summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/kexec-bzimage64.c
blob: f03237e3f1927daca018dc2a4dc5e7add1637c96 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Kexec bzImage loader
 *
 * Copyright (C) 2014 Red Hat Inc.
 * Authors:
 *      Vivek Goyal <vgoyal@redhat.com>
 */

#define pr_fmt(fmt)	"kexec-bzImage64: " fmt

#include <linux/string.h>
#include <linux/printk.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/kexec.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/efi.h>
#include <linux/verification.h>

#include <asm/bootparam.h>
#include <asm/setup.h>
#include <asm/crash.h>
#include <asm/efi.h>
#include <asm/e820/api.h>
#include <asm/kexec-bzimage64.h>

#define MAX_ELFCOREHDR_STR_LEN	30	/* elfcorehdr=0x<64bit-value> */

/*
 * Defines lowest physical address for various segments. Not sure where
 * exactly these limits came from. Current bzimage64 loader in kexec-tools
 * uses these so I am retaining it. It can be changed over time as we gain
 * more insight.
 */
#define MIN_PURGATORY_ADDR	0x3000
#define MIN_BOOTPARAM_ADDR	0x3000
#define MIN_KERNEL_LOAD_ADDR	0x100000
#define MIN_INITRD_LOAD_ADDR	0x1000000

/*
 * This is a place holder for all boot loader specific data structure which
 * gets allocated in one call but gets freed much later during cleanup
 * time. Right now there is only one field but it can grow as need be.
 */
struct bzimage64_data {
	/*
	 * Temporary buffer to hold bootparams buffer. This should be
	 * freed once the bootparam segment has been loaded.
	 */
	void *bootparams_buf;
};

static int setup_initrd(struct boot_params *params,
		unsigned long initrd_load_addr, unsigned long initrd_len)
{
	params->hdr.ramdisk_image = initrd_load_addr & 0xffffffffUL;
	params->hdr.ramdisk_size = initrd_len & 0xffffffffUL;

	params->ext_ramdisk_image = initrd_load_addr >> 32;
	params->ext_ramdisk_size = initrd_len >> 32;

	return 0;
}

static int setup_cmdline(struct kimage *image, struct boot_params *params,
			 unsigned long bootparams_load_addr,
			 unsigned long cmdline_offset, char *cmdline,
			 unsigned long cmdline_len)
{
	char *cmdline_ptr = ((char *)params) + cmdline_offset;
	unsigned long cmdline_ptr_phys, len = 0;
	uint32_t cmdline_low_32, cmdline_ext_32;

	if (image->type == KEXEC_TYPE_CRASH) {
		len = sprintf(cmdline_ptr,
			"elfcorehdr=0x%lx ", image->arch.elf_load_addr);
	}
	memcpy(cmdline_ptr + len, cmdline, cmdline_len);
	cmdline_len += len;

	cmdline_ptr[cmdline_len - 1] = '\0';

	pr_debug("Final command line is: %s\n", cmdline_ptr);
	cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
	cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
	cmdline_ext_32 = cmdline_ptr_phys >> 32;

	params->hdr.cmd_line_ptr = cmdline_low_32;
	if (cmdline_ext_32)
		params->ext_cmd_line_ptr = cmdline_ext_32;

	return 0;
}

static int setup_e820_entries(struct boot_params *params)
{
	unsigned int nr_e820_entries;

	nr_e820_entries = e820_table_kexec->nr_entries;

	/* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams setup data */
	if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE)
		nr_e820_entries = E820_MAX_ENTRIES_ZEROPAGE;

	params->e820_entries = nr_e820_entries;
	memcpy(&params->e820_table, &e820_table_kexec->entries, nr_e820_entries*sizeof(struct e820_entry));

	return 0;
}

#ifdef CONFIG_EFI
static int setup_efi_info_memmap(struct boot_params *params,
				  unsigned long params_load_addr,
				  unsigned int efi_map_offset,
				  unsigned int efi_map_sz)
{
	void *efi_map = (void *)params + efi_map_offset;
	unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
	struct efi_info *ei = &params->efi_info;

	if (!efi_map_sz)
		return 0;

	efi_runtime_map_copy(efi_map, efi_map_sz);

	ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
	ei->efi_memmap_hi = efi_map_phys_addr >> 32;
	ei->efi_memmap_size = efi_map_sz;

	return 0;
}

static int
prepare_add_efi_setup_data(struct boot_params *params,
		       unsigned long params_load_addr,
		       unsigned int efi_setup_data_offset)
{
	unsigned long setup_data_phys;
	struct setup_data *sd = (void *)params + efi_setup_data_offset;
	struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);

	esd->fw_vendor = efi.fw_vendor;
	esd->runtime = efi.runtime;
	esd->tables = efi.config_table;
	esd->smbios = efi.smbios;

	sd->type = SETUP_EFI;
	sd->len = sizeof(struct efi_setup_data);

	/* Add setup data */
	setup_data_phys = params_load_addr + efi_setup_data_offset;
	sd->next = params->hdr.setup_data;
	params->hdr.setup_data = setup_data_phys;

	return 0;
}

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)
{
	struct efi_info *current_ei = &boot_params.efi_info;
	struct efi_info *ei = &params->efi_info;

	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return 0;

	if (!current_ei->efi_memmap_size)
		return 0;

	/*
	 * If 1:1 mapping is not enabled, second kernel can not setup EFI
	 * and use EFI run time services. User space will have to pass
	 * acpi_rsdp=<addr> on kernel command line to make second kernel boot
	 * without efi.
	 */
	if (efi_enabled(EFI_OLD_MEMMAP))
		return 0;

	ei->efi_loader_signature = current_ei->efi_loader_signature;
	ei->efi_systab = current_ei->efi_systab;
	ei->efi_systab_hi = current_ei->efi_systab_hi;

	ei->efi_memdesc_version = current_ei->efi_memdesc_version;
	ei->efi_memdesc_size = efi_get_runtime_map_desc_size();

	setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
			      efi_map_sz);
	prepare_add_efi_setup_data(params, params_load_addr,
				   efi_setup_data_offset);
	return 0;
}
#endif /* CONFIG_EFI */

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)
{
	unsigned int nr_e820_entries;
	unsigned long long mem_k, start, end;
	int i, ret = 0;

	/* Get subarch from existing bootparams */
	params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;

	/* Copying screen_info will do? */
	memcpy(&params->screen_info, &boot_params.screen_info,
				sizeof(struct screen_info));

	/* Fill in memsize later */
	params->screen_info.ext_mem_k = 0;
	params->alt_mem_k = 0;

	/* Always fill in RSDP: it is either 0 or a valid value */
	params->acpi_rsdp_addr = boot_params.acpi_rsdp_addr;

	/* Default APM info */
	memset(&params->apm_bios_info, 0, sizeof(params->apm_bios_info));

	/* Default drive info */
	memset(&params->hd0_info, 0, sizeof(params->hd0_info));
	memset(&params->hd1_info, 0, sizeof(params->hd1_info));

	if (image->type == KEXEC_TYPE_CRASH) {
		ret = crash_setup_memmap_entries(image, params);
		if (ret)
			return ret;
	} else
		setup_e820_entries(params);

	nr_e820_entries = params->e820_entries;

	for (i = 0; i < nr_e820_entries; i++) {
		if (params->e820_table[i].type != E820_TYPE_RAM)
			continue;
		start = params->e820_table[i].addr;
		end = params->e820_table[i].addr + params->e820_table[i].size - 1;

		if ((start <= 0x100000) && end > 0x100000) {
			mem_k = (end >> 10) - (0x100000 >> 10);
			params->screen_info.ext_mem_k = mem_k;
			params->alt_mem_k = mem_k;
			if (mem_k > 0xfc00)
				params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
			if (mem_k > 0xffffffff)
				params->alt_mem_k = 0xffffffff;
		}
	}

#ifdef CONFIG_EFI
	/* Setup EFI state */
	setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
			efi_setup_data_offset);
#endif
	/* Setup EDD info */
	memcpy(params->eddbuf, boot_params.eddbuf,
				EDDMAXNR * sizeof(struct edd_info));
	params->eddbuf_entries = boot_params.eddbuf_entries;

	memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
	       EDD_MBR_SIG_MAX * sizeof(unsigned int));

	return ret;
}

static int bzImage64_probe(const char *buf, unsigned long len)
{
	int ret = -ENOEXEC;
	struct setup_header *header;

	/* kernel should be at least two sectors long */
	if (len < 2 * 512) {
		pr_err("File is too short to be a bzImage\n");
		return ret;
	}

	header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
	if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
		pr_err("Not a bzImage\n");
		return ret;
	}

	if (header->boot_flag != 0xAA55) {
		pr_err("No x86 boot sector present\n");
		return ret;
	}

	if (header->version < 0x020C) {
		pr_err("Must be at least protocol version 2.12\n");
		return ret;
	}

	if (!(header->loadflags & LOADED_HIGH)) {
		pr_err("zImage not a bzImage\n");
		return ret;
	}

	if (!(header->xloadflags & XLF_KERNEL_64)) {
		pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
		return ret;
	}

	if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
		pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
		return ret;
	}

	/*
	 * Can't handle 32bit EFI as it does not allow loading kernel
	 * above 4G. This should be handled by 32bit bzImage loader
	 */
	if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
		pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
		return ret;
	}

	/* I've got a bzImage */
	pr_debug("It's a relocatable bzImage64\n");
	ret = 0;

	return ret;
}

static void *bzImage64_load(struct kimage *image, char *kernel,
			    unsigned long kernel_len, char *initrd,
			    unsigned long initrd_len, char *cmdline,
			    unsigned long cmdline_len)
{

	struct setup_header *header;
	int setup_sects, kern16_size, ret = 0;
	unsigned long setup_header_size, params_cmdline_sz;
	struct boot_params *params;
	unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
	struct bzimage64_data *ldata;
	struct kexec_entry64_regs regs64;
	void *stack;
	unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
	unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
	struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
				  .top_down = true };
	struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
				  .buf_max = ULONG_MAX, .top_down = true };

	header = (struct setup_header *)(kernel + setup_hdr_offset);
	setup_sects = header->setup_sects;
	if (setup_sects == 0)
		setup_sects = 4;

	kern16_size = (setup_sects + 1) * 512;
	if (kernel_len < kern16_size) {
		pr_err("bzImage truncated\n");
		return ERR_PTR(-ENOEXEC);
	}

	if (cmdline_len > header->cmdline_size) {
		pr_err("Kernel command line too long\n");
		return ERR_PTR(-EINVAL);
	}

	/*
	 * In case of crash dump, we will append elfcorehdr=<addr> to
	 * command line. Make sure it does not overflow
	 */
	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
		pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
		return ERR_PTR(-EINVAL);
	}

	/* Allocate and load backup region */
	if (image->type == KEXEC_TYPE_CRASH) {
		ret = crash_load_segments(image);
		if (ret)
			return ERR_PTR(ret);
	}

	/*
	 * Load purgatory. For 64bit entry point, purgatory  code can be
	 * anywhere.
	 */
	ret = kexec_load_purgatory(image, &pbuf);
	if (ret) {
		pr_err("Loading purgatory failed\n");
		return ERR_PTR(ret);
	}

	pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);


	/*
	 * Load Bootparams and cmdline and space for efi stuff.
	 *
	 * Allocate memory together for multiple data structures so
	 * that they all can go in single area/segment and we don't
	 * have to create separate segment for each. Keeps things
	 * little bit simple
	 */
	efi_map_sz = efi_get_runtime_map_size();
	params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
				MAX_ELFCOREHDR_STR_LEN;
	params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
	kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
				sizeof(struct setup_data) +
				sizeof(struct efi_setup_data);

	params = kzalloc(kbuf.bufsz, GFP_KERNEL);
	if (!params)
		return ERR_PTR(-ENOMEM);
	efi_map_offset = params_cmdline_sz;
	efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);

	/* Copy setup header onto bootparams. Documentation/x86/boot.txt */
	setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;

	/* Is there a limit on setup header size? */
	memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);

	kbuf.buffer = params;
	kbuf.memsz = kbuf.bufsz;
	kbuf.buf_align = 16;
	kbuf.buf_min = MIN_BOOTPARAM_ADDR;
	ret = kexec_add_buffer(&kbuf);
	if (ret)
		goto out_free_params;
	bootparam_load_addr = kbuf.mem;
	pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
		 bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);

	/* Load kernel */
	kbuf.buffer = kernel + kern16_size;
	kbuf.bufsz =  kernel_len - kern16_size;
	kbuf.memsz = PAGE_ALIGN(header->init_size);
	kbuf.buf_align = header->kernel_alignment;
	kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
	ret = kexec_add_buffer(&kbuf);
	if (ret)
		goto out_free_params;
	kernel_load_addr = kbuf.mem;

	pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
		 kernel_load_addr, kbuf.bufsz, kbuf.memsz);

	/* Load initrd high */
	if (initrd) {
		kbuf.buffer = initrd;
		kbuf.bufsz = kbuf.memsz = initrd_len;
		kbuf.buf_align = PAGE_SIZE;
		kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
		ret = kexec_add_buffer(&kbuf);
		if (ret)
			goto out_free_params;
		initrd_load_addr = kbuf.mem;

		pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
				initrd_load_addr, initrd_len, initrd_len);

		setup_initrd(params, initrd_load_addr, initrd_len);
	}

	setup_cmdline(image, params, bootparam_load_addr,
		      sizeof(struct boot_params), cmdline, cmdline_len);

	/* bootloader info. Do we need a separate ID for kexec kernel loader? */
	params->hdr.type_of_loader = 0x0D << 4;
	params->hdr.loadflags = 0;

	/* Setup purgatory regs for entry */
	ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
					     sizeof(regs64), 1);
	if (ret)
		goto out_free_params;

	regs64.rbx = 0; /* Bootstrap Processor */
	regs64.rsi = bootparam_load_addr;
	regs64.rip = kernel_load_addr + 0x200;
	stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
	if (IS_ERR(stack)) {
		pr_err("Could not find address of symbol stack_end\n");
		ret = -EINVAL;
		goto out_free_params;
	}

	regs64.rsp = (unsigned long)stack;
	ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", &regs64,
					     sizeof(regs64), 0);
	if (ret)
		goto out_free_params;

	ret = setup_boot_parameters(image, params, bootparam_load_addr,
				    efi_map_offset, efi_map_sz,
				    efi_setup_data_offset);
	if (ret)
		goto out_free_params;

	/* Allocate loader specific data */
	ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
	if (!ldata) {
		ret = -ENOMEM;
		goto out_free_params;
	}

	/*
	 * Store pointer to params so that it could be freed after loading
	 * params segment has been loaded and contents have been copied
	 * somewhere else.
	 */
	ldata->bootparams_buf = params;
	return ldata;

out_free_params:
	kfree(params);
	return ERR_PTR(ret);
}

/* This cleanup function is called after various segments have been loaded */
static int bzImage64_cleanup(void *loader_data)
{
	struct bzimage64_data *ldata = loader_data;

	if (!ldata)
		return 0;

	kfree(ldata->bootparams_buf);
	ldata->bootparams_buf = NULL;

	return 0;
}

#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
{
	int ret;

	ret = verify_pefile_signature(kernel, kernel_len,
				      VERIFY_USE_SECONDARY_KEYRING,
				      VERIFYING_KEXEC_PE_SIGNATURE);
	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
		ret = verify_pefile_signature(kernel, kernel_len,
					      VERIFY_USE_PLATFORM_KEYRING,
					      VERIFYING_KEXEC_PE_SIGNATURE);
	}
	return ret;
}
#endif

const struct kexec_file_ops kexec_bzImage64_ops = {
	.probe = bzImage64_probe,
	.load = bzImage64_load,
	.cleanup = bzImage64_cleanup,
#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
	.verify_sig = bzImage64_verify_sig,
#endif
};