mirror of https://gitee.com/openkylin/linux.git
123 lines
2.7 KiB
C
123 lines
2.7 KiB
C
#ifndef _ASM_GENERIC_UNALIGNED_H_
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#define _ASM_GENERIC_UNALIGNED_H_
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/*
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* For the benefit of those who are trying to port Linux to another
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* architecture, here are some C-language equivalents.
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*
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* This is based almost entirely upon Richard Henderson's
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* asm-alpha/unaligned.h implementation. Some comments were
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* taken from David Mosberger's asm-ia64/unaligned.h header.
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*/
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#include <linux/types.h>
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/*
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* The main single-value unaligned transfer routines.
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*/
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#define get_unaligned(ptr) \
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__get_unaligned((ptr), sizeof(*(ptr)))
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#define put_unaligned(x,ptr) \
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__put_unaligned((__u64)(x), (ptr), sizeof(*(ptr)))
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/*
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* This function doesn't actually exist. The idea is that when
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* someone uses the macros below with an unsupported size (datatype),
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* the linker will alert us to the problem via an unresolved reference
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* error.
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*/
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extern void bad_unaligned_access_length(void) __attribute__((noreturn));
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struct __una_u64 { __u64 x __attribute__((packed)); };
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struct __una_u32 { __u32 x __attribute__((packed)); };
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struct __una_u16 { __u16 x __attribute__((packed)); };
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/*
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* Elemental unaligned loads
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*/
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static inline __u64 __uldq(const __u64 *addr)
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{
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const struct __una_u64 *ptr = (const struct __una_u64 *) addr;
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return ptr->x;
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}
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static inline __u32 __uldl(const __u32 *addr)
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{
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const struct __una_u32 *ptr = (const struct __una_u32 *) addr;
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return ptr->x;
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}
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static inline __u16 __uldw(const __u16 *addr)
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{
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const struct __una_u16 *ptr = (const struct __una_u16 *) addr;
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return ptr->x;
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}
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/*
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* Elemental unaligned stores
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*/
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static inline void __ustq(__u64 val, __u64 *addr)
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{
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struct __una_u64 *ptr = (struct __una_u64 *) addr;
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ptr->x = val;
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}
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static inline void __ustl(__u32 val, __u32 *addr)
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{
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struct __una_u32 *ptr = (struct __una_u32 *) addr;
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ptr->x = val;
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}
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static inline void __ustw(__u16 val, __u16 *addr)
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{
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struct __una_u16 *ptr = (struct __una_u16 *) addr;
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ptr->x = val;
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}
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#define __get_unaligned(ptr, size) ({ \
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const void *__gu_p = ptr; \
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__typeof__(*(ptr)) val; \
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switch (size) { \
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case 1: \
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val = *(const __u8 *)__gu_p; \
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break; \
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case 2: \
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val = __uldw(__gu_p); \
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break; \
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case 4: \
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val = __uldl(__gu_p); \
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break; \
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case 8: \
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val = __uldq(__gu_p); \
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break; \
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default: \
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bad_unaligned_access_length(); \
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}; \
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val; \
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})
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#define __put_unaligned(val, ptr, size) \
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do { \
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void *__gu_p = ptr; \
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switch (size) { \
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case 1: \
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*(__u8 *)__gu_p = val; \
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break; \
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case 2: \
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__ustw(val, __gu_p); \
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break; \
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case 4: \
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__ustl(val, __gu_p); \
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break; \
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case 8: \
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__ustq(val, __gu_p); \
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break; \
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default: \
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bad_unaligned_access_length(); \
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}; \
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} while(0)
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#endif /* _ASM_GENERIC_UNALIGNED_H */
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