linux/init/main.c
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   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#include <linux/file.h>
  72
  73#include <asm/io.h>
  74#include <asm/bugs.h>
  75#include <asm/setup.h>
  76#include <asm/sections.h>
  77#include <asm/cacheflush.h>
  78
  79#ifdef CONFIG_X86_LOCAL_APIC
  80#include <asm/smp.h>
  81#endif
  82
  83static int kernel_init(void *);
  84
  85extern void init_IRQ(void);
  86extern void fork_init(unsigned long);
  87extern void mca_init(void);
  88extern void sbus_init(void);
  89extern void prio_tree_init(void);
  90extern void radix_tree_init(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/*
 133 * If set, this is an indication to the drivers that reset the underlying
 134 * device before going ahead with the initialization otherwise driver might
 135 * rely on the BIOS and skip the reset operation.
 136 *
 137 * This is useful if kernel is booting in an unreliable environment.
 138 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 139 * skipped and devices will be in unknown state.
 140 */
 141unsigned int reset_devices;
 142EXPORT_SYMBOL(reset_devices);
 143
 144static int __init set_reset_devices(char *str)
 145{
 146        reset_devices = 1;
 147        return 1;
 148}
 149
 150__setup("reset_devices", set_reset_devices);
 151
 152static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 153const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 154static const char *panic_later, *panic_param;
 155
 156extern const struct obs_kernel_param __setup_start[], __setup_end[];
 157
 158static int __init obsolete_checksetup(char *line)
 159{
 160        const struct obs_kernel_param *p;
 161        int had_early_param = 0;
 162
 163        p = __setup_start;
 164        do {
 165                int n = strlen(p->str);
 166                if (parameqn(line, p->str, n)) {
 167                        if (p->early) {
 168                                /* Already done in parse_early_param?
 169                                 * (Needs exact match on param part).
 170                                 * Keep iterating, as we can have early
 171                                 * params and __setups of same names 8( */
 172                                if (line[n] == '\0' || line[n] == '=')
 173                                        had_early_param = 1;
 174                        } else if (!p->setup_func) {
 175                                printk(KERN_WARNING "Parameter %s is obsolete,"
 176                                       " ignored\n", p->str);
 177                                return 1;
 178                        } else if (p->setup_func(line + n))
 179                                return 1;
 180                }
 181                p++;
 182        } while (p < __setup_end);
 183
 184        return had_early_param;
 185}
 186
 187/*
 188 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 189 * still work even if initially too large, it will just take slightly longer
 190 */
 191unsigned long loops_per_jiffy = (1<<12);
 192
 193EXPORT_SYMBOL(loops_per_jiffy);
 194
 195static int __init debug_kernel(char *str)
 196{
 197        console_loglevel = 10;
 198        return 0;
 199}
 200
 201static int __init quiet_kernel(char *str)
 202{
 203        console_loglevel = 4;
 204        return 0;
 205}
 206
 207early_param("debug", debug_kernel);
 208early_param("quiet", quiet_kernel);
 209
 210static int __init loglevel(char *str)
 211{
 212        int newlevel;
 213
 214        /*
 215         * Only update loglevel value when a correct setting was passed,
 216         * to prevent blind crashes (when loglevel being set to 0) that
 217         * are quite hard to debug
 218         */
 219        if (get_option(&str, &newlevel)) {
 220                console_loglevel = newlevel;
 221                return 0;
 222        }
 223
 224        return -EINVAL;
 225}
 226
 227early_param("loglevel", loglevel);
 228
 229/* Change NUL term back to "=", to make "param" the whole string. */
 230static int __init repair_env_string(char *param, char *val, const char *unused)
 231{
 232        if (val) {
 233                /* param=val or param="val"? */
 234                if (val == param+strlen(param)+1)
 235                        val[-1] = '=';
 236                else if (val == param+strlen(param)+2) {
 237                        val[-2] = '=';
 238                        memmove(val-1, val, strlen(val)+1);
 239                        val--;
 240                } else
 241                        BUG();
 242        }
 243        return 0;
 244}
 245
 246/*
 247 * Unknown boot options get handed to init, unless they look like
 248 * unused parameters (modprobe will find them in /proc/cmdline).
 249 */
 250static int __init unknown_bootoption(char *param, char *val, const char *unused)
 251{
 252        repair_env_string(param, val, unused);
 253
 254        /* Handle obsolete-style parameters */
 255        if (obsolete_checksetup(param))
 256                return 0;
 257
 258        /* Unused module parameter. */
 259        if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 260                return 0;
 261
 262        if (panic_later)
 263                return 0;
 264
 265        if (val) {
 266                /* Environment option */
 267                unsigned int i;
 268                for (i = 0; envp_init[i]; i++) {
 269                        if (i == MAX_INIT_ENVS) {
 270                                panic_later = "Too many boot env vars at `%s'";
 271                                panic_param = param;
 272                        }
 273                        if (!strncmp(param, envp_init[i], val - param))
 274                                break;
 275                }
 276                envp_init[i] = param;
 277        } else {
 278                /* Command line option */
 279                unsigned int i;
 280                for (i = 0; argv_init[i]; i++) {
 281                        if (i == MAX_INIT_ARGS) {
 282                                panic_later = "Too many boot init vars at `%s'";
 283                                panic_param = param;
 284                        }
 285                }
 286                argv_init[i] = param;
 287        }
 288        return 0;
 289}
 290
 291static int __init init_setup(char *str)
 292{
 293        unsigned int i;
 294
 295        execute_command = str;
 296        /*
 297         * In case LILO is going to boot us with default command line,
 298         * it prepends "auto" before the whole cmdline which makes
 299         * the shell think it should execute a script with such name.
 300         * So we ignore all arguments entered _before_ init=... [MJ]
 301         */
 302        for (i = 1; i < MAX_INIT_ARGS; i++)
 303                argv_init[i] = NULL;
 304        return 1;
 305}
 306__setup("init=", init_setup);
 307
 308static int __init rdinit_setup(char *str)
 309{
 310        unsigned int i;
 311
 312        ramdisk_execute_command = str;
 313        /* See "auto" comment in init_setup */
 314        for (i = 1; i < MAX_INIT_ARGS; i++)
 315                argv_init[i] = NULL;
 316        return 1;
 317}
 318__setup("rdinit=", rdinit_setup);
 319
 320#ifndef CONFIG_SMP
 321static const unsigned int setup_max_cpus = NR_CPUS;
 322#ifdef CONFIG_X86_LOCAL_APIC
 323static void __init smp_init(void)
 324{
 325        APIC_init_uniprocessor();
 326}
 327#else
 328#define smp_init()      do { } while (0)
 329#endif
 330
 331static inline void setup_nr_cpu_ids(void) { }
 332static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 333#endif
 334
 335/*
 336 * We need to store the untouched command line for future reference.
 337 * We also need to store the touched command line since the parameter
 338 * parsing is performed in place, and we should allow a component to
 339 * store reference of name/value for future reference.
 340 */
 341static void __init setup_command_line(char *command_line)
 342{
 343        saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 344        static_command_line = alloc_bootmem(strlen (command_line)+1);
 345        strcpy (saved_command_line, boot_command_line);
 346        strcpy (static_command_line, command_line);
 347}
 348
 349/*
 350 * We need to finalize in a non-__init function or else race conditions
 351 * between the root thread and the init thread may cause start_kernel to
 352 * be reaped by free_initmem before the root thread has proceeded to
 353 * cpu_idle.
 354 *
 355 * gcc-3.4 accidentally inlines this function, so use noinline.
 356 */
 357
 358static __initdata DECLARE_COMPLETION(kthreadd_done);
 359
 360static noinline void __init_refok rest_init(void)
 361{
 362        int pid;
 363
 364        rcu_scheduler_starting();
 365        /*
 366         * We need to spawn init first so that it obtains pid 1, however
 367         * the init task will end up wanting to create kthreads, which, if
 368         * we schedule it before we create kthreadd, will OOPS.
 369         */
 370        kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 371        numa_default_policy();
 372        pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 373        rcu_read_lock();
 374        kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 375        rcu_read_unlock();
 376        complete(&kthreadd_done);
 377
 378        /*
 379         * The boot idle thread must execute schedule()
 380         * at least once to get things moving:
 381         */
 382        init_idle_bootup_task(current);
 383        schedule_preempt_disabled();
 384        /* Call into cpu_idle with preempt disabled */
 385        cpu_idle();
 386}
 387
 388/* Check for early params. */
 389static int __init do_early_param(char *param, char *val, const char *unused)
 390{
 391        const struct obs_kernel_param *p;
 392
 393        for (p = __setup_start; p < __setup_end; p++) {
 394                if ((p->early && parameq(param, p->str)) ||
 395                    (strcmp(param, "console") == 0 &&
 396                     strcmp(p->str, "earlycon") == 0)
 397                ) {
 398                        if (p->setup_func(val) != 0)
 399                                printk(KERN_WARNING
 400                                       "Malformed early option '%s'\n", param);
 401                }
 402        }
 403        /* We accept everything at this stage. */
 404        return 0;
 405}
 406
 407void __init parse_early_options(char *cmdline)
 408{
 409        parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 410}
 411
 412/* Arch code calls this early on, or if not, just before other parsing. */
 413void __init parse_early_param(void)
 414{
 415        static __initdata int done = 0;
 416        static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 417
 418        if (done)
 419                return;
 420
 421        /* All fall through to do_early_param. */
 422        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 423        parse_early_options(tmp_cmdline);
 424        done = 1;
 425}
 426
 427/*
 428 *      Activate the first processor.
 429 */
 430
 431static void __init boot_cpu_init(void)
 432{
 433        int cpu = smp_processor_id();
 434        /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 435        set_cpu_online(cpu, true);
 436        set_cpu_active(cpu, true);
 437        set_cpu_present(cpu, true);
 438        set_cpu_possible(cpu, true);
 439}
 440
 441void __init __weak smp_setup_processor_id(void)
 442{
 443}
 444
 445void __init __weak thread_info_cache_init(void)
 446{
 447}
 448
 449/*
 450 * Set up kernel memory allocators
 451 */
 452static void __init mm_init(void)
 453{
 454        /*
 455         * page_cgroup requires contiguous pages,
 456         * bigger than MAX_ORDER unless SPARSEMEM.
 457         */
 458        page_cgroup_init_flatmem();
 459        mem_init();
 460        kmem_cache_init();
 461        percpu_init_late();
 462        pgtable_cache_init();
 463        vmalloc_init();
 464}
 465
 466asmlinkage void __init start_kernel(void)
 467{
 468        char * command_line;
 469        extern const struct kernel_param __start___param[], __stop___param[];
 470
 471        /*
 472         * Need to run as early as possible, to initialize the
 473         * lockdep hash:
 474         */
 475        lockdep_init();
 476        smp_setup_processor_id();
 477        debug_objects_early_init();
 478
 479        /*
 480         * Set up the the initial canary ASAP:
 481         */
 482        boot_init_stack_canary();
 483
 484        cgroup_init_early();
 485
 486        local_irq_disable();
 487        early_boot_irqs_disabled = true;
 488
 489/*
 490 * Interrupts are still disabled. Do necessary setups, then
 491 * enable them
 492 */
 493        tick_init();
 494        boot_cpu_init();
 495        page_address_init();
 496        printk(KERN_NOTICE "%s", linux_banner);
 497        setup_arch(&command_line);
 498        mm_init_owner(&init_mm, &init_task);
 499        mm_init_cpumask(&init_mm);
 500        setup_command_line(command_line);
 501        setup_nr_cpu_ids();
 502        setup_per_cpu_areas();
 503        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 504
 505        build_all_zonelists(NULL, NULL);
 506        page_alloc_init();
 507
 508        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 509        parse_early_param();
 510        parse_args("Booting kernel", static_command_line, __start___param,
 511                   __stop___param - __start___param,
 512                   -1, -1, &unknown_bootoption);
 513
 514        jump_label_init();
 515
 516        /*
 517         * These use large bootmem allocations and must precede
 518         * kmem_cache_init()
 519         */
 520        setup_log_buf(0);
 521        pidhash_init();
 522        vfs_caches_init_early();
 523        sort_main_extable();
 524        trap_init();
 525        mm_init();
 526
 527        /*
 528         * Set up the scheduler prior starting any interrupts (such as the
 529         * timer interrupt). Full topology setup happens at smp_init()
 530         * time - but meanwhile we still have a functioning scheduler.
 531         */
 532        sched_init();
 533        /*
 534         * Disable preemption - early bootup scheduling is extremely
 535         * fragile until we cpu_idle() for the first time.
 536         */
 537        preempt_disable();
 538        if (!irqs_disabled()) {
 539                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 540                                "enabled *very* early, fixing it\n");
 541                local_irq_disable();
 542        }
 543        idr_init_cache();
 544        perf_event_init();
 545        rcu_init();
 546        radix_tree_init();
 547        /* init some links before init_ISA_irqs() */
 548        early_irq_init();
 549        init_IRQ();
 550        prio_tree_init();
 551        init_timers();
 552        hrtimers_init();
 553        softirq_init();
 554        timekeeping_init();
 555        time_init();
 556        profile_init();
 557        call_function_init();
 558        if (!irqs_disabled())
 559                printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 560                                 "enabled early\n");
 561        early_boot_irqs_disabled = false;
 562        local_irq_enable();
 563
 564        kmem_cache_init_late();
 565
 566        /*
 567         * HACK ALERT! This is early. We're enabling the console before
 568         * we've done PCI setups etc, and console_init() must be aware of
 569         * this. But we do want output early, in case something goes wrong.
 570         */
 571        console_init();
 572        if (panic_later)
 573                panic(panic_later, panic_param);
 574
 575        lockdep_info();
 576
 577        /*
 578         * Need to run this when irqs are enabled, because it wants
 579         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 580         * too:
 581         */
 582        locking_selftest();
 583
 584#ifdef CONFIG_BLK_DEV_INITRD
 585        if (initrd_start && !initrd_below_start_ok &&
 586            page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 587                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 588                    "disabling it.\n",
 589                    page_to_pfn(virt_to_page((void *)initrd_start)),
 590                    min_low_pfn);
 591                initrd_start = 0;
 592        }
 593#endif
 594        page_cgroup_init();
 595        debug_objects_mem_init();
 596        kmemleak_init();
 597        setup_per_cpu_pageset();
 598        numa_policy_init();
 599        if (late_time_init)
 600                late_time_init();
 601        sched_clock_init();
 602        calibrate_delay();
 603        pidmap_init();
 604        anon_vma_init();
 605#ifdef CONFIG_X86
 606        if (efi_enabled)
 607                efi_enter_virtual_mode();
 608#endif
 609        thread_info_cache_init();
 610        cred_init();
 611        fork_init(totalram_pages);
 612        proc_caches_init();
 613        buffer_init();
 614        key_init();
 615        security_init();
 616        dbg_late_init();
 617        vfs_caches_init(totalram_pages);
 618        signals_init();
 619        /* rootfs populating might need page-writeback */
 620        page_writeback_init();
 621#ifdef CONFIG_PROC_FS
 622        proc_root_init();
 623#endif
 624        cgroup_init();
 625        cpuset_init();
 626        taskstats_init_early();
 627        delayacct_init();
 628
 629        check_bugs();
 630
 631        acpi_early_init(); /* before LAPIC and SMP init */
 632        sfi_init_late();
 633
 634        if (efi_enabled)
 635                efi_free_boot_services();
 636
 637        ftrace_init();
 638
 639        /* Do the rest non-__init'ed, we're now alive */
 640        rest_init();
 641}
 642
 643/* Call all constructor functions linked into the kernel. */
 644static void __init do_ctors(void)
 645{
 646#ifdef CONFIG_CONSTRUCTORS
 647        ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 648
 649        for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 650                (*fn)();
 651#endif
 652}
 653
 654bool initcall_debug;
 655core_param(initcall_debug, initcall_debug, bool, 0644);
 656
 657static char msgbuf[64];
 658
 659static int __init_or_module do_one_initcall_debug(initcall_t fn)
 660{
 661        ktime_t calltime, delta, rettime;
 662        unsigned long long duration;
 663        int ret;
 664
 665        printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 666        calltime = ktime_get();
 667        ret = fn();
 668        rettime = ktime_get();
 669        delta = ktime_sub(rettime, calltime);
 670        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 671        printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 672                ret, duration);
 673
 674        return ret;
 675}
 676
 677int __init_or_module do_one_initcall(initcall_t fn)
 678{
 679        int count = preempt_count();
 680        int ret;
 681
 682        if (initcall_debug)
 683                ret = do_one_initcall_debug(fn);
 684        else
 685                ret = fn();
 686
 687        msgbuf[0] = 0;
 688
 689        if (ret && ret != -ENODEV && initcall_debug)
 690                sprintf(msgbuf, "error code %d ", ret);
 691
 692        if (preempt_count() != count) {
 693                strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 694                preempt_count() = count;
 695        }
 696        if (irqs_disabled()) {
 697                strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 698                local_irq_enable();
 699        }
 700        if (msgbuf[0]) {
 701                printk("initcall %pF returned with %s\n", fn, msgbuf);
 702        }
 703
 704        return ret;
 705}
 706
 707
 708extern initcall_t __initcall_start[];
 709extern initcall_t __initcall0_start[];
 710extern initcall_t __initcall1_start[];
 711extern initcall_t __initcall2_start[];
 712extern initcall_t __initcall3_start[];
 713extern initcall_t __initcall4_start[];
 714extern initcall_t __initcall5_start[];
 715extern initcall_t __initcall6_start[];
 716extern initcall_t __initcall7_start[];
 717extern initcall_t __initcall_end[];
 718
 719static initcall_t *initcall_levels[] __initdata = {
 720        __initcall0_start,
 721        __initcall1_start,
 722        __initcall2_start,
 723        __initcall3_start,
 724        __initcall4_start,
 725        __initcall5_start,
 726        __initcall6_start,
 727        __initcall7_start,
 728        __initcall_end,
 729};
 730
 731/* Keep these in sync with initcalls in include/linux/init.h */
 732static char *initcall_level_names[] __initdata = {
 733        "early",
 734        "core",
 735        "postcore",
 736        "arch",
 737        "subsys",
 738        "fs",
 739        "device",
 740        "late",
 741};
 742
 743static void __init do_initcall_level(int level)
 744{
 745        extern const struct kernel_param __start___param[], __stop___param[];
 746        initcall_t *fn;
 747
 748        strcpy(static_command_line, saved_command_line);
 749        parse_args(initcall_level_names[level],
 750                   static_command_line, __start___param,
 751                   __stop___param - __start___param,
 752                   level, level,
 753                   &repair_env_string);
 754
 755        for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 756                do_one_initcall(*fn);
 757}
 758
 759static void __init do_initcalls(void)
 760{
 761        int level;
 762
 763        for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 764                do_initcall_level(level);
 765}
 766
 767/*
 768 * Ok, the machine is now initialized. None of the devices
 769 * have been touched yet, but the CPU subsystem is up and
 770 * running, and memory and process management works.
 771 *
 772 * Now we can finally start doing some real work..
 773 */
 774static void __init do_basic_setup(void)
 775{
 776        cpuset_init_smp();
 777        usermodehelper_init();
 778        shmem_init();
 779        driver_init();
 780        init_irq_proc();
 781        do_ctors();
 782        usermodehelper_enable();
 783        do_initcalls();
 784}
 785
 786static void __init do_pre_smp_initcalls(void)
 787{
 788        initcall_t *fn;
 789
 790        for (fn = __initcall_start; fn < __initcall0_start; fn++)
 791                do_one_initcall(*fn);
 792}
 793
 794static void run_init_process(const char *init_filename)
 795{
 796        argv_init[0] = init_filename;
 797        kernel_execve(init_filename, argv_init, envp_init);
 798}
 799
 800/* This is a non __init function. Force it to be noinline otherwise gcc
 801 * makes it inline to init() and it becomes part of init.text section
 802 */
 803static noinline int init_post(void)
 804{
 805        /* need to finish all async __init code before freeing the memory */
 806        async_synchronize_full();
 807        free_initmem();
 808        mark_rodata_ro();
 809        system_state = SYSTEM_RUNNING;
 810        numa_default_policy();
 811
 812        current->signal->flags |= SIGNAL_UNKILLABLE;
 813        flush_delayed_fput();
 814
 815        if (ramdisk_execute_command) {
 816                run_init_process(ramdisk_execute_command);
 817                printk(KERN_WARNING "Failed to execute %s\n",
 818                                ramdisk_execute_command);
 819        }
 820
 821        /*
 822         * We try each of these until one succeeds.
 823         *
 824         * The Bourne shell can be used instead of init if we are
 825         * trying to recover a really broken machine.
 826         */
 827        if (execute_command) {
 828                run_init_process(execute_command);
 829                printk(KERN_WARNING "Failed to execute %s.  Attempting "
 830                                        "defaults...\n", execute_command);
 831        }
 832        run_init_process("/sbin/init");
 833        run_init_process("/etc/init");
 834        run_init_process("/bin/init");
 835        run_init_process("/bin/sh");
 836
 837        panic("No init found.  Try passing init= option to kernel. "
 838              "See Linux Documentation/init.txt for guidance.");
 839}
 840
 841static int __init kernel_init(void * unused)
 842{
 843        /*
 844         * Wait until kthreadd is all set-up.
 845         */
 846        wait_for_completion(&kthreadd_done);
 847
 848        /* Now the scheduler is fully set up and can do blocking allocations */
 849        gfp_allowed_mask = __GFP_BITS_MASK;
 850
 851        /*
 852         * init can allocate pages on any node
 853         */
 854        set_mems_allowed(node_states[N_HIGH_MEMORY]);
 855        /*
 856         * init can run on any cpu.
 857         */
 858        set_cpus_allowed_ptr(current, cpu_all_mask);
 859
 860        cad_pid = task_pid(current);
 861
 862        smp_prepare_cpus(setup_max_cpus);
 863
 864        do_pre_smp_initcalls();
 865        lockup_detector_init();
 866
 867        smp_init();
 868        sched_init_smp();
 869
 870        do_basic_setup();
 871
 872        /* Open the /dev/console on the rootfs, this should never fail */
 873        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 874                printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 875
 876        (void) sys_dup(0);
 877        (void) sys_dup(0);
 878        /*
 879         * check if there is an early userspace init.  If yes, let it do all
 880         * the work
 881         */
 882
 883        if (!ramdisk_execute_command)
 884                ramdisk_execute_command = "/init";
 885
 886        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 887                ramdisk_execute_command = NULL;
 888                prepare_namespace();
 889        }
 890
 891        /*
 892         * Ok, we have completed the initial bootup, and
 893         * we're essentially up and running. Get rid of the
 894         * initmem segments and start the user-mode stuff..
 895         */
 896
 897        init_post();
 898        return 0;
 899}
 900
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