x86/Kconfig: Update config and kernel doc for MPK feature on AMD

AMD's next generation of EPYC processors support the MPK (Memory
Protection Keys) feature. Update the dependency and documentation.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/159068199556.26992.17733929401377275140.stgit@naples-babu.amd.com

Documentation/core-api/protection-keys.rst

@@ -5,8 +5,9 @@ Memory Protection Keys
 ======================
 
 Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
-which is found on Intel's Skylake "Scalable Processor" Server CPUs.
-It will be avalable in future non-server parts.
+which is found on Intel's Skylake (and later) "Scalable Processor"
+Server CPUs. It will be available in future non-server Intel parts
+and future AMD processors.
 
 For anyone wishing to test or use this feature, it is available in
 Amazon's EC2 C5 instances and is known to work there using an Ubuntu

arch/x86/Kconfig

@@ -1887,10 +1887,10 @@ config X86_UMIP
 	  results are dummy.
 
 config X86_INTEL_MEMORY_PROTECTION_KEYS
-	prompt "Intel Memory Protection Keys"
+	prompt "Memory Protection Keys"
 	def_bool y
 	# Note: only available in 64-bit mode
-	depends on CPU_SUP_INTEL && X86_64
+	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
 	select ARCH_USES_HIGH_VMA_FLAGS
 	select ARCH_HAS_PKEYS
 	---help---