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705e87c0c3
Convert those common loops using page_table_lock on the outside and pte_offset_map within to use just pte_offset_map_lock within instead. These all hold mmap_sem (some exclusively, some not), so at no level can a page table be whipped away from beneath them. But whereas pte_alloc loops tested with the "atomic" pmd_present, these loops are testing with pmd_none, which on i386 PAE tests both lower and upper halves. That's now unsafe, so add a cast into pmd_none to test only the vital lower half: we lose a little sensitivity to a corrupt middle directory, but not enough to worry about. It appears that i386 and UML were the only architectures vulnerable in this way, and pgd and pud no problem. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
432 lines
12 KiB
C
432 lines
12 KiB
C
/*
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* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Copyright 2003 PathScale, Inc.
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* Derived from include/asm-i386/pgtable.h
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* Licensed under the GPL
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*/
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#ifndef __UM_PGTABLE_H
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#define __UM_PGTABLE_H
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#include "linux/sched.h"
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#include "linux/linkage.h"
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#include "asm/processor.h"
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#include "asm/page.h"
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#include "asm/fixmap.h"
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#define _PAGE_PRESENT 0x001
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#define _PAGE_NEWPAGE 0x002
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#define _PAGE_NEWPROT 0x004
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#define _PAGE_RW 0x020
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#define _PAGE_USER 0x040
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#define _PAGE_ACCESSED 0x080
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#define _PAGE_DIRTY 0x100
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/* If _PAGE_PRESENT is clear, we use these: */
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#define _PAGE_FILE 0x008 /* nonlinear file mapping, saved PTE; unset:swap */
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#define _PAGE_PROTNONE 0x010 /* if the user mapped it with PROT_NONE;
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pte_present gives true */
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#ifdef CONFIG_3_LEVEL_PGTABLES
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#include "asm/pgtable-3level.h"
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#else
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#include "asm/pgtable-2level.h"
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#endif
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extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
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extern void *um_virt_to_phys(struct task_struct *task, unsigned long virt,
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pte_t *pte_out);
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/* zero page used for uninitialized stuff */
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extern unsigned long *empty_zero_page;
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#define pgtable_cache_init() do ; while (0)
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/*
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* pgd entries used up by user/kernel:
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*/
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#define USER_PGD_PTRS (TASK_SIZE >> PGDIR_SHIFT)
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#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
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#ifndef __ASSEMBLY__
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/* Just any arbitrary offset to the start of the vmalloc VM area: the
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* current 8MB value just means that there will be a 8MB "hole" after the
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* physical memory until the kernel virtual memory starts. That means that
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* any out-of-bounds memory accesses will hopefully be caught.
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* The vmalloc() routines leaves a hole of 4kB between each vmalloced
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* area for the same reason. ;)
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*/
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extern unsigned long end_iomem;
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#define VMALLOC_OFFSET (__va_space)
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#define VMALLOC_START ((end_iomem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
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#ifdef CONFIG_HIGHMEM
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# define VMALLOC_END (PKMAP_BASE-2*PAGE_SIZE)
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#else
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# define VMALLOC_END (FIXADDR_START-2*PAGE_SIZE)
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#endif
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#define REGION_SHIFT (sizeof(pte_t) * 8 - 4)
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#define REGION_MASK (((unsigned long) 0xf) << REGION_SHIFT)
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#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
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#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
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#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
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#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
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#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
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#define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT | _PAGE_DIRTY | _PAGE_ACCESSED)
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/*
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* The i386 can't do page protection for execute, and considers that the same are read.
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* Also, write permissions imply read permissions. This is the closest we can get..
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*/
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#define __P000 PAGE_NONE
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#define __P001 PAGE_READONLY
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#define __P010 PAGE_COPY
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#define __P011 PAGE_COPY
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#define __P100 PAGE_READONLY
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#define __P101 PAGE_READONLY
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#define __P110 PAGE_COPY
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#define __P111 PAGE_COPY
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#define __S000 PAGE_NONE
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#define __S001 PAGE_READONLY
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#define __S010 PAGE_SHARED
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#define __S011 PAGE_SHARED
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#define __S100 PAGE_READONLY
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#define __S101 PAGE_READONLY
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#define __S110 PAGE_SHARED
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#define __S111 PAGE_SHARED
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/*
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* Define this if things work differently on an i386 and an i486:
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* it will (on an i486) warn about kernel memory accesses that are
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* done without a 'access_ok(VERIFY_WRITE,..)'
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*/
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#undef TEST_VERIFY_AREA
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/* page table for 0-4MB for everybody */
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extern unsigned long pg0[1024];
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/*
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* ZERO_PAGE is a global shared page that is always zero: used
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* for zero-mapped memory areas etc..
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*/
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#define ZERO_PAGE(vaddr) virt_to_page(empty_zero_page)
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/* number of bits that fit into a memory pointer */
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#define BITS_PER_PTR (8*sizeof(unsigned long))
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/* to align the pointer to a pointer address */
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#define PTR_MASK (~(sizeof(void*)-1))
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/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
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/* 64-bit machines, beware! SRB. */
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#define SIZEOF_PTR_LOG2 3
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/* to find an entry in a page-table */
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#define PAGE_PTR(address) \
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((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
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#define pte_clear(mm,addr,xp) pte_set_val(*(xp), (phys_t) 0, __pgprot(_PAGE_NEWPAGE))
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#define pmd_none(x) (!((unsigned long)pmd_val(x) & ~_PAGE_NEWPAGE))
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#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
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#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
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#define pmd_clear(xp) do { pmd_val(*(xp)) = _PAGE_NEWPAGE; } while (0)
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#define pmd_newpage(x) (pmd_val(x) & _PAGE_NEWPAGE)
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#define pmd_mkuptodate(x) (pmd_val(x) &= ~_PAGE_NEWPAGE)
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#define pud_newpage(x) (pud_val(x) & _PAGE_NEWPAGE)
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#define pud_mkuptodate(x) (pud_val(x) &= ~_PAGE_NEWPAGE)
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#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
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#define pmd_page(pmd) phys_to_page(pmd_val(pmd) & PAGE_MASK)
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#define pte_page(x) pfn_to_page(pte_pfn(x))
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#define pte_address(x) (__va(pte_val(x) & PAGE_MASK))
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#define mk_phys(a, r) ((a) + (((unsigned long) r) << REGION_SHIFT))
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#define phys_addr(p) ((p) & ~REGION_MASK)
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#define pte_present(x) pte_get_bits(x, (_PAGE_PRESENT | _PAGE_PROTNONE))
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/*
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* =================================
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* Flags checking section.
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* =================================
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*/
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static inline int pte_none(pte_t pte)
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{
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return pte_is_zero(pte);
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}
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/*
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* The following only work if pte_present() is true.
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* Undefined behaviour if not..
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*/
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static inline int pte_user(pte_t pte)
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{
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return((pte_get_bits(pte, _PAGE_USER)) &&
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!(pte_get_bits(pte, _PAGE_PROTNONE)));
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}
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static inline int pte_read(pte_t pte)
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{
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return((pte_get_bits(pte, _PAGE_USER)) &&
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!(pte_get_bits(pte, _PAGE_PROTNONE)));
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}
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static inline int pte_exec(pte_t pte){
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return((pte_get_bits(pte, _PAGE_USER)) &&
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!(pte_get_bits(pte, _PAGE_PROTNONE)));
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}
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static inline int pte_write(pte_t pte)
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{
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return((pte_get_bits(pte, _PAGE_RW)) &&
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!(pte_get_bits(pte, _PAGE_PROTNONE)));
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}
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/*
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* The following only works if pte_present() is not true.
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*/
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static inline int pte_file(pte_t pte)
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{
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return pte_get_bits(pte, _PAGE_FILE);
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}
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static inline int pte_dirty(pte_t pte)
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{
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return pte_get_bits(pte, _PAGE_DIRTY);
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}
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static inline int pte_young(pte_t pte)
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{
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return pte_get_bits(pte, _PAGE_ACCESSED);
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}
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static inline int pte_newpage(pte_t pte)
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{
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return pte_get_bits(pte, _PAGE_NEWPAGE);
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}
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static inline int pte_newprot(pte_t pte)
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{
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return(pte_present(pte) && (pte_get_bits(pte, _PAGE_NEWPROT)));
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}
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/*
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* =================================
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* Flags setting section.
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* =================================
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*/
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static inline pte_t pte_mknewprot(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_NEWPROT);
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return(pte);
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}
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static inline pte_t pte_rdprotect(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_USER);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_exprotect(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_USER);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_mkclean(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_DIRTY);
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return(pte);
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}
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static inline pte_t pte_mkold(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_ACCESSED);
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return(pte);
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}
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static inline pte_t pte_wrprotect(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_RW);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_mkread(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_RW);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_mkexec(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_USER);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_mkdirty(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_DIRTY);
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return(pte);
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}
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static inline pte_t pte_mkyoung(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_ACCESSED);
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return(pte);
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}
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static inline pte_t pte_mkwrite(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_RW);
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return(pte_mknewprot(pte));
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}
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static inline pte_t pte_mkuptodate(pte_t pte)
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{
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pte_clear_bits(pte, _PAGE_NEWPAGE);
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if(pte_present(pte))
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pte_clear_bits(pte, _PAGE_NEWPROT);
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return(pte);
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}
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static inline pte_t pte_mknewpage(pte_t pte)
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{
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pte_set_bits(pte, _PAGE_NEWPAGE);
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return(pte);
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}
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static inline void set_pte(pte_t *pteptr, pte_t pteval)
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{
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pte_copy(*pteptr, pteval);
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/* If it's a swap entry, it needs to be marked _PAGE_NEWPAGE so
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* fix_range knows to unmap it. _PAGE_NEWPROT is specific to
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* mapped pages.
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*/
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*pteptr = pte_mknewpage(*pteptr);
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if(pte_present(*pteptr)) *pteptr = pte_mknewprot(*pteptr);
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}
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#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
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/*
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* Conversion functions: convert a page and protection to a page entry,
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* and a page entry and page directory to the page they refer to.
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*/
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#define phys_to_page(phys) pfn_to_page(phys_to_pfn(phys))
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#define __virt_to_page(virt) phys_to_page(__pa(virt))
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#define page_to_phys(page) pfn_to_phys(page_to_pfn(page))
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#define mk_pte(page, pgprot) \
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({ pte_t pte; \
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\
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pte_set_val(pte, page_to_phys(page), (pgprot)); \
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if (pte_present(pte)) \
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pte_mknewprot(pte_mknewpage(pte)); \
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pte;})
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static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
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{
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pte_set_val(pte, (pte_val(pte) & _PAGE_CHG_MASK), newprot);
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return pte;
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}
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#define pmd_page_kernel(pmd) ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
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/*
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* the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
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*
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* this macro returns the index of the entry in the pgd page which would
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* control the given virtual address
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*/
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#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
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#define pgd_index_k(addr) pgd_index(addr)
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/*
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* pgd_offset() returns a (pgd_t *)
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* pgd_index() is used get the offset into the pgd page's array of pgd_t's;
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*/
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#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
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/*
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* a shortcut which implies the use of the kernel's pgd, instead
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* of a process's
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*/
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#define pgd_offset_k(address) pgd_offset(&init_mm, address)
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/*
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* the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
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*
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* this macro returns the index of the entry in the pmd page which would
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* control the given virtual address
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*/
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#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
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/*
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* the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
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*
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* this macro returns the index of the entry in the pte page which would
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* control the given virtual address
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*/
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#define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
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#define pte_offset_kernel(dir, address) \
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((pte_t *) pmd_page_kernel(*(dir)) + pte_index(address))
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#define pte_offset_map(dir, address) \
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((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
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#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
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#define pte_unmap(pte) do { } while (0)
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#define pte_unmap_nested(pte) do { } while (0)
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#define update_mmu_cache(vma,address,pte) do ; while (0)
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/* Encode and de-code a swap entry */
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#define __swp_type(x) (((x).val >> 4) & 0x3f)
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#define __swp_offset(x) ((x).val >> 11)
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#define __swp_entry(type, offset) \
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((swp_entry_t) { ((type) << 4) | ((offset) << 11) })
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#define __pte_to_swp_entry(pte) \
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((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
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#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
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#define kern_addr_valid(addr) (1)
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#include <asm-generic/pgtable.h>
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#include <asm-generic/pgtable-nopud.h>
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#endif
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#endif
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#define virt_to_page(addr) __virt_to_page((const unsigned long) addr)
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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