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