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 */ 30pgd_t *pgd_alloc(struct mm_struct *mm) 31{ 32 pgd_t *new_pgd, *init_pgd; 33 p4d_t *new_p4d, *init_p4d; 34 pud_t *new_pud, *init_pud; 35 pmd_t *new_pmd, *init_pmd; 36 pte_t *new_pte, *init_pte; 37 38 new_pgd = __pgd_alloc(); 39 if (!new_pgd) 40 goto no_pgd; 41 42 memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 43 44 /* 45 * Copy over the kernel and IO PGD entries 46 */ 47 init_pgd = pgd_offset_k(0); 48 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD, 49 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 50 51 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t)); 52 53#ifdef CONFIG_ARM_LPAE 54 /* 55 * Allocate PMD table for modules and pkmap mappings. 56 */ 57 new_p4d = p4d_alloc(mm, new_pgd + pgd_index(MODULES_VADDR), 58 MODULES_VADDR); 59 if (!new_p4d) 60 goto no_p4d; 61 62 new_pud = pud_alloc(mm, new_p4d, MODULES_VADDR); 63 if (!new_pud) 64 goto no_pud; 65 66 new_pmd = pmd_alloc(mm, new_pud, 0); 67 if (!new_pmd) 68 goto no_pmd; 69#ifdef CONFIG_KASAN 70 /* 71 * Copy PMD table for KASAN shadow mappings. 72 */ 73 init_pgd = pgd_offset_k(TASK_SIZE); 74 init_p4d = p4d_offset(init_pgd, TASK_SIZE); 75 init_pud = pud_offset(init_p4d, TASK_SIZE); 76 init_pmd = pmd_offset(init_pud, TASK_SIZE); 77 new_pmd = pmd_offset(new_pud, TASK_SIZE); 78 memcpy(new_pmd, init_pmd, 79 (pmd_index(MODULES_VADDR) - pmd_index(TASK_SIZE)) 80 * sizeof(pmd_t)); 81 clean_dcache_area(new_pmd, PTRS_PER_PMD * sizeof(pmd_t)); 82#endif /* CONFIG_KASAN */ 83#endif /* CONFIG_LPAE */ 84 85 if (!vectors_high()) { 86 /* 87 * On ARM, first page must always be allocated since it 88 * contains the machine vectors. The vectors are always high 89 * with LPAE. 90 */ 91 new_p4d = p4d_alloc(mm, new_pgd, 0); 92 if (!new_p4d) 93 goto no_p4d; 94 95 new_pud = pud_alloc(mm, new_p4d, 0); 96 if (!new_pud) 97 goto no_pud; 98 99 new_pmd = pmd_alloc(mm, new_pud, 0); 100 if (!new_pmd) 101 goto no_pmd; 102 103 new_pte = pte_alloc_map(mm, new_pmd, 0); 104 if (!new_pte) 105 goto no_pte; 106 107#ifndef CONFIG_ARM_LPAE 108 /* 109 * Modify the PTE pointer to have the correct domain. This 110 * needs to be the vectors domain to avoid the low vectors 111 * being unmapped. 112 */ 113 pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK; 114 pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS); 115#endif 116 117 init_p4d = p4d_offset(init_pgd, 0); 118 init_pud = pud_offset(init_p4d, 0); 119 init_pmd = pmd_offset(init_pud, 0); 120 init_pte = pte_offset_map(init_pmd, 0); 121 set_pte_ext(new_pte + 0, init_pte[0], 0); 122 set_pte_ext(new_pte + 1, init_pte[1], 0); 123 pte_unmap(init_pte); 124 pte_unmap(new_pte); 125 } 126 127 return new_pgd; 128 129no_pte: 130 pmd_free(mm, new_pmd); 131 mm_dec_nr_pmds(mm); 132no_pmd: 133 pud_free(mm, new_pud); 134no_pud: 135 p4d_free(mm, new_p4d); 136no_p4d: 137 __pgd_free(new_pgd); 138no_pgd: 139 return NULL; 140} 141 142void pgd_free(struct mm_struct *mm, pgd_t *pgd_base) 143{ 144 pgd_t *pgd; 145 p4d_t *p4d; 146 pud_t *pud; 147 pmd_t *pmd; 148 pgtable_t pte; 149 150 if (!pgd_base) 151 return; 152 153 pgd = pgd_base + pgd_index(0); 154 if (pgd_none_or_clear_bad(pgd)) 155 goto no_pgd; 156 157 p4d = p4d_offset(pgd, 0); 158 if (p4d_none_or_clear_bad(p4d)) 159 goto no_p4d; 160 161 pud = pud_offset(p4d, 0); 162 if (pud_none_or_clear_bad(pud)) 163 goto no_pud; 164 165 pmd = pmd_offset(pud, 0); 166 if (pmd_none_or_clear_bad(pmd)) 167 goto no_pmd; 168 169 pte = pmd_pgtable(*pmd); 170 pmd_clear(pmd); 171 pte_free(mm, pte); 172 mm_dec_nr_ptes(mm); 173no_pmd: 174 pud_clear(pud); 175 pmd_free(mm, pmd); 176 mm_dec_nr_pmds(mm); 177no_pud: 178 p4d_clear(p4d); 179 pud_free(mm, pud); 180no_p4d: 181 pgd_clear(pgd); 182 p4d_free(mm, p4d); 183no_pgd: 184#ifdef CONFIG_ARM_LPAE 185 /* 186 * Free modules/pkmap or identity pmd tables. 187 */ 188 for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) { 189 if (pgd_none_or_clear_bad(pgd)) 190 continue; 191 if (pgd_val(*pgd) & L_PGD_SWAPPER) 192 continue; 193 p4d = p4d_offset(pgd, 0); 194 if (p4d_none_or_clear_bad(p4d)) 195 continue; 196 pud = pud_offset(p4d, 0); 197 if (pud_none_or_clear_bad(pud)) 198 continue; 199 pmd = pmd_offset(pud, 0); 200 pud_clear(pud); 201 pmd_free(mm, pmd); 202 mm_dec_nr_pmds(mm); 203 p4d_clear(p4d); 204 pud_free(mm, pud); 205 mm_dec_nr_puds(mm); 206 pgd_clear(pgd); 207 p4d_free(mm, p4d); 208 } 209#endif 210 __pgd_free(pgd_base); 211} 212