Re: [PATCH] powerpc: enforce a non-spe kernel build even on broken compilers

[Kumar Gala <galak@kernel.crashing.org>]

On Oct 24, 2008, at 6:51 PM, Nate Case wrote:

> On Fri, 2008-10-17 at 09:02 -0500, Nate Case wrote:
>>> With this patch it compiles and boots fine.
>>> The option -mabi=no-spe is not required.
>>
>> Please don't accept this patch yet.  My past testing showed that
>> "-mabi=no-spe" was required for my toolchain.  I'll go back and  
>> double
>> check though.
>
> OK, I went back and re-tested.
>
> Kernel: 2.6.27
> CPU: MPC8572
> Toolchain:
>    Cross-compiler built using crosstool-ng
>    gcc 4.3.1, default target CFLAGS include '-mabi=spe -mspe'
>    binutils 2.18.90 snapshot (built with --enable-spe=yes)
>
> Kbuild flags                    Result
> ------------                    ------
> -mno-spe (*)                    FAILED
> -mno-spe -mabi=no-spe           FAILED
> -mno-spe -mspe=no               OK
> -mspe=no                        OK
>
> (*) 2.6.27 default
>
> In the failure case, the kernel would repeatedly dump out "SPE used in
> kernel (task=xxxxxxxx, pc=xxxxxxxx)".
>
> I think I was fooled before because I added _both_ "-mspe=no" and
> "-mabi=no-spe" to my KBUILD_CFLAGS and saw the problem go away.   
> Since I
> trusted the documentation that -mspe=no and -mno-spe were the same, I
> assumed that -mabi=no-spe was the key.
>
> So, I've changed my mind.  I now agree with Sebastian that
> "-mabi=no-spe" is not required.  "-mno-spe -mspe=no" is probably the
> safe way to go.
>
> -- 
> Nate Case <ncase@xes-inc.com>

thanks for testing this all out.

I'll submit a patch to remove the -mabi=.*spe.* foo.

- k