添加rtthread相关代码

riscv/rtthread/components/lwp/lwp_shm.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2006-2020, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2019-10-12     Jesven       first version
+ */
+#ifndef  __LWP_SHM_H__
+#define  __LWP_SHM_H__
+
+#include <lwp_avl.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int lwp_shmget(size_t key, size_t size, int create);
+int lwp_shmrm(int id);
+void* lwp_shmat(int id, void* shm_vaddr);
+int lwp_shmdt(void* shm_vaddr);
+void *lwp_shminfo(int id);
+int lwp_shm_ref_inc(struct rt_lwp *lwp, void *shm_vaddr);
+int lwp_shm_ref_dec(struct rt_lwp *lwp, void *shm_vaddr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /*__LWP_SHM_H__*/