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
setup_initrd(struct boot_params * params,unsigned long initrd_load_addr,unsigned long initrd_len)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
setup_cmdline(struct kimage * image,struct boot_params * params,unsigned long bootparams_load_addr,unsigned long cmdline_offset,char * cmdline,unsigned long cmdline_len)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
setup_e820_entries(struct boot_params * params)99 static int setup_e820_entries(struct boot_params *params)
100 {
101 unsigned int nr_e820_entries;
102
103 nr_e820_entries = e820_table_kexec->nr_entries;
104
105 /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
106 if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
107 nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;
108
109 params->e820_entries = nr_e820_entries;
110 memcpy(¶ms->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));
111
112 return 0;
113 }
114
115 #ifdef CONFIG_EFI
setup_efi_info_memmap(struct boot_params * params,unsigned long params_load_addr,unsigned int efi_map_offset,unsigned int efi_map_sz)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 = ¶ms->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
prepare_add_efi_setup_data(struct boot_params * params,unsigned long params_load_addr,unsigned int efi_setup_data_offset)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
setup_efi_state(struct boot_params * params,unsigned long params_load_addr,unsigned int efi_map_offset,unsigned int efi_map_sz,unsigned int efi_setup_data_offset)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 = ¶ms->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
setup_boot_parameters(struct kimage * image,struct boot_params * params,unsigned long params_load_addr,unsigned int efi_map_offset,unsigned int efi_map_sz,unsigned int efi_setup_data_offset)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(¶ms->screen_info, &boot_params.screen_info,
215 sizeof(struct screen_info));
216
217 /* Fill in memsize later */
218 params->screen_info.ext_mem_k = 0;
219 params->alt_mem_k = 0;
220
221 /* Default APM info */
222 memset(¶ms->apm_bios_info, 0, sizeof(params->apm_bios_info));
223
224 /* Default drive info */
225 memset(¶ms->hd0_info, 0, sizeof(params->hd0_info));
226 memset(¶ms->hd1_info, 0, sizeof(params->hd1_info));
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_table[i].type != E820_TYPE_RAM)
239 continue;
240 start = params->e820_table[i].addr;
241 end = params->e820_table[i].addr + params->e820_table[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
bzImage64_probe(const char * buf,unsigned long len)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 at least 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
bzImage64_load(struct kimage * image,char * kernel,unsigned long kernel_len,char * initrd,unsigned long initrd_len,char * cmdline,unsigned long cmdline_len)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;
338 struct boot_params *params;
339 unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
340 unsigned long purgatory_load_addr;
341 struct bzimage64_data *ldata;
342 struct kexec_entry64_regs regs64;
343 void *stack;
344 unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
345 unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
346 struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
347 .top_down = true };
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 params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
405 MAX_ELFCOREHDR_STR_LEN;
406 params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
407 kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
408 sizeof(struct setup_data) +
409 sizeof(struct efi_setup_data);
410
411 params = kzalloc(kbuf.bufsz, 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 + ALIGN(efi_map_sz, 16);
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(¶ms->hdr, (kernel + setup_hdr_offset), setup_header_size);
422
423 kbuf.buffer = params;
424 kbuf.memsz = kbuf.bufsz;
425 kbuf.buf_align = 16;
426 kbuf.buf_min = MIN_BOOTPARAM_ADDR;
427 ret = kexec_add_buffer(&kbuf);
428 if (ret)
429 goto out_free_params;
430 bootparam_load_addr = kbuf.mem;
431 pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
432 bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
433
434 /* Load kernel */
435 kbuf.buffer = kernel + kern16_size;
436 kbuf.bufsz = kernel_len - kern16_size;
437 kbuf.memsz = PAGE_ALIGN(header->init_size);
438 kbuf.buf_align = header->kernel_alignment;
439 kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
440 ret = kexec_add_buffer(&kbuf);
441 if (ret)
442 goto out_free_params;
443 kernel_load_addr = kbuf.mem;
444
445 pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
446 kernel_load_addr, kbuf.bufsz, kbuf.memsz);
447
448 /* Load initrd high */
449 if (initrd) {
450 kbuf.buffer = initrd;
451 kbuf.bufsz = kbuf.memsz = initrd_len;
452 kbuf.buf_align = PAGE_SIZE;
453 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
454 ret = kexec_add_buffer(&kbuf);
455 if (ret)
456 goto out_free_params;
457 initrd_load_addr = kbuf.mem;
458
459 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
460 initrd_load_addr, initrd_len, initrd_len);
461
462 setup_initrd(params, initrd_load_addr, initrd_len);
463 }
464
465 setup_cmdline(image, params, bootparam_load_addr,
466 sizeof(struct boot_params), cmdline, cmdline_len);
467
468 /* bootloader info. Do we need a separate ID for kexec kernel loader? */
469 params->hdr.type_of_loader = 0x0D << 4;
470 params->hdr.loadflags = 0;
471
472 /* Setup purgatory regs for entry */
473 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
474 sizeof(regs64), 1);
475 if (ret)
476 goto out_free_params;
477
478 regs64.rbx = 0; /* Bootstrap Processor */
479 regs64.rsi = bootparam_load_addr;
480 regs64.rip = kernel_load_addr + 0x200;
481 stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
482 if (IS_ERR(stack)) {
483 pr_err("Could not find address of symbol stack_end\n");
484 ret = -EINVAL;
485 goto out_free_params;
486 }
487
488 regs64.rsp = (unsigned long)stack;
489 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
490 sizeof(regs64), 0);
491 if (ret)
492 goto out_free_params;
493
494 ret = setup_boot_parameters(image, params, bootparam_load_addr,
495 efi_map_offset, efi_map_sz,
496 efi_setup_data_offset);
497 if (ret)
498 goto out_free_params;
499
500 /* Allocate loader specific data */
501 ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
502 if (!ldata) {
503 ret = -ENOMEM;
504 goto out_free_params;
505 }
506
507 /*
508 * Store pointer to params so that it could be freed after loading
509 * params segment has been loaded and contents have been copied
510 * somewhere else.
511 */
512 ldata->bootparams_buf = params;
513 return ldata;
514
515 out_free_params:
516 kfree(params);
517 return ERR_PTR(ret);
518 }
519
520 /* This cleanup function is called after various segments have been loaded */
bzImage64_cleanup(void * loader_data)521 static int bzImage64_cleanup(void *loader_data)
522 {
523 struct bzimage64_data *ldata = loader_data;
524
525 if (!ldata)
526 return 0;
527
528 kfree(ldata->bootparams_buf);
529 ldata->bootparams_buf = NULL;
530
531 return 0;
532 }
533
534 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
bzImage64_verify_sig(const char * kernel,unsigned long kernel_len)535 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
536 {
537 return verify_pefile_signature(kernel, kernel_len,
538 VERIFY_USE_SECONDARY_KEYRING,
539 VERIFYING_KEXEC_PE_SIGNATURE);
540 }
541 #endif
542
543 struct kexec_file_ops kexec_bzImage64_ops = {
544 .probe = bzImage64_probe,
545 .load = bzImage64_load,
546 .cleanup = bzImage64_cleanup,
547 #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
548 .verify_sig = bzImage64_verify_sig,
549 #endif
550 };
551