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, padding);
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}
329EXPORT_SYMBOL_GPL(trace_set_clr_event);
330
331/* 128 should be much more than enough */
332#define EVENT_BUF_SIZE 127
333
334static ssize_t
335ftrace_event_write(struct file *file, const char __user *ubuf,
336           size_t cnt, loff_t *ppos)
337{
338    struct trace_parser parser;
339    ssize_t read, ret;
340
341    if (!cnt)
342        return 0;
343
344    ret = tracing_update_buffers();
345    if (ret < 0)
346        return ret;
347
348    if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
349        return -ENOMEM;
350
351    read = trace_get_user(&parser, ubuf, cnt, ppos);
352
353    if (read >= 0 && trace_parser_loaded((&parser))) {
354        int set = 1;
355
356        if (*parser.buffer == '!')
357            set = 0;
358
359        parser.buffer[parser.idx] = 0;
360
361        ret = ftrace_set_clr_event(parser.buffer + !set, set);
362        if (ret)
363            goto out_put;
364    }
365
366    ret = read;
367
368 out_put:
369    trace_parser_put(&parser);
370
371    return ret;
372}
373
374static void *
375t_next(struct seq_file *m, void *v, loff_t *pos)
376{
377    struct ftrace_event_call *call = v;
378
379    (*pos)++;
380
381    list_for_each_entry_continue(call, &ftrace_events, list) {
382        /*
383         * The ftrace subsystem is for showing formats only.
384         * They can not be enabled or disabled via the event files.
385         */
386        if (call->class && call->class->reg)
387            return call;
388    }
389
390    return NULL;
391}
392
393static void *t_start(struct seq_file *m, loff_t *pos)
394{
395    struct ftrace_event_call *call;
396    loff_t l;
397
398    mutex_lock(&event_mutex);
399
400    call = list_entry(&ftrace_events, struct ftrace_event_call, list);
401    for (l = 0; l <= *pos; ) {
402        call = t_next(m, call, &l);
403        if (!call)
404            break;
405    }
406    return call;
407}
408
409static void *
410s_next(struct seq_file *m, void *v, loff_t *pos)
411{
412    struct ftrace_event_call *call = v;
413
414    (*pos)++;
415
416    list_for_each_entry_continue(call, &ftrace_events, list) {
417        if (call->flags & TRACE_EVENT_FL_ENABLED)
418            return call;
419    }
420
421    return NULL;
422}
423
424static void *s_start(struct seq_file *m, loff_t *pos)
425{
426    struct ftrace_event_call *call;
427    loff_t l;
428
429    mutex_lock(&event_mutex);
430
431    call = list_entry(&ftrace_events, struct ftrace_event_call, list);
432    for (l = 0; l <= *pos; ) {
433        call = s_next(m, call, &l);
434        if (!call)
435            break;
436    }
437    return call;
438}
439
440static int t_show(struct seq_file *m, void *v)
441{
442    struct ftrace_event_call *call = v;
443
444    if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
445        seq_printf(m, "%s:", call->class->system);
446    seq_printf(m, "%s\n", call->name);
447
448    return 0;
449}
450
451static void t_stop(struct seq_file *m, void *p)
452{
453    mutex_unlock(&event_mutex);
454}
455
456static int
457ftrace_event_seq_open(struct inode *inode, struct file *file)
458{
459    const struct seq_operations *seq_ops;
460
461    if ((file->f_mode & FMODE_WRITE) &&
462        (file->f_flags & O_TRUNC))
463        ftrace_clear_events();
464
465    seq_ops = inode->i_private;
466    return seq_open(file, seq_ops);
467}
468
469static ssize_t
470event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
471          loff_t *ppos)
472{
473    struct ftrace_event_call *call = filp->private_data;
474    char *buf;
475
476    if (call->flags & TRACE_EVENT_FL_ENABLED)
477        buf = "1\n";
478    else
479        buf = "0\n";
480
481    return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
482}
483
484static ssize_t
485event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
486           loff_t *ppos)
487{
488    struct ftrace_event_call *call = filp->private_data;
489    char buf[64];
490    unsigned long val;
491    int ret;
492
493    if (cnt >= sizeof(buf))
494        return -EINVAL;
495
496    if (copy_from_user(&buf, ubuf, cnt))
497        return -EFAULT;
498
499    buf[cnt] = 0;
500
501    ret = strict_strtoul(buf, 10, &val);
502    if (ret < 0)
503        return ret;
504
505    ret = tracing_update_buffers();
506    if (ret < 0)
507        return ret;
508
509    switch (val) {
510    case 0:
511    case 1:
512        mutex_lock(&event_mutex);
513        ret = ftrace_event_enable_disable(call, val);
514        mutex_unlock(&event_mutex);
515        break;
516
517    default:
518        return -EINVAL;
519    }
520
521    *ppos += cnt;
522
523    return ret ? ret : cnt;
524}
525
526static ssize_t
527system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
528           loff_t *ppos)
529{
530    const char set_to_char[4] = { '?', '0', '1', 'X' };
531    const char *system = filp->private_data;
532    struct ftrace_event_call *call;
533    char buf[2];
534    int set = 0;
535    int ret;
536
537    mutex_lock(&event_mutex);
538    list_for_each_entry(call, &ftrace_events, list) {
539        if (!call->name || !call->class || !call->class->reg)
540            continue;
541
542        if (system && strcmp(call->class->system, system) != 0)
543            continue;
544
545        /*
546         * We need to find out if all the events are set
547         * or if all events or cleared, or if we have
548         * a mixture.
549         */
550        set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
551
552        /*
553         * If we have a mixture, no need to look further.
554         */
555        if (set == 3)
556            break;
557    }
558    mutex_unlock(&event_mutex);
559
560    buf[0] = set_to_char[set];
561    buf[1] = '\n';
562
563    ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
564
565    return ret;
566}
567
568static ssize_t
569system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
570            loff_t *ppos)
571{
572    const char *system = filp->private_data;
573    unsigned long val;
574    char buf[64];
575    ssize_t ret;
576
577    if (cnt >= sizeof(buf))
578        return -EINVAL;
579
580    if (copy_from_user(&buf, ubuf, cnt))
581        return -EFAULT;
582
583    buf[cnt] = 0;
584
585    ret = strict_strtoul(buf, 10, &val);
586    if (ret < 0)
587        return ret;
588
589    ret = tracing_update_buffers();
590    if (ret < 0)
591        return ret;
592
593    if (val != 0 && val != 1)
594        return -EINVAL;
595
596    ret = __ftrace_set_clr_event(NULL, system, NULL, val);
597    if (ret)
598        goto out;
599
600    ret = cnt;
601
602out:
603    *ppos += cnt;
604
605    return ret;
606}
607
608enum {
609    FORMAT_HEADER = 1,
610    FORMAT_FIELD_SEPERATOR = 2,
611    FORMAT_PRINTFMT = 3,
612};
613
614static void *f_next(struct seq_file *m, void *v, loff_t *pos)
615{
616    struct ftrace_event_call *call = m->private;
617    struct ftrace_event_field *field;
618    struct list_head *common_head = &ftrace_common_fields;
619    struct list_head *head = trace_get_fields(call);
620
621    (*pos)++;
622
623    switch ((unsigned long)v) {
624    case FORMAT_HEADER:
625        if (unlikely(list_empty(common_head)))
626            return NULL;
627
628        field = list_entry(common_head->prev,
629                   struct ftrace_event_field, link);
630        return field;
631
632    case FORMAT_FIELD_SEPERATOR:
633        if (unlikely(list_empty(head)))
634            return NULL;
635
636        field = list_entry(head->prev, struct ftrace_event_field, link);
637        return field;
638
639    case FORMAT_PRINTFMT:
640        /* all done */
641        return NULL;
642    }
643
644    field = v;
645    if (field->link.prev == common_head)
646        return (void *)FORMAT_FIELD_SEPERATOR;
647    else if (field->link.prev == head)
648        return (void *)FORMAT_PRINTFMT;
649
650    field = list_entry(field->link.prev, struct ftrace_event_field, link);
651
652    return field;
653}
654
655static void *f_start(struct seq_file *m, loff_t *pos)
656{
657    loff_t l = 0;
658    void *p;
659
660    /* Start by showing the header */
661    if (!*pos)
662        return (void *)FORMAT_HEADER;
663
664    p = (void *)FORMAT_HEADER;
665    do {
666        p = f_next(m, p, &l);
667    } while (p && l < *pos);
668
669    return p;
670}
671
672static int f_show(struct seq_file *m, void *v)
673{
674    struct ftrace_event_call *call = m->private;
675    struct ftrace_event_field *field;
676    const char *array_descriptor;
677
678    switch ((unsigned long)v) {
679    case FORMAT_HEADER:
680        seq_printf(m, "name: %s\n", call->name);
681        seq_printf(m, "ID: %d\n", call->event.type);
682        seq_printf(m, "format:\n");
683        return 0;
684
685    case FORMAT_FIELD_SEPERATOR:
686        seq_putc(m, '\n');
687        return 0;
688
689    case FORMAT_PRINTFMT:
690        seq_printf(m, "\nprint fmt: %s\n",
691               call->print_fmt);
692        return 0;
693    }
694
695    field = v;
696
697    /*
698     * Smartly shows the array type(except dynamic array).
699     * Normal:
700     * field:TYPE VAR
701     * If TYPE := TYPE[LEN], it is shown:
702     * field:TYPE VAR[LEN]
703     */
704    array_descriptor = strchr(field->type, '[');
705
706    if (!strncmp(field->type, "__data_loc", 10))
707        array_descriptor = NULL;
708
709    if (!array_descriptor)
710        seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
711               field->type, field->name, field->offset,
712               field->size, !!field->is_signed);
713    else
714        seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
715               (int)(array_descriptor - field->type),
716               field->type, field->name,
717               array_descriptor, field->offset,
718               field->size, !!field->is_signed);
719
720    return 0;
721}
722
723static void f_stop(struct seq_file *m, void *p)
724{
725}
726
727static const struct seq_operations trace_format_seq_ops = {
728    .start = f_start,
729    .next = f_next,
730    .stop = f_stop,
731    .show = f_show,
732};
733
734static int trace_format_open(struct inode *inode, struct file *file)
735{
736    struct ftrace_event_call *call = inode->i_private;
737    struct seq_file *m;
738    int ret;
739
740    ret = seq_open(file, &trace_format_seq_ops);
741    if (ret < 0)
742        return ret;
743
744    m = file->private_data;
745    m->private = call;
746
747    return 0;
748}
749
750static ssize_t
751event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
752{
753    struct ftrace_event_call *call = filp->private_data;
754    struct trace_seq *s;
755    int r;
756
757    if (*ppos)
758        return 0;
759
760    s = kmalloc(sizeof(*s), GFP_KERNEL);
761    if (!s)
762        return -ENOMEM;
763
764    trace_seq_init(s);
765    trace_seq_printf(s, "%d\n", call->event.type);
766
767    r = simple_read_from_buffer(ubuf, cnt, ppos,
768                    s->buffer, s->len);
769    kfree(s);
770    return r;
771}
772
773static ssize_t
774event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
775          loff_t *ppos)
776{
777    struct ftrace_event_call *call = filp->private_data;
778    struct trace_seq *s;
779    int r;
780
781    if (*ppos)
782        return 0;
783
784    s = kmalloc(sizeof(*s), GFP_KERNEL);
785    if (!s)
786        return -ENOMEM;
787
788    trace_seq_init(s);
789
790    print_event_filter(call, s);
791    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
792
793    kfree(s);
794
795    return r;
796}
797
798static ssize_t
799event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
800           loff_t *ppos)
801{
802    struct ftrace_event_call *call = filp->private_data;
803    char *buf;
804    int err;
805
806    if (cnt >= PAGE_SIZE)
807        return -EINVAL;
808
809    buf = (char *)__get_free_page(GFP_TEMPORARY);
810    if (!buf)
811        return -ENOMEM;
812
813    if (copy_from_user(buf, ubuf, cnt)) {
814        free_page((unsigned long) buf);
815        return -EFAULT;
816    }
817    buf[cnt] = '\0';
818
819    err = apply_event_filter(call, buf);
820    free_page((unsigned long) buf);
821    if (err < 0)
822        return err;
823
824    *ppos += cnt;
825
826    return cnt;
827}
828
829static ssize_t
830subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
831              loff_t *ppos)
832{
833    struct event_subsystem *system = filp->private_data;
834    struct trace_seq *s;
835    int r;
836
837    if (*ppos)
838        return 0;
839
840    s = kmalloc(sizeof(*s), GFP_KERNEL);
841    if (!s)
842        return -ENOMEM;
843
844    trace_seq_init(s);
845
846    print_subsystem_event_filter(system, s);
847    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
848
849    kfree(s);
850
851    return r;
852}
853
854static ssize_t
855subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
856               loff_t *ppos)
857{
858    struct event_subsystem *system = filp->private_data;
859    char *buf;
860    int err;
861
862    if (cnt >= PAGE_SIZE)
863        return -EINVAL;
864
865    buf = (char *)__get_free_page(GFP_TEMPORARY);
866    if (!buf)
867        return -ENOMEM;
868
869    if (copy_from_user(buf, ubuf, cnt)) {
870        free_page((unsigned long) buf);
871        return -EFAULT;
872    }
873    buf[cnt] = '\0';
874
875    err = apply_subsystem_event_filter(system, buf);
876    free_page((unsigned long) buf);
877    if (err < 0)
878        return err;
879
880    *ppos += cnt;
881
882    return cnt;
883}
884
885static ssize_t
886show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
887{
888    int (*func)(struct trace_seq *s) = filp->private_data;
889    struct trace_seq *s;
890    int r;
891
892    if (*ppos)
893        return 0;
894
895    s = kmalloc(sizeof(*s), GFP_KERNEL);
896    if (!s)
897        return -ENOMEM;
898
899    trace_seq_init(s);
900
901    func(s);
902    r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
903
904    kfree(s);
905
906    return r;
907}
908
909static const struct seq_operations show_event_seq_ops = {
910    .start = t_start,
911    .next = t_next,
912    .show = t_show,
913    .stop = t_stop,
914};
915
916static const struct seq_operations show_set_event_seq_ops = {
917    .start = s_start,
918    .next = s_next,
919    .show = t_show,
920    .stop = t_stop,
921};
922
923static const struct file_operations ftrace_avail_fops = {
924    .open = ftrace_event_seq_open,
925    .read = seq_read,
926    .llseek = seq_lseek,
927    .release = seq_release,
928};
929
930static const struct file_operations ftrace_set_event_fops = {
931    .open = ftrace_event_seq_open,
932    .read = seq_read,
933    .write = ftrace_event_write,
934    .llseek = seq_lseek,
935    .release = seq_release,
936};
937
938static const struct file_operations ftrace_enable_fops = {
939    .open = tracing_open_generic,
940    .read = event_enable_read,
941    .write = event_enable_write,
942    .llseek = default_llseek,
943};
944
945static const struct file_operations ftrace_event_format_fops = {
946    .open = trace_format_open,
947    .read = seq_read,
948    .llseek = seq_lseek,
949    .release = seq_release,
950};
951
952static const struct file_operations ftrace_event_id_fops = {
953    .open = tracing_open_generic,
954    .read = event_id_read,
955    .llseek = default_llseek,
956};
957
958static const struct file_operations ftrace_event_filter_fops = {
959    .open = tracing_open_generic,
960    .read = event_filter_read,
961    .write = event_filter_write,
962    .llseek = default_llseek,
963};
964
965static const struct file_operations ftrace_subsystem_filter_fops = {
966    .open = tracing_open_generic,
967    .read = subsystem_filter_read,
968    .write = subsystem_filter_write,
969    .llseek = default_llseek,
970};
971
972static const struct file_operations ftrace_system_enable_fops = {
973    .open = tracing_open_generic,
974    .read = system_enable_read,
975    .write = system_enable_write,
976    .llseek = default_llseek,
977};
978
979static const struct file_operations ftrace_show_header_fops = {
980    .open = tracing_open_generic,
981    .read = show_header,
982    .llseek = default_llseek,
983};
984
985static struct dentry *event_trace_events_dir(void)
986{
987    static struct dentry *d_tracer;
988    static struct dentry *d_events;
989
990    if (d_events)
991        return d_events;
992
993    d_tracer = tracing_init_dentry();
994    if (!d_tracer)
995        return NULL;
996
997    d_events = debugfs_create_dir("events", d_tracer);
998    if (!d_events)
999        pr_warning("Could not create debugfs "
1000               "'events' directory\n");
1001
1002    return d_events;
1003}
1004
1005static LIST_HEAD(event_subsystems);
1006
1007static struct dentry *
1008event_subsystem_dir(const char *name, struct dentry *d_events)
1009{
1010    struct event_subsystem *system;
1011    struct dentry *entry;
1012
1013    /* First see if we did not already create this dir */
1014    list_for_each_entry(system, &event_subsystems, list) {
1015        if (strcmp(system->name, name) == 0) {
1016            system->nr_events++;
1017            return system->entry;
1018        }
1019    }
1020
1021    /* need to create new entry */
1022    system = kmalloc(sizeof(*system), GFP_KERNEL);
1023    if (!system) {
1024        pr_warning("No memory to create event subsystem %s\n",
1025               name);
1026        return d_events;
1027    }
1028
1029    system->entry = debugfs_create_dir(name, d_events);
1030    if (!system->entry) {
1031        pr_warning("Could not create event subsystem %s\n",
1032               name);
1033        kfree(system);
1034        return d_events;
1035    }
1036
1037    system->nr_events = 1;
1038    system->name = kstrdup(name, GFP_KERNEL);
1039    if (!system->name) {
1040        debugfs_remove(system->entry);
1041        kfree(system);
1042        return d_events;
1043    }
1044
1045    list_add(&system->list, &event_subsystems);
1046
1047    system->filter = NULL;
1048
1049    system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1050    if (!system->filter) {
1051        pr_warning("Could not allocate filter for subsystem "
1052               "'%s'\n", name);
1053        return system->entry;
1054    }
1055
1056    entry = debugfs_create_file("filter", 0644, system->entry, system,
1057                    &ftrace_subsystem_filter_fops);
1058    if (!entry) {
1059        kfree(system->filter);
1060        system->filter = NULL;
1061        pr_warning("Could not create debugfs "
1062               "'%s/filter' entry\n", name);
1063    }
1064
1065    trace_create_file("enable", 0644, system->entry,
1066              (void *)system->name,
1067              &ftrace_system_enable_fops);
1068
1069    return system->entry;
1070}
1071
1072static int
1073event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1074         const struct file_operations *id,
1075         const struct file_operations *enable,
1076         const struct file_operations *filter,
1077         const struct file_operations *format)
1078{
1079    struct list_head *head;
1080    int ret;
1081
1082    /*
1083     * If the trace point header did not define TRACE_SYSTEM
1084     * then the system would be called "TRACE_SYSTEM".
1085     */
1086    if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1087        d_events = event_subsystem_dir(call->class->system, d_events);
1088
1089    call->dir = debugfs_create_dir(call->name, d_events);
1090    if (!call->dir) {
1091        pr_warning("Could not create debugfs "
1092               "'%s' directory\n", call->name);
1093        return -1;
1094    }
1095
1096    if (call->class->reg)
1097        trace_create_file("enable", 0644, call->dir, call,
1098                  enable);
1099
1100#ifdef CONFIG_PERF_EVENTS
1101    if (call->event.type && call->class->reg)
1102        trace_create_file("id", 0444, call->dir, call,
1103                   id);
1104#endif
1105
1106    /*
1107     * Other events may have the same class. Only update
1108     * the fields if they are not already defined.
1109     */
1110    head = trace_get_fields(call);
1111    if (list_empty(head)) {
1112        ret = call->class->define_fields(call);
1113        if (ret < 0) {
1114            pr_warning("Could not initialize trace point"
1115                   " events/%s\n", call->name);
1116            return ret;
1117        }
1118    }
1119    trace_create_file("filter", 0644, call->dir, call,
1120              filter);
1121
1122    trace_create_file("format", 0444, call->dir, call,
1123              format);
1124
1125    return 0;
1126}
1127
1128static int
1129__trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1130               const struct file_operations *id,
1131               const struct file_operations *enable,
1132               const struct file_operations *filter,
1133               const struct file_operations *format)
1134{
1135    struct dentry *d_events;
1136    int ret;
1137
1138    /* The linker may leave blanks */
1139    if (!call->name)
1140        return -EINVAL;
1141
1142    if (call->class->raw_init) {
1143        ret = call->class->raw_init(call);
1144        if (ret < 0) {
1145            if (ret != -ENOSYS)
1146                pr_warning("Could not initialize trace events/%s\n",
1147                       call->name);
1148            return ret;
1149        }
1150    }
1151
1152    d_events = event_trace_events_dir();
1153    if (!d_events)
1154        return -ENOENT;
1155
1156    ret = event_create_dir(call, d_events, id, enable, filter, format);
1157    if (!ret)
1158        list_add(&call->list, &ftrace_events);
1159    call->mod = mod;
1160
1161    return ret;
1162}
1163
1164/* Add an additional event_call dynamically */
1165int trace_add_event_call(struct ftrace_event_call *call)
1166{
1167    int ret;
1168    mutex_lock(&event_mutex);
1169    ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1170                     &ftrace_enable_fops,
1171                     &ftrace_event_filter_fops,
1172                     &ftrace_event_format_fops);
1173    mutex_unlock(&event_mutex);
1174    return ret;
1175}
1176
1177static void remove_subsystem_dir(const char *name)
1178{
1179    struct event_subsystem *system;
1180
1181    if (strcmp(name, TRACE_SYSTEM) == 0)
1182        return;
1183
1184    list_for_each_entry(system, &event_subsystems, list) {
1185        if (strcmp(system->name, name) == 0) {
1186            if (!--system->nr_events) {
1187                struct event_filter *filter = system->filter;
1188
1189                debugfs_remove_recursive(system->entry);
1190                list_del(&system->list);
1191                if (filter) {
1192                    kfree(filter->filter_string);
1193                    kfree(filter);
1194                }
1195                kfree(system->name);
1196                kfree(system);
1197            }
1198            break;
1199        }
1200    }
1201}
1202
1203/*
1204 * Must be called under locking both of event_mutex and trace_event_mutex.
1205 */
1206static void __trace_remove_event_call(struct ftrace_event_call *call)
1207{
1208    ftrace_event_enable_disable(call, 0);
1209    if (call->event.funcs)
1210        __unregister_ftrace_event(&call->event);
1211    debugfs_remove_recursive(call->dir);
1212    list_del(&call->list);
1213    trace_destroy_fields(call);
1214    destroy_preds(call);
1215    remove_subsystem_dir(call->class->system);
1216}
1217
1218/* Remove an event_call */
1219void trace_remove_event_call(struct ftrace_event_call *call)
1220{
1221    mutex_lock(&event_mutex);
1222    down_write(&trace_event_mutex);
1223    __trace_remove_event_call(call);
1224    up_write(&trace_event_mutex);
1225    mutex_unlock(&event_mutex);
1226}
1227
1228#define for_each_event(event, start, end) \
1229    for (event = start; \
1230         (unsigned long)event < (unsigned long)end; \
1231         event++)
1232
1233#ifdef CONFIG_MODULES
1234
1235static LIST_HEAD(ftrace_module_file_list);
1236
1237/*
1238 * Modules must own their file_operations to keep up with
1239 * reference counting.
1240 */
1241struct ftrace_module_file_ops {
1242    struct list_head list;
1243    struct module *mod;
1244    struct file_operations id;
1245    struct file_operations enable;
1246    struct file_operations format;
1247    struct file_operations filter;
1248};
1249
1250static struct ftrace_module_file_ops *
1251trace_create_file_ops(struct module *mod)
1252{
1253    struct ftrace_module_file_ops *file_ops;
1254
1255    /*
1256     * This is a bit of a PITA. To allow for correct reference
1257     * counting, modules must "own" their file_operations.
1258     * To do this, we allocate the file operations that will be
1259     * used in the event directory.
1260     */
1261
1262    file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1263    if (!file_ops)
1264        return NULL;
1265
1266    file_ops->mod = mod;
1267
1268    file_ops->id = ftrace_event_id_fops;
1269    file_ops->id.owner = mod;
1270
1271    file_ops->enable = ftrace_enable_fops;
1272    file_ops->enable.owner = mod;
1273
1274    file_ops->filter = ftrace_event_filter_fops;
1275    file_ops->filter.owner = mod;
1276
1277    file_ops->format = ftrace_event_format_fops;
1278    file_ops->format.owner = mod;
1279
1280    list_add(&file_ops->list, &ftrace_module_file_list);
1281
1282    return file_ops;
1283}
1284
1285static void trace_module_add_events(struct module *mod)
1286{
1287    struct ftrace_module_file_ops *file_ops = NULL;
1288    struct ftrace_event_call **call, **start, **end;
1289
1290    start = mod->trace_events;
1291    end = mod->trace_events + mod->num_trace_events;
1292
1293    if (start == end)
1294        return;
1295
1296    file_ops = trace_create_file_ops(mod);
1297    if (!file_ops)
1298        return;
1299
1300    for_each_event(call, start, end) {
1301        __trace_add_event_call(*call, mod,
1302                       &file_ops->id, &file_ops->enable,
1303                       &file_ops->filter, &file_ops->format);
1304    }
1305}
1306
1307static void trace_module_remove_events(struct module *mod)
1308{
1309    struct ftrace_module_file_ops *file_ops;
1310    struct ftrace_event_call *call, *p;
1311    bool found = false;
1312
1313    down_write(&trace_event_mutex);
1314    list_for_each_entry_safe(call, p, &ftrace_events, list) {
1315        if (call->mod == mod) {
1316            found = true;
1317            __trace_remove_event_call(call);
1318        }
1319    }
1320
1321    /* Now free the file_operations */
1322    list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1323        if (file_ops->mod == mod)
1324            break;
1325    }
1326    if (&file_ops->list != &ftrace_module_file_list) {
1327        list_del(&file_ops->list);
1328        kfree(file_ops);
1329    }
1330
1331    /*
1332     * It is safest to reset the ring buffer if the module being unloaded
1333     * registered any events.
1334     */
1335    if (found)
1336        tracing_reset_current_online_cpus();
1337    up_write(&trace_event_mutex);
1338}
1339
1340static int trace_module_notify(struct notifier_block *self,
1341                   unsigned long val, void *data)
1342{
1343    struct module *mod = data;
1344
1345    mutex_lock(&event_mutex);
1346    switch (val) {
1347    case MODULE_STATE_COMING:
1348        trace_module_add_events(mod);
1349        break;
1350    case MODULE_STATE_GOING:
1351        trace_module_remove_events(mod);
1352        break;
1353    }
1354    mutex_unlock(&event_mutex);
1355
1356    return 0;
1357}
1358#else
1359static int trace_module_notify(struct notifier_block *self,
1360                   unsigned long val, void *data)
1361{
1362    return 0;
1363}
1364#endif /* CONFIG_MODULES */
1365
1366static struct notifier_block trace_module_nb = {
1367    .notifier_call = trace_module_notify,
1368    .priority = 0,
1369};
1370
1371extern struct ftrace_event_call *__start_ftrace_events[];
1372extern struct ftrace_event_call *__stop_ftrace_events[];
1373
1374static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1375
1376static __init int setup_trace_event(char *str)
1377{
1378    strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1379    ring_buffer_expanded = 1;
1380    tracing_selftest_disabled = 1;
1381
1382    return 1;
1383}
1384__setup("trace_event=", setup_trace_event);
1385
1386static __init int event_trace_init(void)
1387{
1388    struct ftrace_event_call **call;
1389    struct dentry *d_tracer;
1390    struct dentry *entry;
1391    struct dentry *d_events;
1392    int ret;
1393    char *buf = bootup_event_buf;
1394    char *token;
1395
1396    d_tracer = tracing_init_dentry();
1397    if (!d_tracer)
1398        return 0;
1399
1400    entry = debugfs_create_file("available_events", 0444, d_tracer,
1401                    (void *)&show_event_seq_ops,
1402                    &ftrace_avail_fops);
1403    if (!entry)
1404        pr_warning("Could not create debugfs "
1405               "'available_events' entry\n");
1406
1407    entry = debugfs_create_file("set_event", 0644, d_tracer,
1408                    (void *)&show_set_event_seq_ops,
1409                    &ftrace_set_event_fops);
1410    if (!entry)
1411        pr_warning("Could not create debugfs "
1412               "'set_event' entry\n");
1413
1414    d_events = event_trace_events_dir();
1415    if (!d_events)
1416        return 0;
1417
1418    /* ring buffer internal formats */
1419    trace_create_file("header_page", 0444, d_events,
1420              ring_buffer_print_page_header,
1421              &ftrace_show_header_fops);
1422
1423    trace_create_file("header_event", 0444, d_events,
1424              ring_buffer_print_entry_header,
1425              &ftrace_show_header_fops);
1426
1427    trace_create_file("enable", 0644, d_events,
1428              NULL, &ftrace_system_enable_fops);
1429
1430    if (trace_define_common_fields())
1431        pr_warning("tracing: Failed to allocate common fields");
1432
1433    for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
1434        __trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
1435                       &ftrace_enable_fops,
1436                       &ftrace_event_filter_fops,
1437                       &ftrace_event_format_fops);
1438    }
1439
1440    while (true) {
1441        token = strsep(&buf, ",");
1442
1443        if (!token)
1444            break;
1445        if (!*token)
1446            continue;
1447
1448        ret = ftrace_set_clr_event(token, 1);
1449        if (ret)
1450            pr_warning("Failed to enable trace event: %s\n", token);
1451    }
1452
1453    ret = register_module_notifier(&trace_module_nb);
1454    if (ret)
1455        pr_warning("Failed to register trace events module notifier\n");
1456
1457    return 0;
1458}
1459fs_initcall(event_trace_init);
1460
1461#ifdef CONFIG_FTRACE_STARTUP_TEST
1462
1463static DEFINE_SPINLOCK(test_spinlock);
1464static DEFINE_SPINLOCK(test_spinlock_irq);
1465static DEFINE_MUTEX(test_mutex);
1466
1467static __init void test_work(struct work_struct *dummy)
1468{
1469    spin_lock(&test_spinlock);
1470    spin_lock_irq(&test_spinlock_irq);
1471    udelay(1);
1472    spin_unlock_irq(&test_spinlock_irq);
1473    spin_unlock(&test_spinlock);
1474
1475    mutex_lock(&test_mutex);
1476    msleep(1);
1477    mutex_unlock(&test_mutex);
1478}
1479
1480static __init int event_test_thread(void *unused)
1481{
1482    void *test_malloc;
1483
1484    test_malloc = kmalloc(1234, GFP_KERNEL);
1485    if (!test_malloc)
1486        pr_info("failed to kmalloc\n");
1487
1488    schedule_on_each_cpu(test_work);
1489
1490    kfree(test_malloc);
1491
1492    set_current_state(TASK_INTERRUPTIBLE);
1493    while (!kthread_should_stop())
1494        schedule();
1495
1496    return 0;
1497}
1498
1499/*
1500 * Do various things that may trigger events.
1501 */
1502static __init void event_test_stuff(void)
1503{
1504    struct task_struct *test_thread;
1505
1506    test_thread = kthread_run(event_test_thread, NULL, "test-events");
1507    msleep(1);
1508    kthread_stop(test_thread);
1509}
1510
1511/*
1512 * For every trace event defined, we will test each trace point separately,
1513 * and then by groups, and finally all trace points.
1514 */
1515static __init void event_trace_self_tests(void)
1516{
1517    struct ftrace_event_call *call;
1518    struct event_subsystem *system;
1519    int ret;
1520
1521    pr_info("Running tests on trace events:\n");
1522
1523    list_for_each_entry(call, &ftrace_events, list) {
1524
1525        /* Only test those that have a probe */
1526        if (!call->class || !call->class->probe)
1527            continue;
1528
1529/*
1530 * Testing syscall events here is pretty useless, but
1531 * we still do it if configured. But this is time consuming.
1532 * What we really need is a user thread to perform the
1533 * syscalls as we test.
1534 */
1535#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1536        if (call->class->system &&
1537            strcmp(call->class->system, "syscalls") == 0)
1538            continue;
1539#endif
1540
1541        pr_info("Testing event %s: ", call->name);
1542
1543        /*
1544         * If an event is already enabled, someone is using
1545         * it and the self test should not be on.
1546         */
1547        if (call->flags & TRACE_EVENT_FL_ENABLED) {
1548            pr_warning("Enabled event during self test!\n");
1549            WARN_ON_ONCE(1);
1550            continue;
1551        }
1552
1553        ftrace_event_enable_disable(call, 1);
1554        event_test_stuff();
1555        ftrace_event_enable_disable(call, 0);
1556
1557        pr_cont("OK\n");
1558    }
1559
1560    /* Now test at the sub system level */
1561
1562    pr_info("Running tests on trace event systems:\n");
1563
1564    list_for_each_entry(system, &event_subsystems, list) {
1565
1566        /* the ftrace system is special, skip it */
1567        if (strcmp(system->name, "ftrace") == 0)
1568            continue;
1569
1570        pr_info("Testing event system %s: ", system->name);
1571
1572        ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1573        if (WARN_ON_ONCE(ret)) {
1574            pr_warning("error enabling system %s\n",
1575                   system->name);
1576            continue;
1577        }
1578
1579        event_test_stuff();
1580
1581        ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1582        if (WARN_ON_ONCE(ret))
1583            pr_warning("error disabling system %s\n",
1584                   system->name);
1585
1586        pr_cont("OK\n");
1587    }
1588
1589    /* Test with all events enabled */
1590
1591    pr_info("Running tests on all trace events:\n");
1592    pr_info("Testing all events: ");
1593
1594    ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1595    if (WARN_ON_ONCE(ret)) {
1596        pr_warning("error enabling all events\n");
1597        return;
1598    }
1599
1600    event_test_stuff();
1601
1602    /* reset sysname */
1603    ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1604    if (WARN_ON_ONCE(ret)) {
1605        pr_warning("error disabling all events\n");
1606        return;
1607    }
1608
1609    pr_cont("OK\n");
1610}
1611
1612#ifdef CONFIG_FUNCTION_TRACER
1613
1614static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1615
1616static void
1617function_test_events_call(unsigned long ip, unsigned long parent_ip)
1618{
1619    struct ring_buffer_event *event;
1620    struct ring_buffer *buffer;
1621    struct ftrace_entry *entry;
1622    unsigned long flags;
1623    long disabled;
1624    int cpu;
1625    int pc;
1626
1627    pc = preempt_count();
1628    preempt_disable_notrace();
1629    cpu = raw_smp_processor_id();
1630    disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1631
1632    if (disabled != 1)
1633        goto out;
1634
1635    local_save_flags(flags);
1636
1637    event = trace_current_buffer_lock_reserve(&buffer,
1638                          TRACE_FN, sizeof(*entry),
1639                          flags, pc);
1640    if (!event)
1641        goto out;
1642    entry = ring_buffer_event_data(event);
1643    entry->ip = ip;
1644    entry->parent_ip = parent_ip;
1645
1646    trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1647
1648 out:
1649    atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1650    preempt_enable_notrace();
1651}
1652
1653static struct ftrace_ops trace_ops __initdata =
1654{
1655    .func = function_test_events_call,
1656};
1657
1658static __init void event_trace_self_test_with_function(void)
1659{
1660    int ret;
1661    ret = register_ftrace_function(&trace_ops);
1662    if (WARN_ON(ret < 0)) {
1663        pr_info("Failed to enable function tracer for event tests\n");
1664        return;
1665    }
1666    pr_info("Running tests again, along with the function tracer\n");
1667    event_trace_self_tests();
1668    unregister_ftrace_function(&trace_ops);
1669}
1670#else
1671static __init void event_trace_self_test_with_function(void)
1672{
1673}
1674#endif
1675
1676static __init int event_trace_self_tests_init(void)
1677{
1678    if (!tracing_selftest_disabled) {
1679        event_trace_self_tests();
1680        event_trace_self_test_with_function();
1681    }
1682
1683    return 0;
1684}
1685
1686late_initcall(event_trace_self_tests_init);
1687
1688#endif
1689

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