Commit | Line | Data |
---|---|---|
5234f5eb | 1 | /* |
835c34a1 | 2 | * handle transition of Linux booting another kernel |
5234f5eb EB |
3 | * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com> |
4 | * | |
5 | * This source code is licensed under the GNU General Public License, | |
6 | * Version 2. See the file COPYING for more details. | |
7 | */ | |
8 | ||
12db5562 VG |
9 | #define pr_fmt(fmt) "kexec: " fmt |
10 | ||
5234f5eb EB |
11 | #include <linux/mm.h> |
12 | #include <linux/kexec.h> | |
5234f5eb | 13 | #include <linux/string.h> |
5a0e3ad6 | 14 | #include <linux/gfp.h> |
5234f5eb | 15 | #include <linux/reboot.h> |
fd59d231 | 16 | #include <linux/numa.h> |
f43fdad8 | 17 | #include <linux/ftrace.h> |
fef3a7a1 | 18 | #include <linux/io.h> |
fee7b0d8 | 19 | #include <linux/suspend.h> |
f43fdad8 | 20 | |
9ebdc79f | 21 | #include <asm/init.h> |
5234f5eb | 22 | #include <asm/pgtable.h> |
5234f5eb EB |
23 | #include <asm/tlbflush.h> |
24 | #include <asm/mmu_context.h> | |
17f557e5 | 25 | #include <asm/debugreg.h> |
8bf27556 | 26 | |
cb105258 VG |
27 | static struct kexec_file_ops *kexec_file_loaders[] = { |
28 | NULL, | |
29 | }; | |
30 | ||
f5deb796 HY |
31 | static void free_transition_pgtable(struct kimage *image) |
32 | { | |
33 | free_page((unsigned long)image->arch.pud); | |
34 | free_page((unsigned long)image->arch.pmd); | |
35 | free_page((unsigned long)image->arch.pte); | |
36 | } | |
37 | ||
38 | static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) | |
39 | { | |
40 | pud_t *pud; | |
41 | pmd_t *pmd; | |
42 | pte_t *pte; | |
43 | unsigned long vaddr, paddr; | |
44 | int result = -ENOMEM; | |
45 | ||
46 | vaddr = (unsigned long)relocate_kernel; | |
47 | paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE); | |
48 | pgd += pgd_index(vaddr); | |
49 | if (!pgd_present(*pgd)) { | |
50 | pud = (pud_t *)get_zeroed_page(GFP_KERNEL); | |
51 | if (!pud) | |
52 | goto err; | |
53 | image->arch.pud = pud; | |
54 | set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE)); | |
55 | } | |
56 | pud = pud_offset(pgd, vaddr); | |
57 | if (!pud_present(*pud)) { | |
58 | pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL); | |
59 | if (!pmd) | |
60 | goto err; | |
61 | image->arch.pmd = pmd; | |
62 | set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); | |
63 | } | |
64 | pmd = pmd_offset(pud, vaddr); | |
65 | if (!pmd_present(*pmd)) { | |
66 | pte = (pte_t *)get_zeroed_page(GFP_KERNEL); | |
67 | if (!pte) | |
68 | goto err; | |
69 | image->arch.pte = pte; | |
70 | set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); | |
71 | } | |
72 | pte = pte_offset_kernel(pmd, vaddr); | |
73 | set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC)); | |
74 | return 0; | |
75 | err: | |
76 | free_transition_pgtable(image); | |
77 | return result; | |
78 | } | |
79 | ||
9ebdc79f YL |
80 | static void *alloc_pgt_page(void *data) |
81 | { | |
82 | struct kimage *image = (struct kimage *)data; | |
83 | struct page *page; | |
84 | void *p = NULL; | |
85 | ||
86 | page = kimage_alloc_control_pages(image, 0); | |
87 | if (page) { | |
88 | p = page_address(page); | |
89 | clear_page(p); | |
90 | } | |
91 | ||
92 | return p; | |
93 | } | |
94 | ||
5234f5eb EB |
95 | static int init_pgtable(struct kimage *image, unsigned long start_pgtable) |
96 | { | |
9ebdc79f YL |
97 | struct x86_mapping_info info = { |
98 | .alloc_pgt_page = alloc_pgt_page, | |
99 | .context = image, | |
100 | .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, | |
101 | }; | |
084d1283 | 102 | unsigned long mstart, mend; |
8bf27556 | 103 | pgd_t *level4p; |
f5deb796 | 104 | int result; |
084d1283 YL |
105 | int i; |
106 | ||
8bf27556 | 107 | level4p = (pgd_t *)__va(start_pgtable); |
9ebdc79f | 108 | clear_page(level4p); |
0e691cf8 YL |
109 | for (i = 0; i < nr_pfn_mapped; i++) { |
110 | mstart = pfn_mapped[i].start << PAGE_SHIFT; | |
111 | mend = pfn_mapped[i].end << PAGE_SHIFT; | |
112 | ||
113 | result = kernel_ident_mapping_init(&info, | |
114 | level4p, mstart, mend); | |
115 | if (result) | |
116 | return result; | |
117 | } | |
084d1283 | 118 | |
53594547 | 119 | /* |
084d1283 YL |
120 | * segments's mem ranges could be outside 0 ~ max_pfn, |
121 | * for example when jump back to original kernel from kexeced kernel. | |
122 | * or first kernel is booted with user mem map, and second kernel | |
123 | * could be loaded out of that range. | |
53594547 | 124 | */ |
084d1283 YL |
125 | for (i = 0; i < image->nr_segments; i++) { |
126 | mstart = image->segment[i].mem; | |
127 | mend = mstart + image->segment[i].memsz; | |
128 | ||
9ebdc79f YL |
129 | result = kernel_ident_mapping_init(&info, |
130 | level4p, mstart, mend); | |
084d1283 YL |
131 | |
132 | if (result) | |
133 | return result; | |
134 | } | |
135 | ||
f5deb796 | 136 | return init_transition_pgtable(image, level4p); |
5234f5eb EB |
137 | } |
138 | ||
139 | static void set_idt(void *newidt, u16 limit) | |
140 | { | |
36c4fd23 | 141 | struct desc_ptr curidt; |
5234f5eb EB |
142 | |
143 | /* x86-64 supports unaliged loads & stores */ | |
36c4fd23 EB |
144 | curidt.size = limit; |
145 | curidt.address = (unsigned long)newidt; | |
5234f5eb EB |
146 | |
147 | __asm__ __volatile__ ( | |
36c4fd23 EB |
148 | "lidtq %0\n" |
149 | : : "m" (curidt) | |
5234f5eb EB |
150 | ); |
151 | }; | |
152 | ||
153 | ||
154 | static void set_gdt(void *newgdt, u16 limit) | |
155 | { | |
36c4fd23 | 156 | struct desc_ptr curgdt; |
5234f5eb EB |
157 | |
158 | /* x86-64 supports unaligned loads & stores */ | |
36c4fd23 EB |
159 | curgdt.size = limit; |
160 | curgdt.address = (unsigned long)newgdt; | |
5234f5eb EB |
161 | |
162 | __asm__ __volatile__ ( | |
36c4fd23 EB |
163 | "lgdtq %0\n" |
164 | : : "m" (curgdt) | |
5234f5eb EB |
165 | ); |
166 | }; | |
167 | ||
168 | static void load_segments(void) | |
169 | { | |
170 | __asm__ __volatile__ ( | |
36c4fd23 EB |
171 | "\tmovl %0,%%ds\n" |
172 | "\tmovl %0,%%es\n" | |
173 | "\tmovl %0,%%ss\n" | |
174 | "\tmovl %0,%%fs\n" | |
175 | "\tmovl %0,%%gs\n" | |
2ec5e3a8 | 176 | : : "a" (__KERNEL_DS) : "memory" |
5234f5eb | 177 | ); |
5234f5eb EB |
178 | } |
179 | ||
5234f5eb EB |
180 | int machine_kexec_prepare(struct kimage *image) |
181 | { | |
4bfaaef0 | 182 | unsigned long start_pgtable; |
5234f5eb EB |
183 | int result; |
184 | ||
185 | /* Calculate the offsets */ | |
72414d3f | 186 | start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; |
5234f5eb EB |
187 | |
188 | /* Setup the identity mapped 64bit page table */ | |
189 | result = init_pgtable(image, start_pgtable); | |
72414d3f | 190 | if (result) |
5234f5eb | 191 | return result; |
5234f5eb | 192 | |
5234f5eb EB |
193 | return 0; |
194 | } | |
195 | ||
196 | void machine_kexec_cleanup(struct kimage *image) | |
197 | { | |
f5deb796 | 198 | free_transition_pgtable(image); |
5234f5eb EB |
199 | } |
200 | ||
201 | /* | |
202 | * Do not allocate memory (or fail in any way) in machine_kexec(). | |
203 | * We are past the point of no return, committed to rebooting now. | |
204 | */ | |
3ab83521 | 205 | void machine_kexec(struct kimage *image) |
5234f5eb | 206 | { |
4bfaaef0 MD |
207 | unsigned long page_list[PAGES_NR]; |
208 | void *control_page; | |
fee7b0d8 | 209 | int save_ftrace_enabled; |
5234f5eb | 210 | |
fee7b0d8 | 211 | #ifdef CONFIG_KEXEC_JUMP |
6407df5c | 212 | if (image->preserve_context) |
fee7b0d8 HY |
213 | save_processor_state(); |
214 | #endif | |
215 | ||
216 | save_ftrace_enabled = __ftrace_enabled_save(); | |
f43fdad8 | 217 | |
5234f5eb EB |
218 | /* Interrupts aren't acceptable while we reboot */ |
219 | local_irq_disable(); | |
17f557e5 | 220 | hw_breakpoint_disable(); |
5234f5eb | 221 | |
fee7b0d8 HY |
222 | if (image->preserve_context) { |
223 | #ifdef CONFIG_X86_IO_APIC | |
224 | /* | |
225 | * We need to put APICs in legacy mode so that we can | |
226 | * get timer interrupts in second kernel. kexec/kdump | |
227 | * paths already have calls to disable_IO_APIC() in | |
228 | * one form or other. kexec jump path also need | |
229 | * one. | |
230 | */ | |
231 | disable_IO_APIC(); | |
232 | #endif | |
233 | } | |
234 | ||
4bfaaef0 | 235 | control_page = page_address(image->control_code_page) + PAGE_SIZE; |
fee7b0d8 | 236 | memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE); |
4bfaaef0 | 237 | |
e3ebadd9 | 238 | page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); |
fee7b0d8 | 239 | page_list[VA_CONTROL_PAGE] = (unsigned long)control_page; |
4bfaaef0 MD |
240 | page_list[PA_TABLE_PAGE] = |
241 | (unsigned long)__pa(page_address(image->control_code_page)); | |
5234f5eb | 242 | |
fee7b0d8 HY |
243 | if (image->type == KEXEC_TYPE_DEFAULT) |
244 | page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page) | |
245 | << PAGE_SHIFT); | |
246 | ||
fef3a7a1 HY |
247 | /* |
248 | * The segment registers are funny things, they have both a | |
2a8a3d5b EB |
249 | * visible and an invisible part. Whenever the visible part is |
250 | * set to a specific selector, the invisible part is loaded | |
251 | * with from a table in memory. At no other time is the | |
252 | * descriptor table in memory accessed. | |
5234f5eb EB |
253 | * |
254 | * I take advantage of this here by force loading the | |
255 | * segments, before I zap the gdt with an invalid value. | |
256 | */ | |
257 | load_segments(); | |
fef3a7a1 HY |
258 | /* |
259 | * The gdt & idt are now invalid. | |
5234f5eb EB |
260 | * If you want to load them you must set up your own idt & gdt. |
261 | */ | |
fef3a7a1 HY |
262 | set_gdt(phys_to_virt(0), 0); |
263 | set_idt(phys_to_virt(0), 0); | |
4bfaaef0 | 264 | |
5234f5eb | 265 | /* now call it */ |
fee7b0d8 HY |
266 | image->start = relocate_kernel((unsigned long)image->head, |
267 | (unsigned long)page_list, | |
268 | image->start, | |
269 | image->preserve_context); | |
270 | ||
271 | #ifdef CONFIG_KEXEC_JUMP | |
6407df5c | 272 | if (image->preserve_context) |
fee7b0d8 HY |
273 | restore_processor_state(); |
274 | #endif | |
275 | ||
276 | __ftrace_enabled_restore(save_ftrace_enabled); | |
5234f5eb | 277 | } |
2c8c0e6b | 278 | |
fd59d231 KO |
279 | void arch_crash_save_vmcoreinfo(void) |
280 | { | |
629c8b4c | 281 | VMCOREINFO_SYMBOL(phys_base); |
69243f91 | 282 | VMCOREINFO_SYMBOL(init_level4_pgt); |
92df5c3e KO |
283 | |
284 | #ifdef CONFIG_NUMA | |
285 | VMCOREINFO_SYMBOL(node_data); | |
286 | VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); | |
287 | #endif | |
b6085a86 ES |
288 | vmcoreinfo_append_str("KERNELOFFSET=%lx\n", |
289 | (unsigned long)&_text - __START_KERNEL); | |
fd59d231 KO |
290 | } |
291 | ||
cb105258 VG |
292 | /* arch-dependent functionality related to kexec file-based syscall */ |
293 | ||
294 | int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, | |
295 | unsigned long buf_len) | |
296 | { | |
297 | int i, ret = -ENOEXEC; | |
298 | struct kexec_file_ops *fops; | |
299 | ||
300 | for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) { | |
301 | fops = kexec_file_loaders[i]; | |
302 | if (!fops || !fops->probe) | |
303 | continue; | |
304 | ||
305 | ret = fops->probe(buf, buf_len); | |
306 | if (!ret) { | |
307 | image->fops = fops; | |
308 | return ret; | |
309 | } | |
310 | } | |
311 | ||
312 | return ret; | |
313 | } | |
314 | ||
315 | void *arch_kexec_kernel_image_load(struct kimage *image) | |
316 | { | |
317 | if (!image->fops || !image->fops->load) | |
318 | return ERR_PTR(-ENOEXEC); | |
319 | ||
320 | return image->fops->load(image, image->kernel_buf, | |
321 | image->kernel_buf_len, image->initrd_buf, | |
322 | image->initrd_buf_len, image->cmdline_buf, | |
323 | image->cmdline_buf_len); | |
324 | } | |
325 | ||
326 | int arch_kimage_file_post_load_cleanup(struct kimage *image) | |
327 | { | |
328 | if (!image->fops || !image->fops->cleanup) | |
329 | return 0; | |
330 | ||
331 | return image->fops->cleanup(image); | |
332 | } | |
12db5562 VG |
333 | |
334 | /* | |
335 | * Apply purgatory relocations. | |
336 | * | |
337 | * ehdr: Pointer to elf headers | |
338 | * sechdrs: Pointer to section headers. | |
339 | * relsec: section index of SHT_RELA section. | |
340 | * | |
341 | * TODO: Some of the code belongs to generic code. Move that in kexec.c. | |
342 | */ | |
343 | int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr, | |
344 | Elf64_Shdr *sechdrs, unsigned int relsec) | |
345 | { | |
346 | unsigned int i; | |
347 | Elf64_Rela *rel; | |
348 | Elf64_Sym *sym; | |
349 | void *location; | |
350 | Elf64_Shdr *section, *symtabsec; | |
351 | unsigned long address, sec_base, value; | |
352 | const char *strtab, *name, *shstrtab; | |
353 | ||
354 | /* | |
355 | * ->sh_offset has been modified to keep the pointer to section | |
356 | * contents in memory | |
357 | */ | |
358 | rel = (void *)sechdrs[relsec].sh_offset; | |
359 | ||
360 | /* Section to which relocations apply */ | |
361 | section = &sechdrs[sechdrs[relsec].sh_info]; | |
362 | ||
363 | pr_debug("Applying relocate section %u to %u\n", relsec, | |
364 | sechdrs[relsec].sh_info); | |
365 | ||
366 | /* Associated symbol table */ | |
367 | symtabsec = &sechdrs[sechdrs[relsec].sh_link]; | |
368 | ||
369 | /* String table */ | |
370 | if (symtabsec->sh_link >= ehdr->e_shnum) { | |
371 | /* Invalid strtab section number */ | |
372 | pr_err("Invalid string table section index %d\n", | |
373 | symtabsec->sh_link); | |
374 | return -ENOEXEC; | |
375 | } | |
376 | ||
377 | strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset; | |
378 | ||
379 | /* section header string table */ | |
380 | shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset; | |
381 | ||
382 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
383 | ||
384 | /* | |
385 | * rel[i].r_offset contains byte offset from beginning | |
386 | * of section to the storage unit affected. | |
387 | * | |
388 | * This is location to update (->sh_offset). This is temporary | |
389 | * buffer where section is currently loaded. This will finally | |
390 | * be loaded to a different address later, pointed to by | |
391 | * ->sh_addr. kexec takes care of moving it | |
392 | * (kexec_load_segment()). | |
393 | */ | |
394 | location = (void *)(section->sh_offset + rel[i].r_offset); | |
395 | ||
396 | /* Final address of the location */ | |
397 | address = section->sh_addr + rel[i].r_offset; | |
398 | ||
399 | /* | |
400 | * rel[i].r_info contains information about symbol table index | |
401 | * w.r.t which relocation must be made and type of relocation | |
402 | * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get | |
403 | * these respectively. | |
404 | */ | |
405 | sym = (Elf64_Sym *)symtabsec->sh_offset + | |
406 | ELF64_R_SYM(rel[i].r_info); | |
407 | ||
408 | if (sym->st_name) | |
409 | name = strtab + sym->st_name; | |
410 | else | |
411 | name = shstrtab + sechdrs[sym->st_shndx].sh_name; | |
412 | ||
413 | pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n", | |
414 | name, sym->st_info, sym->st_shndx, sym->st_value, | |
415 | sym->st_size); | |
416 | ||
417 | if (sym->st_shndx == SHN_UNDEF) { | |
418 | pr_err("Undefined symbol: %s\n", name); | |
419 | return -ENOEXEC; | |
420 | } | |
421 | ||
422 | if (sym->st_shndx == SHN_COMMON) { | |
423 | pr_err("symbol '%s' in common section\n", name); | |
424 | return -ENOEXEC; | |
425 | } | |
426 | ||
427 | if (sym->st_shndx == SHN_ABS) | |
428 | sec_base = 0; | |
429 | else if (sym->st_shndx >= ehdr->e_shnum) { | |
430 | pr_err("Invalid section %d for symbol %s\n", | |
431 | sym->st_shndx, name); | |
432 | return -ENOEXEC; | |
433 | } else | |
434 | sec_base = sechdrs[sym->st_shndx].sh_addr; | |
435 | ||
436 | value = sym->st_value; | |
437 | value += sec_base; | |
438 | value += rel[i].r_addend; | |
439 | ||
440 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
441 | case R_X86_64_NONE: | |
442 | break; | |
443 | case R_X86_64_64: | |
444 | *(u64 *)location = value; | |
445 | break; | |
446 | case R_X86_64_32: | |
447 | *(u32 *)location = value; | |
448 | if (value != *(u32 *)location) | |
449 | goto overflow; | |
450 | break; | |
451 | case R_X86_64_32S: | |
452 | *(s32 *)location = value; | |
453 | if ((s64)value != *(s32 *)location) | |
454 | goto overflow; | |
455 | break; | |
456 | case R_X86_64_PC32: | |
457 | value -= (u64)address; | |
458 | *(u32 *)location = value; | |
459 | break; | |
460 | default: | |
461 | pr_err("Unknown rela relocation: %llu\n", | |
462 | ELF64_R_TYPE(rel[i].r_info)); | |
463 | return -ENOEXEC; | |
464 | } | |
465 | } | |
466 | return 0; | |
467 | ||
468 | overflow: | |
469 | pr_err("Overflow in relocation type %d value 0x%lx\n", | |
470 | (int)ELF64_R_TYPE(rel[i].r_info), value); | |
471 | return -ENOEXEC; | |
472 | } |