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 = 0;
  76         uint32_t cmdline_low_32, cmdline_ext_32;
  77
  78         if (image->type == KEXEC_TYPE_CRASH) {
  79                 len = sprintf(cmdline_ptr,
  80                         "elfcorehdr=0x%lx ", image->arch.elf_load_addr);
  81         }
  82         memcpy(cmdline_ptr + len, cmdline, cmdline_len);
  83         cmdline_len += len;
  84
  85         cmdline_ptr[cmdline_len - 1] = '\0';
  86
  87         pr_debug("Final command line is: %s\n", cmdline_ptr);
  88         cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
  89         cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
  90         cmdline_ext_32 = cmdline_ptr_phys >> 32;
  91
  92         params->hdr.cmd_line_ptr = cmdline_low_32;
  93         if (cmdline_ext_32)
  94                 params->ext_cmd_line_ptr = cmdline_ext_32;
  95
  96         return 0;
  97 }
  98
  99 static int setup_e820_entries(struct boot_params *params)
 100 {
 101         unsigned int nr_e820_entries;
 102
 103         nr_e820_entries = e820_saved.nr_map;
 104
 105         /* TODO: Pass entries more than E820MAX in bootparams setup data */
 106         if (nr_e820_entries > E820MAX)
 107                 nr_e820_entries = E820MAX;
 108
 109         params->e820_entries = nr_e820_entries;
 110         memcpy(&params->e820_map, &e820_saved.map,
 111                nr_e820_entries * sizeof(struct e820entry));
 112
 113         return 0;
 114 }
 115
 116 #ifdef CONFIG_EFI
 117 static int setup_efi_info_memmap(struct boot_params *params,
 118                                   unsigned long params_load_addr,
 119                                   unsigned int efi_map_offset,
 120                                   unsigned int efi_map_sz)
 121 {
 122         void *efi_map = (void *)params + efi_map_offset;
 123         unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
 124         struct efi_info *ei = &params->efi_info;
 125
 126         if (!efi_map_sz)
 127                 return 0;
 128
 129         efi_runtime_map_copy(efi_map, efi_map_sz);
 130
 131         ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
 132         ei->efi_memmap_hi = efi_map_phys_addr >> 32;
 133         ei->efi_memmap_size = efi_map_sz;
 134
 135         return 0;
 136 }
 137
 138 static int
 139 prepare_add_efi_setup_data(struct boot_params *params,
 140                        unsigned long params_load_addr,
 141                        unsigned int efi_setup_data_offset)
 142 {
 143         unsigned long setup_data_phys;
 144         struct setup_data *sd = (void *)params + efi_setup_data_offset;
 145         struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
 146
 147         esd->fw_vendor = efi.fw_vendor;
 148         esd->runtime = efi.runtime;
 149         esd->tables = efi.config_table;
 150         esd->smbios = efi.smbios;
 151
 152         sd->type = SETUP_EFI;
 153         sd->len = sizeof(struct efi_setup_data);
 154
 155         /* Add setup data */
 156         setup_data_phys = params_load_addr + efi_setup_data_offset;
 157         sd->next = params->hdr.setup_data;
 158         params->hdr.setup_data = setup_data_phys;
 159
 160         return 0;
 161 }
 162
 163 static int
 164 setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 165                 unsigned int efi_map_offset, unsigned int efi_map_sz,
 166                 unsigned int efi_setup_data_offset)
 167 {
 168         struct efi_info *current_ei = &boot_params.efi_info;
 169         struct efi_info *ei = &params->efi_info;
 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         /* Default APM info */
 220         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
 221
 222         /* Default drive info */
 223         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
 224         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
 225
 226         /* Default sysdesc table */
 227         params->sys_desc_table.length = 0;
 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_map[i].type != E820_RAM)
 240                         continue;
 241                 start = params->e820_map[i].addr;
 242                 end = params->e820_map[i].addr + params->e820_map[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
 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 atleast 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         /* I've got a bzImage */
 324         pr_debug("It's a relocatable bzImage64\n");
 325         ret = 0;
 326
 327         return ret;
 328 }
 329
 330 static void *bzImage64_load(struct kimage *image, char *kernel,
 331                             unsigned long kernel_len, char *initrd,
 332                             unsigned long initrd_len, char *cmdline,
 333                             unsigned long cmdline_len)
 334 {
 335
 336         struct setup_header *header;
 337         int setup_sects, kern16_size, ret = 0;
 338         unsigned long setup_header_size, params_cmdline_sz, params_misc_sz;
 339         struct boot_params *params;
 340         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 341         unsigned long purgatory_load_addr;
 342         unsigned long kernel_bufsz, kernel_memsz, kernel_align;
 343         char *kernel_buf;
 344         struct bzimage64_data *ldata;
 345         struct kexec_entry64_regs regs64;
 346         void *stack;
 347         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 348         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 349
 350         header = (struct setup_header *)(kernel + setup_hdr_offset);
 351         setup_sects = header->setup_sects;
 352         if (setup_sects == 0)
 353                 setup_sects = 4;
 354
 355         kern16_size = (setup_sects + 1) * 512;
 356         if (kernel_len < kern16_size) {
 357                 pr_err("bzImage truncated\n");
 358                 return ERR_PTR(-ENOEXEC);
 359         }
 360
 361         if (cmdline_len > header->cmdline_size) {
 362                 pr_err("Kernel command line too long\n");
 363                 return ERR_PTR(-EINVAL);
 364         }
 365
 366         /*
 367          * In case of crash dump, we will append elfcorehdr=<addr> to
 368          * command line. Make sure it does not overflow
 369          */
 370         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 371                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 372                 return ERR_PTR(-EINVAL);
 373         }
 374
 375         /* Allocate and load backup region */
 376         if (image->type == KEXEC_TYPE_CRASH) {
 377                 ret = crash_load_segments(image);
 378                 if (ret)
 379                         return ERR_PTR(ret);
 380         }
 381
 382         /*
 383          * Load purgatory. For 64bit entry point, purgatory  code can be
 384          * anywhere.
 385          */
 386         ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
 387                                    &purgatory_load_addr);
 388         if (ret) {
 389                 pr_err("Loading purgatory failed\n");
 390                 return ERR_PTR(ret);
 391         }
 392
 393         pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
 394
 395
 396         /*
 397          * Load Bootparams and cmdline and space for efi stuff.
 398          *
 399          * Allocate memory together for multiple data structures so
 400          * that they all can go in single area/segment and we don't
 401          * have to create separate segment for each. Keeps things
 402          * little bit simple
 403          */
 404         efi_map_sz = efi_get_runtime_map_size();
 405         efi_map_sz = ALIGN(efi_map_sz, 16);
 406         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 407                                 MAX_ELFCOREHDR_STR_LEN;
 408         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 409         params_misc_sz = params_cmdline_sz + efi_map_sz +
 410                                 sizeof(struct setup_data) +
 411                                 sizeof(struct efi_setup_data);
 412
 413         params = kzalloc(params_misc_sz, GFP_KERNEL);
 414         if (!params)
 415                 return ERR_PTR(-ENOMEM);
 416         efi_map_offset = params_cmdline_sz;
 417         efi_setup_data_offset = efi_map_offset + efi_map_sz;
 418
 419         /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
 420         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 421
 422         /* Is there a limit on setup header size? */
 423         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 424
 425         ret = kexec_add_buffer(image, (char *)params, params_misc_sz,
 426                                params_misc_sz, 16, MIN_BOOTPARAM_ADDR,
 427                                ULONG_MAX, 1, &bootparam_load_addr);
 428         if (ret)
 429                 goto out_free_params;
 430         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 431                  bootparam_load_addr, params_misc_sz, params_misc_sz);
 432
 433         /* Load kernel */
 434         kernel_buf = kernel + kern16_size;
 435         kernel_bufsz =  kernel_len - kern16_size;
 436         kernel_memsz = PAGE_ALIGN(header->init_size);
 437         kernel_align = header->kernel_alignment;
 438
 439         ret = kexec_add_buffer(image, kernel_buf,
 440                                kernel_bufsz, kernel_memsz, kernel_align,
 441                                MIN_KERNEL_LOAD_ADDR, ULONG_MAX, 1,
 442                                &kernel_load_addr);
 443         if (ret)
 444                 goto out_free_params;
 445
 446         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 447                  kernel_load_addr, kernel_memsz, kernel_memsz);
 448
 449         /* Load initrd high */
 450         if (initrd) {
 451                 ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,
 452                                        PAGE_SIZE, MIN_INITRD_LOAD_ADDR,
 453                                        ULONG_MAX, 1, &initrd_load_addr);
 454                 if (ret)
 455                         goto out_free_params;
 456
 457                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 458                                 initrd_load_addr, initrd_len, initrd_len);
 459
 460                 setup_initrd(params, initrd_load_addr, initrd_len);
 461         }
 462
 463         setup_cmdline(image, params, bootparam_load_addr,
 464                       sizeof(struct boot_params), cmdline, cmdline_len);
 465
 466         /* bootloader info. Do we need a separate ID for kexec kernel loader? */
 467         params->hdr.type_of_loader = 0x0D << 4;
 468         params->hdr.loadflags = 0;
 469
 470         /* Setup purgatory regs for entry */
 471         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 472                                              sizeof(regs64), 1);
 473         if (ret)
 474                 goto out_free_params;
 475
 476         regs64.rbx = 0; /* Bootstrap Processor */
 477         regs64.rsi = bootparam_load_addr;
 478         regs64.rip = kernel_load_addr + 0x200;
 479         stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
 480         if (IS_ERR(stack)) {
 481                 pr_err("Could not find address of symbol stack_end\n");
 482                 ret = -EINVAL;
 483                 goto out_free_params;
 484         }
 485
 486         regs64.rsp = (unsigned long)stack;
 487         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 488                                              sizeof(regs64), 0);
 489         if (ret)
 490                 goto out_free_params;
 491
 492         ret = setup_boot_parameters(image, params, bootparam_load_addr,
 493                                     efi_map_offset, efi_map_sz,
 494                                     efi_setup_data_offset);
 495         if (ret)
 496                 goto out_free_params;
 497
 498         /* Allocate loader specific data */
 499         ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
 500         if (!ldata) {
 501                 ret = -ENOMEM;
 502                 goto out_free_params;
 503         }
 504
 505         /*
 506          * Store pointer to params so that it could be freed after loading
 507          * params segment has been loaded and contents have been copied
 508          * somewhere else.
 509          */
 510         ldata->bootparams_buf = params;
 511         return ldata;
 512
 513 out_free_params:
 514         kfree(params);
 515         return ERR_PTR(ret);
 516 }
 517
 518 /* This cleanup function is called after various segments have been loaded */
 519 static int bzImage64_cleanup(void *loader_data)
 520 {
 521         struct bzimage64_data *ldata = loader_data;
 522
 523         if (!ldata)
 524                 return 0;
 525
 526         kfree(ldata->bootparams_buf);
 527         ldata->bootparams_buf = NULL;
 528
 529         return 0;
 530 }
 531
 532 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 533 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 534 {
 535         bool trusted;
 536         int ret;
 537
 538         ret = verify_pefile_signature(kernel, kernel_len,
 539                                       system_trusted_keyring, &trusted);
 540         if (ret < 0)
 541                 return ret;
 542         if (!trusted)
 543                 return -EKEYREJECTED;
 544         return 0;
 545 }
 546 #endif
 547
 548 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 };