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 kexec_dprintk("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#ifdef CONFIG_CRASH_DUMP
267 if (image->type == KEXEC_TYPE_CRASH) {
268 ret = crash_setup_memmap_entries(image, params);
269 if (ret)
270 return ret;
271 } else
272#endif
273 setup_e820_entries(params);
274
275 nr_e820_entries = params->e820_entries;
276
277 kexec_dprintk("E820 memmap:\n");
278 for (i = 0; i < nr_e820_entries; i++) {
279 kexec_dprintk("%016llx-%016llx (%d)\n",
280 params->e820_table[i].addr,
281 params->e820_table[i].addr + params->e820_table[i].size - 1,
282 params->e820_table[i].type);
283 if (params->e820_table[i].type != E820_TYPE_RAM)
284 continue;
285 start = params->e820_table[i].addr;
286 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
287
288 if ((start <= 0x100000) && end > 0x100000) {
289 mem_k = (end >> 10) - (0x100000 >> 10);
290 params->screen_info.ext_mem_k = mem_k;
291 params->alt_mem_k = mem_k;
292 if (mem_k > 0xfc00)
293 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
294 if (mem_k > 0xffffffff)
295 params->alt_mem_k = 0xffffffff;
296 }
297 }
298
299#ifdef CONFIG_EFI
300 /* Setup EFI state */
301 setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
302 efi_setup_data_offset: setup_data_offset);
303 setup_data_offset += sizeof(struct setup_data) +
304 sizeof(struct efi_setup_data);
305#endif
306
307 if (IS_ENABLED(CONFIG_IMA_KEXEC)) {
308 /* Setup IMA log buffer state */
309 setup_ima_state(image, params, params_load_addr,
310 ima_setup_data_offset: setup_data_offset);
311 setup_data_offset += sizeof(struct setup_data) +
312 sizeof(struct ima_setup_data);
313 }
314
315 /* Setup RNG seed */
316 setup_rng_seed(params, params_load_addr, rng_seed_setup_data_offset: setup_data_offset);
317
318 /* Setup EDD info */
319 memcpy(params->eddbuf, boot_params.eddbuf,
320 EDDMAXNR * sizeof(struct edd_info));
321 params->eddbuf_entries = boot_params.eddbuf_entries;
322
323 memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
324 EDD_MBR_SIG_MAX * sizeof(unsigned int));
325
326 return ret;
327}
328
329static int bzImage64_probe(const char *buf, unsigned long len)
330{
331 int ret = -ENOEXEC;
332 struct setup_header *header;
333
334 /* kernel should be at least two sectors long */
335 if (len < 2 * 512) {
336 pr_err("File is too short to be a bzImage\n");
337 return ret;
338 }
339
340 header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
341 if (memcmp(p: (char *)&header->header, q: "HdrS", size: 4) != 0) {
342 pr_err("Not a bzImage\n");
343 return ret;
344 }
345
346 if (header->boot_flag != 0xAA55) {
347 pr_err("No x86 boot sector present\n");
348 return ret;
349 }
350
351 if (header->version < 0x020C) {
352 pr_err("Must be at least protocol version 2.12\n");
353 return ret;
354 }
355
356 if (!(header->loadflags & LOADED_HIGH)) {
357 pr_err("zImage not a bzImage\n");
358 return ret;
359 }
360
361 if (!(header->xloadflags & XLF_KERNEL_64)) {
362 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
363 return ret;
364 }
365
366 if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
367 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
368 return ret;
369 }
370
371 /*
372 * Can't handle 32bit EFI as it does not allow loading kernel
373 * above 4G. This should be handled by 32bit bzImage loader
374 */
375 if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
376 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
377 return ret;
378 }
379
380 if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
381 pr_err("bzImage cannot handle 5-level paging mode.\n");
382 return ret;
383 }
384
385 /* I've got a bzImage */
386 pr_debug("It's a relocatable bzImage64\n");
387 ret = 0;
388
389 return ret;
390}
391
392static void *bzImage64_load(struct kimage *image, char *kernel,
393 unsigned long kernel_len, char *initrd,
394 unsigned long initrd_len, char *cmdline,
395 unsigned long cmdline_len)
396{
397
398 struct setup_header *header;
399 int setup_sects, kern16_size, ret = 0;
400 unsigned long setup_header_size, params_cmdline_sz;
401 struct boot_params *params;
402 unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
403 struct bzimage64_data *ldata;
404 struct kexec_entry64_regs regs64;
405 void *stack;
406 unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
407 unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
408 struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
409 .top_down = true };
410 struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
411 .buf_max = ULONG_MAX, .top_down = true };
412
413 header = (struct setup_header *)(kernel + setup_hdr_offset);
414 setup_sects = header->setup_sects;
415 if (setup_sects == 0)
416 setup_sects = 4;
417
418 kern16_size = (setup_sects + 1) * 512;
419 if (kernel_len < kern16_size) {
420 pr_err("bzImage truncated\n");
421 return ERR_PTR(error: -ENOEXEC);
422 }
423
424 if (cmdline_len > header->cmdline_size) {
425 pr_err("Kernel command line too long\n");
426 return ERR_PTR(error: -EINVAL);
427 }
428
429 /*
430 * In case of crash dump, we will append elfcorehdr=<addr> to
431 * command line. Make sure it does not overflow
432 */
433 if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
434 pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
435 return ERR_PTR(error: -EINVAL);
436 }
437
438#ifdef CONFIG_CRASH_DUMP
439 /* Allocate and load backup region */
440 if (image->type == KEXEC_TYPE_CRASH) {
441 ret = crash_load_segments(image);
442 if (ret)
443 return ERR_PTR(error: ret);
444 }
445#endif
446
447 /*
448 * Load purgatory. For 64bit entry point, purgatory code can be
449 * anywhere.
450 */
451 ret = kexec_load_purgatory(image, kbuf: &pbuf);
452 if (ret) {
453 pr_err("Loading purgatory failed\n");
454 return ERR_PTR(error: ret);
455 }
456
457 kexec_dprintk("Loaded purgatory at 0x%lx\n", pbuf.mem);
458
459
460 /*
461 * Load Bootparams and cmdline and space for efi stuff.
462 *
463 * Allocate memory together for multiple data structures so
464 * that they all can go in single area/segment and we don't
465 * have to create separate segment for each. Keeps things
466 * little bit simple
467 */
468 efi_map_sz = efi_get_runtime_map_size();
469 params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
470 MAX_ELFCOREHDR_STR_LEN;
471 params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
472 kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
473 sizeof(struct setup_data) +
474 sizeof(struct efi_setup_data) +
475 sizeof(struct setup_data) +
476 RNG_SEED_LENGTH;
477
478 if (IS_ENABLED(CONFIG_IMA_KEXEC))
479 kbuf.bufsz += sizeof(struct setup_data) +
480 sizeof(struct ima_setup_data);
481
482 params = kzalloc(size: kbuf.bufsz, GFP_KERNEL);
483 if (!params)
484 return ERR_PTR(error: -ENOMEM);
485 efi_map_offset = params_cmdline_sz;
486 efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
487
488 /* Copy setup header onto bootparams. Documentation/arch/x86/boot.rst */
489 setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
490
491 /* Is there a limit on setup header size? */
492 memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
493
494 kbuf.buffer = params;
495 kbuf.memsz = kbuf.bufsz;
496 kbuf.buf_align = 16;
497 kbuf.buf_min = MIN_BOOTPARAM_ADDR;
498 ret = kexec_add_buffer(kbuf: &kbuf);
499 if (ret)
500 goto out_free_params;
501 bootparam_load_addr = kbuf.mem;
502 kexec_dprintk("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
503 bootparam_load_addr, kbuf.bufsz, kbuf.memsz);
504
505 /* Load kernel */
506 kbuf.buffer = kernel + kern16_size;
507 kbuf.bufsz = kernel_len - kern16_size;
508 kbuf.memsz = PAGE_ALIGN(header->init_size);
509 kbuf.buf_align = header->kernel_alignment;
510 if (header->pref_address < MIN_KERNEL_LOAD_ADDR)
511 kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
512 else
513 kbuf.buf_min = header->pref_address;
514 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
515 ret = kexec_add_buffer(kbuf: &kbuf);
516 if (ret)
517 goto out_free_params;
518 kernel_load_addr = kbuf.mem;
519
520 kexec_dprintk("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
521 kernel_load_addr, kbuf.bufsz, kbuf.memsz);
522
523 /* Load initrd high */
524 if (initrd) {
525 kbuf.buffer = initrd;
526 kbuf.bufsz = kbuf.memsz = initrd_len;
527 kbuf.buf_align = PAGE_SIZE;
528 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
529 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
530 ret = kexec_add_buffer(kbuf: &kbuf);
531 if (ret)
532 goto out_free_params;
533 initrd_load_addr = kbuf.mem;
534
535 kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
536 initrd_load_addr, initrd_len, initrd_len);
537
538 setup_initrd(params, initrd_load_addr, initrd_len);
539 }
540
541 setup_cmdline(image, params, bootparams_load_addr: bootparam_load_addr,
542 cmdline_offset: sizeof(struct boot_params), cmdline, cmdline_len);
543
544 /* bootloader info. Do we need a separate ID for kexec kernel loader? */
545 params->hdr.type_of_loader = 0x0D << 4;
546 params->hdr.loadflags = 0;
547
548 /* Setup purgatory regs for entry */
549 ret = kexec_purgatory_get_set_symbol(image, name: "entry64_regs", buf: &regs64,
550 size: sizeof(regs64), get_value: 1);
551 if (ret)
552 goto out_free_params;
553
554 regs64.rbx = 0; /* Bootstrap Processor */
555 regs64.rsi = bootparam_load_addr;
556 regs64.rip = kernel_load_addr + 0x200;
557 stack = kexec_purgatory_get_symbol_addr(image, name: "stack_end");
558 if (IS_ERR(ptr: stack)) {
559 pr_err("Could not find address of symbol stack_end\n");
560 ret = -EINVAL;
561 goto out_free_params;
562 }
563
564 regs64.rsp = (unsigned long)stack;
565 ret = kexec_purgatory_get_set_symbol(image, name: "entry64_regs", buf: &regs64,
566 size: sizeof(regs64), get_value: 0);
567 if (ret)
568 goto out_free_params;
569
570 ret = setup_boot_parameters(image, params, params_load_addr: bootparam_load_addr,
571 efi_map_offset, efi_map_sz,
572 setup_data_offset: efi_setup_data_offset);
573 if (ret)
574 goto out_free_params;
575
576 /* Allocate loader specific data */
577 ldata = kzalloc(size: sizeof(struct bzimage64_data), GFP_KERNEL);
578 if (!ldata) {
579 ret = -ENOMEM;
580 goto out_free_params;
581 }
582
583 /*
584 * Store pointer to params so that it could be freed after loading
585 * params segment has been loaded and contents have been copied
586 * somewhere else.
587 */
588 ldata->bootparams_buf = params;
589 return ldata;
590
591out_free_params:
592 kfree(objp: params);
593 return ERR_PTR(error: ret);
594}
595
596/* This cleanup function is called after various segments have been loaded */
597static int bzImage64_cleanup(void *loader_data)
598{
599 struct bzimage64_data *ldata = loader_data;
600
601 if (!ldata)
602 return 0;
603
604 kfree(objp: ldata->bootparams_buf);
605 ldata->bootparams_buf = NULL;
606
607 return 0;
608}
609
610const struct kexec_file_ops kexec_bzImage64_ops = {
611 .probe = bzImage64_probe,
612 .load = bzImage64_load,
613 .cleanup = bzImage64_cleanup,
614#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
615 .verify_sig = kexec_kernel_verify_pe_sig,
616#endif
617};
618

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