Date:   Mon, 13 May 2019 02:35:23 +0000
From:   Joel Stanley <joel@....id.au>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kbuild: terminate Kconfig when $(CC) or $(LD) is missing

On Mon, 13 May 2019 at 02:28, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
>
> On Thu, May 9, 2019 at 4:36 PM Masahiro Yamada
> <yamada.masahiro@...ionext.com> wrote:
> >
> > If the compiler specified by $(CC) is not present, the Kconfig stage
> > sprinkles 'not found' messages, then succeeds.
> >
> >   $ make CROSS_COMPILE=foo defconfig
> >   /bin/sh: 1: foogcc: not found
> >   /bin/sh: 1: foogcc: not found
> >   *** Default configuration is based on 'x86_64_defconfig'
> >   ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found
> >   ./scripts/clang-version.sh: 11: ./scripts/clang-version.sh: foogcc: not found
> >   ./scripts/gcc-plugin.sh: 11: ./scripts/gcc-plugin.sh: foogcc: not found
> >   init/Kconfig:16:warning: 'GCC_VERSION': number is invalid
> >   #
> >   # configuration written to .config
> >   #
> >
> > Terminate parsing files immediately if $(CC) or $(LD) is not found.
> > "make *config" will fail more nicely.
> >
> >   $ make CROSS_COMPILE=foo defconfig
> >   *** Default configuration is based on 'x86_64_defconfig'
> >   scripts/Kconfig.include:34: compiler 'foogcc' not found
> >   make[1]: *** [scripts/kconfig/Makefile;82: defconfig] Error 1
> >   make: *** [Makefile;557: defconfig] Error 2
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
> > ---
>
> Applied to linux-kbuild.

Thanks Masahiro! I had this in my inbox to test but you're too efficient.

Testing your patch on linus' tree as of today (d7a02fa0a8f9) gives me
this output:

$ CROSS_COMPILE=foo  make
make: foogcc: Command not found
scripts/kconfig/conf  --syncconfig Kconfig
scripts/Kconfig.include:34: compiler 'foogcc' not found
make[2]: *** [scripts/kconfig/Makefile:69: syncconfig] Error 1
make[1]: *** [Makefile:557: syncconfig] Error 2
make: *** [include/config/auto.conf.cmd] Deleting file
'include/config/tristate.conf'
make: Failed to remake makefile 'include/config/auto.conf'.
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
  HOSTCC  arch/x86/tools/relocs_32.o
  HOSTCC  arch/x86/tools/relocs_64.o
  HOSTCC  arch/x86/tools/relocs_common.o
  HOSTLD  arch/x86/tools/relocs
  UPD     include/config/kernel.release
  WRAP    arch/x86/include/generated/uapi/asm/bpf_perf_event.h
  WRAP    arch/x86/include/generated/uapi/asm/poll.h
  WRAP    arch/x86/include/generated/uapi/asm/socket.h
  WRAP    arch/x86/include/generated/uapi/asm/sockios.h
  WRAP    arch/x86/include/generated/asm/dma-contiguous.h
  WRAP    arch/x86/include/generated/asm/early_ioremap.h
  WRAP    arch/x86/include/generated/asm/export.h
  WRAP    arch/x86/include/generated/asm/mcs_spinlock.h
  WRAP    arch/x86/include/generated/asm/mm-arch-hooks.h
  WRAP    arch/x86/include/generated/asm/mmiowb.h
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  HOSTCC  scripts/selinux/genheaders/genheaders
  HOSTCC  scripts/selinux/mdp/mdp
  HOSTCC  scripts/kallsyms
  HOSTCC  scripts/pnmtologo
  HOSTCC  scripts/conmakehash
  HOSTCC  scripts/sortextable
  HOSTCC  scripts/asn1_compiler
  HOSTCC  scripts/extract-cert
You are building kernel with non-retpoline compiler.
Please update your compiler.
make: *** [arch/x86/Makefile:308: checkbin] Error 1

Which is a little confusing.

The second time is shorter, but the retpoline message is not ideal:

$ CROSS_COMPILE=foo  make
make: foogcc: Command not found
scripts/kconfig/conf  --syncconfig Kconfig
scripts/Kconfig.include:34: compiler 'foogcc' not found
make[2]: *** [scripts/kconfig/Makefile:69: syncconfig] Error 1
make[1]: *** [Makefile:557: syncconfig] Error 2
make: Failed to remake makefile 'include/config/auto.conf'.
You are building kernel with non-retpoline compiler.
Please update your compiler.

Cheers,

Joel

>
>
> >  Makefile                | 2 +-
> >  scripts/Kconfig.include | 8 ++++++++
> >  2 files changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 28965187c528..bd7ae11947cb 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -537,7 +537,7 @@ endif
> >  # Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
> >  # CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
> >  # and from include/config/auto.conf.cmd to detect the compiler upgrade.
> > -CC_VERSION_TEXT = $(shell $(CC) --version | head -n 1)
> > +CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)
> >
> >  ifeq ($(config-targets),1)
> >  # ===========================================================================
> > diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
> > index 87ff1dcc6bd5..0b267fb27f07 100644
> > --- a/scripts/Kconfig.include
> > +++ b/scripts/Kconfig.include
> > @@ -18,6 +18,10 @@ if-success = $(shell,{ $(1); } >/dev/null 2>&1 && echo "$(2)" || echo "$(3)")
> >  # Return y if <command> exits with 0, n otherwise
> >  success = $(if-success,$(1),y,n)
> >
> > +# $(failure,<command>)
> > +# Return n if <command> exits with 0, y otherwise
> > +failure = $(if-success,$(1),n,y)
> > +
> >  # $(cc-option,<flag>)
> >  # Return y if the compiler supports <flag>, n otherwise
> >  cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
> > @@ -26,5 +30,9 @@ cc-option = $(success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null)
> >  # Return y if the linker supports <flag>, n otherwise
> >  ld-option = $(success,$(LD) -v $(1))
> >
> > +# check if $(CC) and $(LD) exist
> > +$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
> > +$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
> > +
> >  # gcc version including patch level
> >  gcc-version := $(shell,$(srctree)/scripts/gcc-version.sh $(CC))
> > --
> > 2.17.1
> >
>
>
> --
> Best Regards
> Masahiro Yamada

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