perf: cs-etm: Support version 0.1 of HW_ID packets

v0.1 HW_ID packets have a new field that describes which sink each CPU
writes to. Use the sink ID to link trace ID maps to each other so that
mappings are shared wherever the sink is shared.

Also update the error message to show that overlapping IDs aren't an
error in per-thread mode, just not supported. In the future we can
use the CPU ID from the AUX records, or watch for changing sink IDs on
HW_ID packets to use the correct decoders.

Reviewed-by: Mike Leach <[e-mail]>
Signed-off-by: James Clark <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Alexandre Torgue <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: Ganapatrao Kulkarni <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Maxime Coquelin <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Suzuki Poulouse <[e-mail]>
Cc: Will Deacon <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: James Clark <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/include/linux/coresight-pmu.h

···
  * 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
+ * [39:08] - Sink ID - as reported in /sys/bus/event_source/devices/cs_etm/sinks/
+ *	      Added in minor version 1.
+ * [55:40] - Unused (SBZ)
+ * [59:56] - Minor Version - previously existing fields are compatible with
+ *	      all minor versions.
+ * [63:60] - Major Version - previously existing fields mean different things
+ *	      in new major versions.
  */
 #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_SINK_ID_MASK	GENMASK_ULL(39, 8)
 
-#define CS_AUX_HW_ID_CURR_VERSION 0
+#define CS_AUX_HW_ID_MINOR_VERSION_MASK	GENMASK_ULL(59, 56)
+#define CS_AUX_HW_ID_MAJOR_VERSION_MASK	GENMASK_ULL(63, 60)
+
+#define CS_AUX_HW_ID_MAJOR_VERSION 0
+#define CS_AUX_HW_ID_MINOR_VERSION 1
 
 #endif

tools/perf/util/cs-etm.c

···
 	struct cs_etm_traceid_queue **traceid_queues;
 	/* Conversion between traceID and metadata pointers */
 	struct intlist *traceid_list;
+	/*
+	 * Same as traceid_list, but traceid_list may be a reference to another
+	 * queue's which has a matching sink ID.
+	 */
+	struct intlist *own_traceid_list;
+	u32 sink_id;
 };
 
 static int cs_etm__process_timestamped_queues(struct cs_etm_auxtrace *etm);
···
 		      (queue_nr << 16 | trace_chan_id)
 #define TO_QUEUE_NR(cs_queue_nr) (cs_queue_nr >> 16)
 #define TO_TRACE_CHAN_ID(cs_queue_nr) (cs_queue_nr & 0x0000ffff)
+#define SINK_UNSET ((u32) -1)
 
 static u32 cs_etm__get_v7_protocol_version(u32 etmidr)
 {
···
 		int err;
 
 		if (curr_cpu_data[CS_ETM_CPU] != cpu_metadata[CS_ETM_CPU]) {
-			pr_err("CS_ETM: map mismatch between HW_ID packet CPU and Trace ID\n");
+			/*
+			 * With > CORESIGHT_TRACE_IDS_MAX ETMs, overlapping IDs
+			 * are expected (but not supported) in per-thread mode,
+			 * rather than signifying an error.
+			 */
+			if (etmq->etm->per_thread_decoding)
+				pr_err("CS_ETM: overlapping Trace IDs aren't currently supported in per-thread mode\n");
+			else
+				pr_err("CS_ETM: map mismatch between HW_ID packet CPU and Trace ID\n");
+
 			return -EINVAL;
 		}
 
···
 	 * the correct trace ID into the metadata for setting up decoders later.
 	 */
 	return cs_etm__metadata_set_trace_id(trace_chan_id, cpu_data);
+}
+
+static int cs_etm__process_trace_id_v0_1(struct cs_etm_auxtrace *etm, int cpu,
+					 u64 hw_id)
+{
+	struct cs_etm_queue *etmq = cs_etm__get_queue(etm, cpu);
+	int ret;
+	u64 *cpu_data;
+	u32 sink_id = FIELD_GET(CS_AUX_HW_ID_SINK_ID_MASK, hw_id);
+	u8 trace_id = FIELD_GET(CS_AUX_HW_ID_TRACE_ID_MASK, hw_id);
+
+	/*
+	 * Check sink id hasn't changed in per-cpu mode. In per-thread mode,
+	 * let it pass for now until an actual overlapping trace ID is hit. In
+	 * most cases IDs won't overlap even if the sink changes.
+	 */
+	if (!etmq->etm->per_thread_decoding && etmq->sink_id != SINK_UNSET &&
+	    etmq->sink_id != sink_id) {
+		pr_err("CS_ETM: mismatch between sink IDs\n");
+		return -EINVAL;
+	}
+
+	etmq->sink_id = sink_id;
+
+	/* Find which other queues use this sink and link their ID maps */
+	for (unsigned int i = 0; i < etm->queues.nr_queues; ++i) {
+		struct cs_etm_queue *other_etmq = etm->queues.queue_array[i].priv;
+
+		/* Different sinks, skip */
+		if (other_etmq->sink_id != etmq->sink_id)
+			continue;
+
+		/* Already linked, skip */
+		if (other_etmq->traceid_list == etmq->traceid_list)
+			continue;
+
+		/* At the point of first linking, this one should be empty */
+		if (!intlist__empty(etmq->traceid_list)) {
+			pr_err("CS_ETM: Can't link populated trace ID lists\n");
+			return -EINVAL;
+		}
+
+		etmq->own_traceid_list = NULL;
+		intlist__delete(etmq->traceid_list);
+		etmq->traceid_list = other_etmq->traceid_list;
+		break;
+	}
+
+	cpu_data = get_cpu_data(etm, cpu);
+	ret = cs_etm__insert_trace_id_node(etmq, trace_id, cpu_data);
+	if (ret)
+		return ret;
+
+	ret = cs_etm__metadata_set_trace_id(trace_id, cpu_data);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
 static int cs_etm__metadata_get_trace_id(u8 *trace_chan_id, u64 *cpu_metadata)
···
 
 	/* extract and parse the HW ID */
 	hw_id = event->aux_output_hw_id.hw_id;
-	version = FIELD_GET(CS_AUX_HW_ID_VERSION_MASK, hw_id);
+	version = FIELD_GET(CS_AUX_HW_ID_MAJOR_VERSION_MASK, hw_id);
 
 	/* check that we can handle this version */
-	if (version > CS_AUX_HW_ID_CURR_VERSION) {
+	if (version > CS_AUX_HW_ID_MAJOR_VERSION) {
 		pr_err("CS ETM Trace: PERF_RECORD_AUX_OUTPUT_HW_ID version %d not supported. Please update Perf.\n",
 		       version);
 		return -EINVAL;
···
 		return -EINVAL;
 	}
 
-	return cs_etm__process_trace_id_v0(etm, cpu, hw_id);
+	if (FIELD_GET(CS_AUX_HW_ID_MINOR_VERSION_MASK, hw_id) == 0)
+		return cs_etm__process_trace_id_v0(etm, cpu, hw_id);
+
+	return cs_etm__process_trace_id_v0_1(etm, cpu, hw_id);
 }
 
 void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
···
 	cs_etm_decoder__free(etmq->decoder);
 	cs_etm__free_traceid_queues(etmq);
 
-	/* First remove all traceID/metadata nodes for the RB tree */
-	intlist__for_each_entry_safe(inode, tmp, etmq->traceid_list)
-		intlist__remove(etmq->traceid_list, inode);
+	if (etmq->own_traceid_list) {
+		/* First remove all traceID/metadata nodes for the RB tree */
+		intlist__for_each_entry_safe(inode, tmp, etmq->own_traceid_list)
+			intlist__remove(etmq->own_traceid_list, inode);
 
-	/* Then the RB tree itself */
-	intlist__delete(etmq->traceid_list);
+		/* Then the RB tree itself */
+		intlist__delete(etmq->own_traceid_list);
+	}
 
 	free(etmq);
 }
···
 	 * has to be made for each packet that gets decoded, optimizing access
 	 * in anything other than a sequential array is worth doing.
 	 */
-	etmq->traceid_list = intlist__new(NULL);
+	etmq->traceid_list = etmq->own_traceid_list = intlist__new(NULL);
 	if (!etmq->traceid_list)
 		goto out_free;
 
···
 	etmq->queue_nr = queue_nr;
 	queue->cpu = queue_nr; /* Placeholder, may be reset to -1 in per-thread mode */
 	etmq->offset = 0;
+	etmq->sink_id = SINK_UNSET;
 
 	return 0;
 }