| 1 | /* This file contains the C startup code for Minix on Intel processors.
|
|---|
| 2 | * It cooperates with mpx.s to set up a good environment for main().
|
|---|
| 3 | *
|
|---|
| 4 | * This code runs in real mode for a 16 bit kernel and may have to switch
|
|---|
| 5 | * to protected mode for a 286.
|
|---|
| 6 | * For a 32 bit kernel this already runs in protected mode, but the selectors
|
|---|
| 7 | * are still those given by the BIOS with interrupts disabled, so the
|
|---|
| 8 | * descriptors need to be reloaded and interrupt descriptors made.
|
|---|
| 9 | */
|
|---|
| 10 |
|
|---|
| 11 | #include "kernel.h"
|
|---|
| 12 | #include "protect.h"
|
|---|
| 13 | #include "proc.h"
|
|---|
| 14 | #include <stdlib.h>
|
|---|
| 15 | #include <string.h>
|
|---|
| 16 |
|
|---|
| 17 | FORWARD _PROTOTYPE( char *get_value, (_CONST char *params, _CONST char *key));
|
|---|
| 18 | /*===========================================================================*
|
|---|
| 19 | * cstart *
|
|---|
| 20 | *===========================================================================*/
|
|---|
| 21 | PUBLIC void cstart(cs, ds, mds, parmoff, parmsize)
|
|---|
| 22 | U16_t cs, ds; /* kernel code and data segment */
|
|---|
| 23 | U16_t mds; /* monitor data segment */
|
|---|
| 24 | U16_t parmoff, parmsize; /* boot parameters offset and length */
|
|---|
| 25 | {
|
|---|
| 26 | /* Perform system initializations prior to calling main(). Most settings are
|
|---|
| 27 | * determined with help of the environment strings passed by MINIX' loader.
|
|---|
| 28 | */
|
|---|
| 29 | char params[128*sizeof(char *)]; /* boot monitor parameters */
|
|---|
| 30 | register char *value; /* value in key=value pair */
|
|---|
| 31 | extern int etext, end;
|
|---|
| 32 |
|
|---|
| 33 | /* Decide if mode is protected; 386 or higher implies protected mode.
|
|---|
| 34 | * This must be done first, because it is needed for, e.g., seg2phys().
|
|---|
| 35 | * For 286 machines we cannot decide on protected mode, yet. This is
|
|---|
| 36 | * done below.
|
|---|
| 37 | */
|
|---|
| 38 | #if _WORD_SIZE != 2
|
|---|
| 39 | machine.protected = 1;
|
|---|
| 40 | #endif
|
|---|
| 41 |
|
|---|
| 42 | /* Record where the kernel and the monitor are. */
|
|---|
| 43 | kinfo.code_base = seg2phys(cs);
|
|---|
| 44 | kinfo.code_size = (phys_bytes) &etext; /* size of code segment */
|
|---|
| 45 | kinfo.data_base = seg2phys(ds);
|
|---|
| 46 | kinfo.data_size = (phys_bytes) &end; /* size of data segment */
|
|---|
| 47 |
|
|---|
| 48 | /* Initialize protected mode descriptors. */
|
|---|
| 49 | prot_init();
|
|---|
| 50 |
|
|---|
| 51 | /* Copy the boot parameters to the local buffer. */
|
|---|
| 52 | kinfo.params_base = seg2phys(mds) + parmoff;
|
|---|
| 53 | kinfo.params_size = MIN(parmsize,sizeof(params)-2);
|
|---|
| 54 | phys_copy(kinfo.params_base, vir2phys(params), kinfo.params_size);
|
|---|
| 55 |
|
|---|
| 56 | /* Record miscellaneous information for user-space servers. */
|
|---|
| 57 | kinfo.nr_procs = NR_PROCS;
|
|---|
| 58 | kinfo.nr_tasks = NR_TASKS;
|
|---|
| 59 | strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
|
|---|
| 60 | kinfo.release[sizeof(kinfo.release)-1] = '\0';
|
|---|
| 61 | strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
|
|---|
| 62 | kinfo.version[sizeof(kinfo.version)-1] = '\0';
|
|---|
| 63 | kinfo.proc_addr = (vir_bytes) proc;
|
|---|
| 64 | kinfo.kmem_base = vir2phys(0);
|
|---|
| 65 | kinfo.kmem_size = (phys_bytes) &end;
|
|---|
| 66 |
|
|---|
| 67 | /* Processor? 86, 186, 286, 386, ...
|
|---|
| 68 | * Decide if mode is protected for older machines.
|
|---|
| 69 | */
|
|---|
| 70 | machine.processor=atoi(get_value(params, "processor"));
|
|---|
| 71 | #if _WORD_SIZE == 2
|
|---|
| 72 | machine.protected = machine.processor >= 286;
|
|---|
| 73 | #endif
|
|---|
| 74 | if (! machine.protected) mon_return = 0;
|
|---|
| 75 |
|
|---|
| 76 | /* XT, AT or MCA bus? */
|
|---|
| 77 | value = get_value(params, "bus");
|
|---|
| 78 | if (value == NIL_PTR || strcmp(value, "at") == 0) {
|
|---|
| 79 | machine.pc_at = TRUE; /* PC-AT compatible hardware */
|
|---|
| 80 | } else if (strcmp(value, "mca") == 0) {
|
|---|
| 81 | machine.pc_at = machine.ps_mca = TRUE; /* PS/2 with micro channel */
|
|---|
| 82 | }
|
|---|
| 83 |
|
|---|
| 84 | /* Type of VDU: */
|
|---|
| 85 | value = get_value(params, "video"); /* EGA or VGA video unit */
|
|---|
| 86 | if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
|
|---|
| 87 | if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
|
|---|
| 88 |
|
|---|
| 89 | /* Return to assembler code to switch to protected mode (if 286),
|
|---|
| 90 | * reload selectors and call main().
|
|---|
| 91 | */
|
|---|
| 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 | }
|
|---|
