[PATCH v5 02/12] coresight: etm4x: fix underflow for nrseqstate

[Suzuki K Poulose]

On 16/04/2026 16:11, Leo Yan wrote:
> On Wed, Apr 15, 2026 at 05:55:18PM +0100, Yeoreum Yun wrote:
>> TCRSEQEVR<n> is implemented only when TCRIDR5.NUMSEQSTATE is 0b100,
>> in which case n ranges from 0 to 2; otherwise, TCRIDR5.NUMSEQSTATE is 0b000.
> 
> My suggestion in previous version is not quite right, thanks for
> making this correct.
> 
> [...]
> 
>> @@ -1395,6 +1395,8 @@ static ssize_t seq_idx_store(struct device *dev,
>>   	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
>>   	struct etmv4_config *config = &drvdata->config;
>>   
>> +	if (!drvdata->nrseqstate)
>> +		return -EINVAL;
> 
> For "nrseqstate = 0" case, would it return -EOPNOTSUPP instead?

Or should we make this only visible if the nrseqstore is meaningful ?

Suzuki

> 
> Otherwise, LGTM:
> 
> Reviewed-by: Leo Yan <leo.yan at arm.com>