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
24static void __init
25trace_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
82static void __init
83trace_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
101static int __init
102trace_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
129static inline int __init
130trace_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
138static int __init
139trace_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
166static inline int __init
167trace_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
175static int __init __printf(3, 4)
176append_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
197static int __init
198append_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
218static int __init
219trace_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
246static int __init
247trace_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
297static int __init
298trace_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 */
345static int __init
346trace_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
418static void __init
419trace_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
453static void __init
454trace_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
461static void __init
462trace_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	}
513out:
514	mutex_unlock(&event_mutex);
515}
516
517static void __init
518trace_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
559static void __init
560trace_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
591static void __init
592trace_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
611static void __init
612trace_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
620static void __init
621trace_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
646static 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 */
671core_initcall_sync(trace_boot_init);
672