arch/x86/power/hibernate_32.c

   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/memblock.h>
  12
  13 #include <asm/page.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/mmzone.h>
  16 #include <asm/sections.h>
  17 #include <asm/suspend.h>
  18
  19 /* Pointer to the temporary resume page tables */
  20 pgd_t *resume_pg_dir;
  21
  22 /* The following three functions are based on the analogous code in
  23  * arch/x86/mm/init_32.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  */
  31 static pmd_t *resume_one_md_table_init(pgd_t *pgd)
  32 {
  33         p4d_t *p4d;
  34         pud_t *pud;
  35         pmd_t *pmd_table;
  36
  37 #ifdef CONFIG_X86_PAE
  38         pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
  39         if (!pmd_table)
  40                 return NULL;
  41
  42         set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  43         p4d = p4d_offset(pgd, 0);
  44         pud = pud_offset(p4d, 0);
  45
  46         BUG_ON(pmd_table != pmd_offset(pud, 0));
  47 #else
  48         p4d = p4d_offset(pgd, 0);
  49         pud = pud_offset(p4d, 0);
  50         pmd_table = pmd_offset(pud, 0);
  51 #endif
  52
  53         return pmd_table;
  54 }
  55
  56 /*
  57  * Create a page table on a resume-safe page and place a pointer to it in
  58  * a middle page directory entry.
  59  */
  60 static pte_t *resume_one_page_table_init(pmd_t *pmd)
  61 {
  62         if (pmd_none(*pmd)) {
  63                 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
  64                 if (!page_table)
  65                         return NULL;
  66
  67                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
  68
  69                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
  70
  71                 return page_table;
  72         }
  73
  74         return pte_offset_kernel(pmd, 0);
  75 }
  76
  77 /*
  78  * This maps the physical memory to kernel virtual address space, a total
  79  * of max_low_pfn pages, by creating page tables starting from address
  80  * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
  81  */
  82 static int resume_physical_mapping_init(pgd_t *pgd_base)
  83 {
  84         unsigned long pfn;
  85         pgd_t *pgd;
  86         pmd_t *pmd;
  87         pte_t *pte;
  88         int pgd_idx, pmd_idx;
  89
  90         pgd_idx = pgd_index(PAGE_OFFSET);
  91         pgd = pgd_base + pgd_idx;
  92         pfn = 0;
  93
  94         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
  95                 pmd = resume_one_md_table_init(pgd);
  96                 if (!pmd)
  97                         return -ENOMEM;
  98
  99                 if (pfn >= max_low_pfn)
 100                         continue;
 101
 102                 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
 103                         if (pfn >= max_low_pfn)
 104                                 break;
 105
 106                         /* Map with big pages if possible, otherwise create
 107                          * normal page tables.
 108                          * NOTE: We can mark everything as executable here
 109                          */
 110                         if (boot_cpu_has(X86_FEATURE_PSE)) {
 111                                 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
 112                                 pfn += PTRS_PER_PTE;
 113                         } else {
 114                                 pte_t *max_pte;
 115
 116                                 pte = resume_one_page_table_init(pmd);
 117                                 if (!pte)
 118                                         return -ENOMEM;
 119
 120                                 max_pte = pte + PTRS_PER_PTE;
 121                                 for (; pte < max_pte; pte++, pfn++) {
 122                                         if (pfn >= max_low_pfn)
 123                                                 break;
 124
 125                                         set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 126                                 }
 127                         }
 128                 }
 129         }
 130
 131         return 0;
 132 }
 133
 134 static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
 135 {
 136 #ifdef CONFIG_X86_PAE
 137         int i;
 138
 139         /* Init entries of the first-level page table to the zero page */
 140         for (i = 0; i < PTRS_PER_PGD; i++)
 141                 set_pgd(pg_dir + i,
 142                         __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
 143 #endif
 144 }
 145
 146 static int set_up_temporary_text_mapping(pgd_t *pgd_base)
 147 {
 148         pgd_t *pgd;
 149         pmd_t *pmd;
 150         pte_t *pte;
 151
 152         pgd = pgd_base + pgd_index(restore_jump_address);
 153
 154         pmd = resume_one_md_table_init(pgd);
 155         if (!pmd)
 156                 return -ENOMEM;
 157
 158         if (boot_cpu_has(X86_FEATURE_PSE)) {
 159                 set_pmd(pmd + pmd_index(restore_jump_address),
 160                 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(PAGE_KERNEL_LARGE_EXEC)));
 161         } else {
 162                 pte = resume_one_page_table_init(pmd);
 163                 if (!pte)
 164                         return -ENOMEM;
 165                 set_pte(pte + pte_index(restore_jump_address),
 166                 __pte((jump_address_phys & PAGE_MASK) | pgprot_val(PAGE_KERNEL_EXEC)));
 167         }
 168
 169         return 0;
 170 }
 171
 172 asmlinkage int swsusp_arch_resume(void)
 173 {
 174         int error;
 175
 176         resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
 177         if (!resume_pg_dir)
 178                 return -ENOMEM;
 179
 180         resume_init_first_level_page_table(resume_pg_dir);
 181
 182         error = set_up_temporary_text_mapping(resume_pg_dir);
 183         if (error)
 184                 return error;
 185
 186         error = resume_physical_mapping_init(resume_pg_dir);
 187         if (error)
 188                 return error;
 189
 190         temp_pgt = __pa(resume_pg_dir);
 191
 192         error = relocate_restore_code();
 193         if (error)
 194                 return error;
 195
 196         /* We have got enough memory and from now on we cannot recover */
 197         restore_image();
 198         return 0;
 199 }