kernel/trace/trace_boot.c

   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 *anode;
 223         const char *p;
 224         char sep;
 225
 226         p = xbc_node_find_value(hnode, key, &anode);
 227         if (p) {
 228                 if (!anode) {
 229                         pr_err("hist.%s requires value(s).\n", key);
 230                         return -EINVAL;
 231                 }
 232
 233                 append_printf(bufp, end, ":%s", key);
 234                 sep = '=';
 235                 xbc_array_for_each_value(anode, p) {
 236                         append_printf(bufp, end, "%c%s", sep, p);
 237                         if (sep == '=')
 238                                 sep = ',';
 239                 }
 240         } else
 241                 return -ENOENT;
 242
 243         return 0;
 244 }
 245
 246 static int __init
 247 trace_boot_hist_add_one_handler(struct xbc_node *hnode, char **bufp,
 248                                 char *end, const char *handler,
 249                                 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)", handler, p);
 263
 264         /* Compose 'action' parameter */
 265         knode = xbc_node_find_subkey(hnode, "trace");
 266         if (!knode)
 267                 knode = xbc_node_find_subkey(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_subkey(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 static int __init
 298 trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
 299                              char *end, const char *param)
 300 {
 301         struct xbc_node *node;
 302         const char *p, *handler;
 303         int ret = 0;
 304
 305         handler = xbc_node_get_data(hnode);
 306
 307         xbc_node_for_each_subkey(hnode, node) {
 308                 p = xbc_node_get_data(node);
 309                 if (!isdigit(p[0]))
 310                         continue;
 311                 /* All digit started node should be instances. */
 312                 ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param);
 313                 if (ret < 0)
 314                         break;
 315         }
 316
 317         if (xbc_node_find_subkey(hnode, param))
 318                 ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);
 319
 320         return ret;
 321 }
 322
 323 /*
 324  * Histogram boottime tracing syntax.
 325  *
 326  * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
 327  *      keys = <KEY>[,...]
 328  *      values = <VAL>[,...]
 329  *      sort = <SORT-KEY>[,...]
 330  *      size = <ENTRIES>
 331  *      name = <HISTNAME>
 332  *      var { <VAR> = <EXPR> ... }
 333  *      pause|continue|clear
 334  *      onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
 335  *      onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
 336  *      filter = <FILTER>
 337  * }
 338  *
 339  * Where <ACTION> are;
 340  *
 341  *      trace = <EVENT>, <ARG1>[, ...]
 342  *      save = <ARG1>[, ...]
 343  *      snapshot
 344  */
 345 static int __init
 346 trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
 347 {
 348         struct xbc_node *node, *knode;
 349         char *end = buf + size;
 350         const char *p;
 351         int ret = 0;
 352
 353         append_printf(&buf, end, "hist");
 354
 355         ret = trace_boot_hist_add_array(hnode, &buf, end, "keys");
 356         if (ret < 0) {
 357                 if (ret == -ENOENT)
 358                         pr_err("hist requires keys.\n");
 359                 return -EINVAL;
 360         }
 361
 362         ret = trace_boot_hist_add_array(hnode, &buf, end, "values");
 363         if (ret == -EINVAL)
 364                 return ret;
 365         ret = trace_boot_hist_add_array(hnode, &buf, end, "sort");
 366         if (ret == -EINVAL)
 367                 return ret;
 368
 369         p = xbc_node_find_value(hnode, "size", NULL);
 370         if (p)
 371                 append_printf(&buf, end, ":size=%s", p);
 372
 373         p = xbc_node_find_value(hnode, "name", NULL);
 374         if (p)
 375                 append_printf(&buf, end, ":name=%s", p);
 376
 377         node = xbc_node_find_subkey(hnode, "var");
 378         if (node) {
 379                 xbc_node_for_each_key_value(node, knode, p) {
 380                         /* Expression must not include spaces. */
 381                         append_printf(&buf, end, ":%s=",
 382                                       xbc_node_get_data(knode));
 383                         append_str_nospace(&buf, end, p);
 384                 }
 385         }
 386
 387         /* Histogram control attributes (mutual exclusive) */
 388         if (xbc_node_find_value(hnode, "pause", NULL))
 389                 append_printf(&buf, end, ":pause");
 390         else if (xbc_node_find_value(hnode, "continue", NULL))
 391                 append_printf(&buf, end, ":continue");
 392         else if (xbc_node_find_value(hnode, "clear", NULL))
 393                 append_printf(&buf, end, ":clear");
 394
 395         /* Histogram handler and actions */
 396         node = xbc_node_find_subkey(hnode, "onmax");
 397         if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
 398                 return -EINVAL;
 399         node = xbc_node_find_subkey(hnode, "onchange");
 400         if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
 401                 return -EINVAL;
 402         node = xbc_node_find_subkey(hnode, "onmatch");
 403         if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0)
 404                 return -EINVAL;
 405
 406         p = xbc_node_find_value(hnode, "filter", NULL);
 407         if (p)
 408                 append_printf(&buf, end, " if %s", p);
 409
 410         if (buf == end) {
 411                 pr_err("hist exceeds the max command length.\n");
 412                 return -E2BIG;
 413         }
 414
 415         return 0;
 416 }
 417
 418 static void __init
 419 trace_boot_init_histograms(struct trace_event_file *file,
 420                            struct xbc_node *hnode, char *buf, size_t size)
 421 {
 422         struct xbc_node *node;
 423         const char *p;
 424         char *tmp;
 425
 426         xbc_node_for_each_subkey(hnode, node) {
 427                 p = xbc_node_get_data(node);
 428                 if (!isdigit(p[0]))
 429                         continue;
 430                 /* All digit started node should be instances. */
 431                 if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
 432                         tmp = kstrdup(buf, GFP_KERNEL);
 433                         if (!tmp)
 434                                 return;
 435                         if (trigger_process_regex(file, buf) < 0)
 436                                 pr_err("Failed to apply hist trigger: %s\n", tmp);
 437                         kfree(tmp);
 438                 }
 439         }
 440
 441         if (xbc_node_find_subkey(hnode, "keys")) {
 442                 if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
 443                         tmp = kstrdup(buf, GFP_KERNEL);
 444                         if (!tmp)
 445                                 return;
 446                         if (trigger_process_regex(file, buf) < 0)
 447                                 pr_err("Failed to apply hist trigger: %s\n", tmp);
 448                         kfree(tmp);
 449                 }
 450         }
 451 }
 452 #else
 453 static void __init
 454 trace_boot_init_histograms(struct trace_event_file *file,
 455                            struct xbc_node *hnode, char *buf, size_t size)
 456 {
 457         /* do nothing */
 458 }
 459 #endif
 460
 461 static void __init
 462 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 463                           struct xbc_node *enode)
 464 {
 465         struct trace_event_file *file;
 466         struct xbc_node *anode;
 467         char buf[MAX_BUF_LEN];
 468         const char *p, *group, *event;
 469
 470         group = xbc_node_get_data(gnode);
 471         event = xbc_node_get_data(enode);
 472
 473         if (!strcmp(group, "kprobes"))
 474                 if (trace_boot_add_kprobe_event(enode, event) < 0)
 475                         return;
 476         if (!strcmp(group, "synthetic"))
 477                 if (trace_boot_add_synth_event(enode, event) < 0)
 478                         return;
 479
 480         mutex_lock(&event_mutex);
 481         file = find_event_file(tr, group, event);
 482         if (!file) {
 483                 pr_err("Failed to find event: %s:%s\n", group, event);
 484                 goto out;
 485         }
 486
 487         p = xbc_node_find_value(enode, "filter", NULL);
 488         if (p && *p != '\0') {
 489                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 490                         pr_err("filter string is too long: %s\n", p);
 491                 else if (apply_event_filter(file, buf) < 0)
 492                         pr_err("Failed to apply filter: %s\n", buf);
 493         }
 494
 495         if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
 496                 xbc_node_for_each_array_value(enode, "actions", anode, p) {
 497                         if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 498                                 pr_err("action string is too long: %s\n", p);
 499                         else if (trigger_process_regex(file, buf) < 0)
 500                                 pr_err("Failed to apply an action: %s\n", p);
 501                 }
 502                 anode = xbc_node_find_subkey(enode, "hist");
 503                 if (anode)
 504                         trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf));
 505         } else if (xbc_node_find_value(enode, "actions", NULL))
 506                 pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
 507
 508         if (xbc_node_find_value(enode, "enable", NULL)) {
 509                 if (trace_event_enable_disable(file, 1, 0) < 0)
 510                         pr_err("Failed to enable event node: %s:%s\n",
 511                                 group, event);
 512         }
 513 out:
 514         mutex_unlock(&event_mutex);
 515 }
 516
 517 static void __init
 518 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 519 {
 520         struct xbc_node *gnode, *enode;
 521         bool enable, enable_all = false;
 522         const char *data;
 523
 524         node = xbc_node_find_subkey(node, "event");
 525         if (!node)
 526                 return;
 527         /* per-event key starts with "event.GROUP.EVENT" */
 528         xbc_node_for_each_subkey(node, gnode) {
 529                 data = xbc_node_get_data(gnode);
 530                 if (!strcmp(data, "enable")) {
 531                         enable_all = true;
 532                         continue;
 533                 }
 534                 enable = false;
 535                 xbc_node_for_each_subkey(gnode, enode) {
 536                         data = xbc_node_get_data(enode);
 537                         if (!strcmp(data, "enable")) {
 538                                 enable = true;
 539                                 continue;
 540                         }
 541                         trace_boot_init_one_event(tr, gnode, enode);
 542                 }
 543                 /* Event enablement must be done after event settings */
 544                 if (enable) {
 545                         data = xbc_node_get_data(gnode);
 546                         trace_array_set_clr_event(tr, data, NULL, true);
 547                 }
 548         }
 549         /* Ditto */
 550         if (enable_all)
 551                 trace_array_set_clr_event(tr, NULL, NULL, true);
 552 }
 553 #else
 554 #define trace_boot_enable_events(tr, node) do {} while (0)
 555 #define trace_boot_init_events(tr, node) do {} while (0)
 556 #endif
 557
 558 #ifdef CONFIG_DYNAMIC_FTRACE
 559 static void __init
 560 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 561 {
 562         struct xbc_node *anode;
 563         const char *p;
 564         char *q;
 565
 566         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 567                 q = kstrdup(p, GFP_KERNEL);
 568                 if (!q)
 569                         return;
 570                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 571                         pr_err("Failed to add %s to ftrace filter\n", p);
 572                 else
 573                         ftrace_filter_param = true;
 574                 kfree(q);
 575         }
 576         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 577                 q = kstrdup(p, GFP_KERNEL);
 578                 if (!q)
 579                         return;
 580                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 581                         pr_err("Failed to add %s to ftrace filter\n", p);
 582                 else
 583                         ftrace_filter_param = true;
 584                 kfree(q);
 585         }
 586 }
 587 #else
 588 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 589 #endif
 590
 591 static void __init
 592 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 593 {
 594         const char *p;
 595
 596         trace_boot_set_ftrace_filter(tr, node);
 597
 598         p = xbc_node_find_value(node, "tracer", NULL);
 599         if (p && *p != '\0') {
 600                 if (tracing_set_tracer(tr, p) < 0)
 601                         pr_err("Failed to set given tracer: %s\n", p);
 602         }
 603
 604         /* Since tracer can free snapshot buffer, allocate snapshot here.*/
 605         if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
 606                 if (tracing_alloc_snapshot_instance(tr) < 0)
 607                         pr_err("Failed to allocate snapshot buffer\n");
 608         }
 609 }
 610
 611 static void __init
 612 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 613 {
 614         trace_boot_set_instance_options(tr, node);
 615         trace_boot_init_events(tr, node);
 616         trace_boot_enable_events(tr, node);
 617         trace_boot_enable_tracer(tr, node);
 618 }
 619
 620 static void __init
 621 trace_boot_init_instances(struct xbc_node *node)
 622 {
 623         struct xbc_node *inode;
 624         struct trace_array *tr;
 625         const char *p;
 626
 627         node = xbc_node_find_subkey(node, "instance");
 628         if (!node)
 629                 return;
 630
 631         xbc_node_for_each_subkey(node, inode) {
 632                 p = xbc_node_get_data(inode);
 633                 if (!p || *p == '\0')
 634                         continue;
 635
 636                 tr = trace_array_get_by_name(p);
 637                 if (!tr) {
 638                         pr_err("Failed to get trace instance %s\n", p);
 639                         continue;
 640                 }
 641                 trace_boot_init_one_instance(tr, inode);
 642                 trace_array_put(tr);
 643         }
 644 }
 645
 646 static int __init trace_boot_init(void)
 647 {
 648         struct xbc_node *trace_node;
 649         struct trace_array *tr;
 650
 651         trace_node = xbc_find_node("ftrace");
 652         if (!trace_node)
 653                 return 0;
 654
 655         tr = top_trace_array();
 656         if (!tr)
 657                 return 0;
 658
 659         /* Global trace array is also one instance */
 660         trace_boot_init_one_instance(tr, trace_node);
 661         trace_boot_init_instances(trace_node);
 662
 663         disable_tracing_selftest("running boot-time tracing");
 664
 665         return 0;
 666 }
 667 /*
 668  * Start tracing at the end of core-initcall, so that it starts tracing
 669  * from the beginning of postcore_initcall.
 670  */
 671 core_initcall_sync(trace_boot_init);