kexec-bzimage64.c 15 KB

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  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. #define pr_fmt(fmt) "kexec-bzImage64: " fmt
  10. #include <linux/string.h>
  11. #include <linux/printk.h>
  12. #include <linux/errno.h>
  13. #include <linux/slab.h>
  14. #include <linux/kexec.h>
  15. #include <linux/kernel.h>
  16. #include <linux/mm.h>
  17. #include <linux/efi.h>
  18. #include <linux/verification.h>
  19. #include <asm/bootparam.h>
  20. #include <asm/setup.h>
  21. #include <asm/crash.h>
  22. #include <asm/efi.h>
  23. #include <asm/e820/api.h>
  24. #include <asm/kexec-bzimage64.h>
  25. #define MAX_ELFCOREHDR_STR_LEN 30 /* elfcorehdr=0x<64bit-value> */
  26. /*
  27. * Defines lowest physical address for various segments. Not sure where
  28. * exactly these limits came from. Current bzimage64 loader in kexec-tools
  29. * uses these so I am retaining it. It can be changed over time as we gain
  30. * more insight.
  31. */
  32. #define MIN_PURGATORY_ADDR 0x3000
  33. #define MIN_BOOTPARAM_ADDR 0x3000
  34. #define MIN_KERNEL_LOAD_ADDR 0x100000
  35. #define MIN_INITRD_LOAD_ADDR 0x1000000
  36. /*
  37. * This is a place holder for all boot loader specific data structure which
  38. * gets allocated in one call but gets freed much later during cleanup
  39. * time. Right now there is only one field but it can grow as need be.
  40. */
  41. struct bzimage64_data {
  42. /*
  43. * Temporary buffer to hold bootparams buffer. This should be
  44. * freed once the bootparam segment has been loaded.
  45. */
  46. void *bootparams_buf;
  47. };
  48. static int setup_initrd(struct boot_params *params,
  49. unsigned long initrd_load_addr, unsigned long initrd_len)
  50. {
  51. params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
  52. params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
  53. params->ext_ramdisk_image = initrd_load_addr >> 32;
  54. params->ext_ramdisk_size = initrd_len >> 32;
  55. return 0;
  56. }
  57. static int setup_cmdline(struct kimage *image, struct boot_params *params,
  58. unsigned long bootparams_load_addr,
  59. unsigned long cmdline_offset, char *cmdline,
  60. unsigned long cmdline_len)
  61. {
  62. char *cmdline_ptr = ((char *)params) + cmdline_offset;
  63. unsigned long cmdline_ptr_phys, len = 0;
  64. uint32_t cmdline_low_32, cmdline_ext_32;
  65. if (image->type == KEXEC_TYPE_CRASH) {
  66. len = sprintf(cmdline_ptr,
  67. "elfcorehdr=0x%lx ", image->arch.elf_load_addr);
  68. }
  69. memcpy(cmdline_ptr + len, cmdline, cmdline_len);
  70. cmdline_len += len;
  71. cmdline_ptr[cmdline_len - 1] = '\0';
  72. pr_debug("Final command line is: %s\n", cmdline_ptr);
  73. cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
  74. cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
  75. cmdline_ext_32 = cmdline_ptr_phys >> 32;
  76. params->hdr.cmd_line_ptr = cmdline_low_32;
  77. if (cmdline_ext_32)
  78. params->ext_cmd_line_ptr = cmdline_ext_32;
  79. return 0;
  80. }
  81. static int setup_e820_entries(struct boot_params *params)
  82. {
  83. unsigned int nr_e820_entries;
  84. nr_e820_entries = e820_table_kexec->nr_entries;
  85. /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
  86. if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
  87. nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;
  88. params->e820_entries = nr_e820_entries;
  89. memcpy(&params->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));
  90. return 0;
  91. }
  92. #ifdef CONFIG_EFI
  93. static int setup_efi_info_memmap(struct boot_params *params,
  94. unsigned long params_load_addr,
  95. unsigned int efi_map_offset,
  96. unsigned int efi_map_sz)
  97. {
  98. void *efi_map = (void *)params + efi_map_offset;
  99. unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
  100. struct efi_info *ei = &params->efi_info;
  101. if (!efi_map_sz)
  102. return 0;
  103. efi_runtime_map_copy(efi_map, efi_map_sz);
  104. ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
  105. ei->efi_memmap_hi = efi_map_phys_addr >> 32;
  106. ei->efi_memmap_size = efi_map_sz;
  107. return 0;
  108. }
  109. static int
  110. prepare_add_efi_setup_data(struct boot_params *params,
  111. unsigned long params_load_addr,
  112. unsigned int efi_setup_data_offset)
  113. {
  114. unsigned long setup_data_phys;
  115. struct setup_data *sd = (void *)params + efi_setup_data_offset;
  116. struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
  117. esd->fw_vendor = efi_fw_vendor;
  118. esd->tables = efi_config_table;
  119. esd->smbios = efi.smbios;
  120. sd->type = SETUP_EFI;
  121. sd->len = sizeof(struct efi_setup_data);
  122. /* Add setup data */
  123. setup_data_phys = params_load_addr + efi_setup_data_offset;
  124. sd->next = params->hdr.setup_data;
  125. params->hdr.setup_data = setup_data_phys;
  126. return 0;
  127. }
  128. static int
  129. setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
  130. unsigned int efi_map_offset, unsigned int efi_map_sz,
  131. unsigned int efi_setup_data_offset)
  132. {
  133. struct efi_info *current_ei = &boot_params.efi_info;
  134. struct efi_info *ei = &params->efi_info;
  135. if (!efi_enabled(EFI_RUNTIME_SERVICES))
  136. return 0;
  137. if (!current_ei->efi_memmap_size)
  138. return 0;
  139. params->secure_boot = boot_params.secure_boot;
  140. ei->efi_loader_signature = current_ei->efi_loader_signature;
  141. ei->efi_systab = current_ei->efi_systab;
  142. ei->efi_systab_hi = current_ei->efi_systab_hi;
  143. ei->efi_memdesc_version = current_ei->efi_memdesc_version;
  144. ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
  145. setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
  146. efi_map_sz);
  147. prepare_add_efi_setup_data(params, params_load_addr,
  148. efi_setup_data_offset);
  149. return 0;
  150. }
  151. #endif /* CONFIG_EFI */
  152. static int
  153. setup_boot_parameters(struct kimage *image, struct boot_params *params,
  154. unsigned long params_load_addr,
  155. unsigned int efi_map_offset, unsigned int efi_map_sz,
  156. unsigned int efi_setup_data_offset)
  157. {
  158. unsigned int nr_e820_entries;
  159. unsigned long long mem_k, start, end;
  160. int i, ret = 0;
  161. /* Get subarch from existing bootparams */
  162. params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
  163. /* Copying screen_info will do? */
  164. memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
  165. /* Fill in memsize later */
  166. params->screen_info.ext_mem_k = 0;
  167. params->alt_mem_k = 0;
  168. /* Always fill in RSDP: it is either 0 or a valid value */
  169. params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
  170. /* Default APM info */
  171. memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
  172. /* Default drive info */
  173. memset(&params->hd0_info, 0, sizeof(params->hd0_info));
  174. memset(&params->hd1_info, 0, sizeof(params->hd1_info));
  175. if (image->type == KEXEC_TYPE_CRASH) {
  176. ret = crash_setup_memmap_entries(image, params);
  177. if (ret)
  178. return ret;
  179. } else
  180. setup_e820_entries(params);
  181. nr_e820_entries = params->e820_entries;
  182. for (i = 0; i < nr_e820_entries; i++) {
  183. if (params->e820_table[i].type != E820_TYPE_RAM)
  184. continue;
  185. start = params->e820_table[i].addr;
  186. end = params->e820_table[i].addr + params->e820_table[i].size - 1;
  187. if ((start <= 0x100000) && end > 0x100000) {
  188. mem_k = (end >> 10) - (0x100000 >> 10);
  189. params->screen_info.ext_mem_k = mem_k;
  190. params->alt_mem_k = mem_k;
  191. if (mem_k > 0xfc00)
  192. params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
  193. if (mem_k > 0xffffffff)
  194. params->alt_mem_k = 0xffffffff;
  195. }
  196. }
  197. #ifdef CONFIG_EFI
  198. /* Setup EFI state */
  199. setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
  200. efi_setup_data_offset);
  201. #endif
  202. /* Setup EDD info */
  203. memcpy(params->eddbuf, boot_params.eddbuf,
  204. EDDMAXNR * sizeof(struct edd_info));
  205. params->eddbuf_entries = boot_params.eddbuf_entries;
  206. memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
  207. EDD_MBR_SIG_MAX * sizeof(unsigned int));
  208. return ret;
  209. }
  210. static int bzImage64_probe(const char *buf, unsigned long len)
  211. {
  212. int ret = -ENOEXEC;
  213. struct setup_header *header;
  214. /* kernel should be at least two sectors long */
  215. if (len < 2 * 512) {
  216. pr_err("File is too short to be a bzImage\n");
  217. return ret;
  218. }
  219. header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
  220. if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
  221. pr_err("Not a bzImage\n");
  222. return ret;
  223. }
  224. if (header->boot_flag != 0xAA55) {
  225. pr_err("No x86 boot sector present\n");
  226. return ret;
  227. }
  228. if (header->version < 0x020C) {
  229. pr_err("Must be at least protocol version 2.12\n");
  230. return ret;
  231. }
  232. if (!(header->loadflags & LOADED_HIGH)) {
  233. pr_err("zImage not a bzImage\n");
  234. return ret;
  235. }
  236. if (!(header->xloadflags & XLF_KERNEL_64)) {
  237. pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
  238. return ret;
  239. }
  240. if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
  241. pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
  242. return ret;
  243. }
  244. /*
  245. * Can't handle 32bit EFI as it does not allow loading kernel
  246. * above 4G. This should be handled by 32bit bzImage loader
  247. */
  248. if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
  249. pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
  250. return ret;
  251. }
  252. if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
  253. pr_err("bzImage cannot handle 5-level paging mode.\n");
  254. return ret;
  255. }
  256. /* I've got a bzImage */
  257. pr_debug("It's a relocatable bzImage64\n");
  258. ret = 0;
  259. return ret;
  260. }
  261. static void *bzImage64_load(struct kimage *image, char *kernel,
  262. unsigned long kernel_len, char *initrd,
  263. unsigned long initrd_len, char *cmdline,
  264. unsigned long cmdline_len)
  265. {
  266. struct setup_header *header;
  267. int setup_sects, kern16_size, ret = 0;
  268. unsigned long setup_header_size, params_cmdline_sz;
  269. struct boot_params *params;
  270. unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
  271. struct bzimage64_data *ldata;
  272. struct kexec_entry64_regs regs64;
  273. void *stack;
  274. unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
  275. unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
  276. struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
  277. .top_down = true };
  278. struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
  279. .buf_max = ULONG_MAX, .top_down = true };
  280. header = (struct setup_header *)(kernel + setup_hdr_offset);
  281. setup_sects = header->setup_sects;
  282. if (setup_sects == 0)
  283. setup_sects = 4;
  284. kern16_size = (setup_sects + 1) * 512;
  285. if (kernel_len < kern16_size) {
  286. pr_err("bzImage truncated\n");
  287. return ERR_PTR(-ENOEXEC);
  288. }
  289. if (cmdline_len > header->cmdline_size) {
  290. pr_err("Kernel command line too long\n");
  291. return ERR_PTR(-EINVAL);
  292. }
  293. /*
  294. * In case of crash dump, we will append elfcorehdr=<addr> to
  295. * command line. Make sure it does not overflow
  296. */
  297. if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
  298. pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
  299. return ERR_PTR(-EINVAL);
  300. }
  301. /* Allocate and load backup region */
  302. if (image->type == KEXEC_TYPE_CRASH) {
  303. ret = crash_load_segments(image);
  304. if (ret)
  305. return ERR_PTR(ret);
  306. }
  307. /*
  308. * Load purgatory. For 64bit entry point, purgatory code can be
  309. * anywhere.
  310. */
  311. ret = kexec_load_purgatory(image, &pbuf);
  312. if (ret) {
  313. pr_err("Loading purgatory failed\n");
  314. return ERR_PTR(ret);
  315. }
  316. pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
  317. /*
  318. * Load Bootparams and cmdline and space for efi stuff.
  319. *
  320. * Allocate memory together for multiple data structures so
  321. * that they all can go in single area/segment and we don't
  322. * have to create separate segment for each. Keeps things
  323. * little bit simple
  324. */
  325. efi_map_sz = efi_get_runtime_map_size();
  326. params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
  327. MAX_ELFCOREHDR_STR_LEN;
  328. params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
  329. kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
  330. sizeof(struct setup_data) +
  331. sizeof(struct efi_setup_data);
  332. params = kzalloc(kbuf.bufsz, GFP_KERNEL);
  333. if (!params)
  334. return ERR_PTR(-ENOMEM);
  335. efi_map_offset = params_cmdline_sz;
  336. efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
  337. /* Copy setup header onto bootparams. Documentation/x86/boot.rst */
  338. setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
  339. /* Is there a limit on setup header size? */
  340. memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
  341. kbuf.buffer = params;
  342. kbuf.memsz = kbuf.bufsz;
  343. kbuf.buf_align = 16;
  344. kbuf.buf_min = MIN_BOOTPARAM_ADDR;
  345. ret = kexec_add_buffer(&kbuf);
  346. if (ret)
  347. goto out_free_params;
  348. bootparam_load_addr = kbuf.mem;
  349. pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
  350. bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
  351. /* Load kernel */
  352. kbuf.buffer = kernel + kern16_size;
  353. kbuf.bufsz = kernel_len - kern16_size;
  354. kbuf.memsz = PAGE_ALIGN(header->init_size);
  355. kbuf.buf_align = header->kernel_alignment;
  356. kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
  357. kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
  358. ret = kexec_add_buffer(&kbuf);
  359. if (ret)
  360. goto out_free_params;
  361. kernel_load_addr = kbuf.mem;
  362. pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
  363. kernel_load_addr, kbuf.bufsz, kbuf.memsz);
  364. /* Load initrd high */
  365. if (initrd) {
  366. kbuf.buffer = initrd;
  367. kbuf.bufsz = kbuf.memsz = initrd_len;
  368. kbuf.buf_align = PAGE_SIZE;
  369. kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
  370. kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
  371. ret = kexec_add_buffer(&kbuf);
  372. if (ret)
  373. goto out_free_params;
  374. initrd_load_addr = kbuf.mem;
  375. pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
  376. initrd_load_addr, initrd_len, initrd_len);
  377. setup_initrd(params, initrd_load_addr, initrd_len);
  378. }
  379. setup_cmdline(image, params, bootparam_load_addr,
  380. sizeof(struct boot_params), cmdline, cmdline_len);
  381. /* bootloader info. Do we need a separate ID for kexec kernel loader? */
  382. params->hdr.type_of_loader = 0x0D << 4;
  383. params->hdr.loadflags = 0;
  384. /* Setup purgatory regs for entry */
  385. ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
  386. sizeof(regs64), 1);
  387. if (ret)
  388. goto out_free_params;
  389. regs64.rbx = 0; /* Bootstrap Processor */
  390. regs64.rsi = bootparam_load_addr;
  391. regs64.rip = kernel_load_addr + 0x200;
  392. stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
  393. if (IS_ERR(stack)) {
  394. pr_err("Could not find address of symbol stack_end\n");
  395. ret = -EINVAL;
  396. goto out_free_params;
  397. }
  398. regs64.rsp = (unsigned long)stack;
  399. ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
  400. sizeof(regs64), 0);
  401. if (ret)
  402. goto out_free_params;
  403. ret = setup_boot_parameters(image, params, bootparam_load_addr,
  404. efi_map_offset, efi_map_sz,
  405. efi_setup_data_offset);
  406. if (ret)
  407. goto out_free_params;
  408. /* Allocate loader specific data */
  409. ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
  410. if (!ldata) {
  411. ret = -ENOMEM;
  412. goto out_free_params;
  413. }
  414. /*
  415. * Store pointer to params so that it could be freed after loading
  416. * params segment has been loaded and contents have been copied
  417. * somewhere else.
  418. */
  419. ldata->bootparams_buf = params;
  420. return ldata;
  421. out_free_params:
  422. kfree(params);
  423. return ERR_PTR(ret);
  424. }
  425. /* This cleanup function is called after various segments have been loaded */
  426. static int bzImage64_cleanup(void *loader_data)
  427. {
  428. struct bzimage64_data *ldata = loader_data;
  429. if (!ldata)
  430. return 0;
  431. kfree(ldata->bootparams_buf);
  432. ldata->bootparams_buf = NULL;
  433. return 0;
  434. }
  435. #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
  436. static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
  437. {
  438. int ret;
  439. ret = verify_pefile_signature(kernel, kernel_len,
  440. VERIFY_USE_SECONDARY_KEYRING,
  441. VERIFYING_KEXEC_PE_SIGNATURE);
  442. if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
  443. ret = verify_pefile_signature(kernel, kernel_len,
  444. VERIFY_USE_PLATFORM_KEYRING,
  445. VERIFYING_KEXEC_PE_SIGNATURE);
  446. }
  447. return ret;
  448. }
  449. #endif
  450. const struct kexec_file_ops kexec_bzImage64_ops = {
  451. .probe = bzImage64_probe,
  452. .load = bzImage64_load,
  453. .cleanup = bzImage64_cleanup,
  454. #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
  455. .verify_sig = bzImage64_verify_sig,
  456. #endif
  457. };