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