[PATCH v6 13/14] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID

From: Mike Leach <mike.leach@linaro.org>
To: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: mathieu.poirier@linaro.org, suzuki.poulose@arm.com,
	peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	linux-perf-users@vger.kernel.org, leo.yan@linaro.org,
	quic_jinlmao@quicinc.com, Mike Leach <mike.leach@linaro.org>
Subject: [PATCH v6 13/14] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID
Date: Wed, 23 Nov 2022 19:50:09 +0000	[thread overview]
Message-ID: <20221123195010.6859-14-mike.leach@linaro.org> (raw)
In-Reply-To: <20221123195010.6859-1-mike.leach@linaro.org>

Use the perf_report_aux_output_id() call to output the CoreSight trace ID
and associated CPU as a PERF_RECORD_AUX_OUTPUT_HW_ID record in the
perf.data file.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c |  7 +++++++
 include/linux/coresight-pmu.h                    | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index bdb9ab86173a..12fff661456e 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -4,6 +4,7 @@
  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
  */
 
+#include <linux/bitfield.h>
 #include <linux/coresight.h>
 #include <linux/coresight-pmu.h>
 #include <linux/cpumask.h>
@@ -448,6 +449,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 	struct perf_output_handle *handle = &ctxt->handle;
 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
 	struct list_head *path;
+	u64 hw_id;
 
 	if (!csdev)
 		goto fail;
@@ -493,6 +495,11 @@ static void etm_event_start(struct perf_event *event, int flags)
 	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
 		goto fail_disable_path;
 
+	/* output cpu / trace ID in perf record */
+	hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, CS_AUX_HW_ID_CURR_VERSION);
+	hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, coresight_trace_id_read_cpu_id(cpu));
+	perf_report_aux_output_id(event, hw_id);
+
 out:
 	/* Tell the perf core the event is alive */
 	event->hw.state = 0;
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 624f4843453e..51ac441a37c3 100644
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -7,6 +7,8 @@
 #ifndef _LINUX_CORESIGHT_PMU_H
 #define _LINUX_CORESIGHT_PMU_H
 
+#include <linux/bits.h>
+
 #define CORESIGHT_ETM_PMU_NAME "cs_etm"
 
 /*
@@ -43,4 +45,16 @@
 #define ETM4_CFG_BIT_RETSTK	12
 #define ETM4_CFG_BIT_VMID_OPT	15
 
+/*
+ * Interpretation of the PERF_RECORD_AUX_OUTPUT_HW_ID payload.
+ * Used to associate a CPU with the CoreSight Trace ID.
+ * [07:00] - Trace ID - uses 8 bits to make value easy to read in file.
+ * [59:08] - Unused (SBZ)
+ * [63:60] - Version
+ */
+#define CS_AUX_HW_ID_TRACE_ID_MASK	GENMASK_ULL(7, 0)
+#define CS_AUX_HW_ID_VERSION_MASK	GENMASK_ULL(63, 60)
+
+#define CS_AUX_HW_ID_CURR_VERSION 0
+
 #endif
-- 
2.17.1

