diff options
author | Harvey Harrison <harvey.harrison@gmail.com> | 2008-04-29 12:03:27 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 19:06:27 +0400 |
commit | 064106a91be5e76cb42c1ddf5d3871e3a1bd2a23 (patch) | |
tree | 7bb3931857c933343abf9a55d663e8a9b8af13ae /include/linux/unaligned/be_byteshift.h | |
parent | dddfbaf8f86894415abb8256b55da68dab966ebe (diff) | |
download | linux-064106a91be5e76cb42c1ddf5d3871e3a1bd2a23.tar.xz |
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 <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>
Diffstat (limited to 'include/linux/unaligned/be_byteshift.h')
-rw-r--r-- | include/linux/unaligned/be_byteshift.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/include/linux/unaligned/be_byteshift.h b/include/linux/unaligned/be_byteshift.h new file mode 100644 index 000000000000..46dd12c5709e --- /dev/null +++ b/include/linux/unaligned/be_byteshift.h @@ -0,0 +1,70 @@ +#ifndef _LINUX_UNALIGNED_BE_BYTESHIFT_H +#define _LINUX_UNALIGNED_BE_BYTESHIFT_H + +#include <linux/kernel.h> + +static inline u16 __get_unaligned_be16(const u8 *p) +{ + return p[0] << 8 | p[1]; +} + +static inline u32 __get_unaligned_be32(const u8 *p) +{ + return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3]; +} + +static inline u64 __get_unaligned_be64(const u8 *p) +{ + return (u64)__get_unaligned_be32(p) << 32 | + __get_unaligned_be32(p + 4); +} + +static inline void __put_unaligned_be16(u16 val, u8 *p) +{ + *p++ = val >> 8; + *p++ = val; +} + +static inline void __put_unaligned_be32(u32 val, u8 *p) +{ + __put_unaligned_be16(val >> 16, p); + __put_unaligned_be16(val, p + 2); +} + +static inline void __put_unaligned_be64(u64 val, u8 *p) +{ + __put_unaligned_be32(val >> 32, p); + __put_unaligned_be32(val, p + 4); +} + +static inline u16 get_unaligned_be16(const void *p) +{ + return __get_unaligned_be16((const u8 *)p); +} + +static inline u32 get_unaligned_be32(const void *p) +{ + return __get_unaligned_be32((const u8 *)p); +} + +static inline u64 get_unaligned_be64(const void *p) +{ + return __get_unaligned_be64((const u8 *)p); +} + +static inline void put_unaligned_be16(u16 val, void *p) +{ + __put_unaligned_be16(val, p); +} + +static inline void put_unaligned_be32(u32 val, void *p) +{ + __put_unaligned_be32(val, p); +} + +static inline void put_unaligned_be64(u64 val, void *p) +{ + __put_unaligned_be64(val, p); +} + +#endif /* _LINUX_UNALIGNED_BE_BYTESHIFT_H */ |