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linux-next/include/linux/cpuidle.h
Rafael J. Wysocki 2ab80d46fe cpuidle: Use s64 as exit_latency_ns and target_residency_ns data type 
Subsequent changes will cause the exit_latency_ns and target_residency_ns
fields in struct cpuidle_state to be used in computations in which data
type conversions to u64 may turn a negative number close to zero into
a verly large positive number leading to incorrect results.

In preparation for that, change the data type of the fields mentioned
above to s64, but ensure that they will not be negative themselves.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-04-07 19:26:44 +02:00

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/*
* cpuidle.h - a generic framework for CPU idle power management
*
* (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* Shaohua Li <shaohua.li@intel.com>
* Adam Belay <abelay@novell.com>
*
* This code is licenced under the GPL.
*/
#ifndef _LINUX_CPUIDLE_H
#define _LINUX_CPUIDLE_H
#include <linux/percpu.h>
#include <linux/list.h>
#include <linux/hrtimer.h>
#define CPUIDLE_STATE_MAX 10
#define CPUIDLE_NAME_LEN 16
#define CPUIDLE_DESC_LEN 32
struct module;
struct cpuidle_device;
struct cpuidle_driver;
/****************************
* CPUIDLE DEVICE INTERFACE *
****************************/
#define CPUIDLE_STATE_DISABLED_BY_USER BIT(0)
#define CPUIDLE_STATE_DISABLED_BY_DRIVER BIT(1)
struct cpuidle_state_usage {
unsigned long long disable;
unsigned long long usage;
u64 time_ns;
unsigned long long above; /* Number of times it's been too deep */
unsigned long long below; /* Number of times it's been too shallow */
unsigned long long rejected; /* Number of times idle entry was rejected */
#ifdef CONFIG_SUSPEND
unsigned long long s2idle_usage;
unsigned long long s2idle_time; /* in US */
#endif
};
struct cpuidle_state {
char name[CPUIDLE_NAME_LEN];
char desc[CPUIDLE_DESC_LEN];
s64 exit_latency_ns;
s64 target_residency_ns;
unsigned int flags;
unsigned int exit_latency; /* in US */
int power_usage; /* in mW */
unsigned int target_residency; /* in US */
int (*enter) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
int (*enter_dead) (struct cpuidle_device *dev, int index);
/*
* CPUs execute ->enter_s2idle with the local tick or entire timekeeping
* suspended, so it must not re-enable interrupts at any point (even
* temporarily) or attempt to change states of clock event devices.
*
* This callback may point to the same function as ->enter if all of
* the above requirements are met by it.
*/
int (*enter_s2idle)(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
};
/* Idle State Flags */
#define CPUIDLE_FLAG_NONE (0x00)
#define CPUIDLE_FLAG_POLLING BIT(0) /* polling state */
#define CPUIDLE_FLAG_COUPLED BIT(1) /* state applies to multiple cpus */
#define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
#define CPUIDLE_FLAG_UNUSABLE BIT(3) /* avoid using this state */
#define CPUIDLE_FLAG_OFF BIT(4) /* disable this state by default */
#define CPUIDLE_FLAG_TLB_FLUSHED BIT(5) /* idle-state flushes TLBs */
#define CPUIDLE_FLAG_RCU_IDLE BIT(6) /* idle-state takes care of RCU */
struct cpuidle_device_kobj;
struct cpuidle_state_kobj;
struct cpuidle_driver_kobj;
struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
unsigned int poll_time_limit:1;
unsigned int cpu;
ktime_t next_hrtimer;
int last_state_idx;
u64 last_residency_ns;
u64 poll_limit_ns;
u64 forced_idle_latency_limit_ns;
struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
struct cpuidle_driver_kobj *kobj_driver;
struct cpuidle_device_kobj *kobj_dev;
struct list_head device_list;
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
cpumask_t coupled_cpus;
struct cpuidle_coupled *coupled;
#endif
};
DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);
/****************************
* CPUIDLE DRIVER INTERFACE *
****************************/
struct cpuidle_driver {
const char *name;
struct module *owner;
/* used by the cpuidle framework to setup the broadcast timer */
unsigned int bctimer:1;
/* states array must be ordered in decreasing power consumption */
struct cpuidle_state states[CPUIDLE_STATE_MAX];
int state_count;
int safe_state_index;
/* the driver handles the cpus in cpumask */
struct cpumask *cpumask;
/* preferred governor to switch at register time */
const char *governor;
};
#ifdef CONFIG_CPU_IDLE
extern void disable_cpuidle(void);
extern bool cpuidle_not_available(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
extern int cpuidle_select(struct cpuidle_driver *drv,
struct cpuidle_device *dev,
bool *stop_tick);
extern int cpuidle_enter(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index);
extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern struct cpuidle_driver *cpuidle_get_driver(void);
extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
bool disable);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);
extern int cpuidle_register(struct cpuidle_driver *drv,
const struct cpumask *const coupled_cpus);
extern void cpuidle_unregister(struct cpuidle_driver *drv);
extern void cpuidle_pause_and_lock(void);
extern void cpuidle_resume_and_unlock(void);
extern void cpuidle_pause(void);
extern void cpuidle_resume(void);
extern int cpuidle_enable_device(struct cpuidle_device *dev);
extern void cpuidle_disable_device(struct cpuidle_device *dev);
extern int cpuidle_play_dead(void);
extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
static inline struct cpuidle_device *cpuidle_get_device(void)
{return __this_cpu_read(cpuidle_devices); }
#else
static inline void disable_cpuidle(void) { }
static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{return true; }
static inline int cpuidle_select(struct cpuidle_driver *drv,
struct cpuidle_device *dev, bool *stop_tick)
{return -ENODEV; }
static inline int cpuidle_enter(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index)
{return -ENODEV; }
static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{return 0; }
static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
static inline void cpuidle_driver_state_disabled(struct cpuidle_driver *drv,
int idx, bool disable) { }
static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
static inline int cpuidle_register_device(struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
static inline int cpuidle_register(struct cpuidle_driver *drv,
const struct cpumask *const coupled_cpus)
{return -ENODEV; }
static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
static inline void cpuidle_pause_and_lock(void) { }
static inline void cpuidle_resume_and_unlock(void) { }
static inline void cpuidle_pause(void) { }
static inline void cpuidle_resume(void) { }
static inline int cpuidle_enable_device(struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
static inline int cpuidle_play_dead(void) {return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
struct cpuidle_device *dev) {return NULL; }
static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
#endif
#ifdef CONFIG_CPU_IDLE
extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev,
u64 latency_limit_ns);
extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
#else
static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev,
u64 latency_limit_ns)
{return -ENODEV; }
static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
{
}
#endif
/* kernel/sched/idle.c */
extern void sched_idle_set_state(struct cpuidle_state *idle_state);
extern void default_idle_call(void);
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
#else
static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
{
}
#endif
#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
void cpuidle_poll_state_init(struct cpuidle_driver *drv);
#else
static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
#endif
/******************************
* CPUIDLE GOVERNOR INTERFACE *
******************************/
struct cpuidle_governor {
char name[CPUIDLE_NAME_LEN];
struct list_head governor_list;
unsigned int rating;
int (*enable) (struct cpuidle_driver *drv,
struct cpuidle_device *dev);
void (*disable) (struct cpuidle_driver *drv,
struct cpuidle_device *dev);
int (*select) (struct cpuidle_driver *drv,
struct cpuidle_device *dev,
bool *stop_tick);
void (*reflect) (struct cpuidle_device *dev, int index);
};
extern int cpuidle_register_governor(struct cpuidle_governor *gov);
extern s64 cpuidle_governor_latency_req(unsigned int cpu);
#define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, \
idx, \
state, \
is_retention) \
({ \
int __ret = 0; \
\
if (!idx) { \
cpu_do_idle(); \
return idx; \
} \
\
if (!is_retention) \
__ret = cpu_pm_enter(); \
if (!__ret) { \
__ret = low_level_idle_enter(state); \
if (!is_retention) \
cpu_pm_exit(); \
} \
\
__ret ? -1 : idx; \
})
#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx) \
__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0)
#define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx) \
__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1)
#define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state) \
__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0)
#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
__CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1)
#endif /* _LINUX_CPUIDLE_H */
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