Merge tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "This time the total number of ACPI commits is slightly greater than
  the number of cpufreq commits, but Viresh Kumar (who works on cpufreq)
  remains the most active patch submitter.

  To me, the most significant change is the addition of offline/online
  device operations to the driver core (with the Greg's blessing) and
  the related modifications of the ACPI core hotplug code.  Next are the
  freezer updates from Colin Cross that should make the freezing of
  tasks a bit less heavy weight.

  We also have a couple of regression fixes, a number of fixes for
  issues that have not been identified as regressions, two new drivers
  and a bunch of cleanups all over.

  Highlights:

   - Hotplug changes to support graceful hot-removal failures.

     It sometimes is necessary to fail device hot-removal operations
     gracefully if they cannot be carried out completely.  For example,
     if memory from a memory module being hot-removed has been allocated
     for the kernel's own use and cannot be moved elsewhere, it's
     desirable to fail the hot-removal operation in a graceful way
     rather than to crash the kernel, but currenty a success or a kernel
     crash are the only possible outcomes of an attempted memory
     hot-removal.  Needless to say, that is not a very attractive
     alternative and it had to be addressed.

     However, in order to make it work for memory, I first had to make
     it work for CPUs and for this purpose I needed to modify the ACPI
     processor driver.  It's been split into two parts, a resident one
     handling the low-level initialization/cleanup and a modular one
     playing the actual driver's role (but it binds to the CPU system
     device objects rather than to the ACPI device objects representing
     processors).  That's been sort of like a live brain surgery on a
     patient who's riding a bike.

     So this is a little scary, but since we found and fixed a couple of
     regressions it caused to happen during the early linux-next testing
     (a month ago), nobody has complained.

     As a bonus we remove some duplicated ACPI hotplug code, because the
     ACPI-based CPU hotplug is now going to use the common ACPI hotplug
     code.

   - Lighter weight freezing of tasks.

     These changes from Colin Cross and Mandeep Singh Baines are
     targeted at making the freezing of tasks a bit less heavy weight
     operation.  They reduce the number of tasks woken up every time
     during the freezing, by using the observation that the freezer
     simply doesn't need to wake up some of them and wait for them all
     to call refrigerator().  The time needed for the freezer to decide
     to report a failure is reduced too.

     Also reintroduced is the check causing a lockdep warining to
     trigger when try_to_freeze() is called with locks held (which is
     generally unsafe and shouldn't happen).

   - cpufreq updates

     First off, a commit from Srivatsa S Bhat fixes a resume regression
     introduced during the 3.10 cycle causing some cpufreq sysfs
     attributes to return wrong values to user space after resume.  The
     fix is kind of fresh, but also it's pretty obvious once Srivatsa
     has identified the root cause.

     Second, we have a new freqdomain_cpus sysfs attribute for the
     acpi-cpufreq driver to provide information previously available via
     related_cpus.  From Lan Tianyu.

     Finally, we fix a number of issues, mostly related to the
     CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean
     up some code.  The majority of changes from Viresh Kumar with bits
     from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia,
     Arnd Bergmann, and Tang Yuantian.

   - ACPICA update

     A usual bunch of updates from the ACPICA upstream.

     During the 3.4 cycle we introduced support for ACPI 5 extended
     sleep registers, but they are only supposed to be used if the
     HW-reduced mode bit is set in the FADT flags and the code attempted
     to use them without checking that bit.  That caused suspend/resume
     regressions to happen on some systems.  Fix from Lv Zheng causes
     those registers to be used only if the HW-reduced mode bit is set.

     Apart from this some other ACPICA bugs are fixed and code cleanups
     are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and
     Zhang Rui.

   - cpuidle updates

     New driver for Xilinx Zynq processors is added by Michal Simek.

     Multidriver support simplification, addition of some missing
     kerneldoc comments and Kconfig-related fixes come from Daniel
     Lezcano.

   - ACPI power management updates

     Changes to make suspend/resume work correctly in Xen guests from
     Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and
     cleanups and fixes of the ACPI device power state selection
     routine.

   - ACPI documentation updates

     Some previously missing pieces of ACPI documentation are added by
     Lv Zheng and Aaron Lu (hopefully, that will help people to
     uderstand how the ACPI subsystem works) and one outdated doc is
     updated by Hanjun Guo.

   - Assorted ACPI updates

     We finally nailed down the IA-64 issue that was the reason for
     reverting commit 9f29ab11ddbf ("ACPI / scan: do not match drivers
     against objects having scan handlers"), so we can fix it and move
     the ACPI scan handler check added to the ACPI video driver back to
     the core.

     A mechanism for adding CMOS RTC address space handlers is
     introduced by Lan Tianyu to allow some EC-related breakage to be
     fixed on some systems.

     A spec-compliant implementation of acpi_os_get_timer() is added by
     Mika Westerberg.

     The evaluation of _STA is added to do_acpi_find_child() to avoid
     situations in which a pointer to a disabled device object is
     returned instead of an enabled one with the same _ADR value.  From
     Jeff Wu.

     Intel BayTrail PCH (Platform Controller Hub) support is added to
     the ACPI driver for Intel Low-Power Subsystems (LPSS) and that
     driver is modified to work around a couple of known BIOS issues.
     Changes from Mika Westerberg and Heikki Krogerus.

     The EC driver is fixed by Vasiliy Kulikov to use get_user() and
     put_user() instead of dereferencing user space pointers blindly.

     Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi
     Kani.

   - Assorted power management updates

     The "runtime idle" helper routine is changed to take the return
     values of the callbacks executed by it into account and to call
     rpm_suspend() if they return 0, which allows us to reduce the
     overall code bloat a bit (by dropping some code that's not
     necessary any more after that modification).

     The runtime PM documentation is updated by Alan Stern (to reflect
     the "runtime idle" behavior change).

     New trace points for PM QoS are added by Sahara
     (<keun-o.park@windriver.com>).

     PM QoS documentation is updated by Lan Tianyu.

     Code cleanups are made and minor issues are addressed by Bernie
     Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan.

   - devfreq updates

     New driver for the Exynos5-bus device from Abhilash Kesavan.

     Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham,
     Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun.

   - OMAP power management updates

     Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver
     updates from Andrii Tseglytskyi and Nishanth Menon."

* tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
  cpufreq: Fix cpufreq regression after suspend/resume
  ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
  PM / Sleep: Warn about system time after resume with pm_trace
  cpufreq: don't leave stale policy pointer in cdbs->cur_policy
  acpi-cpufreq: Add new sysfs attribute freqdomain_cpus
  cpufreq: make sure frequency transitions are serialized
  ACPI: implement acpi_os_get_timer() according the spec
  ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan
  ACPI: Add CMOS RTC Operation Region handler support
  ACPI / processor: Drop unused variable from processor_perflib.c
  cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases
  cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
  ...

1 files changed, 494 insertions, 0 deletions

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
new file mode 100644
index 0000000..e9b01e3
--- /dev/null
+++ b/drivers/acpi/acpi_processor.c
@@ -0,0 +1,494 @@
+/*
+ * 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(struct acpi_processor *pr)
+{
+	int result = 0;
+	struct pci_dev *dev = NULL;
+
+
+	if (!pr)
+		return -EINVAL;
+
+	/*
+	 * 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;
+
+	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
+	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
+		return -ENODEV;
+
+	ret = acpi_map_lsapic(pr->handle, &pr->id);
+	if (ret)
+		return ret;
+
+	ret = arch_register_cpu(pr->id);
+	if (ret) {
+		acpi_unmap_lsapic(pr->id);
+		return ret;
+	}
+
+	/*
+	 * 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;
+	return 0;
+}
+#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 cpu_index, device_declaration = 0;
+	acpi_status status = AE_OK;
+	static int cpu0_initialized;
+
+	if (num_online_cpus() > 1)
+		errata.smp = TRUE;
+
+	acpi_processor_errata(pr);
+
+	/*
+	 * 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;
+		}
+
+		/*
+		 * TBD: Synch processor ID (via LAPIC/LSAPIC structures) on SMP.
+		 *      >>> 'acpi_get_processor_id(acpi_id, &id)' in
+		 *      arch/xxx/acpi.c
+		 */
+		pr->acpi_id = object.processor.proc_id;
+	} else {
+		/*
+		 * Declared with "Device" statement; match _UID.
+		 * Note that we don't handle string _UIDs yet.
+		 */
+		unsigned long long value;
+		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;
+	}
+	cpu_index = acpi_get_cpuid(pr->handle, device_declaration, pr->acpi_id);
+
+	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
+	if (!cpu0_initialized && (cpu_index == -1) &&
+	    (num_online_cpus() == 1)) {
+		cpu_index = 0;
+	}
+
+	cpu0_initialized = 1;
+
+	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_object(pr->handle, "_SUN", NULL, &buffer);
+	if (ACPI_SUCCESS(status))
+		arch_fix_phys_package_id(pr->id, object.integer.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 __cpuinit 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, pr->handle);
+	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;
+	try_offline_node(cpu_to_node(pr->id));
+
+	/* Remove the CPU. */
+	get_online_cpus();
+	arch_unregister_cpu(pr->id);
+	acpi_unmap_lsapic(pr->id);
+	put_online_cpus();
+
+ 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");
+}