linux-kernel - [PATCH v2] clocksource: mips-gic-timer: fix clocksource counter width

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Date:   Wed, 28 Feb 2018 10:56:10 +0100
From:   Felix Fietkau <nbd@....name>
To:     linux-kernel@...r.kernel.org
Cc:     daniel.lezcano@...aro.org, paul.burton@...tec.com,
        tglx@...utronix.de
Subject: [PATCH v2] clocksource: mips-gic-timer: fix clocksource counter width

This code is trying to extract the GIC_CONFIG_COUNTBITS field from
read_gic_config(), so it needs to shift count_width right by the index
of the least significant bit (__ffs) instead of the most significant bit
(__fls) of the field mask.

Fixes: e07127a077c7 ("clocksource: mips-gic-timer: Use new GIC accessor functions")
Cc: Paul Burton <paul.burton@...tec.com>
Cc: stable@...r.kernel.org
Signed-off-by: Felix Fietkau <nbd@....name>
---
 drivers/clocksource/mips-gic-timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index a04808a21d4e..bf0eee78c6ef 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -166,7 +166,7 @@ static int __init __gic_clocksource_init(void)
 
 	/* Set clocksource mask. */
 	count_width = read_gic_config() & GIC_CONFIG_COUNTBITS;
-	count_width >>= __fls(GIC_CONFIG_COUNTBITS);
+	count_width >>= __ffs(GIC_CONFIG_COUNTBITS);
 	count_width *= 4;
 	count_width += 32;
 	gic_clocksource.mask = CLOCKSOURCE_MASK(count_width);
-- 
2.14.2