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}