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
10#define pr_fmt(fmt) "kexec-bzImage64: " fmt
11
12#include <linux/string.h>
13#include <linux/printk.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/kexec.h>
17#include <linux/kernel.h>
18#include <linux/mm.h>
19#include <linux/efi.h>
20#include <linux/random.h>
21
22#include <asm/bootparam.h>
23#include <asm/setup.h>
24#include <asm/crash.h>
25#include <asm/efi.h>
26#include <asm/e820/api.h>
27#include <asm/kexec-bzimage64.h>
28
29#define MAX_ELFCOREHDR_STR_LEN 30 /* elfcorehdr=0x<64bit-value> */
30
31/*
32 * Defines lowest physical address for various segments. Not sure where
33 * exactly these limits came from. Current bzimage64 loader in kexec-tools
34 * uses these so I am retaining it. It can be changed over time as we gain
35 * more insight.
36 */
37#define MIN_PURGATORY_ADDR 0x3000
38#define MIN_BOOTPARAM_ADDR 0x3000
39#define MIN_KERNEL_LOAD_ADDR 0x100000
40#define MIN_INITRD_LOAD_ADDR 0x1000000
41
42/*
43 * This is a place holder for all boot loader specific data structure which
44 * gets allocated in one call but gets freed much later during cleanup
45 * time. Right now there is only one field but it can grow as need be.
46 */
47struct bzimage64_data {
48 /*
49 * Temporary buffer to hold bootparams buffer. This should be
50 * freed once the bootparam segment has been loaded.
51 */
52 void *bootparams_buf;
53};
54
55static int setup_initrd(struct boot_params *params,
56 unsigned long initrd_load_addr, unsigned long initrd_len)
57{
58 params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
59 params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;
60
61 params->ext_ramdisk_image = initrd_load_addr >> 32;
62 params->ext_ramdisk_size = initrd_len >> 32;
63
64 return 0;
65}
66
67static int setup_cmdline(struct kimage *image, struct boot_params *params,
68 unsigned long bootparams_load_addr,
69 unsigned long cmdline_offset, char *cmdline,
70 unsigned long cmdline_len)
71{
72 char *cmdline_ptr = ((char *)params) + cmdline_offset;
73 unsigned long cmdline_ptr_phys, len = 0;
74 uint32_t cmdline_low_32, cmdline_ext_32;
75
76 if (image->type == KEXEC_TYPE_CRASH) {
77 len = sprintf(buf: cmdline_ptr,
78 fmt: "elfcorehdr=0x%lx ", image->elf_load_addr);
79 }
80 memcpy(cmdline_ptr + len, cmdline, cmdline_len);
81 cmdline_len += len;
82
83 cmdline_ptr[cmdline_len - 1] = '\0';
84
85 pr_debug("Final command line is: %s\n", cmdline_ptr);
86 cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
87 cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
88 cmdline_ext_32 = cmdline_ptr_phys >> 32;
89
90 params->hdr.cmd_line_ptr = cmdline_low_32;
91 if (cmdline_ext_32)
92 params->ext_cmd_line_ptr = cmdline_ext_32;
93
94 return 0;
95}
96
97static int setup_e820_entries(struct boot_params *params)
98{
99 unsigned int nr_e820_entries;
100
101 nr_e820_entries = e820_table_kexec->nr_entries;
102
103 /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
104 if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
105 nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;
106
107 params->e820_entries = nr_e820_entries;
108 memcpy(&params->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));
109
110 return 0;
111}
112
113enum { RNG_SEED_LENGTH = 32 };
114
115static void
116setup_rng_seed(struct boot_params *params, unsigned long params_load_addr,
117 unsigned int rng_seed_setup_data_offset)
118{
119 struct setup_data *sd = (void *)params + rng_seed_setup_data_offset;
120 unsigned long setup_data_phys;
121
122 if (!rng_is_initialized())
123 return;
124
125 sd->type = SETUP_RNG_SEED;
126 sd->len = RNG_SEED_LENGTH;
127 get_random_bytes(buf: sd->data, len: RNG_SEED_LENGTH);
128 setup_data_phys = params_load_addr + rng_seed_setup_data_offset;
129 sd->next = params->hdr.setup_data;
130 params->hdr.setup_data = setup_data_phys;
131}
132
133#ifdef CONFIG_EFI
134static int setup_efi_info_memmap(struct boot_params *params,
135 unsigned long params_load_addr,
136 unsigned int efi_map_offset,
137 unsigned int efi_map_sz)
138{
139 void *efi_map = (void *)params + efi_map_offset;
140 unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
141 struct efi_info *ei = &params->efi_info;
142
143 if (!efi_map_sz)
144 return 0;
145
146 efi_runtime_map_copy(buf: efi_map, bufsz: efi_map_sz);
147
148 ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
149 ei->efi_memmap_hi = efi_map_phys_addr >> 32;
150 ei->efi_memmap_size = efi_map_sz;
151
152 return 0;
153}
154
155static int
156prepare_add_efi_setup_data(struct boot_params *params,
157 unsigned long params_load_addr,
158 unsigned int efi_setup_data_offset)
159{
160 unsigned long setup_data_phys;
161 struct setup_data *sd = (void *)params + efi_setup_data_offset;
162 struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
163
164 esd->fw_vendor = efi_fw_vendor;
165 esd->tables = efi_config_table;
166 esd->smbios = efi.smbios;
167
168 sd->type = SETUP_EFI;
169 sd->len = sizeof(struct efi_setup_data);
170
171 /* Add setup data */
172 setup_data_phys = params_load_addr + efi_setup_data_offset;
173 sd->next = params->hdr.setup_data;
174 params->hdr.setup_data = setup_data_phys;
175
176 return 0;
177}
178
179static int
180setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
181 unsigned int efi_map_offset, unsigned int efi_map_sz,
182 unsigned int efi_setup_data_offset)
183{
184 struct efi_info *current_ei = &boot_params.efi_info;
185 struct efi_info *ei = &params->efi_info;
186
187 if (!efi_enabled(EFI_RUNTIME_SERVICES))
188 return 0;
189
190 if (!current_ei->efi_memmap_size)
191 return 0;
192
193 params->secure_boot = boot_params.secure_boot;
194 ei->efi_loader_signature = current_ei->efi_loader_signature;
195 ei->efi_systab = current_ei->efi_systab;
196 ei->efi_systab_hi = current_ei->efi_systab_hi;
197
198 ei->efi_memdesc_version = current_ei->efi_memdesc_version;
199 ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
200
201 setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
202 efi_map_sz);
203 prepare_add_efi_setup_data(params, params_load_addr,
204 efi_setup_data_offset);
205 return 0;
206}
207#endif /* CONFIG_EFI */
208
209static void
210setup_ima_state(const struct kimage *image, struct boot_params *params,
211 unsigned long params_load_addr,
212 unsigned int ima_setup_data_offset)
213{
214#ifdef CONFIG_IMA_KEXEC
215 struct setup_data *sd = (void *)params + ima_setup_data_offset;
216 unsigned long setup_data_phys;
217 struct ima_setup_data *ima;
218
219 if (!image->ima_buffer_size)
220 return;
221
222 sd->type = SETUP_IMA;
223 sd->len = sizeof(*ima);
224
225 ima = (void *)sd + sizeof(struct setup_data);
226 ima->addr = image->ima_buffer_addr;
227 ima->size = image->ima_buffer_size;
228
229 /* Add setup data */
230 setup_data_phys = params_load_addr + ima_setup_data_offset;
231 sd->next = params->hdr.setup_data;
232 params->hdr.setup_data = setup_data_phys;
233#endif /* CONFIG_IMA_KEXEC */
234}
235
236static int
237setup_boot_parameters(struct kimage *image, struct boot_params *params,
238 unsigned long params_load_addr,
239 unsigned int efi_map_offset, unsigned int efi_map_sz,
240 unsigned int setup_data_offset)
241{
242 unsigned int nr_e820_entries;
243 unsigned long long mem_k, start, end;
244 int i, ret = 0;
245
246 /* Get subarch from existing bootparams */
247 params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
248
249 /* Copying screen_info will do? */
250 memcpy(&params->screen_info, &screen_info, sizeof(struct screen_info));
251
252 /* Fill in memsize later */
253 params->screen_info.ext_mem_k = 0;
254 params->alt_mem_k = 0;
255
256 /* Always fill in RSDP: it is either 0 or a valid value */
257 params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;
258
259 /* Default APM info */
260 memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));
261
262 /* Default drive info */
263 memset(&params->hd0_info, 0, sizeof(params->hd0_info));
264 memset(&params->hd1_info, 0, sizeof(params->hd1_info));
265
266 if (image->type == KEXEC_TYPE_CRASH) {
267 ret = crash_setup_memmap_entries(image, params);
268 if (ret)
269 return ret;
270 } else
271 setup_e820_entries(params);
272
273 nr_e820_entries = params->e820_entries;
274
275 for (i = 0; i < nr_e820_entries; i++) {
276 if (params->e820_table[i].type != E820_TYPE_RAM)
277 continue;
278 start = params->e820_table[i].addr;
279 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
280
281 if ((start <= 0x100000) && end > 0x100000) {
282 mem_k = (end >> 10) - (0x100000 >> 10);
283 params->screen_info.ext_mem_k = mem_k;
284 params->alt_mem_k = mem_k;
285 if (mem_k > 0xfc00)
286 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
287 if (mem_k > 0xffffffff)
288 params->alt_mem_k = 0xffffffff;
289 }
290 }
291
292#ifdef CONFIG_EFI
293 /* Setup EFI state */
294 setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
295 efi_setup_data_offset: setup_data_offset);
296 setup_data_offset += sizeof(struct setup_data) +
297 sizeof(struct efi_setup_data);
298#endif
299
300 if (IS_ENABLED(CONFIG_IMA_KEXEC)) {
301 /* Setup IMA log buffer state */
302 setup_ima_state(image, params, params_load_addr,
303 ima_setup_data_offset: setup_data_offset);
304 setup_data_offset += sizeof(struct setup_data) +
305 sizeof(struct ima_setup_data);
306 }
307
308 /* Setup RNG seed */
309 setup_rng_seed(params, params_load_addr, rng_seed_setup_data_offset: setup_data_offset);
310
311 /* Setup EDD info */
312 memcpy(params->eddbuf, boot_params.eddbuf,
313 EDDMAXNR * sizeof(struct edd_info));
314 params->eddbuf_entries = boot_params.eddbuf_entries;
315
316 memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
317 EDD_MBR_SIG_MAX * sizeof(unsigned int));
318
319 return ret;
320}
321
322static int bzImage64_probe(const char *buf, unsigned long len)
323{
324 int ret = -ENOEXEC;
325 struct setup_header *header;
326
327 /* kernel should be at least two sectors long */
328 if (len < 2 * 512) {
329 pr_err("File is too short to be a bzImage\n");
330 return ret;
331 }
332
333 header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
334 if (memcmp(p: (char *)&header->header, q: "HdrS", size: 4) != 0) {
335 pr_err("Not a bzImage\n");
336 return ret;
337 }
338
339 if (header->boot_flag != 0xAA55) {
340 pr_err("No x86 boot sector present\n");
341 return ret;
342 }
343
344 if (header->version < 0x020C) {
345 pr_err("Must be at least protocol version 2.12\n");
346 return ret;
347 }
348
349 if (!(header->loadflags & LOADED_HIGH)) {
350 pr_err("zImage not a bzImage\n");
351 return ret;
352 }
353
354 if (!(header->xloadflags & XLF_KERNEL_64)) {
355 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
356 return ret;
357 }
358
359 if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
360 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
361 return ret;
362 }
363
364 /*
365 * Can't handle 32bit EFI as it does not allow loading kernel
366 * above 4G. This should be handled by 32bit bzImage loader
367 */
368 if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
369 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
370 return ret;
371 }
372
373 if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
374 pr_err("bzImage cannot handle 5-level paging mode.\n");
375 return ret;
376 }
377
378 /* I've got a bzImage */
379 pr_debug("It's a relocatable bzImage64\n");
380 ret = 0;
381
382 return ret;
383}
384
385static void *bzImage64_load(struct kimage *image, char *kernel,
386 unsigned long kernel_len, char *initrd,
387 unsigned long initrd_len, char *cmdline,
388 unsigned long cmdline_len)
389{
390
391 struct setup_header *header;
392 int setup_sects, kern16_size, ret = 0;
393 unsigned long setup_header_size, params_cmdline_sz;
394 struct boot_params *params;
395 unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
396 struct bzimage64_data *ldata;
397 struct kexec_entry64_regs regs64;
398 void *stack;
399 unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
400 unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
401 struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
402 .top_down = true };
403 struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
404 .buf_max = ULONG_MAX, .top_down = true };
405
406 header = (struct setup_header *)(kernel + setup_hdr_offset);
407 setup_sects = header->setup_sects;
408 if (setup_sects == 0)
409 setup_sects = 4;
410
411 kern16_size = (setup_sects + 1) * 512;
412 if (kernel_len < kern16_size) {
413 pr_err("bzImage truncated\n");
414 return ERR_PTR(error: -ENOEXEC);
415 }
416
417 if (cmdline_len > header->cmdline_size) {
418 pr_err("Kernel command line too long\n");
419 return ERR_PTR(error: -EINVAL);
420 }
421
422 /*
423 * In case of crash dump, we will append elfcorehdr=<addr> to
424 * command line. Make sure it does not overflow
425 */
426 if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
427 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
428 return ERR_PTR(error: -EINVAL);
429 }
430
431 /* Allocate and load backup region */
432 if (image->type == KEXEC_TYPE_CRASH) {
433 ret = crash_load_segments(image);
434 if (ret)
435 return ERR_PTR(error: ret);
436 }
437
438 /*
439 * Load purgatory. For 64bit entry point, purgatory code can be
440 * anywhere.
441 */
442 ret = kexec_load_purgatory(image, kbuf: &pbuf);
443 if (ret) {
444 pr_err("Loading purgatory failed\n");
445 return ERR_PTR(error: ret);
446 }
447
448 pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
449
450
451 /*
452 * Load Bootparams and cmdline and space for efi stuff.
453 *
454 * Allocate memory together for multiple data structures so
455 * that they all can go in single area/segment and we don't
456 * have to create separate segment for each. Keeps things
457 * little bit simple
458 */
459 efi_map_sz = efi_get_runtime_map_size();
460 params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
461 MAX_ELFCOREHDR_STR_LEN;
462 params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
463 kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
464 sizeof(struct setup_data) +
465 sizeof(struct efi_setup_data) +
466 sizeof(struct setup_data) +
467 RNG_SEED_LENGTH;
468
469 if (IS_ENABLED(CONFIG_IMA_KEXEC))
470 kbuf.bufsz += sizeof(struct setup_data) +
471 sizeof(struct ima_setup_data);
472
473 params = kzalloc(size: kbuf.bufsz, GFP_KERNEL);
474 if (!params)
475 return ERR_PTR(error: -ENOMEM);
476 efi_map_offset = params_cmdline_sz;
477 efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
478
479 /* Copy setup header onto bootparams. Documentation/arch/x86/boot.rst */
480 setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
481
482 /* Is there a limit on setup header size? */
483 memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
484
485 kbuf.buffer = params;
486 kbuf.memsz = kbuf.bufsz;
487 kbuf.buf_align = 16;
488 kbuf.buf_min = MIN_BOOTPARAM_ADDR;
489 ret = kexec_add_buffer(kbuf: &kbuf);
490 if (ret)
491 goto out_free_params;
492 bootparam_load_addr = kbuf.mem;
493 pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
494 bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
495
496 /* Load kernel */
497 kbuf.buffer = kernel + kern16_size;
498 kbuf.bufsz = kernel_len - kern16_size;
499 kbuf.memsz = PAGE_ALIGN(header->init_size);
500 kbuf.buf_align = header->kernel_alignment;
501 kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
502 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
503 ret = kexec_add_buffer(kbuf: &kbuf);
504 if (ret)
505 goto out_free_params;
506 kernel_load_addr = kbuf.mem;
507
508 pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
509 kernel_load_addr, kbuf.bufsz, kbuf.memsz);
510
511 /* Load initrd high */
512 if (initrd) {
513 kbuf.buffer = initrd;
514 kbuf.bufsz = kbuf.memsz = initrd_len;
515 kbuf.buf_align = PAGE_SIZE;
516 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
517 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
518 ret = kexec_add_buffer(kbuf: &kbuf);
519 if (ret)
520 goto out_free_params;
521 initrd_load_addr = kbuf.mem;
522
523 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
524 initrd_load_addr, initrd_len, initrd_len);
525
526 setup_initrd(params, initrd_load_addr, initrd_len);
527 }
528
529 setup_cmdline(image, params, bootparams_load_addr: bootparam_load_addr,
530 cmdline_offset: sizeof(struct boot_params), cmdline, cmdline_len);
531
532 /* bootloader info. Do we need a separate ID for kexec kernel loader? */
533 params->hdr.type_of_loader = 0x0D << 4;
534 params->hdr.loadflags = 0;
535
536 /* Setup purgatory regs for entry */
537 ret = kexec_purgatory_get_set_symbol(image, name: "entry64_regs", buf: &regs64,
538 size: sizeof(regs64), get_value: 1);
539 if (ret)
540 goto out_free_params;
541
542 regs64.rbx = 0; /* Bootstrap Processor */
543 regs64.rsi = bootparam_load_addr;
544 regs64.rip = kernel_load_addr + 0x200;
545 stack = kexec_purgatory_get_symbol_addr(image, name: "stack_end");
546 if (IS_ERR(ptr: stack)) {
547 pr_err("Could not find address of symbol stack_end\n");
548 ret = -EINVAL;
549 goto out_free_params;
550 }
551
552 regs64.rsp = (unsigned long)stack;
553 ret = kexec_purgatory_get_set_symbol(image, name: "entry64_regs", buf: &regs64,
554 size: sizeof(regs64), get_value: 0);
555 if (ret)
556 goto out_free_params;
557
558 ret = setup_boot_parameters(image, params, params_load_addr: bootparam_load_addr,
559 efi_map_offset, efi_map_sz,
560 setup_data_offset: efi_setup_data_offset);
561 if (ret)
562 goto out_free_params;
563
564 /* Allocate loader specific data */
565 ldata = kzalloc(size: sizeof(struct bzimage64_data), GFP_KERNEL);
566 if (!ldata) {
567 ret = -ENOMEM;
568 goto out_free_params;
569 }
570
571 /*
572 * Store pointer to params so that it could be freed after loading
573 * params segment has been loaded and contents have been copied
574 * somewhere else.
575 */
576 ldata->bootparams_buf = params;
577 return ldata;
578
579out_free_params:
580 kfree(objp: params);
581 return ERR_PTR(error: ret);
582}
583
584/* This cleanup function is called after various segments have been loaded */
585static int bzImage64_cleanup(void *loader_data)
586{
587 struct bzimage64_data *ldata = loader_data;
588
589 if (!ldata)
590 return 0;
591
592 kfree(objp: ldata->bootparams_buf);
593 ldata->bootparams_buf = NULL;
594
595 return 0;
596}
597
598const struct kexec_file_ops kexec_bzImage64_ops = {
599 .probe = bzImage64_probe,
600 .load = bzImage64_load,
601 .cleanup = bzImage64_cleanup,
602#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
603 .verify_sig = kexec_kernel_verify_pe_sig,
604#endif
605};
606

source code of linux/arch/x86/kernel/kexec-bzimage64.c