[PATCH v3 6/8] perf cs-etm: Add helper cs_etm__get_pid_fmt()

Leo Yan
2021-02-06T15:10:46Z

This patch adds helper function cs_etm__get_pid_fmt(), by passing
parameter "traceID", it returns the PID format.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/util/cs-etm.c | 42 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/cs-etm.h | 1 +
2 files changed, 43 insertions(+)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index a2a369e2fbb6..b9c1d329a7f1 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -7,6 +7,7 @@
*/

#include <linux/bitops.h>
+#include <linux/coresight-pmu.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/log2.h>
@@ -156,6 +157,47 @@ int cs_etm__get_cpu(u8 trace_chan_id, int *cpu)
return 0;
}

+/*
+ * The returned PID format is presented by two bits:
+ *
+ * Bit ETM_OPT_CTXTID: CONTEXTIDR or CONTEXTIDR_EL1 is traced;
+ * Bit ETM_OPT_CTXTID2: CONTEXTIDR_EL2 is traced.
+ *
+ * It's possible that the two bits ETM_OPT_CTXTID and ETM_OPT_CTXTID2
+ * are enabled at the same time when the session runs on an EL2 kernel.
+ * This means the CONTEXTIDR_EL1 and CONTEXTIDR_EL2 both will be
+ * recorded in the trace data, the tool will selectively use
+ * CONTEXTIDR_EL2 as PID.
+ */
+int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt)
+{
+ struct int_node *inode;
+ u64 *metadata, val;
+
+ inode = intlist__find(traceid_list, trace_chan_id);
+ if (!inode)
+ return -EINVAL;
+
+ metadata = inode->priv;
+
+ if (metadata[CS_ETM_MAGIC] == __perf_cs_etmv3_magic) {
+ val = metadata[CS_ETM_ETMCR];
+ /* CONTEXTIDR is traced */
+ if (val & BIT(ETM_OPT_CTXTID))
+ *pid_fmt = BIT(ETM_OPT_CTXTID);
+ } else {
+ val = metadata[CS_ETMV4_TRCCONFIGR];
+ /* CONTEXTIDR_EL2 is traced */
+ if (val & (BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT)))
+ *pid_fmt = BIT(ETM_OPT_CTXTID2);
+ /* CONTEXTIDR_EL1 is traced */
+ else if (val & BIT(ETM4_CFG_BIT_CTXTID))
+ *pid_fmt = BIT(ETM_OPT_CTXTID);
+ }
+
+ return 0;
+}
+
void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
u8 trace_chan_id)
{
diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
index 4ad925d6d799..7cc3bba0017d 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -173,6 +173,7 @@ struct cs_etm_packet_queue {
int cs_etm__process_auxtrace_info(union perf_event *event,
struct perf_session *session);
int cs_etm__get_cpu(u8 trace_chan_id, int *cpu);
+int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt);
int cs_etm__etmq_set_tid(struct cs_etm_queue *etmq,
pid_t tid, u8 trace_chan_id);
bool cs_etm__etmq_is_timeless(struct cs_etm_queue *etmq);
--
2.25.1