O3CPU: Add a hack to ensure that nextPC is set correctly after syscalls.

Just check CPU's nextPC before and after syscall and if it changes,
update this instruction's nextPC because the syscall must have changed
the nextPC.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/cpu/o3/alpha/dyn_inst_impl.hh b/src/cpu/o3/alpha/dyn_inst_impl.hh
index 6dfe0ccdd..610a313cf 100644
--- a/src/cpu/o3/alpha/dyn_inst_impl.hh
+++ b/src/cpu/o3/alpha/dyn_inst_impl.hh
@@ -161,7 +161,15 @@ template <class Impl>
 void
 AlphaDynInst<Impl>::syscall(int64_t callnum)
 {
+    // HACK: check CPU's nextPC before and after syscall. If it
+    // changes, update this instruction's nextPC because the syscall
+    // must have changed the nextPC.
+    Addr cpu_next_pc = this->cpu->readNextPC(this->threadNumber);
     this->cpu->syscall(callnum, this->threadNumber);
+    Addr new_next_pc = this->cpu->readNextPC(this->threadNumber);
+    if (cpu_next_pc != new_next_pc) {
+        this->setNextPC(new_next_pc);
+    }
 }
 #endif