arch/x86/oprofile/nmi_int.c - kernel/msm-5.4 - Gitiles

 /**
  * @file nmi_int.c
  *
  * @remark Copyright 2002 OProfile authors
  * @remark Read the file COPYING
  *
  * @author John Levon <levon@movementarian.org>
  */

 #include <linux/init.h>
 #include <linux/notifier.h>
 #include <linux/smp.h>
 #include <linux/oprofile.h>
 #include <linux/sysdev.h>
 #include <linux/slab.h>
 #include <linux/moduleparam.h>
 #include <linux/kdebug.h>
 #include <asm/nmi.h>
 #include <asm/msr.h>
 #include <asm/apic.h>

 #include "op_counter.h"
 #include "op_x86_model.h"

 static struct op_x86_model_spec const * model;
 static struct op_msrs cpu_msrs[NR_CPUS];
 static unsigned long saved_lvtpc[NR_CPUS];

 static int nmi_start(void);
 static void nmi_stop(void);

 /* 0 == registered but off, 1 == registered and on */
 static int nmi_enabled = 0;

 #ifdef CONFIG_PM

 static int nmi_suspend(struct sys_device *dev, pm_message_t state)
 {
 	if (nmi_enabled == 1)
 		nmi_stop();
 	return 0;
 }


 static int nmi_resume(struct sys_device *dev)
 {
 	if (nmi_enabled == 1)
 		nmi_start();
 	return 0;
 }


 static struct sysdev_class oprofile_sysclass = {
 	.name		= "oprofile",
 	.resume		= nmi_resume,
 	.suspend	= nmi_suspend,
 };


 static struct sys_device device_oprofile = {
 	.id	= 0,
 	.cls	= &oprofile_sysclass,
 };


 static int __init init_sysfs(void)
 {
 	int error;
 	if (!(error = sysdev_class_register(&oprofile_sysclass)))
 		error = sysdev_register(&device_oprofile);
 	return error;
 }


 static void exit_sysfs(void)
 {
 	sysdev_unregister(&device_oprofile);
 	sysdev_class_unregister(&oprofile_sysclass);
 }

 #else
 #define init_sysfs() do { } while (0)
 #define exit_sysfs() do { } while (0)
 #endif /* CONFIG_PM */

 static int profile_exceptions_notify(struct notifier_block *self,
 				     unsigned long val, void *data)
 {
 	struct die_args *args = (struct die_args *)data;
 	int ret = NOTIFY_DONE;
 	int cpu = smp_processor_id();

 	switch(val) {
 	case DIE_NMI:
 		if (model->check_ctrs(args->regs, &cpu_msrs[cpu]))
 			ret = NOTIFY_STOP;
 		break;
 	default:
 		break;
 	}
 	return ret;
 }

 static void nmi_cpu_save_registers(struct op_msrs * msrs)
 {
 	unsigned int const nr_ctrs = model->num_counters;
 	unsigned int const nr_ctrls = model->num_controls;
 	struct op_msr * counters = msrs->counters;
 	struct op_msr * controls = msrs->controls;
 	unsigned int i;

 	for (i = 0; i < nr_ctrs; ++i) {
 		if (counters[i].addr){
 			rdmsr(counters[i].addr,
 				counters[i].saved.low,
 				counters[i].saved.high);
 		}
 	}

 	for (i = 0; i < nr_ctrls; ++i) {
 		if (controls[i].addr){
 			rdmsr(controls[i].addr,
 				controls[i].saved.low,
 				controls[i].saved.high);
 		}
 	}
 }


 static void nmi_save_registers(void * dummy)
 {
 	int cpu = smp_processor_id();
 	struct op_msrs * msrs = &cpu_msrs[cpu];
 	nmi_cpu_save_registers(msrs);
 }


 static void free_msrs(void)
 {
 	int i;
 	for_each_possible_cpu(i) {
 		kfree(cpu_msrs[i].counters);
 		cpu_msrs[i].counters = NULL;
 		kfree(cpu_msrs[i].controls);
 		cpu_msrs[i].controls = NULL;
 	}
 }


 static int allocate_msrs(void)
 {
 	int success = 1;
 	size_t controls_size = sizeof(struct op_msr) * model->num_controls;
 	size_t counters_size = sizeof(struct op_msr) * model->num_counters;

 	int i;
 	for_each_possible_cpu(i) {
 		cpu_msrs[i].counters = kmalloc(counters_size, GFP_KERNEL);
 		if (!cpu_msrs[i].counters) {
 			success = 0;
 			break;
 		}
 		cpu_msrs[i].controls = kmalloc(controls_size, GFP_KERNEL);
 		if (!cpu_msrs[i].controls) {
 			success = 0;
 			break;
 		}
 	}

 	if (!success)
 		free_msrs();

 	return success;
 }


 static void nmi_cpu_setup(void * dummy)
 {
 	int cpu = smp_processor_id();
 	struct op_msrs * msrs = &cpu_msrs[cpu];
 	spin_lock(&oprofilefs_lock);
 	model->setup_ctrs(msrs);
 	spin_unlock(&oprofilefs_lock);
 	saved_lvtpc[cpu] = apic_read(APIC_LVTPC);
 	apic_write(APIC_LVTPC, APIC_DM_NMI);
 }

 static struct notifier_block profile_exceptions_nb = {
 	.notifier_call = profile_exceptions_notify,
 	.next = NULL,
 	.priority = 0
 };

 static int nmi_setup(void)
 {
 	int err=0;
 	int cpu;

 	if (!allocate_msrs())
 		return -ENOMEM;

 	if ((err = register_die_notifier(&profile_exceptions_nb))){
 		free_msrs();
 		return err;
 	}

 	/* We need to serialize save and setup for HT because the subset
 	 * of msrs are distinct for save and setup operations
 	 */

 	/* Assume saved/restored counters are the same on all CPUs */
 	model->fill_in_addresses(&cpu_msrs[0]);
 	for_each_possible_cpu (cpu) {
 		if (cpu != 0) {
 			memcpy(cpu_msrs[cpu].counters, cpu_msrs[0].counters,
 				sizeof(struct op_msr) * model->num_counters);

 			memcpy(cpu_msrs[cpu].controls, cpu_msrs[0].controls,
 				sizeof(struct op_msr) * model->num_controls);
 		}

 	}
 	on_each_cpu(nmi_save_registers, NULL, 0, 1);
 	on_each_cpu(nmi_cpu_setup, NULL, 0, 1);
 	nmi_enabled = 1;
 	return 0;
 }


 static void nmi_restore_registers(struct op_msrs * msrs)
 {
 	unsigned int const nr_ctrs = model->num_counters;
 	unsigned int const nr_ctrls = model->num_controls;
 	struct op_msr * counters = msrs->counters;
 	struct op_msr * controls = msrs->controls;
 	unsigned int i;

 	for (i = 0; i < nr_ctrls; ++i) {
 		if (controls[i].addr){
 			wrmsr(controls[i].addr,
 				controls[i].saved.low,
 				controls[i].saved.high);
 		}
 	}

 	for (i = 0; i < nr_ctrs; ++i) {
 		if (counters[i].addr){
 			wrmsr(counters[i].addr,
 				counters[i].saved.low,
 				counters[i].saved.high);
 		}
 	}
 }


 static void nmi_cpu_shutdown(void * dummy)
 {
 	unsigned int v;
 	int cpu = smp_processor_id();
 	struct op_msrs * msrs = &cpu_msrs[cpu];

 	/* restoring APIC_LVTPC can trigger an apic error because the delivery
 	 * mode and vector nr combination can be illegal. That's by design: on
 	 * power on apic lvt contain a zero vector nr which are legal only for
 	 * NMI delivery mode. So inhibit apic err before restoring lvtpc
 	 */
 	v = apic_read(APIC_LVTERR);
 	apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
 	apic_write(APIC_LVTPC, saved_lvtpc[cpu]);
 	apic_write(APIC_LVTERR, v);
 	nmi_restore_registers(msrs);
 }


 static void nmi_shutdown(void)
 {
 	nmi_enabled = 0;
 	on_each_cpu(nmi_cpu_shutdown, NULL, 0, 1);
 	unregister_die_notifier(&profile_exceptions_nb);
 	model->shutdown(cpu_msrs);
 	free_msrs();
 }


 static void nmi_cpu_start(void * dummy)
 {
 	struct op_msrs const * msrs = &cpu_msrs[smp_processor_id()];
 	model->start(msrs);
 }


 static int nmi_start(void)
 {
 	on_each_cpu(nmi_cpu_start, NULL, 0, 1);
 	return 0;
 }


 static void nmi_cpu_stop(void * dummy)
 {
 	struct op_msrs const * msrs = &cpu_msrs[smp_processor_id()];
 	model->stop(msrs);
 }


 static void nmi_stop(void)
 {
 	on_each_cpu(nmi_cpu_stop, NULL, 0, 1);
 }


 struct op_counter_config counter_config[OP_MAX_COUNTER];

 static int nmi_create_files(struct super_block * sb, struct dentry * root)
 {
 	unsigned int i;

 	for (i = 0; i < model->num_counters; ++i) {
 		struct dentry * dir;
 		char buf[4];

  		/* quick little hack to _not_ expose a counter if it is not
 		 * available for use.  This should protect userspace app.
 		 * NOTE:  assumes 1:1 mapping here (that counters are organized
 		 *        sequentially in their struct assignment).
 		 */
 		if (unlikely(!avail_to_resrv_perfctr_nmi_bit(i)))
 			continue;

 		snprintf(buf,  sizeof(buf), "%d", i);
 		dir = oprofilefs_mkdir(sb, root, buf);
 		oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
 		oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
 		oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
 		oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
 		oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
 		oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
 	}

 	return 0;
 }

 static int p4force;
 module_param(p4force, int, 0);

 static int __init p4_init(char ** cpu_type)
 {
 	__u8 cpu_model = boot_cpu_data.x86_model;

 	if (!p4force && (cpu_model > 6 || cpu_model == 5))
 		return 0;

 #ifndef CONFIG_SMP
 	*cpu_type = "i386/p4";
 	model = &op_p4_spec;
 	return 1;
 #else
 	switch (smp_num_siblings) {
 		case 1:
 			*cpu_type = "i386/p4";
 			model = &op_p4_spec;
 			return 1;

 		case 2:
 			*cpu_type = "i386/p4-ht";
 			model = &op_p4_ht2_spec;
 			return 1;
 	}
 #endif

 	printk(KERN_INFO "oprofile: P4 HyperThreading detected with > 2 threads\n");
 	printk(KERN_INFO "oprofile: Reverting to timer mode.\n");
 	return 0;
 }


 static int __init ppro_init(char ** cpu_type)
 {
 	__u8 cpu_model = boot_cpu_data.x86_model;

 	if (cpu_model == 14)
 		*cpu_type = "i386/core";
 	else if (cpu_model == 15 || cpu_model == 23)
 		*cpu_type = "i386/core_2";
 	else if (cpu_model > 0xd)
 		return 0;
 	else if (cpu_model == 9) {
 		*cpu_type = "i386/p6_mobile";
 	} else if (cpu_model > 5) {
 		*cpu_type = "i386/piii";
 	} else if (cpu_model > 2) {
 		*cpu_type = "i386/pii";
 	} else {
 		*cpu_type = "i386/ppro";
 	}

 	model = &op_ppro_spec;
 	return 1;
 }

 /* in order to get sysfs right */
 static int using_nmi;

 int __init op_nmi_init(struct oprofile_operations *ops)
 {
 	__u8 vendor = boot_cpu_data.x86_vendor;
 	__u8 family = boot_cpu_data.x86;
 	char *cpu_type;

 	if (!cpu_has_apic)
 		return -ENODEV;

 	switch (vendor) {
 		case X86_VENDOR_AMD:
 			/* Needs to be at least an Athlon (or hammer in 32bit mode) */

 			switch (family) {
 			default:
 				return -ENODEV;
 			case 6:
 				model = &op_athlon_spec;
 				cpu_type = "i386/athlon";
 				break;
 			case 0xf:
 				model = &op_athlon_spec;
 				/* Actually it could be i386/hammer too, but give
 				   user space an consistent name. */
 				cpu_type = "x86-64/hammer";
 				break;
 			case 0x10:
 				model = &op_athlon_spec;
 				cpu_type = "x86-64/family10";
 				break;
 			}
 			break;

 		case X86_VENDOR_INTEL:
 			switch (family) {
 				/* Pentium IV */
 				case 0xf:
 					if (!p4_init(&cpu_type))
 						return -ENODEV;
 					break;

 				/* A P6-class processor */
 				case 6:
 					if (!ppro_init(&cpu_type))
 						return -ENODEV;
 					break;

 				default:
 					return -ENODEV;
 			}
 			break;

 		default:
 			return -ENODEV;
 	}

 	init_sysfs();
 	using_nmi = 1;
 	ops->create_files = nmi_create_files;
 	ops->setup = nmi_setup;
 	ops->shutdown = nmi_shutdown;
 	ops->start = nmi_start;
 	ops->stop = nmi_stop;
 	ops->cpu_type = cpu_type;
 	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
 	return 0;
 }


 void op_nmi_exit(void)
 {
 	if (using_nmi)
 		exit_sysfs();
 }
	/**
	* @file nmi_int.c
	*
	* @remark Copyright 2002 OProfile authors
	* @remark Read the file COPYING
	*
	* @author John Levon <levon@movementarian.org>
	*/

	#include <linux/init.h>
	#include <linux/notifier.h>
	#include <linux/smp.h>
	#include <linux/oprofile.h>
	#include <linux/sysdev.h>
	#include <linux/slab.h>
	#include <linux/moduleparam.h>
	#include <linux/kdebug.h>
	#include <asm/nmi.h>
	#include <asm/msr.h>
	#include <asm/apic.h>

	#include "op_counter.h"
	#include "op_x86_model.h"

	static struct op_x86_model_spec const * model;
	static struct op_msrs cpu_msrs[NR_CPUS];
	static unsigned long saved_lvtpc[NR_CPUS];

	static int nmi_start(void);
	static void nmi_stop(void);

	/* 0 == registered but off, 1 == registered and on */
	static int nmi_enabled = 0;

	#ifdef CONFIG_PM

	static int nmi_suspend(struct sys_device *dev, pm_message_t state)
	{
	if (nmi_enabled == 1)
	nmi_stop();
	return 0;
	}


	static int nmi_resume(struct sys_device *dev)
	{
	if (nmi_enabled == 1)
	nmi_start();
	return 0;
	}


	static struct sysdev_class oprofile_sysclass = {
	.name = "oprofile",
	.resume = nmi_resume,
	.suspend = nmi_suspend,
	};


	static struct sys_device device_oprofile = {
	.id = 0,
	.cls = &oprofile_sysclass,
	};


	static int __init init_sysfs(void)
	{
	int error;
	if (!(error = sysdev_class_register(&oprofile_sysclass)))
	error = sysdev_register(&device_oprofile);
	return error;
	}


	static void exit_sysfs(void)
	{
	sysdev_unregister(&device_oprofile);
	sysdev_class_unregister(&oprofile_sysclass);
	}

	#else
	#define init_sysfs() do { } while (0)
	#define exit_sysfs() do { } while (0)
	#endif /* CONFIG_PM */

	static int profile_exceptions_notify(struct notifier_block *self,
	unsigned long val, void *data)
	{
	struct die_args args = (struct die_args )data;
	int ret = NOTIFY_DONE;
	int cpu = smp_processor_id();

	switch(val) {
	case DIE_NMI:
	if (model->check_ctrs(args->regs, &cpu_msrs[cpu]))
	ret = NOTIFY_STOP;
	break;
	default:
	break;
	}
	return ret;
	}

	static void nmi_cpu_save_registers(struct op_msrs * msrs)
	{
	unsigned int const nr_ctrs = model->num_counters;
	unsigned int const nr_ctrls = model->num_controls;
	struct op_msr * counters = msrs->counters;
	struct op_msr * controls = msrs->controls;
	unsigned int i;

	for (i = 0; i < nr_ctrs; ++i) {
	if (counters[i].addr){
	rdmsr(counters[i].addr,
	counters[i].saved.low,
	counters[i].saved.high);
	}
	}

	for (i = 0; i < nr_ctrls; ++i) {
	if (controls[i].addr){
	rdmsr(controls[i].addr,
	controls[i].saved.low,
	controls[i].saved.high);
	}
	}
	}


	static void nmi_save_registers(void * dummy)
	{
	int cpu = smp_processor_id();
	struct op_msrs * msrs = &cpu_msrs[cpu];
	nmi_cpu_save_registers(msrs);
	}


	static void free_msrs(void)
	{
	int i;
	for_each_possible_cpu(i) {
	kfree(cpu_msrs[i].counters);
	cpu_msrs[i].counters = NULL;
	kfree(cpu_msrs[i].controls);
	cpu_msrs[i].controls = NULL;
	}
	}


	static int allocate_msrs(void)
	{
	int success = 1;
	size_t controls_size = sizeof(struct op_msr) * model->num_controls;
	size_t counters_size = sizeof(struct op_msr) * model->num_counters;

	int i;
	for_each_possible_cpu(i) {
	cpu_msrs[i].counters = kmalloc(counters_size, GFP_KERNEL);
	if (!cpu_msrs[i].counters) {
	success = 0;
	break;
	}
	cpu_msrs[i].controls = kmalloc(controls_size, GFP_KERNEL);
	if (!cpu_msrs[i].controls) {
	success = 0;
	break;
	}
	}

	if (!success)
	free_msrs();

	return success;
	}


	static void nmi_cpu_setup(void * dummy)
	{
	int cpu = smp_processor_id();
	struct op_msrs * msrs = &cpu_msrs[cpu];
	spin_lock(&oprofilefs_lock);
	model->setup_ctrs(msrs);
	spin_unlock(&oprofilefs_lock);
	saved_lvtpc[cpu] = apic_read(APIC_LVTPC);
	apic_write(APIC_LVTPC, APIC_DM_NMI);
	}

	static struct notifier_block profile_exceptions_nb = {
	.notifier_call = profile_exceptions_notify,
	.next = NULL,
	.priority = 0
	};

	static int nmi_setup(void)
	{
	int err=0;
	int cpu;

	if (!allocate_msrs())
	return -ENOMEM;

	if ((err = register_die_notifier(&profile_exceptions_nb))){
	free_msrs();
	return err;
	}

	/* We need to serialize save and setup for HT because the subset
	* of msrs are distinct for save and setup operations
	*/

	/* Assume saved/restored counters are the same on all CPUs */
	model->fill_in_addresses(&cpu_msrs[0]);
	for_each_possible_cpu (cpu) {
	if (cpu != 0) {
	memcpy(cpu_msrs[cpu].counters, cpu_msrs[0].counters,
	sizeof(struct op_msr) * model->num_counters);

	memcpy(cpu_msrs[cpu].controls, cpu_msrs[0].controls,
	sizeof(struct op_msr) * model->num_controls);
	}

	}
	on_each_cpu(nmi_save_registers, NULL, 0, 1);
	on_each_cpu(nmi_cpu_setup, NULL, 0, 1);
	nmi_enabled = 1;
	return 0;
	}


	static void nmi_restore_registers(struct op_msrs * msrs)
	{
	unsigned int const nr_ctrs = model->num_counters;
	unsigned int const nr_ctrls = model->num_controls;
	struct op_msr * counters = msrs->counters;
	struct op_msr * controls = msrs->controls;
	unsigned int i;

	for (i = 0; i < nr_ctrls; ++i) {
	if (controls[i].addr){
	wrmsr(controls[i].addr,
	controls[i].saved.low,
	controls[i].saved.high);
	}
	}

	for (i = 0; i < nr_ctrs; ++i) {
	if (counters[i].addr){
	wrmsr(counters[i].addr,
	counters[i].saved.low,
	counters[i].saved.high);
	}
	}
	}


	static void nmi_cpu_shutdown(void * dummy)
	{
	unsigned int v;
	int cpu = smp_processor_id();
	struct op_msrs * msrs = &cpu_msrs[cpu];

	/* restoring APIC_LVTPC can trigger an apic error because the delivery
	* mode and vector nr combination can be illegal. That's by design: on
	* power on apic lvt contain a zero vector nr which are legal only for
	* NMI delivery mode. So inhibit apic err before restoring lvtpc
	*/
	v = apic_read(APIC_LVTERR);
	apic_write(APIC_LVTERR, v \| APIC_LVT_MASKED);
	apic_write(APIC_LVTPC, saved_lvtpc[cpu]);
	apic_write(APIC_LVTERR, v);
	nmi_restore_registers(msrs);
	}


	static void nmi_shutdown(void)
	{
	nmi_enabled = 0;
	on_each_cpu(nmi_cpu_shutdown, NULL, 0, 1);
	unregister_die_notifier(&profile_exceptions_nb);
	model->shutdown(cpu_msrs);
	free_msrs();
	}


	static void nmi_cpu_start(void * dummy)
	{
	struct op_msrs const * msrs = &cpu_msrs[smp_processor_id()];
	model->start(msrs);
	}


	static int nmi_start(void)
	{
	on_each_cpu(nmi_cpu_start, NULL, 0, 1);
	return 0;
	}


	static void nmi_cpu_stop(void * dummy)
	{
	struct op_msrs const * msrs = &cpu_msrs[smp_processor_id()];
	model->stop(msrs);
	}


	static void nmi_stop(void)
	{
	on_each_cpu(nmi_cpu_stop, NULL, 0, 1);
	}


	struct op_counter_config counter_config[OP_MAX_COUNTER];

	static int nmi_create_files(struct super_block * sb, struct dentry * root)
	{
	unsigned int i;

	for (i = 0; i < model->num_counters; ++i) {
	struct dentry * dir;
	char buf[4];

	/* quick little hack to _not_ expose a counter if it is not
	* available for use. This should protect userspace app.
	* NOTE: assumes 1:1 mapping here (that counters are organized
	* sequentially in their struct assignment).
	*/
	if (unlikely(!avail_to_resrv_perfctr_nmi_bit(i)))
	continue;

	snprintf(buf, sizeof(buf), "%d", i);
	dir = oprofilefs_mkdir(sb, root, buf);
	oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
	oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
	oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
	oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
	oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
	oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
	}

	return 0;
	}

	static int p4force;
	module_param(p4force, int, 0);

	static int __init p4_init(char ** cpu_type)
	{
	__u8 cpu_model = boot_cpu_data.x86_model;

	if (!p4force && (cpu_model > 6 \|\| cpu_model == 5))
	return 0;

	#ifndef CONFIG_SMP
	*cpu_type = "i386/p4";
	model = &op_p4_spec;
	return 1;
	#else
	switch (smp_num_siblings) {
	case 1:
	*cpu_type = "i386/p4";
	model = &op_p4_spec;
	return 1;

	case 2:
	*cpu_type = "i386/p4-ht";
	model = &op_p4_ht2_spec;
	return 1;
	}
	#endif

	printk(KERN_INFO "oprofile: P4 HyperThreading detected with > 2 threads\n");
	printk(KERN_INFO "oprofile: Reverting to timer mode.\n");
	return 0;
	}


	static int __init ppro_init(char ** cpu_type)
	{
	__u8 cpu_model = boot_cpu_data.x86_model;

	if (cpu_model == 14)
	*cpu_type = "i386/core";
	else if (cpu_model == 15 \|\| cpu_model == 23)
	*cpu_type = "i386/core_2";
	else if (cpu_model > 0xd)
	return 0;
	else if (cpu_model == 9) {
	*cpu_type = "i386/p6_mobile";
	} else if (cpu_model > 5) {
	*cpu_type = "i386/piii";
	} else if (cpu_model > 2) {
	*cpu_type = "i386/pii";
	} else {
	*cpu_type = "i386/ppro";
	}

	model = &op_ppro_spec;
	return 1;
	}

	/* in order to get sysfs right */
	static int using_nmi;

	int __init op_nmi_init(struct oprofile_operations *ops)
	{
	__u8 vendor = boot_cpu_data.x86_vendor;
	__u8 family = boot_cpu_data.x86;
	char *cpu_type;

	if (!cpu_has_apic)
	return -ENODEV;

	switch (vendor) {
	case X86_VENDOR_AMD:
	/* Needs to be at least an Athlon (or hammer in 32bit mode) */

	switch (family) {
	default:
	return -ENODEV;
	case 6:
	model = &op_athlon_spec;
	cpu_type = "i386/athlon";
	break;
	case 0xf:
	model = &op_athlon_spec;
	/* Actually it could be i386/hammer too, but give
	user space an consistent name. */
	cpu_type = "x86-64/hammer";
	break;
	case 0x10:
	model = &op_athlon_spec;
	cpu_type = "x86-64/family10";
	break;
	}
	break;

	case X86_VENDOR_INTEL:
	switch (family) {
	/* Pentium IV */
	case 0xf:
	if (!p4_init(&cpu_type))
	return -ENODEV;
	break;

	/* A P6-class processor */
	case 6:
	if (!ppro_init(&cpu_type))
	return -ENODEV;
	break;

	default:
	return -ENODEV;
	}
	break;

	default:
	return -ENODEV;
	}

	init_sysfs();
	using_nmi = 1;
	ops->create_files = nmi_create_files;
	ops->setup = nmi_setup;
	ops->shutdown = nmi_shutdown;
	ops->start = nmi_start;
	ops->stop = nmi_stop;
	ops->cpu_type = cpu_type;
	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
	return 0;
	}


	void op_nmi_exit(void)
	{
	if (using_nmi)
	exit_sysfs();
	}