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kernel/linux-rt-4.4.41/arch/mn10300/include/asm/switch_to.h 1.47 KB
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  /* MN10300 task switching definitions
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public Licence
   * as published by the Free Software Foundation; either version
   * 2 of the Licence, or (at your option) any later version.
   */
  #ifndef _ASM_SWITCH_TO_H
  #define _ASM_SWITCH_TO_H
  
  #include <asm/barrier.h>
  
  struct task_struct;
  struct thread_struct;
  
  #if !defined(CONFIG_LAZY_SAVE_FPU)
  struct fpu_state_struct;
  extern asmlinkage void fpu_save(struct fpu_state_struct *);
  #define switch_fpu(prev, next)						\
  	do {								\
  		if ((prev)->thread.fpu_flags & THREAD_HAS_FPU) {	\
  			(prev)->thread.fpu_flags &= ~THREAD_HAS_FPU;	\
  			(prev)->thread.uregs->epsw &= ~EPSW_FE;		\
  			fpu_save(&(prev)->thread.fpu_state);		\
  		}							\
  	} while (0)
  #else
  #define switch_fpu(prev, next) do {} while (0)
  #endif
  
  /* context switching is now performed out-of-line in switch_to.S */
  extern asmlinkage
  struct task_struct *__switch_to(struct thread_struct *prev,
  				struct thread_struct *next,
  				struct task_struct *prev_task);
  
  #define switch_to(prev, next, last)					\
  do {									\
  	switch_fpu(prev, next);						\
  	current->thread.wchan = (u_long) __builtin_return_address(0);	\
  	(last) = __switch_to(&(prev)->thread, &(next)->thread, (prev));	\
  	mb();								\
  	current->thread.wchan = 0;					\
  } while (0)
  
  #endif /* _ASM_SWITCH_TO_H */