x86/intel: Add common OPTDIFFs

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20190827195122.731530141@infradead.org

arch/x86/include/asm/intel-family.h

@@ -5,9 +5,6 @@
 /*
  * "Big Core" Processors (Branded as Core, Xeon, etc...)
  *
- * The "_X" parts are generally the EP and EX Xeons, or the
- * "Extreme" ones, like Broadwell-E, or Atom microserver.
- *
  * While adding a new CPUID for a new microarchitecture, add a new
  * group to keep logically sorted out in chronological order. Within
  * that group keep the CPUID for the variants sorted by model number.
@@ -21,9 +18,19 @@
  * MICROARCH	Is the code name for the micro-architecture for this core.
  *		N.B. Not the platform name.
  * OPTDIFF	If needed, a short string to differentiate by market segment.
- *		Exact strings here will vary over time. _DESKTOP, _MOBILE, and
- *		_X (short for Xeon server) should be used when they are
- *		appropriate.
+ *
+ *		Common OPTDIFFs:
+ *
+ *			- regular client parts
+ *		_L	- regular mobile parts
+ *		_G	- parts with extra graphics on
+ *		_X	- regular server parts
+ *		_D	- micro server parts
+ *
+ *		Historical OPTDIFFs:
+ *
+ *		_EP	- 2 socket server parts
+ *		_EX	- 4+ socket server parts
  *
  * The #define line may optionally include a comment including platform names.
  */
@@ -91,6 +98,8 @@
 
 #define INTEL_FAM6_ATOM_GOLDMONT	0x5C /* Apollo Lake */
 #define INTEL_FAM6_ATOM_GOLDMONT_D	0x5F /* Denverton */
+
+/* Note: the micro-architecture is "Goldmont Plus" */
 #define INTEL_FAM6_ATOM_GOLDMONT_PLUS	0x7A /* Gemini Lake */
 
 #define INTEL_FAM6_ATOM_TREMONT_D	0x86 /* Jacobsville */