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_NUBUS
  55 #include <linux/nubus.h>
  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__ < 91)
  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 static int init(void *);
  84
  85 extern void init_IRQ(void);
  86 extern void init_modules(void);
  87 extern void sock_init(void);
  88 extern void fork_init(unsigned long);
  89 extern void mca_init(void);
  90 extern void sbus_init(void);
  91 extern void ppc_init(void);
  92 extern void sysctl_init(void);
  93 extern void signals_init(void);
  94 extern void bdev_init(void);
  95 extern int init_pcmcia_ds(void);
  96 extern void net_notifier_init(void);
  97
  98 extern void free_initmem(void);
  99 extern void filesystem_setup(void);
 100
 101 #ifdef CONFIG_TC
 102 extern void tc_init(void);
 103 #endif
 104
 105 extern void ecard_init(void);
 106
 107 #if defined(CONFIG_SYSVIPC)
 108 extern void ipc_init(void);
 109 #endif
 110 #if defined(CONFIG_QUOTA)
 111 extern void dquot_init_hash(void);
 112 #endif
 113
 114 /*
 115  * Boot command-line arguments
 116  */
 117 #define MAX_INIT_ARGS 8
 118 #define MAX_INIT_ENVS 8
 119
 120 extern void time_init(void);
 121 extern void softirq_init(void);
 122
 123 int rows, cols;
 124
 125 #ifdef CONFIG_BLK_DEV_INITRD
 126 kdev_t real_root_dev;
 127 #endif
 128
 129 int root_mountflags = MS_RDONLY;
 130 char *execute_command;
 131 char root_device_name[64];
 132
 133
 134 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 135 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 136
 137 static int __init profile_setup(char *str)
 138 {
 139     int par;
 140     if (get_option(&str,&par)) prof_shift = par;
 141         return 1;
 142 }
 143
 144 __setup("profile=", profile_setup);
 145
 146
 147 static struct dev_name_struct {
 148         const char *name;
 149         const int num;
 150 } root_dev_names[] __initdata = {
 151         { "nfs",     0x00ff },
 152         { "hda",     0x0300 },
 153         { "hdb",     0x0340 },
 154         { "hdc",     0x1600 },
 155         { "hdd",     0x1640 },
 156         { "hde",     0x2100 },
 157         { "hdf",     0x2140 },
 158         { "hdg",     0x2200 },
 159         { "hdh",     0x2240 },
 160         { "hdi",     0x3800 },
 161         { "hdj",     0x3840 },
 162         { "hdk",     0x3900 },
 163         { "hdl",     0x3940 },
 164         { "hdm",     0x5800 },
 165         { "hdn",     0x5840 },
 166         { "hdo",     0x5900 },
 167         { "hdp",     0x5940 },
 168         { "hdq",     0x5A00 },
 169         { "hdr",     0x5A40 },
 170         { "hds",     0x5B00 },
 171         { "hdt",     0x5B40 },
 172         { "sda",     0x0800 },
 173         { "sdb",     0x0810 },
 174         { "sdc",     0x0820 },
 175         { "sdd",     0x0830 },
 176         { "sde",     0x0840 },
 177         { "sdf",     0x0850 },
 178         { "sdg",     0x0860 },
 179         { "sdh",     0x0870 },
 180         { "sdi",     0x0880 },
 181         { "sdj",     0x0890 },
 182         { "sdk",     0x08a0 },
 183         { "sdl",     0x08b0 },
 184         { "sdm",     0x08c0 },
 185         { "sdn",     0x08d0 },
 186         { "sdo",     0x08e0 },
 187         { "sdp",     0x08f0 },
 188         { "ada",     0x1c00 },
 189         { "adb",     0x1c10 },
 190         { "adc",     0x1c20 },
 191         { "add",     0x1c30 },
 192         { "ade",     0x1c40 },
 193         { "fd",      0x0200 },
 194         { "md",      0x0900 },
 195         { "xda",     0x0d00 },
 196         { "xdb",     0x0d40 },
 197         { "ram",     0x0100 },
 198         { "scd",     0x0b00 },
 199         { "mcd",     0x1700 },
 200         { "cdu535",  0x1800 },
 201         { "sonycd",  0x1800 },
 202         { "aztcd",   0x1d00 },
 203         { "cm206cd", 0x2000 },
 204         { "gscd",    0x1000 },
 205         { "sbpcd",   0x1900 },
 206         { "eda",     0x2400 },
 207         { "edb",     0x2440 },
 208         { "pda",        0x2d00 },
 209         { "pdb",        0x2d10 },
 210         { "pdc",        0x2d20 },
 211         { "pdd",        0x2d30 },
 212         { "pcd",        0x2e00 },
 213         { "pf",         0x2f00 },
 214         { "apblock", APBLOCK_MAJOR << 8},
 215         { "ddv", DDV_MAJOR << 8},
 216         { "jsfd",    JSFD_MAJOR << 8},
 217 #ifdef CONFIG_MDISK
 218         { "mnda", (MDISK_MAJOR << MINORBITS)},
 219         { "mndb", (MDISK_MAJOR << MINORBITS) + 1},
 220         { "mndc", (MDISK_MAJOR << MINORBITS) + 2},
 221         { "mndd", (MDISK_MAJOR << MINORBITS) + 3},
 222         { "mnde", (MDISK_MAJOR << MINORBITS) + 4},
 223         { "mndf", (MDISK_MAJOR << MINORBITS) + 5},
 224         { "mndg", (MDISK_MAJOR << MINORBITS) + 6},
 225         { "mndh", (MDISK_MAJOR << MINORBITS) + 7},
 226 #endif
 227 #ifdef CONFIG_DASD
 228         { "dasda", (DASD_MAJOR << MINORBITS) },
 229         { "dasdb", (DASD_MAJOR << MINORBITS) + (1 << 2) },
 230         { "dasdc", (DASD_MAJOR << MINORBITS) + (2 << 2) },
 231         { "dasdd", (DASD_MAJOR << MINORBITS) + (3 << 2) },
 232         { "dasde", (DASD_MAJOR << MINORBITS) + (4 << 2) },
 233         { "dasdf", (DASD_MAJOR << MINORBITS) + (5 << 2) },
 234         { "dasdg", (DASD_MAJOR << MINORBITS) + (6 << 2) },
 235         { "dasdh", (DASD_MAJOR << MINORBITS) + (7 << 2) },
 236 #endif
 237 #if defined(CONFIG_BLK_CPQ_DA) || defined(CONFIG_BLK_CPQ_DA_MODULE)
 238         { "ida/c0d0p",0x4800 },
 239         { "ida/c0d1p",0x4810 },
 240         { "ida/c0d2p",0x4820 },
 241         { "ida/c0d3p",0x4830 },
 242         { "ida/c0d4p",0x4840 },
 243         { "ida/c0d5p",0x4850 },
 244         { "ida/c0d6p",0x4860 },
 245         { "ida/c0d7p",0x4870 },
 246         { "ida/c0d8p",0x4880 },
 247         { "ida/c0d9p",0x4890 },
 248         { "ida/c0d10p",0x48A0 },
 249         { "ida/c0d11p",0x48B0 },
 250         { "ida/c0d12p",0x48C0 },
 251         { "ida/c0d13p",0x48D0 },
 252         { "ida/c0d14p",0x48E0 },
 253         { "ida/c0d15p",0x48F0 },
 254 #endif
 255 #if defined(CONFIG_BLK_CPQ_CISS_DA) || defined(CONFIG_BLK_CPQ_CISS_DA_MODULE)
 256         { "cciss/c0d0p",0x6800 },
 257         { "cciss/c0d1p",0x6810 },
 258         { "cciss/c0d2p",0x6820 },
 259         { "cciss/c0d3p",0x6830 },
 260         { "cciss/c0d4p",0x6840 },
 261         { "cciss/c0d5p",0x6850 },
 262         { "cciss/c0d6p",0x6860 },
 263         { "cciss/c0d7p",0x6870 },
 264         { "cciss/c0d8p",0x6880 },
 265         { "cciss/c0d9p",0x6890 },
 266         { "cciss/c0d10p",0x68A0 },
 267         { "cciss/c0d11p",0x68B0 },
 268         { "cciss/c0d12p",0x68C0 },
 269         { "cciss/c0d13p",0x68D0 },
 270         { "cciss/c0d14p",0x68E0 },
 271         { "cciss/c0d15p",0x68F0 },
 272 #endif
 273 #ifdef CONFIG_NFTL
 274         { "nftla", 0x5d00 },
 275 #endif
 276         { NULL, 0 }
 277 };
 278
 279 kdev_t __init name_to_kdev_t(char *line)
 280 {
 281         int base = 0;
 282
 283         if (strncmp(line,"/dev/",5) == 0) {
 284                 struct dev_name_struct *dev = root_dev_names;
 285                 line += 5;
 286                 do {
 287                         int len = strlen(dev->name);
 288                         if (strncmp(line,dev->name,len) == 0) {
 289                                 line += len;
 290                                 base = dev->num;
 291                                 break;
 292                         }
 293                         dev++;
 294                 } while (dev->name);
 295         }
 296         return to_kdev_t(base + simple_strtoul(line,NULL,base?10:16));
 297 }
 298
 299 static int __init root_dev_setup(char *line)
 300 {
 301         int i;
 302         char ch;
 303
 304         ROOT_DEV = name_to_kdev_t(line);
 305         memset (root_device_name, 0, sizeof root_device_name);
 306         if (strncmp (line, "/dev/", 5) == 0) line += 5;
 307         for (i = 0; i < sizeof root_device_name - 1; ++i)
 308         {
 309             ch = line[i];
 310             if ( isspace (ch) || (ch == ',') || (ch == '\0') ) break;
 311             root_device_name[i] = ch;
 312         }
 313         return 1;
 314 }
 315
 316 __setup("root=", root_dev_setup);
 317
 318 static int __init checksetup(char *line)
 319 {
 320         struct kernel_param *p;
 321
 322         p = &__setup_start;
 323         do {
 324                 int n = strlen(p->str);
 325                 if (!strncmp(line,p->str,n)) {
 326                         if (p->setup_func(line+n))
 327                                 return 1;
 328                 }
 329                 p++;
 330         } while (p < &__setup_end);
 331         return 0;
 332 }
 333
 334 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
 335    still work even if initially too large, it will just take slightly longer */
 336 unsigned long loops_per_jiffy = (1<<12);
 337
 338 /* This is the number of bits of precision for the loops_per_jiffy.  Each
 339    bit takes on average 1.5/HZ seconds.  This (like the original) is a little
 340    better than 1% */
 341 #define LPS_PREC 8
 342
 343 void __init calibrate_delay(void)
 344 {
 345         unsigned long ticks, loopbit;
 346         int lps_precision = LPS_PREC;
 347
 348         loops_per_jiffy = (1<<12);
 349
 350         printk("Calibrating delay loop... ");
 351         while (loops_per_jiffy <<= 1) {
 352                 /* wait for "start of" clock tick */
 353                 ticks = jiffies;
 354                 while (ticks == jiffies)
 355                         /* nothing */;
 356                 /* Go .. */
 357                 ticks = jiffies;
 358                 __delay(loops_per_jiffy);
 359                 ticks = jiffies - ticks;
 360                 if (ticks)
 361                         break;
 362         }
 363
 364 /* Do a binary approximation to get loops_per_jiffy set to equal one clock
 365    (up to lps_precision bits) */
 366         loops_per_jiffy >>= 1;
 367         loopbit = loops_per_jiffy;
 368         while ( lps_precision-- && (loopbit >>= 1) ) {
 369                 loops_per_jiffy |= loopbit;
 370                 ticks = jiffies;
 371                 while (ticks == jiffies);
 372                 ticks = jiffies;
 373                 __delay(loops_per_jiffy);
 374                 if (jiffies != ticks)   /* longer than 1 tick */
 375                         loops_per_jiffy &= ~loopbit;
 376         }
 377
 378 /* Round the value and print it */
 379         printk("%lu.%02lu BogoMIPS\n",
 380                 loops_per_jiffy/(500000/HZ),
 381                 (loops_per_jiffy/(5000/HZ)) % 100);
 382 }
 383
 384 static int __init readonly(char *str)
 385 {
 386         if (*str)
 387                 return 0;
 388         root_mountflags |= MS_RDONLY;
 389         return 1;
 390 }
 391
 392 static int __init readwrite(char *str)
 393 {
 394         if (*str)
 395                 return 0;
 396         root_mountflags &= ~MS_RDONLY;
 397         return 1;
 398 }
 399
 400 static int __init debug_kernel(char *str)
 401 {
 402         if (*str)
 403                 return 0;
 404         console_loglevel = 10;
 405         return 1;
 406 }
 407
 408 static int __init quiet_kernel(char *str)
 409 {
 410         if (*str)
 411                 return 0;
 412         console_loglevel = 4;
 413         return 1;
 414 }
 415
 416 __setup("ro", readonly);
 417 __setup("rw", readwrite);
 418 __setup("debug", debug_kernel);
 419 __setup("quiet", quiet_kernel);
 420
 421 /*
 422  * This is a simple kernel command line parsing function: it parses
 423  * the command line, and fills in the arguments/environment to init
 424  * as appropriate. Any cmd-line option is taken to be an environment
 425  * variable if it contains the character '='.
 426  *
 427  * This routine also checks for options meant for the kernel.
 428  * These options are not given to init - they are for internal kernel use only.
 429  */
 430 static void __init parse_options(char *line)
 431 {
 432         char *next,*quote;
 433         int args, envs;
 434
 435         if (!*line)
 436                 return;
 437         args = 0;
 438         envs = 1;       /* TERM is set to 'linux' by default */
 439         next = line;
 440         while ((line = next) != NULL) {
 441                 quote = strchr(line,'"');
 442                 next = strchr(line, ' ');
 443                 while (next != NULL && quote != NULL && quote < next) {
 444                         /* we found a left quote before the next blank
 445                          * now we have to find the matching right quote
 446                          */
 447                         next = strchr(quote+1, '"');
 448                         if (next != NULL) {
 449                                 quote = strchr(next+1, '"');
 450                                 next = strchr(next+1, ' ');
 451                         }
 452                 }
 453                 if (next != NULL)
 454                         *next++ = 0;
 455                 if (!strncmp(line,"init=",5)) {
 456                         line += 5;
 457                         execute_command = line;
 458                         /* In case LILO is going to boot us with default command line,
 459                          * it prepends "auto" before the whole cmdline which makes
 460                          * the shell think it should execute a script with such name.
 461                          * So we ignore all arguments entered _before_ init=... [MJ]
 462                          */
 463                         args = 0;
 464                         continue;
 465                 }
 466                 if (checksetup(line))
 467                         continue;
 468
 469                 /*
 470                  * Then check if it's an environment variable or
 471                  * an option.
 472                  */
 473                 if (strchr(line,'=')) {
 474                         if (envs >= MAX_INIT_ENVS)
 475                                 break;
 476                         envp_init[++envs] = line;
 477                 } else {
 478                         if (args >= MAX_INIT_ARGS)
 479                                 break;
 480                         if (*line)
 481                                 argv_init[++args] = line;
 482                 }
 483         }
 484         argv_init[args+1] = NULL;
 485         envp_init[envs+1] = NULL;
 486 }
 487
 488
 489 extern void setup_arch(char **);
 490 extern void cpu_idle(void);
 491
 492 #ifndef CONFIG_SMP
 493
 494 #ifdef CONFIG_X86_IO_APIC
 495 static void __init smp_init(void)
 496 {
 497         IO_APIC_init_uniprocessor();
 498 }
 499 #else
 500 #define smp_init()      do { } while (0)
 501 #endif
 502
 503 #else
 504
 505 /* Called by boot processor to activate the rest. */
 506 static void __init smp_init(void)
 507 {
 508         /* Get other processors into their bootup holding patterns. */
 509         smp_boot_cpus();
 510         smp_threads_ready=1;
 511         smp_commence();
 512 }
 513
 514 #endif
 515
 516 /*
 517  *      Activate the first processor.
 518  */
 519
 520 asmlinkage void __init start_kernel(void)
 521 {
 522         char * command_line;
 523         unsigned long mempages;
 524         extern char saved_command_line[];
 525 /*
 526  * Interrupts are still disabled. Do necessary setups, then
 527  * enable them
 528  */
 529         lock_kernel();
 530         printk(linux_banner);
 531         setup_arch(&command_line);
 532         printk("Kernel command line: %s\n", saved_command_line);
 533         parse_options(command_line);
 534         trap_init();
 535         init_IRQ();
 536         sched_init();
 537         time_init();
 538         softirq_init();
 539
 540         /*
 541          * HACK ALERT! This is early. We're enabling the console before
 542          * we've done PCI setups etc, and console_init() must be aware of
 543          * this. But we do want output early, in case something goes wrong.
 544          */
 545         console_init();
 546 #ifdef CONFIG_MODULES
 547         init_modules();
 548 #endif
 549         if (prof_shift) {
 550                 unsigned int size;
 551                 /* only text is profiled */
 552                 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 553                 prof_len >>= prof_shift;
 554
 555                 size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1;
 556                 prof_buffer = (unsigned int *) alloc_bootmem(size);
 557         }
 558
 559         kmem_cache_init();
 560         sti();
 561         calibrate_delay();
 562 #ifdef CONFIG_BLK_DEV_INITRD
 563         if (initrd_start && !initrd_below_start_ok &&
 564                         initrd_start < min_low_pfn << PAGE_SHIFT) {
 565                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 566                     "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 567                 initrd_start = 0;
 568         }
 569 #endif
 570         mem_init();
 571         kmem_cache_sizes_init();
 572 #ifdef CONFIG_3215_CONSOLE
 573         con3215_activate();
 574 #endif
 575 #ifdef CONFIG_PROC_FS
 576         proc_root_init();
 577 #endif
 578         mempages = num_physpages;
 579
 580         fork_init(mempages);
 581         proc_caches_init();
 582         vfs_caches_init(mempages);
 583         buffer_init(mempages);
 584         page_cache_init(mempages);
 585         kiobuf_setup();
 586         signals_init();
 587         bdev_init();
 588         inode_init(mempages);
 589 #if defined(CONFIG_SYSVIPC)
 590         ipc_init();
 591 #endif
 592 #if defined(CONFIG_QUOTA)
 593         dquot_init_hash();
 594 #endif
 595         check_bugs();
 596         printk("POSIX conformance testing by UNIFIX\n");
 597
 598         /*
 599          *      We count on the initial thread going ok
 600          *      Like idlers init is an unlocked kernel thread, which will
 601          *      make syscalls (and thus be locked).
 602          */
 603         smp_init();
 604         kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL);
 605         unlock_kernel();
 606         current->need_resched = 1;
 607         cpu_idle();
 608 }
 609
 610 #ifdef CONFIG_BLK_DEV_INITRD
 611 static int do_linuxrc(void * shell)
 612 {
 613         static char *argv[] = { "linuxrc", NULL, };
 614
 615         close(0);close(1);close(2);
 616         setsid();
 617         (void) open("/dev/console",O_RDWR,0);
 618         (void) dup(0);
 619         (void) dup(0);
 620         return execve(shell, argv, envp_init);
 621 }
 622
 623 #endif
 624
 625 struct task_struct *child_reaper = &init_task;
 626
 627 static void __init do_initcalls(void)
 628 {
 629         initcall_t *call;
 630
 631         call = &__initcall_start;
 632         do {
 633                 (*call)();
 634                 call++;
 635         } while (call < &__initcall_end);
 636 }
 637
 638 /*
 639  * Ok, the machine is now initialized. None of the devices
 640  * have been touched yet, but the CPU subsystem is up and
 641  * running, and memory and process management works.
 642  *
 643  * Now we can finally start doing some real work..
 644  */
 645 static void __init do_basic_setup(void)
 646 {
 647 #ifdef CONFIG_BLK_DEV_INITRD
 648         int real_root_mountflags;
 649 #endif
 650
 651         /*
 652          * Tell the world that we're going to be the grim
 653          * reaper of innocent orphaned children.
 654          *
 655          * We don't want people to have to make incorrect
 656          * assumptions about where in the task array this
 657          * can be found.
 658          */
 659         child_reaper = current;
 660
 661 #if defined(CONFIG_MTRR)        /* Do this after SMP initialization */
 662 /*
 663  * We should probably create some architecture-dependent "fixup after
 664  * everything is up" style function where this would belong better
 665  * than in init/main.c..
 666  */
 667         mtrr_init();
 668 #endif
 669
 670 #ifdef CONFIG_SYSCTL
 671         sysctl_init();
 672 #endif
 673
 674         /*
 675          * Ok, at this point all CPU's should be initialized, so
 676          * we can start looking into devices..
 677          */
 678 #ifdef CONFIG_PCI
 679         pci_init();
 680 #endif
 681 #ifdef CONFIG_SBUS
 682         sbus_init();
 683 #endif
 684 #if defined(CONFIG_PPC)
 685         ppc_init();
 686 #endif
 687 #ifdef CONFIG_MCA
 688         mca_init();
 689 #endif
 690 #ifdef CONFIG_ARCH_ACORN
 691         ecard_init();
 692 #endif
 693 #ifdef CONFIG_ZORRO
 694         zorro_init();
 695 #endif
 696 #ifdef CONFIG_DIO
 697         dio_init();
 698 #endif
 699 #ifdef CONFIG_NUBUS
 700         nubus_init();
 701 #endif
 702 #ifdef CONFIG_ISAPNP
 703         isapnp_init();
 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         start_context_thread();
 720         do_initcalls();
 721
 722         /* .. filesystems .. */
 723         filesystem_setup();
 724
 725 #ifdef CONFIG_IRDA
 726         irda_device_init(); /* Must be done after protocol initialization */
 727 #endif
 728 #ifdef CONFIG_PCMCIA
 729         init_pcmcia_ds();               /* Do this last */
 730 #endif
 731
 732         /* Mount the root filesystem.. */
 733         mount_root();
 734
 735         mount_devfs_fs ();
 736
 737 #ifdef CONFIG_BLK_DEV_INITRD
 738         root_mountflags = real_root_mountflags;
 739         if (mount_initrd && ROOT_DEV != real_root_dev
 740             && MAJOR(ROOT_DEV) == RAMDISK_MAJOR && MINOR(ROOT_DEV) == 0) {
 741                 int error;
 742                 int i, pid;
 743
 744                 pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
 745                 if (pid>0)
 746                         while (pid != wait(&i));
 747                 if (MAJOR(real_root_dev) != RAMDISK_MAJOR
 748                      || MINOR(real_root_dev) != 0) {
 749                         error = change_root(real_root_dev,"/initrd");
 750                         if (error)
 751                                 printk(KERN_ERR "Change root to /initrd: "
 752                                     "error %d\n",error);
 753                 }
 754         }
 755 #endif
 756 }
 757
 758 static int init(void * unused)
 759 {
 760         lock_kernel();
 761         do_basic_setup();
 762
 763         /*
 764          * Ok, we have completed the initial bootup, and
 765          * we're essentially up and running. Get rid of the
 766          * initmem segments and start the user-mode stuff..
 767          */
 768         free_initmem();
 769         unlock_kernel();
 770
 771         if (open("/dev/console", O_RDWR, 0) < 0)
 772                 printk("Warning: unable to open an initial console.\n");
 773
 774         (void) dup(0);
 775         (void) dup(0);
 776
 777         /*
 778          * We try each of these until one succeeds.
 779          *
 780          * The Bourne shell can be used instead of init if we are
 781          * trying to recover a really broken machine.
 782          */
 783
 784         if (execute_command)
 785                 execve(execute_command,argv_init,envp_init);
 786         execve("/sbin/init",argv_init,envp_init);
 787         execve("/etc/init",argv_init,envp_init);
 788         execve("/bin/init",argv_init,envp_init);
 789         execve("/bin/sh",argv_init,envp_init);
 790         panic("No init found.  Try passing init= option to kernel.");
 791 }