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
  10 PRIVATE char params[K_PARAM_SIZE];
  11
  12 FORWARD _PROTOTYPE( char *get_value, (_CONST char *params, _CONST char *key));
  13 /*===========================================================================*
  14  *                              cstart                                       *
  15  *===========================================================================*/
  16 PUBLIC void cstart(cs, ds, mds, parmoff, parmsize)
  17 U16_t cs, ds;                   /* kernel code and data segment */
  18 U16_t mds;                      /* monitor data segment */
  19 U16_t parmoff, parmsize;        /* boot parameters offset and length */
  20 {
  21 /* Perform system initializations prior to calling main(). Most settings are
  22  * determined with help of the environment strings passed by MINIX' loader.
  23  */
  24   char params[128*sizeof(char *)];              /* boot monitor parameters */
  25   register char *value;                         /* value in key=value pair */
  26   extern int etext, end;
  27   int h;
  28
  29   /* Record where the kernel and the monitor are. */
  30   kinfo.code_base = seg2phys(cs);
  31   kinfo.code_size = (phys_bytes) &etext;        /* size of code segment */
  32   kinfo.data_base = seg2phys(ds);
  33   kinfo.data_size = (phys_bytes) &end;          /* size of data segment */
  34
  35   /* Architecture-dependent initialization. */
  36   system_init();
  37
  38   /* Copy the boot parameters to the local buffer. */
  39   kinfo.params_base = seg2phys(mds) + parmoff;
  40   kinfo.params_size = MIN(parmsize,sizeof(params)-2);
  41   phys_copy(kinfo.params_base,
  42         vir2phys(params), kinfo.params_size);
  43
  44   /* Record miscellaneous information for user-space servers. */
  45   kinfo.nr_procs = NR_PROCS;
  46   kinfo.nr_tasks = NR_TASKS;
  47   strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
  48   kinfo.release[sizeof(kinfo.release)-1] = '\0';
  49   strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
  50   kinfo.version[sizeof(kinfo.version)-1] = '\0';
  51   kinfo.proc_addr = (vir_bytes) proc;
  52   kinfo.kmem_base = vir2phys(0);
  53   kinfo.kmem_size = (phys_bytes) &end;
  54
  55   /* Load average data initialization. */
  56   kloadinfo.proc_last_slot = 0;
  57   for(h = 0; h < _LOAD_HISTORY; h++)
  58         kloadinfo.proc_load_history[h] = 0;
  59
  60   /* Processor? Decide if mode is protected for older machines. */
  61   machine.processor=atoi(get_value(params, "processor"));
  62
  63   /* XT, AT or MCA bus? */
  64   value = get_value(params, "bus");
  65   if (value == NIL_PTR || strcmp(value, "at") == 0) {
  66       machine.pc_at = TRUE;                     /* PC-AT compatible hardware */
  67   } else if (strcmp(value, "mca") == 0) {
  68       machine.pc_at = machine.ps_mca = TRUE;    /* PS/2 with micro channel */
  69   }
  70
  71   /* Type of VDU: */
  72   value = get_value(params, "video");           /* EGA or VGA video unit */
  73   if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
  74   if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
  75
  76   /* Return to assembler code to switch to protected mode (if 286),
  77    * reload selectors and call main().
  78    */
  79
  80   intr_init(INTS_MINIX);
  81 }
  82
  83 /*===========================================================================*
  84  *                              get_value                                    *
  85  *===========================================================================*/
  86
  87 PRIVATE char *get_value(params, name)
  88 _CONST char *params;                            /* boot monitor parameters */
  89 _CONST char *name;                              /* key to look up */
  90 {
  91 /* Get environment value - kernel version of getenv to avoid setting up the
  92  * usual environment array.
  93  */
  94   register _CONST char *namep;
  95   register char *envp;
  96
  97   for (envp = (char *) params; *envp != 0;) {
  98         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
  99                 ;
 100         if (*namep == '\0' && *envp == '=') return(envp + 1);
 101         while (*envp++ != 0)
 102                 ;
 103   }
 104   return(NIL_PTR);
 105 }