[OpenBIOS] [PATCH] ppc: force target CPU

[Cole Robinson]

On 12/29/2015 11:43 AM, Mark Cave-Ayland wrote:
> On 22/11/15 11:54, Mark Cave-Ayland wrote:
> 
> (Add Hervé to CC)
> 
>> On 21/11/15 16:00, Laurent Vivier wrote:
>>
>>> With gcc-5.2 default target is power7.
>>> As openbios targets PowerMacs G3/G4/G5, force
>>> gcc target to be G3 (32bit) or G5 (64bit).
>>>
>>> Signed-off-by: Laurent Vivier <laurent at vivier.eu>
>>> ---
>>>  config/scripts/switch-arch | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/config/scripts/switch-arch b/config/scripts/switch-arch
>>> index 38d263d..bcf807a 100755
>>> --- a/config/scripts/switch-arch
>>> +++ b/config/scripts/switch-arch
>>> @@ -265,7 +265,7 @@ for ARCH in $arch_list; do
>>>          ppc)
>>>          select_prefix powerpc powerpc64
>>>          if [ "$unix" = "no" ]; then
>>> -            CFLAGS="-m32 -msoft-float -fno-builtin-bcopy -fno-builtin-log2"
>>> +            CFLAGS="-m32 -mcpu=G3 -msoft-float -fno-builtin-bcopy -fno-builtin-log2"
>>>              AS_FLAGS="-m32"
>>>          else
>>>              CFLAGS="-fno-builtin"
>>> @@ -275,7 +275,7 @@ for ARCH in $arch_list; do
>>>  
>>>          ppc64)
>>>          select_prefix powerpc64
>>> -        CFLAGS="-Wa,-a64 -m64 -msoft-float -fno-builtin"
>>> +        CFLAGS="-Wa,-a64 -m64 -mcpu=G5 -msoft-float -fno-builtin"
>>>          AS_FLAGS="-Wa,-a64"
>>>          ;;
>>>  
>>
>> Great work! Andreas, I'd be much happier if you could review/commit this
>> (or at least give a Reviewed-by) as this is a little bit out of my area
>> of knowledge...
> 
> After some further research, there are currently 2 reasons that make me
> feel we should be targeting earlier CPUs than the G3 for 32-bit OpenBIOS
> builds: firstly there are some people trying to emulate PPC 604 CPUs
> with QEMU/KVM which currently hangs in OpenBIOS, and secondly there has
> been talk of switching over QEMU's PReP machine from OHW to OpenBIOS
> instead.
> 
> To that end the minimum supported CPU for PPC needs to be 602 and so
> with this in mind, I've lightly tested the attached patch which seems to
> work here - Cole, does this work on your compiler setup? If so, I think
> this is the option I would like to apply upstream.
> 

That patch also fixes the build on fedora 23.

Thanks,
Cole