Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/x86_64/kernel/tsc.c |   43 +++++++++++--------------------------
 1 files changed, 13 insertions(+), 30 deletions(-)

diff -puN arch/x86_64/kernel/tsc.c~time-x86_64-tsc-fixup-clocksource-changes arch/x86_64/kernel/tsc.c
--- a/arch/x86_64/kernel/tsc.c~time-x86_64-tsc-fixup-clocksource-changes
+++ a/arch/x86_64/kernel/tsc.c
@@ -46,13 +46,6 @@ static inline int check_tsc_unstable(voi
 {
 	return tsc_unstable;
 }
-
-void mark_tsc_unstable(void)
-{
-	tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
 #ifdef CONFIG_CPU_FREQ
 
 /* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
@@ -143,12 +136,6 @@ core_initcall(cpufreq_tsc);
 
 static int tsc_unstable = 0;
 
-void mark_tsc_unstable(void)
-{
-	tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
 /*
  * Make an educated guess if the TSC is trustworthy and synchronized
  * over all CPUs.
@@ -187,9 +174,6 @@ __setup("notsc", notsc_setup);
 
 
 /* clock source code: */
-
-static int tsc_update_callback(void);
-
 static cycle_t read_tsc(void)
 {
 	cycle_t ret = (cycle_t)get_cycles_sync();
@@ -200,25 +184,24 @@ static struct clocksource clocksource_ts
 	.name			= "tsc",
 	.rating			= 300,
 	.read			= read_tsc,
-	.mask			= (cycle_t)-1,
-	.mult			= 0, /* to be set */
+	.mask			= CLOCKSOURCE_MASK(64),
 	.shift			= 22,
-	.update_callback	= tsc_update_callback,
-	.is_continuous		= 1,
+	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |
+				  CLOCK_SOURCE_MUST_VERIFY,
 };
 
-static int tsc_update_callback(void)
+void mark_tsc_unstable(void)
 {
-	int change = 0;
-
-	/* check to see if we should switch to the safe clocksource: */
-	if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
-		clocksource_tsc.rating = 50;
-		clocksource_reselect();
-		change = 1;
+	if (!tsc_unstable) {
+		tsc_unstable = 1;
+		/* Change only the rating, when not registered */
+		if (clocksource_tsc.mult)
+			clocksource_change_rating(&clocksource_tsc, 0);
+		else
+			clocksource_tsc.rating = 0;
 	}
-	return change;
 }
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static int __init init_tsc_clocksource(void)
 {
@@ -226,7 +209,7 @@ static int __init init_tsc_clocksource(v
 		clocksource_tsc.mult = clocksource_khz2mult(cpu_khz,
 							clocksource_tsc.shift);
 		if (check_tsc_unstable())
-			clocksource_tsc.rating = 50;
+			clocksource_tsc.rating = 0;
 
 		return clocksource_register(&clocksource_tsc);
 	}
_