score: Delete _Thread_BSP_context

Do not return to BSP context in the exit() shutdown path.  This makes it
possible to re-use the initialization stack.  It can be used for the
interrupt stack for example.  On targets with a small RAM this is a
considerable benefit.

This change eliminates also some special cases and simplifies the code.

Delete _Thread_Set_global_exit_status(),
_Thread_Get_global_exit_status() and _Thread_Stop_multitasking().

8 files changed, 41 insertions, 159 deletions

diff --git a/cpukit/sapi/src/exinit.c b/cpukit/sapi/src/exinit.c
index 10c1559936..e8b009ba60 100644
--- a/cpukit/sapi/src/exinit.c
+++ b/cpukit/sapi/src/exinit.c
@@ -33,7 +33,6 @@
 #include <rtems/config.h>
 #include <rtems/debug.h>
 #include <rtems/extensionimpl.h>
-#include <rtems/fatal.h>
 #include <rtems/init.h>
 #include <rtems/io.h>
 #include <rtems/score/sysstate.h>
@@ -215,25 +214,20 @@ void rtems_initialize_device_drivers(void)
 
 void rtems_initialize_start_multitasking(void)
 {
-  uint32_t status;
-
   _System_state_Set( SYSTEM_STATE_UP );
 
 #if defined(RTEMS_SMP)
   _SMP_Request_other_cores_to_perform_first_context_switch();
 #endif
 
-  _Thread_Start_multitasking( &_Thread_BSP_context );
+  _Thread_Start_multitasking();
 
   /*******************************************************************
    *******************************************************************
    *******************************************************************
    ******                 APPLICATION RUNS HERE                 ******
-   ******            RETURNS WHEN SYSTEM IS SHUT DOWN           ******
+   ******              THE FUNCTION NEVER RETURNS               ******
    *******************************************************************
    *******************************************************************
    *******************************************************************/
-
-  status = _Thread_Get_global_exit_status();
-  rtems_fatal( RTEMS_FATAL_SOURCE_EXIT, status );
 }
diff --git a/cpukit/sapi/src/exshutdown.c b/cpukit/sapi/src/exshutdown.c
index 44c5a09084..41ee537e44 100644
--- a/cpukit/sapi/src/exshutdown.c
+++ b/cpukit/sapi/src/exshutdown.c
@@ -15,47 +15,37 @@
 
 #include <rtems/init.h>
 #include <rtems/score/sysstate.h>
-#include <rtems/score/threadimpl.h>
 #include <rtems/score/interr.h>
 
 #if defined(RTEMS_SMP)
   #include <rtems/score/smp.h>
 #endif
 
-/*
- *  rtems_shutdown_executive
- *
- *  This kernel routine shutdowns the executive.  It halts multitasking
- *  and returns control to the application execution "thread" which
- *  initialially invoked the rtems_initialize_executive directive.
- *
- *  Input parameters:   NONE
- *
- *  Output parameters:  NONE
- */
-
-void rtems_shutdown_executive(
-   uint32_t   result
-)
+void rtems_shutdown_executive( uint32_t result )
 {
+  Internal_errors_Source  source;
+  bool                    is_internal;
+  Internal_errors_t       code;
+
   if ( _System_state_Is_up( _System_state_Get() ) ) {
     #if defined(RTEMS_SMP)
       _SMP_Request_other_cores_to_shutdown();
     #endif
 
-    _Thread_Set_global_exit_status( result );
-    _Thread_Stop_multitasking();
-
-    /*******************************************************************
-     *******************************************************************
-     ******     RETURN TO RTEMS_INITIALIZE_START_MULTITASKING()   ******
-     ******                 AND THEN TO BOOT_CARD()               ******
-     *******************************************************************
-     *******************************************************************/
+    source      = RTEMS_FATAL_SOURCE_EXIT;
+    is_internal = false;
+    code        = result;
+  } else {
+    source      = INTERNAL_ERROR_CORE;
+    is_internal = true;
+    code        = INTERNAL_ERROR_SHUTDOWN_WHEN_NOT_UP;
   }
-  _Internal_error_Occurred(
-    INTERNAL_ERROR_CORE,
-    true,
-    INTERNAL_ERROR_SHUTDOWN_WHEN_NOT_UP
-  );
+
+  _Internal_error_Occurred( source, is_internal, code );
+
+  /***************************************************************
+   ***************************************************************
+   *   SYSTEM SHUTS DOWN!!!  WE DO NOT RETURN TO THIS POINT!!!   *
+   ***************************************************************
+   ***************************************************************/
 }
diff --git a/cpukit/score/cpu/arm/armv7m-multitasking-start-stop.c b/cpukit/score/cpu/arm/armv7m-multitasking-start-stop.c
index f3e96e343c..864bb53379 100644
--- a/cpukit/score/cpu/arm/armv7m-multitasking-start-stop.c
+++ b/cpukit/score/cpu/arm/armv7m-multitasking-start-stop.c
@@ -1,14 +1,14 @@
 /**
  * @file
  *
- * @brief ARMV7M Start and Stop Multitasking
+ * @brief ARMV7M Start Multitasking
  */
 
 /*
- * Copyright (c) 2011 Sebastian Huber.  All rights reserved.
+ * Copyright (c) 2011-2014 Sebastian Huber.  All rights reserved.
  *
  *  embedded brains GmbH
- *  Obere Lagerstr. 30
+ *  Dornierstr. 4
  *  82178 Puchheim
  *  Germany
  *  <rtems@embedded-brains.de>
@@ -27,18 +27,14 @@
 #ifdef ARM_MULTILIB_ARCH_V7M
 
 void __attribute__((naked)) _ARMV7M_Start_multitasking(
-  Context_Control *bsp,
   Context_Control *heir
 )
 {
   __asm__ volatile (
-    /* Store BSP context */
-    "stm r0, {r4-r11, lr}\n"
-    "str sp, [r0, %[spctxoff]]\n"
     /* Restore heir context */
-    "ldr r2, [r1, %[spctxoff]]\n"
+    "ldr r2, [r0, %[spctxoff]]\n"
     "msr psp, r2\n"
-    "ldm r1, {r4-r11, lr}\n"
+    "ldm r0, {r4-r11, lr}\n"
     /* Enable process stack pointer (PSP) */
     "mrs r2, control\n"
     "orr r2, #0x2\n"
@@ -50,26 +46,4 @@ void __attribute__((naked)) _ARMV7M_Start_multitasking(
   );
 }
 
-void __attribute__((naked)) _ARMV7M_Stop_multitasking( Context_Control *bsp )
-{
-  __asm__ volatile (
-    /* Disable interrupts */
-    "mov r2, #0x80\n"
-    "msr basepri_max, r2\n"
-    /* Restore BSP context */
-    "ldr r2, [r0, %[spctxoff]]\n"
-    "msr msp, r2\n"
-    "ldm r0, {r4-r11, lr}\n"
-    /* Disable process stack pointer (PSP) */
-    "mrs r2, control\n"
-    "bic r2, #0x2\n"
-    "msr control, r2\n"
-    /* Return to BSP */
-    "bx lr\n"
-    :
-    : [spctxoff] "J" (offsetof(Context_Control, register_sp))
-  );
-  __builtin_unreachable();
-}
-
 #endif /* ARM_MULTILIB_ARCH_V7M */
diff --git a/cpukit/score/cpu/arm/rtems/score/cpu.h b/cpukit/score/cpu/arm/rtems/score/cpu.h
index d7c54ade3a..a0c6b41a58 100644
--- a/cpukit/score/cpu/arm/rtems/score/cpu.h
+++ b/cpukit/score/cpu/arm/rtems/score/cpu.h
@@ -458,11 +458,8 @@ void _CPU_Context_restore( Context_Control *new_context )
   RTEMS_COMPILER_NO_RETURN_ATTRIBUTE;
 
 #if defined(ARM_MULTILIB_ARCH_V7M)
-  void _ARMV7M_Start_multitasking( Context_Control *bsp, Context_Control *heir );
-  void _ARMV7M_Stop_multitasking( Context_Control *bsp )
-    RTEMS_COMPILER_NO_RETURN_ATTRIBUTE;
+  void _ARMV7M_Start_multitasking( Context_Control *heir );
   #define _CPU_Start_multitasking _ARMV7M_Start_multitasking
-  #define _CPU_Stop_multitasking _ARMV7M_Stop_multitasking
 #endif
 
 void _CPU_Context_volatile_clobber( uintptr_t pattern );
diff --git a/cpukit/score/include/rtems/score/threadimpl.h b/cpukit/score/include/rtems/score/threadimpl.h
index 4f4fbc7f62..7c1d2a7d2c 100644
--- a/cpukit/score/include/rtems/score/threadimpl.h
+++ b/cpukit/score/include/rtems/score/threadimpl.h
@@ -20,6 +20,7 @@
 #define _RTEMS_SCORE_THREADIMPL_H
 
 #include <rtems/score/thread.h>
+#include <rtems/score/interr.h>
 #include <rtems/score/isr.h>
 #include <rtems/score/objectimpl.h>
 #include <rtems/score/statesimpl.h>
@@ -54,15 +55,6 @@ SCORE_EXTERN void *rtems_ada_self;
 SCORE_EXTERN Objects_Information _Thread_Internal_information;
 
 /**
- *  The following context area contains the context of the "thread"
- *  which invoked the start multitasking routine.  This context is
- *  restored as the last action of the stop multitasking routine.  Thus
- *  control of the processor can be returned to the environment
- *  which initiated the system.
- */
-SCORE_EXTERN Context_Control _Thread_BSP_context;
-
-/**
  *  The following holds how many user extensions are in the system.  This
  *  is used to determine how many user extension data areas to allocate
  *  per thread.
@@ -114,13 +106,8 @@ void _Thread_Create_idle(void);
  *  This routine initiates multitasking.  It is invoked only as
  *  part of initialization and its invocation is the last act of
  *  the non-multitasking part of the system initialization.
- *
- *
- *  - INTERRUPT LATENCY:
- *    + ready chain
- *    + select heir
  */
-void _Thread_Start_multitasking( Context_Control *context );
+void _Thread_Start_multitasking( void ) RTEMS_COMPILER_NO_RETURN_ATTRIBUTE;
 
 /**
  *  @brief Allocate the requested stack space for the thread.
@@ -446,36 +433,6 @@ void _Thread_blocking_operation_Cancel(
 );
 
 /**
- * This routine halts multitasking and returns control to
- * the "thread" (i.e. the BSP) which initially invoked the
- * routine which initialized the system.
- */
-
-RTEMS_INLINE_ROUTINE void _Thread_Stop_multitasking( void )
-{
-#if defined(_CPU_Stop_multitasking)
-  _CPU_Stop_multitasking( &_Thread_BSP_context );
-#else
-  /*
-   *  This may look a bit of an odd but _Context_Restart_self is just
-   *  a very careful restore of a specific context which ensures that
-   *  if we were running within the same context, it would work.
-   *
-   *  And we will not return to this thread, so there is no point of
-   *  saving the context.
-   */
-  _Context_Restart_self( &_Thread_BSP_context );
-#endif
-
-  /***************************************************************
-   ***************************************************************
-   *   SYSTEM SHUTS DOWN!!!  WE DO NOT RETURN TO THIS POINT!!!   *
-   ***************************************************************
-   ***************************************************************
-   */
-}
-
-/**
  * This function returns true if the_thread is the currently executing
  * thread, and false otherwise.
  */
@@ -630,24 +587,6 @@ RTEMS_INLINE_ROUTINE void _Thread_Internal_free (
   _Objects_Free( &_Thread_Internal_information, &the_task->Object );
 }
 
-RTEMS_INLINE_ROUTINE void _Thread_Set_global_exit_status(
-  uint32_t exit_status
-)
-{
-  Thread_Control *idle = (Thread_Control *)
-    _Thread_Internal_information.local_table[ 1 ];
-
-  idle->Wait.return_code = exit_status;
-}
-
-RTEMS_INLINE_ROUTINE uint32_t _Thread_Get_global_exit_status( void )
-{
-  const Thread_Control *idle = (const Thread_Control *)
-    _Thread_Internal_information.local_table[ 1 ];
-
-  return idle->Wait.return_code;
-}
-
 RTEMS_INLINE_ROUTINE void _Thread_Signal_notification( Thread_Control *thread )
 {
   if ( _ISR_Is_in_progress() && _Thread_Is_executing( thread ) ) {
diff --git a/cpukit/score/src/smp.c b/cpukit/score/src/smp.c
index 2f8a488474..df1c6d312a 100644
--- a/cpukit/score/src/smp.c
+++ b/cpukit/score/src/smp.c
@@ -40,7 +40,7 @@ void rtems_smp_secondary_cpu_initialize( void )
 
   _Per_CPU_Wait_for_state( self_cpu, PER_CPU_STATE_BEGIN_MULTITASKING );
 
-  _Thread_Start_multitasking( NULL );
+  _Thread_Start_multitasking();
 }
 
 void rtems_smp_process_interrupt( void )
diff --git a/cpukit/score/src/threadstartmultitasking.c b/cpukit/score/src/threadstartmultitasking.c
index 52337ab558..b05ccb48c3 100644
--- a/cpukit/score/src/threadstartmultitasking.c
+++ b/cpukit/score/src/threadstartmultitasking.c
@@ -20,7 +20,7 @@
 
 #include <rtems/score/threadimpl.h>
 
-void _Thread_Start_multitasking( Context_Control *context )
+void _Thread_Start_multitasking( void )
 {
   Per_CPU_Control *self_cpu = _Per_CPU_Get();
   Thread_Control  *heir = self_cpu->heir;
@@ -28,7 +28,13 @@ void _Thread_Start_multitasking( Context_Control *context )
 #if defined(RTEMS_SMP)
   _Per_CPU_Change_state( self_cpu, PER_CPU_STATE_UP );
 
+  /*
+   * Threads begin execution in the _Thread_Handler() function.   This
+   * function will set the thread dispatch disable level to zero and calls
+   * _Per_CPU_Release().
+   */
   _Per_CPU_Acquire( self_cpu );
+  self_cpu->thread_dispatch_disable_level = 1;
 
   self_cpu->executing->is_executing = false;
   heir->is_executing = true;
@@ -59,26 +65,9 @@ void _Thread_Start_multitasking( Context_Control *context )
      _Context_Restore_fp( &heir->fp_context );
 #endif
 
-#if defined(RTEMS_SMP)
-  if ( context != NULL ) {
-#endif
-
 #if defined(_CPU_Start_multitasking)
-    _CPU_Start_multitasking( context, &heir->Registers );
+    _CPU_Start_multitasking( &heir->Registers );
 #else
-    _Context_Switch( context, &heir->Registers );
-#endif
-
-#if defined(RTEMS_SMP)
-  } else {
-    /*
-     * Threads begin execution in the _Thread_Handler() function.   This
-     * function will set the thread dispatch disable level to zero and calls
-     * _Per_CPU_Release().
-     */
-    self_cpu->thread_dispatch_disable_level = 1;
-
-    _CPU_Context_restore( &heir->Registers );
-  }
+    _CPU_Context_Restart_self( &heir->Registers );
 #endif
 }
diff --git a/testsuites/sptests/spsize/size.c b/testsuites/sptests/spsize/size.c
index f204c05781..5b3cefec61 100644
--- a/testsuites/sptests/spsize/size.c
+++ b/testsuites/sptests/spsize/size.c
@@ -385,8 +385,7 @@ uninitialized =
 
 /*tasksimpl.h*/ (sizeof _RTEMS_tasks_Information)         +
 
-/*thread.h*/    (sizeof _Thread_BSP_context)              +
-                (sizeof _Thread_Dispatch_disable_level)   +
+/*thread.h*/    (sizeof _Thread_Dispatch_disable_level)   +
                 (sizeof _Thread_Maximum_extensions)       +
                 (sizeof _Thread_Ticks_per_timeslice)      +
                 (sizeof _Thread_Executing)                +