/*
   * Access to user system call parameters and results
   *

   * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.

   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions
   * of the GNU General Public License v.2.
   *
   * See asm-generic/syscall.h for descriptions of what we must do here.
   */

  #ifndef _ASM_X86_SYSCALL_H
  #define _ASM_X86_SYSCALL_H

  
  #include <linux/sched.h>

  #include <linux/err.h>

  #include <asm/asm-offsets.h>	/* For NR_syscalls */

  extern const unsigned long sys_call_table[];

  /*
   * Only the low 32 bits of orig_ax are meaningful, so we return int.
   * This importantly ignores the high bits on 64-bit, so comparisons
   * sign-extend the low 32 bits.
   */
  static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)

  {

  	return regs->orig_ax;
  }
  
  static inline void syscall_rollback(struct task_struct *task,
  				    struct pt_regs *regs)
  {
  	regs->ax = regs->orig_ax;
  }
  
  static inline long syscall_get_error(struct task_struct *task,
  				     struct pt_regs *regs)
  {
  	unsigned long error = regs->ax;
  #ifdef CONFIG_IA32_EMULATION
  	/*
  	 * TS_COMPAT is set for 32-bit syscall entries and then
  	 * remains set until we return to user mode.
  	 */
  	if (task_thread_info(task)->status & TS_COMPAT)
  		/*
  		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  		 * and will match correctly in comparisons.
  		 */
  		error = (long) (int) error;
  #endif

  	return IS_ERR_VALUE(error) ? error : 0;

  }
  
  static inline long syscall_get_return_value(struct task_struct *task,
  					    struct pt_regs *regs)
  {
  	return regs->ax;
  }
  
  static inline void syscall_set_return_value(struct task_struct *task,
  					    struct pt_regs *regs,
  					    int error, long val)
  {
  	regs->ax = (long) error ?: val;
  }
  
  #ifdef CONFIG_X86_32
  
  static inline void syscall_get_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 unsigned long *args)
  {
  	BUG_ON(i + n > 6);
  	memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  }
  
  static inline void syscall_set_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 const unsigned long *args)
  {
  	BUG_ON(i + n > 6);
  	memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  }
  
  #else	 /* CONFIG_X86_64 */
  
  static inline void syscall_get_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 unsigned long *args)
  {
  # ifdef CONFIG_IA32_EMULATION
  	if (task_thread_info(task)->status & TS_COMPAT)

  		switch (i) {
  		case 0:

  			if (!n--) break;

  			*args++ = regs->bx;
  		case 1:

  			if (!n--) break;

  			*args++ = regs->cx;
  		case 2:

  			if (!n--) break;

  			*args++ = regs->dx;

  		case 3:
  			if (!n--) break;

  			*args++ = regs->si;
  		case 4:

  			if (!n--) break;

  			*args++ = regs->di;
  		case 5:

  			if (!n--) break;

  			*args++ = regs->bp;
  		case 6:

  			if (!n--) break;
  		default:
  			BUG();
  			break;
  		}
  	else
  # endif

  		switch (i) {
  		case 0:

  			if (!n--) break;

  			*args++ = regs->di;
  		case 1:

  			if (!n--) break;

  			*args++ = regs->si;
  		case 2:

  			if (!n--) break;

  			*args++ = regs->dx;

  		case 3:
  			if (!n--) break;

  			*args++ = regs->r10;
  		case 4:

  			if (!n--) break;

  			*args++ = regs->r8;
  		case 5:

  			if (!n--) break;

  			*args++ = regs->r9;
  		case 6:

  			if (!n--) break;
  		default:
  			BUG();
  			break;
  		}
  }
  
  static inline void syscall_set_arguments(struct task_struct *task,
  					 struct pt_regs *regs,
  					 unsigned int i, unsigned int n,
  					 const unsigned long *args)
  {
  # ifdef CONFIG_IA32_EMULATION
  	if (task_thread_info(task)->status & TS_COMPAT)

  		switch (i) {
  		case 0:

  			if (!n--) break;

  			regs->bx = *args++;
  		case 1:

  			if (!n--) break;

  			regs->cx = *args++;
  		case 2:

  			if (!n--) break;

  			regs->dx = *args++;

  		case 3:
  			if (!n--) break;

  			regs->si = *args++;
  		case 4:

  			if (!n--) break;

  			regs->di = *args++;
  		case 5:

  			if (!n--) break;

  			regs->bp = *args++;
  		case 6:

  			if (!n--) break;
  		default:
  			BUG();

  			break;

  		}
  	else
  # endif

  		switch (i) {
  		case 0:

  			if (!n--) break;

  			regs->di = *args++;
  		case 1:

  			if (!n--) break;

  			regs->si = *args++;
  		case 2:

  			if (!n--) break;

  			regs->dx = *args++;

  		case 3:
  			if (!n--) break;

  			regs->r10 = *args++;
  		case 4:

  			if (!n--) break;

  			regs->r8 = *args++;
  		case 5:

  			if (!n--) break;

  			regs->r9 = *args++;
  		case 6:

  			if (!n--) break;
  		default:
  			BUG();

  			break;

  		}
  }
  
  #endif	/* CONFIG_X86_32 */

  #endif	/* _ASM_X86_SYSCALL_H */