Switch to user-mode before starting a new task

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5742 42af7a65-404d-4744-a932-0658087f49c3

libc/sched/Make.defs

@@ -37,6 +37,10 @@
 
 CSRCS += sched_getprioritymax.c sched_getprioritymin.c
 
+ifeq ($(CONFIG_NUTTX_KERNEL),y)
+CSRCS += task_startup.c
+endif
+
 # Add the sched directory to the build
 
 DEPPATH += --dep-path sched

libc/sched/task_startup.c

@@ -0,0 +1,104 @@
+/****************************************************************************
+ * libc/sched/task_startup.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include <nuttx/sched.h>
+
+#if defined(CONFIG_NUTTX_KERNEL) && !defined(__KERNEL__)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: task_startup
+ *
+ * Description:
+ *   This function is the user-space, task startup function.  It is called
+ *   from up_task_start() in user-mode.
+ *
+ * Inputs:
+ *   entrypt - The user-space address of the task entry point
+ *   argc and argv - Standard arguments for the task entry point
+ *
+ * Return:
+ *   None.  This function does not return.
+ *
+ ****************************************************************************/
+
+void task_startup(main_t entrypt, int argc, FAR char *argv[])
+{
+  DEBUGASSERT(entrypt);
+
+  /* Call the 'main' entry point passing argc and argv, calling exit()
+   * if/when the task returns.
+   */
+
+  exit(entrypt(argc, argv));
+}
+
+#endif /* CONFIG_NUTTX_KERNEL && !__KERNEL__ */