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authorHarvey Harrison <harvey.harrison@gmail.com>2008-04-29 01:03:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:27 -0700
commit064106a91be5e76cb42c1ddf5d3871e3a1bd2a23 (patch)
tree7bb3931857c933343abf9a55d663e8a9b8af13ae /include/linux/unaligned/le_byteshift.h
parentdddfbaf8f86894415abb8256b55da68dab966ebe (diff)
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/le_byteshift.h')
-rw-r--r--include/linux/unaligned/le_byteshift.h70
1 files changed, 70 insertions, 0 deletions
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 <linux/kernel.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((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 */