linux-kernel - [PATCH v2 07/13] coresight: perf: traceid: Add perf notifiers for Trace ID

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Message-Id: <20220704081149.16797-8-mike.leach@linaro.org>
Date:   Mon,  4 Jul 2022 09:11:43 +0100
From:   Mike Leach <mike.leach@...aro.org>
To:     suzuki.poulose@....com, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     mathieu.poirier@...aro.org, peterz@...radead.org, mingo@...hat.com,
        acme@...nel.org, linux-perf-users@...r.kernel.org,
        leo.yan@...aro.org, quic_jinlmao@...cinc.com,
        Mike Leach <mike.leach@...aro.org>
Subject: [PATCH v2 07/13] coresight: perf: traceid: Add perf notifiers for Trace ID

Adds in notifier calls to the trace ID allocator that perf
events are starting and stopping.

This ensures that Trace IDs associated with CPUs remain the same
throughout the perf session, and are only released when all perf
sessions are complete.

Signed-off-by: Mike Leach <mike.leach@...aro.org>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c039b6ae206f..ad3fdc07c60b 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -22,6 +22,7 @@
 #include "coresight-etm-perf.h"
 #include "coresight-priv.h"
 #include "coresight-syscfg.h"
+#include "coresight-trace-id.h"
 
 static struct pmu etm_pmu;
 static bool etm_perf_up;
@@ -228,6 +229,9 @@ static void free_event_data(struct work_struct *work)
 		*ppath = NULL;
 	}
 
+	/* mark perf event as done for trace id allocator */
+	coresight_trace_id_perf_stop();
+
 	free_percpu(event_data->path);
 	kfree(event_data);
 }
@@ -314,6 +318,9 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 		sink = user_sink = coresight_get_sink_by_id(id);
 	}
 
+	/* tell the trace ID allocator that a perf event is starting up */
+	coresight_trace_id_perf_start();
+
 	/* check if user wants a coresight configuration selected */
 	cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
 	if (cfg_hash) {
-- 
2.17.1