arch/i386/oprofile/nmi_timer_int.c

   1 /**
   2  * @file nmi_timer_int.c
   3  *
   4  * @remark Copyright 2003 OProfile authors
   5  * @remark Read the file COPYING
   6  *
   7  * @author Zwane Mwaikambo <zwane@linuxpower.ca>
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/smp.h>
  12 #include <linux/errno.h>
  13 #include <linux/oprofile.h>
  14 #include <linux/rcupdate.h>
  15
  16
  17 #include <asm/nmi.h>
  18 #include <asm/apic.h>
  19 #include <asm/ptrace.h>
  20
  21 static int nmi_timer_callback(struct pt_regs * regs, int cpu)
  22 {
  23         oprofile_add_sample(regs, 0);
  24         return 1;
  25 }
  26
  27 static int timer_start(void)
  28 {
  29         disable_timer_nmi_watchdog();
  30         set_nmi_callback(nmi_timer_callback);
  31         return 0;
  32 }
  33
  34
  35 static void timer_stop(void)
  36 {
  37         enable_timer_nmi_watchdog();
  38         unset_nmi_callback();
  39         synchronize_sched();  /* Allow already-started NMIs to complete. */
  40 }
  41
  42
  43 int __init op_nmi_timer_init(struct oprofile_operations * ops)
  44 {
  45         extern int nmi_active;
  46
  47         if (nmi_active <= 0)
  48                 return -ENODEV;
  49
  50         ops->start = timer_start;
  51         ops->stop = timer_stop;
  52         ops->cpu_type = "timer";
  53         printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
  54         return 0;
  55 }