284 lines
10 KiB
C++
Executable File
284 lines
10 KiB
C++
Executable File
////////////////////////////////////////////////////////////////////////
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// $Id: jmp_far.cc,v 1.1 2005-08-01 22:06:19 sshwarts Exp $
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2001 MandrakeSoft S.A.
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//
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// MandrakeSoft S.A.
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// 43, rue d'Aboukir
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// 75002 Paris - France
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// http://www.linux-mandrake.com/
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// http://www.mandrakesoft.com/
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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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#define NEED_CPU_REG_SHORTCUTS 1
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#include "bochs.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 whithin 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));
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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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Bit16u raw_tss_selector;
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bx_selector_t tss_selector, gate_cs_selector;
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bx_descriptor_t tss_descriptor, gate_cs_descriptor;
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Bit16u gate_cs_raw;
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Bit32u temp_eIP;
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#if BX_SUPPORT_X86_64
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if (BX_CPU_THIS_PTR cpu_mode == BX_MODE_LONG_64) {
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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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#endif
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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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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_INFO(("jump to 286 TSS"));
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//else
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// BX_INFO(("jump to 386 TSS"));
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// Task State Seg must be present, else #NP(TSS selector)
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// checked in task_switch()
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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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// 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: task gate.p == 0"));
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exception(BX_NP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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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 = 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(("jump_protected: 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(("jump_protected: 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!=9 && tss_descriptor.type!=1) {
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BX_ERROR(("jump_protected: 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(("jump_protected: task 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,
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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(("jump_protected: EIP > CS.limit"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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break;
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case BX_286_CALL_GATE:
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BX_DEBUG(("jump_protected: JUMP TO 286 CALL GATE"));
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// 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 not present !"));
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exception(BX_NP_EXCEPTION, cs_raw & 0xfffc, 0);
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}
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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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gate_cs_raw = descriptor.u.gate286.dest_selector;
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if ((gate_cs_raw & 0xfffc) == 0) {
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BX_ERROR(("jump_protected: 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, no need to check selector RPL
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// for non-conforming segments
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check_cs(&gate_cs_descriptor, gate_cs_raw, 0);
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branch_far32(&gate_cs_selector, &gate_cs_descriptor,
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descriptor.u.gate286.dest_offset, CPL);
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return;
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case BX_386_CALL_GATE:
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#if BX_SUPPORT_X86_64
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if (BX_CPU_THIS_PTR msr.lma) { // LONG MODE
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BX_PANIC(("jump to CALL_GATE64 still not implemented"));
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}
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#endif
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// gate must be present else #NP(gate selector)
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if (! IS_PRESENT(descriptor)) {
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BX_ERROR(("jump_protected: task gate.p == 0"));
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exception(BX_NP_EXCEPTION, cs_raw & 0xfffc, 0);
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return;
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}
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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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gate_cs_raw = descriptor.u.gate386.dest_selector;
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if ((gate_cs_raw & 0xfffc) == 0) {
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BX_ERROR(("jump_protected: 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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/*
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STILL NOT IMPLEMENTED ...
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IF (LONG_MODE)
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{
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// in long mode, we need to read the 2nd half of a 16-byte call-gate
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// from the gdt/ldt to get the upper 32 bits of the target RIP
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temp_upper = READ_MEM.q [temp_sel+8]
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// Make sure the extended attribute bits are all zero.
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IF (temp_upper's extended attribute bits != 0)
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EXCEPTION [#GP(temp_sel)]
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// concatenate both halves of RIP
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temp_RIP = tempRIP + (temp_upper SHL 32)
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}
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// set up new CS base, attr, limits
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CS = READ_DESCRIPTOR (temp_desc.segment, clg_chk)
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IF ((64BIT_MODE) && (temp_RIP is non-canonical)
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|| (!64BIT_MODE) && (temp_RIP > CS.limit))
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{
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EXCEPTION [#GP(0)]
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}
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RIP = temp_RIP
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*/
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// check code-segment descriptor, no need to check selector RPL
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// for non-conforming segments
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check_cs(&gate_cs_descriptor, gate_cs_raw, 0);
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// IP must be in code segment limit else #GP(0)
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if ( descriptor.u.gate386.dest_offset >
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gate_cs_descriptor.u.segment.limit_scaled )
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{
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BX_ERROR(("jump_protected: EIP > limit"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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// load CS:IP from call gate
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// load CS cache with new code segment
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// set rpl of CS to CPL
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load_cs(&gate_cs_selector, &gate_cs_descriptor, CPL);
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EIP = descriptor.u.gate386.dest_offset;
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return;
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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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}
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