Add futex wakeup spin model

[urcu.git] / formal-model / futex-wakeup / futex.spin

diff --git a/formal-model/futex-wakeup/futex.spin b/formal-model/futex-wakeup/futex.spin
new file mode 100644 (file)
index 0000000..9f6ddd4
--- /dev/null
+++ b/formal-model/futex-wakeup/futex.spin
@@ -0,0 +1,120 @@
+/*
+ * futex.spin: Promela code to validate futex wakeup algorithm.
+ *
+ * Algorithm verified :
+ *
+ * queue = 0;
+ * fut = 0;
+ * runvar = 0;
+ *
+ *                            Waker
+ *                            queue = 1;
+ *                            if (fut == -1) {
+ *                              fut = 0;
+ *                            }
+ *
+ * Waiter
+ * while (1) {
+ *   progress:
+ *   fut = fut - 1;
+ *   if (queue == 1) {
+ *     fut = 0;
+ *   } else {
+ *     if (fut == -1) {
+ *        while (fut == -1) { }
+ *     }
+ *   }
+ *   queue = 0;
+ * }
+ *
+ * if queue = 1, then !_np
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers
+ */
+
+int queue = 0;
+int fut = 0;
+
+active proctype waker()
+{
+       queue = 1;
+
+       if
+       :: (fut == -1) ->
+               fut = 0;
+       :: else ->
+               skip;
+       fi;
+
+       queue = 1;
+
+       if
+       :: (fut == -1) ->
+               fut = 0;
+       :: else ->
+               skip;
+       fi;
+
+#ifdef INJ_QUEUE_NO_WAKE
+       queue = 1;
+#endif
+}
+
+
+active proctype waiter()
+{
+       do
+       :: 1 ->
+#ifndef INJ_LATE_DEC
+               fut = fut - 1;
+#endif
+               if
+               :: (queue == 1) ->
+#ifndef INJ_LATE_DEC
+                       fut = 0;
+#endif
+                       skip;
+               :: else ->
+#ifdef INJ_LATE_DEC
+                       fut = fut - 1;
+#endif
+                       if
+                       :: (fut == -1) ->
+                               do
+                               :: 1 ->
+                                       if
+                                       :: (fut == -1) ->
+                                               if
+                                               :: (queue == 0) ->
+progress_A:
+                                                       skip;
+                                               :: else
+                                                       skip;
+                                               fi;
+                                               skip;
+                                       :: else ->
+                                               break;
+                                       fi;
+                               od;
+                       :: else ->
+                               skip;
+                       fi;
+               fi;
+progress_B:
+               queue = 0;
+       od;
+}