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 */ 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, 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 98 no_pte: 99 pmd_free(mm, new_pmd); 100 mm_dec_nr_pmds(mm); 101 no_pmd: 102 pud_free(mm, new_pud); 103 no_pud: 104 __pgd_free(new_pgd); 105 no_pgd: 106 return NULL; 107 } 108 109 void 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); 135 no_pmd: 136 pud_clear(pud); 137 pmd_free(mm, pmd); 138 mm_dec_nr_pmds(mm); 139 no_pud: 140 pgd_clear(pgd); 141 pud_free(mm, pud); 142 no_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 } 165