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8
9#define pr_fmt(fmt) "kexec: " fmt
10
11#include <linux/mm.h>
12#include <linux/kexec.h>
13#include <linux/string.h>
14#include <linux/gfp.h>
15#include <linux/reboot.h>
16#include <linux/numa.h>
17#include <linux/ftrace.h>
18#include <linux/io.h>
19#include <linux/suspend.h>
20
21#include <asm/init.h>
22#include <asm/pgtable.h>
23#include <asm/tlbflush.h>
24#include <asm/mmu_context.h>
25#include <asm/io_apic.h>
26#include <asm/debugreg.h>
27#include <asm/kexec-bzimage64.h>
28
29#ifdef CONFIG_KEXEC_FILE
30static struct kexec_file_ops *kexec_file_loaders[] = {
31 &kexec_bzImage64_ops,
32};
33#endif
34
35static void free_transition_pgtable(struct kimage *image)
36{
37 free_page((unsigned long)image->arch.pud);
38 free_page((unsigned long)image->arch.pmd);
39 free_page((unsigned long)image->arch.pte);
40}
41
42static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
43{
44 pud_t *pud;
45 pmd_t *pmd;
46 pte_t *pte;
47 unsigned long vaddr, paddr;
48 int result = -ENOMEM;
49
50 vaddr = (unsigned long)relocate_kernel;
51 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
52 pgd += pgd_index(vaddr);
53 if (!pgd_present(*pgd)) {
54 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
55 if (!pud)
56 goto err;
57 image->arch.pud = pud;
58 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
59 }
60 pud = pud_offset(pgd, vaddr);
61 if (!pud_present(*pud)) {
62 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
63 if (!pmd)
64 goto err;
65 image->arch.pmd = pmd;
66 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
67 }
68 pmd = pmd_offset(pud, vaddr);
69 if (!pmd_present(*pmd)) {
70 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
71 if (!pte)
72 goto err;
73 image->arch.pte = pte;
74 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
75 }
76 pte = pte_offset_kernel(pmd, vaddr);
77 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
78 return 0;
79err:
80 free_transition_pgtable(image);
81 return result;
82}
83
84static void *alloc_pgt_page(void *data)
85{
86 struct kimage *image = (struct kimage *)data;
87 struct page *page;
88 void *p = NULL;
89
90 page = kimage_alloc_control_pages(image, 0);
91 if (page) {
92 p = page_address(page);
93 clear_page(p);
94 }
95
96 return p;
97}
98
99static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
100{
101 struct x86_mapping_info info = {
102 .alloc_pgt_page = alloc_pgt_page,
103 .context = image,
104 .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
105 };
106 unsigned long mstart, mend;
107 pgd_t *level4p;
108 int result;
109 int i;
110
111 level4p = (pgd_t *)__va(start_pgtable);
112 clear_page(level4p);
113 for (i = 0; i < nr_pfn_mapped; i++) {
114 mstart = pfn_mapped[i].start << PAGE_SHIFT;
115 mend = pfn_mapped[i].end << PAGE_SHIFT;
116
117 result = kernel_ident_mapping_init(&info,
118 level4p, mstart, mend);
119 if (result)
120 return result;
121 }
122
123
124
125
126
127
128
129 for (i = 0; i < image->nr_segments; i++) {
130 mstart = image->segment[i].mem;
131 mend = mstart + image->segment[i].memsz;
132
133 result = kernel_ident_mapping_init(&info,
134 level4p, mstart, mend);
135
136 if (result)
137 return result;
138 }
139
140 return init_transition_pgtable(image, level4p);
141}
142
143static void set_idt(void *newidt, u16 limit)
144{
145 struct desc_ptr curidt;
146
147
148 curidt.size = limit;
149 curidt.address = (unsigned long)newidt;
150
151 __asm__ __volatile__ (
152 "lidtq %0\n"
153 : : "m" (curidt)
154 );
155};
156
157
158static void set_gdt(void *newgdt, u16 limit)
159{
160 struct desc_ptr curgdt;
161
162
163 curgdt.size = limit;
164 curgdt.address = (unsigned long)newgdt;
165
166 __asm__ __volatile__ (
167 "lgdtq %0\n"
168 : : "m" (curgdt)
169 );
170};
171
172static void load_segments(void)
173{
174 __asm__ __volatile__ (
175 "\tmovl %0,%%ds\n"
176 "\tmovl %0,%%es\n"
177 "\tmovl %0,%%ss\n"
178 "\tmovl %0,%%fs\n"
179 "\tmovl %0,%%gs\n"
180 : : "a" (__KERNEL_DS) : "memory"
181 );
182}
183
184#ifdef CONFIG_KEXEC_FILE
185
186static int arch_update_purgatory(struct kimage *image)
187{
188 int ret = 0;
189
190 if (!image->file_mode)
191 return 0;
192
193
194 if (image->type == KEXEC_TYPE_CRASH) {
195 ret = kexec_purgatory_get_set_symbol(image, "backup_dest",
196 &image->arch.backup_load_addr,
197 sizeof(image->arch.backup_load_addr), 0);
198 if (ret)
199 return ret;
200
201 ret = kexec_purgatory_get_set_symbol(image, "backup_src",
202 &image->arch.backup_src_start,
203 sizeof(image->arch.backup_src_start), 0);
204 if (ret)
205 return ret;
206
207 ret = kexec_purgatory_get_set_symbol(image, "backup_sz",
208 &image->arch.backup_src_sz,
209 sizeof(image->arch.backup_src_sz), 0);
210 if (ret)
211 return ret;
212 }
213
214 return ret;
215}
216#else
217static inline int arch_update_purgatory(struct kimage *image)
218{
219 return 0;
220}
221#endif
222
223int machine_kexec_prepare(struct kimage *image)
224{
225 unsigned long start_pgtable;
226 int result;
227
228
229 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
230
231
232 result = init_pgtable(image, start_pgtable);
233 if (result)
234 return result;
235
236
237 result = arch_update_purgatory(image);
238 if (result)
239 return result;
240
241 return 0;
242}
243
244void machine_kexec_cleanup(struct kimage *image)
245{
246 free_transition_pgtable(image);
247}
248
249
250
251
252
253void machine_kexec(struct kimage *image)
254{
255 unsigned long page_list[PAGES_NR];
256 void *control_page;
257 int save_ftrace_enabled;
258
259#ifdef CONFIG_KEXEC_JUMP
260 if (image->preserve_context)
261 save_processor_state();
262#endif
263
264 save_ftrace_enabled = __ftrace_enabled_save();
265
266
267 local_irq_disable();
268 hw_breakpoint_disable();
269
270 if (image->preserve_context) {
271#ifdef CONFIG_X86_IO_APIC
272
273
274
275
276
277
278
279 disable_IO_APIC();
280#endif
281 }
282
283 control_page = page_address(image->control_code_page) + PAGE_SIZE;
284 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
285
286 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
287 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
288 page_list[PA_TABLE_PAGE] =
289 (unsigned long)__pa(page_address(image->control_code_page));
290
291 if (image->type == KEXEC_TYPE_DEFAULT)
292 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
293 << PAGE_SHIFT);
294
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304
305 load_segments();
306
307
308
309
310 set_gdt(phys_to_virt(0), 0);
311 set_idt(phys_to_virt(0), 0);
312
313
314 image->start = relocate_kernel((unsigned long)image->head,
315 (unsigned long)page_list,
316 image->start,
317 image->preserve_context);
318
319#ifdef CONFIG_KEXEC_JUMP
320 if (image->preserve_context)
321 restore_processor_state();
322#endif
323
324 __ftrace_enabled_restore(save_ftrace_enabled);
325}
326
327void arch_crash_save_vmcoreinfo(void)
328{
329 VMCOREINFO_SYMBOL(phys_base);
330 VMCOREINFO_SYMBOL(init_level4_pgt);
331
332#ifdef CONFIG_NUMA
333 VMCOREINFO_SYMBOL(node_data);
334 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
335#endif
336 vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
337 (unsigned long)&_text - __START_KERNEL);
338}
339
340
341
342#ifdef CONFIG_KEXEC_FILE
343int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
344 unsigned long buf_len)
345{
346 int i, ret = -ENOEXEC;
347 struct kexec_file_ops *fops;
348
349 for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
350 fops = kexec_file_loaders[i];
351 if (!fops || !fops->probe)
352 continue;
353
354 ret = fops->probe(buf, buf_len);
355 if (!ret) {
356 image->fops = fops;
357 return ret;
358 }
359 }
360
361 return ret;
362}
363
364void *arch_kexec_kernel_image_load(struct kimage *image)
365{
366 vfree(image->arch.elf_headers);
367 image->arch.elf_headers = NULL;
368
369 if (!image->fops || !image->fops->load)
370 return ERR_PTR(-ENOEXEC);
371
372 return image->fops->load(image, image->kernel_buf,
373 image->kernel_buf_len, image->initrd_buf,
374 image->initrd_buf_len, image->cmdline_buf,
375 image->cmdline_buf_len);
376}
377
378int arch_kimage_file_post_load_cleanup(struct kimage *image)
379{
380 if (!image->fops || !image->fops->cleanup)
381 return 0;
382
383 return image->fops->cleanup(image->image_loader_data);
384}
385
386int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
387 unsigned long kernel_len)
388{
389 if (!image->fops || !image->fops->verify_sig) {
390 pr_debug("kernel loader does not support signature verification.");
391 return -EKEYREJECTED;
392 }
393
394 return image->fops->verify_sig(kernel, kernel_len);
395}
396
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404
405
406int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
407 Elf64_Shdr *sechdrs, unsigned int relsec)
408{
409 unsigned int i;
410 Elf64_Rela *rel;
411 Elf64_Sym *sym;
412 void *location;
413 Elf64_Shdr *section, *symtabsec;
414 unsigned long address, sec_base, value;
415 const char *strtab, *name, *shstrtab;
416
417
418
419
420
421 rel = (void *)sechdrs[relsec].sh_offset;
422
423
424 section = &sechdrs[sechdrs[relsec].sh_info];
425
426 pr_debug("Applying relocate section %u to %u\n", relsec,
427 sechdrs[relsec].sh_info);
428
429
430 symtabsec = &sechdrs[sechdrs[relsec].sh_link];
431
432
433 if (symtabsec->sh_link >= ehdr->e_shnum) {
434
435 pr_err("Invalid string table section index %d\n",
436 symtabsec->sh_link);
437 return -ENOEXEC;
438 }
439
440 strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;
441
442
443 shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;
444
445 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
446
447
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452
453
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456
457 location = (void *)(section->sh_offset + rel[i].r_offset);
458
459
460 address = section->sh_addr + rel[i].r_offset;
461
462
463
464
465
466
467
468 sym = (Elf64_Sym *)symtabsec->sh_offset +
469 ELF64_R_SYM(rel[i].r_info);
470
471 if (sym->st_name)
472 name = strtab + sym->st_name;
473 else
474 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
475
476 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
477 name, sym->st_info, sym->st_shndx, sym->st_value,
478 sym->st_size);
479
480 if (sym->st_shndx == SHN_UNDEF) {
481 pr_err("Undefined symbol: %s\n", name);
482 return -ENOEXEC;
483 }
484
485 if (sym->st_shndx == SHN_COMMON) {
486 pr_err("symbol '%s' in common section\n", name);
487 return -ENOEXEC;
488 }
489
490 if (sym->st_shndx == SHN_ABS)
491 sec_base = 0;
492 else if (sym->st_shndx >= ehdr->e_shnum) {
493 pr_err("Invalid section %d for symbol %s\n",
494 sym->st_shndx, name);
495 return -ENOEXEC;
496 } else
497 sec_base = sechdrs[sym->st_shndx].sh_addr;
498
499 value = sym->st_value;
500 value += sec_base;
501 value += rel[i].r_addend;
502
503 switch (ELF64_R_TYPE(rel[i].r_info)) {
504 case R_X86_64_NONE:
505 break;
506 case R_X86_64_64:
507 *(u64 *)location = value;
508 break;
509 case R_X86_64_32:
510 *(u32 *)location = value;
511 if (value != *(u32 *)location)
512 goto overflow;
513 break;
514 case R_X86_64_32S:
515 *(s32 *)location = value;
516 if ((s64)value != *(s32 *)location)
517 goto overflow;
518 break;
519 case R_X86_64_PC32:
520 value -= (u64)address;
521 *(u32 *)location = value;
522 break;
523 default:
524 pr_err("Unknown rela relocation: %llu\n",
525 ELF64_R_TYPE(rel[i].r_info));
526 return -ENOEXEC;
527 }
528 }
529 return 0;
530
531overflow:
532 pr_err("Overflow in relocation type %d value 0x%lx\n",
533 (int)ELF64_R_TYPE(rel[i].r_info), value);
534 return -ENOEXEC;
535}
536#endif
537