[PATCH V2 3/6] x86/mce: Define 'SUCCOR' cpuid bit

[Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>]

SUCCOR stands for S/W UnCorrectable error COntainment and Recovery.
It indicates support for data poisoning in HW and deferred error
interrupts.

Add new bitfield in mce_vendor_flags for this.
We use this to verify prescence of deferred error interrupts
before we enable them in mce_amd.c

While at it, clarify comments in mce_vendor_flags to provide an
indication of usages of the bitfields.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
---
 arch/x86/include/asm/mce.h       | 17 +++++++++++++++--
 arch/x86/kernel/cpu/mcheck/mce.c |  3 ++-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 1f5a86d..ab0cdac 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -117,8 +117,21 @@ struct mca_config {
 };
 
 struct mce_vendor_flags {
-	__u64		overflow_recov	: 1, /* cpuid_ebx(80000007) */
-			__reserved_0	: 63;
+			/* Flags from cpuid_ebx(80000007) */
+
+			/*
+			 * overflow recovery cpuid bit indicates that overflow
+			 * conditions are not fatal
+			 */
+	__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;
 };
 extern struct mce_vendor_flags mce_flags;
 
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index e535533..6d218ac 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1639,7 +1639,8 @@ static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
 		break;
 	case X86_VENDOR_AMD:
 		mce_amd_feature_init(c);
-		mce_flags.overflow_recov = cpuid_ebx(0x80000007) & 0x1;
+		mce_flags.overflow_recov = !!(cpuid_ebx(0x80000007) & BIT(0));
+		mce_flags.succor	 = !!(cpuid_ebx(0x80000007) & BIT(1));
 		break;
 	default:
 		break;
-- 
1.9.1