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/e820/api.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_table_firmware->nr_entries;
 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_table, &e820_table_firmware->entries, nr_e820_entries*sizeof(struct e820_entry));
 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         if (image->type == KEXEC_TYPE_CRASH) {
 226                 ret = crash_setup_memmap_entries(image, params);
 227                 if (ret)
 228                         return ret;
 229         } else
 230                 setup_e820_entries(params);
 231
 232         nr_e820_entries = params->e820_entries;
 233
 234         for (i = 0; i < nr_e820_entries; i++) {
 235                 if (params->e820_table[i].type != E820_TYPE_RAM)
 236                         continue;
 237                 start = params->e820_table[i].addr;
 238                 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
 239
 240                 if ((start <= 0x100000) && end > 0x100000) {
 241                         mem_k = (end >> 10) - (0x100000 >> 10);
 242                         params->screen_info.ext_mem_k = mem_k;
 243                         params->alt_mem_k = mem_k;
 244                         if (mem_k > 0xfc00)
 245                                 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
 246                         if (mem_k > 0xffffffff)
 247                                 params->alt_mem_k = 0xffffffff;
 248                 }
 249         }
 250
 251 #ifdef CONFIG_EFI
 252         /* Setup EFI state */
 253         setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
 254                         efi_setup_data_offset);
 255 #endif
 256
 257         /* Setup EDD info */
 258         memcpy(params->eddbuf, boot_params.eddbuf,
 259                                 EDDMAXNR * sizeof(struct edd_info));
 260         params->eddbuf_entries = boot_params.eddbuf_entries;
 261
 262         memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
 263                EDD_MBR_SIG_MAX * sizeof(unsigned int));
 264
 265         return ret;
 266 }
 267
 268 static int bzImage64_probe(const char *buf, unsigned long len)
 269 {
 270         int ret = -ENOEXEC;
 271         struct setup_header *header;
 272
 273         /* kernel should be at least two sectors long */
 274         if (len < 2 * 512) {
 275                 pr_err("File is too short to be a bzImage\n");
 276                 return ret;
 277         }
 278
 279         header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
 280         if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
 281                 pr_err("Not a bzImage\n");
 282                 return ret;
 283         }
 284
 285         if (header->boot_flag != 0xAA55) {
 286                 pr_err("No x86 boot sector present\n");
 287                 return ret;
 288         }
 289
 290         if (header->version < 0x020C) {
 291                 pr_err("Must be at least protocol version 2.12\n");
 292                 return ret;
 293         }
 294
 295         if (!(header->loadflags & LOADED_HIGH)) {
 296                 pr_err("zImage not a bzImage\n");
 297                 return ret;
 298         }
 299
 300         if (!(header->xloadflags & XLF_KERNEL_64)) {
 301                 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
 302                 return ret;
 303         }
 304
 305         if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
 306                 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
 307                 return ret;
 308         }
 309
 310         /*
 311          * Can't handle 32bit EFI as it does not allow loading kernel
 312          * above 4G. This should be handled by 32bit bzImage loader
 313          */
 314         if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
 315                 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
 316                 return ret;
 317         }
 318
 319         /* I've got a bzImage */
 320         pr_debug("It's a relocatable bzImage64\n");
 321         ret = 0;
 322
 323         return ret;
 324 }
 325
 326 static void *bzImage64_load(struct kimage *image, char *kernel,
 327                             unsigned long kernel_len, char *initrd,
 328                             unsigned long initrd_len, char *cmdline,
 329                             unsigned long cmdline_len)
 330 {
 331
 332         struct setup_header *header;
 333         int setup_sects, kern16_size, ret = 0;
 334         unsigned long setup_header_size, params_cmdline_sz;
 335         struct boot_params *params;
 336         unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
 337         unsigned long purgatory_load_addr;
 338         struct bzimage64_data *ldata;
 339         struct kexec_entry64_regs regs64;
 340         void *stack;
 341         unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
 342         unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
 343         struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
 344                                   .top_down = true };
 345
 346         header = (struct setup_header *)(kernel + setup_hdr_offset);
 347         setup_sects = header->setup_sects;
 348         if (setup_sects == 0)
 349                 setup_sects = 4;
 350
 351         kern16_size = (setup_sects + 1) * 512;
 352         if (kernel_len < kern16_size) {
 353                 pr_err("bzImage truncated\n");
 354                 return ERR_PTR(-ENOEXEC);
 355         }
 356
 357         if (cmdline_len > header->cmdline_size) {
 358                 pr_err("Kernel command line too long\n");
 359                 return ERR_PTR(-EINVAL);
 360         }
 361
 362         /*
 363          * In case of crash dump, we will append elfcorehdr=<addr> to
 364          * command line. Make sure it does not overflow
 365          */
 366         if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
 367                 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 368                 return ERR_PTR(-EINVAL);
 369         }
 370
 371         /* Allocate and load backup region */
 372         if (image->type == KEXEC_TYPE_CRASH) {
 373                 ret = crash_load_segments(image);
 374                 if (ret)
 375                         return ERR_PTR(ret);
 376         }
 377
 378         /*
 379          * Load purgatory. For 64bit entry point, purgatory  code can be
 380          * anywhere.
 381          */
 382         ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1,
 383                                    &purgatory_load_addr);
 384         if (ret) {
 385                 pr_err("Loading purgatory failed\n");
 386                 return ERR_PTR(ret);
 387         }
 388
 389         pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
 390
 391
 392         /*
 393          * Load Bootparams and cmdline and space for efi stuff.
 394          *
 395          * Allocate memory together for multiple data structures so
 396          * that they all can go in single area/segment and we don't
 397          * have to create separate segment for each. Keeps things
 398          * little bit simple
 399          */
 400         efi_map_sz = efi_get_runtime_map_size();
 401         efi_map_sz = ALIGN(efi_map_sz, 16);
 402         params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
 403                                 MAX_ELFCOREHDR_STR_LEN;
 404         params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
 405         kbuf.bufsz = params_cmdline_sz + efi_map_sz +
 406                                 sizeof(struct setup_data) +
 407                                 sizeof(struct efi_setup_data);
 408
 409         params = kzalloc(kbuf.bufsz, GFP_KERNEL);
 410         if (!params)
 411                 return ERR_PTR(-ENOMEM);
 412         efi_map_offset = params_cmdline_sz;
 413         efi_setup_data_offset = efi_map_offset + efi_map_sz;
 414
 415         /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
 416         setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
 417
 418         /* Is there a limit on setup header size? */
 419         memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
 420
 421         kbuf.buffer = params;
 422         kbuf.memsz = kbuf.bufsz;
 423         kbuf.buf_align = 16;
 424         kbuf.buf_min = MIN_BOOTPARAM_ADDR;
 425         ret = kexec_add_buffer(&kbuf);
 426         if (ret)
 427                 goto out_free_params;
 428         bootparam_load_addr = kbuf.mem;
 429         pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 430                  bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
 431
 432         /* Load kernel */
 433         kbuf.buffer = kernel + kern16_size;
 434         kbuf.bufsz =  kernel_len - kern16_size;
 435         kbuf.memsz = PAGE_ALIGN(header->init_size);
 436         kbuf.buf_align = header->kernel_alignment;
 437         kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
 438         ret = kexec_add_buffer(&kbuf);
 439         if (ret)
 440                 goto out_free_params;
 441         kernel_load_addr = kbuf.mem;
 442
 443         pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 444                  kernel_load_addr, kbuf.bufsz, kbuf.memsz);
 445
 446         /* Load initrd high */
 447         if (initrd) {
 448                 kbuf.buffer = initrd;
 449                 kbuf.bufsz = kbuf.memsz = initrd_len;
 450                 kbuf.buf_align = PAGE_SIZE;
 451                 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
 452                 ret = kexec_add_buffer(&kbuf);
 453                 if (ret)
 454                         goto out_free_params;
 455                 initrd_load_addr = kbuf.mem;
 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         return verify_pefile_signature(kernel, kernel_len,
 536                                        NULL,
 537                                        VERIFYING_KEXEC_PE_SIGNATURE);
 538 }
 539 #endif
 540
 541 struct kexec_file_ops kexec_bzImage64_ops = {
 542         .probe = bzImage64_probe,
 543         .load = bzImage64_load,
 544         .cleanup = bzImage64_cleanup,
 545 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
 546         .verify_sig = bzImage64_verify_sig,
 547 #endif
 548 };