LXR linux/arch/metag/include/asm/syscall.h

   1/*
   2 * Access to user system call parameters and results
   3 *
   4 * Copyright (C) 2008 Imagination Technologies Ltd.
   5 *
   6 * This copyrighted material is made available to anyone wishing to use,
   7 * modify, copy, or redistribute it subject to the terms and conditions
   8 * of the GNU General Public License v.2.
   9 *
  10 * See asm-generic/syscall.h for descriptions of what we must do here.
  11 */
  12
  13#ifndef _ASM_METAG_SYSCALL_H
  14#define _ASM_METAG_SYSCALL_H
  15
  16#include <linux/sched.h>
  17#include <linux/err.h>
  18#include <linux/uaccess.h>
  19
  20#include <asm/switch.h>
  21
  22static inline long syscall_get_nr(struct task_struct *task,
  23                                  struct pt_regs *regs)
  24{
  25        unsigned long insn;
  26
  27        /*
  28         * FIXME there's no way to find out how we got here other than to
  29         * examine the memory at the PC to see if it is a syscall
  30         * SWITCH instruction.
  31         */
  32        if (get_user(insn, (unsigned long *)(regs->ctx.CurrPC - 4)))
  33                return -1;
  34
  35        if (insn == __METAG_SW_ENCODING(SYS))
  36                return regs->ctx.DX[0].U1;
  37        else
  38                return -1L;
  39}
  40
  41static inline void syscall_rollback(struct task_struct *task,
  42                                    struct pt_regs *regs)
  43{
  44        /* do nothing */
  45}
  46
  47static inline long syscall_get_error(struct task_struct *task,
  48                                     struct pt_regs *regs)
  49{
  50        unsigned long error = regs->ctx.DX[0].U0;
  51        return IS_ERR_VALUE(error) ? error : 0;
  52}
  53
  54static inline long syscall_get_return_value(struct task_struct *task,
  55                                            struct pt_regs *regs)
  56{
  57        return regs->ctx.DX[0].U0;
  58}
  59
  60static inline void syscall_set_return_value(struct task_struct *task,
  61                                            struct pt_regs *regs,
  62                                            int error, long val)
  63{
  64        regs->ctx.DX[0].U0 = (long) error ?: val;
  65}
  66
  67static inline void syscall_get_arguments(struct task_struct *task,
  68                                         struct pt_regs *regs,
  69                                         unsigned int i, unsigned int n,
  70                                         unsigned long *args)
  71{
  72        unsigned int reg, j;
  73        BUG_ON(i + n > 6);
  74
  75        for (j = i, reg = 6 - i; j < (i + n); j++, reg--) {
  76                if (reg % 2)
  77                        args[j] = regs->ctx.DX[(reg + 1) / 2].U0;
  78                else
  79                        args[j] = regs->ctx.DX[reg / 2].U1;
  80        }
  81}
  82
  83static inline void syscall_set_arguments(struct task_struct *task,
  84                                         struct pt_regs *regs,
  85                                         unsigned int i, unsigned int n,
  86                                         const unsigned long *args)
  87{
  88        unsigned int reg;
  89        BUG_ON(i + n > 6);
  90
  91        for (reg = 6 - i; i < (i + n); i++, reg--) {
  92                if (reg % 2)
  93                        regs->ctx.DX[(reg + 1) / 2].U0 = args[i];
  94                else
  95                        regs->ctx.DX[reg / 2].U1 = args[i];
  96        }
  97}
  98
  99#define NR_syscalls __NR_syscalls
 100
 101/* generic syscall table */
 102extern const void *sys_call_table[];
 103
 104#endif  /* _ASM_METAG_SYSCALL_H */
 105