diff options
Diffstat (limited to 'tools/perf/util/bpf-event.c')
| -rw-r--r-- | tools/perf/util/bpf-event.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c new file mode 100644 index 000000000000..028c8ec1f62a --- /dev/null +++ b/tools/perf/util/bpf-event.c @@ -0,0 +1,263 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <errno.h> +#include <stdlib.h> +#include <bpf/bpf.h> +#include <bpf/btf.h> +#include <linux/btf.h> +#include "bpf-event.h" +#include "debug.h" +#include "symbol.h" +#include "machine.h" + +#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr)) + +static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len) +{ + int ret = 0; + size_t i; + + for (i = 0; i < len; i++) + ret += snprintf(buf + ret, size - ret, "%02x", data[i]); + return ret; +} + +int machine__process_bpf_event(struct machine *machine __maybe_unused, + union perf_event *event, + struct perf_sample *sample __maybe_unused) +{ + if (dump_trace) + perf_event__fprintf_bpf_event(event, stdout); + return 0; +} + +/* + * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf + * program. One PERF_RECORD_BPF_EVENT is generated for the program. And + * one PERF_RECORD_KSYMBOL is generated for each sub program. + * + * Returns: + * 0 for success; + * -1 for failures; + * -2 for lack of kernel support. + */ +static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool, + perf_event__handler_t process, + struct machine *machine, + int fd, + union perf_event *event, + struct record_opts *opts) +{ + struct ksymbol_event *ksymbol_event = &event->ksymbol_event; + struct bpf_event *bpf_event = &event->bpf_event; + u32 sub_prog_cnt, i, func_info_rec_size = 0; + u8 (*prog_tags)[BPF_TAG_SIZE] = NULL; + struct bpf_prog_info info = { .type = 0, }; + u32 info_len = sizeof(info); + void *func_infos = NULL; + u64 *prog_addrs = NULL; + struct btf *btf = NULL; + u32 *prog_lens = NULL; + bool has_btf = false; + char errbuf[512]; + int err = 0; + + /* Call bpf_obj_get_info_by_fd() to get sizes of arrays */ + err = bpf_obj_get_info_by_fd(fd, &info, &info_len); + + if (err) { + pr_debug("%s: failed to get BPF program info: %s, aborting\n", + __func__, str_error_r(errno, errbuf, sizeof(errbuf))); + return -1; + } + if (info_len < offsetof(struct bpf_prog_info, prog_tags)) { + pr_debug("%s: the kernel is too old, aborting\n", __func__); + return -2; + } + + /* number of ksyms, func_lengths, and tags should match */ + sub_prog_cnt = info.nr_jited_ksyms; + if (sub_prog_cnt != info.nr_prog_tags || + sub_prog_cnt != info.nr_jited_func_lens) + return -1; + + /* check BTF func info support */ + if (info.btf_id && info.nr_func_info && info.func_info_rec_size) { + /* btf func info number should be same as sub_prog_cnt */ + if (sub_prog_cnt != info.nr_func_info) { + pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__); + return -1; + } + if (btf__get_from_id(info.btf_id, &btf)) { + pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info.btf_id); + return -1; + } + func_info_rec_size = info.func_info_rec_size; + func_infos = calloc(sub_prog_cnt, func_info_rec_size); + if (!func_infos) { + pr_debug("%s: failed to allocate memory for func_infos, aborting\n", __func__); + return -1; + } + has_btf = true; + } + + /* + * We need address, length, and tag for each sub program. + * Allocate memory and call bpf_obj_get_info_by_fd() again + */ + prog_addrs = calloc(sub_prog_cnt, sizeof(u64)); + if (!prog_addrs) { + pr_debug("%s: failed to allocate memory for prog_addrs, aborting\n", __func__); + goto out; + } + prog_lens = calloc(sub_prog_cnt, sizeof(u32)); + if (!prog_lens) { + pr_debug("%s: failed to allocate memory for prog_lens, aborting\n", __func__); + goto out; + } + prog_tags = calloc(sub_prog_cnt, BPF_TAG_SIZE); + if (!prog_tags) { + pr_debug("%s: failed to allocate memory for prog_tags, aborting\n", __func__); + goto out; + } + + memset(&info, 0, sizeof(info)); + info.nr_jited_ksyms = sub_prog_cnt; + info.nr_jited_func_lens = sub_prog_cnt; + info.nr_prog_tags = sub_prog_cnt; + info.jited_ksyms = ptr_to_u64(prog_addrs); + info.jited_func_lens = ptr_to_u64(prog_lens); + info.prog_tags = ptr_to_u64(prog_tags); + info_len = sizeof(info); + if (has_btf) { + info.nr_func_info = sub_prog_cnt; + info.func_info_rec_size = func_info_rec_size; + info.func_info = ptr_to_u64(func_infos); + } + + err = bpf_obj_get_info_by_fd(fd, &info, &info_len); + if (err) { + pr_debug("%s: failed to get BPF program info, aborting\n", __func__); + goto out; + } + + /* Synthesize PERF_RECORD_KSYMBOL */ + for (i = 0; i < sub_prog_cnt; i++) { + const struct bpf_func_info *finfo; + const char *short_name = NULL; + const struct btf_type *t; + int name_len; + + *ksymbol_event = (struct ksymbol_event){ + .header = { + .type = PERF_RECORD_KSYMBOL, + .size = offsetof(struct ksymbol_event, name), + }, + .addr = prog_addrs[i], + .len = prog_lens[i], + .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF, + .flags = 0, + }; + name_len = snprintf(ksymbol_event->name, KSYM_NAME_LEN, + "bpf_prog_"); + name_len += snprintf_hex(ksymbol_event->name + name_len, + KSYM_NAME_LEN - name_len, + prog_tags[i], BPF_TAG_SIZE); + if (has_btf) { + finfo = func_infos + i * info.func_info_rec_size; + t = btf__type_by_id(btf, finfo->type_id); + short_name = btf__name_by_offset(btf, t->name_off); + } else if (i == 0 && sub_prog_cnt == 1) { + /* no subprog */ + if (info.name[0]) + short_name = info.name; + } else + short_name = "F"; + if (short_name) + name_len += snprintf(ksymbol_event->name + name_len, + KSYM_NAME_LEN - name_len, + "_%s", short_name); + + ksymbol_event->header.size += PERF_ALIGN(name_len + 1, + sizeof(u64)); + + memset((void *)event + event->header.size, 0, machine->id_hdr_size); + event->header.size += machine->id_hdr_size; + err = perf_tool__process_synth_event(tool, event, + machine, process); + } + + /* Synthesize PERF_RECORD_BPF_EVENT */ + if (opts->bpf_event) { + *bpf_event = (struct bpf_event){ + .header = { + .type = PERF_RECORD_BPF_EVENT, + .size = sizeof(struct bpf_event), + }, + .type = PERF_BPF_EVENT_PROG_LOAD, + .flags = 0, + .id = info.id, + }; + memcpy(bpf_event->tag, prog_tags[i], BPF_TAG_SIZE); + memset((void *)event + event->header.size, 0, machine->id_hdr_size); + event->header.size += machine->id_hdr_size; + err = perf_tool__process_synth_event(tool, event, + machine, process); + } + +out: + free(prog_tags); + free(prog_lens); + free(prog_addrs); + free(func_infos); + free(btf); + return err ? -1 : 0; +} + +int perf_event__synthesize_bpf_events(struct perf_tool *tool, + perf_event__handler_t process, + struct machine *machine, + struct record_opts *opts) +{ + union perf_event *event; + __u32 id = 0; + int err; + int fd; + + event = malloc(sizeof(event->bpf_event) + KSYM_NAME_LEN + machine->id_hdr_size); + if (!event) + return -1; + while (true) { + err = bpf_prog_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + pr_debug("%s: can't get next program: %s%s\n", + __func__, strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + /* don't report error on old kernel or EPERM */ + err = (errno == EINVAL || errno == EPERM) ? 0 : -1; + break; + } + fd = bpf_prog_get_fd_by_id(id); + if (fd < 0) { + pr_debug("%s: failed to get fd for prog_id %u\n", + __func__, id); + continue; + } + + err = perf_event__synthesize_one_bpf_prog(tool, process, + machine, fd, + event, opts); + close(fd); + if (err) { + /* do not return error for old kernel */ + if (err == -2) + err = 0; + break; + } + } + free(event); + return err; +} |