43f67b215337afe62e39475ef author Chris Metcalf 1304363593 -0400 committer Chris Metcalf 1304534407 -0400 arch/tile: allow nonatomic stores to interoperate with fast atomic syscalls This semantic was already true for atomic operations within the kernel, and this change makes it true for the fast atomic syscalls (__NR_cmpxchg and __NR_atomic_update) as well. Previously, user-space had to use the fast atomic syscalls exclusively to update memory, since raw stores could lose a race with the atomic update code even when the atomic update hadn't actually modified the value. With this change, we no longer write back the value to memory if it hasn't changed. This allows certain types of idioms in user space to work as expected, e.g. "atomic exchange" to acquire a spinlock, followed by a raw store of zero to release the lock. Signed-off-by: Chris Metcalf ~ Yê—