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  */
  14 static inline void native_set_pte(pte_t *ptep , pte_t pte)
  15 {
  16         *ptep = pte;
  17 }
  18
  19 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
  20 {
  21         *pmdp = pmd;
  22 }
  23
  24 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
  25 {
  26         native_set_pte(ptep, pte);
  27 }
  28
  29 static inline void native_pmd_clear(pmd_t *pmdp)
  30 {
  31         native_set_pmd(pmdp, __pmd(0));
  32 }
  33
  34 static 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
  41 static 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
  50 static 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 */
  59 static 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
  82 static __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
  90 static __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 */