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1/* Include in trace.c */
2
3#include <linux/stringify.h>
4#include <linux/kthread.h>
5#include <linux/delay.h>
6#include <linux/slab.h>
7
8static inline int trace_valid_entry(struct trace_entry *entry)
9{
10 switch (entry->type) {
11 case TRACE_FN:
12 case TRACE_CTX:
13 case TRACE_WAKE:
14 case TRACE_STACK:
15 case TRACE_PRINT:
16 case TRACE_BRANCH:
17 case TRACE_GRAPH_ENT:
18 case TRACE_GRAPH_RET:
19 return 1;
20 }
21 return 0;
22}
23
24static int trace_test_buffer_cpu(struct trace_buffer *buf, int cpu)
25{
26 struct ring_buffer_event *event;
27 struct trace_entry *entry;
28 unsigned int loops = 0;
29
30 while ((event = ring_buffer_consume(buf->buffer, cpu, NULL, NULL))) {
31 entry = ring_buffer_event_data(event);
32
33 /*
34 * The ring buffer is a size of trace_buf_size, if
35 * we loop more than the size, there's something wrong
36 * with the ring buffer.
37 */
38 if (loops++ > trace_buf_size) {
39 printk(KERN_CONT ".. bad ring buffer ");
40 goto failed;
41 }
42 if (!trace_valid_entry(entry)) {
43 printk(KERN_CONT ".. invalid entry %d ",
44 entry->type);
45 goto failed;
46 }
47 }
48 return 0;
49
50 failed:
51 /* disable tracing */
52 tracing_disabled = 1;
53 printk(KERN_CONT ".. corrupted trace buffer .. ");
54 return -1;
55}
56
57/*
58 * Test the trace buffer to see if all the elements
59 * are still sane.
60 */
61static int trace_test_buffer(struct trace_buffer *buf, unsigned long *count)
62{
63 unsigned long flags, cnt = 0;
64 int cpu, ret = 0;
65
66 /* Don't allow flipping of max traces now */
67 local_irq_save(flags);
68 arch_spin_lock(&ftrace_max_lock);
69
70 cnt = ring_buffer_entries(buf->buffer);
71
72 /*
73 * The trace_test_buffer_cpu runs a while loop to consume all data.
74 * If the calling tracer is broken, and is constantly filling
75 * the buffer, this will run forever, and hard lock the box.
76 * We disable the ring buffer while we do this test to prevent
77 * a hard lock up.
78 */
79 tracing_off();
80 for_each_possible_cpu(cpu) {
81 ret = trace_test_buffer_cpu(buf, cpu);
82 if (ret)
83 break;
84 }
85 tracing_on();
86 arch_spin_unlock(&ftrace_max_lock);
87 local_irq_restore(flags);
88
89 if (count)
90 *count = cnt;
91
92 return ret;
93}
94
95static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
96{
97 printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
98 trace->name, init_ret);
99}
100#ifdef CONFIG_FUNCTION_TRACER
101
102#ifdef CONFIG_DYNAMIC_FTRACE
103
104static int trace_selftest_test_probe1_cnt;
105static void trace_selftest_test_probe1_func(unsigned long ip,
106 unsigned long pip,
107 struct ftrace_ops *op,
108 struct pt_regs *pt_regs)
109{
110 trace_selftest_test_probe1_cnt++;
111}
112
113static int trace_selftest_test_probe2_cnt;
114static void trace_selftest_test_probe2_func(unsigned long ip,
115 unsigned long pip,
116 struct ftrace_ops *op,
117 struct pt_regs *pt_regs)
118{
119 trace_selftest_test_probe2_cnt++;
120}
121
122static int trace_selftest_test_probe3_cnt;
123static void trace_selftest_test_probe3_func(unsigned long ip,
124 unsigned long pip,
125 struct ftrace_ops *op,
126 struct pt_regs *pt_regs)
127{
128 trace_selftest_test_probe3_cnt++;
129}
130
131static int trace_selftest_test_global_cnt;
132static void trace_selftest_test_global_func(unsigned long ip,
133 unsigned long pip,
134 struct ftrace_ops *op,
135 struct pt_regs *pt_regs)
136{
137 trace_selftest_test_global_cnt++;
138}
139
140static int trace_selftest_test_dyn_cnt;
141static void trace_selftest_test_dyn_func(unsigned long ip,
142 unsigned long pip,
143 struct ftrace_ops *op,
144 struct pt_regs *pt_regs)
145{
146 trace_selftest_test_dyn_cnt++;
147}
148
149static struct ftrace_ops test_probe1 = {
150 .func = trace_selftest_test_probe1_func,
151 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
152};
153
154static struct ftrace_ops test_probe2 = {
155 .func = trace_selftest_test_probe2_func,
156 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
157};
158
159static struct ftrace_ops test_probe3 = {
160 .func = trace_selftest_test_probe3_func,
161 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
162};
163
164static struct ftrace_ops test_global = {
165 .func = trace_selftest_test_global_func,
166 .flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
167};
168
169static void print_counts(void)
170{
171 printk("(%d %d %d %d %d) ",
172 trace_selftest_test_probe1_cnt,
173 trace_selftest_test_probe2_cnt,
174 trace_selftest_test_probe3_cnt,
175 trace_selftest_test_global_cnt,
176 trace_selftest_test_dyn_cnt);
177}
178
179static void reset_counts(void)
180{
181 trace_selftest_test_probe1_cnt = 0;
182 trace_selftest_test_probe2_cnt = 0;
183 trace_selftest_test_probe3_cnt = 0;
184 trace_selftest_test_global_cnt = 0;
185 trace_selftest_test_dyn_cnt = 0;
186}
187
188static int trace_selftest_ops(int cnt)
189{
190 int save_ftrace_enabled = ftrace_enabled;
191 struct ftrace_ops *dyn_ops;
192 char *func1_name;
193 char *func2_name;
194 int len1;
195 int len2;
196 int ret = -1;
197
198 printk(KERN_CONT "PASSED\n");
199 pr_info("Testing dynamic ftrace ops #%d: ", cnt);
200
201 ftrace_enabled = 1;
202 reset_counts();
203
204 /* Handle PPC64 '.' name */
205 func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
206 func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
207 len1 = strlen(func1_name);
208 len2 = strlen(func2_name);
209
210 /*
211 * Probe 1 will trace function 1.
212 * Probe 2 will trace function 2.
213 * Probe 3 will trace functions 1 and 2.
214 */
215 ftrace_set_filter(&test_probe1, func1_name, len1, 1);
216 ftrace_set_filter(&test_probe2, func2_name, len2, 1);
217 ftrace_set_filter(&test_probe3, func1_name, len1, 1);
218 ftrace_set_filter(&test_probe3, func2_name, len2, 0);
219
220 register_ftrace_function(&test_probe1);
221 register_ftrace_function(&test_probe2);
222 register_ftrace_function(&test_probe3);
223 register_ftrace_function(&test_global);
224
225 DYN_FTRACE_TEST_NAME();
226
227 print_counts();
228
229 if (trace_selftest_test_probe1_cnt != 1)
230 goto out;
231 if (trace_selftest_test_probe2_cnt != 0)
232 goto out;
233 if (trace_selftest_test_probe3_cnt != 1)
234 goto out;
235 if (trace_selftest_test_global_cnt == 0)
236 goto out;
237
238 DYN_FTRACE_TEST_NAME2();
239
240 print_counts();
241
242 if (trace_selftest_test_probe1_cnt != 1)
243 goto out;
244 if (trace_selftest_test_probe2_cnt != 1)
245 goto out;
246 if (trace_selftest_test_probe3_cnt != 2)
247 goto out;
248
249 /* Add a dynamic probe */
250 dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
251 if (!dyn_ops) {
252 printk("MEMORY ERROR ");
253 goto out;
254 }
255
256 dyn_ops->func = trace_selftest_test_dyn_func;
257
258 register_ftrace_function(dyn_ops);
259
260 trace_selftest_test_global_cnt = 0;
261
262 DYN_FTRACE_TEST_NAME();
263
264 print_counts();
265
266 if (trace_selftest_test_probe1_cnt != 2)
267 goto out_free;
268 if (trace_selftest_test_probe2_cnt != 1)
269 goto out_free;
270 if (trace_selftest_test_probe3_cnt != 3)
271 goto out_free;
272 if (trace_selftest_test_global_cnt == 0)
273 goto out;
274 if (trace_selftest_test_dyn_cnt == 0)
275 goto out_free;
276
277 DYN_FTRACE_TEST_NAME2();
278
279 print_counts();
280
281 if (trace_selftest_test_probe1_cnt != 2)
282 goto out_free;
283 if (trace_selftest_test_probe2_cnt != 2)
284 goto out_free;
285 if (trace_selftest_test_probe3_cnt != 4)
286 goto out_free;
287
288 ret = 0;
289 out_free:
290 unregister_ftrace_function(dyn_ops);
291 kfree(dyn_ops);
292
293 out:
294 /* Purposely unregister in the same order */
295 unregister_ftrace_function(&test_probe1);
296 unregister_ftrace_function(&test_probe2);
297 unregister_ftrace_function(&test_probe3);
298 unregister_ftrace_function(&test_global);
299
300 /* Make sure everything is off */
301 reset_counts();
302 DYN_FTRACE_TEST_NAME();
303 DYN_FTRACE_TEST_NAME();
304
305 if (trace_selftest_test_probe1_cnt ||
306 trace_selftest_test_probe2_cnt ||
307 trace_selftest_test_probe3_cnt ||
308 trace_selftest_test_global_cnt ||
309 trace_selftest_test_dyn_cnt)
310 ret = -1;
311
312 ftrace_enabled = save_ftrace_enabled;
313
314 return ret;
315}
316
317/* Test dynamic code modification and ftrace filters */
318int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
319 struct trace_array *tr,
320 int (*func)(void))
321{
322 int save_ftrace_enabled = ftrace_enabled;
323 unsigned long count;
324 char *func_name;
325 int ret;
326
327 /* The ftrace test PASSED */
328 printk(KERN_CONT "PASSED\n");
329 pr_info("Testing dynamic ftrace: ");
330
331 /* enable tracing, and record the filter function */
332 ftrace_enabled = 1;
333
334 /* passed in by parameter to fool gcc from optimizing */
335 func();
336
337 /*
338 * Some archs *cough*PowerPC*cough* add characters to the
339 * start of the function names. We simply put a '*' to
340 * accommodate them.
341 */
342 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
343
344 /* filter only on our function */
345 ftrace_set_global_filter(func_name, strlen(func_name), 1);
346
347 /* enable tracing */
348 ret = tracer_init(trace, tr);
349 if (ret) {
350 warn_failed_init_tracer(trace, ret);
351 goto out;
352 }
353
354 /* Sleep for a 1/10 of a second */
355 msleep(100);
356
357 /* we should have nothing in the buffer */
358 ret = trace_test_buffer(&tr->trace_buffer, &count);
359 if (ret)
360 goto out;
361
362 if (count) {
363 ret = -1;
364 printk(KERN_CONT ".. filter did not filter .. ");
365 goto out;
366 }
367
368 /* call our function again */
369 func();
370
371 /* sleep again */
372 msleep(100);
373
374 /* stop the tracing. */
375 tracing_stop();
376 ftrace_enabled = 0;
377
378 /* check the trace buffer */
379 ret = trace_test_buffer(&tr->trace_buffer, &count);
380 tracing_start();
381
382 /* we should only have one item */
383 if (!ret && count != 1) {
384 trace->reset(tr);
385 printk(KERN_CONT ".. filter failed count=%ld ..", count);
386 ret = -1;
387 goto out;
388 }
389
390 /* Test the ops with global tracing running */
391 ret = trace_selftest_ops(1);
392 trace->reset(tr);
393
394 out:
395 ftrace_enabled = save_ftrace_enabled;
396
397 /* Enable tracing on all functions again */
398 ftrace_set_global_filter(NULL, 0, 1);
399
400 /* Test the ops with global tracing off */
401 if (!ret)
402 ret = trace_selftest_ops(2);
403
404 return ret;
405}
406
407static int trace_selftest_recursion_cnt;
408static void trace_selftest_test_recursion_func(unsigned long ip,
409 unsigned long pip,
410 struct ftrace_ops *op,
411 struct pt_regs *pt_regs)
412{
413 /*
414 * This function is registered without the recursion safe flag.
415 * The ftrace infrastructure should provide the recursion
416 * protection. If not, this will crash the kernel!
417 */
418 if (trace_selftest_recursion_cnt++ > 10)
419 return;
420 DYN_FTRACE_TEST_NAME();
421}
422
423static void trace_selftest_test_recursion_safe_func(unsigned long ip,
424 unsigned long pip,
425 struct ftrace_ops *op,
426 struct pt_regs *pt_regs)
427{
428 /*
429 * We said we would provide our own recursion. By calling
430 * this function again, we should recurse back into this function
431 * and count again. But this only happens if the arch supports
432 * all of ftrace features and nothing else is using the function
433 * tracing utility.
434 */
435 if (trace_selftest_recursion_cnt++)
436 return;
437 DYN_FTRACE_TEST_NAME();
438}
439
440static struct ftrace_ops test_rec_probe = {
441 .func = trace_selftest_test_recursion_func,
442};
443
444static struct ftrace_ops test_recsafe_probe = {
445 .func = trace_selftest_test_recursion_safe_func,
446 .flags = FTRACE_OPS_FL_RECURSION_SAFE,
447};
448
449static int
450trace_selftest_function_recursion(void)
451{
452 int save_ftrace_enabled = ftrace_enabled;
453 char *func_name;
454 int len;
455 int ret;
456
457 /* The previous test PASSED */
458 pr_cont("PASSED\n");
459 pr_info("Testing ftrace recursion: ");
460
461
462 /* enable tracing, and record the filter function */
463 ftrace_enabled = 1;
464
465 /* Handle PPC64 '.' name */
466 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
467 len = strlen(func_name);
468
469 ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
470 if (ret) {
471 pr_cont("*Could not set filter* ");
472 goto out;
473 }
474
475 ret = register_ftrace_function(&test_rec_probe);
476 if (ret) {
477 pr_cont("*could not register callback* ");
478 goto out;
479 }
480
481 DYN_FTRACE_TEST_NAME();
482
483 unregister_ftrace_function(&test_rec_probe);
484
485 ret = -1;
486 if (trace_selftest_recursion_cnt != 1) {
487 pr_cont("*callback not called once (%d)* ",
488 trace_selftest_recursion_cnt);
489 goto out;
490 }
491
492 trace_selftest_recursion_cnt = 1;
493
494 pr_cont("PASSED\n");
495 pr_info("Testing ftrace recursion safe: ");
496
497 ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
498 if (ret) {
499 pr_cont("*Could not set filter* ");
500 goto out;
501 }
502
503 ret = register_ftrace_function(&test_recsafe_probe);
504 if (ret) {
505 pr_cont("*could not register callback* ");
506 goto out;
507 }
508
509 DYN_FTRACE_TEST_NAME();
510
511 unregister_ftrace_function(&test_recsafe_probe);
512
513 ret = -1;
514 if (trace_selftest_recursion_cnt != 2) {
515 pr_cont("*callback not called expected 2 times (%d)* ",
516 trace_selftest_recursion_cnt);
517 goto out;
518 }
519
520 ret = 0;
521out:
522 ftrace_enabled = save_ftrace_enabled;
523
524 return ret;
525}
526#else
527# define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
528# define trace_selftest_function_recursion() ({ 0; })
529#endif /* CONFIG_DYNAMIC_FTRACE */
530
531static enum {
532 TRACE_SELFTEST_REGS_START,
533 TRACE_SELFTEST_REGS_FOUND,
534 TRACE_SELFTEST_REGS_NOT_FOUND,
535} trace_selftest_regs_stat;
536
537static void trace_selftest_test_regs_func(unsigned long ip,
538 unsigned long pip,
539 struct ftrace_ops *op,
540 struct pt_regs *pt_regs)
541{
542 if (pt_regs)
543 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
544 else
545 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
546}
547
548static struct ftrace_ops test_regs_probe = {
549 .func = trace_selftest_test_regs_func,
550 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS,
551};
552
553static int
554trace_selftest_function_regs(void)
555{
556 int save_ftrace_enabled = ftrace_enabled;
557 char *func_name;
558 int len;
559 int ret;
560 int supported = 0;
561
562#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
563 supported = 1;
564#endif
565
566 /* The previous test PASSED */
567 pr_cont("PASSED\n");
568 pr_info("Testing ftrace regs%s: ",
569 !supported ? "(no arch support)" : "");
570
571 /* enable tracing, and record the filter function */
572 ftrace_enabled = 1;
573
574 /* Handle PPC64 '.' name */
575 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
576 len = strlen(func_name);
577
578 ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
579 /*
580 * If DYNAMIC_FTRACE is not set, then we just trace all functions.
581 * This test really doesn't care.
582 */
583 if (ret && ret != -ENODEV) {
584 pr_cont("*Could not set filter* ");
585 goto out;
586 }
587
588 ret = register_ftrace_function(&test_regs_probe);
589 /*
590 * Now if the arch does not support passing regs, then this should
591 * have failed.
592 */
593 if (!supported) {
594 if (!ret) {
595 pr_cont("*registered save-regs without arch support* ");
596 goto out;
597 }
598 test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
599 ret = register_ftrace_function(&test_regs_probe);
600 }
601 if (ret) {
602 pr_cont("*could not register callback* ");
603 goto out;
604 }
605
606
607 DYN_FTRACE_TEST_NAME();
608
609 unregister_ftrace_function(&test_regs_probe);
610
611 ret = -1;
612
613 switch (trace_selftest_regs_stat) {
614 case TRACE_SELFTEST_REGS_START:
615 pr_cont("*callback never called* ");
616 goto out;
617
618 case TRACE_SELFTEST_REGS_FOUND:
619 if (supported)
620 break;
621 pr_cont("*callback received regs without arch support* ");
622 goto out;
623
624 case TRACE_SELFTEST_REGS_NOT_FOUND:
625 if (!supported)
626 break;
627 pr_cont("*callback received NULL regs* ");
628 goto out;
629 }
630
631 ret = 0;
632out:
633 ftrace_enabled = save_ftrace_enabled;
634
635 return ret;
636}
637
638/*
639 * Simple verification test of ftrace function tracer.
640 * Enable ftrace, sleep 1/10 second, and then read the trace
641 * buffer to see if all is in order.
642 */
643__init int
644trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
645{
646 int save_ftrace_enabled = ftrace_enabled;
647 unsigned long count;
648 int ret;
649
650#ifdef CONFIG_DYNAMIC_FTRACE
651 if (ftrace_filter_param) {
652 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
653 return 0;
654 }
655#endif
656
657 /* make sure msleep has been recorded */
658 msleep(1);
659
660 /* start the tracing */
661 ftrace_enabled = 1;
662
663 ret = tracer_init(trace, tr);
664 if (ret) {
665 warn_failed_init_tracer(trace, ret);
666 goto out;
667 }
668
669 /* Sleep for a 1/10 of a second */
670 msleep(100);
671 /* stop the tracing. */
672 tracing_stop();
673 ftrace_enabled = 0;
674
675 /* check the trace buffer */
676 ret = trace_test_buffer(&tr->trace_buffer, &count);
677 trace->reset(tr);
678 tracing_start();
679
680 if (!ret && !count) {
681 printk(KERN_CONT ".. no entries found ..");
682 ret = -1;
683 goto out;
684 }
685
686 ret = trace_selftest_startup_dynamic_tracing(trace, tr,
687 DYN_FTRACE_TEST_NAME);
688 if (ret)
689 goto out;
690
691 ret = trace_selftest_function_recursion();
692 if (ret)
693 goto out;
694
695 ret = trace_selftest_function_regs();
696 out:
697 ftrace_enabled = save_ftrace_enabled;
698
699 /* kill ftrace totally if we failed */
700 if (ret)
701 ftrace_kill();
702
703 return ret;
704}
705#endif /* CONFIG_FUNCTION_TRACER */
706
707
708#ifdef CONFIG_FUNCTION_GRAPH_TRACER
709
710/* Maximum number of functions to trace before diagnosing a hang */
711#define GRAPH_MAX_FUNC_TEST 100000000
712
713static unsigned int graph_hang_thresh;
714
715/* Wrap the real function entry probe to avoid possible hanging */
716static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
717{
718 /* This is harmlessly racy, we want to approximately detect a hang */
719 if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
720 ftrace_graph_stop();
721 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
722 if (ftrace_dump_on_oops) {
723 ftrace_dump(DUMP_ALL);
724 /* ftrace_dump() disables tracing */
725 tracing_on();
726 }
727 return 0;
728 }
729
730 return trace_graph_entry(trace);
731}
732
733/*
734 * Pretty much the same than for the function tracer from which the selftest
735 * has been borrowed.
736 */
737__init int
738trace_selftest_startup_function_graph(struct tracer *trace,
739 struct trace_array *tr)
740{
741 int ret;
742 unsigned long count;
743
744#ifdef CONFIG_DYNAMIC_FTRACE
745 if (ftrace_filter_param) {
746 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
747 return 0;
748 }
749#endif
750
751 /*
752 * Simulate the init() callback but we attach a watchdog callback
753 * to detect and recover from possible hangs
754 */
755 tracing_reset_online_cpus(&tr->trace_buffer);
756 set_graph_array(tr);
757 ret = register_ftrace_graph(&trace_graph_return,
758 &trace_graph_entry_watchdog);
759 if (ret) {
760 warn_failed_init_tracer(trace, ret);
761 goto out;
762 }
763 tracing_start_cmdline_record();
764
765 /* Sleep for a 1/10 of a second */
766 msleep(100);
767
768 /* Have we just recovered from a hang? */
769 if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
770 tracing_selftest_disabled = true;
771 ret = -1;
772 goto out;
773 }
774
775 tracing_stop();
776
777 /* check the trace buffer */
778 ret = trace_test_buffer(&tr->trace_buffer, &count);
779
780 trace->reset(tr);
781 tracing_start();
782
783 if (!ret && !count) {
784 printk(KERN_CONT ".. no entries found ..");
785 ret = -1;
786 goto out;
787 }
788
789 /* Don't test dynamic tracing, the function tracer already did */
790
791out:
792 /* Stop it if we failed */
793 if (ret)
794 ftrace_graph_stop();
795
796 return ret;
797}
798#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
799
800
801#ifdef CONFIG_IRQSOFF_TRACER
802int
803trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
804{
805 unsigned long save_max = tracing_max_latency;
806 unsigned long count;
807 int ret;
808
809 /* start the tracing */
810 ret = tracer_init(trace, tr);
811 if (ret) {
812 warn_failed_init_tracer(trace, ret);
813 return ret;
814 }
815
816 /* reset the max latency */
817 tracing_max_latency = 0;
818 /* disable interrupts for a bit */
819 local_irq_disable();
820 udelay(100);
821 local_irq_enable();
822
823 /*
824 * Stop the tracer to avoid a warning subsequent
825 * to buffer flipping failure because tracing_stop()
826 * disables the tr and max buffers, making flipping impossible
827 * in case of parallels max irqs off latencies.
828 */
829 trace->stop(tr);
830 /* stop the tracing. */
831 tracing_stop();
832 /* check both trace buffers */
833 ret = trace_test_buffer(&tr->trace_buffer, NULL);
834 if (!ret)
835 ret = trace_test_buffer(&tr->max_buffer, &count);
836 trace->reset(tr);
837 tracing_start();
838
839 if (!ret && !count) {
840 printk(KERN_CONT ".. no entries found ..");
841 ret = -1;
842 }
843
844 tracing_max_latency = save_max;
845
846 return ret;
847}
848#endif /* CONFIG_IRQSOFF_TRACER */
849
850#ifdef CONFIG_PREEMPT_TRACER
851int
852trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
853{
854 unsigned long save_max = tracing_max_latency;
855 unsigned long count;
856 int ret;
857
858 /*
859 * Now that the big kernel lock is no longer preemptable,
860 * and this is called with the BKL held, it will always
861 * fail. If preemption is already disabled, simply
862 * pass the test. When the BKL is removed, or becomes
863 * preemptible again, we will once again test this,
864 * so keep it in.
865 */
866 if (preempt_count()) {
867 printk(KERN_CONT "can not test ... force ");
868 return 0;
869 }
870
871 /* start the tracing */
872 ret = tracer_init(trace, tr);
873 if (ret) {
874 warn_failed_init_tracer(trace, ret);
875 return ret;
876 }
877
878 /* reset the max latency */
879 tracing_max_latency = 0;
880 /* disable preemption for a bit */
881 preempt_disable();
882 udelay(100);
883 preempt_enable();
884
885 /*
886 * Stop the tracer to avoid a warning subsequent
887 * to buffer flipping failure because tracing_stop()
888 * disables the tr and max buffers, making flipping impossible
889 * in case of parallels max preempt off latencies.
890 */
891 trace->stop(tr);
892 /* stop the tracing. */
893 tracing_stop();
894 /* check both trace buffers */
895 ret = trace_test_buffer(&tr->trace_buffer, NULL);
896 if (!ret)
897 ret = trace_test_buffer(&tr->max_buffer, &count);
898 trace->reset(tr);
899 tracing_start();
900
901 if (!ret && !count) {
902 printk(KERN_CONT ".. no entries found ..");
903 ret = -1;
904 }
905
906 tracing_max_latency = save_max;
907
908 return ret;
909}
910#endif /* CONFIG_PREEMPT_TRACER */
911
912#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
913int
914trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
915{
916 unsigned long save_max = tracing_max_latency;
917 unsigned long count;
918 int ret;
919
920 /*
921 * Now that the big kernel lock is no longer preemptable,
922 * and this is called with the BKL held, it will always
923 * fail. If preemption is already disabled, simply
924 * pass the test. When the BKL is removed, or becomes
925 * preemptible again, we will once again test this,
926 * so keep it in.
927 */
928 if (preempt_count()) {
929 printk(KERN_CONT "can not test ... force ");
930 return 0;
931 }
932
933 /* start the tracing */
934 ret = tracer_init(trace, tr);
935 if (ret) {
936 warn_failed_init_tracer(trace, ret);
937 goto out_no_start;
938 }
939
940 /* reset the max latency */
941 tracing_max_latency = 0;
942
943 /* disable preemption and interrupts for a bit */
944 preempt_disable();
945 local_irq_disable();
946 udelay(100);
947 preempt_enable();
948 /* reverse the order of preempt vs irqs */
949 local_irq_enable();
950
951 /*
952 * Stop the tracer to avoid a warning subsequent
953 * to buffer flipping failure because tracing_stop()
954 * disables the tr and max buffers, making flipping impossible
955 * in case of parallels max irqs/preempt off latencies.
956 */
957 trace->stop(tr);
958 /* stop the tracing. */
959 tracing_stop();
960 /* check both trace buffers */
961 ret = trace_test_buffer(&tr->trace_buffer, NULL);
962 if (ret)
963 goto out;
964
965 ret = trace_test_buffer(&tr->max_buffer, &count);
966 if (ret)
967 goto out;
968
969 if (!ret && !count) {
970 printk(KERN_CONT ".. no entries found ..");
971 ret = -1;
972 goto out;
973 }
974
975 /* do the test by disabling interrupts first this time */
976 tracing_max_latency = 0;
977 tracing_start();
978 trace->start(tr);
979
980 preempt_disable();
981 local_irq_disable();
982 udelay(100);
983 preempt_enable();
984 /* reverse the order of preempt vs irqs */
985 local_irq_enable();
986
987 trace->stop(tr);
988 /* stop the tracing. */
989 tracing_stop();
990 /* check both trace buffers */
991 ret = trace_test_buffer(&tr->trace_buffer, NULL);
992 if (ret)
993 goto out;
994
995 ret = trace_test_buffer(&tr->max_buffer, &count);
996
997 if (!ret && !count) {
998 printk(KERN_CONT ".. no entries found ..");
999 ret = -1;
1000 goto out;
1001 }
1002
1003out:
1004 tracing_start();
1005out_no_start:
1006 trace->reset(tr);
1007 tracing_max_latency = save_max;
1008
1009 return ret;
1010}
1011#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
1012
1013#ifdef CONFIG_NOP_TRACER
1014int
1015trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1016{
1017 /* What could possibly go wrong? */
1018 return 0;
1019}
1020#endif
1021
1022#ifdef CONFIG_SCHED_TRACER
1023static int trace_wakeup_test_thread(void *data)
1024{
1025 /* Make this a -deadline thread */
1026 static const struct sched_attr attr = {
1027 .sched_policy = SCHED_DEADLINE,
1028 .sched_runtime = 100000ULL,
1029 .sched_deadline = 10000000ULL,
1030 .sched_period = 10000000ULL
1031 };
1032 struct completion *x = data;
1033
1034 sched_setattr(current, &attr);
1035
1036 /* Make it know we have a new prio */
1037 complete(x);
1038
1039 /* now go to sleep and let the test wake us up */
1040 set_current_state(TASK_INTERRUPTIBLE);
1041 schedule();
1042
1043 complete(x);
1044
1045 /* we are awake, now wait to disappear */
1046 while (!kthread_should_stop()) {
1047 /*
1048 * This will likely be the system top priority
1049 * task, do short sleeps to let others run.
1050 */
1051 msleep(100);
1052 }
1053
1054 return 0;
1055}
1056
1057int
1058trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1059{
1060 unsigned long save_max = tracing_max_latency;
1061 struct task_struct *p;
1062 struct completion is_ready;
1063 unsigned long count;
1064 int ret;
1065
1066 init_completion(&is_ready);
1067
1068 /* create a -deadline thread */
1069 p = kthread_run(trace_wakeup_test_thread, &is_ready, "ftrace-test");
1070 if (IS_ERR(p)) {
1071 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1072 return -1;
1073 }
1074
1075 /* make sure the thread is running at -deadline policy */
1076 wait_for_completion(&is_ready);
1077
1078 /* start the tracing */
1079 ret = tracer_init(trace, tr);
1080 if (ret) {
1081 warn_failed_init_tracer(trace, ret);
1082 return ret;
1083 }
1084
1085 /* reset the max latency */
1086 tracing_max_latency = 0;
1087
1088 while (p->on_rq) {
1089 /*
1090 * Sleep to make sure the -deadline thread is asleep too.
1091 * On virtual machines we can't rely on timings,
1092 * but we want to make sure this test still works.
1093 */
1094 msleep(100);
1095 }
1096
1097 init_completion(&is_ready);
1098
1099 wake_up_process(p);
1100
1101 /* Wait for the task to wake up */
1102 wait_for_completion(&is_ready);
1103
1104 /* stop the tracing. */
1105 tracing_stop();
1106 /* check both trace buffers */
1107 ret = trace_test_buffer(&tr->trace_buffer, NULL);
1108 printk("ret = %d\n", ret);
1109 if (!ret)
1110 ret = trace_test_buffer(&tr->max_buffer, &count);
1111
1112
1113 trace->reset(tr);
1114 tracing_start();
1115
1116 tracing_max_latency = save_max;
1117
1118 /* kill the thread */
1119 kthread_stop(p);
1120
1121 if (!ret && !count) {
1122 printk(KERN_CONT ".. no entries found ..");
1123 ret = -1;
1124 }
1125
1126 return ret;
1127}
1128#endif /* CONFIG_SCHED_TRACER */
1129
1130#ifdef CONFIG_CONTEXT_SWITCH_TRACER
1131int
1132trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
1133{
1134 unsigned long count;
1135 int ret;
1136
1137 /* start the tracing */
1138 ret = tracer_init(trace, tr);
1139 if (ret) {
1140 warn_failed_init_tracer(trace, ret);
1141 return ret;
1142 }
1143
1144 /* Sleep for a 1/10 of a second */
1145 msleep(100);
1146 /* stop the tracing. */
1147 tracing_stop();
1148 /* check the trace buffer */
1149 ret = trace_test_buffer(&tr->trace_buffer, &count);
1150 trace->reset(tr);
1151 tracing_start();
1152
1153 if (!ret && !count) {
1154 printk(KERN_CONT ".. no entries found ..");
1155 ret = -1;
1156 }
1157
1158 return ret;
1159}
1160#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
1161
1162#ifdef CONFIG_BRANCH_TRACER
1163int
1164trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1165{
1166 unsigned long count;
1167 int ret;
1168
1169 /* start the tracing */
1170 ret = tracer_init(trace, tr);
1171 if (ret) {
1172 warn_failed_init_tracer(trace, ret);
1173 return ret;
1174 }
1175
1176 /* Sleep for a 1/10 of a second */
1177 msleep(100);
1178 /* stop the tracing. */
1179 tracing_stop();
1180 /* check the trace buffer */
1181 ret = trace_test_buffer(&tr->trace_buffer, &count);
1182 trace->reset(tr);
1183 tracing_start();
1184
1185 if (!ret && !count) {
1186 printk(KERN_CONT ".. no entries found ..");
1187 ret = -1;
1188 }
1189
1190 return ret;
1191}
1192#endif /* CONFIG_BRANCH_TRACER */
1193
1// SPDX-License-Identifier: GPL-2.0
2/* Include in trace.c */
3
4#include <uapi/linux/sched/types.h>
5#include <linux/stringify.h>
6#include <linux/kthread.h>
7#include <linux/delay.h>
8#include <linux/slab.h>
9
10static inline int trace_valid_entry(struct trace_entry *entry)
11{
12 switch (entry->type) {
13 case TRACE_FN:
14 case TRACE_CTX:
15 case TRACE_WAKE:
16 case TRACE_STACK:
17 case TRACE_PRINT:
18 case TRACE_BRANCH:
19 case TRACE_GRAPH_ENT:
20 case TRACE_GRAPH_RET:
21 return 1;
22 }
23 return 0;
24}
25
26static int trace_test_buffer_cpu(struct array_buffer *buf, int cpu)
27{
28 struct ring_buffer_event *event;
29 struct trace_entry *entry;
30 unsigned int loops = 0;
31
32 while ((event = ring_buffer_consume(buf->buffer, cpu, NULL, NULL))) {
33 entry = ring_buffer_event_data(event);
34
35 /*
36 * The ring buffer is a size of trace_buf_size, if
37 * we loop more than the size, there's something wrong
38 * with the ring buffer.
39 */
40 if (loops++ > trace_buf_size) {
41 printk(KERN_CONT ".. bad ring buffer ");
42 goto failed;
43 }
44 if (!trace_valid_entry(entry)) {
45 printk(KERN_CONT ".. invalid entry %d ",
46 entry->type);
47 goto failed;
48 }
49 }
50 return 0;
51
52 failed:
53 /* disable tracing */
54 tracing_disabled = 1;
55 printk(KERN_CONT ".. corrupted trace buffer .. ");
56 return -1;
57}
58
59/*
60 * Test the trace buffer to see if all the elements
61 * are still sane.
62 */
63static int __maybe_unused trace_test_buffer(struct array_buffer *buf, unsigned long *count)
64{
65 unsigned long flags, cnt = 0;
66 int cpu, ret = 0;
67
68 /* Don't allow flipping of max traces now */
69 local_irq_save(flags);
70 arch_spin_lock(&buf->tr->max_lock);
71
72 cnt = ring_buffer_entries(buf->buffer);
73
74 /*
75 * The trace_test_buffer_cpu runs a while loop to consume all data.
76 * If the calling tracer is broken, and is constantly filling
77 * the buffer, this will run forever, and hard lock the box.
78 * We disable the ring buffer while we do this test to prevent
79 * a hard lock up.
80 */
81 tracing_off();
82 for_each_possible_cpu(cpu) {
83 ret = trace_test_buffer_cpu(buf, cpu);
84 if (ret)
85 break;
86 }
87 tracing_on();
88 arch_spin_unlock(&buf->tr->max_lock);
89 local_irq_restore(flags);
90
91 if (count)
92 *count = cnt;
93
94 return ret;
95}
96
97static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
98{
99 printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
100 trace->name, init_ret);
101}
102#ifdef CONFIG_FUNCTION_TRACER
103
104#ifdef CONFIG_DYNAMIC_FTRACE
105
106static int trace_selftest_test_probe1_cnt;
107static void trace_selftest_test_probe1_func(unsigned long ip,
108 unsigned long pip,
109 struct ftrace_ops *op,
110 struct ftrace_regs *fregs)
111{
112 trace_selftest_test_probe1_cnt++;
113}
114
115static int trace_selftest_test_probe2_cnt;
116static void trace_selftest_test_probe2_func(unsigned long ip,
117 unsigned long pip,
118 struct ftrace_ops *op,
119 struct ftrace_regs *fregs)
120{
121 trace_selftest_test_probe2_cnt++;
122}
123
124static int trace_selftest_test_probe3_cnt;
125static void trace_selftest_test_probe3_func(unsigned long ip,
126 unsigned long pip,
127 struct ftrace_ops *op,
128 struct ftrace_regs *fregs)
129{
130 trace_selftest_test_probe3_cnt++;
131}
132
133static int trace_selftest_test_global_cnt;
134static void trace_selftest_test_global_func(unsigned long ip,
135 unsigned long pip,
136 struct ftrace_ops *op,
137 struct ftrace_regs *fregs)
138{
139 trace_selftest_test_global_cnt++;
140}
141
142static int trace_selftest_test_dyn_cnt;
143static void trace_selftest_test_dyn_func(unsigned long ip,
144 unsigned long pip,
145 struct ftrace_ops *op,
146 struct ftrace_regs *fregs)
147{
148 trace_selftest_test_dyn_cnt++;
149}
150
151static struct ftrace_ops test_probe1 = {
152 .func = trace_selftest_test_probe1_func,
153};
154
155static struct ftrace_ops test_probe2 = {
156 .func = trace_selftest_test_probe2_func,
157};
158
159static struct ftrace_ops test_probe3 = {
160 .func = trace_selftest_test_probe3_func,
161};
162
163static void print_counts(void)
164{
165 printk("(%d %d %d %d %d) ",
166 trace_selftest_test_probe1_cnt,
167 trace_selftest_test_probe2_cnt,
168 trace_selftest_test_probe3_cnt,
169 trace_selftest_test_global_cnt,
170 trace_selftest_test_dyn_cnt);
171}
172
173static void reset_counts(void)
174{
175 trace_selftest_test_probe1_cnt = 0;
176 trace_selftest_test_probe2_cnt = 0;
177 trace_selftest_test_probe3_cnt = 0;
178 trace_selftest_test_global_cnt = 0;
179 trace_selftest_test_dyn_cnt = 0;
180}
181
182static int trace_selftest_ops(struct trace_array *tr, int cnt)
183{
184 int save_ftrace_enabled = ftrace_enabled;
185 struct ftrace_ops *dyn_ops;
186 char *func1_name;
187 char *func2_name;
188 int len1;
189 int len2;
190 int ret = -1;
191
192 printk(KERN_CONT "PASSED\n");
193 pr_info("Testing dynamic ftrace ops #%d: ", cnt);
194
195 ftrace_enabled = 1;
196 reset_counts();
197
198 /* Handle PPC64 '.' name */
199 func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
200 func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
201 len1 = strlen(func1_name);
202 len2 = strlen(func2_name);
203
204 /*
205 * Probe 1 will trace function 1.
206 * Probe 2 will trace function 2.
207 * Probe 3 will trace functions 1 and 2.
208 */
209 ftrace_set_filter(&test_probe1, func1_name, len1, 1);
210 ftrace_set_filter(&test_probe2, func2_name, len2, 1);
211 ftrace_set_filter(&test_probe3, func1_name, len1, 1);
212 ftrace_set_filter(&test_probe3, func2_name, len2, 0);
213
214 register_ftrace_function(&test_probe1);
215 register_ftrace_function(&test_probe2);
216 register_ftrace_function(&test_probe3);
217 /* First time we are running with main function */
218 if (cnt > 1) {
219 ftrace_init_array_ops(tr, trace_selftest_test_global_func);
220 register_ftrace_function(tr->ops);
221 }
222
223 DYN_FTRACE_TEST_NAME();
224
225 print_counts();
226
227 if (trace_selftest_test_probe1_cnt != 1)
228 goto out;
229 if (trace_selftest_test_probe2_cnt != 0)
230 goto out;
231 if (trace_selftest_test_probe3_cnt != 1)
232 goto out;
233 if (cnt > 1) {
234 if (trace_selftest_test_global_cnt == 0)
235 goto out;
236 }
237
238 DYN_FTRACE_TEST_NAME2();
239
240 print_counts();
241
242 if (trace_selftest_test_probe1_cnt != 1)
243 goto out;
244 if (trace_selftest_test_probe2_cnt != 1)
245 goto out;
246 if (trace_selftest_test_probe3_cnt != 2)
247 goto out;
248
249 /* Add a dynamic probe */
250 dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
251 if (!dyn_ops) {
252 printk("MEMORY ERROR ");
253 goto out;
254 }
255
256 dyn_ops->func = trace_selftest_test_dyn_func;
257
258 register_ftrace_function(dyn_ops);
259
260 trace_selftest_test_global_cnt = 0;
261
262 DYN_FTRACE_TEST_NAME();
263
264 print_counts();
265
266 if (trace_selftest_test_probe1_cnt != 2)
267 goto out_free;
268 if (trace_selftest_test_probe2_cnt != 1)
269 goto out_free;
270 if (trace_selftest_test_probe3_cnt != 3)
271 goto out_free;
272 if (cnt > 1) {
273 if (trace_selftest_test_global_cnt == 0)
274 goto out_free;
275 }
276 if (trace_selftest_test_dyn_cnt == 0)
277 goto out_free;
278
279 DYN_FTRACE_TEST_NAME2();
280
281 print_counts();
282
283 if (trace_selftest_test_probe1_cnt != 2)
284 goto out_free;
285 if (trace_selftest_test_probe2_cnt != 2)
286 goto out_free;
287 if (trace_selftest_test_probe3_cnt != 4)
288 goto out_free;
289
290 ret = 0;
291 out_free:
292 unregister_ftrace_function(dyn_ops);
293 kfree(dyn_ops);
294
295 out:
296 /* Purposely unregister in the same order */
297 unregister_ftrace_function(&test_probe1);
298 unregister_ftrace_function(&test_probe2);
299 unregister_ftrace_function(&test_probe3);
300 if (cnt > 1)
301 unregister_ftrace_function(tr->ops);
302 ftrace_reset_array_ops(tr);
303
304 /* Make sure everything is off */
305 reset_counts();
306 DYN_FTRACE_TEST_NAME();
307 DYN_FTRACE_TEST_NAME();
308
309 if (trace_selftest_test_probe1_cnt ||
310 trace_selftest_test_probe2_cnt ||
311 trace_selftest_test_probe3_cnt ||
312 trace_selftest_test_global_cnt ||
313 trace_selftest_test_dyn_cnt)
314 ret = -1;
315
316 ftrace_enabled = save_ftrace_enabled;
317
318 return ret;
319}
320
321/* Test dynamic code modification and ftrace filters */
322static int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
323 struct trace_array *tr,
324 int (*func)(void))
325{
326 int save_ftrace_enabled = ftrace_enabled;
327 unsigned long count;
328 char *func_name;
329 int ret;
330
331 /* The ftrace test PASSED */
332 printk(KERN_CONT "PASSED\n");
333 pr_info("Testing dynamic ftrace: ");
334
335 /* enable tracing, and record the filter function */
336 ftrace_enabled = 1;
337
338 /* passed in by parameter to fool gcc from optimizing */
339 func();
340
341 /*
342 * Some archs *cough*PowerPC*cough* add characters to the
343 * start of the function names. We simply put a '*' to
344 * accommodate them.
345 */
346 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
347
348 /* filter only on our function */
349 ftrace_set_global_filter(func_name, strlen(func_name), 1);
350
351 /* enable tracing */
352 ret = tracer_init(trace, tr);
353 if (ret) {
354 warn_failed_init_tracer(trace, ret);
355 goto out;
356 }
357
358 /* Sleep for a 1/10 of a second */
359 msleep(100);
360
361 /* we should have nothing in the buffer */
362 ret = trace_test_buffer(&tr->array_buffer, &count);
363 if (ret)
364 goto out;
365
366 if (count) {
367 ret = -1;
368 printk(KERN_CONT ".. filter did not filter .. ");
369 goto out;
370 }
371
372 /* call our function again */
373 func();
374
375 /* sleep again */
376 msleep(100);
377
378 /* stop the tracing. */
379 tracing_stop();
380 ftrace_enabled = 0;
381
382 /* check the trace buffer */
383 ret = trace_test_buffer(&tr->array_buffer, &count);
384
385 ftrace_enabled = 1;
386 tracing_start();
387
388 /* we should only have one item */
389 if (!ret && count != 1) {
390 trace->reset(tr);
391 printk(KERN_CONT ".. filter failed count=%ld ..", count);
392 ret = -1;
393 goto out;
394 }
395
396 /* Test the ops with global tracing running */
397 ret = trace_selftest_ops(tr, 1);
398 trace->reset(tr);
399
400 out:
401 ftrace_enabled = save_ftrace_enabled;
402
403 /* Enable tracing on all functions again */
404 ftrace_set_global_filter(NULL, 0, 1);
405
406 /* Test the ops with global tracing off */
407 if (!ret)
408 ret = trace_selftest_ops(tr, 2);
409
410 return ret;
411}
412
413static int trace_selftest_recursion_cnt;
414static void trace_selftest_test_recursion_func(unsigned long ip,
415 unsigned long pip,
416 struct ftrace_ops *op,
417 struct ftrace_regs *fregs)
418{
419 /*
420 * This function is registered without the recursion safe flag.
421 * The ftrace infrastructure should provide the recursion
422 * protection. If not, this will crash the kernel!
423 */
424 if (trace_selftest_recursion_cnt++ > 10)
425 return;
426 DYN_FTRACE_TEST_NAME();
427}
428
429static void trace_selftest_test_recursion_safe_func(unsigned long ip,
430 unsigned long pip,
431 struct ftrace_ops *op,
432 struct ftrace_regs *fregs)
433{
434 /*
435 * We said we would provide our own recursion. By calling
436 * this function again, we should recurse back into this function
437 * and count again. But this only happens if the arch supports
438 * all of ftrace features and nothing else is using the function
439 * tracing utility.
440 */
441 if (trace_selftest_recursion_cnt++)
442 return;
443 DYN_FTRACE_TEST_NAME();
444}
445
446static struct ftrace_ops test_rec_probe = {
447 .func = trace_selftest_test_recursion_func,
448 .flags = FTRACE_OPS_FL_RECURSION,
449};
450
451static struct ftrace_ops test_recsafe_probe = {
452 .func = trace_selftest_test_recursion_safe_func,
453};
454
455static int
456trace_selftest_function_recursion(void)
457{
458 int save_ftrace_enabled = ftrace_enabled;
459 char *func_name;
460 int len;
461 int ret;
462
463 /* The previous test PASSED */
464 pr_cont("PASSED\n");
465 pr_info("Testing ftrace recursion: ");
466
467
468 /* enable tracing, and record the filter function */
469 ftrace_enabled = 1;
470
471 /* Handle PPC64 '.' name */
472 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
473 len = strlen(func_name);
474
475 ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
476 if (ret) {
477 pr_cont("*Could not set filter* ");
478 goto out;
479 }
480
481 ret = register_ftrace_function(&test_rec_probe);
482 if (ret) {
483 pr_cont("*could not register callback* ");
484 goto out;
485 }
486
487 DYN_FTRACE_TEST_NAME();
488
489 unregister_ftrace_function(&test_rec_probe);
490
491 ret = -1;
492 /*
493 * Recursion allows for transitions between context,
494 * and may call the callback twice.
495 */
496 if (trace_selftest_recursion_cnt != 1 &&
497 trace_selftest_recursion_cnt != 2) {
498 pr_cont("*callback not called once (or twice) (%d)* ",
499 trace_selftest_recursion_cnt);
500 goto out;
501 }
502
503 trace_selftest_recursion_cnt = 1;
504
505 pr_cont("PASSED\n");
506 pr_info("Testing ftrace recursion safe: ");
507
508 ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
509 if (ret) {
510 pr_cont("*Could not set filter* ");
511 goto out;
512 }
513
514 ret = register_ftrace_function(&test_recsafe_probe);
515 if (ret) {
516 pr_cont("*could not register callback* ");
517 goto out;
518 }
519
520 DYN_FTRACE_TEST_NAME();
521
522 unregister_ftrace_function(&test_recsafe_probe);
523
524 ret = -1;
525 if (trace_selftest_recursion_cnt != 2) {
526 pr_cont("*callback not called expected 2 times (%d)* ",
527 trace_selftest_recursion_cnt);
528 goto out;
529 }
530
531 ret = 0;
532out:
533 ftrace_enabled = save_ftrace_enabled;
534
535 return ret;
536}
537#else
538# define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
539# define trace_selftest_function_recursion() ({ 0; })
540#endif /* CONFIG_DYNAMIC_FTRACE */
541
542static enum {
543 TRACE_SELFTEST_REGS_START,
544 TRACE_SELFTEST_REGS_FOUND,
545 TRACE_SELFTEST_REGS_NOT_FOUND,
546} trace_selftest_regs_stat;
547
548static void trace_selftest_test_regs_func(unsigned long ip,
549 unsigned long pip,
550 struct ftrace_ops *op,
551 struct ftrace_regs *fregs)
552{
553 struct pt_regs *regs = ftrace_get_regs(fregs);
554
555 if (regs)
556 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
557 else
558 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
559}
560
561static struct ftrace_ops test_regs_probe = {
562 .func = trace_selftest_test_regs_func,
563 .flags = FTRACE_OPS_FL_SAVE_REGS,
564};
565
566static int
567trace_selftest_function_regs(void)
568{
569 int save_ftrace_enabled = ftrace_enabled;
570 char *func_name;
571 int len;
572 int ret;
573 int supported = 0;
574
575#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
576 supported = 1;
577#endif
578
579 /* The previous test PASSED */
580 pr_cont("PASSED\n");
581 pr_info("Testing ftrace regs%s: ",
582 !supported ? "(no arch support)" : "");
583
584 /* enable tracing, and record the filter function */
585 ftrace_enabled = 1;
586
587 /* Handle PPC64 '.' name */
588 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
589 len = strlen(func_name);
590
591 ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
592 /*
593 * If DYNAMIC_FTRACE is not set, then we just trace all functions.
594 * This test really doesn't care.
595 */
596 if (ret && ret != -ENODEV) {
597 pr_cont("*Could not set filter* ");
598 goto out;
599 }
600
601 ret = register_ftrace_function(&test_regs_probe);
602 /*
603 * Now if the arch does not support passing regs, then this should
604 * have failed.
605 */
606 if (!supported) {
607 if (!ret) {
608 pr_cont("*registered save-regs without arch support* ");
609 goto out;
610 }
611 test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
612 ret = register_ftrace_function(&test_regs_probe);
613 }
614 if (ret) {
615 pr_cont("*could not register callback* ");
616 goto out;
617 }
618
619
620 DYN_FTRACE_TEST_NAME();
621
622 unregister_ftrace_function(&test_regs_probe);
623
624 ret = -1;
625
626 switch (trace_selftest_regs_stat) {
627 case TRACE_SELFTEST_REGS_START:
628 pr_cont("*callback never called* ");
629 goto out;
630
631 case TRACE_SELFTEST_REGS_FOUND:
632 if (supported)
633 break;
634 pr_cont("*callback received regs without arch support* ");
635 goto out;
636
637 case TRACE_SELFTEST_REGS_NOT_FOUND:
638 if (!supported)
639 break;
640 pr_cont("*callback received NULL regs* ");
641 goto out;
642 }
643
644 ret = 0;
645out:
646 ftrace_enabled = save_ftrace_enabled;
647
648 return ret;
649}
650
651/*
652 * Simple verification test of ftrace function tracer.
653 * Enable ftrace, sleep 1/10 second, and then read the trace
654 * buffer to see if all is in order.
655 */
656__init int
657trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
658{
659 int save_ftrace_enabled = ftrace_enabled;
660 unsigned long count;
661 int ret;
662
663#ifdef CONFIG_DYNAMIC_FTRACE
664 if (ftrace_filter_param) {
665 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
666 return 0;
667 }
668#endif
669
670 /* make sure msleep has been recorded */
671 msleep(1);
672
673 /* start the tracing */
674 ftrace_enabled = 1;
675
676 ret = tracer_init(trace, tr);
677 if (ret) {
678 warn_failed_init_tracer(trace, ret);
679 goto out;
680 }
681
682 /* Sleep for a 1/10 of a second */
683 msleep(100);
684 /* stop the tracing. */
685 tracing_stop();
686 ftrace_enabled = 0;
687
688 /* check the trace buffer */
689 ret = trace_test_buffer(&tr->array_buffer, &count);
690
691 ftrace_enabled = 1;
692 trace->reset(tr);
693 tracing_start();
694
695 if (!ret && !count) {
696 printk(KERN_CONT ".. no entries found ..");
697 ret = -1;
698 goto out;
699 }
700
701 ret = trace_selftest_startup_dynamic_tracing(trace, tr,
702 DYN_FTRACE_TEST_NAME);
703 if (ret)
704 goto out;
705
706 ret = trace_selftest_function_recursion();
707 if (ret)
708 goto out;
709
710 ret = trace_selftest_function_regs();
711 out:
712 ftrace_enabled = save_ftrace_enabled;
713
714 /* kill ftrace totally if we failed */
715 if (ret)
716 ftrace_kill();
717
718 return ret;
719}
720#endif /* CONFIG_FUNCTION_TRACER */
721
722
723#ifdef CONFIG_FUNCTION_GRAPH_TRACER
724
725/* Maximum number of functions to trace before diagnosing a hang */
726#define GRAPH_MAX_FUNC_TEST 100000000
727
728static unsigned int graph_hang_thresh;
729
730/* Wrap the real function entry probe to avoid possible hanging */
731static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
732{
733 /* This is harmlessly racy, we want to approximately detect a hang */
734 if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
735 ftrace_graph_stop();
736 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
737 if (ftrace_dump_on_oops) {
738 ftrace_dump(DUMP_ALL);
739 /* ftrace_dump() disables tracing */
740 tracing_on();
741 }
742 return 0;
743 }
744
745 return trace_graph_entry(trace);
746}
747
748static struct fgraph_ops fgraph_ops __initdata = {
749 .entryfunc = &trace_graph_entry_watchdog,
750 .retfunc = &trace_graph_return,
751};
752
753/*
754 * Pretty much the same than for the function tracer from which the selftest
755 * has been borrowed.
756 */
757__init int
758trace_selftest_startup_function_graph(struct tracer *trace,
759 struct trace_array *tr)
760{
761 int ret;
762 unsigned long count;
763
764#ifdef CONFIG_DYNAMIC_FTRACE
765 if (ftrace_filter_param) {
766 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
767 return 0;
768 }
769#endif
770
771 /*
772 * Simulate the init() callback but we attach a watchdog callback
773 * to detect and recover from possible hangs
774 */
775 tracing_reset_online_cpus(&tr->array_buffer);
776 set_graph_array(tr);
777 ret = register_ftrace_graph(&fgraph_ops);
778 if (ret) {
779 warn_failed_init_tracer(trace, ret);
780 goto out;
781 }
782 tracing_start_cmdline_record();
783
784 /* Sleep for a 1/10 of a second */
785 msleep(100);
786
787 /* Have we just recovered from a hang? */
788 if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
789 disable_tracing_selftest("recovering from a hang");
790 ret = -1;
791 goto out;
792 }
793
794 tracing_stop();
795
796 /* check the trace buffer */
797 ret = trace_test_buffer(&tr->array_buffer, &count);
798
799 /* Need to also simulate the tr->reset to remove this fgraph_ops */
800 tracing_stop_cmdline_record();
801 unregister_ftrace_graph(&fgraph_ops);
802
803 tracing_start();
804
805 if (!ret && !count) {
806 printk(KERN_CONT ".. no entries found ..");
807 ret = -1;
808 goto out;
809 }
810
811 /* Don't test dynamic tracing, the function tracer already did */
812
813out:
814 /* Stop it if we failed */
815 if (ret)
816 ftrace_graph_stop();
817
818 return ret;
819}
820#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
821
822
823#ifdef CONFIG_IRQSOFF_TRACER
824int
825trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
826{
827 unsigned long save_max = tr->max_latency;
828 unsigned long count;
829 int ret;
830
831 /* start the tracing */
832 ret = tracer_init(trace, tr);
833 if (ret) {
834 warn_failed_init_tracer(trace, ret);
835 return ret;
836 }
837
838 /* reset the max latency */
839 tr->max_latency = 0;
840 /* disable interrupts for a bit */
841 local_irq_disable();
842 udelay(100);
843 local_irq_enable();
844
845 /*
846 * Stop the tracer to avoid a warning subsequent
847 * to buffer flipping failure because tracing_stop()
848 * disables the tr and max buffers, making flipping impossible
849 * in case of parallels max irqs off latencies.
850 */
851 trace->stop(tr);
852 /* stop the tracing. */
853 tracing_stop();
854 /* check both trace buffers */
855 ret = trace_test_buffer(&tr->array_buffer, NULL);
856 if (!ret)
857 ret = trace_test_buffer(&tr->max_buffer, &count);
858 trace->reset(tr);
859 tracing_start();
860
861 if (!ret && !count) {
862 printk(KERN_CONT ".. no entries found ..");
863 ret = -1;
864 }
865
866 tr->max_latency = save_max;
867
868 return ret;
869}
870#endif /* CONFIG_IRQSOFF_TRACER */
871
872#ifdef CONFIG_PREEMPT_TRACER
873int
874trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
875{
876 unsigned long save_max = tr->max_latency;
877 unsigned long count;
878 int ret;
879
880 /*
881 * Now that the big kernel lock is no longer preemptible,
882 * and this is called with the BKL held, it will always
883 * fail. If preemption is already disabled, simply
884 * pass the test. When the BKL is removed, or becomes
885 * preemptible again, we will once again test this,
886 * so keep it in.
887 */
888 if (preempt_count()) {
889 printk(KERN_CONT "can not test ... force ");
890 return 0;
891 }
892
893 /* start the tracing */
894 ret = tracer_init(trace, tr);
895 if (ret) {
896 warn_failed_init_tracer(trace, ret);
897 return ret;
898 }
899
900 /* reset the max latency */
901 tr->max_latency = 0;
902 /* disable preemption for a bit */
903 preempt_disable();
904 udelay(100);
905 preempt_enable();
906
907 /*
908 * Stop the tracer to avoid a warning subsequent
909 * to buffer flipping failure because tracing_stop()
910 * disables the tr and max buffers, making flipping impossible
911 * in case of parallels max preempt off latencies.
912 */
913 trace->stop(tr);
914 /* stop the tracing. */
915 tracing_stop();
916 /* check both trace buffers */
917 ret = trace_test_buffer(&tr->array_buffer, NULL);
918 if (!ret)
919 ret = trace_test_buffer(&tr->max_buffer, &count);
920 trace->reset(tr);
921 tracing_start();
922
923 if (!ret && !count) {
924 printk(KERN_CONT ".. no entries found ..");
925 ret = -1;
926 }
927
928 tr->max_latency = save_max;
929
930 return ret;
931}
932#endif /* CONFIG_PREEMPT_TRACER */
933
934#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
935int
936trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
937{
938 unsigned long save_max = tr->max_latency;
939 unsigned long count;
940 int ret;
941
942 /*
943 * Now that the big kernel lock is no longer preemptible,
944 * and this is called with the BKL held, it will always
945 * fail. If preemption is already disabled, simply
946 * pass the test. When the BKL is removed, or becomes
947 * preemptible again, we will once again test this,
948 * so keep it in.
949 */
950 if (preempt_count()) {
951 printk(KERN_CONT "can not test ... force ");
952 return 0;
953 }
954
955 /* start the tracing */
956 ret = tracer_init(trace, tr);
957 if (ret) {
958 warn_failed_init_tracer(trace, ret);
959 goto out_no_start;
960 }
961
962 /* reset the max latency */
963 tr->max_latency = 0;
964
965 /* disable preemption and interrupts for a bit */
966 preempt_disable();
967 local_irq_disable();
968 udelay(100);
969 preempt_enable();
970 /* reverse the order of preempt vs irqs */
971 local_irq_enable();
972
973 /*
974 * Stop the tracer to avoid a warning subsequent
975 * to buffer flipping failure because tracing_stop()
976 * disables the tr and max buffers, making flipping impossible
977 * in case of parallels max irqs/preempt off latencies.
978 */
979 trace->stop(tr);
980 /* stop the tracing. */
981 tracing_stop();
982 /* check both trace buffers */
983 ret = trace_test_buffer(&tr->array_buffer, NULL);
984 if (ret)
985 goto out;
986
987 ret = trace_test_buffer(&tr->max_buffer, &count);
988 if (ret)
989 goto out;
990
991 if (!ret && !count) {
992 printk(KERN_CONT ".. no entries found ..");
993 ret = -1;
994 goto out;
995 }
996
997 /* do the test by disabling interrupts first this time */
998 tr->max_latency = 0;
999 tracing_start();
1000 trace->start(tr);
1001
1002 preempt_disable();
1003 local_irq_disable();
1004 udelay(100);
1005 preempt_enable();
1006 /* reverse the order of preempt vs irqs */
1007 local_irq_enable();
1008
1009 trace->stop(tr);
1010 /* stop the tracing. */
1011 tracing_stop();
1012 /* check both trace buffers */
1013 ret = trace_test_buffer(&tr->array_buffer, NULL);
1014 if (ret)
1015 goto out;
1016
1017 ret = trace_test_buffer(&tr->max_buffer, &count);
1018
1019 if (!ret && !count) {
1020 printk(KERN_CONT ".. no entries found ..");
1021 ret = -1;
1022 goto out;
1023 }
1024
1025out:
1026 tracing_start();
1027out_no_start:
1028 trace->reset(tr);
1029 tr->max_latency = save_max;
1030
1031 return ret;
1032}
1033#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
1034
1035#ifdef CONFIG_NOP_TRACER
1036int
1037trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1038{
1039 /* What could possibly go wrong? */
1040 return 0;
1041}
1042#endif
1043
1044#ifdef CONFIG_SCHED_TRACER
1045
1046struct wakeup_test_data {
1047 struct completion is_ready;
1048 int go;
1049};
1050
1051static int trace_wakeup_test_thread(void *data)
1052{
1053 /* Make this a -deadline thread */
1054 static const struct sched_attr attr = {
1055 .sched_policy = SCHED_DEADLINE,
1056 .sched_runtime = 100000ULL,
1057 .sched_deadline = 10000000ULL,
1058 .sched_period = 10000000ULL
1059 };
1060 struct wakeup_test_data *x = data;
1061
1062 sched_setattr(current, &attr);
1063
1064 /* Make it know we have a new prio */
1065 complete(&x->is_ready);
1066
1067 /* now go to sleep and let the test wake us up */
1068 set_current_state(TASK_INTERRUPTIBLE);
1069 while (!x->go) {
1070 schedule();
1071 set_current_state(TASK_INTERRUPTIBLE);
1072 }
1073
1074 complete(&x->is_ready);
1075
1076 set_current_state(TASK_INTERRUPTIBLE);
1077
1078 /* we are awake, now wait to disappear */
1079 while (!kthread_should_stop()) {
1080 schedule();
1081 set_current_state(TASK_INTERRUPTIBLE);
1082 }
1083
1084 __set_current_state(TASK_RUNNING);
1085
1086 return 0;
1087}
1088int
1089trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1090{
1091 unsigned long save_max = tr->max_latency;
1092 struct task_struct *p;
1093 struct wakeup_test_data data;
1094 unsigned long count;
1095 int ret;
1096
1097 memset(&data, 0, sizeof(data));
1098
1099 init_completion(&data.is_ready);
1100
1101 /* create a -deadline thread */
1102 p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test");
1103 if (IS_ERR(p)) {
1104 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1105 return -1;
1106 }
1107
1108 /* make sure the thread is running at -deadline policy */
1109 wait_for_completion(&data.is_ready);
1110
1111 /* start the tracing */
1112 ret = tracer_init(trace, tr);
1113 if (ret) {
1114 warn_failed_init_tracer(trace, ret);
1115 return ret;
1116 }
1117
1118 /* reset the max latency */
1119 tr->max_latency = 0;
1120
1121 while (p->on_rq) {
1122 /*
1123 * Sleep to make sure the -deadline thread is asleep too.
1124 * On virtual machines we can't rely on timings,
1125 * but we want to make sure this test still works.
1126 */
1127 msleep(100);
1128 }
1129
1130 init_completion(&data.is_ready);
1131
1132 data.go = 1;
1133 /* memory barrier is in the wake_up_process() */
1134
1135 wake_up_process(p);
1136
1137 /* Wait for the task to wake up */
1138 wait_for_completion(&data.is_ready);
1139
1140 /* stop the tracing. */
1141 tracing_stop();
1142 /* check both trace buffers */
1143 ret = trace_test_buffer(&tr->array_buffer, NULL);
1144 if (!ret)
1145 ret = trace_test_buffer(&tr->max_buffer, &count);
1146
1147
1148 trace->reset(tr);
1149 tracing_start();
1150
1151 tr->max_latency = save_max;
1152
1153 /* kill the thread */
1154 kthread_stop(p);
1155
1156 if (!ret && !count) {
1157 printk(KERN_CONT ".. no entries found ..");
1158 ret = -1;
1159 }
1160
1161 return ret;
1162}
1163#endif /* CONFIG_SCHED_TRACER */
1164
1165#ifdef CONFIG_BRANCH_TRACER
1166int
1167trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1168{
1169 unsigned long count;
1170 int ret;
1171
1172 /* start the tracing */
1173 ret = tracer_init(trace, tr);
1174 if (ret) {
1175 warn_failed_init_tracer(trace, ret);
1176 return ret;
1177 }
1178
1179 /* Sleep for a 1/10 of a second */
1180 msleep(100);
1181 /* stop the tracing. */
1182 tracing_stop();
1183 /* check the trace buffer */
1184 ret = trace_test_buffer(&tr->array_buffer, &count);
1185 trace->reset(tr);
1186 tracing_start();
1187
1188 if (!ret && !count) {
1189 printk(KERN_CONT ".. no entries found ..");
1190 ret = -1;
1191 }
1192
1193 return ret;
1194}
1195#endif /* CONFIG_BRANCH_TRACER */
1196