drivers/oprofile/timer_int.c

   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
  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
  33 static void __oprofile_hrtimer_start(void *unused)
  34 {
  35         struct hrtimer *hrtimer = &__get_cpu_var(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
  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
  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
  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
  77 static int __cpuinit oprofile_cpu_notify(struct notifier_block *self,
  78                                          unsigned long action, void *hcpu)
  79 {
  80         long cpu = (long) hcpu;
  81
  82         switch (action) {
  83         case CPU_ONLINE:
  84         case CPU_ONLINE_FROZEN:
  85                 smp_call_function_single(cpu, __oprofile_hrtimer_start,
  86                                          NULL, 1);
  87                 break;
  88         case CPU_DEAD:
  89         case CPU_DEAD_FROZEN:
  90                 __oprofile_hrtimer_stop(cpu);
  91                 break;
  92         }
  93         return NOTIFY_OK;
  94 }
  95
  96 static struct notifier_block __refdata oprofile_cpu_notifier = {
  97         .notifier_call = oprofile_cpu_notify,
  98 };
  99
 100 int oprofile_timer_init(struct oprofile_operations *ops)
 101 {
 102         int rc;
 103
 104         rc = register_hotcpu_notifier(&oprofile_cpu_notifier);
 105         if (rc)
 106                 return rc;
 107         ops->create_files = NULL;
 108         ops->setup = NULL;
 109         ops->shutdown = NULL;
 110         ops->start = oprofile_hrtimer_start;
 111         ops->stop = oprofile_hrtimer_stop;
 112         ops->cpu_type = "timer";
 113         printk(KERN_INFO "oprofile: using timer interrupt.\n");
 114         return 0;
 115 }
 116
 117 void oprofile_timer_exit(void)
 118 {
 119         unregister_hotcpu_notifier(&oprofile_cpu_notifier);
 120 }