From: Masahiro Yamada <masahiroy@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-kbuild <linux-kbuild@vger.kernel.org>,
Helge Deller <deller@gmx.de>,
"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
Rich Felker <dalias@libc.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Vineet Gupta <vgupta@synopsys.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
"open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
Parisc List <linux-parisc@vger.kernel.org>,
Linux-sh list <linux-sh@vger.kernel.org>,
arcml <linux-snps-arc@lists.infradead.org>,
"moderated list:H8/300 ARCHITECTURE"
<uclinux-h8-devel@lists.sourceforge.jp>
Subject: Re: [PATCH] kbuild: use ?= to assign CROSS_COMPILE by arch-Makefile
Date: Mon, 12 Apr 2021 17:27:14 +0900 [thread overview]
Message-ID: <CAK7LNAR4AqtqHzDnscMtXV1KGzgHy7ZDoFFcZ=QNSv1fT+wKFg@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNATozxbhq1Q4HtiOrE87KKFEmdC7Hfp-biXYG1e_eFzHvw@mail.gmail.com>
On Mon, Apr 12, 2021 at 5:15 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Mon, Apr 12, 2021 at 4:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> >
> > Hi Yamada-san,
> >
> > On Sun, Apr 11, 2021 at 3:56 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> > > Use ?= operator to let arch/*/Makefile to assign CROSS_COMPILE only
> > > when CROSS_COMPILE is undefined.
> > >
> > > This allows arch-Makefiles to drop the ifeq ($(CROSS_COMPILE),)
> > > conditional.
> > >
> > > This slightly changes the behavior; the arch-Makefile previously
> > > overrode CROSS_COMPILE when CROSS_COMPILE has already been made empty
> > > via an environment variable as in 'export CROSS_COMPILE='.
> > >
> > > With this commit, arch-Makefle will respect the user's environment
> > > set-up, which seems to be a more correct behavior.
> > >
> > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> >
> > Thanks for your patch!
> >
> > > ---
> > >
> > > arch/arc/Makefile | 4 +---
> > > arch/h8300/Makefile | 4 +---
> > > arch/m68k/Makefile | 4 +---
> > > arch/mips/Makefile | 4 +---
> > > arch/parisc/Makefile | 6 ++----
> > > arch/sh/Makefile | 4 +---
> >
> > What about arch/xtensa/Makefile?
> >
> > > --- a/arch/m68k/Makefile
> > > +++ b/arch/m68k/Makefile
> > > @@ -17,10 +17,8 @@
> > > KBUILD_DEFCONFIG := multi_defconfig
> > >
> > > ifneq ($(SUBARCH),$(ARCH))
> > > - ifeq ($(CROSS_COMPILE),)
> > > - CROSS_COMPILE := $(call cc-cross-prefix, \
> > > + CROSS_COMPILE ?= $(call cc-cross-prefix, \
> > > m68k-linux-gnu- m68k-linux- m68k-unknown-linux-gnu-)
> > > - endif
> > > endif
> >
> > This does not seem to work as expected: my standard build scripts
> > (using "make ARCH=m68k") no longer pick up the cross-compiler,
> > but fall back to the native compiler, thus breaking the build.
>
>
> Agh, sorry, this patch does not work
> because the top Makefile exports CROSS_COMPILE.
>
> export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS
> CROSS_COMPILE LD CC
>
>
>
> Removing CROSS_COMPILE from that makes ?= work,
> but it would break other parts.
>
>
> Please ignore this patch.
>
>
>
>
> > Gr{oetje,eeting}s,
> >
> > Geert
> >
> > --
> > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> >
> > In personal conversations with technical people, I call myself a hacker. But
> > when I'm talking to journalists I just say "programmer" or something like that.
> > -- Linus Torvalds
>
The following will make this patch work, but probably it is better to
not do this...
diff --git a/Makefile b/Makefile
index cc77fd45ca64..26bf482f0d88 100644
--- a/Makefile
+++ b/Makefile
@@ -506,7 +506,7 @@ KBUILD_LDFLAGS_MODULE :=
KBUILD_LDFLAGS :=
CLANG_FLAGS :=
-export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS
CROSS_COMPILE LD CC
+export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS LD CC
export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS
LEX YACC AWK INSTALLKERNEL
export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
@@ -681,6 +681,8 @@ export RETPOLINE_VDSO_CFLAGS
include arch/$(SRCARCH)/Makefile
+export CROSS_COMPILE
+
ifdef need-config
ifdef may-sync-config
# Read in dependencies to all Kconfig* files, make sure to run syncconfig if
--
Best Regards
Masahiro Yamada
prev parent reply other threads:[~2021-04-12 8:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-11 13:55 [PATCH] kbuild: use ?= to assign CROSS_COMPILE by arch-Makefile Masahiro Yamada
2021-04-12 7:44 ` Geert Uytterhoeven
2021-04-12 8:15 ` Masahiro Yamada
2021-04-12 8:27 ` Masahiro Yamada [this message]
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