Re: [PATCH v12 02/14] coresight: etm4x: prohibit modifying cntr_val while session is enabled

[Mike Leach <mike.leach@arm.com>]

Reviewed-by: Mike Leach <mike.leach@arm.com>

On 9/24/26 18:33, Yeoreum Yun wrote:
> cntr_val is overwritten with the values read from the corresponding
> registers by etm4_disable_hw() when the session is disabled.
> 
> This means that any changes to these values made while the session is
> enabled would be lost when the session is disabled.
> 
> Therefore, prohibit modifying cntr_val while the session is enabled.
> 
> Tested-by: Leo Yan <leo.yan@arm.com>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>   drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index db3cf4ad6806..a547de5a3f9c 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -1615,6 +1615,9 @@ static ssize_t cntr_val_store(struct device *dev,
>   		return -EINVAL;
>   	if (val > ETM_CNTR_MAX_VAL)
>   		return -EINVAL;
> +	if (IS_ERR_OR_NULL(drvdata->csdev) ||
> +	    coresight_get_mode(drvdata->csdev))
> +		return -EBUSY;
>   
>   	raw_spin_lock(&drvdata->spinlock);
>   	idx = config->cntr_idx;
>