[PATCH] ARM: fix vdsomunge depends on glibc specific byteswap.h

[Ard Biesheuvel]

On 30 September 2015 at 17:56, H. Nikolaus Schaller <hns at goldelico.com> wrote:
> If the host toolchain is not glibc based then the arm kernel build
> fails with
>
>  HOSTCC  arch/arm/vdso/vdsomunge
>  arch/arm/vdso/vdsomunge.c:48:22: fatal error: byteswap.h: No such file or directory
>
> Observed with omap2plus_defconfig and compile on Mac OS X with arm ELF
> cross-compiler.
>
> Reason: byteswap.h is a glibc only header.
>
> Changed to detect the host and include the right file as described at:
>
>  https://bugs.freedesktop.org/show_bug.cgi?id=8882
>
> Tested to compile on Mac OS X 10.9.5 host.
>
> Signed-off-by: H. Nikolaus Schaller <hns at goldelico.com>
> ---
> arch/arm/vdso/vdsomunge.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/arch/arm/vdso/vdsomunge.c b/arch/arm/vdso/vdsomunge.c
> index aedec81..5364cea 100644
> --- a/arch/arm/vdso/vdsomunge.c
> +++ b/arch/arm/vdso/vdsomunge.c
> @@ -45,7 +45,25 @@
>  * it does.
>  */
>
> +#if defined(__linux__)
> #include <byteswap.h>
> +#elif defined(__OpenBSD__)
> +#include <sys/endian.h>
> +#define bswap_16 __swap16
> +#define bswap_32 __swap32
> +#define bswap_64 __swap64
> +#elif defined(__APPLE__)
> +#include <libkern/OSByteOrder.h>
> +#define bswap_16 OSSwapInt16
> +#define bswap_32 OSSwapInt32
> +#define bswap_64 OSSwapInt64
> +#else
> +#include <sys/endian.h>
> +#define bswap_16 bswap16
> +#define bswap_32 bswap32
> +#define bswap_64 bswap64
> +#endif
> +

Have you tried this?

#define bswap_16 __builtin_bswap16
#define bswap_32 __builtin_bswap32
#define bswap_64 __builtin_bswap64

https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html