From 280617288c2b038e6fc52222eca962016b24b232 Mon Sep 17 00:00:00 2001
From: Stanislav Shwartsman <sshwarts@users.sourceforge.net>
Date: Sun, 20 Apr 2008 18:17:14 +0000
Subject: [PATCH] Mode change in SYSENTER/EXIT/CALL/RET could happen only when
 already in long mode

---
 bochs/cpu/proc_ctrl.cc | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/bochs/cpu/proc_ctrl.cc b/bochs/cpu/proc_ctrl.cc
index c88572c30..259228625 100644
--- a/bochs/cpu/proc_ctrl.cc
+++ b/bochs/cpu/proc_ctrl.cc
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: proc_ctrl.cc,v 1.216 2008-04-20 18:10:32 sshwarts Exp $
+// $Id: proc_ctrl.cc,v 1.217 2008-04-20 18:17:14 sshwarts Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2001  MandrakeSoft S.A.
@@ -2099,6 +2099,10 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSENTER(bxInstruction_c *i)
   BX_CPU_THIS_PTR updateFetchModeMask();
 #endif
 
+#if BX_SUPPORT_X86_64
+  handleCpuModeChange(); // mode change could happen only when in long_mode()
+#endif
+
 #if BX_CPU_LEVEL >= 4 && BX_SUPPORT_ALIGNMENT_CHECK
   BX_CPU_THIS_PTR alignment_check_mask = LPF_MASK; // CPL=0
 #endif
@@ -2133,8 +2137,6 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSENTER(bxInstruction_c *i)
     EIP = (Bit32u) BX_CPU_THIS_PTR msr.sysenter_eip_msr;
   }
 
-  handleCpuModeChange();
-
   BX_INSTR_FAR_BRANCH(BX_CPU_ID, BX_INSTR_IS_SYSENTER,
                       BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value, RIP);
 #else
@@ -2220,6 +2222,10 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSEXIT(bxInstruction_c *i)
   BX_CPU_THIS_PTR updateFetchModeMask();
 #endif
 
+#if BX_SUPPORT_X86_64
+  handleCpuModeChange(); // mode change could happen only when in long_mode()
+#endif
+
 #if BX_CPU_LEVEL >= 4 && BX_SUPPORT_ALIGNMENT_CHECK
   handleAlignmentCheck(); // CPL was modified
 #endif
@@ -2242,8 +2248,6 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSEXIT(bxInstruction_c *i)
   BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.l            = 0;
 #endif
 
-  handleCpuModeChange();
-
   BX_INSTR_FAR_BRANCH(BX_CPU_ID, BX_INSTR_IS_SYSEXIT,
                       BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value, RIP);
 #else
@@ -2298,6 +2302,8 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSCALL(bxInstruction_c *i)
     BX_CPU_THIS_PTR updateFetchModeMask();
 #endif
 
+    handleCpuModeChange(); // mode change could only happen when in long_mode()
+
 #if BX_CPU_LEVEL >= 4 && BX_SUPPORT_ALIGNMENT_CHECK
     BX_CPU_THIS_PTR alignment_check_mask = LPF_MASK; // CPL=0
 #endif
@@ -2377,8 +2383,6 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSCALL(bxInstruction_c *i)
     RIP = temp_RIP;
   }
 
-  handleCpuModeChange();
-
   BX_INSTR_FAR_BRANCH(BX_CPU_ID, BX_INSTR_IS_SYSCALL,
                       BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value, RIP);
 }
@@ -2454,6 +2458,8 @@ void BX_CPP_AttrRegparmN(1) BX_CPU_C::SYSRET(bxInstruction_c *i)
     BX_CPU_THIS_PTR updateFetchModeMask();
 #endif
 
+    handleCpuModeChange(); // mode change could only happen when in long64 mode
+
 #if BX_CPU_LEVEL >= 4 && BX_SUPPORT_ALIGNMENT_CHECK
     handleAlignmentCheck(); // CPL was modified
 #endif