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/config.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/devfs_fs_kernel.h>
  17 #include <linux/unistd.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/raid/md.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/blk.h>
  27 #include <linux/hdreg.h>
  28 #include <linux/iobuf.h>
  29 #include <linux/bootmem.h>
  30
  31 #include <asm/io.h>
  32 #include <asm/bugs.h>
  33
  34 #ifdef CONFIG_PCI
  35 #include <linux/pci.h>
  36 #endif
  37
  38 #ifdef CONFIG_DIO
  39 #include <linux/dio.h>
  40 #endif
  41
  42 #ifdef CONFIG_ZORRO
  43 #include <linux/zorro.h>
  44 #endif
  45
  46 #ifdef CONFIG_MTRR
  47 #  include <asm/mtrr.h>
  48 #endif
  49
  50 #ifdef CONFIG_3215_CONSOLE
  51 extern int con3215_activate(void);
  52 #endif
  53
  54 #ifdef CONFIG_MAC
  55 extern void nubus_init(void);
  56 #endif
  57
  58 #ifdef CONFIG_ISAPNP
  59 #include <linux/isapnp.h>
  60 #endif
  61
  62 #ifdef CONFIG_IRDA
  63 #include <net/irda/irda_device.h>
  64 #endif
  65
  66 #ifdef CONFIG_X86_IO_APIC
  67 #include <asm/smp.h>
  68 #endif
  69
  70 /*
  71  * Versions of gcc older than that listed below may actually compile
  72  * and link okay, but the end product can have subtle run time bugs.
  73  * To avoid associated bogus bug reports, we flatly refuse to compile
  74  * with a gcc that is known to be too old from the very beginning.
  75  */
  76 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
  77 #error sorry, your GCC is too old. It builds incorrect kernels.
  78 #endif
  79
  80 extern char _stext, _etext;
  81 extern char *linux_banner;
  82
  83 extern int console_loglevel;
  84
  85 static int init(void *);
  86
  87 extern void init_IRQ(void);
  88 extern void init_modules(void);
  89 extern void init_inventory(void);
  90 extern void sock_init(void);
  91 extern void fork_init(unsigned long);
  92 extern void mca_init(void);
  93 extern void sbus_init(void);
  94 extern void ppc_init(void);
  95 extern void sysctl_init(void);
  96 extern void filescache_init(void);
  97 extern void signals_init(void);
  98 extern void bdev_init(void);
  99 extern int init_pcmcia_ds(void);
 100 extern int usb_init(void);
 101
 102 extern void free_initmem(void);
 103 extern void filesystem_setup(void);
 104
 105 #ifdef CONFIG_TC
 106 extern void tc_init(void);
 107 #endif
 108
 109 extern void ecard_init(void);
 110
 111 #if defined(CONFIG_SYSVIPC)
 112 extern void ipc_init(void);
 113 #endif
 114 #if defined(CONFIG_QUOTA)
 115 extern void dquot_init_hash(void);
 116 #endif
 117
 118 #ifdef CONFIG_REMOTE_DEBUG
 119 #include <asm/gdb-stub.h>
 120 #endif
 121
 122 /*
 123  * Boot command-line arguments
 124  */
 125 #define MAX_INIT_ARGS 8
 126 #define MAX_INIT_ENVS 8
 127
 128 extern void time_init(void);
 129 extern void softirq_init(void);
 130
 131 int rows, cols;
 132
 133 #ifdef CONFIG_BLK_DEV_INITRD
 134 kdev_t real_root_dev;
 135 #endif
 136
 137 int root_mountflags = MS_RDONLY;
 138 char *execute_command;
 139 char root_device_name[64];
 140
 141
 142 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 143 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 144
 145 static int __init profile_setup(char *str)
 146 {
 147     int par;
 148     if (get_option(&str,&par)) prof_shift = par;
 149         return 1;
 150 }
 151
 152 __setup("profile=", profile_setup);
 153
 154
 155 static struct dev_name_struct {
 156         const char *name;
 157         const int num;
 158 } root_dev_names[] __initdata = {
 159         { "nfs",     0x00ff },
 160         { "hda",     0x0300 },
 161         { "hdb",     0x0340 },
 162         { "hdc",     0x1600 },
 163         { "hdd",     0x1640 },
 164         { "hde",     0x2100 },
 165         { "hdf",     0x2140 },
 166         { "hdg",     0x2200 },
 167         { "hdh",     0x2240 },
 168         { "hdi",     0x3800 },
 169         { "hdj",     0x3840 },
 170         { "hdk",     0x3900 },
 171         { "hdl",     0x3940 },
 172         { "hdm",     0x5800 },
 173         { "hdn",     0x5840 },
 174         { "hdo",     0x5900 },
 175         { "hdp",     0x5940 },
 176         { "hdq",     0x5A00 },
 177         { "hdr",     0x5A40 },
 178         { "hds",     0x5B00 },
 179         { "hdt",     0x5B40 },
 180         { "sda",     0x0800 },
 181         { "sdb",     0x0810 },
 182         { "sdc",     0x0820 },
 183         { "sdd",     0x0830 },
 184         { "sde",     0x0840 },
 185         { "sdf",     0x0850 },
 186         { "sdg",     0x0860 },
 187         { "sdh",     0x0870 },
 188         { "sdi",     0x0880 },
 189         { "sdj",     0x0890 },
 190         { "sdk",     0x08a0 },
 191         { "sdl",     0x08b0 },
 192         { "sdm",     0x08c0 },
 193         { "sdn",     0x08d0 },
 194         { "sdo",     0x08e0 },
 195         { "sdp",     0x08f0 },
 196         { "ada",     0x1c00 },
 197         { "adb",     0x1c10 },
 198         { "adc",     0x1c20 },
 199         { "add",     0x1c30 },
 200         { "ade",     0x1c40 },
 201         { "fd",      0x0200 },
 202         { "md",      0x0900 },
 203         { "xda",     0x0d00 },
 204         { "xdb",     0x0d40 },
 205         { "ram",     0x0100 },
 206         { "scd",     0x0b00 },
 207         { "mcd",     0x1700 },
 208         { "cdu535",  0x1800 },
 209         { "sonycd",  0x1800 },
 210         { "aztcd",   0x1d00 },
 211         { "cm206cd", 0x2000 },
 212         { "gscd",    0x1000 },
 213         { "sbpcd",   0x1900 },
 214         { "eda",     0x2400 },
 215         { "edb",     0x2440 },
 216         { "pda",        0x2d00 },
 217         { "pdb",        0x2d10 },
 218         { "pdc",        0x2d20 },
 219         { "pdd",        0x2d30 },
 220         { "pcd",        0x2e00 },
 221         { "pf",         0x2f00 },
 222         { "apblock", APBLOCK_MAJOR << 8},
 223         { "ddv", DDV_MAJOR << 8},
 224         { "jsfd",    JSFD_MAJOR << 8},
 225 #ifdef CONFIG_MDISK
 226         { "mnda", (MDISK_MAJOR << MINORBITS)},
 227         { "mndb", (MDISK_MAJOR << MINORBITS) + 1},
 228         { "mndc", (MDISK_MAJOR << MINORBITS) + 2},
 229         { "mndd", (MDISK_MAJOR << MINORBITS) + 3},
 230         { "mnde", (MDISK_MAJOR << MINORBITS) + 4},
 231         { "mndf", (MDISK_MAJOR << MINORBITS) + 5},
 232         { "mndg", (MDISK_MAJOR << MINORBITS) + 6},
 233         { "mndh", (MDISK_MAJOR << MINORBITS) + 7},
 234 #endif
 235 #ifdef CONFIG_DASD
 236         { "dasda", (DASD_MAJOR << MINORBITS) },
 237         { "dasdb", (DASD_MAJOR << MINORBITS) + (1 << 2) },
 238         { "dasdc", (DASD_MAJOR << MINORBITS) + (2 << 2) },
 239         { "dasdd", (DASD_MAJOR << MINORBITS) + (3 << 2) },
 240         { "dasde", (DASD_MAJOR << MINORBITS) + (4 << 2) },
 241         { "dasdf", (DASD_MAJOR << MINORBITS) + (5 << 2) },
 242         { "dasdg", (DASD_MAJOR << MINORBITS) + (6 << 2) },
 243         { "dasdh", (DASD_MAJOR << MINORBITS) + (7 << 2) },
 244 #endif
 245 #if defined(CONFIG_BLK_CPQ_DA) || defined(CONFIG_BLK_CPQ_DA_MODULE)
 246         { "ida/c0d0p",0x4800 },
 247         { "ida/c0d1p",0x4810 },
 248         { "ida/c0d2p",0x4820 },
 249         { "ida/c0d3p",0x4830 },
 250         { "ida/c0d4p",0x4840 },
 251         { "ida/c0d5p",0x4850 },
 252         { "ida/c0d6p",0x4860 },
 253         { "ida/c0d7p",0x4870 },
 254         { "ida/c0d8p",0x4880 },
 255         { "ida/c0d9p",0x4890 },
 256         { "ida/c0d10p",0x48A0 },
 257         { "ida/c0d11p",0x48B0 },
 258         { "ida/c0d12p",0x48C0 },
 259         { "ida/c0d13p",0x48D0 },
 260         { "ida/c0d14p",0x48E0 },
 261         { "ida/c0d15p",0x48F0 },
 262 #endif
 263
 264         { NULL, 0 }
 265 };
 266
 267 kdev_t __init name_to_kdev_t(char *line)
 268 {
 269         int base = 0;
 270
 271         if (strncmp(line,"/dev/",5) == 0) {
 272                 struct dev_name_struct *dev = root_dev_names;
 273                 line += 5;
 274                 do {
 275                         int len = strlen(dev->name);
 276                         if (strncmp(line,dev->name,len) == 0) {
 277                                 line += len;
 278                                 base = dev->num;
 279                                 break;
 280                         }
 281                         dev++;
 282                 } while (dev->name);
 283         }
 284         return to_kdev_t(base + simple_strtoul(line,NULL,base?10:16));
 285 }
 286
 287 static int __init root_dev_setup(char *line)
 288 {
 289         int i;
 290         char ch;
 291
 292         ROOT_DEV = name_to_kdev_t(line);
 293         memset (root_device_name, 0, sizeof root_device_name);
 294         if (strncmp (line, "/dev/", 5) == 0) line += 5;
 295         for (i = 0; i < sizeof root_device_name - 1; ++i)
 296         {
 297             ch = line[i];
 298             if ( isspace (ch) || (ch == ',') || (ch == '\0') ) break;
 299             root_device_name[i] = ch;
 300         }
 301         return 1;
 302 }
 303
 304 __setup("root=", root_dev_setup);
 305
 306 static int __init checksetup(char *line)
 307 {
 308         struct kernel_param *p;
 309
 310         p = &__setup_start;
 311         do {
 312                 int n = strlen(p->str);
 313                 if (!strncmp(line,p->str,n)) {
 314                         if (p->setup_func(line+n))
 315                                 return 1;
 316                 }
 317                 p++;
 318         } while (p < &__setup_end);
 319         return 0;
 320 }
 321
 322 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
 323    still work even if initially too large, it will just take slightly longer */
 324 unsigned long loops_per_sec = (1<<12);
 325
 326 /* This is the number of bits of precision for the loops_per_second.  Each
 327    bit takes on average 1.5/HZ seconds.  This (like the original) is a little
 328    better than 1% */
 329 #define LPS_PREC 8
 330
 331 void __init calibrate_delay(void)
 332 {
 333         unsigned long ticks, loopbit;
 334         int lps_precision = LPS_PREC;
 335
 336         loops_per_sec = (1<<12);
 337
 338         printk("Calibrating delay loop... ");
 339         while (loops_per_sec <<= 1) {
 340                 /* wait for "start of" clock tick */
 341                 ticks = jiffies;
 342                 while (ticks == jiffies)
 343                         /* nothing */;
 344                 /* Go .. */
 345                 ticks = jiffies;
 346                 __delay(loops_per_sec);
 347                 ticks = jiffies - ticks;
 348                 if (ticks)
 349                         break;
 350         }
 351
 352 /* Do a binary approximation to get loops_per_second set to equal one clock
 353    (up to lps_precision bits) */
 354         loops_per_sec >>= 1;
 355         loopbit = loops_per_sec;
 356         while ( lps_precision-- && (loopbit >>= 1) ) {
 357                 loops_per_sec |= loopbit;
 358                 ticks = jiffies;
 359                 while (ticks == jiffies);
 360                 ticks = jiffies;
 361                 __delay(loops_per_sec);
 362                 if (jiffies != ticks)   /* longer than 1 tick */
 363                         loops_per_sec &= ~loopbit;
 364         }
 365
 366 /* finally, adjust loops per second in terms of seconds instead of clocks */
 367         loops_per_sec *= HZ;
 368 /* Round the value and print it */
 369         printk("%lu.%02lu BogoMIPS\n",
 370                 (loops_per_sec+2500)/500000,
 371                 ((loops_per_sec+2500)/5000) % 100);
 372 }
 373
 374 static int __init readonly(char *str)
 375 {
 376         if (*str)
 377                 return 0;
 378         root_mountflags |= MS_RDONLY;
 379         return 1;
 380 }
 381
 382 static int __init readwrite(char *str)
 383 {
 384         if (*str)
 385                 return 0;
 386         root_mountflags &= ~MS_RDONLY;
 387         return 1;
 388 }
 389
 390 static int __init debug_kernel(char *str)
 391 {
 392         if (*str)
 393                 return 0;
 394         console_loglevel = 10;
 395         return 1;
 396 }
 397
 398 static int __init quiet_kernel(char *str)
 399 {
 400         if (*str)
 401                 return 0;
 402         console_loglevel = 4;
 403         return 1;
 404 }
 405
 406 __setup("ro", readonly);
 407 __setup("rw", readwrite);
 408 __setup("debug", debug_kernel);
 409 __setup("quiet", quiet_kernel);
 410
 411 /*
 412  * This is a simple kernel command line parsing function: it parses
 413  * the command line, and fills in the arguments/environment to init
 414  * as appropriate. Any cmd-line option is taken to be an environment
 415  * variable if it contains the character '='.
 416  *
 417  * This routine also checks for options meant for the kernel.
 418  * These options are not given to init - they are for internal kernel use only.
 419  */
 420 static void __init parse_options(char *line)
 421 {
 422         char *next,*quote;
 423         int args, envs;
 424
 425         if (!*line)
 426                 return;
 427         args = 0;
 428         envs = 1;       /* TERM is set to 'linux' by default */
 429         next = line;
 430         while ((line = next) != NULL) {
 431                 quote = strchr(line,'"');
 432                 next = strchr(line, ' ');
 433                 while (next != NULL && quote != NULL && quote < next) {
 434                         /* we found a left quote before the next blank
 435                          * now we have to find the matching right quote
 436                          */
 437                         next = strchr(quote+1, '"');
 438                         if (next != NULL) {
 439                                 quote = strchr(next+1, '"');
 440                                 next = strchr(next+1, ' ');
 441                         }
 442                 }
 443                 if (next != NULL)
 444                         *next++ = 0;
 445                 if (!strncmp(line,"init=",5)) {
 446                         line += 5;
 447                         execute_command = line;
 448                         /* In case LILO is going to boot us with default command line,
 449                          * it prepends "auto" before the whole cmdline which makes
 450                          * the shell think it should execute a script with such name.
 451                          * So we ignore all arguments entered _before_ init=... [MJ]
 452                          */
 453                         args = 0;
 454                         continue;
 455                 }
 456                 if (checksetup(line))
 457                         continue;
 458
 459                 /*
 460                  * Then check if it's an environment variable or
 461                  * an option.
 462                  */
 463                 if (strchr(line,'=')) {
 464                         if (envs >= MAX_INIT_ENVS)
 465                                 break;
 466                         envp_init[++envs] = line;
 467                 } else {
 468                         if (args >= MAX_INIT_ARGS)
 469                                 break;
 470                         if(*line)
 471                         argv_init[++args] = line;
 472                 }
 473         }
 474         argv_init[args+1] = NULL;
 475         envp_init[envs+1] = NULL;
 476 }
 477
 478
 479 extern void setup_arch(char **);
 480 extern void cpu_idle(void);
 481
 482 #ifndef CONFIG_SMP
 483
 484 #ifdef CONFIG_X86_IO_APIC
 485 static void __init smp_init(void)
 486 {
 487         IO_APIC_init_uniprocessor();
 488 }
 489 #else
 490 #define smp_init()      do { } while (0)
 491 #endif
 492
 493 #else
 494
 495 /* Called by boot processor to activate the rest. */
 496 static void __init smp_init(void)
 497 {
 498         /* Get other processors into their bootup holding patterns. */
 499         smp_boot_cpus();
 500         smp_threads_ready=1;
 501         smp_commence();
 502 }
 503
 504 #endif
 505
 506 /*
 507  *      Activate the first processor.
 508  */
 509
 510 asmlinkage void __init start_kernel(void)
 511 {
 512         char * command_line;
 513         unsigned long mempages;
 514         extern char saved_command_line[];
 515 /*
 516  * Interrupts are still disabled. Do necessary setups, then
 517  * enable them
 518  */
 519         lock_kernel();
 520         printk(linux_banner);
 521         setup_arch(&command_line);
 522         printk("Kernel command line: %s\n", saved_command_line);
 523         parse_options(command_line);
 524         trap_init();
 525         init_IRQ();
 526         sched_init();
 527         time_init();
 528         softirq_init();
 529
 530         /*
 531          * HACK ALERT! This is early. We're enabling the console before
 532          * we've done PCI setups etc, and console_init() must be aware of
 533          * this. But we do want output early, in case something goes wrong.
 534          */
 535         console_init();
 536 #ifdef CONFIG_MODULES
 537         init_modules();
 538 #endif
 539         if (prof_shift) {
 540                 unsigned int size;
 541                 /* only text is profiled */
 542                 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 543                 prof_len >>= prof_shift;
 544
 545                 size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1;
 546                 prof_buffer = (unsigned int *) alloc_bootmem(size);
 547         }
 548
 549         kmem_cache_init();
 550         sti();
 551         calibrate_delay();
 552 #ifdef CONFIG_BLK_DEV_INITRD
 553         if (initrd_start && !initrd_below_start_ok &&
 554                         initrd_start < min_low_pfn << PAGE_SHIFT) {
 555                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 556                     "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 557                 initrd_start = 0;
 558         }
 559 #endif
 560 #ifdef CONFIG_BINFMT_IRIX
 561         init_inventory();
 562 #endif
 563         mem_init();
 564         kmem_cache_sizes_init();
 565 #ifdef CONFIG_3215_CONSOLE
 566         con3215_activate();
 567 #endif
 568 #ifdef CONFIG_PROC_FS
 569         proc_root_init();
 570 #endif
 571         mempages = num_physpages;
 572
 573         fork_init(mempages);
 574         filescache_init();
 575         dcache_init(mempages);
 576         vma_init();
 577         buffer_init(mempages);
 578         page_cache_init(mempages);
 579         kiobuf_setup();
 580         signals_init();
 581         bdev_init();
 582         inode_init(mempages);
 583         file_table_init();
 584 #if defined(CONFIG_SYSVIPC)
 585         ipc_init();
 586 #endif
 587 #if defined(CONFIG_QUOTA)
 588         dquot_init_hash();
 589 #endif
 590         check_bugs();
 591         printk("POSIX conformance testing by UNIFIX\n");
 592
 593         /*
 594          *      We count on the initial thread going ok
 595          *      Like idlers init is an unlocked kernel thread, which will
 596          *      make syscalls (and thus be locked).
 597          */
 598         smp_init();
 599         kmem_cpucache_init();
 600         kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
 601         unlock_kernel();
 602         current->need_resched = 1;
 603         cpu_idle();
 604 }
 605
 606 #ifdef CONFIG_BLK_DEV_INITRD
 607 static int do_linuxrc(void * shell)
 608 {
 609         static char *argv[] = { "linuxrc", NULL, };
 610
 611         close(0);close(1);close(2);
 612         setsid();
 613         (void) open("/dev/console",O_RDWR,0);
 614         (void) dup(0);
 615         (void) dup(0);
 616         return execve(shell, argv, envp_init);
 617 }
 618
 619 #endif
 620
 621 struct task_struct *child_reaper = &init_task;
 622
 623 static void __init do_initcalls(void)
 624 {
 625         initcall_t *call;
 626
 627         call = &__initcall_start;
 628         do {
 629                 (*call)();
 630                 call++;
 631         } while (call < &__initcall_end);
 632 }
 633
 634 /*
 635  * Ok, the machine is now initialized. None of the devices
 636  * have been touched yet, but the CPU subsystem is up and
 637  * running, and memory and process management works.
 638  *
 639  * Now we can finally start doing some real work..
 640  */
 641 static void __init do_basic_setup(void)
 642 {
 643 #ifdef CONFIG_BLK_DEV_INITRD
 644         int real_root_mountflags;
 645 #endif
 646
 647         /*
 648          * Tell the world that we're going to be the grim
 649          * reaper of innocent orphaned children.
 650          *
 651          * We don't want people to have to make incorrect
 652          * assumptions about where in the task array this
 653          * can be found.
 654          */
 655         child_reaper = current;
 656
 657 #if defined(CONFIG_MTRR)        /* Do this after SMP initialization */
 658 /*
 659  * We should probably create some architecture-dependent "fixup after
 660  * everything is up" style function where this would belong better
 661  * than in init/main.c..
 662  */
 663         mtrr_init();
 664 #endif
 665
 666 #ifdef CONFIG_SYSCTL
 667         sysctl_init();
 668 #endif
 669
 670         /*
 671          * Ok, at this point all CPU's should be initialized, so
 672          * we can start looking into devices..
 673          */
 674 #ifdef CONFIG_PCI
 675         pci_init();
 676 #endif
 677 #ifdef CONFIG_SBUS
 678         sbus_init();
 679 #endif
 680 #if defined(CONFIG_PPC)
 681         ppc_init();
 682 #endif
 683 #ifdef CONFIG_MCA
 684         mca_init();
 685 #endif
 686 #ifdef CONFIG_ARCH_ACORN
 687         ecard_init();
 688 #endif
 689 #ifdef CONFIG_ZORRO
 690         zorro_init();
 691 #endif
 692 #ifdef CONFIG_DIO
 693         dio_init();
 694 #endif
 695 #ifdef CONFIG_MAC
 696         nubus_init();
 697 #endif
 698 #ifdef CONFIG_ISAPNP
 699         isapnp_init();
 700 #endif
 701 #ifdef CONFIG_USB
 702         usb_init();     /* Do this before doing initcalls, so that we can make
 703                         usbcore initialize here, and all drivers initialize later */
 704 #endif
 705 #ifdef CONFIG_TC
 706         tc_init();
 707 #endif
 708
 709         /* Networking initialization needs a process context */
 710         sock_init();
 711
 712 #ifdef CONFIG_BLK_DEV_INITRD
 713         real_root_dev = ROOT_DEV;
 714         real_root_mountflags = root_mountflags;
 715         if (initrd_start && mount_initrd) root_mountflags &= ~MS_RDONLY;
 716         else mount_initrd =0;
 717 #endif
 718
 719         do_initcalls();
 720
 721         /* .. filesystems .. */
 722         filesystem_setup();
 723
 724 #ifdef CONFIG_IRDA
 725         irda_device_init(); /* Must be done after protocol initialization */
 726 #endif
 727 #ifdef CONFIG_PCMCIA
 728         init_pcmcia_ds();               /* Do this last */
 729 #endif
 730         /* Mount the root filesystem.. */
 731         mount_root();
 732
 733         mount_devfs_fs ();
 734
 735 #ifdef CONFIG_BLK_DEV_INITRD
 736         root_mountflags = real_root_mountflags;
 737         if (mount_initrd && ROOT_DEV != real_root_dev
 738             && MAJOR(ROOT_DEV) == RAMDISK_MAJOR && MINOR(ROOT_DEV) == 0) {
 739                 int error;
 740                 int i, pid;
 741
 742                 pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
 743                 if (pid>0)
 744                         while (pid != wait(&i));
 745                 if (MAJOR(real_root_dev) != RAMDISK_MAJOR
 746                      || MINOR(real_root_dev) != 0) {
 747 #ifdef CONFIG_BLK_DEV_MD
 748                         md_run_setup();
 749 #endif
 750                         error = change_root(real_root_dev,"/initrd");
 751                         if (error)
 752                                 printk(KERN_ERR "Change root to /initrd: "
 753                                     "error %d\n",error);
 754                 }
 755         }
 756 #endif
 757 }
 758
 759 static int init(void * unused)
 760 {
 761         lock_kernel();
 762         do_basic_setup();
 763
 764         /*
 765          * Ok, we have completed the initial bootup, and
 766          * we're essentially up and running. Get rid of the
 767          * initmem segments and start the user-mode stuff..
 768          */
 769         free_initmem();
 770         unlock_kernel();
 771
 772         if (open("/dev/console", O_RDWR, 0) < 0)
 773                 printk("Warning: unable to open an initial console.\n");
 774
 775         (void) dup(0);
 776         (void) dup(0);
 777
 778         /*
 779          * We try each of these until one succeeds.
 780          *
 781          * The Bourne shell can be used instead of init if we are
 782          * trying to recover a really broken machine.
 783          */
 784
 785         if (execute_command)
 786                 execve(execute_command,argv_init,envp_init);
 787         execve("/sbin/init",argv_init,envp_init);
 788         execve("/etc/init",argv_init,envp_init);
 789         execve("/bin/init",argv_init,envp_init);
 790         execve("/bin/sh",argv_init,envp_init);
 791         panic("No init found.  Try passing init= option to kernel.");
 792 }