drivers/acpi/acpi_processor.c - kernel/msm-5.4 - Gitiles

 /*
  * acpi_processor.c - ACPI processor enumeration support
  *
  * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  * Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
  * Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
  * Copyright (C) 2013, Intel Corporation
  *                     Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published
  * by the Free Software Foundation.
  */

 #include <linux/acpi.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>

 #include <acpi/processor.h>

 #include <asm/cpu.h>

 #include "internal.h"

 #define _COMPONENT	ACPI_PROCESSOR_COMPONENT

 ACPI_MODULE_NAME("processor");

 DEFINE_PER_CPU(struct acpi_processor *, processors);
 EXPORT_PER_CPU_SYMBOL(processors);

 /* --------------------------------------------------------------------------
                                 Errata Handling
    -------------------------------------------------------------------------- */

 struct acpi_processor_errata errata __read_mostly;
 EXPORT_SYMBOL_GPL(errata);

 static int acpi_processor_errata_piix4(struct pci_dev *dev)
 {
 	u8 value1 = 0;
 	u8 value2 = 0;


 	if (!dev)
 		return -EINVAL;

 	/*
 	 * Note that 'dev' references the PIIX4 ACPI Controller.
 	 */

 	switch (dev->revision) {
 	case 0:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
 		break;
 	case 1:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
 		break;
 	case 2:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
 		break;
 	case 3:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
 		break;
 	default:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
 		break;
 	}

 	switch (dev->revision) {

 	case 0:		/* PIIX4 A-step */
 	case 1:		/* PIIX4 B-step */
 		/*
 		 * See specification changes #13 ("Manual Throttle Duty Cycle")
 		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
 		 * erratum #5 ("STPCLK# Deassertion Time") from the January
 		 * 2002 PIIX4 specification update.  Applies to only older
 		 * PIIX4 models.
 		 */
 		errata.piix4.throttle = 1;

 	case 2:		/* PIIX4E */
 	case 3:		/* PIIX4M */
 		/*
 		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
 		 * Livelock") from the January 2002 PIIX4 specification update.
 		 * Applies to all PIIX4 models.
 		 */

 		/*
 		 * BM-IDE
 		 * ------
 		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
 		 * Status register address.  We'll use this later to read
 		 * each IDE controller's DMA status to make sure we catch all
 		 * DMA activity.
 		 */
 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 				     PCI_DEVICE_ID_INTEL_82371AB,
 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
 		if (dev) {
 			errata.piix4.bmisx = pci_resource_start(dev, 4);
 			pci_dev_put(dev);
 		}

 		/*
 		 * Type-F DMA
 		 * ----------
 		 * Find the PIIX4 ISA Controller and read the Motherboard
 		 * DMA controller's status to see if Type-F (Fast) DMA mode
 		 * is enabled (bit 7) on either channel.  Note that we'll
 		 * disable C3 support if this is enabled, as some legacy
 		 * devices won't operate well if fast DMA is disabled.
 		 */
 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 				     PCI_DEVICE_ID_INTEL_82371AB_0,
 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
 		if (dev) {
 			pci_read_config_byte(dev, 0x76, &value1);
 			pci_read_config_byte(dev, 0x77, &value2);
 			if ((value1 & 0x80) || (value2 & 0x80))
 				errata.piix4.fdma = 1;
 			pci_dev_put(dev);
 		}

 		break;
 	}

 	if (errata.piix4.bmisx)
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Bus master activity detection (BM-IDE) erratum enabled\n"));
 	if (errata.piix4.fdma)
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Type-F DMA livelock erratum (C3 disabled)\n"));

 	return 0;
 }

 static int acpi_processor_errata(void)
 {
 	int result = 0;
 	struct pci_dev *dev = NULL;

 	/*
 	 * PIIX4
 	 */
 	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
 			     PCI_ANY_ID, NULL);
 	if (dev) {
 		result = acpi_processor_errata_piix4(dev);
 		pci_dev_put(dev);
 	}

 	return result;
 }

 /* --------------------------------------------------------------------------
                                 Initialization
    -------------------------------------------------------------------------- */

 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 static int acpi_processor_hotadd_init(struct acpi_processor *pr)
 {
 	unsigned long long sta;
 	acpi_status status;
 	int ret;

 	if (pr->apic_id == -1)
 		return -ENODEV;

 	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
 	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
 		return -ENODEV;

 	cpu_maps_update_begin();
 	cpu_hotplug_begin();

 	ret = acpi_map_lsapic(pr->handle, pr->apic_id, &pr->id);
 	if (ret)
 		goto out;

 	ret = arch_register_cpu(pr->id);
 	if (ret) {
 		acpi_unmap_lsapic(pr->id);
 		goto out;
 	}

 	/*
 	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
 	 * to delay cpu_idle/throttling initialization and do it when the CPU
 	 * gets online for the first time.
 	 */
 	pr_info("CPU%d has been hot-added\n", pr->id);
 	pr->flags.need_hotplug_init = 1;

 out:
 	cpu_hotplug_done();
 	cpu_maps_update_done();
 	return ret;
 }
 #else
 static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
 {
 	return -ENODEV;
 }
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */

 static int acpi_processor_get_info(struct acpi_device *device)
 {
 	union acpi_object object = { 0 };
 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
 	struct acpi_processor *pr = acpi_driver_data(device);
 	int apic_id, cpu_index, device_declaration = 0;
 	acpi_status status = AE_OK;
 	static int cpu0_initialized;
 	unsigned long long value;

 	acpi_processor_errata();

 	/*
 	 * Check to see if we have bus mastering arbitration control.  This
 	 * is required for proper C3 usage (to maintain cache coherency).
 	 */
 	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
 		pr->flags.bm_control = 1;
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Bus mastering arbitration control present\n"));
 	} else
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "No bus mastering arbitration control\n"));

 	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
 		/* Declared with "Processor" statement; match ProcessorID */
 		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
 		if (ACPI_FAILURE(status)) {
 			dev_err(&device->dev,
 				"Failed to evaluate processor object (0x%x)\n",
 				status);
 			return -ENODEV;
 		}

 		pr->acpi_id = object.processor.proc_id;
 	} else {
 		/*
 		 * Declared with "Device" statement; match _UID.
 		 * Note that we don't handle string _UIDs yet.
 		 */
 		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
 						NULL, &value);
 		if (ACPI_FAILURE(status)) {
 			dev_err(&device->dev,
 				"Failed to evaluate processor _UID (0x%x)\n",
 				status);
 			return -ENODEV;
 		}
 		device_declaration = 1;
 		pr->acpi_id = value;
 	}

 	apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id);
 	if (apic_id < 0)
 		acpi_handle_debug(pr->handle, "failed to get CPU APIC ID.\n");
 	pr->apic_id = apic_id;

 	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
 	if (!cpu0_initialized) {
 		cpu0_initialized = 1;
 		/* Handle UP system running SMP kernel, with no LAPIC in MADT */
 		if ((cpu_index == -1) && (num_online_cpus() == 1))
 			cpu_index = 0;
 	}
 	pr->id = cpu_index;

 	/*
 	 *  Extra Processor objects may be enumerated on MP systems with
 	 *  less than the max # of CPUs. They should be ignored _iff
 	 *  they are physically not present.
 	 */
 	if (pr->id == -1) {
 		int ret = acpi_processor_hotadd_init(pr);
 		if (ret)
 			return ret;
 	}

 	/*
 	 * On some boxes several processors use the same processor bus id.
 	 * But they are located in different scope. For example:
 	 * \_SB.SCK0.CPU0
 	 * \_SB.SCK1.CPU0
 	 * Rename the processor device bus id. And the new bus id will be
 	 * generated as the following format:
 	 * CPU+CPU ID.
 	 */
 	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
 			  pr->acpi_id));

 	if (!object.processor.pblk_address)
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
 	else if (object.processor.pblk_length != 6)
 		dev_err(&device->dev, "Invalid PBLK length [%d]\n",
 			    object.processor.pblk_length);
 	else {
 		pr->throttling.address = object.processor.pblk_address;
 		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
 		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;

 		pr->pblk = object.processor.pblk_address;

 		/*
 		 * We don't care about error returns - we just try to mark
 		 * these reserved so that nobody else is confused into thinking
 		 * that this region might be unused..
 		 *
 		 * (In particular, allocating the IO range for Cardbus)
 		 */
 		request_region(pr->throttling.address, 6, "ACPI CPU throttle");
 	}

 	/*
 	 * If ACPI describes a slot number for this CPU, we can use it to
 	 * ensure we get the right value in the "physical id" field
 	 * of /proc/cpuinfo
 	 */
 	status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
 	if (ACPI_SUCCESS(status))
 		arch_fix_phys_package_id(pr->id, value);

 	return 0;
 }

 /*
  * Do not put anything in here which needs the core to be online.
  * For example MSR access or setting up things which check for cpuinfo_x86
  * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
  * Such things have to be put in and set up by the processor driver's .probe().
  */
 static DEFINE_PER_CPU(void *, processor_device_array);

 static int acpi_processor_add(struct acpi_device *device,
 					const struct acpi_device_id *id)
 {
 	struct acpi_processor *pr;
 	struct device *dev;
 	int result = 0;

 	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
 	if (!pr)
 		return -ENOMEM;

 	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
 		result = -ENOMEM;
 		goto err_free_pr;
 	}

 	pr->handle = device->handle;
 	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
 	device->driver_data = pr;

 	result = acpi_processor_get_info(device);
 	if (result) /* Processor is not physically present or unavailable */
 		return 0;

 #ifdef CONFIG_SMP
 	if (pr->id >= setup_max_cpus && pr->id != 0)
 		return 0;
 #endif

 	BUG_ON(pr->id >= nr_cpu_ids);

 	/*
 	 * Buggy BIOS check.
 	 * ACPI id of processors can be reported wrongly by the BIOS.
 	 * Don't trust it blindly
 	 */
 	if (per_cpu(processor_device_array, pr->id) != NULL &&
 	    per_cpu(processor_device_array, pr->id) != device) {
 		dev_warn(&device->dev,
 			"BIOS reported wrong ACPI id %d for the processor\n",
 			pr->id);
 		/* Give up, but do not abort the namespace scan. */
 		goto err;
 	}
 	/*
 	 * processor_device_array is not cleared on errors to allow buggy BIOS
 	 * checks.
 	 */
 	per_cpu(processor_device_array, pr->id) = device;
 	per_cpu(processors, pr->id) = pr;

 	dev = get_cpu_device(pr->id);
 	if (!dev) {
 		result = -ENODEV;
 		goto err;
 	}

 	result = acpi_bind_one(dev, device);
 	if (result)
 		goto err;

 	pr->dev = dev;
 	dev->offline = pr->flags.need_hotplug_init;

 	/* Trigger the processor driver's .probe() if present. */
 	if (device_attach(dev) >= 0)
 		return 1;

 	dev_err(dev, "Processor driver could not be attached\n");
 	acpi_unbind_one(dev);

  err:
 	free_cpumask_var(pr->throttling.shared_cpu_map);
 	device->driver_data = NULL;
 	per_cpu(processors, pr->id) = NULL;
  err_free_pr:
 	kfree(pr);
 	return result;
 }

 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 /* --------------------------------------------------------------------------
                                     Removal
    -------------------------------------------------------------------------- */

 static void acpi_processor_remove(struct acpi_device *device)
 {
 	struct acpi_processor *pr;

 	if (!device || !acpi_driver_data(device))
 		return;

 	pr = acpi_driver_data(device);
 	if (pr->id >= nr_cpu_ids)
 		goto out;

 	/*
 	 * The only reason why we ever get here is CPU hot-removal.  The CPU is
 	 * already offline and the ACPI device removal locking prevents it from
 	 * being put back online at this point.
 	 *
 	 * Unbind the driver from the processor device and detach it from the
 	 * ACPI companion object.
 	 */
 	device_release_driver(pr->dev);
 	acpi_unbind_one(pr->dev);

 	/* Clean up. */
 	per_cpu(processor_device_array, pr->id) = NULL;
 	per_cpu(processors, pr->id) = NULL;

 	cpu_maps_update_begin();
 	cpu_hotplug_begin();

 	/* Remove the CPU. */
 	arch_unregister_cpu(pr->id);
 	acpi_unmap_lsapic(pr->id);

 	cpu_hotplug_done();
 	cpu_maps_update_done();

 	try_offline_node(cpu_to_node(pr->id));

  out:
 	free_cpumask_var(pr->throttling.shared_cpu_map);
 	kfree(pr);
 }
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */

 /*
  * The following ACPI IDs are known to be suitable for representing as
  * processor devices.
  */
 static const struct acpi_device_id processor_device_ids[] = {

 	{ ACPI_PROCESSOR_OBJECT_HID, },
 	{ ACPI_PROCESSOR_DEVICE_HID, },

 	{ }
 };

 static struct acpi_scan_handler __refdata processor_handler = {
 	.ids = processor_device_ids,
 	.attach = acpi_processor_add,
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 	.detach = acpi_processor_remove,
 #endif
 	.hotplug = {
 		.enabled = true,
 	},
 };

 void __init acpi_processor_init(void)
 {
 	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
 }
	/*
	* acpi_processor.c - ACPI processor enumeration support
	*
	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
	* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
	* Copyright (C) 2013, Intel Corporation
	* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published
	* by the Free Software Foundation.
	*/

	#include <linux/acpi.h>
	#include <linux/device.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/pci.h>

	#include <acpi/processor.h>

	#include <asm/cpu.h>

	#include "internal.h"

	#define _COMPONENT ACPI_PROCESSOR_COMPONENT

	ACPI_MODULE_NAME("processor");

	DEFINE_PER_CPU(struct acpi_processor *, processors);
	EXPORT_PER_CPU_SYMBOL(processors);

	/* --------------------------------------------------------------------------
	Errata Handling
	-------------------------------------------------------------------------- */

	struct acpi_processor_errata errata __read_mostly;
	EXPORT_SYMBOL_GPL(errata);

	static int acpi_processor_errata_piix4(struct pci_dev *dev)
	{
	u8 value1 = 0;
	u8 value2 = 0;


	if (!dev)
	return -EINVAL;

	/*
	* Note that 'dev' references the PIIX4 ACPI Controller.
	*/

	switch (dev->revision) {
	case 0:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
	break;
	case 1:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
	break;
	case 2:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
	break;
	case 3:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
	break;
	default:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
	break;
	}

	switch (dev->revision) {

	case 0: /* PIIX4 A-step */
	case 1: /* PIIX4 B-step */
	/*
	* See specification changes #13 ("Manual Throttle Duty Cycle")
	* and #14 ("Enabling and Disabling Manual Throttle"), plus
	* erratum #5 ("STPCLK# Deassertion Time") from the January
	* 2002 PIIX4 specification update. Applies to only older
	* PIIX4 models.
	*/
	errata.piix4.throttle = 1;

	case 2: /* PIIX4E */
	case 3: /* PIIX4M */
	/*
	* See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
	* Livelock") from the January 2002 PIIX4 specification update.
	* Applies to all PIIX4 models.
	*/

	/*
	* BM-IDE
	* ------
	* Find the PIIX4 IDE Controller and get the Bus Master IDE
	* Status register address. We'll use this later to read
	* each IDE controller's DMA status to make sure we catch all
	* DMA activity.
	*/
	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
	PCI_DEVICE_ID_INTEL_82371AB,
	PCI_ANY_ID, PCI_ANY_ID, NULL);
	if (dev) {
	errata.piix4.bmisx = pci_resource_start(dev, 4);
	pci_dev_put(dev);
	}

	/*
	* Type-F DMA
	* ----------
	* Find the PIIX4 ISA Controller and read the Motherboard
	* DMA controller's status to see if Type-F (Fast) DMA mode
	* is enabled (bit 7) on either channel. Note that we'll
	* disable C3 support if this is enabled, as some legacy
	* devices won't operate well if fast DMA is disabled.
	*/
	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
	PCI_DEVICE_ID_INTEL_82371AB_0,
	PCI_ANY_ID, PCI_ANY_ID, NULL);
	if (dev) {
	pci_read_config_byte(dev, 0x76, &value1);
	pci_read_config_byte(dev, 0x77, &value2);
	if ((value1 & 0x80) \|\| (value2 & 0x80))
	errata.piix4.fdma = 1;
	pci_dev_put(dev);
	}

	break;
	}

	if (errata.piix4.bmisx)
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Bus master activity detection (BM-IDE) erratum enabled\n"));
	if (errata.piix4.fdma)
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Type-F DMA livelock erratum (C3 disabled)\n"));

	return 0;
	}

	static int acpi_processor_errata(void)
	{
	int result = 0;
	struct pci_dev *dev = NULL;

	/*
	* PIIX4
	*/
	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
	PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
	PCI_ANY_ID, NULL);
	if (dev) {
	result = acpi_processor_errata_piix4(dev);
	pci_dev_put(dev);
	}

	return result;
	}

	/* --------------------------------------------------------------------------
	Initialization
	-------------------------------------------------------------------------- */

	#ifdef CONFIG_ACPI_HOTPLUG_CPU
	static int acpi_processor_hotadd_init(struct acpi_processor *pr)
	{
	unsigned long long sta;
	acpi_status status;
	int ret;

	if (pr->apic_id == -1)
	return -ENODEV;

	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
	if (ACPI_FAILURE(status) \|\| !(sta & ACPI_STA_DEVICE_PRESENT))
	return -ENODEV;

	cpu_maps_update_begin();
	cpu_hotplug_begin();

	ret = acpi_map_lsapic(pr->handle, pr->apic_id, &pr->id);
	if (ret)
	goto out;

	ret = arch_register_cpu(pr->id);
	if (ret) {
	acpi_unmap_lsapic(pr->id);
	goto out;
	}

	/*
	* CPU got hot-added, but cpu_data is not initialized yet. Set a flag
	* to delay cpu_idle/throttling initialization and do it when the CPU
	* gets online for the first time.
	*/
	pr_info("CPU%d has been hot-added\n", pr->id);
	pr->flags.need_hotplug_init = 1;

	out:
	cpu_hotplug_done();
	cpu_maps_update_done();
	return ret;
	}
	#else
	static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
	{
	return -ENODEV;
	}
	#endif /* CONFIG_ACPI_HOTPLUG_CPU */

	static int acpi_processor_get_info(struct acpi_device *device)
	{
	union acpi_object object = { 0 };
	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
	struct acpi_processor *pr = acpi_driver_data(device);
	int apic_id, cpu_index, device_declaration = 0;
	acpi_status status = AE_OK;
	static int cpu0_initialized;
	unsigned long long value;

	acpi_processor_errata();

	/*
	* Check to see if we have bus mastering arbitration control. This
	* is required for proper C3 usage (to maintain cache coherency).
	*/
	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
	pr->flags.bm_control = 1;
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Bus mastering arbitration control present\n"));
	} else
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"No bus mastering arbitration control\n"));

	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
	/* Declared with "Processor" statement; match ProcessorID */
	status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
	if (ACPI_FAILURE(status)) {
	dev_err(&device->dev,
	"Failed to evaluate processor object (0x%x)\n",
	status);
	return -ENODEV;
	}

	pr->acpi_id = object.processor.proc_id;
	} else {
	/*
	* Declared with "Device" statement; match _UID.
	* Note that we don't handle string _UIDs yet.
	*/
	status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
	NULL, &value);
	if (ACPI_FAILURE(status)) {
	dev_err(&device->dev,
	"Failed to evaluate processor _UID (0x%x)\n",
	status);
	return -ENODEV;
	}
	device_declaration = 1;
	pr->acpi_id = value;
	}

	apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id);
	if (apic_id < 0)
	acpi_handle_debug(pr->handle, "failed to get CPU APIC ID.\n");
	pr->apic_id = apic_id;

	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
	if (!cpu0_initialized) {
	cpu0_initialized = 1;
	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
	if ((cpu_index == -1) && (num_online_cpus() == 1))
	cpu_index = 0;
	}
	pr->id = cpu_index;

	/*
	* Extra Processor objects may be enumerated on MP systems with
	* less than the max # of CPUs. They should be ignored _iff
	* they are physically not present.
	*/
	if (pr->id == -1) {
	int ret = acpi_processor_hotadd_init(pr);
	if (ret)
	return ret;
	}

	/*
	* On some boxes several processors use the same processor bus id.
	* But they are located in different scope. For example:
	* \_SB.SCK0.CPU0
	* \_SB.SCK1.CPU0
	* Rename the processor device bus id. And the new bus id will be
	* generated as the following format:
	* CPU+CPU ID.
	*/
	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
	pr->acpi_id));

	if (!object.processor.pblk_address)
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
	else if (object.processor.pblk_length != 6)
	dev_err(&device->dev, "Invalid PBLK length [%d]\n",
	object.processor.pblk_length);
	else {
	pr->throttling.address = object.processor.pblk_address;
	pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
	pr->throttling.duty_width = acpi_gbl_FADT.duty_width;

	pr->pblk = object.processor.pblk_address;

	/*
	* We don't care about error returns - we just try to mark
	* these reserved so that nobody else is confused into thinking
	* that this region might be unused..
	*
	* (In particular, allocating the IO range for Cardbus)
	*/
	request_region(pr->throttling.address, 6, "ACPI CPU throttle");
	}

	/*
	* If ACPI describes a slot number for this CPU, we can use it to
	* ensure we get the right value in the "physical id" field
	* of /proc/cpuinfo
	*/
	status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
	if (ACPI_SUCCESS(status))
	arch_fix_phys_package_id(pr->id, value);

	return 0;
	}

	/*
	* Do not put anything in here which needs the core to be online.
	* For example MSR access or setting up things which check for cpuinfo_x86
	* (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
	* Such things have to be put in and set up by the processor driver's .probe().
	*/
	static DEFINE_PER_CPU(void *, processor_device_array);

	static int acpi_processor_add(struct acpi_device *device,
	const struct acpi_device_id *id)
	{
	struct acpi_processor *pr;
	struct device *dev;
	int result = 0;

	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
	if (!pr)
	return -ENOMEM;

	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
	result = -ENOMEM;
	goto err_free_pr;
	}

	pr->handle = device->handle;
	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
	device->driver_data = pr;

	result = acpi_processor_get_info(device);
	if (result) /* Processor is not physically present or unavailable */
	return 0;

	#ifdef CONFIG_SMP
	if (pr->id >= setup_max_cpus && pr->id != 0)
	return 0;
	#endif

	BUG_ON(pr->id >= nr_cpu_ids);

	/*
	* Buggy BIOS check.
	* ACPI id of processors can be reported wrongly by the BIOS.
	* Don't trust it blindly
	*/
	if (per_cpu(processor_device_array, pr->id) != NULL &&
	per_cpu(processor_device_array, pr->id) != device) {
	dev_warn(&device->dev,
	"BIOS reported wrong ACPI id %d for the processor\n",
	pr->id);
	/* Give up, but do not abort the namespace scan. */
	goto err;
	}
	/*
	* processor_device_array is not cleared on errors to allow buggy BIOS
	* checks.
	*/
	per_cpu(processor_device_array, pr->id) = device;
	per_cpu(processors, pr->id) = pr;

	dev = get_cpu_device(pr->id);
	if (!dev) {
	result = -ENODEV;
	goto err;
	}

	result = acpi_bind_one(dev, device);
	if (result)
	goto err;

	pr->dev = dev;
	dev->offline = pr->flags.need_hotplug_init;

	/* Trigger the processor driver's .probe() if present. */
	if (device_attach(dev) >= 0)
	return 1;

	dev_err(dev, "Processor driver could not be attached\n");
	acpi_unbind_one(dev);

	err:
	free_cpumask_var(pr->throttling.shared_cpu_map);
	device->driver_data = NULL;
	per_cpu(processors, pr->id) = NULL;
	err_free_pr:
	kfree(pr);
	return result;
	}

	#ifdef CONFIG_ACPI_HOTPLUG_CPU
	/* --------------------------------------------------------------------------
	Removal
	-------------------------------------------------------------------------- */

	static void acpi_processor_remove(struct acpi_device *device)
	{
	struct acpi_processor *pr;

	if (!device \|\| !acpi_driver_data(device))
	return;

	pr = acpi_driver_data(device);
	if (pr->id >= nr_cpu_ids)
	goto out;

	/*
	* The only reason why we ever get here is CPU hot-removal. The CPU is
	* already offline and the ACPI device removal locking prevents it from
	* being put back online at this point.
	*
	* Unbind the driver from the processor device and detach it from the
	* ACPI companion object.
	*/
	device_release_driver(pr->dev);
	acpi_unbind_one(pr->dev);

	/* Clean up. */
	per_cpu(processor_device_array, pr->id) = NULL;
	per_cpu(processors, pr->id) = NULL;

	cpu_maps_update_begin();
	cpu_hotplug_begin();

	/* Remove the CPU. */
	arch_unregister_cpu(pr->id);
	acpi_unmap_lsapic(pr->id);

	cpu_hotplug_done();
	cpu_maps_update_done();

	try_offline_node(cpu_to_node(pr->id));

	out:
	free_cpumask_var(pr->throttling.shared_cpu_map);
	kfree(pr);
	}
	#endif /* CONFIG_ACPI_HOTPLUG_CPU */

	/*
	* The following ACPI IDs are known to be suitable for representing as
	* processor devices.
	*/
	static const struct acpi_device_id processor_device_ids[] = {

	{ ACPI_PROCESSOR_OBJECT_HID, },
	{ ACPI_PROCESSOR_DEVICE_HID, },

	{ }
	};

	static struct acpi_scan_handler __refdata processor_handler = {
	.ids = processor_device_ids,
	.attach = acpi_processor_add,
	#ifdef CONFIG_ACPI_HOTPLUG_CPU
	.detach = acpi_processor_remove,
	#endif
	.hotplug = {
	.enabled = true,
	},
	};

	void __init acpi_processor_init(void)
	{
	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
	}