If CONFIG_ATOMIC64, we can use a host cmpxchg and provide
atomicity across processes; otherwise we have no choice but
to continue using start/end_exclusive.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220323005839.94327-4-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
330ea9d1d8