Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
On Thu, 13 Jan 2022 at 09:11, James Clark <james.clark@xxxxxxx> wrote:
>
> Maintain consistency with the other options by failing to open when they
> aren't supported. For example ETM_OPT_TS, ETM_OPT_CTXTID2 and the newly
> added ETM_OPT_BRANCH_BROADCAST all return with -EINVAL if they are
> requested but not supported by hardware.
>
> The consequence of not doing this is that the user may not be
> aware that they are not enabling the feature as it is silently disabled.
>
> Signed-off-by: James Clark <james.clark@xxxxxxx>
> ---
> drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 04669ecc0efa..a93c1a5fe045 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -674,10 +674,15 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
> }
>
> /* return stack - enable if selected and supported */
> - if ((attr->config & BIT(ETM_OPT_RETSTK)) && drvdata->retstack)
> - /* bit[12], Return stack enable bit */
> - config->cfg |= BIT(12);
> -
> + if (attr->config & BIT(ETM_OPT_RETSTK)) {
> + if (!drvdata->retstack) {
> + ret = -EINVAL;
> + goto out;
> + } else {
> + /* bit[12], Return stack enable bit */
> + config->cfg |= BIT(12);
> + }
> + }
> /*
> * Set any selected configuration and preset.
> *
> --
> 2.28.0
>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
