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

[Christophe Leroy]

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')")


Thanks
Christophe