diff --git a/include/linux/mmiotrace.h b/include/linux/mmiotrace.h
index cb5efd0..579b3b06 100644
--- a/include/linux/mmiotrace.h
+++ b/include/linux/mmiotrace.h
@@ -54,6 +54,12 @@
 }
 #endif /* CONFIG_MMIOTRACE_HOOKS */
 
+/* in kernel/trace/trace_mmiotrace.c */
+extern int __init init_mmiotrace(void);
+extern void enable_mmiotrace(void);
+extern void disable_mmiotrace(void);
+extern void mmio_trace_record(u32 type, unsigned long addr, unsigned long arg);
+
 #endif /* __KERNEL__ */