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 #include <linux/blkdev.h>
  74 #include <linux/elevator.h>
  75
  76 #include <asm/io.h>
  77 #include <asm/bugs.h>
  78 #include <asm/setup.h>
  79 #include <asm/sections.h>
  80 #include <asm/cacheflush.h>
  81
  82 #ifdef CONFIG_X86_LOCAL_APIC
  83 #include <asm/smp.h>
  84 #endif
  85
  86 static int kernel_init(void *);
  87
  88 extern void init_IRQ(void);
  89 extern void fork_init(unsigned long);
  90 extern void mca_init(void);
  91 extern void sbus_init(void);
  92 extern void radix_tree_init(void);
  93 #ifndef CONFIG_DEBUG_RODATA
  94 static inline void mark_rodata_ro(void) { }
  95 #endif
  96
  97 #ifdef CONFIG_TC
  98 extern void tc_init(void);
  99 #endif
 100
 101 /*
 102  * Debug helper: via this flag we know that we are in 'early bootup code'
 103  * where only the boot processor is running with IRQ disabled.  This means
 104  * two things - IRQ must not be enabled before the flag is cleared and some
 105  * operations which are not allowed with IRQ disabled are allowed while the
 106  * flag is set.
 107  */
 108 bool early_boot_irqs_disabled __read_mostly;
 109
 110 enum system_states system_state __read_mostly;
 111 EXPORT_SYMBOL(system_state);
 112
 113 /*
 114  * Boot command-line arguments
 115  */
 116 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 117 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 118
 119 extern void time_init(void);
 120 /* Default late time init is NULL. archs can override this later. */
 121 void (*__initdata late_time_init)(void);
 122 extern void softirq_init(void);
 123
 124 /* Untouched command line saved by arch-specific code. */
 125 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 126 /* Untouched saved command line (eg. for /proc) */
 127 char *saved_command_line;
 128 /* Command line for parameter parsing */
 129 static char *static_command_line;
 130
 131 static char *execute_command;
 132 static char *ramdisk_execute_command;
 133
 134 /*
 135  * If set, this is an indication to the drivers that reset the underlying
 136  * device before going ahead with the initialization otherwise driver might
 137  * rely on the BIOS and skip the reset operation.
 138  *
 139  * This is useful if kernel is booting in an unreliable environment.
 140  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 141  * skipped and devices will be in unknown state.
 142  */
 143 unsigned int reset_devices;
 144 EXPORT_SYMBOL(reset_devices);
 145
 146 static int __init set_reset_devices(char *str)
 147 {
 148         reset_devices = 1;
 149         return 1;
 150 }
 151
 152 __setup("reset_devices", set_reset_devices);
 153
 154 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 155 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 156 static const char *panic_later, *panic_param;
 157
 158 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 159
 160 static int __init obsolete_checksetup(char *line)
 161 {
 162         const struct obs_kernel_param *p;
 163         int had_early_param = 0;
 164
 165         p = __setup_start;
 166         do {
 167                 int n = strlen(p->str);
 168                 if (parameqn(line, p->str, n)) {
 169                         if (p->early) {
 170                                 /* Already done in parse_early_param?
 171                                  * (Needs exact match on param part).
 172                                  * Keep iterating, as we can have early
 173                                  * params and __setups of same names 8( */
 174                                 if (line[n] == '\0' || line[n] == '=')
 175                                         had_early_param = 1;
 176                         } else if (!p->setup_func) {
 177                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 178                                        " ignored\n", p->str);
 179                                 return 1;
 180                         } else if (p->setup_func(line + n))
 181                                 return 1;
 182                 }
 183                 p++;
 184         } while (p < __setup_end);
 185
 186         return had_early_param;
 187 }
 188
 189 /*
 190  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 191  * still work even if initially too large, it will just take slightly longer
 192  */
 193 unsigned long loops_per_jiffy = (1<<12);
 194
 195 EXPORT_SYMBOL(loops_per_jiffy);
 196
 197 static int __init debug_kernel(char *str)
 198 {
 199         console_loglevel = 10;
 200         return 0;
 201 }
 202
 203 static int __init quiet_kernel(char *str)
 204 {
 205         console_loglevel = 4;
 206         return 0;
 207 }
 208
 209 early_param("debug", debug_kernel);
 210 early_param("quiet", quiet_kernel);
 211
 212 static int __init loglevel(char *str)
 213 {
 214         int newlevel;
 215
 216         /*
 217          * Only update loglevel value when a correct setting was passed,
 218          * to prevent blind crashes (when loglevel being set to 0) that
 219          * are quite hard to debug
 220          */
 221         if (get_option(&str, &newlevel)) {
 222                 console_loglevel = newlevel;
 223                 return 0;
 224         }
 225
 226         return -EINVAL;
 227 }
 228
 229 early_param("loglevel", loglevel);
 230
 231 /* Change NUL term back to "=", to make "param" the whole string. */
 232 static int __init repair_env_string(char *param, char *val, const char *unused)
 233 {
 234         if (val) {
 235                 /* param=val or param="val"? */
 236                 if (val == param+strlen(param)+1)
 237                         val[-1] = '=';
 238                 else if (val == param+strlen(param)+2) {
 239                         val[-2] = '=';
 240                         memmove(val-1, val, strlen(val)+1);
 241                         val--;
 242                 } else
 243                         BUG();
 244         }
 245         return 0;
 246 }
 247
 248 /*
 249  * Unknown boot options get handed to init, unless they look like
 250  * unused parameters (modprobe will find them in /proc/cmdline).
 251  */
 252 static int __init unknown_bootoption(char *param, char *val, const char *unused)
 253 {
 254         repair_env_string(param, val, unused);
 255
 256         /* Handle obsolete-style parameters */
 257         if (obsolete_checksetup(param))
 258                 return 0;
 259
 260         /* Unused module parameter. */
 261         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 262                 return 0;
 263
 264         if (panic_later)
 265                 return 0;
 266
 267         if (val) {
 268                 /* Environment option */
 269                 unsigned int i;
 270                 for (i = 0; envp_init[i]; i++) {
 271                         if (i == MAX_INIT_ENVS) {
 272                                 panic_later = "Too many boot env vars at `%s'";
 273                                 panic_param = param;
 274                         }
 275                         if (!strncmp(param, envp_init[i], val - param))
 276                                 break;
 277                 }
 278                 envp_init[i] = param;
 279         } else {
 280                 /* Command line option */
 281                 unsigned int i;
 282                 for (i = 0; argv_init[i]; i++) {
 283                         if (i == MAX_INIT_ARGS) {
 284                                 panic_later = "Too many boot init vars at `%s'";
 285                                 panic_param = param;
 286                         }
 287                 }
 288                 argv_init[i] = param;
 289         }
 290         return 0;
 291 }
 292
 293 static int __init init_setup(char *str)
 294 {
 295         unsigned int i;
 296
 297         execute_command = str;
 298         /*
 299          * In case LILO is going to boot us with default command line,
 300          * it prepends "auto" before the whole cmdline which makes
 301          * the shell think it should execute a script with such name.
 302          * So we ignore all arguments entered _before_ init=... [MJ]
 303          */
 304         for (i = 1; i < MAX_INIT_ARGS; i++)
 305                 argv_init[i] = NULL;
 306         return 1;
 307 }
 308 __setup("init=", init_setup);
 309
 310 static int __init rdinit_setup(char *str)
 311 {
 312         unsigned int i;
 313
 314         ramdisk_execute_command = str;
 315         /* See "auto" comment in init_setup */
 316         for (i = 1; i < MAX_INIT_ARGS; i++)
 317                 argv_init[i] = NULL;
 318         return 1;
 319 }
 320 __setup("rdinit=", rdinit_setup);
 321
 322 #ifndef CONFIG_SMP
 323 static const unsigned int setup_max_cpus = NR_CPUS;
 324 #ifdef CONFIG_X86_LOCAL_APIC
 325 static void __init smp_init(void)
 326 {
 327         APIC_init_uniprocessor();
 328 }
 329 #else
 330 #define smp_init()      do { } while (0)
 331 #endif
 332
 333 static inline void setup_nr_cpu_ids(void) { }
 334 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 335 #endif
 336
 337 /*
 338  * We need to store the untouched command line for future reference.
 339  * We also need to store the touched command line since the parameter
 340  * parsing is performed in place, and we should allow a component to
 341  * store reference of name/value for future reference.
 342  */
 343 static void __init setup_command_line(char *command_line)
 344 {
 345         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 346         static_command_line = alloc_bootmem(strlen (command_line)+1);
 347         strcpy (saved_command_line, boot_command_line);
 348         strcpy (static_command_line, command_line);
 349 }
 350
 351 /*
 352  * We need to finalize in a non-__init function or else race conditions
 353  * between the root thread and the init thread may cause start_kernel to
 354  * be reaped by free_initmem before the root thread has proceeded to
 355  * cpu_idle.
 356  *
 357  * gcc-3.4 accidentally inlines this function, so use noinline.
 358  */
 359
 360 static __initdata DECLARE_COMPLETION(kthreadd_done);
 361
 362 static noinline void __init_refok rest_init(void)
 363 {
 364         int pid;
 365
 366         rcu_scheduler_starting();
 367         /*
 368          * We need to spawn init first so that it obtains pid 1, however
 369          * the init task will end up wanting to create kthreads, which, if
 370          * we schedule it before we create kthreadd, will OOPS.
 371          */
 372         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 373         numa_default_policy();
 374         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 375         rcu_read_lock();
 376         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 377         rcu_read_unlock();
 378         complete(&kthreadd_done);
 379
 380         /*
 381          * The boot idle thread must execute schedule()
 382          * at least once to get things moving:
 383          */
 384         init_idle_bootup_task(current);
 385         schedule_preempt_disabled();
 386         /* Call into cpu_idle with preempt disabled */
 387         cpu_idle();
 388 }
 389
 390 /* Check for early params. */
 391 static int __init do_early_param(char *param, char *val, const char *unused)
 392 {
 393         const struct obs_kernel_param *p;
 394
 395         for (p = __setup_start; p < __setup_end; p++) {
 396                 if ((p->early && parameq(param, p->str)) ||
 397                     (strcmp(param, "console") == 0 &&
 398                      strcmp(p->str, "earlycon") == 0)
 399                 ) {
 400                         if (p->setup_func(val) != 0)
 401                                 printk(KERN_WARNING
 402                                        "Malformed early option '%s'\n", param);
 403                 }
 404         }
 405         /* We accept everything at this stage. */
 406         return 0;
 407 }
 408
 409 void __init parse_early_options(char *cmdline)
 410 {
 411         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
 412 }
 413
 414 /* Arch code calls this early on, or if not, just before other parsing. */
 415 void __init parse_early_param(void)
 416 {
 417         static __initdata int done = 0;
 418         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 419
 420         if (done)
 421                 return;
 422
 423         /* All fall through to do_early_param. */
 424         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 425         parse_early_options(tmp_cmdline);
 426         done = 1;
 427 }
 428
 429 /*
 430  *      Activate the first processor.
 431  */
 432
 433 static void __init boot_cpu_init(void)
 434 {
 435         int cpu = smp_processor_id();
 436         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 437         set_cpu_online(cpu, true);
 438         set_cpu_active(cpu, true);
 439         set_cpu_present(cpu, true);
 440         set_cpu_possible(cpu, true);
 441 }
 442
 443 void __init __weak smp_setup_processor_id(void)
 444 {
 445 }
 446
 447 # if THREAD_SIZE >= PAGE_SIZE
 448 void __init __weak thread_info_cache_init(void)
 449 {
 450 }
 451 #endif
 452
 453 /*
 454  * Set up kernel memory allocators
 455  */
 456 static void __init mm_init(void)
 457 {
 458         /*
 459          * page_cgroup requires contiguous pages,
 460          * bigger than MAX_ORDER unless SPARSEMEM.
 461          */
 462         page_cgroup_init_flatmem();
 463         mem_init();
 464         kmem_cache_init();
 465         percpu_init_late();
 466         pgtable_cache_init();
 467         vmalloc_init();
 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         init_timers();
 555         hrtimers_init();
 556         softirq_init();
 557         timekeeping_init();
 558         time_init();
 559         profile_init();
 560         call_function_init();
 561         if (!irqs_disabled())
 562                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 563                                  "enabled early\n");
 564         early_boot_irqs_disabled = false;
 565         local_irq_enable();
 566
 567         kmem_cache_init_late();
 568
 569         /*
 570          * HACK ALERT! This is early. We're enabling the console before
 571          * we've done PCI setups etc, and console_init() must be aware of
 572          * this. But we do want output early, in case something goes wrong.
 573          */
 574         console_init();
 575         if (panic_later)
 576                 panic(panic_later, panic_param);
 577
 578         lockdep_info();
 579
 580         /*
 581          * Need to run this when irqs are enabled, because it wants
 582          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 583          * too:
 584          */
 585         locking_selftest();
 586
 587 #ifdef CONFIG_BLK_DEV_INITRD
 588         if (initrd_start && !initrd_below_start_ok &&
 589             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 590                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 591                     "disabling it.\n",
 592                     page_to_pfn(virt_to_page((void *)initrd_start)),
 593                     min_low_pfn);
 594                 initrd_start = 0;
 595         }
 596 #endif
 597         page_cgroup_init();
 598         debug_objects_mem_init();
 599         kmemleak_init();
 600         setup_per_cpu_pageset();
 601         numa_policy_init();
 602         if (late_time_init)
 603                 late_time_init();
 604         sched_clock_init();
 605         calibrate_delay();
 606         pidmap_init();
 607         anon_vma_init();
 608 #ifdef CONFIG_X86
 609         if (efi_enabled(EFI_RUNTIME_SERVICES))
 610                 efi_enter_virtual_mode();
 611 #endif
 612         thread_info_cache_init();
 613         cred_init();
 614         fork_init(totalram_pages);
 615         proc_caches_init();
 616         buffer_init();
 617         key_init();
 618         security_init();
 619         dbg_late_init();
 620         vfs_caches_init(totalram_pages);
 621         signals_init();
 622         /* rootfs populating might need page-writeback */
 623         page_writeback_init();
 624 #ifdef CONFIG_PROC_FS
 625         proc_root_init();
 626 #endif
 627         cgroup_init();
 628         cpuset_init();
 629         taskstats_init_early();
 630         delayacct_init();
 631
 632         check_bugs();
 633
 634         acpi_early_init(); /* before LAPIC and SMP init */
 635         sfi_init_late();
 636
 637         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
 638                 efi_late_init();
 639                 efi_free_boot_services();
 640         }
 641
 642         ftrace_init();
 643
 644         /* Do the rest non-__init'ed, we're now alive */
 645         rest_init();
 646 }
 647
 648 /* Call all constructor functions linked into the kernel. */
 649 static void __init do_ctors(void)
 650 {
 651 #ifdef CONFIG_CONSTRUCTORS
 652         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 653
 654         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 655                 (*fn)();
 656 #endif
 657 }
 658
 659 bool initcall_debug;
 660 core_param(initcall_debug, initcall_debug, bool, 0644);
 661
 662 static char msgbuf[64];
 663
 664 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 665 {
 666         ktime_t calltime, delta, rettime;
 667         unsigned long long duration;
 668         int ret;
 669
 670         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 671         calltime = ktime_get();
 672         ret = fn();
 673         rettime = ktime_get();
 674         delta = ktime_sub(rettime, calltime);
 675         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 676         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 677                 ret, duration);
 678
 679         return ret;
 680 }
 681
 682 int __init_or_module do_one_initcall(initcall_t fn)
 683 {
 684         int count = preempt_count();
 685         int ret;
 686
 687         if (initcall_debug)
 688                 ret = do_one_initcall_debug(fn);
 689         else
 690                 ret = fn();
 691
 692         msgbuf[0] = 0;
 693
 694         if (ret && ret != -ENODEV && initcall_debug)
 695                 sprintf(msgbuf, "error code %d ", ret);
 696
 697         if (preempt_count() != count) {
 698                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 699                 preempt_count() = count;
 700         }
 701         if (irqs_disabled()) {
 702                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 703                 local_irq_enable();
 704         }
 705         if (msgbuf[0]) {
 706                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 707         }
 708
 709         return ret;
 710 }
 711
 712
 713 extern initcall_t __initcall_start[];
 714 extern initcall_t __initcall0_start[];
 715 extern initcall_t __initcall1_start[];
 716 extern initcall_t __initcall2_start[];
 717 extern initcall_t __initcall3_start[];
 718 extern initcall_t __initcall4_start[];
 719 extern initcall_t __initcall5_start[];
 720 extern initcall_t __initcall6_start[];
 721 extern initcall_t __initcall7_start[];
 722 extern initcall_t __initcall_end[];
 723
 724 static initcall_t *initcall_levels[] __initdata = {
 725         __initcall0_start,
 726         __initcall1_start,
 727         __initcall2_start,
 728         __initcall3_start,
 729         __initcall4_start,
 730         __initcall5_start,
 731         __initcall6_start,
 732         __initcall7_start,
 733         __initcall_end,
 734 };
 735
 736 /* Keep these in sync with initcalls in include/linux/init.h */
 737 static char *initcall_level_names[] __initdata = {
 738         "early",
 739         "core",
 740         "postcore",
 741         "arch",
 742         "subsys",
 743         "fs",
 744         "device",
 745         "late",
 746 };
 747
 748 static void __init do_initcall_level(int level)
 749 {
 750         extern const struct kernel_param __start___param[], __stop___param[];
 751         initcall_t *fn;
 752
 753         strcpy(static_command_line, saved_command_line);
 754         parse_args(initcall_level_names[level],
 755                    static_command_line, __start___param,
 756                    __stop___param - __start___param,
 757                    level, level,
 758                    &repair_env_string);
 759
 760         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 761                 do_one_initcall(*fn);
 762 }
 763
 764 static void __init do_initcalls(void)
 765 {
 766         int level;
 767
 768         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
 769                 do_initcall_level(level);
 770 }
 771
 772 /*
 773  * Ok, the machine is now initialized. None of the devices
 774  * have been touched yet, but the CPU subsystem is up and
 775  * running, and memory and process management works.
 776  *
 777  * Now we can finally start doing some real work..
 778  */
 779 static void __init do_basic_setup(void)
 780 {
 781         cpuset_init_smp();
 782         usermodehelper_init();
 783         shmem_init();
 784         driver_init();
 785         init_irq_proc();
 786         do_ctors();
 787         usermodehelper_enable();
 788         do_initcalls();
 789 }
 790
 791 static void __init do_pre_smp_initcalls(void)
 792 {
 793         initcall_t *fn;
 794
 795         for (fn = __initcall_start; fn < __initcall0_start; fn++)
 796                 do_one_initcall(*fn);
 797 }
 798
 799 /*
 800  * This function requests modules which should be loaded by default and is
 801  * called twice right after initrd is mounted and right before init is
 802  * exec'd.  If such modules are on either initrd or rootfs, they will be
 803  * loaded before control is passed to userland.
 804  */
 805 void __init load_default_modules(void)
 806 {
 807         load_default_elevator_module();
 808 }
 809
 810 static int run_init_process(const char *init_filename)
 811 {
 812         argv_init[0] = init_filename;
 813         return do_execve(init_filename,
 814                 (const char __user *const __user *)argv_init,
 815                 (const char __user *const __user *)envp_init);
 816 }
 817
 818 static noinline void __init kernel_init_freeable(void);
 819
 820 static int __ref kernel_init(void *unused)
 821 {
 822         kernel_init_freeable();
 823         /* need to finish all async __init code before freeing the memory */
 824         async_synchronize_full();
 825         free_initmem();
 826         mark_rodata_ro();
 827         system_state = SYSTEM_RUNNING;
 828         numa_default_policy();
 829
 830         flush_delayed_fput();
 831
 832         if (ramdisk_execute_command) {
 833                 if (!run_init_process(ramdisk_execute_command))
 834                         return 0;
 835                 printk(KERN_WARNING "Failed to execute %s\n",
 836                                 ramdisk_execute_command);
 837         }
 838
 839         /*
 840          * We try each of these until one succeeds.
 841          *
 842          * The Bourne shell can be used instead of init if we are
 843          * trying to recover a really broken machine.
 844          */
 845         if (execute_command) {
 846                 if (!run_init_process(execute_command))
 847                         return 0;
 848                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 849                                         "defaults...\n", execute_command);
 850         }
 851         if (!run_init_process("/sbin/init") ||
 852             !run_init_process("/etc/init") ||
 853             !run_init_process("/bin/init") ||
 854             !run_init_process("/bin/sh"))
 855                 return 0;
 856
 857         panic("No init found.  Try passing init= option to kernel. "
 858               "See Linux Documentation/init.txt for guidance.");
 859 }
 860
 861 static noinline void __init kernel_init_freeable(void)
 862 {
 863         /*
 864          * Wait until kthreadd is all set-up.
 865          */
 866         wait_for_completion(&kthreadd_done);
 867
 868         /* Now the scheduler is fully set up and can do blocking allocations */
 869         gfp_allowed_mask = __GFP_BITS_MASK;
 870
 871         /*
 872          * init can allocate pages on any node
 873          */
 874         set_mems_allowed(node_states[N_MEMORY]);
 875         /*
 876          * init can run on any cpu.
 877          */
 878         set_cpus_allowed_ptr(current, cpu_all_mask);
 879
 880         cad_pid = task_pid(current);
 881
 882         smp_prepare_cpus(setup_max_cpus);
 883
 884         do_pre_smp_initcalls();
 885         lockup_detector_init();
 886
 887         smp_init();
 888         sched_init_smp();
 889
 890         do_basic_setup();
 891
 892         /* Open the /dev/console on the rootfs, this should never fail */
 893         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 894                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 895
 896         (void) sys_dup(0);
 897         (void) sys_dup(0);
 898         /*
 899          * check if there is an early userspace init.  If yes, let it do all
 900          * the work
 901          */
 902
 903         if (!ramdisk_execute_command)
 904                 ramdisk_execute_command = "/init";
 905
 906         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 907                 ramdisk_execute_command = NULL;
 908                 prepare_namespace();
 909         }
 910
 911         /*
 912          * Ok, we have completed the initial bootup, and
 913          * we're essentially up and running. Get rid of the
 914          * initmem segments and start the user-mode stuff..
 915          */
 916
 917         /* rootfs is available now, try loading default modules */
 918         load_default_modules();
 919 }