2 * Hibernation support specific for i386 - temporary page tables
4 * Distribute under GPLv2
6 * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
10 #include <linux/suspend.h>
11 #include <linux/bootmem.h>
14 #include <asm/pgtable.h>
15 #include <asm/mmzone.h>
16 #include <asm/sections.h>
18 /* Defined in hibernate_asm_32.S */
19 extern int restore_image(void);
21 /* Pointer to the temporary resume page tables */
24 /* The following three functions are based on the analogous code in
25 * arch/x86/mm/init_32.c
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.
33 static pmd_t
*resume_one_md_table_init(pgd_t
*pgd
)
39 pmd_table
= (pmd_t
*)get_safe_page(GFP_ATOMIC
);
43 set_pgd(pgd
, __pgd(__pa(pmd_table
) | _PAGE_PRESENT
));
44 pud
= pud_offset(pgd
, 0);
46 BUG_ON(pmd_table
!= pmd_offset(pud
, 0));
48 pud
= pud_offset(pgd
, 0);
49 pmd_table
= pmd_offset(pud
, 0);
56 * Create a page table on a resume-safe page and place a pointer to it in
57 * a middle page directory entry.
59 static pte_t
*resume_one_page_table_init(pmd_t
*pmd
)
62 pte_t
*page_table
= (pte_t
*)get_safe_page(GFP_ATOMIC
);
66 set_pmd(pmd
, __pmd(__pa(page_table
) | _PAGE_TABLE
));
68 BUG_ON(page_table
!= pte_offset_kernel(pmd
, 0));
73 return pte_offset_kernel(pmd
, 0);
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.
81 static int resume_physical_mapping_init(pgd_t
*pgd_base
)
89 pgd_idx
= pgd_index(PAGE_OFFSET
);
90 pgd
= pgd_base
+ pgd_idx
;
93 for (; pgd_idx
< PTRS_PER_PGD
; pgd
++, pgd_idx
++) {
94 pmd
= resume_one_md_table_init(pgd
);
98 if (pfn
>= max_low_pfn
)
101 for (pmd_idx
= 0; pmd_idx
< PTRS_PER_PMD
; pmd
++, pmd_idx
++) {
102 if (pfn
>= max_low_pfn
)
105 /* Map with big pages if possible, otherwise create
106 * normal page tables.
107 * NOTE: We can mark everything as executable here
110 set_pmd(pmd
, pfn_pmd(pfn
, PAGE_KERNEL_LARGE_EXEC
));
115 pte
= resume_one_page_table_init(pmd
);
119 max_pte
= pte
+ PTRS_PER_PTE
;
120 for (; pte
< max_pte
; pte
++, pfn
++) {
121 if (pfn
>= max_low_pfn
)
124 set_pte(pte
, pfn_pte(pfn
, PAGE_KERNEL_EXEC
));
133 static inline void resume_init_first_level_page_table(pgd_t
*pg_dir
)
135 #ifdef CONFIG_X86_PAE
138 /* Init entries of the first-level page table to the zero page */
139 for (i
= 0; i
< PTRS_PER_PGD
; i
++)
141 __pgd(__pa(empty_zero_page
) | _PAGE_PRESENT
));
145 int swsusp_arch_resume(void)
149 resume_pg_dir
= (pgd_t
*)get_safe_page(GFP_ATOMIC
);
153 resume_init_first_level_page_table(resume_pg_dir
);
154 error
= resume_physical_mapping_init(resume_pg_dir
);
158 /* We have got enough memory and from now on we cannot recover */
164 * pfn_is_nosave - check if given pfn is in the 'nosave' section
167 int pfn_is_nosave(unsigned long pfn
)
169 unsigned long nosave_begin_pfn
= __pa_symbol(&__nosave_begin
) >> PAGE_SHIFT
;
170 unsigned long nosave_end_pfn
= PAGE_ALIGN(__pa_symbol(&__nosave_end
)) >> PAGE_SHIFT
;
171 return (pfn
>= nosave_begin_pfn
) && (pfn
< nosave_end_pfn
);
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