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