xref: /openbmc/linux/drivers/acpi/acpi_processor.c (revision b593bce5)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * acpi_processor.c - ACPI processor enumeration support
4  *
5  * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  * Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
8  * Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
9  * Copyright (C) 2013, Intel Corporation
10  *                     Rafael J. Wysocki <rafael.j.wysocki@intel.com>
11  */
12 
13 #include <linux/acpi.h>
14 #include <linux/device.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/pci.h>
18 
19 #include <acpi/processor.h>
20 
21 #include <asm/cpu.h>
22 
23 #include "internal.h"
24 
25 #define _COMPONENT	ACPI_PROCESSOR_COMPONENT
26 
27 ACPI_MODULE_NAME("processor");
28 
29 DEFINE_PER_CPU(struct acpi_processor *, processors);
30 EXPORT_PER_CPU_SYMBOL(processors);
31 
32 /* --------------------------------------------------------------------------
33                                 Errata Handling
34    -------------------------------------------------------------------------- */
35 
36 struct acpi_processor_errata errata __read_mostly;
37 EXPORT_SYMBOL_GPL(errata);
38 
39 static int acpi_processor_errata_piix4(struct pci_dev *dev)
40 {
41 	u8 value1 = 0;
42 	u8 value2 = 0;
43 
44 
45 	if (!dev)
46 		return -EINVAL;
47 
48 	/*
49 	 * Note that 'dev' references the PIIX4 ACPI Controller.
50 	 */
51 
52 	switch (dev->revision) {
53 	case 0:
54 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
55 		break;
56 	case 1:
57 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
58 		break;
59 	case 2:
60 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
61 		break;
62 	case 3:
63 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
64 		break;
65 	default:
66 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
67 		break;
68 	}
69 
70 	switch (dev->revision) {
71 
72 	case 0:		/* PIIX4 A-step */
73 	case 1:		/* PIIX4 B-step */
74 		/*
75 		 * See specification changes #13 ("Manual Throttle Duty Cycle")
76 		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
77 		 * erratum #5 ("STPCLK# Deassertion Time") from the January
78 		 * 2002 PIIX4 specification update.  Applies to only older
79 		 * PIIX4 models.
80 		 */
81 		errata.piix4.throttle = 1;
82 		/* fall through*/
83 
84 	case 2:		/* PIIX4E */
85 	case 3:		/* PIIX4M */
86 		/*
87 		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
88 		 * Livelock") from the January 2002 PIIX4 specification update.
89 		 * Applies to all PIIX4 models.
90 		 */
91 
92 		/*
93 		 * BM-IDE
94 		 * ------
95 		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
96 		 * Status register address.  We'll use this later to read
97 		 * each IDE controller's DMA status to make sure we catch all
98 		 * DMA activity.
99 		 */
100 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
101 				     PCI_DEVICE_ID_INTEL_82371AB,
102 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
103 		if (dev) {
104 			errata.piix4.bmisx = pci_resource_start(dev, 4);
105 			pci_dev_put(dev);
106 		}
107 
108 		/*
109 		 * Type-F DMA
110 		 * ----------
111 		 * Find the PIIX4 ISA Controller and read the Motherboard
112 		 * DMA controller's status to see if Type-F (Fast) DMA mode
113 		 * is enabled (bit 7) on either channel.  Note that we'll
114 		 * disable C3 support if this is enabled, as some legacy
115 		 * devices won't operate well if fast DMA is disabled.
116 		 */
117 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
118 				     PCI_DEVICE_ID_INTEL_82371AB_0,
119 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
120 		if (dev) {
121 			pci_read_config_byte(dev, 0x76, &value1);
122 			pci_read_config_byte(dev, 0x77, &value2);
123 			if ((value1 & 0x80) || (value2 & 0x80))
124 				errata.piix4.fdma = 1;
125 			pci_dev_put(dev);
126 		}
127 
128 		break;
129 	}
130 
131 	if (errata.piix4.bmisx)
132 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
133 				  "Bus master activity detection (BM-IDE) erratum enabled\n"));
134 	if (errata.piix4.fdma)
135 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
136 				  "Type-F DMA livelock erratum (C3 disabled)\n"));
137 
138 	return 0;
139 }
140 
141 static int acpi_processor_errata(void)
142 {
143 	int result = 0;
144 	struct pci_dev *dev = NULL;
145 
146 	/*
147 	 * PIIX4
148 	 */
149 	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
150 			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
151 			     PCI_ANY_ID, NULL);
152 	if (dev) {
153 		result = acpi_processor_errata_piix4(dev);
154 		pci_dev_put(dev);
155 	}
156 
157 	return result;
158 }
159 
160 /* --------------------------------------------------------------------------
161                                 Initialization
162    -------------------------------------------------------------------------- */
163 
164 #ifdef CONFIG_ACPI_HOTPLUG_CPU
165 int __weak acpi_map_cpu(acpi_handle handle,
166 		phys_cpuid_t physid, u32 acpi_id, int *pcpu)
167 {
168 	return -ENODEV;
169 }
170 
171 int __weak acpi_unmap_cpu(int cpu)
172 {
173 	return -ENODEV;
174 }
175 
176 int __weak arch_register_cpu(int cpu)
177 {
178 	return -ENODEV;
179 }
180 
181 void __weak arch_unregister_cpu(int cpu) {}
182 
183 static int acpi_processor_hotadd_init(struct acpi_processor *pr)
184 {
185 	unsigned long long sta;
186 	acpi_status status;
187 	int ret;
188 
189 	if (invalid_phys_cpuid(pr->phys_id))
190 		return -ENODEV;
191 
192 	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
193 	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
194 		return -ENODEV;
195 
196 	cpu_maps_update_begin();
197 	cpu_hotplug_begin();
198 
199 	ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);
200 	if (ret)
201 		goto out;
202 
203 	ret = arch_register_cpu(pr->id);
204 	if (ret) {
205 		acpi_unmap_cpu(pr->id);
206 		goto out;
207 	}
208 
209 	/*
210 	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
211 	 * to delay cpu_idle/throttling initialization and do it when the CPU
212 	 * gets online for the first time.
213 	 */
214 	pr_info("CPU%d has been hot-added\n", pr->id);
215 	pr->flags.need_hotplug_init = 1;
216 
217 out:
218 	cpu_hotplug_done();
219 	cpu_maps_update_done();
220 	return ret;
221 }
222 #else
223 static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
224 {
225 	return -ENODEV;
226 }
227 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
228 
229 static int acpi_processor_get_info(struct acpi_device *device)
230 {
231 	union acpi_object object = { 0 };
232 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
233 	struct acpi_processor *pr = acpi_driver_data(device);
234 	int device_declaration = 0;
235 	acpi_status status = AE_OK;
236 	static int cpu0_initialized;
237 	unsigned long long value;
238 
239 	acpi_processor_errata();
240 
241 	/*
242 	 * Check to see if we have bus mastering arbitration control.  This
243 	 * is required for proper C3 usage (to maintain cache coherency).
244 	 */
245 	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
246 		pr->flags.bm_control = 1;
247 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
248 				  "Bus mastering arbitration control present\n"));
249 	} else
250 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
251 				  "No bus mastering arbitration control\n"));
252 
253 	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
254 		/* Declared with "Processor" statement; match ProcessorID */
255 		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
256 		if (ACPI_FAILURE(status)) {
257 			dev_err(&device->dev,
258 				"Failed to evaluate processor object (0x%x)\n",
259 				status);
260 			return -ENODEV;
261 		}
262 
263 		pr->acpi_id = object.processor.proc_id;
264 	} else {
265 		/*
266 		 * Declared with "Device" statement; match _UID.
267 		 * Note that we don't handle string _UIDs yet.
268 		 */
269 		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
270 						NULL, &value);
271 		if (ACPI_FAILURE(status)) {
272 			dev_err(&device->dev,
273 				"Failed to evaluate processor _UID (0x%x)\n",
274 				status);
275 			return -ENODEV;
276 		}
277 		device_declaration = 1;
278 		pr->acpi_id = value;
279 	}
280 
281 	if (acpi_duplicate_processor_id(pr->acpi_id)) {
282 		dev_err(&device->dev,
283 			"Failed to get unique processor _UID (0x%x)\n",
284 			pr->acpi_id);
285 		return -ENODEV;
286 	}
287 
288 	pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
289 					pr->acpi_id);
290 	if (invalid_phys_cpuid(pr->phys_id))
291 		acpi_handle_debug(pr->handle, "failed to get CPU physical ID.\n");
292 
293 	pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);
294 	if (!cpu0_initialized && !acpi_has_cpu_in_madt()) {
295 		cpu0_initialized = 1;
296 		/*
297 		 * Handle UP system running SMP kernel, with no CPU
298 		 * entry in MADT
299 		 */
300 		if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1))
301 			pr->id = 0;
302 	}
303 
304 	/*
305 	 *  Extra Processor objects may be enumerated on MP systems with
306 	 *  less than the max # of CPUs. They should be ignored _iff
307 	 *  they are physically not present.
308 	 *
309 	 *  NOTE: Even if the processor has a cpuid, it may not be present
310 	 *  because cpuid <-> apicid mapping is persistent now.
311 	 */
312 	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
313 		int ret = acpi_processor_hotadd_init(pr);
314 		if (ret)
315 			return ret;
316 	}
317 
318 	/*
319 	 * On some boxes several processors use the same processor bus id.
320 	 * But they are located in different scope. For example:
321 	 * \_SB.SCK0.CPU0
322 	 * \_SB.SCK1.CPU0
323 	 * Rename the processor device bus id. And the new bus id will be
324 	 * generated as the following format:
325 	 * CPU+CPU ID.
326 	 */
327 	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
328 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
329 			  pr->acpi_id));
330 
331 	if (!object.processor.pblk_address)
332 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
333 	else if (object.processor.pblk_length != 6)
334 		dev_err(&device->dev, "Invalid PBLK length [%d]\n",
335 			    object.processor.pblk_length);
336 	else {
337 		pr->throttling.address = object.processor.pblk_address;
338 		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
339 		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
340 
341 		pr->pblk = object.processor.pblk_address;
342 	}
343 
344 	/*
345 	 * If ACPI describes a slot number for this CPU, we can use it to
346 	 * ensure we get the right value in the "physical id" field
347 	 * of /proc/cpuinfo
348 	 */
349 	status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
350 	if (ACPI_SUCCESS(status))
351 		arch_fix_phys_package_id(pr->id, value);
352 
353 	return 0;
354 }
355 
356 /*
357  * Do not put anything in here which needs the core to be online.
358  * For example MSR access or setting up things which check for cpuinfo_x86
359  * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
360  * Such things have to be put in and set up by the processor driver's .probe().
361  */
362 static DEFINE_PER_CPU(void *, processor_device_array);
363 
364 static int acpi_processor_add(struct acpi_device *device,
365 					const struct acpi_device_id *id)
366 {
367 	struct acpi_processor *pr;
368 	struct device *dev;
369 	int result = 0;
370 
371 	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
372 	if (!pr)
373 		return -ENOMEM;
374 
375 	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
376 		result = -ENOMEM;
377 		goto err_free_pr;
378 	}
379 
380 	pr->handle = device->handle;
381 	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
382 	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
383 	device->driver_data = pr;
384 
385 	result = acpi_processor_get_info(device);
386 	if (result) /* Processor is not physically present or unavailable */
387 		return 0;
388 
389 	BUG_ON(pr->id >= nr_cpu_ids);
390 
391 	/*
392 	 * Buggy BIOS check.
393 	 * ACPI id of processors can be reported wrongly by the BIOS.
394 	 * Don't trust it blindly
395 	 */
396 	if (per_cpu(processor_device_array, pr->id) != NULL &&
397 	    per_cpu(processor_device_array, pr->id) != device) {
398 		dev_warn(&device->dev,
399 			"BIOS reported wrong ACPI id %d for the processor\n",
400 			pr->id);
401 		/* Give up, but do not abort the namespace scan. */
402 		goto err;
403 	}
404 	/*
405 	 * processor_device_array is not cleared on errors to allow buggy BIOS
406 	 * checks.
407 	 */
408 	per_cpu(processor_device_array, pr->id) = device;
409 	per_cpu(processors, pr->id) = pr;
410 
411 	dev = get_cpu_device(pr->id);
412 	if (!dev) {
413 		result = -ENODEV;
414 		goto err;
415 	}
416 
417 	result = acpi_bind_one(dev, device);
418 	if (result)
419 		goto err;
420 
421 	pr->dev = dev;
422 
423 	/* Trigger the processor driver's .probe() if present. */
424 	if (device_attach(dev) >= 0)
425 		return 1;
426 
427 	dev_err(dev, "Processor driver could not be attached\n");
428 	acpi_unbind_one(dev);
429 
430  err:
431 	free_cpumask_var(pr->throttling.shared_cpu_map);
432 	device->driver_data = NULL;
433 	per_cpu(processors, pr->id) = NULL;
434  err_free_pr:
435 	kfree(pr);
436 	return result;
437 }
438 
439 #ifdef CONFIG_ACPI_HOTPLUG_CPU
440 /* --------------------------------------------------------------------------
441                                     Removal
442    -------------------------------------------------------------------------- */
443 
444 static void acpi_processor_remove(struct acpi_device *device)
445 {
446 	struct acpi_processor *pr;
447 
448 	if (!device || !acpi_driver_data(device))
449 		return;
450 
451 	pr = acpi_driver_data(device);
452 	if (pr->id >= nr_cpu_ids)
453 		goto out;
454 
455 	/*
456 	 * The only reason why we ever get here is CPU hot-removal.  The CPU is
457 	 * already offline and the ACPI device removal locking prevents it from
458 	 * being put back online at this point.
459 	 *
460 	 * Unbind the driver from the processor device and detach it from the
461 	 * ACPI companion object.
462 	 */
463 	device_release_driver(pr->dev);
464 	acpi_unbind_one(pr->dev);
465 
466 	/* Clean up. */
467 	per_cpu(processor_device_array, pr->id) = NULL;
468 	per_cpu(processors, pr->id) = NULL;
469 
470 	cpu_maps_update_begin();
471 	cpu_hotplug_begin();
472 
473 	/* Remove the CPU. */
474 	arch_unregister_cpu(pr->id);
475 	acpi_unmap_cpu(pr->id);
476 
477 	cpu_hotplug_done();
478 	cpu_maps_update_done();
479 
480 	try_offline_node(cpu_to_node(pr->id));
481 
482  out:
483 	free_cpumask_var(pr->throttling.shared_cpu_map);
484 	kfree(pr);
485 }
486 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
487 
488 #ifdef CONFIG_X86
489 static bool acpi_hwp_native_thermal_lvt_set;
490 static acpi_status __init acpi_hwp_native_thermal_lvt_osc(acpi_handle handle,
491 							  u32 lvl,
492 							  void *context,
493 							  void **rv)
494 {
495 	u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";
496 	u32 capbuf[2];
497 	struct acpi_osc_context osc_context = {
498 		.uuid_str = sb_uuid_str,
499 		.rev = 1,
500 		.cap.length = 8,
501 		.cap.pointer = capbuf,
502 	};
503 
504 	if (acpi_hwp_native_thermal_lvt_set)
505 		return AE_CTRL_TERMINATE;
506 
507 	capbuf[0] = 0x0000;
508 	capbuf[1] = 0x1000; /* set bit 12 */
509 
510 	if (ACPI_SUCCESS(acpi_run_osc(handle, &osc_context))) {
511 		if (osc_context.ret.pointer && osc_context.ret.length > 1) {
512 			u32 *capbuf_ret = osc_context.ret.pointer;
513 
514 			if (capbuf_ret[1] & 0x1000) {
515 				acpi_handle_info(handle,
516 					"_OSC native thermal LVT Acked\n");
517 				acpi_hwp_native_thermal_lvt_set = true;
518 			}
519 		}
520 		kfree(osc_context.ret.pointer);
521 	}
522 
523 	return AE_OK;
524 }
525 
526 void __init acpi_early_processor_osc(void)
527 {
528 	if (boot_cpu_has(X86_FEATURE_HWP)) {
529 		acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
530 				    ACPI_UINT32_MAX,
531 				    acpi_hwp_native_thermal_lvt_osc,
532 				    NULL, NULL, NULL);
533 		acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID,
534 				 acpi_hwp_native_thermal_lvt_osc,
535 				 NULL, NULL);
536 	}
537 }
538 #endif
539 
540 /*
541  * The following ACPI IDs are known to be suitable for representing as
542  * processor devices.
543  */
544 static const struct acpi_device_id processor_device_ids[] = {
545 
546 	{ ACPI_PROCESSOR_OBJECT_HID, },
547 	{ ACPI_PROCESSOR_DEVICE_HID, },
548 
549 	{ }
550 };
551 
552 static struct acpi_scan_handler processor_handler = {
553 	.ids = processor_device_ids,
554 	.attach = acpi_processor_add,
555 #ifdef CONFIG_ACPI_HOTPLUG_CPU
556 	.detach = acpi_processor_remove,
557 #endif
558 	.hotplug = {
559 		.enabled = true,
560 	},
561 };
562 
563 static int acpi_processor_container_attach(struct acpi_device *dev,
564 					   const struct acpi_device_id *id)
565 {
566 	return 1;
567 }
568 
569 static const struct acpi_device_id processor_container_ids[] = {
570 	{ ACPI_PROCESSOR_CONTAINER_HID, },
571 	{ }
572 };
573 
574 static struct acpi_scan_handler processor_container_handler = {
575 	.ids = processor_container_ids,
576 	.attach = acpi_processor_container_attach,
577 };
578 
579 /* The number of the unique processor IDs */
580 static int nr_unique_ids __initdata;
581 
582 /* The number of the duplicate processor IDs */
583 static int nr_duplicate_ids;
584 
585 /* Used to store the unique processor IDs */
586 static int unique_processor_ids[] __initdata = {
587 	[0 ... NR_CPUS - 1] = -1,
588 };
589 
590 /* Used to store the duplicate processor IDs */
591 static int duplicate_processor_ids[] = {
592 	[0 ... NR_CPUS - 1] = -1,
593 };
594 
595 static void __init processor_validated_ids_update(int proc_id)
596 {
597 	int i;
598 
599 	if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
600 		return;
601 
602 	/*
603 	 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
604 	 * already in the IDs, do nothing.
605 	 */
606 	for (i = 0; i < nr_duplicate_ids; i++) {
607 		if (duplicate_processor_ids[i] == proc_id)
608 			return;
609 	}
610 
611 	/*
612 	 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
613 	 * the IDs, put it in the duplicate IDs.
614 	 */
615 	for (i = 0; i < nr_unique_ids; i++) {
616 		if (unique_processor_ids[i] == proc_id) {
617 			duplicate_processor_ids[nr_duplicate_ids] = proc_id;
618 			nr_duplicate_ids++;
619 			return;
620 		}
621 	}
622 
623 	/*
624 	 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
625 	 */
626 	unique_processor_ids[nr_unique_ids] = proc_id;
627 	nr_unique_ids++;
628 }
629 
630 static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
631 						  u32 lvl,
632 						  void *context,
633 						  void **rv)
634 {
635 	acpi_status status;
636 	acpi_object_type acpi_type;
637 	unsigned long long uid;
638 	union acpi_object object = { 0 };
639 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
640 
641 	status = acpi_get_type(handle, &acpi_type);
642 	if (ACPI_FAILURE(status))
643 		return status;
644 
645 	switch (acpi_type) {
646 	case ACPI_TYPE_PROCESSOR:
647 		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
648 		if (ACPI_FAILURE(status))
649 			goto err;
650 		uid = object.processor.proc_id;
651 		break;
652 
653 	case ACPI_TYPE_DEVICE:
654 		status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
655 		if (ACPI_FAILURE(status))
656 			goto err;
657 		break;
658 	default:
659 		goto err;
660 	}
661 
662 	processor_validated_ids_update(uid);
663 	return AE_OK;
664 
665 err:
666 	/* Exit on error, but don't abort the namespace walk */
667 	acpi_handle_info(handle, "Invalid processor object\n");
668 	return AE_OK;
669 
670 }
671 
672 static void __init acpi_processor_check_duplicates(void)
673 {
674 	/* check the correctness for all processors in ACPI namespace */
675 	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
676 						ACPI_UINT32_MAX,
677 						acpi_processor_ids_walk,
678 						NULL, NULL, NULL);
679 	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
680 						NULL, NULL);
681 }
682 
683 bool acpi_duplicate_processor_id(int proc_id)
684 {
685 	int i;
686 
687 	/*
688 	 * compare the proc_id with duplicate IDs, if the proc_id is already
689 	 * in the duplicate IDs, return true, otherwise, return false.
690 	 */
691 	for (i = 0; i < nr_duplicate_ids; i++) {
692 		if (duplicate_processor_ids[i] == proc_id)
693 			return true;
694 	}
695 	return false;
696 }
697 
698 void __init acpi_processor_init(void)
699 {
700 	acpi_processor_check_duplicates();
701 	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
702 	acpi_scan_add_handler(&processor_container_handler);
703 }
704