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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 */
49struct 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
57static 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
69static 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
99static 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
116static 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
137static int
138prepare_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
162static int
163setup_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 (!current_ei->efi_memmap_size)
171 return 0;
172
173 /*
174 * If 1:1 mapping is not enabled, second kernel can not setup EFI
175 * and use EFI run time services. User space will have to pass
176 * acpi_rsdp=<addr> on kernel command line to make second kernel boot
177 * without efi.
178 */
179 if (efi_enabled(EFI_OLD_MEMMAP))
180 return 0;
181
182 ei->efi_loader_signature = current_ei->efi_loader_signature;
183 ei->efi_systab = current_ei->efi_systab;
184 ei->efi_systab_hi = current_ei->efi_systab_hi;
185
186 ei->efi_memdesc_version = current_ei->efi_memdesc_version;
187 ei->efi_memdesc_size = efi_get_runtime_map_desc_size();
188
189 setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
190 efi_map_sz);
191 prepare_add_efi_setup_data(params, params_load_addr,
192 efi_setup_data_offset);
193 return 0;
194}
195#endif /* CONFIG_EFI */
196
197static int
198setup_boot_parameters(struct kimage *image, struct boot_params *params,
199 unsigned long params_load_addr,
200 unsigned int efi_map_offset, unsigned int efi_map_sz,
201 unsigned int efi_setup_data_offset)
202{
203 unsigned int nr_e820_entries;
204 unsigned long long mem_k, start, end;
205 int i, ret = 0;
206
207 /* Get subarch from existing bootparams */
208 params->hdr.hardware_subarch = boot_params.hdr.hardware_subarch;
209
210 /* Copying screen_info will do? */
211 memcpy(¶ms->screen_info, &boot_params.screen_info,
212 sizeof(struct screen_info));
213
214 /* Fill in memsize later */
215 params->screen_info.ext_mem_k = 0;
216 params->alt_mem_k = 0;
217
218 /* Default APM info */
219 memset(¶ms->apm_bios_info, 0, sizeof(params->apm_bios_info));
220
221 /* Default drive info */
222 memset(¶ms->hd0_info, 0, sizeof(params->hd0_info));
223 memset(¶ms->hd1_info, 0, sizeof(params->hd1_info));
224
225 if (image->type == KEXEC_TYPE_CRASH) {
226 ret = crash_setup_memmap_entries(image, params);
227 if (ret)
228 return ret;
229 } else
230 setup_e820_entries(params);
231
232 nr_e820_entries = params->e820_entries;
233
234 for (i = 0; i < nr_e820_entries; i++) {
235 if (params->e820_table[i].type != E820_TYPE_RAM)
236 continue;
237 start = params->e820_table[i].addr;
238 end = params->e820_table[i].addr + params->e820_table[i].size - 1;
239
240 if ((start <= 0x100000) && end > 0x100000) {
241 mem_k = (end >> 10) - (0x100000 >> 10);
242 params->screen_info.ext_mem_k = mem_k;
243 params->alt_mem_k = mem_k;
244 if (mem_k > 0xfc00)
245 params->screen_info.ext_mem_k = 0xfc00; /* 64M*/
246 if (mem_k > 0xffffffff)
247 params->alt_mem_k = 0xffffffff;
248 }
249 }
250
251#ifdef CONFIG_EFI
252 /* Setup EFI state */
253 setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
254 efi_setup_data_offset);
255#endif
256
257 /* Setup EDD info */
258 memcpy(params->eddbuf, boot_params.eddbuf,
259 EDDMAXNR * sizeof(struct edd_info));
260 params->eddbuf_entries = boot_params.eddbuf_entries;
261
262 memcpy(params->edd_mbr_sig_buffer, boot_params.edd_mbr_sig_buffer,
263 EDD_MBR_SIG_MAX * sizeof(unsigned int));
264
265 return ret;
266}
267
268static int bzImage64_probe(const char *buf, unsigned long len)
269{
270 int ret = -ENOEXEC;
271 struct setup_header *header;
272
273 /* kernel should be at least two sectors long */
274 if (len < 2 * 512) {
275 pr_err("File is too short to be a bzImage\n");
276 return ret;
277 }
278
279 header = (struct setup_header *)(buf + offsetof(struct boot_params, hdr));
280 if (memcmp((char *)&header->header, "HdrS", 4) != 0) {
281 pr_err("Not a bzImage\n");
282 return ret;
283 }
284
285 if (header->boot_flag != 0xAA55) {
286 pr_err("No x86 boot sector present\n");
287 return ret;
288 }
289
290 if (header->version < 0x020C) {
291 pr_err("Must be at least protocol version 2.12\n");
292 return ret;
293 }
294
295 if (!(header->loadflags & LOADED_HIGH)) {
296 pr_err("zImage not a bzImage\n");
297 return ret;
298 }
299
300 if (!(header->xloadflags & XLF_KERNEL_64)) {
301 pr_err("Not a bzImage64. XLF_KERNEL_64 is not set.\n");
302 return ret;
303 }
304
305 if (!(header->xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G)) {
306 pr_err("XLF_CAN_BE_LOADED_ABOVE_4G is not set.\n");
307 return ret;
308 }
309
310 /*
311 * Can't handle 32bit EFI as it does not allow loading kernel
312 * above 4G. This should be handled by 32bit bzImage loader
313 */
314 if (efi_enabled(EFI_RUNTIME_SERVICES) && !efi_enabled(EFI_64BIT)) {
315 pr_debug("EFI is 32 bit. Can't load kernel above 4G.\n");
316 return ret;
317 }
318
319 /* I've got a bzImage */
320 pr_debug("It's a relocatable bzImage64\n");
321 ret = 0;
322
323 return ret;
324}
325
326static void *bzImage64_load(struct kimage *image, char *kernel,
327 unsigned long kernel_len, char *initrd,
328 unsigned long initrd_len, char *cmdline,
329 unsigned long cmdline_len)
330{
331
332 struct setup_header *header;
333 int setup_sects, kern16_size, ret = 0;
334 unsigned long setup_header_size, params_cmdline_sz;
335 struct boot_params *params;
336 unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
337 struct bzimage64_data *ldata;
338 struct kexec_entry64_regs regs64;
339 void *stack;
340 unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
341 unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
342 struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX,
343 .top_down = true };
344 struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR,
345 .buf_max = ULONG_MAX, .top_down = true };
346
347 header = (struct setup_header *)(kernel + setup_hdr_offset);
348 setup_sects = header->setup_sects;
349 if (setup_sects == 0)
350 setup_sects = 4;
351
352 kern16_size = (setup_sects + 1) * 512;
353 if (kernel_len < kern16_size) {
354 pr_err("bzImage truncated\n");
355 return ERR_PTR(-ENOEXEC);
356 }
357
358 if (cmdline_len > header->cmdline_size) {
359 pr_err("Kernel command line too long\n");
360 return ERR_PTR(-EINVAL);
361 }
362
363 /*
364 * In case of crash dump, we will append elfcorehdr=<addr> to
365 * command line. Make sure it does not overflow
366 */
367 if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
368 pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
369 return ERR_PTR(-EINVAL);
370 }
371
372 /* Allocate and load backup region */
373 if (image->type == KEXEC_TYPE_CRASH) {
374 ret = crash_load_segments(image);
375 if (ret)
376 return ERR_PTR(ret);
377 }
378
379 /*
380 * Load purgatory. For 64bit entry point, purgatory code can be
381 * anywhere.
382 */
383 ret = kexec_load_purgatory(image, &pbuf);
384 if (ret) {
385 pr_err("Loading purgatory failed\n");
386 return ERR_PTR(ret);
387 }
388
389 pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
390
391
392 /*
393 * Load Bootparams and cmdline and space for efi stuff.
394 *
395 * Allocate memory together for multiple data structures so
396 * that they all can go in single area/segment and we don't
397 * have to create separate segment for each. Keeps things
398 * little bit simple
399 */
400 efi_map_sz = efi_get_runtime_map_size();
401 params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
402 MAX_ELFCOREHDR_STR_LEN;
403 params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
404 kbuf.bufsz = params_cmdline_sz + ALIGN(efi_map_sz, 16) +
405 sizeof(struct setup_data) +
406 sizeof(struct efi_setup_data);
407
408 params = kzalloc(kbuf.bufsz, GFP_KERNEL);
409 if (!params)
410 return ERR_PTR(-ENOMEM);
411 efi_map_offset = params_cmdline_sz;
412 efi_setup_data_offset = efi_map_offset + ALIGN(efi_map_sz, 16);
413
414 /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
415 setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
416
417 /* Is there a limit on setup header size? */
418 memcpy(¶ms->hdr, (kernel + setup_hdr_offset), setup_header_size);
419
420 kbuf.buffer = params;
421 kbuf.memsz = kbuf.bufsz;
422 kbuf.buf_align = 16;
423 kbuf.buf_min = MIN_BOOTPARAM_ADDR;
424 ret = kexec_add_buffer(&kbuf);
425 if (ret)
426 goto out_free_params;
427 bootparam_load_addr = kbuf.mem;
428 pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
429 bootparam_load_addr, kbuf.bufsz, kbuf.bufsz);
430
431 /* Load kernel */
432 kbuf.buffer = kernel + kern16_size;
433 kbuf.bufsz = kernel_len - kern16_size;
434 kbuf.memsz = PAGE_ALIGN(header->init_size);
435 kbuf.buf_align = header->kernel_alignment;
436 kbuf.buf_min = MIN_KERNEL_LOAD_ADDR;
437 ret = kexec_add_buffer(&kbuf);
438 if (ret)
439 goto out_free_params;
440 kernel_load_addr = kbuf.mem;
441
442 pr_debug("Loaded 64bit kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
443 kernel_load_addr, kbuf.bufsz, kbuf.memsz);
444
445 /* Load initrd high */
446 if (initrd) {
447 kbuf.buffer = initrd;
448 kbuf.bufsz = kbuf.memsz = initrd_len;
449 kbuf.buf_align = PAGE_SIZE;
450 kbuf.buf_min = MIN_INITRD_LOAD_ADDR;
451 ret = kexec_add_buffer(&kbuf);
452 if (ret)
453 goto out_free_params;
454 initrd_load_addr = kbuf.mem;
455
456 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
457 initrd_load_addr, initrd_len, initrd_len);
458
459 setup_initrd(params, initrd_load_addr, initrd_len);
460 }
461
462 setup_cmdline(image, params, bootparam_load_addr,
463 sizeof(struct boot_params), cmdline, cmdline_len);
464
465 /* bootloader info. Do we need a separate ID for kexec kernel loader? */
466 params->hdr.type_of_loader = 0x0D << 4;
467 params->hdr.loadflags = 0;
468
469 /* Setup purgatory regs for entry */
470 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
471 sizeof(regs64), 1);
472 if (ret)
473 goto out_free_params;
474
475 regs64.rbx = 0; /* Bootstrap Processor */
476 regs64.rsi = bootparam_load_addr;
477 regs64.rip = kernel_load_addr + 0x200;
478 stack = kexec_purgatory_get_symbol_addr(image, "stack_end");
479 if (IS_ERR(stack)) {
480 pr_err("Could not find address of symbol stack_end\n");
481 ret = -EINVAL;
482 goto out_free_params;
483 }
484
485 regs64.rsp = (unsigned long)stack;
486 ret = kexec_purgatory_get_set_symbol(image, "entry64_regs", ®s64,
487 sizeof(regs64), 0);
488 if (ret)
489 goto out_free_params;
490
491 ret = setup_boot_parameters(image, params, bootparam_load_addr,
492 efi_map_offset, efi_map_sz,
493 efi_setup_data_offset);
494 if (ret)
495 goto out_free_params;
496
497 /* Allocate loader specific data */
498 ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
499 if (!ldata) {
500 ret = -ENOMEM;
501 goto out_free_params;
502 }
503
504 /*
505 * Store pointer to params so that it could be freed after loading
506 * params segment has been loaded and contents have been copied
507 * somewhere else.
508 */
509 ldata->bootparams_buf = params;
510 return ldata;
511
512out_free_params:
513 kfree(params);
514 return ERR_PTR(ret);
515}
516
517/* This cleanup function is called after various segments have been loaded */
518static int bzImage64_cleanup(void *loader_data)
519{
520 struct bzimage64_data *ldata = loader_data;
521
522 if (!ldata)
523 return 0;
524
525 kfree(ldata->bootparams_buf);
526 ldata->bootparams_buf = NULL;
527
528 return 0;
529}
530
531#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
532static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
533{
534 return verify_pefile_signature(kernel, kernel_len,
535 NULL,
536 VERIFYING_KEXEC_PE_SIGNATURE);
537}
538#endif
539
540const struct kexec_file_ops kexec_bzImage64_ops = {
541 .probe = bzImage64_probe,
542 .load = bzImage64_load,
543 .cleanup = bzImage64_cleanup,
544#ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
545 .verify_sig = bzImage64_verify_sig,
546#endif
547};