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/delayacct.h>
51 #include <linux/init.h>
52 #include <linux/writeback.h>
54 #include <asm/pgalloc.h>
55 #include <asm/uaccess.h>
57 #include <asm/tlbflush.h>
58 #include <asm/pgtable.h>
60 #include <linux/swapops.h>
61 #include <linux/elf.h>
63 #ifndef CONFIG_NEED_MULTIPLE_NODES
64 /* use the per-pgdat data instead for discontigmem - mbligh */
65 unsigned long max_mapnr
;
68 EXPORT_SYMBOL(max_mapnr
);
69 EXPORT_SYMBOL(mem_map
);
72 unsigned long num_physpages
;
74 * A number of key systems in x86 including ioremap() rely on the assumption
75 * that high_memory defines the upper bound on direct map memory, then end
76 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
77 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
82 EXPORT_SYMBOL(num_physpages
);
83 EXPORT_SYMBOL(high_memory
);
85 int randomize_va_space __read_mostly
= 1;
87 static int __init
disable_randmaps(char *s
)
89 randomize_va_space
= 0;
92 __setup("norandmaps", disable_randmaps
);
96 * If a p?d_bad entry is found while walking page tables, report
97 * the error, before resetting entry to p?d_none. Usually (but
98 * very seldom) called out from the p?d_none_or_clear_bad macros.
101 void pgd_clear_bad(pgd_t
*pgd
)
107 void pud_clear_bad(pud_t
*pud
)
113 void pmd_clear_bad(pmd_t
*pmd
)
120 * Note: this doesn't free the actual pages themselves. That
121 * has been handled earlier when unmapping all the memory regions.
123 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
)
125 struct page
*page
= pmd_page(*pmd
);
127 pte_lock_deinit(page
);
128 pte_free_tlb(tlb
, page
);
129 dec_zone_page_state(page
, NR_PAGETABLE
);
133 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
134 unsigned long addr
, unsigned long end
,
135 unsigned long floor
, unsigned long ceiling
)
142 pmd
= pmd_offset(pud
, addr
);
144 next
= pmd_addr_end(addr
, end
);
145 if (pmd_none_or_clear_bad(pmd
))
147 free_pte_range(tlb
, pmd
);
148 } while (pmd
++, addr
= next
, addr
!= end
);
158 if (end
- 1 > ceiling
- 1)
161 pmd
= pmd_offset(pud
, start
);
163 pmd_free_tlb(tlb
, pmd
);
166 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
167 unsigned long addr
, unsigned long end
,
168 unsigned long floor
, unsigned long ceiling
)
175 pud
= pud_offset(pgd
, addr
);
177 next
= pud_addr_end(addr
, end
);
178 if (pud_none_or_clear_bad(pud
))
180 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
181 } while (pud
++, addr
= next
, addr
!= end
);
187 ceiling
&= PGDIR_MASK
;
191 if (end
- 1 > ceiling
- 1)
194 pud
= pud_offset(pgd
, start
);
196 pud_free_tlb(tlb
, pud
);
200 * This function frees user-level page tables of a process.
202 * Must be called with pagetable lock held.
204 void free_pgd_range(struct mmu_gather
**tlb
,
205 unsigned long addr
, unsigned long end
,
206 unsigned long floor
, unsigned long ceiling
)
213 * The next few lines have given us lots of grief...
215 * Why are we testing PMD* at this top level? Because often
216 * there will be no work to do at all, and we'd prefer not to
217 * go all the way down to the bottom just to discover that.
219 * Why all these "- 1"s? Because 0 represents both the bottom
220 * of the address space and the top of it (using -1 for the
221 * top wouldn't help much: the masks would do the wrong thing).
222 * The rule is that addr 0 and floor 0 refer to the bottom of
223 * the address space, but end 0 and ceiling 0 refer to the top
224 * Comparisons need to use "end - 1" and "ceiling - 1" (though
225 * that end 0 case should be mythical).
227 * Wherever addr is brought up or ceiling brought down, we must
228 * be careful to reject "the opposite 0" before it confuses the
229 * subsequent tests. But what about where end is brought down
230 * by PMD_SIZE below? no, end can't go down to 0 there.
232 * Whereas we round start (addr) and ceiling down, by different
233 * masks at different levels, in order to test whether a table
234 * now has no other vmas using it, so can be freed, we don't
235 * bother to round floor or end up - the tests don't need that.
249 if (end
- 1 > ceiling
- 1)
255 pgd
= pgd_offset((*tlb
)->mm
, addr
);
257 next
= pgd_addr_end(addr
, end
);
258 if (pgd_none_or_clear_bad(pgd
))
260 free_pud_range(*tlb
, pgd
, addr
, next
, floor
, ceiling
);
261 } while (pgd
++, addr
= next
, addr
!= end
);
264 flush_tlb_pgtables((*tlb
)->mm
, start
, end
);
267 void free_pgtables(struct mmu_gather
**tlb
, struct vm_area_struct
*vma
,
268 unsigned long floor
, unsigned long ceiling
)
271 struct vm_area_struct
*next
= vma
->vm_next
;
272 unsigned long addr
= vma
->vm_start
;
275 * Hide vma from rmap and vmtruncate before freeing pgtables
277 anon_vma_unlink(vma
);
278 unlink_file_vma(vma
);
280 if (is_vm_hugetlb_page(vma
)) {
281 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
282 floor
, next
? next
->vm_start
: ceiling
);
285 * Optimization: gather nearby vmas into one call down
287 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
288 && !is_vm_hugetlb_page(next
)) {
291 anon_vma_unlink(vma
);
292 unlink_file_vma(vma
);
294 free_pgd_range(tlb
, addr
, vma
->vm_end
,
295 floor
, next
? next
->vm_start
: ceiling
);
301 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
303 struct page
*new = pte_alloc_one(mm
, address
);
308 spin_lock(&mm
->page_table_lock
);
309 if (pmd_present(*pmd
)) { /* Another has populated it */
310 pte_lock_deinit(new);
314 inc_zone_page_state(new, NR_PAGETABLE
);
315 pmd_populate(mm
, pmd
, new);
317 spin_unlock(&mm
->page_table_lock
);
321 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
323 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
327 spin_lock(&init_mm
.page_table_lock
);
328 if (pmd_present(*pmd
)) /* Another has populated it */
329 pte_free_kernel(new);
331 pmd_populate_kernel(&init_mm
, pmd
, new);
332 spin_unlock(&init_mm
.page_table_lock
);
336 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
339 add_mm_counter(mm
, file_rss
, file_rss
);
341 add_mm_counter(mm
, anon_rss
, anon_rss
);
345 * This function is called to print an error when a bad pte
346 * is found. For example, we might have a PFN-mapped pte in
347 * a region that doesn't allow it.
349 * The calling function must still handle the error.
351 void print_bad_pte(struct vm_area_struct
*vma
, pte_t pte
, unsigned long vaddr
)
353 printk(KERN_ERR
"Bad pte = %08llx, process = %s, "
354 "vm_flags = %lx, vaddr = %lx\n",
355 (long long)pte_val(pte
),
356 (vma
->vm_mm
== current
->mm
? current
->comm
: "???"),
357 vma
->vm_flags
, vaddr
);
361 static inline int is_cow_mapping(unsigned int flags
)
363 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
367 * This function gets the "struct page" associated with a pte.
369 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
370 * will have each page table entry just pointing to a raw page frame
371 * number, and as far as the VM layer is concerned, those do not have
372 * pages associated with them - even if the PFN might point to memory
373 * that otherwise is perfectly fine and has a "struct page".
375 * The way we recognize those mappings is through the rules set up
376 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
377 * and the vm_pgoff will point to the first PFN mapped: thus every
378 * page that is a raw mapping will always honor the rule
380 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
382 * and if that isn't true, the page has been COW'ed (in which case it
383 * _does_ have a "struct page" associated with it even if it is in a
386 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
, pte_t pte
)
388 unsigned long pfn
= pte_pfn(pte
);
390 if (unlikely(vma
->vm_flags
& VM_PFNMAP
)) {
391 unsigned long off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
392 if (pfn
== vma
->vm_pgoff
+ off
)
394 if (!is_cow_mapping(vma
->vm_flags
))
399 * Add some anal sanity checks for now. Eventually,
400 * we should just do "return pfn_to_page(pfn)", but
401 * in the meantime we check that we get a valid pfn,
402 * and that the resulting page looks ok.
404 if (unlikely(!pfn_valid(pfn
))) {
405 print_bad_pte(vma
, pte
, addr
);
410 * NOTE! We still have PageReserved() pages in the page
413 * The PAGE_ZERO() pages and various VDSO mappings can
414 * cause them to exist.
416 return pfn_to_page(pfn
);
420 * copy one vm_area from one task to the other. Assumes the page tables
421 * already present in the new task to be cleared in the whole range
422 * covered by this vma.
426 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
427 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
428 unsigned long addr
, int *rss
)
430 unsigned long vm_flags
= vma
->vm_flags
;
431 pte_t pte
= *src_pte
;
434 /* pte contains position in swap or file, so copy. */
435 if (unlikely(!pte_present(pte
))) {
436 if (!pte_file(pte
)) {
437 swp_entry_t entry
= pte_to_swp_entry(pte
);
439 swap_duplicate(entry
);
440 /* make sure dst_mm is on swapoff's mmlist. */
441 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
442 spin_lock(&mmlist_lock
);
443 if (list_empty(&dst_mm
->mmlist
))
444 list_add(&dst_mm
->mmlist
,
446 spin_unlock(&mmlist_lock
);
448 if (is_write_migration_entry(entry
) &&
449 is_cow_mapping(vm_flags
)) {
451 * COW mappings require pages in both parent
452 * and child to be set to read.
454 make_migration_entry_read(&entry
);
455 pte
= swp_entry_to_pte(entry
);
456 set_pte_at(src_mm
, addr
, src_pte
, pte
);
463 * If it's a COW mapping, write protect it both
464 * in the parent and the child
466 if (is_cow_mapping(vm_flags
)) {
467 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
468 pte
= pte_wrprotect(pte
);
472 * If it's a shared mapping, mark it clean in
475 if (vm_flags
& VM_SHARED
)
476 pte
= pte_mkclean(pte
);
477 pte
= pte_mkold(pte
);
479 page
= vm_normal_page(vma
, addr
, pte
);
482 page_dup_rmap(page
, vma
, addr
);
483 rss
[!!PageAnon(page
)]++;
487 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
490 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
491 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
492 unsigned long addr
, unsigned long end
)
494 pte_t
*src_pte
, *dst_pte
;
495 spinlock_t
*src_ptl
, *dst_ptl
;
501 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
504 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
505 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
506 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
507 arch_enter_lazy_mmu_mode();
511 * We are holding two locks at this point - either of them
512 * could generate latencies in another task on another CPU.
514 if (progress
>= 32) {
516 if (need_resched() ||
517 need_lockbreak(src_ptl
) ||
518 need_lockbreak(dst_ptl
))
521 if (pte_none(*src_pte
)) {
525 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
527 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
529 arch_leave_lazy_mmu_mode();
530 spin_unlock(src_ptl
);
531 pte_unmap_nested(src_pte
- 1);
532 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
533 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
540 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
541 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
542 unsigned long addr
, unsigned long end
)
544 pmd_t
*src_pmd
, *dst_pmd
;
547 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
550 src_pmd
= pmd_offset(src_pud
, addr
);
552 next
= pmd_addr_end(addr
, end
);
553 if (pmd_none_or_clear_bad(src_pmd
))
555 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
558 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
562 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
563 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
564 unsigned long addr
, unsigned long end
)
566 pud_t
*src_pud
, *dst_pud
;
569 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
572 src_pud
= pud_offset(src_pgd
, addr
);
574 next
= pud_addr_end(addr
, end
);
575 if (pud_none_or_clear_bad(src_pud
))
577 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
580 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
584 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
585 struct vm_area_struct
*vma
)
587 pgd_t
*src_pgd
, *dst_pgd
;
589 unsigned long addr
= vma
->vm_start
;
590 unsigned long end
= vma
->vm_end
;
593 * Don't copy ptes where a page fault will fill them correctly.
594 * Fork becomes much lighter when there are big shared or private
595 * readonly mappings. The tradeoff is that copy_page_range is more
596 * efficient than faulting.
598 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
603 if (is_vm_hugetlb_page(vma
))
604 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
606 dst_pgd
= pgd_offset(dst_mm
, addr
);
607 src_pgd
= pgd_offset(src_mm
, addr
);
609 next
= pgd_addr_end(addr
, end
);
610 if (pgd_none_or_clear_bad(src_pgd
))
612 if (copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
615 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
619 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
620 struct vm_area_struct
*vma
, pmd_t
*pmd
,
621 unsigned long addr
, unsigned long end
,
622 long *zap_work
, struct zap_details
*details
)
624 struct mm_struct
*mm
= tlb
->mm
;
630 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
631 arch_enter_lazy_mmu_mode();
634 if (pte_none(ptent
)) {
639 (*zap_work
) -= PAGE_SIZE
;
641 if (pte_present(ptent
)) {
644 page
= vm_normal_page(vma
, addr
, ptent
);
645 if (unlikely(details
) && page
) {
647 * unmap_shared_mapping_pages() wants to
648 * invalidate cache without truncating:
649 * unmap shared but keep private pages.
651 if (details
->check_mapping
&&
652 details
->check_mapping
!= page
->mapping
)
655 * Each page->index must be checked when
656 * invalidating or truncating nonlinear.
658 if (details
->nonlinear_vma
&&
659 (page
->index
< details
->first_index
||
660 page
->index
> details
->last_index
))
663 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
665 tlb_remove_tlb_entry(tlb
, pte
, addr
);
668 if (unlikely(details
) && details
->nonlinear_vma
669 && linear_page_index(details
->nonlinear_vma
,
670 addr
) != page
->index
)
671 set_pte_at(mm
, addr
, pte
,
672 pgoff_to_pte(page
->index
));
676 if (pte_dirty(ptent
))
677 set_page_dirty(page
);
678 if (pte_young(ptent
))
679 SetPageReferenced(page
);
682 page_remove_rmap(page
, vma
);
683 tlb_remove_page(tlb
, page
);
687 * If details->check_mapping, we leave swap entries;
688 * if details->nonlinear_vma, we leave file entries.
690 if (unlikely(details
))
692 if (!pte_file(ptent
))
693 free_swap_and_cache(pte_to_swp_entry(ptent
));
694 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
695 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
697 add_mm_rss(mm
, file_rss
, anon_rss
);
698 arch_leave_lazy_mmu_mode();
699 pte_unmap_unlock(pte
- 1, ptl
);
704 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
705 struct vm_area_struct
*vma
, pud_t
*pud
,
706 unsigned long addr
, unsigned long end
,
707 long *zap_work
, struct zap_details
*details
)
712 pmd
= pmd_offset(pud
, addr
);
714 next
= pmd_addr_end(addr
, end
);
715 if (pmd_none_or_clear_bad(pmd
)) {
719 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
721 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
726 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
727 struct vm_area_struct
*vma
, pgd_t
*pgd
,
728 unsigned long addr
, unsigned long end
,
729 long *zap_work
, struct zap_details
*details
)
734 pud
= pud_offset(pgd
, addr
);
736 next
= pud_addr_end(addr
, end
);
737 if (pud_none_or_clear_bad(pud
)) {
741 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
743 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
748 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
749 struct vm_area_struct
*vma
,
750 unsigned long addr
, unsigned long end
,
751 long *zap_work
, struct zap_details
*details
)
756 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
760 tlb_start_vma(tlb
, vma
);
761 pgd
= pgd_offset(vma
->vm_mm
, addr
);
763 next
= pgd_addr_end(addr
, end
);
764 if (pgd_none_or_clear_bad(pgd
)) {
768 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
770 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
771 tlb_end_vma(tlb
, vma
);
776 #ifdef CONFIG_PREEMPT
777 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
779 /* No preempt: go for improved straight-line efficiency */
780 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
784 * unmap_vmas - unmap a range of memory covered by a list of vma's
785 * @tlbp: address of the caller's struct mmu_gather
786 * @vma: the starting vma
787 * @start_addr: virtual address at which to start unmapping
788 * @end_addr: virtual address at which to end unmapping
789 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
790 * @details: details of nonlinear truncation or shared cache invalidation
792 * Returns the end address of the unmapping (restart addr if interrupted).
794 * Unmap all pages in the vma list.
796 * We aim to not hold locks for too long (for scheduling latency reasons).
797 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
798 * return the ending mmu_gather to the caller.
800 * Only addresses between `start' and `end' will be unmapped.
802 * The VMA list must be sorted in ascending virtual address order.
804 * unmap_vmas() assumes that the caller will flush the whole unmapped address
805 * range after unmap_vmas() returns. So the only responsibility here is to
806 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
807 * drops the lock and schedules.
809 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
810 struct vm_area_struct
*vma
, unsigned long start_addr
,
811 unsigned long end_addr
, unsigned long *nr_accounted
,
812 struct zap_details
*details
)
814 long zap_work
= ZAP_BLOCK_SIZE
;
815 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
816 int tlb_start_valid
= 0;
817 unsigned long start
= start_addr
;
818 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
819 int fullmm
= (*tlbp
)->fullmm
;
821 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
824 start
= max(vma
->vm_start
, start_addr
);
825 if (start
>= vma
->vm_end
)
827 end
= min(vma
->vm_end
, end_addr
);
828 if (end
<= vma
->vm_start
)
831 if (vma
->vm_flags
& VM_ACCOUNT
)
832 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
834 while (start
!= end
) {
835 if (!tlb_start_valid
) {
840 if (unlikely(is_vm_hugetlb_page(vma
))) {
841 unmap_hugepage_range(vma
, start
, end
);
842 zap_work
-= (end
- start
) /
843 (HPAGE_SIZE
/ PAGE_SIZE
);
846 start
= unmap_page_range(*tlbp
, vma
,
847 start
, end
, &zap_work
, details
);
850 BUG_ON(start
!= end
);
854 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
856 if (need_resched() ||
857 (i_mmap_lock
&& need_lockbreak(i_mmap_lock
))) {
865 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
867 zap_work
= ZAP_BLOCK_SIZE
;
871 return start
; /* which is now the end (or restart) address */
875 * zap_page_range - remove user pages in a given range
876 * @vma: vm_area_struct holding the applicable pages
877 * @address: starting address of pages to zap
878 * @size: number of bytes to zap
879 * @details: details of nonlinear truncation or shared cache invalidation
881 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
882 unsigned long size
, struct zap_details
*details
)
884 struct mm_struct
*mm
= vma
->vm_mm
;
885 struct mmu_gather
*tlb
;
886 unsigned long end
= address
+ size
;
887 unsigned long nr_accounted
= 0;
890 tlb
= tlb_gather_mmu(mm
, 0);
891 update_hiwater_rss(mm
);
892 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
894 tlb_finish_mmu(tlb
, address
, end
);
899 * Do a quick page-table lookup for a single page.
901 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
910 struct mm_struct
*mm
= vma
->vm_mm
;
912 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
914 BUG_ON(flags
& FOLL_GET
);
919 pgd
= pgd_offset(mm
, address
);
920 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
923 pud
= pud_offset(pgd
, address
);
924 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
927 pmd
= pmd_offset(pud
, address
);
928 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
931 if (pmd_huge(*pmd
)) {
932 BUG_ON(flags
& FOLL_GET
);
933 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
937 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
942 if (!pte_present(pte
))
944 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
946 page
= vm_normal_page(vma
, address
, pte
);
950 if (flags
& FOLL_GET
)
952 if (flags
& FOLL_TOUCH
) {
953 if ((flags
& FOLL_WRITE
) &&
954 !pte_dirty(pte
) && !PageDirty(page
))
955 set_page_dirty(page
);
956 mark_page_accessed(page
);
959 pte_unmap_unlock(ptep
, ptl
);
965 * When core dumping an enormous anonymous area that nobody
966 * has touched so far, we don't want to allocate page tables.
968 if (flags
& FOLL_ANON
) {
970 if (flags
& FOLL_GET
)
972 BUG_ON(flags
& FOLL_WRITE
);
977 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
978 unsigned long start
, int len
, int write
, int force
,
979 struct page
**pages
, struct vm_area_struct
**vmas
)
982 unsigned int vm_flags
;
985 * Require read or write permissions.
986 * If 'force' is set, we only require the "MAY" flags.
988 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
989 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
993 struct vm_area_struct
*vma
;
994 unsigned int foll_flags
;
996 vma
= find_extend_vma(mm
, start
);
997 if (!vma
&& in_gate_area(tsk
, start
)) {
998 unsigned long pg
= start
& PAGE_MASK
;
999 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1004 if (write
) /* user gate pages are read-only */
1005 return i
? : -EFAULT
;
1007 pgd
= pgd_offset_k(pg
);
1009 pgd
= pgd_offset_gate(mm
, pg
);
1010 BUG_ON(pgd_none(*pgd
));
1011 pud
= pud_offset(pgd
, pg
);
1012 BUG_ON(pud_none(*pud
));
1013 pmd
= pmd_offset(pud
, pg
);
1015 return i
? : -EFAULT
;
1016 pte
= pte_offset_map(pmd
, pg
);
1017 if (pte_none(*pte
)) {
1019 return i
? : -EFAULT
;
1022 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1036 if (!vma
|| (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
))
1037 || !(vm_flags
& vma
->vm_flags
))
1038 return i
? : -EFAULT
;
1040 if (is_vm_hugetlb_page(vma
)) {
1041 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1046 foll_flags
= FOLL_TOUCH
;
1048 foll_flags
|= FOLL_GET
;
1049 if (!write
&& !(vma
->vm_flags
& VM_LOCKED
) &&
1050 (!vma
->vm_ops
|| (!vma
->vm_ops
->nopage
&&
1051 !vma
->vm_ops
->fault
)))
1052 foll_flags
|= FOLL_ANON
;
1058 * If tsk is ooming, cut off its access to large memory
1059 * allocations. It has a pending SIGKILL, but it can't
1060 * be processed until returning to user space.
1062 if (unlikely(test_tsk_thread_flag(tsk
, TIF_MEMDIE
)))
1066 foll_flags
|= FOLL_WRITE
;
1069 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1071 ret
= handle_mm_fault(mm
, vma
, start
,
1072 foll_flags
& FOLL_WRITE
);
1073 if (ret
& VM_FAULT_ERROR
) {
1074 if (ret
& VM_FAULT_OOM
)
1075 return i
? i
: -ENOMEM
;
1076 else if (ret
& VM_FAULT_SIGBUS
)
1077 return i
? i
: -EFAULT
;
1080 if (ret
& VM_FAULT_MAJOR
)
1086 * The VM_FAULT_WRITE bit tells us that
1087 * do_wp_page has broken COW when necessary,
1088 * even if maybe_mkwrite decided not to set
1089 * pte_write. We can thus safely do subsequent
1090 * page lookups as if they were reads.
1092 if (ret
& VM_FAULT_WRITE
)
1093 foll_flags
&= ~FOLL_WRITE
;
1100 flush_anon_page(vma
, page
, start
);
1101 flush_dcache_page(page
);
1108 } while (len
&& start
< vma
->vm_end
);
1112 EXPORT_SYMBOL(get_user_pages
);
1114 pte_t
* fastcall
get_locked_pte(struct mm_struct
*mm
, unsigned long addr
, spinlock_t
**ptl
)
1116 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1117 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1119 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1121 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1127 * This is the old fallback for page remapping.
1129 * For historical reasons, it only allows reserved pages. Only
1130 * old drivers should use this, and they needed to mark their
1131 * pages reserved for the old functions anyway.
1133 static int insert_page(struct mm_struct
*mm
, unsigned long addr
, struct page
*page
, pgprot_t prot
)
1143 flush_dcache_page(page
);
1144 pte
= get_locked_pte(mm
, addr
, &ptl
);
1148 if (!pte_none(*pte
))
1151 /* Ok, finally just insert the thing.. */
1153 inc_mm_counter(mm
, file_rss
);
1154 page_add_file_rmap(page
);
1155 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1159 pte_unmap_unlock(pte
, ptl
);
1165 * vm_insert_page - insert single page into user vma
1166 * @vma: user vma to map to
1167 * @addr: target user address of this page
1168 * @page: source kernel page
1170 * This allows drivers to insert individual pages they've allocated
1173 * The page has to be a nice clean _individual_ kernel allocation.
1174 * If you allocate a compound page, you need to have marked it as
1175 * such (__GFP_COMP), or manually just split the page up yourself
1176 * (see split_page()).
1178 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1179 * took an arbitrary page protection parameter. This doesn't allow
1180 * that. Your vma protection will have to be set up correctly, which
1181 * means that if you want a shared writable mapping, you'd better
1182 * ask for a shared writable mapping!
1184 * The page does not need to be reserved.
1186 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
, struct page
*page
)
1188 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1190 if (!page_count(page
))
1192 vma
->vm_flags
|= VM_INSERTPAGE
;
1193 return insert_page(vma
->vm_mm
, addr
, page
, vma
->vm_page_prot
);
1195 EXPORT_SYMBOL(vm_insert_page
);
1198 * vm_insert_pfn - insert single pfn into user vma
1199 * @vma: user vma to map to
1200 * @addr: target user address of this page
1201 * @pfn: source kernel pfn
1203 * Similar to vm_inert_page, this allows drivers to insert individual pages
1204 * they've allocated into a user vma. Same comments apply.
1206 * This function should only be called from a vm_ops->fault handler, and
1207 * in that case the handler should return NULL.
1209 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1212 struct mm_struct
*mm
= vma
->vm_mm
;
1217 BUG_ON(!(vma
->vm_flags
& VM_PFNMAP
));
1218 BUG_ON(is_cow_mapping(vma
->vm_flags
));
1221 pte
= get_locked_pte(mm
, addr
, &ptl
);
1225 if (!pte_none(*pte
))
1228 /* Ok, finally just insert the thing.. */
1229 entry
= pfn_pte(pfn
, vma
->vm_page_prot
);
1230 set_pte_at(mm
, addr
, pte
, entry
);
1231 update_mmu_cache(vma
, addr
, entry
);
1235 pte_unmap_unlock(pte
, ptl
);
1240 EXPORT_SYMBOL(vm_insert_pfn
);
1243 * maps a range of physical memory into the requested pages. the old
1244 * mappings are removed. any references to nonexistent pages results
1245 * in null mappings (currently treated as "copy-on-access")
1247 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1248 unsigned long addr
, unsigned long end
,
1249 unsigned long pfn
, pgprot_t prot
)
1254 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1257 arch_enter_lazy_mmu_mode();
1259 BUG_ON(!pte_none(*pte
));
1260 set_pte_at(mm
, addr
, pte
, pfn_pte(pfn
, prot
));
1262 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1263 arch_leave_lazy_mmu_mode();
1264 pte_unmap_unlock(pte
- 1, ptl
);
1268 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1269 unsigned long addr
, unsigned long end
,
1270 unsigned long pfn
, pgprot_t prot
)
1275 pfn
-= addr
>> PAGE_SHIFT
;
1276 pmd
= pmd_alloc(mm
, pud
, addr
);
1280 next
= pmd_addr_end(addr
, end
);
1281 if (remap_pte_range(mm
, pmd
, addr
, next
,
1282 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1284 } while (pmd
++, addr
= next
, addr
!= end
);
1288 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1289 unsigned long addr
, unsigned long end
,
1290 unsigned long pfn
, pgprot_t prot
)
1295 pfn
-= addr
>> PAGE_SHIFT
;
1296 pud
= pud_alloc(mm
, pgd
, addr
);
1300 next
= pud_addr_end(addr
, end
);
1301 if (remap_pmd_range(mm
, pud
, addr
, next
,
1302 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1304 } while (pud
++, addr
= next
, addr
!= end
);
1309 * remap_pfn_range - remap kernel memory to userspace
1310 * @vma: user vma to map to
1311 * @addr: target user address to start at
1312 * @pfn: physical address of kernel memory
1313 * @size: size of map area
1314 * @prot: page protection flags for this mapping
1316 * Note: this is only safe if the mm semaphore is held when called.
1318 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1319 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1323 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1324 struct mm_struct
*mm
= vma
->vm_mm
;
1328 * Physically remapped pages are special. Tell the
1329 * rest of the world about it:
1330 * VM_IO tells people not to look at these pages
1331 * (accesses can have side effects).
1332 * VM_RESERVED is specified all over the place, because
1333 * in 2.4 it kept swapout's vma scan off this vma; but
1334 * in 2.6 the LRU scan won't even find its pages, so this
1335 * flag means no more than count its pages in reserved_vm,
1336 * and omit it from core dump, even when VM_IO turned off.
1337 * VM_PFNMAP tells the core MM that the base pages are just
1338 * raw PFN mappings, and do not have a "struct page" associated
1341 * There's a horrible special case to handle copy-on-write
1342 * behaviour that some programs depend on. We mark the "original"
1343 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1345 if (is_cow_mapping(vma
->vm_flags
)) {
1346 if (addr
!= vma
->vm_start
|| end
!= vma
->vm_end
)
1348 vma
->vm_pgoff
= pfn
;
1351 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1353 BUG_ON(addr
>= end
);
1354 pfn
-= addr
>> PAGE_SHIFT
;
1355 pgd
= pgd_offset(mm
, addr
);
1356 flush_cache_range(vma
, addr
, end
);
1358 next
= pgd_addr_end(addr
, end
);
1359 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1360 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1363 } while (pgd
++, addr
= next
, addr
!= end
);
1366 EXPORT_SYMBOL(remap_pfn_range
);
1368 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1369 unsigned long addr
, unsigned long end
,
1370 pte_fn_t fn
, void *data
)
1374 struct page
*pmd_page
;
1375 spinlock_t
*uninitialized_var(ptl
);
1377 pte
= (mm
== &init_mm
) ?
1378 pte_alloc_kernel(pmd
, addr
) :
1379 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1383 BUG_ON(pmd_huge(*pmd
));
1385 pmd_page
= pmd_page(*pmd
);
1388 err
= fn(pte
, pmd_page
, addr
, data
);
1391 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1394 pte_unmap_unlock(pte
-1, ptl
);
1398 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1399 unsigned long addr
, unsigned long end
,
1400 pte_fn_t fn
, void *data
)
1406 pmd
= pmd_alloc(mm
, pud
, addr
);
1410 next
= pmd_addr_end(addr
, end
);
1411 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1414 } while (pmd
++, addr
= next
, addr
!= end
);
1418 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1419 unsigned long addr
, unsigned long end
,
1420 pte_fn_t fn
, void *data
)
1426 pud
= pud_alloc(mm
, pgd
, addr
);
1430 next
= pud_addr_end(addr
, end
);
1431 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1434 } while (pud
++, addr
= next
, addr
!= end
);
1439 * Scan a region of virtual memory, filling in page tables as necessary
1440 * and calling a provided function on each leaf page table.
1442 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1443 unsigned long size
, pte_fn_t fn
, void *data
)
1447 unsigned long end
= addr
+ size
;
1450 BUG_ON(addr
>= end
);
1451 pgd
= pgd_offset(mm
, addr
);
1453 next
= pgd_addr_end(addr
, end
);
1454 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1457 } while (pgd
++, addr
= next
, addr
!= end
);
1460 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1463 * handle_pte_fault chooses page fault handler according to an entry
1464 * which was read non-atomically. Before making any commitment, on
1465 * those architectures or configurations (e.g. i386 with PAE) which
1466 * might give a mix of unmatched parts, do_swap_page and do_file_page
1467 * must check under lock before unmapping the pte and proceeding
1468 * (but do_wp_page is only called after already making such a check;
1469 * and do_anonymous_page and do_no_page can safely check later on).
1471 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1472 pte_t
*page_table
, pte_t orig_pte
)
1475 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1476 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1477 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1479 same
= pte_same(*page_table
, orig_pte
);
1483 pte_unmap(page_table
);
1488 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1489 * servicing faults for write access. In the normal case, do always want
1490 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1491 * that do not have writing enabled, when used by access_process_vm.
1493 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1495 if (likely(vma
->vm_flags
& VM_WRITE
))
1496 pte
= pte_mkwrite(pte
);
1500 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1503 * If the source page was a PFN mapping, we don't have
1504 * a "struct page" for it. We do a best-effort copy by
1505 * just copying from the original user address. If that
1506 * fails, we just zero-fill it. Live with it.
1508 if (unlikely(!src
)) {
1509 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1510 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1513 * This really shouldn't fail, because the page is there
1514 * in the page tables. But it might just be unreadable,
1515 * in which case we just give up and fill the result with
1518 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1519 memset(kaddr
, 0, PAGE_SIZE
);
1520 kunmap_atomic(kaddr
, KM_USER0
);
1521 flush_dcache_page(dst
);
1525 copy_user_highpage(dst
, src
, va
, vma
);
1529 * This routine handles present pages, when users try to write
1530 * to a shared page. It is done by copying the page to a new address
1531 * and decrementing the shared-page counter for the old page.
1533 * Note that this routine assumes that the protection checks have been
1534 * done by the caller (the low-level page fault routine in most cases).
1535 * Thus we can safely just mark it writable once we've done any necessary
1538 * We also mark the page dirty at this point even though the page will
1539 * change only once the write actually happens. This avoids a few races,
1540 * and potentially makes it more efficient.
1542 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1543 * but allow concurrent faults), with pte both mapped and locked.
1544 * We return with mmap_sem still held, but pte unmapped and unlocked.
1546 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1547 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1548 spinlock_t
*ptl
, pte_t orig_pte
)
1550 struct page
*old_page
, *new_page
;
1552 int reuse
= 0, ret
= 0;
1553 int page_mkwrite
= 0;
1554 struct page
*dirty_page
= NULL
;
1556 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1561 * Take out anonymous pages first, anonymous shared vmas are
1562 * not dirty accountable.
1564 if (PageAnon(old_page
)) {
1565 if (!TestSetPageLocked(old_page
)) {
1566 reuse
= can_share_swap_page(old_page
);
1567 unlock_page(old_page
);
1569 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1570 (VM_WRITE
|VM_SHARED
))) {
1572 * Only catch write-faults on shared writable pages,
1573 * read-only shared pages can get COWed by
1574 * get_user_pages(.write=1, .force=1).
1576 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
1578 * Notify the address space that the page is about to
1579 * become writable so that it can prohibit this or wait
1580 * for the page to get into an appropriate state.
1582 * We do this without the lock held, so that it can
1583 * sleep if it needs to.
1585 page_cache_get(old_page
);
1586 pte_unmap_unlock(page_table
, ptl
);
1588 if (vma
->vm_ops
->page_mkwrite(vma
, old_page
) < 0)
1589 goto unwritable_page
;
1592 * Since we dropped the lock we need to revalidate
1593 * the PTE as someone else may have changed it. If
1594 * they did, we just return, as we can count on the
1595 * MMU to tell us if they didn't also make it writable.
1597 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1599 page_cache_release(old_page
);
1600 if (!pte_same(*page_table
, orig_pte
))
1605 dirty_page
= old_page
;
1606 get_page(dirty_page
);
1611 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1612 entry
= pte_mkyoung(orig_pte
);
1613 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1614 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1)) {
1615 update_mmu_cache(vma
, address
, entry
);
1616 lazy_mmu_prot_update(entry
);
1618 ret
|= VM_FAULT_WRITE
;
1623 * Ok, we need to copy. Oh, well..
1625 page_cache_get(old_page
);
1627 pte_unmap_unlock(page_table
, ptl
);
1629 if (unlikely(anon_vma_prepare(vma
)))
1631 VM_BUG_ON(old_page
== ZERO_PAGE(0));
1632 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
1635 cow_user_page(new_page
, old_page
, address
, vma
);
1638 * Re-check the pte - we dropped the lock
1640 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1641 if (likely(pte_same(*page_table
, orig_pte
))) {
1643 page_remove_rmap(old_page
, vma
);
1644 if (!PageAnon(old_page
)) {
1645 dec_mm_counter(mm
, file_rss
);
1646 inc_mm_counter(mm
, anon_rss
);
1649 inc_mm_counter(mm
, anon_rss
);
1650 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1651 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1652 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1653 lazy_mmu_prot_update(entry
);
1655 * Clear the pte entry and flush it first, before updating the
1656 * pte with the new entry. This will avoid a race condition
1657 * seen in the presence of one thread doing SMC and another
1660 ptep_clear_flush(vma
, address
, page_table
);
1661 set_pte_at(mm
, address
, page_table
, entry
);
1662 update_mmu_cache(vma
, address
, entry
);
1663 lru_cache_add_active(new_page
);
1664 page_add_new_anon_rmap(new_page
, vma
, address
);
1666 /* Free the old page.. */
1667 new_page
= old_page
;
1668 ret
|= VM_FAULT_WRITE
;
1671 page_cache_release(new_page
);
1673 page_cache_release(old_page
);
1675 pte_unmap_unlock(page_table
, ptl
);
1678 * Yes, Virginia, this is actually required to prevent a race
1679 * with clear_page_dirty_for_io() from clearing the page dirty
1680 * bit after it clear all dirty ptes, but before a racing
1681 * do_wp_page installs a dirty pte.
1683 * do_no_page is protected similarly.
1685 wait_on_page_locked(dirty_page
);
1686 set_page_dirty_balance(dirty_page
, page_mkwrite
);
1687 put_page(dirty_page
);
1692 page_cache_release(old_page
);
1693 return VM_FAULT_OOM
;
1696 page_cache_release(old_page
);
1697 return VM_FAULT_SIGBUS
;
1701 * Helper functions for unmap_mapping_range().
1703 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1705 * We have to restart searching the prio_tree whenever we drop the lock,
1706 * since the iterator is only valid while the lock is held, and anyway
1707 * a later vma might be split and reinserted earlier while lock dropped.
1709 * The list of nonlinear vmas could be handled more efficiently, using
1710 * a placeholder, but handle it in the same way until a need is shown.
1711 * It is important to search the prio_tree before nonlinear list: a vma
1712 * may become nonlinear and be shifted from prio_tree to nonlinear list
1713 * while the lock is dropped; but never shifted from list to prio_tree.
1715 * In order to make forward progress despite restarting the search,
1716 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1717 * quickly skip it next time around. Since the prio_tree search only
1718 * shows us those vmas affected by unmapping the range in question, we
1719 * can't efficiently keep all vmas in step with mapping->truncate_count:
1720 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1721 * mapping->truncate_count and vma->vm_truncate_count are protected by
1724 * In order to make forward progress despite repeatedly restarting some
1725 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1726 * and restart from that address when we reach that vma again. It might
1727 * have been split or merged, shrunk or extended, but never shifted: so
1728 * restart_addr remains valid so long as it remains in the vma's range.
1729 * unmap_mapping_range forces truncate_count to leap over page-aligned
1730 * values so we can save vma's restart_addr in its truncate_count field.
1732 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1734 static void reset_vma_truncate_counts(struct address_space
*mapping
)
1736 struct vm_area_struct
*vma
;
1737 struct prio_tree_iter iter
;
1739 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
1740 vma
->vm_truncate_count
= 0;
1741 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
1742 vma
->vm_truncate_count
= 0;
1745 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
1746 unsigned long start_addr
, unsigned long end_addr
,
1747 struct zap_details
*details
)
1749 unsigned long restart_addr
;
1753 * files that support invalidating or truncating portions of the
1754 * file from under mmaped areas must have their ->fault function
1755 * return a locked page (and set VM_FAULT_LOCKED in the return).
1756 * This provides synchronisation against concurrent unmapping here.
1760 restart_addr
= vma
->vm_truncate_count
;
1761 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
1762 start_addr
= restart_addr
;
1763 if (start_addr
>= end_addr
) {
1764 /* Top of vma has been split off since last time */
1765 vma
->vm_truncate_count
= details
->truncate_count
;
1770 restart_addr
= zap_page_range(vma
, start_addr
,
1771 end_addr
- start_addr
, details
);
1772 need_break
= need_resched() ||
1773 need_lockbreak(details
->i_mmap_lock
);
1775 if (restart_addr
>= end_addr
) {
1776 /* We have now completed this vma: mark it so */
1777 vma
->vm_truncate_count
= details
->truncate_count
;
1781 /* Note restart_addr in vma's truncate_count field */
1782 vma
->vm_truncate_count
= restart_addr
;
1787 spin_unlock(details
->i_mmap_lock
);
1789 spin_lock(details
->i_mmap_lock
);
1793 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
1794 struct zap_details
*details
)
1796 struct vm_area_struct
*vma
;
1797 struct prio_tree_iter iter
;
1798 pgoff_t vba
, vea
, zba
, zea
;
1801 vma_prio_tree_foreach(vma
, &iter
, root
,
1802 details
->first_index
, details
->last_index
) {
1803 /* Skip quickly over those we have already dealt with */
1804 if (vma
->vm_truncate_count
== details
->truncate_count
)
1807 vba
= vma
->vm_pgoff
;
1808 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
1809 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1810 zba
= details
->first_index
;
1813 zea
= details
->last_index
;
1817 if (unmap_mapping_range_vma(vma
,
1818 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
1819 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
1825 static inline void unmap_mapping_range_list(struct list_head
*head
,
1826 struct zap_details
*details
)
1828 struct vm_area_struct
*vma
;
1831 * In nonlinear VMAs there is no correspondence between virtual address
1832 * offset and file offset. So we must perform an exhaustive search
1833 * across *all* the pages in each nonlinear VMA, not just the pages
1834 * whose virtual address lies outside the file truncation point.
1837 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
1838 /* Skip quickly over those we have already dealt with */
1839 if (vma
->vm_truncate_count
== details
->truncate_count
)
1841 details
->nonlinear_vma
= vma
;
1842 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
1843 vma
->vm_end
, details
) < 0)
1849 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
1850 * @mapping: the address space containing mmaps to be unmapped.
1851 * @holebegin: byte in first page to unmap, relative to the start of
1852 * the underlying file. This will be rounded down to a PAGE_SIZE
1853 * boundary. Note that this is different from vmtruncate(), which
1854 * must keep the partial page. In contrast, we must get rid of
1856 * @holelen: size of prospective hole in bytes. This will be rounded
1857 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1859 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1860 * but 0 when invalidating pagecache, don't throw away private data.
1862 void unmap_mapping_range(struct address_space
*mapping
,
1863 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
1865 struct zap_details details
;
1866 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
1867 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1869 /* Check for overflow. */
1870 if (sizeof(holelen
) > sizeof(hlen
)) {
1872 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1873 if (holeend
& ~(long long)ULONG_MAX
)
1874 hlen
= ULONG_MAX
- hba
+ 1;
1877 details
.check_mapping
= even_cows
? NULL
: mapping
;
1878 details
.nonlinear_vma
= NULL
;
1879 details
.first_index
= hba
;
1880 details
.last_index
= hba
+ hlen
- 1;
1881 if (details
.last_index
< details
.first_index
)
1882 details
.last_index
= ULONG_MAX
;
1883 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
1885 spin_lock(&mapping
->i_mmap_lock
);
1887 /* Protect against endless unmapping loops */
1888 mapping
->truncate_count
++;
1889 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
1890 if (mapping
->truncate_count
== 0)
1891 reset_vma_truncate_counts(mapping
);
1892 mapping
->truncate_count
++;
1894 details
.truncate_count
= mapping
->truncate_count
;
1896 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
1897 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
1898 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
1899 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
1900 spin_unlock(&mapping
->i_mmap_lock
);
1902 EXPORT_SYMBOL(unmap_mapping_range
);
1905 * vmtruncate - unmap mappings "freed" by truncate() syscall
1906 * @inode: inode of the file used
1907 * @offset: file offset to start truncating
1909 * NOTE! We have to be ready to update the memory sharing
1910 * between the file and the memory map for a potential last
1911 * incomplete page. Ugly, but necessary.
1913 int vmtruncate(struct inode
* inode
, loff_t offset
)
1915 struct address_space
*mapping
= inode
->i_mapping
;
1916 unsigned long limit
;
1918 if (inode
->i_size
< offset
)
1921 * truncation of in-use swapfiles is disallowed - it would cause
1922 * subsequent swapout to scribble on the now-freed blocks.
1924 if (IS_SWAPFILE(inode
))
1926 i_size_write(inode
, offset
);
1929 * unmap_mapping_range is called twice, first simply for efficiency
1930 * so that truncate_inode_pages does fewer single-page unmaps. However
1931 * after this first call, and before truncate_inode_pages finishes,
1932 * it is possible for private pages to be COWed, which remain after
1933 * truncate_inode_pages finishes, hence the second unmap_mapping_range
1934 * call must be made for correctness.
1936 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
1937 truncate_inode_pages(mapping
, offset
);
1938 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
1942 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
1943 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
1945 if (offset
> inode
->i_sb
->s_maxbytes
)
1947 i_size_write(inode
, offset
);
1950 if (inode
->i_op
&& inode
->i_op
->truncate
)
1951 inode
->i_op
->truncate(inode
);
1954 send_sig(SIGXFSZ
, current
, 0);
1960 EXPORT_SYMBOL(vmtruncate
);
1962 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
1964 struct address_space
*mapping
= inode
->i_mapping
;
1967 * If the underlying filesystem is not going to provide
1968 * a way to truncate a range of blocks (punch a hole) -
1969 * we should return failure right now.
1971 if (!inode
->i_op
|| !inode
->i_op
->truncate_range
)
1974 mutex_lock(&inode
->i_mutex
);
1975 down_write(&inode
->i_alloc_sem
);
1976 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
1977 truncate_inode_pages_range(mapping
, offset
, end
);
1978 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
1979 inode
->i_op
->truncate_range(inode
, offset
, end
);
1980 up_write(&inode
->i_alloc_sem
);
1981 mutex_unlock(&inode
->i_mutex
);
1987 * swapin_readahead - swap in pages in hope we need them soon
1988 * @entry: swap entry of this memory
1989 * @addr: address to start
1990 * @vma: user vma this addresses belong to
1992 * Primitive swap readahead code. We simply read an aligned block of
1993 * (1 << page_cluster) entries in the swap area. This method is chosen
1994 * because it doesn't cost us any seek time. We also make sure to queue
1995 * the 'original' request together with the readahead ones...
1997 * This has been extended to use the NUMA policies from the mm triggering
2000 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
2002 void swapin_readahead(swp_entry_t entry
, unsigned long addr
,struct vm_area_struct
*vma
)
2005 struct vm_area_struct
*next_vma
= vma
? vma
->vm_next
: NULL
;
2008 struct page
*new_page
;
2009 unsigned long offset
;
2012 * Get the number of handles we should do readahead io to.
2014 num
= valid_swaphandles(entry
, &offset
);
2015 for (i
= 0; i
< num
; offset
++, i
++) {
2016 /* Ok, do the async read-ahead now */
2017 new_page
= read_swap_cache_async(swp_entry(swp_type(entry
),
2018 offset
), vma
, addr
);
2021 page_cache_release(new_page
);
2024 * Find the next applicable VMA for the NUMA policy.
2030 if (addr
>= vma
->vm_end
) {
2032 next_vma
= vma
? vma
->vm_next
: NULL
;
2034 if (vma
&& addr
< vma
->vm_start
)
2037 if (next_vma
&& addr
>= next_vma
->vm_start
) {
2039 next_vma
= vma
->vm_next
;
2044 lru_add_drain(); /* Push any new pages onto the LRU now */
2048 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2049 * but allow concurrent faults), and pte mapped but not yet locked.
2050 * We return with mmap_sem still held, but pte unmapped and unlocked.
2052 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2053 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2054 int write_access
, pte_t orig_pte
)
2062 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2065 entry
= pte_to_swp_entry(orig_pte
);
2066 if (is_migration_entry(entry
)) {
2067 migration_entry_wait(mm
, pmd
, address
);
2070 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2071 page
= lookup_swap_cache(entry
);
2073 grab_swap_token(); /* Contend for token _before_ read-in */
2074 swapin_readahead(entry
, address
, vma
);
2075 page
= read_swap_cache_async(entry
, vma
, address
);
2078 * Back out if somebody else faulted in this pte
2079 * while we released the pte lock.
2081 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2082 if (likely(pte_same(*page_table
, orig_pte
)))
2084 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2088 /* Had to read the page from swap area: Major fault */
2089 ret
= VM_FAULT_MAJOR
;
2090 count_vm_event(PGMAJFAULT
);
2093 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2094 mark_page_accessed(page
);
2098 * Back out if somebody else already faulted in this pte.
2100 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2101 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2104 if (unlikely(!PageUptodate(page
))) {
2105 ret
= VM_FAULT_SIGBUS
;
2109 /* The page isn't present yet, go ahead with the fault. */
2111 inc_mm_counter(mm
, anon_rss
);
2112 pte
= mk_pte(page
, vma
->vm_page_prot
);
2113 if (write_access
&& can_share_swap_page(page
)) {
2114 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2118 flush_icache_page(vma
, page
);
2119 set_pte_at(mm
, address
, page_table
, pte
);
2120 page_add_anon_rmap(page
, vma
, address
);
2124 remove_exclusive_swap_page(page
);
2128 /* XXX: We could OR the do_wp_page code with this one? */
2129 if (do_wp_page(mm
, vma
, address
,
2130 page_table
, pmd
, ptl
, pte
) & VM_FAULT_OOM
)
2135 /* No need to invalidate - it was non-present before */
2136 update_mmu_cache(vma
, address
, pte
);
2138 pte_unmap_unlock(page_table
, ptl
);
2142 pte_unmap_unlock(page_table
, ptl
);
2144 page_cache_release(page
);
2149 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2150 * but allow concurrent faults), and pte mapped but not yet locked.
2151 * We return with mmap_sem still held, but pte unmapped and unlocked.
2153 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2154 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2161 /* Allocate our own private page. */
2162 pte_unmap(page_table
);
2164 if (unlikely(anon_vma_prepare(vma
)))
2166 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2170 entry
= mk_pte(page
, vma
->vm_page_prot
);
2171 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2173 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2174 if (!pte_none(*page_table
))
2176 inc_mm_counter(mm
, anon_rss
);
2177 lru_cache_add_active(page
);
2178 page_add_new_anon_rmap(page
, vma
, address
);
2179 set_pte_at(mm
, address
, page_table
, entry
);
2181 /* No need to invalidate - it was non-present before */
2182 update_mmu_cache(vma
, address
, entry
);
2183 lazy_mmu_prot_update(entry
);
2185 pte_unmap_unlock(page_table
, ptl
);
2188 page_cache_release(page
);
2191 return VM_FAULT_OOM
;
2195 * __do_fault() tries to create a new page mapping. It aggressively
2196 * tries to share with existing pages, but makes a separate copy if
2197 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2198 * the next page fault.
2200 * As this is called only for pages that do not currently exist, we
2201 * do not need to flush old virtual caches or the TLB.
2203 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2204 * but allow concurrent faults), and pte neither mapped nor locked.
2205 * We return with mmap_sem still held, but pte unmapped and unlocked.
2207 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2208 unsigned long address
, pmd_t
*pmd
,
2209 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2216 struct page
*dirty_page
= NULL
;
2217 struct vm_fault vmf
;
2219 int page_mkwrite
= 0;
2221 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2226 BUG_ON(vma
->vm_flags
& VM_PFNMAP
);
2228 if (likely(vma
->vm_ops
->fault
)) {
2229 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2230 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2233 /* Legacy ->nopage path */
2235 vmf
.page
= vma
->vm_ops
->nopage(vma
, address
& PAGE_MASK
, &ret
);
2236 /* no page was available -- either SIGBUS or OOM */
2237 if (unlikely(vmf
.page
== NOPAGE_SIGBUS
))
2238 return VM_FAULT_SIGBUS
;
2239 else if (unlikely(vmf
.page
== NOPAGE_OOM
))
2240 return VM_FAULT_OOM
;
2244 * For consistency in subsequent calls, make the faulted page always
2247 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2248 lock_page(vmf
.page
);
2250 VM_BUG_ON(!PageLocked(vmf
.page
));
2253 * Should we do an early C-O-W break?
2256 if (flags
& FAULT_FLAG_WRITE
) {
2257 if (!(vma
->vm_flags
& VM_SHARED
)) {
2259 if (unlikely(anon_vma_prepare(vma
))) {
2263 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2269 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2272 * If the page will be shareable, see if the backing
2273 * address space wants to know that the page is about
2274 * to become writable
2276 if (vma
->vm_ops
->page_mkwrite
) {
2278 if (vma
->vm_ops
->page_mkwrite(vma
, page
) < 0) {
2279 ret
= VM_FAULT_SIGBUS
;
2280 anon
= 1; /* no anon but release vmf.page */
2285 * XXX: this is not quite right (racy vs
2286 * invalidate) to unlock and relock the page
2287 * like this, however a better fix requires
2288 * reworking page_mkwrite locking API, which
2289 * is better done later.
2291 if (!page
->mapping
) {
2293 anon
= 1; /* no anon but release vmf.page */
2302 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2305 * This silly early PAGE_DIRTY setting removes a race
2306 * due to the bad i386 page protection. But it's valid
2307 * for other architectures too.
2309 * Note that if write_access is true, we either now have
2310 * an exclusive copy of the page, or this is a shared mapping,
2311 * so we can make it writable and dirty to avoid having to
2312 * handle that later.
2314 /* Only go through if we didn't race with anybody else... */
2315 if (likely(pte_same(*page_table
, orig_pte
))) {
2316 flush_icache_page(vma
, page
);
2317 entry
= mk_pte(page
, vma
->vm_page_prot
);
2318 if (flags
& FAULT_FLAG_WRITE
)
2319 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2320 set_pte_at(mm
, address
, page_table
, entry
);
2322 inc_mm_counter(mm
, anon_rss
);
2323 lru_cache_add_active(page
);
2324 page_add_new_anon_rmap(page
, vma
, address
);
2326 inc_mm_counter(mm
, file_rss
);
2327 page_add_file_rmap(page
);
2328 if (flags
& FAULT_FLAG_WRITE
) {
2330 get_page(dirty_page
);
2334 /* no need to invalidate: a not-present page won't be cached */
2335 update_mmu_cache(vma
, address
, entry
);
2336 lazy_mmu_prot_update(entry
);
2339 page_cache_release(page
);
2341 anon
= 1; /* no anon but release faulted_page */
2344 pte_unmap_unlock(page_table
, ptl
);
2347 unlock_page(vmf
.page
);
2350 page_cache_release(vmf
.page
);
2351 else if (dirty_page
) {
2352 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2353 put_page(dirty_page
);
2359 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2360 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2361 int write_access
, pte_t orig_pte
)
2363 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2364 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2365 unsigned int flags
= (write_access
? FAULT_FLAG_WRITE
: 0);
2367 pte_unmap(page_table
);
2368 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2373 * do_no_pfn() tries to create a new page mapping for a page without
2374 * a struct_page backing it
2376 * As this is called only for pages that do not currently exist, we
2377 * do not need to flush old virtual caches or the TLB.
2379 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2380 * but allow concurrent faults), and pte mapped but not yet locked.
2381 * We return with mmap_sem still held, but pte unmapped and unlocked.
2383 * It is expected that the ->nopfn handler always returns the same pfn
2384 * for a given virtual mapping.
2386 * Mark this `noinline' to prevent it from bloating the main pagefault code.
2388 static noinline
int do_no_pfn(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2389 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2396 pte_unmap(page_table
);
2397 BUG_ON(!(vma
->vm_flags
& VM_PFNMAP
));
2398 BUG_ON(is_cow_mapping(vma
->vm_flags
));
2400 pfn
= vma
->vm_ops
->nopfn(vma
, address
& PAGE_MASK
);
2401 if (unlikely(pfn
== NOPFN_OOM
))
2402 return VM_FAULT_OOM
;
2403 else if (unlikely(pfn
== NOPFN_SIGBUS
))
2404 return VM_FAULT_SIGBUS
;
2405 else if (unlikely(pfn
== NOPFN_REFAULT
))
2408 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2410 /* Only go through if we didn't race with anybody else... */
2411 if (pte_none(*page_table
)) {
2412 entry
= pfn_pte(pfn
, vma
->vm_page_prot
);
2414 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2415 set_pte_at(mm
, address
, page_table
, entry
);
2417 pte_unmap_unlock(page_table
, ptl
);
2422 * Fault of a previously existing named mapping. Repopulate the pte
2423 * from the encoded file_pte if possible. This enables swappable
2426 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2427 * but allow concurrent faults), and pte mapped but not yet locked.
2428 * We return with mmap_sem still held, but pte unmapped and unlocked.
2430 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2431 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2432 int write_access
, pte_t orig_pte
)
2434 unsigned int flags
= FAULT_FLAG_NONLINEAR
|
2435 (write_access
? FAULT_FLAG_WRITE
: 0);
2438 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2441 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
) ||
2442 !(vma
->vm_flags
& VM_CAN_NONLINEAR
))) {
2444 * Page table corrupted: show pte and kill process.
2446 print_bad_pte(vma
, orig_pte
, address
);
2447 return VM_FAULT_OOM
;
2450 pgoff
= pte_to_pgoff(orig_pte
);
2451 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2455 * These routines also need to handle stuff like marking pages dirty
2456 * and/or accessed for architectures that don't do it in hardware (most
2457 * RISC architectures). The early dirtying is also good on the i386.
2459 * There is also a hook called "update_mmu_cache()" that architectures
2460 * with external mmu caches can use to update those (ie the Sparc or
2461 * PowerPC hashed page tables that act as extended TLBs).
2463 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2464 * but allow concurrent faults), and pte mapped but not yet locked.
2465 * We return with mmap_sem still held, but pte unmapped and unlocked.
2467 static inline int handle_pte_fault(struct mm_struct
*mm
,
2468 struct vm_area_struct
*vma
, unsigned long address
,
2469 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
2475 if (!pte_present(entry
)) {
2476 if (pte_none(entry
)) {
2478 if (vma
->vm_ops
->fault
|| vma
->vm_ops
->nopage
)
2479 return do_linear_fault(mm
, vma
, address
,
2480 pte
, pmd
, write_access
, entry
);
2481 if (unlikely(vma
->vm_ops
->nopfn
))
2482 return do_no_pfn(mm
, vma
, address
, pte
,
2485 return do_anonymous_page(mm
, vma
, address
,
2486 pte
, pmd
, write_access
);
2488 if (pte_file(entry
))
2489 return do_nonlinear_fault(mm
, vma
, address
,
2490 pte
, pmd
, write_access
, entry
);
2491 return do_swap_page(mm
, vma
, address
,
2492 pte
, pmd
, write_access
, entry
);
2495 ptl
= pte_lockptr(mm
, pmd
);
2497 if (unlikely(!pte_same(*pte
, entry
)))
2500 if (!pte_write(entry
))
2501 return do_wp_page(mm
, vma
, address
,
2502 pte
, pmd
, ptl
, entry
);
2503 entry
= pte_mkdirty(entry
);
2505 entry
= pte_mkyoung(entry
);
2506 if (ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
)) {
2507 update_mmu_cache(vma
, address
, entry
);
2508 lazy_mmu_prot_update(entry
);
2511 * This is needed only for protection faults but the arch code
2512 * is not yet telling us if this is a protection fault or not.
2513 * This still avoids useless tlb flushes for .text page faults
2517 flush_tlb_page(vma
, address
);
2520 pte_unmap_unlock(pte
, ptl
);
2525 * By the time we get here, we already hold the mm semaphore
2527 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2528 unsigned long address
, int write_access
)
2535 __set_current_state(TASK_RUNNING
);
2537 count_vm_event(PGFAULT
);
2539 if (unlikely(is_vm_hugetlb_page(vma
)))
2540 return hugetlb_fault(mm
, vma
, address
, write_access
);
2542 pgd
= pgd_offset(mm
, address
);
2543 pud
= pud_alloc(mm
, pgd
, address
);
2545 return VM_FAULT_OOM
;
2546 pmd
= pmd_alloc(mm
, pud
, address
);
2548 return VM_FAULT_OOM
;
2549 pte
= pte_alloc_map(mm
, pmd
, address
);
2551 return VM_FAULT_OOM
;
2553 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2556 #ifndef __PAGETABLE_PUD_FOLDED
2558 * Allocate page upper directory.
2559 * We've already handled the fast-path in-line.
2561 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2563 pud_t
*new = pud_alloc_one(mm
, address
);
2567 spin_lock(&mm
->page_table_lock
);
2568 if (pgd_present(*pgd
)) /* Another has populated it */
2571 pgd_populate(mm
, pgd
, new);
2572 spin_unlock(&mm
->page_table_lock
);
2575 #endif /* __PAGETABLE_PUD_FOLDED */
2577 #ifndef __PAGETABLE_PMD_FOLDED
2579 * Allocate page middle directory.
2580 * We've already handled the fast-path in-line.
2582 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2584 pmd_t
*new = pmd_alloc_one(mm
, address
);
2588 spin_lock(&mm
->page_table_lock
);
2589 #ifndef __ARCH_HAS_4LEVEL_HACK
2590 if (pud_present(*pud
)) /* Another has populated it */
2593 pud_populate(mm
, pud
, new);
2595 if (pgd_present(*pud
)) /* Another has populated it */
2598 pgd_populate(mm
, pud
, new);
2599 #endif /* __ARCH_HAS_4LEVEL_HACK */
2600 spin_unlock(&mm
->page_table_lock
);
2603 #endif /* __PAGETABLE_PMD_FOLDED */
2605 int make_pages_present(unsigned long addr
, unsigned long end
)
2607 int ret
, len
, write
;
2608 struct vm_area_struct
* vma
;
2610 vma
= find_vma(current
->mm
, addr
);
2613 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2614 BUG_ON(addr
>= end
);
2615 BUG_ON(end
> vma
->vm_end
);
2616 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
2617 ret
= get_user_pages(current
, current
->mm
, addr
,
2618 len
, write
, 0, NULL
, NULL
);
2621 return ret
== len
? 0 : -1;
2625 * Map a vmalloc()-space virtual address to the physical page.
2627 struct page
* vmalloc_to_page(void * vmalloc_addr
)
2629 unsigned long addr
= (unsigned long) vmalloc_addr
;
2630 struct page
*page
= NULL
;
2631 pgd_t
*pgd
= pgd_offset_k(addr
);
2636 if (!pgd_none(*pgd
)) {
2637 pud
= pud_offset(pgd
, addr
);
2638 if (!pud_none(*pud
)) {
2639 pmd
= pmd_offset(pud
, addr
);
2640 if (!pmd_none(*pmd
)) {
2641 ptep
= pte_offset_map(pmd
, addr
);
2643 if (pte_present(pte
))
2644 page
= pte_page(pte
);
2652 EXPORT_SYMBOL(vmalloc_to_page
);
2655 * Map a vmalloc()-space virtual address to the physical page frame number.
2657 unsigned long vmalloc_to_pfn(void * vmalloc_addr
)
2659 return page_to_pfn(vmalloc_to_page(vmalloc_addr
));
2662 EXPORT_SYMBOL(vmalloc_to_pfn
);
2664 #if !defined(__HAVE_ARCH_GATE_AREA)
2666 #if defined(AT_SYSINFO_EHDR)
2667 static struct vm_area_struct gate_vma
;
2669 static int __init
gate_vma_init(void)
2671 gate_vma
.vm_mm
= NULL
;
2672 gate_vma
.vm_start
= FIXADDR_USER_START
;
2673 gate_vma
.vm_end
= FIXADDR_USER_END
;
2674 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
2675 gate_vma
.vm_page_prot
= __P101
;
2677 * Make sure the vDSO gets into every core dump.
2678 * Dumping its contents makes post-mortem fully interpretable later
2679 * without matching up the same kernel and hardware config to see
2680 * what PC values meant.
2682 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
2685 __initcall(gate_vma_init
);
2688 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2690 #ifdef AT_SYSINFO_EHDR
2697 int in_gate_area_no_task(unsigned long addr
)
2699 #ifdef AT_SYSINFO_EHDR
2700 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2706 #endif /* __HAVE_ARCH_GATE_AREA */
2709 * Access another process' address space.
2710 * Source/target buffer must be kernel space,
2711 * Do not walk the page table directly, use get_user_pages
2713 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
2715 struct mm_struct
*mm
;
2716 struct vm_area_struct
*vma
;
2718 void *old_buf
= buf
;
2720 mm
= get_task_mm(tsk
);
2724 down_read(&mm
->mmap_sem
);
2725 /* ignore errors, just check how much was sucessfully transfered */
2727 int bytes
, ret
, offset
;
2730 ret
= get_user_pages(tsk
, mm
, addr
, 1,
2731 write
, 1, &page
, &vma
);
2736 offset
= addr
& (PAGE_SIZE
-1);
2737 if (bytes
> PAGE_SIZE
-offset
)
2738 bytes
= PAGE_SIZE
-offset
;
2742 copy_to_user_page(vma
, page
, addr
,
2743 maddr
+ offset
, buf
, bytes
);
2744 set_page_dirty_lock(page
);
2746 copy_from_user_page(vma
, page
, addr
,
2747 buf
, maddr
+ offset
, bytes
);
2750 page_cache_release(page
);
2755 up_read(&mm
->mmap_sem
);
2758 return buf
- old_buf
;
2760 EXPORT_SYMBOL_GPL(access_process_vm
);