perf evsel: Support sparse fields in evsel__set_config_if_unset()

Sparse config fields are technically supported although currently
unused. field_prep() only works for contiguous bitfields so replace it
with pmu_format_value().

pmu_format_value() also takes a bitmap rather than a u64 so replace
'u64 bits' with format->bits.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -1323,25 +1323,28 @@ struct evsel_config_term *__evsel__get_config_term(struct evsel *evsel, enum evs
  * 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 evsel *evsel, const char *config_name,
 				u64 val)
 {
-	u64 user_bits = 0, bits;
+	u64 user_bits = 0;
 	struct evsel_config_term *term = evsel__get_config_term(evsel, CFG_CHG);
+	struct perf_pmu_format *format = pmu_find_format(&evsel->pmu->format,
+							 config_name);
+	int fbit;
+
+	if (!format)
+		return;
 
 	if (term)
 		user_bits = term->val.cfg_chg;
 
-	bits = perf_pmu__format_bits(evsel->pmu, config_name);
-
 	/* Do nothing if the user changed the value */
-	if (bits & user_bits)
-		return;
+	for_each_set_bit(fbit, format->bits, PERF_PMU_FORMAT_BITS)
+		if ((1ULL << fbit) & user_bits)
+			return;
 
 	/* Otherwise replace it */
-	evsel->core.attr.config &= ~bits;
-	evsel->core.attr.config |= field_prep(bits, val);
+	pmu_format_value(format->bits, val, &evsel->core.attr.config, /*zero=*/true);
 }
 
 void __weak arch_evsel__set_sample_weight(struct evsel *evsel)

tools/perf/util/pmu.c

@@ -118,31 +118,6 @@ struct perf_pmu_alias {
 	bool info_loaded;
 };
 
-/**
- * struct perf_pmu_format - Values from a format file read from
- * <sysfs>/devices/cpu/format/ held in struct perf_pmu.
- *
- * For example, the contents of <sysfs>/devices/cpu/format/event may be
- * "config:0-7" and will be represented here as name="event",
- * value=PERF_PMU_FORMAT_VALUE_CONFIG and bits 0 to 7 will be set.
- */
-struct perf_pmu_format {
-	/** @list: Element on list within struct perf_pmu. */
-	struct list_head list;
-	/** @bits: Which config bits are set by this format value. */
-	DECLARE_BITMAP(bits, PERF_PMU_FORMAT_BITS);
-	/** @name: The modifier/file name. */
-	char *name;
-	/**
-	 * @value : Which config value the format relates to. Supported values
-	 * are from PERF_PMU_FORMAT_VALUE_CONFIG to
-	 * PERF_PMU_FORMAT_VALUE_CONFIG_END.
-	 */
-	u16 value;
-	/** @loaded: Has the contents been loaded/parsed. */
-	bool loaded;
-};
-
 static int pmu_aliases_parse(struct perf_pmu *pmu);
 
 static struct perf_pmu_format *perf_pmu__new_format(struct list_head *list, char *name)
@@ -1362,8 +1337,8 @@ void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu)
 	}
 }
 
-static struct perf_pmu_format *
-pmu_find_format(const struct list_head *formats, const char *name)
+struct perf_pmu_format *pmu_find_format(const struct list_head *formats,
+					const char *name)
 {
 	struct perf_pmu_format *format;
 
@@ -1404,8 +1379,7 @@ int perf_pmu__format_type(struct perf_pmu *pmu, const char *name)
  * Sets value based on the format definition (format parameter)
  * and unformatted value (value parameter).
  */
-static void pmu_format_value(unsigned long *format, __u64 value, __u64 *v,
-			     bool zero)
+void pmu_format_value(unsigned long *format, __u64 value, __u64 *v, bool zero)
 {
 	unsigned long fbit, vbit;
 

tools/perf/util/pmu.h

@@ -233,6 +233,31 @@ struct pmu_event_info {
 	bool deprecated;
 };
 
+/**
+ * struct perf_pmu_format - Values from a format file read from
+ * <sysfs>/devices/cpu/format/ held in struct perf_pmu.
+ *
+ * For example, the contents of <sysfs>/devices/cpu/format/event may be
+ * "config:0-7" and will be represented here as name="event",
+ * value=PERF_PMU_FORMAT_VALUE_CONFIG and bits 0 to 7 will be set.
+ */
+struct perf_pmu_format {
+	/** @list: Element on list within struct perf_pmu. */
+	struct list_head list;
+	/** @bits: Which config bits are set by this format value. */
+	DECLARE_BITMAP(bits, PERF_PMU_FORMAT_BITS);
+	/** @name: The modifier/file name. */
+	char *name;
+	/**
+	 * @value : Which config value the format relates to. Supported values
+	 * are from PERF_PMU_FORMAT_VALUE_CONFIG to
+	 * PERF_PMU_FORMAT_VALUE_CONFIG_END.
+	 */
+	u16 value;
+	/** @loaded: Has the contents been loaded/parsed. */
+	bool loaded;
+};
+
 typedef int (*pmu_event_callback)(void *state, struct pmu_event_info *info);
 typedef int (*pmu_format_callback)(void *state, const char *name, int config,
 				   const unsigned long *bits);
@@ -254,6 +279,9 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct parse_events_terms *head_
 			  u64 *alternate_hw_config, struct parse_events_error *err);
 int perf_pmu__find_event(struct perf_pmu *pmu, const char *event, void *state, pmu_event_callback cb);
 
+void pmu_format_value(unsigned long *format, __u64 value, __u64 *v, bool zero);
+struct perf_pmu_format *pmu_find_format(const struct list_head *formats,
+					const char *name);
 void perf_pmu_format__set_value(void *format, int config, unsigned long *bits);
 bool perf_pmu__has_format(const struct perf_pmu *pmu, const char *name);
 int perf_pmu__for_each_format(struct perf_pmu *pmu, void *state, pmu_format_callback cb);