Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/nommu.c |
| 3 | * |
| 4 | * Replacement code for mm functions to support CPU's that don't |
| 5 | * have any form of memory management unit (thus no virtual memory). |
| 6 | * |
| 7 | * See Documentation/nommu-mmap.txt |
| 8 | * |
| 9 | * Copyright (c) 2004-2005 David Howells <dhowells@redhat.com> |
| 10 | * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com> |
| 11 | * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> |
| 12 | * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com> |
| 13 | */ |
| 14 | |
| 15 | #include <linux/mm.h> |
| 16 | #include <linux/mman.h> |
| 17 | #include <linux/swap.h> |
| 18 | #include <linux/file.h> |
| 19 | #include <linux/highmem.h> |
| 20 | #include <linux/pagemap.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/vmalloc.h> |
| 23 | #include <linux/ptrace.h> |
| 24 | #include <linux/blkdev.h> |
| 25 | #include <linux/backing-dev.h> |
| 26 | #include <linux/mount.h> |
| 27 | #include <linux/personality.h> |
| 28 | #include <linux/security.h> |
| 29 | #include <linux/syscalls.h> |
| 30 | |
| 31 | #include <asm/uaccess.h> |
| 32 | #include <asm/tlb.h> |
| 33 | #include <asm/tlbflush.h> |
| 34 | |
| 35 | void *high_memory; |
| 36 | struct page *mem_map; |
| 37 | unsigned long max_mapnr; |
| 38 | unsigned long num_physpages; |
| 39 | unsigned long askedalloc, realalloc; |
| 40 | atomic_t vm_committed_space = ATOMIC_INIT(0); |
| 41 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
| 42 | int sysctl_overcommit_ratio = 50; /* default is 50% */ |
| 43 | int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; |
| 44 | int heap_stack_gap = 0; |
| 45 | |
| 46 | EXPORT_SYMBOL(mem_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | EXPORT_SYMBOL(__vm_enough_memory); |
| 48 | |
| 49 | /* list of shareable VMAs */ |
| 50 | struct rb_root nommu_vma_tree = RB_ROOT; |
| 51 | DECLARE_RWSEM(nommu_vma_sem); |
| 52 | |
| 53 | struct vm_operations_struct generic_file_vm_ops = { |
| 54 | }; |
| 55 | |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 56 | EXPORT_SYMBOL(vfree); |
| 57 | EXPORT_SYMBOL(vmalloc_to_page); |
| 58 | EXPORT_SYMBOL(vmalloc_32); |
Luke Yang | 7a9166e | 2006-02-20 18:28:07 -0800 | [diff] [blame] | 59 | EXPORT_SYMBOL(vmap); |
| 60 | EXPORT_SYMBOL(vunmap); |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 61 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | /* |
| 63 | * Handle all mappings that got truncated by a "truncate()" |
| 64 | * system call. |
| 65 | * |
| 66 | * NOTE! We have to be ready to update the memory sharing |
| 67 | * between the file and the memory map for a potential last |
| 68 | * incomplete page. Ugly, but necessary. |
| 69 | */ |
| 70 | int vmtruncate(struct inode *inode, loff_t offset) |
| 71 | { |
| 72 | struct address_space *mapping = inode->i_mapping; |
| 73 | unsigned long limit; |
| 74 | |
| 75 | if (inode->i_size < offset) |
| 76 | goto do_expand; |
| 77 | i_size_write(inode, offset); |
| 78 | |
| 79 | truncate_inode_pages(mapping, offset); |
| 80 | goto out_truncate; |
| 81 | |
| 82 | do_expand: |
| 83 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
| 84 | if (limit != RLIM_INFINITY && offset > limit) |
| 85 | goto out_sig; |
| 86 | if (offset > inode->i_sb->s_maxbytes) |
| 87 | goto out; |
| 88 | i_size_write(inode, offset); |
| 89 | |
| 90 | out_truncate: |
| 91 | if (inode->i_op && inode->i_op->truncate) |
| 92 | inode->i_op->truncate(inode); |
| 93 | return 0; |
| 94 | out_sig: |
| 95 | send_sig(SIGXFSZ, current, 0); |
| 96 | out: |
| 97 | return -EFBIG; |
| 98 | } |
| 99 | |
| 100 | EXPORT_SYMBOL(vmtruncate); |
| 101 | |
| 102 | /* |
| 103 | * Return the total memory allocated for this pointer, not |
| 104 | * just what the caller asked for. |
| 105 | * |
| 106 | * Doesn't have to be accurate, i.e. may have races. |
| 107 | */ |
| 108 | unsigned int kobjsize(const void *objp) |
| 109 | { |
| 110 | struct page *page; |
| 111 | |
| 112 | if (!objp || !((page = virt_to_page(objp)))) |
| 113 | return 0; |
| 114 | |
| 115 | if (PageSlab(page)) |
| 116 | return ksize(objp); |
| 117 | |
| 118 | BUG_ON(page->index < 0); |
| 119 | BUG_ON(page->index >= MAX_ORDER); |
| 120 | |
| 121 | return (PAGE_SIZE << page->index); |
| 122 | } |
| 123 | |
| 124 | /* |
David Howells | 7b4d5b8 | 2006-09-27 01:50:18 -0700 | [diff] [blame] | 125 | * get a list of pages in an address range belonging to the specified process |
| 126 | * and indicate the VMA that covers each page |
| 127 | * - this is potentially dodgy as we may end incrementing the page count of a |
| 128 | * slab page or a secondary page from a compound page |
| 129 | * - don't permit access to VMAs that don't support it, such as I/O mappings |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | */ |
| 131 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
| 132 | unsigned long start, int len, int write, int force, |
| 133 | struct page **pages, struct vm_area_struct **vmas) |
| 134 | { |
Sonic Zhang | 910e46d | 2006-09-27 01:50:17 -0700 | [diff] [blame] | 135 | struct vm_area_struct *vma; |
David Howells | 7b4d5b8 | 2006-09-27 01:50:18 -0700 | [diff] [blame] | 136 | unsigned long vm_flags; |
| 137 | int i; |
| 138 | |
| 139 | /* calculate required read or write permissions. |
| 140 | * - if 'force' is set, we only require the "MAY" flags. |
| 141 | */ |
| 142 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
| 143 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | |
| 145 | for (i = 0; i < len; i++) { |
Sonic Zhang | 910e46d | 2006-09-27 01:50:17 -0700 | [diff] [blame] | 146 | vma = find_vma(mm, start); |
David Howells | 7b4d5b8 | 2006-09-27 01:50:18 -0700 | [diff] [blame] | 147 | if (!vma) |
| 148 | goto finish_or_fault; |
| 149 | |
| 150 | /* protect what we can, including chardevs */ |
| 151 | if (vma->vm_flags & (VM_IO | VM_PFNMAP) || |
| 152 | !(vm_flags & vma->vm_flags)) |
| 153 | goto finish_or_fault; |
Sonic Zhang | 910e46d | 2006-09-27 01:50:17 -0700 | [diff] [blame] | 154 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | if (pages) { |
| 156 | pages[i] = virt_to_page(start); |
| 157 | if (pages[i]) |
| 158 | page_cache_get(pages[i]); |
| 159 | } |
| 160 | if (vmas) |
Sonic Zhang | 910e46d | 2006-09-27 01:50:17 -0700 | [diff] [blame] | 161 | vmas[i] = vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | start += PAGE_SIZE; |
| 163 | } |
David Howells | 7b4d5b8 | 2006-09-27 01:50:18 -0700 | [diff] [blame] | 164 | |
| 165 | return i; |
| 166 | |
| 167 | finish_or_fault: |
| 168 | return i ? : -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | } |
| 170 | |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 171 | EXPORT_SYMBOL(get_user_pages); |
| 172 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | DEFINE_RWLOCK(vmlist_lock); |
| 174 | struct vm_struct *vmlist; |
| 175 | |
| 176 | void vfree(void *addr) |
| 177 | { |
| 178 | kfree(addr); |
| 179 | } |
| 180 | |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 181 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | { |
| 183 | /* |
| 184 | * kmalloc doesn't like __GFP_HIGHMEM for some reason |
| 185 | */ |
Nick Piggin | 8409751 | 2006-03-22 00:08:34 -0800 | [diff] [blame] | 186 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | struct page * vmalloc_to_page(void *addr) |
| 190 | { |
| 191 | return virt_to_page(addr); |
| 192 | } |
| 193 | |
| 194 | unsigned long vmalloc_to_pfn(void *addr) |
| 195 | { |
| 196 | return page_to_pfn(virt_to_page(addr)); |
| 197 | } |
| 198 | |
| 199 | |
| 200 | long vread(char *buf, char *addr, unsigned long count) |
| 201 | { |
| 202 | memcpy(buf, addr, count); |
| 203 | return count; |
| 204 | } |
| 205 | |
| 206 | long vwrite(char *buf, char *addr, unsigned long count) |
| 207 | { |
| 208 | /* Don't allow overflow */ |
| 209 | if ((unsigned long) addr + count < count) |
| 210 | count = -(unsigned long) addr; |
| 211 | |
| 212 | memcpy(addr, buf, count); |
| 213 | return(count); |
| 214 | } |
| 215 | |
| 216 | /* |
| 217 | * vmalloc - allocate virtually continguos memory |
| 218 | * |
| 219 | * @size: allocation size |
| 220 | * |
| 221 | * Allocate enough pages to cover @size from the page level |
| 222 | * allocator and map them into continguos kernel virtual space. |
| 223 | * |
| 224 | * For tight cotrol over page level allocator and protection flags |
| 225 | * use __vmalloc() instead. |
| 226 | */ |
| 227 | void *vmalloc(unsigned long size) |
| 228 | { |
| 229 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); |
| 230 | } |
Andrew Morton | f613888 | 2006-02-28 16:59:18 -0800 | [diff] [blame] | 231 | EXPORT_SYMBOL(vmalloc); |
| 232 | |
| 233 | void *vmalloc_node(unsigned long size, int node) |
| 234 | { |
| 235 | return vmalloc(size); |
| 236 | } |
| 237 | EXPORT_SYMBOL(vmalloc_node); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | |
| 239 | /* |
| 240 | * vmalloc_32 - allocate virtually continguos memory (32bit addressable) |
| 241 | * |
| 242 | * @size: allocation size |
| 243 | * |
| 244 | * Allocate enough 32bit PA addressable pages to cover @size from the |
| 245 | * page level allocator and map them into continguos kernel virtual space. |
| 246 | */ |
| 247 | void *vmalloc_32(unsigned long size) |
| 248 | { |
| 249 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); |
| 250 | } |
| 251 | |
| 252 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) |
| 253 | { |
| 254 | BUG(); |
| 255 | return NULL; |
| 256 | } |
| 257 | |
| 258 | void vunmap(void *addr) |
| 259 | { |
| 260 | BUG(); |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * sys_brk() for the most part doesn't need the global kernel |
| 265 | * lock, except when an application is doing something nasty |
| 266 | * like trying to un-brk an area that has already been mapped |
| 267 | * to a regular file. in this case, the unmapping will need |
| 268 | * to invoke file system routines that need the global lock. |
| 269 | */ |
| 270 | asmlinkage unsigned long sys_brk(unsigned long brk) |
| 271 | { |
| 272 | struct mm_struct *mm = current->mm; |
| 273 | |
| 274 | if (brk < mm->start_brk || brk > mm->context.end_brk) |
| 275 | return mm->brk; |
| 276 | |
| 277 | if (mm->brk == brk) |
| 278 | return mm->brk; |
| 279 | |
| 280 | /* |
| 281 | * Always allow shrinking brk |
| 282 | */ |
| 283 | if (brk <= mm->brk) { |
| 284 | mm->brk = brk; |
| 285 | return brk; |
| 286 | } |
| 287 | |
| 288 | /* |
| 289 | * Ok, looks good - let it rip. |
| 290 | */ |
| 291 | return mm->brk = brk; |
| 292 | } |
| 293 | |
| 294 | #ifdef DEBUG |
| 295 | static void show_process_blocks(void) |
| 296 | { |
| 297 | struct vm_list_struct *vml; |
| 298 | |
| 299 | printk("Process blocks %d:", current->pid); |
| 300 | |
| 301 | for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) { |
| 302 | printk(" %p: %p", vml, vml->vma); |
| 303 | if (vml->vma) |
| 304 | printk(" (%d @%lx #%d)", |
| 305 | kobjsize((void *) vml->vma->vm_start), |
| 306 | vml->vma->vm_start, |
| 307 | atomic_read(&vml->vma->vm_usage)); |
| 308 | printk(vml->next ? " ->" : ".\n"); |
| 309 | } |
| 310 | } |
| 311 | #endif /* DEBUG */ |
| 312 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 313 | /* |
| 314 | * add a VMA into a process's mm_struct in the appropriate place in the list |
| 315 | * - should be called with mm->mmap_sem held writelocked |
| 316 | */ |
| 317 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml) |
| 318 | { |
| 319 | struct vm_list_struct **ppv; |
| 320 | |
| 321 | for (ppv = ¤t->mm->context.vmlist; *ppv; ppv = &(*ppv)->next) |
| 322 | if ((*ppv)->vma->vm_start > vml->vma->vm_start) |
| 323 | break; |
| 324 | |
| 325 | vml->next = *ppv; |
| 326 | *ppv = vml; |
| 327 | } |
| 328 | |
| 329 | /* |
| 330 | * look up the first VMA in which addr resides, NULL if none |
| 331 | * - should be called with mm->mmap_sem at least held readlocked |
| 332 | */ |
| 333 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
| 334 | { |
| 335 | struct vm_list_struct *loop, *vml; |
| 336 | |
| 337 | /* search the vm_start ordered list */ |
| 338 | vml = NULL; |
| 339 | for (loop = mm->context.vmlist; loop; loop = loop->next) { |
| 340 | if (loop->vma->vm_start > addr) |
| 341 | break; |
| 342 | vml = loop; |
| 343 | } |
| 344 | |
| 345 | if (vml && vml->vma->vm_end > addr) |
| 346 | return vml->vma; |
| 347 | |
| 348 | return NULL; |
| 349 | } |
| 350 | EXPORT_SYMBOL(find_vma); |
| 351 | |
| 352 | /* |
David Howells | 930e652 | 2006-09-27 01:50:22 -0700 | [diff] [blame] | 353 | * find a VMA |
| 354 | * - we don't extend stack VMAs under NOMMU conditions |
| 355 | */ |
| 356 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) |
| 357 | { |
| 358 | return find_vma(mm, addr); |
| 359 | } |
| 360 | |
| 361 | /* |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 362 | * look up the first VMA exactly that exactly matches addr |
| 363 | * - should be called with mm->mmap_sem at least held readlocked |
| 364 | */ |
| 365 | static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm, |
| 366 | unsigned long addr) |
| 367 | { |
| 368 | struct vm_list_struct *vml; |
| 369 | |
| 370 | /* search the vm_start ordered list */ |
| 371 | for (vml = mm->context.vmlist; vml; vml = vml->next) { |
| 372 | if (vml->vma->vm_start == addr) |
| 373 | return vml->vma; |
| 374 | if (vml->vma->vm_start > addr) |
| 375 | break; |
| 376 | } |
| 377 | |
| 378 | return NULL; |
| 379 | } |
| 380 | |
| 381 | /* |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 382 | * find a VMA in the global tree |
| 383 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | static inline struct vm_area_struct *find_nommu_vma(unsigned long start) |
| 385 | { |
| 386 | struct vm_area_struct *vma; |
| 387 | struct rb_node *n = nommu_vma_tree.rb_node; |
| 388 | |
| 389 | while (n) { |
| 390 | vma = rb_entry(n, struct vm_area_struct, vm_rb); |
| 391 | |
| 392 | if (start < vma->vm_start) |
| 393 | n = n->rb_left; |
| 394 | else if (start > vma->vm_start) |
| 395 | n = n->rb_right; |
| 396 | else |
| 397 | return vma; |
| 398 | } |
| 399 | |
| 400 | return NULL; |
| 401 | } |
| 402 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 403 | /* |
| 404 | * add a VMA in the global tree |
| 405 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | static void add_nommu_vma(struct vm_area_struct *vma) |
| 407 | { |
| 408 | struct vm_area_struct *pvma; |
| 409 | struct address_space *mapping; |
| 410 | struct rb_node **p = &nommu_vma_tree.rb_node; |
| 411 | struct rb_node *parent = NULL; |
| 412 | |
| 413 | /* add the VMA to the mapping */ |
| 414 | if (vma->vm_file) { |
| 415 | mapping = vma->vm_file->f_mapping; |
| 416 | |
| 417 | flush_dcache_mmap_lock(mapping); |
| 418 | vma_prio_tree_insert(vma, &mapping->i_mmap); |
| 419 | flush_dcache_mmap_unlock(mapping); |
| 420 | } |
| 421 | |
| 422 | /* add the VMA to the master list */ |
| 423 | while (*p) { |
| 424 | parent = *p; |
| 425 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
| 426 | |
| 427 | if (vma->vm_start < pvma->vm_start) { |
| 428 | p = &(*p)->rb_left; |
| 429 | } |
| 430 | else if (vma->vm_start > pvma->vm_start) { |
| 431 | p = &(*p)->rb_right; |
| 432 | } |
| 433 | else { |
| 434 | /* mappings are at the same address - this can only |
| 435 | * happen for shared-mem chardevs and shared file |
| 436 | * mappings backed by ramfs/tmpfs */ |
| 437 | BUG_ON(!(pvma->vm_flags & VM_SHARED)); |
| 438 | |
| 439 | if (vma < pvma) |
| 440 | p = &(*p)->rb_left; |
| 441 | else if (vma > pvma) |
| 442 | p = &(*p)->rb_right; |
| 443 | else |
| 444 | BUG(); |
| 445 | } |
| 446 | } |
| 447 | |
| 448 | rb_link_node(&vma->vm_rb, parent, p); |
| 449 | rb_insert_color(&vma->vm_rb, &nommu_vma_tree); |
| 450 | } |
| 451 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 452 | /* |
| 453 | * delete a VMA from the global list |
| 454 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | static void delete_nommu_vma(struct vm_area_struct *vma) |
| 456 | { |
| 457 | struct address_space *mapping; |
| 458 | |
| 459 | /* remove the VMA from the mapping */ |
| 460 | if (vma->vm_file) { |
| 461 | mapping = vma->vm_file->f_mapping; |
| 462 | |
| 463 | flush_dcache_mmap_lock(mapping); |
| 464 | vma_prio_tree_remove(vma, &mapping->i_mmap); |
| 465 | flush_dcache_mmap_unlock(mapping); |
| 466 | } |
| 467 | |
| 468 | /* remove from the master list */ |
| 469 | rb_erase(&vma->vm_rb, &nommu_vma_tree); |
| 470 | } |
| 471 | |
| 472 | /* |
| 473 | * determine whether a mapping should be permitted and, if so, what sort of |
| 474 | * mapping we're capable of supporting |
| 475 | */ |
| 476 | static int validate_mmap_request(struct file *file, |
| 477 | unsigned long addr, |
| 478 | unsigned long len, |
| 479 | unsigned long prot, |
| 480 | unsigned long flags, |
| 481 | unsigned long pgoff, |
| 482 | unsigned long *_capabilities) |
| 483 | { |
| 484 | unsigned long capabilities; |
| 485 | unsigned long reqprot = prot; |
| 486 | int ret; |
| 487 | |
| 488 | /* do the simple checks first */ |
| 489 | if (flags & MAP_FIXED || addr) { |
| 490 | printk(KERN_DEBUG |
| 491 | "%d: Can't do fixed-address/overlay mmap of RAM\n", |
| 492 | current->pid); |
| 493 | return -EINVAL; |
| 494 | } |
| 495 | |
| 496 | if ((flags & MAP_TYPE) != MAP_PRIVATE && |
| 497 | (flags & MAP_TYPE) != MAP_SHARED) |
| 498 | return -EINVAL; |
| 499 | |
| 500 | if (PAGE_ALIGN(len) == 0) |
| 501 | return addr; |
| 502 | |
| 503 | if (len > TASK_SIZE) |
| 504 | return -EINVAL; |
| 505 | |
| 506 | /* offset overflow? */ |
| 507 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| 508 | return -EINVAL; |
| 509 | |
| 510 | if (file) { |
| 511 | /* validate file mapping requests */ |
| 512 | struct address_space *mapping; |
| 513 | |
| 514 | /* files must support mmap */ |
| 515 | if (!file->f_op || !file->f_op->mmap) |
| 516 | return -ENODEV; |
| 517 | |
| 518 | /* work out if what we've got could possibly be shared |
| 519 | * - we support chardevs that provide their own "memory" |
| 520 | * - we support files/blockdevs that are memory backed |
| 521 | */ |
| 522 | mapping = file->f_mapping; |
| 523 | if (!mapping) |
| 524 | mapping = file->f_dentry->d_inode->i_mapping; |
| 525 | |
| 526 | capabilities = 0; |
| 527 | if (mapping && mapping->backing_dev_info) |
| 528 | capabilities = mapping->backing_dev_info->capabilities; |
| 529 | |
| 530 | if (!capabilities) { |
| 531 | /* no explicit capabilities set, so assume some |
| 532 | * defaults */ |
| 533 | switch (file->f_dentry->d_inode->i_mode & S_IFMT) { |
| 534 | case S_IFREG: |
| 535 | case S_IFBLK: |
| 536 | capabilities = BDI_CAP_MAP_COPY; |
| 537 | break; |
| 538 | |
| 539 | case S_IFCHR: |
| 540 | capabilities = |
| 541 | BDI_CAP_MAP_DIRECT | |
| 542 | BDI_CAP_READ_MAP | |
| 543 | BDI_CAP_WRITE_MAP; |
| 544 | break; |
| 545 | |
| 546 | default: |
| 547 | return -EINVAL; |
| 548 | } |
| 549 | } |
| 550 | |
| 551 | /* eliminate any capabilities that we can't support on this |
| 552 | * device */ |
| 553 | if (!file->f_op->get_unmapped_area) |
| 554 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
| 555 | if (!file->f_op->read) |
| 556 | capabilities &= ~BDI_CAP_MAP_COPY; |
| 557 | |
| 558 | if (flags & MAP_SHARED) { |
| 559 | /* do checks for writing, appending and locking */ |
| 560 | if ((prot & PROT_WRITE) && |
| 561 | !(file->f_mode & FMODE_WRITE)) |
| 562 | return -EACCES; |
| 563 | |
| 564 | if (IS_APPEND(file->f_dentry->d_inode) && |
| 565 | (file->f_mode & FMODE_WRITE)) |
| 566 | return -EACCES; |
| 567 | |
| 568 | if (locks_verify_locked(file->f_dentry->d_inode)) |
| 569 | return -EAGAIN; |
| 570 | |
| 571 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
| 572 | return -ENODEV; |
| 573 | |
| 574 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || |
| 575 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || |
| 576 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) |
| 577 | ) { |
| 578 | printk("MAP_SHARED not completely supported on !MMU\n"); |
| 579 | return -EINVAL; |
| 580 | } |
| 581 | |
| 582 | /* we mustn't privatise shared mappings */ |
| 583 | capabilities &= ~BDI_CAP_MAP_COPY; |
| 584 | } |
| 585 | else { |
| 586 | /* we're going to read the file into private memory we |
| 587 | * allocate */ |
| 588 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
| 589 | return -ENODEV; |
| 590 | |
| 591 | /* we don't permit a private writable mapping to be |
| 592 | * shared with the backing device */ |
| 593 | if (prot & PROT_WRITE) |
| 594 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
| 595 | } |
| 596 | |
| 597 | /* handle executable mappings and implied executable |
| 598 | * mappings */ |
| 599 | if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) { |
| 600 | if (prot & PROT_EXEC) |
| 601 | return -EPERM; |
| 602 | } |
| 603 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
| 604 | /* handle implication of PROT_EXEC by PROT_READ */ |
| 605 | if (current->personality & READ_IMPLIES_EXEC) { |
| 606 | if (capabilities & BDI_CAP_EXEC_MAP) |
| 607 | prot |= PROT_EXEC; |
| 608 | } |
| 609 | } |
| 610 | else if ((prot & PROT_READ) && |
| 611 | (prot & PROT_EXEC) && |
| 612 | !(capabilities & BDI_CAP_EXEC_MAP) |
| 613 | ) { |
| 614 | /* backing file is not executable, try to copy */ |
| 615 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
| 616 | } |
| 617 | } |
| 618 | else { |
| 619 | /* anonymous mappings are always memory backed and can be |
| 620 | * privately mapped |
| 621 | */ |
| 622 | capabilities = BDI_CAP_MAP_COPY; |
| 623 | |
| 624 | /* handle PROT_EXEC implication by PROT_READ */ |
| 625 | if ((prot & PROT_READ) && |
| 626 | (current->personality & READ_IMPLIES_EXEC)) |
| 627 | prot |= PROT_EXEC; |
| 628 | } |
| 629 | |
| 630 | /* allow the security API to have its say */ |
| 631 | ret = security_file_mmap(file, reqprot, prot, flags); |
| 632 | if (ret < 0) |
| 633 | return ret; |
| 634 | |
| 635 | /* looks okay */ |
| 636 | *_capabilities = capabilities; |
| 637 | return 0; |
| 638 | } |
| 639 | |
| 640 | /* |
| 641 | * we've determined that we can make the mapping, now translate what we |
| 642 | * now know into VMA flags |
| 643 | */ |
| 644 | static unsigned long determine_vm_flags(struct file *file, |
| 645 | unsigned long prot, |
| 646 | unsigned long flags, |
| 647 | unsigned long capabilities) |
| 648 | { |
| 649 | unsigned long vm_flags; |
| 650 | |
| 651 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); |
| 652 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| 653 | /* vm_flags |= mm->def_flags; */ |
| 654 | |
| 655 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { |
| 656 | /* attempt to share read-only copies of mapped file chunks */ |
| 657 | if (file && !(prot & PROT_WRITE)) |
| 658 | vm_flags |= VM_MAYSHARE; |
| 659 | } |
| 660 | else { |
| 661 | /* overlay a shareable mapping on the backing device or inode |
| 662 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and |
| 663 | * romfs/cramfs */ |
| 664 | if (flags & MAP_SHARED) |
| 665 | vm_flags |= VM_MAYSHARE | VM_SHARED; |
| 666 | else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0) |
| 667 | vm_flags |= VM_MAYSHARE; |
| 668 | } |
| 669 | |
| 670 | /* refuse to let anyone share private mappings with this process if |
| 671 | * it's being traced - otherwise breakpoints set in it may interfere |
| 672 | * with another untraced process |
| 673 | */ |
| 674 | if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED)) |
| 675 | vm_flags &= ~VM_MAYSHARE; |
| 676 | |
| 677 | return vm_flags; |
| 678 | } |
| 679 | |
| 680 | /* |
| 681 | * set up a shared mapping on a file |
| 682 | */ |
| 683 | static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len) |
| 684 | { |
| 685 | int ret; |
| 686 | |
| 687 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
| 688 | if (ret != -ENOSYS) |
| 689 | return ret; |
| 690 | |
| 691 | /* getting an ENOSYS error indicates that direct mmap isn't |
| 692 | * possible (as opposed to tried but failed) so we'll fall |
| 693 | * through to making a private copy of the data and mapping |
| 694 | * that if we can */ |
| 695 | return -ENODEV; |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * set up a private mapping or an anonymous shared mapping |
| 700 | */ |
| 701 | static int do_mmap_private(struct vm_area_struct *vma, unsigned long len) |
| 702 | { |
| 703 | void *base; |
| 704 | int ret; |
| 705 | |
| 706 | /* invoke the file's mapping function so that it can keep track of |
| 707 | * shared mappings on devices or memory |
| 708 | * - VM_MAYSHARE will be set if it may attempt to share |
| 709 | */ |
| 710 | if (vma->vm_file) { |
| 711 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
| 712 | if (ret != -ENOSYS) { |
| 713 | /* shouldn't return success if we're not sharing */ |
| 714 | BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE)); |
| 715 | return ret; /* success or a real error */ |
| 716 | } |
| 717 | |
| 718 | /* getting an ENOSYS error indicates that direct mmap isn't |
| 719 | * possible (as opposed to tried but failed) so we'll try to |
| 720 | * make a private copy of the data and map that instead */ |
| 721 | } |
| 722 | |
| 723 | /* allocate some memory to hold the mapping |
| 724 | * - note that this may not return a page-aligned address if the object |
| 725 | * we're allocating is smaller than a page |
| 726 | */ |
Nick Piggin | 8409751 | 2006-03-22 00:08:34 -0800 | [diff] [blame] | 727 | base = kmalloc(len, GFP_KERNEL|__GFP_COMP); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | if (!base) |
| 729 | goto enomem; |
| 730 | |
| 731 | vma->vm_start = (unsigned long) base; |
| 732 | vma->vm_end = vma->vm_start + len; |
| 733 | vma->vm_flags |= VM_MAPPED_COPY; |
| 734 | |
| 735 | #ifdef WARN_ON_SLACK |
| 736 | if (len + WARN_ON_SLACK <= kobjsize(result)) |
| 737 | printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n", |
| 738 | len, current->pid, kobjsize(result) - len); |
| 739 | #endif |
| 740 | |
| 741 | if (vma->vm_file) { |
| 742 | /* read the contents of a file into the copy */ |
| 743 | mm_segment_t old_fs; |
| 744 | loff_t fpos; |
| 745 | |
| 746 | fpos = vma->vm_pgoff; |
| 747 | fpos <<= PAGE_SHIFT; |
| 748 | |
| 749 | old_fs = get_fs(); |
| 750 | set_fs(KERNEL_DS); |
| 751 | ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); |
| 752 | set_fs(old_fs); |
| 753 | |
| 754 | if (ret < 0) |
| 755 | goto error_free; |
| 756 | |
| 757 | /* clear the last little bit */ |
| 758 | if (ret < len) |
| 759 | memset(base + ret, 0, len - ret); |
| 760 | |
| 761 | } else { |
| 762 | /* if it's an anonymous mapping, then just clear it */ |
| 763 | memset(base, 0, len); |
| 764 | } |
| 765 | |
| 766 | return 0; |
| 767 | |
| 768 | error_free: |
| 769 | kfree(base); |
| 770 | vma->vm_start = 0; |
| 771 | return ret; |
| 772 | |
| 773 | enomem: |
| 774 | printk("Allocation of length %lu from process %d failed\n", |
| 775 | len, current->pid); |
| 776 | show_free_areas(); |
| 777 | return -ENOMEM; |
| 778 | } |
| 779 | |
| 780 | /* |
| 781 | * handle mapping creation for uClinux |
| 782 | */ |
| 783 | unsigned long do_mmap_pgoff(struct file *file, |
| 784 | unsigned long addr, |
| 785 | unsigned long len, |
| 786 | unsigned long prot, |
| 787 | unsigned long flags, |
| 788 | unsigned long pgoff) |
| 789 | { |
| 790 | struct vm_list_struct *vml = NULL; |
| 791 | struct vm_area_struct *vma = NULL; |
| 792 | struct rb_node *rb; |
| 793 | unsigned long capabilities, vm_flags; |
| 794 | void *result; |
| 795 | int ret; |
| 796 | |
| 797 | /* decide whether we should attempt the mapping, and if so what sort of |
| 798 | * mapping */ |
| 799 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
| 800 | &capabilities); |
| 801 | if (ret < 0) |
| 802 | return ret; |
| 803 | |
| 804 | /* we've determined that we can make the mapping, now translate what we |
| 805 | * now know into VMA flags */ |
| 806 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
| 807 | |
| 808 | /* we're going to need to record the mapping if it works */ |
| 809 | vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL); |
| 810 | if (!vml) |
| 811 | goto error_getting_vml; |
| 812 | memset(vml, 0, sizeof(*vml)); |
| 813 | |
| 814 | down_write(&nommu_vma_sem); |
| 815 | |
| 816 | /* if we want to share, we need to check for VMAs created by other |
| 817 | * mmap() calls that overlap with our proposed mapping |
| 818 | * - we can only share with an exact match on most regular files |
| 819 | * - shared mappings on character devices and memory backed files are |
| 820 | * permitted to overlap inexactly as far as we are concerned for in |
| 821 | * these cases, sharing is handled in the driver or filesystem rather |
| 822 | * than here |
| 823 | */ |
| 824 | if (vm_flags & VM_MAYSHARE) { |
| 825 | unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 826 | unsigned long vmpglen; |
| 827 | |
| 828 | for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) { |
| 829 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); |
| 830 | |
| 831 | if (!(vma->vm_flags & VM_MAYSHARE)) |
| 832 | continue; |
| 833 | |
| 834 | /* search for overlapping mappings on the same file */ |
| 835 | if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode) |
| 836 | continue; |
| 837 | |
| 838 | if (vma->vm_pgoff >= pgoff + pglen) |
| 839 | continue; |
| 840 | |
| 841 | vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1; |
| 842 | vmpglen >>= PAGE_SHIFT; |
| 843 | if (pgoff >= vma->vm_pgoff + vmpglen) |
| 844 | continue; |
| 845 | |
| 846 | /* handle inexactly overlapping matches between mappings */ |
| 847 | if (vma->vm_pgoff != pgoff || vmpglen != pglen) { |
| 848 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
| 849 | goto sharing_violation; |
| 850 | continue; |
| 851 | } |
| 852 | |
| 853 | /* we've found a VMA we can share */ |
| 854 | atomic_inc(&vma->vm_usage); |
| 855 | |
| 856 | vml->vma = vma; |
| 857 | result = (void *) vma->vm_start; |
| 858 | goto shared; |
| 859 | } |
| 860 | |
| 861 | vma = NULL; |
| 862 | |
| 863 | /* obtain the address at which to make a shared mapping |
| 864 | * - this is the hook for quasi-memory character devices to |
| 865 | * tell us the location of a shared mapping |
| 866 | */ |
| 867 | if (file && file->f_op->get_unmapped_area) { |
| 868 | addr = file->f_op->get_unmapped_area(file, addr, len, |
| 869 | pgoff, flags); |
| 870 | if (IS_ERR((void *) addr)) { |
| 871 | ret = addr; |
| 872 | if (ret != (unsigned long) -ENOSYS) |
| 873 | goto error; |
| 874 | |
| 875 | /* the driver refused to tell us where to site |
| 876 | * the mapping so we'll have to attempt to copy |
| 877 | * it */ |
| 878 | ret = (unsigned long) -ENODEV; |
| 879 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
| 880 | goto error; |
| 881 | |
| 882 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
| 883 | } |
| 884 | } |
| 885 | } |
| 886 | |
| 887 | /* we're going to need a VMA struct as well */ |
| 888 | vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL); |
| 889 | if (!vma) |
| 890 | goto error_getting_vma; |
| 891 | |
| 892 | memset(vma, 0, sizeof(*vma)); |
| 893 | INIT_LIST_HEAD(&vma->anon_vma_node); |
| 894 | atomic_set(&vma->vm_usage, 1); |
| 895 | if (file) |
| 896 | get_file(file); |
| 897 | vma->vm_file = file; |
| 898 | vma->vm_flags = vm_flags; |
| 899 | vma->vm_start = addr; |
| 900 | vma->vm_end = addr + len; |
| 901 | vma->vm_pgoff = pgoff; |
| 902 | |
| 903 | vml->vma = vma; |
| 904 | |
| 905 | /* set up the mapping */ |
| 906 | if (file && vma->vm_flags & VM_SHARED) |
| 907 | ret = do_mmap_shared_file(vma, len); |
| 908 | else |
| 909 | ret = do_mmap_private(vma, len); |
| 910 | if (ret < 0) |
| 911 | goto error; |
| 912 | |
| 913 | /* okay... we have a mapping; now we have to register it */ |
| 914 | result = (void *) vma->vm_start; |
| 915 | |
| 916 | if (vma->vm_flags & VM_MAPPED_COPY) { |
| 917 | realalloc += kobjsize(result); |
| 918 | askedalloc += len; |
| 919 | } |
| 920 | |
| 921 | realalloc += kobjsize(vma); |
| 922 | askedalloc += sizeof(*vma); |
| 923 | |
| 924 | current->mm->total_vm += len >> PAGE_SHIFT; |
| 925 | |
| 926 | add_nommu_vma(vma); |
| 927 | |
| 928 | shared: |
| 929 | realalloc += kobjsize(vml); |
| 930 | askedalloc += sizeof(*vml); |
| 931 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 932 | add_vma_to_mm(current->mm, vml); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | |
| 934 | up_write(&nommu_vma_sem); |
| 935 | |
| 936 | if (prot & PROT_EXEC) |
| 937 | flush_icache_range((unsigned long) result, |
| 938 | (unsigned long) result + len); |
| 939 | |
| 940 | #ifdef DEBUG |
| 941 | printk("do_mmap:\n"); |
| 942 | show_process_blocks(); |
| 943 | #endif |
| 944 | |
| 945 | return (unsigned long) result; |
| 946 | |
| 947 | error: |
| 948 | up_write(&nommu_vma_sem); |
| 949 | kfree(vml); |
| 950 | if (vma) { |
| 951 | fput(vma->vm_file); |
| 952 | kfree(vma); |
| 953 | } |
| 954 | return ret; |
| 955 | |
| 956 | sharing_violation: |
| 957 | up_write(&nommu_vma_sem); |
| 958 | printk("Attempt to share mismatched mappings\n"); |
| 959 | kfree(vml); |
| 960 | return -EINVAL; |
| 961 | |
| 962 | error_getting_vma: |
| 963 | up_write(&nommu_vma_sem); |
| 964 | kfree(vml); |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 965 | printk("Allocation of vma for %lu byte allocation from process %d failed\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | len, current->pid); |
| 967 | show_free_areas(); |
| 968 | return -ENOMEM; |
| 969 | |
| 970 | error_getting_vml: |
| 971 | printk("Allocation of vml for %lu byte allocation from process %d failed\n", |
| 972 | len, current->pid); |
| 973 | show_free_areas(); |
| 974 | return -ENOMEM; |
| 975 | } |
| 976 | |
| 977 | /* |
| 978 | * handle mapping disposal for uClinux |
| 979 | */ |
| 980 | static void put_vma(struct vm_area_struct *vma) |
| 981 | { |
| 982 | if (vma) { |
| 983 | down_write(&nommu_vma_sem); |
| 984 | |
| 985 | if (atomic_dec_and_test(&vma->vm_usage)) { |
| 986 | delete_nommu_vma(vma); |
| 987 | |
| 988 | if (vma->vm_ops && vma->vm_ops->close) |
| 989 | vma->vm_ops->close(vma); |
| 990 | |
| 991 | /* IO memory and memory shared directly out of the pagecache from |
| 992 | * ramfs/tmpfs mustn't be released here */ |
| 993 | if (vma->vm_flags & VM_MAPPED_COPY) { |
| 994 | realalloc -= kobjsize((void *) vma->vm_start); |
| 995 | askedalloc -= vma->vm_end - vma->vm_start; |
| 996 | kfree((void *) vma->vm_start); |
| 997 | } |
| 998 | |
| 999 | realalloc -= kobjsize(vma); |
| 1000 | askedalloc -= sizeof(*vma); |
| 1001 | |
| 1002 | if (vma->vm_file) |
| 1003 | fput(vma->vm_file); |
| 1004 | kfree(vma); |
| 1005 | } |
| 1006 | |
| 1007 | up_write(&nommu_vma_sem); |
| 1008 | } |
| 1009 | } |
| 1010 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 1011 | /* |
| 1012 | * release a mapping |
| 1013 | * - under NOMMU conditions the parameters must match exactly to the mapping to |
| 1014 | * be removed |
| 1015 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1016 | int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) |
| 1017 | { |
| 1018 | struct vm_list_struct *vml, **parent; |
| 1019 | unsigned long end = addr + len; |
| 1020 | |
| 1021 | #ifdef DEBUG |
| 1022 | printk("do_munmap:\n"); |
| 1023 | #endif |
| 1024 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 1025 | for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) { |
| 1026 | if ((*parent)->vma->vm_start > addr) |
| 1027 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | if ((*parent)->vma->vm_start == addr && |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 1029 | ((len == 0) || ((*parent)->vma->vm_end == end))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1030 | goto found; |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 1031 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1032 | |
| 1033 | printk("munmap of non-mmaped memory by process %d (%s): %p\n", |
| 1034 | current->pid, current->comm, (void *) addr); |
| 1035 | return -EINVAL; |
| 1036 | |
| 1037 | found: |
| 1038 | vml = *parent; |
| 1039 | |
| 1040 | put_vma(vml->vma); |
| 1041 | |
| 1042 | *parent = vml->next; |
| 1043 | realalloc -= kobjsize(vml); |
| 1044 | askedalloc -= sizeof(*vml); |
| 1045 | kfree(vml); |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 1046 | |
| 1047 | update_hiwater_vm(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1048 | mm->total_vm -= len >> PAGE_SHIFT; |
| 1049 | |
| 1050 | #ifdef DEBUG |
| 1051 | show_process_blocks(); |
| 1052 | #endif |
| 1053 | |
| 1054 | return 0; |
| 1055 | } |
| 1056 | |
David Howells | 3034097 | 2006-09-27 01:50:20 -0700 | [diff] [blame] | 1057 | asmlinkage long sys_munmap(unsigned long addr, size_t len) |
| 1058 | { |
| 1059 | int ret; |
| 1060 | struct mm_struct *mm = current->mm; |
| 1061 | |
| 1062 | down_write(&mm->mmap_sem); |
| 1063 | ret = do_munmap(mm, addr, len); |
| 1064 | up_write(&mm->mmap_sem); |
| 1065 | return ret; |
| 1066 | } |
| 1067 | |
| 1068 | /* |
| 1069 | * Release all mappings |
| 1070 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1071 | void exit_mmap(struct mm_struct * mm) |
| 1072 | { |
| 1073 | struct vm_list_struct *tmp; |
| 1074 | |
| 1075 | if (mm) { |
| 1076 | #ifdef DEBUG |
| 1077 | printk("Exit_mmap:\n"); |
| 1078 | #endif |
| 1079 | |
| 1080 | mm->total_vm = 0; |
| 1081 | |
| 1082 | while ((tmp = mm->context.vmlist)) { |
| 1083 | mm->context.vmlist = tmp->next; |
| 1084 | put_vma(tmp->vma); |
| 1085 | |
| 1086 | realalloc -= kobjsize(tmp); |
| 1087 | askedalloc -= sizeof(*tmp); |
| 1088 | kfree(tmp); |
| 1089 | } |
| 1090 | |
| 1091 | #ifdef DEBUG |
| 1092 | show_process_blocks(); |
| 1093 | #endif |
| 1094 | } |
| 1095 | } |
| 1096 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | unsigned long do_brk(unsigned long addr, unsigned long len) |
| 1098 | { |
| 1099 | return -ENOMEM; |
| 1100 | } |
| 1101 | |
| 1102 | /* |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1103 | * expand (or shrink) an existing mapping, potentially moving it at the same |
| 1104 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1105 | * |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1106 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
| 1107 | * as long as it stays within the hole allocated by the kmalloc() call in |
| 1108 | * do_mmap_pgoff() and the block is not shareable |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | * |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1110 | * MREMAP_FIXED is not supported under NOMMU conditions |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | */ |
| 1112 | unsigned long do_mremap(unsigned long addr, |
| 1113 | unsigned long old_len, unsigned long new_len, |
| 1114 | unsigned long flags, unsigned long new_addr) |
| 1115 | { |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1116 | struct vm_area_struct *vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1117 | |
| 1118 | /* insanity checks first */ |
| 1119 | if (new_len == 0) |
| 1120 | return (unsigned long) -EINVAL; |
| 1121 | |
| 1122 | if (flags & MREMAP_FIXED && new_addr != addr) |
| 1123 | return (unsigned long) -EINVAL; |
| 1124 | |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1125 | vma = find_vma_exact(current->mm, addr); |
| 1126 | if (!vma) |
| 1127 | return (unsigned long) -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1129 | if (vma->vm_end != vma->vm_start + old_len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | return (unsigned long) -EFAULT; |
| 1131 | |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1132 | if (vma->vm_flags & VM_MAYSHARE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1133 | return (unsigned long) -EPERM; |
| 1134 | |
| 1135 | if (new_len > kobjsize((void *) addr)) |
| 1136 | return (unsigned long) -ENOMEM; |
| 1137 | |
| 1138 | /* all checks complete - do it */ |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1139 | vma->vm_end = vma->vm_start + new_len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | |
| 1141 | askedalloc -= old_len; |
| 1142 | askedalloc += new_len; |
| 1143 | |
David Howells | 6fa5f80 | 2006-09-27 01:50:21 -0700 | [diff] [blame] | 1144 | return vma->vm_start; |
| 1145 | } |
| 1146 | |
| 1147 | asmlinkage unsigned long sys_mremap(unsigned long addr, |
| 1148 | unsigned long old_len, unsigned long new_len, |
| 1149 | unsigned long flags, unsigned long new_addr) |
| 1150 | { |
| 1151 | unsigned long ret; |
| 1152 | |
| 1153 | down_write(¤t->mm->mmap_sem); |
| 1154 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
| 1155 | up_write(¤t->mm->mmap_sem); |
| 1156 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1157 | } |
| 1158 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1159 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1160 | unsigned int foll_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | { |
| 1162 | return NULL; |
| 1163 | } |
| 1164 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
| 1166 | unsigned long to, unsigned long size, pgprot_t prot) |
| 1167 | { |
Greg Ungerer | 66aa2b4 | 2005-09-12 11:18:10 +1000 | [diff] [blame] | 1168 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
| 1169 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | } |
Luke Yang | 22c4af4 | 2006-07-14 00:24:09 -0700 | [diff] [blame] | 1171 | EXPORT_SYMBOL(remap_pfn_range); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1172 | |
| 1173 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
| 1174 | { |
| 1175 | } |
| 1176 | |
| 1177 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, |
| 1178 | unsigned long len, unsigned long pgoff, unsigned long flags) |
| 1179 | { |
| 1180 | return -ENOMEM; |
| 1181 | } |
| 1182 | |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 1183 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | { |
| 1185 | } |
| 1186 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1187 | void unmap_mapping_range(struct address_space *mapping, |
| 1188 | loff_t const holebegin, loff_t const holelen, |
| 1189 | int even_cows) |
| 1190 | { |
| 1191 | } |
Luke Yang | 22c4af4 | 2006-07-14 00:24:09 -0700 | [diff] [blame] | 1192 | EXPORT_SYMBOL(unmap_mapping_range); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | |
| 1194 | /* |
| 1195 | * Check that a process has enough memory to allocate a new virtual |
| 1196 | * mapping. 0 means there is enough memory for the allocation to |
| 1197 | * succeed and -ENOMEM implies there is not. |
| 1198 | * |
| 1199 | * We currently support three overcommit policies, which are set via the |
| 1200 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
| 1201 | * |
| 1202 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
| 1203 | * Additional code 2002 Jul 20 by Robert Love. |
| 1204 | * |
| 1205 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
| 1206 | * |
| 1207 | * Note this is a helper function intended to be used by LSMs which |
| 1208 | * wish to use this logic. |
| 1209 | */ |
| 1210 | int __vm_enough_memory(long pages, int cap_sys_admin) |
| 1211 | { |
| 1212 | unsigned long free, allowed; |
| 1213 | |
| 1214 | vm_acct_memory(pages); |
| 1215 | |
| 1216 | /* |
| 1217 | * Sometimes we want to use more memory than we have |
| 1218 | */ |
| 1219 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
| 1220 | return 0; |
| 1221 | |
| 1222 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
| 1223 | unsigned long n; |
| 1224 | |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 1225 | free = global_page_state(NR_FILE_PAGES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | free += nr_swap_pages; |
| 1227 | |
| 1228 | /* |
| 1229 | * Any slabs which are created with the |
| 1230 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
| 1231 | * which are reclaimable, under pressure. The dentry |
| 1232 | * cache and most inode caches should fall into this |
| 1233 | */ |
Christoph Lameter | 972d1a7 | 2006-09-25 23:31:51 -0700 | [diff] [blame] | 1234 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1235 | |
| 1236 | /* |
| 1237 | * Leave the last 3% for root |
| 1238 | */ |
| 1239 | if (!cap_sys_admin) |
| 1240 | free -= free / 32; |
| 1241 | |
| 1242 | if (free > pages) |
| 1243 | return 0; |
| 1244 | |
| 1245 | /* |
| 1246 | * nr_free_pages() is very expensive on large systems, |
| 1247 | * only call if we're about to fail. |
| 1248 | */ |
| 1249 | n = nr_free_pages(); |
Hideo AOKI | d5ddc79 | 2006-04-10 22:53:01 -0700 | [diff] [blame] | 1250 | |
| 1251 | /* |
| 1252 | * Leave reserved pages. The pages are not for anonymous pages. |
| 1253 | */ |
| 1254 | if (n <= totalreserve_pages) |
| 1255 | goto error; |
| 1256 | else |
| 1257 | n -= totalreserve_pages; |
| 1258 | |
| 1259 | /* |
| 1260 | * Leave the last 3% for root |
| 1261 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1262 | if (!cap_sys_admin) |
| 1263 | n -= n / 32; |
| 1264 | free += n; |
| 1265 | |
| 1266 | if (free > pages) |
| 1267 | return 0; |
Hideo AOKI | d5ddc79 | 2006-04-10 22:53:01 -0700 | [diff] [blame] | 1268 | |
| 1269 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1270 | } |
| 1271 | |
| 1272 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; |
| 1273 | /* |
| 1274 | * Leave the last 3% for root |
| 1275 | */ |
| 1276 | if (!cap_sys_admin) |
| 1277 | allowed -= allowed / 32; |
| 1278 | allowed += total_swap_pages; |
| 1279 | |
| 1280 | /* Don't let a single process grow too big: |
| 1281 | leave 3% of the size of this process for other processes */ |
| 1282 | allowed -= current->mm->total_vm / 32; |
| 1283 | |
Simon Derr | 2f60f8d | 2005-08-04 19:52:03 -0700 | [diff] [blame] | 1284 | /* |
| 1285 | * cast `allowed' as a signed long because vm_committed_space |
| 1286 | * sometimes has a negative value |
| 1287 | */ |
| 1288 | if (atomic_read(&vm_committed_space) < (long)allowed) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | return 0; |
Hideo AOKI | d5ddc79 | 2006-04-10 22:53:01 -0700 | [diff] [blame] | 1290 | error: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1291 | vm_unacct_memory(pages); |
| 1292 | |
| 1293 | return -ENOMEM; |
| 1294 | } |
| 1295 | |
| 1296 | int in_gate_area_no_task(unsigned long addr) |
| 1297 | { |
| 1298 | return 0; |
| 1299 | } |
David Howells | b0e1519 | 2006-01-06 00:11:42 -0800 | [diff] [blame] | 1300 | |
| 1301 | struct page *filemap_nopage(struct vm_area_struct *area, |
| 1302 | unsigned long address, int *type) |
| 1303 | { |
| 1304 | BUG(); |
| 1305 | return NULL; |
| 1306 | } |
David Howells | 0ec76a1 | 2006-09-27 01:50:15 -0700 | [diff] [blame] | 1307 | |
| 1308 | /* |
| 1309 | * Access another process' address space. |
| 1310 | * - source/target buffer must be kernel space |
| 1311 | */ |
| 1312 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) |
| 1313 | { |
David Howells | 0ec76a1 | 2006-09-27 01:50:15 -0700 | [diff] [blame] | 1314 | struct vm_area_struct *vma; |
| 1315 | struct mm_struct *mm; |
| 1316 | |
| 1317 | if (addr + len < addr) |
| 1318 | return 0; |
| 1319 | |
| 1320 | mm = get_task_mm(tsk); |
| 1321 | if (!mm) |
| 1322 | return 0; |
| 1323 | |
| 1324 | down_read(&mm->mmap_sem); |
| 1325 | |
| 1326 | /* the access must start within one of the target process's mappings */ |
David Howells | 0159b14 | 2006-09-27 01:50:16 -0700 | [diff] [blame] | 1327 | vma = find_vma(mm, addr); |
| 1328 | if (vma) { |
David Howells | 0ec76a1 | 2006-09-27 01:50:15 -0700 | [diff] [blame] | 1329 | /* don't overrun this mapping */ |
| 1330 | if (addr + len >= vma->vm_end) |
| 1331 | len = vma->vm_end - addr; |
| 1332 | |
| 1333 | /* only read or write mappings where it is permitted */ |
David Howells | d00c7b99 | 2006-09-27 01:50:19 -0700 | [diff] [blame] | 1334 | if (write && vma->vm_flags & VM_MAYWRITE) |
David Howells | 0ec76a1 | 2006-09-27 01:50:15 -0700 | [diff] [blame] | 1335 | len -= copy_to_user((void *) addr, buf, len); |
David Howells | d00c7b99 | 2006-09-27 01:50:19 -0700 | [diff] [blame] | 1336 | else if (!write && vma->vm_flags & VM_MAYREAD) |
David Howells | 0ec76a1 | 2006-09-27 01:50:15 -0700 | [diff] [blame] | 1337 | len -= copy_from_user(buf, (void *) addr, len); |
| 1338 | else |
| 1339 | len = 0; |
| 1340 | } else { |
| 1341 | len = 0; |
| 1342 | } |
| 1343 | |
| 1344 | up_read(&mm->mmap_sem); |
| 1345 | mmput(mm); |
| 1346 | return len; |
| 1347 | } |