From: Sean Paul Date: Mon, 8 Oct 2018 18:24:14 +0000 (-0400) Subject: drm/msm: a6xx: Fix improper u64 division X-Git-Tag: v4.20-rc1~81^2~7^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=16f37102181e23ec4bec88fe1cfdd6c3c24dd1ed;p=thirdparty%2Fkernel%2Flinux.git drm/msm: a6xx: Fix improper u64 division This patch uses the proper do_div() macro to perform u64 division and guards against overflow if the result is too large for the unsigned long return type Fixes: a2c3c0a54d4c drm/msm/a6xx: Add devfreq support for a6xx Cc: Sharat Masetty Signed-off-by: Sean Paul Signed-off-by: Rob Clark --- diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c index cdc3d59a659db..631257c297fd0 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c @@ -761,18 +761,21 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu) { struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu); struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu); - u64 busy_cycles; - unsigned long busy_time; + u64 busy_cycles, busy_time; busy_cycles = gmu_read64(&a6xx_gpu->gmu, REG_A6XX_GMU_CX_GMU_POWER_COUNTER_XOCLK_0_L, REG_A6XX_GMU_CX_GMU_POWER_COUNTER_XOCLK_0_H); - busy_time = ((busy_cycles - gpu->devfreq.busy_cycles) * 10) / 192; + busy_time = (busy_cycles - gpu->devfreq.busy_cycles) * 10; + do_div(busy_time, 192); gpu->devfreq.busy_cycles = busy_cycles; - return busy_time; + if (WARN_ON(busy_time > ~0LU)) + return ~0LU; + + return (unsigned long)busy_time; } static const struct adreno_gpu_funcs funcs = {