From 31ec38ec9cd523e9448163962cdaae2c7f2662b5 Mon Sep 17 00:00:00 2001 From: Dien Pham Date: Thu, 25 Jun 2020 20:38:19 +0900 Subject: [PATCH] thermal/drivers/rcar_gen3: Fix undefined temperature if negative [ Upstream commit 5f8f06425a0dcdad7bedbb77e67f5c65ab4dacfc ] As description for DIV_ROUND_CLOSEST in file include/linux/kernel.h. "Result is undefined for negative divisors if the dividend variable type is unsigned and for negative dividends if the divisor variable type is unsigned." In current code, the FIXPT_DIV uses DIV_ROUND_CLOSEST but has not checked sign of divisor before using. It makes undefined temperature value in case the value is negative. This patch fixes to satisfy DIV_ROUND_CLOSEST description and fix bug too. Note that the variable name "reg" is not good because it should be the same type as rcar_gen3_thermal_read(). However, it's better to rename the "reg" in a further patch as cleanup. Signed-off-by: Van Do Signed-off-by: Dien Pham [shimoda: minor fixes, add Fixes tag] Fixes: 564e73d283af ("thermal: rcar_gen3_thermal: Add R-Car Gen3 thermal driver") Signed-off-by: Yoshihiro Shimoda Reviewed-by: Niklas Soderlund Tested-by: Niklas Soderlund Reviewed-by: Amit Kucheria Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/1593085099-2057-1-git-send-email-yoshihiro.shimoda.uh@renesas.com Signed-off-by: Sasha Levin --- drivers/thermal/rcar_gen3_thermal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c index 755d2b5bd2c2..1ab2ffff4e7c 100644 --- a/drivers/thermal/rcar_gen3_thermal.c +++ b/drivers/thermal/rcar_gen3_thermal.c @@ -169,7 +169,7 @@ static int rcar_gen3_thermal_get_temp(void *devdata, int *temp) { struct rcar_gen3_thermal_tsc *tsc = devdata; int mcelsius, val; - u32 reg; + int reg; /* Read register and convert to mili Celsius */ reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;