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); | |
47 | EXPORT_SYMBOL(sysctl_max_map_count); | |
48 | EXPORT_SYMBOL(sysctl_overcommit_memory); | |
49 | EXPORT_SYMBOL(sysctl_overcommit_ratio); | |
50 | EXPORT_SYMBOL(vm_committed_space); | |
51 | EXPORT_SYMBOL(__vm_enough_memory); | |
52 | ||
53 | /* list of shareable VMAs */ | |
54 | struct rb_root nommu_vma_tree = RB_ROOT; | |
55 | DECLARE_RWSEM(nommu_vma_sem); | |
56 | ||
57 | struct vm_operations_struct generic_file_vm_ops = { | |
58 | }; | |
59 | ||
60 | /* | |
61 | * Handle all mappings that got truncated by a "truncate()" | |
62 | * system call. | |
63 | * | |
64 | * NOTE! We have to be ready to update the memory sharing | |
65 | * between the file and the memory map for a potential last | |
66 | * incomplete page. Ugly, but necessary. | |
67 | */ | |
68 | int vmtruncate(struct inode *inode, loff_t offset) | |
69 | { | |
70 | struct address_space *mapping = inode->i_mapping; | |
71 | unsigned long limit; | |
72 | ||
73 | if (inode->i_size < offset) | |
74 | goto do_expand; | |
75 | i_size_write(inode, offset); | |
76 | ||
77 | truncate_inode_pages(mapping, offset); | |
78 | goto out_truncate; | |
79 | ||
80 | do_expand: | |
81 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
82 | if (limit != RLIM_INFINITY && offset > limit) | |
83 | goto out_sig; | |
84 | if (offset > inode->i_sb->s_maxbytes) | |
85 | goto out; | |
86 | i_size_write(inode, offset); | |
87 | ||
88 | out_truncate: | |
89 | if (inode->i_op && inode->i_op->truncate) | |
90 | inode->i_op->truncate(inode); | |
91 | return 0; | |
92 | out_sig: | |
93 | send_sig(SIGXFSZ, current, 0); | |
94 | out: | |
95 | return -EFBIG; | |
96 | } | |
97 | ||
98 | EXPORT_SYMBOL(vmtruncate); | |
99 | ||
100 | /* | |
101 | * Return the total memory allocated for this pointer, not | |
102 | * just what the caller asked for. | |
103 | * | |
104 | * Doesn't have to be accurate, i.e. may have races. | |
105 | */ | |
106 | unsigned int kobjsize(const void *objp) | |
107 | { | |
108 | struct page *page; | |
109 | ||
110 | if (!objp || !((page = virt_to_page(objp)))) | |
111 | return 0; | |
112 | ||
113 | if (PageSlab(page)) | |
114 | return ksize(objp); | |
115 | ||
116 | BUG_ON(page->index < 0); | |
117 | BUG_ON(page->index >= MAX_ORDER); | |
118 | ||
119 | return (PAGE_SIZE << page->index); | |
120 | } | |
121 | ||
122 | /* | |
123 | * The nommu dodgy version :-) | |
124 | */ | |
125 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
126 | unsigned long start, int len, int write, int force, | |
127 | struct page **pages, struct vm_area_struct **vmas) | |
128 | { | |
129 | int i; | |
130 | static struct vm_area_struct dummy_vma; | |
131 | ||
132 | for (i = 0; i < len; i++) { | |
133 | if (pages) { | |
134 | pages[i] = virt_to_page(start); | |
135 | if (pages[i]) | |
136 | page_cache_get(pages[i]); | |
137 | } | |
138 | if (vmas) | |
139 | vmas[i] = &dummy_vma; | |
140 | start += PAGE_SIZE; | |
141 | } | |
142 | return(i); | |
143 | } | |
144 | ||
145 | DEFINE_RWLOCK(vmlist_lock); | |
146 | struct vm_struct *vmlist; | |
147 | ||
148 | void vfree(void *addr) | |
149 | { | |
150 | kfree(addr); | |
151 | } | |
152 | ||
7a019225 AB |
153 | void *__vmalloc(unsigned long size, unsigned int __nocast gfp_mask, |
154 | pgprot_t prot) | |
1da177e4 LT |
155 | { |
156 | /* | |
157 | * kmalloc doesn't like __GFP_HIGHMEM for some reason | |
158 | */ | |
159 | return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM); | |
160 | } | |
161 | ||
162 | struct page * vmalloc_to_page(void *addr) | |
163 | { | |
164 | return virt_to_page(addr); | |
165 | } | |
166 | ||
167 | unsigned long vmalloc_to_pfn(void *addr) | |
168 | { | |
169 | return page_to_pfn(virt_to_page(addr)); | |
170 | } | |
171 | ||
172 | ||
173 | long vread(char *buf, char *addr, unsigned long count) | |
174 | { | |
175 | memcpy(buf, addr, count); | |
176 | return count; | |
177 | } | |
178 | ||
179 | long vwrite(char *buf, char *addr, unsigned long count) | |
180 | { | |
181 | /* Don't allow overflow */ | |
182 | if ((unsigned long) addr + count < count) | |
183 | count = -(unsigned long) addr; | |
184 | ||
185 | memcpy(addr, buf, count); | |
186 | return(count); | |
187 | } | |
188 | ||
189 | /* | |
190 | * vmalloc - allocate virtually continguos memory | |
191 | * | |
192 | * @size: allocation size | |
193 | * | |
194 | * Allocate enough pages to cover @size from the page level | |
195 | * allocator and map them into continguos kernel virtual space. | |
196 | * | |
197 | * For tight cotrol over page level allocator and protection flags | |
198 | * use __vmalloc() instead. | |
199 | */ | |
200 | void *vmalloc(unsigned long size) | |
201 | { | |
202 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); | |
203 | } | |
204 | ||
205 | /* | |
206 | * vmalloc_32 - allocate virtually continguos memory (32bit addressable) | |
207 | * | |
208 | * @size: allocation size | |
209 | * | |
210 | * Allocate enough 32bit PA addressable pages to cover @size from the | |
211 | * page level allocator and map them into continguos kernel virtual space. | |
212 | */ | |
213 | void *vmalloc_32(unsigned long size) | |
214 | { | |
215 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); | |
216 | } | |
217 | ||
218 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) | |
219 | { | |
220 | BUG(); | |
221 | return NULL; | |
222 | } | |
223 | ||
224 | void vunmap(void *addr) | |
225 | { | |
226 | BUG(); | |
227 | } | |
228 | ||
229 | /* | |
230 | * sys_brk() for the most part doesn't need the global kernel | |
231 | * lock, except when an application is doing something nasty | |
232 | * like trying to un-brk an area that has already been mapped | |
233 | * to a regular file. in this case, the unmapping will need | |
234 | * to invoke file system routines that need the global lock. | |
235 | */ | |
236 | asmlinkage unsigned long sys_brk(unsigned long brk) | |
237 | { | |
238 | struct mm_struct *mm = current->mm; | |
239 | ||
240 | if (brk < mm->start_brk || brk > mm->context.end_brk) | |
241 | return mm->brk; | |
242 | ||
243 | if (mm->brk == brk) | |
244 | return mm->brk; | |
245 | ||
246 | /* | |
247 | * Always allow shrinking brk | |
248 | */ | |
249 | if (brk <= mm->brk) { | |
250 | mm->brk = brk; | |
251 | return brk; | |
252 | } | |
253 | ||
254 | /* | |
255 | * Ok, looks good - let it rip. | |
256 | */ | |
257 | return mm->brk = brk; | |
258 | } | |
259 | ||
260 | #ifdef DEBUG | |
261 | static void show_process_blocks(void) | |
262 | { | |
263 | struct vm_list_struct *vml; | |
264 | ||
265 | printk("Process blocks %d:", current->pid); | |
266 | ||
267 | for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) { | |
268 | printk(" %p: %p", vml, vml->vma); | |
269 | if (vml->vma) | |
270 | printk(" (%d @%lx #%d)", | |
271 | kobjsize((void *) vml->vma->vm_start), | |
272 | vml->vma->vm_start, | |
273 | atomic_read(&vml->vma->vm_usage)); | |
274 | printk(vml->next ? " ->" : ".\n"); | |
275 | } | |
276 | } | |
277 | #endif /* DEBUG */ | |
278 | ||
279 | static inline struct vm_area_struct *find_nommu_vma(unsigned long start) | |
280 | { | |
281 | struct vm_area_struct *vma; | |
282 | struct rb_node *n = nommu_vma_tree.rb_node; | |
283 | ||
284 | while (n) { | |
285 | vma = rb_entry(n, struct vm_area_struct, vm_rb); | |
286 | ||
287 | if (start < vma->vm_start) | |
288 | n = n->rb_left; | |
289 | else if (start > vma->vm_start) | |
290 | n = n->rb_right; | |
291 | else | |
292 | return vma; | |
293 | } | |
294 | ||
295 | return NULL; | |
296 | } | |
297 | ||
298 | static void add_nommu_vma(struct vm_area_struct *vma) | |
299 | { | |
300 | struct vm_area_struct *pvma; | |
301 | struct address_space *mapping; | |
302 | struct rb_node **p = &nommu_vma_tree.rb_node; | |
303 | struct rb_node *parent = NULL; | |
304 | ||
305 | /* add the VMA to the mapping */ | |
306 | if (vma->vm_file) { | |
307 | mapping = vma->vm_file->f_mapping; | |
308 | ||
309 | flush_dcache_mmap_lock(mapping); | |
310 | vma_prio_tree_insert(vma, &mapping->i_mmap); | |
311 | flush_dcache_mmap_unlock(mapping); | |
312 | } | |
313 | ||
314 | /* add the VMA to the master list */ | |
315 | while (*p) { | |
316 | parent = *p; | |
317 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); | |
318 | ||
319 | if (vma->vm_start < pvma->vm_start) { | |
320 | p = &(*p)->rb_left; | |
321 | } | |
322 | else if (vma->vm_start > pvma->vm_start) { | |
323 | p = &(*p)->rb_right; | |
324 | } | |
325 | else { | |
326 | /* mappings are at the same address - this can only | |
327 | * happen for shared-mem chardevs and shared file | |
328 | * mappings backed by ramfs/tmpfs */ | |
329 | BUG_ON(!(pvma->vm_flags & VM_SHARED)); | |
330 | ||
331 | if (vma < pvma) | |
332 | p = &(*p)->rb_left; | |
333 | else if (vma > pvma) | |
334 | p = &(*p)->rb_right; | |
335 | else | |
336 | BUG(); | |
337 | } | |
338 | } | |
339 | ||
340 | rb_link_node(&vma->vm_rb, parent, p); | |
341 | rb_insert_color(&vma->vm_rb, &nommu_vma_tree); | |
342 | } | |
343 | ||
344 | static void delete_nommu_vma(struct vm_area_struct *vma) | |
345 | { | |
346 | struct address_space *mapping; | |
347 | ||
348 | /* remove the VMA from the mapping */ | |
349 | if (vma->vm_file) { | |
350 | mapping = vma->vm_file->f_mapping; | |
351 | ||
352 | flush_dcache_mmap_lock(mapping); | |
353 | vma_prio_tree_remove(vma, &mapping->i_mmap); | |
354 | flush_dcache_mmap_unlock(mapping); | |
355 | } | |
356 | ||
357 | /* remove from the master list */ | |
358 | rb_erase(&vma->vm_rb, &nommu_vma_tree); | |
359 | } | |
360 | ||
361 | /* | |
362 | * determine whether a mapping should be permitted and, if so, what sort of | |
363 | * mapping we're capable of supporting | |
364 | */ | |
365 | static int validate_mmap_request(struct file *file, | |
366 | unsigned long addr, | |
367 | unsigned long len, | |
368 | unsigned long prot, | |
369 | unsigned long flags, | |
370 | unsigned long pgoff, | |
371 | unsigned long *_capabilities) | |
372 | { | |
373 | unsigned long capabilities; | |
374 | unsigned long reqprot = prot; | |
375 | int ret; | |
376 | ||
377 | /* do the simple checks first */ | |
378 | if (flags & MAP_FIXED || addr) { | |
379 | printk(KERN_DEBUG | |
380 | "%d: Can't do fixed-address/overlay mmap of RAM\n", | |
381 | current->pid); | |
382 | return -EINVAL; | |
383 | } | |
384 | ||
385 | if ((flags & MAP_TYPE) != MAP_PRIVATE && | |
386 | (flags & MAP_TYPE) != MAP_SHARED) | |
387 | return -EINVAL; | |
388 | ||
389 | if (PAGE_ALIGN(len) == 0) | |
390 | return addr; | |
391 | ||
392 | if (len > TASK_SIZE) | |
393 | return -EINVAL; | |
394 | ||
395 | /* offset overflow? */ | |
396 | if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) | |
397 | return -EINVAL; | |
398 | ||
399 | if (file) { | |
400 | /* validate file mapping requests */ | |
401 | struct address_space *mapping; | |
402 | ||
403 | /* files must support mmap */ | |
404 | if (!file->f_op || !file->f_op->mmap) | |
405 | return -ENODEV; | |
406 | ||
407 | /* work out if what we've got could possibly be shared | |
408 | * - we support chardevs that provide their own "memory" | |
409 | * - we support files/blockdevs that are memory backed | |
410 | */ | |
411 | mapping = file->f_mapping; | |
412 | if (!mapping) | |
413 | mapping = file->f_dentry->d_inode->i_mapping; | |
414 | ||
415 | capabilities = 0; | |
416 | if (mapping && mapping->backing_dev_info) | |
417 | capabilities = mapping->backing_dev_info->capabilities; | |
418 | ||
419 | if (!capabilities) { | |
420 | /* no explicit capabilities set, so assume some | |
421 | * defaults */ | |
422 | switch (file->f_dentry->d_inode->i_mode & S_IFMT) { | |
423 | case S_IFREG: | |
424 | case S_IFBLK: | |
425 | capabilities = BDI_CAP_MAP_COPY; | |
426 | break; | |
427 | ||
428 | case S_IFCHR: | |
429 | capabilities = | |
430 | BDI_CAP_MAP_DIRECT | | |
431 | BDI_CAP_READ_MAP | | |
432 | BDI_CAP_WRITE_MAP; | |
433 | break; | |
434 | ||
435 | default: | |
436 | return -EINVAL; | |
437 | } | |
438 | } | |
439 | ||
440 | /* eliminate any capabilities that we can't support on this | |
441 | * device */ | |
442 | if (!file->f_op->get_unmapped_area) | |
443 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
444 | if (!file->f_op->read) | |
445 | capabilities &= ~BDI_CAP_MAP_COPY; | |
446 | ||
447 | if (flags & MAP_SHARED) { | |
448 | /* do checks for writing, appending and locking */ | |
449 | if ((prot & PROT_WRITE) && | |
450 | !(file->f_mode & FMODE_WRITE)) | |
451 | return -EACCES; | |
452 | ||
453 | if (IS_APPEND(file->f_dentry->d_inode) && | |
454 | (file->f_mode & FMODE_WRITE)) | |
455 | return -EACCES; | |
456 | ||
457 | if (locks_verify_locked(file->f_dentry->d_inode)) | |
458 | return -EAGAIN; | |
459 | ||
460 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
461 | return -ENODEV; | |
462 | ||
463 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || | |
464 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || | |
465 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) | |
466 | ) { | |
467 | printk("MAP_SHARED not completely supported on !MMU\n"); | |
468 | return -EINVAL; | |
469 | } | |
470 | ||
471 | /* we mustn't privatise shared mappings */ | |
472 | capabilities &= ~BDI_CAP_MAP_COPY; | |
473 | } | |
474 | else { | |
475 | /* we're going to read the file into private memory we | |
476 | * allocate */ | |
477 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
478 | return -ENODEV; | |
479 | ||
480 | /* we don't permit a private writable mapping to be | |
481 | * shared with the backing device */ | |
482 | if (prot & PROT_WRITE) | |
483 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
484 | } | |
485 | ||
486 | /* handle executable mappings and implied executable | |
487 | * mappings */ | |
488 | if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) { | |
489 | if (prot & PROT_EXEC) | |
490 | return -EPERM; | |
491 | } | |
492 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { | |
493 | /* handle implication of PROT_EXEC by PROT_READ */ | |
494 | if (current->personality & READ_IMPLIES_EXEC) { | |
495 | if (capabilities & BDI_CAP_EXEC_MAP) | |
496 | prot |= PROT_EXEC; | |
497 | } | |
498 | } | |
499 | else if ((prot & PROT_READ) && | |
500 | (prot & PROT_EXEC) && | |
501 | !(capabilities & BDI_CAP_EXEC_MAP) | |
502 | ) { | |
503 | /* backing file is not executable, try to copy */ | |
504 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
505 | } | |
506 | } | |
507 | else { | |
508 | /* anonymous mappings are always memory backed and can be | |
509 | * privately mapped | |
510 | */ | |
511 | capabilities = BDI_CAP_MAP_COPY; | |
512 | ||
513 | /* handle PROT_EXEC implication by PROT_READ */ | |
514 | if ((prot & PROT_READ) && | |
515 | (current->personality & READ_IMPLIES_EXEC)) | |
516 | prot |= PROT_EXEC; | |
517 | } | |
518 | ||
519 | /* allow the security API to have its say */ | |
520 | ret = security_file_mmap(file, reqprot, prot, flags); | |
521 | if (ret < 0) | |
522 | return ret; | |
523 | ||
524 | /* looks okay */ | |
525 | *_capabilities = capabilities; | |
526 | return 0; | |
527 | } | |
528 | ||
529 | /* | |
530 | * we've determined that we can make the mapping, now translate what we | |
531 | * now know into VMA flags | |
532 | */ | |
533 | static unsigned long determine_vm_flags(struct file *file, | |
534 | unsigned long prot, | |
535 | unsigned long flags, | |
536 | unsigned long capabilities) | |
537 | { | |
538 | unsigned long vm_flags; | |
539 | ||
540 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); | |
541 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; | |
542 | /* vm_flags |= mm->def_flags; */ | |
543 | ||
544 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { | |
545 | /* attempt to share read-only copies of mapped file chunks */ | |
546 | if (file && !(prot & PROT_WRITE)) | |
547 | vm_flags |= VM_MAYSHARE; | |
548 | } | |
549 | else { | |
550 | /* overlay a shareable mapping on the backing device or inode | |
551 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and | |
552 | * romfs/cramfs */ | |
553 | if (flags & MAP_SHARED) | |
554 | vm_flags |= VM_MAYSHARE | VM_SHARED; | |
555 | else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0) | |
556 | vm_flags |= VM_MAYSHARE; | |
557 | } | |
558 | ||
559 | /* refuse to let anyone share private mappings with this process if | |
560 | * it's being traced - otherwise breakpoints set in it may interfere | |
561 | * with another untraced process | |
562 | */ | |
563 | if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED)) | |
564 | vm_flags &= ~VM_MAYSHARE; | |
565 | ||
566 | return vm_flags; | |
567 | } | |
568 | ||
569 | /* | |
570 | * set up a shared mapping on a file | |
571 | */ | |
572 | static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len) | |
573 | { | |
574 | int ret; | |
575 | ||
576 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
577 | if (ret != -ENOSYS) | |
578 | return ret; | |
579 | ||
580 | /* getting an ENOSYS error indicates that direct mmap isn't | |
581 | * possible (as opposed to tried but failed) so we'll fall | |
582 | * through to making a private copy of the data and mapping | |
583 | * that if we can */ | |
584 | return -ENODEV; | |
585 | } | |
586 | ||
587 | /* | |
588 | * set up a private mapping or an anonymous shared mapping | |
589 | */ | |
590 | static int do_mmap_private(struct vm_area_struct *vma, unsigned long len) | |
591 | { | |
592 | void *base; | |
593 | int ret; | |
594 | ||
595 | /* invoke the file's mapping function so that it can keep track of | |
596 | * shared mappings on devices or memory | |
597 | * - VM_MAYSHARE will be set if it may attempt to share | |
598 | */ | |
599 | if (vma->vm_file) { | |
600 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); | |
601 | if (ret != -ENOSYS) { | |
602 | /* shouldn't return success if we're not sharing */ | |
603 | BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE)); | |
604 | return ret; /* success or a real error */ | |
605 | } | |
606 | ||
607 | /* getting an ENOSYS error indicates that direct mmap isn't | |
608 | * possible (as opposed to tried but failed) so we'll try to | |
609 | * make a private copy of the data and map that instead */ | |
610 | } | |
611 | ||
612 | /* allocate some memory to hold the mapping | |
613 | * - note that this may not return a page-aligned address if the object | |
614 | * we're allocating is smaller than a page | |
615 | */ | |
616 | base = kmalloc(len, GFP_KERNEL); | |
617 | if (!base) | |
618 | goto enomem; | |
619 | ||
620 | vma->vm_start = (unsigned long) base; | |
621 | vma->vm_end = vma->vm_start + len; | |
622 | vma->vm_flags |= VM_MAPPED_COPY; | |
623 | ||
624 | #ifdef WARN_ON_SLACK | |
625 | if (len + WARN_ON_SLACK <= kobjsize(result)) | |
626 | printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n", | |
627 | len, current->pid, kobjsize(result) - len); | |
628 | #endif | |
629 | ||
630 | if (vma->vm_file) { | |
631 | /* read the contents of a file into the copy */ | |
632 | mm_segment_t old_fs; | |
633 | loff_t fpos; | |
634 | ||
635 | fpos = vma->vm_pgoff; | |
636 | fpos <<= PAGE_SHIFT; | |
637 | ||
638 | old_fs = get_fs(); | |
639 | set_fs(KERNEL_DS); | |
640 | ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); | |
641 | set_fs(old_fs); | |
642 | ||
643 | if (ret < 0) | |
644 | goto error_free; | |
645 | ||
646 | /* clear the last little bit */ | |
647 | if (ret < len) | |
648 | memset(base + ret, 0, len - ret); | |
649 | ||
650 | } else { | |
651 | /* if it's an anonymous mapping, then just clear it */ | |
652 | memset(base, 0, len); | |
653 | } | |
654 | ||
655 | return 0; | |
656 | ||
657 | error_free: | |
658 | kfree(base); | |
659 | vma->vm_start = 0; | |
660 | return ret; | |
661 | ||
662 | enomem: | |
663 | printk("Allocation of length %lu from process %d failed\n", | |
664 | len, current->pid); | |
665 | show_free_areas(); | |
666 | return -ENOMEM; | |
667 | } | |
668 | ||
669 | /* | |
670 | * handle mapping creation for uClinux | |
671 | */ | |
672 | unsigned long do_mmap_pgoff(struct file *file, | |
673 | unsigned long addr, | |
674 | unsigned long len, | |
675 | unsigned long prot, | |
676 | unsigned long flags, | |
677 | unsigned long pgoff) | |
678 | { | |
679 | struct vm_list_struct *vml = NULL; | |
680 | struct vm_area_struct *vma = NULL; | |
681 | struct rb_node *rb; | |
682 | unsigned long capabilities, vm_flags; | |
683 | void *result; | |
684 | int ret; | |
685 | ||
686 | /* decide whether we should attempt the mapping, and if so what sort of | |
687 | * mapping */ | |
688 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, | |
689 | &capabilities); | |
690 | if (ret < 0) | |
691 | return ret; | |
692 | ||
693 | /* we've determined that we can make the mapping, now translate what we | |
694 | * now know into VMA flags */ | |
695 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); | |
696 | ||
697 | /* we're going to need to record the mapping if it works */ | |
698 | vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL); | |
699 | if (!vml) | |
700 | goto error_getting_vml; | |
701 | memset(vml, 0, sizeof(*vml)); | |
702 | ||
703 | down_write(&nommu_vma_sem); | |
704 | ||
705 | /* if we want to share, we need to check for VMAs created by other | |
706 | * mmap() calls that overlap with our proposed mapping | |
707 | * - we can only share with an exact match on most regular files | |
708 | * - shared mappings on character devices and memory backed files are | |
709 | * permitted to overlap inexactly as far as we are concerned for in | |
710 | * these cases, sharing is handled in the driver or filesystem rather | |
711 | * than here | |
712 | */ | |
713 | if (vm_flags & VM_MAYSHARE) { | |
714 | unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
715 | unsigned long vmpglen; | |
716 | ||
717 | for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) { | |
718 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); | |
719 | ||
720 | if (!(vma->vm_flags & VM_MAYSHARE)) | |
721 | continue; | |
722 | ||
723 | /* search for overlapping mappings on the same file */ | |
724 | if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode) | |
725 | continue; | |
726 | ||
727 | if (vma->vm_pgoff >= pgoff + pglen) | |
728 | continue; | |
729 | ||
730 | vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1; | |
731 | vmpglen >>= PAGE_SHIFT; | |
732 | if (pgoff >= vma->vm_pgoff + vmpglen) | |
733 | continue; | |
734 | ||
735 | /* handle inexactly overlapping matches between mappings */ | |
736 | if (vma->vm_pgoff != pgoff || vmpglen != pglen) { | |
737 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) | |
738 | goto sharing_violation; | |
739 | continue; | |
740 | } | |
741 | ||
742 | /* we've found a VMA we can share */ | |
743 | atomic_inc(&vma->vm_usage); | |
744 | ||
745 | vml->vma = vma; | |
746 | result = (void *) vma->vm_start; | |
747 | goto shared; | |
748 | } | |
749 | ||
750 | vma = NULL; | |
751 | ||
752 | /* obtain the address at which to make a shared mapping | |
753 | * - this is the hook for quasi-memory character devices to | |
754 | * tell us the location of a shared mapping | |
755 | */ | |
756 | if (file && file->f_op->get_unmapped_area) { | |
757 | addr = file->f_op->get_unmapped_area(file, addr, len, | |
758 | pgoff, flags); | |
759 | if (IS_ERR((void *) addr)) { | |
760 | ret = addr; | |
761 | if (ret != (unsigned long) -ENOSYS) | |
762 | goto error; | |
763 | ||
764 | /* the driver refused to tell us where to site | |
765 | * the mapping so we'll have to attempt to copy | |
766 | * it */ | |
767 | ret = (unsigned long) -ENODEV; | |
768 | if (!(capabilities & BDI_CAP_MAP_COPY)) | |
769 | goto error; | |
770 | ||
771 | capabilities &= ~BDI_CAP_MAP_DIRECT; | |
772 | } | |
773 | } | |
774 | } | |
775 | ||
776 | /* we're going to need a VMA struct as well */ | |
777 | vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL); | |
778 | if (!vma) | |
779 | goto error_getting_vma; | |
780 | ||
781 | memset(vma, 0, sizeof(*vma)); | |
782 | INIT_LIST_HEAD(&vma->anon_vma_node); | |
783 | atomic_set(&vma->vm_usage, 1); | |
784 | if (file) | |
785 | get_file(file); | |
786 | vma->vm_file = file; | |
787 | vma->vm_flags = vm_flags; | |
788 | vma->vm_start = addr; | |
789 | vma->vm_end = addr + len; | |
790 | vma->vm_pgoff = pgoff; | |
791 | ||
792 | vml->vma = vma; | |
793 | ||
794 | /* set up the mapping */ | |
795 | if (file && vma->vm_flags & VM_SHARED) | |
796 | ret = do_mmap_shared_file(vma, len); | |
797 | else | |
798 | ret = do_mmap_private(vma, len); | |
799 | if (ret < 0) | |
800 | goto error; | |
801 | ||
802 | /* okay... we have a mapping; now we have to register it */ | |
803 | result = (void *) vma->vm_start; | |
804 | ||
805 | if (vma->vm_flags & VM_MAPPED_COPY) { | |
806 | realalloc += kobjsize(result); | |
807 | askedalloc += len; | |
808 | } | |
809 | ||
810 | realalloc += kobjsize(vma); | |
811 | askedalloc += sizeof(*vma); | |
812 | ||
813 | current->mm->total_vm += len >> PAGE_SHIFT; | |
814 | ||
815 | add_nommu_vma(vma); | |
816 | ||
817 | shared: | |
818 | realalloc += kobjsize(vml); | |
819 | askedalloc += sizeof(*vml); | |
820 | ||
821 | vml->next = current->mm->context.vmlist; | |
822 | current->mm->context.vmlist = vml; | |
823 | ||
824 | up_write(&nommu_vma_sem); | |
825 | ||
826 | if (prot & PROT_EXEC) | |
827 | flush_icache_range((unsigned long) result, | |
828 | (unsigned long) result + len); | |
829 | ||
830 | #ifdef DEBUG | |
831 | printk("do_mmap:\n"); | |
832 | show_process_blocks(); | |
833 | #endif | |
834 | ||
835 | return (unsigned long) result; | |
836 | ||
837 | error: | |
838 | up_write(&nommu_vma_sem); | |
839 | kfree(vml); | |
840 | if (vma) { | |
841 | fput(vma->vm_file); | |
842 | kfree(vma); | |
843 | } | |
844 | return ret; | |
845 | ||
846 | sharing_violation: | |
847 | up_write(&nommu_vma_sem); | |
848 | printk("Attempt to share mismatched mappings\n"); | |
849 | kfree(vml); | |
850 | return -EINVAL; | |
851 | ||
852 | error_getting_vma: | |
853 | up_write(&nommu_vma_sem); | |
854 | kfree(vml); | |
855 | printk("Allocation of vml for %lu byte allocation from process %d failed\n", | |
856 | len, current->pid); | |
857 | show_free_areas(); | |
858 | return -ENOMEM; | |
859 | ||
860 | error_getting_vml: | |
861 | printk("Allocation of vml for %lu byte allocation from process %d failed\n", | |
862 | len, current->pid); | |
863 | show_free_areas(); | |
864 | return -ENOMEM; | |
865 | } | |
866 | ||
867 | /* | |
868 | * handle mapping disposal for uClinux | |
869 | */ | |
870 | static void put_vma(struct vm_area_struct *vma) | |
871 | { | |
872 | if (vma) { | |
873 | down_write(&nommu_vma_sem); | |
874 | ||
875 | if (atomic_dec_and_test(&vma->vm_usage)) { | |
876 | delete_nommu_vma(vma); | |
877 | ||
878 | if (vma->vm_ops && vma->vm_ops->close) | |
879 | vma->vm_ops->close(vma); | |
880 | ||
881 | /* IO memory and memory shared directly out of the pagecache from | |
882 | * ramfs/tmpfs mustn't be released here */ | |
883 | if (vma->vm_flags & VM_MAPPED_COPY) { | |
884 | realalloc -= kobjsize((void *) vma->vm_start); | |
885 | askedalloc -= vma->vm_end - vma->vm_start; | |
886 | kfree((void *) vma->vm_start); | |
887 | } | |
888 | ||
889 | realalloc -= kobjsize(vma); | |
890 | askedalloc -= sizeof(*vma); | |
891 | ||
892 | if (vma->vm_file) | |
893 | fput(vma->vm_file); | |
894 | kfree(vma); | |
895 | } | |
896 | ||
897 | up_write(&nommu_vma_sem); | |
898 | } | |
899 | } | |
900 | ||
901 | int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) | |
902 | { | |
903 | struct vm_list_struct *vml, **parent; | |
904 | unsigned long end = addr + len; | |
905 | ||
906 | #ifdef DEBUG | |
907 | printk("do_munmap:\n"); | |
908 | #endif | |
909 | ||
910 | for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) | |
911 | if ((*parent)->vma->vm_start == addr && | |
912 | (*parent)->vma->vm_end == end) | |
913 | goto found; | |
914 | ||
915 | printk("munmap of non-mmaped memory by process %d (%s): %p\n", | |
916 | current->pid, current->comm, (void *) addr); | |
917 | return -EINVAL; | |
918 | ||
919 | found: | |
920 | vml = *parent; | |
921 | ||
922 | put_vma(vml->vma); | |
923 | ||
924 | *parent = vml->next; | |
925 | realalloc -= kobjsize(vml); | |
926 | askedalloc -= sizeof(*vml); | |
927 | kfree(vml); | |
928 | mm->total_vm -= len >> PAGE_SHIFT; | |
929 | ||
930 | #ifdef DEBUG | |
931 | show_process_blocks(); | |
932 | #endif | |
933 | ||
934 | return 0; | |
935 | } | |
936 | ||
937 | /* Release all mmaps. */ | |
938 | void exit_mmap(struct mm_struct * mm) | |
939 | { | |
940 | struct vm_list_struct *tmp; | |
941 | ||
942 | if (mm) { | |
943 | #ifdef DEBUG | |
944 | printk("Exit_mmap:\n"); | |
945 | #endif | |
946 | ||
947 | mm->total_vm = 0; | |
948 | ||
949 | while ((tmp = mm->context.vmlist)) { | |
950 | mm->context.vmlist = tmp->next; | |
951 | put_vma(tmp->vma); | |
952 | ||
953 | realalloc -= kobjsize(tmp); | |
954 | askedalloc -= sizeof(*tmp); | |
955 | kfree(tmp); | |
956 | } | |
957 | ||
958 | #ifdef DEBUG | |
959 | show_process_blocks(); | |
960 | #endif | |
961 | } | |
962 | } | |
963 | ||
964 | asmlinkage long sys_munmap(unsigned long addr, size_t len) | |
965 | { | |
966 | int ret; | |
967 | struct mm_struct *mm = current->mm; | |
968 | ||
969 | down_write(&mm->mmap_sem); | |
970 | ret = do_munmap(mm, addr, len); | |
971 | up_write(&mm->mmap_sem); | |
972 | return ret; | |
973 | } | |
974 | ||
975 | unsigned long do_brk(unsigned long addr, unsigned long len) | |
976 | { | |
977 | return -ENOMEM; | |
978 | } | |
979 | ||
980 | /* | |
981 | * Expand (or shrink) an existing mapping, potentially moving it at the | |
982 | * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
983 | * | |
984 | * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise | |
985 | * This option implies MREMAP_MAYMOVE. | |
986 | * | |
987 | * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the | |
988 | * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable | |
989 | */ | |
990 | unsigned long do_mremap(unsigned long addr, | |
991 | unsigned long old_len, unsigned long new_len, | |
992 | unsigned long flags, unsigned long new_addr) | |
993 | { | |
994 | struct vm_list_struct *vml = NULL; | |
995 | ||
996 | /* insanity checks first */ | |
997 | if (new_len == 0) | |
998 | return (unsigned long) -EINVAL; | |
999 | ||
1000 | if (flags & MREMAP_FIXED && new_addr != addr) | |
1001 | return (unsigned long) -EINVAL; | |
1002 | ||
1003 | for (vml = current->mm->context.vmlist; vml; vml = vml->next) | |
1004 | if (vml->vma->vm_start == addr) | |
1005 | goto found; | |
1006 | ||
1007 | return (unsigned long) -EINVAL; | |
1008 | ||
1009 | found: | |
1010 | if (vml->vma->vm_end != vml->vma->vm_start + old_len) | |
1011 | return (unsigned long) -EFAULT; | |
1012 | ||
1013 | if (vml->vma->vm_flags & VM_MAYSHARE) | |
1014 | return (unsigned long) -EPERM; | |
1015 | ||
1016 | if (new_len > kobjsize((void *) addr)) | |
1017 | return (unsigned long) -ENOMEM; | |
1018 | ||
1019 | /* all checks complete - do it */ | |
1020 | vml->vma->vm_end = vml->vma->vm_start + new_len; | |
1021 | ||
1022 | askedalloc -= old_len; | |
1023 | askedalloc += new_len; | |
1024 | ||
1025 | return vml->vma->vm_start; | |
1026 | } | |
1027 | ||
1028 | /* | |
1029 | * Look up the first VMA which satisfies addr < vm_end, NULL if none | |
1030 | */ | |
1031 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) | |
1032 | { | |
1033 | struct vm_list_struct *vml; | |
1034 | ||
1035 | for (vml = mm->context.vmlist; vml; vml = vml->next) | |
1036 | if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end) | |
1037 | return vml->vma; | |
1038 | ||
1039 | return NULL; | |
1040 | } | |
1041 | ||
1042 | EXPORT_SYMBOL(find_vma); | |
1043 | ||
1044 | struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write) | |
1045 | { | |
1046 | return NULL; | |
1047 | } | |
1048 | ||
1049 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) | |
1050 | { | |
1051 | return NULL; | |
1052 | } | |
1053 | ||
1054 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, | |
1055 | unsigned long to, unsigned long size, pgprot_t prot) | |
1056 | { | |
1057 | return -EPERM; | |
1058 | } | |
1059 | ||
1060 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) | |
1061 | { | |
1062 | } | |
1063 | ||
1064 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, | |
1065 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
1066 | { | |
1067 | return -ENOMEM; | |
1068 | } | |
1069 | ||
1363c3cd | 1070 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
1071 | { |
1072 | } | |
1073 | ||
1074 | void update_mem_hiwater(struct task_struct *tsk) | |
1075 | { | |
1076 | unsigned long rss = get_mm_counter(tsk->mm, rss); | |
1077 | ||
1078 | if (likely(tsk->mm)) { | |
1079 | if (tsk->mm->hiwater_rss < rss) | |
1080 | tsk->mm->hiwater_rss = rss; | |
1081 | if (tsk->mm->hiwater_vm < tsk->mm->total_vm) | |
1082 | tsk->mm->hiwater_vm = tsk->mm->total_vm; | |
1083 | } | |
1084 | } | |
1085 | ||
1086 | void unmap_mapping_range(struct address_space *mapping, | |
1087 | loff_t const holebegin, loff_t const holelen, | |
1088 | int even_cows) | |
1089 | { | |
1090 | } | |
1091 | ||
1092 | /* | |
1093 | * Check that a process has enough memory to allocate a new virtual | |
1094 | * mapping. 0 means there is enough memory for the allocation to | |
1095 | * succeed and -ENOMEM implies there is not. | |
1096 | * | |
1097 | * We currently support three overcommit policies, which are set via the | |
1098 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting | |
1099 | * | |
1100 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. | |
1101 | * Additional code 2002 Jul 20 by Robert Love. | |
1102 | * | |
1103 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. | |
1104 | * | |
1105 | * Note this is a helper function intended to be used by LSMs which | |
1106 | * wish to use this logic. | |
1107 | */ | |
1108 | int __vm_enough_memory(long pages, int cap_sys_admin) | |
1109 | { | |
1110 | unsigned long free, allowed; | |
1111 | ||
1112 | vm_acct_memory(pages); | |
1113 | ||
1114 | /* | |
1115 | * Sometimes we want to use more memory than we have | |
1116 | */ | |
1117 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) | |
1118 | return 0; | |
1119 | ||
1120 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { | |
1121 | unsigned long n; | |
1122 | ||
1123 | free = get_page_cache_size(); | |
1124 | free += nr_swap_pages; | |
1125 | ||
1126 | /* | |
1127 | * Any slabs which are created with the | |
1128 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents | |
1129 | * which are reclaimable, under pressure. The dentry | |
1130 | * cache and most inode caches should fall into this | |
1131 | */ | |
1132 | free += atomic_read(&slab_reclaim_pages); | |
1133 | ||
1134 | /* | |
1135 | * Leave the last 3% for root | |
1136 | */ | |
1137 | if (!cap_sys_admin) | |
1138 | free -= free / 32; | |
1139 | ||
1140 | if (free > pages) | |
1141 | return 0; | |
1142 | ||
1143 | /* | |
1144 | * nr_free_pages() is very expensive on large systems, | |
1145 | * only call if we're about to fail. | |
1146 | */ | |
1147 | n = nr_free_pages(); | |
1148 | if (!cap_sys_admin) | |
1149 | n -= n / 32; | |
1150 | free += n; | |
1151 | ||
1152 | if (free > pages) | |
1153 | return 0; | |
1154 | vm_unacct_memory(pages); | |
1155 | return -ENOMEM; | |
1156 | } | |
1157 | ||
1158 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; | |
1159 | /* | |
1160 | * Leave the last 3% for root | |
1161 | */ | |
1162 | if (!cap_sys_admin) | |
1163 | allowed -= allowed / 32; | |
1164 | allowed += total_swap_pages; | |
1165 | ||
1166 | /* Don't let a single process grow too big: | |
1167 | leave 3% of the size of this process for other processes */ | |
1168 | allowed -= current->mm->total_vm / 32; | |
1169 | ||
2f60f8d3 SD |
1170 | /* |
1171 | * cast `allowed' as a signed long because vm_committed_space | |
1172 | * sometimes has a negative value | |
1173 | */ | |
1174 | if (atomic_read(&vm_committed_space) < (long)allowed) | |
1da177e4 LT |
1175 | return 0; |
1176 | ||
1177 | vm_unacct_memory(pages); | |
1178 | ||
1179 | return -ENOMEM; | |
1180 | } | |
1181 | ||
1182 | int in_gate_area_no_task(unsigned long addr) | |
1183 | { | |
1184 | return 0; | |
1185 | } |