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#include <linux/ptrace.h>
  73
  74#include <asm/io.h>
  75#include <asm/bugs.h>
  76#include <asm/setup.h>
  77#include <asm/sections.h>
  78#include <asm/cacheflush.h>
  79
  80#ifdef CONFIG_X86_LOCAL_APIC
  81#include <asm/smp.h>
  82#endif
  83
  84static int kernel_init(void *);
  85
  86extern void init_IRQ(void);
  87extern void fork_init(unsigned long);
  88extern void mca_init(void);
  89extern void sbus_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
 445# if THREAD_SIZE >= PAGE_SIZE
 446void __init __weak thread_info_cache_init(void)
 447{
 448}
 449#endif
 450
 451/*
 452 * Set up kernel memory allocators
 453 */
 454static void __init mm_init(void)
 455{
 456        /*
 457         * page_cgroup requires contiguous pages,
 458         * bigger than MAX_ORDER unless SPARSEMEM.
 459         */
 460        page_cgroup_init_flatmem();
 461        mem_init();
 462        kmem_cache_init();
 463        percpu_init_late();
 464        pgtable_cache_init();
 465        vmalloc_init();
 466}
 467
 468asmlinkage void __init start_kernel(void)
 469{
 470        char * command_line;
 471        extern const struct kernel_param __start___param[], __stop___param[];
 472
 473        /*
 474         * Need to run as early as possible, to initialize the
 475         * lockdep hash:
 476         */
 477        lockdep_init();
 478        smp_setup_processor_id();
 479        debug_objects_early_init();
 480
 481        /*
 482         * Set up the the initial canary ASAP:
 483         */
 484        boot_init_stack_canary();
 485
 486        cgroup_init_early();
 487
 488        local_irq_disable();
 489        early_boot_irqs_disabled = true;
 490
 491/*
 492 * Interrupts are still disabled. Do necessary setups, then
 493 * enable them
 494 */
 495        tick_init();
 496        boot_cpu_init();
 497        page_address_init();
 498        printk(KERN_NOTICE "%s", linux_banner);
 499        setup_arch(&command_line);
 500        mm_init_owner(&init_mm, &init_task);
 501        mm_init_cpumask(&init_mm);
 502        setup_command_line(command_line);
 503        setup_nr_cpu_ids();
 504        setup_per_cpu_areas();
 505        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 506
 507        build_all_zonelists(NULL, NULL);
 508        page_alloc_init();
 509
 510        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 511        parse_early_param();
 512        parse_args("Booting kernel", static_command_line, __start___param,
 513                   __stop___param - __start___param,
 514                   -1, -1, &unknown_bootoption);
 515
 516        jump_label_init();
 517
 518        /*
 519         * These use large bootmem allocations and must precede
 520         * kmem_cache_init()
 521         */
 522        setup_log_buf(0);
 523        pidhash_init();
 524        vfs_caches_init_early();
 525        sort_main_extable();
 526        trap_init();
 527        mm_init();
 528
 529        /*
 530         * Set up the scheduler prior starting any interrupts (such as the
 531         * timer interrupt). Full topology setup happens at smp_init()
 532         * time - but meanwhile we still have a functioning scheduler.
 533         */
 534        sched_init();
 535        /*
 536         * Disable preemption - early bootup scheduling is extremely
 537         * fragile until we cpu_idle() for the first time.
 538         */
 539        preempt_disable();
 540        if (!irqs_disabled()) {
 541                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 542                                "enabled *very* early, fixing it\n");
 543                local_irq_disable();
 544        }
 545        idr_init_cache();
 546        perf_event_init();
 547        rcu_init();
 548        radix_tree_init();
 549        /* init some links before init_ISA_irqs() */
 550        early_irq_init();
 551        init_IRQ();
 552        init_timers();
 553        hrtimers_init();
 554        softirq_init();
 555        timekeeping_init();
 556        time_init();
 557        profile_init();
 558        call_function_init();
 559        if (!irqs_disabled())
 560                printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 561                                 "enabled early\n");
 562        early_boot_irqs_disabled = false;
 563        local_irq_enable();
 564
 565        kmem_cache_init_late();
 566
 567        /*
 568         * HACK ALERT! This is early. We're enabling the console before
 569         * we've done PCI setups etc, and console_init() must be aware of
 570         * this. But we do want output early, in case something goes wrong.
 571         */
 572        console_init();
 573        if (panic_later)
 574                panic(panic_later, panic_param);
 575
 576        lockdep_info();
 577
 578        /*
 579         * Need to run this when irqs are enabled, because it wants
 580         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 581         * too:
 582         */
 583        locking_selftest();
 584
 585#ifdef CONFIG_BLK_DEV_INITRD
 586        if (initrd_start && !initrd_below_start_ok &&
 587            page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 588                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 589                    "disabling it.\n",
 590                    page_to_pfn(virt_to_page((void *)initrd_start)),
 591                    min_low_pfn);
 592                initrd_start = 0;
 593        }
 594#endif
 595        page_cgroup_init();
 596        debug_objects_mem_init();
 597        kmemleak_init();
 598        setup_per_cpu_pageset();
 599        numa_policy_init();
 600        if (late_time_init)
 601                late_time_init();
 602        sched_clock_init();
 603        calibrate_delay();
 604        pidmap_init();
 605        anon_vma_init();
 606#ifdef CONFIG_X86
 607        if (efi_enabled(EFI_RUNTIME_SERVICES))
 608                efi_enter_virtual_mode();
 609#endif
 610        thread_info_cache_init();
 611        cred_init();
 612        fork_init(totalram_pages);
 613        proc_caches_init();
 614        buffer_init();
 615        key_init();
 616        security_init();
 617        dbg_late_init();
 618        vfs_caches_init(totalram_pages);
 619        signals_init();
 620        /* rootfs populating might need page-writeback */
 621        page_writeback_init();
 622#ifdef CONFIG_PROC_FS
 623        proc_root_init();
 624#endif
 625        cgroup_init();
 626        cpuset_init();
 627        taskstats_init_early();
 628        delayacct_init();
 629
 630        check_bugs();
 631
 632        acpi_early_init(); /* before LAPIC and SMP init */
 633        sfi_init_late();
 634
 635        if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 636                efi_late_init();
 637                efi_free_boot_services();
 638        }
 639
 640        ftrace_init();
 641
 642        /* Do the rest non-__init'ed, we're now alive */
 643        rest_init();
 644}
 645
 646/* Call all constructor functions linked into the kernel. */
 647static void __init do_ctors(void)
 648{
 649#ifdef CONFIG_CONSTRUCTORS
 650        ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 651
 652        for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 653                (*fn)();
 654#endif
 655}
 656
 657bool initcall_debug;
 658core_param(initcall_debug, initcall_debug, bool, 0644);
 659
 660static char msgbuf[64];
 661
 662static int __init_or_module do_one_initcall_debug(initcall_t fn)
 663{
 664        ktime_t calltime, delta, rettime;
 665        unsigned long long duration;
 666        int ret;
 667
 668        printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 669        calltime = ktime_get();
 670        ret = fn();
 671        rettime = ktime_get();
 672        delta = ktime_sub(rettime, calltime);
 673        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 674        printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 675                ret, duration);
 676
 677        return ret;
 678}
 679
 680int __init_or_module do_one_initcall(initcall_t fn)
 681{
 682        int count = preempt_count();
 683        int ret;
 684
 685        if (initcall_debug)
 686                ret = do_one_initcall_debug(fn);
 687        else
 688                ret = fn();
 689
 690        msgbuf[0] = 0;
 691
 692        if (ret && ret != -ENODEV && initcall_debug)
 693                sprintf(msgbuf, "error code %d ", ret);
 694
 695        if (preempt_count() != count) {
 696                strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 697                preempt_count() = count;
 698        }
 699        if (irqs_disabled()) {
 700                strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 701                local_irq_enable();
 702        }
 703        if (msgbuf[0]) {
 704                printk("initcall %pF returned with %s\n", fn, msgbuf);
 705        }
 706
 707        return ret;
 708}
 709
 710
 711extern initcall_t __initcall_start[];
 712extern initcall_t __initcall0_start[];
 713extern initcall_t __initcall1_start[];
 714extern initcall_t __initcall2_start[];
 715extern initcall_t __initcall3_start[];
 716extern initcall_t __initcall4_start[];
 717extern initcall_t __initcall5_start[];
 718extern initcall_t __initcall6_start[];
 719extern initcall_t __initcall7_start[];
 720extern initcall_t __initcall_end[];
 721
 722static initcall_t *initcall_levels[] __initdata = {
 723        __initcall0_start,
 724        __initcall1_start,
 725        __initcall2_start,
 726        __initcall3_start,
 727        __initcall4_start,
 728        __initcall5_start,
 729        __initcall6_start,
 730        __initcall7_start,
 731        __initcall_end,
 732};
 733
 734/* Keep these in sync with initcalls in include/linux/init.h */
 735static char *initcall_level_names[] __initdata = {
 736        "early",
 737        "core",
 738        "postcore",
 739        "arch",
 740        "subsys",
 741        "fs",
 742        "device",
 743        "late",
 744};
 745
 746static void __init do_initcall_level(int level)
 747{
 748        extern const struct kernel_param __start___param[], __stop___param[];
 749        initcall_t *fn;
 750
 751        strcpy(static_command_line, saved_command_line);
 752        parse_args(initcall_level_names[level],
 753                   static_command_line, __start___param,
 754                   __stop___param - __start___param,
 755                   level, level,
 756                   &repair_env_string);
 757
 758        for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 759                do_one_initcall(*fn);
 760}
 761
 762static void __init do_initcalls(void)
 763{
 764        int level;
 765
 766        for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 767                do_initcall_level(level);
 768}
 769
 770/*
 771 * Ok, the machine is now initialized. None of the devices
 772 * have been touched yet, but the CPU subsystem is up and
 773 * running, and memory and process management works.
 774 *
 775 * Now we can finally start doing some real work..
 776 */
 777static void __init do_basic_setup(void)
 778{
 779        cpuset_init_smp();
 780        usermodehelper_init();
 781        shmem_init();
 782        driver_init();
 783        init_irq_proc();
 784        do_ctors();
 785        usermodehelper_enable();
 786        do_initcalls();
 787}
 788
 789static void __init do_pre_smp_initcalls(void)
 790{
 791        initcall_t *fn;
 792
 793        for (fn = __initcall_start; fn < __initcall0_start; fn++)
 794                do_one_initcall(*fn);
 795}
 796
 797static int run_init_process(const char *init_filename)
 798{
 799        argv_init[0] = init_filename;
 800        return kernel_execve(init_filename, argv_init, envp_init);
 801}
 802
 803static noinline void __init kernel_init_freeable(void);
 804
 805static int __ref kernel_init(void *unused)
 806{
 807        kernel_init_freeable();
 808        /* need to finish all async __init code before freeing the memory */
 809        async_synchronize_full();
 810        free_initmem();
 811        mark_rodata_ro();
 812        system_state = SYSTEM_RUNNING;
 813        numa_default_policy();
 814
 815        current->signal->flags |= SIGNAL_UNKILLABLE;
 816        flush_delayed_fput();
 817
 818        if (ramdisk_execute_command) {
 819                if (!run_init_process(ramdisk_execute_command))
 820                        return 0;
 821                printk(KERN_WARNING "Failed to execute %s\n",
 822                                ramdisk_execute_command);
 823        }
 824
 825        /*
 826         * We try each of these until one succeeds.
 827         *
 828         * The Bourne shell can be used instead of init if we are
 829         * trying to recover a really broken machine.
 830         */
 831        if (execute_command) {
 832                if (!run_init_process(execute_command))
 833                        return 0;
 834                printk(KERN_WARNING "Failed to execute %s.  Attempting "
 835                                        "defaults...\n", execute_command);
 836        }
 837        if (!run_init_process("/sbin/init") ||
 838            !run_init_process("/etc/init") ||
 839            !run_init_process("/bin/init") ||
 840            !run_init_process("/bin/sh"))
 841                return 0;
 842
 843        panic("No init found.  Try passing init= option to kernel. "
 844              "See Linux Documentation/init.txt for guidance.");
 845}
 846
 847static noinline void __init kernel_init_freeable(void)
 848{
 849        /*
 850         * Wait until kthreadd is all set-up.
 851         */
 852        wait_for_completion(&kthreadd_done);
 853
 854        /* Now the scheduler is fully set up and can do blocking allocations */
 855        gfp_allowed_mask = __GFP_BITS_MASK;
 856
 857        /*
 858         * init can allocate pages on any node
 859         */
 860        set_mems_allowed(node_states[N_HIGH_MEMORY]);
 861        /*
 862         * init can run on any cpu.
 863         */
 864        set_cpus_allowed_ptr(current, cpu_all_mask);
 865
 866        cad_pid = task_pid(current);
 867
 868        smp_prepare_cpus(setup_max_cpus);
 869
 870        do_pre_smp_initcalls();
 871        lockup_detector_init();
 872
 873        smp_init();
 874        sched_init_smp();
 875
 876        do_basic_setup();
 877
 878        /* Open the /dev/console on the rootfs, this should never fail */
 879        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 880                printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 881
 882        (void) sys_dup(0);
 883        (void) sys_dup(0);
 884        /*
 885         * check if there is an early userspace init.  If yes, let it do all
 886         * the work
 887         */
 888
 889        if (!ramdisk_execute_command)
 890                ramdisk_execute_command = "/init";
 891
 892        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 893                ramdisk_execute_command = NULL;
 894                prepare_namespace();
 895        }
 896
 897        /*
 898         * Ok, we have completed the initial bootup, and
 899         * we're essentially up and running. Get rid of the
 900         * initmem segments and start the user-mode stuff..
 901         */
 902}
 903
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