1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Based on code from the latency_tracer, that is:
9 *
10 * Copyright (C) 2004-2006 Ingo Molnar
11 * Copyright (C) 2004 Nadia Yvette Chambers
12 */
13 #include <linux/ring_buffer.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/ftrace.h>
17 #include <linux/slab.h>
18 #include <linux/fs.h>
19
20 #include "trace.h"
21
22 static void tracing_start_function_trace(struct trace_array *tr);
23 static void tracing_stop_function_trace(struct trace_array *tr);
24 static void
25 function_trace_call(unsigned long ip, unsigned long parent_ip,
26 struct ftrace_ops *op, struct ftrace_regs *fregs);
27 static void
28 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
29 struct ftrace_ops *op, struct ftrace_regs *fregs);
30 static void
31 function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
32 struct ftrace_ops *op, struct ftrace_regs *fregs);
33 static void
34 function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
35 struct ftrace_ops *op,
36 struct ftrace_regs *fregs);
37 static struct tracer_flags func_flags;
38
39 /* Our option */
40 enum {
41
42 TRACE_FUNC_NO_OPTS = 0x0, /* No flags set. */
43 TRACE_FUNC_OPT_STACK = 0x1,
44 TRACE_FUNC_OPT_NO_REPEATS = 0x2,
45
46 /* Update this to next highest bit. */
47 TRACE_FUNC_OPT_HIGHEST_BIT = 0x4
48 };
49
50 #define TRACE_FUNC_OPT_MASK (TRACE_FUNC_OPT_HIGHEST_BIT - 1)
51
52 int ftrace_allocate_ftrace_ops(struct trace_array *tr)
53 {
54 struct ftrace_ops *ops;
55
56 /* The top level array uses the "global_ops" */
57 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
58 return 0;
59
60 ops = kzalloc(sizeof(*ops), GFP_KERNEL);
61 if (!ops)
62 return -ENOMEM;
63
64 /* Currently only the non stack version is supported */
65 ops->func = function_trace_call;
66 ops->flags = FTRACE_OPS_FL_PID;
67
68 tr->ops = ops;
69 ops->private = tr;
70
71 return 0;
72 }
73
74 void ftrace_free_ftrace_ops(struct trace_array *tr)
75 {
76 kfree(tr->ops);
77 tr->ops = NULL;
78 }
79
80 int ftrace_create_function_files(struct trace_array *tr,
81 struct dentry *parent)
82 {
83 int ret;
84 /*
85 * The top level array uses the "global_ops", and the files are
86 * created on boot up.
87 */
88 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
89 return 0;
90
91 if (!tr->ops)
92 return -EINVAL;
93
94 ret = allocate_fgraph_ops(tr, tr->ops);
95 if (ret) {
96 kfree(tr->ops);
97 return ret;
98 }
99
100 ftrace_create_filter_files(tr->ops, parent);
101
102 return 0;
103 }
104
105 void ftrace_destroy_function_files(struct trace_array *tr)
106 {
107 ftrace_destroy_filter_files(tr->ops);
108 ftrace_free_ftrace_ops(tr);
109 free_fgraph_ops(tr);
110 }
111
112 static ftrace_func_t select_trace_function(u32 flags_val)
113 {
114 switch (flags_val & TRACE_FUNC_OPT_MASK) {
115 case TRACE_FUNC_NO_OPTS:
116 return function_trace_call;
117 case TRACE_FUNC_OPT_STACK:
118 return function_stack_trace_call;
119 case TRACE_FUNC_OPT_NO_REPEATS:
120 return function_no_repeats_trace_call;
121 case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS:
122 return function_stack_no_repeats_trace_call;
123 default:
124 return NULL;
125 }
126 }
127
128 static bool handle_func_repeats(struct trace_array *tr, u32 flags_val)
129 {
130 if (!tr->last_func_repeats &&
131 (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) {
132 tr->last_func_repeats = alloc_percpu(struct trace_func_repeats);
133 if (!tr->last_func_repeats)
134 return false;
135 }
136
137 return true;
138 }
139
140 static int function_trace_init(struct trace_array *tr)
141 {
142 ftrace_func_t func;
143 /*
144 * Instance trace_arrays get their ops allocated
145 * at instance creation. Unless it failed
146 * the allocation.
147 */
148 if (!tr->ops)
149 return -ENOMEM;
150
151 func = select_trace_function(func_flags.val);
152 if (!func)
153 return -EINVAL;
154
155 if (!handle_func_repeats(tr, func_flags.val))
156 return -ENOMEM;
157
158 ftrace_init_array_ops(tr, func);
159
160 tr->array_buffer.cpu = raw_smp_processor_id();
161
162 tracing_start_cmdline_record();
163 tracing_start_function_trace(tr);
164 return 0;
165 }
166
167 static void function_trace_reset(struct trace_array *tr)
168 {
169 tracing_stop_function_trace(tr);
170 tracing_stop_cmdline_record();
171 ftrace_reset_array_ops(tr);
172 }
173
174 static void function_trace_start(struct trace_array *tr)
175 {
176 tracing_reset_online_cpus(&tr->array_buffer);
177 }
178
179 static void
180 function_trace_call(unsigned long ip, unsigned long parent_ip,
181 struct ftrace_ops *op, struct ftrace_regs *fregs)
182 {
183 struct trace_array *tr = op->private;
184 struct trace_array_cpu *data;
185 unsigned int trace_ctx;
186 int bit;
187 int cpu;
188
189 if (unlikely(!tr->function_enabled))
190 return;
191
192 bit = ftrace_test_recursion_trylock(ip, parent_ip);
193 if (bit < 0)
194 return;
195
196 trace_ctx = tracing_gen_ctx();
197
198 cpu = smp_processor_id();
199 data = per_cpu_ptr(tr->array_buffer.data, cpu);
200 if (!atomic_read(&data->disabled))
201 trace_function(tr, ip, parent_ip, trace_ctx);
202
203 ftrace_test_recursion_unlock(bit);
204 }
205
206 #ifdef CONFIG_UNWINDER_ORC
207 /*
208 * Skip 2:
209 *
210 * function_stack_trace_call()
211 * ftrace_call()
212 */
213 #define STACK_SKIP 2
214 #else
215 /*
216 * Skip 3:
217 * __trace_stack()
218 * function_stack_trace_call()
219 * ftrace_call()
220 */
221 #define STACK_SKIP 3
222 #endif
223
224 static void
225 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
226 struct ftrace_ops *op, struct ftrace_regs *fregs)
227 {
228 struct trace_array *tr = op->private;
229 struct trace_array_cpu *data;
230 unsigned long flags;
231 long disabled;
232 int cpu;
233 unsigned int trace_ctx;
234 int skip = STACK_SKIP;
235
236 if (unlikely(!tr->function_enabled))
237 return;
238
239 /*
240 * Need to use raw, since this must be called before the
241 * recursive protection is performed.
242 */
243 local_irq_save(flags);
244 cpu = raw_smp_processor_id();
245 data = per_cpu_ptr(tr->array_buffer.data, cpu);
246 disabled = atomic_inc_return(&data->disabled);
247
248 if (likely(disabled == 1)) {
249 trace_ctx = tracing_gen_ctx_flags(flags);
250 trace_function(tr, ip, parent_ip, trace_ctx);
251 #ifdef CONFIG_UNWINDER_FRAME_POINTER
252 if (ftrace_pids_enabled(op))
253 skip++;
254 #endif
255 __trace_stack(tr, trace_ctx, skip);
256 }
257
258 atomic_dec(&data->disabled);
259 local_irq_restore(flags);
260 }
261
262 static inline bool is_repeat_check(struct trace_array *tr,
263 struct trace_func_repeats *last_info,
264 unsigned long ip, unsigned long parent_ip)
265 {
266 if (last_info->ip == ip &&
267 last_info->parent_ip == parent_ip &&
268 last_info->count < U16_MAX) {
269 last_info->ts_last_call =
270 ring_buffer_time_stamp(tr->array_buffer.buffer);
271 last_info->count++;
272 return true;
273 }
274
275 return false;
276 }
277
278 static inline void process_repeats(struct trace_array *tr,
279 unsigned long ip, unsigned long parent_ip,
280 struct trace_func_repeats *last_info,
281 unsigned int trace_ctx)
282 {
283 if (last_info->count) {
284 trace_last_func_repeats(tr, last_info, trace_ctx);
285 last_info->count = 0;
286 }
287
288 last_info->ip = ip;
289 last_info->parent_ip = parent_ip;
290 }
291
292 static void
293 function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
294 struct ftrace_ops *op,
295 struct ftrace_regs *fregs)
296 {
297 struct trace_func_repeats *last_info;
298 struct trace_array *tr = op->private;
299 struct trace_array_cpu *data;
300 unsigned int trace_ctx;
301 unsigned long flags;
302 int bit;
303 int cpu;
304
305 if (unlikely(!tr->function_enabled))
306 return;
307
308 bit = ftrace_test_recursion_trylock(ip, parent_ip);
309 if (bit < 0)
310 return;
311
312 cpu = smp_processor_id();
313 data = per_cpu_ptr(tr->array_buffer.data, cpu);
314 if (atomic_read(&data->disabled))
315 goto out;
316
317 /*
318 * An interrupt may happen at any place here. But as far as I can see,
319 * the only damage that this can cause is to mess up the repetition
320 * counter without valuable data being lost.
321 * TODO: think about a solution that is better than just hoping to be
322 * lucky.
323 */
324 last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
325 if (is_repeat_check(tr, last_info, ip, parent_ip))
326 goto out;
327
328 local_save_flags(flags);
329 trace_ctx = tracing_gen_ctx_flags(flags);
330 process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
331
332 trace_function(tr, ip, parent_ip, trace_ctx);
333
334 out:
335 ftrace_test_recursion_unlock(bit);
336 }
337
338 static void
339 function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
340 struct ftrace_ops *op,
341 struct ftrace_regs *fregs)
342 {
343 struct trace_func_repeats *last_info;
344 struct trace_array *tr = op->private;
345 struct trace_array_cpu *data;
346 unsigned long flags;
347 long disabled;
348 int cpu;
349 unsigned int trace_ctx;
350
351 if (unlikely(!tr->function_enabled))
352 return;
353
354 /*
355 * Need to use raw, since this must be called before the
356 * recursive protection is performed.
357 */
358 local_irq_save(flags);
359 cpu = raw_smp_processor_id();
360 data = per_cpu_ptr(tr->array_buffer.data, cpu);
361 disabled = atomic_inc_return(&data->disabled);
362
363 if (likely(disabled == 1)) {
364 last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
365 if (is_repeat_check(tr, last_info, ip, parent_ip))
366 goto out;
367
368 trace_ctx = tracing_gen_ctx_flags(flags);
369 process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
370
371 trace_function(tr, ip, parent_ip, trace_ctx);
372 __trace_stack(tr, trace_ctx, STACK_SKIP);
373 }
374
375 out:
376 atomic_dec(&data->disabled);
377 local_irq_restore(flags);
378 }
379
380 static struct tracer_opt func_opts[] = {
381 #ifdef CONFIG_STACKTRACE
382 { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
383 #endif
384 { TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
385 { } /* Always set a last empty entry */
386 };
387
388 static struct tracer_flags func_flags = {
389 .val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */
390 .opts = func_opts
391 };
392
393 static void tracing_start_function_trace(struct trace_array *tr)
394 {
395 tr->function_enabled = 0;
396 register_ftrace_function(tr->ops);
397 tr->function_enabled = 1;
398 }
399
400 static void tracing_stop_function_trace(struct trace_array *tr)
401 {
402 tr->function_enabled = 0;
403 unregister_ftrace_function(tr->ops);
404 }
405
406 static struct tracer function_trace;
407
408 static int
409 func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
410 {
411 ftrace_func_t func;
412 u32 new_flags;
413
414 /* Do nothing if already set. */
415 if (!!set == !!(func_flags.val & bit))
416 return 0;
417
418 /* We can change this flag only when not running. */
419 if (tr->current_trace != &function_trace)
420 return 0;
421
422 new_flags = (func_flags.val & ~bit) | (set ? bit : 0);
423 func = select_trace_function(new_flags);
424 if (!func)
425 return -EINVAL;
426
427 /* Check if there's anything to change. */
428 if (tr->ops->func == func)
429 return 0;
430
431 if (!handle_func_repeats(tr, new_flags))
432 return -ENOMEM;
433
434 unregister_ftrace_function(tr->ops);
435 tr->ops->func = func;
436 register_ftrace_function(tr->ops);
437
438 return 0;
439 }
440
441 static struct tracer function_trace __tracer_data =
442 {
443 .name = "function",
444 .init = function_trace_init,
445 .reset = function_trace_reset,
446 .start = function_trace_start,
447 .flags = &func_flags,
448 .set_flag = func_set_flag,
449 .allow_instances = true,
450 #ifdef CONFIG_FTRACE_SELFTEST
451 .selftest = trace_selftest_startup_function,
452 #endif
453 };
454
455 #ifdef CONFIG_DYNAMIC_FTRACE
456 static void update_traceon_count(struct ftrace_probe_ops *ops,
457 unsigned long ip,
458 struct trace_array *tr, bool on,
459 void *data)
460 {
461 struct ftrace_func_mapper *mapper = data;
462 long *count;
463 long old_count;
464
465 /*
466 * Tracing gets disabled (or enabled) once per count.
467 * This function can be called at the same time on multiple CPUs.
468 * It is fine if both disable (or enable) tracing, as disabling
469 * (or enabling) the second time doesn't do anything as the
470 * state of the tracer is already disabled (or enabled).
471 * What needs to be synchronized in this case is that the count
472 * only gets decremented once, even if the tracer is disabled
473 * (or enabled) twice, as the second one is really a nop.
474 *
475 * The memory barriers guarantee that we only decrement the
476 * counter once. First the count is read to a local variable
477 * and a read barrier is used to make sure that it is loaded
478 * before checking if the tracer is in the state we want.
479 * If the tracer is not in the state we want, then the count
480 * is guaranteed to be the old count.
481 *
482 * Next the tracer is set to the state we want (disabled or enabled)
483 * then a write memory barrier is used to make sure that
484 * the new state is visible before changing the counter by
485 * one minus the old counter. This guarantees that another CPU
486 * executing this code will see the new state before seeing
487 * the new counter value, and would not do anything if the new
488 * counter is seen.
489 *
490 * Note, there is no synchronization between this and a user
491 * setting the tracing_on file. But we currently don't care
492 * about that.
493 */
494 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
495 old_count = *count;
496
497 if (old_count <= 0)
498 return;
499
500 /* Make sure we see count before checking tracing state */
501 smp_rmb();
502
503 if (on == !!tracer_tracing_is_on(tr))
504 return;
505
506 if (on)
507 tracer_tracing_on(tr);
508 else
509 tracer_tracing_off(tr);
510
511 /* Make sure tracing state is visible before updating count */
512 smp_wmb();
513
514 *count = old_count - 1;
515 }
516
517 static void
518 ftrace_traceon_count(unsigned long ip, unsigned long parent_ip,
519 struct trace_array *tr, struct ftrace_probe_ops *ops,
520 void *data)
521 {
522 update_traceon_count(ops, ip, tr, 1, data);
523 }
524
525 static void
526 ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip,
527 struct trace_array *tr, struct ftrace_probe_ops *ops,
528 void *data)
529 {
530 update_traceon_count(ops, ip, tr, 0, data);
531 }
532
533 static void
534 ftrace_traceon(unsigned long ip, unsigned long parent_ip,
535 struct trace_array *tr, struct ftrace_probe_ops *ops,
536 void *data)
537 {
538 if (tracer_tracing_is_on(tr))
539 return;
540
541 tracer_tracing_on(tr);
542 }
543
544 static void
545 ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
546 struct trace_array *tr, struct ftrace_probe_ops *ops,
547 void *data)
548 {
549 if (!tracer_tracing_is_on(tr))
550 return;
551
552 tracer_tracing_off(tr);
553 }
554
555 #ifdef CONFIG_UNWINDER_ORC
556 /*
557 * Skip 3:
558 *
559 * function_trace_probe_call()
560 * ftrace_ops_assist_func()
561 * ftrace_call()
562 */
563 #define FTRACE_STACK_SKIP 3
564 #else
565 /*
566 * Skip 5:
567 *
568 * __trace_stack()
569 * ftrace_stacktrace()
570 * function_trace_probe_call()
571 * ftrace_ops_assist_func()
572 * ftrace_call()
573 */
574 #define FTRACE_STACK_SKIP 5
575 #endif
576
577 static __always_inline void trace_stack(struct trace_array *tr)
578 {
579 unsigned int trace_ctx;
580
581 trace_ctx = tracing_gen_ctx();
582
583 __trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP);
584 }
585
586 static void
587 ftrace_stacktrace(unsigned long ip, unsigned long parent_ip,
588 struct trace_array *tr, struct ftrace_probe_ops *ops,
589 void *data)
590 {
591 trace_stack(tr);
592 }
593
594 static void
595 ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip,
596 struct trace_array *tr, struct ftrace_probe_ops *ops,
597 void *data)
598 {
599 struct ftrace_func_mapper *mapper = data;
600 long *count;
601 long old_count;
602 long new_count;
603
604 if (!tracing_is_on())
605 return;
606
607 /* unlimited? */
608 if (!mapper) {
609 trace_stack(tr);
610 return;
611 }
612
613 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
614
615 /*
616 * Stack traces should only execute the number of times the
617 * user specified in the counter.
618 */
619 do {
620 old_count = *count;
621
622 if (!old_count)
623 return;
624
625 new_count = old_count - 1;
626 new_count = cmpxchg(count, old_count, new_count);
627 if (new_count == old_count)
628 trace_stack(tr);
629
630 if (!tracing_is_on())
631 return;
632
633 } while (new_count != old_count);
634 }
635
636 static int update_count(struct ftrace_probe_ops *ops, unsigned long ip,
637 void *data)
638 {
639 struct ftrace_func_mapper *mapper = data;
640 long *count = NULL;
641
642 if (mapper)
643 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
644
645 if (count) {
646 if (*count <= 0)
647 return 0;
648 (*count)--;
649 }
650
651 return 1;
652 }
653
654 static void
655 ftrace_dump_probe(unsigned long ip, unsigned long parent_ip,
656 struct trace_array *tr, struct ftrace_probe_ops *ops,
657 void *data)
658 {
659 if (update_count(ops, ip, data))
660 ftrace_dump(DUMP_ALL);
661 }
662
663 /* Only dump the current CPU buffer. */
664 static void
665 ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip,
666 struct trace_array *tr, struct ftrace_probe_ops *ops,
667 void *data)
668 {
669 if (update_count(ops, ip, data))
670 ftrace_dump(DUMP_ORIG);
671 }
672
673 static int
674 ftrace_probe_print(const char *name, struct seq_file *m,
675 unsigned long ip, struct ftrace_probe_ops *ops,
676 void *data)
677 {
678 struct ftrace_func_mapper *mapper = data;
679 long *count = NULL;
680
681 seq_printf(m, "%ps:%s", (void *)ip, name);
682
683 if (mapper)
684 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
685
686 if (count)
687 seq_printf(m, ":count=%ld\n", *count);
688 else
689 seq_puts(m, ":unlimited\n");
690
691 return 0;
692 }
693
694 static int
695 ftrace_traceon_print(struct seq_file *m, unsigned long ip,
696 struct ftrace_probe_ops *ops,
697 void *data)
698 {
699 return ftrace_probe_print("traceon", m, ip, ops, data);
700 }
701
702 static int
703 ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
704 struct ftrace_probe_ops *ops, void *data)
705 {
706 return ftrace_probe_print("traceoff", m, ip, ops, data);
707 }
708
709 static int
710 ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
711 struct ftrace_probe_ops *ops, void *data)
712 {
713 return ftrace_probe_print("stacktrace", m, ip, ops, data);
714 }
715
716 static int
717 ftrace_dump_print(struct seq_file *m, unsigned long ip,
718 struct ftrace_probe_ops *ops, void *data)
719 {
720 return ftrace_probe_print("dump", m, ip, ops, data);
721 }
722
723 static int
724 ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
725 struct ftrace_probe_ops *ops, void *data)
726 {
727 return ftrace_probe_print("cpudump", m, ip, ops, data);
728 }
729
730
731 static int
732 ftrace_count_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
733 unsigned long ip, void *init_data, void **data)
734 {
735 struct ftrace_func_mapper *mapper = *data;
736
737 if (!mapper) {
738 mapper = allocate_ftrace_func_mapper();
739 if (!mapper)
740 return -ENOMEM;
741 *data = mapper;
742 }
743
744 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
745 }
746
747 static void
748 ftrace_count_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
749 unsigned long ip, void *data)
750 {
751 struct ftrace_func_mapper *mapper = data;
752
753 if (!ip) {
754 free_ftrace_func_mapper(mapper, NULL);
755 return;
756 }
757
758 ftrace_func_mapper_remove_ip(mapper, ip);
759 }
760
761 static struct ftrace_probe_ops traceon_count_probe_ops = {
762 .func = ftrace_traceon_count,
763 .print = ftrace_traceon_print,
764 .init = ftrace_count_init,
765 .free = ftrace_count_free,
766 };
767
768 static struct ftrace_probe_ops traceoff_count_probe_ops = {
769 .func = ftrace_traceoff_count,
770 .print = ftrace_traceoff_print,
771 .init = ftrace_count_init,
772 .free = ftrace_count_free,
773 };
774
775 static struct ftrace_probe_ops stacktrace_count_probe_ops = {
776 .func = ftrace_stacktrace_count,
777 .print = ftrace_stacktrace_print,
778 .init = ftrace_count_init,
779 .free = ftrace_count_free,
780 };
781
782 static struct ftrace_probe_ops dump_probe_ops = {
783 .func = ftrace_dump_probe,
784 .print = ftrace_dump_print,
785 .init = ftrace_count_init,
786 .free = ftrace_count_free,
787 };
788
789 static struct ftrace_probe_ops cpudump_probe_ops = {
790 .func = ftrace_cpudump_probe,
791 .print = ftrace_cpudump_print,
792 };
793
794 static struct ftrace_probe_ops traceon_probe_ops = {
795 .func = ftrace_traceon,
796 .print = ftrace_traceon_print,
797 };
798
799 static struct ftrace_probe_ops traceoff_probe_ops = {
800 .func = ftrace_traceoff,
801 .print = ftrace_traceoff_print,
802 };
803
804 static struct ftrace_probe_ops stacktrace_probe_ops = {
805 .func = ftrace_stacktrace,
806 .print = ftrace_stacktrace_print,
807 };
808
809 static int
810 ftrace_trace_probe_callback(struct trace_array *tr,
811 struct ftrace_probe_ops *ops,
812 struct ftrace_hash *hash, char *glob,
813 char *cmd, char *param, int enable)
814 {
815 void *count = (void *)-1;
816 char *number;
817 int ret;
818
819 /* hash funcs only work with set_ftrace_filter */
820 if (!enable)
821 return -EINVAL;
822
823 if (glob[0] == '!')
824 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
825
826 if (!param)
827 goto out_reg;
828
829 number = strsep(¶m, ":");
830
831 if (!strlen(number))
832 goto out_reg;
833
834 /*
835 * We use the callback data field (which is a pointer)
836 * as our counter.
837 */
838 ret = kstrtoul(number, 0, (unsigned long *)&count);
839 if (ret)
840 return ret;
841
842 out_reg:
843 ret = register_ftrace_function_probe(glob, tr, ops, count);
844
845 return ret < 0 ? ret : 0;
846 }
847
848 static int
849 ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash,
850 char *glob, char *cmd, char *param, int enable)
851 {
852 struct ftrace_probe_ops *ops;
853
854 if (!tr)
855 return -ENODEV;
856
857 /* we register both traceon and traceoff to this callback */
858 if (strcmp(cmd, "traceon") == 0)
859 ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
860 else
861 ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;
862
863 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
864 param, enable);
865 }
866
867 static int
868 ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash,
869 char *glob, char *cmd, char *param, int enable)
870 {
871 struct ftrace_probe_ops *ops;
872
873 if (!tr)
874 return -ENODEV;
875
876 ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;
877
878 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
879 param, enable);
880 }
881
882 static int
883 ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash,
884 char *glob, char *cmd, char *param, int enable)
885 {
886 struct ftrace_probe_ops *ops;
887
888 if (!tr)
889 return -ENODEV;
890
891 ops = &dump_probe_ops;
892
893 /* Only dump once. */
894 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
895 "1", enable);
896 }
897
898 static int
899 ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash,
900 char *glob, char *cmd, char *param, int enable)
901 {
902 struct ftrace_probe_ops *ops;
903
904 if (!tr)
905 return -ENODEV;
906
907 ops = &cpudump_probe_ops;
908
909 /* Only dump once. */
910 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
911 "1", enable);
912 }
913
914 static struct ftrace_func_command ftrace_traceon_cmd = {
915 .name = "traceon",
916 .func = ftrace_trace_onoff_callback,
917 };
918
919 static struct ftrace_func_command ftrace_traceoff_cmd = {
920 .name = "traceoff",
921 .func = ftrace_trace_onoff_callback,
922 };
923
924 static struct ftrace_func_command ftrace_stacktrace_cmd = {
925 .name = "stacktrace",
926 .func = ftrace_stacktrace_callback,
927 };
928
929 static struct ftrace_func_command ftrace_dump_cmd = {
930 .name = "dump",
931 .func = ftrace_dump_callback,
932 };
933
934 static struct ftrace_func_command ftrace_cpudump_cmd = {
935 .name = "cpudump",
936 .func = ftrace_cpudump_callback,
937 };
938
939 static int __init init_func_cmd_traceon(void)
940 {
941 int ret;
942
943 ret = register_ftrace_command(&ftrace_traceoff_cmd);
944 if (ret)
945 return ret;
946
947 ret = register_ftrace_command(&ftrace_traceon_cmd);
948 if (ret)
949 goto out_free_traceoff;
950
951 ret = register_ftrace_command(&ftrace_stacktrace_cmd);
952 if (ret)
953 goto out_free_traceon;
954
955 ret = register_ftrace_command(&ftrace_dump_cmd);
956 if (ret)
957 goto out_free_stacktrace;
958
959 ret = register_ftrace_command(&ftrace_cpudump_cmd);
960 if (ret)
961 goto out_free_dump;
962
963 return 0;
964
965 out_free_dump:
966 unregister_ftrace_command(&ftrace_dump_cmd);
967 out_free_stacktrace:
968 unregister_ftrace_command(&ftrace_stacktrace_cmd);
969 out_free_traceon:
970 unregister_ftrace_command(&ftrace_traceon_cmd);
971 out_free_traceoff:
972 unregister_ftrace_command(&ftrace_traceoff_cmd);
973
974 return ret;
975 }
976 #else
977 static inline int init_func_cmd_traceon(void)
978 {
979 return 0;
980 }
981 #endif /* CONFIG_DYNAMIC_FTRACE */
982
983 __init int init_function_trace(void)
984 {
985 init_func_cmd_traceon();
986 return register_tracer(&function_trace);
987 }
988
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