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-rw-r--r--arch/i386/power/suspend.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/arch/i386/power/suspend.c b/arch/i386/power/suspend.c
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index 000000000000..db5e98d2eb73
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+++ b/arch/i386/power/suspend.c
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1/*
2 * Suspend 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
16/* Defined in arch/i386/power/swsusp.S */
17extern int restore_image(void);
18
19/* Pointer to the temporary resume page tables */
20pgd_t *resume_pg_dir;
21
22/* The following three functions are based on the analogous code in
23 * arch/i386/mm/init.c
24 */
25
26/*
27 * Create a middle page table on a resume-safe page and put a pointer to it in
28 * the given global directory entry. This only returns the gd entry
29 * in non-PAE compilation mode, since the middle layer is folded.
30 */
31static pmd_t *resume_one_md_table_init(pgd_t *pgd)
32{
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 pud = pud_offset(pgd, 0);
43
44 BUG_ON(pmd_table != pmd_offset(pud, 0));
45#else
46 pud = pud_offset(pgd, 0);
47 pmd_table = pmd_offset(pud, 0);
48#endif
49
50 return pmd_table;
51}
52
53/*
54 * Create a page table on a resume-safe page and place a pointer to it in
55 * a middle page directory entry.
56 */
57static pte_t *resume_one_page_table_init(pmd_t *pmd)
58{
59 if (pmd_none(*pmd)) {
60 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
61 if (!page_table)
62 return NULL;
63
64 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
65
66 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
67
68 return page_table;
69 }
70
71 return pte_offset_kernel(pmd, 0);
72}
73
74/*
75 * This maps the physical memory to kernel virtual address space, a total
76 * of max_low_pfn pages, by creating page tables starting from address
77 * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
78 */
79static int resume_physical_mapping_init(pgd_t *pgd_base)
80{
81 unsigned long pfn;
82 pgd_t *pgd;
83 pmd_t *pmd;
84 pte_t *pte;
85 int pgd_idx, pmd_idx;
86
87 pgd_idx = pgd_index(PAGE_OFFSET);
88 pgd = pgd_base + pgd_idx;
89 pfn = 0;
90
91 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
92 pmd = resume_one_md_table_init(pgd);
93 if (!pmd)
94 return -ENOMEM;
95
96 if (pfn >= max_low_pfn)
97 continue;
98
99 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
100 if (pfn >= max_low_pfn)
101 break;
102
103 /* Map with big pages if possible, otherwise create
104 * normal page tables.
105 * NOTE: We can mark everything as executable here
106 */
107 if (cpu_has_pse) {
108 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
109 pfn += PTRS_PER_PTE;
110 } else {
111 pte_t *max_pte;
112
113 pte = resume_one_page_table_init(pmd);
114 if (!pte)
115 return -ENOMEM;
116
117 max_pte = pte + PTRS_PER_PTE;
118 for (; pte < max_pte; pte++, pfn++) {
119 if (pfn >= max_low_pfn)
120 break;
121
122 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
123 }
124 }
125 }
126 }
127 return 0;
128}
129
130static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
131{
132#ifdef CONFIG_X86_PAE
133 int i;
134
135 /* Init entries of the first-level page table to the zero page */
136 for (i = 0; i < PTRS_PER_PGD; i++)
137 set_pgd(pg_dir + i,
138 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
139#endif
140}
141
142int swsusp_arch_resume(void)
143{
144 int error;
145
146 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
147 if (!resume_pg_dir)
148 return -ENOMEM;
149
150 resume_init_first_level_page_table(resume_pg_dir);
151 error = resume_physical_mapping_init(resume_pg_dir);
152 if (error)
153 return error;
154
155 /* We have got enough memory and from now on we cannot recover */
156 restore_image();
157 return 0;
158}