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a0147fe055
Bochs/bochs/cpu/exception.cc
Stanislav Shwartsman a0147fe055 Fixed bug prevented to boot Win98
2007-11-30 08:49:12 +00:00

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/////////////////////////////////////////////////////////////////////////
// $Id: exception.cc,v 1.97 2007-11-30 08:49:12 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
//
// MandrakeSoft S.A.
// 43, rue d'Aboukir
// 75002 Paris - France
// http://www.linux-mandrake.com/
// http://www.mandrakesoft.com/
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
#include "iodev/iodev.h"
#if BX_SUPPORT_X86_64==0
// Make life easier merging cpu64 & cpu code.
#define RIP EIP
#define RSP ESP
#endif
/* Exception classes. These are used as indexes into the 'is_exception_OK'
* array below, and are stored in the 'exception' array also
*/
#define BX_ET_BENIGN 0
#define BX_ET_CONTRIBUTORY 1
#define BX_ET_PAGE_FAULT 2
#define BX_ET_DOUBLE_FAULT 10
static const bx_bool is_exception_OK[3][3] = {
{ 1, 1, 1 }, /* 1st exception is BENIGN */
{ 1, 0, 1 }, /* 1st exception is CONTRIBUTORY */
{ 1, 0, 0 } /* 1st exception is PAGE_FAULT */
};
#define BX_EXCEPTION_CLASS_TRAP 0
#define BX_EXCEPTION_CLASS_FAULT 1
#define BX_EXCEPTION_CLASS_ABORT 2
#if BX_SUPPORT_X86_64
void BX_CPU_C::long_mode_int(Bit8u vector, bx_bool is_INT, bx_bool is_error_code, Bit16u error_code)
{
// long mode interrupt
Bit64u idtindex;
Bit32u dword1, dword2, dword3;
bx_descriptor_t gate_descriptor, cs_descriptor;
bx_selector_t cs_selector;
// interrupt vector must be within IDT table limits,
// else #GP(vector number*16 + 2 + EXT)
idtindex = vector*16;
if ( (idtindex + 15) > BX_CPU_THIS_PTR idtr.limit) {
BX_ERROR(("interrupt(long mode): vector > idtr.limit"));
BX_ERROR(("IDT.limit = %04x", (unsigned) BX_CPU_THIS_PTR idtr.limit));
BX_ERROR(("IDT.base = %06x", (unsigned) BX_CPU_THIS_PTR idtr.base));
BX_ERROR(("interrupt vector must be within IDT table limits"));
exception(BX_GP_EXCEPTION, vector*16 + 2, 0);
}
// descriptor AR byte must indicate interrupt gate, trap gate,
// or task gate, else #GP(vector*16 + 2 + EXT)
idtindex += BX_CPU_THIS_PTR idtr.base;
access_linear(idtindex, 4, 0, BX_READ, &dword1);
access_linear(idtindex + 4, 4, 0, BX_READ, &dword2);
access_linear(idtindex + 8, 4, 0, BX_READ, &dword3);
parse_descriptor(dword1, dword2, &gate_descriptor);
if ((gate_descriptor.valid==0) || gate_descriptor.segment)
{
BX_ERROR(("interrupt(long mode): gate descriptor is not valid sys seg"));
exception(BX_GP_EXCEPTION, vector*16 + 2, 0);
}
if (gate_descriptor.type != BX_386_INTERRUPT_GATE &&
gate_descriptor.type != BX_386_TRAP_GATE)
{
BX_ERROR(("interrupt(long mode): unsupported gate type %u",
(unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, vector*16 + 2, 0);
}
// if software interrupt, then gate descripor DPL must be >= CPL,
// else #GP(vector * 16 + 2 + EXT)
if (is_INT && (gate_descriptor.dpl < CPL))
{
BX_ERROR(("interrupt(long mode): is_INT && (dpl < CPL)"));
exception(BX_GP_EXCEPTION, vector*16 + 2, 0);
}
// Gate must be present, else #NP(vector * 16 + 2 + EXT)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("interrupt(long mode): p == 0"));
exception(BX_NP_EXCEPTION, vector*16 + 2, 0);
}
Bit16u gate_dest_selector = gate_descriptor.u.gate.dest_selector;
Bit64u gate_dest_offset = ((Bit64u)dword3 << 32) |
gate_descriptor.u.gate.dest_offset;
unsigned ist = gate_descriptor.u.gate.param_count & 0x7;
// examine CS selector and descriptor given in gate descriptor
// selector must be non-null else #GP(EXT)
if ((gate_dest_selector & 0xfffc) == 0) {
BX_ERROR(("int_trap_gate(long mode): selector null"));
exception(BX_GP_EXCEPTION, 0, 0);
}
parse_selector(gate_dest_selector, &cs_selector);
// selector must be within its descriptor table limits
// else #GP(selector+EXT)
fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &cs_descriptor);
// descriptor AR byte must indicate code seg
// and code segment descriptor DPL<=CPL, else #GP(selector+EXT)
if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
IS_DATA_SEGMENT(cs_descriptor.type) ||
cs_descriptor.dpl>CPL)
{
BX_ERROR(("interrupt(long mode): not accessable or not code segment"));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// check that it's a 64 bit segment
if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
{
BX_ERROR(("interrupt(long mode): must be 64 bit segment"));
exception(BX_GP_EXCEPTION, vector, 0);
}
// segment must be present, else #NP(selector + EXT)
if (! IS_PRESENT(cs_descriptor)) {
BX_ERROR(("interrupt(long mode): segment not present"));
exception(BX_NP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// if code segment is non-conforming and DPL < CPL then
// INTERRUPT TO INNER PRIVILEGE:
if ((IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type)
&& cs_descriptor.dpl<CPL) || (ist != 0))
{
Bit64u RSP_for_cpl_x;
BX_DEBUG(("interrupt(long mode): INTERRUPT TO INNER PRIVILEGE"));
// check selector and descriptor for new stack in current TSS
if (ist != 0) {
BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d\n",ist));
get_RSP_from_TSS(ist+3, &RSP_for_cpl_x);
}
else {
get_RSP_from_TSS(cs_descriptor.dpl, &RSP_for_cpl_x);
}
RSP_for_cpl_x &= BX_CONST64(0xfffffffffffffff0);
if (! IsCanonical(RSP_for_cpl_x)) {
BX_ERROR(("interrupt(long mode): canonical address failure %08x%08x",
GET32H(RSP_for_cpl_x), GET32L(RSP_for_cpl_x)));
exception(BX_GP_EXCEPTION, 0, 0);
}
Bit64u old_CS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
Bit64u old_RIP = RIP;
Bit64u old_SS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
Bit64u old_RSP = RSP;
bx_bool user = (cs_descriptor.dpl == 3);
// push old stack long pointer onto new stack
write_new_stack_qword(RSP_for_cpl_x - 8, user, old_SS);
write_new_stack_qword(RSP_for_cpl_x - 16, user, old_RSP);
write_new_stack_qword(RSP_for_cpl_x - 24, user, read_eflags());
// push long pointer to return address onto new stack
write_new_stack_qword(RSP_for_cpl_x - 32, user, old_CS);
write_new_stack_qword(RSP_for_cpl_x - 40, user, old_RIP);
RSP_for_cpl_x -= 40;
if (is_error_code) {
RSP_for_cpl_x -= 8;
write_new_stack_qword(RSP_for_cpl_x, user, error_code);
}
bx_selector_t ss_selector;
bx_descriptor_t ss_descriptor;
// set up a null descriptor
parse_selector(0, &ss_selector);
parse_descriptor(0, 0, &ss_descriptor);
// load CS:RIP (guaranteed to be in 64 bit mode)
branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, cs_descriptor.dpl);
// set up null SS descriptor
load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);
RSP = RSP_for_cpl_x;
// if INTERRUPT GATE set IF to 0
if (!(gate_descriptor.type & 1)) // even is int-gate
BX_CPU_THIS_PTR clear_IF();
BX_CPU_THIS_PTR clear_TF();
BX_CPU_THIS_PTR clear_VM();
BX_CPU_THIS_PTR clear_RF();
BX_CPU_THIS_PTR clear_NT();
return;
}
// if code segment is conforming OR code segment DPL = CPL then
// INTERRUPT TO SAME PRIVILEGE LEVEL:
if (IS_CODE_SEGMENT_CONFORMING(cs_descriptor.type) || cs_descriptor.dpl==CPL)
{
BX_DEBUG(("interrupt(long mode): INTERRUPT TO SAME PRIVILEGE"));
Bit64u old_RSP = RSP;
// check selector and descriptor for new stack in current TSS
if (ist > 0) {
BX_DEBUG(("interrupt(long mode): trap to IST, vector = %d\n",ist));
get_RSP_from_TSS(ist+3, &RSP);
}
// align stack
RSP &= BX_CONST64(0xfffffffffffffff0);
// push flags onto stack
// push current CS selector onto stack
// push return offset onto stack
push_64(BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value);
push_64(old_RSP);
push_64(read_eflags());
push_64(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_64(RIP);
if (is_error_code)
push_64(error_code);
// set the RPL field of CS to CPL
branch_far64(&cs_selector, &cs_descriptor, gate_dest_offset, CPL);
// if interrupt gate then set IF to 0
if (!(gate_descriptor.type & 1)) // even is int-gate
BX_CPU_THIS_PTR clear_IF();
BX_CPU_THIS_PTR clear_TF();
BX_CPU_THIS_PTR clear_VM();
BX_CPU_THIS_PTR clear_RF();
BX_CPU_THIS_PTR clear_NT();
return;
}
// else #GP(CS selector + ext)
BX_ERROR(("interrupt(long mode): bad descriptor type=%u, descriptor.dpl=%u, CPL=%u",
(unsigned) cs_descriptor.type, (unsigned) cs_descriptor.dpl, (unsigned) CPL));
BX_ERROR(("cs.segment = %u", (unsigned) cs_descriptor.segment));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
#endif
void BX_CPU_C::protected_mode_int(Bit8u vector, bx_bool is_INT, bx_bool is_error_code, Bit16u error_code)
{
// protected mode interrupt
Bit32u dword1, dword2;
bx_descriptor_t gate_descriptor, cs_descriptor;
bx_selector_t cs_selector;
Bit16u raw_tss_selector;
bx_selector_t tss_selector;
bx_descriptor_t tss_descriptor;
Bit16u gate_dest_selector;
Bit32u gate_dest_offset;
Bit32u temp_ESP;
// interrupt vector must be within IDT table limits,
// else #GP(vector number*8 + 2 + EXT)
if ( (vector*8 + 7) > BX_CPU_THIS_PTR idtr.limit) {
BX_DEBUG(("IDT.limit = %04x", (unsigned) BX_CPU_THIS_PTR idtr.limit));
BX_DEBUG(("IDT.base = %06x", (unsigned) BX_CPU_THIS_PTR idtr.base));
BX_DEBUG(("interrupt vector must be within IDT table limits"));
BX_DEBUG(("interrupt(): vector > idtr.limit"));
exception(BX_GP_EXCEPTION, vector*8 + 2, 0);
}
// descriptor AR byte must indicate interrupt gate, trap gate,
// or task gate, else #GP(vector*8 + 2 + EXT)
access_linear(BX_CPU_THIS_PTR idtr.base + vector*8, 4, 0,
BX_READ, &dword1);
access_linear(BX_CPU_THIS_PTR idtr.base + vector*8 + 4, 4, 0,
BX_READ, &dword2);
parse_descriptor(dword1, dword2, &gate_descriptor);
if ((gate_descriptor.valid==0) || gate_descriptor.segment) {
BX_DEBUG(("interrupt(): gate descriptor is not valid sys seg (vector=0x%02x)", vector));
exception(BX_GP_EXCEPTION, vector*8 + 2, 0);
}
switch (gate_descriptor.type) {
case BX_TASK_GATE:
case BX_286_INTERRUPT_GATE:
case BX_286_TRAP_GATE:
case BX_386_INTERRUPT_GATE:
case BX_386_TRAP_GATE:
break;
default:
BX_ERROR(("interrupt(): gate.type(%u) != {5,6,7,14,15}",
(unsigned) gate_descriptor.type));
exception(BX_GP_EXCEPTION, vector*8 + 2, 0);
}
// if software interrupt, then gate descripor DPL must be >= CPL,
// else #GP(vector * 8 + 2 + EXT)
if (is_INT && (gate_descriptor.dpl < CPL)) {
BX_DEBUG(("interrupt(): is_INT && (dpl < CPL)"));
exception(BX_GP_EXCEPTION, vector*8 + 2, 0);
}
// Gate must be present, else #NP(vector * 8 + 2 + EXT)
if (! IS_PRESENT(gate_descriptor)) {
BX_ERROR(("interrupt(): gate not present"));
exception(BX_NP_EXCEPTION, vector*8 + 2, 0);
}
switch (gate_descriptor.type) {
case BX_TASK_GATE:
// examine selector to TSS, given in task gate descriptor
raw_tss_selector = gate_descriptor.u.taskgate.tss_selector;
parse_selector(raw_tss_selector, &tss_selector);
// must specify global in the local/global bit,
// else #GP(TSS selector)
if (tss_selector.ti) {
BX_PANIC(("interrupt: tss_selector.ti=1"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// index must be within GDT limits, else #TS(TSS selector)
fetch_raw_descriptor(&tss_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &tss_descriptor);
// AR byte must specify available TSS,
// else #GP(TSS selector)
if (tss_descriptor.valid==0 || tss_descriptor.segment) {
BX_ERROR(("exception: TSS selector points to bad TSS"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
if (tss_descriptor.type!=9 && tss_descriptor.type!=1) {
BX_ERROR(("exception: TSS selector points to bad TSS"));
exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// TSS must be present, else #NP(TSS selector)
if (! IS_PRESENT(tss_descriptor)) {
BX_ERROR(("exception: TSS descriptor.p == 0"));
exception(BX_NP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
}
// switch tasks with nesting to TSS
task_switch(&tss_selector, &tss_descriptor,
BX_TASK_FROM_CALL_OR_INT, dword1, dword2);
// if interrupt was caused by fault with error code
// stack limits must allow push of 2 more bytes, else #SS(0)
// push error code onto stack
if (is_error_code) {
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.d_b)
push_32(error_code);
else
push_16(error_code);
}
// instruction pointer must be in CS limit, else #GP(0)
if (EIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
BX_ERROR(("exception(): EIP > CS.limit"));
exception(BX_GP_EXCEPTION, 0, 0);
}
return;
case BX_286_INTERRUPT_GATE:
case BX_286_TRAP_GATE:
case BX_386_INTERRUPT_GATE:
case BX_386_TRAP_GATE:
gate_dest_selector = gate_descriptor.u.gate.dest_selector;
gate_dest_offset = gate_descriptor.u.gate.dest_offset;
// examine CS selector and descriptor given in gate descriptor
// selector must be non-null else #GP(EXT)
if ((gate_dest_selector & 0xfffc) == 0) {
BX_ERROR(("int_trap_gate(): selector null"));
exception(BX_GP_EXCEPTION, 0, 0);
}
parse_selector(gate_dest_selector, &cs_selector);
// selector must be within its descriptor table limits
// else #GP(selector+EXT)
fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
parse_descriptor(dword1, dword2, &cs_descriptor);
// descriptor AR byte must indicate code seg
// and code segment descriptor DPL<=CPL, else #GP(selector+EXT)
if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
IS_DATA_SEGMENT(cs_descriptor.type) ||
cs_descriptor.dpl>CPL)
{
BX_ERROR(("interrupt(): not accessable or not code segment cs=0x%04x", cs_selector.value));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// segment must be present, else #NP(selector + EXT)
if (! IS_PRESENT(cs_descriptor)) {
BX_ERROR(("interrupt(): segment not present"));
exception(BX_NP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// if code segment is non-conforming and DPL < CPL then
// INTERRUPT TO INNER PRIVILEGE:
if(IS_CODE_SEGMENT_NON_CONFORMING(cs_descriptor.type) && (cs_descriptor.dpl < CPL))
{
Bit16u old_SS, old_CS, SS_for_cpl_x;
Bit32u ESP_for_cpl_x, old_EIP, old_ESP;
bx_descriptor_t ss_descriptor;
bx_selector_t ss_selector;
int bytes;
int is_v8086_mode = v8086_mode();
BX_DEBUG(("interrupt(): INTERRUPT TO INNER PRIVILEGE"));
if (is_v8086_mode && cs_descriptor.dpl != 0) {
// if code segment DPL != 0 then #GP(new code segment selector)
BX_ERROR(("interrupt(): code segment DPL != 0 in v8086 mode"));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// check selector and descriptor for new stack in current TSS
get_SS_ESP_from_TSS(cs_descriptor.dpl,
&SS_for_cpl_x, &ESP_for_cpl_x);
// Selector must be non-null else #TS(EXT)
if ((SS_for_cpl_x & 0xfffc) == 0) {
BX_ERROR(("interrupt(): SS selector null"));
exception(BX_TS_EXCEPTION, 0, 0); /* TS(ext) */
}
// selector index must be within its descriptor table limits
// else #TS(SS selector + EXT)
parse_selector(SS_for_cpl_x, &ss_selector);
// fetch 2 dwords of descriptor; call handles out of limits checks
fetch_raw_descriptor(&ss_selector, &dword1, &dword2, BX_TS_EXCEPTION);
parse_descriptor(dword1, dword2, &ss_descriptor);
// selector rpl must = dpl of code segment,
// else #TS(SS selector + ext)
if (ss_selector.rpl != cs_descriptor.dpl) {
BX_ERROR(("interrupt(): SS.rpl != CS.dpl"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// stack seg DPL must = DPL of code segment,
// else #TS(SS selector + ext)
if (ss_descriptor.dpl != cs_descriptor.dpl) {
BX_ERROR(("interrupt(): SS.dpl != CS.dpl"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// descriptor must indicate writable data segment,
// else #TS(SS selector + EXT)
if (ss_descriptor.valid==0 || ss_descriptor.segment==0 ||
IS_CODE_SEGMENT(ss_descriptor.type) ||
!IS_DATA_SEGMENT_WRITEABLE(ss_descriptor.type))
{
BX_ERROR(("interrupt(): SS is not writable data segment"));
exception(BX_TS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// seg must be present, else #SS(SS selector + ext)
if (! IS_PRESENT(ss_descriptor)) {
BX_ERROR(("interrupt(): SS not present"));
exception(BX_SS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
if (gate_descriptor.type>=14) {
// 386 int/trap gate
// new stack must have room for 20|24 bytes, else #SS(0)
if (is_error_code)
bytes = 24;
else
bytes = 20;
if (is_v8086_mode)
bytes += 16;
}
else {
// new stack must have room for 10|12 bytes, else #SS(0)
if (is_error_code)
bytes = 12;
else
bytes = 10;
if (is_v8086_mode) {
bytes += 8;
BX_PANIC(("interrupt: int/trap gate VM"));
}
}
// new stack must have enough room, else #SS(seg selector)
if (!can_push(&ss_descriptor, ESP_for_cpl_x, bytes))
{
BX_DEBUG(("interrupt(): new stack doesn't have room for %u bytes", (unsigned) bytes));
exception(BX_SS_EXCEPTION, SS_for_cpl_x & 0xfffc, 0);
}
// IP must be within CS segment boundaries, else #GP(0)
if (gate_dest_offset > cs_descriptor.u.segment.limit_scaled) {
BX_DEBUG(("interrupt(): gate EIP > CS.limit"));
exception(BX_GP_EXCEPTION, 0, 0);
}
old_ESP = ESP;
old_SS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value;
old_EIP = EIP;
old_CS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
// Prepare new stack segment
bx_segment_reg_t new_stack;
new_stack.selector = ss_selector;
new_stack.cache = ss_descriptor;
new_stack.selector.rpl = cs_descriptor.dpl;
// add cpl to the selector value
new_stack.selector.value = (0xfffc & new_stack.selector.value) |
new_stack.selector.rpl;
bx_bool user = (cs_descriptor.dpl == 3);
if (ss_descriptor.u.segment.d_b)
temp_ESP = ESP_for_cpl_x;
else
temp_ESP = (Bit16u) ESP_for_cpl_x;
if (is_v8086_mode)
{
if (gate_descriptor.type>=14) { // 386 int/trap gate
write_new_stack_dword(&new_stack, temp_ESP-4, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
write_new_stack_dword(&new_stack, temp_ESP-8, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
write_new_stack_dword(&new_stack, temp_ESP-12, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
write_new_stack_dword(&new_stack, temp_ESP-16, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
temp_ESP -= 16;
}
else {
write_new_stack_word(&new_stack, temp_ESP-2, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value);
write_new_stack_word(&new_stack, temp_ESP-4, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value);
write_new_stack_word(&new_stack, temp_ESP-6, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value);
write_new_stack_word(&new_stack, temp_ESP-8, user,
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value);
temp_ESP -= 8;
}
}
if (gate_descriptor.type>=14) { // 386 int/trap gate
// push long pointer to old stack onto new stack
write_new_stack_dword(&new_stack, temp_ESP-4, user, old_SS);
write_new_stack_dword(&new_stack, temp_ESP-8, user, old_ESP);
write_new_stack_dword(&new_stack, temp_ESP-12, user, read_eflags());
write_new_stack_dword(&new_stack, temp_ESP-16, user, old_CS);
write_new_stack_dword(&new_stack, temp_ESP-20, user, old_EIP);
temp_ESP -= 20;
if (is_error_code) {
temp_ESP -= 4;
write_new_stack_dword(&new_stack, temp_ESP, user, error_code);
}
}
else { // 286 int/trap gate
// push long pointer to old stack onto new stack
write_new_stack_word(&new_stack, temp_ESP-2, user, old_SS);
write_new_stack_word(&new_stack, temp_ESP-4, user, (Bit16u) old_ESP);
write_new_stack_word(&new_stack, temp_ESP-6, user, read_flags());
write_new_stack_word(&new_stack, temp_ESP-8, user, old_CS);
write_new_stack_word(&new_stack, temp_ESP-10, user, (Bit16u) old_EIP);
temp_ESP -= 10;
if (is_error_code) {
temp_ESP -= 2;
write_new_stack_word(&new_stack, temp_ESP, user, error_code);
}
}
// load new SS:SP values from TSS
load_ss(&ss_selector, &ss_descriptor, cs_descriptor.dpl);
if (ss_descriptor.u.segment.d_b)
ESP = temp_ESP;
else
SP = (Bit16u) temp_ESP;
// load new CS:IP values from gate
// set CPL to new code segment DPL
// set RPL of CS to CPL
load_cs(&cs_selector, &cs_descriptor, cs_descriptor.dpl);
EIP = gate_dest_offset;
// if INTERRUPT GATE set IF to 0
if (!(gate_descriptor.type & 1)) // even is int-gate
BX_CPU_THIS_PTR clear_IF();
BX_CPU_THIS_PTR clear_TF();
BX_CPU_THIS_PTR clear_VM();
BX_CPU_THIS_PTR clear_RF();
BX_CPU_THIS_PTR clear_NT();
if (is_v8086_mode)
{
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.valid = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.valid = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.valid = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.valid = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value = 0;
}
return;
}
if (v8086_mode()) {
// if code segment DPL != 0 then #GP(new code segment selector)
BX_ERROR(("interrupt(): code seg DPL != 0 in v8086 mode"));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
}
// if code segment is conforming OR code segment DPL = CPL then
// INTERRUPT TO SAME PRIVILEGE LEVEL:
if (IS_CODE_SEGMENT_CONFORMING(cs_descriptor.type) || cs_descriptor.dpl==CPL)
{
int bytes;
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
temp_ESP = ESP;
else
temp_ESP = SP;
BX_DEBUG(("int_trap_gate286(): INTERRUPT TO SAME PRIVILEGE"));
// Current stack limits must allow pushing 6|8 bytes, else #SS(0)
if (gate_descriptor.type >= 14) { // 386 gate
if (is_error_code)
bytes = 16;
else
bytes = 12;
}
else { // 286 gate
if (is_error_code)
bytes = 8;
else
bytes = 6;
}
if (! can_push(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache, temp_ESP, bytes))
{
BX_DEBUG(("interrupt(): stack doesn't have room"));
exception(BX_SS_EXCEPTION, 0, 0);
}
// EIP must be in CS limit else #GP(0)
if (gate_dest_offset > cs_descriptor.u.segment.limit_scaled) {
BX_ERROR(("interrupt(): IP > cs descriptor limit"));
exception(BX_GP_EXCEPTION, 0, 0);
}
// push flags onto stack
// push current CS selector onto stack
// push return offset onto stack
if (gate_descriptor.type >= 14) { // 386 gate
push_32(read_eflags());
push_32(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_32(EIP);
if (is_error_code)
push_32(error_code);
}
else { // 286 gate
push_16(read_flags());
push_16(BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value);
push_16(IP);
if (is_error_code)
push_16(error_code);
}
// load CS:IP from gate
// load CS descriptor
// set the RPL field of CS to CPL
load_cs(&cs_selector, &cs_descriptor, CPL);
EIP = gate_dest_offset;
// if interrupt gate then set IF to 0
if (!(gate_descriptor.type & 1)) // even is int-gate
BX_CPU_THIS_PTR clear_IF();
BX_CPU_THIS_PTR clear_TF();
BX_CPU_THIS_PTR clear_NT();
BX_CPU_THIS_PTR clear_VM();
BX_CPU_THIS_PTR clear_RF();
return;
}
// else #GP(CS selector + ext)
BX_DEBUG(("interrupt: bad descriptor"));
BX_DEBUG(("type=%u, descriptor.dpl=%u, CPL=%u",
(unsigned) cs_descriptor.type, (unsigned) cs_descriptor.dpl,
(unsigned) CPL));
BX_DEBUG(("cs.segment = %u", (unsigned) cs_descriptor.segment));
exception(BX_GP_EXCEPTION, cs_selector.value & 0xfffc, 0);
break;
default:
BX_PANIC(("bad descriptor type in interrupt()!"));
break;
}
}
void BX_CPU_C::real_mode_int(Bit8u vector, bx_bool is_INT, bx_bool is_error_code, Bit16u error_code)
{
// real mode interrupt
Bit16u cs_selector, ip;
if ((vector*4+3) > BX_CPU_THIS_PTR idtr.limit) {
BX_ERROR(("interrupt(real mode) vector > idtr.limit"));
exception(BX_GP_EXCEPTION, 0, 0);
}
push_16(read_flags());
cs_selector = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
push_16(cs_selector);
ip = EIP;
push_16(ip);
access_linear(BX_CPU_THIS_PTR idtr.base + 4 * vector, 2, 0, BX_READ, &ip);
EIP = (Bit32u) ip;
access_linear(BX_CPU_THIS_PTR idtr.base + 4 * vector + 2, 2, 0, BX_READ, &cs_selector);
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], cs_selector);
/* INT affects the following flags: I,T */
BX_CPU_THIS_PTR clear_IF();
BX_CPU_THIS_PTR clear_TF();
#if BX_CPU_LEVEL >= 4
BX_CPU_THIS_PTR clear_AC();
#endif
BX_CPU_THIS_PTR clear_RF();
}
void BX_CPU_C::interrupt(Bit8u vector, bx_bool is_INT, bx_bool is_error_code, Bit16u error_code)
{
#if BX_DEBUGGER
BX_CPU_THIS_PTR show_flag |= Flag_intsig;
#if BX_DEBUG_LINUX
if (bx_dbg.linux_syscall) {
if (vector == 0x80) bx_dbg_linux_syscall(BX_CPU_ID);
}
#endif
bx_dbg_interrupt(BX_CPU_ID, vector, error_code);
#endif
BX_DEBUG(("interrupt(): vector = %u, INT = %u, EXT = %u",
(unsigned) vector, (unsigned) is_INT, (unsigned) BX_CPU_THIS_PTR EXT));
BX_INSTR_INTERRUPT(BX_CPU_ID, vector);
invalidate_prefetch_q();
// Discard any traps and inhibits for new context; traps will
// resume upon return.
BX_CPU_THIS_PTR debug_trap = 0;
BX_CPU_THIS_PTR inhibit_mask = 0;
BX_CPU_THIS_PTR save_cs = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS];
BX_CPU_THIS_PTR save_ss = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS];
BX_CPU_THIS_PTR save_eip = RIP;
BX_CPU_THIS_PTR save_esp = RSP;
#if BX_SUPPORT_X86_64
if (long_mode()) {
long_mode_int(vector, is_INT, is_error_code, error_code);
return;
}
#endif
if(real_mode()) {
real_mode_int(vector, is_INT, is_error_code, error_code);
}
else {
protected_mode_int(vector, is_INT, is_error_code, error_code);
}
}
// vector: 0..255: vector in IDT
// error_code: if exception generates and error, push this error code
void BX_CPU_C::exception(unsigned vector, Bit16u error_code, bx_bool is_INT)
{
unsigned exception_type = 0, exception_class = BX_EXCEPTION_CLASS_FAULT;
bx_bool push_error = 0;
invalidate_prefetch_q();
UNUSED(is_INT);
BX_INSTR_EXCEPTION(BX_CPU_ID, vector);
#if BX_DEBUGGER
bx_dbg_exception(BX_CPU_ID, vector, error_code);
#endif
BX_DEBUG(("exception(0x%02x): error_code=%04x", vector, error_code));
// if not initial error, restore previous register values from
// previous attempt to handle exception
if (BX_CPU_THIS_PTR errorno) {
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS] = BX_CPU_THIS_PTR save_cs;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS] = BX_CPU_THIS_PTR save_ss;
RIP = BX_CPU_THIS_PTR save_eip;
RSP = BX_CPU_THIS_PTR save_esp;
}
BX_CPU_THIS_PTR errorno++;
if (BX_CPU_THIS_PTR errorno >= 3 ||
// if 1st was a double fault (software INT?), then shutdown
(BX_CPU_THIS_PTR errorno == 2 && BX_CPU_THIS_PTR curr_exception[0]==BX_ET_DOUBLE_FAULT))
{
debug(BX_CPU_THIS_PTR prev_rip); // print debug information to the log
#if BX_DEBUGGER
// trap into debugger (similar as done when PANIC occured)
bx_debug_break();
#endif
if (SIM->get_param_bool(BXPN_RESET_ON_TRIPLE_FAULT)->get()) {
BX_ERROR(("exception(): 3rd (%d) exception with no resolution, shutdown status is %02xh, resetting", vector, DEV_cmos_get_reg(0x0f)));
bx_pc_system.Reset(BX_RESET_SOFTWARE);
}
else {
BX_PANIC(("exception(): 3rd (%d) exception with no resolution", vector));
BX_ERROR(("WARNING: Any simulation after this point is completely bogus !"));
shutdown();
}
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
// note: fault-class exceptions _except_ #DB set RF in
// eflags image.
switch (vector) {
case BX_DE_EXCEPTION: // DIV by 0
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_CONTRIBUTORY;
break;
case BX_DB_EXCEPTION: // debug exceptions
push_error = 0;
// Instruction fetch breakpoint - FAULT
// Data read or write breakpoint - TRAP
// I/O read or write breakpoint - TRAP
// General detect condition - FAULT
// Single-step - TRAP
// Task-switch - TRAP
exception_class = BX_EXCEPTION_CLASS_TRAP; // FIXME !
exception_type = BX_ET_BENIGN;
break;
case 2: // NMI
push_error = 0;
exception_type = BX_ET_BENIGN;
break;
case BX_BP_EXCEPTION: // breakpoint
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_TRAP;
exception_type = BX_ET_BENIGN;
break;
case BX_OF_EXCEPTION: // overflow
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_TRAP;
exception_type = BX_ET_BENIGN;
break;
case BX_BR_EXCEPTION: // bounds check
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
case BX_UD_EXCEPTION: // invalid opcode
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
case BX_NM_EXCEPTION: // device not available
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
case BX_DF_EXCEPTION: // double fault
push_error = 1;
error_code = 0;
exception_class = BX_EXCEPTION_CLASS_ABORT;
exception_type = BX_ET_DOUBLE_FAULT;
break;
case 9: // coprocessor segment overrun (286,386 only)
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_ABORT;
exception_type = BX_ET_CONTRIBUTORY;
BX_PANIC(("exception(9): unfinished"));
break;
case BX_TS_EXCEPTION: // invalid TSS
push_error = 1;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_CONTRIBUTORY;
break;
case BX_NP_EXCEPTION: // segment not present
push_error = 1;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_CONTRIBUTORY;
break;
case BX_SS_EXCEPTION: // stack fault
push_error = 1;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_CONTRIBUTORY;
break;
case BX_GP_EXCEPTION: // general protection
push_error = 1;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_CONTRIBUTORY;
break;
case BX_PF_EXCEPTION: // page fault
push_error = 1;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_PAGE_FAULT;
break;
case 15: // reserved
BX_PANIC(("exception(15): reserved"));
push_error = 0;
exception_type = 0;
break;
case BX_MF_EXCEPTION: // floating-point error
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
#if BX_CPU_LEVEL >= 4
case BX_AC_EXCEPTION: // alignment check
BX_PANIC(("exception(): alignment-check, vector 17 not implemented"));
push_error = 1;
error_code = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
#endif
#if BX_CPU_LEVEL >= 5
case BX_MC_EXCEPTION: // machine check
BX_PANIC(("exception(): machine-check, vector 18 not implemented"));
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_ABORT;
exception_type = BX_ET_BENIGN;
break;
#if BX_SUPPORT_SSE
case BX_XM_EXCEPTION: // SIMD Floating-Point exception
push_error = 0;
exception_class = BX_EXCEPTION_CLASS_FAULT;
exception_type = BX_ET_BENIGN;
break;
#endif
#endif
default:
BX_PANIC(("exception(%u): bad vector", (unsigned) vector));
exception_type = BX_ET_BENIGN;
push_error = 0; // keep compiler happy for now
break;
}
if (exception_class == BX_EXCEPTION_CLASS_FAULT)
{
// restore RIP/RSP to value before error occurred
RIP = BX_CPU_THIS_PTR prev_rip;
if (BX_CPU_THIS_PTR speculative_rsp)
RSP = BX_CPU_THIS_PTR prev_rsp;
if (vector != BX_DB_EXCEPTION) BX_CPU_THIS_PTR assert_RF();
}
if (exception_type != BX_ET_PAGE_FAULT) {
// Page faults have different format
error_code = (error_code & 0xfffe) | BX_CPU_THIS_PTR EXT;
}
else {
// FIXME: special format error returned for page faults ?
}
BX_CPU_THIS_PTR EXT = 1;
/* if we've already had 1st exception, see if 2nd causes a
* Double Fault instead. Otherwise, just record 1st exception
*/
if (BX_CPU_THIS_PTR errorno >= 2) {
if (is_exception_OK[BX_CPU_THIS_PTR curr_exception[0]][exception_type])
BX_CPU_THIS_PTR curr_exception[1] = exception_type;
else {
BX_CPU_THIS_PTR curr_exception[1] = BX_ET_DOUBLE_FAULT;
vector = BX_DF_EXCEPTION;
}
}
else {
BX_CPU_THIS_PTR curr_exception[0] = exception_type;
}
if (real_mode()) {
// not INT, no error code pushed
BX_CPU_THIS_PTR interrupt(vector, 0, 0, 0);
BX_CPU_THIS_PTR errorno = 0; // error resolved
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
else {
BX_CPU_THIS_PTR interrupt(vector, 0, push_error, error_code);
BX_CPU_THIS_PTR errorno = 0; // error resolved
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
}
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