1 files changed, 30 insertions, 0 deletions
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 65d0eb9a740a..ad209c88a124 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -33,6 +33,7 @@
 #include "strbuf.h"
 #include "fncache.h"
 #include "pmu-hybrid.h"
+#include "util/evsel_config.h"
 
 struct perf_pmu perf_pmu__fake;
 
@@ -1056,6 +1057,35 @@ bool evsel__is_aux_event(const struct evsel *evsel)
 	return pmu && pmu->auxtrace;
 }
 
+/*
+ * Set @config_name to @val as long as the user hasn't already set or cleared it
+ * by passing a config term on the command line.
+ *
+ * @val is the value to put into the bits specified by @config_name rather than
+ * the bit pattern. It is shifted into position by this function, so to set
+ * something to true, pass 1 for val rather than a pre shifted value.
+ */
+#define field_prep(_mask, _val) (((_val) << (ffsll(_mask) - 1)) & (_mask))
+void evsel__set_config_if_unset(struct perf_pmu *pmu, struct evsel *evsel,
+				const char *config_name, u64 val)
+{
+	u64 user_bits = 0, bits;
+	struct evsel_config_term *term = evsel__get_config_term(evsel, CFG_CHG);
+
+	if (term)
+		user_bits = term->val.cfg_chg;
+
+	bits = perf_pmu__format_bits(&pmu->format, config_name);
+
+	/* Do nothing if the user changed the value */
+	if (bits & user_bits)
+		return;
+
+	/* Otherwise replace it */
+	evsel->core.attr.config &= ~bits;
+	evsel->core.attr.config |= field_prep(bits, val);
+}
+
 struct perf_pmu *perf_pmu__find(const char *name)
 {
 	struct perf_pmu *pmu;