diff --git a/include/linux/bpf.h b/include/linux/bpf.h index e55e4255a210..f812ac508e9f 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -254,6 +254,7 @@ typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy); +int bpf_event_query_prog_array(struct perf_event *event, void __user *info); int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr); @@ -285,6 +286,9 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs, struct bpf_prog *old_prog); +int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, + __u32 __user *prog_ids, u32 request_cnt, + __u32 __user *prog_cnt); int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index b9a4953018ed..769533696483 100644 --- a/include/uapi/linux/perf_event.h +++ b/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/kernel/bpf/core.c b/kernel/bpf/core.c index 86b50aa26ee8..b16c6f8f42b6 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1462,6 +1462,8 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, rcu_read_lock(); prog = rcu_dereference(progs)->progs; for (; *prog; prog++) { + if (*prog == &dummy_bpf_prog.prog) + continue; id = (*prog)->aux->id; if (copy_to_user(prog_ids + i, &id, sizeof(id))) { rcu_read_unlock(); @@ -1545,6 +1547,25 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, return 0; } +int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, + __u32 __user *prog_ids, u32 request_cnt, + __u32 __user *prog_cnt) +{ + u32 cnt = 0; + + if (array) + cnt = bpf_prog_array_length(array); + + if (copy_to_user(prog_cnt, &cnt, sizeof(cnt))) + return -EFAULT; + + /* return early if user requested only program count or nothing to copy */ + if (!request_cnt || !cnt) + return 0; + + return bpf_prog_array_copy_to_user(array, prog_ids, request_cnt); +} + static void bpf_prog_free_deferred(struct work_struct *work) { struct bpf_prog_aux *aux; diff --git a/kernel/events/core.c b/kernel/events/core.c index 16beab4767e1..f10609e539d4 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4723,6 +4723,9 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon rcu_read_unlock(); return 0; } + + case PERF_EVENT_IOC_QUERY_BPF: + return bpf_event_query_prog_array(event, (void __user *)arg); default: return -ENOTTY; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 0ce99c379c30..b143f2a05aff 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -820,3 +820,26 @@ void perf_event_detach_bpf_prog(struct perf_event *event) unlock: mutex_unlock(&bpf_event_mutex); } + +int bpf_event_query_prog_array(struct perf_event *event, void __user *info) +{ + struct perf_event_query_bpf __user *uquery = info; + struct perf_event_query_bpf query = {}; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (event->attr.type != PERF_TYPE_TRACEPOINT) + return -EINVAL; + if (copy_from_user(&query, uquery, sizeof(query))) + return -EFAULT; + + mutex_lock(&bpf_event_mutex); + ret = bpf_prog_array_copy_info(event->tp_event->prog_array, + uquery->ids, + query.ids_len, + &uquery->prog_cnt); + mutex_unlock(&bpf_event_mutex); + + return ret; +} diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h index 362493a2f950..f2c354d5f519 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 2c9d8c63c6fa..255fb1f50f6b 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 69427531408d..1d7d2149163a 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 000000000000..04bf084517e0 --- /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 */