sim: Add ability to break at specific kernel function

Adds a GDB callable function that sets a breakpoint at
the beginning of a kernel function.

src/sim/debug.cc

@@ -38,6 +38,8 @@
 #include "sim/global_event.hh"
 #include "sim/sim_events.hh"
 #include "sim/sim_exit.hh"
+#include "cpu/pc_event.hh"
+#include "sim/system.hh"
 
 using namespace std;
 
@@ -87,6 +89,14 @@ schedBreak(Tick when)
     warn("need to stop all queues");
 }
 
+void
+breakAtKernelFunction(const char* funcName)
+{
+    System* curSystem = System::systemList[0];
+    curSystem->addKernelFuncEvent<BreakPCEvent>(funcName,
+                                                "GDB scheduled break", true);
+}
+
 ///
 /// Function to cause the simulator to take a checkpoint from the debugger
 ///

src/sim/debug.hh

@@ -44,6 +44,13 @@
  */
 void schedBreak(Tick when);
 
+/**
+ * Cause the simulator to execute a breakpoint when
+ * the given kernel function is reached
+ * @param funcName the name of the kernel function at which to break
+ */
+void breakAtKernelFunction(const char* funcName);
+
 /** Cause the simulator to return to python to create a checkpoint
  * @param when the cycle to break
  */