blob: ee123243fb530b4d4e589f731c5bfa4652148dc8 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#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>
32#include <linux/security.h>
33#include <linux/workqueue.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/efi.h>
Shailabh Nagarc7572492006-07-14 00:24:40 -070042#include <linux/taskstats_kern.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070043#include <linux/delayacct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#include <linux/unistd.h>
45#include <linux/rmap.h>
46#include <linux/mempolicy.h>
47#include <linux/key.h>
Jan Beulich4552d5d2006-06-26 13:57:28 +020048#include <linux/unwind.h>
Adrian Bunkb6cd0b72006-06-27 02:53:54 -070049#include <linux/buffer_head.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070050#include <linux/debug_locks.h>
Ingo Molnarfbb9ce92006-07-03 00:24:50 -070051#include <linux/lockdep.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#include <asm/io.h>
54#include <asm/bugs.h>
55#include <asm/setup.h>
Andi Kleena9401992005-07-28 21:15:30 -070056#include <asm/sections.h>
Arjan van de Ven37b73c82006-01-06 00:12:01 -080057#include <asm/cacheflush.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#ifdef CONFIG_X86_LOCAL_APIC
60#include <asm/smp.h>
61#endif
62
63/*
Coywolf Qi Hunt69c99ac2006-01-14 13:21:11 -080064 * This is one of the first .c files built. Error out early if we have compiler
65 * trouble.
66 *
67 * Versions of gcc older than that listed below may actually compile and link
68 * okay, but the end product can have subtle run time bugs. To avoid associated
69 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
70 * too old from the very beginning.
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 */
Andrew Mortonfd285bb2006-01-08 01:04:07 -080072#if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -070073#error Sorry, your GCC is too old. It builds incorrect kernels.
74#endif
75
76static int init(void *);
77
78extern void init_IRQ(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079extern void fork_init(unsigned long);
80extern void mca_init(void);
81extern void sbus_init(void);
82extern void sysctl_init(void);
83extern void signals_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084extern void pidhash_init(void);
85extern void pidmap_init(void);
86extern void prio_tree_init(void);
87extern void radix_tree_init(void);
88extern void free_initmem(void);
89extern void populate_rootfs(void);
90extern void driver_init(void);
91extern void prepare_namespace(void);
92#ifdef CONFIG_ACPI
93extern void acpi_early_init(void);
94#else
95static inline void acpi_early_init(void) { }
96#endif
Arjan van de Ven37b73c82006-01-06 00:12:01 -080097#ifndef CONFIG_DEBUG_RODATA
98static inline void mark_rodata_ro(void) { }
99#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
101#ifdef CONFIG_TC
102extern void tc_init(void);
103#endif
104
105enum system_states system_state;
106EXPORT_SYMBOL(system_state);
107
108/*
109 * Boot command-line arguments
110 */
111#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
112#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
113
114extern void time_init(void);
115/* Default late time init is NULL. archs can override this later. */
116void (*late_time_init)(void);
117extern void softirq_init(void);
118
119/* Untouched command line (eg. for /proc) saved by arch-specific code. */
120char saved_command_line[COMMAND_LINE_SIZE];
121
122static char *execute_command;
Olof Johanssonffdfc402005-09-06 15:17:19 -0700123static char *ramdisk_execute_command;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
125/* Setup configured maximum number of CPUs to activate */
126static unsigned int max_cpus = NR_CPUS;
127
128/*
Vivek Goyal7e962872006-09-27 01:50:44 -0700129 * If set, this is an indication to the drivers that reset the underlying
130 * device before going ahead with the initialization otherwise driver might
131 * rely on the BIOS and skip the reset operation.
132 *
133 * This is useful if kernel is booting in an unreliable environment.
134 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
135 * skipped and devices will be in unknown state.
136 */
137unsigned int reset_devices;
138EXPORT_SYMBOL(reset_devices);
139
140/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 * Setup routine for controlling SMP activation
142 *
143 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
144 * activation entirely (the MPS table probe still happens, though).
145 *
146 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
147 * greater than 0, limits the maximum number of CPUs activated in
148 * SMP mode to <NUM>.
149 */
150static int __init nosmp(char *str)
151{
152 max_cpus = 0;
153 return 1;
154}
155
156__setup("nosmp", nosmp);
157
158static int __init maxcpus(char *str)
159{
160 get_option(&str, &max_cpus);
161 return 1;
162}
163
164__setup("maxcpus=", maxcpus);
165
Vivek Goyal7e962872006-09-27 01:50:44 -0700166static int __init set_reset_devices(char *str)
167{
168 reset_devices = 1;
169 return 1;
170}
171
172__setup("reset_devices", set_reset_devices);
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
175char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
176static const char *panic_later, *panic_param;
177
178extern struct obs_kernel_param __setup_start[], __setup_end[];
179
180static int __init obsolete_checksetup(char *line)
181{
182 struct obs_kernel_param *p;
Rusty Russell33df0d12006-09-26 10:52:32 +0200183 int had_early_param = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184
185 p = __setup_start;
186 do {
187 int n = strlen(p->str);
188 if (!strncmp(line, p->str, n)) {
189 if (p->early) {
Rusty Russell33df0d12006-09-26 10:52:32 +0200190 /* Already done in parse_early_param?
191 * (Needs exact match on param part).
192 * Keep iterating, as we can have early
193 * params and __setups of same names 8( */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 if (line[n] == '\0' || line[n] == '=')
Rusty Russell33df0d12006-09-26 10:52:32 +0200195 had_early_param = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 } else if (!p->setup_func) {
197 printk(KERN_WARNING "Parameter %s is obsolete,"
198 " ignored\n", p->str);
199 return 1;
200 } else if (p->setup_func(line + n))
201 return 1;
202 }
203 p++;
204 } while (p < __setup_end);
Rusty Russell33df0d12006-09-26 10:52:32 +0200205
206 return had_early_param;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207}
208
209/*
210 * This should be approx 2 Bo*oMips to start (note initial shift), and will
211 * still work even if initially too large, it will just take slightly longer
212 */
213unsigned long loops_per_jiffy = (1<<12);
214
215EXPORT_SYMBOL(loops_per_jiffy);
216
217static int __init debug_kernel(char *str)
218{
219 if (*str)
220 return 0;
221 console_loglevel = 10;
222 return 1;
223}
224
225static int __init quiet_kernel(char *str)
226{
227 if (*str)
228 return 0;
229 console_loglevel = 4;
230 return 1;
231}
232
233__setup("debug", debug_kernel);
234__setup("quiet", quiet_kernel);
235
236static int __init loglevel(char *str)
237{
238 get_option(&str, &console_loglevel);
239 return 1;
240}
241
242__setup("loglevel=", loglevel);
243
244/*
245 * Unknown boot options get handed to init, unless they look like
246 * failed parameters
247 */
248static int __init unknown_bootoption(char *param, char *val)
249{
250 /* Change NUL term back to "=", to make "param" the whole string. */
251 if (val) {
252 /* param=val or param="val"? */
253 if (val == param+strlen(param)+1)
254 val[-1] = '=';
255 else if (val == param+strlen(param)+2) {
256 val[-2] = '=';
257 memmove(val-1, val, strlen(val)+1);
258 val--;
259 } else
260 BUG();
261 }
262
263 /* Handle obsolete-style parameters */
264 if (obsolete_checksetup(param))
265 return 0;
266
267 /*
268 * Preemptive maintenance for "why didn't my mispelled command
269 * line work?"
270 */
271 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
272 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
273 return 0;
274 }
275
276 if (panic_later)
277 return 0;
278
279 if (val) {
280 /* Environment option */
281 unsigned int i;
282 for (i = 0; envp_init[i]; i++) {
283 if (i == MAX_INIT_ENVS) {
284 panic_later = "Too many boot env vars at `%s'";
285 panic_param = param;
286 }
287 if (!strncmp(param, envp_init[i], val - param))
288 break;
289 }
290 envp_init[i] = param;
291 } else {
292 /* Command line option */
293 unsigned int i;
294 for (i = 0; argv_init[i]; i++) {
295 if (i == MAX_INIT_ARGS) {
296 panic_later = "Too many boot init vars at `%s'";
297 panic_param = param;
298 }
299 }
300 argv_init[i] = param;
301 }
302 return 0;
303}
304
305static int __init init_setup(char *str)
306{
307 unsigned int i;
308
309 execute_command = str;
310 /*
311 * In case LILO is going to boot us with default command line,
312 * it prepends "auto" before the whole cmdline which makes
313 * the shell think it should execute a script with such name.
314 * So we ignore all arguments entered _before_ init=... [MJ]
315 */
316 for (i = 1; i < MAX_INIT_ARGS; i++)
317 argv_init[i] = NULL;
318 return 1;
319}
320__setup("init=", init_setup);
321
Olof Johanssonffdfc402005-09-06 15:17:19 -0700322static int __init rdinit_setup(char *str)
323{
324 unsigned int i;
325
326 ramdisk_execute_command = str;
327 /* See "auto" comment in init_setup */
328 for (i = 1; i < MAX_INIT_ARGS; i++)
329 argv_init[i] = NULL;
330 return 1;
331}
332__setup("rdinit=", rdinit_setup);
333
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334#ifndef CONFIG_SMP
335
336#ifdef CONFIG_X86_LOCAL_APIC
337static void __init smp_init(void)
338{
339 APIC_init_uniprocessor();
340}
341#else
342#define smp_init() do { } while (0)
343#endif
344
345static inline void setup_per_cpu_areas(void) { }
346static inline void smp_prepare_cpus(unsigned int maxcpus) { }
347
348#else
349
350#ifdef __GENERIC_PER_CPU
Eric Dumazetb73b4592006-03-23 03:01:07 -0800351unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352
353EXPORT_SYMBOL(__per_cpu_offset);
354
355static void __init setup_per_cpu_areas(void)
356{
357 unsigned long size, i;
358 char *ptr;
Eric Dumazet63872f82006-03-23 03:01:04 -0800359 unsigned long nr_possible_cpus = num_possible_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360
361 /* Copy section for each CPU (we discard the original) */
362 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
363#ifdef CONFIG_MODULES
364 if (size < PERCPU_ENOUGH_ROOM)
365 size = PERCPU_ENOUGH_ROOM;
366#endif
Eric Dumazet63872f82006-03-23 03:01:04 -0800367 ptr = alloc_bootmem(size * nr_possible_cpus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -0800369 for_each_possible_cpu(i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 __per_cpu_offset[i] = ptr - __per_cpu_start;
371 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
Eric Dumazet63872f82006-03-23 03:01:04 -0800372 ptr += size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 }
374}
375#endif /* !__GENERIC_PER_CPU */
376
377/* Called by boot processor to activate the rest. */
378static void __init smp_init(void)
379{
380 unsigned int i;
381
382 /* FIXME: This should be done in userspace --RR */
383 for_each_present_cpu(i) {
384 if (num_online_cpus() >= max_cpus)
385 break;
386 if (!cpu_online(i))
387 cpu_up(i);
388 }
389
390 /* Any cleanup work */
391 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
392 smp_cpus_done(max_cpus);
393#if 0
394 /* Get other processors into their bootup holding patterns. */
395
396 smp_commence();
397#endif
398}
399
400#endif
401
402/*
403 * We need to finalize in a non-__init function or else race conditions
404 * between the root thread and the init thread may cause start_kernel to
405 * be reaped by free_initmem before the root thread has proceeded to
406 * cpu_idle.
407 *
408 * gcc-3.4 accidentally inlines this function, so use noinline.
409 */
410
411static void noinline rest_init(void)
412 __releases(kernel_lock)
413{
414 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
415 numa_default_policy();
416 unlock_kernel();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200417
418 /*
419 * The boot idle thread must execute schedule()
420 * at least one to get things moving:
421 */
Nick Piggin5bfb5d62005-11-08 21:39:01 -0800422 preempt_enable_no_resched();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200423 schedule();
Nick Piggin5bfb5d62005-11-08 21:39:01 -0800424 preempt_disable();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200425
Nick Piggin5bfb5d62005-11-08 21:39:01 -0800426 /* Call into cpu_idle with preempt disabled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 cpu_idle();
428}
429
430/* Check for early params. */
431static int __init do_early_param(char *param, char *val)
432{
433 struct obs_kernel_param *p;
434
435 for (p = __setup_start; p < __setup_end; p++) {
436 if (p->early && strcmp(param, p->str) == 0) {
437 if (p->setup_func(val) != 0)
438 printk(KERN_WARNING
439 "Malformed early option '%s'\n", param);
440 }
441 }
442 /* We accept everything at this stage. */
443 return 0;
444}
445
446/* Arch code calls this early on, or if not, just before other parsing. */
447void __init parse_early_param(void)
448{
449 static __initdata int done = 0;
450 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
451
452 if (done)
453 return;
454
455 /* All fall through to do_early_param. */
456 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
457 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
458 done = 1;
459}
460
461/*
462 * Activate the first processor.
463 */
464
Stas Sergeev44fd2292006-03-23 02:59:44 -0800465static void __init boot_cpu_init(void)
466{
467 int cpu = smp_processor_id();
468 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
469 cpu_set(cpu, cpu_online_map);
470 cpu_set(cpu, cpu_present_map);
471 cpu_set(cpu, cpu_possible_map);
472}
473
Andrew Morton033ab7f2006-06-30 01:55:50 -0700474void __init __attribute__((weak)) smp_setup_processor_id(void)
475{
476}
477
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478asmlinkage void __init start_kernel(void)
479{
480 char * command_line;
481 extern struct kernel_param __start___param[], __stop___param[];
Andrew Morton033ab7f2006-06-30 01:55:50 -0700482
483 smp_setup_processor_id();
484
Ingo Molnarfbb9ce92006-07-03 00:24:50 -0700485 /*
486 * Need to run as early as possible, to initialize the
487 * lockdep hash:
488 */
Andi Kleenc9538ed2006-09-26 10:52:34 +0200489 unwind_init();
Ingo Molnarfbb9ce92006-07-03 00:24:50 -0700490 lockdep_init();
491
492 local_irq_disable();
493 early_boot_irqs_off();
Ingo Molnar243c7622006-07-03 00:25:06 -0700494 early_init_irq_lock_class();
Ingo Molnarfbb9ce92006-07-03 00:24:50 -0700495
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496/*
497 * Interrupts are still disabled. Do necessary setups, then
498 * enable them
499 */
500 lock_kernel();
Stas Sergeev44fd2292006-03-23 02:59:44 -0800501 boot_cpu_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 page_address_init();
503 printk(KERN_NOTICE);
504 printk(linux_banner);
505 setup_arch(&command_line);
506 setup_per_cpu_areas();
Stas Sergeev44fd2292006-03-23 02:59:44 -0800507 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
509 /*
510 * Set up the scheduler prior starting any interrupts (such as the
511 * timer interrupt). Full topology setup happens at smp_init()
512 * time - but meanwhile we still have a functioning scheduler.
513 */
514 sched_init();
515 /*
516 * Disable preemption - early bootup scheduling is extremely
517 * fragile until we cpu_idle() for the first time.
518 */
519 preempt_disable();
520 build_all_zonelists();
521 page_alloc_init();
522 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
523 parse_early_param();
524 parse_args("Booting kernel", command_line, __start___param,
525 __stop___param - __start___param,
526 &unknown_bootoption);
527 sort_main_extable();
528 trap_init();
529 rcu_init();
530 init_IRQ();
531 pidhash_init();
532 init_timers();
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800533 hrtimers_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 softirq_init();
john stultzad596172006-06-26 00:25:06 -0700535 timekeeping_init();
john stultz88fecaa2006-07-03 00:24:04 -0700536 time_init();
Heiko Carstens93e02812006-07-03 00:24:24 -0700537 profile_init();
538 if (!irqs_disabled())
539 printk("start_kernel(): bug: interrupts were enabled early\n");
Ingo Molnarfbb9ce92006-07-03 00:24:50 -0700540 early_boot_irqs_on();
Heiko Carstens93e02812006-07-03 00:24:24 -0700541 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
543 /*
544 * HACK ALERT! This is early. We're enabling the console before
545 * we've done PCI setups etc, and console_init() must be aware of
546 * this. But we do want output early, in case something goes wrong.
547 */
548 console_init();
549 if (panic_later)
550 panic(panic_later, panic_param);
Ingo Molnarfbb9ce92006-07-03 00:24:50 -0700551
552 lockdep_info();
553
Ingo Molnar9a11b49a2006-07-03 00:24:33 -0700554 /*
555 * Need to run this when irqs are enabled, because it wants
556 * to self-test [hard/soft]-irqs on/off lock inversion bugs
557 * too:
558 */
559 locking_selftest();
560
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561#ifdef CONFIG_BLK_DEV_INITRD
562 if (initrd_start && !initrd_below_start_ok &&
563 initrd_start < min_low_pfn << PAGE_SHIFT) {
564 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
565 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
566 initrd_start = 0;
567 }
568#endif
569 vfs_caches_init_early();
Paul Jacksonc417f022006-01-08 01:02:01 -0800570 cpuset_init_early();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 mem_init();
572 kmem_cache_init();
Christoph Lametere7c8d5c2005-06-21 17:14:47 -0700573 setup_per_cpu_pageset();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 numa_policy_init();
575 if (late_time_init)
576 late_time_init();
577 calibrate_delay();
578 pidmap_init();
579 pgtable_cache_init();
580 prio_tree_init();
581 anon_vma_init();
582#ifdef CONFIG_X86
583 if (efi_enabled)
584 efi_enter_virtual_mode();
585#endif
586 fork_init(num_physpages);
587 proc_caches_init();
588 buffer_init();
589 unnamed_dev_init();
590 key_init();
591 security_init();
592 vfs_caches_init(num_physpages);
593 radix_tree_init();
594 signals_init();
595 /* rootfs populating might need page-writeback */
596 page_writeback_init();
597#ifdef CONFIG_PROC_FS
598 proc_root_init();
599#endif
600 cpuset_init();
Shailabh Nagarc7572492006-07-14 00:24:40 -0700601 taskstats_init_early();
Shailabh Nagarca74e922006-07-14 00:24:36 -0700602 delayacct_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
604 check_bugs();
605
606 acpi_early_init(); /* before LAPIC and SMP init */
607
608 /* Do the rest non-__init'ed, we're now alive */
609 rest_init();
610}
611
612static int __initdata initcall_debug;
613
614static int __init initcall_debug_setup(char *str)
615{
616 initcall_debug = 1;
617 return 1;
618}
619__setup("initcall_debug", initcall_debug_setup);
620
621struct task_struct *child_reaper = &init_task;
622
623extern initcall_t __initcall_start[], __initcall_end[];
624
625static void __init do_initcalls(void)
626{
627 initcall_t *call;
628 int count = preempt_count();
629
630 for (call = __initcall_start; call < __initcall_end; call++) {
Andrew Mortonc1cda482006-03-25 03:07:15 -0800631 char *msg = NULL;
632 char msgbuf[40];
633 int result;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634
635 if (initcall_debug) {
Andrew Mortonc1cda482006-03-25 03:07:15 -0800636 printk("Calling initcall 0x%p", *call);
637 print_fn_descriptor_symbol(": %s()",
638 (unsigned long) *call);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 printk("\n");
640 }
641
Andrew Mortonc1cda482006-03-25 03:07:15 -0800642 result = (*call)();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643
Andrew Mortonf3a19cb2006-05-01 12:15:52 -0700644 if (result && result != -ENODEV && initcall_debug) {
Andrew Mortonc1cda482006-03-25 03:07:15 -0800645 sprintf(msgbuf, "error code %d", result);
646 msg = msgbuf;
647 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 if (preempt_count() != count) {
649 msg = "preemption imbalance";
650 preempt_count() = count;
651 }
652 if (irqs_disabled()) {
653 msg = "disabled interrupts";
654 local_irq_enable();
655 }
656 if (msg) {
Andrew Mortonc1cda482006-03-25 03:07:15 -0800657 printk(KERN_WARNING "initcall at 0x%p", *call);
658 print_fn_descriptor_symbol(": %s()",
659 (unsigned long) *call);
660 printk(": returned with %s\n", msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 }
662 }
663
664 /* Make sure there is no pending stuff from the initcall sequence */
665 flush_scheduled_work();
666}
667
668/*
669 * Ok, the machine is now initialized. None of the devices
670 * have been touched yet, but the CPU subsystem is up and
671 * running, and memory and process management works.
672 *
673 * Now we can finally start doing some real work..
674 */
675static void __init do_basic_setup(void)
676{
677 /* drivers will send hotplug events */
678 init_workqueues();
679 usermodehelper_init();
680 driver_init();
681
682#ifdef CONFIG_SYSCTL
683 sysctl_init();
684#endif
685
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 do_initcalls();
687}
688
689static void do_pre_smp_initcalls(void)
690{
691 extern int spawn_ksoftirqd(void);
692#ifdef CONFIG_SMP
693 extern int migration_init(void);
694
695 migration_init();
696#endif
697 spawn_ksoftirqd();
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700698 spawn_softlockup_task();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699}
700
701static void run_init_process(char *init_filename)
702{
703 argv_init[0] = init_filename;
Arnd Bergmann67608562006-10-02 02:18:26 -0700704 kernel_execve(init_filename, argv_init, envp_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705}
706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707static int init(void * unused)
708{
709 lock_kernel();
710 /*
711 * init can run on any cpu.
712 */
713 set_cpus_allowed(current, CPU_MASK_ALL);
714 /*
715 * Tell the world that we're going to be the grim
716 * reaper of innocent orphaned children.
717 *
718 * We don't want people to have to make incorrect
719 * assumptions about where in the task array this
720 * can be found.
721 */
722 child_reaper = current;
723
Cedric Le Goater9ec52092006-10-02 02:19:00 -0700724 cad_pid = task_pid(current);
725
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 smp_prepare_cpus(max_cpus);
727
728 do_pre_smp_initcalls();
729
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 smp_init();
731 sched_init_smp();
732
733 cpuset_init_smp();
734
735 /*
736 * Do this before initcalls, because some drivers want to access
737 * firmware files.
738 */
739 populate_rootfs();
740
741 do_basic_setup();
742
743 /*
744 * check if there is an early userspace init. If yes, let it do all
745 * the work
746 */
Olof Johanssonffdfc402005-09-06 15:17:19 -0700747
748 if (!ramdisk_execute_command)
749 ramdisk_execute_command = "/init";
750
751 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
752 ramdisk_execute_command = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 prepare_namespace();
Olof Johanssonffdfc402005-09-06 15:17:19 -0700754 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
756 /*
757 * Ok, we have completed the initial bootup, and
758 * we're essentially up and running. Get rid of the
759 * initmem segments and start the user-mode stuff..
760 */
761 free_initmem();
762 unlock_kernel();
Arjan van de Ven37b73c82006-01-06 00:12:01 -0800763 mark_rodata_ro();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 system_state = SYSTEM_RUNNING;
765 numa_default_policy();
766
767 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
768 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
769
770 (void) sys_dup(0);
771 (void) sys_dup(0);
Olof Johanssonffdfc402005-09-06 15:17:19 -0700772
773 if (ramdisk_execute_command) {
774 run_init_process(ramdisk_execute_command);
775 printk(KERN_WARNING "Failed to execute %s\n",
776 ramdisk_execute_command);
777 }
778
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 /*
780 * We try each of these until one succeeds.
781 *
782 * The Bourne shell can be used instead of init if we are
783 * trying to recover a really broken machine.
784 */
Avery, Brianc1d7ef72005-09-06 15:16:56 -0700785 if (execute_command) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 run_init_process(execute_command);
Avery, Brianc1d7ef72005-09-06 15:16:56 -0700787 printk(KERN_WARNING "Failed to execute %s. Attempting "
788 "defaults...\n", execute_command);
789 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 run_init_process("/sbin/init");
791 run_init_process("/etc/init");
792 run_init_process("/bin/init");
793 run_init_process("/bin/sh");
794
795 panic("No init found. Try passing init= option to kernel.");
796}