diff --git a/libc/kernel/uapi/linux/kcov.h b/libc/kernel/uapi/linux/kcov.h
index 9688c38..40f9912 100644
--- a/libc/kernel/uapi/linux/kcov.h
+++ b/libc/kernel/uapi/linux/kcov.h
@@ -22,4 +22,11 @@
 #define KCOV_INIT_TRACE _IOR('c', 1, unsigned long)
 #define KCOV_ENABLE _IO('c', 100)
 #define KCOV_DISABLE _IO('c', 101)
+enum {
+  KCOV_TRACE_PC = 0,
+  KCOV_TRACE_CMP = 1,
+};
+#define KCOV_CMP_CONST (1 << 0)
+#define KCOV_CMP_SIZE(n) ((n) << 1)
+#define KCOV_CMP_MASK KCOV_CMP_SIZE(3)
 #endif