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Annotation of Gnu-Mach/i386/dos/i16/i16_dos_mem.c, revision 1.1

1.1     ! root        1: /* 
        !             2:  * Copyright (c) 1995-1994 The University of Utah and
        !             3:  * the Computer Systems Laboratory at the University of Utah (CSL).
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * Permission to use, copy, modify and distribute this software is hereby
        !             7:  * granted provided that (1) source code retains these copyright, permission,
        !             8:  * and disclaimer notices, and (2) redistributions including binaries
        !             9:  * reproduce the notices in supporting documentation, and (3) all advertising
        !            10:  * materials mentioning features or use of this software display the following
        !            11:  * acknowledgement: ``This product includes software developed by the
        !            12:  * Computer Systems Laboratory at the University of Utah.''
        !            13:  *
        !            14:  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
        !            15:  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
        !            16:  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            17:  *
        !            18:  * CSL requests users of this software to return to [email protected] any
        !            19:  * improvements that they make and grant CSL redistribution rights.
        !            20:  *
        !            21:  *      Author: Bryan Ford, University of Utah CSL
        !            22:  */
        !            23: 
        !            24: #include <mach/machine/code16.h>
        !            25: #include <mach/machine/vm_types.h>
        !            26: 
        !            27: #include "i16_dos.h"
        !            28: #include "config.h"
        !            29: 
        !            30: 
        !            31: 
        !            32: /* These aren't static because vcpi and dpmi code need to grab DOS memory
        !            33:    before we've switched to protected mode and memory has been collected.  */
        !            34: vm_offset_t dos_mem_phys_free_mem;
        !            35: vm_size_t dos_mem_phys_free_size;
        !            36: 
        !            37: 
        !            38: CODE32
        !            39: 
        !            40: void dos_mem_collect(void)
        !            41: {
        !            42:        if (dos_mem_phys_free_mem)
        !            43:        {
        !            44:                phys_mem_add(dos_mem_phys_free_mem, dos_mem_phys_free_size);
        !            45:                dos_mem_phys_free_mem = 0;
        !            46:        }
        !            47: }
        !            48: 
        !            49: CODE16
        !            50: 
        !            51: void i16_dos_mem_check()
        !            52: {
        !            53:        unsigned short paras = 0xf000;
        !            54:        int dos_mem_seg;
        !            55: 
        !            56:        /* Allocate as big a chunk of memory as we can find.  */
        !            57:        do
        !            58:        {
        !            59:                if (paras == 0)
        !            60:                        return;
        !            61:                dos_mem_seg = i16_dos_alloc(&paras);
        !            62:        }
        !            63:        while (dos_mem_seg < 0);
        !            64: 
        !            65:        dos_mem_phys_free_mem = dos_mem_seg << 4;
        !            66:        dos_mem_phys_free_size = paras << 4;
        !            67: 
        !            68: #ifdef ENABLE_CODE_CHECK
        !            69:        i16_code_copy();
        !            70: #endif
        !            71: }
        !            72: 
        !            73: 
        !            74: #ifdef ENABLE_CODE_CHECK
        !            75: 
        !            76: /* Big humongo kludge to help in finding random code-trashing bugs.
        !            77:    We copy the entire text segment upon initialization,
        !            78:    and then check it later as necessary.  */
        !            79: 
        !            80: #include <mach/machine/proc_reg.h>
        !            81: #include "vm_param.h"
        !            82: 
        !            83: extern char etext[], i16_entry_2[];
        !            84: 
        !            85: static int code_copy_seg;
        !            86: 
        !            87: static int i16_code_copy()
        !            88: {
        !            89:        int text_size = (int)etext & ~0xf;
        !            90:        int i;
        !            91: 
        !            92:        if (dos_mem_phys_free_size < text_size)
        !            93:                return;
        !            94: 
        !            95:        code_copy_seg = dos_mem_phys_free_mem >> 4;
        !            96:        dos_mem_phys_free_mem += text_size;
        !            97:        dos_mem_phys_free_size -= text_size;
        !            98: 
        !            99:        set_fs(code_copy_seg);
        !           100:        for (i = 0; i < text_size; i += 4)
        !           101:                asm volatile("
        !           102:                        movl (%%ebx),%%eax
        !           103:                        movl %%eax,%%fs:(%%ebx)
        !           104:                " : : "b" (i) : "eax");
        !           105: }
        !           106: 
        !           107: void i16_code_check(int dummy)
        !           108: {
        !           109:        int text_size = (int)etext & ~0xf;
        !           110:        int i, old, new;
        !           111:        int found = 0;
        !           112: 
        !           113:        if (!code_copy_seg)
        !           114:                return;
        !           115: 
        !           116:        set_fs(code_copy_seg);
        !           117:        for (i = (int)i16_entry_2; i < text_size; i += 4)
        !           118:        {
        !           119:                asm volatile("
        !           120:                        movl (%%ebx),%%eax
        !           121:                        movl %%fs:(%%ebx),%%ecx
        !           122:                " : "=a" (new), "=c" (old) : "b" (i));
        !           123:                if (old != new)
        !           124:                {
        !           125:                        found = 1;
        !           126:                        i16_writehexw(i);
        !           127:                        i16_putchar(' ');
        !           128:                        i16_writehexl(old);
        !           129:                        i16_putchar(' ');
        !           130:                        i16_writehexl(new);
        !           131:                        i16_putchar('\r');
        !           132:                        i16_putchar('\n');
        !           133:                }
        !           134:        }
        !           135:        if (found)
        !           136:        {
        !           137:                code_copy_seg = 0;
        !           138:                i16_writehexl((&dummy)[-1]);
        !           139:                i16_die(" DOS extender code trashed!");
        !           140:        }
        !           141: }
        !           142: 
        !           143: CODE32
        !           144: 
        !           145: void code_check(int dummy)
        !           146: {
        !           147:        int text_size = (int)etext & ~0xf;
        !           148:        unsigned char *new = 0, *old = (void*)phystokv(code_copy_seg*16);
        !           149:        int found = 0;
        !           150:        int i;
        !           151: 
        !           152:        if (!code_copy_seg)
        !           153:                return;
        !           154: 
        !           155:        for (i = (int)i16_entry_2; (i < text_size) && (found < 10); i++)
        !           156:        {
        !           157:                /* In several places we have to self-modify an int instruction,
        !           158:                   or the segment value in an absolute long jmp instruction,
        !           159:                   so ignore any changes preceded by those opcodes.  */
        !           160:                if ((new[i] != old[i])
        !           161:                    && (old[i-1] != 0xcd)
        !           162:                    && (old[i-6] != 0xea))
        !           163:                {
        !           164:                        if (!found)
        !           165:                        {
        !           166:                                found = 1;
        !           167:                                about_to_die(1);
        !           168:                        }
        !           169:                        printf("%08x addr %04x was %02x now %02x\n",
        !           170:                                (&dummy)[-1], i, old[i], new[i]);
        !           171:                }
        !           172:        }
        !           173:        if (found)
        !           174:        {
        !           175:                code_copy_seg = 0;
        !           176:                die("%08x DOS extender code trashed!", (&dummy)[-1]);
        !           177:        }
        !           178: }
        !           179: 
        !           180: CODE16
        !           181: 
        !           182: #endif ENABLE_CODE_CHECK

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