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#define DEBUG           /* Enable initcall_debug */
  13
  14#include <linux/types.h>
  15#include <linux/module.h>
  16#include <linux/proc_fs.h>
  17#include <linux/kernel.h>
  18#include <linux/syscalls.h>
  19#include <linux/stackprotector.h>
  20#include <linux/string.h>
  21#include <linux/ctype.h>
  22#include <linux/delay.h>
  23#include <linux/ioport.h>
  24#include <linux/init.h>
  25#include <linux/initrd.h>
  26#include <linux/bootmem.h>
  27#include <linux/acpi.h>
  28#include <linux/tty.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/profile.h>
  37#include <linux/rcupdate.h>
  38#include <linux/moduleparam.h>
  39#include <linux/kallsyms.h>
  40#include <linux/writeback.h>
  41#include <linux/cpu.h>
  42#include <linux/cpuset.h>
  43#include <linux/cgroup.h>
  44#include <linux/efi.h>
  45#include <linux/tick.h>
  46#include <linux/interrupt.h>
  47#include <linux/taskstats_kern.h>
  48#include <linux/delayacct.h>
  49#include <linux/unistd.h>
  50#include <linux/rmap.h>
  51#include <linux/mempolicy.h>
  52#include <linux/key.h>
  53#include <linux/buffer_head.h>
  54#include <linux/page_ext.h>
  55#include <linux/debug_locks.h>
  56#include <linux/debugobjects.h>
  57#include <linux/lockdep.h>
  58#include <linux/kmemleak.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/kgdb.h>
  66#include <linux/ftrace.h>
  67#include <linux/async.h>
  68#include <linux/kmemcheck.h>
  69#include <linux/sfi.h>
  70#include <linux/shmem_fs.h>
  71#include <linux/slab.h>
  72#include <linux/perf_event.h>
  73#include <linux/file.h>
  74#include <linux/ptrace.h>
  75#include <linux/blkdev.h>
  76#include <linux/elevator.h>
  77#include <linux/sched_clock.h>
  78#include <linux/context_tracking.h>
  79#include <linux/random.h>
  80#include <linux/list.h>
  81#include <linux/integrity.h>
  82#include <linux/proc_ns.h>
  83
  84#include <asm/io.h>
  85#include <asm/bugs.h>
  86#include <asm/setup.h>
  87#include <asm/sections.h>
  88#include <asm/cacheflush.h>
  89
  90#ifdef CONFIG_X86_LOCAL_APIC
  91#include <asm/smp.h>
  92#endif
  93
  94static int kernel_init(void *);
  95
  96extern void init_IRQ(void);
  97extern void fork_init(unsigned long);
  98extern void radix_tree_init(void);
  99#ifndef CONFIG_DEBUG_RODATA
 100static inline void mark_rodata_ro(void) { }
 101#endif
 102
 103/*
 104 * Debug helper: via this flag we know that we are in 'early bootup code'
 105 * where only the boot processor is running with IRQ disabled.  This means
 106 * two things - IRQ must not be enabled before the flag is cleared and some
 107 * operations which are not allowed with IRQ disabled are allowed while the
 108 * flag is set.
 109 */
 110bool early_boot_irqs_disabled __read_mostly;
 111
 112enum system_states system_state __read_mostly;
 113EXPORT_SYMBOL(system_state);
 114
 115/*
 116 * Boot command-line arguments
 117 */
 118#define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 119#define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 120
 121extern void time_init(void);
 122/* Default late time init is NULL. archs can override this later. */
 123void (*__initdata late_time_init)(void);
 124
 125/* Untouched command line saved by arch-specific code. */
 126char __initdata boot_command_line[COMMAND_LINE_SIZE];
 127/* Untouched saved command line (eg. for /proc) */
 128char *saved_command_line;
 129/* Command line for parameter parsing */
 130static char *static_command_line;
 131/* Command line for per-initcall parameter parsing */
 132static char *initcall_command_line;
 133
 134static char *execute_command;
 135static char *ramdisk_execute_command;
 136
 137/*
 138 * Used to generate warnings if static_key manipulation functions are used
 139 * before jump_label_init is called.
 140 */
 141bool static_key_initialized __read_mostly;
 142EXPORT_SYMBOL_GPL(static_key_initialized);
 143
 144/*
 145 * If set, this is an indication to the drivers that reset the underlying
 146 * device before going ahead with the initialization otherwise driver might
 147 * rely on the BIOS and skip the reset operation.
 148 *
 149 * This is useful if kernel is booting in an unreliable environment.
 150 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 151 * skipped and devices will be in unknown state.
 152 */
 153unsigned int reset_devices;
 154EXPORT_SYMBOL(reset_devices);
 155
 156static int __init set_reset_devices(char *str)
 157{
 158        reset_devices = 1;
 159        return 1;
 160}
 161
 162__setup("reset_devices", set_reset_devices);
 163
 164static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 165const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 166static const char *panic_later, *panic_param;
 167
 168extern const struct obs_kernel_param __setup_start[], __setup_end[];
 169
 170static int __init obsolete_checksetup(char *line)
 171{
 172        const struct obs_kernel_param *p;
 173        int had_early_param = 0;
 174
 175        p = __setup_start;
 176        do {
 177                int n = strlen(p->str);
 178                if (parameqn(line, p->str, n)) {
 179                        if (p->early) {
 180                                /* Already done in parse_early_param?
 181                                 * (Needs exact match on param part).
 182                                 * Keep iterating, as we can have early
 183                                 * params and __setups of same names 8( */
 184                                if (line[n] == '\0' || line[n] == '=')
 185                                        had_early_param = 1;
 186                        } else if (!p->setup_func) {
 187                                pr_warn("Parameter %s is obsolete, ignored\n",
 188                                        p->str);
 189                                return 1;
 190                        } else if (p->setup_func(line + n))
 191                                return 1;
 192                }
 193                p++;
 194        } while (p < __setup_end);
 195
 196        return had_early_param;
 197}
 198
 199/*
 200 * This should be approx 2 Bo*oMips to start (note initial shift), and will
 201 * still work even if initially too large, it will just take slightly longer
 202 */
 203unsigned long loops_per_jiffy = (1<<12);
 204EXPORT_SYMBOL(loops_per_jiffy);
 205
 206static int __init debug_kernel(char *str)
 207{
 208        console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 209        return 0;
 210}
 211
 212static int __init quiet_kernel(char *str)
 213{
 214        console_loglevel = CONSOLE_LOGLEVEL_QUIET;
 215        return 0;
 216}
 217
 218early_param("debug", debug_kernel);
 219early_param("quiet", quiet_kernel);
 220
 221static int __init loglevel(char *str)
 222{
 223        int newlevel;
 224
 225        /*
 226         * Only update loglevel value when a correct setting was passed,
 227         * to prevent blind crashes (when loglevel being set to 0) that
 228         * are quite hard to debug
 229         */
 230        if (get_option(&str, &newlevel)) {
 231                console_loglevel = newlevel;
 232                return 0;
 233        }
 234
 235        return -EINVAL;
 236}
 237
 238early_param("loglevel", loglevel);
 239
 240/* Change NUL term back to "=", to make "param" the whole string. */
 241static int __init repair_env_string(char *param, char *val, const char *unused)
 242{
 243        if (val) {
 244                /* param=val or param="val"? */
 245                if (val == param+strlen(param)+1)
 246                        val[-1] = '=';
 247                else if (val == param+strlen(param)+2) {
 248                        val[-2] = '=';
 249                        memmove(val-1, val, strlen(val)+1);
 250                        val--;
 251                } else
 252                        BUG();
 253        }
 254        return 0;
 255}
 256
 257/* Anything after -- gets handed straight to init. */
 258static int __init set_init_arg(char *param, char *val, const char *unused)
 259{
 260        unsigned int i;
 261
 262        if (panic_later)
 263                return 0;
 264
 265        repair_env_string(param, val, unused);
 266
 267        for (i = 0; argv_init[i]; i++) {
 268                if (i == MAX_INIT_ARGS) {
 269                        panic_later = "init";
 270                        panic_param = param;
 271                        return 0;
 272                }
 273        }
 274        argv_init[i] = param;
 275        return 0;
 276}
 277
 278/*
 279 * Unknown boot options get handed to init, unless they look like
 280 * unused parameters (modprobe will find them in /proc/cmdline).
 281 */
 282static int __init unknown_bootoption(char *param, char *val, const char *unused)
 283{
 284        repair_env_string(param, val, unused);
 285
 286        /* Handle obsolete-style parameters */
 287        if (obsolete_checksetup(param))
 288                return 0;
 289
 290        /* Unused module parameter. */
 291        if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 292                return 0;
 293
 294        if (panic_later)
 295                return 0;
 296
 297        if (val) {
 298                /* Environment option */
 299                unsigned int i;
 300                for (i = 0; envp_init[i]; i++) {
 301                        if (i == MAX_INIT_ENVS) {
 302                                panic_later = "env";
 303                                panic_param = param;
 304                        }
 305                        if (!strncmp(param, envp_init[i], val - param))
 306                                break;
 307                }
 308                envp_init[i] = param;
 309        } else {
 310                /* Command line option */
 311                unsigned int i;
 312                for (i = 0; argv_init[i]; i++) {
 313                        if (i == MAX_INIT_ARGS) {
 314                                panic_later = "init";
 315                                panic_param = param;
 316                        }
 317                }
 318                argv_init[i] = param;
 319        }
 320        return 0;
 321}
 322
 323static int __init init_setup(char *str)
 324{
 325        unsigned int i;
 326
 327        execute_command = str;
 328        /*
 329         * In case LILO is going to boot us with default command line,
 330         * it prepends "auto" before the whole cmdline which makes
 331         * the shell think it should execute a script with such name.
 332         * So we ignore all arguments entered _before_ init=... [MJ]
 333         */
 334        for (i = 1; i < MAX_INIT_ARGS; i++)
 335                argv_init[i] = NULL;
 336        return 1;
 337}
 338__setup("init=", init_setup);
 339
 340static int __init rdinit_setup(char *str)
 341{
 342        unsigned int i;
 343
 344        ramdisk_execute_command = str;
 345        /* See "auto" comment in init_setup */
 346        for (i = 1; i < MAX_INIT_ARGS; i++)
 347                argv_init[i] = NULL;
 348        return 1;
 349}
 350__setup("rdinit=", rdinit_setup);
 351
 352#ifndef CONFIG_SMP
 353static const unsigned int setup_max_cpus = NR_CPUS;
 354#ifdef CONFIG_X86_LOCAL_APIC
 355static void __init smp_init(void)
 356{
 357        APIC_init_uniprocessor();
 358}
 359#else
 360#define smp_init()      do { } while (0)
 361#endif
 362
 363static inline void setup_nr_cpu_ids(void) { }
 364static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 365#endif
 366
 367/*
 368 * We need to store the untouched command line for future reference.
 369 * We also need to store the touched command line since the parameter
 370 * parsing is performed in place, and we should allow a component to
 371 * store reference of name/value for future reference.
 372 */
 373static void __init setup_command_line(char *command_line)
 374{
 375        saved_command_line =
 376                memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 377        initcall_command_line =
 378                memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
 379        static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
 380        strcpy(saved_command_line, boot_command_line);
 381        strcpy(static_command_line, command_line);
 382}
 383
 384/*
 385 * We need to finalize in a non-__init function or else race conditions
 386 * between the root thread and the init thread may cause start_kernel to
 387 * be reaped by free_initmem before the root thread has proceeded to
 388 * cpu_idle.
 389 *
 390 * gcc-3.4 accidentally inlines this function, so use noinline.
 391 */
 392
 393static __initdata DECLARE_COMPLETION(kthreadd_done);
 394
 395static noinline void __init_refok rest_init(void)
 396{
 397        int pid;
 398
 399        rcu_scheduler_starting();
 400        /*
 401         * We need to spawn init first so that it obtains pid 1, however
 402         * the init task will end up wanting to create kthreads, which, if
 403         * we schedule it before we create kthreadd, will OOPS.
 404         */
 405        kernel_thread(kernel_init, NULL, CLONE_FS);
 406        numa_default_policy();
 407        pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 408        rcu_read_lock();
 409        kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 410        rcu_read_unlock();
 411        complete(&kthreadd_done);
 412
 413        /*
 414         * The boot idle thread must execute schedule()
 415         * at least once to get things moving:
 416         */
 417        init_idle_bootup_task(current);
 418        schedule_preempt_disabled();
 419        /* Call into cpu_idle with preempt disabled */
 420        cpu_startup_entry(CPUHP_ONLINE);
 421}
 422
 423/* Check for early params. */
 424static int __init do_early_param(char *param, char *val, const char *unused)
 425{
 426        const struct obs_kernel_param *p;
 427
 428        for (p = __setup_start; p < __setup_end; p++) {
 429                if ((p->early && parameq(param, p->str)) ||
 430                    (strcmp(param, "console") == 0 &&
 431                     strcmp(p->str, "earlycon") == 0)
 432                ) {
 433                        if (p->setup_func(val) != 0)
 434                                pr_warn("Malformed early option '%s'\n", param);
 435                }
 436        }
 437        /* We accept everything at this stage. */
 438        return 0;
 439}
 440
 441void __init parse_early_options(char *cmdline)
 442{
 443        parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 444}
 445
 446/* Arch code calls this early on, or if not, just before other parsing. */
 447void __init parse_early_param(void)
 448{
 449        static int done __initdata;
 450        static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 451
 452        if (done)
 453                return;
 454
 455        /* All fall through to do_early_param. */
 456        strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 457        parse_early_options(tmp_cmdline);
 458        done = 1;
 459}
 460
 461/*
 462 *      Activate the first processor.
 463 */
 464
 465static void __init boot_cpu_init(void)
 466{
 467        int cpu = smp_processor_id();
 468        /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 469        set_cpu_online(cpu, true);
 470        set_cpu_active(cpu, true);
 471        set_cpu_present(cpu, true);
 472        set_cpu_possible(cpu, true);
 473}
 474
 475void __init __weak smp_setup_processor_id(void)
 476{
 477}
 478
 479# if THREAD_SIZE >= PAGE_SIZE
 480void __init __weak thread_info_cache_init(void)
 481{
 482}
 483#endif
 484
 485/*
 486 * Set up kernel memory allocators
 487 */
 488static void __init mm_init(void)
 489{
 490        /*
 491         * page_ext requires contiguous pages,
 492         * bigger than MAX_ORDER unless SPARSEMEM.
 493         */
 494        page_ext_init_flatmem();
 495        mem_init();
 496        kmem_cache_init();
 497        percpu_init_late();
 498        pgtable_init();
 499        vmalloc_init();
 500}
 501
 502asmlinkage __visible void __init start_kernel(void)
 503{
 504        char *command_line;
 505        char *after_dashes;
 506
 507        /*
 508         * Need to run as early as possible, to initialize the
 509         * lockdep hash:
 510         */
 511        lockdep_init();
 512        set_task_stack_end_magic(&init_task);
 513        smp_setup_processor_id();
 514        debug_objects_early_init();
 515
 516        /*
 517         * Set up the the initial canary ASAP:
 518         */
 519        boot_init_stack_canary();
 520
 521        cgroup_init_early();
 522
 523        local_irq_disable();
 524        early_boot_irqs_disabled = true;
 525
 526/*
 527 * Interrupts are still disabled. Do necessary setups, then
 528 * enable them
 529 */
 530        boot_cpu_init();
 531        page_address_init();
 532        pr_notice("%s", linux_banner);
 533        setup_arch(&command_line);
 534        mm_init_cpumask(&init_mm);
 535        setup_command_line(command_line);
 536        setup_nr_cpu_ids();
 537        setup_per_cpu_areas();
 538        smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 539
 540        build_all_zonelists(NULL, NULL);
 541        page_alloc_init();
 542
 543        pr_notice("Kernel command line: %s\n", boot_command_line);
 544        parse_early_param();
 545        after_dashes = parse_args("Booting kernel",
 546                                  static_command_line, __start___param,
 547                                  __stop___param - __start___param,
 548                                  -1, -1, &unknown_bootoption);
 549        if (!IS_ERR_OR_NULL(after_dashes))
 550                parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
 551                           set_init_arg);
 552
 553        jump_label_init();
 554
 555        /*
 556         * These use large bootmem allocations and must precede
 557         * kmem_cache_init()
 558         */
 559        setup_log_buf(0);
 560        pidhash_init();
 561        vfs_caches_init_early();
 562        sort_main_extable();
 563        trap_init();
 564        mm_init();
 565
 566        /*
 567         * Set up the scheduler prior starting any interrupts (such as the
 568         * timer interrupt). Full topology setup happens at smp_init()
 569         * time - but meanwhile we still have a functioning scheduler.
 570         */
 571        sched_init();
 572        /*
 573         * Disable preemption - early bootup scheduling is extremely
 574         * fragile until we cpu_idle() for the first time.
 575         */
 576        preempt_disable();
 577        if (WARN(!irqs_disabled(),
 578                 "Interrupts were enabled *very* early, fixing it\n"))
 579                local_irq_disable();
 580        idr_init_cache();
 581        rcu_init();
 582
 583        /* trace_printk() and trace points may be used after this */
 584        trace_init();
 585
 586        context_tracking_init();
 587        radix_tree_init();
 588        /* init some links before init_ISA_irqs() */
 589        early_irq_init();
 590        init_IRQ();
 591        tick_init();
 592        rcu_init_nohz();
 593        init_timers();
 594        hrtimers_init();
 595        softirq_init();
 596        timekeeping_init();
 597        time_init();
 598        sched_clock_postinit();
 599        perf_event_init();
 600        profile_init();
 601        call_function_init();
 602        WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 603        early_boot_irqs_disabled = false;
 604        local_irq_enable();
 605
 606        kmem_cache_init_late();
 607
 608        /*
 609         * HACK ALERT! This is early. We're enabling the console before
 610         * we've done PCI setups etc, and console_init() must be aware of
 611         * this. But we do want output early, in case something goes wrong.
 612         */
 613        console_init();
 614        if (panic_later)
 615                panic("Too many boot %s vars at `%s'", panic_later,
 616                      panic_param);
 617
 618        lockdep_info();
 619
 620        /*
 621         * Need to run this when irqs are enabled, because it wants
 622         * to self-test [hard/soft]-irqs on/off lock inversion bugs
 623         * too:
 624         */
 625        locking_selftest();
 626
 627#ifdef CONFIG_BLK_DEV_INITRD
 628        if (initrd_start && !initrd_below_start_ok &&
 629            page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 630                pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 631                    page_to_pfn(virt_to_page((void *)initrd_start)),
 632                    min_low_pfn);
 633                initrd_start = 0;
 634        }
 635#endif
 636        page_ext_init();
 637        debug_objects_mem_init();
 638        kmemleak_init();
 639        setup_per_cpu_pageset();
 640        numa_policy_init();
 641        if (late_time_init)
 642                late_time_init();
 643        sched_clock_init();
 644        calibrate_delay();
 645        pidmap_init();
 646        anon_vma_init();
 647        acpi_early_init();
 648#ifdef CONFIG_X86
 649        if (efi_enabled(EFI_RUNTIME_SERVICES))
 650                efi_enter_virtual_mode();
 651#endif
 652#ifdef CONFIG_X86_ESPFIX64
 653        /* Should be run before the first non-init thread is created */
 654        init_espfix_bsp();
 655#endif
 656        thread_info_cache_init();
 657        cred_init();
 658        fork_init(totalram_pages);
 659        proc_caches_init();
 660        buffer_init();
 661        key_init();
 662        security_init();
 663        dbg_late_init();
 664        vfs_caches_init(totalram_pages);
 665        signals_init();
 666        /* rootfs populating might need page-writeback */
 667        page_writeback_init();
 668        proc_root_init();
 669        nsfs_init();
 670        cgroup_init();
 671        cpuset_init();
 672        taskstats_init_early();
 673        delayacct_init();
 674
 675        check_bugs();
 676
 677        sfi_init_late();
 678
 679        if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 680                efi_late_init();
 681                efi_free_boot_services();
 682        }
 683
 684        ftrace_init();
 685
 686        /* Do the rest non-__init'ed, we're now alive */
 687        rest_init();
 688}
 689
 690/* Call all constructor functions linked into the kernel. */
 691static void __init do_ctors(void)
 692{
 693#ifdef CONFIG_CONSTRUCTORS
 694        ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 695
 696        for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 697                (*fn)();
 698#endif
 699}
 700
 701bool initcall_debug;
 702core_param(initcall_debug, initcall_debug, bool, 0644);
 703
 704#ifdef CONFIG_KALLSYMS
 705struct blacklist_entry {
 706        struct list_head next;
 707        char *buf;
 708};
 709
 710static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
 711
 712static int __init initcall_blacklist(char *str)
 713{
 714        char *str_entry;
 715        struct blacklist_entry *entry;
 716
 717        /* str argument is a comma-separated list of functions */
 718        do {
 719                str_entry = strsep(&str, ",");
 720                if (str_entry) {
 721                        pr_debug("blacklisting initcall %s\n", str_entry);
 722                        entry = alloc_bootmem(sizeof(*entry));
 723                        entry->buf = alloc_bootmem(strlen(str_entry) + 1);
 724                        strcpy(entry->buf, str_entry);
 725                        list_add(&entry->next, &blacklisted_initcalls);
 726                }
 727        } while (str_entry);
 728
 729        return 0;
 730}
 731
 732static bool __init_or_module initcall_blacklisted(initcall_t fn)
 733{
 734        struct list_head *tmp;
 735        struct blacklist_entry *entry;
 736        char *fn_name;
 737
 738        fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
 739        if (!fn_name)
 740                return false;
 741
 742        list_for_each(tmp, &blacklisted_initcalls) {
 743                entry = list_entry(tmp, struct blacklist_entry, next);
 744                if (!strcmp(fn_name, entry->buf)) {
 745                        pr_debug("initcall %s blacklisted\n", fn_name);
 746                        kfree(fn_name);
 747                        return true;
 748                }
 749        }
 750
 751        kfree(fn_name);
 752        return false;
 753}
 754#else
 755static int __init initcall_blacklist(char *str)
 756{
 757        pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
 758        return 0;
 759}
 760
 761static bool __init_or_module initcall_blacklisted(initcall_t fn)
 762{
 763        return false;
 764}
 765#endif
 766__setup("initcall_blacklist=", initcall_blacklist);
 767
 768static int __init_or_module do_one_initcall_debug(initcall_t fn)
 769{
 770        ktime_t calltime, delta, rettime;
 771        unsigned long long duration;
 772        int ret;
 773
 774        printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 775        calltime = ktime_get();
 776        ret = fn();
 777        rettime = ktime_get();
 778        delta = ktime_sub(rettime, calltime);
 779        duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 780        printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 781                 fn, ret, duration);
 782
 783        return ret;
 784}
 785
 786int __init_or_module do_one_initcall(initcall_t fn)
 787{
 788        int count = preempt_count();
 789        int ret;
 790        char msgbuf[64];
 791
 792        if (initcall_blacklisted(fn))
 793                return -EPERM;
 794
 795        if (initcall_debug)
 796                ret = do_one_initcall_debug(fn);
 797        else
 798                ret = fn();
 799
 800        msgbuf[0] = 0;
 801
 802        if (preempt_count() != count) {
 803                sprintf(msgbuf, "preemption imbalance ");
 804                preempt_count_set(count);
 805        }
 806        if (irqs_disabled()) {
 807                strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 808                local_irq_enable();
 809        }
 810        WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 811
 812        return ret;
 813}
 814
 815
 816extern initcall_t __initcall_start[];
 817extern initcall_t __initcall0_start[];
 818extern initcall_t __initcall1_start[];
 819extern initcall_t __initcall2_start[];
 820extern initcall_t __initcall3_start[];
 821extern initcall_t __initcall4_start[];
 822extern initcall_t __initcall5_start[];
 823extern initcall_t __initcall6_start[];
 824extern initcall_t __initcall7_start[];
 825extern initcall_t __initcall_end[];
 826
 827static initcall_t *initcall_levels[] __initdata = {
 828        __initcall0_start,
 829        __initcall1_start,
 830        __initcall2_start,
 831        __initcall3_start,
 832        __initcall4_start,
 833        __initcall5_start,
 834        __initcall6_start,
 835        __initcall7_start,
 836        __initcall_end,
 837};
 838
 839/* Keep these in sync with initcalls in include/linux/init.h */
 840static char *initcall_level_names[] __initdata = {
 841        "early",
 842        "core",
 843        "postcore",
 844        "arch",
 845        "subsys",
 846        "fs",
 847        "device",
 848        "late",
 849};
 850
 851static void __init do_initcall_level(int level)
 852{
 853        initcall_t *fn;
 854
 855        strcpy(initcall_command_line, saved_command_line);
 856        parse_args(initcall_level_names[level],
 857                   initcall_command_line, __start___param,
 858                   __stop___param - __start___param,
 859                   level, level,
 860                   &repair_env_string);
 861
 862        for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 863                do_one_initcall(*fn);
 864}
 865
 866static void __init do_initcalls(void)
 867{
 868        int level;
 869
 870        for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 871                do_initcall_level(level);
 872}
 873
 874/*
 875 * Ok, the machine is now initialized. None of the devices
 876 * have been touched yet, but the CPU subsystem is up and
 877 * running, and memory and process management works.
 878 *
 879 * Now we can finally start doing some real work..
 880 */
 881static void __init do_basic_setup(void)
 882{
 883        cpuset_init_smp();
 884        usermodehelper_init();
 885        shmem_init();
 886        driver_init();
 887        init_irq_proc();
 888        do_ctors();
 889        usermodehelper_enable();
 890        do_initcalls();
 891        random_int_secret_init();
 892}
 893
 894static void __init do_pre_smp_initcalls(void)
 895{
 896        initcall_t *fn;
 897
 898        for (fn = __initcall_start; fn < __initcall0_start; fn++)
 899                do_one_initcall(*fn);
 900}
 901
 902/*
 903 * This function requests modules which should be loaded by default and is
 904 * called twice right after initrd is mounted and right before init is
 905 * exec'd.  If such modules are on either initrd or rootfs, they will be
 906 * loaded before control is passed to userland.
 907 */
 908void __init load_default_modules(void)
 909{
 910        load_default_elevator_module();
 911}
 912
 913static int run_init_process(const char *init_filename)
 914{
 915        argv_init[0] = init_filename;
 916        return do_execve(getname_kernel(init_filename),
 917                (const char __user *const __user *)argv_init,
 918                (const char __user *const __user *)envp_init);
 919}
 920
 921static int try_to_run_init_process(const char *init_filename)
 922{
 923        int ret;
 924
 925        ret = run_init_process(init_filename);
 926
 927        if (ret && ret != -ENOENT) {
 928                pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
 929                       init_filename, ret);
 930        }
 931
 932        return ret;
 933}
 934
 935static noinline void __init kernel_init_freeable(void);
 936
 937static int __ref kernel_init(void *unused)
 938{
 939        int ret;
 940
 941        kernel_init_freeable();
 942        /* need to finish all async __init code before freeing the memory */
 943        async_synchronize_full();
 944        free_initmem();
 945        mark_rodata_ro();
 946        system_state = SYSTEM_RUNNING;
 947        numa_default_policy();
 948
 949        flush_delayed_fput();
 950
 951        if (ramdisk_execute_command) {
 952                ret = run_init_process(ramdisk_execute_command);
 953                if (!ret)
 954                        return 0;
 955                pr_err("Failed to execute %s (error %d)\n",
 956                       ramdisk_execute_command, ret);
 957        }
 958
 959        /*
 960         * We try each of these until one succeeds.
 961         *
 962         * The Bourne shell can be used instead of init if we are
 963         * trying to recover a really broken machine.
 964         */
 965        if (execute_command) {
 966                ret = run_init_process(execute_command);
 967                if (!ret)
 968                        return 0;
 969#ifndef CONFIG_INIT_FALLBACK
 970                panic("Requested init %s failed (error %d).",
 971                      execute_command, ret);
 972#else
 973                pr_err("Failed to execute %s (error %d).  Attempting defaults...\n",
 974                       execute_command, ret);
 975#endif
 976        }
 977        if (!try_to_run_init_process("/sbin/init") ||
 978            !try_to_run_init_process("/etc/init") ||
 979            !try_to_run_init_process("/bin/init") ||
 980            !try_to_run_init_process("/bin/sh"))
 981                return 0;
 982
 983        panic("No working init found.  Try passing init= option to kernel. "
 984              "See Linux Documentation/init.txt for guidance.");
 985}
 986
 987static noinline void __init kernel_init_freeable(void)
 988{
 989        /*
 990         * Wait until kthreadd is all set-up.
 991         */
 992        wait_for_completion(&kthreadd_done);
 993
 994        /* Now the scheduler is fully set up and can do blocking allocations */
 995        gfp_allowed_mask = __GFP_BITS_MASK;
 996
 997        /*
 998         * init can allocate pages on any node
 999         */
1000        set_mems_allowed(node_states[N_MEMORY]);
1001        /*
1002         * init can run on any cpu.
1003         */
1004        set_cpus_allowed_ptr(current, cpu_all_mask);
1005
1006        cad_pid = task_pid(current);
1007
1008        smp_prepare_cpus(setup_max_cpus);
1009
1010        do_pre_smp_initcalls();
1011        lockup_detector_init();
1012
1013        smp_init();
1014        sched_init_smp();
1015
1016        do_basic_setup();
1017
1018        /* Open the /dev/console on the rootfs, this should never fail */
1019        if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1020                pr_err("Warning: unable to open an initial console.\n");
1021
1022        (void) sys_dup(0);
1023        (void) sys_dup(0);
1024        /*
1025         * check if there is an early userspace init.  If yes, let it do all
1026         * the work
1027         */
1028
1029        if (!ramdisk_execute_command)
1030                ramdisk_execute_command = "/init";
1031
1032        if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1033                ramdisk_execute_command = NULL;
1034                prepare_namespace();
1035        }
1036
1037        /*
1038         * Ok, we have completed the initial bootup, and
1039         * we're essentially up and running. Get rid of the
1040         * initmem segments and start the user-mode stuff..
1041         *
1042         * rootfs is available now, try loading the public keys
1043         * and default modules
1044         */
1045
1046        integrity_load_keys();
1047        load_default_modules();
1048}
1049
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