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 #include <linux/cpu.h> 15 #include <linux/pgtable.h> 16 #include <linux/types.h> 17 #include <linux/crc32.h> 18 19 #include <asm/e820/api.h> 20 #include <asm/init.h> 21 #include <asm/proto.h> 22 #include <asm/page.h> 23 #include <asm/mtrr.h> 24 #include <asm/sections.h> 25 #include <asm/suspend.h> 26 #include <asm/tlbflush.h> 27 28 /* 29 * Address to jump to in the last phase of restore in order to get to the image 30 * kernel's text (this value is passed in the image header). 31 */ 32 unsigned long restore_jump_address __visible; 33 unsigned long jump_address_phys; 34 35 /* 36 * Value of the cr3 register from before the hibernation (this value is passed 37 * in the image header). 38 */ 39 unsigned long restore_cr3 __visible; 40 unsigned long temp_pgt __visible; 41 unsigned long relocated_restore_code __visible; 42 43 /** 44 * pfn_is_nosave - check if given pfn is in the 'nosave' section 45 */ 46 int pfn_is_nosave(unsigned long pfn) 47 { 48 unsigned long nosave_begin_pfn; 49 unsigned long nosave_end_pfn; 50 51 nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; 52 nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT; 53 54 return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn; 55 } 56 57 struct restore_data_record { 58 unsigned long jump_address; 59 unsigned long jump_address_phys; 60 unsigned long cr3; 61 unsigned long magic; 62 unsigned long e820_checksum; 63 }; 64 65 /** 66 * compute_e820_crc32 - calculate crc32 of a given e820 table 67 * 68 * @table: the e820 table to be calculated 69 * 70 * Return: the resulting checksum 71 */ 72 static inline u32 compute_e820_crc32(struct e820_table *table) 73 { 74 int size = offsetof(struct e820_table, entries) + 75 sizeof(struct e820_entry) * table->nr_entries; 76 77 return ~crc32_le(~0, (unsigned char const *)table, size); 78 } 79 80 #ifdef CONFIG_X86_64 81 #define RESTORE_MAGIC 0x23456789ABCDEF02UL 82 #else 83 #define RESTORE_MAGIC 0x12345679UL 84 #endif 85 86 /** 87 * arch_hibernation_header_save - populate the architecture specific part 88 * of a hibernation image header 89 * @addr: address to save the data at 90 */ 91 int arch_hibernation_header_save(void *addr, unsigned int max_size) 92 { 93 struct restore_data_record *rdr = addr; 94 95 if (max_size < sizeof(struct restore_data_record)) 96 return -EOVERFLOW; 97 rdr->magic = RESTORE_MAGIC; 98 rdr->jump_address = (unsigned long)restore_registers; 99 rdr->jump_address_phys = __pa_symbol(restore_registers); 100 101 /* 102 * The restore code fixes up CR3 and CR4 in the following sequence: 103 * 104 * [in hibernation asm] 105 * 1. CR3 <= temporary page tables 106 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us) 107 * 3. CR3 <= rdr->cr3 108 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel) 109 * [in restore_processor_state()] 110 * 5. CR4 <= saved CR4 111 * 6. CR3 <= saved CR3 112 * 113 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling 114 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so 115 * rdr->cr3 needs to point to valid page tables but must not 116 * have any of the PCID bits set. 117 */ 118 rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK; 119 120 rdr->e820_checksum = compute_e820_crc32(e820_table_firmware); 121 return 0; 122 } 123 124 /** 125 * arch_hibernation_header_restore - read the architecture specific data 126 * from the hibernation image header 127 * @addr: address to read the data from 128 */ 129 int arch_hibernation_header_restore(void *addr) 130 { 131 struct restore_data_record *rdr = addr; 132 133 if (rdr->magic != RESTORE_MAGIC) { 134 pr_crit("Unrecognized hibernate image header format!\n"); 135 return -EINVAL; 136 } 137 138 restore_jump_address = rdr->jump_address; 139 jump_address_phys = rdr->jump_address_phys; 140 restore_cr3 = rdr->cr3; 141 142 if (rdr->e820_checksum != compute_e820_crc32(e820_table_firmware)) { 143 pr_crit("Hibernate inconsistent memory map detected!\n"); 144 return -ENODEV; 145 } 146 147 return 0; 148 } 149 150 int relocate_restore_code(void) 151 { 152 pgd_t *pgd; 153 p4d_t *p4d; 154 pud_t *pud; 155 pmd_t *pmd; 156 pte_t *pte; 157 158 relocated_restore_code = get_safe_page(GFP_ATOMIC); 159 if (!relocated_restore_code) 160 return -ENOMEM; 161 162 memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE); 163 164 /* Make the page containing the relocated code executable */ 165 pgd = (pgd_t *)__va(read_cr3_pa()) + 166 pgd_index(relocated_restore_code); 167 p4d = p4d_offset(pgd, relocated_restore_code); 168 if (p4d_large(*p4d)) { 169 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX)); 170 goto out; 171 } 172 pud = pud_offset(p4d, relocated_restore_code); 173 if (pud_large(*pud)) { 174 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX)); 175 goto out; 176 } 177 pmd = pmd_offset(pud, relocated_restore_code); 178 if (pmd_large(*pmd)) { 179 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX)); 180 goto out; 181 } 182 pte = pte_offset_kernel(pmd, relocated_restore_code); 183 set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX)); 184 out: 185 __flush_tlb_all(); 186 return 0; 187 } 188 189 int arch_resume_nosmt(void) 190 { 191 int ret = 0; 192 /* 193 * We reached this while coming out of hibernation. This means 194 * that SMT siblings are sleeping in hlt, as mwait is not safe 195 * against control transition during resume (see comment in 196 * hibernate_resume_nonboot_cpu_disable()). 197 * 198 * If the resumed kernel has SMT disabled, we have to take all the 199 * SMT siblings out of hlt, and offline them again so that they 200 * end up in mwait proper. 201 * 202 * Called with hotplug disabled. 203 */ 204 cpu_hotplug_enable(); 205 if (cpu_smt_control == CPU_SMT_DISABLED || 206 cpu_smt_control == CPU_SMT_FORCE_DISABLED) { 207 enum cpuhp_smt_control old = cpu_smt_control; 208 209 ret = cpuhp_smt_enable(); 210 if (ret) 211 goto out; 212 ret = cpuhp_smt_disable(old); 213 if (ret) 214 goto out; 215 } 216 out: 217 cpu_hotplug_disable(); 218 return ret; 219 } 220