Re: [PATCH 2/2] perf tools: Fix term parsing for raw syntax

From: Ian Rogers
Date: Sat Jul 25 2020 - 12:59:34 EST

On Sat, Jul 25, 2020 at 5:20 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Jin Yao reported issue with possible conflict between raw
> events and term values in pmu event syntax.
>
> Currently following syntax is resolved as raw event with
> 0xead value:
> uncore_imc_free_running/read/
>
> instead of using 'read' term from uncore_imc_free_running pmu,
> because 'read' is correct raw event syntax with 0xead value.
>
> To solve this issue we do following:
> - check existing terms during rXXXX syntax processing
> and make them priority in case of conflict
> - allow pmu/r0x1234/ syntax to be able to specify conflicting
> raw event (implemented in previous patch)
>
> Also adding automated tests for this and perf_pmu__parse_cleanup
> call to parse_events_terms, so the test gets properly cleaned up.
>
> Reported-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/perf/tests/parse-events.c | 37 ++++++++++++++++++++++++++++++++-
> tools/perf/util/parse-events.c | 23 ++++++++++++++++++++
> tools/perf/util/parse-events.h | 2 ++
> tools/perf/util/parse-events.l | 19 ++++++++++-------
> 4 files changed, 72 insertions(+), 9 deletions(-)
>
> diff --git a/tools/perf/tests/parse-events.c b/tools/perf/tests/parse-events.c
> index 5aaddcb0058a..7f9f87a470c3 100644
> --- a/tools/perf/tests/parse-events.c
> +++ b/tools/perf/tests/parse-events.c
> @@ -631,6 +631,34 @@ static int test__checkterms_simple(struct list_head *terms)
> TEST_ASSERT_VAL("wrong val", term->val.num == 1);
> TEST_ASSERT_VAL("wrong config", !strcmp(term->config, "umask"));
>
> + /*
> + * read
> + *
> + * The perf_pmu__test_parse_init injects 'read' term into
> + * perf_pmu_events_list, so 'read' is evaluated as read term
> + * and not as raw event with 'ead' hex value.
> + */
> + term = list_entry(term->list.next, struct parse_events_term, list);
> + TEST_ASSERT_VAL("wrong type term",
> + term->type_term == PARSE_EVENTS__TERM_TYPE_USER);
> + TEST_ASSERT_VAL("wrong type val",
> + term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
> + TEST_ASSERT_VAL("wrong val", term->val.num == 1);
> + TEST_ASSERT_VAL("wrong config", !strcmp(term->config, "read"));
> +
> + /*
> + * r0xead
> + *
> + * To be still able to pass 'ead' value with 'r' syntax,
> + * we added support to parse 'r0xHEX' event.
> + */
> + term = list_entry(term->list.next, struct parse_events_term, list);
> + TEST_ASSERT_VAL("wrong type term",
> + term->type_term == PARSE_EVENTS__TERM_TYPE_CONFIG);
> + TEST_ASSERT_VAL("wrong type val",
> + term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
> + TEST_ASSERT_VAL("wrong val", term->val.num == 0xead);
> + TEST_ASSERT_VAL("wrong config", !term->config);
> return 0;
> }
>
> @@ -1781,7 +1809,7 @@ struct terms_test {
>
> static struct terms_test test__terms[] = {
> [0] = {
> - .str = "config=10,config1,config2=3,umask=1",
> + .str = "config=10,config1,config2=3,umask=1,read,r0xead",
> .check = test__checkterms_simple,
> },
> };
> @@ -1841,6 +1869,13 @@ static int test_term(struct terms_test *t)
>
> INIT_LIST_HEAD(&terms);
>
> + /*
> + * The perf_pmu__test_parse_init prepares perf_pmu_events_list
> + * which gets freed in parse_events_terms.
> + */
> + if (perf_pmu__test_parse_init())
> + return -1;
> +
> ret = parse_events_terms(&terms, t->str);
> if (ret) {
> pr_debug("failed to parse terms '%s', err %d\n",
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index e88e4c7a2a9a..254f02a7fb0d 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -2019,6 +2019,27 @@ static void perf_pmu__parse_init(void)
> perf_pmu__parse_cleanup();
> }
>
> +int perf_pmu__test_parse_init(void)
> +{
> + struct perf_pmu_event_symbol *list;
> +
> + list = malloc(sizeof(*list) * 1);
> + if (!list)
> + return -ENOMEM;
> +
> + list->type = PMU_EVENT_SYMBOL;
> + list->symbol = strdup("read");
> +
> + if (!list->symbol) {
> + free(list);
> + return -ENOMEM;
> + }
> +
> + perf_pmu_events_list = list;
> + perf_pmu_events_list_num = 1;
> + return 0;
> +}

nit: It's easy to see in the test code why this is necessary, could
the function be moved there? If not perhaps add a function comment?
The test in the function name is quite load bearing.

> +
> enum perf_pmu_event_symbol_type
> perf_pmu__parse_check(const char *name)
> {
> @@ -2080,6 +2101,8 @@ int parse_events_terms(struct list_head *terms, const char *str)
> int ret;
>
> ret = parse_events__scanner(str, &parse_state);
> + perf_pmu__parse_cleanup();
> +
> if (!ret) {
> list_splice(parse_state.terms, terms);
> zfree(&parse_state.terms);
> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> index f0010095fc8c..00cde7d2e30c 100644
> --- a/tools/perf/util/parse-events.h
> +++ b/tools/perf/util/parse-events.h
> @@ -261,4 +261,6 @@ static inline bool is_sdt_event(char *str __maybe_unused)
> }
> #endif /* HAVE_LIBELF_SUPPORT */
>
> +int perf_pmu__test_parse_init(void);
> +
> #endif /* __PERF_PARSE_EVENTS_H */
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> index 44c85fea5d00..3ca5fd2829ca 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -41,14 +41,6 @@ static int value(yyscan_t scanner, int base)
> return __value(yylval, text, base, PE_VALUE);
> }
>
> -static int raw(yyscan_t scanner)
> -{
> - YYSTYPE *yylval = parse_events_get_lval(scanner);
> - char *text = parse_events_get_text(scanner);
> -
> - return __value(yylval, text + 1, 16, PE_RAW);
> -}
> -
> static int str(yyscan_t scanner, int token)
> {
> YYSTYPE *yylval = parse_events_get_lval(scanner);
> @@ -72,6 +64,17 @@ static int str(yyscan_t scanner, int token)
> return token;
> }
>
> +static int raw(yyscan_t scanner)
> +{
> + YYSTYPE *yylval = parse_events_get_lval(scanner);
> + char *text = parse_events_get_text(scanner);
> +
> + if (perf_pmu__parse_check(text) == PMU_EVENT_SYMBOL)
> + return str(scanner, PE_NAME);
> +
> + return __value(yylval, text + 1, 16, PE_RAW);
> +}
> +
> static bool isbpf_suffix(char *text)
> {
> int len = strlen(text);
> --
> 2.25.4
>