Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/tools/memory-model/litmus-tests/MP+polocks.litmus b/tools/memory-model/litmus-tests/MP+polocks.litmus
new file mode 100644
index 0000000000..e6af05f700
--- /dev/null
+++ b/tools/memory-model/litmus-tests/MP+polocks.litmus
@@ -0,0 +1,35 @@
+C MP+polocks
+
+(*
+ * Result: Never
+ *
+ * This litmus test demonstrates how lock acquisitions and releases can
+ * stand in for smp_load_acquire() and smp_store_release(), respectively.
+ * In other words, when holding a given lock (or indeed after releasing a
+ * given lock), a CPU is not only guaranteed to see the accesses that other
+ * CPUs made while previously holding that lock, it is also guaranteed
+ * to see all prior accesses by those other CPUs.
+ *)
+
+{}
+
+P0(int *buf, int *flag, spinlock_t *mylock) // Producer
+{
+	WRITE_ONCE(*buf, 1);
+	spin_lock(mylock);
+	WRITE_ONCE(*flag, 1);
+	spin_unlock(mylock);
+}
+
+P1(int *buf, int *flag, spinlock_t *mylock) // Consumer
+{
+	int r0;
+	int r1;
+
+	spin_lock(mylock);
+	r0 = READ_ONCE(*flag);
+	spin_unlock(mylock);
+	r1 = READ_ONCE(*buf);
+}
+
+exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *)