Commit 0286237c authored Dec 30, 2014 by Rohit Vaswani

ARM64: spinlock: Move the dsb+sev after the stlxr has succeeded



In arch_read_unlock, the earlier commit
88a06607 had added the DSB+SEV
before checking if the stlxr has successfully completed.
Move the DSB + SEV after the compare instruction to prevent
unnecessary SEVs.

Change-Id: I58bdad4db333a2acc31bcdc0e911c493cd3417bd
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>

parent 6a8a77bd

arch/arm64/include/asm/spinlock.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -206,11 +206,11 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)
		"1: ldxr %w0, %2\n"
		" sub %w0, %w0, #1\n"
		" stlxr %w1, %w0, %2\n"
		" cbnz %w1, 1b\n"
		#ifdef CONFIG_ARM64_SEV_IN_LOCK_UNLOCK
		" dsb sy\n"
		" sev\n"
		#endif
		" cbnz %w1, 1b\n"
		: "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock)
		:
		: "memory");