1// SPDX-License-Identifier: GPL-2.0
2#define _GNU_SOURCE
3
4#include <test_progs.h>
5#include "test_perf_skip.skel.h"
6#include <linux/compiler.h>
7#include <linux/hw_breakpoint.h>
8#include <sys/mman.h>
9
10#ifndef TRAP_PERF
11#define TRAP_PERF 6
12#endif
13
14int sigio_count, sigtrap_count;
15
16static void handle_sigio(int sig __always_unused)
17{
18	++sigio_count;
19}
20
21static void handle_sigtrap(int signum __always_unused,
22			   siginfo_t *info,
23			   void *ucontext __always_unused)
24{
25	ASSERT_EQ(info->si_code, TRAP_PERF, "si_code");
26	++sigtrap_count;
27}
28
29static noinline int test_function(void)
30{
31	asm volatile ("");
32	return 0;
33}
34
35void serial_test_perf_skip(void)
36{
37	struct sigaction action = {};
38	struct sigaction previous_sigtrap;
39	sighandler_t previous_sigio = SIG_ERR;
40	struct test_perf_skip *skel = NULL;
41	struct perf_event_attr attr = {};
42	int perf_fd = -1;
43	int err;
44	struct f_owner_ex owner;
45	struct bpf_link *prog_link = NULL;
46
47	action.sa_flags = SA_SIGINFO | SA_NODEFER;
48	action.sa_sigaction = handle_sigtrap;
49	sigemptyset(&action.sa_mask);
50	if (!ASSERT_OK(sigaction(SIGTRAP, &action, &previous_sigtrap), "sigaction"))
51		return;
52
53	previous_sigio = signal(SIGIO, handle_sigio);
54	if (!ASSERT_NEQ(previous_sigio, SIG_ERR, "signal"))
55		goto cleanup;
56
57	skel = test_perf_skip__open_and_load();
58	if (!ASSERT_OK_PTR(skel, "skel_load"))
59		goto cleanup;
60
61	attr.type = PERF_TYPE_BREAKPOINT;
62	attr.size = sizeof(attr);
63	attr.bp_type = HW_BREAKPOINT_X;
64	attr.bp_addr = (uintptr_t)test_function;
65	attr.bp_len = sizeof(long);
66	attr.sample_period = 1;
67	attr.sample_type = PERF_SAMPLE_IP;
68	attr.pinned = 1;
69	attr.exclude_kernel = 1;
70	attr.exclude_hv = 1;
71	attr.precise_ip = 3;
72	attr.sigtrap = 1;
73	attr.remove_on_exec = 1;
74
75	perf_fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
76	if (perf_fd < 0 && (errno == ENOENT || errno == EOPNOTSUPP)) {
77		printf("SKIP:no PERF_TYPE_BREAKPOINT/HW_BREAKPOINT_X\n");
78		test__skip();
79		goto cleanup;
80	}
81	if (!ASSERT_OK(perf_fd < 0, "perf_event_open"))
82		goto cleanup;
83
84	/* Configure the perf event to signal on sample. */
85	err = fcntl(perf_fd, F_SETFL, O_ASYNC);
86	if (!ASSERT_OK(err, "fcntl(F_SETFL, O_ASYNC)"))
87		goto cleanup;
88
89	owner.type = F_OWNER_TID;
90	owner.pid = syscall(__NR_gettid);
91	err = fcntl(perf_fd, F_SETOWN_EX, &owner);
92	if (!ASSERT_OK(err, "fcntl(F_SETOWN_EX)"))
93		goto cleanup;
94
95	/* Allow at most one sample. A sample rejected by bpf should
96	 * not count against this.
97	 */
98	err = ioctl(perf_fd, PERF_EVENT_IOC_REFRESH, 1);
99	if (!ASSERT_OK(err, "ioctl(PERF_EVENT_IOC_REFRESH)"))
100		goto cleanup;
101
102	prog_link = bpf_program__attach_perf_event(skel->progs.handler, perf_fd);
103	if (!ASSERT_OK_PTR(prog_link, "bpf_program__attach_perf_event"))
104		goto cleanup;
105
106	/* Configure the bpf program to suppress the sample. */
107	skel->bss->ip = (uintptr_t)test_function;
108	test_function();
109
110	ASSERT_EQ(sigio_count, 0, "sigio_count");
111	ASSERT_EQ(sigtrap_count, 0, "sigtrap_count");
112
113	/* Configure the bpf program to allow the sample. */
114	skel->bss->ip = 0;
115	test_function();
116
117	ASSERT_EQ(sigio_count, 1, "sigio_count");
118	ASSERT_EQ(sigtrap_count, 1, "sigtrap_count");
119
120	/* Test that the sample above is the only one allowed (by perf, not
121	 * by bpf)
122	 */
123	test_function();
124
125	ASSERT_EQ(sigio_count, 1, "sigio_count");
126	ASSERT_EQ(sigtrap_count, 1, "sigtrap_count");
127
128cleanup:
129	bpf_link__destroy(prog_link);
130	if (perf_fd >= 0)
131		close(perf_fd);
132	test_perf_skip__destroy(skel);
133
134	if (previous_sigio != SIG_ERR)
135		signal(SIGIO, previous_sigio);
136	sigaction(SIGTRAP, &previous_sigtrap, NULL);
137}
138