include/asm-s390/ioctl.h

   1 /*
   2  *  include/asm-s390/ioctl.h
   3  *
   4  *  S390 version
   5  *
   6  *  Derived from "include/asm-i386/ioctl.h"
   7  */
   8
   9 #ifndef _S390_IOCTL_H
  10 #define _S390_IOCTL_H
  11
  12 /* ioctl command encoding: 32 bits total, command in lower 16 bits,
  13  * size of the parameter structure in the lower 14 bits of the
  14  * upper 16 bits.
  15  * Encoding the size of the parameter structure in the ioctl request
  16  * is useful for catching programs compiled with old versions
  17  * and to avoid overwriting user space outside the user buffer area.
  18  * The highest 2 bits are reserved for indicating the ``access mode''.
  19  * NOTE: This limits the max parameter size to 16kB -1 !
  20  */
  21
  22 /*
  23  * The following is for compatibility across the various Linux
  24  * platforms.  The i386 ioctl numbering scheme doesn't really enforce
  25  * a type field.  De facto, however, the top 8 bits of the lower 16
  26  * bits are indeed used as a type field, so we might just as well make
  27  * this explicit here.  Please be sure to use the decoding macros
  28  * below from now on.
  29  */
  30 #define _IOC_NRBITS     8
  31 #define _IOC_TYPEBITS   8
  32 #define _IOC_SIZEBITS   14
  33 #define _IOC_DIRBITS    2
  34
  35 #define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  36 #define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  37 #define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  38 #define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  39
  40 #define _IOC_NRSHIFT    0
  41 #define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  42 #define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  43 #define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  44
  45 /*
  46  * Direction bits.
  47  */
  48 #define _IOC_NONE       0U
  49 #define _IOC_WRITE      1U
  50 #define _IOC_READ       2U
  51
  52 #define _IOC(dir,type,nr,size) \
  53         (((dir)  << _IOC_DIRSHIFT) | \
  54          ((type) << _IOC_TYPESHIFT) | \
  55          ((nr)   << _IOC_NRSHIFT) | \
  56          ((size) << _IOC_SIZESHIFT))
  57
  58 /* provoke compile error for invalid uses of size argument */
  59 extern unsigned long __invalid_size_argument_for_IOC;
  60 #define _IOC_TYPECHECK(t) \
  61         ((sizeof(t) == sizeof(t[1]) && \
  62           sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
  63           sizeof(t) : __invalid_size_argument_for_IOC)
  64
  65 /* used to create numbers */
  66 #define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  67 #define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
  68 #define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  69 #define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  70 #define _IOR_BAD(type,nr,size)  _IOC(_IOC_READ,(type),(nr),sizeof(size))
  71 #define _IOW_BAD(type,nr,size)  _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  72 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  73
  74 /* used to decode ioctl numbers.. */
  75 #define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  76 #define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  77 #define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  78 #define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  79
  80 /* ...and for the drivers/sound files... */
  81
  82 #define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  83 #define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  84 #define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  85 #define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  86 #define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  87
  88 #endif /* _S390_IOCTL_H */