Re: [PATCH v2 0/2] kbuild: Show Kconfig fragments in "help"

[Masahiro Yamada]

On Tue, Aug 29, 2023 at 3:55 PM Nicolas Schier <nicolas@xxxxxxxxx> wrote:
>
> On Mon 28 Aug 2023 16:17:07 GMT, Michael Ellerman wrote:
> > Masahiro Yamada <masahiroy@xxxxxxxxxx> writes:
> > > On Sat, Aug 26, 2023 at 4:55 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >>
> > >> Hi,
> > >>
> > >> This is my series to show *.config targets in the "help" target so these
> > >> various topics can be more easily discoverd.
> > >>
> > >> v2:
> > >>  - split .fragment from .config to hide "internal" fragments
> > >
> > > Please do not do this churn.
> >
> > That was my idea :}
> >
> > > Like Randy, I did not get "why" part quiet well,
> > > but if you are eager about this,
> > > you can show help message only when the following
> > > ("# Help:" prefix for example) is found in the first line.
> > >
> > > # Help: blah blah
> > > # other comment
> >
> > I did think of that, but wasn't sure how to do it in make.
>
> Something like this should do it:
>
>         @grep -Hnm1 -e '^# Help:' $(foreach f, $(sort $(notdir $(call configfiles,*.config))), $(firstword $(call configfiles,$(f)))) | \
>          while read loc dummy helptext; do \
>                 tmp="$${loc%:#}"; file="$${tmp%:*}"; line="$${tmp##*:}"; \
>                 [ "$${line}" = "1" ] && \
>                   printf "  %-25s - %s\\n" "$${file##*/}" "$${helptext}"; \
>          done
>
> but this neither beautiful nor elegant it likes to be improved.
>
> Kind regards,
> Nicolas




The attached patch will work too.

I dropped the "in the first line" restriction
because SPDX might be placed in the first line
of config fragments.



-- 
Best Regards
Masahiro Yamada
diff --git a/Makefile b/Makefile
index e21bf66af6fd..23cd62a5ff05 100644
--- a/Makefile
+++ b/Makefile
@@ -1552,7 +1552,6 @@ help:
 	@echo  '  mrproper	  - Remove all generated files + config + various backup files'
 	@echo  '  distclean	  - mrproper + remove editor backup and patch files'
 	@echo  ''
-	@echo  'Configuration targets:'
 	@$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
 	@echo  ''
 	@echo  'Other generic targets:'
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index fdc2e3abd615..c4b2a8a19fc8 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -335,9 +335,5 @@ define archhelp
   echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
   echo  '			  FDARGS="..."  arguments for the booted kernel'
   echo  '			  FDINITRD=file initrd for the booted kernel'
-  echo  ''
-  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
-  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
-  echo  '  x86_debug.config	- Enable tip tree debugging options for testing'
 
 endef
diff --git a/kernel/configs/kvm_guest.config b/kernel/configs/kvm_guest.config
index 208481d91090..d0877063d925 100644
--- a/kernel/configs/kvm_guest.config
+++ b/kernel/configs/kvm_guest.config
@@ -1,3 +1,4 @@
+# Help: Bootable as a KVM guest
 CONFIG_NET=y
 CONFIG_NET_CORE=y
 CONFIG_NETDEVICES=y
diff --git a/kernel/configs/x86_debug.config b/kernel/configs/x86_debug.config
index 6fac5b405334..35f48671b8d5 100644
--- a/kernel/configs/x86_debug.config
+++ b/kernel/configs/x86_debug.config
@@ -1,3 +1,4 @@
+# Help: Debugging options for tip tree testing
 CONFIG_X86_DEBUG_FPU=y
 CONFIG_LOCK_STAT=y
 CONFIG_DEBUG_VM=y
diff --git a/kernel/configs/xen.config b/kernel/configs/xen.config
index 436f806aa1ed..6878b9a49be8 100644
--- a/kernel/configs/xen.config
+++ b/kernel/configs/xen.config
@@ -1,3 +1,5 @@
+# Help: Bootable as a Xen guest
+#
 # global stuff - these enable us to allow some
 # of the not so generic stuff below for xen
 CONFIG_PARAVIRT=y
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index af1c96198f49..e72c5ee659a9 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -93,11 +93,13 @@ 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))
+all-config-fragments = $(call configfiles,*)
+config-fragments = $(call configfiles,$@)
 
 %.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 $(config-fragments),, $(error $@ fragment does not exists on this architecture))
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(config-fragments)
 	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
 
 PHONY += tinyconfig
@@ -115,6 +117,7 @@ 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 +144,12 @@ 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 topic targets:'
+	@$(foreach f, $(all-config-fragments), \
+		if help=$$(grep -m1 '^# Help: ' $(f)); then \
+			printf '  %-25s - %s\n' '$(notdir $(f))' "$${help#*: }"; \
+		fi;)
 
 # ===========================================================================
 # object files used by all kconfig flavours