[rtems commit] score: PR2179: Fix initially locked PCP mutexes

[Sebastian Huber]

Module:    rtems
Branch:    4.10
Commit:    272a80b776b862d5432338b39e1e4bcaf74ad4b2
Changeset: http://git.rtems.org/rtems/commit/?id=272a80b776b862d5432338b39e1e4bcaf74ad4b2

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Thu May 22 09:31:13 2014 +0200

score: PR2179: Fix initially locked PCP mutexes

Elevate the priority of the creating task to the ceiling priority in
case a semaphore is created as initially locked.

---

 cpukit/score/src/coremutex.c     |    5 +++--
 testsuites/sptests/sp65/init.c   |   35 +++++++++++++++++++++++++++++++++++
 testsuites/sptests/sp65/sp65.doc |    2 ++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/cpukit/score/src/coremutex.c b/cpukit/score/src/coremutex.c
index dcd2e77..9745f82 100644
--- a/cpukit/score/src/coremutex.c
+++ b/cpukit/score/src/coremutex.c
@@ -64,9 +64,9 @@ CORE_mutex_Status _CORE_mutex_Initialize(
     the_mutex->holder_id  = _Thread_Executing->Object.id;
     if ( _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) ||
          _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ) {
+      Priority_Control ceiling = the_mutex->Attributes.priority_ceiling;
 
-      if ( _Thread_Executing->current_priority <
-             the_mutex->Attributes.priority_ceiling )
+      if ( _Thread_Executing->current_priority < ceiling )
        return CORE_MUTEX_STATUS_CEILING_VIOLATED;
 #ifdef __RTEMS_STRICT_ORDER_MUTEX__
        _Chain_Prepend_unprotected( &_Thread_Executing->lock_mutex,
@@ -75,6 +75,7 @@ CORE_mutex_Status _CORE_mutex_Initialize(
 #endif
 
       _Thread_Executing->resource_count++;
+      _Thread_Change_priority( _Thread_Executing, ceiling, false );
     }
   } else {
     the_mutex->nest_count = 0;
diff --git a/testsuites/sptests/sp65/init.c b/testsuites/sptests/sp65/init.c
index 288d4e0..8d82102 100644
--- a/testsuites/sptests/sp65/init.c
+++ b/testsuites/sptests/sp65/init.c
@@ -24,6 +24,17 @@ rtems_task Task_1(
   rtems_task_argument arg
 );
 
+static void assert_priority(rtems_task_priority expected)
+{
+  rtems_status_code sc;
+  rtems_task_priority prio;
+
+  sc = rtems_task_set_priority(RTEMS_SELF, RTEMS_CURRENT_PRIORITY, &prio);
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  rtems_test_assert(prio == expected);
+}
+
 rtems_task Init(
   rtems_task_argument ignored
 )
@@ -34,6 +45,30 @@ rtems_task Init(
   puts( "\n\n*** TEST " TEST_NAME " ***" );
 
   /*
+   * Verify that an initially locked priority ceiling mutex elevates the
+   * priority of the creating task.
+   */
+
+  status = rtems_semaphore_create(
+    rtems_build_name( 's','e','m','1' ),
+    0,
+    RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_PRIORITY_CEILING,
+    1,
+    &Mutex_id
+  );
+  rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+  assert_priority(1);
+
+  status = rtems_semaphore_release(Mutex_id);
+  rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+  assert_priority(TASK_PRIORITY);
+
+  status = rtems_semaphore_delete(Mutex_id);
+  rtems_test_assert(status == RTEMS_SUCCESSFUL);
+
+  /*
    *  Create binary semaphore (a.k.a. Mutex) with Priority Ceiling
    *  attribute.
    */
diff --git a/testsuites/sptests/sp65/sp65.doc b/testsuites/sptests/sp65/sp65.doc
index 39a1ee1..603adcb 100644
--- a/testsuites/sptests/sp65/sp65.doc
+++ b/testsuites/sptests/sp65/sp65.doc
@@ -26,3 +26,5 @@ concepts:
 + Verify the priority ceiling mutex getting released which results in a thread
   being unblocked and the unblocked thread's priority being elevated.
 
++ Verify that an initially locked priority ceiling mutex elevates the priority
+  of the creating task.