From 064106a91be5e76cb42c1ddf5d3871e3a1bd2a23 Mon Sep 17 00:00:00 2001 From: Harvey Harrison Date: Tue, 29 Apr 2008 01:03:27 -0700 Subject: kernel: add common infrastructure for unaligned access 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 --- include/linux/unaligned/memmove.h | 45 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 include/linux/unaligned/memmove.h (limited to 'include/linux/unaligned/memmove.h') diff --git a/include/linux/unaligned/memmove.h b/include/linux/unaligned/memmove.h new file mode 100644 index 000000000000..eeb5a779a4fd --- /dev/null +++ b/include/linux/unaligned/memmove.h @@ -0,0 +1,45 @@ +#ifndef _LINUX_UNALIGNED_MEMMOVE_H +#define _LINUX_UNALIGNED_MEMMOVE_H + +#include +#include + +/* Use memmove here, so gcc does not insert a __builtin_memcpy. */ + +static inline u16 __get_unaligned_memmove16(const void *p) +{ + u16 tmp; + memmove(&tmp, p, 2); + return tmp; +} + +static inline u32 __get_unaligned_memmove32(const void *p) +{ + u32 tmp; + memmove(&tmp, p, 4); + return tmp; +} + +static inline u64 __get_unaligned_memmove64(const void *p) +{ + u64 tmp; + memmove(&tmp, p, 8); + return tmp; +} + +static inline void __put_unaligned_memmove16(u16 val, void *p) +{ + memmove(p, &val, 2); +} + +static inline void __put_unaligned_memmove32(u32 val, void *p) +{ + memmove(p, &val, 4); +} + +static inline void __put_unaligned_memmove64(u64 val, void *p) +{ + memmove(p, &val, 8); +} + +#endif /* _LINUX_UNALIGNED_MEMMOVE_H */ -- cgit v1.2.3