From: Sean Paul Date: Thu, 4 Oct 2018 19:24:04 +0000 (-0400) Subject: drm/msm: a5xx: Fix improper u64 division X-Git-Tag: v4.20-rc1~81^2~8^2~2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f926a2e1718edc28f59f1079ebb6832532810587;p=linux.git drm/msm: a5xx: 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: de0a3d094de0 drm/msm: re-factor devfreq code Cc: Sharat Masetty Signed-off-by: Sean Paul Signed-off-by: Rob Clark --- diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c index 40b4f8a0ae6d..eabe9252ae1e 100644 --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c @@ -1438,18 +1438,20 @@ static struct msm_ringbuffer *a5xx_active_ring(struct msm_gpu *gpu) static unsigned long a5xx_gpu_busy(struct msm_gpu *gpu) { - u64 busy_cycles; - unsigned long busy_time; + u64 busy_cycles, busy_time; busy_cycles = gpu_read64(gpu, REG_A5XX_RBBM_PERFCTR_RBBM_0_LO, REG_A5XX_RBBM_PERFCTR_RBBM_0_HI); - busy_time = (busy_cycles - gpu->devfreq.busy_cycles) / - (clk_get_rate(gpu->core_clk) / 1000000); + busy_time = (busy_cycles - gpu->devfreq.busy_cycles); + do_div(busy_time, (clk_get_rate(gpu->core_clk) / 1000000)); 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 = {