apic_probe
.apic_probe = madt_probe,
int (*apic_probe)(void);
DEVMETHOD(device_probe, apic_probe),
retval = enumerator->apic_probe();
.apic_probe = mptable_probe,
static void apic_probe( u_int32_t* paddr, int* where );
apic_probe( &paddr, &where );