Commit | Line | Data |
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1da177e4 | 1 | /* |
0c668984 | 2 | * linux/arch/arm/mm/pgd.c |
1da177e4 | 3 | * |
90072059 | 4 | * Copyright (C) 1998-2005 Russell King |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
1da177e4 | 9 | */ |
1da177e4 | 10 | #include <linux/mm.h> |
1da177e4 | 11 | #include <linux/highmem.h> |
1da177e4 LT |
12 | |
13 | #include <asm/pgalloc.h> | |
14 | #include <asm/page.h> | |
1da177e4 LT |
15 | #include <asm/tlbflush.h> |
16 | ||
1b2e2b73 RK |
17 | #include "mm.h" |
18 | ||
1da177e4 LT |
19 | #define FIRST_KERNEL_PGD_NR (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD) |
20 | ||
21 | /* | |
22 | * need to get a 16k page for level 1 | |
23 | */ | |
24 | pgd_t *get_pgd_slow(struct mm_struct *mm) | |
25 | { | |
26 | pgd_t *new_pgd, *init_pgd; | |
27 | pmd_t *new_pmd, *init_pmd; | |
28 | pte_t *new_pte, *init_pte; | |
29 | ||
30 | new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2); | |
31 | if (!new_pgd) | |
32 | goto no_pgd; | |
33 | ||
34 | memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t)); | |
35 | ||
a343e607 RK |
36 | /* |
37 | * Copy over the kernel and IO PGD entries | |
38 | */ | |
1da177e4 | 39 | init_pgd = pgd_offset_k(0); |
a343e607 RK |
40 | memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR, |
41 | (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t)); | |
42 | ||
43 | clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t)); | |
1da177e4 LT |
44 | |
45 | if (!vectors_high()) { | |
1da177e4 LT |
46 | /* |
47 | * On ARM, first page must always be allocated since it | |
48 | * contains the machine vectors. | |
49 | */ | |
50 | new_pmd = pmd_alloc(mm, new_pgd, 0); | |
51 | if (!new_pmd) | |
52 | goto no_pmd; | |
53 | ||
54 | new_pte = pte_alloc_map(mm, new_pmd, 0); | |
55 | if (!new_pte) | |
56 | goto no_pte; | |
57 | ||
58 | init_pmd = pmd_offset(init_pgd, 0); | |
59 | init_pte = pte_offset_map_nested(init_pmd, 0); | |
60 | set_pte(new_pte, *init_pte); | |
61 | pte_unmap_nested(init_pte); | |
62 | pte_unmap(new_pte); | |
1da177e4 LT |
63 | } |
64 | ||
1da177e4 LT |
65 | return new_pgd; |
66 | ||
67 | no_pte: | |
1da177e4 | 68 | pmd_free(new_pmd); |
1da177e4 | 69 | no_pmd: |
1da177e4 | 70 | free_pages((unsigned long)new_pgd, 2); |
1da177e4 LT |
71 | no_pgd: |
72 | return NULL; | |
73 | } | |
74 | ||
75 | void free_pgd_slow(pgd_t *pgd) | |
76 | { | |
77 | pmd_t *pmd; | |
78 | struct page *pte; | |
79 | ||
80 | if (!pgd) | |
81 | return; | |
82 | ||
83 | /* pgd is always present and good */ | |
155bb144 | 84 | pmd = pmd_off(pgd, 0); |
1da177e4 LT |
85 | if (pmd_none(*pmd)) |
86 | goto free; | |
87 | if (pmd_bad(*pmd)) { | |
88 | pmd_ERROR(*pmd); | |
89 | pmd_clear(pmd); | |
90 | goto free; | |
91 | } | |
92 | ||
93 | pte = pmd_page(*pmd); | |
94 | pmd_clear(pmd); | |
df849a15 | 95 | dec_zone_page_state(virt_to_page((unsigned long *)pgd), NR_PAGETABLE); |
4c21e2f2 | 96 | pte_lock_deinit(pte); |
1da177e4 LT |
97 | pte_free(pte); |
98 | pmd_free(pmd); | |
99 | free: | |
100 | free_pages((unsigned long) pgd, 2); | |
101 | } |