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Subject[PATCH v2 12/13] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID
Date
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>
---
drivers/hwtracing/coresight/coresight-etm-perf.c | 10 ++++++++++
include/linux/coresight-pmu.h | 14 ++++++++++++++
2 files changed, 24 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index ad3fdc07c60b..531f5d42272b 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>
@@ -437,6 +438,7 @@ 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;
@@ -482,6 +484,11 @@ 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_get_cpu_id(cpu));
+ perf_report_aux_output_id(event, hw_id);
+
out:
/* Tell the perf core the event is alive */
event->hw.state = 0;
@@ -600,6 +607,9 @@ static void etm_event_stop(struct perf_event *event, int mode)

/* Disabling the path make its elements available to other sessions */
coresight_disable_path(path);
+
+ /* release the trace ID we read on event start */
+ coresight_trace_id_put_cpu_id(cpu);
}

static int etm_event_add(struct perf_event *event, int mode)
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 9f7ee380266b..5572d0e10822 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"

/*
@@ -38,4 +40,16 @@
#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.
+ * [63:16] - unused SBZ
+ * [15:08] - Trace ID
+ * [07:00] - Version
+ */
+#define CS_AUX_HW_ID_VERSION_MASK GENMASK_ULL(7, 0)
+#define CS_AUX_HW_ID_TRACE_ID_MASK GENMASK_ULL(15, 8)
+
+#define CS_AUX_HW_ID_CURR_VERSION 0
+
#endif
--
2.17.1
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