On Sunday 28 August 2022 17:43:53 Christophe Leroy wrote:

Le 28/08/2022 à 19:41, Pali Rohár a écrit :

quoted

On Sunday 28 August 2022 17:39:25 Christophe Leroy wrote:

quoted

Le 28/08/2022 à 19:33, Christophe Leroy a écrit :

quoted

Le 28/08/2022 à 11:56, Pali Rohár a écrit :

quoted

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.

I see... Will you prepare this fixup for your previous patch?

And I think that following construct

  $(call cc-option,-mcpu=$(CONFIG_TARGET_CPU))

should be changed just to

  -mcpu=$(CONFIG_TARGET_CPU)

Because if user specified that want build for specific target CPU, it
should not be silently ignored.