From: Arnd Bergmann Date: Fri, 7 May 2021 22:07:51 +0000 (+0200) Subject: asm-generic: unaligned: remove byteshift helpers X-Git-Tag: microblaze-v5.15~106^2~7 X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=commitdiff_plain;h=0652035a57945e14e611dafae2ec5b46a05bc1d1 asm-generic: unaligned: remove byteshift helpers In theory, compilers should be able to work this out themselves so we can use a simpler version based on the swab() helpers. I have verified that this works on all supported compiler versions (gcc-4.9 and up, clang-10 and up). Looking at the object code produced by gcc-11, I found that the impact is mostly a change in inlining decisions that lead to slightly larger code. In other cases, this version produces explicit byte swaps in place of separate byte access, or comparing against pre-swapped constants. While the source code is clearly simpler, I have not seen an indication of the new version actually producing better code on Arm, so maybe we want to skip this after all. From what I can tell, gcc recognizes the byteswap pattern in the byteshift.h header and can turn it into explicit instructions, but it does not turn a __builtin_bswap32() back into individual bytes when that would result in better output, e.g. when storing a byte-reversed constant. Suggested-by: Linus Torvalds Signed-off-by: Arnd Bergmann --- diff --git a/arch/arm/include/asm/unaligned.h b/arch/arm/include/asm/unaligned.h index ab905ffcf193..3c5248fb4cdc 100644 --- a/arch/arm/include/asm/unaligned.h +++ b/arch/arm/include/asm/unaligned.h @@ -10,13 +10,11 @@ #if defined(__LITTLE_ENDIAN) # include -# include # include # define get_unaligned __get_unaligned_le # define put_unaligned __put_unaligned_le #elif defined(__BIG_ENDIAN) # include -# include # include # define get_unaligned __get_unaligned_be # define put_unaligned __put_unaligned_be diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h index 374c940e9be1..d79df721ae60 100644 --- a/include/asm-generic/unaligned.h +++ b/include/asm-generic/unaligned.h @@ -16,7 +16,6 @@ #if defined(__LITTLE_ENDIAN) # ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS # include -# include # endif # include # define get_unaligned __get_unaligned_le @@ -24,7 +23,6 @@ #elif defined(__BIG_ENDIAN) # ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS # include -# include # endif # include # define get_unaligned __get_unaligned_be diff --git a/include/linux/unaligned/be_byteshift.h b/include/linux/unaligned/be_byteshift.h deleted file mode 100644 index c43ff5918c8a..000000000000 --- a/include/linux/unaligned/be_byteshift.h +++ /dev/null @@ -1,71 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _LINUX_UNALIGNED_BE_BYTESHIFT_H -#define _LINUX_UNALIGNED_BE_BYTESHIFT_H - -#include - -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(p); -} - -static inline u32 get_unaligned_be32(const void *p) -{ - return __get_unaligned_be32(p); -} - -static inline u64 get_unaligned_be64(const void *p) -{ - return __get_unaligned_be64(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 */ diff --git a/include/linux/unaligned/be_struct.h b/include/linux/unaligned/be_struct.h index 15ea503a13fc..76d9fe297c33 100644 --- a/include/linux/unaligned/be_struct.h +++ b/include/linux/unaligned/be_struct.h @@ -34,4 +34,34 @@ static inline void put_unaligned_be64(u64 val, void *p) __put_unaligned_cpu64(val, p); } +static inline u16 get_unaligned_le16(const void *p) +{ + return swab16(__get_unaligned_cpu16((const u8 *)p)); +} + +static inline u32 get_unaligned_le32(const void *p) +{ + return swab32(__get_unaligned_cpu32((const u8 *)p)); +} + +static inline u64 get_unaligned_le64(const void *p) +{ + return swab64(__get_unaligned_cpu64((const u8 *)p)); +} + +static inline void put_unaligned_le16(u16 val, void *p) +{ + __put_unaligned_cpu16(swab16(val), p); +} + +static inline void put_unaligned_le32(u32 val, void *p) +{ + __put_unaligned_cpu32(swab32(val), p); +} + +static inline void put_unaligned_le64(u64 val, void *p) +{ + __put_unaligned_cpu64(swab64(val), p); +} + #endif /* _LINUX_UNALIGNED_BE_STRUCT_H */ diff --git a/include/linux/unaligned/le_byteshift.h b/include/linux/unaligned/le_byteshift.h deleted file mode 100644 index 2248dcb0df76..000000000000 --- a/include/linux/unaligned/le_byteshift.h +++ /dev/null @@ -1,71 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#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(p); -} - -static inline u32 get_unaligned_le32(const void *p) -{ - return __get_unaligned_le32(p); -} - -static inline u64 get_unaligned_le64(const void *p) -{ - return __get_unaligned_le64(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 */ diff --git a/include/linux/unaligned/le_struct.h b/include/linux/unaligned/le_struct.h index 9977987883a6..22f90a4afaa5 100644 --- a/include/linux/unaligned/le_struct.h +++ b/include/linux/unaligned/le_struct.h @@ -34,4 +34,34 @@ static inline void put_unaligned_le64(u64 val, void *p) __put_unaligned_cpu64(val, p); } +static inline u16 get_unaligned_be16(const void *p) +{ + return swab16(__get_unaligned_cpu16((const u8 *)p)); +} + +static inline u32 get_unaligned_be32(const void *p) +{ + return swab32(__get_unaligned_cpu32((const u8 *)p)); +} + +static inline u64 get_unaligned_be64(const void *p) +{ + return swab64(__get_unaligned_cpu64((const u8 *)p)); +} + +static inline void put_unaligned_be16(u16 val, void *p) +{ + __put_unaligned_cpu16(swab16(val), p); +} + +static inline void put_unaligned_be32(u32 val, void *p) +{ + __put_unaligned_cpu32(swab32(val), p); +} + +static inline void put_unaligned_be64(u64 val, void *p) +{ + __put_unaligned_cpu64(swab64(val), p); +} + #endif /* _LINUX_UNALIGNED_LE_STRUCT_H */