Commit 803f4e1e authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

asm-generic: simplify asm/unaligned.h 



The get_unaligned()/put_unaligned() implementations are much more complex
than necessary, now that all architectures use the same code.

Move everything into one file and use a much more compact way to express
the same logic.

I've compared the binary output using gcc-11 across defconfig builds for
all architectures and found this patch to make no difference, except for
a single function on powerpc that needs two additional register moves
because of random differences in register allocation.

There are a handful of callers of the low-level __get_unaligned_cpu32,
so leave that in place for the time being even though the common code
no longer uses it.

This adds a warning for any caller of get_unaligned()/put_unaligned()
that passes in a single-byte pointer, but I've sent patches for all
instances that show up in x86 and randconfig builds. It would be nice
to change the arguments of the endian-specific accessors to take the
matching __be16/__be32/__be64/__le16/__le32/__le64 arguments instead of
a void pointer, but that requires more changes to the rest of the kernel.

This new version does allow aggregate types into get_unaligned(), which
was not the original goal but might come in handy.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent d40d8179

include/asm-generic/unaligned.h

+117 −13
Original line number Diff line number Diff line
@@ -6,20 +6,124 @@ 
 * This is the most generic implementation of unaligned accesses

 * and should work almost anywhere.

 */

#include <linux/unaligned/packed_struct.h>

#include <asm/byteorder.h>



#if defined(__LITTLE_ENDIAN)

# include <linux/unaligned/le_struct.h>

# include <linux/unaligned/generic.h>

# define get_unaligned	__get_unaligned_le

# define put_unaligned	__put_unaligned_le

#elif defined(__BIG_ENDIAN)

# include <linux/unaligned/be_struct.h>

# include <linux/unaligned/generic.h>

# define get_unaligned	__get_unaligned_be

# define put_unaligned	__put_unaligned_be

#else

# error need to define endianess

#endif

#define __get_unaligned_t(type, ptr) ({						\

	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\

	__pptr->x;								\

})



#define __put_unaligned_t(type, val, ptr) do {					\

	struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);		\

	__pptr->x = (val);							\

} while (0)



#define get_unaligned(ptr)	__get_unaligned_t(typeof(*(ptr)), (ptr))

#define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr))



static inline u16 get_unaligned_le16(const void *p)

{

	return le16_to_cpu(__get_unaligned_t(__le16, p));

}



static inline u32 get_unaligned_le32(const void *p)

{

	return le32_to_cpu(__get_unaligned_t(__le32, p));

}



static inline u64 get_unaligned_le64(const void *p)

{

	return le64_to_cpu(__get_unaligned_t(__le64, p));

}



static inline void put_unaligned_le16(u16 val, void *p)

{

	__put_unaligned_t(__le16, cpu_to_le16(val), p);

}



static inline void put_unaligned_le32(u32 val, void *p)

{

	__put_unaligned_t(__le32, cpu_to_le32(val), p);

}



static inline void put_unaligned_le64(u64 val, void *p)

{

	__put_unaligned_t(__le64, cpu_to_le64(val), p);

}



static inline u16 get_unaligned_be16(const void *p)

{

	return be16_to_cpu(__get_unaligned_t(__be16, p));

}



static inline u32 get_unaligned_be32(const void *p)

{

	return be32_to_cpu(__get_unaligned_t(__be32, p));

}



static inline u64 get_unaligned_be64(const void *p)

{

	return be64_to_cpu(__get_unaligned_t(__be64, p));

}



static inline void put_unaligned_be16(u16 val, void *p)

{

	__put_unaligned_t(__be16, cpu_to_be16(val), p);

}



static inline void put_unaligned_be32(u32 val, void *p)

{

	__put_unaligned_t(__be32, cpu_to_be32(val), p);

}



static inline void put_unaligned_be64(u64 val, void *p)

{

	__put_unaligned_t(__be64, cpu_to_be64(val), p);

}



static inline u32 __get_unaligned_be24(const u8 *p)

{

	return p[0] << 16 | p[1] << 8 | p[2];

}



static inline u32 get_unaligned_be24(const void *p)

{

	return __get_unaligned_be24(p);

}



static inline u32 __get_unaligned_le24(const u8 *p)

{

	return p[0] | p[1] << 8 | p[2] << 16;

}



static inline u32 get_unaligned_le24(const void *p)

{

	return __get_unaligned_le24(p);

}



static inline void __put_unaligned_be24(const u32 val, u8 *p)

{

	*p++ = val >> 16;

	*p++ = val >> 8;

	*p++ = val;

}



static inline void put_unaligned_be24(const u32 val, void *p)

{

	__put_unaligned_be24(val, p);

}



static inline void __put_unaligned_le24(const u32 val, u8 *p)

{

	*p++ = val;

	*p++ = val >> 8;

	*p++ = val >> 16;

}



static inline void put_unaligned_le24(const u32 val, void *p)

{

	__put_unaligned_le24(val, p);

}



#endif /* __ASM_GENERIC_UNALIGNED_H */

include/linux/unaligned/be_struct.h

deleted100644 → 0
+0 −67
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_UNALIGNED_BE_STRUCT_H

#define _LINUX_UNALIGNED_BE_STRUCT_H



#include <linux/unaligned/packed_struct.h>



static inline u16 get_unaligned_be16(const void *p)

{

	return __get_unaligned_cpu16((const u8 *)p);

}



static inline u32 get_unaligned_be32(const void *p)

{

	return __get_unaligned_cpu32((const u8 *)p);

}



static inline u64 get_unaligned_be64(const void *p)

{

	return __get_unaligned_cpu64((const u8 *)p);

}



static inline void put_unaligned_be16(u16 val, void *p)

{

	__put_unaligned_cpu16(val, p);

}



static inline void put_unaligned_be32(u32 val, void *p)

{

	__put_unaligned_cpu32(val, p);

}



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 */

include/linux/unaligned/generic.h

deleted100644 → 0
+0 −115
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_UNALIGNED_GENERIC_H

#define _LINUX_UNALIGNED_GENERIC_H



#include <linux/types.h>



/*

 * 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; })



static inline u32 __get_unaligned_be24(const u8 *p)

{

	return p[0] << 16 | p[1] << 8 | p[2];

}



static inline u32 get_unaligned_be24(const void *p)

{

	return __get_unaligned_be24(p);

}



static inline u32 __get_unaligned_le24(const u8 *p)

{

	return p[0] | p[1] << 8 | p[2] << 16;

}



static inline u32 get_unaligned_le24(const void *p)

{

	return __get_unaligned_le24(p);

}



static inline void __put_unaligned_be24(const u32 val, u8 *p)

{

	*p++ = val >> 16;

	*p++ = val >> 8;

	*p++ = val;

}



static inline void put_unaligned_be24(const u32 val, void *p)

{

	__put_unaligned_be24(val, p);

}



static inline void __put_unaligned_le24(const u32 val, u8 *p)

{

	*p++ = val;

	*p++ = val >> 8;

	*p++ = val >> 16;

}



static inline void put_unaligned_le24(const u32 val, void *p)

{

	__put_unaligned_le24(val, p);

}



#endif /* _LINUX_UNALIGNED_GENERIC_H */

include/linux/unaligned/le_struct.h

deleted100644 → 0
+0 −67
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_UNALIGNED_LE_STRUCT_H

#define _LINUX_UNALIGNED_LE_STRUCT_H



#include <linux/unaligned/packed_struct.h>



static inline u16 get_unaligned_le16(const void *p)

{

	return __get_unaligned_cpu16((const u8 *)p);

}



static inline u32 get_unaligned_le32(const void *p)

{

	return __get_unaligned_cpu32((const u8 *)p);

}



static inline u64 get_unaligned_le64(const void *p)

{

	return __get_unaligned_cpu64((const u8 *)p);

}



static inline void put_unaligned_le16(u16 val, void *p)

{

	__put_unaligned_cpu16(val, p);

}



static inline void put_unaligned_le32(u32 val, void *p)

{

	__put_unaligned_cpu32(val, p);

}



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 */