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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
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#include <asm/setup.h>
29#include <asm/set_memory.h>
30
31#ifdef CONFIG_ACPI
32/*
33 * Used while adding mapping for ACPI tables.
34 * Can be reused when other iomem regions need be mapped
35 */
36struct init_pgtable_data {
37 struct x86_mapping_info *info;
38 pgd_t *level4p;
39};
40
41static int mem_region_callback(struct resource *res, void *arg)
42{
43 struct init_pgtable_data *data = arg;
44 unsigned long mstart, mend;
45
46 mstart = res->start;
47 mend = mstart + resource_size(res) - 1;
48
49 return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
50}
51
52static int
53map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p)
54{
55 struct init_pgtable_data data;
56 unsigned long flags;
57 int ret;
58
59 data.info = info;
60 data.level4p = level4p;
61 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
62
63 ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
64 &data, mem_region_callback);
65 if (ret && ret != -EINVAL)
66 return ret;
67
68 /* ACPI tables could be located in ACPI Non-volatile Storage region */
69 ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
70 &data, mem_region_callback);
71 if (ret && ret != -EINVAL)
72 return ret;
73
74 return 0;
75}
76#else
77static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; }
78#endif
79
80#ifdef CONFIG_KEXEC_FILE
81const struct kexec_file_ops * const kexec_file_loaders[] = {
82 &kexec_bzImage64_ops,
83 NULL
84};
85#endif
86
87static int
88map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p)
89{
90#ifdef CONFIG_EFI
91 unsigned long mstart, mend;
92
93 if (!efi_enabled(EFI_BOOT))
94 return 0;
95
96 mstart = (boot_params.efi_info.efi_systab |
97 ((u64)boot_params.efi_info.efi_systab_hi<<32));
98
99 if (efi_enabled(EFI_64BIT))
100 mend = mstart + sizeof(efi_system_table_64_t);
101 else
102 mend = mstart + sizeof(efi_system_table_32_t);
103
104 if (!mstart)
105 return 0;
106
107 return kernel_ident_mapping_init(info, level4p, mstart, mend);
108#endif
109 return 0;
110}
111
112static void free_transition_pgtable(struct kimage *image)
113{
114 free_page((unsigned long)image->arch.p4d);
115 image->arch.p4d = NULL;
116 free_page((unsigned long)image->arch.pud);
117 image->arch.pud = NULL;
118 free_page((unsigned long)image->arch.pmd);
119 image->arch.pmd = NULL;
120 free_page((unsigned long)image->arch.pte);
121 image->arch.pte = NULL;
122}
123
124static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
125{
126 pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
127 unsigned long vaddr, paddr;
128 int result = -ENOMEM;
129 p4d_t *p4d;
130 pud_t *pud;
131 pmd_t *pmd;
132 pte_t *pte;
133
134 vaddr = (unsigned long)relocate_kernel;
135 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
136 pgd += pgd_index(vaddr);
137 if (!pgd_present(*pgd)) {
138 p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
139 if (!p4d)
140 goto err;
141 image->arch.p4d = p4d;
142 set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));
143 }
144 p4d = p4d_offset(pgd, vaddr);
145 if (!p4d_present(*p4d)) {
146 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
147 if (!pud)
148 goto err;
149 image->arch.pud = pud;
150 set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
151 }
152 pud = pud_offset(p4d, vaddr);
153 if (!pud_present(*pud)) {
154 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
155 if (!pmd)
156 goto err;
157 image->arch.pmd = pmd;
158 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
159 }
160 pmd = pmd_offset(pud, vaddr);
161 if (!pmd_present(*pmd)) {
162 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
163 if (!pte)
164 goto err;
165 image->arch.pte = pte;
166 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
167 }
168 pte = pte_offset_kernel(pmd, vaddr);
169
170 if (sev_active())
171 prot = PAGE_KERNEL_EXEC;
172
173 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
174 return 0;
175err:
176 return result;
177}
178
179static void *alloc_pgt_page(void *data)
180{
181 struct kimage *image = (struct kimage *)data;
182 struct page *page;
183 void *p = NULL;
184
185 page = kimage_alloc_control_pages(image, 0);
186 if (page) {
187 p = page_address(page);
188 clear_page(p);
189 }
190
191 return p;
192}
193
194static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
195{
196 struct x86_mapping_info info = {
197 .alloc_pgt_page = alloc_pgt_page,
198 .context = image,
199 .page_flag = __PAGE_KERNEL_LARGE_EXEC,
200 .kernpg_flag = _KERNPG_TABLE_NOENC,
201 };
202 unsigned long mstart, mend;
203 pgd_t *level4p;
204 int result;
205 int i;
206
207 level4p = (pgd_t *)__va(start_pgtable);
208 clear_page(level4p);
209
210 if (sev_active()) {
211 info.page_flag |= _PAGE_ENC;
212 info.kernpg_flag |= _PAGE_ENC;
213 }
214
215 if (direct_gbpages)
216 info.direct_gbpages = true;
217
218 for (i = 0; i < nr_pfn_mapped; i++) {
219 mstart = pfn_mapped[i].start << PAGE_SHIFT;
220 mend = pfn_mapped[i].end << PAGE_SHIFT;
221
222 result = kernel_ident_mapping_init(&info,
223 level4p, mstart, mend);
224 if (result)
225 return result;
226 }
227
228 /*
229 * segments's mem ranges could be outside 0 ~ max_pfn,
230 * for example when jump back to original kernel from kexeced kernel.
231 * or first kernel is booted with user mem map, and second kernel
232 * could be loaded out of that range.
233 */
234 for (i = 0; i < image->nr_segments; i++) {
235 mstart = image->segment[i].mem;
236 mend = mstart + image->segment[i].memsz;
237
238 result = kernel_ident_mapping_init(&info,
239 level4p, mstart, mend);
240
241 if (result)
242 return result;
243 }
244
245 /*
246 * Prepare EFI systab and ACPI tables for kexec kernel since they are
247 * not covered by pfn_mapped.
248 */
249 result = map_efi_systab(&info, level4p);
250 if (result)
251 return result;
252
253 result = map_acpi_tables(&info, level4p);
254 if (result)
255 return result;
256
257 return init_transition_pgtable(image, level4p);
258}
259
260static void set_idt(void *newidt, u16 limit)
261{
262 struct desc_ptr curidt;
263
264 /* x86-64 supports unaliged loads & stores */
265 curidt.size = limit;
266 curidt.address = (unsigned long)newidt;
267
268 __asm__ __volatile__ (
269 "lidtq %0\n"
270 : : "m" (curidt)
271 );
272};
273
274
275static void set_gdt(void *newgdt, u16 limit)
276{
277 struct desc_ptr curgdt;
278
279 /* x86-64 supports unaligned loads & stores */
280 curgdt.size = limit;
281 curgdt.address = (unsigned long)newgdt;
282
283 __asm__ __volatile__ (
284 "lgdtq %0\n"
285 : : "m" (curgdt)
286 );
287};
288
289static void load_segments(void)
290{
291 __asm__ __volatile__ (
292 "\tmovl %0,%%ds\n"
293 "\tmovl %0,%%es\n"
294 "\tmovl %0,%%ss\n"
295 "\tmovl %0,%%fs\n"
296 "\tmovl %0,%%gs\n"
297 : : "a" (__KERNEL_DS) : "memory"
298 );
299}
300
301#ifdef CONFIG_KEXEC_FILE
302/* Update purgatory as needed after various image segments have been prepared */
303static int arch_update_purgatory(struct kimage *image)
304{
305 int ret = 0;
306
307 if (!image->file_mode)
308 return 0;
309
310 /* Setup copying of backup region */
311 if (image->type == KEXEC_TYPE_CRASH) {
312 ret = kexec_purgatory_get_set_symbol(image,
313 "purgatory_backup_dest",
314 &image->arch.backup_load_addr,
315 sizeof(image->arch.backup_load_addr), 0);
316 if (ret)
317 return ret;
318
319 ret = kexec_purgatory_get_set_symbol(image,
320 "purgatory_backup_src",
321 &image->arch.backup_src_start,
322 sizeof(image->arch.backup_src_start), 0);
323 if (ret)
324 return ret;
325
326 ret = kexec_purgatory_get_set_symbol(image,
327 "purgatory_backup_sz",
328 &image->arch.backup_src_sz,
329 sizeof(image->arch.backup_src_sz), 0);
330 if (ret)
331 return ret;
332 }
333
334 return ret;
335}
336#else /* !CONFIG_KEXEC_FILE */
337static inline int arch_update_purgatory(struct kimage *image)
338{
339 return 0;
340}
341#endif /* CONFIG_KEXEC_FILE */
342
343int machine_kexec_prepare(struct kimage *image)
344{
345 unsigned long start_pgtable;
346 int result;
347
348 /* Calculate the offsets */
349 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
350
351 /* Setup the identity mapped 64bit page table */
352 result = init_pgtable(image, start_pgtable);
353 if (result)
354 return result;
355
356 /* update purgatory as needed */
357 result = arch_update_purgatory(image);
358 if (result)
359 return result;
360
361 return 0;
362}
363
364void machine_kexec_cleanup(struct kimage *image)
365{
366 free_transition_pgtable(image);
367}
368
369/*
370 * Do not allocate memory (or fail in any way) in machine_kexec().
371 * We are past the point of no return, committed to rebooting now.
372 */
373void machine_kexec(struct kimage *image)
374{
375 unsigned long page_list[PAGES_NR];
376 void *control_page;
377 int save_ftrace_enabled;
378
379#ifdef CONFIG_KEXEC_JUMP
380 if (image->preserve_context)
381 save_processor_state();
382#endif
383
384 save_ftrace_enabled = __ftrace_enabled_save();
385
386 /* Interrupts aren't acceptable while we reboot */
387 local_irq_disable();
388 hw_breakpoint_disable();
389
390 if (image->preserve_context) {
391#ifdef CONFIG_X86_IO_APIC
392 /*
393 * We need to put APICs in legacy mode so that we can
394 * get timer interrupts in second kernel. kexec/kdump
395 * paths already have calls to restore_boot_irq_mode()
396 * in one form or other. kexec jump path also need one.
397 */
398 clear_IO_APIC();
399 restore_boot_irq_mode();
400#endif
401 }
402
403 control_page = page_address(image->control_code_page) + PAGE_SIZE;
404 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
405
406 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
407 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
408 page_list[PA_TABLE_PAGE] =
409 (unsigned long)__pa(page_address(image->control_code_page));
410
411 if (image->type == KEXEC_TYPE_DEFAULT)
412 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
413 << PAGE_SHIFT);
414
415 /*
416 * The segment registers are funny things, they have both a
417 * visible and an invisible part. Whenever the visible part is
418 * set to a specific selector, the invisible part is loaded
419 * with from a table in memory. At no other time is the
420 * descriptor table in memory accessed.
421 *
422 * I take advantage of this here by force loading the
423 * segments, before I zap the gdt with an invalid value.
424 */
425 load_segments();
426 /*
427 * The gdt & idt are now invalid.
428 * If you want to load them you must set up your own idt & gdt.
429 */
430 set_gdt(phys_to_virt(0), 0);
431 set_idt(phys_to_virt(0), 0);
432
433 /* now call it */
434 image->start = relocate_kernel((unsigned long)image->head,
435 (unsigned long)page_list,
436 image->start,
437 image->preserve_context,
438 sme_active());
439
440#ifdef CONFIG_KEXEC_JUMP
441 if (image->preserve_context)
442 restore_processor_state();
443#endif
444
445 __ftrace_enabled_restore(save_ftrace_enabled);
446}
447
448void arch_crash_save_vmcoreinfo(void)
449{
450 u64 sme_mask = sme_me_mask;
451
452 VMCOREINFO_NUMBER(phys_base);
453 VMCOREINFO_SYMBOL(init_top_pgt);
454 vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
455 pgtable_l5_enabled());
456
457#ifdef CONFIG_NUMA
458 VMCOREINFO_SYMBOL(node_data);
459 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
460#endif
461 vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
462 kaslr_offset());
463 VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
464 VMCOREINFO_NUMBER(sme_mask);
465}
466
467/* arch-dependent functionality related to kexec file-based syscall */
468
469#ifdef CONFIG_KEXEC_FILE
470void *arch_kexec_kernel_image_load(struct kimage *image)
471{
472 vfree(image->arch.elf_headers);
473 image->arch.elf_headers = NULL;
474
475 if (!image->fops || !image->fops->load)
476 return ERR_PTR(-ENOEXEC);
477
478 return image->fops->load(image, image->kernel_buf,
479 image->kernel_buf_len, image->initrd_buf,
480 image->initrd_buf_len, image->cmdline_buf,
481 image->cmdline_buf_len);
482}
483
484/*
485 * Apply purgatory relocations.
486 *
487 * @pi: Purgatory to be relocated.
488 * @section: Section relocations applying to.
489 * @relsec: Section containing RELAs.
490 * @symtabsec: Corresponding symtab.
491 *
492 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
493 */
494int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
495 Elf_Shdr *section, const Elf_Shdr *relsec,
496 const Elf_Shdr *symtabsec)
497{
498 unsigned int i;
499 Elf64_Rela *rel;
500 Elf64_Sym *sym;
501 void *location;
502 unsigned long address, sec_base, value;
503 const char *strtab, *name, *shstrtab;
504 const Elf_Shdr *sechdrs;
505
506 /* String & section header string table */
507 sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
508 strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
509 shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
510
511 rel = (void *)pi->ehdr + relsec->sh_offset;
512
513 pr_debug("Applying relocate section %s to %u\n",
514 shstrtab + relsec->sh_name, relsec->sh_info);
515
516 for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {
517
518 /*
519 * rel[i].r_offset contains byte offset from beginning
520 * of section to the storage unit affected.
521 *
522 * This is location to update. This is temporary buffer
523 * where section is currently loaded. This will finally be
524 * loaded to a different address later, pointed to by
525 * ->sh_addr. kexec takes care of moving it
526 * (kexec_load_segment()).
527 */
528 location = pi->purgatory_buf;
529 location += section->sh_offset;
530 location += rel[i].r_offset;
531
532 /* Final address of the location */
533 address = section->sh_addr + rel[i].r_offset;
534
535 /*
536 * rel[i].r_info contains information about symbol table index
537 * w.r.t which relocation must be made and type of relocation
538 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
539 * these respectively.
540 */
541 sym = (void *)pi->ehdr + symtabsec->sh_offset;
542 sym += ELF64_R_SYM(rel[i].r_info);
543
544 if (sym->st_name)
545 name = strtab + sym->st_name;
546 else
547 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
548
549 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
550 name, sym->st_info, sym->st_shndx, sym->st_value,
551 sym->st_size);
552
553 if (sym->st_shndx == SHN_UNDEF) {
554 pr_err("Undefined symbol: %s\n", name);
555 return -ENOEXEC;
556 }
557
558 if (sym->st_shndx == SHN_COMMON) {
559 pr_err("symbol '%s' in common section\n", name);
560 return -ENOEXEC;
561 }
562
563 if (sym->st_shndx == SHN_ABS)
564 sec_base = 0;
565 else if (sym->st_shndx >= pi->ehdr->e_shnum) {
566 pr_err("Invalid section %d for symbol %s\n",
567 sym->st_shndx, name);
568 return -ENOEXEC;
569 } else
570 sec_base = pi->sechdrs[sym->st_shndx].sh_addr;
571
572 value = sym->st_value;
573 value += sec_base;
574 value += rel[i].r_addend;
575
576 switch (ELF64_R_TYPE(rel[i].r_info)) {
577 case R_X86_64_NONE:
578 break;
579 case R_X86_64_64:
580 *(u64 *)location = value;
581 break;
582 case R_X86_64_32:
583 *(u32 *)location = value;
584 if (value != *(u32 *)location)
585 goto overflow;
586 break;
587 case R_X86_64_32S:
588 *(s32 *)location = value;
589 if ((s64)value != *(s32 *)location)
590 goto overflow;
591 break;
592 case R_X86_64_PC32:
593 case R_X86_64_PLT32:
594 value -= (u64)address;
595 *(u32 *)location = value;
596 break;
597 default:
598 pr_err("Unknown rela relocation: %llu\n",
599 ELF64_R_TYPE(rel[i].r_info));
600 return -ENOEXEC;
601 }
602 }
603 return 0;
604
605overflow:
606 pr_err("Overflow in relocation type %d value 0x%lx\n",
607 (int)ELF64_R_TYPE(rel[i].r_info), value);
608 return -ENOEXEC;
609}
610#endif /* CONFIG_KEXEC_FILE */
611
612static int
613kexec_mark_range(unsigned long start, unsigned long end, bool protect)
614{
615 struct page *page;
616 unsigned int nr_pages;
617
618 /*
619 * For physical range: [start, end]. We must skip the unassigned
620 * crashk resource with zero-valued "end" member.
621 */
622 if (!end || start > end)
623 return 0;
624
625 page = pfn_to_page(start >> PAGE_SHIFT);
626 nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
627 if (protect)
628 return set_pages_ro(page, nr_pages);
629 else
630 return set_pages_rw(page, nr_pages);
631}
632
633static void kexec_mark_crashkres(bool protect)
634{
635 unsigned long control;
636
637 kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
638
639 /* Don't touch the control code page used in crash_kexec().*/
640 control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
641 /* Control code page is located in the 2nd page. */
642 kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
643 control += KEXEC_CONTROL_PAGE_SIZE;
644 kexec_mark_range(control, crashk_res.end, protect);
645}
646
647void arch_kexec_protect_crashkres(void)
648{
649 kexec_mark_crashkres(true);
650}
651
652void arch_kexec_unprotect_crashkres(void)
653{
654 kexec_mark_crashkres(false);
655}
656
657/*
658 * During a traditional boot under SME, SME will encrypt the kernel,
659 * so the SME kexec kernel also needs to be un-encrypted in order to
660 * replicate a normal SME boot.
661 *
662 * During a traditional boot under SEV, the kernel has already been
663 * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
664 * order to replicate a normal SEV boot.
665 */
666int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
667{
668 if (sev_active())
669 return 0;
670
671 /*
672 * If SME is active we need to be sure that kexec pages are
673 * not encrypted because when we boot to the new kernel the
674 * pages won't be accessed encrypted (initially).
675 */
676 return set_memory_decrypted((unsigned long)vaddr, pages);
677}
678
679void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
680{
681 if (sev_active())
682 return;
683
684 /*
685 * If SME is active we need to reset the pages back to being
686 * an encrypted mapping before freeing them.
687 */
688 set_memory_encrypted((unsigned long)vaddr, pages);
689}
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}