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 "bpf/libbpf_internal.h"
8 #include "test_perf_branches.skel.h"
9
10 static void check_good_sample(struct test_perf_branches *skel)
11 {
12 int written_global = skel->bss->written_global_out;
13 int required_size = skel->bss->required_size_out;
14 int written_stack = skel->bss->written_stack_out;
15 int pbe_size = sizeof(struct perf_branch_entry);
16 int duration = 0;
17
18 if (CHECK(!skel->bss->valid, "output not valid",
19 "no valid sample from prog"))
20 return;
21
22 /*
23 * It's hard to validate the contents of the branch entries b/c it
24 * would require some kind of disassembler and also encoding the
25 * valid jump instructions for supported architectures. So just check
26 * the easy stuff for now.
27 */
28 CHECK(required_size <= 0, "read_branches_size", "err %d\n", required_size);
29 CHECK(written_stack < 0, "read_branches_stack", "err %d\n", written_stack);
30 CHECK(written_stack % pbe_size != 0, "read_branches_stack",
31 "stack bytes written=%d not multiple of struct size=%d\n",
32 written_stack, pbe_size);
33 CHECK(written_global < 0, "read_branches_global", "err %d\n", written_global);
34 CHECK(written_global % pbe_size != 0, "read_branches_global",
35 "global bytes written=%d not multiple of struct size=%d\n",
36 written_global, pbe_size);
37 CHECK(written_global < written_stack, "read_branches_size",
38 "written_global=%d < written_stack=%d\n", written_global, written_stack);
39 }
40
41 static void check_bad_sample(struct test_perf_branches *skel)
42 {
43 int written_global = skel->bss->written_global_out;
44 int required_size = skel->bss->required_size_out;
45 int written_stack = skel->bss->written_stack_out;
46 int duration = 0;
47
48 if (CHECK(!skel->bss->valid, "output not valid",
49 "no valid sample from prog"))
50 return;
51
52 CHECK((required_size != -EINVAL && required_size != -ENOENT),
53 "read_branches_size", "err %d\n", required_size);
54 CHECK((written_stack != -EINVAL && written_stack != -ENOENT),
55 "read_branches_stack", "written %d\n", written_stack);
56 CHECK((written_global != -EINVAL && written_global != -ENOENT),
57 "read_branches_global", "written %d\n", written_global);
58 }
59
60 static void test_perf_branches_common(int perf_fd,
61 void (*cb)(struct test_perf_branches *))
62 {
63 struct test_perf_branches *skel;
64 int err, i, duration = 0;
65 bool detached = false;
66 struct bpf_link *link;
67 volatile int j = 0;
68 cpu_set_t cpu_set;
69
70 skel = test_perf_branches__open_and_load();
71 if (CHECK(!skel, "test_perf_branches_load",
72 "perf_branches skeleton failed\n"))
73 return;
74
75 /* attach perf_event */
76 link = bpf_program__attach_perf_event(skel->progs.perf_branches, perf_fd);
77 if (!ASSERT_OK_PTR(link, "attach_perf_event"))
78 goto out_destroy_skel;
79
80 /* generate some branches on cpu 0 */
81 CPU_ZERO(&cpu_set);
82 CPU_SET(0, &cpu_set);
83 err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
84 if (CHECK(err, "set_affinity", "cpu #0, err %d\n", err))
85 goto out_destroy;
86 /* spin the loop for a while (random high number) */
87 for (i = 0; i < 1000000; ++i)
88 ++j;
89
90 test_perf_branches__detach(skel);
91 detached = true;
92
93 cb(skel);
94 out_destroy:
95 bpf_link__destroy(link);
96 out_destroy_skel:
97 if (!detached)
98 test_perf_branches__detach(skel);
99 test_perf_branches__destroy(skel);
100 }
101
102 static void test_perf_branches_hw(void)
103 {
104 struct perf_event_attr attr = {0};
105 int duration = 0;
106 int pfd;
107
108 /* create perf event */
109 attr.size = sizeof(attr);
110 attr.type = PERF_TYPE_HARDWARE;
111 attr.config = PERF_COUNT_HW_CPU_CYCLES;
112 attr.freq = 1;
113 attr.sample_freq = 1000;
114 attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
115 attr.branch_sample_type = PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;
116 pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
117
118 /*
119 * Some setups don't support branch records (virtual machines, !x86),
120 * so skip test in this case.
121 */
122 if (pfd < 0) {
123 if (errno == ENOENT || errno == EOPNOTSUPP) {
124 printf("%s:SKIP:no PERF_SAMPLE_BRANCH_STACK\n",
125 __func__);
126 test__skip();
127 return;
128 }
129 if (CHECK(pfd < 0, "perf_event_open", "err %d errno %d\n",
130 pfd, errno))
131 return;
132 }
133
134 test_perf_branches_common(pfd, check_good_sample);
135
136 close(pfd);
137 }
138
139 /*
140 * Tests negative case -- run bpf_read_branch_records() on improperly configured
141 * perf event.
142 */
143 static void test_perf_branches_no_hw(void)
144 {
145 struct perf_event_attr attr = {0};
146 int duration = 0;
147 int pfd;
148
149 /* create perf event */
150 attr.size = sizeof(attr);
151 attr.type = PERF_TYPE_SOFTWARE;
152 attr.config = PERF_COUNT_SW_CPU_CLOCK;
153 attr.freq = 1;
154 attr.sample_freq = 1000;
155 pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
156 if (CHECK(pfd < 0, "perf_event_open", "err %d\n", pfd))
157 return;
158
159 test_perf_branches_common(pfd, check_bad_sample);
160
161 close(pfd);
162 }
163
164 void test_perf_branches(void)
165 {
166 if (test__start_subtest("perf_branches_hw"))
167 test_perf_branches_hw();
168 if (test__start_subtest("perf_branches_no_hw"))
169 test_perf_branches_no_hw();
170 }
171
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