Re: [PATCH v3] powerpc/boot: Don't always pass -mcpu=powerpc when building 32-bit uImage

[Pali Rohár]

On Thursday 08 December 2022 19:57:39 Christophe Leroy wrote:
> Le 08/12/2022 à 20:16, Pali Rohár a écrit :
> > On Sunday 28 August 2022 17:43:53 Christophe Leroy wrote:
> >> Le 28/08/2022 à 19:41, Pali Rohár a écrit :
> >>> On Sunday 28 August 2022 17:39:25 Christophe Leroy wrote:
> >>>> Le 28/08/2022 à 19:33, Christophe Leroy a écrit :
> >>>>>
> >>>>>
> >>>>> Le 28/08/2022 à 11:56, Pali Rohár a écrit :
> >>>>>> When CONFIG_TARGET_CPU is specified then pass its value to the compiler
> >>>>>> -mcpu option. This fixes following build error when building kernel with
> >>>>>> powerpc e500 SPE capable cross compilers:
> >>>>>>
> >>>>>>        BOOTAS  arch/powerpc/boot/crt0.o
> >>>>>>      powerpc-linux-gnuspe-gcc: error: unrecognized argument in option
> >>>>>> ‘-mcpu=powerpc’
> >>>>>>      powerpc-linux-gnuspe-gcc: note: valid arguments to ‘-mcpu=’ are:
> >>>>>> 8540 8548 native
> >>>>>>      make[1]: *** [arch/powerpc/boot/Makefile:231:
> >>>>>> arch/powerpc/boot/crt0.o] Error 1
> >>>>>
> >>>>> corenet64_smp_defconfig :
> >>>>>
> >>>>>      BOOTAS  arch/powerpc/boot/crt0.o
> >>>>> powerpc64-linux-gcc: error: missing argument to '-mcpu='
> >>>>> make[1]: *** [arch/powerpc/boot/Makefile:237 : arch/powerpc/boot/crt0.o]
> >>>>> Erreur 1
> >>>>> make: *** [arch/powerpc/Makefile:253 : uImage] Erreur 2
> >>>>>
> >>>>>
> >>>>
> >>>> Seems like in fact, E5500_CPU and E6500_CPU are not taken into account
> >>>> in CONFIG_TARGET_CPU, and get special treatment directly in
> >>>> arch/powerpc/Makefile.
> >>>>
> >>>> This goes unnoticed because of CFLAGS-$(CONFIG_TARGET_CPU_BOOL) +=
> >>>> $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))
> >>>>
> >>>> I think we need to fix that prior to your patch.
> >>>
> >>> It looks like that CONFIG_TARGET_CPU is broken.
> >>>
> >>>     $ make ARCH=powerpc corenet64_smp_defconfig CROSS_COMPILE=powerpc64-linux-gnu-
> >>>     ...
> >>>     # configuration written to .config
> >>>
> >>>     $ grep CONFIG_TARGET_CPU .config
> >>>     CONFIG_TARGET_CPU_BOOL=y
> >>>
> >>> CONFIG_TARGET_CPU_BOOL is set but CONFIG_TARGET_CPU not!
> >>
> >> Yes, because there is no default value for E5500_CPU and E6500_CPU. We
> >> need to add one for each.
> > 
> > With "[PATCH v1] powerpc/64: Set default CPU in Kconfig" patch from
> > https://lore.kernel.org/linuxppc-dev/3fd60c2d8a28668a42b766b18362a526ef47e757.1670420281.git.christophe.leroy@xxxxxxxxxx/
> > this change does not throw above compile error anymore.
> 
> 
> That patch should land in powerpc/next soon. When it has landed, could 
> you resent this patch so that snowpatch checks the build again ?

Yes. But I'm still waiting because patch is not in powerpc/next yet.

> Because at the time being it is flagged as "failed", see 
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20220828095659.4061-1-pali@xxxxxxxxxx/
> 
> Christophe