Logo Search packages:      
Sourcecode: linux version File versions  Download package

syscall.h

/* 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 */

Generated by  Doxygen 1.6.0   Back to index