init/main.c

   1 /*
   2  *  linux/init/main.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  GK 2/5/95  -  Changed to support mounting root fs via NFS
   7  *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
   8  *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
   9  *  Simplified starting of init:  Michael A. Griffith <grif@acm.org>
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/module.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/kernel.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/string.h>
  18 #include <linux/ctype.h>
  19 #include <linux/delay.h>
  20 #include <linux/utsname.h>
  21 #include <linux/ioport.h>
  22 #include <linux/init.h>
  23 #include <linux/smp_lock.h>
  24 #include <linux/initrd.h>
  25 #include <linux/hdreg.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/tty.h>
  28 #include <linux/gfp.h>
  29 #include <linux/percpu.h>
  30 #include <linux/kmod.h>
  31 #include <linux/kernel_stat.h>
  32 #include <linux/start_kernel.h>
  33 #include <linux/security.h>
  34 #include <linux/smp.h>
  35 #include <linux/workqueue.h>
  36 #include <linux/profile.h>
  37 #include <linux/rcupdate.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/kallsyms.h>
  40 #include <linux/writeback.h>
  41 #include <linux/cpu.h>
  42 #include <linux/cpuset.h>
  43 #include <linux/cgroup.h>
  44 #include <linux/efi.h>
  45 #include <linux/tick.h>
  46 #include <linux/interrupt.h>
  47 #include <linux/taskstats_kern.h>
  48 #include <linux/delayacct.h>
  49 #include <linux/unistd.h>
  50 #include <linux/rmap.h>
  51 #include <linux/mempolicy.h>
  52 #include <linux/key.h>
  53 #include <linux/unwind.h>
  54 #include <linux/buffer_head.h>
  55 #include <linux/debug_locks.h>
  56 #include <linux/debugobjects.h>
  57 #include <linux/lockdep.h>
  58 #include <linux/pid_namespace.h>
  59 #include <linux/device.h>
  60 #include <linux/kthread.h>
  61 #include <linux/sched.h>
  62 #include <linux/signal.h>
  63 #include <linux/idr.h>
  64
  65 #include <asm/io.h>
  66 #include <asm/bugs.h>
  67 #include <asm/setup.h>
  68 #include <asm/sections.h>
  69 #include <asm/cacheflush.h>
  70
  71 #ifdef CONFIG_X86_LOCAL_APIC
  72 #include <asm/smp.h>
  73 #endif
  74
  75 /*
  76  * This is one of the first .c files built. Error out early if we have compiler
  77  * trouble.
  78  */
  79
  80 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
  81 #warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.
  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 pidhash_init(void);
  91 extern void pidmap_init(void);
  92 extern void prio_tree_init(void);
  93 extern void radix_tree_init(void);
  94 extern void free_initmem(void);
  95 #ifdef  CONFIG_ACPI
  96 extern void acpi_early_init(void);
  97 #else
  98 static inline void acpi_early_init(void) { }
  99 #endif
 100 #ifndef CONFIG_DEBUG_RODATA
 101 static inline void mark_rodata_ro(void) { }
 102 #endif
 103
 104 #ifdef CONFIG_TC
 105 extern void tc_init(void);
 106 #endif
 107
 108 enum system_states system_state;
 109 EXPORT_SYMBOL(system_state);
 110
 111 /*
 112  * Boot command-line arguments
 113  */
 114 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 115 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 116
 117 extern void time_init(void);
 118 /* Default late time init is NULL. archs can override this later. */
 119 void (*late_time_init)(void);
 120 extern void softirq_init(void);
 121
 122 /* Untouched command line saved by arch-specific code. */
 123 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 124 /* Untouched saved command line (eg. for /proc) */
 125 char *saved_command_line;
 126 /* Command line for parameter parsing */
 127 static char *static_command_line;
 128
 129 static char *execute_command;
 130 static char *ramdisk_execute_command;
 131
 132 #ifdef CONFIG_SMP
 133 /* Setup configured maximum number of CPUs to activate */
 134 unsigned int __initdata setup_max_cpus = NR_CPUS;
 135
 136 /*
 137  * Setup routine for controlling SMP activation
 138  *
 139  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 140  * activation entirely (the MPS table probe still happens, though).
 141  *
 142  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 143  * greater than 0, limits the maximum number of CPUs activated in
 144  * SMP mode to <NUM>.
 145  */
 146 #ifndef CONFIG_X86_IO_APIC
 147 static inline void disable_ioapic_setup(void) {};
 148 #endif
 149
 150 static int __init nosmp(char *str)
 151 {
 152         setup_max_cpus = 0;
 153         disable_ioapic_setup();
 154         return 0;
 155 }
 156
 157 early_param("nosmp", nosmp);
 158
 159 static int __init maxcpus(char *str)
 160 {
 161         get_option(&str, &setup_max_cpus);
 162         if (setup_max_cpus == 0)
 163                 disable_ioapic_setup();
 164
 165         return 0;
 166 }
 167
 168 early_param("maxcpus", maxcpus);
 169 #else
 170 #define setup_max_cpus NR_CPUS
 171 #endif
 172
 173 /*
 174  * If set, this is an indication to the drivers that reset the underlying
 175  * device before going ahead with the initialization otherwise driver might
 176  * rely on the BIOS and skip the reset operation.
 177  *
 178  * This is useful if kernel is booting in an unreliable environment.
 179  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 180  * skipped and devices will be in unknown state.
 181  */
 182 unsigned int reset_devices;
 183 EXPORT_SYMBOL(reset_devices);
 184
 185 static int __init set_reset_devices(char *str)
 186 {
 187         reset_devices = 1;
 188         return 1;
 189 }
 190
 191 __setup("reset_devices", set_reset_devices);
 192
 193 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 194 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 195 static const char *panic_later, *panic_param;
 196
 197 extern struct obs_kernel_param __setup_start[], __setup_end[];
 198
 199 static int __init obsolete_checksetup(char *line)
 200 {
 201         struct obs_kernel_param *p;
 202         int had_early_param = 0;
 203
 204         p = __setup_start;
 205         do {
 206                 int n = strlen(p->str);
 207                 if (!strncmp(line, p->str, n)) {
 208                         if (p->early) {
 209                                 /* Already done in parse_early_param?
 210                                  * (Needs exact match on param part).
 211                                  * Keep iterating, as we can have early
 212                                  * params and __setups of same names 8( */
 213                                 if (line[n] == '\0' || line[n] == '=')
 214                                         had_early_param = 1;
 215                         } else if (!p->setup_func) {
 216                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 217                                        " ignored\n", p->str);
 218                                 return 1;
 219                         } else if (p->setup_func(line + n))
 220                                 return 1;
 221                 }
 222                 p++;
 223         } while (p < __setup_end);
 224
 225         return had_early_param;
 226 }
 227
 228 /*
 229  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 230  * still work even if initially too large, it will just take slightly longer
 231  */
 232 unsigned long loops_per_jiffy = (1<<12);
 233
 234 EXPORT_SYMBOL(loops_per_jiffy);
 235
 236 static int __init debug_kernel(char *str)
 237 {
 238         console_loglevel = 10;
 239         return 0;
 240 }
 241
 242 static int __init quiet_kernel(char *str)
 243 {
 244         console_loglevel = 4;
 245         return 0;
 246 }
 247
 248 early_param("debug", debug_kernel);
 249 early_param("quiet", quiet_kernel);
 250
 251 static int __init loglevel(char *str)
 252 {
 253         get_option(&str, &console_loglevel);
 254         return 0;
 255 }
 256
 257 early_param("loglevel", loglevel);
 258
 259 /*
 260  * Unknown boot options get handed to init, unless they look like
 261  * failed parameters
 262  */
 263 static int __init unknown_bootoption(char *param, char *val)
 264 {
 265         /* Change NUL term back to "=", to make "param" the whole string. */
 266         if (val) {
 267                 /* param=val or param="val"? */
 268                 if (val == param+strlen(param)+1)
 269                         val[-1] = '=';
 270                 else if (val == param+strlen(param)+2) {
 271                         val[-2] = '=';
 272                         memmove(val-1, val, strlen(val)+1);
 273                         val--;
 274                 } else
 275                         BUG();
 276         }
 277
 278         /* Handle obsolete-style parameters */
 279         if (obsolete_checksetup(param))
 280                 return 0;
 281
 282         /*
 283          * Preemptive maintenance for "why didn't my misspelled command
 284          * line work?"
 285          */
 286         if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 287                 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 288                 return 0;
 289         }
 290
 291         if (panic_later)
 292                 return 0;
 293
 294         if (val) {
 295                 /* Environment option */
 296                 unsigned int i;
 297                 for (i = 0; envp_init[i]; i++) {
 298                         if (i == MAX_INIT_ENVS) {
 299                                 panic_later = "Too many boot env vars at `%s'";
 300                                 panic_param = param;
 301                         }
 302                         if (!strncmp(param, envp_init[i], val - param))
 303                                 break;
 304                 }
 305                 envp_init[i] = param;
 306         } else {
 307                 /* Command line option */
 308                 unsigned int i;
 309                 for (i = 0; argv_init[i]; i++) {
 310                         if (i == MAX_INIT_ARGS) {
 311                                 panic_later = "Too many boot init vars at `%s'";
 312                                 panic_param = param;
 313                         }
 314                 }
 315                 argv_init[i] = param;
 316         }
 317         return 0;
 318 }
 319
 320 #ifdef CONFIG_DEBUG_PAGEALLOC
 321 int __read_mostly debug_pagealloc_enabled = 0;
 322 #endif
 323
 324 static int __init init_setup(char *str)
 325 {
 326         unsigned int i;
 327
 328         execute_command = str;
 329         /*
 330          * In case LILO is going to boot us with default command line,
 331          * it prepends "auto" before the whole cmdline which makes
 332          * the shell think it should execute a script with such name.
 333          * So we ignore all arguments entered _before_ init=... [MJ]
 334          */
 335         for (i = 1; i < MAX_INIT_ARGS; i++)
 336                 argv_init[i] = NULL;
 337         return 1;
 338 }
 339 __setup("init=", init_setup);
 340
 341 static int __init rdinit_setup(char *str)
 342 {
 343         unsigned int i;
 344
 345         ramdisk_execute_command = str;
 346         /* See "auto" comment in init_setup */
 347         for (i = 1; i < MAX_INIT_ARGS; i++)
 348                 argv_init[i] = NULL;
 349         return 1;
 350 }
 351 __setup("rdinit=", rdinit_setup);
 352
 353 #ifndef CONFIG_SMP
 354
 355 #ifdef CONFIG_X86_LOCAL_APIC
 356 static void __init smp_init(void)
 357 {
 358         APIC_init_uniprocessor();
 359 }
 360 #else
 361 #define smp_init()      do { } while (0)
 362 #endif
 363
 364 static inline void setup_per_cpu_areas(void) { }
 365 static inline void setup_nr_cpu_ids(void) { }
 366 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 367
 368 #else
 369
 370 #if NR_CPUS > BITS_PER_LONG
 371 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
 372 EXPORT_SYMBOL(cpu_mask_all);
 373 #endif
 374
 375 /* Setup number of possible processor ids */
 376 int nr_cpu_ids __read_mostly = NR_CPUS;
 377 EXPORT_SYMBOL(nr_cpu_ids);
 378
 379 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 380 static void __init setup_nr_cpu_ids(void)
 381 {
 382         int cpu, highest_cpu = 0;
 383
 384         for_each_possible_cpu(cpu)
 385                 highest_cpu = cpu;
 386
 387         nr_cpu_ids = highest_cpu + 1;
 388 }
 389
 390 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
 391 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 392
 393 EXPORT_SYMBOL(__per_cpu_offset);
 394
 395 static void __init setup_per_cpu_areas(void)
 396 {
 397         unsigned long size, i;
 398         char *ptr;
 399         unsigned long nr_possible_cpus = num_possible_cpus();
 400
 401         /* Copy section for each CPU (we discard the original) */
 402         size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
 403         ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 404
 405         for_each_possible_cpu(i) {
 406                 __per_cpu_offset[i] = ptr - __per_cpu_start;
 407                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 408                 ptr += size;
 409         }
 410 }
 411 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
 412
 413 /* Called by boot processor to activate the rest. */
 414 static void __init smp_init(void)
 415 {
 416         unsigned int cpu;
 417
 418         /* FIXME: This should be done in userspace --RR */
 419         for_each_present_cpu(cpu) {
 420                 if (num_online_cpus() >= setup_max_cpus)
 421                         break;
 422                 if (!cpu_online(cpu))
 423                         cpu_up(cpu);
 424         }
 425
 426         /* Any cleanup work */
 427         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 428         smp_cpus_done(setup_max_cpus);
 429 }
 430
 431 #endif
 432
 433 /*
 434  * We need to store the untouched command line for future reference.
 435  * We also need to store the touched command line since the parameter
 436  * parsing is performed in place, and we should allow a component to
 437  * store reference of name/value for future reference.
 438  */
 439 static void __init setup_command_line(char *command_line)
 440 {
 441         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 442         static_command_line = alloc_bootmem(strlen (command_line)+1);
 443         strcpy (saved_command_line, boot_command_line);
 444         strcpy (static_command_line, command_line);
 445 }
 446
 447 /*
 448  * We need to finalize in a non-__init function or else race conditions
 449  * between the root thread and the init thread may cause start_kernel to
 450  * be reaped by free_initmem before the root thread has proceeded to
 451  * cpu_idle.
 452  *
 453  * gcc-3.4 accidentally inlines this function, so use noinline.
 454  */
 455
 456 static void noinline __init_refok rest_init(void)
 457         __releases(kernel_lock)
 458 {
 459         int pid;
 460
 461         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 462         numa_default_policy();
 463         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 464         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 465         unlock_kernel();
 466
 467         /*
 468          * The boot idle thread must execute schedule()
 469          * at least once to get things moving:
 470          */
 471         init_idle_bootup_task(current);
 472         preempt_enable_no_resched();
 473         schedule();
 474         preempt_disable();
 475
 476         /* Call into cpu_idle with preempt disabled */
 477         cpu_idle();
 478 }
 479
 480 /* Check for early params. */
 481 static int __init do_early_param(char *param, char *val)
 482 {
 483         struct obs_kernel_param *p;
 484
 485         for (p = __setup_start; p < __setup_end; p++) {
 486                 if ((p->early && strcmp(param, p->str) == 0) ||
 487                     (strcmp(param, "console") == 0 &&
 488                      strcmp(p->str, "earlycon") == 0)
 489                 ) {
 490                         if (p->setup_func(val) != 0)
 491                                 printk(KERN_WARNING
 492                                        "Malformed early option '%s'\n", param);
 493                 }
 494         }
 495         /* We accept everything at this stage. */
 496         return 0;
 497 }
 498
 499 /* Arch code calls this early on, or if not, just before other parsing. */
 500 void __init parse_early_param(void)
 501 {
 502         static __initdata int done = 0;
 503         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 504
 505         if (done)
 506                 return;
 507
 508         /* All fall through to do_early_param. */
 509         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 510         parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 511         done = 1;
 512 }
 513
 514 /*
 515  *      Activate the first processor.
 516  */
 517
 518 static void __init boot_cpu_init(void)
 519 {
 520         int cpu = smp_processor_id();
 521         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 522         cpu_set(cpu, cpu_online_map);
 523         cpu_set(cpu, cpu_present_map);
 524         cpu_set(cpu, cpu_possible_map);
 525 }
 526
 527 void __init __weak smp_setup_processor_id(void)
 528 {
 529 }
 530
 531 void __init __weak thread_info_cache_init(void)
 532 {
 533 }
 534
 535 asmlinkage void __init start_kernel(void)
 536 {
 537         char * command_line;
 538         extern struct kernel_param __start___param[], __stop___param[];
 539
 540         smp_setup_processor_id();
 541
 542         /*
 543          * Need to run as early as possible, to initialize the
 544          * lockdep hash:
 545          */
 546         unwind_init();
 547         lockdep_init();
 548         debug_objects_early_init();
 549         cgroup_init_early();
 550
 551         local_irq_disable();
 552         early_boot_irqs_off();
 553         early_init_irq_lock_class();
 554
 555 /*
 556  * Interrupts are still disabled. Do necessary setups, then
 557  * enable them
 558  */
 559         lock_kernel();
 560         tick_init();
 561         boot_cpu_init();
 562         page_address_init();
 563         printk(KERN_NOTICE);
 564         printk(linux_banner);
 565         setup_arch(&command_line);
 566         mm_init_owner(&init_mm, &init_task);
 567         setup_command_line(command_line);
 568         unwind_setup();
 569         setup_per_cpu_areas();
 570         setup_nr_cpu_ids();
 571         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 572
 573         /*
 574          * Set up the scheduler prior starting any interrupts (such as the
 575          * timer interrupt). Full topology setup happens at smp_init()
 576          * time - but meanwhile we still have a functioning scheduler.
 577          */
 578         sched_init();
 579         /*
 580          * Disable preemption - early bootup scheduling is extremely
 581          * fragile until we cpu_idle() for the first time.
 582          */
 583         preempt_disable();
 584         build_all_zonelists();
 585         page_alloc_init();
 586         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 587         parse_early_param();
 588         parse_args("Booting kernel", static_command_line, __start___param,
 589                    __stop___param - __start___param,
 590                    &unknown_bootoption);
 591         if (!irqs_disabled()) {
 592                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 593                                 "enabled *very* early, fixing it\n");
 594                 local_irq_disable();
 595         }
 596         sort_main_extable();
 597         trap_init();
 598         rcu_init();
 599         init_IRQ();
 600         pidhash_init();
 601         init_timers();
 602         hrtimers_init();
 603         softirq_init();
 604         timekeeping_init();
 605         time_init();
 606         sched_clock_init();
 607         profile_init();
 608         if (!irqs_disabled())
 609                 printk("start_kernel(): bug: interrupts were enabled early\n");
 610         early_boot_irqs_on();
 611         local_irq_enable();
 612
 613         /*
 614          * HACK ALERT! This is early. We're enabling the console before
 615          * we've done PCI setups etc, and console_init() must be aware of
 616          * this. But we do want output early, in case something goes wrong.
 617          */
 618         console_init();
 619         if (panic_later)
 620                 panic(panic_later, panic_param);
 621
 622         lockdep_info();
 623
 624         /*
 625          * Need to run this when irqs are enabled, because it wants
 626          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 627          * too:
 628          */
 629         locking_selftest();
 630
 631 #ifdef CONFIG_BLK_DEV_INITRD
 632         if (initrd_start && !initrd_below_start_ok &&
 633                         initrd_start < min_low_pfn << PAGE_SHIFT) {
 634                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 635                     "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 636                 initrd_start = 0;
 637         }
 638 #endif
 639         vfs_caches_init_early();
 640         cpuset_init_early();
 641         mem_init();
 642         enable_debug_pagealloc();
 643         cpu_hotplug_init();
 644         kmem_cache_init();
 645         debug_objects_mem_init();
 646         idr_init_cache();
 647         setup_per_cpu_pageset();
 648         numa_policy_init();
 649         if (late_time_init)
 650                 late_time_init();
 651         calibrate_delay();
 652         pidmap_init();
 653         pgtable_cache_init();
 654         prio_tree_init();
 655         anon_vma_init();
 656 #ifdef CONFIG_X86
 657         if (efi_enabled)
 658                 efi_enter_virtual_mode();
 659 #endif
 660         thread_info_cache_init();
 661         fork_init(num_physpages);
 662         proc_caches_init();
 663         buffer_init();
 664         unnamed_dev_init();
 665         key_init();
 666         security_init();
 667         vfs_caches_init(num_physpages);
 668         radix_tree_init();
 669         signals_init();
 670         /* rootfs populating might need page-writeback */
 671         page_writeback_init();
 672 #ifdef CONFIG_PROC_FS
 673         proc_root_init();
 674 #endif
 675         cgroup_init();
 676         cpuset_init();
 677         taskstats_init_early();
 678         delayacct_init();
 679
 680         check_bugs();
 681
 682         acpi_early_init(); /* before LAPIC and SMP init */
 683
 684         /* Do the rest non-__init'ed, we're now alive */
 685         rest_init();
 686 }
 687
 688 static int __initdata initcall_debug;
 689
 690 static int __init initcall_debug_setup(char *str)
 691 {
 692         initcall_debug = 1;
 693         return 1;
 694 }
 695 __setup("initcall_debug", initcall_debug_setup);
 696
 697 static void __init do_one_initcall(initcall_t fn)
 698 {
 699         int count = preempt_count();
 700         ktime_t t0, t1, delta;
 701         char msgbuf[64];
 702         int result;
 703
 704         if (initcall_debug) {
 705                 print_fn_descriptor_symbol("calling  %s\n", fn);
 706                 t0 = ktime_get();
 707         }
 708
 709         result = fn();
 710
 711         if (initcall_debug) {
 712                 t1 = ktime_get();
 713                 delta = ktime_sub(t1, t0);
 714
 715                 print_fn_descriptor_symbol("initcall %s", fn);
 716                 printk(" returned %d after %Ld msecs\n", result,
 717                         (unsigned long long) delta.tv64 >> 20);
 718         }
 719
 720         msgbuf[0] = 0;
 721
 722         if (result && result != -ENODEV && initcall_debug)
 723                 sprintf(msgbuf, "error code %d ", result);
 724
 725         if (preempt_count() != count) {
 726                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 727                 preempt_count() = count;
 728         }
 729         if (irqs_disabled()) {
 730                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 731                 local_irq_enable();
 732         }
 733         if (msgbuf[0]) {
 734                 print_fn_descriptor_symbol(KERN_WARNING "initcall %s", fn);
 735                 printk(" returned with %s\n", msgbuf);
 736         }
 737 }
 738
 739
 740 extern initcall_t __initcall_start[], __initcall_end[];
 741
 742 static void __init do_initcalls(void)
 743 {
 744         initcall_t *call;
 745
 746         for (call = __initcall_start; call < __initcall_end; call++)
 747                 do_one_initcall(*call);
 748
 749         /* Make sure there is no pending stuff from the initcall sequence */
 750         flush_scheduled_work();
 751 }
 752
 753 /*
 754  * Ok, the machine is now initialized. None of the devices
 755  * have been touched yet, but the CPU subsystem is up and
 756  * running, and memory and process management works.
 757  *
 758  * Now we can finally start doing some real work..
 759  */
 760 static void __init do_basic_setup(void)
 761 {
 762         rcu_init_sched(); /* needed by module_init stage. */
 763         /* drivers will send hotplug events */
 764         init_workqueues();
 765         usermodehelper_init();
 766         driver_init();
 767         init_irq_proc();
 768         do_initcalls();
 769 }
 770
 771 static int __initdata nosoftlockup;
 772
 773 static int __init nosoftlockup_setup(char *str)
 774 {
 775         nosoftlockup = 1;
 776         return 1;
 777 }
 778 __setup("nosoftlockup", nosoftlockup_setup);
 779
 780 static void __init do_pre_smp_initcalls(void)
 781 {
 782         extern int spawn_ksoftirqd(void);
 783
 784         init_call_single_data();
 785         migration_init();
 786         spawn_ksoftirqd();
 787         if (!nosoftlockup)
 788                 spawn_softlockup_task();
 789 }
 790
 791 static void run_init_process(char *init_filename)
 792 {
 793         argv_init[0] = init_filename;
 794         kernel_execve(init_filename, argv_init, envp_init);
 795 }
 796
 797 /* This is a non __init function. Force it to be noinline otherwise gcc
 798  * makes it inline to init() and it becomes part of init.text section
 799  */
 800 static int noinline init_post(void)
 801 {
 802         free_initmem();
 803         unlock_kernel();
 804         mark_rodata_ro();
 805         system_state = SYSTEM_RUNNING;
 806         numa_default_policy();
 807
 808         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 809                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 810
 811         (void) sys_dup(0);
 812         (void) sys_dup(0);
 813
 814         current->signal->flags |= SIGNAL_UNKILLABLE;
 815
 816         if (ramdisk_execute_command) {
 817                 run_init_process(ramdisk_execute_command);
 818                 printk(KERN_WARNING "Failed to execute %s\n",
 819                                 ramdisk_execute_command);
 820         }
 821
 822         /*
 823          * We try each of these until one succeeds.
 824          *
 825          * The Bourne shell can be used instead of init if we are
 826          * trying to recover a really broken machine.
 827          */
 828         if (execute_command) {
 829                 run_init_process(execute_command);
 830                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 831                                         "defaults...\n", execute_command);
 832         }
 833         run_init_process("/sbin/init");
 834         run_init_process("/etc/init");
 835         run_init_process("/bin/init");
 836         run_init_process("/bin/sh");
 837
 838         panic("No init found.  Try passing init= option to kernel.");
 839 }
 840
 841 static int __init kernel_init(void * unused)
 842 {
 843         lock_kernel();
 844         /*
 845          * init can run on any cpu.
 846          */
 847         set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
 848         /*
 849          * Tell the world that we're going to be the grim
 850          * reaper of innocent orphaned children.
 851          *
 852          * We don't want people to have to make incorrect
 853          * assumptions about where in the task array this
 854          * can be found.
 855          */
 856         init_pid_ns.child_reaper = current;
 857
 858         cad_pid = task_pid(current);
 859
 860         smp_prepare_cpus(setup_max_cpus);
 861
 862         do_pre_smp_initcalls();
 863
 864         smp_init();
 865         sched_init_smp();
 866
 867         cpuset_init_smp();
 868
 869         do_basic_setup();
 870
 871         /*
 872          * check if there is an early userspace init.  If yes, let it do all
 873          * the work
 874          */
 875
 876         if (!ramdisk_execute_command)
 877                 ramdisk_execute_command = "/init";
 878
 879         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 880                 ramdisk_execute_command = NULL;
 881                 prepare_namespace();
 882         }
 883
 884         /*
 885          * Ok, we have completed the initial bootup, and
 886          * we're essentially up and running. Get rid of the
 887          * initmem segments and start the user-mode stuff..
 888          */
 889         init_post();
 890         return 0;
 891 }