Re: [PATCH v2] ARM: fix vdsomunge not to depend on glibc specific byteswap.h

[H. Nikolaus Schaller]

ping.

Am 03.10.2015 um 22:46 schrieb H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>:

> 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.
> 
> Solution: replace by private byte-swapping macros (taken from
> arch/mips/boot/elf2ecoff.c)
> 
> Tested to compile on Mac OS X 10.9.5 host.
> 
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> ---
> arch/arm/vdso/vdsomunge.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/vdso/vdsomunge.c b/arch/arm/vdso/vdsomunge.c
> index aedec81..27a9a0b 100644
> --- a/arch/arm/vdso/vdsomunge.c
> +++ b/arch/arm/vdso/vdsomunge.c
> @@ -45,7 +45,18 @@
> * it does.
> */
> 
> -#include <byteswap.h>
> +#define swab16(x) \
> +	((unsigned short)( \
> +		(((unsigned short)(x) & (unsigned short)0x00ffU) << 8) | \
> +		(((unsigned short)(x) & (unsigned short)0xff00U) >> 8) ))
> +
> +#define swab32(x) \
> +	((unsigned int)( \
> +		(((unsigned int)(x) & (unsigned int)0x000000ffUL) << 24) | \
> +		(((unsigned int)(x) & (unsigned int)0x0000ff00UL) <<  8) | \
> +		(((unsigned int)(x) & (unsigned int)0x00ff0000UL) >>  8) | \
> +		(((unsigned int)(x) & (unsigned int)0xff000000UL) >> 24) ))
> +
> #include <elf.h>
> #include <errno.h>
> #include <fcntl.h>
> @@ -104,17 +115,17 @@ static void cleanup(void)
> 
> static Elf32_Word read_elf_word(Elf32_Word word, bool swap)
> {
> -	return swap ? bswap_32(word) : word;
> +	return swap ? swab32(word) : word;
> }
> 
> static Elf32_Half read_elf_half(Elf32_Half half, bool swap)
> {
> -	return swap ? bswap_16(half) : half;
> +	return swap ? swab16(half) : half;
> }
> 
> static void write_elf_word(Elf32_Word val, Elf32_Word *dst, bool swap)
> {
> -	*dst = swap ? bswap_32(val) : val;
> +	*dst = swap ? swab32(val) : val;
> }
> 
> int main(int argc, char **argv)
> -- 
> 2.5.1
> 

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