From: Yang Yingliang <yangyingliang@huawei.com>
To: <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Cc: Yang Yingliang <yangyingliang@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 1/2] clocksource: replace cycle_last validation with an equal way
Date: Tue, 27 Oct 2015 21:21:12 +0800 [thread overview]
Message-ID: <1445952073-7260-2-git-send-email-yangyingliang@huawei.com> (raw)
In-Reply-To: <1445952073-7260-1-git-send-email-yangyingliang@huawei.com>
Mask the cycle values before subtraction. So we can use this
validation while the clocksource mask is not 64-bits.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
kernel/time/timekeeping_internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timekeeping_internal.h b/kernel/time/timekeeping_internal.h
index 4ea005a..984f02e 100644
--- a/kernel/time/timekeeping_internal.h
+++ b/kernel/time/timekeeping_internal.h
@@ -15,7 +15,7 @@ extern void tk_debug_account_sleep_time(struct timespec64 *t);
#ifdef CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE
static inline cycle_t clocksource_delta(cycle_t now, cycle_t last, cycle_t mask)
{
- cycle_t ret = (now - last) & mask;
+ cycle_t ret = (now & mask) - (last & mask);
return (s64) ret > 0 ? ret : 0;
}
--
2.5.0
next prev parent reply other threads:[~2015-10-27 13:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-27 13:21 [PATCH 0/2] validate the delta of cycle_now and cycle_last on arm64 Yang Yingliang
2015-10-27 13:21 ` Yang Yingliang [this message]
2015-10-30 14:56 ` [PATCH 1/2] clocksource: replace cycle_last validation with an equal way Thomas Gleixner
2015-10-31 10:07 ` Yang Yingliang
2015-10-31 10:20 ` [PATCH resend] clocksource: modify the cycle_last validation to fit for non-64bit clocksourece mask Yang Yingliang
2015-12-19 15:03 ` [tip:timers/core] clocksource: Make clocksource validation work for all clocksources tip-bot for Yang Yingliang
2016-01-04 17:13 ` John Stultz
2015-10-27 13:21 ` [PATCH 2/2] arm64: validate the delta of cycle_now and cycle_last Yang Yingliang
2015-10-27 14:03 ` Mark Rutland
2015-10-28 1:33 ` Ding Tianhong
2015-10-29 7:36 ` Yang Yingliang
2015-10-29 8:31 ` Yang Yingliang
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