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kernel/linux-imx6_3.14.28/include/asm-generic/preempt.h 1.98 KB
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  #ifndef __ASM_PREEMPT_H
  #define __ASM_PREEMPT_H
  
  #include <linux/thread_info.h>
  
  #define PREEMPT_ENABLED	(0)
  
  static __always_inline int preempt_count(void)
  {
  	return current_thread_info()->preempt_count;
  }
  
  static __always_inline int *preempt_count_ptr(void)
  {
  	return &current_thread_info()->preempt_count;
  }
  
  static __always_inline void preempt_count_set(int pc)
  {
  	*preempt_count_ptr() = pc;
  }
  
  /*
   * must be macros to avoid header recursion hell
   */
  #define task_preempt_count(p) \
  	(task_thread_info(p)->preempt_count & ~PREEMPT_NEED_RESCHED)
  
  #define init_task_preempt_count(p) do { \
  	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
  } while (0)
  
  #define init_idle_preempt_count(p, cpu) do { \
  	task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
  } while (0)
  
  static __always_inline void set_preempt_need_resched(void)
  {
  }
  
  static __always_inline void clear_preempt_need_resched(void)
  {
  }
  
  static __always_inline bool test_preempt_need_resched(void)
  {
  	return false;
  }
  
  /*
   * The various preempt_count add/sub methods
   */
  
  static __always_inline void __preempt_count_add(int val)
  {
  	*preempt_count_ptr() += val;
  }
  
  static __always_inline void __preempt_count_sub(int val)
  {
  	*preempt_count_ptr() -= val;
  }
  
  static __always_inline bool __preempt_count_dec_and_test(void)
  {
  	/*
  	 * Because of load-store architectures cannot do per-cpu atomic
  	 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
  	 * lost.
  	 */
  	return !--*preempt_count_ptr() && tif_need_resched();
  }
  
  /*
   * Returns true when we need to resched and can (barring IRQ state).
   */
  static __always_inline bool should_resched(void)
  {
  	return unlikely(!preempt_count() && tif_need_resched());
  }
  
  #ifdef CONFIG_PREEMPT
  extern asmlinkage void preempt_schedule(void);
  #define __preempt_schedule() preempt_schedule()
  
  #ifdef CONFIG_CONTEXT_TRACKING
  extern asmlinkage void preempt_schedule_context(void);
  #define __preempt_schedule_context() preempt_schedule_context()
  #endif
  #endif /* CONFIG_PREEMPT */
  
  #endif /* __ASM_PREEMPT_H */