arch/frv/include/asm/syscall.h

   1 /* syscall parameter access functions
   2  *
   3  * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11
  12 #ifndef _ASM_SYSCALL_H
  13 #define _ASM_SYSCALL_H
  14
  15 #include <linux/err.h>
  16 #include <asm/ptrace.h>
  17
  18 /*
  19  * Get the system call number or -1
  20  */
  21 static inline long syscall_get_nr(struct task_struct *task,
  22                                   struct pt_regs *regs)
  23 {
  24         return regs->syscallno;
  25 }
  26
  27 /*
  28  * Restore the clobbered GR8 register
  29  * (1st syscall arg was overwritten with syscall return or error)
  30  */
  31 static inline void syscall_rollback(struct task_struct *task,
  32                                     struct pt_regs *regs)
  33 {
  34         regs->gr8 = regs->orig_gr8;
  35 }
  36
  37 /*
  38  * See if the syscall return value is an error, returning it if it is and 0 if
  39  * not
  40  */
  41 static inline long syscall_get_error(struct task_struct *task,
  42                                      struct pt_regs *regs)
  43 {
  44         return IS_ERR_VALUE(regs->gr8) ? regs->gr8 : 0;
  45 }
  46
  47 /*
  48  * Get the syscall return value
  49  */
  50 static inline long syscall_get_return_value(struct task_struct *task,
  51                                             struct pt_regs *regs)
  52 {
  53         return regs->gr8;
  54 }
  55
  56 /*
  57  * Set the syscall return value
  58  */
  59 static inline void syscall_set_return_value(struct task_struct *task,
  60                                             struct pt_regs *regs,
  61                                             int error, long val)
  62 {
  63         if (error)
  64                 regs->gr8 = -error;
  65         else
  66                 regs->gr8 = val;
  67 }
  68
  69 /*
  70  * Retrieve the system call arguments
  71  */
  72 static inline void syscall_get_arguments(struct task_struct *task,
  73                                          struct pt_regs *regs,
  74                                          unsigned int i, unsigned int n,
  75                                          unsigned long *args)
  76 {
  77         /*
  78          * Do this simply for now. If we need to start supporting
  79          * fetching arguments from arbitrary indices, this will need some
  80          * extra logic. Presently there are no in-tree users that depend
  81          * on this behaviour.
  82          */
  83         BUG_ON(i);
  84
  85         /* Argument pattern is: GR8, GR9, GR10, GR11, GR12, GR13 */
  86         switch (n) {
  87         case 6: args[5] = regs->gr13;
  88         case 5: args[4] = regs->gr12;
  89         case 4: args[3] = regs->gr11;
  90         case 3: args[2] = regs->gr10;
  91         case 2: args[1] = regs->gr9;
  92         case 1: args[0] = regs->gr8;
  93                 break;
  94         default:
  95                 BUG();
  96         }
  97 }
  98
  99 /*
 100  * Alter the system call arguments
 101  */
 102 static inline void syscall_set_arguments(struct task_struct *task,
 103                                          struct pt_regs *regs,
 104                                          unsigned int i, unsigned int n,
 105                                          const unsigned long *args)
 106 {
 107         /* Same note as above applies */
 108         BUG_ON(i);
 109
 110         switch (n) {
 111         case 6: regs->gr13 = args[5];
 112         case 5: regs->gr12 = args[4];
 113         case 4: regs->gr11 = args[3];
 114         case 3: regs->gr10 = args[2];
 115         case 2: regs->gr9  = args[1];
 116         case 1: regs->gr8  = args[0];
 117                 break;
 118         default:
 119                 BUG();
 120         }
 121 }
 122
 123 #endif /* _ASM_SYSCALL_H */