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 (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) {
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 (strscpy(buf, p, ARRAY_SIZE(buf)) < 0) {
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 (strscpy(buf, p, ARRAY_SIZE(buf)) < 0)
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 (strscpy(buf, p, ARRAY_SIZE(buf)) < 0)
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, NULL);
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);
672
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