blob: b989cb928a7cf29ec5ad66ff519f80633bfe8129 [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
David Howellsf2b85442007-10-29 13:15:39 +000015#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/mm.h>
17#include <linux/mman.h>
18#include <linux/swap.h>
19#include <linux/file.h>
20#include <linux/highmem.h>
21#include <linux/pagemap.h>
22#include <linux/slab.h>
23#include <linux/vmalloc.h>
24#include <linux/ptrace.h>
25#include <linux/blkdev.h>
26#include <linux/backing-dev.h>
27#include <linux/mount.h>
28#include <linux/personality.h>
29#include <linux/security.h>
30#include <linux/syscalls.h>
31
32#include <asm/uaccess.h>
33#include <asm/tlb.h>
34#include <asm/tlbflush.h>
35
36void *high_memory;
37struct page *mem_map;
38unsigned long max_mapnr;
39unsigned long num_physpages;
40unsigned long askedalloc, realalloc;
41atomic_t vm_committed_space = ATOMIC_INIT(0);
42int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
43int sysctl_overcommit_ratio = 50; /* default is 50% */
44int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
45int heap_stack_gap = 0;
46
47EXPORT_SYMBOL(mem_map);
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 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200179 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
180 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 */
Nick Piggin84097512006-03-22 00:08:34 -0800182 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183}
Paul Mundtb5073172007-07-21 04:37:25 -0700184EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
186struct page * vmalloc_to_page(void *addr)
187{
188 return virt_to_page(addr);
189}
Paul Mundtb5073172007-07-21 04:37:25 -0700190EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
192unsigned long vmalloc_to_pfn(void *addr)
193{
194 return page_to_pfn(virt_to_page(addr));
195}
Paul Mundtb5073172007-07-21 04:37:25 -0700196EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
198long vread(char *buf, char *addr, unsigned long count)
199{
200 memcpy(buf, addr, count);
201 return count;
202}
203
204long vwrite(char *buf, char *addr, unsigned long count)
205{
206 /* Don't allow overflow */
207 if ((unsigned long) addr + count < count)
208 count = -(unsigned long) addr;
209
210 memcpy(addr, buf, count);
211 return(count);
212}
213
214/*
215 * vmalloc - allocate virtually continguos memory
216 *
217 * @size: allocation size
218 *
219 * Allocate enough pages to cover @size from the page level
220 * allocator and map them into continguos kernel virtual space.
221 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200222 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 * use __vmalloc() instead.
224 */
225void *vmalloc(unsigned long size)
226{
227 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
228}
Andrew Mortonf6138882006-02-28 16:59:18 -0800229EXPORT_SYMBOL(vmalloc);
230
231void *vmalloc_node(unsigned long size, int node)
232{
233 return vmalloc(size);
234}
235EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Paul Mundtb5073172007-07-21 04:37:25 -0700237/**
238 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 * @size: allocation size
240 *
241 * Allocate enough 32bit PA addressable pages to cover @size from the
242 * page level allocator and map them into continguos kernel virtual space.
243 */
244void *vmalloc_32(unsigned long size)
245{
246 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
247}
Paul Mundtb5073172007-07-21 04:37:25 -0700248EXPORT_SYMBOL(vmalloc_32);
249
250/**
251 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
252 * @size: allocation size
253 *
254 * The resulting memory area is 32bit addressable and zeroed so it can be
255 * mapped to userspace without leaking data.
256 */
257void *vmalloc_32_user(unsigned long size)
258{
259 return __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
260}
261EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
264{
265 BUG();
266 return NULL;
267}
Paul Mundtb5073172007-07-21 04:37:25 -0700268EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
270void vunmap(void *addr)
271{
272 BUG();
273}
Paul Mundtb5073172007-07-21 04:37:25 -0700274EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
276/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700277 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
278 * have one.
279 */
280void __attribute__((weak)) vmalloc_sync_all(void)
281{
282}
283
Paul Mundtb5073172007-07-21 04:37:25 -0700284int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
285 struct page *page)
286{
287 return -EINVAL;
288}
289EXPORT_SYMBOL(vm_insert_page);
290
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700291/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 * sys_brk() for the most part doesn't need the global kernel
293 * lock, except when an application is doing something nasty
294 * like trying to un-brk an area that has already been mapped
295 * to a regular file. in this case, the unmapping will need
296 * to invoke file system routines that need the global lock.
297 */
298asmlinkage unsigned long sys_brk(unsigned long brk)
299{
300 struct mm_struct *mm = current->mm;
301
302 if (brk < mm->start_brk || brk > mm->context.end_brk)
303 return mm->brk;
304
305 if (mm->brk == brk)
306 return mm->brk;
307
308 /*
309 * Always allow shrinking brk
310 */
311 if (brk <= mm->brk) {
312 mm->brk = brk;
313 return brk;
314 }
315
316 /*
317 * Ok, looks good - let it rip.
318 */
319 return mm->brk = brk;
320}
321
322#ifdef DEBUG
323static void show_process_blocks(void)
324{
325 struct vm_list_struct *vml;
326
327 printk("Process blocks %d:", current->pid);
328
329 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
330 printk(" %p: %p", vml, vml->vma);
331 if (vml->vma)
332 printk(" (%d @%lx #%d)",
333 kobjsize((void *) vml->vma->vm_start),
334 vml->vma->vm_start,
335 atomic_read(&vml->vma->vm_usage));
336 printk(vml->next ? " ->" : ".\n");
337 }
338}
339#endif /* DEBUG */
340
David Howells30340972006-09-27 01:50:20 -0700341/*
342 * add a VMA into a process's mm_struct in the appropriate place in the list
343 * - should be called with mm->mmap_sem held writelocked
344 */
345static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
346{
347 struct vm_list_struct **ppv;
348
349 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
350 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
351 break;
352
353 vml->next = *ppv;
354 *ppv = vml;
355}
356
357/*
358 * look up the first VMA in which addr resides, NULL if none
359 * - should be called with mm->mmap_sem at least held readlocked
360 */
361struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
362{
363 struct vm_list_struct *loop, *vml;
364
365 /* search the vm_start ordered list */
366 vml = NULL;
367 for (loop = mm->context.vmlist; loop; loop = loop->next) {
368 if (loop->vma->vm_start > addr)
369 break;
370 vml = loop;
371 }
372
373 if (vml && vml->vma->vm_end > addr)
374 return vml->vma;
375
376 return NULL;
377}
378EXPORT_SYMBOL(find_vma);
379
380/*
David Howells930e6522006-09-27 01:50:22 -0700381 * find a VMA
382 * - we don't extend stack VMAs under NOMMU conditions
383 */
384struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
385{
386 return find_vma(mm, addr);
387}
388
Greg Ungerer57c8f632007-07-15 23:38:28 -0700389int expand_stack(struct vm_area_struct *vma, unsigned long address)
390{
391 return -ENOMEM;
392}
393
David Howells930e6522006-09-27 01:50:22 -0700394/*
David Howells6fa5f802006-09-27 01:50:21 -0700395 * look up the first VMA exactly that exactly matches addr
396 * - should be called with mm->mmap_sem at least held readlocked
397 */
398static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
399 unsigned long addr)
400{
401 struct vm_list_struct *vml;
402
403 /* search the vm_start ordered list */
404 for (vml = mm->context.vmlist; vml; vml = vml->next) {
405 if (vml->vma->vm_start == addr)
406 return vml->vma;
407 if (vml->vma->vm_start > addr)
408 break;
409 }
410
411 return NULL;
412}
413
414/*
David Howells30340972006-09-27 01:50:20 -0700415 * find a VMA in the global tree
416 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
418{
419 struct vm_area_struct *vma;
420 struct rb_node *n = nommu_vma_tree.rb_node;
421
422 while (n) {
423 vma = rb_entry(n, struct vm_area_struct, vm_rb);
424
425 if (start < vma->vm_start)
426 n = n->rb_left;
427 else if (start > vma->vm_start)
428 n = n->rb_right;
429 else
430 return vma;
431 }
432
433 return NULL;
434}
435
David Howells30340972006-09-27 01:50:20 -0700436/*
437 * add a VMA in the global tree
438 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439static void add_nommu_vma(struct vm_area_struct *vma)
440{
441 struct vm_area_struct *pvma;
442 struct address_space *mapping;
443 struct rb_node **p = &nommu_vma_tree.rb_node;
444 struct rb_node *parent = NULL;
445
446 /* add the VMA to the mapping */
447 if (vma->vm_file) {
448 mapping = vma->vm_file->f_mapping;
449
450 flush_dcache_mmap_lock(mapping);
451 vma_prio_tree_insert(vma, &mapping->i_mmap);
452 flush_dcache_mmap_unlock(mapping);
453 }
454
455 /* add the VMA to the master list */
456 while (*p) {
457 parent = *p;
458 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
459
460 if (vma->vm_start < pvma->vm_start) {
461 p = &(*p)->rb_left;
462 }
463 else if (vma->vm_start > pvma->vm_start) {
464 p = &(*p)->rb_right;
465 }
466 else {
467 /* mappings are at the same address - this can only
468 * happen for shared-mem chardevs and shared file
469 * mappings backed by ramfs/tmpfs */
470 BUG_ON(!(pvma->vm_flags & VM_SHARED));
471
472 if (vma < pvma)
473 p = &(*p)->rb_left;
474 else if (vma > pvma)
475 p = &(*p)->rb_right;
476 else
477 BUG();
478 }
479 }
480
481 rb_link_node(&vma->vm_rb, parent, p);
482 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
483}
484
David Howells30340972006-09-27 01:50:20 -0700485/*
486 * delete a VMA from the global list
487 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488static void delete_nommu_vma(struct vm_area_struct *vma)
489{
490 struct address_space *mapping;
491
492 /* remove the VMA from the mapping */
493 if (vma->vm_file) {
494 mapping = vma->vm_file->f_mapping;
495
496 flush_dcache_mmap_lock(mapping);
497 vma_prio_tree_remove(vma, &mapping->i_mmap);
498 flush_dcache_mmap_unlock(mapping);
499 }
500
501 /* remove from the master list */
502 rb_erase(&vma->vm_rb, &nommu_vma_tree);
503}
504
505/*
506 * determine whether a mapping should be permitted and, if so, what sort of
507 * mapping we're capable of supporting
508 */
509static int validate_mmap_request(struct file *file,
510 unsigned long addr,
511 unsigned long len,
512 unsigned long prot,
513 unsigned long flags,
514 unsigned long pgoff,
515 unsigned long *_capabilities)
516{
517 unsigned long capabilities;
518 unsigned long reqprot = prot;
519 int ret;
520
521 /* do the simple checks first */
522 if (flags & MAP_FIXED || addr) {
523 printk(KERN_DEBUG
524 "%d: Can't do fixed-address/overlay mmap of RAM\n",
525 current->pid);
526 return -EINVAL;
527 }
528
529 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
530 (flags & MAP_TYPE) != MAP_SHARED)
531 return -EINVAL;
532
Mike Frysingerf81cff02006-12-06 12:02:59 +1000533 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 return -EINVAL;
535
Mike Frysingerf81cff02006-12-06 12:02:59 +1000536 /* Careful about overflows.. */
537 len = PAGE_ALIGN(len);
538 if (!len || len > TASK_SIZE)
539 return -ENOMEM;
540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 /* offset overflow? */
542 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000543 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544
545 if (file) {
546 /* validate file mapping requests */
547 struct address_space *mapping;
548
549 /* files must support mmap */
550 if (!file->f_op || !file->f_op->mmap)
551 return -ENODEV;
552
553 /* work out if what we've got could possibly be shared
554 * - we support chardevs that provide their own "memory"
555 * - we support files/blockdevs that are memory backed
556 */
557 mapping = file->f_mapping;
558 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800559 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560
561 capabilities = 0;
562 if (mapping && mapping->backing_dev_info)
563 capabilities = mapping->backing_dev_info->capabilities;
564
565 if (!capabilities) {
566 /* no explicit capabilities set, so assume some
567 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800568 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 case S_IFREG:
570 case S_IFBLK:
571 capabilities = BDI_CAP_MAP_COPY;
572 break;
573
574 case S_IFCHR:
575 capabilities =
576 BDI_CAP_MAP_DIRECT |
577 BDI_CAP_READ_MAP |
578 BDI_CAP_WRITE_MAP;
579 break;
580
581 default:
582 return -EINVAL;
583 }
584 }
585
586 /* eliminate any capabilities that we can't support on this
587 * device */
588 if (!file->f_op->get_unmapped_area)
589 capabilities &= ~BDI_CAP_MAP_DIRECT;
590 if (!file->f_op->read)
591 capabilities &= ~BDI_CAP_MAP_COPY;
592
593 if (flags & MAP_SHARED) {
594 /* do checks for writing, appending and locking */
595 if ((prot & PROT_WRITE) &&
596 !(file->f_mode & FMODE_WRITE))
597 return -EACCES;
598
Josef Sipeke9536ae2006-12-08 02:37:21 -0800599 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 (file->f_mode & FMODE_WRITE))
601 return -EACCES;
602
Josef Sipeke9536ae2006-12-08 02:37:21 -0800603 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 return -EAGAIN;
605
606 if (!(capabilities & BDI_CAP_MAP_DIRECT))
607 return -ENODEV;
608
609 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
610 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
611 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
612 ) {
613 printk("MAP_SHARED not completely supported on !MMU\n");
614 return -EINVAL;
615 }
616
617 /* we mustn't privatise shared mappings */
618 capabilities &= ~BDI_CAP_MAP_COPY;
619 }
620 else {
621 /* we're going to read the file into private memory we
622 * allocate */
623 if (!(capabilities & BDI_CAP_MAP_COPY))
624 return -ENODEV;
625
626 /* we don't permit a private writable mapping to be
627 * shared with the backing device */
628 if (prot & PROT_WRITE)
629 capabilities &= ~BDI_CAP_MAP_DIRECT;
630 }
631
632 /* handle executable mappings and implied executable
633 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800634 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 if (prot & PROT_EXEC)
636 return -EPERM;
637 }
638 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
639 /* handle implication of PROT_EXEC by PROT_READ */
640 if (current->personality & READ_IMPLIES_EXEC) {
641 if (capabilities & BDI_CAP_EXEC_MAP)
642 prot |= PROT_EXEC;
643 }
644 }
645 else if ((prot & PROT_READ) &&
646 (prot & PROT_EXEC) &&
647 !(capabilities & BDI_CAP_EXEC_MAP)
648 ) {
649 /* backing file is not executable, try to copy */
650 capabilities &= ~BDI_CAP_MAP_DIRECT;
651 }
652 }
653 else {
654 /* anonymous mappings are always memory backed and can be
655 * privately mapped
656 */
657 capabilities = BDI_CAP_MAP_COPY;
658
659 /* handle PROT_EXEC implication by PROT_READ */
660 if ((prot & PROT_READ) &&
661 (current->personality & READ_IMPLIES_EXEC))
662 prot |= PROT_EXEC;
663 }
664
665 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400666 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 if (ret < 0)
668 return ret;
669
670 /* looks okay */
671 *_capabilities = capabilities;
672 return 0;
673}
674
675/*
676 * we've determined that we can make the mapping, now translate what we
677 * now know into VMA flags
678 */
679static unsigned long determine_vm_flags(struct file *file,
680 unsigned long prot,
681 unsigned long flags,
682 unsigned long capabilities)
683{
684 unsigned long vm_flags;
685
686 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
687 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
688 /* vm_flags |= mm->def_flags; */
689
690 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
691 /* attempt to share read-only copies of mapped file chunks */
692 if (file && !(prot & PROT_WRITE))
693 vm_flags |= VM_MAYSHARE;
694 }
695 else {
696 /* overlay a shareable mapping on the backing device or inode
697 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
698 * romfs/cramfs */
699 if (flags & MAP_SHARED)
700 vm_flags |= VM_MAYSHARE | VM_SHARED;
701 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
702 vm_flags |= VM_MAYSHARE;
703 }
704
705 /* refuse to let anyone share private mappings with this process if
706 * it's being traced - otherwise breakpoints set in it may interfere
707 * with another untraced process
708 */
709 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
710 vm_flags &= ~VM_MAYSHARE;
711
712 return vm_flags;
713}
714
715/*
716 * set up a shared mapping on a file
717 */
718static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
719{
720 int ret;
721
722 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
723 if (ret != -ENOSYS)
724 return ret;
725
726 /* getting an ENOSYS error indicates that direct mmap isn't
727 * possible (as opposed to tried but failed) so we'll fall
728 * through to making a private copy of the data and mapping
729 * that if we can */
730 return -ENODEV;
731}
732
733/*
734 * set up a private mapping or an anonymous shared mapping
735 */
736static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
737{
738 void *base;
739 int ret;
740
741 /* invoke the file's mapping function so that it can keep track of
742 * shared mappings on devices or memory
743 * - VM_MAYSHARE will be set if it may attempt to share
744 */
745 if (vma->vm_file) {
746 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
747 if (ret != -ENOSYS) {
748 /* shouldn't return success if we're not sharing */
749 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
750 return ret; /* success or a real error */
751 }
752
753 /* getting an ENOSYS error indicates that direct mmap isn't
754 * possible (as opposed to tried but failed) so we'll try to
755 * make a private copy of the data and map that instead */
756 }
757
758 /* allocate some memory to hold the mapping
759 * - note that this may not return a page-aligned address if the object
760 * we're allocating is smaller than a page
761 */
Nick Piggin84097512006-03-22 00:08:34 -0800762 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 if (!base)
764 goto enomem;
765
766 vma->vm_start = (unsigned long) base;
767 vma->vm_end = vma->vm_start + len;
768 vma->vm_flags |= VM_MAPPED_COPY;
769
770#ifdef WARN_ON_SLACK
771 if (len + WARN_ON_SLACK <= kobjsize(result))
772 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
773 len, current->pid, kobjsize(result) - len);
774#endif
775
776 if (vma->vm_file) {
777 /* read the contents of a file into the copy */
778 mm_segment_t old_fs;
779 loff_t fpos;
780
781 fpos = vma->vm_pgoff;
782 fpos <<= PAGE_SHIFT;
783
784 old_fs = get_fs();
785 set_fs(KERNEL_DS);
786 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
787 set_fs(old_fs);
788
789 if (ret < 0)
790 goto error_free;
791
792 /* clear the last little bit */
793 if (ret < len)
794 memset(base + ret, 0, len - ret);
795
796 } else {
797 /* if it's an anonymous mapping, then just clear it */
798 memset(base, 0, len);
799 }
800
801 return 0;
802
803error_free:
804 kfree(base);
805 vma->vm_start = 0;
806 return ret;
807
808enomem:
809 printk("Allocation of length %lu from process %d failed\n",
810 len, current->pid);
811 show_free_areas();
812 return -ENOMEM;
813}
814
815/*
816 * handle mapping creation for uClinux
817 */
818unsigned long do_mmap_pgoff(struct file *file,
819 unsigned long addr,
820 unsigned long len,
821 unsigned long prot,
822 unsigned long flags,
823 unsigned long pgoff)
824{
825 struct vm_list_struct *vml = NULL;
826 struct vm_area_struct *vma = NULL;
827 struct rb_node *rb;
828 unsigned long capabilities, vm_flags;
829 void *result;
830 int ret;
831
Eric Paris7cd94142007-11-26 18:47:40 -0500832 if (!(flags & MAP_FIXED))
833 addr = round_hint_to_min(addr);
834
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 /* decide whether we should attempt the mapping, and if so what sort of
836 * mapping */
837 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
838 &capabilities);
839 if (ret < 0)
840 return ret;
841
842 /* we've determined that we can make the mapping, now translate what we
843 * now know into VMA flags */
844 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
845
846 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800847 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 if (!vml)
849 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
851 down_write(&nommu_vma_sem);
852
853 /* if we want to share, we need to check for VMAs created by other
854 * mmap() calls that overlap with our proposed mapping
855 * - we can only share with an exact match on most regular files
856 * - shared mappings on character devices and memory backed files are
857 * permitted to overlap inexactly as far as we are concerned for in
858 * these cases, sharing is handled in the driver or filesystem rather
859 * than here
860 */
861 if (vm_flags & VM_MAYSHARE) {
862 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
863 unsigned long vmpglen;
864
David Howells165b2392007-03-22 00:11:24 -0800865 /* suppress VMA sharing for shared regions */
866 if (vm_flags & VM_SHARED &&
867 capabilities & BDI_CAP_MAP_DIRECT)
868 goto dont_share_VMAs;
869
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
871 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
872
873 if (!(vma->vm_flags & VM_MAYSHARE))
874 continue;
875
876 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800877 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 continue;
879
880 if (vma->vm_pgoff >= pgoff + pglen)
881 continue;
882
883 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
884 vmpglen >>= PAGE_SHIFT;
885 if (pgoff >= vma->vm_pgoff + vmpglen)
886 continue;
887
888 /* handle inexactly overlapping matches between mappings */
889 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
890 if (!(capabilities & BDI_CAP_MAP_DIRECT))
891 goto sharing_violation;
892 continue;
893 }
894
895 /* we've found a VMA we can share */
896 atomic_inc(&vma->vm_usage);
897
898 vml->vma = vma;
899 result = (void *) vma->vm_start;
900 goto shared;
901 }
902
David Howells165b2392007-03-22 00:11:24 -0800903 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 vma = NULL;
905
906 /* obtain the address at which to make a shared mapping
907 * - this is the hook for quasi-memory character devices to
908 * tell us the location of a shared mapping
909 */
910 if (file && file->f_op->get_unmapped_area) {
911 addr = file->f_op->get_unmapped_area(file, addr, len,
912 pgoff, flags);
913 if (IS_ERR((void *) addr)) {
914 ret = addr;
915 if (ret != (unsigned long) -ENOSYS)
916 goto error;
917
918 /* the driver refused to tell us where to site
919 * the mapping so we'll have to attempt to copy
920 * it */
921 ret = (unsigned long) -ENODEV;
922 if (!(capabilities & BDI_CAP_MAP_COPY))
923 goto error;
924
925 capabilities &= ~BDI_CAP_MAP_DIRECT;
926 }
927 }
928 }
929
930 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800931 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 if (!vma)
933 goto error_getting_vma;
934
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 INIT_LIST_HEAD(&vma->anon_vma_node);
936 atomic_set(&vma->vm_usage, 1);
937 if (file)
938 get_file(file);
939 vma->vm_file = file;
940 vma->vm_flags = vm_flags;
941 vma->vm_start = addr;
942 vma->vm_end = addr + len;
943 vma->vm_pgoff = pgoff;
944
945 vml->vma = vma;
946
947 /* set up the mapping */
948 if (file && vma->vm_flags & VM_SHARED)
949 ret = do_mmap_shared_file(vma, len);
950 else
951 ret = do_mmap_private(vma, len);
952 if (ret < 0)
953 goto error;
954
955 /* okay... we have a mapping; now we have to register it */
956 result = (void *) vma->vm_start;
957
958 if (vma->vm_flags & VM_MAPPED_COPY) {
959 realalloc += kobjsize(result);
960 askedalloc += len;
961 }
962
963 realalloc += kobjsize(vma);
964 askedalloc += sizeof(*vma);
965
966 current->mm->total_vm += len >> PAGE_SHIFT;
967
968 add_nommu_vma(vma);
969
970 shared:
971 realalloc += kobjsize(vml);
972 askedalloc += sizeof(*vml);
973
David Howells30340972006-09-27 01:50:20 -0700974 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
976 up_write(&nommu_vma_sem);
977
978 if (prot & PROT_EXEC)
979 flush_icache_range((unsigned long) result,
980 (unsigned long) result + len);
981
982#ifdef DEBUG
983 printk("do_mmap:\n");
984 show_process_blocks();
985#endif
986
987 return (unsigned long) result;
988
989 error:
990 up_write(&nommu_vma_sem);
991 kfree(vml);
992 if (vma) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -0700993 if (vma->vm_file)
994 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 kfree(vma);
996 }
997 return ret;
998
999 sharing_violation:
1000 up_write(&nommu_vma_sem);
1001 printk("Attempt to share mismatched mappings\n");
1002 kfree(vml);
1003 return -EINVAL;
1004
1005 error_getting_vma:
1006 up_write(&nommu_vma_sem);
1007 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001008 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 len, current->pid);
1010 show_free_areas();
1011 return -ENOMEM;
1012
1013 error_getting_vml:
1014 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1015 len, current->pid);
1016 show_free_areas();
1017 return -ENOMEM;
1018}
Paul Mundtb5073172007-07-21 04:37:25 -07001019EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020
1021/*
1022 * handle mapping disposal for uClinux
1023 */
1024static void put_vma(struct vm_area_struct *vma)
1025{
1026 if (vma) {
1027 down_write(&nommu_vma_sem);
1028
1029 if (atomic_dec_and_test(&vma->vm_usage)) {
1030 delete_nommu_vma(vma);
1031
1032 if (vma->vm_ops && vma->vm_ops->close)
1033 vma->vm_ops->close(vma);
1034
1035 /* IO memory and memory shared directly out of the pagecache from
1036 * ramfs/tmpfs mustn't be released here */
1037 if (vma->vm_flags & VM_MAPPED_COPY) {
1038 realalloc -= kobjsize((void *) vma->vm_start);
1039 askedalloc -= vma->vm_end - vma->vm_start;
1040 kfree((void *) vma->vm_start);
1041 }
1042
1043 realalloc -= kobjsize(vma);
1044 askedalloc -= sizeof(*vma);
1045
1046 if (vma->vm_file)
1047 fput(vma->vm_file);
1048 kfree(vma);
1049 }
1050
1051 up_write(&nommu_vma_sem);
1052 }
1053}
1054
David Howells30340972006-09-27 01:50:20 -07001055/*
1056 * release a mapping
1057 * - under NOMMU conditions the parameters must match exactly to the mapping to
1058 * be removed
1059 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1061{
1062 struct vm_list_struct *vml, **parent;
1063 unsigned long end = addr + len;
1064
1065#ifdef DEBUG
1066 printk("do_munmap:\n");
1067#endif
1068
David Howells30340972006-09-27 01:50:20 -07001069 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1070 if ((*parent)->vma->vm_start > addr)
1071 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001073 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 goto found;
David Howells30340972006-09-27 01:50:20 -07001075 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076
1077 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1078 current->pid, current->comm, (void *) addr);
1079 return -EINVAL;
1080
1081 found:
1082 vml = *parent;
1083
1084 put_vma(vml->vma);
1085
1086 *parent = vml->next;
1087 realalloc -= kobjsize(vml);
1088 askedalloc -= sizeof(*vml);
1089 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001090
1091 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 mm->total_vm -= len >> PAGE_SHIFT;
1093
1094#ifdef DEBUG
1095 show_process_blocks();
1096#endif
1097
1098 return 0;
1099}
Paul Mundtb5073172007-07-21 04:37:25 -07001100EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101
David Howells30340972006-09-27 01:50:20 -07001102asmlinkage long sys_munmap(unsigned long addr, size_t len)
1103{
1104 int ret;
1105 struct mm_struct *mm = current->mm;
1106
1107 down_write(&mm->mmap_sem);
1108 ret = do_munmap(mm, addr, len);
1109 up_write(&mm->mmap_sem);
1110 return ret;
1111}
1112
1113/*
1114 * Release all mappings
1115 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116void exit_mmap(struct mm_struct * mm)
1117{
1118 struct vm_list_struct *tmp;
1119
1120 if (mm) {
1121#ifdef DEBUG
1122 printk("Exit_mmap:\n");
1123#endif
1124
1125 mm->total_vm = 0;
1126
1127 while ((tmp = mm->context.vmlist)) {
1128 mm->context.vmlist = tmp->next;
1129 put_vma(tmp->vma);
1130
1131 realalloc -= kobjsize(tmp);
1132 askedalloc -= sizeof(*tmp);
1133 kfree(tmp);
1134 }
1135
1136#ifdef DEBUG
1137 show_process_blocks();
1138#endif
1139 }
1140}
1141
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142unsigned long do_brk(unsigned long addr, unsigned long len)
1143{
1144 return -ENOMEM;
1145}
1146
1147/*
David Howells6fa5f802006-09-27 01:50:21 -07001148 * expand (or shrink) an existing mapping, potentially moving it at the same
1149 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 *
David Howells6fa5f802006-09-27 01:50:21 -07001151 * under NOMMU conditions, we only permit changing a mapping's size, and only
1152 * as long as it stays within the hole allocated by the kmalloc() call in
1153 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 *
David Howells6fa5f802006-09-27 01:50:21 -07001155 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 */
1157unsigned long do_mremap(unsigned long addr,
1158 unsigned long old_len, unsigned long new_len,
1159 unsigned long flags, unsigned long new_addr)
1160{
David Howells6fa5f802006-09-27 01:50:21 -07001161 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
1163 /* insanity checks first */
1164 if (new_len == 0)
1165 return (unsigned long) -EINVAL;
1166
1167 if (flags & MREMAP_FIXED && new_addr != addr)
1168 return (unsigned long) -EINVAL;
1169
David Howells6fa5f802006-09-27 01:50:21 -07001170 vma = find_vma_exact(current->mm, addr);
1171 if (!vma)
1172 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173
David Howells6fa5f802006-09-27 01:50:21 -07001174 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 return (unsigned long) -EFAULT;
1176
David Howells6fa5f802006-09-27 01:50:21 -07001177 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 return (unsigned long) -EPERM;
1179
1180 if (new_len > kobjsize((void *) addr))
1181 return (unsigned long) -ENOMEM;
1182
1183 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001184 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185
1186 askedalloc -= old_len;
1187 askedalloc += new_len;
1188
David Howells6fa5f802006-09-27 01:50:21 -07001189 return vma->vm_start;
1190}
Paul Mundtb5073172007-07-21 04:37:25 -07001191EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001192
1193asmlinkage unsigned long sys_mremap(unsigned long addr,
1194 unsigned long old_len, unsigned long new_len,
1195 unsigned long flags, unsigned long new_addr)
1196{
1197 unsigned long ret;
1198
1199 down_write(&current->mm->mmap_sem);
1200 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1201 up_write(&current->mm->mmap_sem);
1202 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203}
1204
Linus Torvalds6aab3412005-11-28 14:34:23 -08001205struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001206 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207{
1208 return NULL;
1209}
1210
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1212 unsigned long to, unsigned long size, pgprot_t prot)
1213{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001214 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1215 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216}
Luke Yang22c4af42006-07-14 00:24:09 -07001217EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218
1219void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1220{
1221}
1222
1223unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1224 unsigned long len, unsigned long pgoff, unsigned long flags)
1225{
1226 return -ENOMEM;
1227}
1228
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001229void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230{
1231}
1232
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233void unmap_mapping_range(struct address_space *mapping,
1234 loff_t const holebegin, loff_t const holelen,
1235 int even_cows)
1236{
1237}
Luke Yang22c4af42006-07-14 00:24:09 -07001238EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239
1240/*
David Howellsd56e03c2007-03-22 00:11:23 -08001241 * ask for an unmapped area at which to create a mapping on a file
1242 */
1243unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1244 unsigned long len, unsigned long pgoff,
1245 unsigned long flags)
1246{
1247 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1248 unsigned long, unsigned long);
1249
1250 get_area = current->mm->get_unmapped_area;
1251 if (file && file->f_op && file->f_op->get_unmapped_area)
1252 get_area = file->f_op->get_unmapped_area;
1253
1254 if (!get_area)
1255 return -ENOSYS;
1256
1257 return get_area(file, addr, len, pgoff, flags);
1258}
David Howellsd56e03c2007-03-22 00:11:23 -08001259EXPORT_SYMBOL(get_unmapped_area);
1260
1261/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 * Check that a process has enough memory to allocate a new virtual
1263 * mapping. 0 means there is enough memory for the allocation to
1264 * succeed and -ENOMEM implies there is not.
1265 *
1266 * We currently support three overcommit policies, which are set via the
1267 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1268 *
1269 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1270 * Additional code 2002 Jul 20 by Robert Love.
1271 *
1272 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1273 *
1274 * Note this is a helper function intended to be used by LSMs which
1275 * wish to use this logic.
1276 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001277int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278{
1279 unsigned long free, allowed;
1280
1281 vm_acct_memory(pages);
1282
1283 /*
1284 * Sometimes we want to use more memory than we have
1285 */
1286 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1287 return 0;
1288
1289 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1290 unsigned long n;
1291
Christoph Lameter347ce432006-06-30 01:55:35 -07001292 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293 free += nr_swap_pages;
1294
1295 /*
1296 * Any slabs which are created with the
1297 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1298 * which are reclaimable, under pressure. The dentry
1299 * cache and most inode caches should fall into this
1300 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001301 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302
1303 /*
1304 * Leave the last 3% for root
1305 */
1306 if (!cap_sys_admin)
1307 free -= free / 32;
1308
1309 if (free > pages)
1310 return 0;
1311
1312 /*
1313 * nr_free_pages() is very expensive on large systems,
1314 * only call if we're about to fail.
1315 */
1316 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001317
1318 /*
1319 * Leave reserved pages. The pages are not for anonymous pages.
1320 */
1321 if (n <= totalreserve_pages)
1322 goto error;
1323 else
1324 n -= totalreserve_pages;
1325
1326 /*
1327 * Leave the last 3% for root
1328 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 if (!cap_sys_admin)
1330 n -= n / 32;
1331 free += n;
1332
1333 if (free > pages)
1334 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001335
1336 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 }
1338
1339 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1340 /*
1341 * Leave the last 3% for root
1342 */
1343 if (!cap_sys_admin)
1344 allowed -= allowed / 32;
1345 allowed += total_swap_pages;
1346
1347 /* Don't let a single process grow too big:
1348 leave 3% of the size of this process for other processes */
1349 allowed -= current->mm->total_vm / 32;
1350
Simon Derr2f60f8d2005-08-04 19:52:03 -07001351 /*
1352 * cast `allowed' as a signed long because vm_committed_space
1353 * sometimes has a negative value
1354 */
1355 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001357error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 vm_unacct_memory(pages);
1359
1360 return -ENOMEM;
1361}
1362
1363int in_gate_area_no_task(unsigned long addr)
1364{
1365 return 0;
1366}
David Howellsb0e15192006-01-06 00:11:42 -08001367
Nick Piggind0217ac2007-07-19 01:47:03 -07001368int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001369{
1370 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001371 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001372}
Paul Mundtb5073172007-07-21 04:37:25 -07001373EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001374
1375/*
1376 * Access another process' address space.
1377 * - source/target buffer must be kernel space
1378 */
1379int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1380{
David Howells0ec76a12006-09-27 01:50:15 -07001381 struct vm_area_struct *vma;
1382 struct mm_struct *mm;
1383
1384 if (addr + len < addr)
1385 return 0;
1386
1387 mm = get_task_mm(tsk);
1388 if (!mm)
1389 return 0;
1390
1391 down_read(&mm->mmap_sem);
1392
1393 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001394 vma = find_vma(mm, addr);
1395 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001396 /* don't overrun this mapping */
1397 if (addr + len >= vma->vm_end)
1398 len = vma->vm_end - addr;
1399
1400 /* only read or write mappings where it is permitted */
David Howellsd00c7b92006-09-27 01:50:19 -07001401 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001402 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b92006-09-27 01:50:19 -07001403 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001404 len -= copy_from_user(buf, (void *) addr, len);
1405 else
1406 len = 0;
1407 } else {
1408 len = 0;
1409 }
1410
1411 up_read(&mm->mmap_sem);
1412 mmput(mm);
1413 return len;
1414}