1 files changed, 81 insertions, 0 deletions
diff --git a/include/linux/unwind_deferred.h b/include/linux/unwind_deferred.h
new file mode 100644
index 000000000000..26122d00708a
--- /dev/null
+++ b/include/linux/unwind_deferred.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_UNWIND_USER_DEFERRED_H
+#define _LINUX_UNWIND_USER_DEFERRED_H
+
+#include <linux/task_work.h>
+#include <linux/unwind_user.h>
+#include <linux/unwind_deferred_types.h>
+
+struct unwind_work;
+
+typedef void (*unwind_callback_t)(struct unwind_work *work, struct unwind_stacktrace *trace, u64 cookie);
+
+struct unwind_work {
+	struct list_head		list;
+	unwind_callback_t		func;
+	int				bit;
+};
+
+#ifdef CONFIG_UNWIND_USER
+
+enum {
+	UNWIND_PENDING_BIT = 0,
+	UNWIND_USED_BIT,
+};
+
+enum {
+	UNWIND_PENDING		= BIT(UNWIND_PENDING_BIT),
+
+	/* Set if the unwinding was used (directly or deferred) */
+	UNWIND_USED		= BIT(UNWIND_USED_BIT)
+};
+
+void unwind_task_init(struct task_struct *task);
+void unwind_task_free(struct task_struct *task);
+
+int unwind_user_faultable(struct unwind_stacktrace *trace);
+
+int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func);
+int unwind_deferred_request(struct unwind_work *work, u64 *cookie);
+void unwind_deferred_cancel(struct unwind_work *work);
+
+void unwind_deferred_task_exit(struct task_struct *task);
+
+static __always_inline void unwind_reset_info(void)
+{
+	struct unwind_task_info *info = &current->unwind_info;
+	unsigned long bits;
+
+	/* Was there any unwinding? */
+	if (unlikely(info->unwind_mask)) {
+		bits = info->unwind_mask;
+		do {
+			/* Is a task_work going to run again before going back */
+			if (bits & UNWIND_PENDING)
+				return;
+		} while (!try_cmpxchg(&info->unwind_mask, &bits, 0UL));
+		current->unwind_info.id.id = 0;
+
+		if (unlikely(info->cache)) {
+			info->cache->nr_entries = 0;
+			info->cache->unwind_completed = 0;
+		}
+	}
+}
+
+#else /* !CONFIG_UNWIND_USER */
+
+static inline void unwind_task_init(struct task_struct *task) {}
+static inline void unwind_task_free(struct task_struct *task) {}
+
+static inline int unwind_user_faultable(struct unwind_stacktrace *trace) { return -ENOSYS; }
+static inline int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func) { return -ENOSYS; }
+static inline int unwind_deferred_request(struct unwind_work *work, u64 *timestamp) { return -ENOSYS; }
+static inline void unwind_deferred_cancel(struct unwind_work *work) {}
+
+static inline void unwind_deferred_task_exit(struct task_struct *task) {}
+static inline void unwind_reset_info(void) {}
+
+#endif /* !CONFIG_UNWIND_USER */
+
+#endif /* _LINUX_UNWIND_USER_DEFERRED_H */