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 #include <linux/cpu.h>
  17
  18 #include <crypto/hash.h>
  19
  20 #include <asm/e820/api.h>
  21 #include <asm/init.h>
  22 #include <asm/proto.h>
  23 #include <asm/page.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/mtrr.h>
  26 #include <asm/sections.h>
  27 #include <asm/suspend.h>
  28 #include <asm/tlbflush.h>
  29
  30 /* Defined in hibernate_asm_64.S */
  31 extern asmlinkage __visible int restore_image(void);
  32
  33 /*
  34  * Address to jump to in the last phase of restore in order to get to the image
  35  * kernel's text (this value is passed in the image header).
  36  */
  37 unsigned long restore_jump_address __visible;
  38 unsigned long jump_address_phys;
  39
  40 /*
  41  * Value of the cr3 register from before the hibernation (this value is passed
  42  * in the image header).
  43  */
  44 unsigned long restore_cr3 __visible;
  45
  46 unsigned long temp_level4_pgt __visible;
  47
  48 unsigned long relocated_restore_code __visible;
  49
  50 static int set_up_temporary_text_mapping(pgd_t *pgd)
  51 {
  52         pmd_t *pmd;
  53         pud_t *pud;
  54         p4d_t *p4d;
  55
  56         /*
  57          * The new mapping only has to cover the page containing the image
  58          * kernel's entry point (jump_address_phys), because the switch over to
  59          * it is carried out by relocated code running from a page allocated
  60          * specifically for this purpose and covered by the identity mapping, so
  61          * the temporary kernel text mapping is only needed for the final jump.
  62          * Moreover, in that mapping the virtual address of the image kernel's
  63          * entry point must be the same as its virtual address in the image
  64          * kernel (restore_jump_address), so the image kernel's
  65          * restore_registers() code doesn't find itself in a different area of
  66          * the virtual address space after switching over to the original page
  67          * tables used by the image kernel.
  68          */
  69
  70         if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
  71                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
  72                 if (!p4d)
  73                         return -ENOMEM;
  74         }
  75
  76         pud = (pud_t *)get_safe_page(GFP_ATOMIC);
  77         if (!pud)
  78                 return -ENOMEM;
  79
  80         pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
  81         if (!pmd)
  82                 return -ENOMEM;
  83
  84         set_pmd(pmd + pmd_index(restore_jump_address),
  85                 __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
  86         set_pud(pud + pud_index(restore_jump_address),
  87                 __pud(__pa(pmd) | _KERNPG_TABLE));
  88         if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
  89                 set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE));
  90                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE));
  91         } else {
  92                 /* No p4d for 4-level paging: point the pgd to the pud page table */
  93                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE));
  94         }
  95
  96         return 0;
  97 }
  98
  99 static void *alloc_pgt_page(void *context)
 100 {
 101         return (void *)get_safe_page(GFP_ATOMIC);
 102 }
 103
 104 static int set_up_temporary_mappings(void)
 105 {
 106         struct x86_mapping_info info = {
 107                 .alloc_pgt_page = alloc_pgt_page,
 108                 .page_flag      = __PAGE_KERNEL_LARGE_EXEC,
 109                 .offset         = __PAGE_OFFSET,
 110         };
 111         unsigned long mstart, mend;
 112         pgd_t *pgd;
 113         int result;
 114         int i;
 115
 116         pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
 117         if (!pgd)
 118                 return -ENOMEM;
 119
 120         /* Prepare a temporary mapping for the kernel text */
 121         result = set_up_temporary_text_mapping(pgd);
 122         if (result)
 123                 return result;
 124
 125         /* Set up the direct mapping from scratch */
 126         for (i = 0; i < nr_pfn_mapped; i++) {
 127                 mstart = pfn_mapped[i].start << PAGE_SHIFT;
 128                 mend   = pfn_mapped[i].end << PAGE_SHIFT;
 129
 130                 result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
 131                 if (result)
 132                         return result;
 133         }
 134
 135         temp_level4_pgt = __pa(pgd);
 136         return 0;
 137 }
 138
 139 static int relocate_restore_code(void)
 140 {
 141         pgd_t *pgd;
 142         p4d_t *p4d;
 143         pud_t *pud;
 144         pmd_t *pmd;
 145         pte_t *pte;
 146
 147         relocated_restore_code = get_safe_page(GFP_ATOMIC);
 148         if (!relocated_restore_code)
 149                 return -ENOMEM;
 150
 151         memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
 152
 153         /* Make the page containing the relocated code executable */
 154         pgd = (pgd_t *)__va(read_cr3_pa()) +
 155                 pgd_index(relocated_restore_code);
 156         p4d = p4d_offset(pgd, relocated_restore_code);
 157         if (p4d_large(*p4d)) {
 158                 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
 159                 goto out;
 160         }
 161         pud = pud_offset(p4d, relocated_restore_code);
 162         if (pud_large(*pud)) {
 163                 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
 164                 goto out;
 165         }
 166         pmd = pmd_offset(pud, relocated_restore_code);
 167         if (pmd_large(*pmd)) {
 168                 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
 169                 goto out;
 170         }
 171         pte = pte_offset_kernel(pmd, relocated_restore_code);
 172         set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
 173 out:
 174         __flush_tlb_all();
 175         return 0;
 176 }
 177
 178 asmlinkage int swsusp_arch_resume(void)
 179 {
 180         int error;
 181
 182         /* We have got enough memory and from now on we cannot recover */
 183         error = set_up_temporary_mappings();
 184         if (error)
 185                 return error;
 186
 187         error = relocate_restore_code();
 188         if (error)
 189                 return error;
 190
 191         restore_image();
 192         return 0;
 193 }
 194
 195 /*
 196  *      pfn_is_nosave - check if given pfn is in the 'nosave' section
 197  */
 198
 199 int pfn_is_nosave(unsigned long pfn)
 200 {
 201         unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
 202         unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
 203         return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
 204 }
 205
 206 #define MD5_DIGEST_SIZE 16
 207
 208 struct restore_data_record {
 209         unsigned long jump_address;
 210         unsigned long jump_address_phys;
 211         unsigned long cr3;
 212         unsigned long magic;
 213         u8 e820_digest[MD5_DIGEST_SIZE];
 214 };
 215
 216 #define RESTORE_MAGIC   0x23456789ABCDEF01UL
 217
 218 #if IS_BUILTIN(CONFIG_CRYPTO_MD5)
 219 /**
 220  * get_e820_md5 - calculate md5 according to given e820 table
 221  *
 222  * @table: the e820 table to be calculated
 223  * @buf: the md5 result to be stored to
 224  */
 225 static int get_e820_md5(struct e820_table *table, void *buf)
 226 {
 227         struct scatterlist sg;
 228         struct crypto_ahash *tfm;
 229         int size;
 230         int ret = 0;
 231
 232         tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
 233         if (IS_ERR(tfm))
 234                 return -ENOMEM;
 235
 236         {
 237                 AHASH_REQUEST_ON_STACK(req, tfm);
 238                 size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
 239                 ahash_request_set_tfm(req, tfm);
 240                 sg_init_one(&sg, (u8 *)table, size);
 241                 ahash_request_set_callback(req, 0, NULL, NULL);
 242                 ahash_request_set_crypt(req, &sg, buf, size);
 243
 244                 if (crypto_ahash_digest(req))
 245                         ret = -EINVAL;
 246                 ahash_request_zero(req);
 247         }
 248         crypto_free_ahash(tfm);
 249
 250         return ret;
 251 }
 252
 253 static int hibernation_e820_save(void *buf)
 254 {
 255         return get_e820_md5(e820_table_firmware, buf);
 256 }
 257
 258 static bool hibernation_e820_mismatch(void *buf)
 259 {
 260         int ret;
 261         u8 result[MD5_DIGEST_SIZE];
 262
 263         memset(result, 0, MD5_DIGEST_SIZE);
 264         /* If there is no digest in suspend kernel, let it go. */
 265         if (!memcmp(result, buf, MD5_DIGEST_SIZE))
 266                 return false;
 267
 268         ret = get_e820_md5(e820_table_firmware, result);
 269         if (ret)
 270                 return true;
 271
 272         return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
 273 }
 274 #else
 275 static int hibernation_e820_save(void *buf)
 276 {
 277         return 0;
 278 }
 279
 280 static bool hibernation_e820_mismatch(void *buf)
 281 {
 282         /* If md5 is not builtin for restore kernel, let it go. */
 283         return false;
 284 }
 285 #endif
 286
 287 /**
 288  *      arch_hibernation_header_save - populate the architecture specific part
 289  *              of a hibernation image header
 290  *      @addr: address to save the data at
 291  */
 292 int arch_hibernation_header_save(void *addr, unsigned int max_size)
 293 {
 294         struct restore_data_record *rdr = addr;
 295
 296         if (max_size < sizeof(struct restore_data_record))
 297                 return -EOVERFLOW;
 298         rdr->jump_address = (unsigned long)restore_registers;
 299         rdr->jump_address_phys = __pa_symbol(restore_registers);
 300
 301         /*
 302          * The restore code fixes up CR3 and CR4 in the following sequence:
 303          *
 304          * [in hibernation asm]
 305          * 1. CR3 <= temporary page tables
 306          * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
 307          * 3. CR3 <= rdr->cr3
 308          * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
 309          * [in restore_processor_state()]
 310          * 5. CR4 <= saved CR4
 311          * 6. CR3 <= saved CR3
 312          *
 313          * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
 314          * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
 315          * rdr->cr3 needs to point to valid page tables but must not
 316          * have any of the PCID bits set.
 317          */
 318         rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
 319
 320         rdr->magic = RESTORE_MAGIC;
 321
 322         return hibernation_e820_save(rdr->e820_digest);
 323 }
 324
 325 /**
 326  *      arch_hibernation_header_restore - read the architecture specific data
 327  *              from the hibernation image header
 328  *      @addr: address to read the data from
 329  */
 330 int arch_hibernation_header_restore(void *addr)
 331 {
 332         struct restore_data_record *rdr = addr;
 333
 334         restore_jump_address = rdr->jump_address;
 335         jump_address_phys = rdr->jump_address_phys;
 336         restore_cr3 = rdr->cr3;
 337
 338         if (rdr->magic != RESTORE_MAGIC) {
 339                 pr_crit("Unrecognized hibernate image header format!\n");
 340                 return -EINVAL;
 341         }
 342
 343         if (hibernation_e820_mismatch(rdr->e820_digest)) {
 344                 pr_crit("Hibernate inconsistent memory map detected!\n");
 345                 return -ENODEV;
 346         }
 347
 348         return 0;
 349 }
 350
 351 int arch_resume_nosmt(void)
 352 {
 353         int ret = 0;
 354         /*
 355          * We reached this while coming out of hibernation. This means
 356          * that SMT siblings are sleeping in hlt, as mwait is not safe
 357          * against control transition during resume (see comment in
 358          * hibernate_resume_nonboot_cpu_disable()).
 359          *
 360          * If the resumed kernel has SMT disabled, we have to take all the
 361          * SMT siblings out of hlt, and offline them again so that they
 362          * end up in mwait proper.
 363          *
 364          * Called with hotplug disabled.
 365          */
 366         cpu_hotplug_enable();
 367         if (cpu_smt_control == CPU_SMT_DISABLED ||
 368                         cpu_smt_control == CPU_SMT_FORCE_DISABLED) {
 369                 enum cpuhp_smt_control old = cpu_smt_control;
 370
 371                 ret = cpuhp_smt_enable();
 372                 if (ret)
 373                         goto out;
 374                 ret = cpuhp_smt_disable(old);
 375                 if (ret)
 376                         goto out;
 377         }
 378 out:
 379         cpu_hotplug_disable();
 380         return ret;
 381 }