[PATCH 02/10] kconfig: Add scripts/Kconfig.include from v4.19

[Masahiro Yamada]

On Tue, May 19, 2020 at 1:55 AM Tom Rini <trini at konsulko.com> wrote:
>
> On Mon, May 18, 2020 at 11:23:20AM -0400, Tom Rini wrote:
> > On Mon, May 18, 2020 at 11:55:11AM +0900, Masahiro Yamada wrote:
> > > Tom,
> > >
> > >
> > >
> > > On Thu, May 14, 2020 at 9:32 PM Tom Rini <trini at konsulko.com> wrote:
> > > >
> > > > As part of re-syncing our Kconfig logic up to v4.19, we had missed
> > > > adding this new file that includes helper macros.  To quote the upstream
> > > > commit e1cfdc0e72fc ("kconfig: add basic helper macros to scripts/Kconfig.include"):
> > > >
> > > > Kconfig got text processing tools like we see in Make.  Add Kconfig
> > > > helper macros to scripts/Kconfig.include like we collect Makefile
> > > > macros in scripts/Kbuild.include.
> > > >
> > > > Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
> > > > Signed-off-by: Tom Rini <trini at konsulko.com>
> > >
> > >
> > > If you want to align with Linux kernel, please go ahead.
> > >
> > >
> > > Some notes.
> > >
> > >
> > > Previously, CROSS_COMPILE was not required at the Kconfig stage.
> > >
> > > So, people was able to do this:
> > >
> > >       make qemu_arm64_defconfig
> > >       make CROSS_COMPILE=aarch64-linux-gnu-
> > >
> > >
> > > Going forward, Kconfig requires CROSS_COMPILE set correctly.
> > >
> > >       make CROSS_COMPILE=aarch64-linux-gnu-  qemu_arm64_defconfig
> > >       make CROSS_COMPILE=aarch64-linux-gnu-
> > >
> > > Maybe, passing CROSS_COMPILE as an environment variable is handier
> > >
> > >       export CROSS_COMPILE=aarch64-linux-gnu-
> > >       make qemu_arm64_defconfig
> > >       make
> > >
> > >
> > >
> > >
> > >
> > > When you upgrade the compiler, in theory,
> > > you must re-run Kconfig because the .config now
> > > contains the compiler information.
> > >
> > > If you want to do this automatically,
> > > you can import CC_VERSION_TEXT.
> > >
> > > Specifically, the following two commits:
> > > 21c54b774744719c386fbdc829b0e7759edb8ece
> > > 315bab4e972d9795529b764718d475492db40c0f
> >
> > OK, so we really want to grab those changes as well at the time, thanks!
>
> Trying this out and trying to follow the code a bit, the first commit is
> helpful for us in that it's good to have the compiler noted in the file.
> But even without it, with this series applied we see:
> $ make O=/tmp/rpi3_32b HOSTCC=clang-10 CROSS_COMPILE=~/.buildman-toolchains/gcc-9.2.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-  CC="clang-10 -target arm-linux-gnueabi" rpi_3_32b_config
> make[1]: Entering directory '/tmp/rpi3_32b'
>   HOSTCC  scripts/basic/fixdep
>   GEN     ./Makefile
>   HOSTCC  scripts/kconfig/conf.o
>   YACC    scripts/kconfig/zconf.tab.c
>   LEX     scripts/kconfig/zconf.lex.c
>   HOSTCC  scripts/kconfig/zconf.tab.o
>   HOSTLD  scripts/kconfig/conf
> #
> # configuration written to .config
> #
> make[1]: Leaving directory '/tmp/rpi3_32b'
> $ make O=/tmp/rpi3_32b HOSTCC=clang-10 CROSS_COMPILE=~/.buildman-toolchains/gcc-9.2.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-
> make[1]: Entering directory '/tmp/rpi3_32b'
>   GEN     ./Makefile
> scripts/kconfig/conf  --syncconfig Kconfig
>   UPD     include/config.h
>   CFG     u-boot.cfg
> ...
>
>
> So we're getting syncconfig run and CC-related changes are caught.


This is because you changed the environment variable, $(CC).


I meant the situation, "the compiler version is updated
without changing the installation path".


I think this does not happen quite often, but I assumed the
following scenario.

- "apt-get upgrade" will upgrade distro compilers.
  The executables in /usr/bin/ are overwritten.

- If you have cross compilers in $(HOME)/bin etc.,
  you may want to simply overwrite to upgrade the compilers.



> For the second commit, since ARCH comes from CONFIG_SYS_ARCH and not the
> make line/environment, we don't have that problem to start with?
> Thanks!


Sorry, I missed ARCH comes from CONFIG_SYS_ARCH in U-Boot.
That is a difference from Linux.



arch/*/config.mk define CROSS_COMPILE.


arch/m68k/config.mk:ifeq ($(CROSS_COMPILE),)
arch/m68k/config.mk:CROSS_COMPILE := m68k-elf-
arch/microblaze/config.mk:ifeq ($(CROSS_COMPILE),)
arch/microblaze/config.mk:CROSS_COMPILE := mb-
arch/nds32/config.mk:ifeq ($(CROSS_COMPILE),)
arch/nds32/config.mk:CROSS_COMPILE := nds32le-linux-
arch/nios2/config.mk:ifeq ($(CROSS_COMPILE),)
arch/nios2/config.mk:CROSS_COMPILE := nios2-elf-
arch/powerpc/config.mk:ifeq ($(CROSS_COMPILE),)
arch/powerpc/config.mk:CROSS_COMPILE := ppc_8xx-
arch/powerpc/config.mk:ifeq ($(CROSS_COMPILE),powerpc-netbsd-)
arch/powerpc/config.mk:ifeq ($(CROSS_COMPILE),powerpc-openbsd-)
arch/sh/config.mk:ifeq ($(CROSS_COMPILE),)
arch/sh/config.mk:CROSS_COMPILE := sh4-linux-
arch/x86/cpu/config.mk:CROSS_COMPILE ?= i386-linux-
arch/xtensa/config.mk:CROSS_COMPILE ?= xtensa-linux-



If you apply patch, you cannot support
CROSS_COMPILE defines in arch/*/config.mk



U-Boot determines SYS_ARCH from Kconfig.
After Kconfig, the build system can include
the correct arch/*/config.mk, but it is too late
to pick up CROSS_COMPILE.



-- 
Best Regards
Masahiro Yamada