1 /* SPDX-License-Identifier: GPL-2.0 */
4 #include "util/cloexec.h"
5 #include "util/evlist.h"
6 #include "util/evsel.h"
7 #include "util/parse-events.h"
8 #include "util/perf_api_probe.h"
9 #include <perf/cpumap.h>
12 typedef void (*setup_probe_fn_t)(struct evsel *evsel);
14 static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
16 struct evlist *evlist;
18 unsigned long flags = perf_event_open_cloexec_flag();
19 int err = -EAGAIN, fd;
20 static pid_t pid = -1;
22 evlist = evlist__new();
26 if (parse_events(evlist, str, NULL))
29 evsel = evlist__first(evlist);
32 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);
34 if (pid == -1 && errno == EACCES) {
46 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);
56 evlist__delete(evlist);
60 static bool perf_probe_api(setup_probe_fn_t fn)
62 const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
63 struct perf_cpu_map *cpus;
66 cpus = perf_cpu_map__new(NULL);
70 perf_cpu_map__put(cpus);
73 ret = perf_do_probe_api(fn, cpu, try[i++]);
76 } while (ret == -EAGAIN && try[i]);
81 static void perf_probe_sample_identifier(struct evsel *evsel)
83 evsel->core.attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
86 static void perf_probe_comm_exec(struct evsel *evsel)
88 evsel->core.attr.comm_exec = 1;
91 static void perf_probe_context_switch(struct evsel *evsel)
93 evsel->core.attr.context_switch = 1;
96 static void perf_probe_text_poke(struct evsel *evsel)
98 evsel->core.attr.text_poke = 1;
101 static void perf_probe_build_id(struct evsel *evsel)
103 evsel->core.attr.build_id = 1;
106 static void perf_probe_cgroup(struct evsel *evsel)
108 evsel->core.attr.cgroup = 1;
111 bool perf_can_sample_identifier(void)
113 return perf_probe_api(perf_probe_sample_identifier);
116 bool perf_can_comm_exec(void)
118 return perf_probe_api(perf_probe_comm_exec);
121 bool perf_can_record_switch_events(void)
123 return perf_probe_api(perf_probe_context_switch);
126 bool perf_can_record_text_poke_events(void)
128 return perf_probe_api(perf_probe_text_poke);
131 bool perf_can_record_cpu_wide(void)
133 struct perf_event_attr attr = {
134 .type = PERF_TYPE_SOFTWARE,
135 .config = PERF_COUNT_SW_CPU_CLOCK,
138 struct perf_cpu_map *cpus;
141 cpus = perf_cpu_map__new(NULL);
145 perf_cpu_map__put(cpus);
147 fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
156 * Architectures are expected to know if AUX area sampling is supported by the
157 * hardware. Here we check for kernel support.
159 bool perf_can_aux_sample(void)
161 struct perf_event_attr attr = {
162 .size = sizeof(struct perf_event_attr),
165 * Non-zero value causes the kernel to calculate the effective
166 * attribute size up to that byte.
168 .aux_sample_size = 1,
172 fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
174 * If the kernel attribute is big enough to contain aux_sample_size
175 * then we assume that it is supported. We are relying on the kernel to
176 * validate the attribute size before anything else that could be wrong.
178 if (fd < 0 && errno == E2BIG)
186 bool perf_can_record_build_id(void)
188 return perf_probe_api(perf_probe_build_id);
191 bool perf_can_record_cgroup(void)
193 return perf_probe_api(perf_probe_cgroup);