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