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 struct page *highmem_start_page;
72 EXPORT_SYMBOL(num_physpages);
73 EXPORT_SYMBOL(highmem_start_page);
74 EXPORT_SYMBOL(high_memory);
77 * We special-case the C-O-W ZERO_PAGE, because it's such
78 * a common occurrence (no need to read the page to know
79 * that it's zero - better for the cache and memory subsystem).
81 static inline void copy_cow_page(struct page * from, struct page * to, unsigned long address)
83 if (from == ZERO_PAGE(address)) {
84 clear_user_highpage(to, address);
87 copy_user_highpage(to, from, address);
91 * Note: this doesn't free the actual pages themselves. That
92 * has been handled earlier when unmapping all the memory regions.
94 static inline void free_one_pmd(struct mmu_gather *tlb, pmd_t * dir)
100 if (unlikely(pmd_bad(*dir))) {
105 page = pmd_page(*dir);
107 dec_page_state(nr_page_table_pages);
108 pte_free_tlb(tlb, page);
111 static inline void free_one_pgd(struct mmu_gather *tlb, pgd_t * dir,
119 if (unlikely(pgd_bad(*dir))) {
124 pmd = pmd_offset(dir, 0);
126 for (j = 0; j < PTRS_PER_PMD ; j++) {
127 if (pgd_idx * PGDIR_SIZE + j * PMD_SIZE >= TASK_SIZE)
129 free_one_pmd(tlb, pmd+j);
131 pmd_free_tlb(tlb, pmd);
135 * This function clears all user-level page tables of a process - this
136 * is needed by execve(), so that old pages aren't in the way.
138 * Must be called with pagetable lock held.
140 void clear_page_tables(struct mmu_gather *tlb, unsigned long first, int nr)
142 pgd_t * page_dir = tlb->mm->pgd;
147 free_one_pgd(tlb, page_dir, pgd_idx);
153 pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
155 if (!pmd_present(*pmd)) {
158 spin_unlock(&mm->page_table_lock);
159 new = pte_alloc_one(mm, address);
160 spin_lock(&mm->page_table_lock);
165 * Because we dropped the lock, we should re-check the
166 * entry, as somebody else could have populated it..
168 if (pmd_present(*pmd)) {
172 inc_page_state(nr_page_table_pages);
173 pmd_populate(mm, pmd, new);
176 return pte_offset_map(pmd, address);
179 pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
181 if (!pmd_present(*pmd)) {
184 spin_unlock(&mm->page_table_lock);
185 new = pte_alloc_one_kernel(mm, address);
186 spin_lock(&mm->page_table_lock);
191 * Because we dropped the lock, we should re-check the
192 * entry, as somebody else could have populated it..
194 if (pmd_present(*pmd)) {
195 pte_free_kernel(new);
198 pmd_populate_kernel(mm, pmd, new);
201 return pte_offset_kernel(pmd, address);
203 #define PTE_TABLE_MASK ((PTRS_PER_PTE-1) * sizeof(pte_t))
204 #define PMD_TABLE_MASK ((PTRS_PER_PMD-1) * sizeof(pmd_t))
207 * copy one vm_area from one task to the other. Assumes the page tables
208 * already present in the new task to be cleared in the whole range
209 * covered by this vma.
211 * 08Jan98 Merged into one routine from several inline routines to reduce
212 * variable count and make things faster. -jj
214 * dst->page_table_lock is held on entry and exit,
215 * but may be dropped within pmd_alloc() and pte_alloc_map().
217 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
218 struct vm_area_struct *vma)
220 pgd_t * src_pgd, * dst_pgd;
221 unsigned long address = vma->vm_start;
222 unsigned long end = vma->vm_end;
225 if (is_vm_hugetlb_page(vma))
226 return copy_hugetlb_page_range(dst, src, vma);
228 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
229 src_pgd = pgd_offset(src, address)-1;
230 dst_pgd = pgd_offset(dst, address)-1;
233 pmd_t * src_pmd, * dst_pmd;
235 src_pgd++; dst_pgd++;
239 if (pgd_none(*src_pgd))
240 goto skip_copy_pmd_range;
241 if (unlikely(pgd_bad(*src_pgd))) {
244 skip_copy_pmd_range: address = (address + PGDIR_SIZE) & PGDIR_MASK;
245 if (!address || (address >= end))
250 src_pmd = pmd_offset(src_pgd, address);
251 dst_pmd = pmd_alloc(dst, dst_pgd, address);
256 pte_t * src_pte, * dst_pte;
260 if (pmd_none(*src_pmd))
261 goto skip_copy_pte_range;
262 if (unlikely(pmd_bad(*src_pmd))) {
266 address = (address + PMD_SIZE) & PMD_MASK;
269 goto cont_copy_pmd_range;
272 dst_pte = pte_alloc_map(dst, dst_pmd, address);
275 spin_lock(&src->page_table_lock);
276 src_pte = pte_offset_map_nested(src_pmd, address);
278 pte_t pte = *src_pte;
282 if (!vx_rsspages_avail(dst, 1)) {
283 spin_unlock(&src->page_table_lock);
289 goto cont_copy_pte_range_noset;
290 /* pte contains position in swap, so copy. */
291 if (!pte_present(pte)) {
293 swap_duplicate(pte_to_swp_entry(pte));
294 set_pte(dst_pte, pte);
295 goto cont_copy_pte_range_noset;
298 /* the pte points outside of valid memory, the
299 * mapping is assumed to be good, meaningful
300 * and not mapped via rmap - duplicate the
305 page = pfn_to_page(pfn);
307 if (!page || PageReserved(page)) {
308 set_pte(dst_pte, pte);
309 goto cont_copy_pte_range_noset;
313 * If it's a COW mapping, write protect it both
314 * in the parent and the child
317 ptep_set_wrprotect(src_pte);
322 * If it's a shared mapping, mark it clean in
325 if (vma->vm_flags & VM_SHARED)
326 pte = pte_mkclean(pte);
327 pte = pte_mkold(pte);
330 vx_rsspages_inc(dst);
331 set_pte(dst_pte, pte);
333 cont_copy_pte_range_noset:
334 address += PAGE_SIZE;
335 if (address >= end) {
336 pte_unmap_nested(src_pte);
342 } while ((unsigned long)src_pte & PTE_TABLE_MASK);
343 pte_unmap_nested(src_pte-1);
344 pte_unmap(dst_pte-1);
345 spin_unlock(&src->page_table_lock);
346 cond_resched_lock(&dst->page_table_lock);
350 } while ((unsigned long)src_pmd & PMD_TABLE_MASK);
353 spin_unlock(&src->page_table_lock);
360 static void zap_pte_range(struct mmu_gather *tlb,
361 pmd_t *pmd, unsigned long address,
362 unsigned long size, struct zap_details *details)
364 unsigned long offset;
369 if (unlikely(pmd_bad(*pmd))) {
374 ptep = pte_offset_map(pmd, address);
375 offset = address & ~PMD_MASK;
376 if (offset + size > PMD_SIZE)
377 size = PMD_SIZE - offset;
379 if (details && !details->check_mapping && !details->nonlinear_vma)
381 for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) {
385 if (pte_present(pte)) {
386 struct page *page = NULL;
387 unsigned long pfn = pte_pfn(pte);
388 if (pfn_valid(pfn)) {
389 page = pfn_to_page(pfn);
390 if (PageReserved(page))
393 if (unlikely(details) && page) {
395 * unmap_shared_mapping_pages() wants to
396 * invalidate cache without truncating:
397 * unmap shared but keep private pages.
399 if (details->check_mapping &&
400 details->check_mapping != page->mapping)
403 * Each page->index must be checked when
404 * invalidating or truncating nonlinear.
406 if (details->nonlinear_vma &&
407 (page->index < details->first_index ||
408 page->index > details->last_index))
411 pte = ptep_get_and_clear(ptep);
412 tlb_remove_tlb_entry(tlb, ptep, address+offset);
415 if (unlikely(details) && details->nonlinear_vma
416 && linear_page_index(details->nonlinear_vma,
417 address+offset) != page->index)
418 set_pte(ptep, pgoff_to_pte(page->index));
420 set_page_dirty(page);
421 if (pte_young(pte) && page_mapping(page))
422 mark_page_accessed(page);
424 page_remove_rmap(page);
425 tlb_remove_page(tlb, page);
429 * If details->check_mapping, we leave swap entries;
430 * if details->nonlinear_vma, we leave file entries.
432 if (unlikely(details))
435 free_swap_and_cache(pte_to_swp_entry(pte));
441 static void zap_pmd_range(struct mmu_gather *tlb,
442 pgd_t * dir, unsigned long address,
443 unsigned long size, struct zap_details *details)
446 unsigned long end, pgd_boundary;
450 if (unlikely(pgd_bad(*dir))) {
455 pmd = pmd_offset(dir, address);
456 end = address + size;
457 pgd_boundary = ((address + PGDIR_SIZE) & PGDIR_MASK);
458 if (pgd_boundary && (end > pgd_boundary))
461 zap_pte_range(tlb, pmd, address, end - address, details);
462 address = (address + PMD_SIZE) & PMD_MASK;
464 } while (address && (address < end));
467 static void unmap_page_range(struct mmu_gather *tlb,
468 struct vm_area_struct *vma, unsigned long address,
469 unsigned long end, struct zap_details *details)
473 BUG_ON(address >= end);
474 dir = pgd_offset(vma->vm_mm, address);
475 tlb_start_vma(tlb, vma);
477 zap_pmd_range(tlb, dir, address, end - address, details);
478 address = (address + PGDIR_SIZE) & PGDIR_MASK;
480 } while (address && (address < end));
481 tlb_end_vma(tlb, vma);
484 /* Dispose of an entire struct mmu_gather per rescheduling point */
485 #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
486 #define ZAP_BLOCK_SIZE (FREE_PTE_NR * PAGE_SIZE)
489 /* For UP, 256 pages at a time gives nice low latency */
490 #if !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
491 #define ZAP_BLOCK_SIZE (256 * PAGE_SIZE)
494 /* No preempt: go for improved straight-line efficiency */
495 #if !defined(CONFIG_PREEMPT)
496 #define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
500 * unmap_vmas - unmap a range of memory covered by a list of vma's
501 * @tlbp: address of the caller's struct mmu_gather
502 * @mm: the controlling mm_struct
503 * @vma: the starting vma
504 * @start_addr: virtual address at which to start unmapping
505 * @end_addr: virtual address at which to end unmapping
506 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
507 * @details: details of nonlinear truncation or shared cache invalidation
509 * Returns the number of vma's which were covered by the unmapping.
511 * Unmap all pages in the vma list. Called under page_table_lock.
513 * We aim to not hold page_table_lock for too long (for scheduling latency
514 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
515 * return the ending mmu_gather to the caller.
517 * Only addresses between `start' and `end' will be unmapped.
519 * The VMA list must be sorted in ascending virtual address order.
521 * unmap_vmas() assumes that the caller will flush the whole unmapped address
522 * range after unmap_vmas() returns. So the only responsibility here is to
523 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
524 * drops the lock and schedules.
526 int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
527 struct vm_area_struct *vma, unsigned long start_addr,
528 unsigned long end_addr, unsigned long *nr_accounted,
529 struct zap_details *details)
531 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
532 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
533 int tlb_start_valid = 0;
535 int atomic = details && details->atomic;
537 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
541 start = max(vma->vm_start, start_addr);
542 if (start >= vma->vm_end)
544 end = min(vma->vm_end, end_addr);
545 if (end <= vma->vm_start)
548 if (vma->vm_flags & VM_ACCOUNT)
549 *nr_accounted += (end - start) >> PAGE_SHIFT;
552 while (start != end) {
555 if (!tlb_start_valid) {
560 if (is_vm_hugetlb_page(vma)) {
562 unmap_hugepage_range(vma, start, end);
564 block = min(zap_bytes, end - start);
565 unmap_page_range(*tlbp, vma, start,
566 start + block, details);
571 if ((long)zap_bytes > 0)
573 if (!atomic && need_resched()) {
574 int fullmm = tlb_is_full_mm(*tlbp);
575 tlb_finish_mmu(*tlbp, tlb_start, start);
576 cond_resched_lock(&mm->page_table_lock);
577 *tlbp = tlb_gather_mmu(mm, fullmm);
580 zap_bytes = ZAP_BLOCK_SIZE;
587 * zap_page_range - remove user pages in a given range
588 * @vma: vm_area_struct holding the applicable pages
589 * @address: starting address of pages to zap
590 * @size: number of bytes to zap
591 * @details: details of nonlinear truncation or shared cache invalidation
593 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
594 unsigned long size, struct zap_details *details)
596 struct mm_struct *mm = vma->vm_mm;
597 struct mmu_gather *tlb;
598 unsigned long end = address + size;
599 unsigned long nr_accounted = 0;
601 if (is_vm_hugetlb_page(vma)) {
602 zap_hugepage_range(vma, address, size);
607 spin_lock(&mm->page_table_lock);
608 tlb = tlb_gather_mmu(mm, 0);
609 unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
610 tlb_finish_mmu(tlb, address, end);
611 spin_unlock(&mm->page_table_lock);
615 * Do a quick page-table lookup for a single page.
616 * mm->page_table_lock must be held.
619 follow_page(struct mm_struct *mm, unsigned long address, int write)
627 page = follow_huge_addr(mm, address, write);
631 pgd = pgd_offset(mm, address);
632 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
635 pmd = pmd_offset(pgd, address);
639 return follow_huge_pmd(mm, address, pmd, write);
640 if (unlikely(pmd_bad(*pmd)))
643 ptep = pte_offset_map(pmd, address);
649 if (pte_present(pte)) {
650 if (write && !pte_write(pte))
652 if (write && !pte_dirty(pte)) {
653 struct page *page = pte_page(pte);
654 if (!PageDirty(page))
655 set_page_dirty(page);
658 if (pfn_valid(pfn)) {
659 struct page *page = pfn_to_page(pfn);
661 mark_page_accessed(page);
671 * Given a physical address, is there a useful struct page pointing to
672 * it? This may become more complex in the future if we start dealing
673 * with IO-aperture pages for direct-IO.
676 static inline struct page *get_page_map(struct page *page)
678 if (!pfn_valid(page_to_pfn(page)))
685 untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
686 unsigned long address)
691 /* Check if the vma is for an anonymous mapping. */
692 if (vma->vm_ops && vma->vm_ops->nopage)
695 /* Check if page directory entry exists. */
696 pgd = pgd_offset(mm, address);
697 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
700 /* Check if page middle directory entry exists. */
701 pmd = pmd_offset(pgd, address);
702 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
705 /* There is a pte slot for 'address' in 'mm'. */
710 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
711 unsigned long start, int len, int write, int force,
712 struct page **pages, struct vm_area_struct **vmas)
718 * Require read or write permissions.
719 * If 'force' is set, we only require the "MAY" flags.
721 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
722 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
726 struct vm_area_struct * vma;
728 vma = find_extend_vma(mm, start);
729 if (!vma && in_gate_area(tsk, start)) {
730 unsigned long pg = start & PAGE_MASK;
731 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
735 if (write) /* user gate pages are read-only */
736 return i ? : -EFAULT;
737 pgd = pgd_offset_k(pg);
739 return i ? : -EFAULT;
740 pmd = pmd_offset(pgd, pg);
742 return i ? : -EFAULT;
743 pte = pte_offset_kernel(pmd, pg);
744 if (!pte || !pte_present(*pte))
745 return i ? : -EFAULT;
747 pages[i] = pte_page(*pte);
758 if (!vma || (pages && (vma->vm_flags & VM_IO))
759 || !(flags & vma->vm_flags))
760 return i ? : -EFAULT;
762 if (is_vm_hugetlb_page(vma)) {
763 i = follow_hugetlb_page(mm, vma, pages, vmas,
767 spin_lock(&mm->page_table_lock);
770 int lookup_write = write;
771 while (!(map = follow_page(mm, start, lookup_write))) {
773 * Shortcut for anonymous pages. We don't want
774 * to force the creation of pages tables for
775 * insanly big anonymously mapped areas that
776 * nobody touched so far. This is important
777 * for doing a core dump for these mappings.
780 untouched_anonymous_page(mm,vma,start)) {
781 map = ZERO_PAGE(start);
784 spin_unlock(&mm->page_table_lock);
785 switch (handle_mm_fault(mm,vma,start,write)) {
792 case VM_FAULT_SIGBUS:
793 return i ? i : -EFAULT;
795 return i ? i : -ENOMEM;
800 * Now that we have performed a write fault
801 * and surely no longer have a shared page we
802 * shouldn't write, we shouldn't ignore an
803 * unwritable page in the page table if
804 * we are forcing write access.
806 lookup_write = write && !force;
807 spin_lock(&mm->page_table_lock);
810 pages[i] = get_page_map(map);
812 spin_unlock(&mm->page_table_lock);
814 page_cache_release(pages[i]);
818 flush_dcache_page(pages[i]);
819 if (!PageReserved(pages[i]))
820 page_cache_get(pages[i]);
827 } while(len && start < vma->vm_end);
828 spin_unlock(&mm->page_table_lock);
834 EXPORT_SYMBOL(get_user_pages);
836 static void zeromap_pte_range(pte_t * pte, unsigned long address,
837 unsigned long size, pgprot_t prot)
841 address &= ~PMD_MASK;
842 end = address + size;
846 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot));
847 BUG_ON(!pte_none(*pte));
848 set_pte(pte, zero_pte);
849 address += PAGE_SIZE;
851 } while (address && (address < end));
854 static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address,
855 unsigned long size, pgprot_t prot)
857 unsigned long base, end;
859 base = address & PGDIR_MASK;
860 address &= ~PGDIR_MASK;
861 end = address + size;
862 if (end > PGDIR_SIZE)
865 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
868 zeromap_pte_range(pte, base + address, end - address, prot);
870 address = (address + PMD_SIZE) & PMD_MASK;
872 } while (address && (address < end));
876 int zeromap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, pgprot_t prot)
880 unsigned long beg = address;
881 unsigned long end = address + size;
882 struct mm_struct *mm = vma->vm_mm;
884 dir = pgd_offset(mm, address);
885 flush_cache_range(vma, beg, end);
889 spin_lock(&mm->page_table_lock);
891 pmd_t *pmd = pmd_alloc(mm, dir, address);
895 error = zeromap_pmd_range(mm, pmd, address, end - address, prot);
898 address = (address + PGDIR_SIZE) & PGDIR_MASK;
900 } while (address && (address < end));
902 * Why flush? zeromap_pte_range has a BUG_ON for !pte_none()
904 flush_tlb_range(vma, beg, end);
905 spin_unlock(&mm->page_table_lock);
910 * maps a range of physical memory into the requested pages. the old
911 * mappings are removed. any references to nonexistent pages results
912 * in null mappings (currently treated as "copy-on-access")
914 static inline void remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
915 unsigned long phys_addr, pgprot_t prot)
920 address &= ~PMD_MASK;
921 end = address + size;
924 pfn = phys_addr >> PAGE_SHIFT;
926 BUG_ON(!pte_none(*pte));
927 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
928 set_pte(pte, pfn_pte(pfn, prot));
929 address += PAGE_SIZE;
932 } while (address && (address < end));
935 static inline int remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
936 unsigned long phys_addr, pgprot_t prot)
938 unsigned long base, end;
940 base = address & PGDIR_MASK;
941 address &= ~PGDIR_MASK;
942 end = address + size;
943 if (end > PGDIR_SIZE)
945 phys_addr -= address;
947 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
950 remap_pte_range(pte, base + address, end - address, address + phys_addr, prot);
952 address = (address + PMD_SIZE) & PMD_MASK;
954 } while (address && (address < end));
958 /* Note: this is only safe if the mm semaphore is held when called. */
959 int remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long phys_addr, unsigned long size, pgprot_t prot)
963 unsigned long beg = from;
964 unsigned long end = from + size;
965 struct mm_struct *mm = vma->vm_mm;
968 dir = pgd_offset(mm, from);
969 flush_cache_range(vma, beg, end);
973 spin_lock(&mm->page_table_lock);
975 pmd_t *pmd = pmd_alloc(mm, dir, from);
979 error = remap_pmd_range(mm, pmd, from, end - from, phys_addr + from, prot);
982 from = (from + PGDIR_SIZE) & PGDIR_MASK;
984 } while (from && (from < end));
986 * Why flush? remap_pte_range has a BUG_ON for !pte_none()
988 flush_tlb_range(vma, beg, end);
989 spin_unlock(&mm->page_table_lock);
993 EXPORT_SYMBOL(remap_page_range);
996 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
997 * servicing faults for write access. In the normal case, do always want
998 * pte_mkwrite. But get_user_pages can cause write faults for mappings
999 * that do not have writing enabled, when used by access_process_vm.
1001 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1003 if (likely(vma->vm_flags & VM_WRITE))
1004 pte = pte_mkwrite(pte);
1009 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1011 static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
1016 flush_cache_page(vma, address);
1017 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
1019 ptep_establish(vma, address, page_table, entry);
1020 update_mmu_cache(vma, address, entry);
1024 * This routine handles present pages, when users try to write
1025 * to a shared page. It is done by copying the page to a new address
1026 * and decrementing the shared-page counter for the old page.
1028 * Goto-purists beware: the only reason for goto's here is that it results
1029 * in better assembly code.. The "default" path will see no jumps at all.
1031 * Note that this routine assumes that the protection checks have been
1032 * done by the caller (the low-level page fault routine in most cases).
1033 * Thus we can safely just mark it writable once we've done any necessary
1036 * We also mark the page dirty at this point even though the page will
1037 * change only once the write actually happens. This avoids a few races,
1038 * and potentially makes it more efficient.
1040 * We hold the mm semaphore and the page_table_lock on entry and exit
1041 * with the page_table_lock released.
1043 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
1044 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
1046 struct page *old_page, *new_page;
1047 unsigned long pfn = pte_pfn(pte);
1050 if (unlikely(!pfn_valid(pfn))) {
1052 * This should really halt the system so it can be debugged or
1053 * at least the kernel stops what it's doing before it corrupts
1054 * data, but for the moment just pretend this is OOM.
1056 pte_unmap(page_table);
1057 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
1059 spin_unlock(&mm->page_table_lock);
1060 return VM_FAULT_OOM;
1062 old_page = pfn_to_page(pfn);
1064 if (!TestSetPageLocked(old_page)) {
1065 int reuse = can_share_swap_page(old_page);
1066 unlock_page(old_page);
1068 flush_cache_page(vma, address);
1069 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
1071 ptep_set_access_flags(vma, address, page_table, entry, 1);
1072 update_mmu_cache(vma, address, entry);
1073 pte_unmap(page_table);
1074 spin_unlock(&mm->page_table_lock);
1075 return VM_FAULT_MINOR;
1078 pte_unmap(page_table);
1081 * Ok, we need to copy. Oh, well..
1083 page_cache_get(old_page);
1084 spin_unlock(&mm->page_table_lock);
1086 if (unlikely(anon_vma_prepare(vma)))
1088 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1091 copy_cow_page(old_page,new_page,address);
1094 * Re-check the pte - we dropped the lock
1096 spin_lock(&mm->page_table_lock);
1097 page_table = pte_offset_map(pmd, address);
1098 if (likely(pte_same(*page_table, pte))) {
1099 if (PageReserved(old_page))
1101 vx_rsspages_inc(mm);
1103 page_remove_rmap(old_page);
1104 break_cow(vma, new_page, address, page_table);
1105 lru_cache_add_active(new_page);
1106 page_add_anon_rmap(new_page, vma, address);
1108 /* Free the old page.. */
1109 new_page = old_page;
1111 pte_unmap(page_table);
1112 page_cache_release(new_page);
1113 page_cache_release(old_page);
1114 spin_unlock(&mm->page_table_lock);
1115 return VM_FAULT_MINOR;
1118 page_cache_release(old_page);
1119 return VM_FAULT_OOM;
1123 * Helper function for unmap_mapping_range().
1125 static inline void unmap_mapping_range_list(struct prio_tree_root *root,
1126 struct zap_details *details)
1128 struct vm_area_struct *vma = NULL;
1129 struct prio_tree_iter iter;
1130 pgoff_t vba, vea, zba, zea;
1132 while ((vma = vma_prio_tree_next(vma, root, &iter,
1133 details->first_index, details->last_index)) != NULL) {
1134 vba = vma->vm_pgoff;
1135 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1136 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1137 zba = details->first_index;
1140 zea = details->last_index;
1144 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1145 (zea - zba + 1) << PAGE_SHIFT, details);
1150 * unmap_mapping_range - unmap the portion of all mmaps
1151 * in the specified address_space corresponding to the specified
1152 * page range in the underlying file.
1153 * @address_space: the address space containing mmaps to be unmapped.
1154 * @holebegin: byte in first page to unmap, relative to the start of
1155 * the underlying file. This will be rounded down to a PAGE_SIZE
1156 * boundary. Note that this is different from vmtruncate(), which
1157 * must keep the partial page. In contrast, we must get rid of
1159 * @holelen: size of prospective hole in bytes. This will be rounded
1160 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1162 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1163 * but 0 when invalidating pagecache, don't throw away private data.
1165 void unmap_mapping_range(struct address_space *mapping,
1166 loff_t const holebegin, loff_t const holelen, int even_cows)
1168 struct zap_details details;
1169 pgoff_t hba = holebegin >> PAGE_SHIFT;
1170 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1172 /* Check for overflow. */
1173 if (sizeof(holelen) > sizeof(hlen)) {
1175 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1176 if (holeend & ~(long long)ULONG_MAX)
1177 hlen = ULONG_MAX - hba + 1;
1180 details.check_mapping = even_cows? NULL: mapping;
1181 details.nonlinear_vma = NULL;
1182 details.first_index = hba;
1183 details.last_index = hba + hlen - 1;
1184 details.atomic = 1; /* A spinlock is held */
1185 if (details.last_index < details.first_index)
1186 details.last_index = ULONG_MAX;
1188 spin_lock(&mapping->i_mmap_lock);
1189 /* Protect against page fault */
1190 atomic_inc(&mapping->truncate_count);
1192 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1193 unmap_mapping_range_list(&mapping->i_mmap, &details);
1196 * In nonlinear VMAs there is no correspondence between virtual address
1197 * offset and file offset. So we must perform an exhaustive search
1198 * across *all* the pages in each nonlinear VMA, not just the pages
1199 * whose virtual address lies outside the file truncation point.
1201 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) {
1202 struct vm_area_struct *vma;
1203 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
1204 shared.vm_set.list) {
1205 details.nonlinear_vma = vma;
1206 zap_page_range(vma, vma->vm_start,
1207 vma->vm_end - vma->vm_start, &details);
1210 spin_unlock(&mapping->i_mmap_lock);
1212 EXPORT_SYMBOL(unmap_mapping_range);
1215 * Handle all mappings that got truncated by a "truncate()"
1218 * NOTE! We have to be ready to update the memory sharing
1219 * between the file and the memory map for a potential last
1220 * incomplete page. Ugly, but necessary.
1222 int vmtruncate(struct inode * inode, loff_t offset)
1224 struct address_space *mapping = inode->i_mapping;
1225 unsigned long limit;
1227 if (inode->i_size < offset)
1229 i_size_write(inode, offset);
1230 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1231 truncate_inode_pages(mapping, offset);
1235 limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
1236 if (limit != RLIM_INFINITY && offset > limit)
1238 if (offset > inode->i_sb->s_maxbytes)
1240 i_size_write(inode, offset);
1243 if (inode->i_op && inode->i_op->truncate)
1244 inode->i_op->truncate(inode);
1247 send_sig(SIGXFSZ, current, 0);
1252 EXPORT_SYMBOL(vmtruncate);
1255 * Primitive swap readahead code. We simply read an aligned block of
1256 * (1 << page_cluster) entries in the swap area. This method is chosen
1257 * because it doesn't cost us any seek time. We also make sure to queue
1258 * the 'original' request together with the readahead ones...
1260 * This has been extended to use the NUMA policies from the mm triggering
1263 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1265 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1268 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1271 struct page *new_page;
1272 unsigned long offset;
1275 * Get the number of handles we should do readahead io to.
1277 num = valid_swaphandles(entry, &offset);
1278 for (i = 0; i < num; offset++, i++) {
1279 /* Ok, do the async read-ahead now */
1280 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1281 offset), vma, addr);
1284 page_cache_release(new_page);
1287 * Find the next applicable VMA for the NUMA policy.
1293 if (addr >= vma->vm_end) {
1295 next_vma = vma ? vma->vm_next : NULL;
1297 if (vma && addr < vma->vm_start)
1300 if (next_vma && addr >= next_vma->vm_start) {
1302 next_vma = vma->vm_next;
1307 lru_add_drain(); /* Push any new pages onto the LRU now */
1311 * We hold the mm semaphore and the page_table_lock on entry and
1312 * should release the pagetable lock on exit..
1314 static int do_swap_page(struct mm_struct * mm,
1315 struct vm_area_struct * vma, unsigned long address,
1316 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
1319 swp_entry_t entry = pte_to_swp_entry(orig_pte);
1321 int ret = VM_FAULT_MINOR;
1323 pte_unmap(page_table);
1324 spin_unlock(&mm->page_table_lock);
1325 page = lookup_swap_cache(entry);
1327 swapin_readahead(entry, address, vma);
1328 page = read_swap_cache_async(entry, vma, address);
1331 * Back out if somebody else faulted in this pte while
1332 * we released the page table lock.
1334 spin_lock(&mm->page_table_lock);
1335 page_table = pte_offset_map(pmd, address);
1336 if (likely(pte_same(*page_table, orig_pte)))
1339 ret = VM_FAULT_MINOR;
1340 pte_unmap(page_table);
1341 spin_unlock(&mm->page_table_lock);
1345 /* Had to read the page from swap area: Major fault */
1346 ret = VM_FAULT_MAJOR;
1347 inc_page_state(pgmajfault);
1350 if (!vx_rsspages_avail(mm, 1)) {
1354 mark_page_accessed(page);
1358 * Back out if somebody else faulted in this pte while we
1359 * released the page table lock.
1361 spin_lock(&mm->page_table_lock);
1362 page_table = pte_offset_map(pmd, address);
1363 if (unlikely(!pte_same(*page_table, orig_pte))) {
1364 pte_unmap(page_table);
1365 spin_unlock(&mm->page_table_lock);
1367 page_cache_release(page);
1368 ret = VM_FAULT_MINOR;
1372 /* The page isn't present yet, go ahead with the fault. */
1376 remove_exclusive_swap_page(page);
1379 vx_rsspages_inc(mm);
1380 pte = mk_pte(page, vma->vm_page_prot);
1381 if (write_access && can_share_swap_page(page)) {
1382 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1387 flush_icache_page(vma, page);
1388 set_pte(page_table, pte);
1389 page_add_anon_rmap(page, vma, address);
1392 if (do_wp_page(mm, vma, address,
1393 page_table, pmd, pte) == VM_FAULT_OOM)
1398 /* No need to invalidate - it was non-present before */
1399 update_mmu_cache(vma, address, pte);
1400 pte_unmap(page_table);
1401 spin_unlock(&mm->page_table_lock);
1407 * We are called with the MM semaphore and page_table_lock
1408 * spinlock held to protect against concurrent faults in
1409 * multithreaded programs.
1412 do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1413 pte_t *page_table, pmd_t *pmd, int write_access,
1417 struct page * page = ZERO_PAGE(addr);
1419 if (!vx_rsspages_avail(mm, 1)) {
1420 spin_unlock(&mm->page_table_lock);
1421 return VM_FAULT_OOM;
1424 /* Read-only mapping of ZERO_PAGE. */
1425 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
1427 /* ..except if it's a write access */
1429 /* Allocate our own private page. */
1430 pte_unmap(page_table);
1431 spin_unlock(&mm->page_table_lock);
1433 if (unlikely(anon_vma_prepare(vma)))
1435 page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
1438 clear_user_highpage(page, addr);
1440 spin_lock(&mm->page_table_lock);
1441 page_table = pte_offset_map(pmd, addr);
1443 if (!pte_none(*page_table)) {
1444 pte_unmap(page_table);
1445 page_cache_release(page);
1446 spin_unlock(&mm->page_table_lock);
1450 vx_rsspages_inc(mm);
1451 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
1452 vma->vm_page_prot)),
1454 lru_cache_add_active(page);
1455 mark_page_accessed(page);
1456 page_add_anon_rmap(page, vma, addr);
1459 set_pte(page_table, entry);
1460 pte_unmap(page_table);
1462 /* No need to invalidate - it was non-present before */
1463 update_mmu_cache(vma, addr, entry);
1464 spin_unlock(&mm->page_table_lock);
1466 return VM_FAULT_MINOR;
1468 return VM_FAULT_OOM;
1472 * do_no_page() tries to create a new page mapping. It aggressively
1473 * tries to share with existing pages, but makes a separate copy if
1474 * the "write_access" parameter is true in order to avoid the next
1477 * As this is called only for pages that do not currently exist, we
1478 * do not need to flush old virtual caches or the TLB.
1480 * This is called with the MM semaphore held and the page table
1481 * spinlock held. Exit with the spinlock released.
1484 do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1485 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
1487 struct page * new_page;
1488 struct address_space *mapping = NULL;
1491 int ret = VM_FAULT_MINOR;
1494 if (!vma->vm_ops || !vma->vm_ops->nopage)
1495 return do_anonymous_page(mm, vma, page_table,
1496 pmd, write_access, address);
1497 pte_unmap(page_table);
1498 spin_unlock(&mm->page_table_lock);
1501 mapping = vma->vm_file->f_mapping;
1502 sequence = atomic_read(&mapping->truncate_count);
1504 smp_rmb(); /* Prevent CPU from reordering lock-free ->nopage() */
1506 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1508 /* no page was available -- either SIGBUS or OOM */
1509 if (new_page == NOPAGE_SIGBUS)
1510 return VM_FAULT_SIGBUS;
1511 if (new_page == NOPAGE_OOM)
1512 return VM_FAULT_OOM;
1513 if (!vx_rsspages_avail(mm, 1))
1514 return VM_FAULT_OOM;
1517 * Should we do an early C-O-W break?
1519 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1522 if (unlikely(anon_vma_prepare(vma)))
1524 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1527 copy_user_highpage(page, new_page, address);
1528 page_cache_release(new_page);
1533 spin_lock(&mm->page_table_lock);
1535 * For a file-backed vma, someone could have truncated or otherwise
1536 * invalidated this page. If unmap_mapping_range got called,
1537 * retry getting the page.
1540 (unlikely(sequence != atomic_read(&mapping->truncate_count)))) {
1541 sequence = atomic_read(&mapping->truncate_count);
1542 spin_unlock(&mm->page_table_lock);
1543 page_cache_release(new_page);
1546 page_table = pte_offset_map(pmd, address);
1549 * This silly early PAGE_DIRTY setting removes a race
1550 * due to the bad i386 page protection. But it's valid
1551 * for other architectures too.
1553 * Note that if write_access is true, we either now have
1554 * an exclusive copy of the page, or this is a shared mapping,
1555 * so we can make it writable and dirty to avoid having to
1556 * handle that later.
1558 /* Only go through if we didn't race with anybody else... */
1559 if (pte_none(*page_table)) {
1560 if (!PageReserved(new_page))
1562 vx_rsspages_inc(mm);
1563 flush_icache_page(vma, new_page);
1564 entry = mk_pte(new_page, vma->vm_page_prot);
1566 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1567 set_pte(page_table, entry);
1569 lru_cache_add_active(new_page);
1570 page_add_anon_rmap(new_page, vma, address);
1572 page_add_file_rmap(new_page);
1573 pte_unmap(page_table);
1575 /* One of our sibling threads was faster, back out. */
1576 pte_unmap(page_table);
1577 page_cache_release(new_page);
1578 spin_unlock(&mm->page_table_lock);
1582 /* no need to invalidate: a not-present page shouldn't be cached */
1583 update_mmu_cache(vma, address, entry);
1584 spin_unlock(&mm->page_table_lock);
1588 page_cache_release(new_page);
1594 * Fault of a previously existing named mapping. Repopulate the pte
1595 * from the encoded file_pte if possible. This enables swappable
1598 static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
1599 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
1601 unsigned long pgoff;
1604 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
1606 * Fall back to the linear mapping if the fs does not support
1609 if (!vma->vm_ops || !vma->vm_ops->populate ||
1610 (write_access && !(vma->vm_flags & VM_SHARED))) {
1612 return do_no_page(mm, vma, address, write_access, pte, pmd);
1615 pgoff = pte_to_pgoff(*pte);
1618 spin_unlock(&mm->page_table_lock);
1620 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
1622 return VM_FAULT_OOM;
1624 return VM_FAULT_SIGBUS;
1625 return VM_FAULT_MAJOR;
1629 * These routines also need to handle stuff like marking pages dirty
1630 * and/or accessed for architectures that don't do it in hardware (most
1631 * RISC architectures). The early dirtying is also good on the i386.
1633 * There is also a hook called "update_mmu_cache()" that architectures
1634 * with external mmu caches can use to update those (ie the Sparc or
1635 * PowerPC hashed page tables that act as extended TLBs).
1637 * Note the "page_table_lock". It is to protect against kswapd removing
1638 * pages from under us. Note that kswapd only ever _removes_ pages, never
1639 * adds them. As such, once we have noticed that the page is not present,
1640 * we can drop the lock early.
1642 * The adding of pages is protected by the MM semaphore (which we hold),
1643 * so we don't need to worry about a page being suddenly been added into
1646 * We enter with the pagetable spinlock held, we are supposed to
1647 * release it when done.
1649 static inline int handle_pte_fault(struct mm_struct *mm,
1650 struct vm_area_struct * vma, unsigned long address,
1651 int write_access, pte_t *pte, pmd_t *pmd)
1656 if (!pte_present(entry)) {
1658 * If it truly wasn't present, we know that kswapd
1659 * and the PTE updates will not touch it later. So
1662 if (pte_none(entry))
1663 return do_no_page(mm, vma, address, write_access, pte, pmd);
1664 if (pte_file(entry))
1665 return do_file_page(mm, vma, address, write_access, pte, pmd);
1666 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
1670 if (!pte_write(entry))
1671 return do_wp_page(mm, vma, address, pte, pmd, entry);
1673 entry = pte_mkdirty(entry);
1675 entry = pte_mkyoung(entry);
1676 ptep_set_access_flags(vma, address, pte, entry, write_access);
1677 update_mmu_cache(vma, address, entry);
1679 spin_unlock(&mm->page_table_lock);
1680 return VM_FAULT_MINOR;
1684 * By the time we get here, we already hold the mm semaphore
1686 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
1687 unsigned long address, int write_access)
1692 __set_current_state(TASK_RUNNING);
1693 pgd = pgd_offset(mm, address);
1695 inc_page_state(pgfault);
1697 if (is_vm_hugetlb_page(vma))
1698 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
1701 * We need the page table lock to synchronize with kswapd
1702 * and the SMP-safe atomic PTE updates.
1704 spin_lock(&mm->page_table_lock);
1705 pmd = pmd_alloc(mm, pgd, address);
1708 pte_t * pte = pte_alloc_map(mm, pmd, address);
1710 return handle_pte_fault(mm, vma, address, write_access, pte, pmd);
1712 spin_unlock(&mm->page_table_lock);
1713 return VM_FAULT_OOM;
1717 * Allocate page middle directory.
1719 * We've already handled the fast-path in-line, and we own the
1722 * On a two-level page table, this ends up actually being entirely
1725 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
1729 spin_unlock(&mm->page_table_lock);
1730 new = pmd_alloc_one(mm, address);
1731 spin_lock(&mm->page_table_lock);
1736 * Because we dropped the lock, we should re-check the
1737 * entry, as somebody else could have populated it..
1739 if (pgd_present(*pgd)) {
1743 pgd_populate(mm, pgd, new);
1745 return pmd_offset(pgd, address);
1748 int make_pages_present(unsigned long addr, unsigned long end)
1750 int ret, len, write;
1751 struct vm_area_struct * vma;
1753 vma = find_vma(current->mm, addr);
1754 write = (vma->vm_flags & VM_WRITE) != 0;
1757 if (end > vma->vm_end)
1759 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
1760 ret = get_user_pages(current, current->mm, addr,
1761 len, write, 0, NULL, NULL);
1764 return ret == len ? 0 : -1;
1768 * Map a vmalloc()-space virtual address to the physical page.
1770 struct page * vmalloc_to_page(void * vmalloc_addr)
1772 unsigned long addr = (unsigned long) vmalloc_addr;
1773 struct page *page = NULL;
1774 pgd_t *pgd = pgd_offset_k(addr);
1778 if (!pgd_none(*pgd)) {
1779 pmd = pmd_offset(pgd, addr);
1780 if (!pmd_none(*pmd)) {
1782 ptep = pte_offset_map(pmd, addr);
1784 if (pte_present(pte))
1785 page = pte_page(pte);
1793 EXPORT_SYMBOL(vmalloc_to_page);
1795 #if !defined(CONFIG_ARCH_GATE_AREA)
1797 #if defined(AT_SYSINFO_EHDR)
1798 struct vm_area_struct gate_vma;
1800 static int __init gate_vma_init(void)
1802 gate_vma.vm_mm = NULL;
1803 gate_vma.vm_start = FIXADDR_USER_START;
1804 gate_vma.vm_end = FIXADDR_USER_END;
1805 gate_vma.vm_page_prot = PAGE_READONLY;
1806 gate_vma.vm_flags = 0;
1809 __initcall(gate_vma_init);
1812 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
1814 #ifdef AT_SYSINFO_EHDR
1821 int in_gate_area(struct task_struct *task, unsigned long addr)
1823 #ifdef AT_SYSINFO_EHDR
1824 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))