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>
55 #include <linux/kallsyms.h>
56 #include <linux/swapops.h>
57 #include <linux/elf.h>
60 #include <asm/pgalloc.h>
61 #include <asm/uaccess.h>
63 #include <asm/tlbflush.h>
64 #include <asm/pgtable.h>
68 #ifndef CONFIG_NEED_MULTIPLE_NODES
69 /* use the per-pgdat data instead for discontigmem - mbligh */
70 unsigned long max_mapnr
;
73 EXPORT_SYMBOL(max_mapnr
);
74 EXPORT_SYMBOL(mem_map
);
77 unsigned long num_physpages
;
79 * A number of key systems in x86 including ioremap() rely on the assumption
80 * that high_memory defines the upper bound on direct map memory, then end
81 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
82 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
87 EXPORT_SYMBOL(num_physpages
);
88 EXPORT_SYMBOL(high_memory
);
91 * Randomize the address space (stacks, mmaps, brk, etc.).
93 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
94 * as ancient (libc5 based) binaries can segfault. )
96 int randomize_va_space __read_mostly
=
97 #ifdef CONFIG_COMPAT_BRK
103 static int __init
disable_randmaps(char *s
)
105 randomize_va_space
= 0;
108 __setup("norandmaps", disable_randmaps
);
112 * If a p?d_bad entry is found while walking page tables, report
113 * the error, before resetting entry to p?d_none. Usually (but
114 * very seldom) called out from the p?d_none_or_clear_bad macros.
117 void pgd_clear_bad(pgd_t
*pgd
)
123 void pud_clear_bad(pud_t
*pud
)
129 void pmd_clear_bad(pmd_t
*pmd
)
136 * Note: this doesn't free the actual pages themselves. That
137 * has been handled earlier when unmapping all the memory regions.
139 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
, addr
);
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
, addr
);
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
, start
);
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
, start
);
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
, unsigned long addr
,
381 pte_t pte
, struct page
*page
)
383 pgd_t
*pgd
= pgd_offset(vma
->vm_mm
, addr
);
384 pud_t
*pud
= pud_offset(pgd
, addr
);
385 pmd_t
*pmd
= pmd_offset(pud
, addr
);
386 struct address_space
*mapping
;
388 static unsigned long resume
;
389 static unsigned long nr_shown
;
390 static unsigned long nr_unshown
;
393 * Allow a burst of 60 reports, then keep quiet for that minute;
394 * or allow a steady drip of one report per second.
396 if (nr_shown
== 60) {
397 if (time_before(jiffies
, resume
)) {
403 "BUG: Bad page map: %lu messages suppressed\n",
410 resume
= jiffies
+ 60 * HZ
;
412 mapping
= vma
->vm_file
? vma
->vm_file
->f_mapping
: NULL
;
413 index
= linear_page_index(vma
, addr
);
416 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
418 (long long)pte_val(pte
), (long long)pmd_val(*pmd
));
421 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
422 page
, (void *)page
->flags
, page_count(page
),
423 page_mapcount(page
), page
->mapping
, page
->index
);
426 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
427 (void *)addr
, vma
->vm_flags
, vma
->anon_vma
, mapping
, index
);
429 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
432 print_symbol(KERN_ALERT
"vma->vm_ops->fault: %s\n",
433 (unsigned long)vma
->vm_ops
->fault
);
434 if (vma
->vm_file
&& vma
->vm_file
->f_op
)
435 print_symbol(KERN_ALERT
"vma->vm_file->f_op->mmap: %s\n",
436 (unsigned long)vma
->vm_file
->f_op
->mmap
);
438 add_taint(TAINT_BAD_PAGE
);
441 static inline int is_cow_mapping(unsigned int flags
)
443 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
447 * vm_normal_page -- This function gets the "struct page" associated with a pte.
449 * "Special" mappings do not wish to be associated with a "struct page" (either
450 * it doesn't exist, or it exists but they don't want to touch it). In this
451 * case, NULL is returned here. "Normal" mappings do have a struct page.
453 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
454 * pte bit, in which case this function is trivial. Secondly, an architecture
455 * may not have a spare pte bit, which requires a more complicated scheme,
458 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
459 * special mapping (even if there are underlying and valid "struct pages").
460 * COWed pages of a VM_PFNMAP are always normal.
462 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
463 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
464 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
465 * mapping will always honor the rule
467 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
469 * And for normal mappings this is false.
471 * This restricts such mappings to be a linear translation from virtual address
472 * to pfn. To get around this restriction, we allow arbitrary mappings so long
473 * as the vma is not a COW mapping; in that case, we know that all ptes are
474 * special (because none can have been COWed).
477 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
479 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
480 * page" backing, however the difference is that _all_ pages with a struct
481 * page (that is, those where pfn_valid is true) are refcounted and considered
482 * normal pages by the VM. The disadvantage is that pages are refcounted
483 * (which can be slower and simply not an option for some PFNMAP users). The
484 * advantage is that we don't have to follow the strict linearity rule of
485 * PFNMAP mappings in order to support COWable mappings.
488 #ifdef __HAVE_ARCH_PTE_SPECIAL
489 # define HAVE_PTE_SPECIAL 1
491 # define HAVE_PTE_SPECIAL 0
493 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
496 unsigned long pfn
= pte_pfn(pte
);
498 if (HAVE_PTE_SPECIAL
) {
499 if (likely(!pte_special(pte
)))
501 if (!(vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
)))
502 print_bad_pte(vma
, addr
, pte
, NULL
);
506 /* !HAVE_PTE_SPECIAL case follows: */
508 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
509 if (vma
->vm_flags
& VM_MIXEDMAP
) {
515 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
516 if (pfn
== vma
->vm_pgoff
+ off
)
518 if (!is_cow_mapping(vma
->vm_flags
))
524 if (unlikely(pfn
> highest_memmap_pfn
)) {
525 print_bad_pte(vma
, addr
, pte
, NULL
);
530 * NOTE! We still have PageReserved() pages in the page tables.
531 * eg. VDSO mappings can cause them to exist.
534 return pfn_to_page(pfn
);
538 * copy one vm_area from one task to the other. Assumes the page tables
539 * already present in the new task to be cleared in the whole range
540 * covered by this vma.
544 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
545 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
546 unsigned long addr
, int *rss
)
548 unsigned long vm_flags
= vma
->vm_flags
;
549 pte_t pte
= *src_pte
;
552 /* pte contains position in swap or file, so copy. */
553 if (unlikely(!pte_present(pte
))) {
554 if (!pte_file(pte
)) {
555 swp_entry_t entry
= pte_to_swp_entry(pte
);
557 swap_duplicate(entry
);
558 /* make sure dst_mm is on swapoff's mmlist. */
559 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
560 spin_lock(&mmlist_lock
);
561 if (list_empty(&dst_mm
->mmlist
))
562 list_add(&dst_mm
->mmlist
,
564 spin_unlock(&mmlist_lock
);
566 if (is_write_migration_entry(entry
) &&
567 is_cow_mapping(vm_flags
)) {
569 * COW mappings require pages in both parent
570 * and child to be set to read.
572 make_migration_entry_read(&entry
);
573 pte
= swp_entry_to_pte(entry
);
574 set_pte_at(src_mm
, addr
, src_pte
, pte
);
581 * If it's a COW mapping, write protect it both
582 * in the parent and the child
584 if (is_cow_mapping(vm_flags
)) {
585 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
586 pte
= pte_wrprotect(pte
);
590 * If it's a shared mapping, mark it clean in
593 if (vm_flags
& VM_SHARED
)
594 pte
= pte_mkclean(pte
);
595 pte
= pte_mkold(pte
);
597 page
= vm_normal_page(vma
, addr
, pte
);
601 rss
[!!PageAnon(page
)]++;
605 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
608 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
609 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
610 unsigned long addr
, unsigned long end
)
612 pte_t
*src_pte
, *dst_pte
;
613 spinlock_t
*src_ptl
, *dst_ptl
;
619 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
622 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
623 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
624 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
625 arch_enter_lazy_mmu_mode();
629 * We are holding two locks at this point - either of them
630 * could generate latencies in another task on another CPU.
632 if (progress
>= 32) {
634 if (need_resched() ||
635 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
638 if (pte_none(*src_pte
)) {
642 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
644 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
646 arch_leave_lazy_mmu_mode();
647 spin_unlock(src_ptl
);
648 pte_unmap_nested(src_pte
- 1);
649 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
650 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
657 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
658 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
659 unsigned long addr
, unsigned long end
)
661 pmd_t
*src_pmd
, *dst_pmd
;
664 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
667 src_pmd
= pmd_offset(src_pud
, addr
);
669 next
= pmd_addr_end(addr
, end
);
670 if (pmd_none_or_clear_bad(src_pmd
))
672 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
675 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
679 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
680 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
681 unsigned long addr
, unsigned long end
)
683 pud_t
*src_pud
, *dst_pud
;
686 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
689 src_pud
= pud_offset(src_pgd
, addr
);
691 next
= pud_addr_end(addr
, end
);
692 if (pud_none_or_clear_bad(src_pud
))
694 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
697 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
701 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
702 struct vm_area_struct
*vma
)
704 pgd_t
*src_pgd
, *dst_pgd
;
706 unsigned long addr
= vma
->vm_start
;
707 unsigned long end
= vma
->vm_end
;
711 * Don't copy ptes where a page fault will fill them correctly.
712 * Fork becomes much lighter when there are big shared or private
713 * readonly mappings. The tradeoff is that copy_page_range is more
714 * efficient than faulting.
716 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
721 if (is_vm_hugetlb_page(vma
))
722 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
724 if (unlikely(is_pfn_mapping(vma
))) {
726 * We do not free on error cases below as remove_vma
727 * gets called on error from higher level routine
729 ret
= track_pfn_vma_copy(vma
);
735 * We need to invalidate the secondary MMU mappings only when
736 * there could be a permission downgrade on the ptes of the
737 * parent mm. And a permission downgrade will only happen if
738 * is_cow_mapping() returns true.
740 if (is_cow_mapping(vma
->vm_flags
))
741 mmu_notifier_invalidate_range_start(src_mm
, addr
, end
);
744 dst_pgd
= pgd_offset(dst_mm
, addr
);
745 src_pgd
= pgd_offset(src_mm
, addr
);
747 next
= pgd_addr_end(addr
, end
);
748 if (pgd_none_or_clear_bad(src_pgd
))
750 if (unlikely(copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
755 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
757 if (is_cow_mapping(vma
->vm_flags
))
758 mmu_notifier_invalidate_range_end(src_mm
,
763 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
764 struct vm_area_struct
*vma
, pmd_t
*pmd
,
765 unsigned long addr
, unsigned long end
,
766 long *zap_work
, struct zap_details
*details
)
768 struct mm_struct
*mm
= tlb
->mm
;
774 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
775 arch_enter_lazy_mmu_mode();
778 if (pte_none(ptent
)) {
783 (*zap_work
) -= PAGE_SIZE
;
785 if (pte_present(ptent
)) {
788 page
= vm_normal_page(vma
, addr
, ptent
);
789 if (unlikely(details
) && page
) {
791 * unmap_shared_mapping_pages() wants to
792 * invalidate cache without truncating:
793 * unmap shared but keep private pages.
795 if (details
->check_mapping
&&
796 details
->check_mapping
!= page
->mapping
)
799 * Each page->index must be checked when
800 * invalidating or truncating nonlinear.
802 if (details
->nonlinear_vma
&&
803 (page
->index
< details
->first_index
||
804 page
->index
> details
->last_index
))
807 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
809 tlb_remove_tlb_entry(tlb
, pte
, addr
);
812 if (unlikely(details
) && details
->nonlinear_vma
813 && linear_page_index(details
->nonlinear_vma
,
814 addr
) != page
->index
)
815 set_pte_at(mm
, addr
, pte
,
816 pgoff_to_pte(page
->index
));
820 if (pte_dirty(ptent
))
821 set_page_dirty(page
);
822 if (pte_young(ptent
) &&
823 likely(!VM_SequentialReadHint(vma
)))
824 mark_page_accessed(page
);
827 page_remove_rmap(page
);
828 if (unlikely(page_mapcount(page
) < 0))
829 print_bad_pte(vma
, addr
, ptent
, page
);
830 tlb_remove_page(tlb
, page
);
834 * If details->check_mapping, we leave swap entries;
835 * if details->nonlinear_vma, we leave file entries.
837 if (unlikely(details
))
839 if (pte_file(ptent
)) {
840 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
)))
841 print_bad_pte(vma
, addr
, ptent
, NULL
);
843 (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent
))))
844 print_bad_pte(vma
, addr
, ptent
, NULL
);
845 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
846 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
848 add_mm_rss(mm
, file_rss
, anon_rss
);
849 arch_leave_lazy_mmu_mode();
850 pte_unmap_unlock(pte
- 1, ptl
);
855 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
856 struct vm_area_struct
*vma
, pud_t
*pud
,
857 unsigned long addr
, unsigned long end
,
858 long *zap_work
, struct zap_details
*details
)
863 pmd
= pmd_offset(pud
, addr
);
865 next
= pmd_addr_end(addr
, end
);
866 if (pmd_none_or_clear_bad(pmd
)) {
870 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
872 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
877 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
878 struct vm_area_struct
*vma
, pgd_t
*pgd
,
879 unsigned long addr
, unsigned long end
,
880 long *zap_work
, struct zap_details
*details
)
885 pud
= pud_offset(pgd
, addr
);
887 next
= pud_addr_end(addr
, end
);
888 if (pud_none_or_clear_bad(pud
)) {
892 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
894 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
899 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
900 struct vm_area_struct
*vma
,
901 unsigned long addr
, unsigned long end
,
902 long *zap_work
, struct zap_details
*details
)
907 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
911 tlb_start_vma(tlb
, vma
);
912 pgd
= pgd_offset(vma
->vm_mm
, addr
);
914 next
= pgd_addr_end(addr
, end
);
915 if (pgd_none_or_clear_bad(pgd
)) {
919 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
921 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
922 tlb_end_vma(tlb
, vma
);
927 #ifdef CONFIG_PREEMPT
928 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
930 /* No preempt: go for improved straight-line efficiency */
931 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
935 * unmap_vmas - unmap a range of memory covered by a list of vma's
936 * @tlbp: address of the caller's struct mmu_gather
937 * @vma: the starting vma
938 * @start_addr: virtual address at which to start unmapping
939 * @end_addr: virtual address at which to end unmapping
940 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
941 * @details: details of nonlinear truncation or shared cache invalidation
943 * Returns the end address of the unmapping (restart addr if interrupted).
945 * Unmap all pages in the vma list.
947 * We aim to not hold locks for too long (for scheduling latency reasons).
948 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
949 * return the ending mmu_gather to the caller.
951 * Only addresses between `start' and `end' will be unmapped.
953 * The VMA list must be sorted in ascending virtual address order.
955 * unmap_vmas() assumes that the caller will flush the whole unmapped address
956 * range after unmap_vmas() returns. So the only responsibility here is to
957 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
958 * drops the lock and schedules.
960 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
961 struct vm_area_struct
*vma
, unsigned long start_addr
,
962 unsigned long end_addr
, unsigned long *nr_accounted
,
963 struct zap_details
*details
)
965 long zap_work
= ZAP_BLOCK_SIZE
;
966 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
967 int tlb_start_valid
= 0;
968 unsigned long start
= start_addr
;
969 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
970 int fullmm
= (*tlbp
)->fullmm
;
971 struct mm_struct
*mm
= vma
->vm_mm
;
973 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
974 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
977 start
= max(vma
->vm_start
, start_addr
);
978 if (start
>= vma
->vm_end
)
980 end
= min(vma
->vm_end
, end_addr
);
981 if (end
<= vma
->vm_start
)
984 if (vma
->vm_flags
& VM_ACCOUNT
)
985 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
987 if (unlikely(is_pfn_mapping(vma
)))
988 untrack_pfn_vma(vma
, 0, 0);
990 while (start
!= end
) {
991 if (!tlb_start_valid
) {
996 if (unlikely(is_vm_hugetlb_page(vma
))) {
998 * It is undesirable to test vma->vm_file as it
999 * should be non-null for valid hugetlb area.
1000 * However, vm_file will be NULL in the error
1001 * cleanup path of do_mmap_pgoff. When
1002 * hugetlbfs ->mmap method fails,
1003 * do_mmap_pgoff() nullifies vma->vm_file
1004 * before calling this function to clean up.
1005 * Since no pte has actually been setup, it is
1006 * safe to do nothing in this case.
1009 unmap_hugepage_range(vma
, start
, end
, NULL
);
1010 zap_work
-= (end
- start
) /
1011 pages_per_huge_page(hstate_vma(vma
));
1016 start
= unmap_page_range(*tlbp
, vma
,
1017 start
, end
, &zap_work
, details
);
1020 BUG_ON(start
!= end
);
1024 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
1026 if (need_resched() ||
1027 (i_mmap_lock
&& spin_needbreak(i_mmap_lock
))) {
1035 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
1036 tlb_start_valid
= 0;
1037 zap_work
= ZAP_BLOCK_SIZE
;
1041 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
1042 return start
; /* which is now the end (or restart) address */
1046 * zap_page_range - remove user pages in a given range
1047 * @vma: vm_area_struct holding the applicable pages
1048 * @address: starting address of pages to zap
1049 * @size: number of bytes to zap
1050 * @details: details of nonlinear truncation or shared cache invalidation
1052 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
1053 unsigned long size
, struct zap_details
*details
)
1055 struct mm_struct
*mm
= vma
->vm_mm
;
1056 struct mmu_gather
*tlb
;
1057 unsigned long end
= address
+ size
;
1058 unsigned long nr_accounted
= 0;
1061 tlb
= tlb_gather_mmu(mm
, 0);
1062 update_hiwater_rss(mm
);
1063 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
1065 tlb_finish_mmu(tlb
, address
, end
);
1070 * zap_vma_ptes - remove ptes mapping the vma
1071 * @vma: vm_area_struct holding ptes to be zapped
1072 * @address: starting address of pages to zap
1073 * @size: number of bytes to zap
1075 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1077 * The entire address range must be fully contained within the vma.
1079 * Returns 0 if successful.
1081 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1084 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1085 !(vma
->vm_flags
& VM_PFNMAP
))
1087 zap_page_range(vma
, address
, size
, NULL
);
1090 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1093 * Do a quick page-table lookup for a single page.
1095 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
1104 struct mm_struct
*mm
= vma
->vm_mm
;
1106 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
1107 if (!IS_ERR(page
)) {
1108 BUG_ON(flags
& FOLL_GET
);
1113 pgd
= pgd_offset(mm
, address
);
1114 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
1117 pud
= pud_offset(pgd
, address
);
1120 if (pud_huge(*pud
)) {
1121 BUG_ON(flags
& FOLL_GET
);
1122 page
= follow_huge_pud(mm
, address
, pud
, flags
& FOLL_WRITE
);
1125 if (unlikely(pud_bad(*pud
)))
1128 pmd
= pmd_offset(pud
, address
);
1131 if (pmd_huge(*pmd
)) {
1132 BUG_ON(flags
& FOLL_GET
);
1133 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
1136 if (unlikely(pmd_bad(*pmd
)))
1139 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1142 if (!pte_present(pte
))
1144 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
1146 page
= vm_normal_page(vma
, address
, pte
);
1147 if (unlikely(!page
))
1150 if (flags
& FOLL_GET
)
1152 if (flags
& FOLL_TOUCH
) {
1153 if ((flags
& FOLL_WRITE
) &&
1154 !pte_dirty(pte
) && !PageDirty(page
))
1155 set_page_dirty(page
);
1157 * pte_mkyoung() would be more correct here, but atomic care
1158 * is needed to avoid losing the dirty bit: it is easier to use
1159 * mark_page_accessed().
1161 mark_page_accessed(page
);
1164 pte_unmap_unlock(ptep
, ptl
);
1169 pte_unmap_unlock(ptep
, ptl
);
1170 return ERR_PTR(-EFAULT
);
1173 pte_unmap_unlock(ptep
, ptl
);
1176 /* Fall through to ZERO_PAGE handling */
1179 * When core dumping an enormous anonymous area that nobody
1180 * has touched so far, we don't want to allocate page tables.
1182 if (flags
& FOLL_ANON
) {
1183 page
= ZERO_PAGE(0);
1184 if (flags
& FOLL_GET
)
1186 BUG_ON(flags
& FOLL_WRITE
);
1191 /* Can we do the FOLL_ANON optimization? */
1192 static inline int use_zero_page(struct vm_area_struct
*vma
)
1195 * We don't want to optimize FOLL_ANON for make_pages_present()
1196 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1197 * we want to get the page from the page tables to make sure
1198 * that we serialize and update with any other user of that
1201 if (vma
->vm_flags
& (VM_LOCKED
| VM_SHARED
))
1204 * And if we have a fault routine, it's not an anonymous region.
1206 return !vma
->vm_ops
|| !vma
->vm_ops
->fault
;
1211 int __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1212 unsigned long start
, int nr_pages
, int flags
,
1213 struct page
**pages
, struct vm_area_struct
**vmas
)
1216 unsigned int vm_flags
= 0;
1217 int write
= !!(flags
& GUP_FLAGS_WRITE
);
1218 int force
= !!(flags
& GUP_FLAGS_FORCE
);
1219 int ignore
= !!(flags
& GUP_FLAGS_IGNORE_VMA_PERMISSIONS
);
1220 int ignore_sigkill
= !!(flags
& GUP_FLAGS_IGNORE_SIGKILL
);
1225 * Require read or write permissions.
1226 * If 'force' is set, we only require the "MAY" flags.
1228 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1229 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1233 struct vm_area_struct
*vma
;
1234 unsigned int foll_flags
;
1236 vma
= find_extend_vma(mm
, start
);
1237 if (!vma
&& in_gate_area(tsk
, start
)) {
1238 unsigned long pg
= start
& PAGE_MASK
;
1239 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1245 /* user gate pages are read-only */
1246 if (!ignore
&& write
)
1247 return i
? : -EFAULT
;
1249 pgd
= pgd_offset_k(pg
);
1251 pgd
= pgd_offset_gate(mm
, pg
);
1252 BUG_ON(pgd_none(*pgd
));
1253 pud
= pud_offset(pgd
, pg
);
1254 BUG_ON(pud_none(*pud
));
1255 pmd
= pmd_offset(pud
, pg
);
1257 return i
? : -EFAULT
;
1258 pte
= pte_offset_map(pmd
, pg
);
1259 if (pte_none(*pte
)) {
1261 return i
? : -EFAULT
;
1264 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1279 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1280 (!ignore
&& !(vm_flags
& vma
->vm_flags
)))
1281 return i
? : -EFAULT
;
1283 if (is_vm_hugetlb_page(vma
)) {
1284 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1285 &start
, &nr_pages
, i
, write
);
1289 foll_flags
= FOLL_TOUCH
;
1291 foll_flags
|= FOLL_GET
;
1292 if (!write
&& use_zero_page(vma
))
1293 foll_flags
|= FOLL_ANON
;
1299 * If we have a pending SIGKILL, don't keep faulting
1300 * pages and potentially allocating memory, unless
1301 * current is handling munlock--e.g., on exit. In
1302 * that case, we are not allocating memory. Rather,
1303 * we're only unlocking already resident/mapped pages.
1305 if (unlikely(!ignore_sigkill
&&
1306 fatal_signal_pending(current
)))
1307 return i
? i
: -ERESTARTSYS
;
1310 foll_flags
|= FOLL_WRITE
;
1313 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1316 ret
= handle_mm_fault(mm
, vma
, start
,
1317 (foll_flags
& FOLL_WRITE
) ?
1318 FAULT_FLAG_WRITE
: 0);
1320 if (ret
& VM_FAULT_ERROR
) {
1321 if (ret
& VM_FAULT_OOM
)
1322 return i
? i
: -ENOMEM
;
1323 else if (ret
& VM_FAULT_SIGBUS
)
1324 return i
? i
: -EFAULT
;
1327 if (ret
& VM_FAULT_MAJOR
)
1333 * The VM_FAULT_WRITE bit tells us that
1334 * do_wp_page has broken COW when necessary,
1335 * even if maybe_mkwrite decided not to set
1336 * pte_write. We can thus safely do subsequent
1337 * page lookups as if they were reads. But only
1338 * do so when looping for pte_write is futile:
1339 * in some cases userspace may also be wanting
1340 * to write to the gotten user page, which a
1341 * read fault here might prevent (a readonly
1342 * page might get reCOWed by userspace write).
1344 if ((ret
& VM_FAULT_WRITE
) &&
1345 !(vma
->vm_flags
& VM_WRITE
))
1346 foll_flags
&= ~FOLL_WRITE
;
1351 return i
? i
: PTR_ERR(page
);
1355 flush_anon_page(vma
, page
, start
);
1356 flush_dcache_page(page
);
1363 } while (nr_pages
&& start
< vma
->vm_end
);
1369 * get_user_pages() - pin user pages in memory
1370 * @tsk: task_struct of target task
1371 * @mm: mm_struct of target mm
1372 * @start: starting user address
1373 * @nr_pages: number of pages from start to pin
1374 * @write: whether pages will be written to by the caller
1375 * @force: whether to force write access even if user mapping is
1376 * readonly. This will result in the page being COWed even
1377 * in MAP_SHARED mappings. You do not want this.
1378 * @pages: array that receives pointers to the pages pinned.
1379 * Should be at least nr_pages long. Or NULL, if caller
1380 * only intends to ensure the pages are faulted in.
1381 * @vmas: array of pointers to vmas corresponding to each page.
1382 * Or NULL if the caller does not require them.
1384 * Returns number of pages pinned. This may be fewer than the number
1385 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1386 * were pinned, returns -errno. Each page returned must be released
1387 * with a put_page() call when it is finished with. vmas will only
1388 * remain valid while mmap_sem is held.
1390 * Must be called with mmap_sem held for read or write.
1392 * get_user_pages walks a process's page tables and takes a reference to
1393 * each struct page that each user address corresponds to at a given
1394 * instant. That is, it takes the page that would be accessed if a user
1395 * thread accesses the given user virtual address at that instant.
1397 * This does not guarantee that the page exists in the user mappings when
1398 * get_user_pages returns, and there may even be a completely different
1399 * page there in some cases (eg. if mmapped pagecache has been invalidated
1400 * and subsequently re faulted). However it does guarantee that the page
1401 * won't be freed completely. And mostly callers simply care that the page
1402 * contains data that was valid *at some point in time*. Typically, an IO
1403 * or similar operation cannot guarantee anything stronger anyway because
1404 * locks can't be held over the syscall boundary.
1406 * If write=0, the page must not be written to. If the page is written to,
1407 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1408 * after the page is finished with, and before put_page is called.
1410 * get_user_pages is typically used for fewer-copy IO operations, to get a
1411 * handle on the memory by some means other than accesses via the user virtual
1412 * addresses. The pages may be submitted for DMA to devices or accessed via
1413 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1414 * use the correct cache flushing APIs.
1416 * See also get_user_pages_fast, for performance critical applications.
1418 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1419 unsigned long start
, int nr_pages
, int write
, int force
,
1420 struct page
**pages
, struct vm_area_struct
**vmas
)
1425 flags
|= GUP_FLAGS_WRITE
;
1427 flags
|= GUP_FLAGS_FORCE
;
1429 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
);
1432 EXPORT_SYMBOL(get_user_pages
);
1434 pte_t
*get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1437 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1438 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1440 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1442 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1448 * This is the old fallback for page remapping.
1450 * For historical reasons, it only allows reserved pages. Only
1451 * old drivers should use this, and they needed to mark their
1452 * pages reserved for the old functions anyway.
1454 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1455 struct page
*page
, pgprot_t prot
)
1457 struct mm_struct
*mm
= vma
->vm_mm
;
1466 flush_dcache_page(page
);
1467 pte
= get_locked_pte(mm
, addr
, &ptl
);
1471 if (!pte_none(*pte
))
1474 /* Ok, finally just insert the thing.. */
1476 inc_mm_counter(mm
, file_rss
);
1477 page_add_file_rmap(page
);
1478 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1481 pte_unmap_unlock(pte
, ptl
);
1484 pte_unmap_unlock(pte
, ptl
);
1490 * vm_insert_page - insert single page into user vma
1491 * @vma: user vma to map to
1492 * @addr: target user address of this page
1493 * @page: source kernel page
1495 * This allows drivers to insert individual pages they've allocated
1498 * The page has to be a nice clean _individual_ kernel allocation.
1499 * If you allocate a compound page, you need to have marked it as
1500 * such (__GFP_COMP), or manually just split the page up yourself
1501 * (see split_page()).
1503 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1504 * took an arbitrary page protection parameter. This doesn't allow
1505 * that. Your vma protection will have to be set up correctly, which
1506 * means that if you want a shared writable mapping, you'd better
1507 * ask for a shared writable mapping!
1509 * The page does not need to be reserved.
1511 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1514 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1516 if (!page_count(page
))
1518 vma
->vm_flags
|= VM_INSERTPAGE
;
1519 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1521 EXPORT_SYMBOL(vm_insert_page
);
1523 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1524 unsigned long pfn
, pgprot_t prot
)
1526 struct mm_struct
*mm
= vma
->vm_mm
;
1532 pte
= get_locked_pte(mm
, addr
, &ptl
);
1536 if (!pte_none(*pte
))
1539 /* Ok, finally just insert the thing.. */
1540 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
1541 set_pte_at(mm
, addr
, pte
, entry
);
1542 update_mmu_cache(vma
, addr
, entry
); /* XXX: why not for insert_page? */
1546 pte_unmap_unlock(pte
, ptl
);
1552 * vm_insert_pfn - insert single pfn into user vma
1553 * @vma: user vma to map to
1554 * @addr: target user address of this page
1555 * @pfn: source kernel pfn
1557 * Similar to vm_inert_page, this allows drivers to insert individual pages
1558 * they've allocated into a user vma. Same comments apply.
1560 * This function should only be called from a vm_ops->fault handler, and
1561 * in that case the handler should return NULL.
1563 * vma cannot be a COW mapping.
1565 * As this is called only for pages that do not currently exist, we
1566 * do not need to flush old virtual caches or the TLB.
1568 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1572 pgprot_t pgprot
= vma
->vm_page_prot
;
1574 * Technically, architectures with pte_special can avoid all these
1575 * restrictions (same for remap_pfn_range). However we would like
1576 * consistency in testing and feature parity among all, so we should
1577 * try to keep these invariants in place for everybody.
1579 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1580 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1581 (VM_PFNMAP
|VM_MIXEDMAP
));
1582 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1583 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1585 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1587 if (track_pfn_vma_new(vma
, &pgprot
, pfn
, PAGE_SIZE
))
1590 ret
= insert_pfn(vma
, addr
, pfn
, pgprot
);
1593 untrack_pfn_vma(vma
, pfn
, PAGE_SIZE
);
1597 EXPORT_SYMBOL(vm_insert_pfn
);
1599 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1602 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1604 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1608 * If we don't have pte special, then we have to use the pfn_valid()
1609 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1610 * refcount the page if pfn_valid is true (hence insert_page rather
1613 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
1616 page
= pfn_to_page(pfn
);
1617 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1619 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1621 EXPORT_SYMBOL(vm_insert_mixed
);
1624 * maps a range of physical memory into the requested pages. the old
1625 * mappings are removed. any references to nonexistent pages results
1626 * in null mappings (currently treated as "copy-on-access")
1628 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1629 unsigned long addr
, unsigned long end
,
1630 unsigned long pfn
, pgprot_t prot
)
1635 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1638 arch_enter_lazy_mmu_mode();
1640 BUG_ON(!pte_none(*pte
));
1641 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1643 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1644 arch_leave_lazy_mmu_mode();
1645 pte_unmap_unlock(pte
- 1, ptl
);
1649 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1650 unsigned long addr
, unsigned long end
,
1651 unsigned long pfn
, pgprot_t prot
)
1656 pfn
-= addr
>> PAGE_SHIFT
;
1657 pmd
= pmd_alloc(mm
, pud
, addr
);
1661 next
= pmd_addr_end(addr
, end
);
1662 if (remap_pte_range(mm
, pmd
, addr
, next
,
1663 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1665 } while (pmd
++, addr
= next
, addr
!= end
);
1669 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1670 unsigned long addr
, unsigned long end
,
1671 unsigned long pfn
, pgprot_t prot
)
1676 pfn
-= addr
>> PAGE_SHIFT
;
1677 pud
= pud_alloc(mm
, pgd
, addr
);
1681 next
= pud_addr_end(addr
, end
);
1682 if (remap_pmd_range(mm
, pud
, addr
, next
,
1683 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1685 } while (pud
++, addr
= next
, addr
!= end
);
1690 * remap_pfn_range - remap kernel memory to userspace
1691 * @vma: user vma to map to
1692 * @addr: target user address to start at
1693 * @pfn: physical address of kernel memory
1694 * @size: size of map area
1695 * @prot: page protection flags for this mapping
1697 * Note: this is only safe if the mm semaphore is held when called.
1699 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1700 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1704 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1705 struct mm_struct
*mm
= vma
->vm_mm
;
1709 * Physically remapped pages are special. Tell the
1710 * rest of the world about it:
1711 * VM_IO tells people not to look at these pages
1712 * (accesses can have side effects).
1713 * VM_RESERVED is specified all over the place, because
1714 * in 2.4 it kept swapout's vma scan off this vma; but
1715 * in 2.6 the LRU scan won't even find its pages, so this
1716 * flag means no more than count its pages in reserved_vm,
1717 * and omit it from core dump, even when VM_IO turned off.
1718 * VM_PFNMAP tells the core MM that the base pages are just
1719 * raw PFN mappings, and do not have a "struct page" associated
1722 * There's a horrible special case to handle copy-on-write
1723 * behaviour that some programs depend on. We mark the "original"
1724 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1726 if (addr
== vma
->vm_start
&& end
== vma
->vm_end
) {
1727 vma
->vm_pgoff
= pfn
;
1728 vma
->vm_flags
|= VM_PFN_AT_MMAP
;
1729 } else if (is_cow_mapping(vma
->vm_flags
))
1732 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1734 err
= track_pfn_vma_new(vma
, &prot
, pfn
, PAGE_ALIGN(size
));
1737 * To indicate that track_pfn related cleanup is not
1738 * needed from higher level routine calling unmap_vmas
1740 vma
->vm_flags
&= ~(VM_IO
| VM_RESERVED
| VM_PFNMAP
);
1741 vma
->vm_flags
&= ~VM_PFN_AT_MMAP
;
1745 BUG_ON(addr
>= end
);
1746 pfn
-= addr
>> PAGE_SHIFT
;
1747 pgd
= pgd_offset(mm
, addr
);
1748 flush_cache_range(vma
, addr
, end
);
1750 next
= pgd_addr_end(addr
, end
);
1751 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1752 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1755 } while (pgd
++, addr
= next
, addr
!= end
);
1758 untrack_pfn_vma(vma
, pfn
, PAGE_ALIGN(size
));
1762 EXPORT_SYMBOL(remap_pfn_range
);
1764 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1765 unsigned long addr
, unsigned long end
,
1766 pte_fn_t fn
, void *data
)
1771 spinlock_t
*uninitialized_var(ptl
);
1773 pte
= (mm
== &init_mm
) ?
1774 pte_alloc_kernel(pmd
, addr
) :
1775 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1779 BUG_ON(pmd_huge(*pmd
));
1781 arch_enter_lazy_mmu_mode();
1783 token
= pmd_pgtable(*pmd
);
1786 err
= fn(pte
, token
, addr
, data
);
1789 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1791 arch_leave_lazy_mmu_mode();
1794 pte_unmap_unlock(pte
-1, ptl
);
1798 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1799 unsigned long addr
, unsigned long end
,
1800 pte_fn_t fn
, void *data
)
1806 BUG_ON(pud_huge(*pud
));
1808 pmd
= pmd_alloc(mm
, pud
, addr
);
1812 next
= pmd_addr_end(addr
, end
);
1813 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1816 } while (pmd
++, addr
= next
, addr
!= end
);
1820 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1821 unsigned long addr
, unsigned long end
,
1822 pte_fn_t fn
, void *data
)
1828 pud
= pud_alloc(mm
, pgd
, addr
);
1832 next
= pud_addr_end(addr
, end
);
1833 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1836 } while (pud
++, addr
= next
, addr
!= end
);
1841 * Scan a region of virtual memory, filling in page tables as necessary
1842 * and calling a provided function on each leaf page table.
1844 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1845 unsigned long size
, pte_fn_t fn
, void *data
)
1849 unsigned long start
= addr
, end
= addr
+ size
;
1852 BUG_ON(addr
>= end
);
1853 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1854 pgd
= pgd_offset(mm
, addr
);
1856 next
= pgd_addr_end(addr
, end
);
1857 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1860 } while (pgd
++, addr
= next
, addr
!= end
);
1861 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1864 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1867 * handle_pte_fault chooses page fault handler according to an entry
1868 * which was read non-atomically. Before making any commitment, on
1869 * those architectures or configurations (e.g. i386 with PAE) which
1870 * might give a mix of unmatched parts, do_swap_page and do_file_page
1871 * must check under lock before unmapping the pte and proceeding
1872 * (but do_wp_page is only called after already making such a check;
1873 * and do_anonymous_page and do_no_page can safely check later on).
1875 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1876 pte_t
*page_table
, pte_t orig_pte
)
1879 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1880 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1881 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1883 same
= pte_same(*page_table
, orig_pte
);
1887 pte_unmap(page_table
);
1892 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1893 * servicing faults for write access. In the normal case, do always want
1894 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1895 * that do not have writing enabled, when used by access_process_vm.
1897 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1899 if (likely(vma
->vm_flags
& VM_WRITE
))
1900 pte
= pte_mkwrite(pte
);
1904 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1907 * If the source page was a PFN mapping, we don't have
1908 * a "struct page" for it. We do a best-effort copy by
1909 * just copying from the original user address. If that
1910 * fails, we just zero-fill it. Live with it.
1912 if (unlikely(!src
)) {
1913 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1914 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1917 * This really shouldn't fail, because the page is there
1918 * in the page tables. But it might just be unreadable,
1919 * in which case we just give up and fill the result with
1922 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1923 memset(kaddr
, 0, PAGE_SIZE
);
1924 kunmap_atomic(kaddr
, KM_USER0
);
1925 flush_dcache_page(dst
);
1927 copy_user_highpage(dst
, src
, va
, vma
);
1931 * This routine handles present pages, when users try to write
1932 * to a shared page. It is done by copying the page to a new address
1933 * and decrementing the shared-page counter for the old page.
1935 * Note that this routine assumes that the protection checks have been
1936 * done by the caller (the low-level page fault routine in most cases).
1937 * Thus we can safely just mark it writable once we've done any necessary
1940 * We also mark the page dirty at this point even though the page will
1941 * change only once the write actually happens. This avoids a few races,
1942 * and potentially makes it more efficient.
1944 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1945 * but allow concurrent faults), with pte both mapped and locked.
1946 * We return with mmap_sem still held, but pte unmapped and unlocked.
1948 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1949 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1950 spinlock_t
*ptl
, pte_t orig_pte
)
1952 struct page
*old_page
, *new_page
;
1954 int reuse
= 0, ret
= 0;
1955 int page_mkwrite
= 0;
1956 struct page
*dirty_page
= NULL
;
1958 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1961 * VM_MIXEDMAP !pfn_valid() case
1963 * We should not cow pages in a shared writeable mapping.
1964 * Just mark the pages writable as we can't do any dirty
1965 * accounting on raw pfn maps.
1967 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1968 (VM_WRITE
|VM_SHARED
))
1974 * Take out anonymous pages first, anonymous shared vmas are
1975 * not dirty accountable.
1977 if (PageAnon(old_page
)) {
1978 if (!trylock_page(old_page
)) {
1979 page_cache_get(old_page
);
1980 pte_unmap_unlock(page_table
, ptl
);
1981 lock_page(old_page
);
1982 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1984 if (!pte_same(*page_table
, orig_pte
)) {
1985 unlock_page(old_page
);
1986 page_cache_release(old_page
);
1989 page_cache_release(old_page
);
1991 reuse
= reuse_swap_page(old_page
);
1992 unlock_page(old_page
);
1993 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1994 (VM_WRITE
|VM_SHARED
))) {
1996 * Only catch write-faults on shared writable pages,
1997 * read-only shared pages can get COWed by
1998 * get_user_pages(.write=1, .force=1).
2000 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
2001 struct vm_fault vmf
;
2004 vmf
.virtual_address
= (void __user
*)(address
&
2006 vmf
.pgoff
= old_page
->index
;
2007 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2008 vmf
.page
= old_page
;
2011 * Notify the address space that the page is about to
2012 * become writable so that it can prohibit this or wait
2013 * for the page to get into an appropriate state.
2015 * We do this without the lock held, so that it can
2016 * sleep if it needs to.
2018 page_cache_get(old_page
);
2019 pte_unmap_unlock(page_table
, ptl
);
2021 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2023 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2025 goto unwritable_page
;
2027 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2028 lock_page(old_page
);
2029 if (!old_page
->mapping
) {
2030 ret
= 0; /* retry the fault */
2031 unlock_page(old_page
);
2032 goto unwritable_page
;
2035 VM_BUG_ON(!PageLocked(old_page
));
2038 * Since we dropped the lock we need to revalidate
2039 * the PTE as someone else may have changed it. If
2040 * they did, we just return, as we can count on the
2041 * MMU to tell us if they didn't also make it writable.
2043 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
2045 if (!pte_same(*page_table
, orig_pte
)) {
2046 unlock_page(old_page
);
2047 page_cache_release(old_page
);
2053 dirty_page
= old_page
;
2054 get_page(dirty_page
);
2060 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2061 entry
= pte_mkyoung(orig_pte
);
2062 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2063 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
2064 update_mmu_cache(vma
, address
, entry
);
2065 ret
|= VM_FAULT_WRITE
;
2070 * Ok, we need to copy. Oh, well..
2072 page_cache_get(old_page
);
2074 pte_unmap_unlock(page_table
, ptl
);
2076 if (unlikely(anon_vma_prepare(vma
)))
2078 VM_BUG_ON(old_page
== ZERO_PAGE(0));
2079 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
2083 * Don't let another task, with possibly unlocked vma,
2084 * keep the mlocked page.
2086 if ((vma
->vm_flags
& VM_LOCKED
) && old_page
) {
2087 lock_page(old_page
); /* for LRU manipulation */
2088 clear_page_mlock(old_page
);
2089 unlock_page(old_page
);
2091 cow_user_page(new_page
, old_page
, address
, vma
);
2092 __SetPageUptodate(new_page
);
2094 if (mem_cgroup_newpage_charge(new_page
, mm
, GFP_KERNEL
))
2098 * Re-check the pte - we dropped the lock
2100 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2101 if (likely(pte_same(*page_table
, orig_pte
))) {
2103 if (!PageAnon(old_page
)) {
2104 dec_mm_counter(mm
, file_rss
);
2105 inc_mm_counter(mm
, anon_rss
);
2108 inc_mm_counter(mm
, anon_rss
);
2109 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2110 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2111 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2113 * Clear the pte entry and flush it first, before updating the
2114 * pte with the new entry. This will avoid a race condition
2115 * seen in the presence of one thread doing SMC and another
2118 ptep_clear_flush(vma
, address
, page_table
);
2119 page_add_new_anon_rmap(new_page
, vma
, address
);
2121 * We call the notify macro here because, when using secondary
2122 * mmu page tables (such as kvm shadow page tables), we want the
2123 * new page to be mapped directly into the secondary page table.
2125 set_pte_at_notify(mm
, address
, page_table
, entry
);
2126 update_mmu_cache(vma
, address
, entry
);
2129 * Only after switching the pte to the new page may
2130 * we remove the mapcount here. Otherwise another
2131 * process may come and find the rmap count decremented
2132 * before the pte is switched to the new page, and
2133 * "reuse" the old page writing into it while our pte
2134 * here still points into it and can be read by other
2137 * The critical issue is to order this
2138 * page_remove_rmap with the ptp_clear_flush above.
2139 * Those stores are ordered by (if nothing else,)
2140 * the barrier present in the atomic_add_negative
2141 * in page_remove_rmap.
2143 * Then the TLB flush in ptep_clear_flush ensures that
2144 * no process can access the old page before the
2145 * decremented mapcount is visible. And the old page
2146 * cannot be reused until after the decremented
2147 * mapcount is visible. So transitively, TLBs to
2148 * old page will be flushed before it can be reused.
2150 page_remove_rmap(old_page
);
2153 /* Free the old page.. */
2154 new_page
= old_page
;
2155 ret
|= VM_FAULT_WRITE
;
2157 mem_cgroup_uncharge_page(new_page
);
2160 page_cache_release(new_page
);
2162 page_cache_release(old_page
);
2164 pte_unmap_unlock(page_table
, ptl
);
2167 * Yes, Virginia, this is actually required to prevent a race
2168 * with clear_page_dirty_for_io() from clearing the page dirty
2169 * bit after it clear all dirty ptes, but before a racing
2170 * do_wp_page installs a dirty pte.
2172 * do_no_page is protected similarly.
2174 if (!page_mkwrite
) {
2175 wait_on_page_locked(dirty_page
);
2176 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2178 put_page(dirty_page
);
2180 struct address_space
*mapping
= dirty_page
->mapping
;
2182 set_page_dirty(dirty_page
);
2183 unlock_page(dirty_page
);
2184 page_cache_release(dirty_page
);
2187 * Some device drivers do not set page.mapping
2188 * but still dirty their pages
2190 balance_dirty_pages_ratelimited(mapping
);
2194 /* file_update_time outside page_lock */
2196 file_update_time(vma
->vm_file
);
2200 page_cache_release(new_page
);
2204 unlock_page(old_page
);
2205 page_cache_release(old_page
);
2207 page_cache_release(old_page
);
2209 return VM_FAULT_OOM
;
2212 page_cache_release(old_page
);
2217 * Helper functions for unmap_mapping_range().
2219 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2221 * We have to restart searching the prio_tree whenever we drop the lock,
2222 * since the iterator is only valid while the lock is held, and anyway
2223 * a later vma might be split and reinserted earlier while lock dropped.
2225 * The list of nonlinear vmas could be handled more efficiently, using
2226 * a placeholder, but handle it in the same way until a need is shown.
2227 * It is important to search the prio_tree before nonlinear list: a vma
2228 * may become nonlinear and be shifted from prio_tree to nonlinear list
2229 * while the lock is dropped; but never shifted from list to prio_tree.
2231 * In order to make forward progress despite restarting the search,
2232 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2233 * quickly skip it next time around. Since the prio_tree search only
2234 * shows us those vmas affected by unmapping the range in question, we
2235 * can't efficiently keep all vmas in step with mapping->truncate_count:
2236 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2237 * mapping->truncate_count and vma->vm_truncate_count are protected by
2240 * In order to make forward progress despite repeatedly restarting some
2241 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2242 * and restart from that address when we reach that vma again. It might
2243 * have been split or merged, shrunk or extended, but never shifted: so
2244 * restart_addr remains valid so long as it remains in the vma's range.
2245 * unmap_mapping_range forces truncate_count to leap over page-aligned
2246 * values so we can save vma's restart_addr in its truncate_count field.
2248 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2250 static void reset_vma_truncate_counts(struct address_space
*mapping
)
2252 struct vm_area_struct
*vma
;
2253 struct prio_tree_iter iter
;
2255 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
2256 vma
->vm_truncate_count
= 0;
2257 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
2258 vma
->vm_truncate_count
= 0;
2261 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2262 unsigned long start_addr
, unsigned long end_addr
,
2263 struct zap_details
*details
)
2265 unsigned long restart_addr
;
2269 * files that support invalidating or truncating portions of the
2270 * file from under mmaped areas must have their ->fault function
2271 * return a locked page (and set VM_FAULT_LOCKED in the return).
2272 * This provides synchronisation against concurrent unmapping here.
2276 restart_addr
= vma
->vm_truncate_count
;
2277 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
2278 start_addr
= restart_addr
;
2279 if (start_addr
>= end_addr
) {
2280 /* Top of vma has been split off since last time */
2281 vma
->vm_truncate_count
= details
->truncate_count
;
2286 restart_addr
= zap_page_range(vma
, start_addr
,
2287 end_addr
- start_addr
, details
);
2288 need_break
= need_resched() || spin_needbreak(details
->i_mmap_lock
);
2290 if (restart_addr
>= end_addr
) {
2291 /* We have now completed this vma: mark it so */
2292 vma
->vm_truncate_count
= details
->truncate_count
;
2296 /* Note restart_addr in vma's truncate_count field */
2297 vma
->vm_truncate_count
= restart_addr
;
2302 spin_unlock(details
->i_mmap_lock
);
2304 spin_lock(details
->i_mmap_lock
);
2308 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
2309 struct zap_details
*details
)
2311 struct vm_area_struct
*vma
;
2312 struct prio_tree_iter iter
;
2313 pgoff_t vba
, vea
, zba
, zea
;
2316 vma_prio_tree_foreach(vma
, &iter
, root
,
2317 details
->first_index
, details
->last_index
) {
2318 /* Skip quickly over those we have already dealt with */
2319 if (vma
->vm_truncate_count
== details
->truncate_count
)
2322 vba
= vma
->vm_pgoff
;
2323 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
2324 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2325 zba
= details
->first_index
;
2328 zea
= details
->last_index
;
2332 if (unmap_mapping_range_vma(vma
,
2333 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2334 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2340 static inline void unmap_mapping_range_list(struct list_head
*head
,
2341 struct zap_details
*details
)
2343 struct vm_area_struct
*vma
;
2346 * In nonlinear VMAs there is no correspondence between virtual address
2347 * offset and file offset. So we must perform an exhaustive search
2348 * across *all* the pages in each nonlinear VMA, not just the pages
2349 * whose virtual address lies outside the file truncation point.
2352 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
2353 /* Skip quickly over those we have already dealt with */
2354 if (vma
->vm_truncate_count
== details
->truncate_count
)
2356 details
->nonlinear_vma
= vma
;
2357 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
2358 vma
->vm_end
, details
) < 0)
2364 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2365 * @mapping: the address space containing mmaps to be unmapped.
2366 * @holebegin: byte in first page to unmap, relative to the start of
2367 * the underlying file. This will be rounded down to a PAGE_SIZE
2368 * boundary. Note that this is different from vmtruncate(), which
2369 * must keep the partial page. In contrast, we must get rid of
2371 * @holelen: size of prospective hole in bytes. This will be rounded
2372 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2374 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2375 * but 0 when invalidating pagecache, don't throw away private data.
2377 void unmap_mapping_range(struct address_space
*mapping
,
2378 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2380 struct zap_details details
;
2381 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2382 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2384 /* Check for overflow. */
2385 if (sizeof(holelen
) > sizeof(hlen
)) {
2387 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2388 if (holeend
& ~(long long)ULONG_MAX
)
2389 hlen
= ULONG_MAX
- hba
+ 1;
2392 details
.check_mapping
= even_cows
? NULL
: mapping
;
2393 details
.nonlinear_vma
= NULL
;
2394 details
.first_index
= hba
;
2395 details
.last_index
= hba
+ hlen
- 1;
2396 if (details
.last_index
< details
.first_index
)
2397 details
.last_index
= ULONG_MAX
;
2398 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
2400 spin_lock(&mapping
->i_mmap_lock
);
2402 /* Protect against endless unmapping loops */
2403 mapping
->truncate_count
++;
2404 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
2405 if (mapping
->truncate_count
== 0)
2406 reset_vma_truncate_counts(mapping
);
2407 mapping
->truncate_count
++;
2409 details
.truncate_count
= mapping
->truncate_count
;
2411 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
2412 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2413 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2414 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2415 spin_unlock(&mapping
->i_mmap_lock
);
2417 EXPORT_SYMBOL(unmap_mapping_range
);
2420 * vmtruncate - unmap mappings "freed" by truncate() syscall
2421 * @inode: inode of the file used
2422 * @offset: file offset to start truncating
2424 * NOTE! We have to be ready to update the memory sharing
2425 * between the file and the memory map for a potential last
2426 * incomplete page. Ugly, but necessary.
2428 int vmtruncate(struct inode
* inode
, loff_t offset
)
2430 if (inode
->i_size
< offset
) {
2431 unsigned long limit
;
2433 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2434 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2436 if (offset
> inode
->i_sb
->s_maxbytes
)
2438 i_size_write(inode
, offset
);
2440 struct address_space
*mapping
= inode
->i_mapping
;
2443 * truncation of in-use swapfiles is disallowed - it would
2444 * cause subsequent swapout to scribble on the now-freed
2447 if (IS_SWAPFILE(inode
))
2449 i_size_write(inode
, offset
);
2452 * unmap_mapping_range is called twice, first simply for
2453 * efficiency so that truncate_inode_pages does fewer
2454 * single-page unmaps. However after this first call, and
2455 * before truncate_inode_pages finishes, it is possible for
2456 * private pages to be COWed, which remain after
2457 * truncate_inode_pages finishes, hence the second
2458 * unmap_mapping_range call must be made for correctness.
2460 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2461 truncate_inode_pages(mapping
, offset
);
2462 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2465 if (inode
->i_op
->truncate
)
2466 inode
->i_op
->truncate(inode
);
2470 send_sig(SIGXFSZ
, current
, 0);
2474 EXPORT_SYMBOL(vmtruncate
);
2476 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2478 struct address_space
*mapping
= inode
->i_mapping
;
2481 * If the underlying filesystem is not going to provide
2482 * a way to truncate a range of blocks (punch a hole) -
2483 * we should return failure right now.
2485 if (!inode
->i_op
->truncate_range
)
2488 mutex_lock(&inode
->i_mutex
);
2489 down_write(&inode
->i_alloc_sem
);
2490 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2491 truncate_inode_pages_range(mapping
, offset
, end
);
2492 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2493 inode
->i_op
->truncate_range(inode
, offset
, end
);
2494 up_write(&inode
->i_alloc_sem
);
2495 mutex_unlock(&inode
->i_mutex
);
2501 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2502 * but allow concurrent faults), and pte mapped but not yet locked.
2503 * We return with mmap_sem still held, but pte unmapped and unlocked.
2505 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2506 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2507 unsigned int flags
, pte_t orig_pte
)
2513 struct mem_cgroup
*ptr
= NULL
;
2516 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2519 entry
= pte_to_swp_entry(orig_pte
);
2520 if (is_migration_entry(entry
)) {
2521 migration_entry_wait(mm
, pmd
, address
);
2524 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2525 page
= lookup_swap_cache(entry
);
2527 grab_swap_token(mm
); /* Contend for token _before_ read-in */
2528 page
= swapin_readahead(entry
,
2529 GFP_HIGHUSER_MOVABLE
, vma
, address
);
2532 * Back out if somebody else faulted in this pte
2533 * while we released the pte lock.
2535 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2536 if (likely(pte_same(*page_table
, orig_pte
)))
2538 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2542 /* Had to read the page from swap area: Major fault */
2543 ret
= VM_FAULT_MAJOR
;
2544 count_vm_event(PGMAJFAULT
);
2548 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2550 if (mem_cgroup_try_charge_swapin(mm
, page
, GFP_KERNEL
, &ptr
)) {
2556 * Back out if somebody else already faulted in this pte.
2558 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2559 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2562 if (unlikely(!PageUptodate(page
))) {
2563 ret
= VM_FAULT_SIGBUS
;
2568 * The page isn't present yet, go ahead with the fault.
2570 * Be careful about the sequence of operations here.
2571 * To get its accounting right, reuse_swap_page() must be called
2572 * while the page is counted on swap but not yet in mapcount i.e.
2573 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2574 * must be called after the swap_free(), or it will never succeed.
2575 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2576 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2577 * in page->private. In this case, a record in swap_cgroup is silently
2578 * discarded at swap_free().
2581 inc_mm_counter(mm
, anon_rss
);
2582 pte
= mk_pte(page
, vma
->vm_page_prot
);
2583 if ((flags
& FAULT_FLAG_WRITE
) && reuse_swap_page(page
)) {
2584 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2585 flags
&= ~FAULT_FLAG_WRITE
;
2587 flush_icache_page(vma
, page
);
2588 set_pte_at(mm
, address
, page_table
, pte
);
2589 page_add_anon_rmap(page
, vma
, address
);
2590 /* It's better to call commit-charge after rmap is established */
2591 mem_cgroup_commit_charge_swapin(page
, ptr
);
2594 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
2595 try_to_free_swap(page
);
2598 if (flags
& FAULT_FLAG_WRITE
) {
2599 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
2600 if (ret
& VM_FAULT_ERROR
)
2601 ret
&= VM_FAULT_ERROR
;
2605 /* No need to invalidate - it was non-present before */
2606 update_mmu_cache(vma
, address
, pte
);
2608 pte_unmap_unlock(page_table
, ptl
);
2612 mem_cgroup_cancel_charge_swapin(ptr
);
2613 pte_unmap_unlock(page_table
, ptl
);
2616 page_cache_release(page
);
2621 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2622 * but allow concurrent faults), and pte mapped but not yet locked.
2623 * We return with mmap_sem still held, but pte unmapped and unlocked.
2625 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2626 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2633 /* Allocate our own private page. */
2634 pte_unmap(page_table
);
2636 if (unlikely(anon_vma_prepare(vma
)))
2638 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2641 __SetPageUptodate(page
);
2643 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
))
2646 entry
= mk_pte(page
, vma
->vm_page_prot
);
2647 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2649 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2650 if (!pte_none(*page_table
))
2652 inc_mm_counter(mm
, anon_rss
);
2653 page_add_new_anon_rmap(page
, vma
, address
);
2654 set_pte_at(mm
, address
, page_table
, entry
);
2656 /* No need to invalidate - it was non-present before */
2657 update_mmu_cache(vma
, address
, entry
);
2659 pte_unmap_unlock(page_table
, ptl
);
2662 mem_cgroup_uncharge_page(page
);
2663 page_cache_release(page
);
2666 page_cache_release(page
);
2668 return VM_FAULT_OOM
;
2672 * __do_fault() tries to create a new page mapping. It aggressively
2673 * tries to share with existing pages, but makes a separate copy if
2674 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2675 * the next page fault.
2677 * As this is called only for pages that do not currently exist, we
2678 * do not need to flush old virtual caches or the TLB.
2680 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2681 * but allow concurrent faults), and pte neither mapped nor locked.
2682 * We return with mmap_sem still held, but pte unmapped and unlocked.
2684 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2685 unsigned long address
, pmd_t
*pmd
,
2686 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2694 struct page
*dirty_page
= NULL
;
2695 struct vm_fault vmf
;
2697 int page_mkwrite
= 0;
2699 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2704 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2705 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2709 * For consistency in subsequent calls, make the faulted page always
2712 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2713 lock_page(vmf
.page
);
2715 VM_BUG_ON(!PageLocked(vmf
.page
));
2718 * Should we do an early C-O-W break?
2721 if (flags
& FAULT_FLAG_WRITE
) {
2722 if (!(vma
->vm_flags
& VM_SHARED
)) {
2724 if (unlikely(anon_vma_prepare(vma
))) {
2728 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2734 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
)) {
2736 page_cache_release(page
);
2741 * Don't let another task, with possibly unlocked vma,
2742 * keep the mlocked page.
2744 if (vma
->vm_flags
& VM_LOCKED
)
2745 clear_page_mlock(vmf
.page
);
2746 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2747 __SetPageUptodate(page
);
2750 * If the page will be shareable, see if the backing
2751 * address space wants to know that the page is about
2752 * to become writable
2754 if (vma
->vm_ops
->page_mkwrite
) {
2758 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2759 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2761 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2763 goto unwritable_page
;
2765 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2767 if (!page
->mapping
) {
2768 ret
= 0; /* retry the fault */
2770 goto unwritable_page
;
2773 VM_BUG_ON(!PageLocked(page
));
2780 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2783 * This silly early PAGE_DIRTY setting removes a race
2784 * due to the bad i386 page protection. But it's valid
2785 * for other architectures too.
2787 * Note that if FAULT_FLAG_WRITE is set, we either now have
2788 * an exclusive copy of the page, or this is a shared mapping,
2789 * so we can make it writable and dirty to avoid having to
2790 * handle that later.
2792 /* Only go through if we didn't race with anybody else... */
2793 if (likely(pte_same(*page_table
, orig_pte
))) {
2794 flush_icache_page(vma
, page
);
2795 entry
= mk_pte(page
, vma
->vm_page_prot
);
2796 if (flags
& FAULT_FLAG_WRITE
)
2797 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2799 inc_mm_counter(mm
, anon_rss
);
2800 page_add_new_anon_rmap(page
, vma
, address
);
2802 inc_mm_counter(mm
, file_rss
);
2803 page_add_file_rmap(page
);
2804 if (flags
& FAULT_FLAG_WRITE
) {
2806 get_page(dirty_page
);
2809 set_pte_at(mm
, address
, page_table
, entry
);
2811 /* no need to invalidate: a not-present page won't be cached */
2812 update_mmu_cache(vma
, address
, entry
);
2815 mem_cgroup_uncharge_page(page
);
2817 page_cache_release(page
);
2819 anon
= 1; /* no anon but release faulted_page */
2822 pte_unmap_unlock(page_table
, ptl
);
2826 struct address_space
*mapping
= page
->mapping
;
2828 if (set_page_dirty(dirty_page
))
2830 unlock_page(dirty_page
);
2831 put_page(dirty_page
);
2832 if (page_mkwrite
&& mapping
) {
2834 * Some device drivers do not set page.mapping but still
2837 balance_dirty_pages_ratelimited(mapping
);
2840 /* file_update_time outside page_lock */
2842 file_update_time(vma
->vm_file
);
2844 unlock_page(vmf
.page
);
2846 page_cache_release(vmf
.page
);
2852 page_cache_release(page
);
2856 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2857 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2858 unsigned int flags
, pte_t orig_pte
)
2860 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2861 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2863 pte_unmap(page_table
);
2864 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2868 * Fault of a previously existing named mapping. Repopulate the pte
2869 * from the encoded file_pte if possible. This enables swappable
2872 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2873 * but allow concurrent faults), and pte mapped but not yet locked.
2874 * We return with mmap_sem still held, but pte unmapped and unlocked.
2876 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2877 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2878 unsigned int flags
, pte_t orig_pte
)
2882 flags
|= FAULT_FLAG_NONLINEAR
;
2884 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2887 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
2889 * Page table corrupted: show pte and kill process.
2891 print_bad_pte(vma
, address
, orig_pte
, NULL
);
2892 return VM_FAULT_OOM
;
2895 pgoff
= pte_to_pgoff(orig_pte
);
2896 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2900 * These routines also need to handle stuff like marking pages dirty
2901 * and/or accessed for architectures that don't do it in hardware (most
2902 * RISC architectures). The early dirtying is also good on the i386.
2904 * There is also a hook called "update_mmu_cache()" that architectures
2905 * with external mmu caches can use to update those (ie the Sparc or
2906 * PowerPC hashed page tables that act as extended TLBs).
2908 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2909 * but allow concurrent faults), and pte mapped but not yet locked.
2910 * We return with mmap_sem still held, but pte unmapped and unlocked.
2912 static inline int handle_pte_fault(struct mm_struct
*mm
,
2913 struct vm_area_struct
*vma
, unsigned long address
,
2914 pte_t
*pte
, pmd_t
*pmd
, unsigned int flags
)
2920 if (!pte_present(entry
)) {
2921 if (pte_none(entry
)) {
2923 if (likely(vma
->vm_ops
->fault
))
2924 return do_linear_fault(mm
, vma
, address
,
2925 pte
, pmd
, flags
, entry
);
2927 return do_anonymous_page(mm
, vma
, address
,
2930 if (pte_file(entry
))
2931 return do_nonlinear_fault(mm
, vma
, address
,
2932 pte
, pmd
, flags
, entry
);
2933 return do_swap_page(mm
, vma
, address
,
2934 pte
, pmd
, flags
, entry
);
2937 ptl
= pte_lockptr(mm
, pmd
);
2939 if (unlikely(!pte_same(*pte
, entry
)))
2941 if (flags
& FAULT_FLAG_WRITE
) {
2942 if (!pte_write(entry
))
2943 return do_wp_page(mm
, vma
, address
,
2944 pte
, pmd
, ptl
, entry
);
2945 entry
= pte_mkdirty(entry
);
2947 entry
= pte_mkyoung(entry
);
2948 if (ptep_set_access_flags(vma
, address
, pte
, entry
, flags
& FAULT_FLAG_WRITE
)) {
2949 update_mmu_cache(vma
, address
, entry
);
2952 * This is needed only for protection faults but the arch code
2953 * is not yet telling us if this is a protection fault or not.
2954 * This still avoids useless tlb flushes for .text page faults
2957 if (flags
& FAULT_FLAG_WRITE
)
2958 flush_tlb_page(vma
, address
);
2961 pte_unmap_unlock(pte
, ptl
);
2966 * By the time we get here, we already hold the mm semaphore
2968 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2969 unsigned long address
, unsigned int flags
)
2976 __set_current_state(TASK_RUNNING
);
2978 count_vm_event(PGFAULT
);
2980 if (unlikely(is_vm_hugetlb_page(vma
)))
2981 return hugetlb_fault(mm
, vma
, address
, flags
);
2983 pgd
= pgd_offset(mm
, address
);
2984 pud
= pud_alloc(mm
, pgd
, address
);
2986 return VM_FAULT_OOM
;
2987 pmd
= pmd_alloc(mm
, pud
, address
);
2989 return VM_FAULT_OOM
;
2990 pte
= pte_alloc_map(mm
, pmd
, address
);
2992 return VM_FAULT_OOM
;
2994 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, flags
);
2997 #ifndef __PAGETABLE_PUD_FOLDED
2999 * Allocate page upper directory.
3000 * We've already handled the fast-path in-line.
3002 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
3004 pud_t
*new = pud_alloc_one(mm
, address
);
3008 smp_wmb(); /* See comment in __pte_alloc */
3010 spin_lock(&mm
->page_table_lock
);
3011 if (pgd_present(*pgd
)) /* Another has populated it */
3014 pgd_populate(mm
, pgd
, new);
3015 spin_unlock(&mm
->page_table_lock
);
3018 #endif /* __PAGETABLE_PUD_FOLDED */
3020 #ifndef __PAGETABLE_PMD_FOLDED
3022 * Allocate page middle directory.
3023 * We've already handled the fast-path in-line.
3025 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
3027 pmd_t
*new = pmd_alloc_one(mm
, address
);
3031 smp_wmb(); /* See comment in __pte_alloc */
3033 spin_lock(&mm
->page_table_lock
);
3034 #ifndef __ARCH_HAS_4LEVEL_HACK
3035 if (pud_present(*pud
)) /* Another has populated it */
3038 pud_populate(mm
, pud
, new);
3040 if (pgd_present(*pud
)) /* Another has populated it */
3043 pgd_populate(mm
, pud
, new);
3044 #endif /* __ARCH_HAS_4LEVEL_HACK */
3045 spin_unlock(&mm
->page_table_lock
);
3048 #endif /* __PAGETABLE_PMD_FOLDED */
3050 int make_pages_present(unsigned long addr
, unsigned long end
)
3052 int ret
, len
, write
;
3053 struct vm_area_struct
* vma
;
3055 vma
= find_vma(current
->mm
, addr
);
3058 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
3059 BUG_ON(addr
>= end
);
3060 BUG_ON(end
> vma
->vm_end
);
3061 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
3062 ret
= get_user_pages(current
, current
->mm
, addr
,
3063 len
, write
, 0, NULL
, NULL
);
3066 return ret
== len
? 0 : -EFAULT
;
3069 #if !defined(__HAVE_ARCH_GATE_AREA)
3071 #if defined(AT_SYSINFO_EHDR)
3072 static struct vm_area_struct gate_vma
;
3074 static int __init
gate_vma_init(void)
3076 gate_vma
.vm_mm
= NULL
;
3077 gate_vma
.vm_start
= FIXADDR_USER_START
;
3078 gate_vma
.vm_end
= FIXADDR_USER_END
;
3079 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
3080 gate_vma
.vm_page_prot
= __P101
;
3082 * Make sure the vDSO gets into every core dump.
3083 * Dumping its contents makes post-mortem fully interpretable later
3084 * without matching up the same kernel and hardware config to see
3085 * what PC values meant.
3087 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
3090 __initcall(gate_vma_init
);
3093 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
3095 #ifdef AT_SYSINFO_EHDR
3102 int in_gate_area_no_task(unsigned long addr
)
3104 #ifdef AT_SYSINFO_EHDR
3105 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
3111 #endif /* __HAVE_ARCH_GATE_AREA */
3113 static int follow_pte(struct mm_struct
*mm
, unsigned long address
,
3114 pte_t
**ptepp
, spinlock_t
**ptlp
)
3121 pgd
= pgd_offset(mm
, address
);
3122 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
3125 pud
= pud_offset(pgd
, address
);
3126 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
3129 pmd
= pmd_offset(pud
, address
);
3130 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
3133 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3137 ptep
= pte_offset_map_lock(mm
, pmd
, address
, ptlp
);
3140 if (!pte_present(*ptep
))
3145 pte_unmap_unlock(ptep
, *ptlp
);
3151 * follow_pfn - look up PFN at a user virtual address
3152 * @vma: memory mapping
3153 * @address: user virtual address
3154 * @pfn: location to store found PFN
3156 * Only IO mappings and raw PFN mappings are allowed.
3158 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3160 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
3167 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3170 ret
= follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
);
3173 *pfn
= pte_pfn(*ptep
);
3174 pte_unmap_unlock(ptep
, ptl
);
3177 EXPORT_SYMBOL(follow_pfn
);
3179 #ifdef CONFIG_HAVE_IOREMAP_PROT
3180 int follow_phys(struct vm_area_struct
*vma
,
3181 unsigned long address
, unsigned int flags
,
3182 unsigned long *prot
, resource_size_t
*phys
)
3188 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3191 if (follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
))
3195 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
3198 *prot
= pgprot_val(pte_pgprot(pte
));
3199 *phys
= (resource_size_t
)pte_pfn(pte
) << PAGE_SHIFT
;
3203 pte_unmap_unlock(ptep
, ptl
);
3208 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
3209 void *buf
, int len
, int write
)
3211 resource_size_t phys_addr
;
3212 unsigned long prot
= 0;
3213 void __iomem
*maddr
;
3214 int offset
= addr
& (PAGE_SIZE
-1);
3216 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
3219 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
3221 memcpy_toio(maddr
+ offset
, buf
, len
);
3223 memcpy_fromio(buf
, maddr
+ offset
, len
);
3231 * Access another process' address space.
3232 * Source/target buffer must be kernel space,
3233 * Do not walk the page table directly, use get_user_pages
3235 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
3237 struct mm_struct
*mm
;
3238 struct vm_area_struct
*vma
;
3239 void *old_buf
= buf
;
3241 mm
= get_task_mm(tsk
);
3245 down_read(&mm
->mmap_sem
);
3246 /* ignore errors, just check how much was successfully transferred */
3248 int bytes
, ret
, offset
;
3250 struct page
*page
= NULL
;
3252 ret
= get_user_pages(tsk
, mm
, addr
, 1,
3253 write
, 1, &page
, &vma
);
3256 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3257 * we can access using slightly different code.
3259 #ifdef CONFIG_HAVE_IOREMAP_PROT
3260 vma
= find_vma(mm
, addr
);
3263 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
3264 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
3272 offset
= addr
& (PAGE_SIZE
-1);
3273 if (bytes
> PAGE_SIZE
-offset
)
3274 bytes
= PAGE_SIZE
-offset
;
3278 copy_to_user_page(vma
, page
, addr
,
3279 maddr
+ offset
, buf
, bytes
);
3280 set_page_dirty_lock(page
);
3282 copy_from_user_page(vma
, page
, addr
,
3283 buf
, maddr
+ offset
, bytes
);
3286 page_cache_release(page
);
3292 up_read(&mm
->mmap_sem
);
3295 return buf
- old_buf
;
3299 * Print the name of a VMA.
3301 void print_vma_addr(char *prefix
, unsigned long ip
)
3303 struct mm_struct
*mm
= current
->mm
;
3304 struct vm_area_struct
*vma
;
3307 * Do not print if we are in atomic
3308 * contexts (in exception stacks, etc.):
3310 if (preempt_count())
3313 down_read(&mm
->mmap_sem
);
3314 vma
= find_vma(mm
, ip
);
3315 if (vma
&& vma
->vm_file
) {
3316 struct file
*f
= vma
->vm_file
;
3317 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
3321 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
3324 s
= strrchr(p
, '/');
3327 printk("%s%s[%lx+%lx]", prefix
, p
,
3329 vma
->vm_end
- vma
->vm_start
);
3330 free_page((unsigned long)buf
);
3333 up_read(¤t
->mm
->mmap_sem
);
3336 #ifdef CONFIG_PROVE_LOCKING
3337 void might_fault(void)
3340 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3341 * holding the mmap_sem, this is safe because kernel memory doesn't
3342 * get paged out, therefore we'll never actually fault, and the
3343 * below annotations will generate false positives.
3345 if (segment_eq(get_fs(), KERNEL_DS
))
3350 * it would be nicer only to annotate paths which are not under
3351 * pagefault_disable, however that requires a larger audit and
3352 * providing helpers like get_user_atomic.
3354 if (!in_atomic() && current
->mm
)
3355 might_lock_read(¤t
->mm
->mmap_sem
);
3357 EXPORT_SYMBOL(might_fault
);