1// SPDX-License-Identifier: GPL-2.0
  2#include <test_progs.h>
  3
  4static volatile int sigusr1_received = 0;
  5
  6static void sigusr1_handler(int signum)
  7{
  8	sigusr1_received++;
  9}
 10
 11static void test_send_signal_common(struct perf_event_attr *attr,
 12				    int prog_type,
 13				    const char *test_name)
 14{
 15	int err = -1, pmu_fd, prog_fd, info_map_fd, status_map_fd;
 16	const char *file = "./test_send_signal_kern.o";
 17	struct bpf_object *obj = NULL;
 18	int pipe_c2p[2], pipe_p2c[2];
 19	__u32 key = 0, duration = 0;
 20	char buf[256];
 21	pid_t pid;
 22	__u64 val;
 23
 24	if (CHECK(pipe(pipe_c2p), test_name,
 25		  "pipe pipe_c2p error: %s\n", strerror(errno)))
 26		return;
 27
 28	if (CHECK(pipe(pipe_p2c), test_name,
 29		  "pipe pipe_p2c error: %s\n", strerror(errno))) {
 30		close(pipe_c2p[0]);
 31		close(pipe_c2p[1]);
 32		return;
 33	}
 34
 35	pid = fork();
 36	if (CHECK(pid < 0, test_name, "fork error: %s\n", strerror(errno))) {
 37		close(pipe_c2p[0]);
 38		close(pipe_c2p[1]);
 39		close(pipe_p2c[0]);
 40		close(pipe_p2c[1]);
 41		return;
 42	}
 43
 44	if (pid == 0) {
 45		/* install signal handler and notify parent */
 46		signal(SIGUSR1, sigusr1_handler);
 47
 48		close(pipe_c2p[0]); /* close read */
 49		close(pipe_p2c[1]); /* close write */
 50
 51		/* notify parent signal handler is installed */
 52		write(pipe_c2p[1], buf, 1);
 53
 54		/* make sure parent enabled bpf program to send_signal */
 55		read(pipe_p2c[0], buf, 1);
 56
 57		/* wait a little for signal handler */
 58		sleep(1);
 59
 60		if (sigusr1_received)
 61			write(pipe_c2p[1], "2", 1);
 62		else
 63			write(pipe_c2p[1], "0", 1);
 64
 65		/* wait for parent notification and exit */
 66		read(pipe_p2c[0], buf, 1);
 67
 68		close(pipe_c2p[1]);
 69		close(pipe_p2c[0]);
 70		exit(0);
 71	}
 72
 73	close(pipe_c2p[1]); /* close write */
 74	close(pipe_p2c[0]); /* close read */
 75
 76	err = bpf_prog_load(file, prog_type, &obj, &prog_fd);
 77	if (CHECK(err < 0, test_name, "bpf_prog_load error: %s\n",
 78		  strerror(errno)))
 79		goto prog_load_failure;
 80
 81	pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
 82			 -1 /* group id */, 0 /* flags */);
 83	if (CHECK(pmu_fd < 0, test_name, "perf_event_open error: %s\n",
 84		  strerror(errno))) {
 85		err = -1;
 86		goto close_prog;
 87	}
 88
 89	err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
 90	if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_enable error: %s\n",
 91		  strerror(errno)))
 92		goto disable_pmu;
 93
 94	err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
 95	if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_set_bpf error: %s\n",
 96		  strerror(errno)))
 97		goto disable_pmu;
 98
 99	err = -1;
100	info_map_fd = bpf_object__find_map_fd_by_name(obj, "info_map");
101	if (CHECK(info_map_fd < 0, test_name, "find map %s error\n", "info_map"))
102		goto disable_pmu;
103
104	status_map_fd = bpf_object__find_map_fd_by_name(obj, "status_map");
105	if (CHECK(status_map_fd < 0, test_name, "find map %s error\n", "status_map"))
106		goto disable_pmu;
107
108	/* wait until child signal handler installed */
109	read(pipe_c2p[0], buf, 1);
110
111	/* trigger the bpf send_signal */
112	key = 0;
113	val = (((__u64)(SIGUSR1)) << 32) | pid;
114	bpf_map_update_elem(info_map_fd, &key, &val, 0);
115
116	/* notify child that bpf program can send_signal now */
117	write(pipe_p2c[1], buf, 1);
118
119	/* wait for result */
120	err = read(pipe_c2p[0], buf, 1);
121	if (CHECK(err < 0, test_name, "reading pipe error: %s\n", strerror(errno)))
122		goto disable_pmu;
123	if (CHECK(err == 0, test_name, "reading pipe error: size 0\n")) {
124		err = -1;
125		goto disable_pmu;
126	}
127
128	CHECK(buf[0] != '2', test_name, "incorrect result\n");
129
130	/* notify child safe to exit */
131	write(pipe_p2c[1], buf, 1);
132
133disable_pmu:
134	close(pmu_fd);
135close_prog:
136	bpf_object__close(obj);
137prog_load_failure:
138	close(pipe_c2p[0]);
139	close(pipe_p2c[1]);
140	wait(NULL);
141}
142
143static void test_send_signal_tracepoint(void)
144{
145	const char *id_path = "/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id";
146	struct perf_event_attr attr = {
147		.type = PERF_TYPE_TRACEPOINT,
148		.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN,
149		.sample_period = 1,
150		.wakeup_events = 1,
151	};
152	__u32 duration = 0;
153	int bytes, efd;
154	char buf[256];
155
156	efd = open(id_path, O_RDONLY, 0);
157	if (CHECK(efd < 0, "tracepoint",
158		  "open syscalls/sys_enter_nanosleep/id failure: %s\n",
159		  strerror(errno)))
160		return;
161
162	bytes = read(efd, buf, sizeof(buf));
163	close(efd);
164	if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "tracepoint",
165		  "read syscalls/sys_enter_nanosleep/id failure: %s\n",
166		  strerror(errno)))
167		return;
168
169	attr.config = strtol(buf, NULL, 0);
170
171	test_send_signal_common(&attr, BPF_PROG_TYPE_TRACEPOINT, "tracepoint");
172}
173
174static void test_send_signal_perf(void)
175{
176	struct perf_event_attr attr = {
177		.sample_period = 1,
178		.type = PERF_TYPE_SOFTWARE,
179		.config = PERF_COUNT_SW_CPU_CLOCK,
180	};
181
182	test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT,
183				"perf_sw_event");
184}
185
186static void test_send_signal_nmi(void)
187{
188	struct perf_event_attr attr = {
189		.sample_freq = 50,
190		.freq = 1,
191		.type = PERF_TYPE_HARDWARE,
192		.config = PERF_COUNT_HW_CPU_CYCLES,
193	};
194	int pmu_fd;
195
196	/* Some setups (e.g. virtual machines) might run with hardware
197	 * perf events disabled. If this is the case, skip this test.
198	 */
199	pmu_fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */,
200			 -1 /* cpu */, -1 /* group_fd */, 0 /* flags */);
201	if (pmu_fd == -1) {
202		if (errno == ENOENT) {
203			printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n",
204			       __func__);
205			test__skip();
206			return;
207		}
208		/* Let the test fail with a more informative message */
209	} else {
210		close(pmu_fd);
211	}
212
213	test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT,
214				"perf_hw_event");
215}
216
217void test_send_signal(void)
218{
219	if (test__start_subtest("send_signal_tracepoint"))
220		test_send_signal_tracepoint();
221	if (test__start_subtest("send_signal_perf"))
222		test_send_signal_perf();
223	if (test__start_subtest("send_signal_nmi"))
224		test_send_signal_nmi();
225}