+static struct event_constraint *
+dyn_constraint(struct cpu_hw_events *cpuc, struct event_constraint *c, int idx)
+{
+ WARN_ON_ONCE(!cpuc->constraint_list);
+
+ if (!(c->flags & PERF_X86_EVENT_DYNAMIC)) {
+ struct event_constraint *cx;
+
+ /*
+ * grab pre-allocated constraint entry
+ */
+ cx = &cpuc->constraint_list[idx];
+
+ /*
+ * initialize dynamic constraint
+ * with static constraint
+ */
+ *cx = *c;
+
+ /*
+ * mark constraint as dynamic
+ */
+ cx->flags |= PERF_X86_EVENT_DYNAMIC;
+ c = cx;
+ }
+
+ return c;
+}
+