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108c35a9 | 1 | // SPDX-License-Identifier: GPL-2.0 |
adaf9fcd RW |
2 | /* |
3 | * Scheduler code and data structures related to cpufreq. | |
4 | * | |
5 | * Copyright (C) 2016, Intel Corporation | |
6 | * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> | |
adaf9fcd | 7 | */ |
adaf9fcd RW |
8 | #include "sched.h" |
9 | ||
b10abd0a | 10 | DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data); |
adaf9fcd RW |
11 | |
12 | /** | |
0bed612b | 13 | * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. |
adaf9fcd RW |
14 | * @cpu: The CPU to set the pointer for. |
15 | * @data: New pointer value. | |
0bed612b | 16 | * @func: Callback function to set for the CPU. |
adaf9fcd | 17 | * |
0bed612b | 18 | * Set and publish the update_util_data pointer for the given CPU. |
adaf9fcd | 19 | * |
0bed612b RW |
20 | * The update_util_data pointer of @cpu is set to @data and the callback |
21 | * function pointer in the target struct update_util_data is set to @func. | |
22 | * That function will be called by cpufreq_update_util() from RCU-sched | |
23 | * read-side critical sections, so it must not sleep. @data will always be | |
24 | * passed to it as the first argument which allows the function to get to the | |
25 | * target update_util_data structure and its container. | |
26 | * | |
27 | * The update_util_data pointer of @cpu must be NULL when this function is | |
28 | * called or it will WARN() and return with no effect. | |
adaf9fcd | 29 | */ |
0bed612b RW |
30 | void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, |
31 | void (*func)(struct update_util_data *data, u64 time, | |
58919e83 | 32 | unsigned int flags)) |
adaf9fcd | 33 | { |
0bed612b | 34 | if (WARN_ON(!data || !func)) |
adaf9fcd RW |
35 | return; |
36 | ||
0bed612b RW |
37 | if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) |
38 | return; | |
39 | ||
40 | data->func = func; | |
adaf9fcd RW |
41 | rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); |
42 | } | |
0bed612b RW |
43 | EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); |
44 | ||
45 | /** | |
46 | * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. | |
47 | * @cpu: The CPU to clear the pointer for. | |
48 | * | |
49 | * Clear the update_util_data pointer for the given CPU. | |
50 | * | |
b290ebcf PM |
51 | * Callers must use RCU callbacks to free any memory that might be |
52 | * accessed via the old update_util_data pointer or invoke synchronize_rcu() | |
0bed612b RW |
53 | * right after this function to avoid use-after-free. |
54 | */ | |
55 | void cpufreq_remove_update_util_hook(int cpu) | |
56 | { | |
57 | rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL); | |
58 | } | |
59 | EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook); |