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Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mmap.c | |
3 | * | |
4 | * Written by obz. | |
5 | * | |
046c6884 | 6 | * Address space accounting code <[email protected]> |
1da177e4 LT |
7 | */ |
8 | ||
b1de0d13 MH |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | ||
e8420a8e | 11 | #include <linux/kernel.h> |
1da177e4 | 12 | #include <linux/slab.h> |
4af3c9cc | 13 | #include <linux/backing-dev.h> |
1da177e4 | 14 | #include <linux/mm.h> |
615d6e87 | 15 | #include <linux/vmacache.h> |
1da177e4 LT |
16 | #include <linux/shm.h> |
17 | #include <linux/mman.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/syscalls.h> | |
c59ede7b | 21 | #include <linux/capability.h> |
1da177e4 LT |
22 | #include <linux/init.h> |
23 | #include <linux/file.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/personality.h> | |
26 | #include <linux/security.h> | |
27 | #include <linux/hugetlb.h> | |
28 | #include <linux/profile.h> | |
b95f1b31 | 29 | #include <linux/export.h> |
1da177e4 LT |
30 | #include <linux/mount.h> |
31 | #include <linux/mempolicy.h> | |
32 | #include <linux/rmap.h> | |
cddb8a5c | 33 | #include <linux/mmu_notifier.h> |
cdd6c482 | 34 | #include <linux/perf_event.h> |
120a795d | 35 | #include <linux/audit.h> |
b15d00b6 | 36 | #include <linux/khugepaged.h> |
2b144498 | 37 | #include <linux/uprobes.h> |
d3737187 | 38 | #include <linux/rbtree_augmented.h> |
cf4aebc2 | 39 | #include <linux/sched/sysctl.h> |
1640879a AS |
40 | #include <linux/notifier.h> |
41 | #include <linux/memory.h> | |
b1de0d13 | 42 | #include <linux/printk.h> |
1da177e4 LT |
43 | |
44 | #include <asm/uaccess.h> | |
45 | #include <asm/cacheflush.h> | |
46 | #include <asm/tlb.h> | |
d6dd61c8 | 47 | #include <asm/mmu_context.h> |
1da177e4 | 48 | |
42b77728 JB |
49 | #include "internal.h" |
50 | ||
3a459756 KK |
51 | #ifndef arch_mmap_check |
52 | #define arch_mmap_check(addr, len, flags) (0) | |
53 | #endif | |
54 | ||
08e7d9b5 MS |
55 | #ifndef arch_rebalance_pgtables |
56 | #define arch_rebalance_pgtables(addr, len) (addr) | |
57 | #endif | |
58 | ||
e0da382c HD |
59 | static void unmap_region(struct mm_struct *mm, |
60 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
61 | unsigned long start, unsigned long end); | |
62 | ||
1da177e4 LT |
63 | /* description of effects of mapping type and prot in current implementation. |
64 | * this is due to the limited x86 page protection hardware. The expected | |
65 | * behavior is in parens: | |
66 | * | |
67 | * map_type prot | |
68 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
69 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
70 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
71 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
72 | * | |
73 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
74 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
75 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
76 | * | |
77 | */ | |
78 | pgprot_t protection_map[16] = { | |
79 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
80 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
81 | }; | |
82 | ||
804af2cf HD |
83 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
84 | { | |
b845f313 DK |
85 | return __pgprot(pgprot_val(protection_map[vm_flags & |
86 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
87 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
88 | } |
89 | EXPORT_SYMBOL(vm_get_page_prot); | |
90 | ||
34679d7e SL |
91 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
92 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ | |
49f0ce5f | 93 | unsigned long sysctl_overcommit_kbytes __read_mostly; |
c3d8c141 | 94 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
c9b1d098 | 95 | unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */ |
4eeab4f5 | 96 | unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */ |
34679d7e SL |
97 | /* |
98 | * Make sure vm_committed_as in one cacheline and not cacheline shared with | |
99 | * other variables. It can be updated by several CPUs frequently. | |
100 | */ | |
101 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; | |
1da177e4 | 102 | |
997071bc S |
103 | /* |
104 | * The global memory commitment made in the system can be a metric | |
105 | * that can be used to drive ballooning decisions when Linux is hosted | |
106 | * as a guest. On Hyper-V, the host implements a policy engine for dynamically | |
107 | * balancing memory across competing virtual machines that are hosted. | |
108 | * Several metrics drive this policy engine including the guest reported | |
109 | * memory commitment. | |
110 | */ | |
111 | unsigned long vm_memory_committed(void) | |
112 | { | |
113 | return percpu_counter_read_positive(&vm_committed_as); | |
114 | } | |
115 | EXPORT_SYMBOL_GPL(vm_memory_committed); | |
116 | ||
1da177e4 LT |
117 | /* |
118 | * Check that a process has enough memory to allocate a new virtual | |
119 | * mapping. 0 means there is enough memory for the allocation to | |
120 | * succeed and -ENOMEM implies there is not. | |
121 | * | |
122 | * We currently support three overcommit policies, which are set via the | |
123 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
124 | * | |
125 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
126 | * Additional code 2002 Jul 20 by Robert Love. | |
127 | * | |
128 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
129 | * | |
130 | * Note this is a helper function intended to be used by LSMs which | |
131 | * wish to use this logic. | |
132 | */ | |
34b4e4aa | 133 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 | 134 | { |
c9b1d098 | 135 | unsigned long free, allowed, reserve; |
1da177e4 LT |
136 | |
137 | vm_acct_memory(pages); | |
138 | ||
139 | /* | |
140 | * Sometimes we want to use more memory than we have | |
141 | */ | |
142 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
143 | return 0; | |
144 | ||
145 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
c15bef30 DF |
146 | free = global_page_state(NR_FREE_PAGES); |
147 | free += global_page_state(NR_FILE_PAGES); | |
148 | ||
149 | /* | |
150 | * shmem pages shouldn't be counted as free in this | |
151 | * case, they can't be purged, only swapped out, and | |
152 | * that won't affect the overall amount of available | |
153 | * memory in the system. | |
154 | */ | |
155 | free -= global_page_state(NR_SHMEM); | |
1da177e4 | 156 | |
ec8acf20 | 157 | free += get_nr_swap_pages(); |
1da177e4 LT |
158 | |
159 | /* | |
160 | * Any slabs which are created with the | |
161 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
162 | * which are reclaimable, under pressure. The dentry | |
163 | * cache and most inode caches should fall into this | |
164 | */ | |
972d1a7b | 165 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 | 166 | |
6d9f7839 HA |
167 | /* |
168 | * Leave reserved pages. The pages are not for anonymous pages. | |
169 | */ | |
c15bef30 | 170 | if (free <= totalreserve_pages) |
6d9f7839 HA |
171 | goto error; |
172 | else | |
c15bef30 | 173 | free -= totalreserve_pages; |
6d9f7839 HA |
174 | |
175 | /* | |
4eeab4f5 | 176 | * Reserve some for root |
6d9f7839 | 177 | */ |
1da177e4 | 178 | if (!cap_sys_admin) |
4eeab4f5 | 179 | free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); |
1da177e4 LT |
180 | |
181 | if (free > pages) | |
182 | return 0; | |
6d9f7839 HA |
183 | |
184 | goto error; | |
1da177e4 LT |
185 | } |
186 | ||
00619bcc | 187 | allowed = vm_commit_limit(); |
1da177e4 | 188 | /* |
4eeab4f5 | 189 | * Reserve some for root |
1da177e4 LT |
190 | */ |
191 | if (!cap_sys_admin) | |
4eeab4f5 | 192 | allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); |
1da177e4 | 193 | |
c9b1d098 AS |
194 | /* |
195 | * Don't let a single process grow so big a user can't recover | |
196 | */ | |
197 | if (mm) { | |
198 | reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10); | |
199 | allowed -= min(mm->total_vm / 32, reserve); | |
200 | } | |
1da177e4 | 201 | |
00a62ce9 | 202 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 203 | return 0; |
6d9f7839 | 204 | error: |
1da177e4 LT |
205 | vm_unacct_memory(pages); |
206 | ||
207 | return -ENOMEM; | |
208 | } | |
209 | ||
1da177e4 | 210 | /* |
3d48ae45 | 211 | * Requires inode->i_mapping->i_mmap_mutex |
1da177e4 LT |
212 | */ |
213 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
214 | struct file *file, struct address_space *mapping) | |
215 | { | |
216 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 217 | atomic_inc(&file_inode(file)->i_writecount); |
1da177e4 LT |
218 | if (vma->vm_flags & VM_SHARED) |
219 | mapping->i_mmap_writable--; | |
220 | ||
221 | flush_dcache_mmap_lock(mapping); | |
222 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
6b2dbba8 | 223 | list_del_init(&vma->shared.nonlinear); |
1da177e4 | 224 | else |
6b2dbba8 | 225 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4 LT |
226 | flush_dcache_mmap_unlock(mapping); |
227 | } | |
228 | ||
229 | /* | |
6b2dbba8 | 230 | * Unlink a file-based vm structure from its interval tree, to hide |
a8fb5618 | 231 | * vma from rmap and vmtruncate before freeing its page tables. |
1da177e4 | 232 | */ |
a8fb5618 | 233 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
234 | { |
235 | struct file *file = vma->vm_file; | |
236 | ||
1da177e4 LT |
237 | if (file) { |
238 | struct address_space *mapping = file->f_mapping; | |
3d48ae45 | 239 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 240 | __remove_shared_vm_struct(vma, file, mapping); |
3d48ae45 | 241 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 242 | } |
a8fb5618 HD |
243 | } |
244 | ||
245 | /* | |
246 | * Close a vm structure and free it, returning the next. | |
247 | */ | |
248 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
249 | { | |
250 | struct vm_area_struct *next = vma->vm_next; | |
251 | ||
a8fb5618 | 252 | might_sleep(); |
1da177e4 LT |
253 | if (vma->vm_ops && vma->vm_ops->close) |
254 | vma->vm_ops->close(vma); | |
e9714acf | 255 | if (vma->vm_file) |
a8fb5618 | 256 | fput(vma->vm_file); |
f0be3d32 | 257 | mpol_put(vma_policy(vma)); |
1da177e4 | 258 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 259 | return next; |
1da177e4 LT |
260 | } |
261 | ||
e4eb1ff6 LT |
262 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
263 | ||
6a6160a7 | 264 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
265 | { |
266 | unsigned long rlim, retval; | |
267 | unsigned long newbrk, oldbrk; | |
268 | struct mm_struct *mm = current->mm; | |
a5b4592c | 269 | unsigned long min_brk; |
128557ff | 270 | bool populate; |
1da177e4 LT |
271 | |
272 | down_write(&mm->mmap_sem); | |
273 | ||
a5b4592c | 274 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
275 | /* |
276 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
277 | * randomize_va_space to 2, which will still cause mm->start_brk | |
278 | * to be arbitrarily shifted | |
279 | */ | |
4471a675 | 280 | if (current->brk_randomized) |
5520e894 JK |
281 | min_brk = mm->start_brk; |
282 | else | |
283 | min_brk = mm->end_data; | |
a5b4592c JK |
284 | #else |
285 | min_brk = mm->start_brk; | |
286 | #endif | |
287 | if (brk < min_brk) | |
1da177e4 | 288 | goto out; |
1e624196 RG |
289 | |
290 | /* | |
291 | * Check against rlimit here. If this check is done later after the test | |
292 | * of oldbrk with newbrk then it can escape the test and let the data | |
293 | * segment grow beyond its set limit the in case where the limit is | |
294 | * not page aligned -Ram Gupta | |
295 | */ | |
59e99e5b | 296 | rlim = rlimit(RLIMIT_DATA); |
c1d171a0 JK |
297 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
298 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
299 | goto out; |
300 | ||
1da177e4 LT |
301 | newbrk = PAGE_ALIGN(brk); |
302 | oldbrk = PAGE_ALIGN(mm->brk); | |
303 | if (oldbrk == newbrk) | |
304 | goto set_brk; | |
305 | ||
306 | /* Always allow shrinking brk. */ | |
307 | if (brk <= mm->brk) { | |
308 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
309 | goto set_brk; | |
310 | goto out; | |
311 | } | |
312 | ||
1da177e4 LT |
313 | /* Check against existing mmap mappings. */ |
314 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
315 | goto out; | |
316 | ||
317 | /* Ok, looks good - let it rip. */ | |
318 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
319 | goto out; | |
128557ff | 320 | |
1da177e4 LT |
321 | set_brk: |
322 | mm->brk = brk; | |
128557ff ML |
323 | populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; |
324 | up_write(&mm->mmap_sem); | |
325 | if (populate) | |
326 | mm_populate(oldbrk, newbrk - oldbrk); | |
327 | return brk; | |
328 | ||
1da177e4 LT |
329 | out: |
330 | retval = mm->brk; | |
331 | up_write(&mm->mmap_sem); | |
332 | return retval; | |
333 | } | |
334 | ||
d3737187 ML |
335 | static long vma_compute_subtree_gap(struct vm_area_struct *vma) |
336 | { | |
337 | unsigned long max, subtree_gap; | |
338 | max = vma->vm_start; | |
339 | if (vma->vm_prev) | |
340 | max -= vma->vm_prev->vm_end; | |
341 | if (vma->vm_rb.rb_left) { | |
342 | subtree_gap = rb_entry(vma->vm_rb.rb_left, | |
343 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
344 | if (subtree_gap > max) | |
345 | max = subtree_gap; | |
346 | } | |
347 | if (vma->vm_rb.rb_right) { | |
348 | subtree_gap = rb_entry(vma->vm_rb.rb_right, | |
349 | struct vm_area_struct, vm_rb)->rb_subtree_gap; | |
350 | if (subtree_gap > max) | |
351 | max = subtree_gap; | |
352 | } | |
353 | return max; | |
354 | } | |
355 | ||
ed8ea815 | 356 | #ifdef CONFIG_DEBUG_VM_RB |
1da177e4 LT |
357 | static int browse_rb(struct rb_root *root) |
358 | { | |
5a0768f6 | 359 | int i = 0, j, bug = 0; |
1da177e4 LT |
360 | struct rb_node *nd, *pn = NULL; |
361 | unsigned long prev = 0, pend = 0; | |
362 | ||
363 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
364 | struct vm_area_struct *vma; | |
365 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
5a0768f6 | 366 | if (vma->vm_start < prev) { |
b1de0d13 | 367 | pr_info("vm_start %lx prev %lx\n", vma->vm_start, prev); |
5a0768f6 ML |
368 | bug = 1; |
369 | } | |
370 | if (vma->vm_start < pend) { | |
b1de0d13 | 371 | pr_info("vm_start %lx pend %lx\n", vma->vm_start, pend); |
5a0768f6 ML |
372 | bug = 1; |
373 | } | |
374 | if (vma->vm_start > vma->vm_end) { | |
b1de0d13 | 375 | pr_info("vm_end %lx < vm_start %lx\n", |
5a0768f6 ML |
376 | vma->vm_end, vma->vm_start); |
377 | bug = 1; | |
378 | } | |
379 | if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { | |
b1de0d13 | 380 | pr_info("free gap %lx, correct %lx\n", |
5a0768f6 ML |
381 | vma->rb_subtree_gap, |
382 | vma_compute_subtree_gap(vma)); | |
383 | bug = 1; | |
384 | } | |
1da177e4 LT |
385 | i++; |
386 | pn = nd; | |
d1af65d1 DM |
387 | prev = vma->vm_start; |
388 | pend = vma->vm_end; | |
1da177e4 LT |
389 | } |
390 | j = 0; | |
5a0768f6 | 391 | for (nd = pn; nd; nd = rb_prev(nd)) |
1da177e4 | 392 | j++; |
5a0768f6 | 393 | if (i != j) { |
b1de0d13 | 394 | pr_info("backwards %d, forwards %d\n", j, i); |
5a0768f6 | 395 | bug = 1; |
1da177e4 | 396 | } |
5a0768f6 | 397 | return bug ? -1 : i; |
1da177e4 LT |
398 | } |
399 | ||
d3737187 ML |
400 | static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) |
401 | { | |
402 | struct rb_node *nd; | |
403 | ||
404 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
405 | struct vm_area_struct *vma; | |
406 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
407 | BUG_ON(vma != ignore && | |
408 | vma->rb_subtree_gap != vma_compute_subtree_gap(vma)); | |
1da177e4 | 409 | } |
1da177e4 LT |
410 | } |
411 | ||
eafd4dc4 | 412 | static void validate_mm(struct mm_struct *mm) |
1da177e4 LT |
413 | { |
414 | int bug = 0; | |
415 | int i = 0; | |
5a0768f6 | 416 | unsigned long highest_address = 0; |
ed8ea815 ML |
417 | struct vm_area_struct *vma = mm->mmap; |
418 | while (vma) { | |
419 | struct anon_vma_chain *avc; | |
63c3b902 | 420 | vma_lock_anon_vma(vma); |
ed8ea815 ML |
421 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
422 | anon_vma_interval_tree_verify(avc); | |
63c3b902 | 423 | vma_unlock_anon_vma(vma); |
5a0768f6 | 424 | highest_address = vma->vm_end; |
ed8ea815 | 425 | vma = vma->vm_next; |
1da177e4 LT |
426 | i++; |
427 | } | |
5a0768f6 | 428 | if (i != mm->map_count) { |
b1de0d13 | 429 | pr_info("map_count %d vm_next %d\n", mm->map_count, i); |
5a0768f6 ML |
430 | bug = 1; |
431 | } | |
432 | if (highest_address != mm->highest_vm_end) { | |
b1de0d13 | 433 | pr_info("mm->highest_vm_end %lx, found %lx\n", |
5a0768f6 ML |
434 | mm->highest_vm_end, highest_address); |
435 | bug = 1; | |
436 | } | |
1da177e4 | 437 | i = browse_rb(&mm->mm_rb); |
5a0768f6 | 438 | if (i != mm->map_count) { |
b1de0d13 | 439 | pr_info("map_count %d rb %d\n", mm->map_count, i); |
5a0768f6 ML |
440 | bug = 1; |
441 | } | |
46a350ef | 442 | BUG_ON(bug); |
1da177e4 LT |
443 | } |
444 | #else | |
d3737187 | 445 | #define validate_mm_rb(root, ignore) do { } while (0) |
1da177e4 LT |
446 | #define validate_mm(mm) do { } while (0) |
447 | #endif | |
448 | ||
d3737187 ML |
449 | RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, |
450 | unsigned long, rb_subtree_gap, vma_compute_subtree_gap) | |
451 | ||
452 | /* | |
453 | * Update augmented rbtree rb_subtree_gap values after vma->vm_start or | |
454 | * vma->vm_prev->vm_end values changed, without modifying the vma's position | |
455 | * in the rbtree. | |
456 | */ | |
457 | static void vma_gap_update(struct vm_area_struct *vma) | |
458 | { | |
459 | /* | |
460 | * As it turns out, RB_DECLARE_CALLBACKS() already created a callback | |
461 | * function that does exacltly what we want. | |
462 | */ | |
463 | vma_gap_callbacks_propagate(&vma->vm_rb, NULL); | |
464 | } | |
465 | ||
466 | static inline void vma_rb_insert(struct vm_area_struct *vma, | |
467 | struct rb_root *root) | |
468 | { | |
469 | /* All rb_subtree_gap values must be consistent prior to insertion */ | |
470 | validate_mm_rb(root, NULL); | |
471 | ||
472 | rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
473 | } | |
474 | ||
475 | static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) | |
476 | { | |
477 | /* | |
478 | * All rb_subtree_gap values must be consistent prior to erase, | |
479 | * with the possible exception of the vma being erased. | |
480 | */ | |
481 | validate_mm_rb(root, vma); | |
482 | ||
483 | /* | |
484 | * Note rb_erase_augmented is a fairly large inline function, | |
485 | * so make sure we instantiate it only once with our desired | |
486 | * augmented rbtree callbacks. | |
487 | */ | |
488 | rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); | |
489 | } | |
490 | ||
bf181b9f ML |
491 | /* |
492 | * vma has some anon_vma assigned, and is already inserted on that | |
493 | * anon_vma's interval trees. | |
494 | * | |
495 | * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the | |
496 | * vma must be removed from the anon_vma's interval trees using | |
497 | * anon_vma_interval_tree_pre_update_vma(). | |
498 | * | |
499 | * After the update, the vma will be reinserted using | |
500 | * anon_vma_interval_tree_post_update_vma(). | |
501 | * | |
502 | * The entire update must be protected by exclusive mmap_sem and by | |
503 | * the root anon_vma's mutex. | |
504 | */ | |
505 | static inline void | |
506 | anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) | |
507 | { | |
508 | struct anon_vma_chain *avc; | |
509 | ||
510 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
511 | anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); | |
512 | } | |
513 | ||
514 | static inline void | |
515 | anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) | |
516 | { | |
517 | struct anon_vma_chain *avc; | |
518 | ||
519 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
520 | anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); | |
521 | } | |
522 | ||
6597d783 HD |
523 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
524 | unsigned long end, struct vm_area_struct **pprev, | |
525 | struct rb_node ***rb_link, struct rb_node **rb_parent) | |
1da177e4 | 526 | { |
6597d783 | 527 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
1da177e4 LT |
528 | |
529 | __rb_link = &mm->mm_rb.rb_node; | |
530 | rb_prev = __rb_parent = NULL; | |
1da177e4 LT |
531 | |
532 | while (*__rb_link) { | |
533 | struct vm_area_struct *vma_tmp; | |
534 | ||
535 | __rb_parent = *__rb_link; | |
536 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
537 | ||
538 | if (vma_tmp->vm_end > addr) { | |
6597d783 HD |
539 | /* Fail if an existing vma overlaps the area */ |
540 | if (vma_tmp->vm_start < end) | |
541 | return -ENOMEM; | |
1da177e4 LT |
542 | __rb_link = &__rb_parent->rb_left; |
543 | } else { | |
544 | rb_prev = __rb_parent; | |
545 | __rb_link = &__rb_parent->rb_right; | |
546 | } | |
547 | } | |
548 | ||
549 | *pprev = NULL; | |
550 | if (rb_prev) | |
551 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
552 | *rb_link = __rb_link; | |
553 | *rb_parent = __rb_parent; | |
6597d783 | 554 | return 0; |
1da177e4 LT |
555 | } |
556 | ||
e8420a8e CH |
557 | static unsigned long count_vma_pages_range(struct mm_struct *mm, |
558 | unsigned long addr, unsigned long end) | |
559 | { | |
560 | unsigned long nr_pages = 0; | |
561 | struct vm_area_struct *vma; | |
562 | ||
563 | /* Find first overlaping mapping */ | |
564 | vma = find_vma_intersection(mm, addr, end); | |
565 | if (!vma) | |
566 | return 0; | |
567 | ||
568 | nr_pages = (min(end, vma->vm_end) - | |
569 | max(addr, vma->vm_start)) >> PAGE_SHIFT; | |
570 | ||
571 | /* Iterate over the rest of the overlaps */ | |
572 | for (vma = vma->vm_next; vma; vma = vma->vm_next) { | |
573 | unsigned long overlap_len; | |
574 | ||
575 | if (vma->vm_start > end) | |
576 | break; | |
577 | ||
578 | overlap_len = min(end, vma->vm_end) - vma->vm_start; | |
579 | nr_pages += overlap_len >> PAGE_SHIFT; | |
580 | } | |
581 | ||
582 | return nr_pages; | |
583 | } | |
584 | ||
1da177e4 LT |
585 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
586 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
587 | { | |
d3737187 ML |
588 | /* Update tracking information for the gap following the new vma. */ |
589 | if (vma->vm_next) | |
590 | vma_gap_update(vma->vm_next); | |
591 | else | |
592 | mm->highest_vm_end = vma->vm_end; | |
593 | ||
594 | /* | |
595 | * vma->vm_prev wasn't known when we followed the rbtree to find the | |
596 | * correct insertion point for that vma. As a result, we could not | |
597 | * update the vma vm_rb parents rb_subtree_gap values on the way down. | |
598 | * So, we first insert the vma with a zero rb_subtree_gap value | |
599 | * (to be consistent with what we did on the way down), and then | |
600 | * immediately update the gap to the correct value. Finally we | |
601 | * rebalance the rbtree after all augmented values have been set. | |
602 | */ | |
1da177e4 | 603 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
d3737187 ML |
604 | vma->rb_subtree_gap = 0; |
605 | vma_gap_update(vma); | |
606 | vma_rb_insert(vma, &mm->mm_rb); | |
1da177e4 LT |
607 | } |
608 | ||
cb8f488c | 609 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 610 | { |
48aae425 | 611 | struct file *file; |
1da177e4 LT |
612 | |
613 | file = vma->vm_file; | |
614 | if (file) { | |
615 | struct address_space *mapping = file->f_mapping; | |
616 | ||
617 | if (vma->vm_flags & VM_DENYWRITE) | |
496ad9aa | 618 | atomic_dec(&file_inode(file)->i_writecount); |
1da177e4 LT |
619 | if (vma->vm_flags & VM_SHARED) |
620 | mapping->i_mmap_writable++; | |
621 | ||
622 | flush_dcache_mmap_lock(mapping); | |
623 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
624 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
625 | else | |
6b2dbba8 | 626 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4 LT |
627 | flush_dcache_mmap_unlock(mapping); |
628 | } | |
629 | } | |
630 | ||
631 | static void | |
632 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
633 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
634 | struct rb_node *rb_parent) | |
635 | { | |
636 | __vma_link_list(mm, vma, prev, rb_parent); | |
637 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
638 | } |
639 | ||
640 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
641 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
642 | struct rb_node *rb_parent) | |
643 | { | |
644 | struct address_space *mapping = NULL; | |
645 | ||
64ac4940 | 646 | if (vma->vm_file) { |
1da177e4 | 647 | mapping = vma->vm_file->f_mapping; |
3d48ae45 | 648 | mutex_lock(&mapping->i_mmap_mutex); |
64ac4940 | 649 | } |
1da177e4 LT |
650 | |
651 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
652 | __vma_link_file(vma); | |
653 | ||
1da177e4 | 654 | if (mapping) |
3d48ae45 | 655 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
656 | |
657 | mm->map_count++; | |
658 | validate_mm(mm); | |
659 | } | |
660 | ||
661 | /* | |
88f6b4c3 | 662 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
6b2dbba8 | 663 | * mm's list and rbtree. It has already been inserted into the interval tree. |
1da177e4 | 664 | */ |
48aae425 | 665 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 666 | { |
6597d783 | 667 | struct vm_area_struct *prev; |
48aae425 | 668 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 669 | |
6597d783 HD |
670 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
671 | &prev, &rb_link, &rb_parent)) | |
672 | BUG(); | |
1da177e4 LT |
673 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
674 | mm->map_count++; | |
675 | } | |
676 | ||
677 | static inline void | |
678 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
679 | struct vm_area_struct *prev) | |
680 | { | |
d3737187 | 681 | struct vm_area_struct *next; |
297c5eee | 682 | |
d3737187 ML |
683 | vma_rb_erase(vma, &mm->mm_rb); |
684 | prev->vm_next = next = vma->vm_next; | |
297c5eee LT |
685 | if (next) |
686 | next->vm_prev = prev; | |
615d6e87 DB |
687 | |
688 | /* Kill the cache */ | |
689 | vmacache_invalidate(mm); | |
1da177e4 LT |
690 | } |
691 | ||
692 | /* | |
693 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
694 | * is already present in an i_mmap tree without adjusting the tree. | |
695 | * The following helper function should be used when such adjustments | |
696 | * are necessary. The "insert" vma (if any) is to be inserted | |
697 | * before we drop the necessary locks. | |
698 | */ | |
5beb4930 | 699 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
700 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
701 | { | |
702 | struct mm_struct *mm = vma->vm_mm; | |
703 | struct vm_area_struct *next = vma->vm_next; | |
704 | struct vm_area_struct *importer = NULL; | |
705 | struct address_space *mapping = NULL; | |
6b2dbba8 | 706 | struct rb_root *root = NULL; |
012f1800 | 707 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 708 | struct file *file = vma->vm_file; |
d3737187 | 709 | bool start_changed = false, end_changed = false; |
1da177e4 LT |
710 | long adjust_next = 0; |
711 | int remove_next = 0; | |
712 | ||
713 | if (next && !insert) { | |
287d97ac LT |
714 | struct vm_area_struct *exporter = NULL; |
715 | ||
1da177e4 LT |
716 | if (end >= next->vm_end) { |
717 | /* | |
718 | * vma expands, overlapping all the next, and | |
719 | * perhaps the one after too (mprotect case 6). | |
720 | */ | |
721 | again: remove_next = 1 + (end > next->vm_end); | |
722 | end = next->vm_end; | |
287d97ac | 723 | exporter = next; |
1da177e4 LT |
724 | importer = vma; |
725 | } else if (end > next->vm_start) { | |
726 | /* | |
727 | * vma expands, overlapping part of the next: | |
728 | * mprotect case 5 shifting the boundary up. | |
729 | */ | |
730 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 731 | exporter = next; |
1da177e4 LT |
732 | importer = vma; |
733 | } else if (end < vma->vm_end) { | |
734 | /* | |
735 | * vma shrinks, and !insert tells it's not | |
736 | * split_vma inserting another: so it must be | |
737 | * mprotect case 4 shifting the boundary down. | |
738 | */ | |
739 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
287d97ac | 740 | exporter = vma; |
1da177e4 LT |
741 | importer = next; |
742 | } | |
1da177e4 | 743 | |
5beb4930 RR |
744 | /* |
745 | * Easily overlooked: when mprotect shifts the boundary, | |
746 | * make sure the expanding vma has anon_vma set if the | |
747 | * shrinking vma had, to cover any anon pages imported. | |
748 | */ | |
287d97ac LT |
749 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
750 | if (anon_vma_clone(importer, exporter)) | |
5beb4930 | 751 | return -ENOMEM; |
287d97ac | 752 | importer->anon_vma = exporter->anon_vma; |
5beb4930 RR |
753 | } |
754 | } | |
755 | ||
1da177e4 LT |
756 | if (file) { |
757 | mapping = file->f_mapping; | |
682968e0 | 758 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
1da177e4 | 759 | root = &mapping->i_mmap; |
cbc91f71 | 760 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); |
682968e0 SD |
761 | |
762 | if (adjust_next) | |
cbc91f71 SD |
763 | uprobe_munmap(next, next->vm_start, |
764 | next->vm_end); | |
682968e0 SD |
765 | } |
766 | ||
3d48ae45 | 767 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 768 | if (insert) { |
1da177e4 | 769 | /* |
6b2dbba8 | 770 | * Put into interval tree now, so instantiated pages |
1da177e4 LT |
771 | * are visible to arm/parisc __flush_dcache_page |
772 | * throughout; but we cannot insert into address | |
773 | * space until vma start or end is updated. | |
774 | */ | |
775 | __vma_link_file(insert); | |
776 | } | |
777 | } | |
778 | ||
94fcc585 AA |
779 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
780 | ||
bf181b9f ML |
781 | anon_vma = vma->anon_vma; |
782 | if (!anon_vma && adjust_next) | |
783 | anon_vma = next->anon_vma; | |
784 | if (anon_vma) { | |
ca42b26a ML |
785 | VM_BUG_ON(adjust_next && next->anon_vma && |
786 | anon_vma != next->anon_vma); | |
4fc3f1d6 | 787 | anon_vma_lock_write(anon_vma); |
bf181b9f ML |
788 | anon_vma_interval_tree_pre_update_vma(vma); |
789 | if (adjust_next) | |
790 | anon_vma_interval_tree_pre_update_vma(next); | |
791 | } | |
012f1800 | 792 | |
1da177e4 LT |
793 | if (root) { |
794 | flush_dcache_mmap_lock(mapping); | |
6b2dbba8 | 795 | vma_interval_tree_remove(vma, root); |
1da177e4 | 796 | if (adjust_next) |
6b2dbba8 | 797 | vma_interval_tree_remove(next, root); |
1da177e4 LT |
798 | } |
799 | ||
d3737187 ML |
800 | if (start != vma->vm_start) { |
801 | vma->vm_start = start; | |
802 | start_changed = true; | |
803 | } | |
804 | if (end != vma->vm_end) { | |
805 | vma->vm_end = end; | |
806 | end_changed = true; | |
807 | } | |
1da177e4 LT |
808 | vma->vm_pgoff = pgoff; |
809 | if (adjust_next) { | |
810 | next->vm_start += adjust_next << PAGE_SHIFT; | |
811 | next->vm_pgoff += adjust_next; | |
812 | } | |
813 | ||
814 | if (root) { | |
815 | if (adjust_next) | |
6b2dbba8 ML |
816 | vma_interval_tree_insert(next, root); |
817 | vma_interval_tree_insert(vma, root); | |
1da177e4 LT |
818 | flush_dcache_mmap_unlock(mapping); |
819 | } | |
820 | ||
821 | if (remove_next) { | |
822 | /* | |
823 | * vma_merge has merged next into vma, and needs | |
824 | * us to remove next before dropping the locks. | |
825 | */ | |
826 | __vma_unlink(mm, next, vma); | |
827 | if (file) | |
828 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
829 | } else if (insert) { |
830 | /* | |
831 | * split_vma has split insert from vma, and needs | |
832 | * us to insert it before dropping the locks | |
833 | * (it may either follow vma or precede it). | |
834 | */ | |
835 | __insert_vm_struct(mm, insert); | |
d3737187 ML |
836 | } else { |
837 | if (start_changed) | |
838 | vma_gap_update(vma); | |
839 | if (end_changed) { | |
840 | if (!next) | |
841 | mm->highest_vm_end = end; | |
842 | else if (!adjust_next) | |
843 | vma_gap_update(next); | |
844 | } | |
1da177e4 LT |
845 | } |
846 | ||
bf181b9f ML |
847 | if (anon_vma) { |
848 | anon_vma_interval_tree_post_update_vma(vma); | |
849 | if (adjust_next) | |
850 | anon_vma_interval_tree_post_update_vma(next); | |
08b52706 | 851 | anon_vma_unlock_write(anon_vma); |
bf181b9f | 852 | } |
1da177e4 | 853 | if (mapping) |
3d48ae45 | 854 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 855 | |
2b144498 | 856 | if (root) { |
7b2d81d4 | 857 | uprobe_mmap(vma); |
2b144498 SD |
858 | |
859 | if (adjust_next) | |
7b2d81d4 | 860 | uprobe_mmap(next); |
2b144498 SD |
861 | } |
862 | ||
1da177e4 | 863 | if (remove_next) { |
925d1c40 | 864 | if (file) { |
cbc91f71 | 865 | uprobe_munmap(next, next->vm_start, next->vm_end); |
1da177e4 | 866 | fput(file); |
925d1c40 | 867 | } |
5beb4930 RR |
868 | if (next->anon_vma) |
869 | anon_vma_merge(vma, next); | |
1da177e4 | 870 | mm->map_count--; |
3964acd0 | 871 | mpol_put(vma_policy(next)); |
1da177e4 LT |
872 | kmem_cache_free(vm_area_cachep, next); |
873 | /* | |
874 | * In mprotect's case 6 (see comments on vma_merge), | |
875 | * we must remove another next too. It would clutter | |
876 | * up the code too much to do both in one go. | |
877 | */ | |
d3737187 ML |
878 | next = vma->vm_next; |
879 | if (remove_next == 2) | |
1da177e4 | 880 | goto again; |
d3737187 ML |
881 | else if (next) |
882 | vma_gap_update(next); | |
883 | else | |
884 | mm->highest_vm_end = end; | |
1da177e4 | 885 | } |
2b144498 | 886 | if (insert && file) |
7b2d81d4 | 887 | uprobe_mmap(insert); |
1da177e4 LT |
888 | |
889 | validate_mm(mm); | |
5beb4930 RR |
890 | |
891 | return 0; | |
1da177e4 LT |
892 | } |
893 | ||
894 | /* | |
895 | * If the vma has a ->close operation then the driver probably needs to release | |
896 | * per-vma resources, so we don't attempt to merge those. | |
897 | */ | |
1da177e4 LT |
898 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
899 | struct file *file, unsigned long vm_flags) | |
900 | { | |
34228d47 CG |
901 | /* |
902 | * VM_SOFTDIRTY should not prevent from VMA merging, if we | |
903 | * match the flags but dirty bit -- the caller should mark | |
904 | * merged VMA as dirty. If dirty bit won't be excluded from | |
905 | * comparison, we increase pressue on the memory system forcing | |
906 | * the kernel to generate new VMAs when old one could be | |
907 | * extended instead. | |
908 | */ | |
909 | if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) | |
1da177e4 LT |
910 | return 0; |
911 | if (vma->vm_file != file) | |
912 | return 0; | |
913 | if (vma->vm_ops && vma->vm_ops->close) | |
914 | return 0; | |
915 | return 1; | |
916 | } | |
917 | ||
918 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
919 | struct anon_vma *anon_vma2, |
920 | struct vm_area_struct *vma) | |
1da177e4 | 921 | { |
965f55de SL |
922 | /* |
923 | * The list_is_singular() test is to avoid merging VMA cloned from | |
924 | * parents. This can improve scalability caused by anon_vma lock. | |
925 | */ | |
926 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
927 | list_is_singular(&vma->anon_vma_chain))) | |
928 | return 1; | |
929 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
930 | } |
931 | ||
932 | /* | |
933 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
934 | * in front of (at a lower virtual address and file offset than) the vma. | |
935 | * | |
936 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
937 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
938 | * | |
939 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
940 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
941 | * wrap, nor mmaps which cover the final page at index -1UL. | |
942 | */ | |
943 | static int | |
944 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
945 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
946 | { | |
947 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 948 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
949 | if (vma->vm_pgoff == vm_pgoff) |
950 | return 1; | |
951 | } | |
952 | return 0; | |
953 | } | |
954 | ||
955 | /* | |
956 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
957 | * beyond (at a higher virtual address and file offset than) the vma. | |
958 | * | |
959 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
960 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
961 | */ | |
962 | static int | |
963 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
964 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
965 | { | |
966 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 967 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 | 968 | pgoff_t vm_pglen; |
d6e93217 | 969 | vm_pglen = vma_pages(vma); |
1da177e4 LT |
970 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
971 | return 1; | |
972 | } | |
973 | return 0; | |
974 | } | |
975 | ||
976 | /* | |
977 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
978 | * whether that can be merged with its predecessor or its successor. | |
979 | * Or both (it neatly fills a hole). | |
980 | * | |
981 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
982 | * certain not to be mapped by the time vma_merge is called; but when | |
983 | * called for mprotect, it is certain to be already mapped (either at | |
984 | * an offset within prev, or at the start of next), and the flags of | |
985 | * this area are about to be changed to vm_flags - and the no-change | |
986 | * case has already been eliminated. | |
987 | * | |
988 | * The following mprotect cases have to be considered, where AAAA is | |
989 | * the area passed down from mprotect_fixup, never extending beyond one | |
990 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
991 | * | |
992 | * AAAA AAAA AAAA AAAA | |
993 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
994 | * cannot merge might become might become might become | |
995 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
996 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
997 | * mremap move: PPPPNNNNNNNN 8 | |
998 | * AAAA | |
999 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
1000 | * might become case 1 below case 2 below case 3 below | |
1001 | * | |
1002 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
1003 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
1004 | */ | |
1005 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
1006 | struct vm_area_struct *prev, unsigned long addr, | |
1007 | unsigned long end, unsigned long vm_flags, | |
1008 | struct anon_vma *anon_vma, struct file *file, | |
1009 | pgoff_t pgoff, struct mempolicy *policy) | |
1010 | { | |
1011 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
1012 | struct vm_area_struct *area, *next; | |
5beb4930 | 1013 | int err; |
1da177e4 LT |
1014 | |
1015 | /* | |
1016 | * We later require that vma->vm_flags == vm_flags, | |
1017 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
1018 | */ | |
1019 | if (vm_flags & VM_SPECIAL) | |
1020 | return NULL; | |
1021 | ||
1022 | if (prev) | |
1023 | next = prev->vm_next; | |
1024 | else | |
1025 | next = mm->mmap; | |
1026 | area = next; | |
1027 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
1028 | next = next->vm_next; | |
1029 | ||
1030 | /* | |
1031 | * Can it merge with the predecessor? | |
1032 | */ | |
1033 | if (prev && prev->vm_end == addr && | |
1034 | mpol_equal(vma_policy(prev), policy) && | |
1035 | can_vma_merge_after(prev, vm_flags, | |
1036 | anon_vma, file, pgoff)) { | |
1037 | /* | |
1038 | * OK, it can. Can we now merge in the successor as well? | |
1039 | */ | |
1040 | if (next && end == next->vm_start && | |
1041 | mpol_equal(policy, vma_policy(next)) && | |
1042 | can_vma_merge_before(next, vm_flags, | |
1043 | anon_vma, file, pgoff+pglen) && | |
1044 | is_mergeable_anon_vma(prev->anon_vma, | |
965f55de | 1045 | next->anon_vma, NULL)) { |
1da177e4 | 1046 | /* cases 1, 6 */ |
5beb4930 | 1047 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
1048 | next->vm_end, prev->vm_pgoff, NULL); |
1049 | } else /* cases 2, 5, 7 */ | |
5beb4930 | 1050 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 | 1051 | end, prev->vm_pgoff, NULL); |
5beb4930 RR |
1052 | if (err) |
1053 | return NULL; | |
b15d00b6 | 1054 | khugepaged_enter_vma_merge(prev); |
1da177e4 LT |
1055 | return prev; |
1056 | } | |
1057 | ||
1058 | /* | |
1059 | * Can this new request be merged in front of next? | |
1060 | */ | |
1061 | if (next && end == next->vm_start && | |
1062 | mpol_equal(policy, vma_policy(next)) && | |
1063 | can_vma_merge_before(next, vm_flags, | |
1064 | anon_vma, file, pgoff+pglen)) { | |
1065 | if (prev && addr < prev->vm_end) /* case 4 */ | |
5beb4930 | 1066 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
1067 | addr, prev->vm_pgoff, NULL); |
1068 | else /* cases 3, 8 */ | |
5beb4930 | 1069 | err = vma_adjust(area, addr, next->vm_end, |
1da177e4 | 1070 | next->vm_pgoff - pglen, NULL); |
5beb4930 RR |
1071 | if (err) |
1072 | return NULL; | |
b15d00b6 | 1073 | khugepaged_enter_vma_merge(area); |
1da177e4 LT |
1074 | return area; |
1075 | } | |
1076 | ||
1077 | return NULL; | |
1078 | } | |
1079 | ||
d0e9fe17 LT |
1080 | /* |
1081 | * Rough compatbility check to quickly see if it's even worth looking | |
1082 | * at sharing an anon_vma. | |
1083 | * | |
1084 | * They need to have the same vm_file, and the flags can only differ | |
1085 | * in things that mprotect may change. | |
1086 | * | |
1087 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
1088 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
1089 | * there is a vm_ops->close() function, because that indicates that the | |
1090 | * driver is doing some kind of reference counting. But that doesn't | |
1091 | * really matter for the anon_vma sharing case. | |
1092 | */ | |
1093 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
1094 | { | |
1095 | return a->vm_end == b->vm_start && | |
1096 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
1097 | a->vm_file == b->vm_file && | |
34228d47 | 1098 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) && |
d0e9fe17 LT |
1099 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); |
1100 | } | |
1101 | ||
1102 | /* | |
1103 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
1104 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
1105 | * the same as 'old', the other will be the new one that is trying | |
1106 | * to share the anon_vma. | |
1107 | * | |
1108 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
1109 | * the anon_vma of 'old' is concurrently in the process of being set up | |
1110 | * by another page fault trying to merge _that_. But that's ok: if it | |
1111 | * is being set up, that automatically means that it will be a singleton | |
1112 | * acceptable for merging, so we can do all of this optimistically. But | |
1113 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. | |
1114 | * | |
1115 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
1116 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
1117 | * is to return an anon_vma that is "complex" due to having gone through | |
1118 | * a fork). | |
1119 | * | |
1120 | * We also make sure that the two vma's are compatible (adjacent, | |
1121 | * and with the same memory policies). That's all stable, even with just | |
1122 | * a read lock on the mm_sem. | |
1123 | */ | |
1124 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
1125 | { | |
1126 | if (anon_vma_compatible(a, b)) { | |
1127 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); | |
1128 | ||
1129 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
1130 | return anon_vma; | |
1131 | } | |
1132 | return NULL; | |
1133 | } | |
1134 | ||
1da177e4 LT |
1135 | /* |
1136 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
1137 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
1138 | * to allocate a new anon_vma. It checks because a repetitive | |
1139 | * sequence of mprotects and faults may otherwise lead to distinct | |
1140 | * anon_vmas being allocated, preventing vma merge in subsequent | |
1141 | * mprotect. | |
1142 | */ | |
1143 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
1144 | { | |
d0e9fe17 | 1145 | struct anon_vma *anon_vma; |
1da177e4 | 1146 | struct vm_area_struct *near; |
1da177e4 LT |
1147 | |
1148 | near = vma->vm_next; | |
1149 | if (!near) | |
1150 | goto try_prev; | |
1151 | ||
d0e9fe17 LT |
1152 | anon_vma = reusable_anon_vma(near, vma, near); |
1153 | if (anon_vma) | |
1154 | return anon_vma; | |
1da177e4 | 1155 | try_prev: |
9be34c9d | 1156 | near = vma->vm_prev; |
1da177e4 LT |
1157 | if (!near) |
1158 | goto none; | |
1159 | ||
d0e9fe17 LT |
1160 | anon_vma = reusable_anon_vma(near, near, vma); |
1161 | if (anon_vma) | |
1162 | return anon_vma; | |
1da177e4 LT |
1163 | none: |
1164 | /* | |
1165 | * There's no absolute need to look only at touching neighbours: | |
1166 | * we could search further afield for "compatible" anon_vmas. | |
1167 | * But it would probably just be a waste of time searching, | |
1168 | * or lead to too many vmas hanging off the same anon_vma. | |
1169 | * We're trying to allow mprotect remerging later on, | |
1170 | * not trying to minimize memory used for anon_vmas. | |
1171 | */ | |
1172 | return NULL; | |
1173 | } | |
1174 | ||
1175 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 1176 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
1177 | struct file *file, long pages) |
1178 | { | |
1179 | const unsigned long stack_flags | |
1180 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
1181 | ||
44de9d0c HS |
1182 | mm->total_vm += pages; |
1183 | ||
1da177e4 LT |
1184 | if (file) { |
1185 | mm->shared_vm += pages; | |
1186 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
1187 | mm->exec_vm += pages; | |
1188 | } else if (flags & stack_flags) | |
1189 | mm->stack_vm += pages; | |
1da177e4 LT |
1190 | } |
1191 | #endif /* CONFIG_PROC_FS */ | |
1192 | ||
40401530 AV |
1193 | /* |
1194 | * If a hint addr is less than mmap_min_addr change hint to be as | |
1195 | * low as possible but still greater than mmap_min_addr | |
1196 | */ | |
1197 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
1198 | { | |
1199 | hint &= PAGE_MASK; | |
1200 | if (((void *)hint != NULL) && | |
1201 | (hint < mmap_min_addr)) | |
1202 | return PAGE_ALIGN(mmap_min_addr); | |
1203 | return hint; | |
1204 | } | |
1205 | ||
363ee17f DB |
1206 | static inline int mlock_future_check(struct mm_struct *mm, |
1207 | unsigned long flags, | |
1208 | unsigned long len) | |
1209 | { | |
1210 | unsigned long locked, lock_limit; | |
1211 | ||
1212 | /* mlock MCL_FUTURE? */ | |
1213 | if (flags & VM_LOCKED) { | |
1214 | locked = len >> PAGE_SHIFT; | |
1215 | locked += mm->locked_vm; | |
1216 | lock_limit = rlimit(RLIMIT_MEMLOCK); | |
1217 | lock_limit >>= PAGE_SHIFT; | |
1218 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) | |
1219 | return -EAGAIN; | |
1220 | } | |
1221 | return 0; | |
1222 | } | |
1223 | ||
1da177e4 | 1224 | /* |
27f5de79 | 1225 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
1226 | */ |
1227 | ||
e3fc629d | 1228 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 | 1229 | unsigned long len, unsigned long prot, |
bebeb3d6 | 1230 | unsigned long flags, unsigned long pgoff, |
41badc15 | 1231 | unsigned long *populate) |
1da177e4 LT |
1232 | { |
1233 | struct mm_struct * mm = current->mm; | |
ca16d140 | 1234 | vm_flags_t vm_flags; |
1da177e4 | 1235 | |
41badc15 | 1236 | *populate = 0; |
bebeb3d6 | 1237 | |
1da177e4 LT |
1238 | /* |
1239 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
1240 | * | |
1241 | * (the exception is when the underlying filesystem is noexec | |
1242 | * mounted, in which case we dont add PROT_EXEC.) | |
1243 | */ | |
1244 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 1245 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
1246 | prot |= PROT_EXEC; |
1247 | ||
1248 | if (!len) | |
1249 | return -EINVAL; | |
1250 | ||
7cd94146 EP |
1251 | if (!(flags & MAP_FIXED)) |
1252 | addr = round_hint_to_min(addr); | |
1253 | ||
1da177e4 LT |
1254 | /* Careful about overflows.. */ |
1255 | len = PAGE_ALIGN(len); | |
9206de95 | 1256 | if (!len) |
1da177e4 LT |
1257 | return -ENOMEM; |
1258 | ||
1259 | /* offset overflow? */ | |
1260 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
1261 | return -EOVERFLOW; | |
1262 | ||
1263 | /* Too many mappings? */ | |
1264 | if (mm->map_count > sysctl_max_map_count) | |
1265 | return -ENOMEM; | |
1266 | ||
1267 | /* Obtain the address to map to. we verify (or select) it and ensure | |
1268 | * that it represents a valid section of the address space. | |
1269 | */ | |
1270 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
1271 | if (addr & ~PAGE_MASK) | |
1272 | return addr; | |
1273 | ||
1274 | /* Do simple checking here so the lower-level routines won't have | |
1275 | * to. we assume access permissions have been handled by the open | |
1276 | * of the memory object, so we don't do any here. | |
1277 | */ | |
1278 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
1279 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
1280 | ||
cdf7b341 | 1281 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1282 | if (!can_do_mlock()) |
1283 | return -EPERM; | |
ba470de4 | 1284 | |
363ee17f DB |
1285 | if (mlock_future_check(mm, vm_flags, len)) |
1286 | return -EAGAIN; | |
1da177e4 | 1287 | |
1da177e4 | 1288 | if (file) { |
077bf22b ON |
1289 | struct inode *inode = file_inode(file); |
1290 | ||
1da177e4 LT |
1291 | switch (flags & MAP_TYPE) { |
1292 | case MAP_SHARED: | |
1293 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1294 | return -EACCES; | |
1295 | ||
1296 | /* | |
1297 | * Make sure we don't allow writing to an append-only | |
1298 | * file.. | |
1299 | */ | |
1300 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1301 | return -EACCES; | |
1302 | ||
1303 | /* | |
1304 | * Make sure there are no mandatory locks on the file. | |
1305 | */ | |
d7a06983 | 1306 | if (locks_verify_locked(file)) |
1da177e4 LT |
1307 | return -EAGAIN; |
1308 | ||
1309 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1310 | if (!(file->f_mode & FMODE_WRITE)) | |
1311 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1312 | ||
1313 | /* fall through */ | |
1314 | case MAP_PRIVATE: | |
1315 | if (!(file->f_mode & FMODE_READ)) | |
1316 | return -EACCES; | |
d3ac7f89 | 1317 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1318 | if (vm_flags & VM_EXEC) |
1319 | return -EPERM; | |
1320 | vm_flags &= ~VM_MAYEXEC; | |
1321 | } | |
80c5606c | 1322 | |
72c2d531 | 1323 | if (!file->f_op->mmap) |
80c5606c | 1324 | return -ENODEV; |
b2c56e4f ON |
1325 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1326 | return -EINVAL; | |
1da177e4 LT |
1327 | break; |
1328 | ||
1329 | default: | |
1330 | return -EINVAL; | |
1331 | } | |
1332 | } else { | |
1333 | switch (flags & MAP_TYPE) { | |
1334 | case MAP_SHARED: | |
b2c56e4f ON |
1335 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1336 | return -EINVAL; | |
ce363942 TH |
1337 | /* |
1338 | * Ignore pgoff. | |
1339 | */ | |
1340 | pgoff = 0; | |
1da177e4 LT |
1341 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1342 | break; | |
1343 | case MAP_PRIVATE: | |
1344 | /* | |
1345 | * Set pgoff according to addr for anon_vma. | |
1346 | */ | |
1347 | pgoff = addr >> PAGE_SHIFT; | |
1348 | break; | |
1349 | default: | |
1350 | return -EINVAL; | |
1351 | } | |
1352 | } | |
1353 | ||
c22c0d63 ML |
1354 | /* |
1355 | * Set 'VM_NORESERVE' if we should not account for the | |
1356 | * memory use of this mapping. | |
1357 | */ | |
1358 | if (flags & MAP_NORESERVE) { | |
1359 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1360 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1361 | vm_flags |= VM_NORESERVE; | |
1362 | ||
1363 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1364 | if (file && is_file_hugepages(file)) | |
1365 | vm_flags |= VM_NORESERVE; | |
1366 | } | |
1367 | ||
1368 | addr = mmap_region(file, addr, len, vm_flags, pgoff); | |
09a9f1d2 ML |
1369 | if (!IS_ERR_VALUE(addr) && |
1370 | ((vm_flags & VM_LOCKED) || | |
1371 | (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) | |
41badc15 | 1372 | *populate = len; |
bebeb3d6 | 1373 | return addr; |
0165ab44 | 1374 | } |
6be5ceb0 | 1375 | |
66f0dc48 HD |
1376 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1377 | unsigned long, prot, unsigned long, flags, | |
1378 | unsigned long, fd, unsigned long, pgoff) | |
1379 | { | |
1380 | struct file *file = NULL; | |
1381 | unsigned long retval = -EBADF; | |
1382 | ||
1383 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1384 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1385 | file = fget(fd); |
1386 | if (!file) | |
1387 | goto out; | |
af73e4d9 NH |
1388 | if (is_file_hugepages(file)) |
1389 | len = ALIGN(len, huge_page_size(hstate_file(file))); | |
493af578 JE |
1390 | retval = -EINVAL; |
1391 | if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) | |
1392 | goto out_fput; | |
66f0dc48 HD |
1393 | } else if (flags & MAP_HUGETLB) { |
1394 | struct user_struct *user = NULL; | |
c103a4dc | 1395 | struct hstate *hs; |
af73e4d9 | 1396 | |
c103a4dc | 1397 | hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK); |
091d0d55 LZ |
1398 | if (!hs) |
1399 | return -EINVAL; | |
1400 | ||
1401 | len = ALIGN(len, huge_page_size(hs)); | |
66f0dc48 HD |
1402 | /* |
1403 | * VM_NORESERVE is used because the reservations will be | |
1404 | * taken when vm_ops->mmap() is called | |
1405 | * A dummy user value is used because we are not locking | |
1406 | * memory so no accounting is necessary | |
1407 | */ | |
af73e4d9 | 1408 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, |
42d7395f AK |
1409 | VM_NORESERVE, |
1410 | &user, HUGETLB_ANONHUGE_INODE, | |
1411 | (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); | |
66f0dc48 HD |
1412 | if (IS_ERR(file)) |
1413 | return PTR_ERR(file); | |
1414 | } | |
1415 | ||
1416 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1417 | ||
eb36c587 | 1418 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
493af578 | 1419 | out_fput: |
66f0dc48 HD |
1420 | if (file) |
1421 | fput(file); | |
1422 | out: | |
1423 | return retval; | |
1424 | } | |
1425 | ||
a4679373 CH |
1426 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1427 | struct mmap_arg_struct { | |
1428 | unsigned long addr; | |
1429 | unsigned long len; | |
1430 | unsigned long prot; | |
1431 | unsigned long flags; | |
1432 | unsigned long fd; | |
1433 | unsigned long offset; | |
1434 | }; | |
1435 | ||
1436 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1437 | { | |
1438 | struct mmap_arg_struct a; | |
1439 | ||
1440 | if (copy_from_user(&a, arg, sizeof(a))) | |
1441 | return -EFAULT; | |
1442 | if (a.offset & ~PAGE_MASK) | |
1443 | return -EINVAL; | |
1444 | ||
1445 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1446 | a.offset >> PAGE_SHIFT); | |
1447 | } | |
1448 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1449 | ||
4e950f6f AD |
1450 | /* |
1451 | * Some shared mappigns will want the pages marked read-only | |
1452 | * to track write events. If so, we'll downgrade vm_page_prot | |
1453 | * to the private version (using protection_map[] without the | |
1454 | * VM_SHARED bit). | |
1455 | */ | |
1456 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1457 | { | |
ca16d140 | 1458 | vm_flags_t vm_flags = vma->vm_flags; |
4e950f6f AD |
1459 | |
1460 | /* If it was private or non-writable, the write bit is already clear */ | |
1461 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1462 | return 0; | |
1463 | ||
1464 | /* The backer wishes to know when pages are first written to? */ | |
1465 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1466 | return 1; | |
1467 | ||
1468 | /* The open routine did something to the protections already? */ | |
1469 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1470 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1471 | return 0; |
1472 | ||
1473 | /* Specialty mapping? */ | |
4b6e1e37 | 1474 | if (vm_flags & VM_PFNMAP) |
4e950f6f AD |
1475 | return 0; |
1476 | ||
1477 | /* Can the mapping track the dirty pages? */ | |
1478 | return vma->vm_file && vma->vm_file->f_mapping && | |
1479 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1480 | } | |
1481 | ||
fc8744ad LT |
1482 | /* |
1483 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1484 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1485 | */ |
ca16d140 | 1486 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1487 | { |
5a6fe125 MG |
1488 | /* |
1489 | * hugetlb has its own accounting separate from the core VM | |
1490 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1491 | */ | |
1492 | if (file && is_file_hugepages(file)) | |
1493 | return 0; | |
1494 | ||
fc8744ad LT |
1495 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1496 | } | |
1497 | ||
0165ab44 | 1498 | unsigned long mmap_region(struct file *file, unsigned long addr, |
c22c0d63 | 1499 | unsigned long len, vm_flags_t vm_flags, unsigned long pgoff) |
0165ab44 MS |
1500 | { |
1501 | struct mm_struct *mm = current->mm; | |
1502 | struct vm_area_struct *vma, *prev; | |
0165ab44 MS |
1503 | int error; |
1504 | struct rb_node **rb_link, *rb_parent; | |
1505 | unsigned long charged = 0; | |
0165ab44 | 1506 | |
e8420a8e CH |
1507 | /* Check against address space limit. */ |
1508 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) { | |
1509 | unsigned long nr_pages; | |
1510 | ||
1511 | /* | |
1512 | * MAP_FIXED may remove pages of mappings that intersects with | |
1513 | * requested mapping. Account for the pages it would unmap. | |
1514 | */ | |
1515 | if (!(vm_flags & MAP_FIXED)) | |
1516 | return -ENOMEM; | |
1517 | ||
1518 | nr_pages = count_vma_pages_range(mm, addr, addr + len); | |
1519 | ||
1520 | if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages)) | |
1521 | return -ENOMEM; | |
1522 | } | |
1523 | ||
1da177e4 LT |
1524 | /* Clear old maps */ |
1525 | error = -ENOMEM; | |
1526 | munmap_back: | |
6597d783 | 1527 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
1528 | if (do_munmap(mm, addr, len)) |
1529 | return -ENOMEM; | |
1530 | goto munmap_back; | |
1531 | } | |
1532 | ||
fc8744ad LT |
1533 | /* |
1534 | * Private writable mapping: check memory availability | |
1535 | */ | |
5a6fe125 | 1536 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1537 | charged = len >> PAGE_SHIFT; |
191c5424 | 1538 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1539 | return -ENOMEM; |
1540 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1541 | } |
1542 | ||
1543 | /* | |
de33c8db | 1544 | * Can we just expand an old mapping? |
1da177e4 | 1545 | */ |
de33c8db LT |
1546 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1547 | if (vma) | |
1548 | goto out; | |
1da177e4 LT |
1549 | |
1550 | /* | |
1551 | * Determine the object being mapped and call the appropriate | |
1552 | * specific mapper. the address has already been validated, but | |
1553 | * not unmapped, but the maps are removed from the list. | |
1554 | */ | |
c5e3b83e | 1555 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1556 | if (!vma) { |
1557 | error = -ENOMEM; | |
1558 | goto unacct_error; | |
1559 | } | |
1da177e4 LT |
1560 | |
1561 | vma->vm_mm = mm; | |
1562 | vma->vm_start = addr; | |
1563 | vma->vm_end = addr + len; | |
1564 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1565 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1566 | vma->vm_pgoff = pgoff; |
5beb4930 | 1567 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
1568 | |
1569 | if (file) { | |
1da177e4 LT |
1570 | if (vm_flags & VM_DENYWRITE) { |
1571 | error = deny_write_access(file); | |
1572 | if (error) | |
1573 | goto free_vma; | |
1da177e4 | 1574 | } |
cb0942b8 | 1575 | vma->vm_file = get_file(file); |
1da177e4 LT |
1576 | error = file->f_op->mmap(file, vma); |
1577 | if (error) | |
1578 | goto unmap_and_free_vma; | |
f8dbf0a7 HS |
1579 | |
1580 | /* Can addr have changed?? | |
1581 | * | |
1582 | * Answer: Yes, several device drivers can do it in their | |
1583 | * f_op->mmap method. -DaveM | |
2897b4d2 JK |
1584 | * Bug: If addr is changed, prev, rb_link, rb_parent should |
1585 | * be updated for vma_link() | |
f8dbf0a7 | 1586 | */ |
2897b4d2 JK |
1587 | WARN_ON_ONCE(addr != vma->vm_start); |
1588 | ||
f8dbf0a7 | 1589 | addr = vma->vm_start; |
f8dbf0a7 | 1590 | vm_flags = vma->vm_flags; |
1da177e4 LT |
1591 | } else if (vm_flags & VM_SHARED) { |
1592 | error = shmem_zero_setup(vma); | |
1593 | if (error) | |
1594 | goto free_vma; | |
1595 | } | |
1596 | ||
c9d0bf24 MD |
1597 | if (vma_wants_writenotify(vma)) { |
1598 | pgprot_t pprot = vma->vm_page_prot; | |
1599 | ||
1600 | /* Can vma->vm_page_prot have changed?? | |
1601 | * | |
1602 | * Answer: Yes, drivers may have changed it in their | |
1603 | * f_op->mmap method. | |
1604 | * | |
1605 | * Ensures that vmas marked as uncached stay that way. | |
1606 | */ | |
1ddd439e | 1607 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
c9d0bf24 MD |
1608 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
1609 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
1610 | } | |
d08b3851 | 1611 | |
de33c8db | 1612 | vma_link(mm, vma, prev, rb_link, rb_parent); |
4d3d5b41 | 1613 | /* Once vma denies write, undo our temporary denial count */ |
e8686772 ON |
1614 | if (vm_flags & VM_DENYWRITE) |
1615 | allow_write_access(file); | |
1616 | file = vma->vm_file; | |
4d3d5b41 | 1617 | out: |
cdd6c482 | 1618 | perf_event_mmap(vma); |
0a4a9391 | 1619 | |
ab50b8ed | 1620 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1621 | if (vm_flags & VM_LOCKED) { |
bebeb3d6 ML |
1622 | if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || |
1623 | vma == get_gate_vma(current->mm))) | |
06f9d8c2 | 1624 | mm->locked_vm += (len >> PAGE_SHIFT); |
bebeb3d6 ML |
1625 | else |
1626 | vma->vm_flags &= ~VM_LOCKED; | |
1627 | } | |
2b144498 | 1628 | |
c7a3a88c ON |
1629 | if (file) |
1630 | uprobe_mmap(vma); | |
2b144498 | 1631 | |
d9104d1c CG |
1632 | /* |
1633 | * New (or expanded) vma always get soft dirty status. | |
1634 | * Otherwise user-space soft-dirty page tracker won't | |
1635 | * be able to distinguish situation when vma area unmapped, | |
1636 | * then new mapped in-place (which must be aimed as | |
1637 | * a completely new data area). | |
1638 | */ | |
1639 | vma->vm_flags |= VM_SOFTDIRTY; | |
1640 | ||
1da177e4 LT |
1641 | return addr; |
1642 | ||
1643 | unmap_and_free_vma: | |
e8686772 ON |
1644 | if (vm_flags & VM_DENYWRITE) |
1645 | allow_write_access(file); | |
1da177e4 LT |
1646 | vma->vm_file = NULL; |
1647 | fput(file); | |
1648 | ||
1649 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1650 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1651 | charged = 0; | |
1da177e4 LT |
1652 | free_vma: |
1653 | kmem_cache_free(vm_area_cachep, vma); | |
1654 | unacct_error: | |
1655 | if (charged) | |
1656 | vm_unacct_memory(charged); | |
1657 | return error; | |
1658 | } | |
1659 | ||
db4fbfb9 ML |
1660 | unsigned long unmapped_area(struct vm_unmapped_area_info *info) |
1661 | { | |
1662 | /* | |
1663 | * We implement the search by looking for an rbtree node that | |
1664 | * immediately follows a suitable gap. That is, | |
1665 | * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; | |
1666 | * - gap_end = vma->vm_start >= info->low_limit + length; | |
1667 | * - gap_end - gap_start >= length | |
1668 | */ | |
1669 | ||
1670 | struct mm_struct *mm = current->mm; | |
1671 | struct vm_area_struct *vma; | |
1672 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1673 | ||
1674 | /* Adjust search length to account for worst case alignment overhead */ | |
1675 | length = info->length + info->align_mask; | |
1676 | if (length < info->length) | |
1677 | return -ENOMEM; | |
1678 | ||
1679 | /* Adjust search limits by the desired length */ | |
1680 | if (info->high_limit < length) | |
1681 | return -ENOMEM; | |
1682 | high_limit = info->high_limit - length; | |
1683 | ||
1684 | if (info->low_limit > high_limit) | |
1685 | return -ENOMEM; | |
1686 | low_limit = info->low_limit + length; | |
1687 | ||
1688 | /* Check if rbtree root looks promising */ | |
1689 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1690 | goto check_highest; | |
1691 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1692 | if (vma->rb_subtree_gap < length) | |
1693 | goto check_highest; | |
1694 | ||
1695 | while (true) { | |
1696 | /* Visit left subtree if it looks promising */ | |
1697 | gap_end = vma->vm_start; | |
1698 | if (gap_end >= low_limit && vma->vm_rb.rb_left) { | |
1699 | struct vm_area_struct *left = | |
1700 | rb_entry(vma->vm_rb.rb_left, | |
1701 | struct vm_area_struct, vm_rb); | |
1702 | if (left->rb_subtree_gap >= length) { | |
1703 | vma = left; | |
1704 | continue; | |
1705 | } | |
1706 | } | |
1707 | ||
1708 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; | |
1709 | check_current: | |
1710 | /* Check if current node has a suitable gap */ | |
1711 | if (gap_start > high_limit) | |
1712 | return -ENOMEM; | |
1713 | if (gap_end >= low_limit && gap_end - gap_start >= length) | |
1714 | goto found; | |
1715 | ||
1716 | /* Visit right subtree if it looks promising */ | |
1717 | if (vma->vm_rb.rb_right) { | |
1718 | struct vm_area_struct *right = | |
1719 | rb_entry(vma->vm_rb.rb_right, | |
1720 | struct vm_area_struct, vm_rb); | |
1721 | if (right->rb_subtree_gap >= length) { | |
1722 | vma = right; | |
1723 | continue; | |
1724 | } | |
1725 | } | |
1726 | ||
1727 | /* Go back up the rbtree to find next candidate node */ | |
1728 | while (true) { | |
1729 | struct rb_node *prev = &vma->vm_rb; | |
1730 | if (!rb_parent(prev)) | |
1731 | goto check_highest; | |
1732 | vma = rb_entry(rb_parent(prev), | |
1733 | struct vm_area_struct, vm_rb); | |
1734 | if (prev == vma->vm_rb.rb_left) { | |
1735 | gap_start = vma->vm_prev->vm_end; | |
1736 | gap_end = vma->vm_start; | |
1737 | goto check_current; | |
1738 | } | |
1739 | } | |
1740 | } | |
1741 | ||
1742 | check_highest: | |
1743 | /* Check highest gap, which does not precede any rbtree node */ | |
1744 | gap_start = mm->highest_vm_end; | |
1745 | gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ | |
1746 | if (gap_start > high_limit) | |
1747 | return -ENOMEM; | |
1748 | ||
1749 | found: | |
1750 | /* We found a suitable gap. Clip it with the original low_limit. */ | |
1751 | if (gap_start < info->low_limit) | |
1752 | gap_start = info->low_limit; | |
1753 | ||
1754 | /* Adjust gap address to the desired alignment */ | |
1755 | gap_start += (info->align_offset - gap_start) & info->align_mask; | |
1756 | ||
1757 | VM_BUG_ON(gap_start + info->length > info->high_limit); | |
1758 | VM_BUG_ON(gap_start + info->length > gap_end); | |
1759 | return gap_start; | |
1760 | } | |
1761 | ||
1762 | unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) | |
1763 | { | |
1764 | struct mm_struct *mm = current->mm; | |
1765 | struct vm_area_struct *vma; | |
1766 | unsigned long length, low_limit, high_limit, gap_start, gap_end; | |
1767 | ||
1768 | /* Adjust search length to account for worst case alignment overhead */ | |
1769 | length = info->length + info->align_mask; | |
1770 | if (length < info->length) | |
1771 | return -ENOMEM; | |
1772 | ||
1773 | /* | |
1774 | * Adjust search limits by the desired length. | |
1775 | * See implementation comment at top of unmapped_area(). | |
1776 | */ | |
1777 | gap_end = info->high_limit; | |
1778 | if (gap_end < length) | |
1779 | return -ENOMEM; | |
1780 | high_limit = gap_end - length; | |
1781 | ||
1782 | if (info->low_limit > high_limit) | |
1783 | return -ENOMEM; | |
1784 | low_limit = info->low_limit + length; | |
1785 | ||
1786 | /* Check highest gap, which does not precede any rbtree node */ | |
1787 | gap_start = mm->highest_vm_end; | |
1788 | if (gap_start <= high_limit) | |
1789 | goto found_highest; | |
1790 | ||
1791 | /* Check if rbtree root looks promising */ | |
1792 | if (RB_EMPTY_ROOT(&mm->mm_rb)) | |
1793 | return -ENOMEM; | |
1794 | vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); | |
1795 | if (vma->rb_subtree_gap < length) | |
1796 | return -ENOMEM; | |
1797 | ||
1798 | while (true) { | |
1799 | /* Visit right subtree if it looks promising */ | |
1800 | gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; | |
1801 | if (gap_start <= high_limit && vma->vm_rb.rb_right) { | |
1802 | struct vm_area_struct *right = | |
1803 | rb_entry(vma->vm_rb.rb_right, | |
1804 | struct vm_area_struct, vm_rb); | |
1805 | if (right->rb_subtree_gap >= length) { | |
1806 | vma = right; | |
1807 | continue; | |
1808 | } | |
1809 | } | |
1810 | ||
1811 | check_current: | |
1812 | /* Check if current node has a suitable gap */ | |
1813 | gap_end = vma->vm_start; | |
1814 | if (gap_end < low_limit) | |
1815 | return -ENOMEM; | |
1816 | if (gap_start <= high_limit && gap_end - gap_start >= length) | |
1817 | goto found; | |
1818 | ||
1819 | /* Visit left subtree if it looks promising */ | |
1820 | if (vma->vm_rb.rb_left) { | |
1821 | struct vm_area_struct *left = | |
1822 | rb_entry(vma->vm_rb.rb_left, | |
1823 | struct vm_area_struct, vm_rb); | |
1824 | if (left->rb_subtree_gap >= length) { | |
1825 | vma = left; | |
1826 | continue; | |
1827 | } | |
1828 | } | |
1829 | ||
1830 | /* Go back up the rbtree to find next candidate node */ | |
1831 | while (true) { | |
1832 | struct rb_node *prev = &vma->vm_rb; | |
1833 | if (!rb_parent(prev)) | |
1834 | return -ENOMEM; | |
1835 | vma = rb_entry(rb_parent(prev), | |
1836 | struct vm_area_struct, vm_rb); | |
1837 | if (prev == vma->vm_rb.rb_right) { | |
1838 | gap_start = vma->vm_prev ? | |
1839 | vma->vm_prev->vm_end : 0; | |
1840 | goto check_current; | |
1841 | } | |
1842 | } | |
1843 | } | |
1844 | ||
1845 | found: | |
1846 | /* We found a suitable gap. Clip it with the original high_limit. */ | |
1847 | if (gap_end > info->high_limit) | |
1848 | gap_end = info->high_limit; | |
1849 | ||
1850 | found_highest: | |
1851 | /* Compute highest gap address at the desired alignment */ | |
1852 | gap_end -= info->length; | |
1853 | gap_end -= (gap_end - info->align_offset) & info->align_mask; | |
1854 | ||
1855 | VM_BUG_ON(gap_end < info->low_limit); | |
1856 | VM_BUG_ON(gap_end < gap_start); | |
1857 | return gap_end; | |
1858 | } | |
1859 | ||
1da177e4 LT |
1860 | /* Get an address range which is currently unmapped. |
1861 | * For shmat() with addr=0. | |
1862 | * | |
1863 | * Ugly calling convention alert: | |
1864 | * Return value with the low bits set means error value, | |
1865 | * ie | |
1866 | * if (ret & ~PAGE_MASK) | |
1867 | * error = ret; | |
1868 | * | |
1869 | * This function "knows" that -ENOMEM has the bits set. | |
1870 | */ | |
1871 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1872 | unsigned long | |
1873 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1874 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1875 | { | |
1876 | struct mm_struct *mm = current->mm; | |
1877 | struct vm_area_struct *vma; | |
db4fbfb9 | 1878 | struct vm_unmapped_area_info info; |
1da177e4 | 1879 | |
2afc745f | 1880 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
1881 | return -ENOMEM; |
1882 | ||
06abdfb4 BH |
1883 | if (flags & MAP_FIXED) |
1884 | return addr; | |
1885 | ||
1da177e4 LT |
1886 | if (addr) { |
1887 | addr = PAGE_ALIGN(addr); | |
1888 | vma = find_vma(mm, addr); | |
2afc745f | 1889 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1da177e4 LT |
1890 | (!vma || addr + len <= vma->vm_start)) |
1891 | return addr; | |
1892 | } | |
1da177e4 | 1893 | |
db4fbfb9 ML |
1894 | info.flags = 0; |
1895 | info.length = len; | |
4e99b021 | 1896 | info.low_limit = mm->mmap_base; |
db4fbfb9 ML |
1897 | info.high_limit = TASK_SIZE; |
1898 | info.align_mask = 0; | |
1899 | return vm_unmapped_area(&info); | |
1da177e4 LT |
1900 | } |
1901 | #endif | |
1902 | ||
1da177e4 LT |
1903 | /* |
1904 | * This mmap-allocator allocates new areas top-down from below the | |
1905 | * stack's low limit (the base): | |
1906 | */ | |
1907 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1908 | unsigned long | |
1909 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1910 | const unsigned long len, const unsigned long pgoff, | |
1911 | const unsigned long flags) | |
1912 | { | |
1913 | struct vm_area_struct *vma; | |
1914 | struct mm_struct *mm = current->mm; | |
db4fbfb9 ML |
1915 | unsigned long addr = addr0; |
1916 | struct vm_unmapped_area_info info; | |
1da177e4 LT |
1917 | |
1918 | /* requested length too big for entire address space */ | |
2afc745f | 1919 | if (len > TASK_SIZE - mmap_min_addr) |
1da177e4 LT |
1920 | return -ENOMEM; |
1921 | ||
06abdfb4 BH |
1922 | if (flags & MAP_FIXED) |
1923 | return addr; | |
1924 | ||
1da177e4 LT |
1925 | /* requesting a specific address */ |
1926 | if (addr) { | |
1927 | addr = PAGE_ALIGN(addr); | |
1928 | vma = find_vma(mm, addr); | |
2afc745f | 1929 | if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && |
1da177e4 LT |
1930 | (!vma || addr + len <= vma->vm_start)) |
1931 | return addr; | |
1932 | } | |
1933 | ||
db4fbfb9 ML |
1934 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
1935 | info.length = len; | |
2afc745f | 1936 | info.low_limit = max(PAGE_SIZE, mmap_min_addr); |
db4fbfb9 ML |
1937 | info.high_limit = mm->mmap_base; |
1938 | info.align_mask = 0; | |
1939 | addr = vm_unmapped_area(&info); | |
b716ad95 | 1940 | |
1da177e4 LT |
1941 | /* |
1942 | * A failed mmap() very likely causes application failure, | |
1943 | * so fall back to the bottom-up function here. This scenario | |
1944 | * can happen with large stack limits and large mmap() | |
1945 | * allocations. | |
1946 | */ | |
db4fbfb9 ML |
1947 | if (addr & ~PAGE_MASK) { |
1948 | VM_BUG_ON(addr != -ENOMEM); | |
1949 | info.flags = 0; | |
1950 | info.low_limit = TASK_UNMAPPED_BASE; | |
1951 | info.high_limit = TASK_SIZE; | |
1952 | addr = vm_unmapped_area(&info); | |
1953 | } | |
1da177e4 LT |
1954 | |
1955 | return addr; | |
1956 | } | |
1957 | #endif | |
1958 | ||
1da177e4 LT |
1959 | unsigned long |
1960 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1961 | unsigned long pgoff, unsigned long flags) | |
1962 | { | |
06abdfb4 BH |
1963 | unsigned long (*get_area)(struct file *, unsigned long, |
1964 | unsigned long, unsigned long, unsigned long); | |
1965 | ||
9206de95 AV |
1966 | unsigned long error = arch_mmap_check(addr, len, flags); |
1967 | if (error) | |
1968 | return error; | |
1969 | ||
1970 | /* Careful about overflows.. */ | |
1971 | if (len > TASK_SIZE) | |
1972 | return -ENOMEM; | |
1973 | ||
06abdfb4 | 1974 | get_area = current->mm->get_unmapped_area; |
72c2d531 | 1975 | if (file && file->f_op->get_unmapped_area) |
06abdfb4 BH |
1976 | get_area = file->f_op->get_unmapped_area; |
1977 | addr = get_area(file, addr, len, pgoff, flags); | |
1978 | if (IS_ERR_VALUE(addr)) | |
1979 | return addr; | |
1da177e4 | 1980 | |
07ab67c8 LT |
1981 | if (addr > TASK_SIZE - len) |
1982 | return -ENOMEM; | |
1983 | if (addr & ~PAGE_MASK) | |
1984 | return -EINVAL; | |
06abdfb4 | 1985 | |
9ac4ed4b AV |
1986 | addr = arch_rebalance_pgtables(addr, len); |
1987 | error = security_mmap_addr(addr); | |
1988 | return error ? error : addr; | |
1da177e4 LT |
1989 | } |
1990 | ||
1991 | EXPORT_SYMBOL(get_unmapped_area); | |
1992 | ||
1993 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1994 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 | 1995 | { |
615d6e87 DB |
1996 | struct rb_node *rb_node; |
1997 | struct vm_area_struct *vma; | |
1da177e4 | 1998 | |
841e31e5 | 1999 | /* Check the cache first. */ |
615d6e87 DB |
2000 | vma = vmacache_find(mm, addr); |
2001 | if (likely(vma)) | |
2002 | return vma; | |
841e31e5 | 2003 | |
615d6e87 DB |
2004 | rb_node = mm->mm_rb.rb_node; |
2005 | vma = NULL; | |
841e31e5 | 2006 | |
615d6e87 DB |
2007 | while (rb_node) { |
2008 | struct vm_area_struct *tmp; | |
2009 | ||
2010 | tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
2011 | ||
2012 | if (tmp->vm_end > addr) { | |
2013 | vma = tmp; | |
2014 | if (tmp->vm_start <= addr) | |
2015 | break; | |
2016 | rb_node = rb_node->rb_left; | |
2017 | } else | |
2018 | rb_node = rb_node->rb_right; | |
1da177e4 | 2019 | } |
615d6e87 DB |
2020 | |
2021 | if (vma) | |
2022 | vmacache_update(addr, vma); | |
1da177e4 LT |
2023 | return vma; |
2024 | } | |
2025 | ||
2026 | EXPORT_SYMBOL(find_vma); | |
2027 | ||
6bd4837d KM |
2028 | /* |
2029 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 2030 | */ |
1da177e4 LT |
2031 | struct vm_area_struct * |
2032 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
2033 | struct vm_area_struct **pprev) | |
2034 | { | |
6bd4837d | 2035 | struct vm_area_struct *vma; |
1da177e4 | 2036 | |
6bd4837d | 2037 | vma = find_vma(mm, addr); |
83cd904d MP |
2038 | if (vma) { |
2039 | *pprev = vma->vm_prev; | |
2040 | } else { | |
2041 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
2042 | *pprev = NULL; | |
2043 | while (rb_node) { | |
2044 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
2045 | rb_node = rb_node->rb_right; | |
2046 | } | |
2047 | } | |
6bd4837d | 2048 | return vma; |
1da177e4 LT |
2049 | } |
2050 | ||
2051 | /* | |
2052 | * Verify that the stack growth is acceptable and | |
2053 | * update accounting. This is shared with both the | |
2054 | * grow-up and grow-down cases. | |
2055 | */ | |
48aae425 | 2056 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
2057 | { |
2058 | struct mm_struct *mm = vma->vm_mm; | |
2059 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 2060 | unsigned long new_start; |
1da177e4 LT |
2061 | |
2062 | /* address space limit tests */ | |
119f657c | 2063 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
2064 | return -ENOMEM; |
2065 | ||
2066 | /* Stack limit test */ | |
59e99e5b | 2067 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
1da177e4 LT |
2068 | return -ENOMEM; |
2069 | ||
2070 | /* mlock limit tests */ | |
2071 | if (vma->vm_flags & VM_LOCKED) { | |
2072 | unsigned long locked; | |
2073 | unsigned long limit; | |
2074 | locked = mm->locked_vm + grow; | |
59e99e5b JS |
2075 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
2076 | limit >>= PAGE_SHIFT; | |
1da177e4 LT |
2077 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
2078 | return -ENOMEM; | |
2079 | } | |
2080 | ||
0d59a01b AL |
2081 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
2082 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
2083 | vma->vm_end - size; | |
2084 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
2085 | return -EFAULT; | |
2086 | ||
1da177e4 LT |
2087 | /* |
2088 | * Overcommit.. This must be the final test, as it will | |
2089 | * update security statistics. | |
2090 | */ | |
05fa199d | 2091 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
2092 | return -ENOMEM; |
2093 | ||
2094 | /* Ok, everything looks good - let it rip */ | |
1da177e4 LT |
2095 | if (vma->vm_flags & VM_LOCKED) |
2096 | mm->locked_vm += grow; | |
ab50b8ed | 2097 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
2098 | return 0; |
2099 | } | |
2100 | ||
46dea3d0 | 2101 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 2102 | /* |
46dea3d0 HD |
2103 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
2104 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 2105 | */ |
46dea3d0 | 2106 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 LT |
2107 | { |
2108 | int error; | |
2109 | ||
2110 | if (!(vma->vm_flags & VM_GROWSUP)) | |
2111 | return -EFAULT; | |
2112 | ||
2113 | /* | |
2114 | * We must make sure the anon_vma is allocated | |
2115 | * so that the anon_vma locking is not a noop. | |
2116 | */ | |
2117 | if (unlikely(anon_vma_prepare(vma))) | |
2118 | return -ENOMEM; | |
bb4a340e | 2119 | vma_lock_anon_vma(vma); |
1da177e4 LT |
2120 | |
2121 | /* | |
2122 | * vma->vm_start/vm_end cannot change under us because the caller | |
2123 | * is required to hold the mmap_sem in read mode. We need the | |
2124 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 2125 | * Also guard against wrapping around to address 0. |
1da177e4 | 2126 | */ |
06b32f3a HD |
2127 | if (address < PAGE_ALIGN(address+4)) |
2128 | address = PAGE_ALIGN(address+4); | |
2129 | else { | |
bb4a340e | 2130 | vma_unlock_anon_vma(vma); |
06b32f3a HD |
2131 | return -ENOMEM; |
2132 | } | |
1da177e4 LT |
2133 | error = 0; |
2134 | ||
2135 | /* Somebody else might have raced and expanded it already */ | |
2136 | if (address > vma->vm_end) { | |
2137 | unsigned long size, grow; | |
2138 | ||
2139 | size = address - vma->vm_start; | |
2140 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
2141 | ||
42c36f63 HD |
2142 | error = -ENOMEM; |
2143 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
2144 | error = acct_stack_growth(vma, size, grow); | |
2145 | if (!error) { | |
4128997b ML |
2146 | /* |
2147 | * vma_gap_update() doesn't support concurrent | |
2148 | * updates, but we only hold a shared mmap_sem | |
2149 | * lock here, so we need to protect against | |
2150 | * concurrent vma expansions. | |
2151 | * vma_lock_anon_vma() doesn't help here, as | |
2152 | * we don't guarantee that all growable vmas | |
2153 | * in a mm share the same root anon vma. | |
2154 | * So, we reuse mm->page_table_lock to guard | |
2155 | * against concurrent vma expansions. | |
2156 | */ | |
2157 | spin_lock(&vma->vm_mm->page_table_lock); | |
bf181b9f | 2158 | anon_vma_interval_tree_pre_update_vma(vma); |
42c36f63 | 2159 | vma->vm_end = address; |
bf181b9f | 2160 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 ML |
2161 | if (vma->vm_next) |
2162 | vma_gap_update(vma->vm_next); | |
2163 | else | |
2164 | vma->vm_mm->highest_vm_end = address; | |
4128997b ML |
2165 | spin_unlock(&vma->vm_mm->page_table_lock); |
2166 | ||
42c36f63 HD |
2167 | perf_event_mmap(vma); |
2168 | } | |
3af9e859 | 2169 | } |
1da177e4 | 2170 | } |
bb4a340e | 2171 | vma_unlock_anon_vma(vma); |
b15d00b6 | 2172 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 2173 | validate_mm(vma->vm_mm); |
1da177e4 LT |
2174 | return error; |
2175 | } | |
46dea3d0 HD |
2176 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
2177 | ||
1da177e4 LT |
2178 | /* |
2179 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
2180 | */ | |
d05f3169 | 2181 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 2182 | unsigned long address) |
1da177e4 LT |
2183 | { |
2184 | int error; | |
2185 | ||
2186 | /* | |
2187 | * We must make sure the anon_vma is allocated | |
2188 | * so that the anon_vma locking is not a noop. | |
2189 | */ | |
2190 | if (unlikely(anon_vma_prepare(vma))) | |
2191 | return -ENOMEM; | |
8869477a EP |
2192 | |
2193 | address &= PAGE_MASK; | |
e5467859 | 2194 | error = security_mmap_addr(address); |
8869477a EP |
2195 | if (error) |
2196 | return error; | |
2197 | ||
bb4a340e | 2198 | vma_lock_anon_vma(vma); |
1da177e4 LT |
2199 | |
2200 | /* | |
2201 | * vma->vm_start/vm_end cannot change under us because the caller | |
2202 | * is required to hold the mmap_sem in read mode. We need the | |
2203 | * anon_vma lock to serialize against concurrent expand_stacks. | |
2204 | */ | |
1da177e4 LT |
2205 | |
2206 | /* Somebody else might have raced and expanded it already */ | |
2207 | if (address < vma->vm_start) { | |
2208 | unsigned long size, grow; | |
2209 | ||
2210 | size = vma->vm_end - address; | |
2211 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
2212 | ||
a626ca6a LT |
2213 | error = -ENOMEM; |
2214 | if (grow <= vma->vm_pgoff) { | |
2215 | error = acct_stack_growth(vma, size, grow); | |
2216 | if (!error) { | |
4128997b ML |
2217 | /* |
2218 | * vma_gap_update() doesn't support concurrent | |
2219 | * updates, but we only hold a shared mmap_sem | |
2220 | * lock here, so we need to protect against | |
2221 | * concurrent vma expansions. | |
2222 | * vma_lock_anon_vma() doesn't help here, as | |
2223 | * we don't guarantee that all growable vmas | |
2224 | * in a mm share the same root anon vma. | |
2225 | * So, we reuse mm->page_table_lock to guard | |
2226 | * against concurrent vma expansions. | |
2227 | */ | |
2228 | spin_lock(&vma->vm_mm->page_table_lock); | |
bf181b9f | 2229 | anon_vma_interval_tree_pre_update_vma(vma); |
a626ca6a LT |
2230 | vma->vm_start = address; |
2231 | vma->vm_pgoff -= grow; | |
bf181b9f | 2232 | anon_vma_interval_tree_post_update_vma(vma); |
d3737187 | 2233 | vma_gap_update(vma); |
4128997b ML |
2234 | spin_unlock(&vma->vm_mm->page_table_lock); |
2235 | ||
a626ca6a LT |
2236 | perf_event_mmap(vma); |
2237 | } | |
1da177e4 LT |
2238 | } |
2239 | } | |
bb4a340e | 2240 | vma_unlock_anon_vma(vma); |
b15d00b6 | 2241 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 2242 | validate_mm(vma->vm_mm); |
1da177e4 LT |
2243 | return error; |
2244 | } | |
2245 | ||
09884964 LT |
2246 | /* |
2247 | * Note how expand_stack() refuses to expand the stack all the way to | |
2248 | * abut the next virtual mapping, *unless* that mapping itself is also | |
2249 | * a stack mapping. We want to leave room for a guard page, after all | |
2250 | * (the guard page itself is not added here, that is done by the | |
2251 | * actual page faulting logic) | |
2252 | * | |
2253 | * This matches the behavior of the guard page logic (see mm/memory.c: | |
2254 | * check_stack_guard_page()), which only allows the guard page to be | |
2255 | * removed under these circumstances. | |
2256 | */ | |
b6a2fea3 OW |
2257 | #ifdef CONFIG_STACK_GROWSUP |
2258 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2259 | { | |
09884964 LT |
2260 | struct vm_area_struct *next; |
2261 | ||
2262 | address &= PAGE_MASK; | |
2263 | next = vma->vm_next; | |
2264 | if (next && next->vm_start == address + PAGE_SIZE) { | |
2265 | if (!(next->vm_flags & VM_GROWSUP)) | |
2266 | return -ENOMEM; | |
2267 | } | |
b6a2fea3 OW |
2268 | return expand_upwards(vma, address); |
2269 | } | |
2270 | ||
2271 | struct vm_area_struct * | |
2272 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
2273 | { | |
2274 | struct vm_area_struct *vma, *prev; | |
2275 | ||
2276 | addr &= PAGE_MASK; | |
2277 | vma = find_vma_prev(mm, addr, &prev); | |
2278 | if (vma && (vma->vm_start <= addr)) | |
2279 | return vma; | |
1c127185 | 2280 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 2281 | return NULL; |
cea10a19 ML |
2282 | if (prev->vm_flags & VM_LOCKED) |
2283 | __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL); | |
b6a2fea3 OW |
2284 | return prev; |
2285 | } | |
2286 | #else | |
2287 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
2288 | { | |
09884964 LT |
2289 | struct vm_area_struct *prev; |
2290 | ||
2291 | address &= PAGE_MASK; | |
2292 | prev = vma->vm_prev; | |
2293 | if (prev && prev->vm_end == address) { | |
2294 | if (!(prev->vm_flags & VM_GROWSDOWN)) | |
2295 | return -ENOMEM; | |
2296 | } | |
b6a2fea3 OW |
2297 | return expand_downwards(vma, address); |
2298 | } | |
2299 | ||
1da177e4 LT |
2300 | struct vm_area_struct * |
2301 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
2302 | { | |
2303 | struct vm_area_struct * vma; | |
2304 | unsigned long start; | |
2305 | ||
2306 | addr &= PAGE_MASK; | |
2307 | vma = find_vma(mm,addr); | |
2308 | if (!vma) | |
2309 | return NULL; | |
2310 | if (vma->vm_start <= addr) | |
2311 | return vma; | |
2312 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
2313 | return NULL; | |
2314 | start = vma->vm_start; | |
2315 | if (expand_stack(vma, addr)) | |
2316 | return NULL; | |
cea10a19 ML |
2317 | if (vma->vm_flags & VM_LOCKED) |
2318 | __mlock_vma_pages_range(vma, addr, start, NULL); | |
1da177e4 LT |
2319 | return vma; |
2320 | } | |
2321 | #endif | |
2322 | ||
1da177e4 | 2323 | /* |
2c0b3814 | 2324 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 2325 | * so release them, and do the vma updates. |
2c0b3814 HD |
2326 | * |
2327 | * Called with the mm semaphore held. | |
1da177e4 | 2328 | */ |
2c0b3814 | 2329 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2330 | { |
4f74d2c8 LT |
2331 | unsigned long nr_accounted = 0; |
2332 | ||
365e9c87 HD |
2333 | /* Update high watermark before we lower total_vm */ |
2334 | update_hiwater_vm(mm); | |
1da177e4 | 2335 | do { |
2c0b3814 HD |
2336 | long nrpages = vma_pages(vma); |
2337 | ||
4f74d2c8 LT |
2338 | if (vma->vm_flags & VM_ACCOUNT) |
2339 | nr_accounted += nrpages; | |
2c0b3814 | 2340 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 2341 | vma = remove_vma(vma); |
146425a3 | 2342 | } while (vma); |
4f74d2c8 | 2343 | vm_unacct_memory(nr_accounted); |
1da177e4 LT |
2344 | validate_mm(mm); |
2345 | } | |
2346 | ||
2347 | /* | |
2348 | * Get rid of page table information in the indicated region. | |
2349 | * | |
f10df686 | 2350 | * Called with the mm semaphore held. |
1da177e4 LT |
2351 | */ |
2352 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
2353 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
2354 | unsigned long start, unsigned long end) | |
1da177e4 | 2355 | { |
e0da382c | 2356 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
d16dfc55 | 2357 | struct mmu_gather tlb; |
1da177e4 LT |
2358 | |
2359 | lru_add_drain(); | |
2b047252 | 2360 | tlb_gather_mmu(&tlb, mm, start, end); |
365e9c87 | 2361 | update_hiwater_rss(mm); |
4f74d2c8 | 2362 | unmap_vmas(&tlb, vma, start, end); |
d16dfc55 | 2363 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
6ee8630e | 2364 | next ? next->vm_start : USER_PGTABLES_CEILING); |
d16dfc55 | 2365 | tlb_finish_mmu(&tlb, start, end); |
1da177e4 LT |
2366 | } |
2367 | ||
2368 | /* | |
2369 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
2370 | * vma list as we go.. | |
2371 | */ | |
2372 | static void | |
2373 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
2374 | struct vm_area_struct *prev, unsigned long end) | |
2375 | { | |
2376 | struct vm_area_struct **insertion_point; | |
2377 | struct vm_area_struct *tail_vma = NULL; | |
2378 | ||
2379 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 2380 | vma->vm_prev = NULL; |
1da177e4 | 2381 | do { |
d3737187 | 2382 | vma_rb_erase(vma, &mm->mm_rb); |
1da177e4 LT |
2383 | mm->map_count--; |
2384 | tail_vma = vma; | |
2385 | vma = vma->vm_next; | |
2386 | } while (vma && vma->vm_start < end); | |
2387 | *insertion_point = vma; | |
d3737187 | 2388 | if (vma) { |
297c5eee | 2389 | vma->vm_prev = prev; |
d3737187 ML |
2390 | vma_gap_update(vma); |
2391 | } else | |
2392 | mm->highest_vm_end = prev ? prev->vm_end : 0; | |
1da177e4 | 2393 | tail_vma->vm_next = NULL; |
615d6e87 DB |
2394 | |
2395 | /* Kill the cache */ | |
2396 | vmacache_invalidate(mm); | |
1da177e4 LT |
2397 | } |
2398 | ||
2399 | /* | |
659ace58 KM |
2400 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
2401 | * munmap path where it doesn't make sense to fail. | |
1da177e4 | 2402 | */ |
659ace58 | 2403 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1da177e4 LT |
2404 | unsigned long addr, int new_below) |
2405 | { | |
1da177e4 | 2406 | struct vm_area_struct *new; |
5beb4930 | 2407 | int err = -ENOMEM; |
1da177e4 | 2408 | |
a5516438 AK |
2409 | if (is_vm_hugetlb_page(vma) && (addr & |
2410 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
2411 | return -EINVAL; |
2412 | ||
e94b1766 | 2413 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 2414 | if (!new) |
5beb4930 | 2415 | goto out_err; |
1da177e4 LT |
2416 | |
2417 | /* most fields are the same, copy all, and then fixup */ | |
2418 | *new = *vma; | |
2419 | ||
5beb4930 RR |
2420 | INIT_LIST_HEAD(&new->anon_vma_chain); |
2421 | ||
1da177e4 LT |
2422 | if (new_below) |
2423 | new->vm_end = addr; | |
2424 | else { | |
2425 | new->vm_start = addr; | |
2426 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
2427 | } | |
2428 | ||
ef0855d3 ON |
2429 | err = vma_dup_policy(vma, new); |
2430 | if (err) | |
5beb4930 | 2431 | goto out_free_vma; |
1da177e4 | 2432 | |
5beb4930 RR |
2433 | if (anon_vma_clone(new, vma)) |
2434 | goto out_free_mpol; | |
2435 | ||
e9714acf | 2436 | if (new->vm_file) |
1da177e4 LT |
2437 | get_file(new->vm_file); |
2438 | ||
2439 | if (new->vm_ops && new->vm_ops->open) | |
2440 | new->vm_ops->open(new); | |
2441 | ||
2442 | if (new_below) | |
5beb4930 | 2443 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
2444 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
2445 | else | |
5beb4930 | 2446 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 2447 | |
5beb4930 RR |
2448 | /* Success. */ |
2449 | if (!err) | |
2450 | return 0; | |
2451 | ||
2452 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
2453 | if (new->vm_ops && new->vm_ops->close) |
2454 | new->vm_ops->close(new); | |
e9714acf | 2455 | if (new->vm_file) |
5beb4930 | 2456 | fput(new->vm_file); |
2aeadc30 | 2457 | unlink_anon_vmas(new); |
5beb4930 | 2458 | out_free_mpol: |
ef0855d3 | 2459 | mpol_put(vma_policy(new)); |
5beb4930 RR |
2460 | out_free_vma: |
2461 | kmem_cache_free(vm_area_cachep, new); | |
2462 | out_err: | |
2463 | return err; | |
1da177e4 LT |
2464 | } |
2465 | ||
659ace58 KM |
2466 | /* |
2467 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2468 | * either for the first part or the tail. | |
2469 | */ | |
2470 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2471 | unsigned long addr, int new_below) | |
2472 | { | |
2473 | if (mm->map_count >= sysctl_max_map_count) | |
2474 | return -ENOMEM; | |
2475 | ||
2476 | return __split_vma(mm, vma, addr, new_below); | |
2477 | } | |
2478 | ||
1da177e4 LT |
2479 | /* Munmap is split into 2 main parts -- this part which finds |
2480 | * what needs doing, and the areas themselves, which do the | |
2481 | * work. This now handles partial unmappings. | |
2482 | * Jeremy Fitzhardinge <[email protected]> | |
2483 | */ | |
2484 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
2485 | { | |
2486 | unsigned long end; | |
146425a3 | 2487 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
2488 | |
2489 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
2490 | return -EINVAL; | |
2491 | ||
2492 | if ((len = PAGE_ALIGN(len)) == 0) | |
2493 | return -EINVAL; | |
2494 | ||
2495 | /* Find the first overlapping VMA */ | |
9be34c9d | 2496 | vma = find_vma(mm, start); |
146425a3 | 2497 | if (!vma) |
1da177e4 | 2498 | return 0; |
9be34c9d | 2499 | prev = vma->vm_prev; |
146425a3 | 2500 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2501 | |
2502 | /* if it doesn't overlap, we have nothing.. */ | |
2503 | end = start + len; | |
146425a3 | 2504 | if (vma->vm_start >= end) |
1da177e4 LT |
2505 | return 0; |
2506 | ||
2507 | /* | |
2508 | * If we need to split any vma, do it now to save pain later. | |
2509 | * | |
2510 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2511 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2512 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2513 | */ | |
146425a3 | 2514 | if (start > vma->vm_start) { |
659ace58 KM |
2515 | int error; |
2516 | ||
2517 | /* | |
2518 | * Make sure that map_count on return from munmap() will | |
2519 | * not exceed its limit; but let map_count go just above | |
2520 | * its limit temporarily, to help free resources as expected. | |
2521 | */ | |
2522 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2523 | return -ENOMEM; | |
2524 | ||
2525 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2526 | if (error) |
2527 | return error; | |
146425a3 | 2528 | prev = vma; |
1da177e4 LT |
2529 | } |
2530 | ||
2531 | /* Does it split the last one? */ | |
2532 | last = find_vma(mm, end); | |
2533 | if (last && end > last->vm_start) { | |
659ace58 | 2534 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2535 | if (error) |
2536 | return error; | |
2537 | } | |
146425a3 | 2538 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 2539 | |
ba470de4 RR |
2540 | /* |
2541 | * unlock any mlock()ed ranges before detaching vmas | |
2542 | */ | |
2543 | if (mm->locked_vm) { | |
2544 | struct vm_area_struct *tmp = vma; | |
2545 | while (tmp && tmp->vm_start < end) { | |
2546 | if (tmp->vm_flags & VM_LOCKED) { | |
2547 | mm->locked_vm -= vma_pages(tmp); | |
2548 | munlock_vma_pages_all(tmp); | |
2549 | } | |
2550 | tmp = tmp->vm_next; | |
2551 | } | |
2552 | } | |
2553 | ||
1da177e4 LT |
2554 | /* |
2555 | * Remove the vma's, and unmap the actual pages | |
2556 | */ | |
146425a3 HD |
2557 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2558 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
2559 | |
2560 | /* Fix up all other VM information */ | |
2c0b3814 | 2561 | remove_vma_list(mm, vma); |
1da177e4 LT |
2562 | |
2563 | return 0; | |
2564 | } | |
1da177e4 | 2565 | |
bfce281c | 2566 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2567 | { |
2568 | int ret; | |
bfce281c | 2569 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
2570 | |
2571 | down_write(&mm->mmap_sem); | |
a46ef99d | 2572 | ret = do_munmap(mm, start, len); |
1da177e4 LT |
2573 | up_write(&mm->mmap_sem); |
2574 | return ret; | |
2575 | } | |
a46ef99d LT |
2576 | EXPORT_SYMBOL(vm_munmap); |
2577 | ||
2578 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2579 | { | |
2580 | profile_munmap(addr); | |
bfce281c | 2581 | return vm_munmap(addr, len); |
a46ef99d | 2582 | } |
1da177e4 LT |
2583 | |
2584 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
2585 | { | |
a241ec65 | 2586 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2587 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2588 | WARN_ON(1); | |
2589 | up_read(&mm->mmap_sem); | |
2590 | } | |
2591 | #endif | |
2592 | } | |
2593 | ||
2594 | /* | |
2595 | * this is really a simplified "do_mmap". it only handles | |
2596 | * anonymous maps. eventually we may be able to do some | |
2597 | * brk-specific accounting here. | |
2598 | */ | |
e4eb1ff6 | 2599 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
1da177e4 LT |
2600 | { |
2601 | struct mm_struct * mm = current->mm; | |
2602 | struct vm_area_struct * vma, * prev; | |
2603 | unsigned long flags; | |
2604 | struct rb_node ** rb_link, * rb_parent; | |
2605 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 2606 | int error; |
1da177e4 LT |
2607 | |
2608 | len = PAGE_ALIGN(len); | |
2609 | if (!len) | |
2610 | return addr; | |
2611 | ||
3a459756 KK |
2612 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2613 | ||
2c6a1016 AV |
2614 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
2615 | if (error & ~PAGE_MASK) | |
3a459756 KK |
2616 | return error; |
2617 | ||
363ee17f DB |
2618 | error = mlock_future_check(mm, mm->def_flags, len); |
2619 | if (error) | |
2620 | return error; | |
1da177e4 LT |
2621 | |
2622 | /* | |
2623 | * mm->mmap_sem is required to protect against another thread | |
2624 | * changing the mappings in case we sleep. | |
2625 | */ | |
2626 | verify_mm_writelocked(mm); | |
2627 | ||
2628 | /* | |
2629 | * Clear old maps. this also does some error checking for us | |
2630 | */ | |
2631 | munmap_back: | |
6597d783 | 2632 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
2633 | if (do_munmap(mm, addr, len)) |
2634 | return -ENOMEM; | |
2635 | goto munmap_back; | |
2636 | } | |
2637 | ||
2638 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2639 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2640 | return -ENOMEM; |
2641 | ||
2642 | if (mm->map_count > sysctl_max_map_count) | |
2643 | return -ENOMEM; | |
2644 | ||
191c5424 | 2645 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2646 | return -ENOMEM; |
2647 | ||
1da177e4 | 2648 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2649 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2650 | NULL, NULL, pgoff, NULL); | |
2651 | if (vma) | |
1da177e4 LT |
2652 | goto out; |
2653 | ||
2654 | /* | |
2655 | * create a vma struct for an anonymous mapping | |
2656 | */ | |
c5e3b83e | 2657 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2658 | if (!vma) { |
2659 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2660 | return -ENOMEM; | |
2661 | } | |
1da177e4 | 2662 | |
5beb4930 | 2663 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2664 | vma->vm_mm = mm; |
2665 | vma->vm_start = addr; | |
2666 | vma->vm_end = addr + len; | |
2667 | vma->vm_pgoff = pgoff; | |
2668 | vma->vm_flags = flags; | |
3ed75eb8 | 2669 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2670 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2671 | out: | |
3af9e859 | 2672 | perf_event_mmap(vma); |
1da177e4 | 2673 | mm->total_vm += len >> PAGE_SHIFT; |
128557ff ML |
2674 | if (flags & VM_LOCKED) |
2675 | mm->locked_vm += (len >> PAGE_SHIFT); | |
d9104d1c | 2676 | vma->vm_flags |= VM_SOFTDIRTY; |
1da177e4 LT |
2677 | return addr; |
2678 | } | |
2679 | ||
e4eb1ff6 LT |
2680 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
2681 | { | |
2682 | struct mm_struct *mm = current->mm; | |
2683 | unsigned long ret; | |
128557ff | 2684 | bool populate; |
e4eb1ff6 LT |
2685 | |
2686 | down_write(&mm->mmap_sem); | |
2687 | ret = do_brk(addr, len); | |
128557ff | 2688 | populate = ((mm->def_flags & VM_LOCKED) != 0); |
e4eb1ff6 | 2689 | up_write(&mm->mmap_sem); |
128557ff ML |
2690 | if (populate) |
2691 | mm_populate(addr, len); | |
e4eb1ff6 LT |
2692 | return ret; |
2693 | } | |
2694 | EXPORT_SYMBOL(vm_brk); | |
1da177e4 LT |
2695 | |
2696 | /* Release all mmaps. */ | |
2697 | void exit_mmap(struct mm_struct *mm) | |
2698 | { | |
d16dfc55 | 2699 | struct mmu_gather tlb; |
ba470de4 | 2700 | struct vm_area_struct *vma; |
1da177e4 LT |
2701 | unsigned long nr_accounted = 0; |
2702 | ||
d6dd61c8 | 2703 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2704 | mmu_notifier_release(mm); |
d6dd61c8 | 2705 | |
ba470de4 RR |
2706 | if (mm->locked_vm) { |
2707 | vma = mm->mmap; | |
2708 | while (vma) { | |
2709 | if (vma->vm_flags & VM_LOCKED) | |
2710 | munlock_vma_pages_all(vma); | |
2711 | vma = vma->vm_next; | |
2712 | } | |
2713 | } | |
9480c53e JF |
2714 | |
2715 | arch_exit_mmap(mm); | |
2716 | ||
ba470de4 | 2717 | vma = mm->mmap; |
9480c53e JF |
2718 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2719 | return; | |
2720 | ||
1da177e4 | 2721 | lru_add_drain(); |
1da177e4 | 2722 | flush_cache_mm(mm); |
2b047252 | 2723 | tlb_gather_mmu(&tlb, mm, 0, -1); |
901608d9 | 2724 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2725 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
4f74d2c8 | 2726 | unmap_vmas(&tlb, vma, 0, -1); |
9ba69294 | 2727 | |
6ee8630e | 2728 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); |
853f5e26 | 2729 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 2730 | |
1da177e4 | 2731 | /* |
8f4f8c16 HD |
2732 | * Walk the list again, actually closing and freeing it, |
2733 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2734 | */ |
4f74d2c8 LT |
2735 | while (vma) { |
2736 | if (vma->vm_flags & VM_ACCOUNT) | |
2737 | nr_accounted += vma_pages(vma); | |
a8fb5618 | 2738 | vma = remove_vma(vma); |
4f74d2c8 LT |
2739 | } |
2740 | vm_unacct_memory(nr_accounted); | |
e0da382c | 2741 | |
e1f56c89 KS |
2742 | WARN_ON(atomic_long_read(&mm->nr_ptes) > |
2743 | (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); | |
1da177e4 LT |
2744 | } |
2745 | ||
2746 | /* Insert vm structure into process list sorted by address | |
2747 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
3d48ae45 | 2748 | * then i_mmap_mutex is taken here. |
1da177e4 | 2749 | */ |
6597d783 | 2750 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2751 | { |
6597d783 HD |
2752 | struct vm_area_struct *prev; |
2753 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
2754 | |
2755 | /* | |
2756 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2757 | * until its first write fault, when page's anon_vma and index | |
2758 | * are set. But now set the vm_pgoff it will almost certainly | |
2759 | * end up with (unless mremap moves it elsewhere before that | |
2760 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2761 | * | |
2762 | * By setting it to reflect the virtual start address of the | |
2763 | * vma, merges and splits can happen in a seamless way, just | |
2764 | * using the existing file pgoff checks and manipulations. | |
2765 | * Similarly in do_mmap_pgoff and in do_brk. | |
2766 | */ | |
2767 | if (!vma->vm_file) { | |
2768 | BUG_ON(vma->anon_vma); | |
2769 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2770 | } | |
6597d783 HD |
2771 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
2772 | &prev, &rb_link, &rb_parent)) | |
1da177e4 | 2773 | return -ENOMEM; |
2fd4ef85 | 2774 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2775 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2776 | return -ENOMEM; |
2b144498 | 2777 | |
1da177e4 LT |
2778 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2779 | return 0; | |
2780 | } | |
2781 | ||
2782 | /* | |
2783 | * Copy the vma structure to a new location in the same mm, | |
2784 | * prior to moving page table entries, to effect an mremap move. | |
2785 | */ | |
2786 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
38a76013 ML |
2787 | unsigned long addr, unsigned long len, pgoff_t pgoff, |
2788 | bool *need_rmap_locks) | |
1da177e4 LT |
2789 | { |
2790 | struct vm_area_struct *vma = *vmap; | |
2791 | unsigned long vma_start = vma->vm_start; | |
2792 | struct mm_struct *mm = vma->vm_mm; | |
2793 | struct vm_area_struct *new_vma, *prev; | |
2794 | struct rb_node **rb_link, *rb_parent; | |
948f017b | 2795 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
2796 | |
2797 | /* | |
2798 | * If anonymous vma has not yet been faulted, update new pgoff | |
2799 | * to match new location, to increase its chance of merging. | |
2800 | */ | |
948f017b | 2801 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
1da177e4 | 2802 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
2803 | faulted_in_anon_vma = false; |
2804 | } | |
1da177e4 | 2805 | |
6597d783 HD |
2806 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
2807 | return NULL; /* should never get here */ | |
1da177e4 LT |
2808 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
2809 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2810 | if (new_vma) { | |
2811 | /* | |
2812 | * Source vma may have been merged into new_vma | |
2813 | */ | |
948f017b AA |
2814 | if (unlikely(vma_start >= new_vma->vm_start && |
2815 | vma_start < new_vma->vm_end)) { | |
2816 | /* | |
2817 | * The only way we can get a vma_merge with | |
2818 | * self during an mremap is if the vma hasn't | |
2819 | * been faulted in yet and we were allowed to | |
2820 | * reset the dst vma->vm_pgoff to the | |
2821 | * destination address of the mremap to allow | |
2822 | * the merge to happen. mremap must change the | |
2823 | * vm_pgoff linearity between src and dst vmas | |
2824 | * (in turn preventing a vma_merge) to be | |
2825 | * safe. It is only safe to keep the vm_pgoff | |
2826 | * linear if there are no pages mapped yet. | |
2827 | */ | |
2828 | VM_BUG_ON(faulted_in_anon_vma); | |
38a76013 | 2829 | *vmap = vma = new_vma; |
108d6642 | 2830 | } |
38a76013 | 2831 | *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); |
1da177e4 | 2832 | } else { |
e94b1766 | 2833 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2834 | if (new_vma) { |
2835 | *new_vma = *vma; | |
523d4e20 ML |
2836 | new_vma->vm_start = addr; |
2837 | new_vma->vm_end = addr + len; | |
2838 | new_vma->vm_pgoff = pgoff; | |
ef0855d3 | 2839 | if (vma_dup_policy(vma, new_vma)) |
5beb4930 RR |
2840 | goto out_free_vma; |
2841 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); | |
2842 | if (anon_vma_clone(new_vma, vma)) | |
2843 | goto out_free_mempol; | |
e9714acf | 2844 | if (new_vma->vm_file) |
1da177e4 LT |
2845 | get_file(new_vma->vm_file); |
2846 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
2847 | new_vma->vm_ops->open(new_vma); | |
2848 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
38a76013 | 2849 | *need_rmap_locks = false; |
1da177e4 LT |
2850 | } |
2851 | } | |
2852 | return new_vma; | |
5beb4930 RR |
2853 | |
2854 | out_free_mempol: | |
ef0855d3 | 2855 | mpol_put(vma_policy(new_vma)); |
5beb4930 RR |
2856 | out_free_vma: |
2857 | kmem_cache_free(vm_area_cachep, new_vma); | |
2858 | return NULL; | |
1da177e4 | 2859 | } |
119f657c | 2860 | |
2861 | /* | |
2862 | * Return true if the calling process may expand its vm space by the passed | |
2863 | * number of pages | |
2864 | */ | |
2865 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2866 | { | |
2867 | unsigned long cur = mm->total_vm; /* pages */ | |
2868 | unsigned long lim; | |
2869 | ||
59e99e5b | 2870 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
119f657c | 2871 | |
2872 | if (cur + npages > lim) | |
2873 | return 0; | |
2874 | return 1; | |
2875 | } | |
fa5dc22f | 2876 | |
a62c34bd AL |
2877 | static int special_mapping_fault(struct vm_area_struct *vma, |
2878 | struct vm_fault *vmf); | |
2879 | ||
2880 | /* | |
2881 | * Having a close hook prevents vma merging regardless of flags. | |
2882 | */ | |
2883 | static void special_mapping_close(struct vm_area_struct *vma) | |
2884 | { | |
2885 | } | |
2886 | ||
2887 | static const char *special_mapping_name(struct vm_area_struct *vma) | |
2888 | { | |
2889 | return ((struct vm_special_mapping *)vma->vm_private_data)->name; | |
2890 | } | |
2891 | ||
2892 | static const struct vm_operations_struct special_mapping_vmops = { | |
2893 | .close = special_mapping_close, | |
2894 | .fault = special_mapping_fault, | |
2895 | .name = special_mapping_name, | |
2896 | }; | |
2897 | ||
2898 | static const struct vm_operations_struct legacy_special_mapping_vmops = { | |
2899 | .close = special_mapping_close, | |
2900 | .fault = special_mapping_fault, | |
2901 | }; | |
fa5dc22f | 2902 | |
b1d0e4f5 NP |
2903 | static int special_mapping_fault(struct vm_area_struct *vma, |
2904 | struct vm_fault *vmf) | |
fa5dc22f | 2905 | { |
b1d0e4f5 | 2906 | pgoff_t pgoff; |
fa5dc22f RM |
2907 | struct page **pages; |
2908 | ||
b1d0e4f5 NP |
2909 | /* |
2910 | * special mappings have no vm_file, and in that case, the mm | |
2911 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2912 | * We are allowed to do this because we are the mm; do not copy | |
2913 | * this code into drivers! | |
2914 | */ | |
2915 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2916 | |
a62c34bd AL |
2917 | if (vma->vm_ops == &legacy_special_mapping_vmops) |
2918 | pages = vma->vm_private_data; | |
2919 | else | |
2920 | pages = ((struct vm_special_mapping *)vma->vm_private_data)-> | |
2921 | pages; | |
2922 | ||
2923 | for (; pgoff && *pages; ++pages) | |
b1d0e4f5 | 2924 | pgoff--; |
fa5dc22f RM |
2925 | |
2926 | if (*pages) { | |
2927 | struct page *page = *pages; | |
2928 | get_page(page); | |
b1d0e4f5 NP |
2929 | vmf->page = page; |
2930 | return 0; | |
fa5dc22f RM |
2931 | } |
2932 | ||
b1d0e4f5 | 2933 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2934 | } |
2935 | ||
a62c34bd AL |
2936 | static struct vm_area_struct *__install_special_mapping( |
2937 | struct mm_struct *mm, | |
2938 | unsigned long addr, unsigned long len, | |
2939 | unsigned long vm_flags, const struct vm_operations_struct *ops, | |
2940 | void *priv) | |
fa5dc22f | 2941 | { |
462e635e | 2942 | int ret; |
fa5dc22f RM |
2943 | struct vm_area_struct *vma; |
2944 | ||
2945 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2946 | if (unlikely(vma == NULL)) | |
3935ed6a | 2947 | return ERR_PTR(-ENOMEM); |
fa5dc22f | 2948 | |
5beb4930 | 2949 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
2950 | vma->vm_mm = mm; |
2951 | vma->vm_start = addr; | |
2952 | vma->vm_end = addr + len; | |
2953 | ||
d9104d1c | 2954 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; |
3ed75eb8 | 2955 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f | 2956 | |
a62c34bd AL |
2957 | vma->vm_ops = ops; |
2958 | vma->vm_private_data = priv; | |
fa5dc22f | 2959 | |
462e635e TO |
2960 | ret = insert_vm_struct(mm, vma); |
2961 | if (ret) | |
2962 | goto out; | |
fa5dc22f RM |
2963 | |
2964 | mm->total_vm += len >> PAGE_SHIFT; | |
2965 | ||
cdd6c482 | 2966 | perf_event_mmap(vma); |
089dd79d | 2967 | |
3935ed6a | 2968 | return vma; |
462e635e TO |
2969 | |
2970 | out: | |
2971 | kmem_cache_free(vm_area_cachep, vma); | |
3935ed6a SS |
2972 | return ERR_PTR(ret); |
2973 | } | |
2974 | ||
a62c34bd AL |
2975 | /* |
2976 | * Called with mm->mmap_sem held for writing. | |
2977 | * Insert a new vma covering the given region, with the given flags. | |
2978 | * Its pages are supplied by the given array of struct page *. | |
2979 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2980 | * The region past the last page supplied will always produce SIGBUS. | |
2981 | * The array pointer and the pages it points to are assumed to stay alive | |
2982 | * for as long as this mapping might exist. | |
2983 | */ | |
2984 | struct vm_area_struct *_install_special_mapping( | |
2985 | struct mm_struct *mm, | |
2986 | unsigned long addr, unsigned long len, | |
2987 | unsigned long vm_flags, const struct vm_special_mapping *spec) | |
2988 | { | |
2989 | return __install_special_mapping(mm, addr, len, vm_flags, | |
2990 | &special_mapping_vmops, (void *)spec); | |
2991 | } | |
2992 | ||
3935ed6a SS |
2993 | int install_special_mapping(struct mm_struct *mm, |
2994 | unsigned long addr, unsigned long len, | |
2995 | unsigned long vm_flags, struct page **pages) | |
2996 | { | |
a62c34bd AL |
2997 | struct vm_area_struct *vma = __install_special_mapping( |
2998 | mm, addr, len, vm_flags, &legacy_special_mapping_vmops, | |
2999 | (void *)pages); | |
3935ed6a | 3000 | |
14bd5b45 | 3001 | return PTR_ERR_OR_ZERO(vma); |
fa5dc22f | 3002 | } |
7906d00c AA |
3003 | |
3004 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
3005 | ||
454ed842 | 3006 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 3007 | { |
bf181b9f | 3008 | if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
3009 | /* |
3010 | * The LSB of head.next can't change from under us | |
3011 | * because we hold the mm_all_locks_mutex. | |
3012 | */ | |
572043c9 | 3013 | down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); |
7906d00c AA |
3014 | /* |
3015 | * We can safely modify head.next after taking the | |
5a505085 | 3016 | * anon_vma->root->rwsem. If some other vma in this mm shares |
7906d00c AA |
3017 | * the same anon_vma we won't take it again. |
3018 | * | |
3019 | * No need of atomic instructions here, head.next | |
3020 | * can't change from under us thanks to the | |
5a505085 | 3021 | * anon_vma->root->rwsem. |
7906d00c AA |
3022 | */ |
3023 | if (__test_and_set_bit(0, (unsigned long *) | |
bf181b9f | 3024 | &anon_vma->root->rb_root.rb_node)) |
7906d00c AA |
3025 | BUG(); |
3026 | } | |
3027 | } | |
3028 | ||
454ed842 | 3029 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
3030 | { |
3031 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
3032 | /* | |
3033 | * AS_MM_ALL_LOCKS can't change from under us because | |
3034 | * we hold the mm_all_locks_mutex. | |
3035 | * | |
3036 | * Operations on ->flags have to be atomic because | |
3037 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
3038 | * mm_all_locks_mutex, there may be other cpus | |
3039 | * changing other bitflags in parallel to us. | |
3040 | */ | |
3041 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
3042 | BUG(); | |
3d48ae45 | 3043 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
7906d00c AA |
3044 | } |
3045 | } | |
3046 | ||
3047 | /* | |
3048 | * This operation locks against the VM for all pte/vma/mm related | |
3049 | * operations that could ever happen on a certain mm. This includes | |
3050 | * vmtruncate, try_to_unmap, and all page faults. | |
3051 | * | |
3052 | * The caller must take the mmap_sem in write mode before calling | |
3053 | * mm_take_all_locks(). The caller isn't allowed to release the | |
3054 | * mmap_sem until mm_drop_all_locks() returns. | |
3055 | * | |
3056 | * mmap_sem in write mode is required in order to block all operations | |
3057 | * that could modify pagetables and free pages without need of | |
3058 | * altering the vma layout (for example populate_range() with | |
3059 | * nonlinear vmas). It's also needed in write mode to avoid new | |
3060 | * anon_vmas to be associated with existing vmas. | |
3061 | * | |
3062 | * A single task can't take more than one mm_take_all_locks() in a row | |
3063 | * or it would deadlock. | |
3064 | * | |
bf181b9f | 3065 | * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in |
7906d00c AA |
3066 | * mapping->flags avoid to take the same lock twice, if more than one |
3067 | * vma in this mm is backed by the same anon_vma or address_space. | |
3068 | * | |
3069 | * We can take all the locks in random order because the VM code | |
631b0cfd | 3070 | * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never |
7906d00c AA |
3071 | * takes more than one of them in a row. Secondly we're protected |
3072 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
3073 | * | |
3074 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
3075 | * that may have to take thousand of locks. | |
3076 | * | |
3077 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
3078 | */ | |
3079 | int mm_take_all_locks(struct mm_struct *mm) | |
3080 | { | |
3081 | struct vm_area_struct *vma; | |
5beb4930 | 3082 | struct anon_vma_chain *avc; |
7906d00c AA |
3083 | |
3084 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3085 | ||
3086 | mutex_lock(&mm_all_locks_mutex); | |
3087 | ||
3088 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3089 | if (signal_pending(current)) | |
3090 | goto out_unlock; | |
7906d00c | 3091 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 3092 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 3093 | } |
7cd5a02f PZ |
3094 | |
3095 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3096 | if (signal_pending(current)) | |
3097 | goto out_unlock; | |
3098 | if (vma->anon_vma) | |
5beb4930 RR |
3099 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3100 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 3101 | } |
7cd5a02f | 3102 | |
584cff54 | 3103 | return 0; |
7906d00c AA |
3104 | |
3105 | out_unlock: | |
584cff54 KC |
3106 | mm_drop_all_locks(mm); |
3107 | return -EINTR; | |
7906d00c AA |
3108 | } |
3109 | ||
3110 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
3111 | { | |
bf181b9f | 3112 | if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
3113 | /* |
3114 | * The LSB of head.next can't change to 0 from under | |
3115 | * us because we hold the mm_all_locks_mutex. | |
3116 | * | |
3117 | * We must however clear the bitflag before unlocking | |
bf181b9f | 3118 | * the vma so the users using the anon_vma->rb_root will |
7906d00c AA |
3119 | * never see our bitflag. |
3120 | * | |
3121 | * No need of atomic instructions here, head.next | |
3122 | * can't change from under us until we release the | |
5a505085 | 3123 | * anon_vma->root->rwsem. |
7906d00c AA |
3124 | */ |
3125 | if (!__test_and_clear_bit(0, (unsigned long *) | |
bf181b9f | 3126 | &anon_vma->root->rb_root.rb_node)) |
7906d00c | 3127 | BUG(); |
08b52706 | 3128 | anon_vma_unlock_write(anon_vma); |
7906d00c AA |
3129 | } |
3130 | } | |
3131 | ||
3132 | static void vm_unlock_mapping(struct address_space *mapping) | |
3133 | { | |
3134 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
3135 | /* | |
3136 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
3137 | * because we hold the mm_all_locks_mutex. | |
3138 | */ | |
3d48ae45 | 3139 | mutex_unlock(&mapping->i_mmap_mutex); |
7906d00c AA |
3140 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
3141 | &mapping->flags)) | |
3142 | BUG(); | |
3143 | } | |
3144 | } | |
3145 | ||
3146 | /* | |
3147 | * The mmap_sem cannot be released by the caller until | |
3148 | * mm_drop_all_locks() returns. | |
3149 | */ | |
3150 | void mm_drop_all_locks(struct mm_struct *mm) | |
3151 | { | |
3152 | struct vm_area_struct *vma; | |
5beb4930 | 3153 | struct anon_vma_chain *avc; |
7906d00c AA |
3154 | |
3155 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
3156 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
3157 | ||
3158 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
3159 | if (vma->anon_vma) | |
5beb4930 RR |
3160 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
3161 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
3162 | if (vma->vm_file && vma->vm_file->f_mapping) |
3163 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
3164 | } | |
3165 | ||
3166 | mutex_unlock(&mm_all_locks_mutex); | |
3167 | } | |
8feae131 DH |
3168 | |
3169 | /* | |
3170 | * initialise the VMA slab | |
3171 | */ | |
3172 | void __init mmap_init(void) | |
3173 | { | |
00a62ce9 KM |
3174 | int ret; |
3175 | ||
3176 | ret = percpu_counter_init(&vm_committed_as, 0); | |
3177 | VM_BUG_ON(ret); | |
8feae131 | 3178 | } |
c9b1d098 AS |
3179 | |
3180 | /* | |
3181 | * Initialise sysctl_user_reserve_kbytes. | |
3182 | * | |
3183 | * This is intended to prevent a user from starting a single memory hogging | |
3184 | * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER | |
3185 | * mode. | |
3186 | * | |
3187 | * The default value is min(3% of free memory, 128MB) | |
3188 | * 128MB is enough to recover with sshd/login, bash, and top/kill. | |
3189 | */ | |
1640879a | 3190 | static int init_user_reserve(void) |
c9b1d098 AS |
3191 | { |
3192 | unsigned long free_kbytes; | |
3193 | ||
3194 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3195 | ||
3196 | sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); | |
3197 | return 0; | |
3198 | } | |
a64fb3cd | 3199 | subsys_initcall(init_user_reserve); |
4eeab4f5 AS |
3200 | |
3201 | /* | |
3202 | * Initialise sysctl_admin_reserve_kbytes. | |
3203 | * | |
3204 | * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin | |
3205 | * to log in and kill a memory hogging process. | |
3206 | * | |
3207 | * Systems with more than 256MB will reserve 8MB, enough to recover | |
3208 | * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will | |
3209 | * only reserve 3% of free pages by default. | |
3210 | */ | |
1640879a | 3211 | static int init_admin_reserve(void) |
4eeab4f5 AS |
3212 | { |
3213 | unsigned long free_kbytes; | |
3214 | ||
3215 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3216 | ||
3217 | sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); | |
3218 | return 0; | |
3219 | } | |
a64fb3cd | 3220 | subsys_initcall(init_admin_reserve); |
1640879a AS |
3221 | |
3222 | /* | |
3223 | * Reinititalise user and admin reserves if memory is added or removed. | |
3224 | * | |
3225 | * The default user reserve max is 128MB, and the default max for the | |
3226 | * admin reserve is 8MB. These are usually, but not always, enough to | |
3227 | * enable recovery from a memory hogging process using login/sshd, a shell, | |
3228 | * and tools like top. It may make sense to increase or even disable the | |
3229 | * reserve depending on the existence of swap or variations in the recovery | |
3230 | * tools. So, the admin may have changed them. | |
3231 | * | |
3232 | * If memory is added and the reserves have been eliminated or increased above | |
3233 | * the default max, then we'll trust the admin. | |
3234 | * | |
3235 | * If memory is removed and there isn't enough free memory, then we | |
3236 | * need to reset the reserves. | |
3237 | * | |
3238 | * Otherwise keep the reserve set by the admin. | |
3239 | */ | |
3240 | static int reserve_mem_notifier(struct notifier_block *nb, | |
3241 | unsigned long action, void *data) | |
3242 | { | |
3243 | unsigned long tmp, free_kbytes; | |
3244 | ||
3245 | switch (action) { | |
3246 | case MEM_ONLINE: | |
3247 | /* Default max is 128MB. Leave alone if modified by operator. */ | |
3248 | tmp = sysctl_user_reserve_kbytes; | |
3249 | if (0 < tmp && tmp < (1UL << 17)) | |
3250 | init_user_reserve(); | |
3251 | ||
3252 | /* Default max is 8MB. Leave alone if modified by operator. */ | |
3253 | tmp = sysctl_admin_reserve_kbytes; | |
3254 | if (0 < tmp && tmp < (1UL << 13)) | |
3255 | init_admin_reserve(); | |
3256 | ||
3257 | break; | |
3258 | case MEM_OFFLINE: | |
3259 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); | |
3260 | ||
3261 | if (sysctl_user_reserve_kbytes > free_kbytes) { | |
3262 | init_user_reserve(); | |
3263 | pr_info("vm.user_reserve_kbytes reset to %lu\n", | |
3264 | sysctl_user_reserve_kbytes); | |
3265 | } | |
3266 | ||
3267 | if (sysctl_admin_reserve_kbytes > free_kbytes) { | |
3268 | init_admin_reserve(); | |
3269 | pr_info("vm.admin_reserve_kbytes reset to %lu\n", | |
3270 | sysctl_admin_reserve_kbytes); | |
3271 | } | |
3272 | break; | |
3273 | default: | |
3274 | break; | |
3275 | } | |
3276 | return NOTIFY_OK; | |
3277 | } | |
3278 | ||
3279 | static struct notifier_block reserve_mem_nb = { | |
3280 | .notifier_call = reserve_mem_notifier, | |
3281 | }; | |
3282 | ||
3283 | static int __meminit init_reserve_notifier(void) | |
3284 | { | |
3285 | if (register_hotmemory_notifier(&reserve_mem_nb)) | |
b1de0d13 | 3286 | pr_err("Failed registering memory add/remove notifier for admin reserve\n"); |
1640879a AS |
3287 | |
3288 | return 0; | |
3289 | } | |
a64fb3cd | 3290 | subsys_initcall(init_reserve_notifier); |