From 8e1488a46dcf73b1f1916d95421e303dbf773fb4 Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Wed, 24 Feb 2021 09:48:35 -0700
Subject: [PATCH 5/5] perf cs-etm: Detect pid in VMID for kernel running at EL2

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 CONTEXTIDR (Arm32)
or CONTEXTIDR_EL1 (Arm64) is invalid but we have a valid VMID.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Co-developed-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Al Grant <al.grant@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20210213113220.292229-6-leo.yan@linaro.org
Link: https://lore.kernel.org/r/20210224164835.3497311-7-mathieu.poirier@linaro.org
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 38 +++++++++++++++++--
 1 file changed, 34 insertions(+), 4 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 3f4bc4050477..4052c9ce6e2f 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -6,6 +6,7 @@
  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
  */
 
+#include <linux/coresight-pmu.h>
 #include <linux/err.h>
 #include <linux/list.h>
 #include <linux/zalloc.h>
@@ -491,13 +492,42 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,
 			const ocsd_generic_trace_elem *elem,
 			const uint8_t trace_chan_id)
 {
-	pid_t tid;
+	pid_t tid = -1;
+	static u64 pid_fmt;
+	int ret;
 
-	/* Ignore PE_CONTEXT packets that don't have a valid contextID */
-	if (!elem->context.ctxt_id_valid)
+	/*
+	 * As all the ETMs run at the same exception level, the system should
+	 * have the same PID format crossing CPUs.  So cache the PID format
+	 * and reuse it for sequential decoding.
+	 */
+	if (!pid_fmt) {
+		ret = cs_etm__get_pid_fmt(trace_chan_id, &pid_fmt);
+		if (ret)
+			return OCSD_RESP_FATAL_SYS_ERR;
+	}
+
+	/*
+	 * 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, Bit ETM_OPT_CTXTID2 is set in this case.
+	 */
+	switch (pid_fmt) {
+	case BIT(ETM_OPT_CTXTID):
+		if (elem->context.ctxt_id_valid)
+			tid = elem->context.context_id;
+		break;
+	case BIT(ETM_OPT_CTXTID2):
+		if (elem->context.vmid_valid)
+			tid = elem->context.vmid;
+		break;
+	default:
+		break;
+	}
+
+	if (tid == -1)
 		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;
 
-- 
2.32.0.rc1.229.g3e70b5a671-goog