summaryrefslogtreecommitdiff
path: root/arch/arm/mm/pgd.c
blob: f8e9bc58a84f08729a9261ca2e50ee78c51c6834 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/mm/pgd.c
 *
 *  Copyright (C) 1998-2005 Russell King
 */
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/slab.h>

#include <asm/cp15.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/tlbflush.h>

#include "mm.h"

#ifdef CONFIG_ARM_LPAE
#define __pgd_alloc()	kmalloc_array(PTRS_PER_PGD, sizeof(pgd_t), GFP_KERNEL)
#define __pgd_free(pgd)	kfree(pgd)
#else
#define __pgd_alloc()	(pgd_t *)__get_free_pages(GFP_KERNEL, 2)
#define __pgd_free(pgd)	free_pages((unsigned long)pgd, 2)
#endif

/*
 * need to get a 16k page for level 1
 */
pgd_t *pgd_alloc(struct mm_struct *mm)
{
	pgd_t *new_pgd, *init_pgd;
	p4d_t *new_p4d, *init_p4d;
	pud_t *new_pud, *init_pud;
	pmd_t *new_pmd, *init_pmd;
	pte_t *new_pte, *init_pte;

	new_pgd = __pgd_alloc();
	if (!new_pgd)
		goto no_pgd;

	memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));

	/*
	 * Copy over the kernel and IO PGD entries
	 */
	init_pgd = pgd_offset_k(0);
	memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));

	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));

#ifdef CONFIG_ARM_LPAE
	/*
	 * Allocate PMD table for modules and pkmap mappings.
	 */
	new_p4d = p4d_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
			    MODULES_VADDR);
	if (!new_p4d)
		goto no_p4d;

	new_pud = pud_alloc(mm, new_p4d, MODULES_VADDR);
	if (!new_pud)
		goto no_pud;

	new_pmd = pmd_alloc(mm, new_pud, 0);
	if (!new_pmd)
		goto no_pmd;
#ifdef CONFIG_KASAN
	/*
	 * Copy PMD table for KASAN shadow mappings.
	 */
	init_pgd = pgd_offset_k(TASK_SIZE);
	init_p4d = p4d_offset(init_pgd, TASK_SIZE);
	init_pud = pud_offset(init_p4d, TASK_SIZE);
	init_pmd = pmd_offset(init_pud, TASK_SIZE);
	new_pmd = pmd_offset(new_pud, TASK_SIZE);
	memcpy(new_pmd, init_pmd,
	       (pmd_index(MODULES_VADDR) - pmd_index(TASK_SIZE))
	       * sizeof(pmd_t));
	clean_dcache_area(new_pmd, PTRS_PER_PMD * sizeof(pmd_t));
#endif /* CONFIG_KASAN */
#endif /* CONFIG_LPAE */

	if (!vectors_high()) {
		/*
		 * On ARM, first page must always be allocated since it
		 * contains the machine vectors. The vectors are always high
		 * with LPAE.
		 */
		new_p4d = p4d_alloc(mm, new_pgd, 0);
		if (!new_p4d)
			goto no_p4d;

		new_pud = pud_alloc(mm, new_p4d, 0);
		if (!new_pud)
			goto no_pud;

		new_pmd = pmd_alloc(mm, new_pud, 0);
		if (!new_pmd)
			goto no_pmd;

		new_pte = pte_alloc_map(mm, new_pmd, 0);
		if (!new_pte)
			goto no_pte;

#ifndef CONFIG_ARM_LPAE
		/*
		 * Modify the PTE pointer to have the correct domain.  This
		 * needs to be the vectors domain to avoid the low vectors
		 * being unmapped.
		 */
		pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
		pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
#endif

		init_p4d = p4d_offset(init_pgd, 0);
		init_pud = pud_offset(init_p4d, 0);
		init_pmd = pmd_offset(init_pud, 0);
		init_pte = pte_offset_map(init_pmd, 0);
		set_pte_ext(new_pte + 0, init_pte[0], 0);
		set_pte_ext(new_pte + 1, init_pte[1], 0);
		pte_unmap(init_pte);
		pte_unmap(new_pte);
	}

	return new_pgd;

no_pte:
	pmd_free(mm, new_pmd);
	mm_dec_nr_pmds(mm);
no_pmd:
	pud_free(mm, new_pud);
no_pud:
	p4d_free(mm, new_p4d);
no_p4d:
	__pgd_free(new_pgd);
no_pgd:
	return NULL;
}

void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
{
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pgtable_t pte;

	if (!pgd_base)
		return;

	pgd = pgd_base + pgd_index(0);
	if (pgd_none_or_clear_bad(pgd))
		goto no_pgd;

	p4d = p4d_offset(pgd, 0);
	if (p4d_none_or_clear_bad(p4d))
		goto no_p4d;

	pud = pud_offset(p4d, 0);
	if (pud_none_or_clear_bad(pud))
		goto no_pud;

	pmd = pmd_offset(pud, 0);
	if (pmd_none_or_clear_bad(pmd))
		goto no_pmd;

	pte = pmd_pgtable(*pmd);
	pmd_clear(pmd);
	pte_free(mm, pte);
	mm_dec_nr_ptes(mm);
no_pmd:
	pud_clear(pud);
	pmd_free(mm, pmd);
	mm_dec_nr_pmds(mm);
no_pud:
	p4d_clear(p4d);
	pud_free(mm, pud);
no_p4d:
	pgd_clear(pgd);
	p4d_free(mm, p4d);
no_pgd:
#ifdef CONFIG_ARM_LPAE
	/*
	 * Free modules/pkmap or identity pmd tables.
	 */
	for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
		if (pgd_none_or_clear_bad(pgd))
			continue;
		if (pgd_val(*pgd) & L_PGD_SWAPPER)
			continue;
		p4d = p4d_offset(pgd, 0);
		if (p4d_none_or_clear_bad(p4d))
			continue;
		pud = pud_offset(p4d, 0);
		if (pud_none_or_clear_bad(pud))
			continue;
		pmd = pmd_offset(pud, 0);
		pud_clear(pud);
		pmd_free(mm, pmd);
		mm_dec_nr_pmds(mm);
		p4d_clear(p4d);
		pud_free(mm, pud);
		mm_dec_nr_puds(mm);
		pgd_clear(pgd);
		p4d_free(mm, p4d);
	}
#endif
	__pgd_free(pgd_base);
}