1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/arch/arm/mm/pgd.c 4 * 5 * Copyright (C) 1998-2005 Russell King 6 */ 7 #include <linux/mm.h> 8 #include <linux/gfp.h> 9 #include <linux/highmem.h> 10 #include <linux/slab.h> 11 12 #include <asm/cp15.h> 13 #include <asm/pgalloc.h> 14 #include <asm/page.h> 15 #include <asm/tlbflush.h> 16 17 #include "mm.h" 18 19 #ifdef CONFIG_ARM_LPAE 20 #define __pgd_alloc() kmalloc_array(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL) 21 #define __pgd_free(pgd) kfree(pgd) 22 #else 23 #define __pgd_alloc() (pgd_t *)__get_free_pages(GFP_KERNEL, 2) 24 #define __pgd_free(pgd) free_pages((unsigned long)pgd, 2) 25 #endif 26 27 /* 28 * need to get a 16k page for level 1 29 */ 30 pgd_t *pgd_alloc(struct mm_struct *mm) 31 { 32 pgd_t *new_pgd, *init_pgd; 33 pud_t *new_pud, *init_pud; 34 pmd_t *new_pmd, *init_pmd; 35 pte_t *new_pte, *init_pte; 36 37 new_pgd = __pgd_alloc(); 38 if (!new_pgd) 39 goto no_pgd; 40 41 memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 42 43 /* 44 * Copy over the kernel and IO PGD entries 45 */ 46 init_pgd = pgd_offset_k(0); 47 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD, 48 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 49 50 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t)); 51 52 #ifdef CONFIG_ARM_LPAE 53 /* 54 * Allocate PMD table for modules and pkmap mappings. 55 */ 56 new_pud = pud_alloc(mm, new_pgd + pgd_index(MODULES_VADDR), 57 MODULES_VADDR); 58 if (!new_pud) 59 goto no_pud; 60 61 new_pmd = pmd_alloc(mm, new_pud, 0); 62 if (!new_pmd) 63 goto no_pmd; 64 #endif 65 66 if (!vectors_high()) { 67 /* 68 * On ARM, first page must always be allocated since it 69 * contains the machine vectors. The vectors are always high 70 * with LPAE. 71 */ 72 new_pud = pud_alloc(mm, new_pgd, 0); 73 if (!new_pud) 74 goto no_pud; 75 76 new_pmd = pmd_alloc(mm, new_pud, 0); 77 if (!new_pmd) 78 goto no_pmd; 79 80 new_pte = pte_alloc_map(mm, new_pmd, 0); 81 if (!new_pte) 82 goto no_pte; 83 84 #ifndef CONFIG_ARM_LPAE 85 /* 86 * Modify the PTE pointer to have the correct domain. This 87 * needs to be the vectors domain to avoid the low vectors 88 * being unmapped. 89 */ 90 pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK; 91 pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS); 92 #endif 93 94 init_pud = pud_offset(init_pgd, 0); 95 init_pmd = pmd_offset(init_pud, 0); 96 init_pte = pte_offset_map(init_pmd, 0); 97 set_pte_ext(new_pte + 0, init_pte[0], 0); 98 set_pte_ext(new_pte + 1, init_pte[1], 0); 99 pte_unmap(init_pte); 100 pte_unmap(new_pte); 101 } 102 103 return new_pgd; 104 105 no_pte: 106 pmd_free(mm, new_pmd); 107 mm_dec_nr_pmds(mm); 108 no_pmd: 109 pud_free(mm, new_pud); 110 no_pud: 111 __pgd_free(new_pgd); 112 no_pgd: 113 return NULL; 114 } 115 116 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base) 117 { 118 pgd_t *pgd; 119 pud_t *pud; 120 pmd_t *pmd; 121 pgtable_t pte; 122 123 if (!pgd_base) 124 return; 125 126 pgd = pgd_base + pgd_index(0); 127 if (pgd_none_or_clear_bad(pgd)) 128 goto no_pgd; 129 130 pud = pud_offset(pgd, 0); 131 if (pud_none_or_clear_bad(pud)) 132 goto no_pud; 133 134 pmd = pmd_offset(pud, 0); 135 if (pmd_none_or_clear_bad(pmd)) 136 goto no_pmd; 137 138 pte = pmd_pgtable(*pmd); 139 pmd_clear(pmd); 140 pte_free(mm, pte); 141 mm_dec_nr_ptes(mm); 142 no_pmd: 143 pud_clear(pud); 144 pmd_free(mm, pmd); 145 mm_dec_nr_pmds(mm); 146 no_pud: 147 pgd_clear(pgd); 148 pud_free(mm, pud); 149 no_pgd: 150 #ifdef CONFIG_ARM_LPAE 151 /* 152 * Free modules/pkmap or identity pmd tables. 153 */ 154 for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) { 155 if (pgd_none_or_clear_bad(pgd)) 156 continue; 157 if (pgd_val(*pgd) & L_PGD_SWAPPER) 158 continue; 159 pud = pud_offset(pgd, 0); 160 if (pud_none_or_clear_bad(pud)) 161 continue; 162 pmd = pmd_offset(pud, 0); 163 pud_clear(pud); 164 pmd_free(mm, pmd); 165 mm_dec_nr_pmds(mm); 166 pgd_clear(pgd); 167 pud_free(mm, pud); 168 } 169 #endif 170 __pgd_free(pgd_base); 171 } 172