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064106a91b
Create a linux/unaligned directory similar in spirit to the linux/byteorder
folder to hold generic implementations collected from various arches.
Currently there are five implementations:
1) packed_struct.h: C-struct based, from asm-generic/unaligned.h
2) le_byteshift.h: Open coded byte-swapping, heavily based on asm-arm
3) be_byteshift.h: Open coded byte-swapping, heavily based on asm-arm
4) memmove.h: taken from multiple implementations in tree
5) access_ok.h: taken from x86 and others, unaligned access is ok.
All of the new implementations checks for sizes not equal to 1,2,4,8
and will fail to link.
API additions:
get_unaligned_{le16|le32|le64|be16|be32|be64}(p) which is meant to replace
code of the form:
le16_to_cpu(get_unaligned((__le16 *)p));
put_unaligned_{le16|le32|le64|be16|be32|be64}(val, pointer) which is meant to
replace code of the form:
put_unaligned(cpu_to_le16(val), (__le16 *)p);
The headers that arches should include from their asm/unaligned.h:
access_ok.h : Wrappers of the byteswapping functions in asm/byteorder
Choose a particular implementation for little-endian access:
le_byteshift.h
le_memmove.h (arch must be LE)
le_struct.h (arch must be LE)
Choose a particular implementation for big-endian access:
be_byteshift.h
be_memmove.h (arch must be BE)
be_struct.h (arch must be BE)
After including as needed from the above, include unaligned/generic.h and
define your arch's get/put_unaligned as (for LE):
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
46 lines
829 B
C
46 lines
829 B
C
#ifndef _LINUX_UNALIGNED_MEMMOVE_H
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#define _LINUX_UNALIGNED_MEMMOVE_H
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#include <linux/kernel.h>
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#include <linux/string.h>
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/* Use memmove here, so gcc does not insert a __builtin_memcpy. */
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static inline u16 __get_unaligned_memmove16(const void *p)
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{
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u16 tmp;
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memmove(&tmp, p, 2);
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return tmp;
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}
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static inline u32 __get_unaligned_memmove32(const void *p)
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{
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u32 tmp;
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memmove(&tmp, p, 4);
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return tmp;
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}
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static inline u64 __get_unaligned_memmove64(const void *p)
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{
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u64 tmp;
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memmove(&tmp, p, 8);
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return tmp;
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}
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static inline void __put_unaligned_memmove16(u16 val, void *p)
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{
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memmove(p, &val, 2);
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}
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static inline void __put_unaligned_memmove32(u32 val, void *p)
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{
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memmove(p, &val, 4);
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}
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static inline void __put_unaligned_memmove64(u64 val, void *p)
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{
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memmove(p, &val, 8);
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}
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#endif /* _LINUX_UNALIGNED_MEMMOVE_H */
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