Commit 8309f86c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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x86/tsc: Provide 'tsc=unstable' boot parameter

Since the clocksource watchdog will only detect broken TSC after the
fact, all TSC based clocks will likely have observed non-continuous
values before/when switching away from TSC.

Therefore only thing to fully avoid random clock movement when your
BIOS randomly mucks with TSC values from SMI handlers is reporting the
TSC as unstable at boot.
Signed-off-by: default avatarPeter Zijlstra (Intel) <>
Cc: Linus Torvalds <>
Cc: Mike Galbraith <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>
Signed-off-by: default avatarIngo Molnar <>
parent 625ed2bf
......@@ -374,6 +374,8 @@ static int __init tsc_setup(char *str)
tsc_clocksource_reliable = 1;
if (!strncmp(str, "noirqtime", 9))
no_sched_irq_time = 1;
if (!strcmp(str, "unstable"))
mark_tsc_unstable("boot parameter");
return 1;
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