1 /** 2 * @file timer_int.c 3 * 4 * @remark Copyright 2002 OProfile authors 5 * @remark Read the file COPYING 6 * 7 * @author John Levon <levon@movementarian.org> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/notifier.h> 12 #include <linux/smp.h> 13 #include <linux/oprofile.h> 14 #include <linux/profile.h> 15 #include <linux/init.h> 16 #include <linux/cpu.h> 17 #include <linux/hrtimer.h> 18 #include <asm/irq_regs.h> 19 #include <asm/ptrace.h> 20 21 #include "oprof.h" 22 23 static DEFINE_PER_CPU(struct hrtimer, oprofile_hrtimer); 24 static int ctr_running; 25 oprofile_hrtimer_notify(struct hrtimer * hrtimer)26 static enum hrtimer_restart oprofile_hrtimer_notify(struct hrtimer *hrtimer) 27 { 28 oprofile_add_sample(get_irq_regs(), 0); 29 hrtimer_forward_now(hrtimer, ns_to_ktime(TICK_NSEC)); 30 return HRTIMER_RESTART; 31 } 32 __oprofile_hrtimer_start(void * unused)33 static void __oprofile_hrtimer_start(void *unused) 34 { 35 struct hrtimer *hrtimer = this_cpu_ptr(&oprofile_hrtimer); 36 37 if (!ctr_running) 38 return; 39 40 hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 41 hrtimer->function = oprofile_hrtimer_notify; 42 43 hrtimer_start(hrtimer, ns_to_ktime(TICK_NSEC), 44 HRTIMER_MODE_REL_PINNED); 45 } 46 oprofile_hrtimer_start(void)47 static int oprofile_hrtimer_start(void) 48 { 49 get_online_cpus(); 50 ctr_running = 1; 51 on_each_cpu(__oprofile_hrtimer_start, NULL, 1); 52 put_online_cpus(); 53 return 0; 54 } 55 __oprofile_hrtimer_stop(int cpu)56 static void __oprofile_hrtimer_stop(int cpu) 57 { 58 struct hrtimer *hrtimer = &per_cpu(oprofile_hrtimer, cpu); 59 60 if (!ctr_running) 61 return; 62 63 hrtimer_cancel(hrtimer); 64 } 65 oprofile_hrtimer_stop(void)66 static void oprofile_hrtimer_stop(void) 67 { 68 int cpu; 69 70 get_online_cpus(); 71 for_each_online_cpu(cpu) 72 __oprofile_hrtimer_stop(cpu); 73 ctr_running = 0; 74 put_online_cpus(); 75 } 76 oprofile_timer_online(unsigned int cpu)77 static int oprofile_timer_online(unsigned int cpu) 78 { 79 local_irq_disable(); 80 __oprofile_hrtimer_start(NULL); 81 local_irq_enable(); 82 return 0; 83 } 84 oprofile_timer_prep_down(unsigned int cpu)85 static int oprofile_timer_prep_down(unsigned int cpu) 86 { 87 __oprofile_hrtimer_stop(cpu); 88 return 0; 89 } 90 91 static enum cpuhp_state hp_online; 92 oprofile_hrtimer_setup(void)93 static int oprofile_hrtimer_setup(void) 94 { 95 int ret; 96 97 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 98 "oprofile/timer:online", 99 oprofile_timer_online, 100 oprofile_timer_prep_down); 101 if (ret < 0) 102 return ret; 103 hp_online = ret; 104 return 0; 105 } 106 oprofile_hrtimer_shutdown(void)107 static void oprofile_hrtimer_shutdown(void) 108 { 109 cpuhp_remove_state_nocalls(hp_online); 110 } 111 oprofile_timer_init(struct oprofile_operations * ops)112 int oprofile_timer_init(struct oprofile_operations *ops) 113 { 114 ops->create_files = NULL; 115 ops->setup = oprofile_hrtimer_setup; 116 ops->shutdown = oprofile_hrtimer_shutdown; 117 ops->start = oprofile_hrtimer_start; 118 ops->stop = oprofile_hrtimer_stop; 119 ops->cpu_type = "timer"; 120 printk(KERN_INFO "oprofile: using timer interrupt.\n"); 121 return 0; 122 } 123