289 lines
9.6 KiB
C++
Executable File
289 lines
9.6 KiB
C++
Executable File
////////////////////////////////////////////////////////////////////////
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// $Id: ret_far.cc,v 1.9 2007-02-03 21:36:40 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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#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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#define RSP ESP
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#endif
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void BX_CPP_AttrRegparmN(2)
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BX_CPU_C::return_protected(bxInstruction_c *i, Bit16u pop_bytes)
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{
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Bit16u raw_cs_selector, raw_ss_selector;
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bx_selector_t cs_selector, ss_selector;
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bx_descriptor_t cs_descriptor, ss_descriptor;
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Bit32u stack_param_offset;
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bx_address return_RIP, return_RSP, temp_RSP;
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Bit32u dword1, dword2;
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/* + 6+N*2: SS | +12+N*4: SS | +24+N*8 SS */
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/* + 4+N*2: SP | + 8+N*4: ESP | +16+N*8 RSP */
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/* parm N | + parm N | + parm N */
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/* parm 3 | + parm 3 | + parm 3 */
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/* parm 2 | + parm 2 | + parm 2 */
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/* + 4: parm 1 | + 8: parm 1 | +16: parm 1 */
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/* + 2: CS | + 4: CS | + 8: CS */
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/* + 0: IP | + 0: EIP | + 0: RIP */
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#if BX_SUPPORT_X86_64
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if (StackAddrSize64()) temp_RSP = RSP;
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else
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#endif
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{
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if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b) temp_RSP = ESP;
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else temp_RSP = SP;
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}
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#if BX_SUPPORT_X86_64
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if (i->os64L()) {
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/* operand size=64: 2nd qword on stack must be within stack limits,
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* else #SS(0); */
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if (!can_pop(16))
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{
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BX_ERROR(("return_protected: 2rd qword not in stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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read_virtual_word (BX_SEG_REG_SS, temp_RSP + 8, &raw_cs_selector);
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read_virtual_qword(BX_SEG_REG_SS, temp_RSP + 0, &return_RIP);
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stack_param_offset = 16;
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}
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else
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#endif
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if (i->os32L()) {
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/* operand size=32: 2nd dword on stack must be within stack limits,
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* else #SS(0); */
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if (! can_pop(8))
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{
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BX_ERROR(("return_protected: 2rd dword not in stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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Bit32u return_EIP = 0;
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read_virtual_word (BX_SEG_REG_SS, temp_RSP + 4, &raw_cs_selector);
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read_virtual_dword(BX_SEG_REG_SS, temp_RSP + 0, &return_EIP);
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return_RIP = return_EIP;
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stack_param_offset = 8;
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}
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else {
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/* operand size=16: second word on stack must be within stack limits,
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* else #SS(0); */
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if (! can_pop(4))
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{
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BX_ERROR(("return_protected: 2nd word not in stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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Bit16u return_IP = 0;
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read_virtual_word(BX_SEG_REG_SS, temp_RSP + 2, &raw_cs_selector);
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read_virtual_word(BX_SEG_REG_SS, temp_RSP + 0, &return_IP);
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return_RIP = return_IP;
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stack_param_offset = 4;
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}
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// selector must be non-null else #GP(0)
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if ((raw_cs_selector & 0xfffc) == 0) {
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BX_ERROR(("return_protected: CS selector null"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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parse_selector(raw_cs_selector, &cs_selector);
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// selector index must be within its descriptor table limits,
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// else #GP(selector)
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fetch_raw_descriptor(&cs_selector, &dword1, &dword2, BX_GP_EXCEPTION);
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// descriptor AR byte must indicate code segment, else #GP(selector)
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parse_descriptor(dword1, dword2, &cs_descriptor);
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// return selector RPL must be >= CPL, else #GP(return selector)
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if (cs_selector.rpl < CPL) {
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BX_ERROR(("return_protected: CS.rpl < CPL"));
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exception(BX_GP_EXCEPTION, raw_cs_selector & 0xfffc, 0);
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}
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// check code-segment descriptor
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check_cs(&cs_descriptor, raw_cs_selector, 0, cs_selector.rpl);
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// if return selector RPL == CPL then
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// RETURN TO SAME PRIVILEGE LEVEL
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if (cs_selector.rpl == CPL)
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{
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BX_DEBUG(("return_protected: return to SAME PRIVILEGE LEVEL"));
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// top word on stack must be within stack limits, else #SS(0)
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if (! can_pop(stack_param_offset + pop_bytes)) {
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BX_ERROR(("return_protected: top word not in stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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branch_far64(&cs_selector, &cs_descriptor, return_RIP, CPL);
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#if BX_SUPPORT_X86_64
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if (StackAddrSize64())
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RSP += stack_param_offset + pop_bytes;
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else
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#endif
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{
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if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
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ESP += stack_param_offset + pop_bytes;
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else
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SP += stack_param_offset + pop_bytes;
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}
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return;
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}
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/* RETURN TO OUTER PRIVILEGE LEVEL */
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else {
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/* + 6+N*2: SS | +12+N*4: SS | +24+N*8 SS */
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/* + 4+N*2: SP | + 8+N*4: ESP | +16+N*8 RSP */
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/* parm N | + parm N | + parm N */
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/* parm 3 | + parm 3 | + parm 3 */
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/* parm 2 | + parm 2 | + parm 2 */
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/* + 4: parm 1 | + 8: parm 1 | +16: parm 1 */
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/* + 2: CS | + 4: CS | + 8: CS */
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/* + 0: IP | + 0: EIP | + 0: RIP */
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#if BX_SUPPORT_X86_64
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if (i->os64L()) {
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/* top 32+immediate bytes on stack must be within stack limits, else #SS(0) */
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if (! can_pop(32 + pop_bytes)) {
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BX_ERROR(("return_protected: 32 bytes not within stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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read_virtual_word (BX_SEG_REG_SS, temp_RSP + 24 + pop_bytes, &raw_ss_selector);
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read_virtual_qword(BX_SEG_REG_SS, temp_RSP + 16 + pop_bytes, &return_RSP);
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}
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else
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#endif
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if (i->os32L()) {
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/* top 16+immediate bytes on stack must be within stack limits, else #SS(0) */
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if (! can_pop(16 + pop_bytes)) {
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BX_ERROR(("return_protected: 16 bytes not within stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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Bit32u return_ESP = 0;
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read_virtual_word (BX_SEG_REG_SS, temp_RSP + 12 + pop_bytes, &raw_ss_selector);
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read_virtual_dword(BX_SEG_REG_SS, temp_RSP + 8 + pop_bytes, &return_ESP);
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return_RSP = return_ESP;
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}
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else {
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/* top 8+immediate bytes on stack must be within stack limits, else #SS(0) */
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if (! can_pop(8 + pop_bytes)) {
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BX_ERROR(("return_protected: 8 bytes not within stack limits"));
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exception(BX_SS_EXCEPTION, 0, 0);
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}
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Bit16u return_SP = 0;
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read_virtual_word(BX_SEG_REG_SS, temp_RSP + 6 + pop_bytes, &raw_ss_selector);
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read_virtual_word(BX_SEG_REG_SS, temp_RSP + 4 + pop_bytes, &return_SP);
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return_RSP = return_SP;
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}
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/* selector index must be within its descriptor table limits,
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* else #GP(selector) */
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parse_selector(raw_ss_selector, &ss_selector);
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if ((raw_ss_selector & 0xfffc) == 0) {
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if (long_mode()) {
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if (! IS_LONG64_SEGMENT(cs_descriptor) || (cs_selector.rpl == 3)) {
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BX_ERROR(("return_protected: SS selector null"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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}
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else // not in long or compatibility mode
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{
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BX_ERROR(("return_protected: SS selector null"));
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exception(BX_GP_EXCEPTION, 0, 0);
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}
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}
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fetch_raw_descriptor(&ss_selector, &dword1, &dword2, BX_GP_EXCEPTION);
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parse_descriptor(dword1, dword2, &ss_descriptor);
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/* selector RPL must = RPL of the return CS selector,
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* else #GP(selector) */
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if (ss_selector.rpl != cs_selector.rpl) {
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BX_ERROR(("return_protected: ss.rpl != cs.rpl"));
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exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
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}
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/* descriptor AR byte must indicate a writable data segment,
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* else #GP(selector) */
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if (ss_descriptor.valid==0 || ss_descriptor.segment==0 ||
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IS_CODE_SEGMENT(ss_descriptor.type) ||
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!IS_DATA_SEGMENT_WRITEABLE(ss_descriptor.type))
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{
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BX_ERROR(("return_protected: SS.AR byte not writable data"));
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exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
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}
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/* descriptor dpl must = RPL of the return CS selector,
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* else #GP(selector) */
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if (ss_descriptor.dpl != cs_selector.rpl) {
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BX_ERROR(("return_protected: SS.dpl != cs.rpl"));
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exception(BX_GP_EXCEPTION, raw_ss_selector & 0xfffc, 0);
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}
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/* segment must be present else #SS(selector) */
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if (! IS_PRESENT(ss_descriptor)) {
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BX_ERROR(("return_protected: ss.present == 0"));
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exception(BX_SS_EXCEPTION, raw_ss_selector & 0xfffc, 0);
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}
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branch_far64(&cs_selector, &cs_descriptor, return_RIP, cs_selector.rpl);
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/* load SS:SP from stack */
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/* load SS-cache with return SS descriptor */
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load_ss(&ss_selector, &ss_descriptor, cs_selector.rpl);
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#if BX_SUPPORT_X86_64
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if (StackAddrSize64()) RSP = return_RSP + pop_bytes;
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else
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#endif
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if (ss_descriptor.u.segment.d_b)
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ESP = (Bit32u) return_RSP + pop_bytes;
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else
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SP = (Bit16u) return_RSP + pop_bytes;
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/* check ES, DS, FS, GS for validity */
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validate_seg_regs();
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}
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}
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