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/* $Id: bs3-cmn-TrapRmV86Init.c $ */
/** @file
* BS3Kit - Bs3TrapRmV86Init
*/
/*
* Copyright (C) 2007-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include "bs3kit-template-header.h"
/*********************************************************************************************************************************
* Global Variables *
*********************************************************************************************************************************/
/* We ASSUME that BS3CLASS16CODE is 64KB aligned, so the low 16-bit of the
flat address matches. Also, these symbols are defined both with
and without underscore prefixes. */
extern BS3_DECL(void) BS3_FAR_CODE Bs3TrapRmV86GenericEntries(void);
/* These two are ugly. Need data access for patching purposes. */
extern uint8_t BS3_FAR_DATA bs3TrapRmV86GenericTrapOrInt[];
/* bs3-cmn-TrapRmV86Data.c: */
#define g_fBs3RmIvtCopied BS3_DATA_NM(g_fBs3RmIvtCopied)
extern bool g_fBs3RmIvtCopied;
#undef Bs3TrapRmV86InitEx
BS3_CMN_DEF(void, Bs3TrapRmV86InitEx,(bool f386Plus))
{
RTFAR16 BS3_FAR *paIvt = Bs3XptrFlatToCurrent(0);
unsigned iIvt;
/*
* Copy the real mode IVT the first time we are here.
*/
if (!g_fBs3RmIvtCopied)
{
Bs3MemCpy(g_aBs3RmIvtOriginal, paIvt, sizeof(g_aBs3RmIvtOriginal));
g_fBs3RmIvtCopied = true;
}
/*
* The rest of the times, we copy back the original and modify it.
*/
else
Bs3MemCpy(paIvt, g_aBs3RmIvtOriginal, sizeof(g_aBs3RmIvtOriginal));
/*
* If 386 or later, patch the trap handler code to not jump to the 80286
* code but continue with the next instruction (the 386+ code).
*/
if (f386Plus)
{
uint8_t BS3_FAR_DATA *pbFunction = &bs3TrapRmV86GenericTrapOrInt[0];
#if ARCH_BITS == 16
if (g_bBs3CurrentMode != BS3_MODE_RM)
pbFunction = (uint8_t BS3_FAR_DATA *)BS3_FP_MAKE(BS3_SEL_TILED + 1, BS3_FP_OFF(pbFunction));
#endif
pbFunction[1] = 0;
pbFunction[2] = 0;
}
/*
* Since we want to play with V86 mode as well as 8086 and 186 CPUs, we
* cannot move the IVT from its default location. So, modify it in place.
*
* Note! We must keep INT 10h working, which is easy since the CPU does
* use it (well, it's been reserved for 30+ years).
* Turns out we must not hook INT 6Dh either then, as some real VGA
* BIOS installs their INT 10h handler there as well, and seemingly
* must be using it internally or something.
*/
for (iIvt = 0; iIvt < 256; iIvt++)
if (iIvt != 0x10 && iIvt != 0x6d && iIvt != BS3_TRAP_SYSCALL)
{
paIvt[iIvt].off = (uint16_t)(uintptr_t)Bs3TrapRmV86GenericEntries + iIvt * 8;
paIvt[iIvt].sel = BS3_SEL_TEXT16;
}
}
#undef Bs3TrapRmV86Init
BS3_CMN_DEF(void, Bs3TrapRmV86Init,(void))
{
BS3_CMN_NM(Bs3TrapRmV86InitEx)((g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80386);
}
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