root/init/main.c

/* */

DEFINITIONS

1. _syscall0
2. get_options
3. checksetup
4. calibrate_delay
5. parse_options
6. copy_options
7. copro_timeout
8. start_kernel
9. printf
10. init

   1 /*
   2  *  linux/init/main.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 #include <stdarg.h>
   8 
   9 #include <asm/system.h>
  10 #include <asm/io.h>
  11 
  12 #include <linux/types.h>
  13 #include <linux/fcntl.h>
  14 #include <linux/config.h>
  15 #include <linux/sched.h>
  16 #include <linux/tty.h>
  17 #include <linux/head.h>
  18 #include <linux/unistd.h>
  19 #include <linux/string.h>
  20 #include <linux/timer.h>
  21 #include <linux/fs.h>
  22 #include <linux/ctype.h>
  23 #include <linux/delay.h>
  24 #include <linux/utsname.h>
  25 #include <linux/ioport.h>
  26 
  27 extern unsigned long * prof_buffer;
  28 extern unsigned long prof_len;
  29 extern char edata, end;
  30 extern char *linux_banner;
  31 asmlinkage void lcall7(void);
  32 struct desc_struct default_ldt;
  33 
  34 /*
  35  * we need this inline - forking from kernel space will result
  36  * in NO COPY ON WRITE (!!!), until an execve is executed. This
  37  * is no problem, but for the stack. This is handled by not letting
  38  * main() use the stack at all after fork(). Thus, no function
  39  * calls - which means inline code for fork too, as otherwise we
  40  * would use the stack upon exit from 'fork()'.
  41  *
  42  * Actually only pause and fork are needed inline, so that there
  43  * won't be any messing with the stack from main(), but we define
  44  * some others too.
  45  */
  46 #define __NR__exit __NR_exit
  47 static inline _syscall0(int,idle)
     /*  */
  48 static inline _syscall0(int,fork)
  49 static inline _syscall0(int,pause)
  50 static inline _syscall0(int,setup)
  51 static inline _syscall0(int,sync)
  52 static inline _syscall0(pid_t,setsid)
  53 static inline _syscall3(int,write,int,fd,const char *,buf,off_t,count)
  54 static inline _syscall1(int,dup,int,fd)
  55 static inline _syscall3(int,execve,const char *,file,char **,argv,char **,envp)
  56 static inline _syscall3(int,open,const char *,file,int,flag,int,mode)
  57 static inline _syscall1(int,close,int,fd)
  58 static inline _syscall1(int,_exit,int,exitcode)
  59 static inline _syscall3(pid_t,waitpid,pid_t,pid,int *,wait_stat,int,options)
  60 
  61 static inline pid_t wait(int * wait_stat)
  62 {
  63         return waitpid(-1,wait_stat,0);
  64 }
  65 
  66 static char printbuf[1024];
  67 
  68 extern int console_loglevel;
  69 
  70 extern char empty_zero_page[PAGE_SIZE];
  71 extern int vsprintf(char *,const char *,va_list);
  72 extern void init(void);
  73 extern void init_IRQ(void);
  74 extern long kmalloc_init (long,long);
  75 extern long blk_dev_init(long,long);
  76 extern long chr_dev_init(long,long);
  77 extern void floppy_init(void);
  78 extern void sock_init(void);
  79 extern long rd_init(long mem_start, int length);
  80 unsigned long net_dev_init(unsigned long, unsigned long);
  81 
  82 extern void hd_setup(char *str, int *ints);
  83 extern void bmouse_setup(char *str, int *ints);
  84 extern void eth_setup(char *str, int *ints);
  85 extern void xd_setup(char *str, int *ints);
  86 extern void mcd_setup(char *str, int *ints);
  87 extern void st0x_setup(char *str, int *ints);
  88 extern void tmc8xx_setup(char *str, int *ints);
  89 extern void t128_setup(char *str, int *ints);
  90 extern void generic_NCR5380_setup(char *str, int *intr);
  91 extern void aha152x_setup(char *str, int *ints);
  92 extern void sound_setup(char *str, int *ints);
  93 #ifdef CONFIG_SBPCD
  94 extern void sbpcd_setup(char *str, int *ints);
  95 #endif CONFIG_SBPCD
  96 
  97 #ifdef CONFIG_SYSVIPC
  98 extern void ipc_init(void);
  99 #endif
 100 #ifdef CONFIG_SCSI
 101 extern unsigned long scsi_dev_init(unsigned long, unsigned long);
 102 #endif
 103 
 104 /*
 105  * This is set up by the setup-routine at boot-time
 106  */
 107 #define PARAM   empty_zero_page
 108 #define EXT_MEM_K (*(unsigned short *) (PARAM+2))
 109 #define DRIVE_INFO (*(struct drive_info_struct *) (PARAM+0x80))
 110 #define SCREEN_INFO (*(struct screen_info *) (PARAM+0))
 111 #define MOUNT_ROOT_RDONLY (*(unsigned short *) (PARAM+0x1F2))
 112 #define RAMDISK_SIZE (*(unsigned short *) (PARAM+0x1F8))
 113 #define ORIG_ROOT_DEV (*(unsigned short *) (PARAM+0x1FC))
 114 #define AUX_DEVICE_INFO (*(unsigned char *) (PARAM+0x1FF))
 115 
 116 /*
 117  * Boot command-line arguments
 118  */
 119 #define MAX_INIT_ARGS 8
 120 #define MAX_INIT_ENVS 8
 121 #define COMMAND_LINE ((char *) (PARAM+2048))
 122 #define COMMAND_LINE_SIZE 256
 123 
 124 extern void time_init(void);
 125 
 126 static unsigned long memory_start = 0;  /* After mem_init, stores the */
 127                                         /* amount of free user memory */
 128 static unsigned long memory_end = 0;
 129 static unsigned long low_memory_start = 0;
 130 
 131 static char term[21];
 132 int rows, cols;
 133 
 134 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 135 static char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", term, NULL, };
 136 
 137 static char * argv_rc[] = { "/bin/sh", NULL };
 138 static char * envp_rc[] = { "HOME=/", term, NULL };
 139 
 140 static char * argv[] = { "-/bin/sh",NULL };
 141 static char * envp[] = { "HOME=/usr/root", term, NULL };
 142 
 143 struct drive_info_struct { char dummy[32]; } drive_info;
 144 struct screen_info screen_info;
 145 
 146 unsigned char aux_device_present;
 147 int ramdisk_size;
 148 int root_mountflags = 0;
 149 
 150 static char fpu_error = 0;
 151 
 152 static char command_line[COMMAND_LINE_SIZE] = { 0, };
 153 
 154 char *get_options(char *str, int *ints) 
     /*  */
 155 {
 156         char *cur = str;
 157         int i=1;
 158 
 159         while (cur && isdigit(*cur) && i <= 10) {
 160                 ints[i++] = simple_strtoul(cur,NULL,0);
 161                 if ((cur = strchr(cur,',')) != NULL)
 162                         cur++;
 163         }
 164         ints[0] = i-1;
 165         return(cur);
 166 }
 167 
 168 struct {
 169         char *str;
 170         void (*setup_func)(char *, int *);
 171 } bootsetups[] = {
 172         { "reserve=", reserve_setup },
 173 #ifdef CONFIG_INET
 174         { "ether=", eth_setup },
 175 #endif
 176 #ifdef CONFIG_BLK_DEV_HD
 177         { "hd=", hd_setup },
 178 #endif
 179 #ifdef CONFIG_BUSMOUSE
 180         { "bmouse=", bmouse_setup },
 181 #endif
 182 #ifdef CONFIG_SCSI_SEAGATE
 183         { "st0x=", st0x_setup },
 184         { "tmc8xx=", tmc8xx_setup },
 185 #endif
 186 #ifdef CONFIG_SCSI_T128
 187         { "t128=", t128_setup },
 188 #endif
 189 #ifdef CONFIG_SCSI_GENERIC_NCR5380
 190         { "ncr5380=", generic_NCR5380_setup },
 191 #endif
 192 #ifdef CONFIG_SCSI_AHA152X
 193         { "aha152x=", aha152x_setup},
 194 #endif
 195 #ifdef CONFIG_BLK_DEV_XD
 196         { "xd=", xd_setup },
 197 #endif
 198 #ifdef CONFIG_MCD
 199         { "mcd=", mcd_setup },
 200 #endif
 201 #ifdef CONFIG_SOUND
 202         { "sound=", sound_setup },
 203 #endif
 204 #ifdef CONFIG_SBPCD
 205         { "sbpcd=", sbpcd_setup },
 206 #endif CONFIG_SBPCD
 207         { 0, 0 }
 208 };
 209 
 210 int checksetup(char *line)
     /*  */
 211 {
 212         int i = 0;
 213         int ints[11];
 214 
 215         while (bootsetups[i].str) {
 216                 int n = strlen(bootsetups[i].str);
 217                 if (!strncmp(line,bootsetups[i].str,n)) {
 218                         bootsetups[i].setup_func(get_options(line+n,ints), ints);
 219                         return(0);
 220                 }
 221                 i++;
 222         }
 223         return(1);
 224 }
 225 
 226 unsigned long loops_per_sec = 1;
 227 
 228 static void calibrate_delay(void)
     /*  */
 229 {
 230         int ticks;
 231 
 232         printk("Calibrating delay loop.. ");
 233         while (loops_per_sec <<= 1) {
 234                 ticks = jiffies;
 235                 __delay(loops_per_sec);
 236                 ticks = jiffies - ticks;
 237                 if (ticks >= HZ) {
 238                         __asm__("mull %1 ; divl %2"
 239                                 :"=a" (loops_per_sec)
 240                                 :"d" (HZ),
 241                                  "r" (ticks),
 242                                  "0" (loops_per_sec)
 243                                 :"dx");
 244                         printk("ok - %lu.%02lu BogoMips\n",
 245                                 loops_per_sec/500000,
 246                                 (loops_per_sec/5000) % 100);
 247                         return;
 248                 }
 249         }
 250         printk("failed\n");
 251 }
 252         
 253 
 254 /*
 255  * This is a simple kernel command line parsing function: it parses
 256  * the command line, and fills in the arguments/environment to init
 257  * as appropriate. Any cmd-line option is taken to be an environment
 258  * variable if it contains the character '='.
 259  *
 260  *
 261  * This routine also checks for options meant for the kernel - currently
 262  * only the "root=XXXX" option is recognized. These options are not given
 263  * to init - they are for internal kernel use only.
 264  */
 265 static void parse_options(char *line)
     /*  */
 266 {
 267         char *next;
 268         char *devnames[] = { "hda", "hdb", "sda", "sdb", "sdc", "sdd", "sde", "fd", "xda", "xdb", NULL };
 269         int devnums[]    = { 0x300, 0x340, 0x800, 0x810, 0x820, 0x830, 0x840, 0x200, 0xD00, 0xD40, 0};
 270         int args, envs;
 271 
 272         if (!*line)
 273                 return;
 274         args = 0;
 275         envs = 1;       /* TERM is set to 'console' by default */
 276         next = line;
 277         while ((line = next) != NULL) {
 278                 if ((next = strchr(line,' ')) != NULL)
 279                         *next++ = 0;
 280                 /*
 281                  * check for kernel options first..
 282                  */
 283                 if (!strncmp(line,"root=",5)) {
 284                         int n;
 285                         line += 5;
 286                         if (strncmp(line,"/dev/",5)) {
 287                                 ROOT_DEV = simple_strtoul(line,NULL,16);
 288                                 continue;
 289                         }
 290                         line += 5;
 291                         for (n = 0 ; devnames[n] ; n++) {
 292                                 int len = strlen(devnames[n]);
 293                                 if (!strncmp(line,devnames[n],len)) {
 294                                         ROOT_DEV = devnums[n]+simple_strtoul(line+len,NULL,16);
 295                                         break;
 296                                 }
 297                         }
 298                 } else if (!strcmp(line,"ro"))
 299                         root_mountflags |= MS_RDONLY;
 300                 else if (!strcmp(line,"rw"))
 301                         root_mountflags &= ~MS_RDONLY;
 302                 else if (!strcmp(line,"debug"))
 303                         console_loglevel = 10;
 304                 else if (!strcmp(line,"no387")) {
 305                         hard_math = 0;
 306                         __asm__("movl %%cr0,%%eax\n\t"
 307                                 "orl $0xE,%%eax\n\t"
 308                                 "movl %%eax,%%cr0\n\t" : : : "ax");
 309                 } else
 310                         checksetup(line);
 311                 /*
 312                  * Then check if it's an environment variable or
 313                  * an option.
 314                  */     
 315                 if (strchr(line,'=')) {
 316                         if (envs >= MAX_INIT_ENVS)
 317                                 break;
 318                         envp_init[++envs] = line;
 319                 } else {
 320                         if (args >= MAX_INIT_ARGS)
 321                                 break;
 322                         argv_init[++args] = line;
 323                 }
 324         }
 325         argv_init[args+1] = NULL;
 326         envp_init[envs+1] = NULL;
 327 }
 328 
 329 static void copy_options(char * to, char * from)
     /*  */
 330 {
 331         char c = ' ';
 332         int len = 0;
 333 
 334         for (;;) {
 335                 if (c == ' ' && *(unsigned long *)from == *(unsigned long *)"mem=")
 336                         memory_end = simple_strtoul(from+4, &from, 0);
 337                 c = *(from++);
 338                 if (!c)
 339                         break;
 340                 if (COMMAND_LINE_SIZE <= ++len)
 341                         break;
 342                 *(to++) = c;
 343         }
 344         *to = '\0';
 345 }
 346 
 347 static void copro_timeout(void)
     /*  */
 348 {
 349         fpu_error = 1;
 350         timer_table[COPRO_TIMER].expires = jiffies+100;
 351         timer_active |= 1<<COPRO_TIMER;
 352         printk("387 failed: trying to reset\n");
 353         send_sig(SIGFPE, last_task_used_math, 1);
 354         outb_p(0,0xf1);
 355         outb_p(0,0xf0);
 356 }
 357 
 358 asmlinkage void start_kernel(void)
     /*  */
 359 {
 360 /*
 361  * Interrupts are still disabled. Do necessary setups, then
 362  * enable them
 363  */
 364         set_call_gate(&default_ldt,lcall7);
 365         ROOT_DEV = ORIG_ROOT_DEV;
 366         drive_info = DRIVE_INFO;
 367         screen_info = SCREEN_INFO;
 368         aux_device_present = AUX_DEVICE_INFO;
 369         memory_end = (1<<20) + (EXT_MEM_K<<10);
 370         memory_end &= PAGE_MASK;
 371         ramdisk_size = RAMDISK_SIZE;
 372         copy_options(command_line,COMMAND_LINE);
 373 #ifdef CONFIG_MAX_16M
 374         if (memory_end > 16*1024*1024)
 375                 memory_end = 16*1024*1024;
 376 #endif
 377         if (MOUNT_ROOT_RDONLY)
 378                 root_mountflags |= MS_RDONLY;
 379         if ((unsigned long)&end >= (1024*1024)) {
 380                 memory_start = (unsigned long) &end;
 381                 low_memory_start = PAGE_SIZE;
 382         } else {
 383                 memory_start = 1024*1024;
 384                 low_memory_start = (unsigned long) &end;
 385         }
 386         low_memory_start = PAGE_ALIGN(low_memory_start);
 387         memory_start = paging_init(memory_start,memory_end);
 388         if (strncmp((char*)0x0FFFD9, "EISA", 4) == 0)
 389                 EISA_bus = 1;
 390         trap_init();
 391         init_IRQ();
 392         sched_init();
 393         parse_options(command_line);
 394 #ifdef CONFIG_PROFILE
 395         prof_buffer = (unsigned long *) memory_start;
 396         prof_len = (unsigned long) &end;
 397         prof_len >>= 2;
 398         memory_start += prof_len * sizeof(unsigned long);
 399 #endif
 400         memory_start = kmalloc_init(memory_start,memory_end);
 401         memory_start = chr_dev_init(memory_start,memory_end);
 402         memory_start = blk_dev_init(memory_start,memory_end);
 403         sti();
 404         calibrate_delay();
 405 #ifdef CONFIG_INET
 406         memory_start = net_dev_init(memory_start,memory_end);
 407 #endif
 408 #ifdef CONFIG_SCSI
 409         memory_start = scsi_dev_init(memory_start,memory_end);
 410 #endif
 411         memory_start = inode_init(memory_start,memory_end);
 412         memory_start = file_table_init(memory_start,memory_end);
 413         mem_init(low_memory_start,memory_start,memory_end);
 414         buffer_init();
 415         time_init();
 416         floppy_init();
 417         sock_init();
 418 #ifdef CONFIG_SYSVIPC
 419         ipc_init();
 420 #endif
 421         sti();
 422         
 423         /*
 424          * check if exception 16 works correctly.. This is truly evil
 425          * code: it disables the high 8 interrupts to make sure that
 426          * the irq13 doesn't happen. But as this will lead to a lockup
 427          * if no exception16 arrives, it depends on the fact that the
 428          * high 8 interrupts will be re-enabled by the next timer tick.
 429          * So the irq13 will happen eventually, but the exception 16
 430          * should get there first..
 431          */
 432         if (hard_math) {
 433                 unsigned short control_word;
 434 
 435                 printk("Checking 386/387 coupling... ");
 436                 timer_table[COPRO_TIMER].expires = jiffies+50;
 437                 timer_table[COPRO_TIMER].fn = copro_timeout;
 438                 timer_active |= 1<<COPRO_TIMER;
 439                 __asm__("clts ; fninit ; fnstcw %0 ; fwait":"=m" (*&control_word));
 440                 control_word &= 0xffc0;
 441                 __asm__("fldcw %0 ; fwait": :"m" (*&control_word));
 442                 outb_p(inb_p(0x21) | (1 << 2), 0x21);
 443                 __asm__("fldz ; fld1 ; fdiv %st,%st(1) ; fwait");
 444                 timer_active &= ~(1<<COPRO_TIMER);
 445                 if (!fpu_error)
 446                         printk("Ok, fpu using %s error reporting.\n",
 447                                 ignore_irq13?"exception 16":"irq13");
 448         }
 449 #ifndef CONFIG_MATH_EMULATION
 450         else {
 451                 printk("No coprocessor found and no math emulation present.\n");
 452                 printk("Giving up.\n");
 453                 for (;;) ;
 454         }
 455 #endif
 456 
 457         system_utsname.machine[1] = '0' + x86;
 458         printk(linux_banner);
 459 
 460         move_to_user_mode();
 461         if (!fork())            /* we count on this going ok */
 462                 init();
 463 /*
 464  * task[0] is meant to be used as an "idle" task: it may not sleep, but
 465  * it might do some general things like count free pages or it could be
 466  * used to implement a reasonable LRU algorithm for the paging routines:
 467  * anything that can be useful, but shouldn't take time from the real
 468  * processes.
 469  *
 470  * Right now task[0] just does a infinite idle loop.
 471  */
 472         for(;;)
 473                 idle();
 474 }
 475 
 476 static int printf(const char *fmt, ...)
     /*  */
 477 {
 478         va_list args;
 479         int i;
 480 
 481         va_start(args, fmt);
 482         write(1,printbuf,i=vsprintf(printbuf, fmt, args));
 483         va_end(args);
 484         return i;
 485 }
 486 
 487 void init(void)
     /*  */
 488 {
 489         int pid,i;
 490 
 491         setup();
 492         sprintf(term, "TERM=con%dx%d", ORIG_VIDEO_COLS, ORIG_VIDEO_LINES);
 493         (void) open("/dev/tty1",O_RDWR,0);
 494         (void) dup(0);
 495         (void) dup(0);
 496 
 497         execve("/etc/init",argv_init,envp_init);
 498         execve("/bin/init",argv_init,envp_init);
 499         execve("/sbin/init",argv_init,envp_init);
 500         /* if this fails, fall through to original stuff */
 501 
 502         if (!(pid=fork())) {
 503                 close(0);
 504                 if (open("/etc/rc",O_RDONLY,0))
 505                         _exit(1);
 506                 execve("/bin/sh",argv_rc,envp_rc);
 507                 _exit(2);
 508         }
 509         if (pid>0)
 510                 while (pid != wait(&i))
 511                         /* nothing */;
 512         while (1) {
 513                 if ((pid = fork()) < 0) {
 514                         printf("Fork failed in init\n\r");
 515                         continue;
 516                 }
 517                 if (!pid) {
 518                         close(0);close(1);close(2);
 519                         setsid();
 520                         (void) open("/dev/tty1",O_RDWR,0);
 521                         (void) dup(0);
 522                         (void) dup(0);
 523                         _exit(execve("/bin/sh",argv,envp));
 524                 }
 525                 while (1)
 526                         if (pid == wait(&i))
 527                                 break;
 528                 printf("\n\rchild %d died with code %04x\n\r",pid,i);
 529                 sync();
 530         }
 531         _exit(0);
 532 }

/* */