blob: ff410063e4e13ca6a296a680a136a15297d079de [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;
126
127/* Setup configured maximum number of CPUs to activate */
128static unsigned int max_cpus = NR_CPUS;
129
130/*
131 * Setup routine for controlling SMP activation
132 *
133 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
134 * activation entirely (the MPS table probe still happens, though).
135 *
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>.
139 */
140static int __init nosmp(char *str)
141{
142 max_cpus = 0;
143 return 1;
144}
145
146__setup("nosmp", nosmp);
147
148static int __init maxcpus(char *str)
149{
150 get_option(&str, &max_cpus);
151 return 1;
152}
153
154__setup("maxcpus=", maxcpus);
155
156static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
157char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
158static const char *panic_later, *panic_param;
159
160extern struct obs_kernel_param __setup_start[], __setup_end[];
161
162static int __init obsolete_checksetup(char *line)
163{
164 struct obs_kernel_param *p;
165
166 p = __setup_start;
167 do {
168 int n = strlen(p->str);
169 if (!strncmp(line, p->str, n)) {
170 if (p->early) {
171 /* Already done in parse_early_param? (Needs
172 * exact match on param part) */
173 if (line[n] == '\0' || line[n] == '=')
174 return 1;
175 } else if (!p->setup_func) {
176 printk(KERN_WARNING "Parameter %s is obsolete,"
177 " ignored\n", p->str);
178 return 1;
179 } else if (p->setup_func(line + n))
180 return 1;
181 }
182 p++;
183 } while (p < __setup_end);
184 return 0;
185}
186
187/*
188 * This should be approx 2 Bo*oMips to start (note initial shift), and will
189 * still work even if initially too large, it will just take slightly longer
190 */
191unsigned long loops_per_jiffy = (1<<12);
192
193EXPORT_SYMBOL(loops_per_jiffy);
194
195static int __init debug_kernel(char *str)
196{
197 if (*str)
198 return 0;
199 console_loglevel = 10;
200 return 1;
201}
202
203static int __init quiet_kernel(char *str)
204{
205 if (*str)
206 return 0;
207 console_loglevel = 4;
208 return 1;
209}
210
211__setup("debug", debug_kernel);
212__setup("quiet", quiet_kernel);
213
214static int __init loglevel(char *str)
215{
216 get_option(&str, &console_loglevel);
217 return 1;
218}
219
220__setup("loglevel=", loglevel);
221
222/*
223 * Unknown boot options get handed to init, unless they look like
224 * failed parameters
225 */
226static int __init unknown_bootoption(char *param, char *val)
227{
228 /* Change NUL term back to "=", to make "param" the whole string. */
229 if (val) {
230 /* param=val or param="val"? */
231 if (val == param+strlen(param)+1)
232 val[-1] = '=';
233 else if (val == param+strlen(param)+2) {
234 val[-2] = '=';
235 memmove(val-1, val, strlen(val)+1);
236 val--;
237 } else
238 BUG();
239 }
240
241 /* Handle obsolete-style parameters */
242 if (obsolete_checksetup(param))
243 return 0;
244
245 /*
246 * Preemptive maintenance for "why didn't my mispelled command
247 * line work?"
248 */
249 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
250 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
251 return 0;
252 }
253
254 if (panic_later)
255 return 0;
256
257 if (val) {
258 /* Environment option */
259 unsigned int i;
260 for (i = 0; envp_init[i]; i++) {
261 if (i == MAX_INIT_ENVS) {
262 panic_later = "Too many boot env vars at `%s'";
263 panic_param = param;
264 }
265 if (!strncmp(param, envp_init[i], val - param))
266 break;
267 }
268 envp_init[i] = param;
269 } else {
270 /* Command line option */
271 unsigned int i;
272 for (i = 0; argv_init[i]; i++) {
273 if (i == MAX_INIT_ARGS) {
274 panic_later = "Too many boot init vars at `%s'";
275 panic_param = param;
276 }
277 }
278 argv_init[i] = param;
279 }
280 return 0;
281}
282
283static int __init init_setup(char *str)
284{
285 unsigned int i;
286
287 execute_command = str;
288 /*
289 * In case LILO is going to boot us with default command line,
290 * it prepends "auto" before the whole cmdline which makes
291 * the shell think it should execute a script with such name.
292 * So we ignore all arguments entered _before_ init=... [MJ]
293 */
294 for (i = 1; i < MAX_INIT_ARGS; i++)
295 argv_init[i] = NULL;
296 return 1;
297}
298__setup("init=", init_setup);
299
300extern void setup_arch(char **);
301
302#ifndef CONFIG_SMP
303
304#ifdef CONFIG_X86_LOCAL_APIC
305static void __init smp_init(void)
306{
307 APIC_init_uniprocessor();
308}
309#else
310#define smp_init() do { } while (0)
311#endif
312
313static inline void setup_per_cpu_areas(void) { }
314static inline void smp_prepare_cpus(unsigned int maxcpus) { }
315
316#else
317
318#ifdef __GENERIC_PER_CPU
319unsigned long __per_cpu_offset[NR_CPUS];
320
321EXPORT_SYMBOL(__per_cpu_offset);
322
323static void __init setup_per_cpu_areas(void)
324{
325 unsigned long size, i;
326 char *ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
328 /* Copy section for each CPU (we discard the original) */
329 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
330#ifdef CONFIG_MODULES
331 if (size < PERCPU_ENOUGH_ROOM)
332 size = PERCPU_ENOUGH_ROOM;
333#endif
334
335 ptr = alloc_bootmem(size * NR_CPUS);
336
337 for (i = 0; i < NR_CPUS; i++, ptr += size) {
338 __per_cpu_offset[i] = ptr - __per_cpu_start;
339 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
340 }
341}
342#endif /* !__GENERIC_PER_CPU */
343
344/* Called by boot processor to activate the rest. */
345static void __init smp_init(void)
346{
347 unsigned int i;
348
349 /* FIXME: This should be done in userspace --RR */
350 for_each_present_cpu(i) {
351 if (num_online_cpus() >= max_cpus)
352 break;
353 if (!cpu_online(i))
354 cpu_up(i);
355 }
356
357 /* Any cleanup work */
358 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
359 smp_cpus_done(max_cpus);
360#if 0
361 /* Get other processors into their bootup holding patterns. */
362
363 smp_commence();
364#endif
365}
366
367#endif
368
369/*
370 * We need to finalize in a non-__init function or else race conditions
371 * between the root thread and the init thread may cause start_kernel to
372 * be reaped by free_initmem before the root thread has proceeded to
373 * cpu_idle.
374 *
375 * gcc-3.4 accidentally inlines this function, so use noinline.
376 */
377
378static void noinline rest_init(void)
379 __releases(kernel_lock)
380{
381 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
382 numa_default_policy();
383 unlock_kernel();
384 preempt_enable_no_resched();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200385
386 /*
387 * The boot idle thread must execute schedule()
388 * at least one to get things moving:
389 */
390 schedule();
391
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 cpu_idle();
393}
394
395/* Check for early params. */
396static int __init do_early_param(char *param, char *val)
397{
398 struct obs_kernel_param *p;
399
400 for (p = __setup_start; p < __setup_end; p++) {
401 if (p->early && strcmp(param, p->str) == 0) {
402 if (p->setup_func(val) != 0)
403 printk(KERN_WARNING
404 "Malformed early option '%s'\n", param);
405 }
406 }
407 /* We accept everything at this stage. */
408 return 0;
409}
410
411/* Arch code calls this early on, or if not, just before other parsing. */
412void __init parse_early_param(void)
413{
414 static __initdata int done = 0;
415 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
416
417 if (done)
418 return;
419
420 /* All fall through to do_early_param. */
421 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
422 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
423 done = 1;
424}
425
426/*
427 * Activate the first processor.
428 */
429
430asmlinkage void __init start_kernel(void)
431{
432 char * command_line;
433 extern struct kernel_param __start___param[], __stop___param[];
434/*
435 * Interrupts are still disabled. Do necessary setups, then
436 * enable them
437 */
438 lock_kernel();
439 page_address_init();
440 printk(KERN_NOTICE);
441 printk(linux_banner);
442 setup_arch(&command_line);
443 setup_per_cpu_areas();
444
445 /*
446 * Mark the boot cpu "online" so that it can call console drivers in
447 * printk() and can access its per-cpu storage.
448 */
449 smp_prepare_boot_cpu();
450
451 /*
452 * Set up the scheduler prior starting any interrupts (such as the
453 * timer interrupt). Full topology setup happens at smp_init()
454 * time - but meanwhile we still have a functioning scheduler.
455 */
456 sched_init();
457 /*
458 * Disable preemption - early bootup scheduling is extremely
459 * fragile until we cpu_idle() for the first time.
460 */
461 preempt_disable();
462 build_all_zonelists();
463 page_alloc_init();
464 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
465 parse_early_param();
466 parse_args("Booting kernel", command_line, __start___param,
467 __stop___param - __start___param,
468 &unknown_bootoption);
469 sort_main_extable();
470 trap_init();
471 rcu_init();
472 init_IRQ();
473 pidhash_init();
474 init_timers();
475 softirq_init();
476 time_init();
477
478 /*
479 * HACK ALERT! This is early. We're enabling the console before
480 * we've done PCI setups etc, and console_init() must be aware of
481 * this. But we do want output early, in case something goes wrong.
482 */
483 console_init();
484 if (panic_later)
485 panic(panic_later, panic_param);
486 profile_init();
487 local_irq_enable();
488#ifdef CONFIG_BLK_DEV_INITRD
489 if (initrd_start && !initrd_below_start_ok &&
490 initrd_start < min_low_pfn << PAGE_SHIFT) {
491 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
492 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
493 initrd_start = 0;
494 }
495#endif
496 vfs_caches_init_early();
497 mem_init();
498 kmem_cache_init();
Christoph Lametere7c8d5c2005-06-21 17:14:47 -0700499 setup_per_cpu_pageset();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 numa_policy_init();
501 if (late_time_init)
502 late_time_init();
503 calibrate_delay();
504 pidmap_init();
505 pgtable_cache_init();
506 prio_tree_init();
507 anon_vma_init();
508#ifdef CONFIG_X86
509 if (efi_enabled)
510 efi_enter_virtual_mode();
511#endif
512 fork_init(num_physpages);
513 proc_caches_init();
514 buffer_init();
515 unnamed_dev_init();
516 key_init();
517 security_init();
518 vfs_caches_init(num_physpages);
519 radix_tree_init();
520 signals_init();
521 /* rootfs populating might need page-writeback */
522 page_writeback_init();
523#ifdef CONFIG_PROC_FS
524 proc_root_init();
525#endif
526 cpuset_init();
527
528 check_bugs();
529
530 acpi_early_init(); /* before LAPIC and SMP init */
531
532 /* Do the rest non-__init'ed, we're now alive */
533 rest_init();
534}
535
536static int __initdata initcall_debug;
537
538static int __init initcall_debug_setup(char *str)
539{
540 initcall_debug = 1;
541 return 1;
542}
543__setup("initcall_debug", initcall_debug_setup);
544
545struct task_struct *child_reaper = &init_task;
546
547extern initcall_t __initcall_start[], __initcall_end[];
548
549static void __init do_initcalls(void)
550{
551 initcall_t *call;
552 int count = preempt_count();
553
554 for (call = __initcall_start; call < __initcall_end; call++) {
555 char *msg;
556
557 if (initcall_debug) {
558 printk(KERN_DEBUG "Calling initcall 0x%p", *call);
559 print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
560 printk("\n");
561 }
562
563 (*call)();
564
565 msg = NULL;
566 if (preempt_count() != count) {
567 msg = "preemption imbalance";
568 preempt_count() = count;
569 }
570 if (irqs_disabled()) {
571 msg = "disabled interrupts";
572 local_irq_enable();
573 }
574 if (msg) {
575 printk(KERN_WARNING "error in initcall at 0x%p: "
576 "returned with %s\n", *call, msg);
577 }
578 }
579
580 /* Make sure there is no pending stuff from the initcall sequence */
581 flush_scheduled_work();
582}
583
584/*
585 * Ok, the machine is now initialized. None of the devices
586 * have been touched yet, but the CPU subsystem is up and
587 * running, and memory and process management works.
588 *
589 * Now we can finally start doing some real work..
590 */
591static void __init do_basic_setup(void)
592{
593 /* drivers will send hotplug events */
594 init_workqueues();
595 usermodehelper_init();
596 driver_init();
597
598#ifdef CONFIG_SYSCTL
599 sysctl_init();
600#endif
601
602 /* Networking initialization needs a process context */
603 sock_init();
604
605 do_initcalls();
606}
607
608static void do_pre_smp_initcalls(void)
609{
610 extern int spawn_ksoftirqd(void);
611#ifdef CONFIG_SMP
612 extern int migration_init(void);
613
614 migration_init();
615#endif
616 spawn_ksoftirqd();
617}
618
619static void run_init_process(char *init_filename)
620{
621 argv_init[0] = init_filename;
622 execve(init_filename, argv_init, envp_init);
623}
624
625static inline void fixup_cpu_present_map(void)
626{
627#ifdef CONFIG_SMP
628 int i;
629
630 /*
631 * If arch is not hotplug ready and did not populate
632 * cpu_present_map, just make cpu_present_map same as cpu_possible_map
633 * for other cpu bringup code to function as normal. e.g smp_init() etc.
634 */
635 if (cpus_empty(cpu_present_map)) {
636 for_each_cpu(i) {
637 cpu_set(i, cpu_present_map);
638 }
639 }
640#endif
641}
642
643static int init(void * unused)
644{
645 lock_kernel();
646 /*
647 * init can run on any cpu.
648 */
649 set_cpus_allowed(current, CPU_MASK_ALL);
650 /*
651 * Tell the world that we're going to be the grim
652 * reaper of innocent orphaned children.
653 *
654 * We don't want people to have to make incorrect
655 * assumptions about where in the task array this
656 * can be found.
657 */
658 child_reaper = current;
659
660 /* Sets up cpus_possible() */
661 smp_prepare_cpus(max_cpus);
662
663 do_pre_smp_initcalls();
664
665 fixup_cpu_present_map();
666 smp_init();
667 sched_init_smp();
668
669 cpuset_init_smp();
670
671 /*
672 * Do this before initcalls, because some drivers want to access
673 * firmware files.
674 */
675 populate_rootfs();
676
677 do_basic_setup();
678
679 /*
680 * check if there is an early userspace init. If yes, let it do all
681 * the work
682 */
683 if (sys_access((const char __user *) "/init", 0) == 0)
684 execute_command = "/init";
685 else
686 prepare_namespace();
687
688 /*
689 * Ok, we have completed the initial bootup, and
690 * we're essentially up and running. Get rid of the
691 * initmem segments and start the user-mode stuff..
692 */
693 free_initmem();
694 unlock_kernel();
695 system_state = SYSTEM_RUNNING;
696 numa_default_policy();
697
698 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
699 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
700
701 (void) sys_dup(0);
702 (void) sys_dup(0);
703
704 /*
705 * We try each of these until one succeeds.
706 *
707 * The Bourne shell can be used instead of init if we are
708 * trying to recover a really broken machine.
709 */
710
711 if (execute_command)
712 run_init_process(execute_command);
713
714 run_init_process("/sbin/init");
715 run_init_process("/etc/init");
716 run_init_process("/bin/init");
717 run_init_process("/bin/sh");
718
719 panic("No init found. Try passing init= option to kernel.");
720}