blob: ed75bc962fbe913f8a5835c0a9bc43170582dd7f [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>
Paul Mundtf905bc42008-02-04 22:29:59 -080013 * Copyright (c) 2007 Paul Mundt <lethal@linux-sh.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 */
15
David Howellsf2b85442007-10-29 13:15:39 +000016#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/mm.h>
18#include <linux/mman.h>
19#include <linux/swap.h>
20#include <linux/file.h>
21#include <linux/highmem.h>
22#include <linux/pagemap.h>
23#include <linux/slab.h>
24#include <linux/vmalloc.h>
Roland McGrathfa8e26c2008-07-25 19:45:50 -070025#include <linux/tracehook.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/blkdev.h>
27#include <linux/backing-dev.h>
28#include <linux/mount.h>
29#include <linux/personality.h>
30#include <linux/security.h>
31#include <linux/syscalls.h>
32
33#include <asm/uaccess.h>
34#include <asm/tlb.h>
35#include <asm/tlbflush.h>
36
37void *high_memory;
38struct page *mem_map;
39unsigned long max_mapnr;
40unsigned long num_physpages;
41unsigned long askedalloc, realalloc;
Alan Cox80119ef2008-05-23 13:04:31 -070042atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
44int sysctl_overcommit_ratio = 50; /* default is 50% */
45int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
46int heap_stack_gap = 0;
47
48EXPORT_SYMBOL(mem_map);
Wu, Bryan6a04de62007-04-11 23:28:47 -070049EXPORT_SYMBOL(num_physpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
51/* list of shareable VMAs */
52struct rb_root nommu_vma_tree = RB_ROOT;
53DECLARE_RWSEM(nommu_vma_sem);
54
55struct vm_operations_struct generic_file_vm_ops = {
56};
57
58/*
59 * Handle all mappings that got truncated by a "truncate()"
60 * system call.
61 *
62 * NOTE! We have to be ready to update the memory sharing
63 * between the file and the memory map for a potential last
64 * incomplete page. Ugly, but necessary.
65 */
66int vmtruncate(struct inode *inode, loff_t offset)
67{
68 struct address_space *mapping = inode->i_mapping;
69 unsigned long limit;
70
71 if (inode->i_size < offset)
72 goto do_expand;
73 i_size_write(inode, offset);
74
75 truncate_inode_pages(mapping, offset);
76 goto out_truncate;
77
78do_expand:
79 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
80 if (limit != RLIM_INFINITY && offset > limit)
81 goto out_sig;
82 if (offset > inode->i_sb->s_maxbytes)
83 goto out;
84 i_size_write(inode, offset);
85
86out_truncate:
87 if (inode->i_op && inode->i_op->truncate)
88 inode->i_op->truncate(inode);
89 return 0;
90out_sig:
91 send_sig(SIGXFSZ, current, 0);
92out:
93 return -EFBIG;
94}
95
96EXPORT_SYMBOL(vmtruncate);
97
98/*
99 * Return the total memory allocated for this pointer, not
100 * just what the caller asked for.
101 *
102 * Doesn't have to be accurate, i.e. may have races.
103 */
104unsigned int kobjsize(const void *objp)
105{
106 struct page *page;
107
Michael Hennerich4016a132008-04-28 02:13:38 -0700108 /*
109 * If the object we have should not have ksize performed on it,
110 * return size of 0
111 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900112 if (!objp || !virt_addr_valid(objp))
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700113 return 0;
114
115 page = virt_to_head_page(objp);
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700116
117 /*
118 * If the allocator sets PageSlab, we know the pointer came from
119 * kmalloc().
120 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 if (PageSlab(page))
122 return ksize(objp);
123
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700124 /*
125 * The ksize() function is only guaranteed to work for pointers
Paul Mundt5a1603b2008-06-12 16:29:55 +0900126 * returned by kmalloc(). So handle arbitrary pointers here.
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700127 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900128 return PAGE_SIZE << compound_order(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129}
130
131/*
David Howells7b4d5b82006-09-27 01:50:18 -0700132 * get a list of pages in an address range belonging to the specified process
133 * and indicate the VMA that covers each page
134 * - this is potentially dodgy as we may end incrementing the page count of a
135 * slab page or a secondary page from a compound page
136 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 */
138int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
139 unsigned long start, int len, int write, int force,
140 struct page **pages, struct vm_area_struct **vmas)
141{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700142 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700143 unsigned long vm_flags;
144 int i;
145
146 /* calculate required read or write permissions.
147 * - if 'force' is set, we only require the "MAY" flags.
148 */
149 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
150 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700153 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700154 if (!vma)
155 goto finish_or_fault;
156
157 /* protect what we can, including chardevs */
158 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
159 !(vm_flags & vma->vm_flags))
160 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 if (pages) {
163 pages[i] = virt_to_page(start);
164 if (pages[i])
165 page_cache_get(pages[i]);
166 }
167 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700168 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 start += PAGE_SIZE;
170 }
David Howells7b4d5b82006-09-27 01:50:18 -0700171
172 return i;
173
174finish_or_fault:
175 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000177EXPORT_SYMBOL(get_user_pages);
178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179DEFINE_RWLOCK(vmlist_lock);
180struct vm_struct *vmlist;
181
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800182void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183{
184 kfree(addr);
185}
Paul Mundtb5073172007-07-21 04:37:25 -0700186EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Al Virodd0fc662005-10-07 07:46:04 +0100188void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189{
190 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200191 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
192 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 */
Nick Piggin84097512006-03-22 00:08:34 -0800194 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
Paul Mundtb5073172007-07-21 04:37:25 -0700196EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Paul Mundtf905bc42008-02-04 22:29:59 -0800198void *vmalloc_user(unsigned long size)
199{
200 void *ret;
201
202 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
203 PAGE_KERNEL);
204 if (ret) {
205 struct vm_area_struct *vma;
206
207 down_write(&current->mm->mmap_sem);
208 vma = find_vma(current->mm, (unsigned long)ret);
209 if (vma)
210 vma->vm_flags |= VM_USERMAP;
211 up_write(&current->mm->mmap_sem);
212 }
213
214 return ret;
215}
216EXPORT_SYMBOL(vmalloc_user);
217
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800218struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
220 return virt_to_page(addr);
221}
Paul Mundtb5073172007-07-21 04:37:25 -0700222EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800224unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225{
226 return page_to_pfn(virt_to_page(addr));
227}
Paul Mundtb5073172007-07-21 04:37:25 -0700228EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230long vread(char *buf, char *addr, unsigned long count)
231{
232 memcpy(buf, addr, count);
233 return count;
234}
235
236long vwrite(char *buf, char *addr, unsigned long count)
237{
238 /* Don't allow overflow */
239 if ((unsigned long) addr + count < count)
240 count = -(unsigned long) addr;
241
242 memcpy(addr, buf, count);
243 return(count);
244}
245
246/*
247 * vmalloc - allocate virtually continguos memory
248 *
249 * @size: allocation size
250 *
251 * Allocate enough pages to cover @size from the page level
252 * allocator and map them into continguos kernel virtual space.
253 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200254 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 * use __vmalloc() instead.
256 */
257void *vmalloc(unsigned long size)
258{
259 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
260}
Andrew Mortonf6138882006-02-28 16:59:18 -0800261EXPORT_SYMBOL(vmalloc);
262
263void *vmalloc_node(unsigned long size, int node)
264{
265 return vmalloc(size);
266}
267EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Paul Mundt1af446e2008-08-04 16:01:47 +0900269#ifndef PAGE_KERNEL_EXEC
270# define PAGE_KERNEL_EXEC PAGE_KERNEL
271#endif
272
273/**
274 * vmalloc_exec - allocate virtually contiguous, executable memory
275 * @size: allocation size
276 *
277 * Kernel-internal function to allocate enough pages to cover @size
278 * the page level allocator and map them into contiguous and
279 * executable kernel virtual space.
280 *
281 * For tight control over page level allocator and protection flags
282 * use __vmalloc() instead.
283 */
284
285void *vmalloc_exec(unsigned long size)
286{
287 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
288}
289
Paul Mundtb5073172007-07-21 04:37:25 -0700290/**
291 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 * @size: allocation size
293 *
294 * Allocate enough 32bit PA addressable pages to cover @size from the
295 * page level allocator and map them into continguos kernel virtual space.
296 */
297void *vmalloc_32(unsigned long size)
298{
299 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
300}
Paul Mundtb5073172007-07-21 04:37:25 -0700301EXPORT_SYMBOL(vmalloc_32);
302
303/**
304 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
305 * @size: allocation size
306 *
307 * The resulting memory area is 32bit addressable and zeroed so it can be
308 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800309 *
310 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
311 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700312 */
313void *vmalloc_32_user(unsigned long size)
314{
Paul Mundtf905bc42008-02-04 22:29:59 -0800315 /*
316 * We'll have to sort out the ZONE_DMA bits for 64-bit,
317 * but for now this can simply use vmalloc_user() directly.
318 */
319 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700320}
321EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
323void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
324{
325 BUG();
326 return NULL;
327}
Paul Mundtb5073172007-07-21 04:37:25 -0700328EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800330void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331{
332 BUG();
333}
Paul Mundtb5073172007-07-21 04:37:25 -0700334EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
336/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700337 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
338 * have one.
339 */
340void __attribute__((weak)) vmalloc_sync_all(void)
341{
342}
343
Paul Mundtb5073172007-07-21 04:37:25 -0700344int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
345 struct page *page)
346{
347 return -EINVAL;
348}
349EXPORT_SYMBOL(vm_insert_page);
350
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700351/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 * sys_brk() for the most part doesn't need the global kernel
353 * lock, except when an application is doing something nasty
354 * like trying to un-brk an area that has already been mapped
355 * to a regular file. in this case, the unmapping will need
356 * to invoke file system routines that need the global lock.
357 */
358asmlinkage unsigned long sys_brk(unsigned long brk)
359{
360 struct mm_struct *mm = current->mm;
361
362 if (brk < mm->start_brk || brk > mm->context.end_brk)
363 return mm->brk;
364
365 if (mm->brk == brk)
366 return mm->brk;
367
368 /*
369 * Always allow shrinking brk
370 */
371 if (brk <= mm->brk) {
372 mm->brk = brk;
373 return brk;
374 }
375
376 /*
377 * Ok, looks good - let it rip.
378 */
379 return mm->brk = brk;
380}
381
382#ifdef DEBUG
383static void show_process_blocks(void)
384{
385 struct vm_list_struct *vml;
386
387 printk("Process blocks %d:", current->pid);
388
389 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
390 printk(" %p: %p", vml, vml->vma);
391 if (vml->vma)
392 printk(" (%d @%lx #%d)",
393 kobjsize((void *) vml->vma->vm_start),
394 vml->vma->vm_start,
395 atomic_read(&vml->vma->vm_usage));
396 printk(vml->next ? " ->" : ".\n");
397 }
398}
399#endif /* DEBUG */
400
David Howells30340972006-09-27 01:50:20 -0700401/*
402 * add a VMA into a process's mm_struct in the appropriate place in the list
403 * - should be called with mm->mmap_sem held writelocked
404 */
405static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
406{
407 struct vm_list_struct **ppv;
408
409 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
410 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
411 break;
412
413 vml->next = *ppv;
414 *ppv = vml;
415}
416
417/*
418 * look up the first VMA in which addr resides, NULL if none
419 * - should be called with mm->mmap_sem at least held readlocked
420 */
421struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
422{
423 struct vm_list_struct *loop, *vml;
424
425 /* search the vm_start ordered list */
426 vml = NULL;
427 for (loop = mm->context.vmlist; loop; loop = loop->next) {
428 if (loop->vma->vm_start > addr)
429 break;
430 vml = loop;
431 }
432
433 if (vml && vml->vma->vm_end > addr)
434 return vml->vma;
435
436 return NULL;
437}
438EXPORT_SYMBOL(find_vma);
439
440/*
David Howells930e6522006-09-27 01:50:22 -0700441 * find a VMA
442 * - we don't extend stack VMAs under NOMMU conditions
443 */
444struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
445{
446 return find_vma(mm, addr);
447}
448
Greg Ungerer57c8f632007-07-15 23:38:28 -0700449int expand_stack(struct vm_area_struct *vma, unsigned long address)
450{
451 return -ENOMEM;
452}
453
David Howells930e6522006-09-27 01:50:22 -0700454/*
David Howells6fa5f802006-09-27 01:50:21 -0700455 * look up the first VMA exactly that exactly matches addr
456 * - should be called with mm->mmap_sem at least held readlocked
457 */
458static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
459 unsigned long addr)
460{
461 struct vm_list_struct *vml;
462
463 /* search the vm_start ordered list */
464 for (vml = mm->context.vmlist; vml; vml = vml->next) {
465 if (vml->vma->vm_start == addr)
466 return vml->vma;
467 if (vml->vma->vm_start > addr)
468 break;
469 }
470
471 return NULL;
472}
473
474/*
David Howells30340972006-09-27 01:50:20 -0700475 * find a VMA in the global tree
476 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
478{
479 struct vm_area_struct *vma;
480 struct rb_node *n = nommu_vma_tree.rb_node;
481
482 while (n) {
483 vma = rb_entry(n, struct vm_area_struct, vm_rb);
484
485 if (start < vma->vm_start)
486 n = n->rb_left;
487 else if (start > vma->vm_start)
488 n = n->rb_right;
489 else
490 return vma;
491 }
492
493 return NULL;
494}
495
David Howells30340972006-09-27 01:50:20 -0700496/*
497 * add a VMA in the global tree
498 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499static void add_nommu_vma(struct vm_area_struct *vma)
500{
501 struct vm_area_struct *pvma;
502 struct address_space *mapping;
503 struct rb_node **p = &nommu_vma_tree.rb_node;
504 struct rb_node *parent = NULL;
505
506 /* add the VMA to the mapping */
507 if (vma->vm_file) {
508 mapping = vma->vm_file->f_mapping;
509
510 flush_dcache_mmap_lock(mapping);
511 vma_prio_tree_insert(vma, &mapping->i_mmap);
512 flush_dcache_mmap_unlock(mapping);
513 }
514
515 /* add the VMA to the master list */
516 while (*p) {
517 parent = *p;
518 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
519
520 if (vma->vm_start < pvma->vm_start) {
521 p = &(*p)->rb_left;
522 }
523 else if (vma->vm_start > pvma->vm_start) {
524 p = &(*p)->rb_right;
525 }
526 else {
527 /* mappings are at the same address - this can only
528 * happen for shared-mem chardevs and shared file
529 * mappings backed by ramfs/tmpfs */
530 BUG_ON(!(pvma->vm_flags & VM_SHARED));
531
532 if (vma < pvma)
533 p = &(*p)->rb_left;
534 else if (vma > pvma)
535 p = &(*p)->rb_right;
536 else
537 BUG();
538 }
539 }
540
541 rb_link_node(&vma->vm_rb, parent, p);
542 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
543}
544
David Howells30340972006-09-27 01:50:20 -0700545/*
546 * delete a VMA from the global list
547 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548static void delete_nommu_vma(struct vm_area_struct *vma)
549{
550 struct address_space *mapping;
551
552 /* remove the VMA from the mapping */
553 if (vma->vm_file) {
554 mapping = vma->vm_file->f_mapping;
555
556 flush_dcache_mmap_lock(mapping);
557 vma_prio_tree_remove(vma, &mapping->i_mmap);
558 flush_dcache_mmap_unlock(mapping);
559 }
560
561 /* remove from the master list */
562 rb_erase(&vma->vm_rb, &nommu_vma_tree);
563}
564
565/*
566 * determine whether a mapping should be permitted and, if so, what sort of
567 * mapping we're capable of supporting
568 */
569static int validate_mmap_request(struct file *file,
570 unsigned long addr,
571 unsigned long len,
572 unsigned long prot,
573 unsigned long flags,
574 unsigned long pgoff,
575 unsigned long *_capabilities)
576{
577 unsigned long capabilities;
578 unsigned long reqprot = prot;
579 int ret;
580
581 /* do the simple checks first */
582 if (flags & MAP_FIXED || addr) {
583 printk(KERN_DEBUG
584 "%d: Can't do fixed-address/overlay mmap of RAM\n",
585 current->pid);
586 return -EINVAL;
587 }
588
589 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
590 (flags & MAP_TYPE) != MAP_SHARED)
591 return -EINVAL;
592
Mike Frysingerf81cff02006-12-06 12:02:59 +1000593 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 return -EINVAL;
595
Mike Frysingerf81cff02006-12-06 12:02:59 +1000596 /* Careful about overflows.. */
597 len = PAGE_ALIGN(len);
598 if (!len || len > TASK_SIZE)
599 return -ENOMEM;
600
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 /* offset overflow? */
602 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000603 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604
605 if (file) {
606 /* validate file mapping requests */
607 struct address_space *mapping;
608
609 /* files must support mmap */
610 if (!file->f_op || !file->f_op->mmap)
611 return -ENODEV;
612
613 /* work out if what we've got could possibly be shared
614 * - we support chardevs that provide their own "memory"
615 * - we support files/blockdevs that are memory backed
616 */
617 mapping = file->f_mapping;
618 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800619 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620
621 capabilities = 0;
622 if (mapping && mapping->backing_dev_info)
623 capabilities = mapping->backing_dev_info->capabilities;
624
625 if (!capabilities) {
626 /* no explicit capabilities set, so assume some
627 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800628 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 case S_IFREG:
630 case S_IFBLK:
631 capabilities = BDI_CAP_MAP_COPY;
632 break;
633
634 case S_IFCHR:
635 capabilities =
636 BDI_CAP_MAP_DIRECT |
637 BDI_CAP_READ_MAP |
638 BDI_CAP_WRITE_MAP;
639 break;
640
641 default:
642 return -EINVAL;
643 }
644 }
645
646 /* eliminate any capabilities that we can't support on this
647 * device */
648 if (!file->f_op->get_unmapped_area)
649 capabilities &= ~BDI_CAP_MAP_DIRECT;
650 if (!file->f_op->read)
651 capabilities &= ~BDI_CAP_MAP_COPY;
652
653 if (flags & MAP_SHARED) {
654 /* do checks for writing, appending and locking */
655 if ((prot & PROT_WRITE) &&
656 !(file->f_mode & FMODE_WRITE))
657 return -EACCES;
658
Josef Sipeke9536ae2006-12-08 02:37:21 -0800659 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 (file->f_mode & FMODE_WRITE))
661 return -EACCES;
662
Josef Sipeke9536ae2006-12-08 02:37:21 -0800663 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 return -EAGAIN;
665
666 if (!(capabilities & BDI_CAP_MAP_DIRECT))
667 return -ENODEV;
668
669 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
670 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
671 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
672 ) {
673 printk("MAP_SHARED not completely supported on !MMU\n");
674 return -EINVAL;
675 }
676
677 /* we mustn't privatise shared mappings */
678 capabilities &= ~BDI_CAP_MAP_COPY;
679 }
680 else {
681 /* we're going to read the file into private memory we
682 * allocate */
683 if (!(capabilities & BDI_CAP_MAP_COPY))
684 return -ENODEV;
685
686 /* we don't permit a private writable mapping to be
687 * shared with the backing device */
688 if (prot & PROT_WRITE)
689 capabilities &= ~BDI_CAP_MAP_DIRECT;
690 }
691
692 /* handle executable mappings and implied executable
693 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800694 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 if (prot & PROT_EXEC)
696 return -EPERM;
697 }
698 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
699 /* handle implication of PROT_EXEC by PROT_READ */
700 if (current->personality & READ_IMPLIES_EXEC) {
701 if (capabilities & BDI_CAP_EXEC_MAP)
702 prot |= PROT_EXEC;
703 }
704 }
705 else if ((prot & PROT_READ) &&
706 (prot & PROT_EXEC) &&
707 !(capabilities & BDI_CAP_EXEC_MAP)
708 ) {
709 /* backing file is not executable, try to copy */
710 capabilities &= ~BDI_CAP_MAP_DIRECT;
711 }
712 }
713 else {
714 /* anonymous mappings are always memory backed and can be
715 * privately mapped
716 */
717 capabilities = BDI_CAP_MAP_COPY;
718
719 /* handle PROT_EXEC implication by PROT_READ */
720 if ((prot & PROT_READ) &&
721 (current->personality & READ_IMPLIES_EXEC))
722 prot |= PROT_EXEC;
723 }
724
725 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400726 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 if (ret < 0)
728 return ret;
729
730 /* looks okay */
731 *_capabilities = capabilities;
732 return 0;
733}
734
735/*
736 * we've determined that we can make the mapping, now translate what we
737 * now know into VMA flags
738 */
739static unsigned long determine_vm_flags(struct file *file,
740 unsigned long prot,
741 unsigned long flags,
742 unsigned long capabilities)
743{
744 unsigned long vm_flags;
745
746 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
747 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
748 /* vm_flags |= mm->def_flags; */
749
750 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
751 /* attempt to share read-only copies of mapped file chunks */
752 if (file && !(prot & PROT_WRITE))
753 vm_flags |= VM_MAYSHARE;
754 }
755 else {
756 /* overlay a shareable mapping on the backing device or inode
757 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
758 * romfs/cramfs */
759 if (flags & MAP_SHARED)
760 vm_flags |= VM_MAYSHARE | VM_SHARED;
761 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
762 vm_flags |= VM_MAYSHARE;
763 }
764
765 /* refuse to let anyone share private mappings with this process if
766 * it's being traced - otherwise breakpoints set in it may interfere
767 * with another untraced process
768 */
Roland McGrathfa8e26c2008-07-25 19:45:50 -0700769 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 vm_flags &= ~VM_MAYSHARE;
771
772 return vm_flags;
773}
774
775/*
776 * set up a shared mapping on a file
777 */
778static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
779{
780 int ret;
781
782 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
783 if (ret != -ENOSYS)
784 return ret;
785
786 /* getting an ENOSYS error indicates that direct mmap isn't
787 * possible (as opposed to tried but failed) so we'll fall
788 * through to making a private copy of the data and mapping
789 * that if we can */
790 return -ENODEV;
791}
792
793/*
794 * set up a private mapping or an anonymous shared mapping
795 */
796static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
797{
798 void *base;
799 int ret;
800
801 /* invoke the file's mapping function so that it can keep track of
802 * shared mappings on devices or memory
803 * - VM_MAYSHARE will be set if it may attempt to share
804 */
805 if (vma->vm_file) {
806 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
807 if (ret != -ENOSYS) {
808 /* shouldn't return success if we're not sharing */
809 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
810 return ret; /* success or a real error */
811 }
812
813 /* getting an ENOSYS error indicates that direct mmap isn't
814 * possible (as opposed to tried but failed) so we'll try to
815 * make a private copy of the data and map that instead */
816 }
817
818 /* allocate some memory to hold the mapping
819 * - note that this may not return a page-aligned address if the object
820 * we're allocating is smaller than a page
821 */
Nick Piggin84097512006-03-22 00:08:34 -0800822 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 if (!base)
824 goto enomem;
825
826 vma->vm_start = (unsigned long) base;
827 vma->vm_end = vma->vm_start + len;
828 vma->vm_flags |= VM_MAPPED_COPY;
829
830#ifdef WARN_ON_SLACK
831 if (len + WARN_ON_SLACK <= kobjsize(result))
832 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
833 len, current->pid, kobjsize(result) - len);
834#endif
835
836 if (vma->vm_file) {
837 /* read the contents of a file into the copy */
838 mm_segment_t old_fs;
839 loff_t fpos;
840
841 fpos = vma->vm_pgoff;
842 fpos <<= PAGE_SHIFT;
843
844 old_fs = get_fs();
845 set_fs(KERNEL_DS);
846 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
847 set_fs(old_fs);
848
849 if (ret < 0)
850 goto error_free;
851
852 /* clear the last little bit */
853 if (ret < len)
854 memset(base + ret, 0, len - ret);
855
856 } else {
857 /* if it's an anonymous mapping, then just clear it */
858 memset(base, 0, len);
859 }
860
861 return 0;
862
863error_free:
864 kfree(base);
865 vma->vm_start = 0;
866 return ret;
867
868enomem:
869 printk("Allocation of length %lu from process %d failed\n",
870 len, current->pid);
871 show_free_areas();
872 return -ENOMEM;
873}
874
875/*
876 * handle mapping creation for uClinux
877 */
878unsigned long do_mmap_pgoff(struct file *file,
879 unsigned long addr,
880 unsigned long len,
881 unsigned long prot,
882 unsigned long flags,
883 unsigned long pgoff)
884{
885 struct vm_list_struct *vml = NULL;
886 struct vm_area_struct *vma = NULL;
887 struct rb_node *rb;
888 unsigned long capabilities, vm_flags;
889 void *result;
890 int ret;
891
Eric Paris7cd94142007-11-26 18:47:40 -0500892 if (!(flags & MAP_FIXED))
893 addr = round_hint_to_min(addr);
894
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 /* decide whether we should attempt the mapping, and if so what sort of
896 * mapping */
897 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
898 &capabilities);
899 if (ret < 0)
900 return ret;
901
902 /* we've determined that we can make the mapping, now translate what we
903 * now know into VMA flags */
904 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
905
906 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800907 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 if (!vml)
909 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910
911 down_write(&nommu_vma_sem);
912
913 /* if we want to share, we need to check for VMAs created by other
914 * mmap() calls that overlap with our proposed mapping
915 * - we can only share with an exact match on most regular files
916 * - shared mappings on character devices and memory backed files are
917 * permitted to overlap inexactly as far as we are concerned for in
918 * these cases, sharing is handled in the driver or filesystem rather
919 * than here
920 */
921 if (vm_flags & VM_MAYSHARE) {
922 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
923 unsigned long vmpglen;
924
David Howells165b2392007-03-22 00:11:24 -0800925 /* suppress VMA sharing for shared regions */
926 if (vm_flags & VM_SHARED &&
927 capabilities & BDI_CAP_MAP_DIRECT)
928 goto dont_share_VMAs;
929
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
931 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
932
933 if (!(vma->vm_flags & VM_MAYSHARE))
934 continue;
935
936 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800937 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 continue;
939
940 if (vma->vm_pgoff >= pgoff + pglen)
941 continue;
942
943 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
944 vmpglen >>= PAGE_SHIFT;
945 if (pgoff >= vma->vm_pgoff + vmpglen)
946 continue;
947
948 /* handle inexactly overlapping matches between mappings */
949 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
950 if (!(capabilities & BDI_CAP_MAP_DIRECT))
951 goto sharing_violation;
952 continue;
953 }
954
955 /* we've found a VMA we can share */
956 atomic_inc(&vma->vm_usage);
957
958 vml->vma = vma;
959 result = (void *) vma->vm_start;
960 goto shared;
961 }
962
David Howells165b2392007-03-22 00:11:24 -0800963 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 vma = NULL;
965
966 /* obtain the address at which to make a shared mapping
967 * - this is the hook for quasi-memory character devices to
968 * tell us the location of a shared mapping
969 */
970 if (file && file->f_op->get_unmapped_area) {
971 addr = file->f_op->get_unmapped_area(file, addr, len,
972 pgoff, flags);
973 if (IS_ERR((void *) addr)) {
974 ret = addr;
975 if (ret != (unsigned long) -ENOSYS)
976 goto error;
977
978 /* the driver refused to tell us where to site
979 * the mapping so we'll have to attempt to copy
980 * it */
981 ret = (unsigned long) -ENODEV;
982 if (!(capabilities & BDI_CAP_MAP_COPY))
983 goto error;
984
985 capabilities &= ~BDI_CAP_MAP_DIRECT;
986 }
987 }
988 }
989
990 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800991 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 if (!vma)
993 goto error_getting_vma;
994
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 INIT_LIST_HEAD(&vma->anon_vma_node);
996 atomic_set(&vma->vm_usage, 1);
Matt Helsley925d1c42008-04-29 01:01:36 -0700997 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 get_file(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700999 if (vm_flags & VM_EXECUTABLE) {
1000 added_exe_file_vma(current->mm);
1001 vma->vm_mm = current->mm;
1002 }
1003 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 vma->vm_file = file;
1005 vma->vm_flags = vm_flags;
1006 vma->vm_start = addr;
1007 vma->vm_end = addr + len;
1008 vma->vm_pgoff = pgoff;
1009
1010 vml->vma = vma;
1011
1012 /* set up the mapping */
1013 if (file && vma->vm_flags & VM_SHARED)
1014 ret = do_mmap_shared_file(vma, len);
1015 else
1016 ret = do_mmap_private(vma, len);
1017 if (ret < 0)
1018 goto error;
1019
1020 /* okay... we have a mapping; now we have to register it */
1021 result = (void *) vma->vm_start;
1022
1023 if (vma->vm_flags & VM_MAPPED_COPY) {
1024 realalloc += kobjsize(result);
1025 askedalloc += len;
1026 }
1027
1028 realalloc += kobjsize(vma);
1029 askedalloc += sizeof(*vma);
1030
1031 current->mm->total_vm += len >> PAGE_SHIFT;
1032
1033 add_nommu_vma(vma);
1034
1035 shared:
1036 realalloc += kobjsize(vml);
1037 askedalloc += sizeof(*vml);
1038
David Howells30340972006-09-27 01:50:20 -07001039 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040
1041 up_write(&nommu_vma_sem);
1042
1043 if (prot & PROT_EXEC)
1044 flush_icache_range((unsigned long) result,
1045 (unsigned long) result + len);
1046
1047#ifdef DEBUG
1048 printk("do_mmap:\n");
1049 show_process_blocks();
1050#endif
1051
1052 return (unsigned long) result;
1053
1054 error:
1055 up_write(&nommu_vma_sem);
1056 kfree(vml);
1057 if (vma) {
Matt Helsley925d1c42008-04-29 01:01:36 -07001058 if (vma->vm_file) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -07001059 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001060 if (vma->vm_flags & VM_EXECUTABLE)
1061 removed_exe_file_vma(vma->vm_mm);
1062 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063 kfree(vma);
1064 }
1065 return ret;
1066
1067 sharing_violation:
1068 up_write(&nommu_vma_sem);
1069 printk("Attempt to share mismatched mappings\n");
1070 kfree(vml);
1071 return -EINVAL;
1072
1073 error_getting_vma:
1074 up_write(&nommu_vma_sem);
1075 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001076 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 len, current->pid);
1078 show_free_areas();
1079 return -ENOMEM;
1080
1081 error_getting_vml:
1082 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1083 len, current->pid);
1084 show_free_areas();
1085 return -ENOMEM;
1086}
Paul Mundtb5073172007-07-21 04:37:25 -07001087EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088
1089/*
1090 * handle mapping disposal for uClinux
1091 */
Matt Helsley925d1c42008-04-29 01:01:36 -07001092static void put_vma(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093{
1094 if (vma) {
1095 down_write(&nommu_vma_sem);
1096
1097 if (atomic_dec_and_test(&vma->vm_usage)) {
1098 delete_nommu_vma(vma);
1099
1100 if (vma->vm_ops && vma->vm_ops->close)
1101 vma->vm_ops->close(vma);
1102
1103 /* IO memory and memory shared directly out of the pagecache from
1104 * ramfs/tmpfs mustn't be released here */
1105 if (vma->vm_flags & VM_MAPPED_COPY) {
1106 realalloc -= kobjsize((void *) vma->vm_start);
1107 askedalloc -= vma->vm_end - vma->vm_start;
1108 kfree((void *) vma->vm_start);
1109 }
1110
1111 realalloc -= kobjsize(vma);
1112 askedalloc -= sizeof(*vma);
1113
Matt Helsley925d1c42008-04-29 01:01:36 -07001114 if (vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001116 if (vma->vm_flags & VM_EXECUTABLE)
1117 removed_exe_file_vma(mm);
1118 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 kfree(vma);
1120 }
1121
1122 up_write(&nommu_vma_sem);
1123 }
1124}
1125
David Howells30340972006-09-27 01:50:20 -07001126/*
1127 * release a mapping
1128 * - under NOMMU conditions the parameters must match exactly to the mapping to
1129 * be removed
1130 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1132{
1133 struct vm_list_struct *vml, **parent;
1134 unsigned long end = addr + len;
1135
1136#ifdef DEBUG
1137 printk("do_munmap:\n");
1138#endif
1139
David Howells30340972006-09-27 01:50:20 -07001140 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1141 if ((*parent)->vma->vm_start > addr)
1142 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001144 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 goto found;
David Howells30340972006-09-27 01:50:20 -07001146 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147
1148 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1149 current->pid, current->comm, (void *) addr);
1150 return -EINVAL;
1151
1152 found:
1153 vml = *parent;
1154
Matt Helsley925d1c42008-04-29 01:01:36 -07001155 put_vma(mm, vml->vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156
1157 *parent = vml->next;
1158 realalloc -= kobjsize(vml);
1159 askedalloc -= sizeof(*vml);
1160 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001161
1162 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 mm->total_vm -= len >> PAGE_SHIFT;
1164
1165#ifdef DEBUG
1166 show_process_blocks();
1167#endif
1168
1169 return 0;
1170}
Paul Mundtb5073172007-07-21 04:37:25 -07001171EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172
David Howells30340972006-09-27 01:50:20 -07001173asmlinkage long sys_munmap(unsigned long addr, size_t len)
1174{
1175 int ret;
1176 struct mm_struct *mm = current->mm;
1177
1178 down_write(&mm->mmap_sem);
1179 ret = do_munmap(mm, addr, len);
1180 up_write(&mm->mmap_sem);
1181 return ret;
1182}
1183
1184/*
1185 * Release all mappings
1186 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187void exit_mmap(struct mm_struct * mm)
1188{
1189 struct vm_list_struct *tmp;
1190
1191 if (mm) {
1192#ifdef DEBUG
1193 printk("Exit_mmap:\n");
1194#endif
1195
1196 mm->total_vm = 0;
1197
1198 while ((tmp = mm->context.vmlist)) {
1199 mm->context.vmlist = tmp->next;
Matt Helsley925d1c42008-04-29 01:01:36 -07001200 put_vma(mm, tmp->vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201
1202 realalloc -= kobjsize(tmp);
1203 askedalloc -= sizeof(*tmp);
1204 kfree(tmp);
1205 }
1206
1207#ifdef DEBUG
1208 show_process_blocks();
1209#endif
1210 }
1211}
1212
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213unsigned long do_brk(unsigned long addr, unsigned long len)
1214{
1215 return -ENOMEM;
1216}
1217
1218/*
David Howells6fa5f802006-09-27 01:50:21 -07001219 * expand (or shrink) an existing mapping, potentially moving it at the same
1220 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 *
David Howells6fa5f802006-09-27 01:50:21 -07001222 * under NOMMU conditions, we only permit changing a mapping's size, and only
1223 * as long as it stays within the hole allocated by the kmalloc() call in
1224 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 *
David Howells6fa5f802006-09-27 01:50:21 -07001226 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 */
1228unsigned long do_mremap(unsigned long addr,
1229 unsigned long old_len, unsigned long new_len,
1230 unsigned long flags, unsigned long new_addr)
1231{
David Howells6fa5f802006-09-27 01:50:21 -07001232 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
1234 /* insanity checks first */
1235 if (new_len == 0)
1236 return (unsigned long) -EINVAL;
1237
1238 if (flags & MREMAP_FIXED && new_addr != addr)
1239 return (unsigned long) -EINVAL;
1240
David Howells6fa5f802006-09-27 01:50:21 -07001241 vma = find_vma_exact(current->mm, addr);
1242 if (!vma)
1243 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244
David Howells6fa5f802006-09-27 01:50:21 -07001245 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 return (unsigned long) -EFAULT;
1247
David Howells6fa5f802006-09-27 01:50:21 -07001248 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 return (unsigned long) -EPERM;
1250
1251 if (new_len > kobjsize((void *) addr))
1252 return (unsigned long) -ENOMEM;
1253
1254 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001255 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256
1257 askedalloc -= old_len;
1258 askedalloc += new_len;
1259
David Howells6fa5f802006-09-27 01:50:21 -07001260 return vma->vm_start;
1261}
Paul Mundtb5073172007-07-21 04:37:25 -07001262EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001263
1264asmlinkage unsigned long sys_mremap(unsigned long addr,
1265 unsigned long old_len, unsigned long new_len,
1266 unsigned long flags, unsigned long new_addr)
1267{
1268 unsigned long ret;
1269
1270 down_write(&current->mm->mmap_sem);
1271 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1272 up_write(&current->mm->mmap_sem);
1273 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274}
1275
Linus Torvalds6aab3412005-11-28 14:34:23 -08001276struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001277 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278{
1279 return NULL;
1280}
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1283 unsigned long to, unsigned long size, pgprot_t prot)
1284{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001285 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1286 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287}
Luke Yang22c4af42006-07-14 00:24:09 -07001288EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289
Paul Mundtf905bc42008-02-04 22:29:59 -08001290int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1291 unsigned long pgoff)
1292{
1293 unsigned int size = vma->vm_end - vma->vm_start;
1294
1295 if (!(vma->vm_flags & VM_USERMAP))
1296 return -EINVAL;
1297
1298 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1299 vma->vm_end = vma->vm_start + size;
1300
1301 return 0;
1302}
1303EXPORT_SYMBOL(remap_vmalloc_range);
1304
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1306{
1307}
1308
1309unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1310 unsigned long len, unsigned long pgoff, unsigned long flags)
1311{
1312 return -ENOMEM;
1313}
1314
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001315void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316{
1317}
1318
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319void unmap_mapping_range(struct address_space *mapping,
1320 loff_t const holebegin, loff_t const holelen,
1321 int even_cows)
1322{
1323}
Luke Yang22c4af42006-07-14 00:24:09 -07001324EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325
1326/*
David Howellsd56e03c2007-03-22 00:11:23 -08001327 * ask for an unmapped area at which to create a mapping on a file
1328 */
1329unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1330 unsigned long len, unsigned long pgoff,
1331 unsigned long flags)
1332{
1333 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1334 unsigned long, unsigned long);
1335
1336 get_area = current->mm->get_unmapped_area;
1337 if (file && file->f_op && file->f_op->get_unmapped_area)
1338 get_area = file->f_op->get_unmapped_area;
1339
1340 if (!get_area)
1341 return -ENOSYS;
1342
1343 return get_area(file, addr, len, pgoff, flags);
1344}
David Howellsd56e03c2007-03-22 00:11:23 -08001345EXPORT_SYMBOL(get_unmapped_area);
1346
1347/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 * Check that a process has enough memory to allocate a new virtual
1349 * mapping. 0 means there is enough memory for the allocation to
1350 * succeed and -ENOMEM implies there is not.
1351 *
1352 * We currently support three overcommit policies, which are set via the
1353 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1354 *
1355 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1356 * Additional code 2002 Jul 20 by Robert Love.
1357 *
1358 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1359 *
1360 * Note this is a helper function intended to be used by LSMs which
1361 * wish to use this logic.
1362 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001363int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364{
1365 unsigned long free, allowed;
1366
1367 vm_acct_memory(pages);
1368
1369 /*
1370 * Sometimes we want to use more memory than we have
1371 */
1372 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1373 return 0;
1374
1375 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1376 unsigned long n;
1377
Christoph Lameter347ce432006-06-30 01:55:35 -07001378 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 free += nr_swap_pages;
1380
1381 /*
1382 * Any slabs which are created with the
1383 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1384 * which are reclaimable, under pressure. The dentry
1385 * cache and most inode caches should fall into this
1386 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001387 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388
1389 /*
1390 * Leave the last 3% for root
1391 */
1392 if (!cap_sys_admin)
1393 free -= free / 32;
1394
1395 if (free > pages)
1396 return 0;
1397
1398 /*
1399 * nr_free_pages() is very expensive on large systems,
1400 * only call if we're about to fail.
1401 */
1402 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001403
1404 /*
1405 * Leave reserved pages. The pages are not for anonymous pages.
1406 */
1407 if (n <= totalreserve_pages)
1408 goto error;
1409 else
1410 n -= totalreserve_pages;
1411
1412 /*
1413 * Leave the last 3% for root
1414 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 if (!cap_sys_admin)
1416 n -= n / 32;
1417 free += n;
1418
1419 if (free > pages)
1420 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001421
1422 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 }
1424
1425 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1426 /*
1427 * Leave the last 3% for root
1428 */
1429 if (!cap_sys_admin)
1430 allowed -= allowed / 32;
1431 allowed += total_swap_pages;
1432
1433 /* Don't let a single process grow too big:
1434 leave 3% of the size of this process for other processes */
1435 allowed -= current->mm->total_vm / 32;
1436
Simon Derr2f60f8d2005-08-04 19:52:03 -07001437 /*
1438 * cast `allowed' as a signed long because vm_committed_space
1439 * sometimes has a negative value
1440 */
Alan Cox80119ef2008-05-23 13:04:31 -07001441 if (atomic_long_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001443error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444 vm_unacct_memory(pages);
1445
1446 return -ENOMEM;
1447}
1448
1449int in_gate_area_no_task(unsigned long addr)
1450{
1451 return 0;
1452}
David Howellsb0e15192006-01-06 00:11:42 -08001453
Nick Piggind0217ac2007-07-19 01:47:03 -07001454int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001455{
1456 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001457 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001458}
Paul Mundtb5073172007-07-21 04:37:25 -07001459EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001460
1461/*
1462 * Access another process' address space.
1463 * - source/target buffer must be kernel space
1464 */
1465int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1466{
David Howells0ec76a12006-09-27 01:50:15 -07001467 struct vm_area_struct *vma;
1468 struct mm_struct *mm;
1469
1470 if (addr + len < addr)
1471 return 0;
1472
1473 mm = get_task_mm(tsk);
1474 if (!mm)
1475 return 0;
1476
1477 down_read(&mm->mmap_sem);
1478
1479 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001480 vma = find_vma(mm, addr);
1481 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001482 /* don't overrun this mapping */
1483 if (addr + len >= vma->vm_end)
1484 len = vma->vm_end - addr;
1485
1486 /* only read or write mappings where it is permitted */
David Howellsd00c7b92006-09-27 01:50:19 -07001487 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001488 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b92006-09-27 01:50:19 -07001489 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001490 len -= copy_from_user(buf, (void *) addr, len);
1491 else
1492 len = 0;
1493 } else {
1494 len = 0;
1495 }
1496
1497 up_read(&mm->mmap_sem);
1498 mmput(mm);
1499 return len;
1500}