/** * @file nmi_timer_int.c * * @remark Copyright 2003 OProfile authors * @remark Read the file COPYING * * @author Zwane Mwaikambo <zwane@linuxpower.ca> */ #include <linux/init.h> #include <linux/smp.h> #include <linux/errno.h> #include <linux/oprofile.h> #include <linux/rcupdate.h> #include <linux/kdebug.h> #include <asm/nmi.h> #include <asm/apic.h> #include <asm/ptrace.h> static int profile_timer_exceptions_notify(struct notifier_block *self, unsigned long val, void *data) { struct die_args *args = (struct die_args *)data; int ret = NOTIFY_DONE; switch (val) { case DIE_NMI: oprofile_add_sample(args->regs, 0); ret = NOTIFY_STOP; break; default: break; } return ret; } static struct notifier_block profile_timer_exceptions_nb = { .notifier_call = profile_timer_exceptions_notify, .next = NULL, .priority = 0 }; static int timer_start(void) { if (register_die_notifier(&profile_timer_exceptions_nb)) return 1; return 0; } static void timer_stop(void) { unregister_die_notifier(&profile_timer_exceptions_nb); synchronize_sched(); /* Allow already-started NMIs to complete. */ } int __init op_nmi_timer_init(struct oprofile_operations *ops) { if ((nmi_watchdog != NMI_IO_APIC) || (atomic_read(&nmi_active) <= 0)) return -ENODEV; ops->start = timer_start; ops->stop = timer_stop; ops->cpu_type = "timer"; printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); return 0; }