blob: d1e076a487cbe3eff161ca2f2472186977f30e41 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
35void *high_memory;
36struct page *mem_map;
37unsigned long max_mapnr;
38unsigned long num_physpages;
39unsigned long askedalloc, realalloc;
40atomic_t vm_committed_space = ATOMIC_INIT(0);
41int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
42int sysctl_overcommit_ratio = 50; /* default is 50% */
43int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
44int heap_stack_gap = 0;
45
46EXPORT_SYMBOL(mem_map);
47EXPORT_SYMBOL(sysctl_max_map_count);
48EXPORT_SYMBOL(sysctl_overcommit_memory);
49EXPORT_SYMBOL(sysctl_overcommit_ratio);
50EXPORT_SYMBOL(vm_committed_space);
51EXPORT_SYMBOL(__vm_enough_memory);
52
53/* list of shareable VMAs */
54struct rb_root nommu_vma_tree = RB_ROOT;
55DECLARE_RWSEM(nommu_vma_sem);
56
57struct vm_operations_struct generic_file_vm_ops = {
58};
59
Greg Ungerer66aa2b42005-09-12 11:18:10 +100060EXPORT_SYMBOL(vmalloc);
61EXPORT_SYMBOL(vfree);
62EXPORT_SYMBOL(vmalloc_to_page);
63EXPORT_SYMBOL(vmalloc_32);
64
Linus Torvalds1da177e2005-04-16 15:20:36 -070065/*
66 * Handle all mappings that got truncated by a "truncate()"
67 * system call.
68 *
69 * NOTE! We have to be ready to update the memory sharing
70 * between the file and the memory map for a potential last
71 * incomplete page. Ugly, but necessary.
72 */
73int vmtruncate(struct inode *inode, loff_t offset)
74{
75 struct address_space *mapping = inode->i_mapping;
76 unsigned long limit;
77
78 if (inode->i_size < offset)
79 goto do_expand;
80 i_size_write(inode, offset);
81
82 truncate_inode_pages(mapping, offset);
83 goto out_truncate;
84
85do_expand:
86 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
87 if (limit != RLIM_INFINITY && offset > limit)
88 goto out_sig;
89 if (offset > inode->i_sb->s_maxbytes)
90 goto out;
91 i_size_write(inode, offset);
92
93out_truncate:
94 if (inode->i_op && inode->i_op->truncate)
95 inode->i_op->truncate(inode);
96 return 0;
97out_sig:
98 send_sig(SIGXFSZ, current, 0);
99out:
100 return -EFBIG;
101}
102
103EXPORT_SYMBOL(vmtruncate);
104
105/*
106 * Return the total memory allocated for this pointer, not
107 * just what the caller asked for.
108 *
109 * Doesn't have to be accurate, i.e. may have races.
110 */
111unsigned int kobjsize(const void *objp)
112{
113 struct page *page;
114
115 if (!objp || !((page = virt_to_page(objp))))
116 return 0;
117
118 if (PageSlab(page))
119 return ksize(objp);
120
121 BUG_ON(page->index < 0);
122 BUG_ON(page->index >= MAX_ORDER);
123
124 return (PAGE_SIZE << page->index);
125}
126
127/*
128 * The nommu dodgy version :-)
129 */
130int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
131 unsigned long start, int len, int write, int force,
132 struct page **pages, struct vm_area_struct **vmas)
133{
134 int i;
135 static struct vm_area_struct dummy_vma;
136
137 for (i = 0; i < len; i++) {
138 if (pages) {
139 pages[i] = virt_to_page(start);
140 if (pages[i])
141 page_cache_get(pages[i]);
142 }
143 if (vmas)
144 vmas[i] = &dummy_vma;
145 start += PAGE_SIZE;
146 }
147 return(i);
148}
149
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000150EXPORT_SYMBOL(get_user_pages);
151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152DEFINE_RWLOCK(vmlist_lock);
153struct vm_struct *vmlist;
154
155void vfree(void *addr)
156{
157 kfree(addr);
158}
159
Al Virodd0fc662005-10-07 07:46:04 +0100160void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
162 /*
163 * kmalloc doesn't like __GFP_HIGHMEM for some reason
164 */
165 return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
166}
167
168struct page * vmalloc_to_page(void *addr)
169{
170 return virt_to_page(addr);
171}
172
173unsigned long vmalloc_to_pfn(void *addr)
174{
175 return page_to_pfn(virt_to_page(addr));
176}
177
178
179long vread(char *buf, char *addr, unsigned long count)
180{
181 memcpy(buf, addr, count);
182 return count;
183}
184
185long vwrite(char *buf, char *addr, unsigned long count)
186{
187 /* Don't allow overflow */
188 if ((unsigned long) addr + count < count)
189 count = -(unsigned long) addr;
190
191 memcpy(addr, buf, count);
192 return(count);
193}
194
195/*
196 * vmalloc - allocate virtually continguos memory
197 *
198 * @size: allocation size
199 *
200 * Allocate enough pages to cover @size from the page level
201 * allocator and map them into continguos kernel virtual space.
202 *
203 * For tight cotrol over page level allocator and protection flags
204 * use __vmalloc() instead.
205 */
206void *vmalloc(unsigned long size)
207{
208 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
209}
210
211/*
212 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
213 *
214 * @size: allocation size
215 *
216 * Allocate enough 32bit PA addressable pages to cover @size from the
217 * page level allocator and map them into continguos kernel virtual space.
218 */
219void *vmalloc_32(unsigned long size)
220{
221 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
222}
223
224void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
225{
226 BUG();
227 return NULL;
228}
229
230void vunmap(void *addr)
231{
232 BUG();
233}
234
235/*
236 * sys_brk() for the most part doesn't need the global kernel
237 * lock, except when an application is doing something nasty
238 * like trying to un-brk an area that has already been mapped
239 * to a regular file. in this case, the unmapping will need
240 * to invoke file system routines that need the global lock.
241 */
242asmlinkage unsigned long sys_brk(unsigned long brk)
243{
244 struct mm_struct *mm = current->mm;
245
246 if (brk < mm->start_brk || brk > mm->context.end_brk)
247 return mm->brk;
248
249 if (mm->brk == brk)
250 return mm->brk;
251
252 /*
253 * Always allow shrinking brk
254 */
255 if (brk <= mm->brk) {
256 mm->brk = brk;
257 return brk;
258 }
259
260 /*
261 * Ok, looks good - let it rip.
262 */
263 return mm->brk = brk;
264}
265
266#ifdef DEBUG
267static void show_process_blocks(void)
268{
269 struct vm_list_struct *vml;
270
271 printk("Process blocks %d:", current->pid);
272
273 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
274 printk(" %p: %p", vml, vml->vma);
275 if (vml->vma)
276 printk(" (%d @%lx #%d)",
277 kobjsize((void *) vml->vma->vm_start),
278 vml->vma->vm_start,
279 atomic_read(&vml->vma->vm_usage));
280 printk(vml->next ? " ->" : ".\n");
281 }
282}
283#endif /* DEBUG */
284
285static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
286{
287 struct vm_area_struct *vma;
288 struct rb_node *n = nommu_vma_tree.rb_node;
289
290 while (n) {
291 vma = rb_entry(n, struct vm_area_struct, vm_rb);
292
293 if (start < vma->vm_start)
294 n = n->rb_left;
295 else if (start > vma->vm_start)
296 n = n->rb_right;
297 else
298 return vma;
299 }
300
301 return NULL;
302}
303
304static void add_nommu_vma(struct vm_area_struct *vma)
305{
306 struct vm_area_struct *pvma;
307 struct address_space *mapping;
308 struct rb_node **p = &nommu_vma_tree.rb_node;
309 struct rb_node *parent = NULL;
310
311 /* add the VMA to the mapping */
312 if (vma->vm_file) {
313 mapping = vma->vm_file->f_mapping;
314
315 flush_dcache_mmap_lock(mapping);
316 vma_prio_tree_insert(vma, &mapping->i_mmap);
317 flush_dcache_mmap_unlock(mapping);
318 }
319
320 /* add the VMA to the master list */
321 while (*p) {
322 parent = *p;
323 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
324
325 if (vma->vm_start < pvma->vm_start) {
326 p = &(*p)->rb_left;
327 }
328 else if (vma->vm_start > pvma->vm_start) {
329 p = &(*p)->rb_right;
330 }
331 else {
332 /* mappings are at the same address - this can only
333 * happen for shared-mem chardevs and shared file
334 * mappings backed by ramfs/tmpfs */
335 BUG_ON(!(pvma->vm_flags & VM_SHARED));
336
337 if (vma < pvma)
338 p = &(*p)->rb_left;
339 else if (vma > pvma)
340 p = &(*p)->rb_right;
341 else
342 BUG();
343 }
344 }
345
346 rb_link_node(&vma->vm_rb, parent, p);
347 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
348}
349
350static void delete_nommu_vma(struct vm_area_struct *vma)
351{
352 struct address_space *mapping;
353
354 /* remove the VMA from the mapping */
355 if (vma->vm_file) {
356 mapping = vma->vm_file->f_mapping;
357
358 flush_dcache_mmap_lock(mapping);
359 vma_prio_tree_remove(vma, &mapping->i_mmap);
360 flush_dcache_mmap_unlock(mapping);
361 }
362
363 /* remove from the master list */
364 rb_erase(&vma->vm_rb, &nommu_vma_tree);
365}
366
367/*
368 * determine whether a mapping should be permitted and, if so, what sort of
369 * mapping we're capable of supporting
370 */
371static int validate_mmap_request(struct file *file,
372 unsigned long addr,
373 unsigned long len,
374 unsigned long prot,
375 unsigned long flags,
376 unsigned long pgoff,
377 unsigned long *_capabilities)
378{
379 unsigned long capabilities;
380 unsigned long reqprot = prot;
381 int ret;
382
383 /* do the simple checks first */
384 if (flags & MAP_FIXED || addr) {
385 printk(KERN_DEBUG
386 "%d: Can't do fixed-address/overlay mmap of RAM\n",
387 current->pid);
388 return -EINVAL;
389 }
390
391 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
392 (flags & MAP_TYPE) != MAP_SHARED)
393 return -EINVAL;
394
395 if (PAGE_ALIGN(len) == 0)
396 return addr;
397
398 if (len > TASK_SIZE)
399 return -EINVAL;
400
401 /* offset overflow? */
402 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
403 return -EINVAL;
404
405 if (file) {
406 /* validate file mapping requests */
407 struct address_space *mapping;
408
409 /* files must support mmap */
410 if (!file->f_op || !file->f_op->mmap)
411 return -ENODEV;
412
413 /* work out if what we've got could possibly be shared
414 * - we support chardevs that provide their own "memory"
415 * - we support files/blockdevs that are memory backed
416 */
417 mapping = file->f_mapping;
418 if (!mapping)
419 mapping = file->f_dentry->d_inode->i_mapping;
420
421 capabilities = 0;
422 if (mapping && mapping->backing_dev_info)
423 capabilities = mapping->backing_dev_info->capabilities;
424
425 if (!capabilities) {
426 /* no explicit capabilities set, so assume some
427 * defaults */
428 switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
429 case S_IFREG:
430 case S_IFBLK:
431 capabilities = BDI_CAP_MAP_COPY;
432 break;
433
434 case S_IFCHR:
435 capabilities =
436 BDI_CAP_MAP_DIRECT |
437 BDI_CAP_READ_MAP |
438 BDI_CAP_WRITE_MAP;
439 break;
440
441 default:
442 return -EINVAL;
443 }
444 }
445
446 /* eliminate any capabilities that we can't support on this
447 * device */
448 if (!file->f_op->get_unmapped_area)
449 capabilities &= ~BDI_CAP_MAP_DIRECT;
450 if (!file->f_op->read)
451 capabilities &= ~BDI_CAP_MAP_COPY;
452
453 if (flags & MAP_SHARED) {
454 /* do checks for writing, appending and locking */
455 if ((prot & PROT_WRITE) &&
456 !(file->f_mode & FMODE_WRITE))
457 return -EACCES;
458
459 if (IS_APPEND(file->f_dentry->d_inode) &&
460 (file->f_mode & FMODE_WRITE))
461 return -EACCES;
462
463 if (locks_verify_locked(file->f_dentry->d_inode))
464 return -EAGAIN;
465
466 if (!(capabilities & BDI_CAP_MAP_DIRECT))
467 return -ENODEV;
468
469 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
470 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
471 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
472 ) {
473 printk("MAP_SHARED not completely supported on !MMU\n");
474 return -EINVAL;
475 }
476
477 /* we mustn't privatise shared mappings */
478 capabilities &= ~BDI_CAP_MAP_COPY;
479 }
480 else {
481 /* we're going to read the file into private memory we
482 * allocate */
483 if (!(capabilities & BDI_CAP_MAP_COPY))
484 return -ENODEV;
485
486 /* we don't permit a private writable mapping to be
487 * shared with the backing device */
488 if (prot & PROT_WRITE)
489 capabilities &= ~BDI_CAP_MAP_DIRECT;
490 }
491
492 /* handle executable mappings and implied executable
493 * mappings */
494 if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
495 if (prot & PROT_EXEC)
496 return -EPERM;
497 }
498 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
499 /* handle implication of PROT_EXEC by PROT_READ */
500 if (current->personality & READ_IMPLIES_EXEC) {
501 if (capabilities & BDI_CAP_EXEC_MAP)
502 prot |= PROT_EXEC;
503 }
504 }
505 else if ((prot & PROT_READ) &&
506 (prot & PROT_EXEC) &&
507 !(capabilities & BDI_CAP_EXEC_MAP)
508 ) {
509 /* backing file is not executable, try to copy */
510 capabilities &= ~BDI_CAP_MAP_DIRECT;
511 }
512 }
513 else {
514 /* anonymous mappings are always memory backed and can be
515 * privately mapped
516 */
517 capabilities = BDI_CAP_MAP_COPY;
518
519 /* handle PROT_EXEC implication by PROT_READ */
520 if ((prot & PROT_READ) &&
521 (current->personality & READ_IMPLIES_EXEC))
522 prot |= PROT_EXEC;
523 }
524
525 /* allow the security API to have its say */
526 ret = security_file_mmap(file, reqprot, prot, flags);
527 if (ret < 0)
528 return ret;
529
530 /* looks okay */
531 *_capabilities = capabilities;
532 return 0;
533}
534
535/*
536 * we've determined that we can make the mapping, now translate what we
537 * now know into VMA flags
538 */
539static unsigned long determine_vm_flags(struct file *file,
540 unsigned long prot,
541 unsigned long flags,
542 unsigned long capabilities)
543{
544 unsigned long vm_flags;
545
546 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
547 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
548 /* vm_flags |= mm->def_flags; */
549
550 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
551 /* attempt to share read-only copies of mapped file chunks */
552 if (file && !(prot & PROT_WRITE))
553 vm_flags |= VM_MAYSHARE;
554 }
555 else {
556 /* overlay a shareable mapping on the backing device or inode
557 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
558 * romfs/cramfs */
559 if (flags & MAP_SHARED)
560 vm_flags |= VM_MAYSHARE | VM_SHARED;
561 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
562 vm_flags |= VM_MAYSHARE;
563 }
564
565 /* refuse to let anyone share private mappings with this process if
566 * it's being traced - otherwise breakpoints set in it may interfere
567 * with another untraced process
568 */
569 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
570 vm_flags &= ~VM_MAYSHARE;
571
572 return vm_flags;
573}
574
575/*
576 * set up a shared mapping on a file
577 */
578static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
579{
580 int ret;
581
582 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
583 if (ret != -ENOSYS)
584 return ret;
585
586 /* getting an ENOSYS error indicates that direct mmap isn't
587 * possible (as opposed to tried but failed) so we'll fall
588 * through to making a private copy of the data and mapping
589 * that if we can */
590 return -ENODEV;
591}
592
593/*
594 * set up a private mapping or an anonymous shared mapping
595 */
596static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
597{
598 void *base;
599 int ret;
600
601 /* invoke the file's mapping function so that it can keep track of
602 * shared mappings on devices or memory
603 * - VM_MAYSHARE will be set if it may attempt to share
604 */
605 if (vma->vm_file) {
606 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
607 if (ret != -ENOSYS) {
608 /* shouldn't return success if we're not sharing */
609 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
610 return ret; /* success or a real error */
611 }
612
613 /* getting an ENOSYS error indicates that direct mmap isn't
614 * possible (as opposed to tried but failed) so we'll try to
615 * make a private copy of the data and map that instead */
616 }
617
618 /* allocate some memory to hold the mapping
619 * - note that this may not return a page-aligned address if the object
620 * we're allocating is smaller than a page
621 */
622 base = kmalloc(len, GFP_KERNEL);
623 if (!base)
624 goto enomem;
625
626 vma->vm_start = (unsigned long) base;
627 vma->vm_end = vma->vm_start + len;
628 vma->vm_flags |= VM_MAPPED_COPY;
629
630#ifdef WARN_ON_SLACK
631 if (len + WARN_ON_SLACK <= kobjsize(result))
632 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
633 len, current->pid, kobjsize(result) - len);
634#endif
635
636 if (vma->vm_file) {
637 /* read the contents of a file into the copy */
638 mm_segment_t old_fs;
639 loff_t fpos;
640
641 fpos = vma->vm_pgoff;
642 fpos <<= PAGE_SHIFT;
643
644 old_fs = get_fs();
645 set_fs(KERNEL_DS);
646 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
647 set_fs(old_fs);
648
649 if (ret < 0)
650 goto error_free;
651
652 /* clear the last little bit */
653 if (ret < len)
654 memset(base + ret, 0, len - ret);
655
656 } else {
657 /* if it's an anonymous mapping, then just clear it */
658 memset(base, 0, len);
659 }
660
661 return 0;
662
663error_free:
664 kfree(base);
665 vma->vm_start = 0;
666 return ret;
667
668enomem:
669 printk("Allocation of length %lu from process %d failed\n",
670 len, current->pid);
671 show_free_areas();
672 return -ENOMEM;
673}
674
675/*
676 * handle mapping creation for uClinux
677 */
678unsigned long do_mmap_pgoff(struct file *file,
679 unsigned long addr,
680 unsigned long len,
681 unsigned long prot,
682 unsigned long flags,
683 unsigned long pgoff)
684{
685 struct vm_list_struct *vml = NULL;
686 struct vm_area_struct *vma = NULL;
687 struct rb_node *rb;
688 unsigned long capabilities, vm_flags;
689 void *result;
690 int ret;
691
692 /* decide whether we should attempt the mapping, and if so what sort of
693 * mapping */
694 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
695 &capabilities);
696 if (ret < 0)
697 return ret;
698
699 /* we've determined that we can make the mapping, now translate what we
700 * now know into VMA flags */
701 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
702
703 /* we're going to need to record the mapping if it works */
704 vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
705 if (!vml)
706 goto error_getting_vml;
707 memset(vml, 0, sizeof(*vml));
708
709 down_write(&nommu_vma_sem);
710
711 /* if we want to share, we need to check for VMAs created by other
712 * mmap() calls that overlap with our proposed mapping
713 * - we can only share with an exact match on most regular files
714 * - shared mappings on character devices and memory backed files are
715 * permitted to overlap inexactly as far as we are concerned for in
716 * these cases, sharing is handled in the driver or filesystem rather
717 * than here
718 */
719 if (vm_flags & VM_MAYSHARE) {
720 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
721 unsigned long vmpglen;
722
723 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
724 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
725
726 if (!(vma->vm_flags & VM_MAYSHARE))
727 continue;
728
729 /* search for overlapping mappings on the same file */
730 if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
731 continue;
732
733 if (vma->vm_pgoff >= pgoff + pglen)
734 continue;
735
736 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
737 vmpglen >>= PAGE_SHIFT;
738 if (pgoff >= vma->vm_pgoff + vmpglen)
739 continue;
740
741 /* handle inexactly overlapping matches between mappings */
742 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
743 if (!(capabilities & BDI_CAP_MAP_DIRECT))
744 goto sharing_violation;
745 continue;
746 }
747
748 /* we've found a VMA we can share */
749 atomic_inc(&vma->vm_usage);
750
751 vml->vma = vma;
752 result = (void *) vma->vm_start;
753 goto shared;
754 }
755
756 vma = NULL;
757
758 /* obtain the address at which to make a shared mapping
759 * - this is the hook for quasi-memory character devices to
760 * tell us the location of a shared mapping
761 */
762 if (file && file->f_op->get_unmapped_area) {
763 addr = file->f_op->get_unmapped_area(file, addr, len,
764 pgoff, flags);
765 if (IS_ERR((void *) addr)) {
766 ret = addr;
767 if (ret != (unsigned long) -ENOSYS)
768 goto error;
769
770 /* the driver refused to tell us where to site
771 * the mapping so we'll have to attempt to copy
772 * it */
773 ret = (unsigned long) -ENODEV;
774 if (!(capabilities & BDI_CAP_MAP_COPY))
775 goto error;
776
777 capabilities &= ~BDI_CAP_MAP_DIRECT;
778 }
779 }
780 }
781
782 /* we're going to need a VMA struct as well */
783 vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
784 if (!vma)
785 goto error_getting_vma;
786
787 memset(vma, 0, sizeof(*vma));
788 INIT_LIST_HEAD(&vma->anon_vma_node);
789 atomic_set(&vma->vm_usage, 1);
790 if (file)
791 get_file(file);
792 vma->vm_file = file;
793 vma->vm_flags = vm_flags;
794 vma->vm_start = addr;
795 vma->vm_end = addr + len;
796 vma->vm_pgoff = pgoff;
797
798 vml->vma = vma;
799
800 /* set up the mapping */
801 if (file && vma->vm_flags & VM_SHARED)
802 ret = do_mmap_shared_file(vma, len);
803 else
804 ret = do_mmap_private(vma, len);
805 if (ret < 0)
806 goto error;
807
808 /* okay... we have a mapping; now we have to register it */
809 result = (void *) vma->vm_start;
810
811 if (vma->vm_flags & VM_MAPPED_COPY) {
812 realalloc += kobjsize(result);
813 askedalloc += len;
814 }
815
816 realalloc += kobjsize(vma);
817 askedalloc += sizeof(*vma);
818
819 current->mm->total_vm += len >> PAGE_SHIFT;
820
821 add_nommu_vma(vma);
822
823 shared:
824 realalloc += kobjsize(vml);
825 askedalloc += sizeof(*vml);
826
827 vml->next = current->mm->context.vmlist;
828 current->mm->context.vmlist = vml;
829
830 up_write(&nommu_vma_sem);
831
832 if (prot & PROT_EXEC)
833 flush_icache_range((unsigned long) result,
834 (unsigned long) result + len);
835
836#ifdef DEBUG
837 printk("do_mmap:\n");
838 show_process_blocks();
839#endif
840
841 return (unsigned long) result;
842
843 error:
844 up_write(&nommu_vma_sem);
845 kfree(vml);
846 if (vma) {
847 fput(vma->vm_file);
848 kfree(vma);
849 }
850 return ret;
851
852 sharing_violation:
853 up_write(&nommu_vma_sem);
854 printk("Attempt to share mismatched mappings\n");
855 kfree(vml);
856 return -EINVAL;
857
858 error_getting_vma:
859 up_write(&nommu_vma_sem);
860 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000861 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 len, current->pid);
863 show_free_areas();
864 return -ENOMEM;
865
866 error_getting_vml:
867 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
868 len, current->pid);
869 show_free_areas();
870 return -ENOMEM;
871}
872
873/*
874 * handle mapping disposal for uClinux
875 */
876static void put_vma(struct vm_area_struct *vma)
877{
878 if (vma) {
879 down_write(&nommu_vma_sem);
880
881 if (atomic_dec_and_test(&vma->vm_usage)) {
882 delete_nommu_vma(vma);
883
884 if (vma->vm_ops && vma->vm_ops->close)
885 vma->vm_ops->close(vma);
886
887 /* IO memory and memory shared directly out of the pagecache from
888 * ramfs/tmpfs mustn't be released here */
889 if (vma->vm_flags & VM_MAPPED_COPY) {
890 realalloc -= kobjsize((void *) vma->vm_start);
891 askedalloc -= vma->vm_end - vma->vm_start;
892 kfree((void *) vma->vm_start);
893 }
894
895 realalloc -= kobjsize(vma);
896 askedalloc -= sizeof(*vma);
897
898 if (vma->vm_file)
899 fput(vma->vm_file);
900 kfree(vma);
901 }
902
903 up_write(&nommu_vma_sem);
904 }
905}
906
907int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
908{
909 struct vm_list_struct *vml, **parent;
910 unsigned long end = addr + len;
911
912#ifdef DEBUG
913 printk("do_munmap:\n");
914#endif
915
916 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
917 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000918 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 goto found;
920
921 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
922 current->pid, current->comm, (void *) addr);
923 return -EINVAL;
924
925 found:
926 vml = *parent;
927
928 put_vma(vml->vma);
929
930 *parent = vml->next;
931 realalloc -= kobjsize(vml);
932 askedalloc -= sizeof(*vml);
933 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700934
935 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936 mm->total_vm -= len >> PAGE_SHIFT;
937
938#ifdef DEBUG
939 show_process_blocks();
940#endif
941
942 return 0;
943}
944
945/* Release all mmaps. */
946void exit_mmap(struct mm_struct * mm)
947{
948 struct vm_list_struct *tmp;
949
950 if (mm) {
951#ifdef DEBUG
952 printk("Exit_mmap:\n");
953#endif
954
955 mm->total_vm = 0;
956
957 while ((tmp = mm->context.vmlist)) {
958 mm->context.vmlist = tmp->next;
959 put_vma(tmp->vma);
960
961 realalloc -= kobjsize(tmp);
962 askedalloc -= sizeof(*tmp);
963 kfree(tmp);
964 }
965
966#ifdef DEBUG
967 show_process_blocks();
968#endif
969 }
970}
971
972asmlinkage long sys_munmap(unsigned long addr, size_t len)
973{
974 int ret;
975 struct mm_struct *mm = current->mm;
976
977 down_write(&mm->mmap_sem);
978 ret = do_munmap(mm, addr, len);
979 up_write(&mm->mmap_sem);
980 return ret;
981}
982
983unsigned long do_brk(unsigned long addr, unsigned long len)
984{
985 return -ENOMEM;
986}
987
988/*
989 * Expand (or shrink) an existing mapping, potentially moving it at the
990 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
991 *
992 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
993 * This option implies MREMAP_MAYMOVE.
994 *
995 * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
996 * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
997 */
998unsigned long do_mremap(unsigned long addr,
999 unsigned long old_len, unsigned long new_len,
1000 unsigned long flags, unsigned long new_addr)
1001{
1002 struct vm_list_struct *vml = NULL;
1003
1004 /* insanity checks first */
1005 if (new_len == 0)
1006 return (unsigned long) -EINVAL;
1007
1008 if (flags & MREMAP_FIXED && new_addr != addr)
1009 return (unsigned long) -EINVAL;
1010
1011 for (vml = current->mm->context.vmlist; vml; vml = vml->next)
1012 if (vml->vma->vm_start == addr)
1013 goto found;
1014
1015 return (unsigned long) -EINVAL;
1016
1017 found:
1018 if (vml->vma->vm_end != vml->vma->vm_start + old_len)
1019 return (unsigned long) -EFAULT;
1020
1021 if (vml->vma->vm_flags & VM_MAYSHARE)
1022 return (unsigned long) -EPERM;
1023
1024 if (new_len > kobjsize((void *) addr))
1025 return (unsigned long) -ENOMEM;
1026
1027 /* all checks complete - do it */
1028 vml->vma->vm_end = vml->vma->vm_start + new_len;
1029
1030 askedalloc -= old_len;
1031 askedalloc += new_len;
1032
1033 return vml->vma->vm_start;
1034}
1035
1036/*
1037 * Look up the first VMA which satisfies addr < vm_end, NULL if none
1038 */
1039struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1040{
1041 struct vm_list_struct *vml;
1042
1043 for (vml = mm->context.vmlist; vml; vml = vml->next)
1044 if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
1045 return vml->vma;
1046
1047 return NULL;
1048}
1049
1050EXPORT_SYMBOL(find_vma);
1051
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001052struct page *follow_page(struct mm_struct *mm, unsigned long address,
1053 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054{
1055 return NULL;
1056}
1057
1058struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1059{
1060 return NULL;
1061}
1062
1063int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1064 unsigned long to, unsigned long size, pgprot_t prot)
1065{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001066 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1067 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068}
1069
1070void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1071{
1072}
1073
1074unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1075 unsigned long len, unsigned long pgoff, unsigned long flags)
1076{
1077 return -ENOMEM;
1078}
1079
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001080void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081{
1082}
1083
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084void unmap_mapping_range(struct address_space *mapping,
1085 loff_t const holebegin, loff_t const holelen,
1086 int even_cows)
1087{
1088}
1089
1090/*
1091 * Check that a process has enough memory to allocate a new virtual
1092 * mapping. 0 means there is enough memory for the allocation to
1093 * succeed and -ENOMEM implies there is not.
1094 *
1095 * We currently support three overcommit policies, which are set via the
1096 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1097 *
1098 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1099 * Additional code 2002 Jul 20 by Robert Love.
1100 *
1101 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1102 *
1103 * Note this is a helper function intended to be used by LSMs which
1104 * wish to use this logic.
1105 */
1106int __vm_enough_memory(long pages, int cap_sys_admin)
1107{
1108 unsigned long free, allowed;
1109
1110 vm_acct_memory(pages);
1111
1112 /*
1113 * Sometimes we want to use more memory than we have
1114 */
1115 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1116 return 0;
1117
1118 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1119 unsigned long n;
1120
1121 free = get_page_cache_size();
1122 free += nr_swap_pages;
1123
1124 /*
1125 * Any slabs which are created with the
1126 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1127 * which are reclaimable, under pressure. The dentry
1128 * cache and most inode caches should fall into this
1129 */
1130 free += atomic_read(&slab_reclaim_pages);
1131
1132 /*
1133 * Leave the last 3% for root
1134 */
1135 if (!cap_sys_admin)
1136 free -= free / 32;
1137
1138 if (free > pages)
1139 return 0;
1140
1141 /*
1142 * nr_free_pages() is very expensive on large systems,
1143 * only call if we're about to fail.
1144 */
1145 n = nr_free_pages();
1146 if (!cap_sys_admin)
1147 n -= n / 32;
1148 free += n;
1149
1150 if (free > pages)
1151 return 0;
1152 vm_unacct_memory(pages);
1153 return -ENOMEM;
1154 }
1155
1156 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1157 /*
1158 * Leave the last 3% for root
1159 */
1160 if (!cap_sys_admin)
1161 allowed -= allowed / 32;
1162 allowed += total_swap_pages;
1163
1164 /* Don't let a single process grow too big:
1165 leave 3% of the size of this process for other processes */
1166 allowed -= current->mm->total_vm / 32;
1167
Simon Derr2f60f8d2005-08-04 19:52:03 -07001168 /*
1169 * cast `allowed' as a signed long because vm_committed_space
1170 * sometimes has a negative value
1171 */
1172 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 return 0;
1174
1175 vm_unacct_memory(pages);
1176
1177 return -ENOMEM;
1178}
1179
1180int in_gate_area_no_task(unsigned long addr)
1181{
1182 return 0;
1183}