asmlinkage void __init start_kernel(void)
{
        char * command_line;
        extern struct kernel_param __start___param[], __stop___param[];

        smp_setup_processor_id();



        /*
         * Need to run as early as possible, to initialize the
         * lockdep hash:
         */
        unwind_init();
        lockdep_init();
                /*K lockdep은, runtime에 lock들의 correctness를
                 * 보장해 주기 위한 도구이다.
                 *  이 도구는 lock들의 '클래스'에 대해 작동한다.
                 * 여기서 클래스란 locking rules 라는 면에 있어서
                 * 동일한 lock들의 그룹이다.
                 *  이 도구는 lock 클래스들의 상태(state)와 의존성
                 * (dependency)를 track한다. 그리고 이 상태와 의존성
                 * 들이 올바름을 확인한다.
                 *  자세한 것은 Documentation/lockdep-design.txt
                 * 를 참고할 것. CONFIG_LOCKDEP이 정의되어 있지 않으면
                 * lockdep 관련 기능들은 컴파일되지 않는다. */

        local_irq_disable();
        early_boot_irqs_off();
        early_init_irq_lock_class();

/*
* Interrupts are still disabled. Do necessary setups, then
* enable them
*/
        lock_kernel();
        boot_cpu_init();
        page_address_init();
        printk(KERN_NOTICE);
        printk(linux_banner);
        setup_arch(&command_line);


        /////////////////////////////// 1

        unwind_setup();
        setup_per_cpu_areas();
        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */

        /*
         * Set up the scheduler prior starting any interrupts (such as the
         * timer interrupt). Full topology setup happens at smp_init()
         * time - but meanwhile we still have a functioning scheduler.
         */
        sched_init();
        /*
         * Disable preemption - early bootup scheduling is extremely * fragile until we cpu_idle() for the first time.  */
        preempt_disable();
        build_all_zonelists();
        page_alloc_init();
        printk(KERN_NOTICE "Kernel command line: %sn", saved_command_line);
        parse_early_param();
        parse_args("Booting kernel", command_line, __start___param,
                   __stop___param - __start___param,
                   &unknown_bootoption);
        if (!irqs_disabled()) {
                printk(KERN_WARNING "start_kernel(): bug: interrupts were "
                                "enabled *very* early, fixing itn");
                local_irq_disable();
        }

        //////////////////////////// 2

        sort_main_extable();
        trap_init();
        rcu_init();
        init_IRQ();
        pidhash_init();

        ///////////////////////////// 3

        init_timers();
        hrtimers_init();
        softirq_init();
        timekeeping_init();
        time_init();
        profile_init();
        if (!irqs_disabled())
                printk("start_kernel(): bug: interrupts were enabled earlyn");
        early_boot_irqs_on();
        local_irq_enable();

        //////////////////////////// 4

        /*
         * HACK ALERT! This is early. We're enabling the console before
         * we've done PCI setups etc, and console_init() must be aware of
         * this. But we do want output early, in case something goes wrong.
         */
        console_init();
        if (panic_later)
                panic(panic_later, panic_param);

        lockdep_info();

        /*
         * Need to run this when irqs are enabled, because it wants
         * to self-test [hard/soft]-irqs on/off lock inversion bugs
         * too:
         */
        locking_selftest();

#ifdef CONFIG_BLK_DEV_INITRD
        if (initrd_start && !initrd_below_start_ok &&
                        initrd_start < min_low_pfn << PAGE_SHIFT) {
                printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
                    "disabling it.n",initrd_start,min_low_pfn << PAGE_SHIFT);
                initrd_start = 0;
        }
#endif
        vfs_caches_init_early();
        cpuset_init_early();
        mem_init();
        kmem_cache_init();

        ////////////////////////////// 5

        setup_per_cpu_pageset();
        numa_policy_init();
        if (late_time_init)
                late_time_init();
        calibrate_delay();
        pidmap_init();
        pgtable_cache_init();
        prio_tree_init();
        anon_vma_init();
#ifdef CONFIG_X86
        if (efi_enabled)
                efi_enter_virtual_mode();
#endif
        fork_init(num_physpages);
        proc_caches_init();
        buffer_init();
        unnamed_dev_init();
        key_init();
        security_init();
        vfs_caches_init(num_physpages);

        ////////////////////////////// 6

        radix_tree_init();
        signals_init();
        /* rootfs populating might need page-writeback */
        page_writeback_init();
#ifdef CONFIG_PROC_FS
        proc_root_init();
#endif
        cpuset_init();
        taskstats_init_early();
        delayacct_init();

        check_bugs();

        acpi_early_init(); /* before LAPIC and SMP init */

        /* Do the rest non-__init'ed, we're now alive */
        rest_init();

        //////////////////////////////////// 7
}