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

2 files changed, 25 insertions, 11 deletions

diff --git a/nuttx/sched/pthread_create.c b/nuttx/sched/pthread_create.c
index 346f51411..3fcb7eea1 100644
--- a/nuttx/sched/pthread_create.c
+++ b/nuttx/sched/pthread_create.c
@@ -174,9 +174,7 @@ static void pthread_start(void)
 
   DEBUGASSERT(group && pjoin);
 
-  /* Sucessfully spawned, add the pjoin to our data set.
-   * Don't re-enable pre-emption until this is done.
-   */
+  /* Sucessfully spawned, add the pjoin to our data set. */
 
   (void)pthread_takesemaphore(&group->tg_joinsem);
   pthread_addjoininfo(group, pjoin);
@@ -187,10 +185,7 @@ static void pthread_start(void)
   pjoin->started = true;
   (void)pthread_givesemaphore(&pjoin->data_sem);
 
-  /* Pass control to the thread entry point.  The argument is
-   * argv[1].  argv[0] (the thread name) and argv[2-4] are not made
-   * available to the pthread.
-   */
+  /* Pass control to the thread entry point. */
 
   exit_status = (*ptcb->cmn.entry.pthread)(ptcb->arg);
 
diff --git a/nuttx/sched/task_start.c b/nuttx/sched/task_start.c
index 8e012b515..e9667d486 100644
--- a/nuttx/sched/task_start.c
+++ b/nuttx/sched/task_start.c
@@ -43,10 +43,13 @@
 #include <sched.h>
 #include <debug.h>
 
+#include <nuttx/arch.h>
+#include <nuttx/sched.h>
+
 #include "os_internal.h"
 
 /****************************************************************************
- * Definitions
+ * Pre-processor Definitions
  ****************************************************************************/
 
 /****************************************************************************
@@ -92,6 +95,7 @@
 void task_start(void)
 {
   FAR struct task_tcb_s *tcb = (FAR struct task_tcb_s*)g_readytorun.head;
+  int exitcode;
   int argc;
 
   DEBUGASSERT((tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD);
@@ -117,9 +121,24 @@ void task_start(void)
         }
     }
 
-  /* Call the 'main' entry point passing argc and argv.  If/when
-   * the task returns.
+  /* Call the 'main' entry point passing argc and argv.  In the kernel build
+   * this has to be handled differently if we are starting a user-space task;
+   * we have to switch to user-mode before calling the task.
    */
 
-  exit(tcb->cmn.entry.main(argc, tcb->argv));
+#ifdef CONFIG_NUTTX_KERNEL
+  if ((tcb->cmn.flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
+    {
+      up_task_start(tcb->cmn.entry.main, argc, tcb->argv);
+      exitcode = EXIT_FAILURE; /* Should not get here */
+    }
+  else
+#endif
+    {
+      exitcode = tcb->cmn.entry.main(argc, tcb->argv);
+    }
+
+  /* Call exit() if/when the task returns */
+
+  exit(exitcode);
 }