Re: [PATCH v4] ARM: fix vdsomunge not to depend on glibc specific byteswap.h

[Nathan Lynch]

On 10/16/2015 01:38 AM, H. Nikolaus Schaller wrote:
> diff --git a/arch/arm/vdso/vdsomunge.c b/arch/arm/vdso/vdsomunge.c
> index aedec81..0cebd98 100644
> --- a/arch/arm/vdso/vdsomunge.c
> +++ b/arch/arm/vdso/vdsomunge.c
> @@ -45,7 +45,6 @@
>   * it does.
>   */
>  
> -#include <byteswap.h>
>  #include <elf.h>
>  #include <errno.h>
>  #include <fcntl.h>
> @@ -59,6 +58,16 @@
>  #include <sys/types.h>
>  #include <unistd.h>
>  
> +#define swab16(x) \
> +	((((x) & 0x00ff) << 8) | \
> +	 (((x) & 0xff00) >> 8))
> +
> +#define swab32(x) \
> +	((((x) & 0x000000ff) << 24) | \
> +	 (((x) & 0x0000ff00) <<  8) | \
> +	 (((x) & 0x00ff0000) >>  8) | \
> +	 (((x) & 0xff000000) << 24))
> +
>  #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
>  #define HOST_ORDER ELFDATA2LSB
>  #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> @@ -104,17 +113,17 @@ 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;
>  }

I think this looks good now and it checks out in my local testing.
Thanks for your persistence.

Assuming Russell has no further comments I'll put this in his patch
system later today.

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