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
  25 static enum hrtimer_restart oprofile_hrtimer_notify(struct hrtimer *hrtimer)
  26 {
  27         oprofile_add_sample(get_irq_regs(), 0);
  28         hrtimer_forward_now(hrtimer, ns_to_ktime(TICK_NSEC));
  29         return HRTIMER_RESTART;
  30 }
  31
  32 static void __oprofile_hrtimer_start(void *unused)
  33 {
  34         struct hrtimer *hrtimer = &__get_cpu_var(oprofile_hrtimer);
  35
  36         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  37         hrtimer->function = oprofile_hrtimer_notify;
  38
  39         hrtimer_start(hrtimer, ns_to_ktime(TICK_NSEC),
  40                       HRTIMER_MODE_REL_PINNED);
  41 }
  42
  43 static int oprofile_hrtimer_start(void)
  44 {
  45         on_each_cpu(__oprofile_hrtimer_start, NULL, 1);
  46         return 0;
  47 }
  48
  49 static void __oprofile_hrtimer_stop(int cpu)
  50 {
  51         struct hrtimer *hrtimer = &per_cpu(oprofile_hrtimer, cpu);
  52
  53         hrtimer_cancel(hrtimer);
  54 }
  55
  56 static void oprofile_hrtimer_stop(void)
  57 {
  58         int cpu;
  59
  60         for_each_online_cpu(cpu)
  61                 __oprofile_hrtimer_stop(cpu);
  62 }
  63
  64 static int __cpuinit oprofile_cpu_notify(struct notifier_block *self,
  65                                          unsigned long action, void *hcpu)
  66 {
  67         long cpu = (long) hcpu;
  68
  69         switch (action) {
  70         case CPU_ONLINE:
  71         case CPU_ONLINE_FROZEN:
  72                 smp_call_function_single(cpu, __oprofile_hrtimer_start,
  73                                          NULL, 1);
  74                 break;
  75         case CPU_DEAD:
  76         case CPU_DEAD_FROZEN:
  77                 __oprofile_hrtimer_stop(cpu);
  78                 break;
  79         }
  80         return NOTIFY_OK;
  81 }
  82
  83 static struct notifier_block __refdata oprofile_cpu_notifier = {
  84         .notifier_call = oprofile_cpu_notify,
  85 };
  86
  87 int __init oprofile_timer_init(struct oprofile_operations *ops)
  88 {
  89         int rc;
  90
  91         rc = register_hotcpu_notifier(&oprofile_cpu_notifier);
  92         if (rc)
  93                 return rc;
  94         ops->create_files = NULL;
  95         ops->setup = NULL;
  96         ops->shutdown = NULL;
  97         ops->start = oprofile_hrtimer_start;
  98         ops->stop = oprofile_hrtimer_stop;
  99         ops->cpu_type = "timer";
 100         return 0;
 101 }
 102
 103 void __exit oprofile_timer_exit(void)
 104 {
 105         unregister_hotcpu_notifier(&oprofile_cpu_notifier);
 106 }