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/random.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(¶ms->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry)); 109 110 return 0; 111 } 112 113 enum { RNG_SEED_LENGTH = 32 }; 114 115 static void 116 setup_rng_seed(struct boot_params *params, unsigned long params_load_addr, 117 unsigned int rng_seed_setup_data_offset) 118 { 119 struct setup_data *sd = (void *)params + rng_seed_setup_data_offset; 120 unsigned long setup_data_phys; 121 122 if (!rng_is_initialized()) 123 return; 124 125 sd->type = SETUP_RNG_SEED; 126 sd->len = RNG_SEED_LENGTH; 127 get_random_bytes(sd->data, RNG_SEED_LENGTH); 128 setup_data_phys = params_load_addr + rng_seed_setup_data_offset; 129 sd->next = params->hdr.setup_data; 130 params->hdr.setup_data = setup_data_phys; 131 } 132 133 #ifdef CONFIG_EFI 134 static int setup_efi_info_memmap(struct boot_params *params, 135 unsigned long params_load_addr, 136 unsigned int efi_map_offset, 137 unsigned int efi_map_sz) 138 { 139 void *efi_map = (void *)params + efi_map_offset; 140 unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset; 141 struct efi_info *ei = ¶ms->efi_info; 142 143 if (!efi_map_sz) 144 return 0; 145 146 efi_runtime_map_copy(efi_map, efi_map_sz); 147 148 ei->efi_memmap = efi_map_phys_addr & 0xffffffff; 149 ei->efi_memmap_hi = efi_map_phys_addr >> 32; 150 ei->efi_memmap_size = efi_map_sz; 151 152 return 0; 153 } 154 155 static int 156 prepare_add_efi_setup_data(struct boot_params *params, 157 unsigned long params_load_addr, 158 unsigned int efi_setup_data_offset) 159 { 160 unsigned long setup_data_phys; 161 struct setup_data *sd = (void *)params + efi_setup_data_offset; 162 struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data); 163 164 esd->fw_vendor = efi_fw_vendor; 165 esd->tables = efi_config_table; 166 esd->smbios = efi.smbios; 167 168 sd->type = SETUP_EFI; 169 sd->len = sizeof(struct efi_setup_data); 170 171 /* Add setup data */ 172 setup_data_phys = params_load_addr + efi_setup_data_offset; 173 sd->next = params->hdr.setup_data; 174 params->hdr.setup_data = setup_data_phys; 175 176 return 0; 177 } 178 179 static int 180 setup_efi_state(struct boot_params *params, unsigned long params_load_addr, 181 unsigned int efi_map_offset, unsigned int efi_map_sz, 182 unsigned int efi_setup_data_offset) 183 { 184 struct efi_info *current_ei = &boot_params.efi_info; 185 struct efi_info *ei = ¶ms->efi_info; 186 187 if (!efi_enabled(EFI_RUNTIME_SERVICES)) 188 return 0; 189 190 if (!current_ei->efi_memmap_size) 191 return 0; 192 193 params->secure_boot = boot_params.secure_boot; 194 ei->efi_loader_signature = current_ei->efi_loader_signature; 195 ei->efi_systab = current_ei->efi_systab; 196 ei->efi_systab_hi = current_ei->efi_systab_hi; 197 198 ei->efi_memdesc_version = current_ei->efi_memdesc_version; 199 ei->efi_memdesc_size = efi_get_runtime_map_desc_size(); 200 201 setup_efi_info_memmap(params, params_load_addr, efi_map_offset, 202 efi_map_sz); 203 prepare_add_efi_setup_data(params, params_load_addr, 204 efi_setup_data_offset); 205 return 0; 206 } 207 #endif /* CONFIG_EFI */ 208 209 static void 210 setup_ima_state(const struct kimage *image, struct boot_params *params, 211 unsigned long params_load_addr, 212 unsigned int ima_setup_data_offset) 213 { 214 #ifdef CONFIG_IMA_KEXEC 215 struct setup_data *sd = (void *)params + ima_setup_data_offset; 216 unsigned long setup_data_phys; 217 struct ima_setup_data *ima; 218 219 if (!image->ima_buffer_size) 220 return; 221 222 sd->type = SETUP_IMA; 223 sd->len = sizeof(*ima); 224 225 ima = (void *)sd + sizeof(struct setup_data); 226 ima->addr = image->ima_buffer_addr; 227 ima->size = image->ima_buffer_size; 228 229 /* Add setup data */ 230 setup_data_phys = params_load_addr + ima_setup_data_offset; 231 sd->next = params->hdr.setup_data; 232 params->hdr.setup_data = setup_data_phys; 233 #endif /* CONFIG_IMA_KEXEC */ 234 } 235 236 static int 237 setup_boot_parameters(struct kimage *image, struct boot_params *params, 238 unsigned long params_load_addr, 239 unsigned int efi_map_offset, unsigned int efi_map_sz, 240 unsigned int setup_data_offset) 241 { 242 unsigned int nr_e820_entries; 243 unsigned long long mem_k, start, end; 244 int i, ret = 0; 245 246 /* Get subarch from existing bootparams */ 247 params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch; 248 249 /* Copying screen_info will do? */ 250 memcpy(¶ms->screen_info, &screen_info, sizeof(struct screen_info)); 251 252 /* Fill in memsize later */ 253 params->screen_info.ext_mem_k = 0; 254 params->alt_mem_k = 0; 255 256 /* Always fill in RSDP: it is either 0 or a valid value */ 257 params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr; 258 259 /* Default APM info */ 260 memset(¶ms->apm_bios_info, 0, sizeof(params->apm_bios_info)); 261 262 /* Default drive info */ 263 memset(¶ms->hd0_info, 0, sizeof(params->hd0_info)); 264 memset(¶ms->hd1_info, 0, sizeof(params->hd1_info)); 265 266 if (image->type == KEXEC_TYPE_CRASH) { 267 ret = crash_setup_memmap_entries(image, params); 268 if (ret) 269 return ret; 270 } else 271 setup_e820_entries(params); 272 273 nr_e820_entries = params->e820_entries; 274 275 for (i = 0; i < nr_e820_entries; i++) { 276 if (params->e820_table[i].type != E820_TYPE_RAM) 277 continue; 278 start = params->e820_table[i].addr; 279 end = params->e820_table[i].addr + params->e820_table[i].size - 1; 280 281 if ((start <= 0x100000) && end > 0x100000) { 282 mem_k = (end >> 10) - (0x100000 >> 10); 283 params->screen_info.ext_mem_k = mem_k; 284 params->alt_mem_k = mem_k; 285 if (mem_k > 0xfc00) 286 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/ 287 if (mem_k > 0xffffffff) 288 params->alt_mem_k = 0xffffffff; 289 } 290 } 291 292 #ifdef CONFIG_EFI 293 /* Setup EFI state */ 294 setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz, 295 setup_data_offset); 296 setup_data_offset += sizeof(struct setup_data) + 297 sizeof(struct efi_setup_data); 298 #endif 299 300 if (IS_ENABLED(CONFIG_IMA_KEXEC)) { 301 /* Setup IMA log buffer state */ 302 setup_ima_state(image, params, params_load_addr, 303 setup_data_offset); 304 setup_data_offset += sizeof(struct setup_data) + 305 sizeof(struct ima_setup_data); 306 } 307 308 /* Setup RNG seed */ 309 setup_rng_seed(params, params_load_addr, setup_data_offset); 310 311 /* Setup EDD info */ 312 memcpy(params->eddbuf, boot_params.eddbuf, 313 EDDMAXNR * sizeof(struct edd_info)); 314 params->eddbuf_entries = boot_params.eddbuf_entries; 315 316 memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer, 317 EDD_MBR_SIG_MAX * sizeof(unsigned int)); 318 319 return ret; 320 } 321 322 static int bzImage64_probe(const char *buf, unsigned long len) 323 { 324 int ret = -ENOEXEC; 325 struct setup_header *header; 326 327 /* kernel should be at least two sectors long */ 328 if (len < 2 * 512) { 329 pr_err("File is too short to be a bzImage\n"); 330 return ret; 331 } 332 333 header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr)); 334 if (memcmp((char *)&header->header, "HdrS", 4) != 0) { 335 pr_err("Not a bzImage\n"); 336 return ret; 337 } 338 339 if (header->boot_flag != 0xAA55) { 340 pr_err("No x86 boot sector present\n"); 341 return ret; 342 } 343 344 if (header->version < 0x020C) { 345 pr_err("Must be at least protocol version 2.12\n"); 346 return ret; 347 } 348 349 if (!(header->loadflags & LOADED_HIGH)) { 350 pr_err("zImage not a bzImage\n"); 351 return ret; 352 } 353 354 if (!(header->xloadflags & XLF_KERNEL_64)) { 355 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n"); 356 return ret; 357 } 358 359 if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) { 360 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n"); 361 return ret; 362 } 363 364 /* 365 * Can't handle 32bit EFI as it does not allow loading kernel 366 * above 4G. This should be handled by 32bit bzImage loader 367 */ 368 if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) { 369 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n"); 370 return ret; 371 } 372 373 if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) { 374 pr_err("bzImage cannot handle 5-level paging mode.\n"); 375 return ret; 376 } 377 378 /* I've got a bzImage */ 379 pr_debug("It's a relocatable bzImage64\n"); 380 ret = 0; 381 382 return ret; 383 } 384 385 static void *bzImage64_load(struct kimage *image, char *kernel, 386 unsigned long kernel_len, char *initrd, 387 unsigned long initrd_len, char *cmdline, 388 unsigned long cmdline_len) 389 { 390 391 struct setup_header *header; 392 int setup_sects, kern16_size, ret = 0; 393 unsigned long setup_header_size, params_cmdline_sz; 394 struct boot_params *params; 395 unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr; 396 struct bzimage64_data *ldata; 397 struct kexec_entry64_regs regs64; 398 void *stack; 399 unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr); 400 unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset; 401 struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX, 402 .top_down = true }; 403 struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR, 404 .buf_max = ULONG_MAX, .top_down = true }; 405 406 header = (struct setup_header *)(kernel + setup_hdr_offset); 407 setup_sects = header->setup_sects; 408 if (setup_sects == 0) 409 setup_sects = 4; 410 411 kern16_size = (setup_sects + 1) * 512; 412 if (kernel_len < kern16_size) { 413 pr_err("bzImage truncated\n"); 414 return ERR_PTR(-ENOEXEC); 415 } 416 417 if (cmdline_len > header->cmdline_size) { 418 pr_err("Kernel command line too long\n"); 419 return ERR_PTR(-EINVAL); 420 } 421 422 /* 423 * In case of crash dump, we will append elfcorehdr=<addr> to 424 * command line. Make sure it does not overflow 425 */ 426 if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) { 427 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n"); 428 return ERR_PTR(-EINVAL); 429 } 430 431 /* Allocate and load backup region */ 432 if (image->type == KEXEC_TYPE_CRASH) { 433 ret = crash_load_segments(image); 434 if (ret) 435 return ERR_PTR(ret); 436 } 437 438 /* 439 * Load purgatory. For 64bit entry point, purgatory code can be 440 * anywhere. 441 */ 442 ret = kexec_load_purgatory(image, &pbuf); 443 if (ret) { 444 pr_err("Loading purgatory failed\n"); 445 return ERR_PTR(ret); 446 } 447 448 pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem); 449 450 451 /* 452 * Load Bootparams and cmdline and space for efi stuff. 453 * 454 * Allocate memory together for multiple data structures so 455 * that they all can go in single area/segment and we don't 456 * have to create separate segment for each. Keeps things 457 * little bit simple 458 */ 459 efi_map_sz = efi_get_runtime_map_size(); 460 params_cmdline_sz = sizeof(struct boot_params) + cmdline_len + 461 MAX_ELFCOREHDR_STR_LEN; 462 params_cmdline_sz = ALIGN(params_cmdline_sz, 16); 463 kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) + 464 sizeof(struct setup_data) + 465 sizeof(struct efi_setup_data) + 466 sizeof(struct setup_data) + 467 RNG_SEED_LENGTH; 468 469 if (IS_ENABLED(CONFIG_IMA_KEXEC)) 470 kbuf.bufsz += sizeof(struct setup_data) + 471 sizeof(struct ima_setup_data); 472 473 params = kzalloc(kbuf.bufsz, GFP_KERNEL); 474 if (!params) 475 return ERR_PTR(-ENOMEM); 476 efi_map_offset = params_cmdline_sz; 477 efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16); 478 479 /* Copy setup header onto bootparams. Documentation/x86/boot.rst */ 480 setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset; 481 482 /* Is there a limit on setup header size? */ 483 memcpy(¶ms->hdr, (kernel + setup_hdr_offset), setup_header_size); 484 485 kbuf.buffer = params; 486 kbuf.memsz = kbuf.bufsz; 487 kbuf.buf_align = 16; 488 kbuf.buf_min = MIN_BOOTPARAM_ADDR; 489 ret = kexec_add_buffer(&kbuf); 490 if (ret) 491 goto out_free_params; 492 bootparam_load_addr = kbuf.mem; 493 pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 494 bootparam_load_addr, kbuf.bufsz, kbuf.bufsz); 495 496 /* Load kernel */ 497 kbuf.buffer = kernel + kern16_size; 498 kbuf.bufsz = kernel_len - kern16_size; 499 kbuf.memsz = PAGE_ALIGN(header->init_size); 500 kbuf.buf_align = header->kernel_alignment; 501 kbuf.buf_min = MIN_KERNEL_LOAD_ADDR; 502 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 503 ret = kexec_add_buffer(&kbuf); 504 if (ret) 505 goto out_free_params; 506 kernel_load_addr = kbuf.mem; 507 508 pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 509 kernel_load_addr, kbuf.bufsz, kbuf.memsz); 510 511 /* Load initrd high */ 512 if (initrd) { 513 kbuf.buffer = initrd; 514 kbuf.bufsz = kbuf.memsz = initrd_len; 515 kbuf.buf_align = PAGE_SIZE; 516 kbuf.buf_min = MIN_INITRD_LOAD_ADDR; 517 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 518 ret = kexec_add_buffer(&kbuf); 519 if (ret) 520 goto out_free_params; 521 initrd_load_addr = kbuf.mem; 522 523 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 524 initrd_load_addr, initrd_len, initrd_len); 525 526 setup_initrd(params, initrd_load_addr, initrd_len); 527 } 528 529 setup_cmdline(image, params, bootparam_load_addr, 530 sizeof(struct boot_params), cmdline, cmdline_len); 531 532 /* bootloader info. Do we need a separate ID for kexec kernel loader? */ 533 params->hdr.type_of_loader = 0x0D << 4; 534 params->hdr.loadflags = 0; 535 536 /* Setup purgatory regs for entry */ 537 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64, 538 sizeof(regs64), 1); 539 if (ret) 540 goto out_free_params; 541 542 regs64.rbx = 0; /* Bootstrap Processor */ 543 regs64.rsi = bootparam_load_addr; 544 regs64.rip = kernel_load_addr + 0x200; 545 stack = kexec_purgatory_get_symbol_addr(image, "stack_end"); 546 if (IS_ERR(stack)) { 547 pr_err("Could not find address of symbol stack_end\n"); 548 ret = -EINVAL; 549 goto out_free_params; 550 } 551 552 regs64.rsp = (unsigned long)stack; 553 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64, 554 sizeof(regs64), 0); 555 if (ret) 556 goto out_free_params; 557 558 ret = setup_boot_parameters(image, params, bootparam_load_addr, 559 efi_map_offset, efi_map_sz, 560 efi_setup_data_offset); 561 if (ret) 562 goto out_free_params; 563 564 /* Allocate loader specific data */ 565 ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL); 566 if (!ldata) { 567 ret = -ENOMEM; 568 goto out_free_params; 569 } 570 571 /* 572 * Store pointer to params so that it could be freed after loading 573 * params segment has been loaded and contents have been copied 574 * somewhere else. 575 */ 576 ldata->bootparams_buf = params; 577 return ldata; 578 579 out_free_params: 580 kfree(params); 581 return ERR_PTR(ret); 582 } 583 584 /* This cleanup function is called after various segments have been loaded */ 585 static int bzImage64_cleanup(void *loader_data) 586 { 587 struct bzimage64_data *ldata = loader_data; 588 589 if (!ldata) 590 return 0; 591 592 kfree(ldata->bootparams_buf); 593 ldata->bootparams_buf = NULL; 594 595 return 0; 596 } 597 598 const struct kexec_file_ops kexec_bzImage64_ops = { 599 .probe = bzImage64_probe, 600 .load = bzImage64_load, 601 .cleanup = bzImage64_cleanup, 602 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG 603 .verify_sig = kexec_kernel_verify_pe_sig, 604 #endif 605 }; 606