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/smp_lock.h>
  24#include <linux/initrd.h>
  25#include <linux/bootmem.h>
  26#include <linux/acpi.h>
  27#include <linux/tty.h>
  28#include <linux/percpu.h>
  29#include <linux/kmod.h>
  30#include <linux/vmalloc.h>
  31#include <linux/kernel_stat.h>
  32#include <linux/start_kernel.h>
  33#include <linux/security.h>
  34#include <linux/smp.h>
  35#include <linux/profile.h>
  36#include <linux/rcupdate.h>
  37#include <linux/moduleparam.h>
  38#include <linux/kallsyms.h>
  39#include <linux/writeback.h>
  40#include <linux/cpu.h>
  41#include <linux/cpuset.h>
  42#include <linux/cgroup.h>
  43#include <linux/efi.h>
  44#include <linux/tick.h>
  45#include <linux/interrupt.h>
  46#include <linux/taskstats_kern.h>
  47#include <linux/delayacct.h>
  48#include <linux/unistd.h>
  49#include <linux/rmap.h>
  50#include <linux/mempolicy.h>
  51#include <linux/key.h>
  52#include <linux/buffer_head.h>
  53#include <linux/page_cgroup.h>
  54#include <linux/debug_locks.h>
  55#include <linux/debugobjects.h>
  56#include <linux/lockdep.h>
  57#include <linux/kmemleak.h>
  58#include <linux/pid_namespace.h>
  59#include <linux/device.h>
  60#include <linux/kthread.h>
  61#include <linux/sched.h>
  62#include <linux/signal.h>
  63#include <linux/idr.h>
  64#include <linux/kgdb.h>
  65#include <linux/ftrace.h>
  66#include <linux/async.h>
  67#include <linux/kmemcheck.h>
  68#include <linux/sfi.h>
  69#include <linux/shmem_fs.h>
  70#include <linux/slab.h>
  71
  72#include <asm/io.h>
  73#include <asm/bugs.h>
  74#include <asm/setup.h>
  75#include <asm/sections.h>
  76#include <asm/cacheflush.h>
  77
  78#ifdef CONFIG_X86_LOCAL_APIC
  79#include <asm/smp.h>
  80#endif
  81
  82static int kernel_init(void *);
  83
  84extern void init_IRQ(void);
  85extern void fork_init(unsigned long);
  86extern void mca_init(void);
  87extern void sbus_init(void);
  88extern void prio_tree_init(void);
  89extern void radix_tree_init(void);
  90extern void free_initmem(void);
  91#ifndef CONFIG_DEBUG_RODATA
  92static inline void mark_rodata_ro(void) { }
  93#endif
  94
  95#ifdef CONFIG_TC
  96extern void tc_init(void);
  97#endif
  98
  99enum system_states system_state __read_mostly;
 100EXPORT_SYMBOL(system_state);
 101
 102/*
 103 * Boot command-line arguments
 104 */
 105#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 106#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 107
 108extern void time_init(void);
 109/* Default late time init is NULL. archs can override this later. */
 110void (*__initdata late_time_init)(void);
 111extern void softirq_init(void);
 112
 113/* Untouched command line saved by arch-specific code. */
 114char __initdata boot_command_line[COMMAND_LINE_SIZE];
 115/* Untouched saved command line (eg. for /proc) */
 116char *saved_command_line;
 117/* Command line for parameter parsing */
 118static char *static_command_line;
 119
 120static char *execute_command;
 121static char *ramdisk_execute_command;
 122
 123#ifdef CONFIG_SMP
 124/* Setup configured maximum number of CPUs to activate */
 125unsigned int setup_max_cpus = NR_CPUS;
 126EXPORT_SYMBOL(setup_max_cpus);
 127
 128
 129/*
 130 * Setup routine for controlling SMP activation
 131 *
 132 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 133 * activation entirely (the MPS table probe still happens, though).
 134 *
 135 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 136 * greater than 0, limits the maximum number of CPUs activated in
 137 * SMP mode to <NUM>.
 138 */
 139
 140void __weak arch_disable_smp_support(void) { }
 141
 142static int __init nosmp(char *str)
 143{
 144        setup_max_cpus = 0;
 145        arch_disable_smp_support();
 146
 147        return 0;
 148}
 149
 150early_param("nosmp", nosmp);
 151
 152/* this is hard limit */
 153static int __init nrcpus(char *str)
 154{
 155        int nr_cpus;
 156
 157        get_option(&str, &nr_cpus);
 158        if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
 159                nr_cpu_ids = nr_cpus;
 160
 161        return 0;
 162}
 163
 164early_param("nr_cpus", nrcpus);
 165
 166static int __init maxcpus(char *str)
 167{
 168        get_option(&str, &setup_max_cpus);
 169        if (setup_max_cpus == 0)
 170                arch_disable_smp_support();
 171
 172        return 0;
 173}
 174
 175early_param("maxcpus", maxcpus);
 176#else
 177static const unsigned int setup_max_cpus = NR_CPUS;
 178#endif
 179
 180/*
 181 * If set, this is an indication to the drivers that reset the underlying
 182 * device before going ahead with the initialization otherwise driver might
 183 * rely on the BIOS and skip the reset operation.
 184 *
 185 * This is useful if kernel is booting in an unreliable environment.
 186 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 187 * skipped and devices will be in unknown state.
 188 */
 189unsigned int reset_devices;
 190EXPORT_SYMBOL(reset_devices);
 191
 192static int __init set_reset_devices(char *str)
 193{
 194        reset_devices = 1;
 195        return 1;
 196}
 197
 198__setup("reset_devices", set_reset_devices);
 199
 200static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 201const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 202static const char *panic_later, *panic_param;
 203
 204extern const struct obs_kernel_param __setup_start[], __setup_end[];
 205
 206static int __init obsolete_checksetup(char *line)
 207{
 208        const struct obs_kernel_param *p;
 209        int had_early_param = 0;
 210
 211        p = __setup_start;
 212        do {
 213                int n = strlen(p->str);
 214                if (!strncmp(line, p->str, n)) {
 215                        if (p->early) {
 216                                /* Already done in parse_early_param?
 217                                 * (Needs exact match on param part).
 218                                 * Keep iterating, as we can have early
 219                                 * params and __setups of same names 8( */
 220                                if (line[n] == '\0' || line[n] == '=')
 221                                        had_early_param = 1;
 222                        } else if (!p->setup_func) {
 223                                printk(KERN_WARNING "Parameter %s is obsolete,"
 224                                       " ignored\n", p->str);
 225                                return 1;
 226                        } else if (p->setup_func(line + n))
 227                                return 1;
 228                }
 229                p++;
 230        } while (p < __setup_end);
 231
 232        return had_early_param;
 233}
 234
 235/*
 236 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 237 * still work even if initially too large, it will just take slightly longer
 238 */
 239unsigned long loops_per_jiffy = (1<<12);
 240
 241EXPORT_SYMBOL(loops_per_jiffy);
 242
 243static int __init debug_kernel(char *str)
 244{
 245        console_loglevel = 10;
 246        return 0;
 247}
 248
 249static int __init quiet_kernel(char *str)
 250{
 251        console_loglevel = 4;
 252        return 0;
 253}
 254
 255early_param("debug", debug_kernel);
 256early_param("quiet", quiet_kernel);
 257
 258static int __init loglevel(char *str)
 259{
 260        get_option(&str, &console_loglevel);
 261        return 0;
 262}
 263
 264early_param("loglevel", loglevel);
 265
 266/*
 267 * Unknown boot options get handed to init, unless they look like
 268 * unused parameters (modprobe will find them in /proc/cmdline).
 269 */
 270static int __init unknown_bootoption(char *param, char *val)
 271{
 272        /* Change NUL term back to "=", to make "param" the whole string. */
 273        if (val) {
 274                /* param=val or param="val"? */
 275                if (val == param+strlen(param)+1)
 276                        val[-1] = '=';
 277                else if (val == param+strlen(param)+2) {
 278                        val[-2] = '=';
 279                        memmove(val-1, val, strlen(val)+1);
 280                        val--;
 281                } else
 282                        BUG();
 283        }
 284
 285        /* Handle obsolete-style parameters */
 286        if (obsolete_checksetup(param))
 287                return 0;
 288
 289        /* Unused module parameter. */
 290        if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 291                return 0;
 292
 293        if (panic_later)
 294                return 0;
 295
 296        if (val) {
 297                /* Environment option */
 298                unsigned int i;
 299                for (i = 0; envp_init[i]; i++) {
 300                        if (i == MAX_INIT_ENVS) {
 301                                panic_later = "Too many boot env vars at `%s'";
 302                                panic_param = param;
 303                        }
 304                        if (!strncmp(param, envp_init[i], val - param))
 305                                break;
 306                }
 307                envp_init[i] = param;
 308        } else {
 309                /* Command line option */
 310                unsigned int i;
 311                for (i = 0; argv_init[i]; i++) {
 312                        if (i == MAX_INIT_ARGS) {
 313                                panic_later = "Too many boot init vars at `%s'";
 314                                panic_param = param;
 315                        }
 316                }
 317                argv_init[i] = param;
 318        }
 319        return 0;
 320}
 321
 322#ifdef CONFIG_DEBUG_PAGEALLOC
 323int __read_mostly debug_pagealloc_enabled = 0;
 324#endif
 325
 326static int __init init_setup(char *str)
 327{
 328        unsigned int i;
 329
 330        execute_command = str;
 331        /*
 332         * In case LILO is going to boot us with default command line,
 333         * it prepends "auto" before the whole cmdline which makes
 334         * the shell think it should execute a script with such name.
 335         * So we ignore all arguments entered _before_ init=... [MJ]
 336         */
 337        for (i = 1; i < MAX_INIT_ARGS; i++)
 338                argv_init[i] = NULL;
 339        return 1;
 340}
 341__setup("init=", init_setup);
 342
 343static int __init rdinit_setup(char *str)
 344{
 345        unsigned int i;
 346
 347        ramdisk_execute_command = str;
 348        /* See "auto" comment in init_setup */
 349        for (i = 1; i < MAX_INIT_ARGS; i++)
 350                argv_init[i] = NULL;
 351        return 1;
 352}
 353__setup("rdinit=", rdinit_setup);
 354
 355#ifndef CONFIG_SMP
 356
 357#ifdef CONFIG_X86_LOCAL_APIC
 358static void __init smp_init(void)
 359{
 360        APIC_init_uniprocessor();
 361}
 362#else
 363#define smp_init()      do { } while (0)
 364#endif
 365
 366static inline void setup_nr_cpu_ids(void) { }
 367static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 368
 369#else
 370
 371/* Setup number of possible processor ids */
 372int nr_cpu_ids __read_mostly = NR_CPUS;
 373EXPORT_SYMBOL(nr_cpu_ids);
 374
 375/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 376static void __init setup_nr_cpu_ids(void)
 377{
 378        nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 379}
 380
 381/* Called by boot processor to activate the rest. */
 382static void __init smp_init(void)
 383{
 384        unsigned int cpu;
 385
 386        /* FIXME: This should be done in userspace --RR */
 387        for_each_present_cpu(cpu) {
 388                if (num_online_cpus() >= setup_max_cpus)
 389                        break;
 390                if (!cpu_online(cpu))
 391                        cpu_up(cpu);
 392        }
 393
 394        /* Any cleanup work */
 395        printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 396        smp_cpus_done(setup_max_cpus);
 397}
 398
 399#endif
 400
 401/*
 402 * We need to store the untouched command line for future reference.
 403 * We also need to store the touched command line since the parameter
 404 * parsing is performed in place, and we should allow a component to
 405 * store reference of name/value for future reference.
 406 */
 407static void __init setup_command_line(char *command_line)
 408{
 409        saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 410        static_command_line = alloc_bootmem(strlen (command_line)+1);
 411        strcpy (saved_command_line, boot_command_line);
 412        strcpy (static_command_line, command_line);
 413}
 414
 415/*
 416 * We need to finalize in a non-__init function or else race conditions
 417 * between the root thread and the init thread may cause start_kernel to
 418 * be reaped by free_initmem before the root thread has proceeded to
 419 * cpu_idle.
 420 *
 421 * gcc-3.4 accidentally inlines this function, so use noinline.
 422 */
 423
 424static __initdata DECLARE_COMPLETION(kthreadd_done);
 425
 426static noinline void __init_refok rest_init(void)
 427        __releases(kernel_lock)
 428{
 429        int pid;
 430
 431        rcu_scheduler_starting();
 432        /*
 433         * We need to spawn init first so that it obtains pid 1, however
 434         * the init task will end up wanting to create kthreads, which, if
 435         * we schedule it before we create kthreadd, will OOPS.
 436         */
 437        kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 438        numa_default_policy();
 439        pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 440        rcu_read_lock();
 441        kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 442        rcu_read_unlock();
 443        complete(&kthreadd_done);
 444
 445        /*
 446         * The boot idle thread must execute schedule()
 447         * at least once to get things moving:
 448         */
 449        init_idle_bootup_task(current);
 450        preempt_enable_no_resched();
 451        schedule();
 452        preempt_disable();
 453
 454        /* Call into cpu_idle with preempt disabled */
 455        cpu_idle();
 456}
 457
 458/* Check for early params. */
 459static int __init do_early_param(char *param, char *val)
 460{
 461        const struct obs_kernel_param *p;
 462
 463        for (p = __setup_start; p < __setup_end; p++) {
 464                if ((p->early && strcmp(param, p->str) == 0) ||
 465                    (strcmp(param, "console") == 0 &&
 466                     strcmp(p->str, "earlycon") == 0)
 467                ) {
 468                        if (p->setup_func(val) != 0)
 469                                printk(KERN_WARNING
 470                                       "Malformed early option '%s'\n", param);
 471                }
 472        }
 473        /* We accept everything at this stage. */
 474        return 0;
 475}
 476
 477void __init parse_early_options(char *cmdline)
 478{
 479        parse_args("early options", cmdline, NULL, 0, do_early_param);
 480}
 481
 482/* Arch code calls this early on, or if not, just before other parsing. */
 483void __init parse_early_param(void)
 484{
 485        static __initdata int done = 0;
 486        static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 487
 488        if (done)
 489                return;
 490
 491        /* All fall through to do_early_param. */
 492        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 493        parse_early_options(tmp_cmdline);
 494        done = 1;
 495}
 496
 497/*
 498 *      Activate the first processor.
 499 */
 500
 501static void __init boot_cpu_init(void)
 502{
 503        int cpu = smp_processor_id();
 504        /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 505        set_cpu_online(cpu, true);
 506        set_cpu_active(cpu, true);
 507        set_cpu_present(cpu, true);
 508        set_cpu_possible(cpu, true);
 509}
 510
 511void __init __weak smp_setup_processor_id(void)
 512{
 513}
 514
 515void __init __weak thread_info_cache_init(void)
 516{
 517}
 518
 519/*
 520 * Set up kernel memory allocators
 521 */
 522static void __init mm_init(void)
 523{
 524        /*
 525         * page_cgroup requires countinous pages as memmap
 526         * and it's bigger than MAX_ORDER unless SPARSEMEM.
 527         */
 528        page_cgroup_init_flatmem();
 529        mem_init();
 530        kmem_cache_init();
 531        percpu_init_late();
 532        pgtable_cache_init();
 533        vmalloc_init();
 534}
 535
 536asmlinkage void __init start_kernel(void)
 537{
 538        char * command_line;
 539        extern const struct kernel_param __start___param[], __stop___param[];
 540
 541        smp_setup_processor_id();
 542
 543        /*
 544         * Need to run as early as possible, to initialize the
 545         * lockdep hash:
 546         */
 547        lockdep_init();
 548        debug_objects_early_init();
 549
 550        /*
 551         * Set up the the initial canary ASAP:
 552         */
 553        boot_init_stack_canary();
 554
 555        cgroup_init_early();
 556
 557        local_irq_disable();
 558        early_boot_irqs_off();
 559        early_init_irq_lock_class();
 560
 561/*
 562 * Interrupts are still disabled. Do necessary setups, then
 563 * enable them
 564 */
 565        tick_init();
 566        boot_cpu_init();
 567        page_address_init();
 568        printk(KERN_NOTICE "%s", linux_banner);
 569        setup_arch(&command_line);
 570        mm_init_owner(&init_mm, &init_task);
 571        setup_command_line(command_line);
 572        setup_nr_cpu_ids();
 573        setup_per_cpu_areas();
 574        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 575
 576        build_all_zonelists(NULL);
 577        page_alloc_init();
 578
 579        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 580        parse_early_param();
 581        parse_args("Booting kernel", static_command_line, __start___param,
 582                   __stop___param - __start___param,
 583                   &unknown_bootoption);
 584        /*
 585         * These use large bootmem allocations and must precede
 586         * kmem_cache_init()
 587         */
 588        pidhash_init();
 589        vfs_caches_init_early();
 590        sort_main_extable();
 591        trap_init();
 592        mm_init();
 593        /*
 594         * Set up the scheduler prior starting any interrupts (such as the
 595         * timer interrupt). Full topology setup happens at smp_init()
 596         * time - but meanwhile we still have a functioning scheduler.
 597         */
 598        sched_init();
 599        /*
 600         * Disable preemption - early bootup scheduling is extremely
 601         * fragile until we cpu_idle() for the first time.
 602         */
 603        preempt_disable();
 604        if (!irqs_disabled()) {
 605                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 606                                "enabled *very* early, fixing it\n");
 607                local_irq_disable();
 608        }
 609        rcu_init();
 610        radix_tree_init();
 611        /* init some links before init_ISA_irqs() */
 612        early_irq_init();
 613        init_IRQ();
 614        prio_tree_init();
 615        init_timers();
 616        hrtimers_init();
 617        softirq_init();
 618        timekeeping_init();
 619        time_init();
 620        profile_init();
 621        if (!irqs_disabled())
 622                printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 623                                 "enabled early\n");
 624        early_boot_irqs_on();
 625        local_irq_enable();
 626
 627        /* Interrupts are enabled now so all GFP allocations are safe. */
 628        gfp_allowed_mask = __GFP_BITS_MASK;
 629
 630        kmem_cache_init_late();
 631
 632        /*
 633         * HACK ALERT! This is early. We're enabling the console before
 634         * we've done PCI setups etc, and console_init() must be aware of
 635         * this. But we do want output early, in case something goes wrong.
 636         */
 637        console_init();
 638        if (panic_later)
 639                panic(panic_later, panic_param);
 640
 641        lockdep_info();
 642
 643        /*
 644         * Need to run this when irqs are enabled, because it wants
 645         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 646         * too:
 647         */
 648        locking_selftest();
 649
 650#ifdef CONFIG_BLK_DEV_INITRD
 651        if (initrd_start && !initrd_below_start_ok &&
 652            page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 653                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 654                    "disabling it.\n",
 655                    page_to_pfn(virt_to_page((void *)initrd_start)),
 656                    min_low_pfn);
 657                initrd_start = 0;
 658        }
 659#endif
 660        page_cgroup_init();
 661        enable_debug_pagealloc();
 662        kmemleak_init();
 663        debug_objects_mem_init();
 664        idr_init_cache();
 665        setup_per_cpu_pageset();
 666        numa_policy_init();
 667        if (late_time_init)
 668                late_time_init();
 669        sched_clock_init();
 670        calibrate_delay();
 671        pidmap_init();
 672        anon_vma_init();
 673#ifdef CONFIG_X86
 674        if (efi_enabled)
 675                efi_enter_virtual_mode();
 676#endif
 677        thread_info_cache_init();
 678        cred_init();
 679        fork_init(totalram_pages);
 680        proc_caches_init();
 681        buffer_init();
 682        key_init();
 683        security_init();
 684        dbg_late_init();
 685        vfs_caches_init(totalram_pages);
 686        signals_init();
 687        /* rootfs populating might need page-writeback */
 688        page_writeback_init();
 689#ifdef CONFIG_PROC_FS
 690        proc_root_init();
 691#endif
 692        cgroup_init();
 693        cpuset_init();
 694        taskstats_init_early();
 695        delayacct_init();
 696
 697        check_bugs();
 698
 699        acpi_early_init(); /* before LAPIC and SMP init */
 700        sfi_init_late();
 701
 702        ftrace_init();
 703
 704        /* Do the rest non-__init'ed, we're now alive */
 705        rest_init();
 706}
 707
 708/* Call all constructor functions linked into the kernel. */
 709static void __init do_ctors(void)
 710{
 711#ifdef CONFIG_CONSTRUCTORS
 712        ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 713
 714        for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 715                (*fn)();
 716#endif
 717}
 718
 719int initcall_debug;
 720core_param(initcall_debug, initcall_debug, bool, 0644);
 721
 722static char msgbuf[64];
 723
 724static int __init_or_module do_one_initcall_debug(initcall_t fn)
 725{
 726        ktime_t calltime, delta, rettime;
 727        unsigned long long duration;
 728        int ret;
 729
 730        printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 731        calltime = ktime_get();
 732        ret = fn();
 733        rettime = ktime_get();
 734        delta = ktime_sub(rettime, calltime);
 735        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 736        printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 737                ret, duration);
 738
 739        return ret;
 740}
 741
 742int __init_or_module do_one_initcall(initcall_t fn)
 743{
 744        int count = preempt_count();
 745        int ret;
 746
 747        if (initcall_debug)
 748                ret = do_one_initcall_debug(fn);
 749        else
 750                ret = fn();
 751
 752        msgbuf[0] = 0;
 753
 754        if (ret && ret != -ENODEV && initcall_debug)
 755                sprintf(msgbuf, "error code %d ", ret);
 756
 757        if (preempt_count() != count) {
 758                strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 759                preempt_count() = count;
 760        }
 761        if (irqs_disabled()) {
 762                strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 763                local_irq_enable();
 764        }
 765        if (msgbuf[0]) {
 766                printk("initcall %pF returned with %s\n", fn, msgbuf);
 767        }
 768
 769        return ret;
 770}
 771
 772
 773extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
 774
 775static void __init do_initcalls(void)
 776{
 777        initcall_t *fn;
 778
 779        for (fn = __early_initcall_end; fn < __initcall_end; fn++)
 780                do_one_initcall(*fn);
 781
 782        /* Make sure there is no pending stuff from the initcall sequence */
 783        flush_scheduled_work();
 784}
 785
 786/*
 787 * Ok, the machine is now initialized. None of the devices
 788 * have been touched yet, but the CPU subsystem is up and
 789 * running, and memory and process management works.
 790 *
 791 * Now we can finally start doing some real work..
 792 */
 793static void __init do_basic_setup(void)
 794{
 795        cpuset_init_smp();
 796        usermodehelper_init();
 797        init_tmpfs();
 798        driver_init();
 799        init_irq_proc();
 800        do_ctors();
 801        do_initcalls();
 802}
 803
 804static void __init do_pre_smp_initcalls(void)
 805{
 806        initcall_t *fn;
 807
 808        for (fn = __initcall_start; fn < __early_initcall_end; fn++)
 809                do_one_initcall(*fn);
 810}
 811
 812static void run_init_process(const char *init_filename)
 813{
 814        argv_init[0] = init_filename;
 815        kernel_execve(init_filename, argv_init, envp_init);
 816}
 817
 818/* This is a non __init function. Force it to be noinline otherwise gcc
 819 * makes it inline to init() and it becomes part of init.text section
 820 */
 821static noinline int init_post(void)
 822        __releases(kernel_lock)
 823{
 824        /* need to finish all async __init code before freeing the memory */
 825        async_synchronize_full();
 826        free_initmem();
 827        mark_rodata_ro();
 828        system_state = SYSTEM_RUNNING;
 829        numa_default_policy();
 830
 831
 832        current->signal->flags |= SIGNAL_UNKILLABLE;
 833
 834        if (ramdisk_execute_command) {
 835                run_init_process(ramdisk_execute_command);
 836                printk(KERN_WARNING "Failed to execute %s\n",
 837                                ramdisk_execute_command);
 838        }
 839
 840        /*
 841         * We try each of these until one succeeds.
 842         *
 843         * The Bourne shell can be used instead of init if we are
 844         * trying to recover a really broken machine.
 845         */
 846        if (execute_command) {
 847                run_init_process(execute_command);
 848                printk(KERN_WARNING "Failed to execute %s.  Attempting "
 849                                        "defaults...\n", execute_command);
 850        }
 851        run_init_process("/sbin/init");
 852        run_init_process("/etc/init");
 853        run_init_process("/bin/init");
 854        run_init_process("/bin/sh");
 855
 856        panic("No init found.  Try passing init= option to kernel. "
 857              "See Linux Documentation/init.txt for guidance.");
 858}
 859
 860static int __init kernel_init(void * unused)
 861{
 862        /*
 863         * Wait until kthreadd is all set-up.
 864         */
 865        wait_for_completion(&kthreadd_done);
 866        /*
 867         * init can allocate pages on any node
 868         */
 869        set_mems_allowed(node_states[N_HIGH_MEMORY]);
 870        /*
 871         * init can run on any cpu.
 872         */
 873        set_cpus_allowed_ptr(current, cpu_all_mask);
 874        /*
 875         * Tell the world that we're going to be the grim
 876         * reaper of innocent orphaned children.
 877         *
 878         * We don't want people to have to make incorrect
 879         * assumptions about where in the task array this
 880         * can be found.
 881         */
 882        init_pid_ns.child_reaper = current;
 883
 884        cad_pid = task_pid(current);
 885
 886        smp_prepare_cpus(setup_max_cpus);
 887
 888        do_pre_smp_initcalls();
 889
 890        smp_init();
 891        sched_init_smp();
 892
 893        do_basic_setup();
 894
 895        /* Open the /dev/console on the rootfs, this should never fail */
 896        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 897                printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 898
 899        (void) sys_dup(0);
 900        (void) sys_dup(0);
 901        /*
 902         * check if there is an early userspace init.  If yes, let it do all
 903         * the work
 904         */
 905
 906        if (!ramdisk_execute_command)
 907                ramdisk_execute_command = "/init";
 908
 909        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 910                ramdisk_execute_command = NULL;
 911                prepare_namespace();
 912        }
 913
 914        /*
 915         * Ok, we have completed the initial bootup, and
 916         * we're essentially up and running. Get rid of the
 917         * initmem segments and start the user-mode stuff..
 918         */
 919
 920        init_post();
 921        return 0;
 922}
 923
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