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////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001-2019 The Bochs Project
//
// 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., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
/* pass zero in check_rpl if no needed selector RPL checking for
non-conforming segments */
void BX_CPU_C::check_cs(bx_descriptor_t *descriptor, Bit16u cs_raw, Bit8u check_rpl, Bit8u check_cpl)
{
// descriptor AR byte must indicate code segment else #GP(selector)
if (descriptor->valid==0 || descriptor->segment==0 ||
IS_DATA_SEGMENT(descriptor->type))
{
BX_ERROR(("check_cs(0x%04x): not a valid code segment !", cs_raw));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
#if BX_SUPPORT_X86_64
if (long_mode()) {
if (descriptor->u.segment.l && descriptor->u.segment.d_b) {
BX_ERROR(("check_cs(0x%04x): Both CS.L and CS.D_B bits enabled !", cs_raw));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
}
#endif
// if non-conforming, code segment descriptor DPL must = CPL else #GP(selector)
if (IS_CODE_SEGMENT_NON_CONFORMING(descriptor->type)) {
if (descriptor->dpl != check_cpl) {
BX_ERROR(("check_cs(0x%04x): non-conforming code seg descriptor dpl != cpl, dpl=%d, cpl=%d",
cs_raw, descriptor->dpl, check_cpl));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
/* RPL of destination selector must be <= CPL else #GP(selector) */
if (check_rpl > check_cpl) {
BX_ERROR(("check_cs(0x%04x): non-conforming code seg selector rpl > cpl, rpl=%d, cpl=%d",
cs_raw, check_rpl, check_cpl));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
}
// if conforming, then code segment descriptor DPL must <= CPL else #GP(selector)
else {
if (descriptor->dpl > check_cpl) {
BX_ERROR(("check_cs(0x%04x): conforming code seg descriptor dpl > cpl, dpl=%d, cpl=%d",
cs_raw, descriptor->dpl, check_cpl));
exception(BX_GP_EXCEPTION, cs_raw & 0xfffc);
}
}
// code segment must be present else #NP(selector)
if (! descriptor->p) {
BX_ERROR(("check_cs(0x%04x): code segment not present !", cs_raw));
exception(BX_NP_EXCEPTION, cs_raw & 0xfffc);
}
}
void BX_CPP_AttrRegparmN(3)
BX_CPU_C::load_cs(bx_selector_t *selector, bx_descriptor_t *descriptor, Bit8u cpl)
{
// Add cpl to the selector value.
selector->value = (0xfffc & selector->value) | cpl;
touch_segment(selector, descriptor);
#ifdef BX_SUPPORT_CS_LIMIT_DEMOTION
// Handle special case of CS.LIMIT demotion (new descriptor limit is
// smaller than current one)
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled > descriptor->u.segment.limit_scaled)
BX_CPU_THIS_PTR iCache.flushICacheEntries();
#endif
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector = *selector;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache = *descriptor;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.rpl = cpl;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.valid = SegValidCache;
#if BX_SUPPORT_X86_64
if (long_mode()) {
handleCpuModeChange();
}
#endif
updateFetchModeMask(/* CS reloaded */);
#if BX_CPU_LEVEL >= 4
handleAlignmentCheck(/* CPL change */);
#endif
// Loading CS will invalidate the EIP fetch window.
invalidate_prefetch_q();
}
void BX_CPU_C::branch_far(bx_selector_t *selector, bx_descriptor_t *descriptor, bx_address rip, unsigned cpl)
{
#if BX_SUPPORT_MONITOR_MWAIT
BX_CPU_THIS_PTR monitor.reset_monitorx(); // reset MONITORX after every far control transfer
#endif
#if BX_SUPPORT_X86_64
if (long_mode() && descriptor->u.segment.l) {
if (! IsCanonical(rip)) {
BX_ERROR(("branch_far: canonical RIP violation"));
exception(BX_GP_EXCEPTION, 0);
}
}
else
#endif
{
#if BX_SUPPORT_CET
if (ShadowStackEnabled(cpl)) {
if (GET32H(SSP) != 0) {
BX_ERROR(("branch_far64: 64-bit SSP when jumping to legacy mode"));
exception(BX_GP_EXCEPTION, 0);
}
}
#endif
rip &= 0xffffffff;
/* instruction pointer must be in code segment limit else #GP(0) */
if (rip > descriptor->u.segment.limit_scaled) {
BX_ERROR(("branch_far: RIP > limit"));
exception(BX_GP_EXCEPTION, 0);
}
}
/* Load CS:IP from destination pointer */
/* Load CS-cache with new segment descriptor */
load_cs(selector, descriptor, cpl);
/* Change the RIP value */
RIP = rip;
}
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