summaryrefslogtreecommitdiff
path: root/kernel/trace/trace_boot.c
blob: db6ee372dc6dea7bd14467f8ef1acdd771d640d0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
// SPDX-License-Identifier: GPL-2.0
/*
 * trace_boot.c
 * Tracing kernel boot-time
 */

#define pr_fmt(fmt)	"trace_boot: " fmt

#include <linux/bootconfig.h>
#include <linux/cpumask.h>
#include <linux/ftrace.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/trace.h>
#include <linux/trace_events.h>

#include "trace.h"

#define MAX_BUF_LEN 256

static void __init
trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
{
	struct xbc_node *anode;
	const char *p;
	char buf[MAX_BUF_LEN];
	unsigned long v = 0;

	/* Common ftrace options */
	xbc_node_for_each_array_value(node, "options", anode, p) {
		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
			pr_err("String is too long: %s\n", p);
			continue;
		}

		if (trace_set_options(tr, buf) < 0)
			pr_err("Failed to set option: %s\n", buf);
	}

	p = xbc_node_find_value(node, "tracing_on", NULL);
	if (p && *p != '\0') {
		if (kstrtoul(p, 10, &v))
			pr_err("Failed to set tracing on: %s\n", p);
		if (v)
			tracer_tracing_on(tr);
		else
			tracer_tracing_off(tr);
	}

	p = xbc_node_find_value(node, "trace_clock", NULL);
	if (p && *p != '\0') {
		if (tracing_set_clock(tr, p) < 0)
			pr_err("Failed to set trace clock: %s\n", p);
	}

	p = xbc_node_find_value(node, "buffer_size", NULL);
	if (p && *p != '\0') {
		v = memparse(p, NULL);
		if (v < PAGE_SIZE)
			pr_err("Buffer size is too small: %s\n", p);
		if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
			pr_err("Failed to resize trace buffer to %s\n", p);
	}

	p = xbc_node_find_value(node, "cpumask", NULL);
	if (p && *p != '\0') {
		cpumask_var_t new_mask;

		if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
			if (cpumask_parse(p, new_mask) < 0 ||
			    tracing_set_cpumask(tr, new_mask) < 0)
				pr_err("Failed to set new CPU mask %s\n", p);
			free_cpumask_var(new_mask);
		}
	}
}

#ifdef CONFIG_EVENT_TRACING
static void __init
trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
{
	struct xbc_node *anode;
	char buf[MAX_BUF_LEN];
	const char *p;

	xbc_node_for_each_array_value(node, "events", anode, p) {
		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf)) {
			pr_err("String is too long: %s\n", p);
			continue;
		}

		if (ftrace_set_clr_event(tr, buf, 1) < 0)
			pr_err("Failed to enable event: %s\n", p);
	}
}

#ifdef CONFIG_KPROBE_EVENTS
static int __init
trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
{
	struct dynevent_cmd cmd;
	struct xbc_node *anode;
	char buf[MAX_BUF_LEN];
	const char *val;
	int ret = 0;

	xbc_node_for_each_array_value(node, "probes", anode, val) {
		kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);

		ret = kprobe_event_gen_cmd_start(&cmd, event, val);
		if (ret) {
			pr_err("Failed to generate probe: %s\n", buf);
			break;
		}

		ret = kprobe_event_gen_cmd_end(&cmd);
		if (ret) {
			pr_err("Failed to add probe: %s\n", buf);
			break;
		}
	}

	return ret;
}
#else
static inline int __init
trace_boot_add_kprobe_event(struct xbc_node *node, const char *event)
{
	pr_err("Kprobe event is not supported.\n");
	return -ENOTSUPP;
}
#endif

#ifdef CONFIG_SYNTH_EVENTS
static int __init
trace_boot_add_synth_event(struct xbc_node *node, const char *event)
{
	struct dynevent_cmd cmd;
	struct xbc_node *anode;
	char buf[MAX_BUF_LEN];
	const char *p;
	int ret;

	synth_event_cmd_init(&cmd, buf, MAX_BUF_LEN);

	ret = synth_event_gen_cmd_start(&cmd, event, NULL);
	if (ret)
		return ret;

	xbc_node_for_each_array_value(node, "fields", anode, p) {
		ret = synth_event_add_field_str(&cmd, p);
		if (ret)
			return ret;
	}

	ret = synth_event_gen_cmd_end(&cmd);
	if (ret < 0)
		pr_err("Failed to add synthetic event: %s\n", buf);

	return ret;
}
#else
static inline int __init
trace_boot_add_synth_event(struct xbc_node *node, const char *event)
{
	pr_err("Synthetic event is not supported.\n");
	return -ENOTSUPP;
}
#endif

#ifdef CONFIG_HIST_TRIGGERS
static int __init __printf(3, 4)
append_printf(char **bufp, char *end, const char *fmt, ...)
{
	va_list args;
	int ret;

	if (*bufp == end)
		return -ENOSPC;

	va_start(args, fmt);
	ret = vsnprintf(*bufp, end - *bufp, fmt, args);
	if (ret < end - *bufp) {
		*bufp += ret;
	} else {
		*bufp = end;
		ret = -ERANGE;
	}
	va_end(args);

	return ret;
}

static int __init
append_str_nospace(char **bufp, char *end, const char *str)
{
	char *p = *bufp;
	int len;

	while (p < end - 1 && *str != '\0') {
		if (!isspace(*str))
			*(p++) = *str;
		str++;
	}
	*p = '\0';
	if (p == end - 1) {
		*bufp = end;
		return -ENOSPC;
	}
	len = p - *bufp;
	*bufp = p;
	return (int)len;
}

static int __init
trace_boot_hist_add_array(struct xbc_node *hnode, char **bufp,
			  char *end, const char *key)
{
	struct xbc_node *anode;
	const char *p;
	char sep;

	p = xbc_node_find_value(hnode, key, &anode);
	if (p) {
		if (!anode) {
			pr_err("hist.%s requires value(s).\n", key);
			return -EINVAL;
		}

		append_printf(bufp, end, ":%s", key);
		sep = '=';
		xbc_array_for_each_value(anode, p) {
			append_printf(bufp, end, "%c%s", sep, p);
			if (sep == '=')
				sep = ',';
		}
	} else
		return -ENOENT;

	return 0;
}

static int __init
trace_boot_hist_add_one_handler(struct xbc_node *hnode, char **bufp,
				char *end, const char *handler,
				const char *param)
{
	struct xbc_node *knode, *anode;
	const char *p;
	char sep;

	/* Compose 'handler' parameter */
	p = xbc_node_find_value(hnode, param, NULL);
	if (!p) {
		pr_err("hist.%s requires '%s' option.\n",
		       xbc_node_get_data(hnode), param);
		return -EINVAL;
	}
	append_printf(bufp, end, ":%s(%s)", handler, p);

	/* Compose 'action' parameter */
	knode = xbc_node_find_child(hnode, "trace");
	if (!knode)
		knode = xbc_node_find_child(hnode, "save");

	if (knode) {
		anode = xbc_node_get_child(knode);
		if (!anode || !xbc_node_is_value(anode)) {
			pr_err("hist.%s.%s requires value(s).\n",
			       xbc_node_get_data(hnode),
			       xbc_node_get_data(knode));
			return -EINVAL;
		}

		append_printf(bufp, end, ".%s", xbc_node_get_data(knode));
		sep = '(';
		xbc_array_for_each_value(anode, p) {
			append_printf(bufp, end, "%c%s", sep, p);
			if (sep == '(')
				sep = ',';
		}
		append_printf(bufp, end, ")");
	} else if (xbc_node_find_child(hnode, "snapshot")) {
		append_printf(bufp, end, ".snapshot()");
	} else {
		pr_err("hist.%s requires an action.\n",
		       xbc_node_get_data(hnode));
		return -EINVAL;
	}

	return 0;
}

static int __init
trace_boot_hist_add_handlers(struct xbc_node *hnode, char **bufp,
			     char *end, const char *param)
{
	struct xbc_node *node;
	const char *p, *handler;
	int ret;

	handler = xbc_node_get_data(hnode);

	xbc_node_for_each_subkey(hnode, node) {
		p = xbc_node_get_data(node);
		if (!isdigit(p[0]))
			continue;
		/* All digit started node should be instances. */
		ret = trace_boot_hist_add_one_handler(node, bufp, end, handler, param);
		if (ret < 0)
			break;
	}

	if (xbc_node_find_child(hnode, param))
		ret = trace_boot_hist_add_one_handler(hnode, bufp, end, handler, param);

	return ret;
}

/*
 * Histogram boottime tracing syntax.
 *
 * ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist[.N] {
 *	keys = <KEY>[,...]
 *	values = <VAL>[,...]
 *	sort = <SORT-KEY>[,...]
 *	size = <ENTRIES>
 *	name = <HISTNAME>
 *	var { <VAR> = <EXPR> ... }
 *	pause|continue|clear
 *	onmax|onchange[.N] { var = <VAR>; <ACTION> [= <PARAM>] }
 *	onmatch[.N] { event = <EVENT>; <ACTION> [= <PARAM>] }
 *	filter = <FILTER>
 * }
 *
 * Where <ACTION> are;
 *
 *	trace = <EVENT>, <ARG1>[, ...]
 *	save = <ARG1>[, ...]
 *	snapshot
 */
static int __init
trace_boot_compose_hist_cmd(struct xbc_node *hnode, char *buf, size_t size)
{
	struct xbc_node *node, *knode;
	char *end = buf + size;
	const char *p;
	int ret = 0;

	append_printf(&buf, end, "hist");

	ret = trace_boot_hist_add_array(hnode, &buf, end, "keys");
	if (ret < 0) {
		if (ret == -ENOENT)
			pr_err("hist requires keys.\n");
		return -EINVAL;
	}

	ret = trace_boot_hist_add_array(hnode, &buf, end, "values");
	if (ret == -EINVAL)
		return ret;
	ret = trace_boot_hist_add_array(hnode, &buf, end, "sort");
	if (ret == -EINVAL)
		return ret;

	p = xbc_node_find_value(hnode, "size", NULL);
	if (p)
		append_printf(&buf, end, ":size=%s", p);

	p = xbc_node_find_value(hnode, "name", NULL);
	if (p)
		append_printf(&buf, end, ":name=%s", p);

	node = xbc_node_find_child(hnode, "var");
	if (node) {
		xbc_node_for_each_key_value(node, knode, p) {
			/* Expression must not include spaces. */
			append_printf(&buf, end, ":%s=",
				      xbc_node_get_data(knode));
			append_str_nospace(&buf, end, p);
		}
	}

	/* Histogram control attributes (mutual exclusive) */
	if (xbc_node_find_value(hnode, "pause", NULL))
		append_printf(&buf, end, ":pause");
	else if (xbc_node_find_value(hnode, "continue", NULL))
		append_printf(&buf, end, ":continue");
	else if (xbc_node_find_value(hnode, "clear", NULL))
		append_printf(&buf, end, ":clear");

	/* Histogram handler and actions */
	node = xbc_node_find_child(hnode, "onmax");
	if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
		return -EINVAL;
	node = xbc_node_find_child(hnode, "onchange");
	if (node && trace_boot_hist_add_handlers(node, &buf, end, "var") < 0)
		return -EINVAL;
	node = xbc_node_find_child(hnode, "onmatch");
	if (node && trace_boot_hist_add_handlers(node, &buf, end, "event") < 0)
		return -EINVAL;

	p = xbc_node_find_value(hnode, "filter", NULL);
	if (p)
		append_printf(&buf, end, " if %s", p);

	if (buf == end) {
		pr_err("hist exceeds the max command length.\n");
		return -E2BIG;
	}

	return 0;
}

static void __init
trace_boot_init_histograms(struct trace_event_file *file,
			   struct xbc_node *hnode, char *buf, size_t size)
{
	struct xbc_node *node;
	const char *p;
	char *tmp;

	xbc_node_for_each_subkey(hnode, node) {
		p = xbc_node_get_data(node);
		if (!isdigit(p[0]))
			continue;
		/* All digit started node should be instances. */
		if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
			tmp = kstrdup(buf, GFP_KERNEL);
			if (trigger_process_regex(file, buf) < 0)
				pr_err("Failed to apply hist trigger: %s\n", tmp);
			kfree(tmp);
		}
	}

	if (xbc_node_find_child(hnode, "keys")) {
		if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
			tmp = kstrdup(buf, GFP_KERNEL);
			if (trigger_process_regex(file, buf) < 0)
				pr_err("Failed to apply hist trigger: %s\n", tmp);
			kfree(tmp);
		}
	}
}
#else
static void __init
trace_boot_init_histograms(struct trace_event_file *file,
			   struct xbc_node *hnode, char *buf, size_t size)
{
	/* do nothing */
}
#endif

static void __init
trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,
			  struct xbc_node *enode)
{
	struct trace_event_file *file;
	struct xbc_node *anode;
	char buf[MAX_BUF_LEN];
	const char *p, *group, *event;

	group = xbc_node_get_data(gnode);
	event = xbc_node_get_data(enode);

	if (!strcmp(group, "kprobes"))
		if (trace_boot_add_kprobe_event(enode, event) < 0)
			return;
	if (!strcmp(group, "synthetic"))
		if (trace_boot_add_synth_event(enode, event) < 0)
			return;

	mutex_lock(&event_mutex);
	file = find_event_file(tr, group, event);
	if (!file) {
		pr_err("Failed to find event: %s:%s\n", group, event);
		goto out;
	}

	p = xbc_node_find_value(enode, "filter", NULL);
	if (p && *p != '\0') {
		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
			pr_err("filter string is too long: %s\n", p);
		else if (apply_event_filter(file, buf) < 0)
			pr_err("Failed to apply filter: %s\n", buf);
	}

	if (IS_ENABLED(CONFIG_HIST_TRIGGERS)) {
		xbc_node_for_each_array_value(enode, "actions", anode, p) {
			if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))
				pr_err("action string is too long: %s\n", p);
			else if (trigger_process_regex(file, buf) < 0)
				pr_err("Failed to apply an action: %s\n", p);
		}
		anode = xbc_node_find_child(enode, "hist");
		if (anode)
			trace_boot_init_histograms(file, anode, buf, ARRAY_SIZE(buf));
	} else if (xbc_node_find_value(enode, "actions", NULL))
		pr_err("Failed to apply event actions because CONFIG_HIST_TRIGGERS is not set.\n");

	if (xbc_node_find_value(enode, "enable", NULL)) {
		if (trace_event_enable_disable(file, 1, 0) < 0)
			pr_err("Failed to enable event node: %s:%s\n",
				group, event);
	}
out:
	mutex_unlock(&event_mutex);
}

static void __init
trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)
{
	struct xbc_node *gnode, *enode;
	bool enable, enable_all = false;
	const char *data;

	node = xbc_node_find_child(node, "event");
	if (!node)
		return;
	/* per-event key starts with "event.GROUP.EVENT" */
	xbc_node_for_each_subkey(node, gnode) {
		data = xbc_node_get_data(gnode);
		if (!strcmp(data, "enable")) {
			enable_all = true;
			continue;
		}
		enable = false;
		xbc_node_for_each_subkey(gnode, enode) {
			data = xbc_node_get_data(enode);
			if (!strcmp(data, "enable")) {
				enable = true;
				continue;
			}
			trace_boot_init_one_event(tr, gnode, enode);
		}
		/* Event enablement must be done after event settings */
		if (enable) {
			data = xbc_node_get_data(gnode);
			trace_array_set_clr_event(tr, data, NULL, true);
		}
	}
	/* Ditto */
	if (enable_all)
		trace_array_set_clr_event(tr, NULL, NULL, true);
}
#else
#define trace_boot_enable_events(tr, node) do {} while (0)
#define trace_boot_init_events(tr, node) do {} while (0)
#endif

#ifdef CONFIG_DYNAMIC_FTRACE
static void __init
trace_boot_set_ftrace_filter(struct trace_array *tr, struct xbc_node *node)
{
	struct xbc_node *anode;
	const char *p;
	char *q;

	xbc_node_for_each_array_value(node, "ftrace.filters", anode, p) {
		q = kstrdup(p, GFP_KERNEL);
		if (!q)
			return;
		if (ftrace_set_filter(tr->ops, q, strlen(q), 0) < 0)
			pr_err("Failed to add %s to ftrace filter\n", p);
		else
			ftrace_filter_param = true;
		kfree(q);
	}
	xbc_node_for_each_array_value(node, "ftrace.notraces", anode, p) {
		q = kstrdup(p, GFP_KERNEL);
		if (!q)
			return;
		if (ftrace_set_notrace(tr->ops, q, strlen(q), 0) < 0)
			pr_err("Failed to add %s to ftrace filter\n", p);
		else
			ftrace_filter_param = true;
		kfree(q);
	}
}
#else
#define trace_boot_set_ftrace_filter(tr, node) do {} while (0)
#endif

static void __init
trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node)
{
	const char *p;

	trace_boot_set_ftrace_filter(tr, node);

	p = xbc_node_find_value(node, "tracer", NULL);
	if (p && *p != '\0') {
		if (tracing_set_tracer(tr, p) < 0)
			pr_err("Failed to set given tracer: %s\n", p);
	}

	/* Since tracer can free snapshot buffer, allocate snapshot here.*/
	if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
		if (tracing_alloc_snapshot_instance(tr) < 0)
			pr_err("Failed to allocate snapshot buffer\n");
	}
}

static void __init
trace_boot_init_one_instance(struct trace_array *tr, struct xbc_node *node)
{
	trace_boot_set_instance_options(tr, node);
	trace_boot_init_events(tr, node);
	trace_boot_enable_events(tr, node);
	trace_boot_enable_tracer(tr, node);
}

static void __init
trace_boot_init_instances(struct xbc_node *node)
{
	struct xbc_node *inode;
	struct trace_array *tr;
	const char *p;

	node = xbc_node_find_child(node, "instance");
	if (!node)
		return;

	xbc_node_for_each_subkey(node, inode) {
		p = xbc_node_get_data(inode);
		if (!p || *p == '\0')
			continue;

		tr = trace_array_get_by_name(p);
		if (!tr) {
			pr_err("Failed to get trace instance %s\n", p);
			continue;
		}
		trace_boot_init_one_instance(tr, inode);
		trace_array_put(tr);
	}
}

static int __init trace_boot_init(void)
{
	struct xbc_node *trace_node;
	struct trace_array *tr;

	trace_node = xbc_find_node("ftrace");
	if (!trace_node)
		return 0;

	tr = top_trace_array();
	if (!tr)
		return 0;

	/* Global trace array is also one instance */
	trace_boot_init_one_instance(tr, trace_node);
	trace_boot_init_instances(trace_node);

	disable_tracing_selftest("running boot-time tracing");

	return 0;
}
/*
 * Start tracing at the end of core-initcall, so that it starts tracing
 * from the beginning of postcore_initcall.
 */
core_initcall_sync(trace_boot_init);