v4.19.13 snapshot.
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
new file mode 100644
index 0000000..f128dc3
--- /dev/null
+++ b/include/linux/context_tracking_state.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
+#define _LINUX_CONTEXT_TRACKING_STATE_H
+
+#include <linux/percpu.h>
+#include <linux/static_key.h>
+
+struct context_tracking {
+ /*
+ * When active is false, probes are unset in order
+ * to minimize overhead: TIF flags are cleared
+ * and calls to user_enter/exit are ignored. This
+ * may be further optimized using static keys.
+ */
+ bool active;
+ int recursion;
+ enum ctx_state {
+ CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
+ CONTEXT_KERNEL = 0,
+ CONTEXT_USER,
+ CONTEXT_GUEST,
+ } state;
+};
+
+#ifdef CONFIG_CONTEXT_TRACKING
+extern struct static_key_false context_tracking_enabled;
+DECLARE_PER_CPU(struct context_tracking, context_tracking);
+
+static inline bool context_tracking_is_enabled(void)
+{
+ return static_branch_unlikely(&context_tracking_enabled);
+}
+
+static inline bool context_tracking_cpu_is_enabled(void)
+{
+ return __this_cpu_read(context_tracking.active);
+}
+
+static inline bool context_tracking_in_user(void)
+{
+ return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
+}
+#else
+static inline bool context_tracking_in_user(void) { return false; }
+static inline bool context_tracking_active(void) { return false; }
+static inline bool context_tracking_is_enabled(void) { return false; }
+static inline bool context_tracking_cpu_is_enabled(void) { return false; }
+#endif /* CONFIG_CONTEXT_TRACKING */
+
+#endif