cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cpufreq_userspace.c (3724B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2
      3/*
      4 *  linux/drivers/cpufreq/cpufreq_userspace.c
      5 *
      6 *  Copyright (C)  2001 Russell King
      7 *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
      8 */
      9
     10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
     11
     12#include <linux/cpufreq.h>
     13#include <linux/init.h>
     14#include <linux/module.h>
     15#include <linux/mutex.h>
     16#include <linux/slab.h>
     17
     18static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
     19static DEFINE_MUTEX(userspace_mutex);
     20
     21/**
     22 * cpufreq_set - set the CPU frequency
     23 * @policy: pointer to policy struct where freq is being set
     24 * @freq: target frequency in kHz
     25 *
     26 * Sets the CPU frequency to freq.
     27 */
     28static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
     29{
     30	int ret = -EINVAL;
     31	unsigned int *setspeed = policy->governor_data;
     32
     33	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
     34
     35	mutex_lock(&userspace_mutex);
     36	if (!per_cpu(cpu_is_managed, policy->cpu))
     37		goto err;
     38
     39	*setspeed = freq;
     40
     41	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
     42 err:
     43	mutex_unlock(&userspace_mutex);
     44	return ret;
     45}
     46
     47static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
     48{
     49	return sprintf(buf, "%u\n", policy->cur);
     50}
     51
     52static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
     53{
     54	unsigned int *setspeed;
     55
     56	setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);
     57	if (!setspeed)
     58		return -ENOMEM;
     59
     60	policy->governor_data = setspeed;
     61	return 0;
     62}
     63
     64static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
     65{
     66	mutex_lock(&userspace_mutex);
     67	kfree(policy->governor_data);
     68	policy->governor_data = NULL;
     69	mutex_unlock(&userspace_mutex);
     70}
     71
     72static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
     73{
     74	unsigned int *setspeed = policy->governor_data;
     75
     76	BUG_ON(!policy->cur);
     77	pr_debug("started managing cpu %u\n", policy->cpu);
     78
     79	mutex_lock(&userspace_mutex);
     80	per_cpu(cpu_is_managed, policy->cpu) = 1;
     81	*setspeed = policy->cur;
     82	mutex_unlock(&userspace_mutex);
     83	return 0;
     84}
     85
     86static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
     87{
     88	unsigned int *setspeed = policy->governor_data;
     89
     90	pr_debug("managing cpu %u stopped\n", policy->cpu);
     91
     92	mutex_lock(&userspace_mutex);
     93	per_cpu(cpu_is_managed, policy->cpu) = 0;
     94	*setspeed = 0;
     95	mutex_unlock(&userspace_mutex);
     96}
     97
     98static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
     99{
    100	unsigned int *setspeed = policy->governor_data;
    101
    102	mutex_lock(&userspace_mutex);
    103
    104	pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
    105		 policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
    106
    107	if (policy->max < *setspeed)
    108		__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
    109	else if (policy->min > *setspeed)
    110		__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
    111	else
    112		__cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
    113
    114	mutex_unlock(&userspace_mutex);
    115}
    116
    117static struct cpufreq_governor cpufreq_gov_userspace = {
    118	.name		= "userspace",
    119	.init		= cpufreq_userspace_policy_init,
    120	.exit		= cpufreq_userspace_policy_exit,
    121	.start		= cpufreq_userspace_policy_start,
    122	.stop		= cpufreq_userspace_policy_stop,
    123	.limits		= cpufreq_userspace_policy_limits,
    124	.store_setspeed	= cpufreq_set,
    125	.show_setspeed	= show_speed,
    126	.owner		= THIS_MODULE,
    127};
    128
    129MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
    130		"Russell King <rmk@arm.linux.org.uk>");
    131MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
    132MODULE_LICENSE("GPL");
    133
    134#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
    135struct cpufreq_governor *cpufreq_default_governor(void)
    136{
    137	return &cpufreq_gov_userspace;
    138}
    139#endif
    140
    141cpufreq_governor_init(cpufreq_gov_userspace);
    142cpufreq_governor_exit(cpufreq_gov_userspace);