Initialize stack area in _NewContext()

Instead of initializing the stack (when INIT_STACKS is enabled) in start_task()
and _fiber_start(), do it in _NewContext().  This helps to both reduce code
duplication AND ensure that all contexts get an initialized stack (previously
the background/idle task's was missed).

Change-Id: If2d50309d2be48fac937f5d0ae96b9de185c0fe2
Signed-off-by: Peter Mitsis <peter.mitsis@windriver.com>

arch/arc/core/context.c

@@ -124,6 +124,10 @@ void _NewContext(
 
 	tCCS *pCcs = (tCCS *) pStackMem;
 
+#ifdef CONFIG_INIT_STACKS
+    k_memset(pStackMem, 0xaa, stackSize);
+#endif
+
 	/* carve the context entry struct from the "base" of the stack */
 
 	pInitCtx = (struct init_stack_frame *)(STACK_ROUND_DOWN(stackEnd) -

arch/arm/core/nanocontext.c

@@ -117,6 +117,10 @@ void _NewContext(
 	struct __esf *pInitCtx;
 	tCCS *pCcs = (tCCS *) pStackMem;
 
+#ifdef CONFIG_INIT_STACKS
+    k_memset(pStackMem, 0xaa, stackSize);
+#endif
+
 	/* carve the context entry struct from the "base" of the stack */
 
 	pInitCtx = (struct __esf *)(STACK_ROUND_DOWN(stackEnd) -

arch/x86/core/nanocontext.c

@@ -301,6 +301,10 @@ void _NewContext(
 {
 	unsigned long *pInitialContext;
 
+#ifdef CONFIG_INIT_STACKS
+    k_memset(pStackMem, 0xaa, stackSize);
+#endif
+
 	/* carve the context entry struct from the "base" of the stack */
 
 	pInitialContext =

kernel/microkernel/k_task.c

@@ -208,10 +208,6 @@ void start_task(struct k_proc *X,	 /* ptr to task control block */
 
 /* Note: the field X->worksize now represents the task size in bytes */
 
-#ifdef CONFIG_INIT_STACKS
-	memset(X->workspace, 0xaa, X->worksize);
-#endif
-
 	contextOptions = 0;
 	_START_TASK_ARCH(X, &contextOptions);
 

kernel/nanokernel/nano_fiber.c

@@ -79,10 +79,6 @@ void _fiber_start(char *pStack,
 	tCCS *ccs;
 	unsigned int imask;
 
-#ifdef CONFIG_INIT_STACKS
-	memset((char *)pStack, 0xaa, stackSize);
-#endif
-
 	ccs = (tCCS *) pStack;
 	_NewContext(pStack,
 			  stackSize,