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
  22 static 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
  41 static inline void syscall_rollback(struct task_struct *task,
  42                                     struct pt_regs *regs)
  43 {
  44         /* do nothing */
  45 }
  46
  47 static 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
  54 static 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
  60 static 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
  67 static 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
  83 static 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 */
 102 extern const void *sys_call_table[];
 103
 104 #endif  /* _ASM_METAG_SYSCALL_H */