mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
b5945214b7
cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.
Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.
Let's fix this.
Fixes: ab10023e00
("cpu_pm: Add cpu power management notifiers")
Cc: stable@vger.kernel.org
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
201 lines
5.6 KiB
C
201 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2011 Google, Inc.
|
|
*
|
|
* Author:
|
|
* Colin Cross <ccross@android.com>
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/cpu_pm.h>
|
|
#include <linux/module.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/syscore_ops.h>
|
|
|
|
static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain);
|
|
|
|
static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls)
|
|
{
|
|
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();
|
|
|
|
return notifier_to_errno(ret);
|
|
}
|
|
|
|
/**
|
|
* cpu_pm_register_notifier - register a driver with cpu_pm
|
|
* @nb: notifier block to register
|
|
*
|
|
* 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.
|
|
*/
|
|
int cpu_pm_register_notifier(struct notifier_block *nb)
|
|
{
|
|
return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
|
|
|
|
/**
|
|
* cpu_pm_unregister_notifier - unregister a driver with cpu_pm
|
|
* @nb: notifier block to be unregistered
|
|
*
|
|
* Remove a driver from the CPU PM notifier list.
|
|
*
|
|
* This function may sleep, and 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);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
|
|
|
|
/**
|
|
* cpu_pm_enter - CPU low power entry notifier
|
|
*
|
|
* Notifies listeners that a single CPU is entering a low power state that may
|
|
* cause some blocks in the same power domain as the cpu to reset.
|
|
*
|
|
* Must be called on the affected CPU with interrupts disabled. Platform is
|
|
* responsible for ensuring that cpu_pm_enter is not called twice on the same
|
|
* CPU before cpu_pm_exit is called. Notified drivers can include VFP
|
|
* co-processor, interrupt controller and its PM extensions, local CPU
|
|
* timers context save/restore which shouldn't be interrupted. Hence it
|
|
* must be called with interrupts disabled.
|
|
*
|
|
* Return conditions are same as __raw_notifier_call_chain.
|
|
*/
|
|
int cpu_pm_enter(void)
|
|
{
|
|
int nr_calls = 0;
|
|
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;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_pm_enter);
|
|
|
|
/**
|
|
* cpu_pm_exit - CPU low power exit notifier
|
|
*
|
|
* Notifies listeners that a single CPU is exiting a low power state that may
|
|
* have caused some blocks in the same power domain as the cpu to reset.
|
|
*
|
|
* Notified drivers can include VFP co-processor, interrupt controller
|
|
* and its PM extensions, local CPU timers context save/restore which
|
|
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
|
|
*
|
|
* Return conditions are same as __raw_notifier_call_chain.
|
|
*/
|
|
int cpu_pm_exit(void)
|
|
{
|
|
return cpu_pm_notify(CPU_PM_EXIT, -1, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_pm_exit);
|
|
|
|
/**
|
|
* cpu_cluster_pm_enter - CPU cluster low power entry notifier
|
|
*
|
|
* Notifies listeners that all cpus in a power domain are entering a low power
|
|
* state that may cause some blocks in the same power domain to reset.
|
|
*
|
|
* Must be called after cpu_pm_enter has been called on all cpus in the power
|
|
* domain, and before cpu_pm_exit has been called on any cpu in the power
|
|
* domain. Notified drivers can include VFP co-processor, interrupt controller
|
|
* and its PM extensions, local CPU timers context save/restore which
|
|
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
|
|
*
|
|
* Must be called with interrupts disabled.
|
|
*
|
|
* Return conditions are same as __raw_notifier_call_chain.
|
|
*/
|
|
int cpu_cluster_pm_enter(void)
|
|
{
|
|
int nr_calls = 0;
|
|
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;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
|
|
|
|
/**
|
|
* cpu_cluster_pm_exit - CPU cluster low power exit notifier
|
|
*
|
|
* Notifies listeners that all cpus in a power domain are exiting form a
|
|
* low power state that may have caused some blocks in the same power domain
|
|
* to reset.
|
|
*
|
|
* Must be called after cpu_cluster_pm_enter has been called for the power
|
|
* domain, and before cpu_pm_exit has been called on any cpu in the power
|
|
* domain. Notified drivers can include VFP co-processor, interrupt controller
|
|
* and its PM extensions, local CPU timers context save/restore which
|
|
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
|
|
*
|
|
* Return conditions are same as __raw_notifier_call_chain.
|
|
*/
|
|
int cpu_cluster_pm_exit(void)
|
|
{
|
|
return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
|
|
|
|
#ifdef CONFIG_PM
|
|
static int cpu_pm_suspend(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = cpu_pm_enter();
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = cpu_cluster_pm_enter();
|
|
return ret;
|
|
}
|
|
|
|
static void cpu_pm_resume(void)
|
|
{
|
|
cpu_cluster_pm_exit();
|
|
cpu_pm_exit();
|
|
}
|
|
|
|
static struct syscore_ops cpu_pm_syscore_ops = {
|
|
.suspend = cpu_pm_suspend,
|
|
.resume = cpu_pm_resume,
|
|
};
|
|
|
|
static int cpu_pm_init(void)
|
|
{
|
|
register_syscore_ops(&cpu_pm_syscore_ops);
|
|
return 0;
|
|
}
|
|
core_initcall(cpu_pm_init);
|
|
#endif
|