Re: [PATCH] kbuild: Show Kconfig fragments in "help"

Kees Cook
2023-08-25T18:34:33Z

On Fri, Aug 25, 2023 at 04:11:58PM +1000, Michael Ellerman wrote:
> Kees Cook <keescook@chromium.org> writes:
> > Doing a "make help" would show only hard-coded Kconfig targets and
> > depended on the archhelp target to include ".config" targets. There was
> > nothing showing global kernel/configs/ targets. Solve this by walking
> > the wildcard list and include them in the output, using the first comment
> > line as the help text.
> >
> > Update all Kconfig fragments to include help text and adjust archhelp
> > targets to avoid redundancy.
> >
> > Adds the following section to "help" target output:
> >
> > Configuration fragment targets (for enabling various Kconfig items):
> > debug.config - Debugging for CI systems and finding regressions
> > kvm_guest.config - Bootable as a KVM guest
> > nopm.config - Disable Power Management
> > rust.config - Enable Rust
> > tiny-base.config - Minimal options for tiny systems
> > tiny.config - Smallest possible kernel image
> > x86_debug.config - Debugging options for tip tree testing
> > xen.config - Bootable as a Xen guest
> > tiny.config - x86-specific options for a small kernel image
> > xen.config - x86-specific options for a Xen virtualization guest
>
> I think we need a way to opt some files out.
>
> It's a bit ugly on powerpc because there are so many fragments:
>
> Configuration fragment targets (for enabling various Kconfig items):
> debug.config - Debugging for CI systems and finding regressions
> kvm_guest.config - Bootable as a KVM guest
> nopm.config - Disable Power Management
> rust.config - Enable Rust
> tiny-base.config - Minimal options for tiny systems
> tiny.config - Smallest possible kernel image
> x86_debug.config - Debugging options for tip tree testing
> xen.config - Bootable as a Xen guest
> 32-bit.config - Build a 32-bit image
> 64-bit.config - Build a 64-bit image
> 85xx-32bit.config - Build a 32-bit 85xx image
> 85xx-64bit.config - Build a 64-bit 85xx image
> 85xx-hw.config - Base hardware support for 86xx
> 85xx-smp.config - Enable SMP on 85xx
> 86xx-hw.config - Base hardware support for 86xx
> 86xx-smp.config - Enable SMP on 86xx
> altivec.config - Enable Altivec support
> be.config - Enable Big Endian mode
> book3s_32.config - Base support for Book3s
> corenet_base.config - Base support for corenet
> debug.config - Enable PowerPC specific debug options
> disable-werror.config - Disable -Werror
> dpaa.config - Base suppot for DPPA
> fsl-emb-nonhw.config - Non-hardware options common to 85xx and corenet
> guest.config - PowerPC specific virtualization guest options
> kvm_guest.config - Bootable as a KVM guest
> le.config - Enable Little Endian mode
> mpc85xx_base.config - Base mpc85xxx support
> mpc86xx_base.config - Base mpc85xxx support
> ppc64le.config - Enable ppc64le mode
> security.config - Common security options for PowerPC builds
>
> And some of those are not intended for use with "make foo.config",
> they're used internally for generating our "normal" defconfigs and they
> don't necessarily work on their own.
>
> Also I'd like to add more fragments in future, to the point where nearly
> all our configs are generated by them.
>
> Can we have some way to differentiate fragments that are intended to be
> used with "make foo.config" vs just being used internally to generate
> other configs.
>
> The obvious thing would be to use a different suffix, eg. "foo.fragment"
> for internal use fragments. That would require changing
> merge_into_defconfig and merge_into_defconfig_override to not assume the
> .config suffix, and update the users in arm, arm64 and powerpc.
>
> The other option would be to ignore .config files starting with eg. "_".
>
> + @$(foreach c, $(filter-out $(call configfiles,_*.config),$(call configfiles,*.config)), \
> + printf " %-20s - %s\\n" \
> + $(shell basename $(c)) \
> + "$(subst # ,,$(shell grep -m1 '^# ' $(c)))";)
>
> Not sure which is preferable.

Yeah, I wasn't too happy about some of these results. There seems to be
three cases a fragment:

- user-visible make target
- used internally
- arch-specific settings for a user-visible make target (redundant)

Only the first should be visible. The trouble is that some user-visible
targets are arch-specific.

I think I like your idea of having both .config and .fragment... I'll
give that a try and see how it looks.

--
Kees Cook