kernel: thread: Move out the function _thread_entry() to lib

The _thread_entry() is not really a part of the kernel but a part of
the zephyr's C runtime support library. Hence moving just the
function to lib/thread_entry.c

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>

kernel/thread.c

@@ -208,37 +208,6 @@ void _check_stack_sentinel(void)
 }
 #endif
 
-/*
- * Common thread entry point function (used by all threads)
- *
- * This routine invokes the actual thread entry point function and passes
- * it three arguments. It also handles graceful termination of the thread
- * if the entry point function ever returns.
- *
- * This routine does not return, and is marked as such so the compiler won't
- * generate preamble code that is only used by functions that actually return.
- */
-FUNC_NORETURN void _thread_entry(k_thread_entry_t entry,
-				 void *p1, void *p2, void *p3)
-{
-	entry(p1, p2, p3);
-
-#ifdef CONFIG_MULTITHREADING
-	k_thread_abort(k_current_get());
-#else
-	for (;;) {
-		k_cpu_idle();
-	}
-#endif
-
-	/*
-	 * Compiler can't tell that k_thread_abort() won't return and issues a
-	 * warning unless we tell it that control never gets this far.
-	 */
-
-	CODE_UNREACHABLE;
-}
-
 #ifdef CONFIG_MULTITHREADING
 void _impl_k_thread_start(struct k_thread *thread)
 {

lib/CMakeLists.txt

@@ -1,3 +1,4 @@
+zephyr_sources(thread_entry.c)
 add_subdirectory(crc)
 add_subdirectory_ifdef(CONFIG_JSON_LIBRARY          json)
 if(NOT CONFIG_NATIVE_APPLICATION)

lib/thread_entry.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Thread entry
+ *
+ * This file provides the common thread entry function
+ */
+
+#include <kernel.h>
+
+/*
+ * Common thread entry point function (used by all threads)
+ *
+ * This routine invokes the actual thread entry point function and passes
+ * it three arguments. It also handles graceful termination of the thread
+ * if the entry point function ever returns.
+ *
+ * This routine does not return, and is marked as such so the compiler won't
+ * generate preamble code that is only used by functions that actually return.
+ */
+FUNC_NORETURN void _thread_entry(k_thread_entry_t entry,
+				 void *p1, void *p2, void *p3)
+{
+	entry(p1, p2, p3);
+
+#ifdef CONFIG_MULTITHREADING
+	k_thread_abort(k_current_get());
+#else
+	for (;;) {
+		k_cpu_idle();
+	}
+#endif
+
+	/*
+	 * Compiler can't tell that k_thread_abort() won't return and issues a
+	 * warning unless we tell it that control never gets this far.
+	 */
+
+	CODE_UNREACHABLE;
+}