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/* $Id: bs3-cmn-TrapRmV86Init.c $ */
/** @file
* BS3Kit - Bs3TrapRmV86Init
*/
/*
* Copyright (C) 2007-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox 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.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* 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.
*
* We also keep 15h working for memory interfaces (see bs3-mode-BiosInt15*).
*/
for (iIvt = 0; iIvt < 256; iIvt++)
if (iIvt != 0x10 && iIvt != 0x15 && 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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