machine_kexec_64.c 12.9 KB
Newer Older
1
/*
Dave Jones's avatar
Dave Jones committed
2
 * handle transition of Linux booting another kernel
3 4 5 6 7 8
 * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

9 10
#define pr_fmt(fmt)	"kexec: " fmt

11 12 13
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/string.h>
14
#include <linux/gfp.h>
15
#include <linux/reboot.h>
Ken'ichi Ohmichi's avatar
Ken'ichi Ohmichi committed
16
#include <linux/numa.h>
Ingo Molnar's avatar
Ingo Molnar committed
17
#include <linux/ftrace.h>
18
#include <linux/io.h>
19
#include <linux/suspend.h>
Ingo Molnar's avatar
Ingo Molnar committed
20

21
#include <asm/init.h>
22 23 24
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
25
#include <asm/io_apic.h>
26
#include <asm/debugreg.h>
27
#include <asm/kexec-bzimage64.h>
28

29
#ifdef CONFIG_KEXEC_FILE
30
static struct kexec_file_ops *kexec_file_loaders[] = {
31
		&kexec_bzImage64_ops,
32
};
33
#endif
34

35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83
static void free_transition_pgtable(struct kimage *image)
{
	free_page((unsigned long)image->arch.pud);
	free_page((unsigned long)image->arch.pmd);
	free_page((unsigned long)image->arch.pte);
}

static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
{
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long vaddr, paddr;
	int result = -ENOMEM;

	vaddr = (unsigned long)relocate_kernel;
	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
	pgd += pgd_index(vaddr);
	if (!pgd_present(*pgd)) {
		pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
		if (!pud)
			goto err;
		image->arch.pud = pud;
		set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
	}
	pud = pud_offset(pgd, vaddr);
	if (!pud_present(*pud)) {
		pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
		if (!pmd)
			goto err;
		image->arch.pmd = pmd;
		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
	}
	pmd = pmd_offset(pud, vaddr);
	if (!pmd_present(*pmd)) {
		pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
		if (!pte)
			goto err;
		image->arch.pte = pte;
		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
	}
	pte = pte_offset_kernel(pmd, vaddr);
	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
	return 0;
err:
	free_transition_pgtable(image);
	return result;
}

84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
static void *alloc_pgt_page(void *data)
{
	struct kimage *image = (struct kimage *)data;
	struct page *page;
	void *p = NULL;

	page = kimage_alloc_control_pages(image, 0);
	if (page) {
		p = page_address(page);
		clear_page(p);
	}

	return p;
}

99 100
static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
{
101 102 103 104 105
	struct x86_mapping_info info = {
		.alloc_pgt_page	= alloc_pgt_page,
		.context	= image,
		.pmd_flag	= __PAGE_KERNEL_LARGE_EXEC,
	};
106
	unsigned long mstart, mend;
107
	pgd_t *level4p;
108
	int result;
109 110
	int i;

111
	level4p = (pgd_t *)__va(start_pgtable);
112
	clear_page(level4p);
113 114 115 116 117 118 119 120 121
	for (i = 0; i < nr_pfn_mapped; i++) {
		mstart = pfn_mapped[i].start << PAGE_SHIFT;
		mend   = pfn_mapped[i].end << PAGE_SHIFT;

		result = kernel_ident_mapping_init(&info,
						 level4p, mstart, mend);
		if (result)
			return result;
	}
122

123
	/*
124 125 126 127
	 * segments's mem ranges could be outside 0 ~ max_pfn,
	 * for example when jump back to original kernel from kexeced kernel.
	 * or first kernel is booted with user mem map, and second kernel
	 * could be loaded out of that range.
128
	 */
129 130 131 132
	for (i = 0; i < image->nr_segments; i++) {
		mstart = image->segment[i].mem;
		mend   = mstart + image->segment[i].memsz;

133 134
		result = kernel_ident_mapping_init(&info,
						 level4p, mstart, mend);
135 136 137 138 139

		if (result)
			return result;
	}

140
	return init_transition_pgtable(image, level4p);
141 142 143 144
}

static void set_idt(void *newidt, u16 limit)
{
145
	struct desc_ptr curidt;
146 147

	/* x86-64 supports unaliged loads & stores */
148 149
	curidt.size    = limit;
	curidt.address = (unsigned long)newidt;
150 151

	__asm__ __volatile__ (
152 153
		"lidtq %0\n"
		: : "m" (curidt)
154 155 156 157 158 159
		);
};


static void set_gdt(void *newgdt, u16 limit)
{
160
	struct desc_ptr curgdt;
161 162

	/* x86-64 supports unaligned loads & stores */
163 164
	curgdt.size    = limit;
	curgdt.address = (unsigned long)newgdt;
165 166

	__asm__ __volatile__ (
167 168
		"lgdtq %0\n"
		: : "m" (curgdt)
169 170 171 172 173 174
		);
};

static void load_segments(void)
{
	__asm__ __volatile__ (
175 176 177 178 179
		"\tmovl %0,%%ds\n"
		"\tmovl %0,%%es\n"
		"\tmovl %0,%%ss\n"
		"\tmovl %0,%%fs\n"
		"\tmovl %0,%%gs\n"
Michael Matz's avatar
Michael Matz committed
180
		: : "a" (__KERNEL_DS) : "memory"
181 182 183
		);
}

184
#ifdef CONFIG_KEXEC_FILE
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
/* Update purgatory as needed after various image segments have been prepared */
static int arch_update_purgatory(struct kimage *image)
{
	int ret = 0;

	if (!image->file_mode)
		return 0;

	/* Setup copying of backup region */
	if (image->type == KEXEC_TYPE_CRASH) {
		ret = kexec_purgatory_get_set_symbol(image, "backup_dest",
				&image->arch.backup_load_addr,
				sizeof(image->arch.backup_load_addr), 0);
		if (ret)
			return ret;

		ret = kexec_purgatory_get_set_symbol(image, "backup_src",
				&image->arch.backup_src_start,
				sizeof(image->arch.backup_src_start), 0);
		if (ret)
			return ret;

		ret = kexec_purgatory_get_set_symbol(image, "backup_sz",
				&image->arch.backup_src_sz,
				sizeof(image->arch.backup_src_sz), 0);
		if (ret)
			return ret;
	}

	return ret;
}
216 217 218 219 220 221
#else /* !CONFIG_KEXEC_FILE */
static inline int arch_update_purgatory(struct kimage *image)
{
	return 0;
}
#endif /* CONFIG_KEXEC_FILE */
222

223 224
int machine_kexec_prepare(struct kimage *image)
{
225
	unsigned long start_pgtable;
226 227 228
	int result;

	/* Calculate the offsets */
Maneesh Soni's avatar
Maneesh Soni committed
229
	start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
230 231 232

	/* Setup the identity mapped 64bit page table */
	result = init_pgtable(image, start_pgtable);
Maneesh Soni's avatar
Maneesh Soni committed
233
	if (result)
234 235
		return result;

236 237 238 239 240
	/* update purgatory as needed */
	result = arch_update_purgatory(image);
	if (result)
		return result;

241 242 243 244 245
	return 0;
}

void machine_kexec_cleanup(struct kimage *image)
{
246
	free_transition_pgtable(image);
247 248 249 250 251 252
}

/*
 * Do not allocate memory (or fail in any way) in machine_kexec().
 * We are past the point of no return, committed to rebooting now.
 */
Huang Ying's avatar
Huang Ying committed
253
void machine_kexec(struct kimage *image)
254
{
255 256
	unsigned long page_list[PAGES_NR];
	void *control_page;
257
	int save_ftrace_enabled;
258

259
#ifdef CONFIG_KEXEC_JUMP
260
	if (image->preserve_context)
261 262 263 264
		save_processor_state();
#endif

	save_ftrace_enabled = __ftrace_enabled_save();
Ingo Molnar's avatar
Ingo Molnar committed
265

266 267
	/* Interrupts aren't acceptable while we reboot */
	local_irq_disable();
268
	hw_breakpoint_disable();
269

270 271 272 273 274 275 276 277 278 279 280 281 282
	if (image->preserve_context) {
#ifdef CONFIG_X86_IO_APIC
		/*
		 * We need to put APICs in legacy mode so that we can
		 * get timer interrupts in second kernel. kexec/kdump
		 * paths already have calls to disable_IO_APIC() in
		 * one form or other. kexec jump path also need
		 * one.
		 */
		disable_IO_APIC();
#endif
	}

283
	control_page = page_address(image->control_code_page) + PAGE_SIZE;
284
	memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
285

286
	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
287
	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
288 289
	page_list[PA_TABLE_PAGE] =
	  (unsigned long)__pa(page_address(image->control_code_page));
290

291 292 293 294
	if (image->type == KEXEC_TYPE_DEFAULT)
		page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
						<< PAGE_SHIFT);

295 296
	/*
	 * The segment registers are funny things, they have both a
297 298 299 300
	 * visible and an invisible part.  Whenever the visible part is
	 * set to a specific selector, the invisible part is loaded
	 * with from a table in memory.  At no other time is the
	 * descriptor table in memory accessed.
301 302 303 304 305
	 *
	 * I take advantage of this here by force loading the
	 * segments, before I zap the gdt with an invalid value.
	 */
	load_segments();
306 307
	/*
	 * The gdt & idt are now invalid.
308 309
	 * If you want to load them you must set up your own idt & gdt.
	 */
310 311
	set_gdt(phys_to_virt(0), 0);
	set_idt(phys_to_virt(0), 0);
312

313
	/* now call it */
314 315 316 317 318 319
	image->start = relocate_kernel((unsigned long)image->head,
				       (unsigned long)page_list,
				       image->start,
				       image->preserve_context);

#ifdef CONFIG_KEXEC_JUMP
320
	if (image->preserve_context)
321 322 323 324
		restore_processor_state();
#endif

	__ftrace_enabled_restore(save_ftrace_enabled);
325
}
326

Ken'ichi Ohmichi's avatar
Ken'ichi Ohmichi committed
327 328
void arch_crash_save_vmcoreinfo(void)
{
329
	VMCOREINFO_SYMBOL(phys_base);
330
	VMCOREINFO_SYMBOL(init_level4_pgt);
331 332 333 334 335

#ifdef CONFIG_NUMA
	VMCOREINFO_SYMBOL(node_data);
	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
#endif
336 337
	vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
			      (unsigned long)&_text - __START_KERNEL);
Ken'ichi Ohmichi's avatar
Ken'ichi Ohmichi committed
338 339
}

340 341
/* arch-dependent functionality related to kexec file-based syscall */

342
#ifdef CONFIG_KEXEC_FILE
343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365
int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
				  unsigned long buf_len)
{
	int i, ret = -ENOEXEC;
	struct kexec_file_ops *fops;

	for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
		fops = kexec_file_loaders[i];
		if (!fops || !fops->probe)
			continue;

		ret = fops->probe(buf, buf_len);
		if (!ret) {
			image->fops = fops;
			return ret;
		}
	}

	return ret;
}

void *arch_kexec_kernel_image_load(struct kimage *image)
{
366 367 368
	vfree(image->arch.elf_headers);
	image->arch.elf_headers = NULL;

369 370 371 372 373 374 375 376 377 378 379 380 381 382
	if (!image->fops || !image->fops->load)
		return ERR_PTR(-ENOEXEC);

	return image->fops->load(image, image->kernel_buf,
				 image->kernel_buf_len, image->initrd_buf,
				 image->initrd_buf_len, image->cmdline_buf,
				 image->cmdline_buf_len);
}

int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
	if (!image->fops || !image->fops->cleanup)
		return 0;

383
	return image->fops->cleanup(image->image_loader_data);
384
}
385

386 387 388 389 390 391 392 393 394 395 396
int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel,
				 unsigned long kernel_len)
{
	if (!image->fops || !image->fops->verify_sig) {
		pr_debug("kernel loader does not support signature verification.");
		return -EKEYREJECTED;
	}

	return image->fops->verify_sig(kernel, kernel_len);
}

397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535
/*
 * Apply purgatory relocations.
 *
 * ehdr: Pointer to elf headers
 * sechdrs: Pointer to section headers.
 * relsec: section index of SHT_RELA section.
 *
 * TODO: Some of the code belongs to generic code. Move that in kexec.c.
 */
int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
				     Elf64_Shdr *sechdrs, unsigned int relsec)
{
	unsigned int i;
	Elf64_Rela *rel;
	Elf64_Sym *sym;
	void *location;
	Elf64_Shdr *section, *symtabsec;
	unsigned long address, sec_base, value;
	const char *strtab, *name, *shstrtab;

	/*
	 * ->sh_offset has been modified to keep the pointer to section
	 * contents in memory
	 */
	rel = (void *)sechdrs[relsec].sh_offset;

	/* Section to which relocations apply */
	section = &sechdrs[sechdrs[relsec].sh_info];

	pr_debug("Applying relocate section %u to %u\n", relsec,
		 sechdrs[relsec].sh_info);

	/* Associated symbol table */
	symtabsec = &sechdrs[sechdrs[relsec].sh_link];

	/* String table */
	if (symtabsec->sh_link >= ehdr->e_shnum) {
		/* Invalid strtab section number */
		pr_err("Invalid string table section index %d\n",
		       symtabsec->sh_link);
		return -ENOEXEC;
	}

	strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;

	/* section header string table */
	shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {

		/*
		 * rel[i].r_offset contains byte offset from beginning
		 * of section to the storage unit affected.
		 *
		 * This is location to update (->sh_offset). This is temporary
		 * buffer where section is currently loaded. This will finally
		 * be loaded to a different address later, pointed to by
		 * ->sh_addr. kexec takes care of moving it
		 *  (kexec_load_segment()).
		 */
		location = (void *)(section->sh_offset + rel[i].r_offset);

		/* Final address of the location */
		address = section->sh_addr + rel[i].r_offset;

		/*
		 * rel[i].r_info contains information about symbol table index
		 * w.r.t which relocation must be made and type of relocation
		 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
		 * these respectively.
		 */
		sym = (Elf64_Sym *)symtabsec->sh_offset +
				ELF64_R_SYM(rel[i].r_info);

		if (sym->st_name)
			name = strtab + sym->st_name;
		else
			name = shstrtab + sechdrs[sym->st_shndx].sh_name;

		pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
			 name, sym->st_info, sym->st_shndx, sym->st_value,
			 sym->st_size);

		if (sym->st_shndx == SHN_UNDEF) {
			pr_err("Undefined symbol: %s\n", name);
			return -ENOEXEC;
		}

		if (sym->st_shndx == SHN_COMMON) {
			pr_err("symbol '%s' in common section\n", name);
			return -ENOEXEC;
		}

		if (sym->st_shndx == SHN_ABS)
			sec_base = 0;
		else if (sym->st_shndx >= ehdr->e_shnum) {
			pr_err("Invalid section %d for symbol %s\n",
			       sym->st_shndx, name);
			return -ENOEXEC;
		} else
			sec_base = sechdrs[sym->st_shndx].sh_addr;

		value = sym->st_value;
		value += sec_base;
		value += rel[i].r_addend;

		switch (ELF64_R_TYPE(rel[i].r_info)) {
		case R_X86_64_NONE:
			break;
		case R_X86_64_64:
			*(u64 *)location = value;
			break;
		case R_X86_64_32:
			*(u32 *)location = value;
			if (value != *(u32 *)location)
				goto overflow;
			break;
		case R_X86_64_32S:
			*(s32 *)location = value;
			if ((s64)value != *(s32 *)location)
				goto overflow;
			break;
		case R_X86_64_PC32:
			value -= (u64)address;
			*(u32 *)location = value;
			break;
		default:
			pr_err("Unknown rela relocation: %llu\n",
			       ELF64_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;

overflow:
	pr_err("Overflow in relocation type %d value 0x%lx\n",
	       (int)ELF64_R_TYPE(rel[i].r_info), value);
	return -ENOEXEC;
}
536
#endif /* CONFIG_KEXEC_FILE */