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/le_byteshift.h | 70 ++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 include/linux/unaligned/le_byteshift.h (limited to 'include/linux/unaligned/le_byteshift.h') diff --git a/include/linux/unaligned/le_byteshift.h b/include/linux/unaligned/le_byteshift.h new file mode 100644 index 000000000000..59777e951baf --- /dev/null +++ b/include/linux/unaligned/le_byteshift.h @@ -0,0 +1,70 @@ +#ifndef _LINUX_UNALIGNED_LE_BYTESHIFT_H +#define _LINUX_UNALIGNED_LE_BYTESHIFT_H + +#include + +static inline u16 __get_unaligned_le16(const u8 *p) +{ + return p[0] | p[1] << 8; +} + +static inline u32 __get_unaligned_le32(const u8 *p) +{ + return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24; +} + +static inline u64 __get_unaligned_le64(const u8 *p) +{ + return (u64)__get_unaligned_le32(p + 4) << 32 | + __get_unaligned_le32(p); +} + +static inline void __put_unaligned_le16(u16 val, u8 *p) +{ + *p++ = val; + *p++ = val >> 8; +} + +static inline void __put_unaligned_le32(u32 val, u8 *p) +{ + __put_unaligned_le16(val >> 16, p + 2); + __put_unaligned_le16(val, p); +} + +static inline void __put_unaligned_le64(u64 val, u8 *p) +{ + __put_unaligned_le32(val >> 32, p + 4); + __put_unaligned_le32(val, p); +} + +static inline u16 get_unaligned_le16(const void *p) +{ + return __get_unaligned_le16((const u8 *)p); +} + +static inline u32 get_unaligned_le32(const void *p) +{ + return __get_unaligned_le32((const u8 *)p); +} + +static inline u64 get_unaligned_le64(const void *p) +{ + return __get_unaligned_le64((const u8 *)p); +} + +static inline void put_unaligned_le16(u16 val, void *p) +{ + __put_unaligned_le16(val, p); +} + +static inline void put_unaligned_le32(u32 val, void *p) +{ + __put_unaligned_le32(val, p); +} + +static inline void put_unaligned_le64(u64 val, void *p) +{ + __put_unaligned_le64(val, p); +} + +#endif /* _LINUX_UNALIGNED_LE_BYTESHIFT_H */ -- cgit v1.2.1