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 FORWARD _PROTOTYPE( char *get_value, (_CONST char *params, _CONST char *key));
  15 /*===========================================================================*
  16  *                              cstart                                       *
  17  *===========================================================================*/
  18 PUBLIC void cstart(cs, ds, mds, parmoff, parmsize)
  19 U16_t cs, ds;                   /* kernel code and data segment */
  20 U16_t mds;                      /* monitor data segment */
  21 U16_t parmoff, parmsize;        /* boot parameters offset and length */
  22 {
  23 /* Perform system initializations prior to calling main(). Most settings are
  24  * determined with help of the environment strings passed by MINIX' loader.
  25  */
  26   register char *value;                         /* value in key=value pair */
  27   extern int etext, end;
  28   int h;
  29
  30   /* Record where the kernel and the monitor are. */
  31   kinfo.code_base = seg2phys(cs);
  32   kinfo.code_size = (phys_bytes) &etext;        /* size of code segment */
  33   kinfo.data_base = seg2phys(ds);
  34   kinfo.data_size = (phys_bytes) &end;          /* size of data segment */
  35
  36   /* protection initialization */
  37   prot_init();
  38
  39   /* Copy the boot parameters to the local buffer. */
  40   arch_get_params(params_buffer, sizeof(params_buffer));
  41
  42   /* determine verbosity */
  43   if ((value = get_value(params_buffer, VERBOSEBOOTVARNAME)))
  44           verboseboot = atoi(value);
  45
  46   DEBUGMAX(("cstart\n"));
  47
  48   /* Record miscellaneous information for user-space servers. */
  49   kinfo.nr_procs = NR_PROCS;
  50   kinfo.nr_tasks = NR_TASKS;
  51   strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
  52   kinfo.release[sizeof(kinfo.release)-1] = '\0';
  53   strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
  54   kinfo.version[sizeof(kinfo.version)-1] = '\0';
  55   kinfo.proc_addr = (vir_bytes) proc;
  56
  57   /* Load average data initialization. */
  58   kloadinfo.proc_last_slot = 0;
  59   for(h = 0; h < _LOAD_HISTORY; h++)
  60         kloadinfo.proc_load_history[h] = 0;
  61
  62   /* Processor? Decide if mode is protected for older machines. */
  63   machine.processor=atoi(get_value(params_buffer, "processor"));
  64
  65   /* XT, AT or MCA bus? */
  66   value = get_value(params_buffer, "bus");
  67   if (value == NIL_PTR || strcmp(value, "at") == 0) {
  68       machine.pc_at = TRUE;                     /* PC-AT compatible hardware */
  69   } else if (strcmp(value, "mca") == 0) {
  70       machine.pc_at = machine.ps_mca = TRUE;    /* PS/2 with micro channel */
  71   }
  72
  73   /* Type of VDU: */
  74   value = get_value(params_buffer, "video");    /* EGA or VGA video unit */
  75   if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
  76   if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
  77
  78   /* Get clock tick frequency. */
  79   value = get_value(params_buffer, "hz");
  80   if(value)
  81         system_hz = atoi(value);
  82   if(!value || system_hz < 2 || system_hz > 50000)      /* sanity check */
  83         system_hz = DEFAULT_HZ;
  84   value = get_value(params_buffer, SERVARNAME);
  85   if(value && atoi(value) == 0)
  86         do_serial_debug=1;
  87
  88 #ifdef CONFIG_APIC
  89   value = get_value(params_buffer, "no_apic");
  90   if(value)
  91         config_no_apic = atoi(value);
  92   else
  93         config_no_apic = 1;
  94 #endif
  95
  96 #ifdef CONFIG_WATCHDOG
  97   value = get_value(params_buffer, "watchdog");
  98   if (value)
  99           watchdog_enabled = atoi(value);
 100 #endif
 101
 102   /* Return to assembler code to switch to protected mode (if 286),
 103    * reload selectors and call main().
 104    */
 105
 106   DEBUGMAX(("intr_init(%d, 0)\n", INTS_MINIX));
 107   intr_init(INTS_MINIX, 0);
 108 }
 109
 110 /*===========================================================================*
 111  *                              get_value                                    *
 112  *===========================================================================*/
 113
 114 PRIVATE char *get_value(params, name)
 115 _CONST char *params;                            /* boot monitor parameters */
 116 _CONST char *name;                              /* key to look up */
 117 {
 118 /* Get environment value - kernel version of getenv to avoid setting up the
 119  * usual environment array.
 120  */
 121   register _CONST char *namep;
 122   register char *envp;
 123
 124   for (envp = (char *) params; *envp != 0;) {
 125         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
 126                 ;
 127         if (*namep == '\0' && *envp == '=') return(envp + 1);
 128         while (*envp++ != 0)
 129                 ;
 130   }
 131   return(NIL_PTR);
 132 }