| 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, 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 | */ |
| 33 | pgd_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, new_pmd, 0); |
| 84 | if (!new_pte) |
| 85 | goto no_pte; |
| 86 | |
| 87 | #ifndef CONFIG_ARM_LPAE |
| 88 | /* |
| 89 | * Modify the PTE pointer to have the correct domain. This |
| 90 | * needs to be the vectors domain to avoid the low vectors |
| 91 | * being unmapped. |
| 92 | */ |
| 93 | pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK; |
| 94 | pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS); |
| 95 | #endif |
| 96 | |
| 97 | init_pud = pud_offset(init_pgd, 0); |
| 98 | init_pmd = pmd_offset(init_pud, 0); |
| 99 | init_pte = pte_offset_map(init_pmd, 0); |
| 100 | set_pte_ext(new_pte + 0, init_pte[0], 0); |
| 101 | set_pte_ext(new_pte + 1, init_pte[1], 0); |
| 102 | pte_unmap(init_pte); |
| 103 | pte_unmap(new_pte); |
| 104 | } |
| 105 | |
| 106 | return new_pgd; |
| 107 | |
| 108 | no_pte: |
| 109 | pmd_free(mm, new_pmd); |
| 110 | mm_dec_nr_pmds(mm); |
| 111 | no_pmd: |
| 112 | pud_free(mm, new_pud); |
| 113 | no_pud: |
| 114 | __pgd_free(new_pgd); |
| 115 | no_pgd: |
| 116 | return NULL; |
| 117 | } |
| 118 | |
| 119 | void pgd_free(struct mm_struct *mm, pgd_t *pgd_base) |
| 120 | { |
| 121 | pgd_t *pgd; |
| 122 | pud_t *pud; |
| 123 | pmd_t *pmd; |
| 124 | pgtable_t pte; |
| 125 | |
| 126 | if (!pgd_base) |
| 127 | return; |
| 128 | |
| 129 | pgd = pgd_base + pgd_index(0); |
| 130 | if (pgd_none_or_clear_bad(pgd)) |
| 131 | goto no_pgd; |
| 132 | |
| 133 | pud = pud_offset(pgd, 0); |
| 134 | if (pud_none_or_clear_bad(pud)) |
| 135 | goto no_pud; |
| 136 | |
| 137 | pmd = pmd_offset(pud, 0); |
| 138 | if (pmd_none_or_clear_bad(pmd)) |
| 139 | goto no_pmd; |
| 140 | |
| 141 | pte = pmd_pgtable(*pmd); |
| 142 | pmd_clear(pmd); |
| 143 | pte_free(mm, pte); |
| 144 | atomic_long_dec(&mm->nr_ptes); |
| 145 | no_pmd: |
| 146 | pud_clear(pud); |
| 147 | pmd_free(mm, pmd); |
| 148 | mm_dec_nr_pmds(mm); |
| 149 | no_pud: |
| 150 | pgd_clear(pgd); |
| 151 | pud_free(mm, pud); |
| 152 | no_pgd: |
| 153 | #ifdef CONFIG_ARM_LPAE |
| 154 | /* |
| 155 | * Free modules/pkmap or identity pmd tables. |
| 156 | */ |
| 157 | for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) { |
| 158 | if (pgd_none_or_clear_bad(pgd)) |
| 159 | continue; |
| 160 | if (pgd_val(*pgd) & L_PGD_SWAPPER) |
| 161 | continue; |
| 162 | pud = pud_offset(pgd, 0); |
| 163 | if (pud_none_or_clear_bad(pud)) |
| 164 | continue; |
| 165 | pmd = pmd_offset(pud, 0); |
| 166 | pud_clear(pud); |
| 167 | pmd_free(mm, pmd); |
| 168 | mm_dec_nr_pmds(mm); |
| 169 | pgd_clear(pgd); |
| 170 | pud_free(mm, pud); |
| 171 | } |
| 172 | #endif |
| 173 | __pgd_free(pgd_base); |
| 174 | } |