From 5870ac55678115857215a4199f519263599ee341 Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Wed, 5 Jan 2000 22:19:21 +0000
Subject: Added support for simple binary semaphores in addition to the high
 power binary/mutex style semaphores already supported by RTEMS.  This was
 done at the request of Eric Norum <eric@cls.usask.ca> in support of his
 effort to port EPICS to RTEMS.  This change consisted of changing the
 nesting_allowed boolean into a lock_nesting_behavior enumerated value as well
 as allowing the core mutex object to optionally support ensuring that the
 holder of a binary semaphore released it. Finally, a more subtle enhancement
 was to allow the non-holder to release a priority inheritance/ceiling mutex
 and still allow the holding task to return to its original priority.

---
 cpukit/score/src/coremutex.c          | 13 +++++++++++-
 cpukit/score/src/coremutexseize.c     | 22 ++++++++++++--------
 cpukit/score/src/coremutexsurrender.c | 39 +++++++++++++++--------------------
 3 files changed, 42 insertions(+), 32 deletions(-)

(limited to 'cpukit/score/src')

diff --git a/cpukit/score/src/coremutex.c b/cpukit/score/src/coremutex.c
index 2f5b4a6675..a5842efb91 100644
--- a/cpukit/score/src/coremutex.c
+++ b/cpukit/score/src/coremutex.c
@@ -55,7 +55,18 @@ void _CORE_mutex_Initialize(
  */
 
   the_mutex->Attributes = *the_mutex_attributes;
-  the_mutex->lock          = initial_lock;
+  the_mutex->lock       = initial_lock;
+
+#if 0
+  if ( !the_mutex_attributes->only_owner_release &&
+       the_mutex_attributes->nesting_allowed ) {
+    _Internal_error_Occurred(
+      INTERNAL_ERROR_CORE,
+      TRUE,
+      INTERNAL_ERROR_BAD_ATTRIBUTES
+    );
+  }
+#endif
 
   if ( initial_lock == CORE_MUTEX_LOCKED ) {
     the_mutex->nest_count = 1;
diff --git a/cpukit/score/src/coremutexseize.c b/cpukit/score/src/coremutexseize.c
index c2a70da762..db576c6ef1 100644
--- a/cpukit/score/src/coremutexseize.c
+++ b/cpukit/score/src/coremutexseize.c
@@ -94,15 +94,19 @@ void _CORE_mutex_Seize(
     return;
   }
 
-  if ( _Objects_Are_ids_equal(
-              _Thread_Executing->Object.id, the_mutex->holder_id ) ) {
-    if ( _CORE_mutex_Is_nesting_allowed( &the_mutex->Attributes ) )
-      the_mutex->nest_count++;
-    else 
-      executing->Wait.return_code = CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED;
-
-    _ISR_Enable( level );
-    return;
+  if ( _Thread_Is_executing( the_mutex->holder ) ) {
+    switch ( the_mutex->Attributes.lock_nesting_behavior ) {
+      case CORE_MUTEX_NESTING_ACQUIRES:
+        the_mutex->nest_count++;
+        _ISR_Enable( level );
+        return;
+      case CORE_MUTEX_NESTING_IS_ERROR:
+        executing->Wait.return_code = CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED;
+        _ISR_Enable( level );
+        return;
+      case CORE_MUTEX_NESTING_BLOCKS:
+        break;
+    }
   }
 
   if ( !wait ) {
diff --git a/cpukit/score/src/coremutexsurrender.c b/cpukit/score/src/coremutexsurrender.c
index 447a5421e8..d64badae1f 100644
--- a/cpukit/score/src/coremutexsurrender.c
+++ b/cpukit/score/src/coremutexsurrender.c
@@ -49,9 +49,9 @@ CORE_mutex_Status _CORE_mutex_Surrender(
 )
 {
   Thread_Control *the_thread;
-  Thread_Control *executing;
+  Thread_Control *holder;
 
-  executing = _Thread_Executing;
+  holder    = the_mutex->holder;
 
   /*
    *  The following code allows a thread (or ISR) other than the thread
@@ -61,20 +61,9 @@ CORE_mutex_Status _CORE_mutex_Surrender(
    *  must be released by the thread which acquired them.
    */ 
 
-  if ( the_mutex->Attributes.allow_nesting ) {
-    if ( !_Objects_Are_ids_equal(
-             _Thread_Executing->Object.id, the_mutex->holder_id ) ) {
-  
-      switch ( the_mutex->Attributes.discipline ) {
-        case CORE_MUTEX_DISCIPLINES_FIFO:
-        case CORE_MUTEX_DISCIPLINES_PRIORITY:
-          break;
-        case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
-        case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
-          return( CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE );
-          break;
-      }
-    }
+  if ( the_mutex->Attributes.only_owner_release ) {
+    if ( !_Thread_Is_executing( holder ) )
+      return( CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE );
   }
 
   /* XXX already unlocked -- not right status */
@@ -85,9 +74,15 @@ CORE_mutex_Status _CORE_mutex_Surrender(
   the_mutex->nest_count--;
 
   if ( the_mutex->nest_count != 0 ) {
-    if ( the_mutex->Attributes.allow_nesting )
-      return( CORE_MUTEX_STATUS_SUCCESSFUL );
-    return( CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED );
+    switch ( the_mutex->Attributes.lock_nesting_behavior ) {
+      case CORE_MUTEX_NESTING_ACQUIRES:
+        return CORE_MUTEX_STATUS_SUCCESSFUL;
+      case CORE_MUTEX_NESTING_IS_ERROR:
+        /* should never occur */
+        return CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED;
+      case CORE_MUTEX_NESTING_BLOCKS:
+        break;
+    }
   }
 
   _Thread_Executing->resource_count--;
@@ -106,9 +101,9 @@ CORE_mutex_Status _CORE_mutex_Surrender(
       break;
     case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING:
     case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT:
-      if ( executing->resource_count == 0 && 
-           executing->real_priority != executing->current_priority ) {
-         _Thread_Change_priority( executing, executing->real_priority, TRUE );
+      if ( holder->resource_count == 0 && 
+           holder->real_priority != holder->current_priority ) {
+         _Thread_Change_priority( holder, holder->real_priority, TRUE );
       }
       break;
   }
-- 
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