1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * cpuidle driver for haltpoll governor. 4 * 5 * Copyright 2019 Red Hat, Inc. and/or its affiliates. 6 * 7 * This work is licensed under the terms of the GNU GPL, version 2. See 8 * the COPYING file in the top-level directory. 9 * 10 * Authors: Marcelo Tosatti <mtosatti@redhat.com> 11 */ 12 13 #include <linux/init.h> 14 #include <linux/cpuidle.h> 15 #include <linux/module.h> 16 #include <linux/sched/idle.h> 17 #include <linux/kvm_para.h> 18 19 static int default_enter_idle(struct cpuidle_device *dev, 20 struct cpuidle_driver *drv, int index) 21 { 22 if (current_clr_polling_and_test()) { 23 local_irq_enable(); 24 return index; 25 } 26 default_idle(); 27 return index; 28 } 29 30 static struct cpuidle_driver haltpoll_driver = { 31 .name = "haltpoll", 32 .owner = THIS_MODULE, 33 .states = { 34 { /* entry 0 is for polling */ }, 35 { 36 .enter = default_enter_idle, 37 .exit_latency = 1, 38 .target_residency = 1, 39 .power_usage = -1, 40 .name = "haltpoll idle", 41 .desc = "default architecture idle", 42 }, 43 }, 44 .safe_state_index = 0, 45 .state_count = 2, 46 }; 47 48 static int __init haltpoll_init(void) 49 { 50 struct cpuidle_driver *drv = &haltpoll_driver; 51 52 cpuidle_poll_state_init(drv); 53 54 if (!kvm_para_available()) 55 return 0; 56 57 return cpuidle_register(&haltpoll_driver, NULL); 58 } 59 60 static void __exit haltpoll_exit(void) 61 { 62 cpuidle_unregister(&haltpoll_driver); 63 } 64 65 module_init(haltpoll_init); 66 module_exit(haltpoll_exit); 67 MODULE_LICENSE("GPL"); 68 MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>"); 69