x86/mce: Add a Scalable MCA vendor flags bit

Scalable MCA (SMCA) is a new feature in AMD Fam17h processors
which indicates presence of MCA extensions.

MCA extensions expands existing register space for the MCE banks
and also introduces a new MSR range to accommodate new banks.

Add the detection bit.

Signed-off-by: Aravind Gopalakrishnan <[e-mail]>
[ Reformat mce_vendor_flags definitions and save indentation levels. Improve comments. ]
Signed-off-by: Borislav Petkov <[e-mail]>
Cc: Ashok Raj <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: linux-edac <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/include/asm/mce.h

···
 };
 
 struct mce_vendor_flags {
-			/*
-			 * overflow recovery cpuid bit indicates that overflow
-			 * conditions are not fatal
-			 */
-	__u64		overflow_recov	: 1,
+	/*
+	 * Indicates that overflow conditions are not fatal, when set.
+	 */
+	__u64 overflow_recov	: 1,
 
-			/*
-			 * SUCCOR stands for S/W UnCorrectable error COntainment
-			 * and Recovery. It indicates support for data poisoning
-			 * in HW and deferred error interrupts.
-			 */
-			succor		: 1,
-			__reserved_0	: 62;
+	/*
+	 * (AMD) SUCCOR stands for S/W UnCorrectable error COntainment and
+	 * Recovery. It indicates support for data poisoning in HW and deferred
+	 * error interrupts.
+	 */
+	      succor		: 1,
+
+	/*
+	 * (AMD) SMCA: This bit indicates support for Scalable MCA which expands
+	 * the register space for each MCA bank and also increases number of
+	 * banks. Also, to accommodate the new banks and registers, the MCA
+	 * register space is moved to a new MSR range.
+	 */
+	      smca		: 1,
+
+	      __reserved_0	: 61;
 };
 extern struct mce_vendor_flags mce_flags;
 

arch/x86/kernel/cpu/mcheck/mce.c

···
 		mce_amd_feature_init(c);
 		mce_flags.overflow_recov = !!(ebx & BIT(0));
 		mce_flags.succor	 = !!(ebx & BIT(1));
+		mce_flags.smca		 = !!(ebx & BIT(3));
+
 		break;
 		}