v4.19.13 snapshot.
diff --git a/include/linux/kcov.h b/include/linux/kcov.h
new file mode 100644
index 0000000..b76a180
--- /dev/null
+++ b/include/linux/kcov.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KCOV_H
+#define _LINUX_KCOV_H
+
+#include <uapi/linux/kcov.h>
+
+struct task_struct;
+
+#ifdef CONFIG_KCOV
+
+enum kcov_mode {
+	/* Coverage collection is not enabled yet. */
+	KCOV_MODE_DISABLED = 0,
+	/* KCOV was initialized, but tracing mode hasn't been chosen yet. */
+	KCOV_MODE_INIT = 1,
+	/*
+	 * Tracing coverage collection mode.
+	 * Covered PCs are collected in a per-task buffer.
+	 */
+	KCOV_MODE_TRACE_PC = 2,
+	/* Collecting comparison operands mode. */
+	KCOV_MODE_TRACE_CMP = 3,
+};
+
+#define KCOV_IN_CTXSW	(1 << 30)
+
+void kcov_task_init(struct task_struct *t);
+void kcov_task_exit(struct task_struct *t);
+
+#define kcov_prepare_switch(t)			\
+do {						\
+	(t)->kcov_mode |= KCOV_IN_CTXSW;	\
+} while (0)
+
+#define kcov_finish_switch(t)			\
+do {						\
+	(t)->kcov_mode &= ~KCOV_IN_CTXSW;	\
+} while (0)
+
+#else
+
+static inline void kcov_task_init(struct task_struct *t) {}
+static inline void kcov_task_exit(struct task_struct *t) {}
+static inline void kcov_prepare_switch(struct task_struct *t) {}
+static inline void kcov_finish_switch(struct task_struct *t) {}
+
+#endif /* CONFIG_KCOV */
+#endif /* _LINUX_KCOV_H */