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/page.h> 14 #include <asm/pgtable.h> 15 #include <asm/mmzone.h> 16 #include <asm/sections.h> 17 18 /* Defined in hibernate_asm_32.S */ 19 extern int restore_image(void); 20 21 /* Pointer to the temporary resume page tables */ 22 pgd_t *resume_pg_dir; 23 24 /* The following three functions are based on the analogous code in 25 * arch/x86/mm/init_32.c 26 */ 27 28 /* 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. 32 */ 33 static pmd_t *resume_one_md_table_init(pgd_t *pgd) 34 { 35 p4d_t *p4d; 36 pud_t *pud; 37 pmd_t *pmd_table; 38 39 #ifdef CONFIG_X86_PAE 40 pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC); 41 if (!pmd_table) 42 return NULL; 43 44 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 45 p4d = p4d_offset(pgd, 0); 46 pud = pud_offset(p4d, 0); 47 48 BUG_ON(pmd_table != pmd_offset(pud, 0)); 49 #else 50 p4d = p4d_offset(pgd, 0); 51 pud = pud_offset(p4d, 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 */ 62 static 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 */ 84 static 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 (boot_cpu_has(X86_FEATURE_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 return 0; 134 } 135 136 static inline void resume_init_first_level_page_table(pgd_t *pg_dir) 137 { 138 #ifdef CONFIG_X86_PAE 139 int i; 140 141 /* Init entries of the first-level page table to the zero page */ 142 for (i = 0; i < PTRS_PER_PGD; i++) 143 set_pgd(pg_dir + i, 144 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT)); 145 #endif 146 } 147 148 asmlinkage int swsusp_arch_resume(void) 149 { 150 int error; 151 152 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); 153 if (!resume_pg_dir) 154 return -ENOMEM; 155 156 resume_init_first_level_page_table(resume_pg_dir); 157 error = resume_physical_mapping_init(resume_pg_dir); 158 if (error) 159 return error; 160 161 /* We have got enough memory and from now on we cannot recover */ 162 restore_image(); 163 return 0; 164 } 165 166 /* 167 * pfn_is_nosave - check if given pfn is in the 'nosave' section 168 */ 169 170 int pfn_is_nosave(unsigned long pfn) 171 { 172 unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; 173 unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT; 174 return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); 175 } 176