1 files changed, 78 insertions, 0 deletions
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c
new file mode 100644
index 000000000000..4f1b068e9b7a
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c
@@ -0,0 +1,78 @@
+#include <config.h>
+
+#include "preempt.h"
+
+#include "assume.h"
+#include "locks.h"
+
+/* Support NR_CPUS of at most 64 */
+#define CPU_PREEMPTION_LOCKS_INIT0 LOCK_IMPL_INITIALIZER
+#define CPU_PREEMPTION_LOCKS_INIT1 \
+	CPU_PREEMPTION_LOCKS_INIT0, CPU_PREEMPTION_LOCKS_INIT0
+#define CPU_PREEMPTION_LOCKS_INIT2 \
+	CPU_PREEMPTION_LOCKS_INIT1, CPU_PREEMPTION_LOCKS_INIT1
+#define CPU_PREEMPTION_LOCKS_INIT3 \
+	CPU_PREEMPTION_LOCKS_INIT2, CPU_PREEMPTION_LOCKS_INIT2
+#define CPU_PREEMPTION_LOCKS_INIT4 \
+	CPU_PREEMPTION_LOCKS_INIT3, CPU_PREEMPTION_LOCKS_INIT3
+#define CPU_PREEMPTION_LOCKS_INIT5 \
+	CPU_PREEMPTION_LOCKS_INIT4, CPU_PREEMPTION_LOCKS_INIT4
+
+/*
+ * Simulate disabling preemption by locking a particular cpu. NR_CPUS
+ * should be the actual number of cpus, not just the maximum.
+ */
+struct lock_impl cpu_preemption_locks[NR_CPUS] = {
+	CPU_PREEMPTION_LOCKS_INIT0
+#if (NR_CPUS - 1) & 1
+	, CPU_PREEMPTION_LOCKS_INIT0
+#endif
+#if (NR_CPUS - 1) & 2
+	, CPU_PREEMPTION_LOCKS_INIT1
+#endif
+#if (NR_CPUS - 1) & 4
+	, CPU_PREEMPTION_LOCKS_INIT2
+#endif
+#if (NR_CPUS - 1) & 8
+	, CPU_PREEMPTION_LOCKS_INIT3
+#endif
+#if (NR_CPUS - 1) & 16
+	, CPU_PREEMPTION_LOCKS_INIT4
+#endif
+#if (NR_CPUS - 1) & 32
+	, CPU_PREEMPTION_LOCKS_INIT5
+#endif
+};
+
+#undef CPU_PREEMPTION_LOCKS_INIT0
+#undef CPU_PREEMPTION_LOCKS_INIT1
+#undef CPU_PREEMPTION_LOCKS_INIT2
+#undef CPU_PREEMPTION_LOCKS_INIT3
+#undef CPU_PREEMPTION_LOCKS_INIT4
+#undef CPU_PREEMPTION_LOCKS_INIT5
+
+__thread int thread_cpu_id;
+__thread int preempt_disable_count;
+
+void preempt_disable(void)
+{
+	BUG_ON(preempt_disable_count < 0 || preempt_disable_count == INT_MAX);
+
+	if (preempt_disable_count++)
+		return;
+
+	thread_cpu_id = nondet_int();
+	assume(thread_cpu_id >= 0);
+	assume(thread_cpu_id < NR_CPUS);
+	lock_impl_lock(&cpu_preemption_locks[thread_cpu_id]);
+}
+
+void preempt_enable(void)
+{
+	BUG_ON(preempt_disable_count < 1);
+
+	if (--preempt_disable_count)
+		return;
+
+	lock_impl_unlock(&cpu_preemption_locks[thread_cpu_id]);
+}