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 <archconst.h>
   9 #include "proto.h"
  10
  11 FORWARD _PROTOTYPE( char *get_value, (_CONST char *params, _CONST char *key));
  12 /*===========================================================================*
  13  *                              cstart                                       *
  14  *===========================================================================*/
  15 PUBLIC void cstart(cs, ds, mds, parmoff, parmsize)
  16 U16_t cs, ds;                   /* kernel code and data segment */
  17 U16_t mds;                      /* monitor data segment */
  18 U16_t parmoff, parmsize;        /* boot parameters offset and length */
  19 {
  20 /* Perform system initializations prior to calling main(). Most settings are
  21  * determined with help of the environment strings passed by MINIX' loader.
  22  */
  23   register char *value;                         /* value in key=value pair */
  24   extern int etext, end;
  25   int h;
  26
  27   /* Record where the kernel and the monitor are. */
  28   kinfo.code_base = seg2phys(cs);
  29   kinfo.code_size = (phys_bytes) &etext;        /* size of code segment */
  30   kinfo.data_base = seg2phys(ds);
  31   kinfo.data_size = (phys_bytes) &end;          /* size of data segment */
  32
  33   /* protection initialization */
  34   prot_init();
  35
  36   /* Copy the boot parameters to the local buffer. */
  37   arch_get_params(params_buffer, sizeof(params_buffer));
  38
  39   /* Record miscellaneous information for user-space servers. */
  40   kinfo.nr_procs = NR_PROCS;
  41   kinfo.nr_tasks = NR_TASKS;
  42   strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
  43   kinfo.release[sizeof(kinfo.release)-1] = '\0';
  44   strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
  45   kinfo.version[sizeof(kinfo.version)-1] = '\0';
  46   kinfo.proc_addr = (vir_bytes) proc;
  47
  48   /* Load average data initialization. */
  49   kloadinfo.proc_last_slot = 0;
  50   for(h = 0; h < _LOAD_HISTORY; h++)
  51         kloadinfo.proc_load_history[h] = 0;
  52
  53   /* Processor? Decide if mode is protected for older machines. */
  54   machine.processor=atoi(get_value(params_buffer, "processor"));
  55
  56   /* XT, AT or MCA bus? */
  57   value = get_value(params_buffer, "bus");
  58   if (value == NIL_PTR || strcmp(value, "at") == 0) {
  59       machine.pc_at = TRUE;                     /* PC-AT compatible hardware */
  60   } else if (strcmp(value, "mca") == 0) {
  61       machine.pc_at = machine.ps_mca = TRUE;    /* PS/2 with micro channel */
  62   }
  63
  64   /* Type of VDU: */
  65   value = get_value(params_buffer, "video");    /* EGA or VGA video unit */
  66   if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
  67   if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
  68
  69   /* Get clock tick frequency. */
  70   value = get_value(params_buffer, "hz");
  71   if(value)
  72         system_hz = atoi(value);
  73   if(!value || system_hz < 2 || system_hz > 50000)      /* sanity check */
  74         system_hz = DEFAULT_HZ;
  75   value = get_value(params_buffer, SERVARNAME);
  76   if(value && atoi(value) == 0)
  77         do_serial_debug=1;
  78
  79 #ifdef CONFIG_APIC
  80   value = get_value(params_buffer, "no_apic");
  81   if(value)
  82         config_no_apic = atoi(value);
  83   else
  84         config_no_apic = 0;
  85 #endif
  86
  87   /* Return to assembler code to switch to protected mode (if 286),
  88    * reload selectors and call main().
  89    */
  90
  91   intr_init(INTS_MINIX, 0);
  92 }
  93
  94 /*===========================================================================*
  95  *                              get_value                                    *
  96  *===========================================================================*/
  97
  98 PRIVATE char *get_value(params, name)
  99 _CONST char *params;                            /* boot monitor parameters */
 100 _CONST char *name;                              /* key to look up */
 101 {
 102 /* Get environment value - kernel version of getenv to avoid setting up the
 103  * usual environment array.
 104  */
 105   register _CONST char *namep;
 106   register char *envp;
 107
 108   for (envp = (char *) params; *envp != 0;) {
 109         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
 110                 ;
 111         if (*namep == '\0' && *envp == '=') return(envp + 1);
 112         while (*envp++ != 0)
 113                 ;
 114   }
 115   return(NIL_PTR);
 116 }