arch/x86/power/hibernate_64.c

   1 /*
   2  * Hibernation support for x86-64
   3  *
   4  * Distribute under GPLv2
   5  *
   6  * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
   7  * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
   8  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
   9  */
  10
  11 #include <linux/gfp.h>
  12 #include <linux/smp.h>
  13 #include <linux/suspend.h>
  14 #include <linux/scatterlist.h>
  15 #include <linux/kdebug.h>
  16
  17 #include <crypto/hash.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/pgtable.h>
  24 #include <asm/mtrr.h>
  25 #include <asm/sections.h>
  26 #include <asm/suspend.h>
  27 #include <asm/tlbflush.h>
  28
  29 /* Defined in hibernate_asm_64.S */
  30 extern asmlinkage __visible int restore_image(void);
  31
  32 /*
  33  * Address to jump to in the last phase of restore in order to get to the image
  34  * kernel's text (this value is passed in the image header).
  35  */
  36 unsigned long restore_jump_address __visible;
  37 unsigned long jump_address_phys;
  38
  39 /*
  40  * Value of the cr3 register from before the hibernation (this value is passed
  41  * in the image header).
  42  */
  43 unsigned long restore_cr3 __visible;
  44
  45 unsigned long temp_level4_pgt __visible;
  46
  47 unsigned long relocated_restore_code __visible;
  48
  49 static int set_up_temporary_text_mapping(pgd_t *pgd)
  50 {
  51         pmd_t *pmd;
  52         pud_t *pud;
  53         p4d_t *p4d;
  54
  55         /*
  56          * The new mapping only has to cover the page containing the image
  57          * kernel's entry point (jump_address_phys), because the switch over to
  58          * it is carried out by relocated code running from a page allocated
  59          * specifically for this purpose and covered by the identity mapping, so
  60          * the temporary kernel text mapping is only needed for the final jump.
  61          * Moreover, in that mapping the virtual address of the image kernel's
  62          * entry point must be the same as its virtual address in the image
  63          * kernel (restore_jump_address), so the image kernel's
  64          * restore_registers() code doesn't find itself in a different area of
  65          * the virtual address space after switching over to the original page
  66          * tables used by the image kernel.
  67          */
  68
  69         if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
  70                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
  71                 if (!p4d)
  72                         return -ENOMEM;
  73         }
  74
  75         pud = (pud_t *)get_safe_page(GFP_ATOMIC);
  76         if (!pud)
  77                 return -ENOMEM;
  78
  79         pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
  80         if (!pmd)
  81                 return -ENOMEM;
  82
  83         set_pmd(pmd + pmd_index(restore_jump_address),
  84                 __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
  85         set_pud(pud + pud_index(restore_jump_address),
  86                 __pud(__pa(pmd) | _KERNPG_TABLE));
  87         if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
  88                 set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE));
  89                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE));
  90         } else {
  91                 /* No p4d for 4-level paging: point the pgd to the pud page table */
  92                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE));
  93         }
  94
  95         return 0;
  96 }
  97
  98 static void *alloc_pgt_page(void *context)
  99 {
 100         return (void *)get_safe_page(GFP_ATOMIC);
 101 }
 102
 103 static int set_up_temporary_mappings(void)
 104 {
 105         struct x86_mapping_info info = {
 106                 .alloc_pgt_page = alloc_pgt_page,
 107                 .page_flag      = __PAGE_KERNEL_LARGE_EXEC,
 108                 .offset         = __PAGE_OFFSET,
 109         };
 110         unsigned long mstart, mend;
 111         pgd_t *pgd;
 112         int result;
 113         int i;
 114
 115         pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
 116         if (!pgd)
 117                 return -ENOMEM;
 118
 119         /* Prepare a temporary mapping for the kernel text */
 120         result = set_up_temporary_text_mapping(pgd);
 121         if (result)
 122                 return result;
 123
 124         /* Set up the direct mapping from scratch */
 125         for (i = 0; i < nr_pfn_mapped; i++) {
 126                 mstart = pfn_mapped[i].start << PAGE_SHIFT;
 127                 mend   = pfn_mapped[i].end << PAGE_SHIFT;
 128
 129                 result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
 130                 if (result)
 131                         return result;
 132         }
 133
 134         temp_level4_pgt = __pa(pgd);
 135         return 0;
 136 }
 137
 138 static int relocate_restore_code(void)
 139 {
 140         pgd_t *pgd;
 141         p4d_t *p4d;
 142         pud_t *pud;
 143         pmd_t *pmd;
 144         pte_t *pte;
 145
 146         relocated_restore_code = get_safe_page(GFP_ATOMIC);
 147         if (!relocated_restore_code)
 148                 return -ENOMEM;
 149
 150         memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
 151
 152         /* Make the page containing the relocated code executable */
 153         pgd = (pgd_t *)__va(read_cr3_pa()) +
 154                 pgd_index(relocated_restore_code);
 155         p4d = p4d_offset(pgd, relocated_restore_code);
 156         if (p4d_large(*p4d)) {
 157                 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
 158                 goto out;
 159         }
 160         pud = pud_offset(p4d, relocated_restore_code);
 161         if (pud_large(*pud)) {
 162                 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
 163                 goto out;
 164         }
 165         pmd = pmd_offset(pud, relocated_restore_code);
 166         if (pmd_large(*pmd)) {
 167                 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
 168                 goto out;
 169         }
 170         pte = pte_offset_kernel(pmd, relocated_restore_code);
 171         set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
 172 out:
 173         __flush_tlb_all();
 174         return 0;
 175 }
 176
 177 int swsusp_arch_resume(void)
 178 {
 179         int error;
 180
 181         /* We have got enough memory and from now on we cannot recover */
 182         error = set_up_temporary_mappings();
 183         if (error)
 184                 return error;
 185
 186         error = relocate_restore_code();
 187         if (error)
 188                 return error;
 189
 190         restore_image();
 191         return 0;
 192 }
 193
 194 /*
 195  *      pfn_is_nosave - check if given pfn is in the 'nosave' section
 196  */
 197
 198 int pfn_is_nosave(unsigned long pfn)
 199 {
 200         unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
 201         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
 202         return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
 203 }
 204
 205 #define MD5_DIGEST_SIZE 16
 206
 207 struct restore_data_record {
 208         unsigned long jump_address;
 209         unsigned long jump_address_phys;
 210         unsigned long cr3;
 211         unsigned long magic;
 212         u8 e820_digest[MD5_DIGEST_SIZE];
 213 };
 214
 215 #define RESTORE_MAGIC   0x23456789ABCDEF01UL
 216
 217 #if IS_BUILTIN(CONFIG_CRYPTO_MD5)
 218 /**
 219  * get_e820_md5 - calculate md5 according to given e820 table
 220  *
 221  * @table: the e820 table to be calculated
 222  * @buf: the md5 result to be stored to
 223  */
 224 static int get_e820_md5(struct e820_table *table, void *buf)
 225 {
 226         struct scatterlist sg;
 227         struct crypto_ahash *tfm;
 228         int size;
 229         int ret = 0;
 230
 231         tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
 232         if (IS_ERR(tfm))
 233                 return -ENOMEM;
 234
 235         {
 236                 AHASH_REQUEST_ON_STACK(req, tfm);
 237                 size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
 238                 ahash_request_set_tfm(req, tfm);
 239                 sg_init_one(&sg, (u8 *)table, size);
 240                 ahash_request_set_callback(req, 0, NULL, NULL);
 241                 ahash_request_set_crypt(req, &sg, buf, size);
 242
 243                 if (crypto_ahash_digest(req))
 244                         ret = -EINVAL;
 245                 ahash_request_zero(req);
 246         }
 247         crypto_free_ahash(tfm);
 248
 249         return ret;
 250 }
 251
 252 static void hibernation_e820_save(void *buf)
 253 {
 254         get_e820_md5(e820_table_firmware, buf);
 255 }
 256
 257 static bool hibernation_e820_mismatch(void *buf)
 258 {
 259         int ret;
 260         u8 result[MD5_DIGEST_SIZE];
 261
 262         memset(result, 0, MD5_DIGEST_SIZE);
 263         /* If there is no digest in suspend kernel, let it go. */
 264         if (!memcmp(result, buf, MD5_DIGEST_SIZE))
 265                 return false;
 266
 267         ret = get_e820_md5(e820_table_firmware, result);
 268         if (ret)
 269                 return true;
 270
 271         return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
 272 }
 273 #else
 274 static void hibernation_e820_save(void *buf)
 275 {
 276 }
 277
 278 static bool hibernation_e820_mismatch(void *buf)
 279 {
 280         /* If md5 is not builtin for restore kernel, let it go. */
 281         return false;
 282 }
 283 #endif
 284
 285 /**
 286  *      arch_hibernation_header_save - populate the architecture specific part
 287  *              of a hibernation image header
 288  *      @addr: address to save the data at
 289  */
 290 int arch_hibernation_header_save(void *addr, unsigned int max_size)
 291 {
 292         struct restore_data_record *rdr = addr;
 293
 294         if (max_size < sizeof(struct restore_data_record))
 295                 return -EOVERFLOW;
 296         rdr->jump_address = (unsigned long)restore_registers;
 297         rdr->jump_address_phys = __pa_symbol(restore_registers);
 298         rdr->cr3 = restore_cr3;
 299         rdr->magic = RESTORE_MAGIC;
 300
 301         hibernation_e820_save(rdr->e820_digest);
 302
 303         return 0;
 304 }
 305
 306 /**
 307  *      arch_hibernation_header_restore - read the architecture specific data
 308  *              from the hibernation image header
 309  *      @addr: address to read the data from
 310  */
 311 int arch_hibernation_header_restore(void *addr)
 312 {
 313         struct restore_data_record *rdr = addr;
 314
 315         restore_jump_address = rdr->jump_address;
 316         jump_address_phys = rdr->jump_address_phys;
 317         restore_cr3 = rdr->cr3;
 318
 319         if (rdr->magic != RESTORE_MAGIC) {
 320                 pr_crit("Unrecognized hibernate image header format!\n");
 321                 return -EINVAL;
 322         }
 323
 324         if (hibernation_e820_mismatch(rdr->e820_digest)) {
 325                 pr_crit("Hibernate inconsistent memory map detected!\n");
 326                 return -ENODEV;
 327         }
 328
 329         return 0;
 330 }