[PATCH v2 4/8] perf arm64 header: Use cpu argument in get_cpuid

Ian Rogers
2024-11-07T16:50:39Z

Use the cpu to read the MIDR file requested. If the "any" value (-1)
is passed that keep the behavior of returning the first MIDR file that
can be read.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/arch/arm64/util/header.c | 63 ++++++++++++++---------------
tools/perf/util/header.h | 1 +
2 files changed, 31 insertions(+), 33 deletions(-)

diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c
index 760c21784713..f0907daad3ae 100644
--- a/tools/perf/arch/arm64/util/header.c
+++ b/tools/perf/arch/arm64/util/header.c
@@ -14,55 +14,52 @@
#define MIDR_REVISION_MASK GENMASK(3, 0)
#define MIDR_VARIANT_MASK GENMASK(23, 20)

-static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus)
+static int _get_cpuid(char *buf, size_t sz, struct perf_cpu cpu)
{
+ char path[PATH_MAX];
+ FILE *file;
const char *sysfs = sysfs__mountpoint();
- struct perf_cpu cpu;
- int idx, ret = EINVAL;

+ assert(cpu.cpu != -1);
if (!sysfs || sz < MIDR_SIZE)
return EINVAL;

- perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
- char path[PATH_MAX];
- FILE *file;
-
- scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d" MIDR,
- sysfs, cpu.cpu);
-
- file = fopen(path, "r");
- if (!file) {
- pr_debug("fopen failed for file %s\n", path);
- continue;
- }
-
- if (!fgets(buf, MIDR_SIZE, file)) {
- fclose(file);
- continue;
- }
- fclose(file);
+ scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d" MIDR, sysfs, cpu.cpu);

- /* got midr break loop */
- ret = 0;
- break;
+ file = fopen(path, "r");
+ if (!file) {
+ pr_debug("fopen failed for file %s\n", path);
+ return EINVAL;
}

- return ret;
+ if (!fgets(buf, MIDR_SIZE, file)) {
+ pr_debug("Failed to read file %s\n", path);
+ fclose(file);
+ return EINVAL;
+ }
+ fclose(file);
+ return 0;
}

-int get_cpuid(char *buf, size_t sz, struct perf_cpu cpu __maybe_unused)
+int get_cpuid(char *buf, size_t sz, struct perf_cpu cpu)
{
- struct perf_cpu_map *cpus = perf_cpu_map__new_online_cpus();
- int ret;
+ struct perf_cpu_map *cpus;
+ int idx;
+
+ if (cpu.cpu != -1)
+ return _get_cpuid(buf, sz, cpu);

+ cpus = perf_cpu_map__new_online_cpus();
if (!cpus)
return EINVAL;

- ret = _get_cpuid(buf, sz, cpus);
-
- perf_cpu_map__put(cpus);
+ perf_cpu_map__for_each_cpu(cpu, idx, cpus) {
+ int ret = _get_cpuid(buf, sz, cpu);

- return ret;
+ if (ret == 0)
+ return 0;
+ }
+ return EINVAL;
}

char *get_cpuid_str(struct perf_pmu *pmu)
@@ -78,7 +75,7 @@ char *get_cpuid_str(struct perf_pmu *pmu)
return NULL;

/* read midr from list of cpus mapped to this pmu */
- res = _get_cpuid(buf, MIDR_SIZE, pmu->cpus);
+ res = get_cpuid(buf, MIDR_SIZE, perf_cpu_map__min(pmu->cpus));
if (res) {
pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
free(buf);
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index b77f89de12dd..3bb768455a60 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -11,6 +11,7 @@
#include <linux/types.h>
#include "env.h"
#include "pmu.h"
+#include <perf/cpumap.h>

enum {
HEADER_RESERVED = 0, /* always cleared */
--
2.47.0.199.ga7371fff76-goog