Commit afa31d8e authored Aug 12, 2013 by Will Deacon Committed by Russell King Aug 13, 2013

ARM: 7811/1: locks: use early clobber in arch_spin_trylock



The res variable is written before we've finished with the input
operands (namely the lock address), so ensure that we mark it as `early
clobber' to avoid unintended register sharing.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent e35ac62d

arch/arm/include/asm/spinlock.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -107,7 +107,7 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
		" subs %1, %0, %0, ror #16\n"
		" addeq %0, %0, %4\n"
		" strexeq %2, %0, [%3]"
		: "=&r" (slock), "=&r" (contended), "=r" (res)
		: "=&r" (slock), "=&r" (contended), "=&r" (res)
		: "r" (&lock->slock), "I" (1 << TICKET_SHIFT)
		: "cc");
		} while (res);