| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Scheduler code and data structures related to cpufreq. |
| * |
| * Copyright (C) 2016, Intel Corporation |
| * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| */ |
| #include "sched.h" |
| |
| DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); |
| |
| /** |
| * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. |
| * @cpu: The CPU to set the pointer for. |
| * @data: New pointer value. |
| * @func: Callback function to set for the CPU. |
| * |
| * Set and publish the update_util_data pointer for the given CPU. |
| * |
| * The update_util_data pointer of @cpu is set to @data and the callback |
| * function pointer in the target struct update_util_data is set to @func. |
| * That function will be called by cpufreq_update_util() from RCU-sched |
| * read-side critical sections, so it must not sleep. @data will always be |
| * passed to it as the first argument which allows the function to get to the |
| * target update_util_data structure and its container. |
| * |
| * The update_util_data pointer of @cpu must be NULL when this function is |
| * called or it will WARN() and return with no effect. |
| */ |
| void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, |
| void (*func)(struct update_util_data *data, u64 time, |
| unsigned int flags)) |
| { |
| if (WARN_ON(!data || !func)) |
| return; |
| |
| if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) |
| return; |
| |
| data->func = func; |
| rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); |
| } |
| EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); |
| |
| /** |
| * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. |
| * @cpu: The CPU to clear the pointer for. |
| * |
| * Clear the update_util_data pointer for the given CPU. |
| * |
| * Callers must use RCU callbacks to free any memory that might be |
| * accessed via the old update_util_data pointer or invoke synchronize_rcu() |
| * right after this function to avoid use-after-free. |
| */ |
| void cpufreq_remove_update_util_hook(int cpu) |
| { |
| rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL); |
| } |
| EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook); |