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_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);