ARM: 7816/1: CONFIG_KUSER_HELPERS: fix help text

Commit f6f91b0d9fd9 ("ARM: allow kuser helpers to be removed from the
vector page") introduced some help text for the CONFIG_KUSER_HELPERS
option which is rather contradictory.

Let's fix that, and improve it a little.

Cc: <stable@vger.kernel.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index db5c2cab8fda4251bb636aa5567afafe5cfdb406..cd2c88e7a8f7557bfe299a7a6b364c395a969428 100644 (file)
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -809,15 +809,18 @@ config KUSER_HELPERS
          the CPU type fitted to the system.  This permits binaries to be
          run on ARMv4 through to ARMv7 without modification.
 
+         See Documentation/arm/kernel_user_helpers.txt for details.
+
          However, the fixed address nature of these helpers can be used
          by ROP (return orientated programming) authors when creating
          exploits.
 
          If all of the binaries and libraries which run on your platform
          are built specifically for your platform, and make no use of
-         these helpers, then you can turn this option off.  However,
-         when such an binary or library is run, it will receive a SIGILL
-         signal, which will terminate the program.
+         these helpers, then you can turn this option off to hinder
+         such exploits. However, in that case, if a binary or library
+         relying on those helpers is run, it will receive a SIGILL signal,
+         which will terminate the program.
 
          Say N here only if you are absolutely certain that you do not
          need these helpers; otherwise, the safe option is to say Y.