| /* 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", 0777, dir, |
| &value, &fops_perftp); |
| if (!file) { |
| debugfs_remove(dir); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| late_initcall(init_tracecounters); |