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 21static int profile_timer_exceptions_notify(struct notifier_block *self, 22 unsigned long val, void *data) 23{ 24 struct die_args *args = (struct die_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 38static struct notifier_block profile_timer_exceptions_nb = { 39 .notifier_call = profile_timer_exceptions_notify, 40 .next = NULL, 41 .priority = 0 42}; 43 44static int timer_start(void) 45{ 46 if (register_die_notifier(&profile_timer_exceptions_nb)) 47 return 1; 48 return 0; 49} 50 51 52static void timer_stop(void) 53{ 54 unregister_die_notifier(&profile_timer_exceptions_nb); 55 synchronize_sched(); /* Allow already-started NMIs to complete. */ 56} 57 58 59int __init op_nmi_timer_init(struct oprofile_operations *ops) 60{ 61 if ((nmi_watchdog != NMI_IO_APIC) || (atomic_read(&nmi_active) <= 0)) 62 return -ENODEV; 63 64 ops->start = timer_start; 65 ops->stop = timer_stop; 66 ops->cpu_type = "timer"; 67 printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); 68 return 0; 69} 70