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 *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_one_handler(struct xbc_node *hnode, char **bufp,
 249                                 char *end, const char *handler,
 250                                 const char *param)
 251 {
 252         struct xbc_node *knode, *anode;
 253         const char *p;
 254         char sep;
 255
 256         /* Compose 'handler' parameter */
 257         p = xbc_node_find_value(hnode, param, NULL);
 258         if (!p) {
 259                 pr_err("hist.%s requires '%s' option.\n",
 260                        xbc_node_get_data(hnode), param);
 261                 return -EINVAL;
 262         }
 263         append_printf(bufp, end, ":%s(%s)", handler, p);
 264
 265         /* Compose 'action' parameter */
 266         knode = xbc_node_find_child(hnode, "trace");
 267         if (!knode)
 268                 knode = xbc_node_find_child(hnode, "save");
 269
 270         if (knode) {
 271                 anode = xbc_node_get_child(knode);
 272                 if (!anode || !xbc_node_is_value(anode)) {
 273                         pr_err("hist.%s.%s requires value(s).\n",
 274                                xbc_node_get_data(hnode),
 275                                xbc_node_get_data(knode));
 276                         return -EINVAL;
 277                 }
 278
 279                 append_printf(bufp, end, ".%s", xbc_node_get_data(knode));
 280                 sep = '(';
 281                 xbc_array_for_each_value(anode, p) {
 282                         append_printf(bufp, end, "%c%s", sep, p);
 283                         if (sep == '(')
 284                                 sep = ',';
 285                 }
 286                 append_printf(bufp, end, ")");
 287         } else if (xbc_node_find_child(hnode, "snapshot")) {
 288                 append_printf(bufp, end, ".snapshot()");
 289         } else {
 290                 pr_err("hist.%s requires an action.\n",
 291                        xbc_node_get_data(hnode));
 292                 return -EINVAL;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int __init
 299 trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
 300                              char *end, const char *param)
 301 {
 302         struct xbc_node *node;
 303         const char *p, *handler;
 304         int ret;
 305
 306         handler = xbc_node_get_data(hnode);
 307
 308         xbc_node_for_each_subkey(hnode, node) {
 309                 p = xbc_node_get_data(node);
 310                 if (!isdigit(p[0]))
 311                         continue;
 312                 /* All digit started node should be instances. */
 313                 ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param);
 314                 if (ret < 0)
 315                         break;
 316         }
 317
 318         if (xbc_node_find_child(hnode, param))
 319                 ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);
 320
 321         return ret;
 322 }
 323
 324 /*
 325  * Histogram boottime tracing syntax.
 326  *
 327  * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
 328  *      keys = <KEY>[,...]
 329  *      values = <VAL>[,...]
 330  *      sort = <SORT-KEY>[,...]
 331  *      size = <ENTRIES>
 332  *      name = <HISTNAME>
 333  *      var { <VAR> = <EXPR> ... }
 334  *      pause|continue|clear
 335  *      onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
 336  *      onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
 337  *      filter = <FILTER>
 338  * }
 339  *
 340  * Where <ACTION> are;
 341  *
 342  *      trace = <EVENT>, <ARG1>[, ...]
 343  *      save = <ARG1>[, ...]
 344  *      snapshot
 345  */
 346 static int __init
 347 trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
 348 {
 349         struct xbc_node *node, *knode;
 350         char *end = buf + size;
 351         const char *p;
 352         int ret = 0;
 353
 354         append_printf(&buf, end, "hist");
 355
 356         ret = trace_boot_hist_add_array(hnode, &buf, end, "keys");
 357         if (ret < 0) {
 358                 if (ret == -ENOENT)
 359                         pr_err("hist requires keys.\n");
 360                 return -EINVAL;
 361         }
 362
 363         ret = trace_boot_hist_add_array(hnode, &buf, end, "values");
 364         if (ret == -EINVAL)
 365                 return ret;
 366         ret = trace_boot_hist_add_array(hnode, &buf, end, "sort");
 367         if (ret == -EINVAL)
 368                 return ret;
 369
 370         p = xbc_node_find_value(hnode, "size", NULL);
 371         if (p)
 372                 append_printf(&buf, end, ":size=%s", p);
 373
 374         p = xbc_node_find_value(hnode, "name", NULL);
 375         if (p)
 376                 append_printf(&buf, end, ":name=%s", p);
 377
 378         node = xbc_node_find_child(hnode, "var");
 379         if (node) {
 380                 xbc_node_for_each_key_value(node, knode, p) {
 381                         /* Expression must not include spaces. */
 382                         append_printf(&buf, end, ":%s=",
 383                                       xbc_node_get_data(knode));
 384                         append_str_nospace(&buf, end, p);
 385                 }
 386         }
 387
 388         /* Histogram control attributes (mutual exclusive) */
 389         if (xbc_node_find_child(hnode, "pause"))
 390                 append_printf(&buf, end, ":pause");
 391         else if (xbc_node_find_child(hnode, "continue"))
 392                 append_printf(&buf, end, ":continue");
 393         else if (xbc_node_find_child(hnode, "clear"))
 394                 append_printf(&buf, end, ":clear");
 395
 396         /* Histogram handler and actions */
 397         node = xbc_node_find_child(hnode, "onmax");
 398         if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
 399                 return -EINVAL;
 400         node = xbc_node_find_child(hnode, "onchange");
 401         if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
 402                 return -EINVAL;
 403         node = xbc_node_find_child(hnode, "onmatch");
 404         if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0)
 405                 return -EINVAL;
 406
 407         p = xbc_node_find_value(hnode, "filter", NULL);
 408         if (p)
 409                 append_printf(&buf, end, " if %s", p);
 410
 411         if (buf == end) {
 412                 pr_err("hist exceeds the max command length.\n");
 413                 return -E2BIG;
 414         }
 415
 416         return 0;
 417 }
 418
 419 static void __init
 420 trace_boot_init_histograms(struct trace_event_file *file,
 421                            struct xbc_node *hnode, char *buf, size_t size)
 422 {
 423         struct xbc_node *node;
 424         const char *p;
 425         char *tmp;
 426
 427         xbc_node_for_each_subkey(hnode, node) {
 428                 p = xbc_node_get_data(node);
 429                 if (!isdigit(p[0]))
 430                         continue;
 431                 /* All digit started node should be instances. */
 432                 if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
 433                         tmp = kstrdup(buf, GFP_KERNEL);
 434                         if (trigger_process_regex(file, buf) < 0)
 435                                 pr_err("Failed to apply hist trigger: %s\n", tmp);
 436                         kfree(tmp);
 437                 }
 438         }
 439
 440         if (xbc_node_find_child(hnode, "keys")) {
 441                 if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
 442                         tmp = kstrdup(buf, GFP_KERNEL);
 443                         if (trigger_process_regex(file, buf) < 0)
 444                                 pr_err("Failed to apply hist trigger: %s\n", tmp);
 445                         kfree(tmp);
 446                 }
 447         }
 448 }
 449 #else
 450 static void __init
 451 trace_boot_init_histograms(struct trace_event_file *file,
 452                            struct xbc_node *hnode, char *buf, size_t size)
 453 {
 454         /* do nothing */
 455 }
 456 #endif
 457
 458 static void __init
 459 trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
 460                           struct xbc_node *enode)
 461 {
 462         struct trace_event_file *file;
 463         struct xbc_node *anode;
 464         char buf[MAX_BUF_LEN];
 465         const char *p, *group, *event;
 466
 467         group = xbc_node_get_data(gnode);
 468         event = xbc_node_get_data(enode);
 469
 470         if (!strcmp(group, "kprobes"))
 471                 if (trace_boot_add_kprobe_event(enode, event) < 0)
 472                         return;
 473         if (!strcmp(group, "synthetic"))
 474                 if (trace_boot_add_synth_event(enode, event) < 0)
 475                         return;
 476
 477         mutex_lock(&event_mutex);
 478         file = find_event_file(tr, group, event);
 479         if (!file) {
 480                 pr_err("Failed to find event: %s:%s\n", group, event);
 481                 goto out;
 482         }
 483
 484         p = xbc_node_find_value(enode, "filter", NULL);
 485         if (p && *p != '\0') {
 486                 if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 487                         pr_err("filter string is too long: %s\n", p);
 488                 else if (apply_event_filter(file, buf) < 0)
 489                         pr_err("Failed to apply filter: %s\n", buf);
 490         }
 491
 492         if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
 493                 xbc_node_for_each_array_value(enode, "actions", anode, p) {
 494                         if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
 495                                 pr_err("action string is too long: %s\n", p);
 496                         else if (trigger_process_regex(file, buf) < 0)
 497                                 pr_err("Failed to apply an action: %s\n", p);
 498                 }
 499                 anode = xbc_node_find_child(enode, "hist");
 500                 if (anode)
 501                         trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf));
 502         } else if (xbc_node_find_value(enode, "actions", NULL))
 503                 pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");
 504
 505         if (xbc_node_find_value(enode, "enable", NULL)) {
 506                 if (trace_event_enable_disable(file, 1, 0) < 0)
 507                         pr_err("Failed to enable event node: %s:%s\n",
 508                                 group, event);
 509         }
 510 out:
 511         mutex_unlock(&event_mutex);
 512 }
 513
 514 static void __init
 515 trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
 516 {
 517         struct xbc_node *gnode, *enode;
 518         bool enable, enable_all = false;
 519         const char *data;
 520
 521         node = xbc_node_find_child(node, "event");
 522         if (!node)
 523                 return;
 524         /* per-event key starts with "event.GROUP.EVENT" */
 525         xbc_node_for_each_subkey(node, gnode) {
 526                 data = xbc_node_get_data(gnode);
 527                 if (!strcmp(data, "enable")) {
 528                         enable_all = true;
 529                         continue;
 530                 }
 531                 enable = false;
 532                 xbc_node_for_each_subkey(gnode, enode) {
 533                         data = xbc_node_get_data(enode);
 534                         if (!strcmp(data, "enable")) {
 535                                 enable = true;
 536                                 continue;
 537                         }
 538                         trace_boot_init_one_event(tr, gnode, enode);
 539                 }
 540                 /* Event enablement must be done after event settings */
 541                 if (enable) {
 542                         data = xbc_node_get_data(gnode);
 543                         trace_array_set_clr_event(tr, data, NULL, true);
 544                 }
 545         }
 546         /* Ditto */
 547         if (enable_all)
 548                 trace_array_set_clr_event(tr, NULL, NULL, true);
 549 }
 550 #else
 551 #define trace_boot_enable_events(tr, node) do {} while (0)
 552 #define trace_boot_init_events(tr, node) do {} while (0)
 553 #endif
 554
 555 #ifdef CONFIG_DYNAMIC_FTRACE
 556 static void __init
 557 trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
 558 {
 559         struct xbc_node *anode;
 560         const char *p;
 561         char *q;
 562
 563         xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
 564                 q = kstrdup(p, GFP_KERNEL);
 565                 if (!q)
 566                         return;
 567                 if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
 568                         pr_err("Failed to add %s to ftrace filter\n", p);
 569                 else
 570                         ftrace_filter_param = true;
 571                 kfree(q);
 572         }
 573         xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
 574                 q = kstrdup(p, GFP_KERNEL);
 575                 if (!q)
 576                         return;
 577                 if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
 578                         pr_err("Failed to add %s to ftrace filter\n", p);
 579                 else
 580                         ftrace_filter_param = true;
 581                 kfree(q);
 582         }
 583 }
 584 #else
 585 #define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
 586 #endif
 587
 588 static void __init
 589 trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
 590 {
 591         const char *p;
 592
 593         trace_boot_set_ftrace_filter(tr, node);
 594
 595         p = xbc_node_find_value(node, "tracer", NULL);
 596         if (p && *p != '\0') {
 597                 if (tracing_set_tracer(tr, p) < 0)
 598                         pr_err("Failed to set given tracer: %s\n", p);
 599         }
 600
 601         /* Since tracer can free snapshot buffer, allocate snapshot here.*/
 602         if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
 603                 if (tracing_alloc_snapshot_instance(tr) < 0)
 604                         pr_err("Failed to allocate snapshot buffer\n");
 605         }
 606 }
 607
 608 static void __init
 609 trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
 610 {
 611         trace_boot_set_instance_options(tr, node);
 612         trace_boot_init_events(tr, node);
 613         trace_boot_enable_events(tr, node);
 614         trace_boot_enable_tracer(tr, node);
 615 }
 616
 617 static void __init
 618 trace_boot_init_instances(struct xbc_node *node)
 619 {
 620         struct xbc_node *inode;
 621         struct trace_array *tr;
 622         const char *p;
 623
 624         node = xbc_node_find_child(node, "instance");
 625         if (!node)
 626                 return;
 627
 628         xbc_node_for_each_subkey(node, inode) {
 629                 p = xbc_node_get_data(inode);
 630                 if (!p || *p == '\0')
 631                         continue;
 632
 633                 tr = trace_array_get_by_name(p);
 634                 if (!tr) {
 635                         pr_err("Failed to get trace instance %s\n", p);
 636                         continue;
 637                 }
 638                 trace_boot_init_one_instance(tr, inode);
 639                 trace_array_put(tr);
 640         }
 641 }
 642
 643 static int __init trace_boot_init(void)
 644 {
 645         struct xbc_node *trace_node;
 646         struct trace_array *tr;
 647
 648         trace_node = xbc_find_node("ftrace");
 649         if (!trace_node)
 650                 return 0;
 651
 652         tr = top_trace_array();
 653         if (!tr)
 654                 return 0;
 655
 656         /* Global trace array is also one instance */
 657         trace_boot_init_one_instance(tr, trace_node);
 658         trace_boot_init_instances(trace_node);
 659
 660         disable_tracing_selftest("running boot-time tracing");
 661
 662         return 0;
 663 }
 664 /*
 665  * Start tracing at the end of core-initcall, so that it starts tracing
 666  * from the beginning of postcore_initcall.
 667  */
 668 core_initcall_sync(trace_boot_init);