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 #include <linux/types.h>
  13 #include <linux/module.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/kernel.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/stackprotector.h>
  18 #include <linux/string.h>
  19 #include <linux/ctype.h>
  20 #include <linux/delay.h>
  21 #include <linux/ioport.h>
  22 #include <linux/init.h>
  23 #include <linux/initrd.h>
  24 #include <linux/bootmem.h>
  25 #include <linux/acpi.h>
  26 #include <linux/tty.h>
  27 #include <linux/percpu.h>
  28 #include <linux/kmod.h>
  29 #include <linux/vmalloc.h>
  30 #include <linux/kernel_stat.h>
  31 #include <linux/start_kernel.h>
  32 #include <linux/security.h>
  33 #include <linux/smp.h>
  34 #include <linux/profile.h>
  35 #include <linux/rcupdate.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/kallsyms.h>
  38 #include <linux/writeback.h>
  39 #include <linux/cpu.h>
  40 #include <linux/cpuset.h>
  41 #include <linux/cgroup.h>
  42 #include <linux/efi.h>
  43 #include <linux/tick.h>
  44 #include <linux/interrupt.h>
  45 #include <linux/taskstats_kern.h>
  46 #include <linux/delayacct.h>
  47 #include <linux/unistd.h>
  48 #include <linux/rmap.h>
  49 #include <linux/mempolicy.h>
  50 #include <linux/key.h>
  51 #include <linux/buffer_head.h>
  52 #include <linux/page_cgroup.h>
  53 #include <linux/debug_locks.h>
  54 #include <linux/debugobjects.h>
  55 #include <linux/lockdep.h>
  56 #include <linux/kmemleak.h>
  57 #include <linux/pid_namespace.h>
  58 #include <linux/device.h>
  59 #include <linux/kthread.h>
  60 #include <linux/sched.h>
  61 #include <linux/signal.h>
  62 #include <linux/idr.h>
  63 #include <linux/kgdb.h>
  64 #include <linux/ftrace.h>
  65 #include <linux/async.h>
  66 #include <linux/kmemcheck.h>
  67 #include <linux/sfi.h>
  68 #include <linux/shmem_fs.h>
  69 #include <linux/slab.h>
  70 #include <linux/perf_event.h>
  71
  72 #include <asm/io.h>
  73 #include <asm/bugs.h>
  74 #include <asm/setup.h>
  75 #include <asm/sections.h>
  76 #include <asm/cacheflush.h>
  77
  78 #ifdef CONFIG_X86_LOCAL_APIC
  79 #include <asm/smp.h>
  80 #endif
  81
  82 static int kernel_init(void *);
  83
  84 extern void init_IRQ(void);
  85 extern void fork_init(unsigned long);
  86 extern void mca_init(void);
  87 extern void sbus_init(void);
  88 extern void prio_tree_init(void);
  89 extern void radix_tree_init(void);
  90 #ifndef CONFIG_DEBUG_RODATA
  91 static inline void mark_rodata_ro(void) { }
  92 #endif
  93
  94 #ifdef CONFIG_TC
  95 extern void tc_init(void);
  96 #endif
  97
  98 /*
  99  * Debug helper: via this flag we know that we are in 'early bootup code'
 100  * where only the boot processor is running with IRQ disabled.  This means
 101  * two things - IRQ must not be enabled before the flag is cleared and some
 102  * operations which are not allowed with IRQ disabled are allowed while the
 103  * flag is set.
 104  */
 105 bool early_boot_irqs_disabled __read_mostly;
 106
 107 enum system_states system_state __read_mostly;
 108 EXPORT_SYMBOL(system_state);
 109
 110 /*
 111  * Boot command-line arguments
 112  */
 113 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 114 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 115
 116 extern void time_init(void);
 117 /* Default late time init is NULL. archs can override this later. */
 118 void (*__initdata late_time_init)(void);
 119 extern void softirq_init(void);
 120
 121 /* Untouched command line saved by arch-specific code. */
 122 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 123 /* Untouched saved command line (eg. for /proc) */
 124 char *saved_command_line;
 125 /* Command line for parameter parsing */
 126 static char *static_command_line;
 127
 128 static char *execute_command;
 129 static char *ramdisk_execute_command;
 130
 131 /*
 132  * If set, this is an indication to the drivers that reset the underlying
 133  * device before going ahead with the initialization otherwise driver might
 134  * rely on the BIOS and skip the reset operation.
 135  *
 136  * This is useful if kernel is booting in an unreliable environment.
 137  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 138  * skipped and devices will be in unknown state.
 139  */
 140 unsigned int reset_devices;
 141 EXPORT_SYMBOL(reset_devices);
 142
 143 static int __init set_reset_devices(char *str)
 144 {
 145         reset_devices = 1;
 146         return 1;
 147 }
 148
 149 __setup("reset_devices", set_reset_devices);
 150
 151 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 152 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 153 static const char *panic_later, *panic_param;
 154
 155 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 156
 157 static int __init obsolete_checksetup(char *line)
 158 {
 159         const struct obs_kernel_param *p;
 160         int had_early_param = 0;
 161
 162         p = __setup_start;
 163         do {
 164                 int n = strlen(p->str);
 165                 if (parameqn(line, p->str, n)) {
 166                         if (p->early) {
 167                                 /* Already done in parse_early_param?
 168                                  * (Needs exact match on param part).
 169                                  * Keep iterating, as we can have early
 170                                  * params and __setups of same names 8( */
 171                                 if (line[n] == '\0' || line[n] == '=')
 172                                         had_early_param = 1;
 173                         } else if (!p->setup_func) {
 174                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 175                                        " ignored\n", p->str);
 176                                 return 1;
 177                         } else if (p->setup_func(line + n))
 178                                 return 1;
 179                 }
 180                 p++;
 181         } while (p < __setup_end);
 182
 183         return had_early_param;
 184 }
 185
 186 /*
 187  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 188  * still work even if initially too large, it will just take slightly longer
 189  */
 190 unsigned long loops_per_jiffy = (1<<12);
 191
 192 EXPORT_SYMBOL(loops_per_jiffy);
 193
 194 static int __init debug_kernel(char *str)
 195 {
 196         console_loglevel = 10;
 197         return 0;
 198 }
 199
 200 static int __init quiet_kernel(char *str)
 201 {
 202         console_loglevel = 4;
 203         return 0;
 204 }
 205
 206 early_param("debug", debug_kernel);
 207 early_param("quiet", quiet_kernel);
 208
 209 static int __init loglevel(char *str)
 210 {
 211         int newlevel;
 212
 213         /*
 214          * Only update loglevel value when a correct setting was passed,
 215          * to prevent blind crashes (when loglevel being set to 0) that
 216          * are quite hard to debug
 217          */
 218         if (get_option(&str, &newlevel)) {
 219                 console_loglevel = newlevel;
 220                 return 0;
 221         }
 222
 223         return -EINVAL;
 224 }
 225
 226 early_param("loglevel", loglevel);
 227
 228 /* Change NUL term back to "=", to make "param" the whole string. */
 229 static int __init repair_env_string(char *param, char *val)
 230 {
 231         if (val) {
 232                 /* param=val or param="val"? */
 233                 if (val == param+strlen(param)+1)
 234                         val[-1] = '=';
 235                 else if (val == param+strlen(param)+2) {
 236                         val[-2] = '=';
 237                         memmove(val-1, val, strlen(val)+1);
 238                         val--;
 239                 } else
 240                         BUG();
 241         }
 242         return 0;
 243 }
 244
 245 /*
 246  * Unknown boot options get handed to init, unless they look like
 247  * unused parameters (modprobe will find them in /proc/cmdline).
 248  */
 249 static int __init unknown_bootoption(char *param, char *val)
 250 {
 251         repair_env_string(param, val);
 252
 253         /* Handle obsolete-style parameters */
 254         if (obsolete_checksetup(param))
 255                 return 0;
 256
 257         /* Unused module parameter. */
 258         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 259                 return 0;
 260
 261         if (panic_later)
 262                 return 0;
 263
 264         if (val) {
 265                 /* Environment option */
 266                 unsigned int i;
 267                 for (i = 0; envp_init[i]; i++) {
 268                         if (i == MAX_INIT_ENVS) {
 269                                 panic_later = "Too many boot env vars at `%s'";
 270                                 panic_param = param;
 271                         }
 272                         if (!strncmp(param, envp_init[i], val - param))
 273                                 break;
 274                 }
 275                 envp_init[i] = param;
 276         } else {
 277                 /* Command line option */
 278                 unsigned int i;
 279                 for (i = 0; argv_init[i]; i++) {
 280                         if (i == MAX_INIT_ARGS) {
 281                                 panic_later = "Too many boot init vars at `%s'";
 282                                 panic_param = param;
 283                         }
 284                 }
 285                 argv_init[i] = param;
 286         }
 287         return 0;
 288 }
 289
 290 static int __init init_setup(char *str)
 291 {
 292         unsigned int i;
 293
 294         execute_command = str;
 295         /*
 296          * In case LILO is going to boot us with default command line,
 297          * it prepends "auto" before the whole cmdline which makes
 298          * the shell think it should execute a script with such name.
 299          * So we ignore all arguments entered _before_ init=... [MJ]
 300          */
 301         for (i = 1; i < MAX_INIT_ARGS; i++)
 302                 argv_init[i] = NULL;
 303         return 1;
 304 }
 305 __setup("init=", init_setup);
 306
 307 static int __init rdinit_setup(char *str)
 308 {
 309         unsigned int i;
 310
 311         ramdisk_execute_command = str;
 312         /* See "auto" comment in init_setup */
 313         for (i = 1; i < MAX_INIT_ARGS; i++)
 314                 argv_init[i] = NULL;
 315         return 1;
 316 }
 317 __setup("rdinit=", rdinit_setup);
 318
 319 #ifndef CONFIG_SMP
 320 static const unsigned int setup_max_cpus = NR_CPUS;
 321 #ifdef CONFIG_X86_LOCAL_APIC
 322 static void __init smp_init(void)
 323 {
 324         APIC_init_uniprocessor();
 325 }
 326 #else
 327 #define smp_init()      do { } while (0)
 328 #endif
 329
 330 static inline void setup_nr_cpu_ids(void) { }
 331 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 332 #endif
 333
 334 /*
 335  * We need to store the untouched command line for future reference.
 336  * We also need to store the touched command line since the parameter
 337  * parsing is performed in place, and we should allow a component to
 338  * store reference of name/value for future reference.
 339  */
 340 static void __init setup_command_line(char *command_line)
 341 {
 342         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 343         static_command_line = alloc_bootmem(strlen (command_line)+1);
 344         strcpy (saved_command_line, boot_command_line);
 345         strcpy (static_command_line, command_line);
 346 }
 347
 348 /*
 349  * We need to finalize in a non-__init function or else race conditions
 350  * between the root thread and the init thread may cause start_kernel to
 351  * be reaped by free_initmem before the root thread has proceeded to
 352  * cpu_idle.
 353  *
 354  * gcc-3.4 accidentally inlines this function, so use noinline.
 355  */
 356
 357 static __initdata DECLARE_COMPLETION(kthreadd_done);
 358
 359 static noinline void __init_refok rest_init(void)
 360 {
 361         int pid;
 362
 363         rcu_scheduler_starting();
 364         /*
 365          * We need to spawn init first so that it obtains pid 1, however
 366          * the init task will end up wanting to create kthreads, which, if
 367          * we schedule it before we create kthreadd, will OOPS.
 368          */
 369         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 370         numa_default_policy();
 371         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 372         rcu_read_lock();
 373         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 374         rcu_read_unlock();
 375         complete(&kthreadd_done);
 376
 377         /*
 378          * The boot idle thread must execute schedule()
 379          * at least once to get things moving:
 380          */
 381         init_idle_bootup_task(current);
 382         schedule_preempt_disabled();
 383         /* Call into cpu_idle with preempt disabled */
 384         cpu_idle();
 385 }
 386
 387 /* Check for early params. */
 388 static int __init do_early_param(char *param, char *val)
 389 {
 390         const struct obs_kernel_param *p;
 391
 392         for (p = __setup_start; p < __setup_end; p++) {
 393                 if ((p->early && parameq(param, p->str)) ||
 394                     (strcmp(param, "console") == 0 &&
 395                      strcmp(p->str, "earlycon") == 0)
 396                 ) {
 397                         if (p->setup_func(val) != 0)
 398                                 printk(KERN_WARNING
 399                                        "Malformed early option '%s'\n", param);
 400                 }
 401         }
 402         /* We accept everything at this stage. */
 403         return 0;
 404 }
 405
 406 void __init parse_early_options(char *cmdline)
 407 {
 408         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 409 }
 410
 411 /* Arch code calls this early on, or if not, just before other parsing. */
 412 void __init parse_early_param(void)
 413 {
 414         static __initdata int done = 0;
 415         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 416
 417         if (done)
 418                 return;
 419
 420         /* All fall through to do_early_param. */
 421         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 422         parse_early_options(tmp_cmdline);
 423         done = 1;
 424 }
 425
 426 /*
 427  *      Activate the first processor.
 428  */
 429
 430 static void __init boot_cpu_init(void)
 431 {
 432         int cpu = smp_processor_id();
 433         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 434         set_cpu_online(cpu, true);
 435         set_cpu_active(cpu, true);
 436         set_cpu_present(cpu, true);
 437         set_cpu_possible(cpu, true);
 438 }
 439
 440 void __init __weak smp_setup_processor_id(void)
 441 {
 442 }
 443
 444 void __init __weak thread_info_cache_init(void)
 445 {
 446 }
 447
 448 /*
 449  * Set up kernel memory allocators
 450  */
 451 static void __init mm_init(void)
 452 {
 453         /*
 454          * page_cgroup requires contiguous pages,
 455          * bigger than MAX_ORDER unless SPARSEMEM.
 456          */
 457         page_cgroup_init_flatmem();
 458         mem_init();
 459         kmem_cache_init();
 460         percpu_init_late();
 461         pgtable_cache_init();
 462         vmalloc_init();
 463 }
 464
 465 asmlinkage void __init start_kernel(void)
 466 {
 467         char * command_line;
 468         extern const struct kernel_param __start___param[], __stop___param[];
 469
 470         /*
 471          * Need to run as early as possible, to initialize the
 472          * lockdep hash:
 473          */
 474         lockdep_init();
 475         smp_setup_processor_id();
 476         debug_objects_early_init();
 477
 478         /*
 479          * Set up the the initial canary ASAP:
 480          */
 481         boot_init_stack_canary();
 482
 483         cgroup_init_early();
 484
 485         local_irq_disable();
 486         early_boot_irqs_disabled = true;
 487
 488 /*
 489  * Interrupts are still disabled. Do necessary setups, then
 490  * enable them
 491  */
 492         tick_init();
 493         boot_cpu_init();
 494         page_address_init();
 495         printk(KERN_NOTICE "%s", linux_banner);
 496         setup_arch(&command_line);
 497         mm_init_owner(&init_mm, &init_task);
 498         mm_init_cpumask(&init_mm);
 499         setup_command_line(command_line);
 500         setup_nr_cpu_ids();
 501         setup_per_cpu_areas();
 502         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 503
 504         build_all_zonelists(NULL);
 505         page_alloc_init();
 506
 507         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 508         parse_early_param();
 509         parse_args("Booting kernel", static_command_line, __start___param,
 510                    __stop___param - __start___param,
 511                    0, 0, &unknown_bootoption);
 512
 513         jump_label_init();
 514
 515         /*
 516          * These use large bootmem allocations and must precede
 517          * kmem_cache_init()
 518          */
 519         setup_log_buf(0);
 520         pidhash_init();
 521         vfs_caches_init_early();
 522         sort_main_extable();
 523         trap_init();
 524         mm_init();
 525
 526         /*
 527          * Set up the scheduler prior starting any interrupts (such as the
 528          * timer interrupt). Full topology setup happens at smp_init()
 529          * time - but meanwhile we still have a functioning scheduler.
 530          */
 531         sched_init();
 532         /*
 533          * Disable preemption - early bootup scheduling is extremely
 534          * fragile until we cpu_idle() for the first time.
 535          */
 536         preempt_disable();
 537         if (!irqs_disabled()) {
 538                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 539                                 "enabled *very* early, fixing it\n");
 540                 local_irq_disable();
 541         }
 542         idr_init_cache();
 543         perf_event_init();
 544         rcu_init();
 545         radix_tree_init();
 546         /* init some links before init_ISA_irqs() */
 547         early_irq_init();
 548         init_IRQ();
 549         prio_tree_init();
 550         init_timers();
 551         hrtimers_init();
 552         softirq_init();
 553         timekeeping_init();
 554         time_init();
 555         profile_init();
 556         call_function_init();
 557         if (!irqs_disabled())
 558                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 559                                  "enabled early\n");
 560         early_boot_irqs_disabled = false;
 561         local_irq_enable();
 562
 563         /* Interrupts are enabled now so all GFP allocations are safe. */
 564         gfp_allowed_mask = __GFP_BITS_MASK;
 565
 566         kmem_cache_init_late();
 567
 568         /*
 569          * HACK ALERT! This is early. We're enabling the console before
 570          * we've done PCI setups etc, and console_init() must be aware of
 571          * this. But we do want output early, in case something goes wrong.
 572          */
 573         console_init();
 574         if (panic_later)
 575                 panic(panic_later, panic_param);
 576
 577         lockdep_info();
 578
 579         /*
 580          * Need to run this when irqs are enabled, because it wants
 581          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 582          * too:
 583          */
 584         locking_selftest();
 585
 586 #ifdef CONFIG_BLK_DEV_INITRD
 587         if (initrd_start && !initrd_below_start_ok &&
 588             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 589                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 590                     "disabling it.\n",
 591                     page_to_pfn(virt_to_page((void *)initrd_start)),
 592                     min_low_pfn);
 593                 initrd_start = 0;
 594         }
 595 #endif
 596         page_cgroup_init();
 597         debug_objects_mem_init();
 598         kmemleak_init();
 599         setup_per_cpu_pageset();
 600         numa_policy_init();
 601         if (late_time_init)
 602                 late_time_init();
 603         sched_clock_init();
 604         calibrate_delay();
 605         pidmap_init();
 606         anon_vma_init();
 607 #ifdef CONFIG_X86
 608         if (efi_enabled)
 609                 efi_enter_virtual_mode();
 610 #endif
 611         thread_info_cache_init();
 612         cred_init();
 613         fork_init(totalram_pages);
 614         proc_caches_init();
 615         buffer_init();
 616         key_init();
 617         security_init();
 618         dbg_late_init();
 619         vfs_caches_init(totalram_pages);
 620         signals_init();
 621         /* rootfs populating might need page-writeback */
 622         page_writeback_init();
 623 #ifdef CONFIG_PROC_FS
 624         proc_root_init();
 625 #endif
 626         cgroup_init();
 627         cpuset_init();
 628         taskstats_init_early();
 629         delayacct_init();
 630
 631         check_bugs();
 632
 633         acpi_early_init(); /* before LAPIC and SMP init */
 634         sfi_init_late();
 635
 636         ftrace_init();
 637
 638         /* Do the rest non-__init'ed, we're now alive */
 639         rest_init();
 640 }
 641
 642 /* Call all constructor functions linked into the kernel. */
 643 static void __init do_ctors(void)
 644 {
 645 #ifdef CONFIG_CONSTRUCTORS
 646         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 647
 648         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 649                 (*fn)();
 650 #endif
 651 }
 652
 653 bool initcall_debug;
 654 core_param(initcall_debug, initcall_debug, bool, 0644);
 655
 656 static char msgbuf[64];
 657
 658 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 659 {
 660         ktime_t calltime, delta, rettime;
 661         unsigned long long duration;
 662         int ret;
 663
 664         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 665         calltime = ktime_get();
 666         ret = fn();
 667         rettime = ktime_get();
 668         delta = ktime_sub(rettime, calltime);
 669         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 670         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 671                 ret, duration);
 672
 673         return ret;
 674 }
 675
 676 int __init_or_module do_one_initcall(initcall_t fn)
 677 {
 678         int count = preempt_count();
 679         int ret;
 680
 681         if (initcall_debug)
 682                 ret = do_one_initcall_debug(fn);
 683         else
 684                 ret = fn();
 685
 686         msgbuf[0] = 0;
 687
 688         if (ret && ret != -ENODEV && initcall_debug)
 689                 sprintf(msgbuf, "error code %d ", ret);
 690
 691         if (preempt_count() != count) {
 692                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 693                 preempt_count() = count;
 694         }
 695         if (irqs_disabled()) {
 696                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 697                 local_irq_enable();
 698         }
 699         if (msgbuf[0]) {
 700                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 701         }
 702
 703         return ret;
 704 }
 705
 706
 707 extern initcall_t __initcall_start[];
 708 extern initcall_t __initcall0_start[];
 709 extern initcall_t __initcall1_start[];
 710 extern initcall_t __initcall2_start[];
 711 extern initcall_t __initcall3_start[];
 712 extern initcall_t __initcall4_start[];
 713 extern initcall_t __initcall5_start[];
 714 extern initcall_t __initcall6_start[];
 715 extern initcall_t __initcall7_start[];
 716 extern initcall_t __initcall_end[];
 717
 718 static initcall_t *initcall_levels[] __initdata = {
 719         __initcall0_start,
 720         __initcall1_start,
 721         __initcall2_start,
 722         __initcall3_start,
 723         __initcall4_start,
 724         __initcall5_start,
 725         __initcall6_start,
 726         __initcall7_start,
 727         __initcall_end,
 728 };
 729
 730 static char *initcall_level_names[] __initdata = {
 731         "early parameters",
 732         "core parameters",
 733         "postcore parameters",
 734         "arch parameters",
 735         "subsys parameters",
 736         "fs parameters",
 737         "device parameters",
 738         "late parameters",
 739 };
 740
 741 static void __init do_initcall_level(int level)
 742 {
 743         extern const struct kernel_param __start___param[], __stop___param[];
 744         initcall_t *fn;
 745
 746         strcpy(static_command_line, saved_command_line);
 747         parse_args(initcall_level_names[level],
 748                    static_command_line, __start___param,
 749                    __stop___param - __start___param,
 750                    level, level,
 751                    repair_env_string);
 752
 753         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 754                 do_one_initcall(*fn);
 755 }
 756
 757 static void __init do_initcalls(void)
 758 {
 759         int level;
 760
 761         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 762                 do_initcall_level(level);
 763 }
 764
 765 /*
 766  * Ok, the machine is now initialized. None of the devices
 767  * have been touched yet, but the CPU subsystem is up and
 768  * running, and memory and process management works.
 769  *
 770  * Now we can finally start doing some real work..
 771  */
 772 static void __init do_basic_setup(void)
 773 {
 774         cpuset_init_smp();
 775         usermodehelper_init();
 776         shmem_init();
 777         driver_init();
 778         init_irq_proc();
 779         do_ctors();
 780         usermodehelper_enable();
 781         do_initcalls();
 782 }
 783
 784 static void __init do_pre_smp_initcalls(void)
 785 {
 786         initcall_t *fn;
 787
 788         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 789                 do_one_initcall(*fn);
 790 }
 791
 792 static void run_init_process(const char *init_filename)
 793 {
 794         argv_init[0] = init_filename;
 795         kernel_execve(init_filename, argv_init, envp_init);
 796 }
 797
 798 /* This is a non __init function. Force it to be noinline otherwise gcc
 799  * makes it inline to init() and it becomes part of init.text section
 800  */
 801 static noinline int init_post(void)
 802 {
 803         /* need to finish all async __init code before freeing the memory */
 804         async_synchronize_full();
 805         free_initmem();
 806         mark_rodata_ro();
 807         system_state = SYSTEM_RUNNING;
 808         numa_default_policy();
 809
 810
 811         current->signal->flags |= SIGNAL_UNKILLABLE;
 812
 813         if (ramdisk_execute_command) {
 814                 run_init_process(ramdisk_execute_command);
 815                 printk(KERN_WARNING "Failed to execute %s\n",
 816                                 ramdisk_execute_command);
 817         }
 818
 819         /*
 820          * We try each of these until one succeeds.
 821          *
 822          * The Bourne shell can be used instead of init if we are
 823          * trying to recover a really broken machine.
 824          */
 825         if (execute_command) {
 826                 run_init_process(execute_command);
 827                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 828                                         "defaults...\n", execute_command);
 829         }
 830         run_init_process("/sbin/init");
 831         run_init_process("/etc/init");
 832         run_init_process("/bin/init");
 833         run_init_process("/bin/sh");
 834
 835         panic("No init found.  Try passing init= option to kernel. "
 836               "See Linux Documentation/init.txt for guidance.");
 837 }
 838
 839 static int __init kernel_init(void * unused)
 840 {
 841         /*
 842          * Wait until kthreadd is all set-up.
 843          */
 844         wait_for_completion(&kthreadd_done);
 845         /*
 846          * init can allocate pages on any node
 847          */
 848         set_mems_allowed(node_states[N_HIGH_MEMORY]);
 849         /*
 850          * init can run on any cpu.
 851          */
 852         set_cpus_allowed_ptr(current, cpu_all_mask);
 853
 854         cad_pid = task_pid(current);
 855
 856         smp_prepare_cpus(setup_max_cpus);
 857
 858         do_pre_smp_initcalls();
 859         lockup_detector_init();
 860
 861         smp_init();
 862         sched_init_smp();
 863
 864         do_basic_setup();
 865
 866         /* Open the /dev/console on the rootfs, this should never fail */
 867         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 868                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 869
 870         (void) sys_dup(0);
 871         (void) sys_dup(0);
 872         /*
 873          * check if there is an early userspace init.  If yes, let it do all
 874          * the work
 875          */
 876
 877         if (!ramdisk_execute_command)
 878                 ramdisk_execute_command = "/init";
 879
 880         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 881                 ramdisk_execute_command = NULL;
 882                 prepare_namespace();
 883         }
 884
 885         /*
 886          * Ok, we have completed the initial bootup, and
 887          * we're essentially up and running. Get rid of the
 888          * initmem segments and start the user-mode stuff..
 889          */
 890
 891         init_post();
 892         return 0;
 893 }