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 = 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
  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 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
  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
  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
 107 static void oprofile_hrtimer_shutdown(void)
 108 {
 109         cpuhp_remove_state_nocalls(hp_online);
 110 }
 111
 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 }