blob: 8ed0cb43118a1fc0586b165b49e6ad8e7c8a8efb [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);
Wu, Bryan6a04de62007-04-11 23:28:47 -070048EXPORT_SYMBOL(num_physpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50/* list of shareable VMAs */
51struct rb_root nommu_vma_tree = RB_ROOT;
52DECLARE_RWSEM(nommu_vma_sem);
53
54struct vm_operations_struct generic_file_vm_ops = {
55};
56
57/*
58 * Handle all mappings that got truncated by a "truncate()"
59 * system call.
60 *
61 * NOTE! We have to be ready to update the memory sharing
62 * between the file and the memory map for a potential last
63 * incomplete page. Ugly, but necessary.
64 */
65int vmtruncate(struct inode *inode, loff_t offset)
66{
67 struct address_space *mapping = inode->i_mapping;
68 unsigned long limit;
69
70 if (inode->i_size < offset)
71 goto do_expand;
72 i_size_write(inode, offset);
73
74 truncate_inode_pages(mapping, offset);
75 goto out_truncate;
76
77do_expand:
78 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
79 if (limit != RLIM_INFINITY && offset > limit)
80 goto out_sig;
81 if (offset > inode->i_sb->s_maxbytes)
82 goto out;
83 i_size_write(inode, offset);
84
85out_truncate:
86 if (inode->i_op && inode->i_op->truncate)
87 inode->i_op->truncate(inode);
88 return 0;
89out_sig:
90 send_sig(SIGXFSZ, current, 0);
91out:
92 return -EFBIG;
93}
94
95EXPORT_SYMBOL(vmtruncate);
96
97/*
98 * Return the total memory allocated for this pointer, not
99 * just what the caller asked for.
100 *
101 * Doesn't have to be accurate, i.e. may have races.
102 */
103unsigned int kobjsize(const void *objp)
104{
105 struct page *page;
106
107 if (!objp || !((page = virt_to_page(objp))))
108 return 0;
109
110 if (PageSlab(page))
111 return ksize(objp);
112
113 BUG_ON(page->index < 0);
114 BUG_ON(page->index >= MAX_ORDER);
115
116 return (PAGE_SIZE << page->index);
117}
118
119/*
David Howells7b4d5b82006-09-27 01:50:18 -0700120 * get a list of pages in an address range belonging to the specified process
121 * and indicate the VMA that covers each page
122 * - this is potentially dodgy as we may end incrementing the page count of a
123 * slab page or a secondary page from a compound page
124 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 */
126int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
127 unsigned long start, int len, int write, int force,
128 struct page **pages, struct vm_area_struct **vmas)
129{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700130 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700131 unsigned long vm_flags;
132 int i;
133
134 /* calculate required read or write permissions.
135 * - if 'force' is set, we only require the "MAY" flags.
136 */
137 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
138 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
140 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700141 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700142 if (!vma)
143 goto finish_or_fault;
144
145 /* protect what we can, including chardevs */
146 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
147 !(vm_flags & vma->vm_flags))
148 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700149
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 if (pages) {
151 pages[i] = virt_to_page(start);
152 if (pages[i])
153 page_cache_get(pages[i]);
154 }
155 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700156 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 start += PAGE_SIZE;
158 }
David Howells7b4d5b82006-09-27 01:50:18 -0700159
160 return i;
161
162finish_or_fault:
163 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000165EXPORT_SYMBOL(get_user_pages);
166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167DEFINE_RWLOCK(vmlist_lock);
168struct vm_struct *vmlist;
169
170void vfree(void *addr)
171{
172 kfree(addr);
173}
Paul Mundtb5073172007-07-21 04:37:25 -0700174EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
Al Virodd0fc662005-10-07 07:46:04 +0100176void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177{
178 /*
179 * kmalloc doesn't like __GFP_HIGHMEM for some reason
180 */
Nick Piggin84097512006-03-22 00:08:34 -0800181 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182}
Paul Mundtb5073172007-07-21 04:37:25 -0700183EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
185struct page * vmalloc_to_page(void *addr)
186{
187 return virt_to_page(addr);
188}
Paul Mundtb5073172007-07-21 04:37:25 -0700189EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
191unsigned long vmalloc_to_pfn(void *addr)
192{
193 return page_to_pfn(virt_to_page(addr));
194}
Paul Mundtb5073172007-07-21 04:37:25 -0700195EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
197long vread(char *buf, char *addr, unsigned long count)
198{
199 memcpy(buf, addr, count);
200 return count;
201}
202
203long vwrite(char *buf, char *addr, unsigned long count)
204{
205 /* Don't allow overflow */
206 if ((unsigned long) addr + count < count)
207 count = -(unsigned long) addr;
208
209 memcpy(addr, buf, count);
210 return(count);
211}
212
213/*
214 * vmalloc - allocate virtually continguos memory
215 *
216 * @size: allocation size
217 *
218 * Allocate enough pages to cover @size from the page level
219 * allocator and map them into continguos kernel virtual space.
220 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200221 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 * use __vmalloc() instead.
223 */
224void *vmalloc(unsigned long size)
225{
226 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
227}
Andrew Mortonf6138882006-02-28 16:59:18 -0800228EXPORT_SYMBOL(vmalloc);
229
230void *vmalloc_node(unsigned long size, int node)
231{
232 return vmalloc(size);
233}
234EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Paul Mundtb5073172007-07-21 04:37:25 -0700236/**
237 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 * @size: allocation size
239 *
240 * Allocate enough 32bit PA addressable pages to cover @size from the
241 * page level allocator and map them into continguos kernel virtual space.
242 */
243void *vmalloc_32(unsigned long size)
244{
245 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
246}
Paul Mundtb5073172007-07-21 04:37:25 -0700247EXPORT_SYMBOL(vmalloc_32);
248
249/**
250 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
251 * @size: allocation size
252 *
253 * The resulting memory area is 32bit addressable and zeroed so it can be
254 * mapped to userspace without leaking data.
255 */
256void *vmalloc_32_user(unsigned long size)
257{
258 return __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
259}
260EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
263{
264 BUG();
265 return NULL;
266}
Paul Mundtb5073172007-07-21 04:37:25 -0700267EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
269void vunmap(void *addr)
270{
271 BUG();
272}
Paul Mundtb5073172007-07-21 04:37:25 -0700273EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700276 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
277 * have one.
278 */
279void __attribute__((weak)) vmalloc_sync_all(void)
280{
281}
282
Paul Mundtb5073172007-07-21 04:37:25 -0700283int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
284 struct page *page)
285{
286 return -EINVAL;
287}
288EXPORT_SYMBOL(vm_insert_page);
289
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700290/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 * sys_brk() for the most part doesn't need the global kernel
292 * lock, except when an application is doing something nasty
293 * like trying to un-brk an area that has already been mapped
294 * to a regular file. in this case, the unmapping will need
295 * to invoke file system routines that need the global lock.
296 */
297asmlinkage unsigned long sys_brk(unsigned long brk)
298{
299 struct mm_struct *mm = current->mm;
300
301 if (brk < mm->start_brk || brk > mm->context.end_brk)
302 return mm->brk;
303
304 if (mm->brk == brk)
305 return mm->brk;
306
307 /*
308 * Always allow shrinking brk
309 */
310 if (brk <= mm->brk) {
311 mm->brk = brk;
312 return brk;
313 }
314
315 /*
316 * Ok, looks good - let it rip.
317 */
318 return mm->brk = brk;
319}
320
321#ifdef DEBUG
322static void show_process_blocks(void)
323{
324 struct vm_list_struct *vml;
325
326 printk("Process blocks %d:", current->pid);
327
328 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
329 printk(" %p: %p", vml, vml->vma);
330 if (vml->vma)
331 printk(" (%d @%lx #%d)",
332 kobjsize((void *) vml->vma->vm_start),
333 vml->vma->vm_start,
334 atomic_read(&vml->vma->vm_usage));
335 printk(vml->next ? " ->" : ".\n");
336 }
337}
338#endif /* DEBUG */
339
David Howells30340972006-09-27 01:50:20 -0700340/*
341 * add a VMA into a process's mm_struct in the appropriate place in the list
342 * - should be called with mm->mmap_sem held writelocked
343 */
344static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
345{
346 struct vm_list_struct **ppv;
347
348 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
349 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
350 break;
351
352 vml->next = *ppv;
353 *ppv = vml;
354}
355
356/*
357 * look up the first VMA in which addr resides, NULL if none
358 * - should be called with mm->mmap_sem at least held readlocked
359 */
360struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
361{
362 struct vm_list_struct *loop, *vml;
363
364 /* search the vm_start ordered list */
365 vml = NULL;
366 for (loop = mm->context.vmlist; loop; loop = loop->next) {
367 if (loop->vma->vm_start > addr)
368 break;
369 vml = loop;
370 }
371
372 if (vml && vml->vma->vm_end > addr)
373 return vml->vma;
374
375 return NULL;
376}
377EXPORT_SYMBOL(find_vma);
378
379/*
David Howells930e6522006-09-27 01:50:22 -0700380 * find a VMA
381 * - we don't extend stack VMAs under NOMMU conditions
382 */
383struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
384{
385 return find_vma(mm, addr);
386}
387
Greg Ungerer57c8f632007-07-15 23:38:28 -0700388int expand_stack(struct vm_area_struct *vma, unsigned long address)
389{
390 return -ENOMEM;
391}
392
David Howells930e6522006-09-27 01:50:22 -0700393/*
David Howells6fa5f802006-09-27 01:50:21 -0700394 * look up the first VMA exactly that exactly matches addr
395 * - should be called with mm->mmap_sem at least held readlocked
396 */
397static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
398 unsigned long addr)
399{
400 struct vm_list_struct *vml;
401
402 /* search the vm_start ordered list */
403 for (vml = mm->context.vmlist; vml; vml = vml->next) {
404 if (vml->vma->vm_start == addr)
405 return vml->vma;
406 if (vml->vma->vm_start > addr)
407 break;
408 }
409
410 return NULL;
411}
412
413/*
David Howells30340972006-09-27 01:50:20 -0700414 * find a VMA in the global tree
415 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
417{
418 struct vm_area_struct *vma;
419 struct rb_node *n = nommu_vma_tree.rb_node;
420
421 while (n) {
422 vma = rb_entry(n, struct vm_area_struct, vm_rb);
423
424 if (start < vma->vm_start)
425 n = n->rb_left;
426 else if (start > vma->vm_start)
427 n = n->rb_right;
428 else
429 return vma;
430 }
431
432 return NULL;
433}
434
David Howells30340972006-09-27 01:50:20 -0700435/*
436 * add a VMA in the global tree
437 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438static void add_nommu_vma(struct vm_area_struct *vma)
439{
440 struct vm_area_struct *pvma;
441 struct address_space *mapping;
442 struct rb_node **p = &nommu_vma_tree.rb_node;
443 struct rb_node *parent = NULL;
444
445 /* add the VMA to the mapping */
446 if (vma->vm_file) {
447 mapping = vma->vm_file->f_mapping;
448
449 flush_dcache_mmap_lock(mapping);
450 vma_prio_tree_insert(vma, &mapping->i_mmap);
451 flush_dcache_mmap_unlock(mapping);
452 }
453
454 /* add the VMA to the master list */
455 while (*p) {
456 parent = *p;
457 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
458
459 if (vma->vm_start < pvma->vm_start) {
460 p = &(*p)->rb_left;
461 }
462 else if (vma->vm_start > pvma->vm_start) {
463 p = &(*p)->rb_right;
464 }
465 else {
466 /* mappings are at the same address - this can only
467 * happen for shared-mem chardevs and shared file
468 * mappings backed by ramfs/tmpfs */
469 BUG_ON(!(pvma->vm_flags & VM_SHARED));
470
471 if (vma < pvma)
472 p = &(*p)->rb_left;
473 else if (vma > pvma)
474 p = &(*p)->rb_right;
475 else
476 BUG();
477 }
478 }
479
480 rb_link_node(&vma->vm_rb, parent, p);
481 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
482}
483
David Howells30340972006-09-27 01:50:20 -0700484/*
485 * delete a VMA from the global list
486 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487static void delete_nommu_vma(struct vm_area_struct *vma)
488{
489 struct address_space *mapping;
490
491 /* remove the VMA from the mapping */
492 if (vma->vm_file) {
493 mapping = vma->vm_file->f_mapping;
494
495 flush_dcache_mmap_lock(mapping);
496 vma_prio_tree_remove(vma, &mapping->i_mmap);
497 flush_dcache_mmap_unlock(mapping);
498 }
499
500 /* remove from the master list */
501 rb_erase(&vma->vm_rb, &nommu_vma_tree);
502}
503
504/*
505 * determine whether a mapping should be permitted and, if so, what sort of
506 * mapping we're capable of supporting
507 */
508static int validate_mmap_request(struct file *file,
509 unsigned long addr,
510 unsigned long len,
511 unsigned long prot,
512 unsigned long flags,
513 unsigned long pgoff,
514 unsigned long *_capabilities)
515{
516 unsigned long capabilities;
517 unsigned long reqprot = prot;
518 int ret;
519
520 /* do the simple checks first */
521 if (flags & MAP_FIXED || addr) {
522 printk(KERN_DEBUG
523 "%d: Can't do fixed-address/overlay mmap of RAM\n",
524 current->pid);
525 return -EINVAL;
526 }
527
528 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
529 (flags & MAP_TYPE) != MAP_SHARED)
530 return -EINVAL;
531
Mike Frysingerf81cff02006-12-06 12:02:59 +1000532 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 return -EINVAL;
534
Mike Frysingerf81cff02006-12-06 12:02:59 +1000535 /* Careful about overflows.. */
536 len = PAGE_ALIGN(len);
537 if (!len || len > TASK_SIZE)
538 return -ENOMEM;
539
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 /* offset overflow? */
541 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000542 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
544 if (file) {
545 /* validate file mapping requests */
546 struct address_space *mapping;
547
548 /* files must support mmap */
549 if (!file->f_op || !file->f_op->mmap)
550 return -ENODEV;
551
552 /* work out if what we've got could possibly be shared
553 * - we support chardevs that provide their own "memory"
554 * - we support files/blockdevs that are memory backed
555 */
556 mapping = file->f_mapping;
557 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800558 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
560 capabilities = 0;
561 if (mapping && mapping->backing_dev_info)
562 capabilities = mapping->backing_dev_info->capabilities;
563
564 if (!capabilities) {
565 /* no explicit capabilities set, so assume some
566 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800567 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 case S_IFREG:
569 case S_IFBLK:
570 capabilities = BDI_CAP_MAP_COPY;
571 break;
572
573 case S_IFCHR:
574 capabilities =
575 BDI_CAP_MAP_DIRECT |
576 BDI_CAP_READ_MAP |
577 BDI_CAP_WRITE_MAP;
578 break;
579
580 default:
581 return -EINVAL;
582 }
583 }
584
585 /* eliminate any capabilities that we can't support on this
586 * device */
587 if (!file->f_op->get_unmapped_area)
588 capabilities &= ~BDI_CAP_MAP_DIRECT;
589 if (!file->f_op->read)
590 capabilities &= ~BDI_CAP_MAP_COPY;
591
592 if (flags & MAP_SHARED) {
593 /* do checks for writing, appending and locking */
594 if ((prot & PROT_WRITE) &&
595 !(file->f_mode & FMODE_WRITE))
596 return -EACCES;
597
Josef Sipeke9536ae2006-12-08 02:37:21 -0800598 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 (file->f_mode & FMODE_WRITE))
600 return -EACCES;
601
Josef Sipeke9536ae2006-12-08 02:37:21 -0800602 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 return -EAGAIN;
604
605 if (!(capabilities & BDI_CAP_MAP_DIRECT))
606 return -ENODEV;
607
608 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
609 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
610 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
611 ) {
612 printk("MAP_SHARED not completely supported on !MMU\n");
613 return -EINVAL;
614 }
615
616 /* we mustn't privatise shared mappings */
617 capabilities &= ~BDI_CAP_MAP_COPY;
618 }
619 else {
620 /* we're going to read the file into private memory we
621 * allocate */
622 if (!(capabilities & BDI_CAP_MAP_COPY))
623 return -ENODEV;
624
625 /* we don't permit a private writable mapping to be
626 * shared with the backing device */
627 if (prot & PROT_WRITE)
628 capabilities &= ~BDI_CAP_MAP_DIRECT;
629 }
630
631 /* handle executable mappings and implied executable
632 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800633 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 if (prot & PROT_EXEC)
635 return -EPERM;
636 }
637 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
638 /* handle implication of PROT_EXEC by PROT_READ */
639 if (current->personality & READ_IMPLIES_EXEC) {
640 if (capabilities & BDI_CAP_EXEC_MAP)
641 prot |= PROT_EXEC;
642 }
643 }
644 else if ((prot & PROT_READ) &&
645 (prot & PROT_EXEC) &&
646 !(capabilities & BDI_CAP_EXEC_MAP)
647 ) {
648 /* backing file is not executable, try to copy */
649 capabilities &= ~BDI_CAP_MAP_DIRECT;
650 }
651 }
652 else {
653 /* anonymous mappings are always memory backed and can be
654 * privately mapped
655 */
656 capabilities = BDI_CAP_MAP_COPY;
657
658 /* handle PROT_EXEC implication by PROT_READ */
659 if ((prot & PROT_READ) &&
660 (current->personality & READ_IMPLIES_EXEC))
661 prot |= PROT_EXEC;
662 }
663
664 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400665 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 if (ret < 0)
667 return ret;
668
669 /* looks okay */
670 *_capabilities = capabilities;
671 return 0;
672}
673
674/*
675 * we've determined that we can make the mapping, now translate what we
676 * now know into VMA flags
677 */
678static unsigned long determine_vm_flags(struct file *file,
679 unsigned long prot,
680 unsigned long flags,
681 unsigned long capabilities)
682{
683 unsigned long vm_flags;
684
685 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
686 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
687 /* vm_flags |= mm->def_flags; */
688
689 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
690 /* attempt to share read-only copies of mapped file chunks */
691 if (file && !(prot & PROT_WRITE))
692 vm_flags |= VM_MAYSHARE;
693 }
694 else {
695 /* overlay a shareable mapping on the backing device or inode
696 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
697 * romfs/cramfs */
698 if (flags & MAP_SHARED)
699 vm_flags |= VM_MAYSHARE | VM_SHARED;
700 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
701 vm_flags |= VM_MAYSHARE;
702 }
703
704 /* refuse to let anyone share private mappings with this process if
705 * it's being traced - otherwise breakpoints set in it may interfere
706 * with another untraced process
707 */
708 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
709 vm_flags &= ~VM_MAYSHARE;
710
711 return vm_flags;
712}
713
714/*
715 * set up a shared mapping on a file
716 */
717static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
718{
719 int ret;
720
721 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
722 if (ret != -ENOSYS)
723 return ret;
724
725 /* getting an ENOSYS error indicates that direct mmap isn't
726 * possible (as opposed to tried but failed) so we'll fall
727 * through to making a private copy of the data and mapping
728 * that if we can */
729 return -ENODEV;
730}
731
732/*
733 * set up a private mapping or an anonymous shared mapping
734 */
735static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
736{
737 void *base;
738 int ret;
739
740 /* invoke the file's mapping function so that it can keep track of
741 * shared mappings on devices or memory
742 * - VM_MAYSHARE will be set if it may attempt to share
743 */
744 if (vma->vm_file) {
745 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
746 if (ret != -ENOSYS) {
747 /* shouldn't return success if we're not sharing */
748 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
749 return ret; /* success or a real error */
750 }
751
752 /* getting an ENOSYS error indicates that direct mmap isn't
753 * possible (as opposed to tried but failed) so we'll try to
754 * make a private copy of the data and map that instead */
755 }
756
757 /* allocate some memory to hold the mapping
758 * - note that this may not return a page-aligned address if the object
759 * we're allocating is smaller than a page
760 */
Nick Piggin84097512006-03-22 00:08:34 -0800761 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 if (!base)
763 goto enomem;
764
765 vma->vm_start = (unsigned long) base;
766 vma->vm_end = vma->vm_start + len;
767 vma->vm_flags |= VM_MAPPED_COPY;
768
769#ifdef WARN_ON_SLACK
770 if (len + WARN_ON_SLACK <= kobjsize(result))
771 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
772 len, current->pid, kobjsize(result) - len);
773#endif
774
775 if (vma->vm_file) {
776 /* read the contents of a file into the copy */
777 mm_segment_t old_fs;
778 loff_t fpos;
779
780 fpos = vma->vm_pgoff;
781 fpos <<= PAGE_SHIFT;
782
783 old_fs = get_fs();
784 set_fs(KERNEL_DS);
785 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
786 set_fs(old_fs);
787
788 if (ret < 0)
789 goto error_free;
790
791 /* clear the last little bit */
792 if (ret < len)
793 memset(base + ret, 0, len - ret);
794
795 } else {
796 /* if it's an anonymous mapping, then just clear it */
797 memset(base, 0, len);
798 }
799
800 return 0;
801
802error_free:
803 kfree(base);
804 vma->vm_start = 0;
805 return ret;
806
807enomem:
808 printk("Allocation of length %lu from process %d failed\n",
809 len, current->pid);
810 show_free_areas();
811 return -ENOMEM;
812}
813
814/*
815 * handle mapping creation for uClinux
816 */
817unsigned long do_mmap_pgoff(struct file *file,
818 unsigned long addr,
819 unsigned long len,
820 unsigned long prot,
821 unsigned long flags,
822 unsigned long pgoff)
823{
824 struct vm_list_struct *vml = NULL;
825 struct vm_area_struct *vma = NULL;
826 struct rb_node *rb;
827 unsigned long capabilities, vm_flags;
828 void *result;
829 int ret;
830
831 /* decide whether we should attempt the mapping, and if so what sort of
832 * mapping */
833 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
834 &capabilities);
835 if (ret < 0)
836 return ret;
837
838 /* we've determined that we can make the mapping, now translate what we
839 * now know into VMA flags */
840 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
841
842 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800843 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 if (!vml)
845 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
847 down_write(&nommu_vma_sem);
848
849 /* if we want to share, we need to check for VMAs created by other
850 * mmap() calls that overlap with our proposed mapping
851 * - we can only share with an exact match on most regular files
852 * - shared mappings on character devices and memory backed files are
853 * permitted to overlap inexactly as far as we are concerned for in
854 * these cases, sharing is handled in the driver or filesystem rather
855 * than here
856 */
857 if (vm_flags & VM_MAYSHARE) {
858 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
859 unsigned long vmpglen;
860
David Howells165b2392007-03-22 00:11:24 -0800861 /* suppress VMA sharing for shared regions */
862 if (vm_flags & VM_SHARED &&
863 capabilities & BDI_CAP_MAP_DIRECT)
864 goto dont_share_VMAs;
865
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
867 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
868
869 if (!(vma->vm_flags & VM_MAYSHARE))
870 continue;
871
872 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800873 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 continue;
875
876 if (vma->vm_pgoff >= pgoff + pglen)
877 continue;
878
879 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
880 vmpglen >>= PAGE_SHIFT;
881 if (pgoff >= vma->vm_pgoff + vmpglen)
882 continue;
883
884 /* handle inexactly overlapping matches between mappings */
885 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
886 if (!(capabilities & BDI_CAP_MAP_DIRECT))
887 goto sharing_violation;
888 continue;
889 }
890
891 /* we've found a VMA we can share */
892 atomic_inc(&vma->vm_usage);
893
894 vml->vma = vma;
895 result = (void *) vma->vm_start;
896 goto shared;
897 }
898
David Howells165b2392007-03-22 00:11:24 -0800899 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 vma = NULL;
901
902 /* obtain the address at which to make a shared mapping
903 * - this is the hook for quasi-memory character devices to
904 * tell us the location of a shared mapping
905 */
906 if (file && file->f_op->get_unmapped_area) {
907 addr = file->f_op->get_unmapped_area(file, addr, len,
908 pgoff, flags);
909 if (IS_ERR((void *) addr)) {
910 ret = addr;
911 if (ret != (unsigned long) -ENOSYS)
912 goto error;
913
914 /* the driver refused to tell us where to site
915 * the mapping so we'll have to attempt to copy
916 * it */
917 ret = (unsigned long) -ENODEV;
918 if (!(capabilities & BDI_CAP_MAP_COPY))
919 goto error;
920
921 capabilities &= ~BDI_CAP_MAP_DIRECT;
922 }
923 }
924 }
925
926 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800927 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 if (!vma)
929 goto error_getting_vma;
930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 INIT_LIST_HEAD(&vma->anon_vma_node);
932 atomic_set(&vma->vm_usage, 1);
933 if (file)
934 get_file(file);
935 vma->vm_file = file;
936 vma->vm_flags = vm_flags;
937 vma->vm_start = addr;
938 vma->vm_end = addr + len;
939 vma->vm_pgoff = pgoff;
940
941 vml->vma = vma;
942
943 /* set up the mapping */
944 if (file && vma->vm_flags & VM_SHARED)
945 ret = do_mmap_shared_file(vma, len);
946 else
947 ret = do_mmap_private(vma, len);
948 if (ret < 0)
949 goto error;
950
951 /* okay... we have a mapping; now we have to register it */
952 result = (void *) vma->vm_start;
953
954 if (vma->vm_flags & VM_MAPPED_COPY) {
955 realalloc += kobjsize(result);
956 askedalloc += len;
957 }
958
959 realalloc += kobjsize(vma);
960 askedalloc += sizeof(*vma);
961
962 current->mm->total_vm += len >> PAGE_SHIFT;
963
964 add_nommu_vma(vma);
965
966 shared:
967 realalloc += kobjsize(vml);
968 askedalloc += sizeof(*vml);
969
David Howells30340972006-09-27 01:50:20 -0700970 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971
972 up_write(&nommu_vma_sem);
973
974 if (prot & PROT_EXEC)
975 flush_icache_range((unsigned long) result,
976 (unsigned long) result + len);
977
978#ifdef DEBUG
979 printk("do_mmap:\n");
980 show_process_blocks();
981#endif
982
983 return (unsigned long) result;
984
985 error:
986 up_write(&nommu_vma_sem);
987 kfree(vml);
988 if (vma) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -0700989 if (vma->vm_file)
990 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 kfree(vma);
992 }
993 return ret;
994
995 sharing_violation:
996 up_write(&nommu_vma_sem);
997 printk("Attempt to share mismatched mappings\n");
998 kfree(vml);
999 return -EINVAL;
1000
1001 error_getting_vma:
1002 up_write(&nommu_vma_sem);
1003 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001004 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 len, current->pid);
1006 show_free_areas();
1007 return -ENOMEM;
1008
1009 error_getting_vml:
1010 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1011 len, current->pid);
1012 show_free_areas();
1013 return -ENOMEM;
1014}
Paul Mundtb5073172007-07-21 04:37:25 -07001015EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016
1017/*
1018 * handle mapping disposal for uClinux
1019 */
1020static void put_vma(struct vm_area_struct *vma)
1021{
1022 if (vma) {
1023 down_write(&nommu_vma_sem);
1024
1025 if (atomic_dec_and_test(&vma->vm_usage)) {
1026 delete_nommu_vma(vma);
1027
1028 if (vma->vm_ops && vma->vm_ops->close)
1029 vma->vm_ops->close(vma);
1030
1031 /* IO memory and memory shared directly out of the pagecache from
1032 * ramfs/tmpfs mustn't be released here */
1033 if (vma->vm_flags & VM_MAPPED_COPY) {
1034 realalloc -= kobjsize((void *) vma->vm_start);
1035 askedalloc -= vma->vm_end - vma->vm_start;
1036 kfree((void *) vma->vm_start);
1037 }
1038
1039 realalloc -= kobjsize(vma);
1040 askedalloc -= sizeof(*vma);
1041
1042 if (vma->vm_file)
1043 fput(vma->vm_file);
1044 kfree(vma);
1045 }
1046
1047 up_write(&nommu_vma_sem);
1048 }
1049}
1050
David Howells30340972006-09-27 01:50:20 -07001051/*
1052 * release a mapping
1053 * - under NOMMU conditions the parameters must match exactly to the mapping to
1054 * be removed
1055 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1057{
1058 struct vm_list_struct *vml, **parent;
1059 unsigned long end = addr + len;
1060
1061#ifdef DEBUG
1062 printk("do_munmap:\n");
1063#endif
1064
David Howells30340972006-09-27 01:50:20 -07001065 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1066 if ((*parent)->vma->vm_start > addr)
1067 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001069 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 goto found;
David Howells30340972006-09-27 01:50:20 -07001071 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072
1073 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1074 current->pid, current->comm, (void *) addr);
1075 return -EINVAL;
1076
1077 found:
1078 vml = *parent;
1079
1080 put_vma(vml->vma);
1081
1082 *parent = vml->next;
1083 realalloc -= kobjsize(vml);
1084 askedalloc -= sizeof(*vml);
1085 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001086
1087 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 mm->total_vm -= len >> PAGE_SHIFT;
1089
1090#ifdef DEBUG
1091 show_process_blocks();
1092#endif
1093
1094 return 0;
1095}
Paul Mundtb5073172007-07-21 04:37:25 -07001096EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097
David Howells30340972006-09-27 01:50:20 -07001098asmlinkage long sys_munmap(unsigned long addr, size_t len)
1099{
1100 int ret;
1101 struct mm_struct *mm = current->mm;
1102
1103 down_write(&mm->mmap_sem);
1104 ret = do_munmap(mm, addr, len);
1105 up_write(&mm->mmap_sem);
1106 return ret;
1107}
1108
1109/*
1110 * Release all mappings
1111 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112void exit_mmap(struct mm_struct * mm)
1113{
1114 struct vm_list_struct *tmp;
1115
1116 if (mm) {
1117#ifdef DEBUG
1118 printk("Exit_mmap:\n");
1119#endif
1120
1121 mm->total_vm = 0;
1122
1123 while ((tmp = mm->context.vmlist)) {
1124 mm->context.vmlist = tmp->next;
1125 put_vma(tmp->vma);
1126
1127 realalloc -= kobjsize(tmp);
1128 askedalloc -= sizeof(*tmp);
1129 kfree(tmp);
1130 }
1131
1132#ifdef DEBUG
1133 show_process_blocks();
1134#endif
1135 }
1136}
1137
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138unsigned long do_brk(unsigned long addr, unsigned long len)
1139{
1140 return -ENOMEM;
1141}
1142
1143/*
David Howells6fa5f802006-09-27 01:50:21 -07001144 * expand (or shrink) an existing mapping, potentially moving it at the same
1145 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 *
David Howells6fa5f802006-09-27 01:50:21 -07001147 * under NOMMU conditions, we only permit changing a mapping's size, and only
1148 * as long as it stays within the hole allocated by the kmalloc() call in
1149 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 *
David Howells6fa5f802006-09-27 01:50:21 -07001151 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 */
1153unsigned long do_mremap(unsigned long addr,
1154 unsigned long old_len, unsigned long new_len,
1155 unsigned long flags, unsigned long new_addr)
1156{
David Howells6fa5f802006-09-27 01:50:21 -07001157 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158
1159 /* insanity checks first */
1160 if (new_len == 0)
1161 return (unsigned long) -EINVAL;
1162
1163 if (flags & MREMAP_FIXED && new_addr != addr)
1164 return (unsigned long) -EINVAL;
1165
David Howells6fa5f802006-09-27 01:50:21 -07001166 vma = find_vma_exact(current->mm, addr);
1167 if (!vma)
1168 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169
David Howells6fa5f802006-09-27 01:50:21 -07001170 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 return (unsigned long) -EFAULT;
1172
David Howells6fa5f802006-09-27 01:50:21 -07001173 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 return (unsigned long) -EPERM;
1175
1176 if (new_len > kobjsize((void *) addr))
1177 return (unsigned long) -ENOMEM;
1178
1179 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001180 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181
1182 askedalloc -= old_len;
1183 askedalloc += new_len;
1184
David Howells6fa5f802006-09-27 01:50:21 -07001185 return vma->vm_start;
1186}
Paul Mundtb5073172007-07-21 04:37:25 -07001187EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001188
1189asmlinkage unsigned long sys_mremap(unsigned long addr,
1190 unsigned long old_len, unsigned long new_len,
1191 unsigned long flags, unsigned long new_addr)
1192{
1193 unsigned long ret;
1194
1195 down_write(&current->mm->mmap_sem);
1196 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1197 up_write(&current->mm->mmap_sem);
1198 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199}
1200
Linus Torvalds6aab3412005-11-28 14:34:23 -08001201struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001202 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203{
1204 return NULL;
1205}
1206
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1208 unsigned long to, unsigned long size, pgprot_t prot)
1209{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001210 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1211 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212}
Luke Yang22c4af42006-07-14 00:24:09 -07001213EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214
1215void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1216{
1217}
1218
1219unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1220 unsigned long len, unsigned long pgoff, unsigned long flags)
1221{
1222 return -ENOMEM;
1223}
1224
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001225void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226{
1227}
1228
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229void unmap_mapping_range(struct address_space *mapping,
1230 loff_t const holebegin, loff_t const holelen,
1231 int even_cows)
1232{
1233}
Luke Yang22c4af42006-07-14 00:24:09 -07001234EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235
1236/*
David Howellsd56e03c2007-03-22 00:11:23 -08001237 * ask for an unmapped area at which to create a mapping on a file
1238 */
1239unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1240 unsigned long len, unsigned long pgoff,
1241 unsigned long flags)
1242{
1243 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1244 unsigned long, unsigned long);
1245
1246 get_area = current->mm->get_unmapped_area;
1247 if (file && file->f_op && file->f_op->get_unmapped_area)
1248 get_area = file->f_op->get_unmapped_area;
1249
1250 if (!get_area)
1251 return -ENOSYS;
1252
1253 return get_area(file, addr, len, pgoff, flags);
1254}
David Howellsd56e03c2007-03-22 00:11:23 -08001255EXPORT_SYMBOL(get_unmapped_area);
1256
1257/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 * Check that a process has enough memory to allocate a new virtual
1259 * mapping. 0 means there is enough memory for the allocation to
1260 * succeed and -ENOMEM implies there is not.
1261 *
1262 * We currently support three overcommit policies, which are set via the
1263 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1264 *
1265 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1266 * Additional code 2002 Jul 20 by Robert Love.
1267 *
1268 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1269 *
1270 * Note this is a helper function intended to be used by LSMs which
1271 * wish to use this logic.
1272 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001273int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274{
1275 unsigned long free, allowed;
1276
1277 vm_acct_memory(pages);
1278
1279 /*
1280 * Sometimes we want to use more memory than we have
1281 */
1282 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1283 return 0;
1284
1285 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1286 unsigned long n;
1287
Christoph Lameter347ce432006-06-30 01:55:35 -07001288 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 free += nr_swap_pages;
1290
1291 /*
1292 * Any slabs which are created with the
1293 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1294 * which are reclaimable, under pressure. The dentry
1295 * cache and most inode caches should fall into this
1296 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001297 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298
1299 /*
1300 * Leave the last 3% for root
1301 */
1302 if (!cap_sys_admin)
1303 free -= free / 32;
1304
1305 if (free > pages)
1306 return 0;
1307
1308 /*
1309 * nr_free_pages() is very expensive on large systems,
1310 * only call if we're about to fail.
1311 */
1312 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001313
1314 /*
1315 * Leave reserved pages. The pages are not for anonymous pages.
1316 */
1317 if (n <= totalreserve_pages)
1318 goto error;
1319 else
1320 n -= totalreserve_pages;
1321
1322 /*
1323 * Leave the last 3% for root
1324 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 if (!cap_sys_admin)
1326 n -= n / 32;
1327 free += n;
1328
1329 if (free > pages)
1330 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001331
1332 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 }
1334
1335 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1336 /*
1337 * Leave the last 3% for root
1338 */
1339 if (!cap_sys_admin)
1340 allowed -= allowed / 32;
1341 allowed += total_swap_pages;
1342
1343 /* Don't let a single process grow too big:
1344 leave 3% of the size of this process for other processes */
1345 allowed -= current->mm->total_vm / 32;
1346
Simon Derr2f60f8d2005-08-04 19:52:03 -07001347 /*
1348 * cast `allowed' as a signed long because vm_committed_space
1349 * sometimes has a negative value
1350 */
1351 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001353error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 vm_unacct_memory(pages);
1355
1356 return -ENOMEM;
1357}
1358
1359int in_gate_area_no_task(unsigned long addr)
1360{
1361 return 0;
1362}
David Howellsb0e15192006-01-06 00:11:42 -08001363
Nick Piggind0217ac2007-07-19 01:47:03 -07001364int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001365{
1366 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001367 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001368}
Paul Mundtb5073172007-07-21 04:37:25 -07001369EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001370
1371/*
1372 * Access another process' address space.
1373 * - source/target buffer must be kernel space
1374 */
1375int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1376{
David Howells0ec76a12006-09-27 01:50:15 -07001377 struct vm_area_struct *vma;
1378 struct mm_struct *mm;
1379
1380 if (addr + len < addr)
1381 return 0;
1382
1383 mm = get_task_mm(tsk);
1384 if (!mm)
1385 return 0;
1386
1387 down_read(&mm->mmap_sem);
1388
1389 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001390 vma = find_vma(mm, addr);
1391 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001392 /* don't overrun this mapping */
1393 if (addr + len >= vma->vm_end)
1394 len = vma->vm_end - addr;
1395
1396 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07001397 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001398 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07001399 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001400 len -= copy_from_user(buf, (void *) addr, len);
1401 else
1402 len = 0;
1403 } else {
1404 len = 0;
1405 }
1406
1407 up_read(&mm->mmap_sem);
1408 mmput(mm);
1409 return len;
1410}