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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * handle transition of Linux booting another kernel
4 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
5 */
6
7#define pr_fmt(fmt) "kexec: " fmt
8
9#include <linux/mm.h>
10#include <linux/kexec.h>
11#include <linux/string.h>
12#include <linux/gfp.h>
13#include <linux/reboot.h>
14#include <linux/numa.h>
15#include <linux/ftrace.h>
16#include <linux/io.h>
17#include <linux/suspend.h>
18#include <linux/vmalloc.h>
19#include <linux/efi.h>
20#include <linux/cc_platform.h>
21
22#include <asm/init.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#include <asm/setup.h>
29#include <asm/set_memory.h>
30#include <asm/cpu.h>
31#include <asm/efi.h>
32
33#ifdef CONFIG_ACPI
34/*
35 * Used while adding mapping for ACPI tables.
36 * Can be reused when other iomem regions need be mapped
37 */
38struct init_pgtable_data {
39 struct x86_mapping_info *info;
40 pgd_t *level4p;
41};
42
43static int mem_region_callback(struct resource *res, void *arg)
44{
45 struct init_pgtable_data *data = arg;
46
47 return kernel_ident_mapping_init(data->info, data->level4p,
48 res->start, res->end + 1);
49}
50
51static int
52map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p)
53{
54 struct init_pgtable_data data;
55 unsigned long flags;
56 int ret;
57
58 data.info = info;
59 data.level4p = level4p;
60 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
61
62 ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
63 &data, mem_region_callback);
64 if (ret && ret != -EINVAL)
65 return ret;
66
67 /* ACPI tables could be located in ACPI Non-volatile Storage region */
68 ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
69 &data, mem_region_callback);
70 if (ret && ret != -EINVAL)
71 return ret;
72
73 return 0;
74}
75#else
76static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; }
77#endif
78
79#ifdef CONFIG_KEXEC_FILE
80const struct kexec_file_ops * const kexec_file_loaders[] = {
81 &kexec_bzImage64_ops,
82 NULL
83};
84#endif
85
86static int
87map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p)
88{
89#ifdef CONFIG_EFI
90 unsigned long mstart, mend;
91 void *kaddr;
92 int ret;
93
94 if (!efi_enabled(EFI_BOOT))
95 return 0;
96
97 mstart = (boot_params.efi_info.efi_systab |
98 ((u64)boot_params.efi_info.efi_systab_hi<<32));
99
100 if (efi_enabled(EFI_64BIT))
101 mend = mstart + sizeof(efi_system_table_64_t);
102 else
103 mend = mstart + sizeof(efi_system_table_32_t);
104
105 if (!mstart)
106 return 0;
107
108 ret = kernel_ident_mapping_init(info, level4p, mstart, mend);
109 if (ret)
110 return ret;
111
112 kaddr = memremap(mstart, mend - mstart, MEMREMAP_WB);
113 if (!kaddr) {
114 pr_err("Could not map UEFI system table\n");
115 return -ENOMEM;
116 }
117
118 mstart = efi_config_table;
119
120 if (efi_enabled(EFI_64BIT)) {
121 efi_system_table_64_t *stbl = (efi_system_table_64_t *)kaddr;
122
123 mend = mstart + sizeof(efi_config_table_64_t) * stbl->nr_tables;
124 } else {
125 efi_system_table_32_t *stbl = (efi_system_table_32_t *)kaddr;
126
127 mend = mstart + sizeof(efi_config_table_32_t) * stbl->nr_tables;
128 }
129
130 memunmap(kaddr);
131
132 return kernel_ident_mapping_init(info, level4p, mstart, mend);
133#endif
134 return 0;
135}
136
137static void free_transition_pgtable(struct kimage *image)
138{
139 free_page((unsigned long)image->arch.p4d);
140 image->arch.p4d = NULL;
141 free_page((unsigned long)image->arch.pud);
142 image->arch.pud = NULL;
143 free_page((unsigned long)image->arch.pmd);
144 image->arch.pmd = NULL;
145 free_page((unsigned long)image->arch.pte);
146 image->arch.pte = NULL;
147}
148
149static int init_transition_pgtable(struct kimage *image, pgd_t *pgd,
150 unsigned long control_page)
151{
152 pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
153 unsigned long vaddr, paddr;
154 int result = -ENOMEM;
155 p4d_t *p4d;
156 pud_t *pud;
157 pmd_t *pmd;
158 pte_t *pte;
159
160 vaddr = (unsigned long)relocate_kernel;
161 paddr = control_page;
162 pgd += pgd_index(vaddr);
163 if (!pgd_present(*pgd)) {
164 p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
165 if (!p4d)
166 goto err;
167 image->arch.p4d = p4d;
168 set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));
169 }
170 p4d = p4d_offset(pgd, vaddr);
171 if (!p4d_present(*p4d)) {
172 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
173 if (!pud)
174 goto err;
175 image->arch.pud = pud;
176 set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
177 }
178 pud = pud_offset(p4d, vaddr);
179 if (!pud_present(*pud)) {
180 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
181 if (!pmd)
182 goto err;
183 image->arch.pmd = pmd;
184 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
185 }
186 pmd = pmd_offset(pud, vaddr);
187 if (!pmd_present(*pmd)) {
188 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
189 if (!pte)
190 goto err;
191 image->arch.pte = pte;
192 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
193 }
194 pte = pte_offset_kernel(pmd, vaddr);
195
196 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
197 prot = PAGE_KERNEL_EXEC;
198
199 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
200 return 0;
201err:
202 return result;
203}
204
205static void *alloc_pgt_page(void *data)
206{
207 struct kimage *image = (struct kimage *)data;
208 struct page *page;
209 void *p = NULL;
210
211 page = kimage_alloc_control_pages(image, 0);
212 if (page) {
213 p = page_address(page);
214 clear_page(p);
215 }
216
217 return p;
218}
219
220static int init_pgtable(struct kimage *image, unsigned long control_page)
221{
222 struct x86_mapping_info info = {
223 .alloc_pgt_page = alloc_pgt_page,
224 .context = image,
225 .page_flag = __PAGE_KERNEL_LARGE_EXEC,
226 .kernpg_flag = _KERNPG_TABLE_NOENC,
227 };
228 unsigned long mstart, mend;
229 int result;
230 int i;
231
232 image->arch.pgd = alloc_pgt_page(image);
233 if (!image->arch.pgd)
234 return -ENOMEM;
235
236 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
237 info.page_flag |= _PAGE_ENC;
238 info.kernpg_flag |= _PAGE_ENC;
239 }
240
241 if (direct_gbpages)
242 info.direct_gbpages = true;
243
244 for (i = 0; i < nr_pfn_mapped; i++) {
245 mstart = pfn_mapped[i].start << PAGE_SHIFT;
246 mend = pfn_mapped[i].end << PAGE_SHIFT;
247
248 result = kernel_ident_mapping_init(&info, image->arch.pgd,
249 mstart, mend);
250 if (result)
251 return result;
252 }
253
254 /*
255 * segments's mem ranges could be outside 0 ~ max_pfn,
256 * for example when jump back to original kernel from kexeced kernel.
257 * or first kernel is booted with user mem map, and second kernel
258 * could be loaded out of that range.
259 */
260 for (i = 0; i < image->nr_segments; i++) {
261 mstart = image->segment[i].mem;
262 mend = mstart + image->segment[i].memsz;
263
264 result = kernel_ident_mapping_init(&info, image->arch.pgd,
265 mstart, mend);
266
267 if (result)
268 return result;
269 }
270
271 /*
272 * Prepare EFI systab and ACPI tables for kexec kernel since they are
273 * not covered by pfn_mapped.
274 */
275 result = map_efi_systab(&info, image->arch.pgd);
276 if (result)
277 return result;
278
279 result = map_acpi_tables(&info, image->arch.pgd);
280 if (result)
281 return result;
282
283 /*
284 * This must be last because the intermediate page table pages it
285 * allocates will not be control pages and may overlap the image.
286 */
287 return init_transition_pgtable(image, image->arch.pgd, control_page);
288}
289
290static void load_segments(void)
291{
292 __asm__ __volatile__ (
293 "\tmovl %0,%%ds\n"
294 "\tmovl %0,%%es\n"
295 "\tmovl %0,%%ss\n"
296 "\tmovl %0,%%fs\n"
297 "\tmovl %0,%%gs\n"
298 : : "a" (__KERNEL_DS) : "memory"
299 );
300}
301
302int machine_kexec_prepare(struct kimage *image)
303{
304 unsigned long control_page;
305 int result;
306
307 /* Calculate the offsets */
308 control_page = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
309
310 /* Setup the identity mapped 64bit page table */
311 result = init_pgtable(image, control_page);
312 if (result)
313 return result;
314
315 return 0;
316}
317
318void machine_kexec_cleanup(struct kimage *image)
319{
320 free_transition_pgtable(image);
321}
322
323/*
324 * Do not allocate memory (or fail in any way) in machine_kexec().
325 * We are past the point of no return, committed to rebooting now.
326 */
327void machine_kexec(struct kimage *image)
328{
329 unsigned long page_list[PAGES_NR];
330 unsigned int host_mem_enc_active;
331 int save_ftrace_enabled;
332 void *control_page;
333
334 /*
335 * This must be done before load_segments() since if call depth tracking
336 * is used then GS must be valid to make any function calls.
337 */
338 host_mem_enc_active = cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT);
339
340#ifdef CONFIG_KEXEC_JUMP
341 if (image->preserve_context)
342 save_processor_state();
343#endif
344
345 save_ftrace_enabled = __ftrace_enabled_save();
346
347 /* Interrupts aren't acceptable while we reboot */
348 local_irq_disable();
349 hw_breakpoint_disable();
350 cet_disable();
351
352 if (image->preserve_context) {
353#ifdef CONFIG_X86_IO_APIC
354 /*
355 * We need to put APICs in legacy mode so that we can
356 * get timer interrupts in second kernel. kexec/kdump
357 * paths already have calls to restore_boot_irq_mode()
358 * in one form or other. kexec jump path also need one.
359 */
360 clear_IO_APIC();
361 restore_boot_irq_mode();
362#endif
363 }
364
365 control_page = page_address(image->control_code_page);
366 __memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
367
368 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
369 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
370 page_list[PA_TABLE_PAGE] = (unsigned long)__pa(image->arch.pgd);
371
372 if (image->type == KEXEC_TYPE_DEFAULT)
373 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
374 << PAGE_SHIFT);
375
376 /*
377 * The segment registers are funny things, they have both a
378 * visible and an invisible part. Whenever the visible part is
379 * set to a specific selector, the invisible part is loaded
380 * with from a table in memory. At no other time is the
381 * descriptor table in memory accessed.
382 *
383 * I take advantage of this here by force loading the
384 * segments, before I zap the gdt with an invalid value.
385 */
386 load_segments();
387 /*
388 * The gdt & idt are now invalid.
389 * If you want to load them you must set up your own idt & gdt.
390 */
391 native_idt_invalidate();
392 native_gdt_invalidate();
393
394 /* now call it */
395 image->start = relocate_kernel((unsigned long)image->head,
396 (unsigned long)page_list,
397 image->start,
398 image->preserve_context,
399 host_mem_enc_active);
400
401#ifdef CONFIG_KEXEC_JUMP
402 if (image->preserve_context)
403 restore_processor_state();
404#endif
405
406 __ftrace_enabled_restore(save_ftrace_enabled);
407}
408
409/* arch-dependent functionality related to kexec file-based syscall */
410
411#ifdef CONFIG_KEXEC_FILE
412/*
413 * Apply purgatory relocations.
414 *
415 * @pi: Purgatory to be relocated.
416 * @section: Section relocations applying to.
417 * @relsec: Section containing RELAs.
418 * @symtabsec: Corresponding symtab.
419 *
420 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
421 */
422int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
423 Elf_Shdr *section, const Elf_Shdr *relsec,
424 const Elf_Shdr *symtabsec)
425{
426 unsigned int i;
427 Elf64_Rela *rel;
428 Elf64_Sym *sym;
429 void *location;
430 unsigned long address, sec_base, value;
431 const char *strtab, *name, *shstrtab;
432 const Elf_Shdr *sechdrs;
433
434 /* String & section header string table */
435 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
436 strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
437 shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
438
439 rel = (void *)pi->ehdr + relsec->sh_offset;
440
441 pr_debug("Applying relocate section %s to %u\n",
442 shstrtab + relsec->sh_name, relsec->sh_info);
443
444 for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {
445
446 /*
447 * rel[i].r_offset contains byte offset from beginning
448 * of section to the storage unit affected.
449 *
450 * This is location to update. This is temporary buffer
451 * where section is currently loaded. This will finally be
452 * loaded to a different address later, pointed to by
453 * ->sh_addr. kexec takes care of moving it
454 * (kexec_load_segment()).
455 */
456 location = pi->purgatory_buf;
457 location += section->sh_offset;
458 location += rel[i].r_offset;
459
460 /* Final address of the location */
461 address = section->sh_addr + rel[i].r_offset;
462
463 /*
464 * rel[i].r_info contains information about symbol table index
465 * w.r.t which relocation must be made and type of relocation
466 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
467 * these respectively.
468 */
469 sym = (void *)pi->ehdr + symtabsec->sh_offset;
470 sym += ELF64_R_SYM(rel[i].r_info);
471
472 if (sym->st_name)
473 name = strtab + sym->st_name;
474 else
475 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
476
477 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
478 name, sym->st_info, sym->st_shndx, sym->st_value,
479 sym->st_size);
480
481 if (sym->st_shndx == SHN_UNDEF) {
482 pr_err("Undefined symbol: %s\n", name);
483 return -ENOEXEC;
484 }
485
486 if (sym->st_shndx == SHN_COMMON) {
487 pr_err("symbol '%s' in common section\n", name);
488 return -ENOEXEC;
489 }
490
491 if (sym->st_shndx == SHN_ABS)
492 sec_base = 0;
493 else if (sym->st_shndx >= pi->ehdr->e_shnum) {
494 pr_err("Invalid section %d for symbol %s\n",
495 sym->st_shndx, name);
496 return -ENOEXEC;
497 } else
498 sec_base = pi->sechdrs[sym->st_shndx].sh_addr;
499
500 value = sym->st_value;
501 value += sec_base;
502 value += rel[i].r_addend;
503
504 switch (ELF64_R_TYPE(rel[i].r_info)) {
505 case R_X86_64_NONE:
506 break;
507 case R_X86_64_64:
508 *(u64 *)location = value;
509 break;
510 case R_X86_64_32:
511 *(u32 *)location = value;
512 if (value != *(u32 *)location)
513 goto overflow;
514 break;
515 case R_X86_64_32S:
516 *(s32 *)location = value;
517 if ((s64)value != *(s32 *)location)
518 goto overflow;
519 break;
520 case R_X86_64_PC32:
521 case R_X86_64_PLT32:
522 value -= (u64)address;
523 *(u32 *)location = value;
524 break;
525 default:
526 pr_err("Unknown rela relocation: %llu\n",
527 ELF64_R_TYPE(rel[i].r_info));
528 return -ENOEXEC;
529 }
530 }
531 return 0;
532
533overflow:
534 pr_err("Overflow in relocation type %d value 0x%lx\n",
535 (int)ELF64_R_TYPE(rel[i].r_info), value);
536 return -ENOEXEC;
537}
538
539int arch_kimage_file_post_load_cleanup(struct kimage *image)
540{
541 vfree(image->elf_headers);
542 image->elf_headers = NULL;
543 image->elf_headers_sz = 0;
544
545 return kexec_image_post_load_cleanup_default(image);
546}
547#endif /* CONFIG_KEXEC_FILE */
548
549#ifdef CONFIG_CRASH_DUMP
550
551static int
552kexec_mark_range(unsigned long start, unsigned long end, bool protect)
553{
554 struct page *page;
555 unsigned int nr_pages;
556
557 /*
558 * For physical range: [start, end]. We must skip the unassigned
559 * crashk resource with zero-valued "end" member.
560 */
561 if (!end || start > end)
562 return 0;
563
564 page = pfn_to_page(start >> PAGE_SHIFT);
565 nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
566 if (protect)
567 return set_pages_ro(page, nr_pages);
568 else
569 return set_pages_rw(page, nr_pages);
570}
571
572static void kexec_mark_crashkres(bool protect)
573{
574 unsigned long control;
575
576 kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
577
578 /* Don't touch the control code page used in crash_kexec().*/
579 control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
580 kexec_mark_range(crashk_res.start, control - 1, protect);
581 control += KEXEC_CONTROL_PAGE_SIZE;
582 kexec_mark_range(control, crashk_res.end, protect);
583}
584
585void arch_kexec_protect_crashkres(void)
586{
587 kexec_mark_crashkres(true);
588}
589
590void arch_kexec_unprotect_crashkres(void)
591{
592 kexec_mark_crashkres(false);
593}
594#endif
595
596/*
597 * During a traditional boot under SME, SME will encrypt the kernel,
598 * so the SME kexec kernel also needs to be un-encrypted in order to
599 * replicate a normal SME boot.
600 *
601 * During a traditional boot under SEV, the kernel has already been
602 * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
603 * order to replicate a normal SEV boot.
604 */
605int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
606{
607 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
608 return 0;
609
610 /*
611 * If host memory encryption is active we need to be sure that kexec
612 * pages are not encrypted because when we boot to the new kernel the
613 * pages won't be accessed encrypted (initially).
614 */
615 return set_memory_decrypted((unsigned long)vaddr, pages);
616}
617
618void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
619{
620 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
621 return;
622
623 /*
624 * If host memory encryption is active we need to reset the pages back
625 * to being an encrypted mapping before freeing them.
626 */
627 set_memory_encrypted((unsigned long)vaddr, pages);
628}
1/*
2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
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#include <linux/vmalloc.h>
21
22#include <asm/init.h>
23#include <asm/pgtable.h>
24#include <asm/tlbflush.h>
25#include <asm/mmu_context.h>
26#include <asm/io_apic.h>
27#include <asm/debugreg.h>
28#include <asm/kexec-bzimage64.h>
29#include <asm/setup.h>
30
31#ifdef CONFIG_KEXEC_FILE
32static struct kexec_file_ops *kexec_file_loaders[] = {
33 &kexec_bzImage64_ops,
34};
35#endif
36
37static void free_transition_pgtable(struct kimage *image)
38{
39 free_page((unsigned long)image->arch.pud);
40 free_page((unsigned long)image->arch.pmd);
41 free_page((unsigned long)image->arch.pte);
42}
43
44static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
45{
46 pud_t *pud;
47 pmd_t *pmd;
48 pte_t *pte;
49 unsigned long vaddr, paddr;
50 int result = -ENOMEM;
51
52 vaddr = (unsigned long)relocate_kernel;
53 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
54 pgd += pgd_index(vaddr);
55 if (!pgd_present(*pgd)) {
56 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
57 if (!pud)
58 goto err;
59 image->arch.pud = pud;
60 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
61 }
62 pud = pud_offset(pgd, vaddr);
63 if (!pud_present(*pud)) {
64 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
65 if (!pmd)
66 goto err;
67 image->arch.pmd = pmd;
68 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
69 }
70 pmd = pmd_offset(pud, vaddr);
71 if (!pmd_present(*pmd)) {
72 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
73 if (!pte)
74 goto err;
75 image->arch.pte = pte;
76 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
77 }
78 pte = pte_offset_kernel(pmd, vaddr);
79 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
80 return 0;
81err:
82 free_transition_pgtable(image);
83 return result;
84}
85
86static void *alloc_pgt_page(void *data)
87{
88 struct kimage *image = (struct kimage *)data;
89 struct page *page;
90 void *p = NULL;
91
92 page = kimage_alloc_control_pages(image, 0);
93 if (page) {
94 p = page_address(page);
95 clear_page(p);
96 }
97
98 return p;
99}
100
101static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
102{
103 struct x86_mapping_info info = {
104 .alloc_pgt_page = alloc_pgt_page,
105 .context = image,
106 .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
107 };
108 unsigned long mstart, mend;
109 pgd_t *level4p;
110 int result;
111 int i;
112
113 level4p = (pgd_t *)__va(start_pgtable);
114 clear_page(level4p);
115 for (i = 0; i < nr_pfn_mapped; i++) {
116 mstart = pfn_mapped[i].start << PAGE_SHIFT;
117 mend = pfn_mapped[i].end << PAGE_SHIFT;
118
119 result = kernel_ident_mapping_init(&info,
120 level4p, mstart, mend);
121 if (result)
122 return result;
123 }
124
125 /*
126 * segments's mem ranges could be outside 0 ~ max_pfn,
127 * for example when jump back to original kernel from kexeced kernel.
128 * or first kernel is booted with user mem map, and second kernel
129 * could be loaded out of that range.
130 */
131 for (i = 0; i < image->nr_segments; i++) {
132 mstart = image->segment[i].mem;
133 mend = mstart + image->segment[i].memsz;
134
135 result = kernel_ident_mapping_init(&info,
136 level4p, mstart, mend);
137
138 if (result)
139 return result;
140 }
141
142 return init_transition_pgtable(image, level4p);
143}
144
145static void set_idt(void *newidt, u16 limit)
146{
147 struct desc_ptr curidt;
148
149 /* x86-64 supports unaliged loads & stores */
150 curidt.size = limit;
151 curidt.address = (unsigned long)newidt;
152
153 __asm__ __volatile__ (
154 "lidtq %0\n"
155 : : "m" (curidt)
156 );
157};
158
159
160static void set_gdt(void *newgdt, u16 limit)
161{
162 struct desc_ptr curgdt;
163
164 /* x86-64 supports unaligned loads & stores */
165 curgdt.size = limit;
166 curgdt.address = (unsigned long)newgdt;
167
168 __asm__ __volatile__ (
169 "lgdtq %0\n"
170 : : "m" (curgdt)
171 );
172};
173
174static void load_segments(void)
175{
176 __asm__ __volatile__ (
177 "\tmovl %0,%%ds\n"
178 "\tmovl %0,%%es\n"
179 "\tmovl %0,%%ss\n"
180 "\tmovl %0,%%fs\n"
181 "\tmovl %0,%%gs\n"
182 : : "a" (__KERNEL_DS) : "memory"
183 );
184}
185
186#ifdef CONFIG_KEXEC_FILE
187/* Update purgatory as needed after various image segments have been prepared */
188static int arch_update_purgatory(struct kimage *image)
189{
190 int ret = 0;
191
192 if (!image->file_mode)
193 return 0;
194
195 /* Setup copying of backup region */
196 if (image->type == KEXEC_TYPE_CRASH) {
197 ret = kexec_purgatory_get_set_symbol(image, "backup_dest",
198 &image->arch.backup_load_addr,
199 sizeof(image->arch.backup_load_addr), 0);
200 if (ret)
201 return ret;
202
203 ret = kexec_purgatory_get_set_symbol(image, "backup_src",
204 &image->arch.backup_src_start,
205 sizeof(image->arch.backup_src_start), 0);
206 if (ret)
207 return ret;
208
209 ret = kexec_purgatory_get_set_symbol(image, "backup_sz",
210 &image->arch.backup_src_sz,
211 sizeof(image->arch.backup_src_sz), 0);
212 if (ret)
213 return ret;
214 }
215
216 return ret;
217}
218#else /* !CONFIG_KEXEC_FILE */
219static inline int arch_update_purgatory(struct kimage *image)
220{
221 return 0;
222}
223#endif /* CONFIG_KEXEC_FILE */
224
225int machine_kexec_prepare(struct kimage *image)
226{
227 unsigned long start_pgtable;
228 int result;
229
230 /* Calculate the offsets */
231 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
232
233 /* Setup the identity mapped 64bit page table */
234 result = init_pgtable(image, start_pgtable);
235 if (result)
236 return result;
237
238 /* update purgatory as needed */
239 result = arch_update_purgatory(image);
240 if (result)
241 return result;
242
243 return 0;
244}
245
246void machine_kexec_cleanup(struct kimage *image)
247{
248 free_transition_pgtable(image);
249}
250
251/*
252 * Do not allocate memory (or fail in any way) in machine_kexec().
253 * We are past the point of no return, committed to rebooting now.
254 */
255void machine_kexec(struct kimage *image)
256{
257 unsigned long page_list[PAGES_NR];
258 void *control_page;
259 int save_ftrace_enabled;
260
261#ifdef CONFIG_KEXEC_JUMP
262 if (image->preserve_context)
263 save_processor_state();
264#endif
265
266 save_ftrace_enabled = __ftrace_enabled_save();
267
268 /* Interrupts aren't acceptable while we reboot */
269 local_irq_disable();
270 hw_breakpoint_disable();
271
272 if (image->preserve_context) {
273#ifdef CONFIG_X86_IO_APIC
274 /*
275 * We need to put APICs in legacy mode so that we can
276 * get timer interrupts in second kernel. kexec/kdump
277 * paths already have calls to disable_IO_APIC() in
278 * one form or other. kexec jump path also need
279 * one.
280 */
281 disable_IO_APIC();
282#endif
283 }
284
285 control_page = page_address(image->control_code_page) + PAGE_SIZE;
286 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
287
288 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
289 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
290 page_list[PA_TABLE_PAGE] =
291 (unsigned long)__pa(page_address(image->control_code_page));
292
293 if (image->type == KEXEC_TYPE_DEFAULT)
294 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
295 << PAGE_SHIFT);
296
297 /*
298 * The segment registers are funny things, they have both a
299 * visible and an invisible part. Whenever the visible part is
300 * set to a specific selector, the invisible part is loaded
301 * with from a table in memory. At no other time is the
302 * descriptor table in memory accessed.
303 *
304 * I take advantage of this here by force loading the
305 * segments, before I zap the gdt with an invalid value.
306 */
307 load_segments();
308 /*
309 * The gdt & idt are now invalid.
310 * If you want to load them you must set up your own idt & gdt.
311 */
312 set_gdt(phys_to_virt(0), 0);
313 set_idt(phys_to_virt(0), 0);
314
315 /* now call it */
316 image->start = relocate_kernel((unsigned long)image->head,
317 (unsigned long)page_list,
318 image->start,
319 image->preserve_context);
320
321#ifdef CONFIG_KEXEC_JUMP
322 if (image->preserve_context)
323 restore_processor_state();
324#endif
325
326 __ftrace_enabled_restore(save_ftrace_enabled);
327}
328
329void arch_crash_save_vmcoreinfo(void)
330{
331 VMCOREINFO_NUMBER(phys_base);
332 VMCOREINFO_SYMBOL(init_level4_pgt);
333
334#ifdef CONFIG_NUMA
335 VMCOREINFO_SYMBOL(node_data);
336 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
337#endif
338 vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
339 kaslr_offset());
340 VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
341}
342
343/* arch-dependent functionality related to kexec file-based syscall */
344
345#ifdef CONFIG_KEXEC_FILE
346int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
347 unsigned long buf_len)
348{
349 int i, ret = -ENOEXEC;
350 struct kexec_file_ops *fops;
351
352 for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
353 fops = kexec_file_loaders[i];
354 if (!fops || !fops->probe)
355 continue;
356
357 ret = fops->probe(buf, buf_len);
358 if (!ret) {
359 image->fops = fops;
360 return ret;
361 }
362 }
363
364 return ret;
365}
366
367void *arch_kexec_kernel_image_load(struct kimage *image)
368{
369 vfree(image->arch.elf_headers);
370 image->arch.elf_headers = NULL;
371
372 if (!image->fops || !image->fops->load)
373 return ERR_PTR(-ENOEXEC);
374
375 return image->fops->load(image, image->kernel_buf,
376 image->kernel_buf_len, image->initrd_buf,
377 image->initrd_buf_len, image->cmdline_buf,
378 image->cmdline_buf_len);
379}
380
381int arch_kimage_file_post_load_cleanup(struct kimage *image)
382{
383 if (!image->fops || !image->fops->cleanup)
384 return 0;
385
386 return image->fops->cleanup(image->image_loader_data);
387}
388
389#ifdef CONFIG_KEXEC_VERIFY_SIG
390int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
391 unsigned long kernel_len)
392{
393 if (!image->fops || !image->fops->verify_sig) {
394 pr_debug("kernel loader does not support signature verification.");
395 return -EKEYREJECTED;
396 }
397
398 return image->fops->verify_sig(kernel, kernel_len);
399}
400#endif
401
402/*
403 * Apply purgatory relocations.
404 *
405 * ehdr: Pointer to elf headers
406 * sechdrs: Pointer to section headers.
407 * relsec: section index of SHT_RELA section.
408 *
409 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
410 */
411int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
412 Elf64_Shdr *sechdrs, unsigned int relsec)
413{
414 unsigned int i;
415 Elf64_Rela *rel;
416 Elf64_Sym *sym;
417 void *location;
418 Elf64_Shdr *section, *symtabsec;
419 unsigned long address, sec_base, value;
420 const char *strtab, *name, *shstrtab;
421
422 /*
423 * ->sh_offset has been modified to keep the pointer to section
424 * contents in memory
425 */
426 rel = (void *)sechdrs[relsec].sh_offset;
427
428 /* Section to which relocations apply */
429 section = &sechdrs[sechdrs[relsec].sh_info];
430
431 pr_debug("Applying relocate section %u to %u\n", relsec,
432 sechdrs[relsec].sh_info);
433
434 /* Associated symbol table */
435 symtabsec = &sechdrs[sechdrs[relsec].sh_link];
436
437 /* String table */
438 if (symtabsec->sh_link >= ehdr->e_shnum) {
439 /* Invalid strtab section number */
440 pr_err("Invalid string table section index %d\n",
441 symtabsec->sh_link);
442 return -ENOEXEC;
443 }
444
445 strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;
446
447 /* section header string table */
448 shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;
449
450 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
451
452 /*
453 * rel[i].r_offset contains byte offset from beginning
454 * of section to the storage unit affected.
455 *
456 * This is location to update (->sh_offset). This is temporary
457 * buffer where section is currently loaded. This will finally
458 * be loaded to a different address later, pointed to by
459 * ->sh_addr. kexec takes care of moving it
460 * (kexec_load_segment()).
461 */
462 location = (void *)(section->sh_offset + rel[i].r_offset);
463
464 /* Final address of the location */
465 address = section->sh_addr + rel[i].r_offset;
466
467 /*
468 * rel[i].r_info contains information about symbol table index
469 * w.r.t which relocation must be made and type of relocation
470 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
471 * these respectively.
472 */
473 sym = (Elf64_Sym *)symtabsec->sh_offset +
474 ELF64_R_SYM(rel[i].r_info);
475
476 if (sym->st_name)
477 name = strtab + sym->st_name;
478 else
479 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
480
481 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
482 name, sym->st_info, sym->st_shndx, sym->st_value,
483 sym->st_size);
484
485 if (sym->st_shndx == SHN_UNDEF) {
486 pr_err("Undefined symbol: %s\n", name);
487 return -ENOEXEC;
488 }
489
490 if (sym->st_shndx == SHN_COMMON) {
491 pr_err("symbol '%s' in common section\n", name);
492 return -ENOEXEC;
493 }
494
495 if (sym->st_shndx == SHN_ABS)
496 sec_base = 0;
497 else if (sym->st_shndx >= ehdr->e_shnum) {
498 pr_err("Invalid section %d for symbol %s\n",
499 sym->st_shndx, name);
500 return -ENOEXEC;
501 } else
502 sec_base = sechdrs[sym->st_shndx].sh_addr;
503
504 value = sym->st_value;
505 value += sec_base;
506 value += rel[i].r_addend;
507
508 switch (ELF64_R_TYPE(rel[i].r_info)) {
509 case R_X86_64_NONE:
510 break;
511 case R_X86_64_64:
512 *(u64 *)location = value;
513 break;
514 case R_X86_64_32:
515 *(u32 *)location = value;
516 if (value != *(u32 *)location)
517 goto overflow;
518 break;
519 case R_X86_64_32S:
520 *(s32 *)location = value;
521 if ((s64)value != *(s32 *)location)
522 goto overflow;
523 break;
524 case R_X86_64_PC32:
525 value -= (u64)address;
526 *(u32 *)location = value;
527 break;
528 default:
529 pr_err("Unknown rela relocation: %llu\n",
530 ELF64_R_TYPE(rel[i].r_info));
531 return -ENOEXEC;
532 }
533 }
534 return 0;
535
536overflow:
537 pr_err("Overflow in relocation type %d value 0x%lx\n",
538 (int)ELF64_R_TYPE(rel[i].r_info), value);
539 return -ENOEXEC;
540}
541#endif /* CONFIG_KEXEC_FILE */
542
543static int
544kexec_mark_range(unsigned long start, unsigned long end, bool protect)
545{
546 struct page *page;
547 unsigned int nr_pages;
548
549 /*
550 * For physical range: [start, end]. We must skip the unassigned
551 * crashk resource with zero-valued "end" member.
552 */
553 if (!end || start > end)
554 return 0;
555
556 page = pfn_to_page(start >> PAGE_SHIFT);
557 nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
558 if (protect)
559 return set_pages_ro(page, nr_pages);
560 else
561 return set_pages_rw(page, nr_pages);
562}
563
564static void kexec_mark_crashkres(bool protect)
565{
566 unsigned long control;
567
568 kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
569
570 /* Don't touch the control code page used in crash_kexec().*/
571 control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
572 /* Control code page is located in the 2nd page. */
573 kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
574 control += KEXEC_CONTROL_PAGE_SIZE;
575 kexec_mark_range(control, crashk_res.end, protect);
576}
577
578void arch_kexec_protect_crashkres(void)
579{
580 kexec_mark_crashkres(true);
581}
582
583void arch_kexec_unprotect_crashkres(void)
584{
585 kexec_mark_crashkres(false);
586}