sh: Provide diagnostic kernel stack checks

Enable kernel stack checking code in both the dynamic ftrace and mcount
code paths. Check the stack to see if it's overflowing and make sure
that the stack pointer contains an address that's either in init_stack
or after the bss.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
index 39224b57c6ef..52a132c24aab 100644
--- a/arch/sh/Kconfig.debug
+++ b/arch/sh/Kconfig.debug
@@ -123,4 +123,15 @@ config SH64_SR_WATCH
         bool "Debug: set SR.WATCH to enable hardware watchpoints and trace"
         depends on SUPERH64
 
+config STACK_DEBUG
+        bool "Enable diagnostic checks of the kernel stack"
+        depends on FUNCTION_TRACER
+        select DEBUG_STACKOVERFLOW
+        default n
+        help
+          This option allows checks to be performed on the kernel stack
+          at runtime. Saying Y here will add overhead to every function
+          call and will therefore incur a major performance hit. Most
+          users should say N.
+
 endmenu