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/string.h>
  18#include <linux/ctype.h>
  19#include <linux/delay.h>
  20#include <linux/utsname.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/hdreg.h>
  26#include <linux/bootmem.h>
  27#include <linux/tty.h>
  28#include <linux/gfp.h>
  29#include <linux/percpu.h>
  30#include <linux/kmod.h>
  31#include <linux/kernel_stat.h>
  32#include <linux/start_kernel.h>
  33#include <linux/security.h>
  34#include <linux/workqueue.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/unwind.h>
  53#include <linux/buffer_head.h>
  54#include <linux/debug_locks.h>
  55#include <linux/lockdep.h>
  56#include <linux/pid_namespace.h>
  57#include <linux/device.h>
  58#include <linux/kthread.h>
  59#include <linux/sched.h>
  60#include <linux/signal.h>
  61
  62#include <asm/io.h>
  63#include <asm/bugs.h>
  64#include <asm/setup.h>
  65#include <asm/sections.h>
  66#include <asm/cacheflush.h>
  67
  68#ifdef CONFIG_X86_LOCAL_APIC
  69#include <asm/smp.h>
  70#endif
  71
  72/*
  73 * This is one of the first .c files built. Error out early if we have compiler
  74 * trouble.
  75 */
  76
  77#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
  78#warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.
  79#endif
  80
  81static int kernel_init(void *);
  82
  83extern void init_IRQ(void);
  84extern void fork_init(unsigned long);
  85extern void mca_init(void);
  86extern void sbus_init(void);
  87extern void pidhash_init(void);
  88extern void pidmap_init(void);
  89extern void prio_tree_init(void);
  90extern void radix_tree_init(void);
  91extern void free_initmem(void);
  92#ifdef  CONFIG_ACPI
  93extern void acpi_early_init(void);
  94#else
  95static inline void acpi_early_init(void) { }
  96#endif
  97#ifndef CONFIG_DEBUG_RODATA
  98static inline void mark_rodata_ro(void) { }
  99#endif
 100
 101#ifdef CONFIG_TC
 102extern void tc_init(void);
 103#endif
 104
 105enum system_states system_state;
 106EXPORT_SYMBOL(system_state);
 107
 108/*
 109 * Boot command-line arguments
 110 */
 111#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 112#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 113
 114extern void time_init(void);
 115/* Default late time init is NULL. archs can override this later. */
 116void (*late_time_init)(void);
 117extern void softirq_init(void);
 118
 119/* Untouched command line saved by arch-specific code. */
 120char __initdata boot_command_line[COMMAND_LINE_SIZE];
 121/* Untouched saved command line (eg. for /proc) */
 122char *saved_command_line;
 123/* Command line for parameter parsing */
 124static char *static_command_line;
 125
 126static char *execute_command;
 127static char *ramdisk_execute_command;
 128
 129#ifdef CONFIG_SMP
 130/* Setup configured maximum number of CPUs to activate */
 131unsigned int __initdata setup_max_cpus = NR_CPUS;
 132
 133/*
 134 * Setup routine for controlling SMP activation
 135 *
 136 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 137 * activation entirely (the MPS table probe still happens, though).
 138 *
 139 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 140 * greater than 0, limits the maximum number of CPUs activated in
 141 * SMP mode to <NUM>.
 142 */
 143#ifndef CONFIG_X86_IO_APIC
 144static inline void disable_ioapic_setup(void) {};
 145#endif
 146
 147static int __init nosmp(char *str)
 148{
 149        setup_max_cpus = 0;
 150        disable_ioapic_setup();
 151        return 0;
 152}
 153
 154early_param("nosmp", nosmp);
 155
 156static int __init maxcpus(char *str)
 157{
 158        get_option(&str, &setup_max_cpus);
 159        if (setup_max_cpus == 0)
 160                disable_ioapic_setup();
 161
 162        return 0;
 163}
 164
 165early_param("maxcpus", maxcpus);
 166#else
 167#define setup_max_cpus NR_CPUS
 168#endif
 169
 170/*
 171 * If set, this is an indication to the drivers that reset the underlying
 172 * device before going ahead with the initialization otherwise driver might
 173 * rely on the BIOS and skip the reset operation.
 174 *
 175 * This is useful if kernel is booting in an unreliable environment.
 176 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 177 * skipped and devices will be in unknown state.
 178 */
 179unsigned int reset_devices;
 180EXPORT_SYMBOL(reset_devices);
 181
 182static int __init set_reset_devices(char *str)
 183{
 184        reset_devices = 1;
 185        return 1;
 186}
 187
 188__setup("reset_devices", set_reset_devices);
 189
 190static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 191char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 192static const char *panic_later, *panic_param;
 193
 194extern struct obs_kernel_param __setup_start[], __setup_end[];
 195
 196static int __init obsolete_checksetup(char *line)
 197{
 198        struct obs_kernel_param *p;
 199        int had_early_param = 0;
 200
 201        p = __setup_start;
 202        do {
 203                int n = strlen(p->str);
 204                if (!strncmp(line, p->str, n)) {
 205                        if (p->early) {
 206                                /* Already done in parse_early_param?
 207                                 * (Needs exact match on param part).
 208                                 * Keep iterating, as we can have early
 209                                 * params and __setups of same names 8( */
 210                                if (line[n] == '\0' || line[n] == '=')
 211                                        had_early_param = 1;
 212                        } else if (!p->setup_func) {
 213                                printk(KERN_WARNING "Parameter %s is obsolete,"
 214                                       " ignored\n", p->str);
 215                                return 1;
 216                        } else if (p->setup_func(line + n))
 217                                return 1;
 218                }
 219                p++;
 220        } while (p < __setup_end);
 221
 222        return had_early_param;
 223}
 224
 225/*
 226 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 227 * still work even if initially too large, it will just take slightly longer
 228 */
 229unsigned long loops_per_jiffy = (1<<12);
 230
 231EXPORT_SYMBOL(loops_per_jiffy);
 232
 233static int __init debug_kernel(char *str)
 234{
 235        console_loglevel = 10;
 236        return 0;
 237}
 238
 239static int __init quiet_kernel(char *str)
 240{
 241        console_loglevel = 4;
 242        return 0;
 243}
 244
 245early_param("debug", debug_kernel);
 246early_param("quiet", quiet_kernel);
 247
 248static int __init loglevel(char *str)
 249{
 250        get_option(&str, &console_loglevel);
 251        return 0;
 252}
 253
 254early_param("loglevel", loglevel);
 255
 256/*
 257 * Unknown boot options get handed to init, unless they look like
 258 * failed parameters
 259 */
 260static int __init unknown_bootoption(char *param, char *val)
 261{
 262        /* Change NUL term back to "=", to make "param" the whole string. */
 263        if (val) {
 264                /* param=val or param="val"? */
 265                if (val == param+strlen(param)+1)
 266                        val[-1] = '=';
 267                else if (val == param+strlen(param)+2) {
 268                        val[-2] = '=';
 269                        memmove(val-1, val, strlen(val)+1);
 270                        val--;
 271                } else
 272                        BUG();
 273        }
 274
 275        /* Handle obsolete-style parameters */
 276        if (obsolete_checksetup(param))
 277                return 0;
 278
 279        /*
 280         * Preemptive maintenance for "why didn't my misspelled command
 281         * line work?"
 282         */
 283        if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 284                printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 285                return 0;
 286        }
 287
 288        if (panic_later)
 289                return 0;
 290
 291        if (val) {
 292                /* Environment option */
 293                unsigned int i;
 294                for (i = 0; envp_init[i]; i++) {
 295                        if (i == MAX_INIT_ENVS) {
 296                                panic_later = "Too many boot env vars at `%s'";
 297                                panic_param = param;
 298                        }
 299                        if (!strncmp(param, envp_init[i], val - param))
 300                                break;
 301                }
 302                envp_init[i] = param;
 303        } else {
 304                /* Command line option */
 305                unsigned int i;
 306                for (i = 0; argv_init[i]; i++) {
 307                        if (i == MAX_INIT_ARGS) {
 308                                panic_later = "Too many boot init vars at `%s'";
 309                                panic_param = param;
 310                        }
 311                }
 312                argv_init[i] = param;
 313        }
 314        return 0;
 315}
 316
 317#ifdef CONFIG_DEBUG_PAGEALLOC
 318int __read_mostly debug_pagealloc_enabled = 0;
 319#endif
 320
 321static int __init init_setup(char *str)
 322{
 323        unsigned int i;
 324
 325        execute_command = str;
 326        /*
 327         * In case LILO is going to boot us with default command line,
 328         * it prepends "auto" before the whole cmdline which makes
 329         * the shell think it should execute a script with such name.
 330         * So we ignore all arguments entered _before_ init=... [MJ]
 331         */
 332        for (i = 1; i < MAX_INIT_ARGS; i++)
 333                argv_init[i] = NULL;
 334        return 1;
 335}
 336__setup("init=", init_setup);
 337
 338static int __init rdinit_setup(char *str)
 339{
 340        unsigned int i;
 341
 342        ramdisk_execute_command = str;
 343        /* See "auto" comment in init_setup */
 344        for (i = 1; i < MAX_INIT_ARGS; i++)
 345                argv_init[i] = NULL;
 346        return 1;
 347}
 348__setup("rdinit=", rdinit_setup);
 349
 350#ifndef CONFIG_SMP
 351
 352#ifdef CONFIG_X86_LOCAL_APIC
 353static void __init smp_init(void)
 354{
 355        APIC_init_uniprocessor();
 356}
 357#else
 358#define smp_init()      do { } while (0)
 359#endif
 360
 361static inline void setup_per_cpu_areas(void) { }
 362static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 363
 364#else
 365
 366#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
 367unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 368
 369EXPORT_SYMBOL(__per_cpu_offset);
 370
 371static void __init setup_per_cpu_areas(void)
 372{
 373        unsigned long size, i;
 374        char *ptr;
 375        unsigned long nr_possible_cpus = num_possible_cpus();
 376
 377        /* Copy section for each CPU (we discard the original) */
 378        size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
 379        ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 380
 381        for_each_possible_cpu(i) {
 382                __per_cpu_offset[i] = ptr - __per_cpu_start;
 383                memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 384                ptr += size;
 385        }
 386}
 387#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
 388
 389/* Called by boot processor to activate the rest. */
 390static void __init smp_init(void)
 391{
 392        unsigned int cpu;
 393
 394        /* FIXME: This should be done in userspace --RR */
 395        for_each_present_cpu(cpu) {
 396                if (num_online_cpus() >= setup_max_cpus)
 397                        break;
 398                if (!cpu_online(cpu))
 399                        cpu_up(cpu);
 400        }
 401
 402        /* Any cleanup work */
 403        printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 404        smp_cpus_done(setup_max_cpus);
 405}
 406
 407#endif
 408
 409/*
 410 * We need to store the untouched command line for future reference.
 411 * We also need to store the touched command line since the parameter
 412 * parsing is performed in place, and we should allow a component to
 413 * store reference of name/value for future reference.
 414 */
 415static void __init setup_command_line(char *command_line)
 416{
 417        saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 418        static_command_line = alloc_bootmem(strlen (command_line)+1);
 419        strcpy (saved_command_line, boot_command_line);
 420        strcpy (static_command_line, command_line);
 421}
 422
 423/*
 424 * We need to finalize in a non-__init function or else race conditions
 425 * between the root thread and the init thread may cause start_kernel to
 426 * be reaped by free_initmem before the root thread has proceeded to
 427 * cpu_idle.
 428 *
 429 * gcc-3.4 accidentally inlines this function, so use noinline.
 430 */
 431
 432static void noinline __init_refok rest_init(void)
 433        __releases(kernel_lock)
 434{
 435        int pid;
 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        kthreadd_task = find_task_by_pid(pid);
 441        unlock_kernel();
 442
 443        /*
 444         * The boot idle thread must execute schedule()
 445         * at least once to get things moving:
 446         */
 447        init_idle_bootup_task(current);
 448        preempt_enable_no_resched();
 449        schedule();
 450        preempt_disable();
 451
 452        /* Call into cpu_idle with preempt disabled */
 453        cpu_idle();
 454}
 455
 456/* Check for early params. */
 457static int __init do_early_param(char *param, char *val)
 458{
 459        struct obs_kernel_param *p;
 460
 461        for (p = __setup_start; p < __setup_end; p++) {
 462                if ((p->early && strcmp(param, p->str) == 0) ||
 463                    (strcmp(param, "console") == 0 &&
 464                     strcmp(p->str, "earlycon") == 0)
 465                ) {
 466                        if (p->setup_func(val) != 0)
 467                                printk(KERN_WARNING
 468                                       "Malformed early option '%s'\n", param);
 469                }
 470        }
 471        /* We accept everything at this stage. */
 472        return 0;
 473}
 474
 475/* Arch code calls this early on, or if not, just before other parsing. */
 476void __init parse_early_param(void)
 477{
 478        static __initdata int done = 0;
 479        static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 480
 481        if (done)
 482                return;
 483
 484        /* All fall through to do_early_param. */
 485        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 486        parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 487        done = 1;
 488}
 489
 490/*
 491 *      Activate the first processor.
 492 */
 493
 494static void __init boot_cpu_init(void)
 495{
 496        int cpu = smp_processor_id();
 497        /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 498        cpu_set(cpu, cpu_online_map);
 499        cpu_set(cpu, cpu_present_map);
 500        cpu_set(cpu, cpu_possible_map);
 501}
 502
 503void __init __attribute__((weak)) smp_setup_processor_id(void)
 504{
 505}
 506
 507asmlinkage void __init start_kernel(void)
 508{
 509        char * command_line;
 510        extern struct kernel_param __start___param[], __stop___param[];
 511
 512        smp_setup_processor_id();
 513
 514        /*
 515         * Need to run as early as possible, to initialize the
 516         * lockdep hash:
 517         */
 518        unwind_init();
 519        lockdep_init();
 520        cgroup_init_early();
 521
 522        local_irq_disable();
 523        early_boot_irqs_off();
 524        early_init_irq_lock_class();
 525
 526/*
 527 * Interrupts are still disabled. Do necessary setups, then
 528 * enable them
 529 */
 530        lock_kernel();
 531        tick_init();
 532        boot_cpu_init();
 533        page_address_init();
 534        printk(KERN_NOTICE);
 535        printk(linux_banner);
 536        setup_arch(&command_line);
 537        setup_command_line(command_line);
 538        unwind_setup();
 539        setup_per_cpu_areas();
 540        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 541
 542        /*
 543         * Set up the scheduler prior starting any interrupts (such as the
 544         * timer interrupt). Full topology setup happens at smp_init()
 545         * time - but meanwhile we still have a functioning scheduler.
 546         */
 547        sched_init();
 548        /*
 549         * Disable preemption - early bootup scheduling is extremely
 550         * fragile until we cpu_idle() for the first time.
 551         */
 552        preempt_disable();
 553        build_all_zonelists();
 554        page_alloc_init();
 555        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 556        parse_early_param();
 557        parse_args("Booting kernel", static_command_line, __start___param,
 558                   __stop___param - __start___param,
 559                   &unknown_bootoption);
 560        if (!irqs_disabled()) {
 561                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 562                                "enabled *very* early, fixing it\n");
 563                local_irq_disable();
 564        }
 565        sort_main_extable();
 566        trap_init();
 567        rcu_init();
 568        init_IRQ();
 569        pidhash_init();
 570        init_timers();
 571        hrtimers_init();
 572        softirq_init();
 573        timekeeping_init();
 574        time_init();
 575        profile_init();
 576        if (!irqs_disabled())
 577                printk("start_kernel(): bug: interrupts were enabled early\n");
 578        early_boot_irqs_on();
 579        local_irq_enable();
 580
 581        /*
 582         * HACK ALERT! This is early. We're enabling the console before
 583         * we've done PCI setups etc, and console_init() must be aware of
 584         * this. But we do want output early, in case something goes wrong.
 585         */
 586        console_init();
 587        if (panic_later)
 588                panic(panic_later, panic_param);
 589
 590        lockdep_info();
 591
 592        /*
 593         * Need to run this when irqs are enabled, because it wants
 594         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 595         * too:
 596         */
 597        locking_selftest();
 598
 599#ifdef CONFIG_BLK_DEV_INITRD
 600        if (initrd_start && !initrd_below_start_ok &&
 601                        initrd_start < min_low_pfn << PAGE_SHIFT) {
 602                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 603                    "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 604                initrd_start = 0;
 605        }
 606#endif
 607        vfs_caches_init_early();
 608        cpuset_init_early();
 609        mem_init();
 610        enable_debug_pagealloc();
 611        cpu_hotplug_init();
 612        kmem_cache_init();
 613        setup_per_cpu_pageset();
 614        numa_policy_init();
 615        if (late_time_init)
 616                late_time_init();
 617        calibrate_delay();
 618        pidmap_init();
 619        pgtable_cache_init();
 620        prio_tree_init();
 621        anon_vma_init();
 622#ifdef CONFIG_X86
 623        if (efi_enabled)
 624                efi_enter_virtual_mode();
 625#endif
 626        fork_init(num_physpages);
 627        proc_caches_init();
 628        buffer_init();
 629        unnamed_dev_init();
 630        key_init();
 631        security_init();
 632        vfs_caches_init(num_physpages);
 633        radix_tree_init();
 634        signals_init();
 635        /* rootfs populating might need page-writeback */
 636        page_writeback_init();
 637#ifdef CONFIG_PROC_FS
 638        proc_root_init();
 639#endif
 640        cgroup_init();
 641        cpuset_init();
 642        taskstats_init_early();
 643        delayacct_init();
 644
 645        check_bugs();
 646
 647        acpi_early_init(); /* before LAPIC and SMP init */
 648
 649        /* Do the rest non-__init'ed, we're now alive */
 650        rest_init();
 651}
 652
 653static int __initdata initcall_debug;
 654
 655static int __init initcall_debug_setup(char *str)
 656{
 657        initcall_debug = 1;
 658        return 1;
 659}
 660__setup("initcall_debug", initcall_debug_setup);
 661
 662extern initcall_t __initcall_start[], __initcall_end[];
 663
 664static void __init do_initcalls(void)
 665{
 666        initcall_t *call;
 667        int count = preempt_count();
 668
 669        for (call = __initcall_start; call < __initcall_end; call++) {
 670                ktime_t t0, t1, delta;
 671                char *msg = NULL;
 672                char msgbuf[40];
 673                int result;
 674
 675                if (initcall_debug) {
 676                        printk("Calling initcall 0x%p", *call);
 677                        print_fn_descriptor_symbol(": %s()",
 678                                        (unsigned long) *call);
 679                        printk("\n");
 680                        t0 = ktime_get();
 681                }
 682
 683                result = (*call)();
 684
 685                if (initcall_debug) {
 686                        t1 = ktime_get();
 687                        delta = ktime_sub(t1, t0);
 688
 689                        printk("initcall 0x%p", *call);
 690                        print_fn_descriptor_symbol(": %s()",
 691                                        (unsigned long) *call);
 692                        printk(" returned %d.\n", result);
 693
 694                        printk("initcall 0x%p ran for %Ld msecs: ",
 695                                *call, (unsigned long long)delta.tv64 >> 20);
 696                        print_fn_descriptor_symbol("%s()\n",
 697                                (unsigned long) *call);
 698                }
 699
 700                if (result && result != -ENODEV && initcall_debug) {
 701                        sprintf(msgbuf, "error code %d", result);
 702                        msg = msgbuf;
 703                }
 704                if (preempt_count() != count) {
 705                        msg = "preemption imbalance";
 706                        preempt_count() = count;
 707                }
 708                if (irqs_disabled()) {
 709                        msg = "disabled interrupts";
 710                        local_irq_enable();
 711                }
 712                if (msg) {
 713                        printk(KERN_WARNING "initcall at 0x%p", *call);
 714                        print_fn_descriptor_symbol(": %s()",
 715                                        (unsigned long) *call);
 716                        printk(": returned with %s\n", msg);
 717                }
 718        }
 719
 720        /* Make sure there is no pending stuff from the initcall sequence */
 721        flush_scheduled_work();
 722}
 723
 724/*
 725 * Ok, the machine is now initialized. None of the devices
 726 * have been touched yet, but the CPU subsystem is up and
 727 * running, and memory and process management works.
 728 *
 729 * Now we can finally start doing some real work..
 730 */
 731static void __init do_basic_setup(void)
 732{
 733        /* drivers will send hotplug events */
 734        init_workqueues();
 735        usermodehelper_init();
 736        driver_init();
 737        init_irq_proc();
 738        do_initcalls();
 739}
 740
 741static int __initdata nosoftlockup;
 742
 743static int __init nosoftlockup_setup(char *str)
 744{
 745        nosoftlockup = 1;
 746        return 1;
 747}
 748__setup("nosoftlockup", nosoftlockup_setup);
 749
 750static void __init do_pre_smp_initcalls(void)
 751{
 752        extern int spawn_ksoftirqd(void);
 753
 754        migration_init();
 755        spawn_ksoftirqd();
 756        if (!nosoftlockup)
 757                spawn_softlockup_task();
 758}
 759
 760static void run_init_process(char *init_filename)
 761{
 762        argv_init[0] = init_filename;
 763        kernel_execve(init_filename, argv_init, envp_init);
 764}
 765
 766/* This is a non __init function. Force it to be noinline otherwise gcc
 767 * makes it inline to init() and it becomes part of init.text section
 768 */
 769static int noinline init_post(void)
 770{
 771        free_initmem();
 772        unlock_kernel();
 773        mark_rodata_ro();
 774        system_state = SYSTEM_RUNNING;
 775        numa_default_policy();
 776
 777        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 778                printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 779
 780        (void) sys_dup(0);
 781        (void) sys_dup(0);
 782
 783        if (ramdisk_execute_command) {
 784                run_init_process(ramdisk_execute_command);
 785                printk(KERN_WARNING "Failed to execute %s\n",
 786                                ramdisk_execute_command);
 787        }
 788
 789        /*
 790         * We try each of these until one succeeds.
 791         *
 792         * The Bourne shell can be used instead of init if we are
 793         * trying to recover a really broken machine.
 794         */
 795        if (execute_command) {
 796                run_init_process(execute_command);
 797                printk(KERN_WARNING "Failed to execute %s.  Attempting "
 798                                        "defaults...\n", execute_command);
 799        }
 800        run_init_process("/sbin/init");
 801        run_init_process("/etc/init");
 802        run_init_process("/bin/init");
 803        run_init_process("/bin/sh");
 804
 805        panic("No init found.  Try passing init= option to kernel.");
 806}
 807
 808static int __init kernel_init(void * unused)
 809{
 810        lock_kernel();
 811        /*
 812         * init can run on any cpu.
 813         */
 814        set_cpus_allowed(current, CPU_MASK_ALL);
 815        /*
 816         * Tell the world that we're going to be the grim
 817         * reaper of innocent orphaned children.
 818         *
 819         * We don't want people to have to make incorrect
 820         * assumptions about where in the task array this
 821         * can be found.
 822         */
 823        init_pid_ns.child_reaper = current;
 824
 825        cad_pid = task_pid(current);
 826
 827        smp_prepare_cpus(setup_max_cpus);
 828
 829        do_pre_smp_initcalls();
 830
 831        smp_init();
 832        sched_init_smp();
 833
 834        cpuset_init_smp();
 835
 836        do_basic_setup();
 837
 838        /*
 839         * check if there is an early userspace init.  If yes, let it do all
 840         * the work
 841         */
 842
 843        if (!ramdisk_execute_command)
 844                ramdisk_execute_command = "/init";
 845
 846        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 847                ramdisk_execute_command = NULL;
 848                prepare_namespace();
 849        }
 850
 851        /*
 852         * Ok, we have completed the initial bootup, and
 853         * we're essentially up and running. Get rid of the
 854         * initmem segments and start the user-mode stuff..
 855         */
 856        init_post();
 857        return 0;
 858}
 859
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