This implements basic -fstack-protector support, based on the early ARM
version in c743f380. The SMP case is
limited to the initial canary value, while the UP case handles per-task
granularity (limited to 32-bit sh until a new enough sh64 compiler
manifests itself).
Signed-off-by: NFilippo Arcidiacono <filippo.arcidiacono@st.com>
Reviewed-by: NCarmelo Amoroso <carmelo.amoroso@st.com>
Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This is the very basic stuff without the changing canary upon
task switch yet.  Just the Kconfig option and a constant canary
value initialized at boot time.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>