Re: [GIT PULL -tip v3] fix 39 'make headers_check' warnings

Jaswinder Singh Rajput
2009-01-19T02:11:06Z

On Sun, 2009-01-18 at 19:50 +0100, Ingo Molnar wrote:
>
> static inline __attribute_const__ __u32 __arch_swab32(__u32 val)
> {
> #ifdef __i386__
> +#ifdef __KERNEL__
> # ifdef CONFIG_X86_BSWAP
> asm("bswap %0" : "=r" (val) : "0" (val));
> # else
> @@ -16,7 +19,13 @@ static inline __attribute_const__ __u32 __arch_swab32(__u32 val)
> : "=q" (val)
> : "0" (val));
> # endif
> -
> +#else /* __KERNEL__ */
> + asm("xchgb %b0,%h0\n\t" /* swap lower bytes */
> + "rorl $16,%0\n\t" /* swap words */
> + "xchgb %b0,%h0" /* swap higher bytes */
> + : "=q" (val)
> + : "0" (val));
> +#endif /* __KERNEL__ */
> #else /* __i386__ */
> asm("bswapl %0"
> : "=r" (val)
> @@ -37,6 +46,7 @@ static inline __attribute_const__ __u64 __arch_swab64(__u64 val)
> __u64 u;
> } v;
> v.u = val;
> +#ifdef __KERNEL__
> # ifdef CONFIG_X86_BSWAP
> asm("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
> : "=r" (v.s.a), "=r" (v.s.b)
> @@ -48,6 +58,13 @@ static inline __attribute_const__ __u64 __arch_swab64(__u64 val)
> : "=r" (v.s.a), "=r" (v.s.b)
> : "0" (v.s.a), "1" (v.s.b));
> # endif
> +#else /* __KERNEL__ */
> + v.s.a = __arch_swab32(v.s.a);
> + v.s.b = __arch_swab32(v.s.b);
> + asm("xchgl %0,%1"
> + : "=r" (v.s.a), "=r" (v.s.b)
> + : "0" (v.s.a), "1" (v.s.b));
> +#endif /* __KERNEL__ */
> return v.u;
> #else /* __i386__ */
> asm("bswapq %0"
>
>
> why does such a change introduce new code? It is duplicating existing code
> instead of cleaning it all up.
>

That's why I was requesting you to check asm/swab.h because I was in
doubt whether we need these functions in userspace or not.

If we do not need these functions in userspace then I will clean these
up.

--
JSR