projects/linux·blob v3.7 · refs

902 lines · 21.5 KiB

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 <[email protected]>
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/initrd.h>
24#include <linux/bootmem.h>
25#include <linux/acpi.h>
26#include <linux/tty.h>
27#include <linux/percpu.h>
28#include <linux/kmod.h>
29#include <linux/vmalloc.h>
30#include <linux/kernel_stat.h>
31#include <linux/start_kernel.h>
32#include <linux/security.h>
33#include <linux/smp.h>
34#include <linux/profile.h>
35#include <linux/rcupdate.h>
36#include <linux/moduleparam.h>
37#include <linux/kallsyms.h>
38#include <linux/writeback.h>
39#include <linux/cpu.h>
40#include <linux/cpuset.h>
41#include <linux/cgroup.h>
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>
47#include <linux/unistd.h>
48#include <linux/rmap.h>
49#include <linux/mempolicy.h>
50#include <linux/key.h>
51#include <linux/buffer_head.h>
52#include <linux/page_cgroup.h>
53#include <linux/debug_locks.h>
54#include <linux/debugobjects.h>
55#include <linux/lockdep.h>
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>
71#include <linux/file.h>
72#include <linux/ptrace.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
84static int kernel_init(void *);
85
86extern void init_IRQ(void);
87extern void fork_init(unsigned long);
88extern void mca_init(void);
89extern void sbus_init(void);
90extern void radix_tree_init(void);
91#ifndef CONFIG_DEBUG_RODATA
92static inline void mark_rodata_ro(void) { }
93#endif
94
95#ifdef CONFIG_TC
96extern void tc_init(void);
97#endif
98
99/*
100 * Debug helper: via this flag we know that we are in 'early bootup code'
101 * where only the boot processor is running with IRQ disabled. This means
102 * two things - IRQ must not be enabled before the flag is cleared and some
103 * operations which are not allowed with IRQ disabled are allowed while the
104 * flag is set.
105 */
106bool early_boot_irqs_disabled __read_mostly;
107
108enum system_states system_state __read_mostly;
109EXPORT_SYMBOL(system_state);
110
111/*
112 * Boot command-line arguments
113 */
114#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
115#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
116
117extern void time_init(void);
118/* Default late time init is NULL. archs can override this later. */
119void (*__initdata late_time_init)(void);
120extern void softirq_init(void);
121
122/* Untouched command line saved by arch-specific code. */
123char __initdata boot_command_line[COMMAND_LINE_SIZE];
124/* Untouched saved command line (eg. for /proc) */
125char *saved_command_line;
126/* Command line for parameter parsing */
127static char *static_command_line;
128
129static char *execute_command;
130static char *ramdisk_execute_command;
131
132/*
133 * If set, this is an indication to the drivers that reset the underlying
134 * device before going ahead with the initialization otherwise driver might
135 * rely on the BIOS and skip the reset operation.
136 *
137 * This is useful if kernel is booting in an unreliable environment.
138 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
139 * skipped and devices will be in unknown state.
140 */
141unsigned int reset_devices;
142EXPORT_SYMBOL(reset_devices);
143
144static int __init set_reset_devices(char *str)
145{
146 reset_devices = 1;
147 return 1;
148}
149
150__setup("reset_devices", set_reset_devices);
151
152static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
153const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
154static const char *panic_later, *panic_param;
155
156extern const struct obs_kernel_param __setup_start[], __setup_end[];
157
158static int __init obsolete_checksetup(char *line)
159{
160 const struct obs_kernel_param *p;
161 int had_early_param = 0;
162
163 p = __setup_start;
164 do {
165 int n = strlen(p->str);
166 if (parameqn(line, p->str, n)) {
167 if (p->early) {
168 /* Already done in parse_early_param?
169 * (Needs exact match on param part).
170 * Keep iterating, as we can have early
171 * params and __setups of same names 8( */
172 if (line[n] == '\0' || line[n] == '=')
173 had_early_param = 1;
174 } else if (!p->setup_func) {
175 printk(KERN_WARNING "Parameter %s is obsolete,"
176 " ignored\n", p->str);
177 return 1;
178 } else if (p->setup_func(line + n))
179 return 1;
180 }
181 p++;
182 } while (p < __setup_end);
183
184 return had_early_param;
185}
186
187/*
188 * This should be approx 2 Bo*oMips to start (note initial shift), and will
189 * still work even if initially too large, it will just take slightly longer
190 */
191unsigned long loops_per_jiffy = (1<<12);
192
193EXPORT_SYMBOL(loops_per_jiffy);
194
195static int __init debug_kernel(char *str)
196{
197 console_loglevel = 10;
198 return 0;
199}
200
201static int __init quiet_kernel(char *str)
202{
203 console_loglevel = 4;
204 return 0;
205}
206
207early_param("debug", debug_kernel);
208early_param("quiet", quiet_kernel);
209
210static int __init loglevel(char *str)
211{
212 int newlevel;
213
214 /*
215 * Only update loglevel value when a correct setting was passed,
216 * to prevent blind crashes (when loglevel being set to 0) that
217 * are quite hard to debug
218 */
219 if (get_option(&str, &newlevel)) {
220 console_loglevel = newlevel;
221 return 0;
222 }
223
224 return -EINVAL;
225}
226
227early_param("loglevel", loglevel);
228
229/* Change NUL term back to "=", to make "param" the whole string. */
230static int __init repair_env_string(char *param, char *val, const char *unused)
231{
232 if (val) {
233 /* param=val or param="val"? */
234 if (val == param+strlen(param)+1)
235 val[-1] = '=';
236 else if (val == param+strlen(param)+2) {
237 val[-2] = '=';
238 memmove(val-1, val, strlen(val)+1);
239 val--;
240 } else
241 BUG();
242 }
243 return 0;
244}
245
246/*
247 * Unknown boot options get handed to init, unless they look like
248 * unused parameters (modprobe will find them in /proc/cmdline).
249 */
250static int __init unknown_bootoption(char *param, char *val, const char *unused)
251{
252 repair_env_string(param, val, unused);
253
254 /* Handle obsolete-style parameters */
255 if (obsolete_checksetup(param))
256 return 0;
257
258 /* Unused module parameter. */
259 if (strchr(param, '.') && (!val || strchr(param, '.') < val))
260 return 0;
261
262 if (panic_later)
263 return 0;
264
265 if (val) {
266 /* Environment option */
267 unsigned int i;
268 for (i = 0; envp_init[i]; i++) {
269 if (i == MAX_INIT_ENVS) {
270 panic_later = "Too many boot env vars at `%s'";
271 panic_param = param;
272 }
273 if (!strncmp(param, envp_init[i], val - param))
274 break;
275 }
276 envp_init[i] = param;
277 } else {
278 /* Command line option */
279 unsigned int i;
280 for (i = 0; argv_init[i]; i++) {
281 if (i == MAX_INIT_ARGS) {
282 panic_later = "Too many boot init vars at `%s'";
283 panic_param = param;
284 }
285 }
286 argv_init[i] = param;
287 }
288 return 0;
289}
290
291static int __init init_setup(char *str)
292{
293 unsigned int i;
294
295 execute_command = str;
296 /*
297 * In case LILO is going to boot us with default command line,
298 * it prepends "auto" before the whole cmdline which makes
299 * the shell think it should execute a script with such name.
300 * So we ignore all arguments entered _before_ init=... [MJ]
301 */
302 for (i = 1; i < MAX_INIT_ARGS; i++)
303 argv_init[i] = NULL;
304 return 1;
305}
306__setup("init=", init_setup);
307
308static int __init rdinit_setup(char *str)
309{
310 unsigned int i;
311
312 ramdisk_execute_command = str;
313 /* See "auto" comment in init_setup */
314 for (i = 1; i < MAX_INIT_ARGS; i++)
315 argv_init[i] = NULL;
316 return 1;
317}
318__setup("rdinit=", rdinit_setup);
319
320#ifndef CONFIG_SMP
321static const unsigned int setup_max_cpus = NR_CPUS;
322#ifdef CONFIG_X86_LOCAL_APIC
323static void __init smp_init(void)
324{
325 APIC_init_uniprocessor();
326}
327#else
328#define smp_init() do { } while (0)
329#endif
330
331static inline void setup_nr_cpu_ids(void) { }
332static inline void smp_prepare_cpus(unsigned int maxcpus) { }
333#endif
334
335/*
336 * We need to store the untouched command line for future reference.
337 * We also need to store the touched command line since the parameter
338 * parsing is performed in place, and we should allow a component to
339 * store reference of name/value for future reference.
340 */
341static void __init setup_command_line(char *command_line)
342{
343 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
344 static_command_line = alloc_bootmem(strlen (command_line)+1);
345 strcpy (saved_command_line, boot_command_line);
346 strcpy (static_command_line, command_line);
347}
348
349/*
350 * We need to finalize in a non-__init function or else race conditions
351 * between the root thread and the init thread may cause start_kernel to
352 * be reaped by free_initmem before the root thread has proceeded to
353 * cpu_idle.
354 *
355 * gcc-3.4 accidentally inlines this function, so use noinline.
356 */
357
358static __initdata DECLARE_COMPLETION(kthreadd_done);
359
360static noinline void __init_refok rest_init(void)
361{
362 int pid;
363
364 rcu_scheduler_starting();
365 /*
366 * We need to spawn init first so that it obtains pid 1, however
367 * the init task will end up wanting to create kthreads, which, if
368 * we schedule it before we create kthreadd, will OOPS.
369 */
370 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
371 numa_default_policy();
372 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
373 rcu_read_lock();
374 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
375 rcu_read_unlock();
376 complete(&kthreadd_done);
377
378 /*
379 * The boot idle thread must execute schedule()
380 * at least once to get things moving:
381 */
382 init_idle_bootup_task(current);
383 schedule_preempt_disabled();
384 /* Call into cpu_idle with preempt disabled */
385 cpu_idle();
386}
387
388/* Check for early params. */
389static int __init do_early_param(char *param, char *val, const char *unused)
390{
391 const struct obs_kernel_param *p;
392
393 for (p = __setup_start; p < __setup_end; p++) {
394 if ((p->early && parameq(param, p->str)) ||
395 (strcmp(param, "console") == 0 &&
396 strcmp(p->str, "earlycon") == 0)
397 ) {
398 if (p->setup_func(val) != 0)
399 printk(KERN_WARNING
400 "Malformed early option '%s'\n", param);
401 }
402 }
403 /* We accept everything at this stage. */
404 return 0;
405}
406
407void __init parse_early_options(char *cmdline)
408{
409 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
410}
411
412/* Arch code calls this early on, or if not, just before other parsing. */
413void __init parse_early_param(void)
414{
415 static __initdata int done = 0;
416 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
417
418 if (done)
419 return;
420
421 /* All fall through to do_early_param. */
422 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
423 parse_early_options(tmp_cmdline);
424 done = 1;
425}
426
427/*
428 * Activate the first processor.
429 */
430
431static void __init boot_cpu_init(void)
432{
433 int cpu = smp_processor_id();
434 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
435 set_cpu_online(cpu, true);
436 set_cpu_active(cpu, true);
437 set_cpu_present(cpu, true);
438 set_cpu_possible(cpu, true);
439}
440
441void __init __weak smp_setup_processor_id(void)
442{
443}
444
445# if THREAD_SIZE >= PAGE_SIZE
446void __init __weak thread_info_cache_init(void)
447{
448}
449#endif
450
451/*
452 * Set up kernel memory allocators
453 */
454static void __init mm_init(void)
455{
456 /*
457 * page_cgroup requires contiguous pages,
458 * bigger than MAX_ORDER unless SPARSEMEM.
459 */
460 page_cgroup_init_flatmem();
461 mem_init();
462 kmem_cache_init();
463 percpu_init_late();
464 pgtable_cache_init();
465 vmalloc_init();
466}
467
468asmlinkage void __init start_kernel(void)
469{
470 char * command_line;
471 extern const struct kernel_param __start___param[], __stop___param[];
472
473 /*
474 * Need to run as early as possible, to initialize the
475 * lockdep hash:
476 */
477 lockdep_init();
478 smp_setup_processor_id();
479 debug_objects_early_init();
480
481 /*
482 * Set up the the initial canary ASAP:
483 */
484 boot_init_stack_canary();
485
486 cgroup_init_early();
487
488 local_irq_disable();
489 early_boot_irqs_disabled = true;
490
491/*
492 * Interrupts are still disabled. Do necessary setups, then
493 * enable them
494 */
495 tick_init();
496 boot_cpu_init();
497 page_address_init();
498 printk(KERN_NOTICE "%s", linux_banner);
499 setup_arch(&command_line);
500 mm_init_owner(&init_mm, &init_task);
501 mm_init_cpumask(&init_mm);
502 setup_command_line(command_line);
503 setup_nr_cpu_ids();
504 setup_per_cpu_areas();
505 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
506
507 build_all_zonelists(NULL, NULL);
508 page_alloc_init();
509
510 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
511 parse_early_param();
512 parse_args("Booting kernel", static_command_line, __start___param,
513 __stop___param - __start___param,
514 -1, -1, &unknown_bootoption);
515
516 jump_label_init();
517
518 /*
519 * These use large bootmem allocations and must precede
520 * kmem_cache_init()
521 */
522 setup_log_buf(0);
523 pidhash_init();
524 vfs_caches_init_early();
525 sort_main_extable();
526 trap_init();
527 mm_init();
528
529 /*
530 * Set up the scheduler prior starting any interrupts (such as the
531 * timer interrupt). Full topology setup happens at smp_init()
532 * time - but meanwhile we still have a functioning scheduler.
533 */
534 sched_init();
535 /*
536 * Disable preemption - early bootup scheduling is extremely
537 * fragile until we cpu_idle() for the first time.
538 */
539 preempt_disable();
540 if (!irqs_disabled()) {
541 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
542 "enabled *very* early, fixing it\n");
543 local_irq_disable();
544 }
545 idr_init_cache();
546 perf_event_init();
547 rcu_init();
548 radix_tree_init();
549 /* init some links before init_ISA_irqs() */
550 early_irq_init();
551 init_IRQ();
552 init_timers();
553 hrtimers_init();
554 softirq_init();
555 timekeeping_init();
556 time_init();
557 profile_init();
558 call_function_init();
559 if (!irqs_disabled())
560 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
561 "enabled early\n");
562 early_boot_irqs_disabled = false;
563 local_irq_enable();
564
565 kmem_cache_init_late();
566
567 /*
568 * HACK ALERT! This is early. We're enabling the console before
569 * we've done PCI setups etc, and console_init() must be aware of
570 * this. But we do want output early, in case something goes wrong.
571 */
572 console_init();
573 if (panic_later)
574 panic(panic_later, panic_param);
575
576 lockdep_info();
577
578 /*
579 * Need to run this when irqs are enabled, because it wants
580 * to self-test [hard/soft]-irqs on/off lock inversion bugs
581 * too:
582 */
583 locking_selftest();
584
585#ifdef CONFIG_BLK_DEV_INITRD
586 if (initrd_start && !initrd_below_start_ok &&
587 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
588 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
589 "disabling it.\n",
590 page_to_pfn(virt_to_page((void *)initrd_start)),
591 min_low_pfn);
592 initrd_start = 0;
593 }
594#endif
595 page_cgroup_init();
596 debug_objects_mem_init();
597 kmemleak_init();
598 setup_per_cpu_pageset();
599 numa_policy_init();
600 if (late_time_init)
601 late_time_init();
602 sched_clock_init();
603 calibrate_delay();
604 pidmap_init();
605 anon_vma_init();
606#ifdef CONFIG_X86
607 if (efi_enabled)
608 efi_enter_virtual_mode();
609#endif
610 thread_info_cache_init();
611 cred_init();
612 fork_init(totalram_pages);
613 proc_caches_init();
614 buffer_init();
615 key_init();
616 security_init();
617 dbg_late_init();
618 vfs_caches_init(totalram_pages);
619 signals_init();
620 /* rootfs populating might need page-writeback */
621 page_writeback_init();
622#ifdef CONFIG_PROC_FS
623 proc_root_init();
624#endif
625 cgroup_init();
626 cpuset_init();
627 taskstats_init_early();
628 delayacct_init();
629
630 check_bugs();
631
632 acpi_early_init(); /* before LAPIC and SMP init */
633 sfi_init_late();
634
635 if (efi_enabled) {
636 efi_late_init();
637 efi_free_boot_services();
638 }
639
640 ftrace_init();
641
642 /* Do the rest non-__init'ed, we're now alive */
643 rest_init();
644}
645
646/* Call all constructor functions linked into the kernel. */
647static void __init do_ctors(void)
648{
649#ifdef CONFIG_CONSTRUCTORS
650 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
651
652 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
653 (*fn)();
654#endif
655}
656
657bool initcall_debug;
658core_param(initcall_debug, initcall_debug, bool, 0644);
659
660static char msgbuf[64];
661
662static int __init_or_module do_one_initcall_debug(initcall_t fn)
663{
664 ktime_t calltime, delta, rettime;
665 unsigned long long duration;
666 int ret;
667
668 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
669 calltime = ktime_get();
670 ret = fn();
671 rettime = ktime_get();
672 delta = ktime_sub(rettime, calltime);
673 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
674 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
675 ret, duration);
676
677 return ret;
678}
679
680int __init_or_module do_one_initcall(initcall_t fn)
681{
682 int count = preempt_count();
683 int ret;
684
685 if (initcall_debug)
686 ret = do_one_initcall_debug(fn);
687 else
688 ret = fn();
689
690 msgbuf[0] = 0;
691
692 if (ret && ret != -ENODEV && initcall_debug)
693 sprintf(msgbuf, "error code %d ", ret);
694
695 if (preempt_count() != count) {
696 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
697 preempt_count() = count;
698 }
699 if (irqs_disabled()) {
700 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
701 local_irq_enable();
702 }
703 if (msgbuf[0]) {
704 printk("initcall %pF returned with %s\n", fn, msgbuf);
705 }
706
707 return ret;
708}
709
710
711extern initcall_t __initcall_start[];
712extern initcall_t __initcall0_start[];
713extern initcall_t __initcall1_start[];
714extern initcall_t __initcall2_start[];
715extern initcall_t __initcall3_start[];
716extern initcall_t __initcall4_start[];
717extern initcall_t __initcall5_start[];
718extern initcall_t __initcall6_start[];
719extern initcall_t __initcall7_start[];
720extern initcall_t __initcall_end[];
721
722static initcall_t *initcall_levels[] __initdata = {
723 __initcall0_start,
724 __initcall1_start,
725 __initcall2_start,
726 __initcall3_start,
727 __initcall4_start,
728 __initcall5_start,
729 __initcall6_start,
730 __initcall7_start,
731 __initcall_end,
732};
733
734/* Keep these in sync with initcalls in include/linux/init.h */
735static char *initcall_level_names[] __initdata = {
736 "early",
737 "core",
738 "postcore",
739 "arch",
740 "subsys",
741 "fs",
742 "device",
743 "late",
744};
745
746static void __init do_initcall_level(int level)
747{
748 extern const struct kernel_param __start___param[], __stop___param[];
749 initcall_t *fn;
750
751 strcpy(static_command_line, saved_command_line);
752 parse_args(initcall_level_names[level],
753 static_command_line, __start___param,
754 __stop___param - __start___param,
755 level, level,
756 &repair_env_string);
757
758 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
759 do_one_initcall(*fn);
760}
761
762static void __init do_initcalls(void)
763{
764 int level;
765
766 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
767 do_initcall_level(level);
768}
769
770/*
771 * Ok, the machine is now initialized. None of the devices
772 * have been touched yet, but the CPU subsystem is up and
773 * running, and memory and process management works.
774 *
775 * Now we can finally start doing some real work..
776 */
777static void __init do_basic_setup(void)
778{
779 cpuset_init_smp();
780 usermodehelper_init();
781 shmem_init();
782 driver_init();
783 init_irq_proc();
784 do_ctors();
785 usermodehelper_enable();
786 do_initcalls();
787}
788
789static void __init do_pre_smp_initcalls(void)
790{
791 initcall_t *fn;
792
793 for (fn = __initcall_start; fn < __initcall0_start; fn++)
794 do_one_initcall(*fn);
795}
796
797static int run_init_process(const char *init_filename)
798{
799 argv_init[0] = init_filename;
800 return kernel_execve(init_filename, argv_init, envp_init);
801}
802
803static void __init kernel_init_freeable(void);
804
805static int __ref kernel_init(void *unused)
806{
807 kernel_init_freeable();
808 /* need to finish all async __init code before freeing the memory */
809 async_synchronize_full();
810 free_initmem();
811 mark_rodata_ro();
812 system_state = SYSTEM_RUNNING;
813 numa_default_policy();
814
815 current->signal->flags |= SIGNAL_UNKILLABLE;
816 flush_delayed_fput();
817
818 if (ramdisk_execute_command) {
819 if (!run_init_process(ramdisk_execute_command))
820 return 0;
821 printk(KERN_WARNING "Failed to execute %s\n",
822 ramdisk_execute_command);
823 }
824
825 /*
826 * We try each of these until one succeeds.
827 *
828 * The Bourne shell can be used instead of init if we are
829 * trying to recover a really broken machine.
830 */
831 if (execute_command) {
832 if (!run_init_process(execute_command))
833 return 0;
834 printk(KERN_WARNING "Failed to execute %s. Attempting "
835 "defaults...\n", execute_command);
836 }
837 if (!run_init_process("/sbin/init") ||
838 !run_init_process("/etc/init") ||
839 !run_init_process("/bin/init") ||
840 !run_init_process("/bin/sh"))
841 return 0;
842
843 panic("No init found. Try passing init= option to kernel. "
844 "See Linux Documentation/init.txt for guidance.");
845}
846
847static void __init kernel_init_freeable(void)
848{
849 /*
850 * Wait until kthreadd is all set-up.
851 */
852 wait_for_completion(&kthreadd_done);
853
854 /* Now the scheduler is fully set up and can do blocking allocations */
855 gfp_allowed_mask = __GFP_BITS_MASK;
856
857 /*
858 * init can allocate pages on any node
859 */
860 set_mems_allowed(node_states[N_HIGH_MEMORY]);
861 /*
862 * init can run on any cpu.
863 */
864 set_cpus_allowed_ptr(current, cpu_all_mask);
865
866 cad_pid = task_pid(current);
867
868 smp_prepare_cpus(setup_max_cpus);
869
870 do_pre_smp_initcalls();
871 lockup_detector_init();
872
873 smp_init();
874 sched_init_smp();
875
876 do_basic_setup();
877
878 /* Open the /dev/console on the rootfs, this should never fail */
879 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
880 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
881
882 (void) sys_dup(0);
883 (void) sys_dup(0);
884 /*
885 * check if there is an early userspace init. If yes, let it do all
886 * the work
887 */
888
889 if (!ramdisk_execute_command)
890 ramdisk_execute_command = "/init";
891
892 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
893 ramdisk_execute_command = NULL;
894 prepare_namespace();
895 }
896
897 /*
898 * Ok, we have completed the initial bootup, and
899 * we're essentially up and running. Get rid of the
900 * initmem segments and start the user-mode stuff..
901 */
902}