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/**
* @file oprof.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon <levon@movementarian.org>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/oprofile.h>
#include <linux/moduleparam.h>
#include <asm/mutex.h>
#include "oprof.h"
#include "event_buffer.h"
#include "cpu_buffer.h"
#include "buffer_sync.h"
#include "oprofile_stats.h"
struct oprofile_operations oprofile_ops;
unsigned long oprofile_started;
unsigned long oprofile_backtrace_depth;
static unsigned long is_setup;
static DEFINE_MUTEX(start_mutex);
/* timer
0 - use performance monitoring hardware if available
1 - use the timer int mechanism regardless
*/
static int timer = 0;
int oprofile_setup(void)
{
int err;
mutex_lock(&start_mutex);
if ((err = alloc_cpu_buffers()))
goto out;
if ((err = alloc_event_buffer()))
goto out1;
if (oprofile_ops.setup && (err = oprofile_ops.setup()))
goto out2;
/* Note even though this starts part of the
* profiling overhead, it's necessary to prevent
* us missing task deaths and eventually oopsing
* when trying to process the event buffer.
*/
if (oprofile_ops.sync_start) {
int sync_ret = oprofile_ops.sync_start();
switch (sync_ret) {
case 0:
goto post_sync;
case 1:
goto do_generic;
case -1:
goto out3;
default:
goto out3;
}
}
do_generic:
if ((err = sync_start()))
goto out3;
post_sync:
is_setup = 1;
mutex_unlock(&start_mutex);
return 0;
out3:
if (oprofile_ops.shutdown)
oprofile_ops.shutdown();
out2:
free_event_buffer();
out1:
free_cpu_buffers();
out:
mutex_unlock(&start_mutex);
return err;
}
/* Actually start profiling (echo 1>/dev/oprofile/enable) */
int oprofile_start(void)
{
int err = -EINVAL;
mutex_lock(&start_mutex);
if (!is_setup)
goto out;
err = 0;
if (oprofile_started)
goto out;
oprofile_reset_stats();
if ((err = oprofile_ops.start()))
goto out;
oprofile_started = 1;
out:
mutex_unlock(&start_mutex);
return err;
}
/* echo 0>/dev/oprofile/enable */
void oprofile_stop(void)
{
mutex_lock(&start_mutex);
if (!oprofile_started)
goto out;
oprofile_ops.stop();
oprofile_started = 0;
/* wake up the daemon to read what remains */
wake_up_buffer_waiter();
out:
mutex_unlock(&start_mutex);
}
void oprofile_shutdown(void)
{
mutex_lock(&start_mutex);
if (oprofile_ops.sync_stop) {
int sync_ret = oprofile_ops.sync_stop();
switch (sync_ret) {
case 0:
goto post_sync;
case 1:
goto do_generic;
default:
goto post_sync;
}
}
do_generic:
sync_stop();
post_sync:
if (oprofile_ops.shutdown)
oprofile_ops.shutdown();
is_setup = 0;
free_event_buffer();
free_cpu_buffers();
mutex_unlock(&start_mutex);
}
int oprofile_set_backtrace(unsigned long val)
{
int err = 0;
mutex_lock(&start_mutex);
if (oprofile_started) {
err = -EBUSY;
goto out;
}
if (!oprofile_ops.backtrace) {
err = -EINVAL;
goto out;
}
oprofile_backtrace_depth = val;
out:
mutex_unlock(&start_mutex);
return err;
}
static int __init oprofile_init(void)
{
int err;
err = oprofile_arch_init(&oprofile_ops);
if (err < 0 || timer) {
printk(KERN_INFO "oprofile: using timer interrupt.\n");
oprofile_timer_init(&oprofile_ops);
}
err = oprofilefs_register();
if (err)
oprofile_arch_exit();
return err;
}
static void __exit oprofile_exit(void)
{
oprofilefs_unregister();
oprofile_arch_exit();
}
module_init(oprofile_init);
module_exit(oprofile_exit);
module_param_named(timer, timer, int, 0644);
MODULE_PARM_DESC(timer, "force use of timer interrupt");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Levon <levon@movementarian.org>");
MODULE_DESCRIPTION("OProfile system profiler");
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