diff options
Diffstat (limited to 'kernel/cpu_pm.c')
| -rw-r--r-- | kernel/cpu_pm.c | 114 |
1 files changed, 57 insertions, 57 deletions
diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c index 67b02e138a47..7481fbb947d3 100644 --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -1,18 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2011 Google, Inc. * * Author: * Colin Cross <ccross@android.com> - * - * This software is licensed under the terms of the GNU General Public - * License version 2, as published by the Free Software Foundation, and - * may be copied, distributed, and modified under those terms. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * */ #include <linux/kernel.h> @@ -22,21 +13,38 @@ #include <linux/spinlock.h> #include <linux/syscore_ops.h> -static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain); +/* + * atomic_notifiers use a spinlock_t, which can block under PREEMPT_RT. + * Notifications for cpu_pm will be issued by the idle task itself, which can + * never block, IOW it requires using a raw_spinlock_t. + */ +static struct { + struct raw_notifier_head chain; + raw_spinlock_t lock; +} cpu_pm_notifier = { + .chain = RAW_NOTIFIER_INIT(cpu_pm_notifier.chain), + .lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock), +}; -static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) +static int cpu_pm_notify(enum cpu_pm_event event) { int ret; - /* - * __atomic_notifier_call_chain has a RCU read critical section, which - * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let - * RCU know this. - */ - rcu_irq_enter_irqson(); - ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, - nr_to_call, nr_calls); - rcu_irq_exit_irqson(); + rcu_read_lock(); + ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL); + rcu_read_unlock(); + + return notifier_to_errno(ret); +} + +static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down) +{ + unsigned long flags; + int ret; + + raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); + ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL); + raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); return notifier_to_errno(ret); } @@ -48,12 +56,17 @@ static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) * Add a driver to a list of drivers that are notified about * CPU and CPU cluster low power entry and exit. * - * This function may sleep, and has the same return conditions as - * raw_notifier_chain_register. + * This function has the same return conditions as raw_notifier_chain_register. */ int cpu_pm_register_notifier(struct notifier_block *nb) { - return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb); + unsigned long flags; + int ret; + + raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); + ret = raw_notifier_chain_register(&cpu_pm_notifier.chain, nb); + raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); + return ret; } EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); @@ -63,12 +76,17 @@ EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); * * Remove a driver from the CPU PM notifier list. * - * This function may sleep, and has the same return conditions as - * raw_notifier_chain_unregister. + * This function has the same return conditions as raw_notifier_chain_unregister. */ int cpu_pm_unregister_notifier(struct notifier_block *nb) { - return atomic_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); + unsigned long flags; + int ret; + + raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags); + ret = raw_notifier_chain_unregister(&cpu_pm_notifier.chain, nb); + raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags); + return ret; } EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); @@ -89,18 +107,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); */ int cpu_pm_enter(void) { - int nr_calls; - int ret = 0; - - ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); - if (ret) - /* - * Inform listeners (nr_calls - 1) about failure of CPU PM - * PM entry who are notified earlier to prepare for it. - */ - cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); - - return ret; + return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED); } EXPORT_SYMBOL_GPL(cpu_pm_enter); @@ -118,7 +125,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter); */ int cpu_pm_exit(void) { - return cpu_pm_notify(CPU_PM_EXIT, -1, NULL); + return cpu_pm_notify(CPU_PM_EXIT); } EXPORT_SYMBOL_GPL(cpu_pm_exit); @@ -140,18 +147,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit); */ int cpu_cluster_pm_enter(void) { - int nr_calls; - int ret = 0; - - ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); - if (ret) - /* - * Inform listeners (nr_calls - 1) about failure of CPU cluster - * PM entry who are notified earlier to prepare for it. - */ - cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); - - return ret; + return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED); } EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); @@ -172,12 +168,12 @@ EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); */ int cpu_cluster_pm_exit(void) { - return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); + return cpu_pm_notify(CPU_CLUSTER_PM_EXIT); } EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); #ifdef CONFIG_PM -static int cpu_pm_suspend(void) +static int cpu_pm_suspend(void *data) { int ret; @@ -189,20 +185,24 @@ static int cpu_pm_suspend(void) return ret; } -static void cpu_pm_resume(void) +static void cpu_pm_resume(void *data) { cpu_cluster_pm_exit(); cpu_pm_exit(); } -static struct syscore_ops cpu_pm_syscore_ops = { +static const struct syscore_ops cpu_pm_syscore_ops = { .suspend = cpu_pm_suspend, .resume = cpu_pm_resume, }; +static struct syscore cpu_pm_syscore = { + .ops = &cpu_pm_syscore_ops, +}; + static int cpu_pm_init(void) { - register_syscore_ops(&cpu_pm_syscore_ops); + register_syscore(&cpu_pm_syscore); return 0; } core_initcall(cpu_pm_init); |