Commit c2bdac14 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: spinlock: Document the EX based spin_unlock 



Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent ab1e8660

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)