4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
6 * - Added format output of fields of the trace point.
7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
11 #include <linux/debugfs.h>
12 #include <linux/uaccess.h>
13 #include <linux/module.h>
14 #include <linux/ctype.h>
16 #include "trace_output.h"
18 #define TRACE_SYSTEM "TRACE_SYSTEM"
20 static DEFINE_MUTEX(event_mutex);
22 LIST_HEAD(ftrace_events);
24 int trace_define_field(struct ftrace_event_call *call, char *type,
25 char *name, int offset, int size)
27 struct ftrace_event_field *field;
29 field = kzalloc(sizeof(*field), GFP_KERNEL);
33 field->name = kstrdup(name, GFP_KERNEL);
37 field->type = kstrdup(type, GFP_KERNEL);
41 field->offset = offset;
43 list_add(&field->link, &call->fields);
56 EXPORT_SYMBOL_GPL(trace_define_field);
58 static void ftrace_clear_events(void)
60 struct ftrace_event_call *call;
62 list_for_each_entry(call, &ftrace_events, list) {
71 static void ftrace_event_enable_disable(struct ftrace_event_call *call,
91 static int ftrace_set_clr_event(char *buf, int set)
93 struct ftrace_event_call *call;
94 char *event = NULL, *sub = NULL, *match;
98 * The buf format can be <subsystem>:<event-name>
99 * *:<event-name> means any event by that name.
100 * :<event-name> is the same.
102 * <subsystem>:* means all events in that subsystem
103 * <subsystem>: means the same.
105 * <name> (no ':') means all events in a subsystem with
106 * the name <name> or any event that matches <name>
109 match = strsep(&buf, ":");
115 if (!strlen(sub) || strcmp(sub, "*") == 0)
117 if (!strlen(event) || strcmp(event, "*") == 0)
121 mutex_lock(&event_mutex);
122 list_for_each_entry(call, &ftrace_events, list) {
124 if (!call->name || !call->regfunc)
128 strcmp(match, call->name) != 0 &&
129 strcmp(match, call->system) != 0)
132 if (sub && strcmp(sub, call->system) != 0)
135 if (event && strcmp(event, call->name) != 0)
138 ftrace_event_enable_disable(call, set);
142 mutex_unlock(&event_mutex);
147 /* 128 should be much more than enough */
148 #define EVENT_BUF_SIZE 127
151 ftrace_event_write(struct file *file, const char __user *ubuf,
152 size_t cnt, loff_t *ppos)
163 ret = tracing_update_buffers();
167 ret = get_user(ch, ubuf++);
173 /* skip white space */
174 while (cnt && isspace(ch)) {
175 ret = get_user(ch, ubuf++);
182 /* Only white space found? */
189 buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
193 if (cnt > EVENT_BUF_SIZE)
194 cnt = EVENT_BUF_SIZE;
197 while (cnt && !isspace(ch)) {
203 ret = get_user(ch, ubuf++);
213 ret = ftrace_set_clr_event(buf, set);
226 t_next(struct seq_file *m, void *v, loff_t *pos)
228 struct list_head *list = m->private;
229 struct ftrace_event_call *call;
234 if (list == &ftrace_events)
237 call = list_entry(list, struct ftrace_event_call, list);
240 * The ftrace subsystem is for showing formats only.
241 * They can not be enabled or disabled via the event files.
249 m->private = list->next;
254 static void *t_start(struct seq_file *m, loff_t *pos)
256 return t_next(m, NULL, pos);
260 s_next(struct seq_file *m, void *v, loff_t *pos)
262 struct list_head *list = m->private;
263 struct ftrace_event_call *call;
268 if (list == &ftrace_events)
271 call = list_entry(list, struct ftrace_event_call, list);
273 if (!call->enabled) {
278 m->private = list->next;
283 static void *s_start(struct seq_file *m, loff_t *pos)
285 return s_next(m, NULL, pos);
288 static int t_show(struct seq_file *m, void *v)
290 struct ftrace_event_call *call = v;
292 if (strcmp(call->system, TRACE_SYSTEM) != 0)
293 seq_printf(m, "%s:", call->system);
294 seq_printf(m, "%s\n", call->name);
299 static void t_stop(struct seq_file *m, void *p)
304 ftrace_event_seq_open(struct inode *inode, struct file *file)
307 const struct seq_operations *seq_ops;
309 if ((file->f_mode & FMODE_WRITE) &&
310 !(file->f_flags & O_APPEND))
311 ftrace_clear_events();
313 seq_ops = inode->i_private;
314 ret = seq_open(file, seq_ops);
316 struct seq_file *m = file->private_data;
318 m->private = ftrace_events.next;
324 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
327 struct ftrace_event_call *call = filp->private_data;
335 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
339 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
342 struct ftrace_event_call *call = filp->private_data;
347 if (cnt >= sizeof(buf))
350 if (copy_from_user(&buf, ubuf, cnt))
355 ret = strict_strtoul(buf, 10, &val);
359 ret = tracing_update_buffers();
366 mutex_lock(&event_mutex);
367 ftrace_event_enable_disable(call, val);
368 mutex_unlock(&event_mutex);
381 #define FIELD(type, name) \
382 #type, "common_" #name, offsetof(typeof(field), name), \
385 static int trace_write_header(struct trace_seq *s)
387 struct trace_entry field;
389 /* struct trace_entry */
390 return trace_seq_printf(s,
391 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
392 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
393 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
394 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
395 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
397 FIELD(unsigned char, type),
398 FIELD(unsigned char, flags),
399 FIELD(unsigned char, preempt_count),
405 event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
408 struct ftrace_event_call *call = filp->private_data;
416 s = kmalloc(sizeof(*s), GFP_KERNEL);
422 /* If any of the first writes fail, so will the show_format. */
424 trace_seq_printf(s, "name: %s\n", call->name);
425 trace_seq_printf(s, "ID: %d\n", call->id);
426 trace_seq_printf(s, "format:\n");
427 trace_write_header(s);
429 r = call->show_format(s);
432 * ug! The format output is bigger than a PAGE!!
434 buf = "FORMAT TOO BIG\n";
435 r = simple_read_from_buffer(ubuf, cnt, ppos,
440 r = simple_read_from_buffer(ubuf, cnt, ppos,
448 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
450 struct ftrace_event_call *call = filp->private_data;
457 s = kmalloc(sizeof(*s), GFP_KERNEL);
462 trace_seq_printf(s, "%d\n", call->id);
464 r = simple_read_from_buffer(ubuf, cnt, ppos,
471 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
474 struct ftrace_event_call *call = filp->private_data;
481 s = kmalloc(sizeof(*s), GFP_KERNEL);
487 filter_print_preds(call->preds, call->n_preds, s);
488 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
496 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
499 struct ftrace_event_call *call = filp->private_data;
500 char buf[64], *pbuf = buf;
501 struct filter_pred *pred;
504 if (cnt >= sizeof(buf))
507 if (copy_from_user(&buf, ubuf, cnt))
511 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
515 err = filter_parse(&pbuf, pred);
517 filter_free_pred(pred);
522 filter_disable_preds(call);
523 filter_free_pred(pred);
527 err = filter_add_pred(call, pred);
529 filter_free_pred(pred);
533 filter_free_pred(pred);
541 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
544 struct event_subsystem *system = filp->private_data;
551 s = kmalloc(sizeof(*s), GFP_KERNEL);
557 filter_print_preds(system->preds, system->n_preds, s);
558 r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
566 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
569 struct event_subsystem *system = filp->private_data;
570 char buf[64], *pbuf = buf;
571 struct filter_pred *pred;
574 if (cnt >= sizeof(buf))
577 if (copy_from_user(&buf, ubuf, cnt))
581 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
585 err = filter_parse(&pbuf, pred);
587 filter_free_pred(pred);
592 filter_free_subsystem_preds(system);
593 filter_free_pred(pred);
597 err = filter_add_subsystem_pred(system, pred);
599 filter_free_subsystem_preds(system);
600 filter_free_pred(pred);
609 static const struct seq_operations show_event_seq_ops = {
616 static const struct seq_operations show_set_event_seq_ops = {
623 static const struct file_operations ftrace_avail_fops = {
624 .open = ftrace_event_seq_open,
627 .release = seq_release,
630 static const struct file_operations ftrace_set_event_fops = {
631 .open = ftrace_event_seq_open,
633 .write = ftrace_event_write,
635 .release = seq_release,
638 static const struct file_operations ftrace_enable_fops = {
639 .open = tracing_open_generic,
640 .read = event_enable_read,
641 .write = event_enable_write,
644 static const struct file_operations ftrace_event_format_fops = {
645 .open = tracing_open_generic,
646 .read = event_format_read,
649 static const struct file_operations ftrace_event_id_fops = {
650 .open = tracing_open_generic,
651 .read = event_id_read,
654 static const struct file_operations ftrace_event_filter_fops = {
655 .open = tracing_open_generic,
656 .read = event_filter_read,
657 .write = event_filter_write,
660 static const struct file_operations ftrace_subsystem_filter_fops = {
661 .open = tracing_open_generic,
662 .read = subsystem_filter_read,
663 .write = subsystem_filter_write,
666 static struct dentry *event_trace_events_dir(void)
668 static struct dentry *d_tracer;
669 static struct dentry *d_events;
674 d_tracer = tracing_init_dentry();
678 d_events = debugfs_create_dir("events", d_tracer);
680 pr_warning("Could not create debugfs "
681 "'events' directory\n");
686 static LIST_HEAD(event_subsystems);
688 static struct dentry *
689 event_subsystem_dir(const char *name, struct dentry *d_events)
691 struct event_subsystem *system;
692 struct dentry *entry;
694 /* First see if we did not already create this dir */
695 list_for_each_entry(system, &event_subsystems, list) {
696 if (strcmp(system->name, name) == 0)
697 return system->entry;
700 /* need to create new entry */
701 system = kmalloc(sizeof(*system), GFP_KERNEL);
703 pr_warning("No memory to create event subsystem %s\n",
708 system->entry = debugfs_create_dir(name, d_events);
709 if (!system->entry) {
710 pr_warning("Could not create event subsystem %s\n",
716 system->name = kstrdup(name, GFP_KERNEL);
718 debugfs_remove(system->entry);
723 list_add(&system->list, &event_subsystems);
725 system->preds = NULL;
728 entry = debugfs_create_file("filter", 0644, system->entry, system,
729 &ftrace_subsystem_filter_fops);
731 pr_warning("Could not create debugfs "
732 "'%s/filter' entry\n", name);
734 return system->entry;
738 event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
740 struct dentry *entry;
744 * If the trace point header did not define TRACE_SYSTEM
745 * then the system would be called "TRACE_SYSTEM".
747 if (strcmp(call->system, TRACE_SYSTEM) != 0)
748 d_events = event_subsystem_dir(call->system, d_events);
750 if (call->raw_init) {
751 ret = call->raw_init();
753 pr_warning("Could not initialize trace point"
754 " events/%s\n", call->name);
759 call->dir = debugfs_create_dir(call->name, d_events);
761 pr_warning("Could not create debugfs "
762 "'%s' directory\n", call->name);
767 entry = trace_create_file("enable", 0644, call->dir, call,
768 &ftrace_enable_fops);
771 entry = trace_create_file("id", 0444, call->dir, call,
772 &ftrace_event_id_fops);
774 if (call->define_fields) {
775 ret = call->define_fields();
777 pr_warning("Could not initialize trace point"
778 " events/%s\n", call->name);
781 entry = trace_create_file("filter", 0644, call->dir, call,
782 &ftrace_event_filter_fops);
785 /* A trace may not want to export its format */
786 if (!call->show_format)
789 entry = trace_create_file("format", 0444, call->dir, call,
790 &ftrace_event_format_fops);
795 #define for_each_event(event, start, end) \
796 for (event = start; \
797 (unsigned long)event < (unsigned long)end; \
800 static void trace_module_add_events(struct module *mod)
802 struct ftrace_event_call *call, *start, *end;
803 struct dentry *d_events;
805 start = mod->trace_events;
806 end = mod->trace_events + mod->num_trace_events;
811 d_events = event_trace_events_dir();
815 for_each_event(call, start, end) {
816 /* The linker may leave blanks */
820 list_add(&call->list, &ftrace_events);
821 event_create_dir(call, d_events);
825 static void trace_module_remove_events(struct module *mod)
827 struct ftrace_event_call *call, *p;
829 list_for_each_entry_safe(call, p, &ftrace_events, list) {
830 if (call->mod == mod) {
836 unregister_ftrace_event(call->event);
837 debugfs_remove_recursive(call->dir);
838 list_del(&call->list);
843 int trace_module_notify(struct notifier_block *self,
844 unsigned long val, void *data)
846 struct module *mod = data;
848 mutex_lock(&event_mutex);
850 case MODULE_STATE_COMING:
851 trace_module_add_events(mod);
853 case MODULE_STATE_GOING:
854 trace_module_remove_events(mod);
857 mutex_unlock(&event_mutex);
862 struct notifier_block trace_module_nb = {
863 .notifier_call = trace_module_notify,
867 extern struct ftrace_event_call __start_ftrace_events[];
868 extern struct ftrace_event_call __stop_ftrace_events[];
870 static __init int event_trace_init(void)
872 struct ftrace_event_call *call;
873 struct dentry *d_tracer;
874 struct dentry *entry;
875 struct dentry *d_events;
878 d_tracer = tracing_init_dentry();
882 entry = debugfs_create_file("available_events", 0444, d_tracer,
883 (void *)&show_event_seq_ops,
886 pr_warning("Could not create debugfs "
887 "'available_events' entry\n");
889 entry = debugfs_create_file("set_event", 0644, d_tracer,
890 (void *)&show_set_event_seq_ops,
891 &ftrace_set_event_fops);
893 pr_warning("Could not create debugfs "
894 "'set_event' entry\n");
896 d_events = event_trace_events_dir();
900 for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
901 /* The linker may leave blanks */
904 list_add(&call->list, &ftrace_events);
905 event_create_dir(call, d_events);
908 ret = register_module_notifier(&trace_module_nb);
910 pr_warning("Failed to register trace events module notifier\n");
914 fs_initcall(event_trace_init);