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![Peter Zijlstra](/assets/img/avatar_default.png)
The recent cpuidle changes started triggering RCU splats on Juno development boards: | ============================= | WARNING: suspicious RCU usage | ----------------------------- | include/trace/events/ipi.h:19 suspicious rcu_dereference_check() usage! Fix cpuidle on ARM64: - ... by introducing a new 'is_rcu' flag to the cpuidle helpers & make ARM64 use it, as ARM64 wants to keep RCU active longer and wants to do the ct_cpuidle_enter()/exit() dance itself. - Also update the PSCI driver accordingly. - This also removes the last known RCU_NONIDLE() user as a bonus. Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/Y8Z31UbzG3LJgAXE@hirez.programming.kicks-ass.net --
352 lines
11 KiB
C
352 lines
11 KiB
C
/*
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* cpuidle.h - a generic framework for CPU idle power management
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*
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* (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
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* Shaohua Li <shaohua.li@intel.com>
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* Adam Belay <abelay@novell.com>
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*
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* This code is licenced under the GPL.
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*/
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#ifndef _LINUX_CPUIDLE_H
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#define _LINUX_CPUIDLE_H
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#include <linux/percpu.h>
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#include <linux/list.h>
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#include <linux/hrtimer.h>
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#include <linux/context_tracking.h>
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#define CPUIDLE_STATE_MAX 10
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#define CPUIDLE_NAME_LEN 16
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#define CPUIDLE_DESC_LEN 32
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struct module;
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struct cpuidle_device;
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struct cpuidle_driver;
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/****************************
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* CPUIDLE DEVICE INTERFACE *
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****************************/
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#define CPUIDLE_STATE_DISABLED_BY_USER BIT(0)
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#define CPUIDLE_STATE_DISABLED_BY_DRIVER BIT(1)
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struct cpuidle_state_usage {
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unsigned long long disable;
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unsigned long long usage;
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u64 time_ns;
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unsigned long long above; /* Number of times it's been too deep */
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unsigned long long below; /* Number of times it's been too shallow */
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unsigned long long rejected; /* Number of times idle entry was rejected */
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#ifdef CONFIG_SUSPEND
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unsigned long long s2idle_usage;
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unsigned long long s2idle_time; /* in US */
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#endif
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};
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struct cpuidle_state {
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char name[CPUIDLE_NAME_LEN];
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char desc[CPUIDLE_DESC_LEN];
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s64 exit_latency_ns;
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s64 target_residency_ns;
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unsigned int flags;
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unsigned int exit_latency; /* in US */
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int power_usage; /* in mW */
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unsigned int target_residency; /* in US */
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int (*enter) (struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index);
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int (*enter_dead) (struct cpuidle_device *dev, int index);
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/*
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* CPUs execute ->enter_s2idle with the local tick or entire timekeeping
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* suspended, so it must not re-enable interrupts at any point (even
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* temporarily) or attempt to change states of clock event devices.
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*
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* This callback may point to the same function as ->enter if all of
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* the above requirements are met by it.
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*/
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int (*enter_s2idle)(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index);
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};
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/* Idle State Flags */
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#define CPUIDLE_FLAG_NONE (0x00)
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#define CPUIDLE_FLAG_POLLING BIT(0) /* polling state */
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#define CPUIDLE_FLAG_COUPLED BIT(1) /* state applies to multiple cpus */
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#define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
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#define CPUIDLE_FLAG_UNUSABLE BIT(3) /* avoid using this state */
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#define CPUIDLE_FLAG_OFF BIT(4) /* disable this state by default */
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#define CPUIDLE_FLAG_TLB_FLUSHED BIT(5) /* idle-state flushes TLBs */
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#define CPUIDLE_FLAG_RCU_IDLE BIT(6) /* idle-state takes care of RCU */
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struct cpuidle_device_kobj;
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struct cpuidle_state_kobj;
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struct cpuidle_driver_kobj;
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struct cpuidle_device {
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unsigned int registered:1;
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unsigned int enabled:1;
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unsigned int poll_time_limit:1;
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unsigned int cpu;
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ktime_t next_hrtimer;
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int last_state_idx;
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u64 last_residency_ns;
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u64 poll_limit_ns;
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u64 forced_idle_latency_limit_ns;
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struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
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struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
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struct cpuidle_driver_kobj *kobj_driver;
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struct cpuidle_device_kobj *kobj_dev;
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struct list_head device_list;
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#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
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cpumask_t coupled_cpus;
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struct cpuidle_coupled *coupled;
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#endif
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};
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DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
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DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
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static __always_inline void ct_cpuidle_enter(void)
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{
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lockdep_assert_irqs_disabled();
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/*
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* Idle is allowed to (temporary) enable IRQs. It
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* will return with IRQs disabled.
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*
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* Trace IRQs enable here, then switch off RCU, and have
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* arch_cpu_idle() use raw_local_irq_enable(). Note that
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* ct_idle_enter() relies on lockdep IRQ state, so switch that
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* last -- this is very similar to the entry code.
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*/
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trace_hardirqs_on_prepare();
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lockdep_hardirqs_on_prepare();
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instrumentation_end();
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ct_idle_enter();
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lockdep_hardirqs_on(_RET_IP_);
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}
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static __always_inline void ct_cpuidle_exit(void)
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{
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/*
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* Carefully undo the above.
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*/
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lockdep_hardirqs_off(_RET_IP_);
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ct_idle_exit();
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instrumentation_begin();
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}
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/****************************
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* CPUIDLE DRIVER INTERFACE *
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****************************/
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struct cpuidle_driver {
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const char *name;
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struct module *owner;
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/* used by the cpuidle framework to setup the broadcast timer */
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unsigned int bctimer:1;
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/* states array must be ordered in decreasing power consumption */
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struct cpuidle_state states[CPUIDLE_STATE_MAX];
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int state_count;
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int safe_state_index;
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/* the driver handles the cpus in cpumask */
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struct cpumask *cpumask;
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/* preferred governor to switch at register time */
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const char *governor;
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};
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#ifdef CONFIG_CPU_IDLE
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extern void disable_cpuidle(void);
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extern bool cpuidle_not_available(struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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extern int cpuidle_select(struct cpuidle_driver *drv,
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struct cpuidle_device *dev,
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bool *stop_tick);
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extern int cpuidle_enter(struct cpuidle_driver *drv,
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struct cpuidle_device *dev, int index);
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extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
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extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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extern int cpuidle_register_driver(struct cpuidle_driver *drv);
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extern struct cpuidle_driver *cpuidle_get_driver(void);
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extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
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bool disable);
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extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
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extern int cpuidle_register_device(struct cpuidle_device *dev);
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extern void cpuidle_unregister_device(struct cpuidle_device *dev);
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extern int cpuidle_register(struct cpuidle_driver *drv,
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const struct cpumask *const coupled_cpus);
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extern void cpuidle_unregister(struct cpuidle_driver *drv);
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extern void cpuidle_pause_and_lock(void);
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extern void cpuidle_resume_and_unlock(void);
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extern void cpuidle_pause(void);
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extern void cpuidle_resume(void);
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extern int cpuidle_enable_device(struct cpuidle_device *dev);
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extern void cpuidle_disable_device(struct cpuidle_device *dev);
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extern int cpuidle_play_dead(void);
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extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
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static inline struct cpuidle_device *cpuidle_get_device(void)
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{return __this_cpu_read(cpuidle_devices); }
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#else
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static inline void disable_cpuidle(void) { }
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static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
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struct cpuidle_device *dev)
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{return true; }
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static inline int cpuidle_select(struct cpuidle_driver *drv,
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struct cpuidle_device *dev, bool *stop_tick)
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{return -ENODEV; }
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static inline int cpuidle_enter(struct cpuidle_driver *drv,
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struct cpuidle_device *dev, int index)
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{return -ENODEV; }
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static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
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static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
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struct cpuidle_device *dev)
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{return 0; }
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static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
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{return -ENODEV; }
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static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
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static inline void cpuidle_driver_state_disabled(struct cpuidle_driver *drv,
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int idx, bool disable) { }
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static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
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static inline int cpuidle_register_device(struct cpuidle_device *dev)
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{return -ENODEV; }
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static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
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static inline int cpuidle_register(struct cpuidle_driver *drv,
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const struct cpumask *const coupled_cpus)
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{return -ENODEV; }
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static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
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static inline void cpuidle_pause_and_lock(void) { }
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static inline void cpuidle_resume_and_unlock(void) { }
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static inline void cpuidle_pause(void) { }
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static inline void cpuidle_resume(void) { }
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static inline int cpuidle_enable_device(struct cpuidle_device *dev)
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{return -ENODEV; }
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static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
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static inline int cpuidle_play_dead(void) {return -ENODEV; }
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static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
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struct cpuidle_device *dev) {return NULL; }
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static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
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#endif
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#ifdef CONFIG_CPU_IDLE
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extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
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struct cpuidle_device *dev,
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u64 latency_limit_ns);
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extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
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#else
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static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
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struct cpuidle_device *dev,
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u64 latency_limit_ns)
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{return -ENODEV; }
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static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
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struct cpuidle_device *dev)
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{return -ENODEV; }
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static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
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{
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}
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#endif
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/* kernel/sched/idle.c */
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extern void sched_idle_set_state(struct cpuidle_state *idle_state);
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extern void default_idle_call(void);
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#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
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void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
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#else
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static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
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{
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}
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#endif
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#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
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void cpuidle_poll_state_init(struct cpuidle_driver *drv);
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#else
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static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
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#endif
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/******************************
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* CPUIDLE GOVERNOR INTERFACE *
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******************************/
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struct cpuidle_governor {
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char name[CPUIDLE_NAME_LEN];
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struct list_head governor_list;
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unsigned int rating;
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int (*enable) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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void (*disable) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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int (*select) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev,
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bool *stop_tick);
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void (*reflect) (struct cpuidle_device *dev, int index);
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};
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extern int cpuidle_register_governor(struct cpuidle_governor *gov);
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extern s64 cpuidle_governor_latency_req(unsigned int cpu);
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#define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, \
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idx, \
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state, \
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is_retention, is_rcu) \
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({ \
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int __ret = 0; \
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\
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if (!idx) { \
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cpu_do_idle(); \
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return idx; \
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} \
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\
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if (!is_retention) \
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__ret = cpu_pm_enter(); \
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if (!__ret) { \
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if (!is_rcu) \
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ct_cpuidle_enter(); \
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__ret = low_level_idle_enter(state); \
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if (!is_rcu) \
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ct_cpuidle_exit(); \
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if (!is_retention) \
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cpu_pm_exit(); \
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} \
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\
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__ret ? -1 : idx; \
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})
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#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0, 0)
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#define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1, 0)
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#define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 0)
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#define CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(low_level_idle_enter, idx, state) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 1)
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#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 0)
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#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(low_level_idle_enter, idx, state) \
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__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 1)
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#endif /* _LINUX_CPUIDLE_H */
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