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/string.h>
  18 #include <linux/ctype.h>
  19 #include <linux/delay.h>
  20 #include <linux/utsname.h>
  21 #include <linux/ioport.h>
  22 #include <linux/init.h>
  23 #include <linux/smp_lock.h>
  24 #include <linux/initrd.h>
  25 #include <linux/hdreg.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/tty.h>
  28 #include <linux/gfp.h>
  29 #include <linux/percpu.h>
  30 #include <linux/kmod.h>
  31 #include <linux/kernel_stat.h>
  32 #include <linux/start_kernel.h>
  33 #include <linux/security.h>
  34 #include <linux/workqueue.h>
  35 #include <linux/profile.h>
  36 #include <linux/rcupdate.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/kallsyms.h>
  39 #include <linux/writeback.h>
  40 #include <linux/cpu.h>
  41 #include <linux/cpuset.h>
  42 #include <linux/cgroup.h>
  43 #include <linux/efi.h>
  44 #include <linux/tick.h>
  45 #include <linux/interrupt.h>
  46 #include <linux/taskstats_kern.h>
  47 #include <linux/delayacct.h>
  48 #include <linux/unistd.h>
  49 #include <linux/rmap.h>
  50 #include <linux/mempolicy.h>
  51 #include <linux/key.h>
  52 #include <linux/unwind.h>
  53 #include <linux/buffer_head.h>
  54 #include <linux/debug_locks.h>
  55 #include <linux/lockdep.h>
  56 #include <linux/pid_namespace.h>
  57 #include <linux/device.h>
  58 #include <linux/kthread.h>
  59
  60 #include <asm/io.h>
  61 #include <asm/bugs.h>
  62 #include <asm/setup.h>
  63 #include <asm/sections.h>
  64 #include <asm/cacheflush.h>
  65
  66 #ifdef CONFIG_X86_LOCAL_APIC
  67 #include <asm/smp.h>
  68 #endif
  69
  70 /*
  71  * This is one of the first .c files built. Error out early if we have compiler
  72  * trouble.
  73  */
  74
  75 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
  76 #warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.
  77 #endif
  78
  79 static int kernel_init(void *);
  80
  81 extern void init_IRQ(void);
  82 extern void fork_init(unsigned long);
  83 extern void mca_init(void);
  84 extern void sbus_init(void);
  85 extern void signals_init(void);
  86 extern void pidhash_init(void);
  87 extern void pidmap_init(void);
  88 extern void prio_tree_init(void);
  89 extern void radix_tree_init(void);
  90 extern void free_initmem(void);
  91 #ifdef  CONFIG_ACPI
  92 extern void acpi_early_init(void);
  93 #else
  94 static inline void acpi_early_init(void) { }
  95 #endif
  96 #ifndef CONFIG_DEBUG_RODATA
  97 static inline void mark_rodata_ro(void) { }
  98 #endif
  99
 100 #ifdef CONFIG_TC
 101 extern void tc_init(void);
 102 #endif
 103
 104 enum system_states system_state;
 105 EXPORT_SYMBOL(system_state);
 106
 107 /*
 108  * Boot command-line arguments
 109  */
 110 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 111 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 112
 113 extern void time_init(void);
 114 /* Default late time init is NULL. archs can override this later. */
 115 void (*late_time_init)(void);
 116 extern void softirq_init(void);
 117
 118 /* Untouched command line saved by arch-specific code. */
 119 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 120 /* Untouched saved command line (eg. for /proc) */
 121 char *saved_command_line;
 122 /* Command line for parameter parsing */
 123 static char *static_command_line;
 124
 125 static char *execute_command;
 126 static char *ramdisk_execute_command;
 127
 128 #ifdef CONFIG_SMP
 129 /* Setup configured maximum number of CPUs to activate */
 130 static unsigned int __initdata max_cpus = NR_CPUS;
 131
 132 /*
 133  * Setup routine for controlling SMP activation
 134  *
 135  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 136  * activation entirely (the MPS table probe still happens, though).
 137  *
 138  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 139  * greater than 0, limits the maximum number of CPUs activated in
 140  * SMP mode to <NUM>.
 141  */
 142 #ifndef CONFIG_X86_IO_APIC
 143 static inline void disable_ioapic_setup(void) {};
 144 #endif
 145
 146 static int __init nosmp(char *str)
 147 {
 148         max_cpus = 0;
 149         disable_ioapic_setup();
 150         return 0;
 151 }
 152
 153 early_param("nosmp", nosmp);
 154
 155 static int __init maxcpus(char *str)
 156 {
 157         get_option(&str, &max_cpus);
 158         if (max_cpus == 0)
 159                 disable_ioapic_setup();
 160
 161         return 0;
 162 }
 163
 164 early_param("maxcpus", maxcpus);
 165 #else
 166 #define max_cpus NR_CPUS
 167 #endif
 168
 169 /*
 170  * If set, this is an indication to the drivers that reset the underlying
 171  * device before going ahead with the initialization otherwise driver might
 172  * rely on the BIOS and skip the reset operation.
 173  *
 174  * This is useful if kernel is booting in an unreliable environment.
 175  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 176  * skipped and devices will be in unknown state.
 177  */
 178 unsigned int reset_devices;
 179 EXPORT_SYMBOL(reset_devices);
 180
 181 static int __init set_reset_devices(char *str)
 182 {
 183         reset_devices = 1;
 184         return 1;
 185 }
 186
 187 __setup("reset_devices", set_reset_devices);
 188
 189 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 190 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 191 static const char *panic_later, *panic_param;
 192
 193 extern struct obs_kernel_param __setup_start[], __setup_end[];
 194
 195 static int __init obsolete_checksetup(char *line)
 196 {
 197         struct obs_kernel_param *p;
 198         int had_early_param = 0;
 199
 200         p = __setup_start;
 201         do {
 202                 int n = strlen(p->str);
 203                 if (!strncmp(line, p->str, n)) {
 204                         if (p->early) {
 205                                 /* Already done in parse_early_param?
 206                                  * (Needs exact match on param part).
 207                                  * Keep iterating, as we can have early
 208                                  * params and __setups of same names 8( */
 209                                 if (line[n] == '\0' || line[n] == '=')
 210                                         had_early_param = 1;
 211                         } else if (!p->setup_func) {
 212                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 213                                        " ignored\n", p->str);
 214                                 return 1;
 215                         } else if (p->setup_func(line + n))
 216                                 return 1;
 217                 }
 218                 p++;
 219         } while (p < __setup_end);
 220
 221         return had_early_param;
 222 }
 223
 224 /*
 225  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 226  * still work even if initially too large, it will just take slightly longer
 227  */
 228 unsigned long loops_per_jiffy = (1<<12);
 229
 230 EXPORT_SYMBOL(loops_per_jiffy);
 231
 232 static int __init debug_kernel(char *str)
 233 {
 234         if (*str)
 235                 return 0;
 236         console_loglevel = 10;
 237         return 1;
 238 }
 239
 240 static int __init quiet_kernel(char *str)
 241 {
 242         if (*str)
 243                 return 0;
 244         console_loglevel = 4;
 245         return 1;
 246 }
 247
 248 __setup("debug", debug_kernel);
 249 __setup("quiet", quiet_kernel);
 250
 251 static int __init loglevel(char *str)
 252 {
 253         get_option(&str, &console_loglevel);
 254         return 1;
 255 }
 256
 257 __setup("loglevel=", loglevel);
 258
 259 /*
 260  * Unknown boot options get handed to init, unless they look like
 261  * failed parameters
 262  */
 263 static int __init unknown_bootoption(char *param, char *val)
 264 {
 265         /* Change NUL term back to "=", to make "param" the whole string. */
 266         if (val) {
 267                 /* param=val or param="val"? */
 268                 if (val == param+strlen(param)+1)
 269                         val[-1] = '=';
 270                 else if (val == param+strlen(param)+2) {
 271                         val[-2] = '=';
 272                         memmove(val-1, val, strlen(val)+1);
 273                         val--;
 274                 } else
 275                         BUG();
 276         }
 277
 278         /* Handle obsolete-style parameters */
 279         if (obsolete_checksetup(param))
 280                 return 0;
 281
 282         /*
 283          * Preemptive maintenance for "why didn't my misspelled command
 284          * line work?"
 285          */
 286         if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 287                 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 288                 return 0;
 289         }
 290
 291         if (panic_later)
 292                 return 0;
 293
 294         if (val) {
 295                 /* Environment option */
 296                 unsigned int i;
 297                 for (i = 0; envp_init[i]; i++) {
 298                         if (i == MAX_INIT_ENVS) {
 299                                 panic_later = "Too many boot env vars at `%s'";
 300                                 panic_param = param;
 301                         }
 302                         if (!strncmp(param, envp_init[i], val - param))
 303                                 break;
 304                 }
 305                 envp_init[i] = param;
 306         } else {
 307                 /* Command line option */
 308                 unsigned int i;
 309                 for (i = 0; argv_init[i]; i++) {
 310                         if (i == MAX_INIT_ARGS) {
 311                                 panic_later = "Too many boot init vars at `%s'";
 312                                 panic_param = param;
 313                         }
 314                 }
 315                 argv_init[i] = param;
 316         }
 317         return 0;
 318 }
 319
 320 static int __init init_setup(char *str)
 321 {
 322         unsigned int i;
 323
 324         execute_command = str;
 325         /*
 326          * In case LILO is going to boot us with default command line,
 327          * it prepends "auto" before the whole cmdline which makes
 328          * the shell think it should execute a script with such name.
 329          * So we ignore all arguments entered _before_ init=... [MJ]
 330          */
 331         for (i = 1; i < MAX_INIT_ARGS; i++)
 332                 argv_init[i] = NULL;
 333         return 1;
 334 }
 335 __setup("init=", init_setup);
 336
 337 static int __init rdinit_setup(char *str)
 338 {
 339         unsigned int i;
 340
 341         ramdisk_execute_command = str;
 342         /* See "auto" comment in init_setup */
 343         for (i = 1; i < MAX_INIT_ARGS; i++)
 344                 argv_init[i] = NULL;
 345         return 1;
 346 }
 347 __setup("rdinit=", rdinit_setup);
 348
 349 #ifndef CONFIG_SMP
 350
 351 #ifdef CONFIG_X86_LOCAL_APIC
 352 static void __init smp_init(void)
 353 {
 354         APIC_init_uniprocessor();
 355 }
 356 #else
 357 #define smp_init()      do { } while (0)
 358 #endif
 359
 360 static inline void setup_per_cpu_areas(void) { }
 361 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 362
 363 #else
 364
 365 #ifdef __GENERIC_PER_CPU
 366 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 367
 368 EXPORT_SYMBOL(__per_cpu_offset);
 369
 370 static void __init setup_per_cpu_areas(void)
 371 {
 372         unsigned long size, i;
 373         char *ptr;
 374         unsigned long nr_possible_cpus = num_possible_cpus();
 375
 376         /* Copy section for each CPU (we discard the original) */
 377         size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
 378         ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 379
 380         for_each_possible_cpu(i) {
 381                 __per_cpu_offset[i] = ptr - __per_cpu_start;
 382                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 383                 ptr += size;
 384         }
 385 }
 386 #endif /* !__GENERIC_PER_CPU */
 387
 388 /* Called by boot processor to activate the rest. */
 389 static void __init smp_init(void)
 390 {
 391         unsigned int cpu;
 392
 393         /* FIXME: This should be done in userspace --RR */
 394         for_each_present_cpu(cpu) {
 395                 if (num_online_cpus() >= max_cpus)
 396                         break;
 397                 if (!cpu_online(cpu))
 398                         cpu_up(cpu);
 399         }
 400
 401         /* Any cleanup work */
 402         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 403         smp_cpus_done(max_cpus);
 404 }
 405
 406 #endif
 407
 408 /*
 409  * We need to store the untouched command line for future reference.
 410  * We also need to store the touched command line since the parameter
 411  * parsing is performed in place, and we should allow a component to
 412  * store reference of name/value for future reference.
 413  */
 414 static void __init setup_command_line(char *command_line)
 415 {
 416         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 417         static_command_line = alloc_bootmem(strlen (command_line)+1);
 418         strcpy (saved_command_line, boot_command_line);
 419         strcpy (static_command_line, command_line);
 420 }
 421
 422 /*
 423  * We need to finalize in a non-__init function or else race conditions
 424  * between the root thread and the init thread may cause start_kernel to
 425  * be reaped by free_initmem before the root thread has proceeded to
 426  * cpu_idle.
 427  *
 428  * gcc-3.4 accidentally inlines this function, so use noinline.
 429  */
 430
 431 static void noinline __init_refok rest_init(void)
 432         __releases(kernel_lock)
 433 {
 434         int pid;
 435
 436         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 437         numa_default_policy();
 438         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 439         kthreadd_task = find_task_by_pid(pid);
 440         unlock_kernel();
 441
 442         /*
 443          * The boot idle thread must execute schedule()
 444          * at least once to get things moving:
 445          */
 446         init_idle_bootup_task(current);
 447         preempt_enable_no_resched();
 448         schedule();
 449         preempt_disable();
 450
 451         /* Call into cpu_idle with preempt disabled */
 452         cpu_idle();
 453 }
 454
 455 /* Check for early params. */
 456 static int __init do_early_param(char *param, char *val)
 457 {
 458         struct obs_kernel_param *p;
 459
 460         for (p = __setup_start; p < __setup_end; p++) {
 461                 if ((p->early && strcmp(param, p->str) == 0) ||
 462                     (strcmp(param, "console") == 0 &&
 463                      strcmp(p->str, "earlycon") == 0)
 464                 ) {
 465                         if (p->setup_func(val) != 0)
 466                                 printk(KERN_WARNING
 467                                        "Malformed early option '%s'\n", param);
 468                 }
 469         }
 470         /* We accept everything at this stage. */
 471         return 0;
 472 }
 473
 474 /* Arch code calls this early on, or if not, just before other parsing. */
 475 void __init parse_early_param(void)
 476 {
 477         static __initdata int done = 0;
 478         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 479
 480         if (done)
 481                 return;
 482
 483         /* All fall through to do_early_param. */
 484         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 485         parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 486         done = 1;
 487 }
 488
 489 /*
 490  *      Activate the first processor.
 491  */
 492
 493 static void __init boot_cpu_init(void)
 494 {
 495         int cpu = smp_processor_id();
 496         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 497         cpu_set(cpu, cpu_online_map);
 498         cpu_set(cpu, cpu_present_map);
 499         cpu_set(cpu, cpu_possible_map);
 500 }
 501
 502 void __init __attribute__((weak)) smp_setup_processor_id(void)
 503 {
 504 }
 505
 506 asmlinkage void __init start_kernel(void)
 507 {
 508         char * command_line;
 509         extern struct kernel_param __start___param[], __stop___param[];
 510
 511         smp_setup_processor_id();
 512
 513         /*
 514          * Need to run as early as possible, to initialize the
 515          * lockdep hash:
 516          */
 517         unwind_init();
 518         lockdep_init();
 519         cgroup_init_early();
 520
 521         local_irq_disable();
 522         early_boot_irqs_off();
 523         early_init_irq_lock_class();
 524
 525 /*
 526  * Interrupts are still disabled. Do necessary setups, then
 527  * enable them
 528  */
 529         lock_kernel();
 530         tick_init();
 531         boot_cpu_init();
 532         page_address_init();
 533         printk(KERN_NOTICE);
 534         printk(linux_banner);
 535         setup_arch(&command_line);
 536         setup_command_line(command_line);
 537         unwind_setup();
 538         setup_per_cpu_areas();
 539         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 540
 541         /*
 542          * Set up the scheduler prior starting any interrupts (such as the
 543          * timer interrupt). Full topology setup happens at smp_init()
 544          * time - but meanwhile we still have a functioning scheduler.
 545          */
 546         sched_init();
 547         /*
 548          * Disable preemption - early bootup scheduling is extremely
 549          * fragile until we cpu_idle() for the first time.
 550          */
 551         preempt_disable();
 552         build_all_zonelists();
 553         page_alloc_init();
 554         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 555         parse_early_param();
 556         parse_args("Booting kernel", static_command_line, __start___param,
 557                    __stop___param - __start___param,
 558                    &unknown_bootoption);
 559         if (!irqs_disabled()) {
 560                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 561                                 "enabled *very* early, fixing it\n");
 562                 local_irq_disable();
 563         }
 564         sort_main_extable();
 565         trap_init();
 566         rcu_init();
 567         init_IRQ();
 568         pidhash_init();
 569         init_timers();
 570         hrtimers_init();
 571         softirq_init();
 572         timekeeping_init();
 573         time_init();
 574         profile_init();
 575         if (!irqs_disabled())
 576                 printk("start_kernel(): bug: interrupts were enabled early\n");
 577         early_boot_irqs_on();
 578         local_irq_enable();
 579
 580         /*
 581          * HACK ALERT! This is early. We're enabling the console before
 582          * we've done PCI setups etc, and console_init() must be aware of
 583          * this. But we do want output early, in case something goes wrong.
 584          */
 585         console_init();
 586         if (panic_later)
 587                 panic(panic_later, panic_param);
 588
 589         lockdep_info();
 590
 591         /*
 592          * Need to run this when irqs are enabled, because it wants
 593          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 594          * too:
 595          */
 596         locking_selftest();
 597
 598 #ifdef CONFIG_BLK_DEV_INITRD
 599         if (initrd_start && !initrd_below_start_ok &&
 600                         initrd_start < min_low_pfn << PAGE_SHIFT) {
 601                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 602                     "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 603                 initrd_start = 0;
 604         }
 605 #endif
 606         vfs_caches_init_early();
 607         cpuset_init_early();
 608         mem_init();
 609         kmem_cache_init();
 610         setup_per_cpu_pageset();
 611         numa_policy_init();
 612         if (late_time_init)
 613                 late_time_init();
 614         calibrate_delay();
 615         pidmap_init();
 616         pgtable_cache_init();
 617         prio_tree_init();
 618         anon_vma_init();
 619 #ifdef CONFIG_X86
 620         if (efi_enabled)
 621                 efi_enter_virtual_mode();
 622 #endif
 623         fork_init(num_physpages);
 624         proc_caches_init();
 625         buffer_init();
 626         unnamed_dev_init();
 627         key_init();
 628         security_init();
 629         vfs_caches_init(num_physpages);
 630         radix_tree_init();
 631         signals_init();
 632         /* rootfs populating might need page-writeback */
 633         page_writeback_init();
 634 #ifdef CONFIG_PROC_FS
 635         proc_root_init();
 636 #endif
 637         cgroup_init();
 638         cpuset_init();
 639         taskstats_init_early();
 640         delayacct_init();
 641
 642         check_bugs();
 643
 644         acpi_early_init(); /* before LAPIC and SMP init */
 645
 646         /* Do the rest non-__init'ed, we're now alive */
 647         rest_init();
 648 }
 649
 650 static int __initdata initcall_debug;
 651
 652 static int __init initcall_debug_setup(char *str)
 653 {
 654         initcall_debug = 1;
 655         return 1;
 656 }
 657 __setup("initcall_debug", initcall_debug_setup);
 658
 659 extern initcall_t __initcall_start[], __initcall_end[];
 660
 661 static void __init do_initcalls(void)
 662 {
 663         initcall_t *call;
 664         int count = preempt_count();
 665
 666         for (call = __initcall_start; call < __initcall_end; call++) {
 667                 ktime_t t0, t1, delta;
 668                 char *msg = NULL;
 669                 char msgbuf[40];
 670                 int result;
 671
 672                 if (initcall_debug) {
 673                         printk("Calling initcall 0x%p", *call);
 674                         print_fn_descriptor_symbol(": %s()",
 675                                         (unsigned long) *call);
 676                         printk("\n");
 677                         t0 = ktime_get();
 678                 }
 679
 680                 result = (*call)();
 681
 682                 if (initcall_debug) {
 683                         t1 = ktime_get();
 684                         delta = ktime_sub(t1, t0);
 685
 686                         printk("initcall 0x%p", *call);
 687                         print_fn_descriptor_symbol(": %s()",
 688                                         (unsigned long) *call);
 689                         printk(" returned %d.\n", result);
 690
 691                         printk("initcall 0x%p ran for %Ld msecs: ",
 692                                 *call, (unsigned long long)delta.tv64 >> 20);
 693                         print_fn_descriptor_symbol("%s()\n",
 694                                 (unsigned long) *call);
 695                 }
 696
 697                 if (result && result != -ENODEV && initcall_debug) {
 698                         sprintf(msgbuf, "error code %d", result);
 699                         msg = msgbuf;
 700                 }
 701                 if (preempt_count() != count) {
 702                         msg = "preemption imbalance";
 703                         preempt_count() = count;
 704                 }
 705                 if (irqs_disabled()) {
 706                         msg = "disabled interrupts";
 707                         local_irq_enable();
 708                 }
 709                 if (msg) {
 710                         printk(KERN_WARNING "initcall at 0x%p", *call);
 711                         print_fn_descriptor_symbol(": %s()",
 712                                         (unsigned long) *call);
 713                         printk(": returned with %s\n", msg);
 714                 }
 715         }
 716
 717         /* Make sure there is no pending stuff from the initcall sequence */
 718         flush_scheduled_work();
 719 }
 720
 721 /*
 722  * Ok, the machine is now initialized. None of the devices
 723  * have been touched yet, but the CPU subsystem is up and
 724  * running, and memory and process management works.
 725  *
 726  * Now we can finally start doing some real work..
 727  */
 728 static void __init do_basic_setup(void)
 729 {
 730         /* drivers will send hotplug events */
 731         init_workqueues();
 732         usermodehelper_init();
 733         driver_init();
 734         init_irq_proc();
 735         do_initcalls();
 736 }
 737
 738 static int __initdata nosoftlockup;
 739
 740 static int __init nosoftlockup_setup(char *str)
 741 {
 742         nosoftlockup = 1;
 743         return 1;
 744 }
 745 __setup("nosoftlockup", nosoftlockup_setup);
 746
 747 static void __init do_pre_smp_initcalls(void)
 748 {
 749         extern int spawn_ksoftirqd(void);
 750 #ifdef CONFIG_SMP
 751         extern int migration_init(void);
 752
 753         migration_init();
 754 #endif
 755         spawn_ksoftirqd();
 756         if (!nosoftlockup)
 757                 spawn_softlockup_task();
 758 }
 759
 760 static void run_init_process(char *init_filename)
 761 {
 762         argv_init[0] = init_filename;
 763         kernel_execve(init_filename, argv_init, envp_init);
 764 }
 765
 766 /* This is a non __init function. Force it to be noinline otherwise gcc
 767  * makes it inline to init() and it becomes part of init.text section
 768  */
 769 static int noinline init_post(void)
 770 {
 771         free_initmem();
 772         unlock_kernel();
 773         mark_rodata_ro();
 774         system_state = SYSTEM_RUNNING;
 775         numa_default_policy();
 776
 777         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 778                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 779
 780         (void) sys_dup(0);
 781         (void) sys_dup(0);
 782
 783         if (ramdisk_execute_command) {
 784                 run_init_process(ramdisk_execute_command);
 785                 printk(KERN_WARNING "Failed to execute %s\n",
 786                                 ramdisk_execute_command);
 787         }
 788
 789         /*
 790          * We try each of these until one succeeds.
 791          *
 792          * The Bourne shell can be used instead of init if we are
 793          * trying to recover a really broken machine.
 794          */
 795         if (execute_command) {
 796                 run_init_process(execute_command);
 797                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 798                                         "defaults...\n", execute_command);
 799         }
 800         run_init_process("/sbin/init");
 801         run_init_process("/etc/init");
 802         run_init_process("/bin/init");
 803         run_init_process("/bin/sh");
 804
 805         panic("No init found.  Try passing init= option to kernel.");
 806 }
 807
 808 static int __init kernel_init(void * unused)
 809 {
 810         lock_kernel();
 811         /*
 812          * init can run on any cpu.
 813          */
 814         set_cpus_allowed(current, CPU_MASK_ALL);
 815         /*
 816          * Tell the world that we're going to be the grim
 817          * reaper of innocent orphaned children.
 818          *
 819          * We don't want people to have to make incorrect
 820          * assumptions about where in the task array this
 821          * can be found.
 822          */
 823         init_pid_ns.child_reaper = current;
 824
 825         __set_special_pids(1, 1);
 826         cad_pid = task_pid(current);
 827
 828         smp_prepare_cpus(max_cpus);
 829
 830         do_pre_smp_initcalls();
 831
 832         smp_init();
 833         sched_init_smp();
 834
 835         cpuset_init_smp();
 836
 837         do_basic_setup();
 838
 839         /*
 840          * check if there is an early userspace init.  If yes, let it do all
 841          * the work
 842          */
 843
 844         if (!ramdisk_execute_command)
 845                 ramdisk_execute_command = "/init";
 846
 847         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 848                 ramdisk_execute_command = NULL;
 849                 prepare_namespace();
 850         }
 851
 852         /*
 853          * Ok, we have completed the initial bootup, and
 854          * we're essentially up and running. Get rid of the
 855          * initmem segments and start the user-mode stuff..
 856          */
 857         init_post();
 858         return 0;
 859 }