[PATCH v3 12/13] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID

From: Mike Leach
Date: Tue Aug 09 2022 - 18:35:21 EST


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@xxxxxxxxxx>
---
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 6166f716a6ac..59a2ad95c1dc 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@xxxxxxxxxx>
*/

+#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) |
+ 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 99bc3cc6bf2d..9aafafff219a 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"

/*
@@ -44,4 +46,16 @@
#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