Re: TCPv4 checksum errors

[Paul Mackerras <paulus@cs.anu.edu.au>]

Geert Uytterhoeven <Geert.Uytterhoeven@cs.kuleuven.ac.be> wrote:

> In the mean time I got this from a `new' PPC hacker. I haven't tried it yet
> (still have to manually calculate checksums for my bad packets, too, sigh).

> diff -ur linux/include/asm-ppc/checksum.h linux/include/asm-ppc/checksum.h
> --- linux/include/asm-ppc/checksum.h Thu Apr 23 02:35:41 1998
> +++ linux/include/asm-ppc/checksum.h    Tue Dec 22 16:19:49 1998
> @@ -83,13 +83,13 @@
>                            unsigned int sum)
>  {
>      __asm__("
> -   add %0,%0,%1
> -   add %0,%0,%2
> -   add %0,%0,%0
> -   addi %0,%0,0
> +   addc %0,%0,%1
> +   adde %0,%0,%2
> +   adde %0,%0,%3
> +   addze %0,%0
>     "
>     : "=r" (sum)
> -   : "r" (daddr), "r"(saddr), "r"((ntohs(len)<<16)+proto*256), "0"(sum));
> +   : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
>      return sum;
>  }

Aargh, I checked arch/ppc/lib/checksum.S thoroughly but I missed this
one!  Of course it needs to be addc/adde/adde/addze.  Kudos to Petr
Vandrovec (good spotting, as Linus would say).

Paul.

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