init.c

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#include <linux/kernel.h>
#include <linux/oprofile.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/param.h>    /* for HZ */
 
#ifdef CONFIG_SPARC64
#include <linux/notifier.h>
#include <linux/rcupdate.h>
#include <linux/kdebug.h>
#include <asm/nmi.h>

static int profile_timer_exceptions_notify(struct notifier_block *self,
                       unsigned long val, void *data)
{
    struct die_args *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,
};

static int timer_start(void)
{
    if (register_die_notifier(&profile_timer_exceptions_nb))
        return 1;
    nmi_adjust_hz(HZ);
    return 0;
}


static void timer_stop(void)
{
    nmi_adjust_hz(1);
    unregister_die_notifier(&profile_timer_exceptions_nb);
    synchronize_sched();  /* Allow already-started NMIs to complete. */
}

static int op_nmi_timer_init(struct oprofile_operations *ops)
{
    if (atomic_read(&nmi_active) <= 0)
        return -ENODEV;

    ops->start = timer_start;
    ops->stop = timer_stop;
    ops->cpu_type = "timer";
    printk(KERN_INFO "oprofile: Using perfctr NMI timer interrupt.\n");
    return 0;
}
#endif

int __init oprofile_arch_init(struct oprofile_operations *ops)
{
    int ret = -ENODEV;

#ifdef CONFIG_SPARC64
    ret = op_nmi_timer_init(ops);
    if (!ret)
        return ret;
#endif

    return ret;
}

void oprofile_arch_exit(void)
{
}