1#include "evlist.h"
2#include "evsel.h"
3#include "cpumap.h"
4#include "parse-events.h"
5#include <api/fs/fs.h>
6#include "util.h"
7#include "cloexec.h"
8
9typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
10
11static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
12{
13	struct perf_evlist *evlist;
14	struct perf_evsel *evsel;
15	unsigned long flags = perf_event_open_cloexec_flag();
16	int err = -EAGAIN, fd;
17	static pid_t pid = -1;
18
19	evlist = perf_evlist__new();
20	if (!evlist)
21		return -ENOMEM;
22
23	if (parse_events(evlist, str))
24		goto out_delete;
25
26	evsel = perf_evlist__first(evlist);
27
28	while (1) {
29		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
30		if (fd < 0) {
31			if (pid == -1 && errno == EACCES) {
32				pid = 0;
33				continue;
34			}
35			goto out_delete;
36		}
37		break;
38	}
39	close(fd);
40
41	fn(evsel);
42
43	fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
44	if (fd < 0) {
45		if (errno == EINVAL)
46			err = -EINVAL;
47		goto out_delete;
48	}
49	close(fd);
50	err = 0;
51
52out_delete:
53	perf_evlist__delete(evlist);
54	return err;
55}
56
57static bool perf_probe_api(setup_probe_fn_t fn)
58{
59	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
60	struct cpu_map *cpus;
61	int cpu, ret, i = 0;
62
63	cpus = cpu_map__new(NULL);
64	if (!cpus)
65		return false;
66	cpu = cpus->map[0];
67	cpu_map__delete(cpus);
68
69	do {
70		ret = perf_do_probe_api(fn, cpu, try[i++]);
71		if (!ret)
72			return true;
73	} while (ret == -EAGAIN && try[i]);
74
75	return false;
76}
77
78static void perf_probe_sample_identifier(struct perf_evsel *evsel)
79{
80	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
81}
82
83static void perf_probe_comm_exec(struct perf_evsel *evsel)
84{
85	evsel->attr.comm_exec = 1;
86}
87
88bool perf_can_sample_identifier(void)
89{
90	return perf_probe_api(perf_probe_sample_identifier);
91}
92
93static bool perf_can_comm_exec(void)
94{
95	return perf_probe_api(perf_probe_comm_exec);
96}
97
98void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
99{
100	struct perf_evsel *evsel;
101	bool use_sample_identifier = false;
102	bool use_comm_exec;
103
104	/*
105	 * Set the evsel leader links before we configure attributes,
106	 * since some might depend on this info.
107	 */
108	if (opts->group)
109		perf_evlist__set_leader(evlist);
110
111	if (evlist->cpus->map[0] < 0)
112		opts->no_inherit = true;
113
114	use_comm_exec = perf_can_comm_exec();
115
116	evlist__for_each(evlist, evsel) {
117		perf_evsel__config(evsel, opts);
118		if (evsel->tracking && use_comm_exec)
119			evsel->attr.comm_exec = 1;
120	}
121
122	if (evlist->nr_entries > 1) {
123		struct perf_evsel *first = perf_evlist__first(evlist);
124
125		evlist__for_each(evlist, evsel) {
126			if (evsel->attr.sample_type == first->attr.sample_type)
127				continue;
128			use_sample_identifier = perf_can_sample_identifier();
129			break;
130		}
131		evlist__for_each(evlist, evsel)
132			perf_evsel__set_sample_id(evsel, use_sample_identifier);
133	}
134
135	perf_evlist__set_id_pos(evlist);
136}
137
138static int get_max_rate(unsigned int *rate)
139{
140	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
141}
142
143static int record_opts__config_freq(struct record_opts *opts)
144{
145	bool user_freq = opts->user_freq != UINT_MAX;
146	unsigned int max_rate;
147
148	if (opts->user_interval != ULLONG_MAX)
149		opts->default_interval = opts->user_interval;
150	if (user_freq)
151		opts->freq = opts->user_freq;
152
153	/*
154	 * User specified count overrides default frequency.
155	 */
156	if (opts->default_interval)
157		opts->freq = 0;
158	else if (opts->freq) {
159		opts->default_interval = opts->freq;
160	} else {
161		pr_err("frequency and count are zero, aborting\n");
162		return -1;
163	}
164
165	if (get_max_rate(&max_rate))
166		return 0;
167
168	/*
169	 * User specified frequency is over current maximum.
170	 */
171	if (user_freq && (max_rate < opts->freq)) {
172		pr_err("Maximum frequency rate (%u) reached.\n"
173		   "Please use -F freq option with lower value or consider\n"
174		   "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
175		   max_rate);
176		return -1;
177	}
178
179	/*
180	 * Default frequency is over current maximum.
181	 */
182	if (max_rate < opts->freq) {
183		pr_warning("Lowering default frequency rate to %u.\n"
184			   "Please consider tweaking "
185			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
186			   max_rate);
187		opts->freq = max_rate;
188	}
189
190	return 0;
191}
192
193int record_opts__config(struct record_opts *opts)
194{
195	return record_opts__config_freq(opts);
196}
197
198bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
199{
200	struct perf_evlist *temp_evlist;
201	struct perf_evsel *evsel;
202	int err, fd, cpu;
203	bool ret = false;
204	pid_t pid = -1;
205
206	temp_evlist = perf_evlist__new();
207	if (!temp_evlist)
208		return false;
209
210	err = parse_events(temp_evlist, str);
211	if (err)
212		goto out_delete;
213
214	evsel = perf_evlist__last(temp_evlist);
215
216	if (!evlist || cpu_map__empty(evlist->cpus)) {
217		struct cpu_map *cpus = cpu_map__new(NULL);
218
219		cpu =  cpus ? cpus->map[0] : 0;
220		cpu_map__delete(cpus);
221	} else {
222		cpu = evlist->cpus->map[0];
223	}
224
225	while (1) {
226		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
227					 perf_event_open_cloexec_flag());
228		if (fd < 0) {
229			if (pid == -1 && errno == EACCES) {
230				pid = 0;
231				continue;
232			}
233			goto out_delete;
234		}
235		break;
236	}
237	close(fd);
238	ret = true;
239
240out_delete:
241	perf_evlist__delete(temp_evlist);
242	return ret;
243}
244