ARM: 7090/1: CACHE-L2X0: filter start address can be 0 and is often 0
[linux-3.10.git] / arch / arm / mm / pgd.c
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
14 #include <asm/pgalloc.h>
15 #include <asm/page.h>
16 #include <asm/tlbflush.h>
17
18 #include "mm.h"
19
20 /*
21  * need to get a 16k page for level 1
22  */
23 pgd_t *pgd_alloc(struct mm_struct *mm)
24 {
25         pgd_t *new_pgd, *init_pgd;
26         pud_t *new_pud, *init_pud;
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         memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
35
36         /*
37          * Copy over the kernel and IO PGD entries
38          */
39         init_pgd = pgd_offset_k(0);
40         memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
41                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
42
43         clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
44
45         if (!vectors_high()) {
46                 /*
47                  * On ARM, first page must always be allocated since it
48                  * contains the machine vectors.
49                  */
50                 new_pud = pud_alloc(mm, new_pgd, 0);
51                 if (!new_pud)
52                         goto no_pud;
53
54                 new_pmd = pmd_alloc(mm, new_pud, 0);
55                 if (!new_pmd)
56                         goto no_pmd;
57
58                 new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
59                 if (!new_pte)
60                         goto no_pte;
61
62                 init_pud = pud_offset(init_pgd, 0);
63                 init_pmd = pmd_offset(init_pud, 0);
64                 init_pte = pte_offset_map(init_pmd, 0);
65                 set_pte_ext(new_pte, *init_pte, 0);
66                 pte_unmap(init_pte);
67                 pte_unmap(new_pte);
68         }
69
70         return new_pgd;
71
72 no_pte:
73         pmd_free(mm, new_pmd);
74 no_pmd:
75         pud_free(mm, new_pud);
76 no_pud:
77         free_pages((unsigned long)new_pgd, 2);
78 no_pgd:
79         return NULL;
80 }
81
82 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
83 {
84         pgd_t *pgd;
85         pud_t *pud;
86         pmd_t *pmd;
87         pgtable_t pte;
88
89         if (!pgd_base)
90                 return;
91
92         pgd = pgd_base + pgd_index(0);
93         if (pgd_none_or_clear_bad(pgd))
94                 goto no_pgd;
95
96         pud = pud_offset(pgd, 0);
97         if (pud_none_or_clear_bad(pud))
98                 goto no_pud;
99
100         pmd = pmd_offset(pud, 0);
101         if (pmd_none_or_clear_bad(pmd))
102                 goto no_pmd;
103
104         pte = pmd_pgtable(*pmd);
105         pmd_clear(pmd);
106         pte_free(mm, pte);
107 no_pmd:
108         pud_clear(pud);
109         pmd_free(mm, pmd);
110 no_pud:
111         pgd_clear(pgd);
112         pud_free(mm, pud);
113 no_pgd:
114         free_pages((unsigned long) pgd_base, 2);
115 }