1#ifndef _ASM_GENERIC_UNALIGNED_H_
2#define _ASM_GENERIC_UNALIGNED_H_
3
4/*
5 * For the benefit of those who are trying to port Linux to another
6 * architecture, here are some C-language equivalents.
7 *
8 * This is based almost entirely upon Richard Henderson's
9 * asm-alpha/unaligned.h implementation.  Some comments were
10 * taken from David Mosberger's asm-ia64/unaligned.h header.
11 */
12
13#include <linux/types.h>
14
15/*
16 * The main single-value unaligned transfer routines.
17 */
18#define get_unaligned(ptr) \
19	__get_unaligned((ptr), sizeof(*(ptr)))
20#define put_unaligned(x,ptr) \
21	__put_unaligned((__u64)(x), (ptr), sizeof(*(ptr)))
22
23/*
24 * This function doesn't actually exist.  The idea is that when
25 * someone uses the macros below with an unsupported size (datatype),
26 * the linker will alert us to the problem via an unresolved reference
27 * error.
28 */
29extern void bad_unaligned_access_length(void) __attribute__((noreturn));
30
31struct __una_u64 { __u64 x __attribute__((packed)); };
32struct __una_u32 { __u32 x __attribute__((packed)); };
33struct __una_u16 { __u16 x __attribute__((packed)); };
34
35/*
36 * Elemental unaligned loads
37 */
38
39static inline __u64 __uldq(const __u64 *addr)
40{
41	const struct __una_u64 *ptr = (const struct __una_u64 *) addr;
42	return ptr->x;
43}
44
45static inline __u32 __uldl(const __u32 *addr)
46{
47	const struct __una_u32 *ptr = (const struct __una_u32 *) addr;
48	return ptr->x;
49}
50
51static inline __u16 __uldw(const __u16 *addr)
52{
53	const struct __una_u16 *ptr = (const struct __una_u16 *) addr;
54	return ptr->x;
55}
56
57/*
58 * Elemental unaligned stores
59 */
60
61static inline void __ustq(__u64 val, __u64 *addr)
62{
63	struct __una_u64 *ptr = (struct __una_u64 *) addr;
64	ptr->x = val;
65}
66
67static inline void __ustl(__u32 val, __u32 *addr)
68{
69	struct __una_u32 *ptr = (struct __una_u32 *) addr;
70	ptr->x = val;
71}
72
73static inline void __ustw(__u16 val, __u16 *addr)
74{
75	struct __una_u16 *ptr = (struct __una_u16 *) addr;
76	ptr->x = val;
77}
78
79#define __get_unaligned(ptr, size) ({		\
80	const void *__gu_p = ptr;		\
81	__u64 val;				\
82	switch (size) {				\
83	case 1:					\
84		val = *(const __u8 *)__gu_p;	\
85		break;				\
86	case 2:					\
87		val = __uldw(__gu_p);		\
88		break;				\
89	case 4:					\
90		val = __uldl(__gu_p);		\
91		break;				\
92	case 8:					\
93		val = __uldq(__gu_p);		\
94		break;				\
95	default:				\
96		bad_unaligned_access_length();	\
97	};					\
98	(__typeof__(*(ptr)))val;		\
99})
100
101#define __put_unaligned(val, ptr, size)		\
102do {						\
103	void *__gu_p = ptr;			\
104	switch (size) {				\
105	case 1:					\
106		*(__u8 *)__gu_p = val;		\
107	        break;				\
108	case 2:					\
109		__ustw(val, __gu_p);		\
110		break;				\
111	case 4:					\
112		__ustl(val, __gu_p);		\
113		break;				\
114	case 8:					\
115		__ustq(val, __gu_p);		\
116		break;				\
117	default:				\
118	    	bad_unaligned_access_length();	\
119	};					\
120} while(0)
121
122#endif /* _ASM_GENERIC_UNALIGNED_H */
123