1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_SCHED_IDLE_H 3#define _LINUX_SCHED_IDLE_H 4 5#include <linux/sched.h> 6 7enum cpu_idle_type { 8 CPU_IDLE, 9 CPU_NOT_IDLE, 10 CPU_NEWLY_IDLE, 11 CPU_MAX_IDLE_TYPES 12}; 13 14#ifdef CONFIG_SMP 15extern void wake_up_if_idle(int cpu); 16#else 17static inline void wake_up_if_idle(int cpu) { } 18#endif 19 20/* 21 * Idle thread specific functions to determine the need_resched 22 * polling state. 23 */ 24#ifdef TIF_POLLING_NRFLAG 25 26#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H 27 28static __always_inline void __current_set_polling(void) 29{ 30 arch_set_bit(TIF_POLLING_NRFLAG, 31 (unsigned long *)(¤t_thread_info()->flags)); 32} 33 34static __always_inline void __current_clr_polling(void) 35{ 36 arch_clear_bit(TIF_POLLING_NRFLAG, 37 (unsigned long *)(¤t_thread_info()->flags)); 38} 39 40#else 41 42static __always_inline void __current_set_polling(void) 43{ 44 set_bit(TIF_POLLING_NRFLAG, 45 (unsigned long *)(¤t_thread_info()->flags)); 46} 47 48static __always_inline void __current_clr_polling(void) 49{ 50 clear_bit(TIF_POLLING_NRFLAG, 51 (unsigned long *)(¤t_thread_info()->flags)); 52} 53 54#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */ 55 56static __always_inline bool __must_check current_set_polling_and_test(void) 57{ 58 __current_set_polling(); 59 60 /* 61 * Polling state must be visible before we test NEED_RESCHED, 62 * paired by resched_curr() 63 */ 64 smp_mb__after_atomic(); 65 66 return unlikely(tif_need_resched()); 67} 68 69static __always_inline bool __must_check current_clr_polling_and_test(void) 70{ 71 __current_clr_polling(); 72 73 /* 74 * Polling state must be visible before we test NEED_RESCHED, 75 * paired by resched_curr() 76 */ 77 smp_mb__after_atomic(); 78 79 return unlikely(tif_need_resched()); 80} 81 82#else 83static inline void __current_set_polling(void) { } 84static inline void __current_clr_polling(void) { } 85 86static inline bool __must_check current_set_polling_and_test(void) 87{ 88 return unlikely(tif_need_resched()); 89} 90static inline bool __must_check current_clr_polling_and_test(void) 91{ 92 return unlikely(tif_need_resched()); 93} 94#endif 95 96static __always_inline void current_clr_polling(void) 97{ 98 __current_clr_polling(); 99 100 /* 101 * Ensure we check TIF_NEED_RESCHED after we clear the polling bit. 102 * Once the bit is cleared, we'll get IPIs with every new 103 * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also 104 * fold. 105 */ 106 smp_mb(); /* paired with resched_curr() */ 107 108 preempt_fold_need_resched(); 109} 110 111#endif /* _LINUX_SCHED_IDLE_H */ 112