linux/kernel/trace/trace_events.c
Steven Rostedt 553552ce17 tracing: Combine event filter_active and enable into single flags field
The filter_active and enable both use an int (4 bytes each) to
set a single flag. We can save 4 bytes per event by combining the
two into a single integer.

   text	   data	    bss	    dec	    hex	filename
4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
4894944	1018052	 861512	6774508	 675eec	vmlinux.id
4894871	1012292	 861512	6768675	 674823	vmlinux.flags

This gives us another 5K in savings.

The modification of both the enable and filter fields are done
under the event_mutex, so it is still safe to combine the two.

Note: Although Mathieu gave his Acked-by, he would like it documented
 that the reads of flags are not protected by the mutex. The way the
 code works, these reads will not break anything, but will have a
 residual effect. Since this behavior is the same even before this
 patch, describing this situation is left to another patch, as this
 patch does not change the behavior, but just brought it to Mathieu's
 attention.

v2: Updated the event trace self test to for this change.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-05-14 14:33:22 -04:00

1587 lines
34 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/slab.h>
#include <linux/delay.h>
#include <asm/setup.h>
#include "trace_output.h"
#undef TRACE_SYSTEM
#define TRACE_SYSTEM "TRACE_SYSTEM"
DEFINE_MUTEX(event_mutex);
LIST_HEAD(ftrace_events);
struct list_head *
trace_get_fields(struct ftrace_event_call *event_call)
{
if (!event_call->class->get_fields)
return &event_call->class->fields;
return event_call->class->get_fields(event_call);
}
int trace_define_field(struct ftrace_event_call *call, const char *type,
const char *name, int offset, int size, int is_signed,
int filter_type)
{
struct ftrace_event_field *field;
struct list_head *head;
if (WARN_ON(!call->class))
return 0;
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;
if (filter_type == FILTER_OTHER)
field->filter_type = filter_assign_type(type);
else
field->filter_type = filter_type;
field->offset = offset;
field->size = size;
field->is_signed = is_signed;
head = trace_get_fields(call);
list_add(&field->link, head);
return 0;
err:
if (field)
kfree(field->name);
kfree(field);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(trace_define_field);
#define __common_field(type, item) \
ret = trace_define_field(call, #type, "common_" #item, \
offsetof(typeof(ent), item), \
sizeof(ent.item), \
is_signed_type(type), FILTER_OTHER); \
if (ret) \
return ret;
static int trace_define_common_fields(struct ftrace_event_call *call)
{
int ret;
struct trace_entry ent;
__common_field(unsigned short, type);
__common_field(unsigned char, flags);
__common_field(unsigned char, preempt_count);
__common_field(int, pid);
__common_field(int, lock_depth);
return ret;
}
void trace_destroy_fields(struct ftrace_event_call *call)
{
struct ftrace_event_field *field, *next;
struct list_head *head;
head = trace_get_fields(call);
list_for_each_entry_safe(field, next, head, link) {
list_del(&field->link);
kfree(field->type);
kfree(field->name);
kfree(field);
}
}
int trace_event_raw_init(struct ftrace_event_call *call)
{
int id;
id = register_ftrace_event(&call->event);
if (!id)
return -ENODEV;
return 0;
}
EXPORT_SYMBOL_GPL(trace_event_raw_init);
static int ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
int ret = 0;
switch (enable) {
case 0:
if (call->flags & TRACE_EVENT_FL_ENABLED) {
call->flags &= ~TRACE_EVENT_FL_ENABLED;
tracing_stop_cmdline_record();
if (call->class->reg)
call->class->reg(call, TRACE_REG_UNREGISTER);
else
tracepoint_probe_unregister(call->name,
call->class->probe,
call);
}
break;
case 1:
if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
tracing_start_cmdline_record();
if (call->class->reg)
ret = call->class->reg(call, TRACE_REG_REGISTER);
else
ret = tracepoint_probe_register(call->name,
call->class->probe,
call);
if (ret) {
tracing_stop_cmdline_record();
pr_info("event trace: Could not enable event "
"%s\n", call->name);
break;
}
call->flags |= TRACE_EVENT_FL_ENABLED;
}
break;
}
return ret;
}
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->class ||
(!call->class->probe && !call->class->reg))
continue;
if (match &&
strcmp(match, call->name) != 0 &&
strcmp(match, call->class->system) != 0)
continue;
if (sub && strcmp(sub, call->class->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)
{
struct trace_parser parser;
ssize_t read, ret;
if (!cnt)
return 0;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
return -ENOMEM;
read = trace_get_user(&parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded((&parser))) {
int set = 1;
if (*parser.buffer == '!')
set = 0;
parser.buffer[parser.idx] = 0;
ret = ftrace_set_clr_event(parser.buffer + !set, set);
if (ret)
goto out_put;
}
ret = read;
out_put:
trace_parser_put(&parser);
return ret;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_event_call *call = v;
(*pos)++;
list_for_each_entry_continue(call, &ftrace_events, list) {
/*
* The ftrace subsystem is for showing formats only.
* They can not be enabled or disabled via the event files.
*/
if (call->class && (call->class->probe || call->class->reg))
return call;
}
return NULL;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_event_call *call;
loff_t l;
mutex_lock(&event_mutex);
call = list_entry(&ftrace_events, struct ftrace_event_call, list);
for (l = 0; l <= *pos; ) {
call = t_next(m, call, &l);
if (!call)
break;
}
return call;
}
static void *
s_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_event_call *call = v;
(*pos)++;
list_for_each_entry_continue(call, &ftrace_events, list) {
if (call->flags & TRACE_EVENT_FL_ENABLED)
return call;
}
return NULL;
}
static void *s_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_event_call *call;
loff_t l;
mutex_lock(&event_mutex);
call = list_entry(&ftrace_events, struct ftrace_event_call, list);
for (l = 0; l <= *pos; ) {
call = s_next(m, call, &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->class->system, TRACE_SYSTEM) != 0)
seq_printf(m, "%s:", call->class->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_TRUNC))
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->flags & TRACE_EVENT_FL_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);
ret = ftrace_event_enable_disable(call, val);
mutex_unlock(&event_mutex);
break;
default:
return -EINVAL;
}
*ppos += cnt;
return ret ? ret : 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->class ||
(!call->class->probe && !call->class->reg))
continue;
if (system && strcmp(call->class->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->flags & TRACE_EVENT_FL_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;
}
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 ftrace_event_field *field;
struct list_head *head;
struct trace_seq *s;
int common_field_count = 5;
char *buf;
int r = 0;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
trace_seq_printf(s, "name: %s\n", call->name);
trace_seq_printf(s, "ID: %d\n", call->event.type);
trace_seq_printf(s, "format:\n");
head = trace_get_fields(call);
list_for_each_entry_reverse(field, head, link) {
/*
* Smartly shows the array type(except dynamic array).
* Normal:
* field:TYPE VAR
* If TYPE := TYPE[LEN], it is shown:
* field:TYPE VAR[LEN]
*/
const char *array_descriptor = strchr(field->type, '[');
if (!strncmp(field->type, "__data_loc", 10))
array_descriptor = NULL;
if (!array_descriptor) {
r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
"\tsize:%u;\tsigned:%d;\n",
field->type, field->name, field->offset,
field->size, !!field->is_signed);
} else {
r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
"\tsize:%u;\tsigned:%d;\n",
(int)(array_descriptor - field->type),
field->type, field->name,
array_descriptor, field->offset,
field->size, !!field->is_signed);
}
if (--common_field_count == 0)
r = trace_seq_printf(s, "\n");
if (!r)
break;
}
if (r)
r = trace_seq_printf(s, "\nprint fmt: %s\n",
call->print_fmt);
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->event.type);
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);
}
trace_create_file("enable", 0644, system->entry,
(void *)system->name,
&ftrace_system_enable_fops);
return system->entry;
}
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 list_head *head;
int ret;
/*
* If the trace point header did not define TRACE_SYSTEM
* then the system would be called "TRACE_SYSTEM".
*/
if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
d_events = event_subsystem_dir(call->class->system, d_events);
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->class->probe || call->class->reg)
trace_create_file("enable", 0644, call->dir, call,
enable);
#ifdef CONFIG_PERF_EVENTS
if (call->event.type && (call->class->perf_probe || call->class->reg))
trace_create_file("id", 0444, call->dir, call,
id);
#endif
if (call->class->define_fields) {
/*
* Other events may have the same class. Only update
* the fields if they are not already defined.
*/
head = trace_get_fields(call);
if (list_empty(head)) {
ret = trace_define_common_fields(call);
if (!ret)
ret = call->class->define_fields(call);
if (ret < 0) {
pr_warning("Could not initialize trace point"
" events/%s\n", call->name);
return ret;
}
}
trace_create_file("filter", 0644, call->dir, call,
filter);
}
trace_create_file("format", 0444, call->dir, call,
format);
return 0;
}
static int __trace_add_event_call(struct ftrace_event_call *call)
{
struct dentry *d_events;
int ret;
if (!call->name)
return -EINVAL;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
"events/%s\n", call->name);
return ret;
}
}
d_events = event_trace_events_dir();
if (!d_events)
return -ENOENT;
ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
&ftrace_enable_fops, &ftrace_event_filter_fops,
&ftrace_event_format_fops);
if (!ret)
list_add(&call->list, &ftrace_events);
return ret;
}
/* Add an additional event_call dynamically */
int trace_add_event_call(struct ftrace_event_call *call)
{
int ret;
mutex_lock(&event_mutex);
ret = __trace_add_event_call(call);
mutex_unlock(&event_mutex);
return ret;
}
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;
}
}
}
/*
* Must be called under locking both of event_mutex and trace_event_mutex.
*/
static void __trace_remove_event_call(struct ftrace_event_call *call)
{
ftrace_event_enable_disable(call, 0);
if (call->event.funcs)
__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->class->system);
}
/* Remove an event_call */
void trace_remove_event_call(struct ftrace_event_call *call)
{
mutex_lock(&event_mutex);
down_write(&trace_event_mutex);
__trace_remove_event_call(call);
up_write(&trace_event_mutex);
mutex_unlock(&event_mutex);
}
#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;
int ret;
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;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
"point events/%s\n", 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;
ret = event_create_dir(call, d_events,
&file_ops->id, &file_ops->enable,
&file_ops->filter, &file_ops->format);
if (!ret)
list_add(&call->list, &ftrace_events);
}
}
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;
__trace_remove_event_call(call);
}
}
/* 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 */
static 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;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
"point events/%s\n", call->name);
continue;
}
}
ret = event_create_dir(call, d_events, &ftrace_event_id_fops,
&ftrace_enable_fops,
&ftrace_event_filter_fops,
&ftrace_event_format_fops);
if (!ret)
list_add(&call->list, &ftrace_events);
}
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 probe */
if (!call->class || !call->class->probe)
continue;
/*
* Testing syscall events here is pretty useless, but
* we still do it if configured. But this is time consuming.
* What we really need is a user thread to perform the
* syscalls as we test.
*/
#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
if (call->class->system &&
strcmp(call->class->system, "syscalls") == 0)
continue;
#endif
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->flags & TRACE_EVENT_FL_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, ftrace_test_event_disable);
static void
function_test_events_call(unsigned long ip, unsigned long parent_ip)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
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(ftrace_test_event_disable, cpu));
if (disabled != 1)
goto out;
local_save_flags(flags);
event = trace_current_buffer_lock_reserve(&buffer,
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(buffer, event, flags, pc);
out:
atomic_dec(&per_cpu(ftrace_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