Re: [PATCH v4 00/17] powerpc: Make hash MMU code build configurable

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 26/11/2021 à 01:55, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of November 26, 2021 3:35 am:
>>
>>
>> Le 25/11/2021 à 17:35, Christophe Leroy a écrit :
>>>
>>>
>>> Le 25/11/2021 à 13:50, Nicholas Piggin a écrit :
>>>> Now that there's a platform that can make good use of it, here's
>>>> a series that can prevent the hash MMU code being built for 64s
>>>> platforms that don't need it.
>>>
>>> # CONFIG_PPC_64S_HASH_MMU is not set
>>>
>>>
>>> <stdin>:1559:2: warning: #warning syscall futex_waitv not implemented
>>> [-Wcpp]
>>> arch/powerpc/platforms/cell/spu_base.c: In function '__spu_kernel_slb':
>>> arch/powerpc/platforms/cell/spu_base.c:215:38: error: 'mmu_linear_psize'
>>> undeclared (first use in this function); did you mean 'mmu_virtual_psize'?
>>>     215 |                 llp = mmu_psize_defs[mmu_linear_psize].sllp;
>>>         |                                      ^~~~~~~~~~~~~~~~
>>>         |                                      mmu_virtual_psize
>>> arch/powerpc/platforms/cell/spu_base.c:215:38: note: each undeclared
>>> identifier is reported only once for each function it appears in
>>> make[3]: *** [scripts/Makefile.build:287:
>>> arch/powerpc/platforms/cell/spu_base.o] Error 1
>>> make[2]: *** [scripts/Makefile.build:549: arch/powerpc/platforms/cell]
>>> Error 2
>>> make[1]: *** [scripts/Makefile.build:549: arch/powerpc/platforms] Error 2
>>> make: *** [Makefile:1846: arch/powerpc] Error 2
>>>
>>>
>>
>>
>> With CONFIG_SPU_BASE removed, the above voids and I get to the final
>> link with the following errors:
> 
> This is building cell platform with POWER9 CPU and !HASH?

I took ppc64_defconfig, changed CPU to POWER9 and removed VIRTUALIZATION 
and removed CONFIG_PPC_64S_HASH_MMU.

> 
> We don't have to make that build, just prevent the config. I had that in
> a previous version which also had platforms select hash, but we went to
> just CPU. But now there's no constraint that prevents cell+POWER9 even
> though it doesn't make sense.
> 
> Not sure the best way to fix it. I'll think about it.
> 

Force selection of CONFIG_PPC_64S_HASH_MMU by the CELL platform ?