From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Miguel Ojeda <ojeda@kernel.org>,
Fangrui Song <maskray@google.com>,
Michal Marek <michal.lkml@markovi.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Christoph Hellwig <hch@infradead.org>,
Nathan Chancellor <nathan@kernel.org>
Subject: Re: [PATCH v2 2/2] Makefile: infer CROSS_COMPILE from SRCARCH for LLVM=1 LLVM_IAS=1
Date: Fri, 23 Jul 2021 21:54:10 +0200 [thread overview]
Message-ID: <CAMuHMdXJBqrpzaSNDJgic14ESiHV6cCcb_5E-st6iniXdmm9_g@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNATLy2F-2zkHm4ENSufBT_o5p=9jc5k1K-xOV8cQf7kKDw@mail.gmail.com>
Hi Yamada-san,
On Wed, Jul 21, 2021 at 6:05 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> On Wed, Jul 21, 2021 at 4:58 AM Arnd Bergmann <arnd@kernel.org> wrote:
> > On Tue, Jul 20, 2021 at 7:43 PM Linus Torvalds
> > <torvalds@linux-foundation.org> wrote:
> > > On Tue, Jul 20, 2021 at 1:05 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> > >
> > > We do most of the other heavy lifting in this area in Kconfig anyway,
> > > why not add that compiler choice?
> > >
> > > Obviously it would be gated by the tests to see which compilers are
> > > _installed_ (and that they are valid versions), so that it doesn't ask
> > > stupid things ("do you want gcc or clang" when only one of them is
> > > installed and/or viable).
> >
> > I don't see a good way of making Kconfig options both select the
> > compiler and defining variables based on the compiler, since that
> > would mean teaching Kconfig about re-evaluating all compiler
> > dependent settings whenever the first option changes.
> >
> > I do have another idea that I think would work though.
> >
> > > Hmm? So then any "LLVM=1" thing would be about the "make config"
> > > stage, not the actual build stage.
> > >
> > > (It has annoyed me for years that if you want to cross-compile, you
> > > first have to do "make ARCH=xyz config" and then remember to do "make
> > > ARCH=xyz" for the build too, but I cross-compile so seldom that I've
> > > never really cared).
> >
> > The best thing that I have come up with is a pre-configure step, where
> > an object tree gets seeded with a makefile fragment that gets included
> > for any 'make' invocation. This would set 'ARCH=', 'CROSS_COMPILE',
> > 'CC=' and possibly any other option that gets passed to 'make' as
> > a variable and has to exist before calling 'make *config'.
>
>
> There is no need to add a hook to include such makefile fragment(s).
>
> Quite opposite, you can put your Makefile (in a different filename)
> that includes the top Makefile.
>
>
> I think this is what people are already doing:
>
>
> GNU Make looks for 'GNUmakefile', 'makefile', and 'Makefile'
> in this order.
Exactly. I only have a few source repositories, but lots of build directories
(I never build in a repo directory). Each build directory has a GNUmakefile:
build/linux-riscv-starlight$ cat GNUmakefile
MAKEARGS = ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu-
include ~/linux/default.mk
build/linux-riscv-starlight$ cat ~/linux/default.mk
MAKEFLAGS += --no-print-directory
.PHONY: all $(MAKECMDGOALS)
all := $(filter-out all Makefile,$(MAKECMDGOALS))
all:
@$(MAKE) $(MAKEARGS) $(all) -f Makefile
Makefile:;
$(all): all
@:
%/: all
@:
build/linux-riscv-starlight$
Perhaps we could have a "make setup ARCH=foo CROSS_COMPILE=bar" target,
which creates such a GNUmakefile?
P.S. I put the extra logic in ~/linux/default.mk, so I don't have to update all
GNUmakefiles when I want to make a change to the main logic.
For build dirs where I want to track a specific config, I have a slightly
different version:
build/linux-m68k-allmodconfig-sun3$ cat GNUmakefile
MAKEARGS = ARCH=m68k KCONFIG_ALLCONFIG=1
DEFCONFIG = allmodconfig
include ~/linux/override-oldconfig.mk
build/linux-m68k-allmodconfig-sun3$ cat ~/linux/override-oldconfig.mk
MAKEFLAGS += --no-print-directory
.PHONY: all oldconfig realoldconfig $(MAKECMDGOALS)
all := $(filter-out all oldconfig realoldconfig
Makefile,$(MAKECMDGOALS))
all:
@$(MAKE) $(MAKEARGS) $(all) -f Makefile
# Replace oldconfig by $(DEFCONFIG)
oldconfig:
@$(MAKE) $(MAKEARGS) $(DEFCONFIG) -f Makefile
realoldconfig:
@$(MAKE) $(MAKEARGS) oldconfig -f Makefile
Makefile:;
$(all): all
@:
%/: all
@:
build/linux-m68k-allmodconfig-sun3$
That way I can always just type "make oldconfig", and it will do what
I want.
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
next prev parent reply other threads:[~2021-07-23 19:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-08 23:25 [PATCH v2 0/2] infer CROSS_COMPILE from SRCARCH for LLVM=1 LLVM_IAS=1 Nick Desaulniers
2021-07-08 23:25 ` [PATCH v2 1/2] Makefile: move initial clang flag handling into scripts/Makefile.clang Nick Desaulniers
2021-07-09 20:12 ` Nathan Chancellor
2021-07-08 23:25 ` [PATCH v2 2/2] Makefile: infer CROSS_COMPILE from SRCARCH for LLVM=1 LLVM_IAS=1 Nick Desaulniers
2021-07-09 20:44 ` Nathan Chancellor
2021-07-20 8:04 ` Masahiro Yamada
2021-07-20 17:30 ` Nathan Chancellor
2021-07-21 3:49 ` Masahiro Yamada
2021-07-28 18:59 ` Nick Desaulniers
2021-07-28 22:35 ` Masahiro Yamada
2021-07-20 17:42 ` Linus Torvalds
2021-07-20 19:58 ` Arnd Bergmann
2021-07-20 20:18 ` Nick Desaulniers
2021-07-21 4:04 ` Masahiro Yamada
2021-07-23 19:54 ` Geert Uytterhoeven [this message]
2021-07-24 13:46 ` Masahiro Yamada
2021-07-26 20:27 ` Eric W. Biederman
2021-07-27 7:07 ` Geert Uytterhoeven
2021-07-27 7:49 ` Arnd Bergmann
2021-07-27 7:55 ` Geert Uytterhoeven
2021-07-27 8:21 ` Arnd Bergmann
2021-07-27 10:10 ` Masahiro Yamada
2021-07-27 14:16 ` Eric W. Biederman
2021-07-27 15:45 ` Masahiro Yamada
2021-07-27 18:46 ` Eric W. Biederman
2021-07-28 22:31 ` Masahiro Yamada
2021-07-20 20:52 ` Nick Desaulniers
2021-07-20 21:11 ` Linus Torvalds
2021-07-20 21:27 ` Nick Desaulniers
2021-07-21 4:53 ` Masahiro Yamada
2021-07-20 21:29 ` Nick Desaulniers
2021-07-20 21:54 ` Linus Torvalds
2021-07-20 23:19 ` Linus Torvalds
2021-07-20 23:22 ` Linus Torvalds
2021-07-21 5:12 ` Masahiro Yamada
2021-07-21 4:52 ` Christoph Hellwig
2021-07-21 5:33 ` Masahiro Yamada
2021-07-21 4:31 ` Masahiro Yamada
2021-07-21 4:44 ` Christoph Hellwig
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