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