diff -r 97eebddaae84 -r 3ac8305dbf60 src/arch/riscv/process.cc
--- a/src/arch/riscv/process.cc	Wed Nov 09 14:27:40 2016 -0600
+++ b/src/arch/riscv/process.cc	Wed Jan 18 17:39:18 2017 +0000
@@ -216,7 +216,13 @@
 RiscvISA::IntReg
 RiscvLiveProcess::getSyscallArg(ThreadContext *tc, int &i)
 {
-    return tc->readIntReg(SyscallArgumentRegs[i++]);
+    // RISC-V only has four system call argument registers by convention, so
+    // if a larger index is requested return 0
+    RiscvISA::IntReg retval = 0;
+    if (i < 4)
+        retval = tc->readIntReg(SyscallArgumentRegs[i]);
+    i++;
+    return retval;
 }
 
 void