arch/sparc/oprofile/init.c

   1 /**
   2  * @file init.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/oprofile.h>
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14
  15 #ifdef CONFIG_SPARC64
  16 #include <linux/notifier.h>
  17 #include <linux/rcupdate.h>
  18 #include <linux/kdebug.h>
  19 #include <asm/nmi.h>
  20
  21 static int profile_timer_exceptions_notify(struct notifier_block *self,
  22                                            unsigned long val, void *data)
  23 {
  24         struct die_args *args = data;
  25         int ret = NOTIFY_DONE;
  26
  27         switch (val) {
  28         case DIE_NMI:
  29                 oprofile_add_sample(args->regs, 0);
  30                 ret = NOTIFY_STOP;
  31                 break;
  32         default:
  33                 break;
  34         }
  35         return ret;
  36 }
  37
  38 static struct notifier_block profile_timer_exceptions_nb = {
  39         .notifier_call  = profile_timer_exceptions_notify,
  40 };
  41
  42 static int timer_start(void)
  43 {
  44         if (register_die_notifier(&profile_timer_exceptions_nb))
  45                 return 1;
  46         nmi_adjust_hz(HZ);
  47         return 0;
  48 }
  49
  50
  51 static void timer_stop(void)
  52 {
  53         nmi_adjust_hz(1);
  54         unregister_die_notifier(&profile_timer_exceptions_nb);
  55         synchronize_sched();  /* Allow already-started NMIs to complete. */
  56 }
  57
  58 static int op_nmi_timer_init(struct oprofile_operations *ops)
  59 {
  60         if (atomic_read(&nmi_active) <= 0)
  61                 return -ENODEV;
  62
  63         ops->start = timer_start;
  64         ops->stop = timer_stop;
  65         ops->cpu_type = "timer";
  66         printk(KERN_INFO "oprofile: Using perfctr NMI timer interrupt.\n");
  67         return 0;
  68 }
  69 #endif
  70
  71 int __init oprofile_arch_init(struct oprofile_operations *ops)
  72 {
  73         int ret = -ENODEV;
  74
  75 #ifdef CONFIG_SPARC64
  76         ret = op_nmi_timer_init(ops);
  77         if (!ret)
  78                 return ret;
  79 #endif
  80
  81         return ret;
  82 }
  83
  84 void oprofile_arch_exit(void)
  85 {
  86 }