tools/perf/util/bpf-event.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <errno.h>
 #include <stdlib.h>
 #include <bpf/bpf.h>
 #include <bpf/btf.h>
 #include <bpf/libbpf.h>
 #include <linux/btf.h>
 #include <linux/err.h>
 #include <linux/string.h>
 #include <internal/lib.h>
 #include <symbol/kallsyms.h>
 #include "bpf-event.h"
 #include "debug.h"
 #include "dso.h"
 #include "symbol.h"
 #include "machine.h"
 #include "env.h"
 #include "session.h"
 #include "map.h"
 #include "evlist.h"
 #include "record.h"
 #include "util/synthetic-events.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;
 }

 static int machine__process_bpf_event_load(struct machine *machine,
 					   union perf_event *event,
 					   struct perf_sample *sample __maybe_unused)
 {
 	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_info_node *info_node;
 	struct perf_env *env = machine->env;
 	int id = event->bpf.id;
 	unsigned int i;

 	/* perf-record, no need to handle bpf-event */
 	if (env == NULL)
 		return 0;

 	info_node = perf_env__find_bpf_prog_info(env, id);
 	if (!info_node)
 		return 0;
 	info_linear = info_node->info_linear;

 	for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
 		u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
 		u64 addr = addrs[i];
 		struct map *map = maps__find(&machine->kmaps, addr);

 		if (map) {
 			map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
 			map->dso->bpf_prog.id = id;
 			map->dso->bpf_prog.sub_id = i;
 			map->dso->bpf_prog.env = env;
 		}
 	}
 	return 0;
 }

 int machine__process_bpf(struct machine *machine, union perf_event *event,
 			 struct perf_sample *sample)
 {
 	if (dump_trace)
 		perf_event__fprintf_bpf(event, stdout);

 	switch (event->bpf.type) {
 	case PERF_BPF_EVENT_PROG_LOAD:
 		return machine__process_bpf_event_load(machine, event, sample);

 	case PERF_BPF_EVENT_PROG_UNLOAD:
 		/*
 		 * Do not free bpf_prog_info and btf of the program here,
 		 * as annotation still need them. They will be freed at
 		 * the end of the session.
 		 */
 		break;
 	default:
 		pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 		break;
 	}
 	return 0;
 }

 static int perf_env__fetch_btf(struct perf_env *env,
 			       u32 btf_id,
 			       struct btf *btf)
 {
 	struct btf_node *node;
 	u32 data_size;
 	const void *data;

 	data = btf__get_raw_data(btf, &data_size);

 	node = malloc(data_size + sizeof(struct btf_node));
 	if (!node)
 		return -1;

 	node->id = btf_id;
 	node->data_size = data_size;
 	memcpy(node->data, data, data_size);

 	perf_env__insert_btf(env, node);
 	return 0;
 }

 static int synthesize_bpf_prog_name(char *buf, int size,
 				    struct bpf_prog_info *info,
 				    struct btf *btf,
 				    u32 sub_id)
 {
 	u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 	void *func_infos = (void *)(uintptr_t)(info->func_info);
 	u32 sub_prog_cnt = info->nr_jited_ksyms;
 	const struct bpf_func_info *finfo;
 	const char *short_name = NULL;
 	const struct btf_type *t;
 	int name_len;

 	name_len = snprintf(buf, size, "bpf_prog_");
 	name_len += snprintf_hex(buf + name_len, size - name_len,
 				 prog_tags[sub_id], BPF_TAG_SIZE);
 	if (btf) {
 		finfo = func_infos + sub_id * 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 (sub_id == 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(buf + name_len, size - name_len,
 				     "_%s", short_name);
 	return name_len;
 }

 /*
  * 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_session *session,
 					       perf_event__handler_t process,
 					       struct machine *machine,
 					       int fd,
 					       union perf_event *event,
 					       struct record_opts *opts)
 {
 	struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 	struct perf_record_bpf_event *bpf_event = &event->bpf;
 	struct bpf_prog_info_linear *info_linear;
 	struct perf_tool *tool = session->tool;
 	struct bpf_prog_info_node *info_node;
 	struct bpf_prog_info *info;
 	struct btf *btf = NULL;
 	struct perf_env *env;
 	u32 sub_prog_cnt, i;
 	int err = 0;
 	u64 arrays;

 	/*
 	 * for perf-record and perf-report use header.env;
 	 * otherwise, use global perf_env.
 	 */
 	env = session->data ? &session->header.env : &perf_env;

 	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

 	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 	if (IS_ERR_OR_NULL(info_linear)) {
 		info_linear = NULL;
 		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 		return -1;
 	}

 	if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 		pr_debug("%s: the kernel is too old, aborting\n", __func__);
 		return -2;
 	}

 	info = &info_linear->info;

 	/* 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__);
 			err = -1;
 			goto out;
 		}
 		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);
 			err = -1;
 			btf = NULL;
 			goto out;
 		}
 		perf_env__fetch_btf(env, info->btf_id, btf);
 	}

 	/* Synthesize PERF_RECORD_KSYMBOL */
 	for (i = 0; i < sub_prog_cnt; i++) {
 		__u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 		__u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 		int name_len;

 		*ksymbol_event = (struct perf_record_ksymbol) {
 			.header = {
 				.type = PERF_RECORD_KSYMBOL,
 				.size = offsetof(struct perf_record_ksymbol, name),
 			},
 			.addr = prog_addrs[i],
 			.len = prog_lens[i],
 			.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 			.flags = 0,
 		};

 		name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 						    KSYM_NAME_LEN, info, btf, i);
 		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);
 	}

 	if (!opts->no_bpf_event) {
 		/* Synthesize PERF_RECORD_BPF_EVENT */
 		*bpf_event = (struct perf_record_bpf_event) {
 			.header = {
 				.type = PERF_RECORD_BPF_EVENT,
 				.size = sizeof(struct perf_record_bpf_event),
 			},
 			.type = PERF_BPF_EVENT_PROG_LOAD,
 			.flags = 0,
 			.id = info->id,
 		};
 		memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 		memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 		event->header.size += machine->id_hdr_size;

 		/* save bpf_prog_info to env */
 		info_node = malloc(sizeof(struct bpf_prog_info_node));
 		if (!info_node) {
 			err = -1;
 			goto out;
 		}

 		info_node->info_linear = info_linear;
 		perf_env__insert_bpf_prog_info(env, info_node);
 		info_linear = NULL;

 		/*
 		 * process after saving bpf_prog_info to env, so that
 		 * required information is ready for look up
 		 */
 		err = perf_tool__process_synth_event(tool, event,
 						     machine, process);
 	}

 out:
 	free(info_linear);
 	free(btf);
 	return err ? -1 : 0;
 }

 struct kallsyms_parse {
 	union perf_event	*event;
 	perf_event__handler_t	 process;
 	struct machine		*machine;
 	struct perf_tool	*tool;
 };

 static int
 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 {
 	struct machine *machine = data->machine;
 	union perf_event *event = data->event;
 	struct perf_record_ksymbol *ksymbol;
 	int len;

 	ksymbol = &event->ksymbol;

 	*ksymbol = (struct perf_record_ksymbol) {
 		.header = {
 			.type = PERF_RECORD_KSYMBOL,
 			.size = offsetof(struct perf_record_ksymbol, name),
 		},
 		.addr      = addr,
 		.len       = page_size,
 		.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 		.flags     = 0,
 	};

 	len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 	ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 	memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 	event->header.size += machine->id_hdr_size;

 	return perf_tool__process_synth_event(data->tool, event, machine,
 					      data->process);
 }

 static int
 kallsyms_process_symbol(void *data, const char *_name,
 			char type __maybe_unused, u64 start)
 {
 	char disp[KSYM_NAME_LEN];
 	char *module, *name;
 	unsigned long id;
 	int err = 0;

 	module = strchr(_name, '\t');
 	if (!module)
 		return 0;

 	/* We are going after [bpf] module ... */
 	if (strcmp(module + 1, "[bpf]"))
 		return 0;

 	name = memdup(_name, (module - _name) + 1);
 	if (!name)
 		return -ENOMEM;

 	name[module - _name] = 0;

 	/* .. and only for trampolines and dispatchers */
 	if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 	    (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 		err = process_bpf_image(name, start, data);

 	free(name);
 	return err;
 }

 int perf_event__synthesize_bpf_events(struct perf_session *session,
 				      perf_event__handler_t process,
 				      struct machine *machine,
 				      struct record_opts *opts)
 {
 	const char *kallsyms_filename = "/proc/kallsyms";
 	struct kallsyms_parse arg;
 	union perf_event *event;
 	__u32 id = 0;
 	int err;
 	int fd;

 	event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 	if (!event)
 		return -1;

 	/* Synthesize all the bpf programs in system. */
 	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(session, process,
 							  machine, fd,
 							  event, opts);
 		close(fd);
 		if (err) {
 			/* do not return error for old kernel */
 			if (err == -2)
 				err = 0;
 			break;
 		}
 	}

 	/* Synthesize all the bpf images - trampolines/dispatchers. */
 	if (symbol_conf.kallsyms_name != NULL)
 		kallsyms_filename = symbol_conf.kallsyms_name;

 	arg = (struct kallsyms_parse) {
 		.event   = event,
 		.process = process,
 		.machine = machine,
 		.tool    = session->tool,
 	};

 	if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 		pr_err("%s: failed to synthesize bpf images: %s\n",
 		       __func__, strerror(errno));
 	}

 	free(event);
 	return err;
 }

 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 {
 	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_info_node *info_node;
 	struct btf *btf = NULL;
 	u64 arrays;
 	u32 btf_id;
 	int fd;

 	fd = bpf_prog_get_fd_by_id(id);
 	if (fd < 0)
 		return;

 	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
 	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
 	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
 	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
 	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

 	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
 	if (IS_ERR_OR_NULL(info_linear)) {
 		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 		goto out;
 	}

 	btf_id = info_linear->info.btf_id;

 	info_node = malloc(sizeof(struct bpf_prog_info_node));
 	if (info_node) {
 		info_node->info_linear = info_linear;
 		perf_env__insert_bpf_prog_info(env, info_node);
 	} else
 		free(info_linear);

 	if (btf_id == 0)
 		goto out;

 	if (btf__get_from_id(btf_id, &btf)) {
 		pr_debug("%s: failed to get BTF of id %u, aborting\n",
 			 __func__, btf_id);
 		goto out;
 	}
 	perf_env__fetch_btf(env, btf_id, btf);

 out:
 	free(btf);
 	close(fd);
 }

 static int bpf_event__sb_cb(union perf_event *event, void *data)
 {
 	struct perf_env *env = data;

 	if (event->header.type != PERF_RECORD_BPF_EVENT)
 		return -1;

 	switch (event->bpf.type) {
 	case PERF_BPF_EVENT_PROG_LOAD:
 		perf_env__add_bpf_info(env, event->bpf.id);

 	case PERF_BPF_EVENT_PROG_UNLOAD:
 		/*
 		 * Do not free bpf_prog_info and btf of the program here,
 		 * as annotation still need them. They will be freed at
 		 * the end of the session.
 		 */
 		break;
 	default:
 		pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 		break;
 	}

 	return 0;
 }

 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 {
 	struct perf_event_attr attr = {
 		.type	          = PERF_TYPE_SOFTWARE,
 		.config           = PERF_COUNT_SW_DUMMY,
 		.sample_id_all    = 1,
 		.watermark        = 1,
 		.bpf_event        = 1,
 		.size	   = sizeof(attr), /* to capture ABI version */
 	};

 	/*
 	 * Older gcc versions don't support designated initializers, like above,
 	 * for unnamed union members, such as the following:
 	 */
 	attr.wakeup_watermark = 1;

 	return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 }

 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 				    struct perf_env *env,
 				    FILE *fp)
 {
 	__u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 	__u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 	char name[KSYM_NAME_LEN];
 	struct btf *btf = NULL;
 	u32 sub_prog_cnt, i;

 	sub_prog_cnt = info->nr_jited_ksyms;
 	if (sub_prog_cnt != info->nr_prog_tags ||
 	    sub_prog_cnt != info->nr_jited_func_lens)
 		return;

 	if (info->btf_id) {
 		struct btf_node *node;

 		node = perf_env__find_btf(env, info->btf_id);
 		if (node)
 			btf = btf__new((__u8 *)(node->data),
 				       node->data_size);
 	}

 	if (sub_prog_cnt == 1) {
 		synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 		fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 			info->id, name, prog_addrs[0], prog_lens[0]);
 		return;
 	}

 	fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 	for (i = 0; i < sub_prog_cnt; i++) {
 		synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);

 		fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 			i, name, prog_addrs[i], prog_lens[i]);
 	}
 }
	// SPDX-License-Identifier: GPL-2.0
	#include <errno.h>
	#include <stdlib.h>
	#include <bpf/bpf.h>
	#include <bpf/btf.h>
	#include <bpf/libbpf.h>
	#include <linux/btf.h>
	#include <linux/err.h>
	#include <linux/string.h>
	#include <internal/lib.h>
	#include <symbol/kallsyms.h>
	#include "bpf-event.h"
	#include "debug.h"
	#include "dso.h"
	#include "symbol.h"
	#include "machine.h"
	#include "env.h"
	#include "session.h"
	#include "map.h"
	#include "evlist.h"
	#include "record.h"
	#include "util/synthetic-events.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;
	}

	static int machine__process_bpf_event_load(struct machine *machine,
	union perf_event *event,
	struct perf_sample *sample __maybe_unused)
	{
	struct bpf_prog_info_linear *info_linear;
	struct bpf_prog_info_node *info_node;
	struct perf_env *env = machine->env;
	int id = event->bpf.id;
	unsigned int i;

	/* perf-record, no need to handle bpf-event */
	if (env == NULL)
	return 0;

	info_node = perf_env__find_bpf_prog_info(env, id);
	if (!info_node)
	return 0;
	info_linear = info_node->info_linear;

	for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
	u64 addrs = (u64 )(uintptr_t)(info_linear->info.jited_ksyms);
	u64 addr = addrs[i];
	struct map *map = maps__find(&machine->kmaps, addr);

	if (map) {
	map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
	map->dso->bpf_prog.id = id;
	map->dso->bpf_prog.sub_id = i;
	map->dso->bpf_prog.env = env;
	}
	}
	return 0;
	}

	int machine__process_bpf(struct machine machine, union perf_event event,
	struct perf_sample *sample)
	{
	if (dump_trace)
	perf_event__fprintf_bpf(event, stdout);

	switch (event->bpf.type) {
	case PERF_BPF_EVENT_PROG_LOAD:
	return machine__process_bpf_event_load(machine, event, sample);

	case PERF_BPF_EVENT_PROG_UNLOAD:
	/*
	* Do not free bpf_prog_info and btf of the program here,
	* as annotation still need them. They will be freed at
	* the end of the session.
	*/
	break;
	default:
	pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
	break;
	}
	return 0;
	}

	static int perf_env__fetch_btf(struct perf_env *env,
	u32 btf_id,
	struct btf *btf)
	{
	struct btf_node *node;
	u32 data_size;
	const void *data;

	data = btf__get_raw_data(btf, &data_size);

	node = malloc(data_size + sizeof(struct btf_node));
	if (!node)
	return -1;

	node->id = btf_id;
	node->data_size = data_size;
	memcpy(node->data, data, data_size);

	perf_env__insert_btf(env, node);
	return 0;
	}

	static int synthesize_bpf_prog_name(char *buf, int size,
	struct bpf_prog_info *info,
	struct btf *btf,
	u32 sub_id)
	{
	u8 (prog_tags)[BPF_TAG_SIZE] = (void )(uintptr_t)(info->prog_tags);
	void func_infos = (void )(uintptr_t)(info->func_info);
	u32 sub_prog_cnt = info->nr_jited_ksyms;
	const struct bpf_func_info *finfo;
	const char *short_name = NULL;
	const struct btf_type *t;
	int name_len;

	name_len = snprintf(buf, size, "bpf_prog_");
	name_len += snprintf_hex(buf + name_len, size - name_len,
	prog_tags[sub_id], BPF_TAG_SIZE);
	if (btf) {
	finfo = func_infos + sub_id * 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 (sub_id == 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(buf + name_len, size - name_len,
	"_%s", short_name);
	return name_len;
	}

	/*
	* 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_session *session,
	perf_event__handler_t process,
	struct machine *machine,
	int fd,
	union perf_event *event,
	struct record_opts *opts)
	{
	struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
	struct perf_record_bpf_event *bpf_event = &event->bpf;
	struct bpf_prog_info_linear *info_linear;
	struct perf_tool *tool = session->tool;
	struct bpf_prog_info_node *info_node;
	struct bpf_prog_info *info;
	struct btf *btf = NULL;
	struct perf_env *env;
	u32 sub_prog_cnt, i;
	int err = 0;
	u64 arrays;

	/*
	* for perf-record and perf-report use header.env;
	* otherwise, use global perf_env.
	*/
	env = session->data ? &session->header.env : &perf_env;

	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
	arrays \|= 1UL << BPF_PROG_INFO_FUNC_INFO;
	arrays \|= 1UL << BPF_PROG_INFO_PROG_TAGS;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_INSNS;
	arrays \|= 1UL << BPF_PROG_INFO_LINE_INFO;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
	if (IS_ERR_OR_NULL(info_linear)) {
	info_linear = NULL;
	pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
	return -1;
	}

	if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
	pr_debug("%s: the kernel is too old, aborting\n", __func__);
	return -2;
	}

	info = &info_linear->info;

	/* 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__);
	err = -1;
	goto out;
	}
	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);
	err = -1;
	btf = NULL;
	goto out;
	}
	perf_env__fetch_btf(env, info->btf_id, btf);
	}

	/* Synthesize PERF_RECORD_KSYMBOL */
	for (i = 0; i < sub_prog_cnt; i++) {
	__u32 prog_lens = (__u32 )(uintptr_t)(info->jited_func_lens);
	__u64 prog_addrs = (__u64 )(uintptr_t)(info->jited_ksyms);
	int name_len;

	*ksymbol_event = (struct perf_record_ksymbol) {
	.header = {
	.type = PERF_RECORD_KSYMBOL,
	.size = offsetof(struct perf_record_ksymbol, name),
	},
	.addr = prog_addrs[i],
	.len = prog_lens[i],
	.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
	.flags = 0,
	};

	name_len = synthesize_bpf_prog_name(ksymbol_event->name,
	KSYM_NAME_LEN, info, btf, i);
	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);
	}

	if (!opts->no_bpf_event) {
	/* Synthesize PERF_RECORD_BPF_EVENT */
	*bpf_event = (struct perf_record_bpf_event) {
	.header = {
	.type = PERF_RECORD_BPF_EVENT,
	.size = sizeof(struct perf_record_bpf_event),
	},
	.type = PERF_BPF_EVENT_PROG_LOAD,
	.flags = 0,
	.id = info->id,
	};
	memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
	memset((void *)event + event->header.size, 0, machine->id_hdr_size);
	event->header.size += machine->id_hdr_size;

	/* save bpf_prog_info to env */
	info_node = malloc(sizeof(struct bpf_prog_info_node));
	if (!info_node) {
	err = -1;
	goto out;
	}

	info_node->info_linear = info_linear;
	perf_env__insert_bpf_prog_info(env, info_node);
	info_linear = NULL;

	/*
	* process after saving bpf_prog_info to env, so that
	* required information is ready for look up
	*/
	err = perf_tool__process_synth_event(tool, event,
	machine, process);
	}

	out:
	free(info_linear);
	free(btf);
	return err ? -1 : 0;
	}

	struct kallsyms_parse {
	union perf_event *event;
	perf_event__handler_t process;
	struct machine *machine;
	struct perf_tool *tool;
	};

	static int
	process_bpf_image(char name, u64 addr, struct kallsyms_parse data)
	{
	struct machine *machine = data->machine;
	union perf_event *event = data->event;
	struct perf_record_ksymbol *ksymbol;
	int len;

	ksymbol = &event->ksymbol;

	*ksymbol = (struct perf_record_ksymbol) {
	.header = {
	.type = PERF_RECORD_KSYMBOL,
	.size = offsetof(struct perf_record_ksymbol, name),
	},
	.addr = addr,
	.len = page_size,
	.ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
	.flags = 0,
	};

	len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
	ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
	memset((void *) event + event->header.size, 0, machine->id_hdr_size);
	event->header.size += machine->id_hdr_size;

	return perf_tool__process_synth_event(data->tool, event, machine,
	data->process);
	}

	static int
	kallsyms_process_symbol(void data, const char _name,
	char type __maybe_unused, u64 start)
	{
	char disp[KSYM_NAME_LEN];
	char module, name;
	unsigned long id;
	int err = 0;

	module = strchr(_name, '\t');
	if (!module)
	return 0;

	/* We are going after [bpf] module ... */
	if (strcmp(module + 1, "[bpf]"))
	return 0;

	name = memdup(_name, (module - _name) + 1);
	if (!name)
	return -ENOMEM;

	name[module - _name] = 0;

	/* .. and only for trampolines and dispatchers */
	if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) \|\|
	(sscanf(name, "bpf_dispatcher_%s", disp) == 1))
	err = process_bpf_image(name, start, data);

	free(name);
	return err;
	}

	int perf_event__synthesize_bpf_events(struct perf_session *session,
	perf_event__handler_t process,
	struct machine *machine,
	struct record_opts *opts)
	{
	const char *kallsyms_filename = "/proc/kallsyms";
	struct kallsyms_parse arg;
	union perf_event *event;
	__u32 id = 0;
	int err;
	int fd;

	event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
	if (!event)
	return -1;

	/* Synthesize all the bpf programs in system. */
	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(session, process,
	machine, fd,
	event, opts);
	close(fd);
	if (err) {
	/* do not return error for old kernel */
	if (err == -2)
	err = 0;
	break;
	}
	}

	/* Synthesize all the bpf images - trampolines/dispatchers. */
	if (symbol_conf.kallsyms_name != NULL)
	kallsyms_filename = symbol_conf.kallsyms_name;

	arg = (struct kallsyms_parse) {
	.event = event,
	.process = process,
	.machine = machine,
	.tool = session->tool,
	};

	if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
	pr_err("%s: failed to synthesize bpf images: %s\n",
	__func__, strerror(errno));
	}

	free(event);
	return err;
	}

	static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
	{
	struct bpf_prog_info_linear *info_linear;
	struct bpf_prog_info_node *info_node;
	struct btf *btf = NULL;
	u64 arrays;
	u32 btf_id;
	int fd;

	fd = bpf_prog_get_fd_by_id(id);
	if (fd < 0)
	return;

	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
	arrays \|= 1UL << BPF_PROG_INFO_FUNC_INFO;
	arrays \|= 1UL << BPF_PROG_INFO_PROG_TAGS;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_INSNS;
	arrays \|= 1UL << BPF_PROG_INFO_LINE_INFO;
	arrays \|= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
	if (IS_ERR_OR_NULL(info_linear)) {
	pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
	goto out;
	}

	btf_id = info_linear->info.btf_id;

	info_node = malloc(sizeof(struct bpf_prog_info_node));
	if (info_node) {
	info_node->info_linear = info_linear;
	perf_env__insert_bpf_prog_info(env, info_node);
	} else
	free(info_linear);

	if (btf_id == 0)
	goto out;

	if (btf__get_from_id(btf_id, &btf)) {
	pr_debug("%s: failed to get BTF of id %u, aborting\n",
	__func__, btf_id);
	goto out;
	}
	perf_env__fetch_btf(env, btf_id, btf);

	out:
	free(btf);
	close(fd);
	}

	static int bpf_event__sb_cb(union perf_event event, void data)
	{
	struct perf_env *env = data;

	if (event->header.type != PERF_RECORD_BPF_EVENT)
	return -1;

	switch (event->bpf.type) {
	case PERF_BPF_EVENT_PROG_LOAD:
	perf_env__add_bpf_info(env, event->bpf.id);

	case PERF_BPF_EVENT_PROG_UNLOAD:
	/*
	* Do not free bpf_prog_info and btf of the program here,
	* as annotation still need them. They will be freed at
	* the end of the session.
	*/
	break;
	default:
	pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
	break;
	}

	return 0;
	}

	int evlist__add_bpf_sb_event(struct evlist evlist, struct perf_env env)
	{
	struct perf_event_attr attr = {
	.type = PERF_TYPE_SOFTWARE,
	.config = PERF_COUNT_SW_DUMMY,
	.sample_id_all = 1,
	.watermark = 1,
	.bpf_event = 1,
	.size = sizeof(attr), /* to capture ABI version */
	};

	/*
	* Older gcc versions don't support designated initializers, like above,
	* for unnamed union members, such as the following:
	*/
	attr.wakeup_watermark = 1;

	return perf_evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
	}

	void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
	struct perf_env *env,
	FILE *fp)
	{
	__u32 prog_lens = (__u32 )(uintptr_t)(info->jited_func_lens);
	__u64 prog_addrs = (__u64 )(uintptr_t)(info->jited_ksyms);
	char name[KSYM_NAME_LEN];
	struct btf *btf = NULL;
	u32 sub_prog_cnt, i;

	sub_prog_cnt = info->nr_jited_ksyms;
	if (sub_prog_cnt != info->nr_prog_tags \|\|
	sub_prog_cnt != info->nr_jited_func_lens)
	return;

	if (info->btf_id) {
	struct btf_node *node;

	node = perf_env__find_btf(env, info->btf_id);
	if (node)
	btf = btf__new((__u8 *)(node->data),
	node->data_size);
	}

	if (sub_prog_cnt == 1) {
	synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
	fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
	info->id, name, prog_addrs[0], prog_lens[0]);
	return;
	}

	fprintf(fp, "# bpf_prog_info %u:\n", info->id);
	for (i = 0; i < sub_prog_cnt; i++) {
	synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);

	fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
	i, name, prog_addrs[i], prog_lens[i]);
	}
	}