6 * Address space accounting code <alan@redhat.com>
9 #include <linux/slab.h>
11 #include <linux/shm.h>
12 #include <linux/mman.h>
13 #include <linux/pagemap.h>
14 #include <linux/swap.h>
15 #include <linux/syscalls.h>
16 #include <linux/capability.h>
17 #include <linux/init.h>
18 #include <linux/file.h>
20 #include <linux/personality.h>
21 #include <linux/security.h>
22 #include <linux/hugetlb.h>
23 #include <linux/profile.h>
24 #include <linux/module.h>
25 #include <linux/mount.h>
26 #include <linux/mempolicy.h>
27 #include <linux/rmap.h>
29 #include <asm/uaccess.h>
30 #include <asm/cacheflush.h>
33 static void unmap_region(struct mm_struct
*mm
,
34 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
35 unsigned long start
, unsigned long end
);
38 * WARNING: the debugging will use recursive algorithms so never enable this
39 * unless you know what you are doing.
43 /* description of effects of mapping type and prot in current implementation.
44 * this is due to the limited x86 page protection hardware. The expected
45 * behavior is in parens:
48 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
49 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
50 * w: (no) no w: (no) no w: (yes) yes w: (no) no
51 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
53 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
54 * w: (no) no w: (no) no w: (copy) copy w: (no) no
55 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
58 pgprot_t protection_map
[16] = {
59 __P000
, __P001
, __P010
, __P011
, __P100
, __P101
, __P110
, __P111
,
60 __S000
, __S001
, __S010
, __S011
, __S100
, __S101
, __S110
, __S111
63 pgprot_t
vm_get_page_prot(unsigned long vm_flags
)
65 return protection_map
[vm_flags
&
66 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)];
68 EXPORT_SYMBOL(vm_get_page_prot
);
70 int sysctl_overcommit_memory
= OVERCOMMIT_GUESS
; /* heuristic overcommit */
71 int sysctl_overcommit_ratio
= 50; /* default is 50% */
72 int sysctl_max_map_count __read_mostly
= DEFAULT_MAX_MAP_COUNT
;
73 atomic_t vm_committed_space
= ATOMIC_INIT(0);
76 * Check that a process has enough memory to allocate a new virtual
77 * mapping. 0 means there is enough memory for the allocation to
78 * succeed and -ENOMEM implies there is not.
80 * We currently support three overcommit policies, which are set via the
81 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
83 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
84 * Additional code 2002 Jul 20 by Robert Love.
86 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
88 * Note this is a helper function intended to be used by LSMs which
89 * wish to use this logic.
91 int __vm_enough_memory(long pages
, int cap_sys_admin
)
93 unsigned long free
, allowed
;
95 vm_acct_memory(pages
);
98 * Sometimes we want to use more memory than we have
100 if (sysctl_overcommit_memory
== OVERCOMMIT_ALWAYS
)
103 if (sysctl_overcommit_memory
== OVERCOMMIT_GUESS
) {
106 free
= global_page_state(NR_FILE_PAGES
);
107 free
+= nr_swap_pages
;
110 * Any slabs which are created with the
111 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
112 * which are reclaimable, under pressure. The dentry
113 * cache and most inode caches should fall into this
115 free
+= atomic_read(&slab_reclaim_pages
);
118 * Leave the last 3% for root
127 * nr_free_pages() is very expensive on large systems,
128 * only call if we're about to fail.
133 * Leave reserved pages. The pages are not for anonymous pages.
135 if (n
<= totalreserve_pages
)
138 n
-= totalreserve_pages
;
141 * Leave the last 3% for root
153 allowed
= (totalram_pages
- hugetlb_total_pages())
154 * sysctl_overcommit_ratio
/ 100;
156 * Leave the last 3% for root
159 allowed
-= allowed
/ 32;
160 allowed
+= total_swap_pages
;
162 /* Don't let a single process grow too big:
163 leave 3% of the size of this process for other processes */
164 allowed
-= current
->mm
->total_vm
/ 32;
167 * cast `allowed' as a signed long because vm_committed_space
168 * sometimes has a negative value
170 if (atomic_read(&vm_committed_space
) < (long)allowed
)
173 vm_unacct_memory(pages
);
178 EXPORT_SYMBOL(__vm_enough_memory
);
181 * Requires inode->i_mapping->i_mmap_lock
183 static void __remove_shared_vm_struct(struct vm_area_struct
*vma
,
184 struct file
*file
, struct address_space
*mapping
)
186 if (vma
->vm_flags
& VM_DENYWRITE
)
187 atomic_inc(&file
->f_dentry
->d_inode
->i_writecount
);
188 if (vma
->vm_flags
& VM_SHARED
)
189 mapping
->i_mmap_writable
--;
191 flush_dcache_mmap_lock(mapping
);
192 if (unlikely(vma
->vm_flags
& VM_NONLINEAR
))
193 list_del_init(&vma
->shared
.vm_set
.list
);
195 vma_prio_tree_remove(vma
, &mapping
->i_mmap
);
196 flush_dcache_mmap_unlock(mapping
);
200 * Unlink a file-based vm structure from its prio_tree, to hide
201 * vma from rmap and vmtruncate before freeing its page tables.
203 void unlink_file_vma(struct vm_area_struct
*vma
)
205 struct file
*file
= vma
->vm_file
;
208 struct address_space
*mapping
= file
->f_mapping
;
209 spin_lock(&mapping
->i_mmap_lock
);
210 __remove_shared_vm_struct(vma
, file
, mapping
);
211 spin_unlock(&mapping
->i_mmap_lock
);
216 * Close a vm structure and free it, returning the next.
218 static struct vm_area_struct
*remove_vma(struct vm_area_struct
*vma
)
220 struct vm_area_struct
*next
= vma
->vm_next
;
223 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
224 vma
->vm_ops
->close(vma
);
227 mpol_free(vma_policy(vma
));
228 kmem_cache_free(vm_area_cachep
, vma
);
232 asmlinkage
unsigned long sys_brk(unsigned long brk
)
234 unsigned long rlim
, retval
;
235 unsigned long newbrk
, oldbrk
;
236 struct mm_struct
*mm
= current
->mm
;
238 down_write(&mm
->mmap_sem
);
240 if (brk
< mm
->end_code
)
244 * Check against rlimit here. If this check is done later after the test
245 * of oldbrk with newbrk then it can escape the test and let the data
246 * segment grow beyond its set limit the in case where the limit is
247 * not page aligned -Ram Gupta
249 rlim
= current
->signal
->rlim
[RLIMIT_DATA
].rlim_cur
;
250 if (rlim
< RLIM_INFINITY
&& brk
- mm
->start_data
> rlim
)
253 newbrk
= PAGE_ALIGN(brk
);
254 oldbrk
= PAGE_ALIGN(mm
->brk
);
255 if (oldbrk
== newbrk
)
258 /* Always allow shrinking brk. */
259 if (brk
<= mm
->brk
) {
260 if (!do_munmap(mm
, newbrk
, oldbrk
-newbrk
))
265 /* Check against existing mmap mappings. */
266 if (find_vma_intersection(mm
, oldbrk
, newbrk
+PAGE_SIZE
))
269 /* Ok, looks good - let it rip. */
270 if (do_brk(oldbrk
, newbrk
-oldbrk
) != oldbrk
)
276 up_write(&mm
->mmap_sem
);
281 static int browse_rb(struct rb_root
*root
)
284 struct rb_node
*nd
, *pn
= NULL
;
285 unsigned long prev
= 0, pend
= 0;
287 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
288 struct vm_area_struct
*vma
;
289 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
290 if (vma
->vm_start
< prev
)
291 printk("vm_start %lx prev %lx\n", vma
->vm_start
, prev
), i
= -1;
292 if (vma
->vm_start
< pend
)
293 printk("vm_start %lx pend %lx\n", vma
->vm_start
, pend
);
294 if (vma
->vm_start
> vma
->vm_end
)
295 printk("vm_end %lx < vm_start %lx\n", vma
->vm_end
, vma
->vm_start
);
300 for (nd
= pn
; nd
; nd
= rb_prev(nd
)) {
304 printk("backwards %d, forwards %d\n", j
, i
), i
= 0;
308 void validate_mm(struct mm_struct
*mm
)
312 struct vm_area_struct
*tmp
= mm
->mmap
;
317 if (i
!= mm
->map_count
)
318 printk("map_count %d vm_next %d\n", mm
->map_count
, i
), bug
= 1;
319 i
= browse_rb(&mm
->mm_rb
);
320 if (i
!= mm
->map_count
)
321 printk("map_count %d rb %d\n", mm
->map_count
, i
), bug
= 1;
325 #define validate_mm(mm) do { } while (0)
328 static struct vm_area_struct
*
329 find_vma_prepare(struct mm_struct
*mm
, unsigned long addr
,
330 struct vm_area_struct
**pprev
, struct rb_node
***rb_link
,
331 struct rb_node
** rb_parent
)
333 struct vm_area_struct
* vma
;
334 struct rb_node
** __rb_link
, * __rb_parent
, * rb_prev
;
336 __rb_link
= &mm
->mm_rb
.rb_node
;
337 rb_prev
= __rb_parent
= NULL
;
341 struct vm_area_struct
*vma_tmp
;
343 __rb_parent
= *__rb_link
;
344 vma_tmp
= rb_entry(__rb_parent
, struct vm_area_struct
, vm_rb
);
346 if (vma_tmp
->vm_end
> addr
) {
348 if (vma_tmp
->vm_start
<= addr
)
350 __rb_link
= &__rb_parent
->rb_left
;
352 rb_prev
= __rb_parent
;
353 __rb_link
= &__rb_parent
->rb_right
;
359 *pprev
= rb_entry(rb_prev
, struct vm_area_struct
, vm_rb
);
360 *rb_link
= __rb_link
;
361 *rb_parent
= __rb_parent
;
366 __vma_link_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
367 struct vm_area_struct
*prev
, struct rb_node
*rb_parent
)
370 vma
->vm_next
= prev
->vm_next
;
375 vma
->vm_next
= rb_entry(rb_parent
,
376 struct vm_area_struct
, vm_rb
);
382 void __vma_link_rb(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
383 struct rb_node
**rb_link
, struct rb_node
*rb_parent
)
385 rb_link_node(&vma
->vm_rb
, rb_parent
, rb_link
);
386 rb_insert_color(&vma
->vm_rb
, &mm
->mm_rb
);
389 static inline void __vma_link_file(struct vm_area_struct
*vma
)
395 struct address_space
*mapping
= file
->f_mapping
;
397 if (vma
->vm_flags
& VM_DENYWRITE
)
398 atomic_dec(&file
->f_dentry
->d_inode
->i_writecount
);
399 if (vma
->vm_flags
& VM_SHARED
)
400 mapping
->i_mmap_writable
++;
402 flush_dcache_mmap_lock(mapping
);
403 if (unlikely(vma
->vm_flags
& VM_NONLINEAR
))
404 vma_nonlinear_insert(vma
, &mapping
->i_mmap_nonlinear
);
406 vma_prio_tree_insert(vma
, &mapping
->i_mmap
);
407 flush_dcache_mmap_unlock(mapping
);
412 __vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
413 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
414 struct rb_node
*rb_parent
)
416 __vma_link_list(mm
, vma
, prev
, rb_parent
);
417 __vma_link_rb(mm
, vma
, rb_link
, rb_parent
);
418 __anon_vma_link(vma
);
421 static void vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
422 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
423 struct rb_node
*rb_parent
)
425 struct address_space
*mapping
= NULL
;
428 mapping
= vma
->vm_file
->f_mapping
;
431 spin_lock(&mapping
->i_mmap_lock
);
432 vma
->vm_truncate_count
= mapping
->truncate_count
;
436 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
437 __vma_link_file(vma
);
439 anon_vma_unlock(vma
);
441 spin_unlock(&mapping
->i_mmap_lock
);
448 * Helper for vma_adjust in the split_vma insert case:
449 * insert vm structure into list and rbtree and anon_vma,
450 * but it has already been inserted into prio_tree earlier.
453 __insert_vm_struct(struct mm_struct
* mm
, struct vm_area_struct
* vma
)
455 struct vm_area_struct
* __vma
, * prev
;
456 struct rb_node
** rb_link
, * rb_parent
;
458 __vma
= find_vma_prepare(mm
, vma
->vm_start
,&prev
, &rb_link
, &rb_parent
);
459 BUG_ON(__vma
&& __vma
->vm_start
< vma
->vm_end
);
460 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
465 __vma_unlink(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
466 struct vm_area_struct
*prev
)
468 prev
->vm_next
= vma
->vm_next
;
469 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
470 if (mm
->mmap_cache
== vma
)
471 mm
->mmap_cache
= prev
;
475 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
476 * is already present in an i_mmap tree without adjusting the tree.
477 * The following helper function should be used when such adjustments
478 * are necessary. The "insert" vma (if any) is to be inserted
479 * before we drop the necessary locks.
481 void vma_adjust(struct vm_area_struct
*vma
, unsigned long start
,
482 unsigned long end
, pgoff_t pgoff
, struct vm_area_struct
*insert
)
484 struct mm_struct
*mm
= vma
->vm_mm
;
485 struct vm_area_struct
*next
= vma
->vm_next
;
486 struct vm_area_struct
*importer
= NULL
;
487 struct address_space
*mapping
= NULL
;
488 struct prio_tree_root
*root
= NULL
;
489 struct file
*file
= vma
->vm_file
;
490 struct anon_vma
*anon_vma
= NULL
;
491 long adjust_next
= 0;
494 if (next
&& !insert
) {
495 if (end
>= next
->vm_end
) {
497 * vma expands, overlapping all the next, and
498 * perhaps the one after too (mprotect case 6).
500 again
: remove_next
= 1 + (end
> next
->vm_end
);
502 anon_vma
= next
->anon_vma
;
504 } else if (end
> next
->vm_start
) {
506 * vma expands, overlapping part of the next:
507 * mprotect case 5 shifting the boundary up.
509 adjust_next
= (end
- next
->vm_start
) >> PAGE_SHIFT
;
510 anon_vma
= next
->anon_vma
;
512 } else if (end
< vma
->vm_end
) {
514 * vma shrinks, and !insert tells it's not
515 * split_vma inserting another: so it must be
516 * mprotect case 4 shifting the boundary down.
518 adjust_next
= - ((vma
->vm_end
- end
) >> PAGE_SHIFT
);
519 anon_vma
= next
->anon_vma
;
525 mapping
= file
->f_mapping
;
526 if (!(vma
->vm_flags
& VM_NONLINEAR
))
527 root
= &mapping
->i_mmap
;
528 spin_lock(&mapping
->i_mmap_lock
);
530 vma
->vm_truncate_count
!= next
->vm_truncate_count
) {
532 * unmap_mapping_range might be in progress:
533 * ensure that the expanding vma is rescanned.
535 importer
->vm_truncate_count
= 0;
538 insert
->vm_truncate_count
= vma
->vm_truncate_count
;
540 * Put into prio_tree now, so instantiated pages
541 * are visible to arm/parisc __flush_dcache_page
542 * throughout; but we cannot insert into address
543 * space until vma start or end is updated.
545 __vma_link_file(insert
);
550 * When changing only vma->vm_end, we don't really need
551 * anon_vma lock: but is that case worth optimizing out?
554 anon_vma
= vma
->anon_vma
;
556 spin_lock(&anon_vma
->lock
);
558 * Easily overlooked: when mprotect shifts the boundary,
559 * make sure the expanding vma has anon_vma set if the
560 * shrinking vma had, to cover any anon pages imported.
562 if (importer
&& !importer
->anon_vma
) {
563 importer
->anon_vma
= anon_vma
;
564 __anon_vma_link(importer
);
569 flush_dcache_mmap_lock(mapping
);
570 vma_prio_tree_remove(vma
, root
);
572 vma_prio_tree_remove(next
, root
);
575 vma
->vm_start
= start
;
577 vma
->vm_pgoff
= pgoff
;
579 next
->vm_start
+= adjust_next
<< PAGE_SHIFT
;
580 next
->vm_pgoff
+= adjust_next
;
585 vma_prio_tree_insert(next
, root
);
586 vma_prio_tree_insert(vma
, root
);
587 flush_dcache_mmap_unlock(mapping
);
592 * vma_merge has merged next into vma, and needs
593 * us to remove next before dropping the locks.
595 __vma_unlink(mm
, next
, vma
);
597 __remove_shared_vm_struct(next
, file
, mapping
);
599 __anon_vma_merge(vma
, next
);
602 * split_vma has split insert from vma, and needs
603 * us to insert it before dropping the locks
604 * (it may either follow vma or precede it).
606 __insert_vm_struct(mm
, insert
);
610 spin_unlock(&anon_vma
->lock
);
612 spin_unlock(&mapping
->i_mmap_lock
);
618 mpol_free(vma_policy(next
));
619 kmem_cache_free(vm_area_cachep
, next
);
621 * In mprotect's case 6 (see comments on vma_merge),
622 * we must remove another next too. It would clutter
623 * up the code too much to do both in one go.
625 if (remove_next
== 2) {
635 * If the vma has a ->close operation then the driver probably needs to release
636 * per-vma resources, so we don't attempt to merge those.
638 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
640 static inline int is_mergeable_vma(struct vm_area_struct
*vma
,
641 struct file
*file
, unsigned long vm_flags
)
643 if (vma
->vm_flags
!= vm_flags
)
645 if (vma
->vm_file
!= file
)
647 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
652 static inline int is_mergeable_anon_vma(struct anon_vma
*anon_vma1
,
653 struct anon_vma
*anon_vma2
)
655 return !anon_vma1
|| !anon_vma2
|| (anon_vma1
== anon_vma2
);
659 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
660 * in front of (at a lower virtual address and file offset than) the vma.
662 * We cannot merge two vmas if they have differently assigned (non-NULL)
663 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
665 * We don't check here for the merged mmap wrapping around the end of pagecache
666 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
667 * wrap, nor mmaps which cover the final page at index -1UL.
670 can_vma_merge_before(struct vm_area_struct
*vma
, unsigned long vm_flags
,
671 struct anon_vma
*anon_vma
, struct file
*file
, pgoff_t vm_pgoff
)
673 if (is_mergeable_vma(vma
, file
, vm_flags
) &&
674 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
)) {
675 if (vma
->vm_pgoff
== vm_pgoff
)
682 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
683 * beyond (at a higher virtual address and file offset than) the vma.
685 * We cannot merge two vmas if they have differently assigned (non-NULL)
686 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
689 can_vma_merge_after(struct vm_area_struct
*vma
, unsigned long vm_flags
,
690 struct anon_vma
*anon_vma
, struct file
*file
, pgoff_t vm_pgoff
)
692 if (is_mergeable_vma(vma
, file
, vm_flags
) &&
693 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
)) {
695 vm_pglen
= (vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
;
696 if (vma
->vm_pgoff
+ vm_pglen
== vm_pgoff
)
703 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
704 * whether that can be merged with its predecessor or its successor.
705 * Or both (it neatly fills a hole).
707 * In most cases - when called for mmap, brk or mremap - [addr,end) is
708 * certain not to be mapped by the time vma_merge is called; but when
709 * called for mprotect, it is certain to be already mapped (either at
710 * an offset within prev, or at the start of next), and the flags of
711 * this area are about to be changed to vm_flags - and the no-change
712 * case has already been eliminated.
714 * The following mprotect cases have to be considered, where AAAA is
715 * the area passed down from mprotect_fixup, never extending beyond one
716 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
718 * AAAA AAAA AAAA AAAA
719 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
720 * cannot merge might become might become might become
721 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
722 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
723 * mremap move: PPPPNNNNNNNN 8
725 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
726 * might become case 1 below case 2 below case 3 below
728 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
729 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
731 struct vm_area_struct
*vma_merge(struct mm_struct
*mm
,
732 struct vm_area_struct
*prev
, unsigned long addr
,
733 unsigned long end
, unsigned long vm_flags
,
734 struct anon_vma
*anon_vma
, struct file
*file
,
735 pgoff_t pgoff
, struct mempolicy
*policy
)
737 pgoff_t pglen
= (end
- addr
) >> PAGE_SHIFT
;
738 struct vm_area_struct
*area
, *next
;
741 * We later require that vma->vm_flags == vm_flags,
742 * so this tests vma->vm_flags & VM_SPECIAL, too.
744 if (vm_flags
& VM_SPECIAL
)
748 next
= prev
->vm_next
;
752 if (next
&& next
->vm_end
== end
) /* cases 6, 7, 8 */
753 next
= next
->vm_next
;
756 * Can it merge with the predecessor?
758 if (prev
&& prev
->vm_end
== addr
&&
759 mpol_equal(vma_policy(prev
), policy
) &&
760 can_vma_merge_after(prev
, vm_flags
,
761 anon_vma
, file
, pgoff
)) {
763 * OK, it can. Can we now merge in the successor as well?
765 if (next
&& end
== next
->vm_start
&&
766 mpol_equal(policy
, vma_policy(next
)) &&
767 can_vma_merge_before(next
, vm_flags
,
768 anon_vma
, file
, pgoff
+pglen
) &&
769 is_mergeable_anon_vma(prev
->anon_vma
,
772 vma_adjust(prev
, prev
->vm_start
,
773 next
->vm_end
, prev
->vm_pgoff
, NULL
);
774 } else /* cases 2, 5, 7 */
775 vma_adjust(prev
, prev
->vm_start
,
776 end
, prev
->vm_pgoff
, NULL
);
781 * Can this new request be merged in front of next?
783 if (next
&& end
== next
->vm_start
&&
784 mpol_equal(policy
, vma_policy(next
)) &&
785 can_vma_merge_before(next
, vm_flags
,
786 anon_vma
, file
, pgoff
+pglen
)) {
787 if (prev
&& addr
< prev
->vm_end
) /* case 4 */
788 vma_adjust(prev
, prev
->vm_start
,
789 addr
, prev
->vm_pgoff
, NULL
);
790 else /* cases 3, 8 */
791 vma_adjust(area
, addr
, next
->vm_end
,
792 next
->vm_pgoff
- pglen
, NULL
);
800 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
801 * neighbouring vmas for a suitable anon_vma, before it goes off
802 * to allocate a new anon_vma. It checks because a repetitive
803 * sequence of mprotects and faults may otherwise lead to distinct
804 * anon_vmas being allocated, preventing vma merge in subsequent
807 struct anon_vma
*find_mergeable_anon_vma(struct vm_area_struct
*vma
)
809 struct vm_area_struct
*near
;
810 unsigned long vm_flags
;
817 * Since only mprotect tries to remerge vmas, match flags
818 * which might be mprotected into each other later on.
819 * Neither mlock nor madvise tries to remerge at present,
820 * so leave their flags as obstructing a merge.
822 vm_flags
= vma
->vm_flags
& ~(VM_READ
|VM_WRITE
|VM_EXEC
);
823 vm_flags
|= near
->vm_flags
& (VM_READ
|VM_WRITE
|VM_EXEC
);
825 if (near
->anon_vma
&& vma
->vm_end
== near
->vm_start
&&
826 mpol_equal(vma_policy(vma
), vma_policy(near
)) &&
827 can_vma_merge_before(near
, vm_flags
,
828 NULL
, vma
->vm_file
, vma
->vm_pgoff
+
829 ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
)))
830 return near
->anon_vma
;
833 * It is potentially slow to have to call find_vma_prev here.
834 * But it's only on the first write fault on the vma, not
835 * every time, and we could devise a way to avoid it later
836 * (e.g. stash info in next's anon_vma_node when assigning
837 * an anon_vma, or when trying vma_merge). Another time.
839 BUG_ON(find_vma_prev(vma
->vm_mm
, vma
->vm_start
, &near
) != vma
);
843 vm_flags
= vma
->vm_flags
& ~(VM_READ
|VM_WRITE
|VM_EXEC
);
844 vm_flags
|= near
->vm_flags
& (VM_READ
|VM_WRITE
|VM_EXEC
);
846 if (near
->anon_vma
&& near
->vm_end
== vma
->vm_start
&&
847 mpol_equal(vma_policy(near
), vma_policy(vma
)) &&
848 can_vma_merge_after(near
, vm_flags
,
849 NULL
, vma
->vm_file
, vma
->vm_pgoff
))
850 return near
->anon_vma
;
853 * There's no absolute need to look only at touching neighbours:
854 * we could search further afield for "compatible" anon_vmas.
855 * But it would probably just be a waste of time searching,
856 * or lead to too many vmas hanging off the same anon_vma.
857 * We're trying to allow mprotect remerging later on,
858 * not trying to minimize memory used for anon_vmas.
863 #ifdef CONFIG_PROC_FS
864 void vm_stat_account(struct mm_struct
*mm
, unsigned long flags
,
865 struct file
*file
, long pages
)
867 const unsigned long stack_flags
868 = VM_STACK_FLAGS
& (VM_GROWSUP
|VM_GROWSDOWN
);
871 mm
->shared_vm
+= pages
;
872 if ((flags
& (VM_EXEC
|VM_WRITE
)) == VM_EXEC
)
873 mm
->exec_vm
+= pages
;
874 } else if (flags
& stack_flags
)
875 mm
->stack_vm
+= pages
;
876 if (flags
& (VM_RESERVED
|VM_IO
))
877 mm
->reserved_vm
+= pages
;
879 #endif /* CONFIG_PROC_FS */
882 * The caller must hold down_write(current->mm->mmap_sem).
885 unsigned long do_mmap_pgoff(struct file
* file
, unsigned long addr
,
886 unsigned long len
, unsigned long prot
,
887 unsigned long flags
, unsigned long pgoff
)
889 struct mm_struct
* mm
= current
->mm
;
890 struct vm_area_struct
* vma
, * prev
;
892 unsigned int vm_flags
;
893 int correct_wcount
= 0;
895 struct rb_node
** rb_link
, * rb_parent
;
897 unsigned long charged
= 0, reqprot
= prot
;
900 if (is_file_hugepages(file
))
903 if (!file
->f_op
|| !file
->f_op
->mmap
)
906 if ((prot
& PROT_EXEC
) &&
907 (file
->f_vfsmnt
->mnt_flags
& MNT_NOEXEC
))
911 * Does the application expect PROT_READ to imply PROT_EXEC?
913 * (the exception is when the underlying filesystem is noexec
914 * mounted, in which case we dont add PROT_EXEC.)
916 if ((prot
& PROT_READ
) && (current
->personality
& READ_IMPLIES_EXEC
))
917 if (!(file
&& (file
->f_vfsmnt
->mnt_flags
& MNT_NOEXEC
)))
923 /* Careful about overflows.. */
924 len
= PAGE_ALIGN(len
);
925 if (!len
|| len
> TASK_SIZE
)
928 /* offset overflow? */
929 if ((pgoff
+ (len
>> PAGE_SHIFT
)) < pgoff
)
932 /* Too many mappings? */
933 if (mm
->map_count
> sysctl_max_map_count
)
936 /* Obtain the address to map to. we verify (or select) it and ensure
937 * that it represents a valid section of the address space.
939 addr
= get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
940 if (addr
& ~PAGE_MASK
)
943 /* Do simple checking here so the lower-level routines won't have
944 * to. we assume access permissions have been handled by the open
945 * of the memory object, so we don't do any here.
947 vm_flags
= calc_vm_prot_bits(prot
) | calc_vm_flag_bits(flags
) |
948 mm
->def_flags
| VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
950 if (flags
& MAP_LOCKED
) {
953 vm_flags
|= VM_LOCKED
;
955 /* mlock MCL_FUTURE? */
956 if (vm_flags
& VM_LOCKED
) {
957 unsigned long locked
, lock_limit
;
958 locked
= len
>> PAGE_SHIFT
;
959 locked
+= mm
->locked_vm
;
960 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
961 lock_limit
>>= PAGE_SHIFT
;
962 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
966 inode
= file
? file
->f_dentry
->d_inode
: NULL
;
969 switch (flags
& MAP_TYPE
) {
971 if ((prot
&PROT_WRITE
) && !(file
->f_mode
&FMODE_WRITE
))
975 * Make sure we don't allow writing to an append-only
978 if (IS_APPEND(inode
) && (file
->f_mode
& FMODE_WRITE
))
982 * Make sure there are no mandatory locks on the file.
984 if (locks_verify_locked(inode
))
987 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
988 if (!(file
->f_mode
& FMODE_WRITE
))
989 vm_flags
&= ~(VM_MAYWRITE
| VM_SHARED
);
993 if (!(file
->f_mode
& FMODE_READ
))
1001 switch (flags
& MAP_TYPE
) {
1003 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1007 * Set pgoff according to addr for anon_vma.
1009 pgoff
= addr
>> PAGE_SHIFT
;
1016 error
= security_file_mmap(file
, reqprot
, prot
, flags
);
1020 /* Clear old maps */
1023 vma
= find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
1024 if (vma
&& vma
->vm_start
< addr
+ len
) {
1025 if (do_munmap(mm
, addr
, len
))
1030 /* Check against address space limit. */
1031 if (!may_expand_vm(mm
, len
>> PAGE_SHIFT
))
1034 if (accountable
&& (!(flags
& MAP_NORESERVE
) ||
1035 sysctl_overcommit_memory
== OVERCOMMIT_NEVER
)) {
1036 if (vm_flags
& VM_SHARED
) {
1037 /* Check memory availability in shmem_file_setup? */
1038 vm_flags
|= VM_ACCOUNT
;
1039 } else if (vm_flags
& VM_WRITE
) {
1041 * Private writable mapping: check memory availability
1043 charged
= len
>> PAGE_SHIFT
;
1044 if (security_vm_enough_memory(charged
))
1046 vm_flags
|= VM_ACCOUNT
;
1051 * Can we just expand an old private anonymous mapping?
1052 * The VM_SHARED test is necessary because shmem_zero_setup
1053 * will create the file object for a shared anonymous map below.
1055 if (!file
&& !(vm_flags
& VM_SHARED
) &&
1056 vma_merge(mm
, prev
, addr
, addr
+ len
, vm_flags
,
1057 NULL
, NULL
, pgoff
, NULL
))
1061 * Determine the object being mapped and call the appropriate
1062 * specific mapper. the address has already been validated, but
1063 * not unmapped, but the maps are removed from the list.
1065 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1072 vma
->vm_start
= addr
;
1073 vma
->vm_end
= addr
+ len
;
1074 vma
->vm_flags
= vm_flags
;
1075 vma
->vm_page_prot
= protection_map
[vm_flags
&
1076 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)];
1077 vma
->vm_pgoff
= pgoff
;
1081 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1083 if (vm_flags
& VM_DENYWRITE
) {
1084 error
= deny_write_access(file
);
1089 vma
->vm_file
= file
;
1091 error
= file
->f_op
->mmap(file
, vma
);
1093 goto unmap_and_free_vma
;
1094 } else if (vm_flags
& VM_SHARED
) {
1095 error
= shmem_zero_setup(vma
);
1100 /* Don't make the VMA automatically writable if it's shared, but the
1101 * backer wishes to know when pages are first written to */
1102 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
)
1104 protection_map
[vm_flags
& (VM_READ
|VM_WRITE
|VM_EXEC
)];
1106 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1107 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1108 * that memory reservation must be checked; but that reservation
1109 * belongs to shared memory object, not to vma: so now clear it.
1111 if ((vm_flags
& (VM_SHARED
|VM_ACCOUNT
)) == (VM_SHARED
|VM_ACCOUNT
))
1112 vma
->vm_flags
&= ~VM_ACCOUNT
;
1114 /* Can addr have changed??
1116 * Answer: Yes, several device drivers can do it in their
1117 * f_op->mmap method. -DaveM
1119 addr
= vma
->vm_start
;
1120 pgoff
= vma
->vm_pgoff
;
1121 vm_flags
= vma
->vm_flags
;
1123 if (!file
|| !vma_merge(mm
, prev
, addr
, vma
->vm_end
,
1124 vma
->vm_flags
, NULL
, file
, pgoff
, vma_policy(vma
))) {
1125 file
= vma
->vm_file
;
1126 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
1128 atomic_inc(&inode
->i_writecount
);
1132 atomic_inc(&inode
->i_writecount
);
1135 mpol_free(vma_policy(vma
));
1136 kmem_cache_free(vm_area_cachep
, vma
);
1139 mm
->total_vm
+= len
>> PAGE_SHIFT
;
1140 vm_stat_account(mm
, vm_flags
, file
, len
>> PAGE_SHIFT
);
1141 if (vm_flags
& VM_LOCKED
) {
1142 mm
->locked_vm
+= len
>> PAGE_SHIFT
;
1143 make_pages_present(addr
, addr
+ len
);
1145 if (flags
& MAP_POPULATE
) {
1146 up_write(&mm
->mmap_sem
);
1147 sys_remap_file_pages(addr
, len
, 0,
1148 pgoff
, flags
& MAP_NONBLOCK
);
1149 down_write(&mm
->mmap_sem
);
1155 atomic_inc(&inode
->i_writecount
);
1156 vma
->vm_file
= NULL
;
1159 /* Undo any partial mapping done by a device driver. */
1160 unmap_region(mm
, vma
, prev
, vma
->vm_start
, vma
->vm_end
);
1163 kmem_cache_free(vm_area_cachep
, vma
);
1166 vm_unacct_memory(charged
);
1170 EXPORT_SYMBOL(do_mmap_pgoff
);
1172 /* Get an address range which is currently unmapped.
1173 * For shmat() with addr=0.
1175 * Ugly calling convention alert:
1176 * Return value with the low bits set means error value,
1178 * if (ret & ~PAGE_MASK)
1181 * This function "knows" that -ENOMEM has the bits set.
1183 #ifndef HAVE_ARCH_UNMAPPED_AREA
1185 arch_get_unmapped_area(struct file
*filp
, unsigned long addr
,
1186 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
1188 struct mm_struct
*mm
= current
->mm
;
1189 struct vm_area_struct
*vma
;
1190 unsigned long start_addr
;
1192 if (len
> TASK_SIZE
)
1196 addr
= PAGE_ALIGN(addr
);
1197 vma
= find_vma(mm
, addr
);
1198 if (TASK_SIZE
- len
>= addr
&&
1199 (!vma
|| addr
+ len
<= vma
->vm_start
))
1202 if (len
> mm
->cached_hole_size
) {
1203 start_addr
= addr
= mm
->free_area_cache
;
1205 start_addr
= addr
= TASK_UNMAPPED_BASE
;
1206 mm
->cached_hole_size
= 0;
1210 for (vma
= find_vma(mm
, addr
); ; vma
= vma
->vm_next
) {
1211 /* At this point: (!vma || addr < vma->vm_end). */
1212 if (TASK_SIZE
- len
< addr
) {
1214 * Start a new search - just in case we missed
1217 if (start_addr
!= TASK_UNMAPPED_BASE
) {
1218 addr
= TASK_UNMAPPED_BASE
;
1220 mm
->cached_hole_size
= 0;
1225 if (!vma
|| addr
+ len
<= vma
->vm_start
) {
1227 * Remember the place where we stopped the search:
1229 mm
->free_area_cache
= addr
+ len
;
1232 if (addr
+ mm
->cached_hole_size
< vma
->vm_start
)
1233 mm
->cached_hole_size
= vma
->vm_start
- addr
;
1239 void arch_unmap_area(struct mm_struct
*mm
, unsigned long addr
)
1242 * Is this a new hole at the lowest possible address?
1244 if (addr
>= TASK_UNMAPPED_BASE
&& addr
< mm
->free_area_cache
) {
1245 mm
->free_area_cache
= addr
;
1246 mm
->cached_hole_size
= ~0UL;
1251 * This mmap-allocator allocates new areas top-down from below the
1252 * stack's low limit (the base):
1254 #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1256 arch_get_unmapped_area_topdown(struct file
*filp
, const unsigned long addr0
,
1257 const unsigned long len
, const unsigned long pgoff
,
1258 const unsigned long flags
)
1260 struct vm_area_struct
*vma
;
1261 struct mm_struct
*mm
= current
->mm
;
1262 unsigned long addr
= addr0
;
1264 /* requested length too big for entire address space */
1265 if (len
> TASK_SIZE
)
1268 /* requesting a specific address */
1270 addr
= PAGE_ALIGN(addr
);
1271 vma
= find_vma(mm
, addr
);
1272 if (TASK_SIZE
- len
>= addr
&&
1273 (!vma
|| addr
+ len
<= vma
->vm_start
))
1277 /* check if free_area_cache is useful for us */
1278 if (len
<= mm
->cached_hole_size
) {
1279 mm
->cached_hole_size
= 0;
1280 mm
->free_area_cache
= mm
->mmap_base
;
1283 /* either no address requested or can't fit in requested address hole */
1284 addr
= mm
->free_area_cache
;
1286 /* make sure it can fit in the remaining address space */
1288 vma
= find_vma(mm
, addr
-len
);
1289 if (!vma
|| addr
<= vma
->vm_start
)
1290 /* remember the address as a hint for next time */
1291 return (mm
->free_area_cache
= addr
-len
);
1294 if (mm
->mmap_base
< len
)
1297 addr
= mm
->mmap_base
-len
;
1301 * Lookup failure means no vma is above this address,
1302 * else if new region fits below vma->vm_start,
1303 * return with success:
1305 vma
= find_vma(mm
, addr
);
1306 if (!vma
|| addr
+len
<= vma
->vm_start
)
1307 /* remember the address as a hint for next time */
1308 return (mm
->free_area_cache
= addr
);
1310 /* remember the largest hole we saw so far */
1311 if (addr
+ mm
->cached_hole_size
< vma
->vm_start
)
1312 mm
->cached_hole_size
= vma
->vm_start
- addr
;
1314 /* try just below the current vma->vm_start */
1315 addr
= vma
->vm_start
-len
;
1316 } while (len
< vma
->vm_start
);
1320 * A failed mmap() very likely causes application failure,
1321 * so fall back to the bottom-up function here. This scenario
1322 * can happen with large stack limits and large mmap()
1325 mm
->cached_hole_size
= ~0UL;
1326 mm
->free_area_cache
= TASK_UNMAPPED_BASE
;
1327 addr
= arch_get_unmapped_area(filp
, addr0
, len
, pgoff
, flags
);
1329 * Restore the topdown base:
1331 mm
->free_area_cache
= mm
->mmap_base
;
1332 mm
->cached_hole_size
= ~0UL;
1338 void arch_unmap_area_topdown(struct mm_struct
*mm
, unsigned long addr
)
1341 * Is this a new hole at the highest possible address?
1343 if (addr
> mm
->free_area_cache
)
1344 mm
->free_area_cache
= addr
;
1346 /* dont allow allocations above current base */
1347 if (mm
->free_area_cache
> mm
->mmap_base
)
1348 mm
->free_area_cache
= mm
->mmap_base
;
1352 get_unmapped_area(struct file
*file
, unsigned long addr
, unsigned long len
,
1353 unsigned long pgoff
, unsigned long flags
)
1357 if (!(flags
& MAP_FIXED
)) {
1358 unsigned long (*get_area
)(struct file
*, unsigned long, unsigned long, unsigned long, unsigned long);
1360 get_area
= current
->mm
->get_unmapped_area
;
1361 if (file
&& file
->f_op
&& file
->f_op
->get_unmapped_area
)
1362 get_area
= file
->f_op
->get_unmapped_area
;
1363 addr
= get_area(file
, addr
, len
, pgoff
, flags
);
1364 if (IS_ERR_VALUE(addr
))
1368 if (addr
> TASK_SIZE
- len
)
1370 if (addr
& ~PAGE_MASK
)
1372 if (file
&& is_file_hugepages(file
)) {
1374 * Check if the given range is hugepage aligned, and
1375 * can be made suitable for hugepages.
1377 ret
= prepare_hugepage_range(addr
, len
);
1380 * Ensure that a normal request is not falling in a
1381 * reserved hugepage range. For some archs like IA-64,
1382 * there is a separate region for hugepages.
1384 ret
= is_hugepage_only_range(current
->mm
, addr
, len
);
1391 EXPORT_SYMBOL(get_unmapped_area
);
1393 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1394 struct vm_area_struct
* find_vma(struct mm_struct
* mm
, unsigned long addr
)
1396 struct vm_area_struct
*vma
= NULL
;
1399 /* Check the cache first. */
1400 /* (Cache hit rate is typically around 35%.) */
1401 vma
= mm
->mmap_cache
;
1402 if (!(vma
&& vma
->vm_end
> addr
&& vma
->vm_start
<= addr
)) {
1403 struct rb_node
* rb_node
;
1405 rb_node
= mm
->mm_rb
.rb_node
;
1409 struct vm_area_struct
* vma_tmp
;
1411 vma_tmp
= rb_entry(rb_node
,
1412 struct vm_area_struct
, vm_rb
);
1414 if (vma_tmp
->vm_end
> addr
) {
1416 if (vma_tmp
->vm_start
<= addr
)
1418 rb_node
= rb_node
->rb_left
;
1420 rb_node
= rb_node
->rb_right
;
1423 mm
->mmap_cache
= vma
;
1429 EXPORT_SYMBOL(find_vma
);
1431 /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1432 struct vm_area_struct
*
1433 find_vma_prev(struct mm_struct
*mm
, unsigned long addr
,
1434 struct vm_area_struct
**pprev
)
1436 struct vm_area_struct
*vma
= NULL
, *prev
= NULL
;
1437 struct rb_node
* rb_node
;
1441 /* Guard against addr being lower than the first VMA */
1444 /* Go through the RB tree quickly. */
1445 rb_node
= mm
->mm_rb
.rb_node
;
1448 struct vm_area_struct
*vma_tmp
;
1449 vma_tmp
= rb_entry(rb_node
, struct vm_area_struct
, vm_rb
);
1451 if (addr
< vma_tmp
->vm_end
) {
1452 rb_node
= rb_node
->rb_left
;
1455 if (!prev
->vm_next
|| (addr
< prev
->vm_next
->vm_end
))
1457 rb_node
= rb_node
->rb_right
;
1463 return prev
? prev
->vm_next
: vma
;
1467 * Verify that the stack growth is acceptable and
1468 * update accounting. This is shared with both the
1469 * grow-up and grow-down cases.
1471 static int acct_stack_growth(struct vm_area_struct
* vma
, unsigned long size
, unsigned long grow
)
1473 struct mm_struct
*mm
= vma
->vm_mm
;
1474 struct rlimit
*rlim
= current
->signal
->rlim
;
1476 /* address space limit tests */
1477 if (!may_expand_vm(mm
, grow
))
1480 /* Stack limit test */
1481 if (size
> rlim
[RLIMIT_STACK
].rlim_cur
)
1484 /* mlock limit tests */
1485 if (vma
->vm_flags
& VM_LOCKED
) {
1486 unsigned long locked
;
1487 unsigned long limit
;
1488 locked
= mm
->locked_vm
+ grow
;
1489 limit
= rlim
[RLIMIT_MEMLOCK
].rlim_cur
>> PAGE_SHIFT
;
1490 if (locked
> limit
&& !capable(CAP_IPC_LOCK
))
1495 * Overcommit.. This must be the final test, as it will
1496 * update security statistics.
1498 if (security_vm_enough_memory(grow
))
1501 /* Ok, everything looks good - let it rip */
1502 mm
->total_vm
+= grow
;
1503 if (vma
->vm_flags
& VM_LOCKED
)
1504 mm
->locked_vm
+= grow
;
1505 vm_stat_account(mm
, vma
->vm_flags
, vma
->vm_file
, grow
);
1509 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1511 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1512 * vma is the last one with address > vma->vm_end. Have to extend vma.
1517 int expand_upwards(struct vm_area_struct
*vma
, unsigned long address
)
1521 if (!(vma
->vm_flags
& VM_GROWSUP
))
1525 * We must make sure the anon_vma is allocated
1526 * so that the anon_vma locking is not a noop.
1528 if (unlikely(anon_vma_prepare(vma
)))
1533 * vma->vm_start/vm_end cannot change under us because the caller
1534 * is required to hold the mmap_sem in read mode. We need the
1535 * anon_vma lock to serialize against concurrent expand_stacks.
1537 address
+= 4 + PAGE_SIZE
- 1;
1538 address
&= PAGE_MASK
;
1541 /* Somebody else might have raced and expanded it already */
1542 if (address
> vma
->vm_end
) {
1543 unsigned long size
, grow
;
1545 size
= address
- vma
->vm_start
;
1546 grow
= (address
- vma
->vm_end
) >> PAGE_SHIFT
;
1548 error
= acct_stack_growth(vma
, size
, grow
);
1550 vma
->vm_end
= address
;
1552 anon_vma_unlock(vma
);
1555 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1557 #ifdef CONFIG_STACK_GROWSUP
1558 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
1560 return expand_upwards(vma
, address
);
1563 struct vm_area_struct
*
1564 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
1566 struct vm_area_struct
*vma
, *prev
;
1569 vma
= find_vma_prev(mm
, addr
, &prev
);
1570 if (vma
&& (vma
->vm_start
<= addr
))
1572 if (!prev
|| expand_stack(prev
, addr
))
1574 if (prev
->vm_flags
& VM_LOCKED
) {
1575 make_pages_present(addr
, prev
->vm_end
);
1581 * vma is the first one with address < vma->vm_start. Have to extend vma.
1583 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
1588 * We must make sure the anon_vma is allocated
1589 * so that the anon_vma locking is not a noop.
1591 if (unlikely(anon_vma_prepare(vma
)))
1596 * vma->vm_start/vm_end cannot change under us because the caller
1597 * is required to hold the mmap_sem in read mode. We need the
1598 * anon_vma lock to serialize against concurrent expand_stacks.
1600 address
&= PAGE_MASK
;
1603 /* Somebody else might have raced and expanded it already */
1604 if (address
< vma
->vm_start
) {
1605 unsigned long size
, grow
;
1607 size
= vma
->vm_end
- address
;
1608 grow
= (vma
->vm_start
- address
) >> PAGE_SHIFT
;
1610 error
= acct_stack_growth(vma
, size
, grow
);
1612 vma
->vm_start
= address
;
1613 vma
->vm_pgoff
-= grow
;
1616 anon_vma_unlock(vma
);
1620 struct vm_area_struct
*
1621 find_extend_vma(struct mm_struct
* mm
, unsigned long addr
)
1623 struct vm_area_struct
* vma
;
1624 unsigned long start
;
1627 vma
= find_vma(mm
,addr
);
1630 if (vma
->vm_start
<= addr
)
1632 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
1634 start
= vma
->vm_start
;
1635 if (expand_stack(vma
, addr
))
1637 if (vma
->vm_flags
& VM_LOCKED
) {
1638 make_pages_present(addr
, start
);
1645 * Ok - we have the memory areas we should free on the vma list,
1646 * so release them, and do the vma updates.
1648 * Called with the mm semaphore held.
1650 static void remove_vma_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
1652 /* Update high watermark before we lower total_vm */
1653 update_hiwater_vm(mm
);
1655 long nrpages
= vma_pages(vma
);
1657 mm
->total_vm
-= nrpages
;
1658 if (vma
->vm_flags
& VM_LOCKED
)
1659 mm
->locked_vm
-= nrpages
;
1660 vm_stat_account(mm
, vma
->vm_flags
, vma
->vm_file
, -nrpages
);
1661 vma
= remove_vma(vma
);
1667 * Get rid of page table information in the indicated region.
1669 * Called with the mm semaphore held.
1671 static void unmap_region(struct mm_struct
*mm
,
1672 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
1673 unsigned long start
, unsigned long end
)
1675 struct vm_area_struct
*next
= prev
? prev
->vm_next
: mm
->mmap
;
1676 struct mmu_gather
*tlb
;
1677 unsigned long nr_accounted
= 0;
1680 tlb
= tlb_gather_mmu(mm
, 0);
1681 update_hiwater_rss(mm
);
1682 unmap_vmas(&tlb
, vma
, start
, end
, &nr_accounted
, NULL
);
1683 vm_unacct_memory(nr_accounted
);
1684 free_pgtables(&tlb
, vma
, prev
? prev
->vm_end
: FIRST_USER_ADDRESS
,
1685 next
? next
->vm_start
: 0);
1686 tlb_finish_mmu(tlb
, start
, end
);
1690 * Create a list of vma's touched by the unmap, removing them from the mm's
1691 * vma list as we go..
1694 detach_vmas_to_be_unmapped(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1695 struct vm_area_struct
*prev
, unsigned long end
)
1697 struct vm_area_struct
**insertion_point
;
1698 struct vm_area_struct
*tail_vma
= NULL
;
1701 insertion_point
= (prev
? &prev
->vm_next
: &mm
->mmap
);
1703 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
1707 } while (vma
&& vma
->vm_start
< end
);
1708 *insertion_point
= vma
;
1709 tail_vma
->vm_next
= NULL
;
1710 if (mm
->unmap_area
== arch_unmap_area
)
1711 addr
= prev
? prev
->vm_end
: mm
->mmap_base
;
1713 addr
= vma
? vma
->vm_start
: mm
->mmap_base
;
1714 mm
->unmap_area(mm
, addr
);
1715 mm
->mmap_cache
= NULL
; /* Kill the cache. */
1719 * Split a vma into two pieces at address 'addr', a new vma is allocated
1720 * either for the first part or the the tail.
1722 int split_vma(struct mm_struct
* mm
, struct vm_area_struct
* vma
,
1723 unsigned long addr
, int new_below
)
1725 struct mempolicy
*pol
;
1726 struct vm_area_struct
*new;
1728 if (is_vm_hugetlb_page(vma
) && (addr
& ~HPAGE_MASK
))
1731 if (mm
->map_count
>= sysctl_max_map_count
)
1734 new = kmem_cache_alloc(vm_area_cachep
, SLAB_KERNEL
);
1738 /* most fields are the same, copy all, and then fixup */
1744 new->vm_start
= addr
;
1745 new->vm_pgoff
+= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
);
1748 pol
= mpol_copy(vma_policy(vma
));
1750 kmem_cache_free(vm_area_cachep
, new);
1751 return PTR_ERR(pol
);
1753 vma_set_policy(new, pol
);
1756 get_file(new->vm_file
);
1758 if (new->vm_ops
&& new->vm_ops
->open
)
1759 new->vm_ops
->open(new);
1762 vma_adjust(vma
, addr
, vma
->vm_end
, vma
->vm_pgoff
+
1763 ((addr
- new->vm_start
) >> PAGE_SHIFT
), new);
1765 vma_adjust(vma
, vma
->vm_start
, addr
, vma
->vm_pgoff
, new);
1770 /* Munmap is split into 2 main parts -- this part which finds
1771 * what needs doing, and the areas themselves, which do the
1772 * work. This now handles partial unmappings.
1773 * Jeremy Fitzhardinge <jeremy@goop.org>
1775 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
)
1778 struct vm_area_struct
*vma
, *prev
, *last
;
1780 if ((start
& ~PAGE_MASK
) || start
> TASK_SIZE
|| len
> TASK_SIZE
-start
)
1783 if ((len
= PAGE_ALIGN(len
)) == 0)
1786 /* Find the first overlapping VMA */
1787 vma
= find_vma_prev(mm
, start
, &prev
);
1790 /* we have start < vma->vm_end */
1792 /* if it doesn't overlap, we have nothing.. */
1794 if (vma
->vm_start
>= end
)
1798 * If we need to split any vma, do it now to save pain later.
1800 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1801 * unmapped vm_area_struct will remain in use: so lower split_vma
1802 * places tmp vma above, and higher split_vma places tmp vma below.
1804 if (start
> vma
->vm_start
) {
1805 int error
= split_vma(mm
, vma
, start
, 0);
1811 /* Does it split the last one? */
1812 last
= find_vma(mm
, end
);
1813 if (last
&& end
> last
->vm_start
) {
1814 int error
= split_vma(mm
, last
, end
, 1);
1818 vma
= prev
? prev
->vm_next
: mm
->mmap
;
1821 * Remove the vma's, and unmap the actual pages
1823 detach_vmas_to_be_unmapped(mm
, vma
, prev
, end
);
1824 unmap_region(mm
, vma
, prev
, start
, end
);
1826 /* Fix up all other VM information */
1827 remove_vma_list(mm
, vma
);
1832 EXPORT_SYMBOL(do_munmap
);
1834 asmlinkage
long sys_munmap(unsigned long addr
, size_t len
)
1837 struct mm_struct
*mm
= current
->mm
;
1839 profile_munmap(addr
);
1841 down_write(&mm
->mmap_sem
);
1842 ret
= do_munmap(mm
, addr
, len
);
1843 up_write(&mm
->mmap_sem
);
1847 static inline void verify_mm_writelocked(struct mm_struct
*mm
)
1849 #ifdef CONFIG_DEBUG_VM
1850 if (unlikely(down_read_trylock(&mm
->mmap_sem
))) {
1852 up_read(&mm
->mmap_sem
);
1858 * this is really a simplified "do_mmap". it only handles
1859 * anonymous maps. eventually we may be able to do some
1860 * brk-specific accounting here.
1862 unsigned long do_brk(unsigned long addr
, unsigned long len
)
1864 struct mm_struct
* mm
= current
->mm
;
1865 struct vm_area_struct
* vma
, * prev
;
1866 unsigned long flags
;
1867 struct rb_node
** rb_link
, * rb_parent
;
1868 pgoff_t pgoff
= addr
>> PAGE_SHIFT
;
1870 len
= PAGE_ALIGN(len
);
1874 if ((addr
+ len
) > TASK_SIZE
|| (addr
+ len
) < addr
)
1880 if (mm
->def_flags
& VM_LOCKED
) {
1881 unsigned long locked
, lock_limit
;
1882 locked
= len
>> PAGE_SHIFT
;
1883 locked
+= mm
->locked_vm
;
1884 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1885 lock_limit
>>= PAGE_SHIFT
;
1886 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
1891 * mm->mmap_sem is required to protect against another thread
1892 * changing the mappings in case we sleep.
1894 verify_mm_writelocked(mm
);
1897 * Clear old maps. this also does some error checking for us
1900 vma
= find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
1901 if (vma
&& vma
->vm_start
< addr
+ len
) {
1902 if (do_munmap(mm
, addr
, len
))
1907 /* Check against address space limits *after* clearing old maps... */
1908 if (!may_expand_vm(mm
, len
>> PAGE_SHIFT
))
1911 if (mm
->map_count
> sysctl_max_map_count
)
1914 if (security_vm_enough_memory(len
>> PAGE_SHIFT
))
1917 flags
= VM_DATA_DEFAULT_FLAGS
| VM_ACCOUNT
| mm
->def_flags
;
1919 /* Can we just expand an old private anonymous mapping? */
1920 if (vma_merge(mm
, prev
, addr
, addr
+ len
, flags
,
1921 NULL
, NULL
, pgoff
, NULL
))
1925 * create a vma struct for an anonymous mapping
1927 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1929 vm_unacct_memory(len
>> PAGE_SHIFT
);
1934 vma
->vm_start
= addr
;
1935 vma
->vm_end
= addr
+ len
;
1936 vma
->vm_pgoff
= pgoff
;
1937 vma
->vm_flags
= flags
;
1938 vma
->vm_page_prot
= protection_map
[flags
&
1939 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)];
1940 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
1942 mm
->total_vm
+= len
>> PAGE_SHIFT
;
1943 if (flags
& VM_LOCKED
) {
1944 mm
->locked_vm
+= len
>> PAGE_SHIFT
;
1945 make_pages_present(addr
, addr
+ len
);
1950 EXPORT_SYMBOL(do_brk
);
1952 /* Release all mmaps. */
1953 void exit_mmap(struct mm_struct
*mm
)
1955 struct mmu_gather
*tlb
;
1956 struct vm_area_struct
*vma
= mm
->mmap
;
1957 unsigned long nr_accounted
= 0;
1962 tlb
= tlb_gather_mmu(mm
, 1);
1963 /* Don't update_hiwater_rss(mm) here, do_exit already did */
1964 /* Use -1 here to ensure all VMAs in the mm are unmapped */
1965 end
= unmap_vmas(&tlb
, vma
, 0, -1, &nr_accounted
, NULL
);
1966 vm_unacct_memory(nr_accounted
);
1967 free_pgtables(&tlb
, vma
, FIRST_USER_ADDRESS
, 0);
1968 tlb_finish_mmu(tlb
, 0, end
);
1971 * Walk the list again, actually closing and freeing it,
1972 * with preemption enabled, without holding any MM locks.
1975 vma
= remove_vma(vma
);
1977 BUG_ON(mm
->nr_ptes
> (FIRST_USER_ADDRESS
+PMD_SIZE
-1)>>PMD_SHIFT
);
1980 /* Insert vm structure into process list sorted by address
1981 * and into the inode's i_mmap tree. If vm_file is non-NULL
1982 * then i_mmap_lock is taken here.
1984 int insert_vm_struct(struct mm_struct
* mm
, struct vm_area_struct
* vma
)
1986 struct vm_area_struct
* __vma
, * prev
;
1987 struct rb_node
** rb_link
, * rb_parent
;
1990 * The vm_pgoff of a purely anonymous vma should be irrelevant
1991 * until its first write fault, when page's anon_vma and index
1992 * are set. But now set the vm_pgoff it will almost certainly
1993 * end up with (unless mremap moves it elsewhere before that
1994 * first wfault), so /proc/pid/maps tells a consistent story.
1996 * By setting it to reflect the virtual start address of the
1997 * vma, merges and splits can happen in a seamless way, just
1998 * using the existing file pgoff checks and manipulations.
1999 * Similarly in do_mmap_pgoff and in do_brk.
2001 if (!vma
->vm_file
) {
2002 BUG_ON(vma
->anon_vma
);
2003 vma
->vm_pgoff
= vma
->vm_start
>> PAGE_SHIFT
;
2005 __vma
= find_vma_prepare(mm
,vma
->vm_start
,&prev
,&rb_link
,&rb_parent
);
2006 if (__vma
&& __vma
->vm_start
< vma
->vm_end
)
2008 if ((vma
->vm_flags
& VM_ACCOUNT
) &&
2009 security_vm_enough_memory(vma_pages(vma
)))
2011 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
2016 * Copy the vma structure to a new location in the same mm,
2017 * prior to moving page table entries, to effect an mremap move.
2019 struct vm_area_struct
*copy_vma(struct vm_area_struct
**vmap
,
2020 unsigned long addr
, unsigned long len
, pgoff_t pgoff
)
2022 struct vm_area_struct
*vma
= *vmap
;
2023 unsigned long vma_start
= vma
->vm_start
;
2024 struct mm_struct
*mm
= vma
->vm_mm
;
2025 struct vm_area_struct
*new_vma
, *prev
;
2026 struct rb_node
**rb_link
, *rb_parent
;
2027 struct mempolicy
*pol
;
2030 * If anonymous vma has not yet been faulted, update new pgoff
2031 * to match new location, to increase its chance of merging.
2033 if (!vma
->vm_file
&& !vma
->anon_vma
)
2034 pgoff
= addr
>> PAGE_SHIFT
;
2036 find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
2037 new_vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vma
->vm_flags
,
2038 vma
->anon_vma
, vma
->vm_file
, pgoff
, vma_policy(vma
));
2041 * Source vma may have been merged into new_vma
2043 if (vma_start
>= new_vma
->vm_start
&&
2044 vma_start
< new_vma
->vm_end
)
2047 new_vma
= kmem_cache_alloc(vm_area_cachep
, SLAB_KERNEL
);
2050 pol
= mpol_copy(vma_policy(vma
));
2052 kmem_cache_free(vm_area_cachep
, new_vma
);
2055 vma_set_policy(new_vma
, pol
);
2056 new_vma
->vm_start
= addr
;
2057 new_vma
->vm_end
= addr
+ len
;
2058 new_vma
->vm_pgoff
= pgoff
;
2059 if (new_vma
->vm_file
)
2060 get_file(new_vma
->vm_file
);
2061 if (new_vma
->vm_ops
&& new_vma
->vm_ops
->open
)
2062 new_vma
->vm_ops
->open(new_vma
);
2063 vma_link(mm
, new_vma
, prev
, rb_link
, rb_parent
);
2070 * Return true if the calling process may expand its vm space by the passed
2073 int may_expand_vm(struct mm_struct
*mm
, unsigned long npages
)
2075 unsigned long cur
= mm
->total_vm
; /* pages */
2078 lim
= current
->signal
->rlim
[RLIMIT_AS
].rlim_cur
>> PAGE_SHIFT
;
2080 if (cur
+ npages
> lim
)