x86/mm: add ARCH_PKEY_BITS to Kconfig

The new config option specifies how many bits are in each PKEY.

Signed-off-by: Joey Gouly <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: [email protected]
Acked-by: Dave Hansen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

Author: jgouly

arch/x86/Kconfig

@@ -1889,6 +1889,10 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
 
 	  If unsure, say y.
 
+config ARCH_PKEY_BITS
+	int
+	default 4
+
 choice
 	prompt "TSX enable mode"
 	depends on CPU_SUP_INTEL