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   /* Record miscellaneous information for user-space servers. */
  43   kinfo.nr_procs = NR_PROCS;
  44   kinfo.nr_tasks = NR_TASKS;
  45   strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
  46   kinfo.release[sizeof(kinfo.release)-1] = '\0';
  47   strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
  48   kinfo.version[sizeof(kinfo.version)-1] = '\0';
  49   kinfo.proc_addr = (vir_bytes) proc;
  50
  51   /* Load average data initialization. */
  52   kloadinfo.proc_last_slot = 0;
  53   for(h = 0; h < _LOAD_HISTORY; h++)
  54         kloadinfo.proc_load_history[h] = 0;
  55
  56   /* Processor? Decide if mode is protected for older machines. */
  57   machine.processor=atoi(get_value(params_buffer, "processor"));
  58
  59   /* XT, AT or MCA bus? */
  60   value = get_value(params_buffer, "bus");
  61   if (value == NIL_PTR || strcmp(value, "at") == 0) {
  62       machine.pc_at = TRUE;                     /* PC-AT compatible hardware */
  63   } else if (strcmp(value, "mca") == 0) {
  64       machine.pc_at = machine.ps_mca = TRUE;    /* PS/2 with micro channel */
  65   }
  66
  67   /* Type of VDU: */
  68   value = get_value(params_buffer, "video");    /* EGA or VGA video unit */
  69   if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
  70   if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
  71
  72   /* Get clock tick frequency. */
  73   value = get_value(params_buffer, "hz");
  74   if(value)
  75         system_hz = atoi(value);
  76   if(!value || system_hz < 2 || system_hz > 50000)      /* sanity check */
  77         system_hz = DEFAULT_HZ;
  78   value = get_value(params_buffer, SERVARNAME);
  79   if(value && atoi(value) == 0)
  80         do_serial_debug=1;
  81
  82 #ifdef CONFIG_APIC
  83   value = get_value(params_buffer, "no_apic");
  84   if(value)
  85         config_no_apic = atoi(value);
  86   else
  87         config_no_apic = 1;
  88 #endif
  89
  90 #ifdef CONFIG_WATCHDOG
  91   value = get_value(params_buffer, "watchdog");
  92   if (value)
  93           watchdog_enabled = atoi(value);
  94 #endif
  95
  96   /* Return to assembler code to switch to protected mode (if 286),
  97    * reload selectors and call main().
  98    */
  99
 100   intr_init(INTS_MINIX, 0);
 101 }
 102
 103 /*===========================================================================*
 104  *                              get_value                                    *
 105  *===========================================================================*/
 106
 107 PRIVATE char *get_value(params, name)
 108 _CONST char *params;                            /* boot monitor parameters */
 109 _CONST char *name;                              /* key to look up */
 110 {
 111 /* Get environment value - kernel version of getenv to avoid setting up the
 112  * usual environment array.
 113  */
 114   register _CONST char *namep;
 115   register char *envp;
 116
 117   for (envp = (char *) params; *envp != 0;) {
 118         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
 119                 ;
 120         if (*namep == '\0' && *envp == '=') return(envp + 1);
 121         while (*envp++ != 0)
 122                 ;
 123   }
 124   return(NIL_PTR);
 125 }