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)
39 #include <linux/kernel_stat.h>
41 #include <linux/hugetlb.h>
42 #include <linux/mman.h>
43 #include <linux/swap.h>
44 #include <linux/highmem.h>
45 #include <linux/pagemap.h>
46 #include <linux/rmap.h>
47 #include <linux/module.h>
48 #include <linux/init.h>
50 #include <asm/pgalloc.h>
51 #include <asm/uaccess.h>
53 #include <asm/tlbflush.h>
54 #include <asm/pgtable.h>
56 #include <linux/swapops.h>
57 #include <linux/elf.h>
59 #ifndef CONFIG_DISCONTIGMEM
60 /* use the per-pgdat data instead for discontigmem - mbligh */
61 unsigned long max_mapnr;
64 EXPORT_SYMBOL(max_mapnr);
65 EXPORT_SYMBOL(mem_map);
68 unsigned long num_physpages;
70 * A number of key systems in x86 including ioremap() rely on the assumption
71 * that high_memory defines the upper bound on direct map memory, then end
72 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
73 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
77 struct page *highmem_start_page;
78 unsigned long vmalloc_earlyreserve;
80 EXPORT_SYMBOL(num_physpages);
81 EXPORT_SYMBOL(highmem_start_page);
82 EXPORT_SYMBOL(high_memory);
83 EXPORT_SYMBOL(vmalloc_earlyreserve);
86 * We special-case the C-O-W ZERO_PAGE, because it's such
87 * a common occurrence (no need to read the page to know
88 * that it's zero - better for the cache and memory subsystem).
90 static inline void copy_cow_page(struct page * from, struct page * to, unsigned long address)
92 if (from == ZERO_PAGE(address)) {
93 clear_user_highpage(to, address);
96 copy_user_highpage(to, from, address);
100 * Note: this doesn't free the actual pages themselves. That
101 * has been handled earlier when unmapping all the memory regions.
103 static inline void free_one_pmd(struct mmu_gather *tlb, pmd_t * dir)
109 if (unlikely(pmd_bad(*dir))) {
114 page = pmd_page(*dir);
116 dec_page_state(nr_page_table_pages);
117 pte_free_tlb(tlb, page);
120 static inline void free_one_pgd(struct mmu_gather *tlb, pgd_t * dir)
127 if (unlikely(pgd_bad(*dir))) {
132 pmd = pmd_offset(dir, 0);
134 for (j = 0; j < PTRS_PER_PMD ; j++)
135 free_one_pmd(tlb, pmd+j);
136 pmd_free_tlb(tlb, pmd);
140 * This function clears all user-level page tables of a process - this
141 * is needed by execve(), so that old pages aren't in the way.
143 * Must be called with pagetable lock held.
145 void clear_page_tables(struct mmu_gather *tlb, unsigned long first, int nr)
147 pgd_t * page_dir = tlb->mm->pgd;
151 free_one_pgd(tlb, page_dir);
156 pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
158 if (!pmd_present(*pmd)) {
161 spin_unlock(&mm->page_table_lock);
162 new = pte_alloc_one(mm, address);
163 spin_lock(&mm->page_table_lock);
168 * Because we dropped the lock, we should re-check the
169 * entry, as somebody else could have populated it..
171 if (pmd_present(*pmd)) {
175 inc_page_state(nr_page_table_pages);
176 pmd_populate(mm, pmd, new);
179 return pte_offset_map(pmd, address);
182 pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
184 if (!pmd_present(*pmd)) {
187 spin_unlock(&mm->page_table_lock);
188 new = pte_alloc_one_kernel(mm, address);
189 spin_lock(&mm->page_table_lock);
194 * Because we dropped the lock, we should re-check the
195 * entry, as somebody else could have populated it..
197 if (pmd_present(*pmd)) {
198 pte_free_kernel(new);
201 pmd_populate_kernel(mm, pmd, new);
204 return pte_offset_kernel(pmd, address);
206 #define PTE_TABLE_MASK ((PTRS_PER_PTE-1) * sizeof(pte_t))
207 #define PMD_TABLE_MASK ((PTRS_PER_PMD-1) * sizeof(pmd_t))
210 * copy one vm_area from one task to the other. Assumes the page tables
211 * already present in the new task to be cleared in the whole range
212 * covered by this vma.
214 * 08Jan98 Merged into one routine from several inline routines to reduce
215 * variable count and make things faster. -jj
217 * dst->page_table_lock is held on entry and exit,
218 * but may be dropped within pmd_alloc() and pte_alloc_map().
220 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
221 struct vm_area_struct *vma)
223 pgd_t * src_pgd, * dst_pgd;
224 unsigned long address = vma->vm_start;
225 unsigned long end = vma->vm_end;
228 if (is_vm_hugetlb_page(vma))
229 return copy_hugetlb_page_range(dst, src, vma);
231 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
232 src_pgd = pgd_offset(src, address)-1;
233 dst_pgd = pgd_offset(dst, address)-1;
236 pmd_t * src_pmd, * dst_pmd;
238 src_pgd++; dst_pgd++;
242 if (pgd_none(*src_pgd))
243 goto skip_copy_pmd_range;
244 if (unlikely(pgd_bad(*src_pgd))) {
247 skip_copy_pmd_range: address = (address + PGDIR_SIZE) & PGDIR_MASK;
248 if (!address || (address >= end))
253 src_pmd = pmd_offset(src_pgd, address);
254 dst_pmd = pmd_alloc(dst, dst_pgd, address);
259 pte_t * src_pte, * dst_pte;
263 if (pmd_none(*src_pmd))
264 goto skip_copy_pte_range;
265 if (unlikely(pmd_bad(*src_pmd))) {
269 address = (address + PMD_SIZE) & PMD_MASK;
272 goto cont_copy_pmd_range;
275 dst_pte = pte_alloc_map(dst, dst_pmd, address);
278 spin_lock(&src->page_table_lock);
279 src_pte = pte_offset_map_nested(src_pmd, address);
281 pte_t pte = *src_pte;
285 if (!vx_rsspages_avail(dst, 1)) {
286 spin_unlock(&src->page_table_lock);
292 goto cont_copy_pte_range_noset;
293 /* pte contains position in swap, so copy. */
294 if (!pte_present(pte)) {
296 swap_duplicate(pte_to_swp_entry(pte));
297 set_pte(dst_pte, pte);
298 goto cont_copy_pte_range_noset;
301 /* the pte points outside of valid memory, the
302 * mapping is assumed to be good, meaningful
303 * and not mapped via rmap - duplicate the
308 page = pfn_to_page(pfn);
310 if (!page || PageReserved(page)) {
311 set_pte(dst_pte, pte);
312 goto cont_copy_pte_range_noset;
316 * If it's a COW mapping, write protect it both
317 * in the parent and the child
320 ptep_set_wrprotect(src_pte);
325 * If it's a shared mapping, mark it clean in
328 if (vma->vm_flags & VM_SHARED)
329 pte = pte_mkclean(pte);
330 pte = pte_mkold(pte);
333 vx_rsspages_inc(dst);
336 set_pte(dst_pte, pte);
338 cont_copy_pte_range_noset:
339 address += PAGE_SIZE;
340 if (address >= end) {
341 pte_unmap_nested(src_pte);
347 } while ((unsigned long)src_pte & PTE_TABLE_MASK);
348 pte_unmap_nested(src_pte-1);
349 pte_unmap(dst_pte-1);
350 spin_unlock(&src->page_table_lock);
351 cond_resched_lock(&dst->page_table_lock);
355 } while ((unsigned long)src_pmd & PMD_TABLE_MASK);
358 spin_unlock(&src->page_table_lock);
365 static void zap_pte_range(struct mmu_gather *tlb,
366 pmd_t *pmd, unsigned long address,
367 unsigned long size, struct zap_details *details)
369 unsigned long offset;
374 if (unlikely(pmd_bad(*pmd))) {
379 ptep = pte_offset_map(pmd, address);
380 offset = address & ~PMD_MASK;
381 if (offset + size > PMD_SIZE)
382 size = PMD_SIZE - offset;
384 if (details && !details->check_mapping && !details->nonlinear_vma)
386 for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) {
390 if (pte_present(pte)) {
391 struct page *page = NULL;
392 unsigned long pfn = pte_pfn(pte);
393 if (pfn_valid(pfn)) {
394 page = pfn_to_page(pfn);
395 if (PageReserved(page))
398 if (unlikely(details) && page) {
400 * unmap_shared_mapping_pages() wants to
401 * invalidate cache without truncating:
402 * unmap shared but keep private pages.
404 if (details->check_mapping &&
405 details->check_mapping != page->mapping)
408 * Each page->index must be checked when
409 * invalidating or truncating nonlinear.
411 if (details->nonlinear_vma &&
412 (page->index < details->first_index ||
413 page->index > details->last_index))
416 pte = ptep_get_and_clear(ptep);
417 tlb_remove_tlb_entry(tlb, ptep, address+offset);
420 if (unlikely(details) && details->nonlinear_vma
421 && linear_page_index(details->nonlinear_vma,
422 address+offset) != page->index)
423 set_pte(ptep, pgoff_to_pte(page->index));
425 set_page_dirty(page);
428 else if (pte_young(pte))
429 mark_page_accessed(page);
431 page_remove_rmap(page);
432 tlb_remove_page(tlb, page);
436 * If details->check_mapping, we leave swap entries;
437 * if details->nonlinear_vma, we leave file entries.
439 if (unlikely(details))
442 free_swap_and_cache(pte_to_swp_entry(pte));
448 static void zap_pmd_range(struct mmu_gather *tlb,
449 pgd_t * dir, unsigned long address,
450 unsigned long size, struct zap_details *details)
457 if (unlikely(pgd_bad(*dir))) {
462 pmd = pmd_offset(dir, address);
463 end = address + size;
464 if (end > ((address + PGDIR_SIZE) & PGDIR_MASK))
465 end = ((address + PGDIR_SIZE) & PGDIR_MASK);
467 zap_pte_range(tlb, pmd, address, end - address, details);
468 address = (address + PMD_SIZE) & PMD_MASK;
470 } while (address && (address < end));
473 static void unmap_page_range(struct mmu_gather *tlb,
474 struct vm_area_struct *vma, unsigned long address,
475 unsigned long end, struct zap_details *details)
479 BUG_ON(address >= end);
480 dir = pgd_offset(vma->vm_mm, address);
481 tlb_start_vma(tlb, vma);
483 zap_pmd_range(tlb, dir, address, end - address, details);
484 address = (address + PGDIR_SIZE) & PGDIR_MASK;
486 } while (address && (address < end));
487 tlb_end_vma(tlb, vma);
490 #ifdef CONFIG_PREEMPT_VOLUNTARY
491 # define ZAP_BLOCK_SIZE (128 * PAGE_SIZE)
494 /* Dispose of an entire struct mmu_gather per rescheduling point */
495 #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
496 #define ZAP_BLOCK_SIZE (FREE_PTE_NR * PAGE_SIZE)
499 /* For UP, 256 pages at a time gives nice low latency */
500 #if !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
501 #define ZAP_BLOCK_SIZE (256 * PAGE_SIZE)
504 /* No preempt: go for improved straight-line efficiency */
505 #if !defined(CONFIG_PREEMPT)
506 #define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
512 * unmap_vmas - unmap a range of memory covered by a list of vma's
513 * @tlbp: address of the caller's struct mmu_gather
514 * @mm: the controlling mm_struct
515 * @vma: the starting vma
516 * @start_addr: virtual address at which to start unmapping
517 * @end_addr: virtual address at which to end unmapping
518 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
519 * @details: details of nonlinear truncation or shared cache invalidation
521 * Returns the number of vma's which were covered by the unmapping.
523 * Unmap all pages in the vma list. Called under page_table_lock.
525 * We aim to not hold page_table_lock for too long (for scheduling latency
526 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
527 * return the ending mmu_gather to the caller.
529 * Only addresses between `start' and `end' will be unmapped.
531 * The VMA list must be sorted in ascending virtual address order.
533 * unmap_vmas() assumes that the caller will flush the whole unmapped address
534 * range after unmap_vmas() returns. So the only responsibility here is to
535 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
536 * drops the lock and schedules.
538 int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
539 struct vm_area_struct *vma, unsigned long start_addr,
540 unsigned long end_addr, unsigned long *nr_accounted,
541 struct zap_details *details)
543 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
544 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
545 int tlb_start_valid = 0;
547 int atomic = details && details->atomic;
549 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
553 start = max(vma->vm_start, start_addr);
554 if (start >= vma->vm_end)
556 end = min(vma->vm_end, end_addr);
557 if (end <= vma->vm_start)
560 if (vma->vm_flags & VM_ACCOUNT)
561 *nr_accounted += (end - start) >> PAGE_SHIFT;
564 while (start != end) {
567 if (!tlb_start_valid) {
572 if (is_vm_hugetlb_page(vma)) {
574 unmap_hugepage_range(vma, start, end);
576 block = min(zap_bytes, end - start);
577 unmap_page_range(*tlbp, vma, start,
578 start + block, details);
583 if (!atomic && need_resched()) {
584 int fullmm = tlb_is_full_mm(*tlbp);
585 tlb_finish_mmu(*tlbp, tlb_start, start);
586 cond_resched_lock(&mm->page_table_lock);
587 *tlbp = tlb_gather_mmu(mm, fullmm);
590 if ((long)zap_bytes > 0)
592 zap_bytes = ZAP_BLOCK_SIZE;
599 * zap_page_range - remove user pages in a given range
600 * @vma: vm_area_struct holding the applicable pages
601 * @address: starting address of pages to zap
602 * @size: number of bytes to zap
603 * @details: details of nonlinear truncation or shared cache invalidation
605 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
606 unsigned long size, struct zap_details *details)
608 struct mm_struct *mm = vma->vm_mm;
609 struct mmu_gather *tlb;
610 unsigned long end = address + size;
611 unsigned long nr_accounted = 0;
613 if (is_vm_hugetlb_page(vma)) {
614 zap_hugepage_range(vma, address, size);
619 spin_lock(&mm->page_table_lock);
620 tlb = tlb_gather_mmu(mm, 0);
621 unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
622 tlb_finish_mmu(tlb, address, end);
623 spin_unlock(&mm->page_table_lock);
627 * Do a quick page-table lookup for a single page.
628 * mm->page_table_lock must be held.
631 follow_page(struct mm_struct *mm, unsigned long address, int write)
639 page = follow_huge_addr(mm, address, write);
643 pgd = pgd_offset(mm, address);
644 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
647 pmd = pmd_offset(pgd, address);
651 return follow_huge_pmd(mm, address, pmd, write);
652 if (unlikely(pmd_bad(*pmd)))
655 ptep = pte_offset_map(pmd, address);
661 if (pte_present(pte)) {
662 if (write && !pte_write(pte))
665 if (pfn_valid(pfn)) {
666 page = pfn_to_page(pfn);
667 if (write && !pte_dirty(pte) && !PageDirty(page))
668 set_page_dirty(page);
669 mark_page_accessed(page);
679 * Given a physical address, is there a useful struct page pointing to
680 * it? This may become more complex in the future if we start dealing
681 * with IO-aperture pages for direct-IO.
684 static inline struct page *get_page_map(struct page *page)
686 if (!pfn_valid(page_to_pfn(page)))
693 untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
694 unsigned long address)
699 /* Check if the vma is for an anonymous mapping. */
700 if (vma->vm_ops && vma->vm_ops->nopage)
703 /* Check if page directory entry exists. */
704 pgd = pgd_offset(mm, address);
705 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
708 /* Check if page middle directory entry exists. */
709 pmd = pmd_offset(pgd, address);
710 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
713 /* There is a pte slot for 'address' in 'mm'. */
718 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
719 unsigned long start, int len, int write, int force,
720 struct page **pages, struct vm_area_struct **vmas)
726 * Require read or write permissions.
727 * If 'force' is set, we only require the "MAY" flags.
729 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
730 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
734 struct vm_area_struct * vma;
736 vma = find_extend_vma(mm, start);
737 if (!vma && in_gate_area(tsk, start)) {
738 unsigned long pg = start & PAGE_MASK;
739 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
743 if (write) /* user gate pages are read-only */
744 return i ? : -EFAULT;
746 pgd = pgd_offset_k(pg);
748 pgd = pgd_offset_gate(mm, pg);
749 BUG_ON(pgd_none(*pgd));
750 pmd = pmd_offset(pgd, pg);
751 BUG_ON(pmd_none(*pmd));
752 pte = pte_offset_map(pmd, pg);
753 BUG_ON(pte_none(*pte));
755 pages[i] = pte_page(*pte);
767 if (!vma || (vma->vm_flags & VM_IO)
768 || !(flags & vma->vm_flags))
769 return i ? : -EFAULT;
771 if (is_vm_hugetlb_page(vma)) {
772 i = follow_hugetlb_page(mm, vma, pages, vmas,
776 spin_lock(&mm->page_table_lock);
779 int lookup_write = write;
780 while (!(map = follow_page(mm, start, lookup_write))) {
782 * Shortcut for anonymous pages. We don't want
783 * to force the creation of pages tables for
784 * insanly big anonymously mapped areas that
785 * nobody touched so far. This is important
786 * for doing a core dump for these mappings.
789 untouched_anonymous_page(mm,vma,start)) {
790 map = ZERO_PAGE(start);
793 spin_unlock(&mm->page_table_lock);
794 switch (handle_mm_fault(mm,vma,start,write)) {
801 case VM_FAULT_SIGBUS:
802 return i ? i : -EFAULT;
804 return i ? i : -ENOMEM;
809 * Now that we have performed a write fault
810 * and surely no longer have a shared page we
811 * shouldn't write, we shouldn't ignore an
812 * unwritable page in the page table if
813 * we are forcing write access.
815 lookup_write = write && !force;
816 spin_lock(&mm->page_table_lock);
819 pages[i] = get_page_map(map);
821 spin_unlock(&mm->page_table_lock);
823 page_cache_release(pages[i]);
827 flush_dcache_page(pages[i]);
828 if (!PageReserved(pages[i]))
829 page_cache_get(pages[i]);
836 } while(len && start < vma->vm_end);
837 spin_unlock(&mm->page_table_lock);
843 EXPORT_SYMBOL(get_user_pages);
845 static void zeromap_pte_range(pte_t * pte, unsigned long address,
846 unsigned long size, pgprot_t prot)
850 address &= ~PMD_MASK;
851 end = address + size;
855 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot));
856 BUG_ON(!pte_none(*pte));
857 set_pte(pte, zero_pte);
858 address += PAGE_SIZE;
860 } while (address && (address < end));
863 static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address,
864 unsigned long size, pgprot_t prot)
866 unsigned long base, end;
868 base = address & PGDIR_MASK;
869 address &= ~PGDIR_MASK;
870 end = address + size;
871 if (end > PGDIR_SIZE)
874 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
877 zeromap_pte_range(pte, base + address, end - address, prot);
879 address = (address + PMD_SIZE) & PMD_MASK;
881 } while (address && (address < end));
885 int zeromap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, pgprot_t prot)
889 unsigned long beg = address;
890 unsigned long end = address + size;
891 struct mm_struct *mm = vma->vm_mm;
893 dir = pgd_offset(mm, address);
894 flush_cache_range(vma, beg, end);
898 spin_lock(&mm->page_table_lock);
900 pmd_t *pmd = pmd_alloc(mm, dir, address);
904 error = zeromap_pmd_range(mm, pmd, address, end - address, prot);
907 address = (address + PGDIR_SIZE) & PGDIR_MASK;
909 } while (address && (address < end));
911 * Why flush? zeromap_pte_range has a BUG_ON for !pte_none()
913 flush_tlb_range(vma, beg, end);
914 spin_unlock(&mm->page_table_lock);
919 * maps a range of physical memory into the requested pages. the old
920 * mappings are removed. any references to nonexistent pages results
921 * in null mappings (currently treated as "copy-on-access")
923 static inline void remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
924 unsigned long phys_addr, pgprot_t prot)
929 address &= ~PMD_MASK;
930 end = address + size;
933 pfn = phys_addr >> PAGE_SHIFT;
935 BUG_ON(!pte_none(*pte));
936 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
937 set_pte(pte, pfn_pte(pfn, prot));
938 address += PAGE_SIZE;
941 } while (address && (address < end));
944 static inline int remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
945 unsigned long phys_addr, pgprot_t prot)
947 unsigned long base, end;
949 base = address & PGDIR_MASK;
950 address &= ~PGDIR_MASK;
951 end = address + size;
952 if (end > PGDIR_SIZE)
954 phys_addr -= address;
956 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
959 remap_pte_range(pte, base + address, end - address, address + phys_addr, prot);
961 address = (address + PMD_SIZE) & PMD_MASK;
963 } while (address && (address < end));
967 /* Note: this is only safe if the mm semaphore is held when called. */
968 int remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long phys_addr, unsigned long size, pgprot_t prot)
972 unsigned long beg = from;
973 unsigned long end = from + size;
974 struct mm_struct *mm = vma->vm_mm;
977 dir = pgd_offset(mm, from);
978 flush_cache_range(vma, beg, end);
983 * Physically remapped pages are special. Tell the
984 * rest of the world about it:
985 * VM_IO tells people not to look at these pages
986 * (accesses can have side effects).
987 * VM_RESERVED tells swapout not to try to touch
990 vma->vm_flags |= VM_IO | VM_RESERVED;
992 spin_lock(&mm->page_table_lock);
994 pmd_t *pmd = pmd_alloc(mm, dir, from);
998 error = remap_pmd_range(mm, pmd, from, end - from, phys_addr + from, prot);
1001 from = (from + PGDIR_SIZE) & PGDIR_MASK;
1003 } while (from && (from < end));
1005 * Why flush? remap_pte_range has a BUG_ON for !pte_none()
1007 flush_tlb_range(vma, beg, end);
1008 spin_unlock(&mm->page_table_lock);
1012 EXPORT_SYMBOL(remap_page_range);
1015 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1016 * servicing faults for write access. In the normal case, do always want
1017 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1018 * that do not have writing enabled, when used by access_process_vm.
1020 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1022 if (likely(vma->vm_flags & VM_WRITE))
1023 pte = pte_mkwrite(pte);
1028 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1030 static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
1035 flush_cache_page(vma, address);
1036 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
1038 ptep_establish(vma, address, page_table, entry);
1039 update_mmu_cache(vma, address, entry);
1043 * This routine handles present pages, when users try to write
1044 * to a shared page. It is done by copying the page to a new address
1045 * and decrementing the shared-page counter for the old page.
1047 * Goto-purists beware: the only reason for goto's here is that it results
1048 * in better assembly code.. The "default" path will see no jumps at all.
1050 * Note that this routine assumes that the protection checks have been
1051 * done by the caller (the low-level page fault routine in most cases).
1052 * Thus we can safely just mark it writable once we've done any necessary
1055 * We also mark the page dirty at this point even though the page will
1056 * change only once the write actually happens. This avoids a few races,
1057 * and potentially makes it more efficient.
1059 * We hold the mm semaphore and the page_table_lock on entry and exit
1060 * with the page_table_lock released.
1062 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
1063 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
1065 struct page *old_page, *new_page;
1066 unsigned long pfn = pte_pfn(pte);
1069 if (unlikely(!pfn_valid(pfn))) {
1071 * This should really halt the system so it can be debugged or
1072 * at least the kernel stops what it's doing before it corrupts
1073 * data, but for the moment just pretend this is OOM.
1075 pte_unmap(page_table);
1076 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
1078 spin_unlock(&mm->page_table_lock);
1079 return VM_FAULT_OOM;
1081 old_page = pfn_to_page(pfn);
1083 if (!TestSetPageLocked(old_page)) {
1084 int reuse = can_share_swap_page(old_page);
1085 unlock_page(old_page);
1087 flush_cache_page(vma, address);
1088 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
1090 ptep_set_access_flags(vma, address, page_table, entry, 1);
1091 update_mmu_cache(vma, address, entry);
1092 pte_unmap(page_table);
1093 spin_unlock(&mm->page_table_lock);
1094 return VM_FAULT_MINOR;
1097 pte_unmap(page_table);
1100 * Ok, we need to copy. Oh, well..
1102 if (!PageReserved(old_page))
1103 page_cache_get(old_page);
1104 spin_unlock(&mm->page_table_lock);
1106 if (unlikely(anon_vma_prepare(vma)))
1108 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1111 copy_cow_page(old_page,new_page,address);
1114 * Re-check the pte - we dropped the lock
1116 spin_lock(&mm->page_table_lock);
1117 page_table = pte_offset_map(pmd, address);
1118 if (likely(pte_same(*page_table, pte))) {
1119 if (PageAnon(old_page))
1121 if (PageReserved(old_page))
1123 vx_rsspages_inc(mm);
1125 page_remove_rmap(old_page);
1126 break_cow(vma, new_page, address, page_table);
1127 lru_cache_add_active(new_page);
1128 page_add_anon_rmap(new_page, vma, address);
1130 /* Free the old page.. */
1131 new_page = old_page;
1133 pte_unmap(page_table);
1134 page_cache_release(new_page);
1135 page_cache_release(old_page);
1136 spin_unlock(&mm->page_table_lock);
1137 return VM_FAULT_MINOR;
1140 page_cache_release(old_page);
1141 return VM_FAULT_OOM;
1145 * Helper function for unmap_mapping_range().
1147 static inline void unmap_mapping_range_list(struct prio_tree_root *root,
1148 struct zap_details *details)
1150 struct vm_area_struct *vma;
1151 struct prio_tree_iter iter;
1152 pgoff_t vba, vea, zba, zea;
1154 vma_prio_tree_foreach(vma, &iter, root,
1155 details->first_index, details->last_index) {
1156 vba = vma->vm_pgoff;
1157 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1158 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1159 zba = details->first_index;
1162 zea = details->last_index;
1166 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1167 (zea - zba + 1) << PAGE_SHIFT, details);
1172 * unmap_mapping_range - unmap the portion of all mmaps
1173 * in the specified address_space corresponding to the specified
1174 * page range in the underlying file.
1175 * @address_space: the address space containing mmaps to be unmapped.
1176 * @holebegin: byte in first page to unmap, relative to the start of
1177 * the underlying file. This will be rounded down to a PAGE_SIZE
1178 * boundary. Note that this is different from vmtruncate(), which
1179 * must keep the partial page. In contrast, we must get rid of
1181 * @holelen: size of prospective hole in bytes. This will be rounded
1182 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1184 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1185 * but 0 when invalidating pagecache, don't throw away private data.
1187 void unmap_mapping_range(struct address_space *mapping,
1188 loff_t const holebegin, loff_t const holelen, int even_cows)
1190 struct zap_details details;
1191 pgoff_t hba = holebegin >> PAGE_SHIFT;
1192 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1194 /* Check for overflow. */
1195 if (sizeof(holelen) > sizeof(hlen)) {
1197 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1198 if (holeend & ~(long long)ULONG_MAX)
1199 hlen = ULONG_MAX - hba + 1;
1202 details.check_mapping = even_cows? NULL: mapping;
1203 details.nonlinear_vma = NULL;
1204 details.first_index = hba;
1205 details.last_index = hba + hlen - 1;
1206 details.atomic = 1; /* A spinlock is held */
1207 if (details.last_index < details.first_index)
1208 details.last_index = ULONG_MAX;
1210 spin_lock(&mapping->i_mmap_lock);
1211 /* Protect against page fault */
1212 atomic_inc(&mapping->truncate_count);
1214 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1215 unmap_mapping_range_list(&mapping->i_mmap, &details);
1218 * In nonlinear VMAs there is no correspondence between virtual address
1219 * offset and file offset. So we must perform an exhaustive search
1220 * across *all* the pages in each nonlinear VMA, not just the pages
1221 * whose virtual address lies outside the file truncation point.
1223 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) {
1224 struct vm_area_struct *vma;
1225 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
1226 shared.vm_set.list) {
1227 details.nonlinear_vma = vma;
1228 zap_page_range(vma, vma->vm_start,
1229 vma->vm_end - vma->vm_start, &details);
1232 spin_unlock(&mapping->i_mmap_lock);
1234 EXPORT_SYMBOL(unmap_mapping_range);
1237 * Handle all mappings that got truncated by a "truncate()"
1240 * NOTE! We have to be ready to update the memory sharing
1241 * between the file and the memory map for a potential last
1242 * incomplete page. Ugly, but necessary.
1244 int vmtruncate(struct inode * inode, loff_t offset)
1246 struct address_space *mapping = inode->i_mapping;
1247 unsigned long limit;
1249 if (inode->i_size < offset)
1252 * truncation of in-use swapfiles is disallowed - it would cause
1253 * subsequent swapout to scribble on the now-freed blocks.
1255 if (IS_SWAPFILE(inode))
1257 i_size_write(inode, offset);
1258 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1259 truncate_inode_pages(mapping, offset);
1263 limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
1264 if (limit != RLIM_INFINITY && offset > limit)
1266 if (offset > inode->i_sb->s_maxbytes)
1268 i_size_write(inode, offset);
1271 if (inode->i_op && inode->i_op->truncate)
1272 inode->i_op->truncate(inode);
1275 send_sig(SIGXFSZ, current, 0);
1282 EXPORT_SYMBOL(vmtruncate);
1285 * Primitive swap readahead code. We simply read an aligned block of
1286 * (1 << page_cluster) entries in the swap area. This method is chosen
1287 * because it doesn't cost us any seek time. We also make sure to queue
1288 * the 'original' request together with the readahead ones...
1290 * This has been extended to use the NUMA policies from the mm triggering
1293 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1295 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1298 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1301 struct page *new_page;
1302 unsigned long offset;
1305 * Get the number of handles we should do readahead io to.
1307 num = valid_swaphandles(entry, &offset);
1308 for (i = 0; i < num; offset++, i++) {
1309 /* Ok, do the async read-ahead now */
1310 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1311 offset), vma, addr);
1314 page_cache_release(new_page);
1317 * Find the next applicable VMA for the NUMA policy.
1323 if (addr >= vma->vm_end) {
1325 next_vma = vma ? vma->vm_next : NULL;
1327 if (vma && addr < vma->vm_start)
1330 if (next_vma && addr >= next_vma->vm_start) {
1332 next_vma = vma->vm_next;
1337 lru_add_drain(); /* Push any new pages onto the LRU now */
1341 * We hold the mm semaphore and the page_table_lock on entry and
1342 * should release the pagetable lock on exit..
1344 static int do_swap_page(struct mm_struct * mm,
1345 struct vm_area_struct * vma, unsigned long address,
1346 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
1349 swp_entry_t entry = pte_to_swp_entry(orig_pte);
1351 int ret = VM_FAULT_MINOR;
1353 pte_unmap(page_table);
1354 spin_unlock(&mm->page_table_lock);
1355 page = lookup_swap_cache(entry);
1357 swapin_readahead(entry, address, vma);
1358 page = read_swap_cache_async(entry, vma, address);
1361 * Back out if somebody else faulted in this pte while
1362 * we released the page table lock.
1364 spin_lock(&mm->page_table_lock);
1365 page_table = pte_offset_map(pmd, address);
1366 if (likely(pte_same(*page_table, orig_pte)))
1369 ret = VM_FAULT_MINOR;
1370 pte_unmap(page_table);
1371 spin_unlock(&mm->page_table_lock);
1375 /* Had to read the page from swap area: Major fault */
1376 ret = VM_FAULT_MAJOR;
1377 inc_page_state(pgmajfault);
1381 if (!vx_rsspages_avail(mm, 1)) {
1385 mark_page_accessed(page);
1389 * Back out if somebody else faulted in this pte while we
1390 * released the page table lock.
1392 spin_lock(&mm->page_table_lock);
1393 page_table = pte_offset_map(pmd, address);
1394 if (unlikely(!pte_same(*page_table, orig_pte))) {
1395 pte_unmap(page_table);
1396 spin_unlock(&mm->page_table_lock);
1398 page_cache_release(page);
1399 ret = VM_FAULT_MINOR;
1403 /* The page isn't present yet, go ahead with the fault. */
1407 remove_exclusive_swap_page(page);
1410 vx_rsspages_inc(mm);
1411 pte = mk_pte(page, vma->vm_page_prot);
1412 if (write_access && can_share_swap_page(page)) {
1413 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1418 flush_icache_page(vma, page);
1419 set_pte(page_table, pte);
1420 page_add_anon_rmap(page, vma, address);
1423 if (do_wp_page(mm, vma, address,
1424 page_table, pmd, pte) == VM_FAULT_OOM)
1429 /* No need to invalidate - it was non-present before */
1430 update_mmu_cache(vma, address, pte);
1431 pte_unmap(page_table);
1432 spin_unlock(&mm->page_table_lock);
1438 * We are called with the MM semaphore and page_table_lock
1439 * spinlock held to protect against concurrent faults in
1440 * multithreaded programs.
1443 do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1444 pte_t *page_table, pmd_t *pmd, int write_access,
1448 struct page * page = ZERO_PAGE(addr);
1450 /* Read-only mapping of ZERO_PAGE. */
1451 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
1453 /* ..except if it's a write access */
1455 /* Allocate our own private page. */
1456 pte_unmap(page_table);
1457 spin_unlock(&mm->page_table_lock);
1459 if (unlikely(anon_vma_prepare(vma)))
1461 if (!vx_rsspages_avail(mm, 1))
1464 page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
1467 clear_user_highpage(page, addr);
1469 spin_lock(&mm->page_table_lock);
1470 page_table = pte_offset_map(pmd, addr);
1472 if (!pte_none(*page_table)) {
1473 pte_unmap(page_table);
1474 page_cache_release(page);
1475 spin_unlock(&mm->page_table_lock);
1479 vx_rsspages_inc(mm);
1480 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
1481 vma->vm_page_prot)),
1483 lru_cache_add_active(page);
1484 mark_page_accessed(page);
1485 page_add_anon_rmap(page, vma, addr);
1488 set_pte(page_table, entry);
1489 pte_unmap(page_table);
1491 /* No need to invalidate - it was non-present before */
1492 update_mmu_cache(vma, addr, entry);
1493 spin_unlock(&mm->page_table_lock);
1495 return VM_FAULT_MINOR;
1497 return VM_FAULT_OOM;
1501 * do_no_page() tries to create a new page mapping. It aggressively
1502 * tries to share with existing pages, but makes a separate copy if
1503 * the "write_access" parameter is true in order to avoid the next
1506 * As this is called only for pages that do not currently exist, we
1507 * do not need to flush old virtual caches or the TLB.
1509 * This is called with the MM semaphore held and the page table
1510 * spinlock held. Exit with the spinlock released.
1513 do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1514 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
1516 struct page * new_page;
1517 struct address_space *mapping = NULL;
1520 int ret = VM_FAULT_MINOR;
1523 if (!vma->vm_ops || !vma->vm_ops->nopage)
1524 return do_anonymous_page(mm, vma, page_table,
1525 pmd, write_access, address);
1526 pte_unmap(page_table);
1527 spin_unlock(&mm->page_table_lock);
1530 mapping = vma->vm_file->f_mapping;
1531 sequence = atomic_read(&mapping->truncate_count);
1533 smp_rmb(); /* Prevent CPU from reordering lock-free ->nopage() */
1535 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1537 /* no page was available -- either SIGBUS or OOM */
1538 if (new_page == NOPAGE_SIGBUS)
1539 return VM_FAULT_SIGBUS;
1540 if (new_page == NOPAGE_OOM)
1541 return VM_FAULT_OOM;
1542 if (!vx_rsspages_avail(mm, 1))
1543 return VM_FAULT_OOM;
1546 * Should we do an early C-O-W break?
1548 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1551 if (unlikely(anon_vma_prepare(vma)))
1553 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1556 copy_user_highpage(page, new_page, address);
1557 page_cache_release(new_page);
1562 spin_lock(&mm->page_table_lock);
1564 * For a file-backed vma, someone could have truncated or otherwise
1565 * invalidated this page. If unmap_mapping_range got called,
1566 * retry getting the page.
1569 (unlikely(sequence != atomic_read(&mapping->truncate_count)))) {
1570 sequence = atomic_read(&mapping->truncate_count);
1571 spin_unlock(&mm->page_table_lock);
1572 page_cache_release(new_page);
1575 page_table = pte_offset_map(pmd, address);
1578 * This silly early PAGE_DIRTY setting removes a race
1579 * due to the bad i386 page protection. But it's valid
1580 * for other architectures too.
1582 * Note that if write_access is true, we either now have
1583 * an exclusive copy of the page, or this is a shared mapping,
1584 * so we can make it writable and dirty to avoid having to
1585 * handle that later.
1587 /* Only go through if we didn't race with anybody else... */
1588 if (pte_none(*page_table)) {
1589 if (!PageReserved(new_page))
1591 vx_rsspages_inc(mm);
1592 flush_icache_page(vma, new_page);
1593 entry = mk_pte(new_page, vma->vm_page_prot);
1595 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1596 set_pte(page_table, entry);
1598 lru_cache_add_active(new_page);
1599 page_add_anon_rmap(new_page, vma, address);
1601 page_add_file_rmap(new_page);
1602 pte_unmap(page_table);
1604 /* One of our sibling threads was faster, back out. */
1605 pte_unmap(page_table);
1606 page_cache_release(new_page);
1607 spin_unlock(&mm->page_table_lock);
1611 /* no need to invalidate: a not-present page shouldn't be cached */
1612 update_mmu_cache(vma, address, entry);
1613 spin_unlock(&mm->page_table_lock);
1617 page_cache_release(new_page);
1623 * Fault of a previously existing named mapping. Repopulate the pte
1624 * from the encoded file_pte if possible. This enables swappable
1627 static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
1628 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
1630 unsigned long pgoff;
1633 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
1635 * Fall back to the linear mapping if the fs does not support
1638 if (!vma->vm_ops || !vma->vm_ops->populate ||
1639 (write_access && !(vma->vm_flags & VM_SHARED))) {
1641 return do_no_page(mm, vma, address, write_access, pte, pmd);
1644 pgoff = pte_to_pgoff(*pte);
1647 spin_unlock(&mm->page_table_lock);
1649 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
1651 return VM_FAULT_OOM;
1653 return VM_FAULT_SIGBUS;
1654 return VM_FAULT_MAJOR;
1658 * These routines also need to handle stuff like marking pages dirty
1659 * and/or accessed for architectures that don't do it in hardware (most
1660 * RISC architectures). The early dirtying is also good on the i386.
1662 * There is also a hook called "update_mmu_cache()" that architectures
1663 * with external mmu caches can use to update those (ie the Sparc or
1664 * PowerPC hashed page tables that act as extended TLBs).
1666 * Note the "page_table_lock". It is to protect against kswapd removing
1667 * pages from under us. Note that kswapd only ever _removes_ pages, never
1668 * adds them. As such, once we have noticed that the page is not present,
1669 * we can drop the lock early.
1671 * The adding of pages is protected by the MM semaphore (which we hold),
1672 * so we don't need to worry about a page being suddenly been added into
1675 * We enter with the pagetable spinlock held, we are supposed to
1676 * release it when done.
1678 static inline int handle_pte_fault(struct mm_struct *mm,
1679 struct vm_area_struct * vma, unsigned long address,
1680 int write_access, pte_t *pte, pmd_t *pmd)
1685 if (!pte_present(entry)) {
1687 * If it truly wasn't present, we know that kswapd
1688 * and the PTE updates will not touch it later. So
1691 if (pte_none(entry))
1692 return do_no_page(mm, vma, address, write_access, pte, pmd);
1693 if (pte_file(entry))
1694 return do_file_page(mm, vma, address, write_access, pte, pmd);
1695 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
1699 if (!pte_write(entry))
1700 return do_wp_page(mm, vma, address, pte, pmd, entry);
1702 entry = pte_mkdirty(entry);
1704 entry = pte_mkyoung(entry);
1705 ptep_set_access_flags(vma, address, pte, entry, write_access);
1706 update_mmu_cache(vma, address, entry);
1708 spin_unlock(&mm->page_table_lock);
1709 return VM_FAULT_MINOR;
1713 * By the time we get here, we already hold the mm semaphore
1715 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
1716 unsigned long address, int write_access)
1721 __set_current_state(TASK_RUNNING);
1722 pgd = pgd_offset(mm, address);
1724 inc_page_state(pgfault);
1726 if (is_vm_hugetlb_page(vma))
1727 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
1730 * We need the page table lock to synchronize with kswapd
1731 * and the SMP-safe atomic PTE updates.
1733 set_delay_flag(current,PF_MEMIO);
1734 spin_lock(&mm->page_table_lock);
1735 pmd = pmd_alloc(mm, pgd, address);
1738 pte_t * pte = pte_alloc_map(mm, pmd, address);
1740 int rc = handle_pte_fault(mm, vma, address, write_access, pte, pmd);
1741 clear_delay_flag(current,PF_MEMIO);
1745 spin_unlock(&mm->page_table_lock);
1746 clear_delay_flag(current,PF_MEMIO);
1747 return VM_FAULT_OOM;
1751 * Allocate page middle directory.
1753 * We've already handled the fast-path in-line, and we own the
1756 * On a two-level page table, this ends up actually being entirely
1759 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1763 spin_unlock(&mm->page_table_lock);
1764 new = pmd_alloc_one(mm, address);
1765 spin_lock(&mm->page_table_lock);
1770 * Because we dropped the lock, we should re-check the
1771 * entry, as somebody else could have populated it..
1773 if (pgd_present(*pgd)) {
1777 pgd_populate(mm, pgd, new);
1779 return pmd_offset(pgd, address);
1782 int make_pages_present(unsigned long addr, unsigned long end)
1784 int ret, len, write;
1785 struct vm_area_struct * vma;
1787 vma = find_vma(current->mm, addr);
1790 write = (vma->vm_flags & VM_WRITE) != 0;
1793 if (end > vma->vm_end)
1795 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
1796 ret = get_user_pages(current, current->mm, addr,
1797 len, write, 0, NULL, NULL);
1800 return ret == len ? 0 : -1;
1804 * Map a vmalloc()-space virtual address to the physical page.
1806 struct page * vmalloc_to_page(void * vmalloc_addr)
1808 unsigned long addr = (unsigned long) vmalloc_addr;
1809 struct page *page = NULL;
1810 pgd_t *pgd = pgd_offset_k(addr);
1814 if (!pgd_none(*pgd)) {
1815 pmd = pmd_offset(pgd, addr);
1816 if (!pmd_none(*pmd)) {
1818 ptep = pte_offset_map(pmd, addr);
1820 if (pte_present(pte))
1821 page = pte_page(pte);
1829 EXPORT_SYMBOL(vmalloc_to_page);
1831 #if !defined(CONFIG_ARCH_GATE_AREA)
1833 #if defined(AT_SYSINFO_EHDR)
1834 struct vm_area_struct gate_vma;
1836 static int __init gate_vma_init(void)
1838 gate_vma.vm_mm = NULL;
1839 gate_vma.vm_start = FIXADDR_USER_START;
1840 gate_vma.vm_end = FIXADDR_USER_END;
1841 gate_vma.vm_page_prot = PAGE_READONLY;
1842 gate_vma.vm_flags = 0;
1845 __initcall(gate_vma_init);
1848 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
1850 #ifdef AT_SYSINFO_EHDR
1857 int in_gate_area(struct task_struct *task, unsigned long addr)
1859 #ifdef AT_SYSINFO_EHDR
1860 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))