1
linux/kernel/trace/trace_events.c
Xiao Guangrong dc82ec98a4 tracing/filter: Remove empty subsystem and its directory
Remove empty subsystem and its directory when module unload.

Before patch:
 # rmmod trace-events-sample.ko
 # ls sample
 enable  filter

After patch:
 # rmmod trace-events-sample.ko
 # ls sample
 ls: cannot access sample: No such file or directory

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A55A8BE.9010707@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-10 11:55:28 +02:00

1465 lines
30 KiB
C

/*
* event tracer
*
* Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* - Added format output of fields of the trace point.
* This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
*
*/
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <asm/setup.h>
#include "trace_output.h"
#define TRACE_SYSTEM "TRACE_SYSTEM"
DEFINE_MUTEX(event_mutex);
LIST_HEAD(ftrace_events);
int trace_define_field(struct ftrace_event_call *call, char *type,
char *name, int offset, int size, int is_signed)
{
struct ftrace_event_field *field;
field = kzalloc(sizeof(*field), GFP_KERNEL);
if (!field)
goto err;
field->name = kstrdup(name, GFP_KERNEL);
if (!field->name)
goto err;
field->type = kstrdup(type, GFP_KERNEL);
if (!field->type)
goto err;
field->offset = offset;
field->size = size;
field->is_signed = is_signed;
list_add(&field->link, &call->fields);
return 0;
err:
if (field) {
kfree(field->name);
kfree(field->type);
}
kfree(field);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(trace_define_field);
#ifdef CONFIG_MODULES
static void trace_destroy_fields(struct ftrace_event_call *call)
{
struct ftrace_event_field *field, *next;
list_for_each_entry_safe(field, next, &call->fields, link) {
list_del(&field->link);
kfree(field->type);
kfree(field->name);
kfree(field);
}
}
#endif /* CONFIG_MODULES */
static void ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
switch (enable) {
case 0:
if (call->enabled) {
call->enabled = 0;
tracing_stop_cmdline_record();
call->unregfunc();
}
break;
case 1:
if (!call->enabled) {
call->enabled = 1;
tracing_start_cmdline_record();
call->regfunc();
}
break;
}
}
static void ftrace_clear_events(void)
{
struct ftrace_event_call *call;
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
ftrace_event_enable_disable(call, 0);
}
mutex_unlock(&event_mutex);
}
/*
* __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
*/
static int __ftrace_set_clr_event(const char *match, const char *sub,
const char *event, int set)
{
struct ftrace_event_call *call;
int ret = -EINVAL;
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->name || !call->regfunc)
continue;
if (match &&
strcmp(match, call->name) != 0 &&
strcmp(match, call->system) != 0)
continue;
if (sub && strcmp(sub, call->system) != 0)
continue;
if (event && strcmp(event, call->name) != 0)
continue;
ftrace_event_enable_disable(call, set);
ret = 0;
}
mutex_unlock(&event_mutex);
return ret;
}
static int ftrace_set_clr_event(char *buf, int set)
{
char *event = NULL, *sub = NULL, *match;
/*
* The buf format can be <subsystem>:<event-name>
* *:<event-name> means any event by that name.
* :<event-name> is the same.
*
* <subsystem>:* means all events in that subsystem
* <subsystem>: means the same.
*
* <name> (no ':') means all events in a subsystem with
* the name <name> or any event that matches <name>
*/
match = strsep(&buf, ":");
if (buf) {
sub = match;
event = buf;
match = NULL;
if (!strlen(sub) || strcmp(sub, "*") == 0)
sub = NULL;
if (!strlen(event) || strcmp(event, "*") == 0)
event = NULL;
}
return __ftrace_set_clr_event(match, sub, event, set);
}
/**
* trace_set_clr_event - enable or disable an event
* @system: system name to match (NULL for any system)
* @event: event name to match (NULL for all events, within system)
* @set: 1 to enable, 0 to disable
*
* This is a way for other parts of the kernel to enable or disable
* event recording.
*
* Returns 0 on success, -EINVAL if the parameters do not match any
* registered events.
*/
int trace_set_clr_event(const char *system, const char *event, int set)
{
return __ftrace_set_clr_event(NULL, system, event, set);
}
/* 128 should be much more than enough */
#define EVENT_BUF_SIZE 127
static ssize_t
ftrace_event_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
size_t read = 0;
int i, set = 1;
ssize_t ret;
char *buf;
char ch;
if (!cnt || cnt < 0)
return 0;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
ret = get_user(ch, ubuf++);
if (ret)
return ret;
read++;
cnt--;
/* skip white space */
while (cnt && isspace(ch)) {
ret = get_user(ch, ubuf++);
if (ret)
return ret;
read++;
cnt--;
}
/* Only white space found? */
if (isspace(ch)) {
file->f_pos += read;
ret = read;
return ret;
}
buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (cnt > EVENT_BUF_SIZE)
cnt = EVENT_BUF_SIZE;
i = 0;
while (cnt && !isspace(ch)) {
if (!i && ch == '!')
set = 0;
else
buf[i++] = ch;
ret = get_user(ch, ubuf++);
if (ret)
goto out_free;
read++;
cnt--;
}
buf[i] = 0;
file->f_pos += read;
ret = ftrace_set_clr_event(buf, set);
if (ret)
goto out_free;
ret = read;
out_free:
kfree(buf);
return ret;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct list_head *list = m->private;
struct ftrace_event_call *call;
(*pos)++;
for (;;) {
if (list == &ftrace_events)
return NULL;
call = list_entry(list, struct ftrace_event_call, list);
/*
* The ftrace subsystem is for showing formats only.
* They can not be enabled or disabled via the event files.
*/
if (call->regfunc)
break;
list = list->next;
}
m->private = list->next;
return call;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_event_call *call = NULL;
loff_t l;
mutex_lock(&event_mutex);
m->private = ftrace_events.next;
for (l = 0; l <= *pos; ) {
call = t_next(m, NULL, &l);
if (!call)
break;
}
return call;
}
static void *
s_next(struct seq_file *m, void *v, loff_t *pos)
{
struct list_head *list = m->private;
struct ftrace_event_call *call;
(*pos)++;
retry:
if (list == &ftrace_events)
return NULL;
call = list_entry(list, struct ftrace_event_call, list);
if (!call->enabled) {
list = list->next;
goto retry;
}
m->private = list->next;
return call;
}
static void *s_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_event_call *call = NULL;
loff_t l;
mutex_lock(&event_mutex);
m->private = ftrace_events.next;
for (l = 0; l <= *pos; ) {
call = s_next(m, NULL, &l);
if (!call)
break;
}
return call;
}
static int t_show(struct seq_file *m, void *v)
{
struct ftrace_event_call *call = v;
if (strcmp(call->system, TRACE_SYSTEM) != 0)
seq_printf(m, "%s:", call->system);
seq_printf(m, "%s\n", call->name);
return 0;
}
static void t_stop(struct seq_file *m, void *p)
{
mutex_unlock(&event_mutex);
}
static int
ftrace_event_seq_open(struct inode *inode, struct file *file)
{
const struct seq_operations *seq_ops;
if ((file->f_mode & FMODE_WRITE) &&
!(file->f_flags & O_APPEND))
ftrace_clear_events();
seq_ops = inode->i_private;
return seq_open(file, seq_ops);
}
static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char *buf;
if (call->enabled)
buf = "1\n";
else
buf = "0\n";
return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
}
static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char buf[64];
unsigned long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
return ret;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
switch (val) {
case 0:
case 1:
mutex_lock(&event_mutex);
ftrace_event_enable_disable(call, val);
mutex_unlock(&event_mutex);
break;
default:
return -EINVAL;
}
*ppos += cnt;
return cnt;
}
static ssize_t
system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
const char set_to_char[4] = { '?', '0', '1', 'X' };
const char *system = filp->private_data;
struct ftrace_event_call *call;
char buf[2];
int set = 0;
int ret;
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->name || !call->regfunc)
continue;
if (system && strcmp(call->system, system) != 0)
continue;
/*
* We need to find out if all the events are set
* or if all events or cleared, or if we have
* a mixture.
*/
set |= (1 << !!call->enabled);
/*
* If we have a mixture, no need to look further.
*/
if (set == 3)
break;
}
mutex_unlock(&event_mutex);
buf[0] = set_to_char[set];
buf[1] = '\n';
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
return ret;
}
static ssize_t
system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
const char *system = filp->private_data;
unsigned long val;
char buf[64];
ssize_t ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
return ret;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
if (val != 0 && val != 1)
return -EINVAL;
ret = __ftrace_set_clr_event(NULL, system, NULL, val);
if (ret)
goto out;
ret = cnt;
out:
*ppos += cnt;
return ret;
}
extern char *__bad_type_size(void);
#undef FIELD
#define FIELD(type, name) \
sizeof(type) != sizeof(field.name) ? __bad_type_size() : \
#type, "common_" #name, offsetof(typeof(field), name), \
sizeof(field.name)
static int trace_write_header(struct trace_seq *s)
{
struct trace_entry field;
/* struct trace_entry */
return trace_seq_printf(s,
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
"\n",
FIELD(unsigned short, type),
FIELD(unsigned char, flags),
FIELD(unsigned char, preempt_count),
FIELD(int, pid),
FIELD(int, tgid));
}
static ssize_t
event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
struct trace_seq *s;
char *buf;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
/* If any of the first writes fail, so will the show_format. */
trace_seq_printf(s, "name: %s\n", call->name);
trace_seq_printf(s, "ID: %d\n", call->id);
trace_seq_printf(s, "format:\n");
trace_write_header(s);
r = call->show_format(s);
if (!r) {
/*
* ug! The format output is bigger than a PAGE!!
*/
buf = "FORMAT TOO BIG\n";
r = simple_read_from_buffer(ubuf, cnt, ppos,
buf, strlen(buf));
goto out;
}
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, s->len);
out:
kfree(s);
return r;
}
static ssize_t
event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
trace_seq_printf(s, "%d\n", call->id);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, s->len);
kfree(s);
return r;
}
static ssize_t
event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
print_event_filter(call, s);
r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
kfree(s);
return r;
}
static ssize_t
event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct ftrace_event_call *call = filp->private_data;
char *buf;
int err;
if (cnt >= PAGE_SIZE)
return -EINVAL;
buf = (char *)__get_free_page(GFP_TEMPORARY);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, ubuf, cnt)) {
free_page((unsigned long) buf);
return -EFAULT;
}
buf[cnt] = '\0';
err = apply_event_filter(call, buf);
free_page((unsigned long) buf);
if (err < 0)
return err;
*ppos += cnt;
return cnt;
}
static ssize_t
subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct event_subsystem *system = filp->private_data;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
print_subsystem_event_filter(system, s);
r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
kfree(s);
return r;
}
static ssize_t
subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct event_subsystem *system = filp->private_data;
char *buf;
int err;
if (cnt >= PAGE_SIZE)
return -EINVAL;
buf = (char *)__get_free_page(GFP_TEMPORARY);
if (!buf)
return -ENOMEM;
if (copy_from_user(buf, ubuf, cnt)) {
free_page((unsigned long) buf);
return -EFAULT;
}
buf[cnt] = '\0';
err = apply_subsystem_event_filter(system, buf);
free_page((unsigned long) buf);
if (err < 0)
return err;
*ppos += cnt;
return cnt;
}
static ssize_t
show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
int (*func)(struct trace_seq *s) = filp->private_data;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
func(s);
r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
kfree(s);
return r;
}
static const struct seq_operations show_event_seq_ops = {
.start = t_start,
.next = t_next,
.show = t_show,
.stop = t_stop,
};
static const struct seq_operations show_set_event_seq_ops = {
.start = s_start,
.next = s_next,
.show = t_show,
.stop = t_stop,
};
static const struct file_operations ftrace_avail_fops = {
.open = ftrace_event_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations ftrace_set_event_fops = {
.open = ftrace_event_seq_open,
.read = seq_read,
.write = ftrace_event_write,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations ftrace_enable_fops = {
.open = tracing_open_generic,
.read = event_enable_read,
.write = event_enable_write,
};
static const struct file_operations ftrace_event_format_fops = {
.open = tracing_open_generic,
.read = event_format_read,
};
static const struct file_operations ftrace_event_id_fops = {
.open = tracing_open_generic,
.read = event_id_read,
};
static const struct file_operations ftrace_event_filter_fops = {
.open = tracing_open_generic,
.read = event_filter_read,
.write = event_filter_write,
};
static const struct file_operations ftrace_subsystem_filter_fops = {
.open = tracing_open_generic,
.read = subsystem_filter_read,
.write = subsystem_filter_write,
};
static const struct file_operations ftrace_system_enable_fops = {
.open = tracing_open_generic,
.read = system_enable_read,
.write = system_enable_write,
};
static const struct file_operations ftrace_show_header_fops = {
.open = tracing_open_generic,
.read = show_header,
};
static struct dentry *event_trace_events_dir(void)
{
static struct dentry *d_tracer;
static struct dentry *d_events;
if (d_events)
return d_events;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return NULL;
d_events = debugfs_create_dir("events", d_tracer);
if (!d_events)
pr_warning("Could not create debugfs "
"'events' directory\n");
return d_events;
}
static LIST_HEAD(event_subsystems);
static struct dentry *
event_subsystem_dir(const char *name, struct dentry *d_events)
{
struct event_subsystem *system;
struct dentry *entry;
/* First see if we did not already create this dir */
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0) {
system->nr_events++;
return system->entry;
}
}
/* need to create new entry */
system = kmalloc(sizeof(*system), GFP_KERNEL);
if (!system) {
pr_warning("No memory to create event subsystem %s\n",
name);
return d_events;
}
system->entry = debugfs_create_dir(name, d_events);
if (!system->entry) {
pr_warning("Could not create event subsystem %s\n",
name);
kfree(system);
return d_events;
}
system->nr_events = 1;
system->name = kstrdup(name, GFP_KERNEL);
if (!system->name) {
debugfs_remove(system->entry);
kfree(system);
return d_events;
}
list_add(&system->list, &event_subsystems);
system->filter = NULL;
system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
if (!system->filter) {
pr_warning("Could not allocate filter for subsystem "
"'%s'\n", name);
return system->entry;
}
entry = debugfs_create_file("filter", 0644, system->entry, system,
&ftrace_subsystem_filter_fops);
if (!entry) {
kfree(system->filter);
system->filter = NULL;
pr_warning("Could not create debugfs "
"'%s/filter' entry\n", name);
}
entry = trace_create_file("enable", 0644, system->entry,
(void *)system->name,
&ftrace_system_enable_fops);
return system->entry;
}
static void remove_subsystem_dir(const char *name)
{
struct event_subsystem *system;
if (strcmp(name, TRACE_SYSTEM) == 0)
return;
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0) {
if (!--system->nr_events) {
struct event_filter *filter = system->filter;
debugfs_remove_recursive(system->entry);
list_del(&system->list);
if (filter) {
kfree(filter->filter_string);
kfree(filter);
}
kfree(system->name);
kfree(system);
}
break;
}
}
}
static int
event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
const struct file_operations *id,
const struct file_operations *enable,
const struct file_operations *filter,
const struct file_operations *format)
{
struct dentry *entry;
int ret;
/*
* If the trace point header did not define TRACE_SYSTEM
* then the system would be called "TRACE_SYSTEM".
*/
if (strcmp(call->system, TRACE_SYSTEM) != 0)
d_events = event_subsystem_dir(call->system, d_events);
if (call->raw_init) {
ret = call->raw_init();
if (ret < 0) {
pr_warning("Could not initialize trace point"
" events/%s\n", call->name);
return ret;
}
}
call->dir = debugfs_create_dir(call->name, d_events);
if (!call->dir) {
pr_warning("Could not create debugfs "
"'%s' directory\n", call->name);
return -1;
}
if (call->regfunc)
entry = trace_create_file("enable", 0644, call->dir, call,
enable);
if (call->id)
entry = trace_create_file("id", 0444, call->dir, call,
id);
if (call->define_fields) {
ret = call->define_fields();
if (ret < 0) {
pr_warning("Could not initialize trace point"
" events/%s\n", call->name);
return ret;
}
entry = trace_create_file("filter", 0644, call->dir, call,
filter);
}
/* A trace may not want to export its format */
if (!call->show_format)
return 0;
entry = trace_create_file("format", 0444, call->dir, call,
format);
return 0;
}
#define for_each_event(event, start, end) \
for (event = start; \
(unsigned long)event < (unsigned long)end; \
event++)
#ifdef CONFIG_MODULES
static LIST_HEAD(ftrace_module_file_list);
/*
* Modules must own their file_operations to keep up with
* reference counting.
*/
struct ftrace_module_file_ops {
struct list_head list;
struct module *mod;
struct file_operations id;
struct file_operations enable;
struct file_operations format;
struct file_operations filter;
};
static struct ftrace_module_file_ops *
trace_create_file_ops(struct module *mod)
{
struct ftrace_module_file_ops *file_ops;
/*
* This is a bit of a PITA. To allow for correct reference
* counting, modules must "own" their file_operations.
* To do this, we allocate the file operations that will be
* used in the event directory.
*/
file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
if (!file_ops)
return NULL;
file_ops->mod = mod;
file_ops->id = ftrace_event_id_fops;
file_ops->id.owner = mod;
file_ops->enable = ftrace_enable_fops;
file_ops->enable.owner = mod;
file_ops->filter = ftrace_event_filter_fops;
file_ops->filter.owner = mod;
file_ops->format = ftrace_event_format_fops;
file_ops->format.owner = mod;
list_add(&file_ops->list, &ftrace_module_file_list);
return file_ops;
}
static void trace_module_add_events(struct module *mod)
{
struct ftrace_module_file_ops *file_ops = NULL;
struct ftrace_event_call *call, *start, *end;
struct dentry *d_events;
start = mod->trace_events;
end = mod->trace_events + mod->num_trace_events;
if (start == end)
return;
d_events = event_trace_events_dir();
if (!d_events)
return;
for_each_event(call, start, end) {
/* The linker may leave blanks */
if (!call->name)
continue;
/*
* This module has events, create file ops for this module
* if not already done.
*/
if (!file_ops) {
file_ops = trace_create_file_ops(mod);
if (!file_ops)
return;
}
call->mod = mod;
list_add(&call->list, &ftrace_events);
event_create_dir(call, d_events,
&file_ops->id, &file_ops->enable,
&file_ops->filter, &file_ops->format);
}
}
static void trace_module_remove_events(struct module *mod)
{
struct ftrace_module_file_ops *file_ops;
struct ftrace_event_call *call, *p;
bool found = false;
down_write(&trace_event_mutex);
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if (call->mod == mod) {
found = true;
ftrace_event_enable_disable(call, 0);
if (call->event)
__unregister_ftrace_event(call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
trace_destroy_fields(call);
destroy_preds(call);
remove_subsystem_dir(call->system);
}
}
/* Now free the file_operations */
list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
if (file_ops->mod == mod)
break;
}
if (&file_ops->list != &ftrace_module_file_list) {
list_del(&file_ops->list);
kfree(file_ops);
}
/*
* It is safest to reset the ring buffer if the module being unloaded
* registered any events.
*/
if (found)
tracing_reset_current_online_cpus();
up_write(&trace_event_mutex);
}
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
mutex_lock(&event_mutex);
switch (val) {
case MODULE_STATE_COMING:
trace_module_add_events(mod);
break;
case MODULE_STATE_GOING:
trace_module_remove_events(mod);
break;
}
mutex_unlock(&event_mutex);
return 0;
}
#else
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return 0;
}
#endif /* CONFIG_MODULES */
struct notifier_block trace_module_nb = {
.notifier_call = trace_module_notify,
.priority = 0,
};
extern struct ftrace_event_call __start_ftrace_events[];
extern struct ftrace_event_call __stop_ftrace_events[];
static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
static __init int setup_trace_event(char *str)
{
strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
ring_buffer_expanded = 1;
tracing_selftest_disabled = 1;
return 1;
}
__setup("trace_event=", setup_trace_event);
static __init int event_trace_init(void)
{
struct ftrace_event_call *call;
struct dentry *d_tracer;
struct dentry *entry;
struct dentry *d_events;
int ret;
char *buf = bootup_event_buf;
char *token;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return 0;
entry = debugfs_create_file("available_events", 0444, d_tracer,
(void *)&show_event_seq_ops,
&ftrace_avail_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'available_events' entry\n");
entry = debugfs_create_file("set_event", 0644, d_tracer,
(void *)&show_set_event_seq_ops,
&ftrace_set_event_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'set_event' entry\n");
d_events = event_trace_events_dir();
if (!d_events)
return 0;
/* ring buffer internal formats */
trace_create_file("header_page", 0444, d_events,
ring_buffer_print_page_header,
&ftrace_show_header_fops);
trace_create_file("header_event", 0444, d_events,
ring_buffer_print_entry_header,
&ftrace_show_header_fops);
trace_create_file("enable", 0644, d_events,
NULL, &ftrace_system_enable_fops);
for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
/* The linker may leave blanks */
if (!call->name)
continue;
list_add(&call->list, &ftrace_events);
event_create_dir(call, d_events, &ftrace_event_id_fops,
&ftrace_enable_fops, &ftrace_event_filter_fops,
&ftrace_event_format_fops);
}
while (true) {
token = strsep(&buf, ",");
if (!token)
break;
if (!*token)
continue;
ret = ftrace_set_clr_event(token, 1);
if (ret)
pr_warning("Failed to enable trace event: %s\n", token);
}
ret = register_module_notifier(&trace_module_nb);
if (ret)
pr_warning("Failed to register trace events module notifier\n");
return 0;
}
fs_initcall(event_trace_init);
#ifdef CONFIG_FTRACE_STARTUP_TEST
static DEFINE_SPINLOCK(test_spinlock);
static DEFINE_SPINLOCK(test_spinlock_irq);
static DEFINE_MUTEX(test_mutex);
static __init void test_work(struct work_struct *dummy)
{
spin_lock(&test_spinlock);
spin_lock_irq(&test_spinlock_irq);
udelay(1);
spin_unlock_irq(&test_spinlock_irq);
spin_unlock(&test_spinlock);
mutex_lock(&test_mutex);
msleep(1);
mutex_unlock(&test_mutex);
}
static __init int event_test_thread(void *unused)
{
void *test_malloc;
test_malloc = kmalloc(1234, GFP_KERNEL);
if (!test_malloc)
pr_info("failed to kmalloc\n");
schedule_on_each_cpu(test_work);
kfree(test_malloc);
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop())
schedule();
return 0;
}
/*
* Do various things that may trigger events.
*/
static __init void event_test_stuff(void)
{
struct task_struct *test_thread;
test_thread = kthread_run(event_test_thread, NULL, "test-events");
msleep(1);
kthread_stop(test_thread);
}
/*
* For every trace event defined, we will test each trace point separately,
* and then by groups, and finally all trace points.
*/
static __init void event_trace_self_tests(void)
{
struct ftrace_event_call *call;
struct event_subsystem *system;
int ret;
pr_info("Running tests on trace events:\n");
list_for_each_entry(call, &ftrace_events, list) {
/* Only test those that have a regfunc */
if (!call->regfunc)
continue;
pr_info("Testing event %s: ", call->name);
/*
* If an event is already enabled, someone is using
* it and the self test should not be on.
*/
if (call->enabled) {
pr_warning("Enabled event during self test!\n");
WARN_ON_ONCE(1);
continue;
}
ftrace_event_enable_disable(call, 1);
event_test_stuff();
ftrace_event_enable_disable(call, 0);
pr_cont("OK\n");
}
/* Now test at the sub system level */
pr_info("Running tests on trace event systems:\n");
list_for_each_entry(system, &event_subsystems, list) {
/* the ftrace system is special, skip it */
if (strcmp(system->name, "ftrace") == 0)
continue;
pr_info("Testing event system %s: ", system->name);
ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
if (WARN_ON_ONCE(ret)) {
pr_warning("error enabling system %s\n",
system->name);
continue;
}
event_test_stuff();
ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
if (WARN_ON_ONCE(ret))
pr_warning("error disabling system %s\n",
system->name);
pr_cont("OK\n");
}
/* Test with all events enabled */
pr_info("Running tests on all trace events:\n");
pr_info("Testing all events: ");
ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
if (WARN_ON_ONCE(ret)) {
pr_warning("error enabling all events\n");
return;
}
event_test_stuff();
/* reset sysname */
ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
if (WARN_ON_ONCE(ret)) {
pr_warning("error disabling all events\n");
return;
}
pr_cont("OK\n");
}
#ifdef CONFIG_FUNCTION_TRACER
static DEFINE_PER_CPU(atomic_t, test_event_disable);
static void
function_test_events_call(unsigned long ip, unsigned long parent_ip)
{
struct ring_buffer_event *event;
struct ftrace_entry *entry;
unsigned long flags;
long disabled;
int resched;
int cpu;
int pc;
pc = preempt_count();
resched = ftrace_preempt_disable();
cpu = raw_smp_processor_id();
disabled = atomic_inc_return(&per_cpu(test_event_disable, cpu));
if (disabled != 1)
goto out;
local_save_flags(flags);
event = trace_current_buffer_lock_reserve(TRACE_FN, sizeof(*entry),
flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
trace_nowake_buffer_unlock_commit(event, flags, pc);
out:
atomic_dec(&per_cpu(test_event_disable, cpu));
ftrace_preempt_enable(resched);
}
static struct ftrace_ops trace_ops __initdata =
{
.func = function_test_events_call,
};
static __init void event_trace_self_test_with_function(void)
{
register_ftrace_function(&trace_ops);
pr_info("Running tests again, along with the function tracer\n");
event_trace_self_tests();
unregister_ftrace_function(&trace_ops);
}
#else
static __init void event_trace_self_test_with_function(void)
{
}
#endif
static __init int event_trace_self_tests_init(void)
{
if (!tracing_selftest_disabled) {
event_trace_self_tests();
event_trace_self_test_with_function();
}
return 0;
}
late_initcall(event_trace_self_tests_init);
#endif