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
  71 #include <asm/io.h>
  72 #include <asm/bugs.h>
  73 #include <asm/setup.h>
  74 #include <asm/sections.h>
  75 #include <asm/cacheflush.h>
  76
  77 #ifdef CONFIG_X86_LOCAL_APIC
  78 #include <asm/smp.h>
  79 #endif
  80
  81 static int kernel_init(void *);
  82
  83 extern void init_IRQ(void);
  84 extern void fork_init(unsigned long);
  85 extern void mca_init(void);
  86 extern void sbus_init(void);
  87 extern void prio_tree_init(void);
  88 extern void radix_tree_init(void);
  89 extern void free_initmem(void);
  90 #ifndef CONFIG_DEBUG_RODATA
  91 static inline void mark_rodata_ro(void) { }
  92 #endif
  93
  94 #ifdef CONFIG_TC
  95 extern void tc_init(void);
  96 #endif
  97
  98 enum system_states system_state __read_mostly;
  99 EXPORT_SYMBOL(system_state);
 100
 101 /*
 102  * Boot command-line arguments
 103  */
 104 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 105 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 106
 107 extern void time_init(void);
 108 /* Default late time init is NULL. archs can override this later. */
 109 void (*__initdata late_time_init)(void);
 110 extern void softirq_init(void);
 111
 112 /* Untouched command line saved by arch-specific code. */
 113 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 114 /* Untouched saved command line (eg. for /proc) */
 115 char *saved_command_line;
 116 /* Command line for parameter parsing */
 117 static char *static_command_line;
 118
 119 static char *execute_command;
 120 static char *ramdisk_execute_command;
 121
 122 #ifdef CONFIG_SMP
 123 /* Setup configured maximum number of CPUs to activate */
 124 unsigned int setup_max_cpus = NR_CPUS;
 125 EXPORT_SYMBOL(setup_max_cpus);
 126
 127
 128 /*
 129  * Setup routine for controlling SMP activation
 130  *
 131  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 132  * activation entirely (the MPS table probe still happens, though).
 133  *
 134  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 135  * greater than 0, limits the maximum number of CPUs activated in
 136  * SMP mode to <NUM>.
 137  */
 138
 139 void __weak arch_disable_smp_support(void) { }
 140
 141 static int __init nosmp(char *str)
 142 {
 143         setup_max_cpus = 0;
 144         arch_disable_smp_support();
 145
 146         return 0;
 147 }
 148
 149 early_param("nosmp", nosmp);
 150
 151 /* this is hard limit */
 152 static int __init nrcpus(char *str)
 153 {
 154         int nr_cpus;
 155
 156         get_option(&str, &nr_cpus);
 157         if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
 158                 nr_cpu_ids = nr_cpus;
 159
 160         return 0;
 161 }
 162
 163 early_param("nr_cpus", nrcpus);
 164
 165 static int __init maxcpus(char *str)
 166 {
 167         get_option(&str, &setup_max_cpus);
 168         if (setup_max_cpus == 0)
 169                 arch_disable_smp_support();
 170
 171         return 0;
 172 }
 173
 174 early_param("maxcpus", maxcpus);
 175 #else
 176 static const unsigned int setup_max_cpus = NR_CPUS;
 177 #endif
 178
 179 /*
 180  * If set, this is an indication to the drivers that reset the underlying
 181  * device before going ahead with the initialization otherwise driver might
 182  * rely on the BIOS and skip the reset operation.
 183  *
 184  * This is useful if kernel is booting in an unreliable environment.
 185  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 186  * skipped and devices will be in unknown state.
 187  */
 188 unsigned int reset_devices;
 189 EXPORT_SYMBOL(reset_devices);
 190
 191 static int __init set_reset_devices(char *str)
 192 {
 193         reset_devices = 1;
 194         return 1;
 195 }
 196
 197 __setup("reset_devices", set_reset_devices);
 198
 199 static const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 200 const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 201 static const char *panic_later, *panic_param;
 202
 203 extern const struct obs_kernel_param __setup_start[], __setup_end[];
 204
 205 static int __init obsolete_checksetup(char *line)
 206 {
 207         const struct obs_kernel_param *p;
 208         int had_early_param = 0;
 209
 210         p = __setup_start;
 211         do {
 212                 int n = strlen(p->str);
 213                 if (!strncmp(line, p->str, n)) {
 214                         if (p->early) {
 215                                 /* Already done in parse_early_param?
 216                                  * (Needs exact match on param part).
 217                                  * Keep iterating, as we can have early
 218                                  * params and __setups of same names 8( */
 219                                 if (line[n] == '\0' || line[n] == '=')
 220                                         had_early_param = 1;
 221                         } else if (!p->setup_func) {
 222                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 223                                        " ignored\n", p->str);
 224                                 return 1;
 225                         } else if (p->setup_func(line + n))
 226                                 return 1;
 227                 }
 228                 p++;
 229         } while (p < __setup_end);
 230
 231         return had_early_param;
 232 }
 233
 234 /*
 235  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 236  * still work even if initially too large, it will just take slightly longer
 237  */
 238 unsigned long loops_per_jiffy = (1<<12);
 239
 240 EXPORT_SYMBOL(loops_per_jiffy);
 241
 242 static int __init debug_kernel(char *str)
 243 {
 244         console_loglevel = 10;
 245         return 0;
 246 }
 247
 248 static int __init quiet_kernel(char *str)
 249 {
 250         console_loglevel = 4;
 251         return 0;
 252 }
 253
 254 early_param("debug", debug_kernel);
 255 early_param("quiet", quiet_kernel);
 256
 257 static int __init loglevel(char *str)
 258 {
 259         get_option(&str, &console_loglevel);
 260         return 0;
 261 }
 262
 263 early_param("loglevel", loglevel);
 264
 265 /*
 266  * Unknown boot options get handed to init, unless they look like
 267  * unused parameters (modprobe will find them in /proc/cmdline).
 268  */
 269 static int __init unknown_bootoption(char *param, char *val)
 270 {
 271         /* Change NUL term back to "=", to make "param" the whole string. */
 272         if (val) {
 273                 /* param=val or param="val"? */
 274                 if (val == param+strlen(param)+1)
 275                         val[-1] = '=';
 276                 else if (val == param+strlen(param)+2) {
 277                         val[-2] = '=';
 278                         memmove(val-1, val, strlen(val)+1);
 279                         val--;
 280                 } else
 281                         BUG();
 282         }
 283
 284         /* Handle obsolete-style parameters */
 285         if (obsolete_checksetup(param))
 286                 return 0;
 287
 288         /* Unused module parameter. */
 289         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
 290                 return 0;
 291
 292         if (panic_later)
 293                 return 0;
 294
 295         if (val) {
 296                 /* Environment option */
 297                 unsigned int i;
 298                 for (i = 0; envp_init[i]; i++) {
 299                         if (i == MAX_INIT_ENVS) {
 300                                 panic_later = "Too many boot env vars at `%s'";
 301                                 panic_param = param;
 302                         }
 303                         if (!strncmp(param, envp_init[i], val - param))
 304                                 break;
 305                 }
 306                 envp_init[i] = param;
 307         } else {
 308                 /* Command line option */
 309                 unsigned int i;
 310                 for (i = 0; argv_init[i]; i++) {
 311                         if (i == MAX_INIT_ARGS) {
 312                                 panic_later = "Too many boot init vars at `%s'";
 313                                 panic_param = param;
 314                         }
 315                 }
 316                 argv_init[i] = param;
 317         }
 318         return 0;
 319 }
 320
 321 #ifdef CONFIG_DEBUG_PAGEALLOC
 322 int __read_mostly debug_pagealloc_enabled = 0;
 323 #endif
 324
 325 static int __init init_setup(char *str)
 326 {
 327         unsigned int i;
 328
 329         execute_command = str;
 330         /*
 331          * In case LILO is going to boot us with default command line,
 332          * it prepends "auto" before the whole cmdline which makes
 333          * the shell think it should execute a script with such name.
 334          * So we ignore all arguments entered _before_ init=... [MJ]
 335          */
 336         for (i = 1; i < MAX_INIT_ARGS; i++)
 337                 argv_init[i] = NULL;
 338         return 1;
 339 }
 340 __setup("init=", init_setup);
 341
 342 static int __init rdinit_setup(char *str)
 343 {
 344         unsigned int i;
 345
 346         ramdisk_execute_command = str;
 347         /* See "auto" comment in init_setup */
 348         for (i = 1; i < MAX_INIT_ARGS; i++)
 349                 argv_init[i] = NULL;
 350         return 1;
 351 }
 352 __setup("rdinit=", rdinit_setup);
 353
 354 #ifndef CONFIG_SMP
 355
 356 #ifdef CONFIG_X86_LOCAL_APIC
 357 static void __init smp_init(void)
 358 {
 359         APIC_init_uniprocessor();
 360 }
 361 #else
 362 #define smp_init()      do { } while (0)
 363 #endif
 364
 365 static inline void setup_nr_cpu_ids(void) { }
 366 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 367
 368 #else
 369
 370 /* Setup number of possible processor ids */
 371 int nr_cpu_ids __read_mostly = NR_CPUS;
 372 EXPORT_SYMBOL(nr_cpu_ids);
 373
 374 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 375 static void __init setup_nr_cpu_ids(void)
 376 {
 377         nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 378 }
 379
 380 /* Called by boot processor to activate the rest. */
 381 static void __init smp_init(void)
 382 {
 383         unsigned int cpu;
 384
 385         /* FIXME: This should be done in userspace --RR */
 386         for_each_present_cpu(cpu) {
 387                 if (num_online_cpus() >= setup_max_cpus)
 388                         break;
 389                 if (!cpu_online(cpu))
 390                         cpu_up(cpu);
 391         }
 392
 393         /* Any cleanup work */
 394         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 395         smp_cpus_done(setup_max_cpus);
 396 }
 397
 398 #endif
 399
 400 /*
 401  * We need to store the untouched command line for future reference.
 402  * We also need to store the touched command line since the parameter
 403  * parsing is performed in place, and we should allow a component to
 404  * store reference of name/value for future reference.
 405  */
 406 static void __init setup_command_line(char *command_line)
 407 {
 408         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 409         static_command_line = alloc_bootmem(strlen (command_line)+1);
 410         strcpy (saved_command_line, boot_command_line);
 411         strcpy (static_command_line, command_line);
 412 }
 413
 414 /*
 415  * We need to finalize in a non-__init function or else race conditions
 416  * between the root thread and the init thread may cause start_kernel to
 417  * be reaped by free_initmem before the root thread has proceeded to
 418  * cpu_idle.
 419  *
 420  * gcc-3.4 accidentally inlines this function, so use noinline.
 421  */
 422
 423 static __initdata DECLARE_COMPLETION(kthreadd_done);
 424
 425 static noinline void __init_refok rest_init(void)
 426 {
 427         int pid;
 428
 429         rcu_scheduler_starting();
 430         /*
 431          * We need to spawn init first so that it obtains pid 1, however
 432          * the init task will end up wanting to create kthreads, which, if
 433          * we schedule it before we create kthreadd, will OOPS.
 434          */
 435         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 436         numa_default_policy();
 437         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 438         rcu_read_lock();
 439         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 440         rcu_read_unlock();
 441         complete(&kthreadd_done);
 442
 443         /*
 444          * The boot idle thread must execute schedule()
 445          * at least once to get things moving:
 446          */
 447         init_idle_bootup_task(current);
 448         preempt_enable_no_resched();
 449         schedule();
 450         preempt_disable();
 451
 452         /* Call into cpu_idle with preempt disabled */
 453         cpu_idle();
 454 }
 455
 456 /* Check for early params. */
 457 static int __init do_early_param(char *param, char *val)
 458 {
 459         const struct obs_kernel_param *p;
 460
 461         for (p = __setup_start; p < __setup_end; p++) {
 462                 if ((p->early && strcmp(param, p->str) == 0) ||
 463                     (strcmp(param, "console") == 0 &&
 464                      strcmp(p->str, "earlycon") == 0)
 465                 ) {
 466                         if (p->setup_func(val) != 0)
 467                                 printk(KERN_WARNING
 468                                        "Malformed early option '%s'\n", param);
 469                 }
 470         }
 471         /* We accept everything at this stage. */
 472         return 0;
 473 }
 474
 475 void __init parse_early_options(char *cmdline)
 476 {
 477         parse_args("early options", cmdline, NULL, 0, do_early_param);
 478 }
 479
 480 /* Arch code calls this early on, or if not, just before other parsing. */
 481 void __init parse_early_param(void)
 482 {
 483         static __initdata int done = 0;
 484         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 485
 486         if (done)
 487                 return;
 488
 489         /* All fall through to do_early_param. */
 490         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 491         parse_early_options(tmp_cmdline);
 492         done = 1;
 493 }
 494
 495 /*
 496  *      Activate the first processor.
 497  */
 498
 499 static void __init boot_cpu_init(void)
 500 {
 501         int cpu = smp_processor_id();
 502         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 503         set_cpu_online(cpu, true);
 504         set_cpu_active(cpu, true);
 505         set_cpu_present(cpu, true);
 506         set_cpu_possible(cpu, true);
 507 }
 508
 509 void __init __weak smp_setup_processor_id(void)
 510 {
 511 }
 512
 513 void __init __weak thread_info_cache_init(void)
 514 {
 515 }
 516
 517 /*
 518  * Set up kernel memory allocators
 519  */
 520 static void __init mm_init(void)
 521 {
 522         /*
 523          * page_cgroup requires countinous pages as memmap
 524          * and it's bigger than MAX_ORDER unless SPARSEMEM.
 525          */
 526         page_cgroup_init_flatmem();
 527         mem_init();
 528         kmem_cache_init();
 529         percpu_init_late();
 530         pgtable_cache_init();
 531         vmalloc_init();
 532 }
 533
 534 asmlinkage void __init start_kernel(void)
 535 {
 536         char * command_line;
 537         extern const struct kernel_param __start___param[], __stop___param[];
 538
 539         smp_setup_processor_id();
 540
 541         /*
 542          * Need to run as early as possible, to initialize the
 543          * lockdep hash:
 544          */
 545         lockdep_init();
 546         debug_objects_early_init();
 547
 548         /*
 549          * Set up the the initial canary ASAP:
 550          */
 551         boot_init_stack_canary();
 552
 553         cgroup_init_early();
 554
 555         local_irq_disable();
 556         early_boot_irqs_off();
 557
 558 /*
 559  * Interrupts are still disabled. Do necessary setups, then
 560  * enable them
 561  */
 562         tick_init();
 563         boot_cpu_init();
 564         page_address_init();
 565         printk(KERN_NOTICE "%s", linux_banner);
 566         setup_arch(&command_line);
 567         mm_init_owner(&init_mm, &init_task);
 568         setup_command_line(command_line);
 569         setup_nr_cpu_ids();
 570         setup_per_cpu_areas();
 571         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 572
 573         build_all_zonelists(NULL);
 574         page_alloc_init();
 575
 576         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 577         parse_early_param();
 578         parse_args("Booting kernel", static_command_line, __start___param,
 579                    __stop___param - __start___param,
 580                    &unknown_bootoption);
 581         /*
 582          * These use large bootmem allocations and must precede
 583          * kmem_cache_init()
 584          */
 585         pidhash_init();
 586         vfs_caches_init_early();
 587         sort_main_extable();
 588         trap_init();
 589         mm_init();
 590         /*
 591          * Set up the scheduler prior starting any interrupts (such as the
 592          * timer interrupt). Full topology setup happens at smp_init()
 593          * time - but meanwhile we still have a functioning scheduler.
 594          */
 595         sched_init();
 596         /*
 597          * Disable preemption - early bootup scheduling is extremely
 598          * fragile until we cpu_idle() for the first time.
 599          */
 600         preempt_disable();
 601         if (!irqs_disabled()) {
 602                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 603                                 "enabled *very* early, fixing it\n");
 604                 local_irq_disable();
 605         }
 606         rcu_init();
 607         radix_tree_init();
 608         /* init some links before init_ISA_irqs() */
 609         early_irq_init();
 610         init_IRQ();
 611         prio_tree_init();
 612         init_timers();
 613         hrtimers_init();
 614         softirq_init();
 615         timekeeping_init();
 616         time_init();
 617         profile_init();
 618         if (!irqs_disabled())
 619                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 620                                  "enabled early\n");
 621         early_boot_irqs_on();
 622         local_irq_enable();
 623
 624         /* Interrupts are enabled now so all GFP allocations are safe. */
 625         gfp_allowed_mask = __GFP_BITS_MASK;
 626
 627         kmem_cache_init_late();
 628
 629         /*
 630          * HACK ALERT! This is early. We're enabling the console before
 631          * we've done PCI setups etc, and console_init() must be aware of
 632          * this. But we do want output early, in case something goes wrong.
 633          */
 634         console_init();
 635         if (panic_later)
 636                 panic(panic_later, panic_param);
 637
 638         lockdep_info();
 639
 640         /*
 641          * Need to run this when irqs are enabled, because it wants
 642          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 643          * too:
 644          */
 645         locking_selftest();
 646
 647 #ifdef CONFIG_BLK_DEV_INITRD
 648         if (initrd_start && !initrd_below_start_ok &&
 649             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 650                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 651                     "disabling it.\n",
 652                     page_to_pfn(virt_to_page((void *)initrd_start)),
 653                     min_low_pfn);
 654                 initrd_start = 0;
 655         }
 656 #endif
 657         page_cgroup_init();
 658         enable_debug_pagealloc();
 659         kmemleak_init();
 660         debug_objects_mem_init();
 661         idr_init_cache();
 662         setup_per_cpu_pageset();
 663         numa_policy_init();
 664         if (late_time_init)
 665                 late_time_init();
 666         sched_clock_init();
 667         calibrate_delay();
 668         pidmap_init();
 669         anon_vma_init();
 670 #ifdef CONFIG_X86
 671         if (efi_enabled)
 672                 efi_enter_virtual_mode();
 673 #endif
 674         thread_info_cache_init();
 675         cred_init();
 676         fork_init(totalram_pages);
 677         proc_caches_init();
 678         buffer_init();
 679         key_init();
 680         security_init();
 681         dbg_late_init();
 682         vfs_caches_init(totalram_pages);
 683         signals_init();
 684         /* rootfs populating might need page-writeback */
 685         page_writeback_init();
 686 #ifdef CONFIG_PROC_FS
 687         proc_root_init();
 688 #endif
 689         cgroup_init();
 690         cpuset_init();
 691         taskstats_init_early();
 692         delayacct_init();
 693
 694         check_bugs();
 695
 696         acpi_early_init(); /* before LAPIC and SMP init */
 697         sfi_init_late();
 698
 699         ftrace_init();
 700
 701         /* Do the rest non-__init'ed, we're now alive */
 702         rest_init();
 703 }
 704
 705 /* Call all constructor functions linked into the kernel. */
 706 static void __init do_ctors(void)
 707 {
 708 #ifdef CONFIG_CONSTRUCTORS
 709         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
 710
 711         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
 712                 (*fn)();
 713 #endif
 714 }
 715
 716 int initcall_debug;
 717 core_param(initcall_debug, initcall_debug, bool, 0644);
 718
 719 static char msgbuf[64];
 720
 721 static int __init_or_module do_one_initcall_debug(initcall_t fn)
 722 {
 723         ktime_t calltime, delta, rettime;
 724         unsigned long long duration;
 725         int ret;
 726
 727         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 728         calltime = ktime_get();
 729         ret = fn();
 730         rettime = ktime_get();
 731         delta = ktime_sub(rettime, calltime);
 732         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 733         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn,
 734                 ret, duration);
 735
 736         return ret;
 737 }
 738
 739 int __init_or_module do_one_initcall(initcall_t fn)
 740 {
 741         int count = preempt_count();
 742         int ret;
 743
 744         if (initcall_debug)
 745                 ret = do_one_initcall_debug(fn);
 746         else
 747                 ret = fn();
 748
 749         msgbuf[0] = 0;
 750
 751         if (ret && ret != -ENODEV && initcall_debug)
 752                 sprintf(msgbuf, "error code %d ", ret);
 753
 754         if (preempt_count() != count) {
 755                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 756                 preempt_count() = count;
 757         }
 758         if (irqs_disabled()) {
 759                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 760                 local_irq_enable();
 761         }
 762         if (msgbuf[0]) {
 763                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 764         }
 765
 766         return ret;
 767 }
 768
 769
 770 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
 771
 772 static void __init do_initcalls(void)
 773 {
 774         initcall_t *fn;
 775
 776         for (fn = __early_initcall_end; fn < __initcall_end; fn++)
 777                 do_one_initcall(*fn);
 778
 779         /* Make sure there is no pending stuff from the initcall sequence */
 780         flush_scheduled_work();
 781 }
 782
 783 /*
 784  * Ok, the machine is now initialized. None of the devices
 785  * have been touched yet, but the CPU subsystem is up and
 786  * running, and memory and process management works.
 787  *
 788  * Now we can finally start doing some real work..
 789  */
 790 static void __init do_basic_setup(void)
 791 {
 792         cpuset_init_smp();
 793         usermodehelper_init();
 794         init_tmpfs();
 795         driver_init();
 796         init_irq_proc();
 797         do_ctors();
 798         do_initcalls();
 799 }
 800
 801 static void __init do_pre_smp_initcalls(void)
 802 {
 803         initcall_t *fn;
 804
 805         for (fn = __initcall_start; fn < __early_initcall_end; fn++)
 806                 do_one_initcall(*fn);
 807 }
 808
 809 static void run_init_process(const char *init_filename)
 810 {
 811         argv_init[0] = init_filename;
 812         kernel_execve(init_filename, argv_init, envp_init);
 813 }
 814
 815 /* This is a non __init function. Force it to be noinline otherwise gcc
 816  * makes it inline to init() and it becomes part of init.text section
 817  */
 818 static noinline int init_post(void)
 819 {
 820         /* need to finish all async __init code before freeing the memory */
 821         async_synchronize_full();
 822         free_initmem();
 823         mark_rodata_ro();
 824         system_state = SYSTEM_RUNNING;
 825         numa_default_policy();
 826
 827
 828         current->signal->flags |= SIGNAL_UNKILLABLE;
 829
 830         if (ramdisk_execute_command) {
 831                 run_init_process(ramdisk_execute_command);
 832                 printk(KERN_WARNING "Failed to execute %s\n",
 833                                 ramdisk_execute_command);
 834         }
 835
 836         /*
 837          * We try each of these until one succeeds.
 838          *
 839          * The Bourne shell can be used instead of init if we are
 840          * trying to recover a really broken machine.
 841          */
 842         if (execute_command) {
 843                 run_init_process(execute_command);
 844                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 845                                         "defaults...\n", execute_command);
 846         }
 847         run_init_process("/sbin/init");
 848         run_init_process("/etc/init");
 849         run_init_process("/bin/init");
 850         run_init_process("/bin/sh");
 851
 852         panic("No init found.  Try passing init= option to kernel. "
 853               "See Linux Documentation/init.txt for guidance.");
 854 }
 855
 856 static int __init kernel_init(void * unused)
 857 {
 858         /*
 859          * Wait until kthreadd is all set-up.
 860          */
 861         wait_for_completion(&kthreadd_done);
 862         /*
 863          * init can allocate pages on any node
 864          */
 865         set_mems_allowed(node_states[N_HIGH_MEMORY]);
 866         /*
 867          * init can run on any cpu.
 868          */
 869         set_cpus_allowed_ptr(current, cpu_all_mask);
 870         /*
 871          * Tell the world that we're going to be the grim
 872          * reaper of innocent orphaned children.
 873          *
 874          * We don't want people to have to make incorrect
 875          * assumptions about where in the task array this
 876          * can be found.
 877          */
 878         init_pid_ns.child_reaper = current;
 879
 880         cad_pid = task_pid(current);
 881
 882         smp_prepare_cpus(setup_max_cpus);
 883
 884         do_pre_smp_initcalls();
 885
 886         smp_init();
 887         sched_init_smp();
 888
 889         do_basic_setup();
 890
 891         /* Open the /dev/console on the rootfs, this should never fail */
 892         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 893                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 894
 895         (void) sys_dup(0);
 896         (void) sys_dup(0);
 897         /*
 898          * check if there is an early userspace init.  If yes, let it do all
 899          * the work
 900          */
 901
 902         if (!ramdisk_execute_command)
 903                 ramdisk_execute_command = "/init";
 904
 905         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 906                 ramdisk_execute_command = NULL;
 907                 prepare_namespace();
 908         }
 909
 910         /*
 911          * Ok, we have completed the initial bootup, and
 912          * we're essentially up and running. Get rid of the
 913          * initmem segments and start the user-mode stuff..
 914          */
 915
 916         init_post();
 917         return 0;
 918 }