target/arm: ensure we use current exception state after SCR update

target/arm: ensure we use current exception state after SCR update

A write to the SCR can change the effective EL by droppping the system
from secure to non-secure mode. However if we use a cached current_el
from before the change we'll rebuild the flags incorrectly. To fix
this we introduce the ARM_CP_NEWEL CP flag to indicate the new EL
should be used when recomputing the flags.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191212114734.6962-1-alex.bennee@linaro.org
Cc: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20191209143723.6368-1-alex.bennee@linaro.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>