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