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1da177e4
LT
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
1da177e4
LT
12#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/proc_fs.h>
1da177e4
LT
15#include <linux/kernel.h>
16#include <linux/syscalls.h>
17#include <linux/string.h>
18#include <linux/ctype.h>
19#include <linux/delay.h>
20#include <linux/utsname.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/hdreg.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/kernel_stat.h>
d7cd5611 32#include <linux/start_kernel.h>
1da177e4
LT
33#include <linux/security.h>
34#include <linux/workqueue.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/efi.h>
906568c9 43#include <linux/tick.h>
6168a702 44#include <linux/interrupt.h>
c757249a 45#include <linux/taskstats_kern.h>
ca74e92b 46#include <linux/delayacct.h>
1da177e4
LT
47#include <linux/unistd.h>
48#include <linux/rmap.h>
49#include <linux/mempolicy.h>
50#include <linux/key.h>
4552d5dc 51#include <linux/unwind.h>
b6cd0b77 52#include <linux/buffer_head.h>
9a11b49a 53#include <linux/debug_locks.h>
fbb9ce95 54#include <linux/lockdep.h>
84d73786 55#include <linux/pid_namespace.h>
1f21782e 56#include <linux/device.h>
73c27992 57#include <linux/kthread.h>
1da177e4
LT
58
59#include <asm/io.h>
60#include <asm/bugs.h>
61#include <asm/setup.h>
a940199f 62#include <asm/sections.h>
37b73c82 63#include <asm/cacheflush.h>
1da177e4 64
1da177e4
LT
65#ifdef CONFIG_X86_LOCAL_APIC
66#include <asm/smp.h>
67#endif
68
69/*
69c99ac1
CQH
70 * This is one of the first .c files built. Error out early if we have compiler
71 * trouble.
72 *
73 * Versions of gcc older than that listed below may actually compile and link
74 * okay, but the end product can have subtle run time bugs. To avoid associated
75 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
76 * too old from the very beginning.
1da177e4 77 */
fd285bb5 78#if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
1da177e4
LT
79#error Sorry, your GCC is too old. It builds incorrect kernels.
80#endif
81
f1a60dbf
AM
82#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
83#warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended.
84#endif
85
aae5f662 86static int kernel_init(void *);
1da177e4
LT
87
88extern void init_IRQ(void);
1da177e4
LT
89extern void fork_init(unsigned long);
90extern void mca_init(void);
91extern void sbus_init(void);
1da177e4 92extern void signals_init(void);
1da177e4
LT
93extern void pidhash_init(void);
94extern void pidmap_init(void);
95extern void prio_tree_init(void);
96extern void radix_tree_init(void);
97extern void free_initmem(void);
1da177e4
LT
98#ifdef CONFIG_ACPI
99extern void acpi_early_init(void);
100#else
101static inline void acpi_early_init(void) { }
102#endif
37b73c82
AV
103#ifndef CONFIG_DEBUG_RODATA
104static inline void mark_rodata_ro(void) { }
105#endif
1da177e4
LT
106
107#ifdef CONFIG_TC
108extern void tc_init(void);
109#endif
110
111enum system_states system_state;
112EXPORT_SYMBOL(system_state);
113
114/*
115 * Boot command-line arguments
116 */
117#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
118#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
119
120extern void time_init(void);
121/* Default late time init is NULL. archs can override this later. */
122void (*late_time_init)(void);
123extern void softirq_init(void);
124
30d7e0d4
ABL
125/* Untouched command line saved by arch-specific code. */
126char __initdata boot_command_line[COMMAND_LINE_SIZE];
127/* Untouched saved command line (eg. for /proc) */
128char *saved_command_line;
129/* Command line for parameter parsing */
130static char *static_command_line;
1da177e4
LT
131
132static char *execute_command;
ffdfc409 133static char *ramdisk_execute_command;
1da177e4
LT
134
135/* Setup configured maximum number of CPUs to activate */
136static unsigned int max_cpus = NR_CPUS;
137
7e96287d
VG
138/*
139 * If set, this is an indication to the drivers that reset the underlying
140 * device before going ahead with the initialization otherwise driver might
141 * rely on the BIOS and skip the reset operation.
142 *
143 * This is useful if kernel is booting in an unreliable environment.
144 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
145 * skipped and devices will be in unknown state.
146 */
147unsigned int reset_devices;
148EXPORT_SYMBOL(reset_devices);
149
1da177e4
LT
150/*
151 * Setup routine for controlling SMP activation
152 *
153 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
154 * activation entirely (the MPS table probe still happens, though).
155 *
156 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
157 * greater than 0, limits the maximum number of CPUs activated in
158 * SMP mode to <NUM>.
159 */
160static int __init nosmp(char *str)
161{
162 max_cpus = 0;
163 return 1;
164}
165
166__setup("nosmp", nosmp);
167
168static int __init maxcpus(char *str)
169{
170 get_option(&str, &max_cpus);
171 return 1;
172}
173
174__setup("maxcpus=", maxcpus);
175
7e96287d
VG
176static int __init set_reset_devices(char *str)
177{
178 reset_devices = 1;
179 return 1;
180}
181
182__setup("reset_devices", set_reset_devices);
183
1da177e4
LT
184static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
185char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
186static const char *panic_later, *panic_param;
187
188extern struct obs_kernel_param __setup_start[], __setup_end[];
189
190static int __init obsolete_checksetup(char *line)
191{
192 struct obs_kernel_param *p;
33df0d19 193 int had_early_param = 0;
1da177e4
LT
194
195 p = __setup_start;
196 do {
197 int n = strlen(p->str);
198 if (!strncmp(line, p->str, n)) {
199 if (p->early) {
33df0d19
RR
200 /* Already done in parse_early_param?
201 * (Needs exact match on param part).
202 * Keep iterating, as we can have early
203 * params and __setups of same names 8( */
1da177e4 204 if (line[n] == '\0' || line[n] == '=')
33df0d19 205 had_early_param = 1;
1da177e4
LT
206 } else if (!p->setup_func) {
207 printk(KERN_WARNING "Parameter %s is obsolete,"
208 " ignored\n", p->str);
209 return 1;
210 } else if (p->setup_func(line + n))
211 return 1;
212 }
213 p++;
214 } while (p < __setup_end);
33df0d19
RR
215
216 return had_early_param;
1da177e4
LT
217}
218
219/*
220 * This should be approx 2 Bo*oMips to start (note initial shift), and will
221 * still work even if initially too large, it will just take slightly longer
222 */
223unsigned long loops_per_jiffy = (1<<12);
224
225EXPORT_SYMBOL(loops_per_jiffy);
226
227static int __init debug_kernel(char *str)
228{
229 if (*str)
230 return 0;
231 console_loglevel = 10;
232 return 1;
233}
234
235static int __init quiet_kernel(char *str)
236{
237 if (*str)
238 return 0;
239 console_loglevel = 4;
240 return 1;
241}
242
243__setup("debug", debug_kernel);
244__setup("quiet", quiet_kernel);
245
246static int __init loglevel(char *str)
247{
248 get_option(&str, &console_loglevel);
249 return 1;
250}
251
252__setup("loglevel=", loglevel);
253
254/*
255 * Unknown boot options get handed to init, unless they look like
256 * failed parameters
257 */
258static int __init unknown_bootoption(char *param, char *val)
259{
260 /* Change NUL term back to "=", to make "param" the whole string. */
261 if (val) {
262 /* param=val or param="val"? */
263 if (val == param+strlen(param)+1)
264 val[-1] = '=';
265 else if (val == param+strlen(param)+2) {
266 val[-2] = '=';
267 memmove(val-1, val, strlen(val)+1);
268 val--;
269 } else
270 BUG();
271 }
272
273 /* Handle obsolete-style parameters */
274 if (obsolete_checksetup(param))
275 return 0;
276
277 /*
278 * Preemptive maintenance for "why didn't my mispelled command
279 * line work?"
280 */
281 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
282 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
283 return 0;
284 }
285
286 if (panic_later)
287 return 0;
288
289 if (val) {
290 /* Environment option */
291 unsigned int i;
292 for (i = 0; envp_init[i]; i++) {
293 if (i == MAX_INIT_ENVS) {
294 panic_later = "Too many boot env vars at `%s'";
295 panic_param = param;
296 }
297 if (!strncmp(param, envp_init[i], val - param))
298 break;
299 }
300 envp_init[i] = param;
301 } else {
302 /* Command line option */
303 unsigned int i;
304 for (i = 0; argv_init[i]; i++) {
305 if (i == MAX_INIT_ARGS) {
306 panic_later = "Too many boot init vars at `%s'";
307 panic_param = param;
308 }
309 }
310 argv_init[i] = param;
311 }
312 return 0;
313}
314
315static int __init init_setup(char *str)
316{
317 unsigned int i;
318
319 execute_command = str;
320 /*
321 * In case LILO is going to boot us with default command line,
322 * it prepends "auto" before the whole cmdline which makes
323 * the shell think it should execute a script with such name.
324 * So we ignore all arguments entered _before_ init=... [MJ]
325 */
326 for (i = 1; i < MAX_INIT_ARGS; i++)
327 argv_init[i] = NULL;
328 return 1;
329}
330__setup("init=", init_setup);
331
ffdfc409
OJ
332static int __init rdinit_setup(char *str)
333{
334 unsigned int i;
335
336 ramdisk_execute_command = str;
337 /* See "auto" comment in init_setup */
338 for (i = 1; i < MAX_INIT_ARGS; i++)
339 argv_init[i] = NULL;
340 return 1;
341}
342__setup("rdinit=", rdinit_setup);
343
1da177e4
LT
344#ifndef CONFIG_SMP
345
346#ifdef CONFIG_X86_LOCAL_APIC
347static void __init smp_init(void)
348{
349 APIC_init_uniprocessor();
350}
351#else
352#define smp_init() do { } while (0)
353#endif
354
355static inline void setup_per_cpu_areas(void) { }
356static inline void smp_prepare_cpus(unsigned int maxcpus) { }
357
358#else
359
360#ifdef __GENERIC_PER_CPU
b73b459f 361unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
1da177e4
LT
362
363EXPORT_SYMBOL(__per_cpu_offset);
364
365static void __init setup_per_cpu_areas(void)
366{
367 unsigned long size, i;
368 char *ptr;
63872f87 369 unsigned long nr_possible_cpus = num_possible_cpus();
1da177e4
LT
370
371 /* Copy section for each CPU (we discard the original) */
b6e3590f
JF
372 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
373 ptr = alloc_bootmem_pages(size * nr_possible_cpus);
1da177e4 374
0a945022 375 for_each_possible_cpu(i) {
1da177e4
LT
376 __per_cpu_offset[i] = ptr - __per_cpu_start;
377 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
63872f87 378 ptr += size;
1da177e4
LT
379 }
380}
381#endif /* !__GENERIC_PER_CPU */
382
383/* Called by boot processor to activate the rest. */
384static void __init smp_init(void)
385{
53b8a315 386 unsigned int cpu;
1da177e4
LT
387
388 /* FIXME: This should be done in userspace --RR */
53b8a315 389 for_each_present_cpu(cpu) {
1da177e4
LT
390 if (num_online_cpus() >= max_cpus)
391 break;
53b8a315
CL
392 if (!cpu_online(cpu))
393 cpu_up(cpu);
1da177e4
LT
394 }
395
396 /* Any cleanup work */
397 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
398 smp_cpus_done(max_cpus);
1da177e4
LT
399}
400
401#endif
402
30d7e0d4
ABL
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 */
409static 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
1da177e4
LT
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
92080309 426static void noinline __init_refok rest_init(void)
1da177e4
LT
427 __releases(kernel_lock)
428{
73c27992
EB
429 int pid;
430
aae5f662 431 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
1da177e4 432 numa_default_policy();
73c27992
EB
433 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
434 kthreadd_task = find_task_by_pid(pid);
1da177e4 435 unlock_kernel();
f340c0d1
IM
436
437 /*
438 * The boot idle thread must execute schedule()
1df21055 439 * at least once to get things moving:
f340c0d1 440 */
1df21055 441 init_idle_bootup_task(current);
5bfb5d69 442 preempt_enable_no_resched();
f340c0d1 443 schedule();
5bfb5d69 444 preempt_disable();
f340c0d1 445
5bfb5d69 446 /* Call into cpu_idle with preempt disabled */
1da177e4 447 cpu_idle();
1df21055 448}
1da177e4
LT
449
450/* Check for early params. */
451static int __init do_early_param(char *param, char *val)
452{
453 struct obs_kernel_param *p;
454
455 for (p = __setup_start; p < __setup_end; p++) {
456 if (p->early && strcmp(param, p->str) == 0) {
457 if (p->setup_func(val) != 0)
458 printk(KERN_WARNING
459 "Malformed early option '%s'\n", param);
460 }
461 }
462 /* We accept everything at this stage. */
463 return 0;
464}
465
466/* Arch code calls this early on, or if not, just before other parsing. */
467void __init parse_early_param(void)
468{
469 static __initdata int done = 0;
470 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
471
472 if (done)
473 return;
474
475 /* All fall through to do_early_param. */
30d7e0d4 476 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
1da177e4
LT
477 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
478 done = 1;
479}
480
481/*
482 * Activate the first processor.
483 */
484
44fd2299
SS
485static void __init boot_cpu_init(void)
486{
487 int cpu = smp_processor_id();
488 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
489 cpu_set(cpu, cpu_online_map);
490 cpu_set(cpu, cpu_present_map);
491 cpu_set(cpu, cpu_possible_map);
492}
493
033ab7f8
AM
494void __init __attribute__((weak)) smp_setup_processor_id(void)
495{
496}
497
1da177e4
LT
498asmlinkage void __init start_kernel(void)
499{
500 char * command_line;
501 extern struct kernel_param __start___param[], __stop___param[];
033ab7f8
AM
502
503 smp_setup_processor_id();
504
fbb9ce95
IM
505 /*
506 * Need to run as early as possible, to initialize the
507 * lockdep hash:
508 */
c9538ed4 509 unwind_init();
fbb9ce95
IM
510 lockdep_init();
511
512 local_irq_disable();
513 early_boot_irqs_off();
243c7621 514 early_init_irq_lock_class();
fbb9ce95 515
1da177e4
LT
516/*
517 * Interrupts are still disabled. Do necessary setups, then
518 * enable them
519 */
520 lock_kernel();
906568c9 521 tick_init();
44fd2299 522 boot_cpu_init();
1da177e4
LT
523 page_address_init();
524 printk(KERN_NOTICE);
8993780a 525 printk(linux_banner);
1da177e4 526 setup_arch(&command_line);
30d7e0d4 527 setup_command_line(command_line);
690a973f 528 unwind_setup();
1da177e4 529 setup_per_cpu_areas();
44fd2299 530 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
1da177e4
LT
531
532 /*
533 * Set up the scheduler prior starting any interrupts (such as the
534 * timer interrupt). Full topology setup happens at smp_init()
535 * time - but meanwhile we still have a functioning scheduler.
536 */
537 sched_init();
538 /*
539 * Disable preemption - early bootup scheduling is extremely
540 * fragile until we cpu_idle() for the first time.
541 */
542 preempt_disable();
543 build_all_zonelists();
544 page_alloc_init();
30d7e0d4 545 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
1da177e4 546 parse_early_param();
30d7e0d4 547 parse_args("Booting kernel", static_command_line, __start___param,
1da177e4
LT
548 __stop___param - __start___param,
549 &unknown_bootoption);
c4a68306
AB
550 if (!irqs_disabled()) {
551 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
552 "enabled *very* early, fixing it\n");
553 local_irq_disable();
554 }
1da177e4
LT
555 sort_main_extable();
556 trap_init();
557 rcu_init();
558 init_IRQ();
559 pidhash_init();
560 init_timers();
c0a31329 561 hrtimers_init();
1da177e4 562 softirq_init();
ad596171 563 timekeeping_init();
88fecaa2 564 time_init();
93e02814
HC
565 profile_init();
566 if (!irqs_disabled())
567 printk("start_kernel(): bug: interrupts were enabled early\n");
fbb9ce95 568 early_boot_irqs_on();
93e02814 569 local_irq_enable();
1da177e4
LT
570
571 /*
572 * HACK ALERT! This is early. We're enabling the console before
573 * we've done PCI setups etc, and console_init() must be aware of
574 * this. But we do want output early, in case something goes wrong.
575 */
576 console_init();
577 if (panic_later)
578 panic(panic_later, panic_param);
fbb9ce95
IM
579
580 lockdep_info();
581
9a11b49a
IM
582 /*
583 * Need to run this when irqs are enabled, because it wants
584 * to self-test [hard/soft]-irqs on/off lock inversion bugs
585 * too:
586 */
587 locking_selftest();
588
1da177e4
LT
589#ifdef CONFIG_BLK_DEV_INITRD
590 if (initrd_start && !initrd_below_start_ok &&
591 initrd_start < min_low_pfn << PAGE_SHIFT) {
592 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
593 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
594 initrd_start = 0;
595 }
596#endif
597 vfs_caches_init_early();
c417f024 598 cpuset_init_early();
1da177e4
LT
599 mem_init();
600 kmem_cache_init();
e7c8d5c9 601 setup_per_cpu_pageset();
1da177e4
LT
602 numa_policy_init();
603 if (late_time_init)
604 late_time_init();
605 calibrate_delay();
606 pidmap_init();
607 pgtable_cache_init();
608 prio_tree_init();
609 anon_vma_init();
610#ifdef CONFIG_X86
611 if (efi_enabled)
612 efi_enter_virtual_mode();
613#endif
614 fork_init(num_physpages);
615 proc_caches_init();
616 buffer_init();
617 unnamed_dev_init();
618 key_init();
619 security_init();
620 vfs_caches_init(num_physpages);
621 radix_tree_init();
622 signals_init();
623 /* rootfs populating might need page-writeback */
624 page_writeback_init();
625#ifdef CONFIG_PROC_FS
626 proc_root_init();
627#endif
628 cpuset_init();
c757249a 629 taskstats_init_early();
ca74e92b 630 delayacct_init();
1da177e4
LT
631
632 check_bugs();
633
634 acpi_early_init(); /* before LAPIC and SMP init */
635
636 /* Do the rest non-__init'ed, we're now alive */
637 rest_init();
638}
639
640static int __initdata initcall_debug;
641
642static int __init initcall_debug_setup(char *str)
643{
644 initcall_debug = 1;
645 return 1;
646}
647__setup("initcall_debug", initcall_debug_setup);
648
1da177e4
LT
649extern initcall_t __initcall_start[], __initcall_end[];
650
651static void __init do_initcalls(void)
652{
653 initcall_t *call;
654 int count = preempt_count();
655
656 for (call = __initcall_start; call < __initcall_end; call++) {
8f0c45cd 657 ktime_t t0, t1, delta;
c1cda48a
AM
658 char *msg = NULL;
659 char msgbuf[40];
660 int result;
1da177e4
LT
661
662 if (initcall_debug) {
c1cda48a
AM
663 printk("Calling initcall 0x%p", *call);
664 print_fn_descriptor_symbol(": %s()",
665 (unsigned long) *call);
1da177e4 666 printk("\n");
8f0c45cd 667 t0 = ktime_get();
1da177e4
LT
668 }
669
c1cda48a 670 result = (*call)();
1da177e4 671
8f0c45cd
IM
672 if (initcall_debug) {
673 t1 = ktime_get();
674 delta = ktime_sub(t1, t0);
675
676 printk("initcall 0x%p", *call);
677 print_fn_descriptor_symbol(": %s()",
678 (unsigned long) *call);
679 printk(" returned %d.\n", result);
680
681 printk("initcall 0x%p ran for %Ld msecs: ",
682 *call, (unsigned long long)delta.tv64 >> 20);
683 print_fn_descriptor_symbol("%s()\n",
684 (unsigned long) *call);
685 }
686
f3a19cb4 687 if (result && result != -ENODEV && initcall_debug) {
c1cda48a
AM
688 sprintf(msgbuf, "error code %d", result);
689 msg = msgbuf;
690 }
1da177e4
LT
691 if (preempt_count() != count) {
692 msg = "preemption imbalance";
693 preempt_count() = count;
694 }
695 if (irqs_disabled()) {
696 msg = "disabled interrupts";
697 local_irq_enable();
698 }
699 if (msg) {
c1cda48a
AM
700 printk(KERN_WARNING "initcall at 0x%p", *call);
701 print_fn_descriptor_symbol(": %s()",
702 (unsigned long) *call);
703 printk(": returned with %s\n", msg);
1da177e4
LT
704 }
705 }
706
707 /* Make sure there is no pending stuff from the initcall sequence */
708 flush_scheduled_work();
709}
710
711/*
712 * Ok, the machine is now initialized. None of the devices
713 * have been touched yet, but the CPU subsystem is up and
714 * running, and memory and process management works.
715 *
716 * Now we can finally start doing some real work..
717 */
718static void __init do_basic_setup(void)
719{
720 /* drivers will send hotplug events */
721 init_workqueues();
722 usermodehelper_init();
723 driver_init();
b04c3afb 724 init_irq_proc();
1da177e4
LT
725 do_initcalls();
726}
727
88d20328 728static void __init do_pre_smp_initcalls(void)
1da177e4
LT
729{
730 extern int spawn_ksoftirqd(void);
731#ifdef CONFIG_SMP
732 extern int migration_init(void);
733
734 migration_init();
735#endif
736 spawn_ksoftirqd();
8446f1d3 737 spawn_softlockup_task();
1da177e4
LT
738}
739
740static void run_init_process(char *init_filename)
741{
742 argv_init[0] = init_filename;
67608567 743 kernel_execve(init_filename, argv_init, envp_init);
1da177e4
LT
744}
745
ee5bfa64
VG
746/* This is a non __init function. Force it to be noinline otherwise gcc
747 * makes it inline to init() and it becomes part of init.text section
748 */
749static int noinline init_post(void)
750{
751 free_initmem();
752 unlock_kernel();
753 mark_rodata_ro();
754 system_state = SYSTEM_RUNNING;
755 numa_default_policy();
756
757 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
758 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
759
760 (void) sys_dup(0);
761 (void) sys_dup(0);
762
763 if (ramdisk_execute_command) {
764 run_init_process(ramdisk_execute_command);
765 printk(KERN_WARNING "Failed to execute %s\n",
766 ramdisk_execute_command);
767 }
768
769 /*
770 * We try each of these until one succeeds.
771 *
772 * The Bourne shell can be used instead of init if we are
773 * trying to recover a really broken machine.
774 */
775 if (execute_command) {
776 run_init_process(execute_command);
777 printk(KERN_WARNING "Failed to execute %s. Attempting "
778 "defaults...\n", execute_command);
779 }
780 run_init_process("/sbin/init");
781 run_init_process("/etc/init");
782 run_init_process("/bin/init");
783 run_init_process("/bin/sh");
784
785 panic("No init found. Try passing init= option to kernel.");
786}
787
aae5f662 788static int __init kernel_init(void * unused)
1da177e4
LT
789{
790 lock_kernel();
791 /*
792 * init can run on any cpu.
793 */
794 set_cpus_allowed(current, CPU_MASK_ALL);
795 /*
796 * Tell the world that we're going to be the grim
797 * reaper of innocent orphaned children.
798 *
799 * We don't want people to have to make incorrect
800 * assumptions about where in the task array this
801 * can be found.
802 */
84d73786 803 init_pid_ns.child_reaper = current;
1da177e4 804
0e29b24a 805 __set_special_pids(1, 1);
9ec52099
CLG
806 cad_pid = task_pid(current);
807
1da177e4
LT
808 smp_prepare_cpus(max_cpus);
809
810 do_pre_smp_initcalls();
811
1da177e4
LT
812 smp_init();
813 sched_init_smp();
814
815 cpuset_init_smp();
816
1da177e4
LT
817 do_basic_setup();
818
819 /*
820 * check if there is an early userspace init. If yes, let it do all
821 * the work
822 */
ffdfc409
OJ
823
824 if (!ramdisk_execute_command)
825 ramdisk_execute_command = "/init";
826
827 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
828 ramdisk_execute_command = NULL;
1da177e4 829 prepare_namespace();
ffdfc409 830 }
1da177e4
LT
831
832 /*
833 * Ok, we have completed the initial bootup, and
834 * we're essentially up and running. Get rid of the
835 * initmem segments and start the user-mode stuff..
836 */
ee5bfa64
VG
837 init_post();
838 return 0;
1da177e4 839}