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 #include <linux/file.h>
  72 #include <linux/ptrace.h>
  73
  74 #include <asm/io.h>
  75 #include <asm/bugs.h>
  76 #include <asm/setup.h>
  77 #include <asm/sections.h>
  78 #include <asm/cacheflush.h>
  79
  80 #ifdef CONFIG_X86_LOCAL_APIC
  81 #include <asm/smp.h>
  82 #endif
  83
  84 static int kernel_init(void *);
  85
  86 extern void init_IRQ(void);
  87 extern void fork_init(unsigned long);
  88 extern void mca_init(void);
  89 extern void sbus_init(void);
  90 extern void radix_tree_init(void);
  91 #ifndef CONFIG_DEBUG_RODATA
  92 static inline void mark_rodata_ro(void) { }
  93 #endif
  94
  95 #ifdef CONFIG_TC
  96 extern void tc_init(void);
  97 #endif
  98
  99 /*
 100  * Debug helper: via this flag we know that we are in 'early bootup code'
 101  * where only the boot processor is running with IRQ disabled.  This means
 102  * two things - IRQ must not be enabled before the flag is cleared and some
 103  * operations which are not allowed with IRQ disabled are allowed while the
 104  * flag is set.
 105  */
 106 bool early_boot_irqs_disabled __read_mostly;
 107
 108 enum system_states system_state __read_mostly;
 109 EXPORT_SYMBOL(system_state);
 110
 111 /*
 112  * Boot command-line arguments
 113  */
 114 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 115 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 116
 117 extern void time_init(void);
 118 /* Default late time init is NULL. archs can override this later. */
 119 void (*__initdata late_time_init)(void);
 120 extern void softirq_init(void);
 121
 122 /* Untouched command line saved by arch-specific code. */
 123 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 124 /* Untouched saved command line (eg. for /proc) */
 125 char *saved_command_line;
 126 /* Command line for parameter parsing */
 127 static char *static_command_line;
 128
 129 static char *execute_command;
 130 static char *ramdisk_execute_command;
 131
 132 /*
 133  * If set, this is an indication to the drivers that reset the underlying
 134  * device before going ahead with the initialization otherwise driver might
 135  * rely on the BIOS and skip the reset operation.
 136  *
 137  * This is useful if kernel is booting in an unreliable environment.
 138  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 139  * skipped and devices will be in unknown state.
 140  */
 141 unsigned int reset_devices;
 142 EXPORT_SYMBOL(reset_devices);
 143
 144 static int __init set_reset_devices(char *str)
 145 {
 146         reset_devices = 1;
 147         return 1;
 148 }
 149
 150 __setup("reset_devices", set_reset_devices);
 151
 152 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 153 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 154 static const char *panic_later, *panic_param;
 155
 156 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 157
 158 static int __init obsolete_checksetup(char *line)
 159 {
 160         const struct obs_kernel_param *p;
 161         int had_early_param = 0;
 162
 163         p = __setup_start;
 164         do {
 165                 int n = strlen(p->str);
 166                 if (parameqn(line, p->str, n)) {
 167                         if (p->early) {
 168                                 /* Already done in parse_early_param?
 169                                  * (Needs exact match on param part).
 170                                  * Keep iterating, as we can have early
 171                                  * params and __setups of same names 8( */
 172                                 if (line[n] == '\0' || line[n] == '=')
 173                                         had_early_param = 1;
 174                         } else if (!p->setup_func) {
 175                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 176                                        " ignored\n", p->str);
 177                                 return 1;
 178                         } else if (p->setup_func(line + n))
 179                                 return 1;
 180                 }
 181                 p++;
 182         } while (p < __setup_end);
 183
 184         return had_early_param;
 185 }
 186
 187 /*
 188  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 189  * still work even if initially too large, it will just take slightly longer
 190  */
 191 unsigned long loops_per_jiffy = (1<<12);
 192
 193 EXPORT_SYMBOL(loops_per_jiffy);
 194
 195 static int __init debug_kernel(char *str)
 196 {
 197         console_loglevel = 10;
 198         return 0;
 199 }
 200
 201 static int __init quiet_kernel(char *str)
 202 {
 203         console_loglevel = 4;
 204         return 0;
 205 }
 206
 207 early_param("debug", debug_kernel);
 208 early_param("quiet", quiet_kernel);
 209
 210 static int __init loglevel(char *str)
 211 {
 212         int newlevel;
 213
 214         /*
 215          * Only update loglevel value when a correct setting was passed,
 216          * to prevent blind crashes (when loglevel being set to 0) that
 217          * are quite hard to debug
 218          */
 219         if (get_option(&str, &newlevel)) {
 220                 console_loglevel = newlevel;
 221                 return 0;
 222         }
 223
 224         return -EINVAL;
 225 }
 226
 227 early_param("loglevel", loglevel);
 228
 229 /* Change NUL term back to "=", to make "param" the whole string. */
 230 static int __init repair_env_string(char *param, char *val, const char *unused)
 231 {
 232         if (val) {
 233                 /* param=val or param="val"? */
 234                 if (val == param+strlen(param)+1)
 235                         val[-1] = '=';
 236                 else if (val == param+strlen(param)+2) {
 237                         val[-2] = '=';
 238                         memmove(val-1, val, strlen(val)+1);
 239                         val--;
 240                 } else
 241                         BUG();
 242         }
 243         return 0;
 244 }
 245
 246 /*
 247  * Unknown boot options get handed to init, unless they look like
 248  * unused parameters (modprobe will find them in /proc/cmdline).
 249  */
 250 static int __init unknown_bootoption(char *param, char *val, const char *unused)
 251 {
 252         repair_env_string(param, val, unused);
 253
 254         /* Handle obsolete-style parameters */
 255         if (obsolete_checksetup(param))
 256                 return 0;
 257
 258         /* Unused module parameter. */
 259         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 260                 return 0;
 261
 262         if (panic_later)
 263                 return 0;
 264
 265         if (val) {
 266                 /* Environment option */
 267                 unsigned int i;
 268                 for (i = 0; envp_init[i]; i++) {
 269                         if (i == MAX_INIT_ENVS) {
 270                                 panic_later = "Too many boot env vars at `%s'";
 271                                 panic_param = param;
 272                         }
 273                         if (!strncmp(param, envp_init[i], val - param))
 274                                 break;
 275                 }
 276                 envp_init[i] = param;
 277         } else {
 278                 /* Command line option */
 279                 unsigned int i;
 280                 for (i = 0; argv_init[i]; i++) {
 281                         if (i == MAX_INIT_ARGS) {
 282                                 panic_later = "Too many boot init vars at `%s'";
 283                                 panic_param = param;
 284                         }
 285                 }
 286                 argv_init[i] = param;
 287         }
 288         return 0;
 289 }
 290
 291 static int __init init_setup(char *str)
 292 {
 293         unsigned int i;
 294
 295         execute_command = str;
 296         /*
 297          * In case LILO is going to boot us with default command line,
 298          * it prepends "auto" before the whole cmdline which makes
 299          * the shell think it should execute a script with such name.
 300          * So we ignore all arguments entered _before_ init=... [MJ]
 301          */
 302         for (i = 1; i < MAX_INIT_ARGS; i++)
 303                 argv_init[i] = NULL;
 304         return 1;
 305 }
 306 __setup("init=", init_setup);
 307
 308 static int __init rdinit_setup(char *str)
 309 {
 310         unsigned int i;
 311
 312         ramdisk_execute_command = str;
 313         /* See "auto" comment in init_setup */
 314         for (i = 1; i < MAX_INIT_ARGS; i++)
 315                 argv_init[i] = NULL;
 316         return 1;
 317 }
 318 __setup("rdinit=", rdinit_setup);
 319
 320 #ifndef CONFIG_SMP
 321 static const unsigned int setup_max_cpus = NR_CPUS;
 322 #ifdef CONFIG_X86_LOCAL_APIC
 323 static void __init smp_init(void)
 324 {
 325         APIC_init_uniprocessor();
 326 }
 327 #else
 328 #define smp_init()      do { } while (0)
 329 #endif
 330
 331 static inline void setup_nr_cpu_ids(void) { }
 332 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 333 #endif
 334
 335 /*
 336  * We need to store the untouched command line for future reference.
 337  * We also need to store the touched command line since the parameter
 338  * parsing is performed in place, and we should allow a component to
 339  * store reference of name/value for future reference.
 340  */
 341 static void __init setup_command_line(char *command_line)
 342 {
 343         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 344         static_command_line = alloc_bootmem(strlen (command_line)+1);
 345         strcpy (saved_command_line, boot_command_line);
 346         strcpy (static_command_line, command_line);
 347 }
 348
 349 /*
 350  * We need to finalize in a non-__init function or else race conditions
 351  * between the root thread and the init thread may cause start_kernel to
 352  * be reaped by free_initmem before the root thread has proceeded to
 353  * cpu_idle.
 354  *
 355  * gcc-3.4 accidentally inlines this function, so use noinline.
 356  */
 357
 358 static __initdata DECLARE_COMPLETION(kthreadd_done);
 359
 360 static noinline void __init_refok rest_init(void)
 361 {
 362         int pid;
 363
 364         rcu_scheduler_starting();
 365         /*
 366          * We need to spawn init first so that it obtains pid 1, however
 367          * the init task will end up wanting to create kthreads, which, if
 368          * we schedule it before we create kthreadd, will OOPS.
 369          */
 370         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 371         numa_default_policy();
 372         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 373         rcu_read_lock();
 374         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 375         rcu_read_unlock();
 376         complete(&kthreadd_done);
 377
 378         /*
 379          * The boot idle thread must execute schedule()
 380          * at least once to get things moving:
 381          */
 382         init_idle_bootup_task(current);
 383         schedule_preempt_disabled();
 384         /* Call into cpu_idle with preempt disabled */
 385         cpu_idle();
 386 }
 387
 388 /* Check for early params. */
 389 static int __init do_early_param(char *param, char *val, const char *unused)
 390 {
 391         const struct obs_kernel_param *p;
 392
 393         for (p = __setup_start; p < __setup_end; p++) {
 394                 if ((p->early && parameq(param, p->str)) ||
 395                     (strcmp(param, "console") == 0 &&
 396                      strcmp(p->str, "earlycon") == 0)
 397                 ) {
 398                         if (p->setup_func(val) != 0)
 399                                 printk(KERN_WARNING
 400                                        "Malformed early option '%s'\n", param);
 401                 }
 402         }
 403         /* We accept everything at this stage. */
 404         return 0;
 405 }
 406
 407 void __init parse_early_options(char *cmdline)
 408 {
 409         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 410 }
 411
 412 /* Arch code calls this early on, or if not, just before other parsing. */
 413 void __init parse_early_param(void)
 414 {
 415         static __initdata int done = 0;
 416         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 417
 418         if (done)
 419                 return;
 420
 421         /* All fall through to do_early_param. */
 422         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 423         parse_early_options(tmp_cmdline);
 424         done = 1;
 425 }
 426
 427 /*
 428  *      Activate the first processor.
 429  */
 430
 431 static void __init boot_cpu_init(void)
 432 {
 433         int cpu = smp_processor_id();
 434         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 435         set_cpu_online(cpu, true);
 436         set_cpu_active(cpu, true);
 437         set_cpu_present(cpu, true);
 438         set_cpu_possible(cpu, true);
 439 }
 440
 441 void __init __weak smp_setup_processor_id(void)
 442 {
 443 }
 444
 445 # if THREAD_SIZE >= PAGE_SIZE
 446 void __init __weak thread_info_cache_init(void)
 447 {
 448 }
 449 #endif
 450
 451 /*
 452  * Set up kernel memory allocators
 453  */
 454 static void __init mm_init(void)
 455 {
 456         /*
 457          * page_cgroup requires contiguous pages,
 458          * bigger than MAX_ORDER unless SPARSEMEM.
 459          */
 460         page_cgroup_init_flatmem();
 461         mem_init();
 462         kmem_cache_init();
 463         percpu_init_late();
 464         pgtable_cache_init();
 465         vmalloc_init();
 466 }
 467
 468 asmlinkage void __init start_kernel(void)
 469 {
 470         char * command_line;
 471         extern const struct kernel_param __start___param[], __stop___param[];
 472
 473         /*
 474          * Need to run as early as possible, to initialize the
 475          * lockdep hash:
 476          */
 477         lockdep_init();
 478         smp_setup_processor_id();
 479         debug_objects_early_init();
 480
 481         /*
 482          * Set up the the initial canary ASAP:
 483          */
 484         boot_init_stack_canary();
 485
 486         cgroup_init_early();
 487
 488         local_irq_disable();
 489         early_boot_irqs_disabled = true;
 490
 491 /*
 492  * Interrupts are still disabled. Do necessary setups, then
 493  * enable them
 494  */
 495         tick_init();
 496         boot_cpu_init();
 497         page_address_init();
 498         printk(KERN_NOTICE "%s", linux_banner);
 499         setup_arch(&command_line);
 500         mm_init_owner(&init_mm, &init_task);
 501         mm_init_cpumask(&init_mm);
 502         setup_command_line(command_line);
 503         setup_nr_cpu_ids();
 504         setup_per_cpu_areas();
 505         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 506
 507         build_all_zonelists(NULL, NULL);
 508         page_alloc_init();
 509
 510         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 511         parse_early_param();
 512         parse_args("Booting kernel", static_command_line, __start___param,
 513                    __stop___param - __start___param,
 514                    -1, -1, &unknown_bootoption);
 515
 516         jump_label_init();
 517
 518         /*
 519          * These use large bootmem allocations and must precede
 520          * kmem_cache_init()
 521          */
 522         setup_log_buf(0);
 523         pidhash_init();
 524         vfs_caches_init_early();
 525         sort_main_extable();
 526         trap_init();
 527         mm_init();
 528
 529         /*
 530          * Set up the scheduler prior starting any interrupts (such as the
 531          * timer interrupt). Full topology setup happens at smp_init()
 532          * time - but meanwhile we still have a functioning scheduler.
 533          */
 534         sched_init();
 535         /*
 536          * Disable preemption - early bootup scheduling is extremely
 537          * fragile until we cpu_idle() for the first time.
 538          */
 539         preempt_disable();
 540         if (!irqs_disabled()) {
 541                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 542                                 "enabled *very* early, fixing it\n");
 543                 local_irq_disable();
 544         }
 545         idr_init_cache();
 546         perf_event_init();
 547         rcu_init();
 548         radix_tree_init();
 549         /* init some links before init_ISA_irqs() */
 550         early_irq_init();
 551         init_IRQ();
 552         init_timers();
 553         hrtimers_init();
 554         softirq_init();
 555         timekeeping_init();
 556         time_init();
 557         profile_init();
 558         call_function_init();
 559         if (!irqs_disabled())
 560                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 561                                  "enabled early\n");
 562         early_boot_irqs_disabled = false;
 563         local_irq_enable();
 564
 565         kmem_cache_init_late();
 566
 567         /*
 568          * HACK ALERT! This is early. We're enabling the console before
 569          * we've done PCI setups etc, and console_init() must be aware of
 570          * this. But we do want output early, in case something goes wrong.
 571          */
 572         console_init();
 573         if (panic_later)
 574                 panic(panic_later, panic_param);
 575
 576         lockdep_info();
 577
 578         /*
 579          * Need to run this when irqs are enabled, because it wants
 580          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 581          * too:
 582          */
 583         locking_selftest();
 584
 585 #ifdef CONFIG_BLK_DEV_INITRD
 586         if (initrd_start && !initrd_below_start_ok &&
 587             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 588                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 589                     "disabling it.\n",
 590                     page_to_pfn(virt_to_page((void *)initrd_start)),
 591                     min_low_pfn);
 592                 initrd_start = 0;
 593         }
 594 #endif
 595         page_cgroup_init();
 596         debug_objects_mem_init();
 597         kmemleak_init();
 598         setup_per_cpu_pageset();
 599         numa_policy_init();
 600         if (late_time_init)
 601                 late_time_init();
 602         sched_clock_init();
 603         calibrate_delay();
 604         pidmap_init();
 605         anon_vma_init();
 606 #ifdef CONFIG_X86
 607         if (efi_enabled)
 608                 efi_enter_virtual_mode();
 609 #endif
 610         thread_info_cache_init();
 611         cred_init();
 612         fork_init(totalram_pages);
 613         proc_caches_init();
 614         buffer_init();
 615         key_init();
 616         security_init();
 617         dbg_late_init();
 618         vfs_caches_init(totalram_pages);
 619         signals_init();
 620         /* rootfs populating might need page-writeback */
 621         page_writeback_init();
 622 #ifdef CONFIG_PROC_FS
 623         proc_root_init();
 624 #endif
 625         cgroup_init();
 626         cpuset_init();
 627         taskstats_init_early();
 628         delayacct_init();
 629
 630         check_bugs();
 631
 632         acpi_early_init(); /* before LAPIC and SMP init */
 633         sfi_init_late();
 634
 635         if (efi_enabled) {
 636                 efi_late_init();
 637                 efi_free_boot_services();
 638         }
 639
 640         ftrace_init();
 641
 642         /* Do the rest non-__init'ed, we're now alive */
 643         rest_init();
 644 }
 645
 646 /* Call all constructor functions linked into the kernel. */
 647 static void __init do_ctors(void)
 648 {
 649 #ifdef CONFIG_CONSTRUCTORS
 650         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 651
 652         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 653                 (*fn)();
 654 #endif
 655 }
 656
 657 bool initcall_debug;
 658 core_param(initcall_debug, initcall_debug, bool, 0644);
 659
 660 static char msgbuf[64];
 661
 662 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 663 {
 664         ktime_t calltime, delta, rettime;
 665         unsigned long long duration;
 666         int ret;
 667
 668         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 669         calltime = ktime_get();
 670         ret = fn();
 671         rettime = ktime_get();
 672         delta = ktime_sub(rettime, calltime);
 673         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 674         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 675                 ret, duration);
 676
 677         return ret;
 678 }
 679
 680 int __init_or_module do_one_initcall(initcall_t fn)
 681 {
 682         int count = preempt_count();
 683         int ret;
 684
 685         if (initcall_debug)
 686                 ret = do_one_initcall_debug(fn);
 687         else
 688                 ret = fn();
 689
 690         msgbuf[0] = 0;
 691
 692         if (ret && ret != -ENODEV && initcall_debug)
 693                 sprintf(msgbuf, "error code %d ", ret);
 694
 695         if (preempt_count() != count) {
 696                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 697                 preempt_count() = count;
 698         }
 699         if (irqs_disabled()) {
 700                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 701                 local_irq_enable();
 702         }
 703         if (msgbuf[0]) {
 704                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 705         }
 706
 707         return ret;
 708 }
 709
 710
 711 extern initcall_t __initcall_start[];
 712 extern initcall_t __initcall0_start[];
 713 extern initcall_t __initcall1_start[];
 714 extern initcall_t __initcall2_start[];
 715 extern initcall_t __initcall3_start[];
 716 extern initcall_t __initcall4_start[];
 717 extern initcall_t __initcall5_start[];
 718 extern initcall_t __initcall6_start[];
 719 extern initcall_t __initcall7_start[];
 720 extern initcall_t __initcall_end[];
 721
 722 static initcall_t *initcall_levels[] __initdata = {
 723         __initcall0_start,
 724         __initcall1_start,
 725         __initcall2_start,
 726         __initcall3_start,
 727         __initcall4_start,
 728         __initcall5_start,
 729         __initcall6_start,
 730         __initcall7_start,
 731         __initcall_end,
 732 };
 733
 734 /* Keep these in sync with initcalls in include/linux/init.h */
 735 static char *initcall_level_names[] __initdata = {
 736         "early",
 737         "core",
 738         "postcore",
 739         "arch",
 740         "subsys",
 741         "fs",
 742         "device",
 743         "late",
 744 };
 745
 746 static void __init do_initcall_level(int level)
 747 {
 748         extern const struct kernel_param __start___param[], __stop___param[];
 749         initcall_t *fn;
 750
 751         strcpy(static_command_line, saved_command_line);
 752         parse_args(initcall_level_names[level],
 753                    static_command_line, __start___param,
 754                    __stop___param - __start___param,
 755                    level, level,
 756                    &repair_env_string);
 757
 758         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 759                 do_one_initcall(*fn);
 760 }
 761
 762 static void __init do_initcalls(void)
 763 {
 764         int level;
 765
 766         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 767                 do_initcall_level(level);
 768 }
 769
 770 /*
 771  * Ok, the machine is now initialized. None of the devices
 772  * have been touched yet, but the CPU subsystem is up and
 773  * running, and memory and process management works.
 774  *
 775  * Now we can finally start doing some real work..
 776  */
 777 static void __init do_basic_setup(void)
 778 {
 779         cpuset_init_smp();
 780         usermodehelper_init();
 781         shmem_init();
 782         driver_init();
 783         init_irq_proc();
 784         do_ctors();
 785         usermodehelper_enable();
 786         do_initcalls();
 787 }
 788
 789 static void __init do_pre_smp_initcalls(void)
 790 {
 791         initcall_t *fn;
 792
 793         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 794                 do_one_initcall(*fn);
 795 }
 796
 797 static int run_init_process(const char *init_filename)
 798 {
 799         argv_init[0] = init_filename;
 800         return kernel_execve(init_filename, argv_init, envp_init);
 801 }
 802
 803 static void __init kernel_init_freeable(void);
 804
 805 static int __ref kernel_init(void *unused)
 806 {
 807         kernel_init_freeable();
 808         /* need to finish all async __init code before freeing the memory */
 809         async_synchronize_full();
 810         free_initmem();
 811         mark_rodata_ro();
 812         system_state = SYSTEM_RUNNING;
 813         numa_default_policy();
 814
 815         current->signal->flags |= SIGNAL_UNKILLABLE;
 816         flush_delayed_fput();
 817
 818         if (ramdisk_execute_command) {
 819                 if (!run_init_process(ramdisk_execute_command))
 820                         return 0;
 821                 printk(KERN_WARNING "Failed to execute %s\n",
 822                                 ramdisk_execute_command);
 823         }
 824
 825         /*
 826          * We try each of these until one succeeds.
 827          *
 828          * The Bourne shell can be used instead of init if we are
 829          * trying to recover a really broken machine.
 830          */
 831         if (execute_command) {
 832                 if (!run_init_process(execute_command))
 833                         return 0;
 834                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 835                                         "defaults...\n", execute_command);
 836         }
 837         if (!run_init_process("/sbin/init") ||
 838             !run_init_process("/etc/init") ||
 839             !run_init_process("/bin/init") ||
 840             !run_init_process("/bin/sh"))
 841                 return 0;
 842
 843         panic("No init found.  Try passing init= option to kernel. "
 844               "See Linux Documentation/init.txt for guidance.");
 845 }
 846
 847 static void __init kernel_init_freeable(void)
 848 {
 849         /*
 850          * Wait until kthreadd is all set-up.
 851          */
 852         wait_for_completion(&kthreadd_done);
 853
 854         /* Now the scheduler is fully set up and can do blocking allocations */
 855         gfp_allowed_mask = __GFP_BITS_MASK;
 856
 857         /*
 858          * init can allocate pages on any node
 859          */
 860         set_mems_allowed(node_states[N_MEMORY]);
 861         /*
 862          * init can run on any cpu.
 863          */
 864         set_cpus_allowed_ptr(current, cpu_all_mask);
 865
 866         cad_pid = task_pid(current);
 867
 868         smp_prepare_cpus(setup_max_cpus);
 869
 870         do_pre_smp_initcalls();
 871         lockup_detector_init();
 872
 873         smp_init();
 874         sched_init_smp();
 875
 876         do_basic_setup();
 877
 878         /* Open the /dev/console on the rootfs, this should never fail */
 879         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 880                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 881
 882         (void) sys_dup(0);
 883         (void) sys_dup(0);
 884         /*
 885          * check if there is an early userspace init.  If yes, let it do all
 886          * the work
 887          */
 888
 889         if (!ramdisk_execute_command)
 890                 ramdisk_execute_command = "/init";
 891
 892         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 893                 ramdisk_execute_command = NULL;
 894                 prepare_namespace();
 895         }
 896
 897         /*
 898          * Ok, we have completed the initial bootup, and
 899          * we're essentially up and running. Get rid of the
 900          * initmem segments and start the user-mode stuff..
 901          */
 902 }