[PATCH 15/25] score: Error for non-preemptible tasks on SMP

[Sebastian Huber]

A common use case for disabled preemption was to ensure mutual exclusion
on single-processor configurations.  On SMP this does not work.

To abandon non-preemptible tasks simplifies the scheduler.
---
 cpukit/rtems/src/taskcreate.c               |    1 +
 cpukit/rtems/src/taskmode.c                 |   13 ++++++++++++-
 cpukit/sapi/include/confdefs.h              |    6 +++++-
 cpukit/score/src/threadinitialize.c         |    7 +++++++
 testsuites/smptests/smpunsupported01/init.c |   20 +++++++++++++++++++-
 5 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/cpukit/rtems/src/taskcreate.c b/cpukit/rtems/src/taskcreate.c
index 64ad1eb..471990d 100644
--- a/cpukit/rtems/src/taskcreate.c
+++ b/cpukit/rtems/src/taskcreate.c
@@ -19,6 +19,7 @@
 #endif
 
 #include <rtems/system.h>
+#include <rtems/config.h>
 #include <rtems/rtems/status.h>
 #include <rtems/rtems/support.h>
 #include <rtems/rtems/modes.h>
diff --git a/cpukit/rtems/src/taskmode.c b/cpukit/rtems/src/taskmode.c
index d9c7fce..eb3636d 100644
--- a/cpukit/rtems/src/taskmode.c
+++ b/cpukit/rtems/src/taskmode.c
@@ -19,6 +19,7 @@
 #endif
 
 #include <rtems/system.h>
+#include <rtems/config.h>
 #include <rtems/rtems/status.h>
 #include <rtems/rtems/support.h>
 #include <rtems/rtems/modes.h>
@@ -67,8 +68,18 @@ rtems_status_code rtems_task_mode(
   /*
    *  These are generic thread scheduling characteristics.
    */
-  if ( mask & RTEMS_PREEMPT_MASK )
+  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
+
     executing->is_preemptible = _Modes_Is_preempt( mode_set );
+  }
 
   if ( mask & RTEMS_TIMESLICE_MASK ) {
     if ( _Modes_Is_timeslice(mode_set) ) {
diff --git a/cpukit/sapi/include/confdefs.h b/cpukit/sapi/include/confdefs.h
index b7cbfaa..c969fa7 100644
--- a/cpukit/sapi/include/confdefs.h
+++ b/cpukit/sapi/include/confdefs.h
@@ -1021,7 +1021,11 @@ const rtems_libio_helper rtems_fs_init_helper =
 #endif
 
 #ifndef CONFIGURE_INIT_TASK_INITIAL_MODES
-  #define CONFIGURE_INIT_TASK_INITIAL_MODES RTEMS_NO_PREEMPT
+  #if defined(RTEMS_SMP) && defined(CONFIGURE_SMP_APPLICATION)
+    #define CONFIGURE_INIT_TASK_INITIAL_MODES RTEMS_DEFAULT_MODES
+  #else
+    #define CONFIGURE_INIT_TASK_INITIAL_MODES RTEMS_NO_PREEMPT
+  #endif
 #endif
 
 #ifndef CONFIGURE_INIT_TASK_ARGUMENTS
diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 4c40ae8..cc74573 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -18,6 +18,7 @@
 #endif
 
 #include <rtems/system.h>
+#include <rtems/config.h>
 #include <rtems/score/apiext.h>
 #include <rtems/score/context.h>
 #include <rtems/score/interr.h>
@@ -57,6 +58,12 @@ bool _Thread_Initialize(
   bool                 extension_status;
   int                  i;
 
+#if defined( RTEMS_SMP )
+  if ( rtems_configuration_is_smp_enabled() && !is_preemptible ) {
+    return false;
+  }
+#endif
+
   /*
    *  Initialize the Ada self pointer
    */
diff --git a/testsuites/smptests/smpunsupported01/init.c b/testsuites/smptests/smpunsupported01/init.c
index 3379de6..bfce1f2 100644
--- a/testsuites/smptests/smpunsupported01/init.c
+++ b/testsuites/smptests/smpunsupported01/init.c
@@ -21,6 +21,8 @@
 static void test(void)
 {
   rtems_status_code sc;
+  rtems_mode mode;
+  rtems_id id;
 
   rtems_test_assert(rtems_configuration_is_smp_enabled());
 
@@ -35,6 +37,22 @@ static void test(void)
 
   sc = rtems_task_variable_get(RTEMS_SELF, NULL, NULL);
   rtems_test_assert(sc == RTEMS_NOT_IMPLEMENTED);
+
+  sc = rtems_task_variable_get(RTEMS_SELF, NULL, NULL);
+  rtems_test_assert(sc == RTEMS_NOT_IMPLEMENTED);
+
+  sc = rtems_task_mode(RTEMS_NO_PREEMPT, RTEMS_PREEMPT_MASK, &mode);
+  rtems_test_assert(sc == RTEMS_NOT_IMPLEMENTED);
+
+  sc = rtems_task_create(
+    rtems_build_name('T', 'A', 'S', 'K'),
+    RTEMS_MINIMUM_PRIORITY,
+    RTEMS_MINIMUM_STACK_SIZE,
+    RTEMS_NO_PREEMPT,
+    RTEMS_DEFAULT_ATTRIBUTES,
+    &id
+  );
+  rtems_test_assert(sc == RTEMS_UNSATISFIED);
 }
 
 static void Init(rtems_task_argument arg)
@@ -55,7 +73,7 @@ static void Init(rtems_task_argument arg)
 
 #define CONFIGURE_SMP_MAXIMUM_PROCESSORS 1
 
-#define CONFIGURE_MAXIMUM_TASKS 1
+#define CONFIGURE_MAXIMUM_TASKS 2
 
 #define CONFIGURE_RTEMS_INIT_TASKS_TABLE
 
-- 
1.7.7