LXR linux/arch/x86/include/asm/pgtable-2level.h

   1#ifndef _ASM_X86_PGTABLE_2LEVEL_H
   2#define _ASM_X86_PGTABLE_2LEVEL_H
   3
   4#define pte_ERROR(e) \
   5        pr_err("%s:%d: bad pte %08lx\n", __FILE__, __LINE__, (e).pte_low)
   6#define pgd_ERROR(e) \
   7        pr_err("%s:%d: bad pgd %08lx\n", __FILE__, __LINE__, pgd_val(e))
   8
   9/*
  10 * Certain architectures need to do special things when PTEs
  11 * within a page table are directly modified.  Thus, the following
  12 * hook is made available.
  13 */
  14static inline void native_set_pte(pte_t *ptep , pte_t pte)
  15{
  16        *ptep = pte;
  17}
  18
  19static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
  20{
  21        *pmdp = pmd;
  22}
  23
  24static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
  25{
  26        native_set_pte(ptep, pte);
  27}
  28
  29static inline void native_pmd_clear(pmd_t *pmdp)
  30{
  31        native_set_pmd(pmdp, __pmd(0));
  32}
  33
  34static inline void native_pte_clear(struct mm_struct *mm,
  35                                    unsigned long addr, pte_t *xp)
  36{
  37        *xp = native_make_pte(0);
  38}
  39
  40#ifdef CONFIG_SMP
  41static inline pte_t native_ptep_get_and_clear(pte_t *xp)
  42{
  43        return __pte(xchg(&xp->pte_low, 0));
  44}
  45#else
  46#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
  47#endif
  48
  49#ifdef CONFIG_SMP
  50static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
  51{
  52        return __pmd(xchg((pmdval_t *)xp, 0));
  53}
  54#else
  55#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
  56#endif
  57
  58/* Bit manipulation helper on pte/pgoff entry */
  59static inline unsigned long pte_bitop(unsigned long value, unsigned int rightshift,
  60                                      unsigned long mask, unsigned int leftshift)
  61{
  62        return ((value >> rightshift) & mask) << leftshift;
  63}
  64
  65/*
  66 * Bits _PAGE_BIT_PRESENT, _PAGE_BIT_FILE and _PAGE_BIT_PROTNONE are taken,
  67 * split up the 29 bits of offset into this range.
  68 */
  69#define PTE_FILE_MAX_BITS       29
  70#define PTE_FILE_SHIFT1         (_PAGE_BIT_PRESENT + 1)
  71#define PTE_FILE_SHIFT2         (_PAGE_BIT_FILE + 1)
  72#define PTE_FILE_SHIFT3         (_PAGE_BIT_PROTNONE + 1)
  73#define PTE_FILE_BITS1          (PTE_FILE_SHIFT2 - PTE_FILE_SHIFT1 - 1)
  74#define PTE_FILE_BITS2          (PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1)
  75
  76#define PTE_FILE_MASK1          ((1U << PTE_FILE_BITS1) - 1)
  77#define PTE_FILE_MASK2          ((1U << PTE_FILE_BITS2) - 1)
  78
  79#define PTE_FILE_LSHIFT2        (PTE_FILE_BITS1)
  80#define PTE_FILE_LSHIFT3        (PTE_FILE_BITS1 + PTE_FILE_BITS2)
  81
  82static __always_inline pgoff_t pte_to_pgoff(pte_t pte)
  83{
  84        return (pgoff_t)
  85                (pte_bitop(pte.pte_low, PTE_FILE_SHIFT1, PTE_FILE_MASK1,  0)                +
  86                 pte_bitop(pte.pte_low, PTE_FILE_SHIFT2, PTE_FILE_MASK2,  PTE_FILE_LSHIFT2) +
  87                 pte_bitop(pte.pte_low, PTE_FILE_SHIFT3,           -1UL,  PTE_FILE_LSHIFT3));
  88}
  89
  90static __always_inline pte_t pgoff_to_pte(pgoff_t off)
  91{
  92        return (pte_t){
  93                .pte_low =
  94                        pte_bitop(off,                0, PTE_FILE_MASK1,  PTE_FILE_SHIFT1) +
  95                        pte_bitop(off, PTE_FILE_LSHIFT2, PTE_FILE_MASK2,  PTE_FILE_SHIFT2) +
  96                        pte_bitop(off, PTE_FILE_LSHIFT3,           -1UL,  PTE_FILE_SHIFT3) +
  97                        _PAGE_FILE,
  98        };
  99}
 100
 101/* Encode and de-code a swap entry */
 102#define SWP_TYPE_BITS (_PAGE_BIT_FILE - _PAGE_BIT_PRESENT - 1)
 103#define SWP_OFFSET_SHIFT (_PAGE_BIT_PROTNONE + 1)
 104
 105#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
 106
 107#define __swp_type(x)                   (((x).val >> (_PAGE_BIT_PRESENT + 1)) \
 108                                         & ((1U << SWP_TYPE_BITS) - 1))
 109#define __swp_offset(x)                 ((x).val >> SWP_OFFSET_SHIFT)
 110#define __swp_entry(type, offset)       ((swp_entry_t) { \
 111                                         ((type) << (_PAGE_BIT_PRESENT + 1)) \
 112                                         | ((offset) << SWP_OFFSET_SHIFT) })
 113#define __pte_to_swp_entry(pte)         ((swp_entry_t) { (pte).pte_low })
 114#define __swp_entry_to_pte(x)           ((pte_t) { .pte = (x).val })
 115
 116#endif /* _ASM_X86_PGTABLE_2LEVEL_H */
 117