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 14 int sigio_count, sigtrap_count; 15 16 static void handle_sigio(int sig __always_unused) 17 { 18 ++sigio_count; 19 } 20 21 static 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 29 static noinline int test_function(void) 30 { 31 asm volatile (""); 32 return 0; 33 } 34 35 void 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"); 127 128 cleanup: 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