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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
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
511#ifdef CONFIG_CRASH_DUMP
512
513static int
514kexec_mark_range(unsigned long start, unsigned long end, bool protect)
515{
516 struct page *page;
517 unsigned int nr_pages;
518
519 /*
520 * For physical range: [start, end]. We must skip the unassigned
521 * crashk resource with zero-valued "end" member.
522 */
523 if (!end || start > end)
524 return 0;
525
526 page = pfn_to_page(start >> PAGE_SHIFT);
527 nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
528 if (protect)
529 return set_pages_ro(page, nr_pages);
530 else
531 return set_pages_rw(page, nr_pages);
532}
533
534static void kexec_mark_crashkres(bool protect)
535{
536 unsigned long control;
537
538 kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
539
540 /* Don't touch the control code page used in crash_kexec().*/
541 control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
542 /* Control code page is located in the 2nd page. */
543 kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
544 control += KEXEC_CONTROL_PAGE_SIZE;
545 kexec_mark_range(control, crashk_res.end, protect);
546}
547
548void arch_kexec_protect_crashkres(void)
549{
550 kexec_mark_crashkres(true);
551}
552
553void arch_kexec_unprotect_crashkres(void)
554{
555 kexec_mark_crashkres(false);
556}
557#endif
558
559/*
560 * During a traditional boot under SME, SME will encrypt the kernel,
561 * so the SME kexec kernel also needs to be un-encrypted in order to
562 * replicate a normal SME boot.
563 *
564 * During a traditional boot under SEV, the kernel has already been
565 * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
566 * order to replicate a normal SEV boot.
567 */
568int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
569{
570 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
571 return 0;
572
573 /*
574 * If host memory encryption is active we need to be sure that kexec
575 * pages are not encrypted because when we boot to the new kernel the
576 * pages won't be accessed encrypted (initially).
577 */
578 return set_memory_decrypted((unsigned long)vaddr, pages);
579}
580
581void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
582{
583 if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
584 return;
585
586 /*
587 * If host memory encryption is active we need to reset the pages back
588 * to being an encrypted mapping before freeing them.
589 */
590 set_memory_encrypted((unsigned long)vaddr, pages);
591}