rtems: Add scheduler processor add/remove

Update #2797.

1 files changed, 144 insertions, 0 deletions

diff --git a/cpukit/rtems/src/schedulerremoveprocessor.c b/cpukit/rtems/src/schedulerremoveprocessor.c
new file mode 100644
index 0000000000..21b7c4611e
--- /dev/null
+++ b/cpukit/rtems/src/schedulerremoveprocessor.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2016 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/rtems/tasks.h>
+#include <rtems/score/schedulerimpl.h>
+#include <rtems/config.h>
+
+#if defined(RTEMS_SMP)
+typedef struct {
+  const Scheduler_Control *scheduler;
+  rtems_status_code        status;
+} Scheduler_Processor_removal_context;
+
+static bool _Scheduler_Check_processor_removal(
+  Thread_Control *the_thread,
+  void           *arg
+)
+{
+  Scheduler_Processor_removal_context *iter_context;
+  Thread_queue_Context                 queue_context;
+  ISR_lock_Context                     state_context;
+
+  if ( the_thread->is_idle ) {
+    return false;
+  }
+
+  iter_context = arg;
+
+  _Thread_Wait_acquire( the_thread, &queue_context );
+  _Thread_State_acquire_critical( the_thread, &state_context );
+
+  if ( _Thread_Scheduler_get_home( the_thread ) == iter_context->scheduler ) {
+    iter_context->status = RTEMS_RESOURCE_IN_USE;
+  }
+
+  _Thread_State_release_critical( the_thread, &state_context );
+  _Thread_Wait_release( the_thread, &queue_context );
+  return iter_context->status != RTEMS_SUCCESSFUL;
+}
+#endif
+
+rtems_status_code rtems_scheduler_remove_processor(
+  rtems_id scheduler_id,
+  uint32_t cpu_index
+)
+{
+  const Scheduler_Control             *scheduler;
+#if defined(RTEMS_SMP)
+  uint32_t                             processor_count;
+  Scheduler_Processor_removal_context  iter_context;
+  ISR_lock_Context                     lock_context;
+  Scheduler_Context                   *scheduler_context;
+  Per_CPU_Control                     *cpu;
+  Per_CPU_Control                     *cpu_self;
+#endif
+
+  scheduler = _Scheduler_Get_by_id( scheduler_id );
+  if ( scheduler == NULL ) {
+    return RTEMS_INVALID_ID;
+  }
+
+  if ( cpu_index >= rtems_configuration_get_maximum_processors() ) {
+    return RTEMS_INVALID_NUMBER;
+  }
+
+#if defined(RTEMS_SMP)
+  iter_context.scheduler = scheduler;
+  iter_context.status = RTEMS_SUCCESSFUL;
+  scheduler_context = _Scheduler_Get_context( scheduler );
+  cpu = _Per_CPU_Get_by_index( cpu_index );
+
+  _Objects_Allocator_lock();
+
+  if ( cpu->Scheduler.control != scheduler ) {
+    _Objects_Allocator_unlock();
+    return RTEMS_INVALID_NUMBER;
+  }
+
+  /*
+   * This prevents the selection of this scheduler instance by new threads in
+   * case the processor count changes to zero.
+   */
+  _ISR_lock_ISR_disable( &lock_context );
+  _Scheduler_Acquire_critical( scheduler, &lock_context );
+  processor_count = scheduler_context->processor_count - 1;
+  scheduler_context->processor_count = processor_count;
+  _Scheduler_Release_critical( scheduler, &lock_context );
+  _ISR_lock_ISR_enable( &lock_context );
+
+  if ( processor_count == 0 ) {
+    _Thread_Iterate( _Scheduler_Check_processor_removal, &iter_context );
+  }
+
+  _ISR_lock_ISR_disable( &lock_context );
+  _Scheduler_Acquire_critical( scheduler, &lock_context );
+
+  if ( iter_context.status == RTEMS_SUCCESSFUL ) {
+    Thread_Control *idle;
+    Scheduler_Node *scheduler_node;
+
+    cpu->Scheduler.control = NULL;
+    cpu->Scheduler.context = NULL;
+    idle = ( *scheduler->Operations.remove_processor )( scheduler, cpu );
+    cpu->Scheduler.idle_if_online_and_unused = idle;
+
+    scheduler_node = _Thread_Scheduler_get_home_node( idle );
+    _Priority_Plain_extract(
+      &scheduler_node->Wait.Priority,
+      &idle->Real_priority
+    );
+    _Assert( _Priority_Is_empty( &scheduler_node->Wait.Priority ) );
+    _Chain_Extract_unprotected( &scheduler_node->Thread.Wait_node );
+    _Assert( _Chain_Is_empty( &idle->Scheduler.Wait_nodes ) );
+    _Chain_Extract_unprotected( &scheduler_node->Thread.Scheduler_node.Chain );
+    _Assert( _Chain_Is_empty( &idle->Scheduler.Scheduler_nodes ) );
+  } else {
+    ++scheduler_context->processor_count;
+  }
+
+  cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
+  _Scheduler_Release_critical( scheduler, &lock_context );
+  _ISR_lock_ISR_enable( &lock_context );
+  _Thread_Dispatch_enable( cpu_self );
+  _Objects_Allocator_unlock();
+  return iter_context.status;
+#else
+  return RTEMS_RESOURCE_IN_USE;
+#endif
+}