blob: f142d403534190f4588b3d7eda585112077e0607 [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
12#define __KERNEL_SYSCALLS__
13
14#include <linux/config.h>
15#include <linux/types.h>
16#include <linux/module.h>
17#include <linux/proc_fs.h>
18#include <linux/devfs_fs_kernel.h>
19#include <linux/kernel.h>
20#include <linux/syscalls.h>
21#include <linux/string.h>
22#include <linux/ctype.h>
23#include <linux/delay.h>
24#include <linux/utsname.h>
25#include <linux/ioport.h>
26#include <linux/init.h>
27#include <linux/smp_lock.h>
28#include <linux/initrd.h>
29#include <linux/hdreg.h>
30#include <linux/bootmem.h>
31#include <linux/tty.h>
32#include <linux/gfp.h>
33#include <linux/percpu.h>
34#include <linux/kmod.h>
35#include <linux/kernel_stat.h>
36#include <linux/security.h>
37#include <linux/workqueue.h>
38#include <linux/profile.h>
39#include <linux/rcupdate.h>
40#include <linux/moduleparam.h>
41#include <linux/kallsyms.h>
42#include <linux/writeback.h>
43#include <linux/cpu.h>
44#include <linux/cpuset.h>
45#include <linux/efi.h>
46#include <linux/unistd.h>
47#include <linux/rmap.h>
48#include <linux/mempolicy.h>
49#include <linux/key.h>
Arnaldo Carvalho de Melo20380732005-08-16 02:18:02 -030050#include <net/sock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52#include <asm/io.h>
53#include <asm/bugs.h>
54#include <asm/setup.h>
Andi Kleena9401992005-07-28 21:15:30 -070055#include <asm/sections.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/*
58 * This is one of the first .c files built. Error out early
59 * if we have compiler trouble..
60 */
61#if __GNUC__ == 2 && __GNUC_MINOR__ == 96
62#ifdef CONFIG_FRAME_POINTER
63#error This compiler cannot compile correctly with frame pointers enabled
64#endif
65#endif
66
67#ifdef CONFIG_X86_LOCAL_APIC
68#include <asm/smp.h>
69#endif
70
71/*
72 * Versions of gcc older than that listed below may actually compile
73 * and link okay, but the end product can have subtle run time bugs.
74 * To avoid associated bogus bug reports, we flatly refuse to compile
75 * with a gcc that is known to be too old from the very beginning.
76 */
77#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
78#error Sorry, your GCC is too old. It builds incorrect kernels.
79#endif
80
81static int init(void *);
82
83extern void init_IRQ(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084extern void fork_init(unsigned long);
85extern void mca_init(void);
86extern void sbus_init(void);
87extern void sysctl_init(void);
88extern void signals_init(void);
89extern void buffer_init(void);
90extern void pidhash_init(void);
91extern void pidmap_init(void);
92extern void prio_tree_init(void);
93extern void radix_tree_init(void);
94extern void free_initmem(void);
95extern void populate_rootfs(void);
96extern void driver_init(void);
97extern void prepare_namespace(void);
98#ifdef CONFIG_ACPI
99extern void acpi_early_init(void);
100#else
101static inline void acpi_early_init(void) { }
102#endif
103
104#ifdef CONFIG_TC
105extern void tc_init(void);
106#endif
107
108enum system_states system_state;
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 (*late_time_init)(void);
120extern void softirq_init(void);
121
122/* Untouched command line (eg. for /proc) saved by arch-specific code. */
123char saved_command_line[COMMAND_LINE_SIZE];
124
125static char *execute_command;
Olof Johanssonffdfc402005-09-06 15:17:19 -0700126static char *ramdisk_execute_command;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
128/* Setup configured maximum number of CPUs to activate */
129static unsigned int max_cpus = NR_CPUS;
130
131/*
132 * Setup routine for controlling SMP activation
133 *
134 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
135 * activation entirely (the MPS table probe still happens, though).
136 *
137 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
138 * greater than 0, limits the maximum number of CPUs activated in
139 * SMP mode to <NUM>.
140 */
141static int __init nosmp(char *str)
142{
143 max_cpus = 0;
144 return 1;
145}
146
147__setup("nosmp", nosmp);
148
149static int __init maxcpus(char *str)
150{
151 get_option(&str, &max_cpus);
152 return 1;
153}
154
155__setup("maxcpus=", maxcpus);
156
157static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
158char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
159static const char *panic_later, *panic_param;
160
161extern struct obs_kernel_param __setup_start[], __setup_end[];
162
163static int __init obsolete_checksetup(char *line)
164{
165 struct obs_kernel_param *p;
166
167 p = __setup_start;
168 do {
169 int n = strlen(p->str);
170 if (!strncmp(line, p->str, n)) {
171 if (p->early) {
172 /* Already done in parse_early_param? (Needs
173 * exact match on param part) */
174 if (line[n] == '\0' || line[n] == '=')
175 return 1;
176 } else if (!p->setup_func) {
177 printk(KERN_WARNING "Parameter %s is obsolete,"
178 " ignored\n", p->str);
179 return 1;
180 } else if (p->setup_func(line + n))
181 return 1;
182 }
183 p++;
184 } while (p < __setup_end);
185 return 0;
186}
187
188/*
189 * This should be approx 2 Bo*oMips to start (note initial shift), and will
190 * still work even if initially too large, it will just take slightly longer
191 */
192unsigned long loops_per_jiffy = (1<<12);
193
194EXPORT_SYMBOL(loops_per_jiffy);
195
196static int __init debug_kernel(char *str)
197{
198 if (*str)
199 return 0;
200 console_loglevel = 10;
201 return 1;
202}
203
204static int __init quiet_kernel(char *str)
205{
206 if (*str)
207 return 0;
208 console_loglevel = 4;
209 return 1;
210}
211
212__setup("debug", debug_kernel);
213__setup("quiet", quiet_kernel);
214
215static int __init loglevel(char *str)
216{
217 get_option(&str, &console_loglevel);
218 return 1;
219}
220
221__setup("loglevel=", loglevel);
222
223/*
224 * Unknown boot options get handed to init, unless they look like
225 * failed parameters
226 */
227static int __init unknown_bootoption(char *param, char *val)
228{
229 /* Change NUL term back to "=", to make "param" the whole string. */
230 if (val) {
231 /* param=val or param="val"? */
232 if (val == param+strlen(param)+1)
233 val[-1] = '=';
234 else if (val == param+strlen(param)+2) {
235 val[-2] = '=';
236 memmove(val-1, val, strlen(val)+1);
237 val--;
238 } else
239 BUG();
240 }
241
242 /* Handle obsolete-style parameters */
243 if (obsolete_checksetup(param))
244 return 0;
245
246 /*
247 * Preemptive maintenance for "why didn't my mispelled command
248 * line work?"
249 */
250 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
251 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
252 return 0;
253 }
254
255 if (panic_later)
256 return 0;
257
258 if (val) {
259 /* Environment option */
260 unsigned int i;
261 for (i = 0; envp_init[i]; i++) {
262 if (i == MAX_INIT_ENVS) {
263 panic_later = "Too many boot env vars at `%s'";
264 panic_param = param;
265 }
266 if (!strncmp(param, envp_init[i], val - param))
267 break;
268 }
269 envp_init[i] = param;
270 } else {
271 /* Command line option */
272 unsigned int i;
273 for (i = 0; argv_init[i]; i++) {
274 if (i == MAX_INIT_ARGS) {
275 panic_later = "Too many boot init vars at `%s'";
276 panic_param = param;
277 }
278 }
279 argv_init[i] = param;
280 }
281 return 0;
282}
283
284static int __init init_setup(char *str)
285{
286 unsigned int i;
287
288 execute_command = str;
289 /*
290 * In case LILO is going to boot us with default command line,
291 * it prepends "auto" before the whole cmdline which makes
292 * the shell think it should execute a script with such name.
293 * So we ignore all arguments entered _before_ init=... [MJ]
294 */
295 for (i = 1; i < MAX_INIT_ARGS; i++)
296 argv_init[i] = NULL;
297 return 1;
298}
299__setup("init=", init_setup);
300
Olof Johanssonffdfc402005-09-06 15:17:19 -0700301static int __init rdinit_setup(char *str)
302{
303 unsigned int i;
304
305 ramdisk_execute_command = str;
306 /* See "auto" comment in init_setup */
307 for (i = 1; i < MAX_INIT_ARGS; i++)
308 argv_init[i] = NULL;
309 return 1;
310}
311__setup("rdinit=", rdinit_setup);
312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313extern void setup_arch(char **);
314
315#ifndef CONFIG_SMP
316
317#ifdef CONFIG_X86_LOCAL_APIC
318static void __init smp_init(void)
319{
320 APIC_init_uniprocessor();
321}
322#else
323#define smp_init() do { } while (0)
324#endif
325
326static inline void setup_per_cpu_areas(void) { }
327static inline void smp_prepare_cpus(unsigned int maxcpus) { }
328
329#else
330
331#ifdef __GENERIC_PER_CPU
332unsigned long __per_cpu_offset[NR_CPUS];
333
334EXPORT_SYMBOL(__per_cpu_offset);
335
336static void __init setup_per_cpu_areas(void)
337{
338 unsigned long size, i;
339 char *ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341 /* Copy section for each CPU (we discard the original) */
342 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
343#ifdef CONFIG_MODULES
344 if (size < PERCPU_ENOUGH_ROOM)
345 size = PERCPU_ENOUGH_ROOM;
346#endif
347
348 ptr = alloc_bootmem(size * NR_CPUS);
349
350 for (i = 0; i < NR_CPUS; i++, ptr += size) {
351 __per_cpu_offset[i] = ptr - __per_cpu_start;
352 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
353 }
354}
355#endif /* !__GENERIC_PER_CPU */
356
357/* Called by boot processor to activate the rest. */
358static void __init smp_init(void)
359{
360 unsigned int i;
361
362 /* FIXME: This should be done in userspace --RR */
363 for_each_present_cpu(i) {
364 if (num_online_cpus() >= max_cpus)
365 break;
366 if (!cpu_online(i))
367 cpu_up(i);
368 }
369
370 /* Any cleanup work */
371 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
372 smp_cpus_done(max_cpus);
373#if 0
374 /* Get other processors into their bootup holding patterns. */
375
376 smp_commence();
377#endif
378}
379
380#endif
381
382/*
383 * We need to finalize in a non-__init function or else race conditions
384 * between the root thread and the init thread may cause start_kernel to
385 * be reaped by free_initmem before the root thread has proceeded to
386 * cpu_idle.
387 *
388 * gcc-3.4 accidentally inlines this function, so use noinline.
389 */
390
391static void noinline rest_init(void)
392 __releases(kernel_lock)
393{
394 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
395 numa_default_policy();
396 unlock_kernel();
397 preempt_enable_no_resched();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200398
399 /*
400 * The boot idle thread must execute schedule()
401 * at least one to get things moving:
402 */
403 schedule();
404
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 cpu_idle();
406}
407
408/* Check for early params. */
409static int __init do_early_param(char *param, char *val)
410{
411 struct obs_kernel_param *p;
412
413 for (p = __setup_start; p < __setup_end; p++) {
414 if (p->early && strcmp(param, p->str) == 0) {
415 if (p->setup_func(val) != 0)
416 printk(KERN_WARNING
417 "Malformed early option '%s'\n", param);
418 }
419 }
420 /* We accept everything at this stage. */
421 return 0;
422}
423
424/* Arch code calls this early on, or if not, just before other parsing. */
425void __init parse_early_param(void)
426{
427 static __initdata int done = 0;
428 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
429
430 if (done)
431 return;
432
433 /* All fall through to do_early_param. */
434 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
435 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
436 done = 1;
437}
438
439/*
440 * Activate the first processor.
441 */
442
443asmlinkage void __init start_kernel(void)
444{
445 char * command_line;
446 extern struct kernel_param __start___param[], __stop___param[];
447/*
448 * Interrupts are still disabled. Do necessary setups, then
449 * enable them
450 */
451 lock_kernel();
452 page_address_init();
453 printk(KERN_NOTICE);
454 printk(linux_banner);
455 setup_arch(&command_line);
456 setup_per_cpu_areas();
457
458 /*
459 * Mark the boot cpu "online" so that it can call console drivers in
460 * printk() and can access its per-cpu storage.
461 */
462 smp_prepare_boot_cpu();
463
464 /*
465 * Set up the scheduler prior starting any interrupts (such as the
466 * timer interrupt). Full topology setup happens at smp_init()
467 * time - but meanwhile we still have a functioning scheduler.
468 */
469 sched_init();
470 /*
471 * Disable preemption - early bootup scheduling is extremely
472 * fragile until we cpu_idle() for the first time.
473 */
474 preempt_disable();
475 build_all_zonelists();
476 page_alloc_init();
477 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
478 parse_early_param();
479 parse_args("Booting kernel", command_line, __start___param,
480 __stop___param - __start___param,
481 &unknown_bootoption);
482 sort_main_extable();
483 trap_init();
484 rcu_init();
485 init_IRQ();
486 pidhash_init();
487 init_timers();
488 softirq_init();
489 time_init();
490
491 /*
492 * HACK ALERT! This is early. We're enabling the console before
493 * we've done PCI setups etc, and console_init() must be aware of
494 * this. But we do want output early, in case something goes wrong.
495 */
496 console_init();
497 if (panic_later)
498 panic(panic_later, panic_param);
499 profile_init();
500 local_irq_enable();
501#ifdef CONFIG_BLK_DEV_INITRD
502 if (initrd_start && !initrd_below_start_ok &&
503 initrd_start < min_low_pfn << PAGE_SHIFT) {
504 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
505 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
506 initrd_start = 0;
507 }
508#endif
509 vfs_caches_init_early();
510 mem_init();
511 kmem_cache_init();
Christoph Lametere7c8d5c2005-06-21 17:14:47 -0700512 setup_per_cpu_pageset();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 numa_policy_init();
514 if (late_time_init)
515 late_time_init();
516 calibrate_delay();
517 pidmap_init();
518 pgtable_cache_init();
519 prio_tree_init();
520 anon_vma_init();
521#ifdef CONFIG_X86
522 if (efi_enabled)
523 efi_enter_virtual_mode();
524#endif
525 fork_init(num_physpages);
526 proc_caches_init();
527 buffer_init();
528 unnamed_dev_init();
529 key_init();
530 security_init();
531 vfs_caches_init(num_physpages);
532 radix_tree_init();
533 signals_init();
534 /* rootfs populating might need page-writeback */
535 page_writeback_init();
536#ifdef CONFIG_PROC_FS
537 proc_root_init();
538#endif
539 cpuset_init();
540
541 check_bugs();
542
543 acpi_early_init(); /* before LAPIC and SMP init */
544
545 /* Do the rest non-__init'ed, we're now alive */
546 rest_init();
547}
548
549static int __initdata initcall_debug;
550
551static int __init initcall_debug_setup(char *str)
552{
553 initcall_debug = 1;
554 return 1;
555}
556__setup("initcall_debug", initcall_debug_setup);
557
558struct task_struct *child_reaper = &init_task;
559
560extern initcall_t __initcall_start[], __initcall_end[];
561
562static void __init do_initcalls(void)
563{
564 initcall_t *call;
565 int count = preempt_count();
566
567 for (call = __initcall_start; call < __initcall_end; call++) {
568 char *msg;
569
570 if (initcall_debug) {
571 printk(KERN_DEBUG "Calling initcall 0x%p", *call);
572 print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
573 printk("\n");
574 }
575
576 (*call)();
577
578 msg = NULL;
579 if (preempt_count() != count) {
580 msg = "preemption imbalance";
581 preempt_count() = count;
582 }
583 if (irqs_disabled()) {
584 msg = "disabled interrupts";
585 local_irq_enable();
586 }
587 if (msg) {
588 printk(KERN_WARNING "error in initcall at 0x%p: "
589 "returned with %s\n", *call, msg);
590 }
591 }
592
593 /* Make sure there is no pending stuff from the initcall sequence */
594 flush_scheduled_work();
595}
596
597/*
598 * Ok, the machine is now initialized. None of the devices
599 * have been touched yet, but the CPU subsystem is up and
600 * running, and memory and process management works.
601 *
602 * Now we can finally start doing some real work..
603 */
604static void __init do_basic_setup(void)
605{
606 /* drivers will send hotplug events */
607 init_workqueues();
608 usermodehelper_init();
609 driver_init();
610
611#ifdef CONFIG_SYSCTL
612 sysctl_init();
613#endif
614
615 /* Networking initialization needs a process context */
616 sock_init();
617
618 do_initcalls();
619}
620
621static void do_pre_smp_initcalls(void)
622{
623 extern int spawn_ksoftirqd(void);
624#ifdef CONFIG_SMP
625 extern int migration_init(void);
626
627 migration_init();
628#endif
629 spawn_ksoftirqd();
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700630 spawn_softlockup_task();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631}
632
633static void run_init_process(char *init_filename)
634{
635 argv_init[0] = init_filename;
636 execve(init_filename, argv_init, envp_init);
637}
638
639static inline void fixup_cpu_present_map(void)
640{
641#ifdef CONFIG_SMP
642 int i;
643
644 /*
645 * If arch is not hotplug ready and did not populate
646 * cpu_present_map, just make cpu_present_map same as cpu_possible_map
647 * for other cpu bringup code to function as normal. e.g smp_init() etc.
648 */
649 if (cpus_empty(cpu_present_map)) {
650 for_each_cpu(i) {
651 cpu_set(i, cpu_present_map);
652 }
653 }
654#endif
655}
656
657static int init(void * unused)
658{
659 lock_kernel();
660 /*
661 * init can run on any cpu.
662 */
663 set_cpus_allowed(current, CPU_MASK_ALL);
664 /*
665 * Tell the world that we're going to be the grim
666 * reaper of innocent orphaned children.
667 *
668 * We don't want people to have to make incorrect
669 * assumptions about where in the task array this
670 * can be found.
671 */
672 child_reaper = current;
673
674 /* Sets up cpus_possible() */
675 smp_prepare_cpus(max_cpus);
676
677 do_pre_smp_initcalls();
678
679 fixup_cpu_present_map();
680 smp_init();
681 sched_init_smp();
682
683 cpuset_init_smp();
684
685 /*
686 * Do this before initcalls, because some drivers want to access
687 * firmware files.
688 */
689 populate_rootfs();
690
691 do_basic_setup();
692
693 /*
694 * check if there is an early userspace init. If yes, let it do all
695 * the work
696 */
Olof Johanssonffdfc402005-09-06 15:17:19 -0700697
698 if (!ramdisk_execute_command)
699 ramdisk_execute_command = "/init";
700
701 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
702 ramdisk_execute_command = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 prepare_namespace();
Olof Johanssonffdfc402005-09-06 15:17:19 -0700704 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705
706 /*
707 * Ok, we have completed the initial bootup, and
708 * we're essentially up and running. Get rid of the
709 * initmem segments and start the user-mode stuff..
710 */
711 free_initmem();
712 unlock_kernel();
713 system_state = SYSTEM_RUNNING;
714 numa_default_policy();
715
716 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
717 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
718
719 (void) sys_dup(0);
720 (void) sys_dup(0);
Olof Johanssonffdfc402005-09-06 15:17:19 -0700721
722 if (ramdisk_execute_command) {
723 run_init_process(ramdisk_execute_command);
724 printk(KERN_WARNING "Failed to execute %s\n",
725 ramdisk_execute_command);
726 }
727
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 /*
729 * We try each of these until one succeeds.
730 *
731 * The Bourne shell can be used instead of init if we are
732 * trying to recover a really broken machine.
733 */
Avery, Brianc1d7ef72005-09-06 15:16:56 -0700734 if (execute_command) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 run_init_process(execute_command);
Avery, Brianc1d7ef72005-09-06 15:16:56 -0700736 printk(KERN_WARNING "Failed to execute %s. Attempting "
737 "defaults...\n", execute_command);
738 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 run_init_process("/sbin/init");
740 run_init_process("/etc/init");
741 run_init_process("/bin/init");
742 run_init_process("/bin/sh");
743
744 panic("No init found. Try passing init= option to kernel.");
745}