diff --git a/tools/testing/selftests/bpf/prog_tests/perf_link.c b/tools/testing/selftests/bpf/prog_tests/perf_link.c new file mode 100644 index 000000000000..b1abd0c46607 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_link.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#define _GNU_SOURCE +#include +#include +#include +#include "test_perf_link.skel.h" + +static void burn_cpu(void) +{ + volatile int j = 0; + cpu_set_t cpu_set; + int i, err; + + /* generate some branches on cpu 0 */ + CPU_ZERO(&cpu_set); + CPU_SET(0, &cpu_set); + err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set); + ASSERT_OK(err, "set_thread_affinity"); + + /* spin the loop for a while (random high number) */ + for (i = 0; i < 1000000; ++i) + ++j; +} + +void test_perf_link(void) +{ + struct test_perf_link *skel = NULL; + struct perf_event_attr attr; + int pfd = -1, link_fd = -1, err; + int run_cnt_before, run_cnt_after; + struct bpf_link_info info; + __u32 info_len = sizeof(info); + + /* create perf event */ + memset(&attr, 0, sizeof(attr)); + attr.size = sizeof(attr); + attr.type = PERF_TYPE_SOFTWARE; + attr.config = PERF_COUNT_SW_CPU_CLOCK; + attr.freq = 1; + attr.sample_freq = 4000; + pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); + if (!ASSERT_GE(pfd, 0, "perf_fd")) + goto cleanup; + + skel = test_perf_link__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto cleanup; + + link_fd = bpf_link_create(bpf_program__fd(skel->progs.handler), pfd, + BPF_PERF_EVENT, NULL); + if (!ASSERT_GE(link_fd, 0, "link_fd")) + goto cleanup; + + memset(&info, 0, sizeof(info)); + err = bpf_obj_get_info_by_fd(link_fd, &info, &info_len); + if (!ASSERT_OK(err, "link_get_info")) + goto cleanup; + + ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type"); + ASSERT_GT(info.id, 0, "link_id"); + ASSERT_GT(info.prog_id, 0, "link_prog_id"); + + /* ensure we get at least one perf_event prog execution */ + burn_cpu(); + ASSERT_GT(skel->bss->run_cnt, 0, "run_cnt"); + + /* perf_event is still active, but we close link and BPF program + * shouldn't be executed anymore + */ + close(link_fd); + link_fd = -1; + + /* make sure there are no stragglers */ + kern_sync_rcu(); + + run_cnt_before = skel->bss->run_cnt; + burn_cpu(); + run_cnt_after = skel->bss->run_cnt; + + ASSERT_EQ(run_cnt_before, run_cnt_after, "run_cnt_before_after"); + +cleanup: + if (link_fd >= 0) + close(link_fd); + if (pfd >= 0) + close(pfd); + test_perf_link__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_link.c b/tools/testing/selftests/bpf/progs/test_perf_link.c new file mode 100644 index 000000000000..c1db9fd98d0c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_link.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include +#include + +int run_cnt = 0; + +SEC("perf_event") +int handler(struct pt_regs *ctx) +{ + __sync_fetch_and_add(&run_cnt, 1); + return 0; +} + +char _license[] SEC("license") = "GPL";