x86/cpu, x86/mm/pkeys: Define new CR4 bit

There is a new bit in CR4 for enabling protection keys.  We
will actually enable it later in the series.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20160212210202.3CFC3DB2@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/uapi/asm/processor-flags.h

@@ -118,6 +118,8 @@
 #define X86_CR4_SMEP		_BITUL(X86_CR4_SMEP_BIT)
 #define X86_CR4_SMAP_BIT	21 /* enable SMAP support */
 #define X86_CR4_SMAP		_BITUL(X86_CR4_SMAP_BIT)
+#define X86_CR4_PKE_BIT		22 /* enable Protection Keys support */
+#define X86_CR4_PKE		_BITUL(X86_CR4_PKE_BIT)
 
 /*
  * x86-64 Task Priority Register, CR8