ARC: spinlock: Document the EX based spin_unlock (c2bdac14) · Commits · e / devices / android_kernel_oneplus_sm8150

arch/arc/include/asm/spinlock.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -296,6 +296,12 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
		*/
		smp_mb();

		/*
		* EX is not really required here, a simple STore of 0 suffices.
		* However this causes tasklist livelocks in SystemC based SMP virtual
		* platforms where the systemc core scheduler uses EX as a cue for
		* moving to next core. Do a git log of this file for details
		*/
		__asm__ __volatile__(
		" ex %0, [%1] \n"
		: "+r" (val)