Bug 215658 - arch/powerpc/mm/mmu_context.o Assembler messages: Error: unrecognized opcode: `dssall' (PowerMac G4)

[Christophe Leroy]

Hi,

Le 10/03/2022 à 11:39, Thorsten Leemhuis a écrit :
> Hi, this is your Linux kernel regression tracker.
> 
> I noticed a regression report in bugzilla.kernel.org that afaics nobody
> acted upon since it was reported about a week ago, that's why I decided
> to forward it to the lists and a few relevant people to the CC. To quote
> from the ticket:

I already looked at it when the ticket was opened and that's a bit puzzling.

With v5.16.12 and the config file in the bug report I have no such problem:

   CC      arch/powerpc/mm/fault.o
   CC      arch/powerpc/mm/mem.o
   CC      arch/powerpc/mm/pgtable.o
   CC      arch/powerpc/mm/mmap.o
   CC      arch/powerpc/mm/maccess.o
   CC      arch/powerpc/mm/pageattr.o
   CC      arch/powerpc/mm/init_32.o
   CC      arch/powerpc/mm/pgtable_32.o
   CC      arch/powerpc/mm/pgtable-frag.o
   CC      arch/powerpc/mm/ioremap.o
   CC      arch/powerpc/mm/ioremap_32.o
   CC      arch/powerpc/mm/init-common.o
   CC      arch/powerpc/mm/drmem.o
   CC      arch/powerpc/mm/cacheflush.o
   CC      arch/powerpc/mm/book3s32/mmu.o
   CC      arch/powerpc/mm/book3s32/mmu_context.o
   AS      arch/powerpc/mm/book3s32/hash_low.o
   CC      arch/powerpc/mm/book3s32/tlb.o
   CC      arch/powerpc/mm/book3s32/kuep.o
   CC      arch/powerpc/mm/book3s32/kuap.o
   AR      arch/powerpc/mm/book3s32/built-in.a
   CC      arch/powerpc/mm/ptdump/ptdump.o
   CC      arch/powerpc/mm/ptdump/shared.o
   AR      arch/powerpc/mm/ptdump/built-in.a
   CC      arch/powerpc/mm/mmu_context.o
   AR      arch/powerpc/mm/built-in.a


The bug is puzzling because it says the problem is introduced by commit 
d51f86cfd8e3 ("powerpc/mm: Switch obsolete dssall to .long") whereas the 
purpose of that commit is exactly to fix the issue you are reporting.

And as far as I can see that commit is not in v5.16.12, so my feeling is 
that somethings wrong with the bug report.

By the way I think that cherry-picking that commit into v5.16.12 should 
fix it.

Christophe


> 
>> 5.16.12 kernel build for my G4 DP on my Talos II fails with:
>>
>> [...]
>>    CC      arch/powerpc/mm/init_32.o
>>    CC      arch/powerpc/mm/pgtable_32.o
>>    CC      arch/powerpc/mm/pgtable-frag.o
>>    CC      arch/powerpc/mm/ioremap.o
>>    CC      arch/powerpc/mm/ioremap_32.o
>>    CC      arch/powerpc/mm/init-common.o
>>    CC      arch/powerpc/mm/mmu_context.o
>> {standard input}: Assembler messages:
>> {standard input}:30: Error: unrecognized opcode: `dssall'
>> make[2]: *** [scripts/Makefile.build:287: arch/powerpc/mm/mmu_context.o] Fehler 1
>> make[1]: *** [scripts/Makefile.build:549: arch/powerpc/mm] Fehler 2
>> make: *** [Makefile:1846: arch/powerpc] Error 2
>>
>> This seems to have been introduced by commit d51f86cfd8e378d4907958db77da3074f6dce3ba "powerpc/mm: Switch obsolete dssall to .long"
>>
>> Reverting this commit fixes the build for my G4.
> 
> Could somebody take a look into this? Or was this discussed somewhere
> else already? Or even fixed?
> 
> Anyway, to get this tracked:
> 
> #regzbot introduced: d51f86cfd8e378d4907958db77da3074f6dce3ba
> #regzbot from: Erhard F <erhard_f at mailbox.org>
> #regzbot title:  arch/powerpc/mm/mmu_context.o Assembler messages:
> Error: unrecognized opcode: `dssall' (PowerMac G4)
> #regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215658
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> 
> P.S.: As the Linux kernel's regression tracker I'm getting a lot of
> reports on my table. I can only look briefly into most of them and lack
> knowledge about most of the areas they concern. I thus unfortunately
> will sometimes get things wrong or miss something important. I hope
> that's not the case here; if you think it is, don't hesitate to tell me
> in a public reply, it's in everyone's interest to set the public record
> straight.
>