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Commit 1c839a5a authored by Mathieu Poirier's avatar Mathieu Poirier Committed by Arnaldo Carvalho de Melo
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perf cs-etm: Configure timestamp generation in CPU-wide mode 



When operating in CPU-wide mode tracers need to generate timestamps in
order to correlate the code being traced on one CPU with what is executed
on other CPUs.

Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: default avatarLeo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190524173508.29044-3-mathieu.poirier@linaro.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3399ad9a

tools/perf/arch/arm/util/cs-etm.c

+57 −0
Original line number Diff line number Diff line
@@ -99,6 +99,54 @@ static int cs_etm_set_context_id(struct auxtrace_record *itr, 
	return err;

}



static int cs_etm_set_timestamp(struct auxtrace_record *itr,

				struct perf_evsel *evsel, int cpu)

{

	struct cs_etm_recording *ptr;

	struct perf_pmu *cs_etm_pmu;

	char path[PATH_MAX];

	int err = -EINVAL;

	u32 val;



	ptr = container_of(itr, struct cs_etm_recording, itr);

	cs_etm_pmu = ptr->cs_etm_pmu;



	if (!cs_etm_is_etmv4(itr, cpu))

		goto out;



	/* Get a handle on TRCIRD0 */

	snprintf(path, PATH_MAX, "cpu%d/%s",

		 cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);

	err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);



	/* There was a problem reading the file, bailing out */

	if (err != 1) {

		pr_err("%s: can't read file %s\n",

		       CORESIGHT_ETM_PMU_NAME, path);

		goto out;

	}



	/*

	 * TRCIDR0.TSSIZE, bit [28-24], indicates whether global timestamping

	 * is supported:

	 *  0b00000 Global timestamping is not implemented

	 *  0b00110 Implementation supports a maximum timestamp of 48bits.

	 *  0b01000 Implementation supports a maximum timestamp of 64bits.

	 */

	val &= GENMASK(28, 24);

	if (!val) {

		err = -EINVAL;

		goto out;

	}



	/* All good, let the kernel know */

	evsel->attr.config |= (1 << ETM_OPT_TS);

	err = 0;



out:

	return err;

}



static int cs_etm_set_option(struct auxtrace_record *itr,

			     struct perf_evsel *evsel, u32 option)

{
@@ -118,6 +166,11 @@ static int cs_etm_set_option(struct auxtrace_record *itr, 
			if (err)

				goto out;

			break;

		case ETM_OPT_TS:

			err = cs_etm_set_timestamp(itr, evsel, i);

			if (err)

				goto out;

			break;

		default:

			goto out;

		}
@@ -343,6 +396,10 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, 
		err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_CTXTID);

		if (err)

			goto out;



		err = cs_etm_set_option(itr, cs_etm_evsel, ETM_OPT_TS);

		if (err)

			goto out;

	}



	/* Add dummy event to keep tracking */