1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * trace_boot.c 4 * Tracing kernel boot-time 5 */ 6 7 #define pr_fmt(fmt) "trace_boot: " fmt 8 9 #include <linux/bootconfig.h> 10 #include <linux/cpumask.h> 11 #include <linux/ftrace.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/mutex.h> 15 #include <linux/string.h> 16 #include <linux/slab.h> 17 #include <linux/trace.h> 18 #include <linux/trace_events.h> 19 20 #include "trace.h" 21 22 #define MAX_BUF_LEN 256 23 24 static void __init 25 trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node) 26 { 27 struct xbc_node *anode; 28 const char *p; 29 char buf[MAX_BUF_LEN]; 30 unsigned long v = 0; 31 32 /* Common ftrace options */ 33 xbc_node_for_each_array_value(node, "options", anode, p) { 34 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) { 35 pr_err("String is too long: %s\n", p); 36 continue; 37 } 38 39 if (trace_set_options(tr, buf) < 0) 40 pr_err("Failed to set option: %s\n", buf); 41 } 42 43 p = xbc_node_find_value(node, "tracing_on", NULL); 44 if (p && *p != '\0') { 45 if (kstrtoul(p, 10, &v)) 46 pr_err("Failed to set tracing on: %s\n", p); 47 if (v) 48 tracer_tracing_on(tr); 49 else 50 tracer_tracing_off(tr); 51 } 52 53 p = xbc_node_find_value(node, "trace_clock", NULL); 54 if (p && *p != '\0') { 55 if (tracing_set_clock(tr, p) < 0) 56 pr_err("Failed to set trace clock: %s\n", p); 57 } 58 59 p = xbc_node_find_value(node, "buffer_size", NULL); 60 if (p && *p != '\0') { 61 v = memparse(p, NULL); 62 if (v < PAGE_SIZE) 63 pr_err("Buffer size is too small: %s\n", p); 64 if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0) 65 pr_err("Failed to resize trace buffer to %s\n", p); 66 } 67 68 p = xbc_node_find_value(node, "cpumask", NULL); 69 if (p && *p != '\0') { 70 cpumask_var_t new_mask; 71 72 if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) { 73 if (cpumask_parse(p, new_mask) < 0 || 74 tracing_set_cpumask(tr, new_mask) < 0) 75 pr_err("Failed to set new CPU mask %s\n", p); 76 free_cpumask_var(new_mask); 77 } 78 } 79 } 80 81 #ifdef CONFIG_EVENT_TRACING 82 static void __init 83 trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node) 84 { 85 struct xbc_node *anode; 86 char buf[MAX_BUF_LEN]; 87 const char *p; 88 89 xbc_node_for_each_array_value(node, "events", anode, p) { 90 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) { 91 pr_err("String is too long: %s\n", p); 92 continue; 93 } 94 95 if (ftrace_set_clr_event(tr, buf, 1) < 0) 96 pr_err("Failed to enable event: %s\n", p); 97 } 98 } 99 100 #ifdef CONFIG_KPROBE_EVENTS 101 static int __init 102 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event) 103 { 104 struct dynevent_cmd cmd; 105 struct xbc_node *anode; 106 char buf[MAX_BUF_LEN]; 107 const char *val; 108 int ret = 0; 109 110 xbc_node_for_each_array_value(node, "probes", anode, val) { 111 kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); 112 113 ret = kprobe_event_gen_cmd_start(&cmd, event, val); 114 if (ret) { 115 pr_err("Failed to generate probe: %s\n", buf); 116 break; 117 } 118 119 ret = kprobe_event_gen_cmd_end(&cmd); 120 if (ret) { 121 pr_err("Failed to add probe: %s\n", buf); 122 break; 123 } 124 } 125 126 return ret; 127 } 128 #else 129 static inline int __init 130 trace_boot_add_kprobe_event(struct xbc_node *node, const char *event) 131 { 132 pr_err("Kprobe event is not supported.\n"); 133 return -ENOTSUPP; 134 } 135 #endif 136 137 #ifdef CONFIG_SYNTH_EVENTS 138 static int __init 139 trace_boot_add_synth_event(struct xbc_node *node, const char *event) 140 { 141 struct dynevent_cmd cmd; 142 struct xbc_node *anode; 143 char buf[MAX_BUF_LEN]; 144 const char *p; 145 int ret; 146 147 synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN); 148 149 ret = synth_event_gen_cmd_start(&cmd, event, NULL); 150 if (ret) 151 return ret; 152 153 xbc_node_for_each_array_value(node, "fields", anode, p) { 154 ret = synth_event_add_field_str(&cmd, p); 155 if (ret) 156 return ret; 157 } 158 159 ret = synth_event_gen_cmd_end(&cmd); 160 if (ret < 0) 161 pr_err("Failed to add synthetic event: %s\n", buf); 162 163 return ret; 164 } 165 #else 166 static inline int __init 167 trace_boot_add_synth_event(struct xbc_node *node, const char *event) 168 { 169 pr_err("Synthetic event is not supported.\n"); 170 return -ENOTSUPP; 171 } 172 #endif 173 174 #ifdef CONFIG_HIST_TRIGGERS 175 static int __init __printf(3, 4) 176 append_printf(char **bufp, char *end, const char *fmt, ...) 177 { 178 va_list args; 179 int ret; 180 181 if (*bufp == end) 182 return -ENOSPC; 183 184 va_start(args, fmt); 185 ret = vsnprintf(*bufp, end - *bufp, fmt, args); 186 if (ret < end - *bufp) { 187 *bufp += ret; 188 } else { 189 *bufp = end; 190 ret = -ERANGE; 191 } 192 va_end(args); 193 194 return ret; 195 } 196 197 static int __init 198 append_str_nospace(char **bufp, char *end, const char *str) 199 { 200 char *p = *bufp; 201 int len; 202 203 while (p < end - 1 && *str != '\0') { 204 if (!isspace(*str)) 205 *(p++) = *str; 206 str++; 207 } 208 *p = '\0'; 209 if (p == end - 1) { 210 *bufp = end; 211 return -ENOSPC; 212 } 213 len = p - *bufp; 214 *bufp = p; 215 return (int)len; 216 } 217 218 static int __init 219 trace_boot_hist_add_array(struct xbc_node *hnode, char **bufp, 220 char *end, const char *key) 221 { 222 struct xbc_node *knode, *anode; 223 const char *p; 224 char sep; 225 226 knode = xbc_node_find_child(hnode, key); 227 if (knode) { 228 anode = xbc_node_get_child(knode); 229 if (!anode) { 230 pr_err("hist.%s requires value(s).\n", key); 231 return -EINVAL; 232 } 233 234 append_printf(bufp, end, ":%s", key); 235 sep = '='; 236 xbc_array_for_each_value(anode, p) { 237 append_printf(bufp, end, "%c%s", sep, p); 238 if (sep == '=') 239 sep = ','; 240 } 241 } else 242 return -ENOENT; 243 244 return 0; 245 } 246 247 static int __init 248 trace_boot_hist_add_handler(struct xbc_node *hnode, char **bufp, 249 char *end, const char *param) 250 { 251 struct xbc_node *knode, *anode; 252 const char *p; 253 char sep; 254 255 /* Compose 'handler' parameter */ 256 p = xbc_node_find_value(hnode, param, NULL); 257 if (!p) { 258 pr_err("hist.%s requires '%s' option.\n", 259 xbc_node_get_data(hnode), param); 260 return -EINVAL; 261 } 262 append_printf(bufp, end, ":%s(%s)", xbc_node_get_data(hnode), p); 263 264 /* Compose 'action' parameter */ 265 knode = xbc_node_find_child(hnode, "trace"); 266 if (!knode) 267 knode = xbc_node_find_child(hnode, "save"); 268 269 if (knode) { 270 anode = xbc_node_get_child(knode); 271 if (!anode || !xbc_node_is_value(anode)) { 272 pr_err("hist.%s.%s requires value(s).\n", 273 xbc_node_get_data(hnode), 274 xbc_node_get_data(knode)); 275 return -EINVAL; 276 } 277 278 append_printf(bufp, end, ".%s", xbc_node_get_data(knode)); 279 sep = '('; 280 xbc_array_for_each_value(anode, p) { 281 append_printf(bufp, end, "%c%s", sep, p); 282 if (sep == '(') 283 sep = ','; 284 } 285 append_printf(bufp, end, ")"); 286 } else if (xbc_node_find_child(hnode, "snapshot")) { 287 append_printf(bufp, end, ".snapshot()"); 288 } else { 289 pr_err("hist.%s requires an action.\n", 290 xbc_node_get_data(hnode)); 291 return -EINVAL; 292 } 293 294 return 0; 295 } 296 297 /* 298 * Histogram boottime tracing syntax. 299 * 300 * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist { 301 * keys = <KEY>[,...] 302 * values = <VAL>[,...] 303 * sort = <SORT-KEY>[,...] 304 * size = <ENTRIES> 305 * name = <HISTNAME> 306 * var { <VAR> = <EXPR> ... } 307 * pause|continue|clear 308 * onmax|onchange { var = <VAR>; <ACTION> [= <PARAM>] } 309 * onmatch { event = <EVENT>; <ACTION> [= <PARAM>] } 310 * filter = <FILTER> 311 * } 312 * 313 * Where <ACTION> are; 314 * 315 * trace = <EVENT>, <ARG1>[, ...] 316 * save = <ARG1>[, ...] 317 * snapshot 318 */ 319 static int __init 320 trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size) 321 { 322 struct xbc_node *node, *knode; 323 char *end = buf + size; 324 const char *p; 325 int ret = 0; 326 327 append_printf(&buf, end, "hist"); 328 329 ret = trace_boot_hist_add_array(hnode, &buf, end, "keys"); 330 if (ret < 0) { 331 if (ret == -ENOENT) 332 pr_err("hist requires keys.\n"); 333 return -EINVAL; 334 } 335 336 ret = trace_boot_hist_add_array(hnode, &buf, end, "values"); 337 if (ret == -EINVAL) 338 return ret; 339 ret = trace_boot_hist_add_array(hnode, &buf, end, "sort"); 340 if (ret == -EINVAL) 341 return ret; 342 343 p = xbc_node_find_value(hnode, "size", NULL); 344 if (p) 345 append_printf(&buf, end, ":size=%s", p); 346 347 p = xbc_node_find_value(hnode, "name", NULL); 348 if (p) 349 append_printf(&buf, end, ":name=%s", p); 350 351 node = xbc_node_find_child(hnode, "var"); 352 if (node) { 353 xbc_node_for_each_key_value(node, knode, p) { 354 /* Expression must not include spaces. */ 355 append_printf(&buf, end, ":%s=", 356 xbc_node_get_data(knode)); 357 append_str_nospace(&buf, end, p); 358 } 359 } 360 361 /* Histogram control attributes (mutual exclusive) */ 362 if (xbc_node_find_child(hnode, "pause")) 363 append_printf(&buf, end, ":pause"); 364 else if (xbc_node_find_child(hnode, "continue")) 365 append_printf(&buf, end, ":continue"); 366 else if (xbc_node_find_child(hnode, "clear")) 367 append_printf(&buf, end, ":clear"); 368 369 /* Histogram handler and actions */ 370 node = xbc_node_find_child(hnode, "onmax"); 371 if (node && trace_boot_hist_add_handler(node, &buf, end, "var") < 0) 372 return -EINVAL; 373 node = xbc_node_find_child(hnode, "onchange"); 374 if (node && trace_boot_hist_add_handler(node, &buf, end, "var") < 0) 375 return -EINVAL; 376 node = xbc_node_find_child(hnode, "onmatch"); 377 if (node && trace_boot_hist_add_handler(node, &buf, end, "event") < 0) 378 return -EINVAL; 379 380 p = xbc_node_find_value(hnode, "filter", NULL); 381 if (p) 382 append_printf(&buf, end, " if %s", p); 383 384 if (buf == end) { 385 pr_err("hist exceeds the max command length.\n"); 386 return -E2BIG; 387 } 388 389 return 0; 390 } 391 #else 392 static int __init 393 trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size) 394 { 395 return -EOPNOTSUPP; 396 } 397 #endif 398 399 static void __init 400 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode, 401 struct xbc_node *enode) 402 { 403 struct trace_event_file *file; 404 struct xbc_node *anode; 405 char buf[MAX_BUF_LEN]; 406 const char *p, *group, *event; 407 408 group = xbc_node_get_data(gnode); 409 event = xbc_node_get_data(enode); 410 411 if (!strcmp(group, "kprobes")) 412 if (trace_boot_add_kprobe_event(enode, event) < 0) 413 return; 414 if (!strcmp(group, "synthetic")) 415 if (trace_boot_add_synth_event(enode, event) < 0) 416 return; 417 418 mutex_lock(&event_mutex); 419 file = find_event_file(tr, group, event); 420 if (!file) { 421 pr_err("Failed to find event: %s:%s\n", group, event); 422 goto out; 423 } 424 425 p = xbc_node_find_value(enode, "filter", NULL); 426 if (p && *p != '\0') { 427 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) 428 pr_err("filter string is too long: %s\n", p); 429 else if (apply_event_filter(file, buf) < 0) 430 pr_err("Failed to apply filter: %s\n", buf); 431 } 432 433 if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) { 434 xbc_node_for_each_array_value(enode, "actions", anode, p) { 435 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) 436 pr_err("action string is too long: %s\n", p); 437 else if (trigger_process_regex(file, buf) < 0) 438 pr_err("Failed to apply an action: %s\n", buf); 439 } 440 anode = xbc_node_find_child(enode, "hist"); 441 if (anode && 442 trace_boot_compose_hist_cmd(anode, buf, ARRAY_SIZE(buf)) == 0) { 443 if (trigger_process_regex(file, buf) < 0) 444 pr_err("Failed to apply hist trigger: %s\n", buf); 445 } 446 } else if (xbc_node_find_value(enode, "actions", NULL)) 447 pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n"); 448 449 if (xbc_node_find_value(enode, "enable", NULL)) { 450 if (trace_event_enable_disable(file, 1, 0) < 0) 451 pr_err("Failed to enable event node: %s:%s\n", 452 group, event); 453 } 454 out: 455 mutex_unlock(&event_mutex); 456 } 457 458 static void __init 459 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node) 460 { 461 struct xbc_node *gnode, *enode; 462 bool enable, enable_all = false; 463 const char *data; 464 465 node = xbc_node_find_child(node, "event"); 466 if (!node) 467 return; 468 /* per-event key starts with "event.GROUP.EVENT" */ 469 xbc_node_for_each_child(node, gnode) { 470 data = xbc_node_get_data(gnode); 471 if (!strcmp(data, "enable")) { 472 enable_all = true; 473 continue; 474 } 475 enable = false; 476 xbc_node_for_each_child(gnode, enode) { 477 data = xbc_node_get_data(enode); 478 if (!strcmp(data, "enable")) { 479 enable = true; 480 continue; 481 } 482 trace_boot_init_one_event(tr, gnode, enode); 483 } 484 /* Event enablement must be done after event settings */ 485 if (enable) { 486 data = xbc_node_get_data(gnode); 487 trace_array_set_clr_event(tr, data, NULL, true); 488 } 489 } 490 /* Ditto */ 491 if (enable_all) 492 trace_array_set_clr_event(tr, NULL, NULL, true); 493 } 494 #else 495 #define trace_boot_enable_events(tr, node) do {} while (0) 496 #define trace_boot_init_events(tr, node) do {} while (0) 497 #endif 498 499 #ifdef CONFIG_DYNAMIC_FTRACE 500 static void __init 501 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node) 502 { 503 struct xbc_node *anode; 504 const char *p; 505 char *q; 506 507 xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) { 508 q = kstrdup(p, GFP_KERNEL); 509 if (!q) 510 return; 511 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0) 512 pr_err("Failed to add %s to ftrace filter\n", p); 513 else 514 ftrace_filter_param = true; 515 kfree(q); 516 } 517 xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) { 518 q = kstrdup(p, GFP_KERNEL); 519 if (!q) 520 return; 521 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0) 522 pr_err("Failed to add %s to ftrace filter\n", p); 523 else 524 ftrace_filter_param = true; 525 kfree(q); 526 } 527 } 528 #else 529 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0) 530 #endif 531 532 static void __init 533 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node) 534 { 535 const char *p; 536 537 trace_boot_set_ftrace_filter(tr, node); 538 539 p = xbc_node_find_value(node, "tracer", NULL); 540 if (p && *p != '\0') { 541 if (tracing_set_tracer(tr, p) < 0) 542 pr_err("Failed to set given tracer: %s\n", p); 543 } 544 545 /* Since tracer can free snapshot buffer, allocate snapshot here.*/ 546 if (xbc_node_find_value(node, "alloc_snapshot", NULL)) { 547 if (tracing_alloc_snapshot_instance(tr) < 0) 548 pr_err("Failed to allocate snapshot buffer\n"); 549 } 550 } 551 552 static void __init 553 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node) 554 { 555 trace_boot_set_instance_options(tr, node); 556 trace_boot_init_events(tr, node); 557 trace_boot_enable_events(tr, node); 558 trace_boot_enable_tracer(tr, node); 559 } 560 561 static void __init 562 trace_boot_init_instances(struct xbc_node *node) 563 { 564 struct xbc_node *inode; 565 struct trace_array *tr; 566 const char *p; 567 568 node = xbc_node_find_child(node, "instance"); 569 if (!node) 570 return; 571 572 xbc_node_for_each_child(node, inode) { 573 p = xbc_node_get_data(inode); 574 if (!p || *p == '\0') 575 continue; 576 577 tr = trace_array_get_by_name(p); 578 if (!tr) { 579 pr_err("Failed to get trace instance %s\n", p); 580 continue; 581 } 582 trace_boot_init_one_instance(tr, inode); 583 trace_array_put(tr); 584 } 585 } 586 587 static int __init trace_boot_init(void) 588 { 589 struct xbc_node *trace_node; 590 struct trace_array *tr; 591 592 trace_node = xbc_find_node("ftrace"); 593 if (!trace_node) 594 return 0; 595 596 tr = top_trace_array(); 597 if (!tr) 598 return 0; 599 600 /* Global trace array is also one instance */ 601 trace_boot_init_one_instance(tr, trace_node); 602 trace_boot_init_instances(trace_node); 603 604 disable_tracing_selftest("running boot-time tracing"); 605 606 return 0; 607 } 608 /* 609 * Start tracing at the end of core-initcall, so that it starts tracing 610 * from the beginning of postcore_initcall. 611 */ 612 core_initcall_sync(trace_boot_init); 613