| Catalin Marinas | 1355e2a | 2012-07-25 14:32:38 +0100 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/mm/hugetlbpage.c |
| 3 | * |
| 4 | * Copyright (C) 2012 ARM Ltd. |
| 5 | * |
| 6 | * Based on arch/x86/include/asm/hugetlb.h and Bill Carson's patches |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 20 | */ |
| 21 | |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/mm.h> |
| 25 | #include <linux/hugetlb.h> |
| 26 | #include <linux/pagemap.h> |
| 27 | #include <linux/err.h> |
| 28 | #include <linux/sysctl.h> |
| 29 | #include <asm/mman.h> |
| 30 | #include <asm/tlb.h> |
| 31 | #include <asm/tlbflush.h> |
| 32 | #include <asm/pgalloc.h> |
| 33 | |
| 34 | /* |
| 35 | * On ARM, huge pages are backed by pmd's rather than pte's, so we do a lot |
| 36 | * of type casting from pmd_t * to pte_t *. |
| 37 | */ |
| 38 | |
| 39 | pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) |
| 40 | { |
| 41 | pgd_t *pgd; |
| 42 | pud_t *pud; |
| 43 | pmd_t *pmd = NULL; |
| 44 | |
| 45 | pgd = pgd_offset(mm, addr); |
| 46 | if (pgd_present(*pgd)) { |
| 47 | pud = pud_offset(pgd, addr); |
| 48 | if (pud_present(*pud)) |
| 49 | pmd = pmd_offset(pud, addr); |
| 50 | } |
| 51 | |
| 52 | return (pte_t *)pmd; |
| 53 | } |
| 54 | |
| 55 | struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, |
| 56 | int write) |
| 57 | { |
| 58 | return ERR_PTR(-EINVAL); |
| 59 | } |
| 60 | |
| 61 | int pud_huge(pud_t pud) |
| 62 | { |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) |
| 67 | { |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | pte_t *huge_pte_alloc(struct mm_struct *mm, |
| 72 | unsigned long addr, unsigned long sz) |
| 73 | { |
| 74 | pgd_t *pgd; |
| 75 | pud_t *pud; |
| 76 | pte_t *pte = NULL; |
| 77 | |
| 78 | pgd = pgd_offset(mm, addr); |
| 79 | pud = pud_alloc(mm, pgd, addr); |
| 80 | if (pud) |
| 81 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
| 82 | |
| 83 | return pte; |
| 84 | } |
| 85 | |
| 86 | struct page * |
| 87 | follow_huge_pmd(struct mm_struct *mm, unsigned long address, |
| 88 | pmd_t *pmd, int write) |
| 89 | { |
| 90 | struct page *page; |
| 91 | |
| 92 | page = pte_page(*(pte_t *)pmd); |
| 93 | if (page) |
| 94 | page += ((address & ~PMD_MASK) >> PAGE_SHIFT); |
| 95 | return page; |
| 96 | } |
| 97 | |
| 98 | int pmd_huge(pmd_t pmd) |
| 99 | { |
| 100 | return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT); |
| 101 | } |