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

[Anthony Liguori]

Blue Swirl <address@hidden> writes:

> 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.

It's all historical I guess.  We should try to build everything we can
and prefer to install that over the binaries that are shipped.

Regards,

Anthony Liguori

> 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 system may have some outdated (or too new) compiler for that stuff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.

I don't really think this is a valid argument.  If you have a broken
compiler, then you have bigger concerns then whether the blobs got built
correctly.

Regards,

Anthony Liguori

>
> 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