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 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
64 int sysctl_overcommit_ratio = 50; /* default is 50% */
65 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
66 atomic_t vm_committed_space = ATOMIC_INIT(0);
69 * Check that a process has enough memory to allocate a new virtual
70 * mapping. 0 means there is enough memory for the allocation to
71 * succeed and -ENOMEM implies there is not.
73 * We currently support three overcommit policies, which are set via the
74 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
76 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
77 * Additional code 2002 Jul 20 by Robert Love.
79 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
81 * Note this is a helper function intended to be used by LSMs which
82 * wish to use this logic.
84 int __vm_enough_memory(long pages, int cap_sys_admin)
86 unsigned long free, allowed;
88 vm_acct_memory(pages);
91 * Sometimes we want to use more memory than we have
93 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
96 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
99 free = get_page_cache_size();
100 free += nr_swap_pages;
103 * Any slabs which are created with the
104 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
105 * which are reclaimable, under pressure. The dentry
106 * cache and most inode caches should fall into this
108 free += atomic_read(&slab_reclaim_pages);
111 * Leave the last 3% for root
120 * nr_free_pages() is very expensive on large systems,
121 * only call if we're about to fail.
130 vm_unacct_memory(pages);
134 allowed = (totalram_pages - hugetlb_total_pages())
135 * sysctl_overcommit_ratio / 100;
137 * Leave the last 3% for root
140 allowed -= allowed / 32;
141 allowed += total_swap_pages;
143 /* Don't let a single process grow too big:
144 leave 3% of the size of this process for other processes */
145 allowed -= current->mm->total_vm / 32;
148 * cast `allowed' as a signed long because vm_committed_space
149 * sometimes has a negative value
151 if (atomic_read(&vm_committed_space) < (long)allowed)
154 vm_unacct_memory(pages);
159 EXPORT_SYMBOL(__vm_enough_memory);
162 * Requires inode->i_mapping->i_mmap_lock
164 static void __remove_shared_vm_struct(struct vm_area_struct *vma,
165 struct file *file, struct address_space *mapping)
167 if (vma->vm_flags & VM_DENYWRITE)
168 atomic_inc(&file->f_dentry->d_inode->i_writecount);
169 if (vma->vm_flags & VM_SHARED)
170 mapping->i_mmap_writable--;
172 flush_dcache_mmap_lock(mapping);
173 if (unlikely(vma->vm_flags & VM_NONLINEAR))
174 list_del_init(&vma->shared.vm_set.list);
176 vma_prio_tree_remove(vma, &mapping->i_mmap);
177 flush_dcache_mmap_unlock(mapping);
181 * Unlink a file-based vm structure from its prio_tree, to hide
182 * vma from rmap and vmtruncate before freeing its page tables.
184 void unlink_file_vma(struct vm_area_struct *vma)
186 struct file *file = vma->vm_file;
189 struct address_space *mapping = file->f_mapping;
190 spin_lock(&mapping->i_mmap_lock);
191 __remove_shared_vm_struct(vma, file, mapping);
192 spin_unlock(&mapping->i_mmap_lock);
197 * Close a vm structure and free it, returning the next.
199 static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
201 struct vm_area_struct *next = vma->vm_next;
204 if (vma->vm_ops && vma->vm_ops->close)
205 vma->vm_ops->close(vma);
208 mpol_free(vma_policy(vma));
209 kmem_cache_free(vm_area_cachep, vma);
213 asmlinkage unsigned long sys_brk(unsigned long brk)
215 unsigned long rlim, retval;
216 unsigned long newbrk, oldbrk;
217 struct mm_struct *mm = current->mm;
219 down_write(&mm->mmap_sem);
221 if (brk < mm->end_code)
225 * Check against rlimit here. If this check is done later after the test
226 * of oldbrk with newbrk then it can escape the test and let the data
227 * segment grow beyond its set limit the in case where the limit is
228 * not page aligned -Ram Gupta
230 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
231 if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
234 newbrk = PAGE_ALIGN(brk);
235 oldbrk = PAGE_ALIGN(mm->brk);
236 if (oldbrk == newbrk)
239 /* Always allow shrinking brk. */
240 if (brk <= mm->brk) {
241 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
246 /* Check against existing mmap mappings. */
247 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
250 /* Ok, looks good - let it rip. */
251 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
257 up_write(&mm->mmap_sem);
262 static int browse_rb(struct rb_root *root)
265 struct rb_node *nd, *pn = NULL;
266 unsigned long prev = 0, pend = 0;
268 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
269 struct vm_area_struct *vma;
270 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
271 if (vma->vm_start < prev)
272 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
273 if (vma->vm_start < pend)
274 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
275 if (vma->vm_start > vma->vm_end)
276 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
281 for (nd = pn; nd; nd = rb_prev(nd)) {
285 printk("backwards %d, forwards %d\n", j, i), i = 0;
289 void validate_mm(struct mm_struct *mm)
293 struct vm_area_struct *tmp = mm->mmap;
298 if (i != mm->map_count)
299 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
300 i = browse_rb(&mm->mm_rb);
301 if (i != mm->map_count)
302 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
306 #define validate_mm(mm) do { } while (0)
309 static struct vm_area_struct *
310 find_vma_prepare(struct mm_struct *mm, unsigned long addr,
311 struct vm_area_struct **pprev, struct rb_node ***rb_link,
312 struct rb_node ** rb_parent)
314 struct vm_area_struct * vma;
315 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
317 __rb_link = &mm->mm_rb.rb_node;
318 rb_prev = __rb_parent = NULL;
322 struct vm_area_struct *vma_tmp;
324 __rb_parent = *__rb_link;
325 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
327 if (vma_tmp->vm_end > addr) {
329 if (vma_tmp->vm_start <= addr)
331 __rb_link = &__rb_parent->rb_left;
333 rb_prev = __rb_parent;
334 __rb_link = &__rb_parent->rb_right;
340 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
341 *rb_link = __rb_link;
342 *rb_parent = __rb_parent;
347 __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
348 struct vm_area_struct *prev, struct rb_node *rb_parent)
351 vma->vm_next = prev->vm_next;
356 vma->vm_next = rb_entry(rb_parent,
357 struct vm_area_struct, vm_rb);
363 void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
364 struct rb_node **rb_link, struct rb_node *rb_parent)
366 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
367 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
370 static inline void __vma_link_file(struct vm_area_struct *vma)
376 struct address_space *mapping = file->f_mapping;
378 if (vma->vm_flags & VM_DENYWRITE)
379 atomic_dec(&file->f_dentry->d_inode->i_writecount);
380 if (vma->vm_flags & VM_SHARED)
381 mapping->i_mmap_writable++;
383 flush_dcache_mmap_lock(mapping);
384 if (unlikely(vma->vm_flags & VM_NONLINEAR))
385 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
387 vma_prio_tree_insert(vma, &mapping->i_mmap);
388 flush_dcache_mmap_unlock(mapping);
393 __vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
394 struct vm_area_struct *prev, struct rb_node **rb_link,
395 struct rb_node *rb_parent)
397 __vma_link_list(mm, vma, prev, rb_parent);
398 __vma_link_rb(mm, vma, rb_link, rb_parent);
399 __anon_vma_link(vma);
402 static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
403 struct vm_area_struct *prev, struct rb_node **rb_link,
404 struct rb_node *rb_parent)
406 struct address_space *mapping = NULL;
409 mapping = vma->vm_file->f_mapping;
412 spin_lock(&mapping->i_mmap_lock);
413 vma->vm_truncate_count = mapping->truncate_count;
417 __vma_link(mm, vma, prev, rb_link, rb_parent);
418 __vma_link_file(vma);
420 anon_vma_unlock(vma);
422 spin_unlock(&mapping->i_mmap_lock);
429 * Helper for vma_adjust in the split_vma insert case:
430 * insert vm structure into list and rbtree and anon_vma,
431 * but it has already been inserted into prio_tree earlier.
434 __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
436 struct vm_area_struct * __vma, * prev;
437 struct rb_node ** rb_link, * rb_parent;
439 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
440 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
441 __vma_link(mm, vma, prev, rb_link, rb_parent);
446 __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
447 struct vm_area_struct *prev)
449 prev->vm_next = vma->vm_next;
450 rb_erase(&vma->vm_rb, &mm->mm_rb);
451 if (mm->mmap_cache == vma)
452 mm->mmap_cache = prev;
456 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
457 * is already present in an i_mmap tree without adjusting the tree.
458 * The following helper function should be used when such adjustments
459 * are necessary. The "insert" vma (if any) is to be inserted
460 * before we drop the necessary locks.
462 void vma_adjust(struct vm_area_struct *vma, unsigned long start,
463 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
465 struct mm_struct *mm = vma->vm_mm;
466 struct vm_area_struct *next = vma->vm_next;
467 struct vm_area_struct *importer = NULL;
468 struct address_space *mapping = NULL;
469 struct prio_tree_root *root = NULL;
470 struct file *file = vma->vm_file;
471 struct anon_vma *anon_vma = NULL;
472 long adjust_next = 0;
475 if (next && !insert) {
476 if (end >= next->vm_end) {
478 * vma expands, overlapping all the next, and
479 * perhaps the one after too (mprotect case 6).
481 again: remove_next = 1 + (end > next->vm_end);
483 anon_vma = next->anon_vma;
485 } else if (end > next->vm_start) {
487 * vma expands, overlapping part of the next:
488 * mprotect case 5 shifting the boundary up.
490 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
491 anon_vma = next->anon_vma;
493 } else if (end < vma->vm_end) {
495 * vma shrinks, and !insert tells it's not
496 * split_vma inserting another: so it must be
497 * mprotect case 4 shifting the boundary down.
499 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
500 anon_vma = next->anon_vma;
506 mapping = file->f_mapping;
507 if (!(vma->vm_flags & VM_NONLINEAR))
508 root = &mapping->i_mmap;
509 spin_lock(&mapping->i_mmap_lock);
511 vma->vm_truncate_count != next->vm_truncate_count) {
513 * unmap_mapping_range might be in progress:
514 * ensure that the expanding vma is rescanned.
516 importer->vm_truncate_count = 0;
519 insert->vm_truncate_count = vma->vm_truncate_count;
521 * Put into prio_tree now, so instantiated pages
522 * are visible to arm/parisc __flush_dcache_page
523 * throughout; but we cannot insert into address
524 * space until vma start or end is updated.
526 __vma_link_file(insert);
531 * When changing only vma->vm_end, we don't really need
532 * anon_vma lock: but is that case worth optimizing out?
535 anon_vma = vma->anon_vma;
537 spin_lock(&anon_vma->lock);
539 * Easily overlooked: when mprotect shifts the boundary,
540 * make sure the expanding vma has anon_vma set if the
541 * shrinking vma had, to cover any anon pages imported.
543 if (importer && !importer->anon_vma) {
544 importer->anon_vma = anon_vma;
545 __anon_vma_link(importer);
550 flush_dcache_mmap_lock(mapping);
551 vma_prio_tree_remove(vma, root);
553 vma_prio_tree_remove(next, root);
556 vma->vm_start = start;
558 vma->vm_pgoff = pgoff;
560 next->vm_start += adjust_next << PAGE_SHIFT;
561 next->vm_pgoff += adjust_next;
566 vma_prio_tree_insert(next, root);
567 vma_prio_tree_insert(vma, root);
568 flush_dcache_mmap_unlock(mapping);
573 * vma_merge has merged next into vma, and needs
574 * us to remove next before dropping the locks.
576 __vma_unlink(mm, next, vma);
578 __remove_shared_vm_struct(next, file, mapping);
580 __anon_vma_merge(vma, next);
583 * split_vma has split insert from vma, and needs
584 * us to insert it before dropping the locks
585 * (it may either follow vma or precede it).
587 __insert_vm_struct(mm, insert);
591 spin_unlock(&anon_vma->lock);
593 spin_unlock(&mapping->i_mmap_lock);
599 mpol_free(vma_policy(next));
600 kmem_cache_free(vm_area_cachep, next);
602 * In mprotect's case 6 (see comments on vma_merge),
603 * we must remove another next too. It would clutter
604 * up the code too much to do both in one go.
606 if (remove_next == 2) {
616 * If the vma has a ->close operation then the driver probably needs to release
617 * per-vma resources, so we don't attempt to merge those.
619 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
621 static inline int is_mergeable_vma(struct vm_area_struct *vma,
622 struct file *file, unsigned long vm_flags)
624 if (vma->vm_flags != vm_flags)
626 if (vma->vm_file != file)
628 if (vma->vm_ops && vma->vm_ops->close)
633 static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
634 struct anon_vma *anon_vma2)
636 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
640 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
641 * in front of (at a lower virtual address and file offset than) the vma.
643 * We cannot merge two vmas if they have differently assigned (non-NULL)
644 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
646 * We don't check here for the merged mmap wrapping around the end of pagecache
647 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
648 * wrap, nor mmaps which cover the final page at index -1UL.
651 can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
652 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
654 if (is_mergeable_vma(vma, file, vm_flags) &&
655 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
656 if (vma->vm_pgoff == vm_pgoff)
663 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
664 * beyond (at a higher virtual address and file offset than) the vma.
666 * We cannot merge two vmas if they have differently assigned (non-NULL)
667 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
670 can_vma_merge_after(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)) {
676 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
677 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
684 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
685 * whether that can be merged with its predecessor or its successor.
686 * Or both (it neatly fills a hole).
688 * In most cases - when called for mmap, brk or mremap - [addr,end) is
689 * certain not to be mapped by the time vma_merge is called; but when
690 * called for mprotect, it is certain to be already mapped (either at
691 * an offset within prev, or at the start of next), and the flags of
692 * this area are about to be changed to vm_flags - and the no-change
693 * case has already been eliminated.
695 * The following mprotect cases have to be considered, where AAAA is
696 * the area passed down from mprotect_fixup, never extending beyond one
697 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
699 * AAAA AAAA AAAA AAAA
700 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
701 * cannot merge might become might become might become
702 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
703 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
704 * mremap move: PPPPNNNNNNNN 8
706 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
707 * might become case 1 below case 2 below case 3 below
709 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
710 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
712 struct vm_area_struct *vma_merge(struct mm_struct *mm,
713 struct vm_area_struct *prev, unsigned long addr,
714 unsigned long end, unsigned long vm_flags,
715 struct anon_vma *anon_vma, struct file *file,
716 pgoff_t pgoff, struct mempolicy *policy)
718 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
719 struct vm_area_struct *area, *next;
722 * We later require that vma->vm_flags == vm_flags,
723 * so this tests vma->vm_flags & VM_SPECIAL, too.
725 if (vm_flags & VM_SPECIAL)
729 next = prev->vm_next;
733 if (next && next->vm_end == end) /* cases 6, 7, 8 */
734 next = next->vm_next;
737 * Can it merge with the predecessor?
739 if (prev && prev->vm_end == addr &&
740 mpol_equal(vma_policy(prev), policy) &&
741 can_vma_merge_after(prev, vm_flags,
742 anon_vma, file, pgoff)) {
744 * OK, it can. Can we now merge in the successor as well?
746 if (next && end == next->vm_start &&
747 mpol_equal(policy, vma_policy(next)) &&
748 can_vma_merge_before(next, vm_flags,
749 anon_vma, file, pgoff+pglen) &&
750 is_mergeable_anon_vma(prev->anon_vma,
753 vma_adjust(prev, prev->vm_start,
754 next->vm_end, prev->vm_pgoff, NULL);
755 } else /* cases 2, 5, 7 */
756 vma_adjust(prev, prev->vm_start,
757 end, prev->vm_pgoff, NULL);
762 * Can this new request be merged in front of next?
764 if (next && end == next->vm_start &&
765 mpol_equal(policy, vma_policy(next)) &&
766 can_vma_merge_before(next, vm_flags,
767 anon_vma, file, pgoff+pglen)) {
768 if (prev && addr < prev->vm_end) /* case 4 */
769 vma_adjust(prev, prev->vm_start,
770 addr, prev->vm_pgoff, NULL);
771 else /* cases 3, 8 */
772 vma_adjust(area, addr, next->vm_end,
773 next->vm_pgoff - pglen, NULL);
781 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
782 * neighbouring vmas for a suitable anon_vma, before it goes off
783 * to allocate a new anon_vma. It checks because a repetitive
784 * sequence of mprotects and faults may otherwise lead to distinct
785 * anon_vmas being allocated, preventing vma merge in subsequent
788 struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
790 struct vm_area_struct *near;
791 unsigned long vm_flags;
798 * Since only mprotect tries to remerge vmas, match flags
799 * which might be mprotected into each other later on.
800 * Neither mlock nor madvise tries to remerge at present,
801 * so leave their flags as obstructing a merge.
803 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
804 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
806 if (near->anon_vma && vma->vm_end == near->vm_start &&
807 mpol_equal(vma_policy(vma), vma_policy(near)) &&
808 can_vma_merge_before(near, vm_flags,
809 NULL, vma->vm_file, vma->vm_pgoff +
810 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
811 return near->anon_vma;
814 * It is potentially slow to have to call find_vma_prev here.
815 * But it's only on the first write fault on the vma, not
816 * every time, and we could devise a way to avoid it later
817 * (e.g. stash info in next's anon_vma_node when assigning
818 * an anon_vma, or when trying vma_merge). Another time.
820 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
824 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
825 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
827 if (near->anon_vma && near->vm_end == vma->vm_start &&
828 mpol_equal(vma_policy(near), vma_policy(vma)) &&
829 can_vma_merge_after(near, vm_flags,
830 NULL, vma->vm_file, vma->vm_pgoff))
831 return near->anon_vma;
834 * There's no absolute need to look only at touching neighbours:
835 * we could search further afield for "compatible" anon_vmas.
836 * But it would probably just be a waste of time searching,
837 * or lead to too many vmas hanging off the same anon_vma.
838 * We're trying to allow mprotect remerging later on,
839 * not trying to minimize memory used for anon_vmas.
844 #ifdef CONFIG_PROC_FS
845 void vm_stat_account(struct mm_struct *mm, unsigned long flags,
846 struct file *file, long pages)
848 const unsigned long stack_flags
849 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
852 mm->shared_vm += pages;
853 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
854 mm->exec_vm += pages;
855 } else if (flags & stack_flags)
856 mm->stack_vm += pages;
857 if (flags & (VM_RESERVED|VM_IO))
858 mm->reserved_vm += pages;
860 #endif /* CONFIG_PROC_FS */
863 * The caller must hold down_write(current->mm->mmap_sem).
866 unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
867 unsigned long len, unsigned long prot,
868 unsigned long flags, unsigned long pgoff)
870 struct mm_struct * mm = current->mm;
871 struct vm_area_struct * vma, * prev;
873 unsigned int vm_flags;
874 int correct_wcount = 0;
876 struct rb_node ** rb_link, * rb_parent;
878 unsigned long charged = 0, reqprot = prot;
881 if (is_file_hugepages(file))
884 if (!file->f_op || !file->f_op->mmap)
887 if ((prot & PROT_EXEC) &&
888 (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
892 * Does the application expect PROT_READ to imply PROT_EXEC?
894 * (the exception is when the underlying filesystem is noexec
895 * mounted, in which case we dont add PROT_EXEC.)
897 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
898 if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)))
904 /* Careful about overflows.. */
905 len = PAGE_ALIGN(len);
906 if (!len || len > TASK_SIZE)
909 /* offset overflow? */
910 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
913 /* Too many mappings? */
914 if (mm->map_count > sysctl_max_map_count)
917 /* Obtain the address to map to. we verify (or select) it and ensure
918 * that it represents a valid section of the address space.
920 addr = get_unmapped_area(file, addr, len, pgoff, flags);
921 if (addr & ~PAGE_MASK)
924 /* Do simple checking here so the lower-level routines won't have
925 * to. we assume access permissions have been handled by the open
926 * of the memory object, so we don't do any here.
928 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
929 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
931 if (flags & MAP_LOCKED) {
934 vm_flags |= VM_LOCKED;
936 /* mlock MCL_FUTURE? */
937 if (vm_flags & VM_LOCKED) {
938 unsigned long locked, lock_limit;
939 locked = len >> PAGE_SHIFT;
940 locked += mm->locked_vm;
941 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
942 lock_limit >>= PAGE_SHIFT;
943 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
947 inode = file ? file->f_dentry->d_inode : NULL;
950 switch (flags & MAP_TYPE) {
952 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
956 * Make sure we don't allow writing to an append-only
959 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
963 * Make sure there are no mandatory locks on the file.
965 if (locks_verify_locked(inode))
968 vm_flags |= VM_SHARED | VM_MAYSHARE;
969 if (!(file->f_mode & FMODE_WRITE))
970 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
974 if (!(file->f_mode & FMODE_READ))
982 switch (flags & MAP_TYPE) {
984 vm_flags |= VM_SHARED | VM_MAYSHARE;
988 * Set pgoff according to addr for anon_vma.
990 pgoff = addr >> PAGE_SHIFT;
997 error = security_file_mmap(file, reqprot, prot, flags);
1001 /* Clear old maps */
1004 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1005 if (vma && vma->vm_start < addr + len) {
1006 if (do_munmap(mm, addr, len))
1011 /* Check against address space limit. */
1012 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
1015 if (accountable && (!(flags & MAP_NORESERVE) ||
1016 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1017 if (vm_flags & VM_SHARED) {
1018 /* Check memory availability in shmem_file_setup? */
1019 vm_flags |= VM_ACCOUNT;
1020 } else if (vm_flags & VM_WRITE) {
1022 * Private writable mapping: check memory availability
1024 charged = len >> PAGE_SHIFT;
1025 if (security_vm_enough_memory(charged))
1027 vm_flags |= VM_ACCOUNT;
1032 * Can we just expand an old private anonymous mapping?
1033 * The VM_SHARED test is necessary because shmem_zero_setup
1034 * will create the file object for a shared anonymous map below.
1036 if (!file && !(vm_flags & VM_SHARED) &&
1037 vma_merge(mm, prev, addr, addr + len, vm_flags,
1038 NULL, NULL, pgoff, NULL))
1042 * Determine the object being mapped and call the appropriate
1043 * specific mapper. the address has already been validated, but
1044 * not unmapped, but the maps are removed from the list.
1046 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1053 vma->vm_start = addr;
1054 vma->vm_end = addr + len;
1055 vma->vm_flags = vm_flags;
1056 vma->vm_page_prot = protection_map[vm_flags & 0x0f];
1057 vma->vm_pgoff = pgoff;
1061 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1063 if (vm_flags & VM_DENYWRITE) {
1064 error = deny_write_access(file);
1069 vma->vm_file = file;
1071 error = file->f_op->mmap(file, vma);
1073 goto unmap_and_free_vma;
1074 } else if (vm_flags & VM_SHARED) {
1075 error = shmem_zero_setup(vma);
1080 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1081 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1082 * that memory reservation must be checked; but that reservation
1083 * belongs to shared memory object, not to vma: so now clear it.
1085 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1086 vma->vm_flags &= ~VM_ACCOUNT;
1088 /* Can addr have changed??
1090 * Answer: Yes, several device drivers can do it in their
1091 * f_op->mmap method. -DaveM
1093 addr = vma->vm_start;
1094 pgoff = vma->vm_pgoff;
1095 vm_flags = vma->vm_flags;
1097 if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
1098 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
1099 file = vma->vm_file;
1100 vma_link(mm, vma, prev, rb_link, rb_parent);
1102 atomic_inc(&inode->i_writecount);
1106 atomic_inc(&inode->i_writecount);
1109 mpol_free(vma_policy(vma));
1110 kmem_cache_free(vm_area_cachep, vma);
1113 mm->total_vm += len >> PAGE_SHIFT;
1114 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
1115 if (vm_flags & VM_LOCKED) {
1116 mm->locked_vm += len >> PAGE_SHIFT;
1117 make_pages_present(addr, addr + len);
1119 if (flags & MAP_POPULATE) {
1120 up_write(&mm->mmap_sem);
1121 sys_remap_file_pages(addr, len, 0,
1122 pgoff, flags & MAP_NONBLOCK);
1123 down_write(&mm->mmap_sem);
1129 atomic_inc(&inode->i_writecount);
1130 vma->vm_file = NULL;
1133 /* Undo any partial mapping done by a device driver. */
1134 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1137 kmem_cache_free(vm_area_cachep, vma);
1140 vm_unacct_memory(charged);
1144 EXPORT_SYMBOL(do_mmap_pgoff);
1146 /* Get an address range which is currently unmapped.
1147 * For shmat() with addr=0.
1149 * Ugly calling convention alert:
1150 * Return value with the low bits set means error value,
1152 * if (ret & ~PAGE_MASK)
1155 * This function "knows" that -ENOMEM has the bits set.
1157 #ifndef HAVE_ARCH_UNMAPPED_AREA
1159 arch_get_unmapped_area(struct file *filp, unsigned long addr,
1160 unsigned long len, unsigned long pgoff, unsigned long flags)
1162 struct mm_struct *mm = current->mm;
1163 struct vm_area_struct *vma;
1164 unsigned long start_addr;
1166 if (len > TASK_SIZE)
1170 addr = PAGE_ALIGN(addr);
1171 vma = find_vma(mm, addr);
1172 if (TASK_SIZE - len >= addr &&
1173 (!vma || addr + len <= vma->vm_start))
1176 if (len > mm->cached_hole_size) {
1177 start_addr = addr = mm->free_area_cache;
1179 start_addr = addr = TASK_UNMAPPED_BASE;
1180 mm->cached_hole_size = 0;
1184 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1185 /* At this point: (!vma || addr < vma->vm_end). */
1186 if (TASK_SIZE - len < addr) {
1188 * Start a new search - just in case we missed
1191 if (start_addr != TASK_UNMAPPED_BASE) {
1192 addr = TASK_UNMAPPED_BASE;
1194 mm->cached_hole_size = 0;
1199 if (!vma || addr + len <= vma->vm_start) {
1201 * Remember the place where we stopped the search:
1203 mm->free_area_cache = addr + len;
1206 if (addr + mm->cached_hole_size < vma->vm_start)
1207 mm->cached_hole_size = vma->vm_start - addr;
1213 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1216 * Is this a new hole at the lowest possible address?
1218 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1219 mm->free_area_cache = addr;
1220 mm->cached_hole_size = ~0UL;
1225 * This mmap-allocator allocates new areas top-down from below the
1226 * stack's low limit (the base):
1228 #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1230 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1231 const unsigned long len, const unsigned long pgoff,
1232 const unsigned long flags)
1234 struct vm_area_struct *vma;
1235 struct mm_struct *mm = current->mm;
1236 unsigned long addr = addr0;
1238 /* requested length too big for entire address space */
1239 if (len > TASK_SIZE)
1242 /* requesting a specific address */
1244 addr = PAGE_ALIGN(addr);
1245 vma = find_vma(mm, addr);
1246 if (TASK_SIZE - len >= addr &&
1247 (!vma || addr + len <= vma->vm_start))
1251 /* check if free_area_cache is useful for us */
1252 if (len <= mm->cached_hole_size) {
1253 mm->cached_hole_size = 0;
1254 mm->free_area_cache = mm->mmap_base;
1257 /* either no address requested or can't fit in requested address hole */
1258 addr = mm->free_area_cache;
1260 /* make sure it can fit in the remaining address space */
1262 vma = find_vma(mm, addr-len);
1263 if (!vma || addr <= vma->vm_start)
1264 /* remember the address as a hint for next time */
1265 return (mm->free_area_cache = addr-len);
1268 if (mm->mmap_base < len)
1271 addr = mm->mmap_base-len;
1275 * Lookup failure means no vma is above this address,
1276 * else if new region fits below vma->vm_start,
1277 * return with success:
1279 vma = find_vma(mm, addr);
1280 if (!vma || addr+len <= vma->vm_start)
1281 /* remember the address as a hint for next time */
1282 return (mm->free_area_cache = addr);
1284 /* remember the largest hole we saw so far */
1285 if (addr + mm->cached_hole_size < vma->vm_start)
1286 mm->cached_hole_size = vma->vm_start - addr;
1288 /* try just below the current vma->vm_start */
1289 addr = vma->vm_start-len;
1290 } while (len < vma->vm_start);
1294 * A failed mmap() very likely causes application failure,
1295 * so fall back to the bottom-up function here. This scenario
1296 * can happen with large stack limits and large mmap()
1299 mm->cached_hole_size = ~0UL;
1300 mm->free_area_cache = TASK_UNMAPPED_BASE;
1301 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1303 * Restore the topdown base:
1305 mm->free_area_cache = mm->mmap_base;
1306 mm->cached_hole_size = ~0UL;
1312 void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
1315 * Is this a new hole at the highest possible address?
1317 if (addr > mm->free_area_cache)
1318 mm->free_area_cache = addr;
1320 /* dont allow allocations above current base */
1321 if (mm->free_area_cache > mm->mmap_base)
1322 mm->free_area_cache = mm->mmap_base;
1326 get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1327 unsigned long pgoff, unsigned long flags)
1331 if (!(flags & MAP_FIXED)) {
1332 unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
1334 get_area = current->mm->get_unmapped_area;
1335 if (file && file->f_op && file->f_op->get_unmapped_area)
1336 get_area = file->f_op->get_unmapped_area;
1337 addr = get_area(file, addr, len, pgoff, flags);
1338 if (IS_ERR_VALUE(addr))
1342 if (addr > TASK_SIZE - len)
1344 if (addr & ~PAGE_MASK)
1346 if (file && is_file_hugepages(file)) {
1348 * Check if the given range is hugepage aligned, and
1349 * can be made suitable for hugepages.
1351 ret = prepare_hugepage_range(addr, len);
1354 * Ensure that a normal request is not falling in a
1355 * reserved hugepage range. For some archs like IA-64,
1356 * there is a separate region for hugepages.
1358 ret = is_hugepage_only_range(current->mm, addr, len);
1365 EXPORT_SYMBOL(get_unmapped_area);
1367 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1368 struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1370 struct vm_area_struct *vma = NULL;
1373 /* Check the cache first. */
1374 /* (Cache hit rate is typically around 35%.) */
1375 vma = mm->mmap_cache;
1376 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1377 struct rb_node * rb_node;
1379 rb_node = mm->mm_rb.rb_node;
1383 struct vm_area_struct * vma_tmp;
1385 vma_tmp = rb_entry(rb_node,
1386 struct vm_area_struct, vm_rb);
1388 if (vma_tmp->vm_end > addr) {
1390 if (vma_tmp->vm_start <= addr)
1392 rb_node = rb_node->rb_left;
1394 rb_node = rb_node->rb_right;
1397 mm->mmap_cache = vma;
1403 EXPORT_SYMBOL(find_vma);
1405 /* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1406 struct vm_area_struct *
1407 find_vma_prev(struct mm_struct *mm, unsigned long addr,
1408 struct vm_area_struct **pprev)
1410 struct vm_area_struct *vma = NULL, *prev = NULL;
1411 struct rb_node * rb_node;
1415 /* Guard against addr being lower than the first VMA */
1418 /* Go through the RB tree quickly. */
1419 rb_node = mm->mm_rb.rb_node;
1422 struct vm_area_struct *vma_tmp;
1423 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1425 if (addr < vma_tmp->vm_end) {
1426 rb_node = rb_node->rb_left;
1429 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1431 rb_node = rb_node->rb_right;
1437 return prev ? prev->vm_next : vma;
1441 * Verify that the stack growth is acceptable and
1442 * update accounting. This is shared with both the
1443 * grow-up and grow-down cases.
1445 static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1447 struct mm_struct *mm = vma->vm_mm;
1448 struct rlimit *rlim = current->signal->rlim;
1450 /* address space limit tests */
1451 if (!may_expand_vm(mm, grow))
1454 /* Stack limit test */
1455 if (size > rlim[RLIMIT_STACK].rlim_cur)
1458 /* mlock limit tests */
1459 if (vma->vm_flags & VM_LOCKED) {
1460 unsigned long locked;
1461 unsigned long limit;
1462 locked = mm->locked_vm + grow;
1463 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1464 if (locked > limit && !capable(CAP_IPC_LOCK))
1469 * Overcommit.. This must be the final test, as it will
1470 * update security statistics.
1472 if (security_vm_enough_memory(grow))
1475 /* Ok, everything looks good - let it rip */
1476 mm->total_vm += grow;
1477 if (vma->vm_flags & VM_LOCKED)
1478 mm->locked_vm += grow;
1479 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
1483 #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
1485 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1486 * vma is the last one with address > vma->vm_end. Have to extend vma.
1491 int expand_upwards(struct vm_area_struct *vma, unsigned long address)
1495 if (!(vma->vm_flags & VM_GROWSUP))
1499 * We must make sure the anon_vma is allocated
1500 * so that the anon_vma locking is not a noop.
1502 if (unlikely(anon_vma_prepare(vma)))
1507 * vma->vm_start/vm_end cannot change under us because the caller
1508 * is required to hold the mmap_sem in read mode. We need the
1509 * anon_vma lock to serialize against concurrent expand_stacks.
1511 address += 4 + PAGE_SIZE - 1;
1512 address &= PAGE_MASK;
1515 /* Somebody else might have raced and expanded it already */
1516 if (address > vma->vm_end) {
1517 unsigned long size, grow;
1519 size = address - vma->vm_start;
1520 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1522 error = acct_stack_growth(vma, size, grow);
1524 vma->vm_end = address;
1526 anon_vma_unlock(vma);
1529 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1531 #ifdef CONFIG_STACK_GROWSUP
1532 int expand_stack(struct vm_area_struct *vma, unsigned long address)
1534 return expand_upwards(vma, address);
1537 struct vm_area_struct *
1538 find_extend_vma(struct mm_struct *mm, unsigned long addr)
1540 struct vm_area_struct *vma, *prev;
1543 vma = find_vma_prev(mm, addr, &prev);
1544 if (vma && (vma->vm_start <= addr))
1546 if (!prev || expand_stack(prev, addr))
1548 if (prev->vm_flags & VM_LOCKED) {
1549 make_pages_present(addr, prev->vm_end);
1555 * vma is the first one with address < vma->vm_start. Have to extend vma.
1557 int expand_stack(struct vm_area_struct *vma, unsigned long address)
1562 * We must make sure the anon_vma is allocated
1563 * so that the anon_vma locking is not a noop.
1565 if (unlikely(anon_vma_prepare(vma)))
1570 * vma->vm_start/vm_end cannot change under us because the caller
1571 * is required to hold the mmap_sem in read mode. We need the
1572 * anon_vma lock to serialize against concurrent expand_stacks.
1574 address &= PAGE_MASK;
1577 /* Somebody else might have raced and expanded it already */
1578 if (address < vma->vm_start) {
1579 unsigned long size, grow;
1581 size = vma->vm_end - address;
1582 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1584 error = acct_stack_growth(vma, size, grow);
1586 vma->vm_start = address;
1587 vma->vm_pgoff -= grow;
1590 anon_vma_unlock(vma);
1594 struct vm_area_struct *
1595 find_extend_vma(struct mm_struct * mm, unsigned long addr)
1597 struct vm_area_struct * vma;
1598 unsigned long start;
1601 vma = find_vma(mm,addr);
1604 if (vma->vm_start <= addr)
1606 if (!(vma->vm_flags & VM_GROWSDOWN))
1608 start = vma->vm_start;
1609 if (expand_stack(vma, addr))
1611 if (vma->vm_flags & VM_LOCKED) {
1612 make_pages_present(addr, start);
1619 * Ok - we have the memory areas we should free on the vma list,
1620 * so release them, and do the vma updates.
1622 * Called with the mm semaphore held.
1624 static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
1626 /* Update high watermark before we lower total_vm */
1627 update_hiwater_vm(mm);
1629 long nrpages = vma_pages(vma);
1631 mm->total_vm -= nrpages;
1632 if (vma->vm_flags & VM_LOCKED)
1633 mm->locked_vm -= nrpages;
1634 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
1635 vma = remove_vma(vma);
1641 * Get rid of page table information in the indicated region.
1643 * Called with the mm semaphore held.
1645 static void unmap_region(struct mm_struct *mm,
1646 struct vm_area_struct *vma, struct vm_area_struct *prev,
1647 unsigned long start, unsigned long end)
1649 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
1650 struct mmu_gather *tlb;
1651 unsigned long nr_accounted = 0;
1654 tlb = tlb_gather_mmu(mm, 0);
1655 update_hiwater_rss(mm);
1656 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
1657 vm_unacct_memory(nr_accounted);
1658 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
1659 next? next->vm_start: 0);
1660 tlb_finish_mmu(tlb, start, end);
1664 * Create a list of vma's touched by the unmap, removing them from the mm's
1665 * vma list as we go..
1668 detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1669 struct vm_area_struct *prev, unsigned long end)
1671 struct vm_area_struct **insertion_point;
1672 struct vm_area_struct *tail_vma = NULL;
1675 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1677 rb_erase(&vma->vm_rb, &mm->mm_rb);
1681 } while (vma && vma->vm_start < end);
1682 *insertion_point = vma;
1683 tail_vma->vm_next = NULL;
1684 if (mm->unmap_area == arch_unmap_area)
1685 addr = prev ? prev->vm_end : mm->mmap_base;
1687 addr = vma ? vma->vm_start : mm->mmap_base;
1688 mm->unmap_area(mm, addr);
1689 mm->mmap_cache = NULL; /* Kill the cache. */
1693 * Split a vma into two pieces at address 'addr', a new vma is allocated
1694 * either for the first part or the the tail.
1696 int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1697 unsigned long addr, int new_below)
1699 struct mempolicy *pol;
1700 struct vm_area_struct *new;
1702 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1705 if (mm->map_count >= sysctl_max_map_count)
1708 new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
1712 /* most fields are the same, copy all, and then fixup */
1718 new->vm_start = addr;
1719 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1722 pol = mpol_copy(vma_policy(vma));
1724 kmem_cache_free(vm_area_cachep, new);
1725 return PTR_ERR(pol);
1727 vma_set_policy(new, pol);
1730 get_file(new->vm_file);
1732 if (new->vm_ops && new->vm_ops->open)
1733 new->vm_ops->open(new);
1736 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1737 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1739 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1744 /* Munmap is split into 2 main parts -- this part which finds
1745 * what needs doing, and the areas themselves, which do the
1746 * work. This now handles partial unmappings.
1747 * Jeremy Fitzhardinge <jeremy@goop.org>
1749 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1752 struct vm_area_struct *vma, *prev, *last;
1754 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1757 if ((len = PAGE_ALIGN(len)) == 0)
1760 /* Find the first overlapping VMA */
1761 vma = find_vma_prev(mm, start, &prev);
1764 /* we have start < vma->vm_end */
1766 /* if it doesn't overlap, we have nothing.. */
1768 if (vma->vm_start >= end)
1772 * If we need to split any vma, do it now to save pain later.
1774 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1775 * unmapped vm_area_struct will remain in use: so lower split_vma
1776 * places tmp vma above, and higher split_vma places tmp vma below.
1778 if (start > vma->vm_start) {
1779 int error = split_vma(mm, vma, start, 0);
1785 /* Does it split the last one? */
1786 last = find_vma(mm, end);
1787 if (last && end > last->vm_start) {
1788 int error = split_vma(mm, last, end, 1);
1792 vma = prev? prev->vm_next: mm->mmap;
1795 * Remove the vma's, and unmap the actual pages
1797 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1798 unmap_region(mm, vma, prev, start, end);
1800 /* Fix up all other VM information */
1801 remove_vma_list(mm, vma);
1806 EXPORT_SYMBOL(do_munmap);
1808 asmlinkage long sys_munmap(unsigned long addr, size_t len)
1811 struct mm_struct *mm = current->mm;
1813 profile_munmap(addr);
1815 down_write(&mm->mmap_sem);
1816 ret = do_munmap(mm, addr, len);
1817 up_write(&mm->mmap_sem);
1821 static inline void verify_mm_writelocked(struct mm_struct *mm)
1823 #ifdef CONFIG_DEBUG_VM
1824 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1826 up_read(&mm->mmap_sem);
1832 * this is really a simplified "do_mmap". it only handles
1833 * anonymous maps. eventually we may be able to do some
1834 * brk-specific accounting here.
1836 unsigned long do_brk(unsigned long addr, unsigned long len)
1838 struct mm_struct * mm = current->mm;
1839 struct vm_area_struct * vma, * prev;
1840 unsigned long flags;
1841 struct rb_node ** rb_link, * rb_parent;
1842 pgoff_t pgoff = addr >> PAGE_SHIFT;
1844 len = PAGE_ALIGN(len);
1848 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1854 if (mm->def_flags & VM_LOCKED) {
1855 unsigned long locked, lock_limit;
1856 locked = len >> PAGE_SHIFT;
1857 locked += mm->locked_vm;
1858 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
1859 lock_limit >>= PAGE_SHIFT;
1860 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1865 * mm->mmap_sem is required to protect against another thread
1866 * changing the mappings in case we sleep.
1868 verify_mm_writelocked(mm);
1871 * Clear old maps. this also does some error checking for us
1874 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1875 if (vma && vma->vm_start < addr + len) {
1876 if (do_munmap(mm, addr, len))
1881 /* Check against address space limits *after* clearing old maps... */
1882 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
1885 if (mm->map_count > sysctl_max_map_count)
1888 if (security_vm_enough_memory(len >> PAGE_SHIFT))
1891 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1893 /* Can we just expand an old private anonymous mapping? */
1894 if (vma_merge(mm, prev, addr, addr + len, flags,
1895 NULL, NULL, pgoff, NULL))
1899 * create a vma struct for an anonymous mapping
1901 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1903 vm_unacct_memory(len >> PAGE_SHIFT);
1908 vma->vm_start = addr;
1909 vma->vm_end = addr + len;
1910 vma->vm_pgoff = pgoff;
1911 vma->vm_flags = flags;
1912 vma->vm_page_prot = protection_map[flags & 0x0f];
1913 vma_link(mm, vma, prev, rb_link, rb_parent);
1915 mm->total_vm += len >> PAGE_SHIFT;
1916 if (flags & VM_LOCKED) {
1917 mm->locked_vm += len >> PAGE_SHIFT;
1918 make_pages_present(addr, addr + len);
1923 EXPORT_SYMBOL(do_brk);
1925 /* Release all mmaps. */
1926 void exit_mmap(struct mm_struct *mm)
1928 struct mmu_gather *tlb;
1929 struct vm_area_struct *vma = mm->mmap;
1930 unsigned long nr_accounted = 0;
1935 tlb = tlb_gather_mmu(mm, 1);
1936 /* Don't update_hiwater_rss(mm) here, do_exit already did */
1937 /* Use -1 here to ensure all VMAs in the mm are unmapped */
1938 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
1939 vm_unacct_memory(nr_accounted);
1940 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
1941 tlb_finish_mmu(tlb, 0, end);
1944 * Walk the list again, actually closing and freeing it,
1945 * with preemption enabled, without holding any MM locks.
1948 vma = remove_vma(vma);
1950 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
1953 /* Insert vm structure into process list sorted by address
1954 * and into the inode's i_mmap tree. If vm_file is non-NULL
1955 * then i_mmap_lock is taken here.
1957 int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
1959 struct vm_area_struct * __vma, * prev;
1960 struct rb_node ** rb_link, * rb_parent;
1963 * The vm_pgoff of a purely anonymous vma should be irrelevant
1964 * until its first write fault, when page's anon_vma and index
1965 * are set. But now set the vm_pgoff it will almost certainly
1966 * end up with (unless mremap moves it elsewhere before that
1967 * first wfault), so /proc/pid/maps tells a consistent story.
1969 * By setting it to reflect the virtual start address of the
1970 * vma, merges and splits can happen in a seamless way, just
1971 * using the existing file pgoff checks and manipulations.
1972 * Similarly in do_mmap_pgoff and in do_brk.
1974 if (!vma->vm_file) {
1975 BUG_ON(vma->anon_vma);
1976 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
1978 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
1979 if (__vma && __vma->vm_start < vma->vm_end)
1981 if ((vma->vm_flags & VM_ACCOUNT) &&
1982 security_vm_enough_memory(vma_pages(vma)))
1984 vma_link(mm, vma, prev, rb_link, rb_parent);
1989 * Copy the vma structure to a new location in the same mm,
1990 * prior to moving page table entries, to effect an mremap move.
1992 struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
1993 unsigned long addr, unsigned long len, pgoff_t pgoff)
1995 struct vm_area_struct *vma = *vmap;
1996 unsigned long vma_start = vma->vm_start;
1997 struct mm_struct *mm = vma->vm_mm;
1998 struct vm_area_struct *new_vma, *prev;
1999 struct rb_node **rb_link, *rb_parent;
2000 struct mempolicy *pol;
2003 * If anonymous vma has not yet been faulted, update new pgoff
2004 * to match new location, to increase its chance of merging.
2006 if (!vma->vm_file && !vma->anon_vma)
2007 pgoff = addr >> PAGE_SHIFT;
2009 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2010 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2011 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2014 * Source vma may have been merged into new_vma
2016 if (vma_start >= new_vma->vm_start &&
2017 vma_start < new_vma->vm_end)
2020 new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
2023 pol = mpol_copy(vma_policy(vma));
2025 kmem_cache_free(vm_area_cachep, new_vma);
2028 vma_set_policy(new_vma, pol);
2029 new_vma->vm_start = addr;
2030 new_vma->vm_end = addr + len;
2031 new_vma->vm_pgoff = pgoff;
2032 if (new_vma->vm_file)
2033 get_file(new_vma->vm_file);
2034 if (new_vma->vm_ops && new_vma->vm_ops->open)
2035 new_vma->vm_ops->open(new_vma);
2036 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2043 * Return true if the calling process may expand its vm space by the passed
2046 int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2048 unsigned long cur = mm->total_vm; /* pages */
2051 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2053 if (cur + npages > lim)