blob: cb54cd3dbf05a6eb5621d53d171476ef1fde6f66 [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>
Ingo Molnar9b5609f2008-02-14 09:41:09 +010017#include <linux/stackprotector.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/string.h>
19#include <linux/ctype.h>
20#include <linux/delay.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/ioport.h>
22#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/initrd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/bootmem.h>
Len Brown4a7a16d2009-06-12 20:42:08 -040025#include <linux/acpi.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/tty.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/percpu.h>
28#include <linux/kmod.h>
Nick Piggindb64fe02008-10-18 20:27:03 -070029#include <linux/vmalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/kernel_stat.h>
Rusty Russelld7cd5612006-12-07 02:14:08 +010031#include <linux/start_kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/security.h>
Jens Axboe3d442232008-06-26 11:21:34 +020033#include <linux/smp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#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>
Paul Menageddbcc7e2007-10-18 23:39:30 -070041#include <linux/cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/efi.h>
Thomas Gleixner906568c2007-02-16 01:28:01 -080043#include <linux/tick.h>
Andrew Morton6168a702007-02-17 21:22:39 -080044#include <linux/interrupt.h>
Shailabh Nagarc7572492006-07-14 00:24:40 -070045#include <linux/taskstats_kern.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070046#include <linux/delayacct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/unistd.h>
48#include <linux/rmap.h>
49#include <linux/mempolicy.h>
50#include <linux/key.h>
Adrian Bunkb6cd0b72006-06-27 02:53:54 -070051#include <linux/buffer_head.h>
KAMEZAWA Hiroyuki94b6da52008-10-22 14:15:05 -070052#include <linux/page_cgroup.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070053#include <linux/debug_locks.h>
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -070054#include <linux/debugobjects.h>
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070055#include <linux/lockdep.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010056#include <linux/kmemleak.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080057#include <linux/pid_namespace.h>
Adrian Bunk1f217822006-12-19 13:01:28 -080058#include <linux/device.h>
Eric W. Biederman73c27992007-05-09 02:34:32 -070059#include <linux/kthread.h>
Adrian Bunke6fe6642007-11-09 22:39:39 +010060#include <linux/sched.h>
Adrian Bunka1c9eea2008-02-06 01:36:44 -080061#include <linux/signal.h>
Akinobu Mita199f0ca2008-04-29 01:03:13 -070062#include <linux/idr.h>
Jason Wessel0b4b3822010-05-20 21:04:29 -050063#include <linux/kgdb.h>
Steven Rostedt68bf21a2008-08-14 15:45:08 -040064#include <linux/ftrace.h>
Arjan van de Ven22a9d642009-01-07 08:45:46 -080065#include <linux/async.h>
Vegard Nossumdfec0722008-04-04 00:51:41 +020066#include <linux/kmemcheck.h>
Feng Tang6ae69962009-08-14 15:13:46 -040067#include <linux/sfi.h>
Kay Sievers2b2af542009-04-30 15:23:42 +020068#include <linux/shmem_fs.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090069#include <linux/slab.h>
Peter Zijlstra24a24bb2010-11-17 23:17:33 +010070#include <linux/perf_event.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
72#include <asm/io.h>
73#include <asm/bugs.h>
74#include <asm/setup.h>
Andi Kleena9401992005-07-28 21:15:30 -070075#include <asm/sections.h>
Arjan van de Ven37b73c82006-01-06 00:12:01 -080076#include <asm/cacheflush.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#ifdef CONFIG_X86_LOCAL_APIC
79#include <asm/smp.h>
80#endif
81
Sam Ravnborgaae5f662007-02-26 16:45:41 +010082static int kernel_init(void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
84extern void init_IRQ(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085extern void fork_init(unsigned long);
86extern void mca_init(void);
87extern void sbus_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088extern void prio_tree_init(void);
89extern void radix_tree_init(void);
Arjan van de Ven37b73c82006-01-06 00:12:01 -080090#ifndef CONFIG_DEBUG_RODATA
91static inline void mark_rodata_ro(void) { }
92#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
94#ifdef CONFIG_TC
95extern void tc_init(void);
96#endif
97
Tejun Heo2ce802f2011-01-20 12:06:35 +010098/*
99 * Debug helper: via this flag we know that we are in 'early bootup code'
100 * where only the boot processor is running with IRQ disabled. This means
101 * two things - IRQ must not be enabled before the flag is cleared and some
102 * operations which are not allowed with IRQ disabled are allowed while the
103 * flag is set.
104 */
105bool early_boot_irqs_disabled __read_mostly;
106
Paul E. McKenneya6826042009-02-25 18:03:42 -0800107enum system_states system_state __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108EXPORT_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. */
Jan Beulichd2e31922009-01-06 14:41:10 -0800118void (*__initdata late_time_init)(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119extern void softirq_init(void);
120
Alon Bar-Lev30d7e0d2007-02-12 00:53:52 -0800121/* Untouched command line saved by arch-specific code. */
122char __initdata boot_command_line[COMMAND_LINE_SIZE];
123/* Untouched saved command line (eg. for /proc) */
124char *saved_command_line;
125/* Command line for parameter parsing */
126static char *static_command_line;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
128static char *execute_command;
Olof Johanssonffdfc402005-09-06 15:17:19 -0700129static char *ramdisk_execute_command;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Jan Beulich8b3b2952007-07-15 23:41:07 -0700131/*
132 * If set, this is an indication to the drivers that reset the underlying
133 * device before going ahead with the initialization otherwise driver might
134 * rely on the BIOS and skip the reset operation.
135 *
136 * This is useful if kernel is booting in an unreliable environment.
137 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
138 * skipped and devices will be in unknown state.
139 */
140unsigned int reset_devices;
141EXPORT_SYMBOL(reset_devices);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Vivek Goyal7e962872006-09-27 01:50:44 -0700143static int __init set_reset_devices(char *str)
144{
145 reset_devices = 1;
146 return 1;
147}
148
149__setup("reset_devices", set_reset_devices);
150
David Howellsd7627462010-08-17 23:52:56 +0100151static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
152const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153static const char *panic_later, *panic_param;
154
Rusty Russell914dcaa2010-08-11 23:04:18 -0600155extern const struct obs_kernel_param __setup_start[], __setup_end[];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
157static int __init obsolete_checksetup(char *line)
158{
Rusty Russell914dcaa2010-08-11 23:04:18 -0600159 const struct obs_kernel_param *p;
Rusty Russell33df0d12006-09-26 10:52:32 +0200160 int had_early_param = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
162 p = __setup_start;
163 do {
164 int n = strlen(p->str);
Michal Schmidtb1e4d202011-10-10 00:03:37 +0200165 if (parameqn(line, p->str, n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 if (p->early) {
Rusty Russell33df0d12006-09-26 10:52:32 +0200167 /* Already done in parse_early_param?
168 * (Needs exact match on param part).
169 * Keep iterating, as we can have early
170 * params and __setups of same names 8( */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 if (line[n] == '\0' || line[n] == '=')
Rusty Russell33df0d12006-09-26 10:52:32 +0200172 had_early_param = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 } else if (!p->setup_func) {
174 printk(KERN_WARNING "Parameter %s is obsolete,"
175 " ignored\n", p->str);
176 return 1;
177 } else if (p->setup_func(line + n))
178 return 1;
179 }
180 p++;
181 } while (p < __setup_end);
Rusty Russell33df0d12006-09-26 10:52:32 +0200182
183 return had_early_param;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184}
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{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 console_loglevel = 10;
Yinghai Luf6f21c812008-02-08 04:21:58 -0800197 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198}
199
200static int __init quiet_kernel(char *str)
201{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 console_loglevel = 4;
Yinghai Luf6f21c812008-02-08 04:21:58 -0800203 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204}
205
Yinghai Luf6f21c812008-02-08 04:21:58 -0800206early_param("debug", debug_kernel);
207early_param("quiet", quiet_kernel);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
209static int __init loglevel(char *str)
210{
Alexander Sverdlin808bf292011-09-21 09:51:40 +0200211 int newlevel;
212
213 /*
214 * Only update loglevel value when a correct setting was passed,
215 * to prevent blind crashes (when loglevel being set to 0) that
216 * are quite hard to debug
217 */
218 if (get_option(&str, &newlevel)) {
219 console_loglevel = newlevel;
220 return 0;
221 }
222
223 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224}
225
Yinghai Luf6f21c812008-02-08 04:21:58 -0800226early_param("loglevel", loglevel);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
Chris Metcalfa99cd112012-04-06 12:53:50 -0400228/* Change NUL term back to "=", to make "param" the whole string. */
229static int __init repair_env_string(char *param, char *val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 if (val) {
232 /* param=val or param="val"? */
233 if (val == param+strlen(param)+1)
234 val[-1] = '=';
235 else if (val == param+strlen(param)+2) {
236 val[-2] = '=';
237 memmove(val-1, val, strlen(val)+1);
238 val--;
239 } else
240 BUG();
241 }
Chris Metcalfa99cd112012-04-06 12:53:50 -0400242 return 0;
243}
244
245/*
246 * Unknown boot options get handed to init, unless they look like
247 * unused parameters (modprobe will find them in /proc/cmdline).
248 */
249static int __init unknown_bootoption(char *param, char *val)
250{
251 repair_env_string(param, val);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 /* Handle obsolete-style parameters */
254 if (obsolete_checksetup(param))
255 return 0;
256
Rusty Russellf066a4f2009-12-01 14:56:44 +1030257 /* Unused module parameter. */
258 if (strchr(param, '.') && (!val || strchr(param, '.') < val))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 if (panic_later)
262 return 0;
263
264 if (val) {
265 /* Environment option */
266 unsigned int i;
267 for (i = 0; envp_init[i]; i++) {
268 if (i == MAX_INIT_ENVS) {
269 panic_later = "Too many boot env vars at `%s'";
270 panic_param = param;
271 }
272 if (!strncmp(param, envp_init[i], val - param))
273 break;
274 }
275 envp_init[i] = param;
276 } else {
277 /* Command line option */
278 unsigned int i;
279 for (i = 0; argv_init[i]; i++) {
280 if (i == MAX_INIT_ARGS) {
281 panic_later = "Too many boot init vars at `%s'";
282 panic_param = param;
283 }
284 }
285 argv_init[i] = param;
286 }
287 return 0;
288}
289
290static int __init init_setup(char *str)
291{
292 unsigned int i;
293
294 execute_command = str;
295 /*
296 * In case LILO is going to boot us with default command line,
297 * it prepends "auto" before the whole cmdline which makes
298 * the shell think it should execute a script with such name.
299 * So we ignore all arguments entered _before_ init=... [MJ]
300 */
301 for (i = 1; i < MAX_INIT_ARGS; i++)
302 argv_init[i] = NULL;
303 return 1;
304}
305__setup("init=", init_setup);
306
Olof Johanssonffdfc402005-09-06 15:17:19 -0700307static int __init rdinit_setup(char *str)
308{
309 unsigned int i;
310
311 ramdisk_execute_command = str;
312 /* See "auto" comment in init_setup */
313 for (i = 1; i < MAX_INIT_ARGS; i++)
314 argv_init[i] = NULL;
315 return 1;
316}
317__setup("rdinit=", rdinit_setup);
318
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319#ifndef CONFIG_SMP
Amerigo Wang34db18a02011-03-22 16:34:06 -0700320static const unsigned int setup_max_cpus = NR_CPUS;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321#ifdef CONFIG_X86_LOCAL_APIC
322static void __init smp_init(void)
323{
324 APIC_init_uniprocessor();
325}
326#else
327#define smp_init() do { } while (0)
328#endif
329
Mike Travise0982e92008-03-26 14:23:48 -0700330static inline void setup_nr_cpu_ids(void) { }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331static inline void smp_prepare_cpus(unsigned int maxcpus) { }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332#endif
333
334/*
Alon Bar-Lev30d7e0d2007-02-12 00:53:52 -0800335 * We need to store the untouched command line for future reference.
336 * We also need to store the touched command line since the parameter
337 * parsing is performed in place, and we should allow a component to
338 * store reference of name/value for future reference.
339 */
340static void __init setup_command_line(char *command_line)
341{
342 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
343 static_command_line = alloc_bootmem(strlen (command_line)+1);
344 strcpy (saved_command_line, boot_command_line);
345 strcpy (static_command_line, command_line);
346}
347
348/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 * We need to finalize in a non-__init function or else race conditions
350 * between the root thread and the init thread may cause start_kernel to
351 * be reaped by free_initmem before the root thread has proceeded to
352 * cpu_idle.
353 *
354 * gcc-3.4 accidentally inlines this function, so use noinline.
355 */
356
Peter Zijlstrab433c3d2010-06-28 16:51:01 +0200357static __initdata DECLARE_COMPLETION(kthreadd_done);
358
Rakib Mullickf99ebf02009-01-06 14:40:38 -0800359static noinline void __init_refok rest_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360{
Eric W. Biederman73c27992007-05-09 02:34:32 -0700361 int pid;
362
Paul E. McKenney7db905e2009-09-02 14:01:24 -0700363 rcu_scheduler_starting();
Peter Zijlstrab433c3d2010-06-28 16:51:01 +0200364 /*
Peter Zijlstra97158562010-06-30 10:37:11 +0200365 * We need to spawn init first so that it obtains pid 1, however
Peter Zijlstrab433c3d2010-06-28 16:51:01 +0200366 * the init task will end up wanting to create kthreads, which, if
367 * we schedule it before we create kthreadd, will OOPS.
368 */
Sam Ravnborgaae5f662007-02-26 16:45:41 +0100369 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 numa_default_policy();
Eric W. Biederman73c27992007-05-09 02:34:32 -0700371 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800372 rcu_read_lock();
Pavel Emelyanov5cd20452008-04-30 00:54:24 -0700373 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
Paul E. McKenneyd11c5632010-02-22 17:04:50 -0800374 rcu_read_unlock();
Peter Zijlstrab433c3d2010-06-28 16:51:01 +0200375 complete(&kthreadd_done);
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200376
377 /*
378 * The boot idle thread must execute schedule()
Ingo Molnar1df21052007-07-09 18:51:58 +0200379 * at least once to get things moving:
Ingo Molnarf340c0d2005-06-28 16:40:42 +0200380 */
Ingo Molnar1df21052007-07-09 18:51:58 +0200381 init_idle_bootup_task(current);
Thomas Gleixnerbd2f5532011-03-21 12:33:18 +0100382 schedule_preempt_disabled();
Nick Piggin5bfb5d62005-11-08 21:39:01 -0800383 /* Call into cpu_idle with preempt disabled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 cpu_idle();
Ingo Molnar1df21052007-07-09 18:51:58 +0200385}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386
387/* Check for early params. */
388static int __init do_early_param(char *param, char *val)
389{
Rusty Russell914dcaa2010-08-11 23:04:18 -0600390 const struct obs_kernel_param *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391
392 for (p = __setup_start; p < __setup_end; p++) {
Michal Schmidtb1e4d202011-10-10 00:03:37 +0200393 if ((p->early && parameq(param, p->str)) ||
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700394 (strcmp(param, "console") == 0 &&
395 strcmp(p->str, "earlycon") == 0)
396 ) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 if (p->setup_func(val) != 0)
398 printk(KERN_WARNING
399 "Malformed early option '%s'\n", param);
400 }
401 }
402 /* We accept everything at this stage. */
403 return 0;
404}
405
Magnus Damm13977092009-03-30 14:37:25 -0700406void __init parse_early_options(char *cmdline)
407{
Pawel Moll026cee02012-03-26 12:50:51 +1030408 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
Magnus Damm13977092009-03-30 14:37:25 -0700409}
410
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411/* 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. */
Alon Bar-Lev30d7e0d2007-02-12 00:53:52 -0800421 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
Magnus Damm13977092009-03-30 14:37:25 -0700422 parse_early_options(tmp_cmdline);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 done = 1;
424}
425
426/*
427 * Activate the first processor.
428 */
429
Stas Sergeev44fd2292006-03-23 02:59:44 -0800430static void __init boot_cpu_init(void)
431{
432 int cpu = smp_processor_id();
433 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
Rusty Russell915441b2009-01-01 10:12:15 +1030434 set_cpu_online(cpu, true);
Peter Zijlstra933b0612009-12-16 18:04:31 +0100435 set_cpu_active(cpu, true);
Rusty Russell915441b2009-01-01 10:12:15 +1030436 set_cpu_present(cpu, true);
437 set_cpu_possible(cpu, true);
Stas Sergeev44fd2292006-03-23 02:59:44 -0800438}
439
Benjamin Herrenschmidt839ad622008-04-18 16:56:18 +1000440void __init __weak smp_setup_processor_id(void)
Andrew Morton033ab7f2006-06-30 01:55:50 -0700441{
442}
443
Benjamin Herrenschmidt8c9843e2008-04-18 16:56:15 +1000444void __init __weak thread_info_cache_init(void)
445{
446}
447
Pekka Enberg444f4782009-06-11 18:29:06 +0300448/*
449 * Set up kernel memory allocators
450 */
451static void __init mm_init(void)
452{
KAMEZAWA Hiroyukica371c02009-06-12 10:33:53 +0300453 /*
Jim Cromie7fa87ce2012-03-14 19:12:22 -0600454 * page_cgroup requires contiguous pages,
455 * bigger than MAX_ORDER unless SPARSEMEM.
KAMEZAWA Hiroyukica371c02009-06-12 10:33:53 +0300456 */
457 page_cgroup_init_flatmem();
Pekka Enberg444f4782009-06-11 18:29:06 +0300458 mem_init();
459 kmem_cache_init();
Tejun Heo099a19d2010-06-27 18:50:00 +0200460 percpu_init_late();
Benjamin Herrenschmidtc868d552009-06-17 13:48:39 +1000461 pgtable_cache_init();
Pekka Enberg444f4782009-06-11 18:29:06 +0300462 vmalloc_init();
463}
464
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465asmlinkage void __init start_kernel(void)
466{
467 char * command_line;
Rusty Russell914dcaa2010-08-11 23:04:18 -0600468 extern const struct kernel_param __start___param[], __stop___param[];
Andrew Morton033ab7f2006-06-30 01:55:50 -0700469
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700470 /*
471 * Need to run as early as possible, to initialize the
472 * lockdep hash:
473 */
474 lockdep_init();
Ming Lei73839c52011-11-17 13:34:31 +0800475 smp_setup_processor_id();
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700476 debug_objects_early_init();
Ingo Molnar42059422008-02-14 09:44:08 +0100477
478 /*
479 * Set up the the initial canary ASAP:
480 */
481 boot_init_stack_canary();
482
Paul Menageddbcc7e2007-10-18 23:39:30 -0700483 cgroup_init_early();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700484
485 local_irq_disable();
Tejun Heo2ce802f2011-01-20 12:06:35 +0100486 early_boot_irqs_disabled = true;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700487
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488/*
489 * Interrupts are still disabled. Do necessary setups, then
490 * enable them
491 */
Thomas Gleixner906568c2007-02-16 01:28:01 -0800492 tick_init();
Stas Sergeev44fd2292006-03-23 02:59:44 -0800493 boot_cpu_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 page_address_init();
Alex Riesen657cafa2009-05-24 15:30:48 +0200495 printk(KERN_NOTICE "%s", linux_banner);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 setup_arch(&command_line);
Balbir Singhcf475ad2008-04-29 01:00:16 -0700497 mm_init_owner(&init_mm, &init_task);
Linus Torvalds6345d242011-05-29 11:32:28 -0700498 mm_init_cpumask(&init_mm);
Alon Bar-Lev30d7e0d2007-02-12 00:53:52 -0800499 setup_command_line(command_line);
Mike Travise0982e92008-03-26 14:23:48 -0700500 setup_nr_cpu_ids();
Tejun Heod6647bd2009-07-21 17:11:50 +0900501 setup_per_cpu_areas();
Stas Sergeev44fd2292006-03-23 02:59:44 -0800502 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
Haicheng Li1f522502010-05-24 14:32:51 -0700504 build_all_zonelists(NULL);
Pekka Enberg83b519e2009-06-10 19:40:04 +0300505 page_alloc_init();
506
507 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
508 parse_early_param();
509 parse_args("Booting kernel", static_command_line, __start___param,
510 __stop___param - __start___param,
Pawel Moll026cee02012-03-26 12:50:51 +1030511 0, 0, &unknown_bootoption);
Jeremy Fitzhardinge97ce2c82011-10-12 16:17:54 -0700512
513 jump_label_init();
514
Pekka Enberg83b519e2009-06-10 19:40:04 +0300515 /*
516 * These use large bootmem allocations and must precede
517 * kmem_cache_init()
518 */
Mike Travis162a7e72011-05-24 17:13:20 -0700519 setup_log_buf(0);
Pekka Enberg83b519e2009-06-10 19:40:04 +0300520 pidhash_init();
Pekka Enberg83b519e2009-06-10 19:40:04 +0300521 vfs_caches_init_early();
522 sort_main_extable();
523 trap_init();
Pekka Enberg444f4782009-06-11 18:29:06 +0300524 mm_init();
KOSAKI Motohirode03c722011-05-24 17:12:15 -0700525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 /*
527 * Set up the scheduler prior starting any interrupts (such as the
528 * timer interrupt). Full topology setup happens at smp_init()
529 * time - but meanwhile we still have a functioning scheduler.
530 */
531 sched_init();
532 /*
533 * Disable preemption - early bootup scheduling is extremely
534 * fragile until we cpu_idle() for the first time.
535 */
536 preempt_disable();
Ard van Breemenc4a68302007-01-05 16:36:19 -0800537 if (!irqs_disabled()) {
538 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
539 "enabled *very* early, fixing it\n");
540 local_irq_disable();
541 }
Peter Zijlstra9f58a202010-11-17 23:17:35 +0100542 idr_init_cache();
Peter Zijlstra24a24bb2010-11-17 23:17:33 +0100543 perf_event_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 rcu_init();
Yinghai Lu773e3eb2010-02-10 01:20:33 -0800545 radix_tree_init();
Yinghai Lu0b8f1ef2008-12-05 18:58:31 -0800546 /* init some links before init_ISA_irqs() */
547 early_irq_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 init_IRQ();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100549 prio_tree_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 init_timers();
Thomas Gleixnerc0a31322006-01-09 20:52:32 -0800551 hrtimers_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 softirq_init();
john stultzad596172006-06-26 00:25:06 -0700553 timekeeping_init();
john stultz88fecaa2006-07-03 00:24:04 -0700554 time_init();
Heiko Carstens93e02812006-07-03 00:24:24 -0700555 profile_init();
Takao Indohd8ad7d12011-03-29 12:35:04 -0400556 call_function_init();
Heiko Carstens93e02812006-07-03 00:24:24 -0700557 if (!irqs_disabled())
Ron Lee24d431d2008-11-27 02:31:57 +1030558 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
559 "enabled early\n");
Tejun Heo2ce802f2011-01-20 12:06:35 +0100560 early_boot_irqs_disabled = false;
Heiko Carstens93e02812006-07-03 00:24:24 -0700561 local_irq_enable();
Benjamin Herrenschmidtdcce2842009-06-18 13:24:12 +1000562
Pekka Enberg7e85ee02009-06-12 14:03:06 +0300563 kmem_cache_init_late();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 /*
566 * HACK ALERT! This is early. We're enabling the console before
567 * we've done PCI setups etc, and console_init() must be aware of
568 * this. But we do want output early, in case something goes wrong.
569 */
570 console_init();
571 if (panic_later)
572 panic(panic_later, panic_param);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700573
574 lockdep_info();
575
Ingo Molnar9a11b49a2006-07-03 00:24:33 -0700576 /*
577 * Need to run this when irqs are enabled, because it wants
578 * to self-test [hard/soft]-irqs on/off lock inversion bugs
579 * too:
580 */
581 locking_selftest();
582
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583#ifdef CONFIG_BLK_DEV_INITRD
584 if (initrd_start && !initrd_below_start_ok &&
Geert Uytterhoevenbd673c72008-07-29 22:33:36 -0700585 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
Geert Uytterhoevenfb6624e2008-07-17 21:16:36 +0200587 "disabling it.\n",
Geert Uytterhoevenbd673c72008-07-29 22:33:36 -0700588 page_to_pfn(virt_to_page((void *)initrd_start)),
589 min_low_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 initrd_start = 0;
591 }
592#endif
KAMEZAWA Hiroyuki94b6da52008-10-22 14:15:05 -0700593 page_cgroup_init();
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700594 debug_objects_mem_init();
Catalin Marinas9b090f22011-05-19 16:25:30 +0100595 kmemleak_init();
Christoph Lametere7c8d5c2005-06-21 17:14:47 -0700596 setup_per_cpu_pageset();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 numa_policy_init();
598 if (late_time_init)
599 late_time_init();
Thomas Gleixnerfa84e9e2009-08-21 22:01:12 +0200600 sched_clock_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 calibrate_delay();
602 pidmap_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 anon_vma_init();
604#ifdef CONFIG_X86
605 if (efi_enabled)
606 efi_enter_virtual_mode();
607#endif
Benjamin Herrenschmidt8c9843e2008-04-18 16:56:15 +1000608 thread_info_cache_init();
David Howellsd84f4f92008-11-14 10:39:23 +1100609 cred_init();
Jan Beulich44813742009-09-21 17:03:05 -0700610 fork_init(totalram_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 proc_caches_init();
612 buffer_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 key_init();
614 security_init();
Jason Wessel0b4b3822010-05-20 21:04:29 -0500615 dbg_late_init();
Jan Beulich44813742009-09-21 17:03:05 -0700616 vfs_caches_init(totalram_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 signals_init();
618 /* rootfs populating might need page-writeback */
619 page_writeback_init();
620#ifdef CONFIG_PROC_FS
621 proc_root_init();
622#endif
Paul Menageddbcc7e2007-10-18 23:39:30 -0700623 cgroup_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 cpuset_init();
Shailabh Nagarc7572492006-07-14 00:24:40 -0700625 taskstats_init_early();
Shailabh Nagarca74e922006-07-14 00:24:36 -0700626 delayacct_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
628 check_bugs();
629
630 acpi_early_init(); /* before LAPIC and SMP init */
Feng Tang6ae69962009-08-14 15:13:46 -0400631 sfi_init_late();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632
Steven Rostedt68bf21a2008-08-14 15:45:08 -0400633 ftrace_init();
634
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 /* Do the rest non-__init'ed, we're now alive */
636 rest_init();
637}
638
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -0700639/* Call all constructor functions linked into the kernel. */
640static void __init do_ctors(void)
641{
642#ifdef CONFIG_CONSTRUCTORS
H Hartley Sweeten196a15b2009-12-14 18:00:18 -0800643 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -0700644
H Hartley Sweeten196a15b2009-12-14 18:00:18 -0800645 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
646 (*fn)();
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -0700647#endif
648}
649
Rusty Russell2329abf2012-01-13 09:32:18 +1030650bool initcall_debug;
Rusty Russelld0ea3d72008-10-22 10:00:23 -0500651core_param(initcall_debug, initcall_debug, bool, 0644);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652
Ingo Molnar4a683bf2009-08-21 12:53:36 +0200653static char msgbuf[64];
Ingo Molnar4a683bf2009-08-21 12:53:36 +0200654
Kevin Winchestere4461272010-08-09 17:20:32 -0700655static int __init_or_module do_one_initcall_debug(initcall_t fn)
Linus Torvaldse0df1542008-05-15 18:14:01 -0700656{
Frederic Weisbecker74239072008-11-11 23:24:42 +0100657 ktime_t calltime, delta, rettime;
Américo Wang30dbb20e2010-05-26 18:57:53 +0800658 unsigned long long duration;
659 int ret;
Linus Torvaldse0df1542008-05-15 18:14:01 -0700660
Kevin Winchester22c5c032010-08-09 17:20:32 -0700661 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
662 calltime = ktime_get();
Américo Wang30dbb20e2010-05-26 18:57:53 +0800663 ret = fn();
Kevin Winchester22c5c032010-08-09 17:20:32 -0700664 rettime = ktime_get();
665 delta = ktime_sub(rettime, calltime);
666 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
667 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
668 ret, duration);
Linus Torvaldse0df1542008-05-15 18:14:01 -0700669
Kevin Winchester22c5c032010-08-09 17:20:32 -0700670 return ret;
671}
672
Kevin Winchestere4461272010-08-09 17:20:32 -0700673int __init_or_module do_one_initcall(initcall_t fn)
Kevin Winchester22c5c032010-08-09 17:20:32 -0700674{
675 int count = preempt_count();
676 int ret;
677
678 if (initcall_debug)
679 ret = do_one_initcall_debug(fn);
680 else
681 ret = fn();
Linus Torvaldse0df1542008-05-15 18:14:01 -0700682
683 msgbuf[0] = 0;
684
Américo Wang30dbb20e2010-05-26 18:57:53 +0800685 if (ret && ret != -ENODEV && initcall_debug)
686 sprintf(msgbuf, "error code %d ", ret);
Linus Torvaldse0df1542008-05-15 18:14:01 -0700687
688 if (preempt_count() != count) {
Cyrill Gorcunova76bfd02008-05-15 13:52:41 -0700689 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
Linus Torvaldse0df1542008-05-15 18:14:01 -0700690 preempt_count() = count;
691 }
692 if (irqs_disabled()) {
Cyrill Gorcunova76bfd02008-05-15 13:52:41 -0700693 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
Linus Torvaldse0df1542008-05-15 18:14:01 -0700694 local_irq_enable();
695 }
696 if (msgbuf[0]) {
Linus Torvalds96d746c2008-10-03 13:38:07 -0700697 printk("initcall %pF returned with %s\n", fn, msgbuf);
Linus Torvaldse0df1542008-05-15 18:14:01 -0700698 }
Arjan van de Ven59f94152008-07-30 12:49:02 -0700699
Américo Wang30dbb20e2010-05-26 18:57:53 +0800700 return ret;
Linus Torvaldse0df1542008-05-15 18:14:01 -0700701}
702
703
Pawel Moll026cee02012-03-26 12:50:51 +1030704extern initcall_t __initcall_start[];
705extern initcall_t __initcall0_start[];
706extern initcall_t __initcall1_start[];
707extern initcall_t __initcall2_start[];
708extern initcall_t __initcall3_start[];
709extern initcall_t __initcall4_start[];
710extern initcall_t __initcall5_start[];
711extern initcall_t __initcall6_start[];
712extern initcall_t __initcall7_start[];
713extern initcall_t __initcall_end[];
714
715static initcall_t *initcall_levels[] __initdata = {
716 __initcall0_start,
717 __initcall1_start,
718 __initcall2_start,
719 __initcall3_start,
720 __initcall4_start,
721 __initcall5_start,
722 __initcall6_start,
723 __initcall7_start,
724 __initcall_end,
725};
726
727static char *initcall_level_names[] __initdata = {
728 "early parameters",
729 "core parameters",
730 "postcore parameters",
731 "arch parameters",
732 "subsys parameters",
733 "fs parameters",
734 "device parameters",
735 "late parameters",
736};
737
Pawel Moll026cee02012-03-26 12:50:51 +1030738static void __init do_initcall_level(int level)
739{
740 extern const struct kernel_param __start___param[], __stop___param[];
741 initcall_t *fn;
742
743 strcpy(static_command_line, saved_command_line);
744 parse_args(initcall_level_names[level],
745 static_command_line, __start___param,
746 __stop___param - __start___param,
747 level, level,
Chris Metcalfa99cd112012-04-06 12:53:50 -0400748 repair_env_string);
Pawel Moll026cee02012-03-26 12:50:51 +1030749
750 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
751 do_one_initcall(*fn);
752}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753
754static void __init do_initcalls(void)
755{
Pawel Moll026cee02012-03-26 12:50:51 +1030756 int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
Pawel Moll026cee02012-03-26 12:50:51 +1030758 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
759 do_initcall_level(level);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760}
761
762/*
763 * Ok, the machine is now initialized. None of the devices
764 * have been touched yet, but the CPU subsystem is up and
765 * running, and memory and process management works.
766 *
767 * Now we can finally start doing some real work..
768 */
769static void __init do_basic_setup(void)
770{
Lai Jiangshan759ee092009-03-25 17:06:30 +0800771 cpuset_init_smp();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 usermodehelper_init();
Hugh Dickins41ffe5d2011-08-03 16:21:21 -0700773 shmem_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 driver_init();
Eric W. Biedermanb04c3af2007-02-14 00:33:57 -0800775 init_irq_proc();
Peter Oberparleiterb99b87f2009-06-17 16:28:03 -0700776 do_ctors();
Linus Torvaldsd5767c52011-09-28 10:23:44 -0700777 usermodehelper_enable();
wangyanqingb0f84372011-09-29 15:09:40 +0800778 do_initcalls();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779}
780
Eduard - Gabriel Munteanu7babe8d2008-07-25 19:45:11 -0700781static void __init do_pre_smp_initcalls(void)
Eduard - Gabriel Munteanuc2147a52008-07-25 19:45:11 -0700782{
H Hartley Sweeten196a15b2009-12-14 18:00:18 -0800783 initcall_t *fn;
Eduard - Gabriel Munteanuc2147a52008-07-25 19:45:11 -0700784
Pawel Moll026cee02012-03-26 12:50:51 +1030785 for (fn = __initcall_start; fn < __initcall0_start; fn++)
H Hartley Sweeten196a15b2009-12-14 18:00:18 -0800786 do_one_initcall(*fn);
Eduard - Gabriel Munteanuc2147a52008-07-25 19:45:11 -0700787}
788
David Howellsd7627462010-08-17 23:52:56 +0100789static void run_init_process(const char *init_filename)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790{
791 argv_init[0] = init_filename;
Arnd Bergmann67608562006-10-02 02:18:26 -0700792 kernel_execve(init_filename, argv_init, envp_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793}
794
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100795/* This is a non __init function. Force it to be noinline otherwise gcc
796 * makes it inline to init() and it becomes part of init.text section
797 */
Rakib Mullickf99ebf02009-01-06 14:40:38 -0800798static noinline int init_post(void)
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100799{
Arjan van de Ven22a9d642009-01-07 08:45:46 -0800800 /* need to finish all async __init code before freeing the memory */
801 async_synchronize_full();
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100802 free_initmem();
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100803 mark_rodata_ro();
804 system_state = SYSTEM_RUNNING;
805 numa_default_policy();
806
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100807
Oleg Nesterovfae5fa42008-04-30 00:53:03 -0700808 current->signal->flags |= SIGNAL_UNKILLABLE;
809
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100810 if (ramdisk_execute_command) {
811 run_init_process(ramdisk_execute_command);
812 printk(KERN_WARNING "Failed to execute %s\n",
813 ramdisk_execute_command);
814 }
815
816 /*
817 * We try each of these until one succeeds.
818 *
819 * The Bourne shell can be used instead of init if we are
820 * trying to recover a really broken machine.
821 */
822 if (execute_command) {
823 run_init_process(execute_command);
824 printk(KERN_WARNING "Failed to execute %s. Attempting "
825 "defaults...\n", execute_command);
826 }
827 run_init_process("/sbin/init");
828 run_init_process("/etc/init");
829 run_init_process("/bin/init");
830 run_init_process("/bin/sh");
831
Andreas Mohr9a85b8d2010-03-05 13:42:39 -0800832 panic("No init found. Try passing init= option to kernel. "
833 "See Linux Documentation/init.txt for guidance.");
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100834}
835
Sam Ravnborgaae5f662007-02-26 16:45:41 +0100836static int __init kernel_init(void * unused)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837{
Peter Zijlstrab433c3d2010-06-28 16:51:01 +0200838 /*
839 * Wait until kthreadd is all set-up.
840 */
841 wait_for_completion(&kthreadd_done);
Linus Torvalds31a67102012-05-21 12:52:42 -0700842
843 /* Now the scheduler is fully set up and can do blocking allocations */
844 gfp_allowed_mask = __GFP_BITS_MASK;
845
Miao Xie58568d22009-06-16 15:31:49 -0700846 /*
847 * init can allocate pages on any node
848 */
Miao Xie5ab116c2010-03-23 13:35:34 -0700849 set_mems_allowed(node_states[N_HIGH_MEMORY]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 /*
851 * init can run on any cpu.
852 */
Rusty Russell1a2142a2009-03-30 22:05:10 -0600853 set_cpus_allowed_ptr(current, cpu_all_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
Cedric Le Goater9ec52092006-10-02 02:19:00 -0700855 cad_pid = task_pid(current);
856
Andi Kleenca74a6f2008-01-30 13:33:17 +0100857 smp_prepare_cpus(setup_max_cpus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858
859 do_pre_smp_initcalls();
Peter Zijlstra004417a2010-11-25 18:38:29 +0100860 lockup_detector_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 smp_init();
863 sched_init_smp();
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 do_basic_setup();
866
Eric W. Biederman2bd3a9972010-03-02 23:53:19 -0800867 /* Open the /dev/console on the rootfs, this should never fail */
868 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
869 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
870
871 (void) sys_dup(0);
872 (void) sys_dup(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 /*
874 * check if there is an early userspace init. If yes, let it do all
875 * the work
876 */
Olof Johanssonffdfc402005-09-06 15:17:19 -0700877
878 if (!ramdisk_execute_command)
879 ramdisk_execute_command = "/init";
880
881 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
882 ramdisk_execute_command = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 prepare_namespace();
Olof Johanssonffdfc402005-09-06 15:17:19 -0700884 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885
886 /*
887 * Ok, we have completed the initial bootup, and
888 * we're essentially up and running. Get rid of the
889 * initmem segments and start the user-mode stuff..
890 */
Frederic Weisbecker71566a02008-10-31 12:57:20 +0100891
Vivek Goyalee5bfa62007-02-13 13:26:22 +0100892 init_post();
893 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894}