1*53492b1dSGerald Schaefer /* 2*53492b1dSGerald Schaefer * IBM System z Huge TLB Page Support for Kernel. 3*53492b1dSGerald Schaefer * 4*53492b1dSGerald Schaefer * Copyright 2007 IBM Corp. 5*53492b1dSGerald Schaefer * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com> 6*53492b1dSGerald Schaefer */ 7*53492b1dSGerald Schaefer 8*53492b1dSGerald Schaefer #include <linux/mm.h> 9*53492b1dSGerald Schaefer #include <linux/hugetlb.h> 10*53492b1dSGerald Schaefer 11*53492b1dSGerald Schaefer 12*53492b1dSGerald Schaefer void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, 13*53492b1dSGerald Schaefer pte_t *pteptr, pte_t pteval) 14*53492b1dSGerald Schaefer { 15*53492b1dSGerald Schaefer pmd_t *pmdp = (pmd_t *) pteptr; 16*53492b1dSGerald Schaefer pte_t shadow_pteval = pteval; 17*53492b1dSGerald Schaefer unsigned long mask; 18*53492b1dSGerald Schaefer 19*53492b1dSGerald Schaefer if (!MACHINE_HAS_HPAGE) { 20*53492b1dSGerald Schaefer pteptr = (pte_t *) pte_page(pteval)[1].index; 21*53492b1dSGerald Schaefer mask = pte_val(pteval) & 22*53492b1dSGerald Schaefer (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO); 23*53492b1dSGerald Schaefer pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask; 24*53492b1dSGerald Schaefer if (mm->context.noexec) { 25*53492b1dSGerald Schaefer pteptr += PTRS_PER_PTE; 26*53492b1dSGerald Schaefer pte_val(shadow_pteval) = 27*53492b1dSGerald Schaefer (_SEGMENT_ENTRY + __pa(pteptr)) | mask; 28*53492b1dSGerald Schaefer } 29*53492b1dSGerald Schaefer } 30*53492b1dSGerald Schaefer 31*53492b1dSGerald Schaefer pmd_val(*pmdp) = pte_val(pteval); 32*53492b1dSGerald Schaefer if (mm->context.noexec) { 33*53492b1dSGerald Schaefer pmdp = get_shadow_table(pmdp); 34*53492b1dSGerald Schaefer pmd_val(*pmdp) = pte_val(shadow_pteval); 35*53492b1dSGerald Schaefer } 36*53492b1dSGerald Schaefer } 37*53492b1dSGerald Schaefer 38*53492b1dSGerald Schaefer int arch_prepare_hugepage(struct page *page) 39*53492b1dSGerald Schaefer { 40*53492b1dSGerald Schaefer unsigned long addr = page_to_phys(page); 41*53492b1dSGerald Schaefer pte_t pte; 42*53492b1dSGerald Schaefer pte_t *ptep; 43*53492b1dSGerald Schaefer int i; 44*53492b1dSGerald Schaefer 45*53492b1dSGerald Schaefer if (MACHINE_HAS_HPAGE) 46*53492b1dSGerald Schaefer return 0; 47*53492b1dSGerald Schaefer 48*53492b1dSGerald Schaefer ptep = (pte_t *) pte_alloc_one(&init_mm, address); 49*53492b1dSGerald Schaefer if (!ptep) 50*53492b1dSGerald Schaefer return -ENOMEM; 51*53492b1dSGerald Schaefer 52*53492b1dSGerald Schaefer pte = mk_pte(page, PAGE_RW); 53*53492b1dSGerald Schaefer for (i = 0; i < PTRS_PER_PTE; i++) { 54*53492b1dSGerald Schaefer set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte); 55*53492b1dSGerald Schaefer pte_val(pte) += PAGE_SIZE; 56*53492b1dSGerald Schaefer } 57*53492b1dSGerald Schaefer page[1].index = (unsigned long) ptep; 58*53492b1dSGerald Schaefer return 0; 59*53492b1dSGerald Schaefer } 60*53492b1dSGerald Schaefer 61*53492b1dSGerald Schaefer void arch_release_hugepage(struct page *page) 62*53492b1dSGerald Schaefer { 63*53492b1dSGerald Schaefer pte_t *ptep; 64*53492b1dSGerald Schaefer 65*53492b1dSGerald Schaefer if (MACHINE_HAS_HPAGE) 66*53492b1dSGerald Schaefer return; 67*53492b1dSGerald Schaefer 68*53492b1dSGerald Schaefer ptep = (pte_t *) page[1].index; 69*53492b1dSGerald Schaefer if (!ptep) 70*53492b1dSGerald Schaefer return; 71*53492b1dSGerald Schaefer pte_free(&init_mm, ptep); 72*53492b1dSGerald Schaefer page[1].index = 0; 73*53492b1dSGerald Schaefer } 74*53492b1dSGerald Schaefer 75*53492b1dSGerald Schaefer pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr) 76*53492b1dSGerald Schaefer { 77*53492b1dSGerald Schaefer pgd_t *pgdp; 78*53492b1dSGerald Schaefer pud_t *pudp; 79*53492b1dSGerald Schaefer pmd_t *pmdp = NULL; 80*53492b1dSGerald Schaefer 81*53492b1dSGerald Schaefer pgdp = pgd_offset(mm, addr); 82*53492b1dSGerald Schaefer pudp = pud_alloc(mm, pgdp, addr); 83*53492b1dSGerald Schaefer if (pudp) 84*53492b1dSGerald Schaefer pmdp = pmd_alloc(mm, pudp, addr); 85*53492b1dSGerald Schaefer return (pte_t *) pmdp; 86*53492b1dSGerald Schaefer } 87*53492b1dSGerald Schaefer 88*53492b1dSGerald Schaefer pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 89*53492b1dSGerald Schaefer { 90*53492b1dSGerald Schaefer pgd_t *pgdp; 91*53492b1dSGerald Schaefer pud_t *pudp; 92*53492b1dSGerald Schaefer pmd_t *pmdp = NULL; 93*53492b1dSGerald Schaefer 94*53492b1dSGerald Schaefer pgdp = pgd_offset(mm, addr); 95*53492b1dSGerald Schaefer if (pgd_present(*pgdp)) { 96*53492b1dSGerald Schaefer pudp = pud_offset(pgdp, addr); 97*53492b1dSGerald Schaefer if (pud_present(*pudp)) 98*53492b1dSGerald Schaefer pmdp = pmd_offset(pudp, addr); 99*53492b1dSGerald Schaefer } 100*53492b1dSGerald Schaefer return (pte_t *) pmdp; 101*53492b1dSGerald Schaefer } 102*53492b1dSGerald Schaefer 103*53492b1dSGerald Schaefer int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 104*53492b1dSGerald Schaefer { 105*53492b1dSGerald Schaefer return 0; 106*53492b1dSGerald Schaefer } 107*53492b1dSGerald Schaefer 108*53492b1dSGerald Schaefer struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, 109*53492b1dSGerald Schaefer int write) 110*53492b1dSGerald Schaefer { 111*53492b1dSGerald Schaefer return ERR_PTR(-EINVAL); 112*53492b1dSGerald Schaefer } 113*53492b1dSGerald Schaefer 114*53492b1dSGerald Schaefer int pmd_huge(pmd_t pmd) 115*53492b1dSGerald Schaefer { 116*53492b1dSGerald Schaefer if (!MACHINE_HAS_HPAGE) 117*53492b1dSGerald Schaefer return 0; 118*53492b1dSGerald Schaefer 119*53492b1dSGerald Schaefer return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE); 120*53492b1dSGerald Schaefer } 121*53492b1dSGerald Schaefer 122*53492b1dSGerald Schaefer struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, 123*53492b1dSGerald Schaefer pmd_t *pmdp, int write) 124*53492b1dSGerald Schaefer { 125*53492b1dSGerald Schaefer struct page *page; 126*53492b1dSGerald Schaefer 127*53492b1dSGerald Schaefer if (!MACHINE_HAS_HPAGE) 128*53492b1dSGerald Schaefer return NULL; 129*53492b1dSGerald Schaefer 130*53492b1dSGerald Schaefer page = pmd_page(*pmdp); 131*53492b1dSGerald Schaefer if (page) 132*53492b1dSGerald Schaefer page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT); 133*53492b1dSGerald Schaefer return page; 134*53492b1dSGerald Schaefer } 135