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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
32#ifdef CONFIG_ACPI
33/*
34 * Used while adding mapping for ACPI tables.
35 * Can be reused when other iomem regions need be mapped
36 */
37struct init_pgtable_data {
38 struct x86_mapping_info *info;
39 pgd_t *level4p;
40};
41
42static int mem_region_callback(struct resource *res, void *arg)
43{
44 struct init_pgtable_data *data = arg;
45 unsigned long mstart, mend;
46
47 mstart = res->start;
48 mend = mstart + resource_size(res) - 1;
49
50 return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
51}
52
53static int
54map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p)
55{
56 struct init_pgtable_data data;
57 unsigned long flags;
58 int ret;
59
60 data.info = info;
61 data.level4p = level4p;
62 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
63
64 ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
65 &data, mem_region_callback);
66 if (ret && ret != -EINVAL)
67 return ret;
68
69 /* ACPI tables could be located in ACPI Non-volatile Storage region */
70 ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
71 &data, mem_region_callback);
72 if (ret && ret != -EINVAL)
73 return ret;
74
75 return 0;
76}
77#else
78static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; }
79#endif
80
81#ifdef CONFIG_KEXEC_FILE
82const struct kexec_file_ops * const kexec_file_loaders[] = {
83 &kexec_bzImage64_ops,
84 NULL
85};
86#endif
87
88static int
89map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p)
90{
91#ifdef CONFIG_EFI
92 unsigned long mstart, mend;
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 return kernel_ident_mapping_init(info, level4p, mstart, mend);
109#endif
110 return 0;
111}
112
113static void free_transition_pgtable(struct kimage *image)
114{
115 free_page((unsigned long)image->arch.p4d);
116 image->arch.p4d = NULL;
117 free_page((unsigned long)image->arch.pud);
118 image->arch.pud = NULL;
119 free_page((unsigned long)image->arch.pmd);
120 image->arch.pmd = NULL;
121 free_page((unsigned long)image->arch.pte);
122 image->arch.pte = NULL;
123}
124
125static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
126{
127 pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
128 unsigned long vaddr, paddr;
129 int result = -ENOMEM;
130 p4d_t *p4d;
131 pud_t *pud;
132 pmd_t *pmd;
133 pte_t *pte;
134
135 vaddr = (unsigned long)relocate_kernel;
136 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
137 pgd += pgd_index(vaddr);
138 if (!pgd_present(*pgd)) {
139 p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
140 if (!p4d)
141 goto err;
142 image->arch.p4d = p4d;
143 set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));
144 }
145 p4d = p4d_offset(pgd, vaddr);
146 if (!p4d_present(*p4d)) {
147 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
148 if (!pud)
149 goto err;
150 image->arch.pud = pud;
151 set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
152 }
153 pud = pud_offset(p4d, vaddr);
154 if (!pud_present(*pud)) {
155 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
156 if (!pmd)
157 goto err;
158 image->arch.pmd = pmd;
159 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
160 }
161 pmd = pmd_offset(pud, vaddr);
162 if (!pmd_present(*pmd)) {
163 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
164 if (!pte)
165 goto err;
166 image->arch.pte = pte;
167 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
168 }
169 pte = pte_offset_kernel(pmd, vaddr);
170
171 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
172 prot = PAGE_KERNEL_EXEC;
173
174 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
175 return 0;
176err:
177 return result;
178}
179
180static void *alloc_pgt_page(void *data)
181{
182 struct kimage *image = (struct kimage *)data;
183 struct page *page;
184 void *p = NULL;
185
186 page = kimage_alloc_control_pages(image, 0);
187 if (page) {
188 p = page_address(page);
189 clear_page(p);
190 }
191
192 return p;
193}
194
195static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
196{
197 struct x86_mapping_info info = {
198 .alloc_pgt_page = alloc_pgt_page,
199 .context = image,
200 .page_flag = __PAGE_KERNEL_LARGE_EXEC,
201 .kernpg_flag = _KERNPG_TABLE_NOENC,
202 };
203 unsigned long mstart, mend;
204 pgd_t *level4p;
205 int result;
206 int i;
207
208 level4p = (pgd_t *)__va(start_pgtable);
209 clear_page(level4p);
210
211 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
212 info.page_flag |= _PAGE_ENC;
213 info.kernpg_flag |= _PAGE_ENC;
214 }
215
216 if (direct_gbpages)
217 info.direct_gbpages = true;
218
219 for (i = 0; i < nr_pfn_mapped; i++) {
220 mstart = pfn_mapped[i].start << PAGE_SHIFT;
221 mend = pfn_mapped[i].end << PAGE_SHIFT;
222
223 result = kernel_ident_mapping_init(&info,
224 level4p, mstart, mend);
225 if (result)
226 return result;
227 }
228
229 /*
230 * segments's mem ranges could be outside 0 ~ max_pfn,
231 * for example when jump back to original kernel from kexeced kernel.
232 * or first kernel is booted with user mem map, and second kernel
233 * could be loaded out of that range.
234 */
235 for (i = 0; i < image->nr_segments; i++) {
236 mstart = image->segment[i].mem;
237 mend = mstart + image->segment[i].memsz;
238
239 result = kernel_ident_mapping_init(&info,
240 level4p, mstart, mend);
241
242 if (result)
243 return result;
244 }
245
246 /*
247 * Prepare EFI systab and ACPI tables for kexec kernel since they are
248 * not covered by pfn_mapped.
249 */
250 result = map_efi_systab(&info, level4p);
251 if (result)
252 return result;
253
254 result = map_acpi_tables(&info, level4p);
255 if (result)
256 return result;
257
258 return init_transition_pgtable(image, level4p);
259}
260
261static void load_segments(void)
262{
263 __asm__ __volatile__ (
264 "\tmovl %0,%%ds\n"
265 "\tmovl %0,%%es\n"
266 "\tmovl %0,%%ss\n"
267 "\tmovl %0,%%fs\n"
268 "\tmovl %0,%%gs\n"
269 : : "a" (__KERNEL_DS) : "memory"
270 );
271}
272
273int machine_kexec_prepare(struct kimage *image)
274{
275 unsigned long start_pgtable;
276 int result;
277
278 /* Calculate the offsets */
279 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
280
281 /* Setup the identity mapped 64bit page table */
282 result = init_pgtable(image, start_pgtable);
283 if (result)
284 return result;
285
286 return 0;
287}
288
289void machine_kexec_cleanup(struct kimage *image)
290{
291 free_transition_pgtable(image);
292}
293
294/*
295 * Do not allocate memory (or fail in any way) in machine_kexec().
296 * We are past the point of no return, committed to rebooting now.
297 */
298void machine_kexec(struct kimage *image)
299{
300 unsigned long page_list[PAGES_NR];
301 void *control_page;
302 int save_ftrace_enabled;
303
304#ifdef CONFIG_KEXEC_JUMP
305 if (image->preserve_context)
306 save_processor_state();
307#endif
308
309 save_ftrace_enabled = __ftrace_enabled_save();
310
311 /* Interrupts aren't acceptable while we reboot */
312 local_irq_disable();
313 hw_breakpoint_disable();
314 cet_disable();
315
316 if (image->preserve_context) {
317#ifdef CONFIG_X86_IO_APIC
318 /*
319 * We need to put APICs in legacy mode so that we can
320 * get timer interrupts in second kernel. kexec/kdump
321 * paths already have calls to restore_boot_irq_mode()
322 * in one form or other. kexec jump path also need one.
323 */
324 clear_IO_APIC();
325 restore_boot_irq_mode();
326#endif
327 }
328
329 control_page = page_address(image->control_code_page) + PAGE_SIZE;
330 __memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
331
332 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
333 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
334 page_list[PA_TABLE_PAGE] =
335 (unsigned long)__pa(page_address(image->control_code_page));
336
337 if (image->type == KEXEC_TYPE_DEFAULT)
338 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
339 << PAGE_SHIFT);
340
341 /*
342 * The segment registers are funny things, they have both a
343 * visible and an invisible part. Whenever the visible part is
344 * set to a specific selector, the invisible part is loaded
345 * with from a table in memory. At no other time is the
346 * descriptor table in memory accessed.
347 *
348 * I take advantage of this here by force loading the
349 * segments, before I zap the gdt with an invalid value.
350 */
351 load_segments();
352 /*
353 * The gdt & idt are now invalid.
354 * If you want to load them you must set up your own idt & gdt.
355 */
356 native_idt_invalidate();
357 native_gdt_invalidate();
358
359 /* now call it */
360 image->start = relocate_kernel((unsigned long)image->head,
361 (unsigned long)page_list,
362 image->start,
363 image->preserve_context,
364 cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT));
365
366#ifdef CONFIG_KEXEC_JUMP
367 if (image->preserve_context)
368 restore_processor_state();
369#endif
370
371 __ftrace_enabled_restore(save_ftrace_enabled);
372}
373
374/* arch-dependent functionality related to kexec file-based syscall */
375
376#ifdef CONFIG_KEXEC_FILE
377void *arch_kexec_kernel_image_load(struct kimage *image)
378{
379 if (!image->fops || !image->fops->load)
380 return ERR_PTR(-ENOEXEC);
381
382 return image->fops->load(image, image->kernel_buf,
383 image->kernel_buf_len, image->initrd_buf,
384 image->initrd_buf_len, image->cmdline_buf,
385 image->cmdline_buf_len);
386}
387
388/*
389 * Apply purgatory relocations.
390 *
391 * @pi: Purgatory to be relocated.
392 * @section: Section relocations applying to.
393 * @relsec: Section containing RELAs.
394 * @symtabsec: Corresponding symtab.
395 *
396 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
397 */
398int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
399 Elf_Shdr *section, const Elf_Shdr *relsec,
400 const Elf_Shdr *symtabsec)
401{
402 unsigned int i;
403 Elf64_Rela *rel;
404 Elf64_Sym *sym;
405 void *location;
406 unsigned long address, sec_base, value;
407 const char *strtab, *name, *shstrtab;
408 const Elf_Shdr *sechdrs;
409
410 /* String & section header string table */
411 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
412 strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
413 shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
414
415 rel = (void *)pi->ehdr + relsec->sh_offset;
416
417 pr_debug("Applying relocate section %s to %u\n",
418 shstrtab + relsec->sh_name, relsec->sh_info);
419
420 for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {
421
422 /*
423 * rel[i].r_offset contains byte offset from beginning
424 * of section to the storage unit affected.
425 *
426 * This is location to update. This is temporary buffer
427 * where section is currently loaded. This will finally be
428 * loaded to a different address later, pointed to by
429 * ->sh_addr. kexec takes care of moving it
430 * (kexec_load_segment()).
431 */
432 location = pi->purgatory_buf;
433 location += section->sh_offset;
434 location += rel[i].r_offset;
435
436 /* Final address of the location */
437 address = section->sh_addr + rel[i].r_offset;
438
439 /*
440 * rel[i].r_info contains information about symbol table index
441 * w.r.t which relocation must be made and type of relocation
442 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
443 * these respectively.
444 */
445 sym = (void *)pi->ehdr + symtabsec->sh_offset;
446 sym += ELF64_R_SYM(rel[i].r_info);
447
448 if (sym->st_name)
449 name = strtab + sym->st_name;
450 else
451 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
452
453 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
454 name, sym->st_info, sym->st_shndx, sym->st_value,
455 sym->st_size);
456
457 if (sym->st_shndx == SHN_UNDEF) {
458 pr_err("Undefined symbol: %s\n", name);
459 return -ENOEXEC;
460 }
461
462 if (sym->st_shndx == SHN_COMMON) {
463 pr_err("symbol '%s' in common section\n", name);
464 return -ENOEXEC;
465 }
466
467 if (sym->st_shndx == SHN_ABS)
468 sec_base = 0;
469 else if (sym->st_shndx >= pi->ehdr->e_shnum) {
470 pr_err("Invalid section %d for symbol %s\n",
471 sym->st_shndx, name);
472 return -ENOEXEC;
473 } else
474 sec_base = pi->sechdrs[sym->st_shndx].sh_addr;
475
476 value = sym->st_value;
477 value += sec_base;
478 value += rel[i].r_addend;
479
480 switch (ELF64_R_TYPE(rel[i].r_info)) {
481 case R_X86_64_NONE:
482 break;
483 case R_X86_64_64:
484 *(u64 *)location = value;
485 break;
486 case R_X86_64_32:
487 *(u32 *)location = value;
488 if (value != *(u32 *)location)
489 goto overflow;
490 break;
491 case R_X86_64_32S:
492 *(s32 *)location = value;
493 if ((s64)value != *(s32 *)location)
494 goto overflow;
495 break;
496 case R_X86_64_PC32:
497 case R_X86_64_PLT32:
498 value -= (u64)address;
499 *(u32 *)location = value;
500 break;
501 default:
502 pr_err("Unknown rela relocation: %llu\n",
503 ELF64_R_TYPE(rel[i].r_info));
504 return -ENOEXEC;
505 }
506 }
507 return 0;
508
509overflow:
510 pr_err("Overflow in relocation type %d value 0x%lx\n",
511 (int)ELF64_R_TYPE(rel[i].r_info), value);
512 return -ENOEXEC;
513}
514
515int arch_kimage_file_post_load_cleanup(struct kimage *image)
516{
517 vfree(image->elf_headers);
518 image->elf_headers = NULL;
519 image->elf_headers_sz = 0;
520
521 return kexec_image_post_load_cleanup_default(image);
522}
523#endif /* CONFIG_KEXEC_FILE */
524
525static int
526kexec_mark_range(unsigned long start, unsigned long end, bool protect)
527{
528 struct page *page;
529 unsigned int nr_pages;
530
531 /*
532 * For physical range: [start, end]. We must skip the unassigned
533 * crashk resource with zero-valued "end" member.
534 */
535 if (!end || start > end)
536 return 0;
537
538 page = pfn_to_page(start >> PAGE_SHIFT);
539 nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
540 if (protect)
541 return set_pages_ro(page, nr_pages);
542 else
543 return set_pages_rw(page, nr_pages);
544}
545
546static void kexec_mark_crashkres(bool protect)
547{
548 unsigned long control;
549
550 kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
551
552 /* Don't touch the control code page used in crash_kexec().*/
553 control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
554 /* Control code page is located in the 2nd page. */
555 kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
556 control += KEXEC_CONTROL_PAGE_SIZE;
557 kexec_mark_range(control, crashk_res.end, protect);
558}
559
560void arch_kexec_protect_crashkres(void)
561{
562 kexec_mark_crashkres(true);
563}
564
565void arch_kexec_unprotect_crashkres(void)
566{
567 kexec_mark_crashkres(false);
568}
569
570/*
571 * During a traditional boot under SME, SME will encrypt the kernel,
572 * so the SME kexec kernel also needs to be un-encrypted in order to
573 * replicate a normal SME boot.
574 *
575 * During a traditional boot under SEV, the kernel has already been
576 * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
577 * order to replicate a normal SEV boot.
578 */
579int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
580{
581 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
582 return 0;
583
584 /*
585 * If host memory encryption is active we need to be sure that kexec
586 * pages are not encrypted because when we boot to the new kernel the
587 * pages won't be accessed encrypted (initially).
588 */
589 return set_memory_decrypted((unsigned long)vaddr, pages);
590}
591
592void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
593{
594 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
595 return;
596
597 /*
598 * If host memory encryption is active we need to reset the pages back
599 * to being an encrypted mapping before freeing them.
600 */
601 set_memory_encrypted((unsigned long)vaddr, pages);
602}
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#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
19#include <asm/pgtable.h>
20#include <asm/tlbflush.h>
21#include <asm/mmu_context.h>
22#include <asm/debugreg.h>
23
24static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
25 unsigned long addr)
26{
27 pud_t *pud;
28 pmd_t *pmd;
29 struct page *page;
30 int result = -ENOMEM;
31
32 addr &= PMD_MASK;
33 pgd += pgd_index(addr);
34 if (!pgd_present(*pgd)) {
35 page = kimage_alloc_control_pages(image, 0);
36 if (!page)
37 goto out;
38 pud = (pud_t *)page_address(page);
39 clear_page(pud);
40 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
41 }
42 pud = pud_offset(pgd, addr);
43 if (!pud_present(*pud)) {
44 page = kimage_alloc_control_pages(image, 0);
45 if (!page)
46 goto out;
47 pmd = (pmd_t *)page_address(page);
48 clear_page(pmd);
49 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
50 }
51 pmd = pmd_offset(pud, addr);
52 if (!pmd_present(*pmd))
53 set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
54 result = 0;
55out:
56 return result;
57}
58
59static void init_level2_page(pmd_t *level2p, unsigned long addr)
60{
61 unsigned long end_addr;
62
63 addr &= PAGE_MASK;
64 end_addr = addr + PUD_SIZE;
65 while (addr < end_addr) {
66 set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
67 addr += PMD_SIZE;
68 }
69}
70
71static int init_level3_page(struct kimage *image, pud_t *level3p,
72 unsigned long addr, unsigned long last_addr)
73{
74 unsigned long end_addr;
75 int result;
76
77 result = 0;
78 addr &= PAGE_MASK;
79 end_addr = addr + PGDIR_SIZE;
80 while ((addr < last_addr) && (addr < end_addr)) {
81 struct page *page;
82 pmd_t *level2p;
83
84 page = kimage_alloc_control_pages(image, 0);
85 if (!page) {
86 result = -ENOMEM;
87 goto out;
88 }
89 level2p = (pmd_t *)page_address(page);
90 init_level2_page(level2p, addr);
91 set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
92 addr += PUD_SIZE;
93 }
94 /* clear the unused entries */
95 while (addr < end_addr) {
96 pud_clear(level3p++);
97 addr += PUD_SIZE;
98 }
99out:
100 return result;
101}
102
103
104static int init_level4_page(struct kimage *image, pgd_t *level4p,
105 unsigned long addr, unsigned long last_addr)
106{
107 unsigned long end_addr;
108 int result;
109
110 result = 0;
111 addr &= PAGE_MASK;
112 end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
113 while ((addr < last_addr) && (addr < end_addr)) {
114 struct page *page;
115 pud_t *level3p;
116
117 page = kimage_alloc_control_pages(image, 0);
118 if (!page) {
119 result = -ENOMEM;
120 goto out;
121 }
122 level3p = (pud_t *)page_address(page);
123 result = init_level3_page(image, level3p, addr, last_addr);
124 if (result)
125 goto out;
126 set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
127 addr += PGDIR_SIZE;
128 }
129 /* clear the unused entries */
130 while (addr < end_addr) {
131 pgd_clear(level4p++);
132 addr += PGDIR_SIZE;
133 }
134out:
135 return result;
136}
137
138static void free_transition_pgtable(struct kimage *image)
139{
140 free_page((unsigned long)image->arch.pud);
141 free_page((unsigned long)image->arch.pmd);
142 free_page((unsigned long)image->arch.pte);
143}
144
145static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
146{
147 pud_t *pud;
148 pmd_t *pmd;
149 pte_t *pte;
150 unsigned long vaddr, paddr;
151 int result = -ENOMEM;
152
153 vaddr = (unsigned long)relocate_kernel;
154 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
155 pgd += pgd_index(vaddr);
156 if (!pgd_present(*pgd)) {
157 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
158 if (!pud)
159 goto err;
160 image->arch.pud = pud;
161 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
162 }
163 pud = pud_offset(pgd, vaddr);
164 if (!pud_present(*pud)) {
165 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
166 if (!pmd)
167 goto err;
168 image->arch.pmd = pmd;
169 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
170 }
171 pmd = pmd_offset(pud, vaddr);
172 if (!pmd_present(*pmd)) {
173 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
174 if (!pte)
175 goto err;
176 image->arch.pte = pte;
177 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
178 }
179 pte = pte_offset_kernel(pmd, vaddr);
180 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
181 return 0;
182err:
183 free_transition_pgtable(image);
184 return result;
185}
186
187
188static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
189{
190 pgd_t *level4p;
191 int result;
192 level4p = (pgd_t *)__va(start_pgtable);
193 result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
194 if (result)
195 return result;
196 /*
197 * image->start may be outside 0 ~ max_pfn, for example when
198 * jump back to original kernel from kexeced kernel
199 */
200 result = init_one_level2_page(image, level4p, image->start);
201 if (result)
202 return result;
203 return init_transition_pgtable(image, level4p);
204}
205
206static void set_idt(void *newidt, u16 limit)
207{
208 struct desc_ptr curidt;
209
210 /* x86-64 supports unaliged loads & stores */
211 curidt.size = limit;
212 curidt.address = (unsigned long)newidt;
213
214 __asm__ __volatile__ (
215 "lidtq %0\n"
216 : : "m" (curidt)
217 );
218};
219
220
221static void set_gdt(void *newgdt, u16 limit)
222{
223 struct desc_ptr curgdt;
224
225 /* x86-64 supports unaligned loads & stores */
226 curgdt.size = limit;
227 curgdt.address = (unsigned long)newgdt;
228
229 __asm__ __volatile__ (
230 "lgdtq %0\n"
231 : : "m" (curgdt)
232 );
233};
234
235static void load_segments(void)
236{
237 __asm__ __volatile__ (
238 "\tmovl %0,%%ds\n"
239 "\tmovl %0,%%es\n"
240 "\tmovl %0,%%ss\n"
241 "\tmovl %0,%%fs\n"
242 "\tmovl %0,%%gs\n"
243 : : "a" (__KERNEL_DS) : "memory"
244 );
245}
246
247int machine_kexec_prepare(struct kimage *image)
248{
249 unsigned long start_pgtable;
250 int result;
251
252 /* Calculate the offsets */
253 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
254
255 /* Setup the identity mapped 64bit page table */
256 result = init_pgtable(image, start_pgtable);
257 if (result)
258 return result;
259
260 return 0;
261}
262
263void machine_kexec_cleanup(struct kimage *image)
264{
265 free_transition_pgtable(image);
266}
267
268/*
269 * Do not allocate memory (or fail in any way) in machine_kexec().
270 * We are past the point of no return, committed to rebooting now.
271 */
272void machine_kexec(struct kimage *image)
273{
274 unsigned long page_list[PAGES_NR];
275 void *control_page;
276 int save_ftrace_enabled;
277
278#ifdef CONFIG_KEXEC_JUMP
279 if (image->preserve_context)
280 save_processor_state();
281#endif
282
283 save_ftrace_enabled = __ftrace_enabled_save();
284
285 /* Interrupts aren't acceptable while we reboot */
286 local_irq_disable();
287 hw_breakpoint_disable();
288
289 if (image->preserve_context) {
290#ifdef CONFIG_X86_IO_APIC
291 /*
292 * We need to put APICs in legacy mode so that we can
293 * get timer interrupts in second kernel. kexec/kdump
294 * paths already have calls to disable_IO_APIC() in
295 * one form or other. kexec jump path also need
296 * one.
297 */
298 disable_IO_APIC();
299#endif
300 }
301
302 control_page = page_address(image->control_code_page) + PAGE_SIZE;
303 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
304
305 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
306 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
307 page_list[PA_TABLE_PAGE] =
308 (unsigned long)__pa(page_address(image->control_code_page));
309
310 if (image->type == KEXEC_TYPE_DEFAULT)
311 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
312 << PAGE_SHIFT);
313
314 /*
315 * The segment registers are funny things, they have both a
316 * visible and an invisible part. Whenever the visible part is
317 * set to a specific selector, the invisible part is loaded
318 * with from a table in memory. At no other time is the
319 * descriptor table in memory accessed.
320 *
321 * I take advantage of this here by force loading the
322 * segments, before I zap the gdt with an invalid value.
323 */
324 load_segments();
325 /*
326 * The gdt & idt are now invalid.
327 * If you want to load them you must set up your own idt & gdt.
328 */
329 set_gdt(phys_to_virt(0), 0);
330 set_idt(phys_to_virt(0), 0);
331
332 /* now call it */
333 image->start = relocate_kernel((unsigned long)image->head,
334 (unsigned long)page_list,
335 image->start,
336 image->preserve_context);
337
338#ifdef CONFIG_KEXEC_JUMP
339 if (image->preserve_context)
340 restore_processor_state();
341#endif
342
343 __ftrace_enabled_restore(save_ftrace_enabled);
344}
345
346void arch_crash_save_vmcoreinfo(void)
347{
348 VMCOREINFO_SYMBOL(phys_base);
349 VMCOREINFO_SYMBOL(init_level4_pgt);
350
351#ifdef CONFIG_NUMA
352 VMCOREINFO_SYMBOL(node_data);
353 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
354#endif
355}
356