arch/x86/oprofile/nmi_int.c - arm/linux-arm64-legacy - Git at Google

 /**
  * @file nmi_int.c
  *
  * @remark Copyright 2002-2008 OProfile authors
  * @remark Read the file COPYING
  *
  * @author John Levon <levon@movementarian.org>
  * @author Robert Richter <robert.richter@amd.com>
  */

 #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 <linux/cpu.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 DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
 static DEFINE_PER_CPU(unsigned long, saved_lvtpc);

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

 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, &per_cpu(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 = &per_cpu(cpu_msrs, cpu);
 	nmi_cpu_save_registers(msrs);
 }

 static void free_msrs(void)
 {
 	int i;
 	for_each_possible_cpu(i) {
 		kfree(per_cpu(cpu_msrs, i).counters);
 		per_cpu(cpu_msrs, i).counters = NULL;
 		kfree(per_cpu(cpu_msrs, i).controls);
 		per_cpu(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) {
 		per_cpu(cpu_msrs, i).counters = kmalloc(counters_size,
 								GFP_KERNEL);
 		if (!per_cpu(cpu_msrs, i).counters) {
 			success = 0;
 			break;
 		}
 		per_cpu(cpu_msrs, i).controls = kmalloc(controls_size,
 								GFP_KERNEL);
 		if (!per_cpu(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 = &per_cpu(cpu_msrs, cpu);
 	spin_lock(&oprofilefs_lock);
 	model->setup_ctrs(msrs);
 	spin_unlock(&oprofilefs_lock);
 	per_cpu(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;

 	err = register_die_notifier(&profile_exceptions_nb);
 	if (err) {
 		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(&per_cpu(cpu_msrs, 0));
 	for_each_possible_cpu(cpu) {
 		if (cpu != 0) {
 			memcpy(per_cpu(cpu_msrs, cpu).counters,
 				per_cpu(cpu_msrs, 0).counters,
 				sizeof(struct op_msr) * model->num_counters);

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

 	}
 	on_each_cpu(nmi_save_registers, NULL, 1);
 	on_each_cpu(nmi_cpu_setup, NULL, 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 = &__get_cpu_var(cpu_msrs);

 	/* 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, per_cpu(saved_lvtpc, cpu));
 	apic_write(APIC_LVTERR, v);
 	nmi_restore_registers(msrs);
 }

 static void nmi_shutdown(void)
 {
 	struct op_msrs *msrs;

 	nmi_enabled = 0;
 	on_each_cpu(nmi_cpu_shutdown, NULL, 1);
 	unregister_die_notifier(&profile_exceptions_nb);
 	msrs = &get_cpu_var(cpu_msrs);
 	model->shutdown(msrs);
 	free_msrs();
 	put_cpu_var(cpu_msrs);
 }

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

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

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

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

 #ifdef CONFIG_SMP
 static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
 				 void *data)
 {
 	int cpu = (unsigned long)data;
 	switch (action) {
 	case CPU_DOWN_FAILED:
 	case CPU_ONLINE:
 		smp_call_function_single(cpu, nmi_cpu_start, NULL, 0);
 		break;
 	case CPU_DOWN_PREPARE:
 		smp_call_function_single(cpu, nmi_cpu_stop, NULL, 1);
 		break;
 	}
 	return NOTIFY_DONE;
 }

 static struct notifier_block oprofile_cpu_nb = {
 	.notifier_call = oprofile_cpu_notifier
 };
 #endif

 #ifdef CONFIG_PM

 static int nmi_suspend(struct sys_device *dev, pm_message_t state)
 {
 	/* Only one CPU left, just stop that one */
 	if (nmi_enabled == 1)
 		nmi_cpu_stop(NULL);
 	return 0;
 }

 static int nmi_resume(struct sys_device *dev)
 {
 	if (nmi_enabled == 1)
 		nmi_cpu_start(NULL);
 	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;

 	error = sysdev_class_register(&oprofile_sysclass);
 	if (!error)
 		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 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;

 	switch (cpu_model) {
 	case 0 ... 2:
 		*cpu_type = "i386/ppro";
 		break;
 	case 3 ... 5:
 		*cpu_type = "i386/pii";
 		break;
 	case 6 ... 8:
 	case 10 ... 11:
 		*cpu_type = "i386/piii";
 		break;
 	case 9:
 	case 13:
 		*cpu_type = "i386/p6_mobile";
 		break;
 	case 14:
 		*cpu_type = "i386/core";
 		break;
 	case 15: case 23:
 		*cpu_type = "i386/core_2";
 		break;
 	default:
 		/* Unknown */
 		return 0;
 	}

 	model = &op_ppro_spec;
 	return 1;
 }

 static int __init arch_perfmon_init(char **cpu_type)
 {
 	if (!cpu_has_arch_perfmon)
 		return 0;
 	*cpu_type = "i386/arch_perfmon";
 	model = &op_arch_perfmon_spec;
 	arch_perfmon_setup_counters();
 	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 = NULL;
 	int ret = 0;

 	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_amd_spec;
 			cpu_type = "i386/athlon";
 			break;
 		case 0xf:
 			model = &op_amd_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_amd_spec;
 			cpu_type = "x86-64/family10";
 			break;
 		case 0x11:
 			model = &op_amd_spec;
 			cpu_type = "x86-64/family11h";
 			break;
 		}
 		break;

 	case X86_VENDOR_INTEL:
 		switch (family) {
 			/* Pentium IV */
 		case 0xf:
 			p4_init(&cpu_type);
 			break;

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

 		default:
 			break;
 		}

 		if (!cpu_type && !arch_perfmon_init(&cpu_type))
 			return -ENODEV;
 		break;

 	default:
 		return -ENODEV;
 	}

 #ifdef CONFIG_SMP
 	register_cpu_notifier(&oprofile_cpu_nb);
 #endif
 	/* default values, can be overwritten by model */
 	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;

 	if (model->init)
 		ret = model->init(ops);
 	if (ret)
 		return ret;

 	init_sysfs();
 	using_nmi = 1;
 	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
 	return 0;
 }

 void op_nmi_exit(void)
 {
 	if (using_nmi) {
 		exit_sysfs();
 #ifdef CONFIG_SMP
 		unregister_cpu_notifier(&oprofile_cpu_nb);
 #endif
 	}
 	if (model->exit)
 		model->exit();
 }
	/**
	* @file nmi_int.c
	*
	* @remark Copyright 2002-2008 OProfile authors
	* @remark Read the file COPYING
	*
	* @author John Levon <levon@movementarian.org>
	* @author Robert Richter <robert.richter@amd.com>
	*/

	#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 <linux/cpu.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 DEFINE_PER_CPU(struct op_msrs, cpu_msrs);
	static DEFINE_PER_CPU(unsigned long, saved_lvtpc);

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

	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, &per_cpu(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 = &per_cpu(cpu_msrs, cpu);
	nmi_cpu_save_registers(msrs);
	}

	static void free_msrs(void)
	{
	int i;
	for_each_possible_cpu(i) {
	kfree(per_cpu(cpu_msrs, i).counters);
	per_cpu(cpu_msrs, i).counters = NULL;
	kfree(per_cpu(cpu_msrs, i).controls);
	per_cpu(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) {
	per_cpu(cpu_msrs, i).counters = kmalloc(counters_size,
	GFP_KERNEL);
	if (!per_cpu(cpu_msrs, i).counters) {
	success = 0;
	break;
	}
	per_cpu(cpu_msrs, i).controls = kmalloc(controls_size,
	GFP_KERNEL);
	if (!per_cpu(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 = &per_cpu(cpu_msrs, cpu);
	spin_lock(&oprofilefs_lock);
	model->setup_ctrs(msrs);
	spin_unlock(&oprofilefs_lock);
	per_cpu(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;

	err = register_die_notifier(&profile_exceptions_nb);
	if (err) {
	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(&per_cpu(cpu_msrs, 0));
	for_each_possible_cpu(cpu) {
	if (cpu != 0) {
	memcpy(per_cpu(cpu_msrs, cpu).counters,
	per_cpu(cpu_msrs, 0).counters,
	sizeof(struct op_msr) * model->num_counters);

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

	}
	on_each_cpu(nmi_save_registers, NULL, 1);
	on_each_cpu(nmi_cpu_setup, NULL, 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 = &__get_cpu_var(cpu_msrs);

	/* 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, per_cpu(saved_lvtpc, cpu));
	apic_write(APIC_LVTERR, v);
	nmi_restore_registers(msrs);
	}

	static void nmi_shutdown(void)
	{
	struct op_msrs *msrs;

	nmi_enabled = 0;
	on_each_cpu(nmi_cpu_shutdown, NULL, 1);
	unregister_die_notifier(&profile_exceptions_nb);
	msrs = &get_cpu_var(cpu_msrs);
	model->shutdown(msrs);
	free_msrs();
	put_cpu_var(cpu_msrs);
	}

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

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

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

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

	#ifdef CONFIG_SMP
	static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
	void *data)
	{
	int cpu = (unsigned long)data;
	switch (action) {
	case CPU_DOWN_FAILED:
	case CPU_ONLINE:
	smp_call_function_single(cpu, nmi_cpu_start, NULL, 0);
	break;
	case CPU_DOWN_PREPARE:
	smp_call_function_single(cpu, nmi_cpu_stop, NULL, 1);
	break;
	}
	return NOTIFY_DONE;
	}

	static struct notifier_block oprofile_cpu_nb = {
	.notifier_call = oprofile_cpu_notifier
	};
	#endif

	#ifdef CONFIG_PM

	static int nmi_suspend(struct sys_device *dev, pm_message_t state)
	{
	/* Only one CPU left, just stop that one */
	if (nmi_enabled == 1)
	nmi_cpu_stop(NULL);
	return 0;
	}

	static int nmi_resume(struct sys_device *dev)
	{
	if (nmi_enabled == 1)
	nmi_cpu_start(NULL);
	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;

	error = sysdev_class_register(&oprofile_sysclass);
	if (!error)
	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 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;

	switch (cpu_model) {
	case 0 ... 2:
	*cpu_type = "i386/ppro";
	break;
	case 3 ... 5:
	*cpu_type = "i386/pii";
	break;
	case 6 ... 8:
	case 10 ... 11:
	*cpu_type = "i386/piii";
	break;
	case 9:
	case 13:
	*cpu_type = "i386/p6_mobile";
	break;
	case 14:
	*cpu_type = "i386/core";
	break;
	case 15: case 23:
	*cpu_type = "i386/core_2";
	break;
	default:
	/* Unknown */
	return 0;
	}

	model = &op_ppro_spec;
	return 1;
	}

	static int __init arch_perfmon_init(char **cpu_type)
	{
	if (!cpu_has_arch_perfmon)
	return 0;
	*cpu_type = "i386/arch_perfmon";
	model = &op_arch_perfmon_spec;
	arch_perfmon_setup_counters();
	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 = NULL;
	int ret = 0;

	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_amd_spec;
	cpu_type = "i386/athlon";
	break;
	case 0xf:
	model = &op_amd_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_amd_spec;
	cpu_type = "x86-64/family10";
	break;
	case 0x11:
	model = &op_amd_spec;
	cpu_type = "x86-64/family11h";
	break;
	}
	break;

	case X86_VENDOR_INTEL:
	switch (family) {
	/* Pentium IV */
	case 0xf:
	p4_init(&cpu_type);
	break;

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

	default:
	break;
	}

	if (!cpu_type && !arch_perfmon_init(&cpu_type))
	return -ENODEV;
	break;

	default:
	return -ENODEV;
	}

	#ifdef CONFIG_SMP
	register_cpu_notifier(&oprofile_cpu_nb);
	#endif
	/* default values, can be overwritten by model */
	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;

	if (model->init)
	ret = model->init(ops);
	if (ret)
	return ret;

	init_sysfs();
	using_nmi = 1;
	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
	return 0;
	}

	void op_nmi_exit(void)
	{
	if (using_nmi) {
	exit_sysfs();
	#ifdef CONFIG_SMP
	unregister_cpu_notifier(&oprofile_cpu_nb);
	#endif
	}
	if (model->exit)
	model->exit();
	}