ACPI: Move definition of PREFIX from acpi_bus.h to internal..h
[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 PREFIX "ACPI: "
43
44 #define ACPI_PROCESSOR_CLASS            "processor"
45 #define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
46 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
47 ACPI_MODULE_NAME("processor_perflib");
48
49 static DEFINE_MUTEX(performance_mutex);
50
51 /* Use cpufreq debug layer for _PPC changes. */
52 #define cpufreq_printk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
53                                                 "cpufreq-core", msg)
54
55 /*
56  * _PPC support is implemented as a CPUfreq policy notifier:
57  * This means each time a CPUfreq driver registered also with
58  * the ACPI core is asked to change the speed policy, the maximum
59  * value is adjusted so that it is within the platform limit.
60  *
61  * Also, when a new platform limit value is detected, the CPUfreq
62  * policy is adjusted accordingly.
63  */
64
65 /* ignore_ppc:
66  * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
67  *       ignore _PPC
68  *  0 -> cpufreq low level drivers initialized -> consider _PPC values
69  *  1 -> ignore _PPC totally -> forced by user through boot param
70  */
71 static int ignore_ppc = -1;
72 module_param(ignore_ppc, int, 0644);
73 MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
74                  "limited by BIOS, this should help");
75
76 #define PPC_REGISTERED   1
77 #define PPC_IN_USE       2
78
79 static int acpi_processor_ppc_status;
80
81 static int acpi_processor_ppc_notifier(struct notifier_block *nb,
82                                        unsigned long event, void *data)
83 {
84         struct cpufreq_policy *policy = data;
85         struct acpi_processor *pr;
86         unsigned int ppc = 0;
87
88         if (event == CPUFREQ_START && ignore_ppc <= 0) {
89                 ignore_ppc = 0;
90                 return 0;
91         }
92
93         if (ignore_ppc)
94                 return 0;
95
96         if (event != CPUFREQ_INCOMPATIBLE)
97                 return 0;
98
99         mutex_lock(&performance_mutex);
100
101         pr = per_cpu(processors, policy->cpu);
102         if (!pr || !pr->performance)
103                 goto out;
104
105         ppc = (unsigned int)pr->performance_platform_limit;
106
107         if (ppc >= pr->performance->state_count)
108                 goto out;
109
110         cpufreq_verify_within_limits(policy, 0,
111                                      pr->performance->states[ppc].
112                                      core_frequency * 1000);
113
114       out:
115         mutex_unlock(&performance_mutex);
116
117         return 0;
118 }
119
120 static struct notifier_block acpi_ppc_notifier_block = {
121         .notifier_call = acpi_processor_ppc_notifier,
122 };
123
124 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
125 {
126         acpi_status status = 0;
127         unsigned long long ppc = 0;
128
129
130         if (!pr)
131                 return -EINVAL;
132
133         /*
134          * _PPC indicates the maximum state currently supported by the platform
135          * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
136          */
137         status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
138
139         if (status != AE_NOT_FOUND)
140                 acpi_processor_ppc_status |= PPC_IN_USE;
141
142         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
143                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
144                 return -ENODEV;
145         }
146
147         cpufreq_printk("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
148                        (int)ppc, ppc ? "" : "not");
149
150         pr->performance_platform_limit = (int)ppc;
151
152         return 0;
153 }
154
155 int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
156 {
157         int ret;
158
159         if (ignore_ppc)
160                 return 0;
161
162         ret = acpi_processor_get_platform_limit(pr);
163
164         if (ret < 0)
165                 return (ret);
166         else
167                 return cpufreq_update_policy(pr->id);
168 }
169
170 void acpi_processor_ppc_init(void)
171 {
172         if (!cpufreq_register_notifier
173             (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
174                 acpi_processor_ppc_status |= PPC_REGISTERED;
175         else
176                 printk(KERN_DEBUG
177                        "Warning: Processor Platform Limit not supported.\n");
178 }
179
180 void acpi_processor_ppc_exit(void)
181 {
182         if (acpi_processor_ppc_status & PPC_REGISTERED)
183                 cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
184                                             CPUFREQ_POLICY_NOTIFIER);
185
186         acpi_processor_ppc_status &= ~PPC_REGISTERED;
187 }
188
189 static int acpi_processor_get_performance_control(struct acpi_processor *pr)
190 {
191         int result = 0;
192         acpi_status status = 0;
193         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
194         union acpi_object *pct = NULL;
195         union acpi_object obj = { 0 };
196
197
198         status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
199         if (ACPI_FAILURE(status)) {
200                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
201                 return -ENODEV;
202         }
203
204         pct = (union acpi_object *)buffer.pointer;
205         if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
206             || (pct->package.count != 2)) {
207                 printk(KERN_ERR PREFIX "Invalid _PCT data\n");
208                 result = -EFAULT;
209                 goto end;
210         }
211
212         /*
213          * control_register
214          */
215
216         obj = pct->package.elements[0];
217
218         if ((obj.type != ACPI_TYPE_BUFFER)
219             || (obj.buffer.length < sizeof(struct acpi_pct_register))
220             || (obj.buffer.pointer == NULL)) {
221                 printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
222                 result = -EFAULT;
223                 goto end;
224         }
225         memcpy(&pr->performance->control_register, obj.buffer.pointer,
226                sizeof(struct acpi_pct_register));
227
228         /*
229          * status_register
230          */
231
232         obj = pct->package.elements[1];
233
234         if ((obj.type != ACPI_TYPE_BUFFER)
235             || (obj.buffer.length < sizeof(struct acpi_pct_register))
236             || (obj.buffer.pointer == NULL)) {
237                 printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
238                 result = -EFAULT;
239                 goto end;
240         }
241
242         memcpy(&pr->performance->status_register, obj.buffer.pointer,
243                sizeof(struct acpi_pct_register));
244
245       end:
246         kfree(buffer.pointer);
247
248         return result;
249 }
250
251 static int acpi_processor_get_performance_states(struct acpi_processor *pr)
252 {
253         int result = 0;
254         acpi_status status = AE_OK;
255         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
256         struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
257         struct acpi_buffer state = { 0, NULL };
258         union acpi_object *pss = NULL;
259         int i;
260
261
262         status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
263         if (ACPI_FAILURE(status)) {
264                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
265                 return -ENODEV;
266         }
267
268         pss = buffer.pointer;
269         if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
270                 printk(KERN_ERR PREFIX "Invalid _PSS data\n");
271                 result = -EFAULT;
272                 goto end;
273         }
274
275         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
276                           pss->package.count));
277
278         pr->performance->state_count = pss->package.count;
279         pr->performance->states =
280             kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
281                     GFP_KERNEL);
282         if (!pr->performance->states) {
283                 result = -ENOMEM;
284                 goto end;
285         }
286
287         for (i = 0; i < pr->performance->state_count; i++) {
288
289                 struct acpi_processor_px *px = &(pr->performance->states[i]);
290
291                 state.length = sizeof(struct acpi_processor_px);
292                 state.pointer = px;
293
294                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
295
296                 status = acpi_extract_package(&(pss->package.elements[i]),
297                                               &format, &state);
298                 if (ACPI_FAILURE(status)) {
299                         ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
300                         result = -EFAULT;
301                         kfree(pr->performance->states);
302                         goto end;
303                 }
304
305                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
306                                   "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
307                                   i,
308                                   (u32) px->core_frequency,
309                                   (u32) px->power,
310                                   (u32) px->transition_latency,
311                                   (u32) px->bus_master_latency,
312                                   (u32) px->control, (u32) px->status));
313
314                 /*
315                  * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
316                  */
317                 if (!px->core_frequency ||
318                     ((u32)(px->core_frequency * 1000) !=
319                      (px->core_frequency * 1000))) {
320                         printk(KERN_ERR FW_BUG PREFIX
321                                "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
322                                px->core_frequency);
323                         result = -EFAULT;
324                         kfree(pr->performance->states);
325                         goto end;
326                 }
327         }
328
329       end:
330         kfree(buffer.pointer);
331
332         return result;
333 }
334
335 static int acpi_processor_get_performance_info(struct acpi_processor *pr)
336 {
337         int result = 0;
338         acpi_status status = AE_OK;
339         acpi_handle handle = NULL;
340
341         if (!pr || !pr->performance || !pr->handle)
342                 return -EINVAL;
343
344         status = acpi_get_handle(pr->handle, "_PCT", &handle);
345         if (ACPI_FAILURE(status)) {
346                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
347                                   "ACPI-based processor performance control unavailable\n"));
348                 return -ENODEV;
349         }
350
351         result = acpi_processor_get_performance_control(pr);
352         if (result)
353                 goto update_bios;
354
355         result = acpi_processor_get_performance_states(pr);
356         if (result)
357                 goto update_bios;
358
359         return 0;
360
361         /*
362          * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
363          * the BIOS is older than the CPU and does not know its frequencies
364          */
365  update_bios:
366 #ifdef CONFIG_X86
367         if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
368                 if(boot_cpu_has(X86_FEATURE_EST))
369                         printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
370                                "frequency support\n");
371         }
372 #endif
373         return result;
374 }
375
376 int acpi_processor_notify_smm(struct module *calling_module)
377 {
378         acpi_status status;
379         static int is_done = 0;
380
381
382         if (!(acpi_processor_ppc_status & PPC_REGISTERED))
383                 return -EBUSY;
384
385         if (!try_module_get(calling_module))
386                 return -EINVAL;
387
388         /* is_done is set to negative if an error occured,
389          * and to postitive if _no_ error occured, but SMM
390          * was already notified. This avoids double notification
391          * which might lead to unexpected results...
392          */
393         if (is_done > 0) {
394                 module_put(calling_module);
395                 return 0;
396         } else if (is_done < 0) {
397                 module_put(calling_module);
398                 return is_done;
399         }
400
401         is_done = -EIO;
402
403         /* Can't write pstate_control to smi_command if either value is zero */
404         if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
405                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
406                 module_put(calling_module);
407                 return 0;
408         }
409
410         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
411                           "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
412                           acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
413
414         status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
415                                     (u32) acpi_gbl_FADT.pstate_control, 8);
416         if (ACPI_FAILURE(status)) {
417                 ACPI_EXCEPTION((AE_INFO, status,
418                                 "Failed to write pstate_control [0x%x] to "
419                                 "smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
420                                 acpi_gbl_FADT.smi_command));
421                 module_put(calling_module);
422                 return status;
423         }
424
425         /* Success. If there's no _PPC, we need to fear nothing, so
426          * we can allow the cpufreq driver to be rmmod'ed. */
427         is_done = 1;
428
429         if (!(acpi_processor_ppc_status & PPC_IN_USE))
430                 module_put(calling_module);
431
432         return 0;
433 }
434
435 EXPORT_SYMBOL(acpi_processor_notify_smm);
436
437 static int acpi_processor_get_psd(struct acpi_processor *pr)
438 {
439         int result = 0;
440         acpi_status status = AE_OK;
441         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
442         struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
443         struct acpi_buffer state = {0, NULL};
444         union acpi_object  *psd = NULL;
445         struct acpi_psd_package *pdomain;
446
447         status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
448         if (ACPI_FAILURE(status)) {
449                 return -ENODEV;
450         }
451
452         psd = buffer.pointer;
453         if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
454                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
455                 result = -EFAULT;
456                 goto end;
457         }
458
459         if (psd->package.count != 1) {
460                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
461                 result = -EFAULT;
462                 goto end;
463         }
464
465         pdomain = &(pr->performance->domain_info);
466
467         state.length = sizeof(struct acpi_psd_package);
468         state.pointer = pdomain;
469
470         status = acpi_extract_package(&(psd->package.elements[0]),
471                 &format, &state);
472         if (ACPI_FAILURE(status)) {
473                 printk(KERN_ERR PREFIX "Invalid _PSD data\n");
474                 result = -EFAULT;
475                 goto end;
476         }
477
478         if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
479                 printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
480                 result = -EFAULT;
481                 goto end;
482         }
483
484         if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
485                 printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
486                 result = -EFAULT;
487                 goto end;
488         }
489
490         if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
491             pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
492             pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
493                 printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
494                 result = -EFAULT;
495                 goto end;
496         }
497 end:
498         kfree(buffer.pointer);
499         return result;
500 }
501
502 int acpi_processor_preregister_performance(
503                 struct acpi_processor_performance *performance)
504 {
505         int count, count_target;
506         int retval = 0;
507         unsigned int i, j;
508         cpumask_var_t covered_cpus;
509         struct acpi_processor *pr;
510         struct acpi_psd_package *pdomain;
511         struct acpi_processor *match_pr;
512         struct acpi_psd_package *match_pdomain;
513
514         if (!alloc_cpumask_var(&covered_cpus, GFP_KERNEL))
515                 return -ENOMEM;
516
517         mutex_lock(&performance_mutex);
518
519         /*
520          * Check if another driver has already registered, and abort before
521          * changing pr->performance if it has. Check input data as well.
522          */
523         for_each_possible_cpu(i) {
524                 pr = per_cpu(processors, i);
525                 if (!pr) {
526                         /* Look only at processors in ACPI namespace */
527                         continue;
528                 }
529
530                 if (pr->performance) {
531                         retval = -EBUSY;
532                         goto err_out;
533                 }
534
535                 if (!performance || !per_cpu_ptr(performance, i)) {
536                         retval = -EINVAL;
537                         goto err_out;
538                 }
539         }
540
541         /* Call _PSD for all CPUs */
542         for_each_possible_cpu(i) {
543                 pr = per_cpu(processors, i);
544                 if (!pr)
545                         continue;
546
547                 pr->performance = per_cpu_ptr(performance, i);
548                 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
549                 if (acpi_processor_get_psd(pr)) {
550                         retval = -EINVAL;
551                         continue;
552                 }
553         }
554         if (retval)
555                 goto err_ret;
556
557         /*
558          * Now that we have _PSD data from all CPUs, lets setup P-state 
559          * domain info.
560          */
561         cpumask_clear(covered_cpus);
562         for_each_possible_cpu(i) {
563                 pr = per_cpu(processors, i);
564                 if (!pr)
565                         continue;
566
567                 if (cpumask_test_cpu(i, covered_cpus))
568                         continue;
569
570                 pdomain = &(pr->performance->domain_info);
571                 cpumask_set_cpu(i, pr->performance->shared_cpu_map);
572                 cpumask_set_cpu(i, covered_cpus);
573                 if (pdomain->num_processors <= 1)
574                         continue;
575
576                 /* Validate the Domain info */
577                 count_target = pdomain->num_processors;
578                 count = 1;
579                 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
580                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
581                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
582                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
583                 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
584                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
585
586                 for_each_possible_cpu(j) {
587                         if (i == j)
588                                 continue;
589
590                         match_pr = per_cpu(processors, j);
591                         if (!match_pr)
592                                 continue;
593
594                         match_pdomain = &(match_pr->performance->domain_info);
595                         if (match_pdomain->domain != pdomain->domain)
596                                 continue;
597
598                         /* Here i and j are in the same domain */
599
600                         if (match_pdomain->num_processors != count_target) {
601                                 retval = -EINVAL;
602                                 goto err_ret;
603                         }
604
605                         if (pdomain->coord_type != match_pdomain->coord_type) {
606                                 retval = -EINVAL;
607                                 goto err_ret;
608                         }
609
610                         cpumask_set_cpu(j, covered_cpus);
611                         cpumask_set_cpu(j, pr->performance->shared_cpu_map);
612                         count++;
613                 }
614
615                 for_each_possible_cpu(j) {
616                         if (i == j)
617                                 continue;
618
619                         match_pr = per_cpu(processors, j);
620                         if (!match_pr)
621                                 continue;
622
623                         match_pdomain = &(match_pr->performance->domain_info);
624                         if (match_pdomain->domain != pdomain->domain)
625                                 continue;
626
627                         match_pr->performance->shared_type = 
628                                         pr->performance->shared_type;
629                         cpumask_copy(match_pr->performance->shared_cpu_map,
630                                      pr->performance->shared_cpu_map);
631                 }
632         }
633
634 err_ret:
635         for_each_possible_cpu(i) {
636                 pr = per_cpu(processors, i);
637                 if (!pr || !pr->performance)
638                         continue;
639
640                 /* Assume no coordination on any error parsing domain info */
641                 if (retval) {
642                         cpumask_clear(pr->performance->shared_cpu_map);
643                         cpumask_set_cpu(i, pr->performance->shared_cpu_map);
644                         pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
645                 }
646                 pr->performance = NULL; /* Will be set for real in register */
647         }
648
649 err_out:
650         mutex_unlock(&performance_mutex);
651         free_cpumask_var(covered_cpus);
652         return retval;
653 }
654 EXPORT_SYMBOL(acpi_processor_preregister_performance);
655
656 int
657 acpi_processor_register_performance(struct acpi_processor_performance
658                                     *performance, unsigned int cpu)
659 {
660         struct acpi_processor *pr;
661
662         if (!(acpi_processor_ppc_status & PPC_REGISTERED))
663                 return -EINVAL;
664
665         mutex_lock(&performance_mutex);
666
667         pr = per_cpu(processors, cpu);
668         if (!pr) {
669                 mutex_unlock(&performance_mutex);
670                 return -ENODEV;
671         }
672
673         if (pr->performance) {
674                 mutex_unlock(&performance_mutex);
675                 return -EBUSY;
676         }
677
678         WARN_ON(!performance);
679
680         pr->performance = performance;
681
682         if (acpi_processor_get_performance_info(pr)) {
683                 pr->performance = NULL;
684                 mutex_unlock(&performance_mutex);
685                 return -EIO;
686         }
687
688         mutex_unlock(&performance_mutex);
689         return 0;
690 }
691
692 EXPORT_SYMBOL(acpi_processor_register_performance);
693
694 void
695 acpi_processor_unregister_performance(struct acpi_processor_performance
696                                       *performance, unsigned int cpu)
697 {
698         struct acpi_processor *pr;
699
700         mutex_lock(&performance_mutex);
701
702         pr = per_cpu(processors, cpu);
703         if (!pr) {
704                 mutex_unlock(&performance_mutex);
705                 return;
706         }
707
708         if (pr->performance)
709                 kfree(pr->performance->states);
710         pr->performance = NULL;
711
712         mutex_unlock(&performance_mutex);
713
714         return;
715 }
716
717 EXPORT_SYMBOL(acpi_processor_unregister_performance);