+#ifdef CONFIG_SMP
+/* The performance counters used by NMI_LOCAL_APIC don't trigger when
+ * the CPU is idle. To make sure the NMI watchdog really ticks on all
+ * CPUs during the test make them busy.
+ */
+static __init void nmi_cpu_busy(void *data)
+{
+ volatile int *endflag = data;
+ local_irq_enable();
+ /* Intentionally don't use cpu_relax here. This is
+ to make sure that the performance counter really ticks,
+ even if there is a simulator or similar that catches the
+ pause instruction. On a real HT machine this is fine because
+ all other CPUs are busy with "useless" delay loops and don't
+ care if they get somewhat less cycles. */
+ while (*endflag == 0)
+ barrier();
+}
+#endif
+