Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/mm/nommu.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 28241 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | |
153 | void *__vmalloc(unsigned long size, unsigned int __nocast gfp_mask, |
154 | pgprot_t prot) |
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 | |
1070 | void arch_unmap_area(struct vm_area_struct *area) |
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 | |
1170 | if (atomic_read(&vm_committed_space) < allowed) |
1171 | return 0; |
1172 | |
1173 | vm_unacct_memory(pages); |
1174 | |
1175 | return -ENOMEM; |
1176 | } |
1177 | |
1178 | int in_gate_area_no_task(unsigned long addr) |
1179 | { |
1180 | return 0; |
1181 | } |