blob: 42fb84e9e8152819701d3da1cd449c30a0466db0 [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);
Wu, Bryan6a04de62007-04-11 23:28:47 -070047EXPORT_SYMBOL(num_physpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
49/* list of shareable VMAs */
50struct rb_root nommu_vma_tree = RB_ROOT;
51DECLARE_RWSEM(nommu_vma_sem);
52
53struct vm_operations_struct generic_file_vm_ops = {
54};
55
56/*
57 * Handle all mappings that got truncated by a "truncate()"
58 * system call.
59 *
60 * NOTE! We have to be ready to update the memory sharing
61 * between the file and the memory map for a potential last
62 * incomplete page. Ugly, but necessary.
63 */
64int vmtruncate(struct inode *inode, loff_t offset)
65{
66 struct address_space *mapping = inode->i_mapping;
67 unsigned long limit;
68
69 if (inode->i_size < offset)
70 goto do_expand;
71 i_size_write(inode, offset);
72
73 truncate_inode_pages(mapping, offset);
74 goto out_truncate;
75
76do_expand:
77 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
78 if (limit != RLIM_INFINITY && offset > limit)
79 goto out_sig;
80 if (offset > inode->i_sb->s_maxbytes)
81 goto out;
82 i_size_write(inode, offset);
83
84out_truncate:
85 if (inode->i_op && inode->i_op->truncate)
86 inode->i_op->truncate(inode);
87 return 0;
88out_sig:
89 send_sig(SIGXFSZ, current, 0);
90out:
91 return -EFBIG;
92}
93
94EXPORT_SYMBOL(vmtruncate);
95
96/*
97 * Return the total memory allocated for this pointer, not
98 * just what the caller asked for.
99 *
100 * Doesn't have to be accurate, i.e. may have races.
101 */
102unsigned int kobjsize(const void *objp)
103{
104 struct page *page;
105
106 if (!objp || !((page = virt_to_page(objp))))
107 return 0;
108
109 if (PageSlab(page))
110 return ksize(objp);
111
112 BUG_ON(page->index < 0);
113 BUG_ON(page->index >= MAX_ORDER);
114
115 return (PAGE_SIZE << page->index);
116}
117
118/*
David Howells7b4d5b82006-09-27 01:50:18 -0700119 * get a list of pages in an address range belonging to the specified process
120 * and indicate the VMA that covers each page
121 * - this is potentially dodgy as we may end incrementing the page count of a
122 * slab page or a secondary page from a compound page
123 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 */
125int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
126 unsigned long start, int len, int write, int force,
127 struct page **pages, struct vm_area_struct **vmas)
128{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700129 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700130 unsigned long vm_flags;
131 int i;
132
133 /* calculate required read or write permissions.
134 * - if 'force' is set, we only require the "MAY" flags.
135 */
136 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
137 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700140 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700141 if (!vma)
142 goto finish_or_fault;
143
144 /* protect what we can, including chardevs */
145 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
146 !(vm_flags & vma->vm_flags))
147 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700148
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 if (pages) {
150 pages[i] = virt_to_page(start);
151 if (pages[i])
152 page_cache_get(pages[i]);
153 }
154 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700155 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 start += PAGE_SIZE;
157 }
David Howells7b4d5b82006-09-27 01:50:18 -0700158
159 return i;
160
161finish_or_fault:
162 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000164EXPORT_SYMBOL(get_user_pages);
165
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166DEFINE_RWLOCK(vmlist_lock);
167struct vm_struct *vmlist;
168
169void vfree(void *addr)
170{
171 kfree(addr);
172}
Paul Mundtb5073172007-07-21 04:37:25 -0700173EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
Al Virodd0fc662005-10-07 07:46:04 +0100175void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
177 /*
178 * kmalloc doesn't like __GFP_HIGHMEM for some reason
179 */
Nick Piggin84097512006-03-22 00:08:34 -0800180 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181}
Paul Mundtb5073172007-07-21 04:37:25 -0700182EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
184struct page * vmalloc_to_page(void *addr)
185{
186 return virt_to_page(addr);
187}
Paul Mundtb5073172007-07-21 04:37:25 -0700188EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190unsigned long vmalloc_to_pfn(void *addr)
191{
192 return page_to_pfn(virt_to_page(addr));
193}
Paul Mundtb5073172007-07-21 04:37:25 -0700194EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196long vread(char *buf, char *addr, unsigned long count)
197{
198 memcpy(buf, addr, count);
199 return count;
200}
201
202long vwrite(char *buf, char *addr, unsigned long count)
203{
204 /* Don't allow overflow */
205 if ((unsigned long) addr + count < count)
206 count = -(unsigned long) addr;
207
208 memcpy(addr, buf, count);
209 return(count);
210}
211
212/*
213 * vmalloc - allocate virtually continguos memory
214 *
215 * @size: allocation size
216 *
217 * Allocate enough pages to cover @size from the page level
218 * allocator and map them into continguos kernel virtual space.
219 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200220 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 * use __vmalloc() instead.
222 */
223void *vmalloc(unsigned long size)
224{
225 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
226}
Andrew Mortonf6138882006-02-28 16:59:18 -0800227EXPORT_SYMBOL(vmalloc);
228
229void *vmalloc_node(unsigned long size, int node)
230{
231 return vmalloc(size);
232}
233EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
Paul Mundtb5073172007-07-21 04:37:25 -0700235/**
236 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 * @size: allocation size
238 *
239 * Allocate enough 32bit PA addressable pages to cover @size from the
240 * page level allocator and map them into continguos kernel virtual space.
241 */
242void *vmalloc_32(unsigned long size)
243{
244 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
245}
Paul Mundtb5073172007-07-21 04:37:25 -0700246EXPORT_SYMBOL(vmalloc_32);
247
248/**
249 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
250 * @size: allocation size
251 *
252 * The resulting memory area is 32bit addressable and zeroed so it can be
253 * mapped to userspace without leaking data.
254 */
255void *vmalloc_32_user(unsigned long size)
256{
257 return __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
258}
259EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
262{
263 BUG();
264 return NULL;
265}
Paul Mundtb5073172007-07-21 04:37:25 -0700266EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
268void vunmap(void *addr)
269{
270 BUG();
271}
Paul Mundtb5073172007-07-21 04:37:25 -0700272EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
274/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700275 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
276 * have one.
277 */
278void __attribute__((weak)) vmalloc_sync_all(void)
279{
280}
281
Paul Mundtb5073172007-07-21 04:37:25 -0700282int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
283 struct page *page)
284{
285 return -EINVAL;
286}
287EXPORT_SYMBOL(vm_insert_page);
288
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700289/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 * sys_brk() for the most part doesn't need the global kernel
291 * lock, except when an application is doing something nasty
292 * like trying to un-brk an area that has already been mapped
293 * to a regular file. in this case, the unmapping will need
294 * to invoke file system routines that need the global lock.
295 */
296asmlinkage unsigned long sys_brk(unsigned long brk)
297{
298 struct mm_struct *mm = current->mm;
299
300 if (brk < mm->start_brk || brk > mm->context.end_brk)
301 return mm->brk;
302
303 if (mm->brk == brk)
304 return mm->brk;
305
306 /*
307 * Always allow shrinking brk
308 */
309 if (brk <= mm->brk) {
310 mm->brk = brk;
311 return brk;
312 }
313
314 /*
315 * Ok, looks good - let it rip.
316 */
317 return mm->brk = brk;
318}
319
320#ifdef DEBUG
321static void show_process_blocks(void)
322{
323 struct vm_list_struct *vml;
324
325 printk("Process blocks %d:", current->pid);
326
327 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
328 printk(" %p: %p", vml, vml->vma);
329 if (vml->vma)
330 printk(" (%d @%lx #%d)",
331 kobjsize((void *) vml->vma->vm_start),
332 vml->vma->vm_start,
333 atomic_read(&vml->vma->vm_usage));
334 printk(vml->next ? " ->" : ".\n");
335 }
336}
337#endif /* DEBUG */
338
David Howells30340972006-09-27 01:50:20 -0700339/*
340 * add a VMA into a process's mm_struct in the appropriate place in the list
341 * - should be called with mm->mmap_sem held writelocked
342 */
343static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
344{
345 struct vm_list_struct **ppv;
346
347 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
348 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
349 break;
350
351 vml->next = *ppv;
352 *ppv = vml;
353}
354
355/*
356 * look up the first VMA in which addr resides, NULL if none
357 * - should be called with mm->mmap_sem at least held readlocked
358 */
359struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
360{
361 struct vm_list_struct *loop, *vml;
362
363 /* search the vm_start ordered list */
364 vml = NULL;
365 for (loop = mm->context.vmlist; loop; loop = loop->next) {
366 if (loop->vma->vm_start > addr)
367 break;
368 vml = loop;
369 }
370
371 if (vml && vml->vma->vm_end > addr)
372 return vml->vma;
373
374 return NULL;
375}
376EXPORT_SYMBOL(find_vma);
377
378/*
David Howells930e6522006-09-27 01:50:22 -0700379 * find a VMA
380 * - we don't extend stack VMAs under NOMMU conditions
381 */
382struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
383{
384 return find_vma(mm, addr);
385}
386
Greg Ungerer57c8f632007-07-15 23:38:28 -0700387int expand_stack(struct vm_area_struct *vma, unsigned long address)
388{
389 return -ENOMEM;
390}
391
David Howells930e6522006-09-27 01:50:22 -0700392/*
David Howells6fa5f802006-09-27 01:50:21 -0700393 * look up the first VMA exactly that exactly matches addr
394 * - should be called with mm->mmap_sem at least held readlocked
395 */
396static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
397 unsigned long addr)
398{
399 struct vm_list_struct *vml;
400
401 /* search the vm_start ordered list */
402 for (vml = mm->context.vmlist; vml; vml = vml->next) {
403 if (vml->vma->vm_start == addr)
404 return vml->vma;
405 if (vml->vma->vm_start > addr)
406 break;
407 }
408
409 return NULL;
410}
411
412/*
David Howells30340972006-09-27 01:50:20 -0700413 * find a VMA in the global tree
414 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
416{
417 struct vm_area_struct *vma;
418 struct rb_node *n = nommu_vma_tree.rb_node;
419
420 while (n) {
421 vma = rb_entry(n, struct vm_area_struct, vm_rb);
422
423 if (start < vma->vm_start)
424 n = n->rb_left;
425 else if (start > vma->vm_start)
426 n = n->rb_right;
427 else
428 return vma;
429 }
430
431 return NULL;
432}
433
David Howells30340972006-09-27 01:50:20 -0700434/*
435 * add a VMA in the global tree
436 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437static void add_nommu_vma(struct vm_area_struct *vma)
438{
439 struct vm_area_struct *pvma;
440 struct address_space *mapping;
441 struct rb_node **p = &nommu_vma_tree.rb_node;
442 struct rb_node *parent = NULL;
443
444 /* add the VMA to the mapping */
445 if (vma->vm_file) {
446 mapping = vma->vm_file->f_mapping;
447
448 flush_dcache_mmap_lock(mapping);
449 vma_prio_tree_insert(vma, &mapping->i_mmap);
450 flush_dcache_mmap_unlock(mapping);
451 }
452
453 /* add the VMA to the master list */
454 while (*p) {
455 parent = *p;
456 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
457
458 if (vma->vm_start < pvma->vm_start) {
459 p = &(*p)->rb_left;
460 }
461 else if (vma->vm_start > pvma->vm_start) {
462 p = &(*p)->rb_right;
463 }
464 else {
465 /* mappings are at the same address - this can only
466 * happen for shared-mem chardevs and shared file
467 * mappings backed by ramfs/tmpfs */
468 BUG_ON(!(pvma->vm_flags & VM_SHARED));
469
470 if (vma < pvma)
471 p = &(*p)->rb_left;
472 else if (vma > pvma)
473 p = &(*p)->rb_right;
474 else
475 BUG();
476 }
477 }
478
479 rb_link_node(&vma->vm_rb, parent, p);
480 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
481}
482
David Howells30340972006-09-27 01:50:20 -0700483/*
484 * delete a VMA from the global list
485 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486static void delete_nommu_vma(struct vm_area_struct *vma)
487{
488 struct address_space *mapping;
489
490 /* remove the VMA from the mapping */
491 if (vma->vm_file) {
492 mapping = vma->vm_file->f_mapping;
493
494 flush_dcache_mmap_lock(mapping);
495 vma_prio_tree_remove(vma, &mapping->i_mmap);
496 flush_dcache_mmap_unlock(mapping);
497 }
498
499 /* remove from the master list */
500 rb_erase(&vma->vm_rb, &nommu_vma_tree);
501}
502
503/*
504 * determine whether a mapping should be permitted and, if so, what sort of
505 * mapping we're capable of supporting
506 */
507static int validate_mmap_request(struct file *file,
508 unsigned long addr,
509 unsigned long len,
510 unsigned long prot,
511 unsigned long flags,
512 unsigned long pgoff,
513 unsigned long *_capabilities)
514{
515 unsigned long capabilities;
516 unsigned long reqprot = prot;
517 int ret;
518
519 /* do the simple checks first */
520 if (flags & MAP_FIXED || addr) {
521 printk(KERN_DEBUG
522 "%d: Can't do fixed-address/overlay mmap of RAM\n",
523 current->pid);
524 return -EINVAL;
525 }
526
527 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
528 (flags & MAP_TYPE) != MAP_SHARED)
529 return -EINVAL;
530
Mike Frysingerf81cff02006-12-06 12:02:59 +1000531 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 return -EINVAL;
533
Mike Frysingerf81cff02006-12-06 12:02:59 +1000534 /* Careful about overflows.. */
535 len = PAGE_ALIGN(len);
536 if (!len || len > TASK_SIZE)
537 return -ENOMEM;
538
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 /* offset overflow? */
540 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000541 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
543 if (file) {
544 /* validate file mapping requests */
545 struct address_space *mapping;
546
547 /* files must support mmap */
548 if (!file->f_op || !file->f_op->mmap)
549 return -ENODEV;
550
551 /* work out if what we've got could possibly be shared
552 * - we support chardevs that provide their own "memory"
553 * - we support files/blockdevs that are memory backed
554 */
555 mapping = file->f_mapping;
556 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800557 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558
559 capabilities = 0;
560 if (mapping && mapping->backing_dev_info)
561 capabilities = mapping->backing_dev_info->capabilities;
562
563 if (!capabilities) {
564 /* no explicit capabilities set, so assume some
565 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800566 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 case S_IFREG:
568 case S_IFBLK:
569 capabilities = BDI_CAP_MAP_COPY;
570 break;
571
572 case S_IFCHR:
573 capabilities =
574 BDI_CAP_MAP_DIRECT |
575 BDI_CAP_READ_MAP |
576 BDI_CAP_WRITE_MAP;
577 break;
578
579 default:
580 return -EINVAL;
581 }
582 }
583
584 /* eliminate any capabilities that we can't support on this
585 * device */
586 if (!file->f_op->get_unmapped_area)
587 capabilities &= ~BDI_CAP_MAP_DIRECT;
588 if (!file->f_op->read)
589 capabilities &= ~BDI_CAP_MAP_COPY;
590
591 if (flags & MAP_SHARED) {
592 /* do checks for writing, appending and locking */
593 if ((prot & PROT_WRITE) &&
594 !(file->f_mode & FMODE_WRITE))
595 return -EACCES;
596
Josef Sipeke9536ae2006-12-08 02:37:21 -0800597 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 (file->f_mode & FMODE_WRITE))
599 return -EACCES;
600
Josef Sipeke9536ae2006-12-08 02:37:21 -0800601 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 return -EAGAIN;
603
604 if (!(capabilities & BDI_CAP_MAP_DIRECT))
605 return -ENODEV;
606
607 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
608 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
609 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
610 ) {
611 printk("MAP_SHARED not completely supported on !MMU\n");
612 return -EINVAL;
613 }
614
615 /* we mustn't privatise shared mappings */
616 capabilities &= ~BDI_CAP_MAP_COPY;
617 }
618 else {
619 /* we're going to read the file into private memory we
620 * allocate */
621 if (!(capabilities & BDI_CAP_MAP_COPY))
622 return -ENODEV;
623
624 /* we don't permit a private writable mapping to be
625 * shared with the backing device */
626 if (prot & PROT_WRITE)
627 capabilities &= ~BDI_CAP_MAP_DIRECT;
628 }
629
630 /* handle executable mappings and implied executable
631 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800632 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if (prot & PROT_EXEC)
634 return -EPERM;
635 }
636 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
637 /* handle implication of PROT_EXEC by PROT_READ */
638 if (current->personality & READ_IMPLIES_EXEC) {
639 if (capabilities & BDI_CAP_EXEC_MAP)
640 prot |= PROT_EXEC;
641 }
642 }
643 else if ((prot & PROT_READ) &&
644 (prot & PROT_EXEC) &&
645 !(capabilities & BDI_CAP_EXEC_MAP)
646 ) {
647 /* backing file is not executable, try to copy */
648 capabilities &= ~BDI_CAP_MAP_DIRECT;
649 }
650 }
651 else {
652 /* anonymous mappings are always memory backed and can be
653 * privately mapped
654 */
655 capabilities = BDI_CAP_MAP_COPY;
656
657 /* handle PROT_EXEC implication by PROT_READ */
658 if ((prot & PROT_READ) &&
659 (current->personality & READ_IMPLIES_EXEC))
660 prot |= PROT_EXEC;
661 }
662
663 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400664 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 if (ret < 0)
666 return ret;
667
668 /* looks okay */
669 *_capabilities = capabilities;
670 return 0;
671}
672
673/*
674 * we've determined that we can make the mapping, now translate what we
675 * now know into VMA flags
676 */
677static unsigned long determine_vm_flags(struct file *file,
678 unsigned long prot,
679 unsigned long flags,
680 unsigned long capabilities)
681{
682 unsigned long vm_flags;
683
684 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
685 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
686 /* vm_flags |= mm->def_flags; */
687
688 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
689 /* attempt to share read-only copies of mapped file chunks */
690 if (file && !(prot & PROT_WRITE))
691 vm_flags |= VM_MAYSHARE;
692 }
693 else {
694 /* overlay a shareable mapping on the backing device or inode
695 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
696 * romfs/cramfs */
697 if (flags & MAP_SHARED)
698 vm_flags |= VM_MAYSHARE | VM_SHARED;
699 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
700 vm_flags |= VM_MAYSHARE;
701 }
702
703 /* refuse to let anyone share private mappings with this process if
704 * it's being traced - otherwise breakpoints set in it may interfere
705 * with another untraced process
706 */
707 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
708 vm_flags &= ~VM_MAYSHARE;
709
710 return vm_flags;
711}
712
713/*
714 * set up a shared mapping on a file
715 */
716static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
717{
718 int ret;
719
720 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
721 if (ret != -ENOSYS)
722 return ret;
723
724 /* getting an ENOSYS error indicates that direct mmap isn't
725 * possible (as opposed to tried but failed) so we'll fall
726 * through to making a private copy of the data and mapping
727 * that if we can */
728 return -ENODEV;
729}
730
731/*
732 * set up a private mapping or an anonymous shared mapping
733 */
734static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
735{
736 void *base;
737 int ret;
738
739 /* invoke the file's mapping function so that it can keep track of
740 * shared mappings on devices or memory
741 * - VM_MAYSHARE will be set if it may attempt to share
742 */
743 if (vma->vm_file) {
744 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
745 if (ret != -ENOSYS) {
746 /* shouldn't return success if we're not sharing */
747 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
748 return ret; /* success or a real error */
749 }
750
751 /* getting an ENOSYS error indicates that direct mmap isn't
752 * possible (as opposed to tried but failed) so we'll try to
753 * make a private copy of the data and map that instead */
754 }
755
756 /* allocate some memory to hold the mapping
757 * - note that this may not return a page-aligned address if the object
758 * we're allocating is smaller than a page
759 */
Nick Piggin84097512006-03-22 00:08:34 -0800760 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 if (!base)
762 goto enomem;
763
764 vma->vm_start = (unsigned long) base;
765 vma->vm_end = vma->vm_start + len;
766 vma->vm_flags |= VM_MAPPED_COPY;
767
768#ifdef WARN_ON_SLACK
769 if (len + WARN_ON_SLACK <= kobjsize(result))
770 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
771 len, current->pid, kobjsize(result) - len);
772#endif
773
774 if (vma->vm_file) {
775 /* read the contents of a file into the copy */
776 mm_segment_t old_fs;
777 loff_t fpos;
778
779 fpos = vma->vm_pgoff;
780 fpos <<= PAGE_SHIFT;
781
782 old_fs = get_fs();
783 set_fs(KERNEL_DS);
784 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
785 set_fs(old_fs);
786
787 if (ret < 0)
788 goto error_free;
789
790 /* clear the last little bit */
791 if (ret < len)
792 memset(base + ret, 0, len - ret);
793
794 } else {
795 /* if it's an anonymous mapping, then just clear it */
796 memset(base, 0, len);
797 }
798
799 return 0;
800
801error_free:
802 kfree(base);
803 vma->vm_start = 0;
804 return ret;
805
806enomem:
807 printk("Allocation of length %lu from process %d failed\n",
808 len, current->pid);
809 show_free_areas();
810 return -ENOMEM;
811}
812
813/*
814 * handle mapping creation for uClinux
815 */
816unsigned long do_mmap_pgoff(struct file *file,
817 unsigned long addr,
818 unsigned long len,
819 unsigned long prot,
820 unsigned long flags,
821 unsigned long pgoff)
822{
823 struct vm_list_struct *vml = NULL;
824 struct vm_area_struct *vma = NULL;
825 struct rb_node *rb;
826 unsigned long capabilities, vm_flags;
827 void *result;
828 int ret;
829
830 /* decide whether we should attempt the mapping, and if so what sort of
831 * mapping */
832 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
833 &capabilities);
834 if (ret < 0)
835 return ret;
836
837 /* we've determined that we can make the mapping, now translate what we
838 * now know into VMA flags */
839 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
840
841 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800842 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 if (!vml)
844 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
846 down_write(&nommu_vma_sem);
847
848 /* if we want to share, we need to check for VMAs created by other
849 * mmap() calls that overlap with our proposed mapping
850 * - we can only share with an exact match on most regular files
851 * - shared mappings on character devices and memory backed files are
852 * permitted to overlap inexactly as far as we are concerned for in
853 * these cases, sharing is handled in the driver or filesystem rather
854 * than here
855 */
856 if (vm_flags & VM_MAYSHARE) {
857 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
858 unsigned long vmpglen;
859
David Howells165b2392007-03-22 00:11:24 -0800860 /* suppress VMA sharing for shared regions */
861 if (vm_flags & VM_SHARED &&
862 capabilities & BDI_CAP_MAP_DIRECT)
863 goto dont_share_VMAs;
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
866 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
867
868 if (!(vma->vm_flags & VM_MAYSHARE))
869 continue;
870
871 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800872 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 continue;
874
875 if (vma->vm_pgoff >= pgoff + pglen)
876 continue;
877
878 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
879 vmpglen >>= PAGE_SHIFT;
880 if (pgoff >= vma->vm_pgoff + vmpglen)
881 continue;
882
883 /* handle inexactly overlapping matches between mappings */
884 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
885 if (!(capabilities & BDI_CAP_MAP_DIRECT))
886 goto sharing_violation;
887 continue;
888 }
889
890 /* we've found a VMA we can share */
891 atomic_inc(&vma->vm_usage);
892
893 vml->vma = vma;
894 result = (void *) vma->vm_start;
895 goto shared;
896 }
897
David Howells165b2392007-03-22 00:11:24 -0800898 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 vma = NULL;
900
901 /* obtain the address at which to make a shared mapping
902 * - this is the hook for quasi-memory character devices to
903 * tell us the location of a shared mapping
904 */
905 if (file && file->f_op->get_unmapped_area) {
906 addr = file->f_op->get_unmapped_area(file, addr, len,
907 pgoff, flags);
908 if (IS_ERR((void *) addr)) {
909 ret = addr;
910 if (ret != (unsigned long) -ENOSYS)
911 goto error;
912
913 /* the driver refused to tell us where to site
914 * the mapping so we'll have to attempt to copy
915 * it */
916 ret = (unsigned long) -ENODEV;
917 if (!(capabilities & BDI_CAP_MAP_COPY))
918 goto error;
919
920 capabilities &= ~BDI_CAP_MAP_DIRECT;
921 }
922 }
923 }
924
925 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800926 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 if (!vma)
928 goto error_getting_vma;
929
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 INIT_LIST_HEAD(&vma->anon_vma_node);
931 atomic_set(&vma->vm_usage, 1);
932 if (file)
933 get_file(file);
934 vma->vm_file = file;
935 vma->vm_flags = vm_flags;
936 vma->vm_start = addr;
937 vma->vm_end = addr + len;
938 vma->vm_pgoff = pgoff;
939
940 vml->vma = vma;
941
942 /* set up the mapping */
943 if (file && vma->vm_flags & VM_SHARED)
944 ret = do_mmap_shared_file(vma, len);
945 else
946 ret = do_mmap_private(vma, len);
947 if (ret < 0)
948 goto error;
949
950 /* okay... we have a mapping; now we have to register it */
951 result = (void *) vma->vm_start;
952
953 if (vma->vm_flags & VM_MAPPED_COPY) {
954 realalloc += kobjsize(result);
955 askedalloc += len;
956 }
957
958 realalloc += kobjsize(vma);
959 askedalloc += sizeof(*vma);
960
961 current->mm->total_vm += len >> PAGE_SHIFT;
962
963 add_nommu_vma(vma);
964
965 shared:
966 realalloc += kobjsize(vml);
967 askedalloc += sizeof(*vml);
968
David Howells30340972006-09-27 01:50:20 -0700969 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970
971 up_write(&nommu_vma_sem);
972
973 if (prot & PROT_EXEC)
974 flush_icache_range((unsigned long) result,
975 (unsigned long) result + len);
976
977#ifdef DEBUG
978 printk("do_mmap:\n");
979 show_process_blocks();
980#endif
981
982 return (unsigned long) result;
983
984 error:
985 up_write(&nommu_vma_sem);
986 kfree(vml);
987 if (vma) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -0700988 if (vma->vm_file)
989 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 kfree(vma);
991 }
992 return ret;
993
994 sharing_violation:
995 up_write(&nommu_vma_sem);
996 printk("Attempt to share mismatched mappings\n");
997 kfree(vml);
998 return -EINVAL;
999
1000 error_getting_vma:
1001 up_write(&nommu_vma_sem);
1002 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001003 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 len, current->pid);
1005 show_free_areas();
1006 return -ENOMEM;
1007
1008 error_getting_vml:
1009 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1010 len, current->pid);
1011 show_free_areas();
1012 return -ENOMEM;
1013}
Paul Mundtb5073172007-07-21 04:37:25 -07001014EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015
1016/*
1017 * handle mapping disposal for uClinux
1018 */
1019static void put_vma(struct vm_area_struct *vma)
1020{
1021 if (vma) {
1022 down_write(&nommu_vma_sem);
1023
1024 if (atomic_dec_and_test(&vma->vm_usage)) {
1025 delete_nommu_vma(vma);
1026
1027 if (vma->vm_ops && vma->vm_ops->close)
1028 vma->vm_ops->close(vma);
1029
1030 /* IO memory and memory shared directly out of the pagecache from
1031 * ramfs/tmpfs mustn't be released here */
1032 if (vma->vm_flags & VM_MAPPED_COPY) {
1033 realalloc -= kobjsize((void *) vma->vm_start);
1034 askedalloc -= vma->vm_end - vma->vm_start;
1035 kfree((void *) vma->vm_start);
1036 }
1037
1038 realalloc -= kobjsize(vma);
1039 askedalloc -= sizeof(*vma);
1040
1041 if (vma->vm_file)
1042 fput(vma->vm_file);
1043 kfree(vma);
1044 }
1045
1046 up_write(&nommu_vma_sem);
1047 }
1048}
1049
David Howells30340972006-09-27 01:50:20 -07001050/*
1051 * release a mapping
1052 * - under NOMMU conditions the parameters must match exactly to the mapping to
1053 * be removed
1054 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1056{
1057 struct vm_list_struct *vml, **parent;
1058 unsigned long end = addr + len;
1059
1060#ifdef DEBUG
1061 printk("do_munmap:\n");
1062#endif
1063
David Howells30340972006-09-27 01:50:20 -07001064 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1065 if ((*parent)->vma->vm_start > addr)
1066 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001068 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 goto found;
David Howells30340972006-09-27 01:50:20 -07001070 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071
1072 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1073 current->pid, current->comm, (void *) addr);
1074 return -EINVAL;
1075
1076 found:
1077 vml = *parent;
1078
1079 put_vma(vml->vma);
1080
1081 *parent = vml->next;
1082 realalloc -= kobjsize(vml);
1083 askedalloc -= sizeof(*vml);
1084 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001085
1086 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 mm->total_vm -= len >> PAGE_SHIFT;
1088
1089#ifdef DEBUG
1090 show_process_blocks();
1091#endif
1092
1093 return 0;
1094}
Paul Mundtb5073172007-07-21 04:37:25 -07001095EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096
David Howells30340972006-09-27 01:50:20 -07001097asmlinkage long sys_munmap(unsigned long addr, size_t len)
1098{
1099 int ret;
1100 struct mm_struct *mm = current->mm;
1101
1102 down_write(&mm->mmap_sem);
1103 ret = do_munmap(mm, addr, len);
1104 up_write(&mm->mmap_sem);
1105 return ret;
1106}
1107
1108/*
1109 * Release all mappings
1110 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111void exit_mmap(struct mm_struct * mm)
1112{
1113 struct vm_list_struct *tmp;
1114
1115 if (mm) {
1116#ifdef DEBUG
1117 printk("Exit_mmap:\n");
1118#endif
1119
1120 mm->total_vm = 0;
1121
1122 while ((tmp = mm->context.vmlist)) {
1123 mm->context.vmlist = tmp->next;
1124 put_vma(tmp->vma);
1125
1126 realalloc -= kobjsize(tmp);
1127 askedalloc -= sizeof(*tmp);
1128 kfree(tmp);
1129 }
1130
1131#ifdef DEBUG
1132 show_process_blocks();
1133#endif
1134 }
1135}
1136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137unsigned long do_brk(unsigned long addr, unsigned long len)
1138{
1139 return -ENOMEM;
1140}
1141
1142/*
David Howells6fa5f802006-09-27 01:50:21 -07001143 * expand (or shrink) an existing mapping, potentially moving it at the same
1144 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 *
David Howells6fa5f802006-09-27 01:50:21 -07001146 * under NOMMU conditions, we only permit changing a mapping's size, and only
1147 * as long as it stays within the hole allocated by the kmalloc() call in
1148 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 *
David Howells6fa5f802006-09-27 01:50:21 -07001150 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 */
1152unsigned long do_mremap(unsigned long addr,
1153 unsigned long old_len, unsigned long new_len,
1154 unsigned long flags, unsigned long new_addr)
1155{
David Howells6fa5f802006-09-27 01:50:21 -07001156 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157
1158 /* insanity checks first */
1159 if (new_len == 0)
1160 return (unsigned long) -EINVAL;
1161
1162 if (flags & MREMAP_FIXED && new_addr != addr)
1163 return (unsigned long) -EINVAL;
1164
David Howells6fa5f802006-09-27 01:50:21 -07001165 vma = find_vma_exact(current->mm, addr);
1166 if (!vma)
1167 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168
David Howells6fa5f802006-09-27 01:50:21 -07001169 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 return (unsigned long) -EFAULT;
1171
David Howells6fa5f802006-09-27 01:50:21 -07001172 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 return (unsigned long) -EPERM;
1174
1175 if (new_len > kobjsize((void *) addr))
1176 return (unsigned long) -ENOMEM;
1177
1178 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001179 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180
1181 askedalloc -= old_len;
1182 askedalloc += new_len;
1183
David Howells6fa5f802006-09-27 01:50:21 -07001184 return vma->vm_start;
1185}
Paul Mundtb5073172007-07-21 04:37:25 -07001186EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001187
1188asmlinkage unsigned long sys_mremap(unsigned long addr,
1189 unsigned long old_len, unsigned long new_len,
1190 unsigned long flags, unsigned long new_addr)
1191{
1192 unsigned long ret;
1193
1194 down_write(&current->mm->mmap_sem);
1195 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1196 up_write(&current->mm->mmap_sem);
1197 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198}
1199
Linus Torvalds6aab3412005-11-28 14:34:23 -08001200struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001201 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202{
1203 return NULL;
1204}
1205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1207 unsigned long to, unsigned long size, pgprot_t prot)
1208{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001209 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1210 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211}
Luke Yang22c4af42006-07-14 00:24:09 -07001212EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213
1214void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1215{
1216}
1217
1218unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1219 unsigned long len, unsigned long pgoff, unsigned long flags)
1220{
1221 return -ENOMEM;
1222}
1223
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001224void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225{
1226}
1227
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228void unmap_mapping_range(struct address_space *mapping,
1229 loff_t const holebegin, loff_t const holelen,
1230 int even_cows)
1231{
1232}
Luke Yang22c4af42006-07-14 00:24:09 -07001233EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234
1235/*
David Howellsd56e03c2007-03-22 00:11:23 -08001236 * ask for an unmapped area at which to create a mapping on a file
1237 */
1238unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1239 unsigned long len, unsigned long pgoff,
1240 unsigned long flags)
1241{
1242 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1243 unsigned long, unsigned long);
1244
1245 get_area = current->mm->get_unmapped_area;
1246 if (file && file->f_op && file->f_op->get_unmapped_area)
1247 get_area = file->f_op->get_unmapped_area;
1248
1249 if (!get_area)
1250 return -ENOSYS;
1251
1252 return get_area(file, addr, len, pgoff, flags);
1253}
David Howellsd56e03c2007-03-22 00:11:23 -08001254EXPORT_SYMBOL(get_unmapped_area);
1255
1256/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 * Check that a process has enough memory to allocate a new virtual
1258 * mapping. 0 means there is enough memory for the allocation to
1259 * succeed and -ENOMEM implies there is not.
1260 *
1261 * We currently support three overcommit policies, which are set via the
1262 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1263 *
1264 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1265 * Additional code 2002 Jul 20 by Robert Love.
1266 *
1267 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1268 *
1269 * Note this is a helper function intended to be used by LSMs which
1270 * wish to use this logic.
1271 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001272int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273{
1274 unsigned long free, allowed;
1275
1276 vm_acct_memory(pages);
1277
1278 /*
1279 * Sometimes we want to use more memory than we have
1280 */
1281 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1282 return 0;
1283
1284 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1285 unsigned long n;
1286
Christoph Lameter347ce432006-06-30 01:55:35 -07001287 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 free += nr_swap_pages;
1289
1290 /*
1291 * Any slabs which are created with the
1292 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1293 * which are reclaimable, under pressure. The dentry
1294 * cache and most inode caches should fall into this
1295 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001296 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297
1298 /*
1299 * Leave the last 3% for root
1300 */
1301 if (!cap_sys_admin)
1302 free -= free / 32;
1303
1304 if (free > pages)
1305 return 0;
1306
1307 /*
1308 * nr_free_pages() is very expensive on large systems,
1309 * only call if we're about to fail.
1310 */
1311 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001312
1313 /*
1314 * Leave reserved pages. The pages are not for anonymous pages.
1315 */
1316 if (n <= totalreserve_pages)
1317 goto error;
1318 else
1319 n -= totalreserve_pages;
1320
1321 /*
1322 * Leave the last 3% for root
1323 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324 if (!cap_sys_admin)
1325 n -= n / 32;
1326 free += n;
1327
1328 if (free > pages)
1329 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001330
1331 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 }
1333
1334 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1335 /*
1336 * Leave the last 3% for root
1337 */
1338 if (!cap_sys_admin)
1339 allowed -= allowed / 32;
1340 allowed += total_swap_pages;
1341
1342 /* Don't let a single process grow too big:
1343 leave 3% of the size of this process for other processes */
1344 allowed -= current->mm->total_vm / 32;
1345
Simon Derr2f60f8d2005-08-04 19:52:03 -07001346 /*
1347 * cast `allowed' as a signed long because vm_committed_space
1348 * sometimes has a negative value
1349 */
1350 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001352error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 vm_unacct_memory(pages);
1354
1355 return -ENOMEM;
1356}
1357
1358int in_gate_area_no_task(unsigned long addr)
1359{
1360 return 0;
1361}
David Howellsb0e15192006-01-06 00:11:42 -08001362
Nick Piggind0217ac2007-07-19 01:47:03 -07001363int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001364{
1365 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001366 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001367}
Paul Mundtb5073172007-07-21 04:37:25 -07001368EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001369
1370/*
1371 * Access another process' address space.
1372 * - source/target buffer must be kernel space
1373 */
1374int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1375{
David Howells0ec76a12006-09-27 01:50:15 -07001376 struct vm_area_struct *vma;
1377 struct mm_struct *mm;
1378
1379 if (addr + len < addr)
1380 return 0;
1381
1382 mm = get_task_mm(tsk);
1383 if (!mm)
1384 return 0;
1385
1386 down_read(&mm->mmap_sem);
1387
1388 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001389 vma = find_vma(mm, addr);
1390 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001391 /* don't overrun this mapping */
1392 if (addr + len >= vma->vm_end)
1393 len = vma->vm_end - addr;
1394
1395 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07001396 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001397 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07001398 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001399 len -= copy_from_user(buf, (void *) addr, len);
1400 else
1401 len = 0;
1402 } else {
1403 len = 0;
1404 }
1405
1406 up_read(&mm->mmap_sem);
1407 mmput(mm);
1408 return len;
1409}