main.c 20.0 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
/*
 *  linux/init/main.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  GK 2/5/95  -  Changed to support mounting root fs via NFS
 *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
 *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
 *  Simplified starting of init:  Michael A. Griffith <grif@acm.org> 
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
I
Ingo Molnar 已提交
17
#include <linux/stackprotector.h>
L
Linus Torvalds 已提交
18 19 20 21 22 23 24
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/bootmem.h>
25
#include <linux/acpi.h>
L
Linus Torvalds 已提交
26 27 28
#include <linux/tty.h>
#include <linux/percpu.h>
#include <linux/kmod.h>
N
Nick Piggin 已提交
29
#include <linux/vmalloc.h>
L
Linus Torvalds 已提交
30
#include <linux/kernel_stat.h>
31
#include <linux/start_kernel.h>
L
Linus Torvalds 已提交
32
#include <linux/security.h>
33
#include <linux/smp.h>
L
Linus Torvalds 已提交
34 35 36 37 38 39 40
#include <linux/profile.h>
#include <linux/rcupdate.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/writeback.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
41
#include <linux/cgroup.h>
L
Linus Torvalds 已提交
42
#include <linux/efi.h>
43
#include <linux/tick.h>
44
#include <linux/interrupt.h>
45
#include <linux/taskstats_kern.h>
46
#include <linux/delayacct.h>
L
Linus Torvalds 已提交
47 48 49 50
#include <linux/unistd.h>
#include <linux/rmap.h>
#include <linux/mempolicy.h>
#include <linux/key.h>
A
Adrian Bunk 已提交
51
#include <linux/buffer_head.h>
52
#include <linux/page_cgroup.h>
53
#include <linux/debug_locks.h>
54
#include <linux/debugobjects.h>
I
Ingo Molnar 已提交
55
#include <linux/lockdep.h>
C
Catalin Marinas 已提交
56
#include <linux/kmemleak.h>
57
#include <linux/pid_namespace.h>
58
#include <linux/device.h>
59
#include <linux/kthread.h>
60
#include <linux/sched.h>
61
#include <linux/signal.h>
62
#include <linux/idr.h>
63
#include <linux/kgdb.h>
64
#include <linux/ftrace.h>
65
#include <linux/async.h>
66
#include <linux/kmemcheck.h>
67
#include <linux/sfi.h>
68
#include <linux/shmem_fs.h>
69
#include <linux/slab.h>
70
#include <linux/perf_event.h>
L
Linus Torvalds 已提交
71 72 73 74

#include <asm/io.h>
#include <asm/bugs.h>
#include <asm/setup.h>
75
#include <asm/sections.h>
76
#include <asm/cacheflush.h>
L
Linus Torvalds 已提交
77 78 79 80 81

#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/smp.h>
#endif

82
static int kernel_init(void *);
L
Linus Torvalds 已提交
83 84 85 86 87 88 89 90

extern void init_IRQ(void);
extern void fork_init(unsigned long);
extern void mca_init(void);
extern void sbus_init(void);
extern void prio_tree_init(void);
extern void radix_tree_init(void);
extern void free_initmem(void);
91 92 93
#ifndef CONFIG_DEBUG_RODATA
static inline void mark_rodata_ro(void) { }
#endif
L
Linus Torvalds 已提交
94 95 96 97 98

#ifdef CONFIG_TC
extern void tc_init(void);
#endif

99 100 101 102 103 104 105 106 107
/*
 * Debug helper: via this flag we know that we are in 'early bootup code'
 * where only the boot processor is running with IRQ disabled.  This means
 * two things - IRQ must not be enabled before the flag is cleared and some
 * operations which are not allowed with IRQ disabled are allowed while the
 * flag is set.
 */
bool early_boot_irqs_disabled __read_mostly;

108
enum system_states system_state __read_mostly;
L
Linus Torvalds 已提交
109 110 111 112 113 114 115 116 117 118
EXPORT_SYMBOL(system_state);

/*
 * Boot command-line arguments
 */
#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT

extern void time_init(void);
/* Default late time init is NULL. archs can override this later. */
119
void (*__initdata late_time_init)(void);
L
Linus Torvalds 已提交
120 121
extern void softirq_init(void);

122 123 124 125 126 127
/* Untouched command line saved by arch-specific code. */
char __initdata boot_command_line[COMMAND_LINE_SIZE];
/* Untouched saved command line (eg. for /proc) */
char *saved_command_line;
/* Command line for parameter parsing */
static char *static_command_line;
L
Linus Torvalds 已提交
128 129

static char *execute_command;
130
static char *ramdisk_execute_command;
L
Linus Torvalds 已提交
131

J
Jan Beulich 已提交
132 133 134 135 136 137 138 139 140 141 142
/*
 * If set, this is an indication to the drivers that reset the underlying
 * device before going ahead with the initialization otherwise driver might
 * rely on the BIOS and skip the reset operation.
 *
 * This is useful if kernel is booting in an unreliable environment.
 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 * skipped and devices will be in unknown state.
 */
unsigned int reset_devices;
EXPORT_SYMBOL(reset_devices);
L
Linus Torvalds 已提交
143

144 145 146 147 148 149 150 151
static int __init set_reset_devices(char *str)
{
	reset_devices = 1;
	return 1;
}

__setup("reset_devices", set_reset_devices);

152 153
static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
L
Linus Torvalds 已提交
154 155
static const char *panic_later, *panic_param;

156
extern const struct obs_kernel_param __setup_start[], __setup_end[];
L
Linus Torvalds 已提交
157 158 159

static int __init obsolete_checksetup(char *line)
{
160
	const struct obs_kernel_param *p;
161
	int had_early_param = 0;
L
Linus Torvalds 已提交
162 163 164 165 166 167

	p = __setup_start;
	do {
		int n = strlen(p->str);
		if (!strncmp(line, p->str, n)) {
			if (p->early) {
168 169 170 171
				/* Already done in parse_early_param?
				 * (Needs exact match on param part).
				 * Keep iterating, as we can have early
				 * params and __setups of same names 8( */
L
Linus Torvalds 已提交
172
				if (line[n] == '\0' || line[n] == '=')
173
					had_early_param = 1;
L
Linus Torvalds 已提交
174 175 176 177 178 179 180 181 182
			} else if (!p->setup_func) {
				printk(KERN_WARNING "Parameter %s is obsolete,"
				       " ignored\n", p->str);
				return 1;
			} else if (p->setup_func(line + n))
				return 1;
		}
		p++;
	} while (p < __setup_end);
183 184

	return had_early_param;
L
Linus Torvalds 已提交
185 186 187 188 189 190 191 192 193 194 195 196 197
}

/*
 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 * still work even if initially too large, it will just take slightly longer
 */
unsigned long loops_per_jiffy = (1<<12);

EXPORT_SYMBOL(loops_per_jiffy);

static int __init debug_kernel(char *str)
{
	console_loglevel = 10;
198
	return 0;
L
Linus Torvalds 已提交
199 200 201 202 203
}

static int __init quiet_kernel(char *str)
{
	console_loglevel = 4;
204
	return 0;
L
Linus Torvalds 已提交
205 206
}

207 208
early_param("debug", debug_kernel);
early_param("quiet", quiet_kernel);
L
Linus Torvalds 已提交
209 210 211 212

static int __init loglevel(char *str)
{
	get_option(&str, &console_loglevel);
213
	return 0;
L
Linus Torvalds 已提交
214 215
}

216
early_param("loglevel", loglevel);
L
Linus Torvalds 已提交
217 218 219

/*
 * Unknown boot options get handed to init, unless they look like
220
 * unused parameters (modprobe will find them in /proc/cmdline).
L
Linus Torvalds 已提交
221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240
 */
static int __init unknown_bootoption(char *param, char *val)
{
	/* Change NUL term back to "=", to make "param" the whole string. */
	if (val) {
		/* param=val or param="val"? */
		if (val == param+strlen(param)+1)
			val[-1] = '=';
		else if (val == param+strlen(param)+2) {
			val[-2] = '=';
			memmove(val-1, val, strlen(val)+1);
			val--;
		} else
			BUG();
	}

	/* Handle obsolete-style parameters */
	if (obsolete_checksetup(param))
		return 0;

241 242
	/* Unused module parameter. */
	if (strchr(param, '.') && (!val || strchr(param, '.') < val))
L
Linus Torvalds 已提交
243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273
		return 0;

	if (panic_later)
		return 0;

	if (val) {
		/* Environment option */
		unsigned int i;
		for (i = 0; envp_init[i]; i++) {
			if (i == MAX_INIT_ENVS) {
				panic_later = "Too many boot env vars at `%s'";
				panic_param = param;
			}
			if (!strncmp(param, envp_init[i], val - param))
				break;
		}
		envp_init[i] = param;
	} else {
		/* Command line option */
		unsigned int i;
		for (i = 0; argv_init[i]; i++) {
			if (i == MAX_INIT_ARGS) {
				panic_later = "Too many boot init vars at `%s'";
				panic_param = param;
			}
		}
		argv_init[i] = param;
	}
	return 0;
}

274 275 276 277
#ifdef CONFIG_DEBUG_PAGEALLOC
int __read_mostly debug_pagealloc_enabled = 0;
#endif

L
Linus Torvalds 已提交
278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294
static int __init init_setup(char *str)
{
	unsigned int i;

	execute_command = str;
	/*
	 * In case LILO is going to boot us with default command line,
	 * it prepends "auto" before the whole cmdline which makes
	 * the shell think it should execute a script with such name.
	 * So we ignore all arguments entered _before_ init=... [MJ]
	 */
	for (i = 1; i < MAX_INIT_ARGS; i++)
		argv_init[i] = NULL;
	return 1;
}
__setup("init=", init_setup);

295 296 297 298 299 300 301 302 303 304 305 306
static int __init rdinit_setup(char *str)
{
	unsigned int i;

	ramdisk_execute_command = str;
	/* See "auto" comment in init_setup */
	for (i = 1; i < MAX_INIT_ARGS; i++)
		argv_init[i] = NULL;
	return 1;
}
__setup("rdinit=", rdinit_setup);

L
Linus Torvalds 已提交
307
#ifndef CONFIG_SMP
308
static const unsigned int setup_max_cpus = NR_CPUS;
L
Linus Torvalds 已提交
309 310 311 312 313 314 315 316 317
#ifdef CONFIG_X86_LOCAL_APIC
static void __init smp_init(void)
{
	APIC_init_uniprocessor();
}
#else
#define smp_init()	do { } while (0)
#endif

318
static inline void setup_nr_cpu_ids(void) { }
L
Linus Torvalds 已提交
319 320 321
static inline void smp_prepare_cpus(unsigned int maxcpus) { }
#endif

322 323 324 325 326 327 328 329 330 331 332 333 334 335
/*
 * We need to store the untouched command line for future reference.
 * We also need to store the touched command line since the parameter
 * parsing is performed in place, and we should allow a component to
 * store reference of name/value for future reference.
 */
static void __init setup_command_line(char *command_line)
{
	saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
	static_command_line = alloc_bootmem(strlen (command_line)+1);
	strcpy (saved_command_line, boot_command_line);
	strcpy (static_command_line, command_line);
}

L
Linus Torvalds 已提交
336 337 338 339 340 341 342 343 344
/*
 * We need to finalize in a non-__init function or else race conditions
 * between the root thread and the init thread may cause start_kernel to
 * be reaped by free_initmem before the root thread has proceeded to
 * cpu_idle.
 *
 * gcc-3.4 accidentally inlines this function, so use noinline.
 */

345 346
static __initdata DECLARE_COMPLETION(kthreadd_done);

347
static noinline void __init_refok rest_init(void)
L
Linus Torvalds 已提交
348
{
349 350
	int pid;

351
	rcu_scheduler_starting();
352
	/*
P
Peter Zijlstra 已提交
353
	 * We need to spawn init first so that it obtains pid 1, however
354 355 356
	 * the init task will end up wanting to create kthreads, which, if
	 * we schedule it before we create kthreadd, will OOPS.
	 */
357
	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
L
Linus Torvalds 已提交
358
	numa_default_policy();
359
	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
360
	rcu_read_lock();
P
Pavel Emelyanov 已提交
361
	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
362
	rcu_read_unlock();
363
	complete(&kthreadd_done);
364 365 366

	/*
	 * The boot idle thread must execute schedule()
I
Ingo Molnar 已提交
367
	 * at least once to get things moving:
368
	 */
I
Ingo Molnar 已提交
369
	init_idle_bootup_task(current);
370
	preempt_enable_no_resched();
371
	schedule();
372
	preempt_disable();
373

374
	/* Call into cpu_idle with preempt disabled */
L
Linus Torvalds 已提交
375
	cpu_idle();
I
Ingo Molnar 已提交
376
}
L
Linus Torvalds 已提交
377 378 379 380

/* Check for early params. */
static int __init do_early_param(char *param, char *val)
{
381
	const struct obs_kernel_param *p;
L
Linus Torvalds 已提交
382 383

	for (p = __setup_start; p < __setup_end; p++) {
384 385 386 387
		if ((p->early && strcmp(param, p->str) == 0) ||
		    (strcmp(param, "console") == 0 &&
		     strcmp(p->str, "earlycon") == 0)
		) {
L
Linus Torvalds 已提交
388 389 390 391 392 393 394 395 396
			if (p->setup_func(val) != 0)
				printk(KERN_WARNING
				       "Malformed early option '%s'\n", param);
		}
	}
	/* We accept everything at this stage. */
	return 0;
}

M
Magnus Damm 已提交
397 398 399 400 401
void __init parse_early_options(char *cmdline)
{
	parse_args("early options", cmdline, NULL, 0, do_early_param);
}

L
Linus Torvalds 已提交
402 403 404 405 406 407 408 409 410 411
/* Arch code calls this early on, or if not, just before other parsing. */
void __init parse_early_param(void)
{
	static __initdata int done = 0;
	static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];

	if (done)
		return;

	/* All fall through to do_early_param. */
412
	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
M
Magnus Damm 已提交
413
	parse_early_options(tmp_cmdline);
L
Linus Torvalds 已提交
414 415 416 417 418 419 420
	done = 1;
}

/*
 *	Activate the first processor.
 */

421 422 423 424
static void __init boot_cpu_init(void)
{
	int cpu = smp_processor_id();
	/* Mark the boot cpu "present", "online" etc for SMP and UP case */
425
	set_cpu_online(cpu, true);
426
	set_cpu_active(cpu, true);
427 428
	set_cpu_present(cpu, true);
	set_cpu_possible(cpu, true);
429 430
}

431
void __init __weak smp_setup_processor_id(void)
432 433 434
{
}

435 436 437 438
void __init __weak thread_info_cache_init(void)
{
}

P
Pekka Enberg 已提交
439 440 441 442 443
/*
 * Set up kernel memory allocators
 */
static void __init mm_init(void)
{
444 445 446 447 448
	/*
	 * page_cgroup requires countinous pages as memmap
	 * and it's bigger than MAX_ORDER unless SPARSEMEM.
	 */
	page_cgroup_init_flatmem();
P
Pekka Enberg 已提交
449 450
	mem_init();
	kmem_cache_init();
451
	percpu_init_late();
452
	pgtable_cache_init();
P
Pekka Enberg 已提交
453 454 455
	vmalloc_init();
}

L
Linus Torvalds 已提交
456 457 458
asmlinkage void __init start_kernel(void)
{
	char * command_line;
459
	extern const struct kernel_param __start___param[], __stop___param[];
460 461 462

	smp_setup_processor_id();

I
Ingo Molnar 已提交
463 464 465 466 467
	/*
	 * Need to run as early as possible, to initialize the
	 * lockdep hash:
	 */
	lockdep_init();
468
	debug_objects_early_init();
469 470 471 472 473 474

	/*
	 * Set up the the initial canary ASAP:
	 */
	boot_init_stack_canary();

475
	cgroup_init_early();
I
Ingo Molnar 已提交
476 477

	local_irq_disable();
478
	early_boot_irqs_disabled = true;
I
Ingo Molnar 已提交
479

L
Linus Torvalds 已提交
480 481 482 483
/*
 * Interrupts are still disabled. Do necessary setups, then
 * enable them
 */
484
	tick_init();
485
	boot_cpu_init();
L
Linus Torvalds 已提交
486
	page_address_init();
A
Alex Riesen 已提交
487
	printk(KERN_NOTICE "%s", linux_banner);
L
Linus Torvalds 已提交
488
	setup_arch(&command_line);
489
	mm_init_owner(&init_mm, &init_task);
490
	setup_command_line(command_line);
491
	setup_nr_cpu_ids();
492
	setup_per_cpu_areas();
493
	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
L
Linus Torvalds 已提交
494

495
	build_all_zonelists(NULL);
496 497 498 499 500 501 502 503 504 505 506 507 508 509 510
	page_alloc_init();

	printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
	parse_early_param();
	parse_args("Booting kernel", static_command_line, __start___param,
		   __stop___param - __start___param,
		   &unknown_bootoption);
	/*
	 * These use large bootmem allocations and must precede
	 * kmem_cache_init()
	 */
	pidhash_init();
	vfs_caches_init_early();
	sort_main_extable();
	trap_init();
P
Pekka Enberg 已提交
511
	mm_init();
512 513
	BUG_ON(mm_init_cpumask(&init_mm, 0));

L
Linus Torvalds 已提交
514 515 516 517 518 519 520 521 522 523 524
	/*
	 * Set up the scheduler prior starting any interrupts (such as the
	 * timer interrupt). Full topology setup happens at smp_init()
	 * time - but meanwhile we still have a functioning scheduler.
	 */
	sched_init();
	/*
	 * Disable preemption - early bootup scheduling is extremely
	 * fragile until we cpu_idle() for the first time.
	 */
	preempt_disable();
525 526 527 528 529
	if (!irqs_disabled()) {
		printk(KERN_WARNING "start_kernel(): bug: interrupts were "
				"enabled *very* early, fixing it\n");
		local_irq_disable();
	}
P
Peter Zijlstra 已提交
530
	idr_init_cache();
531
	perf_event_init();
L
Linus Torvalds 已提交
532
	rcu_init();
Y
Yinghai Lu 已提交
533
	radix_tree_init();
534 535
	/* init some links before init_ISA_irqs() */
	early_irq_init();
L
Linus Torvalds 已提交
536
	init_IRQ();
C
Catalin Marinas 已提交
537
	prio_tree_init();
L
Linus Torvalds 已提交
538
	init_timers();
539
	hrtimers_init();
L
Linus Torvalds 已提交
540
	softirq_init();
541
	timekeeping_init();
J
john stultz 已提交
542
	time_init();
543 544
	profile_init();
	if (!irqs_disabled())
545 546
		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
				 "enabled early\n");
547
	early_boot_irqs_disabled = false;
548
	local_irq_enable();
549 550

	/* Interrupts are enabled now so all GFP allocations are safe. */
551
	gfp_allowed_mask = __GFP_BITS_MASK;
552

553
	kmem_cache_init_late();
L
Linus Torvalds 已提交
554 555 556 557 558 559 560 561 562

	/*
	 * HACK ALERT! This is early. We're enabling the console before
	 * we've done PCI setups etc, and console_init() must be aware of
	 * this. But we do want output early, in case something goes wrong.
	 */
	console_init();
	if (panic_later)
		panic(panic_later, panic_param);
I
Ingo Molnar 已提交
563 564 565

	lockdep_info();

566 567 568 569 570 571 572
	/*
	 * Need to run this when irqs are enabled, because it wants
	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
	 * too:
	 */
	locking_selftest();

L
Linus Torvalds 已提交
573 574
#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start && !initrd_below_start_ok &&
575
	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
L
Linus Torvalds 已提交
576
		printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
577
		    "disabling it.\n",
578 579
		    page_to_pfn(virt_to_page((void *)initrd_start)),
		    min_low_pfn);
L
Linus Torvalds 已提交
580 581 582
		initrd_start = 0;
	}
#endif
583
	page_cgroup_init();
584
	enable_debug_pagealloc();
585
	debug_objects_mem_init();
586
	kmemleak_init();
587
	setup_per_cpu_pageset();
L
Linus Torvalds 已提交
588 589 590
	numa_policy_init();
	if (late_time_init)
		late_time_init();
591
	sched_clock_init();
L
Linus Torvalds 已提交
592 593 594 595 596 597 598
	calibrate_delay();
	pidmap_init();
	anon_vma_init();
#ifdef CONFIG_X86
	if (efi_enabled)
		efi_enter_virtual_mode();
#endif
599
	thread_info_cache_init();
D
David Howells 已提交
600
	cred_init();
601
	fork_init(totalram_pages);
L
Linus Torvalds 已提交
602 603 604 605
	proc_caches_init();
	buffer_init();
	key_init();
	security_init();
606
	dbg_late_init();
607
	vfs_caches_init(totalram_pages);
L
Linus Torvalds 已提交
608 609 610 611 612 613
	signals_init();
	/* rootfs populating might need page-writeback */
	page_writeback_init();
#ifdef CONFIG_PROC_FS
	proc_root_init();
#endif
614
	cgroup_init();
L
Linus Torvalds 已提交
615
	cpuset_init();
616
	taskstats_init_early();
617
	delayacct_init();
L
Linus Torvalds 已提交
618 619 620 621

	check_bugs();

	acpi_early_init(); /* before LAPIC and SMP init */
622
	sfi_init_late();
L
Linus Torvalds 已提交
623

624 625
	ftrace_init();

L
Linus Torvalds 已提交
626 627 628 629
	/* Do the rest non-__init'ed, we're now alive */
	rest_init();
}

630 631 632 633
/* Call all constructor functions linked into the kernel. */
static void __init do_ctors(void)
{
#ifdef CONFIG_CONSTRUCTORS
634
	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
635

636 637
	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
		(*fn)();
638 639 640
#endif
}

641
int initcall_debug;
R
Rusty Russell 已提交
642
core_param(initcall_debug, initcall_debug, bool, 0644);
L
Linus Torvalds 已提交
643

644 645
static char msgbuf[64];

646
static int __init_or_module do_one_initcall_debug(initcall_t fn)
L
Linus Torvalds 已提交
647
{
648
	ktime_t calltime, delta, rettime;
A
Américo Wang 已提交
649 650
	unsigned long long duration;
	int ret;
L
Linus Torvalds 已提交
651

652 653
	printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
	calltime = ktime_get();
A
Américo Wang 已提交
654
	ret = fn();
655 656 657 658 659
	rettime = ktime_get();
	delta = ktime_sub(rettime, calltime);
	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
	printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
		ret, duration);
L
Linus Torvalds 已提交
660

661 662 663
	return ret;
}

664
int __init_or_module do_one_initcall(initcall_t fn)
665 666 667 668 669 670 671 672
{
	int count = preempt_count();
	int ret;

	if (initcall_debug)
		ret = do_one_initcall_debug(fn);
	else
		ret = fn();
673

674
	msgbuf[0] = 0;
675

A
Américo Wang 已提交
676 677
	if (ret && ret != -ENODEV && initcall_debug)
		sprintf(msgbuf, "error code %d ", ret);
678

679
	if (preempt_count() != count) {
680
		strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
681
		preempt_count() = count;
L
Linus Torvalds 已提交
682
	}
683
	if (irqs_disabled()) {
684
		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
685 686 687
		local_irq_enable();
	}
	if (msgbuf[0]) {
688
		printk("initcall %pF returned with %s\n", fn, msgbuf);
689
	}
690

A
Américo Wang 已提交
691
	return ret;
692 693 694
}


695
extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
696 697 698

static void __init do_initcalls(void)
{
699
	initcall_t *fn;
700

701 702
	for (fn = __early_initcall_end; fn < __initcall_end; fn++)
		do_one_initcall(*fn);
L
Linus Torvalds 已提交
703 704 705 706 707 708 709 710 711 712 713
}

/*
 * Ok, the machine is now initialized. None of the devices
 * have been touched yet, but the CPU subsystem is up and
 * running, and memory and process management works.
 *
 * Now we can finally start doing some real work..
 */
static void __init do_basic_setup(void)
{
714
	cpuset_init_smp();
L
Linus Torvalds 已提交
715
	usermodehelper_init();
716
	init_tmpfs();
L
Linus Torvalds 已提交
717
	driver_init();
718
	init_irq_proc();
719
	do_ctors();
L
Linus Torvalds 已提交
720 721 722
	do_initcalls();
}

723
static void __init do_pre_smp_initcalls(void)
724
{
725
	initcall_t *fn;
726

727 728
	for (fn = __initcall_start; fn < __early_initcall_end; fn++)
		do_one_initcall(*fn);
729 730
}

731
static void run_init_process(const char *init_filename)
L
Linus Torvalds 已提交
732 733
{
	argv_init[0] = init_filename;
A
Arnd Bergmann 已提交
734
	kernel_execve(init_filename, argv_init, envp_init);
L
Linus Torvalds 已提交
735 736
}

737 738 739
/* This is a non __init function. Force it to be noinline otherwise gcc
 * makes it inline to init() and it becomes part of init.text section
 */
740
static noinline int init_post(void)
741
{
742 743
	/* need to finish all async __init code before freeing the memory */
	async_synchronize_full();
744 745 746 747 748 749
	free_initmem();
	mark_rodata_ro();
	system_state = SYSTEM_RUNNING;
	numa_default_policy();


750 751
	current->signal->flags |= SIGNAL_UNKILLABLE;

752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773
	if (ramdisk_execute_command) {
		run_init_process(ramdisk_execute_command);
		printk(KERN_WARNING "Failed to execute %s\n",
				ramdisk_execute_command);
	}

	/*
	 * We try each of these until one succeeds.
	 *
	 * The Bourne shell can be used instead of init if we are
	 * trying to recover a really broken machine.
	 */
	if (execute_command) {
		run_init_process(execute_command);
		printk(KERN_WARNING "Failed to execute %s.  Attempting "
					"defaults...\n", execute_command);
	}
	run_init_process("/sbin/init");
	run_init_process("/etc/init");
	run_init_process("/bin/init");
	run_init_process("/bin/sh");

774 775
	panic("No init found.  Try passing init= option to kernel. "
	      "See Linux Documentation/init.txt for guidance.");
776 777
}

778
static int __init kernel_init(void * unused)
L
Linus Torvalds 已提交
779
{
780 781 782 783
	/*
	 * Wait until kthreadd is all set-up.
	 */
	wait_for_completion(&kthreadd_done);
784 785 786
	/*
	 * init can allocate pages on any node
	 */
787
	set_mems_allowed(node_states[N_HIGH_MEMORY]);
L
Linus Torvalds 已提交
788 789 790
	/*
	 * init can run on any cpu.
	 */
791
	set_cpus_allowed_ptr(current, cpu_all_mask);
L
Linus Torvalds 已提交
792

793 794
	cad_pid = task_pid(current);

795
	smp_prepare_cpus(setup_max_cpus);
L
Linus Torvalds 已提交
796 797

	do_pre_smp_initcalls();
798
	lockup_detector_init();
L
Linus Torvalds 已提交
799 800 801 802 803 804

	smp_init();
	sched_init_smp();

	do_basic_setup();

805 806 807 808 809 810
	/* Open the /dev/console on the rootfs, this should never fail */
	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
		printk(KERN_WARNING "Warning: unable to open an initial console.\n");

	(void) sys_dup(0);
	(void) sys_dup(0);
L
Linus Torvalds 已提交
811 812 813 814
	/*
	 * check if there is an early userspace init.  If yes, let it do all
	 * the work
	 */
815 816 817 818 819 820

	if (!ramdisk_execute_command)
		ramdisk_execute_command = "/init";

	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
		ramdisk_execute_command = NULL;
L
Linus Torvalds 已提交
821
		prepare_namespace();
822
	}
L
Linus Torvalds 已提交
823 824 825 826 827 828

	/*
	 * Ok, we have completed the initial bootup, and
	 * we're essentially up and running. Get rid of the
	 * initmem segments and start the user-mode stuff..
	 */
829

830 831
	init_post();
	return 0;
L
Linus Torvalds 已提交
832
}