ACPI: sanity check _PSS frequency to prevent cpufreq crash
[linux-2.6.git] / drivers / acpi / processor_perflib.c
1 /*
2  * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8  *                      - Added processor hotplug support
9  *
10  *
11  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12  *
13  *  This program is free software; you can redistribute it and/or modify
14  *  it under the terms of the GNU General Public License as published by
15  *  the Free Software Foundation; either version 2 of the License, or (at
16  *  your option) any later version.
17  *
18  *  This program is distributed in the hope that it will be useful, but
19  *  WITHOUT ANY WARRANTY; without even the implied warranty of
20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  *  General Public License for more details.
22  *
23  *  You should have received a copy of the GNU General Public License along
24  *  with this program; if not, write to the Free Software Foundation, Inc.,
25  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26  *
27  */
28
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/cpufreq.h>
33
34 #ifdef CONFIG_X86
35 #include <asm/cpufeature.h>
36 #endif
37
38 #include <acpi/acpi_bus.h>
39 #include <acpi/acpi_drivers.h>
40 #include <acpi/processor.h>
41
42 #define ACPI_PROCESSOR_CLASS            "processor"
43 #define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
44 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
45 ACPI_MODULE_NAME("processor_perflib");
46
47 static DEFINE_MUTEX(performance_mutex);
48
49 /* Use cpufreq debug layer for _PPC changes. */
50 #define cpufreq_printk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
51                                                 "cpufreq-core", msg)
52
53 /*
54  * _PPC support is implemented as a CPUfreq policy notifier:
55  * This means each time a CPUfreq driver registered also with
56  * the ACPI core is asked to change the speed policy, the maximum
57  * value is adjusted so that it is within the platform limit.
58  *
59  * Also, when a new platform limit value is detected, the CPUfreq
60  * policy is adjusted accordingly.
61  */
62
63 /* ignore_ppc:
64  * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
65  *       ignore _PPC
66  *  0 -> cpufreq low level drivers initialized -> consider _PPC values
67  *  1 -> ignore _PPC totally -> forced by user through boot param
68  */
69 static int ignore_ppc = -1;
70 module_param(ignore_ppc, int, 0644);
71 MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
72                  "limited by BIOS, this should help");
73
74 #define PPC_REGISTERED   1
75 #define PPC_IN_USE       2
76
77 static int acpi_processor_ppc_status;
78
79 static int acpi_processor_ppc_notifier(struct notifier_block *nb,
80                                        unsigned long event, void *data)
81 {
82         struct cpufreq_policy *policy = data;
83         struct acpi_processor *pr;
84         unsigned int ppc = 0;
85
86         if (event == CPUFREQ_START && ignore_ppc <= 0) {
87                 ignore_ppc = 0;
88                 return 0;
89         }
90
91         if (ignore_ppc)
92                 return 0;
93
94         if (event != CPUFREQ_INCOMPATIBLE)
95                 return 0;
96
97         mutex_lock(&performance_mutex);
98
99         pr = per_cpu(processors, policy->cpu);
100         if (!pr || !pr->performance)
101                 goto out;
102
103         ppc = (unsigned int)pr->performance_platform_limit;
104
105         if (ppc >= pr->performance->state_count)
106                 goto out;
107
108         cpufreq_verify_within_limits(policy, 0,
109                                      pr->performance->states[ppc].
110                                      core_frequency * 1000);
111
112       out:
113         mutex_unlock(&performance_mutex);
114
115         return 0;
116 }
117
118 static struct notifier_block acpi_ppc_notifier_block = {
119         .notifier_call = acpi_processor_ppc_notifier,
120 };
121
122 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
123 {
124         acpi_status status = 0;
125         unsigned long long ppc = 0;
126
127
128         if (!pr)
129                 return -EINVAL;
130
131         /*
132          * _PPC indicates the maximum state currently supported by the platform
133          * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
134          */
135         status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
136
137         if (status != AE_NOT_FOUND)
138                 acpi_processor_ppc_status |= PPC_IN_USE;
139
140         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
141                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
142                 return -ENODEV;
143         }
144
145         cpufreq_printk("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
146                        (int)ppc, ppc ? "" : "not");
147
148         pr->performance_platform_limit = (int)ppc;
149
150         return 0;
151 }
152
153 int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
154 {
155         int ret;
156
157         if (ignore_ppc)
158                 return 0;
159
160         ret = acpi_processor_get_platform_limit(pr);
161
162         if (ret < 0)
163                 return (ret);
164         else
165                 return cpufreq_update_policy(pr->id);
166 }
167
168 void acpi_processor_ppc_init(void)
169 {
170         if (!cpufreq_register_notifier
171             (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
172                 acpi_processor_ppc_status |= PPC_REGISTERED;
173         else
174                 printk(KERN_DEBUG
175                        "Warning: Processor Platform Limit not supported.\n");
176 }
177
178 void acpi_processor_ppc_exit(void)
179 {
180         if (acpi_processor_ppc_status & PPC_REGISTERED)
181                 cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
182                                             CPUFREQ_POLICY_NOTIFIER);
183
184         acpi_processor_ppc_status &= ~PPC_REGISTERED;
185 }
186
187 static int acpi_processor_get_performance_control(struct acpi_processor *pr)
188 {
189         int result = 0;
190         acpi_status status = 0;
191         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
192         union acpi_object *pct = NULL;
193         union acpi_object obj = { 0 };
194
195
196         status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
197         if (ACPI_FAILURE(status)) {
198                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
199                 return -ENODEV;
200         }
201
202         pct = (union acpi_object *)buffer.pointer;
203         if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
204             || (pct->package.count != 2)) {
205                 printk(KERN_ERR PREFIX "Invalid _PCT data\n");
206                 result = -EFAULT;
207                 goto end;
208         }
209
210         /*
211          * control_register
212          */
213
214         obj = pct->package.elements[0];
215
216         if ((obj.type != ACPI_TYPE_BUFFER)
217             || (obj.buffer.length < sizeof(struct acpi_pct_register))
218             || (obj.buffer.pointer == NULL)) {
219                 printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
220                 result = -EFAULT;
221                 goto end;
222         }
223         memcpy(&pr->performance->control_register, obj.buffer.pointer,
224                sizeof(struct acpi_pct_register));
225
226         /*
227          * status_register
228          */
229
230         obj = pct->package.elements[1];
231
232         if ((obj.type != ACPI_TYPE_BUFFER)
233             || (obj.buffer.length < sizeof(struct acpi_pct_register))
234             || (obj.buffer.pointer == NULL)) {
235                 printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
236                 result = -EFAULT;
237                 goto end;
238         }
239
240         memcpy(&pr->performance->status_register, obj.buffer.pointer,
241                sizeof(struct acpi_pct_register));
242
243       end:
244         kfree(buffer.pointer);
245
246         return result;
247 }
248
249 static int acpi_processor_get_performance_states(struct acpi_processor *pr)
250 {
251         int result = 0;
252         acpi_status status = AE_OK;
253         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
254         struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
255         struct acpi_buffer state = { 0, NULL };
256         union acpi_object *pss = NULL;
257         int i;
258
259
260         status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
261         if (ACPI_FAILURE(status)) {
262                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
263                 return -ENODEV;
264         }
265
266         pss = buffer.pointer;
267         if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
268                 printk(KERN_ERR PREFIX "Invalid _PSS data\n");
269                 result = -EFAULT;
270                 goto end;
271         }
272
273         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
274                           pss->package.count));
275
276         pr->performance->state_count = pss->package.count;
277         pr->performance->states =
278             kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
279                     GFP_KERNEL);
280         if (!pr->performance->states) {
281                 result = -ENOMEM;
282                 goto end;
283         }
284
285         for (i = 0; i < pr->performance->state_count; i++) {
286
287                 struct acpi_processor_px *px = &(pr->performance->states[i]);
288
289                 state.length = sizeof(struct acpi_processor_px);
290                 state.pointer = px;
291
292                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
293
294                 status = acpi_extract_package(&(pss->package.elements[i]),
295                                               &format, &state);
296                 if (ACPI_FAILURE(status)) {
297                         ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
298                         result = -EFAULT;
299                         kfree(pr->performance->states);
300                         goto end;
301                 }
302
303                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
304                                   "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
305                                   i,
306                                   (u32) px->core_frequency,
307                                   (u32) px->power,
308                                   (u32) px->transition_latency,
309                                   (u32) px->bus_master_latency,
310                                   (u32) px->control, (u32) px->status));
311
312                 /*
313                  * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
314                  */
315                 if (!px->core_frequency ||
316                     ((u32)(px->core_frequency * 1000) !=
317                      (px->core_frequency * 1000))) {
318                         printk(KERN_ERR FW_BUG PREFIX
319                                "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
320                                px->core_frequency);
321                         result = -EFAULT;
322                         kfree(pr->performance->states);
323                         goto end;
324                 }
325         }
326
327       end:
328         kfree(buffer.pointer);
329
330         return result;
331 }
332
333 static int acpi_processor_get_performance_info(struct acpi_processor *pr)
334 {
335         int result = 0;
336         acpi_status status = AE_OK;
337         acpi_handle handle = NULL;
338
339         if (!pr || !pr->performance || !pr->handle)
340                 return -EINVAL;
341
342         status = acpi_get_handle(pr->handle, "_PCT", &handle);
343         if (ACPI_FAILURE(status)) {
344                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
345                                   "ACPI-based processor performance control unavailable\n"));
346                 return -ENODEV;
347         }
348
349         result = acpi_processor_get_performance_control(pr);
350         if (result)
351                 goto update_bios;
352
353         result = acpi_processor_get_performance_states(pr);
354         if (result)
355                 goto update_bios;
356
357         return 0;
358
359         /*
360          * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
361          * the BIOS is older than the CPU and does not know its frequencies
362          */
363  update_bios:
364 #ifdef CONFIG_X86
365         if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
366                 if(boot_cpu_has(X86_FEATURE_EST))
367                         printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
368                                "frequency support\n");
369         }
370 #endif
371         return result;
372 }
373
374 int acpi_processor_notify_smm(struct module *calling_module)
375 {
376         acpi_status status;
377         static int is_done = 0;
378
379
380         if (!(acpi_processor_ppc_status & PPC_REGISTERED))
381                 return -EBUSY;
382
383         if (!try_module_get(calling_module))
384                 return -EINVAL;
385
386         /* is_done is set to negative if an error occured,
387          * and to postitive if _no_ error occured, but SMM
388          * was already notified. This avoids double notification
389          * which might lead to unexpected results...
390          */
391         if (is_done > 0) {
392                 module_put(calling_module);
393                 return 0;
394         } else if (is_done < 0) {
395                 module_put(calling_module);
396                 return is_done;
397         }
398
399         is_done = -EIO;
400
401         /* Can't write pstate_control to smi_command if either value is zero */
402         if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
403                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
404                 module_put(calling_module);
405                 return 0;
406         }
407
408         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
409                           "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
410                           acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
411
412         status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
413                                     (u32) acpi_gbl_FADT.pstate_control, 8);
414         if (ACPI_FAILURE(status)) {
415                 ACPI_EXCEPTION((AE_INFO, status,
416                                 "Failed to write pstate_control [0x%x] to "
417                                 "smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
418                                 acpi_gbl_FADT.smi_command));
419                 module_put(calling_module);
420                 return status;
421         }
422
423         /* Success. If there's no _PPC, we need to fear nothing, so
424          * we can allow the cpufreq driver to be rmmod'ed. */
425         is_done = 1;
426
427         if (!(acpi_processor_ppc_status & PPC_IN_USE))
428                 module_put(calling_module);
429
430         return 0;
431 }
432
433 EXPORT_SYMBOL(acpi_processor_notify_smm);
434
435 static int acpi_processor_get_psd(struct acpi_processor *pr)
436 {
437         int result = 0;
438         acpi_status status = AE_OK;
439         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
440         struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
441         struct acpi_buffer state = {0, NULL};
442         union acpi_object  *psd = NULL;
443         struct acpi_psd_package *pdomain;
444
445         status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
446         if (ACPI_FAILURE(status)) {
447                 return -ENODEV;
448         }
449
450         psd = buffer.pointer;
451         if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
452                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
453                 result = -EFAULT;
454                 goto end;
455         }
456
457         if (psd->package.count != 1) {
458                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
459                 result = -EFAULT;
460                 goto end;
461         }
462
463         pdomain = &(pr->performance->domain_info);
464
465         state.length = sizeof(struct acpi_psd_package);
466         state.pointer = pdomain;
467
468         status = acpi_extract_package(&(psd->package.elements[0]),
469                 &format, &state);
470         if (ACPI_FAILURE(status)) {
471                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
472                 result = -EFAULT;
473                 goto end;
474         }
475
476         if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
477                 printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
478                 result = -EFAULT;
479                 goto end;
480         }
481
482         if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
483                 printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
484                 result = -EFAULT;
485                 goto end;
486         }
487
488         if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
489             pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
490             pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
491                 printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
492                 result = -EFAULT;
493                 goto end;
494         }
495 end:
496         kfree(buffer.pointer);
497         return result;
498 }
499
500 int acpi_processor_preregister_performance(
501                 struct acpi_processor_performance *performance)
502 {
503         int count, count_target;
504         int retval = 0;
505         unsigned int i, j;
506         cpumask_var_t covered_cpus;
507         struct acpi_processor *pr;
508         struct acpi_psd_package *pdomain;
509         struct acpi_processor *match_pr;
510         struct acpi_psd_package *match_pdomain;
511
512         if (!alloc_cpumask_var(&covered_cpus, GFP_KERNEL))
513                 return -ENOMEM;
514
515         mutex_lock(&performance_mutex);
516
517         /*
518          * Check if another driver has already registered, and abort before
519          * changing pr->performance if it has. Check input data as well.
520          */
521         for_each_possible_cpu(i) {
522                 pr = per_cpu(processors, i);
523                 if (!pr) {
524                         /* Look only at processors in ACPI namespace */
525                         continue;
526                 }
527
528                 if (pr->performance) {
529                         retval = -EBUSY;
530                         goto err_out;
531                 }
532
533                 if (!performance || !per_cpu_ptr(performance, i)) {
534                         retval = -EINVAL;
535                         goto err_out;
536                 }
537         }
538
539         /* Call _PSD for all CPUs */
540         for_each_possible_cpu(i) {
541                 pr = per_cpu(processors, i);
542                 if (!pr)
543                         continue;
544
545                 pr->performance = per_cpu_ptr(performance, i);
546                 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
547                 if (acpi_processor_get_psd(pr)) {
548                         retval = -EINVAL;
549                         continue;
550                 }
551         }
552         if (retval)
553                 goto err_ret;
554
555         /*
556          * Now that we have _PSD data from all CPUs, lets setup P-state 
557          * domain info.
558          */
559         cpumask_clear(covered_cpus);
560         for_each_possible_cpu(i) {
561                 pr = per_cpu(processors, i);
562                 if (!pr)
563                         continue;
564
565                 if (cpumask_test_cpu(i, covered_cpus))
566                         continue;
567
568                 pdomain = &(pr->performance->domain_info);
569                 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
570                 cpumask_set_cpu(i, covered_cpus);
571                 if (pdomain->num_processors <= 1)
572                         continue;
573
574                 /* Validate the Domain info */
575                 count_target = pdomain->num_processors;
576                 count = 1;
577                 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
578                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
579                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
580                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
581                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
582                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
583
584                 for_each_possible_cpu(j) {
585                         if (i == j)
586                                 continue;
587
588                         match_pr = per_cpu(processors, j);
589                         if (!match_pr)
590                                 continue;
591
592                         match_pdomain = &(match_pr->performance->domain_info);
593                         if (match_pdomain->domain != pdomain->domain)
594                                 continue;
595
596                         /* Here i and j are in the same domain */
597
598                         if (match_pdomain->num_processors != count_target) {
599                                 retval = -EINVAL;
600                                 goto err_ret;
601                         }
602
603                         if (pdomain->coord_type != match_pdomain->coord_type) {
604                                 retval = -EINVAL;
605                                 goto err_ret;
606                         }
607
608                         cpumask_set_cpu(j, covered_cpus);
609                         cpumask_set_cpu(j, pr->performance->shared_cpu_map);
610                         count++;
611                 }
612
613                 for_each_possible_cpu(j) {
614                         if (i == j)
615                                 continue;
616
617                         match_pr = per_cpu(processors, j);
618                         if (!match_pr)
619                                 continue;
620
621                         match_pdomain = &(match_pr->performance->domain_info);
622                         if (match_pdomain->domain != pdomain->domain)
623                                 continue;
624
625                         match_pr->performance->shared_type = 
626                                         pr->performance->shared_type;
627                         cpumask_copy(match_pr->performance->shared_cpu_map,
628                                      pr->performance->shared_cpu_map);
629                 }
630         }
631
632 err_ret:
633         for_each_possible_cpu(i) {
634                 pr = per_cpu(processors, i);
635                 if (!pr || !pr->performance)
636                         continue;
637
638                 /* Assume no coordination on any error parsing domain info */
639                 if (retval) {
640                         cpumask_clear(pr->performance->shared_cpu_map);
641                         cpumask_set_cpu(i, pr->performance->shared_cpu_map);
642                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
643                 }
644                 pr->performance = NULL; /* Will be set for real in register */
645         }
646
647 err_out:
648         mutex_unlock(&performance_mutex);
649         free_cpumask_var(covered_cpus);
650         return retval;
651 }
652 EXPORT_SYMBOL(acpi_processor_preregister_performance);
653
654 int
655 acpi_processor_register_performance(struct acpi_processor_performance
656                                     *performance, unsigned int cpu)
657 {
658         struct acpi_processor *pr;
659
660         if (!(acpi_processor_ppc_status & PPC_REGISTERED))
661                 return -EINVAL;
662
663         mutex_lock(&performance_mutex);
664
665         pr = per_cpu(processors, cpu);
666         if (!pr) {
667                 mutex_unlock(&performance_mutex);
668                 return -ENODEV;
669         }
670
671         if (pr->performance) {
672                 mutex_unlock(&performance_mutex);
673                 return -EBUSY;
674         }
675
676         WARN_ON(!performance);
677
678         pr->performance = performance;
679
680         if (acpi_processor_get_performance_info(pr)) {
681                 pr->performance = NULL;
682                 mutex_unlock(&performance_mutex);
683                 return -EIO;
684         }
685
686         mutex_unlock(&performance_mutex);
687         return 0;
688 }
689
690 EXPORT_SYMBOL(acpi_processor_register_performance);
691
692 void
693 acpi_processor_unregister_performance(struct acpi_processor_performance
694                                       *performance, unsigned int cpu)
695 {
696         struct acpi_processor *pr;
697
698         mutex_lock(&performance_mutex);
699
700         pr = per_cpu(processors, cpu);
701         if (!pr) {
702                 mutex_unlock(&performance_mutex);
703                 return;
704         }
705
706         if (pr->performance)
707                 kfree(pr->performance->states);
708         pr->performance = NULL;
709
710         mutex_unlock(&performance_mutex);
711
712         return;
713 }
714
715 EXPORT_SYMBOL(acpi_processor_unregister_performance);