Root/init/main.c

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#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/proc_fs.h>
15#include <linux/kernel.h>
16#include <linux/syscalls.h>
17#include <linux/stackprotector.h>
18#include <linux/string.h>
19#include <linux/ctype.h>
20#include <linux/delay.h>
21#include <linux/ioport.h>
22#include <linux/init.h>
23#include <linux/smp_lock.h>
24#include <linux/initrd.h>
25#include <linux/bootmem.h>
26#include <linux/acpi.h>
27#include <linux/tty.h>
28#include <linux/percpu.h>
29#include <linux/kmod.h>
30#include <linux/vmalloc.h>
31#include <linux/kernel_stat.h>
32#include <linux/start_kernel.h>
33#include <linux/security.h>
34#include <linux/smp.h>
35#include <linux/profile.h>
36#include <linux/rcupdate.h>
37#include <linux/moduleparam.h>
38#include <linux/kallsyms.h>
39#include <linux/writeback.h>
40#include <linux/cpu.h>
41#include <linux/cpuset.h>
42#include <linux/cgroup.h>
43#include <linux/efi.h>
44#include <linux/tick.h>
45#include <linux/interrupt.h>
46#include <linux/taskstats_kern.h>
47#include <linux/delayacct.h>
48#include <linux/unistd.h>
49#include <linux/rmap.h>
50#include <linux/mempolicy.h>
51#include <linux/key.h>
52#include <linux/buffer_head.h>
53#include <linux/page_cgroup.h>
54#include <linux/debug_locks.h>
55#include <linux/debugobjects.h>
56#include <linux/lockdep.h>
57#include <linux/kmemleak.h>
58#include <linux/pid_namespace.h>
59#include <linux/device.h>
60#include <linux/kthread.h>
61#include <linux/sched.h>
62#include <linux/signal.h>
63#include <linux/idr.h>
64#include <linux/kgdb.h>
65#include <linux/ftrace.h>
66#include <linux/async.h>
67#include <linux/kmemcheck.h>
68#include <linux/sfi.h>
69#include <linux/shmem_fs.h>
70#include <linux/slab.h>
71
72#include <asm/io.h>
73#include <asm/bugs.h>
74#include <asm/setup.h>
75#include <asm/sections.h>
76#include <asm/cacheflush.h>
77
78#ifdef CONFIG_X86_LOCAL_APIC
79#include <asm/smp.h>
80#endif
81
82static int kernel_init(void *);
83
84extern void init_IRQ(void);
85extern void fork_init(unsigned long);
86extern void mca_init(void);
87extern void sbus_init(void);
88extern void prio_tree_init(void);
89extern void radix_tree_init(void);
90extern void free_initmem(void);
91#ifndef CONFIG_DEBUG_RODATA
92static inline void mark_rodata_ro(void) { }
93#endif
94
95#ifdef CONFIG_TC
96extern void tc_init(void);
97#endif
98
99enum system_states system_state __read_mostly;
100EXPORT_SYMBOL(system_state);
101
102/*
103 * Boot command-line arguments
104 */
105#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
106#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
107
108extern void time_init(void);
109/* Default late time init is NULL. archs can override this later. */
110void (*__initdata late_time_init)(void);
111extern void softirq_init(void);
112
113/* Untouched command line saved by arch-specific code. */
114char __initdata boot_command_line[COMMAND_LINE_SIZE];
115/* Untouched saved command line (eg. for /proc) */
116char *saved_command_line;
117/* Command line for parameter parsing */
118static char *static_command_line;
119
120static char *execute_command;
121static char *ramdisk_execute_command;
122
123#ifdef CONFIG_SMP
124/* Setup configured maximum number of CPUs to activate */
125unsigned int setup_max_cpus = NR_CPUS;
126EXPORT_SYMBOL(setup_max_cpus);
127
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 */
139
140void __weak arch_disable_smp_support(void) { }
141
142static int __init nosmp(char *str)
143{
144    setup_max_cpus = 0;
145    arch_disable_smp_support();
146
147    return 0;
148}
149
150early_param("nosmp", nosmp);
151
152/* this is hard limit */
153static int __init nrcpus(char *str)
154{
155    int nr_cpus;
156
157    get_option(&str, &nr_cpus);
158    if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
159        nr_cpu_ids = nr_cpus;
160
161    return 0;
162}
163
164early_param("nr_cpus", nrcpus);
165
166static int __init maxcpus(char *str)
167{
168    get_option(&str, &setup_max_cpus);
169    if (setup_max_cpus == 0)
170        arch_disable_smp_support();
171
172    return 0;
173}
174
175early_param("maxcpus", maxcpus);
176#else
177static const unsigned int setup_max_cpus = NR_CPUS;
178#endif
179
180/*
181 * If set, this is an indication to the drivers that reset the underlying
182 * device before going ahead with the initialization otherwise driver might
183 * rely on the BIOS and skip the reset operation.
184 *
185 * This is useful if kernel is booting in an unreliable environment.
186 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
187 * skipped and devices will be in unknown state.
188 */
189unsigned int reset_devices;
190EXPORT_SYMBOL(reset_devices);
191
192static int __init set_reset_devices(char *str)
193{
194    reset_devices = 1;
195    return 1;
196}
197
198__setup("reset_devices", set_reset_devices);
199
200static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
201const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
202static const char *panic_later, *panic_param;
203
204extern const struct obs_kernel_param __setup_start[], __setup_end[];
205
206static int __init obsolete_checksetup(char *line)
207{
208    const struct obs_kernel_param *p;
209    int had_early_param = 0;
210
211    p = __setup_start;
212    do {
213        int n = strlen(p->str);
214        if (!strncmp(line, p->str, n)) {
215            if (p->early) {
216                /* Already done in parse_early_param?
217                 * (Needs exact match on param part).
218                 * Keep iterating, as we can have early
219                 * params and __setups of same names 8( */
220                if (line[n] == '\0' || line[n] == '=')
221                    had_early_param = 1;
222            } else if (!p->setup_func) {
223                printk(KERN_WARNING "Parameter %s is obsolete,"
224                       " ignored\n", p->str);
225                return 1;
226            } else if (p->setup_func(line + n))
227                return 1;
228        }
229        p++;
230    } while (p < __setup_end);
231
232    return had_early_param;
233}
234
235/*
236 * This should be approx 2 Bo*oMips to start (note initial shift), and will
237 * still work even if initially too large, it will just take slightly longer
238 */
239unsigned long loops_per_jiffy = (1<<12);
240
241EXPORT_SYMBOL(loops_per_jiffy);
242
243static int __init debug_kernel(char *str)
244{
245    console_loglevel = 10;
246    return 0;
247}
248
249static int __init quiet_kernel(char *str)
250{
251    console_loglevel = 4;
252    return 0;
253}
254
255early_param("debug", debug_kernel);
256early_param("quiet", quiet_kernel);
257
258static int __init loglevel(char *str)
259{
260    get_option(&str, &console_loglevel);
261    return 0;
262}
263
264early_param("loglevel", loglevel);
265
266/*
267 * Unknown boot options get handed to init, unless they look like
268 * unused parameters (modprobe will find them in /proc/cmdline).
269 */
270static int __init unknown_bootoption(char *param, char *val)
271{
272    /* Change NUL term back to "=", to make "param" the whole string. */
273    if (val) {
274        /* param=val or param="val"? */
275        if (val == param+strlen(param)+1)
276            val[-1] = '=';
277        else if (val == param+strlen(param)+2) {
278            val[-2] = '=';
279            memmove(val-1, val, strlen(val)+1);
280            val--;
281        } else
282            BUG();
283    }
284
285    /* Handle obsolete-style parameters */
286    if (obsolete_checksetup(param))
287        return 0;
288
289    /* Unused module parameter. */
290    if (strchr(param, '.') && (!val || strchr(param, '.') < val))
291        return 0;
292
293    if (panic_later)
294        return 0;
295
296    if (val) {
297        /* Environment option */
298        unsigned int i;
299        for (i = 0; envp_init[i]; i++) {
300            if (i == MAX_INIT_ENVS) {
301                panic_later = "Too many boot env vars at `%s'";
302                panic_param = param;
303            }
304            if (!strncmp(param, envp_init[i], val - param))
305                break;
306        }
307        envp_init[i] = param;
308    } else {
309        /* Command line option */
310        unsigned int i;
311        for (i = 0; argv_init[i]; i++) {
312            if (i == MAX_INIT_ARGS) {
313                panic_later = "Too many boot init vars at `%s'";
314                panic_param = param;
315            }
316        }
317        argv_init[i] = param;
318    }
319    return 0;
320}
321
322#ifdef CONFIG_DEBUG_PAGEALLOC
323int __read_mostly debug_pagealloc_enabled = 0;
324#endif
325
326static int __init init_setup(char *str)
327{
328    unsigned int i;
329
330    execute_command = str;
331    /*
332     * In case LILO is going to boot us with default command line,
333     * it prepends "auto" before the whole cmdline which makes
334     * the shell think it should execute a script with such name.
335     * So we ignore all arguments entered _before_ init=... [MJ]
336     */
337    for (i = 1; i < MAX_INIT_ARGS; i++)
338        argv_init[i] = NULL;
339    return 1;
340}
341__setup("init=", init_setup);
342
343static int __init rdinit_setup(char *str)
344{
345    unsigned int i;
346
347    ramdisk_execute_command = str;
348    /* See "auto" comment in init_setup */
349    for (i = 1; i < MAX_INIT_ARGS; i++)
350        argv_init[i] = NULL;
351    return 1;
352}
353__setup("rdinit=", rdinit_setup);
354
355#ifndef CONFIG_SMP
356
357#ifdef CONFIG_X86_LOCAL_APIC
358static void __init smp_init(void)
359{
360    APIC_init_uniprocessor();
361}
362#else
363#define smp_init() do { } while (0)
364#endif
365
366static inline void setup_nr_cpu_ids(void) { }
367static inline void smp_prepare_cpus(unsigned int maxcpus) { }
368
369#else
370
371/* Setup number of possible processor ids */
372int nr_cpu_ids __read_mostly = NR_CPUS;
373EXPORT_SYMBOL(nr_cpu_ids);
374
375/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
376static void __init setup_nr_cpu_ids(void)
377{
378    nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
379}
380
381/* Called by boot processor to activate the rest. */
382static void __init smp_init(void)
383{
384    unsigned int cpu;
385
386    /* FIXME: This should be done in userspace --RR */
387    for_each_present_cpu(cpu) {
388        if (num_online_cpus() >= setup_max_cpus)
389            break;
390        if (!cpu_online(cpu))
391            cpu_up(cpu);
392    }
393
394    /* Any cleanup work */
395    printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
396    smp_cpus_done(setup_max_cpus);
397}
398
399#endif
400
401/*
402 * We need to store the untouched command line for future reference.
403 * We also need to store the touched command line since the parameter
404 * parsing is performed in place, and we should allow a component to
405 * store reference of name/value for future reference.
406 */
407static void __init setup_command_line(char *command_line)
408{
409    saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
410    static_command_line = alloc_bootmem(strlen (command_line)+1);
411    strcpy (saved_command_line, boot_command_line);
412    strcpy (static_command_line, command_line);
413}
414
415/*
416 * We need to finalize in a non-__init function or else race conditions
417 * between the root thread and the init thread may cause start_kernel to
418 * be reaped by free_initmem before the root thread has proceeded to
419 * cpu_idle.
420 *
421 * gcc-3.4 accidentally inlines this function, so use noinline.
422 */
423
424static __initdata DECLARE_COMPLETION(kthreadd_done);
425
426static noinline void __init_refok rest_init(void)
427    __releases(kernel_lock)
428{
429    int pid;
430
431    rcu_scheduler_starting();
432    /*
433     * We need to spawn init first so that it obtains pid 1, however
434     * the init task will end up wanting to create kthreads, which, if
435     * we schedule it before we create kthreadd, will OOPS.
436     */
437    kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
438    numa_default_policy();
439    pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
440    rcu_read_lock();
441    kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
442    rcu_read_unlock();
443    complete(&kthreadd_done);
444
445    /*
446     * The boot idle thread must execute schedule()
447     * at least once to get things moving:
448     */
449    init_idle_bootup_task(current);
450    preempt_enable_no_resched();
451    schedule();
452    preempt_disable();
453
454    /* Call into cpu_idle with preempt disabled */
455    cpu_idle();
456}
457
458/* Check for early params. */
459static int __init do_early_param(char *param, char *val)
460{
461    const struct obs_kernel_param *p;
462
463    for (p = __setup_start; p < __setup_end; p++) {
464        if ((p->early && strcmp(param, p->str) == 0) ||
465            (strcmp(param, "console") == 0 &&
466             strcmp(p->str, "earlycon") == 0)
467        ) {
468            if (p->setup_func(val) != 0)
469                printk(KERN_WARNING
470                       "Malformed early option '%s'\n", param);
471        }
472    }
473    /* We accept everything at this stage. */
474    return 0;
475}
476
477void __init parse_early_options(char *cmdline)
478{
479    parse_args("early options", cmdline, NULL, 0, do_early_param);
480}
481
482/* Arch code calls this early on, or if not, just before other parsing. */
483void __init parse_early_param(void)
484{
485    static __initdata int done = 0;
486    static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
487
488    if (done)
489        return;
490
491    /* All fall through to do_early_param. */
492    strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
493    parse_early_options(tmp_cmdline);
494    done = 1;
495}
496
497/*
498 * Activate the first processor.
499 */
500
501static void __init boot_cpu_init(void)
502{
503    int cpu = smp_processor_id();
504    /* Mark the boot cpu "present", "online" etc for SMP and UP case */
505    set_cpu_online(cpu, true);
506    set_cpu_active(cpu, true);
507    set_cpu_present(cpu, true);
508    set_cpu_possible(cpu, true);
509}
510
511void __init __weak smp_setup_processor_id(void)
512{
513}
514
515void __init __weak thread_info_cache_init(void)
516{
517}
518
519/*
520 * Set up kernel memory allocators
521 */
522static void __init mm_init(void)
523{
524    /*
525     * page_cgroup requires countinous pages as memmap
526     * and it's bigger than MAX_ORDER unless SPARSEMEM.
527     */
528    page_cgroup_init_flatmem();
529    mem_init();
530    kmem_cache_init();
531    percpu_init_late();
532    pgtable_cache_init();
533    vmalloc_init();
534}
535
536asmlinkage void __init start_kernel(void)
537{
538    char * command_line;
539    extern const struct kernel_param __start___param[], __stop___param[];
540
541    smp_setup_processor_id();
542
543    /*
544     * Need to run as early as possible, to initialize the
545     * lockdep hash:
546     */
547    lockdep_init();
548    debug_objects_early_init();
549
550    /*
551     * Set up the the initial canary ASAP:
552     */
553    boot_init_stack_canary();
554
555    cgroup_init_early();
556
557    local_irq_disable();
558    early_boot_irqs_off();
559    early_init_irq_lock_class();
560
561/*
562 * Interrupts are still disabled. Do necessary setups, then
563 * enable them
564 */
565    tick_init();
566    boot_cpu_init();
567    page_address_init();
568    printk(KERN_NOTICE "%s", linux_banner);
569    setup_arch(&command_line);
570    mm_init_owner(&init_mm, &init_task);
571    setup_command_line(command_line);
572    setup_nr_cpu_ids();
573    setup_per_cpu_areas();
574    smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
575
576    build_all_zonelists(NULL);
577    page_alloc_init();
578
579    printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
580    parse_early_param();
581    parse_args("Booting kernel", static_command_line, __start___param,
582           __stop___param - __start___param,
583           &unknown_bootoption);
584    /*
585     * These use large bootmem allocations and must precede
586     * kmem_cache_init()
587     */
588    pidhash_init();
589    vfs_caches_init_early();
590    sort_main_extable();
591    trap_init();
592    mm_init();
593    /*
594     * Set up the scheduler prior starting any interrupts (such as the
595     * timer interrupt). Full topology setup happens at smp_init()
596     * time - but meanwhile we still have a functioning scheduler.
597     */
598    sched_init();
599    /*
600     * Disable preemption - early bootup scheduling is extremely
601     * fragile until we cpu_idle() for the first time.
602     */
603    preempt_disable();
604    if (!irqs_disabled()) {
605        printk(KERN_WARNING "start_kernel(): bug: interrupts were "
606                "enabled *very* early, fixing it\n");
607        local_irq_disable();
608    }
609    rcu_init();
610    radix_tree_init();
611    /* init some links before init_ISA_irqs() */
612    early_irq_init();
613    init_IRQ();
614    prio_tree_init();
615    init_timers();
616    hrtimers_init();
617    softirq_init();
618    timekeeping_init();
619    time_init();
620    profile_init();
621    if (!irqs_disabled())
622        printk(KERN_CRIT "start_kernel(): bug: interrupts were "
623                 "enabled early\n");
624    early_boot_irqs_on();
625    local_irq_enable();
626
627    /* Interrupts are enabled now so all GFP allocations are safe. */
628    gfp_allowed_mask = __GFP_BITS_MASK;
629
630    kmem_cache_init_late();
631
632    /*
633     * HACK ALERT! This is early. We're enabling the console before
634     * we've done PCI setups etc, and console_init() must be aware of
635     * this. But we do want output early, in case something goes wrong.
636     */
637    console_init();
638    if (panic_later)
639        panic(panic_later, panic_param);
640
641    lockdep_info();
642
643    /*
644     * Need to run this when irqs are enabled, because it wants
645     * to self-test [hard/soft]-irqs on/off lock inversion bugs
646     * too:
647     */
648    locking_selftest();
649
650#ifdef CONFIG_BLK_DEV_INITRD
651    if (initrd_start && !initrd_below_start_ok &&
652        page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
653        printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
654            "disabling it.\n",
655            page_to_pfn(virt_to_page((void *)initrd_start)),
656            min_low_pfn);
657        initrd_start = 0;
658    }
659#endif
660    page_cgroup_init();
661    enable_debug_pagealloc();
662    kmemleak_init();
663    debug_objects_mem_init();
664    idr_init_cache();
665    setup_per_cpu_pageset();
666    numa_policy_init();
667    if (late_time_init)
668        late_time_init();
669    sched_clock_init();
670    calibrate_delay();
671    pidmap_init();
672    anon_vma_init();
673#ifdef CONFIG_X86
674    if (efi_enabled)
675        efi_enter_virtual_mode();
676#endif
677    thread_info_cache_init();
678    cred_init();
679    fork_init(totalram_pages);
680    proc_caches_init();
681    buffer_init();
682    key_init();
683    security_init();
684    dbg_late_init();
685    vfs_caches_init(totalram_pages);
686    signals_init();
687    /* rootfs populating might need page-writeback */
688    page_writeback_init();
689#ifdef CONFIG_PROC_FS
690    proc_root_init();
691#endif
692    cgroup_init();
693    cpuset_init();
694    taskstats_init_early();
695    delayacct_init();
696
697    check_bugs();
698
699    acpi_early_init(); /* before LAPIC and SMP init */
700    sfi_init_late();
701
702    ftrace_init();
703
704    /* Do the rest non-__init'ed, we're now alive */
705    rest_init();
706}
707
708/* Call all constructor functions linked into the kernel. */
709static void __init do_ctors(void)
710{
711#ifdef CONFIG_CONSTRUCTORS
712    ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
713
714    for (; fn < (ctor_fn_t *) __ctors_end; fn++)
715        (*fn)();
716#endif
717}
718
719int initcall_debug;
720core_param(initcall_debug, initcall_debug, bool, 0644);
721
722static char msgbuf[64];
723
724static int __init_or_module do_one_initcall_debug(initcall_t fn)
725{
726    ktime_t calltime, delta, rettime;
727    unsigned long long duration;
728    int ret;
729
730    printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
731    calltime = ktime_get();
732    ret = fn();
733    rettime = ktime_get();
734    delta = ktime_sub(rettime, calltime);
735    duration = (unsigned long long) ktime_to_ns(delta) >> 10;
736    printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
737        ret, duration);
738
739    return ret;
740}
741
742int __init_or_module do_one_initcall(initcall_t fn)
743{
744    int count = preempt_count();
745    int ret;
746
747    if (initcall_debug)
748        ret = do_one_initcall_debug(fn);
749    else
750        ret = fn();
751
752    msgbuf[0] = 0;
753
754    if (ret && ret != -ENODEV && initcall_debug)
755        sprintf(msgbuf, "error code %d ", ret);
756
757    if (preempt_count() != count) {
758        strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
759        preempt_count() = count;
760    }
761    if (irqs_disabled()) {
762        strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
763        local_irq_enable();
764    }
765    if (msgbuf[0]) {
766        printk("initcall %pF returned with %s\n", fn, msgbuf);
767    }
768
769    return ret;
770}
771
772
773extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
774
775static void __init do_initcalls(void)
776{
777    initcall_t *fn;
778
779    for (fn = __early_initcall_end; fn < __initcall_end; fn++)
780        do_one_initcall(*fn);
781
782    /* Make sure there is no pending stuff from the initcall sequence */
783    flush_scheduled_work();
784}
785
786/*
787 * Ok, the machine is now initialized. None of the devices
788 * have been touched yet, but the CPU subsystem is up and
789 * running, and memory and process management works.
790 *
791 * Now we can finally start doing some real work..
792 */
793static void __init do_basic_setup(void)
794{
795    cpuset_init_smp();
796    usermodehelper_init();
797    init_tmpfs();
798    driver_init();
799    init_irq_proc();
800    do_ctors();
801    do_initcalls();
802}
803
804static void __init do_pre_smp_initcalls(void)
805{
806    initcall_t *fn;
807
808    for (fn = __initcall_start; fn < __early_initcall_end; fn++)
809        do_one_initcall(*fn);
810}
811
812static void run_init_process(const char *init_filename)
813{
814    argv_init[0] = init_filename;
815    kernel_execve(init_filename, argv_init, envp_init);
816}
817
818/* This is a non __init function. Force it to be noinline otherwise gcc
819 * makes it inline to init() and it becomes part of init.text section
820 */
821static noinline int init_post(void)
822    __releases(kernel_lock)
823{
824    /* need to finish all async __init code before freeing the memory */
825    async_synchronize_full();
826    free_initmem();
827    mark_rodata_ro();
828    system_state = SYSTEM_RUNNING;
829    numa_default_policy();
830
831
832    current->signal->flags |= SIGNAL_UNKILLABLE;
833
834    if (ramdisk_execute_command) {
835        run_init_process(ramdisk_execute_command);
836        printk(KERN_WARNING "Failed to execute %s\n",
837                ramdisk_execute_command);
838    }
839
840    /*
841     * We try each of these until one succeeds.
842     *
843     * The Bourne shell can be used instead of init if we are
844     * trying to recover a really broken machine.
845     */
846    if (execute_command) {
847        run_init_process(execute_command);
848        printk(KERN_WARNING "Failed to execute %s. Attempting "
849                    "defaults...\n", execute_command);
850    }
851    run_init_process("/sbin/init");
852    run_init_process("/etc/init");
853    run_init_process("/bin/init");
854    run_init_process("/bin/sh");
855
856    panic("No init found. Try passing init= option to kernel. "
857          "See Linux Documentation/init.txt for guidance.");
858}
859
860static int __init kernel_init(void * unused)
861{
862    /*
863     * Wait until kthreadd is all set-up.
864     */
865    wait_for_completion(&kthreadd_done);
866    /*
867     * init can allocate pages on any node
868     */
869    set_mems_allowed(node_states[N_HIGH_MEMORY]);
870    /*
871     * init can run on any cpu.
872     */
873    set_cpus_allowed_ptr(current, cpu_all_mask);
874    /*
875     * Tell the world that we're going to be the grim
876     * reaper of innocent orphaned children.
877     *
878     * We don't want people to have to make incorrect
879     * assumptions about where in the task array this
880     * can be found.
881     */
882    init_pid_ns.child_reaper = current;
883
884    cad_pid = task_pid(current);
885
886    smp_prepare_cpus(setup_max_cpus);
887
888    do_pre_smp_initcalls();
889
890    smp_init();
891    sched_init_smp();
892
893    do_basic_setup();
894
895    /* Open the /dev/console on the rootfs, this should never fail */
896    if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
897        printk(KERN_WARNING "Warning: unable to open an initial console.\n");
898
899    (void) sys_dup(0);
900    (void) sys_dup(0);
901    /*
902     * check if there is an early userspace init. If yes, let it do all
903     * the work
904     */
905
906    if (!ramdisk_execute_command)
907        ramdisk_execute_command = "/init";
908
909    if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
910        ramdisk_execute_command = NULL;
911        prepare_namespace();
912    }
913
914    /*
915     * Ok, we have completed the initial bootup, and
916     * we're essentially up and running. Get rid of the
917     * initmem segments and start the user-mode stuff..
918     */
919
920    init_post();
921    return 0;
922}
923

Archive Download this file



interactive