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_lock_deinit(page
);
118 pte_free_tlb(tlb
, page
);
119 dec_page_state(nr_page_table_pages
);
123 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
124 unsigned long addr
, unsigned long end
,
125 unsigned long floor
, unsigned long ceiling
)
132 pmd
= pmd_offset(pud
, addr
);
134 next
= pmd_addr_end(addr
, end
);
135 if (pmd_none_or_clear_bad(pmd
))
137 free_pte_range(tlb
, pmd
);
138 } while (pmd
++, addr
= next
, addr
!= end
);
148 if (end
- 1 > ceiling
- 1)
151 pmd
= pmd_offset(pud
, start
);
153 pmd_free_tlb(tlb
, pmd
);
156 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
157 unsigned long addr
, unsigned long end
,
158 unsigned long floor
, unsigned long ceiling
)
165 pud
= pud_offset(pgd
, addr
);
167 next
= pud_addr_end(addr
, end
);
168 if (pud_none_or_clear_bad(pud
))
170 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
171 } while (pud
++, addr
= next
, addr
!= end
);
177 ceiling
&= PGDIR_MASK
;
181 if (end
- 1 > ceiling
- 1)
184 pud
= pud_offset(pgd
, start
);
186 pud_free_tlb(tlb
, pud
);
190 * This function frees user-level page tables of a process.
192 * Must be called with pagetable lock held.
194 void free_pgd_range(struct mmu_gather
**tlb
,
195 unsigned long addr
, unsigned long end
,
196 unsigned long floor
, unsigned long ceiling
)
203 * The next few lines have given us lots of grief...
205 * Why are we testing PMD* at this top level? Because often
206 * there will be no work to do at all, and we'd prefer not to
207 * go all the way down to the bottom just to discover that.
209 * Why all these "- 1"s? Because 0 represents both the bottom
210 * of the address space and the top of it (using -1 for the
211 * top wouldn't help much: the masks would do the wrong thing).
212 * The rule is that addr 0 and floor 0 refer to the bottom of
213 * the address space, but end 0 and ceiling 0 refer to the top
214 * Comparisons need to use "end - 1" and "ceiling - 1" (though
215 * that end 0 case should be mythical).
217 * Wherever addr is brought up or ceiling brought down, we must
218 * be careful to reject "the opposite 0" before it confuses the
219 * subsequent tests. But what about where end is brought down
220 * by PMD_SIZE below? no, end can't go down to 0 there.
222 * Whereas we round start (addr) and ceiling down, by different
223 * masks at different levels, in order to test whether a table
224 * now has no other vmas using it, so can be freed, we don't
225 * bother to round floor or end up - the tests don't need that.
239 if (end
- 1 > ceiling
- 1)
245 pgd
= pgd_offset((*tlb
)->mm
, addr
);
247 next
= pgd_addr_end(addr
, end
);
248 if (pgd_none_or_clear_bad(pgd
))
250 free_pud_range(*tlb
, pgd
, addr
, next
, floor
, ceiling
);
251 } while (pgd
++, addr
= next
, addr
!= end
);
254 flush_tlb_pgtables((*tlb
)->mm
, start
, end
);
257 void free_pgtables(struct mmu_gather
**tlb
, struct vm_area_struct
*vma
,
258 unsigned long floor
, unsigned long ceiling
)
261 struct vm_area_struct
*next
= vma
->vm_next
;
262 unsigned long addr
= vma
->vm_start
;
265 * Hide vma from rmap and vmtruncate before freeing pgtables
267 anon_vma_unlink(vma
);
268 unlink_file_vma(vma
);
270 if (is_hugepage_only_range(vma
->vm_mm
, addr
, HPAGE_SIZE
)) {
271 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
272 floor
, next
? next
->vm_start
: ceiling
);
275 * Optimization: gather nearby vmas into one call down
277 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
278 && !is_hugepage_only_range(vma
->vm_mm
, next
->vm_start
,
282 anon_vma_unlink(vma
);
283 unlink_file_vma(vma
);
285 free_pgd_range(tlb
, addr
, vma
->vm_end
,
286 floor
, next
? next
->vm_start
: ceiling
);
292 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
294 struct page
*new = pte_alloc_one(mm
, address
);
299 spin_lock(&mm
->page_table_lock
);
300 if (pmd_present(*pmd
)) { /* Another has populated it */
301 pte_lock_deinit(new);
305 inc_page_state(nr_page_table_pages
);
306 pmd_populate(mm
, pmd
, new);
308 spin_unlock(&mm
->page_table_lock
);
312 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
314 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
318 spin_lock(&init_mm
.page_table_lock
);
319 if (pmd_present(*pmd
)) /* Another has populated it */
320 pte_free_kernel(new);
322 pmd_populate_kernel(&init_mm
, pmd
, new);
323 spin_unlock(&init_mm
.page_table_lock
);
327 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
330 add_mm_counter(mm
, file_rss
, file_rss
);
332 add_mm_counter(mm
, anon_rss
, anon_rss
);
336 * This function is called to print an error when a pte in a
337 * !VM_RESERVED region is found pointing to an invalid pfn (which
340 * The calling function must still handle the error.
342 void print_bad_pte(struct vm_area_struct
*vma
, pte_t pte
, unsigned long vaddr
)
344 printk(KERN_ERR
"Bad pte = %08llx, process = %s, "
345 "vm_flags = %lx, vaddr = %lx\n",
346 (long long)pte_val(pte
),
347 (vma
->vm_mm
== current
->mm
? current
->comm
: "???"),
348 vma
->vm_flags
, vaddr
);
353 * copy one vm_area from one task to the other. Assumes the page tables
354 * already present in the new task to be cleared in the whole range
355 * covered by this vma.
359 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
360 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
361 unsigned long addr
, int *rss
)
363 unsigned long vm_flags
= vma
->vm_flags
;
364 pte_t pte
= *src_pte
;
368 /* pte contains position in swap or file, so copy. */
369 if (unlikely(!pte_present(pte
))) {
370 if (!pte_file(pte
)) {
371 swap_duplicate(pte_to_swp_entry(pte
));
372 /* make sure dst_mm is on swapoff's mmlist. */
373 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
374 spin_lock(&mmlist_lock
);
375 list_add(&dst_mm
->mmlist
, &src_mm
->mmlist
);
376 spin_unlock(&mmlist_lock
);
382 /* If the region is VM_RESERVED, the mapping is not
383 * mapped via rmap - duplicate the pte as is.
385 if (vm_flags
& VM_RESERVED
)
389 /* If the pte points outside of valid memory but
390 * the region is not VM_RESERVED, we have a problem.
392 if (unlikely(!pfn_valid(pfn
))) {
393 print_bad_pte(vma
, pte
, addr
);
394 goto out_set_pte
; /* try to do something sane */
397 page
= pfn_to_page(pfn
);
400 * If it's a COW mapping, write protect it both
401 * in the parent and the child
403 if ((vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
) {
404 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
409 * If it's a shared mapping, mark it clean in
412 if (vm_flags
& VM_SHARED
)
413 pte
= pte_mkclean(pte
);
414 pte
= pte_mkold(pte
);
417 rss
[!!PageAnon(page
)]++;
420 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
423 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
424 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
425 unsigned long addr
, unsigned long end
)
427 pte_t
*src_pte
, *dst_pte
;
428 spinlock_t
*src_ptl
, *dst_ptl
;
434 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
437 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
438 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
443 * We are holding two locks at this point - either of them
444 * could generate latencies in another task on another CPU.
446 if (progress
>= 32) {
448 if (need_resched() ||
449 need_lockbreak(src_ptl
) ||
450 need_lockbreak(dst_ptl
))
453 if (pte_none(*src_pte
)) {
457 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
459 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
461 spin_unlock(src_ptl
);
462 pte_unmap_nested(src_pte
- 1);
463 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
464 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
471 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
472 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
473 unsigned long addr
, unsigned long end
)
475 pmd_t
*src_pmd
, *dst_pmd
;
478 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
481 src_pmd
= pmd_offset(src_pud
, addr
);
483 next
= pmd_addr_end(addr
, end
);
484 if (pmd_none_or_clear_bad(src_pmd
))
486 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
489 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
493 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
494 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
495 unsigned long addr
, unsigned long end
)
497 pud_t
*src_pud
, *dst_pud
;
500 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
503 src_pud
= pud_offset(src_pgd
, addr
);
505 next
= pud_addr_end(addr
, end
);
506 if (pud_none_or_clear_bad(src_pud
))
508 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
511 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
515 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
516 struct vm_area_struct
*vma
)
518 pgd_t
*src_pgd
, *dst_pgd
;
520 unsigned long addr
= vma
->vm_start
;
521 unsigned long end
= vma
->vm_end
;
524 * Don't copy ptes where a page fault will fill them correctly.
525 * Fork becomes much lighter when there are big shared or private
526 * readonly mappings. The tradeoff is that copy_page_range is more
527 * efficient than faulting.
529 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_RESERVED
))) {
534 if (is_vm_hugetlb_page(vma
))
535 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
537 dst_pgd
= pgd_offset(dst_mm
, addr
);
538 src_pgd
= pgd_offset(src_mm
, addr
);
540 next
= pgd_addr_end(addr
, end
);
541 if (pgd_none_or_clear_bad(src_pgd
))
543 if (copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
546 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
550 static void zap_pte_range(struct mmu_gather
*tlb
,
551 struct vm_area_struct
*vma
, pmd_t
*pmd
,
552 unsigned long addr
, unsigned long end
,
553 struct zap_details
*details
)
555 struct mm_struct
*mm
= tlb
->mm
;
561 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
566 if (pte_present(ptent
)) {
567 struct page
*page
= NULL
;
568 if (!(vma
->vm_flags
& VM_RESERVED
)) {
569 unsigned long pfn
= pte_pfn(ptent
);
570 if (unlikely(!pfn_valid(pfn
)))
571 print_bad_pte(vma
, ptent
, addr
);
573 page
= pfn_to_page(pfn
);
575 if (unlikely(details
) && page
) {
577 * unmap_shared_mapping_pages() wants to
578 * invalidate cache without truncating:
579 * unmap shared but keep private pages.
581 if (details
->check_mapping
&&
582 details
->check_mapping
!= page
->mapping
)
585 * Each page->index must be checked when
586 * invalidating or truncating nonlinear.
588 if (details
->nonlinear_vma
&&
589 (page
->index
< details
->first_index
||
590 page
->index
> details
->last_index
))
593 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
595 tlb_remove_tlb_entry(tlb
, pte
, addr
);
598 if (unlikely(details
) && details
->nonlinear_vma
599 && linear_page_index(details
->nonlinear_vma
,
600 addr
) != page
->index
)
601 set_pte_at(mm
, addr
, pte
,
602 pgoff_to_pte(page
->index
));
606 if (pte_dirty(ptent
))
607 set_page_dirty(page
);
608 if (pte_young(ptent
))
609 mark_page_accessed(page
);
612 page_remove_rmap(page
);
613 tlb_remove_page(tlb
, page
);
617 * If details->check_mapping, we leave swap entries;
618 * if details->nonlinear_vma, we leave file entries.
620 if (unlikely(details
))
622 if (!pte_file(ptent
))
623 free_swap_and_cache(pte_to_swp_entry(ptent
));
624 pte_clear_full(mm
, addr
, pte
, tlb
->fullmm
);
625 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
627 add_mm_rss(mm
, file_rss
, anon_rss
);
628 pte_unmap_unlock(pte
- 1, ptl
);
631 static inline void zap_pmd_range(struct mmu_gather
*tlb
,
632 struct vm_area_struct
*vma
, pud_t
*pud
,
633 unsigned long addr
, unsigned long end
,
634 struct zap_details
*details
)
639 pmd
= pmd_offset(pud
, addr
);
641 next
= pmd_addr_end(addr
, end
);
642 if (pmd_none_or_clear_bad(pmd
))
644 zap_pte_range(tlb
, vma
, pmd
, addr
, next
, details
);
645 } while (pmd
++, addr
= next
, addr
!= end
);
648 static inline void zap_pud_range(struct mmu_gather
*tlb
,
649 struct vm_area_struct
*vma
, pgd_t
*pgd
,
650 unsigned long addr
, unsigned long end
,
651 struct zap_details
*details
)
656 pud
= pud_offset(pgd
, addr
);
658 next
= pud_addr_end(addr
, end
);
659 if (pud_none_or_clear_bad(pud
))
661 zap_pmd_range(tlb
, vma
, pud
, addr
, next
, details
);
662 } while (pud
++, addr
= next
, addr
!= end
);
665 static void unmap_page_range(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
666 unsigned long addr
, unsigned long end
,
667 struct zap_details
*details
)
672 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
676 tlb_start_vma(tlb
, vma
);
677 pgd
= pgd_offset(vma
->vm_mm
, addr
);
679 next
= pgd_addr_end(addr
, end
);
680 if (pgd_none_or_clear_bad(pgd
))
682 zap_pud_range(tlb
, vma
, pgd
, addr
, next
, details
);
683 } while (pgd
++, addr
= next
, addr
!= end
);
684 tlb_end_vma(tlb
, vma
);
687 #ifdef CONFIG_PREEMPT
688 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
690 /* No preempt: go for improved straight-line efficiency */
691 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
695 * unmap_vmas - unmap a range of memory covered by a list of vma's
696 * @tlbp: address of the caller's struct mmu_gather
697 * @vma: the starting vma
698 * @start_addr: virtual address at which to start unmapping
699 * @end_addr: virtual address at which to end unmapping
700 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
701 * @details: details of nonlinear truncation or shared cache invalidation
703 * Returns the end address of the unmapping (restart addr if interrupted).
705 * Unmap all pages in the vma list.
707 * We aim to not hold locks for too long (for scheduling latency reasons).
708 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
709 * return the ending mmu_gather to the caller.
711 * Only addresses between `start' and `end' will be unmapped.
713 * The VMA list must be sorted in ascending virtual address order.
715 * unmap_vmas() assumes that the caller will flush the whole unmapped address
716 * range after unmap_vmas() returns. So the only responsibility here is to
717 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
718 * drops the lock and schedules.
720 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
721 struct vm_area_struct
*vma
, unsigned long start_addr
,
722 unsigned long end_addr
, unsigned long *nr_accounted
,
723 struct zap_details
*details
)
725 unsigned long zap_bytes
= ZAP_BLOCK_SIZE
;
726 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
727 int tlb_start_valid
= 0;
728 unsigned long start
= start_addr
;
729 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
730 int fullmm
= (*tlbp
)->fullmm
;
732 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
735 start
= max(vma
->vm_start
, start_addr
);
736 if (start
>= vma
->vm_end
)
738 end
= min(vma
->vm_end
, end_addr
);
739 if (end
<= vma
->vm_start
)
742 if (vma
->vm_flags
& VM_ACCOUNT
)
743 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
745 while (start
!= end
) {
748 if (!tlb_start_valid
) {
753 if (is_vm_hugetlb_page(vma
)) {
755 unmap_hugepage_range(vma
, start
, end
);
757 block
= min(zap_bytes
, end
- start
);
758 unmap_page_range(*tlbp
, vma
, start
,
759 start
+ block
, details
);
764 if ((long)zap_bytes
> 0)
767 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
769 if (need_resched() ||
770 (i_mmap_lock
&& need_lockbreak(i_mmap_lock
))) {
778 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
780 zap_bytes
= ZAP_BLOCK_SIZE
;
784 return start
; /* which is now the end (or restart) address */
788 * zap_page_range - remove user pages in a given range
789 * @vma: vm_area_struct holding the applicable pages
790 * @address: starting address of pages to zap
791 * @size: number of bytes to zap
792 * @details: details of nonlinear truncation or shared cache invalidation
794 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
795 unsigned long size
, struct zap_details
*details
)
797 struct mm_struct
*mm
= vma
->vm_mm
;
798 struct mmu_gather
*tlb
;
799 unsigned long end
= address
+ size
;
800 unsigned long nr_accounted
= 0;
803 tlb
= tlb_gather_mmu(mm
, 0);
804 update_hiwater_rss(mm
);
805 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
807 tlb_finish_mmu(tlb
, address
, end
);
812 * Do a quick page-table lookup for a single page.
814 struct page
*follow_page(struct mm_struct
*mm
, unsigned long address
,
825 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
827 BUG_ON(flags
& FOLL_GET
);
832 pgd
= pgd_offset(mm
, address
);
833 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
836 pud
= pud_offset(pgd
, address
);
837 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
840 pmd
= pmd_offset(pud
, address
);
841 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
844 if (pmd_huge(*pmd
)) {
845 BUG_ON(flags
& FOLL_GET
);
846 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
850 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
855 if (!pte_present(pte
))
857 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
863 page
= pfn_to_page(pfn
);
864 if (flags
& FOLL_GET
)
866 if (flags
& FOLL_TOUCH
) {
867 if ((flags
& FOLL_WRITE
) &&
868 !pte_dirty(pte
) && !PageDirty(page
))
869 set_page_dirty(page
);
870 mark_page_accessed(page
);
873 pte_unmap_unlock(ptep
, ptl
);
879 * When core dumping an enormous anonymous area that nobody
880 * has touched so far, we don't want to allocate page tables.
882 if (flags
& FOLL_ANON
) {
883 page
= ZERO_PAGE(address
);
884 if (flags
& FOLL_GET
)
886 BUG_ON(flags
& FOLL_WRITE
);
891 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
892 unsigned long start
, int len
, int write
, int force
,
893 struct page
**pages
, struct vm_area_struct
**vmas
)
896 unsigned int vm_flags
;
899 * Require read or write permissions.
900 * If 'force' is set, we only require the "MAY" flags.
902 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
903 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
907 struct vm_area_struct
*vma
;
908 unsigned int foll_flags
;
910 vma
= find_extend_vma(mm
, start
);
911 if (!vma
&& in_gate_area(tsk
, start
)) {
912 unsigned long pg
= start
& PAGE_MASK
;
913 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
918 if (write
) /* user gate pages are read-only */
919 return i
? : -EFAULT
;
921 pgd
= pgd_offset_k(pg
);
923 pgd
= pgd_offset_gate(mm
, pg
);
924 BUG_ON(pgd_none(*pgd
));
925 pud
= pud_offset(pgd
, pg
);
926 BUG_ON(pud_none(*pud
));
927 pmd
= pmd_offset(pud
, pg
);
929 return i
? : -EFAULT
;
930 pte
= pte_offset_map(pmd
, pg
);
931 if (pte_none(*pte
)) {
933 return i
? : -EFAULT
;
936 pages
[i
] = pte_page(*pte
);
948 if (!vma
|| (vma
->vm_flags
& (VM_IO
| VM_RESERVED
))
949 || !(vm_flags
& vma
->vm_flags
))
950 return i
? : -EFAULT
;
952 if (is_vm_hugetlb_page(vma
)) {
953 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
958 foll_flags
= FOLL_TOUCH
;
960 foll_flags
|= FOLL_GET
;
961 if (!write
&& !(vma
->vm_flags
& VM_LOCKED
) &&
962 (!vma
->vm_ops
|| !vma
->vm_ops
->nopage
))
963 foll_flags
|= FOLL_ANON
;
969 foll_flags
|= FOLL_WRITE
;
972 while (!(page
= follow_page(mm
, start
, foll_flags
))) {
974 ret
= __handle_mm_fault(mm
, vma
, start
,
975 foll_flags
& FOLL_WRITE
);
977 * The VM_FAULT_WRITE bit tells us that do_wp_page has
978 * broken COW when necessary, even if maybe_mkwrite
979 * decided not to set pte_write. We can thus safely do
980 * subsequent page lookups as if they were reads.
982 if (ret
& VM_FAULT_WRITE
)
983 foll_flags
&= ~FOLL_WRITE
;
985 switch (ret
& ~VM_FAULT_WRITE
) {
992 case VM_FAULT_SIGBUS
:
993 return i
? i
: -EFAULT
;
995 return i
? i
: -ENOMEM
;
1002 flush_dcache_page(page
);
1009 } while (len
&& start
< vma
->vm_end
);
1013 EXPORT_SYMBOL(get_user_pages
);
1015 static int zeromap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1016 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1021 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1025 struct page
*page
= ZERO_PAGE(addr
);
1026 pte_t zero_pte
= pte_wrprotect(mk_pte(page
, prot
));
1027 page_cache_get(page
);
1028 page_add_file_rmap(page
);
1029 inc_mm_counter(mm
, file_rss
);
1030 BUG_ON(!pte_none(*pte
));
1031 set_pte_at(mm
, addr
, pte
, zero_pte
);
1032 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1033 pte_unmap_unlock(pte
- 1, ptl
);
1037 static inline int zeromap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1038 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1043 pmd
= pmd_alloc(mm
, pud
, addr
);
1047 next
= pmd_addr_end(addr
, end
);
1048 if (zeromap_pte_range(mm
, pmd
, addr
, next
, prot
))
1050 } while (pmd
++, addr
= next
, addr
!= end
);
1054 static inline int zeromap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1055 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1060 pud
= pud_alloc(mm
, pgd
, addr
);
1064 next
= pud_addr_end(addr
, end
);
1065 if (zeromap_pmd_range(mm
, pud
, addr
, next
, prot
))
1067 } while (pud
++, addr
= next
, addr
!= end
);
1071 int zeromap_page_range(struct vm_area_struct
*vma
,
1072 unsigned long addr
, unsigned long size
, pgprot_t prot
)
1076 unsigned long end
= addr
+ size
;
1077 struct mm_struct
*mm
= vma
->vm_mm
;
1080 BUG_ON(addr
>= end
);
1081 pgd
= pgd_offset(mm
, addr
);
1082 flush_cache_range(vma
, addr
, end
);
1084 next
= pgd_addr_end(addr
, end
);
1085 err
= zeromap_pud_range(mm
, pgd
, addr
, next
, prot
);
1088 } while (pgd
++, addr
= next
, addr
!= end
);
1093 * maps a range of physical memory into the requested pages. the old
1094 * mappings are removed. any references to nonexistent pages results
1095 * in null mappings (currently treated as "copy-on-access")
1097 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1098 unsigned long addr
, unsigned long end
,
1099 unsigned long pfn
, pgprot_t prot
)
1104 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1108 BUG_ON(!pte_none(*pte
));
1109 set_pte_at(mm
, addr
, pte
, pfn_pte(pfn
, prot
));
1111 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1112 pte_unmap_unlock(pte
- 1, ptl
);
1116 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1117 unsigned long addr
, unsigned long end
,
1118 unsigned long pfn
, pgprot_t prot
)
1123 pfn
-= addr
>> PAGE_SHIFT
;
1124 pmd
= pmd_alloc(mm
, pud
, addr
);
1128 next
= pmd_addr_end(addr
, end
);
1129 if (remap_pte_range(mm
, pmd
, addr
, next
,
1130 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1132 } while (pmd
++, addr
= next
, addr
!= end
);
1136 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1137 unsigned long addr
, unsigned long end
,
1138 unsigned long pfn
, pgprot_t prot
)
1143 pfn
-= addr
>> PAGE_SHIFT
;
1144 pud
= pud_alloc(mm
, pgd
, addr
);
1148 next
= pud_addr_end(addr
, end
);
1149 if (remap_pmd_range(mm
, pud
, addr
, next
,
1150 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1152 } while (pud
++, addr
= next
, addr
!= end
);
1156 /* Note: this is only safe if the mm semaphore is held when called. */
1157 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1158 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1162 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1163 struct mm_struct
*mm
= vma
->vm_mm
;
1167 * Physically remapped pages are special. Tell the
1168 * rest of the world about it:
1169 * VM_IO tells people not to look at these pages
1170 * (accesses can have side effects).
1171 * VM_RESERVED tells the core MM not to "manage" these pages
1172 * (e.g. refcount, mapcount, try to swap them out).
1174 vma
->vm_flags
|= VM_IO
| VM_RESERVED
;
1176 BUG_ON(addr
>= end
);
1177 pfn
-= addr
>> PAGE_SHIFT
;
1178 pgd
= pgd_offset(mm
, addr
);
1179 flush_cache_range(vma
, addr
, end
);
1181 next
= pgd_addr_end(addr
, end
);
1182 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1183 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1186 } while (pgd
++, addr
= next
, addr
!= end
);
1189 EXPORT_SYMBOL(remap_pfn_range
);
1192 * handle_pte_fault chooses page fault handler according to an entry
1193 * which was read non-atomically. Before making any commitment, on
1194 * those architectures or configurations (e.g. i386 with PAE) which
1195 * might give a mix of unmatched parts, do_swap_page and do_file_page
1196 * must check under lock before unmapping the pte and proceeding
1197 * (but do_wp_page is only called after already making such a check;
1198 * and do_anonymous_page and do_no_page can safely check later on).
1200 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1201 pte_t
*page_table
, pte_t orig_pte
)
1204 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1205 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1206 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1208 same
= pte_same(*page_table
, orig_pte
);
1212 pte_unmap(page_table
);
1217 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1218 * servicing faults for write access. In the normal case, do always want
1219 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1220 * that do not have writing enabled, when used by access_process_vm.
1222 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1224 if (likely(vma
->vm_flags
& VM_WRITE
))
1225 pte
= pte_mkwrite(pte
);
1230 * This routine handles present pages, when users try to write
1231 * to a shared page. It is done by copying the page to a new address
1232 * and decrementing the shared-page counter for the old page.
1234 * Note that this routine assumes that the protection checks have been
1235 * done by the caller (the low-level page fault routine in most cases).
1236 * Thus we can safely just mark it writable once we've done any necessary
1239 * We also mark the page dirty at this point even though the page will
1240 * change only once the write actually happens. This avoids a few races,
1241 * and potentially makes it more efficient.
1243 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1244 * but allow concurrent faults), with pte both mapped and locked.
1245 * We return with mmap_sem still held, but pte unmapped and unlocked.
1247 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1248 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1249 spinlock_t
*ptl
, pte_t orig_pte
)
1251 struct page
*old_page
, *new_page
;
1252 unsigned long pfn
= pte_pfn(orig_pte
);
1254 int ret
= VM_FAULT_MINOR
;
1256 BUG_ON(vma
->vm_flags
& VM_RESERVED
);
1258 if (unlikely(!pfn_valid(pfn
))) {
1260 * Page table corrupted: show pte and kill process.
1262 print_bad_pte(vma
, orig_pte
, address
);
1266 old_page
= pfn_to_page(pfn
);
1268 if (PageAnon(old_page
) && !TestSetPageLocked(old_page
)) {
1269 int reuse
= can_share_swap_page(old_page
);
1270 unlock_page(old_page
);
1272 flush_cache_page(vma
, address
, pfn
);
1273 entry
= pte_mkyoung(orig_pte
);
1274 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1275 ptep_set_access_flags(vma
, address
, page_table
, entry
, 1);
1276 update_mmu_cache(vma
, address
, entry
);
1277 lazy_mmu_prot_update(entry
);
1278 ret
|= VM_FAULT_WRITE
;
1284 * Ok, we need to copy. Oh, well..
1286 page_cache_get(old_page
);
1287 pte_unmap_unlock(page_table
, ptl
);
1289 if (unlikely(anon_vma_prepare(vma
)))
1291 if (old_page
== ZERO_PAGE(address
)) {
1292 new_page
= alloc_zeroed_user_highpage(vma
, address
);
1296 new_page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1299 copy_user_highpage(new_page
, old_page
, address
);
1303 * Re-check the pte - we dropped the lock
1305 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1306 if (likely(pte_same(*page_table
, orig_pte
))) {
1307 page_remove_rmap(old_page
);
1308 if (!PageAnon(old_page
)) {
1309 inc_mm_counter(mm
, anon_rss
);
1310 dec_mm_counter(mm
, file_rss
);
1312 flush_cache_page(vma
, address
, pfn
);
1313 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1314 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1315 ptep_establish(vma
, address
, page_table
, entry
);
1316 update_mmu_cache(vma
, address
, entry
);
1317 lazy_mmu_prot_update(entry
);
1318 lru_cache_add_active(new_page
);
1319 page_add_anon_rmap(new_page
, vma
, address
);
1321 /* Free the old page.. */
1322 new_page
= old_page
;
1323 ret
|= VM_FAULT_WRITE
;
1325 page_cache_release(new_page
);
1326 page_cache_release(old_page
);
1328 pte_unmap_unlock(page_table
, ptl
);
1331 page_cache_release(old_page
);
1332 return VM_FAULT_OOM
;
1336 * Helper functions for unmap_mapping_range().
1338 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1340 * We have to restart searching the prio_tree whenever we drop the lock,
1341 * since the iterator is only valid while the lock is held, and anyway
1342 * a later vma might be split and reinserted earlier while lock dropped.
1344 * The list of nonlinear vmas could be handled more efficiently, using
1345 * a placeholder, but handle it in the same way until a need is shown.
1346 * It is important to search the prio_tree before nonlinear list: a vma
1347 * may become nonlinear and be shifted from prio_tree to nonlinear list
1348 * while the lock is dropped; but never shifted from list to prio_tree.
1350 * In order to make forward progress despite restarting the search,
1351 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1352 * quickly skip it next time around. Since the prio_tree search only
1353 * shows us those vmas affected by unmapping the range in question, we
1354 * can't efficiently keep all vmas in step with mapping->truncate_count:
1355 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1356 * mapping->truncate_count and vma->vm_truncate_count are protected by
1359 * In order to make forward progress despite repeatedly restarting some
1360 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1361 * and restart from that address when we reach that vma again. It might
1362 * have been split or merged, shrunk or extended, but never shifted: so
1363 * restart_addr remains valid so long as it remains in the vma's range.
1364 * unmap_mapping_range forces truncate_count to leap over page-aligned
1365 * values so we can save vma's restart_addr in its truncate_count field.
1367 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1369 static void reset_vma_truncate_counts(struct address_space
*mapping
)
1371 struct vm_area_struct
*vma
;
1372 struct prio_tree_iter iter
;
1374 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
1375 vma
->vm_truncate_count
= 0;
1376 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
1377 vma
->vm_truncate_count
= 0;
1380 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
1381 unsigned long start_addr
, unsigned long end_addr
,
1382 struct zap_details
*details
)
1384 unsigned long restart_addr
;
1388 restart_addr
= vma
->vm_truncate_count
;
1389 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
1390 start_addr
= restart_addr
;
1391 if (start_addr
>= end_addr
) {
1392 /* Top of vma has been split off since last time */
1393 vma
->vm_truncate_count
= details
->truncate_count
;
1398 restart_addr
= zap_page_range(vma
, start_addr
,
1399 end_addr
- start_addr
, details
);
1400 need_break
= need_resched() ||
1401 need_lockbreak(details
->i_mmap_lock
);
1403 if (restart_addr
>= end_addr
) {
1404 /* We have now completed this vma: mark it so */
1405 vma
->vm_truncate_count
= details
->truncate_count
;
1409 /* Note restart_addr in vma's truncate_count field */
1410 vma
->vm_truncate_count
= restart_addr
;
1415 spin_unlock(details
->i_mmap_lock
);
1417 spin_lock(details
->i_mmap_lock
);
1421 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
1422 struct zap_details
*details
)
1424 struct vm_area_struct
*vma
;
1425 struct prio_tree_iter iter
;
1426 pgoff_t vba
, vea
, zba
, zea
;
1429 vma_prio_tree_foreach(vma
, &iter
, root
,
1430 details
->first_index
, details
->last_index
) {
1431 /* Skip quickly over those we have already dealt with */
1432 if (vma
->vm_truncate_count
== details
->truncate_count
)
1435 vba
= vma
->vm_pgoff
;
1436 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
1437 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1438 zba
= details
->first_index
;
1441 zea
= details
->last_index
;
1445 if (unmap_mapping_range_vma(vma
,
1446 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
1447 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
1453 static inline void unmap_mapping_range_list(struct list_head
*head
,
1454 struct zap_details
*details
)
1456 struct vm_area_struct
*vma
;
1459 * In nonlinear VMAs there is no correspondence between virtual address
1460 * offset and file offset. So we must perform an exhaustive search
1461 * across *all* the pages in each nonlinear VMA, not just the pages
1462 * whose virtual address lies outside the file truncation point.
1465 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
1466 /* Skip quickly over those we have already dealt with */
1467 if (vma
->vm_truncate_count
== details
->truncate_count
)
1469 details
->nonlinear_vma
= vma
;
1470 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
1471 vma
->vm_end
, details
) < 0)
1477 * unmap_mapping_range - unmap the portion of all mmaps
1478 * in the specified address_space corresponding to the specified
1479 * page range in the underlying file.
1480 * @mapping: the address space containing mmaps to be unmapped.
1481 * @holebegin: byte in first page to unmap, relative to the start of
1482 * the underlying file. This will be rounded down to a PAGE_SIZE
1483 * boundary. Note that this is different from vmtruncate(), which
1484 * must keep the partial page. In contrast, we must get rid of
1486 * @holelen: size of prospective hole in bytes. This will be rounded
1487 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1489 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1490 * but 0 when invalidating pagecache, don't throw away private data.
1492 void unmap_mapping_range(struct address_space
*mapping
,
1493 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
1495 struct zap_details details
;
1496 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
1497 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1499 /* Check for overflow. */
1500 if (sizeof(holelen
) > sizeof(hlen
)) {
1502 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1503 if (holeend
& ~(long long)ULONG_MAX
)
1504 hlen
= ULONG_MAX
- hba
+ 1;
1507 details
.check_mapping
= even_cows
? NULL
: mapping
;
1508 details
.nonlinear_vma
= NULL
;
1509 details
.first_index
= hba
;
1510 details
.last_index
= hba
+ hlen
- 1;
1511 if (details
.last_index
< details
.first_index
)
1512 details
.last_index
= ULONG_MAX
;
1513 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
1515 spin_lock(&mapping
->i_mmap_lock
);
1517 /* serialize i_size write against truncate_count write */
1519 /* Protect against page faults, and endless unmapping loops */
1520 mapping
->truncate_count
++;
1522 * For archs where spin_lock has inclusive semantics like ia64
1523 * this smp_mb() will prevent to read pagetable contents
1524 * before the truncate_count increment is visible to
1528 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
1529 if (mapping
->truncate_count
== 0)
1530 reset_vma_truncate_counts(mapping
);
1531 mapping
->truncate_count
++;
1533 details
.truncate_count
= mapping
->truncate_count
;
1535 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
1536 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
1537 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
1538 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
1539 spin_unlock(&mapping
->i_mmap_lock
);
1541 EXPORT_SYMBOL(unmap_mapping_range
);
1544 * Handle all mappings that got truncated by a "truncate()"
1547 * NOTE! We have to be ready to update the memory sharing
1548 * between the file and the memory map for a potential last
1549 * incomplete page. Ugly, but necessary.
1551 int vmtruncate(struct inode
* inode
, loff_t offset
)
1553 struct address_space
*mapping
= inode
->i_mapping
;
1554 unsigned long limit
;
1556 if (inode
->i_size
< offset
)
1559 * truncation of in-use swapfiles is disallowed - it would cause
1560 * subsequent swapout to scribble on the now-freed blocks.
1562 if (IS_SWAPFILE(inode
))
1564 i_size_write(inode
, offset
);
1565 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
1566 truncate_inode_pages(mapping
, offset
);
1570 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
1571 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
1573 if (offset
> inode
->i_sb
->s_maxbytes
)
1575 i_size_write(inode
, offset
);
1578 if (inode
->i_op
&& inode
->i_op
->truncate
)
1579 inode
->i_op
->truncate(inode
);
1582 send_sig(SIGXFSZ
, current
, 0);
1589 EXPORT_SYMBOL(vmtruncate
);
1592 * Primitive swap readahead code. We simply read an aligned block of
1593 * (1 << page_cluster) entries in the swap area. This method is chosen
1594 * because it doesn't cost us any seek time. We also make sure to queue
1595 * the 'original' request together with the readahead ones...
1597 * This has been extended to use the NUMA policies from the mm triggering
1600 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1602 void swapin_readahead(swp_entry_t entry
, unsigned long addr
,struct vm_area_struct
*vma
)
1605 struct vm_area_struct
*next_vma
= vma
? vma
->vm_next
: NULL
;
1608 struct page
*new_page
;
1609 unsigned long offset
;
1612 * Get the number of handles we should do readahead io to.
1614 num
= valid_swaphandles(entry
, &offset
);
1615 for (i
= 0; i
< num
; offset
++, i
++) {
1616 /* Ok, do the async read-ahead now */
1617 new_page
= read_swap_cache_async(swp_entry(swp_type(entry
),
1618 offset
), vma
, addr
);
1621 page_cache_release(new_page
);
1624 * Find the next applicable VMA for the NUMA policy.
1630 if (addr
>= vma
->vm_end
) {
1632 next_vma
= vma
? vma
->vm_next
: NULL
;
1634 if (vma
&& addr
< vma
->vm_start
)
1637 if (next_vma
&& addr
>= next_vma
->vm_start
) {
1639 next_vma
= vma
->vm_next
;
1644 lru_add_drain(); /* Push any new pages onto the LRU now */
1648 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1649 * but allow concurrent faults), and pte mapped but not yet locked.
1650 * We return with mmap_sem still held, but pte unmapped and unlocked.
1652 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1653 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1654 int write_access
, pte_t orig_pte
)
1660 int ret
= VM_FAULT_MINOR
;
1662 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
1665 entry
= pte_to_swp_entry(orig_pte
);
1666 page
= lookup_swap_cache(entry
);
1668 swapin_readahead(entry
, address
, vma
);
1669 page
= read_swap_cache_async(entry
, vma
, address
);
1672 * Back out if somebody else faulted in this pte
1673 * while we released the pte lock.
1675 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1676 if (likely(pte_same(*page_table
, orig_pte
)))
1681 /* Had to read the page from swap area: Major fault */
1682 ret
= VM_FAULT_MAJOR
;
1683 inc_page_state(pgmajfault
);
1687 mark_page_accessed(page
);
1691 * Back out if somebody else already faulted in this pte.
1693 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1694 if (unlikely(!pte_same(*page_table
, orig_pte
)))
1697 if (unlikely(!PageUptodate(page
))) {
1698 ret
= VM_FAULT_SIGBUS
;
1702 /* The page isn't present yet, go ahead with the fault. */
1704 inc_mm_counter(mm
, anon_rss
);
1705 pte
= mk_pte(page
, vma
->vm_page_prot
);
1706 if (write_access
&& can_share_swap_page(page
)) {
1707 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
1711 flush_icache_page(vma
, page
);
1712 set_pte_at(mm
, address
, page_table
, pte
);
1713 page_add_anon_rmap(page
, vma
, address
);
1717 remove_exclusive_swap_page(page
);
1721 if (do_wp_page(mm
, vma
, address
,
1722 page_table
, pmd
, ptl
, pte
) == VM_FAULT_OOM
)
1727 /* No need to invalidate - it was non-present before */
1728 update_mmu_cache(vma
, address
, pte
);
1729 lazy_mmu_prot_update(pte
);
1731 pte_unmap_unlock(page_table
, ptl
);
1735 pte_unmap_unlock(page_table
, ptl
);
1737 page_cache_release(page
);
1742 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1743 * but allow concurrent faults), and pte mapped but not yet locked.
1744 * We return with mmap_sem still held, but pte unmapped and unlocked.
1746 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1747 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1755 /* Allocate our own private page. */
1756 pte_unmap(page_table
);
1758 if (unlikely(anon_vma_prepare(vma
)))
1760 page
= alloc_zeroed_user_highpage(vma
, address
);
1764 entry
= mk_pte(page
, vma
->vm_page_prot
);
1765 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1767 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1768 if (!pte_none(*page_table
))
1770 inc_mm_counter(mm
, anon_rss
);
1771 lru_cache_add_active(page
);
1772 SetPageReferenced(page
);
1773 page_add_anon_rmap(page
, vma
, address
);
1775 /* Map the ZERO_PAGE - vm_page_prot is readonly */
1776 page
= ZERO_PAGE(address
);
1777 page_cache_get(page
);
1778 entry
= mk_pte(page
, vma
->vm_page_prot
);
1780 ptl
= pte_lockptr(mm
, pmd
);
1782 if (!pte_none(*page_table
))
1784 inc_mm_counter(mm
, file_rss
);
1785 page_add_file_rmap(page
);
1788 set_pte_at(mm
, address
, page_table
, entry
);
1790 /* No need to invalidate - it was non-present before */
1791 update_mmu_cache(vma
, address
, entry
);
1792 lazy_mmu_prot_update(entry
);
1794 pte_unmap_unlock(page_table
, ptl
);
1795 return VM_FAULT_MINOR
;
1797 page_cache_release(page
);
1800 return VM_FAULT_OOM
;
1804 * do_no_page() tries to create a new page mapping. It aggressively
1805 * tries to share with existing pages, but makes a separate copy if
1806 * the "write_access" parameter is true in order to avoid the next
1809 * As this is called only for pages that do not currently exist, we
1810 * do not need to flush old virtual caches or the TLB.
1812 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1813 * but allow concurrent faults), and pte mapped but not yet locked.
1814 * We return with mmap_sem still held, but pte unmapped and unlocked.
1816 static int do_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1817 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1821 struct page
*new_page
;
1822 struct address_space
*mapping
= NULL
;
1824 unsigned int sequence
= 0;
1825 int ret
= VM_FAULT_MINOR
;
1828 pte_unmap(page_table
);
1831 mapping
= vma
->vm_file
->f_mapping
;
1832 sequence
= mapping
->truncate_count
;
1833 smp_rmb(); /* serializes i_size against truncate_count */
1836 new_page
= vma
->vm_ops
->nopage(vma
, address
& PAGE_MASK
, &ret
);
1838 * No smp_rmb is needed here as long as there's a full
1839 * spin_lock/unlock sequence inside the ->nopage callback
1840 * (for the pagecache lookup) that acts as an implicit
1841 * smp_mb() and prevents the i_size read to happen
1842 * after the next truncate_count read.
1845 /* no page was available -- either SIGBUS or OOM */
1846 if (new_page
== NOPAGE_SIGBUS
)
1847 return VM_FAULT_SIGBUS
;
1848 if (new_page
== NOPAGE_OOM
)
1849 return VM_FAULT_OOM
;
1852 * Should we do an early C-O-W break?
1854 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
1857 if (unlikely(anon_vma_prepare(vma
)))
1859 page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1862 copy_user_highpage(page
, new_page
, address
);
1863 page_cache_release(new_page
);
1868 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1870 * For a file-backed vma, someone could have truncated or otherwise
1871 * invalidated this page. If unmap_mapping_range got called,
1872 * retry getting the page.
1874 if (mapping
&& unlikely(sequence
!= mapping
->truncate_count
)) {
1875 pte_unmap_unlock(page_table
, ptl
);
1876 page_cache_release(new_page
);
1878 sequence
= mapping
->truncate_count
;
1884 * This silly early PAGE_DIRTY setting removes a race
1885 * due to the bad i386 page protection. But it's valid
1886 * for other architectures too.
1888 * Note that if write_access is true, we either now have
1889 * an exclusive copy of the page, or this is a shared mapping,
1890 * so we can make it writable and dirty to avoid having to
1891 * handle that later.
1893 /* Only go through if we didn't race with anybody else... */
1894 if (pte_none(*page_table
)) {
1895 flush_icache_page(vma
, new_page
);
1896 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1898 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1899 set_pte_at(mm
, address
, page_table
, entry
);
1901 inc_mm_counter(mm
, anon_rss
);
1902 lru_cache_add_active(new_page
);
1903 page_add_anon_rmap(new_page
, vma
, address
);
1904 } else if (!(vma
->vm_flags
& VM_RESERVED
)) {
1905 inc_mm_counter(mm
, file_rss
);
1906 page_add_file_rmap(new_page
);
1909 /* One of our sibling threads was faster, back out. */
1910 page_cache_release(new_page
);
1914 /* no need to invalidate: a not-present page shouldn't be cached */
1915 update_mmu_cache(vma
, address
, entry
);
1916 lazy_mmu_prot_update(entry
);
1918 pte_unmap_unlock(page_table
, ptl
);
1921 page_cache_release(new_page
);
1922 return VM_FAULT_OOM
;
1926 * Fault of a previously existing named mapping. Repopulate the pte
1927 * from the encoded file_pte if possible. This enables swappable
1930 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1931 * but allow concurrent faults), and pte mapped but not yet locked.
1932 * We return with mmap_sem still held, but pte unmapped and unlocked.
1934 static int do_file_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1935 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1936 int write_access
, pte_t orig_pte
)
1941 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
1942 return VM_FAULT_MINOR
;
1944 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
1946 * Page table corrupted: show pte and kill process.
1948 print_bad_pte(vma
, orig_pte
, address
);
1949 return VM_FAULT_OOM
;
1951 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
1953 pgoff
= pte_to_pgoff(orig_pte
);
1954 err
= vma
->vm_ops
->populate(vma
, address
& PAGE_MASK
, PAGE_SIZE
,
1955 vma
->vm_page_prot
, pgoff
, 0);
1957 return VM_FAULT_OOM
;
1959 return VM_FAULT_SIGBUS
;
1960 return VM_FAULT_MAJOR
;
1964 * These routines also need to handle stuff like marking pages dirty
1965 * and/or accessed for architectures that don't do it in hardware (most
1966 * RISC architectures). The early dirtying is also good on the i386.
1968 * There is also a hook called "update_mmu_cache()" that architectures
1969 * with external mmu caches can use to update those (ie the Sparc or
1970 * PowerPC hashed page tables that act as extended TLBs).
1972 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1973 * but allow concurrent faults), and pte mapped but not yet locked.
1974 * We return with mmap_sem still held, but pte unmapped and unlocked.
1976 static inline int handle_pte_fault(struct mm_struct
*mm
,
1977 struct vm_area_struct
*vma
, unsigned long address
,
1978 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
1984 if (!pte_present(entry
)) {
1985 if (pte_none(entry
)) {
1986 if (!vma
->vm_ops
|| !vma
->vm_ops
->nopage
)
1987 return do_anonymous_page(mm
, vma
, address
,
1988 pte
, pmd
, write_access
);
1989 return do_no_page(mm
, vma
, address
,
1990 pte
, pmd
, write_access
);
1992 if (pte_file(entry
))
1993 return do_file_page(mm
, vma
, address
,
1994 pte
, pmd
, write_access
, entry
);
1995 return do_swap_page(mm
, vma
, address
,
1996 pte
, pmd
, write_access
, entry
);
1999 ptl
= pte_lockptr(mm
, pmd
);
2001 if (unlikely(!pte_same(*pte
, entry
)))
2004 if (!pte_write(entry
))
2005 return do_wp_page(mm
, vma
, address
,
2006 pte
, pmd
, ptl
, entry
);
2007 entry
= pte_mkdirty(entry
);
2009 entry
= pte_mkyoung(entry
);
2010 ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
);
2011 update_mmu_cache(vma
, address
, entry
);
2012 lazy_mmu_prot_update(entry
);
2014 pte_unmap_unlock(pte
, ptl
);
2015 return VM_FAULT_MINOR
;
2019 * By the time we get here, we already hold the mm semaphore
2021 int __handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2022 unsigned long address
, int write_access
)
2029 __set_current_state(TASK_RUNNING
);
2031 inc_page_state(pgfault
);
2033 if (unlikely(is_vm_hugetlb_page(vma
)))
2034 return hugetlb_fault(mm
, vma
, address
, write_access
);
2036 pgd
= pgd_offset(mm
, address
);
2037 pud
= pud_alloc(mm
, pgd
, address
);
2039 return VM_FAULT_OOM
;
2040 pmd
= pmd_alloc(mm
, pud
, address
);
2042 return VM_FAULT_OOM
;
2043 pte
= pte_alloc_map(mm
, pmd
, address
);
2045 return VM_FAULT_OOM
;
2047 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2050 #ifndef __PAGETABLE_PUD_FOLDED
2052 * Allocate page upper directory.
2053 * We've already handled the fast-path in-line.
2055 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2057 pud_t
*new = pud_alloc_one(mm
, address
);
2061 spin_lock(&mm
->page_table_lock
);
2062 if (pgd_present(*pgd
)) /* Another has populated it */
2065 pgd_populate(mm
, pgd
, new);
2066 spin_unlock(&mm
->page_table_lock
);
2069 #endif /* __PAGETABLE_PUD_FOLDED */
2071 #ifndef __PAGETABLE_PMD_FOLDED
2073 * Allocate page middle directory.
2074 * We've already handled the fast-path in-line.
2076 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2078 pmd_t
*new = pmd_alloc_one(mm
, address
);
2082 spin_lock(&mm
->page_table_lock
);
2083 #ifndef __ARCH_HAS_4LEVEL_HACK
2084 if (pud_present(*pud
)) /* Another has populated it */
2087 pud_populate(mm
, pud
, new);
2089 if (pgd_present(*pud
)) /* Another has populated it */
2092 pgd_populate(mm
, pud
, new);
2093 #endif /* __ARCH_HAS_4LEVEL_HACK */
2094 spin_unlock(&mm
->page_table_lock
);
2097 #endif /* __PAGETABLE_PMD_FOLDED */
2099 int make_pages_present(unsigned long addr
, unsigned long end
)
2101 int ret
, len
, write
;
2102 struct vm_area_struct
* vma
;
2104 vma
= find_vma(current
->mm
, addr
);
2107 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2110 if (end
> vma
->vm_end
)
2112 len
= (end
+PAGE_SIZE
-1)/PAGE_SIZE
-addr
/PAGE_SIZE
;
2113 ret
= get_user_pages(current
, current
->mm
, addr
,
2114 len
, write
, 0, NULL
, NULL
);
2117 return ret
== len
? 0 : -1;
2121 * Map a vmalloc()-space virtual address to the physical page.
2123 struct page
* vmalloc_to_page(void * vmalloc_addr
)
2125 unsigned long addr
= (unsigned long) vmalloc_addr
;
2126 struct page
*page
= NULL
;
2127 pgd_t
*pgd
= pgd_offset_k(addr
);
2132 if (!pgd_none(*pgd
)) {
2133 pud
= pud_offset(pgd
, addr
);
2134 if (!pud_none(*pud
)) {
2135 pmd
= pmd_offset(pud
, addr
);
2136 if (!pmd_none(*pmd
)) {
2137 ptep
= pte_offset_map(pmd
, addr
);
2139 if (pte_present(pte
))
2140 page
= pte_page(pte
);
2148 EXPORT_SYMBOL(vmalloc_to_page
);
2151 * Map a vmalloc()-space virtual address to the physical page frame number.
2153 unsigned long vmalloc_to_pfn(void * vmalloc_addr
)
2155 return page_to_pfn(vmalloc_to_page(vmalloc_addr
));
2158 EXPORT_SYMBOL(vmalloc_to_pfn
);
2160 #if !defined(__HAVE_ARCH_GATE_AREA)
2162 #if defined(AT_SYSINFO_EHDR)
2163 static struct vm_area_struct gate_vma
;
2165 static int __init
gate_vma_init(void)
2167 gate_vma
.vm_mm
= NULL
;
2168 gate_vma
.vm_start
= FIXADDR_USER_START
;
2169 gate_vma
.vm_end
= FIXADDR_USER_END
;
2170 gate_vma
.vm_page_prot
= PAGE_READONLY
;
2171 gate_vma
.vm_flags
= VM_RESERVED
;
2174 __initcall(gate_vma_init
);
2177 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2179 #ifdef AT_SYSINFO_EHDR
2186 int in_gate_area_no_task(unsigned long addr
)
2188 #ifdef AT_SYSINFO_EHDR
2189 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2195 #endif /* __HAVE_ARCH_GATE_AREA */