Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull clocksource fixes from Thomas Gleixner:
 "The recent addition of the early TSC clocksource breaks on machines
  which have an unstable TSC because in case that TSC is disabled, then
  the clocksource selection logic falls back to the early TSC which is
  obviously bogus.

  That also unearthed a few robustness issues in the clocksource
  derating code which are addressed as well"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Rework stale comment
  clocksource: Consistent de-rate when marking unstable
  x86/tsc: Fix mark_tsc_unstable()
  clocksource: Initialize cs->wd_list
  clocksource: Allow clocksource_mark_unstable() on unregistered clocksources
  x86/tsc: Always unregister clocksource_tsc_early

1 files changed, 11 insertions, 11 deletions

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 91e6da48cbb6..74392d9d51e0 100644
--- 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);
@@ -1244,7 +1242,7 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 
 	/* Don't bother refining TSC on unstable systems */
 	if (tsc_unstable)
-		return;
+		goto unreg;
 
 	/*
 	 * Since the work is started early in boot, we may be
@@ -1297,11 +1295,12 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 
 out:
 	if (tsc_unstable)
-		return;
+		goto unreg;
 
 	if (boot_cpu_has(X86_FEATURE_ART))
 		art_related_clocksource = &clocksource_tsc;
 	clocksource_register_khz(&clocksource_tsc, tsc_khz);
+unreg:
 	clocksource_unregister(&clocksource_tsc_early);
 }
 
@@ -1311,8 +1310,8 @@ static int __init init_tsc_clocksource(void)
 	if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz)
 		return 0;
 
-	if (check_tsc_unstable())
-		return 0;
+	if (tsc_unstable)
+		goto unreg;
 
 	if (tsc_clocksource_reliable)
 		clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
@@ -1328,6 +1327,7 @@ static int __init init_tsc_clocksource(void)
 		if (boot_cpu_has(X86_FEATURE_ART))
 			art_related_clocksource = &clocksource_tsc;
 		clocksource_register_khz(&clocksource_tsc, tsc_khz);
+unreg:
 		clocksource_unregister(&clocksource_tsc_early);
 		return 0;
 	}