HelenOS sources

CPU_OWNER          50 kernel/generic/src/synch/irq_spinlock.c 	return atomic_load_explicit(&lock->owner, memory_order_relaxed) == CPU_OWNER;
CPU_OWNER          60 kernel/generic/src/synch/irq_spinlock.c 	cpu_t *cpu = CPU_OWNER;
HelenOS homepage, sources at GitHub