perf tools: Add fake pmu support

Add a way to create a pmu event without the actual PMU being in place.

This way we can test metrics defined for any processor.

The interface is to define fake_pmu in struct parse_events_state data.
It will be used only in tests via special interface function added in
following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200602214741.1218986-2-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/parse-events.c

@@ -1450,7 +1450,7 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 		fprintf(stderr, "' that may result in non-fatal errors\n");
 	}
 
-	pmu = perf_pmu__find(name);
+	pmu = parse_state->fake_pmu ?: perf_pmu__find(name);
 	if (!pmu) {
 		char *err_str;
 
@@ -1483,7 +1483,7 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 		}
 	}
 
-	if (perf_pmu__check_alias(pmu, head_config, &info))
+	if (!parse_state->fake_pmu && perf_pmu__check_alias(pmu, head_config, &info))
 		return -EINVAL;
 
 	if (verbose > 1) {
@@ -1516,7 +1516,7 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
 	if (pmu->default_config && get_config_chgs(pmu, head_config, &config_terms))
 		return -ENOMEM;
 
-	if (perf_pmu__config(pmu, &attr, head_config, parse_state->error)) {
+	if (!parse_state->fake_pmu && perf_pmu__config(pmu, &attr, head_config, parse_state->error)) {
 		struct evsel_config_term *pos, *tmp;
 
 		list_for_each_entry_safe(pos, tmp, &config_terms, list) {

tools/perf/util/parse-events.h

@@ -130,6 +130,7 @@ struct parse_events_state {
 	struct evlist		  *evlist;
 	struct list_head	  *terms;
 	int			   stoken;
+	struct perf_pmu		  *fake_pmu;
 };
 
 void parse_events__handle_error(struct parse_events_error *err, int idx,

tools/perf/util/parse-events.l

@@ -129,12 +129,16 @@ do {								\
 	yyless(0);						\
 } while (0)
 
-static int pmu_str_check(yyscan_t scanner)
+static int pmu_str_check(yyscan_t scanner, struct parse_events_state *parse_state)
 {
 	YYSTYPE *yylval = parse_events_get_lval(scanner);
 	char *text = parse_events_get_text(scanner);
 
 	yylval->str = strdup(text);
+
+	if (parse_state->fake_pmu)
+		return PE_PMU_EVENT_FAKE;
+
 	switch (perf_pmu__parse_check(text)) {
 		case PMU_EVENT_SYMBOL_PREFIX:
 			return PE_PMU_EVENT_PRE;
@@ -376,7 +380,7 @@ r{num_raw_hex}		{ return raw(yyscanner); }
 {modifier_event}	{ return str(yyscanner, PE_MODIFIER_EVENT); }
 {bpf_object}		{ if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_OBJECT); }
 {bpf_source}		{ if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_SOURCE); }
-{name}			{ return pmu_str_check(yyscanner); }
+{name}			{ return pmu_str_check(yyscanner, _parse_state); }
 {name_tag}		{ return str(yyscanner, PE_NAME); }
 "/"			{ BEGIN(config); return '/'; }
 -			{ return '-'; }

tools/perf/util/parse-events.y

@@ -69,7 +69,7 @@ static void inc_group_count(struct list_head *list,
 %token PE_NAME_CACHE_TYPE PE_NAME_CACHE_OP_RESULT
 %token PE_PREFIX_MEM PE_PREFIX_RAW PE_PREFIX_GROUP
 %token PE_ERROR
-%token PE_PMU_EVENT_PRE PE_PMU_EVENT_SUF PE_KERNEL_PMU_EVENT
+%token PE_PMU_EVENT_PRE PE_PMU_EVENT_SUF PE_KERNEL_PMU_EVENT PE_PMU_EVENT_FAKE
 %token PE_ARRAY_ALL PE_ARRAY_RANGE
 %token PE_DRV_CFG_TERM
 %type <num> PE_VALUE
@@ -87,7 +87,7 @@ static void inc_group_count(struct list_head *list,
 %type <str> PE_MODIFIER_EVENT
 %type <str> PE_MODIFIER_BP
 %type <str> PE_EVENT_NAME
-%type <str> PE_PMU_EVENT_PRE PE_PMU_EVENT_SUF PE_KERNEL_PMU_EVENT
+%type <str> PE_PMU_EVENT_PRE PE_PMU_EVENT_SUF PE_KERNEL_PMU_EVENT PE_PMU_EVENT_FAKE
 %type <str> PE_DRV_CFG_TERM
 %destructor { free ($$); } <str>
 %type <term> event_term
@@ -356,6 +356,43 @@ PE_PMU_EVENT_PRE '-' PE_PMU_EVENT_SUF sep_dc
 		YYABORT;
 	$$ = list;
 }
+|
+PE_PMU_EVENT_FAKE sep_dc
+{
+	struct list_head *list;
+	int err;
+
+	list = alloc_list();
+	if (!list)
+		YYABORT;
+
+	err = parse_events_add_pmu(_parse_state, list, $1, NULL, false, false);
+	free($1);
+	if (err < 0) {
+		free(list);
+		YYABORT;
+	}
+	$$ = list;
+}
+|
+PE_PMU_EVENT_FAKE opt_pmu_config
+{
+	struct list_head *list;
+	int err;
+
+	list = alloc_list();
+	if (!list)
+		YYABORT;
+
+	err = parse_events_add_pmu(_parse_state, list, $1, $2, false, false);
+	free($1);
+	parse_events_terms__delete($2);
+	if (err < 0) {
+		free(list);
+		YYABORT;
+	}
+	$$ = list;
+}
 
 value_sym:
 PE_VALUE_SYM_HW