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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Sat, 16 Feb 2019 11:25:03 +0900
Message-ID: <CAK7LNAQUEivnhFnmkP+5uCHRJcYWDtK_fm2gB0rsbzGv1taBCg@mail.gmail.com>
Subject: Re: [PATCH] powerpc: use $(origin ARCH) to select KBUILD_DEFCONFIG
To:     Mathieu Malaterre <malat@debian.org>
Cc:     linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Sat, Feb 16, 2019 at 1:11 AM Mathieu Malaterre <malat@debian.org> wrote:
>
> On Fri, Feb 15, 2019 at 10:41 AM Masahiro Yamada
> <yamada.masahiro@socionext.com> wrote:
> >
> > I often test all Kconfig commands for all architectures. To ease my
> > workflow, I want 'make defconfig' at least working without any cross
> > compiler.
> >
> > Currently, arch/powerpc/Makefile checks CROSS_COMPILE to decide the
> > default defconfig source.
> >
> > If CROSS_COMPILE is unset, it is likely to be the native build, so
> > 'uname -m' is useful to choose the defconfig. If CROSS_COMPILE is set,
> > the user is cross-building (i.e. 'uname -m' is probably x86_64), so
> > it falls back to ppc64_defconfig. Yup, make sense.
> >
> > However, I want to run 'make ARCH=* defconfig' without setting
> > CROSS_COMPILE for each architecture.
> >
> > My suggestion is to check $(origin ARCH).
> >
> > When you cross-compile the kernel, you need to set ARCH from your
> > environment or from the command line.
> >
> > For the native build, you do not need to set ARCH. The default in
> > the top Makefile is used:
> >
> >   ARCH            ?= $(SUBARCH)
> >
> > Hence, $(origin ARCH) returns 'file'.
> >
> > Before this commit, 'make ARCH=powerpc defconfig' failed:
>
> In case you have not seen it, please check:
>
> http://patchwork.ozlabs.org/patch/1037835/


I did not know that because I do not subscribe to ppc ML.


Michael's patch looks good to me.


If you mimic x86, the following will work:


diff --git a/Makefile b/Makefile
index 86cf35d..eb9552d 100644
--- a/Makefile
+++ b/Makefile
@@ -356,6 +356,11 @@ ifeq ($(ARCH),sh64)
        SRCARCH := sh
 endif

+# Additional ARCH settings for powerpc
+ifneq ($(filter ppc%,$(ARCH)),)
+       SRCARCH := powerpc
+endif
+
 KCONFIG_CONFIG ?= .config
 export KCONFIG_CONFIG

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 488c9ed..ff01fef 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -34,10 +34,10 @@ ifdef CONFIG_PPC_BOOK3S_32
 KBUILD_CFLAGS          += -mcpu=powerpc
 endif

-ifeq ($(CROSS_COMPILE),)
-KBUILD_DEFCONFIG := $(shell uname -m)_defconfig
-else
+ifeq ($(ARCH),powerpc)
 KBUILD_DEFCONFIG := ppc64_defconfig
+else
+KBUILD_DEFCONFIG := $(ARCH)_defconfig
 endif

 ifdef CONFIG_PPC64
diff --git a/scripts/subarch.include b/scripts/subarch.include
index 6506828..c98323f 100644
--- a/scripts/subarch.include
+++ b/scripts/subarch.include
@@ -8,6 +8,6 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e
s/x86_64/x86/ \
                                  -e s/sun4u/sparc64/ \
                                  -e s/arm.*/arm/ -e s/sa110/arm/ \
                                  -e s/s390x/s390/ -e s/parisc64/parisc/ \
-                                 -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
+                                 -e s/mips.*/mips/ \
                                  -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ \
                                  -e s/riscv.*/riscv/)


--
Best Regards
Masahiro Yamada