[PATCH] powerpc: e500: Fix compilation with gcc e500 compiler

[Christophe Leroy]

Le 11/07/2022 à 23:48, Segher Boessenkool a écrit :
> Hi!
> 
> On Mon, Jul 11, 2022 at 05:32:09PM +0000, Christophe Leroy wrote:
>> Le 11/07/2022 à 18:14, Segher Boessenkool a écrit :
>>>>      CC      arch/powerpc/kernel/irq.o
>>>> {standard input}: Assembler messages:
>>>> {standard input}:3535: Error: unrecognized opcode: `wrteei'
>>>> {standard input}:5608: Error: unrecognized opcode: `wrteei'
>>>
>>> What -mcpu= did it use here?
>>
>> -mcpu=powerpc64
>>
>>> wrteei is not a PowerPC insn (it is BookE, instead), so it is not
>>> recognised without an appropriate -mcpu=.
>>>
>>>> If I select the e5500 (without altivec) or e6500 I get:
>>>>
>>>>      CC      arch/powerpc/kernel/io.o
>>>> {standard input}: Assembler messages:
>>>> {standard input}:381: Error: unrecognized opcode: `eieio'
>>>
>>> Same question.  eieio is a base PowerPC instruction, so this one is
>>> "interesting" :-)
>>
>> -mcpu=e500mc64 (for e5500)
>> -mcpu=e6500 (for e6500)
>>
>> I had to replace 'eieio' instruction by 'mbar' instruction.
> 
> I saw some patches fly by...  you have it all fixed with that?

Yes it fixed all build failures with GCC 12.


> 
>> Seems like binutils added 'eieio' to e500 in 2010 via commit
>> e01d869a3be, but it seems it is only for the 85xx, not for the others.
> 
> I believe the eieio instruction is disabled on some e500 models, because
> it does not work correctly, so EIEIO_EN=1 cannot work, something like
> that?

Don't know.

It is also disabled on 405 and 440.

That's new with GCC 12.

Christophe