[PATCH v2 05/12] perf evsel: Add a helper to get the value of a config field

[James Clark <james.clark@linaro.org>]

This will be used by aux PMUs to read an already written value for
configuring their events and for also testing.

Its helper pmu_format_unpack() does the opposite of the existing
pmu_format_value() so rename that one to pmu_format_pack() so it's clear
how they are related.

Signed-off-by: James Clark <james.clark@linaro.org>
---
 tools/perf/util/evsel.h |  2 ++
 tools/perf/util/pmu.c   | 77 ++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index a08130ff2e47..092904a61ec7 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -575,6 +575,8 @@ void evsel__uniquify_counter(struct evsel *counter);
 	((((src) >> (pos)) & ((1ull << (size)) - 1)) << (63 - ((pos) + (size) - 1)))
 
 u64 evsel__bitfield_swap_branch_flags(u64 value);
+int evsel__get_config_val(struct perf_pmu *pmu, struct evsel *evsel,
+			  const char *config_name, u64 *val);
 void evsel__set_config_if_unset(struct perf_pmu *pmu, struct evsel *evsel,
 				const char *config_name, u64 val);
 
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 514cba91f5d9..ef7358ad1fb9 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -144,8 +144,8 @@ struct perf_pmu_format {
 };
 
 static int pmu_aliases_parse(struct perf_pmu *pmu);
-static void pmu_format_value(unsigned long *format, __u64 value, __u64 *v,
-			     bool zero);
+static void pmu_format_pack(unsigned long *format, __u64 value, __u64 *v,
+			    bool zero);
 static struct perf_pmu_format *pmu_find_format(const struct list_head *formats,
 					       const char *name);
 
@@ -1377,6 +1377,61 @@ bool evsel__is_aux_event(const struct evsel *evsel)
 	return pmu && pmu->auxtrace;
 }
 
+/*
+ * Unpacks a raw config[n] value using the sparse bitfield that defines a
+ * format attr. For example "config1:1,6-7,44" defines a 4 bit value across non
+ * contiguous bits and this function returns those 4 bits as a value.
+ */
+static u64 pmu_format_unpack(u64 format, u64 config_val)
+{
+	int val_bit = 0;
+	u64 res = 0;
+	int fmt_bit;
+
+	for_each_set_bit(fmt_bit, &format, PERF_PMU_FORMAT_BITS) {
+		if (test_bit(fmt_bit, &config_val))
+			res |= BIT_ULL(val_bit);
+
+		val_bit++;
+	}
+	return res;
+}
+
+int evsel__get_config_val(struct perf_pmu *pmu, struct evsel *evsel,
+			  const char *config_name, u64 *val)
+{
+	struct perf_pmu_format *format = pmu_find_format(&pmu->format, config_name);
+	u64 bits = perf_pmu__format_bits(pmu, config_name);
+
+	if (!format || !bits) {
+		pr_err("Unknown/empty format name: %s\n", config_name);
+		*val = 0;
+		return -EINVAL;
+	}
+
+	switch (format->value) {
+	case PERF_PMU_FORMAT_VALUE_CONFIG:
+		*val = pmu_format_unpack(bits, evsel->core.attr.config);
+		return 0;
+	case PERF_PMU_FORMAT_VALUE_CONFIG1:
+		*val = pmu_format_unpack(bits, evsel->core.attr.config1);
+		return 0;
+	case PERF_PMU_FORMAT_VALUE_CONFIG2:
+		*val = pmu_format_unpack(bits, evsel->core.attr.config2);
+		return 0;
+	case PERF_PMU_FORMAT_VALUE_CONFIG3:
+		*val = pmu_format_unpack(bits, evsel->core.attr.config3);
+		return 0;
+	case PERF_PMU_FORMAT_VALUE_CONFIG4:
+		*val = pmu_format_unpack(bits, evsel->core.attr.config4);
+		return 0;
+	default:
+		pr_err("Unknown format value: %d\n", format->value);
+		*val = 0;
+		return -EINVAL;
+	}
+}
+
 /*
  * 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.
@@ -1432,7 +1487,7 @@ void evsel__set_config_if_unset(struct perf_pmu *pmu, struct evsel *evsel,
 		return;
 
 	/* Otherwise replace it */
-	pmu_format_value(&bits, val, vp, /*zero=*/true);
+	pmu_format_pack(&bits, val, vp, /*zero=*/true);
 }
 
 static struct perf_pmu_format *
@@ -1477,8 +1532,8 @@ 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)
+static void pmu_format_pack(unsigned long *format, __u64 value, __u64 *v,
+			    bool zero)
 {
 	unsigned long fbit, vbit;
 
@@ -1595,23 +1650,23 @@ static int pmu_config_term(const struct perf_pmu *pmu,
 		switch (term->type_term) {
 		case PARSE_EVENTS__TERM_TYPE_CONFIG:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
-			pmu_format_value(bits, term->val.num, &attr->config, zero);
+			pmu_format_pack(bits, term->val.num, &attr->config, zero);
 			break;
 		case PARSE_EVENTS__TERM_TYPE_CONFIG1:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
-			pmu_format_value(bits, term->val.num, &attr->config1, zero);
+			pmu_format_pack(bits, term->val.num, &attr->config1, zero);
 			break;
 		case PARSE_EVENTS__TERM_TYPE_CONFIG2:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
-			pmu_format_value(bits, term->val.num, &attr->config2, zero);
+			pmu_format_pack(bits, term->val.num, &attr->config2, zero);
 			break;
 		case PARSE_EVENTS__TERM_TYPE_CONFIG3:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
-			pmu_format_value(bits, term->val.num, &attr->config3, zero);
+			pmu_format_pack(bits, term->val.num, &attr->config3, zero);
 			break;
 		case PARSE_EVENTS__TERM_TYPE_CONFIG4:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
-			pmu_format_value(bits, term->val.num, &attr->config4, zero);
+			pmu_format_pack(bits, term->val.num, &attr->config4, zero);
 			break;
 		case PARSE_EVENTS__TERM_TYPE_LEGACY_HARDWARE_CONFIG:
 			assert(term->type_val == PARSE_EVENTS__TERM_TYPE_NUM);
@@ -1749,7 +1804,7 @@ static int pmu_config_term(const struct perf_pmu *pmu,
 		 */
 	}
 
-	pmu_format_value(format->bits, val, vp, zero);
+	pmu_format_pack(format->bits, val, vp, zero);
 	return 0;
 }
 

-- 
2.34.1