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);