Root/kernel/trace/trace_events.c

1/*
2 * event tracer
3 *
4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
5 *
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
8 *
9 */
10
11#include <linux/workqueue.h>
12#include <linux/spinlock.h>
13#include <linux/kthread.h>
14#include <linux/debugfs.h>
15#include <linux/uaccess.h>
16#include <linux/module.h>
17#include <linux/ctype.h>
18#include <linux/slab.h>
19#include <linux/delay.h>
20
21#include <asm/setup.h>
22
23#include "trace_output.h"
24
25#undef TRACE_SYSTEM
26#define TRACE_SYSTEM "TRACE_SYSTEM"
27
28DEFINE_MUTEX(event_mutex);
29
30DEFINE_MUTEX(event_storage_mutex);
31EXPORT_SYMBOL_GPL(event_storage_mutex);
32
33char event_storage[EVENT_STORAGE_SIZE];
34EXPORT_SYMBOL_GPL(event_storage);
35
36LIST_HEAD(ftrace_events);
37LIST_HEAD(ftrace_common_fields);
38
39struct list_head *
40trace_get_fields(struct ftrace_event_call *event_call)
41{
42    if (!event_call->class->get_fields)
43        return &event_call->class->fields;
44    return event_call->class->get_fields(event_call);
45}
46
47static int __trace_define_field(struct list_head *head, const char *type,
48                const char *name, int offset, int size,
49                int is_signed, int filter_type)
50{
51    struct ftrace_event_field *field;
52
53    field = kzalloc(sizeof(*field), GFP_KERNEL);
54    if (!field)
55        goto err;
56
57    field->name = kstrdup(name, GFP_KERNEL);
58    if (!field->name)
59        goto err;
60
61    field->type = kstrdup(type, GFP_KERNEL);
62    if (!field->type)
63        goto err;
64
65    if (filter_type == FILTER_OTHER)
66        field->filter_type = filter_assign_type(type);
67    else
68        field->filter_type = filter_type;
69
70    field->offset = offset;
71    field->size = size;
72    field->is_signed = is_signed;
73
74    list_add(&field->link, head);
75
76    return 0;
77
78err:
79    if (field)
80        kfree(field->name);
81    kfree(field);
82
83    return -ENOMEM;
84}
85
86int trace_define_field(struct ftrace_event_call *call, const char *type,
87               const char *name, int offset, int size, int is_signed,
88               int filter_type)
89{
90    struct list_head *head;
91
92    if (WARN_ON(!call->class))
93        return 0;
94
95    head = trace_get_fields(call);
96    return __trace_define_field(head, type, name, offset, size,
97                    is_signed, filter_type);
98}
99EXPORT_SYMBOL_GPL(trace_define_field);
100
101#define __common_field(type, item) \
102    ret = __trace_define_field(&ftrace_common_fields, #type, \
103                   "common_" #item, \
104                   offsetof(typeof(ent), item), \
105                   sizeof(ent.item), \
106                   is_signed_type(type), FILTER_OTHER); \
107    if (ret) \
108        return ret;
109
110static int trace_define_common_fields(void)
111{
112    int ret;
113    struct trace_entry ent;
114
115    __common_field(unsigned short, type);
116    __common_field(unsigned char, flags);
117    __common_field(unsigned char, preempt_count);
118    __common_field(int, pid);
119    __common_field(int, lock_depth);
120
121    return ret;
122}
123
124void trace_destroy_fields(struct ftrace_event_call *call)
125{
126    struct ftrace_event_field *field, *next;
127    struct list_head *head;
128
129    head = trace_get_fields(call);
130    list_for_each_entry_safe(field, next, head, link) {
131        list_del(&field->link);
132        kfree(field->type);
133        kfree(field->name);
134        kfree(field);
135    }
136}
137
138int trace_event_raw_init(struct ftrace_event_call *call)
139{
140    int id;
141
142    id = register_ftrace_event(&call->event);
143    if (!id)
144        return -ENODEV;
145
146    return 0;
147}
148EXPORT_SYMBOL_GPL(trace_event_raw_init);
149
150int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
151{
152    switch (type) {
153    case TRACE_REG_REGISTER:
154        return tracepoint_probe_register(call->name,
155                         call->class->probe,
156                         call);
157    case TRACE_REG_UNREGISTER:
158        tracepoint_probe_unregister(call->name,
159                        call->class->probe,
160                        call);
161        return 0;
162
163#ifdef CONFIG_PERF_EVENTS
164    case TRACE_REG_PERF_REGISTER:
165        return tracepoint_probe_register(call->name,
166                         call->class->perf_probe,
167                         call);
168    case TRACE_REG_PERF_UNREGISTER:
169        tracepoint_probe_unregister(call->name,
170                        call->class->perf_probe,
171                        call);
172        return 0;
173#endif
174    }
175    return 0;
176}
177EXPORT_SYMBOL_GPL(ftrace_event_reg);
178
179void trace_event_enable_cmd_record(bool enable)
180{
181    struct ftrace_event_call *call;
182
183    mutex_lock(&event_mutex);
184    list_for_each_entry(call, &ftrace_events, list) {
185        if (!(call->flags & TRACE_EVENT_FL_ENABLED))
186            continue;
187
188        if (enable) {
189            tracing_start_cmdline_record();
190            call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
191        } else {
192            tracing_stop_cmdline_record();
193            call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
194        }
195    }
196    mutex_unlock(&event_mutex);
197}
198
199static int ftrace_event_enable_disable(struct ftrace_event_call *call,
200                    int enable)
201{
202    int ret = 0;
203
204    switch (enable) {
205    case 0:
206        if (call->flags & TRACE_EVENT_FL_ENABLED) {
207            call->flags &= ~TRACE_EVENT_FL_ENABLED;
208            if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
209                tracing_stop_cmdline_record();
210                call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
211            }
212            call->class->reg(call, TRACE_REG_UNREGISTER);
213        }
214        break;
215    case 1:
216        if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
217            if (trace_flags & TRACE_ITER_RECORD_CMD) {
218                tracing_start_cmdline_record();
219                call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
220            }
221            ret = call->class->reg(call, TRACE_REG_REGISTER);
222            if (ret) {
223                tracing_stop_cmdline_record();
224                pr_info("event trace: Could not enable event "
225                    "%s\n", call->name);
226                break;
227            }
228            call->flags |= TRACE_EVENT_FL_ENABLED;
229        }
230        break;
231    }
232
233    return ret;
234}
235
236static void ftrace_clear_events(void)
237{
238    struct ftrace_event_call *call;
239
240    mutex_lock(&event_mutex);
241    list_for_each_entry(call, &ftrace_events, list) {
242        ftrace_event_enable_disable(call, 0);
243    }
244    mutex_unlock(&event_mutex);
245}
246
247/*
248 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
249 */
250static int __ftrace_set_clr_event(const char *match, const char *sub,
251                  const char *event, int set)
252{
253    struct ftrace_event_call *call;
254    int ret = -EINVAL;
255
256    mutex_lock(&event_mutex);
257    list_for_each_entry(call, &ftrace_events, list) {
258
259        if (!call->name || !call->class || !call->class->reg)
260            continue;
261
262        if (match &&
263            strcmp(match, call->name) != 0 &&
264            strcmp(match, call->class->system) != 0)
265            continue;
266
267        if (sub && strcmp(sub, call->class->system) != 0)
268            continue;
269
270        if (event && strcmp(event, call->name) != 0)
271            continue;
272
273        ftrace_event_enable_disable(call, set);
274
275        ret = 0;
276    }
277    mutex_unlock(&event_mutex);
278
279    return ret;
280}
281
282static int ftrace_set_clr_event(char *buf, int set)
283{
284    char *event = NULL, *sub = NULL, *match;
285
286    /*
287     * The buf format can be <subsystem>:<event-name>
288     * *:<event-name> means any event by that name.
289     * :<event-name> is the same.
290     *
291     * <subsystem>:* means all events in that subsystem
292     * <subsystem>: means the same.
293     *
294     * <name> (no ':') means all events in a subsystem with
295     * the name <name> or any event that matches <name>
296     */
297
298    match = strsep(&buf, ":");
299    if (buf) {
300        sub = match;
301        event = buf;
302        match = NULL;
303
304        if (!strlen(sub) || strcmp(sub, "*") == 0)
305            sub = NULL;
306        if (!strlen(event) || strcmp(event, "*") == 0)
307            event = NULL;
308    }
309
310    return __ftrace_set_clr_event(match, sub, event, set);
311}
312
313/**
314 * trace_set_clr_event - enable or disable an event
315 * @system: system name to match (NULL for any system)
316 * @event: event name to match (NULL for all events, within system)
317 * @set: 1 to enable, 0 to disable
318 *
319 * This is a way for other parts of the kernel to enable or disable
320 * event recording.
321 *
322 * Returns 0 on success, -EINVAL if the parameters do not match any
323 * registered events.
324 */
325int trace_set_clr_event(const char *system, const char *event, int set)
326{
327    return __ftrace_set_clr_event(NULL, system, event, set);
328}
329
330/* 128 should be much more than enough */
331#define EVENT_BUF_SIZE 127
332
333static ssize_t
334ftrace_event_write(struct file *file, const char __user *ubuf,
335           size_t cnt, loff_t *ppos)
336{
337    struct trace_parser parser;
338    ssize_t read, ret;
339
340    if (!cnt)
341        return 0;
342
343    ret = tracing_update_buffers();
344    if (ret < 0)
345        return ret;
346
347    if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
348        return -ENOMEM;
349
350    read = trace_get_user(&parser, ubuf, cnt, ppos);
351
352    if (read >= 0 && trace_parser_loaded((&parser))) {
353        int set = 1;
354
355        if (*parser.buffer == '!')
356            set = 0;
357
358        parser.buffer[parser.idx] = 0;
359
360        ret = ftrace_set_clr_event(parser.buffer + !set, set);
361        if (ret)
362            goto out_put;
363    }
364
365    ret = read;
366
367 out_put:
368    trace_parser_put(&parser);
369
370    return ret;
371}
372
373static void *
374t_next(struct seq_file *m, void *v, loff_t *pos)
375{
376    struct ftrace_event_call *call = v;
377
378    (*pos)++;
379
380    list_for_each_entry_continue(call, &ftrace_events, list) {
381        /*
382         * The ftrace subsystem is for showing formats only.
383         * They can not be enabled or disabled via the event files.
384         */
385        if (call->class && call->class->reg)
386            return call;
387    }
388
389    return NULL;
390}
391
392static void *t_start(struct seq_file *m, loff_t *pos)
393{
394    struct ftrace_event_call *call;
395    loff_t l;
396
397    mutex_lock(&event_mutex);
398
399    call = list_entry(&ftrace_events, struct ftrace_event_call, list);
400    for (l = 0; l <= *pos; ) {
401        call = t_next(m, call, &l);
402        if (!call)
403            break;
404    }
405    return call;
406}
407
408static void *
409s_next(struct seq_file *m, void *v, loff_t *pos)
410{
411    struct ftrace_event_call *call = v;
412
413    (*pos)++;
414
415    list_for_each_entry_continue(call, &ftrace_events, list) {
416        if (call->flags & TRACE_EVENT_FL_ENABLED)
417            return call;
418    }
419
420    return NULL;
421}
422
423static void *s_start(struct seq_file *m, loff_t *pos)
424{
425    struct ftrace_event_call *call;
426    loff_t l;
427
428    mutex_lock(&event_mutex);
429
430    call = list_entry(&ftrace_events, struct ftrace_event_call, list);
431    for (l = 0; l <= *pos; ) {
432        call = s_next(m, call, &l);
433        if (!call)
434            break;
435    }
436    return call;
437}
438
439static int t_show(struct seq_file *m, void *v)
440{
441    struct ftrace_event_call *call = v;
442
443    if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
444        seq_printf(m, "%s:", call->class->system);
445    seq_printf(m, "%s\n", call->name);
446
447    return 0;
448}
449
450static void t_stop(struct seq_file *m, void *p)
451{
452    mutex_unlock(&event_mutex);
453}
454
455static int
456ftrace_event_seq_open(struct inode *inode, struct file *file)
457{
458    const struct seq_operations *seq_ops;
459
460    if ((file->f_mode & FMODE_WRITE) &&
461        (file->f_flags & O_TRUNC))
462        ftrace_clear_events();
463
464    seq_ops = inode->i_private;
465    return seq_open(file, seq_ops);
466}
467
468static ssize_t
469event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
470          loff_t *ppos)
471{
472    struct ftrace_event_call *call = filp->private_data;
473    char *buf;
474
475    if (call->flags & TRACE_EVENT_FL_ENABLED)
476        buf = "1\n";
477    else
478        buf = "0\n";
479
480    return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
481}
482
483static ssize_t
484event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
485           loff_t *ppos)
486{
487    struct ftrace_event_call *call = filp->private_data;
488    char buf[64];
489    unsigned long val;
490    int ret;
491
492    if (cnt >= sizeof(buf))
493        return -EINVAL;
494
495    if (copy_from_user(&buf, ubuf, cnt))
496        return -EFAULT;
497
498    buf[cnt] = 0;
499
500    ret = strict_strtoul(buf, 10, &val);
501    if (ret < 0)
502        return ret;
503
504    ret = tracing_update_buffers();
505    if (ret < 0)
506        return ret;
507
508    switch (val) {
509    case 0:
510    case 1:
511        mutex_lock(&event_mutex);
512        ret = ftrace_event_enable_disable(call, val);
513        mutex_unlock(&event_mutex);
514        break;
515
516    default:
517        return -EINVAL;
518    }
519
520    *ppos += cnt;
521
522    return ret ? ret : cnt;
523}
524
525static ssize_t
526system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
527           loff_t *ppos)
528{
529    const char set_to_char[4] = { '?', '0', '1', 'X' };
530    const char *system = filp->private_data;
531    struct ftrace_event_call *call;
532    char buf[2];
533    int set = 0;
534    int ret;
535
536    mutex_lock(&event_mutex);
537    list_for_each_entry(call, &ftrace_events, list) {
538        if (!call->name || !call->class || !call->class->reg)
539            continue;
540
541        if (system && strcmp(call->class->system, system) != 0)
542            continue;
543
544        /*
545         * We need to find out if all the events are set
546         * or if all events or cleared, or if we have
547         * a mixture.
548         */
549        set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
550
551        /*
552         * If we have a mixture, no need to look further.
553         */
554        if (set == 3)
555            break;
556    }
557    mutex_unlock(&event_mutex);
558
559    buf[0] = set_to_char[set];
560    buf[1] = '\n';
561
562    ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
563
564    return ret;
565}
566
567static ssize_t
568system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
569            loff_t *ppos)
570{
571    const char *system = filp->private_data;
572    unsigned long val;
573    char buf[64];
574    ssize_t ret;
575
576    if (cnt >= sizeof(buf))
577        return -EINVAL;
578
579    if (copy_from_user(&buf, ubuf, cnt))
580        return -EFAULT;
581
582    buf[cnt] = 0;
583
584    ret = strict_strtoul(buf, 10, &val);
585    if (ret < 0)
586        return ret;
587
588    ret = tracing_update_buffers();
589    if (ret < 0)
590        return ret;
591
592    if (val != 0 && val != 1)
593        return -EINVAL;
594
595    ret = __ftrace_set_clr_event(NULL, system, NULL, val);
596    if (ret)
597        goto out;
598
599    ret = cnt;
600
601out:
602    *ppos += cnt;
603
604    return ret;
605}
606
607enum {
608    FORMAT_HEADER = 1,
609    FORMAT_FIELD_SEPERATOR = 2,
610    FORMAT_PRINTFMT = 3,
611};
612
613static void *f_next(struct seq_file *m, void *v, loff_t *pos)
614{
615    struct ftrace_event_call *call = m->private;
616    struct ftrace_event_field *field;
617    struct list_head *common_head = &ftrace_common_fields;
618    struct list_head *head = trace_get_fields(call);
619
620    (*pos)++;
621
622    switch ((unsigned long)v) {
623    case FORMAT_HEADER:
624        if (unlikely(list_empty(common_head)))
625            return NULL;
626
627        field = list_entry(common_head->prev,
628                   struct ftrace_event_field, link);
629        return field;
630
631    case FORMAT_FIELD_SEPERATOR:
632        if (unlikely(list_empty(head)))
633            return NULL;
634
635        field = list_entry(head->prev, struct ftrace_event_field, link);
636        return field;
637
638    case FORMAT_PRINTFMT:
639        /* all done */
640        return NULL;
641    }
642
643    field = v;
644    if (field->link.prev == common_head)
645        return (void *)FORMAT_FIELD_SEPERATOR;
646    else if (field->link.prev == head)
647        return (void *)FORMAT_PRINTFMT;
648
649    field = list_entry(field->link.prev, struct ftrace_event_field, link);
650
651    return field;
652}
653
654static void *f_start(struct seq_file *m, loff_t *pos)
655{
656    loff_t l = 0;
657    void *p;
658
659    /* Start by showing the header */
660    if (!*pos)
661        return (void *)FORMAT_HEADER;
662
663    p = (void *)FORMAT_HEADER;
664    do {
665        p = f_next(m, p, &l);
666    } while (p && l < *pos);
667
668    return p;
669}
670
671static int f_show(struct seq_file *m, void *v)
672{
673    struct ftrace_event_call *call = m->private;
674    struct ftrace_event_field *field;
675    const char *array_descriptor;
676
677    switch ((unsigned long)v) {
678    case FORMAT_HEADER:
679        seq_printf(m, "name: %s\n", call->name);
680        seq_printf(m, "ID: %d\n", call->event.type);
681        seq_printf(m, "format:\n");
682        return 0;
683
684    case FORMAT_FIELD_SEPERATOR:
685        seq_putc(m, '\n');
686        return 0;
687
688    case FORMAT_PRINTFMT:
689        seq_printf(m, "\nprint fmt: %s\n",
690               call->print_fmt);
691        return 0;
692    }
693
694    field = v;
695
696    /*
697     * Smartly shows the array type(except dynamic array).
698     * Normal:
699     * field:TYPE VAR
700     * If TYPE := TYPE[LEN], it is shown:
701     * field:TYPE VAR[LEN]
702     */
703    array_descriptor = strchr(field->type, '[');
704
705    if (!strncmp(field->type, "__data_loc", 10))
706        array_descriptor = NULL;
707
708    if (!array_descriptor)
709        seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
710               field->type, field->name, field->offset,
711               field->size, !!field->is_signed);
712    else
713        seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
714               (int)(array_descriptor - field->type),
715               field->type, field->name,
716               array_descriptor, field->offset,
717               field->size, !!field->is_signed);
718
719    return 0;
720}
721
722static void f_stop(struct seq_file *m, void *p)
723{
724}
725
726static const struct seq_operations trace_format_seq_ops = {
727    .start = f_start,
728    .next = f_next,
729    .stop = f_stop,
730    .show = f_show,
731};
732
733static int trace_format_open(struct inode *inode, struct file *file)
734{
735    struct ftrace_event_call *call = inode->i_private;
736    struct seq_file *m;
737    int ret;
738
739    ret = seq_open(file, &trace_format_seq_ops);
740    if (ret < 0)
741        return ret;
742
743    m = file->private_data;
744    m->private = call;
745
746    return 0;
747}
748
749static ssize_t
750event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
751{
752    struct ftrace_event_call *call = filp->private_data;
753    struct trace_seq *s;
754    int r;
755
756    if (*ppos)
757        return 0;
758
759    s = kmalloc(sizeof(*s), GFP_KERNEL);
760    if (!s)
761        return -ENOMEM;
762
763    trace_seq_init(s);
764    trace_seq_printf(s, "%d\n", call->event.type);
765
766    r = simple_read_from_buffer(ubuf, cnt, ppos,
767                    s->buffer, s->len);
768    kfree(s);
769    return r;
770}
771
772static ssize_t
773event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
774          loff_t *ppos)
775{
776    struct ftrace_event_call *call = filp->private_data;
777    struct trace_seq *s;
778    int r;
779
780    if (*ppos)
781        return 0;
782
783    s = kmalloc(sizeof(*s), GFP_KERNEL);
784    if (!s)
785        return -ENOMEM;
786
787    trace_seq_init(s);
788
789    print_event_filter(call, s);
790    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
791
792    kfree(s);
793
794    return r;
795}
796
797static ssize_t
798event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
799           loff_t *ppos)
800{
801    struct ftrace_event_call *call = filp->private_data;
802    char *buf;
803    int err;
804
805    if (cnt >= PAGE_SIZE)
806        return -EINVAL;
807
808    buf = (char *)__get_free_page(GFP_TEMPORARY);
809    if (!buf)
810        return -ENOMEM;
811
812    if (copy_from_user(buf, ubuf, cnt)) {
813        free_page((unsigned long) buf);
814        return -EFAULT;
815    }
816    buf[cnt] = '\0';
817
818    err = apply_event_filter(call, buf);
819    free_page((unsigned long) buf);
820    if (err < 0)
821        return err;
822
823    *ppos += cnt;
824
825    return cnt;
826}
827
828static ssize_t
829subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
830              loff_t *ppos)
831{
832    struct event_subsystem *system = filp->private_data;
833    struct trace_seq *s;
834    int r;
835
836    if (*ppos)
837        return 0;
838
839    s = kmalloc(sizeof(*s), GFP_KERNEL);
840    if (!s)
841        return -ENOMEM;
842
843    trace_seq_init(s);
844
845    print_subsystem_event_filter(system, s);
846    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
847
848    kfree(s);
849
850    return r;
851}
852
853static ssize_t
854subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
855               loff_t *ppos)
856{
857    struct event_subsystem *system = filp->private_data;
858    char *buf;
859    int err;
860
861    if (cnt >= PAGE_SIZE)
862        return -EINVAL;
863
864    buf = (char *)__get_free_page(GFP_TEMPORARY);
865    if (!buf)
866        return -ENOMEM;
867
868    if (copy_from_user(buf, ubuf, cnt)) {
869        free_page((unsigned long) buf);
870        return -EFAULT;
871    }
872    buf[cnt] = '\0';
873
874    err = apply_subsystem_event_filter(system, buf);
875    free_page((unsigned long) buf);
876    if (err < 0)
877        return err;
878
879    *ppos += cnt;
880
881    return cnt;
882}
883
884static ssize_t
885show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
886{
887    int (*func)(struct trace_seq *s) = filp->private_data;
888    struct trace_seq *s;
889    int r;
890
891    if (*ppos)
892        return 0;
893
894    s = kmalloc(sizeof(*s), GFP_KERNEL);
895    if (!s)
896        return -ENOMEM;
897
898    trace_seq_init(s);
899
900    func(s);
901    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
902
903    kfree(s);
904
905    return r;
906}
907
908static const struct seq_operations show_event_seq_ops = {
909    .start = t_start,
910    .next = t_next,
911    .show = t_show,
912    .stop = t_stop,
913};
914
915static const struct seq_operations show_set_event_seq_ops = {
916    .start = s_start,
917    .next = s_next,
918    .show = t_show,
919    .stop = t_stop,
920};
921
922static const struct file_operations ftrace_avail_fops = {
923    .open = ftrace_event_seq_open,
924    .read = seq_read,
925    .llseek = seq_lseek,
926    .release = seq_release,
927};
928
929static const struct file_operations ftrace_set_event_fops = {
930    .open = ftrace_event_seq_open,
931    .read = seq_read,
932    .write = ftrace_event_write,
933    .llseek = seq_lseek,
934    .release = seq_release,
935};
936
937static const struct file_operations ftrace_enable_fops = {
938    .open = tracing_open_generic,
939    .read = event_enable_read,
940    .write = event_enable_write,
941    .llseek = default_llseek,
942};
943
944static const struct file_operations ftrace_event_format_fops = {
945    .open = trace_format_open,
946    .read = seq_read,
947    .llseek = seq_lseek,
948    .release = seq_release,
949};
950
951static const struct file_operations ftrace_event_id_fops = {
952    .open = tracing_open_generic,
953    .read = event_id_read,
954    .llseek = default_llseek,
955};
956
957static const struct file_operations ftrace_event_filter_fops = {
958    .open = tracing_open_generic,
959    .read = event_filter_read,
960    .write = event_filter_write,
961    .llseek = default_llseek,
962};
963
964static const struct file_operations ftrace_subsystem_filter_fops = {
965    .open = tracing_open_generic,
966    .read = subsystem_filter_read,
967    .write = subsystem_filter_write,
968    .llseek = default_llseek,
969};
970
971static const struct file_operations ftrace_system_enable_fops = {
972    .open = tracing_open_generic,
973    .read = system_enable_read,
974    .write = system_enable_write,
975    .llseek = default_llseek,
976};
977
978static const struct file_operations ftrace_show_header_fops = {
979    .open = tracing_open_generic,
980    .read = show_header,
981    .llseek = default_llseek,
982};
983
984static struct dentry *event_trace_events_dir(void)
985{
986    static struct dentry *d_tracer;
987    static struct dentry *d_events;
988
989    if (d_events)
990        return d_events;
991
992    d_tracer = tracing_init_dentry();
993    if (!d_tracer)
994        return NULL;
995
996    d_events = debugfs_create_dir("events", d_tracer);
997    if (!d_events)
998        pr_warning("Could not create debugfs "
999               "'events' directory\n");
1000
1001    return d_events;
1002}
1003
1004static LIST_HEAD(event_subsystems);
1005
1006static struct dentry *
1007event_subsystem_dir(const char *name, struct dentry *d_events)
1008{
1009    struct event_subsystem *system;
1010    struct dentry *entry;
1011
1012    /* First see if we did not already create this dir */
1013    list_for_each_entry(system, &event_subsystems, list) {
1014        if (strcmp(system->name, name) == 0) {
1015            system->nr_events++;
1016            return system->entry;
1017        }
1018    }
1019
1020    /* need to create new entry */
1021    system = kmalloc(sizeof(*system), GFP_KERNEL);
1022    if (!system) {
1023        pr_warning("No memory to create event subsystem %s\n",
1024               name);
1025        return d_events;
1026    }
1027
1028    system->entry = debugfs_create_dir(name, d_events);
1029    if (!system->entry) {
1030        pr_warning("Could not create event subsystem %s\n",
1031               name);
1032        kfree(system);
1033        return d_events;
1034    }
1035
1036    system->nr_events = 1;
1037    system->name = kstrdup(name, GFP_KERNEL);
1038    if (!system->name) {
1039        debugfs_remove(system->entry);
1040        kfree(system);
1041        return d_events;
1042    }
1043
1044    list_add(&system->list, &event_subsystems);
1045
1046    system->filter = NULL;
1047
1048    system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1049    if (!system->filter) {
1050        pr_warning("Could not allocate filter for subsystem "
1051               "'%s'\n", name);
1052        return system->entry;
1053    }
1054
1055    entry = debugfs_create_file("filter", 0644, system->entry, system,
1056                    &ftrace_subsystem_filter_fops);
1057    if (!entry) {
1058        kfree(system->filter);
1059        system->filter = NULL;
1060        pr_warning("Could not create debugfs "
1061               "'%s/filter' entry\n", name);
1062    }
1063
1064    trace_create_file("enable", 0644, system->entry,
1065              (void *)system->name,
1066              &ftrace_system_enable_fops);
1067
1068    return system->entry;
1069}
1070
1071static int
1072event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1073         const struct file_operations *id,
1074         const struct file_operations *enable,
1075         const struct file_operations *filter,
1076         const struct file_operations *format)
1077{
1078    struct list_head *head;
1079    int ret;
1080
1081    /*
1082     * If the trace point header did not define TRACE_SYSTEM
1083     * then the system would be called "TRACE_SYSTEM".
1084     */
1085    if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1086        d_events = event_subsystem_dir(call->class->system, d_events);
1087
1088    call->dir = debugfs_create_dir(call->name, d_events);
1089    if (!call->dir) {
1090        pr_warning("Could not create debugfs "
1091               "'%s' directory\n", call->name);
1092        return -1;
1093    }
1094
1095    if (call->class->reg)
1096        trace_create_file("enable", 0644, call->dir, call,
1097                  enable);
1098
1099#ifdef CONFIG_PERF_EVENTS
1100    if (call->event.type && call->class->reg)
1101        trace_create_file("id", 0444, call->dir, call,
1102                   id);
1103#endif
1104
1105    /*
1106     * Other events may have the same class. Only update
1107     * the fields if they are not already defined.
1108     */
1109    head = trace_get_fields(call);
1110    if (list_empty(head)) {
1111        ret = call->class->define_fields(call);
1112        if (ret < 0) {
1113            pr_warning("Could not initialize trace point"
1114                   " events/%s\n", call->name);
1115            return ret;
1116        }
1117    }
1118    trace_create_file("filter", 0644, call->dir, call,
1119              filter);
1120
1121    trace_create_file("format", 0444, call->dir, call,
1122              format);
1123
1124    return 0;
1125}
1126
1127static int
1128__trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1129               const struct file_operations *id,
1130               const struct file_operations *enable,
1131               const struct file_operations *filter,
1132               const struct file_operations *format)
1133{
1134    struct dentry *d_events;
1135    int ret;
1136
1137    /* The linker may leave blanks */
1138    if (!call->name)
1139        return -EINVAL;
1140
1141    if (call->class->raw_init) {
1142        ret = call->class->raw_init(call);
1143        if (ret < 0) {
1144            if (ret != -ENOSYS)
1145                pr_warning("Could not initialize trace events/%s\n",
1146                       call->name);
1147            return ret;
1148        }
1149    }
1150
1151    d_events = event_trace_events_dir();
1152    if (!d_events)
1153        return -ENOENT;
1154
1155    ret = event_create_dir(call, d_events, id, enable, filter, format);
1156    if (!ret)
1157        list_add(&call->list, &ftrace_events);
1158    call->mod = mod;
1159
1160    return ret;
1161}
1162
1163/* Add an additional event_call dynamically */
1164int trace_add_event_call(struct ftrace_event_call *call)
1165{
1166    int ret;
1167    mutex_lock(&event_mutex);
1168    ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1169                     &ftrace_enable_fops,
1170                     &ftrace_event_filter_fops,
1171                     &ftrace_event_format_fops);
1172    mutex_unlock(&event_mutex);
1173    return ret;
1174}
1175
1176static void remove_subsystem_dir(const char *name)
1177{
1178    struct event_subsystem *system;
1179
1180    if (strcmp(name, TRACE_SYSTEM) == 0)
1181        return;
1182
1183    list_for_each_entry(system, &event_subsystems, list) {
1184        if (strcmp(system->name, name) == 0) {
1185            if (!--system->nr_events) {
1186                struct event_filter *filter = system->filter;
1187
1188                debugfs_remove_recursive(system->entry);
1189                list_del(&system->list);
1190                if (filter) {
1191                    kfree(filter->filter_string);
1192                    kfree(filter);
1193                }
1194                kfree(system->name);
1195                kfree(system);
1196            }
1197            break;
1198        }
1199    }
1200}
1201
1202/*
1203 * Must be called under locking both of event_mutex and trace_event_mutex.
1204 */
1205static void __trace_remove_event_call(struct ftrace_event_call *call)
1206{
1207    ftrace_event_enable_disable(call, 0);
1208    if (call->event.funcs)
1209        __unregister_ftrace_event(&call->event);
1210    debugfs_remove_recursive(call->dir);
1211    list_del(&call->list);
1212    trace_destroy_fields(call);
1213    destroy_preds(call);
1214    remove_subsystem_dir(call->class->system);
1215}
1216
1217/* Remove an event_call */
1218void trace_remove_event_call(struct ftrace_event_call *call)
1219{
1220    mutex_lock(&event_mutex);
1221    down_write(&trace_event_mutex);
1222    __trace_remove_event_call(call);
1223    up_write(&trace_event_mutex);
1224    mutex_unlock(&event_mutex);
1225}
1226
1227#define for_each_event(event, start, end) \
1228    for (event = start; \
1229         (unsigned long)event < (unsigned long)end; \
1230         event++)
1231
1232#ifdef CONFIG_MODULES
1233
1234static LIST_HEAD(ftrace_module_file_list);
1235
1236/*
1237 * Modules must own their file_operations to keep up with
1238 * reference counting.
1239 */
1240struct ftrace_module_file_ops {
1241    struct list_head list;
1242    struct module *mod;
1243    struct file_operations id;
1244    struct file_operations enable;
1245    struct file_operations format;
1246    struct file_operations filter;
1247};
1248
1249static struct ftrace_module_file_ops *
1250trace_create_file_ops(struct module *mod)
1251{
1252    struct ftrace_module_file_ops *file_ops;
1253
1254    /*
1255     * This is a bit of a PITA. To allow for correct reference
1256     * counting, modules must "own" their file_operations.
1257     * To do this, we allocate the file operations that will be
1258     * used in the event directory.
1259     */
1260
1261    file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1262    if (!file_ops)
1263        return NULL;
1264
1265    file_ops->mod = mod;
1266
1267    file_ops->id = ftrace_event_id_fops;
1268    file_ops->id.owner = mod;
1269
1270    file_ops->enable = ftrace_enable_fops;
1271    file_ops->enable.owner = mod;
1272
1273    file_ops->filter = ftrace_event_filter_fops;
1274    file_ops->filter.owner = mod;
1275
1276    file_ops->format = ftrace_event_format_fops;
1277    file_ops->format.owner = mod;
1278
1279    list_add(&file_ops->list, &ftrace_module_file_list);
1280
1281    return file_ops;
1282}
1283
1284static void trace_module_add_events(struct module *mod)
1285{
1286    struct ftrace_module_file_ops *file_ops = NULL;
1287    struct ftrace_event_call **call, **start, **end;
1288
1289    start = mod->trace_events;
1290    end = mod->trace_events + mod->num_trace_events;
1291
1292    if (start == end)
1293        return;
1294
1295    file_ops = trace_create_file_ops(mod);
1296    if (!file_ops)
1297        return;
1298
1299    for_each_event(call, start, end) {
1300        __trace_add_event_call(*call, mod,
1301                       &file_ops->id, &file_ops->enable,
1302                       &file_ops->filter, &file_ops->format);
1303    }
1304}
1305
1306static void trace_module_remove_events(struct module *mod)
1307{
1308    struct ftrace_module_file_ops *file_ops;
1309    struct ftrace_event_call *call, *p;
1310    bool found = false;
1311
1312    down_write(&trace_event_mutex);
1313    list_for_each_entry_safe(call, p, &ftrace_events, list) {
1314        if (call->mod == mod) {
1315            found = true;
1316            __trace_remove_event_call(call);
1317        }
1318    }
1319
1320    /* Now free the file_operations */
1321    list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1322        if (file_ops->mod == mod)
1323            break;
1324    }
1325    if (&file_ops->list != &ftrace_module_file_list) {
1326        list_del(&file_ops->list);
1327        kfree(file_ops);
1328    }
1329
1330    /*
1331     * It is safest to reset the ring buffer if the module being unloaded
1332     * registered any events.
1333     */
1334    if (found)
1335        tracing_reset_current_online_cpus();
1336    up_write(&trace_event_mutex);
1337}
1338
1339static int trace_module_notify(struct notifier_block *self,
1340                   unsigned long val, void *data)
1341{
1342    struct module *mod = data;
1343
1344    mutex_lock(&event_mutex);
1345    switch (val) {
1346    case MODULE_STATE_COMING:
1347        trace_module_add_events(mod);
1348        break;
1349    case MODULE_STATE_GOING:
1350        trace_module_remove_events(mod);
1351        break;
1352    }
1353    mutex_unlock(&event_mutex);
1354
1355    return 0;
1356}
1357#else
1358static int trace_module_notify(struct notifier_block *self,
1359                   unsigned long val, void *data)
1360{
1361    return 0;
1362}
1363#endif /* CONFIG_MODULES */
1364
1365static struct notifier_block trace_module_nb = {
1366    .notifier_call = trace_module_notify,
1367    .priority = 0,
1368};
1369
1370extern struct ftrace_event_call *__start_ftrace_events[];
1371extern struct ftrace_event_call *__stop_ftrace_events[];
1372
1373static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1374
1375static __init int setup_trace_event(char *str)
1376{
1377    strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1378    ring_buffer_expanded = 1;
1379    tracing_selftest_disabled = 1;
1380
1381    return 1;
1382}
1383__setup("trace_event=", setup_trace_event);
1384
1385static __init int event_trace_init(void)
1386{
1387    struct ftrace_event_call **call;
1388    struct dentry *d_tracer;
1389    struct dentry *entry;
1390    struct dentry *d_events;
1391    int ret;
1392    char *buf = bootup_event_buf;
1393    char *token;
1394
1395    d_tracer = tracing_init_dentry();
1396    if (!d_tracer)
1397        return 0;
1398
1399    entry = debugfs_create_file("available_events", 0444, d_tracer,
1400                    (void *)&show_event_seq_ops,
1401                    &ftrace_avail_fops);
1402    if (!entry)
1403        pr_warning("Could not create debugfs "
1404               "'available_events' entry\n");
1405
1406    entry = debugfs_create_file("set_event", 0644, d_tracer,
1407                    (void *)&show_set_event_seq_ops,
1408                    &ftrace_set_event_fops);
1409    if (!entry)
1410        pr_warning("Could not create debugfs "
1411               "'set_event' entry\n");
1412
1413    d_events = event_trace_events_dir();
1414    if (!d_events)
1415        return 0;
1416
1417    /* ring buffer internal formats */
1418    trace_create_file("header_page", 0444, d_events,
1419              ring_buffer_print_page_header,
1420              &ftrace_show_header_fops);
1421
1422    trace_create_file("header_event", 0444, d_events,
1423              ring_buffer_print_entry_header,
1424              &ftrace_show_header_fops);
1425
1426    trace_create_file("enable", 0644, d_events,
1427              NULL, &ftrace_system_enable_fops);
1428
1429    if (trace_define_common_fields())
1430        pr_warning("tracing: Failed to allocate common fields");
1431
1432    for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1433        __trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
1434                       &ftrace_enable_fops,
1435                       &ftrace_event_filter_fops,
1436                       &ftrace_event_format_fops);
1437    }
1438
1439    while (true) {
1440        token = strsep(&buf, ",");
1441
1442        if (!token)
1443            break;
1444        if (!*token)
1445            continue;
1446
1447        ret = ftrace_set_clr_event(token, 1);
1448        if (ret)
1449            pr_warning("Failed to enable trace event: %s\n", token);
1450    }
1451
1452    ret = register_module_notifier(&trace_module_nb);
1453    if (ret)
1454        pr_warning("Failed to register trace events module notifier\n");
1455
1456    return 0;
1457}
1458fs_initcall(event_trace_init);
1459
1460#ifdef CONFIG_FTRACE_STARTUP_TEST
1461
1462static DEFINE_SPINLOCK(test_spinlock);
1463static DEFINE_SPINLOCK(test_spinlock_irq);
1464static DEFINE_MUTEX(test_mutex);
1465
1466static __init void test_work(struct work_struct *dummy)
1467{
1468    spin_lock(&test_spinlock);
1469    spin_lock_irq(&test_spinlock_irq);
1470    udelay(1);
1471    spin_unlock_irq(&test_spinlock_irq);
1472    spin_unlock(&test_spinlock);
1473
1474    mutex_lock(&test_mutex);
1475    msleep(1);
1476    mutex_unlock(&test_mutex);
1477}
1478
1479static __init int event_test_thread(void *unused)
1480{
1481    void *test_malloc;
1482
1483    test_malloc = kmalloc(1234, GFP_KERNEL);
1484    if (!test_malloc)
1485        pr_info("failed to kmalloc\n");
1486
1487    schedule_on_each_cpu(test_work);
1488
1489    kfree(test_malloc);
1490
1491    set_current_state(TASK_INTERRUPTIBLE);
1492    while (!kthread_should_stop())
1493        schedule();
1494
1495    return 0;
1496}
1497
1498/*
1499 * Do various things that may trigger events.
1500 */
1501static __init void event_test_stuff(void)
1502{
1503    struct task_struct *test_thread;
1504
1505    test_thread = kthread_run(event_test_thread, NULL, "test-events");
1506    msleep(1);
1507    kthread_stop(test_thread);
1508}
1509
1510/*
1511 * For every trace event defined, we will test each trace point separately,
1512 * and then by groups, and finally all trace points.
1513 */
1514static __init void event_trace_self_tests(void)
1515{
1516    struct ftrace_event_call *call;
1517    struct event_subsystem *system;
1518    int ret;
1519
1520    pr_info("Running tests on trace events:\n");
1521
1522    list_for_each_entry(call, &ftrace_events, list) {
1523
1524        /* Only test those that have a probe */
1525        if (!call->class || !call->class->probe)
1526            continue;
1527
1528/*
1529 * Testing syscall events here is pretty useless, but
1530 * we still do it if configured. But this is time consuming.
1531 * What we really need is a user thread to perform the
1532 * syscalls as we test.
1533 */
1534#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1535        if (call->class->system &&
1536            strcmp(call->class->system, "syscalls") == 0)
1537            continue;
1538#endif
1539
1540        pr_info("Testing event %s: ", call->name);
1541
1542        /*
1543         * If an event is already enabled, someone is using
1544         * it and the self test should not be on.
1545         */
1546        if (call->flags & TRACE_EVENT_FL_ENABLED) {
1547            pr_warning("Enabled event during self test!\n");
1548            WARN_ON_ONCE(1);
1549            continue;
1550        }
1551
1552        ftrace_event_enable_disable(call, 1);
1553        event_test_stuff();
1554        ftrace_event_enable_disable(call, 0);
1555
1556        pr_cont("OK\n");
1557    }
1558
1559    /* Now test at the sub system level */
1560
1561    pr_info("Running tests on trace event systems:\n");
1562
1563    list_for_each_entry(system, &event_subsystems, list) {
1564
1565        /* the ftrace system is special, skip it */
1566        if (strcmp(system->name, "ftrace") == 0)
1567            continue;
1568
1569        pr_info("Testing event system %s: ", system->name);
1570
1571        ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1572        if (WARN_ON_ONCE(ret)) {
1573            pr_warning("error enabling system %s\n",
1574                   system->name);
1575            continue;
1576        }
1577
1578        event_test_stuff();
1579
1580        ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1581        if (WARN_ON_ONCE(ret))
1582            pr_warning("error disabling system %s\n",
1583                   system->name);
1584
1585        pr_cont("OK\n");
1586    }
1587
1588    /* Test with all events enabled */
1589
1590    pr_info("Running tests on all trace events:\n");
1591    pr_info("Testing all events: ");
1592
1593    ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1594    if (WARN_ON_ONCE(ret)) {
1595        pr_warning("error enabling all events\n");
1596        return;
1597    }
1598
1599    event_test_stuff();
1600
1601    /* reset sysname */
1602    ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1603    if (WARN_ON_ONCE(ret)) {
1604        pr_warning("error disabling all events\n");
1605        return;
1606    }
1607
1608    pr_cont("OK\n");
1609}
1610
1611#ifdef CONFIG_FUNCTION_TRACER
1612
1613static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1614
1615static void
1616function_test_events_call(unsigned long ip, unsigned long parent_ip)
1617{
1618    struct ring_buffer_event *event;
1619    struct ring_buffer *buffer;
1620    struct ftrace_entry *entry;
1621    unsigned long flags;
1622    long disabled;
1623    int cpu;
1624    int pc;
1625
1626    pc = preempt_count();
1627    preempt_disable_notrace();
1628    cpu = raw_smp_processor_id();
1629    disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1630
1631    if (disabled != 1)
1632        goto out;
1633
1634    local_save_flags(flags);
1635
1636    event = trace_current_buffer_lock_reserve(&buffer,
1637                          TRACE_FN, sizeof(*entry),
1638                          flags, pc);
1639    if (!event)
1640        goto out;
1641    entry = ring_buffer_event_data(event);
1642    entry->ip = ip;
1643    entry->parent_ip = parent_ip;
1644
1645    trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1646
1647 out:
1648    atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1649    preempt_enable_notrace();
1650}
1651
1652static struct ftrace_ops trace_ops __initdata =
1653{
1654    .func = function_test_events_call,
1655};
1656
1657static __init void event_trace_self_test_with_function(void)
1658{
1659    register_ftrace_function(&trace_ops);
1660    pr_info("Running tests again, along with the function tracer\n");
1661    event_trace_self_tests();
1662    unregister_ftrace_function(&trace_ops);
1663}
1664#else
1665static __init void event_trace_self_test_with_function(void)
1666{
1667}
1668#endif
1669
1670static __init int event_trace_self_tests_init(void)
1671{
1672    if (!tracing_selftest_disabled) {
1673        event_trace_self_tests();
1674        event_trace_self_test_with_function();
1675    }
1676
1677    return 0;
1678}
1679
1680late_initcall(event_trace_self_tests_init);
1681
1682#endif
1683

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