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, struct perf_cpu 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.cpu, -1, flags);
34 if (pid == -1 && errno == EACCES) {
46 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu.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;
67 cpus = perf_cpu_map__new(NULL);
70 cpu = perf_cpu_map__cpu(cpus, 0);
71 perf_cpu_map__put(cpus);
74 ret = perf_do_probe_api(fn, cpu, try[i++]);
77 } while (ret == -EAGAIN && try[i]);
82 static void perf_probe_sample_identifier(struct evsel *evsel)
84 evsel->core.attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
87 static void perf_probe_comm_exec(struct evsel *evsel)
89 evsel->core.attr.comm_exec = 1;
92 static void perf_probe_context_switch(struct evsel *evsel)
94 evsel->core.attr.context_switch = 1;
97 static void perf_probe_text_poke(struct evsel *evsel)
99 evsel->core.attr.text_poke = 1;
102 static void perf_probe_build_id(struct evsel *evsel)
104 evsel->core.attr.build_id = 1;
107 static void perf_probe_cgroup(struct evsel *evsel)
109 evsel->core.attr.cgroup = 1;
112 bool perf_can_sample_identifier(void)
114 return perf_probe_api(perf_probe_sample_identifier);
117 bool perf_can_comm_exec(void)
119 return perf_probe_api(perf_probe_comm_exec);
122 bool perf_can_record_switch_events(void)
124 return perf_probe_api(perf_probe_context_switch);
127 bool perf_can_record_text_poke_events(void)
129 return perf_probe_api(perf_probe_text_poke);
132 bool perf_can_record_cpu_wide(void)
134 struct perf_event_attr attr = {
135 .type = PERF_TYPE_SOFTWARE,
136 .config = PERF_COUNT_SW_CPU_CLOCK,
139 struct perf_cpu_map *cpus;
143 cpus = perf_cpu_map__new(NULL);
147 cpu = perf_cpu_map__cpu(cpus, 0);
148 perf_cpu_map__put(cpus);
150 fd = sys_perf_event_open(&attr, -1, cpu.cpu, -1, 0);
159 * Architectures are expected to know if AUX area sampling is supported by the
160 * hardware. Here we check for kernel support.
162 bool perf_can_aux_sample(void)
164 struct perf_event_attr attr = {
165 .size = sizeof(struct perf_event_attr),
168 * Non-zero value causes the kernel to calculate the effective
169 * attribute size up to that byte.
171 .aux_sample_size = 1,
175 fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
177 * If the kernel attribute is big enough to contain aux_sample_size
178 * then we assume that it is supported. We are relying on the kernel to
179 * validate the attribute size before anything else that could be wrong.
181 if (fd < 0 && errno == E2BIG)
189 bool perf_can_record_build_id(void)
191 return perf_probe_api(perf_probe_build_id);
194 bool perf_can_record_cgroup(void)
196 return perf_probe_api(perf_probe_cgroup);