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Date:      Mon, 11 Sep 2017 20:41:26 +0000 (UTC)
From:      Conrad Meyer <cem@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r323462 - head/sys/x86/x86
Message-ID:  <201709112041.v8BKfQbv020774@repo.freebsd.org>
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Author: cem
Date: Mon Sep 11 20:41:25 2017
New Revision: 323462
URL: https://svnweb.freebsd.org/changeset/base/323462

Log:
  x86 MCA: Extract CMCI support predicate into function
  
  On AMD, the MCG_CAP feature bit is reserved -- not explicitly zero.  Do not
  use it to determine CMCI support.
  
  Reviewed by:	avg, markj
  Sponsored by:	Dell EMC Isilon
  Differential Revision:	https://reviews.freebsd.org/D12320

Modified:
  head/sys/x86/x86/mca.c

Modified: head/sys/x86/x86/mca.c
==============================================================================
--- head/sys/x86/x86/mca.c	Mon Sep 11 20:33:20 2017	(r323461)
+++ head/sys/x86/x86/mca.c	Mon Sep 11 20:41:25 2017	(r323462)
@@ -149,6 +149,18 @@ amd_thresholding_supported(void)
 }
 #endif
 
+static inline bool
+cmci_supported(uint64_t mcg_cap)
+{
+	/*
+	 * MCG_CAP_CMCI_P bit is reserved in AMD documentation.  Until
+	 * it is defined, do not use it to check for CMCI support.
+	 */
+	if (cpu_vendor_id != CPU_VENDOR_INTEL)
+		return (false);
+	return ((mcg_cap & MCG_CAP_CMCI_P) != 0);
+}
+
 static int
 sysctl_positive_int(SYSCTL_HANDLER_ARGS)
 {
@@ -322,7 +334,7 @@ mca_log(const struct mca_record *rec)
 		printf("UNCOR ");
 	else {
 		printf("COR ");
-		if (rec->mr_mcg_cap & MCG_CAP_CMCI_P)
+		if (cmci_supported(rec->mr_mcg_cap))
 			printf("(%lld) ", ((long long)rec->mr_status &
 			    MC_STATUS_COR_COUNT) >> 38);
 	}
@@ -873,7 +885,7 @@ mca_setup(uint64_t mcg_cap)
 	    "force_scan", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0,
 	    sysctl_mca_scan, "I", "Force an immediate scan for machine checks");
 #ifdef DEV_APIC
-	if (mcg_cap & MCG_CAP_CMCI_P)
+	if (cmci_supported(mcg_cap))
 		cmci_setup();
 	else if (amd_thresholding_supported())
 		amd_thresholding_setup();
@@ -1104,7 +1116,7 @@ _mca_init(int boot)
 				wrmsr(MSR_MC_CTL(i), ctl);
 
 #ifdef DEV_APIC
-			if (mcg_cap & MCG_CAP_CMCI_P) {
+			if (cmci_supported(mcg_cap)) {
 				if (boot)
 					cmci_monitor(i);
 				else

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