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 */
get_pgd_slow(struct mm_struct * mm)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
free_pgd_slow(struct mm_struct * mm,pgd_t * pgd)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 }
106