Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * linux/arch/arm/mm/pgd.c
3 *
4 * Copyright (C) 1998-2005 Russell King
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.
9 */
10#include <linux/mm.h>
11#include <linux/gfp.h>
12#include <linux/highmem.h>
13#include <linux/slab.h>
14
15#include <asm/cp15.h>
16#include <asm/pgalloc.h>
17#include <asm/page.h>
18#include <asm/tlbflush.h>
19
20#include "mm.h"
21
22#ifdef CONFIG_ARM_LPAE
23#define __pgd_alloc() kmalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL)
24#define __pgd_free(pgd) kfree(pgd)
25#else
26#define __pgd_alloc() (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_REPEAT, 2)
27#define __pgd_free(pgd) free_pages((unsigned long)pgd, 2)
28#endif
29
30/*
31 * need to get a 16k page for level 1
32 */
33pgd_t *pgd_alloc(struct mm_struct *mm)
34{
35 pgd_t *new_pgd, *init_pgd;
36 pud_t *new_pud, *init_pud;
37 pmd_t *new_pmd, *init_pmd;
38 pte_t *new_pte, *init_pte;
39
40 new_pgd = __pgd_alloc();
41 if (!new_pgd)
42 goto no_pgd;
43
44 memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
45
46 /*
47 * Copy over the kernel and IO PGD entries
48 */
49 init_pgd = pgd_offset_k(0);
50 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
51 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
52
53 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
54
55#ifdef CONFIG_ARM_LPAE
56 /*
57 * Allocate PMD table for modules and pkmap mappings.
58 */
59 new_pud = pud_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
60 MODULES_VADDR);
61 if (!new_pud)
62 goto no_pud;
63
64 new_pmd = pmd_alloc(mm, new_pud, 0);
65 if (!new_pmd)
66 goto no_pmd;
67#endif
68
69 if (!vectors_high()) {
70 /*
71 * On ARM, first page must always be allocated since it
72 * contains the machine vectors. The vectors are always high
73 * with LPAE.
74 */
75 new_pud = pud_alloc(mm, new_pgd, 0);
76 if (!new_pud)
77 goto no_pud;
78
79 new_pmd = pmd_alloc(mm, new_pud, 0);
80 if (!new_pmd)
81 goto no_pmd;
82
83 new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
84 if (!new_pte)
85 goto no_pte;
86
87 init_pud = pud_offset(init_pgd, 0);
88 init_pmd = pmd_offset(init_pud, 0);
89 init_pte = pte_offset_map(init_pmd, 0);
90 set_pte_ext(new_pte + 0, init_pte[0], 0);
91 set_pte_ext(new_pte + 1, init_pte[1], 0);
92 pte_unmap(init_pte);
93 pte_unmap(new_pte);
94 }
95
96 return new_pgd;
97
98no_pte:
99 pmd_free(mm, new_pmd);
100 mm_dec_nr_pmds(mm);
101no_pmd:
102 pud_free(mm, new_pud);
103no_pud:
104 __pgd_free(new_pgd);
105no_pgd:
106 return NULL;
107}
108
109void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
110{
111 pgd_t *pgd;
112 pud_t *pud;
113 pmd_t *pmd;
114 pgtable_t pte;
115
116 if (!pgd_base)
117 return;
118
119 pgd = pgd_base + pgd_index(0);
120 if (pgd_none_or_clear_bad(pgd))
121 goto no_pgd;
122
123 pud = pud_offset(pgd, 0);
124 if (pud_none_or_clear_bad(pud))
125 goto no_pud;
126
127 pmd = pmd_offset(pud, 0);
128 if (pmd_none_or_clear_bad(pmd))
129 goto no_pmd;
130
131 pte = pmd_pgtable(*pmd);
132 pmd_clear(pmd);
133 pte_free(mm, pte);
134 atomic_long_dec(&mm->nr_ptes);
135no_pmd:
136 pud_clear(pud);
137 pmd_free(mm, pmd);
138 mm_dec_nr_pmds(mm);
139no_pud:
140 pgd_clear(pgd);
141 pud_free(mm, pud);
142no_pgd:
143#ifdef CONFIG_ARM_LPAE
144 /*
145 * Free modules/pkmap or identity pmd tables.
146 */
147 for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
148 if (pgd_none_or_clear_bad(pgd))
149 continue;
150 if (pgd_val(*pgd) & L_PGD_SWAPPER)
151 continue;
152 pud = pud_offset(pgd, 0);
153 if (pud_none_or_clear_bad(pud))
154 continue;
155 pmd = pmd_offset(pud, 0);
156 pud_clear(pud);
157 pmd_free(mm, pmd);
158 mm_dec_nr_pmds(mm);
159 pgd_clear(pgd);
160 pud_free(mm, pud);
161 }
162#endif
163 __pgd_free(pgd_base);
164}