Re: [Qemu-devel] [PATCH] pc-bios: build OpenBIOS if possible

[Blue Swirl]

On Sun, Feb 10, 2013 at 6:42 AM, Michael Tokarev <address@hidden> wrote:
> 09.02.2013 23:01, Blue Swirl wrote:
>>
>> Check if xsltproc and Sparc32, Sparc64 and PPC compilers
>> are available. If found, rebuild OpenBIOS ROMs from submodule.
>>
>> Signed-off-by: Blue Swirl <address@hidden>
>> ---
>> A patch to OpenBIOS is also needed to support out of tree build,
>> just sent to the list.
>
> []
>
>> +# OpenBIOS needs xsltproc, and Sparc32, Sparc64 and PPC cross compilers
>> +if has xsltproc; then
>> +    if has_crossgcc "sparc" -a has_crossgcc "sparc64" -a \
>> +        \( has_crossgcc "powerpc" -o  has_crossgcc "ppc" \); then
>> +        roms="$roms openbios"
>> +    fi
>> +fi
>
>
> Do we need to be able to turn it off?  Or maybe we should just
> stop doing this by default (since binaries are already present
> in the tarball), but instead suggest user to run `make -C roms'
> if [s]he needs/wants these roms to be rebuilt?

We also build optionroms and spapr-rtas automatically, not seabios
though and there's no option to disable/enable those.

I'm not sure why we build those either except to encourage using self
built ROMs instead of the supplied binaries. I think it has more to do
with keeping in line with the spirit of open source rather than any
technical advantages.

>
> I guess this is not a question for this patch but a more general
> question.
>
> I dislike rebuilding stuff this way, in particular because current
> system may have some outdated (or too new) compiler for that stuff
> to produce somehow broken binary, because this way, the resulting
> blobs differs from ones in the tarball and comparing in attempt to
> find what has changed shows these and makes some noize, -- stuff
> like that.

This could also apply to optionroms and spapr-rtas. Clang/LLVM
assembler does not support 16 bit x86 code yet, so we already have a
workaround for that. For OpenBIOS this is also a real concern since
GCC 4.7.0 does not produce working binaries.

>
>
>> +++ b/pc-bios/openbios/Makefile
>>
>> +config-timestamp: $(SRC_PATH)/roms/openbios/config/scripts/switch-arch
>> +       mkdir build || true
>
>
> That's what `mkdir -p' if for.

Thanks, will fix. The directory could be also made by configure.

>
> Thanks,
>
> /mjt