hibernate_32.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05 
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/system.h>
14#include <asm/page.h>
15#include <asm/pgtable.h>
16#include <asm/mmzone.h>
17
18/* Defined in hibernate_asm_32.S */
19extern int restore_image(void);
20
21/* References to section boundaries */
22extern const void __nosave_begin, __nosave_end;
23
24/* Pointer to the temporary resume page tables */
25pgd_t *resume_pg_dir;
26
27/* The following three functions are based on the analogous code in
28 * arch/x86/mm/init_32.c
29 */
30
31/*
32 * Create a middle page table on a resume-safe page and put a pointer to it in
33 * the given global directory entry.  This only returns the gd entry
34 * in non-PAE compilation mode, since the middle layer is folded.
35 */
36static pmd_t *resume_one_md_table_init(pgd_t *pgd)
37{
38	pud_t *pud;
39	pmd_t *pmd_table;
40
41#ifdef CONFIG_X86_PAE
42	pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
43	if (!pmd_table)
44		return NULL;
45
46	set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
47	pud = pud_offset(pgd, 0);
48
49	BUG_ON(pmd_table != pmd_offset(pud, 0));
50#else
51	pud = pud_offset(pgd, 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 (cpu_has_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	resume_map_numa_kva(pgd_base);
134
135	return 0;
136}
137
138static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
139{
140#ifdef CONFIG_X86_PAE
141	int i;
142
143	/* Init entries of the first-level page table to the zero page */
144	for (i = 0; i < PTRS_PER_PGD; i++)
145		set_pgd(pg_dir + i,
146			__pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
147#endif
148}
149
150int swsusp_arch_resume(void)
151{
152	int error;
153
154	resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
155	if (!resume_pg_dir)
156		return -ENOMEM;
157
158	resume_init_first_level_page_table(resume_pg_dir);
159	error = resume_physical_mapping_init(resume_pg_dir);
160	if (error)
161		return error;
162
163	/* We have got enough memory and from now on we cannot recover */
164	restore_image();
165	return 0;
166}
167
168/*
169 *	pfn_is_nosave - check if given pfn is in the 'nosave' section
170 */
171
172int pfn_is_nosave(unsigned long pfn)
173{
174	unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
175	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
176	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
177}
178