2 * handle transition of Linux booting another kernel
3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
9 #define pr_fmt(fmt) "kexec: " fmt
12 #include <linux/kexec.h>
13 #include <linux/string.h>
14 #include <linux/gfp.h>
15 #include <linux/reboot.h>
16 #include <linux/numa.h>
17 #include <linux/ftrace.h>
19 #include <linux/suspend.h>
22 #include <asm/pgtable.h>
23 #include <asm/tlbflush.h>
24 #include <asm/mmu_context.h>
25 #include <asm/debugreg.h>
26 #include <asm/kexec-bzimage64.h>
28 #ifdef CONFIG_KEXEC_FILE
29 static struct kexec_file_ops *kexec_file_loaders[] = {
34 static void free_transition_pgtable(struct kimage *image)
36 free_page((unsigned long)image->arch.pud);
37 free_page((unsigned long)image->arch.pmd);
38 free_page((unsigned long)image->arch.pte);
41 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
46 unsigned long vaddr, paddr;
49 vaddr = (unsigned long)relocate_kernel;
50 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
51 pgd += pgd_index(vaddr);
52 if (!pgd_present(*pgd)) {
53 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
56 image->arch.pud = pud;
57 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
59 pud = pud_offset(pgd, vaddr);
60 if (!pud_present(*pud)) {
61 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
64 image->arch.pmd = pmd;
65 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
67 pmd = pmd_offset(pud, vaddr);
68 if (!pmd_present(*pmd)) {
69 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
72 image->arch.pte = pte;
73 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
75 pte = pte_offset_kernel(pmd, vaddr);
76 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
79 free_transition_pgtable(image);
83 static void *alloc_pgt_page(void *data)
85 struct kimage *image = (struct kimage *)data;
89 page = kimage_alloc_control_pages(image, 0);
91 p = page_address(page);
98 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
100 struct x86_mapping_info info = {
101 .alloc_pgt_page = alloc_pgt_page,
103 .pmd_flag = __PAGE_KERNEL_LARGE_EXEC,
105 unsigned long mstart, mend;
110 level4p = (pgd_t *)__va(start_pgtable);
112 for (i = 0; i < nr_pfn_mapped; i++) {
113 mstart = pfn_mapped[i].start << PAGE_SHIFT;
114 mend = pfn_mapped[i].end << PAGE_SHIFT;
116 result = kernel_ident_mapping_init(&info,
117 level4p, mstart, mend);
123 * segments's mem ranges could be outside 0 ~ max_pfn,
124 * for example when jump back to original kernel from kexeced kernel.
125 * or first kernel is booted with user mem map, and second kernel
126 * could be loaded out of that range.
128 for (i = 0; i < image->nr_segments; i++) {
129 mstart = image->segment[i].mem;
130 mend = mstart + image->segment[i].memsz;
132 result = kernel_ident_mapping_init(&info,
133 level4p, mstart, mend);
139 return init_transition_pgtable(image, level4p);
142 static void set_idt(void *newidt, u16 limit)
144 struct desc_ptr curidt;
146 /* x86-64 supports unaliged loads & stores */
148 curidt.address = (unsigned long)newidt;
150 __asm__ __volatile__ (
157 static void set_gdt(void *newgdt, u16 limit)
159 struct desc_ptr curgdt;
161 /* x86-64 supports unaligned loads & stores */
163 curgdt.address = (unsigned long)newgdt;
165 __asm__ __volatile__ (
171 static void load_segments(void)
173 __asm__ __volatile__ (
179 : : "a" (__KERNEL_DS) : "memory"
183 #ifdef CONFIG_KEXEC_FILE
184 /* Update purgatory as needed after various image segments have been prepared */
185 static int arch_update_purgatory(struct kimage *image)
189 if (!image->file_mode)
192 /* Setup copying of backup region */
193 if (image->type == KEXEC_TYPE_CRASH) {
194 ret = kexec_purgatory_get_set_symbol(image, "backup_dest",
195 &image->arch.backup_load_addr,
196 sizeof(image->arch.backup_load_addr), 0);
200 ret = kexec_purgatory_get_set_symbol(image, "backup_src",
201 &image->arch.backup_src_start,
202 sizeof(image->arch.backup_src_start), 0);
206 ret = kexec_purgatory_get_set_symbol(image, "backup_sz",
207 &image->arch.backup_src_sz,
208 sizeof(image->arch.backup_src_sz), 0);
215 #else /* !CONFIG_KEXEC_FILE */
216 static inline int arch_update_purgatory(struct kimage *image)
220 #endif /* CONFIG_KEXEC_FILE */
222 int machine_kexec_prepare(struct kimage *image)
224 unsigned long start_pgtable;
227 /* Calculate the offsets */
228 start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
230 /* Setup the identity mapped 64bit page table */
231 result = init_pgtable(image, start_pgtable);
235 /* update purgatory as needed */
236 result = arch_update_purgatory(image);
243 void machine_kexec_cleanup(struct kimage *image)
245 free_transition_pgtable(image);
249 * Do not allocate memory (or fail in any way) in machine_kexec().
250 * We are past the point of no return, committed to rebooting now.
252 void machine_kexec(struct kimage *image)
254 unsigned long page_list[PAGES_NR];
256 int save_ftrace_enabled;
258 #ifdef CONFIG_KEXEC_JUMP
259 if (image->preserve_context)
260 save_processor_state();
263 save_ftrace_enabled = __ftrace_enabled_save();
265 /* Interrupts aren't acceptable while we reboot */
267 hw_breakpoint_disable();
269 if (image->preserve_context) {
270 #ifdef CONFIG_X86_IO_APIC
272 * We need to put APICs in legacy mode so that we can
273 * get timer interrupts in second kernel. kexec/kdump
274 * paths already have calls to disable_IO_APIC() in
275 * one form or other. kexec jump path also need
282 control_page = page_address(image->control_code_page) + PAGE_SIZE;
283 memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
285 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
286 page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
287 page_list[PA_TABLE_PAGE] =
288 (unsigned long)__pa(page_address(image->control_code_page));
290 if (image->type == KEXEC_TYPE_DEFAULT)
291 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
295 * The segment registers are funny things, they have both a
296 * visible and an invisible part. Whenever the visible part is
297 * set to a specific selector, the invisible part is loaded
298 * with from a table in memory. At no other time is the
299 * descriptor table in memory accessed.
301 * I take advantage of this here by force loading the
302 * segments, before I zap the gdt with an invalid value.
306 * The gdt & idt are now invalid.
307 * If you want to load them you must set up your own idt & gdt.
309 set_gdt(phys_to_virt(0), 0);
310 set_idt(phys_to_virt(0), 0);
313 image->start = relocate_kernel((unsigned long)image->head,
314 (unsigned long)page_list,
316 image->preserve_context);
318 #ifdef CONFIG_KEXEC_JUMP
319 if (image->preserve_context)
320 restore_processor_state();
323 __ftrace_enabled_restore(save_ftrace_enabled);
326 void arch_crash_save_vmcoreinfo(void)
328 VMCOREINFO_SYMBOL(phys_base);
329 VMCOREINFO_SYMBOL(init_level4_pgt);
332 VMCOREINFO_SYMBOL(node_data);
333 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
335 vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
336 (unsigned long)&_text - __START_KERNEL);
339 /* arch-dependent functionality related to kexec file-based syscall */
341 #ifdef CONFIG_KEXEC_FILE
342 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
343 unsigned long buf_len)
345 int i, ret = -ENOEXEC;
346 struct kexec_file_ops *fops;
348 for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
349 fops = kexec_file_loaders[i];
350 if (!fops || !fops->probe)
353 ret = fops->probe(buf, buf_len);
363 void *arch_kexec_kernel_image_load(struct kimage *image)
365 vfree(image->arch.elf_headers);
366 image->arch.elf_headers = NULL;
368 if (!image->fops || !image->fops->load)
369 return ERR_PTR(-ENOEXEC);
371 return image->fops->load(image, image->kernel_buf,
372 image->kernel_buf_len, image->initrd_buf,
373 image->initrd_buf_len, image->cmdline_buf,
374 image->cmdline_buf_len);
377 int arch_kimage_file_post_load_cleanup(struct kimage *image)
379 if (!image->fops || !image->fops->cleanup)
382 return image->fops->cleanup(image->image_loader_data);
385 int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
386 unsigned long kernel_len)
388 if (!image->fops || !image->fops->verify_sig) {
389 pr_debug("kernel loader does not support signature verification.");
390 return -EKEYREJECTED;
393 return image->fops->verify_sig(kernel, kernel_len);
397 * Apply purgatory relocations.
399 * ehdr: Pointer to elf headers
400 * sechdrs: Pointer to section headers.
401 * relsec: section index of SHT_RELA section.
403 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
405 int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
406 Elf64_Shdr *sechdrs, unsigned int relsec)
412 Elf64_Shdr *section, *symtabsec;
413 unsigned long address, sec_base, value;
414 const char *strtab, *name, *shstrtab;
417 * ->sh_offset has been modified to keep the pointer to section
420 rel = (void *)sechdrs[relsec].sh_offset;
422 /* Section to which relocations apply */
423 section = &sechdrs[sechdrs[relsec].sh_info];
425 pr_debug("Applying relocate section %u to %u\n", relsec,
426 sechdrs[relsec].sh_info);
428 /* Associated symbol table */
429 symtabsec = &sechdrs[sechdrs[relsec].sh_link];
432 if (symtabsec->sh_link >= ehdr->e_shnum) {
433 /* Invalid strtab section number */
434 pr_err("Invalid string table section index %d\n",
439 strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;
441 /* section header string table */
442 shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;
444 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
447 * rel[i].r_offset contains byte offset from beginning
448 * of section to the storage unit affected.
450 * This is location to update (->sh_offset). This is temporary
451 * buffer where section is currently loaded. This will finally
452 * be loaded to a different address later, pointed to by
453 * ->sh_addr. kexec takes care of moving it
454 * (kexec_load_segment()).
456 location = (void *)(section->sh_offset + rel[i].r_offset);
458 /* Final address of the location */
459 address = section->sh_addr + rel[i].r_offset;
462 * rel[i].r_info contains information about symbol table index
463 * w.r.t which relocation must be made and type of relocation
464 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
465 * these respectively.
467 sym = (Elf64_Sym *)symtabsec->sh_offset +
468 ELF64_R_SYM(rel[i].r_info);
471 name = strtab + sym->st_name;
473 name = shstrtab + sechdrs[sym->st_shndx].sh_name;
475 pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
476 name, sym->st_info, sym->st_shndx, sym->st_value,
479 if (sym->st_shndx == SHN_UNDEF) {
480 pr_err("Undefined symbol: %s\n", name);
484 if (sym->st_shndx == SHN_COMMON) {
485 pr_err("symbol '%s' in common section\n", name);
489 if (sym->st_shndx == SHN_ABS)
491 else if (sym->st_shndx >= ehdr->e_shnum) {
492 pr_err("Invalid section %d for symbol %s\n",
493 sym->st_shndx, name);
496 sec_base = sechdrs[sym->st_shndx].sh_addr;
498 value = sym->st_value;
500 value += rel[i].r_addend;
502 switch (ELF64_R_TYPE(rel[i].r_info)) {
506 *(u64 *)location = value;
509 *(u32 *)location = value;
510 if (value != *(u32 *)location)
514 *(s32 *)location = value;
515 if ((s64)value != *(s32 *)location)
519 value -= (u64)address;
520 *(u32 *)location = value;
523 pr_err("Unknown rela relocation: %llu\n",
524 ELF64_R_TYPE(rel[i].r_info));
531 pr_err("Overflow in relocation type %d value 0x%lx\n",
532 (int)ELF64_R_TYPE(rel[i].r_info), value);
535 #endif /* CONFIG_KEXEC_FILE */