score: Simplify thread wait state handling

Remove the THREAD_WAIT_STATE_READY_AGAIN and simply use the initial value to
indicate that a thread does not wait on something.  Rename
THREAD_WAIT_FLAGS_INITIAL to THREAD_WAIT_STATE_READY.  This change is necessary
so that _Thread_Continue() can be called for threads which never waited on
something (for example dormant threads).

Update #4546.

cpukit/include/rtems/rtems/ratemonimpl.h

@@ -48,9 +48,6 @@ extern "C" {
 #define RATE_MONOTONIC_BLOCKED \
   ( THREAD_WAIT_CLASS_PERIOD | THREAD_WAIT_STATE_BLOCKED )
 
-#define RATE_MONOTONIC_READY_AGAIN \
-  ( THREAD_WAIT_CLASS_PERIOD | THREAD_WAIT_STATE_READY_AGAIN )
-
 /**
  *  @brief Allocates a period control block from
  *  the inactive chain of free period control blocks.

cpukit/include/rtems/score/thread.h

@@ -404,7 +404,7 @@ typedef union {
  * The mutually exclusive wait state flags are
  * - @ref THREAD_WAIT_STATE_INTEND_TO_BLOCK,
  * - @ref THREAD_WAIT_STATE_BLOCKED, and
- * - @ref THREAD_WAIT_STATE_READY_AGAIN.
+ * - @ref THREAD_WAIT_STATE_READY.
  */
 typedef unsigned int Thread_Wait_flags;
 

cpukit/include/rtems/score/threadimpl.h

@@ -2216,16 +2216,20 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_cancel(
   }
 }
 
-/**
- * @brief The initial thread wait flags value set by _Thread_Initialize().
- */
-#define THREAD_WAIT_FLAGS_INITIAL 0x0U
-
 /**
  * @brief Mask to get the thread wait state flags.
  */
 #define THREAD_WAIT_STATE_MASK 0xffU
 
+/**
+ * @brief Indicates that the thread does not wait on something.
+ *
+ * In this wait state, the wait class is zero.  This wait state is set
+ * initially by _Thread_Initialize() and after each wait operation once the
+ * thread is ready again.
+ */
+#define THREAD_WAIT_STATE_READY 0x0U
+
 /**
  * @brief Indicates that the thread begins with the blocking operation.
  *
@@ -2240,13 +2244,6 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_cancel(
  */
 #define THREAD_WAIT_STATE_BLOCKED 0x2U
 
-/**
- * @brief Indicates that a condition to end the thread wait occurred.
- *
- * This could be a timeout, a signal, an event or a resource availability.
- */
-#define THREAD_WAIT_STATE_READY_AGAIN 0x4U
-
 /**
  * @brief Mask to get the thread wait class flags.
  */

cpukit/rtems/src/eventsurrender.c

@@ -42,12 +42,10 @@ static bool _Event_Is_blocking_on_event(
 )
 {
   Thread_Wait_flags wait_flags;
-  Thread_Wait_flags wait_mask;
 
   wait_flags = _Thread_Wait_flags_get( the_thread );
-  wait_mask = THREAD_WAIT_CLASS_MASK | THREAD_WAIT_STATE_READY_AGAIN;
 
-  return ( wait_flags & wait_mask ) == wait_class;
+  return ( wait_flags & THREAD_WAIT_CLASS_MASK ) == wait_class;
 }
 
 static bool _Event_Is_satisfied(
@@ -88,16 +86,14 @@ rtems_status_code _Event_Surrender(
     _Event_Is_blocking_on_event( the_thread, wait_class )
       && _Event_Is_satisfied( the_thread, pending_events, &seized_events )
   ) {
-    Thread_Wait_flags ready_again;
     bool success;
 
     _Event_Satisfy( the_thread, event, pending_events, seized_events );
 
-    ready_again = wait_class | THREAD_WAIT_STATE_READY_AGAIN;
     success = _Thread_Wait_flags_try_change_release(
       the_thread,
       wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK,
-      ready_again
+      THREAD_WAIT_STATE_READY
     );
 
     if ( success ) {
@@ -107,7 +103,7 @@ rtems_status_code _Event_Surrender(
         _Thread_Wait_flags_get( the_thread )
           == ( wait_class | THREAD_WAIT_STATE_BLOCKED )
       );
-      _Thread_Wait_flags_set( the_thread, ready_again );
+      _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
   } else {

cpukit/rtems/src/ratemonperiod.c

@@ -247,7 +247,7 @@ static rtems_status_code _Rate_monotonic_Block_while_active(
   );
   if ( !success ) {
     _Assert(
-      _Thread_Wait_flags_get( executing ) == RATE_MONOTONIC_READY_AGAIN
+      _Thread_Wait_flags_get( executing ) == THREAD_WAIT_STATE_READY
     );
     _Thread_Unblock( executing );
   }

cpukit/rtems/src/ratemontimeout.c

@@ -74,13 +74,13 @@ void _Rate_monotonic_Timeout( Watchdog_Control *the_watchdog )
     success = _Thread_Wait_flags_try_change_release(
       owner,
       RATE_MONOTONIC_INTEND_TO_BLOCK,
-      RATE_MONOTONIC_READY_AGAIN
+      THREAD_WAIT_STATE_READY
     );
     if ( success ) {
       unblock = false;
     } else {
       _Assert( _Thread_Wait_flags_get( owner ) == RATE_MONOTONIC_BLOCKED );
-      _Thread_Wait_flags_set( owner, RATE_MONOTONIC_READY_AGAIN );
+      _Thread_Wait_flags_set( owner, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
 

cpukit/score/src/threadinitialize.c

@@ -299,7 +299,7 @@ static bool _Thread_Try_initialize(
   the_thread->Wait.operations         = &_Thread_queue_Operations_default;
   the_thread->Start.initial_priority  = config->priority;
 
-  RTEMS_STATIC_ASSERT( THREAD_WAIT_FLAGS_INITIAL == 0, Wait_flags );
+  RTEMS_STATIC_ASSERT( THREAD_WAIT_STATE_READY == 0, Wait_flags );
 
   /* POSIX Keys */
   _RBTree_Initialize_empty( &the_thread->Keys.Key_value_pairs );

cpukit/score/src/threadqenqueue.c

@@ -41,9 +41,6 @@
 #define THREAD_QUEUE_BLOCKED \
   (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_BLOCKED)
 
-#define THREAD_QUEUE_READY_AGAIN \
-  (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_READY_AGAIN)
-
 #if defined(RTEMS_SMP)
 /*
  * A global registry of active thread queue links is used to provide deadlock
@@ -560,7 +557,7 @@ static void _Thread_queue_Force_ready_again( Thread_Control *the_thread )
    * We must set the wait flags under protection of the current thread lock,
    * otherwise a _Thread_Timeout() running on another processor may interfere.
    */
-  _Thread_Wait_flags_set( the_thread, THREAD_QUEUE_READY_AGAIN );
+  _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
   _Thread_Wait_restore_default( the_thread );
 }
 
@@ -576,13 +573,13 @@ static bool _Thread_queue_Make_ready_again( Thread_Control *the_thread )
   success = _Thread_Wait_flags_try_change_release(
     the_thread,
     THREAD_QUEUE_INTEND_TO_BLOCK,
-    THREAD_QUEUE_READY_AGAIN
+    THREAD_WAIT_STATE_READY
   );
   if ( success ) {
     unblock = false;
   } else {
     _Assert( _Thread_Wait_flags_get( the_thread ) == THREAD_QUEUE_BLOCKED );
-    _Thread_Wait_flags_set( the_thread, THREAD_QUEUE_READY_AGAIN );
+    _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
     unblock = true;
   }
 

cpukit/score/src/threadtimeout.c

@@ -35,9 +35,8 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
 
   wait_flags = _Thread_Wait_flags_get( the_thread );
 
-  if ( ( wait_flags & THREAD_WAIT_STATE_READY_AGAIN ) == 0 ) {
+  if ( wait_flags != THREAD_WAIT_STATE_READY ) {
     Thread_Wait_flags wait_class;
-    Thread_Wait_flags ready_again;
     bool              success;
 
     _Thread_Wait_cancel( the_thread, &queue_context );
@@ -45,11 +44,10 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
     the_thread->Wait.return_code = status;
 
     wait_class = wait_flags & THREAD_WAIT_CLASS_MASK;
-    ready_again = wait_class | THREAD_WAIT_STATE_READY_AGAIN;
     success = _Thread_Wait_flags_try_change_release(
       the_thread,
       wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK,
-      ready_again
+      THREAD_WAIT_STATE_READY
     );
 
     if ( success ) {
@@ -59,7 +57,7 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
         _Thread_Wait_flags_get( the_thread )
           == ( wait_class | THREAD_WAIT_STATE_BLOCKED )
       );
-      _Thread_Wait_flags_set( the_thread, ready_again );
+      _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
   } else {

testsuites/sptests/spintrcritical08/init.c

@@ -78,7 +78,7 @@ static T_interrupt_test_state interrupt( void *arg )
     T_quiet_eq_int( previous_period_state, RATE_MONOTONIC_ACTIVE );
     T_quiet_eq_int( getState( ctx ), RATE_MONOTONIC_ACTIVE );
     state = T_INTERRUPT_TEST_DONE;
-  } else if ( flags == THREAD_WAIT_FLAGS_INITIAL ) {
+  } else if ( flags == THREAD_WAIT_STATE_READY ) {
     T_quiet_true(
       previous_period_state == RATE_MONOTONIC_ACTIVE
         || previous_period_state == RATE_MONOTONIC_EXPIRED
@@ -100,8 +100,6 @@ static void prepare( void *arg )
 {
   test_context      *ctx;
   rtems_status_code  sc;
-  ISR_Level          level;
-  bool               success;
 
   ctx = arg;
 
@@ -119,15 +117,6 @@ static void prepare( void *arg )
      */
     sc = rtems_rate_monotonic_period( ctx->period, 1 );
   } while ( sc != RTEMS_SUCCESSFUL );
-
-  _ISR_Local_disable( level );
-  success = _Thread_Wait_flags_try_change_release(
-    ctx->thread,
-    RATE_MONOTONIC_READY_AGAIN,
-    THREAD_WAIT_FLAGS_INITIAL
-  );
-  _ISR_Local_enable( level );
-  T_quiet_true( success );
 }
 
 static void action( void *arg )

testsuites/sptests/spintrcritical09/init.c

@@ -32,7 +32,7 @@ static bool is_interrupt_timeout( test_context *ctx )
 {
   Thread_Wait_flags flags = _Thread_Wait_flags_get( ctx->thread );
 
-  return flags == ( THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_READY_AGAIN );
+  return flags == THREAD_WAIT_STATE_READY;
 }
 
 static T_interrupt_test_state interrupt( void *arg )

testsuites/sptests/spintrcritical10/init.c

@@ -92,8 +92,7 @@ static T_interrupt_test_state any_satisfy_before_timeout_interrupt(void *arg)
 
     if (state == T_INTERRUPT_TEST_DONE) {
       rtems_test_assert(
-        _Thread_Wait_flags_get(thread)
+        _Thread_Wait_flags_get(thread) == THREAD_WAIT_STATE_READY
-          == (THREAD_WAIT_CLASS_EVENT | THREAD_WAIT_STATE_READY_AGAIN)
       );
     }
 
@@ -184,8 +183,7 @@ static T_interrupt_test_state all_satisfy_before_timeout_interrupt(void *arg)
 
     if (state == T_INTERRUPT_TEST_DONE) {
       rtems_test_assert(
-        _Thread_Wait_flags_get(thread)
+        _Thread_Wait_flags_get(thread) == THREAD_WAIT_STATE_READY
-          == (THREAD_WAIT_CLASS_EVENT | THREAD_WAIT_STATE_READY_AGAIN)
       );
     }
 
@@ -261,8 +259,7 @@ static T_interrupt_test_state timeout_before_satisfied_interrupt(void *arg)
 
     if (state == T_INTERRUPT_TEST_DONE) {
       rtems_test_assert(
-        _Thread_Wait_flags_get(thread)
+        _Thread_Wait_flags_get(thread) == THREAD_WAIT_STATE_READY
-          == (THREAD_WAIT_CLASS_EVENT | THREAD_WAIT_STATE_READY_AGAIN)
       );
     }
 

testsuites/sptests/spintrcritical22/init.c

@@ -56,7 +56,7 @@ static T_interrupt_test_state release_semaphore(void *arg)
 
     rtems_test_assert(
       _Thread_Wait_flags_get(ctx->main_task_control)
-        == (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_READY_AGAIN)
+        == THREAD_WAIT_STATE_READY
     );
     sem = &ctx->semaphore_control->Core_control.Semaphore;
     rtems_test_assert(sem->count == 0);