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