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(mm) kmalloc_array(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL | __GFP_ZERO)
21 #define _pgd_free(mm, pgd) kfree(pgd)
22 #else
23 #define _pgd_alloc(mm) __pgd_alloc(mm, 2)
24 #define _pgd_free(mm, pgd) __pgd_free(mm, pgd)
25 #endif
26
27 /*
28 * need to get a 16k page for level 1
29 */
pgd_alloc(struct mm_struct * mm)30 pgd_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(mm);
39 if (!new_pgd)
40 goto no_pgd;
41
42 /*
43 * Copy over the kernel and IO PGD entries
44 */
45 init_pgd = pgd_offset_k(0);
46 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
47 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
48
49 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
50
51 #ifdef CONFIG_ARM_LPAE
52 /*
53 * Allocate PMD table for modules and pkmap mappings.
54 */
55 new_p4d = p4d_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
56 MODULES_VADDR);
57 if (!new_p4d)
58 goto no_p4d;
59
60 new_pud = pud_alloc(mm, new_p4d, 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 #ifdef CONFIG_KASAN
68 /*
69 * Copy PMD table for KASAN shadow mappings.
70 */
71 init_pgd = pgd_offset_k(TASK_SIZE);
72 init_p4d = p4d_offset(init_pgd, TASK_SIZE);
73 init_pud = pud_offset(init_p4d, TASK_SIZE);
74 init_pmd = pmd_offset(init_pud, TASK_SIZE);
75 new_pmd = pmd_offset(new_pud, TASK_SIZE);
76 memcpy(new_pmd, init_pmd,
77 (pmd_index(MODULES_VADDR) - pmd_index(TASK_SIZE))
78 * sizeof(pmd_t));
79 clean_dcache_area(new_pmd, PTRS_PER_PMD * sizeof(pmd_t));
80 #endif /* CONFIG_KASAN */
81 #endif /* CONFIG_LPAE */
82
83 if (!vectors_high()) {
84 /*
85 * On ARM, first page must always be allocated since it
86 * contains the machine vectors. The vectors are always high
87 * with LPAE.
88 */
89 new_p4d = p4d_alloc(mm, new_pgd, 0);
90 if (!new_p4d)
91 goto no_p4d;
92
93 new_pud = pud_alloc(mm, new_p4d, 0);
94 if (!new_pud)
95 goto no_pud;
96
97 new_pmd = pmd_alloc(mm, new_pud, 0);
98 if (!new_pmd)
99 goto no_pmd;
100
101 new_pte = pte_alloc_map(mm, new_pmd, 0);
102 if (!new_pte)
103 goto no_pte;
104
105 #ifndef CONFIG_ARM_LPAE
106 /*
107 * Modify the PTE pointer to have the correct domain. This
108 * needs to be the vectors domain to avoid the low vectors
109 * being unmapped.
110 */
111 pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
112 pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
113 #endif
114
115 init_p4d = p4d_offset(init_pgd, 0);
116 init_pud = pud_offset(init_p4d, 0);
117 init_pmd = pmd_offset(init_pud, 0);
118 init_pte = pte_offset_map(init_pmd, 0);
119 set_pte_ext(new_pte + 0, init_pte[0], 0);
120 set_pte_ext(new_pte + 1, init_pte[1], 0);
121 pte_unmap(init_pte);
122 pte_unmap(new_pte);
123 }
124
125 return new_pgd;
126
127 no_pte:
128 pmd_free(mm, new_pmd);
129 mm_dec_nr_pmds(mm);
130 no_pmd:
131 pud_free(mm, new_pud);
132 no_pud:
133 p4d_free(mm, new_p4d);
134 no_p4d:
135 _pgd_free(mm, new_pgd);
136 no_pgd:
137 return NULL;
138 }
139
pgd_free(struct mm_struct * mm,pgd_t * pgd_base)140 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
141 {
142 pgd_t *pgd;
143 p4d_t *p4d;
144 pud_t *pud;
145 pmd_t *pmd;
146 pgtable_t pte;
147
148 if (!pgd_base)
149 return;
150
151 pgd = pgd_base + pgd_index(0);
152 if (pgd_none_or_clear_bad(pgd))
153 goto no_pgd;
154
155 p4d = p4d_offset(pgd, 0);
156 if (p4d_none_or_clear_bad(p4d))
157 goto no_p4d;
158
159 pud = pud_offset(p4d, 0);
160 if (pud_none_or_clear_bad(pud))
161 goto no_pud;
162
163 pmd = pmd_offset(pud, 0);
164 if (pmd_none_or_clear_bad(pmd))
165 goto no_pmd;
166
167 pte = pmd_pgtable(*pmd);
168 pmd_clear(pmd);
169 pte_free(mm, pte);
170 mm_dec_nr_ptes(mm);
171 no_pmd:
172 pud_clear(pud);
173 pmd_free(mm, pmd);
174 mm_dec_nr_pmds(mm);
175 no_pud:
176 p4d_clear(p4d);
177 pud_free(mm, pud);
178 no_p4d:
179 pgd_clear(pgd);
180 p4d_free(mm, p4d);
181 no_pgd:
182 #ifdef CONFIG_ARM_LPAE
183 /*
184 * Free modules/pkmap or identity pmd tables.
185 */
186 for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
187 if (pgd_none_or_clear_bad(pgd))
188 continue;
189 if (pgd_val(*pgd) & L_PGD_SWAPPER)
190 continue;
191 p4d = p4d_offset(pgd, 0);
192 if (p4d_none_or_clear_bad(p4d))
193 continue;
194 pud = pud_offset(p4d, 0);
195 if (pud_none_or_clear_bad(pud))
196 continue;
197 pmd = pmd_offset(pud, 0);
198 pud_clear(pud);
199 pmd_free(mm, pmd);
200 mm_dec_nr_pmds(mm);
201 p4d_clear(p4d);
202 pud_free(mm, pud);
203 mm_dec_nr_puds(mm);
204 pgd_clear(pgd);
205 p4d_free(mm, p4d);
206 }
207 #endif
208 _pgd_free(mm, pgd_base);
209 }
210