Re: [PATCH] MIPS: lib: prefetch ahead in csum_partial()

[Geert Uytterhoeven]

Hi Maciej,

On Mon, 19 Oct 2026 at 01:26, Maciej W. Rozycki <macro@xxxxxxxxxxx> wrote:
> On Tue, 13 Oct 2026, kernel test robot wrote:
> > config: mips-rbtx49xx_defconfig (https://download.01.org/0day-ci/archive/20261013/202610131201.wWk11MLy-lkp@xxxxxxxxx/config)
> > compiler: mips-linux-gcc (GCC) 16.1.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261013/202610131201.wWk11MLy-lkp@xxxxxxxxx/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202610131201.wWk11MLy-lkp@xxxxxxxxx/
> >
> > All errors (new ones prefixed by >>):
> >
> >    Assembler messages:
> > >> arch/mips/lib/csum_partial.S:202: Error: opcode not supported on this processor: r4600 (mips3) `pref 0,0x100($4)'
> >    arch/mips/lib/csum_partial.S:203: Error: opcode not supported on this processor: r4600 (mips3) `pref 0,0x120($4)'
> >    arch/mips/lib/csum_partial.S:204: Error: opcode not supported on this processor: r4600 (mips3) `pref 0,0x140($4)'
> >    arch/mips/lib/csum_partial.S:205: Error: opcode not supported on this processor: r4600 (mips3) `pref 0,0x160($4)'
>
>  So oddly enough we're missing Tx49 support in the toolchain and we've
> only managed to survive with CPU_HAS_PREFETCH enabled for CPU_TX49XX
> because it also implies DMA_NONCOHERENT via MACH_TX49XX -> MACH_TXX9,
> which in turn disables stuff in arch/mips/lib/memcpy.S.
>
>  Quite straighforward to fix in binutils since docs are available (as in:
> I have a copy), but do we have any users?  Geert?

Yes, I still boot test rbtx4927 regularly.
I never touched binutils sources, though...

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds