consolidate per-arch stack overflow debugging options

Original posting:

	http://lkml.kernel.org/r/20121214184202.F54094D9@kernel.stglabs.ibm.com

Several architectures have similar stack debugging config options.
They all pretty much do the same thing, some with slightly
differing help text.

This patch changes the architectures to instead enable a Kconfig
boolean, and then use that boolean in the generic Kconfig.debug
to present the actual menu option.  This removes a bunch of
duplication and adds consistency across arches.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com> [for tile]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/Kconfig.debug

@@ -1475,6 +1475,27 @@ config ASYNC_RAID6_TEST
 
 	  If unsure, say N.
 
+config HAVE_DEBUG_STACKOVERFLOW
+	bool
+
+config DEBUG_STACKOVERFLOW
+	bool "Check for stack overflows"
+	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
+	---help---
+	  Say Y here if you want to check for overflows of kernel, IRQ
+	  and exception stacks (if your archicture uses them). This
+	  option will show detailed messages if free stack space drops
+	  below a certain limit.
+
+	  These kinds of bugs usually occur when call-chains in the
+	  kernel get too deep, especially when interrupts are
+	  involved.
+
+	  Use this in cases where you see apparently random memory
+	  corruption, especially if it appears in 'struct thread_info'
+
+	  If in doubt, say "N".
+
 source "samples/Kconfig"
 
 source "lib/Kconfig.kgdb"