Thread (30 messages) 30 messages, 2 authors, 2023-02-20

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

From: Pali Rohár <pali@kernel.org>
Date: 2022-12-24 17:45:07
Also in: lkml

On Thursday 08 December 2022 19:57:39 Christophe Leroy wrote:
Le 08/12/2022 à 20:16, Pali Rohár a écrit :
quoted
On Sunday 28 August 2022 17:43:53 Christophe Leroy wrote:
quoted
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.
With "[PATCH v1] powerpc/64: Set default CPU in Kconfig" patch from
https://lore.kernel.org/linuxppc-dev/3fd60c2d8a28668a42b766b18362a526ef47e757.1670420281.git.christophe.leroy@csgroup.eu/ (local)
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@kernel.org/

Christophe
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