x86/mm/pkeys: Add Kconfig option

I don't have a strong opinion on whether we need a Kconfig prompt
or not.  Protection Keys has relatively little code associated
with it, and it is not a heavyweight feature to keep enabled.
However, I can imagine that folks would still appreciate being
able to disable it.

Note that, with disabled-features.h, the checks in the code
for protection keys are always the same:

	cpu_has(c, X86_FEATURE_PKU)

With the config option disabled, this essentially turns into an

We will hide the prompt for now.

Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ab2ed5328f0a87c976a7fbbea31cc018d4a9c29d..3632cdd03201bf1b1b6fb50b95084917b09000da 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1714,6 +1714,10 @@ config X86_INTEL_MPX
 
          If unsure, say N.
 
+config X86_INTEL_MEMORY_PROTECTION_KEYS
+       def_bool y
+       depends on CPU_SUP_INTEL && X86_64
+
 config EFI
        bool "EFI runtime service support"
        depends on ACPI