1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * Scheduler code and data structures related 3 * Scheduler code and data structures related to cpufreq.
4 * 4 *
5 * Copyright (C) 2016, Intel Corporation 5 * Copyright (C) 2016, Intel Corporation
6 * Author: Rafael J. Wysocki <rafael.j.wysocki 6 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7 */ 7 */
>> 8 #include <linux/cpufreq.h>
>> 9
>> 10 #include "sched.h"
8 11
9 DEFINE_PER_CPU(struct update_util_data __rcu * 12 DEFINE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
10 13
11 /** 14 /**
12 * cpufreq_add_update_util_hook - Populate the 15 * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
13 * @cpu: The CPU to set the pointer for. 16 * @cpu: The CPU to set the pointer for.
14 * @data: New pointer value. 17 * @data: New pointer value.
15 * @func: Callback function to set for the CPU 18 * @func: Callback function to set for the CPU.
16 * 19 *
17 * Set and publish the update_util_data pointe 20 * Set and publish the update_util_data pointer for the given CPU.
18 * 21 *
19 * The update_util_data pointer of @cpu is set 22 * The update_util_data pointer of @cpu is set to @data and the callback
20 * function pointer in the target struct updat 23 * function pointer in the target struct update_util_data is set to @func.
21 * That function will be called by cpufreq_upd 24 * That function will be called by cpufreq_update_util() from RCU-sched
22 * read-side critical sections, so it must not 25 * read-side critical sections, so it must not sleep. @data will always be
23 * passed to it as the first argument which al 26 * passed to it as the first argument which allows the function to get to the
24 * target update_util_data structure and its c 27 * target update_util_data structure and its container.
25 * 28 *
26 * The update_util_data pointer of @cpu must b 29 * The update_util_data pointer of @cpu must be NULL when this function is
27 * called or it will WARN() and return with no 30 * called or it will WARN() and return with no effect.
28 */ 31 */
29 void cpufreq_add_update_util_hook(int cpu, str 32 void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
30 void (*func)(struct up 33 void (*func)(struct update_util_data *data, u64 time,
31 unsigned 34 unsigned int flags))
32 { 35 {
33 if (WARN_ON(!data || !func)) 36 if (WARN_ON(!data || !func))
34 return; 37 return;
35 38
36 if (WARN_ON(per_cpu(cpufreq_update_uti 39 if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
37 return; 40 return;
38 41
39 data->func = func; 42 data->func = func;
40 rcu_assign_pointer(per_cpu(cpufreq_upd 43 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
41 } 44 }
42 EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook 45 EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
43 46
44 /** 47 /**
45 * cpufreq_remove_update_util_hook - Clear the 48 * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
46 * @cpu: The CPU to clear the pointer for. 49 * @cpu: The CPU to clear the pointer for.
47 * 50 *
48 * Clear the update_util_data pointer for the 51 * Clear the update_util_data pointer for the given CPU.
49 * 52 *
50 * Callers must use RCU callbacks to free any 53 * Callers must use RCU callbacks to free any memory that might be
51 * accessed via the old update_util_data point 54 * accessed via the old update_util_data pointer or invoke synchronize_rcu()
52 * right after this function to avoid use-afte 55 * right after this function to avoid use-after-free.
53 */ 56 */
54 void cpufreq_remove_update_util_hook(int cpu) 57 void cpufreq_remove_update_util_hook(int cpu)
55 { 58 {
56 rcu_assign_pointer(per_cpu(cpufreq_upd 59 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
57 } 60 }
58 EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_h 61 EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);
59 62
60 /** 63 /**
61 * cpufreq_this_cpu_can_update - Check if cpuf 64 * cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated.
62 * @policy: cpufreq policy to check. 65 * @policy: cpufreq policy to check.
63 * 66 *
64 * Return 'true' if: 67 * Return 'true' if:
65 * - the local and remote CPUs share @policy, 68 * - the local and remote CPUs share @policy,
66 * - dvfs_possible_from_any_cpu is set in @pol 69 * - dvfs_possible_from_any_cpu is set in @policy and the local CPU is not going
67 * offline (in which case it is not expected 70 * offline (in which case it is not expected to run cpufreq updates any more).
68 */ 71 */
69 bool cpufreq_this_cpu_can_update(struct cpufre 72 bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy)
70 { 73 {
71 return cpumask_test_cpu(smp_processor_ 74 return cpumask_test_cpu(smp_processor_id(), policy->cpus) ||
72 (policy->dvfs_possible_from_an 75 (policy->dvfs_possible_from_any_cpu &&
73 rcu_dereference_sched(*this_c 76 rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)));
74 } 77 }
75 78
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