6 * Address space accounting code <alan@redhat.com>
9 #include <linux/slab.h>
10 #include <linux/backing-dev.h>
12 #include <linux/shm.h>
13 #include <linux/mman.h>
14 #include <linux/pagemap.h>
15 #include <linux/swap.h>
16 #include <linux/syscalls.h>
17 #include <linux/capability.h>
18 #include <linux/init.h>
19 #include <linux/file.h>
21 #include <linux/personality.h>
22 #include <linux/security.h>
23 #include <linux/hugetlb.h>
24 #include <linux/profile.h>
25 #include <linux/module.h>
26 #include <linux/mount.h>
27 #include <linux/mempolicy.h>
28 #include <linux/rmap.h>
30 #include <asm/uaccess.h>
31 #include <asm/cacheflush.h>
33 #include <asm/mmu_context.h>
35 #ifndef arch_mmap_check
36 #define arch_mmap_check(addr, len, flags) (0)
39 #ifndef arch_rebalance_pgtables
40 #define arch_rebalance_pgtables(addr, len) (addr)
43 static void unmap_region(struct mm_struct
*mm
,
44 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
45 unsigned long start
, unsigned long end
);
48 * WARNING: the debugging will use recursive algorithms so never enable this
49 * unless you know what you are doing.
53 /* description of effects of mapping type and prot in current implementation.
54 * this is due to the limited x86 page protection hardware. The expected
55 * behavior is in parens:
58 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
59 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
60 * w: (no) no w: (no) no w: (yes) yes w: (no) no
61 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
63 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
64 * w: (no) no w: (no) no w: (copy) copy w: (no) no
65 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
68 pgprot_t protection_map
[16] = {
69 __P000
, __P001
, __P010
, __P011
, __P100
, __P101
, __P110
, __P111
,
70 __S000
, __S001
, __S010
, __S011
, __S100
, __S101
, __S110
, __S111
73 pgprot_t
vm_get_page_prot(unsigned long vm_flags
)
75 return protection_map
[vm_flags
&
76 (VM_READ
|VM_WRITE
|VM_EXEC
|VM_SHARED
)];
78 EXPORT_SYMBOL(vm_get_page_prot
);
80 int sysctl_overcommit_memory
= OVERCOMMIT_GUESS
; /* heuristic overcommit */
81 int sysctl_overcommit_ratio
= 50; /* default is 50% */
82 int sysctl_max_map_count __read_mostly
= DEFAULT_MAX_MAP_COUNT
;
83 atomic_t vm_committed_space
= ATOMIC_INIT(0);
86 * Check that a process has enough memory to allocate a new virtual
87 * mapping. 0 means there is enough memory for the allocation to
88 * succeed and -ENOMEM implies there is not.
90 * We currently support three overcommit policies, which are set via the
91 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
93 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
94 * Additional code 2002 Jul 20 by Robert Love.
96 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
98 * Note this is a helper function intended to be used by LSMs which
99 * wish to use this logic.
101 int __vm_enough_memory(struct mm_struct
*mm
, long pages
, int cap_sys_admin
)
103 unsigned long free
, allowed
;
105 vm_acct_memory(pages
);
108 * Sometimes we want to use more memory than we have
110 if (sysctl_overcommit_memory
== OVERCOMMIT_ALWAYS
)
113 if (sysctl_overcommit_memory
== OVERCOMMIT_GUESS
) {
116 free
= global_page_state(NR_FILE_PAGES
);
117 free
+= nr_swap_pages
;
120 * Any slabs which are created with the
121 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
122 * which are reclaimable, under pressure. The dentry
123 * cache and most inode caches should fall into this
125 free
+= global_page_state(NR_SLAB_RECLAIMABLE
);
128 * Leave the last 3% for root
137 * nr_free_pages() is very expensive on large systems,
138 * only call if we're about to fail.
143 * Leave reserved pages. The pages are not for anonymous pages.
145 if (n
<= totalreserve_pages
)
148 n
-= totalreserve_pages
;
151 * Leave the last 3% for root
163 allowed
= (totalram_pages
- hugetlb_total_pages())
164 * sysctl_overcommit_ratio
/ 100;
166 * Leave the last 3% for root
169 allowed
-= allowed
/ 32;
170 allowed
+= total_swap_pages
;
172 /* Don't let a single process grow too big:
173 leave 3% of the size of this process for other processes */
174 allowed
-= mm
->total_vm
/ 32;
177 * cast `allowed' as a signed long because vm_committed_space
178 * sometimes has a negative value
180 if (atomic_read(&vm_committed_space
) < (long)allowed
)
183 vm_unacct_memory(pages
);
189 * Requires inode->i_mapping->i_mmap_lock
191 static void __remove_shared_vm_struct(struct vm_area_struct
*vma
,
192 struct file
*file
, struct address_space
*mapping
)
194 if (vma
->vm_flags
& VM_DENYWRITE
)
195 atomic_inc(&file
->f_path
.dentry
->d_inode
->i_writecount
);
196 if (vma
->vm_flags
& VM_SHARED
)
197 mapping
->i_mmap_writable
--;
199 flush_dcache_mmap_lock(mapping
);
200 if (unlikely(vma
->vm_flags
& VM_NONLINEAR
))
201 list_del_init(&vma
->shared
.vm_set
.list
);
203 vma_prio_tree_remove(vma
, &mapping
->i_mmap
);
204 flush_dcache_mmap_unlock(mapping
);
208 * Unlink a file-based vm structure from its prio_tree, to hide
209 * vma from rmap and vmtruncate before freeing its page tables.
211 void unlink_file_vma(struct vm_area_struct
*vma
)
213 struct file
*file
= vma
->vm_file
;
216 struct address_space
*mapping
= file
->f_mapping
;
217 spin_lock(&mapping
->i_mmap_lock
);
218 __remove_shared_vm_struct(vma
, file
, mapping
);
219 spin_unlock(&mapping
->i_mmap_lock
);
224 * Close a vm structure and free it, returning the next.
226 static struct vm_area_struct
*remove_vma(struct vm_area_struct
*vma
)
228 struct vm_area_struct
*next
= vma
->vm_next
;
231 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
232 vma
->vm_ops
->close(vma
);
235 mpol_free(vma_policy(vma
));
236 kmem_cache_free(vm_area_cachep
, vma
);
240 asmlinkage
unsigned long sys_brk(unsigned long brk
)
242 unsigned long rlim
, retval
;
243 unsigned long newbrk
, oldbrk
;
244 struct mm_struct
*mm
= current
->mm
;
246 down_write(&mm
->mmap_sem
);
248 if (brk
< mm
->start_brk
)
252 * Check against rlimit here. If this check is done later after the test
253 * of oldbrk with newbrk then it can escape the test and let the data
254 * segment grow beyond its set limit the in case where the limit is
255 * not page aligned -Ram Gupta
257 rlim
= current
->signal
->rlim
[RLIMIT_DATA
].rlim_cur
;
258 if (rlim
< RLIM_INFINITY
&& (brk
- mm
->start_brk
) +
259 (mm
->end_data
- mm
->start_data
) > rlim
)
262 newbrk
= PAGE_ALIGN(brk
);
263 oldbrk
= PAGE_ALIGN(mm
->brk
);
264 if (oldbrk
== newbrk
)
267 /* Always allow shrinking brk. */
268 if (brk
<= mm
->brk
) {
269 if (!do_munmap(mm
, newbrk
, oldbrk
-newbrk
))
274 /* Check against existing mmap mappings. */
275 if (find_vma_intersection(mm
, oldbrk
, newbrk
+PAGE_SIZE
))
278 /* Ok, looks good - let it rip. */
279 if (do_brk(oldbrk
, newbrk
-oldbrk
) != oldbrk
)
285 up_write(&mm
->mmap_sem
);
290 static int browse_rb(struct rb_root
*root
)
293 struct rb_node
*nd
, *pn
= NULL
;
294 unsigned long prev
= 0, pend
= 0;
296 for (nd
= rb_first(root
); nd
; nd
= rb_next(nd
)) {
297 struct vm_area_struct
*vma
;
298 vma
= rb_entry(nd
, struct vm_area_struct
, vm_rb
);
299 if (vma
->vm_start
< prev
)
300 printk("vm_start %lx prev %lx\n", vma
->vm_start
, prev
), i
= -1;
301 if (vma
->vm_start
< pend
)
302 printk("vm_start %lx pend %lx\n", vma
->vm_start
, pend
);
303 if (vma
->vm_start
> vma
->vm_end
)
304 printk("vm_end %lx < vm_start %lx\n", vma
->vm_end
, vma
->vm_start
);
307 prev
= vma
->vm_start
;
311 for (nd
= pn
; nd
; nd
= rb_prev(nd
)) {
315 printk("backwards %d, forwards %d\n", j
, i
), i
= 0;
319 void validate_mm(struct mm_struct
*mm
)
323 struct vm_area_struct
*tmp
= mm
->mmap
;
328 if (i
!= mm
->map_count
)
329 printk("map_count %d vm_next %d\n", mm
->map_count
, i
), bug
= 1;
330 i
= browse_rb(&mm
->mm_rb
);
331 if (i
!= mm
->map_count
)
332 printk("map_count %d rb %d\n", mm
->map_count
, i
), bug
= 1;
336 #define validate_mm(mm) do { } while (0)
339 static struct vm_area_struct
*
340 find_vma_prepare(struct mm_struct
*mm
, unsigned long addr
,
341 struct vm_area_struct
**pprev
, struct rb_node
***rb_link
,
342 struct rb_node
** rb_parent
)
344 struct vm_area_struct
* vma
;
345 struct rb_node
** __rb_link
, * __rb_parent
, * rb_prev
;
347 __rb_link
= &mm
->mm_rb
.rb_node
;
348 rb_prev
= __rb_parent
= NULL
;
352 struct vm_area_struct
*vma_tmp
;
354 __rb_parent
= *__rb_link
;
355 vma_tmp
= rb_entry(__rb_parent
, struct vm_area_struct
, vm_rb
);
357 if (vma_tmp
->vm_end
> addr
) {
359 if (vma_tmp
->vm_start
<= addr
)
361 __rb_link
= &__rb_parent
->rb_left
;
363 rb_prev
= __rb_parent
;
364 __rb_link
= &__rb_parent
->rb_right
;
370 *pprev
= rb_entry(rb_prev
, struct vm_area_struct
, vm_rb
);
371 *rb_link
= __rb_link
;
372 *rb_parent
= __rb_parent
;
377 __vma_link_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
378 struct vm_area_struct
*prev
, struct rb_node
*rb_parent
)
381 vma
->vm_next
= prev
->vm_next
;
386 vma
->vm_next
= rb_entry(rb_parent
,
387 struct vm_area_struct
, vm_rb
);
393 void __vma_link_rb(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
394 struct rb_node
**rb_link
, struct rb_node
*rb_parent
)
396 rb_link_node(&vma
->vm_rb
, rb_parent
, rb_link
);
397 rb_insert_color(&vma
->vm_rb
, &mm
->mm_rb
);
400 static inline void __vma_link_file(struct vm_area_struct
*vma
)
406 struct address_space
*mapping
= file
->f_mapping
;
408 if (vma
->vm_flags
& VM_DENYWRITE
)
409 atomic_dec(&file
->f_path
.dentry
->d_inode
->i_writecount
);
410 if (vma
->vm_flags
& VM_SHARED
)
411 mapping
->i_mmap_writable
++;
413 flush_dcache_mmap_lock(mapping
);
414 if (unlikely(vma
->vm_flags
& VM_NONLINEAR
))
415 vma_nonlinear_insert(vma
, &mapping
->i_mmap_nonlinear
);
417 vma_prio_tree_insert(vma
, &mapping
->i_mmap
);
418 flush_dcache_mmap_unlock(mapping
);
423 __vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
424 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
425 struct rb_node
*rb_parent
)
427 __vma_link_list(mm
, vma
, prev
, rb_parent
);
428 __vma_link_rb(mm
, vma
, rb_link
, rb_parent
);
429 __anon_vma_link(vma
);
432 static void vma_link(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
433 struct vm_area_struct
*prev
, struct rb_node
**rb_link
,
434 struct rb_node
*rb_parent
)
436 struct address_space
*mapping
= NULL
;
439 mapping
= vma
->vm_file
->f_mapping
;
442 spin_lock(&mapping
->i_mmap_lock
);
443 vma
->vm_truncate_count
= mapping
->truncate_count
;
447 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
448 __vma_link_file(vma
);
450 anon_vma_unlock(vma
);
452 spin_unlock(&mapping
->i_mmap_lock
);
459 * Helper for vma_adjust in the split_vma insert case:
460 * insert vm structure into list and rbtree and anon_vma,
461 * but it has already been inserted into prio_tree earlier.
464 __insert_vm_struct(struct mm_struct
* mm
, struct vm_area_struct
* vma
)
466 struct vm_area_struct
* __vma
, * prev
;
467 struct rb_node
** rb_link
, * rb_parent
;
469 __vma
= find_vma_prepare(mm
, vma
->vm_start
,&prev
, &rb_link
, &rb_parent
);
470 BUG_ON(__vma
&& __vma
->vm_start
< vma
->vm_end
);
471 __vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
476 __vma_unlink(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
477 struct vm_area_struct
*prev
)
479 prev
->vm_next
= vma
->vm_next
;
480 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
481 if (mm
->mmap_cache
== vma
)
482 mm
->mmap_cache
= prev
;
486 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
487 * is already present in an i_mmap tree without adjusting the tree.
488 * The following helper function should be used when such adjustments
489 * are necessary. The "insert" vma (if any) is to be inserted
490 * before we drop the necessary locks.
492 void vma_adjust(struct vm_area_struct
*vma
, unsigned long start
,
493 unsigned long end
, pgoff_t pgoff
, struct vm_area_struct
*insert
)
495 struct mm_struct
*mm
= vma
->vm_mm
;
496 struct vm_area_struct
*next
= vma
->vm_next
;
497 struct vm_area_struct
*importer
= NULL
;
498 struct address_space
*mapping
= NULL
;
499 struct prio_tree_root
*root
= NULL
;
500 struct file
*file
= vma
->vm_file
;
501 struct anon_vma
*anon_vma
= NULL
;
502 long adjust_next
= 0;
505 if (next
&& !insert
) {
506 if (end
>= next
->vm_end
) {
508 * vma expands, overlapping all the next, and
509 * perhaps the one after too (mprotect case 6).
511 again
: remove_next
= 1 + (end
> next
->vm_end
);
513 anon_vma
= next
->anon_vma
;
515 } else if (end
> next
->vm_start
) {
517 * vma expands, overlapping part of the next:
518 * mprotect case 5 shifting the boundary up.
520 adjust_next
= (end
- next
->vm_start
) >> PAGE_SHIFT
;
521 anon_vma
= next
->anon_vma
;
523 } else if (end
< vma
->vm_end
) {
525 * vma shrinks, and !insert tells it's not
526 * split_vma inserting another: so it must be
527 * mprotect case 4 shifting the boundary down.
529 adjust_next
= - ((vma
->vm_end
- end
) >> PAGE_SHIFT
);
530 anon_vma
= next
->anon_vma
;
536 mapping
= file
->f_mapping
;
537 if (!(vma
->vm_flags
& VM_NONLINEAR
))
538 root
= &mapping
->i_mmap
;
539 spin_lock(&mapping
->i_mmap_lock
);
541 vma
->vm_truncate_count
!= next
->vm_truncate_count
) {
543 * unmap_mapping_range might be in progress:
544 * ensure that the expanding vma is rescanned.
546 importer
->vm_truncate_count
= 0;
549 insert
->vm_truncate_count
= vma
->vm_truncate_count
;
551 * Put into prio_tree now, so instantiated pages
552 * are visible to arm/parisc __flush_dcache_page
553 * throughout; but we cannot insert into address
554 * space until vma start or end is updated.
556 __vma_link_file(insert
);
561 * When changing only vma->vm_end, we don't really need
562 * anon_vma lock: but is that case worth optimizing out?
565 anon_vma
= vma
->anon_vma
;
567 spin_lock(&anon_vma
->lock
);
569 * Easily overlooked: when mprotect shifts the boundary,
570 * make sure the expanding vma has anon_vma set if the
571 * shrinking vma had, to cover any anon pages imported.
573 if (importer
&& !importer
->anon_vma
) {
574 importer
->anon_vma
= anon_vma
;
575 __anon_vma_link(importer
);
580 flush_dcache_mmap_lock(mapping
);
581 vma_prio_tree_remove(vma
, root
);
583 vma_prio_tree_remove(next
, root
);
586 vma
->vm_start
= start
;
588 vma
->vm_pgoff
= pgoff
;
590 next
->vm_start
+= adjust_next
<< PAGE_SHIFT
;
591 next
->vm_pgoff
+= adjust_next
;
596 vma_prio_tree_insert(next
, root
);
597 vma_prio_tree_insert(vma
, root
);
598 flush_dcache_mmap_unlock(mapping
);
603 * vma_merge has merged next into vma, and needs
604 * us to remove next before dropping the locks.
606 __vma_unlink(mm
, next
, vma
);
608 __remove_shared_vm_struct(next
, file
, mapping
);
610 __anon_vma_merge(vma
, next
);
613 * split_vma has split insert from vma, and needs
614 * us to insert it before dropping the locks
615 * (it may either follow vma or precede it).
617 __insert_vm_struct(mm
, insert
);
621 spin_unlock(&anon_vma
->lock
);
623 spin_unlock(&mapping
->i_mmap_lock
);
629 mpol_free(vma_policy(next
));
630 kmem_cache_free(vm_area_cachep
, next
);
632 * In mprotect's case 6 (see comments on vma_merge),
633 * we must remove another next too. It would clutter
634 * up the code too much to do both in one go.
636 if (remove_next
== 2) {
646 * If the vma has a ->close operation then the driver probably needs to release
647 * per-vma resources, so we don't attempt to merge those.
649 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
651 static inline int is_mergeable_vma(struct vm_area_struct
*vma
,
652 struct file
*file
, unsigned long vm_flags
)
654 if (vma
->vm_flags
!= vm_flags
)
656 if (vma
->vm_file
!= file
)
658 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
663 static inline int is_mergeable_anon_vma(struct anon_vma
*anon_vma1
,
664 struct anon_vma
*anon_vma2
)
666 return !anon_vma1
|| !anon_vma2
|| (anon_vma1
== anon_vma2
);
670 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
671 * in front of (at a lower virtual address and file offset than) the vma.
673 * We cannot merge two vmas if they have differently assigned (non-NULL)
674 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
676 * We don't check here for the merged mmap wrapping around the end of pagecache
677 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
678 * wrap, nor mmaps which cover the final page at index -1UL.
681 can_vma_merge_before(struct vm_area_struct
*vma
, unsigned long vm_flags
,
682 struct anon_vma
*anon_vma
, struct file
*file
, pgoff_t vm_pgoff
)
684 if (is_mergeable_vma(vma
, file
, vm_flags
) &&
685 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
)) {
686 if (vma
->vm_pgoff
== vm_pgoff
)
693 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
694 * beyond (at a higher virtual address and file offset than) the vma.
696 * We cannot merge two vmas if they have differently assigned (non-NULL)
697 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
700 can_vma_merge_after(struct vm_area_struct
*vma
, unsigned long vm_flags
,
701 struct anon_vma
*anon_vma
, struct file
*file
, pgoff_t vm_pgoff
)
703 if (is_mergeable_vma(vma
, file
, vm_flags
) &&
704 is_mergeable_anon_vma(anon_vma
, vma
->anon_vma
)) {
706 vm_pglen
= (vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
;
707 if (vma
->vm_pgoff
+ vm_pglen
== vm_pgoff
)
714 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
715 * whether that can be merged with its predecessor or its successor.
716 * Or both (it neatly fills a hole).
718 * In most cases - when called for mmap, brk or mremap - [addr,end) is
719 * certain not to be mapped by the time vma_merge is called; but when
720 * called for mprotect, it is certain to be already mapped (either at
721 * an offset within prev, or at the start of next), and the flags of
722 * this area are about to be changed to vm_flags - and the no-change
723 * case has already been eliminated.
725 * The following mprotect cases have to be considered, where AAAA is
726 * the area passed down from mprotect_fixup, never extending beyond one
727 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
729 * AAAA AAAA AAAA AAAA
730 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
731 * cannot merge might become might become might become
732 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
733 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
734 * mremap move: PPPPNNNNNNNN 8
736 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
737 * might become case 1 below case 2 below case 3 below
739 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
740 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
742 struct vm_area_struct
*vma_merge(struct mm_struct
*mm
,
743 struct vm_area_struct
*prev
, unsigned long addr
,
744 unsigned long end
, unsigned long vm_flags
,
745 struct anon_vma
*anon_vma
, struct file
*file
,
746 pgoff_t pgoff
, struct mempolicy
*policy
)
748 pgoff_t pglen
= (end
- addr
) >> PAGE_SHIFT
;
749 struct vm_area_struct
*area
, *next
;
752 * We later require that vma->vm_flags == vm_flags,
753 * so this tests vma->vm_flags & VM_SPECIAL, too.
755 if (vm_flags
& VM_SPECIAL
)
759 next
= prev
->vm_next
;
763 if (next
&& next
->vm_end
== end
) /* cases 6, 7, 8 */
764 next
= next
->vm_next
;
767 * Can it merge with the predecessor?
769 if (prev
&& prev
->vm_end
== addr
&&
770 mpol_equal(vma_policy(prev
), policy
) &&
771 can_vma_merge_after(prev
, vm_flags
,
772 anon_vma
, file
, pgoff
)) {
774 * OK, it can. Can we now merge in the successor as well?
776 if (next
&& end
== next
->vm_start
&&
777 mpol_equal(policy
, vma_policy(next
)) &&
778 can_vma_merge_before(next
, vm_flags
,
779 anon_vma
, file
, pgoff
+pglen
) &&
780 is_mergeable_anon_vma(prev
->anon_vma
,
783 vma_adjust(prev
, prev
->vm_start
,
784 next
->vm_end
, prev
->vm_pgoff
, NULL
);
785 } else /* cases 2, 5, 7 */
786 vma_adjust(prev
, prev
->vm_start
,
787 end
, prev
->vm_pgoff
, NULL
);
792 * Can this new request be merged in front of next?
794 if (next
&& end
== next
->vm_start
&&
795 mpol_equal(policy
, vma_policy(next
)) &&
796 can_vma_merge_before(next
, vm_flags
,
797 anon_vma
, file
, pgoff
+pglen
)) {
798 if (prev
&& addr
< prev
->vm_end
) /* case 4 */
799 vma_adjust(prev
, prev
->vm_start
,
800 addr
, prev
->vm_pgoff
, NULL
);
801 else /* cases 3, 8 */
802 vma_adjust(area
, addr
, next
->vm_end
,
803 next
->vm_pgoff
- pglen
, NULL
);
811 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
812 * neighbouring vmas for a suitable anon_vma, before it goes off
813 * to allocate a new anon_vma. It checks because a repetitive
814 * sequence of mprotects and faults may otherwise lead to distinct
815 * anon_vmas being allocated, preventing vma merge in subsequent
818 struct anon_vma
*find_mergeable_anon_vma(struct vm_area_struct
*vma
)
820 struct vm_area_struct
*near
;
821 unsigned long vm_flags
;
828 * Since only mprotect tries to remerge vmas, match flags
829 * which might be mprotected into each other later on.
830 * Neither mlock nor madvise tries to remerge at present,
831 * so leave their flags as obstructing a merge.
833 vm_flags
= vma
->vm_flags
& ~(VM_READ
|VM_WRITE
|VM_EXEC
);
834 vm_flags
|= near
->vm_flags
& (VM_READ
|VM_WRITE
|VM_EXEC
);
836 if (near
->anon_vma
&& vma
->vm_end
== near
->vm_start
&&
837 mpol_equal(vma_policy(vma
), vma_policy(near
)) &&
838 can_vma_merge_before(near
, vm_flags
,
839 NULL
, vma
->vm_file
, vma
->vm_pgoff
+
840 ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
)))
841 return near
->anon_vma
;
844 * It is potentially slow to have to call find_vma_prev here.
845 * But it's only on the first write fault on the vma, not
846 * every time, and we could devise a way to avoid it later
847 * (e.g. stash info in next's anon_vma_node when assigning
848 * an anon_vma, or when trying vma_merge). Another time.
850 BUG_ON(find_vma_prev(vma
->vm_mm
, vma
->vm_start
, &near
) != vma
);
854 vm_flags
= vma
->vm_flags
& ~(VM_READ
|VM_WRITE
|VM_EXEC
);
855 vm_flags
|= near
->vm_flags
& (VM_READ
|VM_WRITE
|VM_EXEC
);
857 if (near
->anon_vma
&& near
->vm_end
== vma
->vm_start
&&
858 mpol_equal(vma_policy(near
), vma_policy(vma
)) &&
859 can_vma_merge_after(near
, vm_flags
,
860 NULL
, vma
->vm_file
, vma
->vm_pgoff
))
861 return near
->anon_vma
;
864 * There's no absolute need to look only at touching neighbours:
865 * we could search further afield for "compatible" anon_vmas.
866 * But it would probably just be a waste of time searching,
867 * or lead to too many vmas hanging off the same anon_vma.
868 * We're trying to allow mprotect remerging later on,
869 * not trying to minimize memory used for anon_vmas.
874 #ifdef CONFIG_PROC_FS
875 void vm_stat_account(struct mm_struct
*mm
, unsigned long flags
,
876 struct file
*file
, long pages
)
878 const unsigned long stack_flags
879 = VM_STACK_FLAGS
& (VM_GROWSUP
|VM_GROWSDOWN
);
882 mm
->shared_vm
+= pages
;
883 if ((flags
& (VM_EXEC
|VM_WRITE
)) == VM_EXEC
)
884 mm
->exec_vm
+= pages
;
885 } else if (flags
& stack_flags
)
886 mm
->stack_vm
+= pages
;
887 if (flags
& (VM_RESERVED
|VM_IO
))
888 mm
->reserved_vm
+= pages
;
890 #endif /* CONFIG_PROC_FS */
893 * The caller must hold down_write(current->mm->mmap_sem).
896 unsigned long do_mmap_pgoff(struct file
* file
, unsigned long addr
,
897 unsigned long len
, unsigned long prot
,
898 unsigned long flags
, unsigned long pgoff
)
900 struct mm_struct
* mm
= current
->mm
;
902 unsigned int vm_flags
;
905 unsigned long reqprot
= prot
;
908 * Does the application expect PROT_READ to imply PROT_EXEC?
910 * (the exception is when the underlying filesystem is noexec
911 * mounted, in which case we dont add PROT_EXEC.)
913 if ((prot
& PROT_READ
) && (current
->personality
& READ_IMPLIES_EXEC
))
914 if (!(file
&& (file
->f_path
.mnt
->mnt_flags
& MNT_NOEXEC
)))
920 if (!(flags
& MAP_FIXED
))
921 addr
= round_hint_to_min(addr
);
923 error
= arch_mmap_check(addr
, len
, flags
);
927 /* Careful about overflows.. */
928 len
= PAGE_ALIGN(len
);
929 if (!len
|| len
> TASK_SIZE
)
932 /* offset overflow? */
933 if ((pgoff
+ (len
>> PAGE_SHIFT
)) < pgoff
)
936 /* Too many mappings? */
937 if (mm
->map_count
> sysctl_max_map_count
)
940 /* Obtain the address to map to. we verify (or select) it and ensure
941 * that it represents a valid section of the address space.
943 addr
= get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
944 if (addr
& ~PAGE_MASK
)
947 /* Do simple checking here so the lower-level routines won't have
948 * to. we assume access permissions have been handled by the open
949 * of the memory object, so we don't do any here.
951 vm_flags
= calc_vm_prot_bits(prot
) | calc_vm_flag_bits(flags
) |
952 mm
->def_flags
| VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
954 if (flags
& MAP_LOCKED
) {
957 vm_flags
|= VM_LOCKED
;
959 /* mlock MCL_FUTURE? */
960 if (vm_flags
& VM_LOCKED
) {
961 unsigned long locked
, lock_limit
;
962 locked
= len
>> PAGE_SHIFT
;
963 locked
+= mm
->locked_vm
;
964 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
965 lock_limit
>>= PAGE_SHIFT
;
966 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
970 inode
= file
? file
->f_path
.dentry
->d_inode
: NULL
;
973 switch (flags
& MAP_TYPE
) {
975 if ((prot
&PROT_WRITE
) && !(file
->f_mode
&FMODE_WRITE
))
979 * Make sure we don't allow writing to an append-only
982 if (IS_APPEND(inode
) && (file
->f_mode
& FMODE_WRITE
))
986 * Make sure there are no mandatory locks on the file.
988 if (locks_verify_locked(inode
))
991 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
992 if (!(file
->f_mode
& FMODE_WRITE
))
993 vm_flags
&= ~(VM_MAYWRITE
| VM_SHARED
);
997 if (!(file
->f_mode
& FMODE_READ
))
999 if (file
->f_path
.mnt
->mnt_flags
& MNT_NOEXEC
) {
1000 if (vm_flags
& VM_EXEC
)
1002 vm_flags
&= ~VM_MAYEXEC
;
1004 if (is_file_hugepages(file
))
1007 if (!file
->f_op
|| !file
->f_op
->mmap
)
1015 switch (flags
& MAP_TYPE
) {
1017 vm_flags
|= VM_SHARED
| VM_MAYSHARE
;
1021 * Set pgoff according to addr for anon_vma.
1023 pgoff
= addr
>> PAGE_SHIFT
;
1030 error
= security_file_mmap(file
, reqprot
, prot
, flags
, addr
, 0);
1034 return mmap_region(file
, addr
, len
, flags
, vm_flags
, pgoff
,
1037 EXPORT_SYMBOL(do_mmap_pgoff
);
1040 * Some shared mappigns will want the pages marked read-only
1041 * to track write events. If so, we'll downgrade vm_page_prot
1042 * to the private version (using protection_map[] without the
1045 int vma_wants_writenotify(struct vm_area_struct
*vma
)
1047 unsigned int vm_flags
= vma
->vm_flags
;
1049 /* If it was private or non-writable, the write bit is already clear */
1050 if ((vm_flags
& (VM_WRITE
|VM_SHARED
)) != ((VM_WRITE
|VM_SHARED
)))
1053 /* The backer wishes to know when pages are first written to? */
1054 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
)
1057 /* The open routine did something to the protections already? */
1058 if (pgprot_val(vma
->vm_page_prot
) !=
1059 pgprot_val(vm_get_page_prot(vm_flags
)))
1062 /* Specialty mapping? */
1063 if (vm_flags
& (VM_PFNMAP
|VM_INSERTPAGE
))
1066 /* Can the mapping track the dirty pages? */
1067 return vma
->vm_file
&& vma
->vm_file
->f_mapping
&&
1068 mapping_cap_account_dirty(vma
->vm_file
->f_mapping
);
1071 unsigned long mmap_region(struct file
*file
, unsigned long addr
,
1072 unsigned long len
, unsigned long flags
,
1073 unsigned int vm_flags
, unsigned long pgoff
,
1076 struct mm_struct
*mm
= current
->mm
;
1077 struct vm_area_struct
*vma
, *prev
;
1078 int correct_wcount
= 0;
1080 struct rb_node
**rb_link
, *rb_parent
;
1081 unsigned long charged
= 0;
1082 struct inode
*inode
= file
? file
->f_path
.dentry
->d_inode
: NULL
;
1084 /* Clear old maps */
1087 vma
= find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
1088 if (vma
&& vma
->vm_start
< addr
+ len
) {
1089 if (do_munmap(mm
, addr
, len
))
1094 /* Check against address space limit. */
1095 if (!may_expand_vm(mm
, len
>> PAGE_SHIFT
))
1098 if (accountable
&& (!(flags
& MAP_NORESERVE
) ||
1099 sysctl_overcommit_memory
== OVERCOMMIT_NEVER
)) {
1100 if (vm_flags
& VM_SHARED
) {
1101 /* Check memory availability in shmem_file_setup? */
1102 vm_flags
|= VM_ACCOUNT
;
1103 } else if (vm_flags
& VM_WRITE
) {
1105 * Private writable mapping: check memory availability
1107 charged
= len
>> PAGE_SHIFT
;
1108 if (security_vm_enough_memory(charged
))
1110 vm_flags
|= VM_ACCOUNT
;
1115 * Can we just expand an old private anonymous mapping?
1116 * The VM_SHARED test is necessary because shmem_zero_setup
1117 * will create the file object for a shared anonymous map below.
1119 if (!file
&& !(vm_flags
& VM_SHARED
) &&
1120 vma_merge(mm
, prev
, addr
, addr
+ len
, vm_flags
,
1121 NULL
, NULL
, pgoff
, NULL
))
1125 * Determine the object being mapped and call the appropriate
1126 * specific mapper. the address has already been validated, but
1127 * not unmapped, but the maps are removed from the list.
1129 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1136 vma
->vm_start
= addr
;
1137 vma
->vm_end
= addr
+ len
;
1138 vma
->vm_flags
= vm_flags
;
1139 vma
->vm_page_prot
= vm_get_page_prot(vm_flags
);
1140 vma
->vm_pgoff
= pgoff
;
1144 if (vm_flags
& (VM_GROWSDOWN
|VM_GROWSUP
))
1146 if (vm_flags
& VM_DENYWRITE
) {
1147 error
= deny_write_access(file
);
1152 vma
->vm_file
= file
;
1154 error
= file
->f_op
->mmap(file
, vma
);
1156 goto unmap_and_free_vma
;
1157 } else if (vm_flags
& VM_SHARED
) {
1158 error
= shmem_zero_setup(vma
);
1163 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1164 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1165 * that memory reservation must be checked; but that reservation
1166 * belongs to shared memory object, not to vma: so now clear it.
1168 if ((vm_flags
& (VM_SHARED
|VM_ACCOUNT
)) == (VM_SHARED
|VM_ACCOUNT
))
1169 vma
->vm_flags
&= ~VM_ACCOUNT
;
1171 /* Can addr have changed??
1173 * Answer: Yes, several device drivers can do it in their
1174 * f_op->mmap method. -DaveM
1176 addr
= vma
->vm_start
;
1177 pgoff
= vma
->vm_pgoff
;
1178 vm_flags
= vma
->vm_flags
;
1180 if (vma_wants_writenotify(vma
))
1181 vma
->vm_page_prot
= vm_get_page_prot(vm_flags
& ~VM_SHARED
);
1183 if (file
&& vma_merge(mm
, prev
, addr
, vma
->vm_end
,
1184 vma
->vm_flags
, NULL
, file
, pgoff
, vma_policy(vma
))) {
1185 mpol_free(vma_policy(vma
));
1186 kmem_cache_free(vm_area_cachep
, vma
);
1189 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
1190 file
= vma
->vm_file
;
1193 /* Once vma denies write, undo our temporary denial count */
1195 atomic_inc(&inode
->i_writecount
);
1197 mm
->total_vm
+= len
>> PAGE_SHIFT
;
1198 vm_stat_account(mm
, vm_flags
, file
, len
>> PAGE_SHIFT
);
1199 if (vm_flags
& VM_LOCKED
) {
1200 mm
->locked_vm
+= len
>> PAGE_SHIFT
;
1201 make_pages_present(addr
, addr
+ len
);
1203 if ((flags
& MAP_POPULATE
) && !(flags
& MAP_NONBLOCK
))
1204 make_pages_present(addr
, addr
+ len
);
1209 atomic_inc(&inode
->i_writecount
);
1210 vma
->vm_file
= NULL
;
1213 /* Undo any partial mapping done by a device driver. */
1214 unmap_region(mm
, vma
, prev
, vma
->vm_start
, vma
->vm_end
);
1217 kmem_cache_free(vm_area_cachep
, vma
);
1220 vm_unacct_memory(charged
);
1224 /* Get an address range which is currently unmapped.
1225 * For shmat() with addr=0.
1227 * Ugly calling convention alert:
1228 * Return value with the low bits set means error value,
1230 * if (ret & ~PAGE_MASK)
1233 * This function "knows" that -ENOMEM has the bits set.
1235 #ifndef HAVE_ARCH_UNMAPPED_AREA
1237 arch_get_unmapped_area(struct file
*filp
, unsigned long addr
,
1238 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
1240 struct mm_struct
*mm
= current
->mm
;
1241 struct vm_area_struct
*vma
;
1242 unsigned long start_addr
;
1244 if (len
> TASK_SIZE
)
1247 if (flags
& MAP_FIXED
)
1251 addr
= PAGE_ALIGN(addr
);
1252 vma
= find_vma(mm
, addr
);
1253 if (TASK_SIZE
- len
>= addr
&&
1254 (!vma
|| addr
+ len
<= vma
->vm_start
))
1257 if (len
> mm
->cached_hole_size
) {
1258 start_addr
= addr
= mm
->free_area_cache
;
1260 start_addr
= addr
= TASK_UNMAPPED_BASE
;
1261 mm
->cached_hole_size
= 0;
1265 for (vma
= find_vma(mm
, addr
); ; vma
= vma
->vm_next
) {
1266 /* At this point: (!vma || addr < vma->vm_end). */
1267 if (TASK_SIZE
- len
< addr
) {
1269 * Start a new search - just in case we missed
1272 if (start_addr
!= TASK_UNMAPPED_BASE
) {
1273 addr
= TASK_UNMAPPED_BASE
;
1275 mm
->cached_hole_size
= 0;
1280 if (!vma
|| addr
+ len
<= vma
->vm_start
) {
1282 * Remember the place where we stopped the search:
1284 mm
->free_area_cache
= addr
+ len
;
1287 if (addr
+ mm
->cached_hole_size
< vma
->vm_start
)
1288 mm
->cached_hole_size
= vma
->vm_start
- addr
;
1294 void arch_unmap_area(struct mm_struct
*mm
, unsigned long addr
)
1297 * Is this a new hole at the lowest possible address?
1299 if (addr
>= TASK_UNMAPPED_BASE
&& addr
< mm
->free_area_cache
) {
1300 mm
->free_area_cache
= addr
;
1301 mm
->cached_hole_size
= ~0UL;
1306 * This mmap-allocator allocates new areas top-down from below the
1307 * stack's low limit (the base):
1309 #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1311 arch_get_unmapped_area_topdown(struct file
*filp
, const unsigned long addr0
,
1312 const unsigned long len
, const unsigned long pgoff
,
1313 const unsigned long flags
)
1315 struct vm_area_struct
*vma
;
1316 struct mm_struct
*mm
= current
->mm
;
1317 unsigned long addr
= addr0
;
1319 /* requested length too big for entire address space */
1320 if (len
> TASK_SIZE
)
1323 if (flags
& MAP_FIXED
)
1326 /* requesting a specific address */
1328 addr
= PAGE_ALIGN(addr
);
1329 vma
= find_vma(mm
, addr
);
1330 if (TASK_SIZE
- len
>= addr
&&
1331 (!vma
|| addr
+ len
<= vma
->vm_start
))
1335 /* check if free_area_cache is useful for us */
1336 if (len
<= mm
->cached_hole_size
) {
1337 mm
->cached_hole_size
= 0;
1338 mm
->free_area_cache
= mm
->mmap_base
;
1341 /* either no address requested or can't fit in requested address hole */
1342 addr
= mm
->free_area_cache
;
1344 /* make sure it can fit in the remaining address space */
1346 vma
= find_vma(mm
, addr
-len
);
1347 if (!vma
|| addr
<= vma
->vm_start
)
1348 /* remember the address as a hint for next time */
1349 return (mm
->free_area_cache
= addr
-len
);
1352 if (mm
->mmap_base
< len
)
1355 addr
= mm
->mmap_base
-len
;
1359 * Lookup failure means no vma is above this address,
1360 * else if new region fits below vma->vm_start,
1361 * return with success:
1363 vma
= find_vma(mm
, addr
);
1364 if (!vma
|| addr
+len
<= vma
->vm_start
)
1365 /* remember the address as a hint for next time */
1366 return (mm
->free_area_cache
= addr
);
1368 /* remember the largest hole we saw so far */
1369 if (addr
+ mm
->cached_hole_size
< vma
->vm_start
)
1370 mm
->cached_hole_size
= vma
->vm_start
- addr
;
1372 /* try just below the current vma->vm_start */
1373 addr
= vma
->vm_start
-len
;
1374 } while (len
< vma
->vm_start
);
1378 * A failed mmap() very likely causes application failure,
1379 * so fall back to the bottom-up function here. This scenario
1380 * can happen with large stack limits and large mmap()
1383 mm
->cached_hole_size
= ~0UL;
1384 mm
->free_area_cache
= TASK_UNMAPPED_BASE
;
1385 addr
= arch_get_unmapped_area(filp
, addr0
, len
, pgoff
, flags
);
1387 * Restore the topdown base:
1389 mm
->free_area_cache
= mm
->mmap_base
;
1390 mm
->cached_hole_size
= ~0UL;
1396 void arch_unmap_area_topdown(struct mm_struct
*mm
, unsigned long addr
)
1399 * Is this a new hole at the highest possible address?
1401 if (addr
> mm
->free_area_cache
)
1402 mm
->free_area_cache
= addr
;
1404 /* dont allow allocations above current base */
1405 if (mm
->free_area_cache
> mm
->mmap_base
)
1406 mm
->free_area_cache
= mm
->mmap_base
;
1410 get_unmapped_area(struct file
*file
, unsigned long addr
, unsigned long len
,
1411 unsigned long pgoff
, unsigned long flags
)
1413 unsigned long (*get_area
)(struct file
*, unsigned long,
1414 unsigned long, unsigned long, unsigned long);
1416 get_area
= current
->mm
->get_unmapped_area
;
1417 if (file
&& file
->f_op
&& file
->f_op
->get_unmapped_area
)
1418 get_area
= file
->f_op
->get_unmapped_area
;
1419 addr
= get_area(file
, addr
, len
, pgoff
, flags
);
1420 if (IS_ERR_VALUE(addr
))
1423 if (addr
> TASK_SIZE
- len
)
1425 if (addr
& ~PAGE_MASK
)
1428 return arch_rebalance_pgtables(addr
, len
);
1431 EXPORT_SYMBOL(get_unmapped_area
);
1433 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1434 struct vm_area_struct
* find_vma(struct mm_struct
* mm
, unsigned long addr
)
1436 struct vm_area_struct
*vma
= NULL
;
1439 /* Check the cache first. */
1440 /* (Cache hit rate is typically around 35%.) */
1441 vma
= mm
->mmap_cache
;
1442 if (!(vma
&& vma
->vm_end
> addr
&& vma
->vm_start
<= addr
)) {
1443 struct rb_node
* rb_node
;
1445 rb_node
= mm
->mm_rb
.rb_node
;
1449 struct vm_area_struct
* vma_tmp
;
1451 vma_tmp
= rb_entry(rb_node
,
1452 struct vm_area_struct
, vm_rb
);
1454 if (vma_tmp
->vm_end
> addr
) {
1456 if (vma_tmp
->vm_start
<= addr
)
1458 rb_node
= rb_node
->rb_left
;
1460 rb_node
= rb_node
->rb_right
;
1463 mm
->mmap_cache
= vma
;
1469 EXPORT_SYMBOL(find_vma
);
1471 /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1472 struct vm_area_struct
*
1473 find_vma_prev(struct mm_struct
*mm
, unsigned long addr
,
1474 struct vm_area_struct
**pprev
)
1476 struct vm_area_struct
*vma
= NULL
, *prev
= NULL
;
1477 struct rb_node
* rb_node
;
1481 /* Guard against addr being lower than the first VMA */
1484 /* Go through the RB tree quickly. */
1485 rb_node
= mm
->mm_rb
.rb_node
;
1488 struct vm_area_struct
*vma_tmp
;
1489 vma_tmp
= rb_entry(rb_node
, struct vm_area_struct
, vm_rb
);
1491 if (addr
< vma_tmp
->vm_end
) {
1492 rb_node
= rb_node
->rb_left
;
1495 if (!prev
->vm_next
|| (addr
< prev
->vm_next
->vm_end
))
1497 rb_node
= rb_node
->rb_right
;
1503 return prev
? prev
->vm_next
: vma
;
1507 * Verify that the stack growth is acceptable and
1508 * update accounting. This is shared with both the
1509 * grow-up and grow-down cases.
1511 static int acct_stack_growth(struct vm_area_struct
* vma
, unsigned long size
, unsigned long grow
)
1513 struct mm_struct
*mm
= vma
->vm_mm
;
1514 struct rlimit
*rlim
= current
->signal
->rlim
;
1515 unsigned long new_start
;
1517 /* address space limit tests */
1518 if (!may_expand_vm(mm
, grow
))
1521 /* Stack limit test */
1522 if (size
> rlim
[RLIMIT_STACK
].rlim_cur
)
1525 /* mlock limit tests */
1526 if (vma
->vm_flags
& VM_LOCKED
) {
1527 unsigned long locked
;
1528 unsigned long limit
;
1529 locked
= mm
->locked_vm
+ grow
;
1530 limit
= rlim
[RLIMIT_MEMLOCK
].rlim_cur
>> PAGE_SHIFT
;
1531 if (locked
> limit
&& !capable(CAP_IPC_LOCK
))
1535 /* Check to ensure the stack will not grow into a hugetlb-only region */
1536 new_start
= (vma
->vm_flags
& VM_GROWSUP
) ? vma
->vm_start
:
1538 if (is_hugepage_only_range(vma
->vm_mm
, new_start
, size
))
1542 * Overcommit.. This must be the final test, as it will
1543 * update security statistics.
1545 if (security_vm_enough_memory(grow
))
1548 /* Ok, everything looks good - let it rip */
1549 mm
->total_vm
+= grow
;
1550 if (vma
->vm_flags
& VM_LOCKED
)
1551 mm
->locked_vm
+= grow
;
1552 vm_stat_account(mm
, vma
->vm_flags
, vma
->vm_file
, grow
);
1556 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1558 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1559 * vma is the last one with address > vma->vm_end. Have to extend vma.
1564 int expand_upwards(struct vm_area_struct
*vma
, unsigned long address
)
1568 if (!(vma
->vm_flags
& VM_GROWSUP
))
1572 * We must make sure the anon_vma is allocated
1573 * so that the anon_vma locking is not a noop.
1575 if (unlikely(anon_vma_prepare(vma
)))
1580 * vma->vm_start/vm_end cannot change under us because the caller
1581 * is required to hold the mmap_sem in read mode. We need the
1582 * anon_vma lock to serialize against concurrent expand_stacks.
1583 * Also guard against wrapping around to address 0.
1585 if (address
< PAGE_ALIGN(address
+4))
1586 address
= PAGE_ALIGN(address
+4);
1588 anon_vma_unlock(vma
);
1593 /* Somebody else might have raced and expanded it already */
1594 if (address
> vma
->vm_end
) {
1595 unsigned long size
, grow
;
1597 size
= address
- vma
->vm_start
;
1598 grow
= (address
- vma
->vm_end
) >> PAGE_SHIFT
;
1600 error
= acct_stack_growth(vma
, size
, grow
);
1602 vma
->vm_end
= address
;
1604 anon_vma_unlock(vma
);
1607 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1610 * vma is the first one with address < vma->vm_start. Have to extend vma.
1612 static inline int expand_downwards(struct vm_area_struct
*vma
,
1613 unsigned long address
)
1618 * We must make sure the anon_vma is allocated
1619 * so that the anon_vma locking is not a noop.
1621 if (unlikely(anon_vma_prepare(vma
)))
1624 address
&= PAGE_MASK
;
1625 error
= security_file_mmap(NULL
, 0, 0, 0, address
, 1);
1632 * vma->vm_start/vm_end cannot change under us because the caller
1633 * is required to hold the mmap_sem in read mode. We need the
1634 * anon_vma lock to serialize against concurrent expand_stacks.
1637 /* Somebody else might have raced and expanded it already */
1638 if (address
< vma
->vm_start
) {
1639 unsigned long size
, grow
;
1641 size
= vma
->vm_end
- address
;
1642 grow
= (vma
->vm_start
- address
) >> PAGE_SHIFT
;
1644 error
= acct_stack_growth(vma
, size
, grow
);
1646 vma
->vm_start
= address
;
1647 vma
->vm_pgoff
-= grow
;
1650 anon_vma_unlock(vma
);
1654 int expand_stack_downwards(struct vm_area_struct
*vma
, unsigned long address
)
1656 return expand_downwards(vma
, address
);
1659 #ifdef CONFIG_STACK_GROWSUP
1660 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
1662 return expand_upwards(vma
, address
);
1665 struct vm_area_struct
*
1666 find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
1668 struct vm_area_struct
*vma
, *prev
;
1671 vma
= find_vma_prev(mm
, addr
, &prev
);
1672 if (vma
&& (vma
->vm_start
<= addr
))
1674 if (!prev
|| expand_stack(prev
, addr
))
1676 if (prev
->vm_flags
& VM_LOCKED
)
1677 make_pages_present(addr
, prev
->vm_end
);
1681 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
1683 return expand_downwards(vma
, address
);
1686 struct vm_area_struct
*
1687 find_extend_vma(struct mm_struct
* mm
, unsigned long addr
)
1689 struct vm_area_struct
* vma
;
1690 unsigned long start
;
1693 vma
= find_vma(mm
,addr
);
1696 if (vma
->vm_start
<= addr
)
1698 if (!(vma
->vm_flags
& VM_GROWSDOWN
))
1700 start
= vma
->vm_start
;
1701 if (expand_stack(vma
, addr
))
1703 if (vma
->vm_flags
& VM_LOCKED
)
1704 make_pages_present(addr
, start
);
1710 * Ok - we have the memory areas we should free on the vma list,
1711 * so release them, and do the vma updates.
1713 * Called with the mm semaphore held.
1715 static void remove_vma_list(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
1717 /* Update high watermark before we lower total_vm */
1718 update_hiwater_vm(mm
);
1720 long nrpages
= vma_pages(vma
);
1722 mm
->total_vm
-= nrpages
;
1723 if (vma
->vm_flags
& VM_LOCKED
)
1724 mm
->locked_vm
-= nrpages
;
1725 vm_stat_account(mm
, vma
->vm_flags
, vma
->vm_file
, -nrpages
);
1726 vma
= remove_vma(vma
);
1732 * Get rid of page table information in the indicated region.
1734 * Called with the mm semaphore held.
1736 static void unmap_region(struct mm_struct
*mm
,
1737 struct vm_area_struct
*vma
, struct vm_area_struct
*prev
,
1738 unsigned long start
, unsigned long end
)
1740 struct vm_area_struct
*next
= prev
? prev
->vm_next
: mm
->mmap
;
1741 struct mmu_gather
*tlb
;
1742 unsigned long nr_accounted
= 0;
1745 tlb
= tlb_gather_mmu(mm
, 0);
1746 update_hiwater_rss(mm
);
1747 unmap_vmas(&tlb
, vma
, start
, end
, &nr_accounted
, NULL
);
1748 vm_unacct_memory(nr_accounted
);
1749 free_pgtables(&tlb
, vma
, prev
? prev
->vm_end
: FIRST_USER_ADDRESS
,
1750 next
? next
->vm_start
: 0);
1751 tlb_finish_mmu(tlb
, start
, end
);
1755 * Create a list of vma's touched by the unmap, removing them from the mm's
1756 * vma list as we go..
1759 detach_vmas_to_be_unmapped(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1760 struct vm_area_struct
*prev
, unsigned long end
)
1762 struct vm_area_struct
**insertion_point
;
1763 struct vm_area_struct
*tail_vma
= NULL
;
1766 insertion_point
= (prev
? &prev
->vm_next
: &mm
->mmap
);
1768 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
1772 } while (vma
&& vma
->vm_start
< end
);
1773 *insertion_point
= vma
;
1774 tail_vma
->vm_next
= NULL
;
1775 if (mm
->unmap_area
== arch_unmap_area
)
1776 addr
= prev
? prev
->vm_end
: mm
->mmap_base
;
1778 addr
= vma
? vma
->vm_start
: mm
->mmap_base
;
1779 mm
->unmap_area(mm
, addr
);
1780 mm
->mmap_cache
= NULL
; /* Kill the cache. */
1784 * Split a vma into two pieces at address 'addr', a new vma is allocated
1785 * either for the first part or the tail.
1787 int split_vma(struct mm_struct
* mm
, struct vm_area_struct
* vma
,
1788 unsigned long addr
, int new_below
)
1790 struct mempolicy
*pol
;
1791 struct vm_area_struct
*new;
1793 if (is_vm_hugetlb_page(vma
) && (addr
& ~HPAGE_MASK
))
1796 if (mm
->map_count
>= sysctl_max_map_count
)
1799 new = kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
1803 /* most fields are the same, copy all, and then fixup */
1809 new->vm_start
= addr
;
1810 new->vm_pgoff
+= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
);
1813 pol
= mpol_copy(vma_policy(vma
));
1815 kmem_cache_free(vm_area_cachep
, new);
1816 return PTR_ERR(pol
);
1818 vma_set_policy(new, pol
);
1821 get_file(new->vm_file
);
1823 if (new->vm_ops
&& new->vm_ops
->open
)
1824 new->vm_ops
->open(new);
1827 vma_adjust(vma
, addr
, vma
->vm_end
, vma
->vm_pgoff
+
1828 ((addr
- new->vm_start
) >> PAGE_SHIFT
), new);
1830 vma_adjust(vma
, vma
->vm_start
, addr
, vma
->vm_pgoff
, new);
1835 /* Munmap is split into 2 main parts -- this part which finds
1836 * what needs doing, and the areas themselves, which do the
1837 * work. This now handles partial unmappings.
1838 * Jeremy Fitzhardinge <jeremy@goop.org>
1840 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
)
1843 struct vm_area_struct
*vma
, *prev
, *last
;
1845 if ((start
& ~PAGE_MASK
) || start
> TASK_SIZE
|| len
> TASK_SIZE
-start
)
1848 if ((len
= PAGE_ALIGN(len
)) == 0)
1851 /* Find the first overlapping VMA */
1852 vma
= find_vma_prev(mm
, start
, &prev
);
1855 /* we have start < vma->vm_end */
1857 /* if it doesn't overlap, we have nothing.. */
1859 if (vma
->vm_start
>= end
)
1863 * If we need to split any vma, do it now to save pain later.
1865 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1866 * unmapped vm_area_struct will remain in use: so lower split_vma
1867 * places tmp vma above, and higher split_vma places tmp vma below.
1869 if (start
> vma
->vm_start
) {
1870 int error
= split_vma(mm
, vma
, start
, 0);
1876 /* Does it split the last one? */
1877 last
= find_vma(mm
, end
);
1878 if (last
&& end
> last
->vm_start
) {
1879 int error
= split_vma(mm
, last
, end
, 1);
1883 vma
= prev
? prev
->vm_next
: mm
->mmap
;
1886 * Remove the vma's, and unmap the actual pages
1888 detach_vmas_to_be_unmapped(mm
, vma
, prev
, end
);
1889 unmap_region(mm
, vma
, prev
, start
, end
);
1891 /* Fix up all other VM information */
1892 remove_vma_list(mm
, vma
);
1897 EXPORT_SYMBOL(do_munmap
);
1899 asmlinkage
long sys_munmap(unsigned long addr
, size_t len
)
1902 struct mm_struct
*mm
= current
->mm
;
1904 profile_munmap(addr
);
1906 down_write(&mm
->mmap_sem
);
1907 ret
= do_munmap(mm
, addr
, len
);
1908 up_write(&mm
->mmap_sem
);
1912 static inline void verify_mm_writelocked(struct mm_struct
*mm
)
1914 #ifdef CONFIG_DEBUG_VM
1915 if (unlikely(down_read_trylock(&mm
->mmap_sem
))) {
1917 up_read(&mm
->mmap_sem
);
1923 * this is really a simplified "do_mmap". it only handles
1924 * anonymous maps. eventually we may be able to do some
1925 * brk-specific accounting here.
1927 unsigned long do_brk(unsigned long addr
, unsigned long len
)
1929 struct mm_struct
* mm
= current
->mm
;
1930 struct vm_area_struct
* vma
, * prev
;
1931 unsigned long flags
;
1932 struct rb_node
** rb_link
, * rb_parent
;
1933 pgoff_t pgoff
= addr
>> PAGE_SHIFT
;
1936 len
= PAGE_ALIGN(len
);
1940 if ((addr
+ len
) > TASK_SIZE
|| (addr
+ len
) < addr
)
1943 if (is_hugepage_only_range(mm
, addr
, len
))
1946 error
= security_file_mmap(NULL
, 0, 0, 0, addr
, 1);
1950 flags
= VM_DATA_DEFAULT_FLAGS
| VM_ACCOUNT
| mm
->def_flags
;
1952 error
= arch_mmap_check(addr
, len
, flags
);
1959 if (mm
->def_flags
& VM_LOCKED
) {
1960 unsigned long locked
, lock_limit
;
1961 locked
= len
>> PAGE_SHIFT
;
1962 locked
+= mm
->locked_vm
;
1963 lock_limit
= current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
;
1964 lock_limit
>>= PAGE_SHIFT
;
1965 if (locked
> lock_limit
&& !capable(CAP_IPC_LOCK
))
1970 * mm->mmap_sem is required to protect against another thread
1971 * changing the mappings in case we sleep.
1973 verify_mm_writelocked(mm
);
1976 * Clear old maps. this also does some error checking for us
1979 vma
= find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
1980 if (vma
&& vma
->vm_start
< addr
+ len
) {
1981 if (do_munmap(mm
, addr
, len
))
1986 /* Check against address space limits *after* clearing old maps... */
1987 if (!may_expand_vm(mm
, len
>> PAGE_SHIFT
))
1990 if (mm
->map_count
> sysctl_max_map_count
)
1993 if (security_vm_enough_memory(len
>> PAGE_SHIFT
))
1996 /* Can we just expand an old private anonymous mapping? */
1997 if (vma_merge(mm
, prev
, addr
, addr
+ len
, flags
,
1998 NULL
, NULL
, pgoff
, NULL
))
2002 * create a vma struct for an anonymous mapping
2004 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
2006 vm_unacct_memory(len
>> PAGE_SHIFT
);
2011 vma
->vm_start
= addr
;
2012 vma
->vm_end
= addr
+ len
;
2013 vma
->vm_pgoff
= pgoff
;
2014 vma
->vm_flags
= flags
;
2015 vma
->vm_page_prot
= vm_get_page_prot(flags
);
2016 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
2018 mm
->total_vm
+= len
>> PAGE_SHIFT
;
2019 if (flags
& VM_LOCKED
) {
2020 mm
->locked_vm
+= len
>> PAGE_SHIFT
;
2021 make_pages_present(addr
, addr
+ len
);
2026 EXPORT_SYMBOL(do_brk
);
2028 /* Release all mmaps. */
2029 void exit_mmap(struct mm_struct
*mm
)
2031 struct mmu_gather
*tlb
;
2032 struct vm_area_struct
*vma
= mm
->mmap
;
2033 unsigned long nr_accounted
= 0;
2036 /* mm's last user has gone, and its about to be pulled down */
2041 tlb
= tlb_gather_mmu(mm
, 1);
2042 /* Don't update_hiwater_rss(mm) here, do_exit already did */
2043 /* Use -1 here to ensure all VMAs in the mm are unmapped */
2044 end
= unmap_vmas(&tlb
, vma
, 0, -1, &nr_accounted
, NULL
);
2045 vm_unacct_memory(nr_accounted
);
2046 free_pgtables(&tlb
, vma
, FIRST_USER_ADDRESS
, 0);
2047 tlb_finish_mmu(tlb
, 0, end
);
2050 * Walk the list again, actually closing and freeing it,
2051 * with preemption enabled, without holding any MM locks.
2054 vma
= remove_vma(vma
);
2056 BUG_ON(mm
->nr_ptes
> (FIRST_USER_ADDRESS
+PMD_SIZE
-1)>>PMD_SHIFT
);
2059 /* Insert vm structure into process list sorted by address
2060 * and into the inode's i_mmap tree. If vm_file is non-NULL
2061 * then i_mmap_lock is taken here.
2063 int insert_vm_struct(struct mm_struct
* mm
, struct vm_area_struct
* vma
)
2065 struct vm_area_struct
* __vma
, * prev
;
2066 struct rb_node
** rb_link
, * rb_parent
;
2069 * The vm_pgoff of a purely anonymous vma should be irrelevant
2070 * until its first write fault, when page's anon_vma and index
2071 * are set. But now set the vm_pgoff it will almost certainly
2072 * end up with (unless mremap moves it elsewhere before that
2073 * first wfault), so /proc/pid/maps tells a consistent story.
2075 * By setting it to reflect the virtual start address of the
2076 * vma, merges and splits can happen in a seamless way, just
2077 * using the existing file pgoff checks and manipulations.
2078 * Similarly in do_mmap_pgoff and in do_brk.
2080 if (!vma
->vm_file
) {
2081 BUG_ON(vma
->anon_vma
);
2082 vma
->vm_pgoff
= vma
->vm_start
>> PAGE_SHIFT
;
2084 __vma
= find_vma_prepare(mm
,vma
->vm_start
,&prev
,&rb_link
,&rb_parent
);
2085 if (__vma
&& __vma
->vm_start
< vma
->vm_end
)
2087 if ((vma
->vm_flags
& VM_ACCOUNT
) &&
2088 security_vm_enough_memory_mm(mm
, vma_pages(vma
)))
2090 vma_link(mm
, vma
, prev
, rb_link
, rb_parent
);
2095 * Copy the vma structure to a new location in the same mm,
2096 * prior to moving page table entries, to effect an mremap move.
2098 struct vm_area_struct
*copy_vma(struct vm_area_struct
**vmap
,
2099 unsigned long addr
, unsigned long len
, pgoff_t pgoff
)
2101 struct vm_area_struct
*vma
= *vmap
;
2102 unsigned long vma_start
= vma
->vm_start
;
2103 struct mm_struct
*mm
= vma
->vm_mm
;
2104 struct vm_area_struct
*new_vma
, *prev
;
2105 struct rb_node
**rb_link
, *rb_parent
;
2106 struct mempolicy
*pol
;
2109 * If anonymous vma has not yet been faulted, update new pgoff
2110 * to match new location, to increase its chance of merging.
2112 if (!vma
->vm_file
&& !vma
->anon_vma
)
2113 pgoff
= addr
>> PAGE_SHIFT
;
2115 find_vma_prepare(mm
, addr
, &prev
, &rb_link
, &rb_parent
);
2116 new_vma
= vma_merge(mm
, prev
, addr
, addr
+ len
, vma
->vm_flags
,
2117 vma
->anon_vma
, vma
->vm_file
, pgoff
, vma_policy(vma
));
2120 * Source vma may have been merged into new_vma
2122 if (vma_start
>= new_vma
->vm_start
&&
2123 vma_start
< new_vma
->vm_end
)
2126 new_vma
= kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
2129 pol
= mpol_copy(vma_policy(vma
));
2131 kmem_cache_free(vm_area_cachep
, new_vma
);
2134 vma_set_policy(new_vma
, pol
);
2135 new_vma
->vm_start
= addr
;
2136 new_vma
->vm_end
= addr
+ len
;
2137 new_vma
->vm_pgoff
= pgoff
;
2138 if (new_vma
->vm_file
)
2139 get_file(new_vma
->vm_file
);
2140 if (new_vma
->vm_ops
&& new_vma
->vm_ops
->open
)
2141 new_vma
->vm_ops
->open(new_vma
);
2142 vma_link(mm
, new_vma
, prev
, rb_link
, rb_parent
);
2149 * Return true if the calling process may expand its vm space by the passed
2152 int may_expand_vm(struct mm_struct
*mm
, unsigned long npages
)
2154 unsigned long cur
= mm
->total_vm
; /* pages */
2157 lim
= current
->signal
->rlim
[RLIMIT_AS
].rlim_cur
>> PAGE_SHIFT
;
2159 if (cur
+ npages
> lim
)
2165 static int special_mapping_fault(struct vm_area_struct
*vma
,
2166 struct vm_fault
*vmf
)
2169 struct page
**pages
;
2172 * special mappings have no vm_file, and in that case, the mm
2173 * uses vm_pgoff internally. So we have to subtract it from here.
2174 * We are allowed to do this because we are the mm; do not copy
2175 * this code into drivers!
2177 pgoff
= vmf
->pgoff
- vma
->vm_pgoff
;
2179 for (pages
= vma
->vm_private_data
; pgoff
&& *pages
; ++pages
)
2183 struct page
*page
= *pages
;
2189 return VM_FAULT_SIGBUS
;
2193 * Having a close hook prevents vma merging regardless of flags.
2195 static void special_mapping_close(struct vm_area_struct
*vma
)
2199 static struct vm_operations_struct special_mapping_vmops
= {
2200 .close
= special_mapping_close
,
2201 .fault
= special_mapping_fault
,
2205 * Called with mm->mmap_sem held for writing.
2206 * Insert a new vma covering the given region, with the given flags.
2207 * Its pages are supplied by the given array of struct page *.
2208 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2209 * The region past the last page supplied will always produce SIGBUS.
2210 * The array pointer and the pages it points to are assumed to stay alive
2211 * for as long as this mapping might exist.
2213 int install_special_mapping(struct mm_struct
*mm
,
2214 unsigned long addr
, unsigned long len
,
2215 unsigned long vm_flags
, struct page
**pages
)
2217 struct vm_area_struct
*vma
;
2219 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
2220 if (unlikely(vma
== NULL
))
2224 vma
->vm_start
= addr
;
2225 vma
->vm_end
= addr
+ len
;
2227 vma
->vm_flags
= vm_flags
| mm
->def_flags
| VM_DONTEXPAND
;
2228 vma
->vm_page_prot
= vm_get_page_prot(vma
->vm_flags
);
2230 vma
->vm_ops
= &special_mapping_vmops
;
2231 vma
->vm_private_data
= pages
;
2233 if (unlikely(insert_vm_struct(mm
, vma
))) {
2234 kmem_cache_free(vm_area_cachep
, vma
);
2238 mm
->total_vm
+= len
>> PAGE_SHIFT
;