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![Toshi Kani](/assets/img/avatar_default.png)
During CPU online/offline testing on a large system, one of the processors got stuck after the message "bad: scheduling from the idle thread!". The problem is that acpi_cpu_soft_notify() calls acpi_bus_get_device() for all action types. CPU_STARTING and CPU_DYING do not allow the notify handlers to sleep. However, acpi_bus_get_device() can sleep in acpi_ut_acquire_mutex(). Change acpi_cpu_soft_notify() to return immediately for CPU_STARTING and CPU_DYING as they have no action in this handler. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
306 lines
8.1 KiB
C
306 lines
8.1 KiB
C
/*
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* processor_driver.c - ACPI Processor Driver
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*
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* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
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* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
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* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
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* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
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* - Added processor hotplug support
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* Copyright (C) 2013, Intel Corporation
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* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/cpu.h>
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#include <linux/cpuidle.h>
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#include <linux/slab.h>
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#include <linux/acpi.h>
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#include <acpi/processor.h>
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#include "internal.h"
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#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
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#define ACPI_PROCESSOR_NOTIFY_POWER 0x81
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#define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82
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#define _COMPONENT ACPI_PROCESSOR_COMPONENT
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ACPI_MODULE_NAME("processor_driver");
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MODULE_AUTHOR("Paul Diefenbaugh");
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MODULE_DESCRIPTION("ACPI Processor Driver");
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MODULE_LICENSE("GPL");
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static int acpi_processor_start(struct device *dev);
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static int acpi_processor_stop(struct device *dev);
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static const struct acpi_device_id processor_device_ids[] = {
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{ACPI_PROCESSOR_OBJECT_HID, 0},
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{ACPI_PROCESSOR_DEVICE_HID, 0},
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{"", 0},
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};
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MODULE_DEVICE_TABLE(acpi, processor_device_ids);
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static struct device_driver acpi_processor_driver = {
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.name = "processor",
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.bus = &cpu_subsys,
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.acpi_match_table = processor_device_ids,
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.probe = acpi_processor_start,
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.remove = acpi_processor_stop,
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};
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static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
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{
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struct acpi_device *device = data;
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struct acpi_processor *pr;
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int saved;
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if (device->handle != handle)
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return;
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pr = acpi_driver_data(device);
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if (!pr)
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return;
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switch (event) {
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case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
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saved = pr->performance_platform_limit;
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acpi_processor_ppc_has_changed(pr, 1);
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if (saved == pr->performance_platform_limit)
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break;
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acpi_bus_generate_netlink_event(device->pnp.device_class,
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dev_name(&device->dev), event,
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pr->performance_platform_limit);
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break;
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case ACPI_PROCESSOR_NOTIFY_POWER:
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acpi_processor_cst_has_changed(pr);
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acpi_bus_generate_netlink_event(device->pnp.device_class,
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dev_name(&device->dev), event, 0);
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break;
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case ACPI_PROCESSOR_NOTIFY_THROTTLING:
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acpi_processor_tstate_has_changed(pr);
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acpi_bus_generate_netlink_event(device->pnp.device_class,
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dev_name(&device->dev), event, 0);
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break;
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default:
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Unsupported event [0x%x]\n", event));
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break;
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}
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return;
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}
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static int __acpi_processor_start(struct acpi_device *device);
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static int acpi_cpu_soft_notify(struct notifier_block *nfb,
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unsigned long action, void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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struct acpi_processor *pr = per_cpu(processors, cpu);
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struct acpi_device *device;
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/*
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* CPU_STARTING and CPU_DYING must not sleep. Return here since
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* acpi_bus_get_device() may sleep.
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*/
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if (action == CPU_STARTING || action == CPU_DYING)
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return NOTIFY_DONE;
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if (!pr || acpi_bus_get_device(pr->handle, &device))
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return NOTIFY_DONE;
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if (action == CPU_ONLINE) {
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/*
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* CPU got physically hotplugged and onlined for the first time:
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* Initialize missing things.
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*/
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if (pr->flags.need_hotplug_init) {
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int ret;
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pr_info("Will online and init hotplugged CPU: %d\n",
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pr->id);
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pr->flags.need_hotplug_init = 0;
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ret = __acpi_processor_start(device);
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WARN(ret, "Failed to start CPU: %d\n", pr->id);
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} else {
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/* Normal CPU soft online event. */
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acpi_processor_ppc_has_changed(pr, 0);
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acpi_processor_hotplug(pr);
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acpi_processor_reevaluate_tstate(pr, action);
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acpi_processor_tstate_has_changed(pr);
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}
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} else if (action == CPU_DEAD) {
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/* Invalidate flag.throttling after the CPU is offline. */
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acpi_processor_reevaluate_tstate(pr, action);
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}
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return NOTIFY_OK;
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}
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static struct notifier_block __refdata acpi_cpu_notifier = {
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.notifier_call = acpi_cpu_soft_notify,
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};
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static int __acpi_processor_start(struct acpi_device *device)
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{
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struct acpi_processor *pr = acpi_driver_data(device);
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acpi_status status;
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int result = 0;
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if (!pr)
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return -ENODEV;
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if (pr->flags.need_hotplug_init)
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return 0;
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#ifdef CONFIG_CPU_FREQ
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acpi_processor_ppc_has_changed(pr, 0);
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#endif
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acpi_processor_get_throttling_info(pr);
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if (pr->flags.throttling)
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pr->flags.limit = 1;
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if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
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acpi_processor_power_init(pr);
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pr->cdev = thermal_cooling_device_register("Processor", device,
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&processor_cooling_ops);
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if (IS_ERR(pr->cdev)) {
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result = PTR_ERR(pr->cdev);
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goto err_power_exit;
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}
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dev_dbg(&device->dev, "registered as cooling_device%d\n",
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pr->cdev->id);
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result = sysfs_create_link(&device->dev.kobj,
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&pr->cdev->device.kobj,
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"thermal_cooling");
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if (result) {
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dev_err(&device->dev,
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"Failed to create sysfs link 'thermal_cooling'\n");
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goto err_thermal_unregister;
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}
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result = sysfs_create_link(&pr->cdev->device.kobj,
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&device->dev.kobj,
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"device");
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if (result) {
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dev_err(&pr->cdev->device,
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"Failed to create sysfs link 'device'\n");
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goto err_remove_sysfs_thermal;
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}
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status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
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acpi_processor_notify, device);
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if (ACPI_SUCCESS(status))
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return 0;
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sysfs_remove_link(&pr->cdev->device.kobj, "device");
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err_remove_sysfs_thermal:
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sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
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err_thermal_unregister:
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thermal_cooling_device_unregister(pr->cdev);
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err_power_exit:
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acpi_processor_power_exit(pr);
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return result;
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}
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static int acpi_processor_start(struct device *dev)
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{
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struct acpi_device *device = ACPI_COMPANION(dev);
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if (!device)
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return -ENODEV;
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return __acpi_processor_start(device);
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}
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static int acpi_processor_stop(struct device *dev)
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{
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struct acpi_device *device = ACPI_COMPANION(dev);
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struct acpi_processor *pr;
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if (!device)
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return 0;
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acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
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acpi_processor_notify);
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pr = acpi_driver_data(device);
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if (!pr)
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return 0;
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acpi_processor_power_exit(pr);
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if (pr->cdev) {
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sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
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sysfs_remove_link(&pr->cdev->device.kobj, "device");
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thermal_cooling_device_unregister(pr->cdev);
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pr->cdev = NULL;
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}
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return 0;
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}
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/*
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* We keep the driver loaded even when ACPI is not running.
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* This is needed for the powernow-k8 driver, that works even without
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* ACPI, but needs symbols from this driver
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*/
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static int __init acpi_processor_driver_init(void)
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{
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int result = 0;
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if (acpi_disabled)
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return 0;
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result = driver_register(&acpi_processor_driver);
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if (result < 0)
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return result;
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acpi_processor_syscore_init();
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register_hotcpu_notifier(&acpi_cpu_notifier);
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acpi_thermal_cpufreq_init();
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acpi_processor_ppc_init();
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acpi_processor_throttling_init();
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return 0;
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}
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static void __exit acpi_processor_driver_exit(void)
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{
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if (acpi_disabled)
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return;
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acpi_processor_ppc_exit();
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acpi_thermal_cpufreq_exit();
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unregister_hotcpu_notifier(&acpi_cpu_notifier);
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acpi_processor_syscore_exit();
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driver_unregister(&acpi_processor_driver);
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}
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module_init(acpi_processor_driver_init);
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module_exit(acpi_processor_driver_exit);
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MODULE_ALIAS("processor");
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