[PATCH 6/8] score: Add self-contained semaphore implementation

Sebastian Huber sebastian.huber at embedded-brains.de
Thu Jul 23 12:54:46 UTC 2015


---
 cpukit/libmisc/monitor/mon-prmisc.c            |   1 +
 cpukit/score/Makefile.am                       |   1 +
 cpukit/score/include/rtems/score/statesimpl.h  |   3 +
 cpukit/score/src/semaphore.c                   | 118 +++++++++++++++++++++++++
 testsuites/sptests/spsyslock01/init.c          |  26 ++++++
 testsuites/sptests/spsyslock01/spsyslock01.doc |   5 ++
 6 files changed, 154 insertions(+)
 create mode 100644 cpukit/score/src/semaphore.c

diff --git a/cpukit/libmisc/monitor/mon-prmisc.c b/cpukit/libmisc/monitor/mon-prmisc.c
index ae7f75d..4656ed2 100644
--- a/cpukit/libmisc/monitor/mon-prmisc.c
+++ b/cpukit/libmisc/monitor/mon-prmisc.c
@@ -135,6 +135,7 @@ static const rtems_assoc_t rtems_monitor_state_assoc[] = {
     { "Wsem",   STATES_WAITING_FOR_SEMAPHORE, 0 },
     { "Wsig",   STATES_WAITING_FOR_SIGNAL, 0 },
     { "Wslmtx", STATES_WAITING_FOR_SYS_LOCK_MUTEX, 0 },
+    { "Wslsem", STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE, 0 },
     { "Wsysev", STATES_WAITING_FOR_SYSTEM_EVENT, 0 },
     { "Wterm",  STATES_WAITING_FOR_TERMINATION, 0 },
     { "Wtime",  STATES_WAITING_FOR_TIME, 0 },
diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index 3c117bb..3223470 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -348,6 +348,7 @@ libscore_a_SOURCES += src/profilingisrentryexit.c
 libscore_a_SOURCES += src/mutex.c
 libscore_a_SOURCES += src/once.c
 libscore_a_SOURCES += src/resourceiterate.c
+libscore_a_SOURCES += src/semaphore.c
 libscore_a_SOURCES += src/smpbarrierwait.c
 libscore_a_SOURCES += src/kern_tc.c
 
diff --git a/cpukit/score/include/rtems/score/statesimpl.h b/cpukit/score/include/rtems/score/statesimpl.h
index 4ad8786..7805ca4 100644
--- a/cpukit/score/include/rtems/score/statesimpl.h
+++ b/cpukit/score/include/rtems/score/statesimpl.h
@@ -88,6 +88,8 @@ extern "C" {
 #define STATES_WAITING_FOR_JOIN                0x1000000
 /** This macro corresponds to a task waiting for a <sys/lock.h> mutex. */
 #define STATES_WAITING_FOR_SYS_LOCK_MUTEX      0x2000000
+/** This macro corresponds to a task waiting for a <sys/lock.h> semaphore. */
+#define STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE  0x4000000
 
 /** This macro corresponds to a task which is in an interruptible
  *  blocking state.
@@ -106,6 +108,7 @@ extern "C" {
                                  STATES_WAITING_FOR_BARRIER            | \
                                  STATES_WAITING_FOR_BSD_WAKEUP         | \
                                  STATES_WAITING_FOR_SYS_LOCK_MUTEX     | \
+                                 STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE | \
                                  STATES_WAITING_FOR_RWLOCK             )
 
 /** This macro corresponds to a task waiting which is blocked. */
diff --git a/cpukit/score/src/semaphore.c b/cpukit/score/src/semaphore.c
new file mode 100644
index 0000000..acf50b8
--- /dev/null
+++ b/cpukit/score/src/semaphore.c
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2015 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems at 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 <sys/lock.h>
+
+#include <rtems/score/assert.h>
+#include <rtems/score/threadimpl.h>
+#include <rtems/score/threadqimpl.h>
+
+#if HAVE_STRUCT__THREAD_QUEUE_QUEUE
+
+#define SEMAPHORE_TQ_OPERATIONS &_Thread_queue_Operations_priority
+
+static Thread_queue_Queue *_Semaphore_Get_thread_queue(
+  struct _Semaphore_Control *sem
+)
+{
+  return (Thread_queue_Queue *) &sem->_Queue;
+}
+
+static Thread_Control *_Semaphore_Queue_acquire(
+  struct _Semaphore_Control *sem,
+  ISR_lock_Context *lock_context
+)
+{
+  Thread_Control *executing;
+
+  _ISR_lock_ISR_disable( lock_context );
+  executing = _Thread_Executing;
+  _Thread_queue_Queue_acquire_critical(
+    _Semaphore_Get_thread_queue( sem ),
+    &executing->Potpourri_stats,
+    lock_context
+  );
+
+  return executing;
+}
+
+static void _Semaphore_Queue_release(
+  struct _Semaphore_Control *sem,
+  ISR_lock_Context *lock_context
+)
+{
+  _Thread_queue_Queue_release(
+    _Semaphore_Get_thread_queue( sem ),
+    lock_context
+  );
+}
+
+void _Semaphore_Wait( struct _Semaphore_Control *sem )
+{
+  ISR_lock_Context lock_context;
+  Thread_Control *executing;
+  unsigned int count;
+
+  executing = _Semaphore_Queue_acquire( sem, &lock_context );
+
+  count = sem->_count;
+  if ( count > 0 ) {
+    sem->_count = count - 1;
+    _Semaphore_Queue_release( sem, &lock_context );
+  } else {
+    _Thread_queue_Enqueue_critical(
+      _Semaphore_Get_thread_queue( sem ),
+      SEMAPHORE_TQ_OPERATIONS,
+      executing,
+      STATES_WAITING_FOR_SYS_LOCK_SEMAPHORE,
+      0,
+      0,
+      &lock_context
+    );
+  }
+}
+
+void _Semaphore_Post( struct _Semaphore_Control *sem )
+{
+  ISR_lock_Context lock_context;
+  Thread_queue_Heads *heads;
+
+  _Semaphore_Queue_acquire( sem, &lock_context );
+
+  heads = _Semaphore_Get_thread_queue( sem )->heads;
+  if ( heads == NULL ) {
+    _Assert( sem->_count < UINT_MAX );
+    ++sem->_count;
+    _Semaphore_Queue_release( sem, &lock_context );
+  } else {
+    const Thread_queue_Operations *operations;
+    Thread_Control *first;
+
+    operations = SEMAPHORE_TQ_OPERATIONS;
+    first = ( *operations->first )( heads );
+
+    _Thread_queue_Extract_critical(
+      _Semaphore_Get_thread_queue( sem ),
+      operations,
+      first,
+      &lock_context
+    );
+  }
+}
+
+#endif /* HAVE_STRUCT__THREAD_QUEUE_QUEUE */
diff --git a/testsuites/sptests/spsyslock01/init.c b/testsuites/sptests/spsyslock01/init.c
index 7d93676..f6a2d3f 100644
--- a/testsuites/sptests/spsyslock01/init.c
+++ b/testsuites/sptests/spsyslock01/init.c
@@ -37,12 +37,15 @@ const char rtems_test_name[] = "SPSYSLOCK 1";
 
 #define EVENT_REC_MTX_PRIO_INV RTEMS_EVENT_6
 
+#define EVENT_SEM_WAIT RTEMS_EVENT_7
+
 typedef struct {
   rtems_id high;
   rtems_id mid;
   rtems_id low;
   struct _Mutex_Control mtx;
   struct _Mutex_recursive_Control rec_mtx;
+  struct _Semaphore_Control sem;
   bool flag;
 } test_context;
 
@@ -60,15 +63,19 @@ static void test_initialization(test_context *ctx)
 {
   struct _Mutex_Control mtx = _MUTEX_INITIALIZER;
   struct _Mutex_recursive_Control rec_mtx = _MUTEX_RECURSIVE_INITIALIZER;
+  struct _Semaphore_Control sem = _SEMAPHORE_INITIALIZER(1);
 
   _Mutex_Initialize(&ctx->mtx);
   _Mutex_recursive_Initialize(&ctx->rec_mtx);
+  _Semaphore_Initialize(&ctx->sem, 1);
 
   rtems_test_assert(memcmp(&mtx, &ctx->mtx, sizeof(mtx)) == 0);
   rtems_test_assert(memcmp(&rec_mtx, &ctx->rec_mtx, sizeof(rec_mtx)) == 0);
+  rtems_test_assert(memcmp(&sem, &ctx->sem, sizeof(sem)) == 0);
 
   _Mutex_Destroy(&mtx);
   _Mutex_recursive_Destroy(&rec_mtx);
+  _Semaphore_Destroy(&sem);
 }
 
 static void test_recursive_acquire_normal(test_context *ctx)
@@ -153,6 +160,19 @@ static void test_prio_inv_recursive(test_context *ctx)
   rtems_test_assert(ctx->flag);
 }
 
+static void test_sem(test_context *ctx)
+{
+  struct _Semaphore_Control *sem = &ctx->sem;
+
+  _Semaphore_Wait(sem);
+  ctx->flag = false;
+  send_events(ctx, EVENT_SEM_WAIT);
+  rtems_test_assert(!ctx->flag);
+  _Semaphore_Post(sem);
+  rtems_test_assert(ctx->flag);
+  _Semaphore_Post(sem);
+}
+
 static void mid_task(rtems_task_argument arg)
 {
   rtems_test_assert(0);
@@ -226,6 +246,11 @@ static void high_task(rtems_task_argument arg)
       sc = rtems_task_suspend(ctx->mid);
       rtems_test_assert(sc == RTEMS_SUCCESSFUL);
     }
+
+    if ((events & EVENT_SEM_WAIT) != 0) {
+      _Semaphore_Wait(&ctx->sem);
+      ctx->flag = true;
+    }
   }
 }
 
@@ -265,6 +290,7 @@ static void test(void)
   test_recursive_acquire_recursive(ctx);
   test_prio_inv_normal(ctx);
   test_prio_inv_recursive(ctx);
+  test_sem(ctx);
 
   send_events(ctx, EVENT_MTX_DEADLOCK);
 
diff --git a/testsuites/sptests/spsyslock01/spsyslock01.doc b/testsuites/sptests/spsyslock01/spsyslock01.doc
index 440759d..1a7384c 100644
--- a/testsuites/sptests/spsyslock01/spsyslock01.doc
+++ b/testsuites/sptests/spsyslock01/spsyslock01.doc
@@ -14,7 +14,12 @@ directives:
   - _Mutex_recursive_Try_acquire()
   - _Mutex_recursive_Release()
   - _Mutex_recursive_Destroy()
+  - _Semaphore_Initialize()
+  - _Semaphore_Wait()
+  - _Semaphore_Post()
+  - _Semaphore_Destroy()
 
 concepts:
 
   - Ensure that self-contained mutexes and recursive mutexes work.
+  - Ensure that self-contained semaphores work.
-- 
1.8.4.5



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