blob: ef8c62cec697a06495b13f2658aff4e30000065c [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>
25#include <linux/ptrace.h>
26#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;
42atomic_t vm_committed_space = ATOMIC_INIT(0);
43int 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 */
112 if (!objp || (unsigned long)objp >= memory_end || !((page = virt_to_page(objp))))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 return 0;
114
115 if (PageSlab(page))
116 return ksize(objp);
117
118 BUG_ON(page->index < 0);
119 BUG_ON(page->index >= MAX_ORDER);
120
121 return (PAGE_SIZE << page->index);
122}
123
124/*
David Howells7b4d5b82006-09-27 01:50:18 -0700125 * get a list of pages in an address range belonging to the specified process
126 * and indicate the VMA that covers each page
127 * - this is potentially dodgy as we may end incrementing the page count of a
128 * slab page or a secondary page from a compound page
129 * - don't permit access to VMAs that don't support it, such as I/O mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 */
131int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
132 unsigned long start, int len, int write, int force,
133 struct page **pages, struct vm_area_struct **vmas)
134{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700135 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700136 unsigned long vm_flags;
137 int i;
138
139 /* calculate required read or write permissions.
140 * - if 'force' is set, we only require the "MAY" flags.
141 */
142 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
143 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 for (i = 0; i < len; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700146 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700147 if (!vma)
148 goto finish_or_fault;
149
150 /* protect what we can, including chardevs */
151 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
152 !(vm_flags & vma->vm_flags))
153 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 if (pages) {
156 pages[i] = virt_to_page(start);
157 if (pages[i])
158 page_cache_get(pages[i]);
159 }
160 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700161 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 start += PAGE_SIZE;
163 }
David Howells7b4d5b82006-09-27 01:50:18 -0700164
165 return i;
166
167finish_or_fault:
168 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000170EXPORT_SYMBOL(get_user_pages);
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172DEFINE_RWLOCK(vmlist_lock);
173struct vm_struct *vmlist;
174
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800175void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
177 kfree(addr);
178}
Paul Mundtb5073172007-07-21 04:37:25 -0700179EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
Al Virodd0fc662005-10-07 07:46:04 +0100181void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200184 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
185 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 */
Nick Piggin84097512006-03-22 00:08:34 -0800187 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188}
Paul Mundtb5073172007-07-21 04:37:25 -0700189EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
Paul Mundtf905bc42008-02-04 22:29:59 -0800191void *vmalloc_user(unsigned long size)
192{
193 void *ret;
194
195 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
196 PAGE_KERNEL);
197 if (ret) {
198 struct vm_area_struct *vma;
199
200 down_write(&current->mm->mmap_sem);
201 vma = find_vma(current->mm, (unsigned long)ret);
202 if (vma)
203 vma->vm_flags |= VM_USERMAP;
204 up_write(&current->mm->mmap_sem);
205 }
206
207 return ret;
208}
209EXPORT_SYMBOL(vmalloc_user);
210
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800211struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
213 return virt_to_page(addr);
214}
Paul Mundtb5073172007-07-21 04:37:25 -0700215EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800217unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
219 return page_to_pfn(virt_to_page(addr));
220}
Paul Mundtb5073172007-07-21 04:37:25 -0700221EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
223long vread(char *buf, char *addr, unsigned long count)
224{
225 memcpy(buf, addr, count);
226 return count;
227}
228
229long vwrite(char *buf, char *addr, unsigned long count)
230{
231 /* Don't allow overflow */
232 if ((unsigned long) addr + count < count)
233 count = -(unsigned long) addr;
234
235 memcpy(addr, buf, count);
236 return(count);
237}
238
239/*
240 * vmalloc - allocate virtually continguos memory
241 *
242 * @size: allocation size
243 *
244 * Allocate enough pages to cover @size from the page level
245 * allocator and map them into continguos kernel virtual space.
246 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200247 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 * use __vmalloc() instead.
249 */
250void *vmalloc(unsigned long size)
251{
252 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
253}
Andrew Mortonf6138882006-02-28 16:59:18 -0800254EXPORT_SYMBOL(vmalloc);
255
256void *vmalloc_node(unsigned long size, int node)
257{
258 return vmalloc(size);
259}
260EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
Paul Mundtb5073172007-07-21 04:37:25 -0700262/**
263 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 * @size: allocation size
265 *
266 * Allocate enough 32bit PA addressable pages to cover @size from the
267 * page level allocator and map them into continguos kernel virtual space.
268 */
269void *vmalloc_32(unsigned long size)
270{
271 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
272}
Paul Mundtb5073172007-07-21 04:37:25 -0700273EXPORT_SYMBOL(vmalloc_32);
274
275/**
276 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
277 * @size: allocation size
278 *
279 * The resulting memory area is 32bit addressable and zeroed so it can be
280 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800281 *
282 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
283 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700284 */
285void *vmalloc_32_user(unsigned long size)
286{
Paul Mundtf905bc42008-02-04 22:29:59 -0800287 /*
288 * We'll have to sort out the ZONE_DMA bits for 64-bit,
289 * but for now this can simply use vmalloc_user() directly.
290 */
291 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700292}
293EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
295void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
296{
297 BUG();
298 return NULL;
299}
Paul Mundtb5073172007-07-21 04:37:25 -0700300EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800302void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
304 BUG();
305}
Paul Mundtb5073172007-07-21 04:37:25 -0700306EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
308/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700309 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
310 * have one.
311 */
312void __attribute__((weak)) vmalloc_sync_all(void)
313{
314}
315
Paul Mundtb5073172007-07-21 04:37:25 -0700316int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
317 struct page *page)
318{
319 return -EINVAL;
320}
321EXPORT_SYMBOL(vm_insert_page);
322
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700323/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 * sys_brk() for the most part doesn't need the global kernel
325 * lock, except when an application is doing something nasty
326 * like trying to un-brk an area that has already been mapped
327 * to a regular file. in this case, the unmapping will need
328 * to invoke file system routines that need the global lock.
329 */
330asmlinkage unsigned long sys_brk(unsigned long brk)
331{
332 struct mm_struct *mm = current->mm;
333
334 if (brk < mm->start_brk || brk > mm->context.end_brk)
335 return mm->brk;
336
337 if (mm->brk == brk)
338 return mm->brk;
339
340 /*
341 * Always allow shrinking brk
342 */
343 if (brk <= mm->brk) {
344 mm->brk = brk;
345 return brk;
346 }
347
348 /*
349 * Ok, looks good - let it rip.
350 */
351 return mm->brk = brk;
352}
353
354#ifdef DEBUG
355static void show_process_blocks(void)
356{
357 struct vm_list_struct *vml;
358
359 printk("Process blocks %d:", current->pid);
360
361 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
362 printk(" %p: %p", vml, vml->vma);
363 if (vml->vma)
364 printk(" (%d @%lx #%d)",
365 kobjsize((void *) vml->vma->vm_start),
366 vml->vma->vm_start,
367 atomic_read(&vml->vma->vm_usage));
368 printk(vml->next ? " ->" : ".\n");
369 }
370}
371#endif /* DEBUG */
372
David Howells30340972006-09-27 01:50:20 -0700373/*
374 * add a VMA into a process's mm_struct in the appropriate place in the list
375 * - should be called with mm->mmap_sem held writelocked
376 */
377static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
378{
379 struct vm_list_struct **ppv;
380
381 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
382 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
383 break;
384
385 vml->next = *ppv;
386 *ppv = vml;
387}
388
389/*
390 * look up the first VMA in which addr resides, NULL if none
391 * - should be called with mm->mmap_sem at least held readlocked
392 */
393struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
394{
395 struct vm_list_struct *loop, *vml;
396
397 /* search the vm_start ordered list */
398 vml = NULL;
399 for (loop = mm->context.vmlist; loop; loop = loop->next) {
400 if (loop->vma->vm_start > addr)
401 break;
402 vml = loop;
403 }
404
405 if (vml && vml->vma->vm_end > addr)
406 return vml->vma;
407
408 return NULL;
409}
410EXPORT_SYMBOL(find_vma);
411
412/*
David Howells930e6522006-09-27 01:50:22 -0700413 * find a VMA
414 * - we don't extend stack VMAs under NOMMU conditions
415 */
416struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
417{
418 return find_vma(mm, addr);
419}
420
Greg Ungerer57c8f632007-07-15 23:38:28 -0700421int expand_stack(struct vm_area_struct *vma, unsigned long address)
422{
423 return -ENOMEM;
424}
425
David Howells930e6522006-09-27 01:50:22 -0700426/*
David Howells6fa5f802006-09-27 01:50:21 -0700427 * look up the first VMA exactly that exactly matches addr
428 * - should be called with mm->mmap_sem at least held readlocked
429 */
430static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
431 unsigned long addr)
432{
433 struct vm_list_struct *vml;
434
435 /* search the vm_start ordered list */
436 for (vml = mm->context.vmlist; vml; vml = vml->next) {
437 if (vml->vma->vm_start == addr)
438 return vml->vma;
439 if (vml->vma->vm_start > addr)
440 break;
441 }
442
443 return NULL;
444}
445
446/*
David Howells30340972006-09-27 01:50:20 -0700447 * find a VMA in the global tree
448 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
450{
451 struct vm_area_struct *vma;
452 struct rb_node *n = nommu_vma_tree.rb_node;
453
454 while (n) {
455 vma = rb_entry(n, struct vm_area_struct, vm_rb);
456
457 if (start < vma->vm_start)
458 n = n->rb_left;
459 else if (start > vma->vm_start)
460 n = n->rb_right;
461 else
462 return vma;
463 }
464
465 return NULL;
466}
467
David Howells30340972006-09-27 01:50:20 -0700468/*
469 * add a VMA in the global tree
470 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471static void add_nommu_vma(struct vm_area_struct *vma)
472{
473 struct vm_area_struct *pvma;
474 struct address_space *mapping;
475 struct rb_node **p = &nommu_vma_tree.rb_node;
476 struct rb_node *parent = NULL;
477
478 /* add the VMA to the mapping */
479 if (vma->vm_file) {
480 mapping = vma->vm_file->f_mapping;
481
482 flush_dcache_mmap_lock(mapping);
483 vma_prio_tree_insert(vma, &mapping->i_mmap);
484 flush_dcache_mmap_unlock(mapping);
485 }
486
487 /* add the VMA to the master list */
488 while (*p) {
489 parent = *p;
490 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
491
492 if (vma->vm_start < pvma->vm_start) {
493 p = &(*p)->rb_left;
494 }
495 else if (vma->vm_start > pvma->vm_start) {
496 p = &(*p)->rb_right;
497 }
498 else {
499 /* mappings are at the same address - this can only
500 * happen for shared-mem chardevs and shared file
501 * mappings backed by ramfs/tmpfs */
502 BUG_ON(!(pvma->vm_flags & VM_SHARED));
503
504 if (vma < pvma)
505 p = &(*p)->rb_left;
506 else if (vma > pvma)
507 p = &(*p)->rb_right;
508 else
509 BUG();
510 }
511 }
512
513 rb_link_node(&vma->vm_rb, parent, p);
514 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
515}
516
David Howells30340972006-09-27 01:50:20 -0700517/*
518 * delete a VMA from the global list
519 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520static void delete_nommu_vma(struct vm_area_struct *vma)
521{
522 struct address_space *mapping;
523
524 /* remove the VMA from the mapping */
525 if (vma->vm_file) {
526 mapping = vma->vm_file->f_mapping;
527
528 flush_dcache_mmap_lock(mapping);
529 vma_prio_tree_remove(vma, &mapping->i_mmap);
530 flush_dcache_mmap_unlock(mapping);
531 }
532
533 /* remove from the master list */
534 rb_erase(&vma->vm_rb, &nommu_vma_tree);
535}
536
537/*
538 * determine whether a mapping should be permitted and, if so, what sort of
539 * mapping we're capable of supporting
540 */
541static int validate_mmap_request(struct file *file,
542 unsigned long addr,
543 unsigned long len,
544 unsigned long prot,
545 unsigned long flags,
546 unsigned long pgoff,
547 unsigned long *_capabilities)
548{
549 unsigned long capabilities;
550 unsigned long reqprot = prot;
551 int ret;
552
553 /* do the simple checks first */
554 if (flags & MAP_FIXED || addr) {
555 printk(KERN_DEBUG
556 "%d: Can't do fixed-address/overlay mmap of RAM\n",
557 current->pid);
558 return -EINVAL;
559 }
560
561 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
562 (flags & MAP_TYPE) != MAP_SHARED)
563 return -EINVAL;
564
Mike Frysingerf81cff02006-12-06 12:02:59 +1000565 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 return -EINVAL;
567
Mike Frysingerf81cff02006-12-06 12:02:59 +1000568 /* Careful about overflows.. */
569 len = PAGE_ALIGN(len);
570 if (!len || len > TASK_SIZE)
571 return -ENOMEM;
572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 /* offset overflow? */
574 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000575 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576
577 if (file) {
578 /* validate file mapping requests */
579 struct address_space *mapping;
580
581 /* files must support mmap */
582 if (!file->f_op || !file->f_op->mmap)
583 return -ENODEV;
584
585 /* work out if what we've got could possibly be shared
586 * - we support chardevs that provide their own "memory"
587 * - we support files/blockdevs that are memory backed
588 */
589 mapping = file->f_mapping;
590 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800591 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592
593 capabilities = 0;
594 if (mapping && mapping->backing_dev_info)
595 capabilities = mapping->backing_dev_info->capabilities;
596
597 if (!capabilities) {
598 /* no explicit capabilities set, so assume some
599 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800600 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 case S_IFREG:
602 case S_IFBLK:
603 capabilities = BDI_CAP_MAP_COPY;
604 break;
605
606 case S_IFCHR:
607 capabilities =
608 BDI_CAP_MAP_DIRECT |
609 BDI_CAP_READ_MAP |
610 BDI_CAP_WRITE_MAP;
611 break;
612
613 default:
614 return -EINVAL;
615 }
616 }
617
618 /* eliminate any capabilities that we can't support on this
619 * device */
620 if (!file->f_op->get_unmapped_area)
621 capabilities &= ~BDI_CAP_MAP_DIRECT;
622 if (!file->f_op->read)
623 capabilities &= ~BDI_CAP_MAP_COPY;
624
625 if (flags & MAP_SHARED) {
626 /* do checks for writing, appending and locking */
627 if ((prot & PROT_WRITE) &&
628 !(file->f_mode & FMODE_WRITE))
629 return -EACCES;
630
Josef Sipeke9536ae2006-12-08 02:37:21 -0800631 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 (file->f_mode & FMODE_WRITE))
633 return -EACCES;
634
Josef Sipeke9536ae2006-12-08 02:37:21 -0800635 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 return -EAGAIN;
637
638 if (!(capabilities & BDI_CAP_MAP_DIRECT))
639 return -ENODEV;
640
641 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
642 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
643 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
644 ) {
645 printk("MAP_SHARED not completely supported on !MMU\n");
646 return -EINVAL;
647 }
648
649 /* we mustn't privatise shared mappings */
650 capabilities &= ~BDI_CAP_MAP_COPY;
651 }
652 else {
653 /* we're going to read the file into private memory we
654 * allocate */
655 if (!(capabilities & BDI_CAP_MAP_COPY))
656 return -ENODEV;
657
658 /* we don't permit a private writable mapping to be
659 * shared with the backing device */
660 if (prot & PROT_WRITE)
661 capabilities &= ~BDI_CAP_MAP_DIRECT;
662 }
663
664 /* handle executable mappings and implied executable
665 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800666 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 if (prot & PROT_EXEC)
668 return -EPERM;
669 }
670 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
671 /* handle implication of PROT_EXEC by PROT_READ */
672 if (current->personality & READ_IMPLIES_EXEC) {
673 if (capabilities & BDI_CAP_EXEC_MAP)
674 prot |= PROT_EXEC;
675 }
676 }
677 else if ((prot & PROT_READ) &&
678 (prot & PROT_EXEC) &&
679 !(capabilities & BDI_CAP_EXEC_MAP)
680 ) {
681 /* backing file is not executable, try to copy */
682 capabilities &= ~BDI_CAP_MAP_DIRECT;
683 }
684 }
685 else {
686 /* anonymous mappings are always memory backed and can be
687 * privately mapped
688 */
689 capabilities = BDI_CAP_MAP_COPY;
690
691 /* handle PROT_EXEC implication by PROT_READ */
692 if ((prot & PROT_READ) &&
693 (current->personality & READ_IMPLIES_EXEC))
694 prot |= PROT_EXEC;
695 }
696
697 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400698 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 if (ret < 0)
700 return ret;
701
702 /* looks okay */
703 *_capabilities = capabilities;
704 return 0;
705}
706
707/*
708 * we've determined that we can make the mapping, now translate what we
709 * now know into VMA flags
710 */
711static unsigned long determine_vm_flags(struct file *file,
712 unsigned long prot,
713 unsigned long flags,
714 unsigned long capabilities)
715{
716 unsigned long vm_flags;
717
718 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
719 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
720 /* vm_flags |= mm->def_flags; */
721
722 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
723 /* attempt to share read-only copies of mapped file chunks */
724 if (file && !(prot & PROT_WRITE))
725 vm_flags |= VM_MAYSHARE;
726 }
727 else {
728 /* overlay a shareable mapping on the backing device or inode
729 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
730 * romfs/cramfs */
731 if (flags & MAP_SHARED)
732 vm_flags |= VM_MAYSHARE | VM_SHARED;
733 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
734 vm_flags |= VM_MAYSHARE;
735 }
736
737 /* refuse to let anyone share private mappings with this process if
738 * it's being traced - otherwise breakpoints set in it may interfere
739 * with another untraced process
740 */
741 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
742 vm_flags &= ~VM_MAYSHARE;
743
744 return vm_flags;
745}
746
747/*
748 * set up a shared mapping on a file
749 */
750static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
751{
752 int ret;
753
754 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
755 if (ret != -ENOSYS)
756 return ret;
757
758 /* getting an ENOSYS error indicates that direct mmap isn't
759 * possible (as opposed to tried but failed) so we'll fall
760 * through to making a private copy of the data and mapping
761 * that if we can */
762 return -ENODEV;
763}
764
765/*
766 * set up a private mapping or an anonymous shared mapping
767 */
768static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
769{
770 void *base;
771 int ret;
772
773 /* invoke the file's mapping function so that it can keep track of
774 * shared mappings on devices or memory
775 * - VM_MAYSHARE will be set if it may attempt to share
776 */
777 if (vma->vm_file) {
778 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
779 if (ret != -ENOSYS) {
780 /* shouldn't return success if we're not sharing */
781 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
782 return ret; /* success or a real error */
783 }
784
785 /* getting an ENOSYS error indicates that direct mmap isn't
786 * possible (as opposed to tried but failed) so we'll try to
787 * make a private copy of the data and map that instead */
788 }
789
790 /* allocate some memory to hold the mapping
791 * - note that this may not return a page-aligned address if the object
792 * we're allocating is smaller than a page
793 */
Nick Piggin84097512006-03-22 00:08:34 -0800794 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 if (!base)
796 goto enomem;
797
798 vma->vm_start = (unsigned long) base;
799 vma->vm_end = vma->vm_start + len;
800 vma->vm_flags |= VM_MAPPED_COPY;
801
802#ifdef WARN_ON_SLACK
803 if (len + WARN_ON_SLACK <= kobjsize(result))
804 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
805 len, current->pid, kobjsize(result) - len);
806#endif
807
808 if (vma->vm_file) {
809 /* read the contents of a file into the copy */
810 mm_segment_t old_fs;
811 loff_t fpos;
812
813 fpos = vma->vm_pgoff;
814 fpos <<= PAGE_SHIFT;
815
816 old_fs = get_fs();
817 set_fs(KERNEL_DS);
818 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
819 set_fs(old_fs);
820
821 if (ret < 0)
822 goto error_free;
823
824 /* clear the last little bit */
825 if (ret < len)
826 memset(base + ret, 0, len - ret);
827
828 } else {
829 /* if it's an anonymous mapping, then just clear it */
830 memset(base, 0, len);
831 }
832
833 return 0;
834
835error_free:
836 kfree(base);
837 vma->vm_start = 0;
838 return ret;
839
840enomem:
841 printk("Allocation of length %lu from process %d failed\n",
842 len, current->pid);
843 show_free_areas();
844 return -ENOMEM;
845}
846
847/*
848 * handle mapping creation for uClinux
849 */
850unsigned long do_mmap_pgoff(struct file *file,
851 unsigned long addr,
852 unsigned long len,
853 unsigned long prot,
854 unsigned long flags,
855 unsigned long pgoff)
856{
857 struct vm_list_struct *vml = NULL;
858 struct vm_area_struct *vma = NULL;
859 struct rb_node *rb;
860 unsigned long capabilities, vm_flags;
861 void *result;
862 int ret;
863
Eric Paris7cd94142007-11-26 18:47:40 -0500864 if (!(flags & MAP_FIXED))
865 addr = round_hint_to_min(addr);
866
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 /* decide whether we should attempt the mapping, and if so what sort of
868 * mapping */
869 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
870 &capabilities);
871 if (ret < 0)
872 return ret;
873
874 /* we've determined that we can make the mapping, now translate what we
875 * now know into VMA flags */
876 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
877
878 /* we're going to need to record the mapping if it works */
Burman Yan4668edc2006-12-06 20:38:51 -0800879 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 if (!vml)
881 goto error_getting_vml;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882
883 down_write(&nommu_vma_sem);
884
885 /* if we want to share, we need to check for VMAs created by other
886 * mmap() calls that overlap with our proposed mapping
887 * - we can only share with an exact match on most regular files
888 * - shared mappings on character devices and memory backed files are
889 * permitted to overlap inexactly as far as we are concerned for in
890 * these cases, sharing is handled in the driver or filesystem rather
891 * than here
892 */
893 if (vm_flags & VM_MAYSHARE) {
894 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
895 unsigned long vmpglen;
896
David Howells165b2392007-03-22 00:11:24 -0800897 /* suppress VMA sharing for shared regions */
898 if (vm_flags & VM_SHARED &&
899 capabilities & BDI_CAP_MAP_DIRECT)
900 goto dont_share_VMAs;
901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
903 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
904
905 if (!(vma->vm_flags & VM_MAYSHARE))
906 continue;
907
908 /* search for overlapping mappings on the same file */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800909 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 continue;
911
912 if (vma->vm_pgoff >= pgoff + pglen)
913 continue;
914
915 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
916 vmpglen >>= PAGE_SHIFT;
917 if (pgoff >= vma->vm_pgoff + vmpglen)
918 continue;
919
920 /* handle inexactly overlapping matches between mappings */
921 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
922 if (!(capabilities & BDI_CAP_MAP_DIRECT))
923 goto sharing_violation;
924 continue;
925 }
926
927 /* we've found a VMA we can share */
928 atomic_inc(&vma->vm_usage);
929
930 vml->vma = vma;
931 result = (void *) vma->vm_start;
932 goto shared;
933 }
934
David Howells165b2392007-03-22 00:11:24 -0800935 dont_share_VMAs:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936 vma = NULL;
937
938 /* obtain the address at which to make a shared mapping
939 * - this is the hook for quasi-memory character devices to
940 * tell us the location of a shared mapping
941 */
942 if (file && file->f_op->get_unmapped_area) {
943 addr = file->f_op->get_unmapped_area(file, addr, len,
944 pgoff, flags);
945 if (IS_ERR((void *) addr)) {
946 ret = addr;
947 if (ret != (unsigned long) -ENOSYS)
948 goto error;
949
950 /* the driver refused to tell us where to site
951 * the mapping so we'll have to attempt to copy
952 * it */
953 ret = (unsigned long) -ENODEV;
954 if (!(capabilities & BDI_CAP_MAP_COPY))
955 goto error;
956
957 capabilities &= ~BDI_CAP_MAP_DIRECT;
958 }
959 }
960 }
961
962 /* we're going to need a VMA struct as well */
Burman Yan4668edc2006-12-06 20:38:51 -0800963 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 if (!vma)
965 goto error_getting_vma;
966
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 INIT_LIST_HEAD(&vma->anon_vma_node);
968 atomic_set(&vma->vm_usage, 1);
Matt Helsley925d1c42008-04-29 01:01:36 -0700969 if (file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 get_file(file);
Matt Helsley925d1c42008-04-29 01:01:36 -0700971 if (vm_flags & VM_EXECUTABLE) {
972 added_exe_file_vma(current->mm);
973 vma->vm_mm = current->mm;
974 }
975 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 vma->vm_file = file;
977 vma->vm_flags = vm_flags;
978 vma->vm_start = addr;
979 vma->vm_end = addr + len;
980 vma->vm_pgoff = pgoff;
981
982 vml->vma = vma;
983
984 /* set up the mapping */
985 if (file && vma->vm_flags & VM_SHARED)
986 ret = do_mmap_shared_file(vma, len);
987 else
988 ret = do_mmap_private(vma, len);
989 if (ret < 0)
990 goto error;
991
992 /* okay... we have a mapping; now we have to register it */
993 result = (void *) vma->vm_start;
994
995 if (vma->vm_flags & VM_MAPPED_COPY) {
996 realalloc += kobjsize(result);
997 askedalloc += len;
998 }
999
1000 realalloc += kobjsize(vma);
1001 askedalloc += sizeof(*vma);
1002
1003 current->mm->total_vm += len >> PAGE_SHIFT;
1004
1005 add_nommu_vma(vma);
1006
1007 shared:
1008 realalloc += kobjsize(vml);
1009 askedalloc += sizeof(*vml);
1010
David Howells30340972006-09-27 01:50:20 -07001011 add_vma_to_mm(current->mm, vml);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012
1013 up_write(&nommu_vma_sem);
1014
1015 if (prot & PROT_EXEC)
1016 flush_icache_range((unsigned long) result,
1017 (unsigned long) result + len);
1018
1019#ifdef DEBUG
1020 printk("do_mmap:\n");
1021 show_process_blocks();
1022#endif
1023
1024 return (unsigned long) result;
1025
1026 error:
1027 up_write(&nommu_vma_sem);
1028 kfree(vml);
1029 if (vma) {
Matt Helsley925d1c42008-04-29 01:01:36 -07001030 if (vma->vm_file) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -07001031 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001032 if (vma->vm_flags & VM_EXECUTABLE)
1033 removed_exe_file_vma(vma->vm_mm);
1034 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 kfree(vma);
1036 }
1037 return ret;
1038
1039 sharing_violation:
1040 up_write(&nommu_vma_sem);
1041 printk("Attempt to share mismatched mappings\n");
1042 kfree(vml);
1043 return -EINVAL;
1044
1045 error_getting_vma:
1046 up_write(&nommu_vma_sem);
1047 kfree(vml);
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001048 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 len, current->pid);
1050 show_free_areas();
1051 return -ENOMEM;
1052
1053 error_getting_vml:
1054 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1055 len, current->pid);
1056 show_free_areas();
1057 return -ENOMEM;
1058}
Paul Mundtb5073172007-07-21 04:37:25 -07001059EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060
1061/*
1062 * handle mapping disposal for uClinux
1063 */
Matt Helsley925d1c42008-04-29 01:01:36 -07001064static void put_vma(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065{
1066 if (vma) {
1067 down_write(&nommu_vma_sem);
1068
1069 if (atomic_dec_and_test(&vma->vm_usage)) {
1070 delete_nommu_vma(vma);
1071
1072 if (vma->vm_ops && vma->vm_ops->close)
1073 vma->vm_ops->close(vma);
1074
1075 /* IO memory and memory shared directly out of the pagecache from
1076 * ramfs/tmpfs mustn't be released here */
1077 if (vma->vm_flags & VM_MAPPED_COPY) {
1078 realalloc -= kobjsize((void *) vma->vm_start);
1079 askedalloc -= vma->vm_end - vma->vm_start;
1080 kfree((void *) vma->vm_start);
1081 }
1082
1083 realalloc -= kobjsize(vma);
1084 askedalloc -= sizeof(*vma);
1085
Matt Helsley925d1c42008-04-29 01:01:36 -07001086 if (vma->vm_file) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001088 if (vma->vm_flags & VM_EXECUTABLE)
1089 removed_exe_file_vma(mm);
1090 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 kfree(vma);
1092 }
1093
1094 up_write(&nommu_vma_sem);
1095 }
1096}
1097
David Howells30340972006-09-27 01:50:20 -07001098/*
1099 * release a mapping
1100 * - under NOMMU conditions the parameters must match exactly to the mapping to
1101 * be removed
1102 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1104{
1105 struct vm_list_struct *vml, **parent;
1106 unsigned long end = addr + len;
1107
1108#ifdef DEBUG
1109 printk("do_munmap:\n");
1110#endif
1111
David Howells30340972006-09-27 01:50:20 -07001112 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1113 if ((*parent)->vma->vm_start > addr)
1114 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 if ((*parent)->vma->vm_start == addr &&
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001116 ((len == 0) || ((*parent)->vma->vm_end == end)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 goto found;
David Howells30340972006-09-27 01:50:20 -07001118 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119
1120 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1121 current->pid, current->comm, (void *) addr);
1122 return -EINVAL;
1123
1124 found:
1125 vml = *parent;
1126
Matt Helsley925d1c42008-04-29 01:01:36 -07001127 put_vma(mm, vml->vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128
1129 *parent = vml->next;
1130 realalloc -= kobjsize(vml);
1131 askedalloc -= sizeof(*vml);
1132 kfree(vml);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001133
1134 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 mm->total_vm -= len >> PAGE_SHIFT;
1136
1137#ifdef DEBUG
1138 show_process_blocks();
1139#endif
1140
1141 return 0;
1142}
Paul Mundtb5073172007-07-21 04:37:25 -07001143EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144
David Howells30340972006-09-27 01:50:20 -07001145asmlinkage long sys_munmap(unsigned long addr, size_t len)
1146{
1147 int ret;
1148 struct mm_struct *mm = current->mm;
1149
1150 down_write(&mm->mmap_sem);
1151 ret = do_munmap(mm, addr, len);
1152 up_write(&mm->mmap_sem);
1153 return ret;
1154}
1155
1156/*
1157 * Release all mappings
1158 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159void exit_mmap(struct mm_struct * mm)
1160{
1161 struct vm_list_struct *tmp;
1162
1163 if (mm) {
1164#ifdef DEBUG
1165 printk("Exit_mmap:\n");
1166#endif
1167
1168 mm->total_vm = 0;
1169
1170 while ((tmp = mm->context.vmlist)) {
1171 mm->context.vmlist = tmp->next;
Matt Helsley925d1c42008-04-29 01:01:36 -07001172 put_vma(mm, tmp->vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173
1174 realalloc -= kobjsize(tmp);
1175 askedalloc -= sizeof(*tmp);
1176 kfree(tmp);
1177 }
1178
1179#ifdef DEBUG
1180 show_process_blocks();
1181#endif
1182 }
1183}
1184
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185unsigned long do_brk(unsigned long addr, unsigned long len)
1186{
1187 return -ENOMEM;
1188}
1189
1190/*
David Howells6fa5f802006-09-27 01:50:21 -07001191 * expand (or shrink) an existing mapping, potentially moving it at the same
1192 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 *
David Howells6fa5f802006-09-27 01:50:21 -07001194 * under NOMMU conditions, we only permit changing a mapping's size, and only
1195 * as long as it stays within the hole allocated by the kmalloc() call in
1196 * do_mmap_pgoff() and the block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 *
David Howells6fa5f802006-09-27 01:50:21 -07001198 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 */
1200unsigned long do_mremap(unsigned long addr,
1201 unsigned long old_len, unsigned long new_len,
1202 unsigned long flags, unsigned long new_addr)
1203{
David Howells6fa5f802006-09-27 01:50:21 -07001204 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205
1206 /* insanity checks first */
1207 if (new_len == 0)
1208 return (unsigned long) -EINVAL;
1209
1210 if (flags & MREMAP_FIXED && new_addr != addr)
1211 return (unsigned long) -EINVAL;
1212
David Howells6fa5f802006-09-27 01:50:21 -07001213 vma = find_vma_exact(current->mm, addr);
1214 if (!vma)
1215 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216
David Howells6fa5f802006-09-27 01:50:21 -07001217 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 return (unsigned long) -EFAULT;
1219
David Howells6fa5f802006-09-27 01:50:21 -07001220 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 return (unsigned long) -EPERM;
1222
1223 if (new_len > kobjsize((void *) addr))
1224 return (unsigned long) -ENOMEM;
1225
1226 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001227 vma->vm_end = vma->vm_start + new_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228
1229 askedalloc -= old_len;
1230 askedalloc += new_len;
1231
David Howells6fa5f802006-09-27 01:50:21 -07001232 return vma->vm_start;
1233}
Paul Mundtb5073172007-07-21 04:37:25 -07001234EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001235
1236asmlinkage unsigned long sys_mremap(unsigned long addr,
1237 unsigned long old_len, unsigned long new_len,
1238 unsigned long flags, unsigned long new_addr)
1239{
1240 unsigned long ret;
1241
1242 down_write(&current->mm->mmap_sem);
1243 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1244 up_write(&current->mm->mmap_sem);
1245 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246}
1247
Linus Torvalds6aab3412005-11-28 14:34:23 -08001248struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001249 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250{
1251 return NULL;
1252}
1253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1255 unsigned long to, unsigned long size, pgprot_t prot)
1256{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001257 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1258 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259}
Luke Yang22c4af42006-07-14 00:24:09 -07001260EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
Paul Mundtf905bc42008-02-04 22:29:59 -08001262int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1263 unsigned long pgoff)
1264{
1265 unsigned int size = vma->vm_end - vma->vm_start;
1266
1267 if (!(vma->vm_flags & VM_USERMAP))
1268 return -EINVAL;
1269
1270 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1271 vma->vm_end = vma->vm_start + size;
1272
1273 return 0;
1274}
1275EXPORT_SYMBOL(remap_vmalloc_range);
1276
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1278{
1279}
1280
1281unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1282 unsigned long len, unsigned long pgoff, unsigned long flags)
1283{
1284 return -ENOMEM;
1285}
1286
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001287void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288{
1289}
1290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291void unmap_mapping_range(struct address_space *mapping,
1292 loff_t const holebegin, loff_t const holelen,
1293 int even_cows)
1294{
1295}
Luke Yang22c4af42006-07-14 00:24:09 -07001296EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297
1298/*
David Howellsd56e03c2007-03-22 00:11:23 -08001299 * ask for an unmapped area at which to create a mapping on a file
1300 */
1301unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1302 unsigned long len, unsigned long pgoff,
1303 unsigned long flags)
1304{
1305 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1306 unsigned long, unsigned long);
1307
1308 get_area = current->mm->get_unmapped_area;
1309 if (file && file->f_op && file->f_op->get_unmapped_area)
1310 get_area = file->f_op->get_unmapped_area;
1311
1312 if (!get_area)
1313 return -ENOSYS;
1314
1315 return get_area(file, addr, len, pgoff, flags);
1316}
David Howellsd56e03c2007-03-22 00:11:23 -08001317EXPORT_SYMBOL(get_unmapped_area);
1318
1319/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320 * Check that a process has enough memory to allocate a new virtual
1321 * mapping. 0 means there is enough memory for the allocation to
1322 * succeed and -ENOMEM implies there is not.
1323 *
1324 * We currently support three overcommit policies, which are set via the
1325 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1326 *
1327 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1328 * Additional code 2002 Jul 20 by Robert Love.
1329 *
1330 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1331 *
1332 * Note this is a helper function intended to be used by LSMs which
1333 * wish to use this logic.
1334 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001335int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336{
1337 unsigned long free, allowed;
1338
1339 vm_acct_memory(pages);
1340
1341 /*
1342 * Sometimes we want to use more memory than we have
1343 */
1344 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1345 return 0;
1346
1347 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1348 unsigned long n;
1349
Christoph Lameter347ce432006-06-30 01:55:35 -07001350 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 free += nr_swap_pages;
1352
1353 /*
1354 * Any slabs which are created with the
1355 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1356 * which are reclaimable, under pressure. The dentry
1357 * cache and most inode caches should fall into this
1358 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001359 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360
1361 /*
1362 * Leave the last 3% for root
1363 */
1364 if (!cap_sys_admin)
1365 free -= free / 32;
1366
1367 if (free > pages)
1368 return 0;
1369
1370 /*
1371 * nr_free_pages() is very expensive on large systems,
1372 * only call if we're about to fail.
1373 */
1374 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001375
1376 /*
1377 * Leave reserved pages. The pages are not for anonymous pages.
1378 */
1379 if (n <= totalreserve_pages)
1380 goto error;
1381 else
1382 n -= totalreserve_pages;
1383
1384 /*
1385 * Leave the last 3% for root
1386 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 if (!cap_sys_admin)
1388 n -= n / 32;
1389 free += n;
1390
1391 if (free > pages)
1392 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001393
1394 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 }
1396
1397 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1398 /*
1399 * Leave the last 3% for root
1400 */
1401 if (!cap_sys_admin)
1402 allowed -= allowed / 32;
1403 allowed += total_swap_pages;
1404
1405 /* Don't let a single process grow too big:
1406 leave 3% of the size of this process for other processes */
1407 allowed -= current->mm->total_vm / 32;
1408
Simon Derr2f60f8d2005-08-04 19:52:03 -07001409 /*
1410 * cast `allowed' as a signed long because vm_committed_space
1411 * sometimes has a negative value
1412 */
1413 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001415error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 vm_unacct_memory(pages);
1417
1418 return -ENOMEM;
1419}
1420
1421int in_gate_area_no_task(unsigned long addr)
1422{
1423 return 0;
1424}
David Howellsb0e15192006-01-06 00:11:42 -08001425
Nick Piggind0217ac2007-07-19 01:47:03 -07001426int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001427{
1428 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001429 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001430}
Paul Mundtb5073172007-07-21 04:37:25 -07001431EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001432
1433/*
1434 * Access another process' address space.
1435 * - source/target buffer must be kernel space
1436 */
1437int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1438{
David Howells0ec76a12006-09-27 01:50:15 -07001439 struct vm_area_struct *vma;
1440 struct mm_struct *mm;
1441
1442 if (addr + len < addr)
1443 return 0;
1444
1445 mm = get_task_mm(tsk);
1446 if (!mm)
1447 return 0;
1448
1449 down_read(&mm->mmap_sem);
1450
1451 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001452 vma = find_vma(mm, addr);
1453 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001454 /* don't overrun this mapping */
1455 if (addr + len >= vma->vm_end)
1456 len = vma->vm_end - addr;
1457
1458 /* only read or write mappings where it is permitted */
David Howellsd00c7b92006-09-27 01:50:19 -07001459 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001460 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b92006-09-27 01:50:19 -07001461 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001462 len -= copy_from_user(buf, (void *) addr, len);
1463 else
1464 len = 0;
1465 } else {
1466 len = 0;
1467 }
1468
1469 up_read(&mm->mmap_sem);
1470 mmput(mm);
1471 return len;
1472}