Kprobes: indicate kretprobe support in Kconfig

Add CONFIG_HAVE_KRETPROBES to the arch/<arch>/Kconfig file for relevant
architectures with kprobes support.  This facilitates easy handling of
in-kernel modules (like samples/kprobes/kretprobe_example.c) that depend on
kretprobes being present in the kernel.

Thanks to Sam Ravnborg for helping make the patch more lean.

Per Mathieu's suggestion, added CONFIG_KRETPROBES and fixed up dependencies.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/Kconfig

@@ -27,5 +27,12 @@ config KPROBES
 	  for kernel debugging, non-intrusive instrumentation and testing.
 	  If in doubt, say "N".
 
+config KRETPROBES
+	def_bool y
+	depends on KPROBES && HAVE_KRETPROBES
+
 config HAVE_KPROBES
 	def_bool n
+
+config HAVE_KRETPROBES
+	def_bool n

arch/arm/Kconfig

@@ -12,6 +12,7 @@ config ARM
 	select SYS_SUPPORTS_APM_EMULATION
 	select HAVE_OPROFILE
 	select HAVE_KPROBES if (!XIP_KERNEL)
+	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	help
 	  The ARM series is a line of low-power-consumption RISC chip designs
 	  licensed by ARM Ltd and targeted at embedded applications and

arch/ia64/Kconfig

@@ -18,6 +18,7 @@ config IA64
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to

arch/powerpc/Kconfig

@@ -90,6 +90,7 @@ config PPC
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 
 config EARLY_PRINTK
 	bool

arch/s390/Kconfig

@@ -61,6 +61,7 @@ config S390
 	def_bool y
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 
 source "init/Kconfig"
 

arch/sparc64/Kconfig

@@ -10,6 +10,7 @@ config SPARC
 	default y
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 
 config SPARC64
 	bool

arch/x86/Kconfig

@@ -21,6 +21,7 @@ config X86
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
+	select HAVE_KRETPROBES
 	select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)