kernel/start.c

   1
   2 /* First C file used by the kernel. */
   3
   4 #include "kernel.h"
   5 #include "proc.h"
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include "proto.h"
   9
  10 #ifdef CONFIG_WATCHDOG
  11 #include "watchdog.h"
  12 #endif
  13
  14 /*===========================================================================*
  15  *                              cstart                                       *
  16  *===========================================================================*/
  17 PUBLIC void cstart(
  18    u16_t cs,            /* kernel code segment */
  19    u16_t ds,            /* kernel data segment */
  20    u16_t mds,           /* monitor data segment */
  21    u16_t parmoff,       /* boot parameters offset */
  22    u16_t parmsize       /* boot parameters length */
  23 )
  24 {
  25 /* Perform system initializations prior to calling main(). Most settings are
  26  * determined with help of the environment strings passed by MINIX' loader.
  27  */
  28   register char *value;                         /* value in key=value pair */
  29   extern int etext, end;
  30   int h;
  31
  32   /* Record where the kernel and the monitor are. */
  33   kinfo.code_base = seg2phys(cs);
  34   kinfo.code_size = (phys_bytes) &etext;        /* size of code segment */
  35   kinfo.data_base = seg2phys(ds);
  36   kinfo.data_size = (phys_bytes) &end;          /* size of data segment */
  37
  38   /* protection initialization */
  39   prot_init();
  40
  41   /* Copy the boot parameters to the local buffer. */
  42   arch_get_params(params_buffer, sizeof(params_buffer));
  43
  44   /* determine verbosity */
  45   if ((value = env_get(VERBOSEBOOTVARNAME)))
  46           verboseboot = atoi(value);
  47
  48   DEBUGEXTRA(("cstart\n"));
  49
  50   /* Record miscellaneous information for user-space servers. */
  51   kinfo.nr_procs = NR_PROCS;
  52   kinfo.nr_tasks = NR_TASKS;
  53   strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
  54   kinfo.release[sizeof(kinfo.release)-1] = '\0';
  55   strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
  56   kinfo.version[sizeof(kinfo.version)-1] = '\0';
  57   kinfo.proc_addr = (vir_bytes) proc;
  58
  59   /* Load average data initialization. */
  60   kloadinfo.proc_last_slot = 0;
  61   for(h = 0; h < _LOAD_HISTORY; h++)
  62         kloadinfo.proc_load_history[h] = 0;
  63
  64   /* Processor? Decide if mode is protected for older machines. */
  65   machine.processor=atoi(env_get("processor"));
  66
  67   /* XT, AT or MCA bus? */
  68   value = env_get("bus");
  69   if (value == NULL || strcmp(value, "at") == 0) {
  70       machine.pc_at = TRUE;                     /* PC-AT compatible hardware */
  71   } else if (strcmp(value, "mca") == 0) {
  72       machine.pc_at = machine.ps_mca = TRUE;    /* PS/2 with micro channel */
  73   }
  74
  75   /* Type of VDU: */
  76   value = env_get("video");     /* EGA or VGA video unit */
  77   if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
  78   if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
  79
  80   /* Get clock tick frequency. */
  81   value = env_get("hz");
  82   if(value)
  83         system_hz = atoi(value);
  84   if(!value || system_hz < 2 || system_hz > 50000)      /* sanity check */
  85         system_hz = DEFAULT_HZ;
  86   value = env_get(SERVARNAME);
  87   if(value && atoi(value) == 0)
  88         do_serial_debug=1;
  89
  90 #ifdef CONFIG_APIC
  91   value = env_get("no_apic");
  92   if(value)
  93         config_no_apic = atoi(value);
  94   else
  95         config_no_apic = 1;
  96 #endif
  97
  98 #ifdef CONFIG_WATCHDOG
  99   value = env_get("watchdog");
 100   if (value)
 101           watchdog_enabled = atoi(value);
 102 #endif
 103
 104   /* Return to assembler code to switch to protected mode (if 286),
 105    * reload selectors and call main().
 106    */
 107
 108   DEBUGEXTRA(("intr_init(%d, 0)\n", INTS_MINIX));
 109   intr_init(INTS_MINIX, 0);
 110 }
 111
 112 /*===========================================================================*
 113  *                              get_value                                    *
 114  *===========================================================================*/
 115
 116 PRIVATE char *get_value(
 117   const char *params,                   /* boot monitor parameters */
 118   const char *name                      /* key to look up */
 119 )
 120 {
 121 /* Get environment value - kernel version of getenv to avoid setting up the
 122  * usual environment array.
 123  */
 124   register const char *namep;
 125   register char *envp;
 126
 127   for (envp = (char *) params; *envp != 0;) {
 128         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
 129                 ;
 130         if (*namep == '\0' && *envp == '=') return(envp + 1);
 131         while (*envp++ != 0)
 132                 ;
 133   }
 134   return(NULL);
 135 }
 136
 137 /*===========================================================================*
 138  *                              env_get                                 *
 139  *===========================================================================*/
 140 PUBLIC char *env_get(const char *name)
 141 {
 142         return get_value(params_buffer, name);
 143 }
 144