blob: 1b105d28949f5bf407d30b32007ecdbb95b9452e [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
Greg Ungerer66aa2b42005-09-12 11:18:10 +100057EXPORT_SYMBOL(vfree);
58EXPORT_SYMBOL(vmalloc_to_page);
59EXPORT_SYMBOL(vmalloc_32);
Luke Yang7a9166e2006-02-20 18:28:07 -080060EXPORT_SYMBOL(vmap);
61EXPORT_SYMBOL(vunmap);
Greg Ungerer66aa2b42005-09-12 11:18:10 +100062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063/*
64 * Handle all mappings that got truncated by a "truncate()"
65 * system call.
66 *
67 * NOTE! We have to be ready to update the memory sharing
68 * between the file and the memory map for a potential last
69 * incomplete page. Ugly, but necessary.
70 */
71int vmtruncate(struct inode *inode, loff_t offset)
72{
73 struct address_space *mapping = inode->i_mapping;
74 unsigned long limit;
75
76 if (inode->i_size < offset)
77 goto do_expand;
78 i_size_write(inode, offset);
79
80 truncate_inode_pages(mapping, offset);
81 goto out_truncate;
82
83do_expand:
84 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
85 if (limit != RLIM_INFINITY && offset > limit)
86 goto out_sig;
87 if (offset > inode->i_sb->s_maxbytes)
88 goto out;
89 i_size_write(inode, offset);
90
91out_truncate:
92 if (inode->i_op && inode->i_op->truncate)
93 inode->i_op->truncate(inode);
94 return 0;
95out_sig:
96 send_sig(SIGXFSZ, current, 0);
97out:
98 return -EFBIG;
99}
100
101EXPORT_SYMBOL(vmtruncate);
102
103/*
104 * Return the total memory allocated for this pointer, not
105 * just what the caller asked for.
106 *
107 * Doesn't have to be accurate, i.e. may have races.
108 */
109unsigned int kobjsize(const void *objp)
110{
111 struct page *page;
112
113 if (!objp || !((page = virt_to_page(objp))))
114 return 0;
115
116 if (PageSlab(page))
117 return ksize(objp);
118
119 BUG_ON(page->index < 0);
120 BUG_ON(page->index >= MAX_ORDER);
121
122 return (PAGE_SIZE << page->index);
123}
124
125/*
David Howells7b4d5b82006-09-27 01:50:18 -0700126 * get a list of pages in an address range belonging to the specified process
127 * and indicate the VMA that covers each page
128 * - this is potentially dodgy as we may end incrementing the page count of a
129 * slab page or a secondary page from a compound page
130 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 */
132int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
133 unsigned long start, int len, int write, int force,
134 struct page **pages, struct vm_area_struct **vmas)
135{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700136 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700137 unsigned long vm_flags;
138 int i;
139
140 /* calculate required read or write permissions.
141 * - if 'force' is set, we only require the "MAY" flags.
142 */
143 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
144 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700147 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700148 if (!vma)
149 goto finish_or_fault;
150
151 /* protect what we can, including chardevs */
152 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
153 !(vm_flags & vma->vm_flags))
154 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 if (pages) {
157 pages[i] = virt_to_page(start);
158 if (pages[i])
159 page_cache_get(pages[i]);
160 }
161 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700162 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 start += PAGE_SIZE;
164 }
David Howells7b4d5b82006-09-27 01:50:18 -0700165
166 return i;
167
168finish_or_fault:
169 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000172EXPORT_SYMBOL(get_user_pages);
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174DEFINE_RWLOCK(vmlist_lock);
175struct vm_struct *vmlist;
176
177void vfree(void *addr)
178{
179 kfree(addr);
180}
181
Al Virodd0fc662005-10-07 07:46:04 +0100182void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183{
184 /*
185 * kmalloc doesn't like __GFP_HIGHMEM for some reason
186 */
Nick Piggin84097512006-03-22 00:08:34 -0800187 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188}
189
190struct page * vmalloc_to_page(void *addr)
191{
192 return virt_to_page(addr);
193}
194
195unsigned long vmalloc_to_pfn(void *addr)
196{
197 return page_to_pfn(virt_to_page(addr));
198}
199
200
201long vread(char *buf, char *addr, unsigned long count)
202{
203 memcpy(buf, addr, count);
204 return count;
205}
206
207long vwrite(char *buf, char *addr, unsigned long count)
208{
209 /* Don't allow overflow */
210 if ((unsigned long) addr + count < count)
211 count = -(unsigned long) addr;
212
213 memcpy(addr, buf, count);
214 return(count);
215}
216
217/*
218 * vmalloc - allocate virtually continguos memory
219 *
220 * @size: allocation size
221 *
222 * Allocate enough pages to cover @size from the page level
223 * allocator and map them into continguos kernel virtual space.
224 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200225 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 * use __vmalloc() instead.
227 */
228void *vmalloc(unsigned long size)
229{
230 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
231}
Andrew Mortonf6138882006-02-28 16:59:18 -0800232EXPORT_SYMBOL(vmalloc);
233
234void *vmalloc_node(unsigned long size, int node)
235{
236 return vmalloc(size);
237}
238EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
240/*
241 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
242 *
243 * @size: allocation size
244 *
245 * Allocate enough 32bit PA addressable pages to cover @size from the
246 * page level allocator and map them into continguos kernel virtual space.
247 */
248void *vmalloc_32(unsigned long size)
249{
250 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
251}
252
253void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
254{
255 BUG();
256 return NULL;
257}
258
259void vunmap(void *addr)
260{
261 BUG();
262}
263
264/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700265 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
266 * have one.
267 */
268void __attribute__((weak)) vmalloc_sync_all(void)
269{
270}
271
272/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 * sys_brk() for the most part doesn't need the global kernel
274 * lock, except when an application is doing something nasty
275 * like trying to un-brk an area that has already been mapped
276 * to a regular file. in this case, the unmapping will need
277 * to invoke file system routines that need the global lock.
278 */
279asmlinkage unsigned long sys_brk(unsigned long brk)
280{
281 struct mm_struct *mm = current->mm;
282
283 if (brk < mm->start_brk || brk > mm->context.end_brk)
284 return mm->brk;
285
286 if (mm->brk == brk)
287 return mm->brk;
288
289 /*
290 * Always allow shrinking brk
291 */
292 if (brk <= mm->brk) {
293 mm->brk = brk;
294 return brk;
295 }
296
297 /*
298 * Ok, looks good - let it rip.
299 */
300 return mm->brk = brk;
301}
302
303#ifdef DEBUG
304static void show_process_blocks(void)
305{
306 struct vm_list_struct *vml;
307
308 printk("Process blocks %d:", current->pid);
309
310 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
311 printk(" %p: %p", vml, vml->vma);
312 if (vml->vma)
313 printk(" (%d @%lx #%d)",
314 kobjsize((void *) vml->vma->vm_start),
315 vml->vma->vm_start,
316 atomic_read(&vml->vma->vm_usage));
317 printk(vml->next ? " ->" : ".\n");
318 }
319}
320#endif /* DEBUG */
321
David Howells30340972006-09-27 01:50:20 -0700322/*
323 * add a VMA into a process's mm_struct in the appropriate place in the list
324 * - should be called with mm->mmap_sem held writelocked
325 */
326static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
327{
328 struct vm_list_struct **ppv;
329
330 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
331 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
332 break;
333
334 vml->next = *ppv;
335 *ppv = vml;
336}
337
338/*
339 * look up the first VMA in which addr resides, NULL if none
340 * - should be called with mm->mmap_sem at least held readlocked
341 */
342struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
343{
344 struct vm_list_struct *loop, *vml;
345
346 /* search the vm_start ordered list */
347 vml = NULL;
348 for (loop = mm->context.vmlist; loop; loop = loop->next) {
349 if (loop->vma->vm_start > addr)
350 break;
351 vml = loop;
352 }
353
354 if (vml && vml->vma->vm_end > addr)
355 return vml->vma;
356
357 return NULL;
358}
359EXPORT_SYMBOL(find_vma);
360
361/*
David Howells930e6522006-09-27 01:50:22 -0700362 * find a VMA
363 * - we don't extend stack VMAs under NOMMU conditions
364 */
365struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
366{
367 return find_vma(mm, addr);
368}
369
Greg Ungerer57c8f632007-07-15 23:38:28 -0700370int expand_stack(struct vm_area_struct *vma, unsigned long address)
371{
372 return -ENOMEM;
373}
374
David Howells930e6522006-09-27 01:50:22 -0700375/*
David Howells6fa5f802006-09-27 01:50:21 -0700376 * look up the first VMA exactly that exactly matches addr
377 * - should be called with mm->mmap_sem at least held readlocked
378 */
379static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
380 unsigned long addr)
381{
382 struct vm_list_struct *vml;
383
384 /* search the vm_start ordered list */
385 for (vml = mm->context.vmlist; vml; vml = vml->next) {
386 if (vml->vma->vm_start == addr)
387 return vml->vma;
388 if (vml->vma->vm_start > addr)
389 break;
390 }
391
392 return NULL;
393}
394
395/*
David Howells30340972006-09-27 01:50:20 -0700396 * find a VMA in the global tree
397 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
399{
400 struct vm_area_struct *vma;
401 struct rb_node *n = nommu_vma_tree.rb_node;
402
403 while (n) {
404 vma = rb_entry(n, struct vm_area_struct, vm_rb);
405
406 if (start < vma->vm_start)
407 n = n->rb_left;
408 else if (start > vma->vm_start)
409 n = n->rb_right;
410 else
411 return vma;
412 }
413
414 return NULL;
415}
416
David Howells30340972006-09-27 01:50:20 -0700417/*
418 * add a VMA in the global tree
419 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420static void add_nommu_vma(struct vm_area_struct *vma)
421{
422 struct vm_area_struct *pvma;
423 struct address_space *mapping;
424 struct rb_node **p = &nommu_vma_tree.rb_node;
425 struct rb_node *parent = NULL;
426
427 /* add the VMA to the mapping */
428 if (vma->vm_file) {
429 mapping = vma->vm_file->f_mapping;
430
431 flush_dcache_mmap_lock(mapping);
432 vma_prio_tree_insert(vma, &mapping->i_mmap);
433 flush_dcache_mmap_unlock(mapping);
434 }
435
436 /* add the VMA to the master list */
437 while (*p) {
438 parent = *p;
439 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
440
441 if (vma->vm_start < pvma->vm_start) {
442 p = &(*p)->rb_left;
443 }
444 else if (vma->vm_start > pvma->vm_start) {
445 p = &(*p)->rb_right;
446 }
447 else {
448 /* mappings are at the same address - this can only
449 * happen for shared-mem chardevs and shared file
450 * mappings backed by ramfs/tmpfs */
451 BUG_ON(!(pvma->vm_flags & VM_SHARED));
452
453 if (vma < pvma)
454 p = &(*p)->rb_left;
455 else if (vma > pvma)
456 p = &(*p)->rb_right;
457 else
458 BUG();
459 }
460 }
461
462 rb_link_node(&vma->vm_rb, parent, p);
463 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
464}
465
David Howells30340972006-09-27 01:50:20 -0700466/*
467 * delete a VMA from the global list
468 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469static void delete_nommu_vma(struct vm_area_struct *vma)
470{
471 struct address_space *mapping;
472
473 /* remove the VMA from the mapping */
474 if (vma->vm_file) {
475 mapping = vma->vm_file->f_mapping;
476
477 flush_dcache_mmap_lock(mapping);
478 vma_prio_tree_remove(vma, &mapping->i_mmap);
479 flush_dcache_mmap_unlock(mapping);
480 }
481
482 /* remove from the master list */
483 rb_erase(&vma->vm_rb, &nommu_vma_tree);
484}
485
486/*
487 * determine whether a mapping should be permitted and, if so, what sort of
488 * mapping we're capable of supporting
489 */
490static int validate_mmap_request(struct file *file,
491 unsigned long addr,
492 unsigned long len,
493 unsigned long prot,
494 unsigned long flags,
495 unsigned long pgoff,
496 unsigned long *_capabilities)
497{
498 unsigned long capabilities;
499 unsigned long reqprot = prot;
500 int ret;
501
502 /* do the simple checks first */
503 if (flags & MAP_FIXED || addr) {
504 printk(KERN_DEBUG
505 "%d: Can't do fixed-address/overlay mmap of RAM\n",
506 current->pid);
507 return -EINVAL;
508 }
509
510 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
511 (flags & MAP_TYPE) != MAP_SHARED)
512 return -EINVAL;
513
Mike Frysingerf81cff02006-12-06 12:02:59 +1000514 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 return -EINVAL;
516
Mike Frysingerf81cff02006-12-06 12:02:59 +1000517 /* Careful about overflows.. */
518 len = PAGE_ALIGN(len);
519 if (!len || len > TASK_SIZE)
520 return -ENOMEM;
521
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 /* offset overflow? */
523 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000524 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525
526 if (file) {
527 /* validate file mapping requests */
528 struct address_space *mapping;
529
530 /* files must support mmap */
531 if (!file->f_op || !file->f_op->mmap)
532 return -ENODEV;
533
534 /* work out if what we've got could possibly be shared
535 * - we support chardevs that provide their own "memory"
536 * - we support files/blockdevs that are memory backed
537 */
538 mapping = file->f_mapping;
539 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800540 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
542 capabilities = 0;
543 if (mapping && mapping->backing_dev_info)
544 capabilities = mapping->backing_dev_info->capabilities;
545
546 if (!capabilities) {
547 /* no explicit capabilities set, so assume some
548 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800549 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 case S_IFREG:
551 case S_IFBLK:
552 capabilities = BDI_CAP_MAP_COPY;
553 break;
554
555 case S_IFCHR:
556 capabilities =
557 BDI_CAP_MAP_DIRECT |
558 BDI_CAP_READ_MAP |
559 BDI_CAP_WRITE_MAP;
560 break;
561
562 default:
563 return -EINVAL;
564 }
565 }
566
567 /* eliminate any capabilities that we can't support on this
568 * device */
569 if (!file->f_op->get_unmapped_area)
570 capabilities &= ~BDI_CAP_MAP_DIRECT;
571 if (!file->f_op->read)
572 capabilities &= ~BDI_CAP_MAP_COPY;
573
574 if (flags & MAP_SHARED) {
575 /* do checks for writing, appending and locking */
576 if ((prot & PROT_WRITE) &&
577 !(file->f_mode & FMODE_WRITE))
578 return -EACCES;
579
Josef Sipeke9536ae2006-12-08 02:37:21 -0800580 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 (file->f_mode & FMODE_WRITE))
582 return -EACCES;
583
Josef Sipeke9536ae2006-12-08 02:37:21 -0800584 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 return -EAGAIN;
586
587 if (!(capabilities & BDI_CAP_MAP_DIRECT))
588 return -ENODEV;
589
590 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
591 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
592 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
593 ) {
594 printk("MAP_SHARED not completely supported on !MMU\n");
595 return -EINVAL;
596 }
597
598 /* we mustn't privatise shared mappings */
599 capabilities &= ~BDI_CAP_MAP_COPY;
600 }
601 else {
602 /* we're going to read the file into private memory we
603 * allocate */
604 if (!(capabilities & BDI_CAP_MAP_COPY))
605 return -ENODEV;
606
607 /* we don't permit a private writable mapping to be
608 * shared with the backing device */
609 if (prot & PROT_WRITE)
610 capabilities &= ~BDI_CAP_MAP_DIRECT;
611 }
612
613 /* handle executable mappings and implied executable
614 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800615 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (prot & PROT_EXEC)
617 return -EPERM;
618 }
619 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
620 /* handle implication of PROT_EXEC by PROT_READ */
621 if (current->personality & READ_IMPLIES_EXEC) {
622 if (capabilities & BDI_CAP_EXEC_MAP)
623 prot |= PROT_EXEC;
624 }
625 }
626 else if ((prot & PROT_READ) &&
627 (prot & PROT_EXEC) &&
628 !(capabilities & BDI_CAP_EXEC_MAP)
629 ) {
630 /* backing file is not executable, try to copy */
631 capabilities &= ~BDI_CAP_MAP_DIRECT;
632 }
633 }
634 else {
635 /* anonymous mappings are always memory backed and can be
636 * privately mapped
637 */
638 capabilities = BDI_CAP_MAP_COPY;
639
640 /* handle PROT_EXEC implication by PROT_READ */
641 if ((prot & PROT_READ) &&
642 (current->personality & READ_IMPLIES_EXEC))
643 prot |= PROT_EXEC;
644 }
645
646 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400647 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 if (ret < 0)
649 return ret;
650
651 /* looks okay */
652 *_capabilities = capabilities;
653 return 0;
654}
655
656/*
657 * we've determined that we can make the mapping, now translate what we
658 * now know into VMA flags
659 */
660static unsigned long determine_vm_flags(struct file *file,
661 unsigned long prot,
662 unsigned long flags,
663 unsigned long capabilities)
664{
665 unsigned long vm_flags;
666
667 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
668 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
669 /* vm_flags |= mm->def_flags; */
670
671 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
672 /* attempt to share read-only copies of mapped file chunks */
673 if (file && !(prot & PROT_WRITE))
674 vm_flags |= VM_MAYSHARE;
675 }
676 else {
677 /* overlay a shareable mapping on the backing device or inode
678 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
679 * romfs/cramfs */
680 if (flags & MAP_SHARED)
681 vm_flags |= VM_MAYSHARE | VM_SHARED;
682 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
683 vm_flags |= VM_MAYSHARE;
684 }
685
686 /* refuse to let anyone share private mappings with this process if
687 * it's being traced - otherwise breakpoints set in it may interfere
688 * with another untraced process
689 */
690 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
691 vm_flags &= ~VM_MAYSHARE;
692
693 return vm_flags;
694}
695
696/*
697 * set up a shared mapping on a file
698 */
699static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
700{
701 int ret;
702
703 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
704 if (ret != -ENOSYS)
705 return ret;
706
707 /* getting an ENOSYS error indicates that direct mmap isn't
708 * possible (as opposed to tried but failed) so we'll fall
709 * through to making a private copy of the data and mapping
710 * that if we can */
711 return -ENODEV;
712}
713
714/*
715 * set up a private mapping or an anonymous shared mapping
716 */
717static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
718{
719 void *base;
720 int ret;
721
722 /* invoke the file's mapping function so that it can keep track of
723 * shared mappings on devices or memory
724 * - VM_MAYSHARE will be set if it may attempt to share
725 */
726 if (vma->vm_file) {
727 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
728 if (ret != -ENOSYS) {
729 /* shouldn't return success if we're not sharing */
730 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
731 return ret; /* success or a real error */
732 }
733
734 /* getting an ENOSYS error indicates that direct mmap isn't
735 * possible (as opposed to tried but failed) so we'll try to
736 * make a private copy of the data and map that instead */
737 }
738
739 /* allocate some memory to hold the mapping
740 * - note that this may not return a page-aligned address if the object
741 * we're allocating is smaller than a page
742 */
Nick Piggin84097512006-03-22 00:08:34 -0800743 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 if (!base)
745 goto enomem;
746
747 vma->vm_start = (unsigned long) base;
748 vma->vm_end = vma->vm_start + len;
749 vma->vm_flags |= VM_MAPPED_COPY;
750
751#ifdef WARN_ON_SLACK
752 if (len + WARN_ON_SLACK <= kobjsize(result))
753 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
754 len, current->pid, kobjsize(result) - len);
755#endif
756
757 if (vma->vm_file) {
758 /* read the contents of a file into the copy */
759 mm_segment_t old_fs;
760 loff_t fpos;
761
762 fpos = vma->vm_pgoff;
763 fpos <<= PAGE_SHIFT;
764
765 old_fs = get_fs();
766 set_fs(KERNEL_DS);
767 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
768 set_fs(old_fs);
769
770 if (ret < 0)
771 goto error_free;
772
773 /* clear the last little bit */
774 if (ret < len)
775 memset(base + ret, 0, len - ret);
776
777 } else {
778 /* if it's an anonymous mapping, then just clear it */
779 memset(base, 0, len);
780 }
781
782 return 0;
783
784error_free:
785 kfree(base);
786 vma->vm_start = 0;
787 return ret;
788
789enomem:
790 printk("Allocation of length %lu from process %d failed\n",
791 len, current->pid);
792 show_free_areas();
793 return -ENOMEM;
794}
795
796/*
797 * handle mapping creation for uClinux
798 */
799unsigned long do_mmap_pgoff(struct file *file,
800 unsigned long addr,
801 unsigned long len,
802 unsigned long prot,
803 unsigned long flags,
804 unsigned long pgoff)
805{
806 struct vm_list_struct *vml = NULL;
807 struct vm_area_struct *vma = NULL;
808 struct rb_node *rb;
809 unsigned long capabilities, vm_flags;
810 void *result;
811 int ret;
812
813 /* decide whether we should attempt the mapping, and if so what sort of
814 * mapping */
815 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
816 &capabilities);
817 if (ret < 0)
818 return ret;
819
820 /* we've determined that we can make the mapping, now translate what we
821 * now know into VMA flags */
822 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
823
824 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800825 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 if (!vml)
827 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828
829 down_write(&nommu_vma_sem);
830
831 /* if we want to share, we need to check for VMAs created by other
832 * mmap() calls that overlap with our proposed mapping
833 * - we can only share with an exact match on most regular files
834 * - shared mappings on character devices and memory backed files are
835 * permitted to overlap inexactly as far as we are concerned for in
836 * these cases, sharing is handled in the driver or filesystem rather
837 * than here
838 */
839 if (vm_flags & VM_MAYSHARE) {
840 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
841 unsigned long vmpglen;
842
David Howells165b2392007-03-22 00:11:24 -0800843 /* suppress VMA sharing for shared regions */
844 if (vm_flags & VM_SHARED &&
845 capabilities & BDI_CAP_MAP_DIRECT)
846 goto dont_share_VMAs;
847
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
849 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
850
851 if (!(vma->vm_flags & VM_MAYSHARE))
852 continue;
853
854 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800855 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 continue;
857
858 if (vma->vm_pgoff >= pgoff + pglen)
859 continue;
860
861 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
862 vmpglen >>= PAGE_SHIFT;
863 if (pgoff >= vma->vm_pgoff + vmpglen)
864 continue;
865
866 /* handle inexactly overlapping matches between mappings */
867 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
868 if (!(capabilities & BDI_CAP_MAP_DIRECT))
869 goto sharing_violation;
870 continue;
871 }
872
873 /* we've found a VMA we can share */
874 atomic_inc(&vma->vm_usage);
875
876 vml->vma = vma;
877 result = (void *) vma->vm_start;
878 goto shared;
879 }
880
David Howells165b2392007-03-22 00:11:24 -0800881 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 vma = NULL;
883
884 /* obtain the address at which to make a shared mapping
885 * - this is the hook for quasi-memory character devices to
886 * tell us the location of a shared mapping
887 */
888 if (file && file->f_op->get_unmapped_area) {
889 addr = file->f_op->get_unmapped_area(file, addr, len,
890 pgoff, flags);
891 if (IS_ERR((void *) addr)) {
892 ret = addr;
893 if (ret != (unsigned long) -ENOSYS)
894 goto error;
895
896 /* the driver refused to tell us where to site
897 * the mapping so we'll have to attempt to copy
898 * it */
899 ret = (unsigned long) -ENODEV;
900 if (!(capabilities & BDI_CAP_MAP_COPY))
901 goto error;
902
903 capabilities &= ~BDI_CAP_MAP_DIRECT;
904 }
905 }
906 }
907
908 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800909 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 if (!vma)
911 goto error_getting_vma;
912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 INIT_LIST_HEAD(&vma->anon_vma_node);
914 atomic_set(&vma->vm_usage, 1);
915 if (file)
916 get_file(file);
917 vma->vm_file = file;
918 vma->vm_flags = vm_flags;
919 vma->vm_start = addr;
920 vma->vm_end = addr + len;
921 vma->vm_pgoff = pgoff;
922
923 vml->vma = vma;
924
925 /* set up the mapping */
926 if (file && vma->vm_flags & VM_SHARED)
927 ret = do_mmap_shared_file(vma, len);
928 else
929 ret = do_mmap_private(vma, len);
930 if (ret < 0)
931 goto error;
932
933 /* okay... we have a mapping; now we have to register it */
934 result = (void *) vma->vm_start;
935
936 if (vma->vm_flags & VM_MAPPED_COPY) {
937 realalloc += kobjsize(result);
938 askedalloc += len;
939 }
940
941 realalloc += kobjsize(vma);
942 askedalloc += sizeof(*vma);
943
944 current->mm->total_vm += len >> PAGE_SHIFT;
945
946 add_nommu_vma(vma);
947
948 shared:
949 realalloc += kobjsize(vml);
950 askedalloc += sizeof(*vml);
951
David Howells30340972006-09-27 01:50:20 -0700952 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
954 up_write(&nommu_vma_sem);
955
956 if (prot & PROT_EXEC)
957 flush_icache_range((unsigned long) result,
958 (unsigned long) result + len);
959
960#ifdef DEBUG
961 printk("do_mmap:\n");
962 show_process_blocks();
963#endif
964
965 return (unsigned long) result;
966
967 error:
968 up_write(&nommu_vma_sem);
969 kfree(vml);
970 if (vma) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -0700971 if (vma->vm_file)
972 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 kfree(vma);
974 }
975 return ret;
976
977 sharing_violation:
978 up_write(&nommu_vma_sem);
979 printk("Attempt to share mismatched mappings\n");
980 kfree(vml);
981 return -EINVAL;
982
983 error_getting_vma:
984 up_write(&nommu_vma_sem);
985 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000986 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 len, current->pid);
988 show_free_areas();
989 return -ENOMEM;
990
991 error_getting_vml:
992 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
993 len, current->pid);
994 show_free_areas();
995 return -ENOMEM;
996}
997
998/*
999 * handle mapping disposal for uClinux
1000 */
1001static void put_vma(struct vm_area_struct *vma)
1002{
1003 if (vma) {
1004 down_write(&nommu_vma_sem);
1005
1006 if (atomic_dec_and_test(&vma->vm_usage)) {
1007 delete_nommu_vma(vma);
1008
1009 if (vma->vm_ops && vma->vm_ops->close)
1010 vma->vm_ops->close(vma);
1011
1012 /* IO memory and memory shared directly out of the pagecache from
1013 * ramfs/tmpfs mustn't be released here */
1014 if (vma->vm_flags & VM_MAPPED_COPY) {
1015 realalloc -= kobjsize((void *) vma->vm_start);
1016 askedalloc -= vma->vm_end - vma->vm_start;
1017 kfree((void *) vma->vm_start);
1018 }
1019
1020 realalloc -= kobjsize(vma);
1021 askedalloc -= sizeof(*vma);
1022
1023 if (vma->vm_file)
1024 fput(vma->vm_file);
1025 kfree(vma);
1026 }
1027
1028 up_write(&nommu_vma_sem);
1029 }
1030}
1031
David Howells30340972006-09-27 01:50:20 -07001032/*
1033 * release a mapping
1034 * - under NOMMU conditions the parameters must match exactly to the mapping to
1035 * be removed
1036 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1038{
1039 struct vm_list_struct *vml, **parent;
1040 unsigned long end = addr + len;
1041
1042#ifdef DEBUG
1043 printk("do_munmap:\n");
1044#endif
1045
David Howells30340972006-09-27 01:50:20 -07001046 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1047 if ((*parent)->vma->vm_start > addr)
1048 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001050 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 goto found;
David Howells30340972006-09-27 01:50:20 -07001052 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053
1054 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1055 current->pid, current->comm, (void *) addr);
1056 return -EINVAL;
1057
1058 found:
1059 vml = *parent;
1060
1061 put_vma(vml->vma);
1062
1063 *parent = vml->next;
1064 realalloc -= kobjsize(vml);
1065 askedalloc -= sizeof(*vml);
1066 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001067
1068 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 mm->total_vm -= len >> PAGE_SHIFT;
1070
1071#ifdef DEBUG
1072 show_process_blocks();
1073#endif
1074
1075 return 0;
1076}
1077
David Howells30340972006-09-27 01:50:20 -07001078asmlinkage long sys_munmap(unsigned long addr, size_t len)
1079{
1080 int ret;
1081 struct mm_struct *mm = current->mm;
1082
1083 down_write(&mm->mmap_sem);
1084 ret = do_munmap(mm, addr, len);
1085 up_write(&mm->mmap_sem);
1086 return ret;
1087}
1088
1089/*
1090 * Release all mappings
1091 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092void exit_mmap(struct mm_struct * mm)
1093{
1094 struct vm_list_struct *tmp;
1095
1096 if (mm) {
1097#ifdef DEBUG
1098 printk("Exit_mmap:\n");
1099#endif
1100
1101 mm->total_vm = 0;
1102
1103 while ((tmp = mm->context.vmlist)) {
1104 mm->context.vmlist = tmp->next;
1105 put_vma(tmp->vma);
1106
1107 realalloc -= kobjsize(tmp);
1108 askedalloc -= sizeof(*tmp);
1109 kfree(tmp);
1110 }
1111
1112#ifdef DEBUG
1113 show_process_blocks();
1114#endif
1115 }
1116}
1117
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118unsigned long do_brk(unsigned long addr, unsigned long len)
1119{
1120 return -ENOMEM;
1121}
1122
1123/*
David Howells6fa5f802006-09-27 01:50:21 -07001124 * expand (or shrink) an existing mapping, potentially moving it at the same
1125 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 *
David Howells6fa5f802006-09-27 01:50:21 -07001127 * under NOMMU conditions, we only permit changing a mapping's size, and only
1128 * as long as it stays within the hole allocated by the kmalloc() call in
1129 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 *
David Howells6fa5f802006-09-27 01:50:21 -07001131 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 */
1133unsigned long do_mremap(unsigned long addr,
1134 unsigned long old_len, unsigned long new_len,
1135 unsigned long flags, unsigned long new_addr)
1136{
David Howells6fa5f802006-09-27 01:50:21 -07001137 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138
1139 /* insanity checks first */
1140 if (new_len == 0)
1141 return (unsigned long) -EINVAL;
1142
1143 if (flags & MREMAP_FIXED && new_addr != addr)
1144 return (unsigned long) -EINVAL;
1145
David Howells6fa5f802006-09-27 01:50:21 -07001146 vma = find_vma_exact(current->mm, addr);
1147 if (!vma)
1148 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149
David Howells6fa5f802006-09-27 01:50:21 -07001150 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 return (unsigned long) -EFAULT;
1152
David Howells6fa5f802006-09-27 01:50:21 -07001153 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 return (unsigned long) -EPERM;
1155
1156 if (new_len > kobjsize((void *) addr))
1157 return (unsigned long) -ENOMEM;
1158
1159 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001160 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
1162 askedalloc -= old_len;
1163 askedalloc += new_len;
1164
David Howells6fa5f802006-09-27 01:50:21 -07001165 return vma->vm_start;
1166}
1167
1168asmlinkage unsigned long sys_mremap(unsigned long addr,
1169 unsigned long old_len, unsigned long new_len,
1170 unsigned long flags, unsigned long new_addr)
1171{
1172 unsigned long ret;
1173
1174 down_write(&current->mm->mmap_sem);
1175 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1176 up_write(&current->mm->mmap_sem);
1177 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178}
1179
Linus Torvalds6aab3412005-11-28 14:34:23 -08001180struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001181 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182{
1183 return NULL;
1184}
1185
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1187 unsigned long to, unsigned long size, pgprot_t prot)
1188{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001189 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1190 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191}
Luke Yang22c4af42006-07-14 00:24:09 -07001192EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193
1194void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1195{
1196}
1197
1198unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1199 unsigned long len, unsigned long pgoff, unsigned long flags)
1200{
1201 return -ENOMEM;
1202}
1203
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001204void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205{
1206}
1207
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208void unmap_mapping_range(struct address_space *mapping,
1209 loff_t const holebegin, loff_t const holelen,
1210 int even_cows)
1211{
1212}
Luke Yang22c4af42006-07-14 00:24:09 -07001213EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214
1215/*
David Howellsd56e03c2007-03-22 00:11:23 -08001216 * ask for an unmapped area at which to create a mapping on a file
1217 */
1218unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1219 unsigned long len, unsigned long pgoff,
1220 unsigned long flags)
1221{
1222 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1223 unsigned long, unsigned long);
1224
1225 get_area = current->mm->get_unmapped_area;
1226 if (file && file->f_op && file->f_op->get_unmapped_area)
1227 get_area = file->f_op->get_unmapped_area;
1228
1229 if (!get_area)
1230 return -ENOSYS;
1231
1232 return get_area(file, addr, len, pgoff, flags);
1233}
1234
1235EXPORT_SYMBOL(get_unmapped_area);
1236
1237/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238 * Check that a process has enough memory to allocate a new virtual
1239 * mapping. 0 means there is enough memory for the allocation to
1240 * succeed and -ENOMEM implies there is not.
1241 *
1242 * We currently support three overcommit policies, which are set via the
1243 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1244 *
1245 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1246 * Additional code 2002 Jul 20 by Robert Love.
1247 *
1248 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1249 *
1250 * Note this is a helper function intended to be used by LSMs which
1251 * wish to use this logic.
1252 */
1253int __vm_enough_memory(long pages, int cap_sys_admin)
1254{
1255 unsigned long free, allowed;
1256
1257 vm_acct_memory(pages);
1258
1259 /*
1260 * Sometimes we want to use more memory than we have
1261 */
1262 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1263 return 0;
1264
1265 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1266 unsigned long n;
1267
Christoph Lameter347ce432006-06-30 01:55:35 -07001268 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 free += nr_swap_pages;
1270
1271 /*
1272 * Any slabs which are created with the
1273 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1274 * which are reclaimable, under pressure. The dentry
1275 * cache and most inode caches should fall into this
1276 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001277 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
1279 /*
1280 * Leave the last 3% for root
1281 */
1282 if (!cap_sys_admin)
1283 free -= free / 32;
1284
1285 if (free > pages)
1286 return 0;
1287
1288 /*
1289 * nr_free_pages() is very expensive on large systems,
1290 * only call if we're about to fail.
1291 */
1292 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001293
1294 /*
1295 * Leave reserved pages. The pages are not for anonymous pages.
1296 */
1297 if (n <= totalreserve_pages)
1298 goto error;
1299 else
1300 n -= totalreserve_pages;
1301
1302 /*
1303 * Leave the last 3% for root
1304 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305 if (!cap_sys_admin)
1306 n -= n / 32;
1307 free += n;
1308
1309 if (free > pages)
1310 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001311
1312 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 }
1314
1315 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1316 /*
1317 * Leave the last 3% for root
1318 */
1319 if (!cap_sys_admin)
1320 allowed -= allowed / 32;
1321 allowed += total_swap_pages;
1322
1323 /* Don't let a single process grow too big:
1324 leave 3% of the size of this process for other processes */
1325 allowed -= current->mm->total_vm / 32;
1326
Simon Derr2f60f8d2005-08-04 19:52:03 -07001327 /*
1328 * cast `allowed' as a signed long because vm_committed_space
1329 * sometimes has a negative value
1330 */
1331 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001333error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 vm_unacct_memory(pages);
1335
1336 return -ENOMEM;
1337}
1338
1339int in_gate_area_no_task(unsigned long addr)
1340{
1341 return 0;
1342}
David Howellsb0e15192006-01-06 00:11:42 -08001343
Nick Piggind0217ac2007-07-19 01:47:03 -07001344int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001345{
1346 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001347 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001348}
David Howells0ec76a12006-09-27 01:50:15 -07001349
1350/*
1351 * Access another process' address space.
1352 * - source/target buffer must be kernel space
1353 */
1354int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1355{
David Howells0ec76a12006-09-27 01:50:15 -07001356 struct vm_area_struct *vma;
1357 struct mm_struct *mm;
1358
1359 if (addr + len < addr)
1360 return 0;
1361
1362 mm = get_task_mm(tsk);
1363 if (!mm)
1364 return 0;
1365
1366 down_read(&mm->mmap_sem);
1367
1368 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001369 vma = find_vma(mm, addr);
1370 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001371 /* don't overrun this mapping */
1372 if (addr + len >= vma->vm_end)
1373 len = vma->vm_end - addr;
1374
1375 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07001376 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001377 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07001378 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001379 len -= copy_from_user(buf, (void *) addr, len);
1380 else
1381 len = 0;
1382 } else {
1383 len = 0;
1384 }
1385
1386 up_read(&mm->mmap_sem);
1387 mmput(mm);
1388 return len;
1389}