score: Add and use _Per_CPU_Is_ISR_in_progress()

Add _Per_CPU_Is_ISR_in_progress() as an optimized version of
_ISR_Is_in_progress().

cpukit/include/rtems/score/isr.h

@@ -147,18 +147,6 @@ void _ISR_Handler_initialization ( void );
  */
 void _ISR_Handler( void );
 
-/**
- * @brief Checks if an ISR in progress.
- *
- * This function returns true if the processor is currently servicing
- * and interrupt and false otherwise.   A return value of true indicates
- * that the caller is an interrupt service routine, NOT a thread.
- *
- * @retval true Returns true when called from an ISR.
- * @retval false Returns false when not called from an ISR.
- */
-bool _ISR_Is_in_progress( void );
-
 #ifdef __cplusplus
 }
 #endif

cpukit/include/rtems/score/isrlevel.h

@@ -144,6 +144,17 @@ typedef uint32_t   ISR_Level;
     RTEMS_COMPILER_MEMORY_BARRIER();  \
   } while (0)
 
+/**
+ * @brief Checks if an ISR in progress.
+ *
+ * This function returns true, if the processor is currently servicing
+ * and interrupt, and false otherwise.   A return value of true indicates
+ * that the caller is an interrupt service routine, **not** a thread.
+ *
+ * @return true Returns true, if called from within an ISR, otherwise false.
+ */
+bool _ISR_Is_in_progress( void );
+
 /** @} */
 
 #ifdef __cplusplus

cpukit/include/rtems/score/percpu.h

@@ -683,6 +683,16 @@ static inline struct _Thread_Control *_Per_CPU_Get_executing(
   return cpu->executing;
 }
 
+static inline bool _Per_CPU_Is_ISR_in_progress( const Per_CPU_Control *cpu )
+{
+#if CPU_PROVIDES_ISR_IS_IN_PROGRESS == TRUE
+  (void) cpu;
+  return _ISR_Is_in_progress();
+#else
+  return cpu->isr_nest_level != 0;
+#endif
+}
+
 static inline bool _Per_CPU_Is_processor_online(
   const Per_CPU_Control *cpu
 )

cpukit/score/src/threadrestart.c

@@ -538,7 +538,7 @@ Status_Control _Thread_Restart(
 
   if (
     the_thread == _Per_CPU_Get_executing( cpu_self ) &&
-    !_ISR_Is_in_progress()
+    !_Per_CPU_Is_ISR_in_progress( cpu_self )
   ) {
     ignored_life_states = THREAD_LIFE_PROTECTED | THREAD_LIFE_CHANGE_DEFERRED;
   } else {