From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: James Clark <james.clark@arm.com>,
mathieu.poirier@linaro.org, coresight@lists.linaro.org
Cc: Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>,
John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 2/3] coresight: Fail to open with return stacks if they are unavailable
Date: Thu, 9 Dec 2021 11:00:40 +0000 [thread overview]
Message-ID: <b52ef2f3-9e30-59a6-2aea-e46c93915868@arm.com> (raw)
In-Reply-To: <20211208160907.749482-2-james.clark@arm.com>
On 08/12/2021 16:09, James Clark 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@arm.com>
> ---
> 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 d2bafb50c66a..0a9bb943a5e5 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);
> + }
nit: While at this, please could you change the hard coded value
to ETM4_CFG_BIT_RETSTK ?
Otherwise, looks good to me
Suzuki
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next prev parent reply other threads:[~2021-12-09 11:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 16:09 [PATCH 1/3] coresight: Add config flag to enable branch broadcast James Clark
2021-12-08 16:09 ` [PATCH 2/3] coresight: Fail to open with return stacks if they are unavailable James Clark
2021-12-09 11:00 ` Suzuki K Poulose [this message]
2021-12-09 11:13 ` James Clark
2021-12-10 17:22 ` Mathieu Poirier
2021-12-13 9:48 ` Mike Leach
2021-12-17 9:40 ` James Clark
2021-12-17 11:52 ` Mike Leach
2022-01-13 9:08 ` James Clark
2021-12-13 14:23 ` James Clark
2022-01-07 15:10 ` James Clark
2022-01-12 9:46 ` Suzuki K Poulose
2021-12-08 16:09 ` [PATCH 3/3] perf cs-etm: Update deduction of TRCCONFIGR register for branch broadcast James Clark
2021-12-10 2:41 ` Leo Yan
2022-01-13 9:09 ` James Clark
2021-12-09 9:21 ` [PATCH 1/3] coresight: Add config flag to enable " Suzuki K Poulose
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