1 // SPDX-License-Identifier: GPL-2.0
36 	 * 3. map: 1 always, pointer points to additional struct with number
81  * Map of C-string key/value pairs with fixed maximum capacity. Each map has
83  * way appropriate. Map is "write-only", there is no way to get data out of
84  * map. Map is intended to be used to provide metadata for profilers and is
85  * not to be used for internal in-app communication. All methods are
86  * thread-safe.
96 	/* number of used entries in map */
112 #define TLS_NOT_SET -1
124 	 * - -1 (TLS_NOT_SET) - no metavariable;
125 	 * - 0 (TLS_LOCAL_EXEC) - Local Executable mode;
126 	 * - 1 (TLS_IMM_EXEC) - Immediate Executable mode;
127 	 * - 2 (TLS_GENERAL_DYN) - General Dynamic mode;
134 	 * TLS_LOCAL_EXEC: offset from thread pointer (fs:0 for x86-64,
155 	 * cnt <0 - map value isn't set;
156 	 * 0 - map has id set, but no key/value entries
179 	/* if map_descrs[i].cnt == -1, metavar is not present/set */
182 	 * payload has compactly packed values of str and map variables in the
261  * For x86-64, this is mapped onto two entries in GOT.
278 	 * - -1 (TLS_NOT_SET), if no metavar is present;  in calc_location()
279 	 * - 0 (TLS_LOCAL_EXEC), if metavar uses Local Executable mode of TLS  in calc_location()
280 	 * (offset from fs:0 for x86-64 or tpidr_el0 for aarch64);  in calc_location()
281 	 * - 1 (TLS_IMM_EXEC), if metavar uses Immediate Executable mode of TLS;  in calc_location()
282 	 * - 2 (TLS_GENERAL_DYN), if metavar uses General Dynamic mode of TLS;  in calc_location()
285 	 * to get NULL for "no metavar" location, or correct pointer for local  in calc_location()
288 	if (loc->tls_mode <= TLS_LOCAL_EXEC) {  in calc_location()
291 		void *addr = tls_base + loc->offset;  in calc_location()
292 		/* multiply by (tls_mode + 1) to get NULL, if we have no  in calc_location()
294 		return (void *)((loc->tls_mode + 1) * (int64_t)addr);  in calc_location()
300 	 *  - loc->offset is pointing to a GOT entry containing fixed offset  in calc_location()
304 	 *  - loc->offset is pointing to a beginning of double GOT entries;  in calc_location()
305 	 *  - (for aarch64 only) second entry points to tls_index_t struct;  in calc_location()
306 	 *  - (for x86-64 only) two GOT entries are already tls_index_t;  in calc_location()
307 	 *  - tls_index_t->module is used to find start of TLS section in  in calc_location()
309 	 *  - tls_index_t->offset provides offset within that TLS section,  in calc_location()
317 			    (void *)loc->offset);  in calc_location()
320 		/* dtv = ((struct tcbhead *)tls_base)->dtv[tls_index.module] */  in calc_location()
322 				    &((struct tcbhead *)tls_base)->dtv);  in calc_location()
328 	/* if pointer has (void *)-1 value, then TLS wasn't initialized yet */  in calc_location()
329 	return tls_ptr && tls_ptr != (void *)-1  in calc_location()
344 	void *location = calc_location(&cfg->int_locs[idx], tls_base);  in read_int_var()
349 	data->int_vals[idx] = value->val;  in read_int_var()
350 	if (value->header.len)  in read_int_var()
351 		data->int_vals_set_mask |= (1 << idx);  in read_int_var()
363 	data->str_lens[idx] = 0;  in read_str_var()
364 	location = calc_location(&cfg->str_locs[idx], tls_base);  in read_str_var()
369 	len = bpf_probe_read_user_str(payload, STROBE_MAX_STR_LEN, value->ptr);  in read_str_var()
380 	data->str_lens[idx] = len;  in read_str_var()
390 	struct strobe_map_descr* descr = &data->map_descrs[idx];  in read_map_var()
391 	struct strobe_map_raw map;  in read_map_var()  local
396 	descr->tag_len = 0; /* presume no tag is set */  in read_map_var()
397 	descr->cnt = -1; /* presume no value is set */  in read_map_var()
399 	location = calc_location(&cfg->map_locs[idx], tls_base);  in read_map_var()
404 	if (bpf_probe_read_user(&map, sizeof(struct strobe_map_raw), value->ptr))  in read_map_var()
407 	descr->id = map.id;  in read_map_var()
408 	descr->cnt = map.cnt;  in read_map_var()
409 	if (cfg->req_meta_idx == idx) {  in read_map_var()
410 		data->req_id = map.id;  in read_map_var()
411 		data->req_meta_valid = 1;  in read_map_var()
414 	len = bpf_probe_read_user_str(payload, STROBE_MAX_STR_LEN, map.tag);  in read_map_var()
416 		descr->tag_len = len;  in read_map_var()
426 		if (i >= map.cnt)  in read_map_var()
429 		descr->key_lens[i] = 0;  in read_map_var()
431 					      map.entries[i].key);  in read_map_var()
433 			descr->key_lens[i] = len;  in read_map_var()
436 		descr->val_lens[i] = 0;  in read_map_var()
438 					      map.entries[i].val);  in read_map_var()
440 			descr->val_lens[i] = len;  in read_map_var()
449  * read_strobe_meta returns NULL, if no metadata was read; otherwise returns
469 	data->int_vals_set_mask = 0;  in read_strobe_meta()
470 	data->req_meta_valid = 0;  in read_strobe_meta()
471 	payload = data->payload;  in read_strobe_meta()
474 	 * tls_base = (void *)task->thread.fsbase;  in read_strobe_meta()
522 	sample->pid = pid;  in on_event()
523 	bpf_get_current_comm(&sample->comm, TASK_COMM_LEN);  in on_event()
525 	sample->ktime = ktime_ns;  in on_event()
528 	sample_end = read_strobe_meta(task, &sample->metadata);  in on_event()
529 	sample->has_meta = sample_end != NULL;  in on_event()
530 	sample_end = sample_end ? : &sample->metadata;  in on_event()
533 		sample->kernel_stack_id = bpf_get_stackid(ctx, &stacks_1, 0);  in on_event()
534 		sample->user_stack_id = bpf_get_stackid(ctx, &stacks_1, BPF_F_USER_STACK);  in on_event()
536 		sample->kernel_stack_id = bpf_get_stackid(ctx, &stacks_0, 0);  in on_event()
537 		sample->user_stack_id = bpf_get_stackid(ctx, &stacks_0, BPF_F_USER_STACK);  in on_event()
540 	uint64_t sample_size = sample_end - (void *)sample;  in on_event()