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/irq.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         unsigned long eip = instruction_pointer(regs);
  24
  25         oprofile_add_sample(eip, !user_mode(regs), 0, cpu);
  26         return 1;
  27 }
  28
  29 static int timer_start(void)
  30 {
  31         disable_timer_nmi_watchdog();
  32         set_nmi_callback(nmi_timer_callback);
  33         return 0;
  34 }
  35
  36
  37 static void timer_stop(void)
  38 {
  39         enable_timer_nmi_watchdog();
  40         unset_nmi_callback();
  41         synchronize_kernel();
  42 }
  43
  44
  45 static struct oprofile_operations nmi_timer_ops = {
  46         .start  = timer_start,
  47         .stop   = timer_stop,
  48         .cpu_type = "timer"
  49 };
  50
  51 int __init nmi_timer_init(struct oprofile_operations ** ops)
  52 {
  53         extern int nmi_active;
  54
  55         if (nmi_active <= 0)
  56                 return -ENODEV;
  57
  58         *ops = &nmi_timer_ops;
  59         printk(KERN_INFO "oprofile: using NMI timer interrupt.\n");
  60         return 0;
  61 }