linux-kernel - Re: [PATCH] powerpc: use always-y instead of extra-y in Makefiles

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Message-ID: <CAK7LNARhhw7pg+ymaSdniXwfBbHUoAkOJiwFzuGVRoN01KhHnw@mail.gmail.com>
Date: Mon, 9 Jun 2025 13:31:43 +0900
From: Masahiro Yamada <masahiroy@...nel.org>
To: Michael Ellerman <mpe@...erman.id.au>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>, Madhavan Srinivasan <maddy@...ux.ibm.com>, 
	Nicholas Piggin <npiggin@...il.com>, Naveen N Rao <naveen@...nel.org>, linuxppc-dev@...ts.ozlabs.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] powerpc: use always-y instead of extra-y in Makefiles

On Mon, Jun 9, 2025 at 10:02 AM Michael Ellerman <mpe@...erman.id.au> wrote:
>
> Masahiro Yamada <masahiroy@...nel.org> writes:
> > On Tue, Jun 3, 2025 at 3:50 PM Christophe Leroy
> > <christophe.leroy@...roup.eu> wrote:
> >> Le 02/06/2025 à 18:32, Masahiro Yamada a écrit :
> >> > The extra-y syntax is planned for deprecation because it is similar
> >> > to always-y.
> >> >
> >> > When building the boot wrapper, always-y and extra-y are equivalent.
> >> > Use always-y instead.
> >> >
> >> > In arch/powerpc/kernel/Makefile, I added ifdef KBUILD_BUILTIN to
> >> > keep the current behavior: prom_init_check is skipped when building
> >> > only modular objects.
> >>
> >> I don't understand what you mean.
> >>
> >> CONFIG_PPC_OF_BOOT_TRAMPOLINE is a bool, it cannot be a module.
> >>
> >> prom_init_check is only to check the content of prom_init.o which is
> >> never a module.
> >>
> >> Is always-y to run _after_ prom_init.o is built ?
> >
> > The intent of "make ARCH=powerpc modules"
> > is to compile objects that are necessary for modules,
> > that is, all built-in objects are skipped.
> >
> > However,
> > always-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE) += prom_init_check
> > would generate prom_init_check regardless,
> > and its prerequisite, prom_init.o as well.
> >
> > With CONFIG_MODULES=y and
> > CONFIG_MODVERSIONS=n,
> > and without ifdef KBUILD_BUILTIN,
> >
> > $ make ARCH=powerpc CROSS_COMPILE=powerpc64-linux-gnu-   modules
> >
> > would result in this:
> >
> >
> >   CC [M]  arch/powerpc/kvm/book3s_xive_native.o
> >   CC [M]  arch/powerpc/kvm/book3s_64_vio.o
> >   LD [M]  arch/powerpc/kvm/kvm.o
> >   CC [M]  arch/powerpc/kvm/book3s_hv.o
> >   AS [M]  arch/powerpc/kvm/book3s_hv_interrupts.o
> >   CC [M]  arch/powerpc/kvm/book3s_64_mmu_hv.o
> >   CC [M]  arch/powerpc/kvm/book3s_64_mmu_radix.o
> >   CC [M]  arch/powerpc/kvm/book3s_hv_nested.o
> >   CC [M]  arch/powerpc/kvm/book3s_hv_tm.o
> >   LD [M]  arch/powerpc/kvm/kvm-hv.o
> >   CC [M]  arch/powerpc/kernel/rtas_flash.o
> >   CC      arch/powerpc/kernel/prom_init.o
> >   PROMCHK arch/powerpc/kernel/prom_init_check
> >   CC [M]  kernel/locking/locktorture.o
> >   CC [M]  kernel/time/test_udelay.o
> >   CC [M]  kernel/time/time_test.o
> >   CC [M]  kernel/backtracetest.o
> >   CC [M]  kernel/torture.o
> >   CC [M]  kernel/resource_kunit.o
> >   CC [M]  kernel/sysctl-test.o
> >   CC [M]  fs/ext4/inode-test.o
> >   LD [M]  fs/ext4/ext4-inode-test.o
> >   CC [M]  fs/fat/namei_vfat.o
> >   LD [M]  fs/fat/vfat.o
> >   CC [M]  fs/fat/fat_test.o
> >   CC [M]  fs/nls/nls_ucs2_utils.o
> >   CC [M]  fs/netfs/buffered_read.o
> >   CC [M]  fs/netfs/buffered_write.o
> > ...
> >
> >
> >
> > You can see these two lines:
> >
> >   CC      arch/powerpc/kernel/prom_init.o
> >   PROMCHK arch/powerpc/kernel/prom_init_check
> >
> > are supposed to be skipped when "make modules",
> > but actually compiled without ifdef.
> >
> > So, I added ifdef KBUILD_BUILTIN to preserve
> > the current behavior.
>
> OK, that makes sense.
>
> I don't really ever build just modules, so I wouldn't notice, but some
> folks probably do.
>
> Acked-by: Michael Ellerman <mpe@...erman.id.au> (powerpc)

No rush for this patch.
Please take it to your ppc tree.
Thank you.

-- 
Best Regards
Masahiro Yamada