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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 | ||
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> | |
20380731 | 50 | #include <net/sock.h> |
1da177e4 LT |
51 | |
52 | #include <asm/io.h> | |
53 | #include <asm/bugs.h> | |
54 | #include <asm/setup.h> | |
a940199f | 55 | #include <asm/sections.h> |
1da177e4 LT |
56 | |
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 | ||
81 | static int init(void *); | |
82 | ||
83 | extern void init_IRQ(void); | |
1da177e4 LT |
84 | extern void fork_init(unsigned long); |
85 | extern void mca_init(void); | |
86 | extern void sbus_init(void); | |
87 | extern void sysctl_init(void); | |
88 | extern void signals_init(void); | |
89 | extern void buffer_init(void); | |
90 | extern void pidhash_init(void); | |
91 | extern void pidmap_init(void); | |
92 | extern void prio_tree_init(void); | |
93 | extern void radix_tree_init(void); | |
94 | extern void free_initmem(void); | |
95 | extern void populate_rootfs(void); | |
96 | extern void driver_init(void); | |
97 | extern void prepare_namespace(void); | |
98 | #ifdef CONFIG_ACPI | |
99 | extern void acpi_early_init(void); | |
100 | #else | |
101 | static inline void acpi_early_init(void) { } | |
102 | #endif | |
103 | ||
104 | #ifdef CONFIG_TC | |
105 | extern void tc_init(void); | |
106 | #endif | |
107 | ||
108 | enum system_states system_state; | |
109 | EXPORT_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 | ||
117 | extern void time_init(void); | |
118 | /* Default late time init is NULL. archs can override this later. */ | |
119 | void (*late_time_init)(void); | |
120 | extern void softirq_init(void); | |
121 | ||
122 | /* Untouched command line (eg. for /proc) saved by arch-specific code. */ | |
123 | char saved_command_line[COMMAND_LINE_SIZE]; | |
124 | ||
125 | static char *execute_command; | |
126 | ||
127 | /* Setup configured maximum number of CPUs to activate */ | |
128 | static 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 | */ | |
140 | static int __init nosmp(char *str) | |
141 | { | |
142 | max_cpus = 0; | |
143 | return 1; | |
144 | } | |
145 | ||
146 | __setup("nosmp", nosmp); | |
147 | ||
148 | static int __init maxcpus(char *str) | |
149 | { | |
150 | get_option(&str, &max_cpus); | |
151 | return 1; | |
152 | } | |
153 | ||
154 | __setup("maxcpus=", maxcpus); | |
155 | ||
156 | static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; | |
157 | char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; | |
158 | static const char *panic_later, *panic_param; | |
159 | ||
160 | extern struct obs_kernel_param __setup_start[], __setup_end[]; | |
161 | ||
162 | static 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 | */ | |
191 | unsigned long loops_per_jiffy = (1<<12); | |
192 | ||
193 | EXPORT_SYMBOL(loops_per_jiffy); | |
194 | ||
195 | static int __init debug_kernel(char *str) | |
196 | { | |
197 | if (*str) | |
198 | return 0; | |
199 | console_loglevel = 10; | |
200 | return 1; | |
201 | } | |
202 | ||
203 | static 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 | ||
214 | static 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 | */ | |
226 | static 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 | ||
283 | static 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 | ||
300 | extern void setup_arch(char **); | |
301 | ||
302 | #ifndef CONFIG_SMP | |
303 | ||
304 | #ifdef CONFIG_X86_LOCAL_APIC | |
305 | static void __init smp_init(void) | |
306 | { | |
307 | APIC_init_uniprocessor(); | |
308 | } | |
309 | #else | |
310 | #define smp_init() do { } while (0) | |
311 | #endif | |
312 | ||
313 | static inline void setup_per_cpu_areas(void) { } | |
314 | static inline void smp_prepare_cpus(unsigned int maxcpus) { } | |
315 | ||
316 | #else | |
317 | ||
318 | #ifdef __GENERIC_PER_CPU | |
319 | unsigned long __per_cpu_offset[NR_CPUS]; | |
320 | ||
321 | EXPORT_SYMBOL(__per_cpu_offset); | |
322 | ||
323 | static void __init setup_per_cpu_areas(void) | |
324 | { | |
325 | unsigned long size, i; | |
326 | char *ptr; | |
1da177e4 LT |
327 | |
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. */ | |
345 | static 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 | ||
378 | static 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(); | |
f340c0d1 IM |
385 | |
386 | /* | |
387 | * The boot idle thread must execute schedule() | |
388 | * at least one to get things moving: | |
389 | */ | |
390 | schedule(); | |
391 | ||
1da177e4 LT |
392 | cpu_idle(); |
393 | } | |
394 | ||
395 | /* Check for early params. */ | |
396 | static 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. */ | |
412 | void __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 | ||
430 | asmlinkage 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(); | |
e7c8d5c9 | 499 | setup_per_cpu_pageset(); |
1da177e4 LT |
500 | 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 | ||
536 | static int __initdata initcall_debug; | |
537 | ||
538 | static int __init initcall_debug_setup(char *str) | |
539 | { | |
540 | initcall_debug = 1; | |
541 | return 1; | |
542 | } | |
543 | __setup("initcall_debug", initcall_debug_setup); | |
544 | ||
545 | struct task_struct *child_reaper = &init_task; | |
546 | ||
547 | extern initcall_t __initcall_start[], __initcall_end[]; | |
548 | ||
549 | static 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 | */ | |
591 | static 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 | ||
608 | static 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 | ||
619 | static void run_init_process(char *init_filename) | |
620 | { | |
621 | argv_init[0] = init_filename; | |
622 | execve(init_filename, argv_init, envp_init); | |
623 | } | |
624 | ||
625 | static 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 | ||
643 | static 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 | } |