2 files changed, 12 insertions, 5 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 24ff26a38ade..5fff00c70de0 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -4,6 +4,7 @@
 #include <linux/string.h>
 #include <linux/bitops.h>
 #include <linux/smp.h>
+#include <linux/sched.h>
 #include <linux/thread_info.h>
 #include <linux/module.h>
 
@@ -56,11 +57,16 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
 
         /*
          * c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
-         * with P/T states and does not stop in deep C-states
+         * with P/T states and does not stop in deep C-states.
+         *
+         * It is also reliable across cores and sockets. (but not across
+         * cabinets - we turn it off in that case explicitly.)
          */
         if (c->x86_power & (1 << 8)) {
                 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
                 set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
+                set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
+                sched_clock_stable = 1;
         }
 
 }
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index b8e7aaf7ef75..08afa1579e6d 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -17,20 +17,21 @@
 #include <asm/delay.h>
 #include <asm/hypervisor.h>
 
-unsigned int cpu_khz;           /* TSC clocks / usec, not used here */
+unsigned int __read_mostly cpu_khz;     /* TSC clocks / usec, not used here */
 EXPORT_SYMBOL(cpu_khz);
-unsigned int tsc_khz;
+
+unsigned int __read_mostly tsc_khz;
 EXPORT_SYMBOL(tsc_khz);
 
 /*
  * TSC can be unstable due to cpufreq or due to unsynced TSCs
  */
-static int tsc_unstable;
+static int __read_mostly tsc_unstable;
 
 /* native_sched_clock() is called before tsc_init(), so
    we must start with the TSC soft disabled to prevent
    erroneous rdtsc usage on !cpu_has_tsc processors */
-static int tsc_disabled = -1;
+static int __read_mostly tsc_disabled = -1;
 
 static int tsc_clocksource_reliable;
 /*