xref: /openbmc/linux/tools/testing/selftests/bpf/prog_tests/perf_buffer.c (revision 03ab8e6297acd1bc0eedaa050e2a1635c576fd11)
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  #include "test_perf_buffer.skel.h"
8  #include "bpf/libbpf_internal.h"
9  
10  static int duration;
11  
12  /* AddressSanitizer sometimes crashes due to data dereference below, due to
13   * this being mmap()'ed memory. Disable instrumentation with
14   * no_sanitize_address attribute
15   */
16  __attribute__((no_sanitize_address))
on_sample(void * ctx,int cpu,void * data,__u32 size)17  static void on_sample(void *ctx, int cpu, void *data, __u32 size)
18  {
19  	int cpu_data = *(int *)data, duration = 0;
20  	cpu_set_t *cpu_seen = ctx;
21  
22  	if (cpu_data != cpu)
23  		CHECK(cpu_data != cpu, "check_cpu_data",
24  		      "cpu_data %d != cpu %d\n", cpu_data, cpu);
25  
26  	CPU_SET(cpu, cpu_seen);
27  }
28  
trigger_on_cpu(int cpu)29  int trigger_on_cpu(int cpu)
30  {
31  	cpu_set_t cpu_set;
32  	int err;
33  
34  	CPU_ZERO(&cpu_set);
35  	CPU_SET(cpu, &cpu_set);
36  
37  	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
38  	if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", cpu, err))
39  		return err;
40  
41  	usleep(1);
42  
43  	return 0;
44  }
45  
serial_test_perf_buffer(void)46  void serial_test_perf_buffer(void)
47  {
48  	int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
49  	int zero = 0, my_pid = getpid();
50  	struct test_perf_buffer *skel;
51  	cpu_set_t cpu_seen;
52  	struct perf_buffer *pb;
53  	int last_fd = -1, fd;
54  	bool *online;
55  
56  	nr_cpus = libbpf_num_possible_cpus();
57  	if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
58  		return;
59  
60  	err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
61  				  &online, &on_len);
62  	if (CHECK(err, "nr_on_cpus", "err %d\n", err))
63  		return;
64  
65  	for (i = 0; i < on_len; i++)
66  		if (online[i])
67  			nr_on_cpus++;
68  
69  	/* load program */
70  	skel = test_perf_buffer__open_and_load();
71  	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
72  		goto out_close;
73  
74  	err = bpf_map_update_elem(bpf_map__fd(skel->maps.my_pid_map), &zero, &my_pid, 0);
75  	if (!ASSERT_OK(err, "my_pid_update"))
76  		goto out_close;
77  
78  	/* attach probe */
79  	err = test_perf_buffer__attach(skel);
80  	if (CHECK(err, "attach_kprobe", "err %d\n", err))
81  		goto out_close;
82  
83  	/* set up perf buffer */
84  	pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1,
85  			      on_sample, NULL, &cpu_seen, NULL);
86  	if (!ASSERT_OK_PTR(pb, "perf_buf__new"))
87  		goto out_close;
88  
89  	CHECK(perf_buffer__epoll_fd(pb) < 0, "epoll_fd",
90  	      "bad fd: %d\n", perf_buffer__epoll_fd(pb));
91  
92  	/* trigger kprobe on every CPU */
93  	CPU_ZERO(&cpu_seen);
94  	for (i = 0; i < nr_cpus; i++) {
95  		if (i >= on_len || !online[i]) {
96  			printf("skipping offline CPU #%d\n", i);
97  			continue;
98  		}
99  
100  		if (trigger_on_cpu(i))
101  			goto out_close;
102  	}
103  
104  	/* read perf buffer */
105  	err = perf_buffer__poll(pb, 100);
106  	if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
107  		goto out_free_pb;
108  
109  	if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
110  		  "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
111  		goto out_free_pb;
112  
113  	if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt",
114  		  "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus))
115  		goto out_close;
116  
117  	for (i = 0, j = 0; i < nr_cpus; i++) {
118  		if (i >= on_len || !online[i])
119  			continue;
120  
121  		fd = perf_buffer__buffer_fd(pb, j);
122  		CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
123  		last_fd = fd;
124  
125  		err = perf_buffer__consume_buffer(pb, j);
126  		if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
127  			goto out_close;
128  
129  		CPU_CLR(i, &cpu_seen);
130  		if (trigger_on_cpu(i))
131  			goto out_close;
132  
133  		err = perf_buffer__consume_buffer(pb, j);
134  		if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err))
135  			goto out_close;
136  
137  		if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
138  			goto out_close;
139  		j++;
140  	}
141  
142  out_free_pb:
143  	perf_buffer__free(pb);
144  out_close:
145  	test_perf_buffer__destroy(skel);
146  	free(online);
147  }
148