arch/x86/kernel/kexec-bzimage64.c

   1 /*
   2  * Kexec bzImage loader
   3  *
   4  * Copyright (C) 2014 Red Hat Inc.
   5  * Authors:
   6  *      Vivek Goyal <vgoyal@redhat.com>
   7  *
   8  * This source code is licensed under the GNU General Public License,
   9  * Version 2.  See the file COPYING for more details.
  10  */
  11
  12 #define pr_fmt(fmt)     "kexec-bzImage64: " fmt
  13
  14 #include <linux/string.h>
  15 #include <linux/printk.h>
  16 #include <linux/errno.h>
  17 #include <linux/slab.h>
  18 #include <linux/kexec.h>
  19 #include <linux/kernel.h>
  20 #include <linux/mm.h>
  21 #include <linux/efi.h>
  22 #include <linux/verify_pefile.h>
  23 #include <keys/system_keyring.h>
  24
  25 #include <asm/bootparam.h>
  26 #include <asm/setup.h>
  27 #include <asm/crash.h>
  28 #include <asm/efi.h>
  29 #include <asm/kexec-bzimage64.h>
  30
  31 #define MAX_ELFCOREHDR_STR_LEN  30      /* elfcorehdr=0x<64bit-value> */
  32
  33 /*
  34  * Defines lowest physical address for various segments. Not sure where
  35  * exactly these limits came from. Current bzimage64 loader in kexec-tools
  36  * uses these so I am retaining it. It can be changed over time as we gain
  37  * more insight.
  38  */
  39 #define MIN_PURGATORY_ADDR      0x3000
  40 #define MIN_BOOTPARAM_ADDR      0x3000
  41 #define MIN_KERNEL_LOAD_ADDR    0x100000
  42 #define MIN_INITRD_LOAD_ADDR    0x1000000
  43
  44 /*
  45  * This is a place holder for all boot loader specific data structure which
  46  * gets allocated in one call but gets freed much later during cleanup
  47  * time. Right now there is only one field but it can grow as need be.
  48  */
  49 struct bzimage64_data {
  50         /*
  51          * Temporary buffer to hold bootparams buffer. This should be
  52          * freed once the bootparam segment has been loaded.
  53          */
  54         void *bootparams_buf;
  55 };
  56
  57 static int setup_initrd(struct boot_params *params,
  58                 unsigned long initrd_load_addr, unsigned long initrd_len)
  59 {
  60         params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
  61         params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
  62
  63         params->ext_ramdisk_image = initrd_load_addr >> 32;
  64         params->ext_ramdisk_size = initrd_len >> 32;
  65
  66         return 0;
  67 }
  68
  69 static int setup_cmdline(struct kimage *image, struct boot_params *params,
  70                          unsigned long bootparams_load_addr,
  71                          unsigned long cmdline_offset, char *cmdline,
  72                          unsigned long cmdline_len)
  73 {
  74         char *cmdline_ptr = ((char *)params) + cmdline_offset;
  75         unsigned long cmdline_ptr_phys, len;
  76         uint32_t cmdline_low_32, cmdline_ext_32;
  77
  78         memcpy(cmdline_ptr, cmdline, cmdline_len);
  79         if (image->type == KEXEC_TYPE_CRASH) {
  80                 len = sprintf(cmdline_ptr + cmdline_len - 1,
  81                         " elfcorehdr=0x%lx", image->arch.elf_load_addr);
  82                 cmdline_len += len;
  83         }
  84         cmdline_ptr[cmdline_len - 1] = '\0';
  85
  86         pr_debug("Final command line is: %s\n", cmdline_ptr);
  87         cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
  88         cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
  89         cmdline_ext_32 = cmdline_ptr_phys >> 32;
  90
  91         params->hdr.cmd_line_ptr = cmdline_low_32;
  92         if (cmdline_ext_32)
  93                 params->ext_cmd_line_ptr = cmdline_ext_32;
  94
  95         return 0;
  96 }
  97
  98 static int setup_e820_entries(struct boot_params *params)
  99 {
 100         unsigned int nr_e820_entries;
 101
 102         nr_e820_entries = e820_saved.nr_map;
 103
 104         /* TODO: Pass entries more than E820MAX in bootparams setup data */
 105         if (nr_e820_entries > E820MAX)
 106                 nr_e820_entries = E820MAX;
 107
 108         params->e820_entries = nr_e820_entries;
 109         memcpy(&params->e820_map, &e820_saved.map,
 110                nr_e820_entries * sizeof(struct e820entry));
 111
 112         return 0;
 113 }
 114
 115 #ifdef CONFIG_EFI
 116 static int setup_efi_info_memmap(struct boot_params *params,
 117                                   unsigned long params_load_addr,
 118                                   unsigned int efi_map_offset,
 119                                   unsigned int efi_map_sz)
 120 {
 121         void *efi_map = (void *)params + efi_map_offset;
 122         unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
 123         struct efi_info *ei = &params->efi_info;
 124
 125         if (!efi_map_sz)
 126                 return 0;
 127
 128         efi_runtime_map_copy(efi_map, efi_map_sz);
 129
 130         ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
 131         ei->efi_memmap_hi = efi_map_phys_addr >> 32;
 132         ei->efi_memmap_size = efi_map_sz;
 133
 134         return 0;
 135 }
 136
 137 static int
 138 prepare_add_efi_setup_data(struct boot_params *params,
 139                        unsigned long params_load_addr,
 140                        unsigned int efi_setup_data_offset)
 141 {
 142         unsigned long setup_data_phys;
 143         struct setup_data *sd = (void *)params + efi_setup_data_offset;
 144         struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
 145
 146         esd->fw_vendor = efi.fw_vendor;
 147         esd->runtime = efi.runtime;
 148         esd->tables = efi.config_table;
 149         esd->smbios = efi.smbios;
 150
 151         sd->type = SETUP_EFI;
 152         sd->len = sizeof(struct efi_setup_data);
 153
 154         /* Add setup data */
 155         setup_data_phys = params_load_addr + efi_setup_data_offset;
 156         sd->next = params->hdr.setup_data;
 157         params->hdr.setup_data = setup_data_phys;
 158
 159         return 0;
 160 }
 161
 162 static int
 163 setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 164                 unsigned int efi_map_offset, unsigned int efi_map_sz,
 165                 unsigned int efi_setup_data_offset)
 166 {
 167         struct efi_info *current_ei = &boot_params.efi_info;
 168         struct efi_info *ei = &params->efi_info;
 169
 170         if (!current_ei->efi_memmap_size)
 171                 return 0;
 172
 173         /*
 174          * If 1:1 mapping is not enabled, second kernel can not setup EFI
 175          * and use EFI run time services. User space will have to pass
 176          * acpi_rsdp=<addr> on kernel command line to make second kernel boot
 177          * without efi.
 178          */
 179         if (efi_enabled(EFI_OLD_MEMMAP))
 180                 return 0;
 181
 182         ei->efi_loader_signature = current_ei->efi_loader_signature;
 183         ei->efi_systab = current_ei->efi_systab;
 184         ei->efi_systab_hi = current_ei->efi_systab_hi;
 185
 186         ei->efi_memdesc_version = current_ei->efi_memdesc_version;
 187         ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
 188
 189         setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
 190                               efi_map_sz);
 191         prepare_add_efi_setup_data(params, params_load_addr,
 192                                    efi_setup_data_offset);
 193         return 0;
 194 }
 195 #endif /* CONFIG_EFI */
 196
 197 static int
 198 setup_boot_parameters(struct kimage *image, struct boot_params *params,
 199                       unsigned long params_load_addr,
 200                       unsigned int efi_map_offset, unsigned int efi_map_sz,
 201                       unsigned int efi_setup_data_offset)
 202 {
 203         unsigned int nr_e820_entries;
 204         unsigned long long mem_k, start, end;
 205         int i, ret = 0;
 206
 207         /* Get subarch from existing bootparams */
 208         params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 209
 210         /* Copying screen_info will do? */
 211         memcpy(&params->screen_info, &boot_params.screen_info,
 212                                 sizeof(struct screen_info));
 213
 214         /* Fill in memsize later */
 215         params->screen_info.ext_mem_k = 0;
 216         params->alt_mem_k = 0;
 217
 218         /* Default APM info */
 219         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
 220
 221         /* Default drive info */
 222         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
 223         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
 224
 225         /* Default sysdesc table */
 226         params->sys_desc_table.length = 0;
 227
 228         if (image->type == KEXEC_TYPE_CRASH) {
 229                 ret = crash_setup_memmap_entries(image, params);
 230                 if (ret)
 231                         return ret;
 232         } else
 233                 setup_e820_entries(params);
 234
 235         nr_e820_entries = params->e820_entries;
 236
 237         for (i = 0; i < nr_e820_entries; i++) {
 238                 if (params->e820_map[i].type != E820_RAM)
 239                         continue;
 240                 start = params->e820_map[i].addr;
 241                 end = params->e820_map[i].addr + params->e820_map[i].size - 1;
 242
 243                 if ((start <= 0x100000) && end > 0x100000) {
 244                         mem_k = (end >> 10) - (0x100000 >> 10);
 245                         params->screen_info.ext_mem_k = mem_k;
 246                         params->alt_mem_k = mem_k;
 247                         if (mem_k > 0xfc00)
 248                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
 249                         if (mem_k > 0xffffffff)
 250                                 params->alt_mem_k = 0xffffffff;
 251                 }
 252         }
 253
 254 #ifdef CONFIG_EFI
 255         /* Setup EFI state */
 256         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
 257                         efi_setup_data_offset);
 258 #endif
 259
 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 atleast 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         /* I've got a bzImage */
 323         pr_debug("It's a relocatable bzImage64\n");
 324         ret = 0;
 325
 326         return ret;
 327 }
 328
 329 static void *bzImage64_load(struct kimage *image, char *kernel,
 330                             unsigned long kernel_len, char *initrd,
 331                             unsigned long initrd_len, char *cmdline,
 332                             unsigned long cmdline_len)
 333 {
 334
 335         struct setup_header *header;
 336         int setup_sects, kern16_size, ret = 0;
 337         unsigned long setup_header_size, params_cmdline_sz, params_misc_sz;
 338         struct boot_params *params;
 339         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 340         unsigned long purgatory_load_addr;
 341         unsigned long kernel_bufsz, kernel_memsz, kernel_align;
 342         char *kernel_buf;
 343         struct bzimage64_data *ldata;
 344         struct kexec_entry64_regs regs64;
 345         void *stack;
 346         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 347         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 348
 349         header = (struct setup_header *)(kernel + setup_hdr_offset);
 350         setup_sects = header->setup_sects;
 351         if (setup_sects == 0)
 352                 setup_sects = 4;
 353
 354         kern16_size = (setup_sects + 1) * 512;
 355         if (kernel_len < kern16_size) {
 356                 pr_err("bzImage truncated\n");
 357                 return ERR_PTR(-ENOEXEC);
 358         }
 359
 360         if (cmdline_len > header->cmdline_size) {
 361                 pr_err("Kernel command line too long\n");
 362                 return ERR_PTR(-EINVAL);
 363         }
 364
 365         /*
 366          * In case of crash dump, we will append elfcorehdr=<addr> to
 367          * command line. Make sure it does not overflow
 368          */
 369         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 370                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 371                 return ERR_PTR(-EINVAL);
 372         }
 373
 374         /* Allocate and load backup region */
 375         if (image->type == KEXEC_TYPE_CRASH) {
 376                 ret = crash_load_segments(image);
 377                 if (ret)
 378                         return ERR_PTR(ret);
 379         }
 380
 381         /*
 382          * Load purgatory. For 64bit entry point, purgatory  code can be
 383          * anywhere.
 384          */
 385         ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
 386                                    &purgatory_load_addr);
 387         if (ret) {
 388                 pr_err("Loading purgatory failed\n");
 389                 return ERR_PTR(ret);
 390         }
 391
 392         pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
 393
 394
 395         /*
 396          * Load Bootparams and cmdline and space for efi stuff.
 397          *
 398          * Allocate memory together for multiple data structures so
 399          * that they all can go in single area/segment and we don't
 400          * have to create separate segment for each. Keeps things
 401          * little bit simple
 402          */
 403         efi_map_sz = efi_get_runtime_map_size();
 404         efi_map_sz = ALIGN(efi_map_sz, 16);
 405         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 406                                 MAX_ELFCOREHDR_STR_LEN;
 407         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 408         params_misc_sz = params_cmdline_sz + efi_map_sz +
 409                                 sizeof(struct setup_data) +
 410                                 sizeof(struct efi_setup_data);
 411
 412         params = kzalloc(params_misc_sz, GFP_KERNEL);
 413         if (!params)
 414                 return ERR_PTR(-ENOMEM);
 415         efi_map_offset = params_cmdline_sz;
 416         efi_setup_data_offset = efi_map_offset + efi_map_sz;
 417
 418         /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
 419         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 420
 421         /* Is there a limit on setup header size? */
 422         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 423
 424         ret = kexec_add_buffer(image, (char *)params, params_misc_sz,
 425                                params_misc_sz, 16, MIN_BOOTPARAM_ADDR,
 426                                ULONG_MAX, 1, &bootparam_load_addr);
 427         if (ret)
 428                 goto out_free_params;
 429         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 430                  bootparam_load_addr, params_misc_sz, params_misc_sz);
 431
 432         /* Load kernel */
 433         kernel_buf = kernel + kern16_size;
 434         kernel_bufsz =  kernel_len - kern16_size;
 435         kernel_memsz = PAGE_ALIGN(header->init_size);
 436         kernel_align = header->kernel_alignment;
 437
 438         ret = kexec_add_buffer(image, kernel_buf,
 439                                kernel_bufsz, kernel_memsz, kernel_align,
 440                                MIN_KERNEL_LOAD_ADDR, ULONG_MAX, 1,
 441                                &kernel_load_addr);
 442         if (ret)
 443                 goto out_free_params;
 444
 445         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 446                  kernel_load_addr, kernel_memsz, kernel_memsz);
 447
 448         /* Load initrd high */
 449         if (initrd) {
 450                 ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,
 451                                        PAGE_SIZE, MIN_INITRD_LOAD_ADDR,
 452                                        ULONG_MAX, 1, &initrd_load_addr);
 453                 if (ret)
 454                         goto out_free_params;
 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         bool trusted;
 535         int ret;
 536
 537         ret = verify_pefile_signature(kernel, kernel_len,
 538                                       system_trusted_keyring, &trusted);
 539         if (ret < 0)
 540                 return ret;
 541         if (!trusted)
 542                 return -EKEYREJECTED;
 543         return 0;
 544 }
 545 #endif
 546
 547 struct kexec_file_ops kexec_bzImage64_ops = {
 548         .probe = bzImage64_probe,
 549         .load = bzImage64_load,
 550         .cleanup = bzImage64_cleanup,
 551 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 552         .verify_sig = bzImage64_verify_sig,
 553 #endif
 554 };