1/*
 2 * Scheduler code and data structures related to cpufreq.
 3 *
 4 * Copyright (C) 2016, Intel Corporation
 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 6 *
 7 * This program is free software; you can redistribute it and/or modify
 8 * it under the terms of the GNU General Public License version 2 as
 9 * published by the Free Software Foundation.
10 */
11
12#include "sched.h"
13
14DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
15
16/**
17 * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
18 * @cpu: The CPU to set the pointer for.
19 * @data: New pointer value.
20 * @func: Callback function to set for the CPU.
21 *
22 * Set and publish the update_util_data pointer for the given CPU.
23 *
24 * The update_util_data pointer of @cpu is set to @data and the callback
25 * function pointer in the target struct update_util_data is set to @func.
26 * That function will be called by cpufreq_update_util() from RCU-sched
27 * read-side critical sections, so it must not sleep.  @data will always be
28 * passed to it as the first argument which allows the function to get to the
29 * target update_util_data structure and its container.
30 *
31 * The update_util_data pointer of @cpu must be NULL when this function is
32 * called or it will WARN() and return with no effect.
33 */
34void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
35			void (*func)(struct update_util_data *data, u64 time,
36				     unsigned int flags))
37{
38	if (WARN_ON(!data || !func))
39		return;
40
41	if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
42		return;
43
44	data->func = func;
45	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
46}
47EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
48
49/**
50 * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
51 * @cpu: The CPU to clear the pointer for.
52 *
53 * Clear the update_util_data pointer for the given CPU.
54 *
55 * Callers must use RCU-sched callbacks to free any memory that might be
56 * accessed via the old update_util_data pointer or invoke synchronize_sched()
57 * right after this function to avoid use-after-free.
58 */
59void cpufreq_remove_update_util_hook(int cpu)
60{
61	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
 
 
 
62}
63EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);

 1/*
 2 * Scheduler code and data structures related to cpufreq.
 3 *
 4 * Copyright (C) 2016, Intel Corporation
 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 6 *
 7 * This program is free software; you can redistribute it and/or modify
 8 * it under the terms of the GNU General Public License version 2 as
 9 * published by the Free Software Foundation.
10 */
11
12#include "sched.h"
13
14DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
15
16/**
17 * cpufreq_set_update_util_data - Populate the CPU's update_util_data pointer.
18 * @cpu: The CPU to set the pointer for.
19 * @data: New pointer value.
 
20 *
21 * Set and publish the update_util_data pointer for the given CPU.  That pointer
22 * points to a struct update_util_data object containing a callback function
23 * to call from cpufreq_update_util().  That function will be called from an RCU
24 * read-side critical section, so it must not sleep.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
25 *
26 * Callers must use RCU-sched callbacks to free any memory that might be
27 * accessed via the old update_util_data pointer or invoke synchronize_sched()
28 * right after this function to avoid use-after-free.
29 */
30void cpufreq_set_update_util_data(int cpu, struct update_util_data *data)
31{
32	if (WARN_ON(data && !data->func))
33		return;
34
35	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
36}
37EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data);