Cross Memory Attach: make it Kconfigurable

Add a Kconfig option to allow people who don't want cross memory attach to
not have it included in their build.

Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/Kconfig b/mm/Kconfig
index 3922002..b217637 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -349,6 +349,16 @@
 	  benefit.
 endchoice
 
+config CROSS_MEMORY_ATTACH
+	bool "Cross Memory Support"
+	depends on MMU
+	default y
+	help
+	  Enabling this option adds the system calls process_vm_readv and
+	  process_vm_writev which allow a process with the correct privileges
+	  to directly read from or write to to another process's address space.
+	  See the man page for more details.
+
 #
 # UP and nommu archs use km based percpu allocator
 #