[PATCH v1 5/5] powerpc/64e: Fix build failure with GCC 12 (unrecognized opcode: `wrteei')

[Michael Ellerman]

Christophe Leroy <christophe.leroy at csgroup.eu> writes:
> Le 11/12/2022 à 18:32, Pali Rohár a écrit :
>> On Monday 11 July 2022 16:19:33 Christophe Leroy wrote:
>>> With GCC 12, corenet64_smp_defconfig leads to the following build errors:
>>>
>>>    CC      arch/powerpc/kernel/irq.o
>>> {standard input}: Assembler messages:
>>> {standard input}:3616: Error: unrecognized opcode: `wrteei'
>>> {standard input}:5689: Error: unrecognized opcode: `wrteei'
>>>    CC      arch/powerpc/kernel/pmc.o
>>> {standard input}: Assembler messages:
>>> {standard input}:42: Error: unrecognized opcode: `mfpmr'
>>> {standard input}:53: Error: unrecognized opcode: `mtpmr'
>>>    CC      arch/powerpc/kernel/io.o
>>> {standard input}: Assembler messages:
>>> {standard input}:376: Error: unrecognized opcode: `mbar'
>>> ...
>>>    CC      arch/powerpc/mm/nohash/book3e_hugetlbpage.o
>>> {standard input}: Assembler messages:
>>> {standard input}:291: Error: unrecognized opcode: `tlbsx'
>>> {standard input}:482: Error: unrecognized opcode: `tlbwe'
>>> {standard input}:608: Error: unrecognized opcode: `lbarx'
>>> {standard input}:608: Error: unrecognized opcode: `stbcx.'
>>>
>>> -mpcu=powerpc64 cannot be used anymore for book3e, it must be a booke CPU.
>>>
>>> But then we get:
>>>
>>>    CC      arch/powerpc/lib/xor_vmx.o
>>> cc1: error: AltiVec not supported in this target
>>>
>>> Altivec is not supported with -mcpu=e5500 so don't allow selection
>>> of altivec when e5500 is selected.
>>>
>>> Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
>>> ---
>>>   arch/powerpc/Makefile                  | 8 +-------
>>>   arch/powerpc/platforms/Kconfig.cputype | 8 ++++----
>>>   2 files changed, 5 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>>> index d54e1fe03551..02742facf895 100644
>>> --- a/arch/powerpc/Makefile
>>> +++ b/arch/powerpc/Makefile
>>> @@ -168,13 +168,7 @@ endif
>>>   CFLAGS-$(CONFIG_TARGET_CPU_BOOL) += $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))
>>>   AFLAGS-$(CONFIG_TARGET_CPU_BOOL) += $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))
>>>   
>>> -# Altivec option not allowed with e500mc64 in GCC.
>>> -ifdef CONFIG_ALTIVEC
>>> -E5500_CPU := -mcpu=powerpc64
>>> -else
>>> -E5500_CPU := $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
>>> -endif
>>> -CFLAGS-$(CONFIG_E5500_CPU) += $(E5500_CPU)
>>> +CFLAGS-$(CONFIG_E5500_CPU) += $(call cc-option,-mcpu=e500mc64,-mcpu=powerpc64)
>>>   CFLAGS-$(CONFIG_E6500_CPU) += $(call cc-option,-mcpu=e6500,$(E5500_CPU))
>> 
>> Hello! I think that there is an issue. After removal of E5500_CPU
>> variable few line above, it cannot be used in CFLAGS-$(CONFIG_E6500_CPU)
>> assignment, because it is empty.
>> 
>
> Ah yes, you are right.
>
> It should be fixed by 
> https://github.com/linuxppc/linux/commit/f2636eaac7dee1d7d096cc115ff4f5111b0c508c
>
> Michael, I see the patch is in next-test. Can you add:
>
> Fixes: d6b551b8f90c ("powerpc/64e: Fix build failure with GCC 12 
> (unrecognized opcode: `wrteei')")

Yep, will do.

cheers