Make kernel stack unwinding feature of ARM DS-5 Streamline's optional at run time instead of build time.

gator kernel stack unwinding

diff --git a/gator-driver/gator_backtrace.c b/gator-driver/gator_backtrace.c
index 0670d6c..903e964 100644
--- a/gator-driver/gator_backtrace.c
+++ b/gator-driver/gator_backtrace.c
@@ -130,17 +130,13 @@ static int report_trace(struct stackframe *frame, void *d)
 }
 #endif
 
-// Uncomment the following line to enable kernel stack unwinding within gator, note it can also be defined from the Makefile
-// #define GATOR_KERNEL_STACK_UNWINDING
 static void kernel_backtrace(int cpu, struct pt_regs *const regs)
 {
 #if defined(__arm__) || defined(__aarch64__)
-#ifdef GATOR_KERNEL_STACK_UNWINDING
-	int depth = gator_backtrace_depth;
-#else
 	int depth = 1;
-#endif
 	struct stackframe frame;
+    if (kernel_stack_unwinding)
+        depth = gator_backtrace_depth;
 	if (depth == 0)
 		depth = 1;
 #if defined(__arm__)
diff --git a/gator-driver/gator_main.c b/gator-driver/gator_main.c
index 46fe31d..76765b5 100644
--- a/gator-driver/gator_main.c
+++ b/gator-driver/gator_main.c
@@ -1411,6 +1411,10 @@ static void __exit gator_module_exit(void)
 	gatorfs_unregister();
 }
 
+/* module parameter controlling kernel stack tracing */
+bool kernel_stack_unwinding = 0; /* off by default */
+module_param(kernel_stack_unwinding, bool, 0644);
+MODULE_PARM_DESC(kernel_stack_unwinding, "Allow gator to unwind kernel stack.");
 module_init(gator_module_init);
 module_exit(gator_module_exit);