x86/tsc: Fix mark_tsc_unstable()

mark_tsc_unstable() also needs to affect tsc_early, Now that
clocksource_mark_unstable() can be used on a clocksource irrespective of
its registration state, use it on both tsc_early and tsc.

This does however require cs->list to be initialized empty, otherwise it
cannot tell the registation state before registation.

Fixes: aa83c45762a2 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Diego Viola <diego.viola@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180430100344.533326547@infradead.org

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 23f36bc236ba45edb7aba35289057b508b131b45..74392d9d51e0a799a7f4fcb974a55e7989ed400a 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1067,6 +1067,7 @@ static struct clocksource clocksource_tsc_early = {
        .resume                 = tsc_resume,
        .mark_unstable          = tsc_cs_mark_unstable,
        .tick_stable            = tsc_cs_tick_stable,
+       .list                   = LIST_HEAD_INIT(clocksource_tsc_early.list),
 };
 
 /*
@@ -1086,6 +1087,7 @@ static struct clocksource clocksource_tsc = {
        .resume                 = tsc_resume,
        .mark_unstable          = tsc_cs_mark_unstable,
        .tick_stable            = tsc_cs_tick_stable,
+       .list                   = LIST_HEAD_INIT(clocksource_tsc.list),
 };
 
 void mark_tsc_unstable(char *reason)
@@ -1098,13 +1100,9 @@ void mark_tsc_unstable(char *reason)
                clear_sched_clock_stable();
        disable_sched_clock_irqtime();
        pr_info("Marking TSC unstable due to %s\n", reason);
-       /* Change only the rating, when not registered */
-       if (clocksource_tsc.mult) {
-               clocksource_mark_unstable(&clocksource_tsc);
-       } else {
-               clocksource_tsc.flags |= CLOCK_SOURCE_UNSTABLE;
-               clocksource_tsc.rating = 0;
-       }
+
+       clocksource_mark_unstable(&clocksource_tsc_early);
+       clocksource_mark_unstable(&clocksource_tsc);
 }
 
 EXPORT_SYMBOL_GPL(mark_tsc_unstable);