fs/xfs/xfs_arch.h

   1 /*
   2  * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32 #ifndef __XFS_ARCH_H__
  33 #define __XFS_ARCH_H__
  34
  35 #ifndef XFS_BIG_INUMS
  36 # error XFS_BIG_INUMS must be defined true or false
  37 #endif
  38
  39 #ifdef __KERNEL__
  40
  41 #include <asm/byteorder.h>
  42
  43 #ifdef __LITTLE_ENDIAN
  44 # define __BYTE_ORDER   __LITTLE_ENDIAN
  45 #endif
  46 #ifdef __BIG_ENDIAN
  47 # define __BYTE_ORDER   __BIG_ENDIAN
  48 #endif
  49
  50 #endif  /* __KERNEL__ */
  51
  52 /* do we need conversion? */
  53
  54 #define ARCH_NOCONVERT 1
  55 #if __BYTE_ORDER == __LITTLE_ENDIAN
  56 # define ARCH_CONVERT   0
  57 #else
  58 # define ARCH_CONVERT   ARCH_NOCONVERT
  59 #endif
  60
  61 /* generic swapping macros */
  62
  63 #ifndef HAVE_SWABMACROS
  64 #define INT_SWAP16(type,var) ((typeof(type))(__swab16((__u16)(var))))
  65 #define INT_SWAP32(type,var) ((typeof(type))(__swab32((__u32)(var))))
  66 #define INT_SWAP64(type,var) ((typeof(type))(__swab64((__u64)(var))))
  67 #endif
  68
  69 #define INT_SWAP(type, var) \
  70     ((sizeof(type) == 8) ? INT_SWAP64(type,var) : \
  71     ((sizeof(type) == 4) ? INT_SWAP32(type,var) : \
  72     ((sizeof(type) == 2) ? INT_SWAP16(type,var) : \
  73     (var))))
  74
  75 /*
  76  * get and set integers from potentially unaligned locations
  77  */
  78
  79 #define INT_GET_UNALIGNED_16_BE(pointer) \
  80    ((__u16)((((__u8*)(pointer))[0] << 8) | (((__u8*)(pointer))[1])))
  81 #define INT_SET_UNALIGNED_16_BE(pointer,value) \
  82     { \
  83         ((__u8*)(pointer))[0] = (((value) >> 8) & 0xff); \
  84         ((__u8*)(pointer))[1] = (((value)     ) & 0xff); \
  85     }
  86
  87 /* define generic INT_ macros */
  88
  89 #define INT_GET(reference,arch) \
  90     (((arch) == ARCH_NOCONVERT) \
  91         ? \
  92             (reference) \
  93         : \
  94             INT_SWAP((reference),(reference)) \
  95     )
  96
  97 /* does not return a value */
  98 #define INT_SET(reference,arch,valueref) \
  99     (__builtin_constant_p(valueref) ? \
 100         (void)( (reference) = ( ((arch) != ARCH_NOCONVERT) ? (INT_SWAP((reference),(valueref))) : (valueref)) ) : \
 101         (void)( \
 102             ((reference) = (valueref)), \
 103             ( ((arch) != ARCH_NOCONVERT) ? (reference) = INT_SWAP((reference),(reference)) : 0 ) \
 104         ) \
 105     )
 106
 107 /* does not return a value */
 108 #define INT_MOD_EXPR(reference,arch,code) \
 109     (((arch) == ARCH_NOCONVERT) \
 110         ? \
 111             (void)((reference) code) \
 112         : \
 113             (void)( \
 114                 (reference) = INT_GET((reference),arch) , \
 115                 ((reference) code), \
 116                 INT_SET(reference, arch, reference) \
 117             ) \
 118     )
 119
 120 /* does not return a value */
 121 #define INT_MOD(reference,arch,delta) \
 122     (void)( \
 123         INT_MOD_EXPR(reference,arch,+=(delta)) \
 124     )
 125
 126 /*
 127  * INT_COPY - copy a value between two locations with the
 128  *            _same architecture_ but _potentially different sizes_
 129  *
 130  *          if the types of the two parameters are equal or they are
 131  *              in native architecture, a simple copy is done
 132  *
 133  *          otherwise, architecture conversions are done
 134  *
 135  */
 136
 137 /* does not return a value */
 138 #define INT_COPY(dst,src,arch) \
 139     ( \
 140         ((sizeof(dst) == sizeof(src)) || ((arch) == ARCH_NOCONVERT)) \
 141             ? \
 142                 (void)((dst) = (src)) \
 143             : \
 144                 INT_SET(dst, arch, INT_GET(src, arch)) \
 145     )
 146
 147 /*
 148  * INT_XLATE - copy a value in either direction between two locations
 149  *             with different architectures
 150  *
 151  *                  dir < 0     - copy from memory to buffer (native to arch)
 152  *                  dir > 0     - copy from buffer to memory (arch to native)
 153  */
 154
 155 /* does not return a value */
 156 #define INT_XLATE(buf,mem,dir,arch) {\
 157     ASSERT(dir); \
 158     if (dir>0) { \
 159         (mem)=INT_GET(buf, arch); \
 160     } else { \
 161         INT_SET(buf, arch, mem); \
 162     } \
 163 }
 164
 165 /*
 166  * In directories inode numbers are stored as unaligned arrays of unsigned
 167  * 8bit integers on disk.
 168  *
 169  * For v1 directories or v2 directories that contain inode numbers that
 170  * do not fit into 32bit the array has eight members, but the first member
 171  * is always zero:
 172  *
 173  *  |unused|48-55|40-47|32-39|24-31|16-23| 8-15| 0- 7|
 174  *
 175  * For v2 directories that only contain entries with inode numbers that fit
 176  * into 32bits a four-member array is used:
 177  *
 178  *  |24-31|16-23| 8-15| 0- 7|
 179  */
 180
 181 #define XFS_GET_DIR_INO4(di) \
 182         (((u32)(di).i[0] << 24) | ((di).i[1] << 16) | ((di).i[2] << 8) | ((di).i[3]))
 183
 184 #define XFS_PUT_DIR_INO4(from, di) \
 185 do { \
 186         (di).i[0] = (((from) & 0xff000000ULL) >> 24); \
 187         (di).i[1] = (((from) & 0x00ff0000ULL) >> 16); \
 188         (di).i[2] = (((from) & 0x0000ff00ULL) >> 8); \
 189         (di).i[3] = ((from) & 0x000000ffULL); \
 190 } while (0)
 191
 192 #define XFS_DI_HI(di) \
 193         (((u32)(di).i[1] << 16) | ((di).i[2] << 8) | ((di).i[3]))
 194 #define XFS_DI_LO(di) \
 195         (((u32)(di).i[4] << 24) | ((di).i[5] << 16) | ((di).i[6] << 8) | ((di).i[7]))
 196
 197 #define XFS_GET_DIR_INO8(di)        \
 198         (((xfs_ino_t)XFS_DI_LO(di) & 0xffffffffULL) | \
 199          ((xfs_ino_t)XFS_DI_HI(di) << 32))
 200
 201 #define XFS_PUT_DIR_INO8(from, di) \
 202 do { \
 203         (di).i[0] = 0; \
 204         (di).i[1] = (((from) & 0x00ff000000000000ULL) >> 48); \
 205         (di).i[2] = (((from) & 0x0000ff0000000000ULL) >> 40); \
 206         (di).i[3] = (((from) & 0x000000ff00000000ULL) >> 32); \
 207         (di).i[4] = (((from) & 0x00000000ff000000ULL) >> 24); \
 208         (di).i[5] = (((from) & 0x0000000000ff0000ULL) >> 16); \
 209         (di).i[6] = (((from) & 0x000000000000ff00ULL) >> 8); \
 210         (di).i[7] = ((from) & 0x00000000000000ffULL); \
 211 } while (0)
 212
 213 #endif  /* __XFS_ARCH_H__ */