alistair23-linux/drivers/acpi/processor_perflib.c
Rafael J. Wysocki 5a25e3f7cc cpufreq: intel_pstate: Driver-specific handling of _PPC updates
In some cases, the platform firmware disables or enables turbo
frequencies for all CPUs globally before triggering a _PPC change
notification for one of them.  Obviously, that global change affects
all CPUs, not just the notified one, and it needs to be acted upon by
cpufreq.

The intel_pstate driver is able to detect such global changes of
the settings, but it also needs to update policy limits for all
CPUs if that happens, in particular if turbo frequencies are
enabled globally - to allow them to be used.

For this reason, introduce a new cpufreq driver callback to be
invoked on _PPC notifications, if present, instead of simply
calling cpufreq_update_policy() for the notified CPU and make
intel_pstate use it to trigger policy updates for all CPUs
in the system if global settings change.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-01 23:43:05 +02:00

812 lines
20 KiB
C

/*
* processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
*
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#ifdef CONFIG_X86
#include <asm/cpufeature.h>
#endif
#define PREFIX "ACPI: "
#define ACPI_PROCESSOR_CLASS "processor"
#define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_perflib");
static DEFINE_MUTEX(performance_mutex);
/*
* _PPC support is implemented as a CPUfreq policy notifier:
* This means each time a CPUfreq driver registered also with
* the ACPI core is asked to change the speed policy, the maximum
* value is adjusted so that it is within the platform limit.
*
* Also, when a new platform limit value is detected, the CPUfreq
* policy is adjusted accordingly.
*/
/* ignore_ppc:
* -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
* ignore _PPC
* 0 -> cpufreq low level drivers initialized -> consider _PPC values
* 1 -> ignore _PPC totally -> forced by user through boot param
*/
static int ignore_ppc = -1;
module_param(ignore_ppc, int, 0644);
MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
"limited by BIOS, this should help");
#define PPC_REGISTERED 1
#define PPC_IN_USE 2
static int acpi_processor_ppc_status;
static int acpi_processor_ppc_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
struct acpi_processor *pr;
unsigned int ppc = 0;
if (ignore_ppc < 0)
ignore_ppc = 0;
if (ignore_ppc)
return 0;
if (event != CPUFREQ_ADJUST)
return 0;
mutex_lock(&performance_mutex);
pr = per_cpu(processors, policy->cpu);
if (!pr || !pr->performance)
goto out;
ppc = (unsigned int)pr->performance_platform_limit;
if (ppc >= pr->performance->state_count)
goto out;
cpufreq_verify_within_limits(policy, 0,
pr->performance->states[ppc].
core_frequency * 1000);
out:
mutex_unlock(&performance_mutex);
return 0;
}
static struct notifier_block acpi_ppc_notifier_block = {
.notifier_call = acpi_processor_ppc_notifier,
};
static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
acpi_status status = 0;
unsigned long long ppc = 0;
if (!pr)
return -EINVAL;
/*
* _PPC indicates the maximum state currently supported by the platform
* (e.g. 0 = states 0..n; 1 = states 1..n; etc.
*/
status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
if (status != AE_NOT_FOUND)
acpi_processor_ppc_status |= PPC_IN_USE;
if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
return -ENODEV;
}
pr_debug("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
(int)ppc, ppc ? "" : "not");
pr->performance_platform_limit = (int)ppc;
return 0;
}
#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
/*
* acpi_processor_ppc_ost: Notify firmware the _PPC evaluation status
* @handle: ACPI processor handle
* @status: the status code of _PPC evaluation
* 0: success. OSPM is now using the performance state specificed.
* 1: failure. OSPM has not changed the number of P-states in use
*/
static void acpi_processor_ppc_ost(acpi_handle handle, int status)
{
if (acpi_has_method(handle, "_OST"))
acpi_evaluate_ost(handle, ACPI_PROCESSOR_NOTIFY_PERFORMANCE,
status, NULL);
}
void acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)
{
int ret;
if (ignore_ppc || !pr->performance) {
/*
* Only when it is notification event, the _OST object
* will be evaluated. Otherwise it is skipped.
*/
if (event_flag)
acpi_processor_ppc_ost(pr->handle, 1);
return;
}
ret = acpi_processor_get_platform_limit(pr);
/*
* Only when it is notification event, the _OST object
* will be evaluated. Otherwise it is skipped.
*/
if (event_flag) {
if (ret < 0)
acpi_processor_ppc_ost(pr->handle, 1);
else
acpi_processor_ppc_ost(pr->handle, 0);
}
if (ret >= 0)
cpufreq_update_limits(pr->id);
}
int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
{
struct acpi_processor *pr;
pr = per_cpu(processors, cpu);
if (!pr || !pr->performance || !pr->performance->state_count)
return -ENODEV;
*limit = pr->performance->states[pr->performance_platform_limit].
core_frequency * 1000;
return 0;
}
EXPORT_SYMBOL(acpi_processor_get_bios_limit);
void acpi_processor_ppc_init(void)
{
if (!cpufreq_register_notifier
(&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
acpi_processor_ppc_status |= PPC_REGISTERED;
else
printk(KERN_DEBUG
"Warning: Processor Platform Limit not supported.\n");
}
void acpi_processor_ppc_exit(void)
{
if (acpi_processor_ppc_status & PPC_REGISTERED)
cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
acpi_processor_ppc_status &= ~PPC_REGISTERED;
}
static int acpi_processor_get_performance_control(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = 0;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *pct = NULL;
union acpi_object obj = { 0 };
status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
return -ENODEV;
}
pct = (union acpi_object *)buffer.pointer;
if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
|| (pct->package.count != 2)) {
printk(KERN_ERR PREFIX "Invalid _PCT data\n");
result = -EFAULT;
goto end;
}
/*
* control_register
*/
obj = pct->package.elements[0];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_pct_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->performance->control_register, obj.buffer.pointer,
sizeof(struct acpi_pct_register));
/*
* status_register
*/
obj = pct->package.elements[1];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_pct_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->performance->status_register, obj.buffer.pointer,
sizeof(struct acpi_pct_register));
end:
kfree(buffer.pointer);
return result;
}
#ifdef CONFIG_X86
/*
* Some AMDs have 50MHz frequency multiples, but only provide 100MHz rounding
* in their ACPI data. Calculate the real values and fix up the _PSS data.
*/
static void amd_fixup_frequency(struct acpi_processor_px *px, int i)
{
u32 hi, lo, fid, did;
int index = px->control & 0x00000007;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
return;
if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
|| boot_cpu_data.x86 == 0x11) {
rdmsr(MSR_AMD_PSTATE_DEF_BASE + index, lo, hi);
/*
* MSR C001_0064+:
* Bit 63: PstateEn. Read-write. If set, the P-state is valid.
*/
if (!(hi & BIT(31)))
return;
fid = lo & 0x3f;
did = (lo >> 6) & 7;
if (boot_cpu_data.x86 == 0x10)
px->core_frequency = (100 * (fid + 0x10)) >> did;
else
px->core_frequency = (100 * (fid + 8)) >> did;
}
}
#else
static void amd_fixup_frequency(struct acpi_processor_px *px, int i) {};
#endif
static int acpi_processor_get_performance_states(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
struct acpi_buffer state = { 0, NULL };
union acpi_object *pss = NULL;
int i;
int last_invalid = -1;
status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
return -ENODEV;
}
pss = buffer.pointer;
if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
printk(KERN_ERR PREFIX "Invalid _PSS data\n");
result = -EFAULT;
goto end;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
pss->package.count));
pr->performance->state_count = pss->package.count;
pr->performance->states =
kmalloc_array(pss->package.count,
sizeof(struct acpi_processor_px),
GFP_KERNEL);
if (!pr->performance->states) {
result = -ENOMEM;
goto end;
}
for (i = 0; i < pr->performance->state_count; i++) {
struct acpi_processor_px *px = &(pr->performance->states[i]);
state.length = sizeof(struct acpi_processor_px);
state.pointer = px;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
status = acpi_extract_package(&(pss->package.elements[i]),
&format, &state);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
result = -EFAULT;
kfree(pr->performance->states);
goto end;
}
amd_fixup_frequency(px, i);
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
i,
(u32) px->core_frequency,
(u32) px->power,
(u32) px->transition_latency,
(u32) px->bus_master_latency,
(u32) px->control, (u32) px->status));
/*
* Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
*/
if (!px->core_frequency ||
((u32)(px->core_frequency * 1000) !=
(px->core_frequency * 1000))) {
printk(KERN_ERR FW_BUG PREFIX
"Invalid BIOS _PSS frequency found for processor %d: 0x%llx MHz\n",
pr->id, px->core_frequency);
if (last_invalid == -1)
last_invalid = i;
} else {
if (last_invalid != -1) {
/*
* Copy this valid entry over last_invalid entry
*/
memcpy(&(pr->performance->states[last_invalid]),
px, sizeof(struct acpi_processor_px));
++last_invalid;
}
}
}
if (last_invalid == 0) {
printk(KERN_ERR FW_BUG PREFIX
"No valid BIOS _PSS frequency found for processor %d\n", pr->id);
result = -EFAULT;
kfree(pr->performance->states);
pr->performance->states = NULL;
}
if (last_invalid > 0)
pr->performance->state_count = last_invalid;
end:
kfree(buffer.pointer);
return result;
}
int acpi_processor_get_performance_info(struct acpi_processor *pr)
{
int result = 0;
if (!pr || !pr->performance || !pr->handle)
return -EINVAL;
if (!acpi_has_method(pr->handle, "_PCT")) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"ACPI-based processor performance control unavailable\n"));
return -ENODEV;
}
result = acpi_processor_get_performance_control(pr);
if (result)
goto update_bios;
result = acpi_processor_get_performance_states(pr);
if (result)
goto update_bios;
/* We need to call _PPC once when cpufreq starts */
if (ignore_ppc != 1)
result = acpi_processor_get_platform_limit(pr);
return result;
/*
* Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
* the BIOS is older than the CPU and does not know its frequencies
*/
update_bios:
#ifdef CONFIG_X86
if (acpi_has_method(pr->handle, "_PPC")) {
if(boot_cpu_has(X86_FEATURE_EST))
printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
"frequency support\n");
}
#endif
return result;
}
EXPORT_SYMBOL_GPL(acpi_processor_get_performance_info);
int acpi_processor_pstate_control(void)
{
acpi_status status;
if (!acpi_gbl_FADT.smi_command || !acpi_gbl_FADT.pstate_control)
return 0;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Writing pstate_control [0x%x] to smi_command [0x%x]\n",
acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
(u32)acpi_gbl_FADT.pstate_control, 8);
if (ACPI_SUCCESS(status))
return 1;
ACPI_EXCEPTION((AE_INFO, status,
"Failed to write pstate_control [0x%x] to smi_command [0x%x]",
acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
return -EIO;
}
int acpi_processor_notify_smm(struct module *calling_module)
{
static int is_done = 0;
int result;
if (!(acpi_processor_ppc_status & PPC_REGISTERED))
return -EBUSY;
if (!try_module_get(calling_module))
return -EINVAL;
/* is_done is set to negative if an error occurred,
* and to postitive if _no_ error occurred, but SMM
* was already notified. This avoids double notification
* which might lead to unexpected results...
*/
if (is_done > 0) {
module_put(calling_module);
return 0;
} else if (is_done < 0) {
module_put(calling_module);
return is_done;
}
is_done = -EIO;
result = acpi_processor_pstate_control();
if (!result) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
module_put(calling_module);
return 0;
}
if (result < 0) {
module_put(calling_module);
return result;
}
/* Success. If there's no _PPC, we need to fear nothing, so
* we can allow the cpufreq driver to be rmmod'ed. */
is_done = 1;
if (!(acpi_processor_ppc_status & PPC_IN_USE))
module_put(calling_module);
return 0;
}
EXPORT_SYMBOL(acpi_processor_notify_smm);
int acpi_processor_get_psd(acpi_handle handle, struct acpi_psd_package *pdomain)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
struct acpi_buffer state = {0, NULL};
union acpi_object *psd = NULL;
status = acpi_evaluate_object(handle, "_PSD", NULL, &buffer);
if (ACPI_FAILURE(status)) {
return -ENODEV;
}
psd = buffer.pointer;
if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
printk(KERN_ERR PREFIX "Invalid _PSD data\n");
result = -EFAULT;
goto end;
}
if (psd->package.count != 1) {
printk(KERN_ERR PREFIX "Invalid _PSD data\n");
result = -EFAULT;
goto end;
}
state.length = sizeof(struct acpi_psd_package);
state.pointer = pdomain;
status = acpi_extract_package(&(psd->package.elements[0]),
&format, &state);
if (ACPI_FAILURE(status)) {
printk(KERN_ERR PREFIX "Invalid _PSD data\n");
result = -EFAULT;
goto end;
}
if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
result = -EFAULT;
goto end;
}
if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
result = -EFAULT;
goto end;
}
if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
result = -EFAULT;
goto end;
}
end:
kfree(buffer.pointer);
return result;
}
EXPORT_SYMBOL(acpi_processor_get_psd);
int acpi_processor_preregister_performance(
struct acpi_processor_performance __percpu *performance)
{
int count_target;
int retval = 0;
unsigned int i, j;
cpumask_var_t covered_cpus;
struct acpi_processor *pr;
struct acpi_psd_package *pdomain;
struct acpi_processor *match_pr;
struct acpi_psd_package *match_pdomain;
if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
return -ENOMEM;
mutex_lock(&performance_mutex);
/*
* Check if another driver has already registered, and abort before
* changing pr->performance if it has. Check input data as well.
*/
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr) {
/* Look only at processors in ACPI namespace */
continue;
}
if (pr->performance) {
retval = -EBUSY;
goto err_out;
}
if (!performance || !per_cpu_ptr(performance, i)) {
retval = -EINVAL;
goto err_out;
}
}
/* Call _PSD for all CPUs */
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr)
continue;
pr->performance = per_cpu_ptr(performance, i);
cpumask_set_cpu(i, pr->performance->shared_cpu_map);
pdomain = &(pr->performance->domain_info);
if (acpi_processor_get_psd(pr->handle, pdomain)) {
retval = -EINVAL;
continue;
}
}
if (retval)
goto err_ret;
/*
* Now that we have _PSD data from all CPUs, lets setup P-state
* domain info.
*/
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr)
continue;
if (cpumask_test_cpu(i, covered_cpus))
continue;
pdomain = &(pr->performance->domain_info);
cpumask_set_cpu(i, pr->performance->shared_cpu_map);
cpumask_set_cpu(i, covered_cpus);
if (pdomain->num_processors <= 1)
continue;
/* Validate the Domain info */
count_target = pdomain->num_processors;
if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
for_each_possible_cpu(j) {
if (i == j)
continue;
match_pr = per_cpu(processors, j);
if (!match_pr)
continue;
match_pdomain = &(match_pr->performance->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
/* Here i and j are in the same domain */
if (match_pdomain->num_processors != count_target) {
retval = -EINVAL;
goto err_ret;
}
if (pdomain->coord_type != match_pdomain->coord_type) {
retval = -EINVAL;
goto err_ret;
}
cpumask_set_cpu(j, covered_cpus);
cpumask_set_cpu(j, pr->performance->shared_cpu_map);
}
for_each_possible_cpu(j) {
if (i == j)
continue;
match_pr = per_cpu(processors, j);
if (!match_pr)
continue;
match_pdomain = &(match_pr->performance->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
match_pr->performance->shared_type =
pr->performance->shared_type;
cpumask_copy(match_pr->performance->shared_cpu_map,
pr->performance->shared_cpu_map);
}
}
err_ret:
for_each_possible_cpu(i) {
pr = per_cpu(processors, i);
if (!pr || !pr->performance)
continue;
/* Assume no coordination on any error parsing domain info */
if (retval) {
cpumask_clear(pr->performance->shared_cpu_map);
cpumask_set_cpu(i, pr->performance->shared_cpu_map);
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
}
pr->performance = NULL; /* Will be set for real in register */
}
err_out:
mutex_unlock(&performance_mutex);
free_cpumask_var(covered_cpus);
return retval;
}
EXPORT_SYMBOL(acpi_processor_preregister_performance);
int
acpi_processor_register_performance(struct acpi_processor_performance
*performance, unsigned int cpu)
{
struct acpi_processor *pr;
if (!(acpi_processor_ppc_status & PPC_REGISTERED))
return -EINVAL;
mutex_lock(&performance_mutex);
pr = per_cpu(processors, cpu);
if (!pr) {
mutex_unlock(&performance_mutex);
return -ENODEV;
}
if (pr->performance) {
mutex_unlock(&performance_mutex);
return -EBUSY;
}
WARN_ON(!performance);
pr->performance = performance;
if (acpi_processor_get_performance_info(pr)) {
pr->performance = NULL;
mutex_unlock(&performance_mutex);
return -EIO;
}
mutex_unlock(&performance_mutex);
return 0;
}
EXPORT_SYMBOL(acpi_processor_register_performance);
void acpi_processor_unregister_performance(unsigned int cpu)
{
struct acpi_processor *pr;
mutex_lock(&performance_mutex);
pr = per_cpu(processors, cpu);
if (!pr) {
mutex_unlock(&performance_mutex);
return;
}
if (pr->performance)
kfree(pr->performance->states);
pr->performance = NULL;
mutex_unlock(&performance_mutex);
return;
}
EXPORT_SYMBOL(acpi_processor_unregister_performance);