blob: 2e140a6ae22e2f20522df9291f290d89c3c13250 [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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047EXPORT_SYMBOL(__vm_enough_memory);
48
49/* list of shareable VMAs */
50struct rb_root nommu_vma_tree = RB_ROOT;
51DECLARE_RWSEM(nommu_vma_sem);
52
53struct vm_operations_struct generic_file_vm_ops = {
54};
55
Greg Ungerer66aa2b42005-09-12 11:18:10 +100056EXPORT_SYMBOL(vfree);
57EXPORT_SYMBOL(vmalloc_to_page);
58EXPORT_SYMBOL(vmalloc_32);
Luke Yang7a9166e2006-02-20 18:28:07 -080059EXPORT_SYMBOL(vmap);
60EXPORT_SYMBOL(vunmap);
Greg Ungerer66aa2b42005-09-12 11:18:10 +100061
Linus Torvalds1da177e2005-04-16 15:20:36 -070062/*
63 * Handle all mappings that got truncated by a "truncate()"
64 * system call.
65 *
66 * NOTE! We have to be ready to update the memory sharing
67 * between the file and the memory map for a potential last
68 * incomplete page. Ugly, but necessary.
69 */
70int vmtruncate(struct inode *inode, loff_t offset)
71{
72 struct address_space *mapping = inode->i_mapping;
73 unsigned long limit;
74
75 if (inode->i_size < offset)
76 goto do_expand;
77 i_size_write(inode, offset);
78
79 truncate_inode_pages(mapping, offset);
80 goto out_truncate;
81
82do_expand:
83 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
84 if (limit != RLIM_INFINITY && offset > limit)
85 goto out_sig;
86 if (offset > inode->i_sb->s_maxbytes)
87 goto out;
88 i_size_write(inode, offset);
89
90out_truncate:
91 if (inode->i_op && inode->i_op->truncate)
92 inode->i_op->truncate(inode);
93 return 0;
94out_sig:
95 send_sig(SIGXFSZ, current, 0);
96out:
97 return -EFBIG;
98}
99
100EXPORT_SYMBOL(vmtruncate);
101
102/*
103 * Return the total memory allocated for this pointer, not
104 * just what the caller asked for.
105 *
106 * Doesn't have to be accurate, i.e. may have races.
107 */
108unsigned int kobjsize(const void *objp)
109{
110 struct page *page;
111
112 if (!objp || !((page = virt_to_page(objp))))
113 return 0;
114
115 if (PageSlab(page))
116 return ksize(objp);
117
118 BUG_ON(page->index < 0);
119 BUG_ON(page->index >= MAX_ORDER);
120
121 return (PAGE_SIZE << page->index);
122}
123
124/*
David Howells7b4d5b82006-09-27 01:50:18 -0700125 * get a list of pages in an address range belonging to the specified process
126 * and indicate the VMA that covers each page
127 * - this is potentially dodgy as we may end incrementing the page count of a
128 * slab page or a secondary page from a compound page
129 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 */
131int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
132 unsigned long start, int len, int write, int force,
133 struct page **pages, struct vm_area_struct **vmas)
134{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700135 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700136 unsigned long vm_flags;
137 int i;
138
139 /* calculate required read or write permissions.
140 * - if 'force' is set, we only require the "MAY" flags.
141 */
142 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
143 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700146 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700147 if (!vma)
148 goto finish_or_fault;
149
150 /* protect what we can, including chardevs */
151 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
152 !(vm_flags & vma->vm_flags))
153 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 if (pages) {
156 pages[i] = virt_to_page(start);
157 if (pages[i])
158 page_cache_get(pages[i]);
159 }
160 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700161 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 start += PAGE_SIZE;
163 }
David Howells7b4d5b82006-09-27 01:50:18 -0700164
165 return i;
166
167finish_or_fault:
168 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169}
170
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000171EXPORT_SYMBOL(get_user_pages);
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173DEFINE_RWLOCK(vmlist_lock);
174struct vm_struct *vmlist;
175
176void vfree(void *addr)
177{
178 kfree(addr);
179}
180
Al Virodd0fc662005-10-07 07:46:04 +0100181void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 /*
184 * kmalloc doesn't like __GFP_HIGHMEM for some reason
185 */
Nick Piggin84097512006-03-22 00:08:34 -0800186 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
189struct page * vmalloc_to_page(void *addr)
190{
191 return virt_to_page(addr);
192}
193
194unsigned long vmalloc_to_pfn(void *addr)
195{
196 return page_to_pfn(virt_to_page(addr));
197}
198
199
200long vread(char *buf, char *addr, unsigned long count)
201{
202 memcpy(buf, addr, count);
203 return count;
204}
205
206long vwrite(char *buf, char *addr, unsigned long count)
207{
208 /* Don't allow overflow */
209 if ((unsigned long) addr + count < count)
210 count = -(unsigned long) addr;
211
212 memcpy(addr, buf, count);
213 return(count);
214}
215
216/*
217 * vmalloc - allocate virtually continguos memory
218 *
219 * @size: allocation size
220 *
221 * Allocate enough pages to cover @size from the page level
222 * allocator and map them into continguos kernel virtual space.
223 *
224 * For tight cotrol over page level allocator and protection flags
225 * use __vmalloc() instead.
226 */
227void *vmalloc(unsigned long size)
228{
229 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
230}
Andrew Mortonf6138882006-02-28 16:59:18 -0800231EXPORT_SYMBOL(vmalloc);
232
233void *vmalloc_node(unsigned long size, int node)
234{
235 return vmalloc(size);
236}
237EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
239/*
240 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
241 *
242 * @size: allocation size
243 *
244 * Allocate enough 32bit PA addressable pages to cover @size from the
245 * page level allocator and map them into continguos kernel virtual space.
246 */
247void *vmalloc_32(unsigned long size)
248{
249 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
250}
251
252void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
253{
254 BUG();
255 return NULL;
256}
257
258void vunmap(void *addr)
259{
260 BUG();
261}
262
263/*
264 * sys_brk() for the most part doesn't need the global kernel
265 * lock, except when an application is doing something nasty
266 * like trying to un-brk an area that has already been mapped
267 * to a regular file. in this case, the unmapping will need
268 * to invoke file system routines that need the global lock.
269 */
270asmlinkage unsigned long sys_brk(unsigned long brk)
271{
272 struct mm_struct *mm = current->mm;
273
274 if (brk < mm->start_brk || brk > mm->context.end_brk)
275 return mm->brk;
276
277 if (mm->brk == brk)
278 return mm->brk;
279
280 /*
281 * Always allow shrinking brk
282 */
283 if (brk <= mm->brk) {
284 mm->brk = brk;
285 return brk;
286 }
287
288 /*
289 * Ok, looks good - let it rip.
290 */
291 return mm->brk = brk;
292}
293
294#ifdef DEBUG
295static void show_process_blocks(void)
296{
297 struct vm_list_struct *vml;
298
299 printk("Process blocks %d:", current->pid);
300
301 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
302 printk(" %p: %p", vml, vml->vma);
303 if (vml->vma)
304 printk(" (%d @%lx #%d)",
305 kobjsize((void *) vml->vma->vm_start),
306 vml->vma->vm_start,
307 atomic_read(&vml->vma->vm_usage));
308 printk(vml->next ? " ->" : ".\n");
309 }
310}
311#endif /* DEBUG */
312
313static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
314{
315 struct vm_area_struct *vma;
316 struct rb_node *n = nommu_vma_tree.rb_node;
317
318 while (n) {
319 vma = rb_entry(n, struct vm_area_struct, vm_rb);
320
321 if (start < vma->vm_start)
322 n = n->rb_left;
323 else if (start > vma->vm_start)
324 n = n->rb_right;
325 else
326 return vma;
327 }
328
329 return NULL;
330}
331
332static void add_nommu_vma(struct vm_area_struct *vma)
333{
334 struct vm_area_struct *pvma;
335 struct address_space *mapping;
336 struct rb_node **p = &nommu_vma_tree.rb_node;
337 struct rb_node *parent = NULL;
338
339 /* add the VMA to the mapping */
340 if (vma->vm_file) {
341 mapping = vma->vm_file->f_mapping;
342
343 flush_dcache_mmap_lock(mapping);
344 vma_prio_tree_insert(vma, &mapping->i_mmap);
345 flush_dcache_mmap_unlock(mapping);
346 }
347
348 /* add the VMA to the master list */
349 while (*p) {
350 parent = *p;
351 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
352
353 if (vma->vm_start < pvma->vm_start) {
354 p = &(*p)->rb_left;
355 }
356 else if (vma->vm_start > pvma->vm_start) {
357 p = &(*p)->rb_right;
358 }
359 else {
360 /* mappings are at the same address - this can only
361 * happen for shared-mem chardevs and shared file
362 * mappings backed by ramfs/tmpfs */
363 BUG_ON(!(pvma->vm_flags & VM_SHARED));
364
365 if (vma < pvma)
366 p = &(*p)->rb_left;
367 else if (vma > pvma)
368 p = &(*p)->rb_right;
369 else
370 BUG();
371 }
372 }
373
374 rb_link_node(&vma->vm_rb, parent, p);
375 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
376}
377
378static void delete_nommu_vma(struct vm_area_struct *vma)
379{
380 struct address_space *mapping;
381
382 /* remove the VMA from the mapping */
383 if (vma->vm_file) {
384 mapping = vma->vm_file->f_mapping;
385
386 flush_dcache_mmap_lock(mapping);
387 vma_prio_tree_remove(vma, &mapping->i_mmap);
388 flush_dcache_mmap_unlock(mapping);
389 }
390
391 /* remove from the master list */
392 rb_erase(&vma->vm_rb, &nommu_vma_tree);
393}
394
395/*
396 * determine whether a mapping should be permitted and, if so, what sort of
397 * mapping we're capable of supporting
398 */
399static int validate_mmap_request(struct file *file,
400 unsigned long addr,
401 unsigned long len,
402 unsigned long prot,
403 unsigned long flags,
404 unsigned long pgoff,
405 unsigned long *_capabilities)
406{
407 unsigned long capabilities;
408 unsigned long reqprot = prot;
409 int ret;
410
411 /* do the simple checks first */
412 if (flags & MAP_FIXED || addr) {
413 printk(KERN_DEBUG
414 "%d: Can't do fixed-address/overlay mmap of RAM\n",
415 current->pid);
416 return -EINVAL;
417 }
418
419 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
420 (flags & MAP_TYPE) != MAP_SHARED)
421 return -EINVAL;
422
423 if (PAGE_ALIGN(len) == 0)
424 return addr;
425
426 if (len > TASK_SIZE)
427 return -EINVAL;
428
429 /* offset overflow? */
430 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
431 return -EINVAL;
432
433 if (file) {
434 /* validate file mapping requests */
435 struct address_space *mapping;
436
437 /* files must support mmap */
438 if (!file->f_op || !file->f_op->mmap)
439 return -ENODEV;
440
441 /* work out if what we've got could possibly be shared
442 * - we support chardevs that provide their own "memory"
443 * - we support files/blockdevs that are memory backed
444 */
445 mapping = file->f_mapping;
446 if (!mapping)
447 mapping = file->f_dentry->d_inode->i_mapping;
448
449 capabilities = 0;
450 if (mapping && mapping->backing_dev_info)
451 capabilities = mapping->backing_dev_info->capabilities;
452
453 if (!capabilities) {
454 /* no explicit capabilities set, so assume some
455 * defaults */
456 switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
457 case S_IFREG:
458 case S_IFBLK:
459 capabilities = BDI_CAP_MAP_COPY;
460 break;
461
462 case S_IFCHR:
463 capabilities =
464 BDI_CAP_MAP_DIRECT |
465 BDI_CAP_READ_MAP |
466 BDI_CAP_WRITE_MAP;
467 break;
468
469 default:
470 return -EINVAL;
471 }
472 }
473
474 /* eliminate any capabilities that we can't support on this
475 * device */
476 if (!file->f_op->get_unmapped_area)
477 capabilities &= ~BDI_CAP_MAP_DIRECT;
478 if (!file->f_op->read)
479 capabilities &= ~BDI_CAP_MAP_COPY;
480
481 if (flags & MAP_SHARED) {
482 /* do checks for writing, appending and locking */
483 if ((prot & PROT_WRITE) &&
484 !(file->f_mode & FMODE_WRITE))
485 return -EACCES;
486
487 if (IS_APPEND(file->f_dentry->d_inode) &&
488 (file->f_mode & FMODE_WRITE))
489 return -EACCES;
490
491 if (locks_verify_locked(file->f_dentry->d_inode))
492 return -EAGAIN;
493
494 if (!(capabilities & BDI_CAP_MAP_DIRECT))
495 return -ENODEV;
496
497 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
498 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
499 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
500 ) {
501 printk("MAP_SHARED not completely supported on !MMU\n");
502 return -EINVAL;
503 }
504
505 /* we mustn't privatise shared mappings */
506 capabilities &= ~BDI_CAP_MAP_COPY;
507 }
508 else {
509 /* we're going to read the file into private memory we
510 * allocate */
511 if (!(capabilities & BDI_CAP_MAP_COPY))
512 return -ENODEV;
513
514 /* we don't permit a private writable mapping to be
515 * shared with the backing device */
516 if (prot & PROT_WRITE)
517 capabilities &= ~BDI_CAP_MAP_DIRECT;
518 }
519
520 /* handle executable mappings and implied executable
521 * mappings */
522 if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
523 if (prot & PROT_EXEC)
524 return -EPERM;
525 }
526 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
527 /* handle implication of PROT_EXEC by PROT_READ */
528 if (current->personality & READ_IMPLIES_EXEC) {
529 if (capabilities & BDI_CAP_EXEC_MAP)
530 prot |= PROT_EXEC;
531 }
532 }
533 else if ((prot & PROT_READ) &&
534 (prot & PROT_EXEC) &&
535 !(capabilities & BDI_CAP_EXEC_MAP)
536 ) {
537 /* backing file is not executable, try to copy */
538 capabilities &= ~BDI_CAP_MAP_DIRECT;
539 }
540 }
541 else {
542 /* anonymous mappings are always memory backed and can be
543 * privately mapped
544 */
545 capabilities = BDI_CAP_MAP_COPY;
546
547 /* handle PROT_EXEC implication by PROT_READ */
548 if ((prot & PROT_READ) &&
549 (current->personality & READ_IMPLIES_EXEC))
550 prot |= PROT_EXEC;
551 }
552
553 /* allow the security API to have its say */
554 ret = security_file_mmap(file, reqprot, prot, flags);
555 if (ret < 0)
556 return ret;
557
558 /* looks okay */
559 *_capabilities = capabilities;
560 return 0;
561}
562
563/*
564 * we've determined that we can make the mapping, now translate what we
565 * now know into VMA flags
566 */
567static unsigned long determine_vm_flags(struct file *file,
568 unsigned long prot,
569 unsigned long flags,
570 unsigned long capabilities)
571{
572 unsigned long vm_flags;
573
574 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
575 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
576 /* vm_flags |= mm->def_flags; */
577
578 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
579 /* attempt to share read-only copies of mapped file chunks */
580 if (file && !(prot & PROT_WRITE))
581 vm_flags |= VM_MAYSHARE;
582 }
583 else {
584 /* overlay a shareable mapping on the backing device or inode
585 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
586 * romfs/cramfs */
587 if (flags & MAP_SHARED)
588 vm_flags |= VM_MAYSHARE | VM_SHARED;
589 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
590 vm_flags |= VM_MAYSHARE;
591 }
592
593 /* refuse to let anyone share private mappings with this process if
594 * it's being traced - otherwise breakpoints set in it may interfere
595 * with another untraced process
596 */
597 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
598 vm_flags &= ~VM_MAYSHARE;
599
600 return vm_flags;
601}
602
603/*
604 * set up a shared mapping on a file
605 */
606static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
607{
608 int ret;
609
610 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
611 if (ret != -ENOSYS)
612 return ret;
613
614 /* getting an ENOSYS error indicates that direct mmap isn't
615 * possible (as opposed to tried but failed) so we'll fall
616 * through to making a private copy of the data and mapping
617 * that if we can */
618 return -ENODEV;
619}
620
621/*
622 * set up a private mapping or an anonymous shared mapping
623 */
624static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
625{
626 void *base;
627 int ret;
628
629 /* invoke the file's mapping function so that it can keep track of
630 * shared mappings on devices or memory
631 * - VM_MAYSHARE will be set if it may attempt to share
632 */
633 if (vma->vm_file) {
634 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
635 if (ret != -ENOSYS) {
636 /* shouldn't return success if we're not sharing */
637 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
638 return ret; /* success or a real error */
639 }
640
641 /* getting an ENOSYS error indicates that direct mmap isn't
642 * possible (as opposed to tried but failed) so we'll try to
643 * make a private copy of the data and map that instead */
644 }
645
646 /* allocate some memory to hold the mapping
647 * - note that this may not return a page-aligned address if the object
648 * we're allocating is smaller than a page
649 */
Nick Piggin84097512006-03-22 00:08:34 -0800650 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 if (!base)
652 goto enomem;
653
654 vma->vm_start = (unsigned long) base;
655 vma->vm_end = vma->vm_start + len;
656 vma->vm_flags |= VM_MAPPED_COPY;
657
658#ifdef WARN_ON_SLACK
659 if (len + WARN_ON_SLACK <= kobjsize(result))
660 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
661 len, current->pid, kobjsize(result) - len);
662#endif
663
664 if (vma->vm_file) {
665 /* read the contents of a file into the copy */
666 mm_segment_t old_fs;
667 loff_t fpos;
668
669 fpos = vma->vm_pgoff;
670 fpos <<= PAGE_SHIFT;
671
672 old_fs = get_fs();
673 set_fs(KERNEL_DS);
674 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
675 set_fs(old_fs);
676
677 if (ret < 0)
678 goto error_free;
679
680 /* clear the last little bit */
681 if (ret < len)
682 memset(base + ret, 0, len - ret);
683
684 } else {
685 /* if it's an anonymous mapping, then just clear it */
686 memset(base, 0, len);
687 }
688
689 return 0;
690
691error_free:
692 kfree(base);
693 vma->vm_start = 0;
694 return ret;
695
696enomem:
697 printk("Allocation of length %lu from process %d failed\n",
698 len, current->pid);
699 show_free_areas();
700 return -ENOMEM;
701}
702
703/*
704 * handle mapping creation for uClinux
705 */
706unsigned long do_mmap_pgoff(struct file *file,
707 unsigned long addr,
708 unsigned long len,
709 unsigned long prot,
710 unsigned long flags,
711 unsigned long pgoff)
712{
713 struct vm_list_struct *vml = NULL;
714 struct vm_area_struct *vma = NULL;
715 struct rb_node *rb;
716 unsigned long capabilities, vm_flags;
717 void *result;
718 int ret;
719
720 /* decide whether we should attempt the mapping, and if so what sort of
721 * mapping */
722 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
723 &capabilities);
724 if (ret < 0)
725 return ret;
726
727 /* we've determined that we can make the mapping, now translate what we
728 * now know into VMA flags */
729 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
730
731 /* we're going to need to record the mapping if it works */
732 vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
733 if (!vml)
734 goto error_getting_vml;
735 memset(vml, 0, sizeof(*vml));
736
737 down_write(&nommu_vma_sem);
738
739 /* if we want to share, we need to check for VMAs created by other
740 * mmap() calls that overlap with our proposed mapping
741 * - we can only share with an exact match on most regular files
742 * - shared mappings on character devices and memory backed files are
743 * permitted to overlap inexactly as far as we are concerned for in
744 * these cases, sharing is handled in the driver or filesystem rather
745 * than here
746 */
747 if (vm_flags & VM_MAYSHARE) {
748 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
749 unsigned long vmpglen;
750
751 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
752 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
753
754 if (!(vma->vm_flags & VM_MAYSHARE))
755 continue;
756
757 /* search for overlapping mappings on the same file */
758 if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
759 continue;
760
761 if (vma->vm_pgoff >= pgoff + pglen)
762 continue;
763
764 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
765 vmpglen >>= PAGE_SHIFT;
766 if (pgoff >= vma->vm_pgoff + vmpglen)
767 continue;
768
769 /* handle inexactly overlapping matches between mappings */
770 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
771 if (!(capabilities & BDI_CAP_MAP_DIRECT))
772 goto sharing_violation;
773 continue;
774 }
775
776 /* we've found a VMA we can share */
777 atomic_inc(&vma->vm_usage);
778
779 vml->vma = vma;
780 result = (void *) vma->vm_start;
781 goto shared;
782 }
783
784 vma = NULL;
785
786 /* obtain the address at which to make a shared mapping
787 * - this is the hook for quasi-memory character devices to
788 * tell us the location of a shared mapping
789 */
790 if (file && file->f_op->get_unmapped_area) {
791 addr = file->f_op->get_unmapped_area(file, addr, len,
792 pgoff, flags);
793 if (IS_ERR((void *) addr)) {
794 ret = addr;
795 if (ret != (unsigned long) -ENOSYS)
796 goto error;
797
798 /* the driver refused to tell us where to site
799 * the mapping so we'll have to attempt to copy
800 * it */
801 ret = (unsigned long) -ENODEV;
802 if (!(capabilities & BDI_CAP_MAP_COPY))
803 goto error;
804
805 capabilities &= ~BDI_CAP_MAP_DIRECT;
806 }
807 }
808 }
809
810 /* we're going to need a VMA struct as well */
811 vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
812 if (!vma)
813 goto error_getting_vma;
814
815 memset(vma, 0, sizeof(*vma));
816 INIT_LIST_HEAD(&vma->anon_vma_node);
817 atomic_set(&vma->vm_usage, 1);
818 if (file)
819 get_file(file);
820 vma->vm_file = file;
821 vma->vm_flags = vm_flags;
822 vma->vm_start = addr;
823 vma->vm_end = addr + len;
824 vma->vm_pgoff = pgoff;
825
826 vml->vma = vma;
827
828 /* set up the mapping */
829 if (file && vma->vm_flags & VM_SHARED)
830 ret = do_mmap_shared_file(vma, len);
831 else
832 ret = do_mmap_private(vma, len);
833 if (ret < 0)
834 goto error;
835
836 /* okay... we have a mapping; now we have to register it */
837 result = (void *) vma->vm_start;
838
839 if (vma->vm_flags & VM_MAPPED_COPY) {
840 realalloc += kobjsize(result);
841 askedalloc += len;
842 }
843
844 realalloc += kobjsize(vma);
845 askedalloc += sizeof(*vma);
846
847 current->mm->total_vm += len >> PAGE_SHIFT;
848
849 add_nommu_vma(vma);
850
851 shared:
852 realalloc += kobjsize(vml);
853 askedalloc += sizeof(*vml);
854
855 vml->next = current->mm->context.vmlist;
856 current->mm->context.vmlist = vml;
857
858 up_write(&nommu_vma_sem);
859
860 if (prot & PROT_EXEC)
861 flush_icache_range((unsigned long) result,
862 (unsigned long) result + len);
863
864#ifdef DEBUG
865 printk("do_mmap:\n");
866 show_process_blocks();
867#endif
868
869 return (unsigned long) result;
870
871 error:
872 up_write(&nommu_vma_sem);
873 kfree(vml);
874 if (vma) {
875 fput(vma->vm_file);
876 kfree(vma);
877 }
878 return ret;
879
880 sharing_violation:
881 up_write(&nommu_vma_sem);
882 printk("Attempt to share mismatched mappings\n");
883 kfree(vml);
884 return -EINVAL;
885
886 error_getting_vma:
887 up_write(&nommu_vma_sem);
888 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000889 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 len, current->pid);
891 show_free_areas();
892 return -ENOMEM;
893
894 error_getting_vml:
895 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
896 len, current->pid);
897 show_free_areas();
898 return -ENOMEM;
899}
900
901/*
902 * handle mapping disposal for uClinux
903 */
904static void put_vma(struct vm_area_struct *vma)
905{
906 if (vma) {
907 down_write(&nommu_vma_sem);
908
909 if (atomic_dec_and_test(&vma->vm_usage)) {
910 delete_nommu_vma(vma);
911
912 if (vma->vm_ops && vma->vm_ops->close)
913 vma->vm_ops->close(vma);
914
915 /* IO memory and memory shared directly out of the pagecache from
916 * ramfs/tmpfs mustn't be released here */
917 if (vma->vm_flags & VM_MAPPED_COPY) {
918 realalloc -= kobjsize((void *) vma->vm_start);
919 askedalloc -= vma->vm_end - vma->vm_start;
920 kfree((void *) vma->vm_start);
921 }
922
923 realalloc -= kobjsize(vma);
924 askedalloc -= sizeof(*vma);
925
926 if (vma->vm_file)
927 fput(vma->vm_file);
928 kfree(vma);
929 }
930
931 up_write(&nommu_vma_sem);
932 }
933}
934
935int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
936{
937 struct vm_list_struct *vml, **parent;
938 unsigned long end = addr + len;
939
940#ifdef DEBUG
941 printk("do_munmap:\n");
942#endif
943
944 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
945 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000946 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 goto found;
948
949 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
950 current->pid, current->comm, (void *) addr);
951 return -EINVAL;
952
953 found:
954 vml = *parent;
955
956 put_vma(vml->vma);
957
958 *parent = vml->next;
959 realalloc -= kobjsize(vml);
960 askedalloc -= sizeof(*vml);
961 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700962
963 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 mm->total_vm -= len >> PAGE_SHIFT;
965
966#ifdef DEBUG
967 show_process_blocks();
968#endif
969
970 return 0;
971}
972
973/* Release all mmaps. */
974void exit_mmap(struct mm_struct * mm)
975{
976 struct vm_list_struct *tmp;
977
978 if (mm) {
979#ifdef DEBUG
980 printk("Exit_mmap:\n");
981#endif
982
983 mm->total_vm = 0;
984
985 while ((tmp = mm->context.vmlist)) {
986 mm->context.vmlist = tmp->next;
987 put_vma(tmp->vma);
988
989 realalloc -= kobjsize(tmp);
990 askedalloc -= sizeof(*tmp);
991 kfree(tmp);
992 }
993
994#ifdef DEBUG
995 show_process_blocks();
996#endif
997 }
998}
999
1000asmlinkage long sys_munmap(unsigned long addr, size_t len)
1001{
1002 int ret;
1003 struct mm_struct *mm = current->mm;
1004
1005 down_write(&mm->mmap_sem);
1006 ret = do_munmap(mm, addr, len);
1007 up_write(&mm->mmap_sem);
1008 return ret;
1009}
1010
1011unsigned long do_brk(unsigned long addr, unsigned long len)
1012{
1013 return -ENOMEM;
1014}
1015
1016/*
1017 * Expand (or shrink) an existing mapping, potentially moving it at the
1018 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1019 *
1020 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
1021 * This option implies MREMAP_MAYMOVE.
1022 *
1023 * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
1024 * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
1025 */
1026unsigned long do_mremap(unsigned long addr,
1027 unsigned long old_len, unsigned long new_len,
1028 unsigned long flags, unsigned long new_addr)
1029{
1030 struct vm_list_struct *vml = NULL;
1031
1032 /* insanity checks first */
1033 if (new_len == 0)
1034 return (unsigned long) -EINVAL;
1035
1036 if (flags & MREMAP_FIXED && new_addr != addr)
1037 return (unsigned long) -EINVAL;
1038
1039 for (vml = current->mm->context.vmlist; vml; vml = vml->next)
1040 if (vml->vma->vm_start == addr)
1041 goto found;
1042
1043 return (unsigned long) -EINVAL;
1044
1045 found:
1046 if (vml->vma->vm_end != vml->vma->vm_start + old_len)
1047 return (unsigned long) -EFAULT;
1048
1049 if (vml->vma->vm_flags & VM_MAYSHARE)
1050 return (unsigned long) -EPERM;
1051
1052 if (new_len > kobjsize((void *) addr))
1053 return (unsigned long) -ENOMEM;
1054
1055 /* all checks complete - do it */
1056 vml->vma->vm_end = vml->vma->vm_start + new_len;
1057
1058 askedalloc -= old_len;
1059 askedalloc += new_len;
1060
1061 return vml->vma->vm_start;
1062}
1063
1064/*
1065 * Look up the first VMA which satisfies addr < vm_end, NULL if none
David Howells0159b142006-09-27 01:50:16 -07001066 * - should be called with mm->mmap_sem at least readlocked
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 */
1068struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1069{
1070 struct vm_list_struct *vml;
1071
1072 for (vml = mm->context.vmlist; vml; vml = vml->next)
1073 if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
1074 return vml->vma;
1075
1076 return NULL;
1077}
1078
1079EXPORT_SYMBOL(find_vma);
1080
Linus Torvalds6aab3412005-11-28 14:34:23 -08001081struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001082 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083{
1084 return NULL;
1085}
1086
1087struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1088{
1089 return NULL;
1090}
1091
1092int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1093 unsigned long to, unsigned long size, pgprot_t prot)
1094{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001095 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1096 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097}
Luke Yang22c4af42006-07-14 00:24:09 -07001098EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
1100void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1101{
1102}
1103
1104unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1105 unsigned long len, unsigned long pgoff, unsigned long flags)
1106{
1107 return -ENOMEM;
1108}
1109
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001110void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111{
1112}
1113
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114void unmap_mapping_range(struct address_space *mapping,
1115 loff_t const holebegin, loff_t const holelen,
1116 int even_cows)
1117{
1118}
Luke Yang22c4af42006-07-14 00:24:09 -07001119EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120
1121/*
1122 * Check that a process has enough memory to allocate a new virtual
1123 * mapping. 0 means there is enough memory for the allocation to
1124 * succeed and -ENOMEM implies there is not.
1125 *
1126 * We currently support three overcommit policies, which are set via the
1127 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1128 *
1129 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1130 * Additional code 2002 Jul 20 by Robert Love.
1131 *
1132 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1133 *
1134 * Note this is a helper function intended to be used by LSMs which
1135 * wish to use this logic.
1136 */
1137int __vm_enough_memory(long pages, int cap_sys_admin)
1138{
1139 unsigned long free, allowed;
1140
1141 vm_acct_memory(pages);
1142
1143 /*
1144 * Sometimes we want to use more memory than we have
1145 */
1146 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1147 return 0;
1148
1149 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1150 unsigned long n;
1151
Christoph Lameter347ce432006-06-30 01:55:35 -07001152 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 free += nr_swap_pages;
1154
1155 /*
1156 * Any slabs which are created with the
1157 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1158 * which are reclaimable, under pressure. The dentry
1159 * cache and most inode caches should fall into this
1160 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001161 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
1163 /*
1164 * Leave the last 3% for root
1165 */
1166 if (!cap_sys_admin)
1167 free -= free / 32;
1168
1169 if (free > pages)
1170 return 0;
1171
1172 /*
1173 * nr_free_pages() is very expensive on large systems,
1174 * only call if we're about to fail.
1175 */
1176 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001177
1178 /*
1179 * Leave reserved pages. The pages are not for anonymous pages.
1180 */
1181 if (n <= totalreserve_pages)
1182 goto error;
1183 else
1184 n -= totalreserve_pages;
1185
1186 /*
1187 * Leave the last 3% for root
1188 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 if (!cap_sys_admin)
1190 n -= n / 32;
1191 free += n;
1192
1193 if (free > pages)
1194 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001195
1196 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 }
1198
1199 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1200 /*
1201 * Leave the last 3% for root
1202 */
1203 if (!cap_sys_admin)
1204 allowed -= allowed / 32;
1205 allowed += total_swap_pages;
1206
1207 /* Don't let a single process grow too big:
1208 leave 3% of the size of this process for other processes */
1209 allowed -= current->mm->total_vm / 32;
1210
Simon Derr2f60f8d2005-08-04 19:52:03 -07001211 /*
1212 * cast `allowed' as a signed long because vm_committed_space
1213 * sometimes has a negative value
1214 */
1215 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001217error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 vm_unacct_memory(pages);
1219
1220 return -ENOMEM;
1221}
1222
1223int in_gate_area_no_task(unsigned long addr)
1224{
1225 return 0;
1226}
David Howellsb0e15192006-01-06 00:11:42 -08001227
1228struct page *filemap_nopage(struct vm_area_struct *area,
1229 unsigned long address, int *type)
1230{
1231 BUG();
1232 return NULL;
1233}
David Howells0ec76a12006-09-27 01:50:15 -07001234
1235/*
1236 * Access another process' address space.
1237 * - source/target buffer must be kernel space
1238 */
1239int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1240{
David Howells0ec76a12006-09-27 01:50:15 -07001241 struct vm_area_struct *vma;
1242 struct mm_struct *mm;
1243
1244 if (addr + len < addr)
1245 return 0;
1246
1247 mm = get_task_mm(tsk);
1248 if (!mm)
1249 return 0;
1250
1251 down_read(&mm->mmap_sem);
1252
1253 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001254 vma = find_vma(mm, addr);
1255 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001256 /* don't overrun this mapping */
1257 if (addr + len >= vma->vm_end)
1258 len = vma->vm_end - addr;
1259
1260 /* only read or write mappings where it is permitted */
1261 if (write && vma->vm_flags & VM_WRITE)
1262 len -= copy_to_user((void *) addr, buf, len);
1263 else if (!write && vma->vm_flags & VM_READ)
1264 len -= copy_from_user(buf, (void *) addr, len);
1265 else
1266 len = 0;
1267 } else {
1268 len = 0;
1269 }
1270
1271 up_read(&mm->mmap_sem);
1272 mmput(mm);
1273 return len;
1274}