1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Hibernation support for x86 4 * 5 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl> 6 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz> 7 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org> 8 */ 9 #include <linux/gfp.h> 10 #include <linux/smp.h> 11 #include <linux/suspend.h> 12 #include <linux/scatterlist.h> 13 #include <linux/kdebug.h> 14 15 #include <crypto/hash.h> 16 17 #include <asm/e820/api.h> 18 #include <asm/init.h> 19 #include <asm/proto.h> 20 #include <asm/page.h> 21 #include <asm/pgtable.h> 22 #include <asm/mtrr.h> 23 #include <asm/sections.h> 24 #include <asm/suspend.h> 25 #include <asm/tlbflush.h> 26 27 /* 28 * Address to jump to in the last phase of restore in order to get to the image 29 * kernel's text (this value is passed in the image header). 30 */ 31 unsigned long restore_jump_address __visible; 32 unsigned long jump_address_phys; 33 34 /* 35 * Value of the cr3 register from before the hibernation (this value is passed 36 * in the image header). 37 */ 38 unsigned long restore_cr3 __visible; 39 unsigned long temp_pgt __visible; 40 unsigned long relocated_restore_code __visible; 41 42 /** 43 * pfn_is_nosave - check if given pfn is in the 'nosave' section 44 */ 45 int pfn_is_nosave(unsigned long pfn) 46 { 47 unsigned long nosave_begin_pfn; 48 unsigned long nosave_end_pfn; 49 50 nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; 51 nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT; 52 53 return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn; 54 } 55 56 57 #define MD5_DIGEST_SIZE 16 58 59 struct restore_data_record { 60 unsigned long jump_address; 61 unsigned long jump_address_phys; 62 unsigned long cr3; 63 unsigned long magic; 64 u8 e820_digest[MD5_DIGEST_SIZE]; 65 }; 66 67 #if IS_BUILTIN(CONFIG_CRYPTO_MD5) 68 /** 69 * get_e820_md5 - calculate md5 according to given e820 table 70 * 71 * @table: the e820 table to be calculated 72 * @buf: the md5 result to be stored to 73 */ 74 static int get_e820_md5(struct e820_table *table, void *buf) 75 { 76 struct crypto_shash *tfm; 77 struct shash_desc *desc; 78 int size; 79 int ret = 0; 80 81 tfm = crypto_alloc_shash("md5", 0, 0); 82 if (IS_ERR(tfm)) 83 return -ENOMEM; 84 85 desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), 86 GFP_KERNEL); 87 if (!desc) { 88 ret = -ENOMEM; 89 goto free_tfm; 90 } 91 92 desc->tfm = tfm; 93 94 size = offsetof(struct e820_table, entries) + 95 sizeof(struct e820_entry) * table->nr_entries; 96 97 if (crypto_shash_digest(desc, (u8 *)table, size, buf)) 98 ret = -EINVAL; 99 100 kzfree(desc); 101 102 free_tfm: 103 crypto_free_shash(tfm); 104 return ret; 105 } 106 107 static int hibernation_e820_save(void *buf) 108 { 109 return get_e820_md5(e820_table_firmware, buf); 110 } 111 112 static bool hibernation_e820_mismatch(void *buf) 113 { 114 int ret; 115 u8 result[MD5_DIGEST_SIZE]; 116 117 memset(result, 0, MD5_DIGEST_SIZE); 118 /* If there is no digest in suspend kernel, let it go. */ 119 if (!memcmp(result, buf, MD5_DIGEST_SIZE)) 120 return false; 121 122 ret = get_e820_md5(e820_table_firmware, result); 123 if (ret) 124 return true; 125 126 return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false; 127 } 128 #else 129 static int hibernation_e820_save(void *buf) 130 { 131 return 0; 132 } 133 134 static bool hibernation_e820_mismatch(void *buf) 135 { 136 /* If md5 is not builtin for restore kernel, let it go. */ 137 return false; 138 } 139 #endif 140 141 #ifdef CONFIG_X86_64 142 #define RESTORE_MAGIC 0x23456789ABCDEF01UL 143 #else 144 #define RESTORE_MAGIC 0x12345678UL 145 #endif 146 147 /** 148 * arch_hibernation_header_save - populate the architecture specific part 149 * of a hibernation image header 150 * @addr: address to save the data at 151 */ 152 int arch_hibernation_header_save(void *addr, unsigned int max_size) 153 { 154 struct restore_data_record *rdr = addr; 155 156 if (max_size < sizeof(struct restore_data_record)) 157 return -EOVERFLOW; 158 rdr->magic = RESTORE_MAGIC; 159 rdr->jump_address = (unsigned long)restore_registers; 160 rdr->jump_address_phys = __pa_symbol(restore_registers); 161 162 /* 163 * The restore code fixes up CR3 and CR4 in the following sequence: 164 * 165 * [in hibernation asm] 166 * 1. CR3 <= temporary page tables 167 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us) 168 * 3. CR3 <= rdr->cr3 169 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel) 170 * [in restore_processor_state()] 171 * 5. CR4 <= saved CR4 172 * 6. CR3 <= saved CR3 173 * 174 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling 175 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so 176 * rdr->cr3 needs to point to valid page tables but must not 177 * have any of the PCID bits set. 178 */ 179 rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK; 180 181 return hibernation_e820_save(rdr->e820_digest); 182 } 183 184 /** 185 * arch_hibernation_header_restore - read the architecture specific data 186 * from the hibernation image header 187 * @addr: address to read the data from 188 */ 189 int arch_hibernation_header_restore(void *addr) 190 { 191 struct restore_data_record *rdr = addr; 192 193 if (rdr->magic != RESTORE_MAGIC) { 194 pr_crit("Unrecognized hibernate image header format!\n"); 195 return -EINVAL; 196 } 197 198 restore_jump_address = rdr->jump_address; 199 jump_address_phys = rdr->jump_address_phys; 200 restore_cr3 = rdr->cr3; 201 202 if (hibernation_e820_mismatch(rdr->e820_digest)) { 203 pr_crit("Hibernate inconsistent memory map detected!\n"); 204 return -ENODEV; 205 } 206 207 return 0; 208 } 209 210 int relocate_restore_code(void) 211 { 212 pgd_t *pgd; 213 p4d_t *p4d; 214 pud_t *pud; 215 pmd_t *pmd; 216 pte_t *pte; 217 218 relocated_restore_code = get_safe_page(GFP_ATOMIC); 219 if (!relocated_restore_code) 220 return -ENOMEM; 221 222 memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE); 223 224 /* Make the page containing the relocated code executable */ 225 pgd = (pgd_t *)__va(read_cr3_pa()) + 226 pgd_index(relocated_restore_code); 227 p4d = p4d_offset(pgd, relocated_restore_code); 228 if (p4d_large(*p4d)) { 229 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX)); 230 goto out; 231 } 232 pud = pud_offset(p4d, relocated_restore_code); 233 if (pud_large(*pud)) { 234 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX)); 235 goto out; 236 } 237 pmd = pmd_offset(pud, relocated_restore_code); 238 if (pmd_large(*pmd)) { 239 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX)); 240 goto out; 241 } 242 pte = pte_offset_kernel(pmd, relocated_restore_code); 243 set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX)); 244 out: 245 __flush_tlb_all(); 246 return 0; 247 } 248