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