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Commit | Line | Data |
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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 LT |
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 | ||
66aa2b4b GU |
56 | EXPORT_SYMBOL(vfree); |
57 | EXPORT_SYMBOL(vmalloc_to_page); | |
58 | EXPORT_SYMBOL(vmalloc_32); | |
7a9166e3 LY |
59 | EXPORT_SYMBOL(vmap); |
60 | EXPORT_SYMBOL(vunmap); | |
66aa2b4b | 61 | |
1da177e4 LT |
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 | /* | |
7b4d5b8b DH |
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 | |
1da177e4 LT |
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 | { | |
910e46da | 135 | struct vm_area_struct *vma; |
7b4d5b8b DH |
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); | |
1da177e4 LT |
144 | |
145 | for (i = 0; i < len; i++) { | |
910e46da | 146 | vma = find_vma(mm, start); |
7b4d5b8b DH |
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; | |
910e46da | 154 | |
1da177e4 LT |
155 | if (pages) { |
156 | pages[i] = virt_to_page(start); | |
157 | if (pages[i]) | |
158 | page_cache_get(pages[i]); | |
159 | } | |
160 | if (vmas) | |
910e46da | 161 | vmas[i] = vma; |
1da177e4 LT |
162 | start += PAGE_SIZE; |
163 | } | |
7b4d5b8b DH |
164 | |
165 | return i; | |
166 | ||
167 | finish_or_fault: | |
168 | return i ? : -EFAULT; | |
1da177e4 LT |
169 | } |
170 | ||
66aa2b4b GU |
171 | EXPORT_SYMBOL(get_user_pages); |
172 | ||
1da177e4 LT |
173 | DEFINE_RWLOCK(vmlist_lock); |
174 | struct vm_struct *vmlist; | |
175 | ||
176 | void vfree(void *addr) | |
177 | { | |
178 | kfree(addr); | |
179 | } | |
180 | ||
dd0fc66f | 181 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
1da177e4 LT |
182 | { |
183 | /* | |
184 | * kmalloc doesn't like __GFP_HIGHMEM for some reason | |
185 | */ | |
84097518 | 186 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
1da177e4 LT |
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 | * | |
c1c8897f | 224 | * For tight control over page level allocator and protection flags |
1da177e4 LT |
225 | * use __vmalloc() instead. |
226 | */ | |
227 | void *vmalloc(unsigned long size) | |
228 | { | |
229 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); | |
230 | } | |
f6138882 AM |
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); | |
1da177e4 LT |
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 | ||
3034097a DH |
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 | ||
930e652a DH |
352 | /* |
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 | ||
6fa5f80b DH |
361 | /* |
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 | ||
3034097a DH |
381 | /* |
382 | * find a VMA in the global tree | |
383 | */ | |
1da177e4 LT |
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 | ||
3034097a DH |
403 | /* |
404 | * add a VMA in the global tree | |
405 | */ | |
1da177e4 LT |
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 | ||
3034097a DH |
452 | /* |
453 | * delete a VMA from the global list | |
454 | */ | |
1da177e4 LT |
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 | ||
f81cff0d | 500 | if (!len) |
1da177e4 LT |
501 | return -EINVAL; |
502 | ||
f81cff0d MF |
503 | /* Careful about overflows.. */ |
504 | len = PAGE_ALIGN(len); | |
505 | if (!len || len > TASK_SIZE) | |
506 | return -ENOMEM; | |
507 | ||
1da177e4 LT |
508 | /* offset overflow? */ |
509 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
f81cff0d | 510 | return -EOVERFLOW; |
1da177e4 LT |
511 | |
512 | if (file) { | |
513 | /* validate file mapping requests */ | |
514 | struct address_space *mapping; | |
515 | ||
516 | /* files must support mmap */ | |
517 | if (!file->f_op || !file->f_op->mmap) | |
518 | return -ENODEV; | |
519 | ||
520 | /* work out if what we've got could possibly be shared | |
521 | * - we support chardevs that provide their own "memory" | |
522 | * - we support files/blockdevs that are memory backed | |
523 | */ | |
524 | mapping = file->f_mapping; | |
525 | if (!mapping) | |
e9536ae7 | 526 | mapping = file->f_path.dentry->d_inode->i_mapping; |
1da177e4 LT |
527 | |
528 | capabilities = 0; | |
529 | if (mapping && mapping->backing_dev_info) | |
530 | capabilities = mapping->backing_dev_info->capabilities; | |
531 | ||
532 | if (!capabilities) { | |
533 | /* no explicit capabilities set, so assume some | |
534 | * defaults */ | |
e9536ae7 | 535 | switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
1da177e4 LT |
536 | case S_IFREG: |
537 | case S_IFBLK: | |
538 | capabilities = BDI_CAP_MAP_COPY; | |
539 | break; | |
540 | ||
541 | case S_IFCHR: | |
542 | capabilities = | |
543 | BDI_CAP_MAP_DIRECT | | |
544 | BDI_CAP_READ_MAP | | |
545 | BDI_CAP_WRITE_MAP; | |
546 | break; | |
547 | ||
548 | default: | |
549 | return -EINVAL; | |
550 | } | |
551 | } | |
552 | ||
553 | /* eliminate any capabilities that we can't support on this | |
554 | * device */ | |
555 | if (!file->f_op->get_unmapped_area) | |
556 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
557 | if (!file->f_op->read) | |
558 | capabilities &= ~BDI_CAP_MAP_COPY; | |
559 | ||
560 | if (flags & MAP_SHARED) { | |
561 | /* do checks for writing, appending and locking */ | |
562 | if ((prot & PROT_WRITE) && | |
563 | !(file->f_mode & FMODE_WRITE)) | |
564 | return -EACCES; | |
565 | ||
e9536ae7 | 566 | if (IS_APPEND(file->f_path.dentry->d_inode) && |
1da177e4 LT |
567 | (file->f_mode & FMODE_WRITE)) |
568 | return -EACCES; | |
569 | ||
e9536ae7 | 570 | if (locks_verify_locked(file->f_path.dentry->d_inode)) |
1da177e4 LT |
571 | return -EAGAIN; |
572 | ||
573 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
574 | return -ENODEV; | |
575 | ||
576 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || | |
577 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || | |
578 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) | |
579 | ) { | |
580 | printk("MAP_SHARED not completely supported on !MMU\n"); | |
581 | return -EINVAL; | |
582 | } | |
583 | ||
584 | /* we mustn't privatise shared mappings */ | |
585 | capabilities &= ~BDI_CAP_MAP_COPY; | |
586 | } | |
587 | else { | |
588 | /* we're going to read the file into private memory we | |
589 | * allocate */ | |
590 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
591 | return -ENODEV; | |
592 | ||
593 | /* we don't permit a private writable mapping to be | |
594 | * shared with the backing device */ | |
595 | if (prot & PROT_WRITE) | |
596 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
597 | } | |
598 | ||
599 | /* handle executable mappings and implied executable | |
600 | * mappings */ | |
e9536ae7 | 601 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1da177e4 LT |
602 | if (prot & PROT_EXEC) |
603 | return -EPERM; | |
604 | } | |
605 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { | |
606 | /* handle implication of PROT_EXEC by PROT_READ */ | |
607 | if (current->personality & READ_IMPLIES_EXEC) { | |
608 | if (capabilities & BDI_CAP_EXEC_MAP) | |
609 | prot |= PROT_EXEC; | |
610 | } | |
611 | } | |
612 | else if ((prot & PROT_READ) && | |
613 | (prot & PROT_EXEC) && | |
614 | !(capabilities & BDI_CAP_EXEC_MAP) | |
615 | ) { | |
616 | /* backing file is not executable, try to copy */ | |
617 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
618 | } | |
619 | } | |
620 | else { | |
621 | /* anonymous mappings are always memory backed and can be | |
622 | * privately mapped | |
623 | */ | |
624 | capabilities = BDI_CAP_MAP_COPY; | |
625 | ||
626 | /* handle PROT_EXEC implication by PROT_READ */ | |
627 | if ((prot & PROT_READ) && | |
628 | (current->personality & READ_IMPLIES_EXEC)) | |
629 | prot |= PROT_EXEC; | |
630 | } | |
631 | ||
632 | /* allow the security API to have its say */ | |
633 | ret = security_file_mmap(file, reqprot, prot, flags); | |
634 | if (ret < 0) | |
635 | return ret; | |
636 | ||
637 | /* looks okay */ | |
638 | *_capabilities = capabilities; | |
639 | return 0; | |
640 | } | |
641 | ||
642 | /* | |
643 | * we've determined that we can make the mapping, now translate what we | |
644 | * now know into VMA flags | |
645 | */ | |
646 | static unsigned long determine_vm_flags(struct file *file, | |
647 | unsigned long prot, | |
648 | unsigned long flags, | |
649 | unsigned long capabilities) | |
650 | { | |
651 | unsigned long vm_flags; | |
652 | ||
653 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); | |
654 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
655 | /* vm_flags |= mm->def_flags; */ | |
656 | ||
657 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { | |
658 | /* attempt to share read-only copies of mapped file chunks */ | |
659 | if (file && !(prot & PROT_WRITE)) | |
660 | vm_flags |= VM_MAYSHARE; | |
661 | } | |
662 | else { | |
663 | /* overlay a shareable mapping on the backing device or inode | |
664 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and | |
665 | * romfs/cramfs */ | |
666 | if (flags & MAP_SHARED) | |
667 | vm_flags |= VM_MAYSHARE | VM_SHARED; | |
668 | else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0) | |
669 | vm_flags |= VM_MAYSHARE; | |
670 | } | |
671 | ||
672 | /* refuse to let anyone share private mappings with this process if | |
673 | * it's being traced - otherwise breakpoints set in it may interfere | |
674 | * with another untraced process | |
675 | */ | |
676 | if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED)) | |
677 | vm_flags &= ~VM_MAYSHARE; | |
678 | ||
679 | return vm_flags; | |
680 | } | |
681 | ||
682 | /* | |
683 | * set up a shared mapping on a file | |
684 | */ | |
685 | static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len) | |
686 | { | |
687 | int ret; | |
688 | ||
689 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
690 | if (ret != -ENOSYS) | |
691 | return ret; | |
692 | ||
693 | /* getting an ENOSYS error indicates that direct mmap isn't | |
694 | * possible (as opposed to tried but failed) so we'll fall | |
695 | * through to making a private copy of the data and mapping | |
696 | * that if we can */ | |
697 | return -ENODEV; | |
698 | } | |
699 | ||
700 | /* | |
701 | * set up a private mapping or an anonymous shared mapping | |
702 | */ | |
703 | static int do_mmap_private(struct vm_area_struct *vma, unsigned long len) | |
704 | { | |
705 | void *base; | |
706 | int ret; | |
707 | ||
708 | /* invoke the file's mapping function so that it can keep track of | |
709 | * shared mappings on devices or memory | |
710 | * - VM_MAYSHARE will be set if it may attempt to share | |
711 | */ | |
712 | if (vma->vm_file) { | |
713 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
714 | if (ret != -ENOSYS) { | |
715 | /* shouldn't return success if we're not sharing */ | |
716 | BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE)); | |
717 | return ret; /* success or a real error */ | |
718 | } | |
719 | ||
720 | /* getting an ENOSYS error indicates that direct mmap isn't | |
721 | * possible (as opposed to tried but failed) so we'll try to | |
722 | * make a private copy of the data and map that instead */ | |
723 | } | |
724 | ||
725 | /* allocate some memory to hold the mapping | |
726 | * - note that this may not return a page-aligned address if the object | |
727 | * we're allocating is smaller than a page | |
728 | */ | |
84097518 | 729 | base = kmalloc(len, GFP_KERNEL|__GFP_COMP); |
1da177e4 LT |
730 | if (!base) |
731 | goto enomem; | |
732 | ||
733 | vma->vm_start = (unsigned long) base; | |
734 | vma->vm_end = vma->vm_start + len; | |
735 | vma->vm_flags |= VM_MAPPED_COPY; | |
736 | ||
737 | #ifdef WARN_ON_SLACK | |
738 | if (len + WARN_ON_SLACK <= kobjsize(result)) | |
739 | printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n", | |
740 | len, current->pid, kobjsize(result) - len); | |
741 | #endif | |
742 | ||
743 | if (vma->vm_file) { | |
744 | /* read the contents of a file into the copy */ | |
745 | mm_segment_t old_fs; | |
746 | loff_t fpos; | |
747 | ||
748 | fpos = vma->vm_pgoff; | |
749 | fpos <<= PAGE_SHIFT; | |
750 | ||
751 | old_fs = get_fs(); | |
752 | set_fs(KERNEL_DS); | |
753 | ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); | |
754 | set_fs(old_fs); | |
755 | ||
756 | if (ret < 0) | |
757 | goto error_free; | |
758 | ||
759 | /* clear the last little bit */ | |
760 | if (ret < len) | |
761 | memset(base + ret, 0, len - ret); | |
762 | ||
763 | } else { | |
764 | /* if it's an anonymous mapping, then just clear it */ | |
765 | memset(base, 0, len); | |
766 | } | |
767 | ||
768 | return 0; | |
769 | ||
770 | error_free: | |
771 | kfree(base); | |
772 | vma->vm_start = 0; | |
773 | return ret; | |
774 | ||
775 | enomem: | |
776 | printk("Allocation of length %lu from process %d failed\n", | |
777 | len, current->pid); | |
778 | show_free_areas(); | |
779 | return -ENOMEM; | |
780 | } | |
781 | ||
782 | /* | |
783 | * handle mapping creation for uClinux | |
784 | */ | |
785 | unsigned long do_mmap_pgoff(struct file *file, | |
786 | unsigned long addr, | |
787 | unsigned long len, | |
788 | unsigned long prot, | |
789 | unsigned long flags, | |
790 | unsigned long pgoff) | |
791 | { | |
792 | struct vm_list_struct *vml = NULL; | |
793 | struct vm_area_struct *vma = NULL; | |
794 | struct rb_node *rb; | |
795 | unsigned long capabilities, vm_flags; | |
796 | void *result; | |
797 | int ret; | |
798 | ||
799 | /* decide whether we should attempt the mapping, and if so what sort of | |
800 | * mapping */ | |
801 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, | |
802 | &capabilities); | |
803 | if (ret < 0) | |
804 | return ret; | |
805 | ||
806 | /* we've determined that we can make the mapping, now translate what we | |
807 | * now know into VMA flags */ | |
808 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); | |
809 | ||
810 | /* we're going to need to record the mapping if it works */ | |
4668edc3 | 811 | vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL); |
1da177e4 LT |
812 | if (!vml) |
813 | goto error_getting_vml; | |
1da177e4 LT |
814 | |
815 | down_write(&nommu_vma_sem); | |
816 | ||
817 | /* if we want to share, we need to check for VMAs created by other | |
818 | * mmap() calls that overlap with our proposed mapping | |
819 | * - we can only share with an exact match on most regular files | |
820 | * - shared mappings on character devices and memory backed files are | |
821 | * permitted to overlap inexactly as far as we are concerned for in | |
822 | * these cases, sharing is handled in the driver or filesystem rather | |
823 | * than here | |
824 | */ | |
825 | if (vm_flags & VM_MAYSHARE) { | |
826 | unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
827 | unsigned long vmpglen; | |
828 | ||
829 | for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) { | |
830 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); | |
831 | ||
832 | if (!(vma->vm_flags & VM_MAYSHARE)) | |
833 | continue; | |
834 | ||
835 | /* search for overlapping mappings on the same file */ | |
e9536ae7 | 836 | if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode) |
1da177e4 LT |
837 | continue; |
838 | ||
839 | if (vma->vm_pgoff >= pgoff + pglen) | |
840 | continue; | |
841 | ||
842 | vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1; | |
843 | vmpglen >>= PAGE_SHIFT; | |
844 | if (pgoff >= vma->vm_pgoff + vmpglen) | |
845 | continue; | |
846 | ||
847 | /* handle inexactly overlapping matches between mappings */ | |
848 | if (vma->vm_pgoff != pgoff || vmpglen != pglen) { | |
849 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
850 | goto sharing_violation; | |
851 | continue; | |
852 | } | |
853 | ||
854 | /* we've found a VMA we can share */ | |
855 | atomic_inc(&vma->vm_usage); | |
856 | ||
857 | vml->vma = vma; | |
858 | result = (void *) vma->vm_start; | |
859 | goto shared; | |
860 | } | |
861 | ||
862 | vma = NULL; | |
863 | ||
864 | /* obtain the address at which to make a shared mapping | |
865 | * - this is the hook for quasi-memory character devices to | |
866 | * tell us the location of a shared mapping | |
867 | */ | |
868 | if (file && file->f_op->get_unmapped_area) { | |
869 | addr = file->f_op->get_unmapped_area(file, addr, len, | |
870 | pgoff, flags); | |
871 | if (IS_ERR((void *) addr)) { | |
872 | ret = addr; | |
873 | if (ret != (unsigned long) -ENOSYS) | |
874 | goto error; | |
875 | ||
876 | /* the driver refused to tell us where to site | |
877 | * the mapping so we'll have to attempt to copy | |
878 | * it */ | |
879 | ret = (unsigned long) -ENODEV; | |
880 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
881 | goto error; | |
882 | ||
883 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
884 | } | |
885 | } | |
886 | } | |
887 | ||
888 | /* we're going to need a VMA struct as well */ | |
4668edc3 | 889 | vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL); |
1da177e4 LT |
890 | if (!vma) |
891 | goto error_getting_vma; | |
892 | ||
1da177e4 LT |
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 | ||
3034097a | 932 | add_vma_to_mm(current->mm, vml); |
1da177e4 LT |
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) { | |
3fcd03e0 GL |
951 | if (vma->vm_file) |
952 | fput(vma->vm_file); | |
1da177e4 LT |
953 | kfree(vma); |
954 | } | |
955 | return ret; | |
956 | ||
957 | sharing_violation: | |
958 | up_write(&nommu_vma_sem); | |
959 | printk("Attempt to share mismatched mappings\n"); | |
960 | kfree(vml); | |
961 | return -EINVAL; | |
962 | ||
963 | error_getting_vma: | |
964 | up_write(&nommu_vma_sem); | |
965 | kfree(vml); | |
66aa2b4b | 966 | printk("Allocation of vma for %lu byte allocation from process %d failed\n", |
1da177e4 LT |
967 | len, current->pid); |
968 | show_free_areas(); | |
969 | return -ENOMEM; | |
970 | ||
971 | error_getting_vml: | |
972 | printk("Allocation of vml for %lu byte allocation from process %d failed\n", | |
973 | len, current->pid); | |
974 | show_free_areas(); | |
975 | return -ENOMEM; | |
976 | } | |
977 | ||
978 | /* | |
979 | * handle mapping disposal for uClinux | |
980 | */ | |
981 | static void put_vma(struct vm_area_struct *vma) | |
982 | { | |
983 | if (vma) { | |
984 | down_write(&nommu_vma_sem); | |
985 | ||
986 | if (atomic_dec_and_test(&vma->vm_usage)) { | |
987 | delete_nommu_vma(vma); | |
988 | ||
989 | if (vma->vm_ops && vma->vm_ops->close) | |
990 | vma->vm_ops->close(vma); | |
991 | ||
992 | /* IO memory and memory shared directly out of the pagecache from | |
993 | * ramfs/tmpfs mustn't be released here */ | |
994 | if (vma->vm_flags & VM_MAPPED_COPY) { | |
995 | realalloc -= kobjsize((void *) vma->vm_start); | |
996 | askedalloc -= vma->vm_end - vma->vm_start; | |
997 | kfree((void *) vma->vm_start); | |
998 | } | |
999 | ||
1000 | realalloc -= kobjsize(vma); | |
1001 | askedalloc -= sizeof(*vma); | |
1002 | ||
1003 | if (vma->vm_file) | |
1004 | fput(vma->vm_file); | |
1005 | kfree(vma); | |
1006 | } | |
1007 | ||
1008 | up_write(&nommu_vma_sem); | |
1009 | } | |
1010 | } | |
1011 | ||
3034097a DH |
1012 | /* |
1013 | * release a mapping | |
1014 | * - under NOMMU conditions the parameters must match exactly to the mapping to | |
1015 | * be removed | |
1016 | */ | |
1da177e4 LT |
1017 | int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) |
1018 | { | |
1019 | struct vm_list_struct *vml, **parent; | |
1020 | unsigned long end = addr + len; | |
1021 | ||
1022 | #ifdef DEBUG | |
1023 | printk("do_munmap:\n"); | |
1024 | #endif | |
1025 | ||
3034097a DH |
1026 | for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) { |
1027 | if ((*parent)->vma->vm_start > addr) | |
1028 | break; | |
1da177e4 | 1029 | if ((*parent)->vma->vm_start == addr && |
66aa2b4b | 1030 | ((len == 0) || ((*parent)->vma->vm_end == end))) |
1da177e4 | 1031 | goto found; |
3034097a | 1032 | } |
1da177e4 LT |
1033 | |
1034 | printk("munmap of non-mmaped memory by process %d (%s): %p\n", | |
1035 | current->pid, current->comm, (void *) addr); | |
1036 | return -EINVAL; | |
1037 | ||
1038 | found: | |
1039 | vml = *parent; | |
1040 | ||
1041 | put_vma(vml->vma); | |
1042 | ||
1043 | *parent = vml->next; | |
1044 | realalloc -= kobjsize(vml); | |
1045 | askedalloc -= sizeof(*vml); | |
1046 | kfree(vml); | |
365e9c87 HD |
1047 | |
1048 | update_hiwater_vm(mm); | |
1da177e4 LT |
1049 | mm->total_vm -= len >> PAGE_SHIFT; |
1050 | ||
1051 | #ifdef DEBUG | |
1052 | show_process_blocks(); | |
1053 | #endif | |
1054 | ||
1055 | return 0; | |
1056 | } | |
1057 | ||
3034097a DH |
1058 | asmlinkage long sys_munmap(unsigned long addr, size_t len) |
1059 | { | |
1060 | int ret; | |
1061 | struct mm_struct *mm = current->mm; | |
1062 | ||
1063 | down_write(&mm->mmap_sem); | |
1064 | ret = do_munmap(mm, addr, len); | |
1065 | up_write(&mm->mmap_sem); | |
1066 | return ret; | |
1067 | } | |
1068 | ||
1069 | /* | |
1070 | * Release all mappings | |
1071 | */ | |
1da177e4 LT |
1072 | void exit_mmap(struct mm_struct * mm) |
1073 | { | |
1074 | struct vm_list_struct *tmp; | |
1075 | ||
1076 | if (mm) { | |
1077 | #ifdef DEBUG | |
1078 | printk("Exit_mmap:\n"); | |
1079 | #endif | |
1080 | ||
1081 | mm->total_vm = 0; | |
1082 | ||
1083 | while ((tmp = mm->context.vmlist)) { | |
1084 | mm->context.vmlist = tmp->next; | |
1085 | put_vma(tmp->vma); | |
1086 | ||
1087 | realalloc -= kobjsize(tmp); | |
1088 | askedalloc -= sizeof(*tmp); | |
1089 | kfree(tmp); | |
1090 | } | |
1091 | ||
1092 | #ifdef DEBUG | |
1093 | show_process_blocks(); | |
1094 | #endif | |
1095 | } | |
1096 | } | |
1097 | ||
1da177e4 LT |
1098 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1099 | { | |
1100 | return -ENOMEM; | |
1101 | } | |
1102 | ||
1103 | /* | |
6fa5f80b DH |
1104 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1105 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
1da177e4 | 1106 | * |
6fa5f80b DH |
1107 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
1108 | * as long as it stays within the hole allocated by the kmalloc() call in | |
1109 | * do_mmap_pgoff() and the block is not shareable | |
1da177e4 | 1110 | * |
6fa5f80b | 1111 | * MREMAP_FIXED is not supported under NOMMU conditions |
1da177e4 LT |
1112 | */ |
1113 | unsigned long do_mremap(unsigned long addr, | |
1114 | unsigned long old_len, unsigned long new_len, | |
1115 | unsigned long flags, unsigned long new_addr) | |
1116 | { | |
6fa5f80b | 1117 | struct vm_area_struct *vma; |
1da177e4 LT |
1118 | |
1119 | /* insanity checks first */ | |
1120 | if (new_len == 0) | |
1121 | return (unsigned long) -EINVAL; | |
1122 | ||
1123 | if (flags & MREMAP_FIXED && new_addr != addr) | |
1124 | return (unsigned long) -EINVAL; | |
1125 | ||
6fa5f80b DH |
1126 | vma = find_vma_exact(current->mm, addr); |
1127 | if (!vma) | |
1128 | return (unsigned long) -EINVAL; | |
1da177e4 | 1129 | |
6fa5f80b | 1130 | if (vma->vm_end != vma->vm_start + old_len) |
1da177e4 LT |
1131 | return (unsigned long) -EFAULT; |
1132 | ||
6fa5f80b | 1133 | if (vma->vm_flags & VM_MAYSHARE) |
1da177e4 LT |
1134 | return (unsigned long) -EPERM; |
1135 | ||
1136 | if (new_len > kobjsize((void *) addr)) | |
1137 | return (unsigned long) -ENOMEM; | |
1138 | ||
1139 | /* all checks complete - do it */ | |
6fa5f80b | 1140 | vma->vm_end = vma->vm_start + new_len; |
1da177e4 LT |
1141 | |
1142 | askedalloc -= old_len; | |
1143 | askedalloc += new_len; | |
1144 | ||
6fa5f80b DH |
1145 | return vma->vm_start; |
1146 | } | |
1147 | ||
1148 | asmlinkage unsigned long sys_mremap(unsigned long addr, | |
1149 | unsigned long old_len, unsigned long new_len, | |
1150 | unsigned long flags, unsigned long new_addr) | |
1151 | { | |
1152 | unsigned long ret; | |
1153 | ||
1154 | down_write(¤t->mm->mmap_sem); | |
1155 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); | |
1156 | up_write(¤t->mm->mmap_sem); | |
1157 | return ret; | |
1da177e4 LT |
1158 | } |
1159 | ||
6aab341e | 1160 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1161 | unsigned int foll_flags) |
1da177e4 LT |
1162 | { |
1163 | return NULL; | |
1164 | } | |
1165 | ||
1da177e4 LT |
1166 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1167 | unsigned long to, unsigned long size, pgprot_t prot) | |
1168 | { | |
66aa2b4b GU |
1169 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1170 | return 0; | |
1da177e4 | 1171 | } |
22c4af40 | 1172 | EXPORT_SYMBOL(remap_pfn_range); |
1da177e4 LT |
1173 | |
1174 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) | |
1175 | { | |
1176 | } | |
1177 | ||
1178 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, | |
1179 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1180 | { | |
1181 | return -ENOMEM; | |
1182 | } | |
1183 | ||
1363c3cd | 1184 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1185 | { |
1186 | } | |
1187 | ||
1da177e4 LT |
1188 | void unmap_mapping_range(struct address_space *mapping, |
1189 | loff_t const holebegin, loff_t const holelen, | |
1190 | int even_cows) | |
1191 | { | |
1192 | } | |
22c4af40 | 1193 | EXPORT_SYMBOL(unmap_mapping_range); |
1da177e4 LT |
1194 | |
1195 | /* | |
1196 | * Check that a process has enough memory to allocate a new virtual | |
1197 | * mapping. 0 means there is enough memory for the allocation to | |
1198 | * succeed and -ENOMEM implies there is not. | |
1199 | * | |
1200 | * We currently support three overcommit policies, which are set via the | |
1201 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
1202 | * | |
1203 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
1204 | * Additional code 2002 Jul 20 by Robert Love. | |
1205 | * | |
1206 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
1207 | * | |
1208 | * Note this is a helper function intended to be used by LSMs which | |
1209 | * wish to use this logic. | |
1210 | */ | |
1211 | int __vm_enough_memory(long pages, int cap_sys_admin) | |
1212 | { | |
1213 | unsigned long free, allowed; | |
1214 | ||
1215 | vm_acct_memory(pages); | |
1216 | ||
1217 | /* | |
1218 | * Sometimes we want to use more memory than we have | |
1219 | */ | |
1220 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
1221 | return 0; | |
1222 | ||
1223 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
1224 | unsigned long n; | |
1225 | ||
347ce434 | 1226 | free = global_page_state(NR_FILE_PAGES); |
1da177e4 LT |
1227 | free += nr_swap_pages; |
1228 | ||
1229 | /* | |
1230 | * Any slabs which are created with the | |
1231 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
1232 | * which are reclaimable, under pressure. The dentry | |
1233 | * cache and most inode caches should fall into this | |
1234 | */ | |
972d1a7b | 1235 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1da177e4 LT |
1236 | |
1237 | /* | |
1238 | * Leave the last 3% for root | |
1239 | */ | |
1240 | if (!cap_sys_admin) | |
1241 | free -= free / 32; | |
1242 | ||
1243 | if (free > pages) | |
1244 | return 0; | |
1245 | ||
1246 | /* | |
1247 | * nr_free_pages() is very expensive on large systems, | |
1248 | * only call if we're about to fail. | |
1249 | */ | |
1250 | n = nr_free_pages(); | |
d5ddc79b HA |
1251 | |
1252 | /* | |
1253 | * Leave reserved pages. The pages are not for anonymous pages. | |
1254 | */ | |
1255 | if (n <= totalreserve_pages) | |
1256 | goto error; | |
1257 | else | |
1258 | n -= totalreserve_pages; | |
1259 | ||
1260 | /* | |
1261 | * Leave the last 3% for root | |
1262 | */ | |
1da177e4 LT |
1263 | if (!cap_sys_admin) |
1264 | n -= n / 32; | |
1265 | free += n; | |
1266 | ||
1267 | if (free > pages) | |
1268 | return 0; | |
d5ddc79b HA |
1269 | |
1270 | goto error; | |
1da177e4 LT |
1271 | } |
1272 | ||
1273 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; | |
1274 | /* | |
1275 | * Leave the last 3% for root | |
1276 | */ | |
1277 | if (!cap_sys_admin) | |
1278 | allowed -= allowed / 32; | |
1279 | allowed += total_swap_pages; | |
1280 | ||
1281 | /* Don't let a single process grow too big: | |
1282 | leave 3% of the size of this process for other processes */ | |
1283 | allowed -= current->mm->total_vm / 32; | |
1284 | ||
2f60f8d3 SD |
1285 | /* |
1286 | * cast `allowed' as a signed long because vm_committed_space | |
1287 | * sometimes has a negative value | |
1288 | */ | |
1289 | if (atomic_read(&vm_committed_space) < (long)allowed) | |
1da177e4 | 1290 | return 0; |
d5ddc79b | 1291 | error: |
1da177e4 LT |
1292 | vm_unacct_memory(pages); |
1293 | ||
1294 | return -ENOMEM; | |
1295 | } | |
1296 | ||
1297 | int in_gate_area_no_task(unsigned long addr) | |
1298 | { | |
1299 | return 0; | |
1300 | } | |
b0e15190 DH |
1301 | |
1302 | struct page *filemap_nopage(struct vm_area_struct *area, | |
1303 | unsigned long address, int *type) | |
1304 | { | |
1305 | BUG(); | |
1306 | return NULL; | |
1307 | } | |
0ec76a11 DH |
1308 | |
1309 | /* | |
1310 | * Access another process' address space. | |
1311 | * - source/target buffer must be kernel space | |
1312 | */ | |
1313 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
1314 | { | |
0ec76a11 DH |
1315 | struct vm_area_struct *vma; |
1316 | struct mm_struct *mm; | |
1317 | ||
1318 | if (addr + len < addr) | |
1319 | return 0; | |
1320 | ||
1321 | mm = get_task_mm(tsk); | |
1322 | if (!mm) | |
1323 | return 0; | |
1324 | ||
1325 | down_read(&mm->mmap_sem); | |
1326 | ||
1327 | /* the access must start within one of the target process's mappings */ | |
0159b141 DH |
1328 | vma = find_vma(mm, addr); |
1329 | if (vma) { | |
0ec76a11 DH |
1330 | /* don't overrun this mapping */ |
1331 | if (addr + len >= vma->vm_end) | |
1332 | len = vma->vm_end - addr; | |
1333 | ||
1334 | /* only read or write mappings where it is permitted */ | |
d00c7b99 | 1335 | if (write && vma->vm_flags & VM_MAYWRITE) |
0ec76a11 | 1336 | len -= copy_to_user((void *) addr, buf, len); |
d00c7b99 | 1337 | else if (!write && vma->vm_flags & VM_MAYREAD) |
0ec76a11 DH |
1338 | len -= copy_from_user(buf, (void *) addr, len); |
1339 | else | |
1340 | len = 0; | |
1341 | } else { | |
1342 | len = 0; | |
1343 | } | |
1344 | ||
1345 | up_read(&mm->mmap_sem); | |
1346 | mmput(mm); | |
1347 | return len; | |
1348 | } |