make /dev/kmem a config option

Make /dev/kmem a config option; /dev/kmem is VERY rarely used, and when
used, it's generally for no good (rootkits tend to be the most common
users).  With this config option, users have the choice to disable
/dev/kmem, saving some size as well.

A patch to disable /dev/kmem has been in the Fedora and RHEL kernels for
4+ years now without any known problems or legit users of /dev/kmem.

[akpm@linux-foundation.org: make CONFIG_DEVKMEM default to y]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 929d4fa73fd9..5dce3877eee5 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -80,6 +80,15 @@ config VT_HW_CONSOLE_BINDING
          information. For framebuffer console users, please refer to
          <file:Documentation/fb/fbcon.txt>.
 
+config DEVKMEM
+        bool "/dev/kmem virtual device support"
+        default y
+        help
+          Say Y here if you want to support the /dev/kmem device. The
+          /dev/kmem device is rarely used, but can be used for certain
+          kind of kernel debugging operations.
+          When in doubt, say "N".
+
 config SERIAL_NONSTANDARD
         bool "Non-standard serial port support"
         depends on HAS_IOMEM