xref: /openbmc/linux/init/main.c (revision fd589a8f)
1 /*
2  *  linux/init/main.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  *
6  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
7  *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
8  *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
9  *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
10  */
11 
12 #include <linux/types.h>
13 #include <linux/module.h>
14 #include <linux/proc_fs.h>
15 #include <linux/kernel.h>
16 #include <linux/syscalls.h>
17 #include <linux/stackprotector.h>
18 #include <linux/string.h>
19 #include <linux/ctype.h>
20 #include <linux/delay.h>
21 #include <linux/utsname.h>
22 #include <linux/ioport.h>
23 #include <linux/init.h>
24 #include <linux/smp_lock.h>
25 #include <linux/initrd.h>
26 #include <linux/bootmem.h>
27 #include <linux/acpi.h>
28 #include <linux/tty.h>
29 #include <linux/gfp.h>
30 #include <linux/percpu.h>
31 #include <linux/kmod.h>
32 #include <linux/vmalloc.h>
33 #include <linux/kernel_stat.h>
34 #include <linux/start_kernel.h>
35 #include <linux/security.h>
36 #include <linux/smp.h>
37 #include <linux/workqueue.h>
38 #include <linux/profile.h>
39 #include <linux/rcupdate.h>
40 #include <linux/moduleparam.h>
41 #include <linux/kallsyms.h>
42 #include <linux/writeback.h>
43 #include <linux/cpu.h>
44 #include <linux/cpuset.h>
45 #include <linux/cgroup.h>
46 #include <linux/efi.h>
47 #include <linux/tick.h>
48 #include <linux/interrupt.h>
49 #include <linux/taskstats_kern.h>
50 #include <linux/delayacct.h>
51 #include <linux/unistd.h>
52 #include <linux/rmap.h>
53 #include <linux/mempolicy.h>
54 #include <linux/key.h>
55 #include <linux/buffer_head.h>
56 #include <linux/page_cgroup.h>
57 #include <linux/debug_locks.h>
58 #include <linux/debugobjects.h>
59 #include <linux/lockdep.h>
60 #include <linux/kmemleak.h>
61 #include <linux/pid_namespace.h>
62 #include <linux/device.h>
63 #include <linux/kthread.h>
64 #include <linux/sched.h>
65 #include <linux/signal.h>
66 #include <linux/idr.h>
67 #include <linux/ftrace.h>
68 #include <linux/async.h>
69 #include <linux/kmemcheck.h>
70 #include <linux/kmemtrace.h>
71 #include <linux/shmem_fs.h>
72 #include <trace/boot.h>
73 
74 #include <asm/io.h>
75 #include <asm/bugs.h>
76 #include <asm/setup.h>
77 #include <asm/sections.h>
78 #include <asm/cacheflush.h>
79 
80 #ifdef CONFIG_X86_LOCAL_APIC
81 #include <asm/smp.h>
82 #endif
83 
84 static int kernel_init(void *);
85 
86 extern void init_IRQ(void);
87 extern void fork_init(unsigned long);
88 extern void mca_init(void);
89 extern void sbus_init(void);
90 extern void prio_tree_init(void);
91 extern void radix_tree_init(void);
92 extern void free_initmem(void);
93 #ifndef CONFIG_DEBUG_RODATA
94 static inline void mark_rodata_ro(void) { }
95 #endif
96 
97 #ifdef CONFIG_TC
98 extern void tc_init(void);
99 #endif
100 
101 enum system_states system_state __read_mostly;
102 EXPORT_SYMBOL(system_state);
103 
104 /*
105  * Boot command-line arguments
106  */
107 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
108 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
109 
110 extern void time_init(void);
111 /* Default late time init is NULL. archs can override this later. */
112 void (*__initdata late_time_init)(void);
113 extern void softirq_init(void);
114 
115 /* Untouched command line saved by arch-specific code. */
116 char __initdata boot_command_line[COMMAND_LINE_SIZE];
117 /* Untouched saved command line (eg. for /proc) */
118 char *saved_command_line;
119 /* Command line for parameter parsing */
120 static char *static_command_line;
121 
122 static char *execute_command;
123 static char *ramdisk_execute_command;
124 
125 #ifdef CONFIG_SMP
126 /* Setup configured maximum number of CPUs to activate */
127 unsigned int __initdata setup_max_cpus = NR_CPUS;
128 
129 /*
130  * Setup routine for controlling SMP activation
131  *
132  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
133  * activation entirely (the MPS table probe still happens, though).
134  *
135  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
136  * greater than 0, limits the maximum number of CPUs activated in
137  * SMP mode to <NUM>.
138  */
139 
140 void __weak arch_disable_smp_support(void) { }
141 
142 static int __init nosmp(char *str)
143 {
144 	setup_max_cpus = 0;
145 	arch_disable_smp_support();
146 
147 	return 0;
148 }
149 
150 early_param("nosmp", nosmp);
151 
152 static int __init maxcpus(char *str)
153 {
154 	get_option(&str, &setup_max_cpus);
155 	if (setup_max_cpus == 0)
156 		arch_disable_smp_support();
157 
158 	return 0;
159 }
160 
161 early_param("maxcpus", maxcpus);
162 #else
163 const unsigned int setup_max_cpus = NR_CPUS;
164 #endif
165 
166 /*
167  * If set, this is an indication to the drivers that reset the underlying
168  * device before going ahead with the initialization otherwise driver might
169  * rely on the BIOS and skip the reset operation.
170  *
171  * This is useful if kernel is booting in an unreliable environment.
172  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
173  * skipped and devices will be in unknown state.
174  */
175 unsigned int reset_devices;
176 EXPORT_SYMBOL(reset_devices);
177 
178 static int __init set_reset_devices(char *str)
179 {
180 	reset_devices = 1;
181 	return 1;
182 }
183 
184 __setup("reset_devices", set_reset_devices);
185 
186 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
187 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
188 static const char *panic_later, *panic_param;
189 
190 extern struct obs_kernel_param __setup_start[], __setup_end[];
191 
192 static int __init obsolete_checksetup(char *line)
193 {
194 	struct obs_kernel_param *p;
195 	int had_early_param = 0;
196 
197 	p = __setup_start;
198 	do {
199 		int n = strlen(p->str);
200 		if (!strncmp(line, p->str, n)) {
201 			if (p->early) {
202 				/* Already done in parse_early_param?
203 				 * (Needs exact match on param part).
204 				 * Keep iterating, as we can have early
205 				 * params and __setups of same names 8( */
206 				if (line[n] == '\0' || line[n] == '=')
207 					had_early_param = 1;
208 			} else if (!p->setup_func) {
209 				printk(KERN_WARNING "Parameter %s is obsolete,"
210 				       " ignored\n", p->str);
211 				return 1;
212 			} else if (p->setup_func(line + n))
213 				return 1;
214 		}
215 		p++;
216 	} while (p < __setup_end);
217 
218 	return had_early_param;
219 }
220 
221 /*
222  * This should be approx 2 Bo*oMips to start (note initial shift), and will
223  * still work even if initially too large, it will just take slightly longer
224  */
225 unsigned long loops_per_jiffy = (1<<12);
226 
227 EXPORT_SYMBOL(loops_per_jiffy);
228 
229 static int __init debug_kernel(char *str)
230 {
231 	console_loglevel = 10;
232 	return 0;
233 }
234 
235 static int __init quiet_kernel(char *str)
236 {
237 	console_loglevel = 4;
238 	return 0;
239 }
240 
241 early_param("debug", debug_kernel);
242 early_param("quiet", quiet_kernel);
243 
244 static int __init loglevel(char *str)
245 {
246 	get_option(&str, &console_loglevel);
247 	return 0;
248 }
249 
250 early_param("loglevel", loglevel);
251 
252 /*
253  * Unknown boot options get handed to init, unless they look like
254  * failed parameters
255  */
256 static int __init unknown_bootoption(char *param, char *val)
257 {
258 	/* Change NUL term back to "=", to make "param" the whole string. */
259 	if (val) {
260 		/* param=val or param="val"? */
261 		if (val == param+strlen(param)+1)
262 			val[-1] = '=';
263 		else if (val == param+strlen(param)+2) {
264 			val[-2] = '=';
265 			memmove(val-1, val, strlen(val)+1);
266 			val--;
267 		} else
268 			BUG();
269 	}
270 
271 	/* Handle obsolete-style parameters */
272 	if (obsolete_checksetup(param))
273 		return 0;
274 
275 	/*
276 	 * Preemptive maintenance for "why didn't my misspelled command
277 	 * line work?"
278 	 */
279 	if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
280 		printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
281 		return 0;
282 	}
283 
284 	if (panic_later)
285 		return 0;
286 
287 	if (val) {
288 		/* Environment option */
289 		unsigned int i;
290 		for (i = 0; envp_init[i]; i++) {
291 			if (i == MAX_INIT_ENVS) {
292 				panic_later = "Too many boot env vars at `%s'";
293 				panic_param = param;
294 			}
295 			if (!strncmp(param, envp_init[i], val - param))
296 				break;
297 		}
298 		envp_init[i] = param;
299 	} else {
300 		/* Command line option */
301 		unsigned int i;
302 		for (i = 0; argv_init[i]; i++) {
303 			if (i == MAX_INIT_ARGS) {
304 				panic_later = "Too many boot init vars at `%s'";
305 				panic_param = param;
306 			}
307 		}
308 		argv_init[i] = param;
309 	}
310 	return 0;
311 }
312 
313 #ifdef CONFIG_DEBUG_PAGEALLOC
314 int __read_mostly debug_pagealloc_enabled = 0;
315 #endif
316 
317 static int __init init_setup(char *str)
318 {
319 	unsigned int i;
320 
321 	execute_command = str;
322 	/*
323 	 * In case LILO is going to boot us with default command line,
324 	 * it prepends "auto" before the whole cmdline which makes
325 	 * the shell think it should execute a script with such name.
326 	 * So we ignore all arguments entered _before_ init=... [MJ]
327 	 */
328 	for (i = 1; i < MAX_INIT_ARGS; i++)
329 		argv_init[i] = NULL;
330 	return 1;
331 }
332 __setup("init=", init_setup);
333 
334 static int __init rdinit_setup(char *str)
335 {
336 	unsigned int i;
337 
338 	ramdisk_execute_command = str;
339 	/* See "auto" comment in init_setup */
340 	for (i = 1; i < MAX_INIT_ARGS; i++)
341 		argv_init[i] = NULL;
342 	return 1;
343 }
344 __setup("rdinit=", rdinit_setup);
345 
346 #ifndef CONFIG_SMP
347 
348 #ifdef CONFIG_X86_LOCAL_APIC
349 static void __init smp_init(void)
350 {
351 	APIC_init_uniprocessor();
352 }
353 #else
354 #define smp_init()	do { } while (0)
355 #endif
356 
357 static inline void setup_nr_cpu_ids(void) { }
358 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
359 
360 #else
361 
362 #if NR_CPUS > BITS_PER_LONG
363 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
364 EXPORT_SYMBOL(cpu_mask_all);
365 #endif
366 
367 /* Setup number of possible processor ids */
368 int nr_cpu_ids __read_mostly = NR_CPUS;
369 EXPORT_SYMBOL(nr_cpu_ids);
370 
371 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
372 static void __init setup_nr_cpu_ids(void)
373 {
374 	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
375 }
376 
377 /* Called by boot processor to activate the rest. */
378 static void __init smp_init(void)
379 {
380 	unsigned int cpu;
381 
382 	/*
383 	 * Set up the current CPU as possible to migrate to.
384 	 * The other ones will be done by cpu_up/cpu_down()
385 	 */
386 	set_cpu_active(smp_processor_id(), true);
387 
388 	/* FIXME: This should be done in userspace --RR */
389 	for_each_present_cpu(cpu) {
390 		if (num_online_cpus() >= setup_max_cpus)
391 			break;
392 		if (!cpu_online(cpu))
393 			cpu_up(cpu);
394 	}
395 
396 	/* Any cleanup work */
397 	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
398 	smp_cpus_done(setup_max_cpus);
399 }
400 
401 #endif
402 
403 /*
404  * We need to store the untouched command line for future reference.
405  * We also need to store the touched command line since the parameter
406  * parsing is performed in place, and we should allow a component to
407  * store reference of name/value for future reference.
408  */
409 static void __init setup_command_line(char *command_line)
410 {
411 	saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
412 	static_command_line = alloc_bootmem(strlen (command_line)+1);
413 	strcpy (saved_command_line, boot_command_line);
414 	strcpy (static_command_line, command_line);
415 }
416 
417 /*
418  * We need to finalize in a non-__init function or else race conditions
419  * between the root thread and the init thread may cause start_kernel to
420  * be reaped by free_initmem before the root thread has proceeded to
421  * cpu_idle.
422  *
423  * gcc-3.4 accidentally inlines this function, so use noinline.
424  */
425 
426 static noinline void __init_refok rest_init(void)
427 	__releases(kernel_lock)
428 {
429 	int pid;
430 
431 	rcu_scheduler_starting();
432 	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
433 	numa_default_policy();
434 	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
435 	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
436 	unlock_kernel();
437 
438 	/*
439 	 * The boot idle thread must execute schedule()
440 	 * at least once to get things moving:
441 	 */
442 	init_idle_bootup_task(current);
443 	preempt_enable_no_resched();
444 	schedule();
445 	preempt_disable();
446 
447 	/* Call into cpu_idle with preempt disabled */
448 	cpu_idle();
449 }
450 
451 /* Check for early params. */
452 static int __init do_early_param(char *param, char *val)
453 {
454 	struct obs_kernel_param *p;
455 
456 	for (p = __setup_start; p < __setup_end; p++) {
457 		if ((p->early && strcmp(param, p->str) == 0) ||
458 		    (strcmp(param, "console") == 0 &&
459 		     strcmp(p->str, "earlycon") == 0)
460 		) {
461 			if (p->setup_func(val) != 0)
462 				printk(KERN_WARNING
463 				       "Malformed early option '%s'\n", param);
464 		}
465 	}
466 	/* We accept everything at this stage. */
467 	return 0;
468 }
469 
470 void __init parse_early_options(char *cmdline)
471 {
472 	parse_args("early options", cmdline, NULL, 0, do_early_param);
473 }
474 
475 /* Arch code calls this early on, or if not, just before other parsing. */
476 void __init parse_early_param(void)
477 {
478 	static __initdata int done = 0;
479 	static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
480 
481 	if (done)
482 		return;
483 
484 	/* All fall through to do_early_param. */
485 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
486 	parse_early_options(tmp_cmdline);
487 	done = 1;
488 }
489 
490 /*
491  *	Activate the first processor.
492  */
493 
494 static void __init boot_cpu_init(void)
495 {
496 	int cpu = smp_processor_id();
497 	/* Mark the boot cpu "present", "online" etc for SMP and UP case */
498 	set_cpu_online(cpu, true);
499 	set_cpu_present(cpu, true);
500 	set_cpu_possible(cpu, true);
501 }
502 
503 void __init __weak smp_setup_processor_id(void)
504 {
505 }
506 
507 void __init __weak thread_info_cache_init(void)
508 {
509 }
510 
511 /*
512  * Set up kernel memory allocators
513  */
514 static void __init mm_init(void)
515 {
516 	/*
517 	 * page_cgroup requires countinous pages as memmap
518 	 * and it's bigger than MAX_ORDER unless SPARSEMEM.
519 	 */
520 	page_cgroup_init_flatmem();
521 	mem_init();
522 	kmem_cache_init();
523 	pgtable_cache_init();
524 	vmalloc_init();
525 }
526 
527 asmlinkage void __init start_kernel(void)
528 {
529 	char * command_line;
530 	extern struct kernel_param __start___param[], __stop___param[];
531 
532 	smp_setup_processor_id();
533 
534 	/*
535 	 * Need to run as early as possible, to initialize the
536 	 * lockdep hash:
537 	 */
538 	lockdep_init();
539 	debug_objects_early_init();
540 
541 	/*
542 	 * Set up the the initial canary ASAP:
543 	 */
544 	boot_init_stack_canary();
545 
546 	cgroup_init_early();
547 
548 	local_irq_disable();
549 	early_boot_irqs_off();
550 	early_init_irq_lock_class();
551 
552 /*
553  * Interrupts are still disabled. Do necessary setups, then
554  * enable them
555  */
556 	lock_kernel();
557 	tick_init();
558 	boot_cpu_init();
559 	page_address_init();
560 	printk(KERN_NOTICE "%s", linux_banner);
561 	setup_arch(&command_line);
562 	mm_init_owner(&init_mm, &init_task);
563 	setup_command_line(command_line);
564 	setup_nr_cpu_ids();
565 	setup_per_cpu_areas();
566 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
567 
568 	build_all_zonelists();
569 	page_alloc_init();
570 
571 	printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
572 	parse_early_param();
573 	parse_args("Booting kernel", static_command_line, __start___param,
574 		   __stop___param - __start___param,
575 		   &unknown_bootoption);
576 	/*
577 	 * These use large bootmem allocations and must precede
578 	 * kmem_cache_init()
579 	 */
580 	pidhash_init();
581 	vfs_caches_init_early();
582 	sort_main_extable();
583 	trap_init();
584 	mm_init();
585 	/*
586 	 * Set up the scheduler prior starting any interrupts (such as the
587 	 * timer interrupt). Full topology setup happens at smp_init()
588 	 * time - but meanwhile we still have a functioning scheduler.
589 	 */
590 	sched_init();
591 	/*
592 	 * Disable preemption - early bootup scheduling is extremely
593 	 * fragile until we cpu_idle() for the first time.
594 	 */
595 	preempt_disable();
596 	if (!irqs_disabled()) {
597 		printk(KERN_WARNING "start_kernel(): bug: interrupts were "
598 				"enabled *very* early, fixing it\n");
599 		local_irq_disable();
600 	}
601 	rcu_init();
602 	/* init some links before init_ISA_irqs() */
603 	early_irq_init();
604 	init_IRQ();
605 	prio_tree_init();
606 	init_timers();
607 	hrtimers_init();
608 	softirq_init();
609 	timekeeping_init();
610 	time_init();
611 	profile_init();
612 	if (!irqs_disabled())
613 		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
614 				 "enabled early\n");
615 	early_boot_irqs_on();
616 	local_irq_enable();
617 
618 	/* Interrupts are enabled now so all GFP allocations are safe. */
619 	set_gfp_allowed_mask(__GFP_BITS_MASK);
620 
621 	kmem_cache_init_late();
622 
623 	/*
624 	 * HACK ALERT! This is early. We're enabling the console before
625 	 * we've done PCI setups etc, and console_init() must be aware of
626 	 * this. But we do want output early, in case something goes wrong.
627 	 */
628 	console_init();
629 	if (panic_later)
630 		panic(panic_later, panic_param);
631 
632 	lockdep_info();
633 
634 	/*
635 	 * Need to run this when irqs are enabled, because it wants
636 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
637 	 * too:
638 	 */
639 	locking_selftest();
640 
641 #ifdef CONFIG_BLK_DEV_INITRD
642 	if (initrd_start && !initrd_below_start_ok &&
643 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
644 		printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
645 		    "disabling it.\n",
646 		    page_to_pfn(virt_to_page((void *)initrd_start)),
647 		    min_low_pfn);
648 		initrd_start = 0;
649 	}
650 #endif
651 	page_cgroup_init();
652 	enable_debug_pagealloc();
653 	kmemtrace_init();
654 	kmemleak_init();
655 	debug_objects_mem_init();
656 	idr_init_cache();
657 	setup_per_cpu_pageset();
658 	numa_policy_init();
659 	if (late_time_init)
660 		late_time_init();
661 	sched_clock_init();
662 	calibrate_delay();
663 	pidmap_init();
664 	anon_vma_init();
665 #ifdef CONFIG_X86
666 	if (efi_enabled)
667 		efi_enter_virtual_mode();
668 #endif
669 	thread_info_cache_init();
670 	cred_init();
671 	fork_init(num_physpages);
672 	proc_caches_init();
673 	buffer_init();
674 	key_init();
675 	security_init();
676 	vfs_caches_init(num_physpages);
677 	radix_tree_init();
678 	signals_init();
679 	/* rootfs populating might need page-writeback */
680 	page_writeback_init();
681 #ifdef CONFIG_PROC_FS
682 	proc_root_init();
683 #endif
684 	cgroup_init();
685 	cpuset_init();
686 	taskstats_init_early();
687 	delayacct_init();
688 
689 	check_bugs();
690 
691 	acpi_early_init(); /* before LAPIC and SMP init */
692 
693 	ftrace_init();
694 
695 	/* Do the rest non-__init'ed, we're now alive */
696 	rest_init();
697 }
698 
699 /* Call all constructor functions linked into the kernel. */
700 static void __init do_ctors(void)
701 {
702 #ifdef CONFIG_CONSTRUCTORS
703 	ctor_fn_t *call = (ctor_fn_t *) __ctors_start;
704 
705 	for (; call < (ctor_fn_t *) __ctors_end; call++)
706 		(*call)();
707 #endif
708 }
709 
710 int initcall_debug;
711 core_param(initcall_debug, initcall_debug, bool, 0644);
712 
713 static char msgbuf[64];
714 static struct boot_trace_call call;
715 static struct boot_trace_ret ret;
716 
717 int do_one_initcall(initcall_t fn)
718 {
719 	int count = preempt_count();
720 	ktime_t calltime, delta, rettime;
721 
722 	if (initcall_debug) {
723 		call.caller = task_pid_nr(current);
724 		printk("calling  %pF @ %i\n", fn, call.caller);
725 		calltime = ktime_get();
726 		trace_boot_call(&call, fn);
727 		enable_boot_trace();
728 	}
729 
730 	ret.result = fn();
731 
732 	if (initcall_debug) {
733 		disable_boot_trace();
734 		rettime = ktime_get();
735 		delta = ktime_sub(rettime, calltime);
736 		ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
737 		trace_boot_ret(&ret, fn);
738 		printk("initcall %pF returned %d after %Ld usecs\n", fn,
739 			ret.result, ret.duration);
740 	}
741 
742 	msgbuf[0] = 0;
743 
744 	if (ret.result && ret.result != -ENODEV && initcall_debug)
745 		sprintf(msgbuf, "error code %d ", ret.result);
746 
747 	if (preempt_count() != count) {
748 		strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
749 		preempt_count() = count;
750 	}
751 	if (irqs_disabled()) {
752 		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
753 		local_irq_enable();
754 	}
755 	if (msgbuf[0]) {
756 		printk("initcall %pF returned with %s\n", fn, msgbuf);
757 	}
758 
759 	return ret.result;
760 }
761 
762 
763 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
764 
765 static void __init do_initcalls(void)
766 {
767 	initcall_t *call;
768 
769 	for (call = __early_initcall_end; call < __initcall_end; call++)
770 		do_one_initcall(*call);
771 
772 	/* Make sure there is no pending stuff from the initcall sequence */
773 	flush_scheduled_work();
774 }
775 
776 /*
777  * Ok, the machine is now initialized. None of the devices
778  * have been touched yet, but the CPU subsystem is up and
779  * running, and memory and process management works.
780  *
781  * Now we can finally start doing some real work..
782  */
783 static void __init do_basic_setup(void)
784 {
785 	rcu_init_sched(); /* needed by module_init stage. */
786 	init_workqueues();
787 	cpuset_init_smp();
788 	usermodehelper_init();
789 	init_tmpfs();
790 	driver_init();
791 	init_irq_proc();
792 	do_ctors();
793 	do_initcalls();
794 }
795 
796 static void __init do_pre_smp_initcalls(void)
797 {
798 	initcall_t *call;
799 
800 	for (call = __initcall_start; call < __early_initcall_end; call++)
801 		do_one_initcall(*call);
802 }
803 
804 static void run_init_process(char *init_filename)
805 {
806 	argv_init[0] = init_filename;
807 	kernel_execve(init_filename, argv_init, envp_init);
808 }
809 
810 /* This is a non __init function. Force it to be noinline otherwise gcc
811  * makes it inline to init() and it becomes part of init.text section
812  */
813 static noinline int init_post(void)
814 	__releases(kernel_lock)
815 {
816 	/* need to finish all async __init code before freeing the memory */
817 	async_synchronize_full();
818 	free_initmem();
819 	unlock_kernel();
820 	mark_rodata_ro();
821 	system_state = SYSTEM_RUNNING;
822 	numa_default_policy();
823 
824 	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
825 		printk(KERN_WARNING "Warning: unable to open an initial console.\n");
826 
827 	(void) sys_dup(0);
828 	(void) sys_dup(0);
829 
830 	current->signal->flags |= SIGNAL_UNKILLABLE;
831 
832 	if (ramdisk_execute_command) {
833 		run_init_process(ramdisk_execute_command);
834 		printk(KERN_WARNING "Failed to execute %s\n",
835 				ramdisk_execute_command);
836 	}
837 
838 	/*
839 	 * We try each of these until one succeeds.
840 	 *
841 	 * The Bourne shell can be used instead of init if we are
842 	 * trying to recover a really broken machine.
843 	 */
844 	if (execute_command) {
845 		run_init_process(execute_command);
846 		printk(KERN_WARNING "Failed to execute %s.  Attempting "
847 					"defaults...\n", execute_command);
848 	}
849 	run_init_process("/sbin/init");
850 	run_init_process("/etc/init");
851 	run_init_process("/bin/init");
852 	run_init_process("/bin/sh");
853 
854 	panic("No init found.  Try passing init= option to kernel.");
855 }
856 
857 static int __init kernel_init(void * unused)
858 {
859 	lock_kernel();
860 
861 	/*
862 	 * init can allocate pages on any node
863 	 */
864 	set_mems_allowed(node_possible_map);
865 	/*
866 	 * init can run on any cpu.
867 	 */
868 	set_cpus_allowed_ptr(current, cpu_all_mask);
869 	/*
870 	 * Tell the world that we're going to be the grim
871 	 * reaper of innocent orphaned children.
872 	 *
873 	 * We don't want people to have to make incorrect
874 	 * assumptions about where in the task array this
875 	 * can be found.
876 	 */
877 	init_pid_ns.child_reaper = current;
878 
879 	cad_pid = task_pid(current);
880 
881 	smp_prepare_cpus(setup_max_cpus);
882 
883 	do_pre_smp_initcalls();
884 	start_boot_trace();
885 
886 	smp_init();
887 	sched_init_smp();
888 
889 	do_basic_setup();
890 
891 	/*
892 	 * check if there is an early userspace init.  If yes, let it do all
893 	 * the work
894 	 */
895 
896 	if (!ramdisk_execute_command)
897 		ramdisk_execute_command = "/init";
898 
899 	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
900 		ramdisk_execute_command = NULL;
901 		prepare_namespace();
902 	}
903 
904 	/*
905 	 * Ok, we have completed the initial bootup, and
906 	 * we're essentially up and running. Get rid of the
907 	 * initmem segments and start the user-mode stuff..
908 	 */
909 
910 	init_post();
911 	return 0;
912 }
913