4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
41 #include <linux/kernel_stat.h>
43 #include <linux/hugetlb.h>
44 #include <linux/mman.h>
45 #include <linux/swap.h>
46 #include <linux/highmem.h>
47 #include <linux/pagemap.h>
48 #include <linux/rmap.h>
49 #include <linux/module.h>
50 #include <linux/init.h>
52 #include <asm/pgalloc.h>
53 #include <asm/uaccess.h>
55 #include <asm/tlbflush.h>
56 #include <asm/pgtable.h>
58 #include <linux/swapops.h>
59 #include <linux/elf.h>
61 #ifndef CONFIG_NEED_MULTIPLE_NODES
62 /* use the per-pgdat data instead for discontigmem - mbligh */
63 unsigned long max_mapnr
;
66 EXPORT_SYMBOL(max_mapnr
);
67 EXPORT_SYMBOL(mem_map
);
70 unsigned long num_physpages
;
72 * A number of key systems in x86 including ioremap() rely on the assumption
73 * that high_memory defines the upper bound on direct map memory, then end
74 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
75 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
79 unsigned long vmalloc_earlyreserve
;
81 EXPORT_SYMBOL(num_physpages
);
82 EXPORT_SYMBOL(high_memory
);
83 EXPORT_SYMBOL(vmalloc_earlyreserve
);
86 * If a p?d_bad entry is found while walking page tables, report
87 * the error, before resetting entry to p?d_none. Usually (but
88 * very seldom) called out from the p?d_none_or_clear_bad macros.
91 void pgd_clear_bad(pgd_t
*pgd
)
97 void pud_clear_bad(pud_t
*pud
)
103 void pmd_clear_bad(pmd_t
*pmd
)
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
113 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
)
115 struct page
*page
= pmd_page(*pmd
);
117 pte_free_tlb(tlb
, page
);
118 dec_page_state(nr_page_table_pages
);
122 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
123 unsigned long addr
, unsigned long end
,
124 unsigned long floor
, unsigned long ceiling
)
131 pmd
= pmd_offset(pud
, addr
);
133 next
= pmd_addr_end(addr
, end
);
134 if (pmd_none_or_clear_bad(pmd
))
136 free_pte_range(tlb
, pmd
);
137 } while (pmd
++, addr
= next
, addr
!= end
);
147 if (end
- 1 > ceiling
- 1)
150 pmd
= pmd_offset(pud
, start
);
152 pmd_free_tlb(tlb
, pmd
);
155 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
156 unsigned long addr
, unsigned long end
,
157 unsigned long floor
, unsigned long ceiling
)
164 pud
= pud_offset(pgd
, addr
);
166 next
= pud_addr_end(addr
, end
);
167 if (pud_none_or_clear_bad(pud
))
169 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
170 } while (pud
++, addr
= next
, addr
!= end
);
176 ceiling
&= PGDIR_MASK
;
180 if (end
- 1 > ceiling
- 1)
183 pud
= pud_offset(pgd
, start
);
185 pud_free_tlb(tlb
, pud
);
189 * This function frees user-level page tables of a process.
191 * Must be called with pagetable lock held.
193 void free_pgd_range(struct mmu_gather
**tlb
,
194 unsigned long addr
, unsigned long end
,
195 unsigned long floor
, unsigned long ceiling
)
202 * The next few lines have given us lots of grief...
204 * Why are we testing PMD* at this top level? Because often
205 * there will be no work to do at all, and we'd prefer not to
206 * go all the way down to the bottom just to discover that.
208 * Why all these "- 1"s? Because 0 represents both the bottom
209 * of the address space and the top of it (using -1 for the
210 * top wouldn't help much: the masks would do the wrong thing).
211 * The rule is that addr 0 and floor 0 refer to the bottom of
212 * the address space, but end 0 and ceiling 0 refer to the top
213 * Comparisons need to use "end - 1" and "ceiling - 1" (though
214 * that end 0 case should be mythical).
216 * Wherever addr is brought up or ceiling brought down, we must
217 * be careful to reject "the opposite 0" before it confuses the
218 * subsequent tests. But what about where end is brought down
219 * by PMD_SIZE below? no, end can't go down to 0 there.
221 * Whereas we round start (addr) and ceiling down, by different
222 * masks at different levels, in order to test whether a table
223 * now has no other vmas using it, so can be freed, we don't
224 * bother to round floor or end up - the tests don't need that.
238 if (end
- 1 > ceiling
- 1)
244 pgd
= pgd_offset((*tlb
)->mm
, addr
);
246 next
= pgd_addr_end(addr
, end
);
247 if (pgd_none_or_clear_bad(pgd
))
249 free_pud_range(*tlb
, pgd
, addr
, next
, floor
, ceiling
);
250 } while (pgd
++, addr
= next
, addr
!= end
);
252 if (!tlb_is_full_mm(*tlb
))
253 flush_tlb_pgtables((*tlb
)->mm
, start
, end
);
256 void free_pgtables(struct mmu_gather
**tlb
, struct vm_area_struct
*vma
,
257 unsigned long floor
, unsigned long ceiling
)
260 struct vm_area_struct
*next
= vma
->vm_next
;
261 unsigned long addr
= vma
->vm_start
;
263 if (is_hugepage_only_range(vma
->vm_mm
, addr
, HPAGE_SIZE
)) {
264 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
265 floor
, next
? next
->vm_start
: ceiling
);
268 * Optimization: gather nearby vmas into one call down
270 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
271 && !is_hugepage_only_range(vma
->vm_mm
, next
->vm_start
,
276 free_pgd_range(tlb
, addr
, vma
->vm_end
,
277 floor
, next
? next
->vm_start
: ceiling
);
283 pte_t fastcall
*pte_alloc_map(struct mm_struct
*mm
, pmd_t
*pmd
,
284 unsigned long address
)
286 if (!pmd_present(*pmd
)) {
289 spin_unlock(&mm
->page_table_lock
);
290 new = pte_alloc_one(mm
, address
);
291 spin_lock(&mm
->page_table_lock
);
295 * Because we dropped the lock, we should re-check the
296 * entry, as somebody else could have populated it..
298 if (pmd_present(*pmd
)) {
303 inc_page_state(nr_page_table_pages
);
304 pmd_populate(mm
, pmd
, new);
307 return pte_offset_map(pmd
, address
);
310 pte_t fastcall
* pte_alloc_kernel(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
312 if (!pmd_present(*pmd
)) {
315 spin_unlock(&mm
->page_table_lock
);
316 new = pte_alloc_one_kernel(mm
, address
);
317 spin_lock(&mm
->page_table_lock
);
322 * Because we dropped the lock, we should re-check the
323 * entry, as somebody else could have populated it..
325 if (pmd_present(*pmd
)) {
326 pte_free_kernel(new);
329 pmd_populate_kernel(mm
, pmd
, new);
332 return pte_offset_kernel(pmd
, address
);
336 * copy one vm_area from one task to the other. Assumes the page tables
337 * already present in the new task to be cleared in the whole range
338 * covered by this vma.
340 * dst->page_table_lock is held on entry and exit,
341 * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
345 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
346 pte_t
*dst_pte
, pte_t
*src_pte
, unsigned long vm_flags
,
349 pte_t pte
= *src_pte
;
353 /* pte contains position in swap or file, so copy. */
354 if (unlikely(!pte_present(pte
))) {
355 if (!pte_file(pte
)) {
356 swap_duplicate(pte_to_swp_entry(pte
));
357 /* make sure dst_mm is on swapoff's mmlist. */
358 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
359 spin_lock(&mmlist_lock
);
360 list_add(&dst_mm
->mmlist
, &src_mm
->mmlist
);
361 spin_unlock(&mmlist_lock
);
364 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
369 /* the pte points outside of valid memory, the
370 * mapping is assumed to be good, meaningful
371 * and not mapped via rmap - duplicate the
376 page
= pfn_to_page(pfn
);
378 if (!page
|| PageReserved(page
)) {
379 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
384 * If it's a COW mapping, write protect it both
385 * in the parent and the child
387 if ((vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
) {
388 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
393 * If it's a shared mapping, mark it clean in
396 if (vm_flags
& VM_SHARED
)
397 pte
= pte_mkclean(pte
);
398 pte
= pte_mkold(pte
);
400 inc_mm_counter(dst_mm
, rss
);
402 inc_mm_counter(dst_mm
, anon_rss
);
403 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
407 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
408 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
409 unsigned long addr
, unsigned long end
)
411 pte_t
*src_pte
, *dst_pte
;
412 unsigned long vm_flags
= vma
->vm_flags
;
416 dst_pte
= pte_alloc_map(dst_mm
, dst_pmd
, addr
);
419 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
422 spin_lock(&src_mm
->page_table_lock
);
425 * We are holding two locks at this point - either of them
426 * could generate latencies in another task on another CPU.
428 if (progress
>= 32 && (need_resched() ||
429 need_lockbreak(&src_mm
->page_table_lock
) ||
430 need_lockbreak(&dst_mm
->page_table_lock
)))
432 if (pte_none(*src_pte
)) {
436 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vm_flags
, addr
);
438 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
439 spin_unlock(&src_mm
->page_table_lock
);
441 pte_unmap_nested(src_pte
- 1);
442 pte_unmap(dst_pte
- 1);
443 cond_resched_lock(&dst_mm
->page_table_lock
);
449 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
450 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
451 unsigned long addr
, unsigned long end
)
453 pmd_t
*src_pmd
, *dst_pmd
;
456 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
459 src_pmd
= pmd_offset(src_pud
, addr
);
461 next
= pmd_addr_end(addr
, end
);
462 if (pmd_none_or_clear_bad(src_pmd
))
464 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
467 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
471 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
472 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
473 unsigned long addr
, unsigned long end
)
475 pud_t
*src_pud
, *dst_pud
;
478 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
481 src_pud
= pud_offset(src_pgd
, addr
);
483 next
= pud_addr_end(addr
, end
);
484 if (pud_none_or_clear_bad(src_pud
))
486 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
489 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
493 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
494 struct vm_area_struct
*vma
)
496 pgd_t
*src_pgd
, *dst_pgd
;
498 unsigned long addr
= vma
->vm_start
;
499 unsigned long end
= vma
->vm_end
;
501 if (is_vm_hugetlb_page(vma
))
502 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
504 dst_pgd
= pgd_offset(dst_mm
, addr
);
505 src_pgd
= pgd_offset(src_mm
, addr
);
507 next
= pgd_addr_end(addr
, end
);
508 if (pgd_none_or_clear_bad(src_pgd
))
510 if (copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
513 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
517 static void zap_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
,
518 unsigned long addr
, unsigned long end
,
519 struct zap_details
*details
)
523 pte
= pte_offset_map(pmd
, addr
);
528 if (pte_present(ptent
)) {
529 struct page
*page
= NULL
;
530 unsigned long pfn
= pte_pfn(ptent
);
531 if (pfn_valid(pfn
)) {
532 page
= pfn_to_page(pfn
);
533 if (PageReserved(page
))
536 if (unlikely(details
) && page
) {
538 * unmap_shared_mapping_pages() wants to
539 * invalidate cache without truncating:
540 * unmap shared but keep private pages.
542 if (details
->check_mapping
&&
543 details
->check_mapping
!= page
->mapping
)
546 * Each page->index must be checked when
547 * invalidating or truncating nonlinear.
549 if (details
->nonlinear_vma
&&
550 (page
->index
< details
->first_index
||
551 page
->index
> details
->last_index
))
554 ptent
= ptep_get_and_clear(tlb
->mm
, addr
, pte
);
555 tlb_remove_tlb_entry(tlb
, pte
, addr
);
558 if (unlikely(details
) && details
->nonlinear_vma
559 && linear_page_index(details
->nonlinear_vma
,
560 addr
) != page
->index
)
561 set_pte_at(tlb
->mm
, addr
, pte
,
562 pgoff_to_pte(page
->index
));
563 if (pte_dirty(ptent
))
564 set_page_dirty(page
);
566 dec_mm_counter(tlb
->mm
, anon_rss
);
567 else if (pte_young(ptent
))
568 mark_page_accessed(page
);
570 page_remove_rmap(page
);
571 tlb_remove_page(tlb
, page
);
575 * If details->check_mapping, we leave swap entries;
576 * if details->nonlinear_vma, we leave file entries.
578 if (unlikely(details
))
580 if (!pte_file(ptent
))
581 free_swap_and_cache(pte_to_swp_entry(ptent
));
582 pte_clear(tlb
->mm
, addr
, pte
);
583 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
587 static inline void zap_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
588 unsigned long addr
, unsigned long end
,
589 struct zap_details
*details
)
594 pmd
= pmd_offset(pud
, addr
);
596 next
= pmd_addr_end(addr
, end
);
597 if (pmd_none_or_clear_bad(pmd
))
599 zap_pte_range(tlb
, pmd
, addr
, next
, details
);
600 } while (pmd
++, addr
= next
, addr
!= end
);
603 static inline void zap_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
604 unsigned long addr
, unsigned long end
,
605 struct zap_details
*details
)
610 pud
= pud_offset(pgd
, addr
);
612 next
= pud_addr_end(addr
, end
);
613 if (pud_none_or_clear_bad(pud
))
615 zap_pmd_range(tlb
, pud
, addr
, next
, details
);
616 } while (pud
++, addr
= next
, addr
!= end
);
619 static void unmap_page_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
620 unsigned long addr
, unsigned long end
,
621 struct zap_details
*details
)
626 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
630 tlb_start_vma(tlb
, vma
);
631 pgd
= pgd_offset(vma
->vm_mm
, addr
);
633 next
= pgd_addr_end(addr
, end
);
634 if (pgd_none_or_clear_bad(pgd
))
636 zap_pud_range(tlb
, pgd
, addr
, next
, details
);
637 } while (pgd
++, addr
= next
, addr
!= end
);
638 tlb_end_vma(tlb
, vma
);
641 #ifdef CONFIG_PREEMPT
642 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
644 /* No preempt: go for improved straight-line efficiency */
645 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
649 * unmap_vmas - unmap a range of memory covered by a list of vma's
650 * @tlbp: address of the caller's struct mmu_gather
651 * @mm: the controlling mm_struct
652 * @vma: the starting vma
653 * @start_addr: virtual address at which to start unmapping
654 * @end_addr: virtual address at which to end unmapping
655 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
656 * @details: details of nonlinear truncation or shared cache invalidation
658 * Returns the end address of the unmapping (restart addr if interrupted).
660 * Unmap all pages in the vma list. Called under page_table_lock.
662 * We aim to not hold page_table_lock for too long (for scheduling latency
663 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
664 * return the ending mmu_gather to the caller.
666 * Only addresses between `start' and `end' will be unmapped.
668 * The VMA list must be sorted in ascending virtual address order.
670 * unmap_vmas() assumes that the caller will flush the whole unmapped address
671 * range after unmap_vmas() returns. So the only responsibility here is to
672 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
673 * drops the lock and schedules.
675 unsigned long unmap_vmas(struct mmu_gather
**tlbp
, struct mm_struct
*mm
,
676 struct vm_area_struct
*vma
, unsigned long start_addr
,
677 unsigned long end_addr
, unsigned long *nr_accounted
,
678 struct zap_details
*details
)
680 unsigned long zap_bytes
= ZAP_BLOCK_SIZE
;
681 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
682 int tlb_start_valid
= 0;
683 unsigned long start
= start_addr
;
684 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
685 int fullmm
= tlb_is_full_mm(*tlbp
);
687 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
690 start
= max(vma
->vm_start
, start_addr
);
691 if (start
>= vma
->vm_end
)
693 end
= min(vma
->vm_end
, end_addr
);
694 if (end
<= vma
->vm_start
)
697 if (vma
->vm_flags
& VM_ACCOUNT
)
698 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
700 while (start
!= end
) {
703 if (!tlb_start_valid
) {
708 if (is_vm_hugetlb_page(vma
)) {
710 unmap_hugepage_range(vma
, start
, end
);
712 block
= min(zap_bytes
, end
- start
);
713 unmap_page_range(*tlbp
, vma
, start
,
714 start
+ block
, details
);
719 if ((long)zap_bytes
> 0)
722 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
724 if (need_resched() ||
725 need_lockbreak(&mm
->page_table_lock
) ||
726 (i_mmap_lock
&& need_lockbreak(i_mmap_lock
))) {
728 /* must reset count of rss freed */
729 *tlbp
= tlb_gather_mmu(mm
, fullmm
);
732 spin_unlock(&mm
->page_table_lock
);
734 spin_lock(&mm
->page_table_lock
);
737 *tlbp
= tlb_gather_mmu(mm
, fullmm
);
739 zap_bytes
= ZAP_BLOCK_SIZE
;
743 return start
; /* which is now the end (or restart) address */
747 * zap_page_range - remove user pages in a given range
748 * @vma: vm_area_struct holding the applicable pages
749 * @address: starting address of pages to zap
750 * @size: number of bytes to zap
751 * @details: details of nonlinear truncation or shared cache invalidation
753 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
754 unsigned long size
, struct zap_details
*details
)
756 struct mm_struct
*mm
= vma
->vm_mm
;
757 struct mmu_gather
*tlb
;
758 unsigned long end
= address
+ size
;
759 unsigned long nr_accounted
= 0;
761 if (is_vm_hugetlb_page(vma
)) {
762 zap_hugepage_range(vma
, address
, size
);
767 spin_lock(&mm
->page_table_lock
);
768 tlb
= tlb_gather_mmu(mm
, 0);
769 end
= unmap_vmas(&tlb
, mm
, vma
, address
, end
, &nr_accounted
, details
);
770 tlb_finish_mmu(tlb
, address
, end
);
771 spin_unlock(&mm
->page_table_lock
);
776 * Do a quick page-table lookup for a single page.
777 * mm->page_table_lock must be held.
779 static struct page
*__follow_page(struct mm_struct
*mm
, unsigned long address
,
780 int read
, int write
, int accessed
)
789 page
= follow_huge_addr(mm
, address
, write
);
793 pgd
= pgd_offset(mm
, address
);
794 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
797 pud
= pud_offset(pgd
, address
);
798 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
801 pmd
= pmd_offset(pud
, address
);
802 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
805 return follow_huge_pmd(mm
, address
, pmd
, write
);
807 ptep
= pte_offset_map(pmd
, address
);
813 if (pte_present(pte
)) {
814 if (write
&& !pte_write(pte
))
816 if (read
&& !pte_read(pte
))
819 if (pfn_valid(pfn
)) {
820 page
= pfn_to_page(pfn
);
822 if (write
&& !pte_dirty(pte
) &&!PageDirty(page
))
823 set_page_dirty(page
);
824 mark_page_accessed(page
);
835 follow_page(struct mm_struct
*mm
, unsigned long address
, int write
)
837 return __follow_page(mm
, address
, 0, write
, 1);
841 * check_user_page_readable() can be called frm niterrupt context by oprofile,
842 * so we need to avoid taking any non-irq-safe locks
844 int check_user_page_readable(struct mm_struct
*mm
, unsigned long address
)
846 return __follow_page(mm
, address
, 1, 0, 0) != NULL
;
848 EXPORT_SYMBOL(check_user_page_readable
);
851 untouched_anonymous_page(struct mm_struct
* mm
, struct vm_area_struct
*vma
,
852 unsigned long address
)
858 /* Check if the vma is for an anonymous mapping. */
859 if (vma
->vm_ops
&& vma
->vm_ops
->nopage
)
862 /* Check if page directory entry exists. */
863 pgd
= pgd_offset(mm
, address
);
864 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
867 pud
= pud_offset(pgd
, address
);
868 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
871 /* Check if page middle directory entry exists. */
872 pmd
= pmd_offset(pud
, address
);
873 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
876 /* There is a pte slot for 'address' in 'mm'. */
880 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
881 unsigned long start
, int len
, int write
, int force
,
882 struct page
**pages
, struct vm_area_struct
**vmas
)
888 * Require read or write permissions.
889 * If 'force' is set, we only require the "MAY" flags.
891 flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
892 flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
896 struct vm_area_struct
* vma
;
898 vma
= find_extend_vma(mm
, start
);
899 if (!vma
&& in_gate_area(tsk
, start
)) {
900 unsigned long pg
= start
& PAGE_MASK
;
901 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
906 if (write
) /* user gate pages are read-only */
907 return i
? : -EFAULT
;
909 pgd
= pgd_offset_k(pg
);
911 pgd
= pgd_offset_gate(mm
, pg
);
912 BUG_ON(pgd_none(*pgd
));
913 pud
= pud_offset(pgd
, pg
);
914 BUG_ON(pud_none(*pud
));
915 pmd
= pmd_offset(pud
, pg
);
917 return i
? : -EFAULT
;
918 pte
= pte_offset_map(pmd
, pg
);
919 if (pte_none(*pte
)) {
921 return i
? : -EFAULT
;
924 pages
[i
] = pte_page(*pte
);
936 if (!vma
|| (vma
->vm_flags
& VM_IO
)
937 || !(flags
& vma
->vm_flags
))
938 return i
? : -EFAULT
;
940 if (is_vm_hugetlb_page(vma
)) {
941 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
945 spin_lock(&mm
->page_table_lock
);
947 int write_access
= write
;
950 cond_resched_lock(&mm
->page_table_lock
);
951 while (!(page
= follow_page(mm
, start
, write_access
))) {
953 * Shortcut for anonymous pages. We don't want
954 * to force the creation of pages tables for
955 * insanely big anonymously mapped areas that
956 * nobody touched so far. This is important
957 * for doing a core dump for these mappings.
959 if (!write
&& untouched_anonymous_page(mm
,vma
,start
)) {
960 page
= ZERO_PAGE(start
);
963 spin_unlock(&mm
->page_table_lock
);
964 switch (__handle_mm_fault(mm
, vma
, start
,
968 * do_wp_page has broken COW when
969 * necessary, even if maybe_mkwrite
970 * decided not to set pte_write
980 case VM_FAULT_SIGBUS
:
981 return i
? i
: -EFAULT
;
983 return i
? i
: -ENOMEM
;
987 spin_lock(&mm
->page_table_lock
);
991 flush_dcache_page(page
);
992 if (!PageReserved(page
))
993 page_cache_get(page
);
1000 } while (len
&& start
< vma
->vm_end
);
1001 spin_unlock(&mm
->page_table_lock
);
1005 EXPORT_SYMBOL(get_user_pages
);
1007 static int zeromap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1008 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1012 pte
= pte_alloc_map(mm
, pmd
, addr
);
1016 pte_t zero_pte
= pte_wrprotect(mk_pte(ZERO_PAGE(addr
), prot
));
1017 BUG_ON(!pte_none(*pte
));
1018 set_pte_at(mm
, addr
, pte
, zero_pte
);
1019 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1024 static inline int zeromap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1025 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1030 pmd
= pmd_alloc(mm
, pud
, addr
);
1034 next
= pmd_addr_end(addr
, end
);
1035 if (zeromap_pte_range(mm
, pmd
, addr
, next
, prot
))
1037 } while (pmd
++, addr
= next
, addr
!= end
);
1041 static inline int zeromap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1042 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1047 pud
= pud_alloc(mm
, pgd
, addr
);
1051 next
= pud_addr_end(addr
, end
);
1052 if (zeromap_pmd_range(mm
, pud
, addr
, next
, prot
))
1054 } while (pud
++, addr
= next
, addr
!= end
);
1058 int zeromap_page_range(struct vm_area_struct
*vma
,
1059 unsigned long addr
, unsigned long size
, pgprot_t prot
)
1063 unsigned long end
= addr
+ size
;
1064 struct mm_struct
*mm
= vma
->vm_mm
;
1067 BUG_ON(addr
>= end
);
1068 pgd
= pgd_offset(mm
, addr
);
1069 flush_cache_range(vma
, addr
, end
);
1070 spin_lock(&mm
->page_table_lock
);
1072 next
= pgd_addr_end(addr
, end
);
1073 err
= zeromap_pud_range(mm
, pgd
, addr
, next
, prot
);
1076 } while (pgd
++, addr
= next
, addr
!= end
);
1077 spin_unlock(&mm
->page_table_lock
);
1082 * maps a range of physical memory into the requested pages. the old
1083 * mappings are removed. any references to nonexistent pages results
1084 * in null mappings (currently treated as "copy-on-access")
1086 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1087 unsigned long addr
, unsigned long end
,
1088 unsigned long pfn
, pgprot_t prot
)
1092 pte
= pte_alloc_map(mm
, pmd
, addr
);
1096 BUG_ON(!pte_none(*pte
));
1097 if (!pfn_valid(pfn
) || PageReserved(pfn_to_page(pfn
)))
1098 set_pte_at(mm
, addr
, pte
, pfn_pte(pfn
, prot
));
1100 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1105 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1106 unsigned long addr
, unsigned long end
,
1107 unsigned long pfn
, pgprot_t prot
)
1112 pfn
-= addr
>> PAGE_SHIFT
;
1113 pmd
= pmd_alloc(mm
, pud
, addr
);
1117 next
= pmd_addr_end(addr
, end
);
1118 if (remap_pte_range(mm
, pmd
, addr
, next
,
1119 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1121 } while (pmd
++, addr
= next
, addr
!= end
);
1125 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1126 unsigned long addr
, unsigned long end
,
1127 unsigned long pfn
, pgprot_t prot
)
1132 pfn
-= addr
>> PAGE_SHIFT
;
1133 pud
= pud_alloc(mm
, pgd
, addr
);
1137 next
= pud_addr_end(addr
, end
);
1138 if (remap_pmd_range(mm
, pud
, addr
, next
,
1139 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1141 } while (pud
++, addr
= next
, addr
!= end
);
1145 /* Note: this is only safe if the mm semaphore is held when called. */
1146 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1147 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1151 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1152 struct mm_struct
*mm
= vma
->vm_mm
;
1156 * Physically remapped pages are special. Tell the
1157 * rest of the world about it:
1158 * VM_IO tells people not to look at these pages
1159 * (accesses can have side effects).
1160 * VM_RESERVED tells swapout not to try to touch
1163 vma
->vm_flags
|= VM_IO
| VM_RESERVED
;
1165 BUG_ON(addr
>= end
);
1166 pfn
-= addr
>> PAGE_SHIFT
;
1167 pgd
= pgd_offset(mm
, addr
);
1168 flush_cache_range(vma
, addr
, end
);
1169 spin_lock(&mm
->page_table_lock
);
1171 next
= pgd_addr_end(addr
, end
);
1172 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1173 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1176 } while (pgd
++, addr
= next
, addr
!= end
);
1177 spin_unlock(&mm
->page_table_lock
);
1180 EXPORT_SYMBOL(remap_pfn_range
);
1183 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1184 * servicing faults for write access. In the normal case, do always want
1185 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1186 * that do not have writing enabled, when used by access_process_vm.
1188 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1190 if (likely(vma
->vm_flags
& VM_WRITE
))
1191 pte
= pte_mkwrite(pte
);
1196 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1198 static inline void break_cow(struct vm_area_struct
* vma
, struct page
* new_page
, unsigned long address
,
1203 entry
= maybe_mkwrite(pte_mkdirty(mk_pte(new_page
, vma
->vm_page_prot
)),
1205 ptep_establish(vma
, address
, page_table
, entry
);
1206 update_mmu_cache(vma
, address
, entry
);
1207 lazy_mmu_prot_update(entry
);
1211 * This routine handles present pages, when users try to write
1212 * to a shared page. It is done by copying the page to a new address
1213 * and decrementing the shared-page counter for the old page.
1215 * Goto-purists beware: the only reason for goto's here is that it results
1216 * in better assembly code.. The "default" path will see no jumps at all.
1218 * Note that this routine assumes that the protection checks have been
1219 * done by the caller (the low-level page fault routine in most cases).
1220 * Thus we can safely just mark it writable once we've done any necessary
1223 * We also mark the page dirty at this point even though the page will
1224 * change only once the write actually happens. This avoids a few races,
1225 * and potentially makes it more efficient.
1227 * We hold the mm semaphore and the page_table_lock on entry and exit
1228 * with the page_table_lock released.
1230 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
* vma
,
1231 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
, pte_t pte
)
1233 struct page
*old_page
, *new_page
;
1234 unsigned long pfn
= pte_pfn(pte
);
1238 if (unlikely(!pfn_valid(pfn
))) {
1240 * This should really halt the system so it can be debugged or
1241 * at least the kernel stops what it's doing before it corrupts
1242 * data, but for the moment just pretend this is OOM.
1244 pte_unmap(page_table
);
1245 printk(KERN_ERR
"do_wp_page: bogus page at address %08lx\n",
1247 spin_unlock(&mm
->page_table_lock
);
1248 return VM_FAULT_OOM
;
1250 old_page
= pfn_to_page(pfn
);
1252 if (PageAnon(old_page
) && !TestSetPageLocked(old_page
)) {
1253 int reuse
= can_share_swap_page(old_page
);
1254 unlock_page(old_page
);
1256 flush_cache_page(vma
, address
, pfn
);
1257 entry
= maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte
)),
1259 ptep_set_access_flags(vma
, address
, page_table
, entry
, 1);
1260 update_mmu_cache(vma
, address
, entry
);
1261 lazy_mmu_prot_update(entry
);
1262 pte_unmap(page_table
);
1263 spin_unlock(&mm
->page_table_lock
);
1264 return VM_FAULT_MINOR
|VM_FAULT_WRITE
;
1267 pte_unmap(page_table
);
1270 * Ok, we need to copy. Oh, well..
1272 if (!PageReserved(old_page
))
1273 page_cache_get(old_page
);
1274 spin_unlock(&mm
->page_table_lock
);
1276 if (unlikely(anon_vma_prepare(vma
)))
1278 if (old_page
== ZERO_PAGE(address
)) {
1279 new_page
= alloc_zeroed_user_highpage(vma
, address
);
1283 new_page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1286 copy_user_highpage(new_page
, old_page
, address
);
1289 * Re-check the pte - we dropped the lock
1291 ret
= VM_FAULT_MINOR
;
1292 spin_lock(&mm
->page_table_lock
);
1293 page_table
= pte_offset_map(pmd
, address
);
1294 if (likely(pte_same(*page_table
, pte
))) {
1295 if (PageAnon(old_page
))
1296 dec_mm_counter(mm
, anon_rss
);
1297 if (PageReserved(old_page
))
1298 inc_mm_counter(mm
, rss
);
1300 page_remove_rmap(old_page
);
1301 flush_cache_page(vma
, address
, pfn
);
1302 break_cow(vma
, new_page
, address
, page_table
);
1303 lru_cache_add_active(new_page
);
1304 page_add_anon_rmap(new_page
, vma
, address
);
1306 /* Free the old page.. */
1307 new_page
= old_page
;
1308 ret
|= VM_FAULT_WRITE
;
1310 pte_unmap(page_table
);
1311 page_cache_release(new_page
);
1312 page_cache_release(old_page
);
1313 spin_unlock(&mm
->page_table_lock
);
1317 page_cache_release(old_page
);
1318 return VM_FAULT_OOM
;
1322 * Helper functions for unmap_mapping_range().
1324 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1326 * We have to restart searching the prio_tree whenever we drop the lock,
1327 * since the iterator is only valid while the lock is held, and anyway
1328 * a later vma might be split and reinserted earlier while lock dropped.
1330 * The list of nonlinear vmas could be handled more efficiently, using
1331 * a placeholder, but handle it in the same way until a need is shown.
1332 * It is important to search the prio_tree before nonlinear list: a vma
1333 * may become nonlinear and be shifted from prio_tree to nonlinear list
1334 * while the lock is dropped; but never shifted from list to prio_tree.
1336 * In order to make forward progress despite restarting the search,
1337 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1338 * quickly skip it next time around. Since the prio_tree search only
1339 * shows us those vmas affected by unmapping the range in question, we
1340 * can't efficiently keep all vmas in step with mapping->truncate_count:
1341 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1342 * mapping->truncate_count and vma->vm_truncate_count are protected by
1345 * In order to make forward progress despite repeatedly restarting some
1346 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1347 * and restart from that address when we reach that vma again. It might
1348 * have been split or merged, shrunk or extended, but never shifted: so
1349 * restart_addr remains valid so long as it remains in the vma's range.
1350 * unmap_mapping_range forces truncate_count to leap over page-aligned
1351 * values so we can save vma's restart_addr in its truncate_count field.
1353 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1355 static void reset_vma_truncate_counts(struct address_space
*mapping
)
1357 struct vm_area_struct
*vma
;
1358 struct prio_tree_iter iter
;
1360 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
1361 vma
->vm_truncate_count
= 0;
1362 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
1363 vma
->vm_truncate_count
= 0;
1366 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
1367 unsigned long start_addr
, unsigned long end_addr
,
1368 struct zap_details
*details
)
1370 unsigned long restart_addr
;
1374 restart_addr
= vma
->vm_truncate_count
;
1375 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
1376 start_addr
= restart_addr
;
1377 if (start_addr
>= end_addr
) {
1378 /* Top of vma has been split off since last time */
1379 vma
->vm_truncate_count
= details
->truncate_count
;
1384 restart_addr
= zap_page_range(vma
, start_addr
,
1385 end_addr
- start_addr
, details
);
1388 * We cannot rely on the break test in unmap_vmas:
1389 * on the one hand, we don't want to restart our loop
1390 * just because that broke out for the page_table_lock;
1391 * on the other hand, it does no test when vma is small.
1393 need_break
= need_resched() ||
1394 need_lockbreak(details
->i_mmap_lock
);
1396 if (restart_addr
>= end_addr
) {
1397 /* We have now completed this vma: mark it so */
1398 vma
->vm_truncate_count
= details
->truncate_count
;
1402 /* Note restart_addr in vma's truncate_count field */
1403 vma
->vm_truncate_count
= restart_addr
;
1408 spin_unlock(details
->i_mmap_lock
);
1410 spin_lock(details
->i_mmap_lock
);
1414 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
1415 struct zap_details
*details
)
1417 struct vm_area_struct
*vma
;
1418 struct prio_tree_iter iter
;
1419 pgoff_t vba
, vea
, zba
, zea
;
1422 vma_prio_tree_foreach(vma
, &iter
, root
,
1423 details
->first_index
, details
->last_index
) {
1424 /* Skip quickly over those we have already dealt with */
1425 if (vma
->vm_truncate_count
== details
->truncate_count
)
1428 vba
= vma
->vm_pgoff
;
1429 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
1430 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1431 zba
= details
->first_index
;
1434 zea
= details
->last_index
;
1438 if (unmap_mapping_range_vma(vma
,
1439 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
1440 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
1446 static inline void unmap_mapping_range_list(struct list_head
*head
,
1447 struct zap_details
*details
)
1449 struct vm_area_struct
*vma
;
1452 * In nonlinear VMAs there is no correspondence between virtual address
1453 * offset and file offset. So we must perform an exhaustive search
1454 * across *all* the pages in each nonlinear VMA, not just the pages
1455 * whose virtual address lies outside the file truncation point.
1458 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
1459 /* Skip quickly over those we have already dealt with */
1460 if (vma
->vm_truncate_count
== details
->truncate_count
)
1462 details
->nonlinear_vma
= vma
;
1463 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
1464 vma
->vm_end
, details
) < 0)
1470 * unmap_mapping_range - unmap the portion of all mmaps
1471 * in the specified address_space corresponding to the specified
1472 * page range in the underlying file.
1473 * @mapping: the address space containing mmaps to be unmapped.
1474 * @holebegin: byte in first page to unmap, relative to the start of
1475 * the underlying file. This will be rounded down to a PAGE_SIZE
1476 * boundary. Note that this is different from vmtruncate(), which
1477 * must keep the partial page. In contrast, we must get rid of
1479 * @holelen: size of prospective hole in bytes. This will be rounded
1480 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1482 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1483 * but 0 when invalidating pagecache, don't throw away private data.
1485 void unmap_mapping_range(struct address_space
*mapping
,
1486 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
1488 struct zap_details details
;
1489 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
1490 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1492 /* Check for overflow. */
1493 if (sizeof(holelen
) > sizeof(hlen
)) {
1495 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1496 if (holeend
& ~(long long)ULONG_MAX
)
1497 hlen
= ULONG_MAX
- hba
+ 1;
1500 details
.check_mapping
= even_cows
? NULL
: mapping
;
1501 details
.nonlinear_vma
= NULL
;
1502 details
.first_index
= hba
;
1503 details
.last_index
= hba
+ hlen
- 1;
1504 if (details
.last_index
< details
.first_index
)
1505 details
.last_index
= ULONG_MAX
;
1506 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
1508 spin_lock(&mapping
->i_mmap_lock
);
1510 /* serialize i_size write against truncate_count write */
1512 /* Protect against page faults, and endless unmapping loops */
1513 mapping
->truncate_count
++;
1515 * For archs where spin_lock has inclusive semantics like ia64
1516 * this smp_mb() will prevent to read pagetable contents
1517 * before the truncate_count increment is visible to
1521 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
1522 if (mapping
->truncate_count
== 0)
1523 reset_vma_truncate_counts(mapping
);
1524 mapping
->truncate_count
++;
1526 details
.truncate_count
= mapping
->truncate_count
;
1528 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
1529 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
1530 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
1531 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
1532 spin_unlock(&mapping
->i_mmap_lock
);
1534 EXPORT_SYMBOL(unmap_mapping_range
);
1537 * Handle all mappings that got truncated by a "truncate()"
1540 * NOTE! We have to be ready to update the memory sharing
1541 * between the file and the memory map for a potential last
1542 * incomplete page. Ugly, but necessary.
1544 int vmtruncate(struct inode
* inode
, loff_t offset
)
1546 struct address_space
*mapping
= inode
->i_mapping
;
1547 unsigned long limit
;
1549 if (inode
->i_size
< offset
)
1552 * truncation of in-use swapfiles is disallowed - it would cause
1553 * subsequent swapout to scribble on the now-freed blocks.
1555 if (IS_SWAPFILE(inode
))
1557 i_size_write(inode
, offset
);
1558 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
1559 truncate_inode_pages(mapping
, offset
);
1563 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
1564 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
1566 if (offset
> inode
->i_sb
->s_maxbytes
)
1568 i_size_write(inode
, offset
);
1571 if (inode
->i_op
&& inode
->i_op
->truncate
)
1572 inode
->i_op
->truncate(inode
);
1575 send_sig(SIGXFSZ
, current
, 0);
1582 EXPORT_SYMBOL(vmtruncate
);
1585 * Primitive swap readahead code. We simply read an aligned block of
1586 * (1 << page_cluster) entries in the swap area. This method is chosen
1587 * because it doesn't cost us any seek time. We also make sure to queue
1588 * the 'original' request together with the readahead ones...
1590 * This has been extended to use the NUMA policies from the mm triggering
1593 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1595 void swapin_readahead(swp_entry_t entry
, unsigned long addr
,struct vm_area_struct
*vma
)
1598 struct vm_area_struct
*next_vma
= vma
? vma
->vm_next
: NULL
;
1601 struct page
*new_page
;
1602 unsigned long offset
;
1605 * Get the number of handles we should do readahead io to.
1607 num
= valid_swaphandles(entry
, &offset
);
1608 for (i
= 0; i
< num
; offset
++, i
++) {
1609 /* Ok, do the async read-ahead now */
1610 new_page
= read_swap_cache_async(swp_entry(swp_type(entry
),
1611 offset
), vma
, addr
);
1614 page_cache_release(new_page
);
1617 * Find the next applicable VMA for the NUMA policy.
1623 if (addr
>= vma
->vm_end
) {
1625 next_vma
= vma
? vma
->vm_next
: NULL
;
1627 if (vma
&& addr
< vma
->vm_start
)
1630 if (next_vma
&& addr
>= next_vma
->vm_start
) {
1632 next_vma
= vma
->vm_next
;
1637 lru_add_drain(); /* Push any new pages onto the LRU now */
1641 * We hold the mm semaphore and the page_table_lock on entry and
1642 * should release the pagetable lock on exit..
1644 static int do_swap_page(struct mm_struct
* mm
,
1645 struct vm_area_struct
* vma
, unsigned long address
,
1646 pte_t
*page_table
, pmd_t
*pmd
, pte_t orig_pte
, int write_access
)
1649 swp_entry_t entry
= pte_to_swp_entry(orig_pte
);
1651 int ret
= VM_FAULT_MINOR
;
1653 pte_unmap(page_table
);
1654 spin_unlock(&mm
->page_table_lock
);
1655 page
= lookup_swap_cache(entry
);
1657 swapin_readahead(entry
, address
, vma
);
1658 page
= read_swap_cache_async(entry
, vma
, address
);
1661 * Back out if somebody else faulted in this pte while
1662 * we released the page table lock.
1664 spin_lock(&mm
->page_table_lock
);
1665 page_table
= pte_offset_map(pmd
, address
);
1666 if (likely(pte_same(*page_table
, orig_pte
)))
1669 ret
= VM_FAULT_MINOR
;
1670 pte_unmap(page_table
);
1671 spin_unlock(&mm
->page_table_lock
);
1675 /* Had to read the page from swap area: Major fault */
1676 ret
= VM_FAULT_MAJOR
;
1677 inc_page_state(pgmajfault
);
1681 mark_page_accessed(page
);
1685 * Back out if somebody else faulted in this pte while we
1686 * released the page table lock.
1688 spin_lock(&mm
->page_table_lock
);
1689 page_table
= pte_offset_map(pmd
, address
);
1690 if (unlikely(!pte_same(*page_table
, orig_pte
))) {
1691 ret
= VM_FAULT_MINOR
;
1695 if (unlikely(!PageUptodate(page
))) {
1696 ret
= VM_FAULT_SIGBUS
;
1700 /* The page isn't present yet, go ahead with the fault. */
1702 inc_mm_counter(mm
, rss
);
1703 pte
= mk_pte(page
, vma
->vm_page_prot
);
1704 if (write_access
&& can_share_swap_page(page
)) {
1705 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
1709 flush_icache_page(vma
, page
);
1710 set_pte_at(mm
, address
, page_table
, pte
);
1711 page_add_anon_rmap(page
, vma
, address
);
1715 remove_exclusive_swap_page(page
);
1719 if (do_wp_page(mm
, vma
, address
,
1720 page_table
, pmd
, pte
) == VM_FAULT_OOM
)
1725 /* No need to invalidate - it was non-present before */
1726 update_mmu_cache(vma
, address
, pte
);
1727 lazy_mmu_prot_update(pte
);
1728 pte_unmap(page_table
);
1729 spin_unlock(&mm
->page_table_lock
);
1733 pte_unmap(page_table
);
1734 spin_unlock(&mm
->page_table_lock
);
1736 page_cache_release(page
);
1741 * We are called with the MM semaphore and page_table_lock
1742 * spinlock held to protect against concurrent faults in
1743 * multithreaded programs.
1746 do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1747 pte_t
*page_table
, pmd_t
*pmd
, int write_access
,
1751 struct page
* page
= ZERO_PAGE(addr
);
1753 /* Read-only mapping of ZERO_PAGE. */
1754 entry
= pte_wrprotect(mk_pte(ZERO_PAGE(addr
), vma
->vm_page_prot
));
1756 /* ..except if it's a write access */
1758 /* Allocate our own private page. */
1759 pte_unmap(page_table
);
1760 spin_unlock(&mm
->page_table_lock
);
1762 if (unlikely(anon_vma_prepare(vma
)))
1764 page
= alloc_zeroed_user_highpage(vma
, addr
);
1768 spin_lock(&mm
->page_table_lock
);
1769 page_table
= pte_offset_map(pmd
, addr
);
1771 if (!pte_none(*page_table
)) {
1772 pte_unmap(page_table
);
1773 page_cache_release(page
);
1774 spin_unlock(&mm
->page_table_lock
);
1777 inc_mm_counter(mm
, rss
);
1778 entry
= maybe_mkwrite(pte_mkdirty(mk_pte(page
,
1779 vma
->vm_page_prot
)),
1781 lru_cache_add_active(page
);
1782 SetPageReferenced(page
);
1783 page_add_anon_rmap(page
, vma
, addr
);
1786 set_pte_at(mm
, addr
, page_table
, entry
);
1787 pte_unmap(page_table
);
1789 /* No need to invalidate - it was non-present before */
1790 update_mmu_cache(vma
, addr
, entry
);
1791 lazy_mmu_prot_update(entry
);
1792 spin_unlock(&mm
->page_table_lock
);
1794 return VM_FAULT_MINOR
;
1796 return VM_FAULT_OOM
;
1800 * do_no_page() tries to create a new page mapping. It aggressively
1801 * tries to share with existing pages, but makes a separate copy if
1802 * the "write_access" parameter is true in order to avoid the next
1805 * As this is called only for pages that do not currently exist, we
1806 * do not need to flush old virtual caches or the TLB.
1808 * This is called with the MM semaphore held and the page table
1809 * spinlock held. Exit with the spinlock released.
1812 do_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1813 unsigned long address
, int write_access
, pte_t
*page_table
, pmd_t
*pmd
)
1815 struct page
* new_page
;
1816 struct address_space
*mapping
= NULL
;
1818 unsigned int sequence
= 0;
1819 int ret
= VM_FAULT_MINOR
;
1822 if (!vma
->vm_ops
|| !vma
->vm_ops
->nopage
)
1823 return do_anonymous_page(mm
, vma
, page_table
,
1824 pmd
, write_access
, address
);
1825 pte_unmap(page_table
);
1826 spin_unlock(&mm
->page_table_lock
);
1829 mapping
= vma
->vm_file
->f_mapping
;
1830 sequence
= mapping
->truncate_count
;
1831 smp_rmb(); /* serializes i_size against truncate_count */
1835 new_page
= vma
->vm_ops
->nopage(vma
, address
& PAGE_MASK
, &ret
);
1837 * No smp_rmb is needed here as long as there's a full
1838 * spin_lock/unlock sequence inside the ->nopage callback
1839 * (for the pagecache lookup) that acts as an implicit
1840 * smp_mb() and prevents the i_size read to happen
1841 * after the next truncate_count read.
1844 /* no page was available -- either SIGBUS or OOM */
1845 if (new_page
== NOPAGE_SIGBUS
)
1846 return VM_FAULT_SIGBUS
;
1847 if (new_page
== NOPAGE_OOM
)
1848 return VM_FAULT_OOM
;
1851 * Should we do an early C-O-W break?
1853 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1856 if (unlikely(anon_vma_prepare(vma
)))
1858 page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1861 copy_user_highpage(page
, new_page
, address
);
1862 page_cache_release(new_page
);
1867 spin_lock(&mm
->page_table_lock
);
1869 * For a file-backed vma, someone could have truncated or otherwise
1870 * invalidated this page. If unmap_mapping_range got called,
1871 * retry getting the page.
1873 if (mapping
&& unlikely(sequence
!= mapping
->truncate_count
)) {
1874 sequence
= mapping
->truncate_count
;
1875 spin_unlock(&mm
->page_table_lock
);
1876 page_cache_release(new_page
);
1879 page_table
= pte_offset_map(pmd
, address
);
1882 * This silly early PAGE_DIRTY setting removes a race
1883 * due to the bad i386 page protection. But it's valid
1884 * for other architectures too.
1886 * Note that if write_access is true, we either now have
1887 * an exclusive copy of the page, or this is a shared mapping,
1888 * so we can make it writable and dirty to avoid having to
1889 * handle that later.
1891 /* Only go through if we didn't race with anybody else... */
1892 if (pte_none(*page_table
)) {
1893 if (!PageReserved(new_page
))
1894 inc_mm_counter(mm
, rss
);
1896 flush_icache_page(vma
, new_page
);
1897 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1899 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1900 set_pte_at(mm
, address
, page_table
, entry
);
1902 lru_cache_add_active(new_page
);
1903 page_add_anon_rmap(new_page
, vma
, address
);
1905 page_add_file_rmap(new_page
);
1906 pte_unmap(page_table
);
1908 /* One of our sibling threads was faster, back out. */
1909 pte_unmap(page_table
);
1910 page_cache_release(new_page
);
1911 spin_unlock(&mm
->page_table_lock
);
1915 /* no need to invalidate: a not-present page shouldn't be cached */
1916 update_mmu_cache(vma
, address
, entry
);
1917 lazy_mmu_prot_update(entry
);
1918 spin_unlock(&mm
->page_table_lock
);
1922 page_cache_release(new_page
);
1928 * Fault of a previously existing named mapping. Repopulate the pte
1929 * from the encoded file_pte if possible. This enables swappable
1932 static int do_file_page(struct mm_struct
* mm
, struct vm_area_struct
* vma
,
1933 unsigned long address
, int write_access
, pte_t
*pte
, pmd_t
*pmd
)
1935 unsigned long pgoff
;
1938 BUG_ON(!vma
->vm_ops
|| !vma
->vm_ops
->nopage
);
1940 * Fall back to the linear mapping if the fs does not support
1943 if (!vma
->vm_ops
|| !vma
->vm_ops
->populate
||
1944 (write_access
&& !(vma
->vm_flags
& VM_SHARED
))) {
1945 pte_clear(mm
, address
, pte
);
1946 return do_no_page(mm
, vma
, address
, write_access
, pte
, pmd
);
1949 pgoff
= pte_to_pgoff(*pte
);
1952 spin_unlock(&mm
->page_table_lock
);
1954 err
= vma
->vm_ops
->populate(vma
, address
& PAGE_MASK
, PAGE_SIZE
, vma
->vm_page_prot
, pgoff
, 0);
1956 return VM_FAULT_OOM
;
1958 return VM_FAULT_SIGBUS
;
1959 return VM_FAULT_MAJOR
;
1963 * These routines also need to handle stuff like marking pages dirty
1964 * and/or accessed for architectures that don't do it in hardware (most
1965 * RISC architectures). The early dirtying is also good on the i386.
1967 * There is also a hook called "update_mmu_cache()" that architectures
1968 * with external mmu caches can use to update those (ie the Sparc or
1969 * PowerPC hashed page tables that act as extended TLBs).
1971 * Note the "page_table_lock". It is to protect against kswapd removing
1972 * pages from under us. Note that kswapd only ever _removes_ pages, never
1973 * adds them. As such, once we have noticed that the page is not present,
1974 * we can drop the lock early.
1976 * The adding of pages is protected by the MM semaphore (which we hold),
1977 * so we don't need to worry about a page being suddenly been added into
1980 * We enter with the pagetable spinlock held, we are supposed to
1981 * release it when done.
1983 static inline int handle_pte_fault(struct mm_struct
*mm
,
1984 struct vm_area_struct
* vma
, unsigned long address
,
1985 int write_access
, pte_t
*pte
, pmd_t
*pmd
)
1990 if (!pte_present(entry
)) {
1992 * If it truly wasn't present, we know that kswapd
1993 * and the PTE updates will not touch it later. So
1996 if (pte_none(entry
))
1997 return do_no_page(mm
, vma
, address
, write_access
, pte
, pmd
);
1998 if (pte_file(entry
))
1999 return do_file_page(mm
, vma
, address
, write_access
, pte
, pmd
);
2000 return do_swap_page(mm
, vma
, address
, pte
, pmd
, entry
, write_access
);
2004 if (!pte_write(entry
))
2005 return do_wp_page(mm
, vma
, address
, pte
, pmd
, entry
);
2006 entry
= pte_mkdirty(entry
);
2008 entry
= pte_mkyoung(entry
);
2009 ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
);
2010 update_mmu_cache(vma
, address
, entry
);
2011 lazy_mmu_prot_update(entry
);
2013 spin_unlock(&mm
->page_table_lock
);
2014 return VM_FAULT_MINOR
;
2018 * By the time we get here, we already hold the mm semaphore
2020 int __handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
* vma
,
2021 unsigned long address
, int write_access
)
2028 __set_current_state(TASK_RUNNING
);
2030 inc_page_state(pgfault
);
2032 if (is_vm_hugetlb_page(vma
))
2033 return VM_FAULT_SIGBUS
; /* mapping truncation does this. */
2036 * We need the page table lock to synchronize with kswapd
2037 * and the SMP-safe atomic PTE updates.
2039 pgd
= pgd_offset(mm
, address
);
2040 spin_lock(&mm
->page_table_lock
);
2042 pud
= pud_alloc(mm
, pgd
, address
);
2046 pmd
= pmd_alloc(mm
, pud
, address
);
2050 pte
= pte_alloc_map(mm
, pmd
, address
);
2054 return handle_pte_fault(mm
, vma
, address
, write_access
, pte
, pmd
);
2057 spin_unlock(&mm
->page_table_lock
);
2058 return VM_FAULT_OOM
;
2061 #ifndef __PAGETABLE_PUD_FOLDED
2063 * Allocate page upper directory.
2065 * We've already handled the fast-path in-line, and we own the
2068 pud_t fastcall
*__pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2072 spin_unlock(&mm
->page_table_lock
);
2073 new = pud_alloc_one(mm
, address
);
2074 spin_lock(&mm
->page_table_lock
);
2079 * Because we dropped the lock, we should re-check the
2080 * entry, as somebody else could have populated it..
2082 if (pgd_present(*pgd
)) {
2086 pgd_populate(mm
, pgd
, new);
2088 return pud_offset(pgd
, address
);
2090 #endif /* __PAGETABLE_PUD_FOLDED */
2092 #ifndef __PAGETABLE_PMD_FOLDED
2094 * Allocate page middle directory.
2096 * We've already handled the fast-path in-line, and we own the
2099 pmd_t fastcall
*__pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2103 spin_unlock(&mm
->page_table_lock
);
2104 new = pmd_alloc_one(mm
, address
);
2105 spin_lock(&mm
->page_table_lock
);
2110 * Because we dropped the lock, we should re-check the
2111 * entry, as somebody else could have populated it..
2113 #ifndef __ARCH_HAS_4LEVEL_HACK
2114 if (pud_present(*pud
)) {
2118 pud_populate(mm
, pud
, new);
2120 if (pgd_present(*pud
)) {
2124 pgd_populate(mm
, pud
, new);
2125 #endif /* __ARCH_HAS_4LEVEL_HACK */
2128 return pmd_offset(pud
, address
);
2130 #endif /* __PAGETABLE_PMD_FOLDED */
2132 int make_pages_present(unsigned long addr
, unsigned long end
)
2134 int ret
, len
, write
;
2135 struct vm_area_struct
* vma
;
2137 vma
= find_vma(current
->mm
, addr
);
2140 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2143 if (end
> vma
->vm_end
)
2145 len
= (end
+PAGE_SIZE
-1)/PAGE_SIZE
-addr
/PAGE_SIZE
;
2146 ret
= get_user_pages(current
, current
->mm
, addr
,
2147 len
, write
, 0, NULL
, NULL
);
2150 return ret
== len
? 0 : -1;
2154 * Map a vmalloc()-space virtual address to the physical page.
2156 struct page
* vmalloc_to_page(void * vmalloc_addr
)
2158 unsigned long addr
= (unsigned long) vmalloc_addr
;
2159 struct page
*page
= NULL
;
2160 pgd_t
*pgd
= pgd_offset_k(addr
);
2165 if (!pgd_none(*pgd
)) {
2166 pud
= pud_offset(pgd
, addr
);
2167 if (!pud_none(*pud
)) {
2168 pmd
= pmd_offset(pud
, addr
);
2169 if (!pmd_none(*pmd
)) {
2170 ptep
= pte_offset_map(pmd
, addr
);
2172 if (pte_present(pte
))
2173 page
= pte_page(pte
);
2181 EXPORT_SYMBOL(vmalloc_to_page
);
2184 * Map a vmalloc()-space virtual address to the physical page frame number.
2186 unsigned long vmalloc_to_pfn(void * vmalloc_addr
)
2188 return page_to_pfn(vmalloc_to_page(vmalloc_addr
));
2191 EXPORT_SYMBOL(vmalloc_to_pfn
);
2194 * update_mem_hiwater
2195 * - update per process rss and vm high water data
2197 void update_mem_hiwater(struct task_struct
*tsk
)
2200 unsigned long rss
= get_mm_counter(tsk
->mm
, rss
);
2202 if (tsk
->mm
->hiwater_rss
< rss
)
2203 tsk
->mm
->hiwater_rss
= rss
;
2204 if (tsk
->mm
->hiwater_vm
< tsk
->mm
->total_vm
)
2205 tsk
->mm
->hiwater_vm
= tsk
->mm
->total_vm
;
2209 #if !defined(__HAVE_ARCH_GATE_AREA)
2211 #if defined(AT_SYSINFO_EHDR)
2212 struct vm_area_struct gate_vma
;
2214 static int __init
gate_vma_init(void)
2216 gate_vma
.vm_mm
= NULL
;
2217 gate_vma
.vm_start
= FIXADDR_USER_START
;
2218 gate_vma
.vm_end
= FIXADDR_USER_END
;
2219 gate_vma
.vm_page_prot
= PAGE_READONLY
;
2220 gate_vma
.vm_flags
= 0;
2223 __initcall(gate_vma_init
);
2226 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2228 #ifdef AT_SYSINFO_EHDR
2235 int in_gate_area_no_task(unsigned long addr
)
2237 #ifdef AT_SYSINFO_EHDR
2238 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2244 #endif /* __HAVE_ARCH_GATE_AREA */
This page took 0.229014 seconds and 6 git commands to generate.