x86: tsc: Add support for new S3_NONSTOP feature

Add support for new S3_NONSTOP feature
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

arch/x86/kernel/tsc.c

@@ -768,7 +768,8 @@ static cycle_t read_tsc(struct clocksource *cs)
 
 static void resume_tsc(struct clocksource *cs)
 {
-	clocksource_tsc.cycle_last = 0;
+	if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
+		clocksource_tsc.cycle_last = 0;
 }
 
 static struct clocksource clocksource_tsc = {
@@ -939,6 +940,9 @@ static int __init init_tsc_clocksource(void)
 		clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
 	}
 
+	if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
+		clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
+
 	/*
 	 * Trust the results of the earlier calibration on systems
 	 * exporting a reliable TSC.