root/arch/x86/kernel/kexec-bzimage64.c

DEFINITIONS

1. setup_initrd
2. setup_cmdline
3. setup_e820_entries
4. setup_efi_info_memmap
5. prepare_add_efi_setup_data
6. setup_efi_state
7. setup_boot_parameters
8. bzImage64_probe
9. bzImage64_load
10. bzImage64_cleanup
11. bzImage64_verify_sig

   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->arch.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->runtime = efi.runtime;
 146         esd->tables = efi.config_table;
 147         esd->smbios = efi.smbios;
 148 
 149         sd->type = SETUP_EFI;
 150         sd->len = sizeof(struct efi_setup_data);
 151 
 152         /* Add setup data */
 153         setup_data_phys = params_load_addr + efi_setup_data_offset;
 154         sd->next = params->hdr.setup_data;
 155         params->hdr.setup_data = setup_data_phys;
 156 
 157         return 0;
 158 }
 159 
 160 static int
 161 setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 162                 unsigned int efi_map_offset, unsigned int efi_map_sz,
 163                 unsigned int efi_setup_data_offset)
 164 {
 165         struct efi_info *current_ei = &boot_params.efi_info;
 166         struct efi_info *ei = &params->efi_info;
 167 
 168         if (!efi_enabled(EFI_RUNTIME_SERVICES))
 169                 return 0;
 170 
 171         if (!current_ei->efi_memmap_size)
 172                 return 0;
 173 
 174         /*
 175          * If 1:1 mapping is not enabled, second kernel can not setup EFI
 176          * and use EFI run time services. User space will have to pass
 177          * acpi_rsdp=<addr> on kernel command line to make second kernel boot
 178          * without efi.
 179          */
 180         if (efi_enabled(EFI_OLD_MEMMAP))
 181                 return 0;
 182 
 183         params->secure_boot = boot_params.secure_boot;
 184         ei->efi_loader_signature = current_ei->efi_loader_signature;
 185         ei->efi_systab = current_ei->efi_systab;
 186         ei->efi_systab_hi = current_ei->efi_systab_hi;
 187 
 188         ei->efi_memdesc_version = current_ei->efi_memdesc_version;
 189         ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
 190 
 191         setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
 192                               efi_map_sz);
 193         prepare_add_efi_setup_data(params, params_load_addr,
 194                                    efi_setup_data_offset);
 195         return 0;
 196 }
 197 #endif /* CONFIG_EFI */
 198 
 199 static int
 200 setup_boot_parameters(struct kimage *image, struct boot_params *params,
 201                       unsigned long params_load_addr,
 202                       unsigned int efi_map_offset, unsigned int efi_map_sz,
 203                       unsigned int efi_setup_data_offset)
 204 {
 205         unsigned int nr_e820_entries;
 206         unsigned long long mem_k, start, end;
 207         int i, ret = 0;
 208 
 209         /* Get subarch from existing bootparams */
 210         params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 211 
 212         /* Copying screen_info will do? */
 213         memcpy(&params->screen_info, &boot_params.screen_info,
 214                                 sizeof(struct screen_info));
 215 
 216         /* Fill in memsize later */
 217         params->screen_info.ext_mem_k = 0;
 218         params->alt_mem_k = 0;
 219 
 220         /* Always fill in RSDP: it is either 0 or a valid value */
 221         params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
 222 
 223         /* Default APM info */
 224         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
 225 
 226         /* Default drive info */
 227         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
 228         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
 229 
 230         if (image->type == KEXEC_TYPE_CRASH) {
 231                 ret = crash_setup_memmap_entries(image, params);
 232                 if (ret)
 233                         return ret;
 234         } else
 235                 setup_e820_entries(params);
 236 
 237         nr_e820_entries = params->e820_entries;
 238 
 239         for (i = 0; i < nr_e820_entries; i++) {
 240                 if (params->e820_table[i].type != E820_TYPE_RAM)
 241                         continue;
 242                 start = params->e820_table[i].addr;
 243                 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
 244 
 245                 if ((start <= 0x100000) && end > 0x100000) {
 246                         mem_k = (end >> 10) - (0x100000 >> 10);
 247                         params->screen_info.ext_mem_k = mem_k;
 248                         params->alt_mem_k = mem_k;
 249                         if (mem_k > 0xfc00)
 250                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
 251                         if (mem_k > 0xffffffff)
 252                                 params->alt_mem_k = 0xffffffff;
 253                 }
 254         }
 255 
 256 #ifdef CONFIG_EFI
 257         /* Setup EFI state */
 258         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
 259                         efi_setup_data_offset);
 260 #endif
 261         /* Setup EDD info */
 262         memcpy(params->eddbuf, boot_params.eddbuf,
 263                                 EDDMAXNR * sizeof(struct edd_info));
 264         params->eddbuf_entries = boot_params.eddbuf_entries;
 265 
 266         memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
 267                EDD_MBR_SIG_MAX * sizeof(unsigned int));
 268 
 269         return ret;
 270 }
 271 
 272 static int bzImage64_probe(const char *buf, unsigned long len)
 273 {
 274         int ret = -ENOEXEC;
 275         struct setup_header *header;
 276 
 277         /* kernel should be at least two sectors long */
 278         if (len < 2 * 512) {
 279                 pr_err("File is too short to be a bzImage\n");
 280                 return ret;
 281         }
 282 
 283         header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
 284         if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
 285                 pr_err("Not a bzImage\n");
 286                 return ret;
 287         }
 288 
 289         if (header->boot_flag != 0xAA55) {
 290                 pr_err("No x86 boot sector present\n");
 291                 return ret;
 292         }
 293 
 294         if (header->version < 0x020C) {
 295                 pr_err("Must be at least protocol version 2.12\n");
 296                 return ret;
 297         }
 298 
 299         if (!(header->loadflags & LOADED_HIGH)) {
 300                 pr_err("zImage not a bzImage\n");
 301                 return ret;
 302         }
 303 
 304         if (!(header->xloadflags & XLF_KERNEL_64)) {
 305                 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
 306                 return ret;
 307         }
 308 
 309         if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
 310                 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
 311                 return ret;
 312         }
 313 
 314         /*
 315          * Can't handle 32bit EFI as it does not allow loading kernel
 316          * above 4G. This should be handled by 32bit bzImage loader
 317          */
 318         if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
 319                 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
 320                 return ret;
 321         }
 322 
 323         if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
 324                 pr_err("bzImage cannot handle 5-level paging mode.\n");
 325                 return ret;
 326         }
 327 
 328         /* I've got a bzImage */
 329         pr_debug("It's a relocatable bzImage64\n");
 330         ret = 0;
 331 
 332         return ret;
 333 }
 334 
 335 static void *bzImage64_load(struct kimage *image, char *kernel,
 336                             unsigned long kernel_len, char *initrd,
 337                             unsigned long initrd_len, char *cmdline,
 338                             unsigned long cmdline_len)
 339 {
 340 
 341         struct setup_header *header;
 342         int setup_sects, kern16_size, ret = 0;
 343         unsigned long setup_header_size, params_cmdline_sz;
 344         struct boot_params *params;
 345         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 346         struct bzimage64_data *ldata;
 347         struct kexec_entry64_regs regs64;
 348         void *stack;
 349         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 350         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 351         struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
 352                                   .top_down = true };
 353         struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
 354                                   .buf_max = ULONG_MAX, .top_down = true };
 355 
 356         header = (struct setup_header *)(kernel + setup_hdr_offset);
 357         setup_sects = header->setup_sects;
 358         if (setup_sects == 0)
 359                 setup_sects = 4;
 360 
 361         kern16_size = (setup_sects + 1) * 512;
 362         if (kernel_len < kern16_size) {
 363                 pr_err("bzImage truncated\n");
 364                 return ERR_PTR(-ENOEXEC);
 365         }
 366 
 367         if (cmdline_len > header->cmdline_size) {
 368                 pr_err("Kernel command line too long\n");
 369                 return ERR_PTR(-EINVAL);
 370         }
 371 
 372         /*
 373          * In case of crash dump, we will append elfcorehdr=<addr> to
 374          * command line. Make sure it does not overflow
 375          */
 376         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 377                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 378                 return ERR_PTR(-EINVAL);
 379         }
 380 
 381         /* Allocate and load backup region */
 382         if (image->type == KEXEC_TYPE_CRASH) {
 383                 ret = crash_load_segments(image);
 384                 if (ret)
 385                         return ERR_PTR(ret);
 386         }
 387 
 388         /*
 389          * Load purgatory. For 64bit entry point, purgatory  code can be
 390          * anywhere.
 391          */
 392         ret = kexec_load_purgatory(image, &pbuf);
 393         if (ret) {
 394                 pr_err("Loading purgatory failed\n");
 395                 return ERR_PTR(ret);
 396         }
 397 
 398         pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
 399 
 400 
 401         /*
 402          * Load Bootparams and cmdline and space for efi stuff.
 403          *
 404          * Allocate memory together for multiple data structures so
 405          * that they all can go in single area/segment and we don't
 406          * have to create separate segment for each. Keeps things
 407          * little bit simple
 408          */
 409         efi_map_sz = efi_get_runtime_map_size();
 410         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 411                                 MAX_ELFCOREHDR_STR_LEN;
 412         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 413         kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
 414                                 sizeof(struct setup_data) +
 415                                 sizeof(struct efi_setup_data);
 416 
 417         params = kzalloc(kbuf.bufsz, GFP_KERNEL);
 418         if (!params)
 419                 return ERR_PTR(-ENOMEM);
 420         efi_map_offset = params_cmdline_sz;
 421         efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
 422 
 423         /* Copy setup header onto bootparams. Documentation/x86/boot.rst */
 424         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 425 
 426         /* Is there a limit on setup header size? */
 427         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 428 
 429         kbuf.buffer = params;
 430         kbuf.memsz = kbuf.bufsz;
 431         kbuf.buf_align = 16;
 432         kbuf.buf_min = MIN_BOOTPARAM_ADDR;
 433         ret = kexec_add_buffer(&kbuf);
 434         if (ret)
 435                 goto out_free_params;
 436         bootparam_load_addr = kbuf.mem;
 437         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 438                  bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
 439 
 440         /* Load kernel */
 441         kbuf.buffer = kernel + kern16_size;
 442         kbuf.bufsz =  kernel_len - kern16_size;
 443         kbuf.memsz = PAGE_ALIGN(header->init_size);
 444         kbuf.buf_align = header->kernel_alignment;
 445         kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
 446         kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 447         ret = kexec_add_buffer(&kbuf);
 448         if (ret)
 449                 goto out_free_params;
 450         kernel_load_addr = kbuf.mem;
 451 
 452         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 453                  kernel_load_addr, kbuf.bufsz, kbuf.memsz);
 454 
 455         /* Load initrd high */
 456         if (initrd) {
 457                 kbuf.buffer = initrd;
 458                 kbuf.bufsz = kbuf.memsz = initrd_len;
 459                 kbuf.buf_align = PAGE_SIZE;
 460                 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
 461                 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 462                 ret = kexec_add_buffer(&kbuf);
 463                 if (ret)
 464                         goto out_free_params;
 465                 initrd_load_addr = kbuf.mem;
 466 
 467                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 468                                 initrd_load_addr, initrd_len, initrd_len);
 469 
 470                 setup_initrd(params, initrd_load_addr, initrd_len);
 471         }
 472 
 473         setup_cmdline(image, params, bootparam_load_addr,
 474                       sizeof(struct boot_params), cmdline, cmdline_len);
 475 
 476         /* bootloader info. Do we need a separate ID for kexec kernel loader? */
 477         params->hdr.type_of_loader = 0x0D << 4;
 478         params->hdr.loadflags = 0;
 479 
 480         /* Setup purgatory regs for entry */
 481         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 482                                              sizeof(regs64), 1);
 483         if (ret)
 484                 goto out_free_params;
 485 
 486         regs64.rbx = 0; /* Bootstrap Processor */
 487         regs64.rsi = bootparam_load_addr;
 488         regs64.rip = kernel_load_addr + 0x200;
 489         stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
 490         if (IS_ERR(stack)) {
 491                 pr_err("Could not find address of symbol stack_end\n");
 492                 ret = -EINVAL;
 493                 goto out_free_params;
 494         }
 495 
 496         regs64.rsp = (unsigned long)stack;
 497         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 498                                              sizeof(regs64), 0);
 499         if (ret)
 500                 goto out_free_params;
 501 
 502         ret = setup_boot_parameters(image, params, bootparam_load_addr,
 503                                     efi_map_offset, efi_map_sz,
 504                                     efi_setup_data_offset);
 505         if (ret)
 506                 goto out_free_params;
 507 
 508         /* Allocate loader specific data */
 509         ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
 510         if (!ldata) {
 511                 ret = -ENOMEM;
 512                 goto out_free_params;
 513         }
 514 
 515         /*
 516          * Store pointer to params so that it could be freed after loading
 517          * params segment has been loaded and contents have been copied
 518          * somewhere else.
 519          */
 520         ldata->bootparams_buf = params;
 521         return ldata;
 522 
 523 out_free_params:
 524         kfree(params);
 525         return ERR_PTR(ret);
 526 }
 527 
 528 /* This cleanup function is called after various segments have been loaded */
 529 static int bzImage64_cleanup(void *loader_data)
 530 {
 531         struct bzimage64_data *ldata = loader_data;
 532 
 533         if (!ldata)
 534                 return 0;
 535 
 536         kfree(ldata->bootparams_buf);
 537         ldata->bootparams_buf = NULL;
 538 
 539         return 0;
 540 }
 541 
 542 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 543 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 544 {
 545         int ret;
 546 
 547         ret = verify_pefile_signature(kernel, kernel_len,
 548                                       VERIFY_USE_SECONDARY_KEYRING,
 549                                       VERIFYING_KEXEC_PE_SIGNATURE);
 550         if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
 551                 ret = verify_pefile_signature(kernel, kernel_len,
 552                                               VERIFY_USE_PLATFORM_KEYRING,
 553                                               VERIFYING_KEXEC_PE_SIGNATURE);
 554         }
 555         return ret;
 556 }
 557 #endif
 558 
 559 const struct kexec_file_ops kexec_bzImage64_ops = {
 560         .probe = bzImage64_probe,
 561         .load = bzImage64_load,
 562         .cleanup = bzImage64_cleanup,
 563 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 564         .verify_sig = bzImage64_verify_sig,
 565 #endif
 566 };