linux/drivers/cpufreq/freq_table.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/cpufreq/freq_table.c
*
* Copyright (C) 2002 - 2003 Dominik Brodowski
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpufreq.h>
#include <linux/module.h>
/*********************************************************************
* FREQUENCY TABLE HELPERS *
*********************************************************************/
bool policy_has_boost_freq(struct cpufreq_policy *policy)
{
struct cpufreq_frequency_table *pos, *table = policy->freq_table;
if (!table)
return false;
cpufreq_for_each_valid_entry(pos, table)
if (pos->flags & CPUFREQ_BOOST_FREQ)
return true;
return false;
}
EXPORT_SYMBOL_GPL(policy_has_boost_freq);
int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
struct cpufreq_frequency_table *table)
{
struct cpufreq_frequency_table *pos;
unsigned int min_freq = ~0;
unsigned int max_freq = 0;
unsigned int freq;
cpufreq_for_each_valid_entry(pos, table) {
freq = pos->frequency;
if (!cpufreq_boost_enabled()
&& (pos->flags & CPUFREQ_BOOST_FREQ))
continue;
pr_debug("table entry %u: %u kHz\n", (int)(pos - table), freq);
if (freq < min_freq)
min_freq = freq;
if (freq > max_freq)
max_freq = freq;
}
policy->min = policy->cpuinfo.min_freq = min_freq;
policy->max = policy->cpuinfo.max_freq = max_freq;
if (policy->min == ~0)
return -EINVAL;
else
return 0;
}
cpufreq: Avoid creating excessively large stack frames In the process of modifying a cpufreq policy, the cpufreq core makes a copy of it including all of the internals which is stored on the CPU stack. Because struct cpufreq_policy is relatively large, this may cause the size of the stack frame to exceed the 2 KB limit and so the GCC complains when -Wframe-larger-than= is used. In fact, it is not necessary to copy the entire policy structure in order to modify it, however. First, because cpufreq_set_policy() obtains the min and max policy limits from frequency QoS now, it is not necessary to pass the limits to it from the callers. The only things that need to be passed to it from there are the new governor pointer or (if there is a built-in governor in the driver) the "policy" value representing the governor choice. They both can be passed as individual arguments, though, so make cpufreq_set_policy() take them this way and rework its callers accordingly. This avoids making copies of cpufreq policies in the callers of cpufreq_set_policy(). Second, cpufreq_set_policy() still needs to pass the new policy data to the ->verify() callback of the cpufreq driver whose task is to sanitize the min and max policy limits. It still does not need to make a full copy of struct cpufreq_policy for this purpose, but it needs to pass a few items from it to the driver in case they are needed (different drivers have different needs in that respect and all of them have to be covered). For this reason, introduce struct cpufreq_policy_data to hold copies of the members of struct cpufreq_policy used by the existing ->verify() driver callbacks and pass a pointer to a temporary structure of that type to ->verify() (instead of passing a pointer to full struct cpufreq_policy to it). While at it, notice that intel_pstate and longrun don't really need to verify the "policy" value in struct cpufreq_policy, so drop those check from them to avoid copying "policy" into struct cpufreq_policy_data (which allows it to be slightly smaller). Also while at it fix up white space in a couple of places and make cpufreq_set_policy() static (as it can be so). Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS") Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-01-26 22:40:11 +00:00
int cpufreq_frequency_table_verify(struct cpufreq_policy_data *policy,
struct cpufreq_frequency_table *table)
{
struct cpufreq_frequency_table *pos;
unsigned int freq, next_larger = ~0;
bool found = false;
pr_debug("request for verification of policy (%u - %u kHz) for cpu %u\n",
policy->min, policy->max, policy->cpu);
cpufreq_verify_within_cpu_limits(policy);
cpufreq_for_each_valid_entry(pos, table) {
freq = pos->frequency;
if ((freq >= policy->min) && (freq <= policy->max)) {
found = true;
break;
}
if ((next_larger > freq) && (freq > policy->max))
next_larger = freq;
}
if (!found) {
policy->max = next_larger;
cpufreq_verify_within_cpu_limits(policy);
}
pr_debug("verification lead to (%u - %u kHz) for cpu %u\n",
policy->min, policy->max, policy->cpu);
return 0;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_verify);
/*
* Generic routine to verify policy & frequency table, requires driver to set
* policy->freq_table prior to it.
*/
cpufreq: Avoid creating excessively large stack frames In the process of modifying a cpufreq policy, the cpufreq core makes a copy of it including all of the internals which is stored on the CPU stack. Because struct cpufreq_policy is relatively large, this may cause the size of the stack frame to exceed the 2 KB limit and so the GCC complains when -Wframe-larger-than= is used. In fact, it is not necessary to copy the entire policy structure in order to modify it, however. First, because cpufreq_set_policy() obtains the min and max policy limits from frequency QoS now, it is not necessary to pass the limits to it from the callers. The only things that need to be passed to it from there are the new governor pointer or (if there is a built-in governor in the driver) the "policy" value representing the governor choice. They both can be passed as individual arguments, though, so make cpufreq_set_policy() take them this way and rework its callers accordingly. This avoids making copies of cpufreq policies in the callers of cpufreq_set_policy(). Second, cpufreq_set_policy() still needs to pass the new policy data to the ->verify() callback of the cpufreq driver whose task is to sanitize the min and max policy limits. It still does not need to make a full copy of struct cpufreq_policy for this purpose, but it needs to pass a few items from it to the driver in case they are needed (different drivers have different needs in that respect and all of them have to be covered). For this reason, introduce struct cpufreq_policy_data to hold copies of the members of struct cpufreq_policy used by the existing ->verify() driver callbacks and pass a pointer to a temporary structure of that type to ->verify() (instead of passing a pointer to full struct cpufreq_policy to it). While at it, notice that intel_pstate and longrun don't really need to verify the "policy" value in struct cpufreq_policy, so drop those check from them to avoid copying "policy" into struct cpufreq_policy_data (which allows it to be slightly smaller). Also while at it fix up white space in a couple of places and make cpufreq_set_policy() static (as it can be so). Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS") Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-01-26 22:40:11 +00:00
int cpufreq_generic_frequency_table_verify(struct cpufreq_policy_data *policy)
{
if (!policy->freq_table)
return -ENODEV;
return cpufreq_frequency_table_verify(policy, policy->freq_table);
}
EXPORT_SYMBOL_GPL(cpufreq_generic_frequency_table_verify);
int cpufreq_table_index_unsorted(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_frequency_table optimal = {
.driver_data = ~0,
.frequency = 0,
};
struct cpufreq_frequency_table suboptimal = {
.driver_data = ~0,
.frequency = 0,
};
struct cpufreq_frequency_table *pos;
struct cpufreq_frequency_table *table = policy->freq_table;
unsigned int freq, diff, i = 0;
int index;
pr_debug("request for target %u kHz (relation: %u) for cpu %u\n",
target_freq, relation, policy->cpu);
switch (relation) {
case CPUFREQ_RELATION_H:
suboptimal.frequency = ~0;
break;
case CPUFREQ_RELATION_L:
case CPUFREQ_RELATION_C:
optimal.frequency = ~0;
break;
}
cpufreq_for_each_valid_entry_idx(pos, table, i) {
freq = pos->frequency;
if ((freq < policy->min) || (freq > policy->max))
continue;
if (freq == target_freq) {
optimal.driver_data = i;
break;
}
switch (relation) {
case CPUFREQ_RELATION_H:
if (freq < target_freq) {
if (freq >= optimal.frequency) {
optimal.frequency = freq;
optimal.driver_data = i;
}
} else {
if (freq <= suboptimal.frequency) {
suboptimal.frequency = freq;
suboptimal.driver_data = i;
}
}
break;
case CPUFREQ_RELATION_L:
if (freq > target_freq) {
if (freq <= optimal.frequency) {
optimal.frequency = freq;
optimal.driver_data = i;
}
} else {
if (freq >= suboptimal.frequency) {
suboptimal.frequency = freq;
suboptimal.driver_data = i;
}
}
break;
case CPUFREQ_RELATION_C:
diff = abs(freq - target_freq);
if (diff < optimal.frequency ||
(diff == optimal.frequency &&
freq > table[optimal.driver_data].frequency)) {
optimal.frequency = diff;
optimal.driver_data = i;
}
break;
}
}
if (optimal.driver_data > i) {
if (suboptimal.driver_data > i) {
WARN(1, "Invalid frequency table: %d\n", policy->cpu);
return 0;
}
index = suboptimal.driver_data;
} else
index = optimal.driver_data;
pr_debug("target index is %u, freq is:%u kHz\n", index,
table[index].frequency);
return index;
}
EXPORT_SYMBOL_GPL(cpufreq_table_index_unsorted);
int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
unsigned int freq)
{
struct cpufreq_frequency_table *pos, *table = policy->freq_table;
int idx;
if (unlikely(!table)) {
pr_debug("%s: Unable to find frequency table\n", __func__);
return -ENOENT;
}
cpufreq_for_each_valid_entry_idx(pos, table, idx)
if (pos->frequency == freq)
return idx;
return -EINVAL;
}
EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index);
/**
* show_available_freqs - show available frequencies for the specified CPU
*/
static ssize_t show_available_freqs(struct cpufreq_policy *policy, char *buf,
bool show_boost)
{
ssize_t count = 0;
struct cpufreq_frequency_table *pos, *table = policy->freq_table;
if (!table)
return -ENODEV;
cpufreq_for_each_valid_entry(pos, table) {
/*
* show_boost = true and driver_data = BOOST freq
* display BOOST freqs
*
* show_boost = false and driver_data = BOOST freq
* show_boost = true and driver_data != BOOST freq
* continue - do not display anything
*
* show_boost = false and driver_data != BOOST freq
* display NON BOOST freqs
*/
if (show_boost ^ (pos->flags & CPUFREQ_BOOST_FREQ))
continue;
count += sprintf(&buf[count], "%d ", pos->frequency);
}
count += sprintf(&buf[count], "\n");
return count;
}
#define cpufreq_attr_available_freq(_name) \
struct freq_attr cpufreq_freq_attr_##_name##_freqs = \
__ATTR_RO(_name##_frequencies)
/**
* show_scaling_available_frequencies - show available normal frequencies for
* the specified CPU
*/
static ssize_t scaling_available_frequencies_show(struct cpufreq_policy *policy,
char *buf)
{
return show_available_freqs(policy, buf, false);
}
cpufreq_attr_available_freq(scaling_available);
EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_available_freqs);
/**
* show_available_boost_freqs - show available boost frequencies for
* the specified CPU
*/
static ssize_t scaling_boost_frequencies_show(struct cpufreq_policy *policy,
char *buf)
{
return show_available_freqs(policy, buf, true);
}
cpufreq_attr_available_freq(scaling_boost);
EXPORT_SYMBOL_GPL(cpufreq_freq_attr_scaling_boost_freqs);
struct freq_attr *cpufreq_generic_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
EXPORT_SYMBOL_GPL(cpufreq_generic_attr);
static int set_freq_table_sorted(struct cpufreq_policy *policy)
{
struct cpufreq_frequency_table *pos, *table = policy->freq_table;
struct cpufreq_frequency_table *prev = NULL;
int ascending = 0;
policy->freq_table_sorted = CPUFREQ_TABLE_UNSORTED;
cpufreq_for_each_valid_entry(pos, table) {
if (!prev) {
prev = pos;
continue;
}
if (pos->frequency == prev->frequency) {
pr_warn("Duplicate freq-table entries: %u\n",
pos->frequency);
return -EINVAL;
}
/* Frequency increased from prev to pos */
if (pos->frequency > prev->frequency) {
/* But frequency was decreasing earlier */
if (ascending < 0) {
pr_debug("Freq table is unsorted\n");
return 0;
}
ascending++;
} else {
/* Frequency decreased from prev to pos */
/* But frequency was increasing earlier */
if (ascending > 0) {
pr_debug("Freq table is unsorted\n");
return 0;
}
ascending--;
}
prev = pos;
}
if (ascending > 0)
policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_ASCENDING;
else
policy->freq_table_sorted = CPUFREQ_TABLE_SORTED_DESCENDING;
pr_debug("Freq table is sorted in %s order\n",
ascending > 0 ? "ascending" : "descending");
return 0;
}
int cpufreq_table_validate_and_sort(struct cpufreq_policy *policy)
{
int ret;
if (!policy->freq_table)
return 0;
ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
if (ret)
return ret;
return set_freq_table_sorted(policy);
}
MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION("CPUfreq frequency table helpers");
MODULE_LICENSE("GPL");