score: Simplify thread control initialization

The thread control block contains fields that point to application
configuration dependent memory areas, like the scheduler information,
the API control blocks, the user extension context table, the RTEMS
notepads and the Newlib re-entrancy support.  Account for these areas in
the configuration and avoid extra workspace allocations for these areas.

This helps also to avoid heap fragementation and reduces the per thread
memory due to a reduced heap allocation overhead.

1 files changed, 24 insertions, 41 deletions

diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 6864df58e9..153c1d0b13 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -42,15 +42,15 @@ bool _Thread_Initialize(
   Objects_Name                          name
 )
 {
-  size_t     actual_stack_size = 0;
-  void      *stack = NULL;
+  size_t                   actual_stack_size = 0;
+  void                    *stack = NULL;
   #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
-    void    *fp_area;
+    void                  *fp_area = NULL;
   #endif
-  void      *sched = NULL;
-  void      *extensions_area;
-  bool       extension_status;
-  int        i;
+  bool                     extension_status;
+  size_t                   i;
+  bool                     scheduler_allocated = false;
+  const Scheduler_Control *scheduler;
 
   /*
    * Do not use _TLS_Size here since this will lead GCC to assume that this
@@ -64,6 +64,13 @@ bool _Thread_Initialize(
   }
 #endif
 
+  for ( i = 0 ; i < _Thread_Control_add_on_count ; ++i ) {
+    const Thread_Control_add_on *add_on = &_Thread_Control_add_ons[ i ];
+
+    *(void **) ( (char *) the_thread + add_on->destination_offset ) =
+      (char *) the_thread + add_on->source_offset;
+  }
+
   /*
    *  Initialize the Ada self pointer
    */
@@ -71,20 +78,8 @@ bool _Thread_Initialize(
     the_thread->rtems_ada_self = NULL;
   #endif
 
-  /*
-   *  Zero out all the allocated memory fields
-   */
-  for ( i=0 ; i <= THREAD_API_LAST ; i++ )
-    the_thread->API_Extensions[i] = NULL;
-
-  extensions_area = NULL;
-  the_thread->libc_reent = NULL;
   the_thread->Start.tls_area = NULL;
 
-  #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
-    fp_area = NULL;
-  #endif
-
   /*
    *  Allocate and Initialize the stack for this thread.
    */
@@ -153,18 +148,6 @@ bool _Thread_Initialize(
   #endif
 
   /*
-   *  Allocate the extensions area for this thread
-   */
-  if ( rtems_configuration_get_maximum_extensions() ) {
-    extensions_area = _Workspace_Allocate(
-      (rtems_configuration_get_maximum_extensions() + 1) * sizeof( void * )
-    );
-    if ( !extensions_area )
-      goto failed;
-  }
-  the_thread->extensions = (void **) extensions_area;
-
-  /*
    * Clear the extensions area so extension users can determine
    * if they are linked to the thread. An extension user may
    * create the extension long after tasks have been created
@@ -215,9 +198,13 @@ bool _Thread_Initialize(
   the_thread->resource_count          = 0;
   the_thread->real_priority           = priority;
   the_thread->Start.initial_priority  = priority;
-  sched =_Scheduler_Allocate( _Scheduler_Get( the_thread ), the_thread );
-  if ( !sched )
+
+  scheduler = _Scheduler_Get( _Thread_Get_executing() );
+  scheduler_allocated = _Scheduler_Allocate( scheduler, the_thread );
+  if ( !scheduler_allocated ) {
     goto failed;
+  }
+
   _Thread_Set_priority( the_thread, priority );
 
   /*
@@ -260,21 +247,17 @@ bool _Thread_Initialize(
     return true;
 
 failed:
-  _Workspace_Free( the_thread->Start.tls_area );
-
-  _Workspace_Free( the_thread->libc_reent );
 
-  for ( i=0 ; i <= THREAD_API_LAST ; i++ )
-    _Workspace_Free( the_thread->API_Extensions[i] );
+  if ( scheduler_allocated ) {
+    _Scheduler_Free( scheduler, the_thread );
+  }
 
-  _Workspace_Free( extensions_area );
+  _Workspace_Free( the_thread->Start.tls_area );
 
   #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
     _Workspace_Free( fp_area );
   #endif
 
-   _Workspace_Free( sched );
-
    _Thread_Stack_Free( the_thread );
   return false;
 }