arch/s390/mm/hugetlbpage.c

   1 /*
   2  *  IBM System z Huge TLB Page Support for Kernel.
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   6  */
   7
   8 #include <linux/mm.h>
   9 #include <linux/hugetlb.h>
  10
  11 static inline pmd_t __pte_to_pmd(pte_t pte)
  12 {
  13         pmd_t pmd;
  14
  15         /*
  16          * Convert encoding               pte bits         pmd bits
  17          *                              lIR.uswrdy.p    dy..R...I...wr
  18          * empty                        010.000000.0 -> 00..0...1...00
  19          * prot-none, clean, old        111.000000.1 -> 00..1...1...00
  20          * prot-none, clean, young      111.000001.1 -> 01..1...1...00
  21          * prot-none, dirty, old        111.000010.1 -> 10..1...1...00
  22          * prot-none, dirty, young      111.000011.1 -> 11..1...1...00
  23          * read-only, clean, old        111.000100.1 -> 00..1...1...01
  24          * read-only, clean, young      101.000101.1 -> 01..1...0...01
  25          * read-only, dirty, old        111.000110.1 -> 10..1...1...01
  26          * read-only, dirty, young      101.000111.1 -> 11..1...0...01
  27          * read-write, clean, old       111.001100.1 -> 00..1...1...11
  28          * read-write, clean, young     101.001101.1 -> 01..1...0...11
  29          * read-write, dirty, old       110.001110.1 -> 10..0...1...11
  30          * read-write, dirty, young     100.001111.1 -> 11..0...0...11
  31          * HW-bits: R read-only, I invalid
  32          * SW-bits: p present, y young, d dirty, r read, w write, s special,
  33          *          u unused, l large
  34          */
  35         if (pte_present(pte)) {
  36                 pmd_val(pmd) = pte_val(pte) & PAGE_MASK;
  37                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_READ) >> 4;
  38                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_WRITE) >> 4;
  39                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_INVALID) >> 5;
  40                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_PROTECT);
  41                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_DIRTY) << 10;
  42                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_YOUNG) << 10;
  43                 pmd_val(pmd) |= (pte_val(pte) & _PAGE_SOFT_DIRTY) << 13;
  44         } else
  45                 pmd_val(pmd) = _SEGMENT_ENTRY_INVALID;
  46         return pmd;
  47 }
  48
  49 static inline pte_t __pmd_to_pte(pmd_t pmd)
  50 {
  51         pte_t pte;
  52
  53         /*
  54          * Convert encoding                pmd bits         pte bits
  55          *                              dy..R...I...wr    lIR.uswrdy.p
  56          * empty                        00..0...1...00 -> 010.000000.0
  57          * prot-none, clean, old        00..1...1...00 -> 111.000000.1
  58          * prot-none, clean, young      01..1...1...00 -> 111.000001.1
  59          * prot-none, dirty, old        10..1...1...00 -> 111.000010.1
  60          * prot-none, dirty, young      11..1...1...00 -> 111.000011.1
  61          * read-only, clean, old        00..1...1...01 -> 111.000100.1
  62          * read-only, clean, young      01..1...0...01 -> 101.000101.1
  63          * read-only, dirty, old        10..1...1...01 -> 111.000110.1
  64          * read-only, dirty, young      11..1...0...01 -> 101.000111.1
  65          * read-write, clean, old       00..1...1...11 -> 111.001100.1
  66          * read-write, clean, young     01..1...0...11 -> 101.001101.1
  67          * read-write, dirty, old       10..0...1...11 -> 110.001110.1
  68          * read-write, dirty, young     11..0...0...11 -> 100.001111.1
  69          * HW-bits: R read-only, I invalid
  70          * SW-bits: p present, y young, d dirty, r read, w write, s special,
  71          *          u unused, l large
  72          */
  73         if (pmd_present(pmd)) {
  74                 pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE;
  75                 pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
  76                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_READ) << 4;
  77                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) << 4;
  78                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) << 5;
  79                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT);
  80                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY) >> 10;
  81                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG) >> 10;
  82                 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_SOFT_DIRTY) >> 13;
  83         } else
  84                 pte_val(pte) = _PAGE_INVALID;
  85         return pte;
  86 }
  87
  88 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
  89                      pte_t *ptep, pte_t pte)
  90 {
  91         pmd_t pmd = __pte_to_pmd(pte);
  92
  93         pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE;
  94         *(pmd_t *) ptep = pmd;
  95 }
  96
  97 pte_t huge_ptep_get(pte_t *ptep)
  98 {
  99         pmd_t pmd = *(pmd_t *) ptep;
 100
 101         return __pmd_to_pte(pmd);
 102 }
 103
 104 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 105                               unsigned long addr, pte_t *ptep)
 106 {
 107         pmd_t *pmdp = (pmd_t *) ptep;
 108         pmd_t old;
 109
 110         old = pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
 111         return __pmd_to_pte(old);
 112 }
 113
 114 pte_t *huge_pte_alloc(struct mm_struct *mm,
 115                         unsigned long addr, unsigned long sz)
 116 {
 117         pgd_t *pgdp;
 118         pud_t *pudp;
 119         pmd_t *pmdp = NULL;
 120
 121         pgdp = pgd_offset(mm, addr);
 122         pudp = pud_alloc(mm, pgdp, addr);
 123         if (pudp)
 124                 pmdp = pmd_alloc(mm, pudp, addr);
 125         return (pte_t *) pmdp;
 126 }
 127
 128 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 129 {
 130         pgd_t *pgdp;
 131         pud_t *pudp;
 132         pmd_t *pmdp = NULL;
 133
 134         pgdp = pgd_offset(mm, addr);
 135         if (pgd_present(*pgdp)) {
 136                 pudp = pud_offset(pgdp, addr);
 137                 if (pud_present(*pudp))
 138                         pmdp = pmd_offset(pudp, addr);
 139         }
 140         return (pte_t *) pmdp;
 141 }
 142
 143 int pmd_huge(pmd_t pmd)
 144 {
 145         return pmd_large(pmd);
 146 }
 147
 148 int pud_huge(pud_t pud)
 149 {
 150         return 0;
 151 }