xref: /linux/drivers/acpi/acpi_processor.c (revision 59e6295fac26b8e85c1ea859cdd89fa1e47519d7)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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>
 */
#define pr_fmt(fmt) "ACPI: " fmt

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

#include <acpi/processor.h>

#include <asm/cpu.h>

#include <xen/xen.h>

#include "internal.h"

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);

acpi_handle acpi_get_processor_handle(int cpu)
{
	struct acpi_processor *pr;

	pr = per_cpu(processors, cpu);
	if (pr)
		return pr->handle;

	return NULL;
}

static int acpi_processor_errata_piix4(struct pci_dev *dev)
{
	if (!dev)
		return -EINVAL;

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

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

	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);
			if (errata.piix4.bmisx)
				dev_dbg(&dev->dev,
					"Bus master activity detection (BM-IDE) erratum enabled\n");

			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) {
			u8 value1 = 0, value2 = 0;

			pci_read_config_byte(dev, 0x76, &value1);
			pci_read_config_byte(dev, 0x77, &value2);
			if ((value1 & 0x80) || (value2 & 0x80)) {
				errata.piix4.fdma = 1;
				dev_dbg(&dev->dev,
					"Type-F DMA livelock erratum (C3 disabled)\n");
			}
			pci_dev_put(dev);
		}

		break;
	}

	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;
}

/* Create a platform device to represent a CPU frequency control mechanism. */
static void cpufreq_add_device(const char *name)
{
	struct platform_device *pdev;

	pdev = platform_device_register_simple(name, PLATFORM_DEVID_NONE, NULL, 0);
	if (IS_ERR(pdev))
		pr_info("%s device creation failed: %pe\n", name, pdev);
}

#ifdef CONFIG_X86
/* Check presence of Processor Clocking Control by searching for \_SB.PCCH. */
static void __init acpi_pcc_cpufreq_init(void)
{
	acpi_status status;
	acpi_handle handle;

	status = acpi_get_handle(NULL, "\\_SB", &handle);
	if (ACPI_FAILURE(status))
		return;

	if (acpi_has_method(handle, "PCCH"))
		cpufreq_add_device("pcc-cpufreq");
}
#else
static void __init acpi_pcc_cpufreq_init(void) {}
#endif /* CONFIG_X86 */

/* Initialization */
static DEFINE_PER_CPU(void *, processor_device_array);

static int acpi_processor_set_per_cpu(struct acpi_processor *pr,
				      struct acpi_device *device)
{
	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);
		return -EINVAL;
	}
	/*
	 * 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;

	return 0;
}

#ifdef CONFIG_ACPI_HOTPLUG_CPU
static int acpi_processor_hotadd_init(struct acpi_processor *pr,
				      struct acpi_device *device)
{
	int ret;

	if (invalid_phys_cpuid(pr->phys_id))
		return -ENODEV;

	cpu_maps_update_begin();
	cpus_write_lock();

	ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);
	if (ret)
		goto out;

	ret = acpi_processor_set_per_cpu(pr, device);
	if (ret) {
		acpi_unmap_cpu(pr->id);
		goto out;
	}

	ret = arch_register_cpu(pr->id);
	if (ret) {
		/* Leave the processor device array in place to detect buggy bios */
		per_cpu(processors, pr->id) = NULL;
		acpi_unmap_cpu(pr->id);
		goto out;
	}

	/*
	 * CPU got hot-added, but cpu_data is not initialized yet. Do
	 * cpu_idle/throttling initialization when the CPU gets online for
	 * the first time.
	 */
	pr_info("CPU%d has been hot-added\n", pr->id);

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

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

	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;
		dev_dbg(&device->dev, "Bus mastering arbitration control present\n");
	} else
		dev_dbg(&device->dev, "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.
		 */
		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;
	}

	if (acpi_duplicate_processor_id(pr->acpi_id)) {
		if (pr->acpi_id == 0xff)
			dev_info_once(&device->dev,
				"Entry not well-defined, consider updating BIOS\n");
		else
			dev_err(&device->dev,
				"Failed to get unique processor _UID (0x%x)\n",
				pr->acpi_id);
		return -ENODEV;
	}

	pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
					pr->acpi_id);
	if (invalid_phys_cpuid(pr->phys_id))
		dev_dbg(&device->dev, "Failed to get CPU physical ID.\n");

	pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);
	if (!cpu0_initialized) {
		cpu0_initialized = 1;
		/*
		 * Handle UP system running SMP kernel, with no CPU
		 * entry in MADT
		 */
		if (!acpi_has_cpu_in_madt() && invalid_logical_cpuid(pr->id) &&
		    (num_online_cpus() == 1))
			pr->id = 0;
		/*
		 * Check availability of Processor Performance Control by
		 * looking at the presence of the _PCT object under the first
		 * processor definition.
		 */
		if (acpi_has_method(pr->handle, "_PCT"))
			cpufreq_add_device("acpi-cpufreq");
	}

	/*
	 *  This code is not called unless we know the CPU is present and
	 *  enabled. The two paths are:
	 *  a) Initially present CPUs on architectures that do not defer
	 *     their arch_register_cpu() calls until this point.
	 *  b) Hotplugged CPUs (enabled bit in _STA has transitioned from not
	 *     enabled to enabled)
	 */
	if (!get_cpu_device(pr->id))
		ret = acpi_processor_hotadd_init(pr, device);
	else
		ret = acpi_processor_set_per_cpu(pr, device);
	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);
	dev_dbg(&device->dev, "Processor [%d:%d]\n", pr->id, pr->acpi_id);

	if (!object.processor.pblk_address)
		dev_dbg(&device->dev, "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;
	}

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

	if (!acpi_device_is_enabled(device))
		return -ENODEV;

	pr = kzalloc_obj(struct acpi_processor);
	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;
	device->driver_data = pr;

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

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

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

	pr->dev = dev;

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

#ifdef CONFIG_ACPI_HOTPLUG_CPU
/* Removal */
static void acpi_processor_post_eject(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);

	cpu_maps_update_begin();
	cpus_write_lock();

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

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

	cpus_write_unlock();
	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 */

#ifdef CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC
bool __init processor_physically_present(acpi_handle handle)
{
	int cpuid, type;
	u32 acpi_id;
	acpi_status status;
	acpi_object_type acpi_type;
	unsigned long long tmp;
	union acpi_object object = {};
	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };

	status = acpi_get_type(handle, &acpi_type);
	if (ACPI_FAILURE(status))
		return false;

	switch (acpi_type) {
	case ACPI_TYPE_PROCESSOR:
		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
		if (ACPI_FAILURE(status))
			return false;
		acpi_id = object.processor.proc_id;
		break;
	case ACPI_TYPE_DEVICE:
		status = acpi_evaluate_integer(handle, METHOD_NAME__UID,
					       NULL, &tmp);
		if (ACPI_FAILURE(status))
			return false;
		acpi_id = tmp;
		break;
	default:
		return false;
	}

	if (xen_initial_domain())
		/*
		 * When running as a Xen dom0 the number of processors Linux
		 * sees can be different from the real number of processors on
		 * the system, and we still need to execute _PDC or _OSC for
		 * all of them.
		 */
		return xen_processor_present(acpi_id);

	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
	cpuid = acpi_get_cpuid(handle, type, acpi_id);

	return !invalid_logical_cpuid(cpuid);
}

/* vendor specific UUID indicating an Intel platform */
static u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";

static acpi_status __init acpi_processor_osc(acpi_handle handle, u32 lvl,
					     void *context, void **rv)
{
	u32 capbuf[2] = {};
	struct acpi_osc_context osc_context = {
		.uuid_str = sb_uuid_str,
		.rev = 1,
		.cap.length = 8,
		.cap.pointer = capbuf,
	};
	acpi_status status;

	if (!processor_physically_present(handle))
		return AE_OK;

	arch_acpi_set_proc_cap_bits(&capbuf[OSC_SUPPORT_DWORD]);

	status = acpi_run_osc(handle, &osc_context);
	if (ACPI_FAILURE(status))
		return status;

	kfree(osc_context.ret.pointer);

	return AE_OK;
}

static bool __init acpi_early_processor_osc(void)
{
	acpi_status status;

	acpi_proc_quirk_mwait_check();

	status = acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
				     ACPI_UINT32_MAX, acpi_processor_osc, NULL,
				     NULL, NULL);
	if (ACPI_FAILURE(status))
		return false;

	status = acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_osc,
				  NULL, NULL);
	if (ACPI_FAILURE(status))
		return false;

	return true;
}

void __init acpi_early_processor_control_setup(void)
{
	if (acpi_early_processor_osc()) {
		pr_debug("_OSC evaluated successfully for all CPUs\n");
	} else {
		pr_debug("_OSC evaluation for CPUs failed, trying _PDC\n");
		acpi_early_processor_set_pdc();
	}
}
#endif

/*
 * 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 processor_handler = {
	.ids = processor_device_ids,
	.attach = acpi_processor_add,
#ifdef CONFIG_ACPI_HOTPLUG_CPU
	.post_eject = acpi_processor_post_eject,
#endif
	.hotplug = {
		.enabled = true,
	},
};

static int acpi_processor_container_attach(struct acpi_device *dev,
					   const struct acpi_device_id *id)
{
	return 1;
}

static const struct acpi_device_id processor_container_ids[] = {
	{ ACPI_PROCESSOR_CONTAINER_HID, },
	{ }
};

static struct acpi_scan_handler processor_container_handler = {
	.ids = processor_container_ids,
	.attach = acpi_processor_container_attach,
};

/* The number of the unique processor IDs */
static int nr_unique_ids __initdata;

/* The number of the duplicate processor IDs */
static int nr_duplicate_ids;

/* Used to store the unique processor IDs */
static int unique_processor_ids[] __initdata = {
	[0 ... NR_CPUS - 1] = -1,
};

/* Used to store the duplicate processor IDs */
static int duplicate_processor_ids[] = {
	[0 ... NR_CPUS - 1] = -1,
};

static void __init processor_validated_ids_update(int proc_id)
{
	int i;

	if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
		return;

	/*
	 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
	 * already in the IDs, do nothing.
	 */
	for (i = 0; i < nr_duplicate_ids; i++) {
		if (duplicate_processor_ids[i] == proc_id)
			return;
	}

	/*
	 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
	 * the IDs, put it in the duplicate IDs.
	 */
	for (i = 0; i < nr_unique_ids; i++) {
		if (unique_processor_ids[i] == proc_id) {
			duplicate_processor_ids[nr_duplicate_ids] = proc_id;
			nr_duplicate_ids++;
			return;
		}
	}

	/*
	 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
	 */
	unique_processor_ids[nr_unique_ids] = proc_id;
	nr_unique_ids++;
}

static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
						  u32 lvl,
						  void *context,
						  void **rv)
{
	acpi_status status;
	acpi_object_type acpi_type;
	unsigned long long uid;
	union acpi_object object = { 0 };
	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };

	status = acpi_get_type(handle, &acpi_type);
	if (ACPI_FAILURE(status))
		return status;

	switch (acpi_type) {
	case ACPI_TYPE_PROCESSOR:
		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
		if (ACPI_FAILURE(status))
			goto err;
		uid = object.processor.proc_id;
		break;

	case ACPI_TYPE_DEVICE:
		status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
		if (ACPI_FAILURE(status))
			goto err;
		break;
	default:
		goto err;
	}

	processor_validated_ids_update(uid);
	return AE_OK;

err:
	/* Exit on error, but don't abort the namespace walk */
	acpi_handle_info(handle, "Invalid processor object\n");
	return AE_OK;

}

static void __init acpi_processor_check_duplicates(void)
{
	/* check the correctness for all processors in ACPI namespace */
	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
						ACPI_UINT32_MAX,
						acpi_processor_ids_walk,
						NULL, NULL, NULL);
	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
						NULL, NULL);
}

bool acpi_duplicate_processor_id(int proc_id)
{
	int i;

	/*
	 * compare the proc_id with duplicate IDs, if the proc_id is already
	 * in the duplicate IDs, return true, otherwise, return false.
	 */
	for (i = 0; i < nr_duplicate_ids; i++) {
		if (duplicate_processor_ids[i] == proc_id)
			return true;
	}
	return false;
}

void __init acpi_processor_init(void)
{
	acpi_processor_check_duplicates();
	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
	acpi_scan_add_handler(&processor_container_handler);
	acpi_pcc_cpufreq_init();
}

#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
/**
 * acpi_processor_claim_cst_control - Request _CST control from the platform.
 */
bool acpi_processor_claim_cst_control(void)
{
	static bool cst_control_claimed;
	acpi_status status;

	if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
		return true;

	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
				    acpi_gbl_FADT.cst_control, 8);
	if (ACPI_FAILURE(status)) {
		pr_warn("ACPI: Failed to claim processor _CST control\n");
		return false;
	}

	cst_control_claimed = true;
	return true;
}
EXPORT_SYMBOL_NS_GPL(acpi_processor_claim_cst_control, "ACPI_PROCESSOR_IDLE");

/**
 * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
 * @handle: ACPI handle of the processor object containing the _CST.
 * @cpu: The numeric ID of the target CPU.
 * @info: Object write the C-states information into.
 *
 * Extract the C-state information for the given CPU from the output of the _CST
 * control method under the corresponding ACPI processor object (or processor
 * device object) and populate @info with it.
 *
 * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
 * acpi_processor_ffh_cstate_probe() to verify them and update the
 * cpu_cstate_entry data for @cpu.
 */
int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
				struct acpi_processor_power *info)
{
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *cst;
	acpi_status status;
	u64 count;
	int last_index = 0;
	int i, ret = 0;

	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		acpi_handle_debug(handle, "No _CST\n");
		return -ENODEV;
	}

	cst = buffer.pointer;

	/* There must be at least 2 elements. */
	if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
		acpi_handle_warn(handle, "Invalid _CST output\n");
		ret = -EFAULT;
		goto end;
	}

	count = cst->package.elements[0].integer.value;

	/* Validate the number of C-states. */
	if (count < 1 || count != cst->package.count - 1) {
		acpi_handle_warn(handle, "Inconsistent _CST data\n");
		ret = -EFAULT;
		goto end;
	}

	for (i = 1; i <= count; i++) {
		union acpi_object *element;
		union acpi_object *obj;
		struct acpi_power_register *reg;
		struct acpi_processor_cx cx;

		/*
		 * If there is not enough space for all C-states, skip the
		 * excess ones and log a warning.
		 */
		if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
			acpi_handle_warn(handle,
					 "No room for more idle states (limit: %d)\n",
					 ACPI_PROCESSOR_MAX_POWER - 1);
			break;
		}

		memset(&cx, 0, sizeof(cx));

		element = &cst->package.elements[i];
		if (element->type != ACPI_TYPE_PACKAGE) {
			acpi_handle_info(handle, "_CST C%d type(%x) is not package, skip...\n",
					 i, element->type);
			continue;
		}

		if (element->package.count != 4) {
			acpi_handle_info(handle, "_CST C%d package count(%d) is not 4, skip...\n",
					 i, element->package.count);
			continue;
		}

		obj = &element->package.elements[0];

		if (obj->type != ACPI_TYPE_BUFFER) {
			acpi_handle_info(handle, "_CST C%d package element[0] type(%x) is not buffer, skip...\n",
					 i, obj->type);
			continue;
		}

		reg = (struct acpi_power_register *)obj->buffer.pointer;

		obj = &element->package.elements[1];
		if (obj->type != ACPI_TYPE_INTEGER) {
			acpi_handle_info(handle, "_CST C[%d] package element[1] type(%x) is not integer, skip...\n",
					 i, obj->type);
			continue;
		}

		cx.type = obj->integer.value;
		/*
		 * There are known cases in which the _CST output does not
		 * contain C1, so if the type of the first state found is not
		 * C1, leave an empty slot for C1 to be filled in later.
		 */
		if (i == 1 && cx.type != ACPI_STATE_C1)
			last_index = 1;

		cx.address = reg->address;
		cx.index = last_index + 1;

		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
			if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
				/*
				 * In the majority of cases _CST describes C1 as
				 * a FIXED_HARDWARE C-state, but if the command
				 * line forbids using MWAIT, use CSTATE_HALT for
				 * C1 regardless.
				 */
				if (cx.type == ACPI_STATE_C1 &&
				    boot_option_idle_override == IDLE_NOMWAIT) {
					cx.entry_method = ACPI_CSTATE_HALT;
					snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
				} else {
					cx.entry_method = ACPI_CSTATE_FFH;
				}
			} else if (cx.type == ACPI_STATE_C1) {
				/*
				 * In the special case of C1, FIXED_HARDWARE can
				 * be handled by executing the HLT instruction.
				 */
				cx.entry_method = ACPI_CSTATE_HALT;
				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
			} else {
				acpi_handle_info(handle, "_CST C%d declares FIXED_HARDWARE C-state but not supported in hardware, skip...\n",
						 i);
				continue;
			}
		} else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
			cx.entry_method = ACPI_CSTATE_SYSTEMIO;
			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
				 cx.address);
		} else {
			acpi_handle_info(handle, "_CST C%d space_id(%x) neither FIXED_HARDWARE nor SYSTEM_IO, skip...\n",
					 i, reg->space_id);
			continue;
		}

		if (cx.type == ACPI_STATE_C1)
			cx.valid = 1;

		obj = &element->package.elements[2];
		if (obj->type != ACPI_TYPE_INTEGER) {
			acpi_handle_info(handle, "_CST C%d package element[2] type(%x) not integer, skip...\n",
					 i, obj->type);
			continue;
		}

		cx.latency = obj->integer.value;

		obj = &element->package.elements[3];
		if (obj->type != ACPI_TYPE_INTEGER) {
			acpi_handle_info(handle, "_CST C%d package element[3] type(%x) not integer, skip...\n",
					 i, obj->type);
			continue;
		}

		memcpy(&info->states[++last_index], &cx, sizeof(cx));
	}

	acpi_handle_debug(handle, "Found %d idle states\n", last_index);

	info->count = last_index;

end:
	kfree(buffer.pointer);

	return ret;
}
EXPORT_SYMBOL_NS_GPL(acpi_processor_evaluate_cst, "ACPI_PROCESSOR_IDLE");
#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */

#ifdef CONFIG_ACPI_PROCESSOR_IDLE
struct acpi_lpi_states_array {
	unsigned int size;
	unsigned int composite_states_size;
	struct acpi_lpi_state *entries;
	struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
};

static int obj_get_integer(union acpi_object *obj, u32 *value)
{
	if (obj->type != ACPI_TYPE_INTEGER)
		return -EINVAL;

	*value = obj->integer.value;
	return 0;
}

#define lpi_state_debug(handle, message, state_idx)	\
	acpi_handle_debug(handle, message " for _LPI state %u\n", state_idx)

static void process_lpi_state_package(union acpi_object *lpi_pkg,
				      struct acpi_lpi_state *lpi_state,
				      acpi_handle handle,
				      unsigned int state_idx, bool strict)
{
	union acpi_object *lpi_pkg_elem, *obj;

	if (lpi_pkg->type != ACPI_TYPE_PACKAGE || lpi_pkg->package.count < 7)
		return;

	lpi_pkg_elem = lpi_pkg->package.elements;

	/* Get the entry method first and skip the state if that fails. */
	obj = &lpi_pkg_elem[6];
	if (obj->type == ACPI_TYPE_BUFFER) {
		struct acpi_power_register *reg;

		if (obj->buffer.length < sizeof(*reg)) {
			lpi_state_debug(handle, "Invalid register data", state_idx);
			return;
		}

		reg = (struct acpi_power_register *)obj->buffer.pointer;
		if (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
			lpi_state_debug(handle, "Unsupported entry method", state_idx);
			return;
		}

		lpi_state->entry_method = ACPI_CSTATE_FFH;
		lpi_state->address = reg->address;
	} else if (obj->type == ACPI_TYPE_INTEGER) {
		lpi_state->entry_method = ACPI_CSTATE_INTEGER;
		lpi_state->address = obj->integer.value;
	} else {
		lpi_state_debug(handle, "Invalid entry method", state_idx);
		return;
	}

	if (obj_get_integer(&lpi_pkg_elem[0], &lpi_state->min_residency)) {
		if (strict) {
			lpi_state_debug(handle, "No min. residency", state_idx);
			return;
		}

		lpi_state_debug(handle, "Assuming 10 us min. residency", state_idx);
		lpi_state->min_residency = 10;
	}

	if (obj_get_integer(&lpi_pkg_elem[1], &lpi_state->wake_latency)) {
		if (strict) {
			lpi_state_debug(handle, "No wake latency", state_idx);
			return;
		}

		lpi_state_debug(handle, "Assuming 10 us wake latency", state_idx);
		lpi_state->wake_latency = 10;
	}

	if (obj_get_integer(&lpi_pkg_elem[2], &lpi_state->flags))
		lpi_state->flags = 0;

	if (obj_get_integer(&lpi_pkg_elem[3], &lpi_state->arch_flags))
		lpi_state->arch_flags = 0;

	if (obj_get_integer(&lpi_pkg_elem[4], &lpi_state->res_cnt_freq))
		lpi_state->res_cnt_freq = 1;

	if (obj_get_integer(&lpi_pkg_elem[5], &lpi_state->enable_parent_state))
		lpi_state->enable_parent_state = 0;

	/* Skip elements [7-8] i.e. Residency/Usage counters. */

	/*
	 * Avoid out-of-bounds access if the size of the package is less than
	 * expected.
	 */
	if (lpi_pkg->package.count < 10)
		return;

	obj = &lpi_pkg_elem[9];
	if (obj->type == ACPI_TYPE_STRING)
		strscpy(lpi_state->desc, obj->string.pointer, ACPI_CX_DESC_LEN);
}

static int acpi_processor_evaluate_lpi(acpi_handle handle,
				       struct acpi_lpi_states_array *info,
				       bool strict)
{
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *lpi_data, *lpi_pkg;
	unsigned int lpi_pkg_count, state_idx;
	struct acpi_lpi_state *lpi_state;
	acpi_status status;
	int ret = 0;

	status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		acpi_handle_debug(handle, "No _LPI, giving up\n");
		return -ENODEV;
	}

	lpi_data = buffer.pointer;

	/* There must be at least 4 elements = 3 elements + 1 package */
	if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
	    lpi_data->package.count < 4) {
		acpi_handle_debug(handle, "Not enough elements in _LPI\n");
		ret = -ENODATA;
		goto end;
	}

	lpi_pkg_count = lpi_data->package.elements[2].integer.value;

	/* Validate number of power states. */
	if (!lpi_pkg_count || lpi_pkg_count != lpi_data->package.count - 3) {
		acpi_handle_debug(handle, "Invalid _LPI state count\n");
		ret = -ENODATA;
		goto end;
	}

	lpi_state = kzalloc_objs(*lpi_state, lpi_pkg_count);
	if (!lpi_state) {
		ret = -ENOMEM;
		goto end;
	}

	info->size = lpi_pkg_count;
	info->entries = lpi_state;

	/* _LPI State packages start at index 3. */
	lpi_pkg = &lpi_data->package.elements[3];

	for (state_idx = 1; state_idx <= lpi_pkg_count; state_idx++) {
		lpi_state->index = state_idx;
		process_lpi_state_package(lpi_pkg++, lpi_state++, handle,
					  state_idx, strict);
	}

	acpi_handle_debug(handle, "Found %u power states\n", lpi_pkg_count);
end:
	kfree(buffer.pointer);
	return ret;
}

/**
 * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
 *
 * @local: local LPI state
 * @parent: parent LPI state
 * @result: composite LPI state
 */
static bool combine_lpi_states(struct acpi_lpi_state *local,
			       struct acpi_lpi_state *parent,
			       struct acpi_lpi_state *result)
{
	if (parent->entry_method == ACPI_CSTATE_INTEGER) {
		if (!parent->address) /* 0 means autopromotable */
			return false;
		result->address = local->address + parent->address;
	} else {
		result->address = parent->address;
	}

	result->min_residency = max(local->min_residency, parent->min_residency);
	result->wake_latency = local->wake_latency + parent->wake_latency;
	result->enable_parent_state = parent->enable_parent_state;
	result->entry_method = local->entry_method;

	result->flags = parent->flags;
	result->arch_flags = parent->arch_flags;
	result->index = parent->index;

	scnprintf(result->desc, ACPI_CX_DESC_LEN, "%s+%s", local->desc, parent->desc);
	return true;
}

#define ACPI_LPI_STATE_FLAGS_ENABLED			BIT(0)

static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
				  struct acpi_lpi_state *t)
{
	curr_level->composite_states[curr_level->composite_states_size++] = t;
}

static bool too_many_states(acpi_handle handle, unsigned int state_count)
{
	if (state_count < ACPI_PROCESSOR_MAX_POWER)
		return false;

	acpi_handle_info(handle, "No space for more _LPI states than %d\n",
			 ACPI_PROCESSOR_MAX_POWER);
	return true;
}

static unsigned int flatten_lpi_states(acpi_handle handle,
				       struct acpi_lpi_state *lpi_states,
				       unsigned int state_count,
				       struct acpi_lpi_states_array *curr,
				       struct acpi_lpi_states_array *prev)
{
	struct acpi_lpi_state *parent_lpi = curr->entries;
	unsigned int j;

	/*
	 * Combine each of the "raw" _LPI states from the current (processor
	 * container) level with all of the composite _LPI states from the
	 * previous (processor or processor container) level.
	 */
	for (j = 0; j < curr->size; j++, parent_lpi++) {
		struct acpi_lpi_state *flpi;
		int i;

		if (!(parent_lpi->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
			continue;

		if (too_many_states(handle, state_count))
			break;

		flpi = &lpi_states[state_count];

		for (i = 0; i < prev->composite_states_size; i++) {
			struct acpi_lpi_state *local_lpi = prev->composite_states[i];

			if (parent_lpi->index > local_lpi->enable_parent_state)
				continue;

			if (!combine_lpi_states(local_lpi, parent_lpi, flpi))
				continue;

			stash_composite_state(curr, flpi);
			state_count++;
			flpi++;

			if (state_count >= ACPI_PROCESSOR_MAX_POWER)
				break;
		}
	}

	return state_count;
}

int acpi_processor_extract_lpi_info(acpi_handle pr_handle,
				    struct acpi_processor_power *pr_power,
				    bool strict)
{
	struct acpi_lpi_states_array info[2], *prev, *curr;
	acpi_handle handle = pr_handle;
	unsigned int state_count = 0;
	unsigned int i;
	int ret;

	if (!osc_pc_lpi_support_confirmed)
		return -EOPNOTSUPP;

	curr = &info[0];
	curr->composite_states_size = 0;

	ret = acpi_processor_evaluate_lpi(handle, curr, strict);
	if (ret)
		return ret;

	/* Copy all of the usable first-level states to power.lpi_states[]. */
	for (i = 0; i < curr->size; i++) {
		struct acpi_lpi_state *lpi = &curr->entries[i];
		struct acpi_lpi_state *flpi;

		/*
		 * Skip states that are not enabled or have an inadequate entry
		 * method for this level.
		 */
		if (!(lpi->flags & ACPI_LPI_STATE_FLAGS_ENABLED) ||
		    lpi->entry_method == ACPI_CSTATE_INTEGER)
			continue;

		if (too_many_states(pr_handle, state_count))
			break;

		flpi = &pr_power->lpi_states[state_count++];
		memcpy(flpi, lpi, sizeof(*lpi));
		stash_composite_state(curr, flpi);
	}

	kfree(curr->entries);

	/*
	 * If there are no _LPI states at the first level, there are no _LPI
	 * states at all.
	 */
	if (!state_count)
		return -ENODATA;

	prev = curr;
	curr = &info[1];

	for (;;) {
		struct acpi_lpi_states_array *tmp;
		struct acpi_device *d;

		if (ACPI_FAILURE(acpi_get_parent(handle, &handle)))
			break;

		d = acpi_fetch_acpi_dev(handle);
		if (!d)
			break;

		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
			break;

		curr->composite_states_size = 0;

		ret = acpi_processor_evaluate_lpi(handle, curr, strict);
		if (ret)
			break;

		/* flatten all the LPI states in this level of hierarchy */
		state_count = flatten_lpi_states(pr_handle, pr_power->lpi_states,
						 state_count, curr, prev);

		kfree(curr->entries);

		tmp = prev, prev = curr, curr = tmp;
	}

	/* reset the index after flattening */
	for (i = 0; i < state_count; i++)
		pr_power->lpi_states[i].index = i;

	pr_power->count = state_count;

	return 0;
}
EXPORT_SYMBOL_NS_GPL(acpi_processor_extract_lpi_info, "ACPI_PROCESSOR_IDLE");
#endif /* CONFIG_ACPI_PROCESSOR_IDLE */