arch/x86/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 #include <linux/kdebug.h>
  16
  17 #include <asm/nmi.h>
  18 #include <asm/apic.h>
  19 #include <asm/ptrace.h>
  20
  21 static int profile_timer_exceptions_notify(unsigned int val, struct pt_regs *regs)
  22 {
  23         oprofile_add_sample(regs, 0);
  24         return NMI_HANDLED;
  25 }
  26
  27 static int timer_start(void)
  28 {
  29         if (register_nmi_handler(NMI_LOCAL, profile_timer_exceptions_notify,
  30                                         0, "oprofile-timer"))
  31                 return 1;
  32         return 0;
  33 }
  34
  35
  36 static void timer_stop(void)
  37 {
  38         unregister_nmi_handler(NMI_LOCAL, "oprofile-timer");
  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         ops->start = timer_start;
  46         ops->stop = timer_stop;
  47         ops->cpu_type = "timer";
  48         printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
  49         return 0;
  50 }