arch/x86/power/hibernate.c

   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         desc->flags = 0;
  94
  95         size = offsetof(struct e820_table, entries) +
  96                 sizeof(struct e820_entry) * table->nr_entries;
  97
  98         if (crypto_shash_digest(desc, (u8 *)table, size, buf))
  99                 ret = -EINVAL;
 100
 101         kzfree(desc);
 102
 103 free_tfm:
 104         crypto_free_shash(tfm);
 105         return ret;
 106 }
 107
 108 static int hibernation_e820_save(void *buf)
 109 {
 110         return get_e820_md5(e820_table_firmware, buf);
 111 }
 112
 113 static bool hibernation_e820_mismatch(void *buf)
 114 {
 115         int ret;
 116         u8 result[MD5_DIGEST_SIZE];
 117
 118         memset(result, 0, MD5_DIGEST_SIZE);
 119         /* If there is no digest in suspend kernel, let it go. */
 120         if (!memcmp(result, buf, MD5_DIGEST_SIZE))
 121                 return false;
 122
 123         ret = get_e820_md5(e820_table_firmware, result);
 124         if (ret)
 125                 return true;
 126
 127         return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
 128 }
 129 #else
 130 static int hibernation_e820_save(void *buf)
 131 {
 132         return 0;
 133 }
 134
 135 static bool hibernation_e820_mismatch(void *buf)
 136 {
 137         /* If md5 is not builtin for restore kernel, let it go. */
 138         return false;
 139 }
 140 #endif
 141
 142 #ifdef CONFIG_X86_64
 143 #define RESTORE_MAGIC   0x23456789ABCDEF01UL
 144 #else
 145 #define RESTORE_MAGIC   0x12345678UL
 146 #endif
 147
 148 /**
 149  *      arch_hibernation_header_save - populate the architecture specific part
 150  *              of a hibernation image header
 151  *      @addr: address to save the data at
 152  */
 153 int arch_hibernation_header_save(void *addr, unsigned int max_size)
 154 {
 155         struct restore_data_record *rdr = addr;
 156
 157         if (max_size < sizeof(struct restore_data_record))
 158                 return -EOVERFLOW;
 159         rdr->magic = RESTORE_MAGIC;
 160         rdr->jump_address = (unsigned long)restore_registers;
 161         rdr->jump_address_phys = __pa_symbol(restore_registers);
 162
 163         /*
 164          * The restore code fixes up CR3 and CR4 in the following sequence:
 165          *
 166          * [in hibernation asm]
 167          * 1. CR3 <= temporary page tables
 168          * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
 169          * 3. CR3 <= rdr->cr3
 170          * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
 171          * [in restore_processor_state()]
 172          * 5. CR4 <= saved CR4
 173          * 6. CR3 <= saved CR3
 174          *
 175          * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
 176          * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
 177          * rdr->cr3 needs to point to valid page tables but must not
 178          * have any of the PCID bits set.
 179          */
 180         rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
 181
 182         return hibernation_e820_save(rdr->e820_digest);
 183 }
 184
 185 /**
 186  *      arch_hibernation_header_restore - read the architecture specific data
 187  *              from the hibernation image header
 188  *      @addr: address to read the data from
 189  */
 190 int arch_hibernation_header_restore(void *addr)
 191 {
 192         struct restore_data_record *rdr = addr;
 193
 194         if (rdr->magic != RESTORE_MAGIC) {
 195                 pr_crit("Unrecognized hibernate image header format!\n");
 196                 return -EINVAL;
 197         }
 198
 199         restore_jump_address = rdr->jump_address;
 200         jump_address_phys = rdr->jump_address_phys;
 201         restore_cr3 = rdr->cr3;
 202
 203         if (hibernation_e820_mismatch(rdr->e820_digest)) {
 204                 pr_crit("Hibernate inconsistent memory map detected!\n");
 205                 return -ENODEV;
 206         }
 207
 208         return 0;
 209 }
 210
 211 int relocate_restore_code(void)
 212 {
 213         pgd_t *pgd;
 214         p4d_t *p4d;
 215         pud_t *pud;
 216         pmd_t *pmd;
 217         pte_t *pte;
 218
 219         relocated_restore_code = get_safe_page(GFP_ATOMIC);
 220         if (!relocated_restore_code)
 221                 return -ENOMEM;
 222
 223         memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
 224
 225         /* Make the page containing the relocated code executable */
 226         pgd = (pgd_t *)__va(read_cr3_pa()) +
 227                 pgd_index(relocated_restore_code);
 228         p4d = p4d_offset(pgd, relocated_restore_code);
 229         if (p4d_large(*p4d)) {
 230                 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
 231                 goto out;
 232         }
 233         pud = pud_offset(p4d, relocated_restore_code);
 234         if (pud_large(*pud)) {
 235                 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
 236                 goto out;
 237         }
 238         pmd = pmd_offset(pud, relocated_restore_code);
 239         if (pmd_large(*pmd)) {
 240                 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
 241                 goto out;
 242         }
 243         pte = pte_offset_kernel(pmd, relocated_restore_code);
 244         set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
 245 out:
 246         __flush_tlb_all();
 247         return 0;
 248 }