29 Apr, 2008
1 commit
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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
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds