_end = addr; | |
2411 | else { | |
2412 | new->vm_start = addr; | |
2413 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
2414 | } | |
2415 | ||
ef0855d3 ON |
2416 | err = vma_dup_policy(vma, new); |
2417 | if (err) | |
5beb4930 | 2418 | goto out_free_vma; |
1da177e4 | 2419 | |
5beb4930 RR |
2420 | if (anon_vma_clone(new, vma)) |
2421 | goto out_free_mpol; | |
2422 | ||
e9714acf | 2423 | if (new->vm_file) |
1da177e4 LT |
2424 | get_file(new->vm_file); |
2425 | ||
2426 | if (new->vm_ops && new->vm_ops->open) | |
2427 | new->vm_ops->open(new); | |
2428 | ||
2429 | if (new_below) | |
5beb4930 | 2430 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
2431 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
2432 | else | |
5beb4930 | 2433 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 2434 | |
5beb4930 RR |
2435 | /* Success. */ |
2436 | if (!err) | |
2437 | return 0; | |
2438 | ||
2439 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
2440 | if (new->vm_ops && new->vm_ops->close) |
2441 | new->vm_ops->close(new); | |
e9714acf | 2442 | if (new->vm_file) |
5beb4930 | 2443 | fput(new->vm_file); |
2aeadc30 | 2444 | unlink_anon_vmas(new); |
5beb4930 | 2445 | out_free_mpol: |
ef0855d3 | 2446 | mpol_put(vma_policy(new)); |
5beb4930 RR |
2447 | out_free_vma: |
2448 | kmem_cache_free(vm_area_cachep, new); | |
2449 | out_err: | |
2450 | return err; | |
1da177e4 LT |
2451 | } |
2452 | ||
659ace58 KM |
2453 | /* |
2454 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2455 | * either for the first part or the tail. | |
2456 | */ | |
2457 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2458 | unsigned long addr, int new_below) | |
2459 | { | |
2460 | if (mm->map_count >= sysctl_max_map_count) | |
2461 | return -ENOMEM; | |
2462 | ||
2463 | return __split_vma(mm, vma, addr, new_below); | |
2464 | } | |
2465 | ||
1da177e4 LT |
2466 | /* Munmap is split into 2 main parts -- this part which finds |
2467 | * what needs doing, and the areas themselves, which do the | |
2468 | * work. This now handles partial unmappings. | |
2469 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
2470 | */ | |
2471 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
2472 | { | |
2473 | unsigned long end; | |
146425a3 | 2474 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
2475 | |
2476 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
2477 | return -EINVAL; | |
2478 | ||
2479 | if ((len = PAGE_ALIGN(len)) == 0) | |
2480 | return -EINVAL; | |
2481 | ||
2482 | /* Find the first overlapping VMA */ | |
9be34c9d | 2483 | vma = find_vma(mm, start); |
146425a3 | 2484 | if (!vma) |
1da177e4 | 2485 | return 0; |
9be34c9d | 2486 | prev = vma->vm_prev; |
146425a3 | 2487 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2488 | |
2489 | /* if it doesn't overlap, we have nothing.. */ | |
2490 | end = start + len; | |
146425a3 | 2491 | if (vma->vm_start >= end) |
1da177e4 LT |
2492 | return 0; |
2493 | ||
2494 | /* | |
2495 | * If we need to split any vma, do it now to save pain later. | |
2496 | * | |
2497 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2498 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2499 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2500 | */ | |
146425a3 | 2501 | if (start > vma->vm_start) { |
659ace58 KM |
2502 | int error; |
2503 | ||
2504 | /* | |
2505 | * Make sure that map_count on return from munmap() will | |
2506 | * not exceed its limit; but let map_count go just above | |
2507 | * its limit temporarily, to help free resources as expected. | |
2508 | */ | |
2509 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2510 | return -ENOMEM; | |
2511 | ||
2512 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2513 | if (error) |
2514 | return error; | |
146425a3 | 2515 | prev = vma; |
1da177e4 LT |
2516 | } |
2517 | ||
2518 | /* Does it split the last one? */ | |
2519 | last = find_vma(mm, end); | |
2520 | if (last && end > last->vm_start) { | |
659ace58 | 2521 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2522 | if (error) |
2523 | return error; | |
2524 | } | |
146425a3 | 2525 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 2526 | |
ba470de4 RR |
2527 | /* |
2528 | * unlock any mlock()ed ranges before detaching vmas | |
2529 | */ | |
2530 | if (mm->locked_vm) { | |
2531 | struct vm_area_struct *tmp = vma; | |
2532 | while (tmp && tmp->vm_start < end) { | |
2533 | if (tmp->vm_flags & VM_LOCKED) { | |
2534 | mm->locked_vm -= vma_pages(tmp); | |
2535 | munlock_vma_pages_all(tmp); | |
2536 | } | |
2537 | tmp = tmp->vm_next; | |
2538 | } | |
2539 | } | |
2540 | ||
1da177e4 LT |
2541 | /* |
2542 | * Remove the vma's, and unmap the actual pages | |
2543 | */ | |
146425a3 HD |
2544 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2545 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
2546 | |
2547 | /* Fix up all other VM information */ | |
2c0b3814 | 2548 | remove_vma_list(mm, vma); |
1da177e4 LT |
2549 | |
2550 | return 0; | |
2551 | } | |
1da177e4 | 2552 | |
bfce281c | 2553 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2554 | { |
2555 | int ret; | |
bfce281c | 2556 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
2557 | |
2558 | down_write(&mm->mmap_sem); | |
a46ef99d | 2559 | ret = do_munmap(mm, start, len); |
1da177e4 LT |
2560 | up_write(&mm->mmap_sem); |
2561 | return ret; | |
2562 | } | |
a46ef99d LT |
2563 | EXPORT_SYMBOL(vm_munmap); |
2564 | ||
2565 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2566 | { | |
2567 | profile_munmap(addr); | |
bfce281c | 2568 | return vm_munmap(addr, len); |
a46ef99d | 2569 | } |
1da177e4 LT |
2570 | |
2571 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
2572 | { | |
a241ec65 | 2573 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2574 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2575 | WARN_ON(1); | |
2576 | up_read(&mm->mmap_sem); | |
2577 | } | |
2578 | #endif | |
2579 | } | |
2580 | ||
2581 | /* | |
2582 | * this is really a simplified "do_mmap". it only handles | |
2583 | * anonymous maps. eventually we may be able to do some | |
2584 | * brk-specific accounting here. | |
2585 | */ | |
e4eb1ff6 | 2586 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
1da177e4 LT |
2587 | { |
2588 | struct mm_struct * mm = current->mm; | |
2589 | struct vm_area_struct * vma, * prev; | |
2590 | unsigned long flags; | |
2591 | struct rb_node ** rb_link, * rb_parent; | |
2592 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 2593 | int error; |
1da177e4 LT |
2594 | |
2595 | len = PAGE_ALIGN(len); | |
2596 | if (!len) | |
2597 | return addr; | |
2598 | ||
3a459756 KK |
2599 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2600 | ||
2c6a1016 AV |
2601 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
2602 | if (error & ~PAGE_MASK) | |
3a459756 KK |
2603 | return error; |
2604 | ||
363ee17f DB |
2605 | error = mlock_future_check(mm, mm->def_flags, len); |
2606 | if (error) | |
2607 | return error; | |
1da177e4 LT |
2608 | |
2609 | /* | |
2610 | * mm->mmap_sem is required to protect against another thread | |
2611 | * changing the mappings in case we sleep. | |
2612 | */ | |
2613 | verify_mm_writelocked(mm); | |
2614 | ||
2615 | /* | |
2616 | * Clear old maps. this also does some error checking for us | |
2617 | */ | |
2618 | munmap_back: | |
6597d783 | 2619 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
2620 | if (do_munmap(mm, addr, len)) |
2621 | return -ENOMEM; | |
2622 | goto munmap_back; | |
2623 | } | |
2624 | ||
2625 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2626 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2627 | return -ENOMEM; |
2628 | ||
2629 | if (mm->map_count > sysctl_max_map_count) | |
2630 | return -ENOMEM; | |
2631 | ||
191c5424 | 2632 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2633 | return -ENOMEM; |
2634 | ||
1da177e4 | 2635 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2636 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2637 | NULL, NULL, pgoff, NULL); | |
2638 | if (vma) | |
1da177e4 LT |
2639 | goto out; |
2640 | ||
2641 | /* | |
2642 | * create a vma struct for an anonymous mapping | |
2643 | */ | |
c5e3b83e | 2644 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2645 | if (!vma) { |
2646 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2647 | return -ENOMEM; | |
2648 | } | |
1da177e4 | 2649 | |
5beb4930 | 2650 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2651 | vma->vm_mm = mm; |
2652 | vma->vm_start = addr; | |
2653 | vma->vm_end = addr + len; | |
2654 | vma->vm_pgoff = pgoff; | |
2655 | vma->vm_flags = flags; | |
3ed75eb8 | 2656 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2657 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2658 | out: | |
3af9e859 | 2659 | perf_event_mmap(vma); |
1da177e4 | 2660 | mm->total_vm += len >> PAGE_SHIFT; |
128557ff ML |
2661 | if (flags & VM_LOCKED) |
2662 | mm->locked_vm += (len >> PAGE_SHIFT); | |
d9104d1c | 2663 | vma->vm_flags |= VM_SOFTDIRTY; |
1da177e4 LT |
2664 | return addr; |
2665 | } | |
2666 | ||
e4eb1ff6 LT |
2667 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
2668 | { | |
2669 | struct mm_struct *mm = current->mm; | |
2670 | unsigned long ret; | |
128557ff | 2671 | bool populate; |
e4eb1ff6 LT |
2672 | |
2673 | down_write(&mm->mmap_sem); | |
2674 | ret = do_brk(addr, len); | |
128557ff | 2675 | populate = ((mm->def_flags & VM_LOCKED) != 0); |
e4eb1ff6 | 2676 | up_write(&mm->mmap_sem); |
128557ff ML |
2677 | if (populate) |
2678 | mm_populate(addr, len); | |
e4eb1ff6 LT |
2679 | return ret; |
2680 | } | |
2681 | EXPORT_SYMBOL(vm_brk); | |
1da177e4 LT |
2682 | |
2683 | /* Release all mmaps. */ | |
2684 | void exit_mmap(struct mm_struct *mm) | |
2685 | { | |
d16dfc55 | 2686 | struct mmu_gather tlb; |
ba470de4 | 2687 | struct vm_area_struct *vma; |
1da177e4 LT |
2688 | unsigned long nr_accounted = 0; |
2689 | ||
d6dd61c8 | 2690 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2691 | mmu_notifier_release(mm); |
d6dd61c8 | 2692 | |
ba470de4 RR |
2693 | if (mm->locked_vm) { |
2694 | vma = mm->mmap; | |
2695 | while (vma) { | |
2696 | if (vma->vm_flags & VM_LOCKED) | |
2697 | munlock_vma_pages_all(vma); | |
2698 | vma = vma->vm_next; | |
2699 | } | |
2700 | } | |
9480c53e JF |
2701 | |
2702 | arch_exit_mmap(mm); | |
2703 | ||
ba470de4 | 2704 | vma = mm->mmap; |
9480c53e JF |
2705 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2706 | return; | |
2707 | ||
1da177e4 | 2708 | lru_add_drain(); |
1da177e4 | 2709 | flush_cache_mm(mm); |
2b047252 | 2710 | tlb_gather_mmu(&tlb, mm, 0, -1); |
901608d9 | 2711 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2712 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
4f74d2c8 | 2713 | unmap_vmas(&tlb, vma, 0, -1); |
9ba69294 | 2714 | |
6ee8630e | 2715 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); |
853f5e26 | 2716 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 2717 | |
1da177e4 | 2718 | /* |
8f4f8c16 HD |
2719 | * Walk the list again, actually closing and freeing it, |
2720 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2721 | */ |
4f74d2c8 LT |
2722 | while (vma) { |
2723 | if (vma->vm_flags & VM_ACCOUNT) | |
2724 | nr_accounted += vma_pages(vma); | |
a8fb5618 | 2725 | vma = remove_vma(vma); |
4f74d2c8 LT |
2726 | } |
2727 | vm_unacct_memory(nr_accounted); | |
e0da382c | 2728 | |
e1f56c89 KS |
2729 | WARN_ON(atomic_long_read(&mm->nr_ptes) > |
2730 | (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); | |
1da177e4 LT |
2731 | } |
2732 | ||
2733 | /* Insert vm structure into process list sorted by address | |
2734 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
3d48ae45 | 2735 | * then i_mmap_mutex is taken here. |
1da177e4 | 2736 | */ |
6597d783 | 2737 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2738 | { |
6597d783 HD |
2739 | struct vm_area_struct *prev; |
2740 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
2741 | |
2742 | /* | |
2743 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2744 | * until its first write fault, when page's anon_vma and index | |
2745 | * are set. But now set the vm_pgoff it will almost certainly | |
2746 | * end up with (unless mremap moves it elsewhere before that | |
2747 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2748 | * | |
2749 | * By setting it to reflect the virtual start address of the | |
2750 | * vma, merges and splits can happen in a seamless way, just | |
2751 | * using the existing file pgoff checks and manipulations. | |
2752 | * Similarly in do_mmap_pgoff and in do_brk. | |
2753 | */ | |
2754 | if (!vma->vm_file) { | |
2755 | BUG_ON(vma->anon_vma); | |
2756 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2757 | } | |
6597d783 HD |
2758 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
2759 | &prev, &rb_link, &rb_parent)) | |
1da177e4 | 2760 | return -ENOMEM; |
2fd4ef85 | 2761 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2762 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2763 | return -ENOMEM; |
2b144498 | 2764 | |
1da177e4 LT |
2765 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2766 | return 0; | |
2767 | } | |
2768 | ||
2769 | /* | |
2770 | * Copy the vma structure to a new location in the same mm, | |
2771 | * prior to moving page table entries, to effect an mremap move. | |
2772 | */ | |
2773 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
38a76013 ML |
2774 | unsigned long addr, unsigned long len, pgoff_t pgoff, |
2775 | bool *need_rmap_locks) | |
1da177e4 LT |
2776 | { |
2777 | struct vm_area_struct *vma = *vmap; | |
2778 | unsigned long vma_start = vma->vm_start; | |
2779 | struct mm_struct *mm = vma->vm_mm; | |
2780 | struct vm_area_struct *new_vma, *prev; | |
2781 | struct rb_node **rb_link, *rb_parent; | |
948f017b | 2782 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
2783 | |
2784 | /* | |
2785 | * If anonymous vma has not yet been faulted, update new pgoff | |
2786 | * to match new location, to increase its chance of merging. | |
2787 | */ | |
948f017b | 2788 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
1da177e4 | 2789 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
2790 | faulted_in_anon_vma = false; |
2791 | } | |
1da177e4 | 2792 | |
6597d783 HD |
2793 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
2794 | return NULL; /* should never get here */ | |
1da177e4 LT |
2795 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
2796 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2797 | if (new_vma) { | |
2798 | /* | |
2799 | * Source vma may have been merged into new_vma | |
2800 | */ | |
948f017b AA |
2801 | if (unlikely(vma_start >= new_vma->vm_start && |
2802 | vma_start < new_vma->vm_end)) { | |
2803 | /* | |
2804 | * The only way we can get a vma_merge with | |
2805 | * self during an mremap is if the vma hasn't | |
2806 | * been faulted in yet and we were allowed to | |
2807 | * reset the dst vma->vm_pgoff to the | |
2808 | * destination address of the mremap to allow | |
2809 | * the merge to happen. mremap must change the | |
2810 | * vm_pgoff linearity between src and dst vmas | |
2811 | * (in turn preventing a vma_merge) to be | |
2812 | * safe. It is only safe to keep the vm_pgoff | |
2813 | * linear if there are no pages mapped yet. | |
2814 | */ | |
2815 | VM_BUG_ON(faulted_in_anon_vma); | |
38a76013 | 2816 | *vmap = vma = new_vma; |
108d6642 | 2817 | } |
38a76013 | 2818 | *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); |
1da177e4 | 2819 | } else { |
e94b1766 | 2820 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2821 | if (new_vma) { |
2822 | *new_vma = *vma; | |
523d4e20 ML |
2823 | new_vma->vm_start = addr; |
2824 | new_vma->vm_end = addr + len; | |
2825 | new_vma->vm_pgoff = pgoff; | |
ef0855d3 | 2826 | if (vma_dup_policy(vma, new_vma)) |
5beb4930 RR |
2827 | goto out_free_vma; |
2828 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); | |
2829 | if (anon_vma_clone(new_vma, vma)) | |
2830 | goto out_free_mempol; | |
e9714acf | 2831 | if (new_vma->vm_file) |
1da177e4 LT |
2832 | get_file(new_vma->vm_file); |
2833 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
2834 | new_vma->vm_ops->open(new_vma); | |
2835 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
38a76013 | 2836 | *need_rmap_locks = false; |
1da177e4 LT |
2837 | } |
2838 | } | |
2839 | return new_vma; | |
5beb4930 RR |
2840 | |
2841 | out_free_mempol: | |
ef0855d3 | 2842 | mpol_put(vma_policy(new_vma)); |
5beb4930 RR |
2843 | out_free_vma: |
2844 | kmem_cache_free(vm_area_cachep, new_vma); | |
2845 | return NULL; | |
1da177e4 | 2846 | } |
119f657c | 2847 | |
2848 | /* | |
2849 | * Return true if the calling process may expand its vm space by the passed | |
2850 | * number of pages | |
2851 | */ | |
2852 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2853 | { | |
2854 | unsigned long cur = mm->total_vm; /* pages */ | |
2855 | unsigned long lim; | |
2856 | ||
59e99e5b | 2857 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
119f657c | 2858 | |
2859 | if (cur + npages > lim) | |
2860 | return 0; | |
2861 | return 1; | |
2862 | } | |
fa5dc22f RM |
2863 | |
2864 | ||
b1d0e4f5 NP |
2865 | static int special_mapping_fault(struct vm_area_struct *vma, |
2866 | struct vm_fault *vmf) | |
fa5dc22f | 2867 | { |
b1d0e4f5 | 2868 | pgoff_t pgoff; |
fa5dc22f RM |
2869 | struct page **pages; |
2870 | ||
b1d0e4f5 NP |
2871 | /* |
2872 | * special mappings have no vm_file, and in that case, the mm | |
2873 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2874 | * We are allowed to do this because we are the mm; do not copy | |
2875 | * this code into drivers! | |
2876 | */ | |
2877 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2878 | |
b1d0e4f5 NP |
2879 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2880 | pgoff--; | |
fa5dc22f RM |
2881 | |
2882 | if (*pages) { | |
2883 | struct page *page = *pages; | |
2884 | get_page(page); | |
b1d0e4f5 NP |
2885 | vmf->page = page; |
2886 | return 0; | |
fa5dc22f RM |
2887 | } |
2888 | ||
b1d0e4f5 | 2889 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2890 | } |
2891 | ||
2892 | /* | |
2893 | * Having a close hook prevents vma merging regardless of flags. | |
2894 | */ | |
2895 | static void special_mapping_close(struct vm_area_struct *vma) | |
2896 | { | |
2897 | } | |
2898 | ||
f0f37e2f | 2899 | static const struct vm_operations_struct special_mapping_vmops = { |
fa5dc22f | 2900 | .close = special_mapping_close, |
b1d0e4f5 | 2901 | .fault = special_mapping_fault, |
fa5dc22f RM |
2902 | }; |
2903 | ||
2904 | /* | |
2905 | * Called with mm->mmap_sem held for writing. | |
2906 | * Insert a new vma covering the given region, with the given flags. | |
2907 | * Its pages are supplied by the given array of struct page *. | |
2908 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2909 | * The region past the last page supplied will always produce SIGBUS. | |
2910 | * The array pointer and the pages it points to are assumed to stay alive | |
2911 | * for as long as this mapping might exist. | |
2912 | */ | |
2913 | int install_special_mapping(struct mm_struct *mm, | |
2914 | unsigned long addr, unsigned long len, | |
2915 | unsigned long vm_flags, struct page **pages) | |
2916 | { | |
462e635e | 2917 | int ret; |
fa5dc22f RM |
2918 | struct vm_area_struct *vma; |
2919 | ||
2920 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2921 | if (unlikely(vma == NULL)) | |
2922 | return -ENOMEM; | |
2923 | ||
5beb4930 | 2924 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
2925 | vma->vm_mm = mm; |
2926 | vma->vm_start = addr; | |
2927 | vma->vm_end = addr + len; | |
2928 | ||
d9104d1c | 2929 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; |
3ed75eb8 | 2930 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2931 | |
2932 | vma->vm_ops = &special_mapping_vmops; | |
2933 | vma->vm_private_data = pages; | |
2934 | ||
462e635e TO |
2935 | ret = insert_vm_struct(mm, vma); |
2936 | if (ret) | |
2937 | goto out; | |
fa5dc22f RM |
2938 | |
2939 | mm->total_vm += len >> PAGE_SHIFT; | |
2940 | ||
cdd6c482 | 2941 | perf_event_mmap(vma); |
089dd79d | 2942 | |
fa5dc22f | 2943 | return 0; |
462e635e TO |
2944 | |
2945 | out: | |
2946 | kmem_cache_free(vm_area_cachep, vma); | |
2947 | return ret; | |
fa5dc22f | 2948 | } |
7906d00c AA |
2949 | |
2950 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
2951 | ||
454ed842 | 2952 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 2953 | { |
bf181b9f | 2954 | if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
2955 | /* |
2956 | * The LSB of head.next can't change from under us | |
2957 | * because we hold the mm_all_locks_mutex. | |
2958 | */ | |
572043c9 | 2959 | down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); |
7906d00c AA |
2960 | /* |
2961 | * We can safely modify head.next after taking the | |
5a505085 | 2962 | * anon_vma->root->rwsem. If some other vma in this mm shares |
7906d00c AA |
2963 | * the same anon_vma we won't take it again. |
2964 | * | |
2965 | * No need of atomic instructions here, head.next | |
2966 | * can't change from under us thanks to the | |
5a505085 | 2967 | * anon_vma->root->rwsem. |
7906d00c AA |
2968 | */ |
2969 | if (__test_and_set_bit(0, (unsigned long *) | |
bf181b9f | 2970 | &anon_vma->root->rb_root.rb_node)) |
7906d00c AA |
2971 | BUG(); |
2972 | } | |
2973 | } | |
2974 | ||
454ed842 | 2975 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
2976 | { |
2977 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2978 | /* | |
2979 | * AS_MM_ALL_LOCKS can't change from under us because | |
2980 | * we hold the mm_all_locks_mutex. | |
2981 | * | |
2982 | * Operations on ->flags have to be atomic because | |
2983 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
2984 | * mm_all_locks_mutex, there may be other cpus | |
2985 | * changing other bitflags in parallel to us. | |
2986 | */ | |
2987 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
2988 | BUG(); | |
3d48ae45 | 2989 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
7906d00c AA |
2990 | } |
2991 | } | |
2992 | ||
2993 | /* | |
2994 | * This operation locks against the VM for all pte/vma/mm related | |
2995 | * operations that could ever happen on a certain mm. This includes | |
2996 | * vmtruncate, try_to_unmap, and all page faults. | |
2997 | * | |
2998 | * The caller must take the mmap_sem in write mode before calling | |
2999 | * mm_take_all_locks(). The caller isn't allowed to release the | |
3000 | * mmap_sem until mm_drop_all_locks() returns. | |
3001 | * | |
3002 | * mmap_sem in write mode is required in order to block all operations | |
3003 | * that could modify pagetables and free pages without need of | |
3004 | * altering the vma layout (for example populate_range() with | |
3005 | * nonlinear vmas). It's also needed in write mode to avoid new | |
3006 | * anon_vmas to be associated with existing vmas. | |
3007 | * | |
3008 | * A single task can't take more than one mm_take_all_locks() in a row | |
3009 | * or it would deadlock. | |
3010 | * | |
bf181b9f | 3011 | * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in |
7906d00c AA |
3012 | * mapping->flags avoid to take the same lock twice, if more than one |
3013 | * vma in this mm is backed by the same anon_vma or address_space. | |
3014 | * | |
3015 | * We can take all the locks in random order because the VM code | |
631b0cfd | 3016 | * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never |
7906d00c AA |
3017 | * takes more than one of them in a row. Secondly we're protected |
3018 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
3019 | * | |
3020 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
3021 | * that may have to take thousand of locks. | |
3022 | * | |
3023 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
3024 | */ | |
3025 | int mm_take_all_locks(struct mm_struct *mm) | |
3026 | { | |
3027 | struct vm_area_struct *vma; | |
5beb4930 | 3028 | struct anon_vma_chain *avc; |
7906d00c AA |
3029 | |
3030 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3031 | ||
3032 | mutex_lock(&mm_all_locks_mutex); | |
3033 | ||
3034 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3035 | if (signal_pending(current)) | |
3036 | goto out_unlock; | |
7906d00c | 3037 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 3038 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 3039 | } |
7cd5a02f PZ |
3040 | |
3041 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3042 | if (signal_pending(current)) | |
3043 | goto out_unlock; | |
3044 | if (vma->anon_vma) | |
5beb4930 RR |
3045 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3046 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 3047 | } |
7cd5a02f | 3048 | |
584cff54 | 3049 | return 0; |
7906d00c AA |
3050 | |
3051 | out_unlock: | |
584cff54 KC |
3052 | mm_drop_all_locks(mm); |
3053 | return -EINTR; | |
7906d00c AA |
3054 | } |
3055 | ||
3056 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
3057 | { | |
bf181b9f | 3058 | if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
3059 | /* |
3060 | * The LSB of head.next can't change to 0 from under | |
3061 | * us because we hold the mm_all_locks_mutex. | |
3062 | * | |
3063 | * We must however clear the bitflag before unlocking | |
bf181b9f | 3064 | * the vma so the users using the anon_vma->rb_root will |
7906d00c AA |
3065 | * never see our bitflag. |
3066 | * | |
3067 | * No need of atomic instructions here, head.next | |
3068 | * can't change from under us until we release the | |
5a505085 | 3069 | * anon_vma->root->rwsem. |
7906d00c AA |
3070 | */ |
3071 | if (!__test_and_clear_bit(0, (unsigned long *) | |
bf181b9f | 3072 | &anon_vma->root->rb_root.rb_node)) |
7906d00c | 3073 | BUG(); |
08b52706 | 3074 | anon_vma_unlock_write(anon_vma); |
7906d00c AA |
3075 | } |
3076 | } | |
3077 | ||
3078 | static void vm_unlock_mapping(struct address_space *mapping) | |
3079 | { | |
3080 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
3081 | /* | |
3082 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
3083 | * because we hold the mm_all_locks_mutex. | |
3084 | */ | |
3d48ae45 | 3085 | mutex_unlock(&mapping->i_mmap_mutex); |
7906d00c AA |
3086 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
3087 | &mapping->flags)) | |
3088 | BUG(); | |
3089 | } | |
3090 | } | |
3091 | ||
3092 | /* | |
3093 | * The mmap_sem cannot be released by the caller until | |
3094 | * mm_drop_all_locks() returns. | |
3095 | */ | |
3096 | void mm_drop_all_locks(struct mm_struct *mm) | |
3097 | { | |
3098 | struct vm_area_struct *vma; | |
5beb4930 | 3099 | struct anon_vma_chain *avc; |
7906d00c AA |
3100 | |
3101 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3102 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
3103 | ||
3104 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3105 | if (vma->anon_vma) | |
5beb4930 RR |
3106 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3107 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
3108 | if (vma->vm_file && vma->vm_file->f_mapping) |
3109 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
3110 | } | |
3111 | ||
3112 | mutex_unlock(&mm_all_locks_mutex); | |
3113 | } | |
8feae131 DH |
3114 | |
3115 | /* | |
3116 | * initialise the VMA slab | |
3117 | */ | |
3118 | void __init mmap_init(void) | |
3119 | { | |
00a62ce9 KM |
3120 | int ret; |
3121 | ||
3122 | ret = percpu_counter_init(&vm_committed_as, 0); | |
3123 | VM_BUG_ON(ret); | |
8feae131 | 3124 | } |
c9b1d098 AS |
3125 | |
3126 | /* | |
3127 | * Initialise sysctl_user_reserve_kbytes. | |
3128 | * | |
3129 | * This is intended to prevent a user from starting a single memory hogging | |
3130 | * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER | |
3131 | * mode. | |
3132 | * | |
3133 | * The default value is min(3% of free memory, 128MB) | |
3134 | * 128MB is enough to recover with sshd/login, bash, and top/kill. | |
3135 | */ | |
1640879a | 3136 | static int init_user_reserve(void) |
c9b1d098 AS |
3137 | { |
3138 | unsigned long free_kbytes; | |
3139 | ||
3140 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3141 | ||
3142 | sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); | |
3143 | return 0; | |
3144 | } | |
3145 | module_init(init_user_reserve) | |
4eeab4f5 AS |
3146 | |
3147 | /* | |
3148 | * Initialise sysctl_admin_reserve_kbytes. | |
3149 | * | |
3150 | * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin | |
3151 | * to log in and kill a memory hogging process. | |
3152 | * | |
3153 | * Systems with more than 256MB will reserve 8MB, enough to recover | |
3154 | * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will | |
3155 | * only reserve 3% of free pages by default. | |
3156 | */ | |
1640879a | 3157 | static int init_admin_reserve(void) |
4eeab4f5 AS |
3158 | { |
3159 | unsigned long free_kbytes; | |
3160 | ||
3161 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3162 | ||
3163 | sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); | |
3164 | return 0; | |
3165 | } | |
3166 | module_init(init_admin_reserve) | |
1640879a AS |
3167 | |
3168 | /* | |
3169 | * Reinititalise user and admin reserves if memory is added or removed. | |
3170 | * | |
3171 | * The default user reserve max is 128MB, and the default max for the | |
3172 | * admin reserve is 8MB. These are usually, but not always, enough to | |
3173 | * enable recovery from a memory hogging process using login/sshd, a shell, | |
3174 | * and tools like top. It may make sense to increase or even disable the | |
3175 | * reserve depending on the existence of swap or variations in the recovery | |
3176 | * tools. So, the admin may have changed them. | |
3177 | * | |
3178 | * If memory is added and the reserves have been eliminated or increased above | |
3179 | * the default max, then we'll trust the admin. | |
3180 | * | |
3181 | * If memory is removed and there isn't enough free memory, then we | |
3182 | * need to reset the reserves. | |
3183 | * | |
3184 | * Otherwise keep the reserve set by the admin. | |
3185 | */ | |
3186 | static int reserve_mem_notifier(struct notifier_block *nb, | |
3187 | unsigned long action, void *data) | |
3188 | { | |
3189 | unsigned long tmp, free_kbytes; | |
3190 | ||
3191 | switch (action) { | |
3192 | case MEM_ONLINE: | |
3193 | /* Default max is 128MB. Leave alone if modified by operator. */ | |
3194 | tmp = sysctl_user_reserve_kbytes; | |
3195 | if (0 < tmp && tmp < (1UL << 17)) | |
3196 | init_user_reserve(); | |
3197 | ||
3198 | /* Default max is 8MB. Leave alone if modified by operator. */ | |
3199 | tmp = sysctl_admin_reserve_kbytes; | |
3200 | if (0 < tmp && tmp < (1UL << 13)) | |
3201 | init_admin_reserve(); | |
3202 | ||
3203 | break; | |
3204 | case MEM_OFFLINE: | |
3205 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3206 | ||
3207 | if (sysctl_user_reserve_kbytes > free_kbytes) { | |
3208 | init_user_reserve(); | |
3209 | pr_info("vm.user_reserve_kbytes reset to %lu\n", | |
3210 | sysctl_user_reserve_kbytes); | |
3211 | } | |
3212 | ||
3213 | if (sysctl_admin_reserve_kbytes > free_kbytes) { | |
3214 | init_admin_reserve(); | |
3215 | pr_info("vm.admin_reserve_kbytes reset to %lu\n", | |
3216 | sysctl_admin_reserve_kbytes); | |
3217 | } | |
3218 | break; | |
3219 | default: | |
3220 | break; | |
3221 | } | |
3222 | return NOTIFY_OK; | |
3223 | } | |
3224 | ||
3225 | static struct notifier_block reserve_mem_nb = { | |
3226 | .notifier_call = reserve_mem_notifier, | |
3227 | }; | |
3228 | ||
3229 | static int __meminit init_reserve_notifier(void) | |
3230 | { | |
3231 | if (register_hotmemory_notifier(&reserve_mem_nb)) | |
3232 | printk("Failed registering memory add/remove notifier for admin reserve"); | |
3233 | ||
3234 | return 0; | |
3235 | } | |
3236 | module_init(init_reserve_notifier) |