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/verification.h>
  23
  24 #include <asm/bootparam.h>
  25 #include <asm/setup.h>
  26 #include <asm/crash.h>
  27 #include <asm/efi.h>
  28 #include <asm/kexec-bzimage64.h>
  29
  30 #define MAX_ELFCOREHDR_STR_LEN  30      /* elfcorehdr=0x<64bit-value> */
  31
  32 /*
  33  * Defines lowest physical address for various segments. Not sure where
  34  * exactly these limits came from. Current bzimage64 loader in kexec-tools
  35  * uses these so I am retaining it. It can be changed over time as we gain
  36  * more insight.
  37  */
  38 #define MIN_PURGATORY_ADDR      0x3000
  39 #define MIN_BOOTPARAM_ADDR      0x3000
  40 #define MIN_KERNEL_LOAD_ADDR    0x100000
  41 #define MIN_INITRD_LOAD_ADDR    0x1000000
  42
  43 /*
  44  * This is a place holder for all boot loader specific data structure which
  45  * gets allocated in one call but gets freed much later during cleanup
  46  * time. Right now there is only one field but it can grow as need be.
  47  */
  48 struct bzimage64_data {
  49         /*
  50          * Temporary buffer to hold bootparams buffer. This should be
  51          * freed once the bootparam segment has been loaded.
  52          */
  53         void *bootparams_buf;
  54 };
  55
  56 static int setup_initrd(struct boot_params *params,
  57                 unsigned long initrd_load_addr, unsigned long initrd_len)
  58 {
  59         params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
  60         params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
  61
  62         params->ext_ramdisk_image = initrd_load_addr >> 32;
  63         params->ext_ramdisk_size = initrd_len >> 32;
  64
  65         return 0;
  66 }
  67
  68 static int setup_cmdline(struct kimage *image, struct boot_params *params,
  69                          unsigned long bootparams_load_addr,
  70                          unsigned long cmdline_offset, char *cmdline,
  71                          unsigned long cmdline_len)
  72 {
  73         char *cmdline_ptr = ((char *)params) + cmdline_offset;
  74         unsigned long cmdline_ptr_phys, len = 0;
  75         uint32_t cmdline_low_32, cmdline_ext_32;
  76
  77         if (image->type == KEXEC_TYPE_CRASH) {
  78                 len = sprintf(cmdline_ptr,
  79                         "elfcorehdr=0x%lx ", image->arch.elf_load_addr);
  80         }
  81         memcpy(cmdline_ptr + len, cmdline, cmdline_len);
  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 (!efi_enabled(EFI_RUNTIME_SERVICES))
 171                 return 0;
 172
 173         if (!current_ei->efi_memmap_size)
 174                 return 0;
 175
 176         /*
 177          * If 1:1 mapping is not enabled, second kernel can not setup EFI
 178          * and use EFI run time services. User space will have to pass
 179          * acpi_rsdp=<addr> on kernel command line to make second kernel boot
 180          * without efi.
 181          */
 182         if (efi_enabled(EFI_OLD_MEMMAP))
 183                 return 0;
 184
 185         ei->efi_loader_signature = current_ei->efi_loader_signature;
 186         ei->efi_systab = current_ei->efi_systab;
 187         ei->efi_systab_hi = current_ei->efi_systab_hi;
 188
 189         ei->efi_memdesc_version = current_ei->efi_memdesc_version;
 190         ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
 191
 192         setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
 193                               efi_map_sz);
 194         prepare_add_efi_setup_data(params, params_load_addr,
 195                                    efi_setup_data_offset);
 196         return 0;
 197 }
 198 #endif /* CONFIG_EFI */
 199
 200 static int
 201 setup_boot_parameters(struct kimage *image, struct boot_params *params,
 202                       unsigned long params_load_addr,
 203                       unsigned int efi_map_offset, unsigned int efi_map_sz,
 204                       unsigned int efi_setup_data_offset)
 205 {
 206         unsigned int nr_e820_entries;
 207         unsigned long long mem_k, start, end;
 208         int i, ret = 0;
 209
 210         /* Get subarch from existing bootparams */
 211         params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
 212
 213         /* Copying screen_info will do? */
 214         memcpy(&params->screen_info, &screen_info, 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         /* Default APM info */
 221         memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
 222
 223         /* Default drive info */
 224         memset(&params->hd0_info, 0, sizeof(params->hd0_info));
 225         memset(&params->hd1_info, 0, sizeof(params->hd1_info));
 226
 227         if (image->type == KEXEC_TYPE_CRASH) {
 228                 ret = crash_setup_memmap_entries(image, params);
 229                 if (ret)
 230                         return ret;
 231         } else
 232                 setup_e820_entries(params);
 233
 234         nr_e820_entries = params->e820_entries;
 235
 236         for (i = 0; i < nr_e820_entries; i++) {
 237                 if (params->e820_map[i].type != E820_RAM)
 238                         continue;
 239                 start = params->e820_map[i].addr;
 240                 end = params->e820_map[i].addr + params->e820_map[i].size - 1;
 241
 242                 if ((start <= 0x100000) && end > 0x100000) {
 243                         mem_k = (end >> 10) - (0x100000 >> 10);
 244                         params->screen_info.ext_mem_k = mem_k;
 245                         params->alt_mem_k = mem_k;
 246                         if (mem_k > 0xfc00)
 247                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
 248                         if (mem_k > 0xffffffff)
 249                                 params->alt_mem_k = 0xffffffff;
 250                 }
 251         }
 252
 253 #ifdef CONFIG_EFI
 254         /* Setup EFI state */
 255         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
 256                         efi_setup_data_offset);
 257 #endif
 258
 259         /* Setup EDD info */
 260         memcpy(params->eddbuf, boot_params.eddbuf,
 261                                 EDDMAXNR * sizeof(struct edd_info));
 262         params->eddbuf_entries = boot_params.eddbuf_entries;
 263
 264         memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
 265                EDD_MBR_SIG_MAX * sizeof(unsigned int));
 266
 267         return ret;
 268 }
 269
 270 static int bzImage64_probe(const char *buf, unsigned long len)
 271 {
 272         int ret = -ENOEXEC;
 273         struct setup_header *header;
 274
 275         /* kernel should be at least two sectors long */
 276         if (len < 2 * 512) {
 277                 pr_err("File is too short to be a bzImage\n");
 278                 return ret;
 279         }
 280
 281         header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
 282         if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
 283                 pr_err("Not a bzImage\n");
 284                 return ret;
 285         }
 286
 287         if (header->boot_flag != 0xAA55) {
 288                 pr_err("No x86 boot sector present\n");
 289                 return ret;
 290         }
 291
 292         if (header->version < 0x020C) {
 293                 pr_err("Must be at least protocol version 2.12\n");
 294                 return ret;
 295         }
 296
 297         if (!(header->loadflags & LOADED_HIGH)) {
 298                 pr_err("zImage not a bzImage\n");
 299                 return ret;
 300         }
 301
 302         if (!(header->xloadflags & XLF_KERNEL_64)) {
 303                 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
 304                 return ret;
 305         }
 306
 307         if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
 308                 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
 309                 return ret;
 310         }
 311
 312         /*
 313          * Can't handle 32bit EFI as it does not allow loading kernel
 314          * above 4G. This should be handled by 32bit bzImage loader
 315          */
 316         if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
 317                 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
 318                 return ret;
 319         }
 320
 321         /* I've got a bzImage */
 322         pr_debug("It's a relocatable bzImage64\n");
 323         ret = 0;
 324
 325         return ret;
 326 }
 327
 328 static void *bzImage64_load(struct kimage *image, char *kernel,
 329                             unsigned long kernel_len, char *initrd,
 330                             unsigned long initrd_len, char *cmdline,
 331                             unsigned long cmdline_len)
 332 {
 333
 334         struct setup_header *header;
 335         int setup_sects, kern16_size, ret = 0;
 336         unsigned long setup_header_size, params_cmdline_sz, params_misc_sz;
 337         struct boot_params *params;
 338         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 339         unsigned long purgatory_load_addr;
 340         unsigned long kernel_bufsz, kernel_memsz, kernel_align;
 341         char *kernel_buf;
 342         struct bzimage64_data *ldata;
 343         struct kexec_entry64_regs regs64;
 344         void *stack;
 345         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 346         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 347
 348         header = (struct setup_header *)(kernel + setup_hdr_offset);
 349         setup_sects = header->setup_sects;
 350         if (setup_sects == 0)
 351                 setup_sects = 4;
 352
 353         kern16_size = (setup_sects + 1) * 512;
 354         if (kernel_len < kern16_size) {
 355                 pr_err("bzImage truncated\n");
 356                 return ERR_PTR(-ENOEXEC);
 357         }
 358
 359         if (cmdline_len > header->cmdline_size) {
 360                 pr_err("Kernel command line too long\n");
 361                 return ERR_PTR(-EINVAL);
 362         }
 363
 364         /*
 365          * In case of crash dump, we will append elfcorehdr=<addr> to
 366          * command line. Make sure it does not overflow
 367          */
 368         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 369                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 370                 return ERR_PTR(-EINVAL);
 371         }
 372
 373         /* Allocate and load backup region */
 374         if (image->type == KEXEC_TYPE_CRASH) {
 375                 ret = crash_load_segments(image);
 376                 if (ret)
 377                         return ERR_PTR(ret);
 378         }
 379
 380         /*
 381          * Load purgatory. For 64bit entry point, purgatory  code can be
 382          * anywhere.
 383          */
 384         ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
 385                                    &purgatory_load_addr);
 386         if (ret) {
 387                 pr_err("Loading purgatory failed\n");
 388                 return ERR_PTR(ret);
 389         }
 390
 391         pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
 392
 393
 394         /*
 395          * Load Bootparams and cmdline and space for efi stuff.
 396          *
 397          * Allocate memory together for multiple data structures so
 398          * that they all can go in single area/segment and we don't
 399          * have to create separate segment for each. Keeps things
 400          * little bit simple
 401          */
 402         efi_map_sz = efi_get_runtime_map_size();
 403         efi_map_sz = ALIGN(efi_map_sz, 16);
 404         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 405                                 MAX_ELFCOREHDR_STR_LEN;
 406         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 407         params_misc_sz = params_cmdline_sz + efi_map_sz +
 408                                 sizeof(struct setup_data) +
 409                                 sizeof(struct efi_setup_data);
 410
 411         params = kzalloc(params_misc_sz, GFP_KERNEL);
 412         if (!params)
 413                 return ERR_PTR(-ENOMEM);
 414         efi_map_offset = params_cmdline_sz;
 415         efi_setup_data_offset = efi_map_offset + efi_map_sz;
 416
 417         /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
 418         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 419
 420         /* Is there a limit on setup header size? */
 421         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 422
 423         ret = kexec_add_buffer(image, (char *)params, params_misc_sz,
 424                                params_misc_sz, 16, MIN_BOOTPARAM_ADDR,
 425                                ULONG_MAX, 1, &bootparam_load_addr);
 426         if (ret)
 427                 goto out_free_params;
 428         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 429                  bootparam_load_addr, params_misc_sz, params_misc_sz);
 430
 431         /* Load kernel */
 432         kernel_buf = kernel + kern16_size;
 433         kernel_bufsz =  kernel_len - kern16_size;
 434         kernel_memsz = PAGE_ALIGN(header->init_size);
 435         kernel_align = header->kernel_alignment;
 436
 437         ret = kexec_add_buffer(image, kernel_buf,
 438                                kernel_bufsz, kernel_memsz, kernel_align,
 439                                MIN_KERNEL_LOAD_ADDR, ULONG_MAX, 1,
 440                                &kernel_load_addr);
 441         if (ret)
 442                 goto out_free_params;
 443
 444         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 445                  kernel_load_addr, kernel_memsz, kernel_memsz);
 446
 447         /* Load initrd high */
 448         if (initrd) {
 449                 ret = kexec_add_buffer(image, initrd, initrd_len, initrd_len,
 450                                        PAGE_SIZE, MIN_INITRD_LOAD_ADDR,
 451                                        ULONG_MAX, 1, &initrd_load_addr);
 452                 if (ret)
 453                         goto out_free_params;
 454
 455                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 456                                 initrd_load_addr, initrd_len, initrd_len);
 457
 458                 setup_initrd(params, initrd_load_addr, initrd_len);
 459         }
 460
 461         setup_cmdline(image, params, bootparam_load_addr,
 462                       sizeof(struct boot_params), cmdline, cmdline_len);
 463
 464         /* bootloader info. Do we need a separate ID for kexec kernel loader? */
 465         params->hdr.type_of_loader = 0x0D << 4;
 466         params->hdr.loadflags = 0;
 467
 468         /* Setup purgatory regs for entry */
 469         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 470                                              sizeof(regs64), 1);
 471         if (ret)
 472                 goto out_free_params;
 473
 474         regs64.rbx = 0; /* Bootstrap Processor */
 475         regs64.rsi = bootparam_load_addr;
 476         regs64.rip = kernel_load_addr + 0x200;
 477         stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
 478         if (IS_ERR(stack)) {
 479                 pr_err("Could not find address of symbol stack_end\n");
 480                 ret = -EINVAL;
 481                 goto out_free_params;
 482         }
 483
 484         regs64.rsp = (unsigned long)stack;
 485         ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
 486                                              sizeof(regs64), 0);
 487         if (ret)
 488                 goto out_free_params;
 489
 490         ret = setup_boot_parameters(image, params, bootparam_load_addr,
 491                                     efi_map_offset, efi_map_sz,
 492                                     efi_setup_data_offset);
 493         if (ret)
 494                 goto out_free_params;
 495
 496         /* Allocate loader specific data */
 497         ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
 498         if (!ldata) {
 499                 ret = -ENOMEM;
 500                 goto out_free_params;
 501         }
 502
 503         /*
 504          * Store pointer to params so that it could be freed after loading
 505          * params segment has been loaded and contents have been copied
 506          * somewhere else.
 507          */
 508         ldata->bootparams_buf = params;
 509         return ldata;
 510
 511 out_free_params:
 512         kfree(params);
 513         return ERR_PTR(ret);
 514 }
 515
 516 /* This cleanup function is called after various segments have been loaded */
 517 static int bzImage64_cleanup(void *loader_data)
 518 {
 519         struct bzimage64_data *ldata = loader_data;
 520
 521         if (!ldata)
 522                 return 0;
 523
 524         kfree(ldata->bootparams_buf);
 525         ldata->bootparams_buf = NULL;
 526
 527         return 0;
 528 }
 529
 530 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 531 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 532 {
 533         return verify_pefile_signature(kernel, kernel_len,
 534                                        VERIFY_USE_SECONDARY_KEYRING,
 535                                        VERIFYING_KEXEC_PE_SIGNATURE);
 536 }
 537 #endif
 538
 539 struct kexec_file_ops kexec_bzImage64_ops = {
 540         .probe = bzImage64_probe,
 541         .load = bzImage64_load,
 542         .cleanup = bzImage64_cleanup,
 543 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 544         .verify_sig = bzImage64_verify_sig,
 545 #endif
 546 };