6.12-stable review patch. If anyone has any objections, please let me know.
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From: Jakob Hauser jahau@rocketmail.com
[ Upstream commit f1ee5483e40881d8ad5a63aa148b753b5c6a839b ]
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.
Additionally, in the calculation lines h[0], h[1] and h[2] the unsigned long integer divisor BIT(13) causes an unsigned division, shifting the left-hand side of the equation back and forth, possibly ending up in large positive values instead of negative values on 32-bit architectures.
To solve those two issues, declare a signed integer with a value of BIT(13).
There is another omission in the clamp line: clamp_val() returns a value and it's going nowhere here. Self-assign it to h[i] to make use of the clamp macro.
Finally, replace clamp_val() macro by clamp() because after changing the limits from type unsigned long integer to signed integer it's fine that way.
Link: https://lkml.kernel.org/r/11609b2243c295d65ab4d47e78c239d61ad6be75.173291481... Fixes: 65f79b501030 ("iio: magnetometer: yas530: Add YAS537 variant") Signed-off-by: Jakob Hauser jahau@rocketmail.com
Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202411230458.dhZwh3TT-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202411282222.oF0B4110-lkp@intel.com/ Reviewed-by: David Laight david.laight@aculab.com Acked-by: Jonathan Cameron Jonathan.Cameron@huawei.com Cc: Lars-Peter Clausen lars@metafoo.de Cc: Linus Walleij linus.walleij@linaro.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 65011a8598d33..c55a38650c0d4 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); + h[i] = clamp(h[i], -half_range, half_range - 1); + xy1y2[i] = h[i] + half_range; } }