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kernel/linux-rt-4.4.41/arch/frv/include/asm/syscall.h 2.73 KB
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  /* syscall parameter access functions
   *
   * Copyright (C) 2009 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_SYSCALL_H
  #define _ASM_SYSCALL_H
  
  #include <linux/err.h>
  #include <asm/ptrace.h>
  
  /*
   * Get the system call number or -1
   */
  static inline long syscall_get_nr(struct task_struct *task,
  				  struct pt_regs *regs)
  {
  	return regs->syscallno;
  }
  
  /*
   * Restore the clobbered GR8 register
   * (1st syscall arg was overwritten with syscall return or error)
   */
  static inline void syscall_rollback(struct task_struct *task,
  				    struct pt_regs *regs)
  {
  	regs->gr8 = regs->orig_gr8;
  }
  
  /*
   * See if the syscall return value is an error, returning it if it is and 0 if
   * not
   */
  static inline long syscall_get_error(struct task_struct *task,
  				     struct pt_regs *regs)
  {
  	return IS_ERR_VALUE(regs->gr8) ? regs->gr8 : 0;
  }
  
  /*
   * Get the syscall return value
   */
  static inline long syscall_get_return_value(struct task_struct *task,
  					    struct pt_regs *regs)
  {
  	return regs->gr8;
  }
  
  /*
   * Set the syscall return value
   */
  static inline void syscall_set_return_value(struct task_struct *task,
  					    struct pt_regs *regs,
  					    int error, long val)
  {
  	if (error)
  		regs->gr8 = -error;
  	else
  		regs->gr8 = val;
  }
  
  /*
   * Retrieve the system call arguments
   */
  static inline void syscall_get_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 unsigned long *args)
  {
  	/*
  	 * Do this simply for now. If we need to start supporting
  	 * fetching arguments from arbitrary indices, this will need some
  	 * extra logic. Presently there are no in-tree users that depend
  	 * on this behaviour.
  	 */
  	BUG_ON(i);
  
  	/* Argument pattern is: GR8, GR9, GR10, GR11, GR12, GR13 */
  	switch (n) {
  	case 6: args[5] = regs->gr13;
  	case 5: args[4] = regs->gr12;
  	case 4: args[3] = regs->gr11;
  	case 3: args[2] = regs->gr10;
  	case 2: args[1] = regs->gr9;
  	case 1:	args[0] = regs->gr8;
  		break;
  	default:
  		BUG();
  	}
  }
  
  /*
   * Alter the system call arguments
   */
  static inline void syscall_set_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 const unsigned long *args)
  {
  	/* Same note as above applies */
  	BUG_ON(i);
  
  	switch (n) {
  	case 6: regs->gr13 = args[5];
  	case 5: regs->gr12 = args[4];
  	case 4: regs->gr11 = args[3];
  	case 3: regs->gr10 = args[2];
  	case 2: regs->gr9  = args[1];
  	case 1: regs->gr8  = args[0];
  		break;
  	default:
  		BUG();
  	}
  }
  
  #endif /* _ASM_SYSCALL_H */