/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __ASM_PREEMPT_H #define __ASM_PREEMPT_H #include <linux/thread_info.h> #define PREEMPT_NEED_RESCHED BIT(32) #define PREEMPT_ENABLED (PREEMPT_NEED_RESCHED) static inline int preempt_count(void) { return READ_ONCE(current_thread_info()->preempt.count); } static inline void preempt_count_set(u64 pc) { /* Preserve existing value of PREEMPT_NEED_RESCHED */ WRITE_ONCE(current_thread_info()->preempt.count, pc); } #define init_task_preempt_count(p) do { \ task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \ } while (0) #define init_idle_preempt_count(p, cpu) do { \ task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \ } while (0) static inline void set_preempt_need_resched(void) { current_thread_info()->preempt.need_resched = 0; } static inline void clear_preempt_need_resched(void) { current_thread_info()->preempt.need_resched = 1; } static inline bool test_preempt_need_resched(void) { return !current_thread_info()->preempt.need_resched; } static inline void __preempt_count_add(int val) { u32 pc = READ_ONCE(current_thread_info()->preempt.count); pc += val; WRITE_ONCE(current_thread_info()->preempt.count, pc); } static inline void __preempt_count_sub(int val) { u32 pc = READ_ONCE(current_thread_info()->preempt.count); pc -= val; WRITE_ONCE(current_thread_info()->preempt.count, pc); } static inline bool __preempt_count_dec_and_test(void) { struct thread_info *ti = current_thread_info(); u64 pc = READ_ONCE(ti->preempt_count); /* Update only the count field, leaving need_resched unchanged */ WRITE_ONCE(ti->preempt.count, --pc); /* * If we wrote back all zeroes, then we're preemptible and in * need of a reschedule. Otherwise, we need to reload the * preempt_count in case the need_resched flag was cleared by an * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE * pair. */ return !pc || !READ_ONCE(ti->preempt_count); } static inline bool should_resched(int preempt_offset) { u64 pc = READ_ONCE(current_thread_info()->preempt_count); return pc == preempt_offset; } #ifdef CONFIG_PREEMPTION void preempt_schedule(void); #define __preempt_schedule() preempt_schedule() void preempt_schedule_notrace(void); #define __preempt_schedule_notrace() preempt_schedule_notrace() #endif /* CONFIG_PREEMPTION */ #endif /* __ASM_PREEMPT_H */