sync branch rt-smart. (#6641)

* Synchronize the code of the rt mart branch to the master branch.
  * TTY device
  * Add lwP code from rt-smart
  * Add vnode in DFS, but DFS will be re-write for rt-smart
  * There are three libcpu for rt-smart:
    * arm/cortex-a, arm/aarch64
    * riscv64

Co-authored-by: Rbb666 <zhangbingru@rt-thread.com>
Co-authored-by: zhkag <zhkag@foxmail.com>

components/lwp/syscall_data.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2006-2022, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2022-11-10     RT-Thread    The first version
+ */
+#ifndef __SYSCALL_DATA_H__
+#define __SYSCALL_DATA_H__
+
+#include <rtthread.h>
+
+/**
+ * @brief signature for syscall, used to locate syscall metadata.
+ *
+ * We don't allocate an exclusive section in ELF like Linux do
+ * to avoid initializing necessary data by iterating that section,
+ * which increases system booting time. We signature a pointer
+ * just below each syscall entry in syscall table to make it
+ * easy to locate every syscall's metadata by using syscall id.
+ *
+ * TODO Currently this adds a dummy pointer to syscall name.
+ * After adding metadata of every syscalls in front of their definition,
+ * this should be replaced by a pointer to that structure
+ */
+#define SYSCALL_SIGN(func) \
+    (void *)func,          \
+        RT_STRINGIFY(func)
+
+#endif /* __SYSCALL_DATA_H__ */