From: tip-bot for Zhenzhong Duan <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org,
mingo@kernel.org, zhenzhong.duan@oracle.com
Subject: [tip:x86/timers] x86/tsc: Call check_system_tsc_reliable() before unsynchronized_tsc()
Date: Thu, 22 Jun 2017 07:03:51 -0700 [thread overview]
Message-ID: <tip-a1272dd5531b259bf7313ac7597a67362698038c@git.kernel.org> (raw)
In-Reply-To: <b1532ef7-cd9f-45f7-9f49-48dd2a5c2495@default>
Commit-ID: a1272dd5531b259bf7313ac7597a67362698038c
Gitweb: http://git.kernel.org/tip/a1272dd5531b259bf7313ac7597a67362698038c
Author: Zhenzhong Duan <zhenzhong.duan@oracle.com>
AuthorDate: Wed, 21 Jun 2017 01:23:37 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 22 Jun 2017 16:00:03 +0200
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
---
arch/x86/kernel/tsc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 714dfba..a316bdd 100644
--- 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();
}
prev parent reply other threads:[~2017-06-22 14:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 8:23 [PATCH RESEND] Calling check_system_tsc_reliable() before unsynchronized_tsc() Zhenzhong Duan
2017-06-22 13:56 ` Thomas Gleixner
2017-06-23 8:30 ` Zhenzhong Duan
2017-06-22 14:03 ` tip-bot for Zhenzhong Duan [this message]
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