x86: unify stackprotector features

streamline the stackprotector features under a single option
and make the stronger feature the one accessible.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 83d8392c13340a9d7412a63ecc9a4d7be0ba9293..0cd1695c24fbf48cc231f9bc328073677e84aa2f 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1140,13 +1140,17 @@ config SECCOMP
 
          If unsure, say Y. Only embedded should say N here.
 
+config CC_STACKPROTECTOR_ALL
+       bool
+
 config CC_STACKPROTECTOR
        bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
        depends on X86_64
+       select CC_STACKPROTECTOR_ALL
        help
-         This option turns on the -fstack-protector GCC feature. This
-         feature puts, at the beginning of critical functions, a canary
-         value on the stack just before the return address, and validates
+          This option turns on the -fstack-protector GCC feature. This
+         feature puts, at the beginning of functions, a canary value on
+         the stack just before the return address, and validates
          the value just before actually returning.  Stack based buffer
          overflows (that need to overwrite this return address) now also
          overwrite the canary, which gets detected and the attack is then
@@ -1154,16 +1158,8 @@ config CC_STACKPROTECTOR
 
          This feature requires gcc version 4.2 or above, or a distribution
          gcc with the feature backported. Older versions are automatically
-         detected and for those versions, this configuration option is ignored.
-
-config CC_STACKPROTECTOR_ALL
-       bool "Use stack-protector for all functions"
-       depends on CC_STACKPROTECTOR
-       default y
-       help
-         Normally, GCC only inserts the canary value protection for
-         functions that use large-ish on-stack buffers. By enabling
-         this option, GCC will be asked to do this for ALL functions.
+         detected and for those versions, this configuration option is
+         ignored. (and a warning is printed during bootup)
 
 source kernel/Kconfig.hz