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>
53 #include <linux/memcontrol.h>
54 #include <linux/mmu_notifier.h>
56 #include <asm/pgalloc.h>
57 #include <asm/uaccess.h>
59 #include <asm/tlbflush.h>
60 #include <asm/pgtable.h>
62 #include <linux/swapops.h>
63 #include <linux/elf.h>
69 #ifndef CONFIG_NEED_MULTIPLE_NODES
70 /* use the per-pgdat data instead for discontigmem - mbligh */
71 unsigned long max_mapnr
;
74 EXPORT_SYMBOL(max_mapnr
);
75 EXPORT_SYMBOL(mem_map
);
78 unsigned long num_physpages
;
80 * A number of key systems in x86 including ioremap() rely on the assumption
81 * that high_memory defines the upper bound on direct map memory, then end
82 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
83 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
88 EXPORT_SYMBOL(num_physpages
);
89 EXPORT_SYMBOL(high_memory
);
92 * Randomize the address space (stacks, mmaps, brk, etc.).
94 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
95 * as ancient (libc5 based) binaries can segfault. )
97 int randomize_va_space __read_mostly
=
98 #ifdef CONFIG_COMPAT_BRK
104 static int __init
disable_randmaps(char *s
)
106 randomize_va_space
= 0;
109 __setup("norandmaps", disable_randmaps
);
113 * If a p?d_bad entry is found while walking page tables, report
114 * the error, before resetting entry to p?d_none. Usually (but
115 * very seldom) called out from the p?d_none_or_clear_bad macros.
118 void pgd_clear_bad(pgd_t
*pgd
)
124 void pud_clear_bad(pud_t
*pud
)
130 void pmd_clear_bad(pmd_t
*pmd
)
137 * Note: this doesn't free the actual pages themselves. That
138 * has been handled earlier when unmapping all the memory regions.
140 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
)
142 pgtable_t token
= pmd_pgtable(*pmd
);
144 pte_free_tlb(tlb
, token
);
148 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
149 unsigned long addr
, unsigned long end
,
150 unsigned long floor
, unsigned long ceiling
)
157 pmd
= pmd_offset(pud
, addr
);
159 next
= pmd_addr_end(addr
, end
);
160 if (pmd_none_or_clear_bad(pmd
))
162 free_pte_range(tlb
, pmd
);
163 } while (pmd
++, addr
= next
, addr
!= end
);
173 if (end
- 1 > ceiling
- 1)
176 pmd
= pmd_offset(pud
, start
);
178 pmd_free_tlb(tlb
, pmd
);
181 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
182 unsigned long addr
, unsigned long end
,
183 unsigned long floor
, unsigned long ceiling
)
190 pud
= pud_offset(pgd
, addr
);
192 next
= pud_addr_end(addr
, end
);
193 if (pud_none_or_clear_bad(pud
))
195 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
196 } while (pud
++, addr
= next
, addr
!= end
);
202 ceiling
&= PGDIR_MASK
;
206 if (end
- 1 > ceiling
- 1)
209 pud
= pud_offset(pgd
, start
);
211 pud_free_tlb(tlb
, pud
);
215 * This function frees user-level page tables of a process.
217 * Must be called with pagetable lock held.
219 void free_pgd_range(struct mmu_gather
*tlb
,
220 unsigned long addr
, unsigned long end
,
221 unsigned long floor
, unsigned long ceiling
)
228 * The next few lines have given us lots of grief...
230 * Why are we testing PMD* at this top level? Because often
231 * there will be no work to do at all, and we'd prefer not to
232 * go all the way down to the bottom just to discover that.
234 * Why all these "- 1"s? Because 0 represents both the bottom
235 * of the address space and the top of it (using -1 for the
236 * top wouldn't help much: the masks would do the wrong thing).
237 * The rule is that addr 0 and floor 0 refer to the bottom of
238 * the address space, but end 0 and ceiling 0 refer to the top
239 * Comparisons need to use "end - 1" and "ceiling - 1" (though
240 * that end 0 case should be mythical).
242 * Wherever addr is brought up or ceiling brought down, we must
243 * be careful to reject "the opposite 0" before it confuses the
244 * subsequent tests. But what about where end is brought down
245 * by PMD_SIZE below? no, end can't go down to 0 there.
247 * Whereas we round start (addr) and ceiling down, by different
248 * masks at different levels, in order to test whether a table
249 * now has no other vmas using it, so can be freed, we don't
250 * bother to round floor or end up - the tests don't need that.
264 if (end
- 1 > ceiling
- 1)
270 pgd
= pgd_offset(tlb
->mm
, addr
);
272 next
= pgd_addr_end(addr
, end
);
273 if (pgd_none_or_clear_bad(pgd
))
275 free_pud_range(tlb
, pgd
, addr
, next
, floor
, ceiling
);
276 } while (pgd
++, addr
= next
, addr
!= end
);
279 void free_pgtables(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
280 unsigned long floor
, unsigned long ceiling
)
283 struct vm_area_struct
*next
= vma
->vm_next
;
284 unsigned long addr
= vma
->vm_start
;
287 * Hide vma from rmap and vmtruncate before freeing pgtables
289 anon_vma_unlink(vma
);
290 unlink_file_vma(vma
);
292 if (is_vm_hugetlb_page(vma
)) {
293 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
294 floor
, next
? next
->vm_start
: ceiling
);
297 * Optimization: gather nearby vmas into one call down
299 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
300 && !is_vm_hugetlb_page(next
)) {
303 anon_vma_unlink(vma
);
304 unlink_file_vma(vma
);
306 free_pgd_range(tlb
, addr
, vma
->vm_end
,
307 floor
, next
? next
->vm_start
: ceiling
);
313 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
315 pgtable_t
new = pte_alloc_one(mm
, address
);
320 * Ensure all pte setup (eg. pte page lock and page clearing) are
321 * visible before the pte is made visible to other CPUs by being
322 * put into page tables.
324 * The other side of the story is the pointer chasing in the page
325 * table walking code (when walking the page table without locking;
326 * ie. most of the time). Fortunately, these data accesses consist
327 * of a chain of data-dependent loads, meaning most CPUs (alpha
328 * being the notable exception) will already guarantee loads are
329 * seen in-order. See the alpha page table accessors for the
330 * smp_read_barrier_depends() barriers in page table walking code.
332 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
334 spin_lock(&mm
->page_table_lock
);
335 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
337 pmd_populate(mm
, pmd
, new);
340 spin_unlock(&mm
->page_table_lock
);
346 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
348 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
352 smp_wmb(); /* See comment in __pte_alloc */
354 spin_lock(&init_mm
.page_table_lock
);
355 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
356 pmd_populate_kernel(&init_mm
, pmd
, new);
359 spin_unlock(&init_mm
.page_table_lock
);
361 pte_free_kernel(&init_mm
, new);
365 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
368 add_mm_counter(mm
, file_rss
, file_rss
);
370 add_mm_counter(mm
, anon_rss
, anon_rss
);
374 * This function is called to print an error when a bad pte
375 * is found. For example, we might have a PFN-mapped pte in
376 * a region that doesn't allow it.
378 * The calling function must still handle the error.
380 static void print_bad_pte(struct vm_area_struct
*vma
, pte_t pte
,
383 printk(KERN_ERR
"Bad pte = %08llx, process = %s, "
384 "vm_flags = %lx, vaddr = %lx\n",
385 (long long)pte_val(pte
),
386 (vma
->vm_mm
== current
->mm
? current
->comm
: "???"),
387 vma
->vm_flags
, vaddr
);
391 static inline int is_cow_mapping(unsigned int flags
)
393 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
397 * vm_normal_page -- This function gets the "struct page" associated with a pte.
399 * "Special" mappings do not wish to be associated with a "struct page" (either
400 * it doesn't exist, or it exists but they don't want to touch it). In this
401 * case, NULL is returned here. "Normal" mappings do have a struct page.
403 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
404 * pte bit, in which case this function is trivial. Secondly, an architecture
405 * may not have a spare pte bit, which requires a more complicated scheme,
408 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
409 * special mapping (even if there are underlying and valid "struct pages").
410 * COWed pages of a VM_PFNMAP are always normal.
412 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
413 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
414 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
415 * mapping will always honor the rule
417 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
419 * And for normal mappings this is false.
421 * This restricts such mappings to be a linear translation from virtual address
422 * to pfn. To get around this restriction, we allow arbitrary mappings so long
423 * as the vma is not a COW mapping; in that case, we know that all ptes are
424 * special (because none can have been COWed).
427 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
429 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
430 * page" backing, however the difference is that _all_ pages with a struct
431 * page (that is, those where pfn_valid is true) are refcounted and considered
432 * normal pages by the VM. The disadvantage is that pages are refcounted
433 * (which can be slower and simply not an option for some PFNMAP users). The
434 * advantage is that we don't have to follow the strict linearity rule of
435 * PFNMAP mappings in order to support COWable mappings.
438 #ifdef __HAVE_ARCH_PTE_SPECIAL
439 # define HAVE_PTE_SPECIAL 1
441 # define HAVE_PTE_SPECIAL 0
443 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
448 if (HAVE_PTE_SPECIAL
) {
449 if (likely(!pte_special(pte
))) {
450 VM_BUG_ON(!pfn_valid(pte_pfn(pte
)));
451 return pte_page(pte
);
453 VM_BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
)));
457 /* !HAVE_PTE_SPECIAL case follows: */
461 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
462 if (vma
->vm_flags
& VM_MIXEDMAP
) {
468 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
469 if (pfn
== vma
->vm_pgoff
+ off
)
471 if (!is_cow_mapping(vma
->vm_flags
))
476 VM_BUG_ON(!pfn_valid(pfn
));
479 * NOTE! We still have PageReserved() pages in the page tables.
481 * eg. VDSO mappings can cause them to exist.
484 return pfn_to_page(pfn
);
488 * copy one vm_area from one task to the other. Assumes the page tables
489 * already present in the new task to be cleared in the whole range
490 * covered by this vma.
494 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
495 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
496 unsigned long addr
, int *rss
)
498 unsigned long vm_flags
= vma
->vm_flags
;
499 pte_t pte
= *src_pte
;
502 /* pte contains position in swap or file, so copy. */
503 if (unlikely(!pte_present(pte
))) {
504 if (!pte_file(pte
)) {
505 swp_entry_t entry
= pte_to_swp_entry(pte
);
507 swap_duplicate(entry
);
508 /* make sure dst_mm is on swapoff's mmlist. */
509 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
510 spin_lock(&mmlist_lock
);
511 if (list_empty(&dst_mm
->mmlist
))
512 list_add(&dst_mm
->mmlist
,
514 spin_unlock(&mmlist_lock
);
516 if (is_write_migration_entry(entry
) &&
517 is_cow_mapping(vm_flags
)) {
519 * COW mappings require pages in both parent
520 * and child to be set to read.
522 make_migration_entry_read(&entry
);
523 pte
= swp_entry_to_pte(entry
);
524 set_pte_at(src_mm
, addr
, src_pte
, pte
);
531 * If it's a COW mapping, write protect it both
532 * in the parent and the child
534 if (is_cow_mapping(vm_flags
)) {
535 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
536 pte
= pte_wrprotect(pte
);
540 * If it's a shared mapping, mark it clean in
543 if (vm_flags
& VM_SHARED
)
544 pte
= pte_mkclean(pte
);
545 pte
= pte_mkold(pte
);
547 page
= vm_normal_page(vma
, addr
, pte
);
550 page_dup_rmap(page
, vma
, addr
);
551 rss
[!!PageAnon(page
)]++;
555 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
558 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
559 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
560 unsigned long addr
, unsigned long end
)
562 pte_t
*src_pte
, *dst_pte
;
563 spinlock_t
*src_ptl
, *dst_ptl
;
569 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
572 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
573 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
574 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
575 arch_enter_lazy_mmu_mode();
579 * We are holding two locks at this point - either of them
580 * could generate latencies in another task on another CPU.
582 if (progress
>= 32) {
584 if (need_resched() ||
585 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
588 if (pte_none(*src_pte
)) {
592 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
594 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
596 arch_leave_lazy_mmu_mode();
597 spin_unlock(src_ptl
);
598 pte_unmap_nested(src_pte
- 1);
599 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
600 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
607 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
608 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
609 unsigned long addr
, unsigned long end
)
611 pmd_t
*src_pmd
, *dst_pmd
;
614 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
617 src_pmd
= pmd_offset(src_pud
, addr
);
619 next
= pmd_addr_end(addr
, end
);
620 if (pmd_none_or_clear_bad(src_pmd
))
622 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
625 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
629 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
630 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
631 unsigned long addr
, unsigned long end
)
633 pud_t
*src_pud
, *dst_pud
;
636 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
639 src_pud
= pud_offset(src_pgd
, addr
);
641 next
= pud_addr_end(addr
, end
);
642 if (pud_none_or_clear_bad(src_pud
))
644 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
647 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
651 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
652 struct vm_area_struct
*vma
)
654 pgd_t
*src_pgd
, *dst_pgd
;
656 unsigned long addr
= vma
->vm_start
;
657 unsigned long end
= vma
->vm_end
;
661 * Don't copy ptes where a page fault will fill them correctly.
662 * Fork becomes much lighter when there are big shared or private
663 * readonly mappings. The tradeoff is that copy_page_range is more
664 * efficient than faulting.
666 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
671 if (is_vm_hugetlb_page(vma
))
672 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
675 * We need to invalidate the secondary MMU mappings only when
676 * there could be a permission downgrade on the ptes of the
677 * parent mm. And a permission downgrade will only happen if
678 * is_cow_mapping() returns true.
680 if (is_cow_mapping(vma
->vm_flags
))
681 mmu_notifier_invalidate_range_start(src_mm
, addr
, end
);
684 dst_pgd
= pgd_offset(dst_mm
, addr
);
685 src_pgd
= pgd_offset(src_mm
, addr
);
687 next
= pgd_addr_end(addr
, end
);
688 if (pgd_none_or_clear_bad(src_pgd
))
690 if (unlikely(copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
695 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
697 if (is_cow_mapping(vma
->vm_flags
))
698 mmu_notifier_invalidate_range_end(src_mm
,
703 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
704 struct vm_area_struct
*vma
, pmd_t
*pmd
,
705 unsigned long addr
, unsigned long end
,
706 long *zap_work
, struct zap_details
*details
)
708 struct mm_struct
*mm
= tlb
->mm
;
714 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
715 arch_enter_lazy_mmu_mode();
718 if (pte_none(ptent
)) {
723 (*zap_work
) -= PAGE_SIZE
;
725 if (pte_present(ptent
)) {
728 page
= vm_normal_page(vma
, addr
, ptent
);
729 if (unlikely(details
) && page
) {
731 * unmap_shared_mapping_pages() wants to
732 * invalidate cache without truncating:
733 * unmap shared but keep private pages.
735 if (details
->check_mapping
&&
736 details
->check_mapping
!= page
->mapping
)
739 * Each page->index must be checked when
740 * invalidating or truncating nonlinear.
742 if (details
->nonlinear_vma
&&
743 (page
->index
< details
->first_index
||
744 page
->index
> details
->last_index
))
747 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
749 tlb_remove_tlb_entry(tlb
, pte
, addr
);
752 if (unlikely(details
) && details
->nonlinear_vma
753 && linear_page_index(details
->nonlinear_vma
,
754 addr
) != page
->index
)
755 set_pte_at(mm
, addr
, pte
,
756 pgoff_to_pte(page
->index
));
760 if (pte_dirty(ptent
))
761 set_page_dirty(page
);
762 if (pte_young(ptent
))
763 SetPageReferenced(page
);
766 page_remove_rmap(page
, vma
);
767 tlb_remove_page(tlb
, page
);
771 * If details->check_mapping, we leave swap entries;
772 * if details->nonlinear_vma, we leave file entries.
774 if (unlikely(details
))
776 if (!pte_file(ptent
))
777 free_swap_and_cache(pte_to_swp_entry(ptent
));
778 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
779 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
781 add_mm_rss(mm
, file_rss
, anon_rss
);
782 arch_leave_lazy_mmu_mode();
783 pte_unmap_unlock(pte
- 1, ptl
);
788 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
789 struct vm_area_struct
*vma
, pud_t
*pud
,
790 unsigned long addr
, unsigned long end
,
791 long *zap_work
, struct zap_details
*details
)
796 pmd
= pmd_offset(pud
, addr
);
798 next
= pmd_addr_end(addr
, end
);
799 if (pmd_none_or_clear_bad(pmd
)) {
803 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
805 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
810 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
811 struct vm_area_struct
*vma
, pgd_t
*pgd
,
812 unsigned long addr
, unsigned long end
,
813 long *zap_work
, struct zap_details
*details
)
818 pud
= pud_offset(pgd
, addr
);
820 next
= pud_addr_end(addr
, end
);
821 if (pud_none_or_clear_bad(pud
)) {
825 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
827 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
832 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
833 struct vm_area_struct
*vma
,
834 unsigned long addr
, unsigned long end
,
835 long *zap_work
, struct zap_details
*details
)
840 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
844 tlb_start_vma(tlb
, vma
);
845 pgd
= pgd_offset(vma
->vm_mm
, addr
);
847 next
= pgd_addr_end(addr
, end
);
848 if (pgd_none_or_clear_bad(pgd
)) {
852 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
854 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
855 tlb_end_vma(tlb
, vma
);
860 #ifdef CONFIG_PREEMPT
861 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
863 /* No preempt: go for improved straight-line efficiency */
864 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
868 * unmap_vmas - unmap a range of memory covered by a list of vma's
869 * @tlbp: address of the caller's struct mmu_gather
870 * @vma: the starting vma
871 * @start_addr: virtual address at which to start unmapping
872 * @end_addr: virtual address at which to end unmapping
873 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
874 * @details: details of nonlinear truncation or shared cache invalidation
876 * Returns the end address of the unmapping (restart addr if interrupted).
878 * Unmap all pages in the vma list.
880 * We aim to not hold locks for too long (for scheduling latency reasons).
881 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
882 * return the ending mmu_gather to the caller.
884 * Only addresses between `start' and `end' will be unmapped.
886 * The VMA list must be sorted in ascending virtual address order.
888 * unmap_vmas() assumes that the caller will flush the whole unmapped address
889 * range after unmap_vmas() returns. So the only responsibility here is to
890 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
891 * drops the lock and schedules.
893 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
894 struct vm_area_struct
*vma
, unsigned long start_addr
,
895 unsigned long end_addr
, unsigned long *nr_accounted
,
896 struct zap_details
*details
)
898 long zap_work
= ZAP_BLOCK_SIZE
;
899 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
900 int tlb_start_valid
= 0;
901 unsigned long start
= start_addr
;
902 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
903 int fullmm
= (*tlbp
)->fullmm
;
904 struct mm_struct
*mm
= vma
->vm_mm
;
906 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
907 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
910 start
= max(vma
->vm_start
, start_addr
);
911 if (start
>= vma
->vm_end
)
913 end
= min(vma
->vm_end
, end_addr
);
914 if (end
<= vma
->vm_start
)
917 if (vma
->vm_flags
& VM_ACCOUNT
)
918 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
920 while (start
!= end
) {
921 if (!tlb_start_valid
) {
926 if (unlikely(is_vm_hugetlb_page(vma
))) {
928 * It is undesirable to test vma->vm_file as it
929 * should be non-null for valid hugetlb area.
930 * However, vm_file will be NULL in the error
931 * cleanup path of do_mmap_pgoff. When
932 * hugetlbfs ->mmap method fails,
933 * do_mmap_pgoff() nullifies vma->vm_file
934 * before calling this function to clean up.
935 * Since no pte has actually been setup, it is
936 * safe to do nothing in this case.
939 unmap_hugepage_range(vma
, start
, end
, NULL
);
940 zap_work
-= (end
- start
) /
941 pages_per_huge_page(hstate_vma(vma
));
946 start
= unmap_page_range(*tlbp
, vma
,
947 start
, end
, &zap_work
, details
);
950 BUG_ON(start
!= end
);
954 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
956 if (need_resched() ||
957 (i_mmap_lock
&& spin_needbreak(i_mmap_lock
))) {
965 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
967 zap_work
= ZAP_BLOCK_SIZE
;
971 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
972 return start
; /* which is now the end (or restart) address */
976 * zap_page_range - remove user pages in a given range
977 * @vma: vm_area_struct holding the applicable pages
978 * @address: starting address of pages to zap
979 * @size: number of bytes to zap
980 * @details: details of nonlinear truncation or shared cache invalidation
982 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
983 unsigned long size
, struct zap_details
*details
)
985 struct mm_struct
*mm
= vma
->vm_mm
;
986 struct mmu_gather
*tlb
;
987 unsigned long end
= address
+ size
;
988 unsigned long nr_accounted
= 0;
991 tlb
= tlb_gather_mmu(mm
, 0);
992 update_hiwater_rss(mm
);
993 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
995 tlb_finish_mmu(tlb
, address
, end
);
1000 * zap_vma_ptes - remove ptes mapping the vma
1001 * @vma: vm_area_struct holding ptes to be zapped
1002 * @address: starting address of pages to zap
1003 * @size: number of bytes to zap
1005 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1007 * The entire address range must be fully contained within the vma.
1009 * Returns 0 if successful.
1011 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1014 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1015 !(vma
->vm_flags
& VM_PFNMAP
))
1017 zap_page_range(vma
, address
, size
, NULL
);
1020 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1023 * Do a quick page-table lookup for a single page.
1025 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
1034 struct mm_struct
*mm
= vma
->vm_mm
;
1036 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
1037 if (!IS_ERR(page
)) {
1038 BUG_ON(flags
& FOLL_GET
);
1043 pgd
= pgd_offset(mm
, address
);
1044 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
1047 pud
= pud_offset(pgd
, address
);
1050 if (pud_huge(*pud
)) {
1051 BUG_ON(flags
& FOLL_GET
);
1052 page
= follow_huge_pud(mm
, address
, pud
, flags
& FOLL_WRITE
);
1055 if (unlikely(pud_bad(*pud
)))
1058 pmd
= pmd_offset(pud
, address
);
1061 if (pmd_huge(*pmd
)) {
1062 BUG_ON(flags
& FOLL_GET
);
1063 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
1066 if (unlikely(pmd_bad(*pmd
)))
1069 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1072 if (!pte_present(pte
))
1074 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
1076 page
= vm_normal_page(vma
, address
, pte
);
1077 if (unlikely(!page
))
1080 if (flags
& FOLL_GET
)
1082 if (flags
& FOLL_TOUCH
) {
1083 if ((flags
& FOLL_WRITE
) &&
1084 !pte_dirty(pte
) && !PageDirty(page
))
1085 set_page_dirty(page
);
1086 mark_page_accessed(page
);
1089 pte_unmap_unlock(ptep
, ptl
);
1094 pte_unmap_unlock(ptep
, ptl
);
1095 return ERR_PTR(-EFAULT
);
1098 pte_unmap_unlock(ptep
, ptl
);
1101 /* Fall through to ZERO_PAGE handling */
1104 * When core dumping an enormous anonymous area that nobody
1105 * has touched so far, we don't want to allocate page tables.
1107 if (flags
& FOLL_ANON
) {
1108 page
= ZERO_PAGE(0);
1109 if (flags
& FOLL_GET
)
1111 BUG_ON(flags
& FOLL_WRITE
);
1116 /* Can we do the FOLL_ANON optimization? */
1117 static inline int use_zero_page(struct vm_area_struct
*vma
)
1120 * We don't want to optimize FOLL_ANON for make_pages_present()
1121 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1122 * we want to get the page from the page tables to make sure
1123 * that we serialize and update with any other user of that
1126 if (vma
->vm_flags
& (VM_LOCKED
| VM_SHARED
))
1129 * And if we have a fault routine, it's not an anonymous region.
1131 return !vma
->vm_ops
|| !vma
->vm_ops
->fault
;
1136 int __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1137 unsigned long start
, int len
, int flags
,
1138 struct page
**pages
, struct vm_area_struct
**vmas
)
1141 unsigned int vm_flags
= 0;
1142 int write
= !!(flags
& GUP_FLAGS_WRITE
);
1143 int force
= !!(flags
& GUP_FLAGS_FORCE
);
1144 int ignore
= !!(flags
& GUP_FLAGS_IGNORE_VMA_PERMISSIONS
);
1149 * Require read or write permissions.
1150 * If 'force' is set, we only require the "MAY" flags.
1152 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1153 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1157 struct vm_area_struct
*vma
;
1158 unsigned int foll_flags
;
1160 vma
= find_extend_vma(mm
, start
);
1161 if (!vma
&& in_gate_area(tsk
, start
)) {
1162 unsigned long pg
= start
& PAGE_MASK
;
1163 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1169 /* user gate pages are read-only */
1170 if (!ignore
&& write
)
1171 return i
? : -EFAULT
;
1173 pgd
= pgd_offset_k(pg
);
1175 pgd
= pgd_offset_gate(mm
, pg
);
1176 BUG_ON(pgd_none(*pgd
));
1177 pud
= pud_offset(pgd
, pg
);
1178 BUG_ON(pud_none(*pud
));
1179 pmd
= pmd_offset(pud
, pg
);
1181 return i
? : -EFAULT
;
1182 pte
= pte_offset_map(pmd
, pg
);
1183 if (pte_none(*pte
)) {
1185 return i
? : -EFAULT
;
1188 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1203 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1204 (!ignore
&& !(vm_flags
& vma
->vm_flags
)))
1205 return i
? : -EFAULT
;
1207 if (is_vm_hugetlb_page(vma
)) {
1208 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1209 &start
, &len
, i
, write
);
1213 foll_flags
= FOLL_TOUCH
;
1215 foll_flags
|= FOLL_GET
;
1216 if (!write
&& use_zero_page(vma
))
1217 foll_flags
|= FOLL_ANON
;
1223 * If tsk is ooming, cut off its access to large memory
1224 * allocations. It has a pending SIGKILL, but it can't
1225 * be processed until returning to user space.
1227 if (unlikely(test_tsk_thread_flag(tsk
, TIF_MEMDIE
)))
1228 return i
? i
: -ENOMEM
;
1231 foll_flags
|= FOLL_WRITE
;
1234 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1236 ret
= handle_mm_fault(mm
, vma
, start
,
1237 foll_flags
& FOLL_WRITE
);
1238 if (ret
& VM_FAULT_ERROR
) {
1239 if (ret
& VM_FAULT_OOM
)
1240 return i
? i
: -ENOMEM
;
1241 else if (ret
& VM_FAULT_SIGBUS
)
1242 return i
? i
: -EFAULT
;
1245 if (ret
& VM_FAULT_MAJOR
)
1251 * The VM_FAULT_WRITE bit tells us that
1252 * do_wp_page has broken COW when necessary,
1253 * even if maybe_mkwrite decided not to set
1254 * pte_write. We can thus safely do subsequent
1255 * page lookups as if they were reads.
1257 if (ret
& VM_FAULT_WRITE
)
1258 foll_flags
&= ~FOLL_WRITE
;
1263 return i
? i
: PTR_ERR(page
);
1267 flush_anon_page(vma
, page
, start
);
1268 flush_dcache_page(page
);
1275 } while (len
&& start
< vma
->vm_end
);
1280 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1281 unsigned long start
, int len
, int write
, int force
,
1282 struct page
**pages
, struct vm_area_struct
**vmas
)
1287 flags
|= GUP_FLAGS_WRITE
;
1289 flags
|= GUP_FLAGS_FORCE
;
1291 return __get_user_pages(tsk
, mm
,
1296 EXPORT_SYMBOL(get_user_pages
);
1298 pte_t
*get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1301 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1302 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1304 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1306 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1312 * This is the old fallback for page remapping.
1314 * For historical reasons, it only allows reserved pages. Only
1315 * old drivers should use this, and they needed to mark their
1316 * pages reserved for the old functions anyway.
1318 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1319 struct page
*page
, pgprot_t prot
)
1321 struct mm_struct
*mm
= vma
->vm_mm
;
1326 retval
= mem_cgroup_charge(page
, mm
, GFP_KERNEL
);
1334 flush_dcache_page(page
);
1335 pte
= get_locked_pte(mm
, addr
, &ptl
);
1339 if (!pte_none(*pte
))
1342 /* Ok, finally just insert the thing.. */
1344 inc_mm_counter(mm
, file_rss
);
1345 page_add_file_rmap(page
);
1346 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1349 pte_unmap_unlock(pte
, ptl
);
1352 pte_unmap_unlock(pte
, ptl
);
1354 mem_cgroup_uncharge_page(page
);
1360 * vm_insert_page - insert single page into user vma
1361 * @vma: user vma to map to
1362 * @addr: target user address of this page
1363 * @page: source kernel page
1365 * This allows drivers to insert individual pages they've allocated
1368 * The page has to be a nice clean _individual_ kernel allocation.
1369 * If you allocate a compound page, you need to have marked it as
1370 * such (__GFP_COMP), or manually just split the page up yourself
1371 * (see split_page()).
1373 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1374 * took an arbitrary page protection parameter. This doesn't allow
1375 * that. Your vma protection will have to be set up correctly, which
1376 * means that if you want a shared writable mapping, you'd better
1377 * ask for a shared writable mapping!
1379 * The page does not need to be reserved.
1381 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1384 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1386 if (!page_count(page
))
1388 vma
->vm_flags
|= VM_INSERTPAGE
;
1389 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1391 EXPORT_SYMBOL(vm_insert_page
);
1393 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1394 unsigned long pfn
, pgprot_t prot
)
1396 struct mm_struct
*mm
= vma
->vm_mm
;
1402 pte
= get_locked_pte(mm
, addr
, &ptl
);
1406 if (!pte_none(*pte
))
1409 /* Ok, finally just insert the thing.. */
1410 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
1411 set_pte_at(mm
, addr
, pte
, entry
);
1412 update_mmu_cache(vma
, addr
, entry
); /* XXX: why not for insert_page? */
1416 pte_unmap_unlock(pte
, ptl
);
1422 * vm_insert_pfn - insert single pfn into user vma
1423 * @vma: user vma to map to
1424 * @addr: target user address of this page
1425 * @pfn: source kernel pfn
1427 * Similar to vm_inert_page, this allows drivers to insert individual pages
1428 * they've allocated into a user vma. Same comments apply.
1430 * This function should only be called from a vm_ops->fault handler, and
1431 * in that case the handler should return NULL.
1433 * vma cannot be a COW mapping.
1435 * As this is called only for pages that do not currently exist, we
1436 * do not need to flush old virtual caches or the TLB.
1438 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1442 * Technically, architectures with pte_special can avoid all these
1443 * restrictions (same for remap_pfn_range). However we would like
1444 * consistency in testing and feature parity among all, so we should
1445 * try to keep these invariants in place for everybody.
1447 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1448 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1449 (VM_PFNMAP
|VM_MIXEDMAP
));
1450 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1451 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1453 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1455 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1457 EXPORT_SYMBOL(vm_insert_pfn
);
1459 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1462 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1464 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1468 * If we don't have pte special, then we have to use the pfn_valid()
1469 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1470 * refcount the page if pfn_valid is true (hence insert_page rather
1473 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
1476 page
= pfn_to_page(pfn
);
1477 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1479 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1481 EXPORT_SYMBOL(vm_insert_mixed
);
1484 * maps a range of physical memory into the requested pages. the old
1485 * mappings are removed. any references to nonexistent pages results
1486 * in null mappings (currently treated as "copy-on-access")
1488 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1489 unsigned long addr
, unsigned long end
,
1490 unsigned long pfn
, pgprot_t prot
)
1495 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1498 arch_enter_lazy_mmu_mode();
1500 BUG_ON(!pte_none(*pte
));
1501 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1503 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1504 arch_leave_lazy_mmu_mode();
1505 pte_unmap_unlock(pte
- 1, ptl
);
1509 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1510 unsigned long addr
, unsigned long end
,
1511 unsigned long pfn
, pgprot_t prot
)
1516 pfn
-= addr
>> PAGE_SHIFT
;
1517 pmd
= pmd_alloc(mm
, pud
, addr
);
1521 next
= pmd_addr_end(addr
, end
);
1522 if (remap_pte_range(mm
, pmd
, addr
, next
,
1523 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1525 } while (pmd
++, addr
= next
, addr
!= end
);
1529 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1530 unsigned long addr
, unsigned long end
,
1531 unsigned long pfn
, pgprot_t prot
)
1536 pfn
-= addr
>> PAGE_SHIFT
;
1537 pud
= pud_alloc(mm
, pgd
, addr
);
1541 next
= pud_addr_end(addr
, end
);
1542 if (remap_pmd_range(mm
, pud
, addr
, next
,
1543 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1545 } while (pud
++, addr
= next
, addr
!= end
);
1550 * remap_pfn_range - remap kernel memory to userspace
1551 * @vma: user vma to map to
1552 * @addr: target user address to start at
1553 * @pfn: physical address of kernel memory
1554 * @size: size of map area
1555 * @prot: page protection flags for this mapping
1557 * Note: this is only safe if the mm semaphore is held when called.
1559 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1560 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1564 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1565 struct mm_struct
*mm
= vma
->vm_mm
;
1569 * Physically remapped pages are special. Tell the
1570 * rest of the world about it:
1571 * VM_IO tells people not to look at these pages
1572 * (accesses can have side effects).
1573 * VM_RESERVED is specified all over the place, because
1574 * in 2.4 it kept swapout's vma scan off this vma; but
1575 * in 2.6 the LRU scan won't even find its pages, so this
1576 * flag means no more than count its pages in reserved_vm,
1577 * and omit it from core dump, even when VM_IO turned off.
1578 * VM_PFNMAP tells the core MM that the base pages are just
1579 * raw PFN mappings, and do not have a "struct page" associated
1582 * There's a horrible special case to handle copy-on-write
1583 * behaviour that some programs depend on. We mark the "original"
1584 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1586 if (is_cow_mapping(vma
->vm_flags
)) {
1587 if (addr
!= vma
->vm_start
|| end
!= vma
->vm_end
)
1589 vma
->vm_pgoff
= pfn
;
1592 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1594 BUG_ON(addr
>= end
);
1595 pfn
-= addr
>> PAGE_SHIFT
;
1596 pgd
= pgd_offset(mm
, addr
);
1597 flush_cache_range(vma
, addr
, end
);
1599 next
= pgd_addr_end(addr
, end
);
1600 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1601 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1604 } while (pgd
++, addr
= next
, addr
!= end
);
1607 EXPORT_SYMBOL(remap_pfn_range
);
1609 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1610 unsigned long addr
, unsigned long end
,
1611 pte_fn_t fn
, void *data
)
1616 spinlock_t
*uninitialized_var(ptl
);
1618 pte
= (mm
== &init_mm
) ?
1619 pte_alloc_kernel(pmd
, addr
) :
1620 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1624 BUG_ON(pmd_huge(*pmd
));
1626 token
= pmd_pgtable(*pmd
);
1629 err
= fn(pte
, token
, addr
, data
);
1632 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1635 pte_unmap_unlock(pte
-1, ptl
);
1639 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1640 unsigned long addr
, unsigned long end
,
1641 pte_fn_t fn
, void *data
)
1647 BUG_ON(pud_huge(*pud
));
1649 pmd
= pmd_alloc(mm
, pud
, addr
);
1653 next
= pmd_addr_end(addr
, end
);
1654 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1657 } while (pmd
++, addr
= next
, addr
!= end
);
1661 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1662 unsigned long addr
, unsigned long end
,
1663 pte_fn_t fn
, void *data
)
1669 pud
= pud_alloc(mm
, pgd
, addr
);
1673 next
= pud_addr_end(addr
, end
);
1674 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1677 } while (pud
++, addr
= next
, addr
!= end
);
1682 * Scan a region of virtual memory, filling in page tables as necessary
1683 * and calling a provided function on each leaf page table.
1685 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1686 unsigned long size
, pte_fn_t fn
, void *data
)
1690 unsigned long start
= addr
, end
= addr
+ size
;
1693 BUG_ON(addr
>= end
);
1694 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1695 pgd
= pgd_offset(mm
, addr
);
1697 next
= pgd_addr_end(addr
, end
);
1698 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1701 } while (pgd
++, addr
= next
, addr
!= end
);
1702 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1705 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1708 * handle_pte_fault chooses page fault handler according to an entry
1709 * which was read non-atomically. Before making any commitment, on
1710 * those architectures or configurations (e.g. i386 with PAE) which
1711 * might give a mix of unmatched parts, do_swap_page and do_file_page
1712 * must check under lock before unmapping the pte and proceeding
1713 * (but do_wp_page is only called after already making such a check;
1714 * and do_anonymous_page and do_no_page can safely check later on).
1716 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1717 pte_t
*page_table
, pte_t orig_pte
)
1720 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1721 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1722 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1724 same
= pte_same(*page_table
, orig_pte
);
1728 pte_unmap(page_table
);
1733 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1734 * servicing faults for write access. In the normal case, do always want
1735 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1736 * that do not have writing enabled, when used by access_process_vm.
1738 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1740 if (likely(vma
->vm_flags
& VM_WRITE
))
1741 pte
= pte_mkwrite(pte
);
1745 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1748 * If the source page was a PFN mapping, we don't have
1749 * a "struct page" for it. We do a best-effort copy by
1750 * just copying from the original user address. If that
1751 * fails, we just zero-fill it. Live with it.
1753 if (unlikely(!src
)) {
1754 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1755 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1758 * This really shouldn't fail, because the page is there
1759 * in the page tables. But it might just be unreadable,
1760 * in which case we just give up and fill the result with
1763 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1764 memset(kaddr
, 0, PAGE_SIZE
);
1765 kunmap_atomic(kaddr
, KM_USER0
);
1766 flush_dcache_page(dst
);
1768 copy_user_highpage(dst
, src
, va
, vma
);
1772 * This routine handles present pages, when users try to write
1773 * to a shared page. It is done by copying the page to a new address
1774 * and decrementing the shared-page counter for the old page.
1776 * Note that this routine assumes that the protection checks have been
1777 * done by the caller (the low-level page fault routine in most cases).
1778 * Thus we can safely just mark it writable once we've done any necessary
1781 * We also mark the page dirty at this point even though the page will
1782 * change only once the write actually happens. This avoids a few races,
1783 * and potentially makes it more efficient.
1785 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1786 * but allow concurrent faults), with pte both mapped and locked.
1787 * We return with mmap_sem still held, but pte unmapped and unlocked.
1789 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1790 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1791 spinlock_t
*ptl
, pte_t orig_pte
)
1793 struct page
*old_page
, *new_page
;
1795 int reuse
= 0, ret
= 0;
1796 int page_mkwrite
= 0;
1797 struct page
*dirty_page
= NULL
;
1799 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1802 * VM_MIXEDMAP !pfn_valid() case
1804 * We should not cow pages in a shared writeable mapping.
1805 * Just mark the pages writable as we can't do any dirty
1806 * accounting on raw pfn maps.
1808 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1809 (VM_WRITE
|VM_SHARED
))
1815 * Take out anonymous pages first, anonymous shared vmas are
1816 * not dirty accountable.
1818 if (PageAnon(old_page
)) {
1819 if (trylock_page(old_page
)) {
1820 reuse
= can_share_swap_page(old_page
);
1821 unlock_page(old_page
);
1823 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1824 (VM_WRITE
|VM_SHARED
))) {
1826 * Only catch write-faults on shared writable pages,
1827 * read-only shared pages can get COWed by
1828 * get_user_pages(.write=1, .force=1).
1830 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
1832 * Notify the address space that the page is about to
1833 * become writable so that it can prohibit this or wait
1834 * for the page to get into an appropriate state.
1836 * We do this without the lock held, so that it can
1837 * sleep if it needs to.
1839 page_cache_get(old_page
);
1840 pte_unmap_unlock(page_table
, ptl
);
1842 if (vma
->vm_ops
->page_mkwrite(vma
, old_page
) < 0)
1843 goto unwritable_page
;
1846 * Since we dropped the lock we need to revalidate
1847 * the PTE as someone else may have changed it. If
1848 * they did, we just return, as we can count on the
1849 * MMU to tell us if they didn't also make it writable.
1851 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1853 page_cache_release(old_page
);
1854 if (!pte_same(*page_table
, orig_pte
))
1859 dirty_page
= old_page
;
1860 get_page(dirty_page
);
1866 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1867 entry
= pte_mkyoung(orig_pte
);
1868 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1869 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
1870 update_mmu_cache(vma
, address
, entry
);
1871 ret
|= VM_FAULT_WRITE
;
1876 * Ok, we need to copy. Oh, well..
1878 page_cache_get(old_page
);
1880 pte_unmap_unlock(page_table
, ptl
);
1882 if (unlikely(anon_vma_prepare(vma
)))
1884 VM_BUG_ON(old_page
== ZERO_PAGE(0));
1885 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
1889 * Don't let another task, with possibly unlocked vma,
1890 * keep the mlocked page.
1892 if (vma
->vm_flags
& VM_LOCKED
) {
1893 lock_page(old_page
); /* for LRU manipulation */
1894 clear_page_mlock(old_page
);
1895 unlock_page(old_page
);
1897 cow_user_page(new_page
, old_page
, address
, vma
);
1898 __SetPageUptodate(new_page
);
1900 if (mem_cgroup_charge(new_page
, mm
, GFP_KERNEL
))
1904 * Re-check the pte - we dropped the lock
1906 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1907 if (likely(pte_same(*page_table
, orig_pte
))) {
1909 if (!PageAnon(old_page
)) {
1910 dec_mm_counter(mm
, file_rss
);
1911 inc_mm_counter(mm
, anon_rss
);
1914 inc_mm_counter(mm
, anon_rss
);
1915 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1916 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1917 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1919 * Clear the pte entry and flush it first, before updating the
1920 * pte with the new entry. This will avoid a race condition
1921 * seen in the presence of one thread doing SMC and another
1924 ptep_clear_flush_notify(vma
, address
, page_table
);
1925 SetPageSwapBacked(new_page
);
1926 lru_cache_add_active_or_unevictable(new_page
, vma
);
1927 page_add_new_anon_rmap(new_page
, vma
, address
);
1929 //TODO: is this safe? do_anonymous_page() does it this way.
1930 set_pte_at(mm
, address
, page_table
, entry
);
1931 update_mmu_cache(vma
, address
, entry
);
1934 * Only after switching the pte to the new page may
1935 * we remove the mapcount here. Otherwise another
1936 * process may come and find the rmap count decremented
1937 * before the pte is switched to the new page, and
1938 * "reuse" the old page writing into it while our pte
1939 * here still points into it and can be read by other
1942 * The critical issue is to order this
1943 * page_remove_rmap with the ptp_clear_flush above.
1944 * Those stores are ordered by (if nothing else,)
1945 * the barrier present in the atomic_add_negative
1946 * in page_remove_rmap.
1948 * Then the TLB flush in ptep_clear_flush ensures that
1949 * no process can access the old page before the
1950 * decremented mapcount is visible. And the old page
1951 * cannot be reused until after the decremented
1952 * mapcount is visible. So transitively, TLBs to
1953 * old page will be flushed before it can be reused.
1955 page_remove_rmap(old_page
, vma
);
1958 /* Free the old page.. */
1959 new_page
= old_page
;
1960 ret
|= VM_FAULT_WRITE
;
1962 mem_cgroup_uncharge_page(new_page
);
1965 page_cache_release(new_page
);
1967 page_cache_release(old_page
);
1969 pte_unmap_unlock(page_table
, ptl
);
1972 file_update_time(vma
->vm_file
);
1975 * Yes, Virginia, this is actually required to prevent a race
1976 * with clear_page_dirty_for_io() from clearing the page dirty
1977 * bit after it clear all dirty ptes, but before a racing
1978 * do_wp_page installs a dirty pte.
1980 * do_no_page is protected similarly.
1982 wait_on_page_locked(dirty_page
);
1983 set_page_dirty_balance(dirty_page
, page_mkwrite
);
1984 put_page(dirty_page
);
1988 page_cache_release(new_page
);
1991 page_cache_release(old_page
);
1992 return VM_FAULT_OOM
;
1995 page_cache_release(old_page
);
1996 return VM_FAULT_SIGBUS
;
2000 * Helper functions for unmap_mapping_range().
2002 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2004 * We have to restart searching the prio_tree whenever we drop the lock,
2005 * since the iterator is only valid while the lock is held, and anyway
2006 * a later vma might be split and reinserted earlier while lock dropped.
2008 * The list of nonlinear vmas could be handled more efficiently, using
2009 * a placeholder, but handle it in the same way until a need is shown.
2010 * It is important to search the prio_tree before nonlinear list: a vma
2011 * may become nonlinear and be shifted from prio_tree to nonlinear list
2012 * while the lock is dropped; but never shifted from list to prio_tree.
2014 * In order to make forward progress despite restarting the search,
2015 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2016 * quickly skip it next time around. Since the prio_tree search only
2017 * shows us those vmas affected by unmapping the range in question, we
2018 * can't efficiently keep all vmas in step with mapping->truncate_count:
2019 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2020 * mapping->truncate_count and vma->vm_truncate_count are protected by
2023 * In order to make forward progress despite repeatedly restarting some
2024 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2025 * and restart from that address when we reach that vma again. It might
2026 * have been split or merged, shrunk or extended, but never shifted: so
2027 * restart_addr remains valid so long as it remains in the vma's range.
2028 * unmap_mapping_range forces truncate_count to leap over page-aligned
2029 * values so we can save vma's restart_addr in its truncate_count field.
2031 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2033 static void reset_vma_truncate_counts(struct address_space
*mapping
)
2035 struct vm_area_struct
*vma
;
2036 struct prio_tree_iter iter
;
2038 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
2039 vma
->vm_truncate_count
= 0;
2040 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
2041 vma
->vm_truncate_count
= 0;
2044 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2045 unsigned long start_addr
, unsigned long end_addr
,
2046 struct zap_details
*details
)
2048 unsigned long restart_addr
;
2052 * files that support invalidating or truncating portions of the
2053 * file from under mmaped areas must have their ->fault function
2054 * return a locked page (and set VM_FAULT_LOCKED in the return).
2055 * This provides synchronisation against concurrent unmapping here.
2059 restart_addr
= vma
->vm_truncate_count
;
2060 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
2061 start_addr
= restart_addr
;
2062 if (start_addr
>= end_addr
) {
2063 /* Top of vma has been split off since last time */
2064 vma
->vm_truncate_count
= details
->truncate_count
;
2069 restart_addr
= zap_page_range(vma
, start_addr
,
2070 end_addr
- start_addr
, details
);
2071 need_break
= need_resched() || spin_needbreak(details
->i_mmap_lock
);
2073 if (restart_addr
>= end_addr
) {
2074 /* We have now completed this vma: mark it so */
2075 vma
->vm_truncate_count
= details
->truncate_count
;
2079 /* Note restart_addr in vma's truncate_count field */
2080 vma
->vm_truncate_count
= restart_addr
;
2085 spin_unlock(details
->i_mmap_lock
);
2087 spin_lock(details
->i_mmap_lock
);
2091 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
2092 struct zap_details
*details
)
2094 struct vm_area_struct
*vma
;
2095 struct prio_tree_iter iter
;
2096 pgoff_t vba
, vea
, zba
, zea
;
2099 vma_prio_tree_foreach(vma
, &iter
, root
,
2100 details
->first_index
, details
->last_index
) {
2101 /* Skip quickly over those we have already dealt with */
2102 if (vma
->vm_truncate_count
== details
->truncate_count
)
2105 vba
= vma
->vm_pgoff
;
2106 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
2107 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2108 zba
= details
->first_index
;
2111 zea
= details
->last_index
;
2115 if (unmap_mapping_range_vma(vma
,
2116 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2117 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2123 static inline void unmap_mapping_range_list(struct list_head
*head
,
2124 struct zap_details
*details
)
2126 struct vm_area_struct
*vma
;
2129 * In nonlinear VMAs there is no correspondence between virtual address
2130 * offset and file offset. So we must perform an exhaustive search
2131 * across *all* the pages in each nonlinear VMA, not just the pages
2132 * whose virtual address lies outside the file truncation point.
2135 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
2136 /* Skip quickly over those we have already dealt with */
2137 if (vma
->vm_truncate_count
== details
->truncate_count
)
2139 details
->nonlinear_vma
= vma
;
2140 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
2141 vma
->vm_end
, details
) < 0)
2147 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2148 * @mapping: the address space containing mmaps to be unmapped.
2149 * @holebegin: byte in first page to unmap, relative to the start of
2150 * the underlying file. This will be rounded down to a PAGE_SIZE
2151 * boundary. Note that this is different from vmtruncate(), which
2152 * must keep the partial page. In contrast, we must get rid of
2154 * @holelen: size of prospective hole in bytes. This will be rounded
2155 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2157 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2158 * but 0 when invalidating pagecache, don't throw away private data.
2160 void unmap_mapping_range(struct address_space
*mapping
,
2161 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2163 struct zap_details details
;
2164 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2165 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2167 /* Check for overflow. */
2168 if (sizeof(holelen
) > sizeof(hlen
)) {
2170 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2171 if (holeend
& ~(long long)ULONG_MAX
)
2172 hlen
= ULONG_MAX
- hba
+ 1;
2175 details
.check_mapping
= even_cows
? NULL
: mapping
;
2176 details
.nonlinear_vma
= NULL
;
2177 details
.first_index
= hba
;
2178 details
.last_index
= hba
+ hlen
- 1;
2179 if (details
.last_index
< details
.first_index
)
2180 details
.last_index
= ULONG_MAX
;
2181 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
2183 spin_lock(&mapping
->i_mmap_lock
);
2185 /* Protect against endless unmapping loops */
2186 mapping
->truncate_count
++;
2187 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
2188 if (mapping
->truncate_count
== 0)
2189 reset_vma_truncate_counts(mapping
);
2190 mapping
->truncate_count
++;
2192 details
.truncate_count
= mapping
->truncate_count
;
2194 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
2195 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2196 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2197 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2198 spin_unlock(&mapping
->i_mmap_lock
);
2200 EXPORT_SYMBOL(unmap_mapping_range
);
2203 * vmtruncate - unmap mappings "freed" by truncate() syscall
2204 * @inode: inode of the file used
2205 * @offset: file offset to start truncating
2207 * NOTE! We have to be ready to update the memory sharing
2208 * between the file and the memory map for a potential last
2209 * incomplete page. Ugly, but necessary.
2211 int vmtruncate(struct inode
* inode
, loff_t offset
)
2213 if (inode
->i_size
< offset
) {
2214 unsigned long limit
;
2216 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2217 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2219 if (offset
> inode
->i_sb
->s_maxbytes
)
2221 i_size_write(inode
, offset
);
2223 struct address_space
*mapping
= inode
->i_mapping
;
2226 * truncation of in-use swapfiles is disallowed - it would
2227 * cause subsequent swapout to scribble on the now-freed
2230 if (IS_SWAPFILE(inode
))
2232 i_size_write(inode
, offset
);
2235 * unmap_mapping_range is called twice, first simply for
2236 * efficiency so that truncate_inode_pages does fewer
2237 * single-page unmaps. However after this first call, and
2238 * before truncate_inode_pages finishes, it is possible for
2239 * private pages to be COWed, which remain after
2240 * truncate_inode_pages finishes, hence the second
2241 * unmap_mapping_range call must be made for correctness.
2243 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2244 truncate_inode_pages(mapping
, offset
);
2245 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2248 if (inode
->i_op
&& inode
->i_op
->truncate
)
2249 inode
->i_op
->truncate(inode
);
2253 send_sig(SIGXFSZ
, current
, 0);
2257 EXPORT_SYMBOL(vmtruncate
);
2259 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2261 struct address_space
*mapping
= inode
->i_mapping
;
2264 * If the underlying filesystem is not going to provide
2265 * a way to truncate a range of blocks (punch a hole) -
2266 * we should return failure right now.
2268 if (!inode
->i_op
|| !inode
->i_op
->truncate_range
)
2271 mutex_lock(&inode
->i_mutex
);
2272 down_write(&inode
->i_alloc_sem
);
2273 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2274 truncate_inode_pages_range(mapping
, offset
, end
);
2275 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2276 inode
->i_op
->truncate_range(inode
, offset
, end
);
2277 up_write(&inode
->i_alloc_sem
);
2278 mutex_unlock(&inode
->i_mutex
);
2284 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2285 * but allow concurrent faults), and pte mapped but not yet locked.
2286 * We return with mmap_sem still held, but pte unmapped and unlocked.
2288 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2289 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2290 int write_access
, pte_t orig_pte
)
2298 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2301 entry
= pte_to_swp_entry(orig_pte
);
2302 if (is_migration_entry(entry
)) {
2303 migration_entry_wait(mm
, pmd
, address
);
2306 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2307 page
= lookup_swap_cache(entry
);
2309 grab_swap_token(); /* Contend for token _before_ read-in */
2310 page
= swapin_readahead(entry
,
2311 GFP_HIGHUSER_MOVABLE
, vma
, address
);
2314 * Back out if somebody else faulted in this pte
2315 * while we released the pte lock.
2317 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2318 if (likely(pte_same(*page_table
, orig_pte
)))
2320 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2324 /* Had to read the page from swap area: Major fault */
2325 ret
= VM_FAULT_MAJOR
;
2326 count_vm_event(PGMAJFAULT
);
2329 if (mem_cgroup_charge(page
, mm
, GFP_KERNEL
)) {
2330 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2335 mark_page_accessed(page
);
2337 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2340 * Back out if somebody else already faulted in this pte.
2342 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2343 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2346 if (unlikely(!PageUptodate(page
))) {
2347 ret
= VM_FAULT_SIGBUS
;
2351 /* The page isn't present yet, go ahead with the fault. */
2353 inc_mm_counter(mm
, anon_rss
);
2354 pte
= mk_pte(page
, vma
->vm_page_prot
);
2355 if (write_access
&& can_share_swap_page(page
)) {
2356 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2360 flush_icache_page(vma
, page
);
2361 set_pte_at(mm
, address
, page_table
, pte
);
2362 page_add_anon_rmap(page
, vma
, address
);
2365 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
2366 remove_exclusive_swap_page(page
);
2370 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
2371 if (ret
& VM_FAULT_ERROR
)
2372 ret
&= VM_FAULT_ERROR
;
2376 /* No need to invalidate - it was non-present before */
2377 update_mmu_cache(vma
, address
, pte
);
2379 pte_unmap_unlock(page_table
, ptl
);
2383 mem_cgroup_uncharge_page(page
);
2384 pte_unmap_unlock(page_table
, ptl
);
2386 page_cache_release(page
);
2391 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2392 * but allow concurrent faults), and pte mapped but not yet locked.
2393 * We return with mmap_sem still held, but pte unmapped and unlocked.
2395 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2396 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2403 /* Allocate our own private page. */
2404 pte_unmap(page_table
);
2406 if (unlikely(anon_vma_prepare(vma
)))
2408 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2411 __SetPageUptodate(page
);
2413 if (mem_cgroup_charge(page
, mm
, GFP_KERNEL
))
2416 entry
= mk_pte(page
, vma
->vm_page_prot
);
2417 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2419 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2420 if (!pte_none(*page_table
))
2422 inc_mm_counter(mm
, anon_rss
);
2423 SetPageSwapBacked(page
);
2424 lru_cache_add_active_or_unevictable(page
, vma
);
2425 page_add_new_anon_rmap(page
, vma
, address
);
2426 set_pte_at(mm
, address
, page_table
, entry
);
2428 /* No need to invalidate - it was non-present before */
2429 update_mmu_cache(vma
, address
, entry
);
2431 pte_unmap_unlock(page_table
, ptl
);
2434 mem_cgroup_uncharge_page(page
);
2435 page_cache_release(page
);
2438 page_cache_release(page
);
2440 return VM_FAULT_OOM
;
2444 * __do_fault() tries to create a new page mapping. It aggressively
2445 * tries to share with existing pages, but makes a separate copy if
2446 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2447 * the next page fault.
2449 * As this is called only for pages that do not currently exist, we
2450 * do not need to flush old virtual caches or the TLB.
2452 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2453 * but allow concurrent faults), and pte neither mapped nor locked.
2454 * We return with mmap_sem still held, but pte unmapped and unlocked.
2456 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2457 unsigned long address
, pmd_t
*pmd
,
2458 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2465 struct page
*dirty_page
= NULL
;
2466 struct vm_fault vmf
;
2468 int page_mkwrite
= 0;
2470 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2475 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2476 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2480 * For consistency in subsequent calls, make the faulted page always
2483 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2484 lock_page(vmf
.page
);
2486 VM_BUG_ON(!PageLocked(vmf
.page
));
2489 * Should we do an early C-O-W break?
2492 if (flags
& FAULT_FLAG_WRITE
) {
2493 if (!(vma
->vm_flags
& VM_SHARED
)) {
2495 if (unlikely(anon_vma_prepare(vma
))) {
2499 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2506 * Don't let another task, with possibly unlocked vma,
2507 * keep the mlocked page.
2509 if (vma
->vm_flags
& VM_LOCKED
)
2510 clear_page_mlock(vmf
.page
);
2511 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2512 __SetPageUptodate(page
);
2515 * If the page will be shareable, see if the backing
2516 * address space wants to know that the page is about
2517 * to become writable
2519 if (vma
->vm_ops
->page_mkwrite
) {
2521 if (vma
->vm_ops
->page_mkwrite(vma
, page
) < 0) {
2522 ret
= VM_FAULT_SIGBUS
;
2523 anon
= 1; /* no anon but release vmf.page */
2528 * XXX: this is not quite right (racy vs
2529 * invalidate) to unlock and relock the page
2530 * like this, however a better fix requires
2531 * reworking page_mkwrite locking API, which
2532 * is better done later.
2534 if (!page
->mapping
) {
2536 anon
= 1; /* no anon but release vmf.page */
2545 if (mem_cgroup_charge(page
, mm
, GFP_KERNEL
)) {
2550 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2553 * This silly early PAGE_DIRTY setting removes a race
2554 * due to the bad i386 page protection. But it's valid
2555 * for other architectures too.
2557 * Note that if write_access is true, we either now have
2558 * an exclusive copy of the page, or this is a shared mapping,
2559 * so we can make it writable and dirty to avoid having to
2560 * handle that later.
2562 /* Only go through if we didn't race with anybody else... */
2563 if (likely(pte_same(*page_table
, orig_pte
))) {
2564 flush_icache_page(vma
, page
);
2565 entry
= mk_pte(page
, vma
->vm_page_prot
);
2566 if (flags
& FAULT_FLAG_WRITE
)
2567 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2569 inc_mm_counter(mm
, anon_rss
);
2570 SetPageSwapBacked(page
);
2571 lru_cache_add_active_or_unevictable(page
, vma
);
2572 page_add_new_anon_rmap(page
, vma
, address
);
2574 inc_mm_counter(mm
, file_rss
);
2575 page_add_file_rmap(page
);
2576 if (flags
& FAULT_FLAG_WRITE
) {
2578 get_page(dirty_page
);
2581 //TODO: is this safe? do_anonymous_page() does it this way.
2582 set_pte_at(mm
, address
, page_table
, entry
);
2584 /* no need to invalidate: a not-present page won't be cached */
2585 update_mmu_cache(vma
, address
, entry
);
2587 mem_cgroup_uncharge_page(page
);
2589 page_cache_release(page
);
2591 anon
= 1; /* no anon but release faulted_page */
2594 pte_unmap_unlock(page_table
, ptl
);
2597 unlock_page(vmf
.page
);
2600 page_cache_release(vmf
.page
);
2601 else if (dirty_page
) {
2603 file_update_time(vma
->vm_file
);
2605 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2606 put_page(dirty_page
);
2612 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2613 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2614 int write_access
, pte_t orig_pte
)
2616 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2617 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2618 unsigned int flags
= (write_access
? FAULT_FLAG_WRITE
: 0);
2620 pte_unmap(page_table
);
2621 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2625 * Fault of a previously existing named mapping. Repopulate the pte
2626 * from the encoded file_pte if possible. This enables swappable
2629 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2630 * but allow concurrent faults), and pte mapped but not yet locked.
2631 * We return with mmap_sem still held, but pte unmapped and unlocked.
2633 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2634 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2635 int write_access
, pte_t orig_pte
)
2637 unsigned int flags
= FAULT_FLAG_NONLINEAR
|
2638 (write_access
? FAULT_FLAG_WRITE
: 0);
2641 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2644 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
) ||
2645 !(vma
->vm_flags
& VM_CAN_NONLINEAR
))) {
2647 * Page table corrupted: show pte and kill process.
2649 print_bad_pte(vma
, orig_pte
, address
);
2650 return VM_FAULT_OOM
;
2653 pgoff
= pte_to_pgoff(orig_pte
);
2654 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2658 * These routines also need to handle stuff like marking pages dirty
2659 * and/or accessed for architectures that don't do it in hardware (most
2660 * RISC architectures). The early dirtying is also good on the i386.
2662 * There is also a hook called "update_mmu_cache()" that architectures
2663 * with external mmu caches can use to update those (ie the Sparc or
2664 * PowerPC hashed page tables that act as extended TLBs).
2666 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2667 * but allow concurrent faults), and pte mapped but not yet locked.
2668 * We return with mmap_sem still held, but pte unmapped and unlocked.
2670 static inline int handle_pte_fault(struct mm_struct
*mm
,
2671 struct vm_area_struct
*vma
, unsigned long address
,
2672 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
2678 if (!pte_present(entry
)) {
2679 if (pte_none(entry
)) {
2681 if (likely(vma
->vm_ops
->fault
))
2682 return do_linear_fault(mm
, vma
, address
,
2683 pte
, pmd
, write_access
, entry
);
2685 return do_anonymous_page(mm
, vma
, address
,
2686 pte
, pmd
, write_access
);
2688 if (pte_file(entry
))
2689 return do_nonlinear_fault(mm
, vma
, address
,
2690 pte
, pmd
, write_access
, entry
);
2691 return do_swap_page(mm
, vma
, address
,
2692 pte
, pmd
, write_access
, entry
);
2695 ptl
= pte_lockptr(mm
, pmd
);
2697 if (unlikely(!pte_same(*pte
, entry
)))
2700 if (!pte_write(entry
))
2701 return do_wp_page(mm
, vma
, address
,
2702 pte
, pmd
, ptl
, entry
);
2703 entry
= pte_mkdirty(entry
);
2705 entry
= pte_mkyoung(entry
);
2706 if (ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
)) {
2707 update_mmu_cache(vma
, address
, entry
);
2710 * This is needed only for protection faults but the arch code
2711 * is not yet telling us if this is a protection fault or not.
2712 * This still avoids useless tlb flushes for .text page faults
2716 flush_tlb_page(vma
, address
);
2719 pte_unmap_unlock(pte
, ptl
);
2724 * By the time we get here, we already hold the mm semaphore
2726 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2727 unsigned long address
, int write_access
)
2734 __set_current_state(TASK_RUNNING
);
2736 count_vm_event(PGFAULT
);
2738 if (unlikely(is_vm_hugetlb_page(vma
)))
2739 return hugetlb_fault(mm
, vma
, address
, write_access
);
2741 pgd
= pgd_offset(mm
, address
);
2742 pud
= pud_alloc(mm
, pgd
, address
);
2744 return VM_FAULT_OOM
;
2745 pmd
= pmd_alloc(mm
, pud
, address
);
2747 return VM_FAULT_OOM
;
2748 pte
= pte_alloc_map(mm
, pmd
, address
);
2750 return VM_FAULT_OOM
;
2752 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2755 #ifndef __PAGETABLE_PUD_FOLDED
2757 * Allocate page upper directory.
2758 * We've already handled the fast-path in-line.
2760 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2762 pud_t
*new = pud_alloc_one(mm
, address
);
2766 smp_wmb(); /* See comment in __pte_alloc */
2768 spin_lock(&mm
->page_table_lock
);
2769 if (pgd_present(*pgd
)) /* Another has populated it */
2772 pgd_populate(mm
, pgd
, new);
2773 spin_unlock(&mm
->page_table_lock
);
2776 #endif /* __PAGETABLE_PUD_FOLDED */
2778 #ifndef __PAGETABLE_PMD_FOLDED
2780 * Allocate page middle directory.
2781 * We've already handled the fast-path in-line.
2783 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2785 pmd_t
*new = pmd_alloc_one(mm
, address
);
2789 smp_wmb(); /* See comment in __pte_alloc */
2791 spin_lock(&mm
->page_table_lock
);
2792 #ifndef __ARCH_HAS_4LEVEL_HACK
2793 if (pud_present(*pud
)) /* Another has populated it */
2796 pud_populate(mm
, pud
, new);
2798 if (pgd_present(*pud
)) /* Another has populated it */
2801 pgd_populate(mm
, pud
, new);
2802 #endif /* __ARCH_HAS_4LEVEL_HACK */
2803 spin_unlock(&mm
->page_table_lock
);
2806 #endif /* __PAGETABLE_PMD_FOLDED */
2808 int make_pages_present(unsigned long addr
, unsigned long end
)
2810 int ret
, len
, write
;
2811 struct vm_area_struct
* vma
;
2813 vma
= find_vma(current
->mm
, addr
);
2816 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2817 BUG_ON(addr
>= end
);
2818 BUG_ON(end
> vma
->vm_end
);
2819 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
2820 ret
= get_user_pages(current
, current
->mm
, addr
,
2821 len
, write
, 0, NULL
, NULL
);
2824 SUS require strange return value to mlock
2825 - invalid addr generate to ENOMEM.
2826 - out of memory should generate EAGAIN.
2830 else if (ret
== -ENOMEM
)
2834 return ret
== len
? 0 : -ENOMEM
;
2837 #if !defined(__HAVE_ARCH_GATE_AREA)
2839 #if defined(AT_SYSINFO_EHDR)
2840 static struct vm_area_struct gate_vma
;
2842 static int __init
gate_vma_init(void)
2844 gate_vma
.vm_mm
= NULL
;
2845 gate_vma
.vm_start
= FIXADDR_USER_START
;
2846 gate_vma
.vm_end
= FIXADDR_USER_END
;
2847 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
2848 gate_vma
.vm_page_prot
= __P101
;
2850 * Make sure the vDSO gets into every core dump.
2851 * Dumping its contents makes post-mortem fully interpretable later
2852 * without matching up the same kernel and hardware config to see
2853 * what PC values meant.
2855 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
2858 __initcall(gate_vma_init
);
2861 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2863 #ifdef AT_SYSINFO_EHDR
2870 int in_gate_area_no_task(unsigned long addr
)
2872 #ifdef AT_SYSINFO_EHDR
2873 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2879 #endif /* __HAVE_ARCH_GATE_AREA */
2881 #ifdef CONFIG_HAVE_IOREMAP_PROT
2882 static resource_size_t
follow_phys(struct vm_area_struct
*vma
,
2883 unsigned long address
, unsigned int flags
,
2884 unsigned long *prot
)
2891 resource_size_t phys_addr
= 0;
2892 struct mm_struct
*mm
= vma
->vm_mm
;
2894 VM_BUG_ON(!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)));
2896 pgd
= pgd_offset(mm
, address
);
2897 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
2900 pud
= pud_offset(pgd
, address
);
2901 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
2904 pmd
= pmd_offset(pud
, address
);
2905 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
2908 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
2912 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2917 if (!pte_present(pte
))
2919 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
2921 phys_addr
= pte_pfn(pte
);
2922 phys_addr
<<= PAGE_SHIFT
; /* Shift here to avoid overflow on PAE */
2924 *prot
= pgprot_val(pte_pgprot(pte
));
2927 pte_unmap_unlock(ptep
, ptl
);
2934 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
2935 void *buf
, int len
, int write
)
2937 resource_size_t phys_addr
;
2938 unsigned long prot
= 0;
2940 int offset
= addr
& (PAGE_SIZE
-1);
2942 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
2945 phys_addr
= follow_phys(vma
, addr
, write
, &prot
);
2950 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
2952 memcpy_toio(maddr
+ offset
, buf
, len
);
2954 memcpy_fromio(buf
, maddr
+ offset
, len
);
2962 * Access another process' address space.
2963 * Source/target buffer must be kernel space,
2964 * Do not walk the page table directly, use get_user_pages
2966 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
2968 struct mm_struct
*mm
;
2969 struct vm_area_struct
*vma
;
2970 void *old_buf
= buf
;
2972 mm
= get_task_mm(tsk
);
2976 down_read(&mm
->mmap_sem
);
2977 /* ignore errors, just check how much was successfully transferred */
2979 int bytes
, ret
, offset
;
2981 struct page
*page
= NULL
;
2983 ret
= get_user_pages(tsk
, mm
, addr
, 1,
2984 write
, 1, &page
, &vma
);
2987 * Check if this is a VM_IO | VM_PFNMAP VMA, which
2988 * we can access using slightly different code.
2990 #ifdef CONFIG_HAVE_IOREMAP_PROT
2991 vma
= find_vma(mm
, addr
);
2994 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
2995 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
3003 offset
= addr
& (PAGE_SIZE
-1);
3004 if (bytes
> PAGE_SIZE
-offset
)
3005 bytes
= PAGE_SIZE
-offset
;
3009 copy_to_user_page(vma
, page
, addr
,
3010 maddr
+ offset
, buf
, bytes
);
3011 set_page_dirty_lock(page
);
3013 copy_from_user_page(vma
, page
, addr
,
3014 buf
, maddr
+ offset
, bytes
);
3017 page_cache_release(page
);
3023 up_read(&mm
->mmap_sem
);
3026 return buf
- old_buf
;
3030 * Print the name of a VMA.
3032 void print_vma_addr(char *prefix
, unsigned long ip
)
3034 struct mm_struct
*mm
= current
->mm
;
3035 struct vm_area_struct
*vma
;
3038 * Do not print if we are in atomic
3039 * contexts (in exception stacks, etc.):
3041 if (preempt_count())
3044 down_read(&mm
->mmap_sem
);
3045 vma
= find_vma(mm
, ip
);
3046 if (vma
&& vma
->vm_file
) {
3047 struct file
*f
= vma
->vm_file
;
3048 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
3052 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
3055 s
= strrchr(p
, '/');
3058 printk("%s%s[%lx+%lx]", prefix
, p
,
3060 vma
->vm_end
- vma
->vm_start
);
3061 free_page((unsigned long)buf
);
3064 up_read(¤t
->mm
->mmap_sem
);