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