Added checks for index in ThreadLocalStorage APIs

Added checks for ( xIndex >= 0 ) in ThreadLocalStorage APIs

Author: AniruddhaKanhere

tasks.c

@@ -3592,7 +3592,8 @@ static portTASK_FUNCTION( prvIdleTask, pvParameters )
  {
  TCB_t * pxTCB;
 
- if( xIndex < configNUM_THREAD_LOCAL_STORAGE_POINTERS )
+ if( ( xIndex >= 0 ) &&
+ ( xIndex < configNUM_THREAD_LOCAL_STORAGE_POINTERS ) )
  {
  pxTCB = prvGetTCBFromHandle( xTaskToSet );
  configASSERT( pxTCB != NULL );
@@ -3611,7 +3612,8 @@ static portTASK_FUNCTION( prvIdleTask, pvParameters )
  void * pvReturn = NULL;
  TCB_t * pxTCB;
 
- if( xIndex < configNUM_THREAD_LOCAL_STORAGE_POINTERS )
+ if( ( xIndex >= 0 ) &&
+ ( xIndex < configNUM_THREAD_LOCAL_STORAGE_POINTERS ) )
  {
  pxTCB = prvGetTCBFromHandle( xTaskToQuery );
  pvReturn = pxTCB->pvThreadLocalStoragePointers[ xIndex ];