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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef __ASM_PREEMPT_H
- #define __ASM_PREEMPT_H
- #include <linux/jump_label.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);
- void preempt_schedule_notrace(void);
- #ifdef CONFIG_PREEMPT_DYNAMIC
- DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
- void dynamic_preempt_schedule(void);
- #define __preempt_schedule() dynamic_preempt_schedule()
- void dynamic_preempt_schedule_notrace(void);
- #define __preempt_schedule_notrace() dynamic_preempt_schedule_notrace()
- #else /* CONFIG_PREEMPT_DYNAMIC */
- #define __preempt_schedule() preempt_schedule()
- #define __preempt_schedule_notrace() preempt_schedule_notrace()
- #endif /* CONFIG_PREEMPT_DYNAMIC */
- #endif /* CONFIG_PREEMPTION */
- #endif /* __ASM_PREEMPT_H */
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