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  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
  4 */
  5
  6#include <sys/types.h>
  7#include <sys/stat.h>
  8#include <pthread.h>
  9#include <stdlib.h>
 10#include <string.h>
 11#include <unistd.h>
 12#include <errno.h>
 13#include <fcntl.h>
 14#include <stdio.h>
 15
 16#include "osnoise.h"
 17#include "utils.h"
 18
 19/*
 20 * osnoise_get_cpus - return the original "osnoise/cpus" content
 21 *
 22 * It also saves the value to be restored.
 23 */
 24char *osnoise_get_cpus(struct osnoise_context *context)
 25{
 26	if (context->curr_cpus)
 27		return context->curr_cpus;
 28
 29	if (context->orig_cpus)
 30		return context->orig_cpus;
 31
 32	context->orig_cpus = tracefs_instance_file_read(NULL, "osnoise/cpus", NULL);
 33
 34	/*
 35	 * The error value (NULL) is the same for tracefs_instance_file_read()
 36	 * and this functions, so:
 37	 */
 38	return context->orig_cpus;
 39}
 40
 41/*
 42 * osnoise_set_cpus - configure osnoise to run on *cpus
 43 *
 44 * "osnoise/cpus" file is used to set the cpus in which osnoise/timerlat
 45 * will run. This function opens this file, saves the current value,
 46 * and set the cpus passed as argument.
 47 */
 48int osnoise_set_cpus(struct osnoise_context *context, char *cpus)
 49{
 50	char *orig_cpus = osnoise_get_cpus(context);
 51	char buffer[1024];
 52	int retval;
 53
 54	if (!orig_cpus)
 55		return -1;
 56
 57	context->curr_cpus = strdup(cpus);
 58	if (!context->curr_cpus)
 59		return -1;
 60
 61	snprintf(buffer, 1024, "%s\n", cpus);
 62
 63	debug_msg("setting cpus to %s from %s", cpus, context->orig_cpus);
 64
 65	retval = tracefs_instance_file_write(NULL, "osnoise/cpus", buffer);
 66	if (retval < 0) {
 67		free(context->curr_cpus);
 68		context->curr_cpus = NULL;
 69		return -1;
 70	}
 71
 72	return 0;
 73}
 74
 75/*
 76 * osnoise_restore_cpus - restore the original "osnoise/cpus"
 77 *
 78 * osnoise_set_cpus() saves the original data for the "osnoise/cpus"
 79 * file. This function restore the original config it was previously
 80 * modified.
 81 */
 82void osnoise_restore_cpus(struct osnoise_context *context)
 83{
 84	int retval;
 85
 86	if (!context->orig_cpus)
 87		return;
 88
 89	if (!context->curr_cpus)
 90		return;
 91
 92	/* nothing to do? */
 93	if (!strcmp(context->orig_cpus, context->curr_cpus))
 94		goto out_done;
 95
 96	debug_msg("restoring cpus to %s", context->orig_cpus);
 97
 98	retval = tracefs_instance_file_write(NULL, "osnoise/cpus", context->orig_cpus);
 99	if (retval < 0)
100		err_msg("could not restore original osnoise cpus\n");
101
102out_done:
103	free(context->curr_cpus);
104	context->curr_cpus = NULL;
105}
106
107/*
108 * osnoise_put_cpus - restore cpus config and cleanup data
109 */
110void osnoise_put_cpus(struct osnoise_context *context)
111{
112	osnoise_restore_cpus(context);
113
114	if (!context->orig_cpus)
115		return;
116
117	free(context->orig_cpus);
118	context->orig_cpus = NULL;
119}
120
121/*
122 * osnoise_read_ll_config - read a long long value from a config
123 *
124 * returns -1 on error.
125 */
126static long long osnoise_read_ll_config(char *rel_path)
127{
128	long long retval;
129	char *buffer;
130
131	buffer = tracefs_instance_file_read(NULL, rel_path, NULL);
132	if (!buffer)
133		return -1;
134
135	/* get_llong_from_str returns -1 on error */
136	retval = get_llong_from_str(buffer);
137
138	debug_msg("reading %s returned %lld\n", rel_path, retval);
139
140	free(buffer);
141
142	return retval;
143}
144
145/*
146 * osnoise_write_ll_config - write a long long value to a config in rel_path
147 *
148 * returns -1 on error.
149 */
150static long long osnoise_write_ll_config(char *rel_path, long long value)
151{
152	char buffer[BUFF_U64_STR_SIZE];
153	long long retval;
154
155	snprintf(buffer, sizeof(buffer), "%lld\n", value);
156
157	debug_msg("setting %s to %lld\n", rel_path, value);
158
159	retval = tracefs_instance_file_write(NULL, rel_path, buffer);
160	return retval;
161}
162
163/*
164 * osnoise_get_runtime - return the original "osnoise/runtime_us" value
165 *
166 * It also saves the value to be restored.
167 */
168unsigned long long osnoise_get_runtime(struct osnoise_context *context)
169{
170	long long runtime_us;
171
172	if (context->runtime_us != OSNOISE_TIME_INIT_VAL)
173		return context->runtime_us;
174
175	if (context->orig_runtime_us != OSNOISE_TIME_INIT_VAL)
176		return context->orig_runtime_us;
177
178	runtime_us = osnoise_read_ll_config("osnoise/runtime_us");
179	if (runtime_us < 0)
180		goto out_err;
181
182	context->orig_runtime_us = runtime_us;
183	return runtime_us;
184
185out_err:
186	return OSNOISE_TIME_INIT_VAL;
187}
188
189/*
190 * osnoise_get_period - return the original "osnoise/period_us" value
191 *
192 * It also saves the value to be restored.
193 */
194unsigned long long osnoise_get_period(struct osnoise_context *context)
195{
196	long long period_us;
197
198	if (context->period_us != OSNOISE_TIME_INIT_VAL)
199		return context->period_us;
200
201	if (context->orig_period_us != OSNOISE_TIME_INIT_VAL)
202		return context->orig_period_us;
203
204	period_us = osnoise_read_ll_config("osnoise/period_us");
205	if (period_us < 0)
206		goto out_err;
207
208	context->orig_period_us = period_us;
209	return period_us;
210
211out_err:
212	return OSNOISE_TIME_INIT_VAL;
213}
214
215static int __osnoise_write_runtime(struct osnoise_context *context,
216				   unsigned long long runtime)
217{
218	int retval;
219
220	if (context->orig_runtime_us == OSNOISE_TIME_INIT_VAL)
221		return -1;
222
223	retval = osnoise_write_ll_config("osnoise/runtime_us", runtime);
224	if (retval < 0)
225		return -1;
226
227	context->runtime_us = runtime;
228	return 0;
229}
230
231static int __osnoise_write_period(struct osnoise_context *context,
232				  unsigned long long period)
233{
234	int retval;
235
236	if (context->orig_period_us == OSNOISE_TIME_INIT_VAL)
237		return -1;
238
239	retval = osnoise_write_ll_config("osnoise/period_us", period);
240	if (retval < 0)
241		return -1;
242
243	context->period_us = period;
244	return 0;
245}
246
247/*
248 * osnoise_set_runtime_period - set osnoise runtime and period
249 *
250 * Osnoise's runtime and period are related as runtime <= period.
251 * Thus, this function saves the original values, and then tries
252 * to set the runtime and period if they are != 0.
253 */
254int osnoise_set_runtime_period(struct osnoise_context *context,
255			       unsigned long long runtime,
256			       unsigned long long period)
257{
258	unsigned long long curr_runtime_us;
259	unsigned long long curr_period_us;
260	int retval;
261
262	if (!period && !runtime)
263		return 0;
264
265	curr_runtime_us = osnoise_get_runtime(context);
266	curr_period_us = osnoise_get_period(context);
267
268	/* error getting any value? */
269	if (curr_period_us == OSNOISE_TIME_INIT_VAL || curr_runtime_us == OSNOISE_TIME_INIT_VAL)
270		return -1;
271
272	if (!period) {
273		if (runtime > curr_period_us)
274			return -1;
275		return __osnoise_write_runtime(context, runtime);
276	} else if (!runtime) {
277		if (period < curr_runtime_us)
278			return -1;
279		return __osnoise_write_period(context, period);
280	}
281
282	if (runtime > curr_period_us) {
283		retval = __osnoise_write_period(context, period);
284		if (retval)
285			return -1;
286		retval = __osnoise_write_runtime(context, runtime);
287		if (retval)
288			return -1;
289	} else {
290		retval = __osnoise_write_runtime(context, runtime);
291		if (retval)
292			return -1;
293		retval = __osnoise_write_period(context, period);
294		if (retval)
295			return -1;
296	}
297
298	return 0;
299}
300
301/*
302 * osnoise_restore_runtime_period - restore the original runtime and period
303 */
304void osnoise_restore_runtime_period(struct osnoise_context *context)
305{
306	unsigned long long orig_runtime = context->orig_runtime_us;
307	unsigned long long orig_period = context->orig_period_us;
308	unsigned long long curr_runtime = context->runtime_us;
309	unsigned long long curr_period = context->period_us;
310	int retval;
311
312	if ((orig_runtime == OSNOISE_TIME_INIT_VAL) && (orig_period == OSNOISE_TIME_INIT_VAL))
313		return;
314
315	if ((orig_period == curr_period) && (orig_runtime == curr_runtime))
316		goto out_done;
317
318	retval = osnoise_set_runtime_period(context, orig_runtime, orig_period);
319	if (retval)
320		err_msg("Could not restore original osnoise runtime/period\n");
321
322out_done:
323	context->runtime_us = OSNOISE_TIME_INIT_VAL;
324	context->period_us = OSNOISE_TIME_INIT_VAL;
325}
326
327/*
328 * osnoise_put_runtime_period - restore original values and cleanup data
329 */
330void osnoise_put_runtime_period(struct osnoise_context *context)
331{
332	osnoise_restore_runtime_period(context);
333
334	if (context->orig_runtime_us != OSNOISE_TIME_INIT_VAL)
335		context->orig_runtime_us = OSNOISE_TIME_INIT_VAL;
336
337	if (context->orig_period_us != OSNOISE_TIME_INIT_VAL)
338		context->orig_period_us = OSNOISE_TIME_INIT_VAL;
339}
340
341/*
342 * osnoise_get_timerlat_period_us - read and save the original "timerlat_period_us"
343 */
344static long long
345osnoise_get_timerlat_period_us(struct osnoise_context *context)
346{
347	long long timerlat_period_us;
348
349	if (context->timerlat_period_us != OSNOISE_TIME_INIT_VAL)
350		return context->timerlat_period_us;
351
352	if (context->orig_timerlat_period_us != OSNOISE_TIME_INIT_VAL)
353		return context->orig_timerlat_period_us;
354
355	timerlat_period_us = osnoise_read_ll_config("osnoise/timerlat_period_us");
356	if (timerlat_period_us < 0)
357		goto out_err;
358
359	context->orig_timerlat_period_us = timerlat_period_us;
360	return timerlat_period_us;
361
362out_err:
363	return OSNOISE_TIME_INIT_VAL;
364}
365
366/*
367 * osnoise_set_timerlat_period_us - set "timerlat_period_us"
368 */
369int osnoise_set_timerlat_period_us(struct osnoise_context *context, long long timerlat_period_us)
370{
371	long long curr_timerlat_period_us = osnoise_get_timerlat_period_us(context);
372	int retval;
373
374	if (curr_timerlat_period_us == OSNOISE_TIME_INIT_VAL)
375		return -1;
376
377	retval = osnoise_write_ll_config("osnoise/timerlat_period_us", timerlat_period_us);
378	if (retval < 0)
379		return -1;
380
381	context->timerlat_period_us = timerlat_period_us;
382
383	return 0;
384}
385
386/*
387 * osnoise_restore_timerlat_period_us - restore "timerlat_period_us"
388 */
389void osnoise_restore_timerlat_period_us(struct osnoise_context *context)
390{
391	int retval;
392
393	if (context->orig_timerlat_period_us == OSNOISE_TIME_INIT_VAL)
394		return;
395
396	if (context->orig_timerlat_period_us == context->timerlat_period_us)
397		goto out_done;
398
399	retval = osnoise_write_ll_config("osnoise/timerlat_period_us", context->orig_timerlat_period_us);
400	if (retval < 0)
401		err_msg("Could not restore original osnoise timerlat_period_us\n");
402
403out_done:
404	context->timerlat_period_us = OSNOISE_TIME_INIT_VAL;
405}
406
407/*
408 * osnoise_put_timerlat_period_us - restore original values and cleanup data
409 */
410void osnoise_put_timerlat_period_us(struct osnoise_context *context)
411{
412	osnoise_restore_timerlat_period_us(context);
413
414	if (context->orig_timerlat_period_us == OSNOISE_TIME_INIT_VAL)
415		return;
416
417	context->orig_timerlat_period_us = OSNOISE_TIME_INIT_VAL;
418}
419
420/*
421 * osnoise_get_stop_us - read and save the original "stop_tracing_us"
422 */
423static long long
424osnoise_get_stop_us(struct osnoise_context *context)
425{
426	long long stop_us;
427
428	if (context->stop_us != OSNOISE_OPTION_INIT_VAL)
429		return context->stop_us;
430
431	if (context->orig_stop_us != OSNOISE_OPTION_INIT_VAL)
432		return context->orig_stop_us;
433
434	stop_us = osnoise_read_ll_config("osnoise/stop_tracing_us");
435	if (stop_us < 0)
436		goto out_err;
437
438	context->orig_stop_us = stop_us;
439	return stop_us;
440
441out_err:
442	return OSNOISE_OPTION_INIT_VAL;
443}
444
445/*
446 * osnoise_set_stop_us - set "stop_tracing_us"
447 */
448int osnoise_set_stop_us(struct osnoise_context *context, long long stop_us)
449{
450	long long curr_stop_us = osnoise_get_stop_us(context);
451	int retval;
452
453	if (curr_stop_us == OSNOISE_OPTION_INIT_VAL)
454		return -1;
455
456	retval = osnoise_write_ll_config("osnoise/stop_tracing_us", stop_us);
457	if (retval < 0)
458		return -1;
459
460	context->stop_us = stop_us;
461
462	return 0;
463}
464
465/*
466 * osnoise_restore_stop_us - restore the original "stop_tracing_us"
467 */
468void osnoise_restore_stop_us(struct osnoise_context *context)
469{
470	int retval;
471
472	if (context->orig_stop_us == OSNOISE_OPTION_INIT_VAL)
473		return;
474
475	if (context->orig_stop_us == context->stop_us)
476		goto out_done;
477
478	retval = osnoise_write_ll_config("osnoise/stop_tracing_us", context->orig_stop_us);
479	if (retval < 0)
480		err_msg("Could not restore original osnoise stop_us\n");
481
482out_done:
483	context->stop_us = OSNOISE_OPTION_INIT_VAL;
484}
485
486/*
487 * osnoise_put_stop_us - restore original values and cleanup data
488 */
489void osnoise_put_stop_us(struct osnoise_context *context)
490{
491	osnoise_restore_stop_us(context);
492
493	if (context->orig_stop_us == OSNOISE_OPTION_INIT_VAL)
494		return;
495
496	context->orig_stop_us = OSNOISE_OPTION_INIT_VAL;
497}
498
499/*
500 * osnoise_get_stop_total_us - read and save the original "stop_tracing_total_us"
501 */
502static long long
503osnoise_get_stop_total_us(struct osnoise_context *context)
504{
505	long long stop_total_us;
506
507	if (context->stop_total_us != OSNOISE_OPTION_INIT_VAL)
508		return context->stop_total_us;
509
510	if (context->orig_stop_total_us != OSNOISE_OPTION_INIT_VAL)
511		return context->orig_stop_total_us;
512
513	stop_total_us = osnoise_read_ll_config("osnoise/stop_tracing_total_us");
514	if (stop_total_us < 0)
515		goto out_err;
516
517	context->orig_stop_total_us = stop_total_us;
518	return stop_total_us;
519
520out_err:
521	return OSNOISE_OPTION_INIT_VAL;
522}
523
524/*
525 * osnoise_set_stop_total_us - set "stop_tracing_total_us"
526 */
527int osnoise_set_stop_total_us(struct osnoise_context *context, long long stop_total_us)
528{
529	long long curr_stop_total_us = osnoise_get_stop_total_us(context);
530	int retval;
531
532	if (curr_stop_total_us == OSNOISE_OPTION_INIT_VAL)
533		return -1;
534
535	retval = osnoise_write_ll_config("osnoise/stop_tracing_total_us", stop_total_us);
536	if (retval < 0)
537		return -1;
538
539	context->stop_total_us = stop_total_us;
540
541	return 0;
542}
543
544/*
545 * osnoise_restore_stop_total_us - restore the original "stop_tracing_total_us"
546 */
547void osnoise_restore_stop_total_us(struct osnoise_context *context)
548{
549	int retval;
550
551	if (context->orig_stop_total_us == OSNOISE_OPTION_INIT_VAL)
552		return;
553
554	if (context->orig_stop_total_us == context->stop_total_us)
555		goto out_done;
556
557	retval = osnoise_write_ll_config("osnoise/stop_tracing_total_us",
558			context->orig_stop_total_us);
559	if (retval < 0)
560		err_msg("Could not restore original osnoise stop_total_us\n");
561
562out_done:
563	context->stop_total_us = OSNOISE_OPTION_INIT_VAL;
564}
565
566/*
567 * osnoise_put_stop_total_us - restore original values and cleanup data
568 */
569void osnoise_put_stop_total_us(struct osnoise_context *context)
570{
571	osnoise_restore_stop_total_us(context);
572
573	if (context->orig_stop_total_us == OSNOISE_OPTION_INIT_VAL)
574		return;
575
576	context->orig_stop_total_us = OSNOISE_OPTION_INIT_VAL;
577}
578
579/*
580 * osnoise_get_print_stack - read and save the original "print_stack"
581 */
582static long long
583osnoise_get_print_stack(struct osnoise_context *context)
584{
585	long long print_stack;
586
587	if (context->print_stack != OSNOISE_OPTION_INIT_VAL)
588		return context->print_stack;
589
590	if (context->orig_print_stack != OSNOISE_OPTION_INIT_VAL)
591		return context->orig_print_stack;
592
593	print_stack = osnoise_read_ll_config("osnoise/print_stack");
594	if (print_stack < 0)
595		goto out_err;
596
597	context->orig_print_stack = print_stack;
598	return print_stack;
599
600out_err:
601	return OSNOISE_OPTION_INIT_VAL;
602}
603
604/*
605 * osnoise_set_print_stack - set "print_stack"
606 */
607int osnoise_set_print_stack(struct osnoise_context *context, long long print_stack)
608{
609	long long curr_print_stack = osnoise_get_print_stack(context);
610	int retval;
611
612	if (curr_print_stack == OSNOISE_OPTION_INIT_VAL)
613		return -1;
614
615	retval = osnoise_write_ll_config("osnoise/print_stack", print_stack);
616	if (retval < 0)
617		return -1;
618
619	context->print_stack = print_stack;
620
621	return 0;
622}
623
624/*
625 * osnoise_restore_print_stack - restore the original "print_stack"
626 */
627void osnoise_restore_print_stack(struct osnoise_context *context)
628{
629	int retval;
630
631	if (context->orig_print_stack == OSNOISE_OPTION_INIT_VAL)
632		return;
633
634	if (context->orig_print_stack == context->print_stack)
635		goto out_done;
636
637	retval = osnoise_write_ll_config("osnoise/print_stack", context->orig_print_stack);
638	if (retval < 0)
639		err_msg("Could not restore original osnoise print_stack\n");
640
641out_done:
642	context->print_stack = OSNOISE_OPTION_INIT_VAL;
643}
644
645/*
646 * osnoise_put_print_stack - restore original values and cleanup data
647 */
648void osnoise_put_print_stack(struct osnoise_context *context)
649{
650	osnoise_restore_print_stack(context);
651
652	if (context->orig_print_stack == OSNOISE_OPTION_INIT_VAL)
653		return;
654
655	context->orig_print_stack = OSNOISE_OPTION_INIT_VAL;
656}
657
658/*
659 * osnoise_get_tracing_thresh - read and save the original "tracing_thresh"
660 */
661static long long
662osnoise_get_tracing_thresh(struct osnoise_context *context)
663{
664	long long tracing_thresh;
665
666	if (context->tracing_thresh != OSNOISE_OPTION_INIT_VAL)
667		return context->tracing_thresh;
668
669	if (context->orig_tracing_thresh != OSNOISE_OPTION_INIT_VAL)
670		return context->orig_tracing_thresh;
671
672	tracing_thresh = osnoise_read_ll_config("tracing_thresh");
673	if (tracing_thresh < 0)
674		goto out_err;
675
676	context->orig_tracing_thresh = tracing_thresh;
677	return tracing_thresh;
678
679out_err:
680	return OSNOISE_OPTION_INIT_VAL;
681}
682
683/*
684 * osnoise_set_tracing_thresh - set "tracing_thresh"
685 */
686int osnoise_set_tracing_thresh(struct osnoise_context *context, long long tracing_thresh)
687{
688	long long curr_tracing_thresh = osnoise_get_tracing_thresh(context);
689	int retval;
690
691	if (curr_tracing_thresh == OSNOISE_OPTION_INIT_VAL)
692		return -1;
693
694	retval = osnoise_write_ll_config("tracing_thresh", tracing_thresh);
695	if (retval < 0)
696		return -1;
697
698	context->tracing_thresh = tracing_thresh;
699
700	return 0;
701}
702
703/*
704 * osnoise_restore_tracing_thresh - restore the original "tracing_thresh"
705 */
706void osnoise_restore_tracing_thresh(struct osnoise_context *context)
707{
708	int retval;
709
710	if (context->orig_tracing_thresh == OSNOISE_OPTION_INIT_VAL)
711		return;
712
713	if (context->orig_tracing_thresh == context->tracing_thresh)
714		goto out_done;
715
716	retval = osnoise_write_ll_config("tracing_thresh", context->orig_tracing_thresh);
717	if (retval < 0)
718		err_msg("Could not restore original tracing_thresh\n");
719
720out_done:
721	context->tracing_thresh = OSNOISE_OPTION_INIT_VAL;
722}
723
724/*
725 * osnoise_put_tracing_thresh - restore original values and cleanup data
726 */
727void osnoise_put_tracing_thresh(struct osnoise_context *context)
728{
729	osnoise_restore_tracing_thresh(context);
730
731	if (context->orig_tracing_thresh == OSNOISE_OPTION_INIT_VAL)
732		return;
733
734	context->orig_tracing_thresh = OSNOISE_OPTION_INIT_VAL;
735}
736
737/*
738 * enable_osnoise - enable osnoise tracer in the trace_instance
739 */
740int enable_osnoise(struct trace_instance *trace)
741{
742	return enable_tracer_by_name(trace->inst, "osnoise");
743}
744
745/*
746 * enable_timerlat - enable timerlat tracer in the trace_instance
747 */
748int enable_timerlat(struct trace_instance *trace)
749{
750	return enable_tracer_by_name(trace->inst, "timerlat");
751}
752
753enum {
754	FLAG_CONTEXT_NEWLY_CREATED	= (1 << 0),
755	FLAG_CONTEXT_DELETED		= (1 << 1),
756};
757
758/*
759 * osnoise_get_context - increase the usage of a context and return it
760 */
761int osnoise_get_context(struct osnoise_context *context)
762{
763	int ret;
764
765	if (context->flags & FLAG_CONTEXT_DELETED) {
766		ret = -1;
767	} else {
768		context->ref++;
769		ret = 0;
770	}
771
772	return ret;
773}
774
775/*
776 * osnoise_context_alloc - alloc an osnoise_context
777 *
778 * The osnoise context contains the information of the "osnoise/" configs.
779 * It is used to set and restore the config.
780 */
781struct osnoise_context *osnoise_context_alloc(void)
782{
783	struct osnoise_context *context;
784
785	context = calloc(1, sizeof(*context));
786	if (!context)
787		return NULL;
788
789	context->orig_stop_us		= OSNOISE_OPTION_INIT_VAL;
790	context->stop_us		= OSNOISE_OPTION_INIT_VAL;
791
792	context->orig_stop_total_us	= OSNOISE_OPTION_INIT_VAL;
793	context->stop_total_us		= OSNOISE_OPTION_INIT_VAL;
794
795	context->orig_print_stack	= OSNOISE_OPTION_INIT_VAL;
796	context->print_stack		= OSNOISE_OPTION_INIT_VAL;
797
798	context->orig_tracing_thresh	= OSNOISE_OPTION_INIT_VAL;
799	context->tracing_thresh		= OSNOISE_OPTION_INIT_VAL;
800
801	osnoise_get_context(context);
802
803	return context;
804}
805
806/*
807 * osnoise_put_context - put the osnoise_put_context
808 *
809 * If there is no other user for the context, the original data
810 * is restored.
811 */
812void osnoise_put_context(struct osnoise_context *context)
813{
814	if (--context->ref < 1)
815		context->flags |= FLAG_CONTEXT_DELETED;
816
817	if (!(context->flags & FLAG_CONTEXT_DELETED))
818		return;
819
820	osnoise_put_cpus(context);
821	osnoise_put_runtime_period(context);
822	osnoise_put_stop_us(context);
823	osnoise_put_stop_total_us(context);
824	osnoise_put_timerlat_period_us(context);
825	osnoise_put_print_stack(context);
826	osnoise_put_tracing_thresh(context);
827
828	free(context);
829}
830
831/*
832 * osnoise_destroy_tool - disable trace, restore configs and free data
833 */
834void osnoise_destroy_tool(struct osnoise_tool *top)
835{
836	if (!top)
837		return;
838
839	trace_instance_destroy(&top->trace);
840
841	if (top->context)
842		osnoise_put_context(top->context);
843
844	free(top);
845}
846
847/*
848 * osnoise_init_tool - init an osnoise tool
849 *
850 * It allocs data, create a context to store data and
851 * creates a new trace instance for the tool.
852 */
853struct osnoise_tool *osnoise_init_tool(char *tool_name)
854{
855	struct osnoise_tool *top;
856	int retval;
857
858	top = calloc(1, sizeof(*top));
859	if (!top)
860		return NULL;
861
862	top->context = osnoise_context_alloc();
863	if (!top->context)
864		goto out_err;
865
866	retval = trace_instance_init(&top->trace, tool_name);
867	if (retval)
868		goto out_err;
869
870	return top;
871out_err:
872	osnoise_destroy_tool(top);
873	return NULL;
874}
875
876/*
877 * osnoise_init_trace_tool - init a tracer instance to trace osnoise events
878 */
879struct osnoise_tool *osnoise_init_trace_tool(char *tracer)
880{
881	struct osnoise_tool *trace;
882	int retval;
883
884	trace = osnoise_init_tool("osnoise_trace");
885	if (!trace)
886		return NULL;
887
888	retval = tracefs_event_enable(trace->trace.inst, "osnoise", NULL);
889	if (retval < 0 && !errno) {
890		err_msg("Could not find osnoise events\n");
891		goto out_err;
892	}
893
894	retval = enable_tracer_by_name(trace->trace.inst, tracer);
895	if (retval) {
896		err_msg("Could not enable %s tracer for tracing\n", tracer);
897		goto out_err;
898	}
899
900	return trace;
901out_err:
902	osnoise_destroy_tool(trace);
903	return NULL;
904}
905
906static void osnoise_usage(int err)
907{
908	int i;
909
910	static const char *msg[] = {
911		"",
912		"osnoise version " VERSION,
913		"",
914		"  usage: [rtla] osnoise [MODE] ...",
915		"",
916		"  modes:",
917		"     top   - prints the summary from osnoise tracer",
918		"     hist  - prints a histogram of osnoise samples",
919		"",
920		"if no MODE is given, the top mode is called, passing the arguments",
921		NULL,
922	};
923
924	for (i = 0; msg[i]; i++)
925		fprintf(stderr, "%s\n", msg[i]);
926	exit(err);
927}
928
929int osnoise_main(int argc, char *argv[])
930{
931	if (argc == 0)
932		goto usage;
933
934	/*
935	 * if osnoise was called without any argument, run the
936	 * default cmdline.
937	 */
938	if (argc == 1) {
939		osnoise_top_main(argc, argv);
940		exit(0);
941	}
942
943	if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0)) {
944		osnoise_usage(0);
945	} else if (strncmp(argv[1], "-", 1) == 0) {
946		/* the user skipped the tool, call the default one */
947		osnoise_top_main(argc, argv);
948		exit(0);
949	} else if (strcmp(argv[1], "top") == 0) {
950		osnoise_top_main(argc-1, &argv[1]);
951		exit(0);
952	} else if (strcmp(argv[1], "hist") == 0) {
953		osnoise_hist_main(argc-1, &argv[1]);
954		exit(0);
955	}
956
957usage:
958	osnoise_usage(1);
959	exit(1);
960}