From 2ba2a48d02164a7f51fbd1686173080240579002 Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Mon, 23 Feb 2009 01:31:11 -0500
Subject: [PATCH] Run 2 writers and show single flip error case

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---
 formal-model/urcu/Makefile  |  8 ++++++++
 formal-model/urcu/urcu.spin | 16 ++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/formal-model/urcu/Makefile b/formal-model/urcu/Makefile
index 0dc8b2c..7802c7f 100644
--- a/formal-model/urcu/Makefile
+++ b/formal-model/urcu/Makefile
@@ -26,6 +26,7 @@ default:
 	make urcu_free_no_rmb | tee urcu_free_no_rmb.log
 	make urcu_free_no_wmb | tee urcu_free_no_wmb.log
 	make urcu_free_no_mb | tee urcu_free_no_mb.log
+	make urcu_free_single_flip | tee urcu_free_single_flip.log
 	make asserts | tee asserts.log
 	make summary
 
@@ -72,6 +73,13 @@ urcu_free_no_mb: clean urcu_free_ltl urcu_free_no_mb_define run
 urcu_free_no_mb_define:
 	cp urcu_free_no_mb.define .input.define
 
+urcu_free_single_flip: clean urcu_free_ltl urcu_free_single_flip_define run
+	cp .input.spin $@.spin.input
+	-cp .input.spin.trail $@.spin.input.trail
+
+urcu_free_single_flip_define:
+	cp urcu_free_single_flip.define .input.define
+
 urcu_free_ltl:
 	touch .input.define
 	cat DEFINES > pan.ltl
diff --git a/formal-model/urcu/urcu.spin b/formal-model/urcu/urcu.spin
index cc84e51..7f94d3b 100644
--- a/formal-model/urcu/urcu.spin
+++ b/formal-model/urcu/urcu.spin
@@ -21,9 +21,9 @@
 /* Promela validation variables. */
 
 #define NR_READERS 1
-#define NR_WRITERS 1
+#define NR_WRITERS 2
 
-#define NR_PROCS 2
+#define NR_PROCS 3
 
 #define get_pid()	(_pid)
 
@@ -123,6 +123,8 @@ bit free_done = 0;
 byte read_generation = 1;
 bit data_access = 0;
 
+bit write_lock = 0;
+
 inline ooo_mem(i)
 {
 	atomic {
@@ -222,6 +224,13 @@ active [NR_WRITERS] proctype urcu_writer()
 	}
 	ooo_mem(i);
 
+	do
+	:: write_lock == 0 ->
+		write_lock = 1;
+		break;
+	:: else ->
+		skip;
+	od;
 	smp_mb(i);
 	ooo_mem(i);
 	tmp = READ_CACHED_VAR(urcu_gp_ctr);
@@ -231,6 +240,7 @@ active [NR_WRITERS] proctype urcu_writer()
 	//smp_mc(i);
 	wait_for_quiescent_state(tmp, i, j);
 	//smp_mc(i);
+#ifndef SINGLE_FLIP
 	ooo_mem(i);
 	tmp = READ_CACHED_VAR(urcu_gp_ctr);
 	ooo_mem(i);
@@ -238,6 +248,7 @@ active [NR_WRITERS] proctype urcu_writer()
 	//smp_mc(i);
 	ooo_mem(i);
 	wait_for_quiescent_state(tmp, i, j);
+#endif
 	ooo_mem(i);
 	smp_mb(i);
 	/* free-up step, e.g., kfree(). */
@@ -245,5 +256,6 @@ active [NR_WRITERS] proctype urcu_writer()
 	atomic {
 		last_free_gen = old_gen;
 		free_done = 1;
+		write_lock = 0;
 	}
 }
-- 
2.34.1