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
  73 #include <asm/io.h>
  74 #include <asm/bugs.h>
  75 #include <asm/setup.h>
  76 #include <asm/sections.h>
  77 #include <asm/cacheflush.h>
  78
  79 #ifdef CONFIG_X86_LOCAL_APIC
  80 #include <asm/smp.h>
  81 #endif
  82
  83 static int kernel_init(void *);
  84
  85 extern void init_IRQ(void);
  86 extern void fork_init(unsigned long);
  87 extern void mca_init(void);
  88 extern void sbus_init(void);
  89 extern void prio_tree_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 void __init __weak thread_info_cache_init(void)
 446 {
 447 }
 448
 449 /*
 450  * Set up kernel memory allocators
 451  */
 452 static void __init mm_init(void)
 453 {
 454         /*
 455          * page_cgroup requires contiguous pages,
 456          * bigger than MAX_ORDER unless SPARSEMEM.
 457          */
 458         page_cgroup_init_flatmem();
 459         mem_init();
 460         kmem_cache_init();
 461         percpu_init_late();
 462         pgtable_cache_init();
 463         vmalloc_init();
 464 #ifdef CONFIG_X86
 465         if (efi_enabled)
 466                 efi_enter_virtual_mode();
 467 #endif
 468 }
 469
 470 asmlinkage void __init start_kernel(void)
 471 {
 472         char * command_line;
 473         extern const struct kernel_param __start___param[], __stop___param[];
 474
 475         /*
 476          * Need to run as early as possible, to initialize the
 477          * lockdep hash:
 478          */
 479         lockdep_init();
 480         smp_setup_processor_id();
 481         debug_objects_early_init();
 482
 483         /*
 484          * Set up the the initial canary ASAP:
 485          */
 486         boot_init_stack_canary();
 487
 488         cgroup_init_early();
 489
 490         local_irq_disable();
 491         early_boot_irqs_disabled = true;
 492
 493 /*
 494  * Interrupts are still disabled. Do necessary setups, then
 495  * enable them
 496  */
 497         tick_init();
 498         boot_cpu_init();
 499         page_address_init();
 500         printk(KERN_NOTICE "%s", linux_banner);
 501         setup_arch(&command_line);
 502         mm_init_owner(&init_mm, &init_task);
 503         mm_init_cpumask(&init_mm);
 504         setup_command_line(command_line);
 505         setup_nr_cpu_ids();
 506         setup_per_cpu_areas();
 507         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 508
 509         build_all_zonelists(NULL, NULL);
 510         page_alloc_init();
 511
 512         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 513         parse_early_param();
 514         parse_args("Booting kernel", static_command_line, __start___param,
 515                    __stop___param - __start___param,
 516                    -1, -1, &unknown_bootoption);
 517
 518         jump_label_init();
 519
 520         /*
 521          * These use large bootmem allocations and must precede
 522          * kmem_cache_init()
 523          */
 524         setup_log_buf(0);
 525         pidhash_init();
 526         vfs_caches_init_early();
 527         sort_main_extable();
 528         trap_init();
 529         mm_init();
 530
 531         /*
 532          * Set up the scheduler prior starting any interrupts (such as the
 533          * timer interrupt). Full topology setup happens at smp_init()
 534          * time - but meanwhile we still have a functioning scheduler.
 535          */
 536         sched_init();
 537         /*
 538          * Disable preemption - early bootup scheduling is extremely
 539          * fragile until we cpu_idle() for the first time.
 540          */
 541         preempt_disable();
 542         if (!irqs_disabled()) {
 543                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 544                                 "enabled *very* early, fixing it\n");
 545                 local_irq_disable();
 546         }
 547         idr_init_cache();
 548         perf_event_init();
 549         rcu_init();
 550         radix_tree_init();
 551         /* init some links before init_ISA_irqs() */
 552         early_irq_init();
 553         init_IRQ();
 554         prio_tree_init();
 555         init_timers();
 556         hrtimers_init();
 557         softirq_init();
 558         timekeeping_init();
 559         time_init();
 560         profile_init();
 561         call_function_init();
 562         if (!irqs_disabled())
 563                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 564                                  "enabled early\n");
 565         early_boot_irqs_disabled = false;
 566         local_irq_enable();
 567
 568         kmem_cache_init_late();
 569
 570         /*
 571          * HACK ALERT! This is early. We're enabling the console before
 572          * we've done PCI setups etc, and console_init() must be aware of
 573          * this. But we do want output early, in case something goes wrong.
 574          */
 575         console_init();
 576         if (panic_later)
 577                 panic(panic_later, panic_param);
 578
 579         lockdep_info();
 580
 581         /*
 582          * Need to run this when irqs are enabled, because it wants
 583          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 584          * too:
 585          */
 586         locking_selftest();
 587
 588 #ifdef CONFIG_BLK_DEV_INITRD
 589         if (initrd_start && !initrd_below_start_ok &&
 590             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 591                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 592                     "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         thread_info_cache_init();
 610         cred_init();
 611         fork_init(totalram_pages);
 612         proc_caches_init();
 613         buffer_init();
 614         key_init();
 615         security_init();
 616         dbg_late_init();
 617         vfs_caches_init(totalram_pages);
 618         signals_init();
 619         /* rootfs populating might need page-writeback */
 620         page_writeback_init();
 621 #ifdef CONFIG_PROC_FS
 622         proc_root_init();
 623 #endif
 624         cgroup_init();
 625         cpuset_init();
 626         taskstats_init_early();
 627         delayacct_init();
 628
 629         check_bugs();
 630
 631         acpi_early_init(); /* before LAPIC and SMP init */
 632         sfi_init_late();
 633
 634         ftrace_init();
 635
 636         /* Do the rest non-__init'ed, we're now alive */
 637         rest_init();
 638 }
 639
 640 /* Call all constructor functions linked into the kernel. */
 641 static void __init do_ctors(void)
 642 {
 643 #ifdef CONFIG_CONSTRUCTORS
 644         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 645
 646         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 647                 (*fn)();
 648 #endif
 649 }
 650
 651 bool initcall_debug;
 652 core_param(initcall_debug, initcall_debug, bool, 0644);
 653
 654 static char msgbuf[64];
 655
 656 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 657 {
 658         ktime_t calltime, delta, rettime;
 659         unsigned long long duration;
 660         int ret;
 661
 662         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 663         calltime = ktime_get();
 664         ret = fn();
 665         rettime = ktime_get();
 666         delta = ktime_sub(rettime, calltime);
 667         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 668         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 669                 ret, duration);
 670
 671         return ret;
 672 }
 673
 674 int __init_or_module do_one_initcall(initcall_t fn)
 675 {
 676         int count = preempt_count();
 677         int ret;
 678
 679         if (initcall_debug)
 680                 ret = do_one_initcall_debug(fn);
 681         else
 682                 ret = fn();
 683
 684         msgbuf[0] = 0;
 685
 686         if (ret && ret != -ENODEV && initcall_debug)
 687                 sprintf(msgbuf, "error code %d ", ret);
 688
 689         if (preempt_count() != count) {
 690                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 691                 preempt_count() = count;
 692         }
 693         if (irqs_disabled()) {
 694                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 695                 local_irq_enable();
 696         }
 697         if (msgbuf[0]) {
 698                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 699         }
 700
 701         return ret;
 702 }
 703
 704
 705 extern initcall_t __initcall_start[];
 706 extern initcall_t __initcall0_start[];
 707 extern initcall_t __initcall1_start[];
 708 extern initcall_t __initcall2_start[];
 709 extern initcall_t __initcall3_start[];
 710 extern initcall_t __initcall4_start[];
 711 extern initcall_t __initcall5_start[];
 712 extern initcall_t __initcall6_start[];
 713 extern initcall_t __initcall7_start[];
 714 extern initcall_t __initcall_end[];
 715
 716 static initcall_t *initcall_levels[] __initdata = {
 717         __initcall0_start,
 718         __initcall1_start,
 719         __initcall2_start,
 720         __initcall3_start,
 721         __initcall4_start,
 722         __initcall5_start,
 723         __initcall6_start,
 724         __initcall7_start,
 725         __initcall_end,
 726 };
 727
 728 /* Keep these in sync with initcalls in include/linux/init.h */
 729 static char *initcall_level_names[] __initdata = {
 730         "early",
 731         "core",
 732         "postcore",
 733         "arch",
 734         "subsys",
 735         "fs",
 736         "device",
 737         "late",
 738 };
 739
 740 static void __init do_initcall_level(int level)
 741 {
 742         extern const struct kernel_param __start___param[], __stop___param[];
 743         initcall_t *fn;
 744
 745         strcpy(static_command_line, saved_command_line);
 746         parse_args(initcall_level_names[level],
 747                    static_command_line, __start___param,
 748                    __stop___param - __start___param,
 749                    level, level,
 750                    &repair_env_string);
 751
 752         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 753                 do_one_initcall(*fn);
 754 }
 755
 756 static void __init do_initcalls(void)
 757 {
 758         int level;
 759
 760         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 761                 do_initcall_level(level);
 762 }
 763
 764 /*
 765  * Ok, the machine is now initialized. None of the devices
 766  * have been touched yet, but the CPU subsystem is up and
 767  * running, and memory and process management works.
 768  *
 769  * Now we can finally start doing some real work..
 770  */
 771 static void __init do_basic_setup(void)
 772 {
 773         cpuset_init_smp();
 774         usermodehelper_init();
 775         shmem_init();
 776         driver_init();
 777         init_irq_proc();
 778         do_ctors();
 779         usermodehelper_enable();
 780         do_initcalls();
 781 }
 782
 783 static void __init do_pre_smp_initcalls(void)
 784 {
 785         initcall_t *fn;
 786
 787         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 788                 do_one_initcall(*fn);
 789 }
 790
 791 static void run_init_process(const char *init_filename)
 792 {
 793         argv_init[0] = init_filename;
 794         kernel_execve(init_filename, argv_init, envp_init);
 795 }
 796
 797 /* This is a non __init function. Force it to be noinline otherwise gcc
 798  * makes it inline to init() and it becomes part of init.text section
 799  */
 800 static noinline int init_post(void)
 801 {
 802         /* need to finish all async __init code before freeing the memory */
 803         async_synchronize_full();
 804         free_initmem();
 805         mark_rodata_ro();
 806         system_state = SYSTEM_RUNNING;
 807         numa_default_policy();
 808
 809         current->signal->flags |= SIGNAL_UNKILLABLE;
 810         flush_delayed_fput();
 811
 812         if (ramdisk_execute_command) {
 813                 run_init_process(ramdisk_execute_command);
 814                 printk(KERN_WARNING "Failed to execute %s\n",
 815                                 ramdisk_execute_command);
 816         }
 817
 818         /*
 819          * We try each of these until one succeeds.
 820          *
 821          * The Bourne shell can be used instead of init if we are
 822          * trying to recover a really broken machine.
 823          */
 824         if (execute_command) {
 825                 run_init_process(execute_command);
 826                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 827                                         "defaults...\n", execute_command);
 828         }
 829         run_init_process("/sbin/init");
 830         run_init_process("/etc/init");
 831         run_init_process("/bin/init");
 832         run_init_process("/bin/sh");
 833
 834         panic("No init found.  Try passing init= option to kernel. "
 835               "See Linux Documentation/init.txt for guidance.");
 836 }
 837
 838 static int __init kernel_init(void * unused)
 839 {
 840         /*
 841          * Wait until kthreadd is all set-up.
 842          */
 843         wait_for_completion(&kthreadd_done);
 844
 845         /* Now the scheduler is fully set up and can do blocking allocations */
 846         gfp_allowed_mask = __GFP_BITS_MASK;
 847
 848         /*
 849          * init can allocate pages on any node
 850          */
 851         set_mems_allowed(node_states[N_HIGH_MEMORY]);
 852         /*
 853          * init can run on any cpu.
 854          */
 855         set_cpus_allowed_ptr(current, cpu_all_mask);
 856
 857         cad_pid = task_pid(current);
 858
 859         smp_prepare_cpus(setup_max_cpus);
 860
 861         do_pre_smp_initcalls();
 862         lockup_detector_init();
 863
 864         smp_init();
 865         sched_init_smp();
 866
 867         do_basic_setup();
 868
 869         /* Open the /dev/console on the rootfs, this should never fail */
 870         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 871                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 872
 873         (void) sys_dup(0);
 874         (void) sys_dup(0);
 875         /*
 876          * check if there is an early userspace init.  If yes, let it do all
 877          * the work
 878          */
 879
 880         if (!ramdisk_execute_command)
 881                 ramdisk_execute_command = "/init";
 882
 883         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 884                 ramdisk_execute_command = NULL;
 885                 prepare_namespace();
 886         }
 887
 888         /*
 889          * Ok, we have completed the initial bootup, and
 890          * we're essentially up and running. Get rid of the
 891          * initmem segments and start the user-mode stuff..
 892          */
 893
 894         init_post();
 895         return 0;
 896 }