| 1 | /* This file contains the C startup code for Minix on Intel processors.
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| 2 | * It cooperates with mpx.s to set up a good environment for main().
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| 3 | *
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| 4 | * This code runs in real mode for a 16 bit kernel and may have to switch
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| 5 | * to protected mode for a 286.
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| 6 | * For a 32 bit kernel this already runs in protected mode, but the selectors
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| 7 | * are still those given by the BIOS with interrupts disabled, so the
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| 8 | * descriptors need to be reloaded and interrupt descriptors made.
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| 9 | */
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| 10 |
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| 11 | #include "kernel.h"
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| 12 | #include "protect.h"
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| 13 | #include "proc.h"
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| 14 | #include <stdlib.h>
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| 15 | #include <string.h>
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| 16 |
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| 17 | FORWARD _PROTOTYPE( char *get_value, (_CONST char *params, _CONST char *key));
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| 18 | /*===========================================================================*
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| 19 | * cstart *
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| 20 | *===========================================================================*/
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| 21 | PUBLIC void cstart(cs, ds, mds, parmoff, parmsize)
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| 22 | U16_t cs, ds; /* kernel code and data segment */
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| 23 | U16_t mds; /* monitor data segment */
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| 24 | U16_t parmoff, parmsize; /* boot parameters offset and length */
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| 25 | {
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| 26 | /* Perform system initializations prior to calling main(). Most settings are
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| 27 | * determined with help of the environment strings passed by MINIX' loader.
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| 28 | */
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| 29 | char params[128*sizeof(char *)]; /* boot monitor parameters */
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| 30 | register char *value; /* value in key=value pair */
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| 31 | extern int etext, end;
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| 32 | int h;
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| 33 |
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| 34 | /* Decide if mode is protected; 386 or higher implies protected mode.
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| 35 | * This must be done first, because it is needed for, e.g., seg2phys().
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| 36 | * For 286 machines we cannot decide on protected mode, yet. This is
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| 37 | * done below.
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| 38 | */
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| 39 | #if _WORD_SIZE != 2
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| 40 | machine.prot = 1;
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| 41 | #endif
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| 42 |
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| 43 | /* Record where the kernel and the monitor are. */
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| 44 | kinfo.code_base = seg2phys(cs);
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| 45 | kinfo.code_size = (phys_bytes) &etext; /* size of code segment */
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| 46 | kinfo.data_base = seg2phys(ds);
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| 47 | kinfo.data_size = (phys_bytes) &end; /* size of data segment */
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| 48 |
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| 49 | /* Initialize protected mode descriptors. */
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| 50 | prot_init();
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| 51 |
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| 52 | /* Copy the boot parameters to the local buffer. */
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| 53 | kinfo.params_base = seg2phys(mds) + parmoff;
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| 54 | kinfo.params_size = MIN(parmsize,sizeof(params)-2);
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| 55 | phys_copy(kinfo.params_base, vir2phys(params), kinfo.params_size);
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| 56 |
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| 57 | /* Record miscellaneous information for user-space servers. */
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| 58 | kinfo.nr_procs = NR_PROCS;
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| 59 | kinfo.nr_tasks = NR_TASKS;
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| 60 | strncpy(kinfo.release, OS_RELEASE, sizeof(kinfo.release));
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| 61 | kinfo.release[sizeof(kinfo.release)-1] = '\0';
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| 62 | strncpy(kinfo.version, OS_VERSION, sizeof(kinfo.version));
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| 63 | kinfo.version[sizeof(kinfo.version)-1] = '\0';
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| 64 | kinfo.proc_addr = (vir_bytes) proc;
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| 65 | kinfo.kmem_base = vir2phys(0);
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| 66 | kinfo.kmem_size = (phys_bytes) &end;
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| 67 |
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| 68 | /* Load average data initialization. */
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| 69 | kloadinfo.proc_last_slot = 0;
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| 70 | for(h = 0; h < _LOAD_HISTORY; h++)
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| 71 | kloadinfo.proc_load_history[h] = 0;
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| 72 |
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| 73 | /* Processor? 86, 186, 286, 386, ...
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| 74 | * Decide if mode is protected for older machines.
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| 75 | */
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| 76 | machine.processor=atoi(get_value(params, "processor"));
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| 77 | #if _WORD_SIZE == 2
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| 78 | machine.prot = machine.processor >= 286;
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| 79 | #endif
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| 80 | if (! machine.prot) mon_return = 0;
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| 81 |
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| 82 | /* XT, AT or MCA bus? */
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| 83 | value = get_value(params, "bus");
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| 84 | if (value == NIL_PTR || strcmp(value, "at") == 0) {
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| 85 | machine.pc_at = TRUE; /* PC-AT compatible hardware */
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| 86 | } else if (strcmp(value, "mca") == 0) {
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| 87 | machine.pc_at = machine.ps_mca = TRUE; /* PS/2 with micro channel */
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| 88 | }
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| 89 |
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| 90 | /* Type of VDU: */
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| 91 | value = get_value(params, "video"); /* EGA or VGA video unit */
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| 92 | if (strcmp(value, "ega") == 0) machine.vdu_ega = TRUE;
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| 93 | if (strcmp(value, "vga") == 0) machine.vdu_vga = machine.vdu_ega = TRUE;
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| 94 |
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| 95 | /* Return to assembler code to switch to protected mode (if 286),
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| 96 | * reload selectors and call main().
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| 97 | */
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| 98 | }
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| 99 |
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| 100 | /*===========================================================================*
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| 101 | * get_value *
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| 102 | *===========================================================================*/
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| 103 |
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| 104 | PRIVATE char *get_value(params, name)
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| 105 | _CONST char *params; /* boot monitor parameters */
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| 106 | _CONST char *name; /* key to look up */
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| 107 | {
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| 108 | /* Get environment value - kernel version of getenv to avoid setting up the
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| 109 | * usual environment array.
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| 110 | */
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| 111 | register _CONST char *namep;
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| 112 | register char *envp;
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| 113 |
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| 114 | for (envp = (char *) params; *envp != 0;) {
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| 115 | for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
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| 116 | ;
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| 117 | if (*namep == '\0' && *envp == '=') return(envp + 1);
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| 118 | while (*envp++ != 0)
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| 119 | ;
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| 120 | }
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| 121 | return(NIL_PTR);
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| 122 | }
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