Re: [PATCH 4/4] xtensa: move core-y in arch/xtensa/Makefile to arch/xtensa/Kbuild

From: Masahiro Yamada
Date: Fri Aug 13 2021 - 03:10:32 EST


On Fri, Aug 13, 2021 at 2:32 PM Max Filippov <jcmvbkbc@xxxxxxxxx> wrote:
>
> On Wed, Aug 11, 2021 at 9:38 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> >
> > Use obj-y to clean up Makefile.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > ---
> >
> > arch/xtensa/Kbuild | 1 +
> > arch/xtensa/Makefile | 3 ---
> > arch/xtensa/platforms/Makefile | 4 ++++
> > 3 files changed, 5 insertions(+), 3 deletions(-)
> > create mode 100644 arch/xtensa/platforms/Makefile
> >
> > diff --git a/arch/xtensa/Kbuild b/arch/xtensa/Kbuild
> > index a4e40e534e6a..fd12f61745ba 100644
> > --- a/arch/xtensa/Kbuild
> > +++ b/arch/xtensa/Kbuild
> > @@ -1 +1,2 @@
> > # SPDX-License-Identifier: GPL-2.0-only
> > +obj-y += kernel/ mm/ platforms/ boot/dts/
> > diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
> > index 093e87b889be..96714ef7c89e 100644
> > --- a/arch/xtensa/Makefile
> > +++ b/arch/xtensa/Makefile
> > @@ -58,9 +58,6 @@ KBUILD_DEFCONFIG := iss_defconfig
> > LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> >
> > head-y := arch/xtensa/kernel/head.o
> > -core-y += arch/xtensa/kernel/ arch/xtensa/mm/
> > -core-y += arch/xtensa/platforms/$(platform-y)/
> > -core-y += arch/xtensa/boot/dts/
> >
> > libs-y += arch/xtensa/lib/ $(LIBGCC)
> >
> > diff --git a/arch/xtensa/platforms/Makefile b/arch/xtensa/platforms/Makefile
> > new file mode 100644
> > index 000000000000..e2e7e0726979
> > --- /dev/null
> > +++ b/arch/xtensa/platforms/Makefile
> > @@ -0,0 +1,4 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +obj-$(CONFIG_XTENSA_PLATFORM_XT2000) += xt2000/
> > +obj-$(CONFIG_XTENSA_PLATFORM_ISS) += iss/
> > +obj-$(CONFIG_XTENSA_PLATFORM_XTFPGA) += xtfpga/
>
> With this change platform directory names are duplicated in two
> makefiles. Can we move them to Kconfig with something like the
> following (on top of this change)?



I do not like the idea much for the following reasons.



- The string value in Kconfig is enclosed by double-quotes.

In the .config file,

CONFIG_XTENSA_PLATFORM="iss"


So, you are doing

obj-y += "iss"/

instead of

obj-y += iss/


Still, it seems working because the shell will eventually
get rid of double quotes, but that is not correct
from the Kbuild perspective.

You need to write like this:

obj-y += $(patsubst "%",%,$(CONFIG_XTENSA_PLATFORM))


- 'make clean' does not include any CONFIG option.

So,

obj-y += $(CONFIG_XTENSA_PLATFORM)/

will expand into:

obj-y += /


Luckily, Kbuild will ignore it.
Kbuild will not try to clean the root directory, but this code
scares me.

- Kbuild cannot know the sub-directories of arch/xtensa/platforms/.
So, you need to list the subdirectories anyway so 'make clean'
can visit all the sub-directories.

arch/xtensa/platforms/Makefile

# for 'make clean'
obj- += iss/ xt2000/ xtfpga/






> ---8<---
> diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
> index b843902ad9fd..fe5ae5ec71c9 100644
> --- a/arch/xtensa/Kconfig
> +++ b/arch/xtensa/Kconfig
> @@ -314,6 +314,12 @@ config PLATFORM_HAVE_XIP
>
> menu "Platform options"
>
> +config XTENSA_PLATFORM
> + string
> + default iss if XTENSA_PLATFORM_ISS
> + default xt2000 if XTENSA_PLATFORM_XT2000
> + default xtfpga if XTENSA_PLATFORM_XTFPGA
> +
> choice
> prompt "Xtensa System Type"
> default XTENSA_PLATFORM_ISS
> diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
> index 96714ef7c89e..6b104ecdd19e 100644
> --- a/arch/xtensa/Makefile
> +++ b/arch/xtensa/Makefile
> @@ -26,12 +26,6 @@ ifneq ($(VARIANT),)
> endif
> endif
>
> -# Platform configuration
> -
> -platform-$(CONFIG_XTENSA_PLATFORM_XT2000) := xt2000
> -platform-$(CONFIG_XTENSA_PLATFORM_ISS) := iss
> -platform-$(CONFIG_XTENSA_PLATFORM_XTFPGA) := xtfpga
> -
> # temporarily until string.h is fixed
> KBUILD_CFLAGS += -ffreestanding -D__linux__
> KBUILD_CFLAGS += -pipe -mlongcalls -mtext-section-literals
> @@ -47,7 +41,7 @@ endif
> CHECKFLAGS += -D$(if $(CONFIG_CPU_BIG_ENDIAN),__XTENSA_EB__,__XTENSA_EL__)
>
> vardirs := $(patsubst %,arch/xtensa/variants/%/,$(variant-y))
> -plfdirs := $(patsubst %,arch/xtensa/platforms/%/,$(platform-y))
> +plfdirs := $(patsubst %,arch/xtensa/platforms/%/,$(CONFIG_XTENSA_PLATFORM))
>
> KBUILD_CPPFLAGS += $(patsubst %,-I$(srctree)/%include,$(vardirs) $(plfdirs))
>
> diff --git a/arch/xtensa/platforms/Makefile b/arch/xtensa/platforms/Makefile
> index e2e7e0726979..08d0e9053db6 100644
> --- a/arch/xtensa/platforms/Makefile
> +++ b/arch/xtensa/platforms/Makefile
> @@ -1,4 +1,2 @@
> # SPDX-License-Identifier: GPL-2.0-only
> -obj-$(CONFIG_XTENSA_PLATFORM_XT2000) += xt2000/
> -obj-$(CONFIG_XTENSA_PLATFORM_ISS) += iss/
> -obj-$(CONFIG_XTENSA_PLATFORM_XTFPGA) += xtfpga/
> +obj-y += $(CONFIG_XTENSA_PLATFORM)/
>
> ---8<---
>
> --
> Thanks.
> -- Max



--
Best Regards
Masahiro Yamada