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1355e2a6 CM |
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 | } |