4.4-stable review patch. If anyone has any objections, please let me know.
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From: Robert Lippert roblip@gmail.com
[ Upstream commit bd467e4eababe4c04272c1e646f066db02734c79 ]
Power values in the 100s of watt range can easily blow past 32bit math limits when processing everything in microwatts.
Use 64bit math instead to avoid these issues on common 32bit ARM BMC platforms.
Fixes: 442aba78728e ("hwmon: PMBus device driver") Signed-off-by: Robert Lippert rlippert@google.com Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hwmon/pmbus/pmbus_core.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)
--- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -20,6 +20,7 @@ */
#include <linux/kernel.h> +#include <linux/math64.h> #include <linux/module.h> #include <linux/init.h> #include <linux/err.h> @@ -476,8 +477,8 @@ static long pmbus_reg2data_linear(struct static long pmbus_reg2data_direct(struct pmbus_data *data, struct pmbus_sensor *sensor) { - long val = (s16) sensor->data; - long m, b, R; + s64 b, val = (s16)sensor->data; + s32 m, R;
m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -505,11 +506,12 @@ static long pmbus_reg2data_direct(struct R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val = div_s64(val + 5LL, 10L); /* round closest */ R++; }
- return (val - b) / m; + val = div_s64(val - b, m); + return clamp_val(val, LONG_MIN, LONG_MAX); }
/* @@ -629,7 +631,8 @@ static u16 pmbus_data2reg_linear(struct static u16 pmbus_data2reg_direct(struct pmbus_data *data, struct pmbus_sensor *sensor, long val) { - long m, b, R; + s64 b, val64 = val; + s32 m, R;
m = data->info->m[sensor->class]; b = data->info->b[sensor->class]; @@ -646,18 +649,18 @@ static u16 pmbus_data2reg_direct(struct R -= 3; /* Adjust R and b for data in milli-units */ b *= 1000; } - val = val * m + b; + val64 = val64 * m + b;
while (R > 0) { - val *= 10; + val64 *= 10; R--; } while (R < 0) { - val = DIV_ROUND_CLOSEST(val, 10); + val64 = div_s64(val64 + 5LL, 10L); /* round closest */ R++; }
- return val; + return (u16)clamp_val(val64, S16_MIN, S16_MAX); }
static u16 pmbus_data2reg_vid(struct pmbus_data *data,