x86/cpufeatures: Enumerate Intel Hybrid Technology feature bit

Add feature enumeration to identify a processor with Intel Hybrid
Technology: one in which CPUs of more than one type are the same package.
On a hybrid processor, all CPUs support the same homogeneous (i.e.,
symmetric) instruction set. All CPUs enumerate the same features in CPUID.
Thus, software (user space and kernel) can run and migrate to any CPU in
the system as well as utilize any of the enumerated features without any
change or special provisions. The main difference among CPUs in a hybrid
processor are power and performance properties.

Signed-off-by: Ricardo Neri <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Reviewed-by: Len Brown <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

arch/x86/include/asm/cpufeatures.h

@@ -374,6 +374,7 @@
 #define X86_FEATURE_MD_CLEAR		(18*32+10) /* VERW clears CPU buffers */
 #define X86_FEATURE_TSX_FORCE_ABORT	(18*32+13) /* "" TSX_FORCE_ABORT */
 #define X86_FEATURE_SERIALIZE		(18*32+14) /* SERIALIZE instruction */
+#define X86_FEATURE_HYBRID_CPU		(18*32+15) /* "" This part has CPUs of more than one type */
 #define X86_FEATURE_TSXLDTRK		(18*32+16) /* TSX Suspend Load Address Tracking */
 #define X86_FEATURE_PCONFIG		(18*32+18) /* Intel PCONFIG */
 #define X86_FEATURE_ARCH_LBR		(18*32+19) /* Intel ARCH LBR */