| Message ID | 20190116001410.3522226-8-songliubraving@fb.com |
|---|---|
| State | Superseded |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | reveal invisible bpf programs | expand |
Em Tue, Jan 15, 2019 at 04:14:08PM -0800, Song Liu escreveu: > This patch synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for > BPF programs loaded before perf-record. This is achieved by gathering > information about all BPF programs via sys_bpf. > > Signed-off-by: Song Liu <songliubraving@fb.com> > --- > tools/perf/builtin-record.c | 6 ++ > tools/perf/util/bpf-event.c | 206 ++++++++++++++++++++++++++++++++++++ > tools/perf/util/bpf-event.h | 5 + > 3 files changed, 217 insertions(+) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index deaf9b902094..88ea11d57c6f 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -41,6 +41,7 @@ > #include "util/perf-hooks.h" > #include "util/time-utils.h" > #include "util/units.h" > +#include "util/bpf-event.h" > #include "asm/bug.h" > > #include <errno.h> > @@ -1082,6 +1083,11 @@ static int record__synthesize(struct record *rec, bool tail) > return err; > } > > + err = perf_event__synthesize_bpf_events(tool, process_synthesized_event, > + machine, opts); > + if (err < 0) > + pr_warning("Couldn't synthesize bpf events.\n"); > + > err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads, > process_synthesized_event, opts->sample_address, > 1); > diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c > index 87004706874f..4fe30ad622b8 100644 > --- a/tools/perf/util/bpf-event.c > +++ b/tools/perf/util/bpf-event.c > @@ -1,10 +1,24 @@ > // SPDX-License-Identifier: GPL-2.0 > #include <errno.h> > #include <bpf/bpf.h> > +#include <bpf/btf.h> > +#include <linux/btf.h> > #include "bpf-event.h" > #include "debug.h" > #include "symbol.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) > @@ -13,3 +27,195 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused, > 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. > + */ > +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; > + u8 (*prog_tags)[BPF_TAG_SIZE] = NULL; > + struct bpf_prog_info info = {}; > + 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; > + 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 || info_len < 192 /* need field prog_tags */) > + return -1; perhaps: > offsetof(bpf_prog_info, prog_tags) Makes this clearer, i.e. the kernel needs to be providing a struct bpf_prog_info with that field? > + > + /* 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) Can you ad some pr_debug() with some informative message to help with debugging? > + return -1; > + if (btf__get_from_id(info.btf_id, &btf)) Ditto. > + return -1; > + func_info_rec_size = info.func_info_rec_size; > + func_infos = malloc(sub_prog_cnt * func_info_rec_size); > + if (!func_infos) Ditto. > + 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 = (u64 *)malloc(sizeof(u64) * sub_prog_cnt); > + prog_lens = (u32 *)malloc(sizeof(u64) * sub_prog_cnt); Why the casting? And also since its for N elements of a sizeof, why not use calloc(): > + prog_tags = malloc(sizeof(u8) * BPF_TAG_SIZE * sub_prog_cnt); > + > + err = !prog_addrs || !prog_lens || !prog_tags; > + if (err) > + 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) This is all new, its better to have pr_debug() stuff in here to help debugging. > + 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 = sizeof(struct ksymbol_event), > + }, > + .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)); > + 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); > + 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); > + if (!event) > + return -1; > + while (true) { > + err = bpf_prog_get_next_id(id, &id); > + if (err) { > + if (errno == ENOENT) { > + err = 0; > + break; > + } > + pr_err("can't get next program: %s%s", > + strerror(errno), > + errno == EINVAL ? " -- kernel too old?" : ""); > + /* don't report error on old kernel */ > + err = (errno == EINVAL) ? 0 : -1; > + break; > + } > + fd = bpf_prog_get_fd_by_id(id); > + if (fd < 0) { > + pr_debug("Failed to get fd for prog_id %u\n", id); > + continue; > + } > + > + err = perf_event__synthesize_one_bpf_prog( > + tool, process, machine, fd, event, opts); first parameter on the same line of the function call, please. > + close(fd); > + if (err) > + break; > + } > + free(event); > + return err; > +} > diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h > index d5ca355dd298..38aee4040f12 100644 > --- a/tools/perf/util/bpf-event.h > +++ b/tools/perf/util/bpf-event.h > @@ -8,4 +8,9 @@ int machine__process_bpf_event(struct machine *machine, > union perf_event *event, > struct perf_sample *sample); > > +int perf_event__synthesize_bpf_events(struct perf_tool *tool, > + perf_event__handler_t process, > + struct machine *machine, > + struct record_opts *opts); > + > #endif > -- > 2.17.1
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index deaf9b902094..88ea11d57c6f 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -41,6 +41,7 @@ #include "util/perf-hooks.h" #include "util/time-utils.h" #include "util/units.h" +#include "util/bpf-event.h" #include "asm/bug.h" #include <errno.h> @@ -1082,6 +1083,11 @@ static int record__synthesize(struct record *rec, bool tail) return err; } + err = perf_event__synthesize_bpf_events(tool, process_synthesized_event, + machine, opts); + if (err < 0) + pr_warning("Couldn't synthesize bpf events.\n"); + err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads, process_synthesized_event, opts->sample_address, 1); diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c index 87004706874f..4fe30ad622b8 100644 --- a/tools/perf/util/bpf-event.c +++ b/tools/perf/util/bpf-event.c @@ -1,10 +1,24 @@ // SPDX-License-Identifier: GPL-2.0 #include <errno.h> #include <bpf/bpf.h> +#include <bpf/btf.h> +#include <linux/btf.h> #include "bpf-event.h" #include "debug.h" #include "symbol.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) @@ -13,3 +27,195 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused, 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. + */ +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; + u8 (*prog_tags)[BPF_TAG_SIZE] = NULL; + struct bpf_prog_info info = {}; + 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; + 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 || info_len < 192 /* need field prog_tags */) + return -1; + + /* 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) + return -1; + if (btf__get_from_id(info.btf_id, &btf)) + return -1; + func_info_rec_size = info.func_info_rec_size; + func_infos = malloc(sub_prog_cnt * func_info_rec_size); + if (!func_infos) + 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 = (u64 *)malloc(sizeof(u64) * sub_prog_cnt); + prog_lens = (u32 *)malloc(sizeof(u64) * sub_prog_cnt); + prog_tags = malloc(sizeof(u8) * BPF_TAG_SIZE * sub_prog_cnt); + + err = !prog_addrs || !prog_lens || !prog_tags; + if (err) + 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) + 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 = sizeof(struct ksymbol_event), + }, + .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)); + 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); + 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); + if (!event) + return -1; + while (true) { + err = bpf_prog_get_next_id(id, &id); + if (err) { + if (errno == ENOENT) { + err = 0; + break; + } + pr_err("can't get next program: %s%s", + strerror(errno), + errno == EINVAL ? " -- kernel too old?" : ""); + /* don't report error on old kernel */ + err = (errno == EINVAL) ? 0 : -1; + break; + } + fd = bpf_prog_get_fd_by_id(id); + if (fd < 0) { + pr_debug("Failed to get fd for prog_id %u\n", id); + continue; + } + + err = perf_event__synthesize_one_bpf_prog( + tool, process, machine, fd, event, opts); + close(fd); + if (err) + break; + } + free(event); + return err; +} diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h index d5ca355dd298..38aee4040f12 100644 --- a/tools/perf/util/bpf-event.h +++ b/tools/perf/util/bpf-event.h @@ -8,4 +8,9 @@ int machine__process_bpf_event(struct machine *machine, union perf_event *event, struct perf_sample *sample); +int perf_event__synthesize_bpf_events(struct perf_tool *tool, + perf_event__handler_t process, + struct machine *machine, + struct record_opts *opts); + #endif
This patch synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for BPF programs loaded before perf-record. This is achieved by gathering information about all BPF programs via sys_bpf. Signed-off-by: Song Liu <songliubraving@fb.com> --- tools/perf/builtin-record.c | 6 ++ tools/perf/util/bpf-event.c | 206 ++++++++++++++++++++++++++++++++++++ tools/perf/util/bpf-event.h | 5 + 3 files changed, 217 insertions(+)