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#include <linux/blkdev.h>
  74#include <linux/elevator.h>
  75
  76#include <asm/io.h>
  77#include <asm/bugs.h>
  78#include <asm/setup.h>
  79#include <asm/sections.h>
  80#include <asm/cacheflush.h>
  81
  82#ifdef CONFIG_X86_LOCAL_APIC
  83#include <asm/smp.h>
  84#endif
  85
  86static int kernel_init(void *);
  87
  88extern void init_IRQ(void);
  89extern void fork_init(unsigned long);
  90extern void mca_init(void);
  91extern void sbus_init(void);
  92extern void radix_tree_init(void);
  93#ifndef CONFIG_DEBUG_RODATA
  94static inline void mark_rodata_ro(void) { }
  95#endif
  96
  97#ifdef CONFIG_TC
  98extern void tc_init(void);
  99#endif
 100
 101/*
 102 * Debug helper: via this flag we know that we are in 'early bootup code'
 103 * where only the boot processor is running with IRQ disabled.  This means
 104 * two things - IRQ must not be enabled before the flag is cleared and some
 105 * operations which are not allowed with IRQ disabled are allowed while the
 106 * flag is set.
 107 */
 108bool early_boot_irqs_disabled __read_mostly;
 109
 110enum system_states system_state __read_mostly;
 111EXPORT_SYMBOL(system_state);
 112
 113/*
 114 * Boot command-line arguments
 115 */
 116#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 117#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 118
 119extern void time_init(void);
 120/* Default late time init is NULL. archs can override this later. */
 121void (*__initdata late_time_init)(void);
 122extern void softirq_init(void);
 123
 124/* Untouched command line saved by arch-specific code. */
 125char __initdata boot_command_line[COMMAND_LINE_SIZE];
 126/* Untouched saved command line (eg. for /proc) */
 127char *saved_command_line;
 128/* Command line for parameter parsing */
 129static char *static_command_line;
 130
 131static char *execute_command;
 132static char *ramdisk_execute_command;
 133
 134/*
 135 * If set, this is an indication to the drivers that reset the underlying
 136 * device before going ahead with the initialization otherwise driver might
 137 * rely on the BIOS and skip the reset operation.
 138 *
 139 * This is useful if kernel is booting in an unreliable environment.
 140 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 141 * skipped and devices will be in unknown state.
 142 */
 143unsigned int reset_devices;
 144EXPORT_SYMBOL(reset_devices);
 145
 146static int __init set_reset_devices(char *str)
 147{
 148        reset_devices = 1;
 149        return 1;
 150}
 151
 152__setup("reset_devices", set_reset_devices);
 153
 154static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 155const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 156static const char *panic_later, *panic_param;
 157
 158extern const struct obs_kernel_param __setup_start[], __setup_end[];
 159
 160static int __init obsolete_checksetup(char *line)
 161{
 162        const struct obs_kernel_param *p;
 163        int had_early_param = 0;
 164
 165        p = __setup_start;
 166        do {
 167                int n = strlen(p->str);
 168                if (parameqn(line, p->str, n)) {
 169                        if (p->early) {
 170                                /* Already done in parse_early_param?
 171                                 * (Needs exact match on param part).
 172                                 * Keep iterating, as we can have early
 173                                 * params and __setups of same names 8( */
 174                                if (line[n] == '\0' || line[n] == '=')
 175                                        had_early_param = 1;
 176                        } else if (!p->setup_func) {
 177                                printk(KERN_WARNING "Parameter %s is obsolete,"
 178                                       " ignored\n", p->str);
 179                                return 1;
 180                        } else if (p->setup_func(line + n))
 181                                return 1;
 182                }
 183                p++;
 184        } while (p < __setup_end);
 185
 186        return had_early_param;
 187}
 188
 189/*
 190 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 191 * still work even if initially too large, it will just take slightly longer
 192 */
 193unsigned long loops_per_jiffy = (1<<12);
 194
 195EXPORT_SYMBOL(loops_per_jiffy);
 196
 197static int __init debug_kernel(char *str)
 198{
 199        console_loglevel = 10;
 200        return 0;
 201}
 202
 203static int __init quiet_kernel(char *str)
 204{
 205        console_loglevel = 4;
 206        return 0;
 207}
 208
 209early_param("debug", debug_kernel);
 210early_param("quiet", quiet_kernel);
 211
 212static int __init loglevel(char *str)
 213{
 214        int newlevel;
 215
 216        /*
 217         * Only update loglevel value when a correct setting was passed,
 218         * to prevent blind crashes (when loglevel being set to 0) that
 219         * are quite hard to debug
 220         */
 221        if (get_option(&str, &newlevel)) {
 222                console_loglevel = newlevel;
 223                return 0;
 224        }
 225
 226        return -EINVAL;
 227}
 228
 229early_param("loglevel", loglevel);
 230
 231/* Change NUL term back to "=", to make "param" the whole string. */
 232static int __init repair_env_string(char *param, char *val, const char *unused)
 233{
 234        if (val) {
 235                /* param=val or param="val"? */
 236                if (val == param+strlen(param)+1)
 237                        val[-1] = '=';
 238                else if (val == param+strlen(param)+2) {
 239                        val[-2] = '=';
 240                        memmove(val-1, val, strlen(val)+1);
 241                        val--;
 242                } else
 243                        BUG();
 244        }
 245        return 0;
 246}
 247
 248/*
 249 * Unknown boot options get handed to init, unless they look like
 250 * unused parameters (modprobe will find them in /proc/cmdline).
 251 */
 252static int __init unknown_bootoption(char *param, char *val, const char *unused)
 253{
 254        repair_env_string(param, val, unused);
 255
 256        /* Handle obsolete-style parameters */
 257        if (obsolete_checksetup(param))
 258                return 0;
 259
 260        /* Unused module parameter. */
 261        if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 262                return 0;
 263
 264        if (panic_later)
 265                return 0;
 266
 267        if (val) {
 268                /* Environment option */
 269                unsigned int i;
 270                for (i = 0; envp_init[i]; i++) {
 271                        if (i == MAX_INIT_ENVS) {
 272                                panic_later = "Too many boot env vars at `%s'";
 273                                panic_param = param;
 274                        }
 275                        if (!strncmp(param, envp_init[i], val - param))
 276                                break;
 277                }
 278                envp_init[i] = param;
 279        } else {
 280                /* Command line option */
 281                unsigned int i;
 282                for (i = 0; argv_init[i]; i++) {
 283                        if (i == MAX_INIT_ARGS) {
 284                                panic_later = "Too many boot init vars at `%s'";
 285                                panic_param = param;
 286                        }
 287                }
 288                argv_init[i] = param;
 289        }
 290        return 0;
 291}
 292
 293static int __init init_setup(char *str)
 294{
 295        unsigned int i;
 296
 297        execute_command = str;
 298        /*
 299         * In case LILO is going to boot us with default command line,
 300         * it prepends "auto" before the whole cmdline which makes
 301         * the shell think it should execute a script with such name.
 302         * So we ignore all arguments entered _before_ init=... [MJ]
 303         */
 304        for (i = 1; i < MAX_INIT_ARGS; i++)
 305                argv_init[i] = NULL;
 306        return 1;
 307}
 308__setup("init=", init_setup);
 309
 310static int __init rdinit_setup(char *str)
 311{
 312        unsigned int i;
 313
 314        ramdisk_execute_command = str;
 315        /* See "auto" comment in init_setup */
 316        for (i = 1; i < MAX_INIT_ARGS; i++)
 317                argv_init[i] = NULL;
 318        return 1;
 319}
 320__setup("rdinit=", rdinit_setup);
 321
 322#ifndef CONFIG_SMP
 323static const unsigned int setup_max_cpus = NR_CPUS;
 324#ifdef CONFIG_X86_LOCAL_APIC
 325static void __init smp_init(void)
 326{
 327        APIC_init_uniprocessor();
 328}
 329#else
 330#define smp_init()      do { } while (0)
 331#endif
 332
 333static inline void setup_nr_cpu_ids(void) { }
 334static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 335#endif
 336
 337/*
 338 * We need to store the untouched command line for future reference.
 339 * We also need to store the touched command line since the parameter
 340 * parsing is performed in place, and we should allow a component to
 341 * store reference of name/value for future reference.
 342 */
 343static void __init setup_command_line(char *command_line)
 344{
 345        saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 346        static_command_line = alloc_bootmem(strlen (command_line)+1);
 347        strcpy (saved_command_line, boot_command_line);
 348        strcpy (static_command_line, command_line);
 349}
 350
 351/*
 352 * We need to finalize in a non-__init function or else race conditions
 353 * between the root thread and the init thread may cause start_kernel to
 354 * be reaped by free_initmem before the root thread has proceeded to
 355 * cpu_idle.
 356 *
 357 * gcc-3.4 accidentally inlines this function, so use noinline.
 358 */
 359
 360static __initdata DECLARE_COMPLETION(kthreadd_done);
 361
 362static noinline void __init_refok rest_init(void)
 363{
 364        int pid;
 365
 366        rcu_scheduler_starting();
 367        /*
 368         * We need to spawn init first so that it obtains pid 1, however
 369         * the init task will end up wanting to create kthreads, which, if
 370         * we schedule it before we create kthreadd, will OOPS.
 371         */
 372        kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 373        numa_default_policy();
 374        pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 375        rcu_read_lock();
 376        kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 377        rcu_read_unlock();
 378        complete(&kthreadd_done);
 379
 380        /*
 381         * The boot idle thread must execute schedule()
 382         * at least once to get things moving:
 383         */
 384        init_idle_bootup_task(current);
 385        schedule_preempt_disabled();
 386        /* Call into cpu_idle with preempt disabled */
 387        cpu_idle();
 388}
 389
 390/* Check for early params. */
 391static int __init do_early_param(char *param, char *val, const char *unused)
 392{
 393        const struct obs_kernel_param *p;
 394
 395        for (p = __setup_start; p < __setup_end; p++) {
 396                if ((p->early && parameq(param, p->str)) ||
 397                    (strcmp(param, "console") == 0 &&
 398                     strcmp(p->str, "earlycon") == 0)
 399                ) {
 400                        if (p->setup_func(val) != 0)
 401                                printk(KERN_WARNING
 402                                       "Malformed early option '%s'\n", param);
 403                }
 404        }
 405        /* We accept everything at this stage. */
 406        return 0;
 407}
 408
 409void __init parse_early_options(char *cmdline)
 410{
 411        parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 412}
 413
 414/* Arch code calls this early on, or if not, just before other parsing. */
 415void __init parse_early_param(void)
 416{
 417        static __initdata int done = 0;
 418        static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 419
 420        if (done)
 421                return;
 422
 423        /* All fall through to do_early_param. */
 424        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 425        parse_early_options(tmp_cmdline);
 426        done = 1;
 427}
 428
 429/*
 430 *      Activate the first processor.
 431 */
 432
 433static void __init boot_cpu_init(void)
 434{
 435        int cpu = smp_processor_id();
 436        /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 437        set_cpu_online(cpu, true);
 438        set_cpu_active(cpu, true);
 439        set_cpu_present(cpu, true);
 440        set_cpu_possible(cpu, true);
 441}
 442
 443void __init __weak smp_setup_processor_id(void)
 444{
 445}
 446
 447# if THREAD_SIZE >= PAGE_SIZE
 448void __init __weak thread_info_cache_init(void)
 449{
 450}
 451#endif
 452
 453/*
 454 * Set up kernel memory allocators
 455 */
 456static void __init mm_init(void)
 457{
 458        /*
 459         * page_cgroup requires contiguous pages,
 460         * bigger than MAX_ORDER unless SPARSEMEM.
 461         */
 462        page_cgroup_init_flatmem();
 463        mem_init();
 464        kmem_cache_init();
 465        percpu_init_late();
 466        pgtable_cache_init();
 467        vmalloc_init();
 468}
 469
 470asmlinkage void __init start_kernel(void)
 471{
 472        char * command_line;
 473        extern const struct kernel_param __start___param[], __stop___param[];
 474
 475        /*
 476         * Need to run as early as possible, to initialize the
 477         * lockdep hash:
 478         */
 479        lockdep_init();
 480        smp_setup_processor_id();
 481        debug_objects_early_init();
 482
 483        /*
 484         * Set up the the initial canary ASAP:
 485         */
 486        boot_init_stack_canary();
 487
 488        cgroup_init_early();
 489
 490        local_irq_disable();
 491        early_boot_irqs_disabled = true;
 492
 493/*
 494 * Interrupts are still disabled. Do necessary setups, then
 495 * enable them
 496 */
 497        tick_init();
 498        boot_cpu_init();
 499        page_address_init();
 500        printk(KERN_NOTICE "%s", linux_banner);
 501        setup_arch(&command_line);
 502        mm_init_owner(&init_mm, &init_task);
 503        mm_init_cpumask(&init_mm);
 504        setup_command_line(command_line);
 505        setup_nr_cpu_ids();
 506        setup_per_cpu_areas();
 507        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 508
 509        build_all_zonelists(NULL, NULL);
 510        page_alloc_init();
 511
 512        printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 513        parse_early_param();
 514        parse_args("Booting kernel", static_command_line, __start___param,
 515                   __stop___param - __start___param,
 516                   -1, -1, &unknown_bootoption);
 517
 518        jump_label_init();
 519
 520        /*
 521         * These use large bootmem allocations and must precede
 522         * kmem_cache_init()
 523         */
 524        setup_log_buf(0);
 525        pidhash_init();
 526        vfs_caches_init_early();
 527        sort_main_extable();
 528        trap_init();
 529        mm_init();
 530
 531        /*
 532         * Set up the scheduler prior starting any interrupts (such as the
 533         * timer interrupt). Full topology setup happens at smp_init()
 534         * time - but meanwhile we still have a functioning scheduler.
 535         */
 536        sched_init();
 537        /*
 538         * Disable preemption - early bootup scheduling is extremely
 539         * fragile until we cpu_idle() for the first time.
 540         */
 541        preempt_disable();
 542        if (!irqs_disabled()) {
 543                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 544                                "enabled *very* early, fixing it\n");
 545                local_irq_disable();
 546        }
 547        idr_init_cache();
 548        perf_event_init();
 549        rcu_init();
 550        radix_tree_init();
 551        /* init some links before init_ISA_irqs() */
 552        early_irq_init();
 553        init_IRQ();
 554        init_timers();
 555        hrtimers_init();
 556        softirq_init();
 557        timekeeping_init();
 558        time_init();
 559        profile_init();
 560        call_function_init();
 561        if (!irqs_disabled())
 562                printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 563                                 "enabled early\n");
 564        early_boot_irqs_disabled = false;
 565        local_irq_enable();
 566
 567        kmem_cache_init_late();
 568
 569        /*
 570         * HACK ALERT! This is early. We're enabling the console before
 571         * we've done PCI setups etc, and console_init() must be aware of
 572         * this. But we do want output early, in case something goes wrong.
 573         */
 574        console_init();
 575        if (panic_later)
 576                panic(panic_later, panic_param);
 577
 578        lockdep_info();
 579
 580        /*
 581         * Need to run this when irqs are enabled, because it wants
 582         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 583         * too:
 584         */
 585        locking_selftest();
 586
 587#ifdef CONFIG_BLK_DEV_INITRD
 588        if (initrd_start && !initrd_below_start_ok &&
 589            page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 590                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 591                    "disabling it.\n",
 592                    page_to_pfn(virt_to_page((void *)initrd_start)),
 593                    min_low_pfn);
 594                initrd_start = 0;
 595        }
 596#endif
 597        page_cgroup_init();
 598        debug_objects_mem_init();
 599        kmemleak_init();
 600        setup_per_cpu_pageset();
 601        numa_policy_init();
 602        if (late_time_init)
 603                late_time_init();
 604        sched_clock_init();
 605        calibrate_delay();
 606        pidmap_init();
 607        anon_vma_init();
 608#ifdef CONFIG_X86
 609        if (efi_enabled(EFI_RUNTIME_SERVICES))
 610                efi_enter_virtual_mode();
 611#endif
 612        thread_info_cache_init();
 613        cred_init();
 614        fork_init(totalram_pages);
 615        proc_caches_init();
 616        buffer_init();
 617        key_init();
 618        security_init();
 619        dbg_late_init();
 620        vfs_caches_init(totalram_pages);
 621        signals_init();
 622        /* rootfs populating might need page-writeback */
 623        page_writeback_init();
 624#ifdef CONFIG_PROC_FS
 625        proc_root_init();
 626#endif
 627        cgroup_init();
 628        cpuset_init();
 629        taskstats_init_early();
 630        delayacct_init();
 631
 632        check_bugs();
 633
 634        acpi_early_init(); /* before LAPIC and SMP init */
 635        sfi_init_late();
 636
 637        if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 638                efi_late_init();
 639                efi_free_boot_services();
 640        }
 641
 642        ftrace_init();
 643
 644        /* Do the rest non-__init'ed, we're now alive */
 645        rest_init();
 646}
 647
 648/* Call all constructor functions linked into the kernel. */
 649static void __init do_ctors(void)
 650{
 651#ifdef CONFIG_CONSTRUCTORS
 652        ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 653
 654        for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 655                (*fn)();
 656#endif
 657}
 658
 659bool initcall_debug;
 660core_param(initcall_debug, initcall_debug, bool, 0644);
 661
 662static char msgbuf[64];
 663
 664static int __init_or_module do_one_initcall_debug(initcall_t fn)
 665{
 666        ktime_t calltime, delta, rettime;
 667        unsigned long long duration;
 668        int ret;
 669
 670        printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 671        calltime = ktime_get();
 672        ret = fn();
 673        rettime = ktime_get();
 674        delta = ktime_sub(rettime, calltime);
 675        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 676        printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 677                ret, duration);
 678
 679        return ret;
 680}
 681
 682int __init_or_module do_one_initcall(initcall_t fn)
 683{
 684        int count = preempt_count();
 685        int ret;
 686
 687        if (initcall_debug)
 688                ret = do_one_initcall_debug(fn);
 689        else
 690                ret = fn();
 691
 692        msgbuf[0] = 0;
 693
 694        if (ret && ret != -ENODEV && initcall_debug)
 695                sprintf(msgbuf, "error code %d ", ret);
 696
 697        if (preempt_count() != count) {
 698                strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 699                preempt_count() = count;
 700        }
 701        if (irqs_disabled()) {
 702                strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 703                local_irq_enable();
 704        }
 705        if (msgbuf[0]) {
 706                printk("initcall %pF returned with %s\n", fn, msgbuf);
 707        }
 708
 709        return ret;
 710}
 711
 712
 713extern initcall_t __initcall_start[];
 714extern initcall_t __initcall0_start[];
 715extern initcall_t __initcall1_start[];
 716extern initcall_t __initcall2_start[];
 717extern initcall_t __initcall3_start[];
 718extern initcall_t __initcall4_start[];
 719extern initcall_t __initcall5_start[];
 720extern initcall_t __initcall6_start[];
 721extern initcall_t __initcall7_start[];
 722extern initcall_t __initcall_end[];
 723
 724static initcall_t *initcall_levels[] __initdata = {
 725        __initcall0_start,
 726        __initcall1_start,
 727        __initcall2_start,
 728        __initcall3_start,
 729        __initcall4_start,
 730        __initcall5_start,
 731        __initcall6_start,
 732        __initcall7_start,
 733        __initcall_end,
 734};
 735
 736/* Keep these in sync with initcalls in include/linux/init.h */
 737static char *initcall_level_names[] __initdata = {
 738        "early",
 739        "core",
 740        "postcore",
 741        "arch",
 742        "subsys",
 743        "fs",
 744        "device",
 745        "late",
 746};
 747
 748static void __init do_initcall_level(int level)
 749{
 750        extern const struct kernel_param __start___param[], __stop___param[];
 751        initcall_t *fn;
 752
 753        strcpy(static_command_line, saved_command_line);
 754        parse_args(initcall_level_names[level],
 755                   static_command_line, __start___param,
 756                   __stop___param - __start___param,
 757                   level, level,
 758                   &repair_env_string);
 759
 760        for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 761                do_one_initcall(*fn);
 762}
 763
 764static void __init do_initcalls(void)
 765{
 766        int level;
 767
 768        for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 769                do_initcall_level(level);
 770}
 771
 772/*
 773 * Ok, the machine is now initialized. None of the devices
 774 * have been touched yet, but the CPU subsystem is up and
 775 * running, and memory and process management works.
 776 *
 777 * Now we can finally start doing some real work..
 778 */
 779static void __init do_basic_setup(void)
 780{
 781        cpuset_init_smp();
 782        usermodehelper_init();
 783        shmem_init();
 784        driver_init();
 785        init_irq_proc();
 786        do_ctors();
 787        usermodehelper_enable();
 788        do_initcalls();
 789}
 790
 791static void __init do_pre_smp_initcalls(void)
 792{
 793        initcall_t *fn;
 794
 795        for (fn = __initcall_start; fn < __initcall0_start; fn++)
 796                do_one_initcall(*fn);
 797}
 798
 799/*
 800 * This function requests modules which should be loaded by default and is
 801 * called twice right after initrd is mounted and right before init is
 802 * exec'd.  If such modules are on either initrd or rootfs, they will be
 803 * loaded before control is passed to userland.
 804 */
 805void __init load_default_modules(void)
 806{
 807        load_default_elevator_module();
 808}
 809
 810static int run_init_process(const char *init_filename)
 811{
 812        argv_init[0] = init_filename;
 813        return do_execve(init_filename,
 814                (const char __user *const __user *)argv_init,
 815                (const char __user *const __user *)envp_init);
 816}
 817
 818static noinline void __init kernel_init_freeable(void);
 819
 820static int __ref kernel_init(void *unused)
 821{
 822        kernel_init_freeable();
 823        /* need to finish all async __init code before freeing the memory */
 824        async_synchronize_full();
 825        free_initmem();
 826        mark_rodata_ro();
 827        system_state = SYSTEM_RUNNING;
 828        numa_default_policy();
 829
 830        flush_delayed_fput();
 831
 832        if (ramdisk_execute_command) {
 833                if (!run_init_process(ramdisk_execute_command))
 834                        return 0;
 835                printk(KERN_WARNING "Failed to execute %s\n",
 836                                ramdisk_execute_command);
 837        }
 838
 839        /*
 840         * We try each of these until one succeeds.
 841         *
 842         * The Bourne shell can be used instead of init if we are
 843         * trying to recover a really broken machine.
 844         */
 845        if (execute_command) {
 846                if (!run_init_process(execute_command))
 847                        return 0;
 848                printk(KERN_WARNING "Failed to execute %s.  Attempting "
 849                                        "defaults...\n", execute_command);
 850        }
 851        if (!run_init_process("/sbin/init") ||
 852            !run_init_process("/etc/init") ||
 853            !run_init_process("/bin/init") ||
 854            !run_init_process("/bin/sh"))
 855                return 0;
 856
 857        panic("No init found.  Try passing init= option to kernel. "
 858              "See Linux Documentation/init.txt for guidance.");
 859}
 860
 861static noinline void __init kernel_init_freeable(void)
 862{
 863        /*
 864         * Wait until kthreadd is all set-up.
 865         */
 866        wait_for_completion(&kthreadd_done);
 867
 868        /* Now the scheduler is fully set up and can do blocking allocations */
 869        gfp_allowed_mask = __GFP_BITS_MASK;
 870
 871        /*
 872         * init can allocate pages on any node
 873         */
 874        set_mems_allowed(node_states[N_MEMORY]);
 875        /*
 876         * init can run on any cpu.
 877         */
 878        set_cpus_allowed_ptr(current, cpu_all_mask);
 879
 880        cad_pid = task_pid(current);
 881
 882        smp_prepare_cpus(setup_max_cpus);
 883
 884        do_pre_smp_initcalls();
 885        lockup_detector_init();
 886
 887        smp_init();
 888        sched_init_smp();
 889
 890        do_basic_setup();
 891
 892        /* Open the /dev/console on the rootfs, this should never fail */
 893        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 894                printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 895
 896        (void) sys_dup(0);
 897        (void) sys_dup(0);
 898        /*
 899         * check if there is an early userspace init.  If yes, let it do all
 900         * the work
 901         */
 902
 903        if (!ramdisk_execute_command)
 904                ramdisk_execute_command = "/init";
 905
 906        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 907                ramdisk_execute_command = NULL;
 908                prepare_namespace();
 909        }
 910
 911        /*
 912         * Ok, we have completed the initial bootup, and
 913         * we're essentially up and running. Get rid of the
 914         * initmem segments and start the user-mode stuff..
 915         */
 916
 917        /* rootfs is available now, try loading default modules */
 918        load_default_modules();
 919}
 920
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