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 */
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();
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
129 no_pte:
130 pmd_free(mm, new_pmd);
131 mm_dec_nr_pmds(mm);
132 no_pmd:
133 pud_free(mm, new_pud);
134 no_pud:
135 p4d_free(mm, new_p4d);
136 no_p4d:
137 __pgd_free(new_pgd);
138 no_pgd:
139 return NULL;
140 }
141
pgd_free(struct mm_struct * mm,pgd_t * pgd_base)142 void 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);
173 no_pmd:
174 pud_clear(pud);
175 pmd_free(mm, pmd);
176 mm_dec_nr_pmds(mm);
177 no_pud:
178 p4d_clear(p4d);
179 pud_free(mm, pud);
180 no_p4d:
181 pgd_clear(pgd);
182 p4d_free(mm, p4d);
183 no_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