init/main.c

   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_cgroup.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
  81 #include <asm/io.h>
  82 #include <asm/bugs.h>
  83 #include <asm/setup.h>
  84 #include <asm/sections.h>
  85 #include <asm/cacheflush.h>
  86
  87 #ifdef CONFIG_X86_LOCAL_APIC
  88 #include <asm/smp.h>
  89 #endif
  90
  91 static int kernel_init(void *);
  92
  93 extern void init_IRQ(void);
  94 extern void fork_init(unsigned long);
  95 extern void mca_init(void);
  96 extern void sbus_init(void);
  97 extern void radix_tree_init(void);
  98 #ifndef CONFIG_DEBUG_RODATA
  99 static inline void mark_rodata_ro(void) { }
 100 #endif
 101
 102 #ifdef CONFIG_TC
 103 extern void tc_init(void);
 104 #endif
 105
 106 /*
 107  * Debug helper: via this flag we know that we are in 'early bootup code'
 108  * where only the boot processor is running with IRQ disabled.  This means
 109  * two things - IRQ must not be enabled before the flag is cleared and some
 110  * operations which are not allowed with IRQ disabled are allowed while the
 111  * flag is set.
 112  */
 113 bool early_boot_irqs_disabled __read_mostly;
 114
 115 enum system_states system_state __read_mostly;
 116 EXPORT_SYMBOL(system_state);
 117
 118 /*
 119  * Boot command-line arguments
 120  */
 121 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 122 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 123
 124 extern void time_init(void);
 125 /* Default late time init is NULL. archs can override this later. */
 126 void (*__initdata late_time_init)(void);
 127 extern void softirq_init(void);
 128
 129 /* Untouched command line saved by arch-specific code. */
 130 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 131 /* Untouched saved command line (eg. for /proc) */
 132 char *saved_command_line;
 133 /* Command line for parameter parsing */
 134 static char *static_command_line;
 135
 136 static char *execute_command;
 137 static char *ramdisk_execute_command;
 138
 139 /*
 140  * If set, this is an indication to the drivers that reset the underlying
 141  * device before going ahead with the initialization otherwise driver might
 142  * rely on the BIOS and skip the reset operation.
 143  *
 144  * This is useful if kernel is booting in an unreliable environment.
 145  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 146  * skipped and devices will be in unknown state.
 147  */
 148 unsigned int reset_devices;
 149 EXPORT_SYMBOL(reset_devices);
 150
 151 static int __init set_reset_devices(char *str)
 152 {
 153         reset_devices = 1;
 154         return 1;
 155 }
 156
 157 __setup("reset_devices", set_reset_devices);
 158
 159 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 160 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 161 static const char *panic_later, *panic_param;
 162
 163 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 164
 165 static int __init obsolete_checksetup(char *line)
 166 {
 167         const struct obs_kernel_param *p;
 168         int had_early_param = 0;
 169
 170         p = __setup_start;
 171         do {
 172                 int n = strlen(p->str);
 173                 if (parameqn(line, p->str, n)) {
 174                         if (p->early) {
 175                                 /* Already done in parse_early_param?
 176                                  * (Needs exact match on param part).
 177                                  * Keep iterating, as we can have early
 178                                  * params and __setups of same names 8( */
 179                                 if (line[n] == '\0' || line[n] == '=')
 180                                         had_early_param = 1;
 181                         } else if (!p->setup_func) {
 182                                 pr_warn("Parameter %s is obsolete, ignored\n",
 183                                         p->str);
 184                                 return 1;
 185                         } else if (p->setup_func(line + n))
 186                                 return 1;
 187                 }
 188                 p++;
 189         } while (p < __setup_end);
 190
 191         return had_early_param;
 192 }
 193
 194 /*
 195  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 196  * still work even if initially too large, it will just take slightly longer
 197  */
 198 unsigned long loops_per_jiffy = (1<<12);
 199
 200 EXPORT_SYMBOL(loops_per_jiffy);
 201
 202 static int __init debug_kernel(char *str)
 203 {
 204         console_loglevel = 10;
 205         return 0;
 206 }
 207
 208 static int __init quiet_kernel(char *str)
 209 {
 210         console_loglevel = 4;
 211         return 0;
 212 }
 213
 214 early_param("debug", debug_kernel);
 215 early_param("quiet", quiet_kernel);
 216
 217 static int __init loglevel(char *str)
 218 {
 219         int newlevel;
 220
 221         /*
 222          * Only update loglevel value when a correct setting was passed,
 223          * to prevent blind crashes (when loglevel being set to 0) that
 224          * are quite hard to debug
 225          */
 226         if (get_option(&str, &newlevel)) {
 227                 console_loglevel = newlevel;
 228                 return 0;
 229         }
 230
 231         return -EINVAL;
 232 }
 233
 234 early_param("loglevel", loglevel);
 235
 236 /* Change NUL term back to "=", to make "param" the whole string. */
 237 static int __init repair_env_string(char *param, char *val, const char *unused)
 238 {
 239         if (val) {
 240                 /* param=val or param="val"? */
 241                 if (val == param+strlen(param)+1)
 242                         val[-1] = '=';
 243                 else if (val == param+strlen(param)+2) {
 244                         val[-2] = '=';
 245                         memmove(val-1, val, strlen(val)+1);
 246                         val--;
 247                 } else
 248                         BUG();
 249         }
 250         return 0;
 251 }
 252
 253 /*
 254  * Unknown boot options get handed to init, unless they look like
 255  * unused parameters (modprobe will find them in /proc/cmdline).
 256  */
 257 static int __init unknown_bootoption(char *param, char *val, const char *unused)
 258 {
 259         repair_env_string(param, val, unused);
 260
 261         /* Handle obsolete-style parameters */
 262         if (obsolete_checksetup(param))
 263                 return 0;
 264
 265         /* Unused module parameter. */
 266         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 267                 return 0;
 268
 269         if (panic_later)
 270                 return 0;
 271
 272         if (val) {
 273                 /* Environment option */
 274                 unsigned int i;
 275                 for (i = 0; envp_init[i]; i++) {
 276                         if (i == MAX_INIT_ENVS) {
 277                                 panic_later = "Too many boot env vars at `%s'";
 278                                 panic_param = param;
 279                         }
 280                         if (!strncmp(param, envp_init[i], val - param))
 281                                 break;
 282                 }
 283                 envp_init[i] = param;
 284         } else {
 285                 /* Command line option */
 286                 unsigned int i;
 287                 for (i = 0; argv_init[i]; i++) {
 288                         if (i == MAX_INIT_ARGS) {
 289                                 panic_later = "Too many boot init vars at `%s'";
 290                                 panic_param = param;
 291                         }
 292                 }
 293                 argv_init[i] = param;
 294         }
 295         return 0;
 296 }
 297
 298 static int __init init_setup(char *str)
 299 {
 300         unsigned int i;
 301
 302         execute_command = str;
 303         /*
 304          * In case LILO is going to boot us with default command line,
 305          * it prepends "auto" before the whole cmdline which makes
 306          * the shell think it should execute a script with such name.
 307          * So we ignore all arguments entered _before_ init=... [MJ]
 308          */
 309         for (i = 1; i < MAX_INIT_ARGS; i++)
 310                 argv_init[i] = NULL;
 311         return 1;
 312 }
 313 __setup("init=", init_setup);
 314
 315 static int __init rdinit_setup(char *str)
 316 {
 317         unsigned int i;
 318
 319         ramdisk_execute_command = str;
 320         /* See "auto" comment in init_setup */
 321         for (i = 1; i < MAX_INIT_ARGS; i++)
 322                 argv_init[i] = NULL;
 323         return 1;
 324 }
 325 __setup("rdinit=", rdinit_setup);
 326
 327 #ifndef CONFIG_SMP
 328 static const unsigned int setup_max_cpus = NR_CPUS;
 329 #ifdef CONFIG_X86_LOCAL_APIC
 330 static void __init smp_init(void)
 331 {
 332         APIC_init_uniprocessor();
 333 }
 334 #else
 335 #define smp_init()      do { } while (0)
 336 #endif
 337
 338 static inline void setup_nr_cpu_ids(void) { }
 339 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 340 #endif
 341
 342 /*
 343  * We need to store the untouched command line for future reference.
 344  * We also need to store the touched command line since the parameter
 345  * parsing is performed in place, and we should allow a component to
 346  * store reference of name/value for future reference.
 347  */
 348 static void __init setup_command_line(char *command_line)
 349 {
 350         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 351         static_command_line = alloc_bootmem(strlen (command_line)+1);
 352         strcpy (saved_command_line, boot_command_line);
 353         strcpy (static_command_line, command_line);
 354 }
 355
 356 /*
 357  * We need to finalize in a non-__init function or else race conditions
 358  * between the root thread and the init thread may cause start_kernel to
 359  * be reaped by free_initmem before the root thread has proceeded to
 360  * cpu_idle.
 361  *
 362  * gcc-3.4 accidentally inlines this function, so use noinline.
 363  */
 364
 365 static __initdata DECLARE_COMPLETION(kthreadd_done);
 366
 367 static noinline void __init_refok rest_init(void)
 368 {
 369         int pid;
 370
 371         rcu_scheduler_starting();
 372         /*
 373          * We need to spawn init first so that it obtains pid 1, however
 374          * the init task will end up wanting to create kthreads, which, if
 375          * we schedule it before we create kthreadd, will OOPS.
 376          */
 377         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 378         numa_default_policy();
 379         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 380         rcu_read_lock();
 381         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 382         rcu_read_unlock();
 383         complete(&kthreadd_done);
 384
 385         /*
 386          * The boot idle thread must execute schedule()
 387          * at least once to get things moving:
 388          */
 389         init_idle_bootup_task(current);
 390         schedule_preempt_disabled();
 391         /* Call into cpu_idle with preempt disabled */
 392         cpu_startup_entry(CPUHP_ONLINE);
 393 }
 394
 395 /* Check for early params. */
 396 static int __init do_early_param(char *param, char *val, const char *unused)
 397 {
 398         const struct obs_kernel_param *p;
 399
 400         for (p = __setup_start; p < __setup_end; p++) {
 401                 if ((p->early && parameq(param, p->str)) ||
 402                     (strcmp(param, "console") == 0 &&
 403                      strcmp(p->str, "earlycon") == 0)
 404                 ) {
 405                         if (p->setup_func(val) != 0)
 406                                 pr_warn("Malformed early option '%s'\n", param);
 407                 }
 408         }
 409         /* We accept everything at this stage. */
 410         return 0;
 411 }
 412
 413 void __init parse_early_options(char *cmdline)
 414 {
 415         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 416 }
 417
 418 /* Arch code calls this early on, or if not, just before other parsing. */
 419 void __init parse_early_param(void)
 420 {
 421         static __initdata int done = 0;
 422         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 423
 424         if (done)
 425                 return;
 426
 427         /* All fall through to do_early_param. */
 428         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 429         parse_early_options(tmp_cmdline);
 430         done = 1;
 431 }
 432
 433 /*
 434  *      Activate the first processor.
 435  */
 436
 437 static void __init boot_cpu_init(void)
 438 {
 439         int cpu = smp_processor_id();
 440         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 441         set_cpu_online(cpu, true);
 442         set_cpu_active(cpu, true);
 443         set_cpu_present(cpu, true);
 444         set_cpu_possible(cpu, true);
 445 }
 446
 447 void __init __weak smp_setup_processor_id(void)
 448 {
 449 }
 450
 451 # if THREAD_SIZE >= PAGE_SIZE
 452 void __init __weak thread_info_cache_init(void)
 453 {
 454 }
 455 #endif
 456
 457 /*
 458  * Set up kernel memory allocators
 459  */
 460 static void __init mm_init(void)
 461 {
 462         /*
 463          * page_cgroup requires contiguous pages,
 464          * bigger than MAX_ORDER unless SPARSEMEM.
 465          */
 466         page_cgroup_init_flatmem();
 467         mem_init();
 468         kmem_cache_init();
 469         percpu_init_late();
 470         pgtable_cache_init();
 471         vmalloc_init();
 472 }
 473
 474 asmlinkage void __init start_kernel(void)
 475 {
 476         char * command_line;
 477         extern const struct kernel_param __start___param[], __stop___param[];
 478
 479         /*
 480          * Need to run as early as possible, to initialize the
 481          * lockdep hash:
 482          */
 483         lockdep_init();
 484         smp_setup_processor_id();
 485         debug_objects_early_init();
 486
 487         /*
 488          * Set up the the initial canary ASAP:
 489          */
 490         boot_init_stack_canary();
 491
 492         cgroup_init_early();
 493
 494         local_irq_disable();
 495         early_boot_irqs_disabled = true;
 496
 497 /*
 498  * Interrupts are still disabled. Do necessary setups, then
 499  * enable them
 500  */
 501         boot_cpu_init();
 502         page_address_init();
 503         pr_notice("%s", linux_banner);
 504         setup_arch(&command_line);
 505         mm_init_owner(&init_mm, &init_task);
 506         mm_init_cpumask(&init_mm);
 507         setup_command_line(command_line);
 508         setup_nr_cpu_ids();
 509         setup_per_cpu_areas();
 510         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 511
 512         build_all_zonelists(NULL, NULL);
 513         page_alloc_init();
 514
 515         pr_notice("Kernel command line: %s\n", boot_command_line);
 516         parse_early_param();
 517         parse_args("Booting kernel", static_command_line, __start___param,
 518                    __stop___param - __start___param,
 519                    -1, -1, &unknown_bootoption);
 520
 521         jump_label_init();
 522
 523         /*
 524          * These use large bootmem allocations and must precede
 525          * kmem_cache_init()
 526          */
 527         setup_log_buf(0);
 528         pidhash_init();
 529         vfs_caches_init_early();
 530         sort_main_extable();
 531         trap_init();
 532         mm_init();
 533
 534         /*
 535          * Set up the scheduler prior starting any interrupts (such as the
 536          * timer interrupt). Full topology setup happens at smp_init()
 537          * time - but meanwhile we still have a functioning scheduler.
 538          */
 539         sched_init();
 540         /*
 541          * Disable preemption - early bootup scheduling is extremely
 542          * fragile until we cpu_idle() for the first time.
 543          */
 544         preempt_disable();
 545         if (WARN(!irqs_disabled(), "Interrupts were enabled *very* early, fixing it\n"))
 546                 local_irq_disable();
 547         idr_init_cache();
 548         rcu_init();
 549         tick_nohz_init();
 550         context_tracking_init();
 551         radix_tree_init();
 552         /* init some links before init_ISA_irqs() */
 553         early_irq_init();
 554         init_IRQ();
 555         tick_init();
 556         init_timers();
 557         hrtimers_init();
 558         softirq_init();
 559         timekeeping_init();
 560         time_init();
 561         sched_clock_postinit();
 562         perf_event_init();
 563         profile_init();
 564         call_function_init();
 565         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 566         early_boot_irqs_disabled = false;
 567         local_irq_enable();
 568
 569         kmem_cache_init_late();
 570
 571         /*
 572          * HACK ALERT! This is early. We're enabling the console before
 573          * we've done PCI setups etc, and console_init() must be aware of
 574          * this. But we do want output early, in case something goes wrong.
 575          */
 576         console_init();
 577         if (panic_later)
 578                 panic(panic_later, panic_param);
 579
 580         lockdep_info();
 581
 582         /*
 583          * Need to run this when irqs are enabled, because it wants
 584          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 585          * too:
 586          */
 587         locking_selftest();
 588
 589 #ifdef CONFIG_BLK_DEV_INITRD
 590         if (initrd_start && !initrd_below_start_ok &&
 591             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 592                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
 593                     page_to_pfn(virt_to_page((void *)initrd_start)),
 594                     min_low_pfn);
 595                 initrd_start = 0;
 596         }
 597 #endif
 598         page_cgroup_init();
 599         debug_objects_mem_init();
 600         kmemleak_init();
 601         setup_per_cpu_pageset();
 602         numa_policy_init();
 603         if (late_time_init)
 604                 late_time_init();
 605         sched_clock_init();
 606         calibrate_delay();
 607         pidmap_init();
 608         anon_vma_init();
 609 #ifdef CONFIG_X86
 610         if (efi_enabled(EFI_RUNTIME_SERVICES))
 611                 efi_enter_virtual_mode();
 612 #endif
 613 #ifdef CONFIG_X86_ESPFIX64
 614         /* Should be run before the first non-init thread is created */
 615         init_espfix_bsp();
 616 #endif
 617         thread_info_cache_init();
 618         cred_init();
 619         fork_init(totalram_pages);
 620         proc_caches_init();
 621         buffer_init();
 622         key_init();
 623         security_init();
 624         dbg_late_init();
 625         vfs_caches_init(totalram_pages);
 626         signals_init();
 627         /* rootfs populating might need page-writeback */
 628         page_writeback_init();
 629 #ifdef CONFIG_PROC_FS
 630         proc_root_init();
 631 #endif
 632         cgroup_init();
 633         cpuset_init();
 634         taskstats_init_early();
 635         delayacct_init();
 636
 637         check_bugs();
 638
 639         acpi_early_init(); /* before LAPIC and SMP init */
 640         sfi_init_late();
 641
 642         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 643                 efi_late_init();
 644                 efi_free_boot_services();
 645         }
 646
 647         ftrace_init();
 648
 649         /* Do the rest non-__init'ed, we're now alive */
 650         rest_init();
 651 }
 652
 653 /* Call all constructor functions linked into the kernel. */
 654 static void __init do_ctors(void)
 655 {
 656 #ifdef CONFIG_CONSTRUCTORS
 657         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 658
 659         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 660                 (*fn)();
 661 #endif
 662 }
 663
 664 bool initcall_debug;
 665 core_param(initcall_debug, initcall_debug, bool, 0644);
 666
 667 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 668 {
 669         ktime_t calltime, delta, rettime;
 670         unsigned long long duration;
 671         int ret;
 672
 673         pr_debug("calling  %pF @ %i\n", fn, task_pid_nr(current));
 674         calltime = ktime_get();
 675         ret = fn();
 676         rettime = ktime_get();
 677         delta = ktime_sub(rettime, calltime);
 678         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 679         pr_debug("initcall %pF returned %d after %lld usecs\n",
 680                  fn, ret, duration);
 681
 682         return ret;
 683 }
 684
 685 int __init_or_module do_one_initcall(initcall_t fn)
 686 {
 687         int count = preempt_count();
 688         int ret;
 689         char msgbuf[64];
 690
 691         if (initcall_debug)
 692                 ret = do_one_initcall_debug(fn);
 693         else
 694                 ret = fn();
 695
 696         msgbuf[0] = 0;
 697
 698         if (preempt_count() != count) {
 699                 sprintf(msgbuf, "preemption imbalance ");
 700                 preempt_count() = count;
 701         }
 702         if (irqs_disabled()) {
 703                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 704                 local_irq_enable();
 705         }
 706         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
 707
 708         return ret;
 709 }
 710
 711
 712 extern initcall_t __initcall_start[];
 713 extern initcall_t __initcall0_start[];
 714 extern initcall_t __initcall1_start[];
 715 extern initcall_t __initcall2_start[];
 716 extern initcall_t __initcall3_start[];
 717 extern initcall_t __initcall4_start[];
 718 extern initcall_t __initcall5_start[];
 719 extern initcall_t __initcall6_start[];
 720 extern initcall_t __initcall7_start[];
 721 extern initcall_t __initcall_end[];
 722
 723 static initcall_t *initcall_levels[] __initdata = {
 724         __initcall0_start,
 725         __initcall1_start,
 726         __initcall2_start,
 727         __initcall3_start,
 728         __initcall4_start,
 729         __initcall5_start,
 730         __initcall6_start,
 731         __initcall7_start,
 732         __initcall_end,
 733 };
 734
 735 /* Keep these in sync with initcalls in include/linux/init.h */
 736 static char *initcall_level_names[] __initdata = {
 737         "early",
 738         "core",
 739         "postcore",
 740         "arch",
 741         "subsys",
 742         "fs",
 743         "device",
 744         "late",
 745 };
 746
 747 static void __init do_initcall_level(int level)
 748 {
 749         extern const struct kernel_param __start___param[], __stop___param[];
 750         initcall_t *fn;
 751
 752         strcpy(static_command_line, saved_command_line);
 753         parse_args(initcall_level_names[level],
 754                    static_command_line, __start___param,
 755                    __stop___param - __start___param,
 756                    level, level,
 757                    &repair_env_string);
 758
 759         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 760                 do_one_initcall(*fn);
 761 }
 762
 763 static void __init do_initcalls(void)
 764 {
 765         int level;
 766
 767         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 768                 do_initcall_level(level);
 769 }
 770
 771 /*
 772  * Ok, the machine is now initialized. None of the devices
 773  * have been touched yet, but the CPU subsystem is up and
 774  * running, and memory and process management works.
 775  *
 776  * Now we can finally start doing some real work..
 777  */
 778 static void __init do_basic_setup(void)
 779 {
 780         cpuset_init_smp();
 781         usermodehelper_init();
 782         shmem_init();
 783         driver_init();
 784         init_irq_proc();
 785         do_ctors();
 786         usermodehelper_enable();
 787         do_initcalls();
 788         random_int_secret_init();
 789 }
 790
 791 static 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  */
 805 void __init load_default_modules(void)
 806 {
 807         load_default_elevator_module();
 808 }
 809
 810 static 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
 818 static noinline void __init kernel_init_freeable(void);
 819
 820 static 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                 pr_err("Failed to execute %s\n", ramdisk_execute_command);
 836         }
 837
 838         /*
 839          * We try each of these until one succeeds.
 840          *
 841          * The Bourne shell can be used instead of init if we are
 842          * trying to recover a really broken machine.
 843          */
 844         if (execute_command) {
 845                 if (!run_init_process(execute_command))
 846                         return 0;
 847                 pr_err("Failed to execute %s.  Attempting defaults...\n",
 848                         execute_command);
 849         }
 850         if (!run_init_process("/sbin/init") ||
 851             !run_init_process("/etc/init") ||
 852             !run_init_process("/bin/init") ||
 853             !run_init_process("/bin/sh"))
 854                 return 0;
 855
 856         panic("No init found.  Try passing init= option to kernel. "
 857               "See Linux Documentation/init.txt for guidance.");
 858 }
 859
 860 static noinline void __init kernel_init_freeable(void)
 861 {
 862         /*
 863          * Wait until kthreadd is all set-up.
 864          */
 865         wait_for_completion(&kthreadd_done);
 866
 867         /* Now the scheduler is fully set up and can do blocking allocations */
 868         gfp_allowed_mask = __GFP_BITS_MASK;
 869
 870         /*
 871          * init can allocate pages on any node
 872          */
 873         set_mems_allowed(node_states[N_MEMORY]);
 874         /*
 875          * init can run on any cpu.
 876          */
 877         set_cpus_allowed_ptr(current, cpu_all_mask);
 878
 879         cad_pid = task_pid(current);
 880
 881         smp_prepare_cpus(setup_max_cpus);
 882
 883         do_pre_smp_initcalls();
 884         lockup_detector_init();
 885
 886         smp_init();
 887         sched_init_smp();
 888
 889         do_basic_setup();
 890
 891         /* Open the /dev/console on the rootfs, this should never fail */
 892         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 893                 pr_err("Warning: unable to open an initial console.\n");
 894
 895         (void) sys_dup(0);
 896         (void) sys_dup(0);
 897         /*
 898          * check if there is an early userspace init.  If yes, let it do all
 899          * the work
 900          */
 901
 902         if (!ramdisk_execute_command)
 903                 ramdisk_execute_command = "/init";
 904
 905         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 906                 ramdisk_execute_command = NULL;
 907                 prepare_namespace();
 908         }
 909
 910         /*
 911          * Ok, we have completed the initial bootup, and
 912          * we're essentially up and running. Get rid of the
 913          * initmem segments and start the user-mode stuff..
 914          */
 915
 916         /* rootfs is available now, try loading default modules */
 917         load_default_modules();
 918 }