agp/intel: remove restore in resume
[linux-2.6/mini2440.git] / init / main.c
blob303903cf243fba4ee11921f0920601129815e250
1 /*
2 * linux/init/main.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
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>
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/tty.h>
28 #include <linux/gfp.h>
29 #include <linux/percpu.h>
30 #include <linux/kmod.h>
31 #include <linux/vmalloc.h>
32 #include <linux/kernel_stat.h>
33 #include <linux/start_kernel.h>
34 #include <linux/security.h>
35 #include <linux/smp.h>
36 #include <linux/workqueue.h>
37 #include <linux/profile.h>
38 #include <linux/rcupdate.h>
39 #include <linux/moduleparam.h>
40 #include <linux/kallsyms.h>
41 #include <linux/writeback.h>
42 #include <linux/cpu.h>
43 #include <linux/cpuset.h>
44 #include <linux/cgroup.h>
45 #include <linux/efi.h>
46 #include <linux/tick.h>
47 #include <linux/interrupt.h>
48 #include <linux/taskstats_kern.h>
49 #include <linux/delayacct.h>
50 #include <linux/unistd.h>
51 #include <linux/rmap.h>
52 #include <linux/mempolicy.h>
53 #include <linux/key.h>
54 #include <linux/buffer_head.h>
55 #include <linux/page_cgroup.h>
56 #include <linux/debug_locks.h>
57 #include <linux/debugobjects.h>
58 #include <linux/lockdep.h>
59 #include <linux/pid_namespace.h>
60 #include <linux/device.h>
61 #include <linux/kthread.h>
62 #include <linux/sched.h>
63 #include <linux/signal.h>
64 #include <linux/idr.h>
65 #include <linux/ftrace.h>
66 #include <linux/async.h>
67 #include <trace/boot.h>
69 #include <asm/io.h>
70 #include <asm/bugs.h>
71 #include <asm/setup.h>
72 #include <asm/sections.h>
73 #include <asm/cacheflush.h>
74 #include <trace/kmemtrace.h>
76 #ifdef CONFIG_X86_LOCAL_APIC
77 #include <asm/smp.h>
78 #endif
80 static int kernel_init(void *);
82 extern void init_IRQ(void);
83 extern void fork_init(unsigned long);
84 extern void mca_init(void);
85 extern void sbus_init(void);
86 extern void prio_tree_init(void);
87 extern void radix_tree_init(void);
88 extern void free_initmem(void);
89 #ifdef CONFIG_ACPI
90 extern void acpi_early_init(void);
91 #else
92 static inline void acpi_early_init(void) { }
93 #endif
94 #ifndef CONFIG_DEBUG_RODATA
95 static inline void mark_rodata_ro(void) { }
96 #endif
98 #ifdef CONFIG_TC
99 extern void tc_init(void);
100 #endif
102 enum system_states system_state __read_mostly;
103 EXPORT_SYMBOL(system_state);
106 * Boot command-line arguments
108 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
109 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
111 extern void time_init(void);
112 /* Default late time init is NULL. archs can override this later. */
113 void (*__initdata late_time_init)(void);
114 extern void softirq_init(void);
116 /* Untouched command line saved by arch-specific code. */
117 char __initdata boot_command_line[COMMAND_LINE_SIZE];
118 /* Untouched saved command line (eg. for /proc) */
119 char *saved_command_line;
120 /* Command line for parameter parsing */
121 static char *static_command_line;
123 static char *execute_command;
124 static char *ramdisk_execute_command;
126 #ifdef CONFIG_SMP
127 /* Setup configured maximum number of CPUs to activate */
128 unsigned int __initdata setup_max_cpus = NR_CPUS;
131 * Setup routine for controlling SMP activation
133 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
134 * activation entirely (the MPS table probe still happens, though).
136 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
137 * greater than 0, limits the maximum number of CPUs activated in
138 * SMP mode to <NUM>.
141 void __weak arch_disable_smp_support(void) { }
143 static int __init nosmp(char *str)
145 setup_max_cpus = 0;
146 arch_disable_smp_support();
148 return 0;
151 early_param("nosmp", nosmp);
153 static int __init maxcpus(char *str)
155 get_option(&str, &setup_max_cpus);
156 if (setup_max_cpus == 0)
157 arch_disable_smp_support();
159 return 0;
162 early_param("maxcpus", maxcpus);
163 #else
164 const unsigned int setup_max_cpus = NR_CPUS;
165 #endif
168 * If set, this is an indication to the drivers that reset the underlying
169 * device before going ahead with the initialization otherwise driver might
170 * rely on the BIOS and skip the reset operation.
172 * This is useful if kernel is booting in an unreliable environment.
173 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
174 * skipped and devices will be in unknown state.
176 unsigned int reset_devices;
177 EXPORT_SYMBOL(reset_devices);
179 static int __init set_reset_devices(char *str)
181 reset_devices = 1;
182 return 1;
185 __setup("reset_devices", set_reset_devices);
187 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
188 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
189 static const char *panic_later, *panic_param;
191 extern struct obs_kernel_param __setup_start[], __setup_end[];
193 static int __init obsolete_checksetup(char *line)
195 struct obs_kernel_param *p;
196 int had_early_param = 0;
198 p = __setup_start;
199 do {
200 int n = strlen(p->str);
201 if (!strncmp(line, p->str, n)) {
202 if (p->early) {
203 /* Already done in parse_early_param?
204 * (Needs exact match on param part).
205 * Keep iterating, as we can have early
206 * params and __setups of same names 8( */
207 if (line[n] == '\0' || line[n] == '=')
208 had_early_param = 1;
209 } else if (!p->setup_func) {
210 printk(KERN_WARNING "Parameter %s is obsolete,"
211 " ignored\n", p->str);
212 return 1;
213 } else if (p->setup_func(line + n))
214 return 1;
216 p++;
217 } while (p < __setup_end);
219 return had_early_param;
223 * This should be approx 2 Bo*oMips to start (note initial shift), and will
224 * still work even if initially too large, it will just take slightly longer
226 unsigned long loops_per_jiffy = (1<<12);
228 EXPORT_SYMBOL(loops_per_jiffy);
230 static int __init debug_kernel(char *str)
232 console_loglevel = 10;
233 return 0;
236 static int __init quiet_kernel(char *str)
238 console_loglevel = 4;
239 return 0;
242 early_param("debug", debug_kernel);
243 early_param("quiet", quiet_kernel);
245 static int __init loglevel(char *str)
247 get_option(&str, &console_loglevel);
248 return 0;
251 early_param("loglevel", loglevel);
254 * Unknown boot options get handed to init, unless they look like
255 * failed parameters
257 static int __init unknown_bootoption(char *param, char *val)
259 /* Change NUL term back to "=", to make "param" the whole string. */
260 if (val) {
261 /* param=val or param="val"? */
262 if (val == param+strlen(param)+1)
263 val[-1] = '=';
264 else if (val == param+strlen(param)+2) {
265 val[-2] = '=';
266 memmove(val-1, val, strlen(val)+1);
267 val--;
268 } else
269 BUG();
272 /* Handle obsolete-style parameters */
273 if (obsolete_checksetup(param))
274 return 0;
277 * Preemptive maintenance for "why didn't my misspelled command
278 * line work?"
280 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
281 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
282 return 0;
285 if (panic_later)
286 return 0;
288 if (val) {
289 /* Environment option */
290 unsigned int i;
291 for (i = 0; envp_init[i]; i++) {
292 if (i == MAX_INIT_ENVS) {
293 panic_later = "Too many boot env vars at `%s'";
294 panic_param = param;
296 if (!strncmp(param, envp_init[i], val - param))
297 break;
299 envp_init[i] = param;
300 } else {
301 /* Command line option */
302 unsigned int i;
303 for (i = 0; argv_init[i]; i++) {
304 if (i == MAX_INIT_ARGS) {
305 panic_later = "Too many boot init vars at `%s'";
306 panic_param = param;
309 argv_init[i] = param;
311 return 0;
314 #ifdef CONFIG_DEBUG_PAGEALLOC
315 int __read_mostly debug_pagealloc_enabled = 0;
316 #endif
318 static int __init init_setup(char *str)
320 unsigned int i;
322 execute_command = str;
324 * In case LILO is going to boot us with default command line,
325 * it prepends "auto" before the whole cmdline which makes
326 * the shell think it should execute a script with such name.
327 * So we ignore all arguments entered _before_ init=... [MJ]
329 for (i = 1; i < MAX_INIT_ARGS; i++)
330 argv_init[i] = NULL;
331 return 1;
333 __setup("init=", init_setup);
335 static int __init rdinit_setup(char *str)
337 unsigned int i;
339 ramdisk_execute_command = str;
340 /* See "auto" comment in init_setup */
341 for (i = 1; i < MAX_INIT_ARGS; i++)
342 argv_init[i] = NULL;
343 return 1;
345 __setup("rdinit=", rdinit_setup);
347 #ifndef CONFIG_SMP
349 #ifdef CONFIG_X86_LOCAL_APIC
350 static void __init smp_init(void)
352 APIC_init_uniprocessor();
354 #else
355 #define smp_init() do { } while (0)
356 #endif
358 static inline void setup_per_cpu_areas(void) { }
359 static inline void setup_nr_cpu_ids(void) { }
360 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
362 #else
364 #if NR_CPUS > BITS_PER_LONG
365 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
366 EXPORT_SYMBOL(cpu_mask_all);
367 #endif
369 /* Setup number of possible processor ids */
370 int nr_cpu_ids __read_mostly = NR_CPUS;
371 EXPORT_SYMBOL(nr_cpu_ids);
373 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
374 static void __init setup_nr_cpu_ids(void)
376 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
379 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
380 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
382 EXPORT_SYMBOL(__per_cpu_offset);
384 static void __init setup_per_cpu_areas(void)
386 unsigned long size, i;
387 char *ptr;
388 unsigned long nr_possible_cpus = num_possible_cpus();
390 /* Copy section for each CPU (we discard the original) */
391 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
392 ptr = alloc_bootmem_pages(size * nr_possible_cpus);
394 for_each_possible_cpu(i) {
395 __per_cpu_offset[i] = ptr - __per_cpu_start;
396 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
397 ptr += size;
400 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
402 /* Called by boot processor to activate the rest. */
403 static void __init smp_init(void)
405 unsigned int cpu;
408 * Set up the current CPU as possible to migrate to.
409 * The other ones will be done by cpu_up/cpu_down()
411 set_cpu_active(smp_processor_id(), true);
413 /* FIXME: This should be done in userspace --RR */
414 for_each_present_cpu(cpu) {
415 if (num_online_cpus() >= setup_max_cpus)
416 break;
417 if (!cpu_online(cpu))
418 cpu_up(cpu);
421 /* Any cleanup work */
422 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
423 smp_cpus_done(setup_max_cpus);
426 #endif
429 * We need to store the untouched command line for future reference.
430 * We also need to store the touched command line since the parameter
431 * parsing is performed in place, and we should allow a component to
432 * store reference of name/value for future reference.
434 static void __init setup_command_line(char *command_line)
436 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
437 static_command_line = alloc_bootmem(strlen (command_line)+1);
438 strcpy (saved_command_line, boot_command_line);
439 strcpy (static_command_line, command_line);
443 * We need to finalize in a non-__init function or else race conditions
444 * between the root thread and the init thread may cause start_kernel to
445 * be reaped by free_initmem before the root thread has proceeded to
446 * cpu_idle.
448 * gcc-3.4 accidentally inlines this function, so use noinline.
451 static noinline void __init_refok rest_init(void)
452 __releases(kernel_lock)
454 int pid;
456 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
457 numa_default_policy();
458 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
459 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
460 unlock_kernel();
463 * The boot idle thread must execute schedule()
464 * at least once to get things moving:
466 init_idle_bootup_task(current);
467 rcu_scheduler_starting();
468 preempt_enable_no_resched();
469 schedule();
470 preempt_disable();
472 /* Call into cpu_idle with preempt disabled */
473 cpu_idle();
476 /* Check for early params. */
477 static int __init do_early_param(char *param, char *val)
479 struct obs_kernel_param *p;
481 for (p = __setup_start; p < __setup_end; p++) {
482 if ((p->early && strcmp(param, p->str) == 0) ||
483 (strcmp(param, "console") == 0 &&
484 strcmp(p->str, "earlycon") == 0)
486 if (p->setup_func(val) != 0)
487 printk(KERN_WARNING
488 "Malformed early option '%s'\n", param);
491 /* We accept everything at this stage. */
492 return 0;
495 void __init parse_early_options(char *cmdline)
497 parse_args("early options", cmdline, NULL, 0, do_early_param);
500 /* Arch code calls this early on, or if not, just before other parsing. */
501 void __init parse_early_param(void)
503 static __initdata int done = 0;
504 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
506 if (done)
507 return;
509 /* All fall through to do_early_param. */
510 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
511 parse_early_options(tmp_cmdline);
512 done = 1;
516 * Activate the first processor.
519 static void __init boot_cpu_init(void)
521 int cpu = smp_processor_id();
522 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
523 set_cpu_online(cpu, true);
524 set_cpu_present(cpu, true);
525 set_cpu_possible(cpu, true);
528 void __init __weak smp_setup_processor_id(void)
532 void __init __weak thread_info_cache_init(void)
536 asmlinkage void __init start_kernel(void)
538 char * command_line;
539 extern struct kernel_param __start___param[], __stop___param[];
541 smp_setup_processor_id();
544 * Need to run as early as possible, to initialize the
545 * lockdep hash:
547 lockdep_init();
548 debug_objects_early_init();
551 * Set up the the initial canary ASAP:
553 boot_init_stack_canary();
555 cgroup_init_early();
557 local_irq_disable();
558 early_boot_irqs_off();
559 early_init_irq_lock_class();
562 * Interrupts are still disabled. Do necessary setups, then
563 * enable them
565 lock_kernel();
566 tick_init();
567 boot_cpu_init();
568 page_address_init();
569 printk(KERN_NOTICE "%s", linux_banner);
570 setup_arch(&command_line);
571 mm_init_owner(&init_mm, &init_task);
572 setup_command_line(command_line);
573 setup_per_cpu_areas();
574 setup_nr_cpu_ids();
575 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
578 * Set up the scheduler prior starting any interrupts (such as the
579 * timer interrupt). Full topology setup happens at smp_init()
580 * time - but meanwhile we still have a functioning scheduler.
582 sched_init();
584 * Disable preemption - early bootup scheduling is extremely
585 * fragile until we cpu_idle() for the first time.
587 preempt_disable();
588 build_all_zonelists();
589 page_alloc_init();
590 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
591 parse_early_param();
592 parse_args("Booting kernel", static_command_line, __start___param,
593 __stop___param - __start___param,
594 &unknown_bootoption);
595 if (!irqs_disabled()) {
596 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
597 "enabled *very* early, fixing it\n");
598 local_irq_disable();
600 sort_main_extable();
601 trap_init();
602 rcu_init();
603 /* init some links before init_ISA_irqs() */
604 early_irq_init();
605 init_IRQ();
606 pidhash_init();
607 init_timers();
608 hrtimers_init();
609 softirq_init();
610 timekeeping_init();
611 time_init();
612 sched_clock_init();
613 profile_init();
614 if (!irqs_disabled())
615 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
616 "enabled early\n");
617 early_boot_irqs_on();
618 local_irq_enable();
621 * HACK ALERT! This is early. We're enabling the console before
622 * we've done PCI setups etc, and console_init() must be aware of
623 * this. But we do want output early, in case something goes wrong.
625 console_init();
626 if (panic_later)
627 panic(panic_later, panic_param);
629 lockdep_info();
632 * Need to run this when irqs are enabled, because it wants
633 * to self-test [hard/soft]-irqs on/off lock inversion bugs
634 * too:
636 locking_selftest();
638 #ifdef CONFIG_BLK_DEV_INITRD
639 if (initrd_start && !initrd_below_start_ok &&
640 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
641 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
642 "disabling it.\n",
643 page_to_pfn(virt_to_page((void *)initrd_start)),
644 min_low_pfn);
645 initrd_start = 0;
647 #endif
648 vmalloc_init();
649 vfs_caches_init_early();
650 cpuset_init_early();
651 page_cgroup_init();
652 mem_init();
653 enable_debug_pagealloc();
654 cpu_hotplug_init();
655 kmem_cache_init();
656 kmemtrace_init();
657 debug_objects_mem_init();
658 idr_init_cache();
659 setup_per_cpu_pageset();
660 numa_policy_init();
661 if (late_time_init)
662 late_time_init();
663 calibrate_delay();
664 pidmap_init();
665 pgtable_cache_init();
666 prio_tree_init();
667 anon_vma_init();
668 #ifdef CONFIG_X86
669 if (efi_enabled)
670 efi_enter_virtual_mode();
671 #endif
672 thread_info_cache_init();
673 cred_init();
674 fork_init(num_physpages);
675 proc_caches_init();
676 buffer_init();
677 key_init();
678 security_init();
679 vfs_caches_init(num_physpages);
680 radix_tree_init();
681 signals_init();
682 /* rootfs populating might need page-writeback */
683 page_writeback_init();
684 #ifdef CONFIG_PROC_FS
685 proc_root_init();
686 #endif
687 cgroup_init();
688 cpuset_init();
689 taskstats_init_early();
690 delayacct_init();
692 check_bugs();
694 acpi_early_init(); /* before LAPIC and SMP init */
696 ftrace_init();
698 /* Do the rest non-__init'ed, we're now alive */
699 rest_init();
702 int initcall_debug;
703 core_param(initcall_debug, initcall_debug, bool, 0644);
705 static char msgbuf[64];
706 static struct boot_trace_call call;
707 static struct boot_trace_ret ret;
709 int do_one_initcall(initcall_t fn)
711 int count = preempt_count();
712 ktime_t calltime, delta, rettime;
714 if (initcall_debug) {
715 call.caller = task_pid_nr(current);
716 printk("calling %pF @ %i\n", fn, call.caller);
717 calltime = ktime_get();
718 trace_boot_call(&call, fn);
719 enable_boot_trace();
722 ret.result = fn();
724 if (initcall_debug) {
725 disable_boot_trace();
726 rettime = ktime_get();
727 delta = ktime_sub(rettime, calltime);
728 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
729 trace_boot_ret(&ret, fn);
730 printk("initcall %pF returned %d after %Ld usecs\n", fn,
731 ret.result, ret.duration);
734 msgbuf[0] = 0;
736 if (ret.result && ret.result != -ENODEV && initcall_debug)
737 sprintf(msgbuf, "error code %d ", ret.result);
739 if (preempt_count() != count) {
740 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
741 preempt_count() = count;
743 if (irqs_disabled()) {
744 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
745 local_irq_enable();
747 if (msgbuf[0]) {
748 printk("initcall %pF returned with %s\n", fn, msgbuf);
751 return ret.result;
755 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
757 static void __init do_initcalls(void)
759 initcall_t *call;
761 for (call = __early_initcall_end; call < __initcall_end; call++)
762 do_one_initcall(*call);
764 /* Make sure there is no pending stuff from the initcall sequence */
765 flush_scheduled_work();
769 * Ok, the machine is now initialized. None of the devices
770 * have been touched yet, but the CPU subsystem is up and
771 * running, and memory and process management works.
773 * Now we can finally start doing some real work..
775 static void __init do_basic_setup(void)
777 rcu_init_sched(); /* needed by module_init stage. */
778 init_workqueues();
779 cpuset_init_smp();
780 usermodehelper_init();
781 driver_init();
782 init_irq_proc();
783 do_initcalls();
786 static void __init do_pre_smp_initcalls(void)
788 initcall_t *call;
790 for (call = __initcall_start; call < __early_initcall_end; call++)
791 do_one_initcall(*call);
794 static void run_init_process(char *init_filename)
796 argv_init[0] = init_filename;
797 kernel_execve(init_filename, argv_init, envp_init);
800 /* This is a non __init function. Force it to be noinline otherwise gcc
801 * makes it inline to init() and it becomes part of init.text section
803 static noinline int init_post(void)
804 __releases(kernel_lock)
806 /* need to finish all async __init code before freeing the memory */
807 async_synchronize_full();
808 free_initmem();
809 unlock_kernel();
810 mark_rodata_ro();
811 system_state = SYSTEM_RUNNING;
812 numa_default_policy();
814 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
815 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
817 (void) sys_dup(0);
818 (void) sys_dup(0);
820 current->signal->flags |= SIGNAL_UNKILLABLE;
822 if (ramdisk_execute_command) {
823 run_init_process(ramdisk_execute_command);
824 printk(KERN_WARNING "Failed to execute %s\n",
825 ramdisk_execute_command);
829 * We try each of these until one succeeds.
831 * The Bourne shell can be used instead of init if we are
832 * trying to recover a really broken machine.
834 if (execute_command) {
835 run_init_process(execute_command);
836 printk(KERN_WARNING "Failed to execute %s. Attempting "
837 "defaults...\n", execute_command);
839 run_init_process("/sbin/init");
840 run_init_process("/etc/init");
841 run_init_process("/bin/init");
842 run_init_process("/bin/sh");
844 panic("No init found. Try passing init= option to kernel.");
847 static int __init kernel_init(void * unused)
849 lock_kernel();
851 * init can run on any cpu.
853 set_cpus_allowed_ptr(current, cpu_all_mask);
855 * Tell the world that we're going to be the grim
856 * reaper of innocent orphaned children.
858 * We don't want people to have to make incorrect
859 * assumptions about where in the task array this
860 * can be found.
862 init_pid_ns.child_reaper = current;
864 cad_pid = task_pid(current);
866 smp_prepare_cpus(setup_max_cpus);
868 do_pre_smp_initcalls();
869 start_boot_trace();
871 smp_init();
872 sched_init_smp();
874 do_basic_setup();
877 * check if there is an early userspace init. If yes, let it do all
878 * the work
881 if (!ramdisk_execute_command)
882 ramdisk_execute_command = "/init";
884 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
885 ramdisk_execute_command = NULL;
886 prepare_namespace();
890 * Ok, we have completed the initial bootup, and
891 * we're essentially up and running. Get rid of the
892 * initmem segments and start the user-mode stuff..
895 init_post();
896 return 0;