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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Hibernation support specific for i386 - temporary page tables
4 *
5 * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
6 */
7
8#include <linux/gfp.h>
9#include <linux/suspend.h>
10#include <linux/memblock.h>
11#include <linux/pgtable.h>
12
13#include <asm/page.h>
14#include <asm/mmzone.h>
15#include <asm/sections.h>
16#include <asm/suspend.h>
17
18/* Pointer to the temporary resume page tables */
19pgd_t *resume_pg_dir;
20
21/* The following three functions are based on the analogous code in
22 * arch/x86/mm/init_32.c
23 */
24
25/*
26 * Create a middle page table on a resume-safe page and put a pointer to it in
27 * the given global directory entry. This only returns the gd entry
28 * in non-PAE compilation mode, since the middle layer is folded.
29 */
30static pmd_t *resume_one_md_table_init(pgd_t *pgd)
31{
32 p4d_t *p4d;
33 pud_t *pud;
34 pmd_t *pmd_table;
35
36#ifdef CONFIG_X86_PAE
37 pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
38 if (!pmd_table)
39 return NULL;
40
41 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
42 p4d = p4d_offset(pgd, 0);
43 pud = pud_offset(p4d, 0);
44
45 BUG_ON(pmd_table != pmd_offset(pud, 0));
46#else
47 p4d = p4d_offset(pgd, 0);
48 pud = pud_offset(p4d, 0);
49 pmd_table = pmd_offset(pud, 0);
50#endif
51
52 return pmd_table;
53}
54
55/*
56 * Create a page table on a resume-safe page and place a pointer to it in
57 * a middle page directory entry.
58 */
59static pte_t *resume_one_page_table_init(pmd_t *pmd)
60{
61 if (pmd_none(*pmd)) {
62 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
63 if (!page_table)
64 return NULL;
65
66 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
67
68 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
69
70 return page_table;
71 }
72
73 return pte_offset_kernel(pmd, 0);
74}
75
76/*
77 * This maps the physical memory to kernel virtual address space, a total
78 * of max_low_pfn pages, by creating page tables starting from address
79 * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
80 */
81static int resume_physical_mapping_init(pgd_t *pgd_base)
82{
83 unsigned long pfn;
84 pgd_t *pgd;
85 pmd_t *pmd;
86 pte_t *pte;
87 int pgd_idx, pmd_idx;
88
89 pgd_idx = pgd_index(PAGE_OFFSET);
90 pgd = pgd_base + pgd_idx;
91 pfn = 0;
92
93 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
94 pmd = resume_one_md_table_init(pgd);
95 if (!pmd)
96 return -ENOMEM;
97
98 if (pfn >= max_low_pfn)
99 continue;
100
101 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
102 if (pfn >= max_low_pfn)
103 break;
104
105 /* Map with big pages if possible, otherwise create
106 * normal page tables.
107 * NOTE: We can mark everything as executable here
108 */
109 if (boot_cpu_has(X86_FEATURE_PSE)) {
110 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
111 pfn += PTRS_PER_PTE;
112 } else {
113 pte_t *max_pte;
114
115 pte = resume_one_page_table_init(pmd);
116 if (!pte)
117 return -ENOMEM;
118
119 max_pte = pte + PTRS_PER_PTE;
120 for (; pte < max_pte; pte++, pfn++) {
121 if (pfn >= max_low_pfn)
122 break;
123
124 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
125 }
126 }
127 }
128 }
129
130 return 0;
131}
132
133static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
134{
135#ifdef CONFIG_X86_PAE
136 int i;
137
138 /* Init entries of the first-level page table to the zero page */
139 for (i = 0; i < PTRS_PER_PGD; i++)
140 set_pgd(pg_dir + i,
141 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
142#endif
143}
144
145static int set_up_temporary_text_mapping(pgd_t *pgd_base)
146{
147 pgd_t *pgd;
148 pmd_t *pmd;
149 pte_t *pte;
150
151 pgd = pgd_base + pgd_index(restore_jump_address);
152
153 pmd = resume_one_md_table_init(pgd);
154 if (!pmd)
155 return -ENOMEM;
156
157 if (boot_cpu_has(X86_FEATURE_PSE)) {
158 set_pmd(pmd + pmd_index(restore_jump_address),
159 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(PAGE_KERNEL_LARGE_EXEC)));
160 } else {
161 pte = resume_one_page_table_init(pmd);
162 if (!pte)
163 return -ENOMEM;
164 set_pte(pte + pte_index(restore_jump_address),
165 __pte((jump_address_phys & PAGE_MASK) | pgprot_val(PAGE_KERNEL_EXEC)));
166 }
167
168 return 0;
169}
170
171asmlinkage int swsusp_arch_resume(void)
172{
173 int error;
174
175 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
176 if (!resume_pg_dir)
177 return -ENOMEM;
178
179 resume_init_first_level_page_table(resume_pg_dir);
180
181 error = set_up_temporary_text_mapping(resume_pg_dir);
182 if (error)
183 return error;
184
185 error = resume_physical_mapping_init(resume_pg_dir);
186 if (error)
187 return error;
188
189 temp_pgt = __pa(resume_pg_dir);
190
191 error = relocate_restore_code();
192 if (error)
193 return error;
194
195 /* We have got enough memory and from now on we cannot recover */
196 restore_image();
197 return 0;
198}
1/*
2 * Hibernation support specific for i386 - temporary page tables
3 *
4 * Distribute under GPLv2
5 *
6 * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
7 */
8
9#include <linux/gfp.h>
10#include <linux/suspend.h>
11#include <linux/bootmem.h>
12
13#include <asm/page.h>
14#include <asm/pgtable.h>
15#include <asm/mmzone.h>
16#include <asm/sections.h>
17
18/* Defined in hibernate_asm_32.S */
19extern int restore_image(void);
20
21/* Pointer to the temporary resume page tables */
22pgd_t *resume_pg_dir;
23
24/* The following three functions are based on the analogous code in
25 * arch/x86/mm/init_32.c
26 */
27
28/*
29 * Create a middle page table on a resume-safe page and put a pointer to it in
30 * the given global directory entry. This only returns the gd entry
31 * in non-PAE compilation mode, since the middle layer is folded.
32 */
33static pmd_t *resume_one_md_table_init(pgd_t *pgd)
34{
35 p4d_t *p4d;
36 pud_t *pud;
37 pmd_t *pmd_table;
38
39#ifdef CONFIG_X86_PAE
40 pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
41 if (!pmd_table)
42 return NULL;
43
44 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
45 p4d = p4d_offset(pgd, 0);
46 pud = pud_offset(p4d, 0);
47
48 BUG_ON(pmd_table != pmd_offset(pud, 0));
49#else
50 p4d = p4d_offset(pgd, 0);
51 pud = pud_offset(p4d, 0);
52 pmd_table = pmd_offset(pud, 0);
53#endif
54
55 return pmd_table;
56}
57
58/*
59 * Create a page table on a resume-safe page and place a pointer to it in
60 * a middle page directory entry.
61 */
62static pte_t *resume_one_page_table_init(pmd_t *pmd)
63{
64 if (pmd_none(*pmd)) {
65 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
66 if (!page_table)
67 return NULL;
68
69 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
70
71 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
72
73 return page_table;
74 }
75
76 return pte_offset_kernel(pmd, 0);
77}
78
79/*
80 * This maps the physical memory to kernel virtual address space, a total
81 * of max_low_pfn pages, by creating page tables starting from address
82 * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
83 */
84static int resume_physical_mapping_init(pgd_t *pgd_base)
85{
86 unsigned long pfn;
87 pgd_t *pgd;
88 pmd_t *pmd;
89 pte_t *pte;
90 int pgd_idx, pmd_idx;
91
92 pgd_idx = pgd_index(PAGE_OFFSET);
93 pgd = pgd_base + pgd_idx;
94 pfn = 0;
95
96 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
97 pmd = resume_one_md_table_init(pgd);
98 if (!pmd)
99 return -ENOMEM;
100
101 if (pfn >= max_low_pfn)
102 continue;
103
104 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
105 if (pfn >= max_low_pfn)
106 break;
107
108 /* Map with big pages if possible, otherwise create
109 * normal page tables.
110 * NOTE: We can mark everything as executable here
111 */
112 if (boot_cpu_has(X86_FEATURE_PSE)) {
113 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
114 pfn += PTRS_PER_PTE;
115 } else {
116 pte_t *max_pte;
117
118 pte = resume_one_page_table_init(pmd);
119 if (!pte)
120 return -ENOMEM;
121
122 max_pte = pte + PTRS_PER_PTE;
123 for (; pte < max_pte; pte++, pfn++) {
124 if (pfn >= max_low_pfn)
125 break;
126
127 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
128 }
129 }
130 }
131 }
132
133 return 0;
134}
135
136static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
137{
138#ifdef CONFIG_X86_PAE
139 int i;
140
141 /* Init entries of the first-level page table to the zero page */
142 for (i = 0; i < PTRS_PER_PGD; i++)
143 set_pgd(pg_dir + i,
144 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
145#endif
146}
147
148asmlinkage int swsusp_arch_resume(void)
149{
150 int error;
151
152 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
153 if (!resume_pg_dir)
154 return -ENOMEM;
155
156 resume_init_first_level_page_table(resume_pg_dir);
157 error = resume_physical_mapping_init(resume_pg_dir);
158 if (error)
159 return error;
160
161 /* We have got enough memory and from now on we cannot recover */
162 restore_image();
163 return 0;
164}
165
166/*
167 * pfn_is_nosave - check if given pfn is in the 'nosave' section
168 */
169
170int pfn_is_nosave(unsigned long pfn)
171{
172 unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
173 unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
174 return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
175}