blob: ce74452c02d945e40e6cdb503499609f24e1cd64 [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
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 */
68int 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
80do_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
88out_truncate:
89 if (inode->i_op && inode->i_op->truncate)
90 inode->i_op->truncate(inode);
91 return 0;
92out_sig:
93 send_sig(SIGXFSZ, current, 0);
94out:
95 return -EFBIG;
96}
97
98EXPORT_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 */
106unsigned 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 */
125int 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
145DEFINE_RWLOCK(vmlist_lock);
146struct vm_struct *vmlist;
147
148void vfree(void *addr)
149{
150 kfree(addr);
151}
152
Adrian Bunk7a019222005-05-16 21:53:37 -0700153void *__vmalloc(unsigned long size, unsigned int __nocast gfp_mask,
154 pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
156 /*
157 * kmalloc doesn't like __GFP_HIGHMEM for some reason
158 */
159 return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
160}
161
162struct page * vmalloc_to_page(void *addr)
163{
164 return virt_to_page(addr);
165}
166
167unsigned long vmalloc_to_pfn(void *addr)
168{
169 return page_to_pfn(virt_to_page(addr));
170}
171
172
173long vread(char *buf, char *addr, unsigned long count)
174{
175 memcpy(buf, addr, count);
176 return count;
177}
178
179long 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 */
200void *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 */
213void *vmalloc_32(unsigned long size)
214{
215 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
216}
217
218void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
219{
220 BUG();
221 return NULL;
222}
223
224void 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 */
236asmlinkage 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
261static void show_process_blocks(void)
262{
263 struct vm_list_struct *vml;
264
265 printk("Process blocks %d:", current->pid);
266
267 for (vml = &current->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
279static 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
298static 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
344static 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 */
365static 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 */
533static 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 */
572static 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 */
590static 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
657error_free:
658 kfree(base);
659 vma->vm_start = 0;
660 return ret;
661
662enomem:
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 */
672unsigned 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 */
870static 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
901int 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. */
938void 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
964asmlinkage 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
975unsigned 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 */
990unsigned 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 */
1031struct 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
1042EXPORT_SYMBOL(find_vma);
1043
1044struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write)
1045{
1046 return NULL;
1047}
1048
1049struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1050{
1051 return NULL;
1052}
1053
1054int 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
1060void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1061{
1062}
1063
1064unsigned 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
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001070void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071{
1072}
1073
1074void 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
1086void 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 */
1108int __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
1178int in_gate_area_no_task(unsigned long addr)
1179{
1180 return 0;
1181}