Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * mm/mmap.c |
| 3 | * |
| 4 | * Written by obz. |
| 5 | * |
| 6 | * Address space accounting code <alan@redhat.com> |
| 7 | */ |
| 8 | |
| 9 | #include <linux/slab.h> |
Alexey Dobriyan | 4af3c9c | 2007-10-16 23:29:23 -0700 | [diff] [blame] | 10 | #include <linux/backing-dev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 17 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
| 30 | #include <asm/uaccess.h> |
| 31 | #include <asm/cacheflush.h> |
| 32 | #include <asm/tlb.h> |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 33 | #include <asm/mmu_context.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 35 | #ifndef arch_mmap_check |
| 36 | #define arch_mmap_check(addr, len, flags) (0) |
| 37 | #endif |
| 38 | |
Martin Schwidefsky | 08e7d9b | 2008-02-04 22:29:16 -0800 | [diff] [blame] | 39 | #ifndef arch_rebalance_pgtables |
| 40 | #define arch_rebalance_pgtables(addr, len) (addr) |
| 41 | #endif |
| 42 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 43 | static void unmap_region(struct mm_struct *mm, |
| 44 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
| 45 | unsigned long start, unsigned long end); |
| 46 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | /* |
| 48 | * WARNING: the debugging will use recursive algorithms so never enable this |
| 49 | * unless you know what you are doing. |
| 50 | */ |
| 51 | #undef DEBUG_MM_RB |
| 52 | |
| 53 | /* description of effects of mapping type and prot in current implementation. |
| 54 | * this is due to the limited x86 page protection hardware. The expected |
| 55 | * behavior is in parens: |
| 56 | * |
| 57 | * map_type prot |
| 58 | * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC |
| 59 | * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
| 60 | * w: (no) no w: (no) no w: (yes) yes w: (no) no |
| 61 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
| 62 | * |
| 63 | * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes |
| 64 | * w: (no) no w: (no) no w: (copy) copy w: (no) no |
| 65 | * x: (no) no x: (no) yes x: (no) yes x: (yes) yes |
| 66 | * |
| 67 | */ |
| 68 | pgprot_t protection_map[16] = { |
| 69 | __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, |
| 70 | __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 |
| 71 | }; |
| 72 | |
Hugh Dickins | 804af2c | 2006-07-26 21:39:49 +0100 | [diff] [blame] | 73 | pgprot_t vm_get_page_prot(unsigned long vm_flags) |
| 74 | { |
| 75 | return protection_map[vm_flags & |
| 76 | (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; |
| 77 | } |
| 78 | EXPORT_SYMBOL(vm_get_page_prot); |
| 79 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
| 81 | int sysctl_overcommit_ratio = 50; /* default is 50% */ |
Christoph Lameter | c3d8c14 | 2005-09-06 15:16:33 -0700 | [diff] [blame] | 82 | int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | atomic_t vm_committed_space = ATOMIC_INIT(0); |
| 84 | |
| 85 | /* |
| 86 | * Check that a process has enough memory to allocate a new virtual |
| 87 | * mapping. 0 means there is enough memory for the allocation to |
| 88 | * succeed and -ENOMEM implies there is not. |
| 89 | * |
| 90 | * We currently support three overcommit policies, which are set via the |
| 91 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
| 92 | * |
| 93 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
| 94 | * Additional code 2002 Jul 20 by Robert Love. |
| 95 | * |
| 96 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
| 97 | * |
| 98 | * Note this is a helper function intended to be used by LSMs which |
| 99 | * wish to use this logic. |
| 100 | */ |
Alan Cox | 34b4e4a | 2007-08-22 14:01:28 -0700 | [diff] [blame] | 101 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | { |
| 103 | unsigned long free, allowed; |
| 104 | |
| 105 | vm_acct_memory(pages); |
| 106 | |
| 107 | /* |
| 108 | * Sometimes we want to use more memory than we have |
| 109 | */ |
| 110 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
| 111 | return 0; |
| 112 | |
| 113 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
| 114 | unsigned long n; |
| 115 | |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 116 | free = global_page_state(NR_FILE_PAGES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | free += nr_swap_pages; |
| 118 | |
| 119 | /* |
| 120 | * Any slabs which are created with the |
| 121 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
| 122 | * which are reclaimable, under pressure. The dentry |
| 123 | * cache and most inode caches should fall into this |
| 124 | */ |
Christoph Lameter | 972d1a7 | 2006-09-25 23:31:51 -0700 | [diff] [blame] | 125 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
| 127 | /* |
| 128 | * Leave the last 3% for root |
| 129 | */ |
| 130 | if (!cap_sys_admin) |
| 131 | free -= free / 32; |
| 132 | |
| 133 | if (free > pages) |
| 134 | return 0; |
| 135 | |
| 136 | /* |
| 137 | * nr_free_pages() is very expensive on large systems, |
| 138 | * only call if we're about to fail. |
| 139 | */ |
| 140 | n = nr_free_pages(); |
Hideo AOKI | 6d9f783 | 2006-04-10 22:53:00 -0700 | [diff] [blame] | 141 | |
| 142 | /* |
| 143 | * Leave reserved pages. The pages are not for anonymous pages. |
| 144 | */ |
| 145 | if (n <= totalreserve_pages) |
| 146 | goto error; |
| 147 | else |
| 148 | n -= totalreserve_pages; |
| 149 | |
| 150 | /* |
| 151 | * Leave the last 3% for root |
| 152 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | if (!cap_sys_admin) |
| 154 | n -= n / 32; |
| 155 | free += n; |
| 156 | |
| 157 | if (free > pages) |
| 158 | return 0; |
Hideo AOKI | 6d9f783 | 2006-04-10 22:53:00 -0700 | [diff] [blame] | 159 | |
| 160 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | } |
| 162 | |
| 163 | allowed = (totalram_pages - hugetlb_total_pages()) |
| 164 | * sysctl_overcommit_ratio / 100; |
| 165 | /* |
| 166 | * Leave the last 3% for root |
| 167 | */ |
| 168 | if (!cap_sys_admin) |
| 169 | allowed -= allowed / 32; |
| 170 | allowed += total_swap_pages; |
| 171 | |
| 172 | /* Don't let a single process grow too big: |
| 173 | leave 3% of the size of this process for other processes */ |
Alan Cox | 34b4e4a | 2007-08-22 14:01:28 -0700 | [diff] [blame] | 174 | allowed -= mm->total_vm / 32; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | |
Simon Derr | 2f60f8d | 2005-08-04 19:52:03 -0700 | [diff] [blame] | 176 | /* |
| 177 | * cast `allowed' as a signed long because vm_committed_space |
| 178 | * sometimes has a negative value |
| 179 | */ |
| 180 | if (atomic_read(&vm_committed_space) < (long)allowed) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | return 0; |
Hideo AOKI | 6d9f783 | 2006-04-10 22:53:00 -0700 | [diff] [blame] | 182 | error: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | vm_unacct_memory(pages); |
| 184 | |
| 185 | return -ENOMEM; |
| 186 | } |
| 187 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | /* |
| 189 | * Requires inode->i_mapping->i_mmap_lock |
| 190 | */ |
| 191 | static void __remove_shared_vm_struct(struct vm_area_struct *vma, |
| 192 | struct file *file, struct address_space *mapping) |
| 193 | { |
| 194 | if (vma->vm_flags & VM_DENYWRITE) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 195 | atomic_inc(&file->f_path.dentry->d_inode->i_writecount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | if (vma->vm_flags & VM_SHARED) |
| 197 | mapping->i_mmap_writable--; |
| 198 | |
| 199 | flush_dcache_mmap_lock(mapping); |
| 200 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
| 201 | list_del_init(&vma->shared.vm_set.list); |
| 202 | else |
| 203 | vma_prio_tree_remove(vma, &mapping->i_mmap); |
| 204 | flush_dcache_mmap_unlock(mapping); |
| 205 | } |
| 206 | |
| 207 | /* |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 208 | * Unlink a file-based vm structure from its prio_tree, to hide |
| 209 | * vma from rmap and vmtruncate before freeing its page tables. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | */ |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 211 | void unlink_file_vma(struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | { |
| 213 | struct file *file = vma->vm_file; |
| 214 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | if (file) { |
| 216 | struct address_space *mapping = file->f_mapping; |
| 217 | spin_lock(&mapping->i_mmap_lock); |
| 218 | __remove_shared_vm_struct(vma, file, mapping); |
| 219 | spin_unlock(&mapping->i_mmap_lock); |
| 220 | } |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 221 | } |
| 222 | |
| 223 | /* |
| 224 | * Close a vm structure and free it, returning the next. |
| 225 | */ |
| 226 | static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) |
| 227 | { |
| 228 | struct vm_area_struct *next = vma->vm_next; |
| 229 | |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 230 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | if (vma->vm_ops && vma->vm_ops->close) |
| 232 | vma->vm_ops->close(vma); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 233 | if (vma->vm_file) |
| 234 | fput(vma->vm_file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | mpol_free(vma_policy(vma)); |
| 236 | kmem_cache_free(vm_area_cachep, vma); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 237 | return next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | } |
| 239 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | asmlinkage unsigned long sys_brk(unsigned long brk) |
| 241 | { |
| 242 | unsigned long rlim, retval; |
| 243 | unsigned long newbrk, oldbrk; |
| 244 | struct mm_struct *mm = current->mm; |
| 245 | |
| 246 | down_write(&mm->mmap_sem); |
| 247 | |
| 248 | if (brk < mm->end_code) |
| 249 | goto out; |
Ram Gupta | 1e62419 | 2006-04-10 22:52:57 -0700 | [diff] [blame] | 250 | |
| 251 | /* |
| 252 | * Check against rlimit here. If this check is done later after the test |
| 253 | * of oldbrk with newbrk then it can escape the test and let the data |
| 254 | * segment grow beyond its set limit the in case where the limit is |
| 255 | * not page aligned -Ram Gupta |
| 256 | */ |
| 257 | rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; |
Jiri Kosina | c1d171a | 2008-01-30 13:30:40 +0100 | [diff] [blame] | 258 | if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + |
| 259 | (mm->end_data - mm->start_data) > rlim) |
Ram Gupta | 1e62419 | 2006-04-10 22:52:57 -0700 | [diff] [blame] | 260 | goto out; |
| 261 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | newbrk = PAGE_ALIGN(brk); |
| 263 | oldbrk = PAGE_ALIGN(mm->brk); |
| 264 | if (oldbrk == newbrk) |
| 265 | goto set_brk; |
| 266 | |
| 267 | /* Always allow shrinking brk. */ |
| 268 | if (brk <= mm->brk) { |
| 269 | if (!do_munmap(mm, newbrk, oldbrk-newbrk)) |
| 270 | goto set_brk; |
| 271 | goto out; |
| 272 | } |
| 273 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | /* Check against existing mmap mappings. */ |
| 275 | if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) |
| 276 | goto out; |
| 277 | |
| 278 | /* Ok, looks good - let it rip. */ |
| 279 | if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) |
| 280 | goto out; |
| 281 | set_brk: |
| 282 | mm->brk = brk; |
| 283 | out: |
| 284 | retval = mm->brk; |
| 285 | up_write(&mm->mmap_sem); |
| 286 | return retval; |
| 287 | } |
| 288 | |
| 289 | #ifdef DEBUG_MM_RB |
| 290 | static int browse_rb(struct rb_root *root) |
| 291 | { |
| 292 | int i = 0, j; |
| 293 | struct rb_node *nd, *pn = NULL; |
| 294 | unsigned long prev = 0, pend = 0; |
| 295 | |
| 296 | for (nd = rb_first(root); nd; nd = rb_next(nd)) { |
| 297 | struct vm_area_struct *vma; |
| 298 | vma = rb_entry(nd, struct vm_area_struct, vm_rb); |
| 299 | if (vma->vm_start < prev) |
| 300 | printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; |
| 301 | if (vma->vm_start < pend) |
| 302 | printk("vm_start %lx pend %lx\n", vma->vm_start, pend); |
| 303 | if (vma->vm_start > vma->vm_end) |
| 304 | printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); |
| 305 | i++; |
| 306 | pn = nd; |
David Miller | d1af65d | 2007-02-28 20:13:13 -0800 | [diff] [blame] | 307 | prev = vma->vm_start; |
| 308 | pend = vma->vm_end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | } |
| 310 | j = 0; |
| 311 | for (nd = pn; nd; nd = rb_prev(nd)) { |
| 312 | j++; |
| 313 | } |
| 314 | if (i != j) |
| 315 | printk("backwards %d, forwards %d\n", j, i), i = 0; |
| 316 | return i; |
| 317 | } |
| 318 | |
| 319 | void validate_mm(struct mm_struct *mm) |
| 320 | { |
| 321 | int bug = 0; |
| 322 | int i = 0; |
| 323 | struct vm_area_struct *tmp = mm->mmap; |
| 324 | while (tmp) { |
| 325 | tmp = tmp->vm_next; |
| 326 | i++; |
| 327 | } |
| 328 | if (i != mm->map_count) |
| 329 | printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; |
| 330 | i = browse_rb(&mm->mm_rb); |
| 331 | if (i != mm->map_count) |
| 332 | printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; |
Eric Sesterhenn | 46a350e | 2006-04-01 01:23:29 +0200 | [diff] [blame] | 333 | BUG_ON(bug); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | } |
| 335 | #else |
| 336 | #define validate_mm(mm) do { } while (0) |
| 337 | #endif |
| 338 | |
| 339 | static struct vm_area_struct * |
| 340 | find_vma_prepare(struct mm_struct *mm, unsigned long addr, |
| 341 | struct vm_area_struct **pprev, struct rb_node ***rb_link, |
| 342 | struct rb_node ** rb_parent) |
| 343 | { |
| 344 | struct vm_area_struct * vma; |
| 345 | struct rb_node ** __rb_link, * __rb_parent, * rb_prev; |
| 346 | |
| 347 | __rb_link = &mm->mm_rb.rb_node; |
| 348 | rb_prev = __rb_parent = NULL; |
| 349 | vma = NULL; |
| 350 | |
| 351 | while (*__rb_link) { |
| 352 | struct vm_area_struct *vma_tmp; |
| 353 | |
| 354 | __rb_parent = *__rb_link; |
| 355 | vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); |
| 356 | |
| 357 | if (vma_tmp->vm_end > addr) { |
| 358 | vma = vma_tmp; |
| 359 | if (vma_tmp->vm_start <= addr) |
| 360 | return vma; |
| 361 | __rb_link = &__rb_parent->rb_left; |
| 362 | } else { |
| 363 | rb_prev = __rb_parent; |
| 364 | __rb_link = &__rb_parent->rb_right; |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | *pprev = NULL; |
| 369 | if (rb_prev) |
| 370 | *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
| 371 | *rb_link = __rb_link; |
| 372 | *rb_parent = __rb_parent; |
| 373 | return vma; |
| 374 | } |
| 375 | |
| 376 | static inline void |
| 377 | __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
| 378 | struct vm_area_struct *prev, struct rb_node *rb_parent) |
| 379 | { |
| 380 | if (prev) { |
| 381 | vma->vm_next = prev->vm_next; |
| 382 | prev->vm_next = vma; |
| 383 | } else { |
| 384 | mm->mmap = vma; |
| 385 | if (rb_parent) |
| 386 | vma->vm_next = rb_entry(rb_parent, |
| 387 | struct vm_area_struct, vm_rb); |
| 388 | else |
| 389 | vma->vm_next = NULL; |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, |
| 394 | struct rb_node **rb_link, struct rb_node *rb_parent) |
| 395 | { |
| 396 | rb_link_node(&vma->vm_rb, rb_parent, rb_link); |
| 397 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
| 398 | } |
| 399 | |
| 400 | static inline void __vma_link_file(struct vm_area_struct *vma) |
| 401 | { |
| 402 | struct file * file; |
| 403 | |
| 404 | file = vma->vm_file; |
| 405 | if (file) { |
| 406 | struct address_space *mapping = file->f_mapping; |
| 407 | |
| 408 | if (vma->vm_flags & VM_DENYWRITE) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 409 | atomic_dec(&file->f_path.dentry->d_inode->i_writecount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 410 | if (vma->vm_flags & VM_SHARED) |
| 411 | mapping->i_mmap_writable++; |
| 412 | |
| 413 | flush_dcache_mmap_lock(mapping); |
| 414 | if (unlikely(vma->vm_flags & VM_NONLINEAR)) |
| 415 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); |
| 416 | else |
| 417 | vma_prio_tree_insert(vma, &mapping->i_mmap); |
| 418 | flush_dcache_mmap_unlock(mapping); |
| 419 | } |
| 420 | } |
| 421 | |
| 422 | static void |
| 423 | __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
| 424 | struct vm_area_struct *prev, struct rb_node **rb_link, |
| 425 | struct rb_node *rb_parent) |
| 426 | { |
| 427 | __vma_link_list(mm, vma, prev, rb_parent); |
| 428 | __vma_link_rb(mm, vma, rb_link, rb_parent); |
| 429 | __anon_vma_link(vma); |
| 430 | } |
| 431 | |
| 432 | static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, |
| 433 | struct vm_area_struct *prev, struct rb_node **rb_link, |
| 434 | struct rb_node *rb_parent) |
| 435 | { |
| 436 | struct address_space *mapping = NULL; |
| 437 | |
| 438 | if (vma->vm_file) |
| 439 | mapping = vma->vm_file->f_mapping; |
| 440 | |
| 441 | if (mapping) { |
| 442 | spin_lock(&mapping->i_mmap_lock); |
| 443 | vma->vm_truncate_count = mapping->truncate_count; |
| 444 | } |
| 445 | anon_vma_lock(vma); |
| 446 | |
| 447 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
| 448 | __vma_link_file(vma); |
| 449 | |
| 450 | anon_vma_unlock(vma); |
| 451 | if (mapping) |
| 452 | spin_unlock(&mapping->i_mmap_lock); |
| 453 | |
| 454 | mm->map_count++; |
| 455 | validate_mm(mm); |
| 456 | } |
| 457 | |
| 458 | /* |
| 459 | * Helper for vma_adjust in the split_vma insert case: |
| 460 | * insert vm structure into list and rbtree and anon_vma, |
| 461 | * but it has already been inserted into prio_tree earlier. |
| 462 | */ |
| 463 | static void |
| 464 | __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
| 465 | { |
| 466 | struct vm_area_struct * __vma, * prev; |
| 467 | struct rb_node ** rb_link, * rb_parent; |
| 468 | |
| 469 | __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); |
Eric Sesterhenn | 46a350e | 2006-04-01 01:23:29 +0200 | [diff] [blame] | 470 | BUG_ON(__vma && __vma->vm_start < vma->vm_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | __vma_link(mm, vma, prev, rb_link, rb_parent); |
| 472 | mm->map_count++; |
| 473 | } |
| 474 | |
| 475 | static inline void |
| 476 | __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, |
| 477 | struct vm_area_struct *prev) |
| 478 | { |
| 479 | prev->vm_next = vma->vm_next; |
| 480 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
| 481 | if (mm->mmap_cache == vma) |
| 482 | mm->mmap_cache = prev; |
| 483 | } |
| 484 | |
| 485 | /* |
| 486 | * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that |
| 487 | * is already present in an i_mmap tree without adjusting the tree. |
| 488 | * The following helper function should be used when such adjustments |
| 489 | * are necessary. The "insert" vma (if any) is to be inserted |
| 490 | * before we drop the necessary locks. |
| 491 | */ |
| 492 | void vma_adjust(struct vm_area_struct *vma, unsigned long start, |
| 493 | unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) |
| 494 | { |
| 495 | struct mm_struct *mm = vma->vm_mm; |
| 496 | struct vm_area_struct *next = vma->vm_next; |
| 497 | struct vm_area_struct *importer = NULL; |
| 498 | struct address_space *mapping = NULL; |
| 499 | struct prio_tree_root *root = NULL; |
| 500 | struct file *file = vma->vm_file; |
| 501 | struct anon_vma *anon_vma = NULL; |
| 502 | long adjust_next = 0; |
| 503 | int remove_next = 0; |
| 504 | |
| 505 | if (next && !insert) { |
| 506 | if (end >= next->vm_end) { |
| 507 | /* |
| 508 | * vma expands, overlapping all the next, and |
| 509 | * perhaps the one after too (mprotect case 6). |
| 510 | */ |
| 511 | again: remove_next = 1 + (end > next->vm_end); |
| 512 | end = next->vm_end; |
| 513 | anon_vma = next->anon_vma; |
| 514 | importer = vma; |
| 515 | } else if (end > next->vm_start) { |
| 516 | /* |
| 517 | * vma expands, overlapping part of the next: |
| 518 | * mprotect case 5 shifting the boundary up. |
| 519 | */ |
| 520 | adjust_next = (end - next->vm_start) >> PAGE_SHIFT; |
| 521 | anon_vma = next->anon_vma; |
| 522 | importer = vma; |
| 523 | } else if (end < vma->vm_end) { |
| 524 | /* |
| 525 | * vma shrinks, and !insert tells it's not |
| 526 | * split_vma inserting another: so it must be |
| 527 | * mprotect case 4 shifting the boundary down. |
| 528 | */ |
| 529 | adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); |
| 530 | anon_vma = next->anon_vma; |
| 531 | importer = next; |
| 532 | } |
| 533 | } |
| 534 | |
| 535 | if (file) { |
| 536 | mapping = file->f_mapping; |
| 537 | if (!(vma->vm_flags & VM_NONLINEAR)) |
| 538 | root = &mapping->i_mmap; |
| 539 | spin_lock(&mapping->i_mmap_lock); |
| 540 | if (importer && |
| 541 | vma->vm_truncate_count != next->vm_truncate_count) { |
| 542 | /* |
| 543 | * unmap_mapping_range might be in progress: |
| 544 | * ensure that the expanding vma is rescanned. |
| 545 | */ |
| 546 | importer->vm_truncate_count = 0; |
| 547 | } |
| 548 | if (insert) { |
| 549 | insert->vm_truncate_count = vma->vm_truncate_count; |
| 550 | /* |
| 551 | * Put into prio_tree now, so instantiated pages |
| 552 | * are visible to arm/parisc __flush_dcache_page |
| 553 | * throughout; but we cannot insert into address |
| 554 | * space until vma start or end is updated. |
| 555 | */ |
| 556 | __vma_link_file(insert); |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | /* |
| 561 | * When changing only vma->vm_end, we don't really need |
| 562 | * anon_vma lock: but is that case worth optimizing out? |
| 563 | */ |
| 564 | if (vma->anon_vma) |
| 565 | anon_vma = vma->anon_vma; |
| 566 | if (anon_vma) { |
| 567 | spin_lock(&anon_vma->lock); |
| 568 | /* |
| 569 | * Easily overlooked: when mprotect shifts the boundary, |
| 570 | * make sure the expanding vma has anon_vma set if the |
| 571 | * shrinking vma had, to cover any anon pages imported. |
| 572 | */ |
| 573 | if (importer && !importer->anon_vma) { |
| 574 | importer->anon_vma = anon_vma; |
| 575 | __anon_vma_link(importer); |
| 576 | } |
| 577 | } |
| 578 | |
| 579 | if (root) { |
| 580 | flush_dcache_mmap_lock(mapping); |
| 581 | vma_prio_tree_remove(vma, root); |
| 582 | if (adjust_next) |
| 583 | vma_prio_tree_remove(next, root); |
| 584 | } |
| 585 | |
| 586 | vma->vm_start = start; |
| 587 | vma->vm_end = end; |
| 588 | vma->vm_pgoff = pgoff; |
| 589 | if (adjust_next) { |
| 590 | next->vm_start += adjust_next << PAGE_SHIFT; |
| 591 | next->vm_pgoff += adjust_next; |
| 592 | } |
| 593 | |
| 594 | if (root) { |
| 595 | if (adjust_next) |
| 596 | vma_prio_tree_insert(next, root); |
| 597 | vma_prio_tree_insert(vma, root); |
| 598 | flush_dcache_mmap_unlock(mapping); |
| 599 | } |
| 600 | |
| 601 | if (remove_next) { |
| 602 | /* |
| 603 | * vma_merge has merged next into vma, and needs |
| 604 | * us to remove next before dropping the locks. |
| 605 | */ |
| 606 | __vma_unlink(mm, next, vma); |
| 607 | if (file) |
| 608 | __remove_shared_vm_struct(next, file, mapping); |
| 609 | if (next->anon_vma) |
| 610 | __anon_vma_merge(vma, next); |
| 611 | } else if (insert) { |
| 612 | /* |
| 613 | * split_vma has split insert from vma, and needs |
| 614 | * us to insert it before dropping the locks |
| 615 | * (it may either follow vma or precede it). |
| 616 | */ |
| 617 | __insert_vm_struct(mm, insert); |
| 618 | } |
| 619 | |
| 620 | if (anon_vma) |
| 621 | spin_unlock(&anon_vma->lock); |
| 622 | if (mapping) |
| 623 | spin_unlock(&mapping->i_mmap_lock); |
| 624 | |
| 625 | if (remove_next) { |
| 626 | if (file) |
| 627 | fput(file); |
| 628 | mm->map_count--; |
| 629 | mpol_free(vma_policy(next)); |
| 630 | kmem_cache_free(vm_area_cachep, next); |
| 631 | /* |
| 632 | * In mprotect's case 6 (see comments on vma_merge), |
| 633 | * we must remove another next too. It would clutter |
| 634 | * up the code too much to do both in one go. |
| 635 | */ |
| 636 | if (remove_next == 2) { |
| 637 | next = vma->vm_next; |
| 638 | goto again; |
| 639 | } |
| 640 | } |
| 641 | |
| 642 | validate_mm(mm); |
| 643 | } |
| 644 | |
| 645 | /* |
| 646 | * If the vma has a ->close operation then the driver probably needs to release |
| 647 | * per-vma resources, so we don't attempt to merge those. |
| 648 | */ |
Hugh Dickins | a6f563d | 2006-03-22 00:08:29 -0800 | [diff] [blame] | 649 | #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | |
| 651 | static inline int is_mergeable_vma(struct vm_area_struct *vma, |
| 652 | struct file *file, unsigned long vm_flags) |
| 653 | { |
| 654 | if (vma->vm_flags != vm_flags) |
| 655 | return 0; |
| 656 | if (vma->vm_file != file) |
| 657 | return 0; |
| 658 | if (vma->vm_ops && vma->vm_ops->close) |
| 659 | return 0; |
| 660 | return 1; |
| 661 | } |
| 662 | |
| 663 | static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, |
| 664 | struct anon_vma *anon_vma2) |
| 665 | { |
| 666 | return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2); |
| 667 | } |
| 668 | |
| 669 | /* |
| 670 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
| 671 | * in front of (at a lower virtual address and file offset than) the vma. |
| 672 | * |
| 673 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
| 674 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
| 675 | * |
| 676 | * We don't check here for the merged mmap wrapping around the end of pagecache |
| 677 | * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which |
| 678 | * wrap, nor mmaps which cover the final page at index -1UL. |
| 679 | */ |
| 680 | static int |
| 681 | can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, |
| 682 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
| 683 | { |
| 684 | if (is_mergeable_vma(vma, file, vm_flags) && |
| 685 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { |
| 686 | if (vma->vm_pgoff == vm_pgoff) |
| 687 | return 1; |
| 688 | } |
| 689 | return 0; |
| 690 | } |
| 691 | |
| 692 | /* |
| 693 | * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) |
| 694 | * beyond (at a higher virtual address and file offset than) the vma. |
| 695 | * |
| 696 | * We cannot merge two vmas if they have differently assigned (non-NULL) |
| 697 | * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. |
| 698 | */ |
| 699 | static int |
| 700 | can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, |
| 701 | struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) |
| 702 | { |
| 703 | if (is_mergeable_vma(vma, file, vm_flags) && |
| 704 | is_mergeable_anon_vma(anon_vma, vma->anon_vma)) { |
| 705 | pgoff_t vm_pglen; |
| 706 | vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; |
| 707 | if (vma->vm_pgoff + vm_pglen == vm_pgoff) |
| 708 | return 1; |
| 709 | } |
| 710 | return 0; |
| 711 | } |
| 712 | |
| 713 | /* |
| 714 | * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out |
| 715 | * whether that can be merged with its predecessor or its successor. |
| 716 | * Or both (it neatly fills a hole). |
| 717 | * |
| 718 | * In most cases - when called for mmap, brk or mremap - [addr,end) is |
| 719 | * certain not to be mapped by the time vma_merge is called; but when |
| 720 | * called for mprotect, it is certain to be already mapped (either at |
| 721 | * an offset within prev, or at the start of next), and the flags of |
| 722 | * this area are about to be changed to vm_flags - and the no-change |
| 723 | * case has already been eliminated. |
| 724 | * |
| 725 | * The following mprotect cases have to be considered, where AAAA is |
| 726 | * the area passed down from mprotect_fixup, never extending beyond one |
| 727 | * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: |
| 728 | * |
| 729 | * AAAA AAAA AAAA AAAA |
| 730 | * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX |
| 731 | * cannot merge might become might become might become |
| 732 | * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or |
| 733 | * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or |
| 734 | * mremap move: PPPPNNNNNNNN 8 |
| 735 | * AAAA |
| 736 | * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN |
| 737 | * might become case 1 below case 2 below case 3 below |
| 738 | * |
| 739 | * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: |
| 740 | * mprotect_fixup updates vm_flags & vm_page_prot on successful return. |
| 741 | */ |
| 742 | struct vm_area_struct *vma_merge(struct mm_struct *mm, |
| 743 | struct vm_area_struct *prev, unsigned long addr, |
| 744 | unsigned long end, unsigned long vm_flags, |
| 745 | struct anon_vma *anon_vma, struct file *file, |
| 746 | pgoff_t pgoff, struct mempolicy *policy) |
| 747 | { |
| 748 | pgoff_t pglen = (end - addr) >> PAGE_SHIFT; |
| 749 | struct vm_area_struct *area, *next; |
| 750 | |
| 751 | /* |
| 752 | * We later require that vma->vm_flags == vm_flags, |
| 753 | * so this tests vma->vm_flags & VM_SPECIAL, too. |
| 754 | */ |
| 755 | if (vm_flags & VM_SPECIAL) |
| 756 | return NULL; |
| 757 | |
| 758 | if (prev) |
| 759 | next = prev->vm_next; |
| 760 | else |
| 761 | next = mm->mmap; |
| 762 | area = next; |
| 763 | if (next && next->vm_end == end) /* cases 6, 7, 8 */ |
| 764 | next = next->vm_next; |
| 765 | |
| 766 | /* |
| 767 | * Can it merge with the predecessor? |
| 768 | */ |
| 769 | if (prev && prev->vm_end == addr && |
| 770 | mpol_equal(vma_policy(prev), policy) && |
| 771 | can_vma_merge_after(prev, vm_flags, |
| 772 | anon_vma, file, pgoff)) { |
| 773 | /* |
| 774 | * OK, it can. Can we now merge in the successor as well? |
| 775 | */ |
| 776 | if (next && end == next->vm_start && |
| 777 | mpol_equal(policy, vma_policy(next)) && |
| 778 | can_vma_merge_before(next, vm_flags, |
| 779 | anon_vma, file, pgoff+pglen) && |
| 780 | is_mergeable_anon_vma(prev->anon_vma, |
| 781 | next->anon_vma)) { |
| 782 | /* cases 1, 6 */ |
| 783 | vma_adjust(prev, prev->vm_start, |
| 784 | next->vm_end, prev->vm_pgoff, NULL); |
| 785 | } else /* cases 2, 5, 7 */ |
| 786 | vma_adjust(prev, prev->vm_start, |
| 787 | end, prev->vm_pgoff, NULL); |
| 788 | return prev; |
| 789 | } |
| 790 | |
| 791 | /* |
| 792 | * Can this new request be merged in front of next? |
| 793 | */ |
| 794 | if (next && end == next->vm_start && |
| 795 | mpol_equal(policy, vma_policy(next)) && |
| 796 | can_vma_merge_before(next, vm_flags, |
| 797 | anon_vma, file, pgoff+pglen)) { |
| 798 | if (prev && addr < prev->vm_end) /* case 4 */ |
| 799 | vma_adjust(prev, prev->vm_start, |
| 800 | addr, prev->vm_pgoff, NULL); |
| 801 | else /* cases 3, 8 */ |
| 802 | vma_adjust(area, addr, next->vm_end, |
| 803 | next->vm_pgoff - pglen, NULL); |
| 804 | return area; |
| 805 | } |
| 806 | |
| 807 | return NULL; |
| 808 | } |
| 809 | |
| 810 | /* |
| 811 | * find_mergeable_anon_vma is used by anon_vma_prepare, to check |
| 812 | * neighbouring vmas for a suitable anon_vma, before it goes off |
| 813 | * to allocate a new anon_vma. It checks because a repetitive |
| 814 | * sequence of mprotects and faults may otherwise lead to distinct |
| 815 | * anon_vmas being allocated, preventing vma merge in subsequent |
| 816 | * mprotect. |
| 817 | */ |
| 818 | struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) |
| 819 | { |
| 820 | struct vm_area_struct *near; |
| 821 | unsigned long vm_flags; |
| 822 | |
| 823 | near = vma->vm_next; |
| 824 | if (!near) |
| 825 | goto try_prev; |
| 826 | |
| 827 | /* |
| 828 | * Since only mprotect tries to remerge vmas, match flags |
| 829 | * which might be mprotected into each other later on. |
| 830 | * Neither mlock nor madvise tries to remerge at present, |
| 831 | * so leave their flags as obstructing a merge. |
| 832 | */ |
| 833 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); |
| 834 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); |
| 835 | |
| 836 | if (near->anon_vma && vma->vm_end == near->vm_start && |
| 837 | mpol_equal(vma_policy(vma), vma_policy(near)) && |
| 838 | can_vma_merge_before(near, vm_flags, |
| 839 | NULL, vma->vm_file, vma->vm_pgoff + |
| 840 | ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))) |
| 841 | return near->anon_vma; |
| 842 | try_prev: |
| 843 | /* |
| 844 | * It is potentially slow to have to call find_vma_prev here. |
| 845 | * But it's only on the first write fault on the vma, not |
| 846 | * every time, and we could devise a way to avoid it later |
| 847 | * (e.g. stash info in next's anon_vma_node when assigning |
| 848 | * an anon_vma, or when trying vma_merge). Another time. |
| 849 | */ |
Eric Sesterhenn | 46a350e | 2006-04-01 01:23:29 +0200 | [diff] [blame] | 850 | BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | if (!near) |
| 852 | goto none; |
| 853 | |
| 854 | vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC); |
| 855 | vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC); |
| 856 | |
| 857 | if (near->anon_vma && near->vm_end == vma->vm_start && |
| 858 | mpol_equal(vma_policy(near), vma_policy(vma)) && |
| 859 | can_vma_merge_after(near, vm_flags, |
| 860 | NULL, vma->vm_file, vma->vm_pgoff)) |
| 861 | return near->anon_vma; |
| 862 | none: |
| 863 | /* |
| 864 | * There's no absolute need to look only at touching neighbours: |
| 865 | * we could search further afield for "compatible" anon_vmas. |
| 866 | * But it would probably just be a waste of time searching, |
| 867 | * or lead to too many vmas hanging off the same anon_vma. |
| 868 | * We're trying to allow mprotect remerging later on, |
| 869 | * not trying to minimize memory used for anon_vmas. |
| 870 | */ |
| 871 | return NULL; |
| 872 | } |
| 873 | |
| 874 | #ifdef CONFIG_PROC_FS |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 875 | void vm_stat_account(struct mm_struct *mm, unsigned long flags, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | struct file *file, long pages) |
| 877 | { |
| 878 | const unsigned long stack_flags |
| 879 | = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); |
| 880 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 881 | if (file) { |
| 882 | mm->shared_vm += pages; |
| 883 | if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) |
| 884 | mm->exec_vm += pages; |
| 885 | } else if (flags & stack_flags) |
| 886 | mm->stack_vm += pages; |
| 887 | if (flags & (VM_RESERVED|VM_IO)) |
| 888 | mm->reserved_vm += pages; |
| 889 | } |
| 890 | #endif /* CONFIG_PROC_FS */ |
| 891 | |
| 892 | /* |
| 893 | * The caller must hold down_write(current->mm->mmap_sem). |
| 894 | */ |
| 895 | |
| 896 | unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, |
| 897 | unsigned long len, unsigned long prot, |
| 898 | unsigned long flags, unsigned long pgoff) |
| 899 | { |
| 900 | struct mm_struct * mm = current->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | struct inode *inode; |
| 902 | unsigned int vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | int accountable = 1; |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 905 | unsigned long reqprot = prot; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | /* |
| 908 | * Does the application expect PROT_READ to imply PROT_EXEC? |
| 909 | * |
| 910 | * (the exception is when the underlying filesystem is noexec |
| 911 | * mounted, in which case we dont add PROT_EXEC.) |
| 912 | */ |
| 913 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 914 | if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | prot |= PROT_EXEC; |
| 916 | |
| 917 | if (!len) |
| 918 | return -EINVAL; |
| 919 | |
Eric Paris | 7cd9414 | 2007-11-26 18:47:40 -0500 | [diff] [blame] | 920 | if (!(flags & MAP_FIXED)) |
| 921 | addr = round_hint_to_min(addr); |
| 922 | |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 923 | error = arch_mmap_check(addr, len, flags); |
| 924 | if (error) |
| 925 | return error; |
| 926 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 927 | /* Careful about overflows.. */ |
| 928 | len = PAGE_ALIGN(len); |
| 929 | if (!len || len > TASK_SIZE) |
| 930 | return -ENOMEM; |
| 931 | |
| 932 | /* offset overflow? */ |
| 933 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| 934 | return -EOVERFLOW; |
| 935 | |
| 936 | /* Too many mappings? */ |
| 937 | if (mm->map_count > sysctl_max_map_count) |
| 938 | return -ENOMEM; |
| 939 | |
| 940 | /* Obtain the address to map to. we verify (or select) it and ensure |
| 941 | * that it represents a valid section of the address space. |
| 942 | */ |
| 943 | addr = get_unmapped_area(file, addr, len, pgoff, flags); |
| 944 | if (addr & ~PAGE_MASK) |
| 945 | return addr; |
| 946 | |
| 947 | /* Do simple checking here so the lower-level routines won't have |
| 948 | * to. we assume access permissions have been handled by the open |
| 949 | * of the memory object, so we don't do any here. |
| 950 | */ |
| 951 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | |
| 952 | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| 953 | |
| 954 | if (flags & MAP_LOCKED) { |
| 955 | if (!can_do_mlock()) |
| 956 | return -EPERM; |
| 957 | vm_flags |= VM_LOCKED; |
| 958 | } |
| 959 | /* mlock MCL_FUTURE? */ |
| 960 | if (vm_flags & VM_LOCKED) { |
| 961 | unsigned long locked, lock_limit; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 962 | locked = len >> PAGE_SHIFT; |
| 963 | locked += mm->locked_vm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 964 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 965 | lock_limit >>= PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
| 967 | return -EAGAIN; |
| 968 | } |
| 969 | |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 970 | inode = file ? file->f_path.dentry->d_inode : NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | |
| 972 | if (file) { |
| 973 | switch (flags & MAP_TYPE) { |
| 974 | case MAP_SHARED: |
| 975 | if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) |
| 976 | return -EACCES; |
| 977 | |
| 978 | /* |
| 979 | * Make sure we don't allow writing to an append-only |
| 980 | * file.. |
| 981 | */ |
| 982 | if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) |
| 983 | return -EACCES; |
| 984 | |
| 985 | /* |
| 986 | * Make sure there are no mandatory locks on the file. |
| 987 | */ |
| 988 | if (locks_verify_locked(inode)) |
| 989 | return -EAGAIN; |
| 990 | |
| 991 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
| 992 | if (!(file->f_mode & FMODE_WRITE)) |
| 993 | vm_flags &= ~(VM_MAYWRITE | VM_SHARED); |
| 994 | |
| 995 | /* fall through */ |
| 996 | case MAP_PRIVATE: |
| 997 | if (!(file->f_mode & FMODE_READ)) |
| 998 | return -EACCES; |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 999 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
Linus Torvalds | 80c5606 | 2006-10-15 14:09:55 -0700 | [diff] [blame] | 1000 | if (vm_flags & VM_EXEC) |
| 1001 | return -EPERM; |
| 1002 | vm_flags &= ~VM_MAYEXEC; |
| 1003 | } |
| 1004 | if (is_file_hugepages(file)) |
| 1005 | accountable = 0; |
| 1006 | |
| 1007 | if (!file->f_op || !file->f_op->mmap) |
| 1008 | return -ENODEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1009 | break; |
| 1010 | |
| 1011 | default: |
| 1012 | return -EINVAL; |
| 1013 | } |
| 1014 | } else { |
| 1015 | switch (flags & MAP_TYPE) { |
| 1016 | case MAP_SHARED: |
| 1017 | vm_flags |= VM_SHARED | VM_MAYSHARE; |
| 1018 | break; |
| 1019 | case MAP_PRIVATE: |
| 1020 | /* |
| 1021 | * Set pgoff according to addr for anon_vma. |
| 1022 | */ |
| 1023 | pgoff = addr >> PAGE_SHIFT; |
| 1024 | break; |
| 1025 | default: |
| 1026 | return -EINVAL; |
| 1027 | } |
| 1028 | } |
| 1029 | |
Eric Paris | ed03218 | 2007-06-28 15:55:21 -0400 | [diff] [blame] | 1030 | error = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1031 | if (error) |
| 1032 | return error; |
Eric Paris | ed03218 | 2007-06-28 15:55:21 -0400 | [diff] [blame] | 1033 | |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 1034 | return mmap_region(file, addr, len, flags, vm_flags, pgoff, |
| 1035 | accountable); |
| 1036 | } |
| 1037 | EXPORT_SYMBOL(do_mmap_pgoff); |
| 1038 | |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1039 | /* |
| 1040 | * Some shared mappigns will want the pages marked read-only |
| 1041 | * to track write events. If so, we'll downgrade vm_page_prot |
| 1042 | * to the private version (using protection_map[] without the |
| 1043 | * VM_SHARED bit). |
| 1044 | */ |
| 1045 | int vma_wants_writenotify(struct vm_area_struct *vma) |
| 1046 | { |
| 1047 | unsigned int vm_flags = vma->vm_flags; |
| 1048 | |
| 1049 | /* If it was private or non-writable, the write bit is already clear */ |
| 1050 | if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) |
| 1051 | return 0; |
| 1052 | |
| 1053 | /* The backer wishes to know when pages are first written to? */ |
| 1054 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) |
| 1055 | return 1; |
| 1056 | |
| 1057 | /* The open routine did something to the protections already? */ |
| 1058 | if (pgprot_val(vma->vm_page_prot) != |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 1059 | pgprot_val(vm_get_page_prot(vm_flags))) |
Alexey Dobriyan | 4e950f6 | 2007-07-30 02:36:13 +0400 | [diff] [blame] | 1060 | return 0; |
| 1061 | |
| 1062 | /* Specialty mapping? */ |
| 1063 | if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) |
| 1064 | return 0; |
| 1065 | |
| 1066 | /* Can the mapping track the dirty pages? */ |
| 1067 | return vma->vm_file && vma->vm_file->f_mapping && |
| 1068 | mapping_cap_account_dirty(vma->vm_file->f_mapping); |
| 1069 | } |
| 1070 | |
| 1071 | |
Miklos Szeredi | 0165ab4 | 2007-07-15 23:38:26 -0700 | [diff] [blame] | 1072 | unsigned long mmap_region(struct file *file, unsigned long addr, |
| 1073 | unsigned long len, unsigned long flags, |
| 1074 | unsigned int vm_flags, unsigned long pgoff, |
| 1075 | int accountable) |
| 1076 | { |
| 1077 | struct mm_struct *mm = current->mm; |
| 1078 | struct vm_area_struct *vma, *prev; |
| 1079 | int correct_wcount = 0; |
| 1080 | int error; |
| 1081 | struct rb_node **rb_link, *rb_parent; |
| 1082 | unsigned long charged = 0; |
| 1083 | struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; |
| 1084 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | /* Clear old maps */ |
| 1086 | error = -ENOMEM; |
| 1087 | munmap_back: |
| 1088 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
| 1089 | if (vma && vma->vm_start < addr + len) { |
| 1090 | if (do_munmap(mm, addr, len)) |
| 1091 | return -ENOMEM; |
| 1092 | goto munmap_back; |
| 1093 | } |
| 1094 | |
| 1095 | /* Check against address space limit. */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 1096 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | return -ENOMEM; |
| 1098 | |
| 1099 | if (accountable && (!(flags & MAP_NORESERVE) || |
| 1100 | sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { |
| 1101 | if (vm_flags & VM_SHARED) { |
| 1102 | /* Check memory availability in shmem_file_setup? */ |
| 1103 | vm_flags |= VM_ACCOUNT; |
| 1104 | } else if (vm_flags & VM_WRITE) { |
| 1105 | /* |
| 1106 | * Private writable mapping: check memory availability |
| 1107 | */ |
| 1108 | charged = len >> PAGE_SHIFT; |
| 1109 | if (security_vm_enough_memory(charged)) |
| 1110 | return -ENOMEM; |
| 1111 | vm_flags |= VM_ACCOUNT; |
| 1112 | } |
| 1113 | } |
| 1114 | |
| 1115 | /* |
| 1116 | * Can we just expand an old private anonymous mapping? |
| 1117 | * The VM_SHARED test is necessary because shmem_zero_setup |
| 1118 | * will create the file object for a shared anonymous map below. |
| 1119 | */ |
| 1120 | if (!file && !(vm_flags & VM_SHARED) && |
| 1121 | vma_merge(mm, prev, addr, addr + len, vm_flags, |
| 1122 | NULL, NULL, pgoff, NULL)) |
| 1123 | goto out; |
| 1124 | |
| 1125 | /* |
| 1126 | * Determine the object being mapped and call the appropriate |
| 1127 | * specific mapper. the address has already been validated, but |
| 1128 | * not unmapped, but the maps are removed from the list. |
| 1129 | */ |
Pekka Enberg | c5e3b83 | 2006-03-25 03:06:43 -0800 | [diff] [blame] | 1130 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1131 | if (!vma) { |
| 1132 | error = -ENOMEM; |
| 1133 | goto unacct_error; |
| 1134 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | |
| 1136 | vma->vm_mm = mm; |
| 1137 | vma->vm_start = addr; |
| 1138 | vma->vm_end = addr + len; |
| 1139 | vma->vm_flags = vm_flags; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 1140 | vma->vm_page_prot = vm_get_page_prot(vm_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | vma->vm_pgoff = pgoff; |
| 1142 | |
| 1143 | if (file) { |
| 1144 | error = -EINVAL; |
| 1145 | if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) |
| 1146 | goto free_vma; |
| 1147 | if (vm_flags & VM_DENYWRITE) { |
| 1148 | error = deny_write_access(file); |
| 1149 | if (error) |
| 1150 | goto free_vma; |
| 1151 | correct_wcount = 1; |
| 1152 | } |
| 1153 | vma->vm_file = file; |
| 1154 | get_file(file); |
| 1155 | error = file->f_op->mmap(file, vma); |
| 1156 | if (error) |
| 1157 | goto unmap_and_free_vma; |
| 1158 | } else if (vm_flags & VM_SHARED) { |
| 1159 | error = shmem_zero_setup(vma); |
| 1160 | if (error) |
| 1161 | goto free_vma; |
| 1162 | } |
| 1163 | |
| 1164 | /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform |
| 1165 | * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) |
| 1166 | * that memory reservation must be checked; but that reservation |
| 1167 | * belongs to shared memory object, not to vma: so now clear it. |
| 1168 | */ |
| 1169 | if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) |
| 1170 | vma->vm_flags &= ~VM_ACCOUNT; |
| 1171 | |
| 1172 | /* Can addr have changed?? |
| 1173 | * |
| 1174 | * Answer: Yes, several device drivers can do it in their |
| 1175 | * f_op->mmap method. -DaveM |
| 1176 | */ |
| 1177 | addr = vma->vm_start; |
| 1178 | pgoff = vma->vm_pgoff; |
| 1179 | vm_flags = vma->vm_flags; |
| 1180 | |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1181 | if (vma_wants_writenotify(vma)) |
Hugh Dickins | 1ddd439 | 2007-10-22 20:45:12 -0700 | [diff] [blame] | 1182 | vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1183 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | if (!file || !vma_merge(mm, prev, addr, vma->vm_end, |
| 1185 | vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { |
| 1186 | file = vma->vm_file; |
| 1187 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 1188 | if (correct_wcount) |
| 1189 | atomic_inc(&inode->i_writecount); |
| 1190 | } else { |
| 1191 | if (file) { |
| 1192 | if (correct_wcount) |
| 1193 | atomic_inc(&inode->i_writecount); |
| 1194 | fput(file); |
| 1195 | } |
| 1196 | mpol_free(vma_policy(vma)); |
| 1197 | kmem_cache_free(vm_area_cachep, vma); |
| 1198 | } |
| 1199 | out: |
| 1200 | mm->total_vm += len >> PAGE_SHIFT; |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1201 | vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1202 | if (vm_flags & VM_LOCKED) { |
| 1203 | mm->locked_vm += len >> PAGE_SHIFT; |
| 1204 | make_pages_present(addr, addr + len); |
| 1205 | } |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1206 | if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) |
| 1207 | make_pages_present(addr, addr + len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1208 | return addr; |
| 1209 | |
| 1210 | unmap_and_free_vma: |
| 1211 | if (correct_wcount) |
| 1212 | atomic_inc(&inode->i_writecount); |
| 1213 | vma->vm_file = NULL; |
| 1214 | fput(file); |
| 1215 | |
| 1216 | /* Undo any partial mapping done by a device driver. */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1217 | unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); |
| 1218 | charged = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1219 | free_vma: |
| 1220 | kmem_cache_free(vm_area_cachep, vma); |
| 1221 | unacct_error: |
| 1222 | if (charged) |
| 1223 | vm_unacct_memory(charged); |
| 1224 | return error; |
| 1225 | } |
| 1226 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1227 | /* Get an address range which is currently unmapped. |
| 1228 | * For shmat() with addr=0. |
| 1229 | * |
| 1230 | * Ugly calling convention alert: |
| 1231 | * Return value with the low bits set means error value, |
| 1232 | * ie |
| 1233 | * if (ret & ~PAGE_MASK) |
| 1234 | * error = ret; |
| 1235 | * |
| 1236 | * This function "knows" that -ENOMEM has the bits set. |
| 1237 | */ |
| 1238 | #ifndef HAVE_ARCH_UNMAPPED_AREA |
| 1239 | unsigned long |
| 1240 | arch_get_unmapped_area(struct file *filp, unsigned long addr, |
| 1241 | unsigned long len, unsigned long pgoff, unsigned long flags) |
| 1242 | { |
| 1243 | struct mm_struct *mm = current->mm; |
| 1244 | struct vm_area_struct *vma; |
| 1245 | unsigned long start_addr; |
| 1246 | |
| 1247 | if (len > TASK_SIZE) |
| 1248 | return -ENOMEM; |
| 1249 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1250 | if (flags & MAP_FIXED) |
| 1251 | return addr; |
| 1252 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | if (addr) { |
| 1254 | addr = PAGE_ALIGN(addr); |
| 1255 | vma = find_vma(mm, addr); |
| 1256 | if (TASK_SIZE - len >= addr && |
| 1257 | (!vma || addr + len <= vma->vm_start)) |
| 1258 | return addr; |
| 1259 | } |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1260 | if (len > mm->cached_hole_size) { |
| 1261 | start_addr = addr = mm->free_area_cache; |
| 1262 | } else { |
| 1263 | start_addr = addr = TASK_UNMAPPED_BASE; |
| 1264 | mm->cached_hole_size = 0; |
| 1265 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1266 | |
| 1267 | full_search: |
| 1268 | for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { |
| 1269 | /* At this point: (!vma || addr < vma->vm_end). */ |
| 1270 | if (TASK_SIZE - len < addr) { |
| 1271 | /* |
| 1272 | * Start a new search - just in case we missed |
| 1273 | * some holes. |
| 1274 | */ |
| 1275 | if (start_addr != TASK_UNMAPPED_BASE) { |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1276 | addr = TASK_UNMAPPED_BASE; |
| 1277 | start_addr = addr; |
| 1278 | mm->cached_hole_size = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1279 | goto full_search; |
| 1280 | } |
| 1281 | return -ENOMEM; |
| 1282 | } |
| 1283 | if (!vma || addr + len <= vma->vm_start) { |
| 1284 | /* |
| 1285 | * Remember the place where we stopped the search: |
| 1286 | */ |
| 1287 | mm->free_area_cache = addr + len; |
| 1288 | return addr; |
| 1289 | } |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1290 | if (addr + mm->cached_hole_size < vma->vm_start) |
| 1291 | mm->cached_hole_size = vma->vm_start - addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1292 | addr = vma->vm_end; |
| 1293 | } |
| 1294 | } |
| 1295 | #endif |
| 1296 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1297 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | { |
| 1299 | /* |
| 1300 | * Is this a new hole at the lowest possible address? |
| 1301 | */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1302 | if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { |
| 1303 | mm->free_area_cache = addr; |
| 1304 | mm->cached_hole_size = ~0UL; |
| 1305 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1306 | } |
| 1307 | |
| 1308 | /* |
| 1309 | * This mmap-allocator allocates new areas top-down from below the |
| 1310 | * stack's low limit (the base): |
| 1311 | */ |
| 1312 | #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN |
| 1313 | unsigned long |
| 1314 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, |
| 1315 | const unsigned long len, const unsigned long pgoff, |
| 1316 | const unsigned long flags) |
| 1317 | { |
| 1318 | struct vm_area_struct *vma; |
| 1319 | struct mm_struct *mm = current->mm; |
| 1320 | unsigned long addr = addr0; |
| 1321 | |
| 1322 | /* requested length too big for entire address space */ |
| 1323 | if (len > TASK_SIZE) |
| 1324 | return -ENOMEM; |
| 1325 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1326 | if (flags & MAP_FIXED) |
| 1327 | return addr; |
| 1328 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | /* requesting a specific address */ |
| 1330 | if (addr) { |
| 1331 | addr = PAGE_ALIGN(addr); |
| 1332 | vma = find_vma(mm, addr); |
| 1333 | if (TASK_SIZE - len >= addr && |
| 1334 | (!vma || addr + len <= vma->vm_start)) |
| 1335 | return addr; |
| 1336 | } |
| 1337 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1338 | /* check if free_area_cache is useful for us */ |
| 1339 | if (len <= mm->cached_hole_size) { |
| 1340 | mm->cached_hole_size = 0; |
| 1341 | mm->free_area_cache = mm->mmap_base; |
| 1342 | } |
| 1343 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | /* either no address requested or can't fit in requested address hole */ |
| 1345 | addr = mm->free_area_cache; |
| 1346 | |
| 1347 | /* make sure it can fit in the remaining address space */ |
Linus Torvalds | 49a4387 | 2005-05-18 15:39:33 -0700 | [diff] [blame] | 1348 | if (addr > len) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | vma = find_vma(mm, addr-len); |
| 1350 | if (!vma || addr <= vma->vm_start) |
| 1351 | /* remember the address as a hint for next time */ |
| 1352 | return (mm->free_area_cache = addr-len); |
| 1353 | } |
| 1354 | |
Chris Wright | 73219d1 | 2005-06-21 17:14:52 -0700 | [diff] [blame] | 1355 | if (mm->mmap_base < len) |
| 1356 | goto bottomup; |
| 1357 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1358 | addr = mm->mmap_base-len; |
| 1359 | |
| 1360 | do { |
| 1361 | /* |
| 1362 | * Lookup failure means no vma is above this address, |
| 1363 | * else if new region fits below vma->vm_start, |
| 1364 | * return with success: |
| 1365 | */ |
| 1366 | vma = find_vma(mm, addr); |
| 1367 | if (!vma || addr+len <= vma->vm_start) |
| 1368 | /* remember the address as a hint for next time */ |
| 1369 | return (mm->free_area_cache = addr); |
| 1370 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1371 | /* remember the largest hole we saw so far */ |
| 1372 | if (addr + mm->cached_hole_size < vma->vm_start) |
| 1373 | mm->cached_hole_size = vma->vm_start - addr; |
| 1374 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1375 | /* try just below the current vma->vm_start */ |
| 1376 | addr = vma->vm_start-len; |
Linus Torvalds | 49a4387 | 2005-05-18 15:39:33 -0700 | [diff] [blame] | 1377 | } while (len < vma->vm_start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | |
Chris Wright | 73219d1 | 2005-06-21 17:14:52 -0700 | [diff] [blame] | 1379 | bottomup: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1380 | /* |
| 1381 | * A failed mmap() very likely causes application failure, |
| 1382 | * so fall back to the bottom-up function here. This scenario |
| 1383 | * can happen with large stack limits and large mmap() |
| 1384 | * allocations. |
| 1385 | */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1386 | mm->cached_hole_size = ~0UL; |
| 1387 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1388 | addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); |
| 1389 | /* |
| 1390 | * Restore the topdown base: |
| 1391 | */ |
| 1392 | mm->free_area_cache = mm->mmap_base; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1393 | mm->cached_hole_size = ~0UL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1394 | |
| 1395 | return addr; |
| 1396 | } |
| 1397 | #endif |
| 1398 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1399 | void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1400 | { |
| 1401 | /* |
| 1402 | * Is this a new hole at the highest possible address? |
| 1403 | */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1404 | if (addr > mm->free_area_cache) |
| 1405 | mm->free_area_cache = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1406 | |
| 1407 | /* dont allow allocations above current base */ |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1408 | if (mm->free_area_cache > mm->mmap_base) |
| 1409 | mm->free_area_cache = mm->mmap_base; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1410 | } |
| 1411 | |
| 1412 | unsigned long |
| 1413 | get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, |
| 1414 | unsigned long pgoff, unsigned long flags) |
| 1415 | { |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1416 | unsigned long (*get_area)(struct file *, unsigned long, |
| 1417 | unsigned long, unsigned long, unsigned long); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1419 | get_area = current->mm->get_unmapped_area; |
| 1420 | if (file && file->f_op && file->f_op->get_unmapped_area) |
| 1421 | get_area = file->f_op->get_unmapped_area; |
| 1422 | addr = get_area(file, addr, len, pgoff, flags); |
| 1423 | if (IS_ERR_VALUE(addr)) |
| 1424 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1425 | |
Linus Torvalds | 07ab67c | 2005-05-19 22:43:37 -0700 | [diff] [blame] | 1426 | if (addr > TASK_SIZE - len) |
| 1427 | return -ENOMEM; |
| 1428 | if (addr & ~PAGE_MASK) |
| 1429 | return -EINVAL; |
Benjamin Herrenschmidt | 06abdfb | 2007-05-06 14:50:13 -0700 | [diff] [blame] | 1430 | |
Martin Schwidefsky | 08e7d9b | 2008-02-04 22:29:16 -0800 | [diff] [blame] | 1431 | return arch_rebalance_pgtables(addr, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1432 | } |
| 1433 | |
| 1434 | EXPORT_SYMBOL(get_unmapped_area); |
| 1435 | |
| 1436 | /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ |
| 1437 | struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) |
| 1438 | { |
| 1439 | struct vm_area_struct *vma = NULL; |
| 1440 | |
| 1441 | if (mm) { |
| 1442 | /* Check the cache first. */ |
| 1443 | /* (Cache hit rate is typically around 35%.) */ |
| 1444 | vma = mm->mmap_cache; |
| 1445 | if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { |
| 1446 | struct rb_node * rb_node; |
| 1447 | |
| 1448 | rb_node = mm->mm_rb.rb_node; |
| 1449 | vma = NULL; |
| 1450 | |
| 1451 | while (rb_node) { |
| 1452 | struct vm_area_struct * vma_tmp; |
| 1453 | |
| 1454 | vma_tmp = rb_entry(rb_node, |
| 1455 | struct vm_area_struct, vm_rb); |
| 1456 | |
| 1457 | if (vma_tmp->vm_end > addr) { |
| 1458 | vma = vma_tmp; |
| 1459 | if (vma_tmp->vm_start <= addr) |
| 1460 | break; |
| 1461 | rb_node = rb_node->rb_left; |
| 1462 | } else |
| 1463 | rb_node = rb_node->rb_right; |
| 1464 | } |
| 1465 | if (vma) |
| 1466 | mm->mmap_cache = vma; |
| 1467 | } |
| 1468 | } |
| 1469 | return vma; |
| 1470 | } |
| 1471 | |
| 1472 | EXPORT_SYMBOL(find_vma); |
| 1473 | |
| 1474 | /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */ |
| 1475 | struct vm_area_struct * |
| 1476 | find_vma_prev(struct mm_struct *mm, unsigned long addr, |
| 1477 | struct vm_area_struct **pprev) |
| 1478 | { |
| 1479 | struct vm_area_struct *vma = NULL, *prev = NULL; |
| 1480 | struct rb_node * rb_node; |
| 1481 | if (!mm) |
| 1482 | goto out; |
| 1483 | |
| 1484 | /* Guard against addr being lower than the first VMA */ |
| 1485 | vma = mm->mmap; |
| 1486 | |
| 1487 | /* Go through the RB tree quickly. */ |
| 1488 | rb_node = mm->mm_rb.rb_node; |
| 1489 | |
| 1490 | while (rb_node) { |
| 1491 | struct vm_area_struct *vma_tmp; |
| 1492 | vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); |
| 1493 | |
| 1494 | if (addr < vma_tmp->vm_end) { |
| 1495 | rb_node = rb_node->rb_left; |
| 1496 | } else { |
| 1497 | prev = vma_tmp; |
| 1498 | if (!prev->vm_next || (addr < prev->vm_next->vm_end)) |
| 1499 | break; |
| 1500 | rb_node = rb_node->rb_right; |
| 1501 | } |
| 1502 | } |
| 1503 | |
| 1504 | out: |
| 1505 | *pprev = prev; |
| 1506 | return prev ? prev->vm_next : vma; |
| 1507 | } |
| 1508 | |
| 1509 | /* |
| 1510 | * Verify that the stack growth is acceptable and |
| 1511 | * update accounting. This is shared with both the |
| 1512 | * grow-up and grow-down cases. |
| 1513 | */ |
| 1514 | static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) |
| 1515 | { |
| 1516 | struct mm_struct *mm = vma->vm_mm; |
| 1517 | struct rlimit *rlim = current->signal->rlim; |
Adam Litke | 0d59a01 | 2007-01-30 14:35:39 -0800 | [diff] [blame] | 1518 | unsigned long new_start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1519 | |
| 1520 | /* address space limit tests */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 1521 | if (!may_expand_vm(mm, grow)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1522 | return -ENOMEM; |
| 1523 | |
| 1524 | /* Stack limit test */ |
| 1525 | if (size > rlim[RLIMIT_STACK].rlim_cur) |
| 1526 | return -ENOMEM; |
| 1527 | |
| 1528 | /* mlock limit tests */ |
| 1529 | if (vma->vm_flags & VM_LOCKED) { |
| 1530 | unsigned long locked; |
| 1531 | unsigned long limit; |
| 1532 | locked = mm->locked_vm + grow; |
| 1533 | limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; |
| 1534 | if (locked > limit && !capable(CAP_IPC_LOCK)) |
| 1535 | return -ENOMEM; |
| 1536 | } |
| 1537 | |
Adam Litke | 0d59a01 | 2007-01-30 14:35:39 -0800 | [diff] [blame] | 1538 | /* Check to ensure the stack will not grow into a hugetlb-only region */ |
| 1539 | new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : |
| 1540 | vma->vm_end - size; |
| 1541 | if (is_hugepage_only_range(vma->vm_mm, new_start, size)) |
| 1542 | return -EFAULT; |
| 1543 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1544 | /* |
| 1545 | * Overcommit.. This must be the final test, as it will |
| 1546 | * update security statistics. |
| 1547 | */ |
| 1548 | if (security_vm_enough_memory(grow)) |
| 1549 | return -ENOMEM; |
| 1550 | |
| 1551 | /* Ok, everything looks good - let it rip */ |
| 1552 | mm->total_vm += grow; |
| 1553 | if (vma->vm_flags & VM_LOCKED) |
| 1554 | mm->locked_vm += grow; |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1555 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1556 | return 0; |
| 1557 | } |
| 1558 | |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 1559 | #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1560 | /* |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 1561 | * PA-RISC uses this for its stack; IA64 for its Register Backing Store. |
| 1562 | * vma is the last one with address > vma->vm_end. Have to extend vma. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1563 | */ |
Matthew Wilcox | 9ab8851 | 2005-11-18 16:16:42 -0500 | [diff] [blame] | 1564 | #ifndef CONFIG_IA64 |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 1565 | static inline |
| 1566 | #endif |
| 1567 | int expand_upwards(struct vm_area_struct *vma, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1568 | { |
| 1569 | int error; |
| 1570 | |
| 1571 | if (!(vma->vm_flags & VM_GROWSUP)) |
| 1572 | return -EFAULT; |
| 1573 | |
| 1574 | /* |
| 1575 | * We must make sure the anon_vma is allocated |
| 1576 | * so that the anon_vma locking is not a noop. |
| 1577 | */ |
| 1578 | if (unlikely(anon_vma_prepare(vma))) |
| 1579 | return -ENOMEM; |
| 1580 | anon_vma_lock(vma); |
| 1581 | |
| 1582 | /* |
| 1583 | * vma->vm_start/vm_end cannot change under us because the caller |
| 1584 | * is required to hold the mmap_sem in read mode. We need the |
| 1585 | * anon_vma lock to serialize against concurrent expand_stacks. |
Helge Deller | 06b32f3 | 2006-12-19 19:28:33 +0100 | [diff] [blame] | 1586 | * Also guard against wrapping around to address 0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1587 | */ |
Helge Deller | 06b32f3 | 2006-12-19 19:28:33 +0100 | [diff] [blame] | 1588 | if (address < PAGE_ALIGN(address+4)) |
| 1589 | address = PAGE_ALIGN(address+4); |
| 1590 | else { |
| 1591 | anon_vma_unlock(vma); |
| 1592 | return -ENOMEM; |
| 1593 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1594 | error = 0; |
| 1595 | |
| 1596 | /* Somebody else might have raced and expanded it already */ |
| 1597 | if (address > vma->vm_end) { |
| 1598 | unsigned long size, grow; |
| 1599 | |
| 1600 | size = address - vma->vm_start; |
| 1601 | grow = (address - vma->vm_end) >> PAGE_SHIFT; |
| 1602 | |
| 1603 | error = acct_stack_growth(vma, size, grow); |
| 1604 | if (!error) |
| 1605 | vma->vm_end = address; |
| 1606 | } |
| 1607 | anon_vma_unlock(vma); |
| 1608 | return error; |
| 1609 | } |
Hugh Dickins | 46dea3d | 2005-10-29 18:16:20 -0700 | [diff] [blame] | 1610 | #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ |
| 1611 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1612 | /* |
| 1613 | * vma is the first one with address < vma->vm_start. Have to extend vma. |
| 1614 | */ |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1615 | static inline int expand_downwards(struct vm_area_struct *vma, |
| 1616 | unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1617 | { |
| 1618 | int error; |
| 1619 | |
| 1620 | /* |
| 1621 | * We must make sure the anon_vma is allocated |
| 1622 | * so that the anon_vma locking is not a noop. |
| 1623 | */ |
| 1624 | if (unlikely(anon_vma_prepare(vma))) |
| 1625 | return -ENOMEM; |
Eric Paris | 8869477 | 2007-11-26 18:47:26 -0500 | [diff] [blame] | 1626 | |
| 1627 | address &= PAGE_MASK; |
Richard Knutsson | 88c3f7a | 2007-12-08 12:02:48 +0100 | [diff] [blame] | 1628 | error = security_file_mmap(NULL, 0, 0, 0, address, 1); |
Eric Paris | 8869477 | 2007-11-26 18:47:26 -0500 | [diff] [blame] | 1629 | if (error) |
| 1630 | return error; |
| 1631 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1632 | anon_vma_lock(vma); |
| 1633 | |
| 1634 | /* |
| 1635 | * vma->vm_start/vm_end cannot change under us because the caller |
| 1636 | * is required to hold the mmap_sem in read mode. We need the |
| 1637 | * anon_vma lock to serialize against concurrent expand_stacks. |
| 1638 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1639 | |
| 1640 | /* Somebody else might have raced and expanded it already */ |
| 1641 | if (address < vma->vm_start) { |
| 1642 | unsigned long size, grow; |
| 1643 | |
| 1644 | size = vma->vm_end - address; |
| 1645 | grow = (vma->vm_start - address) >> PAGE_SHIFT; |
| 1646 | |
| 1647 | error = acct_stack_growth(vma, size, grow); |
| 1648 | if (!error) { |
| 1649 | vma->vm_start = address; |
| 1650 | vma->vm_pgoff -= grow; |
| 1651 | } |
| 1652 | } |
| 1653 | anon_vma_unlock(vma); |
| 1654 | return error; |
| 1655 | } |
| 1656 | |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1657 | int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address) |
| 1658 | { |
| 1659 | return expand_downwards(vma, address); |
| 1660 | } |
| 1661 | |
| 1662 | #ifdef CONFIG_STACK_GROWSUP |
| 1663 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| 1664 | { |
| 1665 | return expand_upwards(vma, address); |
| 1666 | } |
| 1667 | |
| 1668 | struct vm_area_struct * |
| 1669 | find_extend_vma(struct mm_struct *mm, unsigned long addr) |
| 1670 | { |
| 1671 | struct vm_area_struct *vma, *prev; |
| 1672 | |
| 1673 | addr &= PAGE_MASK; |
| 1674 | vma = find_vma_prev(mm, addr, &prev); |
| 1675 | if (vma && (vma->vm_start <= addr)) |
| 1676 | return vma; |
| 1677 | if (!prev || expand_stack(prev, addr)) |
| 1678 | return NULL; |
| 1679 | if (prev->vm_flags & VM_LOCKED) |
| 1680 | make_pages_present(addr, prev->vm_end); |
| 1681 | return prev; |
| 1682 | } |
| 1683 | #else |
| 1684 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| 1685 | { |
| 1686 | return expand_downwards(vma, address); |
| 1687 | } |
| 1688 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1689 | struct vm_area_struct * |
| 1690 | find_extend_vma(struct mm_struct * mm, unsigned long addr) |
| 1691 | { |
| 1692 | struct vm_area_struct * vma; |
| 1693 | unsigned long start; |
| 1694 | |
| 1695 | addr &= PAGE_MASK; |
| 1696 | vma = find_vma(mm,addr); |
| 1697 | if (!vma) |
| 1698 | return NULL; |
| 1699 | if (vma->vm_start <= addr) |
| 1700 | return vma; |
| 1701 | if (!(vma->vm_flags & VM_GROWSDOWN)) |
| 1702 | return NULL; |
| 1703 | start = vma->vm_start; |
| 1704 | if (expand_stack(vma, addr)) |
| 1705 | return NULL; |
Ollie Wild | b6a2fea | 2007-07-19 01:48:16 -0700 | [diff] [blame] | 1706 | if (vma->vm_flags & VM_LOCKED) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | make_pages_present(addr, start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1708 | return vma; |
| 1709 | } |
| 1710 | #endif |
| 1711 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1712 | /* |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1713 | * Ok - we have the memory areas we should free on the vma list, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1714 | * so release them, and do the vma updates. |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1715 | * |
| 1716 | * Called with the mm semaphore held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1717 | */ |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1718 | static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1719 | { |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 1720 | /* Update high watermark before we lower total_vm */ |
| 1721 | update_hiwater_vm(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1722 | do { |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1723 | long nrpages = vma_pages(vma); |
| 1724 | |
| 1725 | mm->total_vm -= nrpages; |
| 1726 | if (vma->vm_flags & VM_LOCKED) |
| 1727 | mm->locked_vm -= nrpages; |
| 1728 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 1729 | vma = remove_vma(vma); |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1730 | } while (vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1731 | validate_mm(mm); |
| 1732 | } |
| 1733 | |
| 1734 | /* |
| 1735 | * Get rid of page table information in the indicated region. |
| 1736 | * |
Paolo 'Blaisorblade' Giarrusso | f10df68 | 2005-09-21 09:55:37 -0700 | [diff] [blame] | 1737 | * Called with the mm semaphore held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1738 | */ |
| 1739 | static void unmap_region(struct mm_struct *mm, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1740 | struct vm_area_struct *vma, struct vm_area_struct *prev, |
| 1741 | unsigned long start, unsigned long end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1742 | { |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1743 | struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1744 | struct mmu_gather *tlb; |
| 1745 | unsigned long nr_accounted = 0; |
| 1746 | |
| 1747 | lru_add_drain(); |
| 1748 | tlb = tlb_gather_mmu(mm, 0); |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 1749 | update_hiwater_rss(mm); |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 1750 | unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1751 | vm_unacct_memory(nr_accounted); |
Hugh Dickins | e2cdef8 | 2005-04-19 13:29:19 -0700 | [diff] [blame] | 1752 | free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1753 | next? next->vm_start: 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1754 | tlb_finish_mmu(tlb, start, end); |
| 1755 | } |
| 1756 | |
| 1757 | /* |
| 1758 | * Create a list of vma's touched by the unmap, removing them from the mm's |
| 1759 | * vma list as we go.. |
| 1760 | */ |
| 1761 | static void |
| 1762 | detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1763 | struct vm_area_struct *prev, unsigned long end) |
| 1764 | { |
| 1765 | struct vm_area_struct **insertion_point; |
| 1766 | struct vm_area_struct *tail_vma = NULL; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1767 | unsigned long addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1768 | |
| 1769 | insertion_point = (prev ? &prev->vm_next : &mm->mmap); |
| 1770 | do { |
| 1771 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
| 1772 | mm->map_count--; |
| 1773 | tail_vma = vma; |
| 1774 | vma = vma->vm_next; |
| 1775 | } while (vma && vma->vm_start < end); |
| 1776 | *insertion_point = vma; |
| 1777 | tail_vma->vm_next = NULL; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1778 | if (mm->unmap_area == arch_unmap_area) |
| 1779 | addr = prev ? prev->vm_end : mm->mmap_base; |
| 1780 | else |
| 1781 | addr = vma ? vma->vm_start : mm->mmap_base; |
| 1782 | mm->unmap_area(mm, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1783 | mm->mmap_cache = NULL; /* Kill the cache. */ |
| 1784 | } |
| 1785 | |
| 1786 | /* |
| 1787 | * Split a vma into two pieces at address 'addr', a new vma is allocated |
Michael Opdenacker | 59c5159 | 2007-05-09 08:57:56 +0200 | [diff] [blame] | 1788 | * either for the first part or the tail. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1789 | */ |
| 1790 | int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, |
| 1791 | unsigned long addr, int new_below) |
| 1792 | { |
| 1793 | struct mempolicy *pol; |
| 1794 | struct vm_area_struct *new; |
| 1795 | |
| 1796 | if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) |
| 1797 | return -EINVAL; |
| 1798 | |
| 1799 | if (mm->map_count >= sysctl_max_map_count) |
| 1800 | return -ENOMEM; |
| 1801 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 1802 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1803 | if (!new) |
| 1804 | return -ENOMEM; |
| 1805 | |
| 1806 | /* most fields are the same, copy all, and then fixup */ |
| 1807 | *new = *vma; |
| 1808 | |
| 1809 | if (new_below) |
| 1810 | new->vm_end = addr; |
| 1811 | else { |
| 1812 | new->vm_start = addr; |
| 1813 | new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); |
| 1814 | } |
| 1815 | |
| 1816 | pol = mpol_copy(vma_policy(vma)); |
| 1817 | if (IS_ERR(pol)) { |
| 1818 | kmem_cache_free(vm_area_cachep, new); |
| 1819 | return PTR_ERR(pol); |
| 1820 | } |
| 1821 | vma_set_policy(new, pol); |
| 1822 | |
| 1823 | if (new->vm_file) |
| 1824 | get_file(new->vm_file); |
| 1825 | |
| 1826 | if (new->vm_ops && new->vm_ops->open) |
| 1827 | new->vm_ops->open(new); |
| 1828 | |
| 1829 | if (new_below) |
| 1830 | vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + |
| 1831 | ((addr - new->vm_start) >> PAGE_SHIFT), new); |
| 1832 | else |
| 1833 | vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); |
| 1834 | |
| 1835 | return 0; |
| 1836 | } |
| 1837 | |
| 1838 | /* Munmap is split into 2 main parts -- this part which finds |
| 1839 | * what needs doing, and the areas themselves, which do the |
| 1840 | * work. This now handles partial unmappings. |
| 1841 | * Jeremy Fitzhardinge <jeremy@goop.org> |
| 1842 | */ |
| 1843 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
| 1844 | { |
| 1845 | unsigned long end; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1846 | struct vm_area_struct *vma, *prev, *last; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1847 | |
| 1848 | if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) |
| 1849 | return -EINVAL; |
| 1850 | |
| 1851 | if ((len = PAGE_ALIGN(len)) == 0) |
| 1852 | return -EINVAL; |
| 1853 | |
| 1854 | /* Find the first overlapping VMA */ |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1855 | vma = find_vma_prev(mm, start, &prev); |
| 1856 | if (!vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1857 | return 0; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1858 | /* we have start < vma->vm_end */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1859 | |
| 1860 | /* if it doesn't overlap, we have nothing.. */ |
| 1861 | end = start + len; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1862 | if (vma->vm_start >= end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1863 | return 0; |
| 1864 | |
| 1865 | /* |
| 1866 | * If we need to split any vma, do it now to save pain later. |
| 1867 | * |
| 1868 | * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially |
| 1869 | * unmapped vm_area_struct will remain in use: so lower split_vma |
| 1870 | * places tmp vma above, and higher split_vma places tmp vma below. |
| 1871 | */ |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1872 | if (start > vma->vm_start) { |
| 1873 | int error = split_vma(mm, vma, start, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1874 | if (error) |
| 1875 | return error; |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1876 | prev = vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | } |
| 1878 | |
| 1879 | /* Does it split the last one? */ |
| 1880 | last = find_vma(mm, end); |
| 1881 | if (last && end > last->vm_start) { |
| 1882 | int error = split_vma(mm, last, end, 1); |
| 1883 | if (error) |
| 1884 | return error; |
| 1885 | } |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1886 | vma = prev? prev->vm_next: mm->mmap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1887 | |
| 1888 | /* |
| 1889 | * Remove the vma's, and unmap the actual pages |
| 1890 | */ |
Hugh Dickins | 146425a | 2005-04-19 13:29:18 -0700 | [diff] [blame] | 1891 | detach_vmas_to_be_unmapped(mm, vma, prev, end); |
| 1892 | unmap_region(mm, vma, prev, start, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1893 | |
| 1894 | /* Fix up all other VM information */ |
Hugh Dickins | 2c0b381 | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 1895 | remove_vma_list(mm, vma); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1896 | |
| 1897 | return 0; |
| 1898 | } |
| 1899 | |
| 1900 | EXPORT_SYMBOL(do_munmap); |
| 1901 | |
| 1902 | asmlinkage long sys_munmap(unsigned long addr, size_t len) |
| 1903 | { |
| 1904 | int ret; |
| 1905 | struct mm_struct *mm = current->mm; |
| 1906 | |
| 1907 | profile_munmap(addr); |
| 1908 | |
| 1909 | down_write(&mm->mmap_sem); |
| 1910 | ret = do_munmap(mm, addr, len); |
| 1911 | up_write(&mm->mmap_sem); |
| 1912 | return ret; |
| 1913 | } |
| 1914 | |
| 1915 | static inline void verify_mm_writelocked(struct mm_struct *mm) |
| 1916 | { |
Paul E. McKenney | a241ec6 | 2005-10-30 15:03:12 -0800 | [diff] [blame] | 1917 | #ifdef CONFIG_DEBUG_VM |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1918 | if (unlikely(down_read_trylock(&mm->mmap_sem))) { |
| 1919 | WARN_ON(1); |
| 1920 | up_read(&mm->mmap_sem); |
| 1921 | } |
| 1922 | #endif |
| 1923 | } |
| 1924 | |
| 1925 | /* |
| 1926 | * this is really a simplified "do_mmap". it only handles |
| 1927 | * anonymous maps. eventually we may be able to do some |
| 1928 | * brk-specific accounting here. |
| 1929 | */ |
| 1930 | unsigned long do_brk(unsigned long addr, unsigned long len) |
| 1931 | { |
| 1932 | struct mm_struct * mm = current->mm; |
| 1933 | struct vm_area_struct * vma, * prev; |
| 1934 | unsigned long flags; |
| 1935 | struct rb_node ** rb_link, * rb_parent; |
| 1936 | pgoff_t pgoff = addr >> PAGE_SHIFT; |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 1937 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | |
| 1939 | len = PAGE_ALIGN(len); |
| 1940 | if (!len) |
| 1941 | return addr; |
| 1942 | |
| 1943 | if ((addr + len) > TASK_SIZE || (addr + len) < addr) |
| 1944 | return -EINVAL; |
| 1945 | |
Hugh Dickins | cd2579d | 2006-11-14 13:43:38 +0000 | [diff] [blame] | 1946 | if (is_hugepage_only_range(mm, addr, len)) |
| 1947 | return -EINVAL; |
David Gibson | cb07c9a | 2006-11-14 02:03:38 -0800 | [diff] [blame] | 1948 | |
Richard Knutsson | 88c3f7a | 2007-12-08 12:02:48 +0100 | [diff] [blame] | 1949 | error = security_file_mmap(NULL, 0, 0, 0, addr, 1); |
Eric Paris | 5a211a5 | 2007-12-04 11:06:55 -0500 | [diff] [blame] | 1950 | if (error) |
| 1951 | return error; |
| 1952 | |
Kirill Korotaev | 3a45975 | 2006-09-07 14:17:04 +0400 | [diff] [blame] | 1953 | flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; |
| 1954 | |
| 1955 | error = arch_mmap_check(addr, len, flags); |
| 1956 | if (error) |
| 1957 | return error; |
| 1958 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1959 | /* |
| 1960 | * mlock MCL_FUTURE? |
| 1961 | */ |
| 1962 | if (mm->def_flags & VM_LOCKED) { |
| 1963 | unsigned long locked, lock_limit; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 1964 | locked = len >> PAGE_SHIFT; |
| 1965 | locked += mm->locked_vm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1966 | lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; |
Chris Wright | 93ea1d0 | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 1967 | lock_limit >>= PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1968 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) |
| 1969 | return -EAGAIN; |
| 1970 | } |
| 1971 | |
| 1972 | /* |
| 1973 | * mm->mmap_sem is required to protect against another thread |
| 1974 | * changing the mappings in case we sleep. |
| 1975 | */ |
| 1976 | verify_mm_writelocked(mm); |
| 1977 | |
| 1978 | /* |
| 1979 | * Clear old maps. this also does some error checking for us |
| 1980 | */ |
| 1981 | munmap_back: |
| 1982 | vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
| 1983 | if (vma && vma->vm_start < addr + len) { |
| 1984 | if (do_munmap(mm, addr, len)) |
| 1985 | return -ENOMEM; |
| 1986 | goto munmap_back; |
| 1987 | } |
| 1988 | |
| 1989 | /* Check against address space limits *after* clearing old maps... */ |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 1990 | if (!may_expand_vm(mm, len >> PAGE_SHIFT)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1991 | return -ENOMEM; |
| 1992 | |
| 1993 | if (mm->map_count > sysctl_max_map_count) |
| 1994 | return -ENOMEM; |
| 1995 | |
| 1996 | if (security_vm_enough_memory(len >> PAGE_SHIFT)) |
| 1997 | return -ENOMEM; |
| 1998 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1999 | /* Can we just expand an old private anonymous mapping? */ |
| 2000 | if (vma_merge(mm, prev, addr, addr + len, flags, |
| 2001 | NULL, NULL, pgoff, NULL)) |
| 2002 | goto out; |
| 2003 | |
| 2004 | /* |
| 2005 | * create a vma struct for an anonymous mapping |
| 2006 | */ |
Pekka Enberg | c5e3b83 | 2006-03-25 03:06:43 -0800 | [diff] [blame] | 2007 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | if (!vma) { |
| 2009 | vm_unacct_memory(len >> PAGE_SHIFT); |
| 2010 | return -ENOMEM; |
| 2011 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2012 | |
| 2013 | vma->vm_mm = mm; |
| 2014 | vma->vm_start = addr; |
| 2015 | vma->vm_end = addr + len; |
| 2016 | vma->vm_pgoff = pgoff; |
| 2017 | vma->vm_flags = flags; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 2018 | vma->vm_page_prot = vm_get_page_prot(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2019 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 2020 | out: |
| 2021 | mm->total_vm += len >> PAGE_SHIFT; |
| 2022 | if (flags & VM_LOCKED) { |
| 2023 | mm->locked_vm += len >> PAGE_SHIFT; |
| 2024 | make_pages_present(addr, addr + len); |
| 2025 | } |
| 2026 | return addr; |
| 2027 | } |
| 2028 | |
| 2029 | EXPORT_SYMBOL(do_brk); |
| 2030 | |
| 2031 | /* Release all mmaps. */ |
| 2032 | void exit_mmap(struct mm_struct *mm) |
| 2033 | { |
| 2034 | struct mmu_gather *tlb; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2035 | struct vm_area_struct *vma = mm->mmap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2036 | unsigned long nr_accounted = 0; |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2037 | unsigned long end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2038 | |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 2039 | /* mm's last user has gone, and its about to be pulled down */ |
| 2040 | arch_exit_mmap(mm); |
| 2041 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2042 | lru_add_drain(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | flush_cache_mm(mm); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2044 | tlb = tlb_gather_mmu(mm, 1); |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 2045 | /* Don't update_hiwater_rss(mm) here, do_exit already did */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2046 | /* Use -1 here to ensure all VMAs in the mm are unmapped */ |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 2047 | end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2048 | vm_unacct_memory(nr_accounted); |
Hugh Dickins | e2cdef8 | 2005-04-19 13:29:19 -0700 | [diff] [blame] | 2049 | free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2050 | tlb_finish_mmu(tlb, 0, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2051 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2052 | /* |
Hugh Dickins | 8f4f8c1 | 2005-10-29 18:16:29 -0700 | [diff] [blame] | 2053 | * Walk the list again, actually closing and freeing it, |
| 2054 | * with preemption enabled, without holding any MM locks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2055 | */ |
Hugh Dickins | a8fb561 | 2005-10-29 18:15:57 -0700 | [diff] [blame] | 2056 | while (vma) |
| 2057 | vma = remove_vma(vma); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 2058 | |
Hugh Dickins | e2cdef8 | 2005-04-19 13:29:19 -0700 | [diff] [blame] | 2059 | BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2060 | } |
| 2061 | |
| 2062 | /* Insert vm structure into process list sorted by address |
| 2063 | * and into the inode's i_mmap tree. If vm_file is non-NULL |
| 2064 | * then i_mmap_lock is taken here. |
| 2065 | */ |
| 2066 | int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
| 2067 | { |
| 2068 | struct vm_area_struct * __vma, * prev; |
| 2069 | struct rb_node ** rb_link, * rb_parent; |
| 2070 | |
| 2071 | /* |
| 2072 | * The vm_pgoff of a purely anonymous vma should be irrelevant |
| 2073 | * until its first write fault, when page's anon_vma and index |
| 2074 | * are set. But now set the vm_pgoff it will almost certainly |
| 2075 | * end up with (unless mremap moves it elsewhere before that |
| 2076 | * first wfault), so /proc/pid/maps tells a consistent story. |
| 2077 | * |
| 2078 | * By setting it to reflect the virtual start address of the |
| 2079 | * vma, merges and splits can happen in a seamless way, just |
| 2080 | * using the existing file pgoff checks and manipulations. |
| 2081 | * Similarly in do_mmap_pgoff and in do_brk. |
| 2082 | */ |
| 2083 | if (!vma->vm_file) { |
| 2084 | BUG_ON(vma->anon_vma); |
| 2085 | vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; |
| 2086 | } |
| 2087 | __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); |
| 2088 | if (__vma && __vma->vm_start < vma->vm_end) |
| 2089 | return -ENOMEM; |
Hugh Dickins | 2fd4ef8 | 2005-09-14 06:13:02 +0100 | [diff] [blame] | 2090 | if ((vma->vm_flags & VM_ACCOUNT) && |
Alan Cox | 34b4e4a | 2007-08-22 14:01:28 -0700 | [diff] [blame] | 2091 | security_vm_enough_memory_mm(mm, vma_pages(vma))) |
Hugh Dickins | 2fd4ef8 | 2005-09-14 06:13:02 +0100 | [diff] [blame] | 2092 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2093 | vma_link(mm, vma, prev, rb_link, rb_parent); |
| 2094 | return 0; |
| 2095 | } |
| 2096 | |
| 2097 | /* |
| 2098 | * Copy the vma structure to a new location in the same mm, |
| 2099 | * prior to moving page table entries, to effect an mremap move. |
| 2100 | */ |
| 2101 | struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, |
| 2102 | unsigned long addr, unsigned long len, pgoff_t pgoff) |
| 2103 | { |
| 2104 | struct vm_area_struct *vma = *vmap; |
| 2105 | unsigned long vma_start = vma->vm_start; |
| 2106 | struct mm_struct *mm = vma->vm_mm; |
| 2107 | struct vm_area_struct *new_vma, *prev; |
| 2108 | struct rb_node **rb_link, *rb_parent; |
| 2109 | struct mempolicy *pol; |
| 2110 | |
| 2111 | /* |
| 2112 | * If anonymous vma has not yet been faulted, update new pgoff |
| 2113 | * to match new location, to increase its chance of merging. |
| 2114 | */ |
| 2115 | if (!vma->vm_file && !vma->anon_vma) |
| 2116 | pgoff = addr >> PAGE_SHIFT; |
| 2117 | |
| 2118 | find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); |
| 2119 | new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, |
| 2120 | vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); |
| 2121 | if (new_vma) { |
| 2122 | /* |
| 2123 | * Source vma may have been merged into new_vma |
| 2124 | */ |
| 2125 | if (vma_start >= new_vma->vm_start && |
| 2126 | vma_start < new_vma->vm_end) |
| 2127 | *vmap = new_vma; |
| 2128 | } else { |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 2129 | new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2130 | if (new_vma) { |
| 2131 | *new_vma = *vma; |
| 2132 | pol = mpol_copy(vma_policy(vma)); |
| 2133 | if (IS_ERR(pol)) { |
| 2134 | kmem_cache_free(vm_area_cachep, new_vma); |
| 2135 | return NULL; |
| 2136 | } |
| 2137 | vma_set_policy(new_vma, pol); |
| 2138 | new_vma->vm_start = addr; |
| 2139 | new_vma->vm_end = addr + len; |
| 2140 | new_vma->vm_pgoff = pgoff; |
| 2141 | if (new_vma->vm_file) |
| 2142 | get_file(new_vma->vm_file); |
| 2143 | if (new_vma->vm_ops && new_vma->vm_ops->open) |
| 2144 | new_vma->vm_ops->open(new_vma); |
| 2145 | vma_link(mm, new_vma, prev, rb_link, rb_parent); |
| 2146 | } |
| 2147 | } |
| 2148 | return new_vma; |
| 2149 | } |
akpm@osdl.org | 119f657 | 2005-05-01 08:58:35 -0700 | [diff] [blame] | 2150 | |
| 2151 | /* |
| 2152 | * Return true if the calling process may expand its vm space by the passed |
| 2153 | * number of pages |
| 2154 | */ |
| 2155 | int may_expand_vm(struct mm_struct *mm, unsigned long npages) |
| 2156 | { |
| 2157 | unsigned long cur = mm->total_vm; /* pages */ |
| 2158 | unsigned long lim; |
| 2159 | |
| 2160 | lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; |
| 2161 | |
| 2162 | if (cur + npages > lim) |
| 2163 | return 0; |
| 2164 | return 1; |
| 2165 | } |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2166 | |
| 2167 | |
| 2168 | static struct page *special_mapping_nopage(struct vm_area_struct *vma, |
| 2169 | unsigned long address, int *type) |
| 2170 | { |
| 2171 | struct page **pages; |
| 2172 | |
| 2173 | BUG_ON(address < vma->vm_start || address >= vma->vm_end); |
| 2174 | |
| 2175 | address -= vma->vm_start; |
| 2176 | for (pages = vma->vm_private_data; address > 0 && *pages; ++pages) |
| 2177 | address -= PAGE_SIZE; |
| 2178 | |
| 2179 | if (*pages) { |
| 2180 | struct page *page = *pages; |
| 2181 | get_page(page); |
| 2182 | return page; |
| 2183 | } |
| 2184 | |
| 2185 | return NOPAGE_SIGBUS; |
| 2186 | } |
| 2187 | |
| 2188 | /* |
| 2189 | * Having a close hook prevents vma merging regardless of flags. |
| 2190 | */ |
| 2191 | static void special_mapping_close(struct vm_area_struct *vma) |
| 2192 | { |
| 2193 | } |
| 2194 | |
| 2195 | static struct vm_operations_struct special_mapping_vmops = { |
| 2196 | .close = special_mapping_close, |
| 2197 | .nopage = special_mapping_nopage, |
| 2198 | }; |
| 2199 | |
| 2200 | /* |
| 2201 | * Called with mm->mmap_sem held for writing. |
| 2202 | * Insert a new vma covering the given region, with the given flags. |
| 2203 | * Its pages are supplied by the given array of struct page *. |
| 2204 | * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. |
| 2205 | * The region past the last page supplied will always produce SIGBUS. |
| 2206 | * The array pointer and the pages it points to are assumed to stay alive |
| 2207 | * for as long as this mapping might exist. |
| 2208 | */ |
| 2209 | int install_special_mapping(struct mm_struct *mm, |
| 2210 | unsigned long addr, unsigned long len, |
| 2211 | unsigned long vm_flags, struct page **pages) |
| 2212 | { |
| 2213 | struct vm_area_struct *vma; |
| 2214 | |
| 2215 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
| 2216 | if (unlikely(vma == NULL)) |
| 2217 | return -ENOMEM; |
| 2218 | |
| 2219 | vma->vm_mm = mm; |
| 2220 | vma->vm_start = addr; |
| 2221 | vma->vm_end = addr + len; |
| 2222 | |
Nick Piggin | 2f98735 | 2008-02-02 03:08:53 +0100 | [diff] [blame] | 2223 | vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; |
Coly Li | 3ed75eb | 2007-10-18 23:39:15 -0700 | [diff] [blame] | 2224 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
Roland McGrath | fa5dc22 | 2007-02-08 14:20:41 -0800 | [diff] [blame] | 2225 | |
| 2226 | vma->vm_ops = &special_mapping_vmops; |
| 2227 | vma->vm_private_data = pages; |
| 2228 | |
| 2229 | if (unlikely(insert_vm_struct(mm, vma))) { |
| 2230 | kmem_cache_free(vm_area_cachep, vma); |
| 2231 | return -ENOMEM; |
| 2232 | } |
| 2233 | |
| 2234 | mm->total_vm += len >> PAGE_SHIFT; |
| 2235 | |
| 2236 | return 0; |
| 2237 | } |