[PATCH kernel] powerpc/makefile: Do not redefine $(CPP) for preprocessor

[Christophe Leroy]

Le 23/04/2021 à 00:58, Daniel Axtens a écrit :
>> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>> index c9d2c7825cd6..3a2f2001c62b 100644
>> --- a/arch/powerpc/Makefile
>> +++ b/arch/powerpc/Makefile
>> @@ -214,7 +214,6 @@ KBUILD_CPPFLAGS	+= -I $(srctree)/arch/$(ARCH) $(asinstr)
>>   KBUILD_AFLAGS	+= $(AFLAGS-y)
>>   KBUILD_CFLAGS	+= $(call cc-option,-msoft-float)
>>   KBUILD_CFLAGS	+= -pipe $(CFLAGS-y)
>> -CPP		= $(CC) -E $(KBUILD_CFLAGS)
> 
> I was trying to check the history to see why powerpc has its own
> definition. It seems to date back at least as far as merging the two
> powerpc platforms into one, maybe it was helpful then. I agree it
> doesn't seem to be needed now.
> 

I digged a bit deaper. It has been there since the introduction of arch/ppc/ in Linux 1.3.45
At the time, there was the exact same CPP definition in arch/mips/Makefile

The CPP definition in mips disappeared is Linux 2.1.44pre3.
Since that version, ppc has been the only one with such CPP re-definition.

> Snowpatch claims that this breaks the build, but I haven't been able to
> reproduce the issue in either pmac32 or ppc64 defconfig. I have sent it
> off to a fork of mpe's linux-ci repo to see if any of those builds hit
> any issues: https://github.com/daxtens/linux-ci/actions
> 

By the way, I find snowpatch quite useless these days. It seems to delete the reports a few minutes 
after the test. We are less than one day after the patch was submitted and the report of the build 
failures are already gone.

Christophe