GNU Linux-libre 6.6.15-gnu
[releases.git] / samples / bpf / trace_event_user.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
3  */
4 #include <stdio.h>
5 #include <unistd.h>
6 #include <stdlib.h>
7 #include <stdbool.h>
8 #include <string.h>
9 #include <linux/perf_event.h>
10 #include <linux/bpf.h>
11 #include <signal.h>
12 #include <errno.h>
13 #include <sys/resource.h>
14 #include <bpf/bpf.h>
15 #include <bpf/libbpf.h>
16 #include "perf-sys.h"
17 #include "trace_helpers.h"
18
19 #define SAMPLE_FREQ 50
20
21 static int pid;
22 /* counts, stackmap */
23 static int map_fd[2];
24 struct bpf_program *prog;
25 static bool sys_read_seen, sys_write_seen;
26
27 static void print_ksym(__u64 addr)
28 {
29         struct ksym *sym;
30
31         if (!addr)
32                 return;
33         sym = ksym_search(addr);
34         if (!sym) {
35                 printf("ksym not found. Is kallsyms loaded?\n");
36                 return;
37         }
38
39         printf("%s;", sym->name);
40         if (!strstr(sym->name, "sys_read"))
41                 sys_read_seen = true;
42         else if (!strstr(sym->name, "sys_write"))
43                 sys_write_seen = true;
44 }
45
46 static void print_addr(__u64 addr)
47 {
48         if (!addr)
49                 return;
50         printf("%llx;", addr);
51 }
52
53 #define TASK_COMM_LEN 16
54
55 struct key_t {
56         char comm[TASK_COMM_LEN];
57         __u32 kernstack;
58         __u32 userstack;
59 };
60
61 static void print_stack(struct key_t *key, __u64 count)
62 {
63         __u64 ip[PERF_MAX_STACK_DEPTH] = {};
64         static bool warned;
65         int i;
66
67         printf("%3lld %s;", count, key->comm);
68         if (bpf_map_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
69                 printf("---;");
70         } else {
71                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
72                         print_ksym(ip[i]);
73         }
74         printf("-;");
75         if (bpf_map_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
76                 printf("---;");
77         } else {
78                 for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
79                         print_addr(ip[i]);
80         }
81         if (count < 6)
82                 printf("\r");
83         else
84                 printf("\n");
85
86         if (key->kernstack == -EEXIST && !warned) {
87                 printf("stackmap collisions seen. Consider increasing size\n");
88                 warned = true;
89         } else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
90                 printf("err stackid %d %d\n", key->kernstack, key->userstack);
91         }
92 }
93
94 static void err_exit(int err)
95 {
96         kill(pid, SIGKILL);
97         exit(err);
98 }
99
100 static void print_stacks(void)
101 {
102         struct key_t key = {}, next_key;
103         __u64 value;
104         __u32 stackid = 0, next_id;
105         int error = 1, fd = map_fd[0], stack_map = map_fd[1];
106
107         sys_read_seen = sys_write_seen = false;
108         while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
109                 bpf_map_lookup_elem(fd, &next_key, &value);
110                 print_stack(&next_key, value);
111                 bpf_map_delete_elem(fd, &next_key);
112                 key = next_key;
113         }
114         printf("\n");
115         if (!sys_read_seen || !sys_write_seen) {
116                 printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
117                 err_exit(error);
118         }
119
120         /* clear stack map */
121         while (bpf_map_get_next_key(stack_map, &stackid, &next_id) == 0) {
122                 bpf_map_delete_elem(stack_map, &next_id);
123                 stackid = next_id;
124         }
125 }
126
127 static inline int generate_load(void)
128 {
129         if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
130                 printf("failed to generate some load with dd: %s\n", strerror(errno));
131                 return -1;
132         }
133
134         return 0;
135 }
136
137 static void test_perf_event_all_cpu(struct perf_event_attr *attr)
138 {
139         int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
140         struct bpf_link **links = calloc(nr_cpus, sizeof(struct bpf_link *));
141         int i, pmu_fd, error = 1;
142
143         if (!links) {
144                 printf("malloc of links failed\n");
145                 goto err;
146         }
147
148         /* system wide perf event, no need to inherit */
149         attr->inherit = 0;
150
151         /* open perf_event on all cpus */
152         for (i = 0; i < nr_cpus; i++) {
153                 pmu_fd = sys_perf_event_open(attr, -1, i, -1, 0);
154                 if (pmu_fd < 0) {
155                         printf("sys_perf_event_open failed\n");
156                         goto all_cpu_err;
157                 }
158                 links[i] = bpf_program__attach_perf_event(prog, pmu_fd);
159                 if (libbpf_get_error(links[i])) {
160                         printf("bpf_program__attach_perf_event failed\n");
161                         links[i] = NULL;
162                         close(pmu_fd);
163                         goto all_cpu_err;
164                 }
165         }
166
167         if (generate_load() < 0)
168                 goto all_cpu_err;
169
170         print_stacks();
171         error = 0;
172 all_cpu_err:
173         for (i--; i >= 0; i--)
174                 bpf_link__destroy(links[i]);
175 err:
176         free(links);
177         if (error)
178                 err_exit(error);
179 }
180
181 static void test_perf_event_task(struct perf_event_attr *attr)
182 {
183         struct bpf_link *link = NULL;
184         int pmu_fd, error = 1;
185
186         /* per task perf event, enable inherit so the "dd ..." command can be traced properly.
187          * Enabling inherit will cause bpf_perf_prog_read_time helper failure.
188          */
189         attr->inherit = 1;
190
191         /* open task bound event */
192         pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
193         if (pmu_fd < 0) {
194                 printf("sys_perf_event_open failed\n");
195                 goto err;
196         }
197         link = bpf_program__attach_perf_event(prog, pmu_fd);
198         if (libbpf_get_error(link)) {
199                 printf("bpf_program__attach_perf_event failed\n");
200                 link = NULL;
201                 close(pmu_fd);
202                 goto err;
203         }
204
205         if (generate_load() < 0)
206                 goto err;
207
208         print_stacks();
209         error = 0;
210 err:
211         bpf_link__destroy(link);
212         if (error)
213                 err_exit(error);
214 }
215
216 static void test_bpf_perf_event(void)
217 {
218         struct perf_event_attr attr_type_hw = {
219                 .sample_freq = SAMPLE_FREQ,
220                 .freq = 1,
221                 .type = PERF_TYPE_HARDWARE,
222                 .config = PERF_COUNT_HW_CPU_CYCLES,
223         };
224         struct perf_event_attr attr_type_sw = {
225                 .sample_freq = SAMPLE_FREQ,
226                 .freq = 1,
227                 .type = PERF_TYPE_SOFTWARE,
228                 .config = PERF_COUNT_SW_CPU_CLOCK,
229         };
230         struct perf_event_attr attr_hw_cache_l1d = {
231                 .sample_freq = SAMPLE_FREQ,
232                 .freq = 1,
233                 .type = PERF_TYPE_HW_CACHE,
234                 .config =
235                         PERF_COUNT_HW_CACHE_L1D |
236                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
237                         (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
238         };
239         struct perf_event_attr attr_hw_cache_branch_miss = {
240                 .sample_freq = SAMPLE_FREQ,
241                 .freq = 1,
242                 .type = PERF_TYPE_HW_CACHE,
243                 .config =
244                         PERF_COUNT_HW_CACHE_BPU |
245                         (PERF_COUNT_HW_CACHE_OP_READ << 8) |
246                         (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
247         };
248         struct perf_event_attr attr_type_raw = {
249                 .sample_freq = SAMPLE_FREQ,
250                 .freq = 1,
251                 .type = PERF_TYPE_RAW,
252                 /* Intel Instruction Retired */
253                 .config = 0xc0,
254         };
255         struct perf_event_attr attr_type_raw_lock_load = {
256                 .sample_freq = SAMPLE_FREQ,
257                 .freq = 1,
258                 .type = PERF_TYPE_RAW,
259                 /* Intel MEM_UOPS_RETIRED.LOCK_LOADS */
260                 .config = 0x21d0,
261                 /* Request to record lock address from PEBS */
262                 .sample_type = PERF_SAMPLE_ADDR,
263                 /* Record address value requires precise event */
264                 .precise_ip = 2,
265         };
266
267         printf("Test HW_CPU_CYCLES\n");
268         test_perf_event_all_cpu(&attr_type_hw);
269         test_perf_event_task(&attr_type_hw);
270
271         printf("Test SW_CPU_CLOCK\n");
272         test_perf_event_all_cpu(&attr_type_sw);
273         test_perf_event_task(&attr_type_sw);
274
275         printf("Test HW_CACHE_L1D\n");
276         test_perf_event_all_cpu(&attr_hw_cache_l1d);
277         test_perf_event_task(&attr_hw_cache_l1d);
278
279         printf("Test HW_CACHE_BPU\n");
280         test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
281         test_perf_event_task(&attr_hw_cache_branch_miss);
282
283         printf("Test Instruction Retired\n");
284         test_perf_event_all_cpu(&attr_type_raw);
285         test_perf_event_task(&attr_type_raw);
286
287         printf("Test Lock Load\n");
288         test_perf_event_all_cpu(&attr_type_raw_lock_load);
289         test_perf_event_task(&attr_type_raw_lock_load);
290
291         printf("*** PASS ***\n");
292 }
293
294
295 int main(int argc, char **argv)
296 {
297         struct bpf_object *obj = NULL;
298         char filename[256];
299         int error = 1;
300
301         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
302
303         signal(SIGINT, err_exit);
304         signal(SIGTERM, err_exit);
305
306         if (load_kallsyms()) {
307                 printf("failed to process /proc/kallsyms\n");
308                 goto cleanup;
309         }
310
311         obj = bpf_object__open_file(filename, NULL);
312         if (libbpf_get_error(obj)) {
313                 printf("opening BPF object file failed\n");
314                 obj = NULL;
315                 goto cleanup;
316         }
317
318         prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
319         if (!prog) {
320                 printf("finding a prog in obj file failed\n");
321                 goto cleanup;
322         }
323
324         /* load BPF program */
325         if (bpf_object__load(obj)) {
326                 printf("loading BPF object file failed\n");
327                 goto cleanup;
328         }
329
330         map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
331         map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
332         if (map_fd[0] < 0 || map_fd[1] < 0) {
333                 printf("finding a counts/stackmap map in obj file failed\n");
334                 goto cleanup;
335         }
336
337         pid = fork();
338         if (pid == 0) {
339                 read_trace_pipe();
340                 return 0;
341         } else if (pid == -1) {
342                 printf("couldn't spawn process\n");
343                 goto cleanup;
344         }
345
346         test_bpf_perf_event();
347         error = 0;
348
349 cleanup:
350         bpf_object__close(obj);
351         err_exit(error);
352 }