Re: [PATCH] kbuild: add dtbs_prepare target

[Dmitry Baryshkov]

On 16/07/2022 12:31, Masahiro Yamada wrote:
> Factor out the common prerequisites for DT compilation into the new
> target, dtbs_prepare.
>
> Add comments in case you wonder why include/config/kernel.release is
> the prerequisite. Our policy is that installation targets must not
> (re)compile any build artifacts in the tree. If we make modules_install
> depend on include/config/kernel.release and it is executed under the
> root privilege, it may be owned by root.
>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>

With the comment fixed:

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>

> ---
>
>   Makefile | 14 ++++++++++----
>   1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index a9bd55edb75e..8aa4dbb8f878 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1367,16 +1367,22 @@ endif
>   
>   ifneq ($(dtstree),)
>   
> -%.dtb: include/config/kernel.release scripts_dtc
> +%.dtb: dtbs_prepare
>   	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
>   
> -%.dtbo: include/config/kernel.release scripts_dtc
> +%.dtbo: dtbs_prepare
>   	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
>   
> -PHONY += dtbs dtbs_install dtbs_check
> -dtbs: include/config/kernel.release scripts_dtc
> +PHONY += dtbs dtbs_prepare dtbs_install dtbs_check
> +dtbs: dtbs_prepare
>   	$(Q)$(MAKE) $(build)=$(dtstree)
>   
> +# include/config/kernel.release is not actually required for building DTBs,
> +# but for installing DTBs because INSTALL_DTBS_PATH contains $(KERNELRELEASE).
> +# We do not want to move it to dtbs_install. The policy is installation
> +# targets (, which may run as root) must not modify the tree.
> +dtbs_prepare: include/config/kernel.release scripts_dtc
> +
>   ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),)
>   export CHECK_DTBS=y
>   dtbs: dt_binding_check


--
With best wishes
Dmitry