In the function yas537_measure() there is a clamp_val() with limits of -BIT(13) and BIT(13) - 1. The input clamp value h[] is of type s32. The BIT() is of type unsigned long integer due to its define in include/vdso/bits.h. The lower limit -BIT(13) is recognized as -8192 but expressed as an unsigned long integer. The size of an unsigned long integer differs between 32-bit and 64-bit architectures. Converting this to type s32 may lead to undesired behavior. Declaring a signed integer with a value of BIT(13) allows to use it more specifically as a negative value on the lower clamp limit. While at it, replace all BIT(13) in the function yas537_measure() by the signed integer. Reported-by: kernel test robot <lkp@xxxxxxxxx> Closes: https://lore.kernel.org/oe-kbuild-all/202411230458.dhZwh3TT-lkp@xxxxxxxxx/ Fixes: 65f79b501030 ("iio: magnetometer: yas530: Add YAS537 variant") Cc: David Laight <david.laight@xxxxxxxxxx> Signed-off-by: Jakob Hauser <jahau@xxxxxxxxxxxxxx> --- The patch is based on torvalds/linux v6.12. The calculation lines h[0], h[1] and h[2] exceed the limit of 80 characters per line. In terms of readability I would prefer to keep it that way. --- drivers/iio/magnetometer/yamaha-yas530.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c index 65011a8598d3..938b35536e0d 100644 --- a/drivers/iio/magnetometer/yamaha-yas530.c +++ b/drivers/iio/magnetometer/yamaha-yas530.c @@ -372,6 +372,7 @@ static int yas537_measure(struct yas5xx *yas5xx, u16 *t, u16 *x, u16 *y1, u16 *y u8 data[8]; u16 xy1y2[3]; s32 h[3], s[3]; + int half_range = BIT(13); int i, ret; mutex_lock(&yas5xx->lock); @@ -406,13 +407,13 @@ static int yas537_measure(struct yas5xx *yas5xx, u16 *t, u16 *x, u16 *y1, u16 *y /* The second version of YAS537 needs to include calibration coefficients */ if (yas5xx->version == YAS537_VERSION_1) { for (i = 0; i < 3; i++) - s[i] = xy1y2[i] - BIT(13); - h[0] = (c->k * (128 * s[0] + c->a2 * s[1] + c->a3 * s[2])) / BIT(13); - h[1] = (c->k * (c->a4 * s[0] + c->a5 * s[1] + c->a6 * s[2])) / BIT(13); - h[2] = (c->k * (c->a7 * s[0] + c->a8 * s[1] + c->a9 * s[2])) / BIT(13); + s[i] = xy1y2[i] - half_range; + h[0] = (c->k * (128 * s[0] + c->a2 * s[1] + c->a3 * s[2])) / half_range; + h[1] = (c->k * (c->a4 * s[0] + c->a5 * s[1] + c->a6 * s[2])) / half_range; + h[2] = (c->k * (c->a7 * s[0] + c->a8 * s[1] + c->a9 * s[2])) / half_range; for (i = 0; i < 3; i++) { - clamp_val(h[i], -BIT(13), BIT(13) - 1); - xy1y2[i] = h[i] + BIT(13); + clamp_val(h[i], -half_range, half_range - 1); + xy1y2[i] = h[i] + half_range; } } -- 2.43.0
