Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mmap.c | |
3 | * | |
4 | * Written by obz. | |
5 | * | |
046c6884 | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
7 | */ |
8 | ||
9 | #include <linux/slab.h> | |
4af3c9cc | 10 | #include <linux/backing-dev.h> |
1da177e4 LT |
11 | #include <linux/mm.h> |
12 | #include <linux/shm.h> | |
13 | #include <linux/mman.h> | |
14 | #include <linux/pagemap.h> | |
15 | #include <linux/swap.h> | |
16 | #include <linux/syscalls.h> | |
c59ede7b | 17 | #include <linux/capability.h> |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/file.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/security.h> | |
23 | #include <linux/hugetlb.h> | |
24 | #include <linux/profile.h> | |
b95f1b31 | 25 | #include <linux/export.h> |
1da177e4 LT |
26 | #include <linux/mount.h> |
27 | #include <linux/mempolicy.h> | |
28 | #include <linux/rmap.h> | |
cddb8a5c | 29 | #include <linux/mmu_notifier.h> |
cdd6c482 | 30 | #include <linux/perf_event.h> |
120a795d | 31 | #include <linux/audit.h> |
b15d00b6 | 32 | #include <linux/khugepaged.h> |
2b144498 | 33 | #include <linux/uprobes.h> |
1da177e4 LT |
34 | |
35 | #include <asm/uaccess.h> | |
36 | #include <asm/cacheflush.h> | |
37 | #include <asm/tlb.h> | |
d6dd61c8 | 38 | #include <asm/mmu_context.h> |
1da177e4 | 39 | |
42b77728 JB |
40 | #include "internal.h" |
41 | ||
3a459756 KK |
42 | #ifndef arch_mmap_check |
43 | #define arch_mmap_check(addr, len, flags) (0) | |
44 | #endif | |
45 | ||
08e7d9b5 MS |
46 | #ifndef arch_rebalance_pgtables |
47 | #define arch_rebalance_pgtables(addr, len) (addr) | |
48 | #endif | |
49 | ||
e0da382c HD |
50 | static void unmap_region(struct mm_struct *mm, |
51 | struct vm_area_struct *vma, struct vm_area_struct *prev, | |
52 | unsigned long start, unsigned long end); | |
53 | ||
1da177e4 LT |
54 | /* description of effects of mapping type and prot in current implementation. |
55 | * this is due to the limited x86 page protection hardware. The expected | |
56 | * behavior is in parens: | |
57 | * | |
58 | * map_type prot | |
59 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC | |
60 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
61 | * w: (no) no w: (no) no w: (yes) yes w: (no) no | |
62 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
63 | * | |
64 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes | |
65 | * w: (no) no w: (no) no w: (copy) copy w: (no) no | |
66 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes | |
67 | * | |
68 | */ | |
69 | pgprot_t protection_map[16] = { | |
70 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, | |
71 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 | |
72 | }; | |
73 | ||
804af2cf HD |
74 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
75 | { | |
b845f313 DK |
76 | return __pgprot(pgprot_val(protection_map[vm_flags & |
77 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | | |
78 | pgprot_val(arch_vm_get_page_prot(vm_flags))); | |
804af2cf HD |
79 | } |
80 | EXPORT_SYMBOL(vm_get_page_prot); | |
81 | ||
34679d7e SL |
82 | int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
83 | int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ | |
c3d8c141 | 84 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
34679d7e SL |
85 | /* |
86 | * Make sure vm_committed_as in one cacheline and not cacheline shared with | |
87 | * other variables. It can be updated by several CPUs frequently. | |
88 | */ | |
89 | struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; | |
1da177e4 | 90 | |
997071bc S |
91 | /* |
92 | * The global memory commitment made in the system can be a metric | |
93 | * that can be used to drive ballooning decisions when Linux is hosted | |
94 | * as a guest. On Hyper-V, the host implements a policy engine for dynamically | |
95 | * balancing memory across competing virtual machines that are hosted. | |
96 | * Several metrics drive this policy engine including the guest reported | |
97 | * memory commitment. | |
98 | */ | |
99 | unsigned long vm_memory_committed(void) | |
100 | { | |
101 | return percpu_counter_read_positive(&vm_committed_as); | |
102 | } | |
103 | EXPORT_SYMBOL_GPL(vm_memory_committed); | |
104 | ||
1da177e4 LT |
105 | /* |
106 | * Check that a process has enough memory to allocate a new virtual | |
107 | * mapping. 0 means there is enough memory for the allocation to | |
108 | * succeed and -ENOMEM implies there is not. | |
109 | * | |
110 | * We currently support three overcommit policies, which are set via the | |
111 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
112 | * | |
113 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
114 | * Additional code 2002 Jul 20 by Robert Love. | |
115 | * | |
116 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
117 | * | |
118 | * Note this is a helper function intended to be used by LSMs which | |
119 | * wish to use this logic. | |
120 | */ | |
34b4e4aa | 121 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1da177e4 LT |
122 | { |
123 | unsigned long free, allowed; | |
124 | ||
125 | vm_acct_memory(pages); | |
126 | ||
127 | /* | |
128 | * Sometimes we want to use more memory than we have | |
129 | */ | |
130 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
131 | return 0; | |
132 | ||
133 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
c15bef30 DF |
134 | free = global_page_state(NR_FREE_PAGES); |
135 | free += global_page_state(NR_FILE_PAGES); | |
136 | ||
137 | /* | |
138 | * shmem pages shouldn't be counted as free in this | |
139 | * case, they can't be purged, only swapped out, and | |
140 | * that won't affect the overall amount of available | |
141 | * memory in the system. | |
142 | */ | |
143 | free -= global_page_state(NR_SHMEM); | |
1da177e4 | 144 | |
1da177e4 LT |
145 | free += nr_swap_pages; |
146 | ||
147 | /* | |
148 | * Any slabs which are created with the | |
149 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
150 | * which are reclaimable, under pressure. The dentry | |
151 | * cache and most inode caches should fall into this | |
152 | */ | |
972d1a7b | 153 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 | 154 | |
6d9f7839 HA |
155 | /* |
156 | * Leave reserved pages. The pages are not for anonymous pages. | |
157 | */ | |
c15bef30 | 158 | if (free <= totalreserve_pages) |
6d9f7839 HA |
159 | goto error; |
160 | else | |
c15bef30 | 161 | free -= totalreserve_pages; |
6d9f7839 HA |
162 | |
163 | /* | |
164 | * Leave the last 3% for root | |
165 | */ | |
1da177e4 | 166 | if (!cap_sys_admin) |
c15bef30 | 167 | free -= free / 32; |
1da177e4 LT |
168 | |
169 | if (free > pages) | |
170 | return 0; | |
6d9f7839 HA |
171 | |
172 | goto error; | |
1da177e4 LT |
173 | } |
174 | ||
175 | allowed = (totalram_pages - hugetlb_total_pages()) | |
176 | * sysctl_overcommit_ratio / 100; | |
177 | /* | |
178 | * Leave the last 3% for root | |
179 | */ | |
180 | if (!cap_sys_admin) | |
181 | allowed -= allowed / 32; | |
182 | allowed += total_swap_pages; | |
183 | ||
184 | /* Don't let a single process grow too big: | |
185 | leave 3% of the size of this process for other processes */ | |
731572d3 AC |
186 | if (mm) |
187 | allowed -= mm->total_vm / 32; | |
1da177e4 | 188 | |
00a62ce9 | 189 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1da177e4 | 190 | return 0; |
6d9f7839 | 191 | error: |
1da177e4 LT |
192 | vm_unacct_memory(pages); |
193 | ||
194 | return -ENOMEM; | |
195 | } | |
196 | ||
1da177e4 | 197 | /* |
3d48ae45 | 198 | * Requires inode->i_mapping->i_mmap_mutex |
1da177e4 LT |
199 | */ |
200 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, | |
201 | struct file *file, struct address_space *mapping) | |
202 | { | |
203 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 204 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
205 | if (vma->vm_flags & VM_SHARED) |
206 | mapping->i_mmap_writable--; | |
207 | ||
208 | flush_dcache_mmap_lock(mapping); | |
209 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
6b2dbba8 | 210 | list_del_init(&vma->shared.nonlinear); |
1da177e4 | 211 | else |
6b2dbba8 | 212 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
1da177e4 LT |
213 | flush_dcache_mmap_unlock(mapping); |
214 | } | |
215 | ||
216 | /* | |
6b2dbba8 | 217 | * Unlink a file-based vm structure from its interval tree, to hide |
a8fb5618 | 218 | * vma from rmap and vmtruncate before freeing its page tables. |
1da177e4 | 219 | */ |
a8fb5618 | 220 | void unlink_file_vma(struct vm_area_struct *vma) |
1da177e4 LT |
221 | { |
222 | struct file *file = vma->vm_file; | |
223 | ||
1da177e4 LT |
224 | if (file) { |
225 | struct address_space *mapping = file->f_mapping; | |
3d48ae45 | 226 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 227 | __remove_shared_vm_struct(vma, file, mapping); |
3d48ae45 | 228 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 229 | } |
a8fb5618 HD |
230 | } |
231 | ||
232 | /* | |
233 | * Close a vm structure and free it, returning the next. | |
234 | */ | |
235 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) | |
236 | { | |
237 | struct vm_area_struct *next = vma->vm_next; | |
238 | ||
a8fb5618 | 239 | might_sleep(); |
1da177e4 LT |
240 | if (vma->vm_ops && vma->vm_ops->close) |
241 | vma->vm_ops->close(vma); | |
e9714acf | 242 | if (vma->vm_file) |
a8fb5618 | 243 | fput(vma->vm_file); |
f0be3d32 | 244 | mpol_put(vma_policy(vma)); |
1da177e4 | 245 | kmem_cache_free(vm_area_cachep, vma); |
a8fb5618 | 246 | return next; |
1da177e4 LT |
247 | } |
248 | ||
e4eb1ff6 LT |
249 | static unsigned long do_brk(unsigned long addr, unsigned long len); |
250 | ||
6a6160a7 | 251 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
1da177e4 LT |
252 | { |
253 | unsigned long rlim, retval; | |
254 | unsigned long newbrk, oldbrk; | |
255 | struct mm_struct *mm = current->mm; | |
a5b4592c | 256 | unsigned long min_brk; |
1da177e4 LT |
257 | |
258 | down_write(&mm->mmap_sem); | |
259 | ||
a5b4592c | 260 | #ifdef CONFIG_COMPAT_BRK |
5520e894 JK |
261 | /* |
262 | * CONFIG_COMPAT_BRK can still be overridden by setting | |
263 | * randomize_va_space to 2, which will still cause mm->start_brk | |
264 | * to be arbitrarily shifted | |
265 | */ | |
4471a675 | 266 | if (current->brk_randomized) |
5520e894 JK |
267 | min_brk = mm->start_brk; |
268 | else | |
269 | min_brk = mm->end_data; | |
a5b4592c JK |
270 | #else |
271 | min_brk = mm->start_brk; | |
272 | #endif | |
273 | if (brk < min_brk) | |
1da177e4 | 274 | goto out; |
1e624196 RG |
275 | |
276 | /* | |
277 | * Check against rlimit here. If this check is done later after the test | |
278 | * of oldbrk with newbrk then it can escape the test and let the data | |
279 | * segment grow beyond its set limit the in case where the limit is | |
280 | * not page aligned -Ram Gupta | |
281 | */ | |
59e99e5b | 282 | rlim = rlimit(RLIMIT_DATA); |
c1d171a0 JK |
283 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
284 | (mm->end_data - mm->start_data) > rlim) | |
1e624196 RG |
285 | goto out; |
286 | ||
1da177e4 LT |
287 | newbrk = PAGE_ALIGN(brk); |
288 | oldbrk = PAGE_ALIGN(mm->brk); | |
289 | if (oldbrk == newbrk) | |
290 | goto set_brk; | |
291 | ||
292 | /* Always allow shrinking brk. */ | |
293 | if (brk <= mm->brk) { | |
294 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) | |
295 | goto set_brk; | |
296 | goto out; | |
297 | } | |
298 | ||
1da177e4 LT |
299 | /* Check against existing mmap mappings. */ |
300 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) | |
301 | goto out; | |
302 | ||
303 | /* Ok, looks good - let it rip. */ | |
304 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) | |
305 | goto out; | |
306 | set_brk: | |
307 | mm->brk = brk; | |
308 | out: | |
309 | retval = mm->brk; | |
310 | up_write(&mm->mmap_sem); | |
311 | return retval; | |
312 | } | |
313 | ||
ed8ea815 | 314 | #ifdef CONFIG_DEBUG_VM_RB |
1da177e4 LT |
315 | static int browse_rb(struct rb_root *root) |
316 | { | |
317 | int i = 0, j; | |
318 | struct rb_node *nd, *pn = NULL; | |
319 | unsigned long prev = 0, pend = 0; | |
320 | ||
321 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { | |
322 | struct vm_area_struct *vma; | |
323 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); | |
324 | if (vma->vm_start < prev) | |
325 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; | |
326 | if (vma->vm_start < pend) | |
327 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); | |
328 | if (vma->vm_start > vma->vm_end) | |
329 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); | |
330 | i++; | |
331 | pn = nd; | |
d1af65d1 DM |
332 | prev = vma->vm_start; |
333 | pend = vma->vm_end; | |
1da177e4 LT |
334 | } |
335 | j = 0; | |
336 | for (nd = pn; nd; nd = rb_prev(nd)) { | |
337 | j++; | |
338 | } | |
339 | if (i != j) | |
340 | printk("backwards %d, forwards %d\n", j, i), i = 0; | |
341 | return i; | |
342 | } | |
343 | ||
344 | void validate_mm(struct mm_struct *mm) | |
345 | { | |
346 | int bug = 0; | |
347 | int i = 0; | |
ed8ea815 ML |
348 | struct vm_area_struct *vma = mm->mmap; |
349 | while (vma) { | |
350 | struct anon_vma_chain *avc; | |
63c3b902 | 351 | vma_lock_anon_vma(vma); |
ed8ea815 ML |
352 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
353 | anon_vma_interval_tree_verify(avc); | |
63c3b902 | 354 | vma_unlock_anon_vma(vma); |
ed8ea815 | 355 | vma = vma->vm_next; |
1da177e4 LT |
356 | i++; |
357 | } | |
358 | if (i != mm->map_count) | |
359 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; | |
360 | i = browse_rb(&mm->mm_rb); | |
361 | if (i != mm->map_count) | |
362 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; | |
46a350ef | 363 | BUG_ON(bug); |
1da177e4 LT |
364 | } |
365 | #else | |
366 | #define validate_mm(mm) do { } while (0) | |
367 | #endif | |
368 | ||
bf181b9f ML |
369 | /* |
370 | * vma has some anon_vma assigned, and is already inserted on that | |
371 | * anon_vma's interval trees. | |
372 | * | |
373 | * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the | |
374 | * vma must be removed from the anon_vma's interval trees using | |
375 | * anon_vma_interval_tree_pre_update_vma(). | |
376 | * | |
377 | * After the update, the vma will be reinserted using | |
378 | * anon_vma_interval_tree_post_update_vma(). | |
379 | * | |
380 | * The entire update must be protected by exclusive mmap_sem and by | |
381 | * the root anon_vma's mutex. | |
382 | */ | |
383 | static inline void | |
384 | anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) | |
385 | { | |
386 | struct anon_vma_chain *avc; | |
387 | ||
388 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
389 | anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); | |
390 | } | |
391 | ||
392 | static inline void | |
393 | anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) | |
394 | { | |
395 | struct anon_vma_chain *avc; | |
396 | ||
397 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) | |
398 | anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); | |
399 | } | |
400 | ||
6597d783 HD |
401 | static int find_vma_links(struct mm_struct *mm, unsigned long addr, |
402 | unsigned long end, struct vm_area_struct **pprev, | |
403 | struct rb_node ***rb_link, struct rb_node **rb_parent) | |
1da177e4 | 404 | { |
6597d783 | 405 | struct rb_node **__rb_link, *__rb_parent, *rb_prev; |
1da177e4 LT |
406 | |
407 | __rb_link = &mm->mm_rb.rb_node; | |
408 | rb_prev = __rb_parent = NULL; | |
1da177e4 LT |
409 | |
410 | while (*__rb_link) { | |
411 | struct vm_area_struct *vma_tmp; | |
412 | ||
413 | __rb_parent = *__rb_link; | |
414 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); | |
415 | ||
416 | if (vma_tmp->vm_end > addr) { | |
6597d783 HD |
417 | /* Fail if an existing vma overlaps the area */ |
418 | if (vma_tmp->vm_start < end) | |
419 | return -ENOMEM; | |
1da177e4 LT |
420 | __rb_link = &__rb_parent->rb_left; |
421 | } else { | |
422 | rb_prev = __rb_parent; | |
423 | __rb_link = &__rb_parent->rb_right; | |
424 | } | |
425 | } | |
426 | ||
427 | *pprev = NULL; | |
428 | if (rb_prev) | |
429 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); | |
430 | *rb_link = __rb_link; | |
431 | *rb_parent = __rb_parent; | |
6597d783 | 432 | return 0; |
1da177e4 LT |
433 | } |
434 | ||
1da177e4 LT |
435 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
436 | struct rb_node **rb_link, struct rb_node *rb_parent) | |
437 | { | |
438 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); | |
439 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); | |
440 | } | |
441 | ||
cb8f488c | 442 | static void __vma_link_file(struct vm_area_struct *vma) |
1da177e4 | 443 | { |
48aae425 | 444 | struct file *file; |
1da177e4 LT |
445 | |
446 | file = vma->vm_file; | |
447 | if (file) { | |
448 | struct address_space *mapping = file->f_mapping; | |
449 | ||
450 | if (vma->vm_flags & VM_DENYWRITE) | |
d3ac7f89 | 451 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
1da177e4 LT |
452 | if (vma->vm_flags & VM_SHARED) |
453 | mapping->i_mmap_writable++; | |
454 | ||
455 | flush_dcache_mmap_lock(mapping); | |
456 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) | |
457 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); | |
458 | else | |
6b2dbba8 | 459 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
1da177e4 LT |
460 | flush_dcache_mmap_unlock(mapping); |
461 | } | |
462 | } | |
463 | ||
464 | static void | |
465 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
466 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
467 | struct rb_node *rb_parent) | |
468 | { | |
469 | __vma_link_list(mm, vma, prev, rb_parent); | |
470 | __vma_link_rb(mm, vma, rb_link, rb_parent); | |
1da177e4 LT |
471 | } |
472 | ||
473 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, | |
474 | struct vm_area_struct *prev, struct rb_node **rb_link, | |
475 | struct rb_node *rb_parent) | |
476 | { | |
477 | struct address_space *mapping = NULL; | |
478 | ||
479 | if (vma->vm_file) | |
480 | mapping = vma->vm_file->f_mapping; | |
481 | ||
97a89413 | 482 | if (mapping) |
3d48ae45 | 483 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 LT |
484 | |
485 | __vma_link(mm, vma, prev, rb_link, rb_parent); | |
486 | __vma_link_file(vma); | |
487 | ||
1da177e4 | 488 | if (mapping) |
3d48ae45 | 489 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
490 | |
491 | mm->map_count++; | |
492 | validate_mm(mm); | |
493 | } | |
494 | ||
495 | /* | |
88f6b4c3 | 496 | * Helper for vma_adjust() in the split_vma insert case: insert a vma into the |
6b2dbba8 | 497 | * mm's list and rbtree. It has already been inserted into the interval tree. |
1da177e4 | 498 | */ |
48aae425 | 499 | static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 500 | { |
6597d783 | 501 | struct vm_area_struct *prev; |
48aae425 | 502 | struct rb_node **rb_link, *rb_parent; |
1da177e4 | 503 | |
6597d783 HD |
504 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
505 | &prev, &rb_link, &rb_parent)) | |
506 | BUG(); | |
1da177e4 LT |
507 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
508 | mm->map_count++; | |
509 | } | |
510 | ||
511 | static inline void | |
512 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, | |
513 | struct vm_area_struct *prev) | |
514 | { | |
297c5eee LT |
515 | struct vm_area_struct *next = vma->vm_next; |
516 | ||
517 | prev->vm_next = next; | |
518 | if (next) | |
519 | next->vm_prev = prev; | |
1da177e4 LT |
520 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
521 | if (mm->mmap_cache == vma) | |
522 | mm->mmap_cache = prev; | |
523 | } | |
524 | ||
525 | /* | |
526 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that | |
527 | * is already present in an i_mmap tree without adjusting the tree. | |
528 | * The following helper function should be used when such adjustments | |
529 | * are necessary. The "insert" vma (if any) is to be inserted | |
530 | * before we drop the necessary locks. | |
531 | */ | |
5beb4930 | 532 | int vma_adjust(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
533 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
534 | { | |
535 | struct mm_struct *mm = vma->vm_mm; | |
536 | struct vm_area_struct *next = vma->vm_next; | |
537 | struct vm_area_struct *importer = NULL; | |
538 | struct address_space *mapping = NULL; | |
6b2dbba8 | 539 | struct rb_root *root = NULL; |
012f1800 | 540 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 541 | struct file *file = vma->vm_file; |
1da177e4 LT |
542 | long adjust_next = 0; |
543 | int remove_next = 0; | |
544 | ||
545 | if (next && !insert) { | |
287d97ac LT |
546 | struct vm_area_struct *exporter = NULL; |
547 | ||
1da177e4 LT |
548 | if (end >= next->vm_end) { |
549 | /* | |
550 | * vma expands, overlapping all the next, and | |
551 | * perhaps the one after too (mprotect case 6). | |
552 | */ | |
553 | again: remove_next = 1 + (end > next->vm_end); | |
554 | end = next->vm_end; | |
287d97ac | 555 | exporter = next; |
1da177e4 LT |
556 | importer = vma; |
557 | } else if (end > next->vm_start) { | |
558 | /* | |
559 | * vma expands, overlapping part of the next: | |
560 | * mprotect case 5 shifting the boundary up. | |
561 | */ | |
562 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; | |
287d97ac | 563 | exporter = next; |
1da177e4 LT |
564 | importer = vma; |
565 | } else if (end < vma->vm_end) { | |
566 | /* | |
567 | * vma shrinks, and !insert tells it's not | |
568 | * split_vma inserting another: so it must be | |
569 | * mprotect case 4 shifting the boundary down. | |
570 | */ | |
571 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); | |
287d97ac | 572 | exporter = vma; |
1da177e4 LT |
573 | importer = next; |
574 | } | |
1da177e4 | 575 | |
5beb4930 RR |
576 | /* |
577 | * Easily overlooked: when mprotect shifts the boundary, | |
578 | * make sure the expanding vma has anon_vma set if the | |
579 | * shrinking vma had, to cover any anon pages imported. | |
580 | */ | |
287d97ac LT |
581 | if (exporter && exporter->anon_vma && !importer->anon_vma) { |
582 | if (anon_vma_clone(importer, exporter)) | |
5beb4930 | 583 | return -ENOMEM; |
287d97ac | 584 | importer->anon_vma = exporter->anon_vma; |
5beb4930 RR |
585 | } |
586 | } | |
587 | ||
1da177e4 LT |
588 | if (file) { |
589 | mapping = file->f_mapping; | |
682968e0 | 590 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
1da177e4 | 591 | root = &mapping->i_mmap; |
cbc91f71 | 592 | uprobe_munmap(vma, vma->vm_start, vma->vm_end); |
682968e0 SD |
593 | |
594 | if (adjust_next) | |
cbc91f71 SD |
595 | uprobe_munmap(next, next->vm_start, |
596 | next->vm_end); | |
682968e0 SD |
597 | } |
598 | ||
3d48ae45 | 599 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 | 600 | if (insert) { |
1da177e4 | 601 | /* |
6b2dbba8 | 602 | * Put into interval tree now, so instantiated pages |
1da177e4 LT |
603 | * are visible to arm/parisc __flush_dcache_page |
604 | * throughout; but we cannot insert into address | |
605 | * space until vma start or end is updated. | |
606 | */ | |
607 | __vma_link_file(insert); | |
608 | } | |
609 | } | |
610 | ||
94fcc585 AA |
611 | vma_adjust_trans_huge(vma, start, end, adjust_next); |
612 | ||
bf181b9f ML |
613 | anon_vma = vma->anon_vma; |
614 | if (!anon_vma && adjust_next) | |
615 | anon_vma = next->anon_vma; | |
616 | if (anon_vma) { | |
ca42b26a ML |
617 | VM_BUG_ON(adjust_next && next->anon_vma && |
618 | anon_vma != next->anon_vma); | |
012f1800 | 619 | anon_vma_lock(anon_vma); |
bf181b9f ML |
620 | anon_vma_interval_tree_pre_update_vma(vma); |
621 | if (adjust_next) | |
622 | anon_vma_interval_tree_pre_update_vma(next); | |
623 | } | |
012f1800 | 624 | |
1da177e4 LT |
625 | if (root) { |
626 | flush_dcache_mmap_lock(mapping); | |
6b2dbba8 | 627 | vma_interval_tree_remove(vma, root); |
1da177e4 | 628 | if (adjust_next) |
6b2dbba8 | 629 | vma_interval_tree_remove(next, root); |
1da177e4 LT |
630 | } |
631 | ||
632 | vma->vm_start = start; | |
633 | vma->vm_end = end; | |
634 | vma->vm_pgoff = pgoff; | |
635 | if (adjust_next) { | |
636 | next->vm_start += adjust_next << PAGE_SHIFT; | |
637 | next->vm_pgoff += adjust_next; | |
638 | } | |
639 | ||
640 | if (root) { | |
641 | if (adjust_next) | |
6b2dbba8 ML |
642 | vma_interval_tree_insert(next, root); |
643 | vma_interval_tree_insert(vma, root); | |
1da177e4 LT |
644 | flush_dcache_mmap_unlock(mapping); |
645 | } | |
646 | ||
647 | if (remove_next) { | |
648 | /* | |
649 | * vma_merge has merged next into vma, and needs | |
650 | * us to remove next before dropping the locks. | |
651 | */ | |
652 | __vma_unlink(mm, next, vma); | |
653 | if (file) | |
654 | __remove_shared_vm_struct(next, file, mapping); | |
1da177e4 LT |
655 | } else if (insert) { |
656 | /* | |
657 | * split_vma has split insert from vma, and needs | |
658 | * us to insert it before dropping the locks | |
659 | * (it may either follow vma or precede it). | |
660 | */ | |
661 | __insert_vm_struct(mm, insert); | |
662 | } | |
663 | ||
bf181b9f ML |
664 | if (anon_vma) { |
665 | anon_vma_interval_tree_post_update_vma(vma); | |
666 | if (adjust_next) | |
667 | anon_vma_interval_tree_post_update_vma(next); | |
012f1800 | 668 | anon_vma_unlock(anon_vma); |
bf181b9f | 669 | } |
1da177e4 | 670 | if (mapping) |
3d48ae45 | 671 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 | 672 | |
2b144498 | 673 | if (root) { |
7b2d81d4 | 674 | uprobe_mmap(vma); |
2b144498 SD |
675 | |
676 | if (adjust_next) | |
7b2d81d4 | 677 | uprobe_mmap(next); |
2b144498 SD |
678 | } |
679 | ||
1da177e4 | 680 | if (remove_next) { |
925d1c40 | 681 | if (file) { |
cbc91f71 | 682 | uprobe_munmap(next, next->vm_start, next->vm_end); |
1da177e4 | 683 | fput(file); |
925d1c40 | 684 | } |
5beb4930 RR |
685 | if (next->anon_vma) |
686 | anon_vma_merge(vma, next); | |
1da177e4 | 687 | mm->map_count--; |
f0be3d32 | 688 | mpol_put(vma_policy(next)); |
1da177e4 LT |
689 | kmem_cache_free(vm_area_cachep, next); |
690 | /* | |
691 | * In mprotect's case 6 (see comments on vma_merge), | |
692 | * we must remove another next too. It would clutter | |
693 | * up the code too much to do both in one go. | |
694 | */ | |
695 | if (remove_next == 2) { | |
696 | next = vma->vm_next; | |
697 | goto again; | |
698 | } | |
699 | } | |
2b144498 | 700 | if (insert && file) |
7b2d81d4 | 701 | uprobe_mmap(insert); |
1da177e4 LT |
702 | |
703 | validate_mm(mm); | |
5beb4930 RR |
704 | |
705 | return 0; | |
1da177e4 LT |
706 | } |
707 | ||
708 | /* | |
709 | * If the vma has a ->close operation then the driver probably needs to release | |
710 | * per-vma resources, so we don't attempt to merge those. | |
711 | */ | |
1da177e4 LT |
712 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
713 | struct file *file, unsigned long vm_flags) | |
714 | { | |
0b173bc4 | 715 | if (vma->vm_flags ^ vm_flags) |
1da177e4 LT |
716 | return 0; |
717 | if (vma->vm_file != file) | |
718 | return 0; | |
719 | if (vma->vm_ops && vma->vm_ops->close) | |
720 | return 0; | |
721 | return 1; | |
722 | } | |
723 | ||
724 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, | |
965f55de SL |
725 | struct anon_vma *anon_vma2, |
726 | struct vm_area_struct *vma) | |
1da177e4 | 727 | { |
965f55de SL |
728 | /* |
729 | * The list_is_singular() test is to avoid merging VMA cloned from | |
730 | * parents. This can improve scalability caused by anon_vma lock. | |
731 | */ | |
732 | if ((!anon_vma1 || !anon_vma2) && (!vma || | |
733 | list_is_singular(&vma->anon_vma_chain))) | |
734 | return 1; | |
735 | return anon_vma1 == anon_vma2; | |
1da177e4 LT |
736 | } |
737 | ||
738 | /* | |
739 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
740 | * in front of (at a lower virtual address and file offset than) the vma. | |
741 | * | |
742 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
743 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
744 | * | |
745 | * We don't check here for the merged mmap wrapping around the end of pagecache | |
746 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which | |
747 | * wrap, nor mmaps which cover the final page at index -1UL. | |
748 | */ | |
749 | static int | |
750 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, | |
751 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
752 | { | |
753 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 754 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
755 | if (vma->vm_pgoff == vm_pgoff) |
756 | return 1; | |
757 | } | |
758 | return 0; | |
759 | } | |
760 | ||
761 | /* | |
762 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) | |
763 | * beyond (at a higher virtual address and file offset than) the vma. | |
764 | * | |
765 | * We cannot merge two vmas if they have differently assigned (non-NULL) | |
766 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. | |
767 | */ | |
768 | static int | |
769 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, | |
770 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) | |
771 | { | |
772 | if (is_mergeable_vma(vma, file, vm_flags) && | |
965f55de | 773 | is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { |
1da177e4 LT |
774 | pgoff_t vm_pglen; |
775 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
776 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) | |
777 | return 1; | |
778 | } | |
779 | return 0; | |
780 | } | |
781 | ||
782 | /* | |
783 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out | |
784 | * whether that can be merged with its predecessor or its successor. | |
785 | * Or both (it neatly fills a hole). | |
786 | * | |
787 | * In most cases - when called for mmap, brk or mremap - [addr,end) is | |
788 | * certain not to be mapped by the time vma_merge is called; but when | |
789 | * called for mprotect, it is certain to be already mapped (either at | |
790 | * an offset within prev, or at the start of next), and the flags of | |
791 | * this area are about to be changed to vm_flags - and the no-change | |
792 | * case has already been eliminated. | |
793 | * | |
794 | * The following mprotect cases have to be considered, where AAAA is | |
795 | * the area passed down from mprotect_fixup, never extending beyond one | |
796 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: | |
797 | * | |
798 | * AAAA AAAA AAAA AAAA | |
799 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX | |
800 | * cannot merge might become might become might become | |
801 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or | |
802 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or | |
803 | * mremap move: PPPPNNNNNNNN 8 | |
804 | * AAAA | |
805 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN | |
806 | * might become case 1 below case 2 below case 3 below | |
807 | * | |
808 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: | |
809 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. | |
810 | */ | |
811 | struct vm_area_struct *vma_merge(struct mm_struct *mm, | |
812 | struct vm_area_struct *prev, unsigned long addr, | |
813 | unsigned long end, unsigned long vm_flags, | |
814 | struct anon_vma *anon_vma, struct file *file, | |
815 | pgoff_t pgoff, struct mempolicy *policy) | |
816 | { | |
817 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; | |
818 | struct vm_area_struct *area, *next; | |
5beb4930 | 819 | int err; |
1da177e4 LT |
820 | |
821 | /* | |
822 | * We later require that vma->vm_flags == vm_flags, | |
823 | * so this tests vma->vm_flags & VM_SPECIAL, too. | |
824 | */ | |
825 | if (vm_flags & VM_SPECIAL) | |
826 | return NULL; | |
827 | ||
828 | if (prev) | |
829 | next = prev->vm_next; | |
830 | else | |
831 | next = mm->mmap; | |
832 | area = next; | |
833 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ | |
834 | next = next->vm_next; | |
835 | ||
836 | /* | |
837 | * Can it merge with the predecessor? | |
838 | */ | |
839 | if (prev && prev->vm_end == addr && | |
840 | mpol_equal(vma_policy(prev), policy) && | |
841 | can_vma_merge_after(prev, vm_flags, | |
842 | anon_vma, file, pgoff)) { | |
843 | /* | |
844 | * OK, it can. Can we now merge in the successor as well? | |
845 | */ | |
846 | if (next && end == next->vm_start && | |
847 | mpol_equal(policy, vma_policy(next)) && | |
848 | can_vma_merge_before(next, vm_flags, | |
849 | anon_vma, file, pgoff+pglen) && | |
850 | is_mergeable_anon_vma(prev->anon_vma, | |
965f55de | 851 | next->anon_vma, NULL)) { |
1da177e4 | 852 | /* cases 1, 6 */ |
5beb4930 | 853 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
854 | next->vm_end, prev->vm_pgoff, NULL); |
855 | } else /* cases 2, 5, 7 */ | |
5beb4930 | 856 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 | 857 | end, prev->vm_pgoff, NULL); |
5beb4930 RR |
858 | if (err) |
859 | return NULL; | |
b15d00b6 | 860 | khugepaged_enter_vma_merge(prev); |
1da177e4 LT |
861 | return prev; |
862 | } | |
863 | ||
864 | /* | |
865 | * Can this new request be merged in front of next? | |
866 | */ | |
867 | if (next && end == next->vm_start && | |
868 | mpol_equal(policy, vma_policy(next)) && | |
869 | can_vma_merge_before(next, vm_flags, | |
870 | anon_vma, file, pgoff+pglen)) { | |
871 | if (prev && addr < prev->vm_end) /* case 4 */ | |
5beb4930 | 872 | err = vma_adjust(prev, prev->vm_start, |
1da177e4 LT |
873 | addr, prev->vm_pgoff, NULL); |
874 | else /* cases 3, 8 */ | |
5beb4930 | 875 | err = vma_adjust(area, addr, next->vm_end, |
1da177e4 | 876 | next->vm_pgoff - pglen, NULL); |
5beb4930 RR |
877 | if (err) |
878 | return NULL; | |
b15d00b6 | 879 | khugepaged_enter_vma_merge(area); |
1da177e4 LT |
880 | return area; |
881 | } | |
882 | ||
883 | return NULL; | |
884 | } | |
885 | ||
d0e9fe17 LT |
886 | /* |
887 | * Rough compatbility check to quickly see if it's even worth looking | |
888 | * at sharing an anon_vma. | |
889 | * | |
890 | * They need to have the same vm_file, and the flags can only differ | |
891 | * in things that mprotect may change. | |
892 | * | |
893 | * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that | |
894 | * we can merge the two vma's. For example, we refuse to merge a vma if | |
895 | * there is a vm_ops->close() function, because that indicates that the | |
896 | * driver is doing some kind of reference counting. But that doesn't | |
897 | * really matter for the anon_vma sharing case. | |
898 | */ | |
899 | static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) | |
900 | { | |
901 | return a->vm_end == b->vm_start && | |
902 | mpol_equal(vma_policy(a), vma_policy(b)) && | |
903 | a->vm_file == b->vm_file && | |
904 | !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && | |
905 | b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); | |
906 | } | |
907 | ||
908 | /* | |
909 | * Do some basic sanity checking to see if we can re-use the anon_vma | |
910 | * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be | |
911 | * the same as 'old', the other will be the new one that is trying | |
912 | * to share the anon_vma. | |
913 | * | |
914 | * NOTE! This runs with mm_sem held for reading, so it is possible that | |
915 | * the anon_vma of 'old' is concurrently in the process of being set up | |
916 | * by another page fault trying to merge _that_. But that's ok: if it | |
917 | * is being set up, that automatically means that it will be a singleton | |
918 | * acceptable for merging, so we can do all of this optimistically. But | |
919 | * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. | |
920 | * | |
921 | * IOW: that the "list_is_singular()" test on the anon_vma_chain only | |
922 | * matters for the 'stable anon_vma' case (ie the thing we want to avoid | |
923 | * is to return an anon_vma that is "complex" due to having gone through | |
924 | * a fork). | |
925 | * | |
926 | * We also make sure that the two vma's are compatible (adjacent, | |
927 | * and with the same memory policies). That's all stable, even with just | |
928 | * a read lock on the mm_sem. | |
929 | */ | |
930 | static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) | |
931 | { | |
932 | if (anon_vma_compatible(a, b)) { | |
933 | struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); | |
934 | ||
935 | if (anon_vma && list_is_singular(&old->anon_vma_chain)) | |
936 | return anon_vma; | |
937 | } | |
938 | return NULL; | |
939 | } | |
940 | ||
1da177e4 LT |
941 | /* |
942 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check | |
943 | * neighbouring vmas for a suitable anon_vma, before it goes off | |
944 | * to allocate a new anon_vma. It checks because a repetitive | |
945 | * sequence of mprotects and faults may otherwise lead to distinct | |
946 | * anon_vmas being allocated, preventing vma merge in subsequent | |
947 | * mprotect. | |
948 | */ | |
949 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) | |
950 | { | |
d0e9fe17 | 951 | struct anon_vma *anon_vma; |
1da177e4 | 952 | struct vm_area_struct *near; |
1da177e4 LT |
953 | |
954 | near = vma->vm_next; | |
955 | if (!near) | |
956 | goto try_prev; | |
957 | ||
d0e9fe17 LT |
958 | anon_vma = reusable_anon_vma(near, vma, near); |
959 | if (anon_vma) | |
960 | return anon_vma; | |
1da177e4 | 961 | try_prev: |
9be34c9d | 962 | near = vma->vm_prev; |
1da177e4 LT |
963 | if (!near) |
964 | goto none; | |
965 | ||
d0e9fe17 LT |
966 | anon_vma = reusable_anon_vma(near, near, vma); |
967 | if (anon_vma) | |
968 | return anon_vma; | |
1da177e4 LT |
969 | none: |
970 | /* | |
971 | * There's no absolute need to look only at touching neighbours: | |
972 | * we could search further afield for "compatible" anon_vmas. | |
973 | * But it would probably just be a waste of time searching, | |
974 | * or lead to too many vmas hanging off the same anon_vma. | |
975 | * We're trying to allow mprotect remerging later on, | |
976 | * not trying to minimize memory used for anon_vmas. | |
977 | */ | |
978 | return NULL; | |
979 | } | |
980 | ||
981 | #ifdef CONFIG_PROC_FS | |
ab50b8ed | 982 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
1da177e4 LT |
983 | struct file *file, long pages) |
984 | { | |
985 | const unsigned long stack_flags | |
986 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); | |
987 | ||
44de9d0c HS |
988 | mm->total_vm += pages; |
989 | ||
1da177e4 LT |
990 | if (file) { |
991 | mm->shared_vm += pages; | |
992 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) | |
993 | mm->exec_vm += pages; | |
994 | } else if (flags & stack_flags) | |
995 | mm->stack_vm += pages; | |
1da177e4 LT |
996 | } |
997 | #endif /* CONFIG_PROC_FS */ | |
998 | ||
40401530 AV |
999 | /* |
1000 | * If a hint addr is less than mmap_min_addr change hint to be as | |
1001 | * low as possible but still greater than mmap_min_addr | |
1002 | */ | |
1003 | static inline unsigned long round_hint_to_min(unsigned long hint) | |
1004 | { | |
1005 | hint &= PAGE_MASK; | |
1006 | if (((void *)hint != NULL) && | |
1007 | (hint < mmap_min_addr)) | |
1008 | return PAGE_ALIGN(mmap_min_addr); | |
1009 | return hint; | |
1010 | } | |
1011 | ||
1da177e4 | 1012 | /* |
27f5de79 | 1013 | * The caller must hold down_write(¤t->mm->mmap_sem). |
1da177e4 LT |
1014 | */ |
1015 | ||
e3fc629d | 1016 | unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, |
1da177e4 LT |
1017 | unsigned long len, unsigned long prot, |
1018 | unsigned long flags, unsigned long pgoff) | |
1019 | { | |
1020 | struct mm_struct * mm = current->mm; | |
1da177e4 | 1021 | struct inode *inode; |
ca16d140 | 1022 | vm_flags_t vm_flags; |
1da177e4 | 1023 | |
1da177e4 LT |
1024 | /* |
1025 | * Does the application expect PROT_READ to imply PROT_EXEC? | |
1026 | * | |
1027 | * (the exception is when the underlying filesystem is noexec | |
1028 | * mounted, in which case we dont add PROT_EXEC.) | |
1029 | */ | |
1030 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) | |
d3ac7f89 | 1031 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
1da177e4 LT |
1032 | prot |= PROT_EXEC; |
1033 | ||
1034 | if (!len) | |
1035 | return -EINVAL; | |
1036 | ||
7cd94146 EP |
1037 | if (!(flags & MAP_FIXED)) |
1038 | addr = round_hint_to_min(addr); | |
1039 | ||
1da177e4 LT |
1040 | /* Careful about overflows.. */ |
1041 | len = PAGE_ALIGN(len); | |
9206de95 | 1042 | if (!len) |
1da177e4 LT |
1043 | return -ENOMEM; |
1044 | ||
1045 | /* offset overflow? */ | |
1046 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
1047 | return -EOVERFLOW; | |
1048 | ||
1049 | /* Too many mappings? */ | |
1050 | if (mm->map_count > sysctl_max_map_count) | |
1051 | return -ENOMEM; | |
1052 | ||
1053 | /* Obtain the address to map to. we verify (or select) it and ensure | |
1054 | * that it represents a valid section of the address space. | |
1055 | */ | |
1056 | addr = get_unmapped_area(file, addr, len, pgoff, flags); | |
1057 | if (addr & ~PAGE_MASK) | |
1058 | return addr; | |
1059 | ||
1060 | /* Do simple checking here so the lower-level routines won't have | |
1061 | * to. we assume access permissions have been handled by the open | |
1062 | * of the memory object, so we don't do any here. | |
1063 | */ | |
1064 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | | |
1065 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
1066 | ||
cdf7b341 | 1067 | if (flags & MAP_LOCKED) |
1da177e4 LT |
1068 | if (!can_do_mlock()) |
1069 | return -EPERM; | |
ba470de4 | 1070 | |
1da177e4 LT |
1071 | /* mlock MCL_FUTURE? */ |
1072 | if (vm_flags & VM_LOCKED) { | |
1073 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
1074 | locked = len >> PAGE_SHIFT; |
1075 | locked += mm->locked_vm; | |
59e99e5b | 1076 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 1077 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
1078 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
1079 | return -EAGAIN; | |
1080 | } | |
1081 | ||
d3ac7f89 | 1082 | inode = file ? file->f_path.dentry->d_inode : NULL; |
1da177e4 LT |
1083 | |
1084 | if (file) { | |
1085 | switch (flags & MAP_TYPE) { | |
1086 | case MAP_SHARED: | |
1087 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) | |
1088 | return -EACCES; | |
1089 | ||
1090 | /* | |
1091 | * Make sure we don't allow writing to an append-only | |
1092 | * file.. | |
1093 | */ | |
1094 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) | |
1095 | return -EACCES; | |
1096 | ||
1097 | /* | |
1098 | * Make sure there are no mandatory locks on the file. | |
1099 | */ | |
1100 | if (locks_verify_locked(inode)) | |
1101 | return -EAGAIN; | |
1102 | ||
1103 | vm_flags |= VM_SHARED | VM_MAYSHARE; | |
1104 | if (!(file->f_mode & FMODE_WRITE)) | |
1105 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); | |
1106 | ||
1107 | /* fall through */ | |
1108 | case MAP_PRIVATE: | |
1109 | if (!(file->f_mode & FMODE_READ)) | |
1110 | return -EACCES; | |
d3ac7f89 | 1111 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
80c5606c LT |
1112 | if (vm_flags & VM_EXEC) |
1113 | return -EPERM; | |
1114 | vm_flags &= ~VM_MAYEXEC; | |
1115 | } | |
80c5606c LT |
1116 | |
1117 | if (!file->f_op || !file->f_op->mmap) | |
1118 | return -ENODEV; | |
1da177e4 LT |
1119 | break; |
1120 | ||
1121 | default: | |
1122 | return -EINVAL; | |
1123 | } | |
1124 | } else { | |
1125 | switch (flags & MAP_TYPE) { | |
1126 | case MAP_SHARED: | |
ce363942 TH |
1127 | /* |
1128 | * Ignore pgoff. | |
1129 | */ | |
1130 | pgoff = 0; | |
1da177e4 LT |
1131 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
1132 | break; | |
1133 | case MAP_PRIVATE: | |
1134 | /* | |
1135 | * Set pgoff according to addr for anon_vma. | |
1136 | */ | |
1137 | pgoff = addr >> PAGE_SHIFT; | |
1138 | break; | |
1139 | default: | |
1140 | return -EINVAL; | |
1141 | } | |
1142 | } | |
1143 | ||
5a6fe125 | 1144 | return mmap_region(file, addr, len, flags, vm_flags, pgoff); |
0165ab44 | 1145 | } |
6be5ceb0 | 1146 | |
66f0dc48 HD |
1147 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1148 | unsigned long, prot, unsigned long, flags, | |
1149 | unsigned long, fd, unsigned long, pgoff) | |
1150 | { | |
1151 | struct file *file = NULL; | |
1152 | unsigned long retval = -EBADF; | |
1153 | ||
1154 | if (!(flags & MAP_ANONYMOUS)) { | |
120a795d | 1155 | audit_mmap_fd(fd, flags); |
66f0dc48 HD |
1156 | if (unlikely(flags & MAP_HUGETLB)) |
1157 | return -EINVAL; | |
1158 | file = fget(fd); | |
1159 | if (!file) | |
1160 | goto out; | |
1161 | } else if (flags & MAP_HUGETLB) { | |
1162 | struct user_struct *user = NULL; | |
1163 | /* | |
1164 | * VM_NORESERVE is used because the reservations will be | |
1165 | * taken when vm_ops->mmap() is called | |
1166 | * A dummy user value is used because we are not locking | |
1167 | * memory so no accounting is necessary | |
1168 | */ | |
40716e29 ST |
1169 | file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len, |
1170 | VM_NORESERVE, &user, | |
1171 | HUGETLB_ANONHUGE_INODE); | |
66f0dc48 HD |
1172 | if (IS_ERR(file)) |
1173 | return PTR_ERR(file); | |
1174 | } | |
1175 | ||
1176 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); | |
1177 | ||
eb36c587 | 1178 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
66f0dc48 HD |
1179 | if (file) |
1180 | fput(file); | |
1181 | out: | |
1182 | return retval; | |
1183 | } | |
1184 | ||
a4679373 CH |
1185 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1186 | struct mmap_arg_struct { | |
1187 | unsigned long addr; | |
1188 | unsigned long len; | |
1189 | unsigned long prot; | |
1190 | unsigned long flags; | |
1191 | unsigned long fd; | |
1192 | unsigned long offset; | |
1193 | }; | |
1194 | ||
1195 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) | |
1196 | { | |
1197 | struct mmap_arg_struct a; | |
1198 | ||
1199 | if (copy_from_user(&a, arg, sizeof(a))) | |
1200 | return -EFAULT; | |
1201 | if (a.offset & ~PAGE_MASK) | |
1202 | return -EINVAL; | |
1203 | ||
1204 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, | |
1205 | a.offset >> PAGE_SHIFT); | |
1206 | } | |
1207 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ | |
1208 | ||
4e950f6f AD |
1209 | /* |
1210 | * Some shared mappigns will want the pages marked read-only | |
1211 | * to track write events. If so, we'll downgrade vm_page_prot | |
1212 | * to the private version (using protection_map[] without the | |
1213 | * VM_SHARED bit). | |
1214 | */ | |
1215 | int vma_wants_writenotify(struct vm_area_struct *vma) | |
1216 | { | |
ca16d140 | 1217 | vm_flags_t vm_flags = vma->vm_flags; |
4e950f6f AD |
1218 | |
1219 | /* If it was private or non-writable, the write bit is already clear */ | |
1220 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) | |
1221 | return 0; | |
1222 | ||
1223 | /* The backer wishes to know when pages are first written to? */ | |
1224 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) | |
1225 | return 1; | |
1226 | ||
1227 | /* The open routine did something to the protections already? */ | |
1228 | if (pgprot_val(vma->vm_page_prot) != | |
3ed75eb8 | 1229 | pgprot_val(vm_get_page_prot(vm_flags))) |
4e950f6f AD |
1230 | return 0; |
1231 | ||
1232 | /* Specialty mapping? */ | |
4b6e1e37 | 1233 | if (vm_flags & VM_PFNMAP) |
4e950f6f AD |
1234 | return 0; |
1235 | ||
1236 | /* Can the mapping track the dirty pages? */ | |
1237 | return vma->vm_file && vma->vm_file->f_mapping && | |
1238 | mapping_cap_account_dirty(vma->vm_file->f_mapping); | |
1239 | } | |
1240 | ||
fc8744ad LT |
1241 | /* |
1242 | * We account for memory if it's a private writeable mapping, | |
5a6fe125 | 1243 | * not hugepages and VM_NORESERVE wasn't set. |
fc8744ad | 1244 | */ |
ca16d140 | 1245 | static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) |
fc8744ad | 1246 | { |
5a6fe125 MG |
1247 | /* |
1248 | * hugetlb has its own accounting separate from the core VM | |
1249 | * VM_HUGETLB may not be set yet so we cannot check for that flag. | |
1250 | */ | |
1251 | if (file && is_file_hugepages(file)) | |
1252 | return 0; | |
1253 | ||
fc8744ad LT |
1254 | return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; |
1255 | } | |
1256 | ||
0165ab44 MS |
1257 | unsigned long mmap_region(struct file *file, unsigned long addr, |
1258 | unsigned long len, unsigned long flags, | |
ca16d140 | 1259 | vm_flags_t vm_flags, unsigned long pgoff) |
0165ab44 MS |
1260 | { |
1261 | struct mm_struct *mm = current->mm; | |
1262 | struct vm_area_struct *vma, *prev; | |
1263 | int correct_wcount = 0; | |
1264 | int error; | |
1265 | struct rb_node **rb_link, *rb_parent; | |
1266 | unsigned long charged = 0; | |
1267 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; | |
1268 | ||
1da177e4 LT |
1269 | /* Clear old maps */ |
1270 | error = -ENOMEM; | |
1271 | munmap_back: | |
6597d783 | 1272 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
1273 | if (do_munmap(mm, addr, len)) |
1274 | return -ENOMEM; | |
1275 | goto munmap_back; | |
1276 | } | |
1277 | ||
1278 | /* Check against address space limit. */ | |
119f657c | 1279 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
1280 | return -ENOMEM; |
1281 | ||
fc8744ad LT |
1282 | /* |
1283 | * Set 'VM_NORESERVE' if we should not account for the | |
5a6fe125 | 1284 | * memory use of this mapping. |
fc8744ad | 1285 | */ |
5a6fe125 MG |
1286 | if ((flags & MAP_NORESERVE)) { |
1287 | /* We honor MAP_NORESERVE if allowed to overcommit */ | |
1288 | if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
1289 | vm_flags |= VM_NORESERVE; | |
1290 | ||
1291 | /* hugetlb applies strict overcommit unless MAP_NORESERVE */ | |
1292 | if (file && is_file_hugepages(file)) | |
1293 | vm_flags |= VM_NORESERVE; | |
1294 | } | |
cdfd4325 | 1295 | |
fc8744ad LT |
1296 | /* |
1297 | * Private writable mapping: check memory availability | |
1298 | */ | |
5a6fe125 | 1299 | if (accountable_mapping(file, vm_flags)) { |
fc8744ad | 1300 | charged = len >> PAGE_SHIFT; |
191c5424 | 1301 | if (security_vm_enough_memory_mm(mm, charged)) |
fc8744ad LT |
1302 | return -ENOMEM; |
1303 | vm_flags |= VM_ACCOUNT; | |
1da177e4 LT |
1304 | } |
1305 | ||
1306 | /* | |
de33c8db | 1307 | * Can we just expand an old mapping? |
1da177e4 | 1308 | */ |
de33c8db LT |
1309 | vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); |
1310 | if (vma) | |
1311 | goto out; | |
1da177e4 LT |
1312 | |
1313 | /* | |
1314 | * Determine the object being mapped and call the appropriate | |
1315 | * specific mapper. the address has already been validated, but | |
1316 | * not unmapped, but the maps are removed from the list. | |
1317 | */ | |
c5e3b83e | 1318 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
1319 | if (!vma) { |
1320 | error = -ENOMEM; | |
1321 | goto unacct_error; | |
1322 | } | |
1da177e4 LT |
1323 | |
1324 | vma->vm_mm = mm; | |
1325 | vma->vm_start = addr; | |
1326 | vma->vm_end = addr + len; | |
1327 | vma->vm_flags = vm_flags; | |
3ed75eb8 | 1328 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
1da177e4 | 1329 | vma->vm_pgoff = pgoff; |
5beb4930 | 1330 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 | 1331 | |
ce8fea7a HD |
1332 | error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */ |
1333 | ||
1da177e4 | 1334 | if (file) { |
1da177e4 LT |
1335 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
1336 | goto free_vma; | |
1337 | if (vm_flags & VM_DENYWRITE) { | |
1338 | error = deny_write_access(file); | |
1339 | if (error) | |
1340 | goto free_vma; | |
1341 | correct_wcount = 1; | |
1342 | } | |
cb0942b8 | 1343 | vma->vm_file = get_file(file); |
1da177e4 LT |
1344 | error = file->f_op->mmap(file, vma); |
1345 | if (error) | |
1346 | goto unmap_and_free_vma; | |
f8dbf0a7 HS |
1347 | |
1348 | /* Can addr have changed?? | |
1349 | * | |
1350 | * Answer: Yes, several device drivers can do it in their | |
1351 | * f_op->mmap method. -DaveM | |
1352 | */ | |
1353 | addr = vma->vm_start; | |
1354 | pgoff = vma->vm_pgoff; | |
1355 | vm_flags = vma->vm_flags; | |
1da177e4 | 1356 | } else if (vm_flags & VM_SHARED) { |
835ee797 AV |
1357 | if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))) |
1358 | goto free_vma; | |
1da177e4 LT |
1359 | error = shmem_zero_setup(vma); |
1360 | if (error) | |
1361 | goto free_vma; | |
1362 | } | |
1363 | ||
c9d0bf24 MD |
1364 | if (vma_wants_writenotify(vma)) { |
1365 | pgprot_t pprot = vma->vm_page_prot; | |
1366 | ||
1367 | /* Can vma->vm_page_prot have changed?? | |
1368 | * | |
1369 | * Answer: Yes, drivers may have changed it in their | |
1370 | * f_op->mmap method. | |
1371 | * | |
1372 | * Ensures that vmas marked as uncached stay that way. | |
1373 | */ | |
1ddd439e | 1374 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
c9d0bf24 MD |
1375 | if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) |
1376 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
1377 | } | |
d08b3851 | 1378 | |
de33c8db LT |
1379 | vma_link(mm, vma, prev, rb_link, rb_parent); |
1380 | file = vma->vm_file; | |
4d3d5b41 ON |
1381 | |
1382 | /* Once vma denies write, undo our temporary denial count */ | |
1383 | if (correct_wcount) | |
1384 | atomic_inc(&inode->i_writecount); | |
1385 | out: | |
cdd6c482 | 1386 | perf_event_mmap(vma); |
0a4a9391 | 1387 | |
ab50b8ed | 1388 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
1da177e4 | 1389 | if (vm_flags & VM_LOCKED) { |
06f9d8c2 KM |
1390 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
1391 | mm->locked_vm += (len >> PAGE_SHIFT); | |
ba470de4 | 1392 | } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
54cb8821 | 1393 | make_pages_present(addr, addr + len); |
2b144498 | 1394 | |
c7a3a88c ON |
1395 | if (file) |
1396 | uprobe_mmap(vma); | |
2b144498 | 1397 | |
1da177e4 LT |
1398 | return addr; |
1399 | ||
1400 | unmap_and_free_vma: | |
1401 | if (correct_wcount) | |
1402 | atomic_inc(&inode->i_writecount); | |
1403 | vma->vm_file = NULL; | |
1404 | fput(file); | |
1405 | ||
1406 | /* Undo any partial mapping done by a device driver. */ | |
e0da382c HD |
1407 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
1408 | charged = 0; | |
1da177e4 LT |
1409 | free_vma: |
1410 | kmem_cache_free(vm_area_cachep, vma); | |
1411 | unacct_error: | |
1412 | if (charged) | |
1413 | vm_unacct_memory(charged); | |
1414 | return error; | |
1415 | } | |
1416 | ||
1da177e4 LT |
1417 | /* Get an address range which is currently unmapped. |
1418 | * For shmat() with addr=0. | |
1419 | * | |
1420 | * Ugly calling convention alert: | |
1421 | * Return value with the low bits set means error value, | |
1422 | * ie | |
1423 | * if (ret & ~PAGE_MASK) | |
1424 | * error = ret; | |
1425 | * | |
1426 | * This function "knows" that -ENOMEM has the bits set. | |
1427 | */ | |
1428 | #ifndef HAVE_ARCH_UNMAPPED_AREA | |
1429 | unsigned long | |
1430 | arch_get_unmapped_area(struct file *filp, unsigned long addr, | |
1431 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1432 | { | |
1433 | struct mm_struct *mm = current->mm; | |
1434 | struct vm_area_struct *vma; | |
1435 | unsigned long start_addr; | |
1436 | ||
1437 | if (len > TASK_SIZE) | |
1438 | return -ENOMEM; | |
1439 | ||
06abdfb4 BH |
1440 | if (flags & MAP_FIXED) |
1441 | return addr; | |
1442 | ||
1da177e4 LT |
1443 | if (addr) { |
1444 | addr = PAGE_ALIGN(addr); | |
1445 | vma = find_vma(mm, addr); | |
1446 | if (TASK_SIZE - len >= addr && | |
1447 | (!vma || addr + len <= vma->vm_start)) | |
1448 | return addr; | |
1449 | } | |
1363c3cd WW |
1450 | if (len > mm->cached_hole_size) { |
1451 | start_addr = addr = mm->free_area_cache; | |
1452 | } else { | |
1453 | start_addr = addr = TASK_UNMAPPED_BASE; | |
1454 | mm->cached_hole_size = 0; | |
1455 | } | |
1da177e4 LT |
1456 | |
1457 | full_search: | |
1458 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { | |
1459 | /* At this point: (!vma || addr < vma->vm_end). */ | |
1460 | if (TASK_SIZE - len < addr) { | |
1461 | /* | |
1462 | * Start a new search - just in case we missed | |
1463 | * some holes. | |
1464 | */ | |
1465 | if (start_addr != TASK_UNMAPPED_BASE) { | |
1363c3cd WW |
1466 | addr = TASK_UNMAPPED_BASE; |
1467 | start_addr = addr; | |
1468 | mm->cached_hole_size = 0; | |
1da177e4 LT |
1469 | goto full_search; |
1470 | } | |
1471 | return -ENOMEM; | |
1472 | } | |
1473 | if (!vma || addr + len <= vma->vm_start) { | |
1474 | /* | |
1475 | * Remember the place where we stopped the search: | |
1476 | */ | |
1477 | mm->free_area_cache = addr + len; | |
1478 | return addr; | |
1479 | } | |
1363c3cd WW |
1480 | if (addr + mm->cached_hole_size < vma->vm_start) |
1481 | mm->cached_hole_size = vma->vm_start - addr; | |
1da177e4 LT |
1482 | addr = vma->vm_end; |
1483 | } | |
1484 | } | |
1485 | #endif | |
1486 | ||
1363c3cd | 1487 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1488 | { |
1489 | /* | |
1490 | * Is this a new hole at the lowest possible address? | |
1491 | */ | |
f44d2198 | 1492 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) |
1363c3cd | 1493 | mm->free_area_cache = addr; |
1da177e4 LT |
1494 | } |
1495 | ||
1496 | /* | |
1497 | * This mmap-allocator allocates new areas top-down from below the | |
1498 | * stack's low limit (the base): | |
1499 | */ | |
1500 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN | |
1501 | unsigned long | |
1502 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, | |
1503 | const unsigned long len, const unsigned long pgoff, | |
1504 | const unsigned long flags) | |
1505 | { | |
1506 | struct vm_area_struct *vma; | |
1507 | struct mm_struct *mm = current->mm; | |
b716ad95 | 1508 | unsigned long addr = addr0, start_addr; |
1da177e4 LT |
1509 | |
1510 | /* requested length too big for entire address space */ | |
1511 | if (len > TASK_SIZE) | |
1512 | return -ENOMEM; | |
1513 | ||
06abdfb4 BH |
1514 | if (flags & MAP_FIXED) |
1515 | return addr; | |
1516 | ||
1da177e4 LT |
1517 | /* requesting a specific address */ |
1518 | if (addr) { | |
1519 | addr = PAGE_ALIGN(addr); | |
1520 | vma = find_vma(mm, addr); | |
1521 | if (TASK_SIZE - len >= addr && | |
1522 | (!vma || addr + len <= vma->vm_start)) | |
1523 | return addr; | |
1524 | } | |
1525 | ||
1363c3cd WW |
1526 | /* check if free_area_cache is useful for us */ |
1527 | if (len <= mm->cached_hole_size) { | |
1528 | mm->cached_hole_size = 0; | |
1529 | mm->free_area_cache = mm->mmap_base; | |
1530 | } | |
1531 | ||
b716ad95 | 1532 | try_again: |
1da177e4 | 1533 | /* either no address requested or can't fit in requested address hole */ |
b716ad95 | 1534 | start_addr = addr = mm->free_area_cache; |
73219d17 | 1535 | |
b716ad95 XG |
1536 | if (addr < len) |
1537 | goto fail; | |
1da177e4 | 1538 | |
b716ad95 | 1539 | addr -= len; |
1da177e4 LT |
1540 | do { |
1541 | /* | |
1542 | * Lookup failure means no vma is above this address, | |
1543 | * else if new region fits below vma->vm_start, | |
1544 | * return with success: | |
1545 | */ | |
1546 | vma = find_vma(mm, addr); | |
1547 | if (!vma || addr+len <= vma->vm_start) | |
1548 | /* remember the address as a hint for next time */ | |
1549 | return (mm->free_area_cache = addr); | |
1550 | ||
1363c3cd WW |
1551 | /* remember the largest hole we saw so far */ |
1552 | if (addr + mm->cached_hole_size < vma->vm_start) | |
1553 | mm->cached_hole_size = vma->vm_start - addr; | |
1554 | ||
1da177e4 LT |
1555 | /* try just below the current vma->vm_start */ |
1556 | addr = vma->vm_start-len; | |
49a43876 | 1557 | } while (len < vma->vm_start); |
1da177e4 | 1558 | |
b716ad95 XG |
1559 | fail: |
1560 | /* | |
1561 | * if hint left us with no space for the requested | |
1562 | * mapping then try again: | |
1563 | * | |
1564 | * Note: this is different with the case of bottomup | |
1565 | * which does the fully line-search, but we use find_vma | |
1566 | * here that causes some holes skipped. | |
1567 | */ | |
1568 | if (start_addr != mm->mmap_base) { | |
1569 | mm->free_area_cache = mm->mmap_base; | |
1570 | mm->cached_hole_size = 0; | |
1571 | goto try_again; | |
1572 | } | |
1573 | ||
1da177e4 LT |
1574 | /* |
1575 | * A failed mmap() very likely causes application failure, | |
1576 | * so fall back to the bottom-up function here. This scenario | |
1577 | * can happen with large stack limits and large mmap() | |
1578 | * allocations. | |
1579 | */ | |
1363c3cd WW |
1580 | mm->cached_hole_size = ~0UL; |
1581 | mm->free_area_cache = TASK_UNMAPPED_BASE; | |
1da177e4 LT |
1582 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
1583 | /* | |
1584 | * Restore the topdown base: | |
1585 | */ | |
1586 | mm->free_area_cache = mm->mmap_base; | |
1363c3cd | 1587 | mm->cached_hole_size = ~0UL; |
1da177e4 LT |
1588 | |
1589 | return addr; | |
1590 | } | |
1591 | #endif | |
1592 | ||
1363c3cd | 1593 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1594 | { |
1595 | /* | |
1596 | * Is this a new hole at the highest possible address? | |
1597 | */ | |
1363c3cd WW |
1598 | if (addr > mm->free_area_cache) |
1599 | mm->free_area_cache = addr; | |
1da177e4 LT |
1600 | |
1601 | /* dont allow allocations above current base */ | |
1363c3cd WW |
1602 | if (mm->free_area_cache > mm->mmap_base) |
1603 | mm->free_area_cache = mm->mmap_base; | |
1da177e4 LT |
1604 | } |
1605 | ||
1606 | unsigned long | |
1607 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, | |
1608 | unsigned long pgoff, unsigned long flags) | |
1609 | { | |
06abdfb4 BH |
1610 | unsigned long (*get_area)(struct file *, unsigned long, |
1611 | unsigned long, unsigned long, unsigned long); | |
1612 | ||
9206de95 AV |
1613 | unsigned long error = arch_mmap_check(addr, len, flags); |
1614 | if (error) | |
1615 | return error; | |
1616 | ||
1617 | /* Careful about overflows.. */ | |
1618 | if (len > TASK_SIZE) | |
1619 | return -ENOMEM; | |
1620 | ||
06abdfb4 BH |
1621 | get_area = current->mm->get_unmapped_area; |
1622 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1623 | get_area = file->f_op->get_unmapped_area; | |
1624 | addr = get_area(file, addr, len, pgoff, flags); | |
1625 | if (IS_ERR_VALUE(addr)) | |
1626 | return addr; | |
1da177e4 | 1627 | |
07ab67c8 LT |
1628 | if (addr > TASK_SIZE - len) |
1629 | return -ENOMEM; | |
1630 | if (addr & ~PAGE_MASK) | |
1631 | return -EINVAL; | |
06abdfb4 | 1632 | |
9ac4ed4b AV |
1633 | addr = arch_rebalance_pgtables(addr, len); |
1634 | error = security_mmap_addr(addr); | |
1635 | return error ? error : addr; | |
1da177e4 LT |
1636 | } |
1637 | ||
1638 | EXPORT_SYMBOL(get_unmapped_area); | |
1639 | ||
1640 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ | |
48aae425 | 1641 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1642 | { |
1643 | struct vm_area_struct *vma = NULL; | |
1644 | ||
841e31e5 RM |
1645 | if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */ |
1646 | return NULL; | |
1647 | ||
1648 | /* Check the cache first. */ | |
1649 | /* (Cache hit rate is typically around 35%.) */ | |
1650 | vma = mm->mmap_cache; | |
1651 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { | |
1652 | struct rb_node *rb_node; | |
1653 | ||
1654 | rb_node = mm->mm_rb.rb_node; | |
1655 | vma = NULL; | |
1656 | ||
1657 | while (rb_node) { | |
1658 | struct vm_area_struct *vma_tmp; | |
1659 | ||
1660 | vma_tmp = rb_entry(rb_node, | |
1661 | struct vm_area_struct, vm_rb); | |
1662 | ||
1663 | if (vma_tmp->vm_end > addr) { | |
1664 | vma = vma_tmp; | |
1665 | if (vma_tmp->vm_start <= addr) | |
1666 | break; | |
1667 | rb_node = rb_node->rb_left; | |
1668 | } else | |
1669 | rb_node = rb_node->rb_right; | |
1da177e4 | 1670 | } |
841e31e5 RM |
1671 | if (vma) |
1672 | mm->mmap_cache = vma; | |
1da177e4 LT |
1673 | } |
1674 | return vma; | |
1675 | } | |
1676 | ||
1677 | EXPORT_SYMBOL(find_vma); | |
1678 | ||
6bd4837d KM |
1679 | /* |
1680 | * Same as find_vma, but also return a pointer to the previous VMA in *pprev. | |
6bd4837d | 1681 | */ |
1da177e4 LT |
1682 | struct vm_area_struct * |
1683 | find_vma_prev(struct mm_struct *mm, unsigned long addr, | |
1684 | struct vm_area_struct **pprev) | |
1685 | { | |
6bd4837d | 1686 | struct vm_area_struct *vma; |
1da177e4 | 1687 | |
6bd4837d | 1688 | vma = find_vma(mm, addr); |
83cd904d MP |
1689 | if (vma) { |
1690 | *pprev = vma->vm_prev; | |
1691 | } else { | |
1692 | struct rb_node *rb_node = mm->mm_rb.rb_node; | |
1693 | *pprev = NULL; | |
1694 | while (rb_node) { | |
1695 | *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); | |
1696 | rb_node = rb_node->rb_right; | |
1697 | } | |
1698 | } | |
6bd4837d | 1699 | return vma; |
1da177e4 LT |
1700 | } |
1701 | ||
1702 | /* | |
1703 | * Verify that the stack growth is acceptable and | |
1704 | * update accounting. This is shared with both the | |
1705 | * grow-up and grow-down cases. | |
1706 | */ | |
48aae425 | 1707 | static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) |
1da177e4 LT |
1708 | { |
1709 | struct mm_struct *mm = vma->vm_mm; | |
1710 | struct rlimit *rlim = current->signal->rlim; | |
0d59a01b | 1711 | unsigned long new_start; |
1da177e4 LT |
1712 | |
1713 | /* address space limit tests */ | |
119f657c | 1714 | if (!may_expand_vm(mm, grow)) |
1da177e4 LT |
1715 | return -ENOMEM; |
1716 | ||
1717 | /* Stack limit test */ | |
59e99e5b | 1718 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) |
1da177e4 LT |
1719 | return -ENOMEM; |
1720 | ||
1721 | /* mlock limit tests */ | |
1722 | if (vma->vm_flags & VM_LOCKED) { | |
1723 | unsigned long locked; | |
1724 | unsigned long limit; | |
1725 | locked = mm->locked_vm + grow; | |
59e99e5b JS |
1726 | limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); |
1727 | limit >>= PAGE_SHIFT; | |
1da177e4 LT |
1728 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
1729 | return -ENOMEM; | |
1730 | } | |
1731 | ||
0d59a01b AL |
1732 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
1733 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : | |
1734 | vma->vm_end - size; | |
1735 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) | |
1736 | return -EFAULT; | |
1737 | ||
1da177e4 LT |
1738 | /* |
1739 | * Overcommit.. This must be the final test, as it will | |
1740 | * update security statistics. | |
1741 | */ | |
05fa199d | 1742 | if (security_vm_enough_memory_mm(mm, grow)) |
1da177e4 LT |
1743 | return -ENOMEM; |
1744 | ||
1745 | /* Ok, everything looks good - let it rip */ | |
1da177e4 LT |
1746 | if (vma->vm_flags & VM_LOCKED) |
1747 | mm->locked_vm += grow; | |
ab50b8ed | 1748 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
1da177e4 LT |
1749 | return 0; |
1750 | } | |
1751 | ||
46dea3d0 | 1752 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
1da177e4 | 1753 | /* |
46dea3d0 HD |
1754 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
1755 | * vma is the last one with address > vma->vm_end. Have to extend vma. | |
1da177e4 | 1756 | */ |
46dea3d0 | 1757 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
1da177e4 LT |
1758 | { |
1759 | int error; | |
1760 | ||
1761 | if (!(vma->vm_flags & VM_GROWSUP)) | |
1762 | return -EFAULT; | |
1763 | ||
1764 | /* | |
1765 | * We must make sure the anon_vma is allocated | |
1766 | * so that the anon_vma locking is not a noop. | |
1767 | */ | |
1768 | if (unlikely(anon_vma_prepare(vma))) | |
1769 | return -ENOMEM; | |
bb4a340e | 1770 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1771 | |
1772 | /* | |
1773 | * vma->vm_start/vm_end cannot change under us because the caller | |
1774 | * is required to hold the mmap_sem in read mode. We need the | |
1775 | * anon_vma lock to serialize against concurrent expand_stacks. | |
06b32f3a | 1776 | * Also guard against wrapping around to address 0. |
1da177e4 | 1777 | */ |
06b32f3a HD |
1778 | if (address < PAGE_ALIGN(address+4)) |
1779 | address = PAGE_ALIGN(address+4); | |
1780 | else { | |
bb4a340e | 1781 | vma_unlock_anon_vma(vma); |
06b32f3a HD |
1782 | return -ENOMEM; |
1783 | } | |
1da177e4 LT |
1784 | error = 0; |
1785 | ||
1786 | /* Somebody else might have raced and expanded it already */ | |
1787 | if (address > vma->vm_end) { | |
1788 | unsigned long size, grow; | |
1789 | ||
1790 | size = address - vma->vm_start; | |
1791 | grow = (address - vma->vm_end) >> PAGE_SHIFT; | |
1792 | ||
42c36f63 HD |
1793 | error = -ENOMEM; |
1794 | if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { | |
1795 | error = acct_stack_growth(vma, size, grow); | |
1796 | if (!error) { | |
bf181b9f | 1797 | anon_vma_interval_tree_pre_update_vma(vma); |
42c36f63 | 1798 | vma->vm_end = address; |
bf181b9f | 1799 | anon_vma_interval_tree_post_update_vma(vma); |
42c36f63 HD |
1800 | perf_event_mmap(vma); |
1801 | } | |
3af9e859 | 1802 | } |
1da177e4 | 1803 | } |
bb4a340e | 1804 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1805 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 1806 | validate_mm(vma->vm_mm); |
1da177e4 LT |
1807 | return error; |
1808 | } | |
46dea3d0 HD |
1809 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
1810 | ||
1da177e4 LT |
1811 | /* |
1812 | * vma is the first one with address < vma->vm_start. Have to extend vma. | |
1813 | */ | |
d05f3169 | 1814 | int expand_downwards(struct vm_area_struct *vma, |
b6a2fea3 | 1815 | unsigned long address) |
1da177e4 LT |
1816 | { |
1817 | int error; | |
1818 | ||
1819 | /* | |
1820 | * We must make sure the anon_vma is allocated | |
1821 | * so that the anon_vma locking is not a noop. | |
1822 | */ | |
1823 | if (unlikely(anon_vma_prepare(vma))) | |
1824 | return -ENOMEM; | |
8869477a EP |
1825 | |
1826 | address &= PAGE_MASK; | |
e5467859 | 1827 | error = security_mmap_addr(address); |
8869477a EP |
1828 | if (error) |
1829 | return error; | |
1830 | ||
bb4a340e | 1831 | vma_lock_anon_vma(vma); |
1da177e4 LT |
1832 | |
1833 | /* | |
1834 | * vma->vm_start/vm_end cannot change under us because the caller | |
1835 | * is required to hold the mmap_sem in read mode. We need the | |
1836 | * anon_vma lock to serialize against concurrent expand_stacks. | |
1837 | */ | |
1da177e4 LT |
1838 | |
1839 | /* Somebody else might have raced and expanded it already */ | |
1840 | if (address < vma->vm_start) { | |
1841 | unsigned long size, grow; | |
1842 | ||
1843 | size = vma->vm_end - address; | |
1844 | grow = (vma->vm_start - address) >> PAGE_SHIFT; | |
1845 | ||
a626ca6a LT |
1846 | error = -ENOMEM; |
1847 | if (grow <= vma->vm_pgoff) { | |
1848 | error = acct_stack_growth(vma, size, grow); | |
1849 | if (!error) { | |
bf181b9f | 1850 | anon_vma_interval_tree_pre_update_vma(vma); |
a626ca6a LT |
1851 | vma->vm_start = address; |
1852 | vma->vm_pgoff -= grow; | |
bf181b9f | 1853 | anon_vma_interval_tree_post_update_vma(vma); |
a626ca6a LT |
1854 | perf_event_mmap(vma); |
1855 | } | |
1da177e4 LT |
1856 | } |
1857 | } | |
bb4a340e | 1858 | vma_unlock_anon_vma(vma); |
b15d00b6 | 1859 | khugepaged_enter_vma_merge(vma); |
ed8ea815 | 1860 | validate_mm(vma->vm_mm); |
1da177e4 LT |
1861 | return error; |
1862 | } | |
1863 | ||
b6a2fea3 OW |
1864 | #ifdef CONFIG_STACK_GROWSUP |
1865 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1866 | { | |
1867 | return expand_upwards(vma, address); | |
1868 | } | |
1869 | ||
1870 | struct vm_area_struct * | |
1871 | find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1872 | { | |
1873 | struct vm_area_struct *vma, *prev; | |
1874 | ||
1875 | addr &= PAGE_MASK; | |
1876 | vma = find_vma_prev(mm, addr, &prev); | |
1877 | if (vma && (vma->vm_start <= addr)) | |
1878 | return vma; | |
1c127185 | 1879 | if (!prev || expand_stack(prev, addr)) |
b6a2fea3 | 1880 | return NULL; |
ba470de4 | 1881 | if (prev->vm_flags & VM_LOCKED) { |
c58267c3 | 1882 | mlock_vma_pages_range(prev, addr, prev->vm_end); |
ba470de4 | 1883 | } |
b6a2fea3 OW |
1884 | return prev; |
1885 | } | |
1886 | #else | |
1887 | int expand_stack(struct vm_area_struct *vma, unsigned long address) | |
1888 | { | |
1889 | return expand_downwards(vma, address); | |
1890 | } | |
1891 | ||
1da177e4 LT |
1892 | struct vm_area_struct * |
1893 | find_extend_vma(struct mm_struct * mm, unsigned long addr) | |
1894 | { | |
1895 | struct vm_area_struct * vma; | |
1896 | unsigned long start; | |
1897 | ||
1898 | addr &= PAGE_MASK; | |
1899 | vma = find_vma(mm,addr); | |
1900 | if (!vma) | |
1901 | return NULL; | |
1902 | if (vma->vm_start <= addr) | |
1903 | return vma; | |
1904 | if (!(vma->vm_flags & VM_GROWSDOWN)) | |
1905 | return NULL; | |
1906 | start = vma->vm_start; | |
1907 | if (expand_stack(vma, addr)) | |
1908 | return NULL; | |
ba470de4 | 1909 | if (vma->vm_flags & VM_LOCKED) { |
c58267c3 | 1910 | mlock_vma_pages_range(vma, addr, start); |
ba470de4 | 1911 | } |
1da177e4 LT |
1912 | return vma; |
1913 | } | |
1914 | #endif | |
1915 | ||
1da177e4 | 1916 | /* |
2c0b3814 | 1917 | * Ok - we have the memory areas we should free on the vma list, |
1da177e4 | 1918 | * so release them, and do the vma updates. |
2c0b3814 HD |
1919 | * |
1920 | * Called with the mm semaphore held. | |
1da177e4 | 1921 | */ |
2c0b3814 | 1922 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 1923 | { |
4f74d2c8 LT |
1924 | unsigned long nr_accounted = 0; |
1925 | ||
365e9c87 HD |
1926 | /* Update high watermark before we lower total_vm */ |
1927 | update_hiwater_vm(mm); | |
1da177e4 | 1928 | do { |
2c0b3814 HD |
1929 | long nrpages = vma_pages(vma); |
1930 | ||
4f74d2c8 LT |
1931 | if (vma->vm_flags & VM_ACCOUNT) |
1932 | nr_accounted += nrpages; | |
2c0b3814 | 1933 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
a8fb5618 | 1934 | vma = remove_vma(vma); |
146425a3 | 1935 | } while (vma); |
4f74d2c8 | 1936 | vm_unacct_memory(nr_accounted); |
1da177e4 LT |
1937 | validate_mm(mm); |
1938 | } | |
1939 | ||
1940 | /* | |
1941 | * Get rid of page table information in the indicated region. | |
1942 | * | |
f10df686 | 1943 | * Called with the mm semaphore held. |
1da177e4 LT |
1944 | */ |
1945 | static void unmap_region(struct mm_struct *mm, | |
e0da382c HD |
1946 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
1947 | unsigned long start, unsigned long end) | |
1da177e4 | 1948 | { |
e0da382c | 1949 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
d16dfc55 | 1950 | struct mmu_gather tlb; |
1da177e4 LT |
1951 | |
1952 | lru_add_drain(); | |
d16dfc55 | 1953 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1954 | update_hiwater_rss(mm); |
4f74d2c8 | 1955 | unmap_vmas(&tlb, vma, start, end); |
d16dfc55 PZ |
1956 | free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, |
1957 | next ? next->vm_start : 0); | |
1958 | tlb_finish_mmu(&tlb, start, end); | |
1da177e4 LT |
1959 | } |
1960 | ||
1961 | /* | |
1962 | * Create a list of vma's touched by the unmap, removing them from the mm's | |
1963 | * vma list as we go.. | |
1964 | */ | |
1965 | static void | |
1966 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, | |
1967 | struct vm_area_struct *prev, unsigned long end) | |
1968 | { | |
1969 | struct vm_area_struct **insertion_point; | |
1970 | struct vm_area_struct *tail_vma = NULL; | |
1363c3cd | 1971 | unsigned long addr; |
1da177e4 LT |
1972 | |
1973 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); | |
297c5eee | 1974 | vma->vm_prev = NULL; |
1da177e4 LT |
1975 | do { |
1976 | rb_erase(&vma->vm_rb, &mm->mm_rb); | |
1977 | mm->map_count--; | |
1978 | tail_vma = vma; | |
1979 | vma = vma->vm_next; | |
1980 | } while (vma && vma->vm_start < end); | |
1981 | *insertion_point = vma; | |
297c5eee LT |
1982 | if (vma) |
1983 | vma->vm_prev = prev; | |
1da177e4 | 1984 | tail_vma->vm_next = NULL; |
1363c3cd WW |
1985 | if (mm->unmap_area == arch_unmap_area) |
1986 | addr = prev ? prev->vm_end : mm->mmap_base; | |
1987 | else | |
1988 | addr = vma ? vma->vm_start : mm->mmap_base; | |
1989 | mm->unmap_area(mm, addr); | |
1da177e4 LT |
1990 | mm->mmap_cache = NULL; /* Kill the cache. */ |
1991 | } | |
1992 | ||
1993 | /* | |
659ace58 KM |
1994 | * __split_vma() bypasses sysctl_max_map_count checking. We use this on the |
1995 | * munmap path where it doesn't make sense to fail. | |
1da177e4 | 1996 | */ |
659ace58 | 1997 | static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
1da177e4 LT |
1998 | unsigned long addr, int new_below) |
1999 | { | |
2000 | struct mempolicy *pol; | |
2001 | struct vm_area_struct *new; | |
5beb4930 | 2002 | int err = -ENOMEM; |
1da177e4 | 2003 | |
a5516438 AK |
2004 | if (is_vm_hugetlb_page(vma) && (addr & |
2005 | ~(huge_page_mask(hstate_vma(vma))))) | |
1da177e4 LT |
2006 | return -EINVAL; |
2007 | ||
e94b1766 | 2008 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 | 2009 | if (!new) |
5beb4930 | 2010 | goto out_err; |
1da177e4 LT |
2011 | |
2012 | /* most fields are the same, copy all, and then fixup */ | |
2013 | *new = *vma; | |
2014 | ||
5beb4930 RR |
2015 | INIT_LIST_HEAD(&new->anon_vma_chain); |
2016 | ||
1da177e4 LT |
2017 | if (new_below) |
2018 | new->vm_end = addr; | |
2019 | else { | |
2020 | new->vm_start = addr; | |
2021 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); | |
2022 | } | |
2023 | ||
846a16bf | 2024 | pol = mpol_dup(vma_policy(vma)); |
1da177e4 | 2025 | if (IS_ERR(pol)) { |
5beb4930 RR |
2026 | err = PTR_ERR(pol); |
2027 | goto out_free_vma; | |
1da177e4 LT |
2028 | } |
2029 | vma_set_policy(new, pol); | |
2030 | ||
5beb4930 RR |
2031 | if (anon_vma_clone(new, vma)) |
2032 | goto out_free_mpol; | |
2033 | ||
e9714acf | 2034 | if (new->vm_file) |
1da177e4 LT |
2035 | get_file(new->vm_file); |
2036 | ||
2037 | if (new->vm_ops && new->vm_ops->open) | |
2038 | new->vm_ops->open(new); | |
2039 | ||
2040 | if (new_below) | |
5beb4930 | 2041 | err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
1da177e4 LT |
2042 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
2043 | else | |
5beb4930 | 2044 | err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
1da177e4 | 2045 | |
5beb4930 RR |
2046 | /* Success. */ |
2047 | if (!err) | |
2048 | return 0; | |
2049 | ||
2050 | /* Clean everything up if vma_adjust failed. */ | |
58927533 RR |
2051 | if (new->vm_ops && new->vm_ops->close) |
2052 | new->vm_ops->close(new); | |
e9714acf | 2053 | if (new->vm_file) |
5beb4930 | 2054 | fput(new->vm_file); |
2aeadc30 | 2055 | unlink_anon_vmas(new); |
5beb4930 RR |
2056 | out_free_mpol: |
2057 | mpol_put(pol); | |
2058 | out_free_vma: | |
2059 | kmem_cache_free(vm_area_cachep, new); | |
2060 | out_err: | |
2061 | return err; | |
1da177e4 LT |
2062 | } |
2063 | ||
659ace58 KM |
2064 | /* |
2065 | * Split a vma into two pieces at address 'addr', a new vma is allocated | |
2066 | * either for the first part or the tail. | |
2067 | */ | |
2068 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, | |
2069 | unsigned long addr, int new_below) | |
2070 | { | |
2071 | if (mm->map_count >= sysctl_max_map_count) | |
2072 | return -ENOMEM; | |
2073 | ||
2074 | return __split_vma(mm, vma, addr, new_below); | |
2075 | } | |
2076 | ||
1da177e4 LT |
2077 | /* Munmap is split into 2 main parts -- this part which finds |
2078 | * what needs doing, and the areas themselves, which do the | |
2079 | * work. This now handles partial unmappings. | |
2080 | * Jeremy Fitzhardinge <jeremy@goop.org> | |
2081 | */ | |
2082 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) | |
2083 | { | |
2084 | unsigned long end; | |
146425a3 | 2085 | struct vm_area_struct *vma, *prev, *last; |
1da177e4 LT |
2086 | |
2087 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) | |
2088 | return -EINVAL; | |
2089 | ||
2090 | if ((len = PAGE_ALIGN(len)) == 0) | |
2091 | return -EINVAL; | |
2092 | ||
2093 | /* Find the first overlapping VMA */ | |
9be34c9d | 2094 | vma = find_vma(mm, start); |
146425a3 | 2095 | if (!vma) |
1da177e4 | 2096 | return 0; |
9be34c9d | 2097 | prev = vma->vm_prev; |
146425a3 | 2098 | /* we have start < vma->vm_end */ |
1da177e4 LT |
2099 | |
2100 | /* if it doesn't overlap, we have nothing.. */ | |
2101 | end = start + len; | |
146425a3 | 2102 | if (vma->vm_start >= end) |
1da177e4 LT |
2103 | return 0; |
2104 | ||
2105 | /* | |
2106 | * If we need to split any vma, do it now to save pain later. | |
2107 | * | |
2108 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially | |
2109 | * unmapped vm_area_struct will remain in use: so lower split_vma | |
2110 | * places tmp vma above, and higher split_vma places tmp vma below. | |
2111 | */ | |
146425a3 | 2112 | if (start > vma->vm_start) { |
659ace58 KM |
2113 | int error; |
2114 | ||
2115 | /* | |
2116 | * Make sure that map_count on return from munmap() will | |
2117 | * not exceed its limit; but let map_count go just above | |
2118 | * its limit temporarily, to help free resources as expected. | |
2119 | */ | |
2120 | if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) | |
2121 | return -ENOMEM; | |
2122 | ||
2123 | error = __split_vma(mm, vma, start, 0); | |
1da177e4 LT |
2124 | if (error) |
2125 | return error; | |
146425a3 | 2126 | prev = vma; |
1da177e4 LT |
2127 | } |
2128 | ||
2129 | /* Does it split the last one? */ | |
2130 | last = find_vma(mm, end); | |
2131 | if (last && end > last->vm_start) { | |
659ace58 | 2132 | int error = __split_vma(mm, last, end, 1); |
1da177e4 LT |
2133 | if (error) |
2134 | return error; | |
2135 | } | |
146425a3 | 2136 | vma = prev? prev->vm_next: mm->mmap; |
1da177e4 | 2137 | |
ba470de4 RR |
2138 | /* |
2139 | * unlock any mlock()ed ranges before detaching vmas | |
2140 | */ | |
2141 | if (mm->locked_vm) { | |
2142 | struct vm_area_struct *tmp = vma; | |
2143 | while (tmp && tmp->vm_start < end) { | |
2144 | if (tmp->vm_flags & VM_LOCKED) { | |
2145 | mm->locked_vm -= vma_pages(tmp); | |
2146 | munlock_vma_pages_all(tmp); | |
2147 | } | |
2148 | tmp = tmp->vm_next; | |
2149 | } | |
2150 | } | |
2151 | ||
1da177e4 LT |
2152 | /* |
2153 | * Remove the vma's, and unmap the actual pages | |
2154 | */ | |
146425a3 HD |
2155 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
2156 | unmap_region(mm, vma, prev, start, end); | |
1da177e4 LT |
2157 | |
2158 | /* Fix up all other VM information */ | |
2c0b3814 | 2159 | remove_vma_list(mm, vma); |
1da177e4 LT |
2160 | |
2161 | return 0; | |
2162 | } | |
1da177e4 | 2163 | |
bfce281c | 2164 | int vm_munmap(unsigned long start, size_t len) |
1da177e4 LT |
2165 | { |
2166 | int ret; | |
bfce281c | 2167 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
2168 | |
2169 | down_write(&mm->mmap_sem); | |
a46ef99d | 2170 | ret = do_munmap(mm, start, len); |
1da177e4 LT |
2171 | up_write(&mm->mmap_sem); |
2172 | return ret; | |
2173 | } | |
a46ef99d LT |
2174 | EXPORT_SYMBOL(vm_munmap); |
2175 | ||
2176 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) | |
2177 | { | |
2178 | profile_munmap(addr); | |
bfce281c | 2179 | return vm_munmap(addr, len); |
a46ef99d | 2180 | } |
1da177e4 LT |
2181 | |
2182 | static inline void verify_mm_writelocked(struct mm_struct *mm) | |
2183 | { | |
a241ec65 | 2184 | #ifdef CONFIG_DEBUG_VM |
1da177e4 LT |
2185 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
2186 | WARN_ON(1); | |
2187 | up_read(&mm->mmap_sem); | |
2188 | } | |
2189 | #endif | |
2190 | } | |
2191 | ||
2192 | /* | |
2193 | * this is really a simplified "do_mmap". it only handles | |
2194 | * anonymous maps. eventually we may be able to do some | |
2195 | * brk-specific accounting here. | |
2196 | */ | |
e4eb1ff6 | 2197 | static unsigned long do_brk(unsigned long addr, unsigned long len) |
1da177e4 LT |
2198 | { |
2199 | struct mm_struct * mm = current->mm; | |
2200 | struct vm_area_struct * vma, * prev; | |
2201 | unsigned long flags; | |
2202 | struct rb_node ** rb_link, * rb_parent; | |
2203 | pgoff_t pgoff = addr >> PAGE_SHIFT; | |
3a459756 | 2204 | int error; |
1da177e4 LT |
2205 | |
2206 | len = PAGE_ALIGN(len); | |
2207 | if (!len) | |
2208 | return addr; | |
2209 | ||
3a459756 KK |
2210 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
2211 | ||
2c6a1016 AV |
2212 | error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); |
2213 | if (error & ~PAGE_MASK) | |
3a459756 KK |
2214 | return error; |
2215 | ||
1da177e4 LT |
2216 | /* |
2217 | * mlock MCL_FUTURE? | |
2218 | */ | |
2219 | if (mm->def_flags & VM_LOCKED) { | |
2220 | unsigned long locked, lock_limit; | |
93ea1d0a CW |
2221 | locked = len >> PAGE_SHIFT; |
2222 | locked += mm->locked_vm; | |
59e99e5b | 2223 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
93ea1d0a | 2224 | lock_limit >>= PAGE_SHIFT; |
1da177e4 LT |
2225 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
2226 | return -EAGAIN; | |
2227 | } | |
2228 | ||
2229 | /* | |
2230 | * mm->mmap_sem is required to protect against another thread | |
2231 | * changing the mappings in case we sleep. | |
2232 | */ | |
2233 | verify_mm_writelocked(mm); | |
2234 | ||
2235 | /* | |
2236 | * Clear old maps. this also does some error checking for us | |
2237 | */ | |
2238 | munmap_back: | |
6597d783 | 2239 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { |
1da177e4 LT |
2240 | if (do_munmap(mm, addr, len)) |
2241 | return -ENOMEM; | |
2242 | goto munmap_back; | |
2243 | } | |
2244 | ||
2245 | /* Check against address space limits *after* clearing old maps... */ | |
119f657c | 2246 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2247 | return -ENOMEM; |
2248 | ||
2249 | if (mm->map_count > sysctl_max_map_count) | |
2250 | return -ENOMEM; | |
2251 | ||
191c5424 | 2252 | if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) |
1da177e4 LT |
2253 | return -ENOMEM; |
2254 | ||
1da177e4 | 2255 | /* Can we just expand an old private anonymous mapping? */ |
ba470de4 RR |
2256 | vma = vma_merge(mm, prev, addr, addr + len, flags, |
2257 | NULL, NULL, pgoff, NULL); | |
2258 | if (vma) | |
1da177e4 LT |
2259 | goto out; |
2260 | ||
2261 | /* | |
2262 | * create a vma struct for an anonymous mapping | |
2263 | */ | |
c5e3b83e | 2264 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2265 | if (!vma) { |
2266 | vm_unacct_memory(len >> PAGE_SHIFT); | |
2267 | return -ENOMEM; | |
2268 | } | |
1da177e4 | 2269 | |
5beb4930 | 2270 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1da177e4 LT |
2271 | vma->vm_mm = mm; |
2272 | vma->vm_start = addr; | |
2273 | vma->vm_end = addr + len; | |
2274 | vma->vm_pgoff = pgoff; | |
2275 | vma->vm_flags = flags; | |
3ed75eb8 | 2276 | vma->vm_page_prot = vm_get_page_prot(flags); |
1da177e4 LT |
2277 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2278 | out: | |
3af9e859 | 2279 | perf_event_mmap(vma); |
1da177e4 LT |
2280 | mm->total_vm += len >> PAGE_SHIFT; |
2281 | if (flags & VM_LOCKED) { | |
ba470de4 RR |
2282 | if (!mlock_vma_pages_range(vma, addr, addr + len)) |
2283 | mm->locked_vm += (len >> PAGE_SHIFT); | |
1da177e4 LT |
2284 | } |
2285 | return addr; | |
2286 | } | |
2287 | ||
e4eb1ff6 LT |
2288 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
2289 | { | |
2290 | struct mm_struct *mm = current->mm; | |
2291 | unsigned long ret; | |
2292 | ||
2293 | down_write(&mm->mmap_sem); | |
2294 | ret = do_brk(addr, len); | |
2295 | up_write(&mm->mmap_sem); | |
2296 | return ret; | |
2297 | } | |
2298 | EXPORT_SYMBOL(vm_brk); | |
1da177e4 LT |
2299 | |
2300 | /* Release all mmaps. */ | |
2301 | void exit_mmap(struct mm_struct *mm) | |
2302 | { | |
d16dfc55 | 2303 | struct mmu_gather tlb; |
ba470de4 | 2304 | struct vm_area_struct *vma; |
1da177e4 LT |
2305 | unsigned long nr_accounted = 0; |
2306 | ||
d6dd61c8 | 2307 | /* mm's last user has gone, and its about to be pulled down */ |
cddb8a5c | 2308 | mmu_notifier_release(mm); |
d6dd61c8 | 2309 | |
ba470de4 RR |
2310 | if (mm->locked_vm) { |
2311 | vma = mm->mmap; | |
2312 | while (vma) { | |
2313 | if (vma->vm_flags & VM_LOCKED) | |
2314 | munlock_vma_pages_all(vma); | |
2315 | vma = vma->vm_next; | |
2316 | } | |
2317 | } | |
9480c53e JF |
2318 | |
2319 | arch_exit_mmap(mm); | |
2320 | ||
ba470de4 | 2321 | vma = mm->mmap; |
9480c53e JF |
2322 | if (!vma) /* Can happen if dup_mmap() received an OOM */ |
2323 | return; | |
2324 | ||
1da177e4 | 2325 | lru_add_drain(); |
1da177e4 | 2326 | flush_cache_mm(mm); |
d16dfc55 | 2327 | tlb_gather_mmu(&tlb, mm, 1); |
901608d9 | 2328 | /* update_hiwater_rss(mm) here? but nobody should be looking */ |
e0da382c | 2329 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
4f74d2c8 | 2330 | unmap_vmas(&tlb, vma, 0, -1); |
9ba69294 | 2331 | |
d16dfc55 | 2332 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
853f5e26 | 2333 | tlb_finish_mmu(&tlb, 0, -1); |
1da177e4 | 2334 | |
1da177e4 | 2335 | /* |
8f4f8c16 HD |
2336 | * Walk the list again, actually closing and freeing it, |
2337 | * with preemption enabled, without holding any MM locks. | |
1da177e4 | 2338 | */ |
4f74d2c8 LT |
2339 | while (vma) { |
2340 | if (vma->vm_flags & VM_ACCOUNT) | |
2341 | nr_accounted += vma_pages(vma); | |
a8fb5618 | 2342 | vma = remove_vma(vma); |
4f74d2c8 LT |
2343 | } |
2344 | vm_unacct_memory(nr_accounted); | |
e0da382c | 2345 | |
f9aed62a | 2346 | WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
1da177e4 LT |
2347 | } |
2348 | ||
2349 | /* Insert vm structure into process list sorted by address | |
2350 | * and into the inode's i_mmap tree. If vm_file is non-NULL | |
3d48ae45 | 2351 | * then i_mmap_mutex is taken here. |
1da177e4 | 2352 | */ |
6597d783 | 2353 | int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) |
1da177e4 | 2354 | { |
6597d783 HD |
2355 | struct vm_area_struct *prev; |
2356 | struct rb_node **rb_link, *rb_parent; | |
1da177e4 LT |
2357 | |
2358 | /* | |
2359 | * The vm_pgoff of a purely anonymous vma should be irrelevant | |
2360 | * until its first write fault, when page's anon_vma and index | |
2361 | * are set. But now set the vm_pgoff it will almost certainly | |
2362 | * end up with (unless mremap moves it elsewhere before that | |
2363 | * first wfault), so /proc/pid/maps tells a consistent story. | |
2364 | * | |
2365 | * By setting it to reflect the virtual start address of the | |
2366 | * vma, merges and splits can happen in a seamless way, just | |
2367 | * using the existing file pgoff checks and manipulations. | |
2368 | * Similarly in do_mmap_pgoff and in do_brk. | |
2369 | */ | |
2370 | if (!vma->vm_file) { | |
2371 | BUG_ON(vma->anon_vma); | |
2372 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; | |
2373 | } | |
6597d783 HD |
2374 | if (find_vma_links(mm, vma->vm_start, vma->vm_end, |
2375 | &prev, &rb_link, &rb_parent)) | |
1da177e4 | 2376 | return -ENOMEM; |
2fd4ef85 | 2377 | if ((vma->vm_flags & VM_ACCOUNT) && |
34b4e4aa | 2378 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
2fd4ef85 | 2379 | return -ENOMEM; |
2b144498 | 2380 | |
1da177e4 LT |
2381 | vma_link(mm, vma, prev, rb_link, rb_parent); |
2382 | return 0; | |
2383 | } | |
2384 | ||
2385 | /* | |
2386 | * Copy the vma structure to a new location in the same mm, | |
2387 | * prior to moving page table entries, to effect an mremap move. | |
2388 | */ | |
2389 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, | |
38a76013 ML |
2390 | unsigned long addr, unsigned long len, pgoff_t pgoff, |
2391 | bool *need_rmap_locks) | |
1da177e4 LT |
2392 | { |
2393 | struct vm_area_struct *vma = *vmap; | |
2394 | unsigned long vma_start = vma->vm_start; | |
2395 | struct mm_struct *mm = vma->vm_mm; | |
2396 | struct vm_area_struct *new_vma, *prev; | |
2397 | struct rb_node **rb_link, *rb_parent; | |
2398 | struct mempolicy *pol; | |
948f017b | 2399 | bool faulted_in_anon_vma = true; |
1da177e4 LT |
2400 | |
2401 | /* | |
2402 | * If anonymous vma has not yet been faulted, update new pgoff | |
2403 | * to match new location, to increase its chance of merging. | |
2404 | */ | |
948f017b | 2405 | if (unlikely(!vma->vm_file && !vma->anon_vma)) { |
1da177e4 | 2406 | pgoff = addr >> PAGE_SHIFT; |
948f017b AA |
2407 | faulted_in_anon_vma = false; |
2408 | } | |
1da177e4 | 2409 | |
6597d783 HD |
2410 | if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) |
2411 | return NULL; /* should never get here */ | |
1da177e4 LT |
2412 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
2413 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); | |
2414 | if (new_vma) { | |
2415 | /* | |
2416 | * Source vma may have been merged into new_vma | |
2417 | */ | |
948f017b AA |
2418 | if (unlikely(vma_start >= new_vma->vm_start && |
2419 | vma_start < new_vma->vm_end)) { | |
2420 | /* | |
2421 | * The only way we can get a vma_merge with | |
2422 | * self during an mremap is if the vma hasn't | |
2423 | * been faulted in yet and we were allowed to | |
2424 | * reset the dst vma->vm_pgoff to the | |
2425 | * destination address of the mremap to allow | |
2426 | * the merge to happen. mremap must change the | |
2427 | * vm_pgoff linearity between src and dst vmas | |
2428 | * (in turn preventing a vma_merge) to be | |
2429 | * safe. It is only safe to keep the vm_pgoff | |
2430 | * linear if there are no pages mapped yet. | |
2431 | */ | |
2432 | VM_BUG_ON(faulted_in_anon_vma); | |
38a76013 | 2433 | *vmap = vma = new_vma; |
108d6642 | 2434 | } |
38a76013 | 2435 | *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); |
1da177e4 | 2436 | } else { |
e94b1766 | 2437 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1da177e4 LT |
2438 | if (new_vma) { |
2439 | *new_vma = *vma; | |
523d4e20 ML |
2440 | new_vma->vm_start = addr; |
2441 | new_vma->vm_end = addr + len; | |
2442 | new_vma->vm_pgoff = pgoff; | |
846a16bf | 2443 | pol = mpol_dup(vma_policy(vma)); |
5beb4930 RR |
2444 | if (IS_ERR(pol)) |
2445 | goto out_free_vma; | |
523d4e20 | 2446 | vma_set_policy(new_vma, pol); |
5beb4930 RR |
2447 | INIT_LIST_HEAD(&new_vma->anon_vma_chain); |
2448 | if (anon_vma_clone(new_vma, vma)) | |
2449 | goto out_free_mempol; | |
e9714acf | 2450 | if (new_vma->vm_file) |
1da177e4 LT |
2451 | get_file(new_vma->vm_file); |
2452 | if (new_vma->vm_ops && new_vma->vm_ops->open) | |
2453 | new_vma->vm_ops->open(new_vma); | |
2454 | vma_link(mm, new_vma, prev, rb_link, rb_parent); | |
38a76013 | 2455 | *need_rmap_locks = false; |
1da177e4 LT |
2456 | } |
2457 | } | |
2458 | return new_vma; | |
5beb4930 RR |
2459 | |
2460 | out_free_mempol: | |
2461 | mpol_put(pol); | |
2462 | out_free_vma: | |
2463 | kmem_cache_free(vm_area_cachep, new_vma); | |
2464 | return NULL; | |
1da177e4 | 2465 | } |
119f657c | 2466 | |
2467 | /* | |
2468 | * Return true if the calling process may expand its vm space by the passed | |
2469 | * number of pages | |
2470 | */ | |
2471 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) | |
2472 | { | |
2473 | unsigned long cur = mm->total_vm; /* pages */ | |
2474 | unsigned long lim; | |
2475 | ||
59e99e5b | 2476 | lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; |
119f657c | 2477 | |
2478 | if (cur + npages > lim) | |
2479 | return 0; | |
2480 | return 1; | |
2481 | } | |
fa5dc22f RM |
2482 | |
2483 | ||
b1d0e4f5 NP |
2484 | static int special_mapping_fault(struct vm_area_struct *vma, |
2485 | struct vm_fault *vmf) | |
fa5dc22f | 2486 | { |
b1d0e4f5 | 2487 | pgoff_t pgoff; |
fa5dc22f RM |
2488 | struct page **pages; |
2489 | ||
b1d0e4f5 NP |
2490 | /* |
2491 | * special mappings have no vm_file, and in that case, the mm | |
2492 | * uses vm_pgoff internally. So we have to subtract it from here. | |
2493 | * We are allowed to do this because we are the mm; do not copy | |
2494 | * this code into drivers! | |
2495 | */ | |
2496 | pgoff = vmf->pgoff - vma->vm_pgoff; | |
fa5dc22f | 2497 | |
b1d0e4f5 NP |
2498 | for (pages = vma->vm_private_data; pgoff && *pages; ++pages) |
2499 | pgoff--; | |
fa5dc22f RM |
2500 | |
2501 | if (*pages) { | |
2502 | struct page *page = *pages; | |
2503 | get_page(page); | |
b1d0e4f5 NP |
2504 | vmf->page = page; |
2505 | return 0; | |
fa5dc22f RM |
2506 | } |
2507 | ||
b1d0e4f5 | 2508 | return VM_FAULT_SIGBUS; |
fa5dc22f RM |
2509 | } |
2510 | ||
2511 | /* | |
2512 | * Having a close hook prevents vma merging regardless of flags. | |
2513 | */ | |
2514 | static void special_mapping_close(struct vm_area_struct *vma) | |
2515 | { | |
2516 | } | |
2517 | ||
f0f37e2f | 2518 | static const struct vm_operations_struct special_mapping_vmops = { |
fa5dc22f | 2519 | .close = special_mapping_close, |
b1d0e4f5 | 2520 | .fault = special_mapping_fault, |
fa5dc22f RM |
2521 | }; |
2522 | ||
2523 | /* | |
2524 | * Called with mm->mmap_sem held for writing. | |
2525 | * Insert a new vma covering the given region, with the given flags. | |
2526 | * Its pages are supplied by the given array of struct page *. | |
2527 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. | |
2528 | * The region past the last page supplied will always produce SIGBUS. | |
2529 | * The array pointer and the pages it points to are assumed to stay alive | |
2530 | * for as long as this mapping might exist. | |
2531 | */ | |
2532 | int install_special_mapping(struct mm_struct *mm, | |
2533 | unsigned long addr, unsigned long len, | |
2534 | unsigned long vm_flags, struct page **pages) | |
2535 | { | |
462e635e | 2536 | int ret; |
fa5dc22f RM |
2537 | struct vm_area_struct *vma; |
2538 | ||
2539 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
2540 | if (unlikely(vma == NULL)) | |
2541 | return -ENOMEM; | |
2542 | ||
5beb4930 | 2543 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
fa5dc22f RM |
2544 | vma->vm_mm = mm; |
2545 | vma->vm_start = addr; | |
2546 | vma->vm_end = addr + len; | |
2547 | ||
2f98735c | 2548 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
3ed75eb8 | 2549 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
fa5dc22f RM |
2550 | |
2551 | vma->vm_ops = &special_mapping_vmops; | |
2552 | vma->vm_private_data = pages; | |
2553 | ||
462e635e TO |
2554 | ret = insert_vm_struct(mm, vma); |
2555 | if (ret) | |
2556 | goto out; | |
fa5dc22f RM |
2557 | |
2558 | mm->total_vm += len >> PAGE_SHIFT; | |
2559 | ||
cdd6c482 | 2560 | perf_event_mmap(vma); |
089dd79d | 2561 | |
fa5dc22f | 2562 | return 0; |
462e635e TO |
2563 | |
2564 | out: | |
2565 | kmem_cache_free(vm_area_cachep, vma); | |
2566 | return ret; | |
fa5dc22f | 2567 | } |
7906d00c AA |
2568 | |
2569 | static DEFINE_MUTEX(mm_all_locks_mutex); | |
2570 | ||
454ed842 | 2571 | static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) |
7906d00c | 2572 | { |
bf181b9f | 2573 | if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
2574 | /* |
2575 | * The LSB of head.next can't change from under us | |
2576 | * because we hold the mm_all_locks_mutex. | |
2577 | */ | |
2b575eb6 | 2578 | mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem); |
7906d00c AA |
2579 | /* |
2580 | * We can safely modify head.next after taking the | |
2b575eb6 | 2581 | * anon_vma->root->mutex. If some other vma in this mm shares |
7906d00c AA |
2582 | * the same anon_vma we won't take it again. |
2583 | * | |
2584 | * No need of atomic instructions here, head.next | |
2585 | * can't change from under us thanks to the | |
2b575eb6 | 2586 | * anon_vma->root->mutex. |
7906d00c AA |
2587 | */ |
2588 | if (__test_and_set_bit(0, (unsigned long *) | |
bf181b9f | 2589 | &anon_vma->root->rb_root.rb_node)) |
7906d00c AA |
2590 | BUG(); |
2591 | } | |
2592 | } | |
2593 | ||
454ed842 | 2594 | static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) |
7906d00c AA |
2595 | { |
2596 | if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2597 | /* | |
2598 | * AS_MM_ALL_LOCKS can't change from under us because | |
2599 | * we hold the mm_all_locks_mutex. | |
2600 | * | |
2601 | * Operations on ->flags have to be atomic because | |
2602 | * even if AS_MM_ALL_LOCKS is stable thanks to the | |
2603 | * mm_all_locks_mutex, there may be other cpus | |
2604 | * changing other bitflags in parallel to us. | |
2605 | */ | |
2606 | if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) | |
2607 | BUG(); | |
3d48ae45 | 2608 | mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); |
7906d00c AA |
2609 | } |
2610 | } | |
2611 | ||
2612 | /* | |
2613 | * This operation locks against the VM for all pte/vma/mm related | |
2614 | * operations that could ever happen on a certain mm. This includes | |
2615 | * vmtruncate, try_to_unmap, and all page faults. | |
2616 | * | |
2617 | * The caller must take the mmap_sem in write mode before calling | |
2618 | * mm_take_all_locks(). The caller isn't allowed to release the | |
2619 | * mmap_sem until mm_drop_all_locks() returns. | |
2620 | * | |
2621 | * mmap_sem in write mode is required in order to block all operations | |
2622 | * that could modify pagetables and free pages without need of | |
2623 | * altering the vma layout (for example populate_range() with | |
2624 | * nonlinear vmas). It's also needed in write mode to avoid new | |
2625 | * anon_vmas to be associated with existing vmas. | |
2626 | * | |
2627 | * A single task can't take more than one mm_take_all_locks() in a row | |
2628 | * or it would deadlock. | |
2629 | * | |
bf181b9f | 2630 | * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in |
7906d00c AA |
2631 | * mapping->flags avoid to take the same lock twice, if more than one |
2632 | * vma in this mm is backed by the same anon_vma or address_space. | |
2633 | * | |
2634 | * We can take all the locks in random order because the VM code | |
2b575eb6 | 2635 | * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never |
7906d00c AA |
2636 | * takes more than one of them in a row. Secondly we're protected |
2637 | * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. | |
2638 | * | |
2639 | * mm_take_all_locks() and mm_drop_all_locks are expensive operations | |
2640 | * that may have to take thousand of locks. | |
2641 | * | |
2642 | * mm_take_all_locks() can fail if it's interrupted by signals. | |
2643 | */ | |
2644 | int mm_take_all_locks(struct mm_struct *mm) | |
2645 | { | |
2646 | struct vm_area_struct *vma; | |
5beb4930 | 2647 | struct anon_vma_chain *avc; |
7906d00c AA |
2648 | |
2649 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2650 | ||
2651 | mutex_lock(&mm_all_locks_mutex); | |
2652 | ||
2653 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2654 | if (signal_pending(current)) | |
2655 | goto out_unlock; | |
7906d00c | 2656 | if (vma->vm_file && vma->vm_file->f_mapping) |
454ed842 | 2657 | vm_lock_mapping(mm, vma->vm_file->f_mapping); |
7906d00c | 2658 | } |
7cd5a02f PZ |
2659 | |
2660 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2661 | if (signal_pending(current)) | |
2662 | goto out_unlock; | |
2663 | if (vma->anon_vma) | |
5beb4930 RR |
2664 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2665 | vm_lock_anon_vma(mm, avc->anon_vma); | |
7906d00c | 2666 | } |
7cd5a02f | 2667 | |
584cff54 | 2668 | return 0; |
7906d00c AA |
2669 | |
2670 | out_unlock: | |
584cff54 KC |
2671 | mm_drop_all_locks(mm); |
2672 | return -EINTR; | |
7906d00c AA |
2673 | } |
2674 | ||
2675 | static void vm_unlock_anon_vma(struct anon_vma *anon_vma) | |
2676 | { | |
bf181b9f | 2677 | if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { |
7906d00c AA |
2678 | /* |
2679 | * The LSB of head.next can't change to 0 from under | |
2680 | * us because we hold the mm_all_locks_mutex. | |
2681 | * | |
2682 | * We must however clear the bitflag before unlocking | |
bf181b9f | 2683 | * the vma so the users using the anon_vma->rb_root will |
7906d00c AA |
2684 | * never see our bitflag. |
2685 | * | |
2686 | * No need of atomic instructions here, head.next | |
2687 | * can't change from under us until we release the | |
2b575eb6 | 2688 | * anon_vma->root->mutex. |
7906d00c AA |
2689 | */ |
2690 | if (!__test_and_clear_bit(0, (unsigned long *) | |
bf181b9f | 2691 | &anon_vma->root->rb_root.rb_node)) |
7906d00c | 2692 | BUG(); |
cba48b98 | 2693 | anon_vma_unlock(anon_vma); |
7906d00c AA |
2694 | } |
2695 | } | |
2696 | ||
2697 | static void vm_unlock_mapping(struct address_space *mapping) | |
2698 | { | |
2699 | if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { | |
2700 | /* | |
2701 | * AS_MM_ALL_LOCKS can't change to 0 from under us | |
2702 | * because we hold the mm_all_locks_mutex. | |
2703 | */ | |
3d48ae45 | 2704 | mutex_unlock(&mapping->i_mmap_mutex); |
7906d00c AA |
2705 | if (!test_and_clear_bit(AS_MM_ALL_LOCKS, |
2706 | &mapping->flags)) | |
2707 | BUG(); | |
2708 | } | |
2709 | } | |
2710 | ||
2711 | /* | |
2712 | * The mmap_sem cannot be released by the caller until | |
2713 | * mm_drop_all_locks() returns. | |
2714 | */ | |
2715 | void mm_drop_all_locks(struct mm_struct *mm) | |
2716 | { | |
2717 | struct vm_area_struct *vma; | |
5beb4930 | 2718 | struct anon_vma_chain *avc; |
7906d00c AA |
2719 | |
2720 | BUG_ON(down_read_trylock(&mm->mmap_sem)); | |
2721 | BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); | |
2722 | ||
2723 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
2724 | if (vma->anon_vma) | |
5beb4930 RR |
2725 | list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) |
2726 | vm_unlock_anon_vma(avc->anon_vma); | |
7906d00c AA |
2727 | if (vma->vm_file && vma->vm_file->f_mapping) |
2728 | vm_unlock_mapping(vma->vm_file->f_mapping); | |
2729 | } | |
2730 | ||
2731 | mutex_unlock(&mm_all_locks_mutex); | |
2732 | } | |
8feae131 DH |
2733 | |
2734 | /* | |
2735 | * initialise the VMA slab | |
2736 | */ | |
2737 | void __init mmap_init(void) | |
2738 | { | |
00a62ce9 KM |
2739 | int ret; |
2740 | ||
2741 | ret = percpu_counter_init(&vm_committed_as, 0); | |
2742 | VM_BUG_ON(ret); | |
8feae131 | 2743 | } |