1 /* 2 * IBM System z Huge TLB Page Support for Kernel. 3 * 4 * Copyright 2007 IBM Corp. 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 page_table_free(&init_mm, (unsigned long *) ptep); 62 page[1].index = 0; 63 } 64 65 pte_t *huge_pte_alloc(struct mm_struct *mm, 66 unsigned long addr, unsigned long sz) 67 { 68 pgd_t *pgdp; 69 pud_t *pudp; 70 pmd_t *pmdp = NULL; 71 72 pgdp = pgd_offset(mm, addr); 73 pudp = pud_alloc(mm, pgdp, addr); 74 if (pudp) 75 pmdp = pmd_alloc(mm, pudp, addr); 76 return (pte_t *) pmdp; 77 } 78 79 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 80 { 81 pgd_t *pgdp; 82 pud_t *pudp; 83 pmd_t *pmdp = NULL; 84 85 pgdp = pgd_offset(mm, addr); 86 if (pgd_present(*pgdp)) { 87 pudp = pud_offset(pgdp, addr); 88 if (pud_present(*pudp)) 89 pmdp = pmd_offset(pudp, addr); 90 } 91 return (pte_t *) pmdp; 92 } 93 94 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 95 { 96 return 0; 97 } 98 99 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, 100 int write) 101 { 102 return ERR_PTR(-EINVAL); 103 } 104 105 int pmd_huge(pmd_t pmd) 106 { 107 if (!MACHINE_HAS_HPAGE) 108 return 0; 109 110 return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE); 111 } 112 113 int pud_huge(pud_t pud) 114 { 115 return 0; 116 } 117 118 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, 119 pmd_t *pmdp, int write) 120 { 121 struct page *page; 122 123 if (!MACHINE_HAS_HPAGE) 124 return NULL; 125 126 page = pmd_page(*pmdp); 127 if (page) 128 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT); 129 return page; 130 } 131