Re: [PATCH 1/2] taskmode.c: Ensure all error checking is done before modifying executing

[Sebastian Huber]

On 05/12/17 17:13, Joel Sherrill wrote:
Also use single conditional expressions to simplify error checking.
Combined, this all resulted in a block of SMP enabled error checking.
Updates #3000.
---
  cpukit/rtems/src/taskmode.c | 33 +++++++++++++++++++++++++++++++--
  1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/cpukit/rtems/src/taskmode.c b/cpukit/rtems/src/taskmode.c
index a345409..49648ac 100644
--- a/cpukit/rtems/src/taskmode.c
+++ b/cpukit/rtems/src/taskmode.c
@@ -43,6 +43,33 @@ rtems_status_code rtems_task_mode(
    if ( !previous_mode_set )
      return RTEMS_INVALID_ADDRESS;
  
+#if defined( RTEMS_SMP )
+  /*
+   * When in SMP, you cannot disable preemption for a thread or
+   * alter its interrupt level. It must be fully preemptible with
+   * all interrupts enabled.
+   */
+  if ( rtems_configuration_is_smp_enabled() ) {
+    if ( mask & RTEMS_PREEMPT_MASK ) {
+      if ( !_Modes_Is_preempt( mode_set ) ) {
+        return RTEMS_NOT_IMPLEMENTED;
+      }
+    }
+
+    if ( mask & RTEMS_INTERRUPT_MASK ) {
+      if (_Modes_Get_interrupt_level( mode_set ) != 0 ) {

if ( _Modes...

+        return RTEMS_NOT_IMPLEMENTED;
+      }

There should be a test case for the new else path 
_Modes_Get_interrupt_level( mode_set ) == 0.

+    }
+  }
+#endif
+
+  /*
+   * Complete all error checking before doing any operations which
+   * impact the executing thread. There should be no errors returned
+   * past this point.
+   */
+
    executing     = _Thread_Get_executing();
    api = executing->API_Extensions[ THREAD_API_RTEMS ];
    asr = &api->Signal;
@@ -63,18 +90,18 @@ rtems_status_code rtems_task_mode(
     *  These are generic thread scheduling characteristics.
     */
    preempt_enabled = false;
+#if !defined( RTEMS_SMP )
    if ( mask & RTEMS_PREEMPT_MASK ) {
-#if defined( RTEMS_SMP )
      if ( rtems_configuration_is_smp_enabled() &&
           !_Modes_Is_preempt( mode_set ) ) {
        return RTEMS_NOT_IMPLEMENTED;
      }
-#endif
      bool is_preempt_enabled = _Modes_Is_preempt( mode_set );
  
      preempt_enabled = !executing->is_preemptible && is_preempt_enabled;
      executing->is_preemptible = is_preempt_enabled;
    }
+#endif
  
    if ( mask & RTEMS_TIMESLICE_MASK ) {
      if ( _Modes_Is_timeslice(mode_set) ) {
@@ -88,8 +115,10 @@ rtems_status_code rtems_task_mode(
    /*
     *  Set the new interrupt level
     */
+#if !defined( RTEMS_SMP )
    if ( mask & RTEMS_INTERRUPT_MASK )
      _Modes_Set_interrupt_level( mode_set );
+#endif
  
    /*
     *  This is specific to the RTEMS API

--
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.hu...@embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.

_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel