1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2012 by Oracle Inc
4  * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
5  *
6  * This code borrows ideas from https://lkml.org/lkml/2011/11/30/249
7  * so many thanks go to Kevin Tian <kevin.tian@intel.com>
8  * and Yu Ke <ke.yu@intel.com>.
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/cpumask.h>
14 #include <linux/cpufreq.h>
15 #include <linux/freezer.h>
16 #include <linux/kernel.h>
17 #include <linux/kthread.h>
18 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/types.h>
21 #include <linux/syscore_ops.h>
22 #include <linux/acpi.h>
23 #include <acpi/processor.h>
24 #include <xen/xen.h>
25 #include <xen/interface/platform.h>
26 #include <asm/xen/hypercall.h>
27 
28 static int no_hypercall;
29 MODULE_PARM_DESC(off, "Inhibit the hypercall.");
30 module_param_named(off, no_hypercall, int, 0400);
31 
32 /*
33  * Note: Do not convert the acpi_id* below to cpumask_var_t or use cpumask_bit
34  * - as those shrink to nr_cpu_bits (which is dependent on possible_cpu), which
35  * can be less than what we want to put in. Instead use the 'nr_acpi_bits'
36  * which is dynamically computed based on the MADT or x2APIC table.
37  */
38 static unsigned int nr_acpi_bits;
39 /* Mutex to protect the acpi_ids_done - for CPU hotplug use. */
40 static DEFINE_MUTEX(acpi_ids_mutex);
41 /* Which ACPI ID we have processed from 'struct acpi_processor'. */
42 static unsigned long *acpi_ids_done;
43 /* Which ACPI ID exist in the SSDT/DSDT processor definitions. */
44 static unsigned long *acpi_id_present;
45 /* And if there is an _CST definition (or a PBLK) for the ACPI IDs */
46 static unsigned long *acpi_id_cst_present;
47 /* Which ACPI P-State dependencies for a enumerated processor */
48 static struct acpi_psd_package *acpi_psd;
49 
50 static int push_cxx_to_hypervisor(struct acpi_processor *_pr)
51 {
52 	struct xen_platform_op op = {
53 		.cmd			= XENPF_set_processor_pminfo,
54 		.interface_version	= XENPF_INTERFACE_VERSION,
55 		.u.set_pminfo.id	= _pr->acpi_id,
56 		.u.set_pminfo.type	= XEN_PM_CX,
57 	};
58 	struct xen_processor_cx *dst_cx, *dst_cx_states = NULL;
59 	struct acpi_processor_cx *cx;
60 	unsigned int i, ok;
61 	int ret = 0;
62 
63 	dst_cx_states = kcalloc(_pr->power.count,
64 				sizeof(struct xen_processor_cx), GFP_KERNEL);
65 	if (!dst_cx_states)
66 		return -ENOMEM;
67 
68 	for (ok = 0, i = 1; i <= _pr->power.count; i++) {
69 		cx = &_pr->power.states[i];
70 		if (!cx->valid)
71 			continue;
72 
73 		dst_cx = &(dst_cx_states[ok++]);
74 
75 		dst_cx->reg.space_id = ACPI_ADR_SPACE_SYSTEM_IO;
76 		if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
77 			dst_cx->reg.bit_width = 8;
78 			dst_cx->reg.bit_offset = 0;
79 			dst_cx->reg.access_size = 1;
80 		} else {
81 			dst_cx->reg.space_id = ACPI_ADR_SPACE_FIXED_HARDWARE;
82 			if (cx->entry_method == ACPI_CSTATE_FFH) {
83 				/* NATIVE_CSTATE_BEYOND_HALT */
84 				dst_cx->reg.bit_offset = 2;
85 				dst_cx->reg.bit_width = 1; /* VENDOR_INTEL */
86 			}
87 			dst_cx->reg.access_size = 0;
88 		}
89 		dst_cx->reg.address = cx->address;
90 
91 		dst_cx->type = cx->type;
92 		dst_cx->latency = cx->latency;
93 
94 		dst_cx->dpcnt = 0;
95 		set_xen_guest_handle(dst_cx->dp, NULL);
96 	}
97 	if (!ok) {
98 		pr_debug("No _Cx for ACPI CPU %u\n", _pr->acpi_id);
99 		kfree(dst_cx_states);
100 		return -EINVAL;
101 	}
102 	op.u.set_pminfo.power.count = ok;
103 	op.u.set_pminfo.power.flags.bm_control = _pr->flags.bm_control;
104 	op.u.set_pminfo.power.flags.bm_check = _pr->flags.bm_check;
105 	op.u.set_pminfo.power.flags.has_cst = _pr->flags.has_cst;
106 	op.u.set_pminfo.power.flags.power_setup_done =
107 		_pr->flags.power_setup_done;
108 
109 	set_xen_guest_handle(op.u.set_pminfo.power.states, dst_cx_states);
110 
111 	if (!no_hypercall)
112 		ret = HYPERVISOR_platform_op(&op);
113 
114 	if (!ret) {
115 		pr_debug("ACPI CPU%u - C-states uploaded.\n", _pr->acpi_id);
116 		for (i = 1; i <= _pr->power.count; i++) {
117 			cx = &_pr->power.states[i];
118 			if (!cx->valid)
119 				continue;
120 			pr_debug("     C%d: %s %d uS\n",
121 				 cx->type, cx->desc, (u32)cx->latency);
122 		}
123 	} else if ((ret != -EINVAL) && (ret != -ENOSYS))
124 		/* EINVAL means the ACPI ID is incorrect - meaning the ACPI
125 		 * table is referencing a non-existing CPU - which can happen
126 		 * with broken ACPI tables. */
127 		pr_err("(CX): Hypervisor error (%d) for ACPI CPU%u\n",
128 		       ret, _pr->acpi_id);
129 
130 	kfree(dst_cx_states);
131 
132 	return ret;
133 }
134 static struct xen_processor_px *
135 xen_copy_pss_data(struct acpi_processor *_pr,
136 		  struct xen_processor_performance *dst_perf)
137 {
138 	struct xen_processor_px *dst_states = NULL;
139 	unsigned int i;
140 
141 	BUILD_BUG_ON(sizeof(struct xen_processor_px) !=
142 		     sizeof(struct acpi_processor_px));
143 
144 	dst_states = kcalloc(_pr->performance->state_count,
145 			     sizeof(struct xen_processor_px), GFP_KERNEL);
146 	if (!dst_states)
147 		return ERR_PTR(-ENOMEM);
148 
149 	dst_perf->state_count = _pr->performance->state_count;
150 	for (i = 0; i < _pr->performance->state_count; i++) {
151 		/* Fortunatly for us, they are both the same size */
152 		memcpy(&(dst_states[i]), &(_pr->performance->states[i]),
153 		       sizeof(struct acpi_processor_px));
154 	}
155 	return dst_states;
156 }
157 static int xen_copy_psd_data(struct acpi_processor *_pr,
158 			     struct xen_processor_performance *dst)
159 {
160 	struct acpi_psd_package *pdomain;
161 
162 	BUILD_BUG_ON(sizeof(struct xen_psd_package) !=
163 		     sizeof(struct acpi_psd_package));
164 
165 	/* This information is enumerated only if acpi_processor_preregister_performance
166 	 * has been called.
167 	 */
168 	dst->shared_type = _pr->performance->shared_type;
169 
170 	pdomain = &(_pr->performance->domain_info);
171 
172 	/* 'acpi_processor_preregister_performance' does not parse if the
173 	 * num_processors <= 1, but Xen still requires it. Do it manually here.
174 	 */
175 	if (pdomain->num_processors <= 1) {
176 		if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
177 			dst->shared_type = CPUFREQ_SHARED_TYPE_ALL;
178 		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
179 			dst->shared_type = CPUFREQ_SHARED_TYPE_HW;
180 		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
181 			dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;
182 
183 	}
184 	memcpy(&(dst->domain_info), pdomain, sizeof(struct acpi_psd_package));
185 	return 0;
186 }
187 static int xen_copy_pct_data(struct acpi_pct_register *pct,
188 			     struct xen_pct_register *dst_pct)
189 {
190 	/* It would be nice if you could just do 'memcpy(pct, dst_pct') but
191 	 * sadly the Xen structure did not have the proper padding so the
192 	 * descriptor field takes two (dst_pct) bytes instead of one (pct).
193 	 */
194 	dst_pct->descriptor = pct->descriptor;
195 	dst_pct->length = pct->length;
196 	dst_pct->space_id = pct->space_id;
197 	dst_pct->bit_width = pct->bit_width;
198 	dst_pct->bit_offset = pct->bit_offset;
199 	dst_pct->reserved = pct->reserved;
200 	dst_pct->address = pct->address;
201 	return 0;
202 }
203 static int push_pxx_to_hypervisor(struct acpi_processor *_pr)
204 {
205 	int ret = 0;
206 	struct xen_platform_op op = {
207 		.cmd			= XENPF_set_processor_pminfo,
208 		.interface_version	= XENPF_INTERFACE_VERSION,
209 		.u.set_pminfo.id	= _pr->acpi_id,
210 		.u.set_pminfo.type	= XEN_PM_PX,
211 	};
212 	struct xen_processor_performance *dst_perf;
213 	struct xen_processor_px *dst_states = NULL;
214 
215 	dst_perf = &op.u.set_pminfo.perf;
216 
217 	dst_perf->platform_limit = _pr->performance_platform_limit;
218 	dst_perf->flags |= XEN_PX_PPC;
219 	xen_copy_pct_data(&(_pr->performance->control_register),
220 			  &dst_perf->control_register);
221 	xen_copy_pct_data(&(_pr->performance->status_register),
222 			  &dst_perf->status_register);
223 	dst_perf->flags |= XEN_PX_PCT;
224 	dst_states = xen_copy_pss_data(_pr, dst_perf);
225 	if (!IS_ERR_OR_NULL(dst_states)) {
226 		set_xen_guest_handle(dst_perf->states, dst_states);
227 		dst_perf->flags |= XEN_PX_PSS;
228 	}
229 	if (!xen_copy_psd_data(_pr, dst_perf))
230 		dst_perf->flags |= XEN_PX_PSD;
231 
232 	if (dst_perf->flags != (XEN_PX_PSD | XEN_PX_PSS | XEN_PX_PCT | XEN_PX_PPC)) {
233 		pr_warn("ACPI CPU%u missing some P-state data (%x), skipping\n",
234 			_pr->acpi_id, dst_perf->flags);
235 		ret = -ENODEV;
236 		goto err_free;
237 	}
238 
239 	if (!no_hypercall)
240 		ret = HYPERVISOR_platform_op(&op);
241 
242 	if (!ret) {
243 		struct acpi_processor_performance *perf;
244 		unsigned int i;
245 
246 		perf = _pr->performance;
247 		pr_debug("ACPI CPU%u - P-states uploaded.\n", _pr->acpi_id);
248 		for (i = 0; i < perf->state_count; i++) {
249 			pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
250 			(i == perf->state ? '*' : ' '), i,
251 			(u32) perf->states[i].core_frequency,
252 			(u32) perf->states[i].power,
253 			(u32) perf->states[i].transition_latency);
254 		}
255 	} else if ((ret != -EINVAL) && (ret != -ENOSYS))
256 		/* EINVAL means the ACPI ID is incorrect - meaning the ACPI
257 		 * table is referencing a non-existing CPU - which can happen
258 		 * with broken ACPI tables. */
259 		pr_warn("(_PXX): Hypervisor error (%d) for ACPI CPU%u\n",
260 			ret, _pr->acpi_id);
261 err_free:
262 	if (!IS_ERR_OR_NULL(dst_states))
263 		kfree(dst_states);
264 
265 	return ret;
266 }
267 static int upload_pm_data(struct acpi_processor *_pr)
268 {
269 	int err = 0;
270 
271 	mutex_lock(&acpi_ids_mutex);
272 	if (__test_and_set_bit(_pr->acpi_id, acpi_ids_done)) {
273 		mutex_unlock(&acpi_ids_mutex);
274 		return -EBUSY;
275 	}
276 	if (_pr->flags.power)
277 		err = push_cxx_to_hypervisor(_pr);
278 
279 	if (_pr->performance && _pr->performance->states)
280 		err |= push_pxx_to_hypervisor(_pr);
281 
282 	mutex_unlock(&acpi_ids_mutex);
283 	return err;
284 }
285 static unsigned int __init get_max_acpi_id(void)
286 {
287 	struct xenpf_pcpuinfo *info;
288 	struct xen_platform_op op = {
289 		.cmd = XENPF_get_cpuinfo,
290 		.interface_version = XENPF_INTERFACE_VERSION,
291 	};
292 	int ret = 0;
293 	unsigned int i, last_cpu, max_acpi_id = 0;
294 
295 	info = &op.u.pcpu_info;
296 	info->xen_cpuid = 0;
297 
298 	ret = HYPERVISOR_platform_op(&op);
299 	if (ret)
300 		return NR_CPUS;
301 
302 	/* The max_present is the same irregardless of the xen_cpuid */
303 	last_cpu = op.u.pcpu_info.max_present;
304 	for (i = 0; i <= last_cpu; i++) {
305 		info->xen_cpuid = i;
306 		ret = HYPERVISOR_platform_op(&op);
307 		if (ret)
308 			continue;
309 		max_acpi_id = max(info->acpi_id, max_acpi_id);
310 	}
311 	max_acpi_id *= 2; /* Slack for CPU hotplug support. */
312 	pr_debug("Max ACPI ID: %u\n", max_acpi_id);
313 	return max_acpi_id;
314 }
315 /*
316  * The read_acpi_id and check_acpi_ids are there to support the Xen
317  * oddity of virtual CPUs != physical CPUs in the initial domain.
318  * The user can supply 'xen_max_vcpus=X' on the Xen hypervisor line
319  * which will band the amount of CPUs the initial domain can see.
320  * In general that is OK, except it plays havoc with any of the
321  * for_each_[present|online]_cpu macros which are banded to the virtual
322  * CPU amount.
323  */
324 static acpi_status
325 read_acpi_id(acpi_handle handle, u32 lvl, void *context, void **rv)
326 {
327 	u32 acpi_id;
328 	acpi_status status;
329 	acpi_object_type acpi_type;
330 	unsigned long long tmp;
331 	union acpi_object object = { 0 };
332 	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
333 	acpi_io_address pblk = 0;
334 
335 	status = acpi_get_type(handle, &acpi_type);
336 	if (ACPI_FAILURE(status))
337 		return AE_OK;
338 
339 	switch (acpi_type) {
340 	case ACPI_TYPE_PROCESSOR:
341 		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
342 		if (ACPI_FAILURE(status))
343 			return AE_OK;
344 		acpi_id = object.processor.proc_id;
345 		pblk = object.processor.pblk_address;
346 		break;
347 	case ACPI_TYPE_DEVICE:
348 		status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
349 		if (ACPI_FAILURE(status))
350 			return AE_OK;
351 		acpi_id = tmp;
352 		break;
353 	default:
354 		return AE_OK;
355 	}
356 	if (invalid_phys_cpuid(acpi_get_phys_id(handle,
357 						acpi_type == ACPI_TYPE_DEVICE,
358 						acpi_id))) {
359 		pr_debug("CPU with ACPI ID %u is unavailable\n", acpi_id);
360 		return AE_OK;
361 	}
362 	/* There are more ACPI Processor objects than in x2APIC or MADT.
363 	 * This can happen with incorrect ACPI SSDT declerations. */
364 	if (acpi_id >= nr_acpi_bits) {
365 		pr_debug("max acpi id %u, trying to set %u\n",
366 			 nr_acpi_bits - 1, acpi_id);
367 		return AE_OK;
368 	}
369 	/* OK, There is a ACPI Processor object */
370 	__set_bit(acpi_id, acpi_id_present);
371 
372 	pr_debug("ACPI CPU%u w/ PBLK:0x%lx\n", acpi_id, (unsigned long)pblk);
373 
374 	/* It has P-state dependencies */
375 	if (!acpi_processor_get_psd(handle, &acpi_psd[acpi_id])) {
376 		pr_debug("ACPI CPU%u w/ PST:coord_type = %llu domain = %llu\n",
377 			 acpi_id, acpi_psd[acpi_id].coord_type,
378 			 acpi_psd[acpi_id].domain);
379 	}
380 
381 	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
382 	if (ACPI_FAILURE(status)) {
383 		if (!pblk)
384 			return AE_OK;
385 	}
386 	/* .. and it has a C-state */
387 	__set_bit(acpi_id, acpi_id_cst_present);
388 
389 	return AE_OK;
390 }
391 static int check_acpi_ids(struct acpi_processor *pr_backup)
392 {
393 
394 	if (!pr_backup)
395 		return -ENODEV;
396 
397 	if (acpi_id_present && acpi_id_cst_present)
398 		/* OK, done this once .. skip to uploading */
399 		goto upload;
400 
401 	/* All online CPUs have been processed at this stage. Now verify
402 	 * whether in fact "online CPUs" == physical CPUs.
403 	 */
404 	acpi_id_present = bitmap_zalloc(nr_acpi_bits, GFP_KERNEL);
405 	if (!acpi_id_present)
406 		return -ENOMEM;
407 
408 	acpi_id_cst_present = bitmap_zalloc(nr_acpi_bits, GFP_KERNEL);
409 	if (!acpi_id_cst_present) {
410 		bitmap_free(acpi_id_present);
411 		return -ENOMEM;
412 	}
413 
414 	acpi_psd = kcalloc(nr_acpi_bits, sizeof(struct acpi_psd_package),
415 			   GFP_KERNEL);
416 	if (!acpi_psd) {
417 		bitmap_free(acpi_id_present);
418 		bitmap_free(acpi_id_cst_present);
419 		return -ENOMEM;
420 	}
421 
422 	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
423 			    ACPI_UINT32_MAX,
424 			    read_acpi_id, NULL, NULL, NULL);
425 	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, read_acpi_id, NULL, NULL);
426 
427 upload:
428 	if (!bitmap_equal(acpi_id_present, acpi_ids_done, nr_acpi_bits)) {
429 		unsigned int i;
430 		for_each_set_bit(i, acpi_id_present, nr_acpi_bits) {
431 			pr_backup->acpi_id = i;
432 			/* Mask out C-states if there are no _CST or PBLK */
433 			pr_backup->flags.power = test_bit(i, acpi_id_cst_present);
434 			/* num_entries is non-zero if we evaluated _PSD */
435 			if (acpi_psd[i].num_entries) {
436 				memcpy(&pr_backup->performance->domain_info,
437 				       &acpi_psd[i],
438 				       sizeof(struct acpi_psd_package));
439 			}
440 			(void)upload_pm_data(pr_backup);
441 		}
442 	}
443 
444 	return 0;
445 }
446 
447 /* acpi_perf_data is a pointer to percpu data. */
448 static struct acpi_processor_performance __percpu *acpi_perf_data;
449 
450 static void free_acpi_perf_data(void)
451 {
452 	unsigned int i;
453 
454 	/* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
455 	for_each_possible_cpu(i)
456 		free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
457 				 ->shared_cpu_map);
458 	free_percpu(acpi_perf_data);
459 }
460 
461 static int xen_upload_processor_pm_data(void)
462 {
463 	struct acpi_processor *pr_backup = NULL;
464 	unsigned int i;
465 	int rc = 0;
466 
467 	pr_info("Uploading Xen processor PM info\n");
468 
469 	for_each_possible_cpu(i) {
470 		struct acpi_processor *_pr;
471 		_pr = per_cpu(processors, i /* APIC ID */);
472 		if (!_pr)
473 			continue;
474 
475 		if (!pr_backup) {
476 			pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
477 			if (pr_backup)
478 				memcpy(pr_backup, _pr, sizeof(struct acpi_processor));
479 		}
480 		(void)upload_pm_data(_pr);
481 	}
482 
483 	rc = check_acpi_ids(pr_backup);
484 	kfree(pr_backup);
485 
486 	return rc;
487 }
488 
489 static void xen_acpi_processor_resume_worker(struct work_struct *dummy)
490 {
491 	int rc;
492 
493 	bitmap_zero(acpi_ids_done, nr_acpi_bits);
494 
495 	rc = xen_upload_processor_pm_data();
496 	if (rc != 0)
497 		pr_info("ACPI data upload failed, error = %d\n", rc);
498 }
499 
500 static void xen_acpi_processor_resume(void)
501 {
502 	static DECLARE_WORK(wq, xen_acpi_processor_resume_worker);
503 
504 	/*
505 	 * xen_upload_processor_pm_data() calls non-atomic code.
506 	 * However, the context for xen_acpi_processor_resume is syscore
507 	 * with only the boot CPU online and in an atomic context.
508 	 *
509 	 * So defer the upload for some point safer.
510 	 */
511 	schedule_work(&wq);
512 }
513 
514 static struct syscore_ops xap_syscore_ops = {
515 	.resume	= xen_acpi_processor_resume,
516 };
517 
518 static int __init xen_acpi_processor_init(void)
519 {
520 	unsigned int i;
521 	int rc;
522 
523 	if (!xen_initial_domain())
524 		return -ENODEV;
525 
526 	nr_acpi_bits = get_max_acpi_id() + 1;
527 	acpi_ids_done = bitmap_zalloc(nr_acpi_bits, GFP_KERNEL);
528 	if (!acpi_ids_done)
529 		return -ENOMEM;
530 
531 	acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
532 	if (!acpi_perf_data) {
533 		pr_debug("Memory allocation error for acpi_perf_data\n");
534 		bitmap_free(acpi_ids_done);
535 		return -ENOMEM;
536 	}
537 	for_each_possible_cpu(i) {
538 		if (!zalloc_cpumask_var_node(
539 			&per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
540 			GFP_KERNEL, cpu_to_node(i))) {
541 			rc = -ENOMEM;
542 			goto err_out;
543 		}
544 	}
545 
546 	/* Do initialization in ACPI core. It is OK to fail here. */
547 	(void)acpi_processor_preregister_performance(acpi_perf_data);
548 
549 	for_each_possible_cpu(i) {
550 		struct acpi_processor *pr;
551 		struct acpi_processor_performance *perf;
552 
553 		pr = per_cpu(processors, i);
554 		perf = per_cpu_ptr(acpi_perf_data, i);
555 		if (!pr)
556 			continue;
557 
558 		pr->performance = perf;
559 		rc = acpi_processor_get_performance_info(pr);
560 		if (rc)
561 			goto err_out;
562 	}
563 
564 	rc = xen_upload_processor_pm_data();
565 	if (rc)
566 		goto err_unregister;
567 
568 	register_syscore_ops(&xap_syscore_ops);
569 
570 	return 0;
571 err_unregister:
572 	for_each_possible_cpu(i)
573 		acpi_processor_unregister_performance(i);
574 
575 err_out:
576 	/* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
577 	free_acpi_perf_data();
578 	bitmap_free(acpi_ids_done);
579 	return rc;
580 }
581 static void __exit xen_acpi_processor_exit(void)
582 {
583 	int i;
584 
585 	unregister_syscore_ops(&xap_syscore_ops);
586 	bitmap_free(acpi_ids_done);
587 	bitmap_free(acpi_id_present);
588 	bitmap_free(acpi_id_cst_present);
589 	kfree(acpi_psd);
590 	for_each_possible_cpu(i)
591 		acpi_processor_unregister_performance(i);
592 
593 	free_acpi_perf_data();
594 }
595 
596 MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
597 MODULE_DESCRIPTION("Xen ACPI Processor P-states (and Cx) driver which uploads PM data to Xen hypervisor");
598 MODULE_LICENSE("GPL");
599 
600 /* We want to be loaded before the CPU freq scaling drivers are loaded.
601  * They are loaded in late_initcall. */
602 device_initcall(xen_acpi_processor_init);
603 module_exit(xen_acpi_processor_exit);
604