linux/include/asm-generic/unaligned.h
Al Viro d37c6e1b67 saner typechecking in generic unaligned.h
Verify that types would match for assignment (under sizeof, so we are safe from
side effects or any code actually getting generated), then explicitly cast
everywhere to the fixed-sized types.  Kills a bunch of bogus warnings about
constants being truncated (gcc, sparse), finds a pile of endianness problems
hidden by old noise (sparse).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 11:01:07 -07:00

124 lines
2.8 KiB
C

#ifndef _ASM_GENERIC_UNALIGNED_H_
#define _ASM_GENERIC_UNALIGNED_H_
/*
* For the benefit of those who are trying to port Linux to another
* architecture, here are some C-language equivalents.
*
* This is based almost entirely upon Richard Henderson's
* asm-alpha/unaligned.h implementation. Some comments were
* taken from David Mosberger's asm-ia64/unaligned.h header.
*/
#include <linux/types.h>
/*
* The main single-value unaligned transfer routines.
*/
#define get_unaligned(ptr) \
__get_unaligned((ptr), sizeof(*(ptr)))
#define put_unaligned(x,ptr) \
((void)sizeof(*(ptr)=(x)),\
__put_unaligned((__force __u64)(x), (ptr), sizeof(*(ptr))))
/*
* This function doesn't actually exist. The idea is that when
* someone uses the macros below with an unsupported size (datatype),
* the linker will alert us to the problem via an unresolved reference
* error.
*/
extern void bad_unaligned_access_length(void) __attribute__((noreturn));
struct __una_u64 { __u64 x __attribute__((packed)); };
struct __una_u32 { __u32 x __attribute__((packed)); };
struct __una_u16 { __u16 x __attribute__((packed)); };
/*
* Elemental unaligned loads
*/
static inline __u64 __uldq(const __u64 *addr)
{
const struct __una_u64 *ptr = (const struct __una_u64 *) addr;
return ptr->x;
}
static inline __u32 __uldl(const __u32 *addr)
{
const struct __una_u32 *ptr = (const struct __una_u32 *) addr;
return ptr->x;
}
static inline __u16 __uldw(const __u16 *addr)
{
const struct __una_u16 *ptr = (const struct __una_u16 *) addr;
return ptr->x;
}
/*
* Elemental unaligned stores
*/
static inline void __ustq(__u64 val, __u64 *addr)
{
struct __una_u64 *ptr = (struct __una_u64 *) addr;
ptr->x = val;
}
static inline void __ustl(__u32 val, __u32 *addr)
{
struct __una_u32 *ptr = (struct __una_u32 *) addr;
ptr->x = val;
}
static inline void __ustw(__u16 val, __u16 *addr)
{
struct __una_u16 *ptr = (struct __una_u16 *) addr;
ptr->x = val;
}
#define __get_unaligned(ptr, size) ({ \
const void *__gu_p = ptr; \
__u64 val; \
switch (size) { \
case 1: \
val = *(const __u8 *)__gu_p; \
break; \
case 2: \
val = __uldw(__gu_p); \
break; \
case 4: \
val = __uldl(__gu_p); \
break; \
case 8: \
val = __uldq(__gu_p); \
break; \
default: \
bad_unaligned_access_length(); \
}; \
(__force __typeof__(*(ptr)))val; \
})
#define __put_unaligned(val, ptr, size) \
({ \
void *__gu_p = ptr; \
switch (size) { \
case 1: \
*(__u8 *)__gu_p = (__force __u8)val; \
break; \
case 2: \
__ustw((__force __u16)val, __gu_p); \
break; \
case 4: \
__ustl((__force __u32)val, __gu_p); \
break; \
case 8: \
__ustq(val, __gu_p); \
break; \
default: \
bad_unaligned_access_length(); \
}; \
(void)0; \
})
#endif /* _ASM_GENERIC_UNALIGNED_H */