From d279f1f8c64711ca986c3121c8ec811b892932f0 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 11 Dec 2017 11:39:03 -0800 Subject: [PATCH] bpf/tracing: add a bpf test for new ioctl query interface Added a subtest in test_progs. The tracepoint is sched/sched_switch. Multiple bpf programs are attached to this tracepoint and the query interface is exercised. Signed-off-by: Yonghong Song Acked-by: Alexei Starovoitov Acked-by: Peter Zijlstra (Intel) Signed-off-by: Alexei Starovoitov --- tools/include/uapi/linux/perf_event.h | 22 +++++ tools/testing/selftests/bpf/Makefile | 2 +- tools/testing/selftests/bpf/test_progs.c | 133 ++++++++++++++++++++++++++ tools/testing/selftests/bpf/test_tracepoint.c | 26 +++++ 4 files changed, 182 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/test_tracepoint.c diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h index 362493a..f2c354d 100644 --- a/tools/include/uapi/linux/perf_event.h +++ b/tools/include/uapi/linux/perf_event.h @@ -418,6 +418,27 @@ struct perf_event_attr { __u16 __reserved_2; /* align to __u64 */ }; +/* + * Structure used by below PERF_EVENT_IOC_QUERY_BPF command + * to query bpf programs attached to the same perf tracepoint + * as the given perf event. + */ +struct perf_event_query_bpf { + /* + * The below ids array length + */ + __u32 ids_len; + /* + * Set by the kernel to indicate the number of + * available programs + */ + __u32 prog_cnt; + /* + * User provided buffer to store program ids + */ + __u32 ids[0]; +}; + #define perf_flags(attr) (*(&(attr)->read_format + 1)) /* @@ -433,6 +454,7 @@ struct perf_event_attr { #define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *) #define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32) #define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32) +#define PERF_EVENT_IOC_QUERY_BPF _IOWR('$', 10, struct perf_event_query_bpf *) enum perf_event_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 2c9d8c6..255fb1f 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -17,7 +17,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \ test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \ - sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o + sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o TEST_PROGS := test_kmod.sh test_xdp_redirect.sh test_xdp_meta.sh \ test_offload.py diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 6942753..1d7d214 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -21,8 +21,10 @@ typedef __u16 __sum16; #include #include #include +#include #include +#include #include #include #include @@ -617,6 +619,136 @@ static void test_obj_name(void) } } +static void test_tp_attach_query(void) +{ + const int num_progs = 3; + int i, j, bytes, efd, err, prog_fd[num_progs], pmu_fd[num_progs]; + __u32 duration = 0, info_len, saved_prog_ids[num_progs]; + const char *file = "./test_tracepoint.o"; + struct perf_event_query_bpf *query; + struct perf_event_attr attr = {}; + struct bpf_object *obj[num_progs]; + struct bpf_prog_info prog_info; + char buf[256]; + + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/sched/sched_switch/id"); + efd = open(buf, O_RDONLY, 0); + if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) + return; + bytes = read(efd, buf, sizeof(buf)); + close(efd); + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), + "read", "bytes %d errno %d\n", bytes, errno)) + return; + + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN; + attr.sample_period = 1; + attr.wakeup_events = 1; + + query = malloc(sizeof(*query) + sizeof(__u32) * num_progs); + for (i = 0; i < num_progs; i++) { + err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj[i], + &prog_fd[i]); + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno)) + goto cleanup1; + + bzero(&prog_info, sizeof(prog_info)); + prog_info.jited_prog_len = 0; + prog_info.xlated_prog_len = 0; + prog_info.nr_map_ids = 0; + info_len = sizeof(prog_info); + err = bpf_obj_get_info_by_fd(prog_fd[i], &prog_info, &info_len); + if (CHECK(err, "bpf_obj_get_info_by_fd", "err %d errno %d\n", + err, errno)) + goto cleanup1; + saved_prog_ids[i] = prog_info.id; + + pmu_fd[i] = syscall(__NR_perf_event_open, &attr, -1 /* pid */, + 0 /* cpu 0 */, -1 /* group id */, + 0 /* flags */); + if (CHECK(pmu_fd[i] < 0, "perf_event_open", "err %d errno %d\n", + pmu_fd[i], errno)) + goto cleanup2; + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0); + if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", + err, errno)) + goto cleanup3; + + if (i == 0) { + /* check NULL prog array query */ + query->ids_len = num_progs; + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query); + if (CHECK(err || query->prog_cnt != 0, + "perf_event_ioc_query_bpf", + "err %d errno %d query->prog_cnt %u\n", + err, errno, query->prog_cnt)) + goto cleanup3; + } + + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[i]); + if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", + err, errno)) + goto cleanup3; + + if (i == 1) { + /* try to get # of programs only */ + query->ids_len = 0; + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query); + if (CHECK(err || query->prog_cnt != 2, + "perf_event_ioc_query_bpf", + "err %d errno %d query->prog_cnt %u\n", + err, errno, query->prog_cnt)) + goto cleanup3; + + /* try a few negative tests */ + /* invalid query pointer */ + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, + (struct perf_event_query_bpf *)0x1); + if (CHECK(!err || errno != EFAULT, + "perf_event_ioc_query_bpf", + "err %d errno %d\n", err, errno)) + goto cleanup3; + + /* no enough space */ + query->ids_len = 1; + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query); + if (CHECK(!err || errno != ENOSPC || query->prog_cnt != 2, + "perf_event_ioc_query_bpf", + "err %d errno %d query->prog_cnt %u\n", + err, errno, query->prog_cnt)) + goto cleanup3; + } + + query->ids_len = num_progs; + err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query); + if (CHECK(err || query->prog_cnt != (i + 1), + "perf_event_ioc_query_bpf", + "err %d errno %d query->prog_cnt %u\n", + err, errno, query->prog_cnt)) + goto cleanup3; + for (j = 0; j < i + 1; j++) + if (CHECK(saved_prog_ids[j] != query->ids[j], + "perf_event_ioc_query_bpf", + "#%d saved_prog_id %x query prog_id %x\n", + j, saved_prog_ids[j], query->ids[j])) + goto cleanup3; + } + + i = num_progs - 1; + for (; i >= 0; i--) { + cleanup3: + ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE); + cleanup2: + close(pmu_fd[i]); + cleanup1: + bpf_object__close(obj[i]); + } + free(query); +} + int main(void) { struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY }; @@ -630,6 +762,7 @@ int main(void) test_bpf_obj_id(); test_pkt_md_access(); test_obj_name(); + test_tp_attach_query(); printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt); return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS; diff --git a/tools/testing/selftests/bpf/test_tracepoint.c b/tools/testing/selftests/bpf/test_tracepoint.c new file mode 100644 index 0000000..04bf084 --- /dev/null +++ b/tools/testing/selftests/bpf/test_tracepoint.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2017 Facebook + +#include +#include "bpf_helpers.h" + +/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +struct sched_switch_args { + unsigned long long pad; + char prev_comm[16]; + int prev_pid; + int prev_prio; + long long prev_state; + char next_comm[16]; + int next_pid; + int next_prio; +}; + +SEC("tracepoint/sched/sched_switch") +int oncpu(struct sched_switch_args *ctx) +{ + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */ -- 2.7.4