blob: 8fa73ae301a95c8300acc3f968d3ac598e6c0ea8 [file] [log] [blame]
/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <asm/thread_notify.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#define CREATE_TRACE_POINTS
#include "perf_trace_counters.h"
static unsigned int tp_pid_state;
static int tracectr_notifier(struct notifier_block *self, unsigned long cmd,
void *v)
{
static int old_pid = -1;
struct thread_info *thread = v;
int current_pid;
if (cmd != THREAD_NOTIFY_SWITCH)
return old_pid;
current_pid = thread->task->pid;
if (old_pid != -1)
trace_sched_switch_with_ctrs(old_pid, current_pid);
old_pid = current_pid;
return old_pid;
}
static struct notifier_block tracectr_notifier_block = {
.notifier_call = tracectr_notifier,
};
static void enable_tp_pid(void)
{
if (tp_pid_state == 0) {
tp_pid_state = 1;
thread_register_notifier(&tracectr_notifier_block);
}
}
static void disable_tp_pid(void)
{
if (tp_pid_state == 1) {
tp_pid_state = 0;
thread_unregister_notifier(&tracectr_notifier_block);
}
}
static ssize_t read_enabled_perftp_file_bool(struct file *file,
char __user *user_buf, size_t count, loff_t *ppos)
{
char buf[2];
buf[1] = '\n';
if (tp_pid_state == 0)
buf[0] = '0';
else
buf[0] = '1';
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
static ssize_t write_enabled_perftp_file_bool(struct file *file,
const char __user *user_buf, size_t count, loff_t *ppos)
{
char buf[32];
size_t buf_size;
buf_size = min(count, (sizeof(buf)-1));
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
switch (buf[0]) {
case 'y':
case 'Y':
case '1':
enable_tp_pid();
break;
case 'n':
case 'N':
case '0':
disable_tp_pid();
break;
}
return count;
}
static const struct file_operations fops_perftp = {
.read = read_enabled_perftp_file_bool,
.write = write_enabled_perftp_file_bool,
.llseek = default_llseek,
};
int __init init_tracecounters(void)
{
struct dentry *dir;
struct dentry *file;
unsigned int value = 1;
dir = debugfs_create_dir("perf_debug_tp", NULL);
if (!dir)
return -ENOMEM;
file = debugfs_create_file("enabled", 0660, dir,
&value, &fops_perftp);
if (!file) {
debugfs_remove(dir);
return -ENOMEM;
}
return 0;
}
late_initcall(init_tracecounters);