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 } 200