Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6-microblaze.git] / arch / unicore32 / mm / pgd.c
1 /*
2  * linux/arch/unicore32/mm/pgd.c
3  *
4  * Code specific to PKUnity SoC and UniCore ISA
5  *
6  * Copyright (C) 2001-2010 GUAN Xue-tao
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 #include <linux/mm.h>
13 #include <linux/gfp.h>
14 #include <linux/highmem.h>
15
16 #include <asm/pgalloc.h>
17 #include <asm/page.h>
18 #include <asm/tlbflush.h>
19
20 #include "mm.h"
21
22 #define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
23
24 /*
25  * need to get a 4k page for level 1
26  */
27 pgd_t *get_pgd_slow(struct mm_struct *mm)
28 {
29         pgd_t *new_pgd, *init_pgd;
30         pmd_t *new_pmd, *init_pmd;
31         pte_t *new_pte, *init_pte;
32
33         new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 0);
34         if (!new_pgd)
35                 goto no_pgd;
36
37         memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
38
39         /*
40          * Copy over the kernel and IO PGD entries
41          */
42         init_pgd = pgd_offset_k(0);
43         memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
44                        (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
45
46         clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
47
48         if (!vectors_high()) {
49                 /*
50                  * On UniCore, first page must always be allocated since it
51                  * contains the machine vectors.
52                  */
53                 new_pmd = pmd_alloc(mm, (pud_t *)new_pgd, 0);
54                 if (!new_pmd)
55                         goto no_pmd;
56
57                 new_pte = pte_alloc_map(mm, new_pmd, 0);
58                 if (!new_pte)
59                         goto no_pte;
60
61                 init_pmd = pmd_offset((pud_t *)init_pgd, 0);
62                 init_pte = pte_offset_map(init_pmd, 0);
63                 set_pte(new_pte, *init_pte);
64                 pte_unmap(init_pte);
65                 pte_unmap(new_pte);
66         }
67
68         return new_pgd;
69
70 no_pte:
71         pmd_free(mm, new_pmd);
72         mm_dec_nr_pmds(mm);
73 no_pmd:
74         free_pages((unsigned long)new_pgd, 0);
75 no_pgd:
76         return NULL;
77 }
78
79 void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
80 {
81         pmd_t *pmd;
82         pgtable_t pte;
83
84         if (!pgd)
85                 return;
86
87         /* pgd is always present and good */
88         pmd = pmd_off(pgd, 0);
89         if (pmd_none(*pmd))
90                 goto free;
91         if (pmd_bad(*pmd)) {
92                 pmd_ERROR(*pmd);
93                 pmd_clear(pmd);
94                 goto free;
95         }
96
97         pte = pmd_pgtable(*pmd);
98         pmd_clear(pmd);
99         pte_free(mm, pte);
100         atomic_long_dec(&mm->nr_ptes);
101         pmd_free(mm, pmd);
102         mm_dec_nr_pmds(mm);
103 free:
104         free_pages((unsigned long) pgd, 0);
105 }