Return stack is a programmable option on some ETM and PTM hardware.
Adds the option flags to enable this from the perf event command line.
Signed-off-by: NMike Leach <mike.leach@linaro.org>
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>