arch/x86/kernel/kexec-bzimage64.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Kexec bzImage loader
   4  *
   5  * Copyright (C) 2014 Red Hat Inc.
   6  * Authors:
   7  *      Vivek Goyal <vgoyal@redhat.com>
   8  */
   9
  10 #define pr_fmt(fmt)     "kexec-bzImage64: " fmt
  11
  12 #include <linux/string.h>
  13 #include <linux/printk.h>
  14 #include <linux/errno.h>
  15 #include <linux/slab.h>
  16 #include <linux/kexec.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 #include <linux/efi.h>
  20 #include <linux/verification.h>
  21
  22 #include <asm/bootparam.h>
  23 #include <asm/setup.h>
  24 #include <asm/crash.h>
  25 #include <asm/efi.h>
  26 #include <asm/e820/api.h>
  27 #include <asm/kexec-bzimage64.h>
  28
  29 #define MAX_ELFCOREHDR_STR_LEN  30      /* elfcorehdr=0x<64bit-value> */
  30
  31 /*
  32  * Defines lowest physical address for various segments. Not sure where
  33  * exactly these limits came from. Current bzimage64 loader in kexec-tools
  34  * uses these so I am retaining it. It can be changed over time as we gain
  35  * more insight.
  36  */
  37 #define MIN_PURGATORY_ADDR      0x3000
  38 #define MIN_BOOTPARAM_ADDR      0x3000
  39 #define MIN_KERNEL_LOAD_ADDR    0x100000
  40 #define MIN_INITRD_LOAD_ADDR    0x1000000
  41
  42 /*
  43  * This is a place holder for all boot loader specific data structure which
  44  * gets allocated in one call but gets freed much later during cleanup
  45  * time. Right now there is only one field but it can grow as need be.
  46  */
  47 struct bzimage64_data {
  48         /*
  49          * Temporary buffer to hold bootparams buffer. This should be
  50          * freed once the bootparam segment has been loaded.
  51          */
  52         void *bootparams_buf;
  53 };
  54
  55 static int setup_initrd(struct boot_params *params,
  56                 unsigned long initrd_load_addr, unsigned long initrd_len)
  57 {
  58         params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
  59         params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
  60
  61         params->ext_ramdisk_image = initrd_load_addr >> 32;
  62         params->ext_ramdisk_size = initrd_len >> 32;
  63
  64         return 0;
  65 }
  66
  67 static int setup_cmdline(struct kimage *image, struct boot_params *params,
  68                          unsigned long bootparams_load_addr,
  69                          unsigned long cmdline_offset, char *cmdline,
  70                          unsigned long cmdline_len)
  71 {
  72         char *cmdline_ptr = ((char *)params) + cmdline_offset;
  73         unsigned long cmdline_ptr_phys, len = 0;
  74         uint32_t cmdline_low_32, cmdline_ext_32;
  75
  76         if (image->type == KEXEC_TYPE_CRASH) {
  77                 len = sprintf(cmdline_ptr,
  78                         "elfcorehdr=0x%lx ", image->elf_load_addr);
  79         }
  80         memcpy(cmdline_ptr + len, cmdline, cmdline_len);
  81         cmdline_len += len;
  82
  83         cmdline_ptr[cmdline_len - 1] = '\0';
  84
  85         pr_debug("Final command line is: %s\n", cmdline_ptr);
  86         cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
  87         cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
  88         cmdline_ext_32 = cmdline_ptr_phys >> 32;
  89
  90         params->hdr.cmd_line_ptr = cmdline_low_32;
  91         if (cmdline_ext_32)
  92                 params->ext_cmd_line_ptr = cmdline_ext_32;
  93
  94         return 0;
  95 }
  96
  97 static int setup_e820_entries(struct boot_params *params)
  98 {
  99         unsigned int nr_e820_entries;
 100
 101         nr_e820_entries = e820_table_kexec->nr_entries;
 102
 103         /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
 104         if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
 105                 nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;
 106
 107         params->e820_entries = nr_e820_entries;
 108         memcpy(&params->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));
 109
 110         return 0;
 111 }
 112
 113 #ifdef CONFIG_EFI
 114 static int setup_efi_info_memmap(struct boot_params *params,
 115                                   unsigned long params_load_addr,
 116                                   unsigned int efi_map_offset,
 117                                   unsigned int efi_map_sz)
 118 {
 119         void *efi_map = (void *)params + efi_map_offset;
 120         unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
 121         struct efi_info *ei = &params->efi_info;
 122
 123         if (!efi_map_sz)
 124                 return 0;
 125
 126         efi_runtime_map_copy(efi_map, efi_map_sz);
 127
 128         ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
 129         ei->efi_memmap_hi = efi_map_phys_addr >> 32;
 130         ei->efi_memmap_size = efi_map_sz;
 131
 132         return 0;
 133 }
 134
 135 static int
 136 prepare_add_efi_setup_data(struct boot_params *params,
 137                        unsigned long params_load_addr,
 138                        unsigned int efi_setup_data_offset)
 139 {
 140         unsigned long setup_data_phys;
 141         struct setup_data *sd = (void *)params + efi_setup_data_offset;
 142         struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
 143
 144         esd->fw_vendor = efi_fw_vendor;
 145         esd->tables = efi_config_table;
 146         esd->smbios = efi.smbios;
 147
 148         sd->type = SETUP_EFI;
 149         sd->len = sizeof(struct efi_setup_data);
 150
 151         /* Add setup data */
 152         setup_data_phys = params_load_addr + efi_setup_data_offset;
 153         sd->next = params->hdr.setup_data;
 154         params->hdr.setup_data = setup_data_phys;
 155
 156         return 0;
 157 }
 158
 159 static int
 160 setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 161                 unsigned int efi_map_offset, unsigned int efi_map_sz,
 162                 unsigned int efi_setup_data_offset)
 163 {
 164         struct efi_info *current_ei = &boot_params.efi_info;
 165         struct efi_info *ei = &params->efi_info;
 166
 167         if (!efi_enabled(EFI_RUNTIME_SERVICES))
 168                 return 0;
 169
 170         if (!current_ei->efi_memmap_size)
 171                 return 0;
 172
 173         params->secure_boot = boot_params.secure_boot;
 174         ei->efi_loader_signature = current_ei->efi_loader_signature;
 175         ei->efi_systab = current_ei->efi_systab;
 176         ei->efi_systab_hi = current_ei->efi_systab_hi;
 177
 178         ei->efi_memdesc_version = current_ei->efi_memdesc_version;
 179         ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
 180
 181         setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
 182                               efi_map_sz);
 183         prepare_add_efi_setup_data(params, params_load_addr,
 184                                    efi_setup_data_offset);
 185         return 0;
 186 }
 187 #endif /* CONFIG_EFI */
 188
 189 static int
 190 setup_boot_parameters(struct kimage *image, struct boot_params *params,
 191                       unsigned long params_load_addr,
 192                       unsigned int efi_map_offset, unsigned int efi_map_sz,
 193                       unsigned int efi_setup_data_offset)
 194 {
 195         unsigned int nr_e820_entries;
 196         unsigned long long mem_k, start, end;
 197         int i, ret = 0;
 198
 199         /* Get subarch from existing bootparams */
 200         params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 201
 202         /* Copying screen_info will do? */
 203         memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
 204
 205         /* Fill in memsize later */
 206         params->screen_info.ext_mem_k = 0;
 207         params->alt_mem_k = 0;
 208
 209         /* Always fill in RSDP: it is either 0 or a valid value */
 210         params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
 211
 212         /* Default APM info */
 213         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
 214
 215         /* Default drive info */
 216         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
 217         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
 218
 219         if (image->type == KEXEC_TYPE_CRASH) {
 220                 ret = crash_setup_memmap_entries(image, params);
 221                 if (ret)
 222                         return ret;
 223         } else
 224                 setup_e820_entries(params);
 225
 226         nr_e820_entries = params->e820_entries;
 227
 228         for (i = 0; i < nr_e820_entries; i++) {
 229                 if (params->e820_table[i].type != E820_TYPE_RAM)
 230                         continue;
 231                 start = params->e820_table[i].addr;
 232                 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
 233
 234                 if ((start <= 0x100000) && end > 0x100000) {
 235                         mem_k = (end >> 10) - (0x100000 >> 10);
 236                         params->screen_info.ext_mem_k = mem_k;
 237                         params->alt_mem_k = mem_k;
 238                         if (mem_k > 0xfc00)
 239                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
 240                         if (mem_k > 0xffffffff)
 241                                 params->alt_mem_k = 0xffffffff;
 242                 }
 243         }
 244
 245 #ifdef CONFIG_EFI
 246         /* Setup EFI state */
 247         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
 248                         efi_setup_data_offset);
 249 #endif
 250         /* Setup EDD info */
 251         memcpy(params->eddbuf, boot_params.eddbuf,
 252                                 EDDMAXNR * sizeof(struct edd_info));
 253         params->eddbuf_entries = boot_params.eddbuf_entries;
 254
 255         memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
 256                EDD_MBR_SIG_MAX * sizeof(unsigned int));
 257
 258         return ret;
 259 }
 260
 261 static int bzImage64_probe(const char *buf, unsigned long len)
 262 {
 263         int ret = -ENOEXEC;
 264         struct setup_header *header;
 265
 266         /* kernel should be at least two sectors long */
 267         if (len < 2 * 512) {
 268                 pr_err("File is too short to be a bzImage\n");
 269                 return ret;
 270         }
 271
 272         header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
 273         if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
 274                 pr_err("Not a bzImage\n");
 275                 return ret;
 276         }
 277
 278         if (header->boot_flag != 0xAA55) {
 279                 pr_err("No x86 boot sector present\n");
 280                 return ret;
 281         }
 282
 283         if (header->version < 0x020C) {
 284                 pr_err("Must be at least protocol version 2.12\n");
 285                 return ret;
 286         }
 287
 288         if (!(header->loadflags & LOADED_HIGH)) {
 289                 pr_err("zImage not a bzImage\n");
 290                 return ret;
 291         }
 292
 293         if (!(header->xloadflags & XLF_KERNEL_64)) {
 294                 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
 295                 return ret;
 296         }
 297
 298         if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
 299                 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
 300                 return ret;
 301         }
 302
 303         /*
 304          * Can't handle 32bit EFI as it does not allow loading kernel
 305          * above 4G. This should be handled by 32bit bzImage loader
 306          */
 307         if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
 308                 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
 309                 return ret;
 310         }
 311
 312         if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
 313                 pr_err("bzImage cannot handle 5-level paging mode.\n");
 314                 return ret;
 315         }
 316
 317         /* I've got a bzImage */
 318         pr_debug("It's a relocatable bzImage64\n");
 319         ret = 0;
 320
 321         return ret;
 322 }
 323
 324 static void *bzImage64_load(struct kimage *image, char *kernel,
 325                             unsigned long kernel_len, char *initrd,
 326                             unsigned long initrd_len, char *cmdline,
 327                             unsigned long cmdline_len)
 328 {
 329
 330         struct setup_header *header;
 331         int setup_sects, kern16_size, ret = 0;
 332         unsigned long setup_header_size, params_cmdline_sz;
 333         struct boot_params *params;
 334         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 335         struct bzimage64_data *ldata;
 336         struct kexec_entry64_regs regs64;
 337         void *stack;
 338         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 339         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 340         struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
 341                                   .top_down = true };
 342         struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
 343                                   .buf_max = ULONG_MAX, .top_down = true };
 344
 345         header = (struct setup_header *)(kernel + setup_hdr_offset);
 346         setup_sects = header->setup_sects;
 347         if (setup_sects == 0)
 348                 setup_sects = 4;
 349
 350         kern16_size = (setup_sects + 1) * 512;
 351         if (kernel_len < kern16_size) {
 352                 pr_err("bzImage truncated\n");
 353                 return ERR_PTR(-ENOEXEC);
 354         }
 355
 356         if (cmdline_len > header->cmdline_size) {
 357                 pr_err("Kernel command line too long\n");
 358                 return ERR_PTR(-EINVAL);
 359         }
 360
 361         /*
 362          * In case of crash dump, we will append elfcorehdr=<addr> to
 363          * command line. Make sure it does not overflow
 364          */
 365         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 366                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 367                 return ERR_PTR(-EINVAL);
 368         }
 369
 370         /* Allocate and load backup region */
 371         if (image->type == KEXEC_TYPE_CRASH) {
 372                 ret = crash_load_segments(image);
 373                 if (ret)
 374                         return ERR_PTR(ret);
 375         }
 376
 377         /*
 378          * Load purgatory. For 64bit entry point, purgatory  code can be
 379          * anywhere.
 380          */
 381         ret = kexec_load_purgatory(image, &pbuf);
 382         if (ret) {
 383                 pr_err("Loading purgatory failed\n");
 384                 return ERR_PTR(ret);
 385         }
 386
 387         pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
 388
 389
 390         /*
 391          * Load Bootparams and cmdline and space for efi stuff.
 392          *
 393          * Allocate memory together for multiple data structures so
 394          * that they all can go in single area/segment and we don't
 395          * have to create separate segment for each. Keeps things
 396          * little bit simple
 397          */
 398         efi_map_sz = efi_get_runtime_map_size();
 399         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 400                                 MAX_ELFCOREHDR_STR_LEN;
 401         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 402         kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
 403                                 sizeof(struct setup_data) +
 404                                 sizeof(struct efi_setup_data);
 405
 406         params = kzalloc(kbuf.bufsz, GFP_KERNEL);
 407         if (!params)
 408                 return ERR_PTR(-ENOMEM);
 409         efi_map_offset = params_cmdline_sz;
 410         efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
 411
 412         /* Copy setup header onto bootparams. Documentation/x86/boot.rst */
 413         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 414
 415         /* Is there a limit on setup header size? */
 416         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 417
 418         kbuf.buffer = params;
 419         kbuf.memsz = kbuf.bufsz;
 420         kbuf.buf_align = 16;
 421         kbuf.buf_min = MIN_BOOTPARAM_ADDR;
 422         ret = kexec_add_buffer(&kbuf);
 423         if (ret)
 424                 goto out_free_params;
 425         bootparam_load_addr = kbuf.mem;
 426         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 427                  bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
 428
 429         /* Load kernel */
 430         kbuf.buffer = kernel + kern16_size;
 431         kbuf.bufsz =  kernel_len - kern16_size;
 432         kbuf.memsz = PAGE_ALIGN(header->init_size);
 433         kbuf.buf_align = header->kernel_alignment;
 434         kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
 435         kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 436         ret = kexec_add_buffer(&kbuf);
 437         if (ret)
 438                 goto out_free_params;
 439         kernel_load_addr = kbuf.mem;
 440
 441         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 442                  kernel_load_addr, kbuf.bufsz, kbuf.memsz);
 443
 444         /* Load initrd high */
 445         if (initrd) {
 446                 kbuf.buffer = initrd;
 447                 kbuf.bufsz = kbuf.memsz = initrd_len;
 448                 kbuf.buf_align = PAGE_SIZE;
 449                 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
 450                 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 451                 ret = kexec_add_buffer(&kbuf);
 452                 if (ret)
 453                         goto out_free_params;
 454                 initrd_load_addr = kbuf.mem;
 455
 456                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 457                                 initrd_load_addr, initrd_len, initrd_len);
 458
 459                 setup_initrd(params, initrd_load_addr, initrd_len);
 460         }
 461
 462         setup_cmdline(image, params, bootparam_load_addr,
 463                       sizeof(struct boot_params), cmdline, cmdline_len);
 464
 465         /* bootloader info. Do we need a separate ID for kexec kernel loader? */
 466         params->hdr.type_of_loader = 0x0D << 4;
 467         params->hdr.loadflags = 0;
 468
 469         /* Setup purgatory regs for entry */
 470         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 471                                              sizeof(regs64), 1);
 472         if (ret)
 473                 goto out_free_params;
 474
 475         regs64.rbx = 0; /* Bootstrap Processor */
 476         regs64.rsi = bootparam_load_addr;
 477         regs64.rip = kernel_load_addr + 0x200;
 478         stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
 479         if (IS_ERR(stack)) {
 480                 pr_err("Could not find address of symbol stack_end\n");
 481                 ret = -EINVAL;
 482                 goto out_free_params;
 483         }
 484
 485         regs64.rsp = (unsigned long)stack;
 486         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 487                                              sizeof(regs64), 0);
 488         if (ret)
 489                 goto out_free_params;
 490
 491         ret = setup_boot_parameters(image, params, bootparam_load_addr,
 492                                     efi_map_offset, efi_map_sz,
 493                                     efi_setup_data_offset);
 494         if (ret)
 495                 goto out_free_params;
 496
 497         /* Allocate loader specific data */
 498         ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
 499         if (!ldata) {
 500                 ret = -ENOMEM;
 501                 goto out_free_params;
 502         }
 503
 504         /*
 505          * Store pointer to params so that it could be freed after loading
 506          * params segment has been loaded and contents have been copied
 507          * somewhere else.
 508          */
 509         ldata->bootparams_buf = params;
 510         return ldata;
 511
 512 out_free_params:
 513         kfree(params);
 514         return ERR_PTR(ret);
 515 }
 516
 517 /* This cleanup function is called after various segments have been loaded */
 518 static int bzImage64_cleanup(void *loader_data)
 519 {
 520         struct bzimage64_data *ldata = loader_data;
 521
 522         if (!ldata)
 523                 return 0;
 524
 525         kfree(ldata->bootparams_buf);
 526         ldata->bootparams_buf = NULL;
 527
 528         return 0;
 529 }
 530
 531 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 532 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 533 {
 534         int ret;
 535
 536         ret = verify_pefile_signature(kernel, kernel_len,
 537                                       VERIFY_USE_SECONDARY_KEYRING,
 538                                       VERIFYING_KEXEC_PE_SIGNATURE);
 539         if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
 540                 ret = verify_pefile_signature(kernel, kernel_len,
 541                                               VERIFY_USE_PLATFORM_KEYRING,
 542                                               VERIFYING_KEXEC_PE_SIGNATURE);
 543         }
 544         return ret;
 545 }
 546 #endif
 547
 548 const struct kexec_file_ops kexec_bzImage64_ops = {
 549         .probe = bzImage64_probe,
 550         .load = bzImage64_load,
 551         .cleanup = bzImage64_cleanup,
 552 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 553         .verify_sig = bzImage64_verify_sig,
 554 #endif
 555 };