[PATCH 3/3] rfc: perf: cs_etm: Detect pid in VMID for kernel running at EL2

[Suzuki K Poulose]

The pid of the task could be traced as VMID when the kernel is
running at EL2. Teach the decoder to look for vmid when the
context_id is invalid but we have a valid VMID.

Cc: Mike Leach <mike.leach at linaro.org>
Cc: Leo Yan <leo.yan at linaro.org>
Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---

Ideally, we should also confirm that the VMID_OPT is also set
in the trcconfigr for choosing the VMID. Hence the RFC. May be
that is something we could cache in the "decoder" instance ?
---
 .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 28 +++++++++++--------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index cd007cc9c283..31ba7ff57914 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -502,19 +502,25 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,
 {
 	pid_t tid;
 
-	/* Ignore PE_CONTEXT packets that don't have a valid contextID */
-	if (!elem->context.ctxt_id_valid)
-		return OCSD_RESP_CONT;
-
-	tid =  elem->context.context_id;
-	if (cs_etm__etmq_set_tid(etmq, tid, trace_chan_id))
-		return OCSD_RESP_FATAL_SYS_ERR;
-
 	/*
-	 * A timestamp is generated after a PE_CONTEXT element so make sure
-	 * to rely on that coming one.
+	 * Process the PE_CONTEXT packets if we have a valid
+	 *  contextID or VMID.
+	 * If the kernel is running at EL2, the PID is traced
+	 * in contextidr_el2 as VMID.
 	 */
-	cs_etm_decoder__reset_timestamp(packet_queue);
+	if (elem->context.ctxt_id_valid || elem->context.vmid_valid) {
+		if (elem->context.ctxt_id_valid)
+			tid =  elem->context.context_id;
+		else
+			tid = elem->context.vmid;
+		if (cs_etm__etmq_set_tid(etmq, tid, trace_chan_id))
+			return OCSD_RESP_FATAL_SYS_ERR;
+		/*
+		 * A timestamp is generated after a PE_CONTEXT element so make sure
+		 * to rely on that coming one.
+		 */
+		cs_etm_decoder__reset_timestamp(packet_queue);
+	}
 
 	return OCSD_RESP_CONT;
 }
-- 
2.24.1