1 files changed, 133 insertions, 0 deletions
diff --git a/tools/verification/rv/src/trace.c b/tools/verification/rv/src/trace.c
new file mode 100644
index 000000000000..2c7deed47f8d
--- /dev/null
+++ b/tools/verification/rv/src/trace.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace helpers.
+ *
+ * Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
+ */
+
+#include <sys/sendfile.h>
+#include <tracefs.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <rv.h>
+#include <trace.h>
+#include <utils.h>
+
+/*
+ * create_instance - create a trace instance with *instance_name
+ */
+static struct tracefs_instance *create_instance(char *instance_name)
+{
+	return tracefs_instance_create(instance_name);
+}
+
+/*
+ * destroy_instance - remove a trace instance and free the data
+ */
+static void destroy_instance(struct tracefs_instance *inst)
+{
+	tracefs_instance_destroy(inst);
+	tracefs_instance_free(inst);
+}
+
+/**
+ * collect_registered_events - call the existing callback function for the event
+ *
+ * If an event has a registered callback function, call it.
+ * Otherwise, ignore the event.
+ *
+ * Returns 0 if the event was collected, 1 if the tool should stop collecting trace.
+ */
+int
+collect_registered_events(struct tep_event *event, struct tep_record *record,
+			  int cpu, void *context)
+{
+	struct trace_instance *trace = context;
+	struct trace_seq *s = trace->seq;
+
+	if (should_stop())
+		return 1;
+
+	if (!event->handler)
+		return 0;
+
+	event->handler(s, record, event, context);
+
+	return 0;
+}
+
+/**
+ * trace_instance_destroy - destroy and free a rv trace instance
+ */
+void trace_instance_destroy(struct trace_instance *trace)
+{
+	if (trace->inst) {
+		destroy_instance(trace->inst);
+		trace->inst = NULL;
+	}
+
+	if (trace->seq) {
+		free(trace->seq);
+		trace->seq = NULL;
+	}
+
+	if (trace->tep) {
+		tep_free(trace->tep);
+		trace->tep = NULL;
+	}
+}
+
+/**
+ * trace_instance_init - create an trace instance
+ *
+ * It is more than the tracefs instance, as it contains other
+ * things required for the tracing, such as the local events and
+ * a seq file.
+ *
+ * Note that the trace instance is returned disabled. This allows
+ * the tool to apply some other configs, like setting priority
+ * to the kernel threads, before starting generating trace entries.
+ *
+ * Returns 0 on success, non-zero otherwise.
+ */
+int trace_instance_init(struct trace_instance *trace, char *name)
+{
+	trace->seq = calloc(1, sizeof(*trace->seq));
+	if (!trace->seq)
+		goto out_err;
+
+	trace_seq_init(trace->seq);
+
+	trace->inst = create_instance(name);
+	if (!trace->inst)
+		goto out_err;
+
+	trace->tep = tracefs_local_events(NULL);
+	if (!trace->tep)
+		goto out_err;
+
+	/*
+	 * Let the main enable the record after setting some other
+	 * things such as the priority of the tracer's threads.
+	 */
+	tracefs_trace_off(trace->inst);
+
+	return 0;
+
+out_err:
+	trace_instance_destroy(trace);
+	return 1;
+}
+
+/**
+ * trace_instance_start - start tracing a given rv instance
+ *
+ * Returns 0 on success, -1 otherwise.
+ */
+int trace_instance_start(struct trace_instance *trace)
+{
+	return tracefs_trace_on(trace->inst);
+}