score: Simplify thread stack allocation

Remove superfluous Thread_Control::Start::stack member.

Update #3835.

cpukit/include/rtems/score/stackimpl.h

@@ -105,6 +105,16 @@ RTEMS_INLINE_ROUTINE size_t _Stack_Ensure_minimum (
   return _Stack_Minimum();
 }
 
+/**
+ * @brief Allocate the requested stack space.
+ *
+ * @param stack_size The stack space that is requested.
+ *
+ * @retval stack_area The allocated stack area.
+ * @retval NULL The allocation failed.
+ */
+void *_Stack_Allocate( size_t stack_size );
+
 /** @} */
 
 #ifdef __cplusplus

cpukit/include/rtems/score/thread.h

@@ -209,8 +209,6 @@ typedef struct {
     /** This field is the initial FP context area address. */
     Context_Control_fp                  *fp_context;
   #endif
-  /** This field is the initial stack area address. */
-  void                                *stack;
   /** The thread-local storage (TLS) area */
   void                                *tls_area;
 } Thread_Start_information;

cpukit/include/rtems/score/threadimpl.h

@@ -124,23 +124,6 @@ void _Thread_Create_idle(void);
  */
 void _Thread_Start_multitasking( void ) RTEMS_NO_RETURN;
 
-/**
- * @brief Allocates the requested stack space for the thread.
- *
- * Allocate the requested stack space for the thread.
- * Set the Start.stack field to the address of the stack.
- *
- * @param[out] the_thread The thread where the stack space is requested.
- * @param stack_size The stack space that is requested.
- *
- * @retval actual Size allocated after any adjustment.
- * @retval zero The allocation failed.
- */
-size_t _Thread_Stack_Allocate(
-  Thread_Control *the_thread,
-  size_t          stack_size
-);
-
 /**
  * @brief Deallocates thread stack.
  *

cpukit/score/src/threadinitialize.c

@@ -43,8 +43,6 @@ bool _Thread_Initialize(
 )
 {
   uintptr_t                tls_size = _TLS_Get_size();
-  size_t                   actual_stack_size = 0;
-  void                    *stack = NULL;
   #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
     void                  *fp_area = NULL;
   #endif
@@ -92,30 +90,31 @@ bool _Thread_Initialize(
    *  Allocate and Initialize the stack for this thread.
    */
   #if !defined(RTEMS_SCORE_THREAD_ENABLE_USER_PROVIDED_STACK_VIA_API)
-    actual_stack_size = _Thread_Stack_Allocate( the_thread, stack_size );
-    if ( !actual_stack_size || actual_stack_size < stack_size )
-      return false;                     /* stack allocation failed */
+    stack_size = _Stack_Ensure_minimum( stack_size );
+    stack_area = _Stack_Allocate( stack_size );
 
-    stack = the_thread->Start.stack;
+    if ( stack_area == NULL ) {
+      return false;
+    }
   #else
-    if ( !stack_area ) {
-      actual_stack_size = _Thread_Stack_Allocate( the_thread, stack_size );
-      if ( !actual_stack_size || actual_stack_size < stack_size )
-        return false;                     /* stack allocation failed */
+    if ( stack_area == NULL ) {
+      stack_size = _Stack_Ensure_minimum( stack_size );
+      stack_area = _Stack_Allocate( stack_size );
+
+      if ( stack_area == NULL ) {
+        return false;
+      }
 
-      stack = the_thread->Start.stack;
       the_thread->Start.core_allocated_stack = true;
     } else {
-      stack = stack_area;
-      actual_stack_size = stack_size;
       the_thread->Start.core_allocated_stack = false;
     }
   #endif
 
   _Stack_Initialize(
      &the_thread->Start.Initial_stack,
-     stack,
-     actual_stack_size
+     stack_area,
+     stack_size
   );
 
   scheduler_index = 0;

cpukit/score/src/threadstackallocate.c

@@ -1,11 +1,11 @@
 /**
  * @file
- * 
+ *
+ * @ingroup RTEMSScoreStack
+ *
  * @brief Stack Allocate Helper
- * @ingroup RTEMSScoreThread
  */
 
-
 /*
  *  COPYRIGHT (c) 1989-2010.
  *  On-Line Applications Research Corporation (OAR).
@@ -19,28 +19,10 @@
 #include "config.h"
 #endif
 
-#include <rtems/score/threadimpl.h>
 #include <rtems/score/stackimpl.h>
 #include <rtems/config.h>
 
-size_t _Thread_Stack_Allocate(
-  Thread_Control *the_thread,
-  size_t          stack_size
-)
+void *_Stack_Allocate( size_t stack_size )
 {
-  void *stack_addr = 0;
-  size_t the_stack_size;
-  rtems_stack_allocate_hook stack_allocate_hook =
-    rtems_configuration_get_stack_allocate_hook();
-
-  the_stack_size = _Stack_Ensure_minimum( stack_size );
-
-  stack_addr = (*stack_allocate_hook)( the_stack_size );
-
-  if ( !stack_addr )
-    the_stack_size = 0;
-
-  the_thread->Start.stack = stack_addr;
-
-  return the_stack_size;
+  return ( *rtems_configuration_get_stack_allocate_hook() )( stack_size );
 }