perf cs-etm: Use struct perf_cpu as much as possible

The perf_cpu struct makes some iterators simpler and avoids some
mistakes with interchanging CPU IDs with indexes etc. At the moment in
this file the conversion to an integer is done somewhere in the middle
of the call tree. Change it to delay the conversion to an int until the
leaf functions.

Some of the usage patterns are duplicated, so instead of changing them
all, make cs_etm_get_ro() more reusable and use that everywhere.
cs_etm_get_ro() didn't return an error before, but return one now so
that it can also be used where an error is needed. Continue to ignore
the error where it was already ignored.

Use cs_etm_pmu_path_exists() instead of cs_etm_get_ro() in
cs_etm_is_etmv4() because cs_etm_get_ro() prints a warning, but path
exists is sufficient for this use case.

Signed-off-by: James Clark <james.clark@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kan Liang <kan.liang@linux.intel.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>
Link: https://lore.kernel.org/r/20240501135753.508022-2-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 88 insertions, 116 deletions

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 07be32d99805..a1fa711dc41a 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -66,18 +66,19 @@ static const char * const metadata_ete_ro[] = {
 	[CS_ETE_TS_SOURCE]		= "ts_source",
 };
 
-static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
-static bool cs_etm_is_ete(struct auxtrace_record *itr, int cpu);
+static bool cs_etm_is_etmv4(struct auxtrace_record *itr, struct perf_cpu cpu);
+static bool cs_etm_is_ete(struct auxtrace_record *itr, struct perf_cpu cpu);
+static int cs_etm_get_ro(struct perf_pmu *pmu, struct perf_cpu cpu, const char *path, __u64 *val);
+static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, struct perf_cpu cpu, const char *path);
 
-static int cs_etm_validate_context_id(struct auxtrace_record *itr,
-				      struct evsel *evsel, int cpu)
+static int cs_etm_validate_context_id(struct auxtrace_record *itr, struct evsel *evsel,
+				      struct perf_cpu cpu)
 {
 	struct cs_etm_recording *ptr =
 		container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
-	char path[PATH_MAX];
 	int err;
-	u32 val;
+	__u64 val;
 	u64 contextid = evsel->core.attr.config &
 		(perf_pmu__format_bits(cs_etm_pmu, "contextid") |
 		 perf_pmu__format_bits(cs_etm_pmu, "contextid1") |
@@ -94,16 +95,9 @@ static int cs_etm_validate_context_id(struct auxtrace_record *itr,
 	}
 
 	/* Get a handle on TRCIDR2 */
-	snprintf(path, PATH_MAX, "cpu%d/%s",
-		 cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR2]);
-	err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
-
-	/* There was a problem reading the file, bailing out */
-	if (err != 1) {
-		pr_err("%s: can't read file %s\n", CORESIGHT_ETM_PMU_NAME,
-		       path);
+	err = cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR2], &val);
+	if (err)
 		return err;
-	}
 
 	if (contextid &
 	    perf_pmu__format_bits(cs_etm_pmu, "contextid1")) {
@@ -140,15 +134,14 @@ static int cs_etm_validate_context_id(struct auxtrace_record *itr,
 	return 0;
 }
 
-static int cs_etm_validate_timestamp(struct auxtrace_record *itr,
-				     struct evsel *evsel, int cpu)
+static int cs_etm_validate_timestamp(struct auxtrace_record *itr, struct evsel *evsel,
+				     struct perf_cpu cpu)
 {
 	struct cs_etm_recording *ptr =
 		container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
-	char path[PATH_MAX];
 	int err;
-	u32 val;
+	__u64 val;
 
 	if (!(evsel->core.attr.config &
 	      perf_pmu__format_bits(cs_etm_pmu, "timestamp")))
@@ -161,16 +154,9 @@ static int cs_etm_validate_timestamp(struct auxtrace_record *itr,
 	}
 
 	/* Get a handle on TRCIRD0 */
-	snprintf(path, PATH_MAX, "cpu%d/%s",
-		 cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
-	err = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
-
-	/* There was a problem reading the file, bailing out */
-	if (err != 1) {
-		pr_err("%s: can't read file %s\n",
-		       CORESIGHT_ETM_PMU_NAME, path);
+	err = cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0], &val);
+	if (err)
 		return err;
-	}
 
 	/*
 	 * TRCIDR0.TSSIZE, bit [28-24], indicates whether global timestamping
@@ -218,11 +204,11 @@ static int cs_etm_validate_config(struct auxtrace_record *itr,
 	}
 
 	perf_cpu_map__for_each_cpu_skip_any(cpu, idx, intersect_cpus) {
-		err = cs_etm_validate_context_id(itr, evsel, cpu.cpu);
+		err = cs_etm_validate_context_id(itr, evsel, cpu);
 		if (err)
 			break;
 
-		err = cs_etm_validate_timestamp(itr, evsel, cpu.cpu);
+		err = cs_etm_validate_timestamp(itr, evsel, cpu);
 		if (err)
 			break;
 	}
@@ -549,9 +535,9 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
 		intersect_cpus = perf_cpu_map__new_online_cpus();
 	}
 	perf_cpu_map__for_each_cpu_skip_any(cpu, idx, intersect_cpus) {
-		if (cs_etm_is_ete(itr, cpu.cpu))
+		if (cs_etm_is_ete(itr, cpu))
 			ete++;
-		else if (cs_etm_is_etmv4(itr, cpu.cpu))
+		else if (cs_etm_is_etmv4(itr, cpu))
 			etmv4++;
 		else
 			etmv3++;
@@ -564,66 +550,59 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
 	       (etmv3 * CS_ETMV3_PRIV_SIZE));
 }
 
-static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu)
+static bool cs_etm_is_etmv4(struct auxtrace_record *itr, struct perf_cpu cpu)
 {
-	bool ret = false;
-	char path[PATH_MAX];
-	int scan;
-	unsigned int val;
 	struct cs_etm_recording *ptr =
 			container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 
 	/* Take any of the RO files for ETMv4 and see if it present */
-	snprintf(path, PATH_MAX, "cpu%d/%s",
-		 cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
-	scan = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
-
-	/* The file was read successfully, we have a winner */
-	if (scan == 1)
-		ret = true;
-
-	return ret;
+	return cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
 }
 
-static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
+static int cs_etm_get_ro(struct perf_pmu *pmu, struct perf_cpu cpu, const char *path, __u64 *val)
 {
 	char pmu_path[PATH_MAX];
 	int scan;
-	unsigned int val = 0;
 
 	/* Get RO metadata from sysfs */
-	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
+	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu.cpu, path);
 
-	scan = perf_pmu__scan_file(pmu, pmu_path, "%x", &val);
-	if (scan != 1)
+	scan = perf_pmu__scan_file(pmu, pmu_path, "%llx", val);
+	if (scan != 1) {
 		pr_err("%s: error reading: %s\n", __func__, pmu_path);
+		return -EINVAL;
+	}
 
-	return val;
+	return 0;
 }
 
-static int cs_etm_get_ro_signed(struct perf_pmu *pmu, int cpu, const char *path)
+static int cs_etm_get_ro_signed(struct perf_pmu *pmu, struct perf_cpu cpu, const char *path,
+				__u64 *out_val)
 {
 	char pmu_path[PATH_MAX];
 	int scan;
 	int val = 0;
 
 	/* Get RO metadata from sysfs */
-	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
+	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu.cpu, path);
 
 	scan = perf_pmu__scan_file(pmu, pmu_path, "%d", &val);
-	if (scan != 1)
+	if (scan != 1) {
 		pr_err("%s: error reading: %s\n", __func__, pmu_path);
+		return -EINVAL;
+	}
 
-	return val;
+	*out_val = (__u64) val;
+	return 0;
 }
 
-static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, int cpu, const char *path)
+static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, struct perf_cpu cpu, const char *path)
 {
 	char pmu_path[PATH_MAX];
 
 	/* Get RO metadata from sysfs */
-	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
+	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu.cpu, path);
 
 	return perf_pmu__file_exists(pmu, pmu_path);
 }
@@ -636,16 +615,16 @@ static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, int cpu, const char *pa
 #define TRCDEVARCH_ARCHVER_MASK  GENMASK(15, 12)
 #define TRCDEVARCH_ARCHVER(x)    (((x) & TRCDEVARCH_ARCHVER_MASK) >> TRCDEVARCH_ARCHVER_SHIFT)
 
-static bool cs_etm_is_ete(struct auxtrace_record *itr, int cpu)
+static bool cs_etm_is_ete(struct auxtrace_record *itr, struct perf_cpu cpu)
 {
 	struct cs_etm_recording *ptr = container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
-	int trcdevarch;
+	__u64 trcdevarch;
 
 	if (!cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCDEVARCH]))
 		return false;
 
-	trcdevarch = cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCDEVARCH]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCDEVARCH], &trcdevarch);
 	/*
 	 * ETE if ARCHVER is 5 (ARCHVER is 4 for ETM) and ARCHPART is 0xA13.
 	 * See ETM_DEVARCH_ETE_ARCH in coresight-etm4x.h
@@ -653,7 +632,12 @@ static bool cs_etm_is_ete(struct auxtrace_record *itr, int cpu)
 	return TRCDEVARCH_ARCHVER(trcdevarch) == 5 && TRCDEVARCH_ARCHPART(trcdevarch) == 0xA13;
 }
 
-static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr, int cpu)
+static __u64 cs_etm_get_legacy_trace_id(struct perf_cpu cpu)
+{
+	return CORESIGHT_LEGACY_CPU_TRACE_ID(cpu.cpu);
+}
+
+static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr, struct perf_cpu cpu)
 {
 	struct cs_etm_recording *ptr = container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
@@ -661,33 +645,32 @@ static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr,
 	/* Get trace configuration register */
 	data[CS_ETMV4_TRCCONFIGR] = cs_etmv4_get_config(itr);
 	/* traceID set to legacy version, in case new perf running on older system */
-	data[CS_ETMV4_TRCTRACEIDR] =
-		CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
+	data[CS_ETMV4_TRCTRACEIDR] = cs_etm_get_legacy_trace_id(cpu) |
+				     CORESIGHT_TRACE_ID_UNUSED_FLAG;
 
 	/* Get read-only information from sysFS */
-	data[CS_ETMV4_TRCIDR0] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					       metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
-	data[CS_ETMV4_TRCIDR1] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					       metadata_etmv4_ro[CS_ETMV4_TRCIDR1]);
-	data[CS_ETMV4_TRCIDR2] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					       metadata_etmv4_ro[CS_ETMV4_TRCIDR2]);
-	data[CS_ETMV4_TRCIDR8] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					       metadata_etmv4_ro[CS_ETMV4_TRCIDR8]);
-	data[CS_ETMV4_TRCAUTHSTATUS] = cs_etm_get_ro(cs_etm_pmu, cpu,
-						     metadata_etmv4_ro[CS_ETMV4_TRCAUTHSTATUS]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0],
+		      &data[CS_ETMV4_TRCIDR0]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR1],
+		      &data[CS_ETMV4_TRCIDR1]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR2],
+		      &data[CS_ETMV4_TRCIDR2]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR8],
+		      &data[CS_ETMV4_TRCIDR8]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TRCAUTHSTATUS],
+		      &data[CS_ETMV4_TRCAUTHSTATUS]);
 
 	/* Kernels older than 5.19 may not expose ts_source */
-	if (cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TS_SOURCE]))
-		data[CS_ETMV4_TS_SOURCE] = (__u64) cs_etm_get_ro_signed(cs_etm_pmu, cpu,
-				metadata_etmv4_ro[CS_ETMV4_TS_SOURCE]);
-	else {
+	if (!cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TS_SOURCE]) ||
+	    cs_etm_get_ro_signed(cs_etm_pmu, cpu, metadata_etmv4_ro[CS_ETMV4_TS_SOURCE],
+				 &data[CS_ETMV4_TS_SOURCE])) {
 		pr_debug3("[%03d] pmu file 'ts_source' not found. Fallback to safe value (-1)\n",
-			  cpu);
+			  cpu.cpu);
 		data[CS_ETMV4_TS_SOURCE] = (__u64) -1;
 	}
 }
 
-static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, int cpu)
+static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, struct perf_cpu cpu)
 {
 	struct cs_etm_recording *ptr = container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
@@ -695,36 +678,30 @@ static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, in
 	/* Get trace configuration register */
 	data[CS_ETE_TRCCONFIGR] = cs_etmv4_get_config(itr);
 	/* traceID set to legacy version, in case new perf running on older system */
-	data[CS_ETE_TRCTRACEIDR] =
-		CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
+	data[CS_ETE_TRCTRACEIDR] = cs_etm_get_legacy_trace_id(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
 
 	/* Get read-only information from sysFS */
-	data[CS_ETE_TRCIDR0] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					     metadata_ete_ro[CS_ETE_TRCIDR0]);
-	data[CS_ETE_TRCIDR1] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					     metadata_ete_ro[CS_ETE_TRCIDR1]);
-	data[CS_ETE_TRCIDR2] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					     metadata_ete_ro[CS_ETE_TRCIDR2]);
-	data[CS_ETE_TRCIDR8] = cs_etm_get_ro(cs_etm_pmu, cpu,
-					     metadata_ete_ro[CS_ETE_TRCIDR8]);
-	data[CS_ETE_TRCAUTHSTATUS] = cs_etm_get_ro(cs_etm_pmu, cpu,
-						   metadata_ete_ro[CS_ETE_TRCAUTHSTATUS]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCIDR0], &data[CS_ETE_TRCIDR0]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCIDR1], &data[CS_ETE_TRCIDR1]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCIDR2], &data[CS_ETE_TRCIDR2]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCIDR8], &data[CS_ETE_TRCIDR8]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCAUTHSTATUS],
+		      &data[CS_ETE_TRCAUTHSTATUS]);
 	/* ETE uses the same registers as ETMv4 plus TRCDEVARCH */
-	data[CS_ETE_TRCDEVARCH] = cs_etm_get_ro(cs_etm_pmu, cpu,
-						metadata_ete_ro[CS_ETE_TRCDEVARCH]);
+	cs_etm_get_ro(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TRCDEVARCH],
+		      &data[CS_ETE_TRCDEVARCH]);
 
 	/* Kernels older than 5.19 may not expose ts_source */
-	if (cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TS_SOURCE]))
-		data[CS_ETE_TS_SOURCE] = (__u64) cs_etm_get_ro_signed(cs_etm_pmu, cpu,
-				metadata_ete_ro[CS_ETE_TS_SOURCE]);
-	else {
+	if (!cs_etm_pmu_path_exists(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TS_SOURCE]) ||
+	    cs_etm_get_ro_signed(cs_etm_pmu, cpu, metadata_ete_ro[CS_ETE_TS_SOURCE],
+				 &data[CS_ETE_TS_SOURCE])) {
 		pr_debug3("[%03d] pmu file 'ts_source' not found. Fallback to safe value (-1)\n",
-			  cpu);
+			  cpu.cpu);
 		data[CS_ETE_TS_SOURCE] = (__u64) -1;
 	}
 }
 
-static void cs_etm_get_metadata(int cpu, u32 *offset,
+static void cs_etm_get_metadata(struct perf_cpu cpu, u32 *offset,
 				struct auxtrace_record *itr,
 				struct perf_record_auxtrace_info *info)
 {
@@ -754,15 +731,13 @@ static void cs_etm_get_metadata(int cpu, u32 *offset,
 		/* Get configuration register */
 		info->priv[*offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
 		/* traceID set to legacy value in case new perf running on old system */
-		info->priv[*offset + CS_ETM_ETMTRACEIDR] =
-			CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
+		info->priv[*offset + CS_ETM_ETMTRACEIDR] = cs_etm_get_legacy_trace_id(cpu) |
+							   CORESIGHT_TRACE_ID_UNUSED_FLAG;
 		/* Get read-only information from sysFS */
-		info->priv[*offset + CS_ETM_ETMCCER] =
-			cs_etm_get_ro(cs_etm_pmu, cpu,
-				      metadata_etmv3_ro[CS_ETM_ETMCCER]);
-		info->priv[*offset + CS_ETM_ETMIDR] =
-			cs_etm_get_ro(cs_etm_pmu, cpu,
-				      metadata_etmv3_ro[CS_ETM_ETMIDR]);
+		cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv3_ro[CS_ETM_ETMCCER],
+			      &info->priv[*offset + CS_ETM_ETMCCER]);
+		cs_etm_get_ro(cs_etm_pmu, cpu, metadata_etmv3_ro[CS_ETM_ETMIDR],
+			      &info->priv[*offset + CS_ETM_ETMIDR]);
 
 		/* How much space was used */
 		increment = CS_ETM_PRIV_MAX;
@@ -771,7 +746,7 @@ static void cs_etm_get_metadata(int cpu, u32 *offset,
 
 	/* Build generic header portion */
 	info->priv[*offset + CS_ETM_MAGIC] = magic;
-	info->priv[*offset + CS_ETM_CPU] = cpu;
+	info->priv[*offset + CS_ETM_CPU] = cpu.cpu;
 	info->priv[*offset + CS_ETM_NR_TRC_PARAMS] = nr_trc_params;
 	/* Where the next CPU entry should start from */
 	*offset += increment;
@@ -791,6 +766,7 @@ static int cs_etm_info_fill(struct auxtrace_record *itr,
 	struct cs_etm_recording *ptr =
 			container_of(itr, struct cs_etm_recording, itr);
 	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
+	struct perf_cpu cpu;
 
 	if (priv_size != cs_etm_info_priv_size(itr, session->evlist))
 		return -EINVAL;
@@ -803,8 +779,6 @@ static int cs_etm_info_fill(struct auxtrace_record *itr,
 		cpu_map = online_cpus;
 	} else {
 		/* Make sure all specified CPUs are online */
-		struct perf_cpu cpu;
-
 		perf_cpu_map__for_each_cpu(cpu, i, event_cpus) {
 			if (!perf_cpu_map__has(online_cpus, cpu))
 				return -EINVAL;
@@ -826,11 +800,9 @@ static int cs_etm_info_fill(struct auxtrace_record *itr,
 
 	offset = CS_ETM_SNAPSHOT + 1;
 
-	for (i = 0; i < cpu__max_cpu().cpu && offset < priv_size; i++) {
-		struct perf_cpu cpu = { .cpu = i, };
-
-		if (perf_cpu_map__has(cpu_map, cpu))
-			cs_etm_get_metadata(i, &offset, itr, info);
+	perf_cpu_map__for_each_cpu(cpu, i, cpu_map) {
+		assert(offset < priv_size);
+		cs_etm_get_metadata(cpu, &offset, itr, info);
 	}
 
 	perf_cpu_map__put(online_cpus);