290 lines
9.7 KiB
C++
Executable File
290 lines
9.7 KiB
C++
Executable File
////////////////////////////////////////////////////////////////////////
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// $Id: jmp_far.cc,v 1.15 2008-05-09 18:09:04 sshwarts Exp $
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2005 Stanislav Shwartsman
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// Written by Stanislav Shwartsman [sshwarts at sourceforge net]
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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//
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////////////////////////////////////////////////////////////////////////
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#define NEED_CPU_REG_SHORTCUTS 1
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#include "bochs.h"
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#include "cpu.h"
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#define LOG_THIS BX_CPU_THIS_PTR
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#if BX_SUPPORT_X86_64==0
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// Make life easier merging cpu64 & cpu code.
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#define RIP EIP
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#endif
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void BX_CPP_AttrRegparmN(3)
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BX_CPU_C::jump_protected(bxInstruction_c *i, Bit16u cs_raw, bx_address disp)
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{
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bx_descriptor_t descriptor;
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bx_selector_t selector;
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Bit32u dword1, dword2;
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/* destination selector is not null else #GP(0) */
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if ((cs_raw & 0xfffc) == 0) {
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BX_ERROR(("jump_protected: cs == 0"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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parse_selector(cs_raw, &selector);
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/* destination selector index is within its descriptor table
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limits else #GP(selector) */
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fetch_raw_descriptor(&selector, &dword1, &dword2, BX_GP_EXCEPTION);
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/* examine AR byte of destination selector for legal values: */
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parse_descriptor(dword1, dword2, &descriptor);
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if (descriptor.segment) {
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check_cs(&descriptor, cs_raw, BX_SELECTOR_RPL(cs_raw), CPL);
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branch_far64(&selector, &descriptor, disp, CPL);
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return;
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}
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else {
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// call gate DPL must be >= CPL else #GP(gate selector)
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if (descriptor.dpl < CPL) {
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BX_ERROR(("jump_protected: call gate.dpl < CPL"));
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exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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// call gate DPL must be >= gate selector RPL else #GP(gate selector)
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if (descriptor.dpl < selector.rpl) {
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BX_ERROR(("jump_protected: call gate.dpl < selector.rpl"));
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exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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#if BX_SUPPORT_X86_64
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if (long_mode()) {
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if (descriptor.type != BX_386_CALL_GATE) {
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BX_ERROR(("jump_protected: gate type %u unsupported in long mode", (unsigned) descriptor.type));
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exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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}
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else
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#endif
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{
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switch (descriptor.type) {
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case BX_SYS_SEGMENT_AVAIL_286_TSS:
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case BX_SYS_SEGMENT_AVAIL_386_TSS:
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case BX_286_CALL_GATE:
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case BX_386_CALL_GATE:
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case BX_TASK_GATE:
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break;
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default:
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BX_ERROR(("jump_protected: gate type %u unsupported", (unsigned) descriptor.type));
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exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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}
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// task gate must be present else #NP(gate selector)
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if (! IS_PRESENT(descriptor)) {
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BX_ERROR(("jump_protected: call gate.p == 0"));
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exception(BX_NP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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#if BX_SUPPORT_X86_64
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if (long_mode()) {
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jmp_call_gate64(&selector);
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return;
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}
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#endif
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switch (descriptor.type) {
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case BX_SYS_SEGMENT_AVAIL_286_TSS:
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case BX_SYS_SEGMENT_AVAIL_386_TSS:
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if (descriptor.type==BX_SYS_SEGMENT_AVAIL_286_TSS)
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BX_DEBUG(("jump_protected: jump to 286 TSS"));
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else
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BX_DEBUG(("jump_protected: jump to 386 TSS"));
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// SWITCH_TASKS _without_ nesting to TSS
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task_switch(&selector, &descriptor, BX_TASK_FROM_JUMP, dword1, dword2);
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// EIP must be in code seg limit, else #GP(0)
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if (EIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
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BX_ERROR(("jump_protected: EIP not within CS limits"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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return;
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case BX_TASK_GATE:
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jmp_task_gate(&descriptor);
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return;
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case BX_286_CALL_GATE:
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case BX_386_CALL_GATE:
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jmp_call_gate(&descriptor);
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return;
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default: // can't get here
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BX_PANIC(("jump_protected: gate type %u unsupported", (unsigned) descriptor.type));
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exception(BX_GP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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}
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}
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void BX_CPP_AttrRegparmN(1)
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BX_CPU_C::jmp_task_gate(bx_descriptor_t *gate_descriptor)
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{
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Bit16u raw_tss_selector;
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bx_selector_t tss_selector;
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bx_descriptor_t tss_descriptor;
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Bit32u dword1, dword2;
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Bit32u temp_eIP;
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// examine selector to TSS, given in Task Gate descriptor
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// must specify global in the local/global bit else #GP(TSS selector)
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raw_tss_selector = gate_descriptor->u.taskgate.tss_selector;
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parse_selector(raw_tss_selector, &tss_selector);
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if (tss_selector.ti) {
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BX_ERROR(("jmp_task_gate: tss_selector.ti=1"));
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exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
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}
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// index must be within GDT limits else #GP(TSS selector)
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fetch_raw_descriptor(&tss_selector, &dword1, &dword2, BX_GP_EXCEPTION);
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// descriptor AR byte must specify available TSS
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// else #GP(TSS selector)
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parse_descriptor(dword1, dword2, &tss_descriptor);
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if (tss_descriptor.valid==0 || tss_descriptor.segment) {
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BX_ERROR(("jmp_task_gate: TSS selector points to bad TSS"));
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exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
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}
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if (tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_286_TSS &&
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tss_descriptor.type!=BX_SYS_SEGMENT_AVAIL_386_TSS)
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{
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BX_ERROR(("jmp_task_gate: TSS selector points to bad TSS"));
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exception(BX_GP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
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}
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// task state segment must be present, else #NP(tss selector)
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if (! IS_PRESENT(tss_descriptor)) {
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BX_ERROR(("jmp_task_gate: TSS descriptor.p == 0"));
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exception(BX_NP_EXCEPTION, raw_tss_selector & 0xfffc, 0);
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}
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// SWITCH_TASKS _without_ nesting to TSS
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task_switch(&tss_selector, &tss_descriptor, BX_TASK_FROM_JUMP, dword1, dword2);
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// EIP must be within code segment limit, else #GP(0)
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if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.d_b)
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temp_eIP = EIP;
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else
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temp_eIP = IP;
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if (temp_eIP > BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled) {
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BX_ERROR(("jmp_task_gate: EIP > CS.limit"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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}
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void BX_CPP_AttrRegparmN(1)
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BX_CPU_C::jmp_call_gate(bx_descriptor_t *gate_descriptor)
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{
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bx_selector_t gate_cs_selector;
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bx_descriptor_t gate_cs_descriptor;
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Bit32u dword1, dword2;
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if (gate_descriptor->type==BX_286_CALL_GATE)
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BX_DEBUG(("jmp_call_gate: jump to 286 CALL GATE"));
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else
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BX_DEBUG(("jmp_call_gate: jump to 386 CALL GATE"));
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// examine selector to code segment given in call gate descriptor
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// selector must not be null, else #GP(0)
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Bit16u gate_cs_raw = gate_descriptor->u.gate.dest_selector;
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if ((gate_cs_raw & 0xfffc) == 0) {
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BX_ERROR(("jmp_call_gate: CS selector null"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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parse_selector(gate_cs_raw, &gate_cs_selector);
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// selector must be within its descriptor table limits else #GP(CS selector)
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fetch_raw_descriptor(&gate_cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
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parse_descriptor(dword1, dword2, &gate_cs_descriptor);
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// check code-segment descriptor
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check_cs(&gate_cs_descriptor, gate_cs_raw, 0, CPL);
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Bit32u temp_EIP = gate_descriptor->u.gate.dest_offset;
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branch_far32(&gate_cs_selector, &gate_cs_descriptor, temp_EIP, CPL);
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}
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#if BX_SUPPORT_X86_64
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void BX_CPP_AttrRegparmN(1)
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BX_CPU_C::jmp_call_gate64(bx_selector_t *gate_selector)
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{
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bx_selector_t cs_selector;
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Bit32u dword1, dword2, dword3;
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bx_descriptor_t cs_descriptor;
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bx_descriptor_t gate_descriptor;
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BX_DEBUG(("jmp_call_gate64: jump to CALL GATE 64"));
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fetch_raw_descriptor64(gate_selector, &dword1, &dword2, &dword3, BX_GP_EXCEPTION);
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parse_descriptor(dword1, dword2, &gate_descriptor);
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Bit16u dest_selector = gate_descriptor.u.gate.dest_selector;
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// selector must not be null else #GP(0)
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if ((dest_selector & 0xfffc) == 0) {
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BX_ERROR(("jmp_call_gate64: selector in gate null"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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parse_selector(dest_selector, &cs_selector);
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// selector must be within its descriptor table limits,
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// else #GP(code segment selector)
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fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
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parse_descriptor(dword1, dword2, &cs_descriptor);
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// find the RIP in the gate_descriptor
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Bit64u new_RIP = gate_descriptor.u.gate.dest_offset;
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new_RIP |= ((Bit64u)dword3 << 32);
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// AR byte of selected descriptor must indicate code segment,
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// else #GP(code segment selector)
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if (cs_descriptor.valid==0 || cs_descriptor.segment==0 ||
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IS_DATA_SEGMENT(cs_descriptor.type))
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{
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BX_ERROR(("jmp_call_gate64: not code segment in 64-bit call gate"));
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exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
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}
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// In long mode, only 64-bit call gates are allowed, and they must point
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// to 64-bit code segments, else #GP(selector)
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if (! IS_LONG64_SEGMENT(cs_descriptor) || cs_descriptor.u.segment.d_b)
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{
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BX_ERROR(("jmp_call_gate64: not 64-bit code segment in 64-bit call gate"));
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exception(BX_GP_EXCEPTION, dest_selector & 0xfffc, 0);
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}
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// check code-segment descriptor
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check_cs(&cs_descriptor, dest_selector, 0, CPL);
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// and transfer the control
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branch_far64(&cs_selector, &cs_descriptor, new_RIP, CPL);
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}
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#endif
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