* - For !LLSC, cmpxchg() needs to use that lock (see above) and there is lot
* of kernel code which calls xchg()/cmpxchg() on same data (see llist.h)
* Hence xchg() needs to follow same locking rules.
- *
- * Technically the lock is also needed for UP (boils down to irq save/restore)
- * but we can cheat a bit since cmpxchg() atomic_ops_lock() would cause irqs to
- * be disabled thus can't possibly be interrupted/preempted/clobbered by xchg()
- * Other way around, xchg is one instruction anyways, so can't be interrupted
- * as such
*/
-#if !defined(CONFIG_ARC_HAS_LLSC) && defined(CONFIG_SMP)
+#ifndef CONFIG_ARC_HAS_LLSC
#define arch_xchg(ptr, with) \
({ \