blob: b5e421e39ede7ec40d61da8345e8115a749dc0df [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>
50
51#include <asm/io.h>
52#include <asm/bugs.h>
53#include <asm/setup.h>
54
55/*
56 * This is one of the first .c files built. Error out early
57 * if we have compiler trouble..
58 */
59#if __GNUC__ == 2 && __GNUC_MINOR__ == 96
60#ifdef CONFIG_FRAME_POINTER
61#error This compiler cannot compile correctly with frame pointers enabled
62#endif
63#endif
64
65#ifdef CONFIG_X86_LOCAL_APIC
66#include <asm/smp.h>
67#endif
68
69/*
70 * Versions of gcc older than that listed below may actually compile
71 * and link okay, but the end product can have subtle run time bugs.
72 * To avoid associated bogus bug reports, we flatly refuse to compile
73 * with a gcc that is known to be too old from the very beginning.
74 */
75#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
76#error Sorry, your GCC is too old. It builds incorrect kernels.
77#endif
78
79static int init(void *);
80
81extern void init_IRQ(void);
82extern void sock_init(void);
83extern void fork_init(unsigned long);
84extern void mca_init(void);
85extern void sbus_init(void);
86extern void sysctl_init(void);
87extern void signals_init(void);
88extern void buffer_init(void);
89extern void pidhash_init(void);
90extern void pidmap_init(void);
91extern void prio_tree_init(void);
92extern void radix_tree_init(void);
93extern void free_initmem(void);
94extern void populate_rootfs(void);
95extern void driver_init(void);
96extern void prepare_namespace(void);
97#ifdef CONFIG_ACPI
98extern void acpi_early_init(void);
99#else
100static inline void acpi_early_init(void) { }
101#endif
102
103#ifdef CONFIG_TC
104extern void tc_init(void);
105#endif
106
107enum system_states system_state;
108EXPORT_SYMBOL(system_state);
109
110/*
111 * Boot command-line arguments
112 */
113#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
114#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
115
116extern void time_init(void);
117/* Default late time init is NULL. archs can override this later. */
118void (*late_time_init)(void);
119extern void softirq_init(void);
120
121/* Untouched command line (eg. for /proc) saved by arch-specific code. */
122char saved_command_line[COMMAND_LINE_SIZE];
123
124static char *execute_command;
125
126/* Setup configured maximum number of CPUs to activate */
127static unsigned int max_cpus = NR_CPUS;
128
129/*
130 * Setup routine for controlling SMP activation
131 *
132 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
133 * activation entirely (the MPS table probe still happens, though).
134 *
135 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
136 * greater than 0, limits the maximum number of CPUs activated in
137 * SMP mode to <NUM>.
138 */
139static int __init nosmp(char *str)
140{
141 max_cpus = 0;
142 return 1;
143}
144
145__setup("nosmp", nosmp);
146
147static int __init maxcpus(char *str)
148{
149 get_option(&str, &max_cpus);
150 return 1;
151}
152
153__setup("maxcpus=", maxcpus);
154
155static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
156char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
157static const char *panic_later, *panic_param;
158
159extern struct obs_kernel_param __setup_start[], __setup_end[];
160
161static int __init obsolete_checksetup(char *line)
162{
163 struct obs_kernel_param *p;
164
165 p = __setup_start;
166 do {
167 int n = strlen(p->str);
168 if (!strncmp(line, p->str, n)) {
169 if (p->early) {
170 /* Already done in parse_early_param? (Needs
171 * exact match on param part) */
172 if (line[n] == '\0' || line[n] == '=')
173 return 1;
174 } else if (!p->setup_func) {
175 printk(KERN_WARNING "Parameter %s is obsolete,"
176 " ignored\n", p->str);
177 return 1;
178 } else if (p->setup_func(line + n))
179 return 1;
180 }
181 p++;
182 } while (p < __setup_end);
183 return 0;
184}
185
186/*
187 * This should be approx 2 Bo*oMips to start (note initial shift), and will
188 * still work even if initially too large, it will just take slightly longer
189 */
190unsigned long loops_per_jiffy = (1<<12);
191
192EXPORT_SYMBOL(loops_per_jiffy);
193
194static int __init debug_kernel(char *str)
195{
196 if (*str)
197 return 0;
198 console_loglevel = 10;
199 return 1;
200}
201
202static int __init quiet_kernel(char *str)
203{
204 if (*str)
205 return 0;
206 console_loglevel = 4;
207 return 1;
208}
209
210__setup("debug", debug_kernel);
211__setup("quiet", quiet_kernel);
212
213static int __init loglevel(char *str)
214{
215 get_option(&str, &console_loglevel);
216 return 1;
217}
218
219__setup("loglevel=", loglevel);
220
221/*
222 * Unknown boot options get handed to init, unless they look like
223 * failed parameters
224 */
225static int __init unknown_bootoption(char *param, char *val)
226{
227 /* Change NUL term back to "=", to make "param" the whole string. */
228 if (val) {
229 /* param=val or param="val"? */
230 if (val == param+strlen(param)+1)
231 val[-1] = '=';
232 else if (val == param+strlen(param)+2) {
233 val[-2] = '=';
234 memmove(val-1, val, strlen(val)+1);
235 val--;
236 } else
237 BUG();
238 }
239
240 /* Handle obsolete-style parameters */
241 if (obsolete_checksetup(param))
242 return 0;
243
244 /*
245 * Preemptive maintenance for "why didn't my mispelled command
246 * line work?"
247 */
248 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
249 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
250 return 0;
251 }
252
253 if (panic_later)
254 return 0;
255
256 if (val) {
257 /* Environment option */
258 unsigned int i;
259 for (i = 0; envp_init[i]; i++) {
260 if (i == MAX_INIT_ENVS) {
261 panic_later = "Too many boot env vars at `%s'";
262 panic_param = param;
263 }
264 if (!strncmp(param, envp_init[i], val - param))
265 break;
266 }
267 envp_init[i] = param;
268 } else {
269 /* Command line option */
270 unsigned int i;
271 for (i = 0; argv_init[i]; i++) {
272 if (i == MAX_INIT_ARGS) {
273 panic_later = "Too many boot init vars at `%s'";
274 panic_param = param;
275 }
276 }
277 argv_init[i] = param;
278 }
279 return 0;
280}
281
282static int __init init_setup(char *str)
283{
284 unsigned int i;
285
286 execute_command = str;
287 /*
288 * In case LILO is going to boot us with default command line,
289 * it prepends "auto" before the whole cmdline which makes
290 * the shell think it should execute a script with such name.
291 * So we ignore all arguments entered _before_ init=... [MJ]
292 */
293 for (i = 1; i < MAX_INIT_ARGS; i++)
294 argv_init[i] = NULL;
295 return 1;
296}
297__setup("init=", init_setup);
298
299extern void setup_arch(char **);
300
301#ifndef CONFIG_SMP
302
303#ifdef CONFIG_X86_LOCAL_APIC
304static void __init smp_init(void)
305{
306 APIC_init_uniprocessor();
307}
308#else
309#define smp_init() do { } while (0)
310#endif
311
312static inline void setup_per_cpu_areas(void) { }
313static inline void smp_prepare_cpus(unsigned int maxcpus) { }
314
315#else
316
317#ifdef __GENERIC_PER_CPU
318unsigned long __per_cpu_offset[NR_CPUS];
319
320EXPORT_SYMBOL(__per_cpu_offset);
321
322static void __init setup_per_cpu_areas(void)
323{
324 unsigned long size, i;
325 char *ptr;
326 /* Created by linker magic */
327 extern char __per_cpu_start[], __per_cpu_end[];
328
329 /* Copy section for each CPU (we discard the original) */
330 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
331#ifdef CONFIG_MODULES
332 if (size < PERCPU_ENOUGH_ROOM)
333 size = PERCPU_ENOUGH_ROOM;
334#endif
335
336 ptr = alloc_bootmem(size * NR_CPUS);
337
338 for (i = 0; i < NR_CPUS; i++, ptr += size) {
339 __per_cpu_offset[i] = ptr - __per_cpu_start;
340 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
341 }
342}
343#endif /* !__GENERIC_PER_CPU */
344
345/* Called by boot processor to activate the rest. */
346static void __init smp_init(void)
347{
348 unsigned int i;
349
350 /* FIXME: This should be done in userspace --RR */
351 for_each_present_cpu(i) {
352 if (num_online_cpus() >= max_cpus)
353 break;
354 if (!cpu_online(i))
355 cpu_up(i);
356 }
357
358 /* Any cleanup work */
359 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
360 smp_cpus_done(max_cpus);
361#if 0
362 /* Get other processors into their bootup holding patterns. */
363
364 smp_commence();
365#endif
366}
367
368#endif
369
370/*
371 * We need to finalize in a non-__init function or else race conditions
372 * between the root thread and the init thread may cause start_kernel to
373 * be reaped by free_initmem before the root thread has proceeded to
374 * cpu_idle.
375 *
376 * gcc-3.4 accidentally inlines this function, so use noinline.
377 */
378
379static void noinline rest_init(void)
380 __releases(kernel_lock)
381{
382 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
383 numa_default_policy();
384 unlock_kernel();
385 preempt_enable_no_resched();
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200386
387 /*
388 * The boot idle thread must execute schedule()
389 * at least one to get things moving:
390 */
391 schedule();
392
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 cpu_idle();
394}
395
396/* Check for early params. */
397static int __init do_early_param(char *param, char *val)
398{
399 struct obs_kernel_param *p;
400
401 for (p = __setup_start; p < __setup_end; p++) {
402 if (p->early && strcmp(param, p->str) == 0) {
403 if (p->setup_func(val) != 0)
404 printk(KERN_WARNING
405 "Malformed early option '%s'\n", param);
406 }
407 }
408 /* We accept everything at this stage. */
409 return 0;
410}
411
412/* Arch code calls this early on, or if not, just before other parsing. */
413void __init parse_early_param(void)
414{
415 static __initdata int done = 0;
416 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
417
418 if (done)
419 return;
420
421 /* All fall through to do_early_param. */
422 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
423 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
424 done = 1;
425}
426
427/*
428 * Activate the first processor.
429 */
430
431asmlinkage void __init start_kernel(void)
432{
433 char * command_line;
434 extern struct kernel_param __start___param[], __stop___param[];
435/*
436 * Interrupts are still disabled. Do necessary setups, then
437 * enable them
438 */
439 lock_kernel();
440 page_address_init();
441 printk(KERN_NOTICE);
442 printk(linux_banner);
443 setup_arch(&command_line);
444 setup_per_cpu_areas();
445
446 /*
447 * Mark the boot cpu "online" so that it can call console drivers in
448 * printk() and can access its per-cpu storage.
449 */
450 smp_prepare_boot_cpu();
451
452 /*
453 * Set up the scheduler prior starting any interrupts (such as the
454 * timer interrupt). Full topology setup happens at smp_init()
455 * time - but meanwhile we still have a functioning scheduler.
456 */
457 sched_init();
458 /*
459 * Disable preemption - early bootup scheduling is extremely
460 * fragile until we cpu_idle() for the first time.
461 */
462 preempt_disable();
463 build_all_zonelists();
464 page_alloc_init();
465 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
466 parse_early_param();
467 parse_args("Booting kernel", command_line, __start___param,
468 __stop___param - __start___param,
469 &unknown_bootoption);
470 sort_main_extable();
471 trap_init();
472 rcu_init();
473 init_IRQ();
474 pidhash_init();
475 init_timers();
476 softirq_init();
477 time_init();
478
479 /*
480 * HACK ALERT! This is early. We're enabling the console before
481 * we've done PCI setups etc, and console_init() must be aware of
482 * this. But we do want output early, in case something goes wrong.
483 */
484 console_init();
485 if (panic_later)
486 panic(panic_later, panic_param);
487 profile_init();
488 local_irq_enable();
489#ifdef CONFIG_BLK_DEV_INITRD
490 if (initrd_start && !initrd_below_start_ok &&
491 initrd_start < min_low_pfn << PAGE_SHIFT) {
492 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
493 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
494 initrd_start = 0;
495 }
496#endif
497 vfs_caches_init_early();
498 mem_init();
499 kmem_cache_init();
Christoph Lametere7c8d5c2005-06-21 17:14:47 -0700500 setup_per_cpu_pageset();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 numa_policy_init();
502 if (late_time_init)
503 late_time_init();
504 calibrate_delay();
505 pidmap_init();
506 pgtable_cache_init();
507 prio_tree_init();
508 anon_vma_init();
509#ifdef CONFIG_X86
510 if (efi_enabled)
511 efi_enter_virtual_mode();
512#endif
513 fork_init(num_physpages);
514 proc_caches_init();
515 buffer_init();
516 unnamed_dev_init();
517 key_init();
518 security_init();
519 vfs_caches_init(num_physpages);
520 radix_tree_init();
521 signals_init();
522 /* rootfs populating might need page-writeback */
523 page_writeback_init();
524#ifdef CONFIG_PROC_FS
525 proc_root_init();
526#endif
527 cpuset_init();
528
529 check_bugs();
530
531 acpi_early_init(); /* before LAPIC and SMP init */
532
533 /* Do the rest non-__init'ed, we're now alive */
534 rest_init();
535}
536
537static int __initdata initcall_debug;
538
539static int __init initcall_debug_setup(char *str)
540{
541 initcall_debug = 1;
542 return 1;
543}
544__setup("initcall_debug", initcall_debug_setup);
545
546struct task_struct *child_reaper = &init_task;
547
548extern initcall_t __initcall_start[], __initcall_end[];
549
550static void __init do_initcalls(void)
551{
552 initcall_t *call;
553 int count = preempt_count();
554
555 for (call = __initcall_start; call < __initcall_end; call++) {
556 char *msg;
557
558 if (initcall_debug) {
559 printk(KERN_DEBUG "Calling initcall 0x%p", *call);
560 print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
561 printk("\n");
562 }
563
564 (*call)();
565
566 msg = NULL;
567 if (preempt_count() != count) {
568 msg = "preemption imbalance";
569 preempt_count() = count;
570 }
571 if (irqs_disabled()) {
572 msg = "disabled interrupts";
573 local_irq_enable();
574 }
575 if (msg) {
576 printk(KERN_WARNING "error in initcall at 0x%p: "
577 "returned with %s\n", *call, msg);
578 }
579 }
580
581 /* Make sure there is no pending stuff from the initcall sequence */
582 flush_scheduled_work();
583}
584
585/*
586 * Ok, the machine is now initialized. None of the devices
587 * have been touched yet, but the CPU subsystem is up and
588 * running, and memory and process management works.
589 *
590 * Now we can finally start doing some real work..
591 */
592static void __init do_basic_setup(void)
593{
594 /* drivers will send hotplug events */
595 init_workqueues();
596 usermodehelper_init();
597 driver_init();
598
599#ifdef CONFIG_SYSCTL
600 sysctl_init();
601#endif
602
603 /* Networking initialization needs a process context */
604 sock_init();
605
606 do_initcalls();
607}
608
609static void do_pre_smp_initcalls(void)
610{
611 extern int spawn_ksoftirqd(void);
612#ifdef CONFIG_SMP
613 extern int migration_init(void);
614
615 migration_init();
616#endif
617 spawn_ksoftirqd();
618}
619
620static void run_init_process(char *init_filename)
621{
622 argv_init[0] = init_filename;
623 execve(init_filename, argv_init, envp_init);
624}
625
626static inline void fixup_cpu_present_map(void)
627{
628#ifdef CONFIG_SMP
629 int i;
630
631 /*
632 * If arch is not hotplug ready and did not populate
633 * cpu_present_map, just make cpu_present_map same as cpu_possible_map
634 * for other cpu bringup code to function as normal. e.g smp_init() etc.
635 */
636 if (cpus_empty(cpu_present_map)) {
637 for_each_cpu(i) {
638 cpu_set(i, cpu_present_map);
639 }
640 }
641#endif
642}
643
644static int init(void * unused)
645{
646 lock_kernel();
647 /*
648 * init can run on any cpu.
649 */
650 set_cpus_allowed(current, CPU_MASK_ALL);
651 /*
652 * Tell the world that we're going to be the grim
653 * reaper of innocent orphaned children.
654 *
655 * We don't want people to have to make incorrect
656 * assumptions about where in the task array this
657 * can be found.
658 */
659 child_reaper = current;
660
661 /* Sets up cpus_possible() */
662 smp_prepare_cpus(max_cpus);
663
664 do_pre_smp_initcalls();
665
666 fixup_cpu_present_map();
667 smp_init();
668 sched_init_smp();
669
670 cpuset_init_smp();
671
672 /*
673 * Do this before initcalls, because some drivers want to access
674 * firmware files.
675 */
676 populate_rootfs();
677
678 do_basic_setup();
679
680 /*
681 * check if there is an early userspace init. If yes, let it do all
682 * the work
683 */
684 if (sys_access((const char __user *) "/init", 0) == 0)
685 execute_command = "/init";
686 else
687 prepare_namespace();
688
689 /*
690 * Ok, we have completed the initial bootup, and
691 * we're essentially up and running. Get rid of the
692 * initmem segments and start the user-mode stuff..
693 */
694 free_initmem();
695 unlock_kernel();
696 system_state = SYSTEM_RUNNING;
697 numa_default_policy();
698
699 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
700 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
701
702 (void) sys_dup(0);
703 (void) sys_dup(0);
704
705 /*
706 * We try each of these until one succeeds.
707 *
708 * The Bourne shell can be used instead of init if we are
709 * trying to recover a really broken machine.
710 */
711
712 if (execute_command)
713 run_init_process(execute_command);
714
715 run_init_process("/sbin/init");
716 run_init_process("/etc/init");
717 run_init_process("/bin/init");
718 run_init_process("/bin/sh");
719
720 panic("No init found. Try passing init= option to kernel.");
721}