/* * acpi_processor.c - ACPI Processor Driver ($Revision: 71 $) * * Copyright (C) 2001, 2002 Andy Grover * Copyright (C) 2001, 2002 Paul Diefenbaugh * Copyright (C) 2004 Dominik Brodowski * Copyright (C) 2004 Anil S Keshavamurthy * - Added processor hotplug support * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * TBD: * 1. Make # power states dynamic. * 2. Support duty_cycle values that span bit 4. * 3. Optimize by having scheduler determine business instead of * having us try to calculate it here. * 4. Need C1 timing -- must modify kernel (IRQ handler) to get this. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define PREFIX "ACPI: " #define ACPI_PROCESSOR_CLASS "processor" #define ACPI_PROCESSOR_DEVICE_NAME "Processor" #define ACPI_PROCESSOR_FILE_INFO "info" #define ACPI_PROCESSOR_FILE_THROTTLING "throttling" #define ACPI_PROCESSOR_FILE_LIMIT "limit" #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80 #define ACPI_PROCESSOR_NOTIFY_POWER 0x81 #define ACPI_PROCESSOR_NOTIFY_THROTTLING 0x82 #define ACPI_PROCESSOR_DEVICE_HID "ACPI0007" #define ACPI_PROCESSOR_LIMIT_USER 0 #define ACPI_PROCESSOR_LIMIT_THERMAL 1 #define _COMPONENT ACPI_PROCESSOR_COMPONENT ACPI_MODULE_NAME("processor_driver"); MODULE_AUTHOR("Paul Diefenbaugh"); MODULE_DESCRIPTION("ACPI Processor Driver"); MODULE_LICENSE("GPL"); static int acpi_processor_add(struct acpi_device *device); static int acpi_processor_remove(struct acpi_device *device); static void acpi_processor_notify(struct acpi_device *device, u32 event); static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr); static int acpi_processor_handle_eject(struct acpi_processor *pr); static int acpi_processor_start(struct acpi_processor *pr); static const struct acpi_device_id processor_device_ids[] = { {ACPI_PROCESSOR_OBJECT_HID, 0}, {ACPI_PROCESSOR_DEVICE_HID, 0}, {"", 0}, }; MODULE_DEVICE_TABLE(acpi, processor_device_ids); static struct acpi_driver acpi_processor_driver = { .name = "processor", .class = ACPI_PROCESSOR_CLASS, .ids = processor_device_ids, .ops = { .add = acpi_processor_add, .remove = acpi_processor_remove, .notify = acpi_processor_notify, }, }; #define INSTALL_NOTIFY_HANDLER 1 #define UNINSTALL_NOTIFY_HANDLER 2 DEFINE_PER_CPU(struct acpi_processor *, processors); EXPORT_PER_CPU_SYMBOL(processors); struct acpi_processor_errata errata __read_mostly; /* -------------------------------------------------------------------------- Errata Handling -------------------------------------------------------------------------- */ 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; } /* -------------------------------------------------------------------------- Driver Interface -------------------------------------------------------------------------- */ static int acpi_processor_get_info(struct acpi_device *device) { acpi_status status = 0; union acpi_object object = { 0 }; struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; struct acpi_processor *pr; int cpu_index, device_declaration = 0; static int cpu0_initialized; pr = acpi_driver_data(device); if (!pr) return -EINVAL; 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) { if (ACPI_FAILURE(acpi_processor_hotadd_init(pr))) return -ENODEV; } /* * 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 * 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; } static DEFINE_PER_CPU(void *, processor_device_array); static void acpi_processor_notify(struct acpi_device *device, u32 event) { struct acpi_processor *pr = acpi_driver_data(device); int saved; if (!pr) return; switch (event) { case ACPI_PROCESSOR_NOTIFY_PERFORMANCE: saved = pr->performance_platform_limit; acpi_processor_ppc_has_changed(pr, 1); if (saved == pr->performance_platform_limit) break; acpi_bus_generate_proc_event(device, event, pr->performance_platform_limit); acpi_bus_generate_netlink_event(device->pnp.device_class, dev_name(&device->dev), event, pr->performance_platform_limit); break; case ACPI_PROCESSOR_NOTIFY_POWER: acpi_processor_cst_has_changed(pr); acpi_bus_generate_proc_event(device, event, 0); acpi_bus_generate_netlink_event(device->pnp.device_class, dev_name(&device->dev), event, 0); break; case ACPI_PROCESSOR_NOTIFY_THROTTLING: acpi_processor_tstate_has_changed(pr); acpi_bus_generate_proc_event(device, event, 0); acpi_bus_generate_netlink_event(device->pnp.device_class, dev_name(&device->dev), event, 0); break; default: ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported event [0x%x]\n", event)); break; } return; } static int acpi_cpu_soft_notify(struct notifier_block *nfb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; struct acpi_processor *pr = per_cpu(processors, cpu); if (action == CPU_ONLINE && pr) { /* CPU got physically hotplugged and onlined the first time: * Initialize missing things */ if (pr->flags.need_hotplug_init) { pr_info("Will online and init hotplugged CPU: %d\n", pr->id); WARN(acpi_processor_start(pr), "Failed to start CPU:" " %d\n", pr->id); pr->flags.need_hotplug_init = 0; /* Normal CPU soft online event */ } else { acpi_processor_ppc_has_changed(pr, 0); acpi_processor_hotplug(pr); acpi_processor_reevaluate_tstate(pr, action); acpi_processor_tstate_has_changed(pr); } } if (action == CPU_DEAD && pr) { /* invalidate the flag.throttling after one CPU is offline */ acpi_processor_reevaluate_tstate(pr, action); } return NOTIFY_OK; } static struct notifier_block acpi_cpu_notifier = { .notifier_call = acpi_cpu_soft_notify, }; /* * acpi_processor_start() is called by the cpu_hotplug_notifier func: * acpi_cpu_soft_notify(). Getting it __cpuinit{data} is difficult, the * root cause seem to be that acpi_processor_uninstall_hotplug_notify() * is in the module_exit (__exit) func. Allowing acpi_processor_start() * to not be in __cpuinit section, but being called from __cpuinit funcs * via __ref looks like the right thing to do here. */ static __ref int acpi_processor_start(struct acpi_processor *pr) { struct acpi_device *device = per_cpu(processor_device_array, pr->id); int result = 0; #ifdef CONFIG_CPU_FREQ acpi_processor_ppc_has_changed(pr, 0); acpi_processor_load_module(pr); #endif acpi_processor_get_throttling_info(pr); acpi_processor_get_limit_info(pr); if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver) acpi_processor_power_init(pr); pr->cdev = thermal_cooling_device_register("Processor", device, &processor_cooling_ops); if (IS_ERR(pr->cdev)) { result = PTR_ERR(pr->cdev); goto err_power_exit; } dev_dbg(&device->dev, "registered as cooling_device%d\n", pr->cdev->id); result = sysfs_create_link(&device->dev.kobj, &pr->cdev->device.kobj, "thermal_cooling"); if (result) { dev_err(&device->dev, "Failed to create sysfs link 'thermal_cooling'\n"); goto err_thermal_unregister; } result = sysfs_create_link(&pr->cdev->device.kobj, &device->dev.kobj, "device"); if (result) { dev_err(&pr->cdev->device, "Failed to create sysfs link 'device'\n"); goto err_remove_sysfs_thermal; } return 0; err_remove_sysfs_thermal: sysfs_remove_link(&device->dev.kobj, "thermal_cooling"); err_thermal_unregister: thermal_cooling_device_unregister(pr->cdev); err_power_exit: acpi_processor_power_exit(pr); return result; } /* * 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 above in acpi_processor_start() */ static int __cpuinit acpi_processor_add(struct acpi_device *device) { struct acpi_processor *pr = NULL; int result = 0; struct device *dev; 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 physically not present */ 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); result = -ENODEV; goto err_free_cpumask; } per_cpu(processor_device_array, pr->id) = device; per_cpu(processors, pr->id) = pr; dev = get_cpu_device(pr->id); if (sysfs_create_link(&device->dev.kobj, &dev->kobj, "sysdev")) { result = -EFAULT; goto err_clear_processor; } /* * Do not start hotplugged CPUs now, but when they * are onlined the first time */ if (pr->flags.need_hotplug_init) return 0; result = acpi_processor_start(pr); if (result) goto err_remove_sysfs; return 0; err_remove_sysfs: sysfs_remove_link(&device->dev.kobj, "sysdev"); err_clear_processor: /* * processor_device_array is not cleared to allow checks for buggy BIOS */ per_cpu(processors, pr->id) = NULL; err_free_cpumask: free_cpumask_var(pr->throttling.shared_cpu_map); err_free_pr: kfree(pr); return result; } static int acpi_processor_remove(struct acpi_device *device) { struct acpi_processor *pr = NULL; if (!device || !acpi_driver_data(device)) return -EINVAL; pr = acpi_driver_data(device); if (pr->id >= nr_cpu_ids) goto free; if (device->removal_type == ACPI_BUS_REMOVAL_EJECT) { if (acpi_processor_handle_eject(pr)) return -EINVAL; } acpi_processor_power_exit(pr); sysfs_remove_link(&device->dev.kobj, "sysdev"); if (pr->cdev) { sysfs_remove_link(&device->dev.kobj, "thermal_cooling"); sysfs_remove_link(&pr->cdev->device.kobj, "device"); thermal_cooling_device_unregister(pr->cdev); pr->cdev = NULL; } per_cpu(processors, pr->id) = NULL; per_cpu(processor_device_array, pr->id) = NULL; try_offline_node(cpu_to_node(pr->id)); free: free_cpumask_var(pr->throttling.shared_cpu_map); kfree(pr); return 0; } #ifdef CONFIG_ACPI_HOTPLUG_CPU /**************************************************************************** * Acpi processor hotplug support * ****************************************************************************/ static int is_processor_present(acpi_handle handle) { acpi_status status; unsigned long long sta = 0; status = acpi_evaluate_integer(handle, "_STA", NULL, &sta); if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT)) return 1; /* * _STA is mandatory for a processor that supports hot plug */ if (status == AE_NOT_FOUND) ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor does not support hot plug\n")); else ACPI_EXCEPTION((AE_INFO, status, "Processor Device is not present")); return 0; } static void acpi_processor_hotplug_notify(acpi_handle handle, u32 event, void *data) { struct acpi_device *device = NULL; struct acpi_eject_event *ej_event = NULL; u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */ acpi_status status; int result; acpi_scan_lock_acquire(); switch (event) { case ACPI_NOTIFY_BUS_CHECK: case ACPI_NOTIFY_DEVICE_CHECK: ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor driver received %s event\n", (event == ACPI_NOTIFY_BUS_CHECK) ? "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK")); if (!is_processor_present(handle)) break; if (!acpi_bus_get_device(handle, &device)) break; result = acpi_bus_scan(handle); if (result) { acpi_handle_err(handle, "Unable to add the device\n"); break; } result = acpi_bus_get_device(handle, &device); if (result) { acpi_handle_err(handle, "Missing device object\n"); break; } ost_code = ACPI_OST_SC_SUCCESS; break; case ACPI_NOTIFY_EJECT_REQUEST: ACPI_DEBUG_PRINT((ACPI_DB_INFO, "received ACPI_NOTIFY_EJECT_REQUEST\n")); if (acpi_bus_get_device(handle, &device)) { acpi_handle_err(handle, "Device don't exist, dropping EJECT\n"); break; } if (!acpi_driver_data(device)) { acpi_handle_err(handle, "Driver data is NULL, dropping EJECT\n"); break; } ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL); if (!ej_event) { acpi_handle_err(handle, "No memory, dropping EJECT\n"); break; } get_device(&device->dev); ej_event->device = device; ej_event->event = ACPI_NOTIFY_EJECT_REQUEST; /* The eject is carried out asynchronously. */ status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event); if (ACPI_FAILURE(status)) { put_device(&device->dev); kfree(ej_event); break; } goto out; default: ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported event [0x%x]\n", event)); /* non-hotplug event; possibly handled by other handler */ goto out; } /* Inform firmware that the hotplug operation has completed */ (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL); out: acpi_scan_lock_release(); } static acpi_status is_processor_device(acpi_handle handle) { struct acpi_device_info *info; char *hid; acpi_status status; status = acpi_get_object_info(handle, &info); if (ACPI_FAILURE(status)) return status; if (info->type == ACPI_TYPE_PROCESSOR) { kfree(info); return AE_OK; /* found a processor object */ } if (!(info->valid & ACPI_VALID_HID)) { kfree(info); return AE_ERROR; } hid = info->hardware_id.string; if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) { kfree(info); return AE_ERROR; } kfree(info); return AE_OK; /* found a processor device object */ } static acpi_status processor_walk_namespace_cb(acpi_handle handle, u32 lvl, void *context, void **rv) { acpi_status status; int *action = context; status = is_processor_device(handle); if (ACPI_FAILURE(status)) return AE_OK; /* not a processor; continue to walk */ switch (*action) { case INSTALL_NOTIFY_HANDLER: acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, acpi_processor_hotplug_notify, NULL); break; case UNINSTALL_NOTIFY_HANDLER: acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY, acpi_processor_hotplug_notify); break; default: break; } /* found a processor; skip walking underneath */ return AE_CTRL_DEPTH; } static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr) { acpi_handle handle = pr->handle; if (!is_processor_present(handle)) { return AE_ERROR; } if (acpi_map_lsapic(handle, &pr->id)) return AE_ERROR; if (arch_register_cpu(pr->id)) { acpi_unmap_lsapic(pr->id); return AE_ERROR; } /* CPU got hot-plugged, but cpu_data is not initialized yet * Set flag to delay cpu_idle/throttling initialization * in: * acpi_processor_add() * acpi_processor_get_info() * and do it when the CPU gets online the first time * TBD: Cleanup above functions and try to do this more elegant. */ pr_info("CPU %d got hotplugged\n", pr->id); pr->flags.need_hotplug_init = 1; return AE_OK; } static int acpi_processor_handle_eject(struct acpi_processor *pr) { if (cpu_online(pr->id)) cpu_down(pr->id); get_online_cpus(); /* * The cpu might become online again at this point. So we check whether * the cpu has been onlined or not. If the cpu became online, it means * that someone wants to use the cpu. So acpi_processor_handle_eject() * returns -EAGAIN. */ if (unlikely(cpu_online(pr->id))) { put_online_cpus(); pr_warn("Failed to remove CPU %d, because other task " "brought the CPU back online\n", pr->id); return -EAGAIN; } arch_unregister_cpu(pr->id); acpi_unmap_lsapic(pr->id); put_online_cpus(); return (0); } #else static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr) { return AE_ERROR; } static int acpi_processor_handle_eject(struct acpi_processor *pr) { return (-EINVAL); } #endif static void acpi_processor_install_hotplug_notify(void) { #ifdef CONFIG_ACPI_HOTPLUG_CPU int action = INSTALL_NOTIFY_HANDLER; acpi_walk_namespace(ACPI_TYPE_ANY, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX, processor_walk_namespace_cb, NULL, &action, NULL); #endif register_hotcpu_notifier(&acpi_cpu_notifier); } static void acpi_processor_uninstall_hotplug_notify(void) { #ifdef CONFIG_ACPI_HOTPLUG_CPU int action = UNINSTALL_NOTIFY_HANDLER; acpi_walk_namespace(ACPI_TYPE_ANY, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX, processor_walk_namespace_cb, NULL, &action, NULL); #endif unregister_hotcpu_notifier(&acpi_cpu_notifier); } /* * We keep the driver loaded even when ACPI is not running. * This is needed for the powernow-k8 driver, that works even without * ACPI, but needs symbols from this driver */ static int __init acpi_processor_init(void) { int result = 0; if (acpi_disabled) return 0; result = acpi_bus_register_driver(&acpi_processor_driver); if (result < 0) return result; acpi_processor_syscore_init(); acpi_processor_install_hotplug_notify(); acpi_thermal_cpufreq_init(); acpi_processor_ppc_init(); acpi_processor_throttling_init(); return 0; } static void __exit acpi_processor_exit(void) { if (acpi_disabled) return; acpi_processor_ppc_exit(); acpi_thermal_cpufreq_exit(); acpi_processor_uninstall_hotplug_notify(); acpi_processor_syscore_exit(); acpi_bus_unregister_driver(&acpi_processor_driver); return; } module_init(acpi_processor_init); module_exit(acpi_processor_exit); MODULE_ALIAS("processor");