Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 170/496] clocksource/drivers/mips-gic-timer: Use correct shift count to extract data | Date | Mon, 28 May 2018 11:59:15 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Felix Fietkau <nbd@nbd.name>
[ Upstream commit 5753405e27f8fe4c42c1537d3ddbd9e058e54cdc ]
__gic_clocksource_init() extracts the GIC_CONFIG_COUNTBITS field from read_gic_config() by right shifting the register value. The shift count is determined by the most significant bit (__fls) of the bitmask which is wrong as it shifts out the complete bitfield.
Use the least significant bit (__ffs) instead to shift the bitfield down to bit 0.
Fixes: e07127a077c7 ("clocksource: mips-gic-timer: Use new GIC accessor functions") Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: paul.burton@imgtec.com Link: https://lkml.kernel.org/r/20180228095610.50341-1-nbd@nbd.name Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/clocksource/mips-gic-timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/clocksource/mips-gic-timer.c +++ b/drivers/clocksource/mips-gic-timer.c @@ -164,7 +164,7 @@ static int __init __gic_clocksource_init /* 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);
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