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  * failed parameters
 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         /*
 276          * Preemptive maintenance for "why didn't my misspelled command
 277          * line work?"
 278          */
 279         if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 280                 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 281                 return 0;
 282         }
 283
 284         if (panic_later)
 285                 return 0;
 286
 287         if (val) {
 288                 /* Environment option */
 289                 unsigned int i;
 290                 for (i = 0; envp_init[i]; i++) {
 291                         if (i == MAX_INIT_ENVS) {
 292                                 panic_later = "Too many boot env vars at `%s'";
 293                                 panic_param = param;
 294                         }
 295                         if (!strncmp(param, envp_init[i], val - param))
 296                                 break;
 297                 }
 298                 envp_init[i] = param;
 299         } else {
 300                 /* Command line option */
 301                 unsigned int i;
 302                 for (i = 0; argv_init[i]; i++) {
 303                         if (i == MAX_INIT_ARGS) {
 304                                 panic_later = "Too many boot init vars at `%s'";
 305                                 panic_param = param;
 306                         }
 307                 }
 308                 argv_init[i] = param;
 309         }
 310         return 0;
 311 }
 312
 313 #ifdef CONFIG_DEBUG_PAGEALLOC
 314 int __read_mostly debug_pagealloc_enabled = 0;
 315 #endif
 316
 317 static int __init init_setup(char *str)
 318 {
 319         unsigned int i;
 320
 321         execute_command = str;
 322         /*
 323          * In case LILO is going to boot us with default command line,
 324          * it prepends "auto" before the whole cmdline which makes
 325          * the shell think it should execute a script with such name.
 326          * So we ignore all arguments entered _before_ init=... [MJ]
 327          */
 328         for (i = 1; i < MAX_INIT_ARGS; i++)
 329                 argv_init[i] = NULL;
 330         return 1;
 331 }
 332 __setup("init=", init_setup);
 333
 334 static int __init rdinit_setup(char *str)
 335 {
 336         unsigned int i;
 337
 338         ramdisk_execute_command = str;
 339         /* See "auto" comment in init_setup */
 340         for (i = 1; i < MAX_INIT_ARGS; i++)
 341                 argv_init[i] = NULL;
 342         return 1;
 343 }
 344 __setup("rdinit=", rdinit_setup);
 345
 346 #ifndef CONFIG_SMP
 347
 348 #ifdef CONFIG_X86_LOCAL_APIC
 349 static void __init smp_init(void)
 350 {
 351         APIC_init_uniprocessor();
 352 }
 353 #else
 354 #define smp_init()      do { } while (0)
 355 #endif
 356
 357 static inline void setup_nr_cpu_ids(void) { }
 358 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 359
 360 #else
 361
 362 /* Setup number of possible processor ids */
 363 int nr_cpu_ids __read_mostly = NR_CPUS;
 364 EXPORT_SYMBOL(nr_cpu_ids);
 365
 366 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 367 static void __init setup_nr_cpu_ids(void)
 368 {
 369         nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 370 }
 371
 372 /* Called by boot processor to activate the rest. */
 373 static void __init smp_init(void)
 374 {
 375         unsigned int cpu;
 376
 377         /*
 378          * Set up the current CPU as possible to migrate to.
 379          * The other ones will be done by cpu_up/cpu_down()
 380          */
 381         set_cpu_active(smp_processor_id(), true);
 382
 383         /* FIXME: This should be done in userspace --RR */
 384         for_each_present_cpu(cpu) {
 385                 if (num_online_cpus() >= setup_max_cpus)
 386                         break;
 387                 if (!cpu_online(cpu))
 388                         cpu_up(cpu);
 389         }
 390
 391         /* Any cleanup work */
 392         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 393         smp_cpus_done(setup_max_cpus);
 394 }
 395
 396 #endif
 397
 398 /*
 399  * We need to store the untouched command line for future reference.
 400  * We also need to store the touched command line since the parameter
 401  * parsing is performed in place, and we should allow a component to
 402  * store reference of name/value for future reference.
 403  */
 404 static void __init setup_command_line(char *command_line)
 405 {
 406         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 407         static_command_line = alloc_bootmem(strlen (command_line)+1);
 408         strcpy (saved_command_line, boot_command_line);
 409         strcpy (static_command_line, command_line);
 410 }
 411
 412 /*
 413  * We need to finalize in a non-__init function or else race conditions
 414  * between the root thread and the init thread may cause start_kernel to
 415  * be reaped by free_initmem before the root thread has proceeded to
 416  * cpu_idle.
 417  *
 418  * gcc-3.4 accidentally inlines this function, so use noinline.
 419  */
 420
 421 static noinline void __init_refok rest_init(void)
 422         __releases(kernel_lock)
 423 {
 424         int pid;
 425
 426         rcu_scheduler_starting();
 427         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 428         numa_default_policy();
 429         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 430         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 431         unlock_kernel();
 432
 433         /*
 434          * The boot idle thread must execute schedule()
 435          * at least once to get things moving:
 436          */
 437         init_idle_bootup_task(current);
 438         preempt_enable_no_resched();
 439         schedule();
 440         preempt_disable();
 441
 442         /* Call into cpu_idle with preempt disabled */
 443         cpu_idle();
 444 }
 445
 446 /* Check for early params. */
 447 static int __init do_early_param(char *param, char *val)
 448 {
 449         struct obs_kernel_param *p;
 450
 451         for (p = __setup_start; p < __setup_end; p++) {
 452                 if ((p->early && strcmp(param, p->str) == 0) ||
 453                     (strcmp(param, "console") == 0 &&
 454                      strcmp(p->str, "earlycon") == 0)
 455                 ) {
 456                         if (p->setup_func(val) != 0)
 457                                 printk(KERN_WARNING
 458                                        "Malformed early option '%s'\n", param);
 459                 }
 460         }
 461         /* We accept everything at this stage. */
 462         return 0;
 463 }
 464
 465 void __init parse_early_options(char *cmdline)
 466 {
 467         parse_args("early options", cmdline, NULL, 0, do_early_param);
 468 }
 469
 470 /* Arch code calls this early on, or if not, just before other parsing. */
 471 void __init parse_early_param(void)
 472 {
 473         static __initdata int done = 0;
 474         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 475
 476         if (done)
 477                 return;
 478
 479         /* All fall through to do_early_param. */
 480         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 481         parse_early_options(tmp_cmdline);
 482         done = 1;
 483 }
 484
 485 /*
 486  *      Activate the first processor.
 487  */
 488
 489 static void __init boot_cpu_init(void)
 490 {
 491         int cpu = smp_processor_id();
 492         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 493         set_cpu_online(cpu, true);
 494         set_cpu_present(cpu, true);
 495         set_cpu_possible(cpu, true);
 496 }
 497
 498 void __init __weak smp_setup_processor_id(void)
 499 {
 500 }
 501
 502 void __init __weak thread_info_cache_init(void)
 503 {
 504 }
 505
 506 /*
 507  * Set up kernel memory allocators
 508  */
 509 static void __init mm_init(void)
 510 {
 511         /*
 512          * page_cgroup requires countinous pages as memmap
 513          * and it's bigger than MAX_ORDER unless SPARSEMEM.
 514          */
 515         page_cgroup_init_flatmem();
 516         mem_init();
 517         kmem_cache_init();
 518         pgtable_cache_init();
 519         vmalloc_init();
 520 }
 521
 522 asmlinkage void __init start_kernel(void)
 523 {
 524         char * command_line;
 525         extern struct kernel_param __start___param[], __stop___param[];
 526
 527         smp_setup_processor_id();
 528
 529         /*
 530          * Need to run as early as possible, to initialize the
 531          * lockdep hash:
 532          */
 533         lockdep_init();
 534         debug_objects_early_init();
 535
 536         /*
 537          * Set up the the initial canary ASAP:
 538          */
 539         boot_init_stack_canary();
 540
 541         cgroup_init_early();
 542
 543         local_irq_disable();
 544         early_boot_irqs_off();
 545         early_init_irq_lock_class();
 546
 547 /*
 548  * Interrupts are still disabled. Do necessary setups, then
 549  * enable them
 550  */
 551         lock_kernel();
 552         tick_init();
 553         boot_cpu_init();
 554         page_address_init();
 555         printk(KERN_NOTICE "%s", linux_banner);
 556         setup_arch(&command_line);
 557         mm_init_owner(&init_mm, &init_task);
 558         setup_command_line(command_line);
 559         setup_nr_cpu_ids();
 560         setup_per_cpu_areas();
 561         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 562
 563         build_all_zonelists();
 564         page_alloc_init();
 565
 566         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 567         parse_early_param();
 568         parse_args("Booting kernel", static_command_line, __start___param,
 569                    __stop___param - __start___param,
 570                    &unknown_bootoption);
 571         /*
 572          * These use large bootmem allocations and must precede
 573          * kmem_cache_init()
 574          */
 575         pidhash_init();
 576         vfs_caches_init_early();
 577         sort_main_extable();
 578         trap_init();
 579         mm_init();
 580         /*
 581          * Set up the scheduler prior starting any interrupts (such as the
 582          * timer interrupt). Full topology setup happens at smp_init()
 583          * time - but meanwhile we still have a functioning scheduler.
 584          */
 585         sched_init();
 586         /*
 587          * Disable preemption - early bootup scheduling is extremely
 588          * fragile until we cpu_idle() for the first time.
 589          */
 590         preempt_disable();
 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         rcu_init();
 597         /* init some links before init_ISA_irqs() */
 598         early_irq_init();
 599         init_IRQ();
 600         prio_tree_init();
 601         init_timers();
 602         hrtimers_init();
 603         softirq_init();
 604         timekeeping_init();
 605         time_init();
 606         profile_init();
 607         if (!irqs_disabled())
 608                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
 609                                  "enabled early\n");
 610         early_boot_irqs_on();
 611         local_irq_enable();
 612
 613         /* Interrupts are enabled now so all GFP allocations are safe. */
 614         set_gfp_allowed_mask(__GFP_BITS_MASK);
 615
 616         kmem_cache_init_late();
 617
 618         /*
 619          * HACK ALERT! This is early. We're enabling the console before
 620          * we've done PCI setups etc, and console_init() must be aware of
 621          * this. But we do want output early, in case something goes wrong.
 622          */
 623         console_init();
 624         if (panic_later)
 625                 panic(panic_later, panic_param);
 626
 627         lockdep_info();
 628
 629         /*
 630          * Need to run this when irqs are enabled, because it wants
 631          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 632          * too:
 633          */
 634         locking_selftest();
 635
 636 #ifdef CONFIG_BLK_DEV_INITRD
 637         if (initrd_start && !initrd_below_start_ok &&
 638             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 639                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 640                     "disabling it.\n",
 641                     page_to_pfn(virt_to_page((void *)initrd_start)),
 642                     min_low_pfn);
 643                 initrd_start = 0;
 644         }
 645 #endif
 646         page_cgroup_init();
 647         enable_debug_pagealloc();
 648         kmemtrace_init();
 649         kmemleak_init();
 650         debug_objects_mem_init();
 651         idr_init_cache();
 652         setup_per_cpu_pageset();
 653         numa_policy_init();
 654         if (late_time_init)
 655                 late_time_init();
 656         sched_clock_init();
 657         calibrate_delay();
 658         pidmap_init();
 659         anon_vma_init();
 660 #ifdef CONFIG_X86
 661         if (efi_enabled)
 662                 efi_enter_virtual_mode();
 663 #endif
 664         thread_info_cache_init();
 665         cred_init();
 666         fork_init(totalram_pages);
 667         proc_caches_init();
 668         buffer_init();
 669         key_init();
 670         security_init();
 671         vfs_caches_init(totalram_pages);
 672         radix_tree_init();
 673         signals_init();
 674         /* rootfs populating might need page-writeback */
 675         page_writeback_init();
 676 #ifdef CONFIG_PROC_FS
 677         proc_root_init();
 678 #endif
 679         cgroup_init();
 680         cpuset_init();
 681         taskstats_init_early();
 682         delayacct_init();
 683
 684         check_bugs();
 685
 686         acpi_early_init(); /* before LAPIC and SMP init */
 687         sfi_init_late();
 688
 689         ftrace_init();
 690
 691         /* Do the rest non-__init'ed, we're now alive */
 692         rest_init();
 693 }
 694
 695 /* Call all constructor functions linked into the kernel. */
 696 static void __init do_ctors(void)
 697 {
 698 #ifdef CONFIG_CONSTRUCTORS
 699         ctor_fn_t *call = (ctor_fn_t *) __ctors_start;
 700
 701         for (; call < (ctor_fn_t *) __ctors_end; call++)
 702                 (*call)();
 703 #endif
 704 }
 705
 706 int initcall_debug;
 707 core_param(initcall_debug, initcall_debug, bool, 0644);
 708
 709 static char msgbuf[64];
 710 static struct boot_trace_call call;
 711 static struct boot_trace_ret ret;
 712
 713 int do_one_initcall(initcall_t fn)
 714 {
 715         int count = preempt_count();
 716         ktime_t calltime, delta, rettime;
 717
 718         if (initcall_debug) {
 719                 call.caller = task_pid_nr(current);
 720                 printk("calling  %pF @ %i\n", fn, call.caller);
 721                 calltime = ktime_get();
 722                 trace_boot_call(&call, fn);
 723                 enable_boot_trace();
 724         }
 725
 726         ret.result = fn();
 727
 728         if (initcall_debug) {
 729                 disable_boot_trace();
 730                 rettime = ktime_get();
 731                 delta = ktime_sub(rettime, calltime);
 732                 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 733                 trace_boot_ret(&ret, fn);
 734                 printk("initcall %pF returned %d after %Ld usecs\n", fn,
 735                         ret.result, ret.duration);
 736         }
 737
 738         msgbuf[0] = 0;
 739
 740         if (ret.result && ret.result != -ENODEV && initcall_debug)
 741                 sprintf(msgbuf, "error code %d ", ret.result);
 742
 743         if (preempt_count() != count) {
 744                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 745                 preempt_count() = count;
 746         }
 747         if (irqs_disabled()) {
 748                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 749                 local_irq_enable();
 750         }
 751         if (msgbuf[0]) {
 752                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 753         }
 754
 755         return ret.result;
 756 }
 757
 758
 759 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
 760
 761 static void __init do_initcalls(void)
 762 {
 763         initcall_t *call;
 764
 765         for (call = __early_initcall_end; call < __initcall_end; call++)
 766                 do_one_initcall(*call);
 767
 768         /* Make sure there is no pending stuff from the initcall sequence */
 769         flush_scheduled_work();
 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         init_workqueues();
 782         cpuset_init_smp();
 783         usermodehelper_init();
 784         init_tmpfs();
 785         driver_init();
 786         init_irq_proc();
 787         do_ctors();
 788         do_initcalls();
 789 }
 790
 791 static void __init do_pre_smp_initcalls(void)
 792 {
 793         initcall_t *call;
 794
 795         for (call = __initcall_start; call < __early_initcall_end; call++)
 796                 do_one_initcall(*call);
 797 }
 798
 799 static void run_init_process(char *init_filename)
 800 {
 801         argv_init[0] = init_filename;
 802         kernel_execve(init_filename, argv_init, envp_init);
 803 }
 804
 805 /* This is a non __init function. Force it to be noinline otherwise gcc
 806  * makes it inline to init() and it becomes part of init.text section
 807  */
 808 static noinline int init_post(void)
 809         __releases(kernel_lock)
 810 {
 811         /* need to finish all async __init code before freeing the memory */
 812         async_synchronize_full();
 813         free_initmem();
 814         unlock_kernel();
 815         mark_rodata_ro();
 816         system_state = SYSTEM_RUNNING;
 817         numa_default_policy();
 818
 819         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 820                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 821
 822         (void) sys_dup(0);
 823         (void) sys_dup(0);
 824
 825         current->signal->flags |= SIGNAL_UNKILLABLE;
 826
 827         if (ramdisk_execute_command) {
 828                 run_init_process(ramdisk_execute_command);
 829                 printk(KERN_WARNING "Failed to execute %s\n",
 830                                 ramdisk_execute_command);
 831         }
 832
 833         /*
 834          * We try each of these until one succeeds.
 835          *
 836          * The Bourne shell can be used instead of init if we are
 837          * trying to recover a really broken machine.
 838          */
 839         if (execute_command) {
 840                 run_init_process(execute_command);
 841                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 842                                         "defaults...\n", execute_command);
 843         }
 844         run_init_process("/sbin/init");
 845         run_init_process("/etc/init");
 846         run_init_process("/bin/init");
 847         run_init_process("/bin/sh");
 848
 849         panic("No init found.  Try passing init= option to kernel.");
 850 }
 851
 852 static int __init kernel_init(void * unused)
 853 {
 854         lock_kernel();
 855
 856         /*
 857          * init can allocate pages on any node
 858          */
 859         set_mems_allowed(node_possible_map);
 860         /*
 861          * init can run on any cpu.
 862          */
 863         set_cpus_allowed_ptr(current, cpu_all_mask);
 864         /*
 865          * Tell the world that we're going to be the grim
 866          * reaper of innocent orphaned children.
 867          *
 868          * We don't want people to have to make incorrect
 869          * assumptions about where in the task array this
 870          * can be found.
 871          */
 872         init_pid_ns.child_reaper = current;
 873
 874         cad_pid = task_pid(current);
 875
 876         smp_prepare_cpus(setup_max_cpus);
 877
 878         do_pre_smp_initcalls();
 879         start_boot_trace();
 880
 881         smp_init();
 882         sched_init_smp();
 883
 884         do_basic_setup();
 885
 886         /*
 887          * check if there is an early userspace init.  If yes, let it do all
 888          * the work
 889          */
 890
 891         if (!ramdisk_execute_command)
 892                 ramdisk_execute_command = "/init";
 893
 894         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 895                 ramdisk_execute_command = NULL;
 896                 prepare_namespace();
 897         }
 898
 899         /*
 900          * Ok, we have completed the initial bootup, and
 901          * we're essentially up and running. Get rid of the
 902          * initmem segments and start the user-mode stuff..
 903          */
 904
 905         init_post();
 906         return 0;
 907 }