xref: /openbmc/linux/init/main.c (revision 495311927ffbe3604e915aeafdf03325e9925b9d)
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/ioport.h>
22 #include <linux/init.h>
23 #include <linux/smp_lock.h>
24 #include <linux/initrd.h>
25 #include <linux/bootmem.h>
26 #include <linux/acpi.h>
27 #include <linux/tty.h>
28 #include <linux/percpu.h>
29 #include <linux/kmod.h>
30 #include <linux/vmalloc.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/start_kernel.h>
33 #include <linux/security.h>
34 #include <linux/smp.h>
35 #include <linux/profile.h>
36 #include <linux/rcupdate.h>
37 #include <linux/moduleparam.h>
38 #include <linux/kallsyms.h>
39 #include <linux/writeback.h>
40 #include <linux/cpu.h>
41 #include <linux/cpuset.h>
42 #include <linux/cgroup.h>
43 #include <linux/efi.h>
44 #include <linux/tick.h>
45 #include <linux/interrupt.h>
46 #include <linux/taskstats_kern.h>
47 #include <linux/delayacct.h>
48 #include <linux/unistd.h>
49 #include <linux/rmap.h>
50 #include <linux/mempolicy.h>
51 #include <linux/key.h>
52 #include <linux/buffer_head.h>
53 #include <linux/page_cgroup.h>
54 #include <linux/debug_locks.h>
55 #include <linux/debugobjects.h>
56 #include <linux/lockdep.h>
57 #include <linux/kmemleak.h>
58 #include <linux/pid_namespace.h>
59 #include <linux/device.h>
60 #include <linux/kthread.h>
61 #include <linux/sched.h>
62 #include <linux/signal.h>
63 #include <linux/idr.h>
64 #include <linux/kgdb.h>
65 #include <linux/ftrace.h>
66 #include <linux/async.h>
67 #include <linux/kmemcheck.h>
68 #include <linux/sfi.h>
69 #include <linux/shmem_fs.h>
70 #include <linux/slab.h>
71 
72 #include <asm/io.h>
73 #include <asm/bugs.h>
74 #include <asm/setup.h>
75 #include <asm/sections.h>
76 #include <asm/cacheflush.h>
77 
78 #ifdef CONFIG_X86_LOCAL_APIC
79 #include <asm/smp.h>
80 #endif
81 
82 static int kernel_init(void *);
83 
84 extern void init_IRQ(void);
85 extern void fork_init(unsigned long);
86 extern void mca_init(void);
87 extern void sbus_init(void);
88 extern void prio_tree_init(void);
89 extern void radix_tree_init(void);
90 extern void free_initmem(void);
91 #ifndef CONFIG_DEBUG_RODATA
92 static inline void mark_rodata_ro(void) { }
93 #endif
94 
95 #ifdef CONFIG_TC
96 extern void tc_init(void);
97 #endif
98 
99 enum system_states system_state __read_mostly;
100 EXPORT_SYMBOL(system_state);
101 
102 /*
103  * Boot command-line arguments
104  */
105 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
106 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
107 
108 extern void time_init(void);
109 /* Default late time init is NULL. archs can override this later. */
110 void (*__initdata late_time_init)(void);
111 extern void softirq_init(void);
112 
113 /* Untouched command line saved by arch-specific code. */
114 char __initdata boot_command_line[COMMAND_LINE_SIZE];
115 /* Untouched saved command line (eg. for /proc) */
116 char *saved_command_line;
117 /* Command line for parameter parsing */
118 static char *static_command_line;
119 
120 static char *execute_command;
121 static char *ramdisk_execute_command;
122 
123 #ifdef CONFIG_SMP
124 /* Setup configured maximum number of CPUs to activate */
125 unsigned int setup_max_cpus = NR_CPUS;
126 EXPORT_SYMBOL(setup_max_cpus);
127 
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 /* this is hard limit */
153 static int __init nrcpus(char *str)
154 {
155 	int nr_cpus;
156 
157 	get_option(&str, &nr_cpus);
158 	if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
159 		nr_cpu_ids = nr_cpus;
160 
161 	return 0;
162 }
163 
164 early_param("nr_cpus", nrcpus);
165 
166 static int __init maxcpus(char *str)
167 {
168 	get_option(&str, &setup_max_cpus);
169 	if (setup_max_cpus == 0)
170 		arch_disable_smp_support();
171 
172 	return 0;
173 }
174 
175 early_param("maxcpus", maxcpus);
176 #else
177 static const unsigned int setup_max_cpus = NR_CPUS;
178 #endif
179 
180 /*
181  * If set, this is an indication to the drivers that reset the underlying
182  * device before going ahead with the initialization otherwise driver might
183  * rely on the BIOS and skip the reset operation.
184  *
185  * This is useful if kernel is booting in an unreliable environment.
186  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
187  * skipped and devices will be in unknown state.
188  */
189 unsigned int reset_devices;
190 EXPORT_SYMBOL(reset_devices);
191 
192 static int __init set_reset_devices(char *str)
193 {
194 	reset_devices = 1;
195 	return 1;
196 }
197 
198 __setup("reset_devices", set_reset_devices);
199 
200 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
201 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
202 static const char *panic_later, *panic_param;
203 
204 extern struct obs_kernel_param __setup_start[], __setup_end[];
205 
206 static int __init obsolete_checksetup(char *line)
207 {
208 	struct obs_kernel_param *p;
209 	int had_early_param = 0;
210 
211 	p = __setup_start;
212 	do {
213 		int n = strlen(p->str);
214 		if (!strncmp(line, p->str, n)) {
215 			if (p->early) {
216 				/* Already done in parse_early_param?
217 				 * (Needs exact match on param part).
218 				 * Keep iterating, as we can have early
219 				 * params and __setups of same names 8( */
220 				if (line[n] == '\0' || line[n] == '=')
221 					had_early_param = 1;
222 			} else if (!p->setup_func) {
223 				printk(KERN_WARNING "Parameter %s is obsolete,"
224 				       " ignored\n", p->str);
225 				return 1;
226 			} else if (p->setup_func(line + n))
227 				return 1;
228 		}
229 		p++;
230 	} while (p < __setup_end);
231 
232 	return had_early_param;
233 }
234 
235 /*
236  * This should be approx 2 Bo*oMips to start (note initial shift), and will
237  * still work even if initially too large, it will just take slightly longer
238  */
239 unsigned long loops_per_jiffy = (1<<12);
240 
241 EXPORT_SYMBOL(loops_per_jiffy);
242 
243 static int __init debug_kernel(char *str)
244 {
245 	console_loglevel = 10;
246 	return 0;
247 }
248 
249 static int __init quiet_kernel(char *str)
250 {
251 	console_loglevel = 4;
252 	return 0;
253 }
254 
255 early_param("debug", debug_kernel);
256 early_param("quiet", quiet_kernel);
257 
258 static int __init loglevel(char *str)
259 {
260 	get_option(&str, &console_loglevel);
261 	return 0;
262 }
263 
264 early_param("loglevel", loglevel);
265 
266 /*
267  * Unknown boot options get handed to init, unless they look like
268  * unused parameters (modprobe will find them in /proc/cmdline).
269  */
270 static int __init unknown_bootoption(char *param, char *val)
271 {
272 	/* Change NUL term back to "=", to make "param" the whole string. */
273 	if (val) {
274 		/* param=val or param="val"? */
275 		if (val == param+strlen(param)+1)
276 			val[-1] = '=';
277 		else if (val == param+strlen(param)+2) {
278 			val[-2] = '=';
279 			memmove(val-1, val, strlen(val)+1);
280 			val--;
281 		} else
282 			BUG();
283 	}
284 
285 	/* Handle obsolete-style parameters */
286 	if (obsolete_checksetup(param))
287 		return 0;
288 
289 	/* Unused module parameter. */
290 	if (strchr(param, '.') && (!val || strchr(param, '.') < val))
291 		return 0;
292 
293 	if (panic_later)
294 		return 0;
295 
296 	if (val) {
297 		/* Environment option */
298 		unsigned int i;
299 		for (i = 0; envp_init[i]; i++) {
300 			if (i == MAX_INIT_ENVS) {
301 				panic_later = "Too many boot env vars at `%s'";
302 				panic_param = param;
303 			}
304 			if (!strncmp(param, envp_init[i], val - param))
305 				break;
306 		}
307 		envp_init[i] = param;
308 	} else {
309 		/* Command line option */
310 		unsigned int i;
311 		for (i = 0; argv_init[i]; i++) {
312 			if (i == MAX_INIT_ARGS) {
313 				panic_later = "Too many boot init vars at `%s'";
314 				panic_param = param;
315 			}
316 		}
317 		argv_init[i] = param;
318 	}
319 	return 0;
320 }
321 
322 #ifdef CONFIG_DEBUG_PAGEALLOC
323 int __read_mostly debug_pagealloc_enabled = 0;
324 #endif
325 
326 static int __init init_setup(char *str)
327 {
328 	unsigned int i;
329 
330 	execute_command = str;
331 	/*
332 	 * In case LILO is going to boot us with default command line,
333 	 * it prepends "auto" before the whole cmdline which makes
334 	 * the shell think it should execute a script with such name.
335 	 * So we ignore all arguments entered _before_ init=... [MJ]
336 	 */
337 	for (i = 1; i < MAX_INIT_ARGS; i++)
338 		argv_init[i] = NULL;
339 	return 1;
340 }
341 __setup("init=", init_setup);
342 
343 static int __init rdinit_setup(char *str)
344 {
345 	unsigned int i;
346 
347 	ramdisk_execute_command = str;
348 	/* See "auto" comment in init_setup */
349 	for (i = 1; i < MAX_INIT_ARGS; i++)
350 		argv_init[i] = NULL;
351 	return 1;
352 }
353 __setup("rdinit=", rdinit_setup);
354 
355 #ifndef CONFIG_SMP
356 
357 #ifdef CONFIG_X86_LOCAL_APIC
358 static void __init smp_init(void)
359 {
360 	APIC_init_uniprocessor();
361 }
362 #else
363 #define smp_init()	do { } while (0)
364 #endif
365 
366 static inline void setup_nr_cpu_ids(void) { }
367 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
368 
369 #else
370 
371 /* Setup number of possible processor ids */
372 int nr_cpu_ids __read_mostly = NR_CPUS;
373 EXPORT_SYMBOL(nr_cpu_ids);
374 
375 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
376 static void __init setup_nr_cpu_ids(void)
377 {
378 	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
379 }
380 
381 /* Called by boot processor to activate the rest. */
382 static void __init smp_init(void)
383 {
384 	unsigned int cpu;
385 
386 	/* FIXME: This should be done in userspace --RR */
387 	for_each_present_cpu(cpu) {
388 		if (num_online_cpus() >= setup_max_cpus)
389 			break;
390 		if (!cpu_online(cpu))
391 			cpu_up(cpu);
392 	}
393 
394 	/* Any cleanup work */
395 	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
396 	smp_cpus_done(setup_max_cpus);
397 }
398 
399 #endif
400 
401 /*
402  * We need to store the untouched command line for future reference.
403  * We also need to store the touched command line since the parameter
404  * parsing is performed in place, and we should allow a component to
405  * store reference of name/value for future reference.
406  */
407 static void __init setup_command_line(char *command_line)
408 {
409 	saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
410 	static_command_line = alloc_bootmem(strlen (command_line)+1);
411 	strcpy (saved_command_line, boot_command_line);
412 	strcpy (static_command_line, command_line);
413 }
414 
415 /*
416  * We need to finalize in a non-__init function or else race conditions
417  * between the root thread and the init thread may cause start_kernel to
418  * be reaped by free_initmem before the root thread has proceeded to
419  * cpu_idle.
420  *
421  * gcc-3.4 accidentally inlines this function, so use noinline.
422  */
423 
424 static __initdata DECLARE_COMPLETION(kthreadd_done);
425 
426 static noinline void __init_refok rest_init(void)
427 	__releases(kernel_lock)
428 {
429 	int pid;
430 
431 	rcu_scheduler_starting();
432 	/*
433 	 * We need to spawn init first so that it obtains pid 1, however
434 	 * the init task will end up wanting to create kthreads, which, if
435 	 * we schedule it before we create kthreadd, will OOPS.
436 	 */
437 	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
438 	numa_default_policy();
439 	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
440 	rcu_read_lock();
441 	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
442 	rcu_read_unlock();
443 	complete(&kthreadd_done);
444 
445 	/*
446 	 * The boot idle thread must execute schedule()
447 	 * at least once to get things moving:
448 	 */
449 	init_idle_bootup_task(current);
450 	preempt_enable_no_resched();
451 	schedule();
452 	preempt_disable();
453 
454 	/* Call into cpu_idle with preempt disabled */
455 	cpu_idle();
456 }
457 
458 /* Check for early params. */
459 static int __init do_early_param(char *param, char *val)
460 {
461 	struct obs_kernel_param *p;
462 
463 	for (p = __setup_start; p < __setup_end; p++) {
464 		if ((p->early && strcmp(param, p->str) == 0) ||
465 		    (strcmp(param, "console") == 0 &&
466 		     strcmp(p->str, "earlycon") == 0)
467 		) {
468 			if (p->setup_func(val) != 0)
469 				printk(KERN_WARNING
470 				       "Malformed early option '%s'\n", param);
471 		}
472 	}
473 	/* We accept everything at this stage. */
474 	return 0;
475 }
476 
477 void __init parse_early_options(char *cmdline)
478 {
479 	parse_args("early options", cmdline, NULL, 0, do_early_param);
480 }
481 
482 /* Arch code calls this early on, or if not, just before other parsing. */
483 void __init parse_early_param(void)
484 {
485 	static __initdata int done = 0;
486 	static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
487 
488 	if (done)
489 		return;
490 
491 	/* All fall through to do_early_param. */
492 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
493 	parse_early_options(tmp_cmdline);
494 	done = 1;
495 }
496 
497 /*
498  *	Activate the first processor.
499  */
500 
501 static void __init boot_cpu_init(void)
502 {
503 	int cpu = smp_processor_id();
504 	/* Mark the boot cpu "present", "online" etc for SMP and UP case */
505 	set_cpu_online(cpu, true);
506 	set_cpu_active(cpu, true);
507 	set_cpu_present(cpu, true);
508 	set_cpu_possible(cpu, true);
509 }
510 
511 void __init __weak smp_setup_processor_id(void)
512 {
513 }
514 
515 void __init __weak thread_info_cache_init(void)
516 {
517 }
518 
519 /*
520  * Set up kernel memory allocators
521  */
522 static void __init mm_init(void)
523 {
524 	/*
525 	 * page_cgroup requires countinous pages as memmap
526 	 * and it's bigger than MAX_ORDER unless SPARSEMEM.
527 	 */
528 	page_cgroup_init_flatmem();
529 	mem_init();
530 	kmem_cache_init();
531 	percpu_init_late();
532 	pgtable_cache_init();
533 	vmalloc_init();
534 }
535 
536 asmlinkage void __init start_kernel(void)
537 {
538 	char * command_line;
539 	extern struct kernel_param __start___param[], __stop___param[];
540 
541 	smp_setup_processor_id();
542 
543 	/*
544 	 * Need to run as early as possible, to initialize the
545 	 * lockdep hash:
546 	 */
547 	lockdep_init();
548 	debug_objects_early_init();
549 
550 	/*
551 	 * Set up the the initial canary ASAP:
552 	 */
553 	boot_init_stack_canary();
554 
555 	cgroup_init_early();
556 
557 	local_irq_disable();
558 	early_boot_irqs_off();
559 	early_init_irq_lock_class();
560 
561 /*
562  * Interrupts are still disabled. Do necessary setups, then
563  * enable them
564  */
565 	tick_init();
566 	boot_cpu_init();
567 	page_address_init();
568 	printk(KERN_NOTICE "%s", linux_banner);
569 	setup_arch(&command_line);
570 	mm_init_owner(&init_mm, &init_task);
571 	setup_command_line(command_line);
572 	setup_nr_cpu_ids();
573 	setup_per_cpu_areas();
574 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
575 
576 	build_all_zonelists(NULL);
577 	page_alloc_init();
578 
579 	printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
580 	parse_early_param();
581 	parse_args("Booting kernel", static_command_line, __start___param,
582 		   __stop___param - __start___param,
583 		   &unknown_bootoption);
584 	/*
585 	 * These use large bootmem allocations and must precede
586 	 * kmem_cache_init()
587 	 */
588 	pidhash_init();
589 	vfs_caches_init_early();
590 	sort_main_extable();
591 	trap_init();
592 	mm_init();
593 	/*
594 	 * Set up the scheduler prior starting any interrupts (such as the
595 	 * timer interrupt). Full topology setup happens at smp_init()
596 	 * time - but meanwhile we still have a functioning scheduler.
597 	 */
598 	sched_init();
599 	/*
600 	 * Disable preemption - early bootup scheduling is extremely
601 	 * fragile until we cpu_idle() for the first time.
602 	 */
603 	preempt_disable();
604 	if (!irqs_disabled()) {
605 		printk(KERN_WARNING "start_kernel(): bug: interrupts were "
606 				"enabled *very* early, fixing it\n");
607 		local_irq_disable();
608 	}
609 	rcu_init();
610 	radix_tree_init();
611 	/* init some links before init_ISA_irqs() */
612 	early_irq_init();
613 	init_IRQ();
614 	prio_tree_init();
615 	init_timers();
616 	hrtimers_init();
617 	softirq_init();
618 	timekeeping_init();
619 	time_init();
620 	profile_init();
621 	if (!irqs_disabled())
622 		printk(KERN_CRIT "start_kernel(): bug: interrupts were "
623 				 "enabled early\n");
624 	early_boot_irqs_on();
625 	local_irq_enable();
626 
627 	/* Interrupts are enabled now so all GFP allocations are safe. */
628 	gfp_allowed_mask = __GFP_BITS_MASK;
629 
630 	kmem_cache_init_late();
631 
632 	/*
633 	 * HACK ALERT! This is early. We're enabling the console before
634 	 * we've done PCI setups etc, and console_init() must be aware of
635 	 * this. But we do want output early, in case something goes wrong.
636 	 */
637 	console_init();
638 	if (panic_later)
639 		panic(panic_later, panic_param);
640 
641 	lockdep_info();
642 
643 	/*
644 	 * Need to run this when irqs are enabled, because it wants
645 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
646 	 * too:
647 	 */
648 	locking_selftest();
649 
650 #ifdef CONFIG_BLK_DEV_INITRD
651 	if (initrd_start && !initrd_below_start_ok &&
652 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
653 		printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
654 		    "disabling it.\n",
655 		    page_to_pfn(virt_to_page((void *)initrd_start)),
656 		    min_low_pfn);
657 		initrd_start = 0;
658 	}
659 #endif
660 	page_cgroup_init();
661 	enable_debug_pagealloc();
662 	kmemleak_init();
663 	debug_objects_mem_init();
664 	idr_init_cache();
665 	setup_per_cpu_pageset();
666 	numa_policy_init();
667 	if (late_time_init)
668 		late_time_init();
669 	sched_clock_init();
670 	calibrate_delay();
671 	pidmap_init();
672 	anon_vma_init();
673 #ifdef CONFIG_X86
674 	if (efi_enabled)
675 		efi_enter_virtual_mode();
676 #endif
677 	thread_info_cache_init();
678 	cred_init();
679 	fork_init(totalram_pages);
680 	proc_caches_init();
681 	buffer_init();
682 	key_init();
683 	security_init();
684 	dbg_late_init();
685 	vfs_caches_init(totalram_pages);
686 	signals_init();
687 	/* rootfs populating might need page-writeback */
688 	page_writeback_init();
689 #ifdef CONFIG_PROC_FS
690 	proc_root_init();
691 #endif
692 	cgroup_init();
693 	cpuset_init();
694 	taskstats_init_early();
695 	delayacct_init();
696 
697 	check_bugs();
698 
699 	acpi_early_init(); /* before LAPIC and SMP init */
700 	sfi_init_late();
701 
702 	ftrace_init();
703 
704 	/* Do the rest non-__init'ed, we're now alive */
705 	rest_init();
706 }
707 
708 /* Call all constructor functions linked into the kernel. */
709 static void __init do_ctors(void)
710 {
711 #ifdef CONFIG_CONSTRUCTORS
712 	ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
713 
714 	for (; fn < (ctor_fn_t *) __ctors_end; fn++)
715 		(*fn)();
716 #endif
717 }
718 
719 int initcall_debug;
720 core_param(initcall_debug, initcall_debug, bool, 0644);
721 
722 static char msgbuf[64];
723 
724 static int __init_or_module do_one_initcall_debug(initcall_t fn)
725 {
726 	ktime_t calltime, delta, rettime;
727 	unsigned long long duration;
728 	int ret;
729 
730 	printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
731 	calltime = ktime_get();
732 	ret = fn();
733 	rettime = ktime_get();
734 	delta = ktime_sub(rettime, calltime);
735 	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
736 	printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
737 		ret, duration);
738 
739 	return ret;
740 }
741 
742 int __init_or_module do_one_initcall(initcall_t fn)
743 {
744 	int count = preempt_count();
745 	int ret;
746 
747 	if (initcall_debug)
748 		ret = do_one_initcall_debug(fn);
749 	else
750 		ret = fn();
751 
752 	msgbuf[0] = 0;
753 
754 	if (ret && ret != -ENODEV && initcall_debug)
755 		sprintf(msgbuf, "error code %d ", ret);
756 
757 	if (preempt_count() != count) {
758 		strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
759 		preempt_count() = count;
760 	}
761 	if (irqs_disabled()) {
762 		strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
763 		local_irq_enable();
764 	}
765 	if (msgbuf[0]) {
766 		printk("initcall %pF returned with %s\n", fn, msgbuf);
767 	}
768 
769 	return ret;
770 }
771 
772 
773 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
774 
775 static void __init do_initcalls(void)
776 {
777 	initcall_t *fn;
778 
779 	for (fn = __early_initcall_end; fn < __initcall_end; fn++)
780 		do_one_initcall(*fn);
781 
782 	/* Make sure there is no pending stuff from the initcall sequence */
783 	flush_scheduled_work();
784 }
785 
786 /*
787  * Ok, the machine is now initialized. None of the devices
788  * have been touched yet, but the CPU subsystem is up and
789  * running, and memory and process management works.
790  *
791  * Now we can finally start doing some real work..
792  */
793 static void __init do_basic_setup(void)
794 {
795 	cpuset_init_smp();
796 	usermodehelper_init();
797 	init_tmpfs();
798 	driver_init();
799 	init_irq_proc();
800 	do_ctors();
801 	do_initcalls();
802 }
803 
804 static void __init do_pre_smp_initcalls(void)
805 {
806 	initcall_t *fn;
807 
808 	for (fn = __initcall_start; fn < __early_initcall_end; fn++)
809 		do_one_initcall(*fn);
810 }
811 
812 static void run_init_process(char *init_filename)
813 {
814 	argv_init[0] = init_filename;
815 	kernel_execve(init_filename, argv_init, envp_init);
816 }
817 
818 /* This is a non __init function. Force it to be noinline otherwise gcc
819  * makes it inline to init() and it becomes part of init.text section
820  */
821 static noinline int init_post(void)
822 	__releases(kernel_lock)
823 {
824 	/* need to finish all async __init code before freeing the memory */
825 	async_synchronize_full();
826 	free_initmem();
827 	mark_rodata_ro();
828 	system_state = SYSTEM_RUNNING;
829 	numa_default_policy();
830 
831 
832 	current->signal->flags |= SIGNAL_UNKILLABLE;
833 
834 	if (ramdisk_execute_command) {
835 		run_init_process(ramdisk_execute_command);
836 		printk(KERN_WARNING "Failed to execute %s\n",
837 				ramdisk_execute_command);
838 	}
839 
840 	/*
841 	 * We try each of these until one succeeds.
842 	 *
843 	 * The Bourne shell can be used instead of init if we are
844 	 * trying to recover a really broken machine.
845 	 */
846 	if (execute_command) {
847 		run_init_process(execute_command);
848 		printk(KERN_WARNING "Failed to execute %s.  Attempting "
849 					"defaults...\n", execute_command);
850 	}
851 	run_init_process("/sbin/init");
852 	run_init_process("/etc/init");
853 	run_init_process("/bin/init");
854 	run_init_process("/bin/sh");
855 
856 	panic("No init found.  Try passing init= option to kernel. "
857 	      "See Linux Documentation/init.txt for guidance.");
858 }
859 
860 static int __init kernel_init(void * unused)
861 {
862 	/*
863 	 * Wait until kthreadd is all set-up.
864 	 */
865 	wait_for_completion(&kthreadd_done);
866 	/*
867 	 * init can allocate pages on any node
868 	 */
869 	set_mems_allowed(node_states[N_HIGH_MEMORY]);
870 	/*
871 	 * init can run on any cpu.
872 	 */
873 	set_cpus_allowed_ptr(current, cpu_all_mask);
874 	/*
875 	 * Tell the world that we're going to be the grim
876 	 * reaper of innocent orphaned children.
877 	 *
878 	 * We don't want people to have to make incorrect
879 	 * assumptions about where in the task array this
880 	 * can be found.
881 	 */
882 	init_pid_ns.child_reaper = current;
883 
884 	cad_pid = task_pid(current);
885 
886 	smp_prepare_cpus(setup_max_cpus);
887 
888 	do_pre_smp_initcalls();
889 
890 	smp_init();
891 	sched_init_smp();
892 
893 	do_basic_setup();
894 
895 	/* Open the /dev/console on the rootfs, this should never fail */
896 	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
897 		printk(KERN_WARNING "Warning: unable to open an initial console.\n");
898 
899 	(void) sys_dup(0);
900 	(void) sys_dup(0);
901 	/*
902 	 * check if there is an early userspace init.  If yes, let it do all
903 	 * the work
904 	 */
905 
906 	if (!ramdisk_execute_command)
907 		ramdisk_execute_command = "/init";
908 
909 	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
910 		ramdisk_execute_command = NULL;
911 		prepare_namespace();
912 	}
913 
914 	/*
915 	 * Ok, we have completed the initial bootup, and
916 	 * we're essentially up and running. Get rid of the
917 	 * initmem segments and start the user-mode stuff..
918 	 */
919 
920 	init_post();
921 	return 0;
922 }
923