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 12 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 13 pte_t *pteptr, pte_t pteval) 14 { 15 pmd_t *pmdp = (pmd_t *) pteptr; 16 unsigned long mask; 17 18 if (!MACHINE_HAS_HPAGE) { 19 pteptr = (pte_t *) pte_page(pteval)[1].index; 20 mask = pte_val(pteval) & 21 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO); 22 pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask; 23 } 24 25 pmd_val(*pmdp) = pte_val(pteval); 26 } 27 28 int arch_prepare_hugepage(struct page *page) 29 { 30 unsigned long addr = page_to_phys(page); 31 pte_t pte; 32 pte_t *ptep; 33 int i; 34 35 if (MACHINE_HAS_HPAGE) 36 return 0; 37 38 ptep = (pte_t *) pte_alloc_one(&init_mm, addr); 39 if (!ptep) 40 return -ENOMEM; 41 42 pte = mk_pte(page, PAGE_RW); 43 for (i = 0; i < PTRS_PER_PTE; i++) { 44 set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte); 45 pte_val(pte) += PAGE_SIZE; 46 } 47 page[1].index = (unsigned long) ptep; 48 return 0; 49 } 50 51 void arch_release_hugepage(struct page *page) 52 { 53 pte_t *ptep; 54 55 if (MACHINE_HAS_HPAGE) 56 return; 57 58 ptep = (pte_t *) page[1].index; 59 if (!ptep) 60 return; 61 clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY, 62 PTRS_PER_PTE * sizeof(pte_t)); 63 page_table_free(&init_mm, (unsigned long *) ptep); 64 page[1].index = 0; 65 } 66 67 pte_t *huge_pte_alloc(struct mm_struct *mm, 68 unsigned long addr, unsigned long sz) 69 { 70 pgd_t *pgdp; 71 pud_t *pudp; 72 pmd_t *pmdp = NULL; 73 74 pgdp = pgd_offset(mm, addr); 75 pudp = pud_alloc(mm, pgdp, addr); 76 if (pudp) 77 pmdp = pmd_alloc(mm, pudp, addr); 78 return (pte_t *) pmdp; 79 } 80 81 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 82 { 83 pgd_t *pgdp; 84 pud_t *pudp; 85 pmd_t *pmdp = NULL; 86 87 pgdp = pgd_offset(mm, addr); 88 if (pgd_present(*pgdp)) { 89 pudp = pud_offset(pgdp, addr); 90 if (pud_present(*pudp)) 91 pmdp = pmd_offset(pudp, addr); 92 } 93 return (pte_t *) pmdp; 94 } 95 96 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 97 { 98 return 0; 99 } 100 101 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, 102 int write) 103 { 104 return ERR_PTR(-EINVAL); 105 } 106 107 int pmd_huge(pmd_t pmd) 108 { 109 if (!MACHINE_HAS_HPAGE) 110 return 0; 111 112 return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE); 113 } 114 115 int pud_huge(pud_t pud) 116 { 117 return 0; 118 } 119 120 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, 121 pmd_t *pmdp, int write) 122 { 123 struct page *page; 124 125 if (!MACHINE_HAS_HPAGE) 126 return NULL; 127 128 page = pmd_page(*pmdp); 129 if (page) 130 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT); 131 return page; 132 } 133