Commit | Line | Data |
---|---|---|
1da177e4 LT |
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); | |
1da177e4 | 47 | EXPORT_SYMBOL(__vm_enough_memory); |
6a04de6d | 48 | EXPORT_SYMBOL(num_physpages); |
1da177e4 LT |
49 | |
50 | /* list of shareable VMAs */ | |
51 | struct rb_root nommu_vma_tree = RB_ROOT; | |
52 | DECLARE_RWSEM(nommu_vma_sem); | |
53 | ||
54 | struct vm_operations_struct generic_file_vm_ops = { | |
55 | }; | |
56 | ||
66aa2b4b GU |
57 | EXPORT_SYMBOL(vfree); |
58 | EXPORT_SYMBOL(vmalloc_to_page); | |
59 | EXPORT_SYMBOL(vmalloc_32); | |
7a9166e3 LY |
60 | EXPORT_SYMBOL(vmap); |
61 | EXPORT_SYMBOL(vunmap); | |
66aa2b4b | 62 | |
1da177e4 LT |
63 | /* |
64 | * Handle all mappings that got truncated by a "truncate()" | |
65 | * system call. | |
66 | * | |
67 | * NOTE! We have to be ready to update the memory sharing | |
68 | * between the file and the memory map for a potential last | |
69 | * incomplete page. Ugly, but necessary. | |
70 | */ | |
71 | int vmtruncate(struct inode *inode, loff_t offset) | |
72 | { | |
73 | struct address_space *mapping = inode->i_mapping; | |
74 | unsigned long limit; | |
75 | ||
76 | if (inode->i_size < offset) | |
77 | goto do_expand; | |
78 | i_size_write(inode, offset); | |
79 | ||
80 | truncate_inode_pages(mapping, offset); | |
81 | goto out_truncate; | |
82 | ||
83 | do_expand: | |
84 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
85 | if (limit != RLIM_INFINITY && offset > limit) | |
86 | goto out_sig; | |
87 | if (offset > inode->i_sb->s_maxbytes) | |
88 | goto out; | |
89 | i_size_write(inode, offset); | |
90 | ||
91 | out_truncate: | |
92 | if (inode->i_op && inode->i_op->truncate) | |
93 | inode->i_op->truncate(inode); | |
94 | return 0; | |
95 | out_sig: | |
96 | send_sig(SIGXFSZ, current, 0); | |
97 | out: | |
98 | return -EFBIG; | |
99 | } | |
100 | ||
101 | EXPORT_SYMBOL(vmtruncate); | |
102 | ||
103 | /* | |
104 | * Return the total memory allocated for this pointer, not | |
105 | * just what the caller asked for. | |
106 | * | |
107 | * Doesn't have to be accurate, i.e. may have races. | |
108 | */ | |
109 | unsigned int kobjsize(const void *objp) | |
110 | { | |
111 | struct page *page; | |
112 | ||
113 | if (!objp || !((page = virt_to_page(objp)))) | |
114 | return 0; | |
115 | ||
116 | if (PageSlab(page)) | |
117 | return ksize(objp); | |
118 | ||
119 | BUG_ON(page->index < 0); | |
120 | BUG_ON(page->index >= MAX_ORDER); | |
121 | ||
122 | return (PAGE_SIZE << page->index); | |
123 | } | |
124 | ||
125 | /* | |
7b4d5b8b DH |
126 | * get a list of pages in an address range belonging to the specified process |
127 | * and indicate the VMA that covers each page | |
128 | * - this is potentially dodgy as we may end incrementing the page count of a | |
129 | * slab page or a secondary page from a compound page | |
130 | * - don't permit access to VMAs that don't support it, such as I/O mappings | |
1da177e4 LT |
131 | */ |
132 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
133 | unsigned long start, int len, int write, int force, | |
134 | struct page **pages, struct vm_area_struct **vmas) | |
135 | { | |
910e46da | 136 | struct vm_area_struct *vma; |
7b4d5b8b DH |
137 | unsigned long vm_flags; |
138 | int i; | |
139 | ||
140 | /* calculate required read or write permissions. | |
141 | * - if 'force' is set, we only require the "MAY" flags. | |
142 | */ | |
143 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); | |
144 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
145 | |
146 | for (i = 0; i < len; i++) { | |
910e46da | 147 | vma = find_vma(mm, start); |
7b4d5b8b DH |
148 | if (!vma) |
149 | goto finish_or_fault; | |
150 | ||
151 | /* protect what we can, including chardevs */ | |
152 | if (vma->vm_flags & (VM_IO | VM_PFNMAP) || | |
153 | !(vm_flags & vma->vm_flags)) | |
154 | goto finish_or_fault; | |
910e46da | 155 | |
1da177e4 LT |
156 | if (pages) { |
157 | pages[i] = virt_to_page(start); | |
158 | if (pages[i]) | |
159 | page_cache_get(pages[i]); | |
160 | } | |
161 | if (vmas) | |
910e46da | 162 | vmas[i] = vma; |
1da177e4 LT |
163 | start += PAGE_SIZE; |
164 | } | |
7b4d5b8b DH |
165 | |
166 | return i; | |
167 | ||
168 | finish_or_fault: | |
169 | return i ? : -EFAULT; | |
1da177e4 LT |
170 | } |
171 | ||
66aa2b4b GU |
172 | EXPORT_SYMBOL(get_user_pages); |
173 | ||
1da177e4 LT |
174 | DEFINE_RWLOCK(vmlist_lock); |
175 | struct vm_struct *vmlist; | |
176 | ||
177 | void vfree(void *addr) | |
178 | { | |
179 | kfree(addr); | |
180 | } | |
181 | ||
dd0fc66f | 182 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
1da177e4 LT |
183 | { |
184 | /* | |
185 | * kmalloc doesn't like __GFP_HIGHMEM for some reason | |
186 | */ | |
84097518 | 187 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
1da177e4 LT |
188 | } |
189 | ||
190 | struct page * vmalloc_to_page(void *addr) | |
191 | { | |
192 | return virt_to_page(addr); | |
193 | } | |
194 | ||
195 | unsigned long vmalloc_to_pfn(void *addr) | |
196 | { | |
197 | return page_to_pfn(virt_to_page(addr)); | |
198 | } | |
199 | ||
200 | ||
201 | long vread(char *buf, char *addr, unsigned long count) | |
202 | { | |
203 | memcpy(buf, addr, count); | |
204 | return count; | |
205 | } | |
206 | ||
207 | long vwrite(char *buf, char *addr, unsigned long count) | |
208 | { | |
209 | /* Don't allow overflow */ | |
210 | if ((unsigned long) addr + count < count) | |
211 | count = -(unsigned long) addr; | |
212 | ||
213 | memcpy(addr, buf, count); | |
214 | return(count); | |
215 | } | |
216 | ||
217 | /* | |
218 | * vmalloc - allocate virtually continguos memory | |
219 | * | |
220 | * @size: allocation size | |
221 | * | |
222 | * Allocate enough pages to cover @size from the page level | |
223 | * allocator and map them into continguos kernel virtual space. | |
224 | * | |
c1c8897f | 225 | * For tight control over page level allocator and protection flags |
1da177e4 LT |
226 | * use __vmalloc() instead. |
227 | */ | |
228 | void *vmalloc(unsigned long size) | |
229 | { | |
230 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); | |
231 | } | |
f6138882 AM |
232 | EXPORT_SYMBOL(vmalloc); |
233 | ||
234 | void *vmalloc_node(unsigned long size, int node) | |
235 | { | |
236 | return vmalloc(size); | |
237 | } | |
238 | EXPORT_SYMBOL(vmalloc_node); | |
1da177e4 LT |
239 | |
240 | /* | |
241 | * vmalloc_32 - allocate virtually continguos memory (32bit addressable) | |
242 | * | |
243 | * @size: allocation size | |
244 | * | |
245 | * Allocate enough 32bit PA addressable pages to cover @size from the | |
246 | * page level allocator and map them into continguos kernel virtual space. | |
247 | */ | |
248 | void *vmalloc_32(unsigned long size) | |
249 | { | |
250 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); | |
251 | } | |
252 | ||
253 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) | |
254 | { | |
255 | BUG(); | |
256 | return NULL; | |
257 | } | |
258 | ||
259 | void vunmap(void *addr) | |
260 | { | |
261 | BUG(); | |
262 | } | |
263 | ||
264 | /* | |
265 | * sys_brk() for the most part doesn't need the global kernel | |
266 | * lock, except when an application is doing something nasty | |
267 | * like trying to un-brk an area that has already been mapped | |
268 | * to a regular file. in this case, the unmapping will need | |
269 | * to invoke file system routines that need the global lock. | |
270 | */ | |
271 | asmlinkage unsigned long sys_brk(unsigned long brk) | |
272 | { | |
273 | struct mm_struct *mm = current->mm; | |
274 | ||
275 | if (brk < mm->start_brk || brk > mm->context.end_brk) | |
276 | return mm->brk; | |
277 | ||
278 | if (mm->brk == brk) | |
279 | return mm->brk; | |
280 | ||
281 | /* | |
282 | * Always allow shrinking brk | |
283 | */ | |
284 | if (brk <= mm->brk) { | |
285 | mm->brk = brk; | |
286 | return brk; | |
287 | } | |
288 | ||
289 | /* | |
290 | * Ok, looks good - let it rip. | |
291 | */ | |
292 | return mm->brk = brk; | |
293 | } | |
294 | ||
295 | #ifdef DEBUG | |
296 | static void show_process_blocks(void) | |
297 | { | |
298 | struct vm_list_struct *vml; | |
299 | ||
300 | printk("Process blocks %d:", current->pid); | |
301 | ||
302 | for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) { | |
303 | printk(" %p: %p", vml, vml->vma); | |
304 | if (vml->vma) | |
305 | printk(" (%d @%lx #%d)", | |
306 | kobjsize((void *) vml->vma->vm_start), | |
307 | vml->vma->vm_start, | |
308 | atomic_read(&vml->vma->vm_usage)); | |
309 | printk(vml->next ? " ->" : ".\n"); | |
310 | } | |
311 | } | |
312 | #endif /* DEBUG */ | |
313 | ||
3034097a DH |
314 | /* |
315 | * add a VMA into a process's mm_struct in the appropriate place in the list | |
316 | * - should be called with mm->mmap_sem held writelocked | |
317 | */ | |
318 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml) | |
319 | { | |
320 | struct vm_list_struct **ppv; | |
321 | ||
322 | for (ppv = ¤t->mm->context.vmlist; *ppv; ppv = &(*ppv)->next) | |
323 | if ((*ppv)->vma->vm_start > vml->vma->vm_start) | |
324 | break; | |
325 | ||
326 | vml->next = *ppv; | |
327 | *ppv = vml; | |
328 | } | |
329 | ||
330 | /* | |
331 | * look up the first VMA in which addr resides, NULL if none | |
332 | * - should be called with mm->mmap_sem at least held readlocked | |
333 | */ | |
334 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) | |
335 | { | |
336 | struct vm_list_struct *loop, *vml; | |
337 | ||
338 | /* search the vm_start ordered list */ | |
339 | vml = NULL; | |
340 | for (loop = mm->context.vmlist; loop; loop = loop->next) { | |
341 | if (loop->vma->vm_start > addr) | |
342 | break; | |
343 | vml = loop; | |
344 | } | |
345 | ||
346 | if (vml && vml->vma->vm_end > addr) | |
347 | return vml->vma; | |
348 | ||
349 | return NULL; | |
350 | } | |
351 | EXPORT_SYMBOL(find_vma); | |
352 | ||
930e652a DH |
353 | /* |
354 | * find a VMA | |
355 | * - we don't extend stack VMAs under NOMMU conditions | |
356 | */ | |
357 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
358 | { | |
359 | return find_vma(mm, addr); | |
360 | } | |
361 | ||
6fa5f80b DH |
362 | /* |
363 | * look up the first VMA exactly that exactly matches addr | |
364 | * - should be called with mm->mmap_sem at least held readlocked | |
365 | */ | |
366 | static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm, | |
367 | unsigned long addr) | |
368 | { | |
369 | struct vm_list_struct *vml; | |
370 | ||
371 | /* search the vm_start ordered list */ | |
372 | for (vml = mm->context.vmlist; vml; vml = vml->next) { | |
373 | if (vml->vma->vm_start == addr) | |
374 | return vml->vma; | |
375 | if (vml->vma->vm_start > addr) | |
376 | break; | |
377 | } | |
378 | ||
379 | return NULL; | |
380 | } | |
381 | ||
3034097a DH |
382 | /* |
383 | * find a VMA in the global tree | |
384 | */ | |
1da177e4 LT |
385 | static inline struct vm_area_struct *find_nommu_vma(unsigned long start) |
386 | { | |
387 | struct vm_area_struct *vma; | |
388 | struct rb_node *n = nommu_vma_tree.rb_node; | |
389 | ||
390 | while (n) { | |
391 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
392 | ||
393 | if (start < vma->vm_start) | |
394 | n = n->rb_left; | |
395 | else if (start > vma->vm_start) | |
396 | n = n->rb_right; | |
397 | else | |
398 | return vma; | |
399 | } | |
400 | ||
401 | return NULL; | |
402 | } | |
403 | ||
3034097a DH |
404 | /* |
405 | * add a VMA in the global tree | |
406 | */ | |
1da177e4 LT |
407 | static void add_nommu_vma(struct vm_area_struct *vma) |
408 | { | |
409 | struct vm_area_struct *pvma; | |
410 | struct address_space *mapping; | |
411 | struct rb_node **p = &nommu_vma_tree.rb_node; | |
412 | struct rb_node *parent = NULL; | |
413 | ||
414 | /* add the VMA to the mapping */ | |
415 | if (vma->vm_file) { | |
416 | mapping = vma->vm_file->f_mapping; | |
417 | ||
418 | flush_dcache_mmap_lock(mapping); | |
419 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
420 | flush_dcache_mmap_unlock(mapping); | |
421 | } | |
422 | ||
423 | /* add the VMA to the master list */ | |
424 | while (*p) { | |
425 | parent = *p; | |
426 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); | |
427 | ||
428 | if (vma->vm_start < pvma->vm_start) { | |
429 | p = &(*p)->rb_left; | |
430 | } | |
431 | else if (vma->vm_start > pvma->vm_start) { | |
432 | p = &(*p)->rb_right; | |
433 | } | |
434 | else { | |
435 | /* mappings are at the same address - this can only | |
436 | * happen for shared-mem chardevs and shared file | |
437 | * mappings backed by ramfs/tmpfs */ | |
438 | BUG_ON(!(pvma->vm_flags & VM_SHARED)); | |
439 | ||
440 | if (vma < pvma) | |
441 | p = &(*p)->rb_left; | |
442 | else if (vma > pvma) | |
443 | p = &(*p)->rb_right; | |
444 | else | |
445 | BUG(); | |
446 | } | |
447 | } | |
448 | ||
449 | rb_link_node(&vma->vm_rb, parent, p); | |
450 | rb_insert_color(&vma->vm_rb, &nommu_vma_tree); | |
451 | } | |
452 | ||
3034097a DH |
453 | /* |
454 | * delete a VMA from the global list | |
455 | */ | |
1da177e4 LT |
456 | static void delete_nommu_vma(struct vm_area_struct *vma) |
457 | { | |
458 | struct address_space *mapping; | |
459 | ||
460 | /* remove the VMA from the mapping */ | |
461 | if (vma->vm_file) { | |
462 | mapping = vma->vm_file->f_mapping; | |
463 | ||
464 | flush_dcache_mmap_lock(mapping); | |
465 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
466 | flush_dcache_mmap_unlock(mapping); | |
467 | } | |
468 | ||
469 | /* remove from the master list */ | |
470 | rb_erase(&vma->vm_rb, &nommu_vma_tree); | |
471 | } | |
472 | ||
473 | /* | |
474 | * determine whether a mapping should be permitted and, if so, what sort of | |
475 | * mapping we're capable of supporting | |
476 | */ | |
477 | static int validate_mmap_request(struct file *file, | |
478 | unsigned long addr, | |
479 | unsigned long len, | |
480 | unsigned long prot, | |
481 | unsigned long flags, | |
482 | unsigned long pgoff, | |
483 | unsigned long *_capabilities) | |
484 | { | |
485 | unsigned long capabilities; | |
486 | unsigned long reqprot = prot; | |
487 | int ret; | |
488 | ||
489 | /* do the simple checks first */ | |
490 | if (flags & MAP_FIXED || addr) { | |
491 | printk(KERN_DEBUG | |
492 | "%d: Can't do fixed-address/overlay mmap of RAM\n", | |
493 | current->pid); | |
494 | return -EINVAL; | |
495 | } | |
496 | ||
497 | if ((flags & MAP_TYPE) != MAP_PRIVATE && | |
498 | (flags & MAP_TYPE) != MAP_SHARED) | |
499 | return -EINVAL; | |
500 | ||
f81cff0d | 501 | if (!len) |
1da177e4 LT |
502 | return -EINVAL; |
503 | ||
f81cff0d MF |
504 | /* Careful about overflows.. */ |
505 | len = PAGE_ALIGN(len); | |
506 | if (!len || len > TASK_SIZE) | |
507 | return -ENOMEM; | |
508 | ||
1da177e4 LT |
509 | /* offset overflow? */ |
510 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
f81cff0d | 511 | return -EOVERFLOW; |
1da177e4 LT |
512 | |
513 | if (file) { | |
514 | /* validate file mapping requests */ | |
515 | struct address_space *mapping; | |
516 | ||
517 | /* files must support mmap */ | |
518 | if (!file->f_op || !file->f_op->mmap) | |
519 | return -ENODEV; | |
520 | ||
521 | /* work out if what we've got could possibly be shared | |
522 | * - we support chardevs that provide their own "memory" | |
523 | * - we support files/blockdevs that are memory backed | |
524 | */ | |
525 | mapping = file->f_mapping; | |
526 | if (!mapping) | |
e9536ae7 | 527 | mapping = file->f_path.dentry->d_inode->i_mapping; |
1da177e4 LT |
528 | |
529 | capabilities = 0; | |
530 | if (mapping && mapping->backing_dev_info) | |
531 | capabilities = mapping->backing_dev_info->capabilities; | |
532 | ||
533 | if (!capabilities) { | |
534 | /* no explicit capabilities set, so assume some | |
535 | * defaults */ | |
e9536ae7 | 536 | switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
1da177e4 LT |
537 | case S_IFREG: |
538 | case S_IFBLK: | |
539 | capabilities = BDI_CAP_MAP_COPY; | |
540 | break; | |
541 | ||
542 | case S_IFCHR: | |
543 | capabilities = | |
544 | BDI_CAP_MAP_DIRECT | | |
545 | BDI_CAP_READ_MAP | | |
546 | BDI_CAP_WRITE_MAP; | |
547 | break; | |
548 | ||
549 | default: | |
550 | return -EINVAL; | |
551 | } | |
552 | } | |
553 | ||
554 | /* eliminate any capabilities that we can't support on this | |
555 | * device */ | |
556 | if (!file->f_op->get_unmapped_area) | |
557 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
558 | if (!file->f_op->read) | |
559 | capabilities &= ~BDI_CAP_MAP_COPY; | |
560 | ||
561 | if (flags & MAP_SHARED) { | |
562 | /* do checks for writing, appending and locking */ | |
563 | if ((prot & PROT_WRITE) && | |
564 | !(file->f_mode & FMODE_WRITE)) | |
565 | return -EACCES; | |
566 | ||
e9536ae7 | 567 | if (IS_APPEND(file->f_path.dentry->d_inode) && |
1da177e4 LT |
568 | (file->f_mode & FMODE_WRITE)) |
569 | return -EACCES; | |
570 | ||
e9536ae7 | 571 | if (locks_verify_locked(file->f_path.dentry->d_inode)) |
1da177e4 LT |
572 | return -EAGAIN; |
573 | ||
574 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
575 | return -ENODEV; | |
576 | ||
577 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || | |
578 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || | |
579 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) | |
580 | ) { | |
581 | printk("MAP_SHARED not completely supported on !MMU\n"); | |
582 | return -EINVAL; | |
583 | } | |
584 | ||
585 | /* we mustn't privatise shared mappings */ | |
586 | capabilities &= ~BDI_CAP_MAP_COPY; | |
587 | } | |
588 | else { | |
589 | /* we're going to read the file into private memory we | |
590 | * allocate */ | |
591 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
592 | return -ENODEV; | |
593 | ||
594 | /* we don't permit a private writable mapping to be | |
595 | * shared with the backing device */ | |
596 | if (prot & PROT_WRITE) | |
597 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
598 | } | |
599 | ||
600 | /* handle executable mappings and implied executable | |
601 | * mappings */ | |
e9536ae7 | 602 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1da177e4 LT |
603 | if (prot & PROT_EXEC) |
604 | return -EPERM; | |
605 | } | |
606 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { | |
607 | /* handle implication of PROT_EXEC by PROT_READ */ | |
608 | if (current->personality & READ_IMPLIES_EXEC) { | |
609 | if (capabilities & BDI_CAP_EXEC_MAP) | |
610 | prot |= PROT_EXEC; | |
611 | } | |
612 | } | |
613 | else if ((prot & PROT_READ) && | |
614 | (prot & PROT_EXEC) && | |
615 | !(capabilities & BDI_CAP_EXEC_MAP) | |
616 | ) { | |
617 | /* backing file is not executable, try to copy */ | |
618 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
619 | } | |
620 | } | |
621 | else { | |
622 | /* anonymous mappings are always memory backed and can be | |
623 | * privately mapped | |
624 | */ | |
625 | capabilities = BDI_CAP_MAP_COPY; | |
626 | ||
627 | /* handle PROT_EXEC implication by PROT_READ */ | |
628 | if ((prot & PROT_READ) && | |
629 | (current->personality & READ_IMPLIES_EXEC)) | |
630 | prot |= PROT_EXEC; | |
631 | } | |
632 | ||
633 | /* allow the security API to have its say */ | |
634 | ret = security_file_mmap(file, reqprot, prot, flags); | |
635 | if (ret < 0) | |
636 | return ret; | |
637 | ||
638 | /* looks okay */ | |
639 | *_capabilities = capabilities; | |
640 | return 0; | |
641 | } | |
642 | ||
643 | /* | |
644 | * we've determined that we can make the mapping, now translate what we | |
645 | * now know into VMA flags | |
646 | */ | |
647 | static unsigned long determine_vm_flags(struct file *file, | |
648 | unsigned long prot, | |
649 | unsigned long flags, | |
650 | unsigned long capabilities) | |
651 | { | |
652 | unsigned long vm_flags; | |
653 | ||
654 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); | |
655 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
656 | /* vm_flags |= mm->def_flags; */ | |
657 | ||
658 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { | |
659 | /* attempt to share read-only copies of mapped file chunks */ | |
660 | if (file && !(prot & PROT_WRITE)) | |
661 | vm_flags |= VM_MAYSHARE; | |
662 | } | |
663 | else { | |
664 | /* overlay a shareable mapping on the backing device or inode | |
665 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and | |
666 | * romfs/cramfs */ | |
667 | if (flags & MAP_SHARED) | |
668 | vm_flags |= VM_MAYSHARE | VM_SHARED; | |
669 | else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0) | |
670 | vm_flags |= VM_MAYSHARE; | |
671 | } | |
672 | ||
673 | /* refuse to let anyone share private mappings with this process if | |
674 | * it's being traced - otherwise breakpoints set in it may interfere | |
675 | * with another untraced process | |
676 | */ | |
677 | if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED)) | |
678 | vm_flags &= ~VM_MAYSHARE; | |
679 | ||
680 | return vm_flags; | |
681 | } | |
682 | ||
683 | /* | |
684 | * set up a shared mapping on a file | |
685 | */ | |
686 | static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len) | |
687 | { | |
688 | int ret; | |
689 | ||
690 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
691 | if (ret != -ENOSYS) | |
692 | return ret; | |
693 | ||
694 | /* getting an ENOSYS error indicates that direct mmap isn't | |
695 | * possible (as opposed to tried but failed) so we'll fall | |
696 | * through to making a private copy of the data and mapping | |
697 | * that if we can */ | |
698 | return -ENODEV; | |
699 | } | |
700 | ||
701 | /* | |
702 | * set up a private mapping or an anonymous shared mapping | |
703 | */ | |
704 | static int do_mmap_private(struct vm_area_struct *vma, unsigned long len) | |
705 | { | |
706 | void *base; | |
707 | int ret; | |
708 | ||
709 | /* invoke the file's mapping function so that it can keep track of | |
710 | * shared mappings on devices or memory | |
711 | * - VM_MAYSHARE will be set if it may attempt to share | |
712 | */ | |
713 | if (vma->vm_file) { | |
714 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
715 | if (ret != -ENOSYS) { | |
716 | /* shouldn't return success if we're not sharing */ | |
717 | BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE)); | |
718 | return ret; /* success or a real error */ | |
719 | } | |
720 | ||
721 | /* getting an ENOSYS error indicates that direct mmap isn't | |
722 | * possible (as opposed to tried but failed) so we'll try to | |
723 | * make a private copy of the data and map that instead */ | |
724 | } | |
725 | ||
726 | /* allocate some memory to hold the mapping | |
727 | * - note that this may not return a page-aligned address if the object | |
728 | * we're allocating is smaller than a page | |
729 | */ | |
84097518 | 730 | base = kmalloc(len, GFP_KERNEL|__GFP_COMP); |
1da177e4 LT |
731 | if (!base) |
732 | goto enomem; | |
733 | ||
734 | vma->vm_start = (unsigned long) base; | |
735 | vma->vm_end = vma->vm_start + len; | |
736 | vma->vm_flags |= VM_MAPPED_COPY; | |
737 | ||
738 | #ifdef WARN_ON_SLACK | |
739 | if (len + WARN_ON_SLACK <= kobjsize(result)) | |
740 | printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n", | |
741 | len, current->pid, kobjsize(result) - len); | |
742 | #endif | |
743 | ||
744 | if (vma->vm_file) { | |
745 | /* read the contents of a file into the copy */ | |
746 | mm_segment_t old_fs; | |
747 | loff_t fpos; | |
748 | ||
749 | fpos = vma->vm_pgoff; | |
750 | fpos <<= PAGE_SHIFT; | |
751 | ||
752 | old_fs = get_fs(); | |
753 | set_fs(KERNEL_DS); | |
754 | ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); | |
755 | set_fs(old_fs); | |
756 | ||
757 | if (ret < 0) | |
758 | goto error_free; | |
759 | ||
760 | /* clear the last little bit */ | |
761 | if (ret < len) | |
762 | memset(base + ret, 0, len - ret); | |
763 | ||
764 | } else { | |
765 | /* if it's an anonymous mapping, then just clear it */ | |
766 | memset(base, 0, len); | |
767 | } | |
768 | ||
769 | return 0; | |
770 | ||
771 | error_free: | |
772 | kfree(base); | |
773 | vma->vm_start = 0; | |
774 | return ret; | |
775 | ||
776 | enomem: | |
777 | printk("Allocation of length %lu from process %d failed\n", | |
778 | len, current->pid); | |
779 | show_free_areas(); | |
780 | return -ENOMEM; | |
781 | } | |
782 | ||
783 | /* | |
784 | * handle mapping creation for uClinux | |
785 | */ | |
786 | unsigned long do_mmap_pgoff(struct file *file, | |
787 | unsigned long addr, | |
788 | unsigned long len, | |
789 | unsigned long prot, | |
790 | unsigned long flags, | |
791 | unsigned long pgoff) | |
792 | { | |
793 | struct vm_list_struct *vml = NULL; | |
794 | struct vm_area_struct *vma = NULL; | |
795 | struct rb_node *rb; | |
796 | unsigned long capabilities, vm_flags; | |
797 | void *result; | |
798 | int ret; | |
799 | ||
800 | /* decide whether we should attempt the mapping, and if so what sort of | |
801 | * mapping */ | |
802 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, | |
803 | &capabilities); | |
804 | if (ret < 0) | |
805 | return ret; | |
806 | ||
807 | /* we've determined that we can make the mapping, now translate what we | |
808 | * now know into VMA flags */ | |
809 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); | |
810 | ||
811 | /* we're going to need to record the mapping if it works */ | |
4668edc3 | 812 | vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL); |
1da177e4 LT |
813 | if (!vml) |
814 | goto error_getting_vml; | |
1da177e4 LT |
815 | |
816 | down_write(&nommu_vma_sem); | |
817 | ||
818 | /* if we want to share, we need to check for VMAs created by other | |
819 | * mmap() calls that overlap with our proposed mapping | |
820 | * - we can only share with an exact match on most regular files | |
821 | * - shared mappings on character devices and memory backed files are | |
822 | * permitted to overlap inexactly as far as we are concerned for in | |
823 | * these cases, sharing is handled in the driver or filesystem rather | |
824 | * than here | |
825 | */ | |
826 | if (vm_flags & VM_MAYSHARE) { | |
827 | unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
828 | unsigned long vmpglen; | |
829 | ||
165b2392 DH |
830 | /* suppress VMA sharing for shared regions */ |
831 | if (vm_flags & VM_SHARED && | |
832 | capabilities & BDI_CAP_MAP_DIRECT) | |
833 | goto dont_share_VMAs; | |
834 | ||
1da177e4 LT |
835 | for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) { |
836 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); | |
837 | ||
838 | if (!(vma->vm_flags & VM_MAYSHARE)) | |
839 | continue; | |
840 | ||
841 | /* search for overlapping mappings on the same file */ | |
e9536ae7 | 842 | if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode) |
1da177e4 LT |
843 | continue; |
844 | ||
845 | if (vma->vm_pgoff >= pgoff + pglen) | |
846 | continue; | |
847 | ||
848 | vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1; | |
849 | vmpglen >>= PAGE_SHIFT; | |
850 | if (pgoff >= vma->vm_pgoff + vmpglen) | |
851 | continue; | |
852 | ||
853 | /* handle inexactly overlapping matches between mappings */ | |
854 | if (vma->vm_pgoff != pgoff || vmpglen != pglen) { | |
855 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
856 | goto sharing_violation; | |
857 | continue; | |
858 | } | |
859 | ||
860 | /* we've found a VMA we can share */ | |
861 | atomic_inc(&vma->vm_usage); | |
862 | ||
863 | vml->vma = vma; | |
864 | result = (void *) vma->vm_start; | |
865 | goto shared; | |
866 | } | |
867 | ||
165b2392 | 868 | dont_share_VMAs: |
1da177e4 LT |
869 | vma = NULL; |
870 | ||
871 | /* obtain the address at which to make a shared mapping | |
872 | * - this is the hook for quasi-memory character devices to | |
873 | * tell us the location of a shared mapping | |
874 | */ | |
875 | if (file && file->f_op->get_unmapped_area) { | |
876 | addr = file->f_op->get_unmapped_area(file, addr, len, | |
877 | pgoff, flags); | |
878 | if (IS_ERR((void *) addr)) { | |
879 | ret = addr; | |
880 | if (ret != (unsigned long) -ENOSYS) | |
881 | goto error; | |
882 | ||
883 | /* the driver refused to tell us where to site | |
884 | * the mapping so we'll have to attempt to copy | |
885 | * it */ | |
886 | ret = (unsigned long) -ENODEV; | |
887 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
888 | goto error; | |
889 | ||
890 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
891 | } | |
892 | } | |
893 | } | |
894 | ||
895 | /* we're going to need a VMA struct as well */ | |
4668edc3 | 896 | vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL); |
1da177e4 LT |
897 | if (!vma) |
898 | goto error_getting_vma; | |
899 | ||
1da177e4 LT |
900 | INIT_LIST_HEAD(&vma->anon_vma_node); |
901 | atomic_set(&vma->vm_usage, 1); | |
902 | if (file) | |
903 | get_file(file); | |
904 | vma->vm_file = file; | |
905 | vma->vm_flags = vm_flags; | |
906 | vma->vm_start = addr; | |
907 | vma->vm_end = addr + len; | |
908 | vma->vm_pgoff = pgoff; | |
909 | ||
910 | vml->vma = vma; | |
911 | ||
912 | /* set up the mapping */ | |
913 | if (file && vma->vm_flags & VM_SHARED) | |
914 | ret = do_mmap_shared_file(vma, len); | |
915 | else | |
916 | ret = do_mmap_private(vma, len); | |
917 | if (ret < 0) | |
918 | goto error; | |
919 | ||
920 | /* okay... we have a mapping; now we have to register it */ | |
921 | result = (void *) vma->vm_start; | |
922 | ||
923 | if (vma->vm_flags & VM_MAPPED_COPY) { | |
924 | realalloc += kobjsize(result); | |
925 | askedalloc += len; | |
926 | } | |
927 | ||
928 | realalloc += kobjsize(vma); | |
929 | askedalloc += sizeof(*vma); | |
930 | ||
931 | current->mm->total_vm += len >> PAGE_SHIFT; | |
932 | ||
933 | add_nommu_vma(vma); | |
934 | ||
935 | shared: | |
936 | realalloc += kobjsize(vml); | |
937 | askedalloc += sizeof(*vml); | |
938 | ||
3034097a | 939 | add_vma_to_mm(current->mm, vml); |
1da177e4 LT |
940 | |
941 | up_write(&nommu_vma_sem); | |
942 | ||
943 | if (prot & PROT_EXEC) | |
944 | flush_icache_range((unsigned long) result, | |
945 | (unsigned long) result + len); | |
946 | ||
947 | #ifdef DEBUG | |
948 | printk("do_mmap:\n"); | |
949 | show_process_blocks(); | |
950 | #endif | |
951 | ||
952 | return (unsigned long) result; | |
953 | ||
954 | error: | |
955 | up_write(&nommu_vma_sem); | |
956 | kfree(vml); | |
957 | if (vma) { | |
3fcd03e0 GL |
958 | if (vma->vm_file) |
959 | fput(vma->vm_file); | |
1da177e4 LT |
960 | kfree(vma); |
961 | } | |
962 | return ret; | |
963 | ||
964 | sharing_violation: | |
965 | up_write(&nommu_vma_sem); | |
966 | printk("Attempt to share mismatched mappings\n"); | |
967 | kfree(vml); | |
968 | return -EINVAL; | |
969 | ||
970 | error_getting_vma: | |
971 | up_write(&nommu_vma_sem); | |
972 | kfree(vml); | |
66aa2b4b | 973 | printk("Allocation of vma for %lu byte allocation from process %d failed\n", |
1da177e4 LT |
974 | len, current->pid); |
975 | show_free_areas(); | |
976 | return -ENOMEM; | |
977 | ||
978 | error_getting_vml: | |
979 | printk("Allocation of vml for %lu byte allocation from process %d failed\n", | |
980 | len, current->pid); | |
981 | show_free_areas(); | |
982 | return -ENOMEM; | |
983 | } | |
984 | ||
985 | /* | |
986 | * handle mapping disposal for uClinux | |
987 | */ | |
988 | static void put_vma(struct vm_area_struct *vma) | |
989 | { | |
990 | if (vma) { | |
991 | down_write(&nommu_vma_sem); | |
992 | ||
993 | if (atomic_dec_and_test(&vma->vm_usage)) { | |
994 | delete_nommu_vma(vma); | |
995 | ||
996 | if (vma->vm_ops && vma->vm_ops->close) | |
997 | vma->vm_ops->close(vma); | |
998 | ||
999 | /* IO memory and memory shared directly out of the pagecache from | |
1000 | * ramfs/tmpfs mustn't be released here */ | |
1001 | if (vma->vm_flags & VM_MAPPED_COPY) { | |
1002 | realalloc -= kobjsize((void *) vma->vm_start); | |
1003 | askedalloc -= vma->vm_end - vma->vm_start; | |
1004 | kfree((void *) vma->vm_start); | |
1005 | } | |
1006 | ||
1007 | realalloc -= kobjsize(vma); | |
1008 | askedalloc -= sizeof(*vma); | |
1009 | ||
1010 | if (vma->vm_file) | |
1011 | fput(vma->vm_file); | |
1012 | kfree(vma); | |
1013 | } | |
1014 | ||
1015 | up_write(&nommu_vma_sem); | |
1016 | } | |
1017 | } | |
1018 | ||
3034097a DH |
1019 | /* |
1020 | * release a mapping | |
1021 | * - under NOMMU conditions the parameters must match exactly to the mapping to | |
1022 | * be removed | |
1023 | */ | |
1da177e4 LT |
1024 | int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) |
1025 | { | |
1026 | struct vm_list_struct *vml, **parent; | |
1027 | unsigned long end = addr + len; | |
1028 | ||
1029 | #ifdef DEBUG | |
1030 | printk("do_munmap:\n"); | |
1031 | #endif | |
1032 | ||
3034097a DH |
1033 | for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) { |
1034 | if ((*parent)->vma->vm_start > addr) | |
1035 | break; | |
1da177e4 | 1036 | if ((*parent)->vma->vm_start == addr && |
66aa2b4b | 1037 | ((len == 0) || ((*parent)->vma->vm_end == end))) |
1da177e4 | 1038 | goto found; |
3034097a | 1039 | } |
1da177e4 LT |
1040 | |
1041 | printk("munmap of non-mmaped memory by process %d (%s): %p\n", | |
1042 | current->pid, current->comm, (void *) addr); | |
1043 | return -EINVAL; | |
1044 | ||
1045 | found: | |
1046 | vml = *parent; | |
1047 | ||
1048 | put_vma(vml->vma); | |
1049 | ||
1050 | *parent = vml->next; | |
1051 | realalloc -= kobjsize(vml); | |
1052 | askedalloc -= sizeof(*vml); | |
1053 | kfree(vml); | |
365e9c87 HD |
1054 | |
1055 | update_hiwater_vm(mm); | |
1da177e4 LT |
1056 | mm->total_vm -= len >> PAGE_SHIFT; |
1057 | ||
1058 | #ifdef DEBUG | |
1059 | show_process_blocks(); | |
1060 | #endif | |
1061 | ||
1062 | return 0; | |
1063 | } | |
1064 | ||
3034097a DH |
1065 | asmlinkage long sys_munmap(unsigned long addr, size_t len) |
1066 | { | |
1067 | int ret; | |
1068 | struct mm_struct *mm = current->mm; | |
1069 | ||
1070 | down_write(&mm->mmap_sem); | |
1071 | ret = do_munmap(mm, addr, len); | |
1072 | up_write(&mm->mmap_sem); | |
1073 | return ret; | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Release all mappings | |
1078 | */ | |
1da177e4 LT |
1079 | void exit_mmap(struct mm_struct * mm) |
1080 | { | |
1081 | struct vm_list_struct *tmp; | |
1082 | ||
1083 | if (mm) { | |
1084 | #ifdef DEBUG | |
1085 | printk("Exit_mmap:\n"); | |
1086 | #endif | |
1087 | ||
1088 | mm->total_vm = 0; | |
1089 | ||
1090 | while ((tmp = mm->context.vmlist)) { | |
1091 | mm->context.vmlist = tmp->next; | |
1092 | put_vma(tmp->vma); | |
1093 | ||
1094 | realalloc -= kobjsize(tmp); | |
1095 | askedalloc -= sizeof(*tmp); | |
1096 | kfree(tmp); | |
1097 | } | |
1098 | ||
1099 | #ifdef DEBUG | |
1100 | show_process_blocks(); | |
1101 | #endif | |
1102 | } | |
1103 | } | |
1104 | ||
1da177e4 LT |
1105 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1106 | { | |
1107 | return -ENOMEM; | |
1108 | } | |
1109 | ||
1110 | /* | |
6fa5f80b DH |
1111 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1112 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
1da177e4 | 1113 | * |
6fa5f80b DH |
1114 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
1115 | * as long as it stays within the hole allocated by the kmalloc() call in | |
1116 | * do_mmap_pgoff() and the block is not shareable | |
1da177e4 | 1117 | * |
6fa5f80b | 1118 | * MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4 LT |
1119 | */ |
1120 | unsigned long do_mremap(unsigned long addr, | |
1121 | unsigned long old_len, unsigned long new_len, | |
1122 | unsigned long flags, unsigned long new_addr) | |
1123 | { | |
6fa5f80b | 1124 | struct vm_area_struct *vma; |
1da177e4 LT |
1125 | |
1126 | /* insanity checks first */ | |
1127 | if (new_len == 0) | |
1128 | return (unsigned long) -EINVAL; | |
1129 | ||
1130 | if (flags & MREMAP_FIXED && new_addr != addr) | |
1131 | return (unsigned long) -EINVAL; | |
1132 | ||
6fa5f80b DH |
1133 | vma = find_vma_exact(current->mm, addr); |
1134 | if (!vma) | |
1135 | return (unsigned long) -EINVAL; | |
1da177e4 | 1136 | |
6fa5f80b | 1137 | if (vma->vm_end != vma->vm_start + old_len) |
1da177e4 LT |
1138 | return (unsigned long) -EFAULT; |
1139 | ||
6fa5f80b | 1140 | if (vma->vm_flags & VM_MAYSHARE) |
1da177e4 LT |
1141 | return (unsigned long) -EPERM; |
1142 | ||
1143 | if (new_len > kobjsize((void *) addr)) | |
1144 | return (unsigned long) -ENOMEM; | |
1145 | ||
1146 | /* all checks complete - do it */ | |
6fa5f80b | 1147 | vma->vm_end = vma->vm_start + new_len; |
1da177e4 LT |
1148 | |
1149 | askedalloc -= old_len; | |
1150 | askedalloc += new_len; | |
1151 | ||
6fa5f80b DH |
1152 | return vma->vm_start; |
1153 | } | |
1154 | ||
1155 | asmlinkage unsigned long sys_mremap(unsigned long addr, | |
1156 | unsigned long old_len, unsigned long new_len, | |
1157 | unsigned long flags, unsigned long new_addr) | |
1158 | { | |
1159 | unsigned long ret; | |
1160 | ||
1161 | down_write(¤t->mm->mmap_sem); | |
1162 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); | |
1163 | up_write(¤t->mm->mmap_sem); | |
1164 | return ret; | |
1da177e4 LT |
1165 | } |
1166 | ||
6aab341e | 1167 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1168 | unsigned int foll_flags) |
1da177e4 LT |
1169 | { |
1170 | return NULL; | |
1171 | } | |
1172 | ||
1da177e4 LT |
1173 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1174 | unsigned long to, unsigned long size, pgprot_t prot) | |
1175 | { | |
66aa2b4b GU |
1176 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1177 | return 0; | |
1da177e4 | 1178 | } |
22c4af40 | 1179 | EXPORT_SYMBOL(remap_pfn_range); |
1da177e4 LT |
1180 | |
1181 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) | |
1182 | { | |
1183 | } | |
1184 | ||
1185 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, | |
1186 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1187 | { | |
1188 | return -ENOMEM; | |
1189 | } | |
1190 | ||
1363c3cd | 1191 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1192 | { |
1193 | } | |
1194 | ||
1da177e4 LT |
1195 | void unmap_mapping_range(struct address_space *mapping, |
1196 | loff_t const holebegin, loff_t const holelen, | |
1197 | int even_cows) | |
1198 | { | |
1199 | } | |
22c4af40 | 1200 | EXPORT_SYMBOL(unmap_mapping_range); |
1da177e4 | 1201 | |
d56e03cd DH |
1202 | /* |
1203 | * ask for an unmapped area at which to create a mapping on a file | |
1204 | */ | |
1205 | unsigned long get_unmapped_area(struct file *file, unsigned long addr, | |
1206 | unsigned long len, unsigned long pgoff, | |
1207 | unsigned long flags) | |
1208 | { | |
1209 | unsigned long (*get_area)(struct file *, unsigned long, unsigned long, | |
1210 | unsigned long, unsigned long); | |
1211 | ||
1212 | get_area = current->mm->get_unmapped_area; | |
1213 | if (file && file->f_op && file->f_op->get_unmapped_area) | |
1214 | get_area = file->f_op->get_unmapped_area; | |
1215 | ||
1216 | if (!get_area) | |
1217 | return -ENOSYS; | |
1218 | ||
1219 | return get_area(file, addr, len, pgoff, flags); | |
1220 | } | |
1221 | ||
1222 | EXPORT_SYMBOL(get_unmapped_area); | |
1223 | ||
1da177e4 LT |
1224 | /* |
1225 | * Check that a process has enough memory to allocate a new virtual | |
1226 | * mapping. 0 means there is enough memory for the allocation to | |
1227 | * succeed and -ENOMEM implies there is not. | |
1228 | * | |
1229 | * We currently support three overcommit policies, which are set via the | |
1230 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
1231 | * | |
1232 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
1233 | * Additional code 2002 Jul 20 by Robert Love. | |
1234 | * | |
1235 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
1236 | * | |
1237 | * Note this is a helper function intended to be used by LSMs which | |
1238 | * wish to use this logic. | |
1239 | */ | |
1240 | int __vm_enough_memory(long pages, int cap_sys_admin) | |
1241 | { | |
1242 | unsigned long free, allowed; | |
1243 | ||
1244 | vm_acct_memory(pages); | |
1245 | ||
1246 | /* | |
1247 | * Sometimes we want to use more memory than we have | |
1248 | */ | |
1249 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
1250 | return 0; | |
1251 | ||
1252 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
1253 | unsigned long n; | |
1254 | ||
347ce434 | 1255 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
1256 | free += nr_swap_pages; |
1257 | ||
1258 | /* | |
1259 | * Any slabs which are created with the | |
1260 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
1261 | * which are reclaimable, under pressure. The dentry | |
1262 | * cache and most inode caches should fall into this | |
1263 | */ | |
972d1a7b | 1264 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
1265 | |
1266 | /* | |
1267 | * Leave the last 3% for root | |
1268 | */ | |
1269 | if (!cap_sys_admin) | |
1270 | free -= free / 32; | |
1271 | ||
1272 | if (free > pages) | |
1273 | return 0; | |
1274 | ||
1275 | /* | |
1276 | * nr_free_pages() is very expensive on large systems, | |
1277 | * only call if we're about to fail. | |
1278 | */ | |
1279 | n = nr_free_pages(); | |
d5ddc79b HA |
1280 | |
1281 | /* | |
1282 | * Leave reserved pages. The pages are not for anonymous pages. | |
1283 | */ | |
1284 | if (n <= totalreserve_pages) | |
1285 | goto error; | |
1286 | else | |
1287 | n -= totalreserve_pages; | |
1288 | ||
1289 | /* | |
1290 | * Leave the last 3% for root | |
1291 | */ | |
1da177e4 LT |
1292 | if (!cap_sys_admin) |
1293 | n -= n / 32; | |
1294 | free += n; | |
1295 | ||
1296 | if (free > pages) | |
1297 | return 0; | |
d5ddc79b HA |
1298 | |
1299 | goto error; | |
1da177e4 LT |
1300 | } |
1301 | ||
1302 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; | |
1303 | /* | |
1304 | * Leave the last 3% for root | |
1305 | */ | |
1306 | if (!cap_sys_admin) | |
1307 | allowed -= allowed / 32; | |
1308 | allowed += total_swap_pages; | |
1309 | ||
1310 | /* Don't let a single process grow too big: | |
1311 | leave 3% of the size of this process for other processes */ | |
1312 | allowed -= current->mm->total_vm / 32; | |
1313 | ||
2f60f8d3 SD |
1314 | /* |
1315 | * cast `allowed' as a signed long because vm_committed_space | |
1316 | * sometimes has a negative value | |
1317 | */ | |
1318 | if (atomic_read(&vm_committed_space) < (long)allowed) | |
1da177e4 | 1319 | return 0; |
d5ddc79b | 1320 | error: |
1da177e4 LT |
1321 | vm_unacct_memory(pages); |
1322 | ||
1323 | return -ENOMEM; | |
1324 | } | |
1325 | ||
1326 | int in_gate_area_no_task(unsigned long addr) | |
1327 | { | |
1328 | return 0; | |
1329 | } | |
b0e15190 DH |
1330 | |
1331 | struct page *filemap_nopage(struct vm_area_struct *area, | |
1332 | unsigned long address, int *type) | |
1333 | { | |
1334 | BUG(); | |
1335 | return NULL; | |
1336 | } | |
0ec76a11 DH |
1337 | |
1338 | /* | |
1339 | * Access another process' address space. | |
1340 | * - source/target buffer must be kernel space | |
1341 | */ | |
1342 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
1343 | { | |
0ec76a11 DH |
1344 | struct vm_area_struct *vma; |
1345 | struct mm_struct *mm; | |
1346 | ||
1347 | if (addr + len < addr) | |
1348 | return 0; | |
1349 | ||
1350 | mm = get_task_mm(tsk); | |
1351 | if (!mm) | |
1352 | return 0; | |
1353 | ||
1354 | down_read(&mm->mmap_sem); | |
1355 | ||
1356 | /* the access must start within one of the target process's mappings */ | |
0159b141 DH |
1357 | vma = find_vma(mm, addr); |
1358 | if (vma) { | |
0ec76a11 DH |
1359 | /* don't overrun this mapping */ |
1360 | if (addr + len >= vma->vm_end) | |
1361 | len = vma->vm_end - addr; | |
1362 | ||
1363 | /* only read or write mappings where it is permitted */ | |
d00c7b99 | 1364 | if (write && vma->vm_flags & VM_MAYWRITE) |
0ec76a11 | 1365 | len -= copy_to_user((void *) addr, buf, len); |
d00c7b99 | 1366 | else if (!write && vma->vm_flags & VM_MAYREAD) |
0ec76a11 DH |
1367 | len -= copy_from_user(buf, (void *) addr, len); |
1368 | else | |
1369 | len = 0; | |
1370 | } else { | |
1371 | len = 0; | |
1372 | } | |
1373 | ||
1374 | up_read(&mm->mmap_sem); | |
1375 | mmput(mm); | |
1376 | return len; | |
1377 | } |