include/uapi/linux/swab.h

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _UAPI_LINUX_SWAB_H
   3 #define _UAPI_LINUX_SWAB_H
   4
   5 #include <linux/types.h>
   6 #include <linux/stddef.h>
   7 #include <asm/bitsperlong.h>
   8 #include <asm/swab.h>
   9
  10 /*
  11  * casts are necessary for constants, because we never know how for sure
  12  * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
  13  */
  14 #define ___constant_swab16(x) ((__u16)(                         \
  15         (((__u16)(x) & (__u16)0x00ffU) << 8) |                  \
  16         (((__u16)(x) & (__u16)0xff00U) >> 8)))
  17
  18 #define ___constant_swab32(x) ((__u32)(                         \
  19         (((__u32)(x) & (__u32)0x000000ffUL) << 24) |            \
  20         (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) |            \
  21         (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) |            \
  22         (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
  23
  24 #define ___constant_swab64(x) ((__u64)(                         \
  25         (((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) |   \
  26         (((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) |   \
  27         (((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) |   \
  28         (((__u64)(x) & (__u64)0x00000000ff000000ULL) <<  8) |   \
  29         (((__u64)(x) & (__u64)0x000000ff00000000ULL) >>  8) |   \
  30         (((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) |   \
  31         (((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) |   \
  32         (((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56)))
  33
  34 #define ___constant_swahw32(x) ((__u32)(                        \
  35         (((__u32)(x) & (__u32)0x0000ffffUL) << 16) |            \
  36         (((__u32)(x) & (__u32)0xffff0000UL) >> 16)))
  37
  38 #define ___constant_swahb32(x) ((__u32)(                        \
  39         (((__u32)(x) & (__u32)0x00ff00ffUL) << 8) |             \
  40         (((__u32)(x) & (__u32)0xff00ff00UL) >> 8)))
  41
  42 /*
  43  * Implement the following as inlines, but define the interface using
  44  * macros to allow constant folding when possible:
  45  * ___swab16, ___swab32, ___swab64, ___swahw32, ___swahb32
  46  */
  47
  48 static inline __attribute_const__ __u16 __fswab16(__u16 val)
  49 {
  50 #if defined (__arch_swab16)
  51         return __arch_swab16(val);
  52 #else
  53         return ___constant_swab16(val);
  54 #endif
  55 }
  56
  57 static inline __attribute_const__ __u32 __fswab32(__u32 val)
  58 {
  59 #if defined(__arch_swab32)
  60         return __arch_swab32(val);
  61 #else
  62         return ___constant_swab32(val);
  63 #endif
  64 }
  65
  66 static inline __attribute_const__ __u64 __fswab64(__u64 val)
  67 {
  68 #if defined (__arch_swab64)
  69         return __arch_swab64(val);
  70 #elif defined(__SWAB_64_THRU_32__)
  71         __u32 h = val >> 32;
  72         __u32 l = val & ((1ULL << 32) - 1);
  73         return (((__u64)__fswab32(l)) << 32) | ((__u64)(__fswab32(h)));
  74 #else
  75         return ___constant_swab64(val);
  76 #endif
  77 }
  78
  79 static inline __attribute_const__ __u32 __fswahw32(__u32 val)
  80 {
  81 #ifdef __arch_swahw32
  82         return __arch_swahw32(val);
  83 #else
  84         return ___constant_swahw32(val);
  85 #endif
  86 }
  87
  88 static inline __attribute_const__ __u32 __fswahb32(__u32 val)
  89 {
  90 #ifdef __arch_swahb32
  91         return __arch_swahb32(val);
  92 #else
  93         return ___constant_swahb32(val);
  94 #endif
  95 }
  96
  97 /**
  98  * __swab16 - return a byteswapped 16-bit value
  99  * @x: value to byteswap
 100  */
 101 #ifdef __HAVE_BUILTIN_BSWAP16__
 102 #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
 103 #else
 104 #define __swab16(x)                             \
 105         (__u16)(__builtin_constant_p(x) ?       \
 106         ___constant_swab16(x) :                 \
 107         __fswab16(x))
 108 #endif
 109
 110 /**
 111  * __swab32 - return a byteswapped 32-bit value
 112  * @x: value to byteswap
 113  */
 114 #ifdef __HAVE_BUILTIN_BSWAP32__
 115 #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
 116 #else
 117 #define __swab32(x)                             \
 118         (__u32)(__builtin_constant_p(x) ?       \
 119         ___constant_swab32(x) :                 \
 120         __fswab32(x))
 121 #endif
 122
 123 /**
 124  * __swab64 - return a byteswapped 64-bit value
 125  * @x: value to byteswap
 126  */
 127 #ifdef __HAVE_BUILTIN_BSWAP64__
 128 #define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
 129 #else
 130 #define __swab64(x)                             \
 131         (__u64)(__builtin_constant_p(x) ?       \
 132         ___constant_swab64(x) :                 \
 133         __fswab64(x))
 134 #endif
 135
 136 static __always_inline unsigned long __swab(const unsigned long y)
 137 {
 138 #if __BITS_PER_LONG == 64
 139         return __swab64(y);
 140 #else /* __BITS_PER_LONG == 32 */
 141         return __swab32(y);
 142 #endif
 143 }
 144
 145 /**
 146  * __swahw32 - return a word-swapped 32-bit value
 147  * @x: value to wordswap
 148  *
 149  * __swahw32(0x12340000) is 0x00001234
 150  */
 151 #define __swahw32(x)                            \
 152         (__builtin_constant_p((__u32)(x)) ?     \
 153         ___constant_swahw32(x) :                \
 154         __fswahw32(x))
 155
 156 /**
 157  * __swahb32 - return a high and low byte-swapped 32-bit value
 158  * @x: value to byteswap
 159  *
 160  * __swahb32(0x12345678) is 0x34127856
 161  */
 162 #define __swahb32(x)                            \
 163         (__builtin_constant_p((__u32)(x)) ?     \
 164         ___constant_swahb32(x) :                \
 165         __fswahb32(x))
 166
 167 /**
 168  * __swab16p - return a byteswapped 16-bit value from a pointer
 169  * @p: pointer to a naturally-aligned 16-bit value
 170  */
 171 static __always_inline __u16 __swab16p(const __u16 *p)
 172 {
 173 #ifdef __arch_swab16p
 174         return __arch_swab16p(p);
 175 #else
 176         return __swab16(*p);
 177 #endif
 178 }
 179
 180 /**
 181  * __swab32p - return a byteswapped 32-bit value from a pointer
 182  * @p: pointer to a naturally-aligned 32-bit value
 183  */
 184 static __always_inline __u32 __swab32p(const __u32 *p)
 185 {
 186 #ifdef __arch_swab32p
 187         return __arch_swab32p(p);
 188 #else
 189         return __swab32(*p);
 190 #endif
 191 }
 192
 193 /**
 194  * __swab64p - return a byteswapped 64-bit value from a pointer
 195  * @p: pointer to a naturally-aligned 64-bit value
 196  */
 197 static __always_inline __u64 __swab64p(const __u64 *p)
 198 {
 199 #ifdef __arch_swab64p
 200         return __arch_swab64p(p);
 201 #else
 202         return __swab64(*p);
 203 #endif
 204 }
 205
 206 /**
 207  * __swahw32p - return a wordswapped 32-bit value from a pointer
 208  * @p: pointer to a naturally-aligned 32-bit value
 209  *
 210  * See __swahw32() for details of wordswapping.
 211  */
 212 static inline __u32 __swahw32p(const __u32 *p)
 213 {
 214 #ifdef __arch_swahw32p
 215         return __arch_swahw32p(p);
 216 #else
 217         return __swahw32(*p);
 218 #endif
 219 }
 220
 221 /**
 222  * __swahb32p - return a high and low byteswapped 32-bit value from a pointer
 223  * @p: pointer to a naturally-aligned 32-bit value
 224  *
 225  * See __swahb32() for details of high/low byteswapping.
 226  */
 227 static inline __u32 __swahb32p(const __u32 *p)
 228 {
 229 #ifdef __arch_swahb32p
 230         return __arch_swahb32p(p);
 231 #else
 232         return __swahb32(*p);
 233 #endif
 234 }
 235
 236 /**
 237  * __swab16s - byteswap a 16-bit value in-place
 238  * @p: pointer to a naturally-aligned 16-bit value
 239  */
 240 static inline void __swab16s(__u16 *p)
 241 {
 242 #ifdef __arch_swab16s
 243         __arch_swab16s(p);
 244 #else
 245         *p = __swab16p(p);
 246 #endif
 247 }
 248 /**
 249  * __swab32s - byteswap a 32-bit value in-place
 250  * @p: pointer to a naturally-aligned 32-bit value
 251  */
 252 static __always_inline void __swab32s(__u32 *p)
 253 {
 254 #ifdef __arch_swab32s
 255         __arch_swab32s(p);
 256 #else
 257         *p = __swab32p(p);
 258 #endif
 259 }
 260
 261 /**
 262  * __swab64s - byteswap a 64-bit value in-place
 263  * @p: pointer to a naturally-aligned 64-bit value
 264  */
 265 static __always_inline void __swab64s(__u64 *p)
 266 {
 267 #ifdef __arch_swab64s
 268         __arch_swab64s(p);
 269 #else
 270         *p = __swab64p(p);
 271 #endif
 272 }
 273
 274 /**
 275  * __swahw32s - wordswap a 32-bit value in-place
 276  * @p: pointer to a naturally-aligned 32-bit value
 277  *
 278  * See __swahw32() for details of wordswapping
 279  */
 280 static inline void __swahw32s(__u32 *p)
 281 {
 282 #ifdef __arch_swahw32s
 283         __arch_swahw32s(p);
 284 #else
 285         *p = __swahw32p(p);
 286 #endif
 287 }
 288
 289 /**
 290  * __swahb32s - high and low byteswap a 32-bit value in-place
 291  * @p: pointer to a naturally-aligned 32-bit value
 292  *
 293  * See __swahb32() for details of high and low byte swapping
 294  */
 295 static inline void __swahb32s(__u32 *p)
 296 {
 297 #ifdef __arch_swahb32s
 298         __arch_swahb32s(p);
 299 #else
 300         *p = __swahb32p(p);
 301 #endif
 302 }
 303
 304
 305 #endif /* _UAPI_LINUX_SWAB_H */