xref: /linux/drivers/acpi/acpi_processor.c (revision f4fee216df7d28b87d1c9cc60bcebfecb51c1a05)
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 #define pr_fmt(fmt) "ACPI: " fmt
13 
14 #include <linux/acpi.h>
15 #include <linux/cpu.h>
16 #include <linux/device.h>
17 #include <linux/dmi.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/pci.h>
21 #include <linux/platform_device.h>
22 
23 #include <acpi/processor.h>
24 
25 #include <asm/cpu.h>
26 
27 #include <xen/xen.h>
28 
29 #include "internal.h"
30 
31 DEFINE_PER_CPU(struct acpi_processor *, processors);
32 EXPORT_PER_CPU_SYMBOL(processors);
33 
34 /* Errata Handling */
35 struct acpi_processor_errata errata __read_mostly;
36 EXPORT_SYMBOL_GPL(errata);
37 
38 static int acpi_processor_errata_piix4(struct pci_dev *dev)
39 {
40 	u8 value1 = 0;
41 	u8 value2 = 0;
42 
43 
44 	if (!dev)
45 		return -EINVAL;
46 
47 	/*
48 	 * Note that 'dev' references the PIIX4 ACPI Controller.
49 	 */
50 
51 	switch (dev->revision) {
52 	case 0:
53 		dev_dbg(&dev->dev, "Found PIIX4 A-step\n");
54 		break;
55 	case 1:
56 		dev_dbg(&dev->dev, "Found PIIX4 B-step\n");
57 		break;
58 	case 2:
59 		dev_dbg(&dev->dev, "Found PIIX4E\n");
60 		break;
61 	case 3:
62 		dev_dbg(&dev->dev, "Found PIIX4M\n");
63 		break;
64 	default:
65 		dev_dbg(&dev->dev, "Found unknown PIIX4\n");
66 		break;
67 	}
68 
69 	switch (dev->revision) {
70 
71 	case 0:		/* PIIX4 A-step */
72 	case 1:		/* PIIX4 B-step */
73 		/*
74 		 * See specification changes #13 ("Manual Throttle Duty Cycle")
75 		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
76 		 * erratum #5 ("STPCLK# Deassertion Time") from the January
77 		 * 2002 PIIX4 specification update.  Applies to only older
78 		 * PIIX4 models.
79 		 */
80 		errata.piix4.throttle = 1;
81 		fallthrough;
82 
83 	case 2:		/* PIIX4E */
84 	case 3:		/* PIIX4M */
85 		/*
86 		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
87 		 * Livelock") from the January 2002 PIIX4 specification update.
88 		 * Applies to all PIIX4 models.
89 		 */
90 
91 		/*
92 		 * BM-IDE
93 		 * ------
94 		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
95 		 * Status register address.  We'll use this later to read
96 		 * each IDE controller's DMA status to make sure we catch all
97 		 * DMA activity.
98 		 */
99 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
100 				     PCI_DEVICE_ID_INTEL_82371AB,
101 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
102 		if (dev) {
103 			errata.piix4.bmisx = pci_resource_start(dev, 4);
104 			pci_dev_put(dev);
105 		}
106 
107 		/*
108 		 * Type-F DMA
109 		 * ----------
110 		 * Find the PIIX4 ISA Controller and read the Motherboard
111 		 * DMA controller's status to see if Type-F (Fast) DMA mode
112 		 * is enabled (bit 7) on either channel.  Note that we'll
113 		 * disable C3 support if this is enabled, as some legacy
114 		 * devices won't operate well if fast DMA is disabled.
115 		 */
116 		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
117 				     PCI_DEVICE_ID_INTEL_82371AB_0,
118 				     PCI_ANY_ID, PCI_ANY_ID, NULL);
119 		if (dev) {
120 			pci_read_config_byte(dev, 0x76, &value1);
121 			pci_read_config_byte(dev, 0x77, &value2);
122 			if ((value1 & 0x80) || (value2 & 0x80))
123 				errata.piix4.fdma = 1;
124 			pci_dev_put(dev);
125 		}
126 
127 		break;
128 	}
129 
130 	if (errata.piix4.bmisx)
131 		dev_dbg(&dev->dev, "Bus master activity detection (BM-IDE) erratum enabled\n");
132 	if (errata.piix4.fdma)
133 		dev_dbg(&dev->dev, "Type-F DMA livelock erratum (C3 disabled)\n");
134 
135 	return 0;
136 }
137 
138 static int acpi_processor_errata(void)
139 {
140 	int result = 0;
141 	struct pci_dev *dev = NULL;
142 
143 	/*
144 	 * PIIX4
145 	 */
146 	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
147 			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
148 			     PCI_ANY_ID, NULL);
149 	if (dev) {
150 		result = acpi_processor_errata_piix4(dev);
151 		pci_dev_put(dev);
152 	}
153 
154 	return result;
155 }
156 
157 /* Create a platform device to represent a CPU frequency control mechanism. */
158 static void cpufreq_add_device(const char *name)
159 {
160 	struct platform_device *pdev;
161 
162 	pdev = platform_device_register_simple(name, PLATFORM_DEVID_NONE, NULL, 0);
163 	if (IS_ERR(pdev))
164 		pr_info("%s device creation failed: %pe\n", name, pdev);
165 }
166 
167 #ifdef CONFIG_X86
168 /* Check presence of Processor Clocking Control by searching for \_SB.PCCH. */
169 static void __init acpi_pcc_cpufreq_init(void)
170 {
171 	acpi_status status;
172 	acpi_handle handle;
173 
174 	status = acpi_get_handle(NULL, "\\_SB", &handle);
175 	if (ACPI_FAILURE(status))
176 		return;
177 
178 	if (acpi_has_method(handle, "PCCH"))
179 		cpufreq_add_device("pcc-cpufreq");
180 }
181 #else
182 static void __init acpi_pcc_cpufreq_init(void) {}
183 #endif /* CONFIG_X86 */
184 
185 /* Initialization */
186 #ifdef CONFIG_ACPI_HOTPLUG_CPU
187 static int acpi_processor_hotadd_init(struct acpi_processor *pr)
188 {
189 	unsigned long long sta;
190 	acpi_status status;
191 	int ret;
192 
193 	if (invalid_phys_cpuid(pr->phys_id))
194 		return -ENODEV;
195 
196 	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
197 	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
198 		return -ENODEV;
199 
200 	cpu_maps_update_begin();
201 	cpus_write_lock();
202 
203 	ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);
204 	if (ret)
205 		goto out;
206 
207 	ret = arch_register_cpu(pr->id);
208 	if (ret) {
209 		acpi_unmap_cpu(pr->id);
210 		goto out;
211 	}
212 
213 	/*
214 	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
215 	 * to delay cpu_idle/throttling initialization and do it when the CPU
216 	 * gets online for the first time.
217 	 */
218 	pr_info("CPU%d has been hot-added\n", pr->id);
219 	pr->flags.need_hotplug_init = 1;
220 
221 out:
222 	cpus_write_unlock();
223 	cpu_maps_update_done();
224 	return ret;
225 }
226 #else
227 static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
228 {
229 	return -ENODEV;
230 }
231 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
232 
233 static int acpi_processor_get_info(struct acpi_device *device)
234 {
235 	union acpi_object object = { 0 };
236 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
237 	struct acpi_processor *pr = acpi_driver_data(device);
238 	int device_declaration = 0;
239 	acpi_status status = AE_OK;
240 	static int cpu0_initialized;
241 	unsigned long long value;
242 
243 	acpi_processor_errata();
244 
245 	/*
246 	 * Check to see if we have bus mastering arbitration control.  This
247 	 * is required for proper C3 usage (to maintain cache coherency).
248 	 */
249 	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
250 		pr->flags.bm_control = 1;
251 		dev_dbg(&device->dev, "Bus mastering arbitration control present\n");
252 	} else
253 		dev_dbg(&device->dev, "No bus mastering arbitration control\n");
254 
255 	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
256 		/* Declared with "Processor" statement; match ProcessorID */
257 		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
258 		if (ACPI_FAILURE(status)) {
259 			dev_err(&device->dev,
260 				"Failed to evaluate processor object (0x%x)\n",
261 				status);
262 			return -ENODEV;
263 		}
264 
265 		pr->acpi_id = object.processor.proc_id;
266 	} else {
267 		/*
268 		 * Declared with "Device" statement; match _UID.
269 		 */
270 		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
271 						NULL, &value);
272 		if (ACPI_FAILURE(status)) {
273 			dev_err(&device->dev,
274 				"Failed to evaluate processor _UID (0x%x)\n",
275 				status);
276 			return -ENODEV;
277 		}
278 		device_declaration = 1;
279 		pr->acpi_id = value;
280 	}
281 
282 	if (acpi_duplicate_processor_id(pr->acpi_id)) {
283 		if (pr->acpi_id == 0xff)
284 			dev_info_once(&device->dev,
285 				"Entry not well-defined, consider updating BIOS\n");
286 		else
287 			dev_err(&device->dev,
288 				"Failed to get unique processor _UID (0x%x)\n",
289 				pr->acpi_id);
290 		return -ENODEV;
291 	}
292 
293 	pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
294 					pr->acpi_id);
295 	if (invalid_phys_cpuid(pr->phys_id))
296 		dev_dbg(&device->dev, "Failed to get CPU physical ID.\n");
297 
298 	pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);
299 	if (!cpu0_initialized) {
300 		cpu0_initialized = 1;
301 		/*
302 		 * Handle UP system running SMP kernel, with no CPU
303 		 * entry in MADT
304 		 */
305 		if (!acpi_has_cpu_in_madt() && invalid_logical_cpuid(pr->id) &&
306 		    (num_online_cpus() == 1))
307 			pr->id = 0;
308 		/*
309 		 * Check availability of Processor Performance Control by
310 		 * looking at the presence of the _PCT object under the first
311 		 * processor definition.
312 		 */
313 		if (acpi_has_method(pr->handle, "_PCT"))
314 			cpufreq_add_device("acpi-cpufreq");
315 	}
316 
317 	/*
318 	 *  Extra Processor objects may be enumerated on MP systems with
319 	 *  less than the max # of CPUs. They should be ignored _iff
320 	 *  they are physically not present.
321 	 *
322 	 *  NOTE: Even if the processor has a cpuid, it may not be present
323 	 *  because cpuid <-> apicid mapping is persistent now.
324 	 */
325 	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
326 		int ret = acpi_processor_hotadd_init(pr);
327 
328 		if (ret)
329 			return ret;
330 	}
331 
332 	/*
333 	 * On some boxes several processors use the same processor bus id.
334 	 * But they are located in different scope. For example:
335 	 * \_SB.SCK0.CPU0
336 	 * \_SB.SCK1.CPU0
337 	 * Rename the processor device bus id. And the new bus id will be
338 	 * generated as the following format:
339 	 * CPU+CPU ID.
340 	 */
341 	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
342 	dev_dbg(&device->dev, "Processor [%d:%d]\n", pr->id, pr->acpi_id);
343 
344 	if (!object.processor.pblk_address)
345 		dev_dbg(&device->dev, "No PBLK (NULL address)\n");
346 	else if (object.processor.pblk_length != 6)
347 		dev_err(&device->dev, "Invalid PBLK length [%d]\n",
348 			    object.processor.pblk_length);
349 	else {
350 		pr->throttling.address = object.processor.pblk_address;
351 		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
352 		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
353 
354 		pr->pblk = object.processor.pblk_address;
355 	}
356 
357 	/*
358 	 * If ACPI describes a slot number for this CPU, we can use it to
359 	 * ensure we get the right value in the "physical id" field
360 	 * of /proc/cpuinfo
361 	 */
362 	status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
363 	if (ACPI_SUCCESS(status))
364 		arch_fix_phys_package_id(pr->id, value);
365 
366 	return 0;
367 }
368 
369 /*
370  * Do not put anything in here which needs the core to be online.
371  * For example MSR access or setting up things which check for cpuinfo_x86
372  * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
373  * Such things have to be put in and set up by the processor driver's .probe().
374  */
375 static DEFINE_PER_CPU(void *, processor_device_array);
376 
377 static int acpi_processor_add(struct acpi_device *device,
378 					const struct acpi_device_id *id)
379 {
380 	struct acpi_processor *pr;
381 	struct device *dev;
382 	int result = 0;
383 
384 	if (!acpi_device_is_enabled(device))
385 		return -ENODEV;
386 
387 	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
388 	if (!pr)
389 		return -ENOMEM;
390 
391 	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
392 		result = -ENOMEM;
393 		goto err_free_pr;
394 	}
395 
396 	pr->handle = device->handle;
397 	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
398 	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
399 	device->driver_data = pr;
400 
401 	result = acpi_processor_get_info(device);
402 	if (result) /* Processor is not physically present or unavailable */
403 		return 0;
404 
405 	BUG_ON(pr->id >= nr_cpu_ids);
406 
407 	/*
408 	 * Buggy BIOS check.
409 	 * ACPI id of processors can be reported wrongly by the BIOS.
410 	 * Don't trust it blindly
411 	 */
412 	if (per_cpu(processor_device_array, pr->id) != NULL &&
413 	    per_cpu(processor_device_array, pr->id) != device) {
414 		dev_warn(&device->dev,
415 			"BIOS reported wrong ACPI id %d for the processor\n",
416 			pr->id);
417 		/* Give up, but do not abort the namespace scan. */
418 		goto err;
419 	}
420 	/*
421 	 * processor_device_array is not cleared on errors to allow buggy BIOS
422 	 * checks.
423 	 */
424 	per_cpu(processor_device_array, pr->id) = device;
425 	per_cpu(processors, pr->id) = pr;
426 
427 	dev = get_cpu_device(pr->id);
428 	if (!dev) {
429 		result = -ENODEV;
430 		goto err;
431 	}
432 
433 	result = acpi_bind_one(dev, device);
434 	if (result)
435 		goto err;
436 
437 	pr->dev = dev;
438 
439 	/* Trigger the processor driver's .probe() if present. */
440 	if (device_attach(dev) >= 0)
441 		return 1;
442 
443 	dev_err(dev, "Processor driver could not be attached\n");
444 	acpi_unbind_one(dev);
445 
446  err:
447 	free_cpumask_var(pr->throttling.shared_cpu_map);
448 	device->driver_data = NULL;
449 	per_cpu(processors, pr->id) = NULL;
450  err_free_pr:
451 	kfree(pr);
452 	return result;
453 }
454 
455 #ifdef CONFIG_ACPI_HOTPLUG_CPU
456 /* Removal */
457 static void acpi_processor_remove(struct acpi_device *device)
458 {
459 	struct acpi_processor *pr;
460 
461 	if (!device || !acpi_driver_data(device))
462 		return;
463 
464 	pr = acpi_driver_data(device);
465 	if (pr->id >= nr_cpu_ids)
466 		goto out;
467 
468 	/*
469 	 * The only reason why we ever get here is CPU hot-removal.  The CPU is
470 	 * already offline and the ACPI device removal locking prevents it from
471 	 * being put back online at this point.
472 	 *
473 	 * Unbind the driver from the processor device and detach it from the
474 	 * ACPI companion object.
475 	 */
476 	device_release_driver(pr->dev);
477 	acpi_unbind_one(pr->dev);
478 
479 	/* Clean up. */
480 	per_cpu(processor_device_array, pr->id) = NULL;
481 	per_cpu(processors, pr->id) = NULL;
482 
483 	cpu_maps_update_begin();
484 	cpus_write_lock();
485 
486 	/* Remove the CPU. */
487 	arch_unregister_cpu(pr->id);
488 	acpi_unmap_cpu(pr->id);
489 
490 	cpus_write_unlock();
491 	cpu_maps_update_done();
492 
493 	try_offline_node(cpu_to_node(pr->id));
494 
495  out:
496 	free_cpumask_var(pr->throttling.shared_cpu_map);
497 	kfree(pr);
498 }
499 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
500 
501 #ifdef CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC
502 bool __init processor_physically_present(acpi_handle handle)
503 {
504 	int cpuid, type;
505 	u32 acpi_id;
506 	acpi_status status;
507 	acpi_object_type acpi_type;
508 	unsigned long long tmp;
509 	union acpi_object object = {};
510 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
511 
512 	status = acpi_get_type(handle, &acpi_type);
513 	if (ACPI_FAILURE(status))
514 		return false;
515 
516 	switch (acpi_type) {
517 	case ACPI_TYPE_PROCESSOR:
518 		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
519 		if (ACPI_FAILURE(status))
520 			return false;
521 		acpi_id = object.processor.proc_id;
522 		break;
523 	case ACPI_TYPE_DEVICE:
524 		status = acpi_evaluate_integer(handle, METHOD_NAME__UID,
525 					       NULL, &tmp);
526 		if (ACPI_FAILURE(status))
527 			return false;
528 		acpi_id = tmp;
529 		break;
530 	default:
531 		return false;
532 	}
533 
534 	if (xen_initial_domain())
535 		/*
536 		 * When running as a Xen dom0 the number of processors Linux
537 		 * sees can be different from the real number of processors on
538 		 * the system, and we still need to execute _PDC or _OSC for
539 		 * all of them.
540 		 */
541 		return xen_processor_present(acpi_id);
542 
543 	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
544 	cpuid = acpi_get_cpuid(handle, type, acpi_id);
545 
546 	return !invalid_logical_cpuid(cpuid);
547 }
548 
549 /* vendor specific UUID indicating an Intel platform */
550 static u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";
551 
552 static acpi_status __init acpi_processor_osc(acpi_handle handle, u32 lvl,
553 					     void *context, void **rv)
554 {
555 	u32 capbuf[2] = {};
556 	struct acpi_osc_context osc_context = {
557 		.uuid_str = sb_uuid_str,
558 		.rev = 1,
559 		.cap.length = 8,
560 		.cap.pointer = capbuf,
561 	};
562 	acpi_status status;
563 
564 	if (!processor_physically_present(handle))
565 		return AE_OK;
566 
567 	arch_acpi_set_proc_cap_bits(&capbuf[OSC_SUPPORT_DWORD]);
568 
569 	status = acpi_run_osc(handle, &osc_context);
570 	if (ACPI_FAILURE(status))
571 		return status;
572 
573 	kfree(osc_context.ret.pointer);
574 
575 	return AE_OK;
576 }
577 
578 static bool __init acpi_early_processor_osc(void)
579 {
580 	acpi_status status;
581 
582 	acpi_proc_quirk_mwait_check();
583 
584 	status = acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
585 				     ACPI_UINT32_MAX, acpi_processor_osc, NULL,
586 				     NULL, NULL);
587 	if (ACPI_FAILURE(status))
588 		return false;
589 
590 	status = acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_osc,
591 				  NULL, NULL);
592 	if (ACPI_FAILURE(status))
593 		return false;
594 
595 	return true;
596 }
597 
598 void __init acpi_early_processor_control_setup(void)
599 {
600 	if (acpi_early_processor_osc()) {
601 		pr_info("_OSC evaluated successfully for all CPUs\n");
602 	} else {
603 		pr_info("_OSC evaluation for CPUs failed, trying _PDC\n");
604 		acpi_early_processor_set_pdc();
605 	}
606 }
607 #endif
608 
609 /*
610  * The following ACPI IDs are known to be suitable for representing as
611  * processor devices.
612  */
613 static const struct acpi_device_id processor_device_ids[] = {
614 
615 	{ ACPI_PROCESSOR_OBJECT_HID, },
616 	{ ACPI_PROCESSOR_DEVICE_HID, },
617 
618 	{ }
619 };
620 
621 static struct acpi_scan_handler processor_handler = {
622 	.ids = processor_device_ids,
623 	.attach = acpi_processor_add,
624 #ifdef CONFIG_ACPI_HOTPLUG_CPU
625 	.detach = acpi_processor_remove,
626 #endif
627 	.hotplug = {
628 		.enabled = true,
629 	},
630 };
631 
632 static int acpi_processor_container_attach(struct acpi_device *dev,
633 					   const struct acpi_device_id *id)
634 {
635 	return 1;
636 }
637 
638 static const struct acpi_device_id processor_container_ids[] = {
639 	{ ACPI_PROCESSOR_CONTAINER_HID, },
640 	{ }
641 };
642 
643 static struct acpi_scan_handler processor_container_handler = {
644 	.ids = processor_container_ids,
645 	.attach = acpi_processor_container_attach,
646 };
647 
648 /* The number of the unique processor IDs */
649 static int nr_unique_ids __initdata;
650 
651 /* The number of the duplicate processor IDs */
652 static int nr_duplicate_ids;
653 
654 /* Used to store the unique processor IDs */
655 static int unique_processor_ids[] __initdata = {
656 	[0 ... NR_CPUS - 1] = -1,
657 };
658 
659 /* Used to store the duplicate processor IDs */
660 static int duplicate_processor_ids[] = {
661 	[0 ... NR_CPUS - 1] = -1,
662 };
663 
664 static void __init processor_validated_ids_update(int proc_id)
665 {
666 	int i;
667 
668 	if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
669 		return;
670 
671 	/*
672 	 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
673 	 * already in the IDs, do nothing.
674 	 */
675 	for (i = 0; i < nr_duplicate_ids; i++) {
676 		if (duplicate_processor_ids[i] == proc_id)
677 			return;
678 	}
679 
680 	/*
681 	 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
682 	 * the IDs, put it in the duplicate IDs.
683 	 */
684 	for (i = 0; i < nr_unique_ids; i++) {
685 		if (unique_processor_ids[i] == proc_id) {
686 			duplicate_processor_ids[nr_duplicate_ids] = proc_id;
687 			nr_duplicate_ids++;
688 			return;
689 		}
690 	}
691 
692 	/*
693 	 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
694 	 */
695 	unique_processor_ids[nr_unique_ids] = proc_id;
696 	nr_unique_ids++;
697 }
698 
699 static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
700 						  u32 lvl,
701 						  void *context,
702 						  void **rv)
703 {
704 	acpi_status status;
705 	acpi_object_type acpi_type;
706 	unsigned long long uid;
707 	union acpi_object object = { 0 };
708 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
709 
710 	status = acpi_get_type(handle, &acpi_type);
711 	if (ACPI_FAILURE(status))
712 		return status;
713 
714 	switch (acpi_type) {
715 	case ACPI_TYPE_PROCESSOR:
716 		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
717 		if (ACPI_FAILURE(status))
718 			goto err;
719 		uid = object.processor.proc_id;
720 		break;
721 
722 	case ACPI_TYPE_DEVICE:
723 		status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
724 		if (ACPI_FAILURE(status))
725 			goto err;
726 		break;
727 	default:
728 		goto err;
729 	}
730 
731 	processor_validated_ids_update(uid);
732 	return AE_OK;
733 
734 err:
735 	/* Exit on error, but don't abort the namespace walk */
736 	acpi_handle_info(handle, "Invalid processor object\n");
737 	return AE_OK;
738 
739 }
740 
741 static void __init acpi_processor_check_duplicates(void)
742 {
743 	/* check the correctness for all processors in ACPI namespace */
744 	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
745 						ACPI_UINT32_MAX,
746 						acpi_processor_ids_walk,
747 						NULL, NULL, NULL);
748 	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
749 						NULL, NULL);
750 }
751 
752 bool acpi_duplicate_processor_id(int proc_id)
753 {
754 	int i;
755 
756 	/*
757 	 * compare the proc_id with duplicate IDs, if the proc_id is already
758 	 * in the duplicate IDs, return true, otherwise, return false.
759 	 */
760 	for (i = 0; i < nr_duplicate_ids; i++) {
761 		if (duplicate_processor_ids[i] == proc_id)
762 			return true;
763 	}
764 	return false;
765 }
766 
767 void __init acpi_processor_init(void)
768 {
769 	acpi_processor_check_duplicates();
770 	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
771 	acpi_scan_add_handler(&processor_container_handler);
772 	acpi_pcc_cpufreq_init();
773 }
774 
775 #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
776 /**
777  * acpi_processor_claim_cst_control - Request _CST control from the platform.
778  */
779 bool acpi_processor_claim_cst_control(void)
780 {
781 	static bool cst_control_claimed;
782 	acpi_status status;
783 
784 	if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
785 		return true;
786 
787 	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
788 				    acpi_gbl_FADT.cst_control, 8);
789 	if (ACPI_FAILURE(status)) {
790 		pr_warn("ACPI: Failed to claim processor _CST control\n");
791 		return false;
792 	}
793 
794 	cst_control_claimed = true;
795 	return true;
796 }
797 EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);
798 
799 /**
800  * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
801  * @handle: ACPI handle of the processor object containing the _CST.
802  * @cpu: The numeric ID of the target CPU.
803  * @info: Object write the C-states information into.
804  *
805  * Extract the C-state information for the given CPU from the output of the _CST
806  * control method under the corresponding ACPI processor object (or processor
807  * device object) and populate @info with it.
808  *
809  * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
810  * acpi_processor_ffh_cstate_probe() to verify them and update the
811  * cpu_cstate_entry data for @cpu.
812  */
813 int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
814 				struct acpi_processor_power *info)
815 {
816 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
817 	union acpi_object *cst;
818 	acpi_status status;
819 	u64 count;
820 	int last_index = 0;
821 	int i, ret = 0;
822 
823 	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
824 	if (ACPI_FAILURE(status)) {
825 		acpi_handle_debug(handle, "No _CST\n");
826 		return -ENODEV;
827 	}
828 
829 	cst = buffer.pointer;
830 
831 	/* There must be at least 2 elements. */
832 	if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
833 		acpi_handle_warn(handle, "Invalid _CST output\n");
834 		ret = -EFAULT;
835 		goto end;
836 	}
837 
838 	count = cst->package.elements[0].integer.value;
839 
840 	/* Validate the number of C-states. */
841 	if (count < 1 || count != cst->package.count - 1) {
842 		acpi_handle_warn(handle, "Inconsistent _CST data\n");
843 		ret = -EFAULT;
844 		goto end;
845 	}
846 
847 	for (i = 1; i <= count; i++) {
848 		union acpi_object *element;
849 		union acpi_object *obj;
850 		struct acpi_power_register *reg;
851 		struct acpi_processor_cx cx;
852 
853 		/*
854 		 * If there is not enough space for all C-states, skip the
855 		 * excess ones and log a warning.
856 		 */
857 		if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
858 			acpi_handle_warn(handle,
859 					 "No room for more idle states (limit: %d)\n",
860 					 ACPI_PROCESSOR_MAX_POWER - 1);
861 			break;
862 		}
863 
864 		memset(&cx, 0, sizeof(cx));
865 
866 		element = &cst->package.elements[i];
867 		if (element->type != ACPI_TYPE_PACKAGE) {
868 			acpi_handle_info(handle, "_CST C%d type(%x) is not package, skip...\n",
869 					 i, element->type);
870 			continue;
871 		}
872 
873 		if (element->package.count != 4) {
874 			acpi_handle_info(handle, "_CST C%d package count(%d) is not 4, skip...\n",
875 					 i, element->package.count);
876 			continue;
877 		}
878 
879 		obj = &element->package.elements[0];
880 
881 		if (obj->type != ACPI_TYPE_BUFFER) {
882 			acpi_handle_info(handle, "_CST C%d package element[0] type(%x) is not buffer, skip...\n",
883 					 i, obj->type);
884 			continue;
885 		}
886 
887 		reg = (struct acpi_power_register *)obj->buffer.pointer;
888 
889 		obj = &element->package.elements[1];
890 		if (obj->type != ACPI_TYPE_INTEGER) {
891 			acpi_handle_info(handle, "_CST C[%d] package element[1] type(%x) is not integer, skip...\n",
892 					 i, obj->type);
893 			continue;
894 		}
895 
896 		cx.type = obj->integer.value;
897 		/*
898 		 * There are known cases in which the _CST output does not
899 		 * contain C1, so if the type of the first state found is not
900 		 * C1, leave an empty slot for C1 to be filled in later.
901 		 */
902 		if (i == 1 && cx.type != ACPI_STATE_C1)
903 			last_index = 1;
904 
905 		cx.address = reg->address;
906 		cx.index = last_index + 1;
907 
908 		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
909 			if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
910 				/*
911 				 * In the majority of cases _CST describes C1 as
912 				 * a FIXED_HARDWARE C-state, but if the command
913 				 * line forbids using MWAIT, use CSTATE_HALT for
914 				 * C1 regardless.
915 				 */
916 				if (cx.type == ACPI_STATE_C1 &&
917 				    boot_option_idle_override == IDLE_NOMWAIT) {
918 					cx.entry_method = ACPI_CSTATE_HALT;
919 					snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
920 				} else {
921 					cx.entry_method = ACPI_CSTATE_FFH;
922 				}
923 			} else if (cx.type == ACPI_STATE_C1) {
924 				/*
925 				 * In the special case of C1, FIXED_HARDWARE can
926 				 * be handled by executing the HLT instruction.
927 				 */
928 				cx.entry_method = ACPI_CSTATE_HALT;
929 				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
930 			} else {
931 				acpi_handle_info(handle, "_CST C%d declares FIXED_HARDWARE C-state but not supported in hardware, skip...\n",
932 						 i);
933 				continue;
934 			}
935 		} else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
936 			cx.entry_method = ACPI_CSTATE_SYSTEMIO;
937 			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
938 				 cx.address);
939 		} else {
940 			acpi_handle_info(handle, "_CST C%d space_id(%x) neither FIXED_HARDWARE nor SYSTEM_IO, skip...\n",
941 					 i, reg->space_id);
942 			continue;
943 		}
944 
945 		if (cx.type == ACPI_STATE_C1)
946 			cx.valid = 1;
947 
948 		obj = &element->package.elements[2];
949 		if (obj->type != ACPI_TYPE_INTEGER) {
950 			acpi_handle_info(handle, "_CST C%d package element[2] type(%x) not integer, skip...\n",
951 					 i, obj->type);
952 			continue;
953 		}
954 
955 		cx.latency = obj->integer.value;
956 
957 		obj = &element->package.elements[3];
958 		if (obj->type != ACPI_TYPE_INTEGER) {
959 			acpi_handle_info(handle, "_CST C%d package element[3] type(%x) not integer, skip...\n",
960 					 i, obj->type);
961 			continue;
962 		}
963 
964 		memcpy(&info->states[++last_index], &cx, sizeof(cx));
965 	}
966 
967 	acpi_handle_info(handle, "Found %d idle states\n", last_index);
968 
969 	info->count = last_index;
970 
971 end:
972 	kfree(buffer.pointer);
973 
974 	return ret;
975 }
976 EXPORT_SYMBOL_GPL(acpi_processor_evaluate_cst);
977 #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
978