1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #include <pthread.h>
4 #include <sched.h>
5 #include <sys/socket.h>
6 #include <test_progs.h>
7
on_sample(void * ctx,int cpu,void * data,__u32 size)8 static void on_sample(void *ctx, int cpu, void *data, __u32 size)
9 {
10 int cpu_data = *(int *)data, duration = 0;
11 cpu_set_t *cpu_seen = ctx;
12
13 if (cpu_data != cpu)
14 CHECK(cpu_data != cpu, "check_cpu_data",
15 "cpu_data %d != cpu %d\n", cpu_data, cpu);
16
17 CPU_SET(cpu, cpu_seen);
18 }
19
test_perf_buffer(void)20 void test_perf_buffer(void)
21 {
22 int err, prog_fd, nr_cpus, i, duration = 0;
23 const char *prog_name = "kprobe/sys_nanosleep";
24 const char *file = "./test_perf_buffer.o";
25 struct perf_buffer_opts pb_opts = {};
26 struct bpf_map *perf_buf_map;
27 cpu_set_t cpu_set, cpu_seen;
28 struct bpf_program *prog;
29 struct bpf_object *obj;
30 struct perf_buffer *pb;
31 struct bpf_link *link;
32
33 nr_cpus = libbpf_num_possible_cpus();
34 if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
35 return;
36
37 /* load program */
38 err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
39 if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
40 return;
41
42 prog = bpf_object__find_program_by_title(obj, prog_name);
43 if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
44 goto out_close;
45
46 /* load map */
47 perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
48 if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
49 goto out_close;
50
51 /* attach kprobe */
52 link = bpf_program__attach_kprobe(prog, false /* retprobe */,
53 SYS_NANOSLEEP_KPROBE_NAME);
54 if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
55 goto out_close;
56
57 /* set up perf buffer */
58 pb_opts.sample_cb = on_sample;
59 pb_opts.ctx = &cpu_seen;
60 pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
61 if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
62 goto out_detach;
63
64 /* trigger kprobe on every CPU */
65 CPU_ZERO(&cpu_seen);
66 for (i = 0; i < nr_cpus; i++) {
67 CPU_ZERO(&cpu_set);
68 CPU_SET(i, &cpu_set);
69
70 err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
71 &cpu_set);
72 if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
73 i, err))
74 goto out_detach;
75
76 usleep(1);
77 }
78
79 /* read perf buffer */
80 err = perf_buffer__poll(pb, 100);
81 if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
82 goto out_free_pb;
83
84 if (CHECK(CPU_COUNT(&cpu_seen) != nr_cpus, "seen_cpu_cnt",
85 "expect %d, seen %d\n", nr_cpus, CPU_COUNT(&cpu_seen)))
86 goto out_free_pb;
87
88 out_free_pb:
89 perf_buffer__free(pb);
90 out_detach:
91 bpf_link__destroy(link);
92 out_close:
93 bpf_object__close(obj);
94 }
95
