linux-stable/include/uapi/linux/swab.h
Christian Borntraeger 467d12f5c7 include/uapi/linux/swab.h: fix userspace breakage, use __BITS_PER_LONG for swap
QEMU has a funny new build error message when I use the upstream kernel
headers:

      CC      block/file-posix.o
    In file included from /home/cborntra/REPOS/qemu/include/qemu/timer.h:4,
                     from /home/cborntra/REPOS/qemu/include/qemu/timed-average.h:29,
                     from /home/cborntra/REPOS/qemu/include/block/accounting.h:28,
                     from /home/cborntra/REPOS/qemu/include/block/block_int.h:27,
                     from /home/cborntra/REPOS/qemu/block/file-posix.c:30:
    /usr/include/linux/swab.h: In function `__swab':
    /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef]
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                  ^~~~~~
    /home/cborntra/REPOS/qemu/include/qemu/bitops.h:20:41: error: missing binary operator before token "("
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                         ^
    cc1: all warnings being treated as errors
    make: *** [/home/cborntra/REPOS/qemu/rules.mak:69: block/file-posix.o] Error 1
    rm tests/qemu-iotests/socket_scm_helper.o

This was triggered by commit d5767057c9 ("uapi: rename ext2_swab() to
swab() and share globally in swab.h").  That patch is doing

  #include <asm/bitsperlong.h>

but it uses BITS_PER_LONG.

The kernel file asm/bitsperlong.h provide only __BITS_PER_LONG.

Let us use the __ variant in swap.h

Link: http://lkml.kernel.org/r/20200213142147.17604-1-borntraeger@de.ibm.com
Fixes: d5767057c9 ("uapi: rename ext2_swab() to swab() and share globally in swab.h")
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Joe Perches <joe@perches.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-21 11:22:15 -08:00

305 lines
6.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_SWAB_H
#define _UAPI_LINUX_SWAB_H
#include <linux/types.h>
#include <linux/compiler.h>
#include <asm/bitsperlong.h>
#include <asm/swab.h>
/*
* casts are necessary for constants, because we never know how for sure
* how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
*/
#define ___constant_swab16(x) ((__u16)( \
(((__u16)(x) & (__u16)0x00ffU) << 8) | \
(((__u16)(x) & (__u16)0xff00U) >> 8)))
#define ___constant_swab32(x) ((__u32)( \
(((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
(((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \
(((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \
(((__u32)(x) & (__u32)0xff000000UL) >> 24)))
#define ___constant_swab64(x) ((__u64)( \
(((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \
(((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \
(((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \
(((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \
(((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \
(((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
(((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \
(((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56)))
#define ___constant_swahw32(x) ((__u32)( \
(((__u32)(x) & (__u32)0x0000ffffUL) << 16) | \
(((__u32)(x) & (__u32)0xffff0000UL) >> 16)))
#define ___constant_swahb32(x) ((__u32)( \
(((__u32)(x) & (__u32)0x00ff00ffUL) << 8) | \
(((__u32)(x) & (__u32)0xff00ff00UL) >> 8)))
/*
* Implement the following as inlines, but define the interface using
* macros to allow constant folding when possible:
* ___swab16, ___swab32, ___swab64, ___swahw32, ___swahb32
*/
static inline __attribute_const__ __u16 __fswab16(__u16 val)
{
#if defined (__arch_swab16)
return __arch_swab16(val);
#else
return ___constant_swab16(val);
#endif
}
static inline __attribute_const__ __u32 __fswab32(__u32 val)
{
#if defined(__arch_swab32)
return __arch_swab32(val);
#else
return ___constant_swab32(val);
#endif
}
static inline __attribute_const__ __u64 __fswab64(__u64 val)
{
#if defined (__arch_swab64)
return __arch_swab64(val);
#elif defined(__SWAB_64_THRU_32__)
__u32 h = val >> 32;
__u32 l = val & ((1ULL << 32) - 1);
return (((__u64)__fswab32(l)) << 32) | ((__u64)(__fswab32(h)));
#else
return ___constant_swab64(val);
#endif
}
static inline __attribute_const__ __u32 __fswahw32(__u32 val)
{
#ifdef __arch_swahw32
return __arch_swahw32(val);
#else
return ___constant_swahw32(val);
#endif
}
static inline __attribute_const__ __u32 __fswahb32(__u32 val)
{
#ifdef __arch_swahb32
return __arch_swahb32(val);
#else
return ___constant_swahb32(val);
#endif
}
/**
* __swab16 - return a byteswapped 16-bit value
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP16__
#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
#else
#define __swab16(x) \
(__builtin_constant_p((__u16)(x)) ? \
___constant_swab16(x) : \
__fswab16(x))
#endif
/**
* __swab32 - return a byteswapped 32-bit value
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP32__
#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
#else
#define __swab32(x) \
(__builtin_constant_p((__u32)(x)) ? \
___constant_swab32(x) : \
__fswab32(x))
#endif
/**
* __swab64 - return a byteswapped 64-bit value
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP64__
#define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
#else
#define __swab64(x) \
(__builtin_constant_p((__u64)(x)) ? \
___constant_swab64(x) : \
__fswab64(x))
#endif
static __always_inline unsigned long __swab(const unsigned long y)
{
#if __BITS_PER_LONG == 64
return __swab64(y);
#else /* __BITS_PER_LONG == 32 */
return __swab32(y);
#endif
}
/**
* __swahw32 - return a word-swapped 32-bit value
* @x: value to wordswap
*
* __swahw32(0x12340000) is 0x00001234
*/
#define __swahw32(x) \
(__builtin_constant_p((__u32)(x)) ? \
___constant_swahw32(x) : \
__fswahw32(x))
/**
* __swahb32 - return a high and low byte-swapped 32-bit value
* @x: value to byteswap
*
* __swahb32(0x12345678) is 0x34127856
*/
#define __swahb32(x) \
(__builtin_constant_p((__u32)(x)) ? \
___constant_swahb32(x) : \
__fswahb32(x))
/**
* __swab16p - return a byteswapped 16-bit value from a pointer
* @p: pointer to a naturally-aligned 16-bit value
*/
static __always_inline __u16 __swab16p(const __u16 *p)
{
#ifdef __arch_swab16p
return __arch_swab16p(p);
#else
return __swab16(*p);
#endif
}
/**
* __swab32p - return a byteswapped 32-bit value from a pointer
* @p: pointer to a naturally-aligned 32-bit value
*/
static __always_inline __u32 __swab32p(const __u32 *p)
{
#ifdef __arch_swab32p
return __arch_swab32p(p);
#else
return __swab32(*p);
#endif
}
/**
* __swab64p - return a byteswapped 64-bit value from a pointer
* @p: pointer to a naturally-aligned 64-bit value
*/
static __always_inline __u64 __swab64p(const __u64 *p)
{
#ifdef __arch_swab64p
return __arch_swab64p(p);
#else
return __swab64(*p);
#endif
}
/**
* __swahw32p - return a wordswapped 32-bit value from a pointer
* @p: pointer to a naturally-aligned 32-bit value
*
* See __swahw32() for details of wordswapping.
*/
static inline __u32 __swahw32p(const __u32 *p)
{
#ifdef __arch_swahw32p
return __arch_swahw32p(p);
#else
return __swahw32(*p);
#endif
}
/**
* __swahb32p - return a high and low byteswapped 32-bit value from a pointer
* @p: pointer to a naturally-aligned 32-bit value
*
* See __swahb32() for details of high/low byteswapping.
*/
static inline __u32 __swahb32p(const __u32 *p)
{
#ifdef __arch_swahb32p
return __arch_swahb32p(p);
#else
return __swahb32(*p);
#endif
}
/**
* __swab16s - byteswap a 16-bit value in-place
* @p: pointer to a naturally-aligned 16-bit value
*/
static inline void __swab16s(__u16 *p)
{
#ifdef __arch_swab16s
__arch_swab16s(p);
#else
*p = __swab16p(p);
#endif
}
/**
* __swab32s - byteswap a 32-bit value in-place
* @p: pointer to a naturally-aligned 32-bit value
*/
static __always_inline void __swab32s(__u32 *p)
{
#ifdef __arch_swab32s
__arch_swab32s(p);
#else
*p = __swab32p(p);
#endif
}
/**
* __swab64s - byteswap a 64-bit value in-place
* @p: pointer to a naturally-aligned 64-bit value
*/
static __always_inline void __swab64s(__u64 *p)
{
#ifdef __arch_swab64s
__arch_swab64s(p);
#else
*p = __swab64p(p);
#endif
}
/**
* __swahw32s - wordswap a 32-bit value in-place
* @p: pointer to a naturally-aligned 32-bit value
*
* See __swahw32() for details of wordswapping
*/
static inline void __swahw32s(__u32 *p)
{
#ifdef __arch_swahw32s
__arch_swahw32s(p);
#else
*p = __swahw32p(p);
#endif
}
/**
* __swahb32s - high and low byteswap a 32-bit value in-place
* @p: pointer to a naturally-aligned 32-bit value
*
* See __swahb32() for details of high and low byte swapping
*/
static inline void __swahb32s(__u32 *p)
{
#ifdef __arch_swahb32s
__arch_swahb32s(p);
#else
*p = __swahb32p(p);
#endif
}
#endif /* _UAPI_LINUX_SWAB_H */