[PATCH v2 1/2] kbuild: make collect-policies lightweight with standalone Makefile.policy

[Sascha Hauer]

On Thu, Feb 26, 2026 at 09:49:17AM +0100, Sascha Hauer wrote:
> From: Claude <noreply at anthropic.com>

Should be me.

From: Sascha Hauer <s.hauer at pengutronix.de>

Sascha

> 
> collect-policies previously depended on $(barebox-dirs), which requires
> `prepare scripts` and triggers unnecessary rebuilds. Repurpose
> Makefile.policy to support dual-mode operation: when invoked standalone
> it bootstraps kbuild infrastructure and recurses through subdirectories
> (like Makefile.clean), and when included from Makefile.build it provides
> the existing build-time .sconfig rules.
> 
> Replace the collect-policies target to use lightweight _policy_collect_
> prefixed dirs with no build prerequisites.
> 
> Co-Authored-By: Claude Opus 4.6 <noreply at anthropic.com>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  Makefile                | 24 +++++++++++++-------
>  scripts/Makefile.policy | 58 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 74 insertions(+), 8 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 4296c97ef0..4bf77896b6 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1133,7 +1133,6 @@ $(sort $(BAREBOX_OBJS)) $(BAREBOX_LDS) $(BAREBOX_PBL_OBJS): $(barebox-dirs) ;
>  
>  PHONY += $(barebox-dirs)
>  $(barebox-dirs): prepare scripts
> -	@find $(objtree)/$@ -name policy-list -exec rm -f {} \; 2>/dev/null || true
>  	$(Q)$(MAKE) $(build)=$@
>  
>  # Store (new) KERNELRELASE string in include/config/kernel.release
> @@ -1228,12 +1227,17 @@ targets += include/generated/security_autoconf.h
>  targets += include/generated/sconfig_names.h
>  
>  KPOLICY = $(shell find $(objtree)/ -name policy-list -exec cat {} \;)
> -KPOLICY.tmp = $(addsuffix .tmp,$(KPOLICY))
>  
> -PHONY += collect-policies
> -collect-policies: KBUILD_MODULES :=
> -collect-policies: KBUILD_BUILTIN :=
> -collect-policies: $(barebox-dirs) FORCE
> +collect-dirs    := $(addprefix _policy_collect_,$(barebox-alldirs))
> +
> +PHONY += _policy_collect_clean $(collect-dirs) collect-policies
> +_policy_collect_clean:
> +	$(Q)find $(objtree)/ -name policy-list -delete 2>/dev/null || true
> +
> +$(collect-policy-dirs): | _policy_collect_clean
> +	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.policy obj=$(patsubst _policy_collect_%,%,$@)
> +
> +collect-policies: $(collect-policy-dirs)
>  
>  PHONY += security_listconfigs
>  security_listconfigs: collect-policies FORCE
> @@ -1241,11 +1245,15 @@ security_listconfigs: collect-policies FORCE
>  	@$(foreach p, $(KPOLICY), echo $p ;)
>  
>  PHONY += security_checkconfigs
> -security_checkconfigs: collect-policies $(KPOLICY.tmp) FORCE
> +security_checkconfigs: collect-policies FORCE
> +	+$(Q)$(foreach p, $(KPOLICY), \
> +		$(MAKE) $(build)=$(patsubst %/,%,$(dir $p)) $p.tmp ;)
>  	+$(Q)$(foreach p, $(KPOLICY), \
>  		$(call loop_cmd,security_checkconfig,$p.tmp))
>  
> -security_%config: collect-policies $(KPOLICY.tmp) FORCE
> +security_%config: collect-policies FORCE
> +	+$(Q)$(foreach p, $(KPOLICY), \
> +		$(MAKE) $(build)=$(patsubst %/,%,$(dir $p)) $p.tmp ;)
>  	+$(Q)$(foreach p, $(KPOLICY), $(call loop_cmd,sconfig, \
>  		$(@:security_%=%),$p.tmp))
>  ifeq ($(KPOLICY_TMPUPDATE),)
> diff --git a/scripts/Makefile.policy b/scripts/Makefile.policy
> index e517feb56e..f2c6b204d5 100644
> --- a/scripts/Makefile.policy
> +++ b/scripts/Makefile.policy
> @@ -1,5 +1,61 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  
> +# When invoked standalone (make -f Makefile.policy obj=dir), bootstrap
> +# the kbuild infrastructure and handle recursion. When included from
> +# Makefile.build, skip straight to the rules.
> +
> +ifndef build
> +# Standalone mode — collect policies without building
> +
> +src := $(obj)
> +
> +PHONY := __collect
> +__collect:
> +
> +policy-y :=
> +
> +include scripts/Kbuild.include
> +
> +# Include Kconfig output so CONFIG_* symbols (e.g. CONFIG_SECURITY_POLICY_PATH)
> +# are available when security/Makefile computes external-policy.
> +-include include/config/auto.conf
> +
> +kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
> +include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)
> +
> +__subdir-y	:= $(patsubst %/,%,$(filter %/, $(obj-y)))
> +subdir-y	+= $(__subdir-y)
> +__subdir-m	:= $(patsubst %/,%,$(filter %/, $(obj-m)))
> +subdir-m	+= $(__subdir-m)
> +
> +subdir-ym	:= $(sort $(subdir-y) $(subdir-m))
> +subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
> +
> +real-policy-y	:= $(addprefix $(obj)/,$(policy-y))
> +
> +# external-policy is set by security/Makefile from CONFIG_SECURITY_POLICY_PATH
> +real-external-policy := $(addprefix $(obj)/,$(external-policy))
> +all-policy	:= $(real-policy-y) $(real-external-policy)
> +
> +quiet_cmd_collect = COLLECT $(obj)
> +      cmd_collect = { $(foreach p,$(all-policy),echo $(p);) :; } > $(obj)/policy-list
> +
> +__collect: $(subdir-ym)
> +ifneq ($(strip $(all-policy)),)
> +	$(Q)mkdir -p $(obj)
> +	$(call cmd,collect)
> +endif
> +	@:
> +
> +PHONY += $(subdir-ym)
> +$(subdir-ym):
> +	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.policy obj=$@
> +
> +.PHONY: $(PHONY)
> +
> +else
> +# Included from Makefile.build — provide build-time rules
> +
>  real-policy-y   := $(addprefix $(obj)/, $(policy-y))
>  
>  targets         += $(addsuffix .tmp, $(real-policy-y))
> @@ -36,3 +92,5 @@ $(obj)/%.sconfig.c: $(obj)/%.sconfig.tmp FORCE
>  # ---------------------------------------------------------------------------
>  
>  targets += $(always-y)
> +
> +endif # build
> 
> -- 
> 2.47.3
> 
> 

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