habanalabs: avoid divide by zero in device utilization

Currently there is no verification whether the divisor is legal.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index 0e88396744a1e9bd4971b1cdd31fce414221ef99..b71303ba11d0e20396c192008877f3ab6d82934d 100644 (file)
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -987,11 +987,16 @@ static void device_late_fini(struct hl_device *hdev)
 
 int hl_device_utilization(struct hl_device *hdev, u32 *utilization)
 {
-       u64 max_power, curr_power, dc_power, dividend;
+       u64 max_power, curr_power, dc_power, dividend, divisor;
        int rc;
 
        max_power = hdev->max_power;
        dc_power = hdev->asic_prop.dc_power_default;
+       divisor = max_power - dc_power;
+       if (!divisor) {
+               dev_warn(hdev->dev, "device utilization is not supported\n");
+               return -EOPNOTSUPP;
+       }
        rc = hl_fw_cpucp_power_get(hdev, &curr_power);
 
        if (rc)
@@ -1000,7 +1005,7 @@ int hl_device_utilization(struct hl_device *hdev, u32 *utilization)
        curr_power = clamp(curr_power, dc_power, max_power);
 
        dividend = (curr_power - dc_power) * 100;
-       *utilization = (u32) div_u64(dividend, (max_power - dc_power));
+       *utilization = (u32) div_u64(dividend, divisor);
 
        return 0;
 }