There are two common cases in the kernel, one where unaligned access
is OK for an arch and one where the arch uses a packed-struct for
the native endianness and opencoded C byteshifting for the other
endianness. Consolidate these two implementations in asm-generic/unaligned.h
Arches that require no special handling of unaligned access can define
_UNALIGNED_ACCESS_OK in their asm/unaligned.h before including the generic
version.
Signed-off-by: Harvey Harrison <[email protected]>
---
Patches vs linux-next, 1-4 are suitable for mainline anytime as they are pure movement.
Patches 5-6 need some more input from other arch people (CCs added).
include/asm-generic/unaligned.h | 323 +++++++++++++++++++++++++++++++++++++++
1 files changed, 323 insertions(+), 0 deletions(-)
diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h
new file mode 100644
index 0000000..8dfca50
--- /dev/null
+++ b/include/asm-generic/unaligned.h
@@ -0,0 +1,323 @@
+#ifndef _ASM_GENERIC_UNALIGNED_H
+#define _ASM_GENERIC_UNALIGNED_H
+
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+#ifdef _UNALIGNED_ACCESS_OK
+
+static inline u16 get_unaligned_le16(const void *p)
+{
+ return le16_to_cpup(p);
+}
+
+static inline u32 get_unaligned_le32(const void *p)
+{
+ return le32_to_cpup(p);
+}
+
+static inline u64 get_unaligned_le64(const void *p)
+{
+ return le64_to_cpup(p);
+}
+
+static inline u16 get_unaligned_be16(const void *p)
+{
+ return be16_to_cpup(p);
+}
+
+static inline u32 get_unaligned_be32(const void *p)
+{
+ return be32_to_cpup(p);
+}
+
+static inline u64 get_unaligned_be64(const void *p)
+{
+ return be64_to_cpup(p);
+}
+
+static inline void put_unaligned_le16(u16 val, void *p)
+{
+ *(__le16 *)p = cpu_to_le16(val);
+}
+
+static inline void put_unaligned_le32(u32 val, void *p)
+{
+ *(__le32 *)p = cpu_to_le32(val);
+}
+
+static inline void put_unaligned_le64(u64 val, void *p)
+{
+ *(__le64 *)p = cpu_to_le64(val);
+}
+
+static inline void put_unaligned_be16(u16 val, void *p)
+{
+ *(__be16 *)p = cpu_to_be16(val);
+}
+
+static inline void put_unaligned_be32(u32 val, void *p)
+{
+ *(__be32 *)p = cpu_to_be32(val);
+}
+
+static inline void put_unaligned_be64(u64 val, void *p)
+{
+ *(__be64 *)p = cpu_to_be64(val);
+}
+
+#else /* _UNALIGNED_ACCESS_OK */
+
+struct __una_u16 { u16 x __attribute__((packed)); };
+struct __una_u32 { u32 x __attribute__((packed)); };
+struct __una_u64 { u64 x __attribute__((packed)); };
+
+static inline u16 __get_le16_noalign(const u8 *p)
+{
+ return p[0] | p[1] << 8;
+}
+
+static inline u32 __get_le32_noalign(const u8 *p)
+{
+ return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
+}
+
+static inline u64 __get_le64_noalign(const u8 *p)
+{
+ return ((u64)__get_le32_noalign(p + 4) << 32) | __get_le32_noalign(p);
+}
+
+static inline u16 __get_be16_noalign(const u8 *p)
+{
+ return p[0] << 8 | p[1];
+}
+
+static inline u32 __get_be32_noalign(const u8 *p)
+{
+ return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+}
+
+static inline u64 __get_be64_noalign(const u8 *p)
+{
+ return ((u64)__get_be32_noalign(p) << 32) | __get_be32_noalign(p + 4);
+}
+
+static inline u16 get_unaligned_le16(const void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ return ((const struct __una_u16 *)p)->x;
+#else
+ return __get_le16_noalign(p);
+#endif
+}
+
+static inline u32 get_unaligned_le32(const void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ return ((const struct __una_u32 *)p)->x;
+#else
+ return __get_le32_noalign(p);
+#endif
+}
+
+static inline u16 get_unaligned_le64(const void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ return ((const struct __una_u64 *)p)->x;
+#else
+ return __get_le64_noalign(p);
+#endif
+}
+
+static inline u16 get_unaligned_be16(const void *p)
+{
+#ifdef __BIG_ENDIAN
+ return ((const struct __una_u16 *)p)->x;
+#else
+ return __get_be16_noalign(p);
+#endif
+}
+
+static inline u32 get_unaligned_be32(const void *p)
+{
+#ifdef __BIG_ENDIAN
+ return ((const struct __una_u32 *)p)->x;
+#else
+ return __get_be32_noalign(p);
+#endif
+}
+
+static inline u16 get_unaligned_be64(const void *p)
+{
+#ifdef __BIG_ENDIAN
+ return ((const struct __una_u64 *)p)->x;
+#else
+ return __get_be64_noalign(p);
+#endif
+}
+
+static inline void __put_le16_noalign(u8 *p, u16 val)
+{
+ *p++ = val;
+ *p++ = val >> 8;
+}
+
+static inline void __put_le32_noalign(u8 *p, u32 val)
+{
+ __put_le16_noalign(p + 2, val >> 16);
+ __put_le16_noalign(p, val);
+}
+
+static inline void __put_le64_noalign(u8 *p, u64 val)
+{
+ __put_le32_noalign(p + 4, val >> 32);
+ __put_le32_noalign(p, val);
+}
+
+static inline void __put_be16_noalign(u8 *p, u16 val)
+{
+ *p++ = val >> 8;
+ *p++ = val;
+}
+
+static inline void __put_be32_noalign(u8 *p, u32 val)
+{
+ __put_be16_noalign(p, val >> 16);
+ __put_be16_noalign(p + 2, val);
+}
+
+static inline void __put_be64_noalign(u8 *p, u64 val)
+{
+ __put_be32_noalign(p, val >> 32);
+ __put_be32_noalign(p + 4, val);
+}
+
+static inline void put_unaligned_le16(u16 val, void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ ((struct __una_u16 *)p)->x = val;
+#else
+ __put_le16_noalign(p, val);
+#endif
+}
+
+static inline void put_unaligned_le32(u32 val, void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ ((struct __una_u32 *)p)->x = val;
+#else
+ __put_le32_noalign(p, val);
+#endif
+}
+
+static inline void put_unaligned_le64(u64 val, void *p)
+{
+#ifdef __LITTLE_ENDIAN
+ ((struct __una_u64 *)p)->x = val;
+#else
+ __put_le64_noalign(p, val);
+#endif
+}
+
+static inline void put_unaligned_be16(u16 val, void *p)
+{
+#ifdef __BIG_ENDIAN
+ ((struct __una_u16 *)p)->x = val;
+#else
+ __put_be16_noalign(p, val);
+#endif
+}
+
+static inline void put_unaligned_be32(u32 val, void *p)
+{
+#ifdef __BIG_ENDIAN
+ ((struct __una_u32 *)p)->x = val;
+#else
+ __put_be32_noalign(p, val);
+#endif
+}
+
+static inline void put_unaligned_be64(u64 val, void *p)
+{
+#ifdef __BIG_ENDIAN
+ ((struct __una_u64 *)p)->x = val;
+#else
+ __put_be64_noalign(p, val);
+#endif
+}
+
+#endif /* _UNALIGNED_ACCESS_OK */
+
+/*
+ * Cause a link-time error if we try an unaligned access other than
+ * 1,2,4 or 8 bytes long
+ */
+extern void __bad_unaligned_access_size(void);
+
+#define __get_unaligned_le(ptr) ((__force typeof(*(ptr)))({ \
+ __builtin_choose_expr(sizeof(*(ptr)) == 1, *(ptr), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 2, get_unaligned_le16((ptr)), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 4, get_unaligned_le32((ptr)), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 8, get_unaligned_le64((ptr)), \
+ __bad_unaligned_access_size())))); \
+ }))
+
+#define __get_unaligned_be(ptr) ((__force typeof(*(ptr)))({ \
+ __builtin_choose_expr(sizeof(*(ptr)) == 1, *(ptr), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 2, get_unaligned_be16((ptr)), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 4, get_unaligned_be32((ptr)), \
+ __builtin_choose_expr(sizeof(*(ptr)) == 8, get_unaligned_be64((ptr)), \
+ __bad_unaligned_access_size())))); \
+ }))
+
+#define __put_unaligned_le(val, ptr) ({ \
+ void *__gu_p = (ptr); \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ *(u8 *)__gu_p = (__force u8)(val); \
+ break; \
+ case 2: \
+ put_unaligned_le16((__force u16)(val), __gu_p); \
+ break; \
+ case 4: \
+ put_unaligned_le32((__force u32)(val), __gu_p); \
+ break; \
+ case 8: \
+ put_unaligned_le64((__force u64)(val), __gu_p); \
+ break; \
+ default: \
+ __bad_unaligned_access_size(); \
+ break; \
+ } \
+ (void)0; })
+
+#define __put_unaligned_be(val, ptr) ({ \
+ void *__gu_p = (ptr); \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ *(u8 *)__gu_p = (__force u8)(val); \
+ break; \
+ case 2: \
+ put_unaligned_be16((__force u16)(val), __gu_p); \
+ break; \
+ case 4: \
+ put_unaligned_be32((__force u32)(val), __gu_p); \
+ break; \
+ case 8: \
+ put_unaligned_be64((__force u64)(val), __gu_p); \
+ break; \
+ default: \
+ __bad_unaligned_access_size(); \
+ break; \
+ } \
+ (void)0; })
+
+#ifdef __LITTLE_ENDIAN
+# define get_unaligned __get_unaligned_le
+# define put_unaligned __put_unaligned_le
+#else
+# define get_unaligned __get_unaligned_be
+# define put_unaligned __put_unaligned_be
+#endif
+
+#endif /* _ASM_GENERIC_UNALIGNED_H */
--
1.6.0.4.994.g16bd3e