score: Remove PRIORITY_PSEUDO_ISR thread priority

The uniprocessor schedulers had some special case logic for the
PRIORITY_PSEUDO_ISR priority.  Tasks with a priority of PRIORITY_PSEUDO_ISR
were allowed to preempt a not preemptible task.  If other higher priority task
are made ready while a PRIORITY_PSEUDO_ISR task preempts a not preemptible
task, then the other tasks run before the not preemptible task.  This made the
RTEMS_NO_PREEMPT mode ineffective.

Remove the PRIORITY_PSEUDO_ISR special case logic.  This simplifies the
uniprocessor schedulers.  Move the uniprocessor-specific scheduler support to
the new header file <rtems/score/scheduleruniimpl.h>.

Close #2365.

16 files changed, 43 insertions, 69 deletions

diff --git a/cpukit/score/src/mpci.c b/cpukit/score/src/mpci.c
index 3b525a2066..458031c794 100644
--- a/cpukit/score/src/mpci.c
+++ b/cpukit/score/src/mpci.c
@@ -162,7 +162,7 @@ static void _MPCI_Create_server( void )
   memset( &config, 0, sizeof( config ) );
   config.scheduler = &_Scheduler_Table[ 0 ];
   config.name = _Objects_Build_name( 'M', 'P', 'C', 'I' );
-  config.priority = PRIORITY_PSEUDO_ISR;
+  config.priority = PRIORITY_MINIMUM;
   config.is_fp = CPU_ALL_TASKS_ARE_FP;
   config.stack_size = _Stack_Minimum()
     + _MPCI_Configuration.extra_mpci_receive_server_stack
diff --git a/cpukit/score/src/scheduleredfblock.c b/cpukit/score/src/scheduleredfblock.c
index 56f7c9c021..cb7ab91450 100644
--- a/cpukit/score/src/scheduleredfblock.c
+++ b/cpukit/score/src/scheduleredfblock.c
@@ -47,11 +47,11 @@ void _Scheduler_EDF_Block(
   Scheduler_Node          *node
 )
 {
-  _Scheduler_Generic_block(
+  _Scheduler_uniprocessor_Block(
     scheduler,
     the_thread,
     node,
     _Scheduler_EDF_Extract_body,
-    _Scheduler_EDF_Schedule_body
+    _Scheduler_EDF_Get_highest_ready
   );
 }
diff --git a/cpukit/score/src/scheduleredfchangepriority.c b/cpukit/score/src/scheduleredfchangepriority.c
index 26ce1c348f..de17ca0fad 100644
--- a/cpukit/score/src/scheduleredfchangepriority.c
+++ b/cpukit/score/src/scheduleredfchangepriority.c
@@ -71,5 +71,8 @@ void _Scheduler_EDF_Update_priority(
 
   _Scheduler_EDF_Extract( context, the_node );
   _Scheduler_EDF_Enqueue( context, the_node, insert_priority );
-  _Scheduler_EDF_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_EDF_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/scheduleredfschedule.c b/cpukit/score/src/scheduleredfschedule.c
index d0acea7a30..40c5ab2c06 100644
--- a/cpukit/score/src/scheduleredfschedule.c
+++ b/cpukit/score/src/scheduleredfschedule.c
@@ -46,5 +46,8 @@ void _Scheduler_EDF_Schedule(
   Thread_Control          *the_thread
 )
 {
-  _Scheduler_EDF_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_EDF_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/scheduleredfunblock.c b/cpukit/score/src/scheduleredfunblock.c
index d6604686e3..4638eedf71 100644
--- a/cpukit/score/src/scheduleredfunblock.c
+++ b/cpukit/score/src/scheduleredfunblock.c
@@ -62,23 +62,5 @@ void _Scheduler_EDF_Unblock(
 
   the_node->priority = priority;
   _Scheduler_EDF_Enqueue( context, the_node, insert_priority );
-
-  /*
-   *  If the thread that was unblocked is more important than the heir,
-   *  then we have a new heir.  This may or may not result in a
-   *  context switch.
-   *
-   *  Normal case:
-   *    If the current thread is preemptible, then we need to do
-   *    a context switch.
-   *  Pseudo-ISR case:
-   *    Even if the thread isn't preemptible, if the new heir is
-   *    a pseudo-ISR system task, we need to do a context switch.
-   */
-  if ( priority < _Thread_Get_priority( _Thread_Heir ) ) {
-    _Scheduler_Update_heir(
-      the_thread,
-      priority == ( SCHEDULER_EDF_PRIO_MSB | PRIORITY_PSEUDO_ISR )
-    );
-  }
+  _Scheduler_uniprocessor_Unblock( scheduler, the_thread, priority );
 }
diff --git a/cpukit/score/src/scheduleredfyield.c b/cpukit/score/src/scheduleredfyield.c
index d83e1d9268..d38bea705a 100644
--- a/cpukit/score/src/scheduleredfyield.c
+++ b/cpukit/score/src/scheduleredfyield.c
@@ -55,5 +55,5 @@ void _Scheduler_EDF_Yield(
 
   _Scheduler_EDF_Extract( context, the_node );
   _Scheduler_EDF_Enqueue( context, the_node, the_node->priority );
-  _Scheduler_EDF_Schedule_body( scheduler, the_thread, true );
+  _Scheduler_uniprocessor_Yield( scheduler, _Scheduler_EDF_Get_highest_ready );
 }
diff --git a/cpukit/score/src/schedulerpriorityblock.c b/cpukit/score/src/schedulerpriorityblock.c
index 53636940dc..ffc7a3ad86 100644
--- a/cpukit/score/src/schedulerpriorityblock.c
+++ b/cpukit/score/src/schedulerpriorityblock.c
@@ -49,11 +49,11 @@ void _Scheduler_priority_Block(
   Scheduler_Node          *node
 )
 {
-  _Scheduler_Generic_block(
+  _Scheduler_uniprocessor_Block(
     scheduler,
     the_thread,
     node,
     _Scheduler_priority_Extract_body,
-    _Scheduler_priority_Schedule_body
+    _Scheduler_priority_Get_highest_ready
   );
 }
diff --git a/cpukit/score/src/schedulerprioritychangepriority.c b/cpukit/score/src/schedulerprioritychangepriority.c
index 8a059763de..3588a2ce42 100644
--- a/cpukit/score/src/schedulerprioritychangepriority.c
+++ b/cpukit/score/src/schedulerprioritychangepriority.c
@@ -96,5 +96,8 @@ void _Scheduler_priority_Update_priority(
     );
   }
 
-  _Scheduler_priority_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_priority_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/schedulerpriorityschedule.c b/cpukit/score/src/schedulerpriorityschedule.c
index bde749f9bc..bb7cf87399 100644
--- a/cpukit/score/src/schedulerpriorityschedule.c
+++ b/cpukit/score/src/schedulerpriorityschedule.c
@@ -46,5 +46,8 @@ void _Scheduler_priority_Schedule(
   Thread_Control          *the_thread
 )
 {
-  _Scheduler_priority_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_priority_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/schedulerpriorityunblock.c b/cpukit/score/src/schedulerpriorityunblock.c
index 190c126908..f9b6cabff7 100644
--- a/cpukit/score/src/schedulerpriorityunblock.c
+++ b/cpukit/score/src/schedulerpriorityunblock.c
@@ -76,19 +76,5 @@ void _Scheduler_priority_Unblock (
 
   /* TODO: flash critical section? */
 
-  /*
-   *  If the thread that was unblocked is more important than the heir,
-   *  then we have a new heir.  This may or may not result in a
-   *  context switch.
-   *
-   *  Normal case:
-   *    If the current thread is preemptible, then we need to do
-   *    a context switch.
-   *  Pseudo-ISR case:
-   *    Even if the thread isn't preemptible, if the new heir is
-   *    a pseudo-ISR system task, we need to do a context switch.
-   */
-  if ( priority < _Thread_Get_priority( _Thread_Heir ) ) {
-    _Scheduler_Update_heir( the_thread, priority == PRIORITY_PSEUDO_ISR );
-  }
+  _Scheduler_uniprocessor_Unblock( scheduler, the_thread, priority );
 }
diff --git a/cpukit/score/src/schedulerpriorityyield.c b/cpukit/score/src/schedulerpriorityyield.c
index 77fcecc418..adb443df94 100644
--- a/cpukit/score/src/schedulerpriorityyield.c
+++ b/cpukit/score/src/schedulerpriorityyield.c
@@ -59,5 +59,8 @@ void _Scheduler_priority_Yield(
     _Chain_Append_unprotected( ready_chain, &the_thread->Object.Node );
   }
 
-  _Scheduler_priority_Schedule_body( scheduler, the_thread, true );
+  _Scheduler_uniprocessor_Yield(
+    scheduler,
+    _Scheduler_priority_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/schedulersimpleblock.c b/cpukit/score/src/schedulersimpleblock.c
index a8229d409f..dfd18df3a2 100644
--- a/cpukit/score/src/schedulersimpleblock.c
+++ b/cpukit/score/src/schedulersimpleblock.c
@@ -47,11 +47,11 @@ void _Scheduler_simple_Block(
   Scheduler_Node          *node
 )
 {
-  _Scheduler_Generic_block(
+  _Scheduler_uniprocessor_Block(
     scheduler,
     the_thread,
     node,
     _Scheduler_simple_Extract,
-    _Scheduler_simple_Schedule_body
+    _Scheduler_simple_Get_highest_ready
   );
 }
diff --git a/cpukit/score/src/schedulersimplechangepriority.c b/cpukit/score/src/schedulersimplechangepriority.c
index b4711dfd01..5c53c96fb3 100644
--- a/cpukit/score/src/schedulersimplechangepriority.c
+++ b/cpukit/score/src/schedulersimplechangepriority.c
@@ -60,5 +60,8 @@ void _Scheduler_simple_Update_priority(
 
   _Scheduler_simple_Extract( scheduler, the_thread, node );
   _Scheduler_simple_Insert( &context->Ready, the_thread, new_priority );
-  _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_simple_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/schedulersimpleschedule.c b/cpukit/score/src/schedulersimpleschedule.c
index 4108fdaee8..83a3fed7fe 100644
--- a/cpukit/score/src/schedulersimpleschedule.c
+++ b/cpukit/score/src/schedulersimpleschedule.c
@@ -46,5 +46,8 @@ void _Scheduler_simple_Schedule(
   Thread_Control          *the_thread
 )
 {
-  _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Schedule(
+    scheduler,
+    _Scheduler_simple_Get_highest_ready
+  );
 }
diff --git a/cpukit/score/src/schedulersimpleunblock.c b/cpukit/score/src/schedulersimpleunblock.c
index 7791503d7a..436f20ac38 100644
--- a/cpukit/score/src/schedulersimpleunblock.c
+++ b/cpukit/score/src/schedulersimpleunblock.c
@@ -58,23 +58,5 @@ void _Scheduler_simple_Unblock(
   priority = _Thread_Get_priority( the_thread );
   insert_priority = SCHEDULER_PRIORITY_APPEND( priority );
   _Scheduler_simple_Insert( &context->Ready, the_thread, insert_priority );
-
-  /*
-   *  If the thread that was unblocked is more important than the heir,
-   *  then we have a new heir.  This may or may not result in a
-   *  context switch.
-   *
-   *  Normal case:
-   *    If the current thread is preemptible, then we need to do
-   *    a context switch.
-   *  Pseudo-ISR case:
-   *    Even if the thread isn't preemptible, if the new heir is
-   *    a pseudo-ISR system task, we need to do a context switch.
-   */
-  if ( priority < _Thread_Get_priority( _Thread_Heir ) ) {
-    _Scheduler_Update_heir(
-      the_thread,
-      priority == PRIORITY_PSEUDO_ISR
-    );
-  }
+  _Scheduler_uniprocessor_Unblock( scheduler, the_thread, priority );
 }
diff --git a/cpukit/score/src/schedulersimpleyield.c b/cpukit/score/src/schedulersimpleyield.c
index c25cceb8a7..ed8dd5b4cc 100644
--- a/cpukit/score/src/schedulersimpleyield.c
+++ b/cpukit/score/src/schedulersimpleyield.c
@@ -58,5 +58,8 @@ void _Scheduler_simple_Yield(
   insert_priority = (unsigned int) _Thread_Get_priority( the_thread );
   insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
   _Scheduler_simple_Insert( &context->Ready, the_thread, insert_priority );
-  _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
+  _Scheduler_uniprocessor_Yield(
+    scheduler,
+    _Scheduler_simple_Get_highest_ready
+  );
 }