score: Thread life cycle re-implementation

The thread deletion is now supported on SMP.

This change fixes the following PRs:

PR1814: SMP race condition between stack free and dispatch

PR2035: psxcancel reveals NULL pointer access in _Thread_queue_Extract()

The POSIX cleanup handler are now called in the right context (should be
called in the context of the terminating thread).

http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_09.html

Add a user extension the reflects a thread termination event.  This is
used to reclaim the Newlib reentrancy structure (may use file
operations), the POSIX cleanup handlers and the POSIX key destructors.

1 files changed, 7 insertions, 20 deletions

diff --git a/cpukit/score/src/heapfree.c b/cpukit/score/src/heapfree.c
index c45c294f3f..4e69146232 100644
--- a/cpukit/score/src/heapfree.c
+++ b/cpukit/score/src/heapfree.c
@@ -83,26 +83,13 @@
     bool do_free = true;
     Heap_Block *const next = block->Protection_begin.next_delayed_free_block;
 
-    /*
-     * Sometimes after a free the allocated area is still in use.  An example
-     * is the task stack of a thread that deletes itself.  The thread dispatch
-     * disable level is a way to detect this use case.
-     */
-    if ( _Thread_Dispatch_is_enabled() ) {
-      if ( next == NULL ) {
-        _Heap_Protection_delay_block_free( heap, block );
-        do_free = false;
-      } else if ( next == HEAP_PROTECTION_OBOLUS ) {
-        _Heap_Protection_check_free_block( heap, block );
-      } else {
-        _Heap_Protection_block_error( heap, block );
-      }
-    } else if ( next == NULL ) {
-      /*
-       * This is a hack to prevent heavy workspace fragmentation which would
-       * lead to test suite failures.
-       */
-      _Heap_Protection_free_all_delayed_blocks( heap );
+    if ( next == NULL ) {
+      _Heap_Protection_delay_block_free( heap, block );
+      do_free = false;
+    } else if ( next == HEAP_PROTECTION_OBOLUS ) {
+      _Heap_Protection_check_free_block( heap, block );
+    } else {
+      _Heap_Protection_block_error( heap, block );
     }
 
     return do_free;