Module Name: src
Committed By: christos
Date: Thu Jun 27 00:37:35 UTC 2013
Modified Files:
src/sys/arch/x86/x86: tsc.c
Log Message:
detect a bad msr tsc and don't use it.
To generate a diff of this commit:
cvs rdiff -u -r1.30 -r1.31 src/sys/arch/x86/x86/tsc.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/x86/x86/tsc.c
diff -u src/sys/arch/x86/x86/tsc.c:1.30 src/sys/arch/x86/x86/tsc.c:1.31
--- src/sys/arch/x86/x86/tsc.c:1.30 Mon Aug 8 13:00:23 2011
+++ src/sys/arch/x86/x86/tsc.c Wed Jun 26 20:37:34 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: tsc.c,v 1.30 2011/08/08 17:00:23 jmcneill Exp $ */
+/* $NetBSD: tsc.c,v 1.31 2013/06/27 00:37:34 christos Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tsc.c,v 1.30 2011/08/08 17:00:23 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tsc.c,v 1.31 2013/06/27 00:37:34 christos Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -51,6 +51,7 @@ u_int tsc_get_timecount(struct timecount
uint64_t tsc_freq; /* exported for sysctl */
static int64_t tsc_drift_max = 250; /* max cycles */
static int64_t tsc_drift_observed;
+static bool tsc_good;
static volatile int64_t tsc_sync_val;
static volatile struct cpu_info *tsc_sync_cpu;
@@ -76,6 +77,7 @@ tsc_tc_init(void)
ci = curcpu();
safe = false;
tsc_freq = ci->ci_data.cpu_cc_freq;
+ tsc_good = (cpu_feature[0] & CPUID_MSR) != 0 && rdmsr(MSR_TSC) != 0;
if (cpu_vendor == CPUVENDOR_INTEL) {
/*
@@ -258,10 +260,12 @@ cpu_hascounter(void)
return cpu_feature[0] & CPUID_TSC;
}
+extern int cpu_msr_tsc;
+
uint64_t
cpu_counter_serializing(void)
{
- if (cpu_feature[0] & CPUID_MSR)
+ if (tsc_good)
return rdmsr(MSR_TSC);
else
return cpu_counter();
