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 } else 44 pmd_val(pmd) = _SEGMENT_ENTRY_INVALID; 45 return pmd; 46 } 47 48 static inline pte_t __pmd_to_pte(pmd_t pmd) 49 { 50 pte_t pte; 51 52 /* 53 * Convert encoding pmd bits pte bits 54 * dy..R...I...wr lIR.uswrdy.p 55 * empty 00..0...1...00 -> 010.000000.0 56 * prot-none, clean, old 00..1...1...00 -> 111.000000.1 57 * prot-none, clean, young 01..1...1...00 -> 111.000001.1 58 * prot-none, dirty, old 10..1...1...00 -> 111.000010.1 59 * prot-none, dirty, young 11..1...1...00 -> 111.000011.1 60 * read-only, clean, old 00..1...1...01 -> 111.000100.1 61 * read-only, clean, young 01..1...0...01 -> 101.000101.1 62 * read-only, dirty, old 10..1...1...01 -> 111.000110.1 63 * read-only, dirty, young 11..1...0...01 -> 101.000111.1 64 * read-write, clean, old 00..1...1...11 -> 111.001100.1 65 * read-write, clean, young 01..1...0...11 -> 101.001101.1 66 * read-write, dirty, old 10..0...1...11 -> 110.001110.1 67 * read-write, dirty, young 11..0...0...11 -> 100.001111.1 68 * HW-bits: R read-only, I invalid 69 * SW-bits: p present, y young, d dirty, r read, w write, s special, 70 * u unused, l large 71 */ 72 if (pmd_present(pmd)) { 73 pte_val(pte) = pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN_LARGE; 74 pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT; 75 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_READ) << 4; 76 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) << 4; 77 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_INVALID) << 5; 78 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_PROTECT); 79 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY) >> 10; 80 pte_val(pte) |= (pmd_val(pmd) & _SEGMENT_ENTRY_YOUNG) >> 10; 81 } else 82 pte_val(pte) = _PAGE_INVALID; 83 return pte; 84 } 85 86 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 87 pte_t *ptep, pte_t pte) 88 { 89 pmd_t pmd = __pte_to_pmd(pte); 90 91 pmd_val(pmd) |= _SEGMENT_ENTRY_LARGE; 92 *(pmd_t *) ptep = pmd; 93 } 94 95 pte_t huge_ptep_get(pte_t *ptep) 96 { 97 pmd_t pmd = *(pmd_t *) ptep; 98 99 return __pmd_to_pte(pmd); 100 } 101 102 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, 103 unsigned long addr, pte_t *ptep) 104 { 105 pmd_t *pmdp = (pmd_t *) ptep; 106 pte_t pte = huge_ptep_get(ptep); 107 108 pmdp_flush_direct(mm, addr, pmdp); 109 pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY; 110 return pte; 111 } 112 113 pte_t *huge_pte_alloc(struct mm_struct *mm, 114 unsigned long addr, unsigned long sz) 115 { 116 pgd_t *pgdp; 117 pud_t *pudp; 118 pmd_t *pmdp = NULL; 119 120 pgdp = pgd_offset(mm, addr); 121 pudp = pud_alloc(mm, pgdp, addr); 122 if (pudp) 123 pmdp = pmd_alloc(mm, pudp, addr); 124 return (pte_t *) pmdp; 125 } 126 127 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 128 { 129 pgd_t *pgdp; 130 pud_t *pudp; 131 pmd_t *pmdp = NULL; 132 133 pgdp = pgd_offset(mm, addr); 134 if (pgd_present(*pgdp)) { 135 pudp = pud_offset(pgdp, addr); 136 if (pud_present(*pudp)) 137 pmdp = pmd_offset(pudp, addr); 138 } 139 return (pte_t *) pmdp; 140 } 141 142 int pmd_huge(pmd_t pmd) 143 { 144 return pmd_large(pmd); 145 } 146 147 int pud_huge(pud_t pud) 148 { 149 return 0; 150 } 151