x86/tsc: Call check_system_tsc_reliable() before unsynchronized_tsc()

tsc_clocksource_reliable is initialized in check_system_tsc_reliable(), but
it is checked in unsynchronized_tsc() which is called before the
initialization.

In practice that's not an issue because systems which mark the TSC
reliable have X86_FEATURE_CONSTANT_TSC set as well, which is evaluated
in unsynchronized_tsc() before tsc_clocksource_reliable.

Reorder the calls so initialization happens before usage.

[ tglx: Massaged changelog ]

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b1532ef7-cd9f-45f7-9f49-48dd2a5c2495@default

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 714dfba6a1e713fb6b5f4268c318f913bb266628..a316bdd42a379c661eae3dc69de9e689b6a7c2fd 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1412,11 +1412,11 @@ void __init tsc_init(void)
 
        use_tsc_delay();
 
+       check_system_tsc_reliable();
+
        if (unsynchronized_tsc())
                mark_tsc_unstable("TSCs unsynchronized");
 
-       check_system_tsc_reliable();
-
        detect_art();
 }