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