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/bootmem.h>
  26 #include <linux/tty.h>
  27 #include <linux/gfp.h>
  28 #include <linux/percpu.h>
  29 #include <linux/kmod.h>
  30 #include <linux/vmalloc.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/page_cgroup.h>
  56 #include <linux/debug_locks.h>
  57 #include <linux/debugobjects.h>
  58 #include <linux/lockdep.h>
  59 #include <linux/pid_namespace.h>
  60 #include <linux/device.h>
  61 #include <linux/kthread.h>
  62 #include <linux/sched.h>
  63 #include <linux/signal.h>
  64 #include <linux/idr.h>
  65 #include <linux/ftrace.h>
  66 #include <trace/boot.h>
  67
  68 #include <asm/io.h>
  69 #include <asm/bugs.h>
  70 #include <asm/setup.h>
  71 #include <asm/sections.h>
  72 #include <asm/cacheflush.h>
  73
  74 #ifdef CONFIG_X86_LOCAL_APIC
  75 #include <asm/smp.h>
  76 #endif
  77
  78 /*
  79  * This is one of the first .c files built. Error out early if we have compiler
  80  * trouble.
  81  */
  82
  83 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
  84 #warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.
  85 #endif
  86
  87 static int kernel_init(void *);
  88
  89 extern void init_IRQ(void);
  90 extern void fork_init(unsigned long);
  91 extern void mca_init(void);
  92 extern void sbus_init(void);
  93 extern void prio_tree_init(void);
  94 extern void radix_tree_init(void);
  95 extern void free_initmem(void);
  96 #ifdef  CONFIG_ACPI
  97 extern void acpi_early_init(void);
  98 #else
  99 static inline void acpi_early_init(void) { }
 100 #endif
 101 #ifndef CONFIG_DEBUG_RODATA
 102 static inline void mark_rodata_ro(void) { }
 103 #endif
 104
 105 #ifdef CONFIG_TC
 106 extern void tc_init(void);
 107 #endif
 108
 109 enum system_states system_state;
 110 EXPORT_SYMBOL(system_state);
 111
 112 /*
 113  * Boot command-line arguments
 114  */
 115 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 116 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 117
 118 extern void time_init(void);
 119 /* Default late time init is NULL. archs can override this later. */
 120 void (*late_time_init)(void);
 121 extern void softirq_init(void);
 122
 123 /* Untouched command line saved by arch-specific code. */
 124 char __initdata boot_command_line[COMMAND_LINE_SIZE];
 125 /* Untouched saved command line (eg. for /proc) */
 126 char *saved_command_line;
 127 /* Command line for parameter parsing */
 128 static char *static_command_line;
 129
 130 static char *execute_command;
 131 static char *ramdisk_execute_command;
 132
 133 #ifdef CONFIG_SMP
 134 /* Setup configured maximum number of CPUs to activate */
 135 unsigned int __initdata setup_max_cpus = NR_CPUS;
 136
 137 /*
 138  * Setup routine for controlling SMP activation
 139  *
 140  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 141  * activation entirely (the MPS table probe still happens, though).
 142  *
 143  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 144  * greater than 0, limits the maximum number of CPUs activated in
 145  * SMP mode to <NUM>.
 146  */
 147 #ifndef CONFIG_X86_IO_APIC
 148 static inline void disable_ioapic_setup(void) {};
 149 #endif
 150
 151 static int __init nosmp(char *str)
 152 {
 153         setup_max_cpus = 0;
 154         disable_ioapic_setup();
 155         return 0;
 156 }
 157
 158 early_param("nosmp", nosmp);
 159
 160 static int __init maxcpus(char *str)
 161 {
 162         get_option(&str, &setup_max_cpus);
 163         if (setup_max_cpus == 0)
 164                 disable_ioapic_setup();
 165
 166         return 0;
 167 }
 168
 169 early_param("maxcpus", maxcpus);
 170 #else
 171 #define setup_max_cpus NR_CPUS
 172 #endif
 173
 174 /*
 175  * If set, this is an indication to the drivers that reset the underlying
 176  * device before going ahead with the initialization otherwise driver might
 177  * rely on the BIOS and skip the reset operation.
 178  *
 179  * This is useful if kernel is booting in an unreliable environment.
 180  * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
 181  * skipped and devices will be in unknown state.
 182  */
 183 unsigned int reset_devices;
 184 EXPORT_SYMBOL(reset_devices);
 185
 186 static int __init set_reset_devices(char *str)
 187 {
 188         reset_devices = 1;
 189         return 1;
 190 }
 191
 192 __setup("reset_devices", set_reset_devices);
 193
 194 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 195 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 196 static const char *panic_later, *panic_param;
 197
 198 extern struct obs_kernel_param __setup_start[], __setup_end[];
 199
 200 static int __init obsolete_checksetup(char *line)
 201 {
 202         struct obs_kernel_param *p;
 203         int had_early_param = 0;
 204
 205         p = __setup_start;
 206         do {
 207                 int n = strlen(p->str);
 208                 if (!strncmp(line, p->str, n)) {
 209                         if (p->early) {
 210                                 /* Already done in parse_early_param?
 211                                  * (Needs exact match on param part).
 212                                  * Keep iterating, as we can have early
 213                                  * params and __setups of same names 8( */
 214                                 if (line[n] == '\0' || line[n] == '=')
 215                                         had_early_param = 1;
 216                         } else if (!p->setup_func) {
 217                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 218                                        " ignored\n", p->str);
 219                                 return 1;
 220                         } else if (p->setup_func(line + n))
 221                                 return 1;
 222                 }
 223                 p++;
 224         } while (p < __setup_end);
 225
 226         return had_early_param;
 227 }
 228
 229 /*
 230  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 231  * still work even if initially too large, it will just take slightly longer
 232  */
 233 unsigned long loops_per_jiffy = (1<<12);
 234
 235 EXPORT_SYMBOL(loops_per_jiffy);
 236
 237 static int __init debug_kernel(char *str)
 238 {
 239         console_loglevel = 10;
 240         return 0;
 241 }
 242
 243 static int __init quiet_kernel(char *str)
 244 {
 245         console_loglevel = 4;
 246         return 0;
 247 }
 248
 249 early_param("debug", debug_kernel);
 250 early_param("quiet", quiet_kernel);
 251
 252 static int __init loglevel(char *str)
 253 {
 254         get_option(&str, &console_loglevel);
 255         return 0;
 256 }
 257
 258 early_param("loglevel", loglevel);
 259
 260 /*
 261  * Unknown boot options get handed to init, unless they look like
 262  * failed parameters
 263  */
 264 static int __init unknown_bootoption(char *param, char *val)
 265 {
 266         /* Change NUL term back to "=", to make "param" the whole string. */
 267         if (val) {
 268                 /* param=val or param="val"? */
 269                 if (val == param+strlen(param)+1)
 270                         val[-1] = '=';
 271                 else if (val == param+strlen(param)+2) {
 272                         val[-2] = '=';
 273                         memmove(val-1, val, strlen(val)+1);
 274                         val--;
 275                 } else
 276                         BUG();
 277         }
 278
 279         /* Handle obsolete-style parameters */
 280         if (obsolete_checksetup(param))
 281                 return 0;
 282
 283         /*
 284          * Preemptive maintenance for "why didn't my misspelled command
 285          * line work?"
 286          */
 287         if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 288                 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 289                 return 0;
 290         }
 291
 292         if (panic_later)
 293                 return 0;
 294
 295         if (val) {
 296                 /* Environment option */
 297                 unsigned int i;
 298                 for (i = 0; envp_init[i]; i++) {
 299                         if (i == MAX_INIT_ENVS) {
 300                                 panic_later = "Too many boot env vars at `%s'";
 301                                 panic_param = param;
 302                         }
 303                         if (!strncmp(param, envp_init[i], val - param))
 304                                 break;
 305                 }
 306                 envp_init[i] = param;
 307         } else {
 308                 /* Command line option */
 309                 unsigned int i;
 310                 for (i = 0; argv_init[i]; i++) {
 311                         if (i == MAX_INIT_ARGS) {
 312                                 panic_later = "Too many boot init vars at `%s'";
 313                                 panic_param = param;
 314                         }
 315                 }
 316                 argv_init[i] = param;
 317         }
 318         return 0;
 319 }
 320
 321 #ifdef CONFIG_DEBUG_PAGEALLOC
 322 int __read_mostly debug_pagealloc_enabled = 0;
 323 #endif
 324
 325 static int __init init_setup(char *str)
 326 {
 327         unsigned int i;
 328
 329         execute_command = str;
 330         /*
 331          * In case LILO is going to boot us with default command line,
 332          * it prepends "auto" before the whole cmdline which makes
 333          * the shell think it should execute a script with such name.
 334          * So we ignore all arguments entered _before_ init=... [MJ]
 335          */
 336         for (i = 1; i < MAX_INIT_ARGS; i++)
 337                 argv_init[i] = NULL;
 338         return 1;
 339 }
 340 __setup("init=", init_setup);
 341
 342 static int __init rdinit_setup(char *str)
 343 {
 344         unsigned int i;
 345
 346         ramdisk_execute_command = str;
 347         /* See "auto" comment in init_setup */
 348         for (i = 1; i < MAX_INIT_ARGS; i++)
 349                 argv_init[i] = NULL;
 350         return 1;
 351 }
 352 __setup("rdinit=", rdinit_setup);
 353
 354 #ifndef CONFIG_SMP
 355
 356 #ifdef CONFIG_X86_LOCAL_APIC
 357 static void __init smp_init(void)
 358 {
 359         APIC_init_uniprocessor();
 360 }
 361 #else
 362 #define smp_init()      do { } while (0)
 363 #endif
 364
 365 static inline void setup_per_cpu_areas(void) { }
 366 static inline void setup_nr_cpu_ids(void) { }
 367 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 368
 369 #else
 370
 371 #if NR_CPUS > BITS_PER_LONG
 372 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
 373 EXPORT_SYMBOL(cpu_mask_all);
 374 #endif
 375
 376 /* Setup number of possible processor ids */
 377 int nr_cpu_ids __read_mostly = NR_CPUS;
 378 EXPORT_SYMBOL(nr_cpu_ids);
 379
 380 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 381 static void __init setup_nr_cpu_ids(void)
 382 {
 383         nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 384 }
 385
 386 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
 387 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 388
 389 EXPORT_SYMBOL(__per_cpu_offset);
 390
 391 static void __init setup_per_cpu_areas(void)
 392 {
 393         unsigned long size, i;
 394         char *ptr;
 395         unsigned long nr_possible_cpus = num_possible_cpus();
 396
 397         /* Copy section for each CPU (we discard the original) */
 398         size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
 399         ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 400
 401         for_each_possible_cpu(i) {
 402                 __per_cpu_offset[i] = ptr - __per_cpu_start;
 403                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 404                 ptr += size;
 405         }
 406 }
 407 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
 408
 409 /* Called by boot processor to activate the rest. */
 410 static void __init smp_init(void)
 411 {
 412         unsigned int cpu;
 413
 414         /*
 415          * Set up the current CPU as possible to migrate to.
 416          * The other ones will be done by cpu_up/cpu_down()
 417          */
 418         cpu = smp_processor_id();
 419         cpu_set(cpu, cpu_active_map);
 420
 421         /* FIXME: This should be done in userspace --RR */
 422         for_each_present_cpu(cpu) {
 423                 if (num_online_cpus() >= setup_max_cpus)
 424                         break;
 425                 if (!cpu_online(cpu))
 426                         cpu_up(cpu);
 427         }
 428
 429         /* Any cleanup work */
 430         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 431         smp_cpus_done(setup_max_cpus);
 432 }
 433
 434 #endif
 435
 436 /*
 437  * We need to store the untouched command line for future reference.
 438  * We also need to store the touched command line since the parameter
 439  * parsing is performed in place, and we should allow a component to
 440  * store reference of name/value for future reference.
 441  */
 442 static void __init setup_command_line(char *command_line)
 443 {
 444         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 445         static_command_line = alloc_bootmem(strlen (command_line)+1);
 446         strcpy (saved_command_line, boot_command_line);
 447         strcpy (static_command_line, command_line);
 448 }
 449
 450 /*
 451  * We need to finalize in a non-__init function or else race conditions
 452  * between the root thread and the init thread may cause start_kernel to
 453  * be reaped by free_initmem before the root thread has proceeded to
 454  * cpu_idle.
 455  *
 456  * gcc-3.4 accidentally inlines this function, so use noinline.
 457  */
 458
 459 static void noinline __init_refok rest_init(void)
 460         __releases(kernel_lock)
 461 {
 462         int pid;
 463
 464         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 465         numa_default_policy();
 466         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 467         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 468         unlock_kernel();
 469
 470         /*
 471          * The boot idle thread must execute schedule()
 472          * at least once to get things moving:
 473          */
 474         init_idle_bootup_task(current);
 475         preempt_enable_no_resched();
 476         schedule();
 477         preempt_disable();
 478
 479         /* Call into cpu_idle with preempt disabled */
 480         cpu_idle();
 481 }
 482
 483 /* Check for early params. */
 484 static int __init do_early_param(char *param, char *val)
 485 {
 486         struct obs_kernel_param *p;
 487
 488         for (p = __setup_start; p < __setup_end; p++) {
 489                 if ((p->early && strcmp(param, p->str) == 0) ||
 490                     (strcmp(param, "console") == 0 &&
 491                      strcmp(p->str, "earlycon") == 0)
 492                 ) {
 493                         if (p->setup_func(val) != 0)
 494                                 printk(KERN_WARNING
 495                                        "Malformed early option '%s'\n", param);
 496                 }
 497         }
 498         /* We accept everything at this stage. */
 499         return 0;
 500 }
 501
 502 /* Arch code calls this early on, or if not, just before other parsing. */
 503 void __init parse_early_param(void)
 504 {
 505         static __initdata int done = 0;
 506         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 507
 508         if (done)
 509                 return;
 510
 511         /* All fall through to do_early_param. */
 512         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 513         parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 514         done = 1;
 515 }
 516
 517 /*
 518  *      Activate the first processor.
 519  */
 520
 521 static void __init boot_cpu_init(void)
 522 {
 523         int cpu = smp_processor_id();
 524         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 525         set_cpu_online(cpu, true);
 526         set_cpu_present(cpu, true);
 527         set_cpu_possible(cpu, true);
 528 }
 529
 530 void __init __weak smp_setup_processor_id(void)
 531 {
 532 }
 533
 534 void __init __weak thread_info_cache_init(void)
 535 {
 536 }
 537
 538 void __init __weak arch_early_irq_init(void)
 539 {
 540 }
 541
 542 void __init __weak early_irq_init(void)
 543 {
 544         arch_early_irq_init();
 545 }
 546
 547 asmlinkage void __init start_kernel(void)
 548 {
 549         char * command_line;
 550         extern struct kernel_param __start___param[], __stop___param[];
 551
 552         smp_setup_processor_id();
 553
 554         /*
 555          * Need to run as early as possible, to initialize the
 556          * lockdep hash:
 557          */
 558         unwind_init();
 559         lockdep_init();
 560         debug_objects_early_init();
 561         cgroup_init_early();
 562
 563         local_irq_disable();
 564         early_boot_irqs_off();
 565         early_init_irq_lock_class();
 566
 567 /*
 568  * Interrupts are still disabled. Do necessary setups, then
 569  * enable them
 570  */
 571         lock_kernel();
 572         tick_init();
 573         boot_cpu_init();
 574         page_address_init();
 575         printk(KERN_NOTICE);
 576         printk(linux_banner);
 577         setup_arch(&command_line);
 578         mm_init_owner(&init_mm, &init_task);
 579         setup_command_line(command_line);
 580         unwind_setup();
 581         setup_per_cpu_areas();
 582         setup_nr_cpu_ids();
 583         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 584
 585         /*
 586          * Set up the scheduler prior starting any interrupts (such as the
 587          * timer interrupt). Full topology setup happens at smp_init()
 588          * time - but meanwhile we still have a functioning scheduler.
 589          */
 590         sched_init();
 591         /*
 592          * Disable preemption - early bootup scheduling is extremely
 593          * fragile until we cpu_idle() for the first time.
 594          */
 595         preempt_disable();
 596         build_all_zonelists();
 597         page_alloc_init();
 598         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 599         parse_early_param();
 600         parse_args("Booting kernel", static_command_line, __start___param,
 601                    __stop___param - __start___param,
 602                    &unknown_bootoption);
 603         if (!irqs_disabled()) {
 604                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 605                                 "enabled *very* early, fixing it\n");
 606                 local_irq_disable();
 607         }
 608         sort_main_extable();
 609         trap_init();
 610         rcu_init();
 611         /* init some links before init_ISA_irqs() */
 612         early_irq_init();
 613         init_IRQ();
 614         pidhash_init();
 615         init_timers();
 616         hrtimers_init();
 617         softirq_init();
 618         timekeeping_init();
 619         time_init();
 620         sched_clock_init();
 621         profile_init();
 622         if (!irqs_disabled())
 623                 printk("start_kernel(): bug: interrupts were enabled early\n");
 624         early_boot_irqs_on();
 625         local_irq_enable();
 626
 627         /*
 628          * HACK ALERT! This is early. We're enabling the console before
 629          * we've done PCI setups etc, and console_init() must be aware of
 630          * this. But we do want output early, in case something goes wrong.
 631          */
 632         console_init();
 633         if (panic_later)
 634                 panic(panic_later, panic_param);
 635
 636         lockdep_info();
 637
 638         /*
 639          * Need to run this when irqs are enabled, because it wants
 640          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 641          * too:
 642          */
 643         locking_selftest();
 644
 645 #ifdef CONFIG_BLK_DEV_INITRD
 646         if (initrd_start && !initrd_below_start_ok &&
 647             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 648                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 649                     "disabling it.\n",
 650                     page_to_pfn(virt_to_page((void *)initrd_start)),
 651                     min_low_pfn);
 652                 initrd_start = 0;
 653         }
 654 #endif
 655         vmalloc_init();
 656         vfs_caches_init_early();
 657         cpuset_init_early();
 658         page_cgroup_init();
 659         mem_init();
 660         enable_debug_pagealloc();
 661         cpu_hotplug_init();
 662         kmem_cache_init();
 663         debug_objects_mem_init();
 664         idr_init_cache();
 665         setup_per_cpu_pageset();
 666         numa_policy_init();
 667         if (late_time_init)
 668                 late_time_init();
 669         calibrate_delay();
 670         pidmap_init();
 671         pgtable_cache_init();
 672         prio_tree_init();
 673         anon_vma_init();
 674 #ifdef CONFIG_X86
 675         if (efi_enabled)
 676                 efi_enter_virtual_mode();
 677 #endif
 678         thread_info_cache_init();
 679         cred_init();
 680         fork_init(num_physpages);
 681         proc_caches_init();
 682         buffer_init();
 683         key_init();
 684         security_init();
 685         vfs_caches_init(num_physpages);
 686         radix_tree_init();
 687         signals_init();
 688         /* rootfs populating might need page-writeback */
 689         page_writeback_init();
 690 #ifdef CONFIG_PROC_FS
 691         proc_root_init();
 692 #endif
 693         cgroup_init();
 694         cpuset_init();
 695         taskstats_init_early();
 696         delayacct_init();
 697
 698         check_bugs();
 699
 700         acpi_early_init(); /* before LAPIC and SMP init */
 701
 702         ftrace_init();
 703
 704         /* Do the rest non-__init'ed, we're now alive */
 705         rest_init();
 706 }
 707
 708 static int initcall_debug;
 709 core_param(initcall_debug, initcall_debug, bool, 0644);
 710
 711 int do_one_initcall(initcall_t fn)
 712 {
 713         int count = preempt_count();
 714         ktime_t calltime, delta, rettime;
 715         char msgbuf[64];
 716         struct boot_trace_call call;
 717         struct boot_trace_ret ret;
 718
 719         if (initcall_debug) {
 720                 call.caller = task_pid_nr(current);
 721                 printk("calling  %pF @ %i\n", fn, call.caller);
 722                 calltime = ktime_get();
 723                 trace_boot_call(&call, fn);
 724                 enable_boot_trace();
 725         }
 726
 727         ret.result = fn();
 728
 729         if (initcall_debug) {
 730                 disable_boot_trace();
 731                 rettime = ktime_get();
 732                 delta = ktime_sub(rettime, calltime);
 733                 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 734                 trace_boot_ret(&ret, fn);
 735                 printk("initcall %pF returned %d after %Ld usecs\n", fn,
 736                         ret.result, ret.duration);
 737         }
 738
 739         msgbuf[0] = 0;
 740
 741         if (ret.result && ret.result != -ENODEV && initcall_debug)
 742                 sprintf(msgbuf, "error code %d ", ret.result);
 743
 744         if (preempt_count() != count) {
 745                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 746                 preempt_count() = count;
 747         }
 748         if (irqs_disabled()) {
 749                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 750                 local_irq_enable();
 751         }
 752         if (msgbuf[0]) {
 753                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 754         }
 755
 756         return ret.result;
 757 }
 758
 759
 760 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
 761
 762 static void __init do_initcalls(void)
 763 {
 764         initcall_t *call;
 765
 766         for (call = __early_initcall_end; call < __initcall_end; call++)
 767                 do_one_initcall(*call);
 768
 769         /* Make sure there is no pending stuff from the initcall sequence */
 770         flush_scheduled_work();
 771 }
 772
 773 /*
 774  * Ok, the machine is now initialized. None of the devices
 775  * have been touched yet, but the CPU subsystem is up and
 776  * running, and memory and process management works.
 777  *
 778  * Now we can finally start doing some real work..
 779  */
 780 static void __init do_basic_setup(void)
 781 {
 782         rcu_init_sched(); /* needed by module_init stage. */
 783         init_workqueues();
 784         usermodehelper_init();
 785         driver_init();
 786         init_irq_proc();
 787         do_initcalls();
 788 }
 789
 790 static void __init do_pre_smp_initcalls(void)
 791 {
 792         initcall_t *call;
 793
 794         for (call = __initcall_start; call < __early_initcall_end; call++)
 795                 do_one_initcall(*call);
 796 }
 797
 798 static void run_init_process(char *init_filename)
 799 {
 800         argv_init[0] = init_filename;
 801         kernel_execve(init_filename, argv_init, envp_init);
 802 }
 803
 804 /* This is a non __init function. Force it to be noinline otherwise gcc
 805  * makes it inline to init() and it becomes part of init.text section
 806  */
 807 static int noinline init_post(void)
 808 {
 809         free_initmem();
 810         unlock_kernel();
 811         mark_rodata_ro();
 812         system_state = SYSTEM_RUNNING;
 813         numa_default_policy();
 814
 815         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 816                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 817
 818         (void) sys_dup(0);
 819         (void) sys_dup(0);
 820
 821         current->signal->flags |= SIGNAL_UNKILLABLE;
 822
 823         if (ramdisk_execute_command) {
 824                 run_init_process(ramdisk_execute_command);
 825                 printk(KERN_WARNING "Failed to execute %s\n",
 826                                 ramdisk_execute_command);
 827         }
 828
 829         /*
 830          * We try each of these until one succeeds.
 831          *
 832          * The Bourne shell can be used instead of init if we are
 833          * trying to recover a really broken machine.
 834          */
 835         if (execute_command) {
 836                 run_init_process(execute_command);
 837                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 838                                         "defaults...\n", execute_command);
 839         }
 840         run_init_process("/sbin/init");
 841         run_init_process("/etc/init");
 842         run_init_process("/bin/init");
 843         run_init_process("/bin/sh");
 844
 845         panic("No init found.  Try passing init= option to kernel.");
 846 }
 847
 848 static int __init kernel_init(void * unused)
 849 {
 850         lock_kernel();
 851         /*
 852          * init can run on any cpu.
 853          */
 854         set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
 855         /*
 856          * Tell the world that we're going to be the grim
 857          * reaper of innocent orphaned children.
 858          *
 859          * We don't want people to have to make incorrect
 860          * assumptions about where in the task array this
 861          * can be found.
 862          */
 863         init_pid_ns.child_reaper = current;
 864
 865         cad_pid = task_pid(current);
 866
 867         smp_prepare_cpus(setup_max_cpus);
 868
 869         do_pre_smp_initcalls();
 870         start_boot_trace();
 871
 872         smp_init();
 873         sched_init_smp();
 874
 875         cpuset_init_smp();
 876
 877         do_basic_setup();
 878
 879         /*
 880          * check if there is an early userspace init.  If yes, let it do all
 881          * the work
 882          */
 883
 884         if (!ramdisk_execute_command)
 885                 ramdisk_execute_command = "/init";
 886
 887         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 888                 ramdisk_execute_command = NULL;
 889                 prepare_namespace();
 890         }
 891
 892         /*
 893          * Ok, we have completed the initial bootup, and
 894          * we're essentially up and running. Get rid of the
 895          * initmem segments and start the user-mode stuff..
 896          */
 897
 898         init_post();
 899         return 0;
 900 }