xref: /openbmc/linux/include/uapi/linux/swab.h (revision defbab27)
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 
__fswab16(__u16 val)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 
__fswab32(__u32 val)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 
__fswab64(__u64 val)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 
__fswahw32(__u32 val)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 
__fswahb32(__u32 val)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 
__swab(const unsigned long y)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  */
__swab16p(const __u16 * p)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  */
__swab32p(const __u32 * p)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  */
__swab64p(const __u64 * p)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  */
__swahw32p(const __u32 * p)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  */
__swahb32p(const __u32 * p)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  */
__swab16s(__u16 * p)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  */
__swab32s(__u32 * p)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  */
__swab64s(__u64 * p)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  */
__swahw32s(__u32 * p)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  */
__swahb32s(__u32 * p)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 */
306