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
);
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 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
287 spin_unlock(&mm
->page_table_lock
);
288 new = pte_alloc_one(mm
, address
);
289 spin_lock(&mm
->page_table_lock
);
293 if (pmd_present(*pmd
)) /* Another has populated it */
297 inc_page_state(nr_page_table_pages
);
298 pmd_populate(mm
, pmd
, new);
303 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
305 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
309 spin_lock(&init_mm
.page_table_lock
);
310 if (pmd_present(*pmd
)) /* Another has populated it */
311 pte_free_kernel(new);
313 pmd_populate_kernel(&init_mm
, pmd
, new);
314 spin_unlock(&init_mm
.page_table_lock
);
318 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
321 add_mm_counter(mm
, file_rss
, file_rss
);
323 add_mm_counter(mm
, anon_rss
, anon_rss
);
327 * This function is called to print an error when a pte in a
328 * !VM_RESERVED region is found pointing to an invalid pfn (which
331 * The calling function must still handle the error.
333 void print_bad_pte(struct vm_area_struct
*vma
, pte_t pte
, unsigned long vaddr
)
335 printk(KERN_ERR
"Bad pte = %08llx, process = %s, "
336 "vm_flags = %lx, vaddr = %lx\n",
337 (long long)pte_val(pte
),
338 (vma
->vm_mm
== current
->mm
? current
->comm
: "???"),
339 vma
->vm_flags
, vaddr
);
344 * copy one vm_area from one task to the other. Assumes the page tables
345 * already present in the new task to be cleared in the whole range
346 * covered by this vma.
348 * dst->page_table_lock is held on entry and exit,
349 * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
353 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
354 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
355 unsigned long addr
, int *rss
)
357 unsigned long vm_flags
= vma
->vm_flags
;
358 pte_t pte
= *src_pte
;
362 /* pte contains position in swap or file, so copy. */
363 if (unlikely(!pte_present(pte
))) {
364 if (!pte_file(pte
)) {
365 swap_duplicate(pte_to_swp_entry(pte
));
366 /* make sure dst_mm is on swapoff's mmlist. */
367 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
368 spin_lock(&mmlist_lock
);
369 list_add(&dst_mm
->mmlist
, &src_mm
->mmlist
);
370 spin_unlock(&mmlist_lock
);
376 /* If the region is VM_RESERVED, the mapping is not
377 * mapped via rmap - duplicate the pte as is.
379 if (vm_flags
& VM_RESERVED
)
383 /* If the pte points outside of valid memory but
384 * the region is not VM_RESERVED, we have a problem.
386 if (unlikely(!pfn_valid(pfn
))) {
387 print_bad_pte(vma
, pte
, addr
);
388 goto out_set_pte
; /* try to do something sane */
391 page
= pfn_to_page(pfn
);
394 * If it's a COW mapping, write protect it both
395 * in the parent and the child
397 if ((vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
) {
398 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
403 * If it's a shared mapping, mark it clean in
406 if (vm_flags
& VM_SHARED
)
407 pte
= pte_mkclean(pte
);
408 pte
= pte_mkold(pte
);
411 rss
[!!PageAnon(page
)]++;
414 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
417 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
418 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
419 unsigned long addr
, unsigned long end
)
421 pte_t
*src_pte
, *dst_pte
;
427 dst_pte
= pte_alloc_map(dst_mm
, dst_pmd
, addr
);
430 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
432 spin_lock(&src_mm
->page_table_lock
);
435 * We are holding two locks at this point - either of them
436 * could generate latencies in another task on another CPU.
438 if (progress
>= 32) {
440 if (need_resched() ||
441 need_lockbreak(&src_mm
->page_table_lock
) ||
442 need_lockbreak(&dst_mm
->page_table_lock
))
445 if (pte_none(*src_pte
)) {
449 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
451 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
452 spin_unlock(&src_mm
->page_table_lock
);
454 pte_unmap_nested(src_pte
- 1);
455 pte_unmap(dst_pte
- 1);
456 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
457 cond_resched_lock(&dst_mm
->page_table_lock
);
463 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
464 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
465 unsigned long addr
, unsigned long end
)
467 pmd_t
*src_pmd
, *dst_pmd
;
470 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
473 src_pmd
= pmd_offset(src_pud
, addr
);
475 next
= pmd_addr_end(addr
, end
);
476 if (pmd_none_or_clear_bad(src_pmd
))
478 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
481 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
485 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
486 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
487 unsigned long addr
, unsigned long end
)
489 pud_t
*src_pud
, *dst_pud
;
492 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
495 src_pud
= pud_offset(src_pgd
, addr
);
497 next
= pud_addr_end(addr
, end
);
498 if (pud_none_or_clear_bad(src_pud
))
500 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
503 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
507 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
508 struct vm_area_struct
*vma
)
510 pgd_t
*src_pgd
, *dst_pgd
;
512 unsigned long addr
= vma
->vm_start
;
513 unsigned long end
= vma
->vm_end
;
516 * Don't copy ptes where a page fault will fill them correctly.
517 * Fork becomes much lighter when there are big shared or private
518 * readonly mappings. The tradeoff is that copy_page_range is more
519 * efficient than faulting.
521 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_RESERVED
))) {
526 if (is_vm_hugetlb_page(vma
))
527 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
529 dst_pgd
= pgd_offset(dst_mm
, addr
);
530 src_pgd
= pgd_offset(src_mm
, addr
);
532 next
= pgd_addr_end(addr
, end
);
533 if (pgd_none_or_clear_bad(src_pgd
))
535 if (copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
538 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
542 static void zap_pte_range(struct mmu_gather
*tlb
,
543 struct vm_area_struct
*vma
, pmd_t
*pmd
,
544 unsigned long addr
, unsigned long end
,
545 struct zap_details
*details
)
547 struct mm_struct
*mm
= tlb
->mm
;
552 pte
= pte_offset_map(pmd
, addr
);
557 if (pte_present(ptent
)) {
558 struct page
*page
= NULL
;
559 if (!(vma
->vm_flags
& VM_RESERVED
)) {
560 unsigned long pfn
= pte_pfn(ptent
);
561 if (unlikely(!pfn_valid(pfn
)))
562 print_bad_pte(vma
, ptent
, addr
);
564 page
= pfn_to_page(pfn
);
566 if (unlikely(details
) && page
) {
568 * unmap_shared_mapping_pages() wants to
569 * invalidate cache without truncating:
570 * unmap shared but keep private pages.
572 if (details
->check_mapping
&&
573 details
->check_mapping
!= page
->mapping
)
576 * Each page->index must be checked when
577 * invalidating or truncating nonlinear.
579 if (details
->nonlinear_vma
&&
580 (page
->index
< details
->first_index
||
581 page
->index
> details
->last_index
))
584 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
586 tlb_remove_tlb_entry(tlb
, pte
, addr
);
589 if (unlikely(details
) && details
->nonlinear_vma
590 && linear_page_index(details
->nonlinear_vma
,
591 addr
) != page
->index
)
592 set_pte_at(mm
, addr
, pte
,
593 pgoff_to_pte(page
->index
));
597 if (pte_dirty(ptent
))
598 set_page_dirty(page
);
599 if (pte_young(ptent
))
600 mark_page_accessed(page
);
603 page_remove_rmap(page
);
604 tlb_remove_page(tlb
, page
);
608 * If details->check_mapping, we leave swap entries;
609 * if details->nonlinear_vma, we leave file entries.
611 if (unlikely(details
))
613 if (!pte_file(ptent
))
614 free_swap_and_cache(pte_to_swp_entry(ptent
));
615 pte_clear_full(mm
, addr
, pte
, tlb
->fullmm
);
616 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
618 add_mm_rss(mm
, file_rss
, anon_rss
);
622 static inline void zap_pmd_range(struct mmu_gather
*tlb
,
623 struct vm_area_struct
*vma
, pud_t
*pud
,
624 unsigned long addr
, unsigned long end
,
625 struct zap_details
*details
)
630 pmd
= pmd_offset(pud
, addr
);
632 next
= pmd_addr_end(addr
, end
);
633 if (pmd_none_or_clear_bad(pmd
))
635 zap_pte_range(tlb
, vma
, pmd
, addr
, next
, details
);
636 } while (pmd
++, addr
= next
, addr
!= end
);
639 static inline void zap_pud_range(struct mmu_gather
*tlb
,
640 struct vm_area_struct
*vma
, pgd_t
*pgd
,
641 unsigned long addr
, unsigned long end
,
642 struct zap_details
*details
)
647 pud
= pud_offset(pgd
, addr
);
649 next
= pud_addr_end(addr
, end
);
650 if (pud_none_or_clear_bad(pud
))
652 zap_pmd_range(tlb
, vma
, pud
, addr
, next
, details
);
653 } while (pud
++, addr
= next
, addr
!= end
);
656 static void unmap_page_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
657 unsigned long addr
, unsigned long end
,
658 struct zap_details
*details
)
663 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
667 tlb_start_vma(tlb
, vma
);
668 pgd
= pgd_offset(vma
->vm_mm
, addr
);
670 next
= pgd_addr_end(addr
, end
);
671 if (pgd_none_or_clear_bad(pgd
))
673 zap_pud_range(tlb
, vma
, pgd
, addr
, next
, details
);
674 } while (pgd
++, addr
= next
, addr
!= end
);
675 tlb_end_vma(tlb
, vma
);
678 #ifdef CONFIG_PREEMPT
679 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
681 /* No preempt: go for improved straight-line efficiency */
682 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
686 * unmap_vmas - unmap a range of memory covered by a list of vma's
687 * @tlbp: address of the caller's struct mmu_gather
688 * @mm: the controlling mm_struct
689 * @vma: the starting vma
690 * @start_addr: virtual address at which to start unmapping
691 * @end_addr: virtual address at which to end unmapping
692 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
693 * @details: details of nonlinear truncation or shared cache invalidation
695 * Returns the end address of the unmapping (restart addr if interrupted).
697 * Unmap all pages in the vma list. Called under page_table_lock.
699 * We aim to not hold page_table_lock for too long (for scheduling latency
700 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
701 * return the ending mmu_gather to the caller.
703 * Only addresses between `start' and `end' will be unmapped.
705 * The VMA list must be sorted in ascending virtual address order.
707 * unmap_vmas() assumes that the caller will flush the whole unmapped address
708 * range after unmap_vmas() returns. So the only responsibility here is to
709 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
710 * drops the lock and schedules.
712 unsigned long unmap_vmas(struct mmu_gather
**tlbp
, struct mm_struct
*mm
,
713 struct vm_area_struct
*vma
, unsigned long start_addr
,
714 unsigned long end_addr
, unsigned long *nr_accounted
,
715 struct zap_details
*details
)
717 unsigned long zap_bytes
= ZAP_BLOCK_SIZE
;
718 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
719 int tlb_start_valid
= 0;
720 unsigned long start
= start_addr
;
721 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
722 int fullmm
= (*tlbp
)->fullmm
;
724 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
727 start
= max(vma
->vm_start
, start_addr
);
728 if (start
>= vma
->vm_end
)
730 end
= min(vma
->vm_end
, end_addr
);
731 if (end
<= vma
->vm_start
)
734 if (vma
->vm_flags
& VM_ACCOUNT
)
735 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
737 while (start
!= end
) {
740 if (!tlb_start_valid
) {
745 if (is_vm_hugetlb_page(vma
)) {
747 unmap_hugepage_range(vma
, start
, end
);
749 block
= min(zap_bytes
, end
- start
);
750 unmap_page_range(*tlbp
, vma
, start
,
751 start
+ block
, details
);
756 if ((long)zap_bytes
> 0)
759 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
761 if (need_resched() ||
762 need_lockbreak(&mm
->page_table_lock
) ||
763 (i_mmap_lock
&& need_lockbreak(i_mmap_lock
))) {
765 /* must reset count of rss freed */
766 *tlbp
= tlb_gather_mmu(mm
, fullmm
);
769 spin_unlock(&mm
->page_table_lock
);
771 spin_lock(&mm
->page_table_lock
);
774 *tlbp
= tlb_gather_mmu(mm
, fullmm
);
776 zap_bytes
= ZAP_BLOCK_SIZE
;
780 return start
; /* which is now the end (or restart) address */
784 * zap_page_range - remove user pages in a given range
785 * @vma: vm_area_struct holding the applicable pages
786 * @address: starting address of pages to zap
787 * @size: number of bytes to zap
788 * @details: details of nonlinear truncation or shared cache invalidation
790 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
791 unsigned long size
, struct zap_details
*details
)
793 struct mm_struct
*mm
= vma
->vm_mm
;
794 struct mmu_gather
*tlb
;
795 unsigned long end
= address
+ size
;
796 unsigned long nr_accounted
= 0;
798 if (is_vm_hugetlb_page(vma
)) {
799 zap_hugepage_range(vma
, address
, size
);
804 spin_lock(&mm
->page_table_lock
);
805 tlb
= tlb_gather_mmu(mm
, 0);
806 update_hiwater_rss(mm
);
807 end
= unmap_vmas(&tlb
, mm
, vma
, address
, end
, &nr_accounted
, details
);
808 tlb_finish_mmu(tlb
, address
, end
);
809 spin_unlock(&mm
->page_table_lock
);
814 * Do a quick page-table lookup for a single page.
815 * mm->page_table_lock must be held.
817 static struct page
*__follow_page(struct mm_struct
*mm
, unsigned long address
,
818 int read
, int write
, int accessed
)
827 page
= follow_huge_addr(mm
, address
, write
);
831 pgd
= pgd_offset(mm
, address
);
832 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
835 pud
= pud_offset(pgd
, address
);
836 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
839 pmd
= pmd_offset(pud
, address
);
840 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
843 return follow_huge_pmd(mm
, address
, pmd
, write
);
845 ptep
= pte_offset_map(pmd
, address
);
851 if (pte_present(pte
)) {
852 if (write
&& !pte_write(pte
))
854 if (read
&& !pte_read(pte
))
857 if (pfn_valid(pfn
)) {
858 page
= pfn_to_page(pfn
);
860 if (write
&& !pte_dirty(pte
) &&!PageDirty(page
))
861 set_page_dirty(page
);
862 mark_page_accessed(page
);
873 follow_page(struct mm_struct
*mm
, unsigned long address
, int write
)
875 return __follow_page(mm
, address
, 0, write
, 1);
879 * check_user_page_readable() can be called frm niterrupt context by oprofile,
880 * so we need to avoid taking any non-irq-safe locks
882 int check_user_page_readable(struct mm_struct
*mm
, unsigned long address
)
884 return __follow_page(mm
, address
, 1, 0, 0) != NULL
;
886 EXPORT_SYMBOL(check_user_page_readable
);
889 untouched_anonymous_page(struct mm_struct
* mm
, struct vm_area_struct
*vma
,
890 unsigned long address
)
896 /* Check if the vma is for an anonymous mapping. */
897 if (vma
->vm_ops
&& vma
->vm_ops
->nopage
)
900 /* Check if page directory entry exists. */
901 pgd
= pgd_offset(mm
, address
);
902 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
905 pud
= pud_offset(pgd
, address
);
906 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
909 /* Check if page middle directory entry exists. */
910 pmd
= pmd_offset(pud
, address
);
911 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
914 /* There is a pte slot for 'address' in 'mm'. */
918 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
919 unsigned long start
, int len
, int write
, int force
,
920 struct page
**pages
, struct vm_area_struct
**vmas
)
926 * Require read or write permissions.
927 * If 'force' is set, we only require the "MAY" flags.
929 flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
930 flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
934 struct vm_area_struct
* vma
;
936 vma
= find_extend_vma(mm
, start
);
937 if (!vma
&& in_gate_area(tsk
, start
)) {
938 unsigned long pg
= start
& PAGE_MASK
;
939 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
944 if (write
) /* user gate pages are read-only */
945 return i
? : -EFAULT
;
947 pgd
= pgd_offset_k(pg
);
949 pgd
= pgd_offset_gate(mm
, pg
);
950 BUG_ON(pgd_none(*pgd
));
951 pud
= pud_offset(pgd
, pg
);
952 BUG_ON(pud_none(*pud
));
953 pmd
= pmd_offset(pud
, pg
);
955 return i
? : -EFAULT
;
956 pte
= pte_offset_map(pmd
, pg
);
957 if (pte_none(*pte
)) {
959 return i
? : -EFAULT
;
962 pages
[i
] = pte_page(*pte
);
974 if (!vma
|| (vma
->vm_flags
& (VM_IO
| VM_RESERVED
))
975 || !(flags
& vma
->vm_flags
))
976 return i
? : -EFAULT
;
978 if (is_vm_hugetlb_page(vma
)) {
979 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
983 spin_lock(&mm
->page_table_lock
);
985 int write_access
= write
;
988 cond_resched_lock(&mm
->page_table_lock
);
989 while (!(page
= follow_page(mm
, start
, write_access
))) {
993 * Shortcut for anonymous pages. We don't want
994 * to force the creation of pages tables for
995 * insanely big anonymously mapped areas that
996 * nobody touched so far. This is important
997 * for doing a core dump for these mappings.
999 if (!write
&& untouched_anonymous_page(mm
,vma
,start
)) {
1000 page
= ZERO_PAGE(start
);
1003 spin_unlock(&mm
->page_table_lock
);
1004 ret
= __handle_mm_fault(mm
, vma
, start
, write_access
);
1007 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1008 * broken COW when necessary, even if maybe_mkwrite
1009 * decided not to set pte_write. We can thus safely do
1010 * subsequent page lookups as if they were reads.
1012 if (ret
& VM_FAULT_WRITE
)
1015 switch (ret
& ~VM_FAULT_WRITE
) {
1016 case VM_FAULT_MINOR
:
1019 case VM_FAULT_MAJOR
:
1022 case VM_FAULT_SIGBUS
:
1023 return i
? i
: -EFAULT
;
1025 return i
? i
: -ENOMEM
;
1029 spin_lock(&mm
->page_table_lock
);
1033 flush_dcache_page(page
);
1034 page_cache_get(page
);
1041 } while (len
&& start
< vma
->vm_end
);
1042 spin_unlock(&mm
->page_table_lock
);
1046 EXPORT_SYMBOL(get_user_pages
);
1048 static int zeromap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1049 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1053 pte
= pte_alloc_map(mm
, pmd
, addr
);
1057 struct page
*page
= ZERO_PAGE(addr
);
1058 pte_t zero_pte
= pte_wrprotect(mk_pte(page
, prot
));
1059 page_cache_get(page
);
1060 page_add_file_rmap(page
);
1061 inc_mm_counter(mm
, file_rss
);
1062 BUG_ON(!pte_none(*pte
));
1063 set_pte_at(mm
, addr
, pte
, zero_pte
);
1064 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1069 static inline int zeromap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1070 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1075 pmd
= pmd_alloc(mm
, pud
, addr
);
1079 next
= pmd_addr_end(addr
, end
);
1080 if (zeromap_pte_range(mm
, pmd
, addr
, next
, prot
))
1082 } while (pmd
++, addr
= next
, addr
!= end
);
1086 static inline int zeromap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1087 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1092 pud
= pud_alloc(mm
, pgd
, addr
);
1096 next
= pud_addr_end(addr
, end
);
1097 if (zeromap_pmd_range(mm
, pud
, addr
, next
, prot
))
1099 } while (pud
++, addr
= next
, addr
!= end
);
1103 int zeromap_page_range(struct vm_area_struct
*vma
,
1104 unsigned long addr
, unsigned long size
, pgprot_t prot
)
1108 unsigned long end
= addr
+ size
;
1109 struct mm_struct
*mm
= vma
->vm_mm
;
1112 BUG_ON(addr
>= end
);
1113 pgd
= pgd_offset(mm
, addr
);
1114 flush_cache_range(vma
, addr
, end
);
1115 spin_lock(&mm
->page_table_lock
);
1117 next
= pgd_addr_end(addr
, end
);
1118 err
= zeromap_pud_range(mm
, pgd
, addr
, next
, prot
);
1121 } while (pgd
++, addr
= next
, addr
!= end
);
1122 spin_unlock(&mm
->page_table_lock
);
1127 * maps a range of physical memory into the requested pages. the old
1128 * mappings are removed. any references to nonexistent pages results
1129 * in null mappings (currently treated as "copy-on-access")
1131 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1132 unsigned long addr
, unsigned long end
,
1133 unsigned long pfn
, pgprot_t prot
)
1137 pte
= pte_alloc_map(mm
, pmd
, addr
);
1141 BUG_ON(!pte_none(*pte
));
1142 set_pte_at(mm
, addr
, pte
, pfn_pte(pfn
, prot
));
1144 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1149 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1150 unsigned long addr
, unsigned long end
,
1151 unsigned long pfn
, pgprot_t prot
)
1156 pfn
-= addr
>> PAGE_SHIFT
;
1157 pmd
= pmd_alloc(mm
, pud
, addr
);
1161 next
= pmd_addr_end(addr
, end
);
1162 if (remap_pte_range(mm
, pmd
, addr
, next
,
1163 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1165 } while (pmd
++, addr
= next
, addr
!= end
);
1169 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1170 unsigned long addr
, unsigned long end
,
1171 unsigned long pfn
, pgprot_t prot
)
1176 pfn
-= addr
>> PAGE_SHIFT
;
1177 pud
= pud_alloc(mm
, pgd
, addr
);
1181 next
= pud_addr_end(addr
, end
);
1182 if (remap_pmd_range(mm
, pud
, addr
, next
,
1183 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1185 } while (pud
++, addr
= next
, addr
!= end
);
1189 /* Note: this is only safe if the mm semaphore is held when called. */
1190 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1191 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1195 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1196 struct mm_struct
*mm
= vma
->vm_mm
;
1200 * Physically remapped pages are special. Tell the
1201 * rest of the world about it:
1202 * VM_IO tells people not to look at these pages
1203 * (accesses can have side effects).
1204 * VM_RESERVED tells the core MM not to "manage" these pages
1205 * (e.g. refcount, mapcount, try to swap them out).
1207 vma
->vm_flags
|= VM_IO
| VM_RESERVED
;
1209 BUG_ON(addr
>= end
);
1210 pfn
-= addr
>> PAGE_SHIFT
;
1211 pgd
= pgd_offset(mm
, addr
);
1212 flush_cache_range(vma
, addr
, end
);
1213 spin_lock(&mm
->page_table_lock
);
1215 next
= pgd_addr_end(addr
, end
);
1216 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1217 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1220 } while (pgd
++, addr
= next
, addr
!= end
);
1221 spin_unlock(&mm
->page_table_lock
);
1224 EXPORT_SYMBOL(remap_pfn_range
);
1227 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1228 * servicing faults for write access. In the normal case, do always want
1229 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1230 * that do not have writing enabled, when used by access_process_vm.
1232 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1234 if (likely(vma
->vm_flags
& VM_WRITE
))
1235 pte
= pte_mkwrite(pte
);
1240 * This routine handles present pages, when users try to write
1241 * to a shared page. It is done by copying the page to a new address
1242 * and decrementing the shared-page counter for the old page.
1244 * Note that this routine assumes that the protection checks have been
1245 * done by the caller (the low-level page fault routine in most cases).
1246 * Thus we can safely just mark it writable once we've done any necessary
1249 * We also mark the page dirty at this point even though the page will
1250 * change only once the write actually happens. This avoids a few races,
1251 * and potentially makes it more efficient.
1253 * We hold the mm semaphore and the page_table_lock on entry and exit
1254 * with the page_table_lock released.
1256 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1257 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1260 struct page
*old_page
, *new_page
;
1261 unsigned long pfn
= pte_pfn(orig_pte
);
1263 int ret
= VM_FAULT_MINOR
;
1265 BUG_ON(vma
->vm_flags
& VM_RESERVED
);
1267 if (unlikely(!pfn_valid(pfn
))) {
1269 * Page table corrupted: show pte and kill process.
1271 print_bad_pte(vma
, orig_pte
, address
);
1275 old_page
= pfn_to_page(pfn
);
1277 if (PageAnon(old_page
) && !TestSetPageLocked(old_page
)) {
1278 int reuse
= can_share_swap_page(old_page
);
1279 unlock_page(old_page
);
1281 flush_cache_page(vma
, address
, pfn
);
1282 entry
= pte_mkyoung(orig_pte
);
1283 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1284 ptep_set_access_flags(vma
, address
, page_table
, entry
, 1);
1285 update_mmu_cache(vma
, address
, entry
);
1286 lazy_mmu_prot_update(entry
);
1287 ret
|= VM_FAULT_WRITE
;
1293 * Ok, we need to copy. Oh, well..
1295 page_cache_get(old_page
);
1296 pte_unmap(page_table
);
1297 spin_unlock(&mm
->page_table_lock
);
1299 if (unlikely(anon_vma_prepare(vma
)))
1301 if (old_page
== ZERO_PAGE(address
)) {
1302 new_page
= alloc_zeroed_user_highpage(vma
, address
);
1306 new_page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1309 copy_user_highpage(new_page
, old_page
, address
);
1313 * Re-check the pte - we dropped the lock
1315 spin_lock(&mm
->page_table_lock
);
1316 page_table
= pte_offset_map(pmd
, address
);
1317 if (likely(pte_same(*page_table
, orig_pte
))) {
1318 page_remove_rmap(old_page
);
1319 if (!PageAnon(old_page
)) {
1320 inc_mm_counter(mm
, anon_rss
);
1321 dec_mm_counter(mm
, file_rss
);
1323 flush_cache_page(vma
, address
, pfn
);
1324 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1325 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1326 ptep_establish(vma
, address
, page_table
, entry
);
1327 update_mmu_cache(vma
, address
, entry
);
1328 lazy_mmu_prot_update(entry
);
1330 lru_cache_add_active(new_page
);
1331 page_add_anon_rmap(new_page
, vma
, address
);
1333 /* Free the old page.. */
1334 new_page
= old_page
;
1335 ret
|= VM_FAULT_WRITE
;
1337 page_cache_release(new_page
);
1338 page_cache_release(old_page
);
1340 pte_unmap(page_table
);
1341 spin_unlock(&mm
->page_table_lock
);
1344 page_cache_release(old_page
);
1345 return VM_FAULT_OOM
;
1349 * Helper functions for unmap_mapping_range().
1351 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1353 * We have to restart searching the prio_tree whenever we drop the lock,
1354 * since the iterator is only valid while the lock is held, and anyway
1355 * a later vma might be split and reinserted earlier while lock dropped.
1357 * The list of nonlinear vmas could be handled more efficiently, using
1358 * a placeholder, but handle it in the same way until a need is shown.
1359 * It is important to search the prio_tree before nonlinear list: a vma
1360 * may become nonlinear and be shifted from prio_tree to nonlinear list
1361 * while the lock is dropped; but never shifted from list to prio_tree.
1363 * In order to make forward progress despite restarting the search,
1364 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1365 * quickly skip it next time around. Since the prio_tree search only
1366 * shows us those vmas affected by unmapping the range in question, we
1367 * can't efficiently keep all vmas in step with mapping->truncate_count:
1368 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1369 * mapping->truncate_count and vma->vm_truncate_count are protected by
1372 * In order to make forward progress despite repeatedly restarting some
1373 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1374 * and restart from that address when we reach that vma again. It might
1375 * have been split or merged, shrunk or extended, but never shifted: so
1376 * restart_addr remains valid so long as it remains in the vma's range.
1377 * unmap_mapping_range forces truncate_count to leap over page-aligned
1378 * values so we can save vma's restart_addr in its truncate_count field.
1380 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1382 static void reset_vma_truncate_counts(struct address_space
*mapping
)
1384 struct vm_area_struct
*vma
;
1385 struct prio_tree_iter iter
;
1387 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
1388 vma
->vm_truncate_count
= 0;
1389 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
1390 vma
->vm_truncate_count
= 0;
1393 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
1394 unsigned long start_addr
, unsigned long end_addr
,
1395 struct zap_details
*details
)
1397 unsigned long restart_addr
;
1401 restart_addr
= vma
->vm_truncate_count
;
1402 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
1403 start_addr
= restart_addr
;
1404 if (start_addr
>= end_addr
) {
1405 /* Top of vma has been split off since last time */
1406 vma
->vm_truncate_count
= details
->truncate_count
;
1411 restart_addr
= zap_page_range(vma
, start_addr
,
1412 end_addr
- start_addr
, details
);
1415 * We cannot rely on the break test in unmap_vmas:
1416 * on the one hand, we don't want to restart our loop
1417 * just because that broke out for the page_table_lock;
1418 * on the other hand, it does no test when vma is small.
1420 need_break
= need_resched() ||
1421 need_lockbreak(details
->i_mmap_lock
);
1423 if (restart_addr
>= end_addr
) {
1424 /* We have now completed this vma: mark it so */
1425 vma
->vm_truncate_count
= details
->truncate_count
;
1429 /* Note restart_addr in vma's truncate_count field */
1430 vma
->vm_truncate_count
= restart_addr
;
1435 spin_unlock(details
->i_mmap_lock
);
1437 spin_lock(details
->i_mmap_lock
);
1441 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
1442 struct zap_details
*details
)
1444 struct vm_area_struct
*vma
;
1445 struct prio_tree_iter iter
;
1446 pgoff_t vba
, vea
, zba
, zea
;
1449 vma_prio_tree_foreach(vma
, &iter
, root
,
1450 details
->first_index
, details
->last_index
) {
1451 /* Skip quickly over those we have already dealt with */
1452 if (vma
->vm_truncate_count
== details
->truncate_count
)
1455 vba
= vma
->vm_pgoff
;
1456 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
1457 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1458 zba
= details
->first_index
;
1461 zea
= details
->last_index
;
1465 if (unmap_mapping_range_vma(vma
,
1466 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
1467 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
1473 static inline void unmap_mapping_range_list(struct list_head
*head
,
1474 struct zap_details
*details
)
1476 struct vm_area_struct
*vma
;
1479 * In nonlinear VMAs there is no correspondence between virtual address
1480 * offset and file offset. So we must perform an exhaustive search
1481 * across *all* the pages in each nonlinear VMA, not just the pages
1482 * whose virtual address lies outside the file truncation point.
1485 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
1486 /* Skip quickly over those we have already dealt with */
1487 if (vma
->vm_truncate_count
== details
->truncate_count
)
1489 details
->nonlinear_vma
= vma
;
1490 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
1491 vma
->vm_end
, details
) < 0)
1497 * unmap_mapping_range - unmap the portion of all mmaps
1498 * in the specified address_space corresponding to the specified
1499 * page range in the underlying file.
1500 * @mapping: the address space containing mmaps to be unmapped.
1501 * @holebegin: byte in first page to unmap, relative to the start of
1502 * the underlying file. This will be rounded down to a PAGE_SIZE
1503 * boundary. Note that this is different from vmtruncate(), which
1504 * must keep the partial page. In contrast, we must get rid of
1506 * @holelen: size of prospective hole in bytes. This will be rounded
1507 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1509 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1510 * but 0 when invalidating pagecache, don't throw away private data.
1512 void unmap_mapping_range(struct address_space
*mapping
,
1513 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
1515 struct zap_details details
;
1516 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
1517 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1519 /* Check for overflow. */
1520 if (sizeof(holelen
) > sizeof(hlen
)) {
1522 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1523 if (holeend
& ~(long long)ULONG_MAX
)
1524 hlen
= ULONG_MAX
- hba
+ 1;
1527 details
.check_mapping
= even_cows
? NULL
: mapping
;
1528 details
.nonlinear_vma
= NULL
;
1529 details
.first_index
= hba
;
1530 details
.last_index
= hba
+ hlen
- 1;
1531 if (details
.last_index
< details
.first_index
)
1532 details
.last_index
= ULONG_MAX
;
1533 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
1535 spin_lock(&mapping
->i_mmap_lock
);
1537 /* serialize i_size write against truncate_count write */
1539 /* Protect against page faults, and endless unmapping loops */
1540 mapping
->truncate_count
++;
1542 * For archs where spin_lock has inclusive semantics like ia64
1543 * this smp_mb() will prevent to read pagetable contents
1544 * before the truncate_count increment is visible to
1548 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
1549 if (mapping
->truncate_count
== 0)
1550 reset_vma_truncate_counts(mapping
);
1551 mapping
->truncate_count
++;
1553 details
.truncate_count
= mapping
->truncate_count
;
1555 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
1556 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
1557 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
1558 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
1559 spin_unlock(&mapping
->i_mmap_lock
);
1561 EXPORT_SYMBOL(unmap_mapping_range
);
1564 * Handle all mappings that got truncated by a "truncate()"
1567 * NOTE! We have to be ready to update the memory sharing
1568 * between the file and the memory map for a potential last
1569 * incomplete page. Ugly, but necessary.
1571 int vmtruncate(struct inode
* inode
, loff_t offset
)
1573 struct address_space
*mapping
= inode
->i_mapping
;
1574 unsigned long limit
;
1576 if (inode
->i_size
< offset
)
1579 * truncation of in-use swapfiles is disallowed - it would cause
1580 * subsequent swapout to scribble on the now-freed blocks.
1582 if (IS_SWAPFILE(inode
))
1584 i_size_write(inode
, offset
);
1585 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
1586 truncate_inode_pages(mapping
, offset
);
1590 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
1591 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
1593 if (offset
> inode
->i_sb
->s_maxbytes
)
1595 i_size_write(inode
, offset
);
1598 if (inode
->i_op
&& inode
->i_op
->truncate
)
1599 inode
->i_op
->truncate(inode
);
1602 send_sig(SIGXFSZ
, current
, 0);
1609 EXPORT_SYMBOL(vmtruncate
);
1612 * Primitive swap readahead code. We simply read an aligned block of
1613 * (1 << page_cluster) entries in the swap area. This method is chosen
1614 * because it doesn't cost us any seek time. We also make sure to queue
1615 * the 'original' request together with the readahead ones...
1617 * This has been extended to use the NUMA policies from the mm triggering
1620 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1622 void swapin_readahead(swp_entry_t entry
, unsigned long addr
,struct vm_area_struct
*vma
)
1625 struct vm_area_struct
*next_vma
= vma
? vma
->vm_next
: NULL
;
1628 struct page
*new_page
;
1629 unsigned long offset
;
1632 * Get the number of handles we should do readahead io to.
1634 num
= valid_swaphandles(entry
, &offset
);
1635 for (i
= 0; i
< num
; offset
++, i
++) {
1636 /* Ok, do the async read-ahead now */
1637 new_page
= read_swap_cache_async(swp_entry(swp_type(entry
),
1638 offset
), vma
, addr
);
1641 page_cache_release(new_page
);
1644 * Find the next applicable VMA for the NUMA policy.
1650 if (addr
>= vma
->vm_end
) {
1652 next_vma
= vma
? vma
->vm_next
: NULL
;
1654 if (vma
&& addr
< vma
->vm_start
)
1657 if (next_vma
&& addr
>= next_vma
->vm_start
) {
1659 next_vma
= vma
->vm_next
;
1664 lru_add_drain(); /* Push any new pages onto the LRU now */
1668 * We hold the mm semaphore and the page_table_lock on entry and
1669 * should release the pagetable lock on exit..
1671 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1672 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1673 int write_access
, pte_t orig_pte
)
1678 int ret
= VM_FAULT_MINOR
;
1680 pte_unmap(page_table
);
1681 spin_unlock(&mm
->page_table_lock
);
1683 entry
= pte_to_swp_entry(orig_pte
);
1684 page
= lookup_swap_cache(entry
);
1686 swapin_readahead(entry
, address
, vma
);
1687 page
= read_swap_cache_async(entry
, vma
, address
);
1690 * Back out if somebody else faulted in this pte while
1691 * we released the page table lock.
1693 spin_lock(&mm
->page_table_lock
);
1694 page_table
= pte_offset_map(pmd
, address
);
1695 if (likely(pte_same(*page_table
, orig_pte
)))
1700 /* Had to read the page from swap area: Major fault */
1701 ret
= VM_FAULT_MAJOR
;
1702 inc_page_state(pgmajfault
);
1706 mark_page_accessed(page
);
1710 * Back out if somebody else faulted in this pte while we
1711 * released the page table lock.
1713 spin_lock(&mm
->page_table_lock
);
1714 page_table
= pte_offset_map(pmd
, address
);
1715 if (unlikely(!pte_same(*page_table
, orig_pte
)))
1718 if (unlikely(!PageUptodate(page
))) {
1719 ret
= VM_FAULT_SIGBUS
;
1723 /* The page isn't present yet, go ahead with the fault. */
1725 inc_mm_counter(mm
, anon_rss
);
1726 pte
= mk_pte(page
, vma
->vm_page_prot
);
1727 if (write_access
&& can_share_swap_page(page
)) {
1728 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
1732 flush_icache_page(vma
, page
);
1733 set_pte_at(mm
, address
, page_table
, pte
);
1734 page_add_anon_rmap(page
, vma
, address
);
1738 remove_exclusive_swap_page(page
);
1742 if (do_wp_page(mm
, vma
, address
,
1743 page_table
, pmd
, pte
) == VM_FAULT_OOM
)
1748 /* No need to invalidate - it was non-present before */
1749 update_mmu_cache(vma
, address
, pte
);
1750 lazy_mmu_prot_update(pte
);
1752 pte_unmap(page_table
);
1753 spin_unlock(&mm
->page_table_lock
);
1757 pte_unmap(page_table
);
1758 spin_unlock(&mm
->page_table_lock
);
1760 page_cache_release(page
);
1765 * We are called with the MM semaphore and page_table_lock
1766 * spinlock held to protect against concurrent faults in
1767 * multithreaded programs.
1769 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1770 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1773 struct page
*page
= ZERO_PAGE(addr
);
1776 /* Mapping of ZERO_PAGE - vm_page_prot is readonly */
1777 entry
= mk_pte(page
, vma
->vm_page_prot
);
1780 /* Allocate our own private page. */
1781 pte_unmap(page_table
);
1782 spin_unlock(&mm
->page_table_lock
);
1784 if (unlikely(anon_vma_prepare(vma
)))
1786 page
= alloc_zeroed_user_highpage(vma
, address
);
1790 spin_lock(&mm
->page_table_lock
);
1791 page_table
= pte_offset_map(pmd
, address
);
1793 if (!pte_none(*page_table
)) {
1794 page_cache_release(page
);
1797 inc_mm_counter(mm
, anon_rss
);
1798 entry
= mk_pte(page
, vma
->vm_page_prot
);
1799 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1800 lru_cache_add_active(page
);
1801 SetPageReferenced(page
);
1802 page_add_anon_rmap(page
, vma
, address
);
1804 inc_mm_counter(mm
, file_rss
);
1805 page_add_file_rmap(page
);
1806 page_cache_get(page
);
1809 set_pte_at(mm
, address
, page_table
, entry
);
1811 /* No need to invalidate - it was non-present before */
1812 update_mmu_cache(vma
, address
, entry
);
1813 lazy_mmu_prot_update(entry
);
1815 pte_unmap(page_table
);
1816 spin_unlock(&mm
->page_table_lock
);
1817 return VM_FAULT_MINOR
;
1819 return VM_FAULT_OOM
;
1823 * do_no_page() tries to create a new page mapping. It aggressively
1824 * tries to share with existing pages, but makes a separate copy if
1825 * the "write_access" parameter is true in order to avoid the next
1828 * As this is called only for pages that do not currently exist, we
1829 * do not need to flush old virtual caches or the TLB.
1831 * This is called with the MM semaphore held and the page table
1832 * spinlock held. Exit with the spinlock released.
1834 static int do_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1835 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1838 struct page
*new_page
;
1839 struct address_space
*mapping
= NULL
;
1841 unsigned int sequence
= 0;
1842 int ret
= VM_FAULT_MINOR
;
1845 pte_unmap(page_table
);
1846 spin_unlock(&mm
->page_table_lock
);
1849 mapping
= vma
->vm_file
->f_mapping
;
1850 sequence
= mapping
->truncate_count
;
1851 smp_rmb(); /* serializes i_size against truncate_count */
1854 new_page
= vma
->vm_ops
->nopage(vma
, address
& PAGE_MASK
, &ret
);
1856 * No smp_rmb is needed here as long as there's a full
1857 * spin_lock/unlock sequence inside the ->nopage callback
1858 * (for the pagecache lookup) that acts as an implicit
1859 * smp_mb() and prevents the i_size read to happen
1860 * after the next truncate_count read.
1863 /* no page was available -- either SIGBUS or OOM */
1864 if (new_page
== NOPAGE_SIGBUS
)
1865 return VM_FAULT_SIGBUS
;
1866 if (new_page
== NOPAGE_OOM
)
1867 return VM_FAULT_OOM
;
1870 * Should we do an early C-O-W break?
1872 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1875 if (unlikely(anon_vma_prepare(vma
)))
1877 page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1880 copy_user_highpage(page
, new_page
, address
);
1881 page_cache_release(new_page
);
1886 spin_lock(&mm
->page_table_lock
);
1888 * For a file-backed vma, someone could have truncated or otherwise
1889 * invalidated this page. If unmap_mapping_range got called,
1890 * retry getting the page.
1892 if (mapping
&& unlikely(sequence
!= mapping
->truncate_count
)) {
1893 spin_unlock(&mm
->page_table_lock
);
1894 page_cache_release(new_page
);
1896 sequence
= mapping
->truncate_count
;
1900 page_table
= pte_offset_map(pmd
, address
);
1903 * This silly early PAGE_DIRTY setting removes a race
1904 * due to the bad i386 page protection. But it's valid
1905 * for other architectures too.
1907 * Note that if write_access is true, we either now have
1908 * an exclusive copy of the page, or this is a shared mapping,
1909 * so we can make it writable and dirty to avoid having to
1910 * handle that later.
1912 /* Only go through if we didn't race with anybody else... */
1913 if (pte_none(*page_table
)) {
1914 flush_icache_page(vma
, new_page
);
1915 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1917 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1918 set_pte_at(mm
, address
, page_table
, entry
);
1920 inc_mm_counter(mm
, anon_rss
);
1921 lru_cache_add_active(new_page
);
1922 page_add_anon_rmap(new_page
, vma
, address
);
1923 } else if (!(vma
->vm_flags
& VM_RESERVED
)) {
1924 inc_mm_counter(mm
, file_rss
);
1925 page_add_file_rmap(new_page
);
1928 /* One of our sibling threads was faster, back out. */
1929 page_cache_release(new_page
);
1933 /* no need to invalidate: a not-present page shouldn't be cached */
1934 update_mmu_cache(vma
, address
, entry
);
1935 lazy_mmu_prot_update(entry
);
1937 pte_unmap(page_table
);
1938 spin_unlock(&mm
->page_table_lock
);
1941 page_cache_release(new_page
);
1942 return VM_FAULT_OOM
;
1946 * Fault of a previously existing named mapping. Repopulate the pte
1947 * from the encoded file_pte if possible. This enables swappable
1950 static int do_file_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1951 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1952 int write_access
, pte_t orig_pte
)
1957 pte_unmap(page_table
);
1958 spin_unlock(&mm
->page_table_lock
);
1960 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
1962 * Page table corrupted: show pte and kill process.
1964 print_bad_pte(vma
, orig_pte
, address
);
1965 return VM_FAULT_OOM
;
1967 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
1969 pgoff
= pte_to_pgoff(orig_pte
);
1970 err
= vma
->vm_ops
->populate(vma
, address
& PAGE_MASK
, PAGE_SIZE
,
1971 vma
->vm_page_prot
, pgoff
, 0);
1973 return VM_FAULT_OOM
;
1975 return VM_FAULT_SIGBUS
;
1976 return VM_FAULT_MAJOR
;
1980 * These routines also need to handle stuff like marking pages dirty
1981 * and/or accessed for architectures that don't do it in hardware (most
1982 * RISC architectures). The early dirtying is also good on the i386.
1984 * There is also a hook called "update_mmu_cache()" that architectures
1985 * with external mmu caches can use to update those (ie the Sparc or
1986 * PowerPC hashed page tables that act as extended TLBs).
1988 * Note the "page_table_lock". It is to protect against kswapd removing
1989 * pages from under us. Note that kswapd only ever _removes_ pages, never
1990 * adds them. As such, once we have noticed that the page is not present,
1991 * we can drop the lock early.
1993 * The adding of pages is protected by the MM semaphore (which we hold),
1994 * so we don't need to worry about a page being suddenly been added into
1997 * We enter with the pagetable spinlock held, we are supposed to
1998 * release it when done.
2000 static inline int handle_pte_fault(struct mm_struct
*mm
,
2001 struct vm_area_struct
*vma
, unsigned long address
,
2002 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
2007 if (!pte_present(entry
)) {
2008 if (pte_none(entry
)) {
2009 if (!vma
->vm_ops
|| !vma
->vm_ops
->nopage
)
2010 return do_anonymous_page(mm
, vma
, address
,
2011 pte
, pmd
, write_access
);
2012 return do_no_page(mm
, vma
, address
,
2013 pte
, pmd
, write_access
);
2015 if (pte_file(entry
))
2016 return do_file_page(mm
, vma
, address
,
2017 pte
, pmd
, write_access
, entry
);
2018 return do_swap_page(mm
, vma
, address
,
2019 pte
, pmd
, write_access
, entry
);
2023 if (!pte_write(entry
))
2024 return do_wp_page(mm
, vma
, address
, pte
, pmd
, entry
);
2025 entry
= pte_mkdirty(entry
);
2027 entry
= pte_mkyoung(entry
);
2028 ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
);
2029 update_mmu_cache(vma
, address
, entry
);
2030 lazy_mmu_prot_update(entry
);
2032 spin_unlock(&mm
->page_table_lock
);
2033 return VM_FAULT_MINOR
;
2037 * By the time we get here, we already hold the mm semaphore
2039 int __handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2040 unsigned long address
, int write_access
)
2047 __set_current_state(TASK_RUNNING
);
2049 inc_page_state(pgfault
);
2051 if (unlikely(is_vm_hugetlb_page(vma
)))
2052 return hugetlb_fault(mm
, vma
, address
, write_access
);
2055 * We need the page table lock to synchronize with kswapd
2056 * and the SMP-safe atomic PTE updates.
2058 pgd
= pgd_offset(mm
, address
);
2059 spin_lock(&mm
->page_table_lock
);
2061 pud
= pud_alloc(mm
, pgd
, address
);
2065 pmd
= pmd_alloc(mm
, pud
, address
);
2069 pte
= pte_alloc_map(mm
, pmd
, address
);
2073 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2076 spin_unlock(&mm
->page_table_lock
);
2077 return VM_FAULT_OOM
;
2080 #ifndef __PAGETABLE_PUD_FOLDED
2082 * Allocate page upper directory.
2083 * We've already handled the fast-path in-line.
2085 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2089 if (mm
!= &init_mm
) /* Temporary bridging hack */
2090 spin_unlock(&mm
->page_table_lock
);
2091 new = pud_alloc_one(mm
, address
);
2093 if (mm
!= &init_mm
) /* Temporary bridging hack */
2094 spin_lock(&mm
->page_table_lock
);
2098 spin_lock(&mm
->page_table_lock
);
2099 if (pgd_present(*pgd
)) /* Another has populated it */
2102 pgd_populate(mm
, pgd
, new);
2103 if (mm
== &init_mm
) /* Temporary bridging hack */
2104 spin_unlock(&mm
->page_table_lock
);
2107 #endif /* __PAGETABLE_PUD_FOLDED */
2109 #ifndef __PAGETABLE_PMD_FOLDED
2111 * Allocate page middle directory.
2112 * We've already handled the fast-path in-line.
2114 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2118 if (mm
!= &init_mm
) /* Temporary bridging hack */
2119 spin_unlock(&mm
->page_table_lock
);
2120 new = pmd_alloc_one(mm
, address
);
2122 if (mm
!= &init_mm
) /* Temporary bridging hack */
2123 spin_lock(&mm
->page_table_lock
);
2127 spin_lock(&mm
->page_table_lock
);
2128 #ifndef __ARCH_HAS_4LEVEL_HACK
2129 if (pud_present(*pud
)) /* Another has populated it */
2132 pud_populate(mm
, pud
, new);
2134 if (pgd_present(*pud
)) /* Another has populated it */
2137 pgd_populate(mm
, pud
, new);
2138 #endif /* __ARCH_HAS_4LEVEL_HACK */
2139 if (mm
== &init_mm
) /* Temporary bridging hack */
2140 spin_unlock(&mm
->page_table_lock
);
2143 #endif /* __PAGETABLE_PMD_FOLDED */
2145 int make_pages_present(unsigned long addr
, unsigned long end
)
2147 int ret
, len
, write
;
2148 struct vm_area_struct
* vma
;
2150 vma
= find_vma(current
->mm
, addr
);
2153 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2156 if (end
> vma
->vm_end
)
2158 len
= (end
+PAGE_SIZE
-1)/PAGE_SIZE
-addr
/PAGE_SIZE
;
2159 ret
= get_user_pages(current
, current
->mm
, addr
,
2160 len
, write
, 0, NULL
, NULL
);
2163 return ret
== len
? 0 : -1;
2167 * Map a vmalloc()-space virtual address to the physical page.
2169 struct page
* vmalloc_to_page(void * vmalloc_addr
)
2171 unsigned long addr
= (unsigned long) vmalloc_addr
;
2172 struct page
*page
= NULL
;
2173 pgd_t
*pgd
= pgd_offset_k(addr
);
2178 if (!pgd_none(*pgd
)) {
2179 pud
= pud_offset(pgd
, addr
);
2180 if (!pud_none(*pud
)) {
2181 pmd
= pmd_offset(pud
, addr
);
2182 if (!pmd_none(*pmd
)) {
2183 ptep
= pte_offset_map(pmd
, addr
);
2185 if (pte_present(pte
))
2186 page
= pte_page(pte
);
2194 EXPORT_SYMBOL(vmalloc_to_page
);
2197 * Map a vmalloc()-space virtual address to the physical page frame number.
2199 unsigned long vmalloc_to_pfn(void * vmalloc_addr
)
2201 return page_to_pfn(vmalloc_to_page(vmalloc_addr
));
2204 EXPORT_SYMBOL(vmalloc_to_pfn
);
2206 #if !defined(__HAVE_ARCH_GATE_AREA)
2208 #if defined(AT_SYSINFO_EHDR)
2209 static struct vm_area_struct gate_vma
;
2211 static int __init
gate_vma_init(void)
2213 gate_vma
.vm_mm
= NULL
;
2214 gate_vma
.vm_start
= FIXADDR_USER_START
;
2215 gate_vma
.vm_end
= FIXADDR_USER_END
;
2216 gate_vma
.vm_page_prot
= PAGE_READONLY
;
2217 gate_vma
.vm_flags
= VM_RESERVED
;
2220 __initcall(gate_vma_init
);
2223 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2225 #ifdef AT_SYSINFO_EHDR
2232 int in_gate_area_no_task(unsigned long addr
)
2234 #ifdef AT_SYSINFO_EHDR
2235 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2241 #endif /* __HAVE_ARCH_GATE_AREA */
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