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 static int kernel_init(void *);
  79
  80 extern void init_IRQ(void);
  81 extern void fork_init(unsigned long);
  82 extern void mca_init(void);
  83 extern void sbus_init(void);
  84 extern void prio_tree_init(void);
  85 extern void radix_tree_init(void);
  86 extern void free_initmem(void);
  87 #ifdef  CONFIG_ACPI
  88 extern void acpi_early_init(void);
  89 #else
  90 static inline void acpi_early_init(void) { }
  91 #endif
  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;
 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 (*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 #ifndef CONFIG_X86_IO_APIC
 139 static inline void disable_ioapic_setup(void) {};
 140 #endif
 141
 142 static int __init nosmp(char *str)
 143 {
 144         setup_max_cpus = 0;
 145         disable_ioapic_setup();
 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                 disable_ioapic_setup();
 156
 157         return 0;
 158 }
 159
 160 early_param("maxcpus", maxcpus);
 161 #else
 162 #define 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_per_cpu_areas(void) { }
 357 static inline void setup_nr_cpu_ids(void) { }
 358 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 359
 360 #else
 361
 362 #if NR_CPUS > BITS_PER_LONG
 363 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
 364 EXPORT_SYMBOL(cpu_mask_all);
 365 #endif
 366
 367 /* Setup number of possible processor ids */
 368 int nr_cpu_ids __read_mostly = NR_CPUS;
 369 EXPORT_SYMBOL(nr_cpu_ids);
 370
 371 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
 372 static void __init setup_nr_cpu_ids(void)
 373 {
 374         int cpu, highest_cpu = 0;
 375
 376         for_each_possible_cpu(cpu)
 377                 highest_cpu = cpu;
 378
 379         nr_cpu_ids = highest_cpu + 1;
 380 }
 381
 382 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
 383 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
 384
 385 EXPORT_SYMBOL(__per_cpu_offset);
 386
 387 static void __init setup_per_cpu_areas(void)
 388 {
 389         unsigned long size, i;
 390         char *ptr;
 391         unsigned long nr_possible_cpus = num_possible_cpus();
 392
 393         /* Copy section for each CPU (we discard the original) */
 394         size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
 395         ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 396
 397         for_each_possible_cpu(i) {
 398                 __per_cpu_offset[i] = ptr - __per_cpu_start;
 399                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 400                 ptr += size;
 401         }
 402 }
 403 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
 404
 405 /* Called by boot processor to activate the rest. */
 406 static void __init smp_init(void)
 407 {
 408         unsigned int cpu;
 409
 410         /*
 411          * Set up the current CPU as possible to migrate to.
 412          * The other ones will be done by cpu_up/cpu_down()
 413          */
 414         cpu = smp_processor_id();
 415         cpu_set(cpu, cpu_active_map);
 416
 417         /* FIXME: This should be done in userspace --RR */
 418         for_each_present_cpu(cpu) {
 419                 if (num_online_cpus() >= setup_max_cpus)
 420                         break;
 421                 if (!cpu_online(cpu))
 422                         cpu_up(cpu);
 423         }
 424
 425         /* Any cleanup work */
 426         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 427         smp_cpus_done(setup_max_cpus);
 428 }
 429
 430 #endif
 431
 432 /*
 433  * We need to store the untouched command line for future reference.
 434  * We also need to store the touched command line since the parameter
 435  * parsing is performed in place, and we should allow a component to
 436  * store reference of name/value for future reference.
 437  */
 438 static void __init setup_command_line(char *command_line)
 439 {
 440         saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
 441         static_command_line = alloc_bootmem(strlen (command_line)+1);
 442         strcpy (saved_command_line, boot_command_line);
 443         strcpy (static_command_line, command_line);
 444 }
 445
 446 /*
 447  * We need to finalize in a non-__init function or else race conditions
 448  * between the root thread and the init thread may cause start_kernel to
 449  * be reaped by free_initmem before the root thread has proceeded to
 450  * cpu_idle.
 451  *
 452  * gcc-3.4 accidentally inlines this function, so use noinline.
 453  */
 454
 455 static void noinline __init_refok rest_init(void)
 456         __releases(kernel_lock)
 457 {
 458         int pid;
 459
 460         kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
 461         numa_default_policy();
 462         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
 463         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
 464         unlock_kernel();
 465
 466         /*
 467          * The boot idle thread must execute schedule()
 468          * at least once to get things moving:
 469          */
 470         init_idle_bootup_task(current);
 471         preempt_enable_no_resched();
 472         schedule();
 473         preempt_disable();
 474
 475         /* Call into cpu_idle with preempt disabled */
 476         cpu_idle();
 477 }
 478
 479 /* Check for early params. */
 480 static int __init do_early_param(char *param, char *val)
 481 {
 482         struct obs_kernel_param *p;
 483
 484         for (p = __setup_start; p < __setup_end; p++) {
 485                 if ((p->early && strcmp(param, p->str) == 0) ||
 486                     (strcmp(param, "console") == 0 &&
 487                      strcmp(p->str, "earlycon") == 0)
 488                 ) {
 489                         if (p->setup_func(val) != 0)
 490                                 printk(KERN_WARNING
 491                                        "Malformed early option '%s'\n", param);
 492                 }
 493         }
 494         /* We accept everything at this stage. */
 495         return 0;
 496 }
 497
 498 /* Arch code calls this early on, or if not, just before other parsing. */
 499 void __init parse_early_param(void)
 500 {
 501         static __initdata int done = 0;
 502         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 503
 504         if (done)
 505                 return;
 506
 507         /* All fall through to do_early_param. */
 508         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 509         parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 510         done = 1;
 511 }
 512
 513 /*
 514  *      Activate the first processor.
 515  */
 516
 517 static void __init boot_cpu_init(void)
 518 {
 519         int cpu = smp_processor_id();
 520         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
 521         cpu_set(cpu, cpu_online_map);
 522         cpu_set(cpu, cpu_present_map);
 523         cpu_set(cpu, cpu_possible_map);
 524 }
 525
 526 void __init __weak smp_setup_processor_id(void)
 527 {
 528 }
 529
 530 void __init __weak thread_info_cache_init(void)
 531 {
 532 }
 533
 534 asmlinkage void __init start_kernel(void)
 535 {
 536         char * command_line;
 537         extern struct kernel_param __start___param[], __stop___param[];
 538
 539         smp_setup_processor_id();
 540
 541         /*
 542          * Need to run as early as possible, to initialize the
 543          * lockdep hash:
 544          */
 545         unwind_init();
 546         lockdep_init();
 547         debug_objects_early_init();
 548         cgroup_init_early();
 549
 550         local_irq_disable();
 551         early_boot_irqs_off();
 552         early_init_irq_lock_class();
 553
 554 /*
 555  * Interrupts are still disabled. Do necessary setups, then
 556  * enable them
 557  */
 558         lock_kernel();
 559         tick_init();
 560         boot_cpu_init();
 561         page_address_init();
 562         printk(KERN_NOTICE);
 563         printk(linux_banner);
 564         setup_arch(&command_line);
 565         mm_init_owner(&init_mm, &init_task);
 566         setup_command_line(command_line);
 567         unwind_setup();
 568         setup_per_cpu_areas();
 569         setup_nr_cpu_ids();
 570         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
 571
 572         /*
 573          * Set up the scheduler prior starting any interrupts (such as the
 574          * timer interrupt). Full topology setup happens at smp_init()
 575          * time - but meanwhile we still have a functioning scheduler.
 576          */
 577         sched_init();
 578         /*
 579          * Disable preemption - early bootup scheduling is extremely
 580          * fragile until we cpu_idle() for the first time.
 581          */
 582         preempt_disable();
 583         build_all_zonelists();
 584         page_alloc_init();
 585         printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
 586         parse_early_param();
 587         parse_args("Booting kernel", static_command_line, __start___param,
 588                    __stop___param - __start___param,
 589                    &unknown_bootoption);
 590         if (!irqs_disabled()) {
 591                 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
 592                                 "enabled *very* early, fixing it\n");
 593                 local_irq_disable();
 594         }
 595         sort_main_extable();
 596         trap_init();
 597         rcu_init();
 598         /* init some links before init_ISA_irqs() */
 599         early_irq_init();
 600         init_IRQ();
 601         pidhash_init();
 602         init_timers();
 603         hrtimers_init();
 604         softirq_init();
 605         timekeeping_init();
 606         time_init();
 607         sched_clock_init();
 608         profile_init();
 609         if (!irqs_disabled())
 610                 printk("start_kernel(): bug: interrupts were enabled early\n");
 611         early_boot_irqs_on();
 612         local_irq_enable();
 613
 614         /*
 615          * HACK ALERT! This is early. We're enabling the console before
 616          * we've done PCI setups etc, and console_init() must be aware of
 617          * this. But we do want output early, in case something goes wrong.
 618          */
 619         console_init();
 620         if (panic_later)
 621                 panic(panic_later, panic_param);
 622
 623         lockdep_info();
 624
 625         /*
 626          * Need to run this when irqs are enabled, because it wants
 627          * to self-test [hard/soft]-irqs on/off lock inversion bugs
 628          * too:
 629          */
 630         locking_selftest();
 631
 632 #ifdef CONFIG_BLK_DEV_INITRD
 633         if (initrd_start && !initrd_below_start_ok &&
 634             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
 635                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 636                     "disabling it.\n",
 637                     page_to_pfn(virt_to_page((void *)initrd_start)),
 638                     min_low_pfn);
 639                 initrd_start = 0;
 640         }
 641 #endif
 642         vmalloc_init();
 643         vfs_caches_init_early();
 644         cpuset_init_early();
 645         page_cgroup_init();
 646         mem_init();
 647         enable_debug_pagealloc();
 648         cpu_hotplug_init();
 649         kmem_cache_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         calibrate_delay();
 657         pidmap_init();
 658         pgtable_cache_init();
 659         prio_tree_init();
 660         anon_vma_init();
 661 #ifdef CONFIG_X86
 662         if (efi_enabled)
 663                 efi_enter_virtual_mode();
 664 #endif
 665         thread_info_cache_init();
 666         cred_init();
 667         fork_init(num_physpages);
 668         proc_caches_init();
 669         buffer_init();
 670         key_init();
 671         security_init();
 672         vfs_caches_init(num_physpages);
 673         radix_tree_init();
 674         signals_init();
 675         /* rootfs populating might need page-writeback */
 676         page_writeback_init();
 677 #ifdef CONFIG_PROC_FS
 678         proc_root_init();
 679 #endif
 680         cgroup_init();
 681         cpuset_init();
 682         taskstats_init_early();
 683         delayacct_init();
 684
 685         check_bugs();
 686
 687         acpi_early_init(); /* before LAPIC and SMP init */
 688
 689         ftrace_init();
 690
 691         /* Do the rest non-__init'ed, we're now alive */
 692         rest_init();
 693 }
 694
 695 static int initcall_debug;
 696 core_param(initcall_debug, initcall_debug, bool, 0644);
 697
 698 int do_one_initcall(initcall_t fn)
 699 {
 700         int count = preempt_count();
 701         ktime_t calltime, delta, rettime;
 702         char msgbuf[64];
 703         struct boot_trace_call call;
 704         struct boot_trace_ret ret;
 705
 706         if (initcall_debug) {
 707                 call.caller = task_pid_nr(current);
 708                 printk("calling  %pF @ %i\n", fn, call.caller);
 709                 calltime = ktime_get();
 710                 trace_boot_call(&call, fn);
 711                 enable_boot_trace();
 712         }
 713
 714         ret.result = fn();
 715
 716         if (initcall_debug) {
 717                 disable_boot_trace();
 718                 rettime = ktime_get();
 719                 delta = ktime_sub(rettime, calltime);
 720                 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
 721                 trace_boot_ret(&ret, fn);
 722                 printk("initcall %pF returned %d after %Ld usecs\n", fn,
 723                         ret.result, ret.duration);
 724         }
 725
 726         msgbuf[0] = 0;
 727
 728         if (ret.result && ret.result != -ENODEV && initcall_debug)
 729                 sprintf(msgbuf, "error code %d ", ret.result);
 730
 731         if (preempt_count() != count) {
 732                 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
 733                 preempt_count() = count;
 734         }
 735         if (irqs_disabled()) {
 736                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
 737                 local_irq_enable();
 738         }
 739         if (msgbuf[0]) {
 740                 printk("initcall %pF returned with %s\n", fn, msgbuf);
 741         }
 742
 743         return ret.result;
 744 }
 745
 746
 747 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
 748
 749 static void __init do_initcalls(void)
 750 {
 751         initcall_t *call;
 752
 753         for (call = __early_initcall_end; call < __initcall_end; call++)
 754                 do_one_initcall(*call);
 755
 756         /* Make sure there is no pending stuff from the initcall sequence */
 757         flush_scheduled_work();
 758 }
 759
 760 /*
 761  * Ok, the machine is now initialized. None of the devices
 762  * have been touched yet, but the CPU subsystem is up and
 763  * running, and memory and process management works.
 764  *
 765  * Now we can finally start doing some real work..
 766  */
 767 static void __init do_basic_setup(void)
 768 {
 769         rcu_init_sched(); /* needed by module_init stage. */
 770         init_workqueues();
 771         usermodehelper_init();
 772         driver_init();
 773         init_irq_proc();
 774         do_initcalls();
 775 }
 776
 777 static void __init do_pre_smp_initcalls(void)
 778 {
 779         initcall_t *call;
 780
 781         for (call = __initcall_start; call < __early_initcall_end; call++)
 782                 do_one_initcall(*call);
 783 }
 784
 785 static void run_init_process(char *init_filename)
 786 {
 787         argv_init[0] = init_filename;
 788         kernel_execve(init_filename, argv_init, envp_init);
 789 }
 790
 791 /* This is a non __init function. Force it to be noinline otherwise gcc
 792  * makes it inline to init() and it becomes part of init.text section
 793  */
 794 static int noinline init_post(void)
 795 {
 796         free_initmem();
 797         unlock_kernel();
 798         mark_rodata_ro();
 799         system_state = SYSTEM_RUNNING;
 800         numa_default_policy();
 801
 802         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 803                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 804
 805         (void) sys_dup(0);
 806         (void) sys_dup(0);
 807
 808         current->signal->flags |= SIGNAL_UNKILLABLE;
 809
 810         if (ramdisk_execute_command) {
 811                 run_init_process(ramdisk_execute_command);
 812                 printk(KERN_WARNING "Failed to execute %s\n",
 813                                 ramdisk_execute_command);
 814         }
 815
 816         /*
 817          * We try each of these until one succeeds.
 818          *
 819          * The Bourne shell can be used instead of init if we are
 820          * trying to recover a really broken machine.
 821          */
 822         if (execute_command) {
 823                 run_init_process(execute_command);
 824                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 825                                         "defaults...\n", execute_command);
 826         }
 827         run_init_process("/sbin/init");
 828         run_init_process("/etc/init");
 829         run_init_process("/bin/init");
 830         run_init_process("/bin/sh");
 831
 832         panic("No init found.  Try passing init= option to kernel.");
 833 }
 834
 835 static int __init kernel_init(void * unused)
 836 {
 837         lock_kernel();
 838         /*
 839          * init can run on any cpu.
 840          */
 841         set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
 842         /*
 843          * Tell the world that we're going to be the grim
 844          * reaper of innocent orphaned children.
 845          *
 846          * We don't want people to have to make incorrect
 847          * assumptions about where in the task array this
 848          * can be found.
 849          */
 850         init_pid_ns.child_reaper = current;
 851
 852         cad_pid = task_pid(current);
 853
 854         smp_prepare_cpus(setup_max_cpus);
 855
 856         do_pre_smp_initcalls();
 857         start_boot_trace();
 858
 859         smp_init();
 860         sched_init_smp();
 861
 862         cpuset_init_smp();
 863
 864         do_basic_setup();
 865
 866         /*
 867          * check if there is an early userspace init.  If yes, let it do all
 868          * the work
 869          */
 870
 871         if (!ramdisk_execute_command)
 872                 ramdisk_execute_command = "/init";
 873
 874         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 875                 ramdisk_execute_command = NULL;
 876                 prepare_namespace();
 877         }
 878
 879         /*
 880          * Ok, we have completed the initial bootup, and
 881          * we're essentially up and running. Get rid of the
 882          * initmem segments and start the user-mode stuff..
 883          */
 884
 885         init_post();
 886         return 0;
 887 }