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authorArnd Bergmann <arnd@arndb.de>2021-05-08 01:07:51 +0300
committerArnd Bergmann <arnd@arndb.de>2021-05-10 18:50:47 +0300
commit0652035a57945e14e611dafae2ec5b46a05bc1d1 (patch)
tree0c34544a7755bc1ee0a822e86458d3ed9215533f /include/linux/unaligned
parentf12d3ff3f41cc92f67cfaf29697685e8834fe4a4 (diff)
downloadlinux-0652035a57945e14e611dafae2ec5b46a05bc1d1.tar.xz
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 <torvalds@linux-foundation.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/linux/unaligned')
-rw-r--r--include/linux/unaligned/be_byteshift.h71
-rw-r--r--include/linux/unaligned/be_struct.h30
-rw-r--r--include/linux/unaligned/le_byteshift.h71
-rw-r--r--include/linux/unaligned/le_struct.h30
4 files changed, 60 insertions, 142 deletions
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 <linux/types.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(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 <linux/types.h>
-
-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 */