diff -r f634a34f2f0b -r 4f6f5fa237a3 configs/common/Simulation.py
--- a/configs/common/Simulation.py	Tue Oct 23 04:49:48 2012 -0400
+++ b/configs/common/Simulation.py	Tue Oct 23 20:36:13 2012 +0200
@@ -27,6 +27,7 @@
 #
 # Authors: Lisa Hsu
 
+import sys
 from os import getcwd
 from os.path import join as joinpath
 
@@ -506,3 +507,5 @@
     print 'Exiting @ tick %i because %s' % (m5.curTick(), exit_cause)
     if options.checkpoint_at_end:
         m5.checkpoint(joinpath(cptdir, "cpt.%d"))
+
+    sys.exit(exit_event.getCode())
diff -r f634a34f2f0b -r 4f6f5fa237a3 src/arch/x86/isa/decoder/two_byte_opcodes.isa
--- a/src/arch/x86/isa/decoder/two_byte_opcodes.isa	Tue Oct 23 04:49:48 2012 -0400
+++ b/src/arch/x86/isa/decoder/two_byte_opcodes.isa	Tue Oct 23 20:36:13 2012 +0200
@@ -157,6 +157,9 @@
                         0x21: m5exit({{
                             PseudoInst::m5exit(xc->tcBase(), Rdi);
                         }}, IsNonSpeculative);
+                        0x22: m5fail({{
+                            PseudoInst::m5fail(xc->tcBase(), Rdi, Rsi);
+                        }}, IsNonSpeculative);
                         0x30: m5initparam({{
                             Rax = PseudoInst::initParam(xc->tcBase());
                         }}, IsNonSpeculative);
diff -r f634a34f2f0b -r 4f6f5fa237a3 src/sim/pseudo_inst.hh
--- a/src/sim/pseudo_inst.hh	Tue Oct 23 04:49:48 2012 -0400
+++ b/src/sim/pseudo_inst.hh	Tue Oct 23 20:36:13 2012 +0200
@@ -61,6 +61,7 @@
 uint64_t rpns(ThreadContext *tc);
 void wakeCPU(ThreadContext *tc, uint64_t cpuid);
 void m5exit(ThreadContext *tc, Tick delay);
+void m5fail(ThreadContext *tc, Tick delay, uint64_t code);
 void resetstats(ThreadContext *tc, Tick delay, Tick period);
 void dumpstats(ThreadContext *tc, Tick delay, Tick period);
 void dumpresetstats(ThreadContext *tc, Tick delay, Tick period);
diff -r f634a34f2f0b -r 4f6f5fa237a3 src/sim/pseudo_inst.cc
--- a/src/sim/pseudo_inst.cc	Tue Oct 23 04:49:48 2012 -0400
+++ b/src/sim/pseudo_inst.cc	Tue Oct 23 20:36:13 2012 +0200
@@ -219,6 +219,13 @@
 }
 
 void
+m5fail(ThreadContext *tc, Tick delay, uint64_t code)
+{
+    Tick when = curTick() + delay * SimClock::Int::ns;
+    exitSimLoop("m5_fail instruction encountered", code, when);
+}
+
+void
 loadsymbol(ThreadContext *tc)
 {
     if (!FullSystem)
diff -r f634a34f2f0b -r 4f6f5fa237a3 util/m5/m5.c
--- a/util/m5/m5.c	Tue Oct 23 04:49:48 2012 -0400
+++ b/util/m5/m5.c	Tue Oct 23 20:36:13 2012 +0200
@@ -135,6 +135,15 @@
 }
 
 void
+do_fail(int argc, char *argv[])
+{
+    if (argc < 1 || argc > 2)
+        usage();
+
+    m5_fail((argc > 1) ? strtoul(argv[1], NULL, 0) : 0, strtoul(argv[0], NULL, 0));
+}
+
+void
 do_reset_stats(int argc, char *argv[])
 {
     uint64_t ints[2];
@@ -273,6 +282,7 @@
 
 struct MainFunc mainfuncs[] = {
     { "exit",           do_exit,             "[delay]" },
+    { "fail",           do_fail,             "<code> [delay]" },
     { "resetstats",     do_reset_stats,      "[delay [period]]" },
     { "dumpstats",      do_dump_stats,       "[delay [period]]" },
     { "dumpresetstats", do_dump_reset_stats, "[delay [period]]" },
diff -r f634a34f2f0b -r 4f6f5fa237a3 util/m5/m5op.h
--- a/util/m5/m5op.h	Tue Oct 23 04:49:48 2012 -0400
+++ b/util/m5/m5op.h	Tue Oct 23 20:36:13 2012 +0200
@@ -43,6 +43,7 @@
 void wakeCPU(uint64_t cpuid);
 
 void m5_exit(uint64_t ns_delay);
+void m5_fail(uint64_t ns_delay, uint64_t code);
 uint64_t m5_initparam(void);
 void m5_checkpoint(uint64_t ns_delay, uint64_t ns_period);
 void m5_reset_stats(uint64_t ns_delay, uint64_t ns_period);
diff -r f634a34f2f0b -r 4f6f5fa237a3 util/m5/m5op_x86.S
--- a/util/m5/m5op_x86.S	Tue Oct 23 04:49:48 2012 -0400
+++ b/util/m5/m5op_x86.S	Tue Oct 23 20:36:13 2012 +0200
@@ -48,6 +48,7 @@
 TWO_BYTE_OP(quiesceTime, quiescetime_func)
 TWO_BYTE_OP(rpns, rpns_func)
 TWO_BYTE_OP(m5_exit, exit_func)
+TWO_BYTE_OP(m5_fail, fail_func)
 TWO_BYTE_OP(m5_initparam, initparam_func)
 TWO_BYTE_OP(m5_loadsymbol, loadsymbol_func)
 TWO_BYTE_OP(m5_reset_stats, resetstats_func)
diff -r f634a34f2f0b -r 4f6f5fa237a3 util/m5/m5ops.h
--- a/util/m5/m5ops.h	Tue Oct 23 04:49:48 2012 -0400
+++ b/util/m5/m5ops.h	Tue Oct 23 20:36:13 2012 +0200
@@ -40,6 +40,7 @@
 #define deprecated2_func        0x11 // obsolete ivle
 #define deprecated3_func        0x20 // deprecated exit function
 #define exit_func               0x21
+#define fail_func               0x22
 #define initparam_func          0x30
 #define loadsymbol_func         0x31
 #define resetstats_func         0x40