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

Kees Cook
2023-08-25T18:24:15Z

On Fri, Aug 25, 2023 at 07:44:06AM +0200, Nicolas Schier wrote:
> On Thu, Aug 24, 2023 at 03:36:10PM -0700, Kees Cook wrote:
> > 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.
> > [...]
>
> Thanks for that patch! Several times I found myself searching the tree
> to find a specific kconfig fragment; I think you found a nice solution.
> Two minor things below.
>
> [...]
> > diff --git a/kernel/configs/tiny-base.config b/kernel/configs/tiny-base.config
> > index 2f0e6bf6db2c..ac4d254abc3f 100644
> > --- a/kernel/configs/tiny-base.config
> > +++ b/kernel/configs/tiny-base.config
> > @@ -1 +1,2 @@
> > +# Minimal options for tiny systems
> > CONFIG_EMBEDDED=y
>
> (just a note: Randy prepared a patch for removing CONFIG_EMBEDDED:
> https://lore.kernel.org/linux-kbuild/20230816055010.31534-1-rdunlap@infradead.org/)

Ah yeah, I'll rebase this after the merge window, I guess...

> > diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config
> > index 00009f7d0835..ea643e8f7f14 100644
> > --- a/kernel/configs/tiny.config
> > +++ b/kernel/configs/tiny.config
> > @@ -1,3 +1,5 @@
> > +# Smallest possible kernel image
>
> For this fragment alone (not within 'tinyconfig'), "Size-optimize kernel
> image" possibly fits better?

Sounds good to me!

> > diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
> > index af1c96198f49..c523f24b504a 100644
> > --- a/scripts/kconfig/Makefile
> > +++ b/scripts/kconfig/Makefile
> > @@ -93,11 +93,11 @@ endif
> > %_defconfig: $(obj)/conf
> > $(Q)$< $(silent) --defconfig=arch/$(SRCARCH)/configs/$@ $(Kconfig)
> >
> > -configfiles=$(wildcard $(srctree)/kernel/configs/$@ $(srctree)/arch/$(SRCARCH)/configs/$@)
> > +configfiles=$(wildcard $(srctree)/kernel/configs/$(1) $(srctree)/arch/$(SRCARCH)/configs/$(1))
> >
> > %.config: $(obj)/conf
> > - $(if $(call configfiles),, $(error No configuration exists for this target on this architecture))
> > - $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(configfiles)
> > + $(if $(call configfiles,$@),, $(error No configuration exists for this target on this architecture))
> > + $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(call configfiles,$@)
> > $(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
> >
> > PHONY += tinyconfig
> > @@ -115,6 +115,7 @@ clean-files += tests/.cache
> >
> > # Help text used by make help
> > help:
> > + @echo 'Configuration targets:'
> > @echo ' config - Update current config utilising a line-oriented program'
> > @echo ' nconfig - Update current config utilising a ncurses menu based program'
> > @echo ' menuconfig - Update current config utilising a menu based program'
> > @@ -141,6 +142,12 @@ help:
> > @echo ' default value without prompting'
> > @echo ' tinyconfig - Configure the tiniest possible kernel'
> > @echo ' testconfig - Run Kconfig unit tests (requires python3 and pytest)'
> > + @echo ''
> > + @echo 'Configuration fragment targets (for enabling various Kconfig items):'
> > + @$(foreach c, $(call configfiles,*.config), \
> > + printf " %-20s - %s\\n" \
> > + $(shell basename $(c)) \
> > + "$(subst # ,,$(shell grep -m1 '^# ' $(c)))";)
>
> Better use '$(notdir $(c))` instead of forking a shell with
> '$(shell basename $(c))'.

Ah! Thank you. I *knew* there was a function for this but couldn't find
it for some reason. :)

--
Kees Cook