2 * IBM System z Huge TLB Page Support for Kernel.
4 * Copyright IBM Corp. 2007
5 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
9 #include <linux/hugetlb.h>
12 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
13 pte_t *pteptr, pte_t pteval)
15 pmd_t *pmdp = (pmd_t *) pteptr;
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;
25 pmd_val(*pmdp) = pte_val(pteval);
28 int arch_prepare_hugepage(struct page *page)
30 unsigned long addr = page_to_phys(page);
35 if (MACHINE_HAS_HPAGE)
38 ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
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;
47 page[1].index = (unsigned long) ptep;
51 void arch_release_hugepage(struct page *page)
55 if (MACHINE_HAS_HPAGE)
58 ptep = (pte_t *) page[1].index;
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);
67 pte_t *huge_pte_alloc(struct mm_struct *mm,
68 unsigned long addr, unsigned long sz)
74 pgdp = pgd_offset(mm, addr);
75 pudp = pud_alloc(mm, pgdp, addr);
77 pmdp = pmd_alloc(mm, pudp, addr);
78 return (pte_t *) pmdp;
81 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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);
93 return (pte_t *) pmdp;
96 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
101 struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
104 return ERR_PTR(-EINVAL);
107 int pmd_huge(pmd_t pmd)
109 if (!MACHINE_HAS_HPAGE)
112 return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
115 int pud_huge(pud_t pud)
120 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
121 pmd_t *pmdp, int write)
125 if (!MACHINE_HAS_HPAGE)
128 page = pmd_page(*pmdp);
130 page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);