x86: disable TSC for sched_clock() when calibration failed

When the TSC calibration fails then TSC is still used in sched_clock(). Disable it completely in that case. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
mariux64 · May 23, 2008 · 74dc51a · 74dc51a
1 parent 9ccc906
commit 74dc51a
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c
@@ -413,6 +413,11 @@ void __init tsc_init(void)
 
 	if (!cpu_khz) {
 		mark_tsc_unstable("could not calculate TSC khz");
+		/*
+		 * We need to disable the TSC completely in this case
+		 * to prevent sched_clock() from using it.
+		 */
+		tsc_disabled = 1;
 		return;
 	}