Introduce struct ksw_ctx to enable lockless per-task state
tracking. This is required because KStackWatch operates in NMI context
(via kprobe handler) where traditional locking is unsafe.

Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
---
 include/linux/kstackwatch_types.h | 14 ++++++++++++++
 include/linux/sched.h             |  5 +++++
 2 files changed, 19 insertions(+)
 create mode 100644 include/linux/kstackwatch_types.h

diff --git a/include/linux/kstackwatch_types.h b/include/linux/kstackwatch_types.h
new file mode 100644
index 000000000000..8c4e9b0f0c6a
--- /dev/null
+++ b/include/linux/kstackwatch_types.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KSTACKWATCH_TYPES_H
+#define _LINUX_KSTACKWATCH_TYPES_H
+#include <linux/types.h>
+
+struct ksw_watchpoint;
+struct ksw_ctx {
+	struct ksw_watchpoint *wp;
+	ulong sp;
+	u16 depth;
+	u16 generation;
+};
+
+#endif /* _LINUX_KSTACKWATCH_TYPES_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b469878de25c..db49325428b3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -22,6 +22,7 @@
 #include <linux/sem_types.h>
 #include <linux/shm.h>
 #include <linux/kmsan_types.h>
+#include <linux/kstackwatch_types.h>
 #include <linux/mutex_types.h>
 #include <linux/plist_types.h>
 #include <linux/hrtimer_types.h>
@@ -1487,6 +1488,10 @@ struct task_struct {
 	struct kmsan_ctx		kmsan_ctx;
 #endif
 
+#if IS_ENABLED(CONFIG_KSTACKWATCH)
+	struct ksw_ctx		ksw_ctx;
+#endif
+
 #if IS_ENABLED(CONFIG_KUNIT)
 	struct kunit			*kunit_test;
 #endif
-- 
2.43.0