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/initrd.h>
24#include <linux/bootmem.h>
25#include <linux/acpi.h>
26#include <linux/tty.h>
27#include <linux/percpu.h>
28#include <linux/kmod.h>
29#include <linux/vmalloc.h>
30#include <linux/kernel_stat.h>
31#include <linux/start_kernel.h>
32#include <linux/security.h>
33#include <linux/smp.h>
34#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>
41#include <linux/cgroup.h>
42#include <linux/efi.h>
43#include <linux/tick.h>
44#include <linux/interrupt.h>
45#include <linux/taskstats_kern.h>
46#include <linux/delayacct.h>
47#include <linux/unistd.h>
48#include <linux/rmap.h>
49#include <linux/mempolicy.h>
50#include <linux/key.h>
51#include <linux/buffer_head.h>
52#include <linux/page_cgroup.h>
53#include <linux/debug_locks.h>
54#include <linux/debugobjects.h>
55#include <linux/lockdep.h>
56#include <linux/kmemleak.h>
57#include <linux/pid_namespace.h>
58#include <linux/device.h>
59#include <linux/kthread.h>
60#include <linux/sched.h>
61#include <linux/signal.h>
62#include <linux/idr.h>
63#include <linux/kgdb.h>
64#include <linux/ftrace.h>
65#include <linux/async.h>
66#include <linux/kmemcheck.h>
67#include <linux/sfi.h>
68#include <linux/shmem_fs.h>
69#include <linux/slab.h>
70#include <linux/perf_event.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
99/*
100 * Debug helper: via this flag we know that we are in 'early bootup code'
101 * where only the boot processor is running with IRQ disabled. This means
102 * two things - IRQ must not be enabled before the flag is cleared and some
103 * operations which are not allowed with IRQ disabled are allowed while the
104 * flag is set.
105 */
106bool early_boot_irqs_disabled __read_mostly;
107
108enum system_states system_state __read_mostly;
109EXPORT_SYMBOL(system_state);
110
111/*
112 * Boot command-line arguments
113 */
114#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
115#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
116
117extern void time_init(void);
118/* Default late time init is NULL. archs can override this later. */
119void (*__initdata late_time_init)(void);
120extern void softirq_init(void);
121
122/* Untouched command line saved by arch-specific code. */
123char __initdata boot_command_line[COMMAND_LINE_SIZE];
124/* Untouched saved command line (eg. for /proc) */
125char *saved_command_line;
126/* Command line for parameter parsing */
127static char *static_command_line;
128
129static char *execute_command;
130static char *ramdisk_execute_command;
131
132#ifdef CONFIG_SMP
133/* Setup configured maximum number of CPUs to activate */
134unsigned int setup_max_cpus = NR_CPUS;
135EXPORT_SYMBOL(setup_max_cpus);
136
137
138/*
139 * Setup routine for controlling SMP activation
140 *
141 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
142 * activation entirely (the MPS table probe still happens, though).
143 *
144 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
145 * greater than 0, limits the maximum number of CPUs activated in
146 * SMP mode to <NUM>.
147 */
148
149void __weak arch_disable_smp_support(void) { }
150
151static int __init nosmp(char *str)
152{
153    setup_max_cpus = 0;
154    arch_disable_smp_support();
155
156    return 0;
157}
158
159early_param("nosmp", nosmp);
160
161/* this is hard limit */
162static int __init nrcpus(char *str)
163{
164    int nr_cpus;
165
166    get_option(&str, &nr_cpus);
167    if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
168        nr_cpu_ids = nr_cpus;
169
170    return 0;
171}
172
173early_param("nr_cpus", nrcpus);
174
175static int __init maxcpus(char *str)
176{
177    get_option(&str, &setup_max_cpus);
178    if (setup_max_cpus == 0)
179        arch_disable_smp_support();
180
181    return 0;
182}
183
184early_param("maxcpus", maxcpus);
185#else
186static const unsigned int setup_max_cpus = NR_CPUS;
187#endif
188
189/*
190 * If set, this is an indication to the drivers that reset the underlying
191 * device before going ahead with the initialization otherwise driver might
192 * rely on the BIOS and skip the reset operation.
193 *
194 * This is useful if kernel is booting in an unreliable environment.
195 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
196 * skipped and devices will be in unknown state.
197 */
198unsigned int reset_devices;
199EXPORT_SYMBOL(reset_devices);
200
201static int __init set_reset_devices(char *str)
202{
203    reset_devices = 1;
204    return 1;
205}
206
207__setup("reset_devices", set_reset_devices);
208
209static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
210const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
211static const char *panic_later, *panic_param;
212
213extern const struct obs_kernel_param __setup_start[], __setup_end[];
214
215static int __init obsolete_checksetup(char *line)
216{
217    const struct obs_kernel_param *p;
218    int had_early_param = 0;
219
220    p = __setup_start;
221    do {
222        int n = strlen(p->str);
223        if (!strncmp(line, p->str, n)) {
224            if (p->early) {
225                /* Already done in parse_early_param?
226                 * (Needs exact match on param part).
227                 * Keep iterating, as we can have early
228                 * params and __setups of same names 8( */
229                if (line[n] == '\0' || line[n] == '=')
230                    had_early_param = 1;
231            } else if (!p->setup_func) {
232                printk(KERN_WARNING "Parameter %s is obsolete,"
233                       " ignored\n", p->str);
234                return 1;
235            } else if (p->setup_func(line + n))
236                return 1;
237        }
238        p++;
239    } while (p < __setup_end);
240
241    return had_early_param;
242}
243
244/*
245 * This should be approx 2 Bo*oMips to start (note initial shift), and will
246 * still work even if initially too large, it will just take slightly longer
247 */
248unsigned long loops_per_jiffy = (1<<12);
249
250EXPORT_SYMBOL(loops_per_jiffy);
251
252static int __init debug_kernel(char *str)
253{
254    console_loglevel = 10;
255    return 0;
256}
257
258static int __init quiet_kernel(char *str)
259{
260    console_loglevel = 4;
261    return 0;
262}
263
264early_param("debug", debug_kernel);
265early_param("quiet", quiet_kernel);
266
267static int __init loglevel(char *str)
268{
269    get_option(&str, &console_loglevel);
270    return 0;
271}
272
273early_param("loglevel", loglevel);
274
275/*
276 * Unknown boot options get handed to init, unless they look like
277 * unused parameters (modprobe will find them in /proc/cmdline).
278 */
279static int __init unknown_bootoption(char *param, char *val)
280{
281    /* Change NUL term back to "=", to make "param" the whole string. */
282    if (val) {
283        /* param=val or param="val"? */
284        if (val == param+strlen(param)+1)
285            val[-1] = '=';
286        else if (val == param+strlen(param)+2) {
287            val[-2] = '=';
288            memmove(val-1, val, strlen(val)+1);
289            val--;
290        } else
291            BUG();
292    }
293
294    /* Handle obsolete-style parameters */
295    if (obsolete_checksetup(param))
296        return 0;
297
298    /* Unused module parameter. */
299    if (strchr(param, '.') && (!val || strchr(param, '.') < val))
300        return 0;
301
302    if (panic_later)
303        return 0;
304
305    if (val) {
306        /* Environment option */
307        unsigned int i;
308        for (i = 0; envp_init[i]; i++) {
309            if (i == MAX_INIT_ENVS) {
310                panic_later = "Too many boot env vars at `%s'";
311                panic_param = param;
312            }
313            if (!strncmp(param, envp_init[i], val - param))
314                break;
315        }
316        envp_init[i] = param;
317    } else {
318        /* Command line option */
319        unsigned int i;
320        for (i = 0; argv_init[i]; i++) {
321            if (i == MAX_INIT_ARGS) {
322                panic_later = "Too many boot init vars at `%s'";
323                panic_param = param;
324            }
325        }
326        argv_init[i] = param;
327    }
328    return 0;
329}
330
331#ifdef CONFIG_DEBUG_PAGEALLOC
332int __read_mostly debug_pagealloc_enabled = 0;
333#endif
334
335static int __init init_setup(char *str)
336{
337    unsigned int i;
338
339    execute_command = str;
340    /*
341     * In case LILO is going to boot us with default command line,
342     * it prepends "auto" before the whole cmdline which makes
343     * the shell think it should execute a script with such name.
344     * So we ignore all arguments entered _before_ init=... [MJ]
345     */
346    for (i = 1; i < MAX_INIT_ARGS; i++)
347        argv_init[i] = NULL;
348    return 1;
349}
350__setup("init=", init_setup);
351
352static int __init rdinit_setup(char *str)
353{
354    unsigned int i;
355
356    ramdisk_execute_command = str;
357    /* See "auto" comment in init_setup */
358    for (i = 1; i < MAX_INIT_ARGS; i++)
359        argv_init[i] = NULL;
360    return 1;
361}
362__setup("rdinit=", rdinit_setup);
363
364#ifndef CONFIG_SMP
365
366#ifdef CONFIG_X86_LOCAL_APIC
367static void __init smp_init(void)
368{
369    APIC_init_uniprocessor();
370}
371#else
372#define smp_init() do { } while (0)
373#endif
374
375static inline void setup_nr_cpu_ids(void) { }
376static inline void smp_prepare_cpus(unsigned int maxcpus) { }
377
378#else
379
380/* Setup number of possible processor ids */
381int nr_cpu_ids __read_mostly = NR_CPUS;
382EXPORT_SYMBOL(nr_cpu_ids);
383
384/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
385static void __init setup_nr_cpu_ids(void)
386{
387    nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
388}
389
390/* Called by boot processor to activate the rest. */
391static void __init smp_init(void)
392{
393    unsigned int cpu;
394
395    /* FIXME: This should be done in userspace --RR */
396    for_each_present_cpu(cpu) {
397        if (num_online_cpus() >= setup_max_cpus)
398            break;
399        if (!cpu_online(cpu))
400            cpu_up(cpu);
401    }
402
403    /* Any cleanup work */
404    printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
405    smp_cpus_done(setup_max_cpus);
406}
407
408#endif
409
410/*
411 * We need to store the untouched command line for future reference.
412 * We also need to store the touched command line since the parameter
413 * parsing is performed in place, and we should allow a component to
414 * store reference of name/value for future reference.
415 */
416static void __init setup_command_line(char *command_line)
417{
418    saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
419    static_command_line = alloc_bootmem(strlen (command_line)+1);
420    strcpy (saved_command_line, boot_command_line);
421    strcpy (static_command_line, command_line);
422}
423
424/*
425 * We need to finalize in a non-__init function or else race conditions
426 * between the root thread and the init thread may cause start_kernel to
427 * be reaped by free_initmem before the root thread has proceeded to
428 * cpu_idle.
429 *
430 * gcc-3.4 accidentally inlines this function, so use noinline.
431 */
432
433static __initdata DECLARE_COMPLETION(kthreadd_done);
434
435static noinline void __init_refok rest_init(void)
436{
437    int pid;
438
439    rcu_scheduler_starting();
440    /*
441     * We need to spawn init first so that it obtains pid 1, however
442     * the init task will end up wanting to create kthreads, which, if
443     * we schedule it before we create kthreadd, will OOPS.
444     */
445    kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
446    numa_default_policy();
447    pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
448    rcu_read_lock();
449    kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
450    rcu_read_unlock();
451    complete(&kthreadd_done);
452
453    /*
454     * The boot idle thread must execute schedule()
455     * at least once to get things moving:
456     */
457    init_idle_bootup_task(current);
458    preempt_enable_no_resched();
459    schedule();
460    preempt_disable();
461
462    /* Call into cpu_idle with preempt disabled */
463    cpu_idle();
464}
465
466/* Check for early params. */
467static int __init do_early_param(char *param, char *val)
468{
469    const struct obs_kernel_param *p;
470
471    for (p = __setup_start; p < __setup_end; p++) {
472        if ((p->early && strcmp(param, p->str) == 0) ||
473            (strcmp(param, "console") == 0 &&
474             strcmp(p->str, "earlycon") == 0)
475        ) {
476            if (p->setup_func(val) != 0)
477                printk(KERN_WARNING
478                       "Malformed early option '%s'\n", param);
479        }
480    }
481    /* We accept everything at this stage. */
482    return 0;
483}
484
485void __init parse_early_options(char *cmdline)
486{
487    parse_args("early options", cmdline, NULL, 0, do_early_param);
488}
489
490/* Arch code calls this early on, or if not, just before other parsing. */
491void __init parse_early_param(void)
492{
493    static __initdata int done = 0;
494    static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
495
496    if (done)
497        return;
498
499    /* All fall through to do_early_param. */
500    strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
501    parse_early_options(tmp_cmdline);
502    done = 1;
503}
504
505/*
506 * Activate the first processor.
507 */
508
509static void __init boot_cpu_init(void)
510{
511    int cpu = smp_processor_id();
512    /* Mark the boot cpu "present", "online" etc for SMP and UP case */
513    set_cpu_online(cpu, true);
514    set_cpu_active(cpu, true);
515    set_cpu_present(cpu, true);
516    set_cpu_possible(cpu, true);
517}
518
519void __init __weak smp_setup_processor_id(void)
520{
521}
522
523void __init __weak thread_info_cache_init(void)
524{
525}
526
527/*
528 * Set up kernel memory allocators
529 */
530static void __init mm_init(void)
531{
532    /*
533     * page_cgroup requires countinous pages as memmap
534     * and it's bigger than MAX_ORDER unless SPARSEMEM.
535     */
536    page_cgroup_init_flatmem();
537    mem_init();
538    kmem_cache_init();
539    percpu_init_late();
540    pgtable_cache_init();
541    vmalloc_init();
542}
543
544asmlinkage void __init start_kernel(void)
545{
546    char * command_line;
547    extern const struct kernel_param __start___param[], __stop___param[];
548
549    smp_setup_processor_id();
550
551    /*
552     * Need to run as early as possible, to initialize the
553     * lockdep hash:
554     */
555    lockdep_init();
556    debug_objects_early_init();
557
558    /*
559     * Set up the the initial canary ASAP:
560     */
561    boot_init_stack_canary();
562
563    cgroup_init_early();
564
565    local_irq_disable();
566    early_boot_irqs_disabled = true;
567
568/*
569 * Interrupts are still disabled. Do necessary setups, then
570 * enable them
571 */
572    tick_init();
573    boot_cpu_init();
574    page_address_init();
575    printk(KERN_NOTICE "%s", linux_banner);
576    setup_arch(&command_line);
577    mm_init_owner(&init_mm, &init_task);
578    setup_command_line(command_line);
579    setup_nr_cpu_ids();
580    setup_per_cpu_areas();
581    smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
582
583    build_all_zonelists(NULL);
584    page_alloc_init();
585
586    printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
587    parse_early_param();
588    parse_args("Booting kernel", static_command_line, __start___param,
589           __stop___param - __start___param,
590           &unknown_bootoption);
591    /*
592     * These use large bootmem allocations and must precede
593     * kmem_cache_init()
594     */
595    pidhash_init();
596    vfs_caches_init_early();
597    sort_main_extable();
598    trap_init();
599    mm_init();
600    /*
601     * Set up the scheduler prior starting any interrupts (such as the
602     * timer interrupt). Full topology setup happens at smp_init()
603     * time - but meanwhile we still have a functioning scheduler.
604     */
605    sched_init();
606    /*
607     * Disable preemption - early bootup scheduling is extremely
608     * fragile until we cpu_idle() for the first time.
609     */
610    preempt_disable();
611    if (!irqs_disabled()) {
612        printk(KERN_WARNING "start_kernel(): bug: interrupts were "
613                "enabled *very* early, fixing it\n");
614        local_irq_disable();
615    }
616    idr_init_cache();
617    perf_event_init();
618    rcu_init();
619    radix_tree_init();
620    /* init some links before init_ISA_irqs() */
621    early_irq_init();
622    init_IRQ();
623    prio_tree_init();
624    init_timers();
625    hrtimers_init();
626    softirq_init();
627    timekeeping_init();
628    time_init();
629    profile_init();
630    if (!irqs_disabled())
631        printk(KERN_CRIT "start_kernel(): bug: interrupts were "
632                 "enabled early\n");
633    early_boot_irqs_disabled = false;
634    local_irq_enable();
635
636    /* Interrupts are enabled now so all GFP allocations are safe. */
637    gfp_allowed_mask = __GFP_BITS_MASK;
638
639    kmem_cache_init_late();
640
641    /*
642     * HACK ALERT! This is early. We're enabling the console before
643     * we've done PCI setups etc, and console_init() must be aware of
644     * this. But we do want output early, in case something goes wrong.
645     */
646    console_init();
647    if (panic_later)
648        panic(panic_later, panic_param);
649
650    lockdep_info();
651
652    /*
653     * Need to run this when irqs are enabled, because it wants
654     * to self-test [hard/soft]-irqs on/off lock inversion bugs
655     * too:
656     */
657    locking_selftest();
658
659#ifdef CONFIG_BLK_DEV_INITRD
660    if (initrd_start && !initrd_below_start_ok &&
661        page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
662        printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
663            "disabling it.\n",
664            page_to_pfn(virt_to_page((void *)initrd_start)),
665            min_low_pfn);
666        initrd_start = 0;
667    }
668#endif
669    page_cgroup_init();
670    enable_debug_pagealloc();
671    kmemleak_init();
672    debug_objects_mem_init();
673    setup_per_cpu_pageset();
674    numa_policy_init();
675    if (late_time_init)
676        late_time_init();
677    sched_clock_init();
678    calibrate_delay();
679    pidmap_init();
680    anon_vma_init();
681#ifdef CONFIG_X86
682    if (efi_enabled)
683        efi_enter_virtual_mode();
684#endif
685    thread_info_cache_init();
686    cred_init();
687    fork_init(totalram_pages);
688    proc_caches_init();
689    buffer_init();
690    key_init();
691    security_init();
692    dbg_late_init();
693    vfs_caches_init(totalram_pages);
694    signals_init();
695    /* rootfs populating might need page-writeback */
696    page_writeback_init();
697#ifdef CONFIG_PROC_FS
698    proc_root_init();
699#endif
700    cgroup_init();
701    cpuset_init();
702    taskstats_init_early();
703    delayacct_init();
704
705    check_bugs();
706
707    acpi_early_init(); /* before LAPIC and SMP init */
708    sfi_init_late();
709
710    ftrace_init();
711
712    /* Do the rest non-__init'ed, we're now alive */
713    rest_init();
714}
715
716/* Call all constructor functions linked into the kernel. */
717static void __init do_ctors(void)
718{
719#ifdef CONFIG_CONSTRUCTORS
720    ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
721
722    for (; fn < (ctor_fn_t *) __ctors_end; fn++)
723        (*fn)();
724#endif
725}
726
727int initcall_debug;
728core_param(initcall_debug, initcall_debug, bool, 0644);
729
730static char msgbuf[64];
731
732static int __init_or_module do_one_initcall_debug(initcall_t fn)
733{
734    ktime_t calltime, delta, rettime;
735    unsigned long long duration;
736    int ret;
737
738    printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
739    calltime = ktime_get();
740    ret = fn();
741    rettime = ktime_get();
742    delta = ktime_sub(rettime, calltime);
743    duration = (unsigned long long) ktime_to_ns(delta) >> 10;
744    printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
745        ret, duration);
746
747    return ret;
748}
749
750int __init_or_module do_one_initcall(initcall_t fn)
751{
752    int count = preempt_count();
753    int ret;
754
755    if (initcall_debug)
756        ret = do_one_initcall_debug(fn);
757    else
758        ret = fn();
759
760    msgbuf[0] = 0;
761
762    if (ret && ret != -ENODEV && initcall_debug)
763        sprintf(msgbuf, "error code %d ", ret);
764
765    if (preempt_count() != count) {
766        strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
767        preempt_count() = count;
768    }
769    if (irqs_disabled()) {
770        strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
771        local_irq_enable();
772    }
773    if (msgbuf[0]) {
774        printk("initcall %pF returned with %s\n", fn, msgbuf);
775    }
776
777    return ret;
778}
779
780
781extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
782
783static void __init do_initcalls(void)
784{
785    initcall_t *fn;
786
787    for (fn = __early_initcall_end; fn < __initcall_end; fn++)
788        do_one_initcall(*fn);
789}
790
791/*
792 * Ok, the machine is now initialized. None of the devices
793 * have been touched yet, but the CPU subsystem is up and
794 * running, and memory and process management works.
795 *
796 * Now we can finally start doing some real work..
797 */
798static void __init do_basic_setup(void)
799{
800    cpuset_init_smp();
801    usermodehelper_init();
802    init_tmpfs();
803    driver_init();
804    init_irq_proc();
805    do_ctors();
806    do_initcalls();
807}
808
809static void __init do_pre_smp_initcalls(void)
810{
811    initcall_t *fn;
812
813    for (fn = __initcall_start; fn < __early_initcall_end; fn++)
814        do_one_initcall(*fn);
815}
816
817static void run_init_process(const char *init_filename)
818{
819    argv_init[0] = init_filename;
820    kernel_execve(init_filename, argv_init, envp_init);
821}
822
823/* This is a non __init function. Force it to be noinline otherwise gcc
824 * makes it inline to init() and it becomes part of init.text section
825 */
826static noinline int init_post(void)
827{
828    /* need to finish all async __init code before freeing the memory */
829    async_synchronize_full();
830    free_initmem();
831    mark_rodata_ro();
832    system_state = SYSTEM_RUNNING;
833    numa_default_policy();
834
835
836    current->signal->flags |= SIGNAL_UNKILLABLE;
837
838    if (ramdisk_execute_command) {
839        run_init_process(ramdisk_execute_command);
840        printk(KERN_WARNING "Failed to execute %s\n",
841                ramdisk_execute_command);
842    }
843
844    /*
845     * We try each of these until one succeeds.
846     *
847     * The Bourne shell can be used instead of init if we are
848     * trying to recover a really broken machine.
849     */
850    if (execute_command) {
851        run_init_process(execute_command);
852        printk(KERN_WARNING "Failed to execute %s. Attempting "
853                    "defaults...\n", execute_command);
854    }
855    run_init_process("/etc/preinit");
856    run_init_process("/sbin/init");
857    run_init_process("/etc/init");
858    run_init_process("/bin/init");
859    run_init_process("/bin/sh");
860
861    panic("No init found. Try passing init= option to kernel. "
862          "See Linux Documentation/init.txt for guidance.");
863}
864
865static int __init kernel_init(void * unused)
866{
867    /*
868     * Wait until kthreadd is all set-up.
869     */
870    wait_for_completion(&kthreadd_done);
871    /*
872     * init can allocate pages on any node
873     */
874    set_mems_allowed(node_states[N_HIGH_MEMORY]);
875    /*
876     * init can run on any cpu.
877     */
878    set_cpus_allowed_ptr(current, cpu_all_mask);
879    /*
880     * Tell the world that we're going to be the grim
881     * reaper of innocent orphaned children.
882     *
883     * We don't want people to have to make incorrect
884     * assumptions about where in the task array this
885     * can be found.
886     */
887    init_pid_ns.child_reaper = current;
888
889    cad_pid = task_pid(current);
890
891    smp_prepare_cpus(setup_max_cpus);
892
893    do_pre_smp_initcalls();
894    lockup_detector_init();
895
896    smp_init();
897    sched_init_smp();
898
899    do_basic_setup();
900
901    /* Open the /dev/console on the rootfs, this should never fail */
902    if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
903        printk(KERN_WARNING "Warning: unable to open an initial console.\n");
904
905    (void) sys_dup(0);
906    (void) sys_dup(0);
907    /*
908     * check if there is an early userspace init. If yes, let it do all
909     * the work
910     */
911
912    if (!ramdisk_execute_command)
913        ramdisk_execute_command = "/init";
914
915    if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
916        ramdisk_execute_command = NULL;
917        prepare_namespace();
918    }
919
920    /*
921     * Ok, we have completed the initial bootup, and
922     * we're essentially up and running. Get rid of the
923     * initmem segments and start the user-mode stuff..
924     */
925
926    init_post();
927    return 0;
928}
929

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