1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Hibernation support specific for i386 - temporary page tables 4 * 5 * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl> 6 */ 7 8 #include <linux/gfp.h> 9 #include <linux/suspend.h> 10 #include <linux/memblock.h> 11 #include <linux/pgtable.h> 12 13 #include <asm/page.h> 14 #include <asm/mmzone.h> 15 #include <asm/sections.h> 16 #include <asm/suspend.h> 17 18 /* Pointer to the temporary resume page tables */ 19 pgd_t *resume_pg_dir; 20 21 /* The following three functions are based on the analogous code in 22 * arch/x86/mm/init_32.c 23 */ 24 25 /* 26 * Create a middle page table on a resume-safe page and put a pointer to it in 27 * the given global directory entry. This only returns the gd entry 28 * in non-PAE compilation mode, since the middle layer is folded. 29 */ 30 static pmd_t *resume_one_md_table_init(pgd_t *pgd) 31 { 32 p4d_t *p4d; 33 pud_t *pud; 34 pmd_t *pmd_table; 35 36 #ifdef CONFIG_X86_PAE 37 pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC); 38 if (!pmd_table) 39 return NULL; 40 41 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 42 p4d = p4d_offset(pgd, 0); 43 pud = pud_offset(p4d, 0); 44 45 BUG_ON(pmd_table != pmd_offset(pud, 0)); 46 #else 47 p4d = p4d_offset(pgd, 0); 48 pud = pud_offset(p4d, 0); 49 pmd_table = pmd_offset(pud, 0); 50 #endif 51 52 return pmd_table; 53 } 54 55 /* 56 * Create a page table on a resume-safe page and place a pointer to it in 57 * a middle page directory entry. 58 */ 59 static pte_t *resume_one_page_table_init(pmd_t *pmd) 60 { 61 if (pmd_none(*pmd)) { 62 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC); 63 if (!page_table) 64 return NULL; 65 66 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 67 68 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 69 70 return page_table; 71 } 72 73 return pte_offset_kernel(pmd, 0); 74 } 75 76 /* 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. 80 */ 81 static int resume_physical_mapping_init(pgd_t *pgd_base) 82 { 83 unsigned long pfn; 84 pgd_t *pgd; 85 pmd_t *pmd; 86 pte_t *pte; 87 int pgd_idx, pmd_idx; 88 89 pgd_idx = pgd_index(PAGE_OFFSET); 90 pgd = pgd_base + pgd_idx; 91 pfn = 0; 92 93 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 94 pmd = resume_one_md_table_init(pgd); 95 if (!pmd) 96 return -ENOMEM; 97 98 if (pfn >= max_low_pfn) 99 continue; 100 101 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) { 102 if (pfn >= max_low_pfn) 103 break; 104 105 /* Map with big pages if possible, otherwise create 106 * normal page tables. 107 * NOTE: We can mark everything as executable here 108 */ 109 if (boot_cpu_has(X86_FEATURE_PSE)) { 110 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC)); 111 pfn += PTRS_PER_PTE; 112 } else { 113 pte_t *max_pte; 114 115 pte = resume_one_page_table_init(pmd); 116 if (!pte) 117 return -ENOMEM; 118 119 max_pte = pte + PTRS_PER_PTE; 120 for (; pte < max_pte; pte++, pfn++) { 121 if (pfn >= max_low_pfn) 122 break; 123 124 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); 125 } 126 } 127 } 128 } 129 130 return 0; 131 } 132 133 static inline void resume_init_first_level_page_table(pgd_t *pg_dir) 134 { 135 #ifdef CONFIG_X86_PAE 136 int i; 137 138 /* Init entries of the first-level page table to the zero page */ 139 for (i = 0; i < PTRS_PER_PGD; i++) 140 set_pgd(pg_dir + i, 141 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT)); 142 #endif 143 } 144 145 static int set_up_temporary_text_mapping(pgd_t *pgd_base) 146 { 147 pgd_t *pgd; 148 pmd_t *pmd; 149 pte_t *pte; 150 151 pgd = pgd_base + pgd_index(restore_jump_address); 152 153 pmd = resume_one_md_table_init(pgd); 154 if (!pmd) 155 return -ENOMEM; 156 157 if (boot_cpu_has(X86_FEATURE_PSE)) { 158 set_pmd(pmd + pmd_index(restore_jump_address), 159 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(PAGE_KERNEL_LARGE_EXEC))); 160 } else { 161 pte = resume_one_page_table_init(pmd); 162 if (!pte) 163 return -ENOMEM; 164 set_pte(pte + pte_index(restore_jump_address), 165 __pte((jump_address_phys & PAGE_MASK) | pgprot_val(PAGE_KERNEL_EXEC))); 166 } 167 168 return 0; 169 } 170 171 asmlinkage int swsusp_arch_resume(void) 172 { 173 int error; 174 175 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); 176 if (!resume_pg_dir) 177 return -ENOMEM; 178 179 resume_init_first_level_page_table(resume_pg_dir); 180 181 error = set_up_temporary_text_mapping(resume_pg_dir); 182 if (error) 183 return error; 184 185 error = resume_physical_mapping_init(resume_pg_dir); 186 if (error) 187 return error; 188 189 temp_pgt = __pa(resume_pg_dir); 190 191 error = relocate_restore_code(); 192 if (error) 193 return error; 194 195 /* We have got enough memory and from now on we cannot recover */ 196 restore_image(); 197 return 0; 198 } 199