init/main.c

/* */
This source file includes following definitions.
get_options
profile_setup
ramdisk_start_setup
load_ramdisk
prompt_ramdisk
ramdisk_size
checksetup
calibrate_delay
parse_root_dev
parse_options
cpu_idle
start_secondary
smp_init
smp_begin
start_kernel
printf
do_rc
do_shell
do_linuxrc
no_initrd
init
   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  */
   9 
  10 #define __KERNEL_SYSCALLS__
  11 #include <stdarg.h>
  12 
  13 #include <asm/system.h>
  14 #include <asm/io.h>
  15 
  16 #include <linux/types.h>
  17 #include <linux/fcntl.h>
  18 #include <linux/config.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/tty.h>
  22 #include <linux/head.h>
  23 #include <linux/unistd.h>
  24 #include <linux/string.h>
  25 #include <linux/timer.h>
  26 #include <linux/fs.h>
  27 #include <linux/ctype.h>
  28 #include <linux/delay.h>
  29 #include <linux/utsname.h>
  30 #include <linux/ioport.h>
  31 #include <linux/hdreg.h>
  32 #include <linux/mm.h>
  33 #include <linux/major.h>
  34 #include <linux/blk.h>
  35 #ifdef CONFIG_ROOT_NFS
  36 #include <linux/nfs_fs.h>
  37 #endif
  38 
  39 #include <asm/bugs.h>
  40 
  41 extern char _stext, _etext;
  42 extern char *linux_banner;
  43 
  44 static char printbuf[1024];
  45 
  46 extern int console_loglevel;
  47 
  48 static int init(void *);
  49 extern int bdflush(void *);
  50 extern int kswapd(void *);
  51 
  52 extern void init_IRQ(void);
  53 extern void init_modules(void);
  54 extern long console_init(long, long);
  55 extern long kmalloc_init(long,long);
  56 extern void sock_init(void);
  57 extern long pci_init(long, long);
  58 extern void sysctl_init(void);
  59 
  60 extern void no_scroll(char *str, int *ints);
  61 extern void swap_setup(char *str, int *ints);
  62 extern void buff_setup(char *str, int *ints);
  63 extern void panic_setup(char *str, int *ints);
  64 extern void bmouse_setup(char *str, int *ints);
  65 extern void msmouse_setup(char *str, int *ints);
  66 extern void lp_setup(char *str, int *ints);
  67 extern void eth_setup(char *str, int *ints);
  68 extern void xd_setup(char *str, int *ints);
  69 extern void floppy_setup(char *str, int *ints);
  70 extern void st_setup(char *str, int *ints);
  71 extern void st0x_setup(char *str, int *ints);
  72 extern void advansys_setup(char *str, int *ints);
  73 extern void tmc8xx_setup(char *str, int *ints);
  74 extern void t128_setup(char *str, int *ints);
  75 extern void pas16_setup(char *str, int *ints);
  76 extern void generic_NCR5380_setup(char *str, int *intr);
  77 extern void generic_NCR53C400_setup(char *str, int *intr);
  78 extern void aha152x_setup(char *str, int *ints);
  79 extern void aha1542_setup(char *str, int *ints);
  80 extern void aic7xxx_setup(char *str, int *ints);
  81 extern void AM53C974_setup(char *str, int *ints);
  82 extern void BusLogic_Setup(char *str, int *ints);
  83 extern void fdomain_setup(char *str, int *ints);
  84 extern void in2000_setup(char *str, int *ints);
  85 extern void NCR53c406a_setup(char *str, int *ints);
  86 extern void ppa_setup(char *str, int *ints);
  87 extern void scsi_luns_setup(char *str, int *ints);
  88 extern void sound_setup(char *str, int *ints);
  89 #ifdef CONFIG_CDU31A
  90 extern void cdu31a_setup(char *str, int *ints);
  91 #endif CONFIG_CDU31A
  92 #ifdef CONFIG_MCD
  93 extern void mcd_setup(char *str, int *ints);
  94 #endif CONFIG_MCD
  95 #ifdef CONFIG_MCDX
  96 extern void mcdx_setup(char *str, int *ints);
  97 #endif CONFIG_MCDX
  98 #ifdef CONFIG_SBPCD
  99 extern void sbpcd_setup(char *str, int *ints);
 100 #endif CONFIG_SBPCD
 101 #ifdef CONFIG_AZTCD
 102 extern void aztcd_setup(char *str, int *ints);
 103 #endif CONFIG_AZTCD
 104 #ifdef CONFIG_CDU535
 105 extern void sonycd535_setup(char *str, int *ints);
 106 #endif CONFIG_CDU535
 107 #ifdef CONFIG_GSCD
 108 extern void gscd_setup(char *str, int *ints);
 109 #endif CONFIG_GSCD
 110 #ifdef CONFIG_CM206
 111 extern void cm206_setup(char *str, int *ints);
 112 #endif CONFIG_CM206
 113 #ifdef CONFIG_OPTCD
 114 extern void optcd_setup(char *str, int *ints);
 115 #endif CONFIG_OPTCD
 116 #ifdef CONFIG_SJCD
 117 extern void sjcd_setup(char *str, int *ints);
 118 #endif CONFIG_SJCD
 119 #ifdef CONFIG_ISP16_CDI
 120 extern void isp16_setup(char *str, int *ints);
 121 #endif CONFIG_ISP16_CDI
 122 #ifdef CONFIG_BLK_DEV_RAM
 123 static void ramdisk_start_setup(char *str, int *ints);
 124 static void load_ramdisk(char *str, int *ints);
 125 static void prompt_ramdisk(char *str, int *ints);
 126 static void ramdisk_size(char *str, int *ints);
 127 #ifdef CONFIG_BLK_DEV_INITRD
 128 static void no_initrd(char *s,int *ints);
 129 #endif
 130 #endif CONFIG_BLK_DEV_RAM
 131 #ifdef CONFIG_ISDN_DRV_ICN
 132 extern void icn_setup(char *str, int *ints);
 133 #endif
 134 #ifdef CONFIG_ISDN_DRV_TELES
 135 extern void teles_setup(char *str, int *ints);
 136 #endif
 137 
 138 #ifdef CONFIG_ATARIMOUSE
 139 extern void atari_mouse_setup (char *str, int *ints);
 140 #endif
 141 #ifdef CONFIG_DMASOUND
 142 extern void dmasound_setup (char *str, int *ints);
 143 #endif
 144 #ifdef CONFIG_ATARI_SCSI
 145 extern void atari_scsi_setup (char *str, int *ints);
 146 #endif
 147 extern void wd33c93_setup (char *str, int *ints);
 148 extern void gvp11_setup (char *str, int *ints);
 149 
 150 #ifdef CONFIG_DIGI
 151 extern void pcxx_setup(char *str, int *ints);
 152 #endif
 153 #ifdef CONFIG_ISDN_DRV_PCBIT
 154 extern void pcbit_setup(char *str, int *ints);
 155 #endif
 156 #ifdef CONFIG_RISCOM8
 157 extern void riscom8_setup(char *str, int *ints);
 158 #endif
 159 
 160 
 161 #if defined(CONFIG_SYSVIPC) || defined(CONFIG_KERNELD)
 162 extern void ipc_init(void);
 163 #endif
 164 
 165 /*
 166  * Boot command-line arguments
 167  */
 168 #define MAX_INIT_ARGS 8
 169 #define MAX_INIT_ENVS 8
 170 
 171 extern void time_init(void);
 172 
 173 static unsigned long memory_start = 0;
 174 static unsigned long memory_end = 0;
 175 
 176 int rows, cols;
 177 
 178 #ifdef CONFIG_BLK_DEV_RAM
 179 extern int rd_doload;           /* 1 = load ramdisk, 0 = don't load */
 180 extern int rd_prompt;           /* 1 = prompt for ramdisk, 0 = don't prompt */
 181 extern int rd_size;             /* Size of the ramdisk(s) */
 182 extern int rd_image_start;      /* starting block # of image */
 183 #ifdef CONFIG_BLK_DEV_INITRD
 184 kdev_t real_root_dev;
 185 #endif
 186 #endif
 187 
 188 int root_mountflags = MS_RDONLY;
 189 char *execute_command = 0;
 190 
 191 #ifdef CONFIG_ROOT_NFS
 192 char nfs_root_name[NFS_ROOT_NAME_LEN] = { "default" };
 193 char nfs_root_addrs[NFS_ROOT_ADDRS_LEN] = { "" };
 194 #endif
 195 
 196 extern void dquot_init(void);
 197 
 198 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 199 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 200 
 201 static char * argv_rc[] = { "/bin/sh", NULL };
 202 static char * envp_rc[] = { "HOME=/", "TERM=linux", NULL };
 203 
 204 static char * argv[] = { "-/bin/sh",NULL };
 205 static char * envp[] = { "HOME=/usr/root", "TERM=linux", NULL };
 206 
 207 char *get_options(char *str, int *ints)
     /*  */
 208 {
 209         char *cur = str;
 210         int i=1;
 211 
 212         while (cur && isdigit(*cur) && i <= 10) {
 213                 ints[i++] = simple_strtoul(cur,NULL,0);
 214                 if ((cur = strchr(cur,',')) != NULL)
 215                         cur++;
 216         }
 217         ints[0] = i-1;
 218         return(cur);
 219 }
 220 
 221 static void profile_setup(char *str, int *ints)
     /*  */
 222 {
 223         if (ints[0] > 0)
 224                 prof_shift = (unsigned long) ints[1];
 225         else
 226 #ifdef CONFIG_PROFILE_SHIFT
 227                 prof_shift = CONFIG_PROFILE_SHIFT;
 228 #else
 229                 prof_shift = 2;
 230 #endif
 231 }
 232 
 233 struct {
 234         const char *str;
 235         void (*setup_func)(char *, int *);
 236 } bootsetups[] = {
 237         { "reserve=", reserve_setup },
 238         { "profile=", profile_setup },
 239 #ifdef CONFIG_BLK_DEV_RAM
 240         { "ramdisk_start=", ramdisk_start_setup },
 241         { "load_ramdisk=", load_ramdisk },
 242         { "prompt_ramdisk=", prompt_ramdisk },
 243         { "ramdisk=", ramdisk_size },
 244         { "ramdisk_size=", ramdisk_size },
 245 #ifdef CONFIG_BLK_DEV_INITRD
 246         { "noinitrd", no_initrd },
 247 #endif
 248 #endif
 249         { "swap=", swap_setup },
 250         { "buff=", buff_setup },
 251         { "panic=", panic_setup },
 252         { "no-scroll", no_scroll },
 253 #ifdef CONFIG_BUGi386
 254         { "no-hlt", no_halt },
 255         { "no387", no_387 },
 256 #endif
 257 #ifdef CONFIG_INET
 258         { "ether=", eth_setup },
 259 #endif
 260 #ifdef CONFIG_PRINTER
 261         { "lp=", lp_setup },
 262 #endif
 263 #ifdef CONFIG_SCSI
 264         { "max_scsi_luns=", scsi_luns_setup },
 265 #endif
 266 #ifdef CONFIG_SCSI_ADVANSYS
 267         { "advansys=", advansys_setup },
 268 #endif
 269 #if defined(CONFIG_BLK_DEV_HD)
 270         { "hd=", hd_setup },
 271 #endif
 272 #ifdef CONFIG_CHR_DEV_ST
 273         { "st=", st_setup },
 274 #endif
 275 #ifdef CONFIG_BUSMOUSE
 276         { "bmouse=", bmouse_setup },
 277 #endif
 278 #ifdef CONFIG_MS_BUSMOUSE
 279         { "msmouse=", msmouse_setup },
 280 #endif
 281 #ifdef CONFIG_SCSI_SEAGATE
 282         { "st0x=", st0x_setup },
 283         { "tmc8xx=", tmc8xx_setup },
 284 #endif
 285 #ifdef CONFIG_SCSI_T128
 286         { "t128=", t128_setup },
 287 #endif
 288 #ifdef CONFIG_SCSI_PAS16
 289         { "pas16=", pas16_setup },
 290 #endif
 291 #ifdef CONFIG_SCSI_GENERIC_NCR5380
 292         { "ncr5380=", generic_NCR5380_setup },
 293         { "ncr53c400=", generic_NCR53C400_setup },
 294 #endif
 295 #ifdef CONFIG_SCSI_AHA152X
 296         { "aha152x=", aha152x_setup},
 297 #endif
 298 #ifdef CONFIG_SCSI_AHA1542
 299         { "aha1542=", aha1542_setup},
 300 #endif
 301 #ifdef CONFIG_SCSI_AIC7XXX
 302         { "aic7xxx=", aic7xxx_setup},
 303 #endif
 304 #ifdef CONFIG_SCSI_BUSLOGIC
 305         { "BusLogic=", BusLogic_Setup},
 306 #endif
 307 #ifdef CONFIG_SCSI_AM53C974
 308         { "AM53C974=", AM53C974_setup},
 309 #endif
 310 #ifdef CONFIG_SCSI_NCR53C406A
 311         { "ncr53c406a=", NCR53c406a_setup},
 312 #endif
 313 #ifdef CONFIG_SCSI_FUTURE_DOMAIN
 314         { "fdomain=", fdomain_setup},
 315 #endif
 316 #ifdef CONFIG_SCSI_IN2000
 317         { "in2000=", in2000_setup},
 318 #endif
 319 #ifdef CONFIG_SCSI_PPA
 320         { "ppa=", ppa_setup },
 321 #endif
 322 #ifdef CONFIG_BLK_DEV_XD
 323         { "xd=", xd_setup },
 324 #endif
 325 #ifdef CONFIG_BLK_DEV_FD
 326         { "floppy=", floppy_setup },
 327 #endif
 328 #ifdef CONFIG_CDU31A
 329         { "cdu31a=", cdu31a_setup },
 330 #endif CONFIG_CDU31A
 331 #ifdef CONFIG_MCD
 332         { "mcd=", mcd_setup },
 333 #endif CONFIG_MCD
 334 #ifdef CONFIG_MCDX
 335         { "mcdx=", mcdx_setup },
 336 #endif CONFIG_MCDX
 337 #ifdef CONFIG_SBPCD
 338         { "sbpcd=", sbpcd_setup },
 339 #endif CONFIG_SBPCD
 340 #ifdef CONFIG_AZTCD
 341         { "aztcd=", aztcd_setup },
 342 #endif CONFIG_AZTCD
 343 #ifdef CONFIG_CDU535
 344         { "sonycd535=", sonycd535_setup },
 345 #endif CONFIG_CDU535
 346 #ifdef CONFIG_GSCD
 347         { "gscd=", gscd_setup },
 348 #endif CONFIG_GSCD
 349 #ifdef CONFIG_CM206
 350         { "cm206=", cm206_setup },
 351 #endif CONFIG_CM206
 352 #ifdef CONFIG_OPTCD
 353         { "optcd=", optcd_setup },
 354 #endif CONFIG_OPTCD
 355 #ifdef CONFIG_SJCD
 356         { "sjcd=", sjcd_setup },
 357 #endif CONFIG_SJCD
 358 #ifdef CONFIG_ISP16_CDI
 359         { "isp16=", isp16_setup },
 360 #endif CONFIG_ISP16_CDI
 361 #ifdef CONFIG_SOUND
 362         { "sound=", sound_setup },
 363 #endif
 364 #ifdef CONFIG_ISDN_DRV_ICN
 365         { "icn=", icn_setup },
 366 #endif
 367 #ifdef CONFIG_ISDN_DRV_TELES
 368         { "teles=", teles_setup },
 369 #endif
 370 #ifdef CONFIG_ISDN_DRV_PCBIT
 371         { "pcbit=", pcbit_setup },
 372 #endif
 373 #ifdef CONFIG_ATARIMOUSE
 374         { "atamouse=", atari_mouse_setup },
 375 #endif
 376 #ifdef CONFIG_DMASOUND
 377         { "dmasound=", dmasound_setup },
 378 #endif
 379 #ifdef CONFIG_ATARI_SCSI
 380         { "atascsi=", atari_scsi_setup },
 381 #endif
 382 #if defined(CONFIG_A3000_SCSI) || defined(CONFIG_A2091_SCSI) \
 383             || defined(CONFIG_GVP11_SCSI)
 384         { "wd33c93=", wd33c93_setup },
 385 #endif
 386 #if defined(CONFIG_GVP11_SCSI)
 387         { "gvp11=", gvp11_setup },
 388 #endif
 389 #ifdef CONFIG_DIGI
 390         { "digi=", pcxx_setup },
 391 #endif
 392 #ifdef CONFIG_RISCOM8
 393         { "riscom8=", riscom8_setup },
 394 #endif
 395         { 0, 0 }
 396 };
 397 
 398 #ifdef CONFIG_BLK_DEV_RAM
 399 static void ramdisk_start_setup(char *str, int *ints)
     /*  */
 400 {
 401    if (ints[0] > 0 && ints[1] >= 0)
 402       rd_image_start = ints[1];
 403 }
 404 
 405 static void load_ramdisk(char *str, int *ints)
     /*  */
 406 {
 407    if (ints[0] > 0 && ints[1] >= 0)
 408       rd_doload = ints[1] & 1;
 409 }
 410 
 411 static void prompt_ramdisk(char *str, int *ints)
     /*  */
 412 {
 413    if (ints[0] > 0 && ints[1] >= 0)
 414       rd_prompt = ints[1] & 1;
 415 }
 416 
 417 static void ramdisk_size(char *str, int *ints)
     /*  */
 418 {
 419         if (ints[0] > 0 && ints[1] >= 0)
 420                 rd_size = ints[1];
 421 }
 422 
 423 #endif
 424 
 425 static int checksetup(char *line)
     /*  */
 426 {
 427         int i = 0;
 428         int ints[11];
 429 
 430 #ifdef CONFIG_BLK_DEV_IDE
 431         /* ide driver needs the basic string, rather than pre-processed values */
 432         if (!strncmp(line,"ide",3) || (!strncmp(line,"hd",2) && line[2] != '=')) {
 433                 ide_setup(line);
 434                 return 1;
 435         }
 436 #endif
 437         while (bootsetups[i].str) {
 438                 int n = strlen(bootsetups[i].str);
 439                 if (!strncmp(line,bootsetups[i].str,n)) {
 440                         bootsetups[i].setup_func(get_options(line+n,ints), ints);
 441                         return 1;
 442                 }
 443                 i++;
 444         }
 445         return 0;
 446 }
 447 
 448 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
 449    still work even if initially too large, it will just take slightly longer */
 450 unsigned long loops_per_sec = (1<<12);
 451 
 452 /* This is the number of bits of precision for the loops_per_second.  Each
 453    bit takes on average 1.5/HZ seconds.  This (like the original) is a little
 454    better than 1% */
 455 #define LPS_PREC 8
 456 
 457 void calibrate_delay(void)
     /*  */
 458 {
 459         int ticks;
 460         int loopbit;
 461         int lps_precision = LPS_PREC;
 462 
 463         loops_per_sec = (1<<12);
 464 
 465         printk("Calibrating delay loop.. ");
 466         while (loops_per_sec <<= 1) {
 467                 /* wait for "start of" clock tick */
 468                 ticks = jiffies;
 469                 while (ticks == jiffies)
 470                         /* nothing */;
 471                 /* Go .. */
 472                 ticks = jiffies;
 473                 __delay(loops_per_sec);
 474                 ticks = jiffies - ticks;
 475                 if (ticks)
 476                         break;
 477                 }
 478 
 479 /* Do a binary approximation to get loops_per_second set to equal one clock
 480    (up to lps_precision bits) */
 481         loops_per_sec >>= 1;
 482         loopbit = loops_per_sec;
 483         while ( lps_precision-- && (loopbit >>= 1) ) {
 484                 loops_per_sec |= loopbit;
 485                 ticks = jiffies;
 486                 while (ticks == jiffies);
 487                 ticks = jiffies;
 488                 __delay(loops_per_sec);
 489                 if (jiffies != ticks)   /* longer than 1 tick */
 490                         loops_per_sec &= ~loopbit;
 491         }
 492 
 493 /* finally, adjust loops per second in terms of seconds instead of clocks */    
 494         loops_per_sec *= HZ;
 495 /* Round the value and print it */      
 496         printk("ok - %lu.%02lu BogoMIPS\n",
 497                 (loops_per_sec+2500)/500000,
 498                 ((loops_per_sec+2500)/5000) % 100);
 499 }
 500 
 501 static void parse_root_dev(char * line)
     /*  */
 502 {
 503         int base = 0;
 504         static struct dev_name_struct {
 505                 const char *name;
 506                 const int num;
 507         } devices[] = {
 508                 { "nfs",     0x00ff },
 509                 { "hda",     0x0300 },
 510                 { "hdb",     0x0340 },
 511                 { "hdc",     0x1600 },
 512                 { "hdd",     0x1640 },
 513                 { "sda",     0x0800 },
 514                 { "sdb",     0x0810 },
 515                 { "sdc",     0x0820 },
 516                 { "sdd",     0x0830 },
 517                 { "sde",     0x0840 },
 518                 { "fd",      0x0200 },
 519                 { "xda",     0x0d00 },
 520                 { "xdb",     0x0d40 },
 521                 { "ram",     0x0100 },
 522                 { "scd",     0x0b00 },
 523                 { "mcd",     0x1700 },
 524                 { "cdu535",  0x1800 },
 525                 { "aztcd",   0x1d00 },
 526                 { "cm206cd", 0x2000 },
 527                 { "gscd",    0x1000 },
 528                 { "sbpcd",   0x1900 },
 529                 { "sonycd",  0x1800 },
 530                 { NULL, 0 }
 531         };
 532 
 533         if (strncmp(line,"/dev/",5) == 0) {
 534                 struct dev_name_struct *dev = devices;
 535                 line += 5;
 536                 do {
 537                         int len = strlen(dev->name);
 538                         if (strncmp(line,dev->name,len) == 0) {
 539                                 line += len;
 540                                 base = dev->num;
 541                                 break;
 542                         }
 543                         dev++;
 544                 } while (dev->name);
 545         }
 546         ROOT_DEV = to_kdev_t(base + simple_strtoul(line,NULL,base?10:16));
 547 }
 548 
 549 /*
 550  * This is a simple kernel command line parsing function: it parses
 551  * the command line, and fills in the arguments/environment to init
 552  * as appropriate. Any cmd-line option is taken to be an environment
 553  * variable if it contains the character '='.
 554  *
 555  *
 556  * This routine also checks for options meant for the kernel.
 557  * These options are not given to init - they are for internal kernel use only.
 558  */
 559 static void parse_options(char *line)
     /*  */
 560 {
 561         char *next;
 562         int args, envs;
 563 
 564         if (!*line)
 565                 return;
 566         args = 0;
 567         envs = 1;       /* TERM is set to 'linux' by default */
 568         next = line;
 569         while ((line = next) != NULL) {
 570                 if ((next = strchr(line,' ')) != NULL)
 571                         *next++ = 0;
 572                 /*
 573                  * check for kernel options first..
 574                  */
 575                 if (!strncmp(line,"root=",5)) {
 576                         parse_root_dev(line+5);
 577                         continue;
 578                 }
 579 #ifdef CONFIG_ROOT_NFS
 580                 if (!strncmp(line, "nfsroot=", 8)) {
 581                         int n;
 582                         line += 8;
 583                         ROOT_DEV = MKDEV(UNNAMED_MAJOR, 255);
 584                         if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
 585                                 strncpy(nfs_root_name, line, sizeof(nfs_root_name));
 586                                 nfs_root_name[sizeof(nfs_root_name)-1] = '\0';
 587                                 continue;
 588                         }
 589                         n = strlen(line) + strlen(NFS_ROOT);
 590                         if (n >= sizeof(nfs_root_name))
 591                                 line[sizeof(nfs_root_name) - strlen(NFS_ROOT) - 1] = '\0';
 592                         sprintf(nfs_root_name, NFS_ROOT, line);
 593                         continue;
 594                 }
 595                 if (!strncmp(line, "nfsaddrs=", 9)) {
 596                         line += 9;
 597                         strncpy(nfs_root_addrs, line, sizeof(nfs_root_addrs));
 598                         nfs_root_addrs[sizeof(nfs_root_addrs)-1] = '\0';
 599                         continue;
 600                 }
 601 #endif
 602                 if (!strcmp(line,"ro")) {
 603                         root_mountflags |= MS_RDONLY;
 604                         continue;
 605                 }
 606                 if (!strcmp(line,"rw")) {
 607                         root_mountflags &= ~MS_RDONLY;
 608                         continue;
 609                 }
 610                 if (!strcmp(line,"debug")) {
 611                         console_loglevel = 10;
 612                         continue;
 613                 }
 614                 if (!strncmp(line,"init=",5)) {
 615                         line += 5;
 616                         execute_command = line;
 617                         continue;
 618                 }
 619                 if (checksetup(line))
 620                         continue;
 621                 /*
 622                  * Then check if it's an environment variable or
 623                  * an option.
 624                  */
 625                 if (strchr(line,'=')) {
 626                         if (envs >= MAX_INIT_ENVS)
 627                                 break;
 628                         envp_init[++envs] = line;
 629                 } else {
 630                         if (args >= MAX_INIT_ARGS)
 631                                 break;
 632                         argv_init[++args] = line;
 633                 }
 634         }
 635         argv_init[args+1] = NULL;
 636         envp_init[envs+1] = NULL;
 637 }
 638 
 639 
 640 extern void setup_arch(char **, unsigned long *, unsigned long *);
 641 extern void arch_syms_export(void);
 642 
 643 #ifndef __SMP__
 644 
 645 /*
 646  *      Uniprocessor idle thread
 647  */
 648  
 649 int cpu_idle(void *unused)
     /*  */
 650 {
 651         for(;;)
 652                 idle();
 653 }
 654 
 655 #else
 656 
 657 /*
 658  *      Multiprocessor idle thread is in arch/...
 659  */
 660  
 661 extern int cpu_idle(void * unused);
 662 
 663 /*
 664  *      Activate a secondary processor.
 665  */
 666  
 667 asmlinkage void start_secondary(void)
     /*  */
 668 {
 669         trap_init();
 670         init_IRQ();
 671         smp_callin();
 672         cpu_idle(NULL);
 673 }
 674 
 675 
 676 
 677 /*
 678  *      Called by CPU#0 to activate the rest.
 679  */
 680  
 681 static void smp_init(void)
     /*  */
 682 {
 683         int i, j;
 684         smp_boot_cpus();
 685         
 686         /*
 687          *      Create the slave init tasks as sharing pid 0.
 688          *
 689          *      This should only happen if we have virtual CPU numbers
 690          *      higher than 0.
 691          */
 692 
 693         for (i=1; i<smp_num_cpus; i++)
 694         {
 695                 struct task_struct *n, *p;
 696 
 697                 j = cpu_logical_map[i];
 698                 /*
 699                  *      We use kernel_thread for the idlers which are
 700                  *      unlocked tasks running in kernel space.
 701                  */
 702                 kernel_thread(cpu_idle, NULL, CLONE_PID);
 703                 /*
 704                  *      Don't assume linear processor numbering
 705                  */
 706                 current_set[j]=task[i];
 707                 current_set[j]->processor=j;
 708                 cli();
 709                 n = task[i]->next_run;
 710                 p = task[i]->prev_run;
 711                 nr_running--;
 712                 n->prev_run = p;
 713                 p->next_run = n;
 714                 task[i]->next_run = task[i]->prev_run = task[i];
 715                 sti();
 716         }
 717 }               
 718 
 719 /*
 720  *      The autoprobe routines assume CPU#0 on the i386
 721  *      so we don't actually set the game in motion until
 722  *      they are finished.
 723  */
 724  
 725 static void smp_begin(void)
     /*  */
 726 {
 727         smp_threads_ready=1;
 728         smp_commence();
 729 }
 730         
 731 #endif
 732 
 733 /*
 734  *      Activate the first processor.
 735  */
 736  
 737 asmlinkage void start_kernel(void)
     /*  */
 738 {
 739         char * command_line;
 740 
 741 /*
 742  *      This little check will move.
 743  */
 744 
 745 #ifdef __SMP__
 746         static int first_cpu=1;
 747         
 748         if(!first_cpu)
 749                 start_secondary();
 750         first_cpu=0;
 751         
 752 #endif  
 753 /*
 754  * Interrupts are still disabled. Do necessary setups, then
 755  * enable them
 756  */
 757         setup_arch(&command_line, &memory_start, &memory_end);
 758         memory_start = paging_init(memory_start,memory_end);
 759         trap_init();
 760         init_IRQ();
 761         sched_init();
 762         time_init();
 763         parse_options(command_line);
 764 #ifdef CONFIG_MODULES
 765         init_modules();
 766 #endif
 767 #ifdef CONFIG_PROFILE
 768         if (!prof_shift)
 769 #ifdef CONFIG_PROFILE_SHIFT
 770                 prof_shift = CONFIG_PROFILE_SHIFT;
 771 #else
 772                 prof_shift = 2;
 773 #endif
 774 #endif
 775         if (prof_shift) {
 776                 prof_buffer = (unsigned int *) memory_start;
 777                 /* only text is profiled */
 778                 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
 779                 prof_len >>= prof_shift;
 780                 memory_start += prof_len * sizeof(unsigned int);
 781         }
 782         memory_start = console_init(memory_start,memory_end);
 783 #ifdef CONFIG_PCI
 784         memory_start = pci_init(memory_start,memory_end);
 785 #endif
 786         memory_start = kmalloc_init(memory_start,memory_end);
 787         sti();
 788         calibrate_delay();
 789         memory_start = inode_init(memory_start,memory_end);
 790         memory_start = file_table_init(memory_start,memory_end);
 791         memory_start = name_cache_init(memory_start,memory_end);
 792 #ifdef CONFIG_BLK_DEV_INITRD
 793         if (initrd_start && initrd_start < memory_start) {
 794                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 795                     "disabling it.\n",initrd_start,memory_start);
 796                 initrd_start = 0;
 797         }
 798 #endif
 799         mem_init(memory_start,memory_end);
 800         buffer_init();
 801         sock_init();
 802 #if defined(CONFIG_SYSVIPC) || defined(CONFIG_KERNELD)
 803         ipc_init();
 804 #endif
 805         dquot_init();
 806         arch_syms_export();
 807         sti();
 808         check_bugs();
 809 
 810         printk(linux_banner);
 811 #ifdef __SMP__
 812         smp_init();
 813 #endif
 814         sysctl_init();
 815         /* 
 816          *      We count on the initial thread going ok 
 817          *      Like idlers init is an unlocked kernel thread, which will
 818          *      make syscalls (and thus be locked).
 819          */
 820         kernel_thread(init, NULL, 0);
 821 /*
 822  * task[0] is meant to be used as an "idle" task: it may not sleep, but
 823  * it might do some general things like count free pages or it could be
 824  * used to implement a reasonable LRU algorithm for the paging routines:
 825  * anything that can be useful, but shouldn't take time from the real
 826  * processes.
 827  *
 828  * Right now task[0] just does a infinite idle loop.
 829  */
 830         cpu_idle(NULL);
 831 }
 832 
 833 static int printf(const char *fmt, ...)
     /*  */
 834 {
 835         va_list args;
 836         int i;
 837 
 838         va_start(args, fmt);
 839         write(1,printbuf,i=vsprintf(printbuf, fmt, args));
 840         va_end(args);
 841         return i;
 842 }
 843 
 844 static int do_rc(void * rc)
     /*  */
 845 {
 846         close(0);
 847         if (open(rc,O_RDONLY,0))
 848                 return -1;
 849         return execve("/bin/sh", argv_rc, envp_rc);
 850 }
 851 
 852 static int do_shell(void * shell)
     /*  */
 853 {
 854         close(0);close(1);close(2);
 855         setsid();
 856         (void) open("/dev/tty1",O_RDWR,0);
 857         (void) dup(0);
 858         (void) dup(0);
 859         return execve(shell, argv, envp);
 860 }
 861 
 862 #ifdef CONFIG_BLK_DEV_INITRD
 863 static int do_linuxrc(void * shell)
     /*  */
 864 {
 865         static char *argv[] = { "linuxrc", NULL, };
 866 
 867         close(0);close(1);close(2);
 868         setsid();
 869         (void) open("/dev/tty1",O_RDWR,0);
 870         (void) dup(0);
 871         (void) dup(0);
 872         return execve(shell, argv, envp_init);
 873 }
 874 
 875 static void no_initrd(char *s,int *ints)
     /*  */
 876 {
 877         mount_initrd = 0;
 878 }
 879 #endif
 880 
 881 static int init(void * unused)
     /*  */
 882 {
 883         int pid,i;
 884 #ifdef CONFIG_BLK_DEV_INITRD
 885         int real_root_mountflags;
 886 #endif
 887 
 888         /* Launch bdflush from here, instead of the old syscall way. */
 889         kernel_thread(bdflush, NULL, 0);
 890         /* Start the background pageout daemon. */
 891         kernel_thread(kswapd, NULL, 0);
 892 
 893 #ifdef CONFIG_BLK_DEV_INITRD
 894         real_root_dev = ROOT_DEV;
 895         real_root_mountflags = root_mountflags;
 896         if (initrd_start && mount_initrd) root_mountflags &= ~MS_RDONLY;
 897         else mount_initrd =0;
 898 #endif
 899         setup();
 900 
 901 #ifdef __SMP__
 902         /*
 903          *      With the devices probed and setup we can
 904          *      now enter SMP mode.
 905          */
 906         
 907         smp_begin();
 908 #endif  
 909 
 910         #ifdef CONFIG_UMSDOS_FS
 911         {
 912                 /*
 913                         When mounting a umsdos fs as root, we detect
 914                         the pseudo_root (/linux) and initialise it here.
 915                         pseudo_root is defined in fs/umsdos/inode.c
 916                 */
 917                 extern struct inode *pseudo_root;
 918                 if (pseudo_root != NULL){
 919                         current->fs->root = pseudo_root;
 920                         current->fs->pwd  = pseudo_root;
 921                 }
 922         }
 923         #endif
 924 
 925 #ifdef CONFIG_BLK_DEV_INITRD
 926         root_mountflags = real_root_mountflags;
 927         if (mount_initrd && ROOT_DEV != real_root_dev && ROOT_DEV == MKDEV(RAMDISK_MAJOR,0)) {
 928                 int error;
 929 
 930                 pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
 931                 if (pid>0)
 932                         while (pid != wait(&i));
 933                 if (real_root_dev != MKDEV(RAMDISK_MAJOR, 0)) {
 934                         error = change_root(real_root_dev,"/initrd");
 935                         if (error)
 936                                 printk(KERN_ERR "Change root to /initrd: "
 937                                     "error %d\n",error);
 938                 }
 939         }
 940 #endif
 941 
 942         (void) open("/dev/tty1",O_RDWR,0);
 943         (void) dup(0);
 944         (void) dup(0);
 945 
 946         if (!execute_command) {
 947                 execve("/etc/init",argv_init,envp_init);
 948                 execve("/bin/init",argv_init,envp_init);
 949                 execve("/sbin/init",argv_init,envp_init);
 950                 /* if this fails, fall through to original stuff */
 951 
 952                 pid = kernel_thread(do_rc, "/etc/rc", SIGCHLD);
 953                 if (pid>0)
 954                         while (pid != wait(&i))
 955                                 /* nothing */;
 956         }
 957 
 958         while (1) {
 959                 pid = kernel_thread(do_shell,
 960                         execute_command ? execute_command : "/bin/sh",
 961                         SIGCHLD);
 962                 if (pid < 0) {
 963                         printf("Fork failed in init\n\r");
 964                         continue;
 965                 }
 966                 while (1)
 967                         if (pid == wait(&i))
 968                                 break;
 969                 printf("\n\rchild %d died with code %04x\n\r",pid,i);
 970                 sync();
 971         }
 972         return -1;
 973 }
/* */
root/init/main.c

DEFINITIONS
